Anti-Reflective Coating for Transparent End Effector Light Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing workpiece supports in semiconductor device fabrication systems, such as those using clear quartz, can block light energy from heating elements like tungsten halogen bulbs or LEDs, leading to temperature non-uniformity in the workpiece, with portions above the support being significantly cooler than the rest.
Innovation Solution
Coating the workpiece support with an anti-reflective material, such as magnesium fluoride or multi-layer optical coatings, to improve light transmission and reduce reflection, ensuring more efficient energy transfer and temperature uniformity across the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent workpiece support (clear quartz) is used to allow light transmission, then light energy transmission is improved (88% transmission), but temperature uniformity deteriorates (50°C cooler region above support)
Solution Approach 1:
The patent applies an anti-reflective coating to the workpiece support surface to change the optical parameters of the interface. This coating reduces reflection losses and increases light transmission through the support, thereby improving temperature uniformity across the workpiece while maintaining the transparent support structure.
2Loss of energy
If a transparent material (clear quartz) is used for workpiece support, then light blocking is reduced (88% transmission), but reflection losses increase (12% loss)
Solution Approach 1:
The anti-reflective coating modifies the surface optical parameters to reduce reflection coefficients. By changing the refractive index matching at the air-quartz interface through the coating, the patent minimizes reflection losses and maximizes light transmission through the transparent support.
3Temperature
If heating elements are placed below the workpiece support, then workpiece heating is achieved, but support heat absorption increases (reducing light transmission)
Solution Approach 1:
The anti-reflective coating acts as an intermediary layer that facilitates efficient energy transfer from the heating elements through the support to the workpiece. The coating reduces interfacial reflection, allowing more thermal energy to pass through the transparent support while minimizing heat absorption by the support itself.
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 anti-reflective coating increases light transmittance by at least 5-10% across the relevant wavelengths, enhancing temperature uniformity and reducing the workpiece support's temperature by minimizing heat absorption, thus improving the heating process efficiency.
Implementation Method 1
A workpiece support, such as an end effector, is coated on at least one of its surfaces with an anti-reflective material. The anti-reflective material improves the transmission of light through the workpiece support.
Implementation Method 2
the reduced reflection from the workpiece support may minimize the temperature increase on the portion of the workpiece disposed above the workpiece support
Implementation Method 3
Power from tungsten halogen bulbs is emitted at wavelengths ranging from about 400 nm to 2600 nm... LED lights may provide the thermal energy... the anti-reflective material allows more efficient energy transfer from the heating elements to the workpiece
Data Source
AI summary
A workpiece support, such as an end effector, is coated on at least one of its surfaces with an anti-reflective material. The anti-reflective material improves the transmission of light through the workpiece support. The workpiece support may be disposed in a chamber, with heating elements disposed beneath the workpiece support, such that the workpiece support is disposed between the heating elements and the workpiece. In certain embodiments, the heating elements may be LEDs or tungsten halogen lamps. The anti-reflective material allows more efficient energy transfer from the heating elements to the workpiece. This may result in improved temperature uniformity across the workpiece. The anti-reflective material may be magnesium fluoride or a multi-layer optical coating. Alternatively, the heating elements may be disposed above the workpiece. In this case, the reduced reflection from the workpiece support may minimize the temperature increase on the portion of the workpiece disposed above the workpiece support.