Isotropic Etching via Modified Film and Protective Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching techniques face limitations due to differences in vertical and horizontal etching rates, leading to anisotropic etching, which restricts semiconductor manufacturing processes and aims to achieve isotropic etching by reducing plasma directivity influence.
Innovation Solution
A substrate processing method involving the formation of a modified film by supplying a modifying gas and subsequent removal using a plasma-activated removal gas, while simultaneously providing a protective-film-forming gas to reduce etching rate differences and promote isotropic etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If neutral metastable gas (plasma) is used to etch the layer on substrate, then the etching proceeds in vertical direction with high directivity, but the removal of layer on side wall surface below mask is reduced, resulting in anisotropic etching
Solution Approach 1:
The etching process is divided into multiple sequential steps: first adsorbing halogen-containing gas to modify the film, then etching with neutral metastable gas, and finally removing the mask. This segmentation allows each step to be optimized independently, achieving both vertical precision and side wall removal
Solution Approach 2:
The halogen-containing gas is adsorbed onto the film surface before the actual etching process begins. This preliminary modification of the film makes it more susceptible to subsequent etching, enabling better control over both vertical and horizontal etching rates
2Speed
If plasma directivity is utilized for vertical etching, then vertical etching rate is improved, but horizontal etching rate decreases, creating difference between vertical and horizontal etching rates
Solution Approach 1:
The patent changes multiple process parameters including gas composition (halogen-containing gas mixed with inert gas), gas flow rates, pressure, and temperature to control the balance between vertical and horizontal etching rates, achieving isotropic etching when needed
3Manufacturing precision
If modifying gas is supplied to form modified film, then film modification is achieved, but additional process step is added, increasing process complexity
Solution Approach 1:
The film modification step using halogen-containing gas is merged with the etching process rather than being a completely separate step. The same gas supply system and process chamber are used, reducing overall process complexity while maintaining film modification quality
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 reduces plasma directivity influence, enabling isotropic etching by controlling the etching process to achieve uniform film removal, thus improving semiconductor device manufacturing efficiency.
Implementation Method 1
forming a modified film by supplying a modifying gas to modify a deposited film on a substrate
Implementation Method 2
supplying a removal gas activated by plasma
Implementation Method 3
the layer on the substrate is etched by using a neutral metastable gas (for example, plasma of Ar or the like)
Implementation Method 4
supplying a protective-film-forming gas at least at the same time
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
There is provided a technique that includes forming a modified film by supplying a modifying gas to modify an unmasked deposited film on a substrate; and removing the modified film, including supplying a removal gas activated by plasma and supplying a protective-film-forming gas at least at the same time.