CMP Polishing Pad Composition to Reduce Glazing and Surface Defects
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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, along with poor polishing performance due to surface roughness reduction and glazing phenomena.
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 25 or less, ensuring a hardness of 40 to 50 Shore D, thereby reducing glazing 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 polishing stability, then polishing performance is improved, but 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 MOCA to a specific formula comprising a polyol and a polyisocyanate in defined ratios (polyol: 30-70 parts, polyisocyanate: 30-70 parts). This parameter change resolves the contradiction by achieving appropriate hardness (30-50 Shore D) that maintains polishing performance while preventing excessive hardening and pad glazing
Solution Approach 2:
The patent uses a composite curing agent system combining polyol and polyisocyanate components rather than a single curing agent. This composite approach creates a balanced chemical structure that provides both polishing stability and controlled hardness, avoiding the severe hardening issues associated with MOCA while maintaining effective polishing rate
2Reliability
If MOCA is used as a curing agent to improve polishing stability, then polishing consistency is enhanced, but surface defects such as residues, scratches, and chatter marks increase
Solution Approach 1:
The patent modifies the chemical parameters of the curing agent formulation, specifically using polyol (30-70 parts) and polyisocyanate (30-70 parts) in controlled ratios. This parameter adjustment produces a polishing pad with optimized mechanical properties that maintain polishing stability while minimizing surface defects like residues, scratches, and chatter marks on the semiconductor substrate
Solution Approach 2:
The patent creates local quality variations in the polishing pad structure through controlled pore formation and specific material distribution. The pores are distributed throughout the pad structure to provide localized compliance that reduces surface defects during polishing while maintaining overall polishing stability
3Productivity
If the polishing pad hardness is increased to improve polishing rate, then material removal efficiency is enhanced, but pad glazing and surface roughness reduction rate increase
Solution Approach 1:
The patent optimizes the hardness parameter by selecting specific curing agent formulations (polyol: 30-70 parts, polyisocyanate: 30-70 parts) that produce a polishing pad with controlled hardness (30-50 Shore D). This parameter optimization enables adequate material removal efficiency while preventing excessive surface roughness reduction that leads to pad glazing
Solution Approach 2:
The patent introduces dynamic compliance to the polishing pad through controlled pore structures and elastic material composition. The pad can dynamically adjust its surface properties during polishing, maintaining appropriate surface roughness reduction rate while preserving material removal efficiency, thereby preventing 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 effectively minimizes surface defects and maintains a consistent polishing rate by controlling surface roughness and elasticity, resulting in improved mechanical properties and reduced defects on semiconductor substrates.
Implementation Method 1
a molded polishing layer that comprises a polyurethane reaction product, wherein the curing agent comprises a tertiary amine-based polyol
Implementation Method 2
the polishing layer comprises a cured product of a composition comprising a urethane-based prepolymer, a curing agent, and a foaming agent
Implementation Method 3
a cured product of a composition comprising a urethane-based prepolymer, a curing agent
Implementation Method 4
the polishing layer comprises a cured product of a composition comprising a urethane-based prepolymer, a curing agent, and a foaming agent
Implementation Method 5
A chemical mechanical planarization (CMP) or chemical mechanical polishing (CMP) process may be carried out for various purposes in various technical fields
Data Source
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Figure 5(a)~6
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.