Stepped Retaining Ring Bonding for CMP Slurry Delamination
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Solution Overview
Problem
Conventional retaining rings used in chemical mechanical polishing (CMP) processes face issues with slurry accumulation, delamination, and reduced lifespan due to inadequate bonding and stress distribution, leading to inefficiencies and equipment failure.
Innovation Solution
A retaining ring design featuring an annular lower portion with a step and an annular rigid upper portion, bonded with a high-strength adhesive layer, which includes epoxy materials, provides enhanced bonding and stress distribution, preventing slurry accumulation and delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional retaining ring is used in CMP processes, then the substrate can be held in place during polishing, but slurry accumulates between the upper and lower portions leading to delamination and reduced lifespan
Solution Approach 1:
The retaining ring is divided into an upper portion and a lower portion that can be separately assembled. The lower portion includes an annular recess that receives the upper portion, creating a segmented structure that prevents slurry accumulation between portions while maintaining bonding strength through the bonding layer at the interface.
Solution Approach 2:
The harmful factor of slurry accumulation is extracted or eliminated by designing the bonding interface such that slurry cannot penetrate or accumulate between the upper and lower portions. The bonding layer acts as a barrier that prevents slurry ingress, thereby removing the source of delamination and reliability issues.
2Reliability
If a bonding layer is added between the upper and lower portions, then delamination is prevented, but manufacturing complexity increases
Solution Approach 1:
The retaining ring is segmented into upper and lower portions with a defined bonding interface. The annular recess in the lower portion and corresponding protrusion in the upper portion create a standardized joining geometry that simplifies the bonding process while ensuring reliable adhesion under chemical, thermal, and mechanical loads during CMP operations.
Solution Approach 2:
The bonding layer is applied locally at the bonding interface between the upper and lower portions, specifically at the annular recess region. This localized bonding approach provides sufficient adhesion strength where needed without requiring complex bonding structures throughout the entire retaining ring, thereby maintaining manufacturing simplicity.
3Ease of manufacture
If the bonding interface is simplified, then manufacturing is easier, but stress distribution becomes inadequate leading to premature failure
Solution Approach 1:
The bonding interface is simplified through segmentation into an annular recess in the lower portion and a corresponding protrusion in the upper portion. This segmented design provides adequate stress distribution across the bonding interface while maintaining ease of manufacture, as the geometric features guide proper alignment and bonding without requiring complex bonding procedures.
Solution Approach 2:
The bonding interface concentrates the bonding layer at the annular recess region where stress occurs during CMP operations. This localized quality approach ensures adequate stress distribution at the critical bonding interface while keeping the overall manufacturing process simple, as bonding is required only at this specific location rather than throughout the entire structure.
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
The design enhances the bonding strength and durability of the retaining ring, reducing the likelihood of delamination and extending its useful life by distributing stress effectively and maintaining adhesion under chemical, thermal, and mechanical loads.
Implementation Method 1
A bonding layer is between the step and the recess
Data Source
AI summary
A two part retaining ring is described. A rigid upper portion has an annular recess along its inner diameter. An annular wearable lower portion has an inner diameter, an annular extension defined by the inner diameter and a vertical wall that is perpendicular to a surface of the second portion and opposite to the inner diameter. The annular extension fits into the annular recess of the annular first portion. A bonding material is on the vertical wall of the annular second portion.