Plated Bump Surface Segmentation for Reliable Device Bonding
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Solution Overview
Problem
Existing methods for bonding semiconductor devices, such as the flip chip method, face challenges in ensuring reliable electrical connections and sealing due to issues with filler particles getting caught in the bonding interface, particularly when using non-conductive films or pastes with inorganic filler particles.
Innovation Solution
A device-bonded body is created using plated bumps with a unique surface structure, featuring a first area and a second area, where the second area is higher than the first and its side surface intersects with the first area, and a sealing layer made of non-conductive film or paste with inorganic filler particles, which is applied before bonding to enhance workability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sealing resin including inorganic filler particles is applied before bonding (first-in method), then workability is improved, but filler particles may get caught in the bonding interface reducing reliability
Solution Approach 1:
The bump surface is segmented into different height areas (first area and second area higher than the first area). This segmentation creates distinct zones that control filler particle distribution, allowing the sealing resin to be applied before bonding without particles getting caught in the bonding interface, thus maintaining both workability and reliability
Solution Approach 2:
Different areas of the bump surface are given different local qualities through height variation. The first area (lower) and second area (higher) have different properties that control where filler particles settle, ensuring particles are localized in specific areas away from the bonding interface while maintaining good workability during application
2Ease of manufacture
If a flat bump surface is used, then manufacturing is simple, but filler particles accumulate at the bonding interface reducing adhesion strength
Solution Approach 1:
The bump surface is made asymmetric with respect to height, creating a first area and a second area that is higher than the first area. This asymmetric structure prevents filler particles from accumulating uniformly at the bonding interface, thereby maintaining adhesion strength while remaining manufacturable through standard plating processes
Solution Approach 2:
The solution moves from a two-dimensional flat surface to a three-dimensional surface with height variations. By introducing the height dimension (first area vs. second area higher than the first area), the design controls filler particle distribution in the vertical dimension, preventing particle accumulation at the bonding interface and maintaining adhesion strength
Data Source
AI summary
A device-bonded body includes: a first device where a plated bump is disposed; a second device where a bonding electrode bonded to the plated bump is disposed; and a sealing layer made of NCF or NCP, the sealing layer being disposed between the first device and the second device and including filler particles made of inorganic material; wherein a surface of the plated bump includes a first area and a second area higher than the first area; and at least a part of a side surface of an outer circumferential portion of the second area intersects with a surface of the first area.