Semiconductor Fabrication Using Maskless Ion Implantation
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Solution Overview
Problem
The fabrication of semiconductor integrated circuit devices is complex due to the need for multiple masks, which increases costs and complexity, and existing methods do not effectively enhance the current driving capability without using masks.
Innovation Solution
A method involving the formation of buried impurity layers and an epitaxial layer on a substrate without using masks, where impurities of different conductivity types are implanted using blank implantation to improve the current driving capability of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple masks are used in the fabrication process, then the current driving capability can be improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the mask layer from the fabrication process. By using ion implantation techniques directly on the substrate without requiring mask films, the method simplifies the fabrication process while maintaining the ability to create complex doping patterns. This resolves the contradiction by removing the source of complexity (masks) while preserving the functional outcome (current driving capability through proper doping profiles).
Solution Approach 2:
The patent replaces the mechanical/photochemical mask system with a direct ion implantation system. Instead of using physical mask layers that require deposition, patterning, and removal steps, the invention uses controlled ion implantation to directly create the desired doping profiles. This substitution eliminates the complexity associated with mask handling while achieving the same electrical characteristics.
2Power
If multiple masks are used in the fabrication process, then the current driving capability can be improved, but the manufacturing cost increases
Solution Approach 1:
The patent removes the mask-related cost components from the fabrication process. By eliminating mask material purchases, mask alignment equipment requirements, and multiple processing steps associated with mask-based patterning, the invention significantly reduces manufacturing costs while maintaining the ability to achieve high current driving capability through optimized doping profiles.
Solution Approach 2:
The patent replaces expensive, multi-step mask-based processes with a more economical direct ion implantation approach. The method uses simpler, more cost-effective equipment and materials that can be applied directly to the substrate without requiring costly mask layers and associated processing infrastructure.
3Power
If buried impurity layers are formed with different concentrations, then the current driving capability is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent segments the doping process into multiple discrete ion implantation steps, each creating a specific buried impurity layer with a defined concentration. By dividing the overall doping profile into separate controllable steps (first buried impurity layer, second buried impurity layer, third buried impurity layer), the method achieves precise concentration control while enhancing current driving capability. Each segment can be independently optimized without affecting the others.
Solution Approach 2:
The patent applies different impurity concentrations at different depths and locations within the substrate to create optimized local electrical properties. The first buried impurity layer has a first concentration, the second has a second concentration, and the third has a third concentration, with each locally optimized for its specific function. This local quality approach enables high current driving capability while maintaining manufacturing precision through controlled spatial variation.
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 method simplifies the fabrication process, reduces costs, and enhances the current driving capability of semiconductor integrated circuit devices by forming buried impurity layers and an epitaxial layer, achieving stable device characteristics and higher breakdown voltages without the need for masks.
Implementation Method 1
forming a first buried impurity layer, which contains impurities of a first conductivity type and of a first concentration, in a surface of the exposed portion of the substrate by using the mask film; forming a second buried impurity layer, which contains impurities of a second conductivity type and of a second concentration, using blank implantation
Implementation Method 2
forming an epitaxial layer on the substrate having the first and second buried impurity layers
Data Source
AI summary
Provided are a method of fabricating a semiconductor integrated circuit device and a semiconductor integrated circuit device fabricated using the method. The method includes: forming a mask film, which exposes a portion of a substrate, on the substrate; forming a first buried impurity layer, which contains impurities of a first conductivity type and of a first concentration, in a surface of the exposed portion of the substrate by using the mask film; removing the mask film; forming a second buried impurity layer, which contains impurities of a second conductivity type and of a second concentration, using blank implantation; and forming an epitaxial layer on the substrate having the first and second buried impurity layers, wherein the first concentration is higher than the second concentration.