Image Sensor Pickup Layout for 3D IC Package Area Reduction
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Solution Overview
Problem
The packaging area for MOS sensors and their related ASICs in 3D integrated circuits is large, necessitating methods to reduce the package area for improved density and efficiency in image sensor applications.
Innovation Solution
The design involves a layout where pickups in the array area and non-array areas of the image sensor device are similarly sized, allowing for optimized lithography processes and reduced critical dimensions, with the non-array area being densely packed to minimize size without compromising the array area, thereby enhancing fill factor and light sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If MOS sensors and ASICs are bonded to carrier wafer in parallel in 3D IC packaging, then high density is achieved, but package area increases
Solution Approach 1:
The patent combines the sensor array area and non-array area pickups into a single integrated substrate structure, merging previously separate packaging components into one unified device. This integration eliminates the need for separate carrier wafer bonding and reduces overall package area while maintaining high component density.
Solution Approach 2:
The non-array area pickups are positioned within the periphery area that surrounds the array area, creating a nested layout where one functional area is contained within the boundary of the overall sensor structure. This nested arrangement optimizes space utilization and minimizes the total package footprint.
2Area of stationary object
If non-array area is densely packed to minimize size, then package area is reduced, but lithography critical dimensions are challenged
Solution Approach 1:
The patent applies different design characteristics to different regions: the array area pickups maintain larger, more robust dimensions suitable for high-precision lithography, while the non-array area pickups in the periphery utilize optimized smaller dimensions. This local differentiation allows dense packing in the periphery without compromising the manufacturing precision of critical array elements.
Solution Approach 2:
The invention changes the dimensional parameters of pickups based on their location - array area pickups have one set of dimensions optimized for light sensitivity, while non-array area pickups have different dimensions optimized for space efficiency. This parameter variation enables the lithography process to accommodate both high-density packing and manufacturing precision requirements.
3Illumination intensity
If array area pickups are larger to improve light sensitivity, then fill factor increases, but non-array area space is reduced
Solution Approach 1:
The patent implements location-specific pickup designs where array area pickups are optimized with larger dimensions and higher fill factors for maximum light sensitivity, while non-array area pickups in the periphery are designed with compact dimensions to preserve space. This local quality differentiation resolves the contradiction between light sensitivity requirements and space constraints.
Solution Approach 2:
The invention utilizes the peripheral dimension around the array area to position non-array pickups, effectively using the two-dimensional space surrounding the primary array. This dimensional approach allows both large array pickups for light sensitivity and compact non-array pickups to coexist without direct spatial conflict.
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 package area, increases the fill factor, and improves the performance-per-area of image sensors by allowing for more efficient use of space and optimized lithography, leading to enhanced image quality and sensitivity.
Implementation Method 1
a photodiode formed in a silicon substrate. As the photodiode is exposed to light, an electrical charge is induced in the photodiode. Each sensor, or pixel, may generate electrons proportional to the amount of light that falls on the pixel
Data Source
AI summary
Embodiments of the present disclosure include an image sensor device and methods of forming the same. An embodiment is an image sensor device including a first plurality of pickup regions in a photosensor array area of a substrate, each of first plurality of pickup regions having a first width and a first length, a second plurality of pickup regions in a periphery area of the substrate, the periphery area along at least one side of the photosensor array area, each of second plurality of pickup regions having a second width and a second length.