Sensor Package Convex Structure for Bubble-Free Chip Bonding
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Solution Overview
Problem
Air bubbles generated during the adhesion process between a sensing chip and a substrate in image sensor packaging can lead to insufficient adhesion strength and impaired heat conduction, affecting the reliability and performance of the package structure.
Innovation Solution
A sensor package structure is designed with a convex structure on the substrate's solder mask layer, where the engaging layer covers the convex structure, allowing air to be squeezed out during chip adhesion, reducing residual air bubbles and enhancing adhesion strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a liquid adhesive material or die attach film is used to bond the sensing chip and substrate, then adhesion is achieved, but air bubbles are generated on the adhesive surface and remain in the cured adhesive layer
Solution Approach 1:
A convex structure is formed on the substrate surface at the bonding location before the adhesive bonding process. This preliminary structural modification creates a pathway for air bubbles to escape during adhesion, preventing them from being trapped in the adhesive layer and thereby maintaining both adhesion strength and package reliability
Solution Approach 2:
The convex structure acts as an intermediary element between the substrate and sensing chip. It modifies the bonding interface by providing a controlled air escape route, allowing the adhesive to bond the components effectively while eliminating the harmful effect of trapped air bubbles
2Ease of manufacture
If air bubbles remain in the adhesive layer, then the adhesion process is simplified, but adhesion strength becomes insufficient and heat conduction is impeded
Solution Approach 1:
The convex structure is pre-formed on the substrate before adhesive application. This preliminary action creates an automatic air bubble expulsion mechanism during bonding without complicating the adhesion process, maintaining ease of manufacture while ensuring sufficient adhesion strength
3Ease of manufacture
If air bubbles remain in the adhesive layer, then the bonding process is straightforward, but heat conduction is impeded and heat dissipation becomes difficult
Solution Approach 1:
The convex structure is formed in advance on the substrate, creating a pathway that allows air bubbles to escape during bonding. This maintains bonding process simplicity while ensuring continuous thermal contact between the sensing chip and substrate, thereby improving heat dissipation efficiency
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 convex structure design effectively reduces air bubbles within the adhesive layer, improving the adhesion strength and heat dissipation capabilities of the package structure, thereby enhancing its reliability and performance.
Implementation Method 1
the air is squeezed from the inside to diffuse outward, and the residual air bubbles inside the engaging layer can be reduced
Data Source
AI summary
A sensor package structure and a manufacturing method thereof are provided. The sensor package structure includes a substrate, a first solder mask layer, a convex structure, a sensing chip, and an engaging layer. The first solder mask layer is disposed on the substrate. The convex structure is disposed on the first solder mask layer. The convex structure has a first stepped surface, and the first stepped surface is higher than an upper surface of the first solder mask layer. The sensing chip is disposed above the substrate. The engaging layer is adhered between the substrate and the sensing chip and covers the convex structure, such that the convex structure and the sensing chip are not in contact with each other.