Semiconductor Spacer Frame Structure to Prevent Underfill Bleed
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Solution Overview
Problem
Conventional silicon spacers in semiconductor device assemblies are prone to delamination and cracking due to underfill material bleeding and mechanical stress, leading to electrical failures and increased fabrication costs from additional processing steps.
Innovation Solution
The use of frame structures made of solder resist or solder paste to restrain spacers, which are partially embedded within the frame, preventing underfill material bleed-out and providing mechanical support to semiconductor dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silicon spacers are used to support semiconductor dies, then mechanical support and adhesive holding are improved, but delamination and cracking occur due to underfill material bleeding and mechanical stress
Solution Approach 1:
The spacer is divided into two distinct parts: a frame structure made of solder resist material and a spacer body made of silicon. The frame structure provides mechanical support and restraint, while the silicon portion provides adhesive holding. This segmentation allows each material to perform its optimal function without the drawbacks of using a single material for both purposes.
Solution Approach 2:
The solder resist frame structure acts as an intermediary between the substrate and the silicon spacer body. It provides a restraining framework that prevents underfill material from bleeding under the silicon spacer, thereby preventing delamination and cracking while allowing the silicon to perform its adhesive function.
2Reliability
If additional substrate cleaning processes are applied to prevent residues, then spacer adhesion is improved, but fabrication complexity and cost increase
Solution Approach 1:
The solder resist frame structure is formed on the substrate before the silicon spacer is attached. This preliminary action creates a protective framework that prevents underfill material from bleeding under the spacer during subsequent assembly processes, eliminating the need for additional cleaning processes that would otherwise be required to ensure proper adhesion.
3Reliability
If frame structures are used to restrain spacers, then delamination and cracking are prevented, but device complexity increases
Solution Approach 1:
The frame structure and spacer body are combined into a single integrated component. The solder resist frame is formed first, then the silicon spacer body is attached within and restrained by the frame. This merging creates a unified structure that provides both mechanical support and adhesive holding functions while maintaining manufacturing simplicity through standard semiconductor fabrication processes.
Data Source
AI summary
A semiconductor device assembly including a substrate; a frame structure disposed on the substrate, the frame structure comprising peripheral walls defining an enclosed region; and a spacer disposed on the substrate within the enclosed region and restrained by the frame structure. A method of forming a semiconductor assembly, including forming a frame structure on a substrate, the frame structure comprising peripheral walls defining an enclosed region; attaching a semiconductor die to the substrate, the semiconductor die being adjacent to the frame structure; and dispensing a spacer on the substrate within the enclosed region, the spacer being restrained by the frame structure.