ALD Layer Formation via Segmented Precursor Pulses
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Solution Overview
Problem
Atomic layer deposition (ALD) processes face challenges in growth rate per cycle, throughput, thickness uniformity, and contamination levels, particularly in batch processing, which affect semiconductor manufacturing efficiency and device reliability.
Innovation Solution
The method involves performing multiple deposition cycles with two precursor pulses and intervening purge pulses in a process chamber with pressure ranging from 0.1 to 10 Torr, optimizing the pressure ratio between pulses to enhance growth rate and uniformity, and using a substrate processing system with a controller to execute these cycles efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ALD deposition cycles are used, then layer formation is achieved, but growth rate per cycle is limited and throughput is reduced
Solution Approach 1:
The deposition cycle is segmented into multiple precursor pulses (first precursor pulse, second precursor pulse) with intervening purge pulses between them. This segmentation allows for more comprehensive surface coverage and complete reaction cycles, thereby increasing growth rate per cycle and improving throughput without compromising layer quality
Solution Approach 2:
The method employs periodic precursor pulses separated by purge pulses in a repeating deposition cycle. This periodic action ensures complete precursor delivery and reaction at each pulse, maximizing growth rate per cycle while maintaining controlled deposition conditions to improve throughput
2Productivity
If batch processing with multiple substrates is used, then productivity increases, but thickness uniformity deteriorates
Solution Approach 1:
The method applies different precursor pulses with specific pressure ratios to ensure uniform deposition across all substrates in the batch. By controlling the pressure ratio between precursor pulses and purge pulses locally at each pulse event, thickness uniformity is maintained while processing multiple substrates simultaneously
Solution Approach 2:
The method dynamically adjusts process parameters including pressure ratio between precursor pulses and purge pulses during each deposition cycle. This parameter change enables optimized deposition conditions that maintain thickness uniformity across multiple substrates while improving productivity through enhanced growth rate per cycle
3Device complexity
If single precursor pulse per cycle is used, then process simplicity is maintained, but contamination levels increase
Solution Approach 1:
The precursor delivery is segmented into multiple pulses with purge pulses in between. This segmentation allows complete evacuation of reaction byproducts and unreacted precursors between pulses, significantly reducing contamination levels in the deposited layer while adding only moderate process complexity
Solution Approach 2:
The multiple precursor pulses with intervening purge pulses ensure continuous and complete precursor delivery and reaction cycles. This continuous action prevents contamination by ensuring complete reaction at each pulse and thorough purging between pulses, maintaining high layer quality without excessive process complexity
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 increases the growth rate per cycle, reduces wafer within non-uniformity, improves thickness uniformity, and decreases contamination levels, leading to enhanced semiconductor device performance and manufacturing efficiency.
Implementation Method 1
The process chamber pressure during each deposition cycle may be in a range from about 0.1 Torr to about 10 Torr. During each deposition cycle, a ratio of the process chamber pressure during each precursor pulse of the at least two precursor pulses to the process chamber pressure during an intervening purge pulse may be equal or different from one another.
Data Source
AI summary
A method of forming a layer of a material on one or more substrates by ALD is disclosed. Embodiments of the presently described method comprise performing a plurality of deposition cycles comprising at least two precursors pulses with intervening purge pulses to form the layer of the material on the one or more substrates. During each deposition cycle, a ratio of the process chamber pressure during each precursor pulse of the at least two precursor pulses to the process chamber pressure during an intervening purge pulse is equal or different from one another.