Semiconductor Package Retaining Wall Glue Containment
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Solution Overview
Problem
Current package structures for high electron mobility transistors (HEMT) devices face instability due to glue overflow, affecting device operation and reliability, and lack effective prevention of electromagnetic interference (EMI).
Innovation Solution
A package structure featuring a die pad with a retaining wall structure and conductive glue, where the glue is confined within the retaining wall to prevent overflow and ensure electrical grounding, enhancing operational stability and preventing EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional die mounting technique is used, then the package structure is simple, but glue overflow becomes unstable and adversely affects device operation
Solution Approach 1:
The die pad is segmented into a mounting surface and a retaining wall structure. The retaining wall is formed as a separate structural element that rises from the mounting surface, creating distinct functional zones: one for die attachment and another for glue containment. This segmentation allows the glue to be confined within the retaining wall boundaries, preventing overflow while maintaining a relatively simple overall package structure.
Solution Approach 2:
The retaining wall structure acts as an intermediary element between the die pad and the external environment. It mediates the glue spreading process by providing physical boundaries that contain the glue within the confined region, thereby preventing harmful overflow while allowing the die to be properly mounted and electrically connected.
2Reliability
If glue is allowed to spread freely, then electrical grounding is achieved, but glue overflow occurs and affects device operation
Solution Approach 1:
The retaining wall structure creates localized confinement for the conductive glue. The wall provides different functional qualities in different spatial locations: the mounting surface allows free glue spread for electrical grounding, while the retaining wall region confines the glue to prevent overflow. This local differentiation of functional qualities resolves the contradiction between achieving grounding and preventing overflow.
Solution Approach 2:
The retaining wall structure converts the potentially harmful effect of glue overflow into a beneficial containment mechanism. By providing defined boundaries, the wall ensures that the glue remains in the desired location, transforming what could be a manufacturing defect (overflow) into a controlled feature that enhances reliability through consistent glue placement and electrical connection.
3Reliability
If retaining wall structure is added, then glue overflow is prevented, but device complexity increases
Solution Approach 1:
The retaining wall structure is merged with the die pad to form an integrated lead frame component. Rather than adding a separate, complex containment structure, the retaining wall is formed as part of the existing die pad geometry, rising from its mounting surface. This merging approach prevents glue overflow while minimizing the increase in overall device complexity.
Solution Approach 2:
The die pad is designed to serve multiple functions: it provides a mounting surface for die attachment, an electrical connection path, and through the integrated retaining wall, a glue containment structure. This multi-functionality reduces the need for additional separate components, thereby preventing glue overflow without significantly increasing device complexity.
Data Source
AI summary
A package structure is provided. The package structure includes a die, a lead frame, and a conductive glue. The lead frame includes a die pad and a retaining wall structure. The die pad is configured to support the die, and the retaining wall structure surrounds the die. The conductive glue is disposed between the die and the lead frame.