Semiconductor Image Sensor Coplanar Cylindrical Electrodes
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Solution Overview
Problem
Conventional semiconductor image sensors face challenges in reducing size and thickness due to external electrical connections and are prone to optical noise from reflected light, such as flares and smears, caused by the structure of gold wires.
Innovation Solution
A semiconductor image sensor design featuring a semiconductor imaging element with a transparent resin layer and cylindrical electrodes formed on the electrode terminals, where the electrodes' upper surfaces are in the same plane as the resin layer, eliminating the need for rerouting wires and reducing the sensor's thickness and size. Additionally, antireflection films on the electrodes or transparent sheets can prevent light reflection and optical noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If electrical connection is made by extending connection means beyond the periphery of the semiconductor substrate, then through-hole conductors can be eliminated and package thickness reduced, but the plan dimension of the semiconductor image sensor increases
Solution Approach 1:
The patent moves the electrical connection interface from the peripheral extension direction to the same plane as the imaging element surface. Cylindrical electrodes are formed on the electrode terminals such that their upper surfaces exist in the same plane as the upper surface of the transparent resin layer, effectively utilizing the surface plane dimension rather than extending beyond the substrate periphery. This dimensional repositioning resolves the contradiction by maintaining thin package profile while avoiding increased plan dimension.
2Reliability
If gold wires are used to establish electrical connection, then reliable electrical connection is achieved, but reflected light from the wires enters the imaging area causing flares and smears
Solution Approach 1:
The patent extracts the harmful reflective property from the electrical connection structure by eliminating the upright portions of metal wires that cause light reflection. Instead of using traditional gold wires with vertical segments, the invention employs cylindrical electrodes formed on electrode terminals with upper surfaces coplanar with the transparent resin layer. This extraction of the harmful geometric feature (upright wire portions) maintains electrical connection reliability while eliminating the optical noise generation mechanism.
Solution Approach 2:
The patent applies different geometric qualities to different parts of the connection structure. The cylindrical electrodes have a specific local geometry where the upper surface is coplanar with the transparent resin layer, creating a locally optimized structure that prevents light reflection at the connection point. This local quality modification targeted at the electrode surface geometry resolves the optical noise issue without compromising overall electrical connection reliability.
3Area of stationary object
If the sensor is reduced in size and thickness, then high-density packaging is achieved, but optical noise suppression becomes more difficult
Solution Approach 1:
The patent implements preliminary action by designing the cylindrical electrode structure and coplanar surface configuration before light reflection issues can manifest. The upper surfaces of the cylindrical electrodes are formed to exist in the same plane as the upper surface of the transparent resin layer during the fabrication process, proactively preventing light reflection paths before they can cause flares or smears. This preliminary structural arrangement enables small sensor size while maintaining optical noise suppression capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design results in a significantly thinner and smaller semiconductor image sensor with reduced planar area, effectively minimizing optical noise and improving optical characteristics, while maintaining long-term reliability and suppressing flares and smears.
Implementation Method 1
a transparent resin layer formed on a circuit-formation surface of the semiconductor imaging element
Implementation Method 2
cylindrical electrodes formed on the electrode terminals, having an upper surface existing in the same plane as an upper surface of the transparent resin layer, and provided for connection with the external device
Implementation Method 3
antireflection films on the electrodes or transparent sheets can prevent light reflection and optical noise
Data Source
AI summary
A semiconductor image sensor includes: a semiconductor imaging element including an imaging area, a peripheral circuit area, and an electrode area; cylindrical electrodes provided on electrode terminals so as to be electrically connected with an external device; and a transparent resin layer provided on the upper surface of the semiconductor imaging element. The upper surface of each cylindrical electrode and the upper surface of the transparent resin layer are substantially of the same height.