Low Profile Semiconductor Package Vacuum Die Securing
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Solution Overview
Problem
The increasing demand for smaller, more functional electronic systems with lower voltage and higher power consumption is hindered by the large size of multiple power switching transistors on motherboards, which occupy valuable space and have poor yields due to inadequate die securing during wirebonding.
Innovation Solution
A semiconductor device with a low profile package design, where semiconductor dice are mounted on a leadframe matrix with a mounting tape and secured using a vacuum system during wirebonding, eliminating the need for a die attach pad and reducing thermal and electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wirebonding is performed without mounting dice on die attach flags, then the package structure is simplified, but the yield deteriorates due to poor die positioning security
Solution Approach 1:
The mounting tape with vacuum holes is prepared in advance during leadframe fabrication, creating a positioning system that secures dice before wirebonding begins. This preliminary positioning structure ensures die stability during the wirebonding process without requiring complex die attach flags.
2Power
If multiple power switching transistors are used to meet high current levels, then the power consumption requirement is satisfied, but the area occupied on the motherboard increases
Solution Approach 1:
Multiple power switching transistors are combined into a single integrated power module package. This consolidation integrates multiple transistor dice within one compact package, enabling high current handling while occupying minimal motherboard space.
3Volume of moving object
If a low profile package design is implemented, then the physical size is reduced, but the thermal management becomes more challenging
Solution Approach 1:
The mounting tape is removed after wirebonding, exposing the bottom surface of the semiconductor die. This extraction of the temporary mounting structure creates a direct thermal path from the die to the external environment, improving heat dissipation in the compact low-profile package.
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 achieves a smaller footprint, higher reliability, and lower costs by reducing on-resistance and thermal resistance, allowing for more efficient power management and reduced internal stresses due to fewer dissimilar materials and metallurgical junctions.
Implementation Method 1
The semiconductor die is secured during package assembly by positioning over a hole in the mounting tape and applying a vacuum through the hole
Data Source
AI summary
A semiconductor device (10) is made by mounting the bottom surfaces (31, 44, 54) of a semiconductor die (14) and a lead (15, 17) on a tape (12) and over a hole (19) in the tape. A vacuum is drawn through the hole to secure the die in place when the lead's top surface (43) is wirebonded to a top surface (32) of the semiconductor die. A molding material (49) is formed to encapsulate the top surface of the semiconductor die and to expose its bottom surface.