Etching Method Correcting Mask Shape Deformation
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Solution Overview
Problem
During the etching of silicon-based materials using inert gas-based chemical species like Xe, Kr, or Rn, the mask is often severely damaged and deformed, leading to clogged openings, necessitating an improvement in the shape of the mask.
Innovation Solution
An etching method involving a substrate preparation step with a mask, followed by an etching step using plasma of a first gas containing Xe, Kr, or Rn to achieve an aspect ratio of 30 or more, and a correction step using a second gas to improve the mask shape, employing a capacitively coupled plasma processing apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma of inert gas-based chemical species (Xe, Kr, Rn) is used for etching silicon-based materials, then the aspect ratio of etched features can be improved, but the mask shape becomes severely damaged and deformed
Solution Approach 1:
The patent divides the etching process into two separate steps: a first etching step using inert gas-based chemical species to achieve high aspect ratio, and a second correction step to restore mask shape. This segmentation allows each step to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent performs the etching step with inert gas first to achieve the desired aspect ratio, then follows with a correction step to fix mask deformation. By performing the primary etching action first and then correcting the shape, the method ensures both high aspect ratio and mask integrity.
2Productivity
If plasma of inert gas-based chemical species is used for etching, then etching performance is improved, but mask openings become clogged due to deformation
Solution Approach 1:
The patent separates the etching process into two distinct steps: the first step focuses on achieving high etching performance with inert gas-based chemical species, while the second step specifically addresses mask opening integrity by correcting deformation and removing clogged portions.
Solution Approach 2:
The patent converts the harmful effect of mask deformation into a benefit by using the correction step to selectively remove deformed portions and restore mask openings. The deformation that would normally cause clogging is instead used as a guide for where correction is needed.
3Manufacturing precision
If heavy inert gas ions are used for etching, then anisotropic etching is enhanced, but mask damage increases
Solution Approach 1:
The patent divides the process into a first etching step that utilizes heavy inert gas ions for enhanced anisotropic etching, followed by a second correction step that removes the harmful mask damage caused by the heavy ions.
Solution Approach 2:
The patent performs the anisotropic etching with heavy inert gas ions first to achieve the desired directional etching performance, then applies the correction step to fix the mask damage that resulted from this preliminary action.
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
The method effectively corrects the shape of the mask by removing deformed portions, preventing clogging and maintaining the integrity of the mask, while allowing for independent control of ion impingement and chemical reactions, thereby improving the aspect ratio and shape of etched features.
Implementation Method 1
the first film is etched with plasma of a first gas containing Xe, Kr or Rn
Implementation Method 2
independent control of ion impingement and chemical reactions
Implementation Method 3
the shape of the mask is corrected with plasma of a second gas
Data Source
AI summary
An etching method and an etching apparatus improve the shape of a mask deformed by an etching process. The etching method for etching a film with plasma includes a step of providing a substrate, an etching step, and a correction step. In the step of providing a substrate, a substrate having a mask formed on a first film is provided. In the etching step, the first film is etched with plasma generated from a first gas containing Xe, Kr, or Rn so that an aspect ratio of a hole or a groove formed in the first film is 30 or more. In the correction step, the shape of the mask is corrected with plasma generated from a second gas.