Semiconductor Thermal Path Layout for Uniform Transistor Temperature
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Solution Overview
Problem
Temperature variations among parallel-connected unit transistors in a semiconductor apparatus can lead to uneven degradation and reduced lifespan, impairing the characteristics of heterojunction bipolar transistors used in power amplifier modules.
Innovation Solution
A semiconductor apparatus with a substrate, transistor groups, an insulating film, and a metal member, where the insulating film includes cavities and the metal member is electrically connected to the transistors, forming heat transfer paths with varying thermal resistance values to reduce temperature variations among unit transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If parallel-connected unit transistors are arranged to increase current handling capacity, then power output is improved, but temperature variations among transistors increase causing uneven degradation
Solution Approach 1:
The patent applies local quality by creating different thermal environments for different transistors. Specifically, transistors are positioned at different distances from the heat dissipation structure (bump electrode), creating localized thermal characteristics. Transistors closer to the heat dissipation path have lower thermal resistance and better heat dissipation, while those farther away have higher thermal resistance. This intentional local variation in thermal properties balances the temperature rise across all transistors during operation, preventing uneven degradation.
Solution Approach 2:
The patent changes the thermal resistance parameter of heat transfer paths for different transistors. By designing heat transfer paths with different thermal resistance values (Rθ1, Rθ2, Rθ3, etc.), the patent modifies the thermal characteristics of each transistor's heat dissipation path. This parameter variation allows transistors experiencing higher temperature rises to have lower thermal resistance paths, thereby equalizing the operating temperatures across all parallel-connected transistors.
2Ease of manufacture
If uniform heat transfer paths are used for all unit transistors, then manufacturing is simplified, but temperature variations among transistors increase
Solution Approach 1:
The patent implements local quality by designing heat transfer paths with spatially varying thermal resistance. The heat transfer paths are intentionally made different from each other based on their positions relative to the heat dissipation structure. This localized differentiation in thermal path characteristics achieves uniform temperature distribution across transistors while maintaining a relatively simple overall structure that can be manufactured using standard semiconductor fabrication processes.
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
The solution effectively reduces temperature variations among unit transistors by adjusting thermal resistance values, thereby extending the lifespan and maintaining the performance of the semiconductor apparatus.
Implementation Method 1
A heat transfer path is formed by a metal in a region from each of the plural unit transistors to a top surface of the metal member. Thermal resistance values of the heat transfer paths are different from each other among the plural unit transistors.
Data Source
AI summary
A semiconductor apparatus includes a substrate, plural transistor groups disposed on the substrate, an insulating film, and a metal member. Each of the plural transistor groups includes plural unit transistors arranged in a first direction within a plane of a top surface of the substrate. The plural transistor groups are arranged in a second direction perpendicular to the first direction. The insulating film covers the plural unit transistors and includes at least one cavity. The metal member is disposed on the insulating film and is electrically connected to the plural unit transistors via the at least one cavity. A heat transfer path is formed by a metal in a region from each of the plural unit transistors to a top surface of the metal member. Thermal resistance values of the heat transfer paths are different from each other among the plural unit transistors.