Substrate Etching with Sidewall Protection Against Contact Hole Bowing
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Solution Overview
Problem
In semiconductor device manufacturing, shape abnormalities such as bowing in high aspect ratio contact holes pose challenges during the plasma etching process, particularly due to side-etching issues in organic films when using silicon-containing films as masks.
Innovation Solution
A method involving the formation of a protective film on the sidewalls of organic films by sputtering silicon-containing films, combined with specific etching and masking steps, to control the shape of patterns formed during etching, including the use of hydrogen plasma for forming protective films and oxygen-based plasmas for etching, and fluorine-based plasmas for preventing clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If plasma etching is used to form high aspect ratio contact holes, then etching depth and aspect ratio are improved, but shape abnormality such as bowing occurs in the organic film
Solution Approach 1:
A protective film is formed on the sidewall of the organic film before the main etching process. This preliminary protective layer prevents direct plasma exposure to the organic film during etching, thereby preventing bowing while allowing deep etching to proceed. The protective film is removed after etching is complete.
Solution Approach 2:
The protective film acts as an intermediary layer between the plasma and the organic film. It mediates the interaction by providing a barrier that prevents harmful plasma effects on the organic film while allowing the etching process to continue on the underlying layers.
2Manufacturing precision
If silicon-containing film is used as mask for etching organic film, then etching selectivity is improved, but side-etching and bowing occur in the organic film
Solution Approach 1:
The protective film is formed on the sidewall of the organic film before the silicon-containing mask etching process. This preliminary protection ensures that even though the silicon mask provides good etching selectivity, the organic film underneath remains protected from side-etching and bowing during the mask formation process.
3Device complexity
If conventional etching process is used without protective film, then process simplicity is maintained, but bowing and shape abnormality occur in high aspect ratio structures
Solution Approach 1:
The protective film formation step is added before the main etching process. Although this adds a step to the process, it is a relatively simple deposition step that can be integrated into existing process flows. The benefit of preventing bowing and shape abnormalities in high aspect ratio structures outweighs the minor increase in process complexity.
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 effectively reduces bowing and maintains pattern integrity by forming protective films at critical aspect ratios, ensuring precise control over pattern shapes and preventing clogging, thereby enhancing the manufacturing process for semiconductor devices.
Implementation Method 1
turning a first processing gas into plasma to etch the organic film and to form a protective film on a sidewall of the organic film by sputtering of the silicon-containing film
Implementation Method 2
plasma etching is used in forming a cylinder hole, a contact hole, or other structure in manufacturing a semiconductor device
Data Source
AI summary
An apparatus for processing a substrate includes a step of providing a substrate and a first step. In the step of providing a substrate, a substrate having a first film and a second film formed on the first film and having a pattern formed thereon is provided. In the first step, a protective film is formed on a side wall of the first film by a product generated by sputtering of the second film while a first processing gas is turned into plasma and the first film is etched simultaneously with the sputtering of the second film.