SiC Trench Semiconductor Manufacturing With Measured Etch Depth
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Solution Overview
Problem
Existing methods for manufacturing semiconductor devices using silicon carbide face challenges in controlling the depth of trenches, leading to reduced yield due to inconsistent etching, which affects the placement of the trench bottom within the silicon carbide layers.
Innovation Solution
A method involving precise measurement and control of film thicknesses of silicon carbide layers to determine the depth of trenches accurately, ensuring the trench bottom is positioned correctly within the third silicon carbide layer, thereby improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to form trenches in silicon carbide layers, then the manufacturing process is simple and fast, but the trench depth control is inconsistent leading to reduced yield
Solution Approach 1:
The patent applies preliminary action by measuring the film thickness of silicon carbide layers before the etching process. The control unit receives thickness information from measurement units and calculates the required etching depth in advance, ensuring precise trench depth control before the actual etching occurs. This pre-measurement and pre-calculation approach resolves the depth control inconsistency without adding complex real-time control during etching.
Solution Approach 2:
The patent implements feedback control by using measurement units to detect the actual film thickness of silicon carbide layers, then feeding this information back to the control unit. The control unit adjusts the etching depth based on this feedback, creating a closed-loop control system that ensures consistent trench depth despite variations in layer thickness, thereby improving manufacturing precision.
2Manufacturing precision
If precise measurement and control of film thickness are implemented, then trench depth placement accuracy improves, but the manufacturing process becomes more complex
Solution Approach 1:
The system applies self-service by automatically measuring film thickness and calculating etching depth without requiring manual intervention. The measurement units and control unit work autonomously to determine the precise trench depth based on actual layer thickness, reducing the need for complex manual measurement and control procedures while maintaining high precision.
Solution Approach 2:
The patent replaces manual mechanical measurement and control methods with automated measurement units and electronic control systems. This substitution eliminates the need for complex manual operations while achieving precise trench depth placement, thereby improving ease of manufacture despite the added measurement and control capabilities.
3Productivity
If inconsistent etching depth is produced, then manufacturing speed is maintained, but yield decreases due to defective device placement
Solution Approach 1:
By measuring film thickness before etching and calculating the precise etching depth in advance, the system ensures consistent trench depth control. This preliminary measurement and calculation step prevents etching inconsistencies that would otherwise reduce yield, while maintaining manufacturing speed through automated processing.
Solution Approach 2:
The feedback control mechanism uses actual film thickness measurements to adjust etching depth, ensuring consistent results. This closed-loop control improves manufacturing yield by eliminating defective device placement caused by inconsistent etching, while the automated nature of the feedback process maintains high productivity.
Data Source
AI summary
A method of an embodiment includes: forming, in a first region of an upper surface of a first-conductivity-type first silicon carbide layer, a second silicon carbide layer having a first-conductivity-type impurity concentration different from that of the first silicon carbide layer and having a first film thickness D2; forming a second-conductivity-type third silicon carbide layer having a film thickness D4 in a second region of the upper surface; forming, on the first silicon carbide layer, a fourth silicon carbide layer having a lower first-conductivity-type impurity concentration than the second silicon carbide layer and having a film thickness D1; measuring a second film thickness D3 of the second silicon carbide layer and the film thickness D1 of the fourth silicon carbide layer; and forming a trench penetrating the fourth silicon carbide layer to reach the third silicon carbide layer based on the film thickness D1, D2, D3, D4.