Mask Protective Film for Selective Etching
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Solution Overview
Problem
In substrate processing, the selective etching of interlayer insulating films using laminated masks faces challenges such as mask loss and insufficient selectivity due to inadequate protection of the mask, leading to etch stop phenomena, especially in forming multi-layer wiring patterns.
Innovation Solution
A substrate processing method involving the formation of a protective film on the side walls of masks using plasma generated from specific gases, such as C3H6 and N2, followed by etching with CF4 and H2 gases, to prevent mask loss and ensure selective etching of the interlayer insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laminated mask is used for selective etching of interlayer insulating films, then etching selectivity is improved, but mask loss occurs and etch stop phenomena appear due to inadequate mask protection
Solution Approach 1:
A protective film is formed on the side wall of the second mask before the etching process begins. This preliminary protective layer prevents mask loss and etch stop phenomena during selective etching of the interlayer insulating film, while maintaining the etching selectivity provided by the laminated mask structure
Solution Approach 2:
The protective film acts as an intermediary layer between the second mask and the etching environment. This intermediate protective film prevents direct contact between the mask and corrosive etchants, thereby preventing mask loss while allowing the laminated mask to maintain its selective etching function
2Productivity
If plasma processing is used for etching, then processing efficiency is improved, but mask loss occurs due to insufficient mask protection
Solution Approach 1:
The protective film is formed on the mask side wall before plasma etching begins. This preliminary protection allows high-efficiency plasma processing to proceed without mask loss, as the protective film absorbs the corrosive effects of the plasma on the mask material
Solution Approach 2:
The protective film serves as an intermediary barrier during plasma processing. It protects the mask from direct plasma exposure while allowing the plasma to effectively etch the interlayer insulating film, thereby maintaining both processing efficiency and preventing mask loss
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 method effectively suppresses mask loss and achieves the desired shape of the etching target film by forming a protective film on the side walls of the masks, maintaining etching selectivity and preventing etch stop, thus improving the processing efficiency and pattern formation in multi-layer wiring.
Implementation Method 1
a protective film is formed on a side wall of the second mask by plasma generated from a first gas
Implementation Method 2
forming a protective film on the side walls of masks using plasma generated from specific gases, such as C3H6 and N2
Implementation Method 3
the etching target film is etched with plasma generated from a second gas
Implementation Method 4
In the etching step, the etching target film is etched with plasma generated from a second gas
Data Source
AI summary
A substrate processing method includes a providing step, a forming step, and an etching step. In the providing step, a substrate including an etching target film, a first mask formed on the etching target film, and a second mask formed to cover at least a part of the first mask is provided. In the forming step, a protective film is formed on a side wall of the second mask by plasma generated from a first gas. In the etching step, the etching target film is etched with plasma generated from a second gas.