CMP System with Self-Refreshing Grinding Head
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Solution Overview
Problem
Current chemical mechanical polishing systems face inefficiencies in achieving uniformity and flatness of wafers due to limitations in mechanical and chemical action, particularly in removing debris and maintaining polishing pad effectiveness.
Innovation Solution
The system incorporates a polishing head with a grinding piece and diamond grinding particles that rotate independently of the polishing pad, applying a downward force and gas pressure to ensure effective contact and removal of debris, while the polishing pad is rotated to enhance grinding efficiency and pad refurbishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the polishing pad is rotated to enhance grinding efficiency, then the mechanical polishing efficiency is improved, but the polishing pad wears out faster
Solution Approach 1:
The patent applies self-refreshing grinding pieces that continuously remove worn material from the polishing pad surface and replace it with fresh grinding surfaces. This allows the system to discard worn pad material and recover functionality by regenerating the grinding surface in real-time, thus maintaining high polishing efficiency while extending effective pad life.
2Manufacturing precision
If a traditional polishing system is used, then the structure is simpler, but the wafer flatness and thickness uniformity are insufficient
Solution Approach 1:
The patent segments the polishing system into multiple independent functional modules: a rotating polishing pad, independently rotating polishing heads with multiple wafers, and self-refreshing grinding pieces. This segmentation allows each module to be optimized for precision while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent introduces dynamic elements including independent rotation of polishing heads relative to the pad, adjustable downward forces on each head, and continuously self-refreshing grinding surfaces. These dynamic adjustments enable real-time optimization of contact pressure and grinding efficiency, achieving superior wafer flatness and thickness uniformity.
3Productivity
If multiple wafers are polished simultaneously, then the productivity increases, but the system complexity increases
Solution Approach 1:
The patent merges multiple wafer polishing operations into a single integrated system where multiple polishing heads, each holding wafers, operate simultaneously on a single rotating pad. The independent rotation and control of each head allow multiple wafers to be processed in parallel while maintaining individual precision, thus increasing throughput without proportionally increasing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves the mechanical and chemical polishing efficiency, leading to increased wafer flatness and thickness uniformity, simplifies the system structure, and reduces manufacturing costs by allowing simultaneous polishing of multiple wafers and extended pad life.
Implementation Method 1
a gas source 140. The chamber 132 is fluidly connected to the gas source 140. During operation, the gas source 140 supplies a gas G to the chamber 132 such that the wafer 300 communicated with the chamber 132 through the membrane 133 is pressed against the polishing pad 200
Implementation Method 2
During the process, the wafer is compressed towards the polishing pad and both the wafer and the polishing pad are rotated. Thus, the wafer is rubbed against the polishing pad. Together with the chemical action of the slurry, this can remove material and tend to even out any irregular topography
Implementation Method 3
Chemical mechanical polishing is a process in which an abrasive slurry and a polishing pad work simultaneously together in both the chemical and mechanical approaches to flatten a wafer
Data Source
AI summary
A chemical mechanical polishing system includes a platen, a slurry introduction device and at least one polishing head. The platen is configured to allow a polishing pad to be disposed thereon. The slurry introduction device is configured to supply slurry onto the polishing pad. The polishing head includes a main body and at least one grinding piece. The main body has an accommodation space for accommodating a wafer. The grinding piece is disposed on the main body. The grinding piece has a grinding surface configured to grind against the polishing pad.