Stacked Image Sensor Isolation Wiring to Prevent Color Filter Defects
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Solution Overview
Problem
Current image sensor manufacturing processes face challenges in reducing defects and simplifying the process, particularly in connecting the conductive pad to the deep device isolation portion without causing unintended striation defects during color filter formation.
Innovation Solution
The image sensor design includes a connection wiring structure and connection contact plugs that electrically connect the conductive pad to the deep device isolation portion through the optical black region, allowing for voltage application without surface contact, thus preventing process defects and enabling flexible plug formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the conductive pad is connected to the device isolation portion through surface contact in the optical black region, then the manufacturing process is simplified, but unintended striation defects occur during color filter formation
Solution Approach 1:
The connection contact plug extends vertically into the optical black region to connect the connection wiring structure to the device isolation portion, moving the connection from a surface-level contact to a subsurface vertical connection. This dimensional change allows the color filter to be formed without contacting the conductive pad, preventing striation defects while maintaining manufacturing simplicity.
2Manufacturing precision
If the connection contact plug is formed to connect the connection wiring structure to the device isolation portion in the optical black region, then striation defects are prevented, but the device complexity increases
Solution Approach 1:
The connection contact plug acts as an intermediary element that vertically connects the connection wiring structure to the device isolation portion through the optical black region. This intermediary structure enables the color filter to be formed without direct contact with conductive elements, preventing striation defects while integrating seamlessly into the existing device architecture.
3Object-affected harmful factors
If voltage is applied to the device isolation portion through surface contact, then noise reduction is effective, but process defects occur during manufacturing
Solution Approach 1:
The voltage application path is moved from surface contact to a vertical subsurface connection through the connection contact plug. This allows the device isolation portion to be electrically connected for noise reduction purposes without exposing conductive elements at the surface where the color filter is formed, thereby preventing manufacturing defects.
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 or minimizes defects such as dark current and white spots, simplifies the manufacturing process, and allows for effective noise reduction by applying voltage to the deep device isolation portion without surface contact, enhancing image sensor performance.
Implementation Method 1
connection contact plugs 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.