CMP Pad Composition for High-Rate Low-Scratch Insulating Film Polishing
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) methods face a trade-off between suppressing polishing scratches and maintaining a high polishing rate or selection ratio of insulating films, making it difficult to achieve both simultaneously.
Innovation Solution
A polishing method using a polishing pad with a polyurethane resin layer containing methylene diphenyl diisocyanate (MDI) and abrasive particles like ceria, combined with a specific pH and dispersant, to enhance polishing efficiency while minimizing scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the polishing rate or selection ratio of an insulating film is increased, then productivity is improved, but polishing scratches are generated more frequently
Solution Approach 1:
The patent changes the chemical parameters of the polishing agent by specifying pH ranges (8.0-10.0) and using specific dispersants to control the chemical reactivity toward silicon oxide, enabling high polishing rates without excessive mechanical action that causes scratches
Solution Approach 2:
The patent uses composite abrasive particles consisting of ceria core with silica shell, combining the high reactivity of ceria for fast polishing with the gentle surface interaction of silica that reduces scratch formation
2Productivity
If a hard polishing pad is used to increase polishing rate, then productivity is improved, but polishing scratches are generated more frequently
Solution Approach 1:
The patent specifies Shore A hardness ranges for the polishing pad (60-90 degrees) and adjusts the density and porosity parameters to achieve optimal balance between polishing rate and scratch suppression
Solution Approach 2:
The patent employs porous polishing pads with controlled pore structures that allow polishing agent penetration and provide mechanical cushioning, reducing direct hard contact between pad and wafer surface while maintaining polishing efficiency
3Object-affected harmful factors
If a soft polishing pad is used to suppress polishing scratches, then scratch generation is reduced, but polishing rate decreases
Solution Approach 1:
The patent introduces chemical intermediaries (dispersants and pH-adjusted polishing agents) that mediate between the polishing pad and insulating film, enabling chemical assistance to the mechanical polishing process to maintain high rates with softer pads
Solution Approach 2:
The patent modifies the chemical composition parameters of the polishing agent including pH, ionic strength, and surfactant concentration to enhance chemical reactivity, compensating for the reduced mechanical action from softer pads
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 method effectively suppresses polishing scratches while maintaining a high polishing rate and selection ratio, improving the productivity of semiconductor components.
Implementation Method 1
polishing through relative motion thereof
Implementation Method 2
chemical mechanical polishing method (hereinafter, referred to as CMP)
Implementation Method 3
the polishing layer has a water absorption coefficient of 5% or more
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
To provide a polishing method in which the generation of polishing scratches can be sufficiently suppressed while a sufficiently high polishing rate or selection ratio of an insulating film is maintained and a method for producing a semiconductor component using the polishing method. A polishing method including bringing a surface to be polished into contact with a polishing pad while supplying a polishing agent to perform polishing through relative motion thereof, in which the polishing agent contains an abrasive particle and water, the polishing pad has a polishing layer containing a polyurethane resin, the polyurethane resin includes a constitution unit derived from methylene diphenyl diisocyanate (MDI), a content of the methylene diphenyl diisocyanate is 30 mass% or more based on a total mass of the polishing layer, the polishing layer has a shore A hardness of 90 degrees or less, the polishing layer has a water absorption coefficient of 5% or more, and the surface to be polished includes an insulating film.