ALD Chamber Structure for Uniform Coating of Dome Inner Surfaces
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Solution Overview
Problem
Existing coating technologies face challenges in achieving uniformity and stability for thin-film deposition on the inner surfaces of dome-shaped optical windows, particularly with large aspect ratios, due to limitations in existing ALD equipment design and sensitivity to temperature uniformity.
Innovation Solution
An atomic layer deposition device with a specially configured cabin structure, including a two-stage pressure stabilizing system, active flow guiding, and internal and external synchronous radiative heating, to ensure uniform gas flow and temperature distribution on the inner surfaces of dome-shaped samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional magnetron sputtering or evaporation coating technologies are used, then coating can be achieved on curved surfaces, but the uniformity of the coating is poor and diffraction Newton ring phenomenon occurs
Solution Approach 1:
The patent changes the fundamental deposition mechanism from physical vapor deposition (magnetron sputtering/evaporation) to chemical vapor deposition (ALD), transforming the deposition process from line-of-sight atomic flux to conformal chemical reaction, thereby achieving uniform coating on curved surfaces without Newton ring phenomena
Solution Approach 2:
The patent replaces the mechanical/physical deposition system (magnetron sputtering targets or evaporation sources) with a chemical deposition system (ALD precursors delivering system), where chemical reactions occur conformally on the surface regardless of geometry, eliminating the directional flux issues that cause non-uniformity
2Adaptability or versatility
If the curved-surface radius of the window decreases and the aspect ratio increases, then the difficulty of uniform coating increases, but the film layer uniformity deteriorates drastically and coating cannot be carried out
Solution Approach 1:
The patent designs an ALD deposition system that can universally handle various curved surface geometries (different radii, aspect ratios) by controlling precursor delivery and gas flow, making the same equipment applicable to multiple sample types without requiring geometric matching between source and substrate
Solution Approach 2:
The patent ensures that each local region of the curved surface receives equivalent precursor exposure and reaction conditions through optimized gas flow distribution and precursor delivery, making the deposition process insensitive to variations in local surface geometry
3Manufacturing precision
If existing ALD equipment is used for large-size curved-surface samples, then vapor deposition can be achieved, but uniform heating of the sample is difficult and temperature uniformity is poor
Solution Approach 1:
The patent divides the heating system into multiple independent heating zones (cylindrical heater for vertical temperature gradient control, dome-shaped heater for top surface heating, disc heater for substrate table heating) that can be independently controlled to achieve uniform temperature distribution across large curved surfaces
Solution Approach 2:
The patent introduces a hollow dome-shaped shell as a thermal intermediary that distributes heat uniformly to the curved surface sample, acting as a heat transfer medium that ensures even temperature distribution across the sample surface
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 device achieves uniform and stable thin-film deposition on dome-shaped surfaces, improving the quality of film layers and expanding the applicability of ALD technology to complex curved surfaces with various radii, reducing temperature gradients and enhancing the uniformity of coatings like TiO2, Al2O3, SiO2, and In2O3 on substrates such as glass, quartz, and silicon wafers.
Implementation Method 1
the dome shaped heater covers an upper portion of the dome shaped sample... the disc heater is arranged on a lower surface of the gas extraction plate
Implementation Method 2
internal and external synchronous radiative heating... ensure uniform gas flow and temperature distribution
Implementation Method 3
achieve a bottom-up layered growth mechanism through layer-by-layer surface chemical saturation adsorption reaction
Data Source
AI summary
Provided is an atomic layer deposition device for uniform coating on an inner surface of a dome shaped surface. A gas channel member in the atomic layer deposition device is vertically fixed to a cabin base, and a peripheral edge is arranged on an upper surface of a gas extraction plate in a circumferential direction, and a gas cavity is enclosed by the peripheral edge, a flange and a cover plate. The gas extraction plate is fixed to an upper surface of the gas channel member, and a hollow spherical shell is fixedly arranged on an upper surface of the cover plate. A sample support is sleeved outside the gas channel member, and a dome shaped sample is placed on an annular platform of the sample support. Lower surface of the cabin cover is provided with a dome shaped heater.