CN115555988A

CN115555988A - Retaining ring for CMP grinding

Info

Publication number: CN115555988A
Application number: CN202211375040.5A
Authority: CN
Inventors: 刘健; 王俊
Original assignee: Jingzhou Huanxiang Special Materials Co ltd
Current assignee: Jingzhou Huanxiang Special Materials Co ltd
Priority date: 2022-11-04
Filing date: 2022-11-04
Publication date: 2023-01-03

Abstract

The invention discloses a retaining ring for CMP grinding, which comprises a metal ring and a wear resin ring, wherein the metal ring and the wear resin ring are connected by adopting a dovetail groove type structure.

Description

Retaining ring for CMP grinding

The technical field is as follows:

the present invention relates to a retainer ring of a chemical mechanical polishing apparatus, and more particularly, to a retainer ring for CMP polishing.

The background art comprises the following steps:

in a semiconductor wafer manufacturing process, a surface planarization operation is performed on a semiconductor wafer by a Chemical Mechanical Polishing (CMP) apparatus.

The chemical mechanical polishing apparatus is an oxide film coated on a semiconductor wafer using chemical and physical actions. Which is a device for flattening or removing a metal film by grinding.

In the related art, as shown in fig. 1, a chemical mechanical polishing apparatus has a lower wafer receiving portion for receiving a semiconductor wafer 7, a polishing head 5 formed on a surface, connected to a motor to rotate, disposed below the polishing head 5, a polishing pad 6 for polishing the surface of the semiconductor wafer 7 received in the polishing head 5, and a chemical polishing agent applied on the polishing pad 6, the polishing head 5 being equipped with a retainer ring which forms a wafer receiving portion on the lower surface. The outer peripheral surface of the semiconductor wafer 7 is caught by the inner peripheral surface of the retainer ring during the chemical mechanical polishing operation of the receiving portion of the polishing head 5 and is not detached. The slurry as a chemical polishing agent supplied from the polishing agent supply unit to the polishing pad is supplied into the semiconductor housing portion through the polishing agent supply groove in contact with the ring body 1b, and oxidizes the surface of the semiconductor wafer. The chemical mechanical polishing apparatus rotates the polishing head and the polishing pad by chemical oxidation of the slurry. Repeating the polishing operation of polishing the surface of the semiconductor wafer in contact with the polishing pad while repeating the polishing operation of polishing the surface of the semiconductor wafer uniformly; the main design of the prior art CMP retaining ring is divided into an adhesive type and an integral coating type, in fig. 1, the adhesive type is that a metal ring 1a and a worn resin layer 1b are bonded by using an adhesive, the CMP ring rotates or moves in the wearing process, the metal ring 1b is influenced by a shearing force, and when the pressure or the speed is too high, the shearing force is increased, and the bonded interface has a risk of separation;

the adhesive simultaneously has a risk of poor curing or leakage, the leaked bonding material is hardened and separated during the polishing operation, and the wafer surface is soiled, and also because of the use of the adhesive, it is difficult to remove, and the 1a metal ring is difficult to recycle; at the clearance between 1a and 8, lapping liquid also can splash, and the clearance is narrow and small, and 1a becket is because metal is hydrophilic material, washs also difficult sanitization, has the risk that has residual lapping liquid, falls to will cause the mar on the wafer surface after having the drying.

In addition, the integral coating type, in which the metal insert is coated with the resin layer, does reduce the leakage of the adhesive and the poor adhesion, and the resin layer itself is a hydrophobic material, so that the scratches are reduced. However, the metal ring is completely wrapped and is shaped, so that it is difficult to take out and reuse the metal ring, and the amount of the resin used is much more than that of the adhesive layer, and the resin is high-performance resin and expensive, so that the cost is high.

The invention content is as follows:

in view of the shortcomings of the prior art, an object of the embodiments of the present invention is to provide a retaining ring for CMP polishing, so as to solve the above-mentioned problems of the conventional retaining ring in the background art, such as the risk of detachment of the bonding interface, and leakage and poor bonding of the adhesive.

In order to achieve the purpose, the invention provides the following technical scheme:

a retaining ring for CMP polishing comprises a metal ring and a wear resin ring, wherein the metal ring and the wear resin ring are connected by adopting a dovetail structure.

As a further scheme of the invention, the inner and outer ring surfaces of the metal ring are coated with a hydrophobic coating, wherein the surface energy of the hydrophobic coating is not more than 100mJ/m ² 。

As a further scheme of the invention, the abrasion resin ring is provided with a groove for grinding fluid to flow, a dovetail groove structure connected with the metal ring and used for limiting the left and right movement, and a bump limit which is uniformly distributed and inserted into the metal ring and used for limiting the rotation movement.

As a further scheme of the invention, the number of the bump limit is not less than 3.

As a further scheme of the invention, the metal ring is provided with a screw hole connected with the grinding head, a dovetail structure connected with the worn resin ring for limiting left and right movement and positioning grooves uniformly distributed for limiting rotary movement by inserting the worn resin ring, and the number of the positioning grooves is not less than 3.

As a further scheme of the invention, the dovetail groove structure and the dovetail structure are connected to form the dovetail groove structure, and the bump limit is clamped with the positioning groove.

As a further aspect of the present invention, the metal ring is made of SUS stainless steel material.

In a further embodiment of the present invention, the hydrophobic coating layer is made of at least one of Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide (PA), polybenzimidazole (PBI), polytetrafluoroethylene (PTFE), epoxy resin (EP), and polyethylene terephthalate (PET). Preferably, the hydrophobic coating comprises a transition layer consisting of a blend of PEEK plus 30% PTFE and a hydrophobic outer layer consisting of PTFE, the combination allowing the hydrophobic coating to achieve a lower surface energy, minimizing the sticking of the grinding fluid during grinding, and the combination allowing the hydrophobic coating to also have a better adhesion to the metal ring.

In a further embodiment of the present invention, the resin ring is at least one of Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide, polybenzimidazole (PBI), polycarbonate, acetal, polyether amide (PEI), polybutylene terephthalate (PBT), and polyethylene terephthalate (PET).

The invention has the following beneficial effects: the retaining ring of the chemical mechanical polishing equipment simultaneously meets the advantages of an adhesive ring and an integrally-coated ring, also meets the problem of metal ring recovery, can prevent leakage, is buckled with a dovetail groove structure together, and has low cost and simple process.

To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Description of the drawings:

fig. 1 is a schematic structural view of a chemical mechanical polishing apparatus in the prior art.

Fig. 2 is a schematic view of a retaining ring structure for CMP polishing according to the present invention.

Fig. 3 and 4 are schematic sectional viewsbase:Sub>A-base:Sub>A and B-B of fig. 2, respectively.

The specific implementation mode is as follows:

the invention will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown.

Referring to fig. 2 to 4, a retainer ring for CMP polishing includes a metal ring 24 and a wear resin ring 22, the metal ring 24 and the wear resin ring 22 being coupled in a dovetail structure; as shown in figure 3, the metal ring and the abrasion resin ring are connected through a dovetail groove type structure, so that the cost is low, the process is simple, the problem of metal ring recovery is solved, and leakage can be prevented.

The structure of the abrasion resin ring 22 is provided with a groove 27 for grinding fluid to flow, the abrasion resin ring comprises a dovetail groove structure 25 which is connected with a metal ring 24 and limits left and right movement, and comprises bump limit 26 which is uniformly distributed and inserted into the metal ring and limits rotary movement, and the number of the bump limit is not less than 3;

the metal ring structure comprises a screw hole connected with the grinding head, a dovetail structure connected with the wear resin ring and used for limiting left and right movement, and positioning grooves 23 uniformly distributed in a manner that the wear resin ring is inserted into the positioning grooves and used for limiting rotary movement, wherein the number of the positioning grooves is not less than 3, a layer of hydrophobic coating 21 is arranged on the surfaces of the inner ring and the outer ring of the metal ring, and the surface energy of the hydrophobic coating 21 is not more than 100mJ/m2.

The present invention is mounted on a chemical mechanical polishing apparatus in which a wafer is accommodated in association with a retainer ring coupled to the chemical mechanical polishing apparatus around the wafer. Referring to fig. 3 and 4, the cmp retainer ring comprises two parts, a metal ring 24 and a resin ring 22, wherein the metal ring 24, made of a metal material, preferably SUS stainless steel, has a hydrophobic coating 21 on its surface, is mounted on the head, and is connected by a corresponding chemical-mechanical connection, ensuring the standard precision and rigidity required for the equipment. Further, the lower portion of the metal ring 24 has a resin ring 22, the lower surface of which is in contact with a polishing pad of a chemical mechanical polishing apparatus. The bottom of the resin ring 22 has an abrasive supply groove for supplying abrasive for the flow of the abrasive liquid.

A specific example is provided below

Example 1

Referring to fig. 2 to 4, a retaining ring for CMP polishing is manufactured by machining a metal ring 24, the metal ring is made of stainless steel 304, a screw hole and a positioning pin 20 connected to a polishing head are formed on the top of the metal ring 24, a dovetail groove 25 and a positioning groove 23 for limiting left and right movement of a resin ring are formed on the bottom of the metal ring 24, the dovetail groove 25 is machined along the inner circumference and the outer circumference, the dovetail groove has an angle of not more than 90 °, preferably 45 °, the positioning groove is uniformly distributed on the circumferential surface, and then a hydrophobic coating 21 is sprayed on the surface of the metal ring 24, wherein the hydrophobic coating 21 may be made of Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide (PA), polybenzimidazole (PBI), polytetrafluoroethylene (PTFE), epoxy resin (EP), or polyethylene terephthalate (PET), such as any known engineering plastic or any known ceramic material of silicon carbide (SiC), boron Nitride (BN), aluminum oxide (Al 2O 3), and silicon oxide (Si 3O 4).

After the coating is cured, the coating is placed in a mold, resin is injected to form a resin ring 22 on the surface of the metal ring, and the metal ring is cooled and taken out. The resin ring 22 is made of Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide, polybenzimidazole (PBI), polycarbonate, acetal, polyether amide (PEI), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), for example, any one of known engineering plastics, and other material-modified engineering plastics. The other modified materials can be inorganic matters such as glass fiber, carbon fiber, mineral powder and the like, and can also be organic matters such as aramid fiber, compatilizer, blending alloy material and the like.

Example 2

Referring to fig. 2-4, a retaining ring for CMP polishing is manufactured by machining a metal ring 24, the metal ring is made of stainless steel 304, a screw hole and a positioning pin 20 connected to a polishing head are formed on the top of the metal ring 24, a dovetail groove 25 and a positioning groove 23 for limiting left and right movement of a resin ring are formed on the bottom of the metal ring 24, the dovetail groove 25 is unevenly distributed on the circumference and is distributed in sections, the included angle of the dovetail groove is closer to 90 degrees, preferably 85 degrees, and then a hydrophobic coating 21 is sprayed on the surface of the metal ring 24, wherein the hydrophobic coating 21 may be made of Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide (PA), polybenzimidazole (PBI), polytetrafluoroethylene (PTFE), epoxy resin (EP), or polyethylene terephthalate (PET), such as any known engineering plastic or any known ceramic material of silicon carbide (SiC), boron Nitride (BN), aluminum oxide (Al 2O 3), and silicon oxide (Si 3O 4).

After the coating is cured, the resin ring 22 is placed in a mold, the resin pipe is used for processing the resin ring 22, the resin ring 22 is provided with a buckling position corresponding to the metal ring 24, and the resin ring 22 is heated to a certain degree, so that the buckling piece is slightly softened and then is pressed into the metal ring 24. The resin ring 22 is made of Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide, polybenzimidazole (PBI), polycarbonate, acetal, polyetheramide (PEI), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), for example, any one of known engineering plastics, and other material-modified engineering plastics. The other modified materials can be inorganic matters such as glass fiber, carbon fiber, mineral powder and the like, and can also be organic matters such as aramid fiber, compatilizer, blending alloy material and the like.

The technical principle of the present invention has been described above with reference to specific embodiments, which are merely preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. Other embodiments of the invention will occur to those skilled in the art without the exercise of inventive faculty, and such will fall within the scope of the invention.

Claims

1. A retaining ring for CMP grinding, which is characterized by comprising a metal ring and a wear resin ring, wherein the metal ring and the wear resin ring are connected by adopting a dovetail groove type structure, the surfaces of the inner ring and the outer ring of the metal ring are coated with a hydrophobic coating, and the surface energy of the hydrophobic coating is not more than 100mJ/m ² 。

2. The retainer ring for CMP polishing according to claim 1, wherein the abrasive resin ring is provided with a groove for slurry flow, with a dovetail groove structure connected to the metal ring to restrict a lateral movement, and with a convex stopper uniformly inserted into the metal ring to restrict a rotational movement.

3. The retainer ring for CMP polishing according to claim 2, wherein the number of the bump stoppers is not less than 3.

4. The retainer ring for CMP polishing as claimed in claim 1, wherein the metal ring is provided with a screw hole connected to the polishing head, with a dovetail structure connected to the wear resin ring to restrict the left and right movement, and with positioning grooves uniformly distributed so that the wear resin ring is inserted to restrict the rotational movement, and the number of the positioning grooves is not less than 3.

5. The retainer ring for CMP polishing according to claim 4, wherein the dovetail groove structure is connected to the dovetail structure to form the dovetail groove structure, and the bump stopper is engaged with the positioning groove.

6. The retainer ring for CMP polishing as recited in claim 1, wherein the metal ring is made of SUS stainless material.

7. The retainer ring for CMP polishing according to claim 1, wherein the hydrophobic coating layer is at least one of Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide (PA), polybenzimidazole (PBI), polytetrafluoroethylene (PTFE), epoxy resin (EP), and polyethylene terephthalate (PET).

8. The retainer ring for CMP abrasive according to claim 7, wherein the resin ring employs at least one of Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide, polybenzimidazole (PBI), polycarbonate, acetal, polyetheramide (PEI), polybutylene terephthalate (PBT), and polyethylene terephthalate (PET).