Parallel Bipolar Transistor Layout for Flip-Chip Breakdown Resistance
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Solution Overview
Problem
Existing semiconductor devices with bipolar transistors experience temperature nonuniformity and breakdown issues when using flip-chip mounting, as the heat dissipation path does not pass through the substrate, leading to degraded breakdown resistance.
Innovation Solution
A semiconductor device design with bipolar transistors connected in parallel, featuring a conductive projection that overlaps and is electrically connected to the emitter electrodes, and a through-via with a wider inward portion to enhance heat transfer and reduce thermal resistance, particularly in cells other than those at the ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flip-chip mounting is employed, then mounting efficiency and electrical connection are improved, but heat dissipation capability deteriorates because the heat dissipation path does not pass through the substrate
Solution Approach 1:
The patent applies local quality by creating asymmetric collector layer widths specifically for intermediate bipolar transistors (those not at the ends). The intermediate transistors have wider collector layers than the end transistors, allowing tailored heat dissipation paths for different positional requirements. This local differentiation enables effective heat management in flip-chip mounting where substrate heat dissipation is unavailable.
2Ease of manufacture
If uniform collector layer width is used for all bipolar transistors, then manufacturing simplicity is maintained, but temperature uniformity deteriorates in intermediate transistors
Solution Approach 1:
The patent implements local quality by differentiating collector layer widths based on transistor position. Intermediate bipolar transistors (those not at the array ends) are given wider collector layers to enhance their heat dissipation capability, while end transistors maintain narrower widths. This positional differentiation compensates for the reduced heat dissipation efficiency in flip-chip mounting configurations.
Solution Approach 2:
The patent applies parameter changes by modifying the collector layer width parameter specifically for intermediate bipolar transistors. The collector layer width is increased for intermediate devices compared to end devices, creating a parameter variation that optimizes heat dissipation across the transistor array while maintaining overall manufacturing feasibility.
3Temperature
If intermediate bipolar transistors have wider collector layers, then heat dissipation from substrate is enhanced, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating asymmetric collector layer widths specifically for intermediate bipolar transistors (those not at the ends). The intermediate transistors have wider collector layers than the end transistors, allowing tailored heat dissipation paths for different positional requirements. This local differentiation enables effective heat management in flip-chip mounting where substrate heat dissipation is unavailable.
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 improves the breakdown resistance of the semiconductor device by regulating temperature rises and enhancing heat dissipation, thereby reducing the deterioration of breakdown resistance across the device, even when flip-chip mounting is employed.
Implementation Method 1
the width of an inward portion of a through-via separated from both ends of the through-via in the first direction is wider than the widths of portions at both ends of the through-via in the first direction. The thermal resistance of a heat transfer path via the through-via is lowered in a region other than both ends of the through-via in the first direction
Data Source
AI summary
In a semiconductor device, plural cells are disposed side by side on a substrate in a first direction. Each of the plural cells includes a bipolar transistor, an emitter electrode contained in a base layer of the bipolar transistor as viewed from above, and a base electrode. The bipolar transistors of the plural cells are connected in parallel with each other. Among the plural cells, the breakdown resistance of at least one second cell, which is other than a first cell disposed at each end, is higher than that of the first cell. It is possible to provide a semiconductor device that can reduce the deterioration of the breakdown resistance when flip-chip mounting is employed, as well as when face-up mounting is employed.