Tandem Plasma Source for ALD Cycle Time Reduction
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Solution Overview
Problem
Atomic layer deposition (ALD) processes face long cycle times and contamination issues due to plasma cycling, which affects the adsorption and activation of precursors on substrate surfaces.
Innovation Solution
A method involving dual plasma power levels is used, where a first power level enhances precursor adsorption without decomposition, followed by a second power level for decomposition, utilizing inductively coupled plasma (ICP) and capacitively coupled plasma (CCP) sources to improve adsorption efficiency and reduce contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma is cycled on and off during ALD processing, then precursor activation is achieved, but cycle time increases and contamination occurs
Solution Approach 1:
The plasma source is divided into two independent plasma sources that can operate simultaneously or independently. The first plasma source performs precursor activation while the second plasma source performs film deposition, allowing these two functions to be segmented and executed in parallel, thereby reducing the overall cycle time while maintaining reliable precursor activation
Solution Approach 2:
The first plasma source is used to activate precursors in advance before the actual film deposition step. By performing preliminary activation of the precursor molecules, the system ensures that when the second plasma source begins deposition, the precursors are already in the appropriate state for efficient film formation, reducing the total processing time
2Reliability
If plasma power is increased to activate precursor, then activation efficiency improves, but precursor decomposition occurs
Solution Approach 1:
The plasma activation and deposition functions are segmented into two separate plasma sources. The first plasma source operates at optimized power levels for precursor activation without causing excessive decomposition, while the second plasma source handles the deposition process. This segmentation allows each source to be independently optimized for its specific function
Solution Approach 2:
The first plasma source acts as an intermediary that prepares the precursor molecules for deposition by activating them to a suitable energy state. This intermediary activation step ensures that precursors are activated efficiently without the harsh conditions that would cause excessive decomposition, as the second plasma source then completes the process under controlled conditions
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 reduces cycle times, increases throughput, and minimizes contamination by optimizing precursor interaction with the substrate, enhancing the kinetic improvement for adsorption and supporting gap fill applications while avoiding parasitic chemical vapor deposition.
Implementation Method 1
the first power level is sufficient to enhance adsorption of the precursor on a surface of the substrate
Implementation Method 2
activating the precursor that is adsorbed using plasma having a second power level, wherein the second power level is greater than the first power level and is sufficient to decompose the precursor that is adsorbed
Implementation Method 3
The first power level is supplied by an inductively coupled plasma source
Implementation Method 4
The first power level is supplied by a capacitively coupled plasma source
Implementation Method 5
flowing reactant gases into a process chamber
Data Source
AI summary
A substrate processing system includes a first power source configured to supply plasma having a first power level, a second power source configured to supply plasma having a second power level greater than the first power level, and a controller configured to dose a process chamber with precursor. The first power level is sufficient to enhance adsorption of the precursor on a surface of a substrate and is insufficient to decompose the precursor that is adsorbed. The controller is further configured to remove a portion of the precursor that does not adsorb onto the substrate from the process chamber while the plasma having the first power level is being supplied and activate the precursor that is adsorbed using plasma having the second power level while the plasma having the first power level is still being supplied. The second power level is sufficient to decompose the precursor that is adsorbed.