JP2010207935A - Wafer machining method and numerical control blasting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer machining method by which a wafer having a suppressed variation in warpage and thickness can be obtained. <P>SOLUTION: The wafer machining method includes a step of providing a wafer 10a having an in-plane thickness distribution, a measuring step of measuring each of the coordinates of a plurality of in-plane positions of the wafer 10a and the thickness of the wafer 10a at each of the positions and acquiring information on the thickness distribution of the wafer 10a, and a thickness uniformizing step of machining the wafer 10a at least in a position, where the thickness is large, by a numerical control machining method based on the information on the thickness distribution to reduce the thickness of the position. The machining means used in the numerical control machining method is blasting. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wafer processing method and a numerically controlled blast processing apparatus.

  A semiconductor or piezoelectric wafer used as a raw material for various electronic devices is required to have at least no warping in the outer shape and a uniform thickness. Further, in the case where the wafer is composed of a single crystal, it is required that a specific crystal axis exactly matches the entire surface of the wafer with respect to the normal direction of the wafer. If the wafer is warped or uneven in thickness, the direction of the crystal axis will also vary within the wafer surface.

  For example, JP 2006-123020 A discloses a method for polishing a workpiece (piezoelectric wafer) using a planetary gear type polishing apparatus. The publication discloses that the thickness variation is suppressed by polishing both surfaces of the workpiece.

JP 2006-123020 A

  However, once warping or thickness variation occurs in the wafer, it is very difficult to correct it by polishing or the like. According to the inventor's study, it has been found that the warpage and thickness variation existing in the wafer before polishing cannot be eliminated by the conventional method of polishing the entire wafer surface, but also deteriorated. For example, when the wafer before polishing is cut out from an ingot or raw stone, the wafer may have a thickness variation. In such a wafer, the thickness variation and warpage may further increase during polishing.

  An object of some embodiments of the present invention is to provide a wafer processing method capable of obtaining a wafer in which variations in warpage and thickness are suppressed.

  One of the objects according to some embodiments of the present invention is to provide a numerically controlled blasting apparatus suitable for processing a wafer in order to obtain a wafer in which variations in warpage and thickness are suppressed.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
The wafer processing method according to the present invention includes:
Preparing a wafer having a thickness distribution in-plane;
A measurement step of measuring the coordinates of a plurality of positions in the surface of the wafer and the thickness of the wafer at each of the positions, and obtaining thickness distribution information of the wafer;
Based on the thickness distribution information, at least a position having a large thickness of the wafer is processed by a numerical control processing method, and a thickness uniformizing step for reducing the thickness at the position;
Including
The wafer processing method, wherein the processing means of the numerical control processing method is blast processing.

  In this way, the thickness variation in the wafer surface of the wafer before polishing can be reduced, and a wafer with reduced warpage and thickness variation can be obtained. In addition, since the processing speed can be made relatively high in this way, the time required for the thickness uniformizing process can be shortened.

[Application Example 2]
In application example 1,
The processing area of the processing means is an area having an area of 1/10000 to 1/4 of the processing surface of the wafer, and is scanned on the processing surface of the wafer.

  By doing so, it is possible to perform numerical control processing that is more faithful to the thickness distribution information obtained in the measurement step in the thickness equalization step.

[Application Example 3]
In application example 1 or application example 2,
The wafer processing method, wherein the wafer is a quartz substrate.

  In this way, it is possible to obtain a quartz wafer in which a specific crystal axis of quartz is aligned with respect to the normal direction of the wafer in a wide area of the wafer.

[Application Example 4]
In any one of the application examples 1 to 3,
A wafer processing method including a processing step of removing a work-affected layer formed on a processing surface of the wafer after the thickness uniformizing step.

  In this way, since the work-affected layer is removed, a wafer having more stable characteristics can be provided.

[Application Example 5]
In any one of the application examples 1 to 4,
A wafer processing method including a polishing step after the thickness uniforming step.

  In this way, the variation in thickness is reduced before the polishing step, and the polishing step is performed in a state without the variation, so that a wafer with reduced warpage and thickness variation can be obtained.

[Application Example 6]
A numerically controlled blasting apparatus according to the present invention is:
A mounting table for mounting a wafer having a thickness distribution;
A nozzle for discharging abrasive grains to the processing surface of the wafer;
A moving mechanism that scans at least one of the mounting table and the nozzle to change the position of the nozzle with respect to the processing surface;
A control unit that controls at least one of the moving mechanism and the discharge amount of the abrasive grains based on the thickness distribution information of the wafer and the processing speed information of the wafer by the abrasive particles discharged from the nozzle;
Is provided.

  Since such a numerically controlled blast processing apparatus operates based on wafer thickness distribution information and wafer processing speed information by abrasive grains discharged from nozzles, in order to obtain a wafer with reduced warpage and thickness variation. Is preferred.

[Application Example 7]
In Application Example 6,
The numerical control blasting apparatus, wherein the control mechanism controls at least a scanning speed of the moving mechanism.

  Since such a numerically controlled blast processing apparatus adjusts the processing amount according to the relative moving speed of the nozzle with respect to the processing surface, it is possible to form a wafer having a highly uniform thickness extremely easily.

A perspective view showing typically an example of wafer 10a concerning an embodiment. The perspective view which shows an example of the method of producing the wafer 10a of embodiment. The schematic diagram which shows a mode that the thickness of the wafer 10a of embodiment is measured. The schematic diagram which shows a mode that the thickness of the wafer 10a of embodiment is measured. A top view showing typically wafer 10a of an embodiment. The perspective view which shows typically the numerical control processing apparatus 100 of embodiment. A top view showing typically wafer 10a of an embodiment. Sectional drawing which shows typically the one aspect | mode of the homogenization process of the wafer 10a of embodiment. Sectional drawing which shows typically the one aspect | mode of the homogenization process of the wafer 10a of embodiment. A sectional view showing typically wafer 10a of an embodiment. A sectional view showing wafer 10 of an embodiment typically.

  Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, the following embodiment demonstrates an example of this invention.

  The wafer processing method according to this embodiment includes a wafer preparation step, a measurement step, and a thickness equalization step.

1. Process for Preparing Wafer FIG. 1 is a perspective view schematically showing a wafer 10a processed in this embodiment. FIG. 2 is a perspective view showing an example of a method for producing the wafer 10a processed in the present embodiment. In the following description, the subscript “a” of the wafer 10a and the like is added to indicate that the wafer 10a is in a state before undergoing the thickness equalization process of the present embodiment.

  As shown in FIG. 1, the wafer 10a has a flat plate shape. The wafer 10a has two main surfaces 12a and 14a. In FIG. 1, for convenience of explanation, the thickness direction (normal direction) of the wafer 10a is defined as the Z direction, and arrows indicating the X direction orthogonal to the Z direction and the Y direction orthogonal to the Z direction and the X direction are drawn. It is. In FIG. 1, a flat wafer 10a is drawn in parallel with the XY plane developed in the X direction and the Y direction. In FIG. 1, the thickness of the wafer 10a is exaggerated.

  The planar shape (the shape viewed from the Z direction) of the wafer 10a is a rectangle in the illustrated example, but is not limited thereto, and may be a circle or the like. Moreover, the average value of the thickness (width in the Z direction) of the wafer 10a can be set to 10 μm to 20 mm, for example. Examples of the material of the wafer 10a include piezoelectric materials such as quartz, lithium tantalate, and lithium niobate, semiconductor materials such as silicon and compound semiconductors, and oxide materials such as glass and sapphire. The material of the wafer 10a may be crystalline or amorphous.

  The wafer 10a prepared in this step has a thickness distribution in the plane. The state having an in-plane thickness distribution means a state in which the width (thickness) in the Z direction varies depending on the position in the XY plane, as shown in FIG. In the example of FIG. 1, both the upper surface 12a and the lower surface 14a are convex, and the thickness of the wafer 10a increases in the X direction. The thickness distribution of the wafer 10a is not limited to that illustrated, and the upper surface 12a or the lower surface 14a may have a wavefront with a period smaller than the width of the wafer 10a in the XY plane direction, You may have a convex part.

  The wafer 10a may be prepared in any way. For example, as the wafer 10a, various commercially available substrates may be prepared, or a wafer cut from a raw stone (such as quartz) or an ingot (such as silicon) may be prepared. Further, the wafer 10a may be a wafer having a thickness distribution in a polished state.

  FIG. 2 shows an example of a process for cutting out and preparing the wafer 10a from the raw stone. FIG. 2 shows how the wafer 10 a is cut out from the raw stone 1 by the wire saw 3. The rough 1 is fixed on the base 2. The wire saw 3 can penetrate the raw stone 1 at a predetermined angle and cut the raw stone 1. For example, a plurality of wafers 10a can be obtained as illustrated. The illustrated example shows a case where the wire 4 of the wire saw 3 is reciprocated in the extending direction with an abrasive, polishing slurry, or the like. In such a case, at the time of cutting the raw stone 1, the wire 4 is thinned, or the abrasive and the polishing slurry are concentrated on the end region of the raw stone 1. Therefore, in such a case, a wafer 10a having a thickness distribution as shown in FIG. 1 may be obtained.

2. Measurement Step FIGS. 3 and 4 are schematic views showing how the thickness of the wafer 10a is measured. FIG. 5 is a plan view of the wafer 10a.

  The measurement step is a step of acquiring thickness distribution information of the wafer 10a by measuring the coordinates of a plurality of positions in the plane of the wafer 10a and the thickness of the wafer 10a at each position.

  The thickness of the wafer 10a can be measured by an arbitrary method. For example, the thickness can be measured by a micrometer 5 as shown in FIG. Although not shown, the thickness of the wafer 10a can be measured by an optical method. When the wafer 10a is formed of a material capable of thickness-shear vibration such as an AT-cut crystal, the thickness can be measured more precisely. In this case, for example, as shown in FIG. 4, a voltage signal is applied in the thickness direction of the wafer 10a by a pair of probes 6 to measure the frequency of thickness shear vibration, and the thickness of the portion to which the voltage signal is applied is further increased. It can be measured accurately. In FIG. 4, the state of thickness shear vibration is indicated by a broken line. When the wafer 10a is an AT-cut quartz substrate, a relationship of f (MHz) = 1670 / t (μm) is established between the frequency f of thickness shear vibration and the thickness t.

  FIG. 5 shows an example of the arrangement of the thickness measurement points 7 on the wafer 10a. In the example of FIG. 5, orthogonal coordinates are taken on the XY plane of the wafer 10a. Accordingly, each measurement point 7 has an X coordinate and a Y coordinate, and the position of the thickness measurement point 7 on the wafer 10a can be specified by these. The method of taking coordinates on the XY plane of the wafer 10a is arbitrary, and may not be an orthogonal coordinate system. The number of measurement points 7 is arbitrary as long as it is plural. In the illustrated example, the number of measurement points 7 is 45 points. If the number of measurement points 7 is smaller than 4, information on the thickness distribution of the wafer 10a may be insufficient. If the number of measurement points 7 is too large, it may take a long time to measure the thickness of each point. Therefore, the number of measurement points 7 is preferably about 10,000 or less. Furthermore, although the measurement points 7 are arranged at equal intervals (in a grid pattern) in the illustrated example, the measurement points 7 are not limited to this, and may be densely provided at specific positions, for example.

  The thickness distribution information of the wafer 10a can be acquired by measuring the thickness of each measurement point 7 by the thickness measurement method described above. As the thickness distribution information of the wafer 10a, for example, the position coordinates (X coordinate and Y coordinate in the example of FIG. 5) and the thickness at one measurement point 7 are set, and the set is a set of the number of measurement points 7. Can be mentioned. Such thickness distribution information includes at least information regarding the thickness distribution in the Z direction in the XY plane of the wafer 10a.

3. Thickness equalization process In this process, based on the thickness distribution information of the wafer 10a acquired in “1.2. This is a process for reducing.

  This step is performed by a numerical control processing method. The numerically controlled machining method refers to a machining method in which a machining position and a machining amount are controlled based on thickness distribution information. The position where the thickness of the wafer 10a to be processed is large can be grasped from the thickness distribution information acquired in advance. In this step, the thickness of the position where the thickness of the wafer 10a is small may be reduced. Such a numerically controlled machining method can be performed by a numerically controlled machining apparatus as described below.

3.1. Numerical Control Processing Device FIG. 6 is a perspective view schematically showing a numerical control processing device 100 which is an example of a numerical control processing device. In the figure, for convenience of explanation, arrows indicating the Z direction which is the thickness direction (normal direction) of the wafer 10a, the X direction orthogonal to the Z direction, and the Y direction orthogonal to the Z direction and the X direction are drawn. It is.

  The numerically controlled processing apparatus 100 includes at least a mounting table 20, a processing tool 30, a moving mechanism 40, and a control unit 50.

  The mounting table 20 can mount the wafer 10a on the upper surface. The mounting table 20 may be provided with a suction mechanism for fixing the wafer 10a as necessary. The wafer 10 a is mounted on the mounting table 20 so that the processing surface (the upper surface 12 a in the illustrated example) faces upward, and the processing surface faces the processing tool 30. Therefore, in the illustrated example, the upper surface 12a of the wafer 10a is the processing surface. The mounting table 20 may be fixed, but may be configured to be movable in the XY plane by a moving mechanism 40 (for example, an XY stage 42) as illustrated in the figure.

  The processing tool 30 is a processing means for processing the wafer 10a, and is provided so as to face the processing surface of the wafer 10a. In the illustrated example, the processing tool 30 is drawn in a shape with a sharpened tip, but is not limited to such a shape. The processing tool 30 can process a part of the processing surface of the wafer 10a. The processing tool 30 has a function of removing a substance on the processing surface side of the wafer 10a, and can reduce the thickness of the wafer 10a at the facing portion. Examples of the processing tool 30 include a mode in which abrasive grains are ejected and collided with the wafer 10a for blasting. Since the blast processing has a high processing speed, the time required for the thickness equalization process can be shortened as compared with the plasma processing and the etching processing.

  FIG. 7 is a plan view schematically showing the wafer 10 a, and schematically shows an example of the processing region 31 of the processing tool 30 and scanning of the processing tool 30. The processing region 31 can be a region having an area of 1/10000 to 1/4 of the processing surface of the wafer 10a. That is, the size of the processing region 31 can be selected in accordance with the thickness distribution information of the given wafer 10a. If the processing region 31 is smaller than a region having an area of 1/10000 of the processing surface of the wafer 10a, the time required for processing may be long. If the processing region 31 is larger than a region having an area of ¼ of the processing surface of the wafer 10a, the thickness may be insufficiently uniform when the wafer 10a has fine irregularities. For example, when the density distribution information of the given wafer 10a is high in the surface to be processed (the number of measurement points 7 is large), the processing region 31 can be made smaller to increase the accuracy of uniform thickness. . Although depending on the content of the thickness distribution information of the wafer 10a and the scanning method of the processing tool 30, the time required for the thickness uniformizing process can be shortened by increasing the processing region 31. Since the area of the processing region 31 can be selected as appropriate, numerical control processing suitable for the information amount of the thickness distribution information obtained in the measurement step can be performed in the thickness uniformization step. Further, as shown in FIG. 7, the shape of the processing region 31 on the processing surface of the wafer 10a can be circular, elliptical, or the like, and is not particularly limited. Further, as shown in FIG. 7, the processing tool 30 may be scanned so that the processing regions 31 overlap.

  The moving mechanism 40 is arbitrary as long as the relative positions of the processing tool 30 and the mounting table 20 (wafer 10a) can be changed at least in the XY directions. According to the moving mechanism 40, the processing tool 30 can be scanned in the XY plane. The moving mechanism 40 can be driven by a stepping motor or the like in accordance with an external signal. For example, the configuration of the moving mechanism 40 can be at least one of an XY stage 42 that can move the mounting table 20 in the XY direction and a scanning mechanism 44 that can move the processing tool 30 in the XY direction. The scanning mechanism 44 illustrated in FIG. 6 can change the position of the scanning unit 46 in the XY directions. Thereby, the processing tool 30 connected to the scanning unit 46 can be scanned with respect to the processing surface of the wafer 10a.

  The control unit 50 controls at least the moving mechanism 40 based on the thickness distribution information of the wafer 10 a and the processing speed information of the wafer 10 a by the processing tool 30. As the processing speed information of the wafer 10 a by the processing tool 30, for example, existing data relating to the processing speed of the processing tool 30 to be used can be used. It is also possible to measure the speed and use the result.

  The control unit 50 can send a signal for adjusting the relative position of the processing tool 30 with respect to the wafer 10a, the moving speed of the processing tool 30, and the like. By these signals, the XY stage 42 and / or the scanning mechanism 44 and the like are driven. These signals are based on thickness distribution information and processing speed information, and each component is driven so as to make the thickness of the wafer 10a uniform.

  According to the numerical control processing apparatus as described above, it is possible to process at least a position where the thickness of the wafer 10a is large and reduce the thickness at the position. The processing amount can be adjusted by the scanning speed of the nozzle (processing tool 30), the nozzle diameter, the blasting pressure, the material of the abrasive, and the like. It is desirable to determine the processing conditions as appropriate in consideration of the target thickness accuracy and processing time.

3.2. Numerically Controlled Blasting Device The numerically controlled blasting device 100 of FIG. 6 adopts a blasting mode in which the processing tool 30 has a high processing speed, and can be referred to as a numerically controlled blasting device 200. The processing tool 30 of the numerically controlled blast processing apparatus 200 includes a nozzle 32, a support portion 34, and a fluid supply pipe 36. The nozzle 32 communicates with the fluid supply pipe 36 and protrudes from the support portion 34 toward the processing surface of the wafer 10a. The nozzle 32 can discharge abrasive grains from the tip. Examples of the abrasive grains include silicon carbide particles such as green carbon, silicon oxide particles, and silicon nitride particles. The abrasive grains can be discharged together with a liquid such as water (wet blasting), or can be discharged by a gas such as air or nitrogen (dry blasting). In the illustrated example, the support unit 34 is fixed to the scanning unit 46 of the scanning mechanism 44 and can move in the XY plane together with the scanning unit 46. The fluid supply pipe 36 can supply a liquid or gas containing abrasive grains to the nozzle 32. The fluid supply pipe 36 is connected to a pump or the like (not shown), and can be provided with a valve 38 for adjusting the flow rate of the fluid.

  In the case where the thickness uniformizing process is performed by the numerically controlled blast processing apparatus 200, the control unit 50 determines whether the moving mechanism 40 and the processing mechanism 40 At least one of the abrasive discharge amount can be controlled. The processing speed information of the wafer 10a by the abrasive particles discharged from the nozzle 32 is, for example, when the material of the wafer 10a, the material of the abrasive grains, the discharge amount of the abrasive grains, the discharge speed, etc. are changed in advance through experiments or the like. The processing speed of the wafer 10a can be measured and the result can be used.

  Such a numerically controlled blast processing apparatus 200 can process the wafer 10a in a short time on the basis of the thickness distribution information of the wafer 10a and the processing speed information of the wafer 10a by the abrasive particles discharged from the nozzles. This is extremely suitable for obtaining a wafer 10 with reduced variation.

3.3. Adjustment of processing amount in numerical control processing A specific method for processing at least a position where the thickness of the wafer 10a is large by numerical control processing and reducing the thickness at the position will be exemplified below.

  The numerically controlled machining apparatus 100 used for the numerically controlled machining exemplified above has at least a moving mechanism 40 and a machining tool 30. Therefore, matters that can be controlled to make the thickness of the wafer 10 a uniform include at least the moving speed of the processing tool 30 and the processing strength of the processing tool 30.

  FIG. 8 shows an example in which the thickness of the wafer 10 a is made uniform by the moving speed of the processing tool 30. In the example of FIG. 8, as indicated by the arrow, when the processing tool 30 is scanned with respect to the wafer 10a, the speed at which the wafer 10a passes through a thick part (near the center in the illustrated example) is different. It is controlled so as to be smaller than this part. At this time, if the processing strength of the processing tool 30 is constant, the processing time is longer as the thickness of the wafer 10a is larger, and more material is removed, and the thickness of the wafer 10a can be made uniform. .

  FIG. 9 shows an example in which the thickness of the wafer 10 a is made uniform according to the processing strength of the processing tool 30. In the example of FIG. 9, when the processing tool 30 is scanned with respect to the wafer 10a, the processing strength of the processing tool 30 is controlled to be higher than that of other portions when passing through a portion where the thickness of the wafer 10a is large. ing. At this time, if the scanning speed of the processing tool 30 is constant, the processing strength of the processing tool 30 increases as the thickness of the wafer 10a increases, and more material is removed, so that the thickness of the wafer 10a is uniform. Can be

  Control of the moving speed of the processing tool 30 and control of the processing strength of the processing tool 30 can be performed independently by the control unit 50, or can be performed in any combination. When only the moving speed of the processing tool 30 is controlled, it is not necessary to control the processing strength of the processing tool 30, and the scale of the numerically controlled processing apparatus 100 can be reduced.

  In the above description, the processing of the upper surface 12a of the wafer 10a has been described. However, if necessary, the wafer 10a can be turned over as shown in FIG. When the wafer 10a is turned over and the thickness uniformizing process is performed, the thickness uniformizing process may be performed after performing the above-described measurement process again using this as a new wafer 10a.

  Through the steps described above, a wafer 10 having a uniform thickness as shown in FIG. 11 is formed.

4). Other Steps The wafer processing method of this embodiment can include other steps.

  Through the “1.3. Thickness equalization step”, the work-affected layer 12 may be formed near the surface of the processing surface of the wafer 10. In such a case, a processing step of removing the work-affected layer 12 formed on the processing surface of the wafer 10 can be included after the thickness uniformizing step.

  The work-affected layer 12 may occur, for example, when blasted. In this case, the work-affected layer 12 may be a fine crack, a residual work stress, or a fine non-smooth surface. When the wafer 10 is made of quartz, the processing step can be performed by immersing the wafer 10 in an etching solution such as an aqueous hydrogen fluoride solution, an aqueous ammonium fluoride solution, or a mixed solution thereof. In this way, since the work-affected layer 12 is removed, the wafer 10 having more stable characteristics can be provided.

  The wafer processing method of the present embodiment can further include a polishing step after the “1.3. Thickness equalization step”. The polishing step can be performed by single-side polishing or double-side polishing using a disk-shaped surface plate called lapping or polishing. A polishing step can be added, for example, to further thin the wafer 10 and / or to finish the surface of the wafer 10. The wafer 10 that has undergone the thickness uniformization process has a uniform thickness. Therefore, it is possible to suppress the thickness variation and warpage of the wafer 10 in the polishing process.

  In addition, when a polishing process is added, in the thickness uniformization process, it is possible to predict the occurrence of thickness variations and warpage in the polishing process and perform numerical control processing in advance so that these can be offset. In this way, it is possible to more precisely suppress the thickness variation and warpage of the finally obtained wafer.

  As described above, according to the wafer processing method of this embodiment, it is possible to reduce variations in the thickness of the wafer before polishing in the wafer surface. Therefore, it is possible to obtain a wafer in which warpage and thickness variation are suppressed. Further, in the case of a wafer made of crystals such as quartz, it is possible to obtain a wafer having specific crystal axes aligned with respect to the normal direction of the wafer in a wide area.

  The numerically controlled blast processing apparatus of the present embodiment operates based on wafer thickness distribution information and wafer processing speed information by abrasive particles discharged from the nozzle, and can process the wafer in a short time. It is extremely suitable for obtaining a wafer with reduced resistance.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and effects). In addition, the present invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

1 ... rough, 2 ... base, 3 ... wire saw, 4 ... wire, 5 ... micrometer,
6 ... probe, 7 ... measurement point, 10, 10a ... wafer, 12a ... upper surface, 14a ... lower surface,
20 ... mounting table, 30 ... processing tool, 31 ... processing area, 32 ... nozzle, 34 ... support part,
36 ... Fluid supply pipe, 38 ... Valve, 40 ... Moving mechanism, 42 ... XY stage,
44 ... Scanning mechanism, 46 ... Scanning unit, 50 ... Control unit, 100 ... Numerical control processing device,
200 ... Numerically controlled blasting machine

Claims (7)

Preparing a wafer having a thickness distribution in-plane;
A measurement step of measuring the coordinates of a plurality of positions in the surface of the wafer and the thickness of the wafer at each of the positions, and obtaining thickness distribution information of the wafer;
Based on the thickness distribution information, at least a position having a large thickness of the wafer is processed by a numerical control processing method, and a thickness uniformizing step for reducing the thickness at the position;
Including
The wafer processing method, wherein the processing means of the numerical control processing method is blast processing. In claim 1,
The processing area of the processing means is an area having an area of 1/10000 to 1/4 of the processing surface of the wafer, and is scanned on the processing surface of the wafer. In claim 1 or claim 2,
The wafer processing method, wherein the wafer is a quartz substrate. In any one of Claims 1 to 3,
A wafer processing method including a processing step of removing a work-affected layer formed on a processing surface of the wafer after the thickness uniformizing step. In any one of Claims 1 thru | or 4,
A wafer processing method including a polishing step after the thickness uniforming step. A mounting table for mounting a wafer having a thickness distribution;
A nozzle for discharging abrasive grains to the processing surface of the wafer;
A moving mechanism that scans at least one of the mounting table and the nozzle to change the position of the nozzle with respect to the processing surface;
A control unit that controls at least one of the moving mechanism and the discharge amount of the abrasive grains based on the thickness distribution information of the wafer and the processing speed information of the wafer by the abrasive particles discharged from the nozzle;
A numerically controlled blasting machine. In claim 6,
The numerical control blasting apparatus, wherein the control mechanism controls at least a scanning speed of the moving mechanism.

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