SiC Groove Depth Adjustment for Simultaneous Trench Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing silicon carbide (SiC) semiconductor devices lies in simultaneously adjusting the depths of trenches and mesa-grooves without the loading effect, which is difficult due to narrow dry etching conditions, leading to increased manufacturing costs and inefficiencies.
Innovation Solution
A method involving preparing masks with different thicknesses on SiC substrates to form openings of varying widths, allowing for simultaneous etching of trenches and mesa-grooves to achieve a desired depth ratio, thereby reducing the need for multiple etching-mask forming processes and lowering manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual etching processes are executed for trenches and mesa-groove to adjust respective depths, then manufacturing precision is improved, but device complexity and manufacturing cost increase due to requiring two separate etching-mask forming processes
Solution Approach 1:
The mask structure is segmented into multiple layers with different thicknesses. A first mask layer with first thickness is formed for trench etching, and a second mask layer with second thickness is formed for mesa-groove etching. This segmentation allows each layer to control the etching depth of different structures independently, achieving precise depth control while using a single integrated mask forming process rather than two separate processes.
2Productivity
If simultaneous etching of trenches and mesa-groove is executed, then productivity is improved, but manufacturing precision deteriorates due to loading effect causing different etching depths
Solution Approach 1:
Different regions of the mask have different local qualities in terms of thickness. The first mask layer has a first thickness in the trench region and a second thickness in the mesa-groove region. This local variation in mask thickness compensates for the loading effect during simultaneous etching, allowing both trenches and mesa-groove to reach their target depths uniformly despite the different etching conditions in each region.
3Manufacturing precision
If narrow dry etching conditions are used for SiC trench etching, then manufacturing precision is improved, but ease of manufacture deteriorates due to difficulty in suppressing loading effect
Solution Approach 1:
The multi-layer mask structure acts as an intermediary that mediates between the trench etching and mesa-groove etching processes. By carefully designing the thicknesses of the first and second mask layers, the system can maintain narrow etching conditions for precise trench formation while the mask thickness difference compensates for the loading effect, making the overall process easier to manufacture without requiring extreme process condition optimization.
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 the simultaneous etching of trenches and mesa-grooves to comparable depths, reducing the number of exposure masks and process man-hours, thus lowering the cost of semiconductor device production while maintaining the required depth ratios.
Implementation Method 1
forming a first groove and a second groove in each of the substrates by selectively etching via the first opening and the second opening
Data Source
AI summary
The method for adjusting a groove depth includes: preparing masks having different thicknesses on respective top surfaces of a plurality of substrates made of silicon carbide; forming a first opening having a predetermined width and a second opening having a width wider than the first opening in each of the masks; simultaneously forming a first groove and a second groove in each of the substrates by selectively etching via the first opening and the second opening; measuring a depth ratio of the first groove to the second groove in each of the substrates; and acquiring a thickness of a mask such that the depth ratio is an intended value, from a relationship between each thickness of the masks and each depth ratio in the substrate.