CN-122008063-A - Carrier head for chemical mechanical polishing, polishing system and polishing method

CN122008063ACN 122008063 ACN122008063 ACN 122008063ACN-122008063-A

Abstract

The invention discloses a bearing head for chemical mechanical polishing, a polishing system and a polishing method, and belongs to the technical field of semiconductor manufacturing. The bearing head comprises a base, a gas film assembly, a retaining ring and a driving assembly, wherein the gas film assembly is arranged below the base and used for loading wafers to be polished, the retaining ring is arranged below the base and is positioned on the outer periphery side of the gas film assembly, the retaining ring comprises a fixed piece, a movable piece and a driving assembly, the fixed piece is arranged below the base, the movable piece is arranged in the fixed piece in a sliding mode, a groove for conveying polishing liquid is formed between the bottom surface of the movable piece and the bottom surface of the fixed piece, the driving assembly is arranged between the base and the movable piece and connected with the movable piece, and the driving assembly is used for responding to abrasion of the movable piece and actively driving the movable piece to move vertically so as to compensate abrasion loss of the bottom surface of the movable piece and maintain constant depth of the groove.

Inventors

WANG TONGQING
MENG SONGLIN
SHANG YONGCHAO
JIN JUN
ZHANG HONGJIAO
ZUO SHAOJIE
LI KUN

Assignees

华海清科(上海)半导体有限公司

Dates

Publication Date: 20260512
Application Date: 20251225

Claims (16)

1. A carrier head for chemical mechanical polishing, comprising: A base; the air film assembly is arranged below the base and used for loading wafers to be polished; the retaining ring is arranged below the base and is positioned on the outer periphery side of the air film assembly; The retaining ring includes: the fixing piece is arranged below the base; the movable piece is arranged in the fixed piece in a sliding way, and a groove for conveying polishing liquid is formed between the bottom surface of the movable piece and the bottom surface of the fixed piece; The driving assembly is arranged between the base and the movable piece and connected with the movable piece, so that the driving assembly is actively driven to move vertically in response to the abrasion of the movable piece, the abrasion loss of the bottom surface of the movable piece is compensated, and the depth of the groove is kept constant.
2. The carrier head of claim 1, wherein the fixing member comprises a fixing member body which is a circular wall plate, a plurality of L-shaped limiting portions are uniformly arranged on the inner side of the fixing member body, horizontally extend inwards from the bottom of the fixing member body to form a horizontal section, vertically extend upwards from the end of the horizontal section to form a vertical section, and a first gap is formed between adjacent limiting portions.
3. The carrier head of claim 2, wherein the movable member comprises a movable member body having a circular structure, and wherein a plurality of protrusions are uniformly disposed on an inner side wall of the movable member body, and a second gap is formed between adjacent protrusions.
4. The carrier head of claim 3, wherein a plurality of auxiliary grooves are formed below the movable member body, the auxiliary grooves are communicated with the second gap, the movable member is mounted in the fixed member, the vertical section of the limiting portion is arranged in the second gap, the horizontal section is arranged in the auxiliary grooves, and the bottom surface of the horizontal section and the auxiliary grooves form the grooves.
5. The carrier head of claim 3, wherein the driving assembly comprises an upper pressing ring, a pressing film and a lower pressing ring, the upper pressing ring is fixed on the base, an annular cavity groove which is opened downwards is formed in the upper pressing ring, and the pressing film is arranged in the cavity groove and is fixed on the upper pressing ring through the lower pressing ring.
6. The carrier head of claim 5, wherein the upper compression ring is disposed concentrically within the stationary member, and the compression membrane is coupled to the top surface of the movable member.
7. The bearing head according to claim 6, wherein the upper pressing ring comprises an outer side plate, a top plate and an inner side plate, which are integrally formed, the top plate is mounted on the base, and a cavity groove formed by the outer side plate and the inner side plate is covered on the upper portion of the movable piece.
8. The carrier head of claim 7, wherein said inner side plate is uniformly provided with a plurality of recesses having a size matching the size of said bumps, and wherein adjacent ones of said recesses form a spacer plate having a size matching the size of said second gap.
9. The carrier head of claim 8, wherein the height of the projection is smaller than the height of the movable member main body, the spacer is inserted into the second gap, and the notch of the upper pressing ring corresponds to the projection of the movable member.
10. The carrier head of claim 9, wherein the distance between the drive assembly and the movable member in the vertical direction is less than the distance between the projection and the top surface of the movable member body.
11. A carrier head according to claim 3, wherein a micro-gap is formed between the bump and the limiting portion, the micro-gap is tapered, and the gap between the bump and the limiting portion is gradually reduced from inside to outside.
12. The carrier head according to claim 11, wherein the projection is provided with a plurality of projections on a side surface of the projection facing the stopper portion, for disrupting continuity of the polishing waste liquid entering the micro gap.
13. The carrier head of claim 11, wherein the base is configured with purge channels extending to the micro-gaps, the purge channels injecting fluid to purge contaminants residing in the micro-gaps.
14. A polishing system comprising a polishing platen, a liquid supply device for supplying a polishing liquid toward a space between the polishing platen and a wafer, a dressing device for dressing a surface of the polishing platen, and the carrier head according to any one of claims 1 to 13, the carrier head pressing the wafer to be polished against the polishing platen.
15. A polishing method using the polishing system of claim 14, comprising: the bearing head loads the wafer to be polished and presses the wafer to be polished against the polishing pad above the polishing disc, and the liquid supply device supplies polishing liquid between the wafer and the polishing pad so as to carry out chemical mechanical polishing on the wafer; In the wafer polishing process, fluid is sprayed towards the micro-gap between the limiting part of the fixed part and the protruding block of the movable part through the cleaning pore canal so as to prevent pollutants from entering the inside of the retaining ring.
16. The method of claim 15, wherein the carrier head drives the movable member to reciprocate vertically when the wafer is not polished, and the cleaning port ejects the fluid toward the micro gap to remove contaminants retained in the micro gap.

Description

Carrier head for chemical mechanical polishing, polishing system and polishing method Technical Field Embodiments of the present application relate to the field of semiconductor manufacturing technology, and in particular, to a carrier head for chemical mechanical polishing, a polishing system, and a polishing method. Background The integrated circuit industry is the core of the information technology industry, and plays a key role in the process of converting and upgrading the boosting manufacturing industry into digital and intelligent. The chip is a carrier of an integrated circuit, and the chip manufacturing involves the process flows of integrated circuit design, wafer manufacturing, wafer processing, electrical measurement, dicing packaging, testing, and the like. Among them, chemical Mechanical Polishing (CMP) belongs to one of five main core processes in the wafer manufacturing process. CMP is a globally planarized ultra-precise surface processing technique. The chemical mechanical polishing generally attracts a wafer to the bottom surface of a carrier head, the surface of the wafer with a deposition layer is abutted against the upper surface of a polishing pad, the carrier head rotates in the same direction with the polishing pad under the actuation of a driving component and gives a downward load to the wafer, and polishing liquid is supplied to the upper surface of the polishing pad and distributed between the wafer and the polishing pad, so that the wafer completes the chemical mechanical polishing of the wafer under the combined action of chemistry and machinery. The carrier head is a key component of the CMP system, the lower end of the carrier head is provided with a retaining ring which is mainly used for limiting the position of a polished wafer and preventing the polished wafer from sliding out of the carrier head under the action of lateral force, the bottom end of the retaining ring is provided with a groove for conveying polishing liquid between a polishing pad and the wafer, and in addition, the retaining ring can also participate in the regulation and control of polishing pressure, namely the non-uniformity of the wafer removal rate is improved by regulating the pressure of the retaining ring. The existing retaining ring is a consumable product, and is usually made of wear-resistant polymers (such as PPS and PEEK), and the bottom surface of the retaining ring is inevitably worn with the increase of the number of the polished sheets. This wear results in a reduction in the overall thickness of the retaining ring, which in turn progressively shallower the depth of the groove at its bottom. The variation in groove depth directly affects the cross-sectional area and flow resistance of the fluid channel through which the polishing liquid is supplied to the underside of the wafer. Studies have shown that unexpected changes in trench depth can disrupt the slurry flow field and chemical distribution in the wafer edge region, causing relative changes in the material removal rates at the wafer edge and intermediate locations, thereby exacerbating polishing non-uniformity. Currently, the primary way to solve this problem is to monitor and replace the entire retaining ring periodically, which not only increases consumable costs, but also affects equipment utilization due to downtime replacement. Disclosure of Invention In view of the above, embodiments of the present application provide a carrier head, a polishing system and a polishing method for chemical mechanical polishing, so as to at least partially solve the technical problem that the conventional retaining ring is worn to cause the depth of the groove to change, thereby affecting the stability and uniformity of the polishing process. The main object of the present application is to provide a carrier head that automatically compensates for retainer ring wear to maintain a substantially constant slurry groove depth. According to a first aspect of an embodiment of the present application, there is provided a carrier head for chemical mechanical polishing, including: A base; the air film assembly is arranged below the base and used for loading wafers to be polished; the retaining ring is arranged below the base and is positioned on the outer periphery side of the air film assembly; The retaining ring includes: the fixing piece is arranged below the base; the movable piece is arranged in the fixed piece in a sliding way, and a groove for conveying polishing liquid is formed between the bottom surface of the movable piece and the bottom surface of the fixed piece; The driving assembly is arranged between the base and the movable piece and connected with the movable piece, so that the driving assembly is actively driven to move vertically in response to the abrasion of the movable piece, the abrasion loss of the bottom surface of the movable piece is compensated, and the depth of the groove is kept constant. In some embodiments, the fixing piece