Wirebondless Semiconductor Module with Hermetic Sealing
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Solution Overview
Problem
Existing semiconductor power modules fail to provide reliable, hermetically sealed solutions for harsh environments, such as high-performance vehicles and aircraft, due to vulnerability to moisture and contaminants, and require complex wire bonds that can malfunction.
Innovation Solution
A sealed semiconductor power module design featuring a substrate with copper bonding, die terminals connected via wirebondless tabs, and a cover made of injection molded conductive polymer with brass inserts, providing direct electrical connections and sealing the module without wires or cables, using materials like AlN, molybdenum, and AlSiC for enhanced reliability and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonds are used to connect electronic circuit areas, then electrical connections can be established, but reliability deteriorates due to susceptibility to malfunction in harsh environments
Solution Approach 1:
The patent removes wire bonds from the connection structure entirely, replacing them with direct tab-to-pad connections. The tabs are directly bonded to the copper bonding pads on the substrate, eliminating the intermediate wire bond component that is susceptible to malfunction in harsh environments.
Solution Approach 2:
The connection structure is merged by directly bonding the tabs to the copper bonding pads on the substrate. This integration eliminates separate wire bond components and creates a more robust, unified connection path that is resistant to environmental degradation.
2Reliability
If the module is left unsealed, then manufacturing is simpler, but reliability deteriorates due to moisture and contaminant infiltration
Solution Approach 1:
The substrate provides localized protection through its copper bonding layers that are directly bonded to the base plate, creating a hermetic seal at the critical connection points. This local quality approach protects the most vulnerable areas without requiring complete module sealing.
Solution Approach 2:
The module employs composite materials including the substrate with copper bonding layers, the base plate, and the cover assembly. These composite structures work together to provide hermetic sealing and environmental protection while maintaining manufacturability.
3Temperature
If copper bonding is directly bonded to the substrate surfaces, then thermal management is improved, but manufacturing precision requirements increase
Solution Approach 1:
The copper bonding layers are pre-formed on the substrate surfaces before the final assembly. This preliminary action allows for precise positioning and bonding of the copper layers to the substrate, ensuring optimal thermal contact while maintaining manufacturing feasibility.
Solution Approach 2:
The copper bonding layers serve as an intermediary between the substrate and the tabs/base plate, providing both electrical connection and thermal management. This intermediate layer facilitates heat transfer while accommodating manufacturing tolerances through its bonding characteristics.
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 offers a reliable, wirebondless, and hermetically sealed semiconductor power module that withstands harsh environments, ensuring high reliability and efficient heat dissipation while eliminating the risk of wire malfunctions, suitable for high-power applications like 600V/150 amps.
Implementation Method 1
the substrate including a copper bonding bonded to one or both of its two major surfaces
Implementation Method 2
a first power terminal is in direct wirebondless electrical connection via a first tab with the main contact area of the first die
Implementation Method 3
seal the module such that a contact portion of the first power terminal, a contact portion of the second power terminal, a contact portion of the third power terminal, and a contact portion of the gate terminal are exposed over a top surface of a top of the cover
Data Source
AI summary
A sealed semiconductor power module that may include a rectifier, such as a silicon controlled rectifier (SCR), is provided. The module includes an AlN substrate having a bottom surface positioned on a metallic base plate and a top surface that includes a first pad and a second pad, the substrate including a copper body on both of the two major surfaces. The module also includes a first die and a second die positioned on top of the first and second pads, respectively, the first die and the second die each including a main contact area on a top surface thereof, the first die including an isolated gate area on the top surface to which is coupled a gate terminal; and first and second power terminals in direct wirebondless electrical connection via molybdenum tabs with the main contact areas of the die.