Dummy Patterns for Resist Uniformity in Vacuum Lamination
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Solution Overview
Problem
In the vacuum lamination process for semiconductor and electronic substrates, the accumulation of insulative organic material (dry film resist) at the peripheral region leads to swelling, resulting in defective device elements due to uneven thickness, which affects soldering performance and increases the number of defective devices.
Innovation Solution
A method involving the formation of dummy patterns, such as plating patterns or through-holes, between the peripheral ring electrode and device elements to redistribute the resist and maintain uniform thickness, thereby reducing swelling and ensuring consistent coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum lamination is performed without dummy patterns, then the lamination process is simple and fast, but resist accumulates at peripheral regions causing swelling and defective device elements
Solution Approach 1:
Dummy patterns are formed on the substrate before the vacuum lamination process to pre-establish regions that will attract and distribute the resist material. This preliminary preparation ensures that when the resist is applied, it naturally flows into the dummy patterns, preventing peripheral accumulation and swelling without requiring complex real-time control during lamination.
Solution Approach 2:
The dummy patterns act as intermediary structures between the peripheral ring electrode and the device elements. These intermediate features serve as sacrificial elements that absorb excess resist material, mediating the distribution of resist across the substrate surface and preventing direct contact between accumulated resist and critical device regions.
2Reliability
If the peripheral ring electrode is made larger, then it provides better electrical contact, but it increases resist accumulation and swelling in the peripheral region
Solution Approach 1:
The peripheral region is segmented into functional zones by introducing dummy patterns. These patterns create distinct regions: the peripheral ring electrode area for electrical contact, the dummy pattern areas for resist absorption, and the device element areas for functional operation. This segmentation allows each zone to optimize its function without interfering with others.
Solution Approach 2:
Different regions of the substrate are given different local properties through the dummy patterns. The peripheral region near the electrode has dummy patterns with specific geometries optimized for electrical contact, while dummy patterns closer to device elements have geometries optimized for resist distribution. This local differentiation allows simultaneous optimization of electrical contact and resist uniformity.
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 dummy patterns effectively suppress resist accumulation, reducing the elevation of the resist at peripheral regions, improving the reliability of device elements by maintaining uniform thickness and enhancing soldering performance.
Implementation Method 1
a chamber capable of producing a vacuum environment in the chamber by evacuation
Implementation Method 2
a membrane that can be heated and expands by regulating a pressure
Data Source
AI summary
A method of forming an insulative film includes a step of vacuum laminating an insulative organic material on a substrate that has a peripheral ring electrode formed in a peripheral region of the substrate and a device element(s) formed inside the peripheral region, and has a surface configuration including raised parts. A first dummy pattern is formed in a region between the peripheral ring electrode and the device element on the substrate.