CMP Polishing Pad Composition for Low-Hardness Defect Control
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Solution Overview
Problem
Existing polishing pads used in chemical mechanical planarization (CMP) processes suffer from increased hardness, leading to surface defects such as residues, scratches, and chatter marks on semiconductor substrates, and poor polishing performance due to surface roughness reduction and recovery elasticity issues.
Innovation Solution
A polishing pad with a polishing layer composed of a urethane-based prepolymer, a curing agent containing a tertiary amine-based polyol with an ether bond, and a foaming agent, which maintains a surface roughness reduction rate (RSk) of less than 50% and a recovery elasticity resistance index (RERI) of 40 or less, thereby controlling surface defects and enhancing polishing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MOCA is used as a curing agent to enhance polishing rate and stability, then polishing performance is improved, but the hardness of the polishing pad increases causing severe hardening, pad glazing, and surface defects
Solution Approach 1:
The patent changes the chemical composition parameters of the curing agent from conventional options (like MOCA) to a specific combination of aromatic amine compound and cyclic carboxylic acid compound. This parameter change in the curing agent composition enables the polishing pad to achieve both high polishing rate and low hardness, resolving the contradiction between productivity and strength.
Solution Approach 2:
The patent uses a composite curing agent system comprising both aromatic amine compound and cyclic carboxylic acid compound, rather than a single curing agent. This composite approach allows the polishing pad to exhibit balanced properties with improved polishing performance while maintaining low hardness and preventing pad glazing.
2Reliability
If the hardness of the polishing pad is increased to improve polishing stability, then polishing stability is improved, but surface defects such as residues, scratches, and chatter marks increase
Solution Approach 1:
The patent changes the physical and chemical parameters of the polishing pad by using a specific curing agent composition (aromatic amine compound with cyclic carboxylic acid compound). This parameter change achieves the counterintuitive result of improving polishing stability while simultaneously reducing surface defects, as the low hardness prevents excessive stress on the substrate surface.
3Productivity
If the surface roughness reduction rate is increased to improve polishing performance, then polishing performance is improved, but the recovery elasticity index increases causing pad glazing
Solution Approach 1:
The patent changes the compositional parameters of the polishing pad by introducing a cyclic carboxylic acid compound as part of the curing agent system. This modification controls the crosslinking density and network structure, achieving high polishing performance while maintaining low recovery elasticity index to prevent pad glazing.
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 polishing pad achieves low hardness, reduces surface defects, and maintains consistent polishing rates by controlling surface roughness reduction and elasticity, resulting in improved mechanical properties and reduced glazing phenomena.
Implementation Method 1
the curing agent comprises a tertiary amine-based polyol containing an ether bond
Implementation Method 2
the polishing layer comprises a cured product of a composition comprising a urethane-based prepolymer, a curing agent
Implementation Method 3
by generating a gas by a chemical reaction
Implementation Method 4
The CMP process is carried out on a certain side of an object to be polished for the purposes of planarization of the side to be polished, removal of aggregated materials
Data Source
AI summary
The present invention relates to a polishing pad for use in a chemical mechanical planarization (CMP) process of semiconductors, to a process for preparing the same, and to a process for preparing a semiconductor device using the same. The polishing pad according to an embodiment can achieve low hardness by comprising a polishing layer formed using a curing agent of specific components. It is possible to enhance the mechanical properties of the polishing pad, as well as to improve the surface defects appearing on the surface of a semiconductor substrate, by controlling the surface roughness reduction rate and the recovery elasticity index of the polishing pad to specific ranges. It is also possible to further enhance the polishing rate.