Fingerprint Chip Packaging with Protection Layer
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Solution Overview
Problem
Fingerprint sensing regions in fingerprint identification chips are not effectively protected during downstream fabrication and assembly processes, leading to potential damage and reduced yield rates.
Innovation Solution
A package structure for fingerprint identification chips that includes a film layer made of silicon dioxide and silicon nitride, a protection layer with a predetermined thickness, and a plastic package surrounding the chip, with a solder ball array for electrical connection, providing enhanced protection and a predefined fingerprint identification distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the fingerprint identification chip is thinned using TSV and trenching processes to reduce thickness, then the chip thickness is reduced, but the fingerprint sensing region becomes vulnerable to damage during downstream fabrication and assembly
Solution Approach 1:
A protection layer is formed over the fingerprint sensing region before downstream fabrication and assembly processes. This protection layer acts as a cushioning barrier that prevents damage to the thinned fingerprint sensing region during subsequent manufacturing steps, resolving the contradiction between chip thinning and vulnerability to damage.
Solution Approach 2:
The solution employs a composite structure combining the thinned fingerprint identification chip with a protection layer and packaging substrate. This composite structure allows the chip to maintain reduced thickness while the additional layers provide mechanical protection and structural support during fabrication and assembly processes.
2Reliability
If a protection layer is added to protect the fingerprint sensing region, then the protection and yield rate improve, but the chip thickness and volume increase
Solution Approach 1:
Instead of increasing protection in the vertical dimension (which would increase thickness), the solution extends protection to the horizontal dimension by using a packaging substrate that surrounds and supports the chip laterally. This allows effective protection without significantly increasing the chip's vertical thickness.
Solution Approach 2:
The packaging substrate acts as an intermediary structure that provides mechanical support and protection to the thinned fingerprint identification chip. This intermediary layer absorbs mechanical stresses and protects the sensing region during fabrication and assembly, allowing the chip itself to remain thin while still achieving reliable protection.
Data Source
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AI summary
The present application provides a fingerprint identification module and a package structure of a fingerprint identification chip. The fingerprint identification module includes: a fingerprint identification chip and a package structure for packaging the fingerprint identification chip. The package structure leaves a fingerprint sensing region of the fingerprint identification chip exposed, an upper surface of a film layer of the fingerprint sensing region is provided with a protection layer with a predetermined thickness. The protection layer is exposed in the fingerprint sensing region outside the package structure and causes the fingerprint identification chip to have a predefined fingerprint identification distance. The fingerprint identification module and the package structure with a protection layer arranged on the upper surface of the fingerprint identification chip provide sufficient protections for fabrication processes such as downstream module assembly, while ensuring that the fingerprint identification chip has a predefined fingerprint identification distance.