Lead-Free Glass Layer for High-Temperature Reverse Bias Resistance
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Solution Overview
Problem
Conventional mesa-type semiconductor elements in resin-sealed semiconductor devices exhibit reduced resistance to reverse bias at high temperatures due to lead-containing glass layers, which induce high ion concentrations and increase leakage current.
Innovation Solution
Employing a glass layer made of lead-free glass with a lower dielectric constant, composed of specific components such as SiO2, B2O3, Al2O3, ZnO, and alkaline earth metal oxides, to prevent ion induction and reduce leakage current during high-temperature reverse bias tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lead-containing glass is used, then the glass layer provides adequate protection, but ions are induced at interfaces during high-temperature reverse bias testing which forms leakage channels
Solution Approach 1:
The patent modifies the glass composition parameters to eliminate lead oxide and replace it with oxides that have lower dielectric constants and reduced ion-inducing properties. This parameter change prevents the formation of high-concentration ion regions at interfaces during high-temperature reverse bias testing.
2Ease of manufacture
If conventional glass composition is used, then manufacturing is straightforward, but the device exhibits reduced resistance to reverse bias at high temperatures
Solution Approach 1:
The patent uses a composite glass composition with multiple oxide components that can be manufactured using conventional glass fabrication techniques. The composite nature provides the necessary electrical properties for high-temperature performance while maintaining compatibility with existing manufacturing 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 use of lead-free glass layers enhances the resistance to reverse bias at high temperatures in resin-sealed semiconductor devices, maintaining device integrity and performance comparable to or exceeding that of conventional devices while minimizing leakage current.
Implementation Method 1
lead-free glass (glass which contains no Pb) composition having a lower dielectric constant than lead-containing glass
Data Source
Figure 1A~1C
Figure 2~3B
Figure 4A~4D
AI summary
A resin-sealed semiconductor device 10 of the present invention includes : a mesa-type semiconductor element 100 which includes a mesa-type semiconductor base body having a pn-junction exposure portion in an outer peripheral tapered region which surrounds a mesa region, and a glass layer which covers at least the outer peripheral tapered region; and a molding resin 40 which seals the mesa-type semiconductor element 100, wherein the mesa-type semiconductor element 100 includes a glass layer which substantially contains no Pb as the glass layer. The resin-sealed semiconductor device of the present invention can acquire higher resistance to a reverse bias at a high temperature than a conventional resin-sealed semiconductor device, although the resin-sealed semiconductor device of the present invention has the structure where the mesa-type semiconductor element is molded with a resin in the same manner as the conventional resin-sealed semiconductor device.