JP2015226043A - Wafer ID reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer ID reader that is able to restrict a large size and a high price.SOLUTION: A wafer ID reader (1) that detects an ID mark (23) for identifying a wafer (21): comprises: a reading part (9) that detects an ID mark formed on a wafer; a first path (L1) composed of one or two or more mirrors (5) that guide first reflection light reflected from one face of the wafer; a second path (L2) composed of one or two or more mirrors (5b, 5c) that guides second reflection light reflected from the other face of the wafer; joining means (7) that joins the first and second paths; a third path (L3) that guides first reflection light and second reflection light to the reading part from the joining means; reflection-light selection means (11) that selectively guides the first reflection light or second reflection light to the reading part; and control means that controls the reflection-light selection means.

Description

  The present invention relates to a wafer ID reader for reading an ID mark for identifying a wafer.

  In the manufacturing process of a semiconductor device, various processings are performed on a wafer made of a semiconductor material such as silicon. For example, the processing history of the wafer is managed based on an identification ID mark formed on the front surface or the back surface (see, for example, Patent Document 1). The wafer ID mark can be read by an optical wafer ID reader.

  In recent years, a wafer ID reading apparatus including two sets of reading units respectively corresponding to the front side and the back side of a wafer has been proposed (see, for example, Patent Document 2). According to this wafer ID reading apparatus, the ID mark formed on the front surface or the back surface of the wafer can be appropriately read by each reading unit.

Japanese Patent Laid-Open No. 9-7777 JP-A-2005-45033

  However, if two sets of reading units are provided as described above, the wafer ID reading apparatus becomes large and expensive. The present invention has been made in view of such problems, and an object of the present invention is to provide a wafer ID reading apparatus capable of suppressing an increase in size and cost.

  According to the present invention, there is provided a wafer ID reading device for detecting an ID mark for identifying a wafer formed on one surface of a wafer or the other surface opposite to the one surface. A light source that illuminates the surface and the other surface, a holding table that has a smaller diameter than the wafer and that sucks and holds one or the other surface of the wafer, and a rotating means that rotates the holding table; A reader for detecting an ID mark formed on the wafer; a first path composed of one or more mirrors for guiding the first reflected light reflected by one surface of the wafer; and the other of the wafer A second path composed of one or more mirrors for guiding the second reflected light reflected by the surface, a merging means for merging the first path and the second path, and the merging means To the reading unit from the first A third path that guides the reflected light and the second reflected light; and a reflected light selection means that selectively guides either the first reflected light or the second reflected light to the reading unit; There is provided a wafer ID reader having control means for controlling the reflected light selection means.

  In the present invention, the merging means is preferably a beam splitter.

  In the present invention, the reflected light selecting means includes a mask member having an opening that allows light to pass through and a light shielding part that blocks light, and a mask member moving means that moves the mask member, and the control means includes: When the ID mark formed on one surface of the wafer is detected by moving the mask member by the mask member moving means, the opening is positioned on the first path and the light shielding portion is When the ID mark formed on the other surface of the wafer is positioned on the second path, the opening is positioned on the second path and the light-shielding part is positioned on the first path. Positioning is preferred.

  In the present invention, the light source includes a first light source that illuminates one surface of the wafer and a second light source that illuminates the other surface of the wafer, and the one surface and the other surface of the wafer. The control means turns on the first light source and turns off the second light source when detecting the ID mark formed on the one surface. Then, when the first reflected light reaches the reading unit via the first path and the third path and the ID mark formed on the other surface is detected, the first reflected light is detected. The second light source is turned on, the first light source is turned off, and the second reflected light reaches the reading unit via the second path and the third path, It is preferable that one light source and the second light source function as the reflected light selection unit.

  The wafer ID reading device according to the present invention has a first path for guiding the first reflected light reflected by one surface of the wafer and a second path for guiding the second reflected light reflected by the other surface of the wafer. , A merging means for merging the first path and the second path, a third path for guiding the first reflected light and the second reflected light from the merging means to the reading section, and a second path for the reading section. Reflection light selecting means for selectively guiding either one of the reflected light and the second reflected light, so that the first reflected light reflected on one surface of the wafer and the reflected light on the other surface are reflected. Both of the reflected second reflected lights can be read by a set of reading units.

  That is, in the present invention, unlike the conventional wafer ID reading apparatus, the ID marks formed on one surface and the other surface of the wafer are detected without using two sets of reading units, so that the size and cost are increased. It is possible to provide a wafer ID reading device capable of suppressing the formation of the wafer ID.

FIG. 1A is a partial cross-sectional side view schematically showing a configuration example of a wafer ID reading apparatus according to this embodiment, and FIG. 1B is a diagram of a reflected light selection unit provided in the wafer ID reading apparatus. It is sectional drawing which shows the example of a structure typically. It is a perspective view which shows the example of a wafer typically. FIG. 3A is a partial cross-sectional side view schematically showing how the upper surface ID mark is detected by the wafer ID reader, and FIG. 3B shows the lower surface ID mark by the wafer ID reader. It is a partial cross section side view which shows a mode that is detected. It is a perspective view showing typically an example of composition of a grinding device provided with a wafer ID reading mechanism including a wafer ID reading device concerning this embodiment. FIG. 5A is a partial cross-sectional side view schematically showing how the upper surface ID mark is detected by the wafer ID reader according to the modification, and FIG. 5B is a wafer according to the modification. It is a partial cross section side view which shows typically a mode that the ID mark of a lower surface is detected with an ID reader.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1A is a partial cross-sectional side view schematically showing a configuration example of a wafer ID reading apparatus according to the present embodiment. As shown in FIG. 1A, the wafer ID reading device 1 includes a disk-shaped holding table 3 having a diameter smaller than that of the wafer 21.

  The holding table 3 is connected to a rotating mechanism (rotating means) (not shown) such as a motor, and rotates around a rotating shaft extending in the vertical direction. The upper surface of the holding table 3 is a holding surface 3 a that sucks and holds the central portion of the wafer 21. The holding surface 3 a is connected to a suction source (not shown) through a flow path (not shown) formed inside the holding table 3.

  A light source (not shown) that illuminates the upper surface (one surface) and the lower surface (the other surface) of the wafer 21 is installed at a position close to the holding table 3. At a position higher than the holding surface 3a of the holding table 3, a first mirror 5a and a beam splitter (merging means) 7 are arranged in order from the holding table 3 side.

  The first mirror 5a reflects light from the light source (first reflected light) reflected by the upper surface of the wafer 21 in a substantially horizontal direction. The beam splitter 7 transmits the first reflected light reflected by the first mirror 5 a and guides it to a reading unit (reading unit) 9 installed at substantially the same height as the beam splitter 7.

  On the other hand, at a position lower than the holding surface 3a of the holding table 3, a second mirror 5b and a third mirror 5c are arranged in order from the holding table 3 side. The second mirror 5b is positioned below the first mirror 5a, and the third mirror 5c is positioned below the beam splitter 7.

  The second mirror 5 b reflects light from the light source (second reflected light) reflected by the lower surface of the wafer 21 in a substantially horizontal direction. The third mirror 5c reflects the second reflected light reflected by the second mirror 5b upward. The second reflected light reflected by the third mirror 5 c is reflected by the beam splitter 7 in the horizontal direction and guided to the reading unit (reading unit) 9.

  That is, a first path (first optical path) L1 (see FIG. 3A) for guiding the first reflected light to the beam splitter 7 is formed by the first mirror 5a. The second mirror 5b and the third mirror 5c form a second path (second optical path) L2 (see FIG. 3B) that guides the second reflected light to the beam splitter 7. Yes.

  The first path L1 and the second path L2 described above merge at the beam splitter 7. Between the beam splitter 7 and the reading unit 9, a third path (third optical path) L3 for guiding the first reflected light or the second reflected light to the reading unit 9 (see FIG. 3A, etc.) ) Is formed. The reading unit 9 can detect the ID mark 23 of the wafer 21 based on the first reflected light or the second reflected light guided by the third path L3.

  The first reflected light and the second reflected light are selectively read at positions between the first mirror 5a and the beam splitter 7 and between the second mirror 5b and the third mirror 5c. A reflected light selection unit (reflected light selection means) 11 that leads to the unit 9 is arranged. FIG. 1B is a perspective view schematically showing a configuration example of the reflected light selection unit 11 provided in the wafer ID reading device 1.

  As shown in FIGS. 1A and 1B, the reflected light selection unit 11 includes a plate-like mask member 13. The mask member 13 includes a light blocking portion 13a that blocks light and an opening portion 13b that allows light to pass through. For example, the opening 13b is formed in a rectangular shape at the center of the light shielding portion 13a. However, the shape of the light shielding part 13a and the opening part 13b is not particularly limited.

  Below the mask member 13, a moving mechanism (mask member moving means) 15 for moving the mask member 13 is provided. The moving mechanism 15 includes an air cylinder 15a connected to an air supply source (not shown), and a piston rod 15b inserted through the air cylinder 15a at the lower end side.

  The upper end portion of the piston rod 15 b is fixed to the lower end portion of the mask member 13. The mask member 13 moves up and down together with the piston rod 15b by the pressure of air supplied from an air supply source (not shown), and is positioned at the upper first position or the lower second position. The elevation of the mask member 13 is controlled by a control device (control means) (not shown).

  When the mask member 13 is positioned at the first position, the opening 13b is positioned on the first path L1 (see FIG. 3A) that guides the first reflected light to the beam splitter 7. The light shielding portion 13a is positioned on the second path L2 (see FIG. 3A) that guides the second reflected light to the beam splitter 7.

  On the other hand, when the mask member 13 is positioned at the second position, the opening 13b is positioned on the second path L2 (see FIG. 3B) that guides the second reflected light to the beam splitter 7. In addition, the light shielding portion 13a is positioned on the first path L1 (see FIG. 3B) that guides the first reflected light to the beam splitter 7. The mask member 13 is formed in a mode suitable for this operation.

  FIG. 2 is a perspective view schematically showing an example of the wafer 21. As shown in FIG. 2, the wafer 21 is a circular plate-shaped object formed of a semiconductor material such as silicon. The wafer 21 has a substantially flat front surface 21a and back surface 21b, and a notch 21c indicating a crystal orientation is formed on the outer peripheral edge.

  On the surface 21 a side of the wafer 21, an ID mark 23 for identifying the wafer 21 is formed at a position close to the notch 21 c. However, the ID mark 23 may be formed on the back surface 21 b side of the wafer 21. The ID mark 23 can be formed by a method such as laser engraving.

  In FIG. 1A, the back surface 21b side of the wafer 21 is sucked and held by the holding table 3, and the front surface 21a side is positioned upward. That is, in FIG. 1A, the front surface 21a of the wafer 21 is the upper surface (one surface), and the back surface 21b of the wafer 21 is the lower surface (the other surface).

  Next, the operation of the wafer ID reading apparatus 1 according to this embodiment will be described. FIG. 3A is a partial cross-sectional side view schematically showing how the ID mark 23 on the upper surface is detected by the wafer ID reader 1, and FIG. 3B shows the lower surface of the wafer ID reader 1. It is a partial cross section side view showing typically signs that ID mark 23 of is detected.

  In FIG. 3A, the back surface 21b side of the wafer 21 is sucked and held by the holding table 3, and the front surface 21a side with the ID mark 23 is positioned upward. On the other hand, in FIG. 3B, the surface 21a side of the wafer 21 is sucked and held by the holding table 3, and the surface 21a side with the ID mark 23 is positioned downward.

  As shown in FIG. 3A, when detecting the ID mark 23 on the upper surface, first, the mask member 13 is moved to the first position by the control device, and the light source reflected by the ID mark 23 on the upper surface. The light (first reflected light) can be guided to the beam splitter 7.

  As described above, when the mask member 13 is positioned at the first position, the opening 13b is positioned on the first path L1 that guides the first reflected light to the beam splitter 7, and the light shielding unit 13a is It is positioned on the second path L2 that guides the second reflected light to the beam splitter 7.

  As a result, only the first reflected light is guided to the third path L3 from the beam splitter 7 to the reading unit 9. That is, since the second reflected light is blocked by the mask member 13 and does not reach the reading unit 9, only the first reflected light is detected by the reading unit 9, and the ID mark 23 on the upper surface of the wafer 21 is appropriately detected. It can be detected.

  On the other hand, as shown in FIG. 3B, when detecting the ID mark 23 on the lower surface, first, the mask member 13 is moved to the second position by the control device and reflected by the ID mark 23 on the lower surface. The light from the light source (second reflected light) can be guided to the beam splitter 7.

  As described above, when the mask member 13 is positioned at the second position, the opening 13b is positioned on the second path L2 that guides the second reflected light to the beam splitter 7, and the light shielding unit 13a is It is positioned on the first path L1 that guides the first reflected light to the beam splitter 7.

  Thus, only the second reflected light is guided to the third path L3 from the beam splitter 7 to the reading unit 9. That is, since the first reflected light is blocked by the mask member 13 and does not reach the reading unit 9, only the second reflected light is detected by the reading unit 9, and the ID mark 23 on the lower surface of the wafer 21 is appropriately set. It can be detected.

  As described above, the wafer ID reader 1 according to this embodiment includes the first path L1 that guides the first reflected light reflected by the upper surface (one surface) of the wafer 21 and the lower surface (the other surface) of the wafer 21. A second path L2 for guiding the second reflected light reflected by the surface), a beam splitter (merging means) 7 for merging the first path L1 and the second path L2, and a reading unit from the beam splitter 7. (Reading unit) The third path L3 that guides the first reflected light and the second reflected light to the reading unit 9, and selectively either one of the first reflected light or the second reflected light to the reading unit 9. And a reflected light selection unit (reflected light selection means) 11 for guiding the first reflected light reflected on the upper surface of the wafer 21 and a second reflected light reflected on the lower surface. 9 can read

  That is, in this embodiment, since the ID mark 23 formed on the upper surface and the lower surface of the wafer 21 is detected without using two sets of reading units as in the conventional wafer ID reading device, the size and the price are increased. Can be provided.

  Next, a configuration example of a processing apparatus including a wafer ID reading mechanism including the wafer ID reading apparatus 1 according to the present embodiment will be described. FIG. 4 is a perspective view schematically illustrating a configuration example of a grinding apparatus including a wafer ID reading mechanism including the wafer ID reading apparatus 1 according to the present embodiment. Note that the wafer ID reading mechanism including the wafer ID reading device 1 according to the present embodiment may be incorporated in another processing device such as a cutting device.

  As shown in FIG. 4, the grinding device (processing device) 2 includes a base 4 that supports each component. An opening 4 a is formed on the front end side of the upper surface of the base 4, and a transfer mechanism 6 for transferring the wafer 21 to be processed is provided in the opening 4 a. Further, cassettes 8a and 8b capable of accommodating the wafer 21 are placed in a region further forward of the opening 4a.

  An alignment mechanism 10 is provided behind the placement area on which the cassette 8a is placed and the opening 4a, for example, to align the temporarily placed wafer 21 so that the back surface 21b side is exposed upward. For example, the alignment mechanism 10 aligns the center of the wafer 21 that is transported from the cassette 8a by the transport mechanism 6 and temporarily placed on the holding table.

  A wafer ID reading mechanism 12 including the wafer ID reading device 1 according to the present embodiment is provided at a position close to the alignment mechanism 10. By reading the ID mark of the wafer 21 with the wafer ID reading mechanism 12, for example, it is possible to optimize the grinding conditions according to the processing history.

  In the present embodiment, for example, the ID mark 23 of the wafer 21 that has been aligned is detected. In the grinding apparatus 2, a holding table for holding the wafer 21 is shared between the alignment mechanism 10 and the wafer ID reading mechanism 12. For example, the wafer ID reading mechanism 12 has an ID mark on the surface 21 a positioned below. 23 is detected.

  At a position adjacent to the alignment mechanism 10 and the wafer ID reading mechanism 12, a carry-in mechanism 14 that sucks and holds the wafer 21 and rotates is disposed. For example, the carry-in mechanism 14 sucks the back surface 21b side so that the front surface 21a side of the wafer 21 is exposed downward, and transports the wafer 21 aligned by the alignment mechanism 10 backward.

  A rotatable turntable 16 is disposed behind the carry-in mechanism 14. Three chuck tables 18 for sucking and holding the wafer 21 are provided on the upper surface of the turntable 16. Note that the number of chuck tables 18 arranged on the turntable 16 is not necessarily limited to three.

  The wafer 21 sucked and held by the carry-in mechanism 14 is carried into each chuck table 18 with the surface 21a side positioned downward. Each chuck table 18 is connected to a rotation mechanism (not shown) such as a motor, and rotates around a rotation axis extending in the vertical direction.

  The upper surface of each chuck table 18 is a holding surface 18 a that holds the wafer 21 by suction. The holding surface 18 a is connected to a suction source (not shown) through a flow path (not shown) formed inside the chuck table 18. The wafer 21 carried into each chuck table 18 is sucked on the surface 21a side by the negative pressure of the suction source acting on the holding surface 18a.

  Two support structures 20 extending upward are provided behind the turntable 16. A Z-axis movement table 24 is provided on the front surface of each support structure 20 via a Z-axis movement mechanism 22. Each Z-axis moving mechanism 22 includes a pair of Z-axis guide rails 26 parallel to the Z-axis direction, and a Z-axis moving table 24 is slidably installed on the Z-axis guide rails 26.

  A nut portion (not shown) is fixed to the rear surface side (back surface side) of each Z-axis moving table 24, and a Z-axis ball screw 28 parallel to the Z-axis guide rail 26 is screwed to the nut portion. ing. A Z-axis pulse motor 30 is connected to one end of each Z-axis ball screw 28. When the Z-axis ball screw 28 is rotated by the Z-axis pulse motor 30, the Z-axis moving table 24 moves in the Z-axis direction along the Z-axis guide rail 26.

  A grinding mechanism 32 is provided on the front surface (surface) of each Z-axis moving table 24. Each grinding mechanism 32 includes a spindle housing 34 fixed to the Z-axis moving table 24. A spindle (not shown) is rotatably supported on each spindle housing 34.

  A grinding wheel 36 is attached to the lower end side of each spindle. Each grinding wheel 36 includes a cylindrical wheel base formed of a metal material such as aluminum or stainless steel, and a plurality of grindstones arranged in an annular shape on the lower surface of the wheel base.

  When the loaded wafer 21 is sucked and held by the chuck table 18, the turntable 16 rotates to position the wafer 21 below the grinding mechanism 32. The wafer 21 is ground by rotating the chuck table 18 and the grinding wheel 36, lowering the grinding mechanism 32 by the Z-axis moving mechanism 22, and bringing the grinding wheel 36 into contact with the back surface 21 b of the wafer 21.

  At a position adjacent to the carry-in mechanism 14, a carry-out mechanism 38 that rotates by sucking and holding the ground wafer 21 is provided. A cleaning mechanism 40 that cleans the ground wafer 21 that has been unloaded by the unloading mechanism 38 is disposed in front of the unloading mechanism 38 and behind the opening 4a. The wafer 21 cleaned by the cleaning mechanism 40 is transferred by the transfer mechanism 6 and stored in the cassette 8b.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. FIG. 5A is a partial cross-sectional side view schematically showing how the upper surface ID mark is detected by the wafer ID reader according to the modification, and FIG. 5B is a wafer according to the modification. It is a partial cross section side view which shows typically a mode that the ID mark of a lower surface is detected with an ID reader.

  As shown in FIGS. 5A and 5B, the wafer ID reading device 31 according to the modification includes a first light source 17 a that illuminates the upper surface (one surface) of the wafer 21, and the lower surface of the wafer 21. And a second light source 17b that illuminates (the other surface).

  The first light source 17a and the second light source 17b correspond to the light sources of the wafer ID reading device 1 according to the above embodiment. Further, the first light source 17a and the second light source 17b are configured to selectively illuminate the upper surface and the lower surface of the wafer 21 based on an instruction from the control device (control means), and the first reflection is performed. A function of a reflected light selection unit (reflected light selection means) 11 for selecting light and second reflected light is also provided. Other configurations may be the same as those of the wafer ID reader 1.

  As shown in FIG. 5A, when detecting the ID mark 23 on the upper surface, the control device turns on the first light source 17a and turns off the second light source 17b. As a result, only the light (first reflected light) of the first light source 17 a reflected by the ID mark 23 on the upper surface is guided to the beam splitter 7.

  As described above, since the light from the second light source 17b is not reflected by the lower surface of the wafer 21 by turning off the second light source 17b, only the first reflected light is detected by the reading unit 9. The ID mark 23 on the upper surface of the wafer 21 can be detected appropriately.

  On the other hand, as shown in FIG. 5B, when the ID mark 23 on the lower surface is detected, the control device turns on the second light source 17b and turns off the first light source 17a. Thereby, only the light (second reflected light) of the second light source 17 b reflected by the ID mark 23 on the lower surface is guided to the beam splitter 7.

  Thus, since the light from the first light source 17a is not reflected on the upper surface of the wafer 21 by turning off the first light source 17a, only the second reflected light is detected by the reading unit 9. The ID mark 23 on the lower surface of the wafer 21 can be detected appropriately.

  In addition, the configurations, methods, and the like according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 1 Wafer ID reader 3 Holding table 3a Holding surface 5a 1st mirror 5b 2nd mirror 5c 3rd mirror 7 Beam splitter (merging means)
9 Reading unit (reading unit)
11 Reflected light selection unit (reflected light selection means)
13 mask member 13a light shielding part 13b opening 15 moving mechanism (mask member moving means)
15a air cylinder 15b piston rod 17a first light source 17b second light source 21 wafer 21a front surface 21b back surface 21c notch 23 ID mark 31 wafer ID reader L1 first path (first optical path)
L2 Second path (second optical path)
L3 Third path (third optical path)
2 Grinding equipment (processing equipment)
4 Base 4a Opening 6 Transport mechanism 8a, 8b Cassette 10 Alignment mechanism 12 Wafer ID reading mechanism 14 Loading mechanism 16 Turntable 18 Chuck table 18a Holding surface 20 Support structure 22 Z-axis moving mechanism 24 Z-axis moving table 26 Z-axis guide rail 28 Z-axis ball screw 30 Z-axis pulse motor 32 Grinding mechanism 34 Spindle housing 36 Grinding wheel 38 Unloading mechanism 40 Cleaning mechanism

Claims (4)

A wafer ID reading device for detecting an ID mark for identifying a wafer formed on one surface of a wafer or the other surface opposite to one surface,
A light source that illuminates one side and the other side of the wafer;
A holding table having a smaller diameter than the wafer and sucking and holding one side or the other side of the wafer;
Rotating means for rotating the holding table;
A reading unit for detecting an ID mark formed on the wafer;
A first path composed of one or more mirrors for guiding the first reflected light reflected by one surface of the wafer;
A second path composed of one or more mirrors for guiding second reflected light reflected by the other surface of the wafer;
Merging means for merging the first path and the second path;
A third path for guiding the first reflected light and the second reflected light from the merging means to the reading unit;
Reflected light selection means for selectively guiding one of the first reflected light and the second reflected light to the reading unit;
And a control means for controlling the reflected light selection means.   2. The wafer ID reading apparatus according to claim 1, wherein the merging means is a beam splitter. The reflected light selecting means includes
A mask member having an opening that allows light to pass through and a light blocking part that blocks light; and
A mask member moving means for moving the mask member,
The control means includes
By moving the mask member by the mask member moving means,
When detecting the ID mark formed on one surface of the wafer, the opening is positioned on the first path and the light-shielding part is positioned on the second path,
2. When detecting an ID mark formed on the other surface of the wafer, the opening is positioned on the second path and the light-shielding part is positioned on the first path. Or the wafer ID reading apparatus of Claim 2. The light source includes a first light source that illuminates one surface of the wafer and a second light source that illuminates the other surface of the wafer, and can selectively illuminate one surface and the other surface of the wafer. Is configured as
When detecting the ID mark formed on the one surface, the control means turns on the first light source and turns off the second light source so that the first path and the third light source are turned off. When the first reflected light reaches the reading unit via the path and the ID mark formed on the other surface is detected, the second light source is turned on and the first light source is turned on. The light is turned off and the second reflected light reaches the reading unit via the second path and the third path, so that the first light source and the second light source are reflected by the reflected light. 3. The wafer ID reading device according to claim 1, wherein the wafer ID reading device is made to function as a selection unit.