Silicon CMP Slurry pH Control to Reduce Surface Defects
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Solution Overview
Problem
The existing Chemical Mechanical Polishing (CMP) techniques for semiconductor substrates are inadequate in reducing defects on the surface of silicon materials, as described in JP 2002-114967 A.
Innovation Solution
A polishing method using a composition containing abrasive grains, a tri- or more polyvalent hydroxy compound, and a dispersing medium with a pH of less than 6.0, which reduces adhesion of organic residues and thereby minimizes surface defects during the polishing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP techniques are used, then polishing can be performed on semiconductor substrates, but surface defects such as scratches and residue adhesion are not sufficiently reduced
Solution Approach 1:
The invention changes the chemical parameters of the polishing composition by specifying a pH range of 2.0 to 6.0 and incorporating tri- or more polyvalent hydroxy compounds with specific molecular weights (90 or more). These parameter changes transform the chemical environment to reduce organic residue adhesion and minimize surface defects during polishing of silicon materials
Solution Approach 2:
The invention creates a composite polishing composition that integrates multiple functional components: abrasive grains for mechanical removal, tri- or more polyvalent hydroxy compounds for chemical etching and surface modification, and dispersing media for stable suspension. This composite formulation synergistically reduces surface defects while maintaining polishing effectiveness
2Productivity
If polishing composition is used to remove material, then planarization is achieved, but organic residues adhere to the surface causing defects
Solution Approach 1:
The invention converts the harmful adhesion of organic residues into a beneficial effect by using tri- or more polyvalent hydroxy compounds that chemically interact with and modify the residue molecules. The hydroxy groups form hydrogen bonds or chemical complexes with organic residues, preventing their adhesion to the silicon surface and transforming them into removable byproducts
Solution Approach 2:
By controlling the pH within 2.0 to 6.0 and selecting hydroxy compounds with molecular weights of 90 or more, the invention optimizes the chemical environment to prevent organic residue adhesion while maintaining efficient material removal, thus achieving both high productivity and clean surfaces
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 method effectively reduces surface defects on silicon materials by utilizing the hydrophilizing properties of the polyvalent hydroxy compound, improving the polishing efficiency and reducing scratches and residue adhesion.
Implementation Method 1
it was found that the above effect was obtained by a polishing method, including polishing a polishing object containing a silicon material by using a polishing composition containing abrasive grains, a tri- or more polyvalent hydroxy compound and a dispersing medium and having pH of less than 6.0
Data Source
AI summary
A polishing method according to the present invention, includes polishing a polishing object containing a silicon material by using a polishing composition containing abrasive grains, a tri- or more polyvalent hydroxy compound and a dispersing medium and having pH of less than 6.0.