JP4149295B2 - Lapping machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lapping machine for lapping the upper and lower surfaces of a wafer, and more particularly to a lapping machine for optimizing the amount of abrasive grains supplied to a wafer during lapping.
[0002]
[Prior art]
A general manufacturing method of a mirror wafer used as a raw material wafer for manufacturing a semiconductor device will be described. First, a single crystal semiconductor ingot is grown by the Czochralski method (CZ method), the floating zone melting method (FZ method), or the like. Since the outer shape of the grown semiconductor ingot is distorted, the outer shape of the semiconductor ingot is then ground by a cylindrical grinder or the like in the external grinding process to adjust the outer shape of the semiconductor ingot. This is sliced with a wire saw or the like in the slicing step and processed into a disk-shaped wafer having a thickness of about 500 to 1000 μm, and then the wafer peripheral portion is chamfered in the chamfering step.
[0003]
After that, a flattening process is performed by a lapping process, and after a primary polishing and a secondary polishing through an etching process, an epitaxial growth process is performed on the wafer surface to obtain a mirror wafer.
[0004]
In order to produce a semiconductor device by forming a circuit on the surface of a mirror surface wafer obtained through such a process, extremely high flatness is required in recent high-precision device production. That is, when the surface flatness of the wafer is low, the lens is not partially focused during exposure in the photolithography process, which causes a problem that it is difficult to form a fine pattern of the circuit.
[0005]
On the other hand, not only the semiconductor wafer described above but also a material to be polished having a flat surface such as a liquid crystal substrate is required to have a flat surface.
[0006]
However, the thickness of a sliced wafer is not always constant, and the surface has irregularities, so that the lapping step described above is performed to remove this. FIG. 7 is a longitudinal sectional view showing a schematic structure of a conventional general lapping machine 50, and FIG. 8 is an enlarged longitudinal sectional view of a main part of the prior art lapping machine. A general semiconductor wafer lapping process will be described with reference to FIG.
[0007]
The lapping machine 50 used in the lapping process holds the upper surface plate 57 and the lower surface plate 58 that form an annular shape when viewed from above, in parallel with the polished surfaces facing each other as shown in FIG. A carrier 60 is arranged between them. The carrier 60 has a substantially disc shape, and has a plurality of through-loading holes for accommodating the wafer 30 on the plate surface. Then, the carrier 60 is rotated relative to the upper surface plate 57 and the lower surface plate 58 while the wafer 30 is accommodated in the loading hole, and a slurry mixed with abrasive grains is supplied to the upper surface of the carrier 60. , 58 and the wafer 30. Thereby, the wafer 30 and the upper surface plate 57 and the lower surface plate 58 slide relative to each other, and the surface of the wafer 30 is scraped and polished.
[0008]
In general, since the lapping machine supplies slurry from the upper surface of the carrier 60, there is a problem that the slurry is insufficient on the lower surface of the carrier 60, that is, the lower surface of the wafer 30, and scratches are generated on the lower surface of the wafer 30.
[0009]
In order to solve this, for example, as disclosed in Japanese Patent Laid-Open No. 10-180623, a hole is formed in the carrier 60, and the slurry between the upper surface plate 57 and the carrier 60 is supplied to the lower surface of the carrier 60. Some lapping machines make it easier. According to this lapping machine, the shortage of abrasive grains on the lower surface plate side can be compensated, and scratches generated on the lower surface of the wafer can be prevented.
[0010]
[Problems to be solved by the invention]
However, in the lapping machine according to such a conventional technique, during polishing of the wafer, as shown in FIG. 8, the abrasive grains 35 are placed in a region 47 indicated by a broken line sandwiched between the wafer 30, the upper surface plate 57 and the carrier 60. It was involved excessively. In the figure, the arrows indicate the moving directions of the upper and lower surface plates 57, 58, the wafer 30, the carrier 60, and the abrasive grains 35. Therefore, there is a problem that the wafer outer peripheral portion upper surface 30a is excessively polished due to excessive concentration of abrasive grains 35 on the wafer outer peripheral portion upper surface 30a, and surface sagging occurs.
[0011]
That is, the lapping machine disclosed in Japanese Patent Laid-Open No. 10-180623 is simply a hole for making up for the shortage of abrasive grains on the lower surface plate side and preventing scratches generated on the lower surface of the wafer. A hole having a shape was processed in the carrier, but the shape and dimensions for the purpose of improving the flatness were not determined. Therefore, the wafer was excessively polished on the wafer outer peripheral portion upper surface 30a.
[0012]
On the other hand, if the amount of slurry to be supplied is simply reduced to prevent excessive concentration of abrasive grains 35 on the wafer outer peripheral surface 30a, there is a problem that scratches are generated on the wafer surface.
[0013]
The invention according to the present application has been made to solve the above-described problems, and the object of the invention is to optimize the amount of abrasive grains supplied to the processing point during lapping processing, It is an object of the present invention to provide a lapping machine capable of drawing the abrasive particles excessively wound on the lower surface plate side and making the shape of the upper surface of the wafer outer peripheral portion closer to flat.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a first invention according to the present application is arranged between an upper surface plate and a lower surface plate arranged to face each other in parallel, and between the upper surface plate and the lower surface plate. And a carrier having a loading hole for holding a workpiece, wherein a slurry containing abrasive grains is supplied to the workpiece, wherein the carrier is supplied to the workpiece. A lapping machine comprising means for removing excessive abrasive grains.
[0015]
In addition, a second invention according to the present application is the lapping machine according to the first invention, wherein the removing means is an abrasive hole penetrating from the upper surface to the lower surface of the carrier. .
[0016]
Furthermore, the third invention according to the present application is characterized in that the abrasive grain removal hole is provided in the range of 2 to 10 mm close to the outer periphery of the loading hole. It is a lapping machine as described in.
[0017]
Moreover, 4th invention which concerns on this application is a lapping machine as described in the said 2nd or 3rd invention, wherein the said abrasive grain extraction hole is circular arc shape.
[0018]
Further, a fifth invention according to the present application is the lapping machine according to any one of the second to fourth inventions, wherein the abrasive grain punching hole has a width of 5 mm or more.
[0019]
According to a sixth aspect of the present invention, in the first aspect, the means for removing is a hollow portion in which the carrier member around the loading hole is deformed so as to wave up and down. It is a lapping machine as described in the invention.
[0020]
Furthermore, a seventh invention according to the present application is arranged between an upper surface plate and a lower surface plate arranged to face each other in parallel, and between the upper surface plate and the lower surface plate, and holds a workpiece. And a carrier having a loading hole for supplying a slurry containing abrasive grains to the workpiece, wherein a concave or convex portion is provided on the surface of the carrier. It is a lapping machine.
[0021]
An eighth invention according to the present application is the lapping machine according to the seventh invention, wherein the concave portion or the convex portion is provided so as to surround an outer periphery of the loading hole.
[0022]
Furthermore, a ninth invention according to the present application is the lapping machine according to any one of the first to eighth inventions, wherein the workpiece is a thin plate-like body.
[0023]
A tenth invention according to the present application is the lapping machine according to any one of the first to eighth inventions, wherein the workpiece is a silicon wafer.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. However, the materials, dimensions, shapes, relative positions, and the like of the component parts described in the following embodiments are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only. Further, in the following embodiments, a case where a silicon wafer is polished is described as a specific example, but the present invention is not limited to this, and a thin plate-like body such as various semiconductor substrates and liquid crystal glass substrates. Needless to say, this can also be applied to.
[0025]
1 is a longitudinal sectional view showing a schematic structure of a lapping machine 1 according to the present invention. FIG. 2 (a) is a bottom view of an upper surface plate 19, FIG. 2 (b) is a plan view of a lower surface plate 31, FIG. (A) is a plan view showing a rotation mechanism of the carrier 41 according to the present invention, FIG. 3 (b) is a plan view of the carrier 41, FIG. 4 is an enlarged vertical sectional view of the main part of the lapping machine 1, and FIG. The principal part expansion perspective view which shows the modification 1 of the carrier 41 concerning this invention, FIG.5 (b) is a principal part expansion longitudinal cross-sectional view, Fig.6 (a) is a principal which shows the modification 2 of the carrier 41 concerning this invention. FIG. 6B is an enlarged vertical sectional view of a main part.
[0026]
As shown in FIG. 1, a sub-cylinder 12 is connected in series to the lower end of a rod 11a of a main cylinder 11 arranged vertically downward. The rod 11a of the main cylinder 11 is connected to the sub cylinder 12, and the main cylinder 11 and the sub cylinder 12 can extend and contract independently. The main cylinder 11 controls the vertical movement of the upper surface plate 19 in order to replace the wafer 30 with a new wafer to be lapped when lapping the wafer 30 is completed.
[0027]
On the other hand, the sub-cylinder 12 has a function of controlling the load applied to the wafer 30 from the upper surface plate 19 and always applies a force in the direction of lifting the upper surface plate 19. A disk-shaped lifting plate 13 having an outer diameter of about 1100 to 1400 mm is fixed to the lower end of the rod 12a of the sub cylinder 12. A through hole 15 c is formed in the vicinity of the outer periphery of the lifting plate 13. A washer 15b is placed on the through hole 15c, and a bolt 15a is inserted from above through the washer 15b and the through hole 15c.
[0028]
The bolt 15a is made of chromium-molybdenum steel, has a cylindrical shape, and has a male screw at the lower end. The male screw at the lower end of the bolt 15 a is screwed into a female screw provided on the upper surface plate 19 to support the upper surface plate 19.
[0029]
The upper surface plate 19 has a thick cylindrical shape with a lower surface having an outer diameter of 1800 mm and an inner diameter of 730 mm, and has a weight of about 1000 kg. In order to increase the lapping efficiency, it is important to make the distribution of the abrasive grains 35 uniform, so the upper surface plate 19 is made of spheroidal graphite cast iron in which spheroidal graphite is uniformly dispersed, Graphite is functioning as a holding site for abrasive grains.
[0030]
On the other hand, a lower surface plate receiver 32 made of aluminum having a width of 100 mm in the radial direction of the lower surface plate 31 and a length of about 500 mm in the circumferential direction is fixed on the bracket 23. Twelve lower surface plate receivers 32 are arranged radially, and the lower surface plate 31 holds the lower surface plate 31 in parallel with the upper surface plate 19. The material of the lower surface plate 31 is spheroidal graphite cast iron for the same reason as the upper surface plate 19, and the outer diameter is 1800 mm.
[0031]
The upper surface plate 19 is provided with 45 slurry supply holes 33 for supplying abrasive grains 35. The slurry supply hole 33 is connected to a slurry supply tank (not shown) by a vinyl hose or the like. The slurry supply tank stores aqueous or oily slurry supplied to the upper surface plate 19 and the lower surface plate 31 during lapping. The slurry in the slurry supply tank is supplied between the wafer 30 and the upper surface plate 19 and the lower surface plate 31 through the slurry supply hole 33 during lapping.
[0032]
The slurry stored in the slurry supply tank is called a lapping slurry, which is a water-soluble mixture of free abrasive grains having an average particle size of about 11 to 12 μm, such as alumina and zirconium, and water containing a surfactant. A slurry or the like can be used. Various materials such as aluminum oxide and silicon carbide can be used as the raw material for the free abrasive grains.
[0033]
On the other hand, as shown in FIGS. 2 (a) and 2 (b), wrapping grooves 34 for allowing abrasive grains 35 to escape are provided on the wrapping surfaces 19a, 31a of the upper and lower surface plates 19, 31. The width of the wrapping groove 34 is not particularly limited, but is, for example, 1.5 mm to 2 mm, preferably 2 mm. Moreover, although the space | interval of the wrapping groove 34 and the wrapping groove 34 is not specifically limited, For example, 10 mm-50 mm, Preferably it is 30 mm. Further, the depth of the wrapping groove 34 is not particularly limited, but is, for example, 18 mm to 25 mm, preferably 25 mm.
[0034]
The abrasive grains 35 supplied between the slurry supply hole 33 and the upper and lower surface plates 19 and 31 are supplied to the wafer surface via the lapping grooves 34. Further, used slurry and wafer grinding debris are discharged from the lapping surfaces 19a and 31a via the lapping grooves 34.
[0035]
On the other hand, FIG. 3A is a schematic view schematically showing the carrier rotation mechanism of the lapping machine 1. As shown in FIG. 3A, a carrier 41 having a diameter of about 650 mm and a thickness of about 700 to 750 μm is provided between the upper surface plate 19 and the lower surface plate 31, and a sun gear 45 provided at the center of the lower surface plate 31 is the center. As shown in FIG. Each carrier 41 is made of SK5 tool steel or SUS, and has seven circular loading holes 42 each having a diameter of 201 mm for accommodating a wafer 30 having a diameter of 200 mm on the plate surface.
[0036]
A planet gear 43 is provided on the outer periphery of the carrier 41 and meshes with a sun gear 45 provided at the center of the lower surface plate 31. The sun gear 45 can be rotated independently of the upper surface plate 19 and the lower surface plate 31 by driving means (not shown).
[0037]
An internal gear 44 is disposed around the lower surface plate 31 with a certain gap from the outer periphery of the lower surface plate 31, and meshes with the planet gear 43 of the carrier 41. The internal gear 44 has an inner peripheral surface concentric with the sun gear 45, and a gear portion is provided on the inner peripheral surface. The internal gear 44 can be rotated independently of the upper surface plate 19 and the lower surface plate 31 by driving means (not shown).
[0038]
On the other hand, as shown in FIG. 3 (b), one of the seven loading holes 42 provided in the carrier 41 is provided at the center of the carrier 41, and the remaining six surround the periphery thereof. They are provided radially at intervals of 60 °.
[0039]
As shown in FIGS. 3 and 4, the carrier 41 has an abrasive hole 46 in the vicinity of the outer periphery of the loading hole 42 that accommodates the wafer 30. The abrasive grain removal holes 46 are formed in six places so as to surround the outer periphery in an arc shape with respect to the loading hole 42. In addition, if it is a position which can extract the abrasive grain 35 excessively wound in the area | region 47 pinched | interposed into the wafer 30, the upper surface plate 19, and the carrier 41 shown in FIG. The position of may be any position.
[0040]
In the present embodiment, six abrasive hole 46 having a width of 5 mm are formed at a position of 2 mm close to the outer periphery of the loading hole 42. Although the position of the abrasive grain removal hole 46 is not particularly limited, it is as close as possible to the outer periphery of the loading hole 42 from the viewpoint of allowing the abrasive grains 35 caught in the region 47 shown in FIG. It is desirable to drill. However, considering the ease of processing, it is preferable to drill in the range of 2 mm to 10 mm close to the outer periphery of the loading hole 42. The width of the abrasive grain removal hole 46 is not particularly limited, but is preferably 5 mm to 8 mm in order to allow sufficient abrasive grains 35 to escape to the lower surface plate side.
[0041]
Each abrasive grain hole 46 has a central angle of 45 ° with respect to the center of the loading hole 42, and the interval between each abrasive grain hole 46 has a central angle of 10 °. In the present embodiment, from the viewpoint of maintaining the strength of the carrier 41, only six abrasive hole 46 are provided at the above position, but the number of abrasive hole 46 is not particularly limited.
[0042]
In addition, since the abrasive grain hole 46 is not provided in the position close | similar to the carrier 41 outer periphery, the space | interval of the abrasive grain hole 46 in this position has a center angle of 40 degrees. The reason why the abrasive hole 46 is not provided at a position close to the outer periphery of the carrier 41 is that, in the vicinity of the outer periphery of the carrier 41, the abrasive grains excessively wound in the region 47 sandwiched between the wafer 30, the upper surface plate 19 and the carrier 41. No. 35 is because the necessity of providing the abrasive grain removal hole 46 is thin because it easily escapes from the outer periphery of the carrier 41 by centrifugal force. However, the amount of the abrasive grains 35 present in the region 47 can be further optimized by providing the abrasive grain removal hole 46 at this position as necessary.
[0043]
In the present embodiment, the shape of the abrasive grain hole 46 is an arc shape, but the shape of the abrasive grain hole 46 is not limited to this, and may be circular, rectangular, or other polygonal shape. . Further, the hole need not be a hole as long as it has an effect similar to the effect of the abrasive grain removal hole 46 for removing the abrasive grains 35 excessively wound in the region 47.
[0044]
That is, as shown in Modification 1 in FIG. 5A, a circular concave portion 41 a or convex portion 41 b may be provided on the surface of the carrier 41 so as to surround the periphery of the loading hole 42. As a result, as shown in FIG. 5B, a relief 46a of the abrasive grains 35 is formed between the upper surface plate 19 around the wafer 30 and the carrier 41, and excess abrasive grains 35 are removed from the relief 46a. Can do. Therefore, an effect similar to that of the abrasive grain removal hole 46 can be achieved. Note that the concave portion 41a and the convex portion 41b may have a shape other than a circle.
[0045]
Further, as shown in Modification 2 in FIG. 6A, the periphery of the loading hole 42 of the carrier 41 may be deformed so as to be waved up and down, and the recess 41 c may be provided in the carrier 41. As a result, as shown in FIG. 6B, the relief grains 46 b of the abrasive grains 35 can be formed between the upper surface plate 19 and the carrier 41 around the wafer 30. be able to.
[0046]
Next, a method for wrapping the wafer 30 with the lapping machine 1 having the above-described configuration will be described below.
[0047]
When at least one of the sun gear 45 and the internal gear 44 shown in FIG. 3A is rotated by a rotation mechanism (not shown), the carrier 41 is rotationally driven by both gears. The carrier 41 performs planetary gear movement around the sun gear 45, and rotates and revolves. The direction and rotation speed of rotation and revolution of the carrier 41 are determined by the ratio of the rotation speeds of the sun gear 45 and the internal gear 44. Further, since the loading hole 42 provided in the carrier 41 is larger than the diameter of the wafer 30, the wafer 30 freely rotates in the loading hole 42 according to the movement of the carrier 41.
[0048]
On the other hand, the upper surface plate 19 and the lower surface plate 31 are driven so as to rotate in opposite directions by driving means (not shown). By these operations, the wafer 30 and the upper surface plate 19 and the lower surface plate 31 slide relative to each other, and a slurry in which abrasive grains 35 are mixed is supplied between the upper surface plate 19 and the lower surface plate 31. Polish the surface. The abrasive grains 35 are supplied from an abrasive supply tank (not shown) through a slurry supply hole 33 provided in the upper surface plate 19 shown in FIG.
[0049]
As shown in FIG. 4, the abrasive grains 35 contained in the slurry supplied from the slurry supply hole 33 flow into the gap between the upper and lower surface plates 19, 31, the wafer 30 and the carrier 41, and the lapping groove 34. The abrasive grains 35 supplied between the upper and lower surface plates 19 and 31 are supplied to the surface of the wafer 30 via the lapping grooves 34.
[0050]
Since the abrasive grains 35 are supplied through a slurry supply hole 33 provided in the upper surface plate 19, a large number of abrasive grains 35 are supplied particularly to a region 47 sandwiched between the wafer 30, the upper surface plate 19 and the carrier 41. Is done. However, since the carrier 41 is provided with the abrasive grain removal hole 46, the excessive abrasive grains 35 in the region 47 flow from the abrasive grain removal hole 46 to the lower surface plate side.
[0051]
As a result, only an appropriate amount of abrasive grains 35 exists in the region 47, and excessive polishing of the wafer on the outer peripheral surface 30a of the wafer can be prevented.
[0052]
Moreover, since the abrasive grains 35 that have flowed to the lower surface plate flow into the lapping grooves 34 when the required amount is exceeded, only an appropriate amount of abrasive grains 35 is supplied to the lower surface of the wafer.
[0053]
The used abrasive grains 35 and the grinding waste of the wafer 30 are discharged from the lapping surfaces 19a and 31a via the lapping grooves 34.
[0054]
By this polishing, the upper and lower surfaces of the wafer 30 are each polished by about 35 μm, and the wafer 30 having a thickness of 850 μm has a thickness of 780 μm. Note that the thickness (780 μm) of the polished wafer 30 is thicker than the thickness of the carrier 41 (750 μm).
[0055]
In this manner, lapping can be performed while maintaining the abrasive grains 35 held on the wafer surface, particularly the wafer outer peripheral surface 30a, in a suitable state. As a result, the flatness of the wrapped wafer can be improved.
[0056]
In the above embodiment, as shown in FIG. 3B, the carrier 41 is provided with seven loading holes 42 for accommodating the wafer 30, but it is possible to provide more than that. Hereinafter, for example, only one loading hole may be provided. In the above embodiment, the loading hole 42 has a circular shape larger than the diameter of the wafer 30. However, the loading hole 42 may be the same as the diameter of the wafer 30. In this case, the wafer 30 is forcibly rotated together with the carrier 41 while being fixed to the loading hole 42 without rotating in the loading hole 42 of the carrier 41. In addition, the loading hole 42 is not limited to a circular shape, and may have another shape such as an elliptical shape.
[0057]
Further, in the above-described lapping machine 1, the example in which the upper surface plate 19 and the lower surface plate 31 rotate in the reverse direction has been described. However, the upper surface plate 19 and the lower surface plate 31 may be rotated in the same direction. 19 and 31 may rotate only the carrier 41 without rotating.
[0058]
The material and size of the wafer are not limited at the time of carrying out the present invention, and semiconductor wafers such as silicon, GaAs, GaP, InP, etc., which are currently manufactured, can be manufactured in the future. The present invention can be applied to a very large wafer.
[0059]
As described above, the present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention with respect to the structure of the lapping machine and the carrier driving method. is there.
[0060]
[Implementation data]
The effect of wrapping a wafer using a conventional lapping machine and the effect of wrapping a wafer using a lapping machine to which the present invention is applied will be specifically described below.
[0061]
Multiple squares of a predetermined size are sampled from the lapped wafer, and the distance from the highest point to the lowest point on the wafer surface is calculated for each sample with reference to the wafer back surface, and the wafer flatness (TTV: Total Thickness Variation) Asked.
[0062]
As a result, the flatness TTV of the wafer lapped using a conventional lapping machine was 0.87 μm. On the other hand, the flatness TTV of the wafer lapped using the lapping machine to which the present invention was applied was 0.65 μm. From the result of the flatness (TTV) of the wafer, an improvement in flatness of 0.22 μm, that is, about 25% was observed as compared with the case of using a conventional lapping machine.
[0063]
Next, technical ideas other than the claims that can be grasped from the embodiment of the present invention will be described together with the effects thereof.
[0064]
An upper surface plate and a lower surface plate disposed so as to face each other in parallel, and a carrier that is disposed between the upper surface plate and the lower surface plate and has a loading hole that holds a workpiece. In the lapping machine in which a slurry containing abrasive grains is supplied to a workpiece, the lapping machine is provided with a relief for allowing the abrasive grains to escape on an upper surface of the carrier.
Thus, by providing the upper surface of the carrier with a relief for allowing abrasive grains to escape, excessive polishing of the upper surface of the wafer outer peripheral portion due to abrasive grains excessively present on the upper surface of the wafer outer peripheral portion can be prevented.
[0065]
An upper surface plate and a lower surface plate disposed so as to face each other in parallel, and a carrier that is disposed between the upper surface plate and the lower surface plate and has a loading hole that holds a workpiece. In the lapping machine in which a slurry containing abrasive grains is supplied to a workpiece, the carrier is provided with an abrasive grain punching hole penetrating from the upper surface to the lower surface only in the vicinity of the loading hole. .
In this way, by providing the abrasive punch hole penetrating from the upper surface to the lower surface of the carrier only in the vicinity of the loading hole, only the abrasive grains excessively present on the upper surface of the outer periphery of the wafer are extracted to the lower surface plate side, and the upper surface of the outer periphery of the wafer The flatness of can be improved.
[0066]
An upper surface plate and a lower surface plate disposed so as to face each other in parallel, and a carrier that is disposed between the upper surface plate and the lower surface plate and has a loading hole that holds a workpiece. In a lapping machine in which a slurry containing abrasive grains is supplied to a workpiece, the carrier is provided with a plurality of abrasive grain removal holes penetrating from the upper surface to the lower surface of the carrier in the vicinity of the loading hole. The lapping machine is characterized in that the gap between the hole and the abrasive punching hole is wider in the portion near the outer periphery of the carrier than in the other portions.
In this manner, even if the abrasive grain removal hole is omitted in the portion near the outer periphery of the carrier, excess abrasive grains existing in the vicinity of the carrier outer periphery easily escape from the carrier outer periphery by centrifugal force. Therefore, the space required for the abrasive grain removal hole can be reduced without substantially reducing the effect of removing excess abrasive grains. As a result, it is possible to drill the abrasive grains without increasing the size of the carrier, and the present invention can be applied to the conventional carrier relatively easily.
[0067]
【The invention's effect】
According to the lapping machine of the present invention, the amount of abrasive grains supplied to the machining point at the time of lapping is optimized using the shape of the abrasive punch hole, and the abrasive grains that are excessively wound at the machining point are moved to the lower surface plate side. This makes it possible to improve the flatness of the wrapped wafer.
[0068]
In addition, according to the lapping machine of the present invention, it is possible to improve the flatness of the upper peripheral portion of the wafer.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a schematic structure of a lapping machine according to the present invention.
FIG. 2 (a) is a bottom view of the upper surface plate, and FIG. 2 (b) is a plan view of the lower surface plate.
FIG. 3 (a) is a plan view showing a carrier rotation mechanism of a lapping machine according to the present invention, and FIG. 3 (b) is a plan view of the carrier.
FIG. 4 is an enlarged vertical sectional view of a main part of a lapping machine according to the present invention.
FIG. 5A is an enlarged perspective view of a main part showing a first modification of the carrier according to the present invention, and FIG. 5B is an enlarged vertical sectional view of the main part.
6 (a) is an enlarged perspective view of a main part showing a second modified example of the carrier according to the present invention, and FIG. 6 (b) is an enlarged vertical sectional view of the main part.
FIG. 7 is a longitudinal sectional view showing a schematic structure of a conventional general lapping machine.
FIG. 8 is an enlarged vertical sectional view of a main part of a prior art lapping machine.
[Explanation of symbols]
1 ... Lapping machine
11 ... Main cylinder 11a ... Rod
12 ... sub cylinder 12a ... rod
13 ... Lifting plate
15a ... Bolt 15b ... Washer 15c ... Through hole
19 ... Upper plate 19a ... Lapping surface
23 ... Bracket
30 ... Wafer 30a ... Wafer outer peripheral surface
31 ... Lower surface plate 31a ... Lapping surface
32 ... lower surface plate
33 ... Slurry supply hole
34 ... Lapping groove
35 ... abrasive
41 ... Carrier Concave part ... 41a Convex part ... 41b 41c ... Concave part
42 ... loading hole
43 ... Planet Gear
44. Internal gear
45 ... Sungear
46 ... Abrasive hole 46a ... Escape 46b ... Escape
47 ... area
50 ... Lapping machine
57 ... Upper surface plate
58 ... lower surface plate
60 ... Career.

Claims (4)

An upper surface plate and a lower surface plate arranged to face each other in parallel;
A carrier that is disposed between the upper surface plate and the lower surface plate and includes a loading hole for holding a workpiece;
In a lapping machine in which a slurry containing abrasive grains is supplied to the workpiece,
The carrier is provided with an abrasive hole penetrating from the upper surface to the lower surface of the carrier,
The lapping machine is characterized in that the abrasive hole is provided in the vicinity of the outer periphery of the loading hole and has an arc shape along the outer periphery of the loading hole so as to surround the outer periphery of the loading hole . 2. The lapping machine according to claim 1 , wherein the abrasive hole is provided in a range of 2 to 10 mm in proximity to an outer periphery of the loading hole. The lapping machine according to claim 1 or 2, wherein a width of the abrasive grain removal hole is 5 mm or more. The lapping hole according to any one of claims 1 to 3, wherein the abrasive hole is not provided near the outer periphery of the carrier.

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