JP2014104522A - Single-side processing method of wafer and production method of wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single-side processing method of a wafer capable of processing single sides of many wafers accurately by single processing in a both sides processing device.SOLUTION: The single-side processing method of a wafer comprises the steps of: preparing a carrier 10 of the wafer having plural concavities 11 whose diameter d is larger than that of the wafer and whose depth h is shallower than the thickness of the wafer on its vertical sides; attaching the wafer to the concavities 11 of the carrier 10 by using liquid; and performing lapping to a single-side of the wafer after setting of the carrier 10 to which the wafer has been attached to a both sides processing device.

Description

  The present invention relates to a method for processing a single side of a wafer and a method for manufacturing a wafer.

  Conventionally, for wafers of general materials such as silicon, depending on the type and application of the wafer, it may require different processing, such as different surface roughness between the front surface and the back surface, so one side of the wafer Only the polishing method has been studied.

  In Patent Document 1, the surfaces of two wafers subjected to hydrophilic treatment are adhered to each other so that the silicon wafers are bonded together, inserted into the wafer mounting hole of the carrier of the double-side polishing machine, fixed, and then bonded to each other. A single-side polishing method of a silicon wafer by a double-side polishing machine that polishes both sides located outside the wafer is disclosed.

  In Patent Document 2, two wafers to be processed on one side are attached to both sides of a jig, and each side of the two wafers is moved by relative movement between two rotary surface plates of a double-sided processing machine. A wafer processing method for processing simultaneously is disclosed.

  Patent Document 3 includes a wafer storage hole for storing and holding a semiconductor wafer to be polished on both sides, and the semiconductor wafer is stored and held in the wafer storage hole between the upper surface plate and the lower surface plate or a polishing cloth. In a semiconductor wafer carrier for a double-side polishing machine that is sandwiched between and revolved, the wafer storage hole is formed as a blind hole made of a recess shallower than the thickness of the semiconductor wafer. A carrier is disclosed.

JP 05-152263 A JP 59-044829 A JP 2005-32896 A

  However, the single-side polishing method described in Patent Document 1 requires high flatness in order to bond two wafers, and has a problem that it cannot be applied to a wafer with poor flatness before bonding. Further, when the flatness of the wafer is poor, there is a problem that even if the wafer can be bonded, polishing varies depending on the shape of the warp of the wafer and the processing accuracy is lowered. Further, in Patent Document 1, hydrophilic treatment is performed, but depending on the material of the wafer, the hydrophilic treatment cannot be performed, so that the types of applicable wafers are limited.

  The wafer processing method described in Patent Document 2 has a problem that a jig to be used is complicated, and it is necessary to frequently change pins due to wear due to processing, resulting in an increase in man-hours and sufficient cost merit. There was a problem that it was not possible.

  In the semiconductor wafer carrier for a double-side polishing machine described in Patent Document 3, the number of wafers that can be polished at one time is limited because the wafer storage hole is provided only on one side (upper surface) of the carrier. The efficiency was not good.

  In addition, since a resin carrier is used as the wafer carrier, processing accuracy (flatness) due to the wear of the carrier on the back side of the wafer and the flexibility of the carrier for materials with a long processing time, such as a wafer with high hardness (Degrees of parallelism) deteriorated, and sufficient processing accuracy could not be obtained.

  SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, an object of the present invention is to provide a single-sided wafer processing method capable of accurately processing one side of many wafers by a single process in a double-sided processing apparatus. To do.

In order to solve the above problems, the present invention provides a wafer carrier having a plurality of recesses on the upper and lower surfaces that are larger than the diameter of the wafer and shallower than the thickness of the wafer;
Adsorbing the wafer with liquid in the recess of the carrier;
And a lapping step of lapping the single side of the wafer by setting the carrier on which the wafer is adsorbed on a double-sided processing apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, the single-sided processing method of the wafer which can process accurately about the single side | surface of many wafers by one process in a double-sided processing apparatus can be provided.

Explanatory drawing of the carrier which concerns on 1st Embodiment Explanatory drawing of the process which prepares the carrier which concerns on 1st Embodiment. Top view when the carrier is set in the double-sided processing apparatus in the first embodiment Sectional drawing in the BB 'line in FIG.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.
[First Embodiment]
In this embodiment, a method for processing a single side of a wafer according to the present invention will be described.

The single-sided processing method of the wafer of this embodiment is as follows:
Preparing a wafer carrier having a plurality of recesses on the upper and lower surfaces that are larger than the diameter of the wafer and shallower than the thickness of the wafer;
Adsorbing the wafer with liquid in the recess of the carrier;
A lapping process for setting the carrier having adsorbed the wafer on a double-sided processing apparatus and lapping one side of the wafer.

  Each process will be described in turn.

  First, the outline of the carrier prepared in the step of preparing the carrier will be described with reference to FIG.

  Fig.1 (a) has shown the side view of a carrier, FIG.1 (b) has shown the figure seen from the upper surface side shown by the arrow A in Fig.1 (a).

  As shown in FIG. 1A, the carrier 10 has a plurality of recesses 11 for accommodating wafers on the upper and lower surfaces thereof.

  The size of the recess 11 is not particularly limited, but the diameter d of the recess is larger than the diameter of the wafer so that the wafer can be accommodated and so that the wafer is not damaged when the wafer is loaded and unloaded. It has become.

  At this time, the lower limit value of the diameter d of the concave portion only needs to be larger than the diameter of the wafer as described above. However, in consideration of operability when the wafer is mounted in the concave portion, it is 100.5% or more of the diameter of the wafer. It is preferable that it is 101% or more.

  The upper limit of the diameter d of the recess is not particularly limited, but if it is too large, the number of recesses that can be formed on the carrier is reduced, and the wafer may be easily detached from the recess during processing. For this reason, the diameter d of the recess is preferably 105% or less of the diameter of the wafer to be set, and more preferably 102% or less.

  The depth h of the recess is not particularly limited as long as it is shallower than the thickness of the wafer so that the polished portion of the wafer is exposed from the carrier surface, but it is set if the depth of the recess is too shallow. Therefore, the depth of the wafer is preferably 30% or more, more preferably 40% or more of the thickness of the wafer.

  The upper limit of the depth of the recess can be selected depending on the polishing amount and the like, and is not particularly limited as described above. For example, it is preferably 90% or less of the thickness of the wafer, more preferably 80% or less. preferable.

  There is no particular limitation on the arrangement of the concave portions as long as they are provided at least on the upper and lower surfaces of the carrier. For example, as shown in FIG. 1B, a plurality can be arranged along the circumference, or can be arranged randomly in the plane. Moreover, it can also be set as a different arrangement | positioning by the upper and lower surfaces. However, in order to polish the wafers arranged on the upper and lower surfaces more uniformly, it is preferable that the arrangement of the recesses is the same so that the resistance to the polishing pad is equal on the upper and lower surfaces.

  Moreover, although it is preferable that the recessed part formed in one carrier is uniform in size, the thing of a different size may be mixed.

  Specifically, for example, when polishing wafers of different sizes, a configuration in which recesses of different sizes are mixed can be used. However, in order to polish the wafer more uniformly, it is more preferable that the size of the recesses on at least the same surface (upper surface or lower surface) in the carrier is equal so that the resistance to the polishing pad becomes equal. It is more preferable that the size is uniform.

  Next, a method for manufacturing the carrier, that is, a configuration example of a process for preparing the carrier will be described.

  The step of preparing the carrier is not particularly limited as long as the carrier can be prepared (manufactured).

  The step of preparing the carrier includes, for example, a step of preparing a circular plate whose upper and lower surfaces are flat surfaces, and a concave portion that forms a concave portion that is larger than the wafer diameter and shallower than the wafer thickness on the upper and lower surfaces of the disk. And a process (method) having a forming process.

  More specifically, the above-described carrier is obtained by preparing a disk whose upper and lower surfaces are flat surfaces, and grinding and polishing (counterboring) the above-described concave portion at a desired position of the disk. be able to.

  At this time, the material of the disk used as the raw material is not particularly limited, and can be selected according to the material of the wafer used for polishing, the required durability, and the like.

  In particular, in order to impart sufficient durability, a material that can withstand friction with a wafer during polishing is preferable, and specifically, various metals and ceramics are preferable. In particular, in consideration of corrosion resistance to the polishing liquid, stainless steel or the like can be used as the metal, and alumina, zirconia, or the like can be used as the ceramic.

  As another method, the step of preparing the carrier includes a step of preparing a disk whose upper and lower surfaces are flat surfaces, and the upper and lower surfaces of the disk are larger than the diameter of the wafer and shallower than the thickness of the wafer. Bonding a template having a plurality of through-holes.

  This will be described with reference to FIG. In FIG. 2A, the upper diagram shows a top view of the template 20, and the lower diagram shows a cross-sectional view taken along the line AA ′ in the upper diagram. FIG. 2B is a cross-sectional view when the template 20 is bonded to the upper and lower surfaces of the disk 22.

  As shown in FIG. 2A, the template is provided with a plurality of through-holes 21 and the through-holes form a recess as will be described later. Therefore, the template has the same shape, size, and arrangement as described above. It can be.

  As shown in FIG. 2 (b), the template 20 is bonded to the upper and lower surfaces of the disc 22 to form the recess 11 by the through hole 21 provided in the template and the upper and lower surfaces of the disc 22. The wafer carrier described above can be formed.

  Here, the material of the template 20 is not particularly limited, but in consideration of workability and the like, various metals or resins are preferable. The size of the template 20 is not particularly limited, but the diameter is preferably the same as that of the disk 22 and can be smaller than the disk 22. Further, since the thickness corresponds to the depth of the recess 11, it is preferable to select the thickness of the template 20 so as to be a desired depth of the recess 11.

  Moreover, although it does not specifically limit about the disc 22, It is preferable that it consists of various metals, resin, or ceramics, for example.

  However, when processing is performed, a load may be applied to the disk that forms the bottom of the recess due to rotation of the wafer or the like. As a result, when the disk portion is worn or the like, the parallelism (support accuracy) of the wafer supported by the carrier decreases, and the processing accuracy may decrease. For this reason, in order to improve processing accuracy, it is preferable to use a material having high hardness so that the disc 22 supporting the wafer is not easily worn, and the disc 22 is more preferably made of metal or ceramics. In particular, considering the corrosion resistance and the like, it is possible to more preferably use stainless steel or the like as the metal and alumina or zirconia or the like as the ceramic.

  Moreover, the method of bonding the template 20 and the disk 22 is not particularly limited, and the template 20 and the disk 22 can be bonded with various adhesives or fixed to the disk with a fixing member.

  When a carrier is formed by sticking a template to a disk in this way, even if any member is damaged, it can be used simply by replacing the damaged member. It is preferable from the viewpoint of reduction.

  Here, two examples of the step of preparing the carrier have been described, but the present invention is not limited to these examples, and any method that can be processed into a similar shape may be used.

  However, in the double-side processing apparatus, when the wafer set in the concave portion of the carrier is lapped, the wafer may rotate in the concave portion while being pressed by the polishing pad. For this reason, the bottom portion of the recess (the portion 11A in FIG. 1A) is particularly likely to be loaded and easily worn. If the bottom of the recess is worn, the supporting wafer may be tilted in the recess or vibrated during processing, which may reduce the processing accuracy (parallelism). For this reason, it is preferable that at least the bottom portion of the recess is made of metal or ceramics so that the above-described wear does not occur. In particular, considering the corrosion resistance and the like, it is possible to more preferably use stainless steel or the like as the metal and alumina or zirconia or the like as the ceramic.

  Next, the process of adsorbing the wafer with the liquid in the concave portion of the carrier will be described.

  As described above, a plurality of recesses are formed on the upper and lower surfaces of the carrier. And it is necessary to fix a wafer in the said recessed part so that a wafer may not remove | desorb when setting to a double-sided processing apparatus. In particular, since the lower surface side of the carrier easily falls (detaches) due to its own weight, it is necessary to fix the wafer in the concave portion of the carrier.

  Therefore, in the wafer single-side processing method of this embodiment, a liquid is disposed at least between the wafer and the carrier (concave portion), and the wafer is fixed by adsorbing the wafer into the concave portion of the carrier.

  Specifically, the liquid can be disposed on the surface disposed in the recess of the carrier of the wafer and / or the recess of the carrier, and the wafer can be disposed and adsorbed in the recess of the carrier.

  Since the upper surface side of the carrier is supported by the carrier, the liquid may not be disposed, and the wafer may be directly disposed in the concave portion of the carrier.

  Since no wax or adhesive is used as a means for fixing the wafer as in the prior art, the wafer can be easily removed after the processing is completed, and the process of removing the wax and adhesive is not necessary. For this reason, contamination and breakage of the wafer are suppressed, and a cleaning process or the like is not required, so that productivity can be improved.

  The type of liquid used for adsorbing the wafer is not particularly limited as long as it can adsorb the wafer to the carrier, and is a liquid contained in a polishing liquid used in a lapping process described later. Is preferred. This makes it possible to prevent contamination of the polishing liquid even if the liquid used for wafer adsorption is mixed with the polishing liquid during processing if the liquid is contained in the polishing liquid. It is to become.

  Since the polishing liquid generally uses water or oil as a dispersion liquid for dispersing abrasive grains, water or oil can be used as a liquid when adsorbing the wafer to the carrier. More preferably, it is used.

  Next, a lapping process for setting the carrier that has adsorbed the wafer to a double-sided processing apparatus and lapping one side of the wafer will be described.

  The lapping process is performed by setting the carrier holding and holding the wafer in the double-sided processing apparatus as described above.

  Here, in FIG. 3, the top view at the time of setting the carrier 10 to a double-sided processing apparatus is shown. Further, FIG. 4 shows a cross-sectional view taken along line BB ′ at this time. FIG. 3 shows a state in which the upper surface plate and the polishing pad fixed to the upper surface plate are not set for easy understanding of the configuration.

  As shown in FIG. 3, after the gear member 31 is mounted around the carrier 10 so that the carrier 10 can rotate and revolve by being engaged with the sun gear 32 and the internal gear 33 of the double-sided processing device in the double-sided processing device, Set on the double-sided processing equipment. At this time, the carrier 10 and the gear member 31 are preferably fixed with an adhesive or the like so as not to be detached during processing.

  The material of the gear member 31 is not particularly limited, but preferably corresponds to the material of the sun gear or the internal gear, and is preferably made of metal, for example. The gear member 31 is preferably the same thickness as the carrier 10 or thinner than the carrier 10 so as not to contact the polishing pad during polishing.

  As shown in FIG. 4, the polishing pads 41 and 42 fixed to the upper surface plate and the lower surface plate are pressed against the carrier provided with the gear member set in the double-sided processing apparatus from the upper surface side and the lower surface side, respectively. In this state, a polishing liquid is supplied between the polishing pad and the wafer 43 from a supply port (not shown), and the sun gear 32 and the internal gear 33 are rotated at a desired speed, whereby the carrier is brought into the double-sided processing apparatus. One side of the wafer 43 can be lapped by revolving and rotating.

  The wafer single-side processing method according to the present embodiment has been described above, but the wafer single-side processing method according to the present embodiment can be suitably used particularly for processing difficult-to-polish wafers. Among them, it can be preferably used when the wafer has a Mohs hardness of 9 or more.

This is because it is often difficult to cut a hard-to-polish wafer from an ingot into a wafer shape with a high degree of parallelism. In the case of carrying out, the machining accuracy was low. On the other hand, according to the single-sided processing method of this embodiment, since it can grind | polish, supporting the one surface with a carrier, it becomes possible to grind | polish with high precision. As the wafer having the Mohs hardness, for example, the single-side processing method described in this embodiment for a sapphire or SiC wafer can be more preferably used.
[Second Embodiment]
In the present embodiment, a wafer manufacturing method using the wafer single-side processing method described in the first embodiment will be described.

The wafer can be manufactured, for example, by a manufacturing method having the following steps.
(A) A step of cutting the wafer from the ingot (b) A step of polishing both surfaces (upper and lower surfaces) of the wafer (c) A step of polishing the wafer end surface (d) A step of processing one side of the wafer (e) A wafer Step of washing The step is not limited to the above step, and various steps can be added as necessary. Further, the steps (b) to (d) are not limited to the above order, and can be performed in any order as necessary. The steps (b) to (d) relating to the polishing can be performed a plurality of times with different degrees of polishing, and also in this case, the polishing steps can be performed in an arbitrary order.

  The wafer single-side processing method described in the first embodiment can be applied in the step (d). Since the specific configuration and procedure of the single-sided processing method are as described in the first embodiment, they are omitted here.

  According to the wafer manufacturing method of the present embodiment, when processing one surface of a wafer, such as polishing, it is possible to accurately process one surface of many wafers by one processing in a double-side processing apparatus. For this reason, the productivity of the wafer manufacturing method can be improved and a wafer with higher processing accuracy can be manufactured.

10 Carrier 11 Recess 20 Template 21 Through-hole 43 Wafer

Claims (7)

Preparing a wafer carrier having a plurality of recesses on the upper and lower surfaces that are larger than the diameter of the wafer and shallower than the thickness of the wafer;
Adsorbing the wafer with liquid in the recess of the carrier;
A lapping process for setting the carrier having adsorbed the wafer on a double-sided processing apparatus and lapping the single side of the wafer. Preparing the carrier comprises the steps of:
Preparing a disk whose upper and lower surfaces are flat surfaces;
The method for forming a single-sided wafer according to claim 1, further comprising: forming a recess larger than the diameter of the wafer and shallower than the thickness of the wafer on the upper and lower surfaces of the disk. Preparing the carrier comprises the steps of:
Preparing a disk whose upper and lower surfaces are flat surfaces;
The wafer single-sided processing method according to claim 1, further comprising a step of bonding a template having a plurality of through-holes larger than the wafer diameter and shallower than the wafer thickness to the upper and lower surfaces of the disc.   The single-sided processing method for a wafer according to any one of claims 1 to 3, wherein the wafer is made of a material having a Mohs hardness of 9 or more.   5. The wafer single-side processing method according to claim 1, wherein the liquid is a liquid contained in a polishing liquid used in the lapping process. 6.   The single-sided wafer processing method according to any one of claims 1 to 5, wherein in the lapping step, the single-sided lapping of the wafer is performed by revolving and rotating the carrier in a double-sided processing apparatus. A wafer manufacturing method using the wafer single-side processing method according to claim 1.

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