Foreline Pressure Control Using Feedback and Gas Injection
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Solution Overview
Problem
Unwanted pressure variation within semiconductor processing chambers leads to process non-uniformity, making it difficult to maintain consistent yields across multiple chambers and introducing undesirable variations in semiconductor manufacturing.
Innovation Solution
A foreline pressure control system that operates independently of the pump, using modulating valves and gas injection, along with pressure feedback control, to maintain desired target set points and reduce pressure fluctuations in the foreline, thereby stabilizing chamber pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pump is used to evacuate processing chambers, then vacuum pressure is achieved, but pressure variations occur that lead to process non-uniformity
Solution Approach 1:
A foreline pressure control system continuously monitors foreline pressure and adjusts a control valve to maintain pressure at a setpoint, creating a closed-loop feedback system that eliminates pressure variations and ensures process uniformity across multiple chambers
Solution Approach 2:
A control valve is introduced as an intermediary component between the pump and the processing chambers to regulate foreline pressure, acting as a mediator that smooths out pressure fluctuations before they affect the chambers
2Device complexity
If multiple processing chambers are connected to a common foreline, then system complexity is reduced, but chamber-to-chamber pressure variations occur
Solution Approach 1:
Individual pressure sensors and control valves are installed for each chamber segment, creating distributed feedback loops that independently regulate pressure in each chamber while sharing a common foreline infrastructure
Solution Approach 2:
The common foreline is segmented into multiple controlled zones with individual control valves for each chamber, allowing independent pressure regulation while maintaining the benefits of a shared foreline structure
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 system achieves improved processing uniformity, increased yield, reduced waste, and lower costs by effectively controlling foreline pressure, ensuring consistent substrate processing across multiple chambers.
Implementation Method 1
A controller is configured to receive communication from a user interface, from a pressure sensor, and to provide communication to a modulating valve and a mass flow controller
Implementation Method 2
A foreline pressure control system that operates independently of the pump, using modulating valves and gas injection, along with pressure feedback control, to maintain desired target set points and reduce pressure fluctuations in the foreline
Implementation Method 3
A foreline pressure control system that operates independently of the pump, using modulating valves and gas injection, along with pressure feedback control, to maintain desired target set points and reduce pressure fluctuations in the foreline
Data Source
AI summary
A system and method for controlling pressure in a foreline of a processing system are disclosed herein that reduce variation in foreline pressure. In one example, a processing system is provided that includes a first process chamber, a first pump, a foreline, and a first foreline pressure control system. The first pump has an inlet and an outlet. The inlet of the first pump coupled to an exhaust port of the first process chamber. The foreline is coupled to the outlet of the first pump. The first foreline pressure control system is fluidly coupled to the foreline downstream of the first pump. The first foreline pressure control system is operable to control a pressure in the foreline independent from operation of the first pump.