CMOS Transistor Manufacturing via Gate Electrode Masking
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Solution Overview
Problem
The CMOS transistor manufacturing process is complex and costly, with challenges in integrating multiple transistors effectively due to issues with leakage current and manufacturing efficiency.
Innovation Solution
A method involving the formation of gate insulating films, specific ion injection processes to create well regions and lightly doped drain regions in CMOS transistors, and the use of separation films to prevent leakage, with ion injection through gate electrode patterns to control depth and type of doping, and the formation of threshold voltage adjustment areas and Halo regions to improve transistor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional CMOS transistor manufacturing process is used, then transistor performance is maintained, but manufacturing complexity and cost increase
Solution Approach 1:
The manufacturing process is segmented into distinct stages: forming gate electrode patterns first, then using them as masks for sequential ion injection processes. This segmentation allows each step to be independently optimized and controlled, reducing overall process complexity while maintaining transistor performance
Solution Approach 2:
Gate electrode patterns are formed in advance before ion injection processes. These pre-formed patterns serve as masks that guide subsequent doping steps, eliminating the need for separate mask alignment processes and simplifying the overall manufacturing flow
2Manufacturing precision
If multiple masks are used for ion injection processes, then doping precision is improved, but manufacturing cost and process time increase
Solution Approach 1:
The gate electrode patterns serve multiple functions: they act as masks for ion injection, define transistor regions, and control doping depth through their thickness. This multi-functionality eliminates the need for separate sacrificial masks, reducing both process steps and time while maintaining doping precision
Solution Approach 2:
The gate electrode patterns automatically serve as their own masks during ion injection processes. The patterns' physical presence and thickness self-determine the doping profile without requiring external mask layers, streamlining the manufacturing process
3Ease of manufacture
If ion injection is performed through gate electrode patterns, then process steps are reduced, but control over doping depth becomes challenging
Solution Approach 1:
The gate electrode pattern thickness is precisely controlled as a key parameter to regulate ion injection depth. By adjusting the pattern thickness, the doping depth is automatically controlled without requiring separate depth-control mechanisms, maintaining precision while simplifying the process
Solution Approach 2:
Physical mask thickness replaces complex mechanical depth-control systems. The gate electrode pattern's dimensional parameter directly determines ion injection depth, substituting elaborate depth-control machinery with a simple geometric parameter
4Reliability
If separation films are added to prevent leakage current, then transistor reliability is improved, but device complexity increases
Solution Approach 1:
Separation films are merged with the gate insulating film structure, combining leakage prevention functionality with the existing insulating layer. This integration adds minimal structural complexity while effectively preventing leakage current between adjacent transistors
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 CMOS transistor manufacturing process, reduces manufacturing costs, and improves transistor characteristics by minimizing leakage current and enhancing integration, resulting in more efficient and cost-effective production with fewer masks required.
Implementation Method 1
performing a first ion injection process into the PMOS transistor area to form an n-type well region and a p-type lightly doped drain (LDD) region in the PMOS transistor area, wherein the performing of the first ion injection process includes performing ion injection through the exposed second gate electrode pattern in the PMOS transistor area
Data Source
AI summary
A CMOS transistor manufacturing method includes: forming a gate insulating film on a semiconductor substrate; forming a first gate electrode pattern on the gate insulating film in an NMOS transistor area; forming a second gate electrode pattern on the gate insulating film in a PMOS transistor area; forming a first photoresist pattern covering the NMOS transistor area to expose the second gate electrode pattern; performing a first ion injection process into the PMOS transistor area to form an n-type well region and a p-type LDD region; removing the first photoresist pattern; forming a second photoresist pattern covering the PMOS transistor area to expose the first gate electrode pattern; performing a second ion injection process into the NMOS transistor area to form a p-type well region and an n-type LDD region; removing the second photoresist pattern; and forming sidewall spacers at sidewalls of the first and second gate electrode patterns.