Polishing composition, polishing method, and method of producing semiconductor substrate
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Solution Overview
Problem
The existing chemical mechanical polishing (CMP) techniques for semiconductor substrates have insufficient polishing speed and are prone to scratches due to the limitations in the form and distribution of abrasive grains used in the polishing compositions.
Innovation Solution
A polishing composition containing spherical abrasive grains with a negative zeta potential, an aspect ratio of 1.1 or less, and a wide particle size distribution, combined with an anionic water-soluble polymer and an alkali metal salt basic inorganic compound, which enhances the mechanical and chemical polishing action, improving the polishing speed and reducing scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional abrasive grains are used in CMP, then polishing can be performed, but the polishing speed is insufficient
Solution Approach 1:
The patent changes the physical and chemical parameters of abrasive grains by controlling their shape (aspect ratio ≤1.1), surface charge (negative zeta potential), and size distribution (D90/D50 >1.3). These parameter changes enable the abrasive grains to achieve both high polishing speed and good surface quality simultaneously, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent creates a composite polishing system combining specifically designed abrasive grains with an anionic water-soluble polymer and basic inorganic compound. This composite composition works synergistically to achieve high polishing speed while maintaining surface quality, addressing the contradiction between productivity and reliability.
2Productivity
If polishing is performed to increase speed, then productivity improves, but scratches occur on the surface
Solution Approach 1:
The patent modifies the aspect ratio parameter of abrasive grains to be ≤1.1 (nearly spherical), which prevents scratching while maintaining high polishing speed. The controlled particle size distribution (D90/D50 >1.3) ensures uniform material removal without creating surface defects, thus resolving the contradiction between productivity and harmful surface effects.
Solution Approach 2:
The patent converts the potential harm of abrasive grains causing scratches into a benefit by precisely controlling their shape and size distribution. The nearly spherical shape and controlled size range transform what could be harmful irregular particles into beneficial polishing agents that remove material efficiently without creating surface defects.
3Productivity
If abrasive grain distribution is not optimized, then composition is simpler, but polishing efficiency is low
Solution Approach 1:
The patent optimizes the particle size distribution parameter by specifying D90/D50 >1.3, which creates an effective size distribution for polishing without requiring complex multi-component formulations. This single parameter control achieves high polishing efficiency while keeping the composition relatively simple, resolving the contradiction between productivity and device complexity.
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 proposed composition significantly increases the polishing speed while maintaining surface quality by ensuring efficient rolling and distribution of abrasive grains, reducing the occurrence of scratches and improving the overall polishing efficiency.
Implementation Method 1
a zeta potential of the abrasive grains is negative
Implementation Method 2
chemical mechanical polishing (CMP) technique for physically polishing and flattening a semiconductor substrate
Data Source
AI summary
A polishing composition according to the present invention contains abrasive grains, a basic inorganic compound, an anionic water-soluble polymer, and a dispersing medium, in which a zeta potential of the abrasive grains is negative, an aspect ratio of the abrasive grains is 1.1 or less, in a particle size distribution of the abrasive grains obtained by a laser diffraction/scattering method, a ratio D90/D50 of a particle diameter D90 when an integrated particle mass reaches 90% of a total particle mass from a fine particle side to a particle diameter D50 when the integrated particle mass reaches 50% of the total particle mass from the fine particle side is more than 1.3, and the basic inorganic compound is an alkali metal salt.