JPH09168953A - Semiconductor wafer edge polishing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use the whole outer peripheral surface of a polishing plate for polishing by bringing the polishing plate into contact with the upper face side edge of a semiconductor wafer while rotating the polishing plate normally, and bringing the polishing plate into contact with the lower face side edge of the semiconductor wafer while rotating the polishing plate reversely to polish the upper face side edge and lower face side edge. SOLUTION: A polishing plate 12 is brought into contact with the upper face side edge of a semiconductor wafer while being rotated normally to polish the upper face side edge. The polishing plate 12 is further brought into contact with the outer peripheral end face of the semiconductor wafer while being rotated normally and reversely around a shaft 16 as the rotational center to polish the outer peripheral end face. The polishing plate 12 is then brought into contact with the lower face side edge of the semiconductor wafer while being rotated reversely to polish the lower face side edge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for edge polishing of a semiconductor wafer, and more particularly, to prevent overpolishing of a semiconductor wafer during edge polishing, and to eliminate mirror polishing residue to evenly polish the entire surface of the edge uniformly. However, it is possible to improve the yield of semiconductor chips by increasing the area of a semiconductor wafer that can be effectively used, and by preventing the generation of dust due to the lack of the edge to significantly reduce the influence of dust during electronic component manufacturing. The present invention relates to an edge polishing method and apparatus for a semiconductor wafer, which is suitable for manufacturing a high-capacity memory device such as a 256-megabit DRAM having a fine pattern width.

[0002]

2. Description of the Related Art In FIGS. 16 and 17, a semiconductor wafer 1 is a general term for a thin disk-shaped semiconductor, and is usually cut into a disk shape from a columnar refined single crystal base material.
The flatness of the one surface 1a is mirror-polished to 1 μm or less,
Various semiconductor elements are formed on the surface by an etching method or the like.

The semiconductor wafer 1 has, for example, a size of 10 mmφ to 400 mmφ and a thickness of 200 μm.
It is a thin disk shape of 10 mm to 10 mm, and in order to easily match the azimuth in the circumferential direction, a part of the outer peripheral portion 1b is ground linearly to form a so-called orientation flat 1
c is being formed.

However, orientation flat 1c
Is formed by cutting a part of the semiconductor wafer 1 in a straight line, so that as the size of the semiconductor wafer 1 increases in recent years, the number of cut parts also increases and waste that cannot be ignored occurs. There was a problem in using it efficiently.

From these requirements, the outer peripheral portion 1b of the semiconductor wafer 1 is replaced with the orientation flat 1c.
A V-shaped notch portion 1d is formed on the semiconductor wafer 1 and a positioning pin (not shown) is brought into contact with the notch portion 1d to form the semiconductor wafer 1
The method of performing the positioning is performed.

On the other hand, a problem in performing fine processing on the surface of the semiconductor wafer 1 is dust generated from the surface 1a and the outer peripheral surface 1b of the semiconductor wafer 1, that is, the outer peripheral surface 1b and the outer peripheral surface 1b of the semiconductor wafer 1. Orientation flat 1
c. If the edge 1e of the notch portion 1d is sharp, when a positioning pin or the like is brought into contact with the edge 1e, chips or chips are generated, which causes dust.

[0007] Such dust not only adheres to the surface 1a of the semiconductor wafer 1 to reduce the yield of electronic components manufactured on the semiconductor wafer 1, but also deteriorates the performance of the manufactured electronic components. It was.

[0008] This problem tends to decrease the line width of the pattern as the degree of integration increases in recent years. For example, in a DRAM of 256 Mbytes, the line width of the pattern becomes 0.2 μm to 0.3 μm. Therefore, it is a serious problem in improving the yield and productivity.

Removing the outer peripheral surface 1b, the orientation flat 1c and the edge 1e of the notch 1d
This is an effective means for preventing the generation of dust, and for this purpose, in FIGS. 18 to 21, a rotary grindstone (not shown) is used.
The edge 1e has a surface roughness of 0.05 μm to 0.
After grinding to about 07 μm, the surface roughness of the edge 1e of the semiconductor wafer 1 is further increased from 0.01 μm to 0.01 μm.
It is necessary to finish the mirror surface to about 5 μm.

The conventional polishing of the edge 1e is made of cloth, urethane foam resin or the like while supplying the abrasive (slurry) 4 from the discharge nozzle 5 and slowly rotating the semiconductor wafer 1 in the direction of arrow A. The V-shaped groove 2b formed on the outer peripheral portion 2a of the first polishing plate 2 is brought into contact with the edge 1e of the semiconductor wafer 1 with a load of 1 kg to 5 kg, and is rotated in the direction of arrow B so that the upper and lower edges 1e are removed. After polishing, the second polishing plate 3 was rotated in the direction of arrow C to bring the flat outer peripheral surface 3a into contact with the outer peripheral portion 1b of the semiconductor wafer 1 to polish the outer peripheral portion 1b.

However, according to the conventional polishing, as shown in FIGS. 20 and 21, the shape of the V-shaped groove 2b is deformed or the V-shaped groove 2b becomes deep and the original polishing is performed in FIG. 20 and FIG. There is a drawback in that an overpolish phenomenon occurs in which the surface 1a of the semiconductor wafer 1 that must not be polished is polished, and the surface area that can be effectively used is reduced.

Further, an edge 1e polished by the first polishing plate 2 and an outer peripheral portion 1b polished by the second polishing plate 3
It was difficult to polish the boundary portion 1f with and the boundary portion 1f remained without being sufficiently polished, and this was a cause of dust generation.

Further, if the diameter or notch of the semiconductor wafer is processed to an accurate dimension, the positioning time at the time of fine processing in the next process can be shortened, so that highly accurate grinding is required. It

[0014]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art. The purpose of the present invention is to rotate the polishing plate in the forward direction while the upper surface side edge of the semiconductor wafer is being rotated. To the lower surface side edge of the semiconductor wafer while rotating the polishing plate in the reverse direction and up-cut to polish the upper surface side edge and the lower surface side edge, and further move the polishing plate in the forward and reverse directions. While alternately rotating, the outer peripheral edge surface of the semiconductor wafer is brought into contact with the outer peripheral edge surface to polish the outer peripheral edge surface so that the entire outer peripheral surface of the polishing plate can be used for polishing. The purpose is to prevent abrasion, reduce the frequency of exchanging the polishing plate, and enable stable polishing for a long time.

Another object of the present invention is that, with the above-described structure, the direction in which overpolishing occurs is the outer peripheral direction of the semiconductor wafer, and the boundary portion, which was difficult to polish in the past, can also be mirror-polished by utilizing this overpolishing phenomenon. This also makes it possible to carry out uniform mirror polishing over the entire surface, and when a positioning pin or the like is brought into contact with the edge, the generation of chips or chips is prevented, and By making it possible to prevent a decrease in yield and performance deterioration of electronic parts, and by making it possible to manufacture a pattern with a finer line width, it is possible to manufacture an electronic part of ultra-high capacity. is there.

Still another object is to rotate the polishing plate around an axis in the direction perpendicular to the thickness direction of the semiconductor wafer as a rotation center, and bring the polishing plate into contact with the semiconductor wafer while reciprocating in the axial direction of the axis. By polishing the edge of the semiconductor wafer by means of polishing, the influence of the surface roughness of the polishing plate can be minimized and the edge can be uniformly mirror-polished.

Still another object is to bring the first polishing plate, which has an obtuse angle whose cross-sectional shape is substantially larger than a right angle, into contact with the upper edge of the V-shaped notch while rotating the first polishing plate in the normal direction. While rotating the first polishing plate in the reverse direction, the first polishing plate is brought into contact with the lower surface side edge of the V-shaped notch to polish the upper and lower surface side edges of the V-shaped notch by up-cut, and the cross-sectional shape of the outer peripheral portion of the polishing plate is close to a right angle. The V-shaped notch formed on the outer periphery of the semiconductor wafer is polished by contacting the end face of the V-shaped notch while rotating the second polishing plate formed on the V-shaped notch alternately in the forward and reverse directions. The whole surface of the edge of the letter notch can be mirror-polished uniformly without overpolishing.

Still another object is, with respect to a semiconductor wafer held horizontally on a turntable, a Z direction which is a thickness direction of the semiconductor wafer, an X direction in a horizontal plane orthogonal to the Z direction, and the X direction. A polishing plate shaft that is rotatable in forward or reverse directions is provided in a 3-axis moving mechanism that is movable in three Y directions orthogonal to the polishing plate, and the polishing plate is fixed to the polishing plate shaft. By contacting the upper and lower surface side edges and the outer peripheral end surface of the semiconductor wafer while moving in three directions,
The purpose is to enable automatic and efficient polishing of the edge of a semiconductor wafer by means of an edge polishing device of a table.

Another object is a polishing plate which is rotatable in a forward or reverse direction by a three-axis moving mechanism which is movable in three directions of X and Y directions in the horizontal plane and Z direction orthogonal to the horizontal plane. A first polishing plate having a shaft and an outer peripheral portion of the polishing plate having an obtuse angle which is considerably larger than a right angle and a second polishing plate having an outer peripheral portion having an angle of a right angle. By arranging at least a pair of polishing plates composed of and fixedly, the first polishing plate polishes the edge of the outer peripheral portion of the semiconductor wafer as described above while moving the polishing plates in three directions. Polish the top and bottom edges of the V-shaped notch with an abrasive plate by up-cutting,
By rotating the second polishing plate alternately in the forward and reverse directions to polish the end face of the V-shaped notch, the outer peripheral portion of the semiconductor wafer and the edge of the V-shaped notch are automatically polished by one edge polishing apparatus. It is to be able to do it.

Still another object is that the first polishing plate formed on the polishing plate shaft disposed in the three-axis moving mechanism has an obtuse angle whose cross-sectional shape is significantly larger than the right angle, and the cross-sectional shape of the outer peripheral part is at a right angle. By constructing a unit by fixing a pair of polishing plates with a second polishing plate formed at a close angle, the unit can be easily replaced when the polishing plate is replaced. In addition, the rest period of the edge polishing apparatus is shortened by this, and the polishing operation of the semiconductor wafer can be efficiently performed.

[0021]

SUMMARY OF THE INVENTION In summary, the method of the present invention (claim 1) is an edge polishing method for a semiconductor wafer, wherein a rotating polishing plate is brought into contact with an outer peripheral edge of the semiconductor wafer to polish the edge. To the upper surface side edge of the semiconductor wafer while positively rotating the polishing plate around the axis of the direction perpendicular to the thickness direction of the semiconductor wafer as the center of rotation so as to polish by upcut from the outer peripheral direction of the semiconductor wafer toward the center direction. A first step of contacting and abrading the upper surface side edge; and abutting the outer peripheral end surface of the semiconductor wafer by abutting the outer peripheral end surface of the semiconductor wafer while rotating the polishing plate in the forward and reverse directions about the shaft as a rotation center. Second step of polishing and polishing the polishing plate by up-cut from the outer peripheral direction of the semiconductor wafer toward the center direction with the shaft as the center of rotation. It is characterized in that grinding the edge of the semiconductor wafer while reverse rotation to so that it abuts the allowed the lower surface side edge of the semiconductor wafer by a third step of grinding the lower surface side edge.

Further, in the method of the present invention (claim 2), the edge of the semiconductor wafer is polished by bringing a polishing plate rotating around an axis perpendicular to the thickness direction of the semiconductor wafer as a rotation center into contact with the edge. In the method of edge polishing a semiconductor wafer, the polishing plate is brought into contact with the upper surface side edge of the semiconductor wafer while being positively rotated so as to polish by up-cut from the outer peripheral direction of the semiconductor wafer toward the center direction thereof. A first step of polishing the side edge, and a second step of abutting the outer peripheral end surface of the semiconductor wafer while polishing the outer peripheral end surface while rotating the polishing plate in the forward and reverse directions about the axis as a rotation center. , The polishing plate is rotated in the opposite direction from the outer peripheral direction of the semiconductor wafer toward the center of the semiconductor wafer by the up-cut with the shaft as the center of rotation. The third step of abutting the lower surface side edge of the semiconductor wafer and polishing the lower surface side edge is to polish the edge of the semiconductor wafer, and at the time of polishing in each step, the polishing plate is attached to the axis of the shaft. The polishing plate is brought into contact with the semiconductor wafer while reciprocating in the direction to polish the edge of the semiconductor wafer.

Further, in the method of the present invention (claim 3), a polishing plate which rotates about an axis perpendicular to the thickness direction of the semiconductor wafer as a rotation center is applied to the edge of the V-shaped notch formed on the outer periphery of the semiconductor wafer. In the method for edge polishing a semiconductor wafer in which the edges are brought into contact with each other to polish the edge, a first polishing plate having an obtuse angle whose cross-sectional shape of an outer peripheral portion of the polishing plate is considerably larger than a right angle is provided from the outer peripheral direction of the semiconductor wafer toward the center. A first step of polishing the upper surface side edge of the V-shaped notch by abutting the upper surface side edge of the V-shaped notch while rotating forward so as to polish by upcut; and a cross section of the outer peripheral portion of the polishing plate. The second polishing plate having a shape close to a right angle is brought into contact with the end face of the V-shaped notch while rotating in the forward and reverse directions about the shaft as a rotation center. A second step of polishing the end face of the V-shaped notch, and the V-shape while rotating the shaft in the reverse direction so as to polish the first polishing plate from the outer peripheral direction of the semiconductor wafer toward the center by upcut. The third step of polishing the lower surface side edge of the V-shaped notch by contacting the lower surface side edge of the notch, and polishing the edge of the V-shaped notch of the semiconductor wafer.

The apparatus of the present invention (claim 4) comprises a turntable for rotating a semiconductor wafer while holding it horizontally, and a movable table having a shaft center perpendicular to and offset from the rotation axis of the turntable. A polishing plate fixed to a polishing plate shaft rotatably disposed, and a drive device for rotating the polishing plate together with the polishing plate shaft in a forward direction or a reverse direction,
A three-axis moving mechanism configured to move the movable table in three directions: a Z direction which is a thickness direction of the semiconductor wafer, an X direction in a horizontal plane orthogonal to the Z direction, and a Y direction orthogonal to the X direction. The semiconductor wafer is abutted against the upper surface side edge of the semiconductor wafer while rotating the polishing plate forward so as to polish by up-cut from the outer peripheral direction toward the center direction of the semiconductor wafer, and the upper surface side edge is ground, While rotating the polishing plate alternately in the forward and reverse directions, the polishing plate is brought into contact with the outer peripheral end face of the semiconductor wafer to polish the outer peripheral end face, and further the polishing plate is directed from the outer peripheral direction of the semiconductor wafer toward the center direction. It is configured such that the lower surface side edge of the semiconductor wafer is brought into contact with the lower surface side edge of the semiconductor wafer while being rotated in the reverse direction so that the lower surface side edge is polished. A.

The device of the present invention (Claim 5) comprises a turntable for rotating a semiconductor wafer while holding it horizontally, and a movable table having a shaft center perpendicular to and offset from the rotation axis of the turntable. A first polishing plate fixed to a rotatably arranged polishing plate shaft and having an obtuse angle whose cross-sectional shape at the outer peripheral portion is considerably larger than a right angle, and a second polishing plate which is formed at an angle close to a right angle at the outer peripheral portion At least a pair of polishing plates comprising polishing plates; a drive device for rotating the polishing plates together with the polishing plate axis in the forward direction or the reverse direction; and the movable table in the Z direction, which is the thickness direction of the semiconductor wafer, Z
A three-axis moving mechanism configured to be movable in three directions of an X direction in a horizontal plane orthogonal to the direction and a Y direction orthogonal to the X direction, and the first polishing plate from the outer peripheral direction to the center direction of the semiconductor wafer. To the upper edge of the V-shaped notch while rotating forward so that the upper edge of the V-shaped notch is abraded, and the second polishing plate is rotated in the forward and reverse directions. While rotating alternately, the end face of the V-shaped notch is brought into contact with the end face of the V-shaped notch and the end face of the V-shaped notch is polished, and the first polishing plate is further polished from the outer peripheral direction toward the center direction by upcut. While rotating in reverse, the lower edge of the V-shaped notch is brought into contact with the lower edge of the V-shaped notch to polish the lower edge of the V-shaped notch. It is characterized in that it has configured to milling.

The device of the present invention (claim 6) is a polishing plate for abutting against the edge of the semiconductor wafer and polishing the edge while rotating in the thickness direction of the semiconductor wafer,
A pair of first polishing plates whose outer peripheral section has an obtuse angle which is considerably larger than a right angle, and a second polishing plate whose outer peripheral section has an almost right angle and which are fixed to the polishing plate shaft. It is characterized by.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION A semiconductor wafer 15 according to the present invention will be described below.
Taking the case of polishing the V-shaped notch 15c of FIG. 1 to 4, a semiconductor wafer edge polishing apparatus 10 according to the present invention.
Is a turntable 11, a polishing plate 12, and a drive unit 1.
3 and a triaxial moving mechanism 14.

The turntable 11 is a semiconductor wafer 1
5 for attaching and processing 5, and the upper surface 11
An air suction hole 11b and an air suction groove 11c are formed in a, and the air suction hole 11b and the air suction groove 11c are
A vacuum pump (not shown) is communicatively connected, and air acts on the air suction hole 11b and the air suction groove 1 by the action of the vacuum pump.
The semiconductor wafer 15 is sucked from 1c and fixed to the upper surface 11a.

The turntable 11 is provided with a centering mechanism (not shown) for aligning the rotation center of the semiconductor wafer 15 with the rotation center of the turntable 11.

Further, the turntable 11 is rotatably supported by a base (not shown) and is directly connected to a rotary shaft of a DC servo motor (not shown) so as to rotate the DC servo motor. Thus, the turntable 11 is configured to rotate together with the semiconductor wafer 15.

The polishing plate 12 is for polishing the edge 15b of the semiconductor wafer 15 in FIGS. 3 and 4, and is a disk made of a material such as urethane foam resin or artificial leather having a diameter of about 160 mm. And the outer periphery 1
The first polishing plate 1 has a sectional shape of 2a, that is, an obtuse angle whose top surface angle θ is considerably larger than a right angle, for example, θ = 148 °.
2A and a second polishing plate 12B having a cross-sectional shape of the outer peripheral portion 12a, that is, a second polishing plate 12B formed so that the angle θ of the top surface is close to a right angle, for example, θ = 92 °, are fixed to the polishing plate shaft 16. The polishing plate device 19 is configured by being fixed by the nuts 18 at intervals of.

The polishing plate 12 is composed of two types of polishing plates 12, a first polishing plate 12A and a second polishing plate 12B, because the V-shaped notch formed in the semiconductor wafer 15 as a notch having an opening angle of 90 °. When polishing 15c, polishing plate 1
When the 2 is brought into contact with the V-shaped notch 15c from above or below, the first polishing formed at an angle of 148 ° so as to come into contact with the entire upper surface side edge 15d or the lower surface side edge 15e of the V-shaped notch 15c. The plate 12A allows the upper edge 15d and the lower edge 15e of the V-shaped notch 15c.
Is ground and adjusted according to the opening angle of the V-shaped notch 15c.
This is so that the end portion 15f of the V-shaped notch 15c can be polished by the second polishing plate 12B formed at an angle of °.

In FIG. 1, two types of polishing plates 12 (first
The polishing plate shaft 16 to which the polishing plate 12A and the second polishing plate 12B) are fixed has an axis perpendicular to the axis of the turntable 11 and at a radius distance of the semiconductor wafer 15 from the axis.
The movable base 20 is rotatably arranged by being offset by a distance obtained by adding the two radial distances.

A pulley 21 is fixed to one end of the polishing plate shaft 16, and is connected to a pulley 22 fixed to a rotating shaft of a reversible motor 13 which is a drive unit fixed to a movable table 20 and which can be rotated in the forward and reverse directions. A belt 23 is wrapped around the polishing plate shaft 16, that is, by rotating the reversible motor 13, the polishing plate shaft 16, that is, the polishing plate 12 is rotated in the forward direction (arrow D direction) or the reverse direction (arrow E direction). .

In the triaxial moving mechanism 14, the polishing plate shaft 16 to which the polishing plate 12 is fixed is moved in the Z direction, which is the thickness direction of the semiconductor wafer 15, the X direction in the horizontal plane orthogonal to the Z direction, and the X direction. In order to move in three directions of the Y direction orthogonal to each other, in FIGS. 1 and 2, the X moving base 22 is similar to the Y moving base 24 and the movable base 20 described later with respect to the base not shown. The mechanism is configured to be movable in the X direction, and the X moving table 22 is moved in the arrow F or G direction to move the polishing plate 12 away from or toward the semiconductor wafer 15 attracted to the turntable 11. It is designed to be moved to.

The guide blocks 24a of the Y moving table 24 are attached to the two guide rails 22a provided on the X moving table 22.
Is slidably fitted to the X-movement base 22, and two bearings 25 and a reversible motor 26, each of which has a ball screw 28 rotatably disposed therein, are disposed on the X-moving base 22, and are fixed to one end of the ball screw 28. The belt 31 is wound around the pulley 29 and the pulley 30 fixed to the rotation shaft of the reversible motor 26, and the reversible motor 26 is rotated to rotate the ball screw 28 in the forward and reverse directions. ing.

A nut 37 fixed to the Y moving table 24 is screwed onto the ball screw 28, and the rotation of the ball screw 28 is converted into a horizontal movement in the Y direction by the nut 37 so that the Y moving table 24 is moved.
Is guided by the guide rail 22a to move in the Y direction (the axial direction of the polishing plate shaft 16).

A column 24b having a guide rail 24a arranged vertically is fixed to the Y moving table 24, and a ball screw 32 having a pulley 33 fixed to one end is vertically rotatable on the column 24b. A belt 38 is wound around a pulley 36 fixed to a rotary shaft 35 of a reversible motor 34 fixed above the Y moving table 24.

A guide block 20a provided on the movable table 20 is slidably fitted to the guide rail 24a, and a nut (not shown) fixed to the movable table 20 is screwed on the ball screw 32. The rotation of the ball screw 32 is converted into vertical movement in the Z direction by the nut so that the movable table 20 is guided by the guide rail 24a and moved in the Z direction.

The method of the present invention (claim 1) is an edge polishing method for a semiconductor wafer in which the rotating polishing plate 12 is brought into contact with the edge 15b of the outer periphery 15a of the semiconductor wafer 15 to polish the edge 15b. Is rotated forward about the axis 16 of the direction perpendicular to the thickness direction of the semiconductor wafer 15 as the center of rotation from the outer peripheral direction of the semiconductor wafer 15 toward the center direction so as to be polished by up-cutting to the edge 15b on the upper surface side of the semiconductor wafer 15. The first step of abutting and abrading the upper surface side edge 15b, and the abrading plate 12 abutting against the outer peripheral end surface 15a of the semiconductor wafer 15 while rotating the polishing plate 12 in the forward and reverse directions about the shaft 16 as a rotation center, The second step of polishing the end surface 15a, and the polishing plate 12 from the outer peripheral direction of the semiconductor wafer 15 to the center direction with the shaft 16 as the center of rotation. Edge 1 of the semiconductor wafer 15 by a third step while reverse rotation to polished by up-cut is brought into contact with the lower surface side edge 15b of the semiconductor wafer 15 is polished to lower side edge 15b toward the
5b is a method of polishing.

Further, according to the method of the present invention (claim 2), the polishing plate 12 rotating about the axis 16 in the direction perpendicular to the thickness direction of the semiconductor wafer 15 as the center of rotation is brought into contact with the edge 15b of the outer periphery 15a of the semiconductor wafer 15. In the edge polishing method for polishing the semiconductor wafer 15 by polishing the edge 15b with the upper edge of the semiconductor wafer 15, the polishing plate 12 is rotated in the forward direction from the outer peripheral direction of the semiconductor wafer 15 toward the center so as to polish by upcut, and the upper edge 15b of the semiconductor wafer 15 is polished. A first step of polishing the upper surface side edge 15b of the semiconductor wafer 15 and contacting the outer peripheral end surface 15a of the semiconductor wafer 15 while rotating the polishing plate 12 in the forward and reverse directions about the axis 16 as a rotation center. The second step of polishing the outer peripheral end surface 15a, and the polishing plate 12 is centered from the outer peripheral direction of the semiconductor wafer 15 with the shaft 16 as the center of rotation. The edge 15b of the semiconductor wafer 15 is polished by the third step of abutting against the lower surface side edge 15b of the semiconductor wafer 15 and polishing the lower surface side edge 15b while rotating in the opposite direction so as to polish by upcut Together with the polishing plate 12 during polishing in each process
Is a method of polishing the edge 15b of the semiconductor wafer 15 by bringing the polishing plate 12 into contact with the semiconductor wafer 15 while reciprocating in the axial direction of the shaft 16.

In the method of the present invention (claim 3), the V-shaped notch 15 formed on the outer periphery 15a of the semiconductor wafer 15 is used.
c edge 15d. In the edge polishing method for a semiconductor wafer 15 in which a polishing plate 12 rotating about an axis 16 perpendicular to the thickness direction of the semiconductor wafer 15 is brought into contact with 15e to polish edges 15d and 15e, the polishing plate 1
The V-shaped notch while rotating the first polishing plate 12A in which the cross-sectional shape of the outer peripheral portion 12a of 2 is an obtuse angle that is considerably larger than a right angle so as to polish by upcut from the outer peripheral direction of the semiconductor wafer 15 toward the center direction. The first step of abutting against the upper edge 15d of the V-shaped notch 15c to polish the upper edge 15d of the V-shaped notch 15c, and the second polishing in which the cross-sectional shape of the outer peripheral portion 12a of the polishing plate 12 is formed at an angle close to a right angle. The end face 15f of the V-shaped notch 15c is rotated while the plate 12B is rotated about the axis 16 in the forward and reverse directions.
A second step of polishing the end face 15f of the V-shaped notch 15c by abutting the first polishing plate 12A on the semiconductor wafer 15
While rotating the shaft 16 in the reverse direction about the center of rotation so as to grind by up-cutting from the outer peripheral direction toward the center, the lower surface side edge 15e of the V-shaped notch 15c is brought into contact with the lower surface side edge 15e of the V-shaped notch 15c. The V-shaped notch 1 of the semiconductor wafer 15 by the third step of polishing
This is a method of polishing the edges 15d and 15e of 5c.

The present invention is configured as described above,
Hereinafter, the operation will be described. In FIG. 13, in order to form a V-shaped notch 15c on a semiconductor wafer 15 by cutting a disk-shaped single crystal base material (not shown) refined into a cylindrical shape, the end face has a V-shaped cross section. Whetstone 3
While rotating 9 in the direction of arrow J, it is brought into contact with the outer peripheral portion 15a of the semiconductor wafer 15 for grinding, and the V-shaped notch 1
5c is processed (Figs. 13 (a), (b), (c),
(D), (e)).

At this time, the edge 1 of the semiconductor wafer 15
Since 5b remains at a right angle, first of all, as shown in FIG.
In (f), while slowly rotating the semiconductor wafer 15 in the arrow K direction, the grindstone 40 having the V-shaped groove 40a formed therein is rotated in the arrow L direction to abut against the edge 15b, and the end surface 41a is flat. While rotating the grindstone 41 formed in the direction of the arrow M in the direction of the arrow N, the edge 15b and the outer peripheral portion 15a of the semiconductor wafer 15 are chamfered and ground to have a surface roughness of 0.05 μm to 0.07 μm. To a degree.

Then, while the abrasive 43 is being supplied from the nozzle 44, the grindstone 42 having a V-shaped cross section is rotated in the direction of the arrow O to abut against the upper edge 15d of the V-shaped notch 15c to chamfer the upper edge 15d. Processing (Fig. 1
3 (g)), while rotating the grindstone 42 alternately in the directions of arrows O and P, the grindstone 42 is brought into contact with the end surface 15f of the V-shaped notch 15c to grind the end surface 15f (FIG. 13 (h)).
While being rotated in the direction of arrow P, the lower surface side edge 15e of the V-shaped notch 15c is brought into contact with the lower surface side edge 15e to chamfer the lower surface side edge 15e (FIG. 13 (i)), and the edge portion is chamfered. Roughness is 0.05μm to 0.07μ
A semiconductor wafer 15 having a size of about m is manufactured (FIG. 13).
(J)).

In the grinding process using the above-mentioned grindstones 39, 40, 41 and 42, the surface roughness of the ground surface of the semiconductor wafer 15 is about 0.05 μm to 0.07 μm, and the line width of the pattern is 0.2 μm to 0.2 μm. It is insufficient to manufacture an electronic device with a size of 0.3 μm,
Mirror finishing is required to a surface roughness of about 5 μm.

FIG. 1, FIG. 5 to FIG. 10, FIG. 14 and FIG.
, The center of rotation of the semiconductor wafer 15 and the center of rotation of the turntable 11 are aligned by the centering mechanism, and the air suction hole 11b and the air suction groove 1 of the turntable 11 are aligned.
After the air is sucked from 1c to adsorb the semiconductor wafer 15 and fix it to the upper surface 11a, the DC servomotor is rotated to attach the turntable 11 to the semiconductor wafer 15
Slowly rotate with.

X in FIGS. 5, 6 and 14B.
While moving the moving table 22 in the X direction, the reversible motor 2
6 to rotate the ball screw 28 to rotate the Y moving base 2
4 is moved in the Y direction while being guided by the guide rail 22a, and the first polishing plate 12A of the two types of polishing plates 12 fixed to the polishing plate shaft 16 is opposed to the V-shaped notch 15c of the semiconductor wafer 15. Position it.

The reversible motor 34 rotates the ball screw 32 to move the movable table 20 in the Z direction along the guide rail 24a, and the first polishing plate 12A is brought into contact with the upper edge 15d of the V-shaped notch 15c. , Reversible motor 13
Is transmitted to the first polishing plate 12A via the pulley 22, the belt 23, the pulley 21, and the polishing plate shaft 16 to rotate the first polishing plate 12A in the forward direction (arrow D direction), While supplying the polishing agent 46 from the nozzle 45, the upper surface side edge 15d is polished by up-cutting.

At this time, in FIG. 12, the first polishing plate 1
Since the cross section of the outer peripheral portion 12a of 2A is formed with an angle θ of 148 °, the outer peripheral portion 12a is in contact with the entire upper surface side edge 15d, and in FIG. 15 and FIG. By moving 22 in the X direction to move the polishing plate 12 in the arrow F direction and simultaneously rotating the reversible motor 34 to move the movable table 20 in the Z direction,
The first polishing plate 12A is moved along the upper surface side edge 15d in the direction of the arrow Q to uniformly polish the upper surface side edge 15d.

Further, the reversible motor 26 is rotated to rotate the ball screw 28 in the forward and reverse directions to move the Y moving table 24.
Together with the polishing plate shaft 16 in the direction of arrow H or I from 100 to 2
By reciprocating with a stroke of about 00 μm for polishing, the variation in surface roughness of the polishing plate 12 can be averaged and the semiconductor wafer 15 can be uniformly polished.

After the polishing of the upper surface side edge 15d is completed,
In FIGS. 7 and 8, the reversible motor 26 is rotated again to guide the Y moving table 24 to the guide rail 22a, and Y
The second polishing plate 12B of the two types of polishing plates 12 fixed to the polishing plate shaft 16 by moving the second polishing plate 12B to the semiconductor wafer 15
Of the V-shaped notch 15c, the reversible motor 34 rotates the ball screw 32 to move the movable table 20 downward along the guide rail 24a, and the second polishing plate 12B moves to the V-shaped notch 15c. Abut on the cross section 15f.

In FIG. 11, since the cross section of the outer peripheral portion 12a of the second polishing plate 12B is formed with an angle θ of 92 °, the outer peripheral portion 12a has a cross section 15f of the V-shaped notch 15c.
, The reversible motor 13 is alternately rotated in the forward direction (direction of arrow D) and the reverse direction (direction of arrow E), and the reversible motor 26 is rotated in the forward direction and reverse direction to move the Y moving table. The polishing plate shaft 16 together with 24, that is, the second polishing plate 1
The cross section 15f of the V-shaped notch 15c is evenly polished while reciprocating 2B in the direction of arrow H or I with a stroke of about 100 to 200 μm (FIG. 14 (d)).

Next, the reversible motor 26 is rotated to guide the Y moving table 24 by the guide rail 22a to move it in the Y direction, and the first polishing plate 12A is again moved to the semiconductor wafer 15
It is located so as to face the V-shaped notch 15c.

In FIGS. 9 and 10, the reversible motor 34 rotates the ball screw 32 to rotate the movable table 2
0 is moved downward along the guide rail 24a, and at the same time, the X moving table 22 is moved in the direction of arrow G to move the first polishing plate 12A along the lower surface side edge 15e.
The reversible motor 13 is rotated in the reverse direction (arrow E direction) and the reversible motor 26 is rotated in the forward direction and the reverse direction so that the polishing plate shaft 16, that is, the first polishing plate 12 together with the Y moving table 24 is rotated.
The lower surface side edge 15e of the V-shaped notch 15c is ground while reciprocating A in the direction of arrow H or I with a stroke of about 100 to 200 μm (FIGS. 14E and 14F).

As described above, the first polishing plate 12A and the second polishing plate 12A
100 to 2 by using a pair of polishing plates 12 of polishing plate 12B
When about 100 semiconductor wafers 15 are polished, the cross-sectional shape of the outer peripheral portion 12a of the polishing plate 12 is deformed and sufficient mirror surface processing becomes difficult. Therefore, the polishing plate 12 needs to be replaced. Since a pair of spare polishing plates 12 is attached to 16, the reversible motor 26 is rotated to rotate the Y moving table 2
The polishing plate 12 can be replaced easily and in a short time only by guiding 4 to the guide rail 22a to move it in the Y direction and moving the spare polishing plate 12 to a position facing the V-shaped notch 15c.

In the above-mentioned embodiment, the edge to be ground is described as the edge of the V-shaped notch, but the edge to be ground is not limited to the edge of the V-shaped notch, and the edge of the entire outer periphery of the semiconductor wafer can be used. It can be polished in the same manner. In the case of an edge of the outer periphery other than the V-shaped notch, the cross-sectional shape of the outer periphery of the polishing plate 12, that is, the angle θ of the top surface does not need to be sharpened to a right angle, but a flat surface (for example, the angle θ = 180 °).

[0058]

According to the present invention, the polishing plate is brought into contact with the upper surface side edge of the semiconductor wafer while rotating in the forward direction as described above.
While rotating the polishing plate in the reverse direction, the polishing plate is brought into contact with the lower surface side edge of the semiconductor wafer to polish the upper surface side edge and the lower surface side edge by up-cutting, and further the polishing plate is alternately rotated in the forward and reverse directions. Since the outer peripheral end surface of the semiconductor wafer is brought into contact with the outer peripheral end surface to be polished,
There is an effect that the entire outer peripheral surface of the polishing plate can be used for polishing, and as a result, uneven wear of the outer peripheral surface can be prevented, the frequency of replacement of the polishing plate can be reduced, and stable polishing can be performed for a long time. is there.

Further, with the above structure, the direction in which overpolishing occurs is the outer peripheral direction of the semiconductor wafer, and the boundary portion, which has been difficult to polish in the past, can be mirror-polished by utilizing the overpolishing phenomenon. Uniform mirror polishing can be performed, and when a positioning pin or the like is brought into contact with the edge, generation of chips or chips is prevented, and deterioration of the yield of electronic components and performance deterioration of electronic components due to the dust are prevented. There is an effect that it is possible to manufacture a pattern having a finer line width, and it is possible to manufacture an electronic component of ultra-high capacity.

Further, the polishing plate is rotated about the axis perpendicular to the thickness direction of the semiconductor wafer as the center of rotation, and
Since the polishing plate is brought into contact with the semiconductor wafer while reciprocating in the axial direction of the shaft so as to polish the edge of the semiconductor wafer, the edge is uniformly mirror-polished while minimizing the influence of the surface roughness of the polishing plate. The effect is that you can.

Further, the first polishing plate whose cross-sectional shape of the outer peripheral portion of the polishing plate has an obtuse angle which is considerably larger than a right angle is brought into contact with the upper surface side edge of the V-shaped notch while rotating forward, and the first polishing plate is also fixed. While rotating in the reverse direction, abutting against the lower surface side edge of the V-shaped notch, the upper and lower surface side edges of the V-shaped notch are polished by up-cutting, and the cross-sectional shape of the outer peripheral portion of the polishing plate is formed at an angle close to a right angle. 2 While rotating the polishing plate alternately in the forward and reverse directions, the polishing plate is brought into contact with the end face of the V-shaped notch to polish the end face of the V-shaped notch.
There is an effect that the entire surface of the edge of the V-shaped notch formed on the outer periphery of the semiconductor wafer can be mirror-polished uniformly without overpolishing.

Further, with respect to the semiconductor wafer horizontally held on the turntable, the Z direction which is the thickness direction of the semiconductor wafer, the X direction in the horizontal plane orthogonal to the Z direction and the X direction are orthogonal to the Z direction. 3 which can move in 3 directions of Y direction
A polishing plate shaft that is rotatable in a forward direction or a reverse direction is provided in the shaft moving mechanism, the polishing plate is fixed to the polishing plate shaft, and the polishing plate is moved in three directions while moving the polishing plate in three directions. Since the edge and the outer peripheral end face are brought into contact with each other, there is an effect that the edge of the semiconductor wafer can be polished automatically and efficiently by one edge polishing apparatus.

Further, a polishing plate shaft that is rotatable in a forward or reverse direction is provided in a three-axis moving mechanism that can move in three directions of the X and Y directions in the horizontal plane and the Z direction orthogonal to the horizontal plane. In addition, at least a pair of a first polishing plate whose outer peripheral portion has an obtuse angle substantially larger than a right angle and a second abrasive plate whose outer peripheral portion has a cross sectional shape close to a right angle. By arranging and fixing the polishing plate of
While moving the polishing plate in three directions, the edges of the outer peripheral portion of the semiconductor wafer are polished by the first polishing plate as described above, and the upper and lower edges of the V-shaped notch are polished by the up-cut by the first polishing plate. Then, the second polishing plate is alternately rotated in the forward direction and the reverse direction to polish the end face of the V-shaped notch. Therefore, the outer peripheral portion of the semiconductor wafer and the edge of the V-shaped notch can be polished by one edge polishing device. It has the effect of automatically polishing.

Further, the first polishing plate formed with an obtuse angle whose cross-sectional shape of the outer peripheral portion is considerably larger than the right angle on the polishing plate shaft arranged in the three-axis moving mechanism and the cross-sectional shape of the outer peripheral portion have an angle close to the right angle. Since the pair of polishing plates with the formed second polishing plate are fixed and configured as a unit, there is an effect that when the polishing plate is replaced, the unit as a whole can be easily replaced. As a result, it is possible to reduce the idle period of the edge polishing apparatus and efficiently polish the semiconductor wafer.

[Brief description of the drawings]

1 to 15 relate to an embodiment of the present invention.
FIG. 3 is a perspective view of an edge polishing apparatus for a semiconductor wafer.

FIG. 2 is a front view of an edge polishing apparatus for a semiconductor wafer.

FIG. 3 is a perspective view of a polishing plate device.

FIG. 4 is a front view of a polishing plate device.

FIG. 5 is a vertical cross-sectional view showing a state in which an upper surface side edge of a V-shaped notch is polished.

FIG. 6 is a perspective view showing a state in which an upper surface side edge of a V-shaped notch is polished.

FIG. 7 is a vertical cross-sectional view showing a state in which an end face of a V-shaped notch is polished.

FIG. 8 is a perspective view showing a state in which an end face of a V-shaped notch is polished.

FIG. 9 is a vertical cross-sectional view showing a state in which the lower surface side edge of the V-shaped notch is polished.

FIG. 10 is a perspective view showing a state in which the lower surface side edge of the V-shaped notch is polished.

FIG. 11 is a cross-sectional view showing a state in which the end face of the V-shaped notch is polished.

FIG. 12 is a cross-sectional view showing a state in which an upper surface side edge of a V-shaped notch is polished.

13A and 13B are a vertical cross-sectional view and a perspective view of a semiconductor wafer showing respective steps of processing a V-shaped notch in a semiconductor wafer.

FIG. 14 is a vertical cross-sectional view showing each step of polishing the edge of the V-shaped notch.

FIG. 15 is a vertical cross-sectional view showing the movement of the polishing plate when polishing a V-shaped notch.

16 to 21 relate to a conventional example, and FIG. 16 is a plan view and a vertical sectional view of a semiconductor wafer in which a V-shaped notch is formed.

FIG. 17 is a plan view and a vertical sectional view of a semiconductor wafer having an orientation flat formed therein.

FIG. 18 is a vertical cross-sectional view showing a state in which the edge of the semiconductor wafer is polished.

FIG. 19 is an enlarged vertical sectional view of an essential part showing a state where the edge of the semiconductor wafer is polished.

FIG. 20 is an enlarged perspective view of a main part of a semiconductor wafer that has been overpolished.

FIG. 21 is a vertical cross-sectional view of a semiconductor wafer showing a boundary line left unpolished.

[Explanation of symbols]

 Reference Signs List 10 semiconductor wafer edge polishing device 11 turntable 12 polishing plate 12A first polishing plate 12B second polishing plate 12a outer peripheral portion of edge polishing plate 13 reversible motor as an example of a driving device 14 three-axis moving mechanism 15 semiconductor wafer 15a outer peripheral end face 15b Edge 15c V-shaped notch 15d Upper surface side edge 15e Lower surface side edge 15f V-shaped notch end surface 16 Abrasive plate shaft 20 Mobile base

Claims (6)

[Claims] 1. In an edge polishing method for a semiconductor wafer, wherein a rotating polishing plate is brought into contact with an outer peripheral edge of the semiconductor wafer to polish the edge, the polishing plate comprises an axis extending in a direction perpendicular to a thickness direction of the semiconductor wafer. A first step in which the upper surface side edge of the semiconductor wafer is brought into contact with the upper surface side edge of the semiconductor wafer while being positively rotated from the outer peripheral direction of the semiconductor wafer toward the center direction by up-cut polishing as a center of rotation. A second step of bringing the polishing plate into contact with the outer peripheral end face of the semiconductor wafer and polishing the outer peripheral end face while rotating the polishing plate in the forward and reverse directions about the shaft as a rotation center; and rotating the polishing plate about the shaft. The bottom surface of the semiconductor wafer while rotating in the reverse direction so as to polish by up-cut from the outer peripheral direction of the semiconductor wafer toward the center as the center A third step of abutting against a side edge to polish the lower surface side edge, the edge of the semiconductor wafer is polished. 2. An edge polishing method for a semiconductor wafer, comprising polishing an edge by bringing an abrasive plate rotating around an axis in a direction perpendicular to a thickness direction of the semiconductor wafer as a rotation center into contact with an outer peripheral edge of the semiconductor wafer. A first step of abutting the upper surface side edge of the semiconductor wafer to polish the upper surface side edge while rotating the polishing plate forward from the outer peripheral direction of the semiconductor wafer toward the center direction so as to polish by upcut; A second step of bringing the polishing plate into contact with the outer peripheral end face of the semiconductor wafer and polishing the outer peripheral end face while rotating the polishing plate in the forward and reverse directions about the shaft as a rotation center; and rotating the polishing plate about the shaft. The bottom surface of the semiconductor wafer while rotating in the reverse direction so as to polish by up-cut from the outer peripheral direction of the semiconductor wafer toward the center as the center A third step of abutting against a side edge to polish the lower surface side edge, polishing the edge of the semiconductor wafer, and reciprocating the polishing plate in the axial direction of the shaft during polishing in each step. An edge polishing method for a semiconductor wafer, comprising: bringing the polishing plate into contact with the semiconductor wafer to polish the edge of the semiconductor wafer. 3. A semiconductor for polishing an edge of a V-shaped notch formed on the outer periphery of a semiconductor wafer by abutting a polishing plate which rotates about an axis perpendicular to the thickness direction of the semiconductor wafer as a rotation center. In the wafer edge polishing method, the first polishing plate having an obtuse angle whose cross-sectional shape of the outer peripheral portion of the polishing plate is considerably larger than a right angle is polished by up-cut from the outer peripheral direction of the semiconductor wafer toward the center direction. The first step of polishing the upper surface side edge of the V-shaped notch by abutting against the upper surface side edge of the V-shaped notch while rotating in the forward direction, and the cross-sectional shape of the outer peripheral portion of the polishing plate are formed at an angle close to a right angle. A second polishing plate is rotated in the forward and reverse directions about the shaft as a center of rotation and brought into contact with the end face of the V-shaped notch to polish the end face of the V-shaped notch. Step 2 and abutting against the lower surface side edge of the V-shaped notch while rotating the shaft in the reverse direction so as to polish the first polishing plate from the outer peripheral direction of the semiconductor wafer toward the center by upcut. And a third step of polishing the lower surface side edge of the V-shaped notch to polish the edge of the V-shaped notch of the semiconductor wafer. 4. A turntable for rotating a semiconductor wafer while holding it horizontally, and a polishing rotatably arranged on a movable table with its axis being perpendicular to and offset from the axis of rotation of the turntable. A polishing plate fixed to a plate shaft, a drive device for rotating the polishing plate together with the polishing plate shaft in the forward direction or the reverse direction, and the movable table in the Z direction, which is the thickness direction of the semiconductor wafer, and the Z direction. A three-axis moving mechanism configured to be movable in three directions of an X direction in a horizontal plane orthogonal to the X direction and a Y direction orthogonal to the X direction, and polishing by up-cut from the outer peripheral direction of the semiconductor wafer toward the center direction. While rotating the polishing plate in the forward direction, the polishing plate is brought into contact with the upper surface side edge of the semiconductor wafer to polish the upper surface side edge, and the polishing plate is alternately rotated in the forward and reverse directions. The lower surface of the semiconductor wafer is rotated by contacting the outer peripheral end surface of the semiconductor wafer to polish the outer peripheral end surface, and further rotating the polishing plate from the outer peripheral direction of the semiconductor wafer toward the center by up-cut polishing in the reverse direction. An edge polishing apparatus for a semiconductor wafer, which is configured to abut against a side edge to polish the lower surface side edge. 5. A turntable for rotating a semiconductor wafer while holding it horizontally, and a polishing rotatably arranged on a movable table with its axis being perpendicular to and offset from the axis of rotation of the turntable. At least a pair of polishing plates fixed to the plate shaft and having a first polishing plate whose outer peripheral portion has an obtuse angle which is substantially larger than a right angle and a second polishing plate whose outer peripheral portion has a cross sectional shape which is formed at an angle close to a right angle. A plate, a drive device for rotating the polishing plate together with the polishing plate axis in the forward direction or the reverse direction, the movable table in the Z direction which is the thickness direction of the semiconductor wafer, and X in a horizontal plane orthogonal to the Z direction. And a three-axis moving mechanism configured to be movable in three directions, which are the Y direction orthogonal to the X direction, and the first polishing plate is polished by upcut from the outer peripheral direction of the semiconductor wafer toward the center direction. The upper edge of the V-shaped notch while abutting against the upper edge of the V-shaped notch so as to polish the upper edge of the V-shaped notch, while rotating the second polishing plate alternately in the forward and reverse directions. While abutting against the end face of the V-shaped notch to polish the end face of the V-shaped notch, further rotating the first polishing plate from the outer peripheral direction of the semiconductor wafer toward the center toward the center by up-cut while reversely rotating. A semiconductor wafer, characterized in that the lower edge of the V-shaped notch is abutted to polish the lower edge of the V-shaped notch to polish the edge of the V-shaped notch of the semiconductor wafer. Edge polishing equipment. 6. A polishing plate that abuts against an edge of a semiconductor wafer while polishing the edge of the semiconductor wafer while rotating in the thickness direction of the semiconductor wafer, wherein a pair of outer peripheral portions are formed with obtuse angles which are considerably larger than right angles. An apparatus for polishing a semiconductor wafer, wherein a first polishing plate and a second polishing plate whose outer peripheral portion has a cross-sectional shape formed at an angle close to a right angle are fixed to a polishing plate shaft.