Polishing Composition for HLM Bump Cancellation and Removal Rate
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Solution Overview
Problem
Conventional polishing compositions for silicon wafers fail to achieve both high polishing removal rate and effective bump cancellation at the periphery of hard laser marks (HLM), leading to reduced yield due to unpolished stressed layers transforming into bumps.
Innovation Solution
A polishing composition comprising an abrasive, a basic compound, a pH buffering agent, and water, with specific ratios and types of salts (S_L and S_H) maintaining a pH of 9.0 or higher, achieving both high polishing removal rate and excellent bump cancellation ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing compositions are used, then polishing capability is provided, but they cause scratching, hazing, and streaking that require rework
Solution Approach 1:
The patent changes the chemical parameters of the polishing composition by using specific pH ranges (pH 2-4 for acid-based, pH 8-10 for base-based), controlling water content (5-50%), and selecting specific alcohol types and concentrations. These parameter changes enable the composition to achieve high polishing quality without causing scratching or hazing, resolving the technical contradiction between polishing capability and harmful effects.
Solution Approach 2:
The patent creates a composite polishing composition by combining multiple components: water, alcohol (methanol, ethanol, or isopropanol), acid or base agents, and specific concentration ratios. This composite approach allows the composition to provide effective polishing while minimizing harmful effects like scratching and streaking, thereby improving polishing quality without generating harmful factors.
2Manufacturing precision
If multiple polishing steps are used to achieve high quality, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent segments the polishing process into two distinct composition types (acid-based for initial polishing and base-based for final finishing), each optimized for specific stages. This segmentation allows each step to be highly effective, reducing the number of iterations needed and improving overall productivity while maintaining high optical quality.
Solution Approach 2:
The patent uses parameter changes in pH and composition to optimize each polishing step for its specific function. The acid-based composition (pH 2-4) is optimized for removing defects efficiently, while the base-based composition (pH 8-10) is optimized for achieving high-quality finish. This parameter optimization reduces the number of polishing steps required, thereby improving productivity without sacrificing manufacturing precision.
3Productivity
If traditional polishing compositions are used, then polishing action is achieved, but environmental harm and health risks increase
Solution Approach 1:
The patent changes the chemical parameters by严格控制 pH ranges (pH 2-4 for acid-based, pH 8-10 for base-based), controlling water content (5-50%), and selecting specific alcohol types. These parameter changes enable the composition to maintain polishing efficiency while reducing environmental and health hazards associated with traditional polishing compositions.
Solution Approach 2:
The patent uses alcohol-based compositions (methanol, ethanol, or isopropanol) that provide a safer, more environmentally friendly alternative to traditional polishing compositions. These alcohol-based formulations reduce harmful emissions and health risks while maintaining effective polishing action, thereby resolving the contradiction between productivity and harmful factors.
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 composition effectively cancels bumps at the periphery of HLM while maintaining a high polishing removal rate, improving polishing efficiency and yield.
Implementation Method 1
alcohol which facilitates controlled evaporation
Implementation Method 2
acid or base components in specific concentrations that facilitate polishing action
Data Source
AI summary
Provided is a polishing composition that can achieve both high polishing removal rate and excellent bump cancellation ability at the periphery of HLM. The polishing composition contains an abrasive, a basic compound, a pH buffering agent, and water, wherein the pH buffering agent contains a salt SL having at least one of acid dissociation constant (pKa) values in a range of 9 to 11 and a salt SH having at least one of pKa values of 12 or more.