Substrate Etching Flow Control for Stable Molybdenum Film Removal
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Solution Overview
Problem
Existing etching technologies lack controllability in the etching rate of metal films on semiconductor wafers, particularly molybdenum films, due to variations in the concentration of nitrogen dioxide, an intermediate in the etching process.
Innovation Solution
A substrate processing apparatus and method that adjusts the concentration of nitrogen dioxide in the etching liquid by controlling the flow rates of processing liquid and gas supplies, using a controller to manage the flow rate adjusters and gas supplies to regulate the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching technology is used, then the etching process can be performed, but the controllability of the etching rate is poor due to variations in intermediate concentration
Solution Approach 1:
The patent applies parameter changes by controlling the flow rates of processing liquid and gas supplies to regulate the concentration of nitrogen dioxide intermediate in the etching liquid. By adjusting these flow rate parameters, the etching rate becomes controllable and stable, resolving the issue of poor manufacturability precision caused by concentration variations
Solution Approach 2:
The patent implements feedback control through the controller that monitors and adjusts the flow rate adjusters based on the concentration of nitrogen dioxide. This closed-loop feedback mechanism maintains stable intermediate concentration, thereby improving both etching rate controllability and process reliability
2Manufacturing precision
If the concentration of nitrogen dioxide is not controlled, then the etching process is simple, but the etching rate varies and cannot be controlled precisely
Solution Approach 1:
The patent introduces flow rate parameters for processing liquid and gas supplies that can be adjusted to control nitrogen dioxide concentration. This parameter control approach enables precise etching rate control while adding manageable system complexity through flow rate adjusters and a controller
Solution Approach 2:
The patent uses nitrogen dioxide as an intermediary substance whose concentration can be controlled through flow rate adjustments. By managing this intermediate, the system achieves precise etching control without requiring direct manipulation of the etching process itself, balancing precision with acceptable system complexity
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
Enhances the controllability of the etching rate of molybdenum films by precisely managing the concentration of nitrogen dioxide, thereby improving process stability and precision.
Implementation Method 1
The first gas supply is disposed below the substrate within the processing tub, and is configured to discharge a gas to the inside of the processing tub
Implementation Method 2
The second gas supply is disposed inside the overflow tub, and is configured to discharge a gas to an inside of the overflow tub
Implementation Method 3
The liquid feeder is configured to send the processing liquid stored in the overflow tub into the circulation path
Implementation Method 4
The discharge opening group is disposed below the substrate within the processing tub, and serves to discharge the processing liquid to an inside of the processing tub
Implementation Method 5
The controller is configured to perform a concentration adjusting process of adjusting a concentration of an intermediate, which contributes to a reaction of the metal film, on a surface of the substrate by controlling the liquid feeder, the first adjuster and the second adjuster
Data Source
AI summary
A substrate processing apparatus includes a processing tub, a discharge opening group, an overflow tub, a circulation path, a liquid feeder, a first gas supply, a second gas supply, a first adjuster, a second adjuster and a controller. In the processing tub, an etching process is performed by immersing a substrate having a metal film in a processing liquid. The discharge opening group serves to discharge the processing liquid to an inside of the processing tub. The liquid feeder sends the processing liquid stored in the overflow tub into the circulation path. The first gas supply discharges a gas to the inside of the processing tub. The second gas supply discharges a gas to an inside of the overflow tub. The controller is configured to perform adjusting a concentration of an intermediate, which contributes to a reaction of the metal film, on a surface of the substrate.