Precursor Pulse Delivery with Bypass Flow and Back Suction
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Solution Overview
Problem
Existing gas-phase reactor systems face limitations in delivering precise pulses of precursors or reactants to reaction chambers, leading to restricted concentrations, slow pulsing speeds, inefficient purging, leakage, and unwanted backside deposition during manufacturing processes.
Innovation Solution
A novel apparatus and method utilizing a pressure flow controller, flow bypass assembly with variable conductance lines, and a back suction line to enhance the pulsing and purging efficiency, allowing for higher precursor concentrations, quicker flowrate changes, and reduced leakage, while minimizing backside deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mass flow controller and valve are used to pulse precursor gas, then the flowrate can be controlled to a predetermined value, but the precursor concentration delivered to the reaction chamber is limited and the pulsing speed is slow
Solution Approach 1:
The gas delivery system is segmented into multiple independent pathways: a first precursor delivery pathway with its own mass flow controller and valve, and a second precursor delivery pathway with separate flow control. This segmentation allows each pathway to operate independently, enabling faster pulsing by opening/closing only the necessary pathway while maintaining precise flow control through dedicated controllers for each path.
Solution Approach 2:
A carrier gas is introduced as an intermediary substance to transport the precursor gas from the source through the delivery pathways to the reaction chamber. The carrier gas enables rapid pulsing by allowing quick opening/closing of precursor delivery without requiring the precursor itself to be stored or handled directly, while mass flow controllers maintain precise concentration control of the precursor in the carrier gas stream.
2Quantity of substance
If a carrier or purge gas is used to assist with providing precursor during a pulse, then the precursor can be delivered to the reaction chamber, but the overall purge flowrate is limited and purge efficiency is reduced
Solution Approach 1:
The system segments the gas delivery into distinct precursor delivery pathways and purge pathways. The purge gas flows through dedicated purge lines that are separate from the precursor delivery pathways, allowing independent optimization of each function. This enables high purge flowrates through the purge pathways without compromising precursor delivery capability through the separate precursor pathways.
Solution Approach 2:
The system employs periodic pulsing of precursor gas followed by periodic purge cycles. During the pulse phase, precursor is delivered through the first or second precursor delivery pathway. During the purge phase, the purge gas flows through the purge pathways to clear residual precursor from the reaction chamber. This periodic alternation maintains high precursor delivery during pulses while achieving efficient purging during dedicated purge cycles.
3Measurement precision
If a valve is switched between open and closed positions to pulse precursor, then the precursor flowrate can be controlled, but system leakage occurs and unwanted backside deposition on substrate occurs
Solution Approach 1:
The gas delivery system is divided into multiple sealed pathways with individual valves. When precursor pulsing is not needed, the valves in inactive pathways can be closed to isolate that pathway, preventing leakage from open valves. The segmented design allows selective activation of only the necessary precursor delivery pathway, minimizing the number of open connections and reducing overall system leakage that could lead to backside deposition.
Solution Approach 2:
The carrier gas acts as an intermediary that carries the precursor through sealed delivery pathways to the reaction chamber. This intermediary approach allows precise control of precursor delivery through mass flow controllers while maintaining sealed pathways, reducing the risk of precursor leakage. The controlled delivery through the carrier gas medium prevents uncontrolled precursor release that could cause backside deposition on the substrate.
Data Source
AI summary
Apparatus, systems and methods for providing a pulse of a precursor are provided. The apparatus, systems and methods as described herein can be used to, for example, rapidly pulse a precursor to a reactor and provide relatively high flow of a purge gas during a purge of the reactor.