Trenched Super Barrier Rectifier With Single Mask Etching
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Solution Overview
Problem
Conventional power rectifier processing requires multiple masks and steps, increasing complexity and inefficiency.
Innovation Solution
A method for forming a rectifier device with reduced mask count by combining the trench and guard ring masking stages into one, using lateral etching to expose corner portions of the substrate and preserve a portion of the second layer at the edge, allowing for a trenched super barrier or Schottky rectifier structure with reduced processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional processing uses separate 'ACTIVE' photo mask and 'TRENCH' photo mask to achieve desired rectifier structure, then manufacturing precision is maintained, but device complexity and processing steps increase
Solution Approach 1:
The patent combines the active region formation and trench formation into a single photo mask step. The photo mask is designed with patterns that define both the active diode regions and the trenches simultaneously, eliminating the need for separate masking steps and reducing overall device complexity while maintaining structural precision
Solution Approach 2:
The single photo mask serves multiple functions: it defines the active regions for diode formation, defines the trench locations and dimensions, and establishes the spatial relationship between active regions and trenches. This multi-functional approach reduces the number of processing steps while maintaining manufacturing precision
2Productivity
If multiple masks are used in conventional rectifier processing, then structural accuracy is achieved, but productivity decreases
Solution Approach 1:
By merging active region definition and trench definition into one photo mask step, the patent reduces the number of sequential processing steps required. This single-step approach increases manufacturing throughput and productivity while the carefully designed mask pattern ensures structural accuracy is maintained
Solution Approach 2:
The photo mask is designed in advance to incorporate all necessary patterning information for both active regions and trenches. This preliminary design allows all structural definitions to be established in one step, improving productivity without sacrificing the precision that would otherwise require multiple sequential masking steps
Data Source
AI summary
A method for forming a rectifier device is provided. The method forms a first layer on a substrate, a second layer is formed on the first layer and a photoresist layer is deposited on the second layer in which a plurality of trench patterns are formed. A plurality of trenches are formed in the first layer and the second layer by etching based on the trench patterns in the photoresist. The method then laterally etches the second layer to expose a corner portion of the first layer at mesas formed in between the two trenches. A portion of the second layer is preserved at an edge of the rectifier device.