JPH1029142A - Mirror chamfering and machining method for disk semiconductor wafer chamfered section - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform mirror chamfering within a very short time while reducing the possibility of outer peripheral fractures by providing relative rotation while roughly the full periphery of the chamfered section of a disk semiconductor wafer is pressed to a recessed grinding surface and then performing the mirror chamfering of the chamfered section of the outer periphery. SOLUTION: First, a disk wafer 23 is fixed in a chuck 22. Then, after a moving base 16 is moved in a horizontal direction, and stopped a vertical moving shaft 18 is sent out and the disk wafer 23 is brought into contact with a grinding pad 5. Then, when the wafer 23 is further pressed by a specified pressure force, the full periphery of the chamfered section of the disk semiconductor wafer 23 is brought into contact with the grinding pad 5. In this state, grinding agents are supplied from a supply passage 7 to the upper surface of the grinding pad 5 and, by rotating a motor 11, a grinding base 4 is rotated via a rotary shaft 3. Thus, the chambered section of the disk semiconductor wafer 23 repeats relative movement while being pressed to the grinding pad 5, and uniform mirror grinding is performed for the chamfered section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for chamfering a semiconductor wafer which is a hard and brittle material, and more particularly to a method for chamfering an outer peripheral chamfer of a disc-shaped semiconductor wafer or, if necessary, an outer peripheral end thereof. The present invention relates to a processing method for performing chamfering polishing.

[0002]

2. Description of the Related Art Disc-shaped semiconductor silicon wafers have reached a level at which particles directly affect the improvement of the yield in the process. Similarly, the shift to larger diameters is progressing rapidly, and for this reason, it is desired that the outer periphery of the wafer substrate and the upper and lower chamfers be mirrored as well as the surface. It is done in such a way.

That is, Japanese Patent Application Laid-Open No. 64-71657 or Japanese Patent Application Laid-Open No.
As shown in Japanese Patent Application Laid-Open No. 4-71656, a disc-shaped semiconductor wafer 03 fixed with a suction chuck 02 is pressed onto the polishing drum 01 while rotating the polishing drum 01 having a polishing cloth 06 on the surface at a predetermined speed. The chamfered portion 07 of the semiconductor wafer 03 is subjected to mirror chamfering by pressing using a weight 04 or the like.

[0004] In this case, for example, a chamfered part 07 of about 22 mm is formed on the outer periphery of the semiconductor wafer 03 on both the front and back surfaces. Is formed. Therefore, in order to mirror-chamfer the chamfered portion 07, as shown in FIGS. 13 and 15, the disc-shaped semiconductor wafer 03 is pressed against the polishing drum 01 at an angle of, for example, 22 °, and the abrasive 05 While flowing.

[0005]

Therefore, as shown in FIGS. 14 and 15, the chamfered portion 07 of the disc-shaped semiconductor wafer 03 comes into line contact with the polishing pad 06 of the rotating drum 01 vertically (strictly). The mirror chamfering process is performed in a state of contact with a predetermined area by the elasticity of the polishing pad 06), so it takes time to perform the mirror chamfering process on the chamfered portion 07 on one side of the disc-shaped semiconductor wafer 03. I will. Therefore, for example, the pressing weight 04 is made heavy, and the semiconductor wafer 03 is moved to the rotating drum 0.
By strongly pressing the wafer, the pressurizing time can be reduced. However, since the semiconductor wafer 03 is thin and highly brittle, an excessive concentrated load is applied to the end of the semiconductor wafer 03 located on the outer periphery of the suction chuck 02. If it is added, a part will be lost, and there is a limit in increasing the mirror chamfering speed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and reduces the possibility of outer peripheral defects of a disk-shaped semiconductor wafer, which is a hard and brittle material, while mirroring the chamfered portion in an extremely short time. It is intended to provide a method capable of chamfering.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, a method for chamfering a mirror of a disk-shaped semiconductor wafer according to the present invention comprises the steps of: By giving a relative rotation between the polished surface and the disc-shaped semiconductor wafer in a state where the outer chamfer is pressed almost all around, the mirror chamfering of the outer chamfered portion of the disc-shaped semiconductor wafer is performed. It is characterized in that it is performed. The feature of the present invention is that the force for pressing the disc-shaped semiconductor wafer against the polished surface is supported using substantially the entire area of the chamfered portion located on the outer peripheral portion of the disc-shaped semiconductor wafer. Even if the pressing force, which is the most necessary for the mirror chamfering speed, is increased, a local load is not applied to the disk-shaped semiconductor wafer, thereby preventing local defects during the processing, and consequently chamfering the disk-shaped semiconductor wafer. This dramatically increases the mirror chamfering speed of the part. In this case, substantially the entire circumference means that notches are partially present in the disc-shaped semiconductor wafer or the polished surface, or that not all of the cuts have to be completely abutted due to a change in a part of the shape. doing. Further, the substantially entire circumference of the chamfered portion includes both circumferentially and circumferentially with respect to the polishing surface, which is determined by the elastic force of the polishing surface.

In the mirror chamfering method for a chamfered portion of a disc-shaped semiconductor wafer according to the present invention, the outer peripheral chamfered portion of the disc-shaped semiconductor wafer has a radius of curvature which can be pressed over almost the entire circumference as a concave polished surface. It is preferable to use a spherical inner surface shape. This is because the spherical inner surface shape is easily determined by calculating the radius of curvature of the spherical inner surface shape as a polishing surface based on the diameter of the disk-shaped semiconductor wafer, and in this way, the disk-shaped semiconductor wafer is polished into a concave shape. By simply contacting the surface, theoretically the entire circumference of the disc-shaped semiconductor wafer always hits the polished surface, and the setting of the positions of the two is extremely simplified.

According to the method for chamfering a mirror of a disk-shaped semiconductor wafer according to the present invention, the rotation axis of the disk-shaped semiconductor wafer is made coincident with the center point of the inner surface of the sphere which is the polishing surface, and It is preferable that the rotation axis of the disc-shaped semiconductor wafer is made not to coincide with each other, and at least the polished surface is forcibly rotated by the rotation axis. By doing so, the chamfered portion of the disc-shaped semiconductor wafer comes into contact with the polished surface having a spherical inner surface over a wide area, so that the life of the polished surface is extended.

In the method for chamfering a mirror of a disc-shaped semiconductor wafer according to the present invention, the concave-shaped polishing surface has a conical inner surface shape capable of pressing the chamfer on the outer periphery of the disc-shaped wafer substantially all around. It is preferable to use a part. By doing so, it becomes possible to reliably apply a conical surface having an opening angle of the same angle to a chamfered portion having an inclination angle (for example, 22 °) formed on the front and back surfaces of the disc-shaped semiconductor wafer, Mirror chamfering processing of the chamfer can be performed with high accuracy.

In the method for chamfering a mirror of a disc-shaped semiconductor wafer according to the present invention, one surface of a disc-shaped semiconductor wafer is fixed to a pressure plate, and the other chamfer is pressed against a polishing surface by the pressure plate. Contact, perform the mirror chamfering of the chamfered portion of the other surface for a predetermined time, then remove the processing plate from one surface of the disk-shaped semiconductor wafer, and then fix the other surface of the disk-shaped semiconductor wafer to the pressure plate, Preferably, one chamfered portion is pressed against a pressure plate, and the mirror chamfering of the one chamfered portion is performed for approximately the same time as the mirror chamfering time of the other surface. In the case of the present invention, basically all the chamfered portions on one side are in contact with the polished surface during the mirror chamfering process, and the finishing accuracy cannot be confirmed. Mirror chamfering becomes possible.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 3 show a first embodiment, and FIGS.
FIG. 11 shows the second to ninth embodiments, and FIG. 12 shows the tenth embodiment.

A first embodiment will be described with reference to FIGS. 1 to 3. Reference numeral 1 denotes a bed, and a rotary shaft 3 extends upward from a bearing 2 extending from below the bed 1 via a bearing. A bowl-shaped polishing table 4 constituting a concave polishing surface is fixed to the upper end of the rotating shaft 3. Further, the inner surface of the concave portion of the polishing table 4 is a spherical surface centered on a point P having a predetermined height, and a polishing pad 5 such as a nonwoven fabric is fixed to the inner surface of the concave portion. Specifically, as shown in FIG. 2, grooves 6 extend upward at predetermined intervals, and serve as a flow path of an abrasive, which will be described later. Alternatively, the polishing table 4 may be discharged from the edge of the polishing table 4 by centrifugal force generated by the rotation of the polishing table 4.

In the center of the rotating shaft 3, a supply passage 7 for abrasive supplied from below is formed, which penetrates through the polishing table 4 and the polishing pad 5, and supplies the abrasive to the upper surface of the polishing pad 5. I can do it.

A pulley 8 is fixed to the lower end of the rotating shaft 3 so that the rotating shaft 3 and the polishing table 4 can be rotated by a rotational driving force from a motor 11 via a motor pulley 10 and a belt 9.

A column 12 extends upward from the bed table 1. The column 12 is provided with a feed screw 15 which is rotated by a motor 14. The feed screw 15 slides left and right through a slide rail 13. A moving table 16 that moves is provided. A pressurizing cylinder 17 is provided above the moving table 16, and an elevating shaft 18 is suspended from the pressurizing cylinder via a bearing 19. A chuck 22 is provided at the end of the elevating shaft 18 via a universal joint 20 and a rotary bearing 21. The chuck 22 has a wide flat plate shape, functions as a pressurizing plate, and is supported by a rotary bearing 21 so as to be rotatable with respect to the universal joint 20. Note that a disc-shaped semiconductor wafer 23 is fixed to the lower surface of the chuck 22 by means such as suction and sticking of the chuck 22.

The operation and operation of the mirror chamfering polishing process for a disc-shaped semiconductor wafer according to this embodiment will be described.

First, the chuck 22 is located at an upper portion as shown by a two-dot chain line, and a disk-shaped semiconductor wafer 23 is fixed to the chuck 22 here. Next, the motor 14 is driven to rotate the feed screw 15, and the moving table 16 is moved laterally to stop it. Then, the pressurizing cylinder 17 is driven to feed out the elevating shaft 18 until the state shown in FIG. Then, the disc-shaped semiconductor wafer 23 is brought into contact with the polishing pad 5 which is a polishing surface, and is further pressed with a predetermined pressing force. Since the polishing pad 5 such as a nonwoven fabric has a slight elastic force due to the pressing force, the chamfered portion of the disc-shaped semiconductor wafer 23 comes into contact with the polishing pad 5 over almost the entire circumference. In this case, the radius of the spherical surface of the polishing pad 5 (that is, the position of the point P) may be selected so that the surface of the chamfered portion and the tangential direction of the ball of the polishing pad 5 which is the inner surface of the ball coincide with each other. .

In this state, the polishing agent is supplied from the supply passage 7 to the upper surface of the polishing pad 5, and the motor 11 is rotated to rotate the polishing table 4 via the rotating shaft 3.

The polishing table 4 rotates the polishing pad 5 in the direction of arrow A, and the polishing pad 5 and the disc-shaped semiconductor wafer 23 are rotated.
A frictional force of a different vector is applied to the chamfered portion over substantially the entire circumference depending on the contact position. That is, as shown in FIG. 3, a large vector rotational force is generated at point C and a small vector rotational force is generated at point D of the disc-shaped semiconductor wafer 23, and the central axis O and the central point O ′ do not coincide. As described above, the co-rotating force is applied to the disc-shaped semiconductor wafer 23 by the arrow B.
Occurs in the direction.

Therefore, the chamfered portion of the disc-shaped semiconductor wafer 23 repeatedly moves relative to the polishing pad 5 in a pressed state,
Uniform mirror chamfer polishing of the chamfered portion is performed. If the center axis O and the center point O ′ are not made to coincide with each other, the area of the polishing pad 5 used for the mirror chamfering of the chamfered portion increases as shown by the hatched portion in FIG. The life of the pad 5 can be significantly extended.

Further, since the force for pressing the disc-shaped semiconductor wafer 23 against the polishing pad 5 is supported using substantially the entire chamfered portion located on the outer peripheral portion of the disc-shaped semiconductor wafer 23, the mirror chamfer is performed. Even if the pressing force most necessary for the processing speed is increased, a local load is not applied to the disc-shaped semiconductor wafer 23, so that local loss during processing can be prevented. In addition, the mirror chamfering speed of the chamfered portion of the disc-shaped semiconductor wafer is drastically increased. Furthermore, if the shape of the polished surface is spherical, even if the position of the disc-shaped semiconductor wafer 23 is displaced during setting or during mirror chamfering polishing, there is no effect on the mirror chamfering of the chamfered portion, Excellent mirror chamfering while maintaining the inclination angle of the chamfered portion can be performed.

When the one-sided mirror chamfering is completed, the disc-shaped semiconductor wafer 23 is removed from the chuck 22, and the other side of the disc-shaped semiconductor wafer 23 is chamfered. Mirror chamfering is completed.

FIG. 4 shows a second embodiment of the present invention,
8 is the center point O 'of the disc-shaped semiconductor wafer 23 and the polishing table 4
Shaft 1 that is fixed and does not rotate
Semiconductor wafer 2 on chuck 22 fixed to
3, the polishing table 4 is rotated, and the polishing pad cannot be used over a wide range of surfaces.
The setting at the time of machining can be performed only by the vertical movement of 8, which leads to shortening of machining time.

FIG. 5 shows a third embodiment in which the fixed and non-rotating elevating shaft 18 is also made unrotatable with respect to the chuck 22. In this case, as in the first embodiment, the life of the polishing pad 5 can be extended.

FIG. 6 shows a fourth embodiment, which is a combination of the second and third embodiments. The disk is formed at a predetermined timing by a swing shaft 181 which does not rotate using a driving unit 25. The position of the semiconductor wafer 23 is changed with respect to the polishing pad 5. In this case, not only the setting is easy, but also the life of the polishing pad 5 can be extended.

FIG. 7 shows a fifth embodiment in which the chuck 22 itself is rotated with respect to the polishing pad 5, and the motor 22 rotates the chuck 22 together with the rotating shaft 182, so that the polishing table 4 is supported. It is fixed at 31. In this case, the axis of the support 31 and the axis of the rotation axis 182 coincide.

FIG. 8 shows a sixth embodiment in which both axes of the fifth embodiment are not coincident with each other, and the effect is the same as that of FIG.

FIG. 9 shows a seventh embodiment, which is a combination of the fifth and sixth embodiments, in which the rotating shaft 182 rotating by using the drive unit 25 is moved at a predetermined timing. By swinging, the position of the disc-shaped semiconductor wafer 23 is changed with respect to the polishing pad 5, and the life of the polishing pad 5 can be extended.

FIG. 10 shows an eighth embodiment in which both the chuck 22 and the polishing table 23 are forcibly rotated, and the relative rotational speed of both can be increased.

FIG. 11 shows a ninth embodiment in which a polishing pad 5 and a polishing table 41 as polishing surfaces are partially formed in a conical surface, and are formed on the front and back of a disc-shaped semiconductor wafer 23. The angle is the same as that of the chamfered portion having the inclination angle, so that the mirror chamfering processing of the chamfered portion can be performed with high accuracy. Here, the inclination angle of the chamfer is 22 °,
Since there are a plurality of types such as 11 °, a polishing table 41 and a polishing pad 51 that match this angle may be prepared.

FIG. 12 shows a tenth embodiment.
The embodiment differs from the embodiment in that an annular convex portion 2 for chamfering and polishing the outermost end portion on the upper peripheral portion of the polishing pad 5 is provided.
4 is formed. Such an annular convex portion 2
If 4 is provided, the outermost peripheral end as well as the chamfered portion can be mirror-chamfered at the same time.

Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and even if there are changes and additions without departing from the gist of the present invention. Included in the invention. For example, in the embodiment, the chamfered portion is expressed as a flat portion having an inclination angle of 22 °, 11 °, or the like, but there is also a curved surface, and for example, the outermost end and the chamfered portion are all round surfaces. Is included.

[0034]

According to the present invention, the following effects can be obtained.

(A) According to the first aspect of the present invention, the force for pressing the disc-shaped semiconductor wafer against the polished surface is supported by using substantially the entire area of the chamfer located at the outer peripheral portion of the disc-shaped semiconductor wafer. Even if the pressing force, which is the most necessary for the mirror chamfering speed, is increased, a local load is not applied to the disc-shaped semiconductor wafer, and local defects can be prevented during the processing. This is to dramatically increase the mirror chamfering speed of a chamfered portion of a semiconductor wafer.

(B) According to the second aspect of the present invention, the radius of curvature of the spherical inner surface shape as the polishing surface is calculated based on the diameter of the disc-shaped semiconductor wafer, so that the spherical inner surface shape is easily determined. By just contacting the disc-shaped semiconductor wafer with the concave polishing surface, the entire circumference of the disc-shaped semiconductor wafer always hits the polishing surface at all times theoretically,
The setting of both positions is greatly simplified.

(C) According to the third aspect of the present invention, the chamfered portion of the disc-shaped semiconductor wafer abuts on the polished surface having a spherical inner surface over a wide area, thereby extending the life of the polished surface.

(D) According to the invention of claim 4, the inclination angle (for example, 22 degrees) formed on the front and back of the disc-shaped semiconductor wafer.
The conical surface having the same angle of opening can be reliably applied to the chamfered portion ゜), and the mirror chamfering process of the chamfered portion can be performed with high accuracy.

(E) According to the invention of claim 5, basically, all the chamfered portions on one side are in contact with the polished surface during the mirror chamfering, and the finishing accuracy cannot be confirmed. Mirror chamfering of the chamfered part with the same accuracy on both sides is possible.

[0040]

[Brief description of the drawings]

FIG. 1 is a partial sectional view of an apparatus showing a first embodiment.

FIG. 2 is a partial perspective view of FIG.

FIG. 3 is a plan view of the polishing surface of FIG. 2;

FIG. 4 is a schematic diagram showing a second embodiment.

FIG. 5 is a schematic diagram showing a third embodiment.

FIG. 6 is a schematic diagram showing a fourth embodiment.

FIG. 7 is a schematic view showing a fifth embodiment.

FIG. 8 is a schematic diagram showing a sixth embodiment.

FIG. 9 is a schematic view showing a seventh embodiment.

FIG. 10 is a schematic view showing an eighth embodiment.

FIG. 11 is a schematic view showing a ninth embodiment.

FIG. 12 is a schematic view showing a tenth embodiment.

FIG. 13 is a schematic view showing a conventional device.

FIG. 14 is a plan view of FIG.

FIG. 15 is a local view showing a chamfer portion and a polishing drum of FIG. 13;

[Explanation of symbols]

 1 Bed stand 2 Bearing 3 Rotary shaft 4 Polishing table 5 Polishing pad 6 Groove 7 Supply passage 8 Pulley 9 Belt 10 Motor pulley 11 Motor 12 Column 13 Sliding rail 14 Motor 15 Feed screw 16 Moving table 17 Pressure cylinder 18 Elevating shaft 19 Bearing DESCRIPTION OF SYMBOLS 20 Universal joint 21 Rotation bearing 22 Chuck 23 Semiconductor wafer 24 Annular convex part 31 Supporter 41 Polishing table 51 Polishing pad 181 Swing axis 182 Rotation axis

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuo Hirabayashi 3-6-22, Yawatacho, Higashikurume-shi, Tokyo Asahisaka Abrasive Processing Co., Ltd. (72) Inventor Keiji Honda 3 Yawatacho, Higashikurume-shi, Tokyo Chome 6-22 Asahi Sakae Polishing Co., Ltd.

Claims (5)

[Claims] In a state where a chamfered portion on the outer periphery of a disc-shaped semiconductor wafer is pressed substantially all around the concave-shaped polishing surface, relative rotation between the polishing surface and the disc-shaped semiconductor wafer is controlled. A mirror chamfering method for a chamfered portion of a disc-shaped semiconductor wafer, wherein a mirror chamfering process for a chamfered portion on an outer periphery of the disc-shaped semiconductor wafer is performed. 2. The disc-shaped semiconductor wafer according to claim 1, wherein the concave-shaped polished surface has a spherical inner surface shape having a radius of curvature capable of pressing the outer peripheral chamfered portion of the disc-shaped semiconductor wafer substantially all around. Mirror chamfering method for chamfered part. 3. The polishing machine according to claim 1, wherein the rotation axis of the disc-shaped semiconductor wafer is made coincident with the center point of the inner surface of the sphere, which is a polishing surface, and the polishing surface, the rotation axis and the rotation axis of said disc-shaped semiconductor wafer are not coincident with each other. 3. The mirror chamfering method for a disk-shaped semiconductor wafer chamfered part according to claim 2, wherein the surface is forcibly rotated about its rotation axis. 4. The disk-shaped semiconductor wafer surface according to claim 1, wherein the concave polishing surface is a part of a conical inner surface shape capable of pressing a chamfered portion on an outer circumference of the disk-shaped wafer substantially all around. Mirror chamfering method for the bevel. 5. A surface of a disc-shaped semiconductor wafer is fixed to a pressure plate, and a chamfered portion of the other surface is pressed against a polishing surface by a pressure plate, and a mirror chamfering process of the chamfered portion of the other surface is performed. Time, then remove the working plate from one surface of the disc-shaped semiconductor wafer, then fix the other surface of the disc-shaped semiconductor wafer to the pressure plate, press the chamfer of one surface against the pressure plate, 5. The mirror chamfering method for a disk-shaped semiconductor wafer chamfer according to claim 1, wherein the mirror chamfering of the chamfered portion is performed for substantially the same time as the mirror chamfering time of the other surface. .