Polyimide Etch Mask for Semiconductor Passivation Cracking
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Solution Overview
Problem
Existing semiconductor packaging structures, including redistribution layers and passivation layers, often suffer from metal cracking issues during testing and packaging, leading to packaging defects and reliability concerns due to non-uniform metal distribution and dimensions in capacitors.
Innovation Solution
A method involving the formation of a polyimide layer with enhanced mechanical characteristics, such as tensile strength and Young's modulus, is used as an etch mask to pattern the passivation layer, eliminating additional lithography steps and reducing overlay shifts, thereby addressing cracking issues and improving manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional passivation layers and redistribution layers are used in semiconductor packaging, then the basic packaging function is achieved, but metal cracking issues occur during testing and packaging due to non-uniform metal distribution and dimensions in capacitors
Solution Approach 1:
The patent modifies the mechanical properties of the polyimide layer by adjusting its composition (including more than 50% aliphatic amide or Gamma-Butyrolactone) to achieve enhanced tensile strength and Young's modulus. This parameter change allows the polyimide layer to better accommodate stress and prevent metal cracking in the capacitor structures during packaging and testing.
2Manufacturing precision
If additional lithography steps are used to pattern the passivation layer, then precise patterning is achieved, but manufacturing cost increases and throughput decreases
Solution Approach 1:
The patent combines the patterning function into the polyimide layer formation step itself. The polyimide layer is patterned concurrently with its deposition, eliminating the need for separate lithography steps to pattern the passivation layer. This merging of operations maintains patterning precision while significantly improving manufacturing throughput and reducing costs.
Solution Approach 2:
The polyimide layer serves multiple functions: it acts as both the passivation layer and the etch mask for patterning. This multi-functionality eliminates the need for additional dedicated patterning steps, thereby increasing productivity while maintaining the required manufacturing precision through the inherent properties of the polyimide material.
3Manufacturing precision
If additional lithography steps are used to pattern the passivation layer, then precise patterning is achieved, but manufacturing cost increases due to process complexity
Solution Approach 1:
The patent merges the patterning operation into the polyimide layer formation process. By patternning the polyimide layer concurrently with its deposition, the invention eliminates separate lithography steps, thereby reducing manufacturing complexity and cost while maintaining the required patterning precision through the polyimide's inherent properties.
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 reduces manufacturing costs, increases throughput, and enhances the mechanical strength of the polyimide layer, resulting in improved reliability and reduced defects in the semiconductor packaging process.
Implementation Method 1
The polyimide layer is patterned and used as an etch mask to pattern the passivation layer
Data Source
AI summary
The present disclosure provides a method that includes providing an integrated circuit (IC) substrate having various devices and an interconnection structure that couples the devices to an integrated circuit; forming a first passivation layer on the IC substrate; forming a redistribution layer on the first passivation layer, the redistribution layer being electrically connected to the interconnection structure; forming a second passivation layer on the redistribution layer and the first passivation layer; forming a polyimide layer on the second passivation layer; patterning the polyimide layer, resulting in a polyimide opening in the polyimide layer; and etching the second passivation layer through the polyimide opening using the polyimide layer as an etch mask.