Optical Sensor Module 3D Stacked ASIC Die Integration
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Solution Overview
Problem
Current optical sensor packaging schemes are inefficient in terms of size, cost, and performance due to separate packaging of optical sensor and ASIC dies, which occupy significant space and hinder miniaturization efforts in the electronics industry.
Innovation Solution
A three-dimensional wafer-level integration of optical sensor modules is achieved by stacking an optical sensor die with an ASIC die that has a hole aligned with the optical sensing area, providing a direct die-to-die connection for robust electrical and mechanical interconnection without bonding wires, and using adhesive for both mechanical and electrical interconnection while blocking light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If separate packaging schemes are used for optical sensor die and ASIC die, then electrical connection and signal processing can be achieved, but the overall package size becomes large and miniaturization is hindered
Solution Approach 1:
The patent merges the optical sensor die and ASIC die into a single integrated package structure. The ASIC die is positioned directly over the optical sensor die with through-holes aligned to the sensing area, eliminating the need for separate packaging. This consolidation reduces the overall volume while maintaining electrical connection and signal processing functions through direct die-to-die coupling.
Solution Approach 2:
The patent transitions from a planar side-by-side arrangement to a three-dimensional stacked configuration. The ASIC die is placed vertically above the optical sensor die, with through-holes extending through the ASIC die to align with the optical sensing area. This vertical stacking in the Z-dimension reduces the footprint and overall package size while maintaining functional separation.
2Length of moving object
If traditional packaging materials and structures are used, then protection of sensitive components is achieved, but the profile height increases and board mounting space is consumed
Solution Approach 1:
The patent extracts and eliminates traditional packaging materials such as molds, lids, and encapsulants from the optical sensor module. The ASIC die itself serves as the protective housing, with its top surface providing protection for the optical sensor die. This removal of extraneous packaging layers significantly reduces the profile height while maintaining component protection through the structural integrity of the stacked die assembly.
3Manufacturing precision
If through-holes are formed in ASIC die for optical alignment, then direct optical path and compact integration are achieved, but manufacturing complexity increases
Solution Approach 1:
The through-holes are formed in the ASIC die during the semiconductor fabrication process, before the die is packaged or mounted. This preliminary formation of alignment holes ensures precise optical alignment is built into the die structure itself, eliminating the need for post-packaging alignment adjustments. The holes are created with precise dimensions and positions using standard semiconductor manufacturing techniques such as photolithography and etching.
Data Source
AI summary
An integrated optical sensor module includes an optical sensor die having an optical sensing area on its first surface, and an application-specific integrated circuit (ASIC) die arranged over the first surface of the optical sensor die. A hole in the ASIC die is at least partially aligned with the optical sensing area such that at least some of the light passing through the hole may contact the optical sensing area. The hole through the ASIC die can be configured to receive an optical fiber, lens structure, or other optical element therein.