Device and method for exposing a photosensitive layer using an optical system

Abstract

The present invention relates to different focal planes. The present invention relates to a method for exposing a photosensitive layer having an optical system, wherein in each case at least one light beam is generated by at least one light source and pixels of an exposure pattern are illuminated by at least one micromirror device, the at least one micromirror device having a plurality of micromirrors each having a mirror intensity distribution, characterized in that the mirror intensity distributions of adjacent micromirrors overlap to obtain a pattern intensity distribution of the exposure pattern, resulting in the sum of the mirror intensity distributions of the illuminated pixels of the exposure pattern. Furthermore, the present invention relates to an apparatus for exposing a photosensitive layer using an optical system having at least one light source and at least one micromirror device having a plurality of micromirrors, wherein the optical system is designed such that the mirror intensity distributions of adjacent micromirrors overlap to form a pattern intensity distribution of the exposure pattern, resulting in the sum of the mirror intensity distributions of the illuminated pixels of the exposure pattern.

Description

[0001] This application is a divisional application of the invention patent application with application date of December 20, 2016, application number 201680091750.1 (international application number PCT / EP2016 / 081880) and invention name “Device and method for exposing a photosensitive layer”. Technical Field

[0002] The present invention relates to a method for exposing a photosensitive layer according to technical solution 1 and a corresponding device according to technical solution 8. Background Art

[0003] Digital micromirror devices (DMDs) have long been known in the prior art. These are optical components consisting of multiple small mirrors that can be individually moved / aligned. Each mirror can be electrically controlled and oriented in a targeted manner. Thus, an optical system with a DMD can be used to deflect a wide range of light in a selective, spatially resolved manner. In most cases, each mirror observes only two fully deflected positions. A mirror allows the portion of light that falls on it to pass further through the optical system or reflects it so that it is not forwarded in the optical system. Each mirror of the DMD can then be interpreted as a digital optical switch.

[0004] This type of DMD has been used in prior art, primarily in projectors. DMDs are also increasingly used in industrial fields such as, for example, 3D printing, 3D metrology, and maskless lithography.

[0005] In the prior art, only shieldless exposure units are known, which have a single light source illuminating the DMD (and thus the surface to be exposed). Summary of the Invention

[0006] It is therefore an object of the present invention to overcome the disadvantages of the prior art and, in particular, to obtain an improved exposure result.

[0007] This object is achieved by the objectives of the mutually coordinated patent claims and the inventive concepts disclosed below. Advantageous developments of the invention are described in detail in the dependent claims. All combinations of at least two features described in detail in this specification, the claims, and / or the figures also fall within the scope of the present invention. With respect to value ranges, values ​​within the stated limits are also disclosed as limiting values ​​and may be claimed in any desired combination.

[0008] In particular, the present invention shows how to implement an improved faster, high-resolution exposure process and how an exposure can occur simultaneously at different focus depths.

[0009] The core concept of the present invention is to construct the micromirrors of a micromirror device of an optical system in such a way that the mirror intensity distributions of the micromirrors overlap or are constructed so that they overlap with the intensity distributions of adjacent mirrors. Thus, each mirror intensity distribution consists of an area corresponding to the pixel and an area surrounding the pixel. The mirror intensity distributions are defined at least primarily (and preferably entirely) by the optical components and the geometry of the micromirrors. The micromirrors are preferably rectangular, more preferably square. Circular or triangular micromirrors are also conceivable. A DMD image is formed by pixels comprising overlaps.

[0010] Specifically, an exposure pattern is generated that consists of a plurality of mirror intensity distributions that at least partially overlap with a pattern intensity distribution. Thus, the pattern intensity distribution is the sum of the overlapping mirror intensity distributions. The exposure pattern preferably exposes a layer section to be exposed on a substrate, wherein the pattern intensity distribution of the exposure pattern is preferably more uniform due to the overlap than an exposure pattern without overlap from the prior art.

[0011] The mirror intensity distribution is preferably selected, adjusted, or controlled so that 50% of the energy deflected by each mirror impinges on the corresponding pixel. Another 50% of the energy deflected by each mirror is divided among pixels surrounding the respective pixel. In a more preferred embodiment of the present invention, the mirror intensity distribution is selected, adjusted, or controlled so that more than 50% (more preferably more than 60%, more preferably more than 70%) of the energy deflected by each mirror impinges on the corresponding pixel. The remaining energy is divided among pixels surrounding the respective pixel.

[0012] In a different less preferred embodiment according to the invention, the mirror intensity distribution is chosen such that less than 50% of the energy deflected by the respective mirror impinges on the corresponding pixel.

[0013] Specifically, the present invention describes a maskless exposure apparatus or a maskless exposure method. The exposure unit is described in several embodiments that can be combined with one another. Specifically, these are optimization options that are independent of one another but can be combined with one another.

[0014] The most important embodiment is to design the optical system in such a way that an overlap of the individual pixels (the pixels generated by the optical system) occurs (in particular, using overlap and / or interference). In particular, this has the effect that the intensity distributions of the deflected light of adjacent micromirrors overlap.

[0015] In particular, a shieldless exposure device having at least two light sources is disclosed, wherein (in particular) the light from the light sources overlaps, combines or mixes.

[0016] According to the present invention, a maskless exposure device with integrated metrology is also contemplated. A further embodiment relates to a maskless exposure unit that allows simultaneous exposure of different focal planes or simultaneous exposure of spectrally different image portions. According to a further alternative embodiment, an exposure unit with an anisotropic or anamorphic optical system for achieving higher resolution is disclosed.

[0017] A further, specifically, independently disclosed embodiment relates to a "descan" method for increasing throughput and resolution. Here, the exposure process is overlapped (specifically, continuously or sequentially) by a second deflection in one or two directions. This allows the exposure field to be determined quasi-statically with a positioning accuracy finer than the pixel size, thereby reducing both motion blur and edge position.

[0018] Furthermore, embodiments are disclosed in which an optical system generates an orthogonal distorted representation of the original image (specifically, parallel to the surface of the layer to be exposed) between the DMD and the photosensitive layer to be exposed (the material to be exposed). Specifically, optical distortion of the image can be used to increase positioning accuracy or overlay. It will be appreciated that in certain cases, positioning accuracy of an existing structure, i.e., the resolution of the structure to be written, is increased by distorted representation of the original image according to the present invention.

[0019] Advantages of the present invention

[0020] No shielding is required, allowing the desired structure to be exposed directly into a photosensitive layer. Due to the use of multiple light sources, a wider spectrum can be selected, increasing the light output and, therefore, the achievable throughput. By tilting the focal plane (compared to the surface of the layer to be exposed) or by individually selecting the wavelengths, different depths can be exposed simultaneously with full resolution or different planes can be selectively exposed.

[0021] According to the invention, in particular, the device has an optical system having the following characteristics:

[0022] at least one light source for generating at least one light beam,

[0023] at least one micromirror device having a plurality of micromirrors, wherein each micromirror is configured to illuminate a pixel of an exposure pattern having a mirror intensity distribution,

[0024] The optical system is constructed in such a way that the mirror intensity distribution of overlapping adjacent micromirrors to form a pattern intensity distribution of the exposure pattern results in a sum of the mirror intensity distributions of the illuminated pixels of the exposure pattern.

[0025] The present invention describes a method and an apparatus for irradiating a photosensitive layer by means of a light beam (in particular a laser), which is guided through an optical system consisting of at least one micromirror device (DMD), preferably digital. Irradiation of the layer results in a physical and / or chemical change in the layer.

[0026] Specifically, embodiments according to the present invention may be conceivable as follows:

[0027] ·All regions

[0028] Continuous scanning

[0029] Step-by-step approach.

[0030] Maskless Exposure Unit “Maskless” is understood to mean imaging by a dynamic optical patterning system instead of a static template (mask, reticle).

[0031] A full-area maskless exposure unit is understood to mean a device having a DMD that can expose the entire area to be written, without any significant relative displacement between the layer to be exposed and the optical system. Therefore, according to the prior art of the present invention, only very small substrates can be exposed due to the limited size of current DMDs.

[0032] A scanning maskless exposure unit is understood to mean a device or a method in which the exposure field is smaller than the area to be exposed, so that a relative displacement between the optical system and the layer to be exposed occurs in order to expose the entire exposure field. In particular, this relative displacement occurs continuously along a path. The path is preferably:

[0033] · Zigzag · Located in a column that shifts to the next column and is reset to its original position when it reaches its destination,

[0034] Spiral,

[0035] Round,

[0036] Linear.

[0037] In particular, the paths mentioned can also be combined with one another. Thus, it is conceivable to initially use a rotary path for exposure, followed by a linear path that (in particular) leads through the center of the substrate or a plurality of initially independent writing paths that complement each other. The path is preferably meandering.

[0038] A step-by-step, maskless exposure unit is understood to mean an apparatus in which the exposure field is smaller than the area to be exposed, a relative displacement between the optical system and the layer to be exposed occurs step by step, and no exposure occurs between individual steps. The optical system only exposes the layer to be exposed when the optical system and the layer to be exposed are positioned in a well-defined position. Therefore, this embodiment involves exposing multiple sections of the layer to be exposed.

[0039] DMD Principle

[0040] A DMD allows for the deflection of (particularly, portions of) a broad (preferably parallel and / or non-scattering) primary light beam toward a target. Thus, a secondary optical exposure light beam with a spatial structure can be generated without the aid of shielding. In most cases, optical devices (particularly projection optics) are installed upstream and / or downstream of the DMD. These optical devices manipulate (particularly, scale) the primary exposure light beam that strikes the DMD and / or the secondary exposure light beam reflected by the DMD and, in particular in the case of lithography, can produce a size reduction of the DMD image. Consequently, the size reduction of the DMD image can be correspondingly reduced.

[0041] Specifically, the structural resolution of a DMD die that can be obtained is between 0.1 μm and 50 μm, preferably between 0.3 μm and 25 μm, and more preferably between 1 μm and 10 μm.

[0042] Primarily, for embodiments in which the individual exposure fields are smaller than the substrate, it is important that a seamless continuation of the structure to be produced occurs after a relative movement between the optical system and the layer to be exposed. In the case of stepwise scanning, this occurs in two independent directions, and in most cases in only one direction in the case of continuous scanning.

[0043] Optical system

[0044] Embodiments according to the present invention comprise at least one optical system, which may include multiple optical components of varying types. While at least one of the optical components is a DMD, the use of multiple DMDs constitutes a further embodiment according to the present invention. Specifically, the optical system comprises a single DMD, preferably at least two DMDs, and even more preferably at least four DMDs. The optical system itself can be used in one or more configurations in parallel on a substrate within an apparatus. The present invention also contemplates the parallel exposure of multiple substrates within the apparatus.

[0045] In addition, the optical system can include the following optical components:

[0046] Lighting optics

[0047] Specifically, coherent light sources

[0048] Laser light source

[0049] Laser diodes

[0050] Solid-state laser

[0051] Excimer laser

[0052] Specifically, incoherent laser sources

[0053] ■Specifically, gas discharge lamps

[0054] Mercury lamp

[0055] LED

[0056] ○Partially coherent light source

[0057] ○ Coherence change component

[0058] Deflection optics

[0059] ○DMD

[0060] Specifically, the reflector

[0061] ■Cold mirror

[0062] ■Heat reflector

[0063] ○ Specifically, the diffraction component

[0064] ■Prism

[0065] Beam splitter

[0066] Projection optics

[0067] Specifically, the lens

[0068] Fresnel lens

[0069] ■Diffractive lens

[0070] Convex lens

[0071] ·concave lens

[0072] Biconcave lens

[0073] Biconvex lens

[0074] Convex-concave lens

[0075] Meniscus lens

[0076] Cylindrical lens

[0077] Compound lens

[0078] Specifically, the reflector

[0079] ■Rotary reflector

[0080] ○Universal light-changing optical components

[0081] The light sources can be used continuously or in a pulsed manner and, in particular, can additionally be modulated internally or externally.

[0082] In particular, the maximum possible relative speed between the optical system and the layer to be exposed is limited by the maximum drive frequency of the DMD (i.e., the frequency at which the individual mirror elements of a DMD can be practically switched). The relative speed in a scanning system is also determined by the displacement and / or deflection optics and is, in particular, between 5 mm / s and 500 mm / s, preferably between 10 mm / s and 250 mm / s, more preferably between 15 mm / s and 200 mm / s, and most preferably between 25 mm / s and 100 mm / s.

[0083] A further important aspect of an embodiment according to the invention is to use a feed rate that is higher than the feed rate defined by the pattern size and the scanning frequency. Due to the corresponding selection of a higher feed rate, rows compensated by temporally later DMD exposure rows are omitted.

[0084] To avoid eliminating the exposure along the scanning direction, the exposure is interrupted and / or a local "deflection scanning" mechanism is used, which will keep the exposure position constant for a short time. In the following, the first possibility is considered first.

[0085] Specifically, to compensate for the dose loss caused by a higher feed rate, light output can be increased. This requires a greater (specifically) instantaneous output of the light source, which often conflicts with increased costs or physical / technical limitations. To address this issue, deflection scanning and dynamic splitting of a light source's output across multiple exposure units can be used as a more economical alternative.

[0086] During deflection scanning, the relative movement of the image pixels with respect to the substrate is minimized and interrupted by a short, rapid deflection (interleaving). Due to the small jump distance, this deflection can be generated by a mechanical-optical, electro-optical, magneto-optical or acousto-optical deflection or displacement unit.

[0087] During dynamic splitting of a light source, the light source's output is dynamically suppressed (e.g., cavity-dumped lasers, temperature-limited semiconductor light sources) and temporarily focused, or temporarily split between consumers by a distribution element (such as, for example, a rotating polygonal mirror, an electro-optical switch, or the like). Besides increasing the short-term output during a duty cycle, the goal is always to keep the long-term output constant.

[0088] Integrated measurement optics

[0089] The device preferably has a measurement optics system, in particular, which is integrated into the optical system. In particular, a beam splitter is preferably used to couple the light deflected from the layer to be exposed out of the optical path that is mounted on the DMD for exposure. The measurement optics system has several important tasks that do not necessarily all need to be performed simultaneously:

[0090] Alignment, used to align the exposure field with the structures present on the substrate or to reshape the exposure field,

[0091] Calibrate and check the writing head,

[0092] On-site inspection writing procedures,

[0093] Real-time correction (if dynamic changes occur in the relevant image substrate layer).

[0094] Alignment occurs relative to alignment marks already applied to the substrate or to intentionally applied or existing structures that serve as alignment marks for the structure to be re-exposed. Thus, larger areas can be exposed according to the invention because the optical system is always aligned and / or calibrated to the exposed structure.

[0095] A further important aspect of an embodiment of the invention is to calculate any substrate distortions caused by (in particular) the initial process and / or thermal influences by comparing the currently measured positions of the alignment marks with the desired positions and to adapt the image to be written to these distortions. These may also be higher order distortions.

[0096] In particular, in case of preventing seam artefacts (failures at the transition between adjacent pixels and / or adjacent exposure patterns), alignment and / or real-time correction plays an important role.

[0097] By capturing the structure of the exposure field during exposure (which can also be representative of surface noise) and comparing it with a capture of an adjacent exposure structure, a substrate offset can be determined by correlation or similar methods. This offset is applied to the DMD image as an error signal, allowing compensation down to the sub-pixel range.

[0098] Capturing / measuring preferably takes place along the same optical path (which is also used for exposure) so that a mechanical connection (in particular, mechanical fixing) can be achieved during capturing / measuring.

[0099] For capture / measurement, the optical signal (light from at least one light source) is preferably coupled out of the surface by an optical element (preferably a semitransparent mirror or a prism) and absorbed by a corresponding detector. The detector (or an evaluation system connected thereto) can then monitor the surface of the layer to be structured as it is exposed and / or written upon. The detector is preferably a camera, more preferably a CCD or CMOS camera. The camera image can capture one or more portions of the exposure field, a larger area, or one or more smaller sections. The exposure can have its own light source and can occur in the same illumination wavelength range (preferably) or in a different illumination wavelength range.

[0100] In a specific embodiment, a metrology optical element is also present on the bottom surface of the embodiment according to the present invention. This allows for the detection of alignment marks on the bottom surface of the substrate holder or substrate. The principle of bottom surface metrology of a substrate holder is similar to that disclosed in the embodiment disclosed in publication PCT / EP2016 / 070289. Measuring alignment marks on the bottom surface allows for the generation of structures that are aligned relative to one another on both sides.

[0101] Intensity distribution function

[0102] In a first particularly preferred embodiment according to the invention, an imaging / secondary optics (for influencing (in particular, scaling) the secondary exposure light reflected by the DMD) is constructed in such a way that a sharp image of the DMD mirror in the focal plane is not obtained, but a slightly less sharp image which also exposes the adjacent pixels is intentionally obtained. Thus, the optics can be constructed in a relatively inexpensive way and still improve the quality of the generated structure. The intensity distribution as a function of the ray diameter (intensity distribution) can correspond to any desired mathematical function. Closed-ended equations are used as an approximation to more complex real distributions. In particular, the main idea is:

[0103] Gaussian distribution,

[0104] Lorentzian distribution,

[0105] Cauchy distribution,

[0106] Convolution of different distribution functions.

[0107] In particular, the material of the photosensitive layer to be exposed has a defined (preferably nonlinear) reaction behavior that corresponds firstly to the cumulative light deposition and (in particular) secondly to the output and, therefore, to the exposure behavior. Thus, in the case of a local exposure gradient, an exposure edge is formed between a high dose and a low dose, which can fluctuate within defined or definable boundaries. The present method uses this approach and allows, by overlapping multiple exposure fields (in particular, with respect to individual micromirrors), to control the position of this exposure edge with a precision exceeding the pixel size.

[0108] For accurate positioning, the exposure power is calculated in advance and decomposed into a plurality of exposure elements (in particular, pixels) and / or different exposure steps. These exposure steps are temporally separated and / or have different lengths and, taken together, result in a target exposure profile at the pattern level (pattern intensity profile) and / or a target exposure profile at the substrate level (substrate intensity profile). Correlated and / or incoherent overlaps of the individual distribution functions (mirror intensity profile and / or pattern intensity profile) and / or image generation dynamics are preferably taken into account.

[0109] The result is a structuring of the exposure boundary, which is primarily defined as the sum of the exposure processes, but secondarily, in the dynamic case, also takes into account the two-dimensional form and the three-dimensional shape of the material response to be modeled or determined empirically. The terms "overlap" and "interference" will be explained in more detail below.

[0110] Multiple exposures of individual partial areas can also occur simultaneously and with a time delay. As long as the changes in the exposed material do not depend on the exposure power but only on the flux (the accumulated area dose), and no mechanical changes occur (such as those caused by heating or misalignment due to vibrations or displacements), then overlapping the exposure fields (by simple addition) will lead to the same result as a single exposure to one light source.

[0111] In cases where non-linear relationships occur, these can be compensated by corresponding calculations or tests and subsequent adjustments to the partial exposures. In the case of random fluctuations, overlap leads to undesirable blurring or fluctuations, which manifest as image errors (eg, blur).

[0112] In the case of a reproducible or precalculated overlap, edge roughness, jitter and other undesirable effects can be minimized and a clean stitching of the exposure fields can be guaranteed. Even short-term exposure position fluctuations can be compensated by the method according to the invention.

[0113] When exposing multiple light paths, interference effects occur in optical devices if the partial radiation sources exhibit exactly or nearly identical temporal and spatial behavior due to their coherence. The overlap of the electromagnetic component fields is not simply averaged out, but also produces constructive and destructive overlaps in photosensitive surfaces and volumes that are slower than those in the THz range. These effects most often occur when emissions from the same source overlap, where the duration of the coherence time is similar—hence, the high-frequency oscillation behavior is dependent on one another. Photochemical interference effects can also occur in multiple exposures, where successive exposure steps react to one another. These are taken into account in the control.

[0114] Prevent exposure failure at high speeds

[0115] In a second improved embodiment, an optimization of the data path is implemented. A fundamental problem during the maskless exposure step is that very expensive and complex calculations (such as rasterization) are performed therein and a very large amount of data is stored and transmitted. The data stored in the computer are synchronized with the relative movement between the optical system and the layer to be exposed or the DMD, or with the substrate. The structural data to be imaged in or on the layer to be exposed are stored on a computer. This structural data defines how the mirrors defining the DMD are switched according to position in order to change the exposure light in such a way that the desired pattern falls on the layer to be exposed. In the case of a full-area or step-by-step embodiment, the optical system (and therefore the DMD) is always at a defined (in particular, fixed) position. Therefore, in this case, a dynamic correlation between position and structural data is not necessarily generated.

[0116] However, if a (preferred) scanning embodiment is used, a continuous exposure that varies according to position occurs, wherein new data is continuously supplied to the DMD during the relative movement to control the position-dependent micromirrors. Therefore, the data for mirror control must be sent to the DMD quickly enough. Because calculating the mirror matrix is ​​expensive, according to an advantageous embodiment, the various calculations are separated. In particular, a distinction is made between time-critical and non-time-critical calculations.

[0117] According to the invention, time-critical calculations are understood to mean all calculations which have to be performed quickly enough so that the data reaches the DMD before it changes its relative position with respect to the layer to be exposed.

[0118] Specifically, time-critical computations are:

[0119] Specifically, image computing

[0120] ○DMD control

[0121] Specifically, sensor measurements and feedback calculations

[0122] ○Scan and adjust the current writing position

[0123] Decompression

[0124] ○ Specifically, information from and / or to DMD

[0125] These calculations require relatively high computational speeds, making hardware calculations preferable to software calculations. The hardware components that can be used for these calculations are:

[0126] FPGA (Field Programmable Gate Array)

[0127] ASIC (Application Specific Integrated Circuit)

[0128] GPU (graphics processing unit)

[0129] Signal processor (DSP digital signal processor)

[0130] Non-time-critical calculations are those that only slightly change during the exposure process or are not process-critical. Specifically:

[0131] Convert vector data into pixel data (rasterization),

[0132] Adjust the structure size

[0133] Compensate for large-area distortion

[0134] Insert wafer-specific data or die-specific data (e.g. serial number)

[0135] Cut the data into strips for each write head

[0136] Rasterized vector data

[0137] These calculations are often very complex, involve a very large range of data in one calculation step (in particular, global adjustments), and / or (in particular) cannot be efficiently implemented by hardware.

[0138] · implemented in at least one thread of the same computer or

[0139] · Implemented in parallel in at least one thread of at least one other computer

[0140] In this case, the threads can use the CPU and / or GPU resources of the graphics adapter.

[0141] Communication between the computer and the DMD occurs via any desired interface, specifically:

[0142] Wired communication

[0143] ○USB,

[0144] ○Ethernet network,

[0145] ○DisplayPort.

[0146] A first improved embodiment is based on the fact that the hardware used for time-critical calculations has access to a memory that is large enough to store and retrieve at least two exposed segments of the layer to be exposed (specifically, partial segments of the exposure path, preferably strips, and more preferably parallel strips). While one exposed segment is being written from the buffer / memory, the second exposed segment is transferred from the computer to the unit used for calculating the time-critical task. When all the same conditions are present in the memory, the exposure process for a segment to be exposed begins for the first time. Before the first strip has completed its exposure process, the second strip is essentially completely loaded into the memory. This principle is repeated for the following strips. This effectively prevents a strip from running out of data for the time-critical calculation and causing an exposure failure.

[0147] Real-time correction of written data

[0148] In a third improved embodiment, mechanical failures are at least partially compensated by optical components. If the device according to the present invention exposes a continuous structure into the layer to be exposed in a scanning process, it is advantageous to better set or provide the positioning accuracy of the substrate holder compared to overlap. All position errors come from imperfectly completed mechanical components, games and tolerances, imperfect motor control, etc. It is relatively complicated to reduce errors by mechanical methods. According to the design of the present invention, larger position errors such as overlap can be allowed. In this case, measurement technology is used to detect the position error and the DMD image is offset (in particular, in real time) accordingly. The position error is compensated in a manner according to the present invention so that the position error is less than the overlap specification at any time point during the exposure process. In particular, the ratio between overlap and uncorrected position error is less than 1, preferably less than 10, and more preferably less than 100.

[0149] According to the present invention, errors perpendicular to or along the direction of relative movement can be compensated.

[0150] In the event of errors perpendicular to the relative motion, a slightly narrower exposure stripe is used, but the DMD is designed to expose a wider exposure stripe. Therefore, the extra exposure areas on the left and right serve as a buffer. In the event of positional deviation of the substrate holder, the exposure stripe is shifted to the left or right in real time, ensuring that data is exposed at the correct location on the layer to be exposed, even with positional errors.

[0151] Errors in the direction of relative movement are similarly compensated. If the substrate holder moves too slowly, the scroll speed (row cycle) is adjusted (specifically) and the intensity is compensated by exposure control. If the substrate holder moves too quickly, the position of the exposure image can also be adjusted by the scroll speed (row cycle). However, dose correction by adjusting the exposure time is only possible if the exposure does not occur at maximum intensity.

[0152] The invention allows the use of an inexpensive mechanism and nevertheless achieves a high positioning accuracy.

[0153] Strip overlap (stitching)

[0154] In a fourth improved embodiment, the layer to be exposed is exposed in such a way that the calculated exposure segments (in particular, strips) overlap. Preferably, the areas at the edges of the strips are exposed twice. To prevent overexposure or underexposure, the intensity is changed or formed so that it can be changed according to the position of the optical system (in particular, the DMD). Preferably, these intensity distributions are then added together to obtain a constant or at least more uniform intensity distribution. The overlap of the strips can be regarded as seams, which should be exposed in such a way that, ideally, they cannot be distinguished from a full-area exposure. A more precise description occurs in Figures 6a to Figure 6c The stripe overlap according to the present invention is produced not only by utilizing the intensity drop at the edge of an exposed stripe, but also by using dynamic illumination control in a targeted manner, which allows the intensity in the edge region of the exposed stripe to drop continuously. Therefore, in particular, the present invention preferably enables seam control by targeted intensity control.

[0155] Deflectometry scan

[0156] In a fifth improved embodiment, the exposure process occurs such that in a first step, the optical system or DMD and the substrate (specifically, synchronously, preferably simultaneously) move in the same direction, and during this process step, the light source is switched on as needed. In a subsequent second process step, the optical system (or DMD) is displaced in a direction opposite to the direction of movement of the substrate holder (preferably at a relatively high speed). Specifically, no exposure occurs during this process step. Following this simultaneous movement, a partial return movement of the optical system is then performed along the entire row (specifically, for each additional DMD row). This synchronized (specifically, collinear) relative movement between the optical system and substrate results in a quasi-static exposure. Consequently, washout of exposure due to the relative movement during scanning is reduced (preferably completely suppressed), resulting in better imaging.

[0157] In a further improved embodiment, the exposure process occurs in such a way that, in a first step, a relative movement between the optical system and the layer to be exposed occurs along a first direction. In a second process step (particularly, running simultaneously), the optical system (or DMD) is displaced along a second direction (deviation from the first direction) (particularly, arranged perpendicular to the first direction). Preferably, this displacement occurs in steps smaller than the imaging width of an individual pixel, thus producing a relatively fine positioning pattern of the image points. The simultaneous movement following the lateral displacement of the optical system allows for increased positioning accuracy or overlap. Due to the synchronized (particularly, non-collinear) relative displacement between the optical system and the substrate, the loss of exposure during scanning due to the relative movement is reduced (preferably completely suppressed), and a better image is obtained.

[0158] In an embodiment according to the present invention, all components (specifically, optical components) used to generate the image are regulated by piezoelectric elements. Specifically, electro-optical, bio-optical, or mechano-optical components can be used. The image can be shifted in the x, y, and / or z directions by control. Multiple components can also be used, which can implement (specifically) translational and / or rotational movement of the image. The image can be tracked at a speed corresponding to the scanning speed.

[0159] Simultaneous exposure of different structures on different focal planes

[0160] In a sixth improved and preferred embodiment, the focal plane is tilted relative to the layer to be exposed. During an exposure, the position of the focal plane and the depth of focus are very important to the quality of the imaged structure. The focal plane can be tilted in several ways.

[0161] In a first development of the sixth embodiment, the focal plane is changed by mechanically tilting the entire DMD. This embodiment is the worst.

[0162] In a second preferred development of the sixth embodiment, the focal plane is influenced by objectively changing optical components connected upstream and / or downstream of the DMD. The tilt of the focal plane is influenced by the optical components. Preferably, the focal plane is statically set once, and different regions of the DMD are used to expose different depths of the layer to be exposed.

[0163] In a third development of the sixth embodiment according to the invention, a light source of a plurality of different wavelengths and / or a light source having a broadband wavelength spectrum is used to generate a plurality of (in particular, continuous) focal planes in (or through) the layer to be exposed.

[0164] In this embodiment, the layer to be exposed is preferably formed from a material, in particular a polymer, which is sensitive to the corresponding radiation across the entire wavelength range.

[0165] Dynamic Exposure Control in Grayscale Lithography

[0166] In a seventh improved embodiment, the intensity at each position is controlled in a targeted manner by one of the following methods. Thus, overexposure and / or underexposure can be compensated. In addition, low-quality structures can be improved and exposure gradients can be generated. By targeted control of the intensity at each position, (in particular)

[0167] 3D structure

[0168] Grayscale lithography and / or

[0169] ·Optical proximity correction.

[0170] A crucial aspect of using a DMD is ensuring that the intensity of the photons incident on the layer to be exposed is distributed in a spatially accurate manner. Since no light source is a perfect spotlight, no light source has a uniform intensity distribution. Consequently, the light incident on the DMD is also non-uniform. It is preferable to homogenize the light using optical components within the optical system before it is incident on the DMD.

[0171] According to the invention, not only is the uniformity of the light source modified, but the DMD (specifically, its micromirrors) is also adjusted for light with the correct intensity distribution deflected onto the layer to be exposed. There are several advantageous measures for correctly controlling a complex spatial intensity distribution.

[0172] Specifically, the light source has an output between 0.01 Watt and 1000 Watt, preferably between 0.1 Watt and 500 Watt, more preferably between 1 Watt and 250 Watt, most preferably between 5 Watt and 100 Watt, and most preferably between 9 Watt and 13 Watt.

[0173] Press W / m 2 The intensity can be specified. The intensity of the radiation focused onto a unit area by optical components can be easily calculated. The intensity of the light source can preferably be adjusted very precisely. The intensity can be varied by changing the output of the light source, by varying the exposure duration, and / or by optical components in the optical system. Thus, according to the present invention, light of varying intensities can be directed onto the DMD within a well-defined time period. By controlling a corresponding reflector, individual points of the layer to be exposed can be irradiated with defined intensities. Surrounding points of the layer to be exposed can be illuminated with a different intensity.

[0174] According to the present invention, it is possible to expose a layer to be exposed that is resolved in a targeted, point-wise manner (specifically, associated with individual pixels). By relatively moving the optical system and the layer to be exposed, it is possible to advance to each position several times, thereby exposing each pixel to be exposed multiple times. By using a measurement system and targeted analysis of the surface quality, the multiple exposures can be controlled in such a way that the most uniform exposure down to the pixel level is achieved.

[0175] Therefore, on the one hand, intensity non-uniformities from an original light source can be compensated as long as a uniform pixel exposure is desired, and on the other hand, exposure doses that differ in an address-based manner can be introduced into the layer to be exposed.

[0176] Furthermore, the aforementioned embodiments according to the present invention can be used to overlap the exposure segments (in particular, stripes) to be exposed. This overlap allows for multiple exposures of individual pixels. Starting from the exposure counts for each pixel, the desired intensity component (at which the pixel is exposed) can be calculated for each individual exposure process.

[0177] If a structure with an intensity gradient is imaged, the invention determines in particular how often and with what intensity a pixel should be exposed so that in n repetitions each pixel is already charged with the determined absolute intensity at the end of the exposure process.

[0178] In a further eighth embodiment of anisotropic and / or anamorphic imaging optics for improving overlay error and / or motion blur, the horizontal and / or vertical exposure pattern grid lines of the exposure pattern are imaged differently (specifically, non-quadratically) by optical imaging, thereby setting different exposure pattern resolutions in the vertical and horizontal directions. Exposure calculation / control is compensated by deviation.

[0179] In a further embodiment, the imaging axes or the exposure pattern grid lines are not arranged orthogonally, but rather in an obliquely extending manner. Using this (particularly affinely distorted) projection (particularly a shear) allows for simple calculation of the radiation position and linear guidance for an exact layout of illumination points below the raster resolution (sub-pixel accuracy) to obtain precise information about the exposure edge.

[0180] In a further embodiment according to the invention, the horizontal and / or vertical exposure pattern grid lines of the exposure pattern in the vertical and / or horizontal direction are not realized equidistantly.

[0181] Different exposure patterns can be generated from a uniform isotropic image of the DMD by optical components connected upstream and / or downstream of the DMD, and / or they are a direct result of an anisotropic and / or inhomogeneous structure of the DMD.

[0182] Furthermore, several possibilities are shown for generating a corresponding projection according to the invention (in particular, a shearing of the exposure pattern).

[0183] In a first possible embodiment according to the present invention, at least one cylindrical lens having a cylindrical axis is used as the imaging optical element to effect a change in the exposure pattern. Specifically, exactly two cylindrical lenses are used. The cylindrical axes of the cylindrical lenses are preferably parallel to the surface to be exposed. To achieve a shearing according to the present invention, an angle of less than 90° (preferably less than 70°, more preferably less than 50°, and most preferably less than 20°) is provided between the two cylindrical axes. However, the optimal angle in each case depends on the shearing angle to be produced.

[0184] In a further embodiment according to the invention, the optical system consists of only a single so-called compound lens. A compound lens is understood to mean a lens whose surfaces are ground in such a way that the optical properties are identical to those obtained by combining two lenses.

[0185] Thus, the above-specified embodiments can be achieved by both regular and irregular irradiation of the substrate. In the specific case where the exposure repetition rate is regular but not entirely aligned with the travel speed, an exposure structure specifically targeted at the current writing position is activated. Consequently, the non-uniform displacement of the sub-pixel layout influences the travel direction, resulting in improved layout accuracy and increased edge roughness.

[0186] A combination of the collective and / or temporal shifts described above will yield sub-pixel resolution in all directions and reduce sensitivity to errors (compared to failures of individual exposure components). Understanding the distortions caused by imaging errors and / or artifacts is necessary to characterize the correct exposure dose distribution. Linearly distorted or rotated images offer the advantages of simpler computations and easier light source control.

[0187] Reduce motion blur

[0188] In a further ninth embodiment according to the invention, the relative speed and / or movement between the optical system and the layer to be exposed is varied in such a way that a plurality of pixels overlap within a pixel size. This overlap can be interpreted as a long exposure of a moving object. Thus, a pixel elimination occurs in the direction of relative movement. Due to the decision of when to write or not write one of these pixels, the pixel size along the direction of relative movement can be set in a targeted manner. For clarity, see Figures 8a to 8b or the corresponding descriptions of those figures.

[0189] In other words, the two exposure patterns sequentially illuminated one after another are displaced or moved to have a relative displacement between the micromirror device and the pixel photosensitive layer that is smaller than a pixel width (preferably smaller than half a pixel width, more preferably smaller than a quarter of a pixel width).

[0190] If the optical system shrinks or expands significantly less along the scanning direction than along the direction perpendicular to the scanning direction, the motion blurring effect due to the limited exposure time can be partially compensated. This allows for isotropic imaging. Compression along the direction of travel does not reduce motion blur per se, but only reduces the total range of exposure points in the direction of travel.

[0191] The embodiments and procedures according to the present invention mentioned may be combined with each other as needed, but they are described separately. Whenever method features are described, they should also be considered to be disclosed as device features, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0192] Further advantages, features and details of the invention will be obtained from the following description of preferred exemplary embodiments and on the basis of the drawings. In the drawings:

[0193] Figure 1 A first embodiment of the device according to the present invention is shown.

[0194] Figure 2 A second embodiment of the device according to the invention is shown.

[0195] Figure 3 A third embodiment of the device according to the present invention is shown.

[0196] Figure 4a shows a schematic depiction (not true to scale) of a DMD (micromirror device) having an enlarged portion of a section containing a micromirror in a first position, Figure 4b shows a schematic depiction (not true to scale) of a DMD (micromirror device) having an enlarged portion of a section containing a micromirror in a second position, Figure 5a A schematic drawing showing a plan view of a first exposure section of a layer to be exposed (not true to scale),

[0197] Figure 5b A schematic drawing (not true to scale) showing a plan view of a second exposure section of a layer to be exposed, the second exposure section being slightly offset relative to the first exposure section,

[0198] FIG6 a shows a schematic illustration (not true to scale) of a plan view of a substrate having a first exposure section,

[0199] Figure 6b a schematic drawing (not true to scale) showing a plan view of a substrate having a second exposure section,

[0200] Figure 6c a schematic drawing (not true to scale) showing a plan view of a substrate with overlapping first and second exposure sections,

[0201] Figure 7a A schematic drawing (not true to scale) showing a further embodiment of the device according to the invention, Figure 7b A schematic drawing (not true to scale) showing a further embodiment of the device according to the invention, Figure 7c A schematic drawing (not true to scale) showing a further embodiment of the device according to the invention, Figure 8a a schematic drawing (not true to scale) showing a plan view of a further exposed section of a layer to be exposed according to a first embodiment of the method according to the invention,

[0202] Figure 8b a schematic drawing (not true to scale) showing a plan view of a further exposed section of a layer to be exposed according to a second embodiment of the method according to the invention,

[0203] Figure 9a A schematic diagram showing a first embodiment of an exposure pattern according to the present invention (not true to scale), Figure 9b A schematic diagram showing a first embodiment of an exposure pattern according to the present invention (not true to scale),

[0204] Figure 10 A schematic diagram showing the intensity distribution of two adjacent pixels with three different intensities,

[0205] Figure 11 A schematic diagram showing an exposure pattern having a plurality of exposure pixels, and

[0206] Figure 12 A schematic diagram showing an exposure pattern distorted by optical components.

[0207] In the drawings, the same reference numerals are used to mark the same components or components with the same function. DETAILED DESCRIPTION

[0208] Figure 1 A first embodiment is shown consisting of an optical system 8 having at least one light source 7 and at least one DMD 1 (micromirror device), a substrate holder 11. The substrate holder 11 can be moved relative to a coordinate system K3.

[0209] A substrate 10 is fixed on a substrate holder 11 using a fixing member 13 , on which a photosensitive layer 9 made of an exposable material is located. The photosensitive layer 9 is exposed by the apparatus.

[0210] The origin of the coordinate system K2 of a sample fixation (ie fixed to the substrate 10 or the layer 9 to be exposed) is preferably placed at the center of the surface 9 o of the layer 9 .

[0211] Light 6 (original light) emitted by light source 7 and passing through a plurality of optical components (not shown) on its way to DMD 1 is converted into structured light 6' (secondary light) by DMD 1. It may pass through a plurality of optical components (not shown) on its way to layer 9.

[0212] A detector 19 (in particular, a camera, more preferably a CCD or CMOS camera) can capture and / or measure the surface 9o of the layer 9 to be exposed via a semi-transparent mirror 14". The measured structure is preferably used for direct control of the method and / or calibration of the device. For the sake of clarity, the illustration of these measuring components may be omitted in the further description of the drawings and in the drawings. However, the measuring components according to the present invention can be used in the various embodiments according to the present invention mentioned.

[0213] Figure 2 A second embodiment is shown in which the optical system 8 is equipped with two light sources 7, 7'. The two light sources 7, 7' emit light rays 6. One of the light rays 6 is deflected by a reflector 14 onto a beam splitter 14' and combined with the light 6 of the second light source 7' by the same reflector.

[0214] The combined light 6 is guided onto the DMD 1 and converted by the same DMD into a structured light 6 ′. The structured light may then pass through a plurality of optical components (not shown) on the way to the layer 9 .

[0215] According to a particular independent aspect of the invention, the radiation intensity, wavelength, correlation length and, if appropriate, other properties or parameters of the two light sources 7 can be different, so that a laser beam 6 can be generated using a plurality of different optical parameters.

[0216] According to the invention, in particular, more than 2, in particular more than 5, more preferably more than 10, and most preferably more than 20 light sources 7, 7' can be used. Each light source can preferably be an LED field or an LD (laser diode) field.

[0217] Figure 3 A third embodiment is shown consisting of an optical system 8 having at least one light source 7 and two DMDs 1 .

[0218] A light beam 6 is emitted by a light source 7 and split by a beam splitter 14'. A first split light beam 6.1 is modified by a first DMD 1 to form a first modified light beam 6.1'. The first modified light beam 6.1' is used to expose the layer 9. The second split light beam 6.2 is deflected by a reflector 14 to a second DMD 1 and transferred to the layer 9 as a second modified light beam 6.2'. Preferably, the second modified light beam 6.2' is used instead of the first modified light beam 6.1' to expose a different position of the layer 9 to be exposed. The light beams mentioned above may pass through a plurality of optical components (not shown in the figure).

[0219] In a particular embodiment of the present invention, at least two DMDs 1 are used, by which layer 9 can be exposed simultaneously at two different locations, preferably using a single (particularly) combined beam to load the DMDs. This results in a larger exposure area (particularly an exposure stripe) and thus in an increased throughput.

[0220] Figure 4a A DMD 1 is shown with a mirror 2. An enlarged illustration of a portion of mirror 2 shows a plurality (16) of mirrors 3. The mirrors are arranged in a non-tilted alignment, designated as the initial position. A coordinate system K1 is assigned to DMD 1. The z-axis of K1 (i.e., K1z) is perpendicular to mirror 2, and the x and y coordinates are parallel to the mirror edges 2kx and 2ky of mirror 2 and define a mirror plane.

[0221] Figure 4b The same DMD 1 is shown with one of the mirrors 3 arranged in a tilted position or a position rotated about the x-axis. As a result, a portion of the light 6 impinging on the tilted mirror 3 is reflected in a direction that is different from the direction of reflection of the portion of the light 6 reflected by the non-tilted mirror 3.

[0222] Figure 5a A schematic diagram of a mirror 2 is shown, which in each case has a central (in particular, strip-shaped) writing area 4 and two (preferably parallel) buffer areas 5 at the edges (which are adjacent to the writing area 4).

[0223] Different from the reflector 3, the figure shows pixels 23 of an exposure pattern 24 reflected by the mirror 2, which correspond to the formed structures 12 at the position K2y=12 on the layer 9 to be exposed (which can be changed by the optical components between the DMD 1 and the layer 9 to be exposed).

[0224] According to an advantageous embodiment of the invention, only the mirrors 3 arranged in the writing area 4 are used for exposure, so that the buffer area 5 forms a writing buffer, as explained below. The center line D extends through the fixed center point O of the K2x axis of the sample coordinate system.

[0225] Figure 5b The same DMD 1 is shown after a relative shift of 0.5 au in the K2y direction. Thus, DMD 1 is located at K2y = 12.5 au. It can also be seen that a relative shift of approximately 2 au has occurred in the K2x direction. This relative shift is desirable and may result, for example, from a fault during installation. It is clearly visible how structure 12 is shifted to the left relative to DMD coordinate system K1 in order to correctly expose it in coordinate system K2y. Therefore, a write buffer is used.

[0226] Therefore, targeted programming of the DMD will allow correction of mechanical faults. Thus, the substrate holder 9 does not move the substrate 10 (and therefore the layer 9) along a perfectly straight line in the K2y direction, but rather there is a slight displacement towards K2x during the movement along the K2y direction.

[0227] According to the present invention (an independent aspect of the present invention), the mechanism of substrate holder 9 is preferably not used to correct for malfunctions. Instead, writing area 4 and buffer area 5 are programmed / electrically controlled in a manner that correspondingly shifts structure 12 to be exposed (here, in the negative K1x direction). Thus, the electronics and / or mechanism of DMD 1 compensate for writing errors (here, mechanical malfunctions of substrate holder 11).

[0228] 6a shows a plan view of a layer 9 exposed along a first strip 15. The strip 15 corresponds to the area of ​​the layer 9 exposed by the writing area 4 of the DMD 1 after the DMD 1 has been moved relative to the exposed layer 9 in the direction K2y.

[0229] In a region between the intensity variation regions 161 , 16r of the strip 15 , the illuminated pixel 23 is illuminated with an intensity that is as uniform as possible.

[0230] In contrast, the illuminated pixels 23 in the intensity variation regions 161, 16r are controlled in such a way that the intensity of the reflected light 6' from the writing region 4 in the direction of the edge of the DMD 1 decreases (in particular, continuously) (preferably in direct proportion to the distance from the writing region 4). The marks correspond to a pattern intensity distribution (intensity / position) that varies according to position (from which the intensity curve can be read). Thus, the intensity used to expose the layer 9 has a maximum in the region of the strip 15 and normally decreases (preferably smoothly and / or linearly) laterally to zero.

[0231] Figure 6b Shows something like Figure 7a6a , in particular, it is about a second stripe 15' that is exposed next to the first stripe 15. It is shifted to the right relative to the first stripe 15 so that the intensity change area 16r on the right side of FIG6a is aligned with Figure 7b Pixels 23 are connected to the right intensity distribution region 16r in the same manner as in the left intensity variation region 161′, wherein the intensities of corresponding pixels 23 are summed to obtain a pixel intensity corresponding to the intensity in the stripe 15.

[0232] Figure 6c A plan view is shown in which the intensity variation region 16r of the first strip 15 and the intensity variation region 16l' of the second strip 15' overlap, so that a constant intensity distribution is obtained. Therefore, exposure occurs uniformly as the intensity of the first strip 15 and the intensity of the second strip 15' are added together.

[0233] Figure 7a A magnified section of an embodiment of the present invention is shown, showing a DMD 1, the optical paths of primary light 6 and secondary light 6', and a layer 9 to be exposed. Here, primary light 6 and secondary light 6 are symbolically represented only by optical paths 6, 6' and are preferably large enough to illuminate the entire DMD 1. Secondary light 6' is perpendicular to layer 9 to be exposed. Specifically, focal plane 17 is parallel to surface 9o (preferably located on surface 9o). A depth of field range 18 represents the depth within which a clear image of a pixel 23 can occur.

[0234] Figure 7b An enlarged section according to a preferred embodiment of the present invention is shown. Figure 7a The second light ray 6' is reflected at an angle α onto the layer 9 to be exposed. Therefore, the focal plane 17 intersects the layer 9 to be exposed at an angle α. On the left side, it is outside the layer 9 to be exposed, while on the right side, it is within the layer 9 to be exposed. Therefore, the depth of field 18 penetrates deeper into the layer 9 on the right side and can be used to produce a clear three-dimensional structure in the recess without moving the focal plane 17 in the K2z direction by moving the DMD 1.

[0235] Specifically, the need to shift DMD 1 in the K2z direction to more clearly image structures at greater depths can be avoided by tilting DMD 1. Thus, dynamic displacement of the exposure area on DMD 1 allows for a clear exposure of a target at a corresponding depth. A significant advantage over multiple exposures is that structures can be generated with high precision in all spatial directions without mechanical errors.

[0236] Figure 7c An enlarged section according to a preferred embodiment of the present invention is shown. Figure 7aand / or Figure 7b The embodiment of the present invention is modified in that an optical element (not shown) located between the DMD 1 and the layer to be exposed 9 deflects the secondary light 6' in such a way that the focal plane 17 is tilted at an angle α relative to the substrate surface 9o.

[0237] Figure 8a A plan view of a portion of layer 9 to be exposed is shown. DMD 1 illuminates a pixel 23 (the smallest unit of an exposure pattern 24) along a length l. This is due to relative movement between DMD 1 (not shown) and layer 9 to be exposed. By illuminating pixel 23, layer 9 is exposed over an area of ​​width b throughout the entire travel along length l. The exposed area corresponds to pixel 23, with the intensity of the exposure controlled by the illumination intensity. In the event of overlap, the intensities in the overlapping area are summed.

[0238] Exposures occur from K2y position 0 upward to K2y position 3. A dropout occurs along the relative movement direction because multiple exposures occur during the relative movement in the range from about -2 to about 5. The intensity distributions of pixels 23 overlap and a stronger intensity increase along path 1 occurs.

[0239] Figure 8b exhibit Figure 8a An alternative embodiment wherein Figure 8a The difference is that since the corresponding mirror 3 of the DMD 1 (not shown in the figure) first starts the exposure from K2y position 1 and the exposure ends at K2y position 2, a smaller length l' is produced. Therefore, the resolution along the K2y direction can be increased by targeted control of the mirror 3 (in particular, when the latter is switched on later or switched off earlier). Therefore, in practice, the start of the exposure of the pixel 23 is delayed by 33.33% and ends 33.33% earlier. Since each light ray has an intensity distribution that deviates from a step-by-step shape, the pixel 23 cannot be exposed quadratically. The exposure patterns 24, 24', 24", 24'" are drawn as reference lines, which we can imagine to be located above the layer 9 to be exposed. These patterns preferably correspond to the size of the pixel 23.

[0240] Figure 9a A first exposure pattern 24 is shown that is less preferred according to the present invention and has equally spaced exposure pattern grid lines 27 in two mutually orthogonal directions K2x and K2y. Therefore, the exposure pattern 24 is isotropic and uniform in both directions K2x and K2y.

[0241] Figure 9bA second preferred exposure pattern 24' according to the present invention is shown having a separate spacing for each direction, specifically, with respect to that direction, the spacing being equidistant between exposure pattern grid lines 27. Thus, exposure pattern 24' is anisotropic but uniform in each of directions K2x and K2y.

[0242] It is also conceivable that exposure takes place at the intersections 25 of the exposure pattern grid lines and / or at partially exposed pattern areas 26 and not within individual pattern areas.

[0243] In particular, the different exposure patterns 24, 24', 24", 24'" can be generated / modified by optical components (not shown) installed upstream and / or downstream of the DMD 1 (not shown). The DMD 1 (not shown) is preferably isotropic and uniform, wherein the (particularly downstream) optical components (not shown) are configured to influence an anisotropic and / or uniform imaging of the DMD.

[0244] Figure 10 A schematic cross-sectional diagram shows two mirrors 3 and mirror intensity distributions 22, 22', 22" (in particular, Gaussian distributions) and pixels 23, 23', 23" generated by these intensity distributions 22, 22', 22", which are achieved by three different parameter sets and / or structural changes of the mirror 3. It can be seen that the intensity distributions with gradually increasing parameters of the characteristic distribution function (in particular, the full width at half maximum (FWHM) FWHM, FWHM', FWHM") overlap even more highly, so that two adjacent pixels 23, 23', 23" are eliminated more effectively. In the case of the most highly overlapping pixel 23", the result is a very uniform exposure pattern.

[0245] Figure 11 A schematic plan view (not true to scale) of a plurality of pixels 23 on a 5x5 exposure pattern 24 is shown. A pattern 28 is visible, which is illuminated by the target connection of the corresponding mirror 3. The mirror intensity distribution of the mirror 3 is very sharp, so that the intensity maximum is clearly visible, and the intensity drop-off is very obvious, so that the intensity distribution of each mirror 3 (not shown in the figure) is very highly restricted to the assigned partial exposure pattern area 26. In particular, in a preferred embodiment according to the invention, the mirror intensity distribution partially overlaps outside the partial exposure pattern area 26, such as is achieved according to Figure 10 The case of pixel 23".

[0246] Figure 12A schematic plan view (not to scale) of an exposure pattern 24" is shown which is distorted by (in particular) optical components of the optical system 8. Part of the light reflected by the mirror 3 of the DMD 1 is reflected orthogonally onto the layer 9 to be exposed by the optical components, but a distortion occurs (preferably only) in the K2x-K2y plane. An exposure pattern 24" can be generated by the method according to the invention, which will lead to an increase in the overlap according to the invention. In this embodiment, the DMD 1 is preferably not tilted, but instead the original image of the DMD 1 is affinely distorted to influence the tilt of the exposure pattern 24".

[0247]

Explanation of symbols

[0248] 1 DMD

[0249] 2 Mirror

[0250] 2kx Specular Edge

[0251] 2ky Mirror Edge

[0252] 3 reflectors

[0253] 4 Write area

[0254] 5 Buffer Zone

[0255] 6 Light

[0256] 6' Structured Light

[0257] 6.1 First Splitting Ray

[0258] 6.1' First Change Ray

[0259] 6.2 Second Splitting Ray

[0260] 6.2' Second Change Ray

[0261] 7 / 7' light source

[0262] 8 Optical System

[0263] 9 Photosensitive layer

[0264] 9o surface

[0265] 10 substrate

[0266] 11 Substrate holder

[0267] 12 Structure

[0268] 13 Fixed components

[0269] 14 Reflector

[0270] 14' beam splitter

[0271] 14” semi-transparent mirror

[0272] 15 First Strip

[0273] 15' second strip

[0274] 16l Intensity variation area

[0275] 16l' Left intensity change area

[0276] 16r Intensity change area

[0277] 17 Focal plane

[0278] 18 Depth of Field Range

[0279] 19 Detector

[0280] 22 / 22' / 22" strength distribution

[0281] 23 / 23' / 23" pixels

[0282] 24 / 24' / 24” / 24”' exposure pattern

[0283] 25 exposure pattern grid line intersections

[0284] 26 Partially exposed pattern area

[0285] 27 exposure pattern grid lines

[0286] 28 patterns

[0287] b width

[0288] D Centerline

[0289] FWHM Full Width

[0290] FWHM' Full Width At Half Manifold

[0291] FWHM” Full Width

[0292] K1 coordinate system

[0293] K2 coordinate system

[0294] K3 coordinate system

[0295] l / l' length

Claims

1. A method for exposing a photosensitive layer (9) using an optical system (8), wherein at least one light ray (6, 6') is generated by at least one light source (7) in the optical system (8) and a plurality of pixels (23) of an exposure pattern (24, 24', 24", 24'") are illuminated by at least one micromirror device (1) in the optical system (8), the at least one micromirror device (1) having a plurality of micromirrors (3) with a mirror intensity distribution (22, 22', 22"), characterized in that Different structures on different focal planes are exposed simultaneously by tilting the focal plane compared to the surface of the layer to be exposed, and multiple focal planes are generated using a light source using multiple different wavelengths and / or a light source with a broadband wavelength spectrum.

2. The method according to claim 1, wherein In order to give a pattern intensity distribution of the exposure pattern (24, 24', 24", 24'"), the mirror intensity distribution (22, 22', 22") of the micromirror (3) is superimposed as a sum of the mirror intensity distributions (22, 22', 22") of each illuminated pixel (23) of the exposure pattern (24, 24', 24", 24'").

3. The method of claim 2, wherein due to the overlap, the pattern intensity distribution is more uniform than the mirror intensity distributions (22, 22', 22").

4. The method as claimed in claim 2 or 3, wherein the mirror intensity distribution generates a plurality of pixels (23) which are larger than individual patterns of the exposure pattern (24, 24', 24", 24'").

5. The method of claim 4, wherein the mirror intensity distribution generates a number of pixels (23) based on the geometry of the micromirror (3).

6. The method according to claim 2 or 3, wherein: At least two exposure patterns (24, 24', 24", 24'") are illuminated, and the pattern intensity distributions of the exposure patterns (24, 24', 24", 24'") are superimposed as a sum to form an exposure intensity distribution of the photosensitive layer (9).

7. The method according to claim 6, wherein: At least two exposure patterns (24, 24', 24", 24'") are sequentially illuminated.

8. The method according to claim 2 or 3, wherein the overlapping occurs by an unsharp imaging of the micromirror (3) in the exposure pattern (24, 24', 24", 24'").

9. The method of claim 7, wherein two exposure patterns (24, 24', 24", 24'") sequentially illuminated one after another are shifted to have a relative displacement between the micromirror device (1) and the photosensitive layer (9) smaller than a pixel width.

10. The method of claim 9, wherein: The photosensitive layer (9) is smaller than half the width of a pixel.

11. The method of claim 9, wherein: The photosensitive layer (9) is smaller than a quarter of the width of a pixel.

12. The method according to any one of claims 1 to 3, wherein the exposure pattern grid lines of the exposure pattern (24, 24', 24", 24'") are arranged to extend obliquely and / or to be distorted.

13. The method of claim 12, wherein: The exposure pattern grid lines are affine distorted.

14. The method according to any one of claims 1 to 3, wherein the exposure pattern grid lines of the exposure pattern (24, 24', 24", 24'") are horizontal or vertical.

15. The method of claim 14, wherein: The exposure pattern grid lines extend parallel to each other.

16. An apparatus for exposing a photosensitive layer (9) using an optical system (8), the optical system (8) having: at least one light source (7) for generating at least one light ray (6, 6'), At least one micromirror device (1) having a plurality of micromirrors (3), wherein each micromirror (3) is used to illuminate a pixel (23) of an exposure pattern (24, 24', 24", 24'") having a mirror intensity distribution (22, 22', 22"). It is characterized by The optical system (8) is constructed in such a way that different structures on different focal planes are exposed simultaneously by tilting the focal plane compared to the surface of the layer to be exposed, and a plurality of focal planes are generated using a light source using a plurality of different wavelengths and / or a light source having a broadband wavelength spectrum.

17. The device according to claim 16, wherein To form a pattern intensity distribution of the exposure pattern (24, 24', 24", 24'"), the mirror intensity distribution (22, 22', 22") of the micromirror (3) is superimposed as a sum of the mirror intensity distributions (22, 22', 22") of each illuminated pixel (23) of the exposure pattern (24, 24', 24", 24'").

Images