Micro Bump Structure Fabrication Using Solder Ball Grinding
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Solution Overview
Problem
The need for miniaturization in electronic devices requires the fabrication of smaller electrical and conducting components, but existing methods for creating micro bump structures are costly, necessitating a low-cost manufacturing method for micro bump structures using solder balls.
Innovation Solution
A manufacturing method involving the formation of an under bump metallurgy (UBM) layer on a substrate, followed by the placement and grinding of a solder ball to a predetermined height, with optional use of a buffer or release layer to form a micro bump structure, allowing for the creation of a micro bump structure using an inexpensive solder ball.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional micro bump fabrication methods are used, then micro bump structures can be formed, but the manufacturing cost is high
Solution Approach 1:
The patent uses inexpensive solder balls as disposable objects to create micro bump structures. The solder balls are placed on the substrate, connected to UBM layers, and then the entire assembly is grinded to form the final micro bump structure. This approach replaces expensive traditional micro bump fabrication processes with a low-cost solder ball-based method.
Solution Approach 2:
The patent changes the physical state and dimensions of solder balls through grinding to transform them into micro bump structures with precise height control. By controlling the grinding depth and using release layers, the method achieves the required manufacturing precision for micro bump structures while maintaining low material costs.
2Volume of moving object
If solder ball height is reduced through grinding, then miniaturized components are formed, but additional processing steps are required
Solution Approach 1:
The patent performs preliminary actions by placing release layers on the substrate before positioning the solder balls. These release layers facilitate easier solder ball placement and subsequent grinding operations. The UBM layers are also prepared in advance on the substrate, enabling streamlined processing and reducing overall device complexity despite the additional grinding step.
Solution Approach 2:
The patent introduces release layers as intermediary elements between the substrate and solder balls. These release layers serve as temporary carriers that enable precise solder ball positioning and facilitate the grinding process. After the micro bump structure is formed, the release layers are removed, having served their intermediary function.
3Ease of manufacture
If normal size solder balls are used, then material cost is reduced, but component miniaturization is limited
Solution Approach 1:
The patent addresses the size limitation by applying dimensional transformation through grinding. Normal-sized solder balls are placed on the substrate and then grinded to reduce their height, transforming them into miniaturized micro bump structures. This dimensional change in the vertical dimension enables miniaturization while maintaining the use of cost-effective normal-sized solder balls.
Solution Approach 2:
The patent changes the physical parameters of solder balls by controlling the grinding depth to achieve the desired height reduction. By precisely controlling the grinding process and using release layers as depth references, the method transforms normal-sized solder balls into miniaturized components with controlled dimensions, achieving both cost reduction and miniaturization.
Data Source
AI summary
A manufacturing method for a micro bump structure includes the following steps as follows. A substrate is provided and a under bump metallurgy (UBM) is formed on the substrate for accommodating a solder ball. A buffer layer is disposed on the substrate and then the solder ball is disposed on the UBM. Finally, the solder ball is grinded in order get the height reduced to a predetermined height.