KR20210026436A - Reusable retainer-ring for polishing wafer and manufacturing method thereof - Google Patents

Abstract

According to one embodiment of the present invention, a reusable retainer ring for polishing a wafer comprises: a processing ring having a metallic insert ring which has a circular ring shape and has pin holes at a predetermined interval in a circumference direction and having a first polishing ring partially surrounding the insert ring; and a second polishing ring injection-molded while surrounding the processing ring.

Description

Reusable retainer ring for wafer polishing and its manufacturing method {REUSABLE RETAINER-RING FOR POLISHING WAFER AND MANUFACTURING METHOD THEREOF}

The present invention relates to a retainer ring and a manufacturing method thereof, and more particularly, to a retainer ring for wafer polishing that can be reused in a chemical mechanical polishing (CMP) process, and a manufacturing method thereof.

In the manufacturing process of a semiconductor device, a polishing process for flattening the surface of a semiconductor wafer is essentially included.

The chemical mechanical polishing (CMP) process is mainly used in this polishing process. The CMP process is a method of polishing the surface of a wafer coated with tungsten or oxide using mechanical friction and at the same time polishing using a chemical polishing agent.

In the CMP process, the wafer fixed to the carrier is rotated while being pressed against the polishing pad, so that the wafer surface is polished by friction between the polishing pad and the wafer surface.

Further, the surface of the wafer is chemically polished by the slurry (chemical polishing agent) supplied between the polishing pad and the wafer. During this process, the retainer ring supporting the wafer wears out along with the wafer, so it must be replaced at the end of its service life.

However, since the retainer ring is made of a highly functional resin having abrasion resistance and its price is high, there is a problem that the manufacturing cost due to replacement increases. Various methods are being sought to solve this problem.

The present invention has been proposed in view of the above circumstances, and an object of the present invention is to provide a retainer ring for wafer polishing that can be reused in a chemical mechanical polishing (CMP) process and a method of manufacturing the same.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

Reusable wafer polishing retainer ring according to an embodiment of the present invention comprises an insert ring made of a metal material in which pinholes are formed at predetermined intervals along a circumferential direction, forming a circular ring shape, and partially enclosing the insert ring. A processing ring having a first polishing ring; And a second polishing ring formed by injection molding while surrounding the processing ring.

The processing ring is cut to a predetermined size in an injection-molded state, and then double-injection-molded while being wrapped in the second abrasive ring.

It is preferable that a portion of the insert ring that is not wrapped by the first polishing ring is wrapped by the second polishing ring.

The insert ring has a first inclined surface on the upper side of the inner circumferential surface and inclined in a form that the diameter becomes narrower from the top to the bottom.

The insert ring has a second inclined surface on the lower side of the outer circumferential surface and inclined in a form of narrowing in diameter from top to bottom.

The insert ring has a first inclined surface that is inclined at an upper side of an inner circumferential surface in a form that decreases in diameter from top to bottom, and a first vertical surface formed perpendicular to a lower side of the inner circumferential surface of the insert ring, and the first polishing ring It is preferable that the first inclined surface is enclosed, and the inner circumferential surface of the first polishing ring is formed vertically so as to contact the first vertical surface.

The insert ring has a second inclined surface that is inclined at a lower side of the outer circumferential surface in a form that decreases in diameter from top to bottom, and a second vertical surface formed perpendicular to the upper side of the inner circumferential surface of the insert ring, and the first polishing ring It is preferable to surround the outer peripheral surface of the insert ring in a shape corresponding to the shape of the second inclined surface and the second vertical surface.

In this case, it is preferable that the second polishing ring does not cover a portion of the first polishing ring surrounding the second inclined surface.

It is preferable that the insert ring is made of a zinc (Zn) material.

The first and second abrasive rings are made of a polyether ether ketone (PEEK) material.

The first and second polishing rings may be made of any one of polyether ether ketone (PEEK), polyoxymethylene (POM), and polyphenylene sulfide (PPS). .

The first and second abrasive rings fill a portion of the insert ring in which a pin hole is formed, and an engaging groove is provided for each portion of the pin hole.

The coupling groove is formed with a thread on the inner circumferential surface.

A hollow female screw having a threaded shape may be provided on the inner circumferential surface of the coupling groove.

The second polishing ring has a plurality of slurry discharge passages having a groove shape formed in a diagonal line at the bottom thereof.

Reusable wafer polishing retainer ring according to another embodiment of the present invention includes an insert ring made of a metal material forming a circular ring shape; A first abrasive ring partially surrounding the insert ring; And a second abrasive ring formed by injection molding while enclosing the insert ring and the first abrasive ring, wherein the insert ring and the first abrasive ring are cut to a preset size in an injection-molded state, and then the second It is formed by double injection molding while wrapped in a polishing ring.

In this case, the insert ring has pinholes formed at predetermined intervals along the circumferential direction.

On the other hand, the method for manufacturing a retainer ring for wafer polishing that can be reused according to an embodiment of the present invention includes an injection-molded retainer ring including an insert ring made of a metal material and a polishing ring surrounding the insert ring, to a predetermined size. A first cutting step of cutting and processing into a recyclable processing ring; A molding step of seating the processing ring and then injection molding to generate a second polishing ring around the processing ring; And a second cutting step of cutting the second polishing ring to a predetermined size.

In the first cutting step, the polishing ring is cut into a rectangular shape so that the insert ring is not cut and processed into a first polishing ring.

A method for manufacturing a retainer ring for wafer polishing that can be reused according to another embodiment of the present invention includes an injection-molded retainer ring including an insert ring made of a metal material and a polishing ring surrounding the insert ring, and cut to a preset size. And a cutting step of processing into a recyclable processing ring, and a molding step of seating the processing ring and then injection molding to generate a second polishing ring around the processing ring.

The present invention can provide a retainer ring for wafer polishing that can be reused by cutting an injection product already used in a chemical mechanical polishing (CMP) process, adding a synthetic resin, and then double injection to provide a method of manufacturing the same.

Accordingly, it is possible to recycle the retainer ring for wafer polishing that has already been used, thereby reducing the cost and producing the retainer ring of the same quality as a new product.

1 is a front perspective view schematically showing a retainer ring for wafer polishing according to an embodiment of the present invention.
Figure 2 is a rear perspective view schematically showing a retainer ring for wafer polishing according to an embodiment of the present invention.
3 is a plan view schematically showing a retainer ring for wafer polishing according to an embodiment of the present invention.
Figure 4 is a view showing a cross-section AA' shown in Figure 3;
5 is a flow chart showing a method of manufacturing a retainer ring for wafer polishing according to an embodiment of the present invention.
6 is a view illustrating a method of manufacturing a retainer ring for wafer polishing according to an embodiment of the present invention.
7 is a flow chart showing a method of manufacturing a retainer ring for wafer polishing according to another embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms different from each other, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to fully inform the scope of the invention to those who have it, and the invention is defined by the description of the claims. Meanwhile, terms used in the present specification are for explaining embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used herein, "comprises" or "comprising" refers to the presence of one or more other components, steps, actions and/or elements other than the recited elements, steps, actions and/or elements, or Does not exclude addition.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a front perspective view schematically showing a retainer ring for wafer polishing according to an embodiment of the present invention, and FIG. 2 is a rear perspective view schematically showing a retainer ring for wafer polishing according to an embodiment of the present invention.

In manufacturing a semiconductor device, one of the problems that must be solved in a multi-layer connection process required to realize a reduction in device size due to an increase in integration degree and thus to implement a complex function integrated circuit is a planarization process.

Planarization is necessary not only for the dielectric to be deposited, but also for various conductors. If the planarization process is not performed, a precise pattern cannot be obtained in the exposure process, and the step coverage of the conductor and dielectric deposition film is poor, which can lead to operation defects.

CMP technology is often used when it is necessary to planarize the entire wafer at once because the pad has the advantage of being able to cover a large surface area in most cases.

Referring to FIGS. 1 and 2 in parallel, the retainer ring 100 for wafer polishing is formed in a form in which an insert ring made of a metal material (not shown) and a second polishing ring 300 surrounding the insert ring are combined. .

The second polishing ring 300 is made of a polyether ether ketone (PEEK) material, and has a function of protecting the inner insert ring.

The second polishing ring 300 has a structure coupled to a polishing apparatus (not shown) provided for polishing a wafer. At this time, the second polishing ring 300 is provided with a coupling groove 310 formed at a predetermined interval along the circumferential direction.

Here, the predetermined interval is an interval indicating a position to be coupled to the polishing apparatus, and may vary depending on the joint portion and position.

The coupling groove 310 has a thread formed on the inner circumferential surface to be coupled to the polishing apparatus. For stronger coupling force, a hollow female screw (not shown) in which a thread is formed may be provided on the inner circumferential surface of the coupling groove 310.

A slurry discharge path 320 is formed on the rear surface of the second polishing ring 300 at predetermined intervals along the circumferential direction. The slurry discharge path 320 has a groove shape formed in an oblique line. The slurry discharge path 320 guides the slurry, which is a chemical polishing agent, supplied between the polishing pad (not shown) and the wafer to the outside.

3 is a plan view schematically showing a retainer ring for wafer polishing according to an embodiment of the present invention, and FIG. 4 is a view showing a cross section taken along line A-A' shown in FIG. 3.

Referring to FIGS. 3 and 4 in parallel, the retainer ring 100 for wafer polishing includes a processing ring 200 and a second polishing ring 300.

The processing ring 200 is formed by processing a retainer ring that has been used at least once after injection molding, and includes an insert ring 210 and a first polishing ring 220.

The insert ring 210 forms a circular ring shape. The insert ring 210 is a frame ring that maintains the shape of the retainer ring 100 for wafer polishing, and is preferably made of a metal material. At this time, the insert ring 210 is made of a zinc (Zn) material.

The insert ring 210 is formed with pin holes (not shown) at predetermined intervals along the circumferential direction. The pin hole is filled by injection-molded first and second polishing rings 220 and 300. Accordingly, a coupling groove (310 of FIG. 1) described in FIGS. 1 to 2 is provided for each portion in which the pin hole is formed.

The insert ring 210 includes first and second inclined surfaces 211 and 212 and first and second vertical surfaces 213 and 214.

The first inclined surface 211 is a section inclined in a form in which the diameter decreases from the top to the bottom on the upper side of the inner circumferential surface of the insert ring 210.

The second inclined surface 212 is a section inclined at a lower side of the outer circumferential surface of the insert ring 210 in a form in which the diameter decreases from top to bottom.

The first vertical surface 213 is a section vertically formed below the inner circumferential surface of the insert ring 210 and is connected to the lower end of the first inclined surface 211.

The second vertical surface 214 is a section vertically formed above the outer peripheral surface of the insert ring 210 and is connected to the upper end of the second inclined surface 212.

The upper surface of the insert ring 210 is formed between the upper end of the first inclined surface 211 and the upper end of the second vertical surface 214.

The lower surface of the insert ring 210 is formed between the lower end of the first vertical surface 213 and the lower end of the second inclined surface 212.

The first polishing ring 220 partially surrounds the insert ring 210. Here, the first polishing ring 220 is preferably made of a polyether ether ketone (PEEK) material.

At this time, the first polishing ring 220 is made of any one of polyether ether ketone (PEEK), polyoxymethylene (POM), and polyphenylene sulfide (PPS). It can be done.

The first polishing ring 220 surrounds the first inclined surface 211, and the inner circumferential surface of the first polishing ring 220 is vertically formed to contact the first vertical surface 213.

In this case, it is preferable that an angle (a) between the outer surface of the first polishing ring 220 and the first inclined surface 211 in contact with the first vertical surface 213 is an acute angle.

That is, since the insert ring 210 is made of a metal material to maintain its shape, the inclined inner circumferential surface of the second polishing ring 300 to be polished in the polishing process must be effectively maintained. For this, it is preferable that the angle (a) between the outer surface of the first polishing ring 220 and the first inclined surface 211 is an acute angle.

The first polishing ring 220 surrounds the outer peripheral surface of the insert ring 210 in a shape corresponding to the shape of the second inclined surface 212 and the second vertical surface 214.

The second polishing ring 300 is formed by injection molding while enclosing the processing ring 200. At this time, the processing ring 200 is cut to a predetermined size in the injection-molded state and then double-injection-molded while being wrapped in the second polishing ring 300.

The preset size is a size required in a processing environment during injection, and in the present invention, it means cutting the polishing ring in a rectangular shape so that the insert ring of the retainer ring that has already been used is not cut.

Accordingly, the retainer ring is machined into the machining ring 200, and the polishing ring is cut into the first abrasive ring 220.

The second polishing ring 300 may be made of any one of polyether ether ketone (PEEK), polyoxymethylene (POM), and polyphenylene sulfide (PPS). have.

In this case, the second polishing ring 300 is preferably made of the same material as the first polishing ring 220. This is because, when double injection, the mutually bonded grip is improved and there is no change in physical properties, so it is easy to form a single material even during double injection.

The second polishing ring 300 does not surround a portion of the first polishing ring 220 surrounding the second inclined surface 212. This is because the first polishing ring 220 can fully function as a polishing material in the first place. It is also helpful in terms of cost reduction.

The second polishing ring 300 surrounds and protects a portion of the insert ring 210 that is not wrapped by the first polishing ring 220.

5 is a flowchart illustrating a method of manufacturing a retainer ring for wafer polishing according to an exemplary embodiment of the present invention, and FIG. 6 is a view illustrating a method of manufacturing a retainer ring for wafer polishing according to an exemplary embodiment of the present invention.

5 and 6, a method of manufacturing a retainer ring for wafer polishing largely includes a first cutting step (S100), a forming step (S200), and a second cutting step (S300).

At this time, the three steps (S100, S200, S300) will be described step by step with reference to FIG. 6.

Referring to FIG. 6, the horizontal length (L1, L2, L3, L4, L5) and the vertical width (w1, w2, w3, w4, w5) are shown, and these figures are only one example for explaining the present invention. Therefore, it is not limited to that number. However, the range of the ratio according to the corresponding value may be meaningful.

6A shows the retainer ring 10 as a finished product. This retainer ring 10 includes an insert ring 11 and an abrasive ring 12. At this time, the horizontal length L1 of the finished product retainer ring 10 is 29.67mm, and the vertical width w1 is 19.15mm.

6B shows a form in which the retainer ring 10 is used more than once in the polishing process so that the horizontal length L2 is the same as L1 and only the vertical widths w2 and 18mm are reduced. As described above, the retainer ring 10 used in the polishing process is rotated while being pressed against a polishing pad (not shown). The retainer ring 10 is worn together with the wafer by the frictional force and rotational force.

Since such retainer ring 10 is a consumable item in the CMP process, it is discarded when its life is over. That is, the retainer ring 10, which has reached the end of its service life due to the progress of wear, is difficult to use any more because its dimensions and shapes are different. Accordingly, the replacement cycle of the retainer ring 10 is shortened, and the process cost of the CMP process is inevitably increased.

6C shows a first cutting step (S100) in the method of manufacturing a retainer ring for wafer polishing that can be reused according to the present invention.

The first cutting step (S100) is a step of cutting the retainer ring 10, which is difficult to use again due to different dimensions and shapes, to a preset size, thereby making a processing ring 200 that can be recycled.

In other words, in the first cutting step (S100), an injection-molded retainer ring 10 including an insert ring 11 made of a metal material and a polishing ring 12 surrounding the insert ring 11 is set in advance. It is a step of cutting to size and processing it into a processing ring 200 that can be recycled.

At this time, the horizontal length (L3) of the processing ring 200 is 22.6mm, and the vertical width (w3) is 13.8mm.

In the first cutting step (S100), the polishing ring (12 of b) is cut into a rectangular shape so that the insert ring (11 of b) is not cut and processed into the first polishing ring 220.

This not only simplifies the process, but also can significantly reduce the waste of expensive synthetic resin materials.

6D shows a forming step (S200) in the method of manufacturing a retainer ring for wafer polishing that can be reused according to the present invention.

In the molding step (S200), after the processing ring 200 is seated, injection molding is performed to generate a second polishing ring 300 around the processing ring 200.

At this time, the horizontal length L4 of the reusable wafer polishing retainer ring 100 is 33.3mm, and the vertical width w4 is 23.3mm.

6(e) shows a second cutting step (S300) in the method for manufacturing a retainer ring for wafer polishing that can be reused according to the present invention.

In the second cutting step S300, the second polishing ring 300 is cut to a predetermined size. At this time, the horizontal length L4 of the reusable wafer polishing retainer ring 100 is 29.67mm, and the vertical width w5 is 19.15mm.

7 is a flowchart illustrating a method of manufacturing a retainer ring for wafer polishing according to another embodiment of the present invention.

Referring to FIG. 7, a method of manufacturing a retainer ring for wafer polishing according to another embodiment of the present invention includes a cutting step S100 and a forming step S200.

In the cutting step (S100), an injection-molded retainer ring including an insert ring made of a metal material and a polishing ring surrounding the insert ring is cut to a preset size and processed into a recyclable processing ring.

In the molding step (S200), after the processing ring is seated, injection molding is performed to generate a second polishing ring around the processing ring.

At this time, the basic mold used in the molding step (S200) is installed in a preset size, and in the molding step (S200), a retainer ring can be produced without a separate cutting process.

Other overlapping descriptions have been described through the previous drawings, and thus will be omitted.

As described above, the present invention can provide a retainer ring for wafer polishing that can be reused by cutting an injection product already used in a chemical mechanical polishing (CMP) process, adding a synthetic resin, and then double injection to provide a method for manufacturing the same. .

Accordingly, it is possible to recycle the previously used retainer ring for wafer polishing, thereby reducing the cost and producing a retainer ring of the same quality as a new product.

The present invention is not limited to the above-described embodiments, and can be implemented with various modifications within the scope of the technical idea of the present invention.

10: retainer ring 11: insert ring
12: polishing ring
100: Reusable wafer polishing retainer ring
200: machining ring 210: insert ring
211: first slope 212: second slope
213: first vertical surface 214: second vertical surface
220: first polishing ring 300: second polishing ring
310: coupling groove 320: slurry discharge path

Claims (21)

A processing ring having a metal insert ring having a circular ring shape and having pinholes formed at predetermined intervals along the circumferential direction, and a first polishing ring partially surrounding the insert ring; And
Reusable wafer polishing retainer ring comprising; a second polishing ring formed by injection molding while enclosing the processing ring.
The method of claim 1,
The processing ring is
Reusable wafer polishing retainer ring that is cut to a predetermined size in an injection-molded state and then double-injection-molded while being wrapped in the second polishing ring.
The method of claim 1,
The insert ring is
Reusable wafer polishing retainer ring, wherein a portion not wrapped by the first polishing ring is wrapped by the second polishing ring.
The method of claim 1,
The insert ring is
Reusable wafer polishing retainer ring having a first inclined surface on the upper side of the inner circumferential surface and inclined in a form of narrowing in diameter from top to bottom.
The method of claim 1,
The insert ring is
Reusable wafer polishing retainer ring having a second inclined surface that is inclined at a lower side of the outer circumferential surface in a form of narrowing in diameter from top to bottom.
The method of claim 1,
The insert ring is
It has a first inclined surface that is inclined in a form that the diameter becomes narrower from the top to the bottom on the upper side of the inner circumferential surface, and a first vertical surface formed perpendicular to the lower side of the inner circumferential surface of the insert ring,
The first polishing ring
Reusable wafer polishing retainer ring surrounding the first inclined surface, wherein the inner circumferential surface of the first polishing ring is formed vertically so as to contact the first vertical surface.
The method of claim 1,
The insert ring is
It has a second inclined surface that is inclined in a form that the diameter becomes narrower from the top to the bottom on the lower side of the outer circumferential surface, and a second vertical surface formed perpendicular to the upper side of the inner circumferential surface of the insert ring,
The first polishing ring
Reusable wafer polishing retainer ring that surrounds the outer peripheral surface of the insert ring in a shape corresponding to the shape of the second inclined surface and the second vertical surface.
The method of claim 1,
The insert ring is
It has a second inclined surface that is inclined in a form that the diameter becomes narrower from the top to the bottom on the lower side of the outer circumferential surface, and a second vertical surface formed perpendicular to the upper side of the inner circumferential surface of the insert ring,
The first polishing ring
Enclosing the outer circumferential surface of the insert ring in a shape corresponding to the shape of the second inclined surface and the second vertical surface,
The second polishing ring
Reusable wafer polishing retainer ring that does not surround the portion of the first polishing ring surrounding the second inclined surface.
The method of claim 1,
The insert ring is
Reusable wafer polishing retainer ring made of zinc (Zn) material.
The method of claim 1,
The first and second polishing rings
Reusable wafer polishing retainer ring made of polyether ether ketone (PEEK) material.
The method of claim 1,
The first polishing ring
Reusable wafer polishing retainer ring made of any one of polyether ether ketone (PEEK), polyoxy methylene (POM), and polyphenylene sulfide (PPS) .
The method of claim 1,
The second polishing ring
Reusable wafer polishing retainer ring made of any one of polyether ether ketone (PEEK), polyoxy methylene (POM), and polyphenylene sulfide (PPS) .
The method of claim 1,
The first and second polishing rings
Filling the portion where the pin hole of the insert ring is formed,
Reusable wafer polishing retainer ring that is provided with a coupling groove for each portion of the pin hole is formed.
The method of claim 13,
The coupling groove is
Reusable wafer polishing retainer ring in which threads are formed on the inner circumferential surface.
The method of claim 13,
On the inner circumferential surface of the coupling groove
Reusable wafer polishing retainer ring that is provided with a hollow female screw threaded.
The method of claim 1,
The second polishing ring
Reusable wafer polishing retainer ring provided with a plurality of slurry discharge paths having a groove shape formed in a diagonal line at the bottom.
Insert ring made of metal forming a circular ring shape;
A first abrasive ring partially surrounding the insert ring; And
Includes; a second abrasive ring formed by injection molding in a state surrounding the insert ring and the first abrasive ring,
The insert ring and the first abrasive ring
Reusable wafer polishing retainer ring that is cut to a predetermined size in an injection-molded state and then double-injection-molded while being wrapped in the second polishing ring.
The method of claim 17,
The insert ring is
Reusable wafer polishing retainer ring having pinholes formed at predetermined intervals along the circumferential direction.
A first cutting step of cutting an injection-molded retainer ring including an insert ring made of a metal material and a polishing ring surrounding the insert ring to a preset size and processing it into a recyclable machining ring;
A molding step of seating the processing ring and then injection molding to generate a second polishing ring around the processing ring; And
Reusable wafer polishing retainer ring manufacturing method comprising; a second cutting step of cutting the second polishing ring to a predetermined size.
The method of claim 19,
The first cutting step
A method of manufacturing a retainer ring for wafer polishing that can be reused by cutting the polishing ring into a first polishing ring by cutting the polishing ring in a rectangular shape so that the insert ring is not cut.
A cutting step of cutting an injection-molded retainer ring including an insert ring made of a metal material and a polishing ring surrounding the insert ring to a preset size and processing it into a recyclable processing ring,
A method of manufacturing a retainer ring for reusable wafer polishing comprising a molding step of seating the processing ring and then injection molding to generate a second polishing ring around the processing ring.

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