Image Sensor Isolation Wiring to Prevent Color Filter Striation
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Solution Overview
Problem
Current image sensor manufacturing processes face challenges in reducing defects and simplifying the production process, particularly in connecting the deep device isolation portion to the conductive pad without causing unintended striation defects during the formation of color filters.
Innovation Solution
The image sensor design incorporates a connection wiring structure and connection contact plugs that electrically connect the deep device isolation portion to the conductive pad through an interlayer insulating layer, allowing for voltage application to the deep device isolation portion without a contact structure on the second surface of the substrate, thus preventing process defects and providing flexibility in plug formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact structure is added on the second surface of the substrate to connect the deep device isolation portion to the conductive pad, then electrical connection is achieved, but the manufacturing process becomes more complex and defects may occur during color filter formation
Solution Approach 1:
Instead of adding a contact structure from the second surface to connect the deep device isolation portion, the patent inverts the approach by forming the connection from the first surface side. The connection contact plug is formed through the interlayer insulating layer to connect the connection wiring structure to the device isolation portion in the optical black region, eliminating the need for a contact structure on the second surface while achieving the same electrical connection function
Solution Approach 2:
The patent performs the connection earlier in the manufacturing process by forming the connection contact plug and connection wiring structure before forming the color filters. This preliminary action allows voltage to be applied to the deep device isolation portion during color filter formation, preventing unintended striation defects while simplifying the overall manufacturing process
2Manufacturing precision
If the deep device isolation portion is connected to the conductive pad, then voltage can be applied to prevent striation defects, but the manufacturing process becomes more complex
Solution Approach 1:
The connection wiring structure formed in the optical black region serves multiple functions: it provides electrical connection to the device isolation portion, enables voltage application during color filter formation to prevent striation defects, and does so using existing manufacturing steps without adding separate dedicated structures. This multi-functionality achieves defect reduction while avoiding increased process complexity
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
This design reduces unintended striation defects in color filters and simplifies the manufacturing process by enabling voltage application to the deep device isolation portion, minimizing defects and enhancing the image sensor's performance.
Implementation Method 1
a connection contact plug disposed in the interlayer insulating layer and connecting the connection wiring structure to the device isolation portion in the optical black region
Implementation Method 2
Each of the pixels may include a photodiode (PD). The photodiode may convert incident light into an electrical signal
Data Source
AI summary
An image sensor includes a first chip including a pixel region, a pad region, and an optical black region interposed between the pixel region and the pad region, and a second chip being in contact with a first surface of the first chip and including circuits for driving the first chip. The first chip includes a first substrate, a device isolation portion disposed in the first substrate and defining unit pixels, an interlayer insulating layer interposed between the first substrate and the second chip, a connection wiring structure disposed in the interlayer insulating layer, and a connection contact plug disposed in the interlayer insulating layer and connecting the connection wiring structure to the device isolation portion in the optical black region. The image sensor further includes a conductive pad disposed in the first chip or the second chip.