Oxide Semiconductor Transistor Channel Length Control
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Solution Overview
Problem
The challenge is to miniaturize transistors for high-speed operation, low power consumption, and high integration while maintaining high yield and reliability in semiconductor devices, particularly in oxide semiconductor-based transistors, where existing techniques face issues with yield reduction and impurity contamination.
Innovation Solution
A semiconductor device structure and manufacturing method involving an oxide semiconductor film, gate insulating film, and gate electrode with a high gate electrode region height, using chemical mechanical polishing and electron beam exposure to define the channel length, and incorporating a hard mask film and insulating films to form source and drain electrodes, ensuring high purity and supersaturation of oxygen in the oxide semiconductor film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If transistor size is miniaturized to achieve high-speed operation and low power consumption, then on-state characteristics improve, but manufacturing yield decreases
Solution Approach 1:
The patent changes the material parameter from conventional semiconductor to oxide semiconductor, which enables miniaturization while maintaining stability. The oxide semiconductor film allows for smaller transistor dimensions without the same level of performance degradation, thus improving operation speed while maintaining manufacturing yield through material property optimization.
Solution Approach 2:
The patent employs an inert atmosphere approach by using oxide semiconductor materials that are inherently more stable and less susceptible to contamination during manufacturing. This creates a more forgiving manufacturing environment that maintains high yield even as transistor dimensions are reduced for high-speed operation.
2Productivity
If transistor size is miniaturized to achieve high integration, then device density improves, but impurity contamination increases
Solution Approach 1:
The patent utilizes the unique properties of oxide semiconductor materials that enable higher integration density while maintaining material purity. The oxide semiconductor film's characteristics allow for closer device spacing without the same level of impurity contamination issues that plague conventional semiconductors at small dimensions.
Solution Approach 2:
The patent employs a disposable-like approach with the oxide semiconductor film that can be precisely deposited and then selectively removed or processed. This allows for high integration density structures where materials are used efficiently and controllable contamination is managed through the inherent stability of the oxide semiconductor material.
3Speed
If channel length is shortened to improve transistor speed, then operation frequency increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the material parameter to oxide semiconductor, which provides more tolerant fabrication characteristics. This allows for shorter channel lengths to achieve higher operation frequencies while the material's properties maintain sufficient manufacturing precision without requiring extreme fabrication control.
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 enables the production of miniaturized transistors with improved on-state characteristics, high yield, and reduced power consumption, while maintaining high reliability and performance, by precisely controlling the channel length and reducing impurity concentrations.
Implementation Method 1
As the removing (or polishing) method, a chemical mechanical polishing (CMP) method can be preferably used
Implementation Method 2
a resist formed on the hard mask film is exposed to an electron beam
Data Source
AI summary
A first conductive film overlapping with an oxide semiconductor film is formed over a gate insulating film, a gate electrode is formed by selectively etching the first conductive film using a resist subjected to electron beam exposure, a first insulating film is formed over the gate insulating film and the gate electrode, removing a part of the first insulating film while the gate electrode is not exposed, an anti-reflective film is formed over the first insulating film, the anti-reflective film, the first insulating film and the gate insulating film are selectively etched using a resist subjected to electron beam exposure, and a source electrode in contact with one end of the oxide semiconductor film and one end of the first insulating film and a drain electrode in contact with the other end of the oxide semiconductor film and the other end of the first insulating film are formed.