Die Package Clip Positioning to Maximize Chip Area
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Solution Overview
Problem
Die packages without tie bars face challenges in maximizing chip size due to pin positioning constraints, leading to potential die damage from tight tolerances and pin-die contact.
Innovation Solution
A method involving a stack of die pad, die, and clip is pressed with pins on the clip's top surface during molding, using retractable or fixed pins to secure the stack, allowing for increased design freedom and minimizing die pad space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pin is used to secure the die pad position during molding, then the die pad positioning is secured, but the pin occupies space on the die pad reducing the maximum chip size
Solution Approach 1:
The patent introduces a clip as an intermediary component between the pin and the die pad. The pin contacts the clip instead of directly contacting the die pad, allowing the die pad positioning to be secured while eliminating pin contact with the die pad surface, thereby maximizing chip area without compromising positioning accuracy
2Area of moving object
If the separation between pin position and die edge is made tight to maximize chip size, then more space is available for the chip, but pin positioning tolerance may cause pin-die contact leading to die chipping
Solution Approach 1:
The clip serves as a protective intermediary that decouples the pin positioning system from the die pad. This allows tight spacing between pin position and die edge to be maintained for maximizing chip area, while the clip absorbs positioning tolerances and prevents direct pin-die contact that would cause chipping
Solution Approach 2:
The clip acts as a cushioning element positioned beforehand between the pin and die pad. It provides a compliance layer that accommodates positioning variations and prevents harmful contact forces from reaching the die, thereby protecting die integrity before contact can occur
Data Source
AI summary
A method of forming a die package is provided. The method may include arranging a stack including a die pad, a die, and a clip in a molding cavity, and, at least during an initial phase of filling the molding cavity with molding material, pressing the stack towards a bottom of the molding cavity with at least one pin contacting a top surface of the clip.