Drive Ring Vibration Damping in Substrate Holding Apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor device fabrication, the increasing number of interconnect levels leads to reduced step coverage and surface irregularities, necessitating improved planarization to prevent 'rounded edges' and vibrations during chemical mechanical polishing, which can result in uneven polishing and substrate slippage.
Innovation Solution
A substrate holding apparatus with a drive ring composed of materials with varying moduli of longitudinal elasticity, specifically using rubber for vibration damping, to reduce vibrations transmitted from the retaining ring to the top ring body, thereby stabilizing the polishing process and preventing substrate slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a retaining ring is used to press the polishing pad to control polishing amount at the edge portion, then rounded edge is prevented, but vibrations occur under high frictional forces and low relative speed conditions
Solution Approach 1:
A damper is introduced as an intermediary component between the retaining ring and the top ring body. The damper absorbs vibrations generated during polishing, particularly under high frictional forces and low relative speed conditions, while allowing the retaining ring to maintain its function of pressing the polishing pad to prevent rounded edges.
Solution Approach 2:
The vibration damper converts the harmful vibrations generated during polishing into beneficial damping effects. By absorbing and dissipating vibrational energy, the damper transforms the harmful mechanical vibrations into heat energy through internal friction, thereby stabilizing the polishing process.
2Reliability
If the substrate holding apparatus vibrates under strict polishing conditions, then the actual range of polishing conditions becomes narrower, but polishing performance is improved
Solution Approach 1:
The vibration damper converts harmful vibrations into beneficial damping effects, allowing the system to operate reliably under a broader range of polishing conditions. By dissipating vibrational energy, the damper expands the usable process window while maintaining polishing performance.
3Productivity
If frictional force between substrate and polishing pad is high, then polishing efficiency is improved, but substrate may slip out of top ring due to vibrations
Solution Approach 1:
The damper serves as an intermediary between the retaining ring and the top ring body, absorbing vibrations generated during high-friction polishing. This vibration absorption prevents substrate slippage while allowing high frictional forces to be applied for improved polishing efficiency.
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 solution effectively dampens vibrations, ensuring uniform polishing pressure and preventing substrate slippage, thereby broadening the process window and improving polishing performance by maintaining stable contact between the substrate and polishing pad.
Implementation Method 1
a second material having a modulus of longitudinal elasticity smaller than the first material... vibrations generated in the retaining ring during polishing are damped by the second material when the vibrations are transmitted from the first material to the second material of the drive ring
Implementation Method 2
The second material comprises a rubber material... vibrations generated in the retaining ring during polishing are damped by the second material
Data Source
AI summary
A substrate holding apparatus and a polishing apparatus which can reduce vibrations of a top ring in its entirety by damping vibrations transmitted from a retaining ring to a top ring body is disclosed. The substrate holding apparatus includes a top ring body having a substrate holding surface configured to hold and press a substrate against a polishing surface, a retaining ring configured to surround the substrate and to contact the polishing surface, and a drive ring comprising a ring member configured to hold the retaining ring on a lower surface thereof, a central member disposed at a central part of the top ring body and supported by the top ring body, and a connecting portion configured to connect the ring member and the central member. The drive ring includes a first material and a second material having a modulus of longitudinal elasticity smaller than the first material.