Semiconductor Gate Structure Formation via Preliminary Masking
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Solution Overview
Problem
The existing methods for manufacturing semiconductor devices, such as image sensors, often result in inadequate junction profiles for photodiodes due to suboptimal gate structure profiles, leading to deteriorated electrical characteristics and potential system malfunctions.
Innovation Solution
A method involving the sequential formation of insulating and conductive films on a semiconductor substrate, with precise masking and etching techniques to create impurity diffused regions and gate structures, ensuring accurate alignment and improved pattern fidelity for both photodiodes and gate structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gate structure is formed with conventional methods, then the manufacturing process is simple, but the junction profile of the photodiode becomes inadequate
Solution Approach 1:
The manufacturing process is divided into multiple sequential stages: first forming a preliminary gate structure, then performing impurity ion implantation, and finally forming the definitive gate structure. This segmentation allows each stage to be optimized independently, achieving precise junction profiles without compromising overall process manageability.
Solution Approach 2:
A preliminary gate structure is formed before the actual photodiode fabrication. This preliminary structure serves as a temporary guide for impurity ion implantation, ensuring accurate junction profiles. The preliminary structure is later removed and replaced with the final gate structure, sacrificing temporary complexity for long-term precision.
2Manufacturing precision
If the gate structure profile is optimized for photodiode formation, then the photodiode junction profile improves, but the gate structure itself may be influenced adversely by process environment
Solution Approach 1:
The preliminary gate structure is formed with optimized dimensions and materials specifically tailored for guiding impurity ion implantation. This temporary structure ensures precise junction profiles while being designed to minimize adverse interactions with the process environment during subsequent fabrication steps.
Solution Approach 2:
The methodology employs different material compositions and dimensional parameters for the preliminary gate structure compared to the final gate structure. The preliminary structure uses parameters optimized for implantation guidance, while the final structure uses parameters optimized for electrical performance, resolving the conflict between junction profile precision and electrical reliability.
3Productivity
If conventional single-step gate formation is used, then the process is fast, but the photodiode and gate structure electrical characteristics deteriorate
Solution Approach 1:
The gate formation process is segmented into distinct phases: preliminary gate formation, impurity ion implantation, and final gate structure formation. While this increases the number of steps compared to conventional single-step formation, each phase is optimized to be efficient, and the overall process achieves superior electrical characteristics that prevent system malfunctions, thereby maintaining acceptable productivity.
Solution Approach 2:
The preliminary gate structure is formed quickly using conventional methods, then serves as a template for precise impurity ion implantation. This approach allows the time-consuming precision work to be focused only on the critical implantation step, while the gate formation itself remains relatively fast, balancing productivity and reliability.
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 approach ensures the formation of semiconductor devices with enhanced electrical characteristics and improved reliability, preventing malfunctions in information processing systems by achieving desired junction profiles and feature sizes.
Implementation Method 1
Impurity ions are implanted to penetrate the first insulating film and the first conductive film into the semiconductor substrate using the first mask pattern as a mask, thereby forming an impurity diffused region in the semiconductor substrate
Implementation Method 2
The exposed part of the first conductive film, and a portion of the first structure are etched using the second mask pattern as an etch mask to form a gate structure in the first region
Data Source
AI summary
Provided is a method of forming a semiconductor device. The method includes forming an insulating film on a semiconductor substrate, a conductive film on the insulating film, and a first structure and a second structure on the conductive film. The semiconductor substrate has first and second regions. The first and second structures are formed on the first and second regions, respectively. An impurity diffused region is formed in the semiconductor substrate using the first structure as a mask. The impurity diffused region overlaps the first structure. A portion of the first structure, and the conductive film are etched to respectively form a gate structure and a capacitor structure on the first and second regions.