Oxide Semiconductor Transistor Residue Removal After Etching
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Solution Overview
Problem
The manufacturing process of semiconductor devices using oxide semiconductors often results in residue contamination from etching steps, leading to reduced reliability and electrical performance, such as decreased withstand voltage and increased leakage current.
Innovation Solution
A residue removal step using water, alkaline solutions, or plasma treatment is performed after forming the source and drain electrode layers to prevent contamination of the oxide semiconductor film and gate electrode layer surfaces, ensuring a surface density of residues like halogen, boron, phosphorus, aluminum, or carbon is kept below 1×10^13 atoms/cm^2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an etching step is performed to form metal layers (gate electrode layer or source and drain electrode layers), then the metal layers are successfully formed, but residue remains on the surface of the oxide semiconductor film and gate electrode layer, causing contamination
Solution Approach 1:
A residue removal step is performed after the etching step to eliminate contamination before subsequent processing steps. This preliminary cleaning action prevents residue from affecting later manufacturing steps and ensures high-quality interfaces between layers.
Solution Approach 2:
The etching residue, which is normally harmful contamination, is systematically removed through dedicated cleaning steps using water, alkaline solutions, or plasma treatment. By converting the harmful residue into a removable substance, the process transforms a manufacturing defect into a controlled intermediate state that can be eliminated.
2Reliability
If residue removal treatment is performed to eliminate contamination, then surface purity is improved, but additional manufacturing steps are required
Solution Approach 1:
Water, alkaline solutions, or plasma are used as intermediary substances to remove residue without damaging the underlying oxide semiconductor film or metal layers. These intermediaries selectively interact with the residue while leaving the device structures intact, enabling effective cleaning with minimal risk.
3Productivity
If residue remains on the oxide semiconductor film surface, then manufacturing process is simpler, but electrical characteristics deteriorate (decreased withstand voltage, increased leakage current)
Solution Approach 1:
The patent replaces purely mechanical/physical etching processes with a combination of chemical and physical cleaning methods. Water, alkaline solutions, or plasma treatment provide chemical and physical mechanisms to remove residue that mechanical processes alone cannot eliminate, thereby improving electrical characteristics without sacrificing manufacturing efficiency.
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 enhances the reliability and stability of semiconductor devices by maintaining stable electrical characteristics and improving manufacturing yield.
Implementation Method 1
plasma treatment using oxygen, dinitrogen monoxide, or a rare gas (typically argon) can be favorably used
Data Source
AI summary
When a semiconductor device including a transistor in which a gate electrode layer, a gate insulating film, and an oxide semiconductor film are stacked and a source and drain electrode layers are provided in contact with the oxide semiconductor film is manufactured, after the formation of the gate electrode layer or the source and drain electrode layers by an etching step, a step of removing a residue remaining by the etching step and existing on a surface of the gate electrode layer or a surface of the oxide semiconductor film and in the vicinity of the surface is performed. The surface density of the residue on the surface of the oxide semiconductor film or the gate electrode layer can be 1×1013 atoms/cm2 or lower.