Tie Bar Segmentation for Semiconductor Lead Frame Holding and Cutting
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Solution Overview
Problem
The challenge lies in finding a balance between easily fixing and cutting a tie bar in a lead frame, where a large tie bar width is necessary for holding but a small width is required for easy cutting, making it difficult to achieve both effectively.
Innovation Solution
A lead frame design featuring a tie bar with alternating narrow-width sections and a wide-width section with a through-hole, allowing for easy holding with a jig and efficient cutting by enabling precise removal of resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large tie bar width is used, then the tie bar can be easily held with a holding jig, but it becomes difficult to cut the tie bar
Solution Approach 1:
The tie bar is segmented into different width sections: a wide-width section for holding and narrow-width sections for cutting. This segmentation allows each section to serve its specific function optimally - the wide section provides sufficient surface area for the holding jig to grip, while the narrow sections are easily cut by cutting tools.
Solution Approach 2:
Different sections of the tie bar have different local qualities (widths) tailored to their specific functions. The wide-width section has larger dimensions optimized for holding operations, while the narrow-width sections have smaller dimensions optimized for cutting operations. This local differentiation resolves the contradiction between ease of holding and ease of cutting.
2Ease of manufacture
If a small tie bar width is used, then the tie bar can be easily cut, but it becomes difficult to hold with a holding jig
Solution Approach 1:
The tie bar is divided into functional segments where the wide-width section specifically addresses the holding requirement while narrow-width sections address the cutting requirement. This segmentation allows the tie bar to overcome the limitation of small overall width by providing a localized wide section for jig engagement.
Solution Approach 2:
The tie bar features local quality variation with a wide-width section providing enhanced gripping surface for the holding jig, while maintaining narrow-width sections for easy cutting. This local differentiation enables the tie bar to satisfy both holding and cutting requirements despite the overall compact design.
3Object-generated harmful factors
If unnecessary resin is removed by pushing with a break pin, then the runner can be flicked away, but the process becomes complex without proper tie bar fixation
Solution Approach 1:
The tie bar is pre-designed with a wide-width section that facilitates preliminary fixation with the holding jig before the resin removal operation. This preliminary structural design simplifies the subsequent runner pushing and flicking away process by ensuring stable fixation is easily achieved.
Solution Approach 2:
The wide-width section of the tie bar acts as an intermediary element between the holding jig and the narrow-width sections. It provides a stable fixation point that enables the breaker pin to effectively push and remove the runner without requiring complex fixation mechanisms.
Data Source
AI summary
A first lead terminal, a second lead terminal provided parallel to the first lead terminal, and a tie bar connecting the first lead terminal and the second lead terminal are provided. The tie bar includes a first narrow-width section touching the first lead terminal, a second narrow-width section touching the second lead terminal, and a wide-width section having a larger width than the first narrow-width section and the second narrow-width section and connecting the first narrow-width section and the second narrow-width section. The wide-width section has a through-hole formed between the first narrow-width section and the second narrow-width section.