Ceramic Heater Purge Gas Flow Uniformity
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Solution Overview
Problem
Existing ceramic heaters with a purge function suffer from non-uniform gas flow rates and amounts ejected from lateral holes, leading to inefficiencies in preventing process gas from reaching the wafer surface during semiconductor manufacturing.
Innovation Solution
A ceramic heater design with a cylindrical shaft and a disk-like ceramic plate featuring an arc-shaped gas groove, vertically arranged gas introduction holes of varying diameters, and lateral holes that reach the outer periphery, ensuring uniform gas flow rates by differing the diameters of at least one gas introduction hole from others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If gas introduction holes are arranged at different distances from the shaft hole, then the purge function can cover a wider area, but the gas flow rates become non-uniform
Solution Approach 1:
The patent applies local quality by varying the diameter of gas introduction holes based on their position relative to the shaft hole. Holes closer to the shaft hole have smaller diameters, while holes farther away have larger diameters. This local differentiation compensates for the distance effect, ensuring uniform gas flow rates across all holes despite their different positions, thereby resolving the contradiction between wide coverage and flow uniformity.
Solution Approach 2:
The patent changes the parameter of hole diameter to compensate for variations in distance from the shaft hole. By adjusting the diameter parameter of each gas introduction hole according to its position, the system maintains uniform gas flow rates while achieving wide-area purge coverage. This parameter adjustment resolves the contradiction by making the hole diameter a function of its radial position.
2Device complexity
If all gas introduction holes have the same diameter, then the structure is simpler, but gas amounts ejected from lateral holes become non-uniform
Solution Approach 1:
The patent applies local quality by making each gas introduction hole have a diameter tailored to its specific position in the gas groove. Instead of uniform diameters, each hole's diameter is locally optimized based on its distance from the shaft hole, ensuring that gas amounts ejected from all lateral holes are uniform. This resolves the contradiction by sacrificing structural simplicity for ejection uniformity.
Solution Approach 2:
The patent introduces asymmetry by varying the diameters of gas introduction holes according to their positions. The asymmetric diameter distribution compensates for the asymmetric distances from the shaft hole, ensuring uniform gas flow. This asymmetric design resolves the contradiction between structural simplicity and ejection uniformity.
3Ease of manufacture
If gas flow rates to different lateral holes are non-uniform, then the structure is easier to manufacture, but the purge function effectiveness decreases
Solution Approach 1:
The patent applies local quality by varying the diameter of gas introduction holes based on their position to ensure uniform gas flow rates. This local differentiation maintains purge function effectiveness while remaining manufacturable through standard ceramic processing techniques. The solution resolves the contradiction by making hole diameter a position-dependent parameter.
Solution Approach 2:
The patent changes the diameter parameter of gas introduction holes to compensate for positional variations. By adjusting this parameter based on distance from the shaft hole, the system ensures uniform gas flow rates to all lateral holes, maintaining purge effectiveness. This parameter optimization resolves the contradiction between ease of manufacture and functional reliability.
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 configuration effectively uniformizes gas flow rates and amounts ejected from lateral holes, enhancing the purge function's effectiveness in preventing process gas from reaching the wafer surface, thereby improving the semiconductor manufacturing process.
Implementation Method 1
a ceramic heater including a ceramic plate on which a wafer is to be placed, and a cylindrical ceramic shaft attached to the ceramic plate... a disk-like ceramic plate... embedded with a heater electrode
Implementation Method 2
a gas groove provided in an arc shape on the second surface of the ceramic plate, and configured to form, together with an upper end surface of the ceramic shaft, a gas passage communicating with the shaft hole... gas supplied to the shaft hole is ejected to the outer peripheral portion of the ceramic plate through the shaft hole, the gas groove, the plurality of gas introduction holes, and the plurality of lateral holes in order
Data Source
AI summary
There is provided a ceramic heater including a ceramic plate embedded with a heater electrode; a ceramic shaft on a second surface of the ceramic plate; a shaft hole in a side wall constituting the ceramic shaft, to penetrate through the ceramic shaft; a gas groove in an arc shape on the second surface, and configured to form a gas passage communicating with the shaft hole; gas introduction holes provided in a vertical direction just above the gas groove to communicate therewith, and arranged apart from each other in a longitudinal direction of the gas groove; and lateral holes provided in a lateral direction from the gas introduction holes, and configured to reach a first surface of the ceramic plate. At least one of the gas introduction holes has a diameter different from those of the other gas introduction holes, to uniformize gas flow rates in the gas introduction holes.