Polishing Agent for Semiconductor CMP Selectivity and Flatness
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Solution Overview
Problem
In CMP processes for semiconductor elements, there is a need for a polishing agent that improves polishing selectivity for insulating materials with respect to stopper materials to minimize erosion and achieve high flatness, while reducing polishing scratches and dishing.
Innovation Solution
A polishing agent comprising water, abrasive grains of hydroxide of a tetravalent metal element, polyalkylene glycol, and a cationic polymer, which enhances polishing selectivity and reduces scratches and dishing, even when using abrasive pads with low hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cerium oxide-based polishing agents are used to achieve high polishing rate, then polishing efficiency is improved, but polishing scratches are generated on the substrate surface
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing agent by using hydroxide of a tetravalent metal element instead of conventional cerium oxide, and by controlling pH within 3-12. This parameter change maintains high polishing rate while reducing mechanical action to minimize polishing scratches on the substrate surface.
Solution Approach 2:
The patent employs a composite polishing agent system combining hydroxide of a tetravalent metal element with specific organic additives (polyethylene glycol with molecular weight 200-10,000 and carboxylic acid or its salt). This composite formulation achieves both high polishing rate and reduced scratching by balancing chemical and mechanical actions.
2Manufacturing precision
If polishing selectivity for insulating material with respect to stopper material is increased to minimize erosion, then flatness is improved, but polishing rate may be reduced
Solution Approach 1:
The patent optimizes pH parameters within the range of 3-12 to enhance polishing selectivity between insulating material and stopper material. This parameter adjustment improves flatness by minimizing stopper material erosion while maintaining adequate polishing rate through the chemical activity of the tetravalent metal hydroxide.
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 agent effectively minimizes dishing and polishing scratches, achieving high flatness and improved polishing selectivity for insulating materials, particularly in CMP techniques for STI, pre-metal, and interlayer insulating materials.
Implementation Method 1
CMP (chemical mechanical polishing) technique
Implementation Method 2
abrasive grains containing a hydroxide of a tetravalent metal element
Implementation Method 3
at least one cationic polymer selected from the group consisting of allylamine polymers, diallylamine polymers, vinylamine polymers and ethyleneimine polymers
Data Source
AI summary
The polishing agent of the invention comprises water, an abrasive grain containing a hydroxide of a tetravalent metal element, polyalkylene glycol, and at least one cationic polymer selected from the group consisting of allylamine polymers, diallylamine polymers, vinylamine polymers and ethyleneimine polymers.