Conductive Pad Exposure in Optical Sensor Semiconductor Fabrication
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Solution Overview
Problem
Existing semiconductor manufacturing methods for fingerprint identification devices face challenges in yield and reliability, particularly in protecting conductive pads during processing to maintain electrical connections.
Innovation Solution
A method involving the formation of semiconductor devices with transparent collimating pillars and a light-shielding structure, where a cutting process is followed by an etching process to expose conductive pads, ensuring protection and precise material removal to enhance yield and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cutting process is performed to remove material above the conductive pad, then material removal efficiency is improved, but the conductive pad may be damaged
Solution Approach 1:
A protective layer is formed over the conductive pad before the cutting process. This preliminary protective action allows the cutting process to proceed efficiently while the protective layer prevents damage to the conductive pad. After cutting, the protective layer remains to shield the pad during subsequent etching processes.
Solution Approach 2:
The protective layer acts as an intermediary between the cutting process and the conductive pad. It absorbs the mechanical stress and potential damage from the cutting process, allowing efficient material removal while protecting the underlying conductive pad from damage.
2Manufacturing precision
If an etching process is performed to remove remaining material, then complete exposure of the conductive pad is achieved, but the conductive pad may be damaged by the etching process
Solution Approach 1:
The protective layer is formed in advance before the etching process. This preliminary protective measure enables precise etching of the remaining material to expose the conductive pad while the protective layer prevents the etchant from damaging the pad itself.
Solution Approach 2:
The protective layer serves as an intermediary that allows the etching process to remove the light-shielding structure material precisely while blocking the etchant from contacting and damaging the conductive pad. The layer is selectively removed after etching to complete the exposure.
3Reliability
If the protective layer completely covers the conductive pad, then protection during cutting is improved, but complete exposure after processing becomes difficult
Solution Approach 1:
The protective layer is segmented into different functional zones: a first portion that remains over the conductive pad during cutting and etching to provide protection, and a second portion that is removed to allow complete exposure of the pad. This segmentation allows simultaneous protection and controlled exposure.
Solution Approach 2:
The protective layer is preliminarily applied to cover the conductive pad, providing protection during processing. Subsequently, selective removal of portions of the protective layer is performed to achieve complete exposure when needed, maintaining both protection during processing and exposure capability.
Data Source
AI summary
A method for forming semiconductor devices includes providing a substrate with a conductive pad formed thereon; forming a transparent structure over the substrate, wherein the transparent structure includes a plurality of collimating pillars adjacent to the conductive pad; forming a light-shielding structure over the plurality of collimating pillars and the conductive pad; performing a cutting process to remove one or more materials directly above the conductive pad, while leaving remaining material to cover the conductive pad, wherein the material includes a portion of the light-shielding structure; and performing an etching process to remove the remaining material to expose the conductive pad.