Orifice Plate Hole Area Control via Thermal Oxidation Coating
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Solution Overview
Problem
Conventional mass flow controllers (MFCs) are inadequate for advanced semiconductor fabrication processes, particularly those with features of 20 nm or less, due to insufficient precision and accuracy in gas flow control, which can lead to fluctuations in process gas flow affecting semiconductor wafer processing.
Innovation Solution
A method and system for creating orifice plates with high precision holes, involving initial hole formation, coating with a material that occupies more volume than the original material, and subsequent etching to achieve a final hole with a reduced area, using techniques like thermal oxidation and wet etching to ensure tight tolerances and accurate dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional drilling or laser drilling is used to form holes in orifice plates, then the manufacturing process is simple and fast, but the hole diameter accuracy and tolerance are insufficient for advanced semiconductor fabrication
Solution Approach 1:
The patent applies preliminary action by forming an initial hole with larger dimensions using conventional drilling or laser drilling before applying the coating layer. This initial hole serves as a precursor that will be precisely defined by the subsequent coating and etching processes, allowing the final hole dimensions to be determined by the coating thickness rather than the drilling precision
Solution Approach 2:
The patent replaces the mechanical drilling system with a chemical-coating-based dimensioning system. Instead of relying on mechanical drill bit precision, the hole final dimensions are defined by the thickness of the deposited coating layer, which can be controlled with atomic-layer precision using physical vapor deposition or chemical vapor deposition techniques
2Manufacturing precision
If the coating material occupies greater volume than the consumed material, then the coating effectively reduces the hole area to achieve precision, but the material consumption increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the orifice plate material by depositing a coating layer with different properties (such as silicon dioxide coating on silicon substrate). This parameter change allows the material to be selectively removed in controlled amounts through etching, thereby precisely controlling the final hole area. The volume expansion during coating formation is utilized to create the necessary material removal volume for achieving the target hole dimensions
3Manufacturing precision
If multiple coating and etching cycles are performed to achieve tight tolerances, then the hole diameter variance is reduced to within 400 Angstroms, but the manufacturing time increases
Solution Approach 1:
The patent applies partial action by performing coating and etching cycles only to the extent necessary to achieve the required tolerance of 400 Angstroms or less. The process is iterative but controlled, where each cycle partially refines the hole dimensions. The manufacturing process stops once the specified precision is achieved, avoiding unnecessary additional cycles that would only increase time without improving precision further
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
The method enables the production of orifice plates with holes that have a high degree of accuracy and precision, suitable for advanced semiconductor fabrication processes, improving gas flow control and reducing variance in diameter to achieve tighter tolerance thresholds.
Implementation Method 1
reacting the material of the orifice plate with the reactant comprises performing thermal oxidation of the material of the orifice plate
Implementation Method 2
removing the determined amount of the coating from at least the reduced area hole comprises conducting a wet etch of the coating
Implementation Method 3
forming the initial hole in the orifice plate comprises laser drilling the initial hole in the orifice plate
Data Source
AI summary
Methods and systems for preparing a hole having an accurately controlled area in an orifice plate for a mass flow controller are provided. Methods involve forming an initial hole in the orifice plate. The initial hole has an opening having an initial area. The orifice plate comprises a material that can react to form a coating on the orifice plate. The coating occupies a greater volume than the material consumed to form the coating. The material of the orifice plate is reacted with a reactant to produce the coating and thereby produce a reduced area hole having an opening with a reduced area that is smaller than the initial area. The reduced area hole is measured. A determined amount of the coating is removed from at least the reduced area hole to produce a final hole in the orifice plate, wherein the reduced area is smaller than an opening area of the final hole.