CMP Polishing Composition for High-Rate Polymeric Material Removal
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Solution Overview
Problem
Current CMP slurries are ineffective in polishing polymeric materials used in advanced semiconductor packaging applications, as they were designed for older chip designs and do not perform well with modern polymer-based materials.
Innovation Solution
A polishing composition comprising at least one abrasive, a polymer removal enhancer of the formula X4P+N−, and a solvent, along with optional cationic surfactants and azole-containing corrosion inhibitors, is applied to the substrate to efficiently remove polymeric materials while maintaining surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If currently available CMP slurries designed for older chip designs are used, then the polishing process can be maintained with existing formulations, but the removal rate of polymeric materials used in advanced packaging applications is insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating specific polymer removal enhancers (quaternary ammonium compounds and phosphonium compounds) alongside traditional abrasive components. This parameter change transforms the slurry's chemical properties to specifically target polymeric materials, achieving removal rates exceeding 750 Å/min while maintaining effective polishing performance on advanced packaging materials
Solution Approach 2:
The invention creates a composite polishing formulation that combines multiple functional components: abrasive particles for mechanical removal, polymer removal enhancers (quaternary ammonium compounds like tetrapropylammonium hydroxide or phosphonium compounds like tetrakis(hydroxymethyl)phosphonium sulfate) for chemical enhancement, and corrosion inhibitors (azole compounds like benzotriazole) for protection. This composite approach synergistically addresses both the high removal rate requirement and the reliability of polishing on polymeric substrates
2Productivity
If high removal rate is achieved through aggressive polishing, then productivity increases, but surface defects and corrosion increase
Solution Approach 1:
The patent converts potentially harmful corrosion effects into beneficial outcomes by incorporating corrosion inhibitors (azole compounds such as benzotriazole, tolyltriazole, or methyl benzotriazole) that actively prevent metal substrate degradation during the aggressive polishing process. This allows the use of high removal rate formulations without sacrificing substrate integrity, transforming what would be a harmful side effect into a controlled and protected process
Solution Approach 2:
The polymer removal enhancers act as intermediary agents that facilitate selective removal of polymeric materials while protecting the underlying metal substrate. These compounds (quaternary ammonium or phosphonium compounds) mediate between the abrasive particles and the polymer substrate, enabling high removal rates through enhanced chemical-mechanical interaction while the corrosion inhibitors simultaneously mediate protection at the metal-substrate interface
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 composition achieves a high polymeric material removal rate, exceeding 750 Å/min, with a smooth surface finish suitable for further processing, and minimizes defects and corrosion.
Implementation Method 1
Chemical mechanical polishing (CMP) is a process used to planarize/flatten a wafer surface by removing material using abrasion-based physical processes
Implementation Method 2
removing material using abrasion-based physical processes concurrently with surface-based chemical reactions
Implementation Method 3
contacting the wafer surface with a polishing pad and moving the polishing pad in relation to the wafer
Data Source
AI summary
This disclosure relates to polishing compositions containing at least one abrasive, at least one polymer removal enhancer, and at least one solvent. The polishing compositions of this disclosure may optionally include at least one of a cationic surfactant, an azole-containing corrosion inhibitor, or a nonionic surfactant. The polishing compositions of this disclosure may polish a polymeric substrate at a rate of at least about 200 Å/min.