JP2015171760A - Device and method for finish grinding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the time required for lapping and the amount of used slurry by reducing a machining allowance of lapping in a post-process, and prolong the lifetime of a grinding stone.SOLUTION: A finish grinding device (2) for finish-grinding a surface of a coarse-ground substrate (W) includes: a grinding part (10) which is rotatable and has a grinding stone (12) for grinding the substrate; a chuck (20) which is disposed opposite the grinding stone of the grinding part, and is rotatable while supporting the substrate; a grinding feed part (15) which feeds the grinding part toward the chuck along a rotary shaft thereof; and a grinding ratio changing part (30, 35) which changes a grinding ratio of the substrate to the grinding stone according to the feeding amount of the grinding part fed by the grinding feed part.

Description

  The present invention relates to a finish grinding method for finish-grinding the surface of a substrate, and more particularly to a finish grinding method for finish-grinding the surface of a rough-grinded difficult-to-cut material substrate and a finish grinding apparatus for performing such a method.

  An optical device such as a white LED is formed by laminating a nitride compound semiconductor such as gallium nitride on the surface of a sapphire substrate. With the recent increase in demand for optical devices, sapphire substrates are also widely used. In addition, the frequency of use of silicon carbide substrates is increasing as an alternative to silicon substrates.

  Since such sapphire and silicon carbide are hard, they are difficult to grind and are generally called “hard-to-cut materials”. When the surface of a substrate made of a difficult-to-cut material, such as sapphire, is roughly ground with a # 260 to # 320 grindstone, the sapphire substrate is considerably damaged more than when the silicon substrate is roughly ground.

  FIG. 6 is a partial cross-sectional view of the sapphire substrate after rough grinding. As shown in FIG. 6, the ground surface 50 after rough grinding is in a considerably rough state, and the surface roughness reaches about 3 μm (micrometer). Further, the sapphire substrate is also damaged by the thickness portion of the substrate extending from the grinding surface 50. As shown in FIG. 6, due to such damage, a polycrystalline layer 51, a mosaic layer 52, and a crack layer 53 are formed in this order on the ground surface 50 of the sapphire substrate.

  Here, a large number of cracks extending along the crystal orientation with respect to the grinding surface 50 are formed in the crack layer 53. Further, in the mosaic layer 52, random cracks are also formed on the grinding surface 50 in addition to such cracks extending along the crystal orientation. In the present specification, the layer composed of the polycrystalline layer 51, the mosaic layer 52, and the crack layer 53 is referred to as a work-affected layer 55.

  Since the work-affected layer 55 is more fragile than the rest of the substrate, if an optical device or the like is formed directly on the grinding surface 50, the base portion of the optical device or the like may be damaged. For this reason, usually, after the rough grinding, the ground surface 50 is lapped or polished to remove the work-affected layer 55.

JP 2009-285798

  However, the thickness of the work-affected layer 55 (the total thickness of the polycrystalline layer 51, the mosaic layer 52, and the crack layer 53) is relatively large, and may reach, for example, 30 um. In general, since the lapping speed is 1 um / min, a considerably long time is required to remove the entire work-affected layer 55 by lapping. Therefore, a large amount of expensive diamond slurry required for lapping work is also consumed, and the processing cost per substrate increases.

  In addition, since the lapping is controlled by the lapping time, it is difficult to precisely control the thickness of the substrate. Further, when the lapping is performed for a long time, there is a problem that the outer periphery of the substrate is sag.

  By the way, FIG. 7A is a partially enlarged view of a grinding wheel when grinding a difficult-to-cut material, and FIG. 7B is a partially enlarged view of the grinding wheel when grinding a difficult-to-cut material. As shown in these drawings, the grinding wheel is composed of a plurality of abrasive grains G and a binder F that binds the abrasive grains G to each other.

  As shown in FIG. 7A, when a substrate made of a non-hard material such as silicon is ground, the abrasive grains G that have entered below the ground surface of the substrate are detached and a self-generated blade is generated. On the other hand, when a substrate made of a difficult-to-cut material such as sapphire is ground, the rigidity of the grinding wheel and the grinding device tends to be insufficient.

  In such a case, as shown in FIG. 7 (b), the tip of the abrasive grain G near the surface of the grinding wheel wears out, and the abrasive grain G does not leave the grinding wheel, so-called self-generated blades are formed. The problem of not occurring occurs. When the tips of the abrasive grains G in the vicinity of the surface of the grinding wheel are worn, the number of working abrasive grains that come into contact with the substrate increases, leading to an increase in grinding temperature and occurrence of surface burn. Therefore, when grinding a substrate made of a difficult-to-cut material, a grindstone configuration that extremely reduces the grinding ratio is necessary. When the grinding ratio is low, the life of the grinding wheel is significantly reduced.

  The problems related to the increase in processing cost per substrate and surface sagging of the outer peripheral portion of the substrate can be solved by reducing the machining allowance (thickness of the work-affected layer 55 to be removed) in lapping. Therefore, it is also conceivable to finish-grind the substrate after rough grinding. However, conventional grinding methods have not solved the problems of insufficient rigidity of the grinding wheel and the like and the reduction in the life of the grinding wheel, and have not yet achieved finish grinding.

  The present invention has been made in view of such circumstances, and a finishing grinding method and such a method capable of reducing the time required for lapping and the amount of diamond slurry used by reducing the machining allowance in lapping. An object of the present invention is to provide a finish grinding apparatus that implements the above.

In order to achieve the above-mentioned object, according to the first invention, in a finish grinding apparatus for finish grinding a surface of a roughly ground substrate, a rotatable grinding unit provided with a grinding wheel for grinding the substrate, A chuck that is disposed to face the grinding wheel of the grinding part and is rotatable while holding the substrate; a grinding feed part that feeds the grinding part toward the chuck along its rotation axis; A grinding ratio changing unit that changes a grinding ratio of the substrate with respect to the grinding wheel according to a feed amount that the grinding feeding unit feeds the grinding unit, and the grinding ratio changing unit includes the grinding unit A dressing member arranged to face the grinding wheel, and a pressing mechanism for changing the pressure for pressing the dressing member against the grinding wheel according to the feed amount, or the dressing member according to the time for finishing grinding the substrate The above And a pressing mechanism for varying the pressure for pressing the cutting grindstone, fine grinding device is provided.

A work-affected layer composed of a plurality of layers is formed on the surface of the substrate after the rough grinding, and the thickness of each layer in the work-affected layer can be grasped in advance by experiments or the like. In the first invention, since the grinding ratio can be changed according to the feed amount of the grinding part, the life of the grinding wheel can be lengthened, and appropriate grinding according to each layer in the work-affected layer can be performed. As a result, the work-affected layer on the surface of the substrate after the finish grinding can be made considerably thinner than the work-affected layer after the rough grinding, and therefore the machining allowance in the lapping finish in the subsequent process can be reduced. Therefore, the time required for lapping and the amount of diamond slurry used can be reduced. Furthermore, in the first invention, the grinding ratio can be easily changed while grinding the substrate by changing the pressing pressure for pressing the dress member against the grinding wheel in accordance with the feed amount. In addition, the chuck is arranged to face the grinding wheel in the area about half or less of the surface of the grinding part, and the dressing member is arranged to face the grinding wheel in the remaining area of the surface of the grinding part. preferable. Furthermore, in the first invention, the grinding ratio can be easily changed while grinding the substrate by changing the pressing pressure for pressing the dress member against the grinding wheel according to time. In addition, it is preferable that the chuck is disposed to face the grinding wheel in a region about half of the surface of the grinding part, and the dress member is disposed to face the grinding wheel in the remaining region of the surface of the grinding part. Further, when the finish grinding apparatus operates based on a program in which the feed rate changes according to the time from the start of feeding, the grinding ratio is changed based on the time and the feed rate.

According to a second invention , in the first invention, a work-affected layer composed of a plurality of types of layers is formed on the surface of the substrate that has been coarsely ground, and the pressing mechanism portion is provided on the surface of the substrate. The pressure was changed in accordance with the layer of the work-affected layer located in the area.
That is, in the second invention, appropriate grinding according to each layer in the work-affected layer can be performed.

According to a third aspect of the present invention, in the finish grinding method of finish grinding the surface of the rough ground substrate, the grinding portion provided with the grinding wheel for grinding the substrate is rotated so that the grinding portion of the grinding portion faces the grinding wheel. The chuck for holding the substrate is rotated, the grinding part is fed toward the chuck along its rotation axis, and the grinding wheel is applied to the grinding wheel according to the feed amount fed to the grinding part. The grinding ratio of the substrate is changed, and the pressure for pressing the dressing member disposed facing the grinding wheel of the grinding portion against the grinding wheel is changed according to the feed amount or the time for finishing grinding the substrate. Thus, a finish grinding method is provided in which the grinding ratio of the substrate is changed .

A work-affected layer composed of a plurality of layers is formed on the surface of the substrate after the rough grinding, and the thickness of each layer in the work-affected layer can be grasped in advance by experiments or the like. In the third aspect of the invention, the grinding ratio can be changed according to the feed amount of the grinding part, so that the life of the grinding wheel can be lengthened and appropriate grinding according to each layer in the work-affected layer can be performed. As a result, the work-affected layer on the surface of the substrate after the finish grinding can be made considerably thinner than the work-affected layer after the rough grinding, and therefore the machining allowance in the lapping finish in the subsequent process can be reduced. Therefore, the time required for lapping and the amount of diamond slurry used can be reduced. Furthermore, the grinding ratio can be easily changed while grinding the substrate by changing the pressing pressure for pressing the dress member against the grinding wheel according to the feed amount or time. In addition, the chuck is arranged to face the grinding wheel in the area about half or less of the surface of the grinding part, and the dressing member is arranged to face the grinding wheel in the remaining area of the surface of the grinding part. preferable. Further, it is preferable that the chuck is disposed facing the grinding wheel in a region about half of the surface of the grinding portion, and the dressing member is disposed facing the grinding wheel in the remaining region of the surface of the grinding portion. Further, when the finish grinding apparatus operates based on a program in which the feed rate changes according to the time from the start of feeding, the grinding ratio is changed based on the time and the feed rate.

According to a fourth aspect, in the third aspect , a work-affected layer comprising a plurality of types of layers is formed on the surface of the rough ground substrate, and the work-affected layer located on the surface of the substrate. The pressure was changed according to the layer.
That is, in the fourth invention, appropriate grinding according to each layer in the work-affected layer can be performed.

According to a fifth aspect, in the third aspect, in the grinding process, constantly monitoring the load to the grindstone spindle, by indirectly grasp the status of the abrasive surface, depending on its state grinding The ratio was changed.
That is, in the fifth aspect, by appropriately grasping the state of the grinding surface by the load of the grindstone rotating shaft, it is possible to perform appropriate grinding according to the state of the grinding surface while grinding the substrate.

According to the sixth aspect, in the third aspect, further comprising a detector for detecting the thickness of the substrate is ground finish in real time, which is disposed facing to the grinding wheel of the grinding part The grinding ratio of the substrate is changed by changing the pressure for pressing the dress member against the grinding wheel according to the thickness or the machining allowance of the substrate detected by the detection unit.
That is, in the sixth aspect of the invention, by changing the pressing pressure for pressing the dressing member against the grinding wheel in accordance with the thickness of the substrate or the machining allowance, the grinding ratio can be changed easily and accurately while grinding the substrate. be able to. The detection unit is preferably two in-process gauges that can be installed on the surface of the chuck and the upper surface of the substrate.

It is a figure which shows the process flow when grinding a difficult-to-cut material board | substrate in this invention. It is a side view of the finish grinding apparatus based on this invention. FIG. 3 is a partial cross-sectional view of the finish grinding apparatus shown in FIG. 2. It is a bottom view of the grinding part in the finish grinding apparatus shown by FIG. It is a figure which shows time charts, such as a grindstone axis | shaft rotation speed. It is a fragmentary sectional view of a sapphire substrate after rough grinding. (A) It is the elements on larger scale of the grinding wheel when grinding a difficult-to-cut material. (B) It is the elements on larger scale of the grinding wheel when grinding a difficult-to-cut material. It is a side view of the finish grinding device in other embodiments of the present invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following drawings, the same members are denoted by the same reference numerals. In order to facilitate understanding, the scales of these drawings are appropriately changed.
FIG. 1 is a diagram showing a process flow when grinding a difficult-to-cut material substrate in the present invention. As shown in FIG. 1, when grinding a difficult-to-cut material, for example, a substrate W made of sapphire or silicon carbide (hereinafter simply referred to as “substrate W”) in the present invention, first, rough grinding is performed with a horizontal grinder 1. Then, finish grinding is performed by the finish grinding apparatus 2 according to the present invention, and finally lapping is performed by the lapping machine 3.

  As can be seen with reference to FIG. 6, when the substrate W is roughly ground under a predetermined condition by the grinding wheel (counter # 260 to # 320) of the horizontal grinding machine 1, the polycrystalline layer 51, the mosaic layer 52, and the crack layer 53. A work-affected layer 55 is formed on the grinding surface 50 of the substrate W. In the present invention, before such a substrate W is lapped, the finish grinding apparatus 2 performs finish grinding.

  FIG. 2 is a side view of a finish grinding apparatus according to the present invention. 3 is a partial cross-sectional view of the finish grinding apparatus shown in FIG. 2, and FIG. 4 is a bottom view of a grinding portion in the finish grinding apparatus shown in FIG.

  As shown in FIG. 2, the finish grinding apparatus 2 includes a grinding unit 10 that can rotate around the grindstone shaft 11. A plurality of grinding wheels 12 for grinding the substrate W are attached to the bottom surface of the grinding unit 10. In the embodiment shown in FIG. 4, eight elongated grinding wheels 12 extend at equal intervals in the radial direction of the grinding part 10. It should be noted that the shape and the number of grinding wheels 12 are not limited to the shape shown in FIG.

  As is well known, these grinding wheels 12 are composed of a plurality of abrasive grains G and a binder F that binds these abrasive grains G to each other (see FIG. 7). Further, the count of the grinding wheel 12 in the finish grinding apparatus 2 is, for example, # 1000 to # 2000.

  Referring again to FIG. 2, a chuck 20 that holds at least one substrate W (three substrates W in the drawing) is disposed facing the grinding wheel 12 of the grinding unit 10. The chuck 20 can rotate around the chuck shaft 21 shown in FIG. As can be seen from FIG. 4, the chuck 20 is disposed at a position corresponding to a part off the center of the surface of the grinding part 10 and cannot be detached from the outer periphery of the grinding part 10 beyond the radius of the chuck. The diameter of the chuck 20 is preferably equal to or less than the length of the grinding wheel 12. Further, as shown in FIG. 2, the chuck 20 is moved from a lower position of the grinding unit 10 to a far-out take-out position by the transport system 25.

  Further, the dress member 30 is arranged to face the grinding wheel 12 at a position corresponding to another part off the center of the surface of the grinding part 10. The dress member 30 is configured to rotate around the dress shaft 31. The dress member 30 is made of a material having a lower hardness than the grinding wheel 12, for example, white alumina. The dress member 30 may be formed of another material having a hardness lower than that of the grinding wheel 12.

  As shown in FIG. 3, the dress member 30 is connected to the pressing mechanism unit 35, and the dress member 30 is configured to be pressed against the grinding wheel 12 of the grinding unit 10 according to the operation of the pressing mechanism unit 35. Yes. In other words, the pressing pressure with which the dress member 30 is pressed against the grinding unit 10 is controlled by the pressing mechanism unit 35. As can be seen from FIG. 4, the diameter of the dress member 30 is preferably longer than the length of the grinding wheel 12.

  When the dressing member 30 is pressed against the grinding wheel 12 by the pressing mechanism 35, the abrasive grains G of the grinding wheel 12 are detached from the grinding wheel 12, and a self-generated blade is generated. As a result, the ratio of the grinding amount of the substrate W to the wear amount of the grinding wheel 12 (hereinafter referred to as “grinding ratio”) decreases. When the pressing pressure is further increased, the grinding wheel 12 is further worn. That is, the dress member 30 and the pressing mechanism portion 35 in the present invention serve as a grinding ratio changing portion.

  Referring to FIG. 2 again, the grinding part 10 is connected to the nut 16 of the ball screw 15 via the connecting part 13. When the motor 18 is rotated, the nut 16 of the ball screw 15 moves up and down along the screw shaft 17. As a result, the grinding part 10 is moved toward the chuck 20 along the grindstone shaft 11. For this reason, in the following, the ball screw 15 may be referred to as a grinding feed portion 15.

  Further, the finish grinding apparatus 2 includes a control unit 40 that controls the entire operation of the finish grinding apparatus 2. The control unit 40 is a digital computer and controls operations of the grindstone shaft 11, the chuck shaft 21, the dressing shaft 31, the pressing mechanism unit 35, and the motor 18. Further, the control unit 40 includes an operation program for operating the finish grinding apparatus 2. In addition, the control unit 40 can serve as a time measuring unit that measures an elapsed time after the operation of the finish grinding apparatus 2 starts.

  FIG. 5 is a diagram showing a time chart of the grindstone shaft rotation speed and the like. Hereinafter, the operation of the finish grinding apparatus 2 of the present invention will be described with reference to FIG. Note that the sections A, B, and C shown in FIG. 5 are times corresponding to the thicknesses A ′, B ′, and C ′ of the polycrystalline layer 51, the mosaic layer 52, and the crack layer 53 shown in FIG. Represents.

  In addition, before the operation of the finish grinding apparatus 2 is started, the chuck 20 holding the substrate W roughly ground by the horizontal grinding machine 1 is positioned below the grinding unit 10 shown in FIG. Shall. Since the rough grinding process by the horizontal grinder 1 is performed under predetermined conditions, the thicknesses A ′ and B of the polycrystalline layer 51, the mosaic layer 52, and the crack layer 53 in the work-affected layer 55 formed by the rough grinding, respectively. It is assumed that “, C” has been previously grasped by an experiment or the like and stored in the control unit 40.

  The lengths of sections A, B, and C shown in FIG. 5 are determined based on a grindstone feed speed and thicknesses A ′, B ′, and C ′, which will be described later. When the finish grinding apparatus 2 is operated in accordance with an operation program in which the grinding wheel feed speed changes, the sections A, B, and A are based on the grinding wheel feed speed and the thicknesses A ′, B ′, and C ′ corresponding to the sections. The length of C is determined. These sections are also stored in the control unit 40.

  At the start of the operation of the finish grinding apparatus 2, the control unit 40 rotates the grindstone shaft 11, the screw shaft 17, and the chuck shaft 21 respectively at a predetermined high rotational speed. As a result, the grinding unit 10 is fed toward the chuck 20 at a grindstone feed rate determined according to the number of rotations of the screw shaft 17.

  Thereby, only the polycrystalline layer 51 of the work-affected layer 55 is removed from the ground surface 50 of the substrate W in the section A in FIG. In other words, the rotational speeds of the grindstone shaft 11, the screw shaft 17 and the chuck shaft 21 are set so that only the polycrystalline layer 51 is removed in the section A. Since the polycrystalline layer 51 is more fragile than the portion of the substrate W other than the work-affected layer 55, the grinding ratio in the section A is large. As can be seen from FIG. 5, when the finish grinding apparatus 2 starts to operate, the dress shaft 31 and the pressing mechanism 35 are not operating.

  When the grinding unit 10 is fed by the thickness A ′ of the polycrystalline layer 51 corresponding to the section A, the control unit 40 changes the rotational speeds of the grindstone shaft 11, the screw shaft 17 and the chuck shaft 21 in the section B. Lower than in the case of section A. At the same time, the dress member 30 is rotated around the dress axis 31 at a predetermined high rotational speed, and the pressing mechanism 35 is activated to press the dress member 30 against the grinding wheel 12 with a predetermined low pressing pressure. Therefore, as shown in FIG. 5, the grinding ratio in the section B is lower than the grinding ratio in the section A.

  Under such a grinding condition, only the mosaic layer 52 of the work-affected layer 55 is removed from the substrate W in the section B. In other words, the rotational speed of the grindstone shaft 11, the screw shaft 17 and the chuck shaft 21, the rotational speed of the dress shaft 31, and the pressing pressure of the dress member 30 are set so that only the mosaic layer 52 is removed in the section B. .

  In the section B, the dressing member 30 is pressed against the grinding wheel 12, so the grinding wheel 12 is dressed by the dressing member 30 while grinding the substrate W. Accordingly, the tips of the abrasive grains of the grinding wheel 12 (see FIG. 7) do not wear, and the abrasive grains of the grinding wheel 12 are appropriately detached from the grinding wheel 12. As a result, the grinding wheel 12 is self-generated.

  In general, when the mosaic layer 52 of the difficult-to-cut material base W is ground, the tip of the abrasive grains in the grinding wheel 12 is worn and it is difficult to generate a self-generated blade. Therefore, the mosaic layer 52 is ground in the polycrystalline layer 51. More difficult than grinding. However, in the present invention, since the grinding wheel 12 is dressed simultaneously with the grinding of the substrate W, a self-generated blade is generated in the grinding wheel 12. Therefore, even when the base material W made of a difficult-to-cut material is ground, the mosaic layer 52 of the difficult-to-cut material substrate W can be easily removed with low damage. Therefore, in the present invention, it is possible to suppress an increase in grinding temperature and occurrence of surface burn.

  Note that the amount of wear of the grinding wheel 12 is reduced by lowering the rotation speed of the chuck shaft 21. However, when the number of rotations of the chuck shaft 21 is lowered, the surface roughness of the grinding surface increases, so that the number of rotations of the chuck shaft 21 is constant over the sections A to C shown in FIG. Good.

  When the grinding unit 10 is fed by the thickness B1 of the mosaic layer 52 corresponding to the section B, the control unit 40 sets the rotational speed of the grindstone shaft 11, the screw shaft 17 and the chuck shaft 21 in the section C in the section B. Each further down. Then, the dress member 30 is rotated around the dress shaft 31 at a predetermined low rotational speed, and the dress member 30 is pressed against the grinding wheel 12 with a predetermined high pressing pressure. Therefore, as shown in FIG. 5, the grinding ratio in the section C is further lowered than the grinding ratio in the section B.

  Under such grinding conditions, in the section C, only the crack layer 53 of the work-affected layer 55 is removed from the substrate W. In other words, the rotational speed of the grindstone shaft 11, the screw shaft 17 and the chuck shaft 21, the rotational speed of the dress shaft 31, and the pressing pressure of the dressing member 30 are set so that only the crack layer 53 is removed in the section C. .

  Although the crack layer 53 is harder to grind than the mosaic layer 52, the grinding wheel 12 further has a self-generated blade for the same reason as described above. Therefore, in the present invention, the crack layer 53 of the difficult-to-cut material substrate W can be easily removed with low damage without increasing the grinding temperature and without causing surface burn.

  When the grinding part 10 is fed by the thickness C ′ of the crack layer 53 corresponding to the section C, the crack layer 53 is removed. Thereafter, the chuck 20 is transported from the lower position of the grinding unit 10 to the far-off extraction position by the transport system 25 (see FIG. 2). Then, the substrate W is removed from the chuck 20 and lapped by the lapping machine 3 shown in FIG.

  As described above, in the present invention, the grinding ratio of the grinding wheel 12 is changed according to the feed amount of the grinding part 10. Therefore, although the work-affected layer 55 is also formed on the substrate W that has been finish-ground by the finish grinding apparatus 2, the work-affected layer 55 after finish grinding can be considerably smaller than the work-affected layer 55 after rough grinding. In a certain embodiment, the thickness of the work-affected layer 55 formed after finish grinding by the finish grinding apparatus 2 is about 5 μm or less.

  That is, in the present invention, the machining allowance by the lapping machine 3 can be considerably reduced as compared with the case of lapping without using the finish grinding apparatus 2. For this reason, in this invention, compared with the case of a prior art, the time which a lapping finish requires can be reduced significantly. As a result, the amount of diamond slurry used for lapping can be reduced. In addition, since the time required for the lapping is short, the thickness control of the lapped substrate W is relatively easy, and the occurrence of surface sag at the outer peripheral portion of the substrate W can be suppressed.

  In the embodiment with reference to the drawings, the grinding ratio is changed by the pressing mechanism 35 pressing the dress member 30 or the like. However, it will be apparent to those skilled in the art that other means that can change the grinding ratio can be used.

  FIG. 8 is a side view of a finish grinding apparatus according to another embodiment of the present invention. In FIG. 8, the chuck 20 holds a single substrate W. This substrate W is larger than the substrate W shown in FIG. 2 and its diameter is shorter than the length of one grinding wheel 12. For this reason, as shown in the drawing, a part of the substrate W held by the chuck 20 protrudes from the lower surface of the grinding part 10.

  As can be seen from FIG. 8, at the edge of the upper surface of the chuck 20, there is an annular region where the substrate W is not present and the upper surface is exposed. The tip end of the first in-process gauge 61 extending in a cantilever manner from a fixed portion (not shown) is in contact with this annular region. Similarly, the tip of the second in-process gauge 62 extending in a cantilever manner is in contact with the upper surface of the substrate W.

  These in-process gauges 61 and 62 are connected to the calculation unit 60 and serve as contact sensors. The calculation unit 40 calculates the deviation between the detection values of the two in-process gauges 61 and 62 as the thickness of the substrate W. The calculation unit 40 can also calculate a value obtained by subtracting the detection value of the first in-process gauge 61 from the thickness of the substrate W before finish grinding as the machining allowance of the substrate W. In the present invention, since such in-process gauges 61 and 62 are provided, the substrate W is ground until a desired thickness or a desired machining allowance is obtained while constantly monitoring the thickness of the substrate W in-process. can do.

  Therefore, in the embodiment shown in FIG. 8, the pressure for pressing the dressing member 30 against the grinding wheel 12 is changed according to the thickness or machining allowance of the substrate W detected in real time, thereby grinding the substrate W. The ratio can be changed. Therefore, in this case as well, it will be understood that the grinding ratio is changed according to the type of layer in the work-affected layer, and as a result, the same effect as described above can be obtained.

DESCRIPTION OF SYMBOLS 1 Horizontal grinding machine 2 Finish grinding machine 3 Lapping machine 10 Grinding part 11 Grinding wheel axis | shaft 12 Grinding wheel 13 Connection part 15 Ball screw (grinding feed part)
16 Nut 17 Screw shaft 18 Motor 20 Chuck 21 Chuck shaft 25 Transfer system 30 Dressing member (grinding ratio changing section)
31 Dressing shaft 35 Pressing mechanism (grinding ratio changing part)
40 Control Unit 50 Grinding Surface 51 Polycrystalline Layer 52 Mosaic Layer 53 Crack Layer 55 Work Altered Layer 60 Calculation Unit 61, 62 In-process Gauge (Detection Unit)
F binder G abrasive W substrate

Claims (10)

In a finish grinding apparatus that finish-grinds the surface of a roughly ground substrate,
A grinding part that includes a grinding wheel for grinding the substrate and is rotatable;
A chuck that is disposed facing the grinding wheel of the grinding part and is rotatable while holding the substrate;
A grinding feed section for feeding the grinding section toward the chuck along its rotational axis;
A finish grinding apparatus comprising: a grinding ratio changing unit that changes a grinding ratio of the substrate to the grinding wheel in accordance with a feed amount that the grinding feeding unit feeds the grinding unit.   The grinding ratio changing unit includes a dressing member arranged to face the grinding wheel of the grinding unit, and a pressing mechanism unit that changes a pressure for pressing the dressing member against the grinding wheel according to the feed amount. The finish grinding apparatus according to claim 1, further comprising:   The grinding ratio changing unit includes a dressing member arranged to face the grinding wheel of the grinding unit, and a pressing force that changes a pressure for pressing the dressing member against the grinding wheel according to a time for finish grinding the substrate. The finish grinding apparatus according to claim 1, comprising a mechanism portion. On the rough ground surface of the substrate, a work-affected layer consisting of a plurality of types of layers is formed,
The finish grinding apparatus according to claim 2 or 3, wherein the pressing mechanism section changes the pressure in accordance with a layer of the work-affected layer located on the surface of the substrate. In the finish grinding method of finish grinding the surface of the rough ground substrate,
Rotating a grinding part provided with a grinding wheel for grinding the substrate,
It is arranged facing the grinding wheel of the grinding part, and a chuck for holding the substrate is rotated,
Feeding the grinding part along the rotation axis toward the chuck;
A finish grinding method in which a grinding ratio of the substrate to the grinding wheel is changed according to a feed amount for feeding the grinding part.   The grinding ratio of the substrate is changed by changing a pressure for pressing a dressing member arranged to face the grinding wheel of the grinding unit against the grinding wheel according to the feed amount. 5. The finish grinding method according to 5.   The grinding ratio of the substrate is changed by changing the pressure for pressing the dressing member arranged facing the grinding wheel of the grinding portion against the grinding wheel according to the time for finishing grinding the substrate. The finish grinding method according to claim 5. On the rough ground surface of the substrate, a work-affected layer consisting of a plurality of types of layers is formed,
The finish grinding method according to claim 6 or 7, wherein the pressure is changed according to the layer of the work-affected layer located on the surface of the substrate.   The grinding ratio of the substrate is changed by changing the pressure that presses the dressing member disposed facing the grinding wheel of the grinding unit against the grinding wheel according to the load applied to the rotating shaft of the grinding wheel. The finish grinding method according to claim 5. Furthermore, it comprises a detection unit that detects in real time the thickness at which the substrate is finish-ground,
By changing the pressure for pressing the dressing member arranged facing the grinding wheel of the grinding unit against the grinding wheel according to the thickness or the machining allowance of the substrate detected by the detection unit, The finish grinding method according to claim 5, wherein the grinding ratio is changed.

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