Resist Stripping Chemistry for Stable High-Aspect-Ratio 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 to larger areas, 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 an aprotic and protic solvent combination, 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 metal patterns with high aspect ratio tilt or collapse during the stripping process
Solution Approach 1:
The patent changes the chemical parameters of the stripping solution by using a non-dimethyl sulfoxide solvent combined with an alkaline compound, which modifies the stripping mechanism to prevent metal pattern collapse while maintaining effective resist removal
Solution Approach 2:
The alkaline compound acts as an intermediary that mediates between the solvent and the resist layer, enabling controlled stripping that preserves the structural integrity of high aspect ratio metal patterns
2Productivity
If the density of I/O pads is increased on semiconductor dies, then more functions can be integrated, but the packaging becomes more difficult and yield reduces
Solution Approach 1:
The patent uses conductive through vias to redistribute I/O pads from the die surface to the package substrate, effectively moving connections to another dimension and enabling higher pad density on the die while maintaining packaging quality
3Manufacturing precision
If high aspect ratio metal patterns are formed to achieve high distribution density, then more I/O pads can be redistributed, but the patterns tend to tilt or collapse during stripping
Solution Approach 1:
The patent modifies the chemical parameters of the stripping solution to create a gentler stripping action that can handle high aspect ratio metal patterns without causing them to tilt or collapse, enabling higher distribution density
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 of metal patterns and conductive through vias, enhancing the manufacturing yield and quality of the package structure by preventing tilting or collapse during the stripping process, thereby improving the packaging efficiency and reliability.
Implementation Method 1
A stripping solution is applied to the patterned resist layer to dissolve the patterned resist layer without dissolving the material layer
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.