Semiconductor Package Dam Recess for Adhesive Containment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor packaging methods for photosensitive chips, such as CMOS image sensors, face issues with adhesive leakage and contamination due to the flat top of the dam, leading to manufacturing yield loss and poor packaging reliability.
Innovation Solution
A semiconductor package design featuring a substrate with a dam and a recess or wall to prevent adhesive leakage, where the adhesive is retained within the recess or wall, ensuring secure attachment of the cover and minimizing contamination of the photosensitive area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat top dam structure is used for attaching the transparent cover, then the attachment process is simple, but adhesive leakage occurs and contaminates the photosensitive chip
Solution Approach 1:
The dam top surface is modified from flat to curved/concave shape, creating a recessed area that holds the adhesive in place during the attachment process, preventing it from flowing onto the photosensitive chip while maintaining secure bonding between the cover and substrate
2Strength
If compression is applied between the transparent cover and dam top, then the adhesive bonds firmly, but adhesive leakage increases
Solution Approach 1:
The curved/concave top surface of the dam creates a natural containment area for the adhesive, allowing compression force to be applied for strong bonding while the curved geometry prevents the adhesive from spreading outward and leaking onto the photosensitive chip
3Reliability
If adhesive is applied to attach the cover to the dam, then secure attachment is achieved, but adhesive may flow onto the expose area causing contamination
Solution Approach 1:
The recessed curved surface of the dam top acts as a barrier that contains the adhesive within the attachment zone, preventing it from flowing outward onto the expose area and contaminating the photosensitive chip, while still allowing sufficient adhesive to be present for secure bonding
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
The proposed design significantly reduces adhesive leakage and contamination, enhancing packaging reliability and yield by effectively directing and retaining the adhesive, thus improving the bonding between the cover and the dam.
Implementation Method 1
After heating and applying pressure, the adhesive melts and solidifies to firmly attach the lid onto the top of the dam
Data Source
AI summary
A semiconductor package. The semiconductor package of the invention comprises: a substrate comprising at least one exposed area with photosensitive devices; a cover for isolating the exposed area from the external atmosphere, wherein one of either the substrate or the cover is a base, and the other is a top structure; and a dam formed on the base to form a cavity, wherein the top of the dam has a recess, the dam is attached the top structure by an adhesive, and the cavity corresponds to the exposed area.