Non-Vertical Edge Paddle and Inner Lead IC Package
Solution Overview
Problem
Conventional semiconductor package manufacturing faces challenges in achieving smaller, thinner, and higher I/O integrated circuit packages with reliable connections due to mold flash issues and lead frame deformities, leading to incomplete contact pads and increased manufacturing costs.
Innovation Solution
The integrated circuit package system features a paddle with non-vertical edges and inner leads with non-vertical edges facing the paddle edges, encapsulating an integrated circuit die, which allows for improved alignment and exposure of leads during the molding process, reducing mold flash and ensuring complete contact pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional molding process is used with vertical lead edges, then manufacturing is simpler, but mold flash covers inner lead contacts and prevents reliable PCB connection
Solution Approach 1:
The patent applies asymmetry by changing the lead edges from vertical to non-vertical (angled or tapered) configurations. This asymmetric geometry prevents the molding compound from forming flash over the inner lead contacts, allowing the molding process to proceed without causing connection failures. The non-vertical edges create a geometric constraint that directs the flow of molding material away from the critical contact areas.
Solution Approach 2:
The patent implements preliminary action by pre-forming the non-vertical lead edges before the molding process. This preliminary geometric configuration ensures that when the molding compound is injected, it naturally flows away from the inner lead contacts without requiring additional controls or corrections during the molding operation itself.
2Volume of moving object
If package size is reduced for miniaturization, then portability improves, but manufacturing precision requirements increase due to smaller tolerances
Solution Approach 1:
The non-vertical lead edges create an asymmetric geometry that provides built-in alignment guidance during the molding process. The angled surfaces act as mechanical guides that self-align the leads with the molding cavity, reducing the precision requirements for lead placement. This geometric self-alignment mechanism is particularly valuable in miniaturized packages where traditional high-precision positioning becomes more difficult and expensive.
3Ease of manufacture
If lead frame is etched to reduce material, then cost decreases, but lead deformities increase causing incomplete contact pads
Solution Approach 1:
The non-vertical lead edges create an asymmetric cross-sectional geometry that prevents the thin etched leads from bending or deforming during the molding process. The tapered or angled edges provide structural reinforcement at the critical contact points while maintaining material reduction benefits. This geometric design allows the etched leads to maintain their integrity and form complete contact pads even in high-volume production.
Solution Approach 2:
The patent applies preliminary anti-action by pre-configuring the lead geometry to counteract the deforming forces that occur during molding. The non-vertical edges are designed to resist the compressive and shear forces applied during molding, preventing the leads from bending or lifting before the molding process completes, thereby ensuring complete contact pad formation.
4Stability of the object's composition
If clamping pressure is increased to prevent lead lifting, then lead position stability improves, but mold flash increases covering contact pads
Solution Approach 1:
The non-vertical lead edges create a geometric configuration that is inherently resistant to lifting under clamping pressure. The angled surfaces distribute the clamping force more effectively and create mechanical interlocking that prevents upward movement. This allows the use of standard clamping pressures without generating excessive flash, as the asymmetric geometry naturally resists the lifting tendency that causes flash formation.
Data Source
AI summary
A method of manufacture of an integrated circuit package system includes: forming a paddle, an outer lead, and an inner lead between the paddle and the outer lead; forming a non-vertical paddle edge of the paddle and a non-vertical lead edge of the inner lead facing the non-vertical paddle edge; and encapsulating an integrated circuit die over the paddle.