Dicing Solution for Semiconductor Wafer Corrosion and Residue
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Solution Overview
Problem
During the dicing process of semiconductor wafers, contaminant residues and corrosion on bonding pads and metallization areas pose challenges, leading to poor bonding performance and potential device failure, especially with increasing wafer sizes and reduced die sizes prolonging dicing time.
Innovation Solution
A dicing solution comprising organic acids or their salts, surfactants, and a base in deionized water with a pH greater than 4, which is applied during the dicing process to inhibit residue adherence and corrosion, featuring low resistivity for charge dissipation, reduced surface tension for improved particle removal, and minimal foam generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If high purity deionized water is used as coolant during dicing, then corrosion is reduced, but silicon residue particles accumulate on bonding pads due to static charge buildup
Solution Approach 1:
The patent changes the chemical parameters of the coolant by adding specific compounds (ammonium fluorosulfonate, tetramethylammonium hydroxide, and surfactant) to deionized water, creating a solution with controlled pH (8.5-10.5) and specific conductivity (5-50 μS/cm) that prevents both corrosion and particle accumulation
Solution Approach 2:
The patent introduces intermediary substances (ammonium fluorosulfonate as corrosion inhibitor, tetramethylammonium hydroxide as pH buffer, and surfactant for particle removal) that mediate between the cutting process and the wafer surface, preventing harmful interactions
2Temperature
If deionized water floods the cutting area to flush away silicon particles, then cooling is improved, but particles are not completely removed and static charge builds up
Solution Approach 1:
The patent modifies the physical parameters of the coolant by adjusting conductivity to 5-50 μS/cm through additive formulation, enabling the solution to dissipate static charge while maintaining cooling effectiveness during the dicing process
Solution Approach 2:
The patent replaces the purely mechanical flushing action with a chemically enhanced solution that actively removes particles through surfactant action and dissipates static charge through controlled conductivity, supplementing mechanical cooling with chemical mechanisms
3Productivity
If dicing time is prolonged due to increased wafer size and reduced die size, then more particles accumulate and corrosion increases, but productivity requirements demand longer processing
Solution Approach 1:
The patent ensures continuous protection throughout the extended dicing process by formulating a stable solution that maintains consistent pH (8.5-10.5), conductivity (5-50 μS/cm), and protective properties throughout prolonged processing, preventing particle accumulation and corrosion over extended time periods
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 solution effectively prevents residue adherence and corrosion, enhances particle removal, and maintains the integrity of bonding pads, ensuring reliable wirebonding and assembly operations by minimizing kerf width, chip, and burr size, while maintaining the cleanliness of copper surfaces.
Implementation Method 1
The solution having a pH greater than 4... featuring low resistivity for charge dissipation
Implementation Method 2
at least one second compound selected from the group consisting of a surfactant and a base... reduced surface tension for improved particle removal
Implementation Method 3
at least one first compound selected from the group consisting of an organic acid and salt thereof; at least one second compound selected from the group consisting of a surfactant and a base... the solution having a pH greater than 4... inhibiting adherence of contamination residues and corrosion of the exposed metallization areas
Data Source
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AI summary
A solution for semiconductor wafer dicing is disclosed. The solution suppresses the adherence of contamination residues or particles, and reduces or eliminates the corrosion of the exposed metallization areas, during the process of dicing a wafer by sawing. The solution comprises at least one organic acid and/or salt thereof; at least a surfactant and/or at least a base; and deionized water. The composition has a pH greater than 4. The solution can further comprise a chelating agent, a defoaming agent, or a dispersing agent.