Plasma Etching Mask Protection via Temperature-Controlled Polymer Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor fabrication, plasma etching processes face challenges in accurately transferring photoresist mask patterns onto substrates due to erosion and distortion of the mask material, especially in advanced devices with high aspect ratio features, where excessive or inadequate etching resistant coatings can hinder the etching process and lead to pattern distortions and feature deformation.
Innovation Solution
A method is developed to control the plasma process by determining a time-dependent substrate temperature and temperature differential between the substrate and the upper plasma boundary, using temperature control devices to manage the sticking coefficient and flux of etching resistant materials, ensuring precise deposition and protection of the mask material during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching is used to transfer photoresist mask patterns, then etching capability is improved, but mask material erosion and pattern distortion occur
Solution Approach 1:
A polymer coating is introduced as an intermediary protective layer between the plasma environment and the photoresist mask material. This coating acts as a sacrificial barrier that absorbs plasma damage, preventing direct erosion of the mask pattern while allowing the etching process to proceed effectively on the underlying substrate.
Solution Approach 2:
The patent controls plasma process parameters including gas composition, power levels, and pressure to optimize the balance between etching efficiency and mask protection. By adjusting these parameters, the plasma chemistry is tuned to enhance anisotropic etching while minimizing lateral mask erosion and pattern distortion.
2Manufacturing precision
If etching resistant coating is applied to protect mask material, then mask erosion is reduced, but etching process is hindered when coating is excessive
Solution Approach 1:
The patent applies a controlled amount of polymer coating that is sufficient to protect the mask material from plasma erosion but not so excessive as to block etching constituents from reaching the substrate. This partial action approach optimizes the protective function while maintaining etching efficiency, particularly for high aspect ratio features where complete coverage would be detrimental.
3Manufacturing precision
If photoresist mask is used for pattern transfer, then pattern definition is achieved, but mask opening size reduction occurs due to byproduct deposition
Solution Approach 1:
The patent converts the harmful deposition of etching byproducts into a beneficial protective polymer coating on the mask sidewalls. This coating, which would normally be considered unwanted contamination, actually serves to protect the mask material from lateral erosion and maintains opening dimensions throughout the etching process, particularly for deep high aspect ratio features.
4Adaptability or versatility
If high aspect ratio features are etched, then device complexity is increased, but mask erosion and pattern distortion become more severe
Solution Approach 1:
The patent applies preliminary protective polymer coating to the mask material before and during the etching process. This pre-established protective layer is particularly critical for high aspect ratio features where the mask is exposed to plasma for extended periods, preventing cumulative erosion and maintaining pattern accuracy throughout the deep etching process.
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 allows for accurate transfer of mask patterns, minimizes mask material erosion, and maintains the integrity of high aspect ratio features by optimizing the distribution and adhesion of etching resistant coatings, thereby enhancing etching selectivity and anisotropy while preventing premature shutdown or widening of etched features.
Implementation Method 1
The time-dependent substrate temperature at any given time is determined based on control of a sticking coefficient of a plasma constituent at the given time
Implementation Method 2
The time-dependent temperature differential at any given time is determined based on control of a flux of the plasma constituent directed toward the substrate at the given time
Implementation Method 3
A method is developed to control the plasma process by determining a time-dependent substrate temperature and temperature differential between the substrate and the upper plasma boundary, using temperature control devices to manage the sticking coefficient and flux of etching resistant materials
Data Source
AI summary
A time-dependent substrate temperature to be applied during a plasma process is determined. The time-dependent substrate temperature at any given time is determined based on control of a sticking coefficient of a plasma constituent at the given time. A time-dependent temperature differential between an upper plasma boundary and a substrate to be applied during the plasma process is also determined. The time-dependent temperature differential at any given time is determined based on control of a flux of the plasma constituent directed toward the substrate at the given time. The time-dependent substrate temperature and time-dependent temperature differential are stored in a digital format suitable for use by a temperature control device defined and connected to direct temperature control of the upper plasma boundary and the substrate. A system is also provided for implementing upper plasma boundary and substrate temperature control during the plasma process.