Systems and methods for multi-photon lithography of a substrate material

Abstract

A multi-photon lithography system and method including an optical pulse source generating a pulsed light beam, line-forming optics producing a line-shaped beam having an elongated cross-section, a scanning system directing the line-shaped beam across a scan range, and a digital mask system including an array of addressable elements modulating the line-shaped beam according to a spatial pattern. Projection optics receive modulated light from the digital mask system and project the modulated light toward a patterning plane, and an objective lens focuses the light onto the patterning plane within a substrate material. A controller coordinates operation of the scanning system and the digital mask system to pattern the substrate material via multi-photon absorption.

Description

IRRA-M05-PCTSYSTEMS AND METHODS FOR MULTI-PHOTON LITHOGRAPHY OF A SUBSTRATE MATERIALCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This Application claims the benefit of U.S. Provisional Application No.63 / 776,768, filed on 24-MAR-2025, titled, “SYSTEMS AND METHODS FOR MULTIPHOTON LITHOGRAPHY OF A SUBSTRATE MATERIAL”, which is incorporated in its entirety by this reference.TECHNICAL FIELD

[0002] This invention relates generally to the field of multi-photon lithography, and more specifically to a new and useful system and method for multi -photon lithography of a substrate material.BACKGROUND OF THE INVENTION

[0003] Multi-photon lithography enables fabrication of three-dimensional structures at sub-micron resolution by selectively polymerizing or otherwise altering a photosensitive substrate material through nonlinear optical absorption. Unlike singlephoton lithography, multi -photon processes confine material alteration to a small focal volume where photon density is sufficiently high, enabling true volumetric patterning without the need for layer-by-layer deposition.

[0004] Conventional multi-photon lithography systems pattern substrate materials by scanning a tightly focused spot through the material point-by-point. While this approach can achieve high spatial resolution, the serial nature of point-scanning limits throughput, particularly for large-volume structures. Line-scan approaches have been explored to increase patterning speed by focusing light into a line rather than a point and scanning the line across the substrate material. However, existing line-scan systemsl ot 82IRRA-M05-PCT face challenges in achieving high throughput while maintaining adequate resolution and patterning flexibility. These challenges include limitations in scanning speed, constraints imposed by digital mask refresh rates, difficulties in controlling exposure across patterned regions, and stitching errors when patterning volumes larger than a single field of view.

[0005] Thus, there is a need in the multi-photon lithography field to create a new and useful system and method for multi-photon lithography of a substrate material. This invention provides such a new and useful system and method.BRIEF DESCRIPTION OF DRAWINGS

[0006] FIG. 1 is a schematic block diagram of a multi-photon lithography system according to one variation.

[0007] FIG. 2 is a schematic block diagram of a multi-photon lithography system variation incorporating multiple DMDs and a shared scanner element.

[0008] FIG. 3 is a schematic diagram illustrating a polygon scanning configuration with a digital micromirror device oriented for a blazed grating condition.

[0009] FIG.4A is a schematic diagram illustrating a first DMD orientation option with the DMD rotated 45 degrees for a blazed condition.

[0010] FIG.4B is a schematic diagram illustrating a second DMD orientation option with the DMD in a standard orientation optimized for a blazed condition.

[0011] FIG.5A is a three-dimensional perspective schematic illustrating combining light from multiple DMDs using a knife-edge mirror.

[0012] FIG.5B is a schematic top-down view illustrating the knife-edge mirror combining configuration with an imaging microscope for in-situ monitoring.

[0013] FIG. 6 is a schematic diagram illustrating combining light from multiple DMDs using a concave mirror.

[0014] FIG. 7 is a schematic diagram illustrating a time-multiplexed configuration for switching between DMD blocks using electro-optic modulators and polarization beam splitters.IRRA-M05-PCT

[0015] FIG. 8A is a block diagram illustrating data flow for high-speed pattern streaming using an FPGA controller.

[0016] FIG. 8B is a schematic diagram illustrating super-pixel binning patterns on a DMD for grayscale control.

[0017] FIG. 8C is a schematic diagram illustrating a DMD-to-DMD mapping concept for grayscale control, showing how pixels from a first DMD map to pixels on a second DMD.

[0018] FIG. 8D is a schematic diagram illustrating an optical configuration for implementing DMD-to-DMD mapping for grayscale control.

[0019] FIG. 9 is a schematic diagram illustrating an active beam shaping configuration using a spatial light modulator with metrology feedback.

[0020] FIG. 10 is a schematic diagram illustrating a passive beam shaping configuration using polarization-based beam splitting.

[0021] FIG. 11 is a schematic diagram illustrating a tilted patterning plane configuration showing an objective lens focusing onto a tilted wafer with vertical and lateral stage translation.

[0022] FIG. 12 is a schematic diagram illustrating an exemplary stage configuration for substrate positioning.

[0023] FIG. 13 is a schematic diagram illustrating a remote focal plane manipulation and tilt compensation using a deformable mirror or phase plate.

[0024] FIG. 14A is a schematic diagram illustrating a pump-probe delay configuration using a Mach-Zehnder interferometer with a delay stage for reducing patterning pulse energy.

[0025] FIG. 14B is a schematic diagram illustrating a pump-probe delay configuration with second harmonic generation using a BBO crystal in one arm and a delay stage in the other arm.

[0026] FIG. 15A is a schematic diagram illustrating burst mode laser operation with multiple pulses per burst.

[0027] FIG. 15B is a schematic diagram illustrating pulse shaping options for shaped pulse trains.IRRA-M05-PCT

[0028] FIG. 16A is a schematic diagram illustrating an optical configuration for activation-deactivation patterning using an optical parametric amplifier.

[0029] FIG. 16B is a schematic diagram illustrating the activation-deactivation patterning process for resolution enhancement.

[0030] FIG. 17 is a schematic diagram illustrating a multiple laser combining configuration for increasing effective repetition rate.

[0031] FIG. 18 is a block diagram illustrating a control system architecture showing input signal options, control system compute resources, and output signal options according to various variations.

[0032] FIG. 19 is a flowchart illustrating a method for multi-photon lithography according to one variation.

[0033] FIG. 20 is a flowchart illustrating a method variation for directing light to multiple DMDs.

[0034] FIG. 21 is a flowchart illustrating a method variation for variable exposure patterning.

[0035] FIG. 22 is a flowchart illustrating a method variation for tilted patterning plane operation.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The following description of the embodiments of the invention is not intended to limit the invention to these embodiments but rather to enable a person skilled in the art to make and use this invention.1. Overview

[0037] Described herein are systems and methods for multi-photon lithography of a substrate material. The systems and methods use a scanning approach in which an optical pulse source generates a pulsed light beam that is shaped by beam-forming optics and scanned across a digital mask by a scanning system. In some variations, the line-forming optics produce a line-shaped beam having an elongated cross-section thatIRRA-M05-PCT is scanned across the digital mask. In other variations, the optical form may span an MxN matrix of illumination points, where M is greater than or equal to 2 and N is greater than or equal to 1, enabling patterning with a line (where N equals 1) or an array of parallel lines (where N is greater than i). The digital mask modulates the shaped beam according to a spatial pattern. Projection optics and an objective lens focus the modulated light onto a patterning plane within a substrate material. In many variations, multi-photon absorption alters the material according to the projected pattern. A controller coordinates operation of the scanning system and the digital mask to achieve high-throughput patterning of three-dimensional structures.

[0038] The systems and methods may be used for lithographic patterning of substrate materials for construction of three-dimensional nano-fabricated structures. In particular, the systems and methods may be used for formation of volumetric, semifreeform, or fully freeform structures. Applications may include fabrication of optical components (e.g., gradient-index optics, diffractive neural networks, waveguides), microfluidic devices, scaffolds for biological applications, and other structures benefiting from arbitrary three-dimensional patterning at sub-micron resolution. The systems and methods may alternatively be used for any suitable application.

[0039] Transitioning multi -photon lithography from laboratory demonstration to reliable, scalable industrial production introduces numerous challenges. To address these challenges, the systems and methods described herein may incorporate one or more variations and configuration options that may be implemented independently or in combination. Variations related to throughput and duty cycle may include but are not limited to: multiple digital mask architectures enabling switching between masks during refresh cycles or tiling masks for enlarged fields of view; polygon scanner configurations for high-speed continuous scanning; and delay line configurations for increasing effective pulse repetition rate. Variations related to patterning capability may include but are not limited to: tilted patterning plane configurations enabling continuous three-dimensional volume patterning with reduced stitching boundaries; variable exposure control for achieving a plurality of discrete exposure levels within patterned structures; and tilted line-scan orientations for efficient digital mask utilization in blazed grating configurations. Variations related to precision and quality control may include but areIRRA-M05-PCT not limited to: active beam profile correction using spatial light modulators with sensor feedback; active alignment using position feedback to reduce stitching errors; in-situ phase measurement for verifying patterning results layer-by-layer; and substrate registration for aligning patterning to existing structures. Variations related to system configuration may include but are not limited to: various stage configurations for nonCartesian patterning geometries; remote focusing for rapid axial repositioning without moving the objective or substrate; dispersion control for temporal focusing configurations; and specialized control systems including FPGA-based controllers for sustained high-speed digital mask operation. These variations address practical challenges of industrial multi -photon lithography and maybe selectively combined based on application requirements.

[0040] The systems and methods are primarily described for multi-photon lithography, and in particular for two-photon lithography. However, the systems and methods may apply to other nonlinear optical patterning processes and may be adapted for use with different substrate materials, optical configurations, and patterning applications.

[0041] The system and method may provide a number of potential benefits. The system and method are not limited to always providing such benefits and are presented only as exemplary representations for how the system and method maybe put to use. The list of benefits is not intended to be exhaustive and other benefits may additionally or alternatively exist.

[0042] As one potential benefit, the systems and methods may increase patterning throughput compared to point-scanning approaches. By shaping the pulsed light beam into a line and scanning the line across a digital mask, the systems and methods may pattern an entire line of voxels simultaneously rather than addressing each voxel individually. When combined with multiple digital mask configurations (e.g., multiple DMDs that can be switched between or tiled together), the systems and methods may further increase throughput by reducing downtime associated with digital mask refresh cycles.

[0043] As another potential benefit, the systems and methods may reduce stitching errors or aberrations when patterning volumes larger than a single field of view. ByIRRA-M05-PCT configuring the patterning plane at a tilt angle with respect to the substrate material, the systems and methods may pattern a three-dimensional volume with thickness greater than the axial resolution of a single voxel during continuous lateral translation. This may enable longer continuous sweeps compared to approaches that scan through the axial direction before moving laterally, thereby reducing the number of stitching boundaries. Active alignment using position feedback may further reduce stitching errors by adjusting patterning location based on measured stage position.

[0044] As another potential benefit, the systems and methods may achieve a plurality of discrete exposure levels within patterned regions. By coordinating patterning across multiple sweeps at different power levels (e.g., binary-weighted power levels achieving 2AN exposure levels in N sweeps), the systems and methods may produce gradient structures with spatially varying material properties. This may enable fabrication of gradient-index optical components and other structures where controlled variation in exposure is desired.

[0045] As another potential benefit, the systems and methods may improve utilization of a digital mask such as a DMD. By orienting the line-shaped beam at a tilt angle (e.g., greater than 30 degrees) with respect to the scan direction such that the focal line aligns with a pixel array axis of the digital mask, the systems and methods may operate in a blazed grating condition while utilizing a greater portion of the digital mask area compared to non-tilted configurations.

[0046] As another potential benefit, the systems and methods may address operational demands of digital masks that approach or exceed typical operating parameters. High-throughput multi -photon lithography may require digital mask refresh rates and sustained data throughput beyond standard operating conditions. The systems and methods may address these demands through variations such as: switching between multiple digital masks to allow refresh time while maintaining continuous patterning; FPGA-based control systems capable of streaming pattern data at sustained rates of 10 kHz or higher; and coordinated timing between the scanning system and digital mask to synchronize pattern updates with scan position.

[0047] As another potential benefit, the systems and methods may maintain consistent beam quality during scanning. By using a spatial light modulator with sensorIRRA-M05-PCT feedback to actively correct for aberrations, the systems and methods may achieve more uniform illumination across the patterning field and compensate for variations that may occur during scanning or due to manufacturing tolerances in digital mask components.

[0048] As another potential benefit, the systems and methods may enable in-situ quality control during the patterning process. By measuring optical path length through the substrate material after each patterning pass and determining a phase profile of each patterned region by subtracting successive measurements, the systems and methods may verify patterning results without removing the substrate material from the lithography system.2. System

[0049] As shown in FIGS. 1 and 2, a multi-photon lithography system 100 may include an optical pulse source 110 generating a pulsed light beam, line-forming optics 120 receiving the pulsed light beam and producing a line-shaped beam having an elongated cross-section, a scanning system 130 receiving the line-shaped beam and directing the line-shaped beam across a scan range, a digital mask system 140 receiving the line-shaped beam from the scanning system 130, projection optics 150 receiving modulated light from the digital mask system 140, an objective lens 160 focusing the light onto a patterning plane within a substrate material 170, and a controller 180 coordinating operation of the scanning system 130 and the digital mask system 140. The digital mask system 140 may include an array of individually addressable elements that modulate the line-shaped beam according to a spatial pattern. The controller 180 coordinates the scanning system 130 and digital mask system 140 to pattern the substrate material 170 via multi-photon absorption.

[0050] As described herein, there maybe several variations of such a system. In one exemplary variation, the scanning system 130 may include a polygon scanner 132 having multiple reflective faces for continuous high-speed scanning. The polygon scanner 132 may direct laser pulses to illuminate successive columns on the digital mask system 140 as the polygon rotates. As another exemplary variation, the digital mask system 140 may be a system that includes or is a digital micromirror device (DMD) oriented to achieve aIRRA-M05-PCT blazed grating condition, which may provide temporal focusing and enhanced diffraction efficiency. Modulated light from the digital mask system 140 maybe delivered to the objective lens 160 via the projection optics 150, which may include relay lenses and scan lenses configured to image the digital mask pattern onto the patterning plane within the substrate material 170.

[0051] The system 100 may be used with various patterning materials. In some variations, the substrate material 170 may include a photosensitive gel with chromophore dye molecules that locally bind within the substrate material upon multiphoton absorption. In other variations, the substrate material 170 may include materials for radical-initiated polymerization, metal salt reduction, or other multi-photon patterning processes. The system 100 maybe used for fabrication of optical components, microfluidic devices, biological scaffolds, and other three-dimensional structures.

[0052] In some variations, the system may incorporate specialized digital mask configurations using multiple discrete digital mask subsystems for improved throughput. As shown in FIGS. 5A, 5B, 6, and 7, a multi-photon lithography system 100 may include an optical pulse source 110, line-forming optics 120, a scanning system 130, a digital mask system 140 comprising a first DMD 142 and a second DMD 144, a scanning system directing the line-shaped beam to the first DMD 142 during a first time period and to the second DMD 144 during a second time period, projection optics 150, an objective lens 160 focusing light onto a patterning plane within a substrate material 170, and a controller 180. This multiple DMD configuration may improve system throughput by reducing downtime associated with digital mask refresh cycles and / or by increasing the total field of view. For example, the first DMD 142 and second DMD 144 may be tiled to provide an enlarged total field of view, or the scanning system may alternate between DMDs such that one DMD patterns while the other refreshes its pattern, or both.

[0053] FIG. 2 illustrates an exemplary system variation incorporating multiple DMDs and a shared scanner element. In FIG. 2, a femtosecond laser source (optical pulse source 110) provides a pulsed light beam that is split into multiple parallel optical paths. Each path includes dispersion control, laser power / pulse energy control, and beamIRRA-M05-PCT shaping elements (line-forming optics 120). The multiple beam-shaped outputs converge at a shared scanner element (scanning system 130), which distributes the light to multiple scanning optics paths, each leading to a respective DMD (e.g., first DMD 142, second DMD 144 within digital mask system 140). Modulated light from the multiple DMDs is received by relaying and combining optics (projection optics 150), which merge the light into a common optical path. The combined light reflects from a dichroic mirror and is focused by an objective lens (objective lens 160) onto a sample (substrate material 170). An imaging microscope receives light from the dichroic mirror for in-situ monitoring of patterning. This configuration illustrates one approach to incorporating multiple DMDs with a shared scanning element for increased throughput.

[0054] In some variations, the system may incorporate specialized control configurations enabling variable exposure levels within patterned structures. As shown in FIG. 8B, a multi-photon lithography system 100 may include an optical pulse source 110, line-forming optics 120, a scanning system 130, a digital mask system 140, projection optics 150, an objective lens 160 focusing light onto a patterning plane within a substrate material 170, and a controller 180 that varies optical exposure delivered to different voxels within the substrate material 170 by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level. The controller 180 may achieve variable exposure through multiple sweeps at different power levels, through pixel binning configurations on the digital mask system 140, through power modulation, or through combinations of these approaches. This variable exposure capability may enable fabrication of structures with spatially varying material properties, such as gradient-index optical components.

[0055] In some variations, the system may incorporate specialized optical configurations enabling a tilted patterning plane for continuous three-dimensional volume patterning. As shown in FIG. 11, a multi-photon lithography system 100 may include an optical pulse source 110, line-forming optics 120, a scanning system 130, a digital mask system 140, projection optics 150, an objective lens 160 focusing light onto a patterning plane within a substrate material 170, and a controller 180, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrateIRRA-M05-PCT material 170, the tilt angle enabling patterning of a three-dimensional volume within the substrate material 170 via lateral translation of the patterning plane relative to the substrate material. FIG. 11 illustrates an objective lens focusing a laser beam shaped into a DMD shape onto a tilted wafer or substrate. As the wafer is moved both vertically (in the Z direction) and laterally (in the X direction) via a translation stage, patterning occurs along a diagonal path through the substrate material. The purpose of this configuration is to maximize the distance along which printing may occur while minimizing acceleration or deceleration of the translation stage (which occurs only at the edges of the wafer). This tilted patterning plane configuration may enable the system to pattern a three-dimensional volume with thickness greater than the single-voxel axial resolution while scanning continuously in the lateral XY directions, reducing the number of stitching boundaries and thereby increasing throughput and reducing stitching errors.

[0056] In some variations, the system may incorporate specialized line-forming configurations enabling efficient utilization of the digital mask in a blazed grating condition. As shown in FIGS. 4A and 4B, a multi-photon lithography system 100 may include an optical pulse source 110, line-forming optics 120 producing a line-shaped beam that forms a focal line tilted greater than 30 degrees with respect to a scan direction, a scanning system 130, a digital mask system 140 with the focal line aligned with a pixel array axis of the digital mask system 140 for operation in a blazed grating condition, projection optics 150, an objective lens 160 focusing light onto a patterning plane within a substrate material 170, and a controller 180. The tilt angle maybe between 30 and 60 degrees, between 40 and 50 degrees, or substantially 45 degrees (e.g., + / - 2 degree of 45). This configuration may enable utilization of a greater portion of the digital mask area compared to non-tilted configurations.

[0057] In some variations, the system may incorporate active beam shaping configurations enabling dynamic correction of the line-shaped beam profile. As shown in FIG. 9, a multi-photon lithography system 100 may include an optical pulse source 110, line-forming optics 120, a scanning system 130, a digital mask system 140, projection optics 150, an objective lens 160 focusing light onto a patterning plane within a substrate material 170, a controller 180, a spatial light modulator (SLM) in a beamIRRA-M05-PCT path between the optical pulse source no and the digital mask system 140, a sensor measuring a beam profile of the line-shaped beam, and a feedback controller coupling the sensor to the SLM and adjusting the SLM to correct for aberrations during scanning. The feedback controller maybe part of or separate from the controller 180. This active feedback configuration may maintain consistent beam quality during scanning, providing more uniform illumination across the patterning field and compensating for variations that may occur during scanning or due to manufacturing tolerances in digital mask components.

[0058] The optical pulse source 110 functions as a light source generator used for multi-photon lithography. The optical pulse source 110 is positioned at the beginning of an optical path of the system 100 and is configured to generate a pulsed light beam that is directed toward the line-forming optics 120. The optical pulse source 110 maybe a pulsed laser source. The pulsed laser may generate pulses of light having a broad spectral bandwidth relative to continuous wave lasers. The light pulses maybe dispersed and refocused on the substrate material 170 with control over patterning in the axial (Z) direction, where the Z-axis is defined along the optical axis.

[0059] The systems and methods may use various laser wavelengths depending on the application. Different laser wavelengths may have enhanced results for different fabricated devices or substrate material chemistries. In one variation, wavelengths near 1 micron (e.g., 1030 nm, 1064 nm) maybe used. These wavelengths are often available at high powers for relatively low cost and typically have high efficiency with many known two-photon absorption chromophores. However, the relatively large wavelength may limit the minimum feature size due to the wavelength dependence of the diffraction-limited spot size. Thus, these wavelengths maybe suitable for creating coarser, large-volume, lower-resolution structures.

[0060] In another variation, second harmonic generation (SHG) of these lasers may be used to generate high-power femtosecond pulsed green lasers with wavelengths around 515-530 nm. This decrease in wavelength may greatly reduce the diffractionlimited spot size, increasing resolution. However, it may also result in lower patterning efficiency due to reduced two-photon absorption cross sections at this wavelength. Thus,IRRA-M05-PCT these wavelengths may be preferred for creating higher-resolution, lower- volume components.

[0061] In yet another variation, near-infrared (NIR) femtosecond laser wavelengths around 800 nm maybe used, providing a balance between the above extremes. Many high two-photon absorption cross sections have been identified at this wavelength, and the smaller wavelength provides enhanced resolution compared to 1030 nm lasers. In still another variation, third harmonic generation with holmium or thulium lasers may be used to generate wavelengths around 700 nm.

[0062] These different wavelength ranges may be achieved using various laser types. Different gain media such as ThSapphire, Nd:YAG, erbium-doped fibers, and others may be used. Different configurations such as second harmonic generation (SHG) and optical parametric chirped pulse amplification (OPCPA) may be used to change the wavelength of a pump or seed laser.

[0063] The systems and methods may use a single laser system or multiple laser systems. In one variation, a single high-power laser maybe used. In another variation, multiple smaller, synchronized lasers may be combined. The lasers may be synchronized and combined to form a single high-power beam, or they may be offset in time to form a beam with higher average power and higher effective repetition rate, or they may be combined by illuminating and scanning over different areas of the digital mask system 140.

[0064] In some variations, multiple different kinds of laser sources may be used in conjunction. For example, one-photon and two-photon processes maybe used together. This may include a 2+1 photon process, where two-photon absorption creates an excited state that may then absorb additional photons from a pulsed laser to become reactive.

[0065] Typical powers of the optical pulse source 110 may range from single watts to hundreds or thousands of watts. Typical laser pulse widths may range from 10 fs to 1 ps. Repetition rates may range from kHz to MHz.

[0066] As shown in FIG. 15A, in some variations, the optical pulse source no may operate in burst mode, wherein the laser emits multiple pulses very close to each other in short bursts before resetting and firing again in another burst. In burst mode operation, multiple pulses are grouped together within each burst, with a repetition rateIRRA-M05-PCT defined as the time between successive bursts. This burst mode operation may provide another approach for delivering multiple closely-spaced pulses to reduce patterning threshold energy.

[0067] As shown in FIG. 15B, in some variations, the pulse train from the optical pulse source 110 may be shaped using optical pulse shaping techniques. Pulse shaping may be achieved using gratings, virtually imaged phased arrays (VIPAs), and lenses to create pulse trains with different temporal profiles. For example, one pulse shaping option may produce a pulse train with a strong middle pulse and smaller pulses before and after. Another pulse shaping option may produce pulses that build up in strength over the burst. These shaped pulse trains may be tailored to optimize patterning characteristics for specific substrate materials 170 or patterning requirements.

[0068] The system 100 may include one or more optical elements which maybe used in altering light before or after modulation by the digital mask system 140. This may include mirrors, lens arrays, diffraction gratings, optical lenses, filters, and / or other suitable optical elements. The optical elements maybe categorized as line-forming elements positioned before the digital mask system 140 and projection optics positioned after the digital mask system 140. In particular, the optical elements of the system may include line-forming optics 120 used to shape the pulsed light beam into a line-shaped beam prior to the digital mask system 140, projection optics 150 used to receive modulated light from the digital mask system 140 and project the modulated light toward a patterning plane, and an objective lens 160 used to focus the light onto the patterning plane within the substrate material 170.

[0069] The line-forming optics 120, which function to receive the pulsed light beam and produce a line-shaped beam having an elongated cross-section, may include various optical elements for shaping the beam. The line-forming optics 120 are positioned in an optical path between the optical pulse source 110 and the scanning system 130. The lineforming optics 120 are configured to receive the pulsed light beam from the optical pulse source 110, and the resulting line-shaped beam is directed toward the scanning system 130.

[0070] In one variation, the pulsed light from the optical pulse source no maybe shaped into a single focused line that is directed at the digital mask system 140 and / orIRRA-M05-PCT alternatively a scanning system. This may be accomplished using a cylindrical lens or other beam-shaping optics.

[0071] In some variations, the optical form may be more complex than a single focused line. This may be particularly useful when the repetition rate of the pulsed laser is too low to achieve one pulse per line while scanning over the entire digital mask. For example, if the scan area of a digital mask is 1,000 x 1,000 pixels and the digital mask refresh rate is 15 kHz, achieving one pulse per line for a single scanned line may require a repetition rate of 15 MHz. Many high-power lasers may not reach these high repetition rates, instead providing 2-5 MHz. With such lasers, the system may be configured to focus the light beam on multiple parallel lines, and then scan them over a smaller portion of the digital mask.

[0072] Multiple parallel lines or other patterns may be accomplished by a cylindrical lens array, a diffractive optical element (DOE), or other optics. The pattern may include parallel lines, an array of spots, curved lines, or other shapes. As shown in FIG. 10, passive beam-shaping elements such as Wollaston prisms or Fresnel bi-prisms may be used to create multiple beams via polarization splitting. FIG. 10 illustrates the concept of making two beams that are then shaped into lines by splitting the beam into two polarizations. An incoming laser beam enters a Wollaston prism, which splits the beam into two separate beams based on polarization (e.g., s-polarization and p-polarization). The two beams pass through a Fresnel bi-prism and then through optics that shape each beam into a line. The two line-shaped beams follow separate paths and are directed to a polygon scanner, which scans the beams across a DMD. This passive shaping approach may provide an example of beam shaping without active feedback control.

[0073] The projection optics 150, which function to receive modulated light from the digital mask system 140 and project the modulated light toward a patterning plane, may include relay lenses, scan lenses, and / or other optical elements arranged to image the digital mask pattern onto the patterning plane within the substrate material 170. The projection optics 150 are positioned in an optical path between the digital mask system 140 and the objective lens 160.

[0074] The objective lens 160 functions to receive light from the projection optics 150 and focus the light onto the patterning plane within the substrate material 170. TheIRRA-M05-PCT objective lens 160 is positioned in an optical path between the projection optics 150 and the substrate material 170. The objective lens 160 maybe the last optical element in the optical path that forms an image of the digital mask onto the substrate material, allowing the digital mask to act as an amplitude mask. The objective lens 160 may have a high numerical aperture (NA) to provide high spatial resolution. The NA may range from 0.3 to 0.9 for various applications, or above 0.9 for applications requiring higher resolution. For NA above approximately 0.9, the objective lens 160 maybe immersed in an immersion oil or other index-matching medium.

[0075] The objective lens 160 may have a flat field that is undistorted and free of optical aberrations. Aberrations occur when the light beam's wavefront deviates from ideal, causing images to blur or distort. The objective lens 160 may be composed of multiple lens groups to correct for various aberrations. In some variations, the objective lens 160 may include arrays of lens systems where each lens has two or more surfaces, diffractive elements, or gradient-index (GRIN) elements.

[0076] The projection optics 150 may include scan lenses designed to minimize F-theta error. F-theta error occurs when scan speed is not linear, resulting in non-uniform spacing of laser pulses across the digital mask. Scan lenses of various effective focal lengths maybe used to minimize F-theta error.

[0077] In some variations, the system may include a partially silvered mirror in an imaging path. The partially silvered mirror may be positioned between the projection optics 150 and the objective lens 160, or alternatively between the digital mask system 140 and the projection optics 150. The partially silvered mirror may provide angleindependent operation compared to a dichroic mirror. Dichroic mirrors exhibit wavelength-dependent reflectivity that varies with angle of incidence, which may cause issues in configurations where light arrives at a range of angles. A partially silvered mirror may reflect and transmit a fixed fraction of light independent of wavelength and angle, which maybe useful for in-situ imaging configurations where angle-dependent behavior of dichroic mirrors may cause imaging artifacts or inconsistent patterning.

[0078] The scanning system 130, which functions to receive the line-shaped beam and direct the line-shaped beam across a scan range, may include various scanning mechanisms for directing the beam across the digital mask system 140. The scanningIRRA-M05-PCT system 130 may comprise a single scanning element or a configured set of multiple scanning elements. When comprising multiple scanning elements, the scanning system 130 may direct the line-shaped beam to different portions of the digital mask system 140 or to different digital mask elements within the digital mask system 140. The scanning system 130 is positioned in an optical path between the line-forming optics 120 and the digital mask system 140. The scanning system 130 may comprise a reflective or optically redirecting component that is rotatable or otherwise actuatable to change an output direction of the scanning system 130. As the reflective or optically redirecting component is rotated or actuated, the output direction changes, thereby sweeping the line-shaped beam across the scan range toward the digital mask system 140. The scan range corresponds to a region of the digital mask system 140 across which the lineshaped beam moves during a sweep. As the scanning system 130 directs the beam through the scan range, the line-shaped beam sequentially illuminates different portions of the digital mask system 140, enabling the digital mask system 140 to modulate successive segments of the beam according to the spatial pattern.

[0079] In one variation, the scanning system 130 may include a galvanometer scanner (galvo) providing angular deflection of the beam. Galvanometer scanners may use an oscillating mirror driven by a galvanometer motor to scan the beam back and forth across the digital mask system 140. Galvanometer scanners may provide precise control over scan position and may be suitable for applications requiring variable scan patterns or bidirectional scanning.

[0080] In another variation, the scanning system 130 may include a polygon scanner 132 having multiple reflective faces for continuous high-speed scanning. As described below, the polygon scanner 132 may provide advantages for high-throughput applications where continuous unidirectional scanning at high speeds is desired.

[0081] As shown in FIG. 3, in some variations the scanning system 130 may comprise a polygon scanner 132 having multiple reflective faces. FIG. 3 illustrates the overall concept of line-scan patterning. In this exemplary variation, a DMD is rotated by 45 degrees to achieve the blazed condition, which provides enhanced temporal focusing and diffraction efficiency. The pulsed laser is shaped into a line and then scanned across the surface of the DMD by a polygon scanner mirror. As the polygon scanner rotates,IRRA-M05-PCT laser pulses illuminate successive columns on the DMD over time, as indicated by the time axis in FIG. 3. The illuminated columns on the DMD are mapped via projection optics to an objective lens field of view, which in turn is mapped to a sample plane. The resulting diffracted light is delivered to the objective lens via the projection optics. The polygon scanner 132 may include a rotating polygon with multiple reflective faces (e.g., 4, 6, 8, or more faces) that rotate continuously, directing the line-shaped beam across the digital mask system 140 as each face passes through the beam path. As the polygon rotates, each reflective face sweeps the line-shaped beam across the digital mask system 140, and then the next face enters the beam path to begin another sweep. The polygon scanner 132 maybe customized with different numbers of faces and different rotation speeds to achieve a desired scanning rate. For example, a polygon with more faces may provide more sweeps per rotation but with a smaller angular range per face, while a polygon with fewer faces may provide fewer sweeps per rotation but with a larger angular range per face. The mirrors may be angled to direct light upwards, downwards, or generally out of the plane of the polygon, which may be useful for directing light to digital mask systems 140 positioned at various orientations.

[0082] In some variations, the system may comprise a plurality of polygon scanners arranged in parallel or in series. In a parallel arrangement, multiple polygon scanners may each receive a portion of the line-shaped beam (e.g., via beam splitting) and direct their respective portions to different areas of the digital mask system 140 or to different digital mask subsystems. In a series arrangement, the line-shaped beam may pass through multiple polygon scanners sequentially, with each polygon scanner contributing to the overall scanning pattern. The plurality of polygon scanners may deflect light to different DMDs within the digital mask system 140, enabling configurations where multiple DMDs are patterned simultaneously or in rapid succession.

[0083] In some variations, the plurality of polygon scanners may be operated in-phase or out-of-phase to reduce dead time at polygon face transitions. In-phase operation refers to multiple polygon scanners rotating such that their reflective faces reach scanning positions at the same time. Out-of-phase operation refers to multiple polygon scanners rotating with offset timing such that their reflective faces reach scanning positions at different times. Out-of-phase operation may reduce dead time atIRRA-M05-PCT polygon face transitions by ensuring that when one polygon scanner reaches the edge of a facet where scanning is suboptimal (e.g., at a corner or edge transition between faces), another polygon scanner is positioned in a good scanning orientation to continue scanning. This out-of-phase operation may maintain continuous patterning and reduce or eliminate gaps in exposure that might otherwise occur during face transitions. When combined with multiple DMDs, the coordinated timing may also avoid dead time as the digital mask pattern is changed between frames. For example, a first polygon scanner may scan across a first DMD while the first DMD has its pattern set, while at the same time a second polygon scanner is oriented away from a second DMD, giving the second DMD time to refresh its pattern. The second polygon scanner may then scan across the second DMD while the first DMD refreshes.

[0084] The digital mask system 140, which functions to receive the line-shaped beam from the scanning system 130 and modulate the line-shaped beam according to a spatial pattern, comprises an array of individually addressable elements. More generally, the digital mask system 140 may serve as a light manipulation system that augments or patterns light. The digital mask system 140 is positioned in an optical path between the scanning system 130 and the projection optics 150. As the scanning system 130 sweeps the line-shaped beam across the digital mask system 140, the individually addressable elements modulate the beam by selectively transmitting, reflecting, or blocking portions of the beam according to the spatial pattern. The modulated light from the digital mask system 140 is directed toward the projection optics 150.

[0085] In some variations, the individually addressable elements may be micromirrors that can be tilted between an on state and an off state. In such variations, the digital mask system 140 may include one or more digital micromirror devices (DMDs). In other variations, the individually addressable elements may be liquid crystal elements, piston-type micromirrors (PLMs), active phase modulators, or other types of addressable optical elements.

[0086] Typical commercially available digital micromirror devices (DMDs) have a digitally controlled mirror tilt that is rotated 45 degrees with respect to the orthogonal axes of the micromirror array. When the DMD is used as a diffraction grating in a blazed grating condition, the incoming and outgoing optical axes are coplanar with the mirrorIRRA-M05-PCT tilt axis. When a line is scanned across the DMD in this plane, the system may utilize less than 50% of the DMD pixels, or may significantly overscan the DMD and lose optical power.

[0087] In some variations, the system and methods may make use of a tilted line scan over a DMD to mitigate such issues. FIGS. 4A and 4B illustrate different orientations of the DMD to achieve a blazed condition for optimal temporal focusing. Temporal focusing maybe achieved for multiple orientations of the DMD. As shown in FIGS.4A and 4B, the line-shaped beam may form a focal line tilted greater than 30 degrees with respect to a scan direction, with the focal line aligned with a pixel array axis of the digital mask for operation in a blazed grating condition. FIG. 4A illustrates a first option in which the DMD (e.g., a DMD having dimensions of 4096 pixels by 2176 pixels) is angled 45 degrees, with a useable FOV region within the rotated DMD area. FIG. 4B illustrates a second option in which the whole DMD chip is used, with the optical system optimized for the correct blazed condition on the correct diffraction order. The tilt angle may be between 30 and 60 degrees, between 40 and 50 degrees, or substantially 45 degrees. Tilting the focal line to align with the pixel array axis may enable the system to utilize a greater portion of the DMD pixels compared to non-tilted configurations. This may be achieved by rotating a cylindrical lens element used to focus the optical beam onto a line on the DMD, thereby aligning the line-shaped beam to a row or array of pixels of the DMD.

[0088] To further enhance the tilted line configuration, the system may include compensation elements that maintain uniform focus along the tilted focal line. In one variation, the system may comprise a phase plate compensating for focal distance variation along the tilted focal line. The phase plate may introduce an optical path length difference along the line that ensures uniform focusing across the full length of the focal line.

[0089] In another variation, the line-forming optics 120 may comprise a cylindrical lens element having varying focal length along the focal line. The varying focal length may compensate for the focal distance variation introduced by the tilted lineconfiguration.IRRA-M05-PCT

[0090] In some variations, the digital mask system 140 may include multiple digital mask elements. Using multiple digital mask elements may enable patterning of larger areas or patterning at higher rates compared to single-element configurations. The multiple digital mask elements maybe of the same type (e.g., multiple DMDs) or of different types.

[0091] In some variations, as shown in FIGS.5A, 5B, 6, and 7, the digital mask system 140 may comprise a first DMD 142 and a second DMD 144. The first DMD 142 and the second DMD 144 each comprise an array of individually addressable mirror elements. The scanning system 130 may direct the line-shaped beam across the first DMD 142 and the second DMD 144. Using more than one DMD may enable patterning of larger areas or patterning at higher rates compared to single-DMD configurations.

[0092] In some variations, the first DMD 142 and the second DMD 144 may be tiled in an image plane such that their respective fields of view are adjacent, providing an enlarged total field of view. Tiling multiple DMDs may provide a greater degree of parallelization, enabling simultaneous patterning across a larger area than achievable with a single DMD.

[0093] In some variations, the scanning system may alternate between directing light to the first DMD 142 and directing light to the second DMD 144, such that one DMD patterns while the other DMD refreshes its pattern. DMDs typically have a refresh time when the pattern is being reset, during which they cannot be used for patterning. By switching between two or more DMDs, the system may reduce this downtime and maintain a higher duty cycle for patterning. As described above with respect to the polygon scanner variation, multiple polygon scanners operated out-of-phase may similarly coordinate timing between multiple DMDs, with one polygon scanner scanning across a first DMD while the other polygon scanner is oriented away from a second DMD, giving the second DMD time to refresh.

[0094] In some variations, the system may comprise a plurality of DMD sets, wherein each DMD set comprises multiple tiled DMDs, and wherein the scanning system switches between DMD sets. This combination of tiling and switching may provide both an enlarged field of view (from tiling) and reduced refresh downtime (from switching between sets).IRRA-M05-PCT

[0095] When using multiple DMDs, the modulated light from each DMD may be combined or merged into a common optical path for delivery to the projection optics 150 and focusing onto the substrate material 170. Various optical configurations maybe used for combining light from multiple DMDs.

[0096] As shown in FIGS. 5A and 5B, in some variations, the system may comprise a knife-edge mirror combining modulated light from the first DMD 142 and the second DMD 144 into a common optical path. FIG. 5A illustrates a three-dimensional perspective view in which modulated light from DMD 1 and DMD 2 is directed toward a knife-edge mirror, and the combined light passes through a relay lens and tube lens, reflects from a dichroic mirror, and enters an objective lens. FIG. 5B illustrates a schematic top-down view of the knife-edge mirror combining configuration, with beams from DMD 1 and DMD 2 arriving from different directions and merging into a common optical path. FIG. 5B also shows an imaging microscope positioned to receive light from the dichroic mirror for in-situ monitoring of printing.

[0097] As shown in FIG. 6, in some variations, the system may comprise a concave mirror receiving modulated light from the first DMD 142 and the second DMD 144 at different angles and directing the modulated light along a common optical path. FIG. 6 illustrates DMD 1 and DMD 2 each receiving light from separate scanning optics and outputting modulated light toward a concave mirror. The concave mirror combines the beams from both DMDs and directs the combined light through relay lenses to a dichroic mirror and objective lens. An imaging microscope is positioned to receive light from the dichroic mirror for in-situ monitoring.

[0098] As shown in FIG. 7, in some variations, the scanning system may comprise a plurality of electro-optic modulators (EOMs), a plurality of polarization beam splitters (PBSs), and a combining polarization beam splitter. FIG. 7 illustrates a laser source with two outputs (e.g., 35 fs pulses at 8 MHz) providing light to two parallel optical paths, each including an EOM and PBS. The EOMs switch the polarization of the beams in time, and the PBSs redirect the beams based on polarization state. Light of s-polarization is directed toward a first DMD block (DMD Block 1), and light of p-polarization is directed toward a second DMD block (DMD Block 2). The modulated light from both DMD blocks is combined at a combining PBS and directed through aIRRA-M05-PCT dichroic mirror to an objective lens for focusing onto a sample. An imaging and metrology subsystem receives light from the dichroic for in-situ monitoring. The EOMs switch polarization states in a time-multiplexed fashion such that the laser beams alternate between one block of DMDs and the other, enabling efficient usage of laser power by directing all available light to whichever DMD block is currently active while the other refreshes its pattern.

[0099] In some variations, the system may comprise at least a third DMD, wherein the scanning system directs light sequentially to each of the first DMD 142, the second DMD 144, and the third DMD. Using three or more DMDs may further reduce refresh downtime by providing additional DMDs that can be refreshed while others are patterning.

[0100] In some variations, the controller 180 may comprise a field-programmable gate array (FPGA) streaming pattern data to the first DMD 142 and the second DMD 144 at a sustained refresh rate of at least 10 kHz. High-throughput multi-photon lithography may require digital mask refresh rates and sustained data throughput that approach or exceed typical operating parameters of commercial DMDs. The FPGA may enable the controller 180 to maintain sustained high-speed pattern streaming to support continuous patterning operations.

[0101] The substrate material 170, which functions as the medium that is patterned via multi-photon absorption, is positioned to receive focused light from the objective lens 160. The substrate material 170 contains a patterning plane at which the objective lens 160 focuses the modulated light. The substrate material 170 is a photosensitive medium that is altered via multi -photon absorption when exposed to focused light at the patterning plane. In some variations, the substrate material 170 may be a gel or other suitable material.

[0102] In some variations, the substrate material 170 may comprise chromophore dye molecules that locally bind within the substrate material 170 upon multi-photon absorption. In other variations, the substrate material 170 may comprise radical initiator molecules that undergo two-photon absorption and radical generation to initiate polymerization. In yet other variations, the substrate material 170 may comprise metal salts in solution that are reduced via two-photon absorption to pattern metals.IRRA-M05-PCT The substrate material 170 may also comprise nanoclusters as chromophores that may be directly patterned or used to catalyze subsequent reactions. These different patterning mechanisms may be used individually or in combination, either in parallel (e.g., using different laser wavelengths or power levels to access different absorption mechanisms) or serially (e.g., by exchanging patterning solutions while maintaining alignment).

[0103] The controller 180, which functions to coordinate operation of the scanning system 130 and the digital mask system 140 to pattern the substrate material 170 via multi-photon absorption, is operatively coupled to the scanning system 130, the digital mask system 140, and in some variations the stage 190 and / or optical pulse source 110. The controller 180 may include hardware, firmware, and / or software components configured to synchronize timing between the scanning system 130 and the digital mask system 140, including triggering, timing, and delays.

[0104] As shown in FIG. 8A, in some variations, the controller 180 may comprise or integrate with a field-programmable gate array (FPGA) configured to stream pattern data to the digital mask system 140. FIG. 8A illustrates the data flow for high-speed pattern streaming: a controlling PC streams frames to an FPGA controller at 12 kHz, the FPGA controller processes the pattern data and streams frames to a DMD controller at 12 kHz, and the DMD controller drives the DMD chip. This FPGA-based architecture may achieve full printing throughput by maintaining sustained high-speed pattern streaming. In one variation, the controller 180 may stream pattern data at a sustained refresh rate of at least 10 kHz. Lithography volumes maybe quite large with very small feature sizes, resulting in memory requirements of hundreds of gigabytes to terabytes. The controller 180 may include specialized firmware to efficiently load sequential patterns from memory onto the digital mask system 140 with correct timing.

[0105] In some variations, the controller 180 may comprise a lookup table correlating exposure parameters to resulting exposure levels in the substrate material 170. The lookup table maybe populated empirically or theoretically to enable settings of the system 100 to be selectively used for different desired effects. Such aspects may include laser powers needed to achieve different exposure levels, digital mask pixel patterns to achieve variable exposure, feature-size dependence of the resolution (e.g.,IRRA-M05-PCT changing patterned thickness as a function of the size and shape of adjacent on pixels in the digital mask), and effects of pixel overlap on resulting material shape and properties.

[0106] The controller 180 may also include software configured to convert a three-dimensional design into a series of digital mask patterns. Such software may take a design consisting of material properties in three-dimensional space and convert it into a series of two-dimensional digital mask patterns combined with information on laser power and stage movements for each patterning pass.

[0107] In some variations, the controller 180 may include specialized software and / or user interfaces configured to assist a user in creating a design. The design software maybe configured for defining arbitrary three-dimensional geometries where every point has spatial coordinates and material property information (e.g., refractive index). This maybe accomplished using CAD tools (e.g., drawing and extruding two-dimensional shapes, three-dimensional shapes such as spheres, one-dimensional, two-dimensional, and / or three-dimensional arrays of objects, importing STL files) and / or by directly importing data from external software (e.g., Python or MATLAB matrices). In some variations, the design software maybe configured so that structures maybe parametrically defined. For example, software may define a lens with a focal length parameter that, when changed, directly modifies the spatial coordinates and material property values of the lens as well as relationships to other components. The design software may also enable direct visualization of material properties in three dimensions and may enable output of patterning data based on user-defined parameters such as spatial resolution. The software may include options for modifications and overlay functions in the output, such as overlays to account for voxel proximity effects or stitching correction. The software may also support different ways of slicing a patterning volume into regions, and may compress design or patterning files to reduce storage requirements.

[0108] The controller 180 may comprise one or more of a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a microcontroller unit (MCU), a programmable logic controller (PLC), software executed on a general-purpose computing unit (e.g., CPU, GPU, or TPU) with or without a real-time operating system (RTOS) exhibiting deterministic or quasi-deterministic timing behavior, analog controlIRRA-M05-PCT circuitry for feedback loops, or a digital acquisition device (DAQ). In one variation, the controller 180 may comprise a software-based computational framework operating on a general-purpose computer in a non-real-time environment, which supervises and coordinates a deterministic hardware subsystem implemented on an FPGA.

[0109] As shown in FIG. 18, the controller 180 may receive various input signals, process them using one or more compute resources, and generate various output signals to coordinate subsystem operation. FIG. 18 illustrates various input options, control system compute resources, and output options that may be employed in different variations of the system 100. A given implementation may employ any subset or combination of the illustrated elements depending on system architecture and application requirements.

[0110] The controller 180 may receive input signals (which may be analog or digital) from various sources. In some variations, the controller 180 may receive a master clock signal from a standalone clock source, which may serve as a primary synchronization reference for the system 100 or as a supplemental clock reference. In some variations, the controller 180 may receive laser pulse-train signals from one or more photodiodes positioned to detect pulse timing from the optical pulse source 110, which may include multiple laser outputs. In some variations, the controller 180 may receive a scanner monitoring signal generated by a monitoring laser and photodetector arrangement configured to detect a reference point on the scanning system 130 (e.g., start-of-scan, end-of-scan, or other phase reference), providing scanner position or phase information. In some variations, the controller 180 may receive active alignment monitoring signals indicative of beam alignment status. In some variations, the controller 180 may receive stage feedback signals including position, velocity, and / or acceleration information from encoders or other sensors associated with the stage 190. In some variations, the controller 180 may receive signals from quadrant detectors, wavefront sensors, and / or cameras configured for in-situ monitoring of the patterning process.

[0111] The controller 180 may include various compute resources organized in a hierarchical architecture. A digital controller (which maybe implemented as an ASIC, FPGA, MCU, or software executing on a CPU or GPU with or without an RTOS) mayIRRA-M05-PCT serve as a central processing element that receives input signals and generates output signals. The digital controller may execute fast inner control loops requiring deterministic timing. A supervisory control system (which may be implemented as software executing on a general-purpose computing unit) may coordinate with the digital controller and may perform functions including streaming frames to a digital mask buffer and loading modifications to the digital controller. The supervisory control system may execute slow supervisory loops including recipe execution, dose optimization, and in-si tu adaptation. The controller 180 may further include a bulk storage array for storing pattern data (which may be hundreds of gigabytes to terabytes in size) and a storage control system for managing data flow to the supervisory control system and digital mask controllers. The controller 180 may further include one or more digital mask controllers dedicated to streaming pattern data to the digital mask system 140.

[0112] The controller 180 may generate output signals (which may be analog or digital) to various subsystems. In some variations, the controller 180 may generate scanner control signals for controlling scanner position, velocity, and / or phase. In some variations, the controller 180 may generate AOM control signals for acousto-optic modulator gating and / or amplitude control. In some variations, the controller 180 may generate EOM control signals for electro-optic modulator control including polarization switching, pulse gating, and / or amplitude control. In some variations, the controller 180 may generate DMD synchronization signals for coordinating digital mask pattern updates with beam position and laser timing. In some variations, the controller 180 may generate digital mask trigger, clock, and / or phase signals to digital mask controllers to ensure DMD pattern refresh is synchronized with system timing. In some variations, the controller 180 may generate control signals to digital mask active alignment stages for fine-tuning DMD position for registration. In some variations, the controller 180 may generate control signals to active alignment mirror mounts for beam steering and alignment correction. In some variations, the controller 180 may generate stage controller commands including position, velocity, and / or acceleration commands for controlling the stage 190.IRRA-M05-PCT

[0113] In many variations, the system 100 operates under a unified timing architecture in which a primary clock signal governs synchronization across subsystems. The controller 180 may comprise a clock input configured as a synchronization source used in determining control outputs to one or more of the digital mask system 140, the stage 190, the optical pulse source 110, or the scanning system 130. Control signals to the scanning system 130, the digital mask system 140, and other system elements may be synchronized to the clock input. The clock input may receive a timing signal generated as a standalone reference and distributed throughout the system, with other components synchronized to it (e.g., via one or more phase-locked loops (PLLs) or other synchronization mechanisms). Alternatively, the timing signal may be derived from one of the system subsystems or components, such as the laser pulse repetition rate, the stage 190, the scanning system 130, or the digital mask system 140 timing.

[0114] In such configurations, one or more control loops (e.g., PLLs or other synchronization mechanisms) maybe used to align the timing, phase, and / or frequency of other subsystems to the selected timing signal. This may ensure coordinated operation between laser emission, beam positioning, and / or modulation. In some variations, synchronization may be established based on multiple signals rather than a single reference. For example, two or more timing sources (e.g., laser pulse timing and scanner position) may be jointly considered to determine system timing, enabling hybrid or adaptive synchronization schemes. Such approaches may improve robustness to drift, latency, or dynamic variations in system behavior.

[0115] In some variations, the timing signal may be derived from the scanning system 130. Scanner position, velocity, acceleration, and / or error maybe determined by one or more of: a synchronization light source and photodetector positioned to detect a reference point on the scanning system 130 (e.g., start-of-scan (SOS), end-of-scan (EOS), or other phase offset), an interferometric position sensor, a time-of-flight position sensor, an optical encoder with rotary encoder disk, back-EMF sensing, capacitive sensing, Hall effect arrays or magnetoresistive sensors, and / or an inductive position sensor. The photodetector may generate the timing signal received by the clock input, and may comprise one or more regular photodiodes, lateral-effect photodiodes, a quadrant detector, a one-dimensional linear array of photodiodes, or a two-dimensionalIRRA-M05-PCT array of photodiodes, which may provide position, velocity, and / or acceleration data in addition to timing triggers. Other monitoring systems of the scanner and / or other clock sources may alternatively be used.

[0116] In some variations, the timing signal may be derived from the digital mask system 140. The digital mask system 140 may send trigger signals, and the controller 180 may apply phase delays to other components (e.g., the optical pulse source 110, the scanning system 130, and / or the stage 190) to synchronize them to the digital mask timing. In some variations, the timing signal may be derived from the optical pulse source 110. The controller 180 may add or subtract phase delays to both the optical pulse source 110 and the scanning system 130 to synchronize them, and then trigger the digital mask system 140 based on that synchronized timing. Once these subsystems are synchronized, stage motion may commence with timing that is primarily pre-calculated, with optional small in-process dynamically adjusted delays or shifts to ensure the acceleration and position of the stage 190 coincides with the optical pulses.

[0117] In variations employing multiple scanners (e.g., a plurality of polygon scanners), the controller 180 may include a main control loop configured to phase lock all scanners before commencing synchronized operation. Once the multiple scanners are phase locked, the remaining subsystems may be synchronized based on the phase-locked scanner timing.

[0118] The controller 180 may be configured to receive and generate a variety of input and output signals. Analog inputs may be decoded using a digitizer and analog outputs may be generated using an arbitrary waveform generator, which may be integrated in a digital acquisition device. Inputs may include but are not limited to laser timing signals, laser power measurements, pulse shape and pulse width information, optical power feedback, scanner speed error, scanner detection signals, scanner position or location, stage speed error, stage velocity, stage position, stage acceleration, and / or in-situ monitoring imaging data (including amplitude or phase, point, one-dimensional, two-dimensional, or three-dimensional mapping data). Outputs may include scanner speed control signals, scanner phase control signals, motorized mirror mount control signals, acousto-optic modulator (AOM) gating or amplitude signals, electro-optic modulator (EOM) gating or amplitude signals, digital mask synchronization signals,IRRA-M05-PCT phase controller signals, stage acceleration commands, and / or stage position commands.

[0119] The controller 180 may be configured to execute one or more control loops to coordinate subsystem operation. A given implementation may employ any one of these control loops, or any combination thereof, depending on system architecture and application requirements.

[0120] In some variations, the controller 180 may execute a laser pulse timing synchronization loop configured to synchronize laser pulse emission with the instantaneous spatial position of the beam. The laser pulse timing synchronization loop may receive inputs including laser timing reference, scanner position and / or phase, stage position and velocity, digital mask synchronization signals, and / or line-start or pixel-start triggers. The laser pulse timing synchronization loop may generate outputs including AOM and / or EOM gating signals, laser trigger or burst trigger signals, and / or timing or phase offset corrections. The control objectives may include emitting pulses at intended spatial coordinates, maintaining constant spatial pulse spacing, and / or compensating for latency and jitter.

[0121] In some variations, the controller 180 may execute a pulse-to-position synchronization loop configured to convert spatial exposure requirements into pulse timing based on real-time motion. The pulse-to-position synchronization loop may receive inputs including scanner position, stage position, scanner speed error, stage speed error, and / or commanded pulse pitch or line density. The pulse-to-position synchronization loop may generate outputs including position-based trigger signals, resampled timing clock, AOM or EOM gating patterns, and / or scanner phase trim. The control objectives may include maintaining constant pulses-per-unit -length or energy-per-unit-length, and / or compensating for velocity variations.

[0122] In some variations, the controller 180 may execute a laser power regulation loop configured to stabilize optical power delivered to the substrate material 170. The laser power regulation loop may receive inputs including measured laser power, commanded power setpoint, pulse repetition mode and width, and / or in-situ monitoring signals. The laser power regulation loop may generate outputs including AOM drive amplitude, EOM control signals, and / or laser power commands. The controlIRRA-M05-PCT objectives may include rejecting source drift, maintaining stable average and / or peak power, and / or compensating for scan conditions.

[0123] In some variations, the controller 180 may execute a fluence or dose-per-unit-length regulation loop configured to maintain consistent deposited energy along a scan. The fluence regulation loop may receive inputs including laser power, scan velocity, spot or line dimensions, pulse spacing, and / or in-situ monitoring signals. The fluence regulation loop may generate outputs including laser power adjustments, gating duty cycle modifications, and / or scan speed corrections. The control objectives may include maintaining target fluence despite motion variations.

[0124] In some variations, the controller 180 may execute a scanner position control loop configured to ensure the scan trajectory matches a commanded path. The scanner position control loop may receive inputs including scanner position feedback, scanner detection signals, and / or commanded trajectory. The scanner position control loop may generate outputs including scanner drive commands and / or phase corrections. The control objectives may include minimizing tracking error and / or maintaining spatial accuracy.

[0125] In some variations, the controller 180 may execute a scanner velocity control loop configured to regulate instantaneous scan speed. The scanner velocity control loop may receive inputs including scanner speed feedback and / or commanded velocity profile. The scanner velocity control loop may generate outputs including scanner drive commands and / or phase compensation signals. The control objectives may include maintaining constant scan velocity during exposure.

[0126] In some variations, the controller 180 may execute a scanner phase synchronization loop configured to align scanner motion with laser timing and digital mask signals. The scanner phase synchronization loop may receive inputs including scanner position, laser timing, pixel or line clock, and / or digital mask synchronization signals. The scanner phase synchronization loop may generate outputs including scanner phase control signals, trigger phase offsets, and / or gating alignment signals. The control objectives may include ensuring spatial-temporal alignment of exposure.

[0127] In some variations, the controller 180 may execute a stage position control loop configured to control translation stage position for large-area processing. The stageIRRA-M05-PCT position control loop may receive inputs including stage position feedback, commanded position, and / or alignment references. The stage position control loop may generate outputs including stage motor commands and / or feedforward terms. The control objectives may include maintaining positioning accuracy and stitching consistency.

[0128] In some variations, the controller 180 may execute a stage velocity control loop configured to maintain stage speed during coordinated scanning. The stage velocity control loop may receive inputs including stage speed, speed error, and / or commanded feed rate. The stage velocity control loop may generate outputs including velocity or acceleration commands. The control objectives may include synchronizing stage motion with scanning.

[0129] In some variations, the controller 180 may execute a stage acceleration and jerk control loop configured to ensure smooth motion profiles. The stage acceleration and jerk control loop may receive inputs including stage position, velocity, acceleration, and / or motion profile. The stage acceleration and jerk control loop may generate outputs including acceleration and jerk-limited commands. The control objectives may include reducing vibration and transient positioning error.

[0130] In some variations, the controller 180 may execute a stage-scanner synchronization loop configured to coordinate scanner motion with stage motion. The stage-scanner synchronization loop may receive inputs including scanner position and velocity, stage position and velocity, and / or process state. The stage-scanner synchronization loop may generate outputs including stage feed commands, scanner offsets, and / or stitch corrections. The control objectives may include maintaining continuous effective scan field and minimizing stitching artifacts.

[0131] In some variations, the controller 180 may execute a beam alignment and steering loop configured to maintain optical alignment of the beam and spatiotemporal focus. The beam alignment and steering loop may receive inputs including beam diagnostics, in-situ monitoring signals, and / or mirror mount position. The beam alignment and steering loop may generate outputs including motorized mirror mount control signals. The control objectives may include compensating drift and maintaining beam alignment.IRRA-M05-PCT

[0132] In some variations, the controller 180 may execute a digital mask alignment and stitching loop configured to align digital exposure patterns with physical scan and ensure seamless stitching. The digital mask alignment and stitching loop may receive inputs including digital mask data, scanner position and phase, stage position and velocity, fiducial or registration signals, and / or field transition signals. The digital mask alignment and stitching loop may generate outputs including mask synchronization signals, timing or phase offsets, and / or stitch correction parameters. The control objectives may include maintaining alignment between the digital mask and beam position, and / or ensuring continuity across scan regions.

[0133] In some variations, the controller 180 may execute a pulse shape and width control loop configured to regulate temporal pulse characteristics. The pulse shape and width control loop may receive inputs including pulse shape and width measurements, laser timing, and / or process feedback. The pulse shape and width control loop may generate outputs including pulse shaping commands, modulator control signals, and / or dispersion or compression settings. The control objectives may include maintaining desired temporal pulse profile.

[0134] In some variations, the controller 180 may execute a spatiotemporal focus (STF) optimization loop configured to maintain optimal spatiotemporal recompression at the substrate material 170. The STF optimization loop may receive inputs including in-situ monitoring signals, beam diagnostics, and / or pulse characteristics. The STF optimization loop may generate outputs including dispersion compensation adjustments, alignment adjustments, and / or laser parameter tuning. The control objectives may include maximizing energy localization at the focal point.

[0135] In some variations, the controller 180 may execute an in-situ process feedback loop configured to adapt processing based on real-time material response. The in-situ process feedback loop may receive inputs including optical, acoustic, thermal, or imaging signals, and / or system state. The in-situ process feedback loop may generate outputs including power, timing, or speed adjustments, and / or fault signals. The control objectives may include compensating material variability and detecting process deviations.IRRA-M05-PCT

[0136] In some variations, the controller 180 may execute a feature registration and overlay control loop configured to align features across scans or layers. The feature registration and overlay control loop may receive inputs including fiducial measurements, and / or stage and scanner position. The feature registration and overlay control loop may generate outputs including position offsets and / or mask phase corrections. The control objectives may include maintaining overlay accuracy.

[0137] In some variations, the controller 180 may execute a safety, fault, and exposure interlock loop configured to ensure safe operation and prevent unintended exposure. The safety, fault, and exposure interlock loop may receive inputs including system readiness signals, interlocks, and / or fault conditions. The safety, fault, and exposure interlock loop may generate outputs including laser inhibit or shutter commands, motion stop commands, and / or fault latch signals. The control objectives may include transitioning the system to a safe state under fault conditions.

[0138] In some variations, the controller 180 may implement hierarchical control loop organization. Fast inner loops maybe implemented on FPGA, ASIC, analog circuitry, deterministic MCU, PLC, or RTOS and may handle laser pulse timing lock, pulse-to-position synchronization, scanner servo and phase loops, AOM or EOM gating, safety interlocks, mirror mount stabilization and laser beam correction using motorized mirrors, stage pathing, position, velocity, and acceleration control, and / or stage-to-scanner synchronization. Slow supervisory loops may be implemented on CPU or GPU software and may handle recipe execution, dose optimization, in-situ adaptation, feature and fiducial registration, and / or spatiotemporal focus optimization and calibration. Non-real-time supervisory software may manage recipes while deterministic hardware handles precise timing, though deterministic hardware may alternatively control all operations using lookup tables and precalculated patterning paths.

[0139] The stage 190, which functions to support the substrate material 170 and position the substrate material 170 relative to the objective lens 160, maybe movable along one or more axes to translate or rotate the substrate material 170 during patterning. In some variations, the stage 190 may provide motion along three linear axes (X, Y, Z) for Cartesian patterning. The stage 190 may provide continuous motion for lateral translation of the patterning plane relative to the substrate material 170.IRRA-M05-PCT

[0140] In some variations, the stage 190 maybe specially configured to reflect the symmetries and parameters of lithography objectives and may provide motion along an angular axis, a radial axis, and an axial Z axis for patterning cylindrical geometries. This configuration may provide degrees of freedom for patterning that align or conform to a cylindrical or rounded component geometry, and maybe particularly suited for fabrication of optical components or other devices having cylindrical overall shapes. For example, if the angular arc is a full 360 degrees, the system may pattern a three-dimensional annular volume with a height in Z defined by the patterning plane tilt. After sweeping through an angle, the field of view maybe repositioned in radius or in Z before sweeping through another angular region. The angular sweep speed maybe adjusted as a function of radius to maintain relatively constant exposure time. The patterning may remain fully arbitrary, as the dosage may be changed for each individual voxel within the patterned volume. This configuration may minimize stitching errors or wasted space for cylindrical device volumes.

[0141] As shown in FIG. 12, in some variations, the stage 190 may provide motion along six axes for patterning arbitrary geometries. A six-axis stage, such as a hexapod stage, may enable patterning into oddly shaped or non-Cartesian geometries. The hexapod configuration may support the substrate material 170 on a wafer mount while the objective lens 160 directs the laser beam to the patterning plane. This arrangement may enable arbitrary positioning and orientation of the substrate material 170 relative to the patterning beam. For example, the stage 190 may rotate in two angular dimensions and translate in one spatial dimension to pattern spherical or shell-like volumes or surfaces.

[0142] In some variations, the patterning plane may be configured to fully lie within a defined lateral XY plane and be orthogonal to a defined axial Z axis. In other variations, the system 100 maybe configured with a patterning plane that is tilted with respect to the XY plane. This configuration may enable the system 100 to pattern a full three-dimensional volume with thickness greater than the single voxel axial resolution via lateral translation of the patterning plane relative to the substrate material (e.g., scanning the patterning plane continuously in the lateral XY directions). Since fabricated devices are typically larger in the lateral directions than the axial directions,IRRA-M05-PCT tilted plane patterning allows for longer continuous sweeps compared to scanning through Z before moving laterally, resulting in smaller stitching boundaries, thus increasing throughput and reducing stitching errors and defects.

[0143] As shown in FIG. 11, tilting the substrate material 170 (e.g., a wafer) and translating both vertically and horizontally via the stage 190 causes printing along a diagonal path through the substrate material 170. The objective lens 160 focuses a laser beam shaped into a DMD-matched pattern onto the tilted wafer, and as the wafer is moved in both the X and Z directions via a translation stage, patterned material is deposited along a diagonal trajectory. This approach may maximize or enhance the distance along which the system too can print such that the translation stage must accelerate or decelerate minimally, with acceleration and deceleration occurring primarily at the edges of the wafer rather than throughout the patterning process.

[0144] In some variations, the three-dimensional volume within the substrate material 170 may span multiple Z-depths during lateral translation, the thickness of the volume being greater than an axial resolution of a single voxel.

[0145] The tilted patterning plane configuration may be achieved through several implementations. In one variation, the system 100 may include a tilted mirror for remote focal plane manipulation (also referred to as a remote focusing mirror) tilted slightly with respect to the optical axis to establish the tilted patterning plane. In another variation, the system 100 may include a phase plate in an optical path between the digital mask system 140 and the objective lens 160, the phase plate establishing the tilted patterning plane. In yet another variation, an optical axis of the objective lens 160 may be rotated with respect to the XY plane of the substrate material 170.

[0146] In some variations, the stage 190 may provide continuous motion for the lateral translation of the patterning plane relative to the substrate material 170, enabling continuous patterning of three-dimensional volumes, which can reduce stitching boundaries compared to step-and-repeat patterning approaches.

[0147] In some variations, patterning of the light and thereby substrate material patterning may be a binary pattern (e.g., on / off). In other variations, the controller 180 may vary optical exposure delivered to different voxels within the substrate material 170 by coordinating patterning across one or more sweeps to produce a plurality of discreteIRRA-M05-PCT exposure levels spanning a range from a minimum exposure level to a maximum exposure level. A single plane pattern may be determined by the binary on-off signal of pixels on the digital mask system 140 being turned on or off.

[0148] In some variations, the controller 180 may coordinate N sweeps over a patterning field at binary- weighted power levels to achieve 2AN discrete exposure levels using only log2(N) sweeps by using the additive nature of the patterning process. For example, only three different laser power sweeps may be used to achieve 8 discrete exposure levels. A zero power level may be achieved by keeping a pixel off during all sweeps. The first power level may be achieved by setting the laser power corresponding to 1 / 7 of the maximum. The second level maybe achieved by setting the laser power to 2 / 7 of the maximum. The third level may be achieved by having a pixel on for both the 1 / 7 and 2 / 7 sweeps, leading to a total of 3 / 7. The fourth level may be achieved by setting the laser power to 4 / 7. The fifth level may come from a combination of the 1 / 7 and 4 / 7 powers, achieving 5 / 7 of the maximum power. The sixth level maybe achieved by combining 4 / 7 and 2 / 7, and the final level may be achieved by combining all three of 1 / 7, and 4 / 7. This scheme is general and maybe used to achieve any N=2An discrete exposure levels in n=log2(N) patterning sweeps.

[0149] In practice, the additive levels may not be purely linear due to various nonlinearities. The same effect maybe achieved empirically by trying different single power sweeps and then combinations of powers, measuring the resulting exposure levels, and tuning until the desired evenly or non-evenly spaced levels are achieved.

[0150] In some variations, the system too may include a power modulation element in the optical path between the optical pulse source 110 and the digital mask system 140. The power modulation element may comprise an electro-optic modulator (EOM) or an acousto-optic modulator (AOM). The EOM or AOM maybe used to modulate the overall beam power to a desired level, and then only the pixels with that desired level may be switched on. This may then be repeated for N levels of exposure. Alternatively, the power may be set to a constant minimum level, and then swept over the digital mask system 140 N times, with each sweep adding more exposure to desired sets of pixels, to reach N levels of exposure.IRRA-M05-PCT

[0151] As shown in FIG. 8B, in some variations, the projection optics 150 maybe arranged such that an MxM array of pixels on the digital mask system 140 corresponds to a single diffraction-limited spot in the patterning plane, forming a "super-pixel." One way for achieving grayscale is by focusing multiple pixels on the DMD down to one effective super-pixel in the sample plane. By turning on pixels fractionally within the super-pixel, fractional powers may be delivered to the same voxel in the sample plane, which can allow for causing partial polymerization that changes the refractive index in a controlled fashion. FIG. 8B illustrates different shapes of super-pixels that may be created on the DMD, showing various binning patterns including linear arrangements, L-shaped arrangements, and block arrangements. For example, if a 2x2, 3x3, or 4x4 set of pixels is optically configured to correspond to a diffraction-limited spot in the patterning plane, then changing the number of on mirrors within that diffractionlimited spot may change the total dosage reaching that spot, allowing for up to 4, 9, or 16 discrete exposure levels respectively from only a single sweep of the digital mask system 140.

[0152] As shown in FIG. 8C, in some variations, variable exposure may be achieved by mapping one DMD to another DMD. Typically, when a DMD is illuminated by a laser line that is mechanically scanned, because the DMD pixels can only turn "on" or "off," fractional powers cannot be delivered to individual pixels in traditional approaches. However, by mapping a row of a first DMD to pixels on a second DMD, grayscale becomes possible. FIG. 8C illustrates this mapping concept, showing how a pattern on the first DMD corresponds to fractional power levels delivered to pixels on the second DMD.

[0153] As shown in FIG. 8D, one optical configuration for implementing DMD-to-DMD mapping includes a polarizing beam-splitter and quarter waveplate that deliver light to a spatial light modulator (SLM) that shapes the light into a rectangle. The shaped light passes through a Fourier transform lens to illuminate a first DMD (DMD 1). The first DMD has a defined region of interest (ROI) of approximately 16 pixels wide, which can switch its mirrors at a maximum speed of approximately 85 kHz (faster than a full-chip DMD since it uses only a fraction of the chip). Light from the first DMD passes through a cylindrical lens to focus vertically, then to a polygon scanner whichIRRA-M05-PCT mechanically scans the light. A scan lens collects the light, which then passes through a cylindrical lens to focus into a line and a shaping telescope to match the second DMD's vertical size. The light is directed via a mirror to a second DMD (DMD 2), which uses its entire chip area. The second DMD's full chip is scanned with a mapping of first DMD pixels. The modulated light then passes through a tube lens to an objective lens for delivery to the sample.

[0154] By carefully balancing and synchronizing the DMD switch speeds and patterns, polygon spin speeds, and laser pulse train, a "mosaic" of fractional powers may be delivered to the sample, enabling grayscale patterning in the sample plane.

[0155] All of these different exposure control methods may be characterized empirically or simulated theoretically, or a combination thereof, to create a lookup table that may then be used during the lithography process itself. The lookup table may correlate exposure parameters to resulting exposure levels in the substrate material 170.

[0156] As shown in FIG. 9, the beam profile in and out of the digital mask system 140 may be important to achieve high quality patterning. FIG. 9 illustrates an active beam shaping configuration in which a processing controller is connected to a spatial light modulator (SLM). The SLM shapes the incoming laser beam, which may produce multiple lines or varied line shapes. The shaped beam passes to a polygon scanner, which directs the beam to a DMD. Modulated light from the DMD passes through a dichroic element and is directed to an objective lens for focusing onto a sample. An in-situ sensing subsystem (for wavefront sensing, imaging, etc.) receives light from the dichroic and provides feedback to the processing controller. The processing controller adjusts the SLM based on the sensed beam profile to correct for aberrations during scanning, enabling dynamic optimization of the line shape.

[0157] Prior to the digital mask system 140, the beam profile may be a flat-top beam, which may be achieved with standard or active phase / amplitude flat-top converters to convert the input Gaussian beam of the laser to a flat -top beam so that the entire patterning field has even illumination. For example, this may use an off-the-shelf Gaussian-to-flat-top mode converter. However, if more control or precision is desired, this may instead be achieved using an active spatial light modulator or adaptive mirror array coupled to a sensor with a feedback loop to optimize the profile. The system 100IRRA-M05-PCT may include a spatial light modulator in a beam path between the optical pulse source no and the digital mask system 140, a sensor measuring a beam profile of the lineshaped beam, and a feedback controller coupling the sensor to the spatial light modulator and adjusting the spatial light modulator to correct for aberrations during scanning.

[0158] Out of the digital mask system 140, due to manufacturing tolerances of individual MEMS mirrors on a DMD, there maybe higher-order errors and individual differences in the reflectivity of each individual mirror pixel. To address this challenge, a static amplitude mask maybe manufactured (custom for each DMD / lithography system) after testing the DMD. An alternate solution maybe to implement dithering with the DMD for each plane that is being patterned.

[0159] Stitching errors are traditionally a challenge for nanolithography. Some variations of the system 100 may reduce or even eliminate stitching errors by using active alignment and feedback. One source of stitching error is error in the stage position control. High-precision stages are typically able to measure their position far more accurately (e.g., single nanometers) than they are able to actually position it (e.g., bidirectional repeatability greater than 10 nm). Thus, one method of correcting stitching errors using feedback is to slightly adjust the pattern image location based on the stage position measurement. The system 100 may include a position feedback system measuring a position of the stage 190, and the controller 180 may adjust a location of the projected modulated light within the substrate material 170 based on the measured position. The position feedback system may include stage position sensors (e.g., encoders, interferometers) that measure the physical position of the stage 190 with high accuracy. Alternatively or additionally, the position feedback system may include optical feedback components that detect signals from the substrate material 170, such as fluorescence from previously patterned locations or refractive index changes detectable via phase contrast microscopy. The optical feedback components may share imaging capabilities with the imaging system described herein, using the same optical path through the objective lens 160 and similar imaging modalities.

[0160] In one variation, the system 100 may use a DMD on an XY piezo stage with at least one pixel (e.g., approximately 10 microns) of movement. For any given positionIRRA-M05-PCT error, integer pixel errors may be accounted for by shifting the location of the pattern on the DMD by an integer number of pixels, and then remaining sub-pixel errors may be quickly and accurately accounted for by using the piezo stage to shift the DMD position with nanometer-scale accuracy.

[0161] Another variation for active correction may be to use a pair of galvo mirrors to slightly shift the location of the digital mask image in the patterning plane.Alternatively, movable, shifting, or tunable lenses may be used. Another variation for active correction maybe to use pixel-shift technology such as voice-coil motors (VCM) to slightly shift the location of the digital mask image in the patterning plane.

[0162] In some variations, the position feedback system may measure fluorescence from previously patterned locations within the substrate material 170. Fluorescence information maybe collected through the patterning objective lens 160 and used to align with fluorescence information from the patterning process itself, leading to fast and accurate alignment with minimal stitching error. Other techniques that are sensitive to small refractive index changes due to the patterning process, such as phase contrast microscopy, may also be used for this feedback.

[0163] As shown in FIG. 13, some variations of the system 100 may use a remote focal plane manipulation configuration. Remote focal plane manipulation (which may be referred to or relate to remote focusing) may enable changing the patterning plane in the substrate material 170 without moving the objective lens 160 or the substrate material 170 itself. If a translation stage holding the substrate material 170 is moved only vertically (in the Z direction), the resulting print planes may come out angled with respect to the substrate surface. However, if the print plane can be dynamically tilted via remote focal plane manipulation, flat print planes maybe achieved even during vertical-only stage translation.

[0164] The tilt compensation may be accomplished by a deformable mirror or a phase plate positioned in the optical path. In the configuration shown in FIG. 13, light from multiple DMDs (e.g., DMD 1 and DMD 2) is directed to a deformable mirror or phase plate, which then directs the combined beam to the objective lens 160. The deformable mirror may rapidly adjust the print plane tilt during patterning. As the sample translates down in the Z direction over time, a first pair of DMDs (e.g., DMDs 1IRRA-M05-PCT and 2) may print a tilted layer, then a second pair of DMDs (e.g., DMDs 3 and 4) may print, and the sequence may repeat. With tilt compensation via the fast deformable mirror, the tilted print plane compensates for the stage motion to produce flat patterned layers in the substrate material 170. This tilt compensation approach may alternatively be achieved with nonlinear crystals or specific phase plates.

[0165] The secondary objective or another optical element within the remote focal plane manipulation system may be mounted on a piezoelectric or motorized actuator that can quickly and precisely move along the optical axis. This may cause the patterning plane within the substrate material 170 to shift remotely without physically moving the substrate material 170 or primary objective lens 160.

[0166] This shift may be synchronized with the imaging system to ensure that focus adjustments occur smoothly and in synchronization with the pattern on the digital mask system 140. The benefit maybe to provide faster random access along the optical axis, as a small element like a mirror can be moved very quickly, rather than a larger and heavier element like an objective or the sample. This may be especially useful for patterning structures that are relatively sparse along the optical axis.

[0167] In traditional approaches, a patterned object is printed completely, moved to a secondary measurement device (such as an X-ray CT scanner), and subjected to complex three-dimensional reconstruction calculations. This process is typically slow and may take hours, days, or more. In some variations, the system 100 may include a phase measurement subsystem measuring optical path length through the substrate material 170 after each patterning pass. The phase measurement subsystem may capture two-dimensional optical path difference (OPL) measurements after each new layer is patterned. The controller 180 may determine a phase profile of each patterned region by subtracting successive optical path length measurements. This subtractive approach may enable in-situ phase measurement without requiring complex three-dimensional reconstruction or removal of the substrate material 170 from the patterning system.

[0168] The system 100 may additionally include dynamically adjustable dispersion, which may function to optimize or otherwise enhance temporal focusing performance. The dispersion of the system 100 may be adjusted automatically during operation as aIRRA-M05-PCT function of different conditions, such as depth into the sample, temperature, laser power, or other factors. The controller 180 or another system may integrate with an electronically controlled dispersive element where the degree of dispersion compensation is changed as a function of these parameters, either with open-loop or closed-loop feedback.

[0169] In some configurations, light after the digital mask system 140 in a temporally focused line-scan system maybe spatially separated by wavelength, based on different wavelength-dependent diffraction angles from the digital mask system 140. The different wavelengths may also travel different effective optical path lengths, based on the dispersion and spatial path lengths of the different optical paths. The result maybe some differences in the time at which different wavelengths arrive at the focal spot in the patterning plane, negating some of the effect of temporal focusing. To compensate for such occurrences, the system too may include a specially designed spatial phase plate or prism-based dispersion compensation device in the optical path between the digital mask system 140 and the objective lens 160.

[0170] In some variations, the system too may achieve an effectively higher repetition rate by introducing a delay line, whereby pulses are either split or picked, with one or more beam paths being delayed with respect to the primary beam path. The system 100 may include a beam splitter splitting the pulsed light beam into a first portion and a second portion, and an optical delay line delaying the second portion relative to the first portion, increasing an effective repetition rate of optical pulses delivered to the substrate material 170. This delay maybe accomplished through means such as many bounces between mirrors, propagation through a long fiber, and / or other approaches for introducing a delay. This may also be combined with other complementary solutions, such as using multiple lasers.

[0171] As an illustrative example, a 2 MHz repetition rate laser has a separation of 500 ns between pulses. The laser beam may be separated using a standard 50 / 50 beamsplitter, and then one path may have an effective optical path length of about 150 meters longer than the other path, corresponding to a temporal delay of 250 ns. This optical path length difference may be achieved by, for example, bouncing the light between two mirrors separated by 2 meters and at such an angle that it bounces 75IRRA-M05-PCT times. The two beam paths may then be recombined, effectively doubling the repetition rate to 4 MHz.

[0172] As shown in FIG. 14A, in some variations, when an ultrafast pulse is split into two pulses with a short delay between them (a "pump" pulse and a "probe" pulse), the energy per pulse required to pattern the substrate material 170 may be reduced. This pump-probe configuration maybe implemented using a Mach-Zehnder interferometer where one arm includes mirrors on a translation stage or delay line. The delay between pulses may be adjustable between approximately 40 femtoseconds to multiple picoseconds. This configuration may manipulate fast dynamics of the substrate material 170 to aid patterning, with the goal of reducing patterning threshold energy rather than increasing effective repetition rate. The optical path may include a non-polarizing beamsplitter to split the incoming beam, a half-wave plate and thin film polarizer for polarization control, and a polarizing beam-splitter to recombine the two delayed pulses before delivery to the digital mask system 140.

[0173] In some variations, one or more beams (e.g., either or both beams) may be shaped via spatial light modulators. An example output beam could be one that has helical wavefronts (such as Laguerre-Gaussian beams, which carry orbital angular momentum). When used appropriately in pump-probe setups, such beams may potentially aid or enhance patterning by taking advantage of fast material dynamics.

[0174] As shown in FIG. 14B, in some variations, a similar Mach-Zehnder interferometer configuration may include a beta barium borate (BBO) crystal in one arm and a delay stage in the other arm. The BBO crystal may frequency-double the beam to achieve a different wavelength (second harmonic generation). By tuning the separation between the fundamental pulse and the frequency-doubled pulse, the pulse energy required to pattern maybe reduced. The two wavelengths maybe combined using dichroic mirrors before delivery to the digital mask system 140. Frequency doubling using nonlinear crystals such as BBO is a well-established technique in ultrafast optics.

[0175] As shown in FIG. 17, in some variations, lasers with low fixed repetition rates that can be triggered may have their outputs combined to increase effective repetition rate. The system 100 may include multiple pump and amplifier pairs within a laser head, with each pair outputting a pulsed beam. The outputs may be sequentiallyIRRA-M05-PCT combined using electro-optic modulators (EOMs), half-wave plates (HWPs), and polarizing beamsplitters (PBSs). The half-wave plates and polarizing beamsplitters may reflect p-polarized light, and the EOMs may switch polarizations to s-polarization at the correct times. The EOMs and laser heads may be triggered from one of the beams to synchronize the polarization of the reflected pulses such that all output pulses have the same polarization, enabling efficient combination of multiple laser sources into a single output beam with increased effective repetition rate.

[0176] As shown in FIG. 16A, in some variations, the system 100 may achieve patterning resolution finer than the diffraction limit by using an activation-deactivation approach. In this configuration, the beam-splitting architecture described above may direct one beam path through an optical parametric amplifier (OPA) to generate a different wavelength. The two wavelengths may be independently delivered to separate DMDs, with one wavelength functioning as an activation beam to start the patterning process and the other wavelength functioning as a deactivation beam to stop the patterning process.

[0177] As shown in FIG. 16B, the fields of view (FOVs) of the two DMDs may be tiled over each other, and light may be switched in time such that there is a light distribution that activates patterning and an inverse light distribution that deactivates patterning. What remains after the activation and deactivation process is a patterned region that is more precise than would be achieved using the patterning beam alone.

[0178] Some variations of the system 100 may use lithography on top of and / or registered to another substrate. This variation may include imaging the underlying substrate, which may make it possible to lithographically align and print directly onto or around existing structures. This may be done on top of a fiber, photonic integrated circuit (PIC), integrated circuit (IC), or other substrates. The system 100 may include an imaging system registering patterning location to existing structures on or within the substrate material 170. Imaging maybe done using a variety of modalities that may either be separate or integrated with the optical path of the lithography system. For example, imaging modalities may include confocal, fluorescence, two-photon fluorescence, darkfield, brightfield, differential interference contrast (DIC), phase imaging, or other techniques. In some variations, the imaging system may share anIRRA-M05-PCT optical path with the projection optics 150 and the objective lens 160 via a dichroic element, enabling in-situ imaging during patterning.

[0179] It is also possible to perform active alignment, in which light is sent through the structure of interest and used for alignment. For example, the light cone from a fiber may be used to precisely align to the center location and angle of the fiber. This may also be done for PIC structures such as waveguides and grating couplers. Further, it may be possible to use the small index contrast created by polymerization (typically dn less than 0.1) to create optical structures specifically for the purpose of alignment or calibration.

[0180] A two-photon process may only result in the absorption and loss of a relatively small amount of the total light, typically less than 5%. In some variations, the system 100 may recycle pulses by collecting the light from the back end of the substrate material 170 and recycling it through the patterning system back onto the substrate material 170. This pulse recycling system may require modulation or compression of the pulse after the substrate material 170, as well as other optical corrections or delays.3. Method

[0181] As shown in FIG. 19, a method for multi-photon lithography may include generating S110 a pulsed light beam from an optical pulse source, shaping S120 the pulsed light beam into a line-shaped beam having an elongated cross-section, scanning S130 the line-shaped beam across a digital mask comprising an array of individually addressable elements, modulating S140 the line-shaped beam via the digital mask according to a spatial pattern, projecting S150 modulated light from the digital mask through projection optics and an objective lens to a patterning plane within a substrate material, and altering S160 the substrate material at the patterning plane via multiphoton absorption.

[0182] As shown in FIG. 20, in some variations wherein the digital mask comprises a first DMD and a second DMD, scanning S130 the line-shaped beam across the digital mask may include directing S132 the line-shaped beam to the first DMD during a first time period and directing S134 the line-shaped beam to the second DMD during aIRRA-M05-PCT second time period. This may enable refreshing a pattern on the first DMD while directing light to the second DMD for patterning.

[0183] As shown in FIG. 21, in some variations, the method may further include varying optical exposure delivered to different voxels within the substrate material by coordinating S142 patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level. Coordinating patterning may include performing N sweeps over a patterning field at binary- weighted power levels to achieve 2AN discrete exposure levels.

[0184] As shown in FIG. 22, in some variations wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, the method may further include laterally translating S152 the patterning plane relative to the substrate material to pattern a three-dimensional volume within the substrate material. Laterally translating may include continuous translation to reduce stitching boundaries.

[0185] In some variations, the line-shaped beam may form a focal line tilted greater than 30 degrees with respect to a scan direction, the focal line aligned with a pixel array axis of the digital mask for operation in a blazed grating condition.

[0186] In some variations, the method may further include measuring a beam profile of the line-shaped beam, adjusting a spatial light modulator based on the measured beam profile to correct for aberrations, and repeating the measuring and adjusting during scanning.

[0187] The method may be implemented through a system variation described herein, though any suitable system may alternatively implement the method.

[0188] The method variations described herein may be used in combination. For example, the method using multiple DMDs maybe combined with varying optical exposure to achieve grayscale patterning at high throughput. The method using multiple DMDs may be combined with a tilted patterning plane for continuous three-dimensional volume patterning. The method using variable exposure levels may be combined with a tilted patterning plane to pattern three-dimensional volumes with controlled exposure gradients. In some variations, the method may combine all three key differentiators: using multiple DMDs for throughput, varying optical exposure forIRRA-M05-PCT discrete exposure level control, and tilting the patterning plane for continuous three-dimensional volume patterning with reduced stitching.

[0189] Block S110, which includes generating a pulsed light beam from an optical pulse source, functions to provide optical energy for multi-photon absorption within the substrate material. Generating S110 may include producing femtosecond or picosecond pulses at a repetition rate suited for multi -photon absorption. The pulsed light beam may be generated at wavelengths in the near-infrared range. The pulse duration, repetition rate, and wavelength may be selected based on the multi -photon absorption characteristics of the substrate material. Generating S110 provides the pulsed light beam that is subsequently shaped S120 and scanned S130 across the digital mask.

[0190] Block S120, which includes shaping the pulsed light beam into a line-shaped beam having an elongated cross-section, functions to transform the beam profile for line-scan patterning across the digital mask. Shaping S120 may include passing the pulsed light beam through line-forming optics such as cylindrical lenses, diffractive optical elements, or other beam-shaping components. The line-shaped beam produced by shaping S120 is then directed by scanning S130 across the digital mask. In some variations, shaping S120 may produce multiple parallel lines or other patterns using cylindrical lens arrays or diffractive optical elements.

[0191] Block S130, which includes scanning the line-shaped beam across a digital mask comprising an array of individually addressable elements, functions to sweep the line-shaped beam across the digital mask to enable sequential patterning. Scanning S130 may include directing the line-shaped beam via a scanning system to sweep the beam across the array of individually addressable elements. As the line-shaped beam sweeps across the digital mask during scanning S130, the digital mask modulates S140 the beam according to a spatial pattern synchronized with the scan position.

[0192] In some variations, scanning S130 may include directing the line-shaped beam via a rotating polygon scanner having multiple reflective faces. As the polygon rotates, each reflective face sweeps the line-shaped beam across the digital mask system. Directing the line-shaped beam may include using a plurality of polygon scanners arranged in parallel or in series. The plurality of polygon scanners may be operated in-phase or out-of-phase to reduce dead time at polygon face transitions.IRRA-M05-PCT

[0193] Block S140, which includes modulating the line-shaped beam via the digital mask according to a spatial pattern, functions to impart patterning information onto the line-shaped beam. Modulating S140 may include selectively activating addressable elements of the digital mask to control which portions of the line-shaped beam are transmitted or reflected toward the substrate material and which dispersed. The spatial pattern applied during modulating S140 may correspond to a desired two-dimensional slice of a three-dimensional structure to be patterned. Modulating S140 occurs in coordination with scanning S130, with the digital mask pattern updated as the lineshaped beam sweeps across the digital mask. The modulated light produced by modulating S140 is then projected S150 to the patterning plane.

[0194] In some variations using multiple DMDs, modulating S140 may include refreshing a pattern on a first DMD while directing light to a second DMD for patterning. Then subsequently refreshing a pattern on the second DMD while directing light to the first DMD for patterning. Scanning S130 may be broken into substeps: directing S132 the line-shaped beam to the first DMD during a first time period, and directing S134 the line-shaped beam to the second DMD during a second time period. When using a polygon scanner, rotation of the polygon scanner may cause different reflective faces to perform directing S132 and directing S134 to alternate between DMDs.

[0195] In some variations, a first DMD and a second DMD maybe tiled in an image plane such that their respective fields of view are adjacent. In some variations, the method may include switching between a plurality of DMD sets, wherein each DMD set comprises multiple tiled DMDs.

[0196] Block S150, which includes projecting modulated light from the digital mask through projection optics and an objective lens to a patterning plane within a substrate material, functions to deliver the patterned light to the substrate material for multiphoton absorption. Projecting S150 may include passing the modulated light through projection optics and an objective lens to focus the modulated light onto the patterning plane. Projecting S150 may include demagnifying the pattern from the digital mask to achieve the desired feature size at the patterning plane. The focused light delivered byIRRA-M05-PCT projecting S150 enables altering S160 the substrate material via multi-photon absorption.

[0197] Block S160, which includes altering the substrate material at the patterning plane via multi-photon absorption, functions to create the patterned structure within the substrate material. Altering S160 may include inducing localized chemical or physical changes within the substrate material at locations where the focused light intensity exceeds the multi-photon absorption threshold. The alterations produced during altering S160 may include polymerization, binding of chromophore molecules, reduction of metal salts, or other photochemical processes depending on the substrate material composition. Altering S160 is the culmination of the preceding steps, with the pattern defined by modulating S140, the position controlled by scanning S130, and the energy delivered by generating S110, shaping S120, and projecting S150.

[0198] The method may include patterning with varying exposure levels to effectively enable grayscale patterning within the substrate material. Varying optical exposure delivered to different voxels may be achieved by coordinating S142 patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level. In some variations, coordinating S142 patterning comprises performing N sweeps over a patterning field at binary- weighted power levels to achieve 2Z'N discrete exposure levels. For example, N may equal 3 and the binary-weighted power levels may comprise approximately (e.g., + / -io%) 1 / 7, 2 / 7, and 4 / 7 of a maximum power level, achieving 8 discrete exposure levels. Alternatively, varying exposure may include using pixel binning, wherein an MxM array of pixels on the digital mask corresponds to a single diffraction-limited spot in the patterning plane, and varying the number of active pixels within the MxM array varies the exposure level delivered to the diffraction-limited spot. The method may include modulating power of the pulsed light beam via an EOM or AOM for each sweep. The method may further include calibrating exposure parameters using a lookup table correlating exposure parameters to resulting exposure levels.

[0199] The method may include patterning using a tilted patterning plane oriented at a tilt angle with respect to an XY plane of the substrate material, enabling patterning of a three-dimensional volume via lateral translation of the patterning plane relative to theIRRA-M05-PCT substrate material. By tilting the patterning plane, laterally translating S152 the patterning plane may result in the three-dimensional volume within the substrate material spanning multiple Z-depths, the thickness of the volume being greater than an axial resolution of a single voxel. Laterally translating S152 may comprise continuous translation to reduce stitching boundaries compared to step-and-repeat patterning. The method may further include repositioning the patterning plane along an axial direction via remote focal plane manipulation (also referred to as remote focusing) without moving the objective lens or the substrate material.

[0200] The method may include active alignment to maintain accurate positioning during patterning. Active alignment may include measuring a position of a stage supporting the substrate material and adjusting a location of the projected modulated light within the substrate material based on the measured position. This active feedback may reduce stitching errors between adjacent patterned regions and compensate for stage drift or thermal expansion. In some variations, measuring may comprise detecting fluorescence from previously patterned locations within the substrate material, enabling alignment to previously patterned features.

[0201] The method may include in-situ phase measurement to characterize patterned structures during fabrication. Phase measurement may include measuring optical path length through the substrate material after each patterning pass and determining a phase profile of each patterned region by subtracting successive optical path length measurements. This subtractive approach may isolate the phase contribution of each newly patterned layer from the cumulative optical path length.

[0202] The method may include increasing effective pulse repetition rate using an optical delay line. The delay line approach may include splitting the pulsed light beam into a first portion and a second portion, delaying the second portion relative to the first portion via an optical delay line, and recombining the first and second portions. By temporally offsetting pulse copies, the effective repetition rate delivered to the substrate material maybe doubled or further multiplied depending on the number of delay stages.

[0203] The method may include patterning cylindrical or rotationally symmetric geometries within the substrate material. Cylindrical patterning may include scanning along an angular axis, a radial axis, and an axial Z axis. This cylindrical coordinateIRRA-M05-PCT scanning may enable fabrication of structures such as optical fibers, cylindrical lenses, or other rotationally symmetric components.

[0204] The method may include registering patterning to existing structures on or within the substrate material. Registration may include imaging existing structures on or within the substrate material and aligning patterning location to the existing structures. This may enable patterning relative to pre-existing features such as alignment marks, waveguides, or other previously fabricated components. In some variations, imaging may be performed in-situ during patterning via a shared optical path with the patterning optics, enabling real-time registration without removing the substrate material from the patterning system.

[0205] The method may include synchronizing the optical pulse source, the scanning system, and the digital mask using a primary timing reference. The primary timing reference may be derived from one of the optical pulse source, the scanning system, the digital mask, or a stage supporting the substrate material. Synchronizing may comprise aligning timing, phase, or frequency of subsystems using one or more phase-locked loops (PLLs) or other synchronization mechanisms to ensure coordinated operation between laser emission, beam positioning, and modulation. In some variations, the method may include monitoring a position or phase of the scanning system, wherein the primary timing reference is derived from the monitoring. Monitoring may include detecting a reference point on the scanning system using a synchronization light source and photodetector (e.g., detecting start-of-scan, end-of-scan, or another phase reference). In some variations, synchronization may be established based on multiple signals rather than a single reference. For example, two or more timing sources (e.g., laser pulse timing and scanner position) may be jointly considered to determine system timing, enabling hybrid or adaptive synchronization schemes that may improve robustness to drift, latency, or dynamic variations in system behavior.

[0206] The method may include executing one or more control loops to coordinate subsystem operation. A given implementation may employ any one of the control loops described below, or any combination thereof, depending on system architecture and application requirements.IRRA-M05-PCT

[0207] The method may include executing a laser pulse timing synchronization loop to synchronize laser pulse emission with the instantaneous spatial position of the beam. The method may include receiving laser timing reference, scanner position and / or phase, stage position and velocity, digital mask synchronization signals, and / or linestart or pixel-start triggers. The method may include generating AOM and / or EOM gating signals, laser trigger or burst trigger signals, and / or timing or phase offset corrections to emit pulses at intended spatial coordinates, maintain constant spatial pulse spacing, and / or compensate for latency and jitter.

[0208] The method may include executing a pulse-to-position synchronization loop to convert spatial exposure requirements into pulse timing based on real-time motion. The method may include receiving scanner position, stage position, scanner speed error, stage speed error, and / or commanded pulse pitch or line density. The method may include generating position-based trigger signals, resampled timing clock, AOM or EOM gating patterns, and / or scanner phase trim to maintain constant pulses-per-unit-length or energy-per-unit -length, and / or compensate for velocity variations.

[0209] The method may include executing a laser power regulation loop to stabilize optical power delivered to the substrate material. The method may include receiving measured laser power, commanded power setpoint, pulse repetition mode and width, and / or in-situ monitoring signals. The method may include generating AOM drive amplitude, EOM control signals, and / or laser power commands to reject source drift, maintain stable average and / or peak power, and / or compensate for scan conditions.

[0210] The method may include executing a fluence or dose-per-unit-length regulation loop to maintain consistent deposited energy along a scan. The method may include receiving laser power, scan velocity, spot or line dimensions, pulse spacing, and / or in-situ monitoring signals. The method may include generating laser power adjustments, gating duty cycle modifications, and / or scan speed corrections to maintain target fluence despite motion variations.

[0211] The method may include executing a scanner position control loop to ensure the scan trajectory matches a commanded path. The method may include receiving scanner position feedback, scanner detection signals, and / or commanded trajectory.IRRA-M05-PCT The method may include generating scanner drive commands and / or phase corrections to minimize tracking error and / or maintain spatial accuracy.

[0212] The method may include executing a scanner velocity control loop to regulate instantaneous scan speed. The method may include receiving scanner speed feedback and / or commanded velocity profile. The method may include generating scanner drive commands and / or phase compensation signals to maintain constant scan velocity during exposure.

[0213] The method may include executing a scanner phase synchronization loop to align scanner motion with laser timing and digital mask signals. The method may include receiving scanner position, laser timing, pixel or line clock, and / or digital mask synchronization signals. The method may include generating scanner phase control signals, trigger phase offsets, and / or gating alignment signals to ensure spatial-temporal alignment of exposure.

[0214] The method may include executing a stage position control loop to control translation stage position for large-area processing. The method may include receiving stage position feedback, commanded position, and / or alignment references. The method may include generating stage motor commands and / or feedforward terms to maintain positioning accuracy and stitching consistency.

[0215] The method may include executing a stage velocity control loop to maintain stage speed during coordinated scanning. The method may include receiving stage speed, speed error, and / or commanded feed rate. The method may include generating velocity or acceleration commands to synchronize stage motion with scanning.

[0216] The method may include executing a stage acceleration and jerk control loop to ensure smooth motion profiles. The method may include receiving stage position, velocity, acceleration, and / or motion profile. The method may include generating acceleration and jerk-limited commands to reduce vibration and transient positioning error.

[0217] The method may include executing a stage-scanner synchronization loop to coordinate scanner motion with stage motion. The method may include receiving scanner position and velocity, stage position and velocity, and / or process state. TheIRRA-M05-PCT method may include generating stage feed commands, scanner offsets, and / or stitch corrections to maintain continuous effective scan field and minimize stitching artifacts.

[0218] The method may include executing a beam alignment and steering loop to maintain optical alignment of the beam and spatiotemporal focus. The method may include receiving beam diagnostics, in-si tu monitoring signals, and / or mirror mount position. The method may include generating motorized mirror mount control signals to compensate drift and maintain beam alignment.

[0219] The method may include executing a digital mask alignment and stitching loop to align digital exposure patterns with physical scan and ensure seamless stitching. The method may include receiving digital mask data, scanner position and phase, stage position and velocity, fiducial or registration signals, and / or field transition signals. The method may include generating mask synchronization signals, timing or phase offsets, and / or stitch correction parameters to maintain alignment between the digital mask and beam position, and / or ensure continuity across scan regions.

[0220] The method may include executing a pulse shape and width control loop to regulate temporal pulse characteristics. The method may include receiving pulse shape and width measurements, laser timing, and / or process feedback. The method may include generating pulse shaping commands, modulator control signals, and / or dispersion or compression settings to maintain desired temporal pulse profile.

[0221] The method may include executing a spatiotemporal focus (STF) optimization loop to maintain optimal spatiotemporal recompression at the substrate material. The method may include receiving in-situ monitoring signals, beam diagnostics, and / or pulse characteristics. The method may include generating dispersion compensation adjustments, alignment adjustments, and / or laser parameter tuning to maximize energy localization at the focal point.

[0222] The method may include executing an in-situ process feedback loop to adapt processing based on real-time material response. The method may include receiving optical, acoustic, thermal, or imaging signals, and / or system state. The method may include generating power, timing, or speed adjustments, and / or fault signals to compensate material variability and detect process deviations.IRRA-M05-PCT

[0223] The method may include executing a feature registration and overlay control loop to align features across scans or layers. The method may include receiving fiducial measurements, and / or stage and scanner position. The method may include generating position offsets and / or mask phase corrections to maintain overlay accuracy.

[0224] The method may include executing a safety, fault, and exposure interlock loop to ensure safe operation and prevent unintended exposure. The method may include receiving system readiness signals, interlocks, and / or fault conditions. The method may include generating laser inhibit or shutter commands, motion stop commands, and / or fault latch signals to transition the system to a safe state under fault conditions.

[0225] In some variations, the method may include hierarchical control loop organization. Fast inner loops (e.g., implemented on FPGA, ASIC, analog circuitry, deterministic MCU, PLC, or RTOS) may handle laser pulse timing lock, pulse-to-position synchronization, scanner servo and phase loops, AOM or EOM gating, safety interlocks, mirror mount stabilization and laser beam correction using motorized mirrors, stage pathing, position, velocity, and acceleration control, and / or stage-to-scanner synchronization. Slow supervisory loops (e.g., implemented on CPU or GPU software) may handle recipe execution (e.g., printing pre-print structures to obtain calibration data), dose optimization (e.g., based on imaging data or environmental factors such as temperature, pressure, or age of patterning media), in-situ adaptation (e.g., dynamically adjusting patterning based on measured phase to compensate for errors via calculations or simulations such as ray-tracing, beam or wave propagation, FDTD, or electrical simulations), feature and fiducial registration (e.g., recognizing and aligning to printed or external fiducials), and / or spatiotemporal focus optimization and calibration (e.g., adjusting the temporal focusing system based on phase or fluorescence signals). Non-real-time supervisory software may manage recipes while deterministic hardware handles precise timing, though deterministic hardware may alternatively control all operations using lookup tables and precalculated patterning paths.IRRA-M05-PCT 4. Exemplary Variations

[0226] Hereafter are described different aspects of various variations of the systems and methods. These aspects are not intended to limit the systems and methods and do not include every variation and combination of variations described herein. Features which are described in the context of separate aspects and variations may be used together and / or be interchangeable. Similarly, features described in the context of a single variation may also be provided separately or in any suitable sub-combination.

[0227] Variation 1: A multi-photon lithography system comprising: an optical pulse source generating a pulsed light beam; line-forming optics receiving the pulsed light beam and producing a line-shaped beam having an elongated cross-section; a scanning system receiving the line-shaped beam and directing the line-shaped beam across a scan range; a digital mask system receiving the line-shaped beam from the scanning system, the digital mask system comprising an array of addressable elements modulating the line-shaped beam according to a spatial pattern; projection optics receiving modulated light from the digital mask system and projecting the modulated light toward a patterning plane; an objective lens receiving light from the projection optics and focusing the light onto the patterning plane within a substrate material; and a controller coordinating operation of the scanning system and the digital mask system to pattern the substrate material via multi-photon absorption.

[0228] Variation 2: A multi-photon lithography system comprising: an optical pulse source generating a pulsed light beam; line-forming optics receiving the pulsed light beam and producing a line-shaped beam having an elongated cross-section; a scanning system receiving the line-shaped beam and directing the line-shaped beam across a scan range; a digital mask system receiving the line-shaped beam from the scanning system, the digital mask system comprising a first digital micromirror device (DMD) and a second DMD, each comprising an array of addressable mirror elements, wherein the scanning system directs the line-shaped beam across the first DMD and the second DMD; projection optics receiving modulated light from the digital mask system and projecting the modulated light toward a patterning plane; an objective lens receiving light from the projection optics and focusing the light onto the patterning plane within aIRRA-M05-PCT substrate material; and a controller coordinating operation of the scanning system and the digital mask system to pattern the substrate material via multi-photon absorption.

[0229] Variation 3: A multi-photon lithography system comprising: an optical pulse source generating a pulsed light beam; line-forming optics receiving the pulsed light beam and producing a line-shaped beam having an elongated cross-section; a scanning system receiving the line-shaped beam and directing the line-shaped beam across a scan range; a digital mask system receiving the line-shaped beam from the scanning system, the digital mask system comprising an array of addressable elements modulating the line-shaped beam according to a spatial pattern; projection optics receiving modulated light from the digital mask system and projecting the modulated light toward a patterning plane; an objective lens receiving light from the projection optics and focusing the light onto the patterning plane within a substrate material; and a controller coordinating operation of the scanning system and the digital mask system to pattern the substrate material via multi-photon absorption; wherein the controller varies optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level.

[0230] Variation 4: A multi-photon lithography system comprising: an optical pulse source generating a pulsed light beam; line-forming optics receiving the pulsed light beam and producing a line-shaped beam having an elongated cross-section; a scanning system receiving the line-shaped beam and directing the line-shaped beam across a scan range; a digital mask system receiving the line-shaped beam from the scanning system, the digital mask system comprising an array of addressable elements modulating the line-shaped beam according to a spatial pattern; projection optics receiving modulated light from the digital mask system and projecting the modulated light toward a patterning plane; an objective lens receiving light from the projection optics and focusing the light onto the patterning plane within a substrate material; and a controller coordinating operation of the scanning system and the digital mask system to pattern the substrate material via multi-photon absorption; wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, the tiltIRRA-M05-PCT angle enabling patterning of a three-dimensional volume within the substrate material via lateral translation of the patterning plane relative to the substrate material.

[0231] Variation 7: A method for multi-photon lithography, comprising: generating a pulsed light beam from an optical pulse source; shaping the pulsed light beam into a line-shaped beam having an elongated cross-section; scanning the line-shaped beam across a digital mask system comprising an array of addressable elements; modulating the line-shaped beam via the digital mask system according to a spatial pattern; projecting modulated light from the digital mask system through projection optics and an objective lens to a patterning plane within a substrate material; and altering the substrate material at the patterning plane via multi-photon absorption.

[0232] Variation 8: A method for multi-photon lithography, comprising: generating a pulsed light beam from an optical pulse source; shaping the pulsed light beam into a line-shaped beam having an elongated cross-section; scanning the line-shaped beam across a digital mask system comprising a first digital micromirror device (DMD) and a second DMD, wherein scanning the line-shaped beam comprises directing the lineshaped beam to the first DMD during a first time period and directing the line-shaped beam to the second DMD during a second time period; modulating the line-shaped beam via the digital mask system according to a spatial pattern; projecting modulated light from the digital mask system through projection optics and an objective lens to a patterning plane within a substrate material; and altering the substrate material at the patterning plane via multi -photon absorption.

[0233] Variation 9: A method for multi-photon lithography, comprising: generating a pulsed light beam from an optical pulse source; shaping the pulsed light beam into a line-shaped beam having an elongated cross-section; scanning the line-shaped beam across a digital mask system comprising an array of addressable elements; modulating the line-shaped beam via the digital mask system according to a spatial pattern; projecting modulated light from the digital mask system through projection optics and an objective lens to a patterning plane within a substrate material; altering the substrate material at the patterning plane via multi-photon absorption; and varying optical exposure delivered to different voxels within the substrate material by coordinatingIRRA-M05-PCT patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level.

[0234] Variation 10: A method for multi-photon lithography, comprising: generating a pulsed light beam from an optical pulse source; shaping the pulsed light beam into a line-shaped beam having an elongated cross-section; scanning the line-shaped beam across a digital mask system comprising an array of addressable elements; modulating the line-shaped beam via the digital mask system according to a spatial pattern; projecting modulated light from the digital mask system through projection optics and an objective lens to a patterning plane within a substrate material, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material; altering the substrate material at the patterning plane via multi-photon absorption; and laterally translating the patterning plane relative to the substrate material to pattern a three-dimensional volume within the substrate material.

[0235] Variation 2.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the first DMD and the second DMD are tiled in an image plane such that their respective fields of view are adjacent, providing an enlarged total field of view.

[0236] Variation 2.2: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the scanning system alternates between directing the lineshaped beam to the first DMD and directing the line-shaped beam to the second DMD, such that one DMD patterns while the other DMD refreshes its pattern.

[0237] Variation 2.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a plurality of DMD sets, wherein each DMD set comprises multiple tiled DMDs, and wherein the scanning system switches between DMD sets.

[0238] Variation 2.4: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a knife-edge mirror combining modulated light from the first DMD and the second DMD into a common optical path.

[0239] Variation 2.5: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a concave mirror receiving modulated light fromIRRA-M05-PCT the first DMD and the second DMD at different angles and directing the modulated light along a common optical path.

[0240] Variation 2.6: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the scanning system comprises: a plurality of electro-optic modulators (EOMs), each EOM receiving a respective laser output and controlling polarization state of the respective laser output; a plurality of polarization beam splitters (PBSs) receiving light from the EOMs and directing light of a first polarization state to the first DMD and light of a second polarization state to the second DMD; and a combining polarization beam splitter receiving modulated light from the first DMD and the second DMD and directing the modulated light along a common optical path toward the objective lens; wherein the EOMs switch polarization states in a time-multiplexed fashion such that one DMD patterns while the other DMD refreshes.

[0241] Variation 2.7: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising at least a third DMD, wherein the scanning system directs the line-shaped beam sequentially to each of the first DMD, the second DMD, and the third DMD.

[0242] Variation 2.8: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the controller comprises an FPGA streaming pattern data to the first DMD and the second DMD at a sustained refresh rate of at least 10 kHz.

[0243] Variation 8.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the first DMD and the second DMD are tiled in an image plane such that their respective fields of view are adjacent.

[0244] Variation 8.2: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising refreshing a pattern on the first DMD while directing light to the second DMD for patterning.

[0245] Variation 8.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising switching between a plurality of DMD sets, wherein each DMD set comprises multiple tiled DMDs.

[0246] Variation 8.4: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein scanning the line-shaped beam comprises rotating a polygon scanner having multiple reflective faces, wherein rotation of the polygon scanner causesIRRA-M05-PCT different reflective faces to direct the line-shaped beam to the first DMD during the first time period and to the second DMD during the second time period.

[0247] Variation 3.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the controller coordinates N sweeps over a patterning field at binary- weighted power levels to achieve 2 N discrete exposure levels.

[0248] Variation 3.2: A variation of Variation 3.1 and / or any other variation herein, wherein N equals 3 and the binary- weighted power levels comprise 1 / 7, 2 / 7, and 4 / 7 of a maximum power level, achieving 8 discrete exposure levels.

[0249] Variation 3.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the projection optics are arranged such that an MxM array of pixels on the digital mask corresponds to a single diffraction-limited spot in the patterning plane, and wherein varying the number of active pixels within the MxM array varies the exposure level delivered to the diffraction-limited spot.

[0250] Variation 3.4: A variation of Variation 3.3 and / or any other variation herein, wherein M is 2, 3, or 4, providing up to 4, 9, or 16 discrete exposure levels respectively.

[0251] Variation 3.5: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a power modulation element in the optical path between the optical pulse source and the digital mask system, the power modulation element comprising an electro-optic modulator (EOM) or an acousto-optic modulator (AOM), and wherein the controller adjusts power level via the power modulation element for each sweep.

[0252] Variation 3.6: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the controller comprises a lookup table correlating exposure parameters to resulting exposure levels in the substrate material.

[0253] Variation 3.7: A variation of Variation 3.6 and / or any other variation herein, wherein the lookup table compensates for nonlinearities in exposure response of the substrate material.

[0254] Variation 9.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein coordinating patterning comprises performing N sweeps over a patterning field at binary- weighted power levels to achieve 2AN discrete exposure levels.IRRA-M05-PCT

[0255] Variation 9.2: A variation of Variation 9.1 and / or any other variation herein, wherein N equals 3 and the binary- weighted power levels comprise 1 / 7, 2 / 7, and 4 / 7 of a maximum power level, achieving 8 discrete exposure levels.

[0256] Variation 9.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein an MxM array of pixels on the digital mask corresponds to a single diffraction-limited spot in the patterning plane, and wherein varying the number of active pixels within the MxM array varies the exposure level delivered to the diffraction-limited spot.

[0257] Variation 9.4: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising modulating power of the pulsed light beam via an electro-optic modulator (EOM) or an acousto-optic modulator (AOM) for each sweep.

[0258] Variation 9.5: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising calibrating exposure parameters using a lookup table correlating exposure parameters to resulting exposure levels.

[0259] Variation 4.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the three-dimensional volume within the substrate material spans multiple Z-depths during the lateral translation, the thickness of the volume being greater than an axial resolution of a single voxel.

[0260] Variation 4.2: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a tilted mirror for remote focal plane manipulation, tilted with respect to an optical axis to establish the tilted patterning plane.

[0261] Variation 4.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a phase plate in an optical path between the digital mask and the objective lens, the phase plate establishing the tilted patterning plane.

[0262] Variation 4.4: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein an optical axis of the objective lens is rotated with respect to the XY plane of the substrate material.

[0263] Variation 4.5: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a stage supporting the substrate material and providing continuous motion for the lateral translation.IRRA-M05-PCT

[0264] Variation 4.6: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a remote focal plane manipulation system repositioning the patterning plane along an axial direction without moving the objective lens or the substrate material.

[0265] Variation 10.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the three-dimensional volume within the substrate material spans multiple Z-depths during the lateral translation, the thickness of the volume being greater than an axial resolution of a single voxel.

[0266] Variation 10.2: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein laterally translating comprises continuous translation.

[0267] Variation 10.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising repositioning the patterning plane along an axial direction via remote focal plane manipulation without moving the objective lens or the substrate material.

[0268] Variation 5.2: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the scanning system comprises a polygon scanner having multiple reflective faces.

[0269] Variation 5.2.1: A variation of Variation 5.2 and / or any other variation herein, further comprising a plurality of polygon scanners arranged in parallel or in series.

[0270] Variation 5.2.2: A variation of Variation 5.2.1 and / or any other variation herein, wherein the plurality of polygon scanners is operated in-phase or out-of-phase to reduce dead time at polygon face transitions.

[0271] Variation 11.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein scanning the line-shaped beam across the digital mask system comprises directing the line-shaped beam via a rotating polygon scanner having multiple reflective faces.

[0272] Variation 11.1.1: A variation of Variation 11.1 and / or any other variation herein, wherein directing the line-shaped beam comprises using a plurality of polygon scanners arranged in parallel or in series.IRRA-M05-PCT

[0273] Variation 11.1.2: A variation of Variation 11.1.1 and / or any other variation herein, wherein the plurality of polygon scanners is operated in-phase or out-of-phase to reduce dead time at polygon face transitions.

[0274] Variation 5.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the line-shaped beam forms a focal line tilted greater than 30 degrees with respect to a scan direction, the focal line aligned with a pixel array axis of the digital mask for operation in a blazed grating condition.

[0275] Variation 5.3.1: A variation of Variation 5.3 and / or any other variation herein, further comprising a phase plate compensating for focal distance variation along the tilted focal line.

[0276] Variation 5.3.2: A variation of Variation 5.3 and / or any other variation herein, wherein the line-forming optics comprise a cylindrical lens element having varying focal length along the focal line.

[0277] Variation 11.2: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the line-shaped beam forms a focal line tilted greater than 30 degrees with respect to a scan direction, the focal line aligned with a pixel array axis of the digital mask for operation in a blazed grating condition.

[0278] Variation 5.4: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: a spatial light modulator in a beam path between the optical pulse source and the digital mask system; a sensor measuring a beam profile of the line-shaped beam; and a feedback controller coupling the sensor to the spatial light modulator and adjusting the spatial light modulator to correct for aberrations during scanning.

[0279] Variation 11.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: measuring a beam profile of the line-shaped beam; adjusting a spatial light modulator based on the measured beam profile to correct for aberrations; and repeating the measuring and adjusting during scanning.

[0280] Variation 5.5: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: a stage supporting the substrate material; and a position feedback system measuring a position of the stage; wherein the controllerIRRA-M05-PCT adjusts a location of the projected modulated light within the substrate material based on the measured position.

[0281] Variation 5.5.1: A variation of Variation 5.5 and / or any other variation herein, wherein the position feedback system measures fluorescence from previously patterned locations within the substrate material.

[0282] Variation 11.4: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: measuring a position of a stage supporting the substrate material; and adjusting a location of the projected modulated light within the substrate material based on the measured position.

[0283] Variation 11.4.1: A variation of Variation 11.4 and / or any other variation herein, wherein measuring comprises detecting fluorescence from previously patterned locations within the substrate material.

[0284] Variation 5.6: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: a phase measurement subsystem measuring optical path length through the substrate material after each patterning pass; wherein the controller determines a phase profile of each patterned region by subtracting successive optical path length measurements.

[0285] Variation 11.5: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: measuring optical path length through the substrate material after each patterning pass; and determining a phase profile of each patterned region by subtracting successive optical path length measurements.

[0286] Variation 5.7: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: a beam splitter splitting the pulsed light beam into a first portion and a second portion; and an optical delay line delaying the second portion relative to the first portion, increasing an effective repetition rate of optical pulses delivered to the substrate material.

[0287] Variation 11.6: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: splitting the pulsed light beam into a first portion and a second portion; delaying the second portion relative to the first portion via an optical delay line; and recombining the first and second portions to increase an effective repetition rate.IRRA-M05-PCT

[0288] Variation 5.11: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a partially silvered mirror in an imaging path.

[0289] Variation 5.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the substrate material comprises chromophore dye molecules that locally bind within the substrate material upon multi-photon absorption.

[0290] Variation 5.8: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a stage supporting the substrate material and providing motion along an angular axis, a radial axis, and an axial Z axis for patterning cylindrical geometries.

[0291] Variation 5.9: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising a stage supporting the substrate material and providing motion along six axes for patterning arbitrary geometries.

[0292] Variation 11.7: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising scanning along an angular axis, a radial axis, and an axial Z axis for patterning cylindrical geometries within the substrate material.

[0293] Variation 5.10: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising an imaging system registering patterning location to existing structures on or within the substrate material.

[0294] Variation 5.10.1: A variation of Variation 5.10 and / or any other variation herein, wherein the imaging system shares an optical path with the projection optics and the objective lens via a dichroic element.

[0295] Variation 11.8: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising: imaging existing structures on or within the substrate material; and aligning patterning location to the existing structures.

[0296] Variation 11.8.1: A variation of Variation 11.8 and / or any other variation herein, wherein imaging is performed in-situ during patterning via a shared optical path with the patterning optics.

[0297] Variation 5.12: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the controller comprises a clock input configured as a synchronization source, the clock input receiving a timing signal derived from one of theIRRA-M05-PCT optical pulse source, the scanning system, the digital mask system, or a stage supporting the substrate material.

[0298] Variation 5.12.1: A variation of Variation 5.12 and / or any other variation herein, wherein the controller comprises one or more phase-locked loops (PLLs) aligning timing, phase, or frequency of subsystems to the timing signal.

[0299] Variation 5.12.2: A variation of Variation 5.12 and / or any other variation herein, wherein the timing signal is derived from the scanning system.

[0300] Variation 5.12.3: A variation of Variation 5.12.2 and / or any other variation herein, further comprising a synchronization light source and a photodetector positioned to detect a reference point on the scanning system, the photodetector generating the timing signal received by the clock input.

[0301] Variation 11.9: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising synchronizing the optical pulse source, the scanning system, and the digital mask system using a primary timing reference derived from one of the optical pulse source, the scanning system, the digital mask system, or a stage supporting the substrate material.

[0302] Variation 11.9.1: A variation of Variation 11.9 and / or any other variation herein, wherein synchronizing comprises aligning timing, phase, or frequency of subsystems using one or more phase-locked loops.

[0303] Variation 11.9.2: A variation of Variation 11.9 and / or any other variation herein, further comprising monitoring a position or phase of the scanning system, wherein the primary timing reference is derived from the monitoring.

[0304] Variation 6.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the digital mask system comprises a first digital micromirror device (DMD) and a second DMD, and wherein the controller varies optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level.

[0305] Variation 6.2: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the digital mask system comprises a first digital micromirror device (DMD) and a second DMD, and wherein the patterning plane is oriented at a tiltIRRA-M05-PCT angle with respect to an XY plane of the substrate material, the tilt angle enabling patterning of a three-dimensional volume within the substrate material via lateral translation of the patterning plane relative to the substrate material.

[0306] Variation 6.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the controller varies optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels, and wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, the tilt angle enabling patterning of a three-dimensional volume within the substrate material via lateral translation of the patterning plane relative to the substrate material.

[0307] Variation 6.4: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the digital mask system comprises a first digital micromirror device (DMD) and a second DMD; wherein the controller varies optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level; and wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material.

[0308] Variation 12.1: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the digital mask system comprises a first digital micromirror device (DMD) and a second DMD, and further comprising varying optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level.

[0309] Variation 12.2: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the digital mask system comprises a first digital micromirror device (DMD) and a second DMD, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, and further comprising laterally translating the patterning plane relative to the substrate material to pattern a three-dimensional volume within the substrate material.IRRA-M05-PCT

[0310] Variation 12.3: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, further comprising varying optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, and further comprising laterally translating the patterning plane relative to the substrate material to pattern a three-dimensional volume within the substrate material.

[0311] Variation 12.4: A variation of Variations 1, 2, 3, 4, 7, 8, 9, 10, and / or any other variation herein, wherein the digital mask system comprises a first digital micromirror device (DMD) and a second DMD; further comprising varying optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level; and further comprising laterally translating the patterning plane relative to the substrate material, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, to pattern a three-dimensional volume.

[0312] As used herein, first, second, third, etc. are used to characterize and distinguish various elements, components, regions, layers and / or sections. These elements, components, regions, layers and / or sections should not be limited by these terms. Use of numerical terms maybe used to distinguish one element, component, region, layer and / or section from another element, component, region, layer and / or section. Use of such numerical terms does not imply a sequence or order unless clearly indicated by the context. Such numerical references may be used interchangeable without departing from the teaching of the embodiments and variations herein.

[0313] As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the embodiments of the invention without departing from the scope of this invention as defined in the following claims.

Claims

IRRA-M05-PCT CLAIMSWe Claim:

1. A multi-photon lithography system comprising:an optical pulse source generating a pulsed light beam;line-forming optics receiving the pulsed light beam and producing a line-shaped beam having an elongated cross-section;a scanning system receiving the line-shaped beam and directing the line-shaped beam across a scan range;a digital mask system receiving the line-shaped beam from the scanning system, the digital mask system comprising an array of addressable elements modulating the line-shaped beam according to a spatial pattern; projection optics receiving modulated light from the digital mask system and projecting the modulated light toward a patterning plane;an objective lens receiving light from the projection optics and focusing the light onto the patterning plane within a substrate material; anda controller coordinating operation of the scanning system and the digital mask system to pattern the substrate material via multi-photon absorption.

2. The system of claim 1, wherein the digital mask system comprises a first digital micromirror device (DMD) and a second DMD, each comprising an array of addressable mirror elements, and wherein the scanning system directs the lineshaped beam across the first DMD and the second DMD.

3. The system of claim 2, wherein the first DMD and the second DMD are tiled in an image plane such that their respective fields of view are adjacent, providing an enlarged total field of view.

4. The system of claim 2, wherein the scanning system alternates between directing the line-shaped beam to the first DMD and directing the line-shaped beam to the second DMD, such that one DMD patterns while the other DMD refreshes its pattern.IRRA-M05-PCT 5. The system of claim 2, further comprising a plurality of DMD sets, wherein each DMD set comprises multiple tiled DMDs, and wherein the scanning system switches between DMD sets.

6. The system of claim 2, further comprising a knife-edge mirror combining modulated light from the first DMD and the second DMD into a common optical path.

7. The system of claim 2, further comprising a concave mirror receiving modulated light from the first DMD and the second DMD at different angles and directing the modulated light along a common optical path.

8. The system of claim 2, wherein the scanning system comprises:a plurality of electro-optic modulators (EOMs), each EOM receiving a respective laser output and controlling polarization state of the respective laser output; a plurality of polarization beam splitters (PBSs) receiving light from the EOMs and directing light of a first polarization state to the first DMD and light of a second polarization state to the second DMD; anda combining polarization beam splitter receiving modulated light from the first DMD and the second DMD and directing the modulated light along a common optical path toward the objective lens;wherein the EOMs switch polarization states in a time-multiplexed fashion such that one DMD patterns while the other DMD refreshes.

9. The system of claim 2, further comprising at least a third DMD, wherein the scanning system directs the line-shaped beam sequentially to each of the first DMD, the second DMD, and the third DMD.

10. The system of claim 2, wherein the controller comprises an FPGA streaming pattern data to the first DMD and the second DMD at a sustained refresh rate of at least 10 kHz.

11. The system of claim 1, wherein the controller varies optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level.IRRA-M05-PCT 12. The system of claim n, wherein the controller coordinates N sweeps over a patterning field at binary- weighted power levels to achieve 2AN discrete exposure levels.

13. The system of claim 12, wherein N equals 3 and the binary-weighted power levels comprise 1 / 7, 2 / 7, and 4 / 7 of a maximum power level, achieving 8 discrete exposure levels.

14. The system of claim 11, wherein the projection optics are arranged such that an MxM array of pixels on the digital mask corresponds to a single diffractionlimited spot in the patterning plane, and wherein varying the number of active pixels within the MxM array varies the exposure level delivered to the diffraction-limited spot.

15. The system of claim 14, wherein M is 2, 3, or 4, providing up to 4, 9, or 16 discrete exposure levels respectively.

16. The system of claim 11, further comprising a power modulation element in the optical path between the optical pulse source and the digital mask system, the power modulation element comprising an electro-optic modulator (EOM) or an acousto-optic modulator (AOM), and wherein the controller adjusts power level via the power modulation element for each sweep.

17. The system of claim 11, wherein the controller comprises a lookup table correlating exposure parameters to resulting exposure levels in the substrate material.

18. The system of claim 17, wherein the lookup table compensates for nonlinearities in exposure response of the substrate material.

19. The system of claim 1, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, the tilt angle enabling patterning of a three-dimensional volume within the substrate material via lateral translation of the patterning plane relative to the substrate material.

20. The system of claim 19, wherein the three-dimensional volume within the substrate material spans multiple Z-depths during the lateral translation, the thickness of the volume being greater than an axial resolution of a single voxel.IRRA-M05-PCT 21. The system of claim 19, further comprising a tilted mirror for remote focal plane manipulation tilted with respect to an optical axis to establish the tilted patterning plane.

22. The system of claim 19, further comprising a phase plate in an optical path between the digital mask and the objective lens, the phase plate establishing the tilted patterning plane.

23. The system of claim 19, wherein an optical axis of the objective lens is rotated with respect to the XY plane of the substrate material.

24. The system of claim 19, further comprising a stage supporting the substrate material and providing continuous motion for the lateral translation.

25. The system of claim 19, further comprising a remote focal plane manipulation system repositioning the patterning plane along an axial direction without moving the objective lens or the substrate material.

26. The system of claim 1, wherein the substrate material comprises chromophore dye molecules that locally bind within the substrate material upon multi -photon absorption.

27. The system of claim 1, wherein the scanning system comprises a polygon scanner having multiple reflective faces.

28. The system of claim 27, further comprising a plurality of polygon scanners arranged in parallel or in series.

29. The system of claim 28, wherein the plurality of polygon scanners is operated in- phase or out-of-phase to reduce dead time at polygon face transitions.

30. The system of claim 1, wherein the line-shaped beam forms a focal line tilted greater than 30 degrees with respect to a scan direction, the focal line aligned with a pixel array axis of the digital mask for operation in a blazed grating condition.

31. The system of claim 30, further comprising a phase plate compensating for focal distance variation along the tilted focal line.

32. The system of claim 30, wherein the line-forming optics comprise a cylindrical lens element having varying focal length along the focal line.

33. The system of claim 1, further comprising:IRRA-M05-PCT a spatial light modulator in a beam path between the optical pulse source and the digital mask system;a sensor measuring a beam profile of the line-shaped beam; anda feedback controller coupling the sensor to the spatial light modulator and adjusting the spatial light modulator to correct for aberrations during scanning.

34. The system of claim 1, further comprising:a stage supporting the substrate material; anda position feedback system measuring a position of the stage;wherein the controller adjusts a location of the projected modulated light within the substrate material based on the measured position.

35. The system of claim 34, wherein the position feedback system measures fluorescence from previously patterned locations within the substrate material.

36. The system of claim 1, further comprising:a phase measurement subsystem measuring optical path length through the substrate material after each patterning pass;wherein the controller determines a phase profile of each patterned region by subtracting successive optical path length measurements.

37. The system of claim 1, further comprising:a beam splitter splitting the pulsed light beam into a first portion and a second portion; andan optical delay line delaying the second portion relative to the first portion, increasing an effective repetition rate of optical pulses delivered to the substrate material.

38. The system of claim 1, further comprising a stage supporting the substrate material and providing motion along an angular axis, a radial axis, and an axial Z axis for patterning cylindrical geometries.

39. The system of claim 1, further comprising a stage supporting the substrate material and providing motion along six axes for patterning arbitrary geometries.IRRA-M05-PCT 40. The system of claim 1, further comprising an imaging system registering patterning location to existing structures on or within the substrate material.

41. The system of claim 40, wherein the imaging system shares an optical path with the projection optics and the objective lens via a dichroic element.

42. The system of claim 1, further comprising a partially silvered mirror in an imaging path.

43. The system of claim 1, wherein the controller comprises a clock input configured as a synchronization source, the clock input receiving a timing signal derived from one of the optical pulse source, the scanning system, the digital mask system, or a stage supporting the substrate material.

44. The system of claim 43, wherein the controller comprises one or more phase- locked loops (PLLs) aligning timing, phase, or frequency of subsystems to the timing signal.

45. The system of claim 43, wherein the timing signal is derived from the scanning system.

46. The system of claim 45, further comprising a synchronization light source and a photodetector positioned to detect a reference point on the scanning system, the photodetector generating the timing signal received by the clock input.

47. The system of any of claims 2-10, wherein the controller varies optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level.

48. The system of any of claims 2-10, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, the tilt angle enabling patterning of a three-dimensional volume within the substrate material via lateral translation of the patterning plane relative to the substrate material.

49. The system of any of claims 11-18, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, the tilt angle enabling patterning of a three-dimensional volume within the substrate material via lateral translation of the patterning plane relative to the substrate material.IRRA-M05-PCT 50. The system of claim 2, wherein:the controller varies optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level; andthe patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material.

51. A method for multi-photon lithography, comprising:generating a pulsed light beam from an optical pulse source;shaping the pulsed light beam into a line-shaped beam having an elongated cross-section;scanning the line-shaped beam across a digital mask system comprising an array of addressable elements;modulating the line-shaped beam via the digital mask system according to a spatial pattern;projecting modulated light from the digital mask system through projection optics and an objective lens to a patterning plane within a substrate material; andaltering the substrate material at the patterning plane via multi-photon absorption.

52. The method of claim 51, wherein the digital mask system comprises a first digital micromirror device (DMD) and a second DMD, and wherein scanning the lineshaped beam across the digital mask system comprises:directing the line-shaped beam to the first DMD during a first time period; and directing the line-shaped beam to the second DMD during a second time period.

53. The method of claim 52, wherein the first DMD and the second DMD are tiled in an image plane such that their respective fields of view are adjacent.

54. The method of claim 52, further comprising refreshing a pattern on the first DMD while directing light to the second DMD for patterning.IRRA-M05-PCT 55- The method of claim 52, further comprising switching between a plurality of DMD sets, wherein each DMD set comprises multiple tiled DMDs.

56. The method of claim 52, wherein scanning the line-shaped beam comprises rotating a polygon scanner having multiple reflective faces, wherein rotation of the polygon scanner causes different reflective faces to direct the line-shaped beam to the first DMD during the first time period and to the second DMD during the second time period.

57. The method of claim 51, further comprising varying optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level.

58. The method of claim 57, wherein coordinating patterning comprises performing N sweeps over a patterning field at binary- weighted power levels to achieve 2AN discrete exposure levels.

59. The method of claim 58, wherein N equals 3 and the binary- weighted power levels comprise 1 / 7, 2 / 7, and 4 / 7 of a maximum power level, achieving 8 discrete exposure levels.

60. The method of claim 57, wherein an MxM array of pixels on the digital mask corresponds to a single diffraction-limited spot in the patterning plane, and wherein varying the number of active pixels within the MxM array varies the exposure level delivered to the diffraction-limited spot.

61. The method of claim 57, further comprising modulating power of the pulsed light beam via an electro-optic modulator (EOM) or an acousto-optic modulator (AOM) for each sweep.

62. The method of claim 57, further comprising calibrating exposure parameters using a lookup table correlating exposure parameters to resulting exposure levels.

63. The method of claim 51, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, and further comprising: laterally translating the patterning plane relative to the substrate material to pattern a three-dimensional volume within the substrate material.IRRA-M05-PCT 64. The method of claim 63, wherein the three-dimensional volume within the substrate material spans multiple Z-depths during the lateral translation, the thickness of the volume being greater than an axial resolution of a single voxel.

65. The method of claim 63, wherein laterally translating comprises continuous translation.

66. The method of claim 63, further comprising repositioning the patterning plane along an axial direction via remote focal plane manipulation without moving the objective lens or the substrate material.

67. The method of claim 51, wherein scanning the line-shaped beam across the digital mask system comprises directing the line-shaped beam via a rotating polygon scanner having multiple reflective faces.

68. The method of claim 67, wherein directing the line-shaped beam comprises using a plurality of polygon scanners arranged in parallel or in series.

69. The method of claim 68, wherein the plurality of polygon scanners is operated in- phase or out-of-phase to reduce dead time at polygon face transitions.

70. The method of claim 51, wherein the line-shaped beam forms a focal line tilted greater than 30 degrees with respect to a scan direction, the focal line aligned with a pixel array axis of the digital mask for operation in a blazed grating condition.

71. The method of claim 51, further comprising:measuring a beam profile of the line-shaped beam;adjusting a spatial light modulator based on the measured beam profile to correct for aberrations; andrepeating the measuring and adjusting during scanning.

72. The method of claim 51, further comprising:measuring a position of a stage supporting the substrate material; and adjusting a location of the projected modulated light within the substrate material based on the measured position.

73. The method of claim 72, wherein measuring comprises detecting fluorescence from previously patterned locations within the substrate material.IRRA-M05-PCT 74- The method of claim 51, further comprising:measuring optical path length through the substrate material after each patterning pass; anddetermining a phase profile of each patterned region by subtracting successive optical path length measurements.

75. The method of claim 51, further comprising:splitting the pulsed light beam into a first portion and a second portion; delaying the second portion relative to the first portion via an optical delay line;andrecombining the first and second portions to increase an effective repetition rate.

76. The method of claim 51, further comprising scanning along an angular axis, a radial axis, and an axial Z axis for patterning cylindrical geometries within the substrate material.

77. The method of claim 51, further comprising:imaging existing structures on or within the substrate material; andaligning patterning location to the existing structures.

78. The method of claim 77, wherein imaging is performed in-situ during patterning via a shared optical path with the patterning optics.

79. The method of claim 51, further comprising synchronizing the optical pulse source, the scanning system, and the digital mask system using a primary timing reference derived from one of the optical pulse source, the scanning system, the digital mask system, or a stage supporting the substrate material.

80. The method of claim 79, wherein synchronizing comprises aligning timing, phase, or frequency of subsystems using one or more phase-locked loops.

81. The method of claim 79, further comprising monitoring a position or phase of the scanning system, wherein the primary timing reference is derived from the monitoring.

82. The method of any of claims 52-56, further comprising varying optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposureIRRA-M05-PCT levels spanning a range from a minimum exposure level to a maximum exposure level.

83. The method of any of claims 52-56, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, and further comprising laterally translating the patterning plane relative to the substrate material to pattern a three-dimensional volume within the substrate material.

84. The method of any of claims 57-62, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, and further comprising laterally translating the patterning plane relative to the substrate material to pattern a three-dimensional volume within the substrate material.

85. The method of claim 52, further comprising:varying optical exposure delivered to different voxels within the substrate material by coordinating patterning across one or more sweeps to produce a plurality of discrete exposure levels spanning a range from a minimum exposure level to a maximum exposure level; andlaterally translating the patterning plane relative to the substrate material, wherein the patterning plane is oriented at a tilt angle with respect to an XY plane of the substrate material, to pattern a three-dimensional volume.

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