ALD Precursor Dosing with Dynamic Valve Timing
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Solution Overview
Problem
Current precursor delivery systems in semiconductor processing tools lead to precursor waste and inefficiencies, such as long dose times, reduced throughput, and wafer defects due to improper timing of valve operations and continuous precursor flow.
Innovation Solution
A method and apparatus for controlling precursor flow by decoupling ampoule and process chamber valve operations from process steps, optimizing line charge and adsorption times, and dynamically adjusting valve opening and closing to minimize precursor usage and waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precursor flow is continuously maintained from ampoule to process chamber, then precursor delivery is ensured, but precursor waste increases and dose time increases
Solution Approach 1:
The gas line is pre-charged with precursor vapor before the actual dose step begins. The ampoule valve is opened in advance to allow precursor to fill the gas line and reach the process chamber, so that when the dose step starts, the precursor is already positioned and ready for immediate use, eliminating the need for continuous flow during the dose step.
Solution Approach 2:
The precursor flow is converted from continuous to periodic/pulsed operation. The ampoule valve is opened only during specific time intervals (pre-charge phase and dose phase) rather than continuously, allowing precursor to be delivered in controlled bursts rather than constant flow, thereby reducing waste while ensuring adequate supply.
2Speed
If ampoule valve is opened early to charge gas line, then precursor delivery timing is improved, but precursor usage increases
Solution Approach 1:
The gas line is pre-charged with a controlled amount of precursor vapor before the dose step. By opening the ampoule valve in advance for a calculated duration, the system ensures that sufficient precursor is available in the gas line for the upcoming dose, optimizing delivery timing without excessive usage.
Solution Approach 2:
The system uses partial action by charging the gas line with just enough precursor for the anticipated dose requirements, rather than over-charging. The valve opening duration and flow rate are carefully controlled to provide sufficient precursor for the dose step without significant excess that would be wasted.
3Ease of operation
If valve operations are synchronized with process steps, then process control is simplified, but precursor waste and dose time increase
Solution Approach 1:
The precursor delivery process is segmented into distinct phases: pre-charge phase (valve open early to fill gas line), dose phase (valve opens at start of dose step), and post-dose phase (valve closes after dose). This segmentation allows each phase to be optimized independently, improving overall productivity while maintaining control.
Solution Approach 2:
The valve operation timing is made dynamic rather than static. The ampoule valve opens at a calculated time before the dose step based on gas line volume, flow rate, and required precursor amount. This dynamic timing optimization allows the system to adapt to different conditions and minimize both waste and dose time.
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
Enhances precursor utilization efficiency, reduces waste, and improves throughput by ensuring precise precursor delivery to the process chamber, minimizing defects and optimizing process times.
Implementation Method 1
one or more vaporized precursors are flowed from an ampoule onto a semiconductor wafer
Implementation Method 2
flowing gas through a gas line
Implementation Method 3
adsorption times, and/or line charge times
Data Source
AI summary
Methods and apparatuses for controlling precursor flow in a semiconductor processing tool are disclosed. A method may include flowing gas through a gas line, opening an ampoule valve(s), before a dose step, to start a flow of precursor from the ampoule to a process chamber through the gas line, closing the ampoule valve(s) to stop the precursor from flowing out of the ampoule, opening a process chamber valve, at the beginning of the dose step, to allow the flow of precursor to enter the process chamber, and closing the process chamber valve, at the end of the dose step, to stop the flow of precursor from entering the process chamber. A controller may include at least one memory and at least one processor and the at least one memory may store instructions for controlling the at least one processor to control precursor flow in a semiconductor processing tool.