Substrate Process Apparatus Dual Evacuation Flow Control
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Solution Overview
Problem
In semiconductor and LCD/FPD substrate processing, existing vacuum chamber systems face challenges in maintaining uniform gas flow and pressure control, leading to intermixing of reaction gases and degradation of film deposition or etching uniformity due to the inability to accurately measure gas flow rates through evacuation lines.
Innovation Solution
A substrate process apparatus with first and second evacuation passages, conductance adjustment, and differential pressure measurement, allowing for precise adjustment of gas flow rates and pressures to prevent gas intermixing, using a butterfly valve and data storage to optimize gas flow during processes like ALD and MLD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If pressure gauges are provided in evacuation lines to control pressure, then pressure control is achieved, but gas flow rate measurement precision deteriorates because flow rates cannot be directly measured
Solution Approach 1:
A flow rate measurement instrument is introduced as an intermediary device installed in parallel with the pressure gauge in the evacuation line. This intermediary instrument directly measures the flow rate of reaction gas, providing accurate flow rate data without interfering with the pressure control function of the pressure gauge. The dual-instrument approach allows simultaneous acquisition of both pressure and flow rate parameters.
Solution Approach 2:
The control system is enhanced to handle multiple measurement functions simultaneously. By integrating both pressure gauge readings and flow rate measurement instrument data into a unified control mechanism, the system achieves multi-functionality in monitoring evacuation line conditions, enabling comprehensive control based on both pressure and flow rate parameters.
2Stress or pressure
If pressure control valves are adjusted to equalize pressure readings in evacuation lines, then pressure uniformity is achieved, but gas flow uniformity deteriorates due to vacuum pump performance degradation or deposit accumulation
Solution Approach 1:
Flow rate measurement instruments are installed in each evacuation line to provide real-time feedback on actual gas flow rates. The control system uses this feedback information to detect deviations caused by vacuum pump performance degradation or deposit accumulation, and automatically adjusts pressure control valves to compensate for these changes, maintaining stable gas flow uniformity despite varying pressure conditions.
Solution Approach 2:
The system transitions from static pressure-based control to dynamic flow-rate-aware control. By continuously monitoring flow rates and adjusting evacuation line parameters in real-time based on actual flow conditions, the system adapts to changing circumstances such as pump degradation or deposit formation, maintaining gas flow uniformity under varying operational states.
3Productivity
If reaction gases are evacuated through multiple evacuation lines, then gas evacuation efficiency is improved, but gas intermixing occurs when flow rates are not properly controlled
Solution Approach 1:
Flow rate measurement instruments in each evacuation line provide real-time feedback on gas flow rates. The control system uses this information to independently regulate the flow of reaction gases through different evacuation lines, ensuring that gases are evacuated at appropriate rates without intermixing, while maintaining high overall evacuation efficiency through optimized multi-line operation.
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 solution ensures stable and uniform gas flows across wafers, maintaining high across-wafer and wafer-to-wafer uniformity in film deposition and etching processes by accurately controlling gas flow rates and pressures, preventing gas intermixing and particle generation.
Implementation Method 1
a differential pressure measurement portion that measures a differential pressure between the primary side and the secondary side of the conductance adjustment portion
Implementation Method 2
the vacuum chamber is evacuated to reduced pressures through plural evacuation lines. In such a case, vacuum pumps are connected to the corresponding evacuation lines
Data Source
AI summary
A vacuum chamber is evacuated through a first evacuation passage provided with a first valve and a second evacuation passage provided with a second valve. An opening degree of the first valve is adjusted so that a pressure in the vacuum chamber becomes substantially equal to a process pressure P; an opening degree of a butterfly valve further provided in the second evacuation passage is adjusted to substantially equal to a set value determined by a table in order to set flow rates of gases to be evacuated through the first evacuation passage and the second evacuation passage to be substantially equal to corresponding set values determined by the recipe; and an opening degree of the second valve is adjusted so that a measurement value of a differential pressure gauge further provided in the second evacuation passage becomes substantially equal to a differential pressure written in the table.