Image Sensor Package Stepped Substrate Holder Attachment
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Solution Overview
Problem
Image sensor packages face challenges in reducing package size and improving reliability, as existing designs are limited by the height of guide pins used to attach holders, which restricts thickness reduction and adhesive area expansion.
Innovation Solution
The design incorporates a stepped portion along the edges of the package substrate with a holder attachment area, where the holder is adhered without a guide pin, increasing the adhesive area and enhancing sealing effects, while reducing the package thickness and preventing contamination of pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guide pins are used to attach the holder to the package substrate, then the holder can be securely positioned, but the package thickness cannot be reduced and the adhesive area is limited
Solution Approach 1:
The patent removes the guide pin component from the holder attachment structure and replaces it with a stepped portion on the package substrate. This extraction eliminates the thickness constraint imposed by guide pins while maintaining secure holder attachment through increased adhesive surface area on the stepped structure.
Solution Approach 2:
The patent transitions from a single-plane attachment method (guide pins) to a multi-level stepped structure. The stepped portion creates multiple surfaces (top surface and side surfaces) for adhesive attachment, effectively utilizing three-dimensional space to increase bonding area without increasing overall package thickness.
2Reliability
If guide pins are used to attach the holder, then positioning is secure, but the adhesive area is limited
Solution Approach 1:
The stepped portion creates multiple attachment surfaces including the top surface and vertical side surfaces, transforming a two-dimensional adhesive interface into a three-dimensional bonding structure. This increases the total adhesive area available for securing the holder without requiring additional horizontal space.
Solution Approach 2:
The stepped structure concentrates adhesive attachment areas at specific locations where the holder contacts the substrate. By creating localized stepped portions with enhanced surface area, the design optimizes adhesive bonding efficiency at critical attachment points rather than uniformly distributing the structure.
3Device complexity
If the holder attachment area is at the same level as the pad area, then the structure is simple, but the holder may shift or peel and contamination can occur
Solution Approach 1:
The package substrate is segmented into distinct functional areas: a pad area at one level and a holder attachment area with stepped portions at a different level. This segmentation separates the electrical connection function from the mechanical attachment function, allowing each to be optimized independently while preventing interference between them.
Solution Approach 2:
The stepped portions create an asymmetric profile in the holder attachment area, with vertical sides and varying heights. This asymmetric structure provides mechanical interlocking and prevents holder shifting or peeling, while the lower level of the stepped portions acts as a barrier to prevent contamination from reaching the pad area.
Data Source
AI summary
An image sensor package may include: a package substrate including a chip attachment area on an upper surface thereof, a pad area having a plurality of pads around the chip attachment area, and a holder attachment area at an outside of the pad area, wherein an upper surface of the holder attachment area is at a lower level than an upper surface of the pad area; an image sensor chip mounted on the chip attachment area of the package substrate; a transparent member above the package substrate and configured to cover the image sensor chip; and a holder on the holder attachment area of the package substrate and configured to fix the transparent member.