Low-Cost SOI Structure Without Wafer Bonding
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Solution Overview
Problem
The high cost of semiconductor-on-insulator (SOI) substrates due to the expensive SOI bonding process hinders the widespread adoption of semiconductor devices that benefit from reduced parasitic capacitance and leakage current.
Innovation Solution
A low-cost SOI structure is formed by depositing a metal layer over an insulating layer, eliminating the need for the expensive bonding process, and incorporating a semiconductor device on this structure to achieve similar performance improvements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the traditional SOI bonding process is used to form semiconductor-on-insulator substrates, then performance advantages such as reduced parasitic capacitance and leakage current are achieved, but fabrication cost increases significantly
Solution Approach 1:
The patent replaces the expensive traditional SOI bonding process with a cost-effective alternative using deposited metal layers. The metal layer (e.g., tungsten, copper, or aluminum) is deposited over the insulating layer to create a sacrificial structure that is later removed, leaving the desired SOI structure. This approach uses cheaper materials and processes while achieving the same performance benefits of reduced parasitic capacitance and leakage current.
2Ease of manufacture
If the expensive SOI bonding process is eliminated and replaced with metal layer deposition, then fabrication cost decreases, but structural complexity of the manufacturing process changes
Solution Approach 1:
The patent changes the fundamental parameter of the manufacturing approach by transitioning from a bonding-based process to a deposition-based process. Instead of bonding semiconductor layers to an insulating substrate, the invention deposits metal layers over the insulating layer, then selectively removes portions of the metal layer to form the final SOI structure. This parameter change simplifies the overall manufacturing complexity despite adding deposition steps, as it eliminates the complex bonding process entirely.
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 low-cost SOI structure reduces fabrication costs while maintaining performance advantages such as increased switching speed and reduced leakage current, providing a cost-effective alternative to traditional SOI substrates.
Implementation Method 1
A low-cost SOI structure includes a device layer, an insulating layer, and a metal layer. The metal layer is disposed below the device layer and the insulating layer, such that the insulating layer vertically separates the device layer from the metal layer.
Data Source
AI summary
Various embodiments of the present disclosure are directed towards an integrated chip (IC). The IC includes a substrate. The substrate includes a metal layer, a device layer disposed over the metal layer, and an insulating layer disposed vertically between the metal layer and the device layer. A semiconductor device is disposed on the device layer. An interlayer dielectric (ILD) layer is disposed over the semiconductor device and the substrate.