Molded Standoff for Semiconductor Package Encapsulation
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Solution Overview
Problem
Existing semiconductor package manufacturing techniques fail to provide sufficient clearance beneath the die pad, leading to incomplete mold compound filling, which results in exposed internal structures, humidity issues, and potential failure due to leakage or short circuits.
Innovation Solution
The implementation of a topside-cooled semiconductor package design with a die pad and leads formed from the same conductive material, where the bottom plane of the leads is offset from the die pad, and a molded standoff beneath the die pad extends below the electrical contact plane, enhancing mold compound flow and filling, thus preventing exposure and improving thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the die pad and leads are formed from the same conductive material without offset, then the manufacturing process is simpler, but the mold compound cannot flow completely beneath the die pad, resulting in exposed internal structures and potential failure
Solution Approach 1:
The patent applies asymmetry by offsetting the bottom plane of the leads from the bottom surface of the die pad. This asymmetric configuration creates a standoff that enables mold compound to flow completely beneath the die pad, ensuring proper encapsulation and eliminating exposed internal structures that would compromise reliability.
2Device complexity
If the mold structure is designed without a standoff, then the device complexity is reduced, but the mold compound filling is incomplete, leading to humidity issues and potential leakage
Solution Approach 1:
The patent introduces a vertical dimension element - the molded standoff - that extends downward from the electrical contact plane beneath the die pad. This dimensional feature creates the necessary space for complete mold compound flow and encapsulation without significantly increasing overall device complexity.
3Ease of operation
If the leads are coplanar with the die pad bottom surface, then the electrical contact plane is simplified, but clearance beneath the die pad is insufficient, causing incomplete encapsulation
Solution Approach 1:
The patent segments the lead structure into two distinct sets: a first set of leads connected to the die pad with an offset bottom plane, and a second set of leads with a coplanar bottom plane forming the electrical contact plane. This segmentation allows the offset configuration to provide necessary clearance for mold compound flow while maintaining a simplified coplanar contact surface for electrical connections.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures complete mold compound filling, reduces the risk of humidity-related failures, stabilizes the package on a printed circuit board, and enhances thermal insulation, preventing damage and improving yield.
Implementation Method 1
enhancing mold compound flow and filling
Implementation Method 2
enhances thermal insulation, preventing damage
Data Source
AI summary
A molded semiconductor package arrangement may comprise a die pad configured to support a semiconductor; a set of leads; and a mold structure that is formed to enclose the semiconductor and the die pad within the mold structure. The set of leads and the die pad may be formed from a same piece of conductive material. An electrical contact plane of the set of leads may be offset from a bottom surface of the die pad. The mold structure may include a molded standoff that is beneath the die pad. A bottom surface of the molded standoff may extend below the electrical contact plane of the set of leads by a threshold distance that corresponds to a thickness of the molded standoff.