Image Sensor Interposed Layer Shielding and Diffusion Barrier
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Solution Overview
Problem
The demand for high-density image sensors with reduced pixel size is increasing, but existing technologies face challenges in effectively managing electrical coupling and charge diffusion between pixel array chips and logic chips, which affects the performance and reliability of image sensors.
Innovation Solution
The implementation of an image sensor design that includes a pixel array chip, a logic chip, and an interposed layer with a connecting part, a shielding part, and a metal-diffusion barrier layer. The interposed layer electrically connects the pixel array chip to the logic chip, while the shielding part suppresses electrical coupling, and the metal-diffusion barrier layer limits charge diffusion, using materials like copper and tungsten for the connecting and shielding parts and silicon-based materials for the diffusion barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pixel size is reduced to increase density, then the productivity and integration density are improved, but the electrical coupling and charge diffusion between chips worsen
Solution Approach 1:
An interposed layer is introduced between the pixel array chip and logic chip to provide electrical connection while incorporating shielding parts and metal-diffusion barrier layers to block harmful electrical coupling and charge diffusion, enabling high-density integration without sacrificing signal integrity
Solution Approach 2:
The interposed layer features spatially differentiated structures: connecting parts for electrical connection, shielding parts for electromagnetic shielding, and metal-diffusion barrier layers for preventing charge diffusion, with each part optimized for its specific function to address local electrical interference issues
2Productivity
If the pixel size is reduced to increase density, then the integration density is improved, but the charge diffusion to chips worsens
Solution Approach 1:
The metal-diffusion barrier layer acts as an intermediary barrier between the interposed layer and the chips, selectively blocking metal atom diffusion while allowing electrical connection through designated pathways, thus preventing contamination and maintaining reliability in high-density configurations
Solution Approach 2:
The harmful metal diffusion process is extracted and blocked by the metal-diffusion barrier layer, separating the beneficial electrical connection function from the harmful charge diffusion, allowing high-density integration without compromising chip reliability
3Reliability
If connecting parts are added to electrically connect chips, then the electrical connection is improved, but the electrical coupling between chips worsens
Solution Approach 1:
The interposed layer is segmented into distinct functional parts: connecting parts for electrical connection, shielding parts for electromagnetic shielding, and barrier layers for diffusion prevention, allowing electrical connection to be achieved while isolating harmful coupling effects through spatial separation
Solution Approach 2:
The shielding part serves as an intermediary element that is electrically grounded to intercept and divert electromagnetic interference, protecting the electrical connection between chips from harmful coupling while maintaining signal integrity
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 enhances the electrical isolation between the pixel array and logic chips, improving the performance and reliability of image sensors by reducing electrical coupling and charge diffusion, thereby supporting higher density and smaller pixel sizes.
Implementation Method 1
The shielding part is disposed spatially apart from the connecting part and electrically grounded to suppress an electrical coupling between the pixel array chip and the logic chip
Implementation Method 2
The metal-diffusion barrier layer is disposed on top and bottom surfaces of the interposed layer to limit diffusion of electrical charges to the pixel array chip and the logic chip
Data Source
AI summary
An image sensor includes a pixel array chip, a logic chip, and an interposed layer. The interposed layer is disposed on the pixel array chip. The logic chip is disposed on the interposed layer. The interposed layer includes a connecting part, a shielding part, and a metal-diffusion barrier layer. The connecting part electrically connects a first interconnection wire of the pixel array chip and a second interconnection wire of the logic chip. The connecting part includes a first metallic element. The shielding part is disposed spatially apart from the connecting part and electrically grounded to suppress an electrical coupling between the pixel array chip and the logic chip. The shielding part includes a second metallic element. The metal-diffusion barrier layer is disposed on top and bottom surfaces of the interposed layer to limit diffusion of electrical charges to the pixel array chip and the logic chip.