Image Sensor Light Shading Layer and Through Via
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Solution Overview
Problem
Image sensors experience malfunctions and noise due to external light transmission through the substrate from the rear side to the photoelectric converting portion, and existing technologies lack mechanical reliability in wire pads and external connection terminals.
Innovation Solution
An image sensor design featuring a light shading layer on the rear surface of the substrate, which is opaque to external light, and a stacked structure with insulating layers and wire pads, external connection terminals that are also opaque to external light, preventing light transmission and enhancing mechanical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the substrate is made transparent to allow light transmission to the photoelectric converting portion, then photoelectric conversion efficiency is improved, but external light from the rear side causes malfunctions and noise
Solution Approach 1:
The substrate surface is segmented into different functional regions: a first region with the photoelectric converting portion that requires light transmission, and a second region with the light shading layer that blocks external light. This segmentation allows each region to perform its specific function without interfering with the other, solving the contradiction between light transmission efficiency and external light interference.
Solution Approach 2:
Different regions of the substrate are given different optical properties: the first region maintains transparency for photoelectric conversion, while the second region is made opaque through the light shading layer to block external light. This local differentiation of properties allows the substrate to simultaneously achieve both light transmission for sensing and protection from external light interference.
2Ease of operation
If wire pads and external connection terminals are made thin and flexible for ease of connection, then ease of operation is improved, but mechanical reliability deteriorates
Solution Approach 1:
The connection structure uses a composite design combining wire pads extending from the substrate with external connection terminals that can be separately positioned and connected. This composite structure provides both the flexibility needed for easy connection and the structural integrity for mechanical reliability, as the wire pads can be routed appropriately while the external terminals provide stable connection points.
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
Substantially reduces or prevents external light-induced malfunctions and noise in the image sensor while increasing the mechanical reliability of wire pads and external connection terminals.
Implementation Method 1
a light shading layer formed on a portion of the rear surface of the substrate, wherein the light shading layer is substantially opaque with respect to an external light
Data Source
AI summary
One embodiment exemplarily described herein can be characterized as an image sensor including a substrate having a front surface and a rear surface; a photoelectric converting portion on the front surface of the substrate; a through via extending through the substrate, wherein the through via is electrically connected to the photoelectric converting portion; an external connection terminal on the rear surface of the substrate, wherein the external connection terminal is connected to the through via; and a light shading layer formed on a portion of the rear surface of the substrate, wherein the light shading layer is substantially opaque with respect to an external light. In some embodiments, the portion of the rear surface of the substrate on which the light shading layer is formed is not overlapped by the through via or the external connection terminal.