Substrate Processing Apparatus Silicon Concentration Control
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in accurately adjusting the silicon concentration in phosphoric acid aqueous solutions for selective etching of silicon nitride films, as silicon particles added to the solutions either aggregate or get caught by filters, leading to inconsistent etching rates.
Innovation Solution
A substrate processing apparatus and method that includes a production tank with a bypass path and filter system, where silicon particles are initially dispersed without flowing through the filter to prevent aggregation, and then filtered to remove impurities, ensuring uniform silicon concentration and accurate etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If silicon particles are added to phosphoric acid aqueous solution to adjust silicon concentration, then the etching rate can be controlled, but the silicon particles aggregate and cannot be uniformly dispersed
Solution Approach 1:
The patent applies preliminary action by adding a surfactant to the phosphoric acid aqueous solution before adding silicon particles. The surfactant pre-establishes a stable environment that prevents particle aggregation, ensuring uniform dispersion from the beginning rather than attempting to disperse aggregated particles later.
Solution Approach 2:
The surfactant acts as an intermediary substance between the silicon particles and the phosphoric acid aqueous solution. It mediates the interaction by adsorbing onto the particle surfaces and providing steric or electrostatic repulsion, preventing direct aggregation between particles while allowing them to remain suspended uniformly in the solution.
2Manufacturing precision
If silicon particles are added to phosphoric acid aqueous solution stored in tank, then silicon concentration can be adjusted, but the particles are caught by the filter and cannot be dispersed
Solution Approach 1:
The patent applies preliminary action by adding the surfactant to the phosphoric acid aqueous solution in the tank before the silicon particles are introduced. This pre-treatment ensures that when particles are added, they are immediately stabilized and prevented from aggregating into filter-clogging clusters, allowing them to pass through the filter uniformly.
Solution Approach 2:
The surfactant serves as an intermediary that protects silicon particles from being caught by the filter. By coating the particle surfaces, it reduces their tendency to aggregate and adhere to filter media, enabling reliable filtration while maintaining particle suspension and uniform concentration distribution.
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 approach allows for the stable and accurate production of processing liquids with uniform silicon concentration, enabling precise selective etching of silicon nitride films, improving the efficiency and accuracy of the etching process.
Implementation Method 1
a filter that removes impurities in the processing liquid produced by the processing liquid producer
Implementation Method 2
a circulation system that circulates the processing liquid in the production tank through the filter
Implementation Method 3
a dispersion state determinator that determines whether silicon particles in the processing liquid circulated by the circulation system are dispersed to a predetermined degree
Data Source
AI summary
A phosphoric acid aqueous solution in a production tank circulates a circulation system. The circulation system is configured to be switchable between a first state in which the phosphoric acid aqueous solution is circulated through a bypass pipe and a second state in which the phosphoric acid aqueous solution is circulated through a filter. When a silicon containing liquid is supplied to the production tank, the circulation system is switched to the first state. When silicon particles are uniformly dispersed in the phosphoric acid aqueous solution, the circulation system is switched to the second state. Alternatively, a filtration member is provided in the production tank. The silicon containing liquid is stored in the filtration member. The filtration member is dipped in the phosphoric acid aqueous solution stored in the production tank. The silicon containing liquid is permeated through the filtration member, and is mixed with the phosphoric acid aqueous solution.