Wafer Dicing Formulation for Offcut and Adhesive Removal
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Solution Overview
Problem
Current dicing processes using pure water are inefficient in removing dicing offcuts and adhesive residue from wafer surfaces, leading to contamination and increased defective devices, especially for image sensors, and result in high water consumption and costs.
Innovation Solution
A dicing formulation comprising 1.0 to 1.5% partially saponified polyvinyl alcohol and 0.4 to 0.6% polyoxyethylene-polyoxypropylene glycol ether, with optional phenyl glycol, diluted 10,000 to 100,000 times with pure water, is applied during the dicing process to effectively remove offcuts and adhesive residue, reducing contamination and enabling water reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pure water is used as the processing solution, then water consumption is high and cost is high, but the removal of dicing offcuts and adhesive residue is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the processing solution by adding specific polymers (polyvinyl pyrrolidone and vinyl acetate copolymer) with controlled molecular weights and ratios. This chemical parameter modification enables effective removal of adhesive residue without requiring large amounts of water, thus resolving the contradiction between water consumption and removal efficiency
Solution Approach 2:
The patent creates a composite processing solution by combining multiple components: water, polyvinyl pyrrolidone, and vinyl acetate copolymer in specific ratios. This composite formulation synergistically improves the removal of both dicing offcuts and adhesive residue while reducing water consumption compared to using pure water alone
2Manufacturing precision
If a polymer-based processing solution is used to improve offcut removal, then offcut removal efficiency is improved, but adhesive residue remains on the devices
Solution Approach 1:
The patent modifies the chemical parameters of the processing solution by incorporating vinyl acetate copolymer with specific molecular weight (40,000-160,000) and controlling its ratio (30-70 mass %) relative to polyvinyl pyrrolidone. This parameter optimization enables the solution to effectively remove both dicing offcuts and adhesive residue simultaneously, eliminating the harmful effect of adhesive contamination while maintaining offcut removal efficiency
3Productivity
If high speed blade dicing is used, then productivity is improved, but frictional resistance and heat generation increase
Solution Approach 1:
The patent introduces a specially formulated processing solution as an intermediary substance between the dicing blade and the wafer. This solution contains polymers that reduce frictional resistance during high-speed cutting, enabling faster dicing speeds while minimizing the harmful effects of friction and heat generation
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 formulation achieves clear wafer surfaces, reduces defective products, and allows for efficient wastewater treatment by effectively removing dicing offcuts and adhesive residue, even at high dilution ratios, thereby improving yield and conserving water.
Implementation Method 1
allowing a processing solution to flow in the region between the wafer and a rotating dicing blade to cool the part to be cut
Implementation Method 2
it becomes possible to more efficiently remove splintered dicing offcuts of the wafer
Implementation Method 3
During the dicing process, it is necessary to wash away and remove offcuts generated by dicing
Data Source
AI summary
A formulation for a wafer dicing process comprises 1.0 to 1.5 mass % of a partially saponified polyvinyl alcohol having a polymerization degree of 200 to 400 and a saponification degree of 75 to 85 mol %; 0.4 to 0.6 mass % of polyoxyethylene-polyoxypropylene glycol ether having a number average molecular weight of 10,000 to 20,000 with a polymerization ratio of polyoxyethylene to polyoxypropylene of 75:25 to 85:15; and pure water (all mass % based on 100 mass % of formulation). The formulation is used in the form of a processing solution obtained by diluting it 10,000 to 100,000 times by pure water and flowing it on a dicing blade in a wafer dicing process to effectively remove dicing offcuts from the wafer and minute pieces of adhesive released from an adhesive layer of a dicing tape.