JPH0752014A - Glassily grinding method for notch part of semiconductor-wafer and device therefor - Google Patents

Abstract

PURPOSE:To effectively grind glassily the notch part provided on the peripheral edge of a semiconductor-wafer by bring a cord-like grinding member into abutment on the notch part and relatively pressing both the grinding member and the notch part to move the cord-like grinding member. CONSTITUTION:When the notch part of a semiconductor-wafer 30 is ground glassily, the wafer 30 is sucked and held by a holding part 28 so that the notch part is right in front of the cord-like grinding member 12, and the cord-like grinding member 12 travels by the driving of a forward-reverse controlling motor. Then, a cylinder device is driven in order for the notch part 32 of the wafer 30 held on the holding part 28 through a turning arm to abut on the cord-like grinding member 12. At this time, in order for the wafer 30 to press and move the cord-like grinding member 12 between regulating rollers 20, 20 to specified distance against the pressing force of the cylinder device 18, the cord-like grinding member 12 is deformed into an about V-shape at the pressed part. Thus, the entire end face in the notch part of the wafer 30 is evenly ground, and the pressing force of the grinding member 12 is adjusted by the cylinder device 18.

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 mirror-polishing a notch portion of a semiconductor wafer.

[0002]

2. Description of the Related Art In the case of semiconductor wafers made of silicon or the like, it is necessary to clarify the direction of the crystal axis in processing semiconductor chips. In order to indicate the direction of the crystal axis, an orientation flat (so-called orientation flat) is formed by cutting out a part of a circular wafer in the direction of the crystal axis, or a notch is formed by simply cutting out the peripheral edge of the wafer into a small V-shape. I'm wondering. In recent years, the diameter of wafers has increased, and wafers having a diameter of 8 inches have appeared. In such a large-diameter wafer, the notch portion tends to be provided because the use of the orientation flat causes a large amount of wasteful portions to be discarded.

[0003]

The silicon wafer is
High-precision surface processing is required, and especially in the polishing process, even the generation of fine dust can greatly affect the processing quality.Therefore, the device itself is installed in equipment such as a dust-free room, Dustproof measures are taken. The wafer surface is lapped before polishing, but if the outer periphery of the wafer is ground, dust and other substances tend to adhere.If processed in this state, the attached dust may fall off, If the rough surface of is cut off, the processing quality will deteriorate. Therefore, it is required that the outer peripheral portion of the wafer be mirror-polished. As for the mirror-polishing of the orientation flat portion, the technique disclosed in JP-A-5-102111 is known. In the case where the notch portion is provided, since the notch portion is small as described above, there is not much influence of dust generation, and the notch portion was used without polishing. It also depends on the difficulty of polishing the small notch. However, since the semiconductor chips are becoming more highly integrated, even a small amount of dust has a great influence on the semiconductor chips, and the notch portion is also required to be mirror-polished.

The present invention has been made in order to meet the above-mentioned demand, and an object of the present invention is to provide a method and an apparatus capable of effectively mirror-polishing a notch portion.

[0005]

The present invention has the following constitution in order to achieve the above object. That is, the method of the present invention is
The strap-shaped polishing member is brought into contact with the notch portion provided on the peripheral edge of the chamfered semiconductor wafer, and the strap-shaped polishing member is moved by relatively pressing the wafer and the strap-shaped polishing member. It has a feature. At that time, it is preferable that the strap-shaped polishing member is made to travel in the forward and reverse directions. Further, in the device of the present invention, the traveling device for traveling the string-shaped polishing member, the holding portion for holding the wafer, and the traveling device and the wafer held by the holding part are relatively brought into contact with each other to separate the string-shaped polishing member. The present invention is characterized by comprising a pushing device for bringing the member into contact with a notch portion provided on the peripheral edge of the wafer and for pressing the string-like polishing member against the inner end surface of the notch portion, and a supply device for supplying the abrasive. It is preferable to provide a pair of regulating rollers that come into contact with the string-like polishing member with the contact portion sandwiched therebetween from the side opposite to the portion where the wafer notch portion comes into contact, and at which the distance between the two can be freely adjusted. The holding part is attached to a rotating arm, and the rotating arm moves the wafer held by the holding part in the direction of the string-shaped polishing member, and the string-shaped polishing member is placed in a notch part provided on the periphery of the wafer. It is preferable to provide a biasing means for bringing the string-like polishing member into contact with the inner end surface of the notch. In this case, it is preferable to provide a stopper that restricts the rotation range of the rotation arm toward the string-shaped polishing member. It is preferable to provide a moving device that moves the wafer within the width of the notch of the wafer while holding the wafer. It is preferable that the traveling device is provided with a tension adjusting means for adjusting the string-shaped polishing member to a predetermined tension.

[0006]

[Operation] A strap-shaped polishing member is brought into contact with the notch portion provided on the periphery of the chamfered semiconductor wafer,
By pressing the wafer and the string-shaped polishing member relative to each other, the string-shaped polishing member is pushed until it becomes almost V-shaped, and the string-shaped polishing member is not only the center flat part of the inner end face of the notch but also the chamfered part. At the same time, the string-shaped polishing member is run in this state, whereby the entire inner end surface of the notch can be uniformly polished. If the string-shaped polishing member does not come into contact with the entire width direction of the inner end face of the notch due to the thickness of the string-shaped polishing member, the size of the notch, etc., the wafer is moved within the width of the notch. The flat polishing member can be brought into contact with the entire inner surface of the notch portion, and uniform mirror polishing of the entire inner end surface of the notch portion can be performed. By changing the distance between the pair of regulating rollers or adjusting the range of rotation of the rotating arm toward the string-shaped polishing member, the contact angle of the string-shaped polishing member with the notch can be adjusted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Since the method of the present invention is in line with the apparatus of the present invention, an embodiment of the method invention will be described together with an embodiment of the apparatus invention. 1 is a schematic front view, FIG. 2 is a plan view,
FIG. 3 is a side view. Reference numeral 10 denotes a traveling device, which is an endless string-shaped polishing member 12 having four grooved pulleys 14a, 14a.
It is hung on b, 14c, 14d and can rotate in the vertical plane. The pulley 14a is a drive pulley and is driven by the forward / reverse motor 16. Pulley 14
b, 14c and 14d are idle pulleys. As shown in FIG. 4, the strap-shaped polishing member 12 is preferably a wire 12a whose peripheral surface is coated with urethane foam containing an abrasive. Reference numeral 18 denotes a cylinder device showing an example of tension adjusting means. A pressing roller 18a is provided at the rod end of the cylinder device. The pressing roller 18a abuts the string-shaped polishing member 12 and is urged by the cylinder device 18 to perform string-shaped polishing. A predetermined tension is applied to the member 12. The cylinder device 18 is composed of, for example, an air cylinder, and the tension of the string-shaped polishing member 12 can be varied by adjusting the air pressure with a regulator (not shown).
Instead of the cylinder device, a tension roller biased by a spring may be used to apply a predetermined tension to the string-shaped polishing member 12. Reference numerals 20 and 20 denote a pair of regulating rollers, which are arranged corresponding to the holding portion 28 and are arranged so as to come into contact with the string-shaped polishing member 12 at regular intervals. The space between the two regulation rollers 20, 20 can be adjusted by an adjusting device (not shown). The adjusting device can be configured, for example, by guiding the rotation shafts of both the regulation rollers 20 and 20 into the long holes and tightening and fixing them at appropriate positions of the long holes.

Reference numeral 22 is a rotary arm, and the rotary shaft 23 is a base 2
It is rotatably provided in the horizontal plane by being supported by the bearing 25 provided on the No. 4 bearing. Reference numeral 26 is a cylinder device showing an example of the urging means, and the rod end is connected to one end side of the rotating arm 22 so that the rotating arm 22 can rotate in a horizontal plane in the illustrated example. A spring, a weight or the like may be adopted instead of the cylinder device 26. Reference numeral 27 denotes a stopper bolt, which can adjust the turning range of the turning arm 22. The rotating arm 22, the biasing means, and the like constitute a pushing device. A holding portion 28 is provided on the tip end side of the rotating arm 22. The holding portion 28 sucks the wafer 30 on its lower surface side and holds the wafer 30 so that the peripheral portion of the wafer 30 is exposed. Reference numeral 32 denotes a notch portion formed on the peripheral edge of the wafer 30. As shown in FIG. 5, the notch portion 32 has chamfered portions 32a formed at both edges thereof, and a central flat portion 32b is provided between the doublet chamfered portions 32a. Reference numeral 34 denotes a forward / reverse motor, and its rotation shaft is connected to the holding portion 28 to rotate the holding portion 28 in the forward / reverse direction while sucking the wafer 30. FIG. 6 shows an example of a specific example of the holding unit 28 and its rotating mechanism. That is, the rotation shaft 36 is connected to the output shaft 35 of the forward / reverse motor 34 via a speed reduction mechanism (not shown) as appropriate, and the suction plate 37 is fixed to the lower end of the rotation shaft 36. A ring-shaped seal 38 is attached to the lower surface of the suction plate 37. A suction hole 39 is provided at the center of the suction plate 37.
The suction hole 39 is connected to a suction device (not shown) through a communication hole 40 provided in the rotary shaft 36, a joint 41 into which the rotary shaft 36 is rotatably inserted, and a hose 42. There is. Therefore, the wafer 30 is attached to the suction plate 37.
Can be suction-held, and the suction plate 37 can be normally and reversely rotated by the forward / reverse motor 34 while the wafer 30 is suction-held, and thus the wafer 30 can be normally and reversely rotated. The forward / reverse motor 34 constitutes a rotating device of the holding portion 28.

The present embodiment is constructed as described above.
Next, the operation will be described. First, the wafer 30 as described above
Is held by suction with the holding portion 28 so that the notch portion 32 faces the string-shaped polishing member 12. The forward / reverse motor 16 is driven to drive the string-shaped polishing member 12. At that time, it is needless to say that a predetermined tension is applied to the string-shaped polishing member 12 by the cylinder device 18. Next, the cylinder device 26 is driven to rotate the rotating arm 22 in the arrow X direction by projecting the rod, and the notch 32 of the wafer 30 held by the holder 28 is brought into contact with the string-like polishing member 12. Let The rotation arm 22 is rotated at a predetermined rotation angle until it comes into contact with the stopper bolt 27, and the wafer 30 moves to the regulation roller 2 as shown in FIGS.
The string-shaped polishing member 12 between 0 and 20 is pushed a predetermined distance against the pressing force of the cylinder device 18, and the string-shaped polishing member 12 is pushed until it becomes substantially V-shaped. As a result, as clearly shown in FIG. 7, the string-shaped polishing member 12 simultaneously abuts not only the central flat portion 32b of the inner end surface of the notch portion 32 but also the chamfered portion 32a and uniformly polishes the entire inner end surface of the notch portion 32. . Figure 7
As shown in, the thickness of the string-shaped polishing member 12 and the notch portion 3
The string-shaped polishing member 12 is notched 32 depending on the size of the two.
If the inner end face does not come into contact with the entire width direction, the forward / reverse motor 3
By driving 4 to rotate the wafer 30 within the width of the notch portion 32, the string-shaped polishing member 12 can be brought into contact with the entire width of the notch portion 32. Allows uniform mirror polishing of the entire surface. In order for the strap-shaped polishing member 12 to effectively contact the chamfered portion 32a of the inner end surface of the notch portion 32, the rotation range of the rotation arm 22 and the distance between the regulation rollers 20, 20 are related. Therefore, the rotation range of the rotation arm 22 is adjusted by the stopper bolt 27, and the distance between the regulation rollers 20, 20 is adjusted appropriately. If the V-shaped angle of the string-shaped polishing member 12 is shallow, the string-shaped polishing member 12 does not contact the chamfered portion 32a, and uniform polishing cannot be performed.
Is abutted on the front surface side of the wafer 30 and over-polished. It is also important to adjust the pressing force of the cylinder device 18. This is because the pressing force determines the pressing force applied to the inner end surface of the notch portion 32 of the string-shaped polishing member 12.

Incidentally, the string-like polishing member 12 has the chamfered portion 32a.
If the wafer 30 is not sufficiently contacted, the wafer 30 may be rotated about the notch 32 in the UV direction of FIG. Further, in the above, the wafer 30 is moved to the notch portion 3 by the forward / reverse motor 34.
Although the wafer 30 is rotated within the width range of 2, the wafer 30 may be linearly moved within the width range of the notch portion 32 by an appropriate mechanism. The concept of the moving device according to claim 7 is a concept including rotation and linear movement. In the above description, the string-shaped polishing member 12 is made to travel back and forth, but it may be run in only one direction. Further, the string-like polishing member 12 may be of a winding type so as to be reciprocated instead of being endless. In the above-described embodiment, the wafer 22 is positioned in the horizontal plane and the string-shaped polishing member 12 is rotated in the vertical plane. However, this arrangement direction is not limited. For example, the wafer 30 is set in the vertical plane. It can be configured to hold and place the traveling device side in its peripheral portion.

[0011]

According to the method and apparatus of the present invention, the wafer and the string-shaped polishing member are relatively pressed to move the string-shaped polishing member while pressing the string-shaped polishing member against the inner end surface of the notch. Therefore, the string-shaped polishing member can be uniformly brought into contact with the chamfered portion of the inner end surface of the notch portion, and the inner end surface of the small notch portion can be uniformly and efficiently mirror-polished.
Further, by moving the wafer within the width of the notch, the entire surface of the notch can be mirror-polished. Further, by adjusting the tension of the string-shaped polishing member by the tension adjusting means, the optimum polishing force can be set. Also, by changing the distance between the pair of regulation rollers and adjusting the range of rotation of the rotating arm toward the strap-shaped polishing member, the contact angle of the strap-shaped polishing member with the notch can be adjusted, making it possible to make a fine adjustment. Can perform various polishing processes.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a wafer polishing apparatus.

FIG. 2 is a plan view of the polishing apparatus shown in FIG.

FIG. 3 is a side view of the polishing apparatus shown in FIG.

FIG. 4 is a cross-sectional explanatory view of a string-shaped polishing member.

FIG. 5 is a sectional view of a wafer notch portion.

FIG. 6 is a partial cross-sectional view of a wafer holder.

FIG. 7 shows a polishing principle diagram.

[Explanation of symbols]

 10 Traveling device 12 String-shaped polishing member 14 Pulley 16 Forward / reverse motor 18 Cylinder device 20 Regulation roller 22 Rotating arm 26 Cylinder device 27 Stopper bolt 28 Holding part 30 Wafer 32 Notch part 34 Forward / reverse motor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuuo Nakamura 1650 Kiyono, Matsushiro-cho, Nagano City, Nagano Prefecture Fujikoshi Machine Industry Co., Ltd. Within

Claims (8)

[Claims] 1. A strap-shaped polishing member is brought into contact with a notch portion provided on the peripheral edge of a chamfered semiconductor wafer, and the wafer and the strap-shaped polishing member are relatively pressed to each other. A method for mirror-polishing a notch of a wafer, which comprises: 2. The mirror-polishing method for a wafer notch portion according to claim 1, wherein the string-shaped polishing member is run in forward and reverse directions. 3. A string-shaped polishing member, wherein a running device for moving a string-shaped polishing member, a holding part for holding a wafer, and a wafer held by the running device and the holding part are relatively brought into contact with and separated from each other. The wafer notch characterized in that it comprises a pushing device for abutting the inside of the notch part provided on the peripheral edge of the wafer and for pushing the string-like polishing member against the inner end face of the notch part, and a supply device for supplying the abrasive. Mirror polishing equipment. 4. A pair of regulating rollers are provided from the side opposite to the portion where the wafer notch portion abuts, abutting against the string-shaped polishing member with the abutting portion sandwiched therebetween, and the distance between them can be freely adjusted. The mirror polishing device for a wafer notch portion according to claim 3, wherein 5. The holding unit is attached to a rotating arm, and the rotating arm moves the wafer held by the holding unit in the direction of the string-shaped polishing member, and the string-shaped polishing member is provided on the peripheral edge of the wafer. Abut the inside of the notch,
5. The wafer according to claim 3, wherein a biasing means for pressing the strap-shaped polishing member is arranged on the inner end surface of the notch portion, and the pushing device is constituted by the rotating arm and the biasing means. Mirror polishing device for notch. 6. The mirror polishing device for a wafer notch portion according to claim 5, further comprising a stopper for restricting a rotation range of the rotation arm toward the string-shaped polishing member. 7. A moving device for moving the holding portion within a width of a notch portion of the wafer while holding the wafer is provided.
A mirror-polishing device for the wafer notch portion described. 8. The mirror polishing of the wafer notch portion according to claim 3, wherein the traveling device comprises a tension adjusting means for adjusting the string-shaped polishing member to a predetermined tension. apparatus.