Fingerprint Sensor Package Module Masking Layer Process
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Solution Overview
Problem
During the encapsulation process of fingerprint sensor package modules, the encapsulating material often overflows and stains the sensing region of the fingerprint sensor chip, reducing its sensitivity and affecting production yield, and there is a need to miniaturize the module size due to limited installation space in electronic devices.
Innovation Solution
A process involving a substrate with a mounting and surrounding region, where a fingerprint sensor chip is disposed with a masking layer on the sensing region, followed by electrical connection, molding of an encapsulation structure that confines the masking layer, and subsequent removal to expose the sensing region, allowing for reduced spacing between electric contacts and the sensing region, thereby preventing material overflow and enabling miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encapsulation is performed without a masking layer, then the encapsulation structure can fully cover the surrounding region, but the encapsulating material overflows and stains the sensing region, reducing sensitivity and production yield
Solution Approach 1:
A masking layer is formed on the sensing region before the encapsulation process. This preliminary protective action prevents encapsulating material from contacting and staining the sensing region, thereby maintaining sensor sensitivity and improving production yield without affecting the encapsulation coverage of the surrounding region
Solution Approach 2:
The masking layer acts as an intermediary barrier between the encapsulating material and the sensing region. It allows the encapsulation process to proceed with full coverage while preventing harmful contact with the sensitive sensing area, resolving the contradiction between comprehensive encapsulation and sensitivity protection
2Volume of moving object
If the spacing between electric contacts and sensing region is reduced to enable miniaturization, then the module size decreases for limited installation space, but the encapsulation process becomes more difficult without causing material overflow onto the sensing region
Solution Approach 1:
The masking layer is applied to the sensing region before encapsulation, creating a protective barrier that enables safe miniaturization. This preliminary protection allows electric contacts to be positioned closer to the sensing region without risk of encapsulating material overflow causing defects, thus enabling module miniaturization while maintaining ease of manufacture
Solution Approach 2:
The masking layer serves as an intermediary that decouples the spacing reduction from encapsulation difficulty. It allows the electric contacts to be positioned close to the sensing region for miniaturization while preventing encapsulation material from reaching the sensing area, thereby resolving the contradiction between compact size and manufacturing ease
Data Source
AI summary
A method for making a fingerprint sensor package module includes the steps of: providing a substrate, disposing a fingerprint sensor chip over a mounting region of the substrate, forming a masking layer on a sensing region of the fingerprint sensor chip, electrically connecting the substrate to the fingerprint sensor chip, molding an encapsulation structure, and removing the masking layer to expose the sensing region of the fingerprint sensor chip.