Plasma Processing Gas Supply Double Hard Interlock
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Solution Overview
Problem
In plasma processing for semiconductor production, there is a challenge in ensuring stable and safe supply of precursor gases to prevent mixing with process gases, which can lead to particle generation and defects in high-aspect structures, particularly due to the reactivity and inflammability of these gases, and existing soft interlock mechanisms are insufficient for foolproof safety.
Innovation Solution
A plasma processing apparatus with a gas supply unit that includes a double hard interlock system using air-driven valves and solenoid coils to prevent simultaneous flow of precursor and process gases, ensuring safe and stable supply by controlling valve operations through a pressure signal and electrical relay circuit, thereby preventing abnormal reactions and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a soft interlock mechanism is used to control gas valve operations, then the control flexibility and ease of operation are improved, but the safety and reliability are insufficient to prevent gas mixing
Solution Approach 1:
The patent introduces a hard interlock mechanism as an intermediary safety device between the control system and the gas valves. This mechanical interlock physically prevents simultaneous opening of conflicting gas valves, acting as a foolproof mediator that overrides software control and ensures absolute prevention of gas mixing regardless of operator error or system failures.
Solution Approach 2:
The hard interlock mechanism is designed to prevent dangerous situations before they can occur. By establishing a mechanical constraint that makes it physically impossible to open conflicting valves simultaneously, the system provides beforehand protection against gas mixing, eliminating the need for reactive safety measures after a problem occurs.
2Reliability
If a hard interlock system with multiple valves and control mechanisms is implemented, then the safety and reliability are improved, but the device complexity increases
Solution Approach 1:
The gas supply system is segmented into distinct controlled zones with individual valves (first valve, second valve, third valve) for different gas sources. Each valve is independently controlled and monitored, allowing the complex safety requirements to be distributed across multiple simple, modular components rather than requiring a single complex safety mechanism.
Solution Approach 2:
The control unit acts as an intelligent intermediary that manages the complexity of coordinating multiple valves and hard interlock mechanisms. It processes control signals, monitors valve states, and coordinates the operation of multiple gas supply lines, thereby organizing the system's complexity in a manageable and systematic way.
3Manufacturing precision
If the precursor gas is supplied through a shower plate with through-holes, then the distribution uniformity is improved, but the particle generation risk increases due to gas reactions in the through-holes
Solution Approach 1:
The patent extracts the precursor gas supply function from the main process gas supply path by using a separate, dedicated supply line that bypasses the shower plate through-holes. The precursor gas is introduced through a separate valve and delivery mechanism, eliminating the risk of particle generation in the through-holes while maintaining the uniform distribution benefits of the shower plate design for process gases.
Solution Approach 2:
The gas supply system is segmented into separate channels: one for process gases through the shower plate and another for precursor gas through a dedicated line. This segmentation prevents interaction between different gas types in the through-holes, eliminating particle generation risks while preserving the uniform distribution function of the shower plate for its designated gas flow.
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
The double hard interlock system ensures reliable and safe gas supply, preventing particle generation and defects, thereby maintaining production yield and ensuring safe operation of the plasma processing apparatus.
Implementation Method 1
a solenoid coil that acts the air-driven valve
Implementation Method 2
a molecular layer with one layer having strongest physical adsorption force (van der Waals force) that remains even when an exhaust process using an inert gas or the like is performed
Implementation Method 3
controlling valve operations through a pressure signal
Data Source
AI summary
The present invention is a plasma processing apparatus that includes a processing chamber where plasma processing is performed on a sample, a radio frequency power supply that supplies radio frequency power to generate plasma, a sample stage on which the sample is placed, and a gas supply unit that supplies a gas to the processing chamber. The gas supply unit includes a first pipe that supplies a first gas as a gas for etching process to the processing chamber, a second pipe that supplies a second gas as a gas for etching process to the processing chamber, and a third pipe through which a third gas as a gas for deposition process flows. The third pipe is coupled to the second pipe. A fourth valve is arranged on the second pipe. The fourth valve prevents the third gas from flowing in a direction toward a supply source of the second gas.