Through-Oxide Via Interconnect for Image Sensor Packaging
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Solution Overview
Problem
Conventional imaging systems face limitations in time, space, efficiency, and cost when forming via connections between the image sensor die and digital signal processing die due to the complexity of through-silicon via formation.
Innovation Solution
The implementation of through-oxide vias that connect the bond pad on the image sensor die to the digital signal processing die, allowing for a single structure and process to form both bond pad and inter-die connections, reducing the need for multiple masking layers and improving manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional through-silicon via connections are used to connect the image sensor die to the digital signal processing die, then reliable electrical connections are achieved, but the manufacturing time, space, efficiency, and cost are significantly increased
Solution Approach 1:
The patent changes the material parameter of the via structure from silicon-based (conventional) to oxide-based (new). By forming vias through oxide layers instead of silicon, the manufacturing process achieves both reliable electrical connections and improved productivity, as oxide etching and via formation can be integrated into existing CMOS fabrication processes without requiring additional complex steps
Solution Approach 2:
The patent merges the bond pad formation and inter-die connection formation into a single integrated process. The through-oxide via structure allows the bond pad to serve dual functions: as an electrical connection point on the first die and as an inter-die connection element, eliminating the need for separate via formation steps and reducing manufacturing complexity
2Reliability
If multiple via connections are formed to connect bond pads to digital signal processing die, then complete electrical interconnection is achieved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The through-oxide via structure serves multiple functions simultaneously: it provides electrical connection within the first die, serves as the inter-die connection element, and acts as the bond pad structure. This multi-functionality reduces the number of separate components and simplifies the overall device architecture while maintaining complete electrical interconnection
3Reliability
If conventional via formation processes are used, then connections are established, but the bond pad area increases and topography becomes more complex
Solution Approach 1:
The patent segments the via formation process into selective etching steps that create through-oxide vias with precise dimensional control. By etching through oxide layers rather than silicon, the via dimensions can be better controlled and optimized, reducing the required bond pad area while maintaining reliable electrical connections
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 approach reduces the bond pad area, minimizes topography, and decreases manufacturing costs while enhancing process integration and yield, allowing for more efficient image sensor package production.
Implementation Method 1
depositing conductive material in the hole to form a via in the hole
Implementation Method 2
performing selective etching to form a hole that extends into the first and second dies
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
An imaging system may include an image sensor package with through-oxide via connections between the image sensor die and the digital signal processing die in the image sensor package. The image sensor die and the digital signal processing die may be attached to each other. The through-oxide via may connect a bond pad on the image sensor die with metal routing paths in the image sensor and digital signal processing dies. The through-oxide via may simultaneously couple the image sensor die to the digital signal processing die. The through-oxide via may be formed through a shallow trench isolation structure in the image sensor die. The through-oxide via may be formed through selective etching of the image sensor and digital signal processing dies.