Chemical Mechanical Polishing Retainer Ring Anti-Twist Design
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Solution Overview
Problem
Conventional retainer rings in chemical-mechanical polishing devices for semiconductor wafers suffer from twisting, leading to uneven surface polishing, increased defective proportions, and high production costs due to corrosion and uneven slurry flow, as well as difficulties in attachment and detachment.
Innovation Solution
A retainer ring design featuring a resin first member with a metal second member embedded inside, connected without bonding, using bolts and a spring pin for secure attachment, and incorporating a through hole for smooth slurry flow, preventing twisting and corrosion-induced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bonding is used to connect the first member and second member, then the retainer ring can prevent deformity and damages, but particles are generated by corrosion of the slurry due to bonding
Solution Approach 1:
The patent removes the bonding agent from the system by using a press-fit structure where the first member is directly inserted into the second member without any adhesive. This eliminates the source of particle generation while maintaining structural integrity through precise dimensional design and interference fit
Solution Approach 2:
The patent introduces a press-fit interface as an intermediary mechanism between the first member and second member. This mechanical coupling method serves as a mediator that transfers load and maintains connection without requiring chemical bonding, thus avoiding particle generation from slurry corrosion of adhesives
2Ease of manufacture
If the retainer ring is made as a single piece, then manufacturing is simpler, but it cannot be easily attached or detached
Solution Approach 1:
The retainer ring is divided into two separate members: the first member (polishing pad contact portion) and the second member (carrier connection portion). These segmented components can be independently manufactured and then easily assembled through press-fit, enabling both simple manufacturing and easy attachment/detachment operations
3Ease of manufacture
If the retainer ring structure is simplified, then production cost is reduced, but twisting occurs leading to uneven polishing
Solution Approach 1:
The patent creates a composite structure by combining the first member (polishing pad contact portion) and second member (carrier connection portion) through press-fit. This composite design provides enhanced structural stability and twisting resistance while maintaining cost-effectiveness, as the combined structure distributes mechanical loads more effectively than a simplified single-piece design
4Device complexity
If the slurry flow path is not optimized, then the structure is simpler, but the slurry flow is not smooth leading to non-uniform polishing
Solution Approach 1:
The patent optimizes the slurry flow path by creating specific local features within the retainer ring structure. The flow path is designed with varying cross-sections and channels in critical areas to ensure smooth slurry circulation, while other non-critical areas maintain simple structures. This localized optimization improves polishing uniformity without significantly increasing overall structural complexity
Data Source
AI summary
A retainer ring of a chemical-mechanical polishing device which can prevent itself from being twisted and improve defective proportion and equipment operating rate occurred when polishing semiconductor wafers by embedding a metal member inside.Retainer ring installed to a polishing head of a chemical mechanical polishing device to fix a semiconductor wafer includes: a first member of a resin connected to a carrier of the polishing head and a room is formed inside; a second member of a metal embedded into the room of the first member.The present invention can improve a defective proportion of a semiconductor wafer polishing process by above effects and can reduce initial limitation conditions accompanied to mass production to increase an equipment operation rate by providing credibility of the retaining ring.