Small Outline Transistor Thermal Flat Lead Design
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Solution Overview
Problem
Small outline transistors face thermal performance issues in high voltage switching applications due to thermal effects, and existing solutions that improve thermal performance, such as exposed thermal pads, increase production costs and complexity.
Innovation Solution
The electronic device features a die attach pad with tie bars and leads that provide mold locking features and improved thermal dissipation, using a lead frame panel array with down set tie bars and leads to enclose and expose portions of the die attach pad, allowing for efficient heat removal and reduced production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If exposed thermal pads are used to improve thermal performance, then thermal dissipation is enhanced, but production costs increase due to expensive materials and complex processes
Solution Approach 1:
The lead frame structure serves multiple functions: it provides mechanical support, electrical connection, and thermal dissipation pathways. The tie bars and leads collectively function as both structural elements and thermal conduction paths, eliminating the need for separate expensive thermal management components.
Solution Approach 2:
The lead frame structure itself provides the thermal dissipation function through its inherent metallic conductivity and geometric configuration. The tie bars and leads naturally conduct heat away from the die attach pad without requiring additional thermal management components or processes.
2Temperature
If exposed thermal pads are used to improve thermal performance, then heat dissipation is enhanced, but device complexity increases due to dedicated mold tools and single unit molds
Solution Approach 1:
The patent combines multiple functions into the lead frame structure: mechanical support, electrical connection, and thermal dissipation. The tie bars and leads are integrated into a single continuous structure that performs all these functions simultaneously, reducing the need for separate components and complex assembly processes.
Solution Approach 2:
The lead frame serves as a multi-functional component that provides structural support, electrical pathways, and thermal conduction. This universal approach allows standard molding processes to produce devices with effective thermal management without requiring dedicated complex mold tools.
3Stability of the object's composition
If expensive low density etched lead frame strips are used to create mold locking features, then mold locking is achieved, but production costs increase
Solution Approach 1:
The lead frame is divided into functional segments: tie bars that provide structural support and thermal pathways, and leads that provide electrical connections. This segmentation allows each element to be optimized for its specific function while using cost-effective standard lead frame materials and processes.
Solution Approach 2:
The patent uses standard, cost-effective lead frame materials and processes to create the tie bar structure. Rather than using expensive specialized materials, the solution relies on conventional lead frame technology that is already widely available and economically proven in the industry.
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 configuration enhances thermal performance and reliability of small outline transistors by mitigating mold delamination and over mold occurrences, while maintaining cost-effectiveness through concurrent manufacturing of high-density arrays using low-cost processes.
Implementation Method 1
the package structure exposes a portion of the first side of the die attach pad
Data Source
AI summary
An electronic device includes a die attach pad, a semiconductor die, a lead, a package structure, and tie bars, where the die attach pad has opposite first and second sides, the semiconductor die is attached to the second side of the die attach pad, the lead has a first portion connected to a circuit of the semiconductor die by a bond wire, the package structure exposes a portion of the first side of the die attach pad and the second portion of the lead. Four tie bars extend outward from the die attach pad and the tie bars have respective ends exposed outside the package structure.