EUV Substrate Irradiation with Light Amount Suppression
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Solution Overview
Problem
Existing substrate processing technologies face challenges in achieving uniform sensitivity and surface roughness for resist films during EUV lithography, particularly in ensuring even exposure and maintaining spectral integrity of vacuum ultraviolet light.
Innovation Solution
A substrate processing apparatus that includes a light source emitting vacuum ultraviolet light and a light amount suppressing member, such as a perforated plate, to adjust the light intensity and create a gradient of irradiation, ensuring the light is weak and evenly distributed across the substrate surface before exposure, using a light-shielding member to form an irradiation region that increases towards the outer peripheral side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a light source irradiates a substrate with vacuum ultraviolet light before exposure, then the sensitivity and surface roughness of resist patterns are improved, but the light intensity becomes too strong causing non-uniform exposure across the substrate surface
Solution Approach 1:
The light source is divided into multiple independent light emitting units arranged in an array. Each unit can be individually controlled to emit vacuum ultraviolet light, allowing the overall light distribution to be optimized by adjusting individual unit intensities. This segmentation enables uniform light distribution across the substrate surface while maintaining the beneficial effects of VUV irradiation on resist pattern quality.
Solution Approach 2:
Different regions of the substrate surface receive different light intensities through independent control of light emitting units. The light intensity is locally adjusted to ensure uniform exposure across the entire substrate, with each position receiving appropriate irradiation strength. This local quality control allows the light intensity to be optimized for each region while maintaining overall uniformity.
2Manufacturing precision
If strong vacuum ultraviolet light is used to improve exposure sensitivity, then the sensitivity of resist film is enhanced, but the spectral components of the light are altered causing loss of spectral integrity
Solution Approach 1:
A monochromator is introduced as an intermediary device between the light source and the substrate. The monochromator selects and transmits only the required vacuum ultraviolet wavelength components (10-200 nm) while blocking other wavelengths. This ensures that the spectral integrity of the VUV light is maintained during irradiation, allowing exposure sensitivity to be enhanced without introducing unwanted spectral components that would alter the light's properties.
3Area of stationary object
If the light amount is increased to ensure adequate coverage of the substrate surface, then the irradiation coverage is improved, but the light becomes too intense causing non-uniform sensitivity across different regions
Solution Approach 1:
The illumination system is segmented into multiple independently controllable light emitting units that can be selectively activated. By controlling which units are on and adjusting their individual intensities, the system achieves both adequate coverage area and uniform light distribution across the substrate surface.
Solution Approach 2:
The light emitting units are arranged to move relative to the substrate surface, dynamically adjusting the irradiation pattern. This dynamic arrangement allows the light coverage area to be optimized while maintaining uniform intensity distribution, as the moving units can be positioned to ensure even illumination across different regions of the substrate.
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 uniform sensitivity adjustment and improved surface roughness of resist patterns by irradiating the substrate with weak vacuum ultraviolet light, enhancing exposure sensitivity and pattern quality while maintaining the spectral integrity of the light.
Implementation Method 1
a light source configured to irradiate a substrate having thereon a resist film made of a resist material for EUV lithography with light including vacuum ultraviolet light
Implementation Method 2
a light amount suppressing member provided in an optical path of the light from the light source and configured to suppress an amount of the light reaching a surface of the substrate such that the light becomes weak light as a whole in an irradiation region
Data Source
AI summary
A substrate processing apparatus includes light source configured to irradiate a substrate having thereon a resist film made of a resist material for EUV lithography with light including vacuum ultraviolet light before an exposure process, and a light amount suppressing member provided in an optical path of the light from the light source and configured to suppress an amount of the light reaching a surface of the substrate such that the light becomes weak light as a whole in an irradiation region, wherein the light including the vacuum ultraviolet light contains a continuous spectral component of at least a portion of a band contained in a wavelength of 10 nm to 200 nm.