Columnar Electrode Through-Holes for Solder Ball Adhesion
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Solution Overview
Problem
Conventional semiconductor devices with wafer level Chip Scale Package (CSP) structures experience poor adhesion and detachment of solder balls from columnar electrodes due to small contact areas, leading to packaging failures under external forces.
Innovation Solution
The semiconductor device incorporates a columnar electrode with through-holes and a solder ball having a convex metal head and filling parts that fill the through-holes, forming a bolt-like structure, increasing the contact area and adhesion between the solder ball and the columnar electrode, enhancing its ability to withstand external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional solder ball is used on a columnar electrode, then the structure is simple, but the adhesion is poor and the solder ball easily detaches under external forces
Solution Approach 1:
The columnar electrode is segmented by introducing through-holes that divide the bulk material into multiple regions. This segmentation increases the surface area and creates multiple bonding interfaces between the solder ball and the electrode, significantly improving adhesion while maintaining a relatively simple overall structure.
Solution Approach 2:
The invention transitions from a conventional surface-only contact between solder ball and electrode to a three-dimensional contact structure. The through-holes create internal bonding surfaces, transforming the adhesion from a two-dimensional interface to a multi-dimensional network of bonding surfaces, thereby enhancing mechanical strength and reliability.
2Reliability
If the contact area between solder ball and columnar electrode is increased, then the adhesion improves, but the manufacturing process becomes more complex
Solution Approach 1:
The through-holes are formed in the columnar electrode before the solder ball is attached. This preliminary action prepares the bonding structure in advance, allowing the solder ball to naturally fill and bond with the pre-formed holes during the attachment process, thereby simplifying the overall manufacturing sequence despite the added structural complexity.
Solution Approach 2:
The columnar electrode is designed with a porous structure containing through-holes. This porous architecture increases the effective contact area and surface roughness, enhancing mechanical interlocking and adhesion between the solder ball and electrode. The porous structure can be fabricated using standard semiconductor processing techniques, maintaining ease of manufacture.
Data Source
AI summary
Semiconductor devices and methods are provided. The semiconductor device can include a semiconductor substrate, a plurality of solder pads disposed on the semiconductor substrate, a first insulating layer disposed over the semiconductor substrate, a columnar electrode disposed over the solder pad, and a solder ball disposed on the columnar electrode. The first insulating layer can include a first opening to expose a solder pad of the plurality of solder pads. The columnar electrode can include a bulk material and a through hole in the bulk material. The through hole can expose at least a surface portion of the solder pad. The solder ball can include a convex metal head on a top surface of the bulk material of the columnar electrode, and a filling part filled in the through hole.