JP2009124112A - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device and method of manufacturing it, in which a plurality of elements with different element characteristics can be integrated, and a crack can be inhibited, in a configuration in which a plurality of elements including at least a double-sided electrode element are formed in one semiconductor substrate. <P>SOLUTION: The semiconductor device which is provided with: a semiconductor substrate; insulating separation trenches which surround a plurality of element formation regions in the semiconductor substrate, respectively, and penetrate the semiconductor substrate to insulate and separate a plurality of the element formation regions from one another; and elements which are constructed in a plurality of the element formation regions in which a plurality of thickness regions with thickness different from one another are constructed in the semiconductor substrate. Further, the element formation regions are formed in at least two thickness regions including the region with the thinnest thickness among a plurality of thickness regions, respectively. The configuration includes at least a double-sided electrode element as an element, wherein the double-sided electrode element is formed in at least the region with the thinnest thickness. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor device in which a plurality of elements are formed on one semiconductor substrate and a method for manufacturing the same.

Conventionally, as disclosed in Patent Document 1, for example, a semiconductor device (composite IC) in which a plurality of elements are formed on one semiconductor substrate has been proposed. In the semiconductor device disclosed in Patent Document 1, an SOI (Silicon On Insulator) substrate in which a thin silicon layer is disposed on a silicon substrate via a buried insulating film (silicon oxide film) is employed as a semiconductor substrate. A trench reaching the buried insulating film is formed in the silicon layer, and the trench is filled with polysilicon via a silicon oxide film to form an insulating isolation trench. The insulating isolation trench and the buried insulating film divide a plurality of element forming regions in the silicon layer, and elements such as an up drain MOSFET, an NPN transistor, and an nMOS and a pMOS constituting a CMOS are formed in the element forming region. .
JP 2001-60634 A

  By the way, in the case of an SOI substrate, a plurality of element formation regions can be partitioned in the silicon layer by the insulating isolation trench and the buried insulating film, so that a pair of electrodes are arranged on one side of the substrate surface. Suitable for device formation. However, since the current flowing in the thickness direction of the semiconductor substrate is blocked by the buried insulating film, the pair for driving these elements is used for high current power applications such as vertical MOS transistor elements and IGBT elements. It is not suitable for forming a double-sided electrode element in which the electrodes formed are arranged separately on the surfaces on both sides of the semiconductor substrate.

  On the other hand, the present applicant has proposed a semiconductor device in which a plurality of elements including at least double-sided electrode elements are formed on one semiconductor substrate and a manufacturing method thereof in Japanese Patent Application Laid-Open No. 2008-166705. In this semiconductor device, a bulk semiconductor substrate having a predetermined thickness is prepared, and a non-penetrating insulating isolation trench is formed from the main surface side of the semiconductor substrate so as to surround a plurality of element formation regions. Then, the semiconductor substrate is polished from the back surface side of the main surface until the front end of the non-penetrating insulation isolation trench is exposed, thereby bringing the insulation isolation trench into a through state. As a result, a semiconductor device can be obtained in which the thickness of the semiconductor substrate is set to a predetermined thickness and the elements are respectively formed in a plurality of element forming regions partitioned by the insulating isolation trenches.

  However, in the above, the entire semiconductor substrate is made uniform by polishing. Therefore, when integrating a plurality of elements including at least a double-sided electrode element (an element in which a current flows in the thickness direction of the semiconductor substrate) on the semiconductor substrate, a plurality of elements having different characteristics such as withstand voltage and on-resistance are integrated. It is difficult. For example, it is difficult to integrate a plurality of IGBT elements having different breakdown voltages.

  In addition, in order to reduce the on-resistance of the double-sided electrode element, if the entire thickness is reduced, the mechanical strength is insufficient, and there is a risk of cracking during dicing or conveyance.

  In view of the above problems, the present invention can integrate a plurality of elements having different element characteristics and suppress cracks in a configuration in which a plurality of elements including at least double-sided electrode elements are formed on one semiconductor substrate. An object of the present invention is to provide a semiconductor device and a manufacturing method thereof.

  In order to achieve the above object, the invention according to claim 1 is an insulating device that surrounds a semiconductor substrate and a plurality of element formation regions in the semiconductor substrate, and insulates and isolates the plurality of element formation regions from each other through the semiconductor substrate. A semiconductor device including an isolation trench and an element configured in each of a plurality of element formation regions, wherein the semiconductor substrate has a plurality of thickness regions having different thicknesses, and the plurality of thickness regions Among them, an element formation region is formed in at least two thickness regions including the thinnest region, and as a device, at least the thinnest region is formed, and a pair of electrodes is connected to the main surface of the semiconductor substrate. It includes a double-sided electrode element arranged separately on the back surface of the main surface.

  As described above, according to the present invention, a plurality of thickness regions having different thicknesses are formed on one semiconductor substrate, and element formation regions are formed in at least two thickness regions. Therefore, each element can be formed by being distributed into a thickness region having a thickness suitable for the characteristics of each element such as withstand voltage and on-resistance. Moreover, the double-sided electrode element is formed in at least the thinnest region among at least two thickness regions where the element formation region is formed. Therefore, in a configuration including at least double-sided electrode elements as a plurality of elements, current can easily flow between electrodes forming a pair of double-sided electrode elements. As described above, in a configuration in which a plurality of elements including at least double-sided electrode elements are formed on one semiconductor substrate, a semiconductor device in which a plurality of elements having different element characteristics are integrated can be obtained.

  The on-resistance of the double-sided electrode element can be lowered as the semiconductor substrate is thinner. However, if the thickness of the thinnest region where the double-sided electrode elements are formed is made uniform over the entire semiconductor substrate, the mechanical strength is insufficient, and cracking may occur during dicing or transportation. Further, if the mechanical strength is to be ensured, the semiconductor substrate becomes thick and it becomes difficult to lower the on-resistance to a desired value. On the other hand, according to the present invention, the semiconductor substrate has not only the thinnest region but also the thicker region, so that the mechanical strength can be improved. That is, it is possible to suppress cracking of the semiconductor substrate.

  According to a second aspect of the present invention, the double-sided electrode element may include a vertical MOS transistor element or an IGBT element. According to this, it can be set as a semiconductor device provided with the double-sided electrode element made low on-resistance. In addition to the above, as the double-sided electrode element, a diode, a resistor, a wiring, or the like can be employed.

  The double-sided electrode element may be formed in a plurality of thickness regions including the thinnest region, respectively. According to this, for example, a semiconductor device in which double-sided electrode elements having different withstand voltages are integrated can be obtained.

  According to a fourth aspect of the present invention, the element includes a single-sided electrode element in which pairs of electrodes are arranged together on the main surface of the semiconductor substrate, and the single-sided electrode element has a thickness region in which the double-sided electrode element is formed, May be formed in at least one of different thickness regions. According to this, it is possible to provide a semiconductor device in which double-sided electrode elements having different withstand voltages are integrated on one semiconductor substrate and single-sided electrode elements are also integrated.

  In addition, as described in claim 5, the element includes a single-sided electrode element in which a pair of electrodes are arranged together on the main surface of the semiconductor substrate together with the double-sided electrode element, and the plurality of double-sided electrode elements are the thickest. The single-sided electrode element may be formed in at least one of the thickness regions different from the thickness region where the double-sided electrode element is formed. According to this, a semiconductor device (composite IC) in which a double-sided electrode element and a single-sided electrode element are integrated on one semiconductor substrate can be obtained.

  As the single-sided electrode element, as described in claim 6, a configuration including any of a bipolar transistor element, a lateral MOS transistor element, and a complementary MOS transistor element can be adopted. In addition to the above, a diode, a capacitor, a resistor, a wiring, or the like can be adopted as the single-sided electrode element.

  According to a seventh aspect of the present invention, the plurality of double-sided electrode elements may include at least one double-sided electrode element having electrodes that are electrically separated from the electrodes in the other double-sided electrode elements. According to this, at least one double-sided electrode element can be configured to be multi-channeled (multi-channeled) that can be driven independently from the other double-sided electrode elements.

  As the isolation trench, as described in claim 8, an isolation trench in which an insulator is embedded in the trench, an isolation trench in which a conductor is embedded in the trench through a sidewall oxide film, and Any insulating isolation trench in which a cavity is formed in the trench can be employed.

  According to a ninth aspect of the present invention, the semiconductor substrate may be configured such that passive elements are formed as elements at connection portions that connect thickness regions having different thicknesses. As described above, when a passive element such as a capacitor or a resistor is formed at the connection portion, the size of the semiconductor device can be reduced.

  As described in claim 10, the semiconductor substrate may be a wafer. According to this, it is possible to obtain a semiconductor device in which elements are integrated according to element characteristics in a plurality of thickness regions formed on a wafer-like semiconductor substrate. Further, the mechanical strength of the wafer-like semiconductor substrate can be improved. That is, it is possible to suppress cracks that occur during conveyance or dicing.

  According to an eleventh aspect, the semiconductor substrate may be configured as a chip. According to this, it is possible to obtain a semiconductor device in which elements are integrated according to element characteristics in a plurality of thickness regions formed on a chip-shaped semiconductor substrate. Further, the mechanical strength of the semiconductor substrate formed into a chip can be improved.

  The plurality of thickness regions are formed in an annular shape so that the thick region surrounds a region having a smaller thickness than the region, and the thickness region on the outer peripheral side of the semiconductor substrate is formed. It is good also as the structure made into thickness so much. In a semiconductor substrate formed into chips after dicing, cracks are likely to occur from the end of the semiconductor substrate. Therefore, with the above configuration, in the semiconductor substrate that has been diced after dicing, the chip can be made less likely to crack. In addition, since the thickest region is provided in an annular shape on the outermost periphery, it is possible to improve the mountability of the semiconductor substrate formed into a chip.

  According to a thirteenth aspect of the present invention, the semiconductor substrate has a concave portion with respect to the surface of the thickest region on the thinner region than the thickest region, and is a member different from the semiconductor substrate. However, it is good also as a structure accommodated in the recessed part and mounted on the surface of the thin area | region which makes the bottom face of a recessed part.

  According to this, since the recess is used as a space for disposing a member different from the above-described semiconductor substrate, the size of the semiconductor device including the above-described semiconductor substrate and a member different from the semiconductor substrate is reduced. be able to. In addition, as a member different from the semiconductor substrate, at least one of a semiconductor chip, a wiring substrate, and a heat sink can be employed as described in claim 14.

  According to a fifteenth aspect of the present invention, a chip-shaped semiconductor substrate may have a plurality of thickness regions and a cavity that penetrates from the main surface to the back surface. Even in such a configuration having a hollow portion, the semiconductor substrate has a plurality of thickness regions as described above, so that the mechanical strength of the semiconductor substrate can be improved and cracking can be suppressed.

  With such a cavity, for example, as described in claim 16, the semiconductor substrate is disposed on the circuit board, and a part of the electrode on the back surface side of the circuit board mounting surface of the semiconductor substrate is on the outer peripheral side of the semiconductor substrate. The wire is electrically connected to the corresponding land of the circuit board by a wire, and a part of the electrode can be electrically connected to the corresponding land of the circuit board by a wire through the cavity. In this case, since the wire can be drawn not only to the outer peripheral side but also to the cavity side, the semiconductor substrate has many electrodes to be electrically connected to the circuit board on the back side of the circuit board mounting surface. However, it is easy to form an electrical connection structure with the circuit board.

  In addition, as described in claim 17, the semiconductor substrate is mounted on the sensor chip, and in the direction substantially perpendicular to the thickness direction of the semiconductor substrate, the sensing portion of the sensor chip is located in the cavity of the semiconductor substrate, A configuration surrounded by a semiconductor substrate can also be adopted. In this case, the semiconductor substrate functions as a circuit board of the sensor chip, and the sensing part of the sensor chip senses through the cavity of the semiconductor substrate. Therefore, the sensing area of the sensing unit can be limited by the semiconductor substrate.

  Next, an invention according to claim 18 is a method of manufacturing a semiconductor device in which a plurality of element formation regions are insulated from each other by an isolation trench formed in a semiconductor substrate, and an element is formed in each element formation region. Then, the semiconductor substrate is selectively etched from at least one of the main surface and the back surface to form a plurality of thickness regions, and a pair of electrodes is formed in the element formation region in the thinnest region. After forming an element in an element forming region of at least two thickness regions including the thinnest region so as to form a double-sided electrode element arranged separately on the main surface and the back surface of each element, The semiconductor substrate is diced to form a chip so that the thickness region in which is formed remains integrally.

  As described above, according to the present invention, it is possible to form the semiconductor device including the semiconductor substrate formed into a chip. In addition, since the wafer-like semiconductor substrate has a plurality of thickness regions, it is possible to suppress cracking of the semiconductor substrate during transportation or element formation. Further, since the dicing is performed so that the thickness region where the elements are formed remains integrally, it is possible to suppress cracks that occur during dicing. Furthermore, since the semiconductor substrate formed into a chip includes at least two thickness regions including the thinnest region, the mechanical strength of the semiconductor substrate formed into a chip can be improved.

  The element may be formed in a region excluding the thickest region, and the thickest region and a connecting portion between the region and another region may be removed by dicing. good. In this way, no element is formed in the thickest region, and dedicated to ensuring the mechanical strength until the chip is formed, the mechanical strength of the semiconductor substrate until the chip can be further improved. it can.

  According to the twentieth aspect, a plurality of thickness regions may be formed in the semiconductor substrate by etching, and a hollow portion penetrating from the main surface to the back surface of the semiconductor substrate may be formed. Since the function and effect are the same as the function and effect of the semiconductor device having the cavity described above, description thereof is omitted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a plan view showing a schematic configuration of the semiconductor device according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. Note that FIG. 1 shows only a part of a plurality of element formation regions that are insulated and separated. In FIG. 2, for convenience, a part of an impurity region in which an impurity is introduced into the semiconductor substrate 10 is omitted. Moreover, since a well-known element can be adopted as an element configured on the semiconductor substrate, the details of the element structure are omitted.

  In the semiconductor device 1 shown in FIGS. 1 and 2, an n-conductivity (n−) bulk single crystal silicon substrate is employed as the semiconductor substrate 10, and the semiconductor substrate 10 is diced into a chip. The semiconductor substrate 10 has a plurality of thickness regions (in the present embodiment, two thickness regions 11 and 12) having different thicknesses. As shown in FIG. The thick region 11 having a large thickness is a thin region 12 having a smaller thickness than the thick region 11 (in this embodiment, the thin region 12 having the thinnest thickness among the two thickness regions 11 and 12). Is formed in an annular shape so as to surround the semiconductor substrate 10, and the thickness region on the outer peripheral side of the semiconductor substrate 10 is thicker. The thin region 12 is made thinner than the thick region 11 by performing anisotropic etching on the semiconductor substrate 10 from the back surface 10b side of the main surface 10a, and the thick region 11 and the thin region 12 are connected. The etching surface of the connecting portion 13 to be tapered is tapered as shown in FIG. The semiconductor substrate 10 has a plurality of element formation regions 30 that are insulated and separated from each other, and an element 50 is configured using each element formation region 30 in the semiconductor substrate 10.

  The plurality of element forming regions 30 are partitioned (insulated and separated from each other) by insulating isolation trenches 31 penetrating from the main surface 10a of the semiconductor substrate 10 to the back surface 10b so as to surround each element forming region 30. In the present embodiment, the insulating isolation trench 31 is configured as an insulating isolation trench in which an insulator such as silicon oxide is embedded in a trench formed penetrating from the main surface 10a of the semiconductor substrate 10 to its back surface 10b. ing. The element forming region 30 is formed in each of the plurality of thickness regions 11 and 12 formed in the semiconductor substrate 10.

  The element 50 is configured using the semiconductor substrate 10 in each element forming region 30. That is, the element 50 is configured in each of the plurality of thickness regions 11 and 12. In the thick region 11, as a device 50, a single-sided electrode device is formed in which paired electrodes (electrodes through which current flows from one side to the other) are collectively arranged on the main surface 10 a side of the semiconductor substrate 10. . In other words, the single-sided electrode element is formed so that current flows in a direction perpendicular to the thickness direction of the semiconductor substrate 10. In FIG. 1, as a single-sided electrode element, a drain electrode 51a, a source electrode 51b, and a gate electrode 51c are formed on the main surface 10a side of the semiconductor substrate 10, and a driving current (drain) from the drain electrode 51a to the source electrode 51b is formed. A horizontal MOS transistor element 51 (LDMOS element) configured to flow current is shown. In the thin region 12, there is a double-sided electrode element in which a pair of electrodes (electrodes through which a current flows from one side to the other) are separately arranged on the main surface 10 a and the back surface 10 b of the semiconductor substrate 10 as the element 50. Is formed. In other words, the double-sided electrode element is formed so that a current flows in the thickness direction of the semiconductor substrate 10. In FIG. 1, vertical MOS transistor elements 52 (vertical DMOS elements), up-drain vertical MOS transistor elements 53, and wirings 54 are shown as double-sided electrode elements. The vertical MOS transistor element 52 includes a drain electrode 52a, a source electrode 52b, and a gate electrode 52c, and the drain electrode 52a and the source electrode 52b are separately formed on the main surface 10a and the back surface 10b of the semiconductor substrate 10. Yes. That is, the drive current (drain current) flows from the drain electrode 52a toward the source electrode 52b (in the thickness direction of the semiconductor substrate 10). Further, the up-drain vertical MOS transistor element 53 is formed on the drain electrode 53 a, source electrode 53 b, and gate electrode 53 c formed on the main surface 10 a side of the semiconductor substrate 10, and on the back surface 10 b side of the semiconductor substrate 10. And a back surface electrode 53d. The drain electrode 53a and the back electrode 53d are electrically connected via a wiring portion 53e in which a conductor is embedded in the trench via a sidewall oxide film. That is, the drive current (drain current) flows from the drain electrode 53a to the source electrode 53b via the wiring portion 53e and the back surface electrode 53d. Also in this configuration, the drive current flows from the drain electrode 53a to the back electrode 53d and from the back electrode 53d to the source electrode 53b, so that a current flows in the thickness direction of the semiconductor substrate 10. Further, the wiring 54 is electrically connected to the electrodes 54a and 54b formed on the main surface 10a and the back surface 10b of the semiconductor substrate 10 by a wiring portion 54c in which a conductor is embedded in the trench through a sidewall oxide film. It is the structure connected to. Of the elements 50 described above, the vertical MOS transistor element 52 and the up-drain vertical MOS transistor element 53 which are double-sided electrode elements are electrically separated from each other (electrically separated). Can be driven independently).

  In the present embodiment, as shown in FIG. 2, the connection portion 13 between the thick region 11 and the thin region 12 in the semiconductor substrate 10 is electrically connected to the thick region 11 and the thin region 12 by the insulating isolation trench 31. A passive element 55 such as a capacitor or a resistor is formed on the connecting portion 13 (tapered surface) on the back surface 10b side. A passive element 55 such as a capacitor or a resistor can also be formed on the tapered connecting portion 13. Thus, if the passive element 55 is formed in the connection part 13 of the plurality of thickness regions 11 and 12, the size of the semiconductor device 1 can be reduced. In the present embodiment, as shown in FIG. 2, the insulating isolation trench 31 for electrically insulating the connecting portion 13 from the thick region 11 and the thin region 12 is provided in the thick region 11 and the thin region 12. Is formed. Although the insulating isolation trench 31 for electrically insulating the connecting portion 13 from the thick region 11 and the thin region 12 can be formed in the connecting portion 13, as shown in FIG. When formed in the region 12, when forming the plurality of thickness regions 11, 12, the length of the insulating isolation trench 31 exposed on the back surface 10 b side is substantially equal, and the exposed portion can be easily removed. it can.

  Next, an example of a method for manufacturing the semiconductor device 1 will be described with reference to FIGS. FIG. 3 is a cross-sectional view showing a process of forming a non-penetrating insulating isolation trench in a semiconductor substrate among the processes of manufacturing a semiconductor device. FIG. 4 is a cross-sectional view showing a process of making the insulating isolation trench pass through in the process of manufacturing the semiconductor device. FIG. 5 is a cross-sectional view showing a step of forming a plurality of thickness regions on a semiconductor substrate among the steps of manufacturing a semiconductor device. As a method for manufacturing such a semiconductor device 1, the method described in Japanese Patent Application Laid-Open No. 20068-166705 and Japanese Patent Application No. 2008-106014 by the present applicant is applied except for the step of forming a plurality of thickness regions. be able to. Therefore, in the following, detailed description of overlapping parts is omitted.

  First, a semiconductor substrate 14 (semiconductor wafer) having a predetermined thickness (for example, 600 μm) is prepared. In the present embodiment, an n conductivity type (n−) single crystal bulk silicon substrate (FZ wafer) is prepared as the semiconductor substrate 14. Then, as shown in FIG. 3, it does not penetrate from the main surface 10a (corresponding to the main surface of the semiconductor substrate 10 after dicing) side to the back surface 10b of the semiconductor substrate 14 so as to surround each region to be the element forming region 30. In this way, the insulating isolation trench 31a having a predetermined depth is formed. This insulating isolation trench 31a is in a non-penetrating state. In this embodiment, as the isolation trench 31a, a trench having a predetermined depth is formed by, for example, anisotropic dry etching, and an isolation trench in which an insulator such as silicon oxide is embedded in the trench is employed. Yes. Further, the depth and width of the plurality of insulating isolation trenches 31a are substantially uniform.

  Next, as shown in FIG. 4, the semiconductor substrate 10 is removed from the back surface 10 b side until at least the end portion of the insulating isolation trench 31 a on the back surface 10 b side of the semiconductor substrate 10 is exposed. In other words, the thickness of the semiconductor substrate 14 is reduced from the back surface 10b side. As this thinning treatment, mechanical polishing, etching, or the like can be employed. In this embodiment, first, mechanical polishing is performed, and the polished surface is wet-etched in order to remove a damaged layer due to polishing after polishing. Thereby, the thickness of the wafer-like semiconductor substrate 14 becomes substantially the same as that of the thick region 11 in the semiconductor substrate 10 after dicing. Further, the non-penetrating insulating isolation trench 31a becomes the insulating isolation trench 31 penetrating from the main surface 10a to the back surface 10b. In other words, the element formation regions 30 are insulatively separated from each other.

  Next, as shown in FIG. 5, the semiconductor substrate 14 is selectively etched from the back surface 10 b side to form a plurality of thickness regions 11 and 12 in the semiconductor substrate 14. The etching method is not particularly limited, but wet or dry anisotropic etching is preferably employed. In this embodiment, by performing anisotropic wet etching using an aqueous KOH solution, the semiconductor substrate 14 is partially removed from the back surface 10b side, and the semiconductor substrate 14 is etched with the thick region 11 that is not etched. And the thinned region 12 that has become thin. As a result, each semiconductor substrate 10 (chip) after dicing the semiconductor substrate 14 also includes a plurality of thickness regions 11 and 12 connected by the tapered connecting portion 13.

  In the anisotropic wet etching, the semiconductor substrate 14 made of silicon is removed, but as shown by a two-dot chain line in FIG. 5, an insulating isolation trench is formed in the region where the semiconductor substrate 14 is removed. The insulator (silicon oxide) in the trench is hardly etched and remains as a columnar body 31b protruding from the back surface 10b of the thin region 12. Therefore, in this embodiment, the columnar body 31b is removed by HF treatment or the like after wet etching. Thereby, the columnar body 31b which protrudes from the back surface 10b of the thin area | region 12 is removed.

  After the formation of the plurality of thickness regions 11 and 12, elements 50 are formed in the element formation regions 30 of the semiconductor substrate 14 as shown in FIG. In the present embodiment, first, from the main surface 10 a side of the semiconductor substrate 14, a single-sided electrode element such as a horizontal MOS transistor element 51, a double-sided MOS transistor element 52, an up-drain MOS transistor element 53, a wiring 54, etc. The main surface 10a side portion of the electrode element is formed by ion implantation or the like. Next, the back surface 10b side portion of the double-sided electrode elements such as the vertical MOS transistor element 52, the up drain MOS transistor element 53, and the wiring 54 is formed from the back surface 10b side of the semiconductor substrate 14 by ion implantation or the like. And the semiconductor device 1 provided with the thick area | region 11 and the thin area | region 12 as the semiconductor substrate 10 can be obtained by dicing the semiconductor substrate 14 in the part which is not shown in the thick area | region 11. FIG.

  As described above, in the semiconductor device 1 according to the present embodiment, a plurality of thickness regions 11 and 12 having different thicknesses are formed on one chip semiconductor substrate 10 and at least two thicknesses are formed. Element formation regions 30 (elements 50) are formed in the regions 11 and 12, respectively. Therefore, each element 50 can be formed by being distributed to the thickness regions 11 and 12 having a thickness suitable for the characteristics of each element 50 (51 to 54) such as withstand voltage and on-resistance. In addition, the double-sided electrode elements (52 to 54) are formed in at least the thinnest region 12 among the at least two thickness regions 11 and 12 in which the element formation region 30 is formed. Therefore, in a configuration including at least double-sided electrode elements as the plurality of elements 50, current can easily flow between electrodes forming a pair of double-sided electrode elements. From the above, in a configuration in which a plurality of elements 50 including at least double-sided electrode elements (52 to 54) are formed on one semiconductor substrate 10, a semiconductor device 1 in which a plurality of elements 50 having different element characteristics are integrated. Yes. In the present embodiment, a semiconductor device (composite IC) in which a double-sided electrode element and a single-sided electrode element are integrated on one semiconductor substrate 10 is provided.

  In the present embodiment, the vertical MOS transistor element 52 (including the up-drain type MOS transistor element 53) is formed in the thin region 12 as the double-sided electrode element. It is possible to reduce the on-resistance of the drain type MOS transistor element 53).

  Further, the on-resistance of the double-sided electrode element can be lowered as the thickness of the semiconductor substrate 10 formed into a chip is thinner. However, if the entire thickness of the semiconductor substrate 10 is made uniform with the thickness of the thinnest region 12 where the double-sided electrode elements are formed, the mechanical strength is insufficient, and cracking occurs during dicing or conveyance after dicing. May occur. Further, if the mechanical strength is to be ensured, the semiconductor substrate 10 becomes thick and it becomes difficult to lower the on-resistance to a desired value. On the other hand, in the present embodiment, the semiconductor substrate 10 has not only the thinnest region 12 having the thinnest thickness but also the thick region 11 having a larger thickness, so that the mechanical strength of the semiconductor substrate 10 is improved. Has been.

  Further, in the semiconductor substrate 10 formed into chips after dicing, cracks are likely to occur from the end portions of the semiconductor substrate 10. On the other hand, in the present embodiment, the thick region 11 is formed in an annular shape so as to surround the thin region 12 that is thinner than the region 11, and the thicker region on the outer peripheral side of the semiconductor substrate 10 is thicker. It is said. Therefore, the semiconductor substrate 10 formed into a chip after dicing is less likely to be cracked. Further, since the thick region 11 is provided in an annular shape on the outermost periphery, the mountability when mounting the semiconductor substrate 10 formed as a chip on a circuit substrate (not shown) is improved.

  In the present embodiment, a single crystal bulk silicon substrate is used as the semiconductor substrates 10 and 14, and an insulating isolation trench 31 is formed in the substrate, thereby insulating a plurality of element formation regions 30 (elements 50) from each other. It is separated. Therefore, it is suitable for forming a double-sided electrode element such as the vertical MOS transistor element 52. In addition, it is easy to increase the resistance of double-sided electrode elements against surges such as an increase in current and ESD. Further, since the buried insulating film is not provided unlike the SOI substrate, the heat dissipation can be improved as compared with the configuration employing the SOI substrate.

  In the present embodiment, by forming the isolation trench 31 in the semiconductor substrate 10, the plurality of element formation regions 30 (elements 50) are insulated from each other and the vertical MOS transistor element 52 which is a double-sided electrode element. The electrodes forming a pair of the up-drain type vertical MOS transistor elements 53 are electrically separated from each other (can be driven independently). Therefore, the multi-channel semiconductor device 1 is obtained. However, for example, the electrode on the back surface 10b side of the semiconductor substrate 10 may be configured in common.

  In the present embodiment, examples of the vertical MOS transistor element 52 (vertical DMOS element), the up-drain vertical MOS transistor element 53, and the wiring 54 are shown as the double-sided electrode elements. However, an IGBT element can also be adopted as a power element other than the vertical MOS transistor element 52 (including the up drain vertical MOS transistor element 53). Further, as an active element, not only a vertical MOS transistor element and an IGBT element but also a diode element can be adopted. In addition to the wiring 54, a resistor or the like can be employed as the passive element. In the drawing, as an example of the wiring 54, an example including the wiring part 54 c in which a conductor is embedded in the trench through a sidewall oxide film is shown, but a wiring that does not have the wiring part 54 c is adopted. You can also

  In the present embodiment, an example of the lateral MOS transistor element 51 (LDMOS element) is shown as the single-sided electrode element. However, the single-sided electrode element may include any of a bipolar transistor element, a lateral MOS transistor element, and a complementary MOS transistor element. With such a configuration, a composite IC (control circuit) can be formed together with a vertical MOS transistor element, IGBT element, etc. employed as a double-sided electrode element. In addition to the above active element, a diode element that is an active element, a capacitor that is a passive element, a resistor, a wiring, or the like may be employed.

  Moreover, in this embodiment, the semiconductor substrate 10 (14) showed the example which has two thickness area | regions, the thick area | region 11 and the thin area | region 12, as a some thickness area | region. However, the number of thickness regions is not limited to the above example. Moreover, although the single-sided electrode element was formed in the thick area | region 11 and the double-sided electrode element was formed in the thin area | region 12 was shown, as a structure by which the double-sided electrode element was formed in the thick area 11 with the single-sided electrode element, A single-sided electrode element may be formed in the thin region 12 together with the double-sided electrode element. One semiconductor substrate 10 (14) has a plurality of thickness regions having different thicknesses, and element formation regions 30 (devices 50) are formed in at least two of the plurality of thickness regions. ing. And what is necessary is just the structure by which the double-sided electrode element was formed in the thin area | region with the thinnest thickness at least.

  In the present embodiment, the thin region 12 is made thinner than the thick region 11 by performing anisotropic etching on the semiconductor substrate 10 (14) from the back surface 10b side, and the semiconductor substrate 10 (14). Each of the electrodes 51a to 51c of the horizontal MOS transistor element 51, the source electrode 52b and the gate electrode 52c of the vertical MOS transistor element 52, and the like are formed on the main surface 10a side, and the vertical type is formed on the back surface 10b side of the thin region 12. The example in which the drain electrode 52a of the MOS transistor element 52 and the like are formed is shown. That is, the example in which the concave portion is formed on the back surface 10b side of the semiconductor substrate 10 (14) is shown. However, for example, as shown in FIG. 6, by performing anisotropic etching on the semiconductor substrate 10 (14) from the main surface 10a side, the thin region 12 is made thinner than the thick region 11, and on the main surface 10a side. The electrodes 51a to 51c of the horizontal MOS transistor element 51, the source electrode 52b and the gate electrode 52c of the vertical MOS transistor element 52, and the like are formed, and the drain electrode 52a of the vertical MOS transistor element 52 and the like are formed on the back surface 10b side. It is good also as a composition. That is, a configuration opposite to the configuration shown in the present embodiment (see FIG. 2), in other words, a configuration in which the concave portion is formed on the main surface 10a side of the semiconductor substrate 10 (14) may be employed. In this case, after forming the plurality of thickness regions 11 and 12, a portion of each element 50 on the main surface 10 a side of the semiconductor substrate 14 is formed. FIG. 6 is a cross-sectional view showing a modification. Further, the semiconductor substrate 10 (14) having the thick region 11 and the thin region 12 may be formed by performing anisotropic etching on the semiconductor substrate 10 (14) from both surfaces 10a and 10b. That is, it is good also as a structure by which the recessed part was formed in both surfaces 10a and 10b of the semiconductor substrate 10 (14), respectively. In this case, both surfaces 10a... In the direction perpendicular to the thickness direction of the semiconductor substrate 10 (14). When at least a part of the concave portions provided in 10b overlap each other, the thickness of the thin region 12 in the overlapping portion can be further reduced.

  Further, in the present embodiment, an example of the semiconductor device 1 including one semiconductor substrate 10 formed into a chip is shown. However, for example, as shown in FIG. 7, a similar configuration can be applied to a semiconductor device 70 including a semiconductor substrate 14 in a wafer state before dicing. In FIG. 7, a plurality of thickness regions 11 and 12 having different thicknesses are formed on a semiconductor substrate 14 in a wafer state, and an element formation region 30 (element 50) is formed in each of the thickness regions 11 and 12, respectively. ing. Moreover, the double-sided electrode elements (52 to 54) are formed in at least the thinnest region 12 among the plurality of thickness regions 11 and 12. Also in the semiconductor device 70 having such a configuration, the same effect as the semiconductor device 1 described above (the semiconductor device 70 in which a plurality of elements 50 having different element characteristics are integrated and the mechanical strength of the semiconductor substrate 14 is improved) Can be expected. FIG. 7 is a cross-sectional view showing a modification. Note that if the entire semiconductor substrate 14 in the wafer state is the thin region 12, cracks or the like are more likely to occur than the semiconductor substrate 10 that is made into chips due to its size. In particular, cracks are likely to occur during dicing. Therefore, in the semiconductor device 70 including the semiconductor substrate 14, the effect of improving the mechanical strength of the semiconductor substrate can be expected more than in the semiconductor device 1 including the semiconductor substrate 10.

  In the present embodiment, in forming the semiconductor device 1, the insulating isolation trench 31 is formed in the semiconductor substrate 14 from the main surface 10 a side, then the plurality of thickness regions 11 and 12 are formed, and then each element 50 is formed. The example which forms from the main surface 10a and the back surface 10b of the semiconductor substrate 14 was shown. However, before the formation of the plurality of thickness regions 11 and 12 and after the formation of the insulating isolation trench 31 or before the formation of the insulating isolation trench 31, the site on the main surface 10 a side of the semiconductor substrate 14 in each element 50 is changed. It can also be formed. Also, before forming the plurality of thickness regions 11 and 12, p-type impurities are partially ion-implanted from the back surface 10b side of the semiconductor substrate 10, and the interface of the pn junction is used as an etching stopper. May be. Further, by forming the semiconductor substrate 10 by the silicon substrate (n) and the epitaxial layer (p) having a different conductivity type, the interface between the substrate and the epitaxial layer (pn junction) is used as an etching stopper. Anyway.

  Further, as shown in FIG. 8, after forming a plurality of thickness regions 11 and 12 on the semiconductor substrate 14, for example, an interlayer insulating film such as a BPSG film (not shown) formed on the surface 14 of the semiconductor substrate 14 or a LOCOS oxidation film. As shown in FIG. 9, an insulating isolation trench 31 may be formed in the semiconductor substrate 14 from the back surface 10b side using a film or the like as a stopper. According to this method, in order to expose the end of the insulating isolation trench 31 on the back surface 10b side, it is possible to eliminate the process of thinning the semiconductor substrate 14. Further, even when the semiconductor substrate 14 is thinned, the thinning is performed before the plurality of thickness regions 11 and 12 are formed on the semiconductor substrate 14, so that it is not necessary to remove the columnar body 31 b. . 8 and 9 are cross-sectional views showing a modification of the method for manufacturing a semiconductor device according to the present embodiment, and FIG. 8 shows a step of forming a plurality of thickness regions on the semiconductor substrate in the manufacturing steps. FIG. 9 shows a step of forming an insulating isolation trench. 8 and 9, the element 50 is omitted for convenience.

  In this embodiment, the semiconductor device 1 including the thick region 11 and the thin region 12 is formed as the semiconductor substrate 10 by dicing the semiconductor substrate 14 at a part (not shown) in the thick region 11. showed that. However, as the thickness region, for example, as shown in FIG. 10, the thick region 11 and the thin region 12 are thicker than the thick region 11 and the region 15 where the element 50 is not formed (the thickest region 15). Formed and diced along a scribe line 71 indicated by a two-dot chain line in FIG. 10, the thickest region 15, and the region 15 and other regions (thick wall region 11 in the example shown in FIG. 10). The semiconductor device 1 including the thick region 11 and the thin region 12 may be formed as the semiconductor substrate 10. As described above, by providing the thickest region 15 dedicated to securing the mechanical strength until the semiconductor substrate 14 is chipped, the mechanical strength of the semiconductor substrate 14 until it is chipped can be further improved. . FIG. 10 is a cross-sectional view showing a modification of the semiconductor substrate in the wafer state.

  Further, in the present embodiment, an example of an insulating isolation trench in which an insulator is embedded in the trench is shown as the insulating isolation trench 31. However, other than that, an insulating isolation trench in which a conductor is embedded in the trench through a sidewall oxide film, or an insulating isolation trench in which a cavity is formed without an insulator being embedded in the trench is adopted. You can also

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 11 is a cross-sectional view showing a schematic configuration of the semiconductor device according to the second embodiment, and corresponds to FIG. 2 shown in the first embodiment.

  Since the semiconductor device according to the second embodiment is often in common with the semiconductor device according to the first embodiment, the detailed description of the common parts will be omitted below, and different parts will be mainly described. In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

  In the first embodiment, the semiconductor substrate 10 has two thickness regions, a thick region 11 and a thin region 12, a single-sided electrode element is formed in the thick region 11, and a double-sided electrode element is formed in the thin region 12. An example to be shown. On the other hand, the present embodiment is characterized in that double-sided electrode elements are formed in a plurality of thickness regions in which the semiconductor substrate 10 is configured.

  In the example shown in FIG. 11, the semiconductor substrate 10 has two thickness regions, a thick region 11 and a thin region 12, which are different in thickness from each other, as in the first embodiment. Using the thickness of the semiconductor substrate 10 in the region 11, for example, an IGBT element 56 having a withstand voltage of 1000 V is formed. Further, an IGBT element 57 having a lower withstand voltage (for example, withstand voltage of 500 V) than the IGBT element 56 is formed in the thin area 12 using the thickness of the semiconductor substrate 10 in the thin area 12. The IGBT elements 56 and 57 have collector electrodes 56a and 57a formed on the back surface 10b side of the semiconductor substrate 10, respectively, and emitter electrodes 56b and 57b and gate electrodes 56c and 57c on the main surface 10a side of the semiconductor substrate 10, respectively. Is formed. The drive current flows from the collector electrodes 56a and 57a toward the emitter electrodes 56b and 57b (in the thickness direction of the semiconductor substrate 10).

  In the present embodiment, the isolation trench 31 is formed in the semiconductor substrate 10 to insulate and isolate the plurality of element formation regions 30 (elements 50) from each other, and the IGBT elements 56 and 57 that are double-sided electrode elements. The paired electrodes are electrically separated from each other (can be driven electrically independently). Therefore, also in this embodiment, the semiconductor device 1 is multi-channeled.

  As described above, according to the present embodiment, the IGBT elements 56 and 57 are formed in the two thickness regions 11 and 12 of the semiconductor substrate 10, respectively, so that the IGBT elements correspond to the thicknesses of the thickness regions 11 and 12. The withstand voltages of 56 and 57 can be different. Therefore, the semiconductor device 1 in which the IGBT elements 56 and 57 having different breakdown voltages are integrated on the same semiconductor substrate 10 can be obtained.

  In the present embodiment, the semiconductor substrate 10 has two thickness regions 11 and 12, and the IGBT elements 56 and 57 are formed in the thickness regions 11 and 12, respectively. However, the semiconductor substrate 10 may have three or more thickness regions, and the IGBT element may be formed in at least two regions including the thinnest region. For example, in the example shown in FIG. 12, the semiconductor substrate 10 has two thick regions 12 a and 12 b having different thicknesses as the thickest region 11 and the thinner region 12 than the thick region 11. It has a configuration. Of the three thickness regions 11, 12a and 12b, IGBT elements 58 and 59 are formed in the thinnest region 12a and the thinnest region 12b after the thinnest region 12a, respectively. The IGBT device 58 and 59 having different withstand voltages is integrated in the same semiconductor substrate 10. Further, in the semiconductor device 1 shown in FIG. 12, the element 50 is not formed in the thick region 11, and the thick region 11 performs only the function of ensuring the mechanical strength in the semiconductor substrate 10. . FIG. 12 is a cross-sectional view showing a modification. Also in the example shown in FIG. 12, the plurality of thickness regions 11, 12 a, and 12 b are formed in an annular shape so that the thicker region surrounds the thinner region than the region. The thickness region on the outer peripheral side is made thicker. As described above, the configuration in which the semiconductor substrate 10 has three or more thickness regions can be configured by performing etching in multiple stages in the manufacturing process shown in the first embodiment. In addition, by making the opening areas in the mask different during etching, different depths are applied to a plurality of different portions of the semiconductor substrate 10 to obtain different thickness regions. It is also possible to have three or more.

  12 shows a configuration in which the element 50 is not formed in the thick region 11, but, for example, in the configuration shown in FIG. 12, a configuration in which the element 50 is not formed in the thin region 12b after the thinnest region 12a. It can also be. In other words, the element 50 may not be formed in at least one thickness region excluding the thinnest region (thin region 12a in FIG. 12) among the plurality of thickness regions.

  Moreover, in this embodiment, the example in which a double-sided electrode element is formed only in two thickness area | regions 11 and 12 was shown. However, the double-sided electrode element may be formed in three or more thickness regions (for example, three thickness regions 11, 12a, and 12b shown in FIG. 12). For example, the semiconductor device 1 in which IGBT elements are respectively formed in three or more thickness regions, and three or more types of IGBT elements having different withstand voltages according to the thickness of the thickness regions are integrated on the same semiconductor substrate 10 You can also

  Moreover, in this embodiment, the example of the IGBT element was shown as a double-sided electrode element. However, the double-sided electrode element is not limited to the IGBT element. As shown in the first embodiment, a vertical MOS transistor element may be employed, or both a vertical MOS transistor element and an IGBT element may be employed. For example, as shown in FIG. 12, in the configuration in which the semiconductor substrate 10 has three thickness regions 11, 12a, and 12b, a vertical MOS transistor element is formed in the thinnest region 12a aiming at low on-resistance, An IGBT element may be formed in each of the thickness regions 11 and 12b. In addition, together with these, the semiconductor substrate 10 may be used to configure diode elements, resistors, wirings, and the like.

  Moreover, in this embodiment, the example which has only a double-sided electrode element (IGBT element) as the element 50 was shown. However, as shown in the first embodiment (see FIG. 2), the single-sided electrode element may be integrated with the double-sided electrode element. For example, in the configuration shown in FIG. 12, a single-sided electrode element such as a lateral MOS transistor element may be formed in the thick region 11. With such a configuration, the semiconductor device 1 can be a composite IC (control circuit).

  Further, in the present embodiment, an example of the semiconductor device 1 including one semiconductor substrate 10 formed into a chip is shown. However, as shown in the first embodiment (see FIG. 7), the same configuration can be applied to the semiconductor device 70 including the semiconductor substrate 14 in a wafer state before dicing.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 13 is a cross-sectional view illustrating a schematic configuration of a semiconductor device according to the third embodiment.

  Since the semiconductor device according to the third embodiment is often in common with the semiconductor device according to each of the above-described embodiments, a detailed description of the common parts will be omitted, and different parts will be mainly described below. In addition, the same code | symbol shall be provided to the element same as the element shown to said each embodiment.

  In the semiconductor device 1 described above, the region on the semiconductor substrate 10 that is thinner than the thickest region (for example, the thick region 11 shown in FIG. 2) (for example, the thin region 12 shown in FIG. 2) It will have a recessed part with respect to the surface of a thick area | region. Therefore, it is possible to adopt a configuration in which a member different from the semiconductor substrate 10 is accommodated in the concave portion and mounted on the surface of a thin region forming the bottom surface of the concave portion. When such a configuration is adopted, the recess is utilized as a space for disposing a member different from the semiconductor substrate 10, so that the physique of the semiconductor device 1 including the semiconductor substrate 10 and a member different from the semiconductor substrate 10 is provided. It can be downsized.

  In the example shown in FIG. 13, a chip-shaped semiconductor substrate 10 has a thick region 11 and a thin region 12, and a single-sided electrode element (a lateral MOS transistor device 60 is illustrated in FIG. 13) is formed in the thick region 11. The semiconductor device 1 has a double-sided electrode element (IGBT element 61 is illustrated in FIG. 13) formed in the thin region 12. The adhesive member 110 is interposed between one surface of the circuit board 90 and the thick region 11 on the back surface 10 b of the semiconductor substrate 10, so that the semiconductor device 1 is fixed to the circuit board 90. Further, in this fixed state, a rewiring board 130 (corresponding to the wiring board described in the claims) is accommodated in the recess formed on the back surface 10 b of the thin area 12, and is formed on the thin area 12. Has been implemented. The land 131 formed on the surface on the back surface 10b side of the substrate 130 is electrically connected to the collector electrode 61b of the IGBT element 61 formed in the thin region 12 via a connection member 150 such as solder. . Further, the land 132 formed on the surface of the substrate 130 on the circuit board 90 side is electrically connected to the land 91 formed on the bonding surface of the semiconductor device 1 on the circuit board 90 via a connecting member 150 such as solder. Has been.

  When such a structure is employed, the size of the semiconductor device 1 including the substrate 130 can be reduced as a member different from the semiconductor substrate 10. Further, the electrode on the back surface 10b side of the double-sided electrode element formed in the thin region 12 (IGBT in FIG. 13) while the surface (the back surface 10b in FIG. The collector electrode 61 b) of the element 61 can be electrically connected to the land 91 (wiring) of the circuit board 90.

  The member accommodated in the recess of the semiconductor substrate 10 is not limited to the substrate 130. In the example shown in FIG. 14, the semiconductor device 1 having almost the same configuration as that in FIG. 13 is employed. The difference is that the collector electrode 61b of the IGBT element 61 formed on the back surface 10b of the semiconductor substrate 10 is extended to the thick part via the tapered connecting part 13 respectively. In the thick portion 11, the collector electrode 61 b is electrically connected to a land 91 formed on the bonding surface of the semiconductor device 1 in the circuit board 90 via a connection member 150 such as solder. Further, in this fixed state, a heat sink 170 is disposed in a recess formed on the back surface 10 b of the thin region 12, and the heat sink 170 is a part of the thin region 12 on the back surface 10 b of the semiconductor substrate 10 via the insulating member 171. It is fixed to (collector electrode 61b).

  Even if such a structure is adopted, the size of the semiconductor device 1 including the heat sink 170 as a member different from the semiconductor substrate 10 can be reduced. Further, the electrode on the back surface 10b side of the double-sided electrode element formed in the thin region 12 (IGBT in FIG. 14) while the surface (the back surface 10b in FIG. The collector electrode 61 b) of the element 61 can be electrically connected to the land 91 (wiring) of the circuit board 90. Further, in the configuration in which the semiconductor device 1 is mounted on the circuit board 90, the rewiring board 130 is not necessary, and the heat sink 170 can be disposed in the vacant space. Therefore, as a double-sided electrode element formed in the thin region 12, FIG. In the configuration employing a power element such as the IGBT element 61 shown in FIG. FIG. 14 is a cross-sectional view showing a modification.

  Further, in the example shown in FIG. 15, the semiconductor device 1 having substantially the same configuration as that in FIG. 13 is employed. The difference is that an IC chip 190 different from the semiconductor substrate 10 is disposed in a recess formed on the back surface 10b of the thin region 12, and one of the electrodes 191 formed on the surface of the IC chip 190 on the back surface 10b side. The portion is electrically connected to the collector electrode 61b of the IGBT element 61 formed in the thin region 12 via a connection member 150 such as solder. In addition, a part of the electrode 191 is electrically separated from the collector electrode 61 b, and the wiring 62 formed on the thick region 11 from the thin region 12 through the connecting portion 13 on the back surface 10 b of the semiconductor substrate 10. Are electrically connected via a connecting member 150 such as solder. The wiring 62 is electrically connected to the land 91 formed on the bonding surface of the semiconductor device 1 in the circuit board 90 via the connection member 150 such as solder in the thick portion 11.

  Even if such a structure is employed, the size of the semiconductor device 1 including the IC chip 190 can be reduced as a member different from the semiconductor substrate 10. Further, the electrode on the back surface 10b side of the double-sided electrode element formed in the thin region 12 (IGBT in FIG. 15) while the surface (rear surface 10b in FIG. 13) of the semiconductor substrate 10 having the concave portion is the mounting surface of the circuit board 90. The collector electrode 61 b) of the element 61 can be electrically connected to the land 91 (wiring) of the circuit board 90 through the IC chip 190 and the wiring 62. FIG. 15 is a cross-sectional view showing a modification.

  13 to 15, as an example of the mounting structure of the semiconductor device 1, the semiconductor device 1 including another member together with the semiconductor substrate 10 is mounted on the circuit board 90. However, the mounting structure of the semiconductor device 1 is not limited to the above example. In the semiconductor device 1 including a member different from the semiconductor substrate 10, at least another member such as the substrate 130, the heat sink 170, and the IC chip 190 is accommodated in the concave portion of the semiconductor substrate 10 that is formed into a chip, and the bottom surface of the concave portion is formed. A structure in which another member is mounted on the surface of the thin region formed is preferable because the size of the semiconductor device 1 can be reduced as described above.

(Fourth embodiment)
Next, 4th Embodiment of this invention is described based on FIGS. FIG. 16 is a plan view illustrating a schematic configuration of the semiconductor device according to the fourth embodiment. In FIG. 16, only a part of a plurality of element forming regions that are insulated and separated is illustrated. 17 is a cross-sectional view taken along line XVII-XVII in FIG. In FIG. 17, for convenience, elements configured on the semiconductor substrate are omitted. 18 and 19 show a specific application example, and FIG. 18 is a cross-sectional view showing a state in which a semiconductor substrate having a cavity is mounted on a circuit board. FIG. 19 is a cross-sectional view showing a state where a semiconductor substrate having a cavity is mounted on a sensor chip. Also in FIGS. 18 and 19, elements formed on the semiconductor substrate are omitted.

  Since the semiconductor device according to the fourth embodiment is often in common with those according to the above-described embodiments, the detailed description of the common parts will be omitted below, and different parts will be described mainly. In addition, the same code | symbol shall be provided to the element same as the element shown to said each embodiment.

  In the above-described embodiment, an example of the semiconductor substrate 10 having a plurality of thickness regions is shown, and an example in which such a thickness region is formed by etching has been shown. Therefore, if this etching is utilized, a plurality of thickness regions can be formed in the semiconductor substrate 14 and the cavity 16 penetrating from the main surface 10a to the back surface 10b can be formed. That is, for example, as shown in FIGS. 16 and 17, the semiconductor substrate 10 has a plurality of thickness regions (thickness regions 11, 12a, and 12b in the examples shown in FIGS. 16 and 17) and the main surface 10a. It is also possible to have a structure having a cavity 16 penetrating from the back surface 10b to the back surface 10b. As described above, even when the semiconductor substrate 10 has the structure having the cavity 16, the semiconductor substrate 10 has a plurality of thickness regions (particularly, the thick region 11) as described above. Can be improved and cracking can be suppressed.

  For example, in the example shown in FIG. 18, the semiconductor substrate 10 is etched on the main surface 10a side to have a plurality of thickness regions 11 and 12 and a cavity portion 16, and the semiconductor substrate 10 has the back surface 10b as a mounting surface. Arranged on the circuit board 90. A part of the electrode 63 on the back surface (main surface 10 a) side of the circuit board mounting surface in the semiconductor substrate 10, specifically, the electrode 63 on the outer peripheral side of the semiconductor substrate 10 is a wire 64 on the outer peripheral side of the semiconductor substrate 10. Thus, the corresponding land 91 of the circuit board 90 is electrically connected. A part of the electrode 63, specifically, the electrode 63 on the side of the cavity 16 (inner peripheral side) is electrically connected to the corresponding land 91 of the circuit board 90 through the cavity 16 by the wire 64. ing. An electrode (not shown) on the circuit board mounting surface (the back surface 10b in FIG. 18) side of the semiconductor substrate 10 is electrically connected to the corresponding land 91 via a connection member 150 such as solder.

  As described above, when the cavity 16 is provided in the semiconductor substrate 10, the wire 64 can be drawn out not only on the outer peripheral side of the semiconductor substrate 10 but also on the cavity 16 side. Therefore, even if the semiconductor substrate 10 has many electrodes 63 on the back side of the circuit board mounting surface, it is easy to form an electrical connection structure with the circuit board 90.

  In the example shown in FIG. 19, the semiconductor substrate 10 having the same configuration as the semiconductor substrate 10 shown in FIG. 18 is mounted on the sensor chip 210 with the back surface 10 b as a mounting surface. It functions as a circuit board (processing circuit). Then, in a direction substantially perpendicular to the thickness direction of the semiconductor substrate 10, the sensing part 211 (the part surrounded by a two-dot chain line in FIG. 19) of the sensor chip 210 is located in the cavity 16 of the semiconductor substrate 10. The semiconductor substrate 10 is surrounded. Specifically, the open end of the cavity 16 on the sensor chip mounting surface (the back surface 10b in FIG. 19) of the semiconductor substrate 10 is substantially coincident with the sensing unit 211 in the substantially vertical direction described above.

  As described above, when the cavity 16 is provided in the semiconductor substrate 10, the sensing unit 211 of the sensor chip 210 can be sensed via the cavity 16 of the semiconductor substrate 10. That is, the sensing area of the sensing unit 211 can be limited by the semiconductor substrate 10. For example, when the sensing unit 211 includes a light detection element that generates an electrical signal corresponding to the intensity of incident light, the light incident on the sensing unit 211 is transmitted by the semiconductor substrate 10 on which the processing circuit of the sensor chip 210 is configured. Thus, it is possible to suppress detection accuracy degradation and detection variation due to disturbance light. Further, when the sensing unit 211 includes, for example, a laser generating element that generates a transmission wave, the emission direction of the laser light oscillated from the sensing unit 211 is limited by the semiconductor substrate 10 on which the processing circuit of the sensor chip 210 is configured. Can do.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The present invention includes a semiconductor substrate, an insulating isolation trench that surrounds each of the plurality of element formation regions in the semiconductor substrate and that insulates and isolates the plurality of element formation regions from each other, and each of the plurality of element formation regions A semiconductor device having a plurality of thickness regions having different thicknesses, and including at least two regions having the thinnest thickness among the plurality of thickness regions. There is no particular limitation as long as an element formation region is formed in one thickness region, includes at least a double-sided electrode element as an element, and the double-sided electrode element is formed at least in the thinnest region. For example, the type and number of elements 50 in each of the regions 11 and 12 (in other words, the number of element forming regions 30 partitioned by the insulating isolation trenches 31) are not limited to the above-described embodiments. Further, the form of each element 50 is not limited to the example of the embodiment described above. For example, although an example of an n-channel MOS transistor element or an IGBT element has been shown, a p-channel type can also be adopted. Moreover, a trench gate structure can also be adopted as these elements.

  In FIG. 10 in the present embodiment, the thick region 11 and the thin region 12 are formed together with a region 15 (the thickest region 15) where the element 50 is not formed, which is thicker than the thick region 11. By dicing along the scribe line 71 indicated by a two-dot chain line, the thickest region 15 and a connecting portion 13 between the region 15 and another region (thick region 11 in the example shown in FIG. 10). In this example, the semiconductor device 1 including the thick region 11 and the thin region 12 is formed as the semiconductor substrate 10. As described above, when the thickest region 15 dedicated to ensuring the mechanical strength until the semiconductor substrate 14 is chipped (referred to as the semiconductor substrate 10) is provided, the mechanical strength of the semiconductor substrate 14 until the chip is formed. Can be further improved. Such a technical idea is not limited to the formation of the semiconductor substrate 10 having a plurality of thickness regions and having elements formed in at least two thickness regions. For example, the semiconductor substrate 10 having a plurality of thickness regions, in which the element 50 is formed only in one thickness region, or having only one thickness region (in other words, the total thickness is It can also be applied to the formation of a substantially uniform semiconductor substrate 10. For example, in the example shown in FIG. 20, the semiconductor substrate 14 is provided with a thickest region 15 dedicated to ensuring mechanical strength and a thinned region 12 that is thinner than the region 15 by etching. Then, the semiconductor substrate 14 is diced along a scribe line 71 shown by a two-dot chain line in FIG. 20 (diced in the thin region 12), so that the semiconductor substrate 10 has only the thin region 12, and the region 12 It is also possible to obtain the semiconductor device 1 in which a plurality of element forming regions 30 surrounded by the insulating isolation trenches 31 are formed. According to this, a semiconductor device 1 is obtained in which a plurality of elements 50 including double-sided electrode elements are integrated on a semiconductor substrate 10 having a uniform thickness. Therefore, until the dicing, since the semiconductor substrate 14 has the thickest region 15 dedicated to ensuring the mechanical strength, the mechanical strength of the semiconductor substrate 14 having the thin region 12 can be improved. That is, it is possible to suppress cracks during transportation of the semiconductor substrate 14 and cracks during dicing. In addition, it is possible to facilitate the flow of current (lower on-resistance) between the electrodes forming a pair of double-sided electrode elements formed on the semiconductor substrate 10 while improving the mechanical strength. FIG. 20 is a cross-sectional view showing another modification.

1 is a plan view showing a schematic configuration of a semiconductor device according to a first embodiment. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing which shows the process of forming the non-penetrating insulation isolation trench in a semiconductor substrate among the processes which manufacture a semiconductor device. It is sectional drawing which shows the process of making an insulation isolation trench into a penetration state among the processes which manufacture a semiconductor device. It is sectional drawing which shows the process of forming a several thickness area | region in a semiconductor substrate among the processes of manufacturing a semiconductor device. It is sectional drawing which shows a modification. It is sectional drawing which shows a modification. It is sectional drawing which shows the modification of a manufacturing method, and has shown the process of forming a several thickness area | region in a semiconductor substrate among manufacturing processes. It is sectional drawing which shows the modification of a manufacturing method, and has shown the process of forming an insulation isolation trench among manufacturing processes. It is sectional drawing which shows the modification of the semiconductor substrate of a wafer state. It is sectional drawing which shows schematic structure of the semiconductor device which concerns on 2nd Embodiment. It is sectional drawing which shows a modification. It is sectional drawing which shows schematic structure of the semiconductor device which concerns on 3rd Embodiment. It is sectional drawing which shows a modification. It is sectional drawing which shows a modification. It is a top view which shows schematic structure of the semiconductor device which concerns on 4th Embodiment. It is sectional drawing which follows the XVII-XVII line of FIG. It is sectional drawing which shows the state which mounted the semiconductor substrate which has a cavity part in a circuit board. It is sectional drawing which shows the state which mounted the semiconductor substrate which has a cavity part in a sensor chip. It is sectional drawing which shows another modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Semiconductor device 10 ... Semiconductor substrate 11 ... Thick region 12 ... Thin region 30 ... Element formation region 31 ... Insulation isolation trench 50 ... Elements 51, 60 ... Horizontal MOS transistor element (single-sided electrode element)
52 ... Vertical MOS transistor element (double-sided electrode element)
56-59, 61 ... IGBT element (double-sided electrode element)

Claims (20)

A semiconductor substrate;
An insulation isolation trench that surrounds each of the plurality of element formation regions in the semiconductor substrate and that insulates and isolates the plurality of element formation regions from each other through the semiconductor substrate;
An element configured in each of the plurality of element formation regions, and a semiconductor device comprising:
The semiconductor substrate has a plurality of thickness regions having different thicknesses from each other,
The element formation regions are respectively formed in at least two of the plurality of thickness regions including the thinnest region,
The semiconductor includes a double-sided electrode element formed as an element in at least the thinnest region and having a pair of electrodes arranged separately on a main surface of the semiconductor substrate and a back surface of the main surface. apparatus.   The semiconductor device according to claim 1, wherein the double-sided electrode element includes any one of a vertical MOS transistor element and an IGBT element.   The semiconductor device according to claim 1, wherein the double-sided electrode element is formed in each of the plurality of thickness regions including the thinnest region. The element includes a single-sided electrode element in which a pair of electrodes are arranged together on the main surface of the semiconductor substrate,
4. The semiconductor device according to claim 3, wherein the single-sided electrode element is formed in at least one of the thickness regions different from the thickness region in which the double-sided electrode element is formed. As the element, together with the double-sided electrode element, includes a single-sided electrode element in which a pair of electrodes are arranged together on the main surface of the semiconductor substrate,
A plurality of the double-sided electrode elements are formed only in the thinnest region,
The semiconductor according to claim 1, wherein the single-sided electrode element is formed in at least one of the thickness regions different from the thickness region in which the double-sided electrode element is formed. apparatus.   6. The semiconductor device according to claim 4, wherein the single-sided electrode element includes any one of a bipolar transistor element, a lateral MOS transistor element, and a complementary MOS transistor element.   The plurality of double-sided electrode elements include at least one double-sided electrode element having electrodes that are electrically separated from electrodes in the other double-sided electrode elements. The semiconductor device according to item.   The isolation trench includes an isolation trench in which an insulator is embedded in the trench, an isolation trench in which a conductor is embedded in the trench through a sidewall oxide film, and a cavity is formed in the trench. The semiconductor device according to claim 1, wherein the semiconductor device is any one of insulating isolation trenches.   9. The passive element as claimed in claim 1, wherein a passive element is formed as the element at a connection portion of the semiconductor substrate that connects the thickness regions having different thicknesses. Semiconductor device.   The semiconductor device according to claim 1, wherein the semiconductor substrate is a wafer.   The semiconductor device according to claim 1, wherein the semiconductor substrate is formed into a chip.   The plurality of thickness regions are formed in an annular shape so that a thick region surrounds a region having a smaller thickness than the region, and the thickness region on the outer peripheral side of the semiconductor substrate is made thicker. The semiconductor device according to claim 11. The semiconductor substrate has a recess with respect to the surface of the thickest region on the thinnest region than the thickest region;
The member different from the semiconductor substrate is housed in the recess and mounted on the surface of the thin region forming the bottom surface of the recess. A semiconductor device according to 1.   14. The semiconductor device according to claim 13, wherein the member different from the semiconductor substrate is at least one of a semiconductor chip, a wiring board, and a heat sink.   The semiconductor device according to claim 11, wherein the semiconductor substrate has a cavity that penetrates from the main surface to the back surface together with the plurality of thickness regions. The semiconductor substrate is disposed on a circuit board;
A part of the electrode on the back side of the circuit board mounting surface of the semiconductor substrate is electrically connected to a corresponding land of the circuit board by a wire on the outer peripheral side of the semiconductor substrate, and a part thereof via the cavity The semiconductor device according to claim 15, wherein the semiconductor device is electrically connected to a corresponding land of the circuit board by a wire. The semiconductor substrate is mounted on a sensor chip,
16. The sensing part of the sensor chip is located in a cavity of the semiconductor substrate and is surrounded by the semiconductor substrate in a direction substantially perpendicular to the thickness direction of the semiconductor substrate. Semiconductor device. A method of manufacturing a semiconductor device, wherein a plurality of element formation regions are insulated and isolated from each other by an isolation trench formed in a semiconductor substrate, and an element is formed in each element formation region,
A plurality of thickness regions are formed by selectively etching the semiconductor substrate from at least one of the main surface and the back surface, and a pair of electrodes is formed in the element formation region in the thinnest region. After forming the element in the element formation region of at least two thickness regions including the thinnest region so as to form a double-sided electrode element arranged separately on the main surface and the back surface of the semiconductor substrate ,
A method of manufacturing a semiconductor device, wherein the semiconductor substrate is diced so that the thickness region in which the element is formed remains integrally in each chip. Forming the element in a region excluding the thickest region;
19. The semiconductor according to claim 18, wherein the dicing removes the thickest region and a connecting portion that connects the thickest region and a region having a different thickness from the thickest region. Device manufacturing method.   20. The plurality of thickness regions are formed in the semiconductor substrate by the etching, and a cavity that penetrates from the main surface to the back surface of the semiconductor substrate is formed. A method for manufacturing a semiconductor device.

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