Offset Die Paddle Lead Frame for Higher Package Density
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Solution Overview
Problem
Existing lead frames for semiconductor assemblies are limited in the number of die paddles they can accommodate due to the need for structural rigidity and the resulting waste of material between die paddles.
Innovation Solution
A lead frame design featuring a 2 by n array of die paddles, where the die paddles in one columnar array are offset from those in another, allowing for a reduced sawlane width and increased density of die paddles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If material is removed by etching or stamping to form die paddles, then die paddles are created with structural rigidity, but material waste occurs between adjacent die paddles
Solution Approach 1:
The patent applies asymmetry by offsetting the columnar arrays of die paddles from each other, creating a staggered pattern rather than aligned rows. This asymmetric arrangement allows the saw cuts to pass through the material more efficiently, reducing the width of material that must be removed between die paddles and thereby reducing material waste while maintaining the required number of die paddles.
Solution Approach 2:
The patent transitions from a traditional aligned grid arrangement to a staggered offset arrangement, effectively utilizing spatial optimization in two dimensions. By offsetting columns and adjusting row spacing, the design maximizes the use of available material area, allowing closer packing of die paddles and reducing the waste material between them.
2Ease of manufacture
If material is removed to create individual die paddles, then individual semiconductor assemblies are formed, but the lead frame loses rigidity and may warp or break
Solution Approach 1:
The patent segments the lead frame into individual die paddle units through controlled saw cuts. The offset columnar arrangement allows these cuts to be made more efficiently, separating individual die paddles while maintaining structural integrity during the manufacturing process. The segmentation is achieved in a way that preserves rigidity until the cutting stage.
Solution Approach 2:
The patent applies local quality by maintaining different structural characteristics in different regions of the lead frame. The offset columnar arrangement allows for localized optimization where material is removed only where necessary for individual assembly formation, while preserving material in critical areas to maintain overall rigidity and prevent warping or breaking during manufacturing.
3Quantity of substance
If columnar arrays are aligned, then manufacturing is simplified, but the sawlane width must be larger reducing die paddle density
Solution Approach 1:
The patent employs asymmetry by offsetting the columnar arrays relative to each other, creating a staggered pattern that optimizes the use of available space. This asymmetric arrangement reduces the required sawlane width between columns, thereby increasing die paddle density. The offset arrangement allows saw cuts to pass through material more efficiently, maximizing the number of die paddles that can be produced from a given lead frame size.
Data Source
AI summary
A lead frame for a semiconductor assembly includes a first columnar array of die paddles and a second columnar array of die paddles. The die paddles in the first columnar array are offset from the die paddles in the second columnar array. Each die paddle has a first pad and a second pad. The first pad is larger than the second pad. The first pads in the first columnar array are offset from the first pads in the second columnar array.