Resist Removal Chemistry for High-Density Through-Via Metal Patterns
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Solution Overview
Problem
The increasing density of I/O pads on semiconductor dies poses challenges in packaging, leading to yield reduction and inefficiencies in integrating functions due to the difficulty in redistributing pads effectively, especially with high aspect ratio metal patterns that tend to tilt or collapse during the stripping process.
Innovation Solution
A method involving the use of a stripping solution comprising a non-dimethyl sulfoxide solvent and an alkaline compound, with aprotic and protic solvents, to break down the patterned resist layer without dissolving the seed layer or metal patterns, allowing for the formation of conductive through vias with high aspect ratios and high distribution density without tilting or collapsing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional stripping solutions are used to remove the resist layer, then the resist layer can be removed, but the high aspect ratio metal patterns tilt or collapse during the stripping process
Solution Approach 1:
The patent modifies the chemical composition parameters of the stripping solution by replacing dimethyl sulfoxide with alternative solvents (cyclic carcarbonates, chain carcarbonates, or their mixtures with alcohols), and adjusts the pH range to 2-12, thereby changing the stripping mechanism to prevent metal pattern collapse while maintaining effective resist removal
Solution Approach 2:
The stripping solution is formulated as a composite system combining multiple solvent components (cyclic carcarbonates, chain carcarbonates, and/or alcohols) with controlled pH, creating a synergistic chemical environment that selectively removes resist without damaging the metal patterns
2Productivity
If the density of I/O pads on semiconductor dies is increased, then more functions can be integrated, but the packaging becomes more difficult and yield is reduced
Solution Approach 1:
The patent enables higher I/O pad density packaging by establishing a reliable stripping process that prevents metal pattern damage, thereby allowing more aggressive layout designs and finer pitch configurations without compromising manufacturing yield
3Manufacturing precision
If high aspect ratio metal patterns are formed to enable fine pitch routing, then integration density improves, but the metal patterns become prone to tilting or collapsing during stripping
Solution Approach 1:
The patent changes the chemical parameters of the stripping solution (solvent type, pH, composition ratios) to create a gentler stripping action that can effectively remove resist while providing sufficient support to prevent collapse of high aspect ratio metal patterns with fine pitch dimensions
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
This approach ensures the integrity and quality of the package structure by maintaining the metal patterns' integrity and improving the manufacturing yield of conductive through vias, enabling efficient redistribution and integration of semiconductor functions.
Implementation Method 1
A stripping solution is applied to the patterned resist layer to dissolve the patterned resist layer without dissolving the material layer
Implementation Method 2
the stripping solution comprises a non-dimethyl sulfoxide solvent and an alkaline compound
Data Source
AI summary
A method for removing a resist layer including the following steps is provided. A patterned resist layer on a material layer is formed. A stripping solution is applied to the patterned resist layer to dissolve the patterned resist layer without dissolving the material layer, wherein the stripping solution comprises a non-dimethyl sulfoxide solvent and an alkaline compound, the non-dimethyl sulfoxide solvent comprises an aprotic solvent and a protic solvent.