CMOS Image Sensor Package Interlocking Glass Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
CMOS image sensor packages face reliability issues during high-temperature testing due to detachment of the adhesive layer from the CIS chip and glass, which compromises the adhesion strength.
Innovation Solution
Incorporating interlocking recesses and protrusions on the CIS chip and glass, with the adhesive layer featuring interlocking protrusions that fit into these recesses, increasing the contact area and reinforcing the adhesion strength, and a molding member to support the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional adhesive layer is used to attach the glass to the CIS chip, then the structure is simple and easy to manufacture, but the adhesion strength is insufficient and the adhesive layer detaches during high-temperature testing
Solution Approach 1:
The invention transitions from a planar adhesive interface to a three-dimensional interlocking structure by forming protrusions and recesses. The adhesive layer includes protrusions that extend into recesses formed on the glass and CIS chip surfaces, creating vertical engagement beyond the simple horizontal bonding plane. This dimensional transformation significantly enhances adhesion strength while maintaining manufacturing feasibility through standard molding processes.
Solution Approach 2:
The adhesive layer is segmented into multiple functional regions: protrusions that engage with recesses on the glass and CIS chip, and recesses that accommodate protrusions from opposing components. This segmentation creates distributed mechanical interlocking points throughout the adhesive layer, preventing catastrophic failure and ensuring reliable attachment during high-temperature testing.
2Strength
If the contact area between the adhesive layer and the CIS chip/glass is increased, then the adhesion strength is reinforced, but the manufacturing precision requirements increase due to the need for precise interlocking features
Solution Approach 1:
The invention optimizes geometric parameters of the interlocking features to balance adhesion strength and manufacturing precision. The width of protrusions and recesses is controlled within specific ranges (e.g., 20-50 μm for protrusion width, 5-20 μm for recess depth) to ensure adequate mechanical interlocking while remaining compatible with standard semiconductor manufacturing tolerances. These parameter specifications enable mass production without requiring ultra-precision machining.
Solution Approach 2:
The adhesive layer functions as a composite structure combining the adhesive material itself with integrated mechanical interlocking features. This composite approach merges chemical adhesion (from the adhesive material) with mechanical interlocking (from protrusions and recesses), achieving superior bond strength that tolerates moderate variations in manufacturing precision while still providing reliable high-temperature performance.
Data Source
AI summary
A CMOS image sensor (CIS) package includes a package substrate, a CIS chip arranged on an upper surface of the package substrate and electrically connected with the package substrate, a glass arranged over the CIS chip, and an adhesive layer interposed between an edge portion of an upper surface of the CIS chip and an edge portion of a lower surface of the glass to attach the glass to the CIS chip. An interlocking recess is provided to at least one of the CIS chip and the glass, and the adhesive layer comprises an interlocking protrusion inserted into the interlocking recess.