Raw Material Container Pressure Control for CVD Vaporization
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Solution Overview
Problem
Conventional bubbling methods for film formation in semiconductor device manufacturing face challenges in stabilizing vaporization efficiency, leading to reduced throughput and raw material loss due to the time required for vaporization efficiency to stabilize and the complexity of process condition determination.
Innovation Solution
A film forming method and apparatus that involves increasing pressure inside the raw material container, stabilizing vaporization efficiency by discarding raw material gas via an exhaust bypass path, and monitoring the difference between measured flow rates of raw material and carrier gases to determine the optimal transition to film formation, allowing for more efficient and uniform film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional bubbling method is used to supply raw material gas, then particle generation is reduced and clogging is minimized, but the vaporization efficiency is difficult to stabilize and the time to reach stable operation is extended
Solution Approach 1:
The system performs preliminary actions by pre-vaporizing raw material in the raw material container before actual film formation begins. The carrier gas flows through the raw material container to establish stable vaporization conditions in advance, so that when film formation starts, the vaporization efficiency is already stabilized, eliminating the need to discard raw material gas during stabilization period
Solution Approach 2:
The raw material container serves as an intermediary between the raw material reservoir and the processing container. It pre-processes the raw material by vaporizing it with carrier gas under controlled conditions, creating a stable raw material gas source that can be supplied to the processing container without requiring stabilization during actual operation
2Productivity
If the carrier gas flow rate is increased to accelerate vaporization, then the time to stabilize is reduced, but the raw material loss increases due to discarding excess gas
Solution Approach 1:
The system uses mass flow meters to monitor the carrier gas flow rate and the raw material gas supply amount in real-time. This feedback mechanism allows precise control of the carrier gas flow to match the actual vaporization rate, preventing excessive flow that would cause raw material loss while ensuring sufficient flow to maintain stable vaporization and high productivity
Solution Approach 2:
The system dynamically adjusts the carrier gas flow rate parameter based on the vaporization state and process requirements. By optimizing this parameter, the system achieves stable vaporization efficiency without excessive flow rates that would waste raw material, thereby improving both productivity and reducing substance loss
3Reliability
If the pressure in the raw material container is increased to improve vaporization, then the vaporization efficiency improves, but the complexity of pressure control and process condition determination increases
Solution Approach 1:
The raw material container system is designed to self-regulate the pressure and vaporization process. The carrier gas flow through the raw material container naturally establishes the pressure conditions needed for efficient vaporization without requiring complex external pressure control mechanisms. The system self-adjusts to maintain optimal vaporization conditions
Solution Approach 2:
The carrier gas supply system serves multiple functions simultaneously: it transports carrier gas to the processing container, vaporizes the raw material in the raw material container, and maintains the appropriate pressure conditions. This multi-functionality eliminates the need for separate pressure control systems, reducing device complexity while maintaining reliable vaporization efficiency
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 the time to stabilize vaporization efficiency, improves throughput, and minimizes raw material loss while ensuring uniformity across multiple substrates, enhancing the reliability of the film forming process.
Implementation Method 1
a liquid or solid raw material (precursor) is vaporized to produce a raw material gas
Implementation Method 2
In the bubbling method, the raw material is vaporized by feeding a carrier gas such as an inert gas into a raw material container filled with a volatile raw material
Implementation Method 3
an exhaust device configured to depressurize and exhaust an inside of the processing container
Implementation Method 4
increasing a pressure inside the raw material container to a first pressure P1 by supplying the carrier gas into the raw material container by the pressure adjusting means
Implementation Method 5
decreasing the pressure inside the raw material container to a second pressure P2 by discarding the raw material gas inside the raw material container via the exhaust bypass path
Implementation Method 6
forming a film by depositing a thin film on an object to be processed using CVD method by supplying the raw material gas into the processing container
Data Source
AI summary
STEP 1 (Pressure increasing step) increases pressure within a raw material container to first pressure by supplying carrier gas to the inside of the raw material container by PCV. STEP 2 (Pressure decreasing step) decreases the pressure within the raw material container to second pressure by operating an exhaust device and discarding the raw material gas from a raw material gas supply pipe via an exhaust bypass pipe. STEP 3 (Stabilization step) stabilizes the vaporization efficiency for vaporizing the raw material inside the raw material container by operating the exhaust device and discarding the raw material gas while introducing the carrier gas into the raw material container. STEP 4 (Film forming step) supplies the raw material gas to the inside of the processing container via the raw material gas supply pipe and deposits a thin film on a wafer by CVD.