Selective Silicon Oxide Removal via Plasma Denaturation and Reducing Gas Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for selectively removing silicon oxide regions in semiconductor manufacturing often result in the unintended removal of silicon regions due to oxidation, leading to reduced selectivity and process inefficiency.
Innovation Solution
A method involving multiple sequences of plasma processing using gases containing hydrogen, nitrogen, and fluorine to denature silicon oxide regions, followed by exposure to a reducing gas to prevent oxidation of silicon regions, and subsequent thermal decomposition or rare gas plasma to separate the denatured regions, while maintaining a clean processing environment to avoid fluorine-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma processing using gases containing hydrogen, nitrogen, and fluorine is used to denature silicon oxide regions, then the removal of silicon oxide is enhanced, but fluorine-induced damage to silicon regions occurs leading to unintended removal of silicon
Solution Approach 1:
A protective film is formed on the silicon regions before the plasma processing step. This protective film is applied in advance to prevent fluorine from reaching and damaging the silicon regions during the denaturation process, thereby maintaining high selectivity without causing harmful side effects
Solution Approach 2:
The protective film acts as an intermediary layer between the fluorine-containing plasma and the silicon regions. It allows the plasma to denature the silicon oxide while blocking the fluorine from directly contacting and damaging the silicon, thus resolving the contradiction between effective oxide removal and prevention of silicon damage
2Productivity
If multiple sequences of plasma processing are performed to enhance silicon oxide removal, then processing efficiency is improved, but the risk of silicon region damage accumulates
Solution Approach 1:
The protective film is formed before initiating multiple plasma processing sequences. This preliminary protective measure ensures that even when multiple sequences are performed to enhance productivity, the silicon regions remain protected from accumulated fluorine damage throughout the entire processing cycle
3Manufacturing precision
If thermal decomposition is used to remove denatured regions, then selective removal is achieved, but additional processing time is required
Solution Approach 1:
The method utilizes thermal decomposition, which relies on phase transition and chemical decomposition at elevated temperatures, to selectively remove the denatured silicon oxide regions. The protective film enables this thermal process to proceed without damaging the silicon regions, achieving high selective removal accuracy despite the additional time required for thermal processing
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 selectivity of silicon oxide removal while minimizing the removal of silicon regions, improving process efficiency and uniformity across varying pattern densities.
Implementation Method 1
forming a denatured region by generating plasma of a processing gas that contains hydrogen, nitrogen, and fluorine within a processing container
Implementation Method 2
forming a denatured region by generating plasma of a processing gas that contains hydrogen, nitrogen, and fluorine within a processing container that accommodates the workpiece so as to denature a portion of the first region
Implementation Method 3
removing the denatured region within the processing container
Implementation Method 4
exposing the workpiece to plasma of a reducing gas which is generated within the processing container
Implementation Method 5
exposing the workpiece to plasma of a reducing gas
Data Source
AI summary
Provided is a method of selectively removing a first region from a workpiece which includes the first region formed of silicon oxide and a second region formed of silicon. The method performs a plurality of sequences. Each sequence includes: forming a denatured region by generating plasma of a processing gas that contains hydrogen, nitrogen, and fluorine within a processing container that accommodates the workpiece so as to denature a portion of the first region, and removing the denatured region within the processing container. In addition, a sequence subsequent to a predetermined number of sequences after a first sequence among the plurality of sequences further includes exposing the workpiece to plasma of a reducing gas which is generated within the processing container, prior to the forming of the denatured region.