KR-102963819-B1 - POLISHING CARRIER HEAD WITH PIEZOELECTRIC PRESSURE CONTROL

Abstract

A carrier head for holding a substrate in a polishing system comprises a housing including a carrier plate, a first flexible membrane fixed to the housing, and a plurality of independently operable piezoelectric actuators fixed to the carrier plate. The first flexible membrane has an upper surface and a lower surface providing a substrate mounting surface. The piezoelectric actuators are positioned on the first flexible membrane to independently adjust the compression pressure on the upper surface of the first flexible membrane.

Inventors

• 브라운, 브라이언 제이.
• 나겐가스트, 앤드류 제이.
• 웡, 저스틴 호 쿠엔

Assignees

• 어플라이드 머티어리얼스, 인코포레이티드

Dates

Publication Date

20260513

Application Date

20210622

Priority Date

20200624

Claims (10)

1. As a grinding assembly, Drive shaft; A carrier head for holding a substrate in a polishing system - the carrier head is, A housing fixed to the drive shaft and movable by the drive shaft - the housing includes a carrier plate -, A plurality of independently operable piezoelectric actuators fixed to the carrier plate to independently adjust the pressure on the substrate maintained by the carrier head, and circuit fixed to the above housing Includes -; A motor for rotating the above drive shaft; Rotating electric coupler; Controller; Voltage supply line and data line connecting the controller to the circuit through the above rotary electric coupling Includes, The above circuit is configured to receive voltage on a voltage supply line, receive data on a data line, and control voltages applied to the plurality of piezoelectric actuators based on the data, and A grinding assembly comprising a microcontroller configured such that the controller is configured to generate data on the data line including a plurality of frames, and the circuit fixed to the housing is configured to determine for each frame at least one control voltage to be applied to at least one of the plurality of piezoelectric actuators based on the data within the frames.
2. delete
3. A grinding assembly according to claim 1, wherein the controller is configured to generate a frame of data having control values for each piezoelectric actuator, and the microcontroller is configured to determine which control value is associated with each piezoelectric actuator by the order of the control values within the frame.
4. A grinding assembly according to claim 1, wherein the controller is configured to generate a frame of data including both a control value and an identification value for the piezoelectric actuator to which the control value is applied, and the microcontroller is configured to determine an appropriate piezoelectric actuator for the control value based on the identification value.
5. In claim 1, the circuit is a polished assembly mounted on the uppermost part of the housing.
6. In paragraph 1, the circuit is a grinding assembly mounted inside the carrier head.
7. In claim 1, the polishing assembly wherein the plurality of independently operable piezoelectric actuators are positioned at different angular positions around the central axis of the carrier head.
8. In claim 7, the polishing assembly wherein a plurality of independently operable piezoelectric actuators are positioned to control pressure on the edge portion of the rear surface of the substrate.
9. In claim 8, the plurality of piezoelectric actuators comprises at least one piezoelectric actuator every 30° around the central axis of the carrier head, forming a grinding assembly.
10. A polishing assembly according to claim 7, wherein the controller is configured to control voltages applied to the plurality of piezoelectric actuators such that, as the substrate rotates in the carrier head, the position on the rear edge of the substrate to which the highest pressure is applied rotates relative to the carrier head.

Description

Polishing Carrier Head with Piezoelectric Pressure Control The present disclosure generally relates to profile control of a polishing process, and more specifically, to a carrier head having piezoelectric actuators. Integrated circuits are typically formed on a substrate (e.g., a semiconductor wafer) by sequentially depositing conductive, semiconducting, or insulating layers on a silicon wafer and subsequent processing of the layers. One manufacturing step involves depositing a filler layer on a non-planar surface and planarizing the filler layer. For certain applications, the filler layer is planarized until the top surface of the patterned layer is exposed. Additionally, planarization can be used for lithography, for example, to planarize the substrate surface of a dielectric layer. Chemical mechanical polishing (CMP) is an accepted method of planarization. This planarization method typically requires a substrate to be mounted on a carrier head. An exposed surface of the substrate is positioned against a rotary polishing pad. The carrier head provides a controllable load on the substrate to press the substrate against the polishing pad. In some situations, the carrier head includes a membrane forming a plurality of independently pressurizable chambers, and the pressure in each chamber controls the polishing rate in each corresponding area on the substrate. A polishing liquid, such as a slurry containing abrasive particles, is supplied to the surface of the polishing pad. In one aspect, a carrier head for holding a substrate in a polishing system comprises a housing including a carrier plate, a first flexible membrane fixed to the housing, and a plurality of independently operable piezoelectric actuators fixed to the carrier plate. The first flexible membrane has an upper surface and a lower surface providing a substrate mounting surface. The piezoelectric actuators are positioned on the first flexible membrane to independently adjust a compression pressure on the upper surface of the first flexible membrane. In another aspect, the polishing system includes a platen for supporting a polishing pad, a carrier head for holding a substrate against the polishing pad, an in-situ monitoring system for generating a signal according to the thickness of a layer on the substrate being polished, and a control system. The carrier head includes a housing that is fixed to a drive shaft and rotatable by the drive shaft—the housing includes a carrier plate—a first flexible membrane fixed to the housing, and a plurality of independently operable piezoelectric actuators. The first flexible membrane has an upper surface and a lower surface providing a substrate mounting surface. The piezoelectric actuators are fixed to the carrier plate and positioned on the first flexible membrane to independently adjust the compressive pressure on the upper surface of the first flexible membrane. The plurality of piezoelectric actuators are arranged at different angular positions around the central axis of the carrier head. The control system is configured to control voltages applied to the plurality of piezoelectric actuators based on a signal from the in-situ monitoring system to reduce angular variation in the thickness of the layer. In another aspect, the polishing assembly includes a carrier head for holding a substrate in a polishing system, a drive shaft, a motor for rotating the drive shaft, a rotary electric coupling, a controller, a voltage supply line, and a data line. The carrier head includes a housing that is fixed to the drive shaft and rotatable by the drive shaft and includes a carrier plate, a plurality of independently operable piezoelectric actuators, and a circuit fixed to the housing. The piezoelectric actuators are fixed to the carrier plate and positioned to independently adjust pressure on the substrate. The voltage supply line and the data line connect the controller to the circuit through the rotary electric coupling. The circuit is configured to receive voltage on the voltage supply line, receive data on the data line, and control the voltages applied to the plurality of piezoelectric actuators based on the data. In another aspect, a carrier head for holding a substrate in a polishing system comprises a housing, a first flexible membrane fixed to the housing to form one or more pressurizable chambers for applying pressure to a central portion of the substrate through a central membrane portion of the first flexible membrane, and a plurality of independently operable piezoelectric actuators supported by the housing—the plurality of piezoelectric actuators are positioned radially outward of the central membrane portion and at different angular positions to independently adjust pressure to a plurality of angular zones of an annular outer region of the substrate surrounding the central portion of the substrate. In another aspect, a carrier head for holding a substrate in a polishing system comprises a housing and a f