Oxide Semiconductor Transistor Impurity Removal
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Solution Overview
Problem
The manufacturing process of semiconductor devices using oxide semiconductors often results in shape defects and degradation of electric characteristics due to impurities from etching gases, leading to reliability issues and lower productivity.
Innovation Solution
A method involving the formation of a gate electrode layer, gate insulating film, and island-shaped oxide semiconductor film, followed by plasma treatment using an etching gas with a halogen element to create source and drain electrode layers, and subsequent impurity removal treatment to reduce halogen element concentration on the oxide semiconductor film surface, ensuring a reliable semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plasma treatment using etching gas containing halogen element is performed to form source and drain electrode layers, then the source and drain electrode layers are successfully formed, but halogen element impurities remain on the oxide semiconductor film surface causing reliability degradation
Solution Approach 1:
The patent applies the extraction principle by introducing a dedicated impurity removal step that specifically targets and removes halogen element impurities from the oxide semiconductor film surface after plasma treatment. This separates the electrode formation process from the impurity contamination effect, allowing the beneficial electrode formation while eliminating the harmful impurity deposition.
Solution Approach 2:
The patent converts the harmful halogen element impurities deposited during plasma treatment into a controllable parameter by introducing a subsequent removal step. The impurities that would normally degrade reliability are systematically eliminated through oxygen plasma treatment or chemical cleaning, transforming the harmful byproduct into a manageable process parameter.
2Adaptability or versatility
If multiple thin films are stacked to form the semiconductor device, then the device functionality is achieved, but shape defects and electric characteristic degradation occur due to impurities from manufacturing processes
Solution Approach 1:
The patent applies preliminary action by performing impurity removal treatment at a critical intermediate stage in the manufacturing process, specifically after source and drain electrode layer formation but before subsequent processing steps. This timing ensures that impurities are removed before they can affect later manufacturing steps, preventing shape defects and electric characteristic degradation in advance.
Solution Approach 2:
The patent introduces an intermediary cleaning step that acts as a mediator between the plasma treatment process and subsequent manufacturing steps. This intermediary treatment removes impurities that would otherwise transfer between different thin film layers, maintaining manufacturing precision across the multi-layer structure.
3Productivity
If conventional manufacturing processes are used to form oxide semiconductor transistors, then the basic device structure is created, but reliability is degraded due to impurity accumulation from various manufacturing steps
Solution Approach 1:
The patent maintains continuity of useful action by integrating the impurity removal treatment into the existing manufacturing flow without disrupting the overall production rhythm. The removal step is positioned at an optimal point in the process sequence, allowing continuous processing while systematically eliminating impurities that would otherwise accumulate and degrade reliability over multiple manufacturing steps.
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 yield of semiconductor devices by preventing impurity-induced defects, thereby improving the stability and performance of oxide semiconductor transistors.
Implementation Method 1
processing the conductive film by plasma treatment using an etching gas containing a halogen element
Implementation Method 2
oxygen plasma treatment or dinitrogen monoxide plasma treatment is preferably performed as the impurity removal treatment
Data Source
AI summary
A highly reliable semiconductor device and a method for manufacturing the semiconductor device are provided. The semiconductor device is manufactured with a high yield to achieve high productivity. In the manufacture of a semiconductor device including a transistor in which a gate electrode layer, a gate insulating film, and an oxide semiconductor film are sequentially stacked and a source electrode layer and a drain electrode layer are provided in contact with the oxide semiconductor film, the source electrode layer and the drain electrode layer are formed through an etching step and then a step for removing impurities which are generated by the etching step and exist on a surface of the oxide semiconductor film and in the vicinity thereof is performed.