Optical Sensor Package With Conductive Pillars for Miniaturization
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Solution Overview
Problem
The miniaturization of optical devices is hindered by the large area and thickness of substrates used in wire bonding techniques, which require additional space and height for wire bonding loops, limiting the compactness and efficiency of these devices.
Innovation Solution
The use of a circuit layer with an interconnection layer and dielectric layer, along with conductive pillars and an encapsulant, allows for the electrical connection of light detectors and emitters while exposing their active areas, reducing the device's thickness and area, and enabling a fan-out structure for miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding technique is used to electrically connect electronic components to substrate, then electrical connection is achieved, but substrate area and thickness increase due to wire bonding loops
Solution Approach 1:
The patent extracts the wire bonding process and replaces it with direct bonding technology. Electronic components are directly bonded to the substrate through conductive pillars and interconnection layers, eliminating the need for wire bonding loops and their associated space requirements.
Solution Approach 2:
The patent transitions from planar wire bonding connections to vertical three-dimensional interconnections using conductive pillars. Electrical connections are established through the thickness of the substrate via vertically extending conductive structures, reducing the horizontal space required for connections.
2Reliability
If wire bonding technique is used to electrically connect electronic components to substrate, then electrical connection is achieved, but device height increases due to wire bonding loops
Solution Approach 1:
The patent removes the wire bonding loops that contribute to device height. Instead, electronic components are directly bonded to the substrate surface, eliminating the vertical space required for wire bonding arcs and loops.
Solution Approach 2:
The patent shifts electrical connections from horizontal wire bonding paths to vertical conductive pillar structures. The interconnection layers and conductive pillars provide electrical pathways through the substrate thickness, reducing the overall device height profile.
3Reliability
If substrate with large area and thickness is used for wire bonding, then electrical connection is achieved, but device miniaturization is hindered
Solution Approach 1:
The patent replaces the mechanical wire bonding process with a direct bonding mechanism using conductive pillars and interconnection layers. This substitution enables miniaturization by eliminating the space-consuming wire bonding infrastructure while maintaining reliable electrical connections.
Solution Approach 2:
The patent employs three-dimensional vertical interconnection structures (conductive pillars extending through the substrate) to replace planar wire bonding. This dimensional change allows for compact device design by utilizing the vertical dimension for electrical connections rather than requiring extensive horizontal space.
Data Source
AI summary
An optical device includes a first circuit layer, a light detector, a first conductive pillar and an encapsulant. The first circuit layer has an interconnection layer and a dielectric layer. The light detector is disposed on the first circuit layer. The light detector has a light detecting area facing away from the first circuit layer and a backside surface facing the first circuit layer. The first conductive pillar is disposed on the first circuit layer and spaced apart from the light detector. The first conductive pillar is electrically connected to the interconnection layer of the first circuit layer. The encapsulant is disposed on the first circuit layer and covers the light detector and the first conductive pillar. The light detector is electrically connected to the interconnection layer of the first circuit layer through the first conductive pillar. The backside surface of the light detector is exposed from the encapsulant.