Low-Volatility Precursor Vapor Supply Without Carrier Gas
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Solution Overview
Problem
Existing precursor supply systems face challenges in delivering pure vapors of low volatility compounds, particularly solid precursors, due to insufficient vapor pressure and non-uniform deposition across fine patterns, which are exacerbated by the use of carrier gases that dilute the precursor and cause diffusion issues.
Innovation Solution
A method and system that evaporate precursors in a high-temperature vessel, transfer the vapor to a low-temperature buffer vessel without adding a carrier gas, and control the pressure to maintain a predetermined range, allowing for precise flow regulation using a flow control device within the buffer vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carrier gas is used to generate vapor of low volatility precursor, then sufficient vapor pressure and flow control are achieved, but deposition rate decreases and uniformity across fine patterns deteriorates
Solution Approach 1:
The patent extracts the carrier gas from the vapor generation process, using only pure precursor vapor without dilution. This is achieved by heating the precursor in a sealed vessel to generate sufficient vapor pressure directly, eliminating the need for carrier gas and thereby maintaining high deposition rates and uniformity across fine patterns.
Solution Approach 2:
The patent changes the temperature parameter of the precursor to generate sufficient vapor pressure without carrier gas. By controlling the precursor temperature in a sealed vessel, the system achieves the necessary vapor pressure for reliable flow control while maintaining pure precursor vapor for high-speed, uniform deposition.
2Ease of operation
If carrier gas is used to deliver precursor vapor, then flow control is improved, but precursor concentration decreases due to dilution
Solution Approach 1:
The patent removes the carrier gas component from the delivery system, delivering only pure precursor vapor. This extraction of the diluting element maintains maximum precursor concentration while flow control is achieved through precise temperature management of the precursor source.
3Stress or pressure
If temperature is increased to achieve sufficient vapor pressure for solid precursor, then vapor pressure increases, but heat conduction into solid bulk becomes insufficient
Solution Approach 1:
The patent introduces a liquid precursor intermediary that is heated to generate vapor, which then condenses on the solid precursor. This liquid-mediated heat transfer is more efficient than direct heating of solid, enabling sufficient vapor pressure generation while managing the low thermal conductivity of solid precursors.
4Manufacturing precision
If pure precursor vapor is used without carrier gas, then deposition uniformity improves, but vapor pressure becomes insufficient for flow control
Solution Approach 1:
The patent changes the temperature parameter of the precursor source to generate sufficient vapor pressure while maintaining pure precursor vapor without carrier gas. This temperature control enables both high deposition uniformity and adequate vapor pressure for flow management.
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 enables stable and uniform deposition of low volatility precursors across fine patterns by decoupling the vapor flow limitation from the maximum operating temperature of the flow control device, ensuring sufficient vapor pressure and uniform distribution without condensation.
Implementation Method 1
evaporating the precursor in a first vessel to form a precursor vapor
Implementation Method 2
heating a precursor storage vessel and a delivery line to increase the vapor pressure
Implementation Method 3
a pressure of the precursor vapor is reduced prior to the transfer to the second vessel to form a reduced pressure precursor vapor
Implementation Method 4
a flow rate of the reduced pressure precursor vapor to the point of use is at a pre-determined flow rate or flow rate range
Implementation Method 5
maintaining a partial pressure of the precursor in the second vessel at a pressure lower than the saturated vapor pressure of the precursor at the temperature of the second vessel
Data Source
AI summary
Supply system include a first vessel containing the precursor, a second vessel, a first gas conduit fluidically connecting the first vessel to the second vessel, wherein a pressure reduction device and a flow control device are fluidically mounted therein, a second gas conduit fluidically connecting the second vessel to a point of use, and a pressure gauge downstream the pressure reduction device for measuring a partial pressure of the precursor in the second vessel, wherein the partial pressure of the precursor in the second vessel is at a pressure lower than the saturated vapor pressure of the precursor at the temperature of the second vessel and higher than an inlet pressure requirement of the flow control device at the point of use. Methods for using the supply system are also disclosed.