Sacrificial Oxide Films for Semiconductor Etching Defects
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Solution Overview
Problem
In semiconductor device manufacturing, foreign substances can adhere to the top surface of insulating films in the peripheral circuit region, leading to incomplete etching and defects, which affect the performance of the device.
Innovation Solution
A method involving the formation of sacrificial oxide films using both thermal oxidation and ISSG oxidation methods over the control gate electrode and remaining insulating film surfaces, ensuring complete removal of the insulating film and preventing foreign substances from acting as etching masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the insulating film is etched after control gate electrode formation, then the conductive film can be patterned, but foreign substances may adhere to the insulating film surface causing incomplete etching and device defects
Solution Approach 1:
The patent applies preliminary action by forming sacrificial oxide films on the insulating film surface before the etching process. This preventive measure ensures that even if foreign substances adhere to the surface, they cannot act as etching masks because the oxide layer is removed during the etching process, guaranteeing complete insulating film removal without defects
Solution Approach 2:
The sacrificial oxide film acts as an intermediary layer between the foreign substances and the insulating film. This intermediate oxide layer prevents foreign substances from directly interfering with the etching process, as the oxide is selectively removed while allowing the etching to proceed completely through the insulating film
2Reliability
If thermal oxidation is used to form sacrificial oxide films, then complete coverage is achieved, but the oxidation process time is extended
Solution Approach 1:
The patent applies parameter changes by utilizing ISSG oxidation, which changes the oxidation conditions and kinetics to achieve rapid oxide formation. This method maintains the reliability and complete coverage of sacrificial oxide films while dramatically reducing the oxidation process time compared to conventional thermal oxidation
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 prevents foreign substances from interfering with the etching process, allowing for the complete removal of the insulating film and improving the pattern integrity of the conductive film, thereby enhancing the performance and reliability of the semiconductor device.
Implementation Method 1
a step of oxidizing the side surface of the control gate electrode by a thermal oxidation method
Implementation Method 2
a step of oxidizing the surface of the cap insulating film and the surface of the part, which remains in the second region, of the insulating film by an ISSG oxidation method
Data Source
AI summary
The present invention improves the performance of a semiconductor device. In a manufacturing method of a semiconductor device, sacrificial oxide films are formed over the side surface of a control gate electrode formed in a memory cell region, the surface of a cap insulating film formed in the memory cell region, and the surface of the part, which remains in a peripheral circuit region, of an insulating film. The step of forming the sacrificial oxide films includes the steps of: oxidizing the side surface of the control gate electrode by a thermal oxidation method; and oxidizing the surface of the cap insulating film and the surface of the part, which remains in the peripheral circuit region, of the insulating film by an ISSG oxidation method.