Laser-Heated Metallization Patterning for SiC Devices
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Solution Overview
Problem
Current methods for manufacturing patterned metal contacts on semiconductor devices, such as SiC devices, face challenges including irregular edge formation, contamination risks, and difficulty in achieving thick metal layers due to adhesion issues and etching selectivity problems, leading to high yield losses, especially in surface-sensitive devices like Schottky diodes.
Innovation Solution
A method involving the deposition of metallization layers on a substrate, followed by local heating using high-energy laser pulses to form etch-selective intermetallic compounds or alloys, allowing for selective etching without additional mask layers, thereby patterning thick metal layers without underetching or surface damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lift-off technique is used to manufacture patterned metal contacts, then metal layers can be deposited, but thick metal layers cannot be produced reliably and contamination of the semiconductor surface occurs
Solution Approach 1:
The patent changes the physical-chemical state of the metal layer by locally heating it to form intermetallic compounds with different etching properties. This parameter change enables selective removal of metal in specific areas while preserving metal in contact areas, solving the contradiction between achieving thick metal layers and maintaining pattern precision without contamination
Solution Approach 2:
The patent applies local heating to create spatially differentiated properties in the metal layer. The heated areas form intermetallic compounds with high etching selectivity, while non-heated areas retain original metal properties. This local quality differentiation enables precise patterning and reliable thick metal layer formation without contaminating the semiconductor surface
2Productivity
If plasma etching is used, then metal contacts can be etched, but the semiconductor surface is damaged and etch selectivity cannot be achieved
Solution Approach 1:
The patent creates local quality differentiation in the metal layer through selective heating, forming intermetallic compounds only in areas where metal removal is desired. This local transformation enables high etching selectivity that allows aggressive etching of the intermetallic compounds while completely protecting the semiconductor surface from damage
Solution Approach 2:
The intermetallic compound acts as an intermediary layer that facilitates selective removal of metal. This intermediary has fundamentally different etching properties compared to both the base metal and the semiconductor substrate, enabling high etching speed for the metal while providing complete protection to the semiconductor surface from plasma damage
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
Enables the reliable formation of patterned metallization with improved etching selectivity, reducing yield losses and contamination risks, and allowing for the creation of thick metal layers with precise control over structural details, enhancing the manufacturing of semiconductor devices like SiC diodes and JFETs.
Implementation Method 1
locally heating an area of the one or several metallization layers by means of a laser beam
Implementation Method 2
removing the metallization layer in the area or outside the area, depending on the etching selectivity in the area or outside the area, by etching with the etching medium
Data Source
AI summary
A method of manufacturing a device comprises depositing one or more metallization layers to a substrate, locally heating an area of the one or more metallization layers to obtain a substrate/metallization-layer compound or a metallization-layer compound, the compound comprising an etch-selectivity toward an etching medium which is different to that of the one or more metallization layers outside the area, and removing the one or more metallization layers in the area or outside the area, depending on the etching selectivity in the area or outside the area, by etching with the etching medium to form the device.