GaN/SiC Semiconductor Device With Diamond Thermal Management
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Solution Overview
Problem
Current semiconductor devices for RF applications, particularly those using gallium nitride (GaN) and silicon carbide (SiC) materials, face challenges in heat dissipation and mechanical strength, especially when using thicker diamond and thinner SiC substrates, which are difficult to process and fragile, and wire bonding processes hinder high-frequency device performance.
Innovation Solution
A semiconductor device and manufacturing method involving the formation of high-electron mobility transistors on a GaN/SiC substrate, followed by bonding with a diamond wafer using metal bump connectors and resin material layers, with laser cutting to create individual devices, enhancing thermal and mechanical properties while improving bonding and handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thicker diamond and thinner SiC wafer substrates are used to improve heat dissipation and mechanical strength, then thermal conductivity and device strength are improved, but processing difficulty and fragility increase
Solution Approach 1:
The patent performs preliminary actions by forming through-holes and depositing metal layers on the diamond wafer before bonding, and preparing the GaN/SiC structure with bonding pads in advance. This allows the fragile thin SiC substrate to be processed and bonded without requiring post-bonding modifications that would be difficult on such a thin substrate.
Solution Approach 2:
The patent introduces an intermediary approach by using a wafer bonding process that joins the diamond wafer to the GaN/SiC structure at controlled temperatures and pressures, with metal layers serving as intermediaries for both thermal management and electrical connections, thereby enabling the integration of thin fragile substrates with thicker support structures.
2Temperature
If thinner SiC wafer substrates are used to improve thermal properties, then heat dissipation is improved, but mechanical strength and handling robustness decrease
Solution Approach 1:
The patent creates a composite structure by bonding the thin SiC wafer with GaN layers and metal interconnects to the diamond substrate. This composite construction allows the thin SiC layer to provide excellent thermal properties while the diamond substrate and metal layers provide the necessary mechanical strength and handling robustness.
3Ease of manufacture
If wire bonding processes are used for device interconnection, then manufacturing simplicity is maintained, but high-frequency performance above 10 GHz is limited
Solution Approach 1:
The patent extracts the wire bonding process from the interconnection methodology and replaces it with direct metal layer interconnections formed through through-holes in the diamond wafer. This eliminates the high-inductance wire bonds that limit high-frequency performance while maintaining manufacturing feasibility through 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
This approach enables effective heat dissipation and mechanical strength improvements, facilitating high-frequency operation by integrating GaN/SiC HEMTs with diamond wafers, addressing processing and fragility issues, and enhancing device performance beyond 10 GHz frequencies.
Implementation Method 1
Diamond has good thermal properties
Implementation Method 2
A second interconnection extends from the first metal pad to the second metal pad
Implementation Method 3
laser cutting to create individual devices
Data Source
AI summary
In one embodiment, a semiconductor device includes a first substrate with a transistor formed in a first active are, a first bonding pad electrically connected to the transistor and a first metal pad surrounding the first active area. A second substrate of a type that is different from the first substrate includes a passive circuit element in a second active area on a front surface, a second bonding pad electrically connected to the passive circuit element, a second metal pad surrounding the second active area, and a mounting pad on a back surface of the second substrate with a through-via electrically connecting the second bonding pad to the mounting pad. A first interconnection extends from the first bonding pad to the second bonding pad, and a second interconnection extends from the first metal pad to the second metal pad and surrounds the region through which the first interconnection extends.