Atomic Layer Etching Parameter Ramping for HAR Profile Uniformity
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Solution Overview
Problem
Conventional atomic layer etching (ALE) processes face challenges in maintaining uniformity and precision when forming high aspect ratio (HAR) structures, particularly due to the difficulty in balancing ion and neutral fluxes, leading to non-uniform layer removal and undesirable etching profiles, especially as device geometries become more complex and smaller in scale.
Innovation Solution
The method involves dynamically adjusting process parameters such as the duration of the surface modification step and the bias level during the sputtering step in correlation with the ALE cycle count, using a pre-established model or empirical data from tests, to optimize the etching process for HAR structure formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ALE processes are used with fixed parameters, then the process is simple to operate, but the etching uniformity and precision deteriorate when forming high aspect ratio structures
Solution Approach 1:
The patent implements dynamic parameter adjustment where the surface modification duration and bias level are progressively changed as a function of ALE cycle count. This transforms the static fixed-parameter process into a dynamic adaptive process that responds to changing etching conditions, thereby improving etching uniformity for high aspect ratio structures while managing complexity through systematic control strategies.
Solution Approach 2:
The patent systematically varies process parameters including surface modification duration, bias level, and their progression rates as functions of ALE cycle count. These parameter changes are designed to adapt to the evolving etching conditions as material is removed, maintaining optimal etching performance throughout the formation of high aspect ratio structures.
2Manufacturing precision
If the surface modification duration is increased to improve etching completeness, then the etching precision improves, but the processing time increases
Solution Approach 1:
The patent applies periodic variation in surface modification duration through the progressive change function of ALE cycle count. Rather than using a constant extended duration, the process periodically adjusts the modification time to match the evolving needs of the etching front, achieving complete etching precision while minimizing total processing time through optimized cycle progression.
3Productivity
If the bias level is increased to enhance sputtering efficiency, then the etching rate improves, but the etching profile uniformity deteriorates
Solution Approach 1:
The patent implements dynamic bias level adjustment that progresses as a function of ALE cycle count. This dynamic approach allows the bias level to adapt to changing conditions during the etching process, maintaining optimal ion flux and energy distribution to achieve both high etching rates and uniform profiles in high aspect ratio structures.
Solution Approach 2:
The patent systematically varies the bias level parameter throughout the ALE process based on cycle count progression. This controlled parameter change enables the process to maintain optimal sputtering efficiency while preserving profile uniformity, balancing productivity and precision through adaptive parameter management.
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 enhances the precision and efficiency of ALE, ensuring high fidelity in forming HAR structures by adapting to the changing requirements of the etching process, thereby improving etching uniformity and selectivity.
Implementation Method 1
a plasma source to generate plasma
Implementation Method 2
a sputtering step to remove the modified layer from the substrate
Implementation Method 3
The bias unit is to provide a bias for the ions in the plasma
Data Source
AI summary
Disclosed herein is a method for high aspect ratio (HAR) structure formation in semiconductor manufacturing using atomic layer etching (ALE). The method involves dynamically adjusting process parameters such as surface modification step duration and sputtering step bias level in relation to the ALE cycle count. This adjustment can be guided by a pre-established model or empirical data from prior tests, enhancing precision and efficiency in HAR structure etching.