Ejector Design for Uniform Liquid Flow in Semiconductor Etching
Solution Overview
Problem
In semiconductor manufacturing, nonuniform flow velocity distribution of liquid in the substrate treating tank leads to inconsistent treatment of substrates, particularly during etching processes, which can result in undesired etching of films and precipitation issues due to varying silica concentrations.
Innovation Solution
The semiconductor manufacturing apparatus incorporates ejectors with specific passage designs that increase the flow velocity of the liquid and function as diffusers to uniformize solute concentrations, reducing flow velocity distribution variations and preventing silica accumulation, without enlarging the pump, by introducing and re-introducing the liquid through recirculating pipes and the substrate treating tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pump size is increased to increase liquid flow velocity, then the flow velocity of liquid increases, but the device complexity and cost increase
Solution Approach 1:
The patent employs hydraulic principles by designing a recirculating pipe system where liquid flows from the substrate treating tank through the recirculating pipe and is reintroduced at a higher point. This creates a hydraulic loop that utilizes gravity and pressure differentials to maintain flow velocity without requiring an oversized pump, thus resolving the contradiction between flow velocity and device complexity
Solution Approach 2:
The recirculating pipe is positioned to extend from the bottom to the top of the substrate treating tank, utilizing the vertical dimension. This spatial arrangement creates a height difference that generates natural circulation pressure, enabling adequate flow velocity without increasing pump size, thereby resolving the contradiction between flow velocity and device complexity
2Reliability
If the liquid flow velocity is increased to prevent silica accumulation, then silica precipitation is prevented, but the energy consumption increases
Solution Approach 1:
The recirculating pipe system establishes a continuous circulation loop where liquid is constantly moved from the bottom to the top of the tank and flows back down. This continuous circulation prevents silica accumulation by maintaining constant motion and mixing, while the gravitational assist from the vertical arrangement reduces the energy required compared to continuous high-speed pumping
Solution Approach 2:
The system uses the liquid's own weight and the height difference in the recirculating pipe to generate circulation pressure. The liquid essentially pumps itself by falling from the top to the bottom of the tank, reducing external energy input while maintaining flow velocity sufficient to prevent silica precipitation
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 uniform treatment of substrates by stabilizing flow velocity and solute concentrations, preventing nonuniform etching and silica-related issues, thus enhancing the consistency and quality of the semiconductor manufacturing process.
Implementation Method 1
a problem may be caused in the substrate or the liquid due to a flow velocity distribution of the liquid
Implementation Method 2
function as diffusers to uniformize solute concentrations
Data Source
AI summary
In one embodiment, a semiconductor manufacturing apparatus includes a container configured to contain a substrate, and a pipe configured to supply the container with liquid to treat the substrate. The apparatus further includes an ejector including a first passage where the liquid introduced from the pipe and the liquid introduced from the container are joined and pass through, and a first opening configured to eject the liquid that has passed through the first passage. Furthermore, the first passage has an area where a sectional area of the first passage becomes large as advancing downstream in the liquid.