SiC Wafer Rear Implant Layer for Optical Substrate Detection
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Solution Overview
Problem
Existing semiconductor wafer technologies face challenges in detecting semi-insulating single crystal SiC substrates using visible light or infrared light due to their high transparency, leading to defective substrate detection during manufacturing processes, especially when metal thin films are scraped off or peeled off, and increasing manufacturing costs.
Innovation Solution
A semiconductor wafer with an impurity implantation layer on the SiC substrate, formed using ion implantation, which has a lower transmittance for visible light or infrared light than the SiC substrate, allowing reliable detection through reflection or absorption of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a semi-insulating single crystal SiC substrate is used for high-frequency devices, then device performance is improved, but substrate detection using visible light or infrared light becomes impossible due to high transparency
Solution Approach 1:
A metal thin film layer is introduced as an intermediary between the transparent SiC substrate and the detection system. This metal layer reflects light back through the substrate, enabling the substrate to become detectable by transmission-type sensors without changing the substrate material itself. The metal film acts as a mediator that converts the transparent substrate into a detectable one while preserving the substrate's electrical properties for high-frequency device performance.
Solution Approach 2:
The invention changes the optical properties of the substrate system by adding a metal thin film that alters light interaction. The metal film reflects specific wavelengths of light, effectively changing the optical characteristics of the otherwise transparent SiC substrate, making it visible to detection sensors without affecting its electrical transparency and performance.
2Difficulty of detecting and measuring
If a metal thin film is formed on the substrate for detection purposes, then substrate detection becomes possible, but the thin film may be scraped off or peeled off during manufacturing processes, causing defective detection
Solution Approach 1:
The metal thin film is formed on the substrate surface before any subsequent manufacturing processes. This preliminary formation ensures the detection layer is in place early in the manufacturing sequence, allowing detection functions to be established before potential mechanical stresses or chemical processes that might cause film removal occur later in the fabrication process.
Solution Approach 2:
The metal thin film serves as a stable intermediary layer that is specifically designed to remain intact during manufacturing processes. By selecting appropriate metal materials and formation methods, the film creates a reliable interface for light reflection that withstands subsequent processing steps, ensuring continuous detection capability throughout manufacturing.
3Ease of operation
If a transmission-type photoelectric sensor is used to detect the substrate, then detection is possible for absorbing substrates like Si or GaAs, but it cannot detect transparent substrates like semi-insulating single crystal SiC
Solution Approach 1:
The metal thin film layer provides universal detection capability that works across different substrate types. By adding this reflective layer, the system can detect both traditionally absorbing substrates (Si, GaAs) and transparent substrates (semi-insulating SiC) using the same transmission-type sensor configuration, thereby extending the versatility of the detection system without requiring multiple specialized sensors.
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 impurity implantation layer enables accurate detection of the SiC substrate using standard manufacturing apparatuses, reducing defective detection and maintaining cost-effectiveness by preventing the layer from being peeled off during processing.
Implementation Method 1
an impurity implantation layer provided on the entire rear surface of the SiC substrate, formed of a same base material as that forming the SiC substrate, including an impurity, and having a lower transmittance of visible light or infrared light than that of the SiC substrate
Implementation Method 2
A method for manufacturing a semiconductor device according to the third invention of the present application includes performing ion implantation into an entire rear surface of a SiC substrate, to form an impurity implantation layer
Data Source
AI summary
A semiconductor wafer device according to the present invention includes a SiC substrate having an upper surface and a rear surface as a surface on the opposite side to the upper surface, and an impurity implantation layer provided on the entire rear surface of the SiC substrate, formed of a same base material as that forming the SiC substrate, including an impurity, and having a lower transmittance of visible light or infrared light than that of the SiC substrate.