Amorphous Carbon Thin Film Deposition via Low-Temperature ALD
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Solution Overview
Problem
Current methods for depositing thin films using polymer precursors in semiconductor manufacturing face challenges in achieving uniformity and excellent step coverage, particularly in high aspect ratio structures, despite their fast film-forming rates.
Innovation Solution
A method involving the alternating supply of ethylenediamine and 1,4-phenylene diisocyanate as polymer precursors in a thermal atomic layer deposition (ALD) process, with specific gas supply cycles and the use of plasma to enhance film quality and reduce thermal damage, while maintaining low substrate temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PECVD or CVD process is used to deposit amorphous carbon layer, then film-forming rate is fast and productivity is improved, but uniformity and step coverage of thin film deteriorate
Solution Approach 1:
The deposition process is segmented into multiple alternating half-cycles, where each half-cycle deposits a portion of the final film thickness. This segmentation allows each sub-deposition to achieve better uniformity and step coverage while maintaining overall productivity through parallel processing and optimized cycle times.
2Manufacturing precision
If polymer precursors are used in ALD process, then uniformity and step coverage are improved, but thermal damage to polymer film increases due to high substrate temperature
Solution Approach 1:
The substrate temperature is reduced to below 100°C, representing a significant parameter change from conventional ALD temperatures. This temperature reduction prevents thermal damage to the polymer film while maintaining the self-limiting deposition characteristics and excellent uniformity/step coverage benefits of ALD.
3Manufacturing precision
If conventional ALD process is used with polymer precursors, then excellent step coverage and uniformity are achieved, but film-forming rate is slow
Solution Approach 1:
The deposition process uses periodic alternating half-cycles with source gas A and source gas B supplied in sequence, separated by purge steps. This periodic action optimizes the deposition rate while maintaining the self-limiting nature of each half-cycle, achieving both high film-forming rate and excellent step coverage.
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 improves the uniformity and step coverage of thin films, achieving the desired thickness and optical characteristics for amorphous carbon layers, with increased purge efficiency and reduced damage to the polymer film.
Implementation Method 1
supplying a first source gas to a reactor during a first time, supplying a purge gas to the reactor during a second time, supplying a second source gas to the reactor during a third time
Implementation Method 2
Plasma may be simultaneously supplied in at least part of the first time and the third time
Data Source
AI summary
A method of depositing a thin film includes: supplying a first source gas to a reactor during a first time period; supplying a purge gas to the reactor during a second time period; supplying a second source gas to the reactor during a third time period; and supplying the purge gas to the reactor during a fourth time period, wherein the first source gas and the second source gas comprise polymer precursors, and wherein the first source gas and the second source gas are supplied at a temperature that is less than 100° C. or about 100° C. According to the method, uniformity and step coverage of a thin film can be improved by depositing an amorphous carbon layer using polymer precursors according to an Atomic layer deposition (ALD) method.