Semiconductor Doping Layout Using Nested Hard Masks for Alignment
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Solution Overview
Problem
Existing semiconductor manufacturing methods face challenges in accurately aligning doping regions, leading to misalignment errors and suboptimal performance of semiconductor structures, particularly in high-pressure, high-temperature, and high-frequency applications.
Innovation Solution
The use of patterned hard masks as shielding layers for self-aligned doping processes, allowing precise formation of multiple doping regions through sequential implantation steps, ensuring accurate positioning and reducing misalignment errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doping methods are used, then the manufacturing process is simple, but the alignment precision of doping regions deteriorates
Solution Approach 1:
The hard mask is formed in advance before the doping process, serving as a pre-established alignment reference. The first hard mask is created through photolithography and etching processes prior to ion implantation, ensuring that subsequent doping regions are precisely positioned relative to the gate structure. This preliminary positioning structure enables accurate alignment without requiring complex real-time adjustment mechanisms during doping.
Solution Approach 2:
The doping process is divided into multiple sequential steps with distinct hard masks for different doping regions. First doping regions, second doping regions, and third doping regions are formed in separate implantation steps, each protected by its own hard mask structure. This segmentation allows independent optimization of alignment for each doping region while maintaining overall process control.
2Manufacturing precision
If multiple doping regions are formed sequentially, then the alignment accuracy improves, but the manufacturing time increases
Solution Approach 1:
Multiple hard masks are combined in a nested configuration where the second hard mask surrounds the first hard mask, and the third hard mask surrounds the second hard mask. This merged structure allows multiple doping regions to be defined within a single mask assembly, enabling simultaneous alignment reference for all doping steps and reducing the number of separate mask fabrication cycles required.
Solution Approach 2:
The hard masks are arranged in a nested configuration where inner hard masks are surrounded by outer hard masks. The first hard mask is positioned within the second hard mask, which is in turn positioned within the third hard mask. This nested arrangement allows multiple doping regions to be precisely defined with shared alignment references, reducing the cumulative time required for separate mask alignments while maintaining high precision.
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 enables the precise formation of doping regions in semiconductor structures, enhancing performance in high-voltage and high-frequency applications by improving alignment accuracy and reducing manufacturing errors.
Implementation Method 1
performing a first implantation process using the first patterned hard mask to form a first doped region in the epitaxial layer
Data Source
AI summary
Various methods for manufacturing semiconductor structures are provided. A first patterned hard mask is formed on a protective layer, which includes an opening exposing a portion of the protective layer and surrounded by side surfaces of the first patterned hard mask. A second patterned hard mask is formed on the side surfaces of the first patterned hard mask. A first doped region is formed in a portion of an epitaxial layer below the opening by implantation through the second patterned hard mask. The second patterned hard mask is removed. A second doped region surrounding the first doped region is then formed in the portion of the epitaxial layer by implantation through the first patterned hard mask. The first patterned hard mask is trimmed to form a third patterned hard mask, through which a third doped region is formed along a sidewall of the second doped region by implantation.