Controlling light source wavelengths to achieve selectable phase shifts between pixels in digital lithography system

Abstract

A digital lithography system may adjust a wavelength of a light source to compensate for tilt errors of a micromirror while maintaining a vertical direction of reflected light. Adjacent pixels may have a phase shift, which is determined by the optical path difference between the respective beams of the pixels. This phase shift may be preselected to any value by generating a corresponding wavelength at the light source based on the optical path difference. To produce a particular wavelength corresponding to the desired phase shift, the light source may produce a plurality of light components having wavelengths surrounding the wavelength of the selected phase shift. The intensities of these components may then be individually controlled to produce an effect on the substrate that approximates the selected phase shift.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. non-provisional patent application No. 17 / 750,751, filed on May 23, 2022, entitled “CONTROLLINGLIGHT SOURCE WAVELENGTHS FOR SELECTABLE PHASE SHIFTS BETWEEN PIXELS INDIGITAL LITHOGRAPHY SYSTEMS,” which is incorporated herein by reference. Technical Field

[0003] The present disclosure generally describes a method of producing a preselected phase shift between pixels in a digital lithography system. More specifically, the present disclosure describes the effect of controlling the wavelength output of a light source during a lithography process to produce or approximate a preselected phase shift on a substrate. Background Art

[0004] Spatial light modulators are often used to apply spatially varying modulation to a light beam. A digital micromirror device (DMD), an example of a spatial light modulator, is used as a reflective digital optical switch in a variety of applications, including digital lithography. For digital lithography, a DMD is typically combined with other image processing components, such as memory, light source, and optical elements, and used to project a desired pattern onto a photosensitive material on a substrate being processed.

[0005] A DMD typically includes hundreds of thousands of microscopic mirrors ("micromirrors") arranged in a rectangular array. Each micromirror corresponds to a single pixel of the image to be displayed and can be tilted at various angles around a hinge. Depending on the tilt angle of the micromirror, the micromirror is in an "on" or "off" state. In the on state, light is reflected from the DMD into the lens, and ultimately a pixel is projected brightly onto the substrate. In the off state, light is directed elsewhere (such as a light dump), and the projected pixel appears dark.

[0006] The phase shift between adjacent micromirrors of a DMD affects the resolution and depth of focus of the projected image. Generally speaking, the phase shift between adjacent micromirrors of a DMD is 0 degrees. A DMD with a 0 degree phase shift between adjacent micromirrors is called a blazed DMD. Although blazed DMDs exhibit good resolution and depth of focus, as device sizes become smaller and smaller, improved resolution and better depth of focus are needed, especially for line spacing. In mask-based lithography, hard phase-shift masks have been used to print very narrow and dark lines. However, hard phase-shift masks are limited by the topology of the design.

[0007] Therefore, there is a need in the art for an improved spatial light modulator with improved image resolution and focus depth, and a digital lithography method using the spatial light modulator. Summary of the invention

[0008] In some embodiments, a digital lithography system may include: a first spatial light modulator pixel configured to direct a first light beam onto a substrate during a digital lithography process; a second spatial light modulator pixel configured to direct a second light beam onto the substrate during the digital lithography process; and a light source configured to generate the first light beam. The first light beam may include multiple components, including: a first component having a first wavelength that produces a first phase shift greater than a preselected phase shift; and a second component having a second wavelength that produces a second phase shift less than the preselected phase shift. The digital lithography system may include: a controller configured to control the intensities of the multiple components to produce an effect on the substrate that approximates the preselected phase shift.

[0009] In some embodiments, a method of adjusting a phase shift between pixels in a digital lithography system may include: projecting a first light beam onto a first spatial light modulator pixel. The first spatial light modulator pixel may direct the first light beam onto a substrate during a digital lithography process. The first light beam may include multiple components, the multiple components including: a first component having a first wavelength, the first wavelength producing a first phase shift greater than a preselected phase shift; and a second component having a second wavelength, the second wavelength producing a second phase shift less than the preselected phase shift. The method may also include: projecting a second light beam onto a second spatial light modulator pixel. The second spatial light modulator pixel may direct the second light beam onto the substrate during the digital lithography process. The method may also include: controlling the intensity of the multiple components to produce an effect on the substrate that approximates the preselected phase shift.

[0010] In some embodiments, a method for adjusting or selecting a phase shift between pixels in a digital lithography system may include: projecting a first light beam onto a first spatial light modulator pixel. The first spatial light modulator pixel may direct the first light beam onto a substrate during a digital lithography process. The method may also include: projecting a second light beam onto a second spatial light modulator pixel. The second spatial light modulator pixel may direct the second light beam onto the substrate during the digital lithography process. The second spatial light modulator pixel may be adjacent to the first spatial light modulator pixel in a spatial light modulator pixel array. The method may also include: controlling the wavelength of the first light beam and / or the wavelength of the second light beam based on an optical path difference between the first light beam and the second light beam to produce a preselected phase shift between the first light beam and the second light beam on the substrate.

[0011] In any embodiment, any and all of the following features may be implemented in any combination and without limitation. The second spatial light modulator pixel may be adjacent to the first spatial light modulator pixel in a spatial light modulator pixel array in a digital micromirror device. The first spatial light modulator pixel may include a micromirror that adjusts between an open position and a closed position, the open position reflecting light onto the substrate and the closed position reflecting light away from the substrate. The light source may also be configured to generate the second light beam such that the first light beam and the second light beam originate from the light source. The second light beam may be generated from a different light source, and the controller may be further configured to control the intensity of a component in the second light beam to correct a tilt error of the second spatial light modulator pixel that is different from the tilt error of the first spatial light modulator pixel. The light source may include multiple groups of laser diodes. A first subset of the multiple groups of laser diodes may be configured to output approximately the first wavelength, and a second subset of the multiple groups of laser diodes may be configured to output approximately the second wavelength. The light source may include a homogenizing rod that mixes the first component with the second component to produce a uniform first light beam. In addition to the first component and the second component, the multiple components may also include multiple additional components. The first wavelength may produce a first phase shift that is approximately 20° greater than the preselected phase shift. The second wavelength may produce a second phase shift that is approximately 10° less than the preselected phase shift. The preselected phase shift may be selected as any phase shift between 0° and 359°. The step of controlling the intensity of the multiple components may include: calculating a weight in a linear combination of the deviations of the first phase shift and the second phase shift relative to the preselected phase shift for each of the multiple components, so that the linear combination is approximately zero. The weights in the linear combination may correspond to the intensities of the multiple components. The step of approximating the preselected phase shift may produce a light intensity pattern on the substrate that approximates a light intensity pattern that would appear on the substrate if a single wavelength corresponding to the preselected phase shift was used. The first phase shift may be calculated based on the first wavelength and the optical path difference between the first light beam and the second light beam. The second spatial light modulator pixel may be adjacent to the first spatial light modulator pixel in a spatial light modulator pixel array in a digital micromirror device, and the second light beam may also include the first component and the second component. The step of controlling the wavelength of the first light beam may include: switching between different laser diodes that produce light with different wavelengths. The step of controlling the wavelength of the first light beam may include: changing the wavelength of the first light beam by controlling the temperature of the light source, mechanically changing the cavity of the light source, or electroacoustically changing the cavity of the light source.

[0012] BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The nature and advantages of the various embodiments may be further understood by reference to the remainder of this specification and the accompanying drawings, wherein like reference numerals are used to refer to like components throughout the several drawings. In some cases, a sub-label is associated with a reference numeral to indicate one of a plurality of similar components. When a reference numeral is mentioned without specifying the presence of a sub-label, it is intended to refer to all such plurality of similar components.

[0014] Figure 1 is a perspective view of a system for digital lithography, according to some embodiments.

[0015] Figure 2 A perspective schematic diagram of an image projection system of the system according to some embodiments is shown.

[0016] Figure 3 A digital micromirror device (DMD) is shown in accordance with some embodiments.

[0017] Figure 4A A pair of adjacent micromirrors is shown directing a light beam toward a substrate in accordance with some embodiments.

[0018] Figure 4B Adjacent micromirrors are shown, wherein the tilt angle is different from the ideal tilt angle, according to some embodiments.

[0019] Figure 4C It shows how, according to some embodiments, changes in tilt angle can be accounted for by changing the angle of the light beam.

[0020] Figure 5 It is shown how the optical path difference (OPD) between two adjacent micromirrors can cause a phase shift on a substrate according to some embodiments.

[0021] Figure 6 A system for adjusting phase shifts between pixels in a digital lithography system is shown in accordance with some embodiments.

[0022] Figure 7 A flow chart of a method for adjusting or selecting a phase shift between pixels in a digital lithography system is shown, in accordance with some embodiments.

[0023] Figure 8 A light source that can be used in a photolithography system according to some embodiments is shown.

[0024] Fig. 9 A system for using a light beam having multiple wavelengths surrounding a preselected wavelength is shown in accordance with some embodiments.

[0025] Fig.10 A graph showing the effect of using a light beam having multiple light components surrounding a preselected phase shift according to some embodiments.

[0026] Fig.11 A graph is shown illustrating how multiple components can be used to approximate and tune any preselected wavelength, in accordance with some embodiments.

[0027] Fig.12 A flow chart illustrating a method of selecting or adjusting a phase shift between pixels in a digital lithography system, according to some embodiments.

[0028] Fig.13 An exemplary computer system is shown in which various embodiments may be implemented. DETAILED DESCRIPTION

[0029] Figure 1 1 is a perspective view of a system 100 for digital lithography according to some embodiments. The system 100 may include a base frame 110, a slab 120, one or more platforms 130 (two are shown as an example), and / or a handling device 160. The base frame 110 may rest on the floor of a manufacturing facility and support the slab 120. A passive air isolator 112 may be positioned between the base frame 110 and the slab 120. In some embodiments, the slab 120 may include a single block of granite, and the one or more platforms 130 may be disposed on the slab 120. A substrate 140 may be supported by each of the one or more platforms 130. A plurality of holes (not shown) may be formed in the one or more platforms 130 to allow a plurality of lift pins (not shown) to extend therethrough. The lift pins may be raised to an extended position to receive the substrate 140, such as from one or more transfer robots (not shown). The one or more transfer robots may be used to load and unload the substrate 140 from the one or more platforms 130.

[0030] Substrate 140 can be made of glass, for example, and used as a part of a flat panel display. In some embodiments, substrate 140 can be made of other materials. In some embodiments, substrate 140 can have a photoresist layer formed thereon. The photoresist can be sensitive to radiation, and can include a positive photoresist or a negative photoresist, meaning that the portion of the photoresist exposed to radiation can be soluble or insoluble in the photoresist developer applied to the photoresist after the pattern is written into the photoresist. The chemical composition of the photoresist can determine whether the photoresist is a positive photoresist or a negative photoresist. For example, the photoresist can include at least one of diazonaphthoquinone, phenol formaldehyde resin, poly (methyl methacrylate), poly (methyl glutarimide) and / or SU-8. In this way, a pattern can be created on the surface of substrate 140 to form an electronic circuit system.

[0031] The system 100 may further include a pair of supports 122 and a pair of tracks 124. The pair of supports 122 may be disposed on the flat plate 120, and the flat plate 120 and the pair of supports 122 may be formed as a single block of material. The pair of tracks 124 may be supported by the pair of supports 122, and the one or more platforms 130 may move in the X direction along the tracks 124. In some embodiments, the pair of tracks 124 may include a pair of parallel magnetic channels. As shown, each track 124 in the pair of tracks 124 may be linear. In some embodiments, the track 124 may have a non-linear shape. An encoder 126 may be coupled to each of the one or more platforms 130 to provide position information to a controller (not shown).

[0032] The processing device 160 may include a support 162 and / or a processing unit 164. The support 162 may be disposed on the plate 120 and may include an opening 166 for the one or more platforms 130 to pass under the processing unit 164. The processing unit 164 may be supported by the support 162. In some embodiments, the processing unit 164 may include a pattern generator configured to expose a photoresist in a photolithography process. In some embodiments, the pattern generator may be configured to perform a maskless photolithography process. The processing unit 164 may include a plurality of image projection devices (e.g., Figure 2 In some embodiments, the processing unit 164 may include a plurality of light sources, such as laser diodes. Each image projection device may be disposed in a housing 165. The processing device 160 may be used to perform maskless direct patterning.

[0033] During operation, one of the one or more platforms 130 can be moved in the X direction from a loading position (eg, Figure 1The one or more platforms 130 may be moved to a processing position by moving the one or more platforms 130 along the track 150. The processing position may refer to one or more positions of the platform 130 as the platform 130 passes under the processing unit 164. During operation, the one or more platforms 130 may be lifted by a plurality of air bearings (not shown) that may be moved from a loading position to a processing position along the pair of rails 124. A plurality of vertical guide air bearings (not shown) may be coupled to each of the one or more platforms 130 and positioned near the inner wall 128 of each support 122 to stabilize the movement of the platform 130. Each of the one or more platforms 130 may also move in the Y direction by moving along the track 150 to process and / or index the substrate 140. Each of the one or more platforms 130 is capable of operating independently and may scan the substrate 140 in one direction and step in another direction. In some embodiments, while one of the one or more platforms 130 may be scanning the substrate 140, another of the one or more platforms 130 may be unloading an exposed substrate and loading the next substrate to be exposed.

[0034] The metrology system can measure the X and Y lateral position coordinates of each of the one or more platforms 130 in real time so that each of the plurality of image projection devices can accurately locate the pattern being written into the substrate covered with photoresist. The metrology system can also provide real-time measurement of the angular position of each of the one or more platforms 130 about a vertical axis or Z axis. The angular position measurement can be used to maintain a constant angular position during scanning by a servo mechanism, or can be used to align the image projection device 290 (as described below) Figure 2 Correction is applied to the position of a pattern written on substrate 140 (as shown in FIG. 1 ). These techniques may be used in any combination and are not limited.

[0035] Figure 2 FIG. 2 shows a perspective schematic diagram of an image projection system 270 of the system 100 according to some embodiments. The image projection system may include a spatial light modulator, a focus sensor and / or a camera, and a projection lens. Figure 2As shown, the image projection system 270 may include a light source 272, an aperture 274, a lens 276, a frustrated prism assembly 288, one or more digital micromirror devices (DMDs) 280 (one is shown), a light dumper 282, a focus sensor and camera 284, and / or a projection lens 286. The frustrated prism assembly 288, the DMD 280, the focus sensor and camera 284, and the projection lens 286 may be part of an image projection device 290. In some embodiments, the light source 272 may include a light emitting diode (LED) or a laser, and the light source 272 may be capable of generating light having a predetermined or adjustable wavelength. For example, the predetermined wavelength may be in the blue or near ultraviolet (UV) range, such as less than about 450 nanometers. The frustrated prism assembly 288 may include a plurality of reflective surfaces. In one embodiment, the projection lens 286 may include a 6x or 10x objective lens. Other embodiments of image projection systems that may include spatial light modulators in addition to one or more DMDs may include fewer or more components, depending on the needs of the particular spatial light modulator in the system.

[0036] The present disclosure may use a DMD as an example of a spatial light modulator. However, other spatial light modulators are also contemplated in the present disclosure. Other spatial light modulators may include, but are not limited to, liquid crystal arrays (such as liquid crystal displays (LCDs) and ferroelectric liquid crystal displays (FLCoS)) and arrays of microscopic light emitting devices (micro-LEDs). Each spatial light modulator may include an array of spatial light modulator pixels that can be switched between "on" and "off" such that a pattern of spatial light modulator pixels can modulate a light beam to provide a selected attenuation level. In operation, the spatial light modulator pixels may be controllable such that each pixel is bright, dark, and / or attenuated.

[0037] exist Figure 2 During operation of the image projection system 270 shown, a light beam 273 having a predetermined or adjustable wavelength (such as a wavelength in the blue range) can be generated by the light source 272. The light beam 273 can be reflected by the frustrated prism assembly 288 to the DMD 280. Figure 3As shown, the DMD may include a plurality of micromirrors, and the number of micromirrors may correspond to the number of pixels to be projected. The plurality of micromirrors may be individually controllable, and each of the plurality of micromirrors may be in an open position or a closed position based on mask data provided to the DMD 280 by a controller (not shown). When the light beam 273 reaches the micromirrors of the DMD 280, the micromirrors in the open position may reflect the light beam 273 (i.e., form a plurality of write light beams) to the projection lens 286. The projection lens 286 may then project the write light beam onto the surface of the substrate 140. The micromirrors in the closed position may reflect the light beam 273 to the light dumper 282 or another location instead of the surface of the substrate 140.

[0038] Figure 3 A DMD 380 according to some embodiments is shown. The DMD 380 can be used in the image projection device 290 and system 100 described above. The DMD 380 can also function in any other system or device that utilizes a DMD. The DMD 380 can include a plurality of spatial light modulator pixels (which are illustrated as micromirrors 381) arranged in a micromirror array 383. The DMD 380 can be used as a spatial light modulator, and the micromirrors 381 can be tilted at various angles and used to adjust the reflection angle of the illumination beam on the DMD 380 so that the reflected on beam is aligned with the center of the image projection device 290, and the image generated in the illumination system is centered in the projection system. In one example, the stable position of each micromirror 381 can be about plus or minus 12 degrees relative to the surface of the micromirror 381, with an error of about ±1.0 degrees. For example, the first tilt position 389 can correspond to positive 12±1.0 degrees, and the second tilt position 391 can correspond to negative 12.0±1.0 degrees.

[0039] The edges 385 of the micromirrors 381 can be arranged along orthogonal axes, such as the X-axis and the Y-axis. These axes can be congruent with similar axes referenced by the substrate 140 or the platform coordinate system after taking into account the 90-degree fold introduced by the frustrated prism assembly 288. However, the hinges 387 on the micromirrors 381 can be located at the opposite corners of the micromirrors 381, so that they pivot on axes that are 45 degrees to the X-axis and the Y-axis. As described above, these micromirrors 381 can be switched between an open position and a closed position by changing the tilt angle of the micromirrors.

[0040] In some embodiments, the hinges 387 may be oriented obliquely to tilt each micromirror 381 on an axis that is 45 degrees to the X-axis and Y-axis of each micromirror 381. In other embodiments, the hinges 387 may be oriented parallel to the edge 385 of each micromirror 381 to tilt each micromirror 381 on an axis that is parallel to the edge 385 of each micromirror 381. In one example, all hinges 387 may be oriented obliquely. In another example, all hinges 387 may be oriented parallel to the edge 385 of each micromirror 381. In another example, a first portion of the hinges 387 may be oriented obliquely and a second portion of the hinges 387 may be oriented parallel to the edge 385 of each micromirror 381.

[0041] In a conventional blazed DMD, the phase shift between adjacent micromirrors can be 0 degrees. A conventional 0 degree phase shift may result in very little cancellation. However, the phase shift between adjacent micromirrors 381 (e.g., first micromirror 381a and second micromirror 381b) of DMD 380 can be equal to or about 180 degrees. This configuration is called an anti-blazed DMD. When the phase shift between adjacent spatial light modulator pixels (e.g., first micromirror 381a and second micromirror 381b) is 180 degrees, there is exact or almost exact cancellation between adjacent micromirrors 381, and there is symmetrical brightening between adjacent pixels. In one example, each pair of adjacent micromirrors 381 has a 180 degree phase shift.

[0042] Figure 4A A pair of adjacent micromirrors directing a light beam toward a substrate is shown according to some embodiments. In this example, the first micromirror 402 and the second micromirror 404 can be configured in an "on" position to direct light toward the substrate 451 during the digital lithography process. The angle 424 of the first micromirror 402 can be in an ideal position, such as +12.0°. The angle 426 of the second micromirror 404 can be the same as the angle 424 of the first micromirror 402. When the two angles 424, 426 of the adjacent micromirrors 402, 404 are equal to the ideal value, the light beam reflected from the micromirrors 402, 404 can be directly reflected onto the substrate 451 at an angle of 90° to the substrate 451. For example, the first light beam 406 projected from the light source can be reflected vertically from the first micromirror 402 onto the substrate 451. Similarly, the second light beam 408 can also be reflected vertically from the second micromirror 404 onto the substrate 451. When the light beam hits the substrate 451 vertically, this produces vertical features and accurate layouts on the substrate 451.

[0043] In addition to ensuring that the beams are directed perpendicularly onto the substrate 451, another key consideration is the optical path difference (OPD) 420 between any two adjacent micromirrors. As shown in FIG. 4, the OPD 420 between the first beam 406 and the second beam 408 represents the difference in the total distance traveled by these beams. Specifically, it can be assumed that the distance between each of the micromirrors 402, 404 and the substrate 451 is the same. However, the distance to the light source that produces the beams 406, 408 is different because the second micromirror is farther from the light source than the first micromirror. This difference is represented by the OPD 420, which results in a phase shift between the first beam 406 and the second beam 408 on the substrate 451.

[0044] Figure 5 504. The OPD 506 between two adjacent micromirrors can cause a phase shift on the substrate according to some embodiments. The wave representation 502 of the light beam is shown as a sinusoidal waveform having a wavelength 504. The OPD 506 represents Figure 4A Assuming that the first beam 406 and the second beam 408 are in phase when the first beam 406 reflects from the first micromirror 402, the phase shift 508 can be determined by identifying the remainder when the OPD 506 is divided by the wavelength 504. Each wavelength 504 represents a full 360° phase shift (which can be neglected), so the remainder represents the phase shift between the first beam 406 and the second beam 408 on the surface of the substrate 451. As described in more detail below, phase shifts that can be accurately predicted or selected can provide many benefits in the lithography process.

[0045] Figure 4B Adjacent micromirrors are shown according to some embodiments, where the tilt angle is different from the ideal tilt angle. Figure 4A Shown is a micromirror that exhibits tilt angles 424, 426, operated in the "on" position to tilt with an accurate 12.0 ° angle, but not all DMD arrays manufactured are so accurate. Typically, the accuracy of the tilt angle may vary by as much as 1.0 ° in the DMD arrays manufactured. In order to identify the DMD arrays manufactured with sufficiently high accuracy (e.g., 12.0 ° ± 0.06 °), it may be necessary to analyze the batches of the DMD arrays manufactured to identify which DMD arrays manufactured actually fall within more stringent manufacturing tolerances. This greatly reduces the yield of the DMD arrays manufactured that can be used for the photolithography process that requires very accurate mirror tilts.

[0046] Figure 4BThe result of an undesirable tilt angle 440, 442 of the micromirrors 402, 404 is shown. Assuming that the position of the light source remains unchanged, the light beams 406, 408 may be reflected from the micromirrors 402, 404 so that the light beams 406, 408 are no longer perpendicular to the substrate 451. This may result in angled sidewalls because the light beams 406, 408 penetrate the photoresist layer on the substrate 451 at an angle. In addition, since the layers on the substrate 451 have a non-negligible thickness, the horizontal position at which the light beams 406, 408 hit the substrate 451 may vary with the depth of the top layer. Therefore, errors in the tilt angles 440, 442 of the micromirrors 402, 404 may cause the reflected light beams 406, 408 to no longer be perpendicular to the substrate 451, resulting in errors in the pattern printed on the substrate 451.

[0047] It should be noted that the spacing 422 between two adjacent micromirrors 402, 404 can be kept relatively constant within or between batches of DMD arrays manufactured. The spacing 422 can be strictly controlled during manufacturing to minimize the distance variation between each micromirror in the array.

[0048] Figure 4C 4 shows how, according to some embodiments, changes in the tilt angles 440, 442 can be accounted for by changing the angles of the light beams 406, 408. When changes in the tilt angles 440, 442 of the micromirrors 402, 404 cause the reflected light beams 406, 408 to no longer be perpendicular to the substrate 451, the angles at which the light beams 406, 408 are projected toward the micromirrors 402, 404 can be adjusted to compensate. For example, the position of the light source can be changed relative to the position of the micromirrors 402, 404. Changing the position of the light source can in turn change the angle of incidence of the light beams 406, 408 when they are reflected from the micromirrors 402, 404. Figure 4C As shown, this position can be adjusted until the beams 406 , 408 are reflected so that they are perpendicular to the substrate 451 again.

[0049] Although changing the position or angle of the light source projecting the beams 406, 408 can again make the beams 406, 408 perpendicular to the substrate 451, this may also cause the OPD to change between the beams 406, 408. For example, Figure 4C OPD 444 in relative to Figure 4A and Figure 4B The OPD 420 in has been shortened. Figure 5 As shown, changing the OPD 444 may directly affect the phase shift 508 between the light beams 406 , 408 on the substrate 451 .

[0050] During the photolithography process, different phase shifts may be required for different purposes. For example, a phase shift of 180° between adjacent micromirrors can produce a null at the boundary line between two micromirrors. This enables the photolithography pattern to produce a very dense line-space pattern, where the spacing of the line plus the space is equal to the spacing between two adjacent micromirrors to improve resolution. In another example, a phase shift of 0° between adjacent micromirrors can strengthen the pattern at the boundary. Other pattern designs can benefit from using selectable phase shifts (such as 90°, 270°, and / or any other degree of phase shift). Therefore, it may not only be necessary to maintain the selected phase shift to compensate for errors in the light source position or tilt angle, but it may also be necessary to select any phase shift based on the needs of a specific design.

[0051] To overcome this technical problem, embodiments described herein may use a variety of techniques to adjust the wavelength of the light beams 406, 408 to select or adjust the desired phase shift. Three variables may affect the phase shift, namely the spacing 422 between the micromirrors 402, 404; the length of the OPD 444; and the wavelength of the light beams 406, 408. Because the spacing 422 can be assumed to be relatively constant, and the OPD 444 can be varied to maintain a vertical beam, some embodiments may adjust the wavelength of the light beams 406, 408 to achieve or fine-tune a preselected phase shift. Figure 5 As shown, adjusting the wavelength 504 for a given OPD 506 will adjust the phase shift 508 in a manner that can be predicted and calculated.

[0052] Figure 6 A system 600 for adjusting phase shifts between pixels in a digital lithography system is shown according to some embodiments. The system 600 may include a micromirror array including Figure 6 The pair of micromirrors shown are referred to, for purposes of distinction only, as first micromirror 402 and second micromirror 404. As described above, these micromirrors 402, 404 can be oriented in an "on" position (e.g., about 12°) to direct light from light source 602 toward substrate 451, thereby printing a pattern on a layer on substrate 451 (such as a photoresist layer).

[0053] The system may include a light source 602. The light source 602 may include one or more laser diodes or other light sources configured to generate light at a preselected frequency. In order to set or adjust the phase shift based on the ODP 444 as described above, the light source 602 may be configured to adjust the wavelength of the light during operation. This adjustment may be achieved by selecting laser diodes of different colors in the light source to operate at different times. Some embodiments may adjust the wavelength by adjusting the temperature of the light source 602 to increase / decrease the wavelength. Some embodiments may include multiple light sources that may replace the position of the light source 602 to generate wavelengths of different frequencies.

[0054] Some embodiments may include a controller 604. For example, the following description Fig.13 A computer system is included that can act as a controller for operating a light source 602 as part of a lithography system. For example, the controller 604 can include one or more microprocessors or microcontrollers, and one or more non-transitory computer-readable media storing instructions that cause the microprocessors / microcontrollers to perform operations to control the frequency, operation, timing, etc. of the light source 602.

[0055] Please note, Figure 6 Only a single light source 602 is shown in FIG. This illustration is provided by way of example only and is not meant to be limiting. Light source 602 may include multiple laser diodes or other light sources. Other light sources may also be present to generate light for other micromirrors in the array. In addition, light source 602 may be responsible for generating light that is reflected as first light beam 406 and / or second light beam 408. For example, first light beam 406 and second light beam 408 may originate from the same light source 602 or from different light sources without limitation.

[0056] Figure 7 A flowchart 700 of a method for adjusting or selecting a phase shift between pixels in a digital lithography system is shown according to some embodiments. The method may include: projecting a first light beam onto a first spatial light modulator pixel (702). As described above, the first spatial light modulator pixel may include a digital micromirror. The first spatial light modulator pixel may direct the first light beam onto a substrate during a digital lithography process. The method may also include: projecting a second light beam onto a second spatial light modulator pixel (704). The second spatial light modulator pixel may also include a digital micromirror or other similar device and may similarly direct the second light beam onto a substrate during a digital lithography process. The first spatial light modulator pixel and the second spatial light modulator pixel may be positioned adjacent to each other in a pixel array. The first light beam and the second light beam may originate from the same or different light sources, such as a phase-locked laser diode or laser diode array.

[0057] This approach can be used to set or adjust the phase shift between a first light beam and a second light beam on a substrate. For example, when referring to a "preselected phase shift," this refers to a phase shift that is specifically selected between these particular micromirrors for a particular lithography process. This can be contrasted with simply using the micromirrors to generate a wavelength of light that causes OPD based on tilt error, and performing the process with the resulting phase shift. Instead, a preselected phase shift can be determined for the process, and the wavelength of light from the light source can be adjusted or selected to produce the preselected phase shift.

[0058] Therefore, the method may further include: controlling the wavelength of the first light beam and the wavelength of the second light beam based on the optical path difference between the first light beam and the second light beam (706). The wavelength may be selected or adjusted to produce a preselected phase shift between the first light beam and the second light beam on the substrate. The wavelength may be based on the above Figure 5 The OPD described above can be selected. As described above, the light source can be configured so that the wavelength of the light generated by the light source can be adjusted. The method of making such an adjustment can be: starting a different light source, adjusting the operation of the light source, adjusting the temperature of the light source, mechanically adjusting the cavity length of the laser source, electroacoustically changing the cavity of the light source, starting an alternative light source or replacing an alternative light source into the lithography system, and / or any other method of adjusting or selecting the wavelength of light to produce the desired phase shift. For example, a first subset of the plurality of laser diodes can be configured to produce a wavelength that results in a 180° phase shift. A second subset of the plurality of laser diodes can be configured to produce a wavelength that results in a 0° phase shift, while another subset of the laser diodes can be configured to produce another wavelength, such as 270°, and so on. These subsets can be started based on preselected wavelengths.

[0059] It should be understood that Figure 7 The specific steps shown provide specific methods for adjusting or selecting phase shifts between pixels in a digital lithography system according to various embodiments. Other sequences of steps may also be performed according to alternative embodiments. For example, alternative embodiments may perform the steps outlined above in a different order. In addition, Figure 7 Each step shown may include multiple sub-steps, which may be performed in various sequences according to the circumstances of each step. In addition, additional steps may also be added or removed depending on a specific application. Many variations, modifications, and alternatives also fall within the scope of this disclosure.

[0060] A specific method of adjusting the effective wavelength of a light source used in a photolithography process will now be described. This method involves using multiple light sources with different frequencies and adjusting the intensity of these light sources to produce a phase shift effect on the substrate.

[0061] Figure 8 A light source 800 is shown that can be used in a lithography system according to some embodiments. This light source 800 is provided by way of example only and is not meant to be limiting. Other light sources or other similar equipment having laser diodes with different groupings and configurations can be used in its place. This light source 800 can include a laser module 802. The laser module 802 can include multiple laser diodes. In some embodiments, the laser diodes can be divided into several groups, and these groups can include multiple matched laser diodes that are driven by corresponding drive circuit systems. Each group can have multiple laser diodes with similar wavelengths. Please note that for clarity, Figure 8 Four groups of four laser diodes are shown by way of simplified example only. As indicated by the abbreviations, any number of laser diodes and groups may be used without limitation.

[0062] For the embodiments described below, some groups may include laser diodes configured to emit light having a wavelength shorter than a preselected wavelength, while some groups may include laser diodes configured to emit light having a wavelength longer than a preselected wavelength. For example, a first group 808 may be driven by a first drive circuit system 806 and configured to produce light of a higher wavelength, while a second group 838 may be driven by a second drive circuit system 833 and configured to produce light of a lower wavelength.

[0063] The system may include a controller 804 configured to control the intensity of each group of laser diodes. For example, the controller 804 may use a microprocessor, a microcontroller, and / or a controller as described below. Fig.13 804. The controller 804 may make the intensity of the first group 808 higher than the intensity of the second group 838, and vice versa. The controller 804 may calculate the appropriate intensity for each group in the laser module 802, as described in detail below.

[0064] Each laser diode in the laser module 802 can be coupled to a corresponding optical fiber 814. These optical fibers can be bundled together and aligned with a homogenizing rod 816 or other form of light pipe that perturbs the light into a uniform illumination beam, which can be projected onto the micromirrors in the array. Thus, each "beam" described above can include multiple components from different groups of light laser diodes that produce light of different wavelengths. For example, a first light component can be produced at one wavelength by the laser diodes of the first group 808, while a second light component can be produced at another wavelength by the laser diodes of the second group 838. The output of the homogenizing rod 816 can be light 818, which is directed into one or more beams as described above. For example, light 818 can be produced at Figures 4A-4C and the sources of the first and second light beams as described elsewhere in this disclosure.

[0065] Fig. 9A system 900 for using a beam of light having multiple wavelengths bracketing a preselected wavelength is shown in accordance with some embodiments. System 900 is similar to the system described above, but a light source 911 can be configured to produce a first light beam 406 having at least two different components. For example, a first component can be produced using a laser diode that outputs light at a wavelength greater than a preselected wavelength, where the preselected wavelength corresponds to a desired phase shift between the first light beam 406 and the second light beam 408 on the substrate 451. Similarly, a second component can be produced using a laser diode that outputs light at a wavelength less than the preselected wavelength. Alternatively, the first component and the second component can be characterized based on their corresponding phase shifts relative to a preselected phase shift. The first component can produce a phase shift greater than the preselected phase shift, and the second component can produce a phase shift less than the preselected phase shift. The two components 902, 904 can be mixed together to form the first light beam 406. As described above, the light source 911 can also produce a second light beam 408 that is projected onto the second micromirror 404, although this is not necessary in the embodiment of the present invention. Fig. 9 Alternatively, a second light source (not shown) may generate the second light beam 408.

[0066] The light source 911 may include a controller as described above that controls the intensity of the first component 902 and the intensity of the second component 904. It has been found that by surrounding a preselected wavelength or phase shift on the substrate with wavelengths or phase shifts higher and lower than the preselected wavelength or phase shift, the effect of the preselected phase shift can be approximated by the combined light intensity of the two components on the substrate. In addition, by adjusting the relative intensity between the first component 902 and the second component 904, the effective phase shift can be tuned or adjusted between the phase shift of the first component 902 and the phase shift of the second component 904 using a weighted combination of phase shifts.

[0067] Fig.10 A graph 1000 is shown of the effect of using a beam having multiple light components surrounding a preselected phase shift according to some embodiments. In this example, the preselected phase shift is selected to be 0°. This corresponds to a preselected wavelength that can be calculated based on the OPD of a particular micromirror array. Therefore, the preselected phase shift and the preselected wavelength can be used interchangeably because they are easily derived from each other. Curve 1008 shows the light intensity on the surface of the substrate. The vertical axis of the graph 1000 represents the light intensity on the substrate using a normalized scale of arbitrary units. The horizontal axis of the graph 1000 represents the position on the substrate in microns (μm). The position of 0 microns corresponds to the center position between the first micromirror and the second micromirror that can be adjacent in the array. The spacing between the two micromirrors can be about 1.26 microns, which roughly corresponds to the peak on the curve in the graph 1000. The results of the graph 1000 are based on a defocus level of about -3 microns.

[0068] Because light sources may not be readily available for the preselected wavelength corresponding to a 0° phase shift, first and second components having phase shifts greater than and less than the preselected phase shift may be used simultaneously. In this example, the first component corresponding to curve 1004 represents a wavelength that produces a phase shift of approximately 10° (e.g., 350°) less than a 0° phase shift, while the second component corresponding to curve 1002 represents a wavelength that produces a phase shift of approximately 20° greater than a 0° phase shift. Note that these curves are individually different from curve 1008 corresponding to a preselected wavelength that produces a preselected 0° phase shift.

[0069] However, when the first component and the second component are combined to form a beam reflected from the micromirror, the overall light intensity on the substrate can be made to approximate the effect of a preselected phase shift of a preselected wavelength. For example, the two components can be combined in a linear combination, where the weight assigned to each component corresponds to the difference in its corresponding phase shift relative to the preselected phase shift. In this embodiment, the weight assigned to each component makes the linear combination of the two components approximately equal to zero. For example, a component with a -10° phase shift relative to a preselected 0° phase shift can be multiplied by 2 / 3, while a component with a +20° phase shift relative to a preselected 0° phase shift can be multiplied by 1 / 3, so that the linear combination of these components is approximately equal to zero. These weights can then be used to control the brightness or intensity of each component. For example, the intensity of a component with a -10° phase shift can be approximately twice the intensity of a component with a +20° phase shift. As described above, the intensity of each component can be dynamically controlled by a controller during operation.

[0070] The combination of the two components when the intensity of each component is controlled is illustrated as curve 1006 in graph 1000. Note that curve 1006 for the combined component is very close to curve 1008 corresponding to an ideal phase shift for a preselected wavelength. This shows how the effects of the first and second components can be used to approximate the effect of a preselected phase shift or wavelength on a substrate by controlling the intensities of the components.

[0071] Fig.11 Graphs are shown illustrating how multiple components can be used to approximate and tune any preselected wavelength, in accordance with some embodiments. While 0° and 180° have been described above as example phase shifts, these embodiments can be easily used to produce any phase shift at any defocus level between any two micromirrors in an array. For example, graph 1100 shows approximation of a 0° phase shift at a +3 micron defocus length, graph 1102 shows approximation of a 180° phase shift at a 0 micron defocus length, graph 1106 shows approximation of a 90° phase shift at a +3 micron defocus length, and graph 1108 shows approximation of a 280° phase shift at a 0 micron defocus length. These graphs illustrate how these techniques can be used to approximate any phase shift.

[0072] In these examples, the phase shifts or wavelengths surrounding the preselected phase shift or preselected wavelength have been selected so that the higher phase shift is about 20° greater than the preselected phase shift and the lower phase shift is about 10° less than the preselected phase shift. Although the effect of this particular surrounding of the preselected phase shift to closely approximate the preselected phase shift has been shown, not all embodiments need to use these specific values. For example, other embodiments may use a first component with a phase shift value that is relatively greater than about 5° to about 10°, relatively greater than about 10° to about 15°, relatively greater than about 15° to about 20°, relatively greater than about 20° to about 25°, relatively greater than about 25° to about 30°, and so on. Similarly, other embodiments may use a second component with a phase shift value that is relatively less than about 5° to about 10°, relatively less than about 10° to about 15°, relatively less than about 15° to about 20°, relatively less than about 20° to about 25°, relatively less than about 25° to about 30°, and so on. Each of these different ranges can be used in different combinations without limitation and with different advantages depending on the particular lithographic pattern, laser diode type, photoresist material, and / or other characteristics of the lithographic system.

[0073] The above system can use the same wavelength mixing in the laser diode for the DMD as a whole. This enables the system to correct the average error of the mirror tilt angle of each DMD. However, some embodiments can additionally correct the individual micromirror tilt errors of the DMD array itself. For example, the individual wavelength mixing and incident angle on the DMD can be adjusted based on the tilt error of each individual micromirror. These embodiments can change the light source, intensity and light angle to compensate for the regional changes in the micromirror tilt angle.

[0074] The above example shows only two components of the light beam by way of example. However, other embodiments may use more than two components for the light beam. For example, the preselected phase shift may be surrounded by three, four, five, etc. components, whose phase shifts are greater and / or less than the predetermined phase shift. The relative brightness of each of these components may be determined using a weighted combination of the light components described above. Specifically, the weights corresponding to the intensities may be calculated such that the weighted combination of the phase shift deviations relative to the preselected phase shift is approximately zero.

[0075] Fig.12A flowchart 1200 of a method for selecting or adjusting a phase shift between pixels in a digital lithography system is shown according to some embodiments. The method may include: projecting a first light beam onto a first spatial light modulator pixel (1202). As described above, the first spatial light modulator pixel may include a digital micromirror. The first spatial light modulator pixel may direct the first light beam onto a substrate during a digital lithography process. The method may also include: projecting a second light beam onto a second spatial light modulator pixel (1204). The second spatial light modulator pixel may also include a digital micromirror or other similar device and may similarly direct the second light beam onto a substrate during a digital lithography process. The first spatial light modulator pixel and the second spatial light modulator pixel may be positioned adjacent to each other in a pixel array. The first light beam and the second light beam may originate from the same or different light sources, such as a laser diode or a laser diode array.

[0076] The first light beam may include a plurality of components, including a first component having a first wavelength, the first wavelength producing a first phase shift greater than a preselected phase shift. Similarly, the plurality of components may also include a second component having a second wavelength, the second wavelength producing a second phase shift less than the preselected phase shift. The preselected phase shift may correspond to a desired phase shift between the light beams reflected by the two micromirrors onto the substrate. As described above, in addition to the two specific components described above, the plurality of components in the first light beam may also include other components. The same light source that produces the first light beam may also produce the second light beam, and thus the second light beam may also include these components.

[0077] The method may further include controlling the intensities of the plurality of components to produce an effect on the substrate that approximates a preselected phase shift (1206). The intensity of each component may be controlled based on a linear combination of the deviations of the corresponding phase shift from the preselected phase shift. The weights applied to each of the phase shift deviations in the weighted combination may be calculated so that the linear combination is approximately zero. The weighted combination may include any number of components in the light beam. Approximating the preselected phase shift may produce a light intensity pattern on the substrate that approximates the light intensity pattern that would occur if a single wavelength corresponding to the preselected phase shift were used.

[0078] It should be understood that Fig.12 The specific steps shown provide specific methods for selecting or adjusting the phase shift between pixels in a digital lithography system according to various embodiments. Other sequences of steps may also be performed according to alternative embodiments. For example, alternative embodiments may perform the steps outlined above in a different order. In addition, Fig.12Each step shown may include multiple sub-steps, which may be performed in various sequences according to the circumstances of each step. In addition, additional steps may also be added or removed depending on a specific application. Many variations, modifications, and alternatives also fall within the scope of this disclosure.

[0079] Each method described herein can be implemented by a computer system. Each step of these methods can be automatically performed by a computer system, and / or can be provided with input / output involving a user. For example, a user can provide input for each step in the method, and each of these inputs can be a response to a specific output requesting such input, wherein the output is generated by a computer system. Each input can be received in response to a corresponding request output. In addition, the input can be received from a user, received as a data stream from another computer system, retrieved from a memory location, retrieved via a network, requested from a network service, and / or similar means. Similarly, the output can be provided to a user, provided to another computer system as a data stream, stored in a memory location, sent via a network, provided to a network service, and / or similar means. In short, each step of the method described herein can be performed by a computer system, and can involve any number of inputs, outputs, and / or requests entering and exiting a computer system, which may or may not involve a user. Those steps that do not involve a user can be said to be automatically performed by a computer system without manual intervention. Therefore, it will be understood from this disclosure that each step of each method described herein can be changed to include input and output to and from a user, or can be completed automatically by a computer system without human intervention, where any decisions are made by the processor. In addition, some embodiments of each method described herein can be implemented as a set of instructions that are stored on a tangible, non-transitory storage medium to form a tangible software product.

[0080] Fig.13 An exemplary computer system 1300 is shown in which various embodiments can be implemented. System 1300 can be used to implement any of the computer systems or controllers described above. For example, system 1300 can be used to implement a controller that controls the intensity of each component of light projected onto the micromirror and reflected onto the substrate during the above-mentioned photolithography process. As shown, computer system 1300 includes a processing unit 1304, which communicates with some peripheral subsystems via a bus subsystem 1302. These peripheral subsystems can include a processing acceleration unit 1306, an I / O subsystem 1308, a storage subsystem 1318, and a communication subsystem 1324. Storage subsystem 1318 includes a tangible computer-readable storage medium 1322 and a system memory 1310.

[0081] The bus subsystem 1302 provides a mechanism for the various components and subsystems of the computer system 1300 to communicate with each other in an expected manner. Although the bus subsystem 1302 is schematically illustrated as a single bus, alternative embodiments of the bus subsystem may also utilize multiple buses. The bus subsystem 1302 may be any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. For example, such an architecture may include an industry standard architecture (ISA) bus, a microchannel architecture (MCA) bus, an enhanced ISA (EISA) bus, a video electronics standards association (VESA) local bus, and a peripheral component interconnect (PCI) bus, which may be implemented as a mezzanine bus manufactured in accordance with the IEEE P1386.1 standard.

[0082] The processing unit 1304, which may be implemented as one or more integrated circuits (e.g., a conventional microprocessor or microcontroller), controls the operation of the computer system 1300. One or more processors may be included in the processing unit 1304. These processors may include single-core or multi-core processors. In some embodiments, the processing unit 1304 may be implemented as one or more independent processing units 1332 and / or 1334, each of which includes a single-core or multi-core processor. In other embodiments, the processing unit 1304 may also be implemented as a quad-core processing unit, which is formed by integrating two dual-core processors into a single chip.

[0083] In various embodiments, the processing unit 1304 can execute various programs in response to program code, and can maintain multiple programs or processes executing in parallel. At any given time, some or all of the program code to be executed may reside in the processor 1304 and / or the storage subsystem 1318. Through appropriate programming, the processor 1304 can provide the various functionalities described above. The computer system 1300 can additionally include a processing acceleration unit 1306, which can include a digital signal processor (DSP), a special purpose processor, and / or the like.

[0084] I / O subsystem 1308 may include user interface input devices and user interface output devices. User interface input devices may include keyboards, pointing devices such as a mouse or trackball, a touch pad or touch screen incorporated into a display, scroll wheels, click wheels, dials, buttons, switches, keypads, audio input devices with voice command recognition systems, microphones, and other types of input devices. User interface input devices may include, for example, motion sensing and / or gesture recognition devices such as Microsoft Motion sensors that enable users to control input devices (such as Microsoft 360 game controller) and interact with it. User interface input devices can also include eye gesture recognition devices, such as Google Blink detector, which detects eye activity from the user (e.g. 'blinking' when taking a picture and / or making a menu selection) and translates eye gestures into input devices (e.g. Google ) input. In addition, the user interface input device may also include a voice recognition sensing device, which enables the user to communicate with the voice recognition system (e.g. Navigator) to interact.

[0085] User interface input devices may also include, but are not limited to, three-dimensional (3D) mice, rockers or pointing sticks, game controllers and graphics tablets, and audio / visual devices such as speakers, digital cameras, digital camcorders, portable media players, webcams, image scanners, fingerprint scanners, barcode readers, three-dimensional scanners, three-dimensional printers, laser rangefinders, and eye tracking devices. In addition, user interface input devices may also include, for example, medical imaging input devices such as computed tomography, magnetic resonance imaging, positron emission tomography, and medical ultrasound scanning devices. User interface input devices may also include, for example, audio input devices such as MIDI keyboards, digital musical instruments, and similar devices.

[0086] User interface output devices may include a display subsystem, indicator lights, or non-visual displays such as audio output devices. The display subsystem may be a cathode ray tube (CRT), a flat panel device (such as a liquid crystal display (LCD) or plasma display), a projection device, a touch screen, and the like. In general, the use of the term "output device" is intended to include all possible types of devices and mechanisms for outputting information from the computer system 1300 to a user or other computer. For example, user interface output devices may include, but are not limited to, various display devices that visually convey text, graphics, and audio / video information, such as monitors, printers, speakers, headphones, car navigation systems, plotters, voice output devices, and modems.

[0087] Computer system 1300 may include storage subsystem 1318, which includes software elements illustrated as being presently located within system memory 1310. System memory 1310 may store program instructions that may be loaded and executed on processing unit 1304, as well as data generated during the execution of such programs.

[0088] Depending on the configuration and type of computer system 1300, system memory 1310 may be volatile (such as random access memory (RAM)) and / or non-volatile (such as read-only memory (ROM), flash memory, etc.). RAM typically contains data and / or program modules that are immediately accessible to and / or currently being operated and executed by processing unit 1304. In some embodiments, system memory 1310 may include a variety of different types of memory, such as static random access memory (SRAM) or dynamic random access memory (DRAM). In some embodiments, a basic input / output system (BIOS) containing basic routines that help transfer information between elements of computer system 1300 (such as during startup) may typically be stored in ROM. By way of example and not limitation, system memory 1310 also illustrates application programs 1312, which may include client applications, web browsers, mid-tier applications, relational database management systems (RDBMS), etc., program data 1314, and operating system 1316. For example, operating system 1316 may include various versions of Microsoft Apple and / or Linux operating system, various commercially available or UNIX-like operating systems (including but not limited to various GNU / Linux operating systems, Google OS and similar operating systems) and / or mobile operating systems such as iOS, Phone, OS, 10OS and OS operating system.

[0089] Storage subsystem 1318 may also provide a tangible computer-readable storage medium for storing basic programming and data structures that provide the functionality of some embodiments. Software (programs, code modules, instructions) that provide the above functionality when executed by a processor may be stored in storage subsystem 1318. These software modules or instructions may be executed by processing unit 1304. Storage subsystem 1318 may also provide a repository for storing data used in accordance with some embodiments.

[0090] Storage subsystem 1300 may also include a computer-readable storage media reader 1320, which may further interface with computer-readable storage media 1322. Together with system memory 1310, and optionally in conjunction with the system memory, computer-readable storage media 1322 may collectively represent remote, local, fixed and / or removable storage devices, plus storage media for temporarily and / or more permanently containing, storing, transmitting, and retrieving computer-readable information.

[0091] The computer-readable storage medium 1322 containing code or code portions may also include any suitable media, including storage media and communication media, such as, but not limited to, volatile and non-volatile, removable and non-removable media implemented in any method or technology to store and / or transmit information. This may include tangible computer-readable storage media, such as RAM, ROM, electronically erasable programmable ROM (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or other tangible computer-readable media. This may also include intangible computer-readable media, such as data signals, data transmissions, or any other medium that can be used to transmit the desired information and can be accessed by the computing system 1300.

[0092] For example, computer readable storage media 1322 may include hard disk drives that read from or write to non-removable, non-volatile magnetic media, magnetic disk drives that read from or write to removable, non-volatile magnetic disks, and removable, non-volatile optical disks (such as CD ROMs, DVDs, and Computer readable storage media 1322 may include, but is not limited to, The computer readable storage medium 1322 may also include a solid-state drive (SSD) based on nonvolatile memory, such as a flash memory-based SSD, an enterprise flash drive, a solid-state ROM, and the like, a volatile memory-based SSD, such as a solid-state RAM, a dynamic RAM, a static RAM, a DRAM-based SSD, a magnetoresistive RAM (MRAM) SSD, and a hybrid SSD using a combination of DRAM and a flash memory-based SSD. The disk drive and its associated computer readable media may provide nonvolatile storage of computer readable instructions, data structures, program modules, and other data for the computer system 1300.

[0093] The communication subsystem 1324 provides an interface with other computer systems and networks. The communication subsystem 1324 acts as an interface for receiving data from and transmitting data to other systems of the computer system 1300. For example, the communication subsystem 1324 can enable the computer system 1300 to be connected to one or more devices via the Internet. In some embodiments, the communication subsystem 1324 may include a radio frequency (RF) transceiver component for accessing a wireless voice and / or data network (e.g., using cellular phone technology, advanced data network technology (such as 3G, 4G or EDGE (Enhanced Data Rates for Global Evolution)), WiFi (IEEE 802.11 series standards, or other mobile communication technologies, or any combination thereof), a global positioning system (GPS) receiver component, and / or other components. In some embodiments, in addition to or in lieu of a wireless interface, the communication subsystem 1324 may provide wired network connectivity (e.g., Ethernet).

[0094] In some implementations, the communication subsystem 1324 may also receive incoming communications in the form of structured and / or unstructured data feeds 1326 , event streams 1328 , event updates 1330 , and the like on behalf of one or more users who may be using the computer system 1300 .

[0095] For example, the communication subsystem 1324 may be configured to receive data feeds 1326 in real time from users of social networks and / or other communication services, such as feed, Updates, web feeds (such as Rich Site Summary (RSS) feeds), and / or real-time updates from one or more third-party information sources.

[0096] In addition, the communication subsystem 1324 can also be configured to receive data in the form of a continuous data stream, which can include an event stream 1328 of real-time events and / or event updates 1330, which can be continuous or unbounded in nature, without a clear end. Examples of applications that generate continuous data can include, for example, sensor data applications, financial stocks, network performance measurement tools (e.g., network monitoring and traffic management applications), clickstream analysis tools, automobile traffic monitoring, and similar applications.

[0097] The communication subsystem 1324 may also be configured to output structured and / or unstructured data feeds 1326 , event streams 1328 , event updates 1330 , and the like to one or more databases that may be in computer communication with one or more streaming data source computers coupled to the computer system 1300 .

[0098] Computer system 1300 may be one of various types, including a handheld portable device (e.g., cell phone, computing tablets, PDAs), wearable devices (e.g., Google head mounted display), PC, workstation, mainframe, kiosk, server rack or any other data processing system.

[0099] Due to the ever-changing nature of computers and networks, the description of the computer system 1300 depicted in the figure is intended to serve only as a specific example. Many other configurations with more or fewer components than the system depicted in the figure are possible. For example, customized hardware may also be used, and / or specific elements may be implemented in hardware, firmware, software (including applets), or in combination. Further, connections with other computing devices, such as network input / output devices, may be employed. Based on the disclosure and teachings provided herein, other ways and / or methods of implementing various embodiments should be apparent.

[0100] As used herein, the terms “about” or “approximately” or “substantially” may be interpreted as being within the range that would be expected by a person of ordinary skill in the art based on the description.

[0101] In the above description, for the purpose of explanation, numerous specific details are set forth to provide a comprehensive understanding of various embodiments. However, it will be apparent that some embodiments may be practiced without some of these specific details. In other cases, well-known structures and devices are illustrated in the form of block diagrams.

[0102] The above description provides only exemplary embodiments and is not intended to limit the scope, applicability or configuration of the disclosure. On the contrary, the above description of various embodiments will provide disclosures that can be used to implement at least one embodiment. It should be understood that various changes can be made to the function and arrangement of elements without departing from the spirit and scope of some embodiments set forth in the appended claims.

[0103] Specific details are given in the above description to provide a comprehensive understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may have been illustrated as components in the form of block diagrams so as not to obscure the embodiments with unnecessary detail. In other cases, well-known circuits, processes, algorithms, structures, and techniques may have been illustrated without unnecessary detail so as not to obscure the embodiments.

[0104] Also, it should be noted that various embodiments may have been described as a process, which is depicted as a flowchart (flow diagram), data flow diagram, structure diagram or block diagram. Although the flowchart may have described the operations as a sequential process, many operations may also be performed in parallel or in parallel. In addition, the order of the operations may also be rearranged. A process is terminated after its operations are completed, but there may be additional steps not included in the figure. A process may correspond to a method, function, program, subroutine, subprogram, etc. When a process corresponds to a function, its termination may correspond to the return of the function to the calling function or main function.

[0105] The term "computer-readable medium" includes, but is not limited to, portable or fixed storage devices, optical storage devices, wireless channels, and various other media capable of storing, containing, or carrying instructions and / or data. Code snippets or machine-executable instructions may represent programs, functions, subroutines, programs, routines, subroutines, modules, packaged software, classifications, or any combination of instructions, data structures, or program statements. Code snippets may be coupled to another code snippet or hardware circuit by transmitting and / or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be transmitted, forwarded, or transmitted via any suitable means (including memory sharing, information transmission, token transmission, network transmission, etc.).

[0106] In addition, the embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description language, or any combination thereof. When implemented in software, firmware, middleware, or microcode, program code or code segments for performing the necessary tasks may be stored in a machine-readable medium. A processor may perform the necessary tasks.

[0107] In the above description, reference is made to the specific embodiments of features to describe them, but it should be appreciated that not all embodiments are limited thereto. The various features and aspects of some embodiments may be used alone or in combination. In addition, without departing from the broader spirit and scope of this specification, the embodiments may be used in any number of environments and applications other than those described herein. Therefore, this specification and the accompanying drawings should be considered illustrative rather than restrictive.

[0108] In addition, for the purpose of illustration, the method is described in a specific order. It should be understood that, in alternative embodiments, these methods can be performed in an order different from the described order. It should also be understood that the above method can be performed by hardware components, or it can be implemented in a sequence of machine executable instructions, which can be used to cause a machine (such as a general or special-purpose processor or logic circuit programmed to have these instructions) to perform these methods. These machine executable instructions can be stored on one or more machine-readable media, such as CD-ROM or other types of optical disks, floppy disks, ROM, RAM, EPROM, EEPROM, magnetic cards or optical cards, flash memory, or other types of machine-readable media suitable for storing electronic instructions. Alternatively, these methods can be performed by a combination of hardware and software.

Claims

1. A digital lithography system, comprising: a first spatial light modulator pixel configured to direct a first light beam onto a substrate during a digital lithography process; a second spatial light modulator pixel configured to direct a second light beam onto the substrate during the digital lithography process; A light source is configured to generate the first light beam, wherein the first light beam includes a plurality of components, the plurality of components including: a first component having a first wavelength that produces a first phase shift greater than a preselected phase shift; and a second component having a second wavelength that produces a second phase shift that is less than the preselected phase shift; and A controller is configured to control the intensities of the plurality of components to produce an effect on the substrate that approximates the preselected phase shift.

2. The system of claim 1, wherein the second spatial light modulator pixel is adjacent to the first spatial light modulator pixel in an array of spatial light modulator pixels in a digital micromirror device.

3. The system of claim 1, wherein the first spatial light modulator pixel comprises a micromirror that adjusts between an on position that reflects light onto the substrate and a off position that reflects light away from the substrate. 4 . The system of claim 1 , wherein the light source is further configured to generate the second light beam such that the first light beam and the second light beam originate from the light source.

5. The system of claim 1 , wherein the second light beam is generated from a different light source, and the controller is further configured to control the intensity of a component in the second light beam to correct a tilt error of a pixel of the second spatial light modulator, the tilt error being different from a tilt error of a pixel of the first spatial light modulator.

6. The system of claim 1, wherein the light source comprises a plurality of groups of laser diodes, wherein a first subset of the plurality of groups of laser diodes is configured to output substantially the first wavelength and a second subset of the plurality of groups of laser diodes is configured to output substantially the second wavelength.

7. The system of claim 1, wherein the light source comprises a homogenizing rod that mixes the first component with the second component to produce a uniform first light beam.

8. The system of claim 1, wherein the plurality of components further comprises a plurality of additional components in addition to the first component and the second component.

9. A method for adjusting phase shift between pixels in a digital lithography system, the method comprising: projecting a first light beam onto a first spatial light modulator pixel, wherein the first spatial light modulator pixel directs the first light beam onto a substrate during a digital lithography process, wherein the first light beam comprises a plurality of components, the plurality of components comprising: a first component having a first wavelength that produces a first phase shift greater than a preselected phase shift; and a second component having a second wavelength that produces a second phase shift that is less than the preselected phase shift; projecting a second light beam onto a second spatial light modulator pixel, wherein the second spatial light modulator pixel directs the second light beam onto the substrate during the digital lithography process; and The intensities of the plurality of components are controlled to produce an effect on the substrate that approximates the preselected phase shift.

10. The method of claim 9, wherein the first wavelength produces a first phase shift that is approximately 20° greater than the preselected phase shift.

11. The method of claim 9, wherein the second wavelength produces a second phase shift that is approximately 10° less than the preselected phase shift.

12. The method of claim 9, wherein the preselected phase shift can be selected to be any phase shift between 0° and 359°.

13. The method of claim 9, wherein the step of controlling the intensities of the plurality of components comprises: A weight in a linear combination of the deviations of the first phase shift and the second phase shift relative to the preselected phase shift is calculated for each of the plurality of components such that the linear combination is approximately zero. The method of claim 13 , wherein the weights in the linear combination correspond to the intensities of the plurality of components.

15. The method of claim 9, wherein the step of approximating the preselected phase shift produces a light intensity pattern on the substrate that approximates a light intensity pattern that would appear on the substrate if a single wavelength corresponding to the preselected phase shift was used.

16. The method of claim 9, wherein the first phase shift is calculated based on the first wavelength and an optical path difference between the first light beam and the second light beam.

17. The method of claim 9, wherein the second spatial light modulator pixel is adjacent to the first spatial light modulator pixel in a spatial light modulator pixel array in a digital micromirror device, and the second light beam also includes the first component and the second component.

18. A method of adjusting or selecting a phase shift between pixels in a digital lithography system, the method comprising: projecting a first light beam onto a first spatial light modulator pixel, wherein the first spatial light modulator pixel directs the first light beam onto a substrate during a digital lithography process; projecting a second light beam onto a second spatial light modulator pixel, wherein the second spatial light modulator pixel directs the second light beam onto the substrate during the digital lithography process and the second spatial light modulator pixel is adjacent to the first spatial light modulator pixel in an array of spatial light modulator pixels; as well as The wavelength of the first light beam and / or the wavelength of the second light beam is controlled based on an optical path difference between the first light beam and the second light beam to produce a preselected phase shift between the first light beam and the second light beam on the substrate.

19. The method of claim 18, wherein the step of controlling the wavelength of the first light beam comprises: Switch between different laser diodes that produce light with different wavelengths.

20. The method of claim 18, wherein the step of controlling the wavelength of the first light beam comprises: The wavelength of the first light beam is changed by controlling the temperature of a light source, mechanically changing a cavity of the light source, or electroacoustically changing the cavity of the light source.

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