Maskless Lithography Continuous Scanning Exposure Control
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Solution Overview
Problem
The semiconductor industry lacks efficient and cost-effective methods for three-dimensional structuring of photosensitive materials, particularly in maskless lithography, which often results in unsatisfactory exposure quality and duration due to the need for time-consuming mask production and step processes.
Innovation Solution
A method and device for continuous exposure of image points on a photosensitive material using an optical system, where image points are moved relative to the optical system, and secondary beams are individually controlled to produce specific doses for grey-tone generation, allowing for 2.5 or 3-dimensional photolithographic exposure without the need for masks, using techniques such as DMD mirror switching and mathematical algorithms to adjust radiation intensity and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If maskless lithography with step processes is used, then the need for mask production is eliminated, but the exposure time and process duration become excessively long
Solution Approach 1:
The patent segments the exposure process into multiple beam paths (first and second beam paths) that can operate simultaneously or in rapid succession. Different regions of the photosensitive material are exposed through different beam paths, enabling parallel processing and significantly reducing total exposure time while maintaining maskless operation.
Solution Approach 2:
The patent implements continuous scanning exposure where the beam paths continuously scan across the photosensitive material without interruption. The relative movement between the optical system and substrate enables uninterrupted exposure, eliminating the stop-and-go nature of step processes and dramatically reducing process duration.
2Manufacturing precision
If grey-tone lithography with DMD mirror switching is used, then three-dimensional structuring is enabled, but the exposure process becomes extremely time-consuming
Solution Approach 1:
The patent divides the grey-tone exposure task across multiple beam paths, where each beam path handles specific regions or depth ranges. This segmentation allows simultaneous or overlapping exposure operations, reducing the cumulative time required for multi-layer grey-tone structuring compared to sequential DMD mirror switching.
Solution Approach 2:
The patent employs dynamic beam control where beam paths can be rapidly activated, deactivated, or adjusted in intensity on-the-fly during the exposure process. This dynamic control enables flexible grey-tone generation without requiring time-consuming sequential mirror switching, as beams can be modulated in real-time based on exposure requirements.
3Productivity
If multiple beam paths are used for parallel exposure, then throughput is improved, but the device complexity increases
Solution Approach 1:
The patent designs the optical system with universal components that serve multiple beam paths. Elements such as mirrors, lenses, and control mechanisms are shared across different beam paths, allowing each component to perform multiple functions. This reduces overall device complexity compared to having completely separate optical systems for each beam path.
Solution Approach 2:
The patent merges multiple beam paths into a single integrated optical system with shared resources. Control electronics, scanning mechanisms, and optical elements are combined and coordinated to manage multiple beams simultaneously. This consolidation achieves parallel exposure capability while avoiding the complexity of entirely separate exposure systems.
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 enables efficient, high-volume manufacturing of 2.5 or 3-dimensional structures with improved throughput and reduced costs by eliminating the need for masks and step processes, while enhancing exposure quality through continuous movement and precise control of radiation doses, allowing for targeted grey-tone adjustments and reduced edge effects.
Implementation Method 1
The lithographic techniques in the semiconductor industry can roughly be split up into two large sub-sectors, into imprint lithography and photolithography... in photolithography, use is made in most cases of masks which are intended to project a structure into a photosensitive material
Data Source
AI summary
A method for the exposure of image points of a photosensitive layer comprising a photosensitive material on a substrate by means of an optical system. The method including continuously moving the image points with respect to the optical system; and controlling a plurality of secondary beams by means of the optical system individually for individual exposures of each image point, whereby the secondary beams are put either into an ON state or into an OFF state, wherein a) secondary beams in the ON state produce an individual exposure of the image point assigned to the respective secondary beam and b) secondary beams in the OFF state do not produce any individual exposure of the image point assigned to the respective secondary beam; wherein, for the generation of image points with grey tones n>1, individual exposures are carried out by different secondary beams with individual doses D.