Polishing Composition with Water-Soluble Polymer for Polysilicon CMP
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Solution Overview
Problem
The challenge in semiconductor manufacturing is controlling the polishing removal rate of polysilicon and reducing defects on its surface during chemical mechanical polishing (CMP), as polysilicon and silicon oxide are soft and easily react with polishing agents, making it difficult to achieve the desired surface quality.
Innovation Solution
A polishing composition containing abrasive grains and a polishing removal rate inhibitor, where the inhibitor is a water-soluble polymer with specific molecular weight and structural characteristics, is used to reduce the polishing removal rate of polysilicon and minimize surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing agents are used, then polishing can proceed, but the polishing removal rate of polysilicon is too high and defects occur on the surface
Solution Approach 1:
The patent introduces a water-soluble polymer as an intermediary substance that specifically adsorbs to polysilicon surfaces during CMP. This polymer acts as a mediator between the polishing slurry and polysilicon, forming a protective layer that reduces excessive material removal and prevents surface defects while allowing controlled polishing to proceed
Solution Approach 2:
The patent modifies the chemical composition parameters of the polishing slurry by incorporating a water-soluble polymer with specific molecular weight (1,000-10,000) and functional groups. This parameter change transforms the polishing chemistry to selectively inhibit polysilicon removal rate while maintaining effectiveness on other materials like silicon oxide
2Manufacturing precision
If polishing is performed to achieve flatness, then surface smoothness improves, but defects and residues remain on polysilicon surface
Solution Approach 1:
The water-soluble polymer serves as a protective intermediary during the polishing process, forming a controllable layer on polysilicon that prevents direct aggressive interaction between abrasive particles and the polysilicon surface, thereby reducing defect formation while maintaining flatness
Solution Approach 2:
The patent converts the naturally high reactivity of polysilicon with polishing agents, which causes excessive removal and defects, into a beneficial effect by using the water-soluble polymer to control and moderate this reactivity, transforming the harmful high removal rate into a controlled, defect-free polishing process
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 reduces the polishing removal rate of polysilicon and minimizes defects on its surface, enhancing the surface quality of polished wafers.
Implementation Method 1
a polishing removal rate inhibitor that reduces a polishing removal rate of polysilicon
Implementation Method 2
The mechanical action is usually allowed to proceed with a polishing pad mounted on a table and pressed toward the surface to be polished
Implementation Method 3
CMP utilizes chemical and mechanical interaction to achieve flatness of the surface to be polished
Data Source
AI summary
An object is to provide a polishing composition capable of reducing a polishing removal rate of polysilicon. An object is to provide a means capable of reducing a polishing removal rate of polysilicon and further reducing defects on a surface of polysilicon after polishing. A polishing composition contains abrasive grains and a polishing removal rate inhibitor that reduces a polishing removal rate of polysilicon, and the polishing removal rate inhibitor is a water-soluble polymer meeting all requirements below: 1) a number average molecular weight is 200 or more and 600 or less; 2) a compound having a repeating unit formed of AO in which A is an alkylene group and O is an oxygen atom is contained; and 3) a compound having a special repeating unit in which two oxygen atoms are further added to the repeating unit is contained in an amount of more than 0 mass % and less than 0.1 mass % with respect to the entire water-soluble polymer.