Maskless Lithography Tilting Axis Orientation
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Solution Overview
Problem
Conventional mask-based lithographic systems are inflexible and costly to modify, limiting their ability to quickly change patterns on substrates like ICs and flat panel displays, whereas maskless systems with programmable patterning devices are more efficient but face challenges in accurately exposing substrates due to irregularities in radiation spot patterns.
Innovation Solution
A method and system utilizing an array of individually controllable elements that tilt to generate a patterned radiation beam, with the tilting axis perpendicular to the scanning direction, allowing for precise exposure control and accurate pattern projection onto substrates, and incorporating a microlens array and pinhole array to reduce cross-talk between radiation spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional mask-based lithographic system is used, then pattern stability and manufacturing precision are maintained, but flexibility and adaptability to change patterns are poor and cost is high
Solution Approach 1:
The patent employs a programmable patterning device with individually addressable elements that can dynamically change their state (on/off, different gray levels) to generate different patterns without physical mask changes. This dynamic reconfigurability provides flexibility while maintaining precision through controlled element activation.
Solution Approach 2:
The invention changes the operational parameters of the patterning device by selectively activating different elements in the array and controlling their individual states. This allows pattern variation through parameter control rather than physical mask replacement, achieving both adaptability and precision.
2Adaptability or versatility
If a maskless system with programmable patterning device is used, then flexibility and cost efficiency are improved, but exposure accuracy deteriorates due to irregularities in radiation spot patterns
Solution Approach 1:
The patent applies local quality control by individually addressing and controlling each element in the patterning device array. Each element can be independently activated or deactivated, allowing precise local pattern formation while compensating for irregularities through selective element control.
Solution Approach 2:
The invention incorporates feedback mechanisms to detect and correct irregularities in radiation spot patterns. By monitoring the actual pattern output and adjusting element activation accordingly, the system maintains exposure accuracy while preserving the flexibility of maskless operation.
3Ease of manufacture
If individually addressable elements are used to generate patterns, then manufacturing cost and time for pattern changes are reduced, but device complexity increases
Solution Approach 1:
The patent replaces mechanical mask handling systems with an electronically controlled programmable patterning device. This substitution eliminates the need for physical mask fabrication, storage, and changeover, reducing manufacturing complexity and cost while enabling rapid pattern changes through electronic programming.
4Device complexity
If the tilting axis is not perpendicular to the scanning direction, then pattern generation is simpler, but cross-talk between adjacent radiation spots increases
Solution Approach 1:
The patent deliberately introduces asymmetry by orienting the tilting axis perpendicular to the scanning direction. This asymmetric configuration, while adding some geometric complexity, effectively minimizes cross-talk between adjacent radiation spots by ensuring that tilted beams from one element do not interfere with spots generated by neighboring elements during scanning.
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 enhances the flexibility and accuracy of substrate exposure in maskless lithography, enabling efficient and precise pattern generation on substrates with reduced cross-talk, thus improving the overall performance and efficiency of the lithographic process.
Implementation Method 1
imparting the radiation beam by an array of individually controllable elements; generating, from the radiation beam, a patterned radiation beam, by tilting the individually controllable elements between different positions about a tilting axis
Implementation Method 2
a projection system comprising a microlens array, the microlens array being configured to: project a first two-dimensional pattern of radiation spots and a first two-dimensional pattern of radiation spots onto the substrate
Implementation Method 3
wherein the pinhole array is arranged in an optical path of the patterned radiation beam between the first microlens array and the second microlens array, and wherein the pinhole array is configured to limit cross-talk between adjacent radiation spots projected onto the substrate
Data Source
AI summary
Method of exposing a substrate by a patterned radiation beam, comprising: —providing a radiation beam; —imparting the radiation beam by an array of individually controllable elements; —generating, from the radiation beam, a patterned radiation beam, by tilting the individually controllable elements between different positions about a tilting axis; —projecting the patterned radiation beam towards a substrate; —scanning a substrate across the patterned radiation beam in a scanning direction so as to expose the substrate to the patterned radiation beam, whereby the tilting axis of the individually controllable elements is substantially perpendicular to the scanning direction.