JPH03138933A - Polishing device - Google Patents

Abstract

PURPOSE:To prevent roughening of the polished surface of the outer surface region of a material caused by crevice corrosion and the like by providing a structure wherein the profile of each mounting hole formed in a template has a false circular shape. CONSTITUTION:A plurality of projections 8b are formed at the inner surface part of each mounting hole 8a of a template 8 surrounding each material to be polished 11. The projections are arranged at an intended interval in the circumferential direction. The tip part of the projection 8b which is directed toward the central part is approximately in contact with the outer surface part of the material to be polished 11. In this structure, a sufficiently wide groove 8c is formed between the outer surface of the material to be polished and the inner surface of the mounting hole 8a in the mounting state of the material to be polished 11. Therefore, the flowing state of polishing liquid becomes excellent. The progress of the crevice corrosion of the polished material 11 caused by the stagnation of the polishing liquid and the like in fine crevices is avoided. Roughening of the polished surface at the outer surface region of the material to be polished 11 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polishing technique, and particularly to a technique that is effective when applied to mirror polishing of semiconductor substrates and the like.

[Conventional technology]

For example, in the manufacture of semiconductor substrates used in the manufacturing process of semiconductor integrated circuit devices, mirror polishing is applied to the main surface on which circuit patterns are transferred and formed in order to ensure a high level of flatness. is being carried out.

Conventionally, as one of the polishing techniques for performing such polishing processing, for example, Kogyo Kenkyukai Co., Ltd., published November 20, 1985, "Electronic Materials" November 1985 issue special issue P4
There is a waxless type boring device described in documents such as No. 1 to P49.

That is, a template in which a plurality of mounting holes slightly larger than the outer diameter of the semiconductor substrate are formed is fixed to a polishing plate provided opposite to a polishing surface plate covered with a polishing cloth, and individual holes are attached to the polishing plate. An elastic porous film is placed in the center of the mounting hole using double-sided tape or the like, and the thickness of the template is smaller than the sum of the thicknesses of the semiconductor substrate and the elastic porous film.

After adsorbing and fixing the semiconductor substrate by pressing the back side of the semiconductor substrate against the moistened elastic porous film,
By pinching the semiconductor substrate between a polishing plate and a polishing surface plate, and supplying a desired alkaline polishing agent, for example, by relatively displacing the two within the opposing surfaces,
The polishing work is performed by sliding the polished surface of the semiconductor substrate on a polishing cloth, and by supporting each semiconductor substrate from the circumferential direction by the inner periphery of the mounting hole of the template, it is possible to prevent misalignment of the semiconductor substrate in the radial direction. It is designed to prevent this.

[Problem to be solved by the invention]

According to the conventional waxless polishing apparatus as described above, compared to, for example, the technique that used wax to fix the back side of the semiconductor substrate to the polishing plate, it is difficult to attach the semiconductor substrate to the polishing plate. Because it is extremely easy to attach and detach the semiconductor substrate, it is easy to flip the semiconductor substrate for double-sided polishing, and to change the attachment midway through polishing to obtain an even polishing effect. This technique is suitable for mirror polishing of substrates.

However, in the conventional waxless polishing equipment as described above, the force for fixing the semiconductor substrate to the polishing plate is
Because it depends on the negative pressure caused by the deformation of minute bubbles in the elastic porous film and the surface tension of pure water impregnated into the elastic porous film, radial movement of the semiconductor substrate is likely to occur during polishing. For this reason, as described above, conventionally, a mounting hole is formed in the template to form a minute gap with the outer periphery of the semiconductor substrate to prevent the single conductor substrate from shifting.

Additionally, if the entire back surface of the semiconductor substrate is supported by an elastic porous film, the amount of polishing at the periphery will be greater than at the center, making it impossible to obtain uniform polishing results. is made smaller than the semiconductor substrate by a predetermined value.

For this reason, minute gaps are formed on the outer periphery of the semiconductor substrate between the mounting hole of the template and the polishing plate on the back side, and abrasives and the like stay in these minute gaps. The inventors have discovered that as a result of crevice corrosion, localized surface roughness occurs on the outer periphery of a semiconductor substrate to be mirror polished.

In addition, replacement work is required due to wear and tear of the template, leading to problems such as a decrease in the operating rate of the polishing apparatus.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a polishing apparatus that can prevent surface roughening of the polished surface of the outer peripheral region of an object to be polished due to crevice corrosion or the like.

Still another object of the present invention is to provide a polishing apparatus that can improve the operating rate.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, the polishing plate according to the present invention includes a polishing surface plate, a polishing plate facing the polishing surface plate, and a circular object to be polished fixed to the surface of the polishing plate facing the polishing surface plate. This polishing device includes a template in which a mounting hole is formed, and the mounting hole formed in the template has a non-perfect circular outline.

Further, the polishing apparatus according to the present invention is a polishing apparatus comprising a polishing surface plate and a polishing plate facing the polishing surface plate, wherein the surface of the polishing plate facing the polishing surface plate has a non-perfect circular shape. A recessed portion exhibiting a shape is carved, and the object to be polished is held in this recessed portion.

Further, the polishing apparatus according to the present invention is a polishing apparatus comprising a polishing surface plate and a polishing plate facing the polishing surface plate, and the surface of the polishing plate facing the polishing surface plate is provided with a A plurality of positioning pins are protrudingly provided at desired intervals at positions surrounding the object to be polished.

[Effect]

According to the polishing apparatus of the present invention described above, the tip portion is in contact with the outer periphery of the circular object to be polished, for example, with the outline of the mounting hole formed in the template or the outline of the recess carved in the polishing plate. By providing a plurality of protrusions circumferentially arranged at desired intervals, minute gaps can be created between the outer circumference of the circular workpiece and the inner circumference of the mounting hole of the template or the recess carved in the polishing plate. This is caused by the fact that the polishing liquid does not form, and the fluidity of the polishing liquid in the area between the object to be polished and the inner periphery of the mounting hole or recess improves, and the polishing liquid remains in these minute gaps. Progression of crevice corrosion of the object to be polished is avoided, and roughening of the polished surface in the outer peripheral region of the object to be polished can be prevented.

In addition, when a plurality of pins are protruded from the position of the polishing plate surrounding the object to be polished, minute gaps are not formed around the object to be polished, and the polishing liquid around the object to be polished is prevented. This prevents the progress of crevice corrosion of the workpiece, which is caused by polishing liquid remaining in minute gaps around the workpiece, and prevents the progress of crevice corrosion in the outer peripheral area of the workpiece. It is possible to prevent the polished surface from becoming rough.

In addition, by spouting pure water, polishing liquid, etc. from multiple liquid discharge holes opened on the outer periphery of the object fixed on the polishing plate, it is ensured that the polishing liquid remains on the outer periphery of the object to be polished. As a result, the progress of crevice corrosion of the object to be polished due to retention of the polishing liquid and the like is avoided, and as a result, roughening of the polished surface in the outer peripheral region of the object to be polished can be prevented.

In addition, by carving recesses or protruding pins on the polishing plate, compared to, for example, attaching a template with mounting holes formed to the polishing plate, it is possible to replace the template due to wear and tear and stop work. etc., and can improve the operating rate and extend the life of the equipment.

[Example 1] Hereinafter, an example of a polishing apparatus which is an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view showing a part of a polishing apparatus which is an embodiment of the present invention, and FIG. 2 is a sectional view of the portion indicated by line FIG. 9 is a side view schematically showing the overall configuration.

As shown in FIG. 9 etc., the polishing apparatus of this embodiment is as follows:
The polishing plate 1 is provided with a polishing surface plate 1 in a substantially horizontal position and a polishing plate 2 arranged in a position substantially parallel to and facing the polishing plate 1.

The polishing surface plate 1 has a structure in which it is rotated at a desired speed by a motor (not shown) or the like via a drive shaft 1a provided at the center of the lower surface.

A polishing cloth 3 having a desired thickness is attached to the upper surface of the polishing surface plate 1, that is, the surface facing the polishing plate 2.

A vertical shaft 4 is connected to the central part of the polishing plate 2 facing the polishing surface plate 1 from the rear side, and this vertical shaft 4 is connected via a bearing 5 and a torquer arm 6 that is vertically movable as shown in the figure. It is supported by a non-contact casing.

The polishing plate has a structure in which it is vertically moved by the frictional force between the polishing cloth 3 and the object to be polished 11 when the surface plate 1 is driven.

Further, a pressurizing cylinder 7 is connected to one end of the vertical shaft 4 of the polishing plate 2, and is used to apply a thrust force to the vertical shaft 4 in the axial direction. An operation such as pressing the polishing plate 2 toward the polishing surface plate 1 with a pressing force of .

On the surface of the polishing plate 2 facing the polishing surface plate 1, a first
As shown in the figure, a circular template 8 is fixed by a method such as adhesive.

This template 8 includes:
A plurality of mounting holes 8a are opened at positions equally dividing the circumferential direction.

As shown in FIG. 2, a pad 1 made of an elastic porous film or the like is attached to the opposing surface of the polishing plate 2 exposed to the outside from each of the plurality of mounting holes 8a via a double-sided tape 9.
0 is attached, and with this pad 10 impregnated with pure water or the like, the back side of an object to be polished 11, such as a circular semiconductor substrate, which is mounted inside the mounting hole 8a, is removably adsorbed and fixed. It has a structure that allows

Further, as described above, the diameters of the pad 10 and double-sided tape 9 that support the object to be polished 11 from the back side are set so as to prevent excessive polishing on the outer periphery of the object to be polished 11. The diameter is made smaller by a predetermined value.

In this case, as shown in FIG. 1, on the inner circumference of the mounting hole 8a of the template 8 surrounding the object to be polished 11, there are disposed at desired intervals in the circumferential direction and have tips facing toward the center.
A plurality of protrusions 8b are formed that are substantially in contact with the outer circumference of the object to be polished 11 located in the mounting hole 8a, and the object to be polished 1
1, the structure is such that a sufficiently wide groove 8C is formed between the outer periphery of the object to be polished 11 and the inner periphery of the mounting hole 8a.

Further, a polishing agent 12 is supplied to the center of the polishing surface plate 1 from a nozzle or the like (not shown), and is dispersed to the outside of the polishing cloth 3 by the centrifugal force caused by the rotation of the polishing surface plate 1.

The operation of this embodiment will be explained below.

First, with the polishing plate 2 spaced apart from the polishing surface plate 1, the object to be polished 11 is mounted in each of the plurality of mounting holes 8a of the template 8 fixed to the polishing plate 2.

T Rumor 1 At this time, the outer circumference of the object to be polished 11 is guided by the plurality of protrusions 8b of the mounting hole 8a, so that the object to be polished 11
is positioned at the center of the mounting hole 8a, and is stably fixed to the polishing plate 2 by being attracted to the pad 10 on the back side.

Thereafter, by operating the pressure cylinder 7 or the like, the polishing plate 2 is lowered toward the polishing surface plate 1, and the object to be polished 11 is placed in a predetermined position against the polishing cloth 3 stretched on the rotating polishing surface plate 1. The polishing agent 12 is supplied while the workpiece 11 to be polished is pressed between the polishing plate 2 and the polishing surface plate 1 so that the polishing plate 2 and the polishing surface plate 1 slide with a pressure of .

By continuing this state for a predetermined period of time, the main surface of the object to be polished 11 in contact with the polishing cloth 3 is mirror-polished, and the radial direction of the object to be polished 11 due to the frictional force with the polishing cloth 3 during polishing is Misalignment is prevented by the plurality of protrusions 8b that come into contact with the outer circumference of the object to be polished 11.

Here, in the conventional case, for example, as shown in FIG. 11, as mentioned above,
During polishing, a fine gap 800 is formed over almost the entire circumference between the outer circumference of the object to be polished 11 and the inner circumference of the mounting hole 800a.
C is formed.

For this reason, there is a problem in that the abrasive 12 and the like supplied during polishing remain in the minute gaps 800c and cause crevice corrosion to the object 11 to be polished.

However, in the case of this embodiment, the object to be polished 11
Since the structure provides support in the radial direction, a sufficiently wide groove 8C is formed in the portion other than the protrusion 8b, as shown in FIG.

For this reason, the abrasive 1 on the outer periphery of the object 11 to be polished, etc.
2 does not remain, and the abrasive 12 flows through this wide groove 8c, so that the abrasive 12 is allowed to flow into the fine gap partially formed between the tip of the protrusion 8b and the outer periphery of the object 11 to be polished. is prevented from remaining.

As a result, the attachment hole 8a of the object to be polished 11 and the template 8
Crevice corrosion caused by the abrasive 12 etc. in the area between
Surface roughening due to corrosion is reliably prevented from occurring in the surrounding areas.

In addition, the outer periphery of the object to be polished 11 and the mounting hole 8 of the template 8
By inserting a desired tool etc. into the wide groove 8C between a, it becomes possible to remove the workpiece 11 from the polishing plate 2 extremely easily without causing damage to the workpiece 11. As a result, the time required for attaching and detaching the object to be polished 11 is shortened, and as a result, the operating rate of the polishing apparatus is improved.

[Example 2]! 31! 1 is a plan view showing an example of a main part of a polishing apparatus according to another embodiment of the present invention, and FIG. 4 is a sectional view of a portion indicated by line IV-rV in FIG. 3.

In the case of the second embodiment, the object to be polished 11 is accommodated on the surface of the polishing plate 20 made of ceramics, stainless steel, etc., facing the polishing surface plate 1, and has an inner diameter sufficiently larger than that of the object to be polished 11. multiple recesses 20a
The structure is engraved with.

Further, as shown in FIG. 3, on the inner periphery of this recess 20a, the object to be polished 11 is arranged at desired intervals in the circumferential direction, and has a tip facing toward the center of the workpiece 11 located within the recess 2Oa. A plurality of protrusions 20b are formed that are substantially in contact with the outer periphery,
When the object to be polished 11 is attached, the tips of the plurality of protrusions 20b prevent the object to be polished from shifting in the radial direction, and the distance between the outer periphery of the object to be polished 11 and the inner periphery of the recess @B20a is prevented. The structure is such that a sufficiently wide groove 20c is formed in the groove 20c.

Therefore, in the case of the second embodiment, the wide groove 20C existing on the outer periphery of the object to be polished 11 provides the same effect as in the first embodiment, and the recess for holding the object to be polished 11 20a is integrally carved into the polishing plate 20, it is possible to obtain sufficient strength for the plurality of protrusions 2Qb formed on the inner circumference of the recess 20a, and to avoid the trouble of replacing worn templates. This eliminates the need for extensive maintenance work, making it possible to improve the operating rate of the polishing equipment and extend its service life.

[Embodiment 3] FIG. 5 is a plan view showing an example of a main part of a polishing apparatus which is another embodiment of the present invention, and FIG.
It is a sectional view of the part shown by tvt.

In the case of this embodiment 3, the polishing surface plate 1 of the polishing plate 21 is
It has a structure in which a plurality of positioning pins 21a are arranged at predetermined intervals on the opposing surface so as to surround each of the plurality of objects to be polished 11 mounted on the opposing surface.

The object to be polished 11 is attached to the plurality of positioning pins 21a.
By abutting the outer periphery of the polishing member, it is possible to prevent radial displacement of the object to be polished 11 during polishing, and also to position the object to be polished 11 when it is mounted.

With such a structure of the polishing plate 21, the outer peripheral part of the object to be polished 11 mounted on the polishing plate 21 is coated with the polishing agent 1.
There are no minute gaps where 2 can stay, and
The flow state of the abrasive 12 around the object to be polished 11 is also good, and the positioning pin 21a supported by the polishing plate 21 has sufficient strength, so that Example 1
And the same effects as in Example 2 can be obtained.

[Embodiment 4] FIG. 7 is a plan view showing an example of the essential parts of a polishing apparatus which is another embodiment of the present invention, and FIG.
It is a cross-sectional view of the part indicated by −■.

In the case of the fourth embodiment, a plurality of mounting holes 80a having an inner diameter slightly larger than the outer diameter of the object to be polished 11 are formed in the template 80 fixed to the polishing plate 22, and each of the mounting holes 80a is The object to be polished 11 is attached to the holder.

In addition, in FIG. 7, the polishing plate 22 is shown without the object 11 to be polished, in order to make the main parts easier to see.

In this case, in the polishing plate 22, the object 1 to be polished is
1, that is, the polishing plate 22,
A plurality of liquid jetting holes 22a are provided in a region where a fine gap is formed between the inner periphery of the mounting hole 80a and the object to be polished 11, and pure water 13 or polishing water is supplied to the region from the outside at any time. By supplying the polishing agent 12 and the like, the polishing agent 12 is prevented from staying in a region where a fine gap is formed between the inner periphery of the mounting hole 80a and the object to be polished 11.

As a result, crevice corrosion caused by retention of the abrasive 12 on the outer periphery of the object 11 to be polished is reliably avoided, and a good polishing result with no roughness on the polished surface of the outer periphery of the mirror-polished object 11 is achieved. can be obtained.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the above and Examples, and it is possible to make various changes without departing from the gist of the invention. Not even.

For example, the mounting hole of the template for holding the object to be polished, the shape of the recess carved in the polishing plate, and the configuration of the polishing apparatus are not limited to those exemplified in each of the above-described embodiments.

Further, the object to be polished is not limited to semiconductor substrates, but can be widely applied to similar objects to be polished.

〔Effect of the invention〕

Among the inventions disclosed in this application, the effects obtained by typical inventions are briefly described below.

That is, according to the polishing apparatus according to claim 1 of the present invention, there is provided a polishing surface plate, a polishing plate facing the polishing surface plate, and a circular shape fixed to the surface of the polishing plate facing the polishing surface plate. The polishing apparatus includes a template in which a mounting hole is formed into which an object to be polished is mounted, and the mounting hole formed in the template has a non-perfect circular outline. For example, by making the contour of the formed mounting hole have a plurality of protrusions arranged in the circumferential direction at desired intervals so that the tip part is in contact with the outer periphery of the circular object to be polished, a circular shape can be formed. This eliminates the formation of minute gaps between the outer periphery of the object to be polished and the inner periphery of the recess carved in the mounting hole of the template, and also reduces the gap between the object to be polished and the inner periphery of the mounting hole or recess. The fluidity of the polishing liquid in the area becomes better, and the progress of crevice corrosion of the object to be polished, which is caused by the retention of the polishing liquid in these minute gaps, is avoided. Roughness can be prevented.

Further, according to the polishing device of the present invention, the polishing device includes a polishing surface plate and a polishing plate facing the polishing surface plate, wherein a surface of the polishing plate facing the polishing surface plate has a contour. Since the structure is such that a concave portion having a non-perfect circular shape is carved and the object to be polished is held in this concave portion, the outline of the concave portion carved in the polishing plate is, for example,
By having a plurality of protrusions arranged circumferentially at desired intervals so that the tip contacts the outer periphery of the circular object to be polished, the polishing plate is engraved on the outer periphery of the circular object to be polished. This eliminates the formation of minute gaps between the inner periphery of the recess and improves the fluidity of the polishing liquid in the region between the workpiece and the mounting hole or the inner periphery of the recess. Progression of crevice corrosion of the object to be polished due to retention of polishing liquid or the like in the gaps is avoided, and roughening of the polished surface in the outer peripheral region of the object to be polished can be prevented.

Furthermore, by carving recesses in the polishing plate, compared to, for example, attaching a template with mounting holes formed to the polishing plate, there is no need to replace the template due to wear and tear or stop work, and the equipment can be operated. It is possible to improve the efficiency and extend the lifespan.

Further, according to the polishing apparatus of the present invention, the polishing apparatus includes a polishing surface plate and a polishing plate facing the polishing surface plate, and the surface of the polishing plate facing the polishing surface plate has the Since it has a structure in which a plurality of positioning pins are protruded at desired intervals at positions surrounding the object to be polished that is attached to the opposing surface, there is no concern that minute gaps will be formed around the object to be polished. , the flow of the polishing liquid around the workpiece is not obstructed, and the polishing liquid remains in the minute gaps around the workpiece, resulting in the progress of crevice corrosion of the workpiece. This makes it possible to prevent roughness of the polished surface in the outer peripheral region of the object to be polished.

In addition, since the polishing plate has a structure in which a plurality of liquid spouting ports for spouting abrasive or pure water are opened at positions facing the outer periphery of the object to be polished attached to the polishing plate, the polishing plate Occurrence of crevice corrosion due to retention of abrasive and the like in the peripheral area of the fixed object to be polished 11 is reliably prevented, and roughening of the polished surface in the outer peripheral region of the object to be polished can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a part of a polishing apparatus which is an embodiment of the present invention, FIG. 2 is a cross-sectional view of the portion indicated by line ■-■ in FIG. 1, and FIG. FIG. 4 is a sectional view of the portion indicated by line 1'V-■ in FIG. 3; FIG. FIG. 6 is a sectional view of the portion indicated by line VT-Vl in FIG. FIG. 8 is a sectional view of the part indicated by the line ■-■ in FIG. The 1O diagram is
FIG. 2 is a plan view showing an example of a main part of a conventional polishing apparatus. DESCRIPTION OF SYMBOLS 1... Polishing surface plate, la... Drive shaft, 2... Polishing plate, 3... Polishing cloth, 4... Drive shaft, 5...
・Bearing, 6... Torque arm, 7... Pressure cylinder, 8... Template, 8a... Mounting hole, 8b...
・Protrusion, 8c...Wide groove, 9...Double-sided tape, I
O... Pad, 11... Object to be polished, 12... Polishing agent, 13... Pure water, 20... Polishing plate, 20a
... recess, 20b... protrusion, 20c... wide groove,
21... Polishing plate, 21a... Positioning pin,
22... Polishing plate, 22a... Liquid jet hole, 80
... Template, 80a... Mounting hole, 800...
・Template, 800a... Mounting hole, 800c...
·gap. Fig. 1 1o.../Mando 3 Fig. Fig. Q Fig. Fig. 2] 0... place 1 dog Jh Bee/ Fig.

Claims (1)

[Claims] 1. A polishing surface plate, a polishing plate facing the polishing surface plate, and a mounting hole fixed to the surface of the polishing plate facing the polishing surface plate, into which a circular object to be polished is mounted. What is claimed is: 1. A polishing device comprising a template in which a template is formed, wherein the mounting hole formed in the template has a non-perfect circular outline. 2. A polishing device comprising a polishing surface plate and a polishing plate facing the polishing surface plate, wherein a recessed portion having a non-perfect circular outline is carved on the surface of the polishing plate facing the polishing surface plate. and the object to be polished is held in this recess. 3. A polishing device comprising a polishing surface plate and a polishing plate facing the polishing surface plate, wherein the surface of the polishing plate facing the polishing surface plate has the object to be polished mounted on the opposite surface. A polishing device comprising a plurality of positioning pins protruding at desired intervals at positions surrounding the polishing device. 4. The outline of the mounting hole or the outline of the recess of the template consists of a plurality of protrusions arranged in the circumferential direction at desired intervals so that the tip portions are substantially in contact with the outer periphery of the circular object to be polished. The polishing apparatus according to claim 1 or 2, characterized in that: 5. Claim 1, wherein the polishing plate is provided with a plurality of liquid spouting ports for spouting abrasive or pure water at positions facing the outer periphery of the object to be polished.
4. The polishing device according to 2, 3 or 4.