Imaging Element Rewiring Layout for Narrow-Pitch Low-Profile Packaging
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Solution Overview
Problem
Conventional imaging devices face challenges in reducing size and height due to high processing costs and potential tilting of the first die within the cavity, especially with increased pixel count and functionality.
Innovation Solution
The imaging device incorporates a rewiring region outside the pixel area, a mold part formed around the imaging element, and a rewiring layer connecting external terminals and pads on the pixel formation surface, with insulating layers to reduce size and height, and through vias for electrical connection, allowing for narrower pad spacing and efficient mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a first die receiving cavity is formed on the substrate with conductive wiring inside, then electrical connection is achieved, but the processing cost increases and height reduction becomes difficult due to potential die tilting
Solution Approach 1:
The invention divides the substrate into multiple regions: a first region with through-holes for through-vias, a second region with recesses for receiving the first die, and a third region for receiving a second die. This segmentation allows different connection methods (through-vias vs. surface-mounted pads) to be used in different areas, reducing overall processing complexity and cost while maintaining reliable electrical connections.
Solution Approach 2:
The invention transitions from three-dimensional through-hole via connections to two-dimensional surface-mounted pad connections for the second die. By forming pads on the surface of the substrate in the third region rather than creating deep recesses or through-holes, the manufacturing process is simplified, reducing processing cost while maintaining electrical connection reliability.
2Volume of moving object
If the pitch between pins is narrowed to reduce package size, then downsizing is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The substrate is segmented into regions with different pin pitch configurations. The first region accommodates through-vias with one pitch, while the second and third regions accommodate surface-mounted pads with different pitches. This allows the package to be downsized in certain areas without requiring uniform high-precision manufacturing across the entire substrate, as different regions can be optimized independently.
Solution Approach 2:
Different regions of the substrate have different local qualities in terms of pad configuration and pitch. The second region has recesses with specific dimensions for receiving the first die, while the third region has pads for the second die. This local differentiation allows narrow pitch in critical areas while maintaining manufacturability in other areas, balancing downsizing with manufacturing precision requirements.
3Reliability
If a mold part is formed around the imaging element, then protection and structural support are provided, but device height increases
Solution Approach 1:
The mold part is designed to nest around the imaging element and circuit elements in a space-efficient manner. The recesses in the substrate are formed to specific depths that accommodate the first and second dies without requiring excessive mold part height. This nesting approach provides the necessary protection and structural support while minimizing the increase in device height.
Solution Approach 2:
The dimensions of the recesses and mold part are optimized to achieve the desired balance between protection and height. By carefully controlling the depth and width parameters of the recesses in the second and third regions, the mold part can provide adequate structural support while keeping the overall device height minimized for compact applications.
Data Source
AI summary
A rewiring region 22 is provided in a region other than a pixel region 21 on a front face (pixel formation surface) FA of an imaging element 20. A mold part 30 is formed around the imaging element 20 other than on the front face FA. Rewiring layers 41b, 42b, and 43b that connect an external terminal and a pad 23 provided in the rewiring region 22 are formed via insulating layers 41a, 42a, and 43a on a side of the pixel formation surface of the imaging element 20 and the mold part 30. Therefore, connection to a substrate can be made possible even if the spacing between the pads is narrowed, a mounting surface of an imaging device 10 is also on the side of the pixel formation surface, and reduction in size and height can be achieved.