IC Package Die Pad Relief for Encapsulation Leakage
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Solution Overview
Problem
Current integrated circuit package systems face challenges in encapsulation, including void formation under half-etched bond fingers and bond wires, leading to inefficient heat conduction and mechanical instability, and leakage issues due to increased pressure during encapsulation.
Innovation Solution
A die pad with a relief and a wall around the center pad is used to prevent encapsulation from contaminating the center pad, while a barrier under the bond fingers and wires increases pressure for efficient encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If encapsulation pressure is increased to improve encapsulation efficiency, then encapsulation completeness is improved, but leakage occurs and contaminates the center pad
Solution Approach 1:
The die pad bottom is segmented into a relief area and a center pad area, physically separating the encapsulation zone from the center pad. This segmentation allows high-pressure encapsulation to be applied to the relief area without the encapsulation material flowing onto and contaminating the center pad, thus resolving the contradiction between encapsulation completeness and leakage prevention
Solution Approach 2:
The relief structure acts as an intermediary barrier between the encapsulation material and the center pad. By providing a designated area for encapsulation material to occupy, the relief prevents direct contact between the encapsulation material and the center pad, enabling high-pressure encapsulation without contamination
2Device complexity
If encapsulation is performed without a relief structure, then manufacturing process is simpler, but voids form under bond fingers and wires leading to poor heat conduction and mechanical instability
Solution Approach 1:
The relief structure is pre-formed on the die pad bottom before encapsulation. This preliminary action creates a designated space that guides the encapsulation material to properly fill the area under bond fingers and wires, preventing void formation and ensuring complete encapsulation without requiring complex additional processes
Solution Approach 2:
The relief structure provides localized quality improvement by creating a specific geometric feature on the die pad bottom that ensures proper encapsulation flow and filling. This local modification addresses the specific problem of void formation under bond structures while maintaining overall manufacturing simplicity
Data Source
AI summary
An integrated circuit package system including: providing a die pad with a top, sides, and a bottom, the bottom having a relief with a flat surface and defining a wall and a center pad; mounting a barrier under the bottom of the die pad; mounting an integrated circuit die on the top of the die pad; encapsulating the integrated circuit die and the top and sides of the die pad with the wall preventing encapsulation from flowing along the barrier to reach the center pad; and mounting an external interconnect on the center pad.