Polishing Foam Retention for CMP Slurry Wastage
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Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) slurries are inefficient due to low viscosity, leading to wastage as they are easily discharged from the polishing pad, resulting in suboptimal utilization and increased costs.
Innovation Solution
The use of polishing foam generated from an aqueous dispersion containing abrasive grains and a foam forming and retaining agent, which is applied to a specific region of the polishing pad, allowing for effective retention and utilization, reducing wastage and enhancing polishing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional CMP slurry is used, then polishing can be performed, but the slurry is easily discharged from the polishing pad due to low viscosity, resulting in poor utilization efficiency
Solution Approach 1:
The patent changes the physical state parameter of the CMP slurry from liquid to foam by introducing a foaming agent. This parameter change increases the viscosity and retention capability of the polishing medium on the polishing pad, preventing discharge and improving utilization efficiency while maintaining polishing functionality
Solution Approach 2:
The patent creates a composite material by combining CMP slurry with a foaming agent to form polishing foam. This composite structure allows the polishing medium to retain its abrasive properties while gaining foam characteristics such as higher viscosity and better adhesion to the polishing pad surface, reducing wastage
2Productivity
If CMP slurry is fed to the polishing pad, then polishing action is achieved, but part of the slurry is discharged outside the polishing pad, reducing utilization efficiency
Solution Approach 1:
The patent transforms the CMP slurry into foam form, changing its physical parameters including viscosity and surface tension. This allows the polishing medium to remain on the polishing pad surface during the polishing process, preventing discharge while maintaining the necessary polishing action and improving productivity
3Quantity of substance
If polishing foam is used instead of conventional slurry, then slurry retention on polishing pad is improved, but additional foam forming components are required
Solution Approach 1:
The patent introduces a foaming agent as an intermediary substance that transforms conventional CMP slurry into polishing foam. This intermediary component enables the slurry to be retained on the polishing pad as foam while maintaining the original abrasive particles and chemical composition, thus improving utilization efficiency without significantly complicating the overall system
Solution Approach 2:
The patent modifies the physical state of the CMP slurry by adding a foaming agent, changing it from liquid to foam form. This parameter change improves retention on the polishing pad and utilization efficiency, while the foam forming mechanism is simple enough that it does not significantly increase device or process 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 polishing foam maintains its volume and effectively polishes the semiconductor film with improved efficiency, reducing wastage and maintaining practical polishing speeds even with reduced slurry quantities, thus enhancing the utilization efficiency of the CMP process.
Implementation Method 1
The polishing foam can be obtained by turning the aqueous dispersion into a foamy body. The aqueous dispersion includes 0.01-20% by mass of abrasive grain and 0.01-1% by mass of foam forming and retaining agent
Implementation Method 2
The CMP slurry thus fed spreads to the outer peripheral region of the polishing pad by centrifugal force, thereby the CMP slurry is utilized for the polishing of a film which is being contacted with the polishing pad
Data Source
AI summary
According to one embodiment, the method of manufacturing a semiconductor device includes contacting a film formed on a semiconductor substrate with a rotating polishing pad which is supported on a turntable, and feeding polishing foam to a region of the polishing pad with which the film is contacted, thereby polishing the film. The polishing foam is obtained by turning the aqueous dispersion into a foamy body. The aqueous dispersion includes 0.01-20% by mass of abrasive grain and 0.01-1% by mass of foam forming and retaining agent, all based on a total mass of the aqueous dispersion.