Solder Ball Placement Using Segmented Mask System
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Solution Overview
Problem
Existing methods for forming solder connection portions of different diameters on semiconductor chips face challenges in precision and cost due to difficulties in sorting and placing solder balls of varying sizes, leading to increased production costs and potential mounting errors.
Innovation Solution
A method involving a base mask with distinct opening portions for different electrode pads and successive arrangement of masks to accurately place and melt solder balls of varying diameters, ensuring reliable placement and preventing mixing or misplacement of solder balls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If solder balls of different diameters are placed on opening portions using a single mask, then solder connection portions of different sizes can be formed, but it becomes difficult to sort out and reuse the collected solder balls, increasing production cost
Solution Approach 1:
The patent divides the mask into multiple separate masks, each having opening portions of a specific diameter. This segmentation allows solder balls of different diameters to be placed separately on different masks, and when collected, they can be easily sorted and reused by simply selecting from the respective diameter-specific masks without complex sorting processes.
2Adaptability or versatility
If solder balls with small difference in diameters are placed on opening portions, then various sizes of solder connection portions can be formed, but solder balls may be placed on wrong opening portions, reducing mounting precision
Solution Approach 1:
Each mask is designed with opening portions having specific diameters that correspond to specific electrode pad sizes. This local quality differentiation ensures that solder balls of appropriate diameters are placed only on masks with matching opening sizes, preventing misplacement even when diameter differences are small, thereby maintaining high mounting precision.
3Ease of manufacture
If printing method is used to form solder bumps, then the process is simple, but it becomes difficult to form solder bumps when pitches become narrow
Solution Approach 1:
The patent introduces masks as intermediary tools between the solder ball supply and the electrode pads. These masks with precisely controlled opening portions enable accurate placement of solder balls at narrow pitches by physically guiding the solder balls to the correct positions, overcoming the limitations of the printing method while maintaining process simplicity.
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
This approach allows for the efficient and reliable formation of solder connection portions of different diameters on electrode pads, improving mounting precision and reducing production costs by ensuring accurate placement and easy reuse of solder balls.
Implementation Method 1
a third step of melting the solder balls
Data Source
AI summary
A method of forming solder connection portions on first electrode pads and on second electrode pads, comprises a first step of arranging solder balls on the first electrode pads by arranging a first mask on a base mask; a second step of arranging solder balls on the second electrode pads by arranging a second mask on the base mask; and a third step of melting the solder balls. The base mask has first opening portions corresponding to the first electrode pads and second opening portions corresponding to the second electrode pads and having a size different from that of the first opening portions. The first mask has opening portions corresponding to the first opening portions and covering the second opening portions. The second mask has opening portions corresponding to the second opening portions and covers the first opening portions.