Lead Frame Corner Geometry for UV Tape Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the quad flat no-lead (QFN) package, the insufficient contact areas between the lead frame's corners and UV tape lead to the sides of the unit flying off during cutting, potentially damaging the cutting blade and chip, necessitating additional UV tape application to prevent this issue, increasing operational costs and time.
Innovation Solution
A lead frame with units arranged in a matrix pattern, featuring outwardly extending corners that form attaching portions for UV tape attachment, increasing the contact area and mold area to prevent sides from flying off during cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lead frame uses traditional square units with right-angled corners, then the manufacturing process is simple, but the contact area between the sides and UV tape is insufficient causing sides to fly off during cutting
Solution Approach 1:
The patent applies asymmetry by changing the corner geometry from right-angled to rounded corners. This asymmetric modification increases the contact area between the lead frame sides and UV tape, preventing sides from flying off during high-speed cutting while maintaining overall structural simplicity.
2Reliability
If additional UV tape is applied to corner sides to prevent flying off, then the cutting stability improves, but the operation time, manpower and material costs increase
Solution Approach 1:
The patent implements self-service by designing the lead frame structure itself to provide sufficient UV tape attachment area through rounded corners. This eliminates the need for additional UV tape application operations, allowing the structure to solve its own stability problem without external intervention.
3Area of stationary object
If the contact area between sides and UV tape is increased, then the sides remain stable during cutting, but the traditional square corner design cannot achieve this without structural modification
Solution Approach 1:
The patent applies spheroidality by rounding the corners of the lead frame units. This curved geometry naturally increases the surface area available for UV tape attachment compared to sharp right-angled corners, providing better adhesion and stability during cutting without requiring complex additional structures.
Data Source
AI summary
A lead frame for a quad flat no-lead package includes a plurality of units arranged in a matrix manner and each having four comers. Each of the corners extends outwards to define an attaching portion for attachment to a UV tape such that four sides of each of the units won't fly off when the sides are cut off.