Exposure control in photolithographic direct exposure methods for manufacturing circuit boards or circuits

Abstract

The invention is directed to a device for exposure control in photolithographic direct exposure processes for two-dimensional structures in photosensitive coatings and to a method for converting registration data into direct exposure data. The object of the invention, to find an improved exposure control in direct exposure methods for two-dimensional structures in photosensitive layers which permits a registration of target marks independent from defined locations of the target marks, is met according to the invention in that a plurality of entocentric cameras are arranged in a registration unit (1) in linear alignment transverse to the one-dimensional movement of the substrate (2) to form a gapless linear scanning area (23) over a predetermined width of the substrate (2). The angles of view (112) of adjacent entocentric cameras have an overlapping region along the linear scanning area (23) in which redundant image captures of the substrate (2) of the adjacent cameras (11) are detectable, and the computing unit (5) has means for calculating the position of the target marks from the redundant image captures of the adjacent entocentric cameras additionally using a height position of the target marks which is determined by triangulation of a distance of the substrate surface (21). (Most illustrative figure: Fig. 1)

Description

[0001] Exposure control in photolithographic direct exposure processes for

[0002] Printed circuit board or circuit manufacturing

[0003] The invention relates to a device for exposure control in photolithographic direct exposure processes for two-dimensional structures in photosensitive coatings, preferably on printed circuit boards, display substrates or wafers, as well as a method for converting registration data into direct exposure data, in particular for adapting the registration to uneven substrates and their implementation as a result of a registration "on the fly".

[0004] “On-the-fly” registration here means that the position data of target marks and thus the position of the substrate to be processed and its unevenness are successively recorded directly during the continuous movement of the substrate and are made available for the alignment of the exposure pattern to the substrate by adjusting the exposure data for the immediately following direct exposure.

[0005] The field of application of the invention lies particularly in the electronics industry and in the semiconductor industry in the production of printed circuit boards, displays and chips.

[0006] Exposure systems for disc- or plate-shaped workpieces are known from the prior art. These systems can expose an exposure object to a predetermined pattern using electromagnetic radiation, predominantly in the visible or ultraviolet spectral range, a laser beam, or an electron beam or particle beam. Exposure only begins after the correct positional relationship has been established between the exposure object and its markings (targets) and a predetermined pattern stored in the exposure device. For this purpose, the targets on the exposure object are captured by one or more cameras, and the exposure object and exposure pattern are aligned with each other before or during the exposure.

[0007] For the production of conductor tracks or extremely small electronic structures on plate-shaped substrates, such as circuit boards, display substrates, or wafers, the exposure processes, which must be carried out with high spatial precision, and the handling and alignment times of the plate-shaped workpieces required for this purpose, are the limiting factors for increasing throughput. Therefore, the aim is to perform the handling and exposure steps overlappingly or simultaneously and, if the front and back sides are to be exposed in the same device, to shorten the downtime of the exposure process. Such solutions are disclosed, for example, in EP 0 951 054 A1, EP 0 722 123 B1, US Pat. No. 6,806,945 B2, and JP 2010-181519 A.

[0008] A further challenge with direct exposure methods is to enable registration independent of the type, number and position of the targets on the exposure object as well as of height deviations of the object surface.

[0009] A solution for capturing surface topographies is known from WO 2016 / 1 15536 ​​A2. In this method, a known two-dimensional pattern, projected onto the surface or otherwise applied, is recorded two-dimensionally together with the surface, and the three-dimensional shape of the surface is determined based on the distortion of the pattern caused by surface irregularities. However, due to its limited resolution, this method is unsuitable for capturing poorly differentiated irregularities.

[0010] EP 0 954 768 B1 describes a device for focusing on the surfaces of a semiconductor wafer. The device records the actual surface topography of a semiconductor wafer prior to exposure in an exposure system. For this purpose, the surface is recorded using a distance sensor to obtain height information, and periodic height fluctuations are then determined and stored. Based on the determined periodic height fluctuations, an optimized focus position for the exposure optics is determined for the partial areas of the wafer surface to be exposed, and the wafer is aligned accordingly. A disadvantage is the time-consuming acquisition of the height information using the distance sensor and the subsequent alignment of the wafer.

[0011] Another registration control for exposing substrates, particularly for laser direct exposure on multilayer PCBs (printed circuit boards), is disclosed in WO 03 / 094582 A2. In this control, a digital control image is generated by non-uniformly modifying a representation of the electrical circuit such that an electrical circuit pattern imprinted on a substrate using the digital control image exactly matches an existing circuit part. For this purpose, selected reference marks are registered on an existing actual structure, with the target structure to be exposed being corrected based on deviations between actual and target positions in the spatial directions, so that exposure occurs with a modified scanning grid. Since a camera integrated into the exposure head is used for registration, each reference mark must be approached by relative movement between the substrate and the scanning head, which is disadvantageous.

[0012] DE 10 2018 132 001 A1 discloses a device for processing plate-shaped workpieces with a high workpiece throughput for use in the direct exposure of printed circuit boards. In this device, the registration unit is equipped with two to three area scan cameras that can be moved laterally to the circuit board movement in order to detect target marks when the position of the target marks on the circuit board is known in advance. The cameras are arranged parallel to a processing path, alternating between two tables moving on the same rail system, in parallel to a processing path, in order to minimize cycle times for processing the printed circuit boards by shortening handling and non-productive times. The cameras are regularly arranged above the edge areas of the printed circuit boards or circuits of a printed circuit board panel in which the target marks are known to be located.The detection of arbitrarily positioned target marks, which are increasingly necessary for printed circuit boards and wafers, is only possible with reduced throughput due to the necessary camera shifts, and height fluctuations of the substrate surface cannot be detected at all.

[0013] EP 2 775 349 A1 describes a method for determining a correct focus position in an optical inspection system. A difference between the focus position of the inspection system and the position of an object to be inspected is determined, whereby an image of the object is captured regardless of the correct focus position. An algorithm of the inspection system can use features of the captured image to determine the magnitude of the difference and direction of the deviation between the focus position and the position of the object by adapting the position of the object to the focus position of the inspection system according to the difference and direction.In the procedure described for a sample to be examined under a microscope, in which various characteristic objects with different spatial dimensions and thus significant height differences within the observed area are to be detected, a singular adjustment of the focus position is required to clearly capture the various objects. Capturing the height profile across the entire area is not planned.

[0014] The patents US 6,245,585 B1 and US 6,449,029 B1 describe methods and devices for adjusting the focus position during photolithography of a semiconductor wafer. Before exposure, the height of the surface in the z-direction is measured in each individual subsection of the wafer to be exposed. The subsections are rectangles arranged in a grid-like manner, which are exposed one after the other. The reflections of five obliquely incident laser beams, one of which is directed at the center and four of which are directed at each of the corners of the subsection, are recorded on the surface of each subsection. From the position of the reflections, offset values ​​by which the height of each subsection deviates from a reference height can be determined, and a surface angle can be calculated for each subsection.Before each section is exposed, the wafer is aligned according to the stored values. Alignment is performed using individually controllable actuators that adjust the height and angle. However, only an averaged correction across the entire section can be set for each section.

[0015] The unpublished DE 10 2019 128 198.9 describes a device for patterning a wound continuous substrate using radiation, in which the target registration and pattern exposure take place on a continuous substrate guided tightly on a processing drum. If the registration unit and processing unit are located diametrically opposite each other on the drum, a change in the height of the substrate due to the drum curvature can be used to adjust both the focusing of the cameras of the registration unit and the processing beam by moving the drum longitudinally to the direction of substrate movement. However, measuring the extent of the defocusing requires additional tools with which the absolute position of the substrate surface can be determined.

[0016] US 2004 / 0223129 A1 discloses an exposure device for the surface exposure of photosensitive material, which is moved in a plane relative to an exposure device comprising a plurality of identical exposure heads arranged in a matrix. In each of the exposure heads, the light from a light source is modulated into a two-dimensional pattern, which is projected onto the material surface for exposure using a telecentric lens. To compensate for unevenness at various locations on the material surface, each exposure head in the beam path has a pair of wedge prisms with which the optical length between the lens and the material surface is adjusted when distance sensors based on reflected laser radiation have detected unevenness due to a changed location on the material surface.The disadvantage here is the individual tracking for each exposure head and its image field as a single image segment, which can lead to sudden changes in the image scale in neighboring image segments.

[0017] The invention is based on the object of finding a new method for improved exposure control in direct exposure processes for two-dimensional structures in photosensitive layers on circuit boards or wafers, which allows for on-the-fly registration of targets independent of defined target locations and avoids the use of expensive telecentric lenses. An extended object is to achieve flexible adaptation of the exposure pattern even for detected substrate unevenness.

[0018] According to the invention, the object is achieved in a device for exposure control during photolithographic direct exposure of two-dimensional structures in photosensitive coatings on a substrate, comprising a registration unit for registering target marks located on a substrate surface, a movable table system for supporting and defined one-dimensional movement of the substrate below the registration unit, a processing unit with a controllable linear processing path for photolithographic processing of the substrate by means of a processing beam for imprinting the two-dimensional structures, and a computer unit for controlling the alignment between the processing path and the substrate by means of local adaptation of the photolithographic processing depending on the position of the substrate determined by registered target marks,that in the registration unit, several entocentric cameras are arranged to form a gapless linear scanning area over a predetermined width of the substrate in a linear alignment transverse to the one-dimensional movement of the substrate and have extended image angles in the direction of the linear scanning area, wherein the image angles of adjacent entocentric cameras along the linear scanning area have an overlap area in order to capture redundant images of the substrate of the adjacent cameras in the overlap area, and that the computer unit has means for calculating the position of the target marks from the redundant images in the overlap area (13) of the adjacent entocentric cameras, additionally using a height position of the target marks determined by triangulation of a distance of the substrate surface.

[0019] Advantageously, the registration unit is equipped with a plurality of entocentric cameras for generating the linearly continuous, gapless sensor area such that image angles of adjacent cameras have an overlap area that is at least as large as half the image angle, wherein the computer unit is set up to determine target marks positioned arbitrarily across the width of the substrate, independently of the position of the target mark, within continuously successive overlap areas of the image angles of adjacent entocentric cameras by triangulation of a distance at any position on the substrate surface.

[0020] The cameras are preferably line scan cameras in order to make the linear scanning area narrow, seamless and with overlapping areas across the entire width of the substrate using cameras with a long scanning length.

[0021] It is advisable to point the cameras at the substrate surface with their optical axes parallel to each other, with the overlapping areas of the image angles of all cameras being the same.

[0022] In another advantageous embodiment, two adjacent cameras with mutually inclined optical axes are directed onto the substrate surface, wherein the overlapping area of ​​the image angles of the mutually inclined cameras is set such that the image angles of the two cameras completely overlap on the substrate surface.

[0023] The overlapping area, which is formed by pairs of cameras inclined towards each other, is connected without gaps to at least one further overlapping area until the overlapping areas have an extent that corresponds at least to the width of the substrate, wherein an overlap can be provided between pairs of cameras inclined towards each other in order to guarantee a gap-free scanning area of ​​the registration unit for all permissible height fluctuations Az of the substrate surface.

[0024] Preferably, the cameras are arranged in pairs with each other tilted so that they are subject to a Scheimpflug condition.

[0025] In an advantageous embodiment of the invention, the computer unit additionally has a control for rapid focus tracking of the processing unit along the processing path as a function of height fluctuations Az of the substrate surface, which includes triangulation of target marks or any imaged structures of the substrate surface on the basis of the redundant image recordings in the overlapping area of ​​the adjacent entocentric cameras.

[0026] In a further preferred variant, the registration unit for target mark detection has only two entocentric cameras arranged on a scanning line (transverse to the direction of movement of the substrate) with an overlap range of one hundredth to one third of the image angle of the camera when the substrate is guided as a flexible endless substrate on a roller table system taut and without height fluctuations Az, wherein the overlap range of the image angles of the two cameras is designed such that the triangulation for the purpose of precisely determining the thickness of the substrate in the overlap range of the image angles on the roller table system can be used and can be assumed to be constant for the entire width of the roller table system.

[0027] Furthermore, the registration unit is expediently equipped with light sources for illuminating the linear, gapless scanning area, which are evenly distributed in the housing to create a scanning line homogeneously illuminated by dark field or bright field illumination.

[0028] The light sources are configured for continuous illumination and have a device for controlling at least one of brightness, angle of incidence, or spectral range. Furthermore, the light sources can be configured for continuous illumination to enable image acquisition by controlling the integration time of the sensor line using an electronic shutter principle.

[0029] In a further preferred embodiment of the invention, a focus tracking system for height fluctuations Az of the substrate is integrated into the processing unit, with which height fluctuations Az determined by the computer unit by means of triangulation from images redundantly recorded with two adjacent cameras of the registration unit can be adapted in real time by rapid focus correction for each pixel of the registration unit, wherein the focus tracking can be controlled on the basis of changes in a lens or mirror position or curvature.

[0030] In this case, the focus tracking is advantageously controllable based on the change in a mirror curvature at least in the transverse direction x to the direction of movement y of the substrate. The focus tracking can preferably be controlled separately based on changes in a mirror curvature in the direction of movement y of the substrate and a mirror curvature in the transverse direction x.

[0031] In a practical design, the focus tracking can be controlled by changing the mirror curvature using a piezo element.

[0032] Advantageously, focus tracking based on changes in a lens or mirror position or curvature can also be used to correct imaging-related focus deviations of an upstream focusing optic or other upstream optical elements resulting from the optics design or optics manufacturing.

[0033] The object is further achieved in a method for exposure control during photolithographic direct exposure of two-dimensional structures in photosensitive coatings on a substrate, comprising the following steps: - arranging a plurality of entocentric cameras to form a gapless linear scanning area transverse to a direction of movement of the substrate in a registration unit for detecting target marks located on the substrate, wherein the entocentric cameras have extended image angles along the linear scanning area with an overlap area formed by adjacent entocentric cameras in order to obtain redundant image recordings of the substrate from adjacent cameras in the overlap area,

[0034] - Moving the substrate on a movable table system in a defined one-dimensional movement below the registration unit,

[0035] - Providing a processing unit for photolithographically producing the two-dimensional structures with a processing beam that can be controlled along a linear processing path,

[0036] - Detecting the spatial position of target marks distributed arbitrarily over a given width of the substrate with regard to length, width and height position during a single pass of the substrate through the linear scanning area of ​​the registration unit,

[0037] - Determining the positions of the target marks distributed arbitrarily across the width of the substrate from the redundant image recordings in the overlapping area of ​​the adjacent entocentric cameras, additionally using a height position of the target marks determined by triangulating a distance of the substrate surface from the redundant image recordings of adjacent entocentric cameras,

[0038] - Calculating data for the alignment and local adjustment of the processing of the substrate with two-dimensional structures for the processing unit to control the processing beam along the linear processing path aligned transversely to the direction of movement of the substrate, and

[0039] - Controlling the alignment between the processing path and the substrate and local adaptation of the photolithographic processing depending on the position of the substrate determined by registered target marks.

[0040] In a preferred method variant, the calculation of the spatial position of target marks distributed arbitrarily across the width of the substrate based on a height position during a pass through the substrate is extended to the triangulation of additional detectable structures of the substrate in the redundant images acquired in the overlap region. Rapid focus adjustment of the focus of the processing beam is performed by means of focus tracking along a processing path based on the control of a lens or mirror position or a mirror curvature. The rapid focus adjustment of the focus of the processing beam is advantageously performed at a frequency at least two to thirty times higher than the conventional scanning frequency for the processing beam.

[0041] The invention is based on the fundamental idea that one or more cameras with two-dimensional sensors (e.g. CCD cameras, CMOS cameras) are used for so-called registration systems. These cameras are usually equipped with telecentric lenses and arranged exactly vertically over defined sections of substrates. As a result, the detected positions remain constant within the available depth of field of telecentric cameras, even if the focus position of the lens relative to the substrate shifts due to changes in thickness or topography. Due to their design, telecentric lenses are comparatively expensive and so bulky that the mechanical dimensions of a lens must always be larger than the image field to be recorded. Telecentric lenses therefore do not allow continuous image recordings by several cameras positioned along a straight line, but would have to be arranged offset along several parallel lines.In addition, an inherent determination of height deviations of the substrate, which is essential for the highly accurate determination of the target position as well as for the precise alignment and adjustment of the exposure pattern, is not possible.

[0042] The invention solves these problems by a combination of a type of linear image scanning across the entire substrate width (hereinafter: FPSS - English: Full Panel Scan System) with a progressive relative movement between the substrate and the linear scanning area by cameras with entocentric lenses whose image angles overlap to such an extent that a triangulation of height differences from several camera images of different cameras is possible for each substrate position of the linear scanning area, or by a defined multi-camera arrangement with cameras positioned obliquely to the substrate, which, while observing a Scheimpflug condition, allows a complete overlap of the image angles of two adjacent cameras and thus a triangulation for each substrate position of the linear scanning area from only two camera images.

[0043] For the purposes of the present invention, definitions from the field of photography are used for the angle of view. The angle of view is understood to be the angle in the object space that is limited by the edges of the recording format of a camera (here, the camera of the recording unit). Accordingly, the angle of view is determined by the height and width of the recording format (as opposed to the diagonal, which is also frequently used and which specifies the maximum angle of view regardless of the actual aspect ratio of the recording format). The recording format is predetermined by the sensor format, whereby an object-side field of view (FOV) is defined via the lens image as the object space spanned by the horizontal and vertical angle of view.

[0044] Apart from the image format—height H and width B of the recording format—the angle of view is essentially determined solely by the current focal length / of the lens. However, the focal length f can only be used directly to define the angle of view when the lens is set to "infinity" (object-side telecentric lens). When imaging objects at a finite distance (short object distance), the image distance b becomes greater than the focal length / and replaces it, resulting in the horizontal angle of view for the width B of the recording format as a= 2-arctan [B !{2 b )] (1 ).

[0045] When using line scan cameras, the horizontal angle of view according to equation (1 ) is the decisive angle of view of the camera due to the almost linear sensor format and can therefore be used alone to define the linear object-side field of view (FOV).

[0046] The height deviations of the substrate along a scanning line determined by local triangulation with entocentric cameras can be used not only for the precise two-dimensional registration of targets but also for the precise tracking of the focus position of the processing beam moving linearly along a processing path. Tracking the processing beam along the processing path for the usual alignment of the exposure pattern to the registered target positions can be supplemented by adjusting mechanisms for quickly changing the focus of the processing beam based on the detected height fluctuations. The focus change must be performed at a frequency at least twice to ten times the usual scanning frequency of the processing beam (between 0.5 and 1 kHz for polygon scanners) and must therefore be controllable by simple linear position changes or changes in the radii of curvature of lenses or mirrors.

[0047] The invention provides a new possibility for improved exposure control in direct exposure processes for two-dimensional structures in photosensitive layers on printed circuit boards or wafers, which allows registration of target marks "on the fly" by means of a linear scanning area independent of fixed location specifications of the target marks for defined exposure fields and avoids the use of expensive telecentric lenses and enables flexible alignment and adaptation of the exposure pattern even for detected unevenness of the substrate.

[0048] The invention is explained in more detail below using exemplary embodiments and illustrations. In the following:

[0049] Fig. 1 : a schematic representation of a registration unit for target detection, designed as a multi-camera configuration, which includes a linear arrangement of entocentric cameras with overlapping image areas to achieve a linear scanning area over the entire object width transverse to the object movement;

[0050] Fig. 2: a schematic representation of the registration unit, designed as a multi-camera configuration in which the linear arrangement of the cameras is formed with pairs of entocentric cameras inclined relative to each other, which satisfy a Scheimpflug condition and in pairs have a completely overlapping image area;

[0051] Fig. 3: a schematic representation for the realization of the alignment of an entocentric camera under Scheimpflug conditions;

[0052] Fig. 4: a schematic perspective view of two selected, consecutive line scans of the registration unit, as well as a result representation of the height variation of the object along two selected line scans; Fig. 5: a schematic view of the triangulation method used for height measurement in the overlap area of ​​two adjacent entocentric cameras;

[0053] Fig. 6: a schematic representation of the invention in a side view transverse to the direction of object movement with an enlarged view of the height fluctuation of the substrate surface, wherein the registration unit is schematically connected to the processing unit via a computer unit for converting the height measurement carried out by triangulation into a precise control of the focusing within the processing beam scanned orthogonally to the drawing plane;

[0054] Fig. 7: a schematic perspective view of the invention with registration unit and processing unit transverse to the substrate movement direction on an endless substrate which is tightly guided on a roller table system;

[0055] Fig. 8: a schematic representation of the realization of the focus control for the current focus tracking by means of a movable objective lens;

[0056] Fig. 9: a schematic representation of the realization of the focus control for the current focus tracking by means of a fixed angle mirror and a movable retroreflector;

[0057] Fig. 10: a perspective view of the realization of an elastically bendable mirror element that changes the mirror curvature with a linear actuator;

[0058] Fig. 1 1 : a schematic representation of the bendable mirror element of Fig. 10;

[0059] Fig. 12: a schematic representation for the realization of the focus tracking with one elastic mirror element according to Fig. 10 for the mirror control separately in the direction of movement and in the transverse direction of the substrate.

[0060] The registration unit 1 according to the invention, in an advantageous basic variant according to Fig. 1, contains a plurality of cameras 11 which form a linear configuration such that their optical axes 111 are directed within the plane of the substrate 2 onto a line (scanning line 23 - only shown in Fig. 2, Fig. 4 and Fig. 6) transverse to the direction of movement of the substrate 2 being moved past, and the substrate width passing through is completely covered by partially overlapping image angles 112 or line-shaped fields of view (FOV) of the cameras 11. This is possible due to entocentric rather than telecentric lenses 15, wherein the cameras 11 are also equipped as line scan cameras with one or a few parallel sensor lines 114.

[0061] The structure comprising cameras 11 with individual sensor lines 114 (so-called line scan cameras, not shown in Fig. 1) is scalable, i.e. any required scanning width can be achieved by combining several cameras 11. Since the exact position of target marks 22 can only be determined in the overlapping area 13 of the image angles 112 of two cameras 11, areas without overlap are lost for an exact measurement, so that the image angles 112 of the cameras 11 in the edge areas of the substrate 2 - provided the overlapping areas 13 are limited to half the image angle 112 - can only be used halfway. For the cameras 11 in the edge area of ​​the substrate 2, only half the image angle 112 is therefore shown in Fig. 1.

[0062] The registration unit 1, with its elongated housing 12, is aligned transversely to the direction of movement of the substrate 2 to be scanned for target marks 22 (only shown in Fig. 2 and Fig. 7), with the substrate 2 being expediently guided underneath on a table system 3 (shown only as a support surface). As can be seen in the side view of Fig. 1, the registration unit 1 has, at a short distance from the substrate surface 21, intensive illumination means which are mounted as light sources 17 in such a way that their illumination light only illuminates the substrate 2 without emitting direct light in the direction of the cameras 11, and the illumination can occur at various oblique angles of incidence (dark-field illumination) and, if necessary, with different spectral colors. Alternatively, it is also possible for the light from the light sources 17 to be coupled directly into the recording beam path of the cameras 11 as bright-field illumination (not shown).

[0063] The camera configuration selected in Fig. 1 consists of five cameras 1 1 with parallel optical axes 1 1 1 and relatively large overlap areas 13 of the cameras 1 1 , which correspond to half the image angle 1 12 of each camera 1 1. This achieves a gapless, approximately linear scan across the full width of the substrate 2, so that with a transversely moved substrate 2, as indicated by the arrow in the right-hand side view of Fig. 1, it is possible to capture all target marks 22 located along the substrate width in one scan without mechanical camera movement. An approximately linear scan by the registration unit 1 is realized by equipping it with cameras 11 in the form of line scan cameras.In order to generate a linear scanning area transverse to the direction of movement of the substrate 2, the entocentric cameras 1 1 with optical axes 1 1 1 lying in a plane (not shown) must be directed onto a scanning line 23 (only shown in Fig. 2) on the substrate surface 21 in such a way that their image angles 1 12 overlap there and form the overlapping areas 13 along the scanning line 23.

[0064] For typical substrate widths of 500-635 mm, entocentric cameras 1 1 (in the form of line scan cameras) with a scanning length of 330 mm in the focus area can be used for the currently required resolution (of 8-12 pm / pixel on the substrate 2), so that a registration unit 1 equipped with five cameras 1 1 can completely span the entire substrate width with a distance of 165 mm between the optical axes 1 1 1 of the cameras 11 in the direction of the substrate width (transverse extent of the substrate 2), whereby each location of the scanning line 23 is recorded simultaneously and redundantly in two different camera images of adjacent cameras 11.For this example, with the five cameras 11 directed onto the scanning line 23, a total scanning length of 660 mm results, which can be moved further together to ensure a gapless double scanning even in the case of positioning or mounting tolerances of the cameras 11 and / or height fluctuations Az of the substrate 2, because the current maximum substrate width (635 mm) is exceeded by 25 mm and thus additional small overlaps 14 of the overlapping areas 13 as well as reliable scanning beyond the edge areas of the substrate 2 are possible.

[0065] With the described arrangement of cameras 11 according to Fig. 1, a truly linear scanning area can be scanned along scan line 23, which has a length-to-width ratio of more than 2,000. In general, registration unit 1 can have a scan line 23 with a length-to-width ratio of several thousand to 100,000, whereby the scanning width in the direction of movement y of substrate 2 can be adjusted by electronic control (synchronization) of the readout modes and speeds of cameras 11 by computer unit 5.

[0066] The cameras 11 arranged according to Fig. 1 with mutually parallel optical axes 1 1 1 are arranged so close to one another along the scanning line 23 (only shown in Fig. 2, 4 and 6) that adjacent cameras 1 1 form an overlap area 13 of at least half the angle of view 1 12 and a further only slight overlap 14 with the angle of view 1 12 of the next but one camera 1 1 is present if, with three or more cameras 1 1, a gapless coverage of the substrate surface 21 with the overlap areas 13 is to be guaranteed even in the case of height fluctuations Az of the substrate 2 and mechanical adjustment inaccuracies.

[0067] At the edges of the substrate 2 or the scanning line 23 formed by the cameras 11, only half the image angle 112 is usable due to the optical axes 111 of the cameras 11 being aligned perpendicularly to the substrate 2, so that an overlap area 13 is always present in the edge region of the substrate 2. This is necessary because, with entocentric cameras 11, the location of a target mark 22 present on the substrate 2 - the further this target mark is spaced from the optical axis 111 - in the camera image is very sensitive to the distance of the substrate surface 21 to the focal plane F n(only designated in Fig. 5) of the respective camera 1 1. To determine the distance of a target mark 22 positioned anywhere on the surface 21 of the substrate 2, a triangulation of two camera images from adjacent cameras 11 along the scan line 23 is therefore carried out and can also be continued for any other point on the scan line 23, provided that - apart from the target marks 22 - evaluable structures are present on the substrate 2.

[0068] In the z-direction, the exact determination of the height fluctuations Az of the substrate surface 21 is limited to areas with detectable points (evaluable structures), so that the height profile of the substrate 2 may have to be supplemented by interpolated values.

[0069] The triangulation of the distance of the substrate surface 21 is crucial for determining the scanning location of a target mark 22, since any height fluctuations Az of the surface 21 of the substrate 2 can lead to significant measurement errors in the determination of the x and y coordinates of a target mark 22, the closer it gets to the edge of the field of view 112 of the camera 11. Light sources 17, positioned at a short distance from the substrate 2 in the housing 12 of the registration unit 1 and arranged at various oblique angles of incidence, are provided for the targeted illumination of the scanning line 23, which is defined by the points of incidence of the optical axes 111 of the cameras 11.

[0070] As already mentioned above, in the camera arrangement according to Fig. 1, each of the outer cameras 11 cannot utilize one half of the image recording area (the image angle 112). An alternative system design based on a Scheimpflug principle, shown in Fig. 2, allows the above disadvantages to be avoided and the scanning areas within the entire image angle 112 of each of the adjacent, mutually inclined cameras 11 to be optimally utilized. However, the demands on the lenses 15 and the alignment and adjustment of the cameras 11 increase.

[0071] While a first gapless registration principle according to Fig. 1 is equipped with five cameras 11 for a total detection width of > 635 mm (> 25"), the same detection width of the registration unit 1 can be scanned by only four cameras 11 in the arrangement principle according to Fig. 2.

[0072] The detection width across all cameras 11 is dimensioned such that it is larger than the maximum processing area of ​​the processing unit 4 (only shown in Fig. 6 and Fig. 7), ie the maximum length of the processing path 41 on the substrate 2, for example generated by a processing beam 45 scanned by means of a polygon scanner (only shown in Fig. 6 and Fig. 7).

[0073] A second constraint for the number and arrangement of the cameras 11 is the required object-side optical resolution, which, depending on the target size to be detected, is often set at approximately 10 pm / pixel and, in the proposed examples, is realized at approximately 11 pm / pixel. A third constraint concerns the scanning speed, which should be adjusted to the desired throughput of printed circuit boards at a substrate speed of 1,000 mm / s to 1,800 mm / s.

[0074] As a compromise between high readout speed, maximizing the scanning width based on a large line length, and a reasonable price for the sensor lines 114, line scan cameras with sensor lines 114 that have more than 3,000 pixels and an edge length of 1 1 pm x 1 1 pm are primarily used for the cameras 11. The required width of the substrate 2 is adapted to the resolution of the line scan camera by means of the image scale of the lenses 15 of the cameras 11.

[0075] In contrast to Fig. 1, Fig. 2 shows a configuration of four cameras 11, which have mutually inclined optical axes 111 in a uniform camera plane along the scanning line 23 in order to be able to register the target marks 22 without gaps for the same scanning range as in Fig. 1 (635 mm). Two cameras 11 form a pair of cameras 11 positioned under Scheimpflug conditions, which have a larger overlap area 13 of their image angles 112, which preferably corresponds to a complete overlap of the image angles 112 of the two cameras 11.

[0076] If the substrate 2 is not wider than this scan line 23 from the image angles 1 12 of the two neighboring cameras 1 1, the triangulation for each substrate point along the scan line 23 can be calculated from the two camera scans of just two neighboring cameras 1 1 that are tilted towards each other. Otherwise, if the substrate width is greater, further cameras 1 1 tilted towards each other in pairs can be lined up along the desired scan line 23 until the overlap areas 13 of the two cameras 1 1 in each case cover the full width of the substrate 2. The overlap areas 13 must at least touch each other, but should not overlap because of possible height fluctuations Az of the substrate 2 and mechanical assembly orAdjustment tolerances of the cameras 11 also have a smaller overlap 14, which for maximum height fluctuations Az and assembly tolerances of the cameras 1 1 always ensures the gap-free scanning of the scan line 23 on the substrate 2 by an additional overlap 14 of the overlap areas 13 formed by the complete overlap of the image angles 1 12 of the respective pairs of cameras 1 1. The advantage of this camera constellation according to Fig. 2 is that in the simplest case exactly two cameras 1 1 "see" the same area of ​​the scan line 23 while observing the Scheimpflug conditions and no partial areas of the image angles 1 12 of the cameras 1 1 remain unused. Compared to Fig. 1, this saves one camera 1 1 for the same length of the scan line 23, ie for the same substrate width.

[0077] At the same time, with each pair of cameras 11 arranged under Scheimpflug conditions, an additional height triangulation for determining the height deviations Az of the substrate surface 21 is possible if a sufficient number of target marks 22 or other scannable structures are present in the overlap area 13.

[0078] Fig. 3 shows one of the two adjacent cameras 11 inclined to each other, in which the image of the object and image plane is rectified by setting different angles of inclination of the lens 15 and the sensor chip 1 13 (or inclination from lens to camera if the latter is viewed separately from the lens 15) and satisfying a Scheimpflug condition.

[0079] In Fig. 4, a sensor line 114 is shown schematically as representative of a camera 11 of the registration unit 1 in order to illustrate the problem of a fluctuating height of the substrate surface 21 using the example of substrate waviness. The upper right partial illustration of Fig. 4 schematically shows a table system 3 moved in the y-direction, on which a substrate 2 is placed. Above the substrate 2 is the registration unit 1, reduced to a sensor line 114, which registers target marks 22 (only shown in Fig. 2 and Fig. 7) along the scanning line 23. For a substrate 2 to be scanned with respect to target marks 22, it is assumed or known that it is either unstable or wavy, which results in height fluctuations Az of the substrate surface 21.With a progressive relative movement of the sensor line 1 14 in the y-direction, different height profiles are recorded along the scanning line 23 (in the x-direction), which, depending on the position of the target marks 22 in the angle of view 1 12 of the entocentric cameras 11, have a reducing effect on the accuracy of the xy position determination of the target marks 22.

[0080] As a result of the advance of the table system 3, the sensor line 114 first scans the dotted scanning line 23', resulting in the dashed profile line in the diagram below. A few readout steps later, the sensor line 114 then detects the solid scanning line 23 and records a solid profile line that deviates significantly from the dashed profile line. These locally very different height fluctuations Az can lead to significant deviations in the exposed structures during processing by the processing unit 4 (only shown in Fig. 6), which are caused by defocusing (broadening) of the processing beam 45. The defocusing can only be corrected by refocusing if the locations of the height fluctuations Az are precisely measured and the focusing of the processing beam 45 is adjusted along a processing line 41 adapted to the positions of the target marks 22 and the height fluctuations Az.

[0081] Fig. 5 shows an example of the determination of the height fluctuations Az of the substrate surface 21 of the substrate 2 by means of triangulation, in which two adjacent cameras 1 1 have parallel optical axes 1 1 1 and two focal planes F lying in the same plane. n and F n+iof the sensor chips 1 13 (shown here for n = 0) and an overlap area 13 of the image angles 1 12 (i.e. the linear scanning ranges) of two cameras 1 1 occurs. This is necessary because the detected target mark positions in the xy plane on the substrate surface 21 when imaged using entocentric lenses 15 are sensitively dependent on the object position in the z direction. Therefore, the target marks 22 to be registered are detected using camera images from a pair of neighboring cameras 1 1 and the target mark positions x, z are calculated using a triangulation method in which the height fluctuation for the z direction is related to two reference planes, which are designated as substrate surface 21 in the lower plane and substrate surface 2T in the upper plane to identify the surface change.The resulting x-position and the resulting height z are ultimately determined from the positions of the different calibration values ​​detected in both cameras 11. with respect to the calibration planes of the substrate surfaces 21 and 21' as follows.

[0082] This means that in addition to the exact determination of the target position in x, the z-position in relation to the calibration planes can be determined. This makes (absolute) height measurement possible.

[0083] Fig. 6 shows a side view of the registration unit 1 analogous to the right-hand sectional view of Fig. 1, and schematically illustrates the linking of the determined position data of target marks 22 (shown only in Fig. 2 and Fig. 7) via a computer unit 5 to the processing unit 4. The problem of an uneven substrate 2 is shown in a stylized and enlarged manner for a wavy substrate surface 21, with the table system 3 assumed to be a precision table.

[0084] When the table system 3 is moved in the y-direction, the registration unit 1 records the x and y positions of target marks 22 arranged anywhere on the substrate 2 in a linear scanning area (scanning line 23, which is formed by several line scan cameras orthogonal to the drawing plane) on the substrate 2 by successive line scans. Due to the overlap areas 13 of the image angles 112 formed by the cameras 11 (only visible in Fig. 1 and Fig. 2), a double scan of each substrate point by two adjacent cameras 11 ensures that not only the exact target mark positions can be determined by means of triangulation, but also the height fluctuations Az of the substrate surface 21 can be calculated.From the measured values ​​of the real substrate height z at each point of the scanning line 23 that can be detected by imaged structures, in addition to the usual alignment of the two-dimensional structure of the processing pattern with respect to the real position of the target marks 22, the processing focus FP (only shown in Figs. 8 and 9) of the processing beam 45 along the processing path 41 is then adjusted in the computer unit 5 to the height fluctuations Az of the substrate surface 21 by means of focus tracking 43.

[0085] In the exemplary embodiment of the invention shown in Fig. 7, the substrate 2 is a continuous substrate that is tautly guided from roll to roll (not shown) via a roller table system 31. The roller table system 31 can have a drum diameter between 200 and 500 mm.

[0086] Due to the tight material guide of the endless substrate 2, the scanning line 23 (not visible in Fig. 7) of the cameras 11 of the registration unit 1 can be arranged in front of the contact line of the substrate 2 with the roller table system 31.

[0087] The registration unit 1 with two entocentric cameras 11 is designed such that the scanning areas of the two cameras 11 form a scanning line 23 (not visible) that extends beyond the edges of the substrate 2 in order to also detect calibration marks 32 on the roller table system 31. For the necessity and handling of the calibration marks 32, reference is made to the unpublished DE 10 2019 128 198.9. Otherwise, the registration unit 1 detects, as described for flat substrates 2 in Figs. 1 and 2, all target marks 22 located on the substrate 2 moved past by the roller table system 31, regardless of where they are located on the substrate 2.

[0088] Due to the special feature that the substrate 2 is guided as an endless substrate tautly on the roller table system 31 and thus does not have any height fluctuations Az caused by waviness of the substrate 2, in this embodiment of the invention a local point-by-point height measurement can be dispensed with and the height measurement of the substrate surface 21 can be limited to a small overlap area 13 of the image angles 1 12 of the two cameras 1 1. In the overlap area 13, which in this case can be much smaller than half the image angle 1 12 of the two cameras 1 1, but at least 1 / 50 (>5 mm) of the detection area of ​​the registration unit 1 (i.e. substrate width plus edge areas of the roller table system 31), preferably between 1 / 40 and 1 / 10, particularly preferably from 1 / 35 to 1 / 25 (approx. 10-15 mm), in analogy to the description of Fig.5 - a triangulation calculation is carried out, from which, in this example, the thickness of the substrate 2 and any thickness fluctuations over the entire length of the continuous substrate can be determined. A rapid change of focus along the processing path 41 by means of the focus tracking 43, as described for Fig. 6, is generally not necessary. Nevertheless, the thickness information, i.e. the z-measurement value as the height of the substrate surface 21, is absolutely necessary for calculating the positions of the target marks 22 in the x and y directions. However, after an initial one-time determination (and, if necessary, repeated individual measurements from time to time), it can be retained for the calculations of the positions of all target marks 22 of the entire continuous substrate.The processing unit 4, which is aligned with the substrate surface 21 in another radial plane of the roller table system 31, sends a scanned processing beam 45 for imprinting two-dimensional structures onto the processing path 41 of the substrate surface 21. However, it can also be arranged in a common plane (e.g., axial plane of the roller table system 31) diametrically opposite to the registration unit 1 on the roller table system 31 (not shown).

[0089] For the height fluctuations Az resulting from the unevenness of the substrate 2 or the substrate surface 21, as described in relation to Figs. 4 and 6, a fast, selective focus tracking 43 for the processing beam 45 along the linear processing path 41 is required according to the invention, so that the latter degenerates into a processing line with variable height.

[0090] Conventional autofocus systems are unsuitable for these rapid focus changes in the z-direction of the processing beam 45 scanned in the x-direction, which is a laser beam for photolithographic direct exposure processes. The basis for the rapid implementation of a local focus change along the processing path 41 according to the invention lies in the detection of the height fluctuations Az of the substrate 2 simultaneously with the registration of the target marks 22 through redundant dual image acquisition using entocentric cameras 11 with seamless overlap areas 13 of their image angles 112 along a linear scanning area (scanning line 23).By means of this height measurement for each pixel of the scanning line 23, which is carried out by triangulation calculations upstream of the processing unit 4 in terms of time and location, the computer unit 5 can, in addition to the already usual adaptation of the data of two-dimensional structural patterns broken down into processing paths 41 to the position of the substrate 2 detected by the detected target marks 22, additionally calculate a point-by-point change in the processing focus FP along the processing path 41 of the processing beam 45 as a function of the data along the scanning line 23 of the registration unit.

[0091] 1 recorded and calculated in the computer unit 5 height fluctuations Az.

[0092] For the rapid focus changes along the processing path 41, additional means are required to supplement the otherwise conventional focusing optics 44. These must be of such quality that they can adjust the scanning frequency of the processing beam 45 in the transverse direction x to the direction of movement y of the substrate.

[0093] 2 by at least twice. Preferably, the frequency of the focus change is between twice and thirty times, particularly preferably between five and twenty times, the scanning frequency of the processing beam 45, which, when using a polygon scanner, is in the range between 0.5 and 1 kHz.

[0094] Fig. 8 shows a first possibility for the realization of the focus tracking 43 by means of a movable lens 431.

[0095] A further embodiment of the focus tracking system 43 according to Fig. 9 provides a fixed corner mirror 432 and a movable retroreflector 433, wherein the corner mirror 432 arranged in the already focused beam decouples the focused beam onto the retroreflector 433 and couples it back in after its reflection, and the retroreflector 433 moves toward or away from the corner mirror 432 in order to shift the focus FP in the z-direction.

[0096] A further mirror-based embodiment of the focus tracking system 43 is described in Figs. 10 to 12. Figs. 10 and 11 show a mirror assembly with a mirror of variable curvature, which is referred to below as an elastically bendable mirror 434. Fig. 11 shows the operating principle as a mechanical equivalent circuit diagram, in which the bendable mirror 434 is movably hinged in the edge region to a mirror mount 436 of a base body and is in contact in the central region with a linear actuator in the form of a piezo stack 435, which is supported on the same base body as the mirror mount 436. Fig. 10 shows the physical implementation of the mirror assembly as a nearly monolithic component, in which the mirror mount 436 as a rectangular cuboid body carries the elastically bendable mirror 434 as a monolithically thinned, pre-curved metal plate, which is elastically mounted on two parallel linear solid bearings.As a result, the bendable mirror 434 is a convex or concave cylindrical mirror that can only change its curvature in one spatial direction.

[0097] According to the embodiment of Fig. 12, for focus control, two crossed elastically bendable mirrors 434 aligned, e.g., in the x and y directions, are arranged in a folded beam path of a multi-element focusing optics 44 for the processing beam 45 (shown only in Fig. 7 and Fig. 8). In this case, the fast focus tracking 43 is integrated into the usual focusing optics 44, wherein the intermediate image plane 441 specifies the point-by-point generation of the two-dimensional structure (not shown) locally adapted to the position of the target marks 22 and predetermined for processing, which is transferred in the image plane 442 to the advantageously used polygon scanner (not shown) for guiding the processing beam 45 along the height-controlled processing line 41 onto the substrate 2.An advantage of this design of the fast focus control with two one-dimensional focus tracking systems 43 is that different focus settings can be used in the x-direction (scanning direction of the processing beam 45) and the y-direction (substrate movement direction). Thus, different focus changes can be accommodated in the scanning and cross-scanning directions of the processing beam 45 (if necessary) with astigmatic or other aspheric optics.

[0098] The invention makes it possible to realize a continuous and approximately one-dimensional scanning line 23 on substrates 2 with height changes or curvatures by using entocentric cameras 11 for target registration, which allows not only detection of the targets 22, but also measurement of the height and height fluctuation Az of the substrate 2. Based on a double scan with two differently positioned cameras 11 along the scanning line 23 of the registration unit 1, triangulation measurements and calculations can be carried out in the overlapping areas 13 using entocentric line cameras whose image angles 112 overlap, which allow a height measurement.By means of point-by-point height measurements, height fluctuations Az of the substrate surface 21 in the processing unit 4, which is also operated with a linear processing path 41, can be taken into account by means of a fast focus control, and when controlling the processing beam 45, they can be corrected by means of a focus tracking 43 or can be turned into a height-adapted processing line at certain points along the processing path 41.

[0099] In addition, the dynamic focus adjustment along the processing path 41 also enables a correction of known imaging-related focus deviations (resulting from the optics design and optics manufacturing) of the processing beam 45 scanned along the processing path 41.

[0100] Reference symbol

[0101] 1 registration unit

[0102] 11 Camera

[0103] 111 optical axis

[0104] 112 angle of view

[0105] 113 Sensor chip

[0106] 114 sensor row

[0107] 12 Housing (of the registration unit)

[0108] 13 Overlap area (the angle of view)

[0109] 14 slight overlap (of angles of view)

[0110] 15 lens (of the camera 11 )

[0111] 151 lens adapters

[0112] 16 Image plane (of the registration unit 1 )

[0113] 161 camera adapters

[0114] 162 surface normals (of sensor chip 113)

[0115] 17 light sources (for illuminating the linear scanning area)

[0116] 2 Substrat

[0117] 21 , 21 ' substrate surface

[0118] 22 Target

[0119] 23, 23' scan line

[0120] 3 table system

[0121] 31 Roller table system (for continuous substrate)

[0122] 32 Calibration mark

[0123] 4 processing unit

[0124] 41 Edit path

[0125] 43 Focus tracking

[0126] 431 movable lens

[0127] 432 (fixed) angle mirror

[0128] 433 (movable) retroreflector

[0129] 434 (elastic) bendable mirror

[0130] 435 piezo stack (linear actuator)

[0131] 436 Mirror mount 437 Solid joint

[0132] 44 Focusing optics

[0133] 441 Intermediate image

[0134] 442 Image plane 5 computer unit

[0135] Fn, Fn+i focal plane

[0136] FP Focus (tracked) x Transverse direction (in the width of the substrate 2) y Movement direction (in the length of the substrate 2) z Focusing direction (in the height of the substrate 2)

[0137] Az height fluctuation (of the substrate surface 21 )

Claims

Patent claims 1. Device for exposure control in photolithographic direct exposure of two-dimensional structures in photosensitive coatings on a substrate, comprising a registration unit for registering target marks located on a substrate surface, a movable table system for supporting and defining one-dimensional movement of the substrate below the registration unit, a processing unit with a controllable linear processing path for photolithographic processing of the substrate by means of a processing beam for imprinting the two-dimensional structures, and a computer unit for controlling the alignment between the processing path and the substrate by locally adjusting the photolithographic processing depending on the position of the substrate determined by registered target marks, characterized in that - in the recording unit (1 ) several entocentric cameras (1 1 ) are arranged in a linear orientation transverse to the one-dimensional movement of the substrate (2) to form a continuous linear scanning area (23) over a predetermined width of the substrate (2) and have extended viewing angles (1 12) in the direction of the linear scanning area (23), wherein the viewing angles (1 12) of adjacent entocentric cameras (1 1 ) along the linear scanning area (23) have an overlap area (13) in order to capture redundant image recordings of the substrate (2) by the adjacent cameras (1 1 ) in the overlap area (13), and - the computing unit (5) has means for calculating the position of the target markers (22) from the redundant image recordings in the overlap area (13) of the adjacent entocentric cameras (1 1 ) by additionally using a height position of the target markers (22) determined by triangulation of a distance of the substrate surface (21 ).

2. Device according to claim 1, characterized in that the recording unit (1) is equipped with a plurality of entocentric cameras (11) for generating the linearly continuous gapless sensor area such that the image angles (112) of adjacent cameras (11) have an overlap area (13) that is at least as large as half the 28 The image angle (1 12) is defined, wherein the computing unit (5) is configured to determine target markers (22) positioned arbitrarily across the width of the substrate (2), independently of the position of the target marker (22) within seamlessly successive overlap regions (13) of the image angles (112) of each adjacent entocentric camera (11) by triangulating a distance at arbitrary positions on the substrate surface (21). The device according to claim 1 or 2 is characterized in that the cameras (1 1 ) are line scan cameras to form the line-shaped scanning area (23) narrow, seamless, and with overlap regions across the entire width of the substrate (2) using cameras (1 1 ) with a large scanning length.A device according to any one of claims 1 to 3, characterized in that the cameras (1 1 ) are directed towards the substrate surface (21 ) with mutually parallel optical axes (1 1 1 ) and the overlap regions (13) of the field of view (1 12) of all cameras (1 1 ) are of equal size. A device according to any one of claims 1 to 4, characterized in that two adjacent cameras (1 1 ) are directed towards the substrate surface (21 ) with mutually inclined optical axes (1 1 1 ) and the overlap region (13) of the field of view (1 12) of the mutually inclined cameras (1 1 ) is adjusted such that the field of view (1 12) of the two cameras (11 ) completely overlap on the substrate surface (21 ).Device according to claim 5, characterized in that the overlap area (13) formed by pairs of cameras (1 1 ) inclined to each other is seamlessly connected to at least one further overlap area (13) until the overlap areas (13) have an extent that corresponds at least to the width of the substrate (2), wherein an overlap (14) may be provided between pairs of cameras (1 1 ) inclined to each other in order to guarantee a gapless scanning area (23) of the recording unit (1 ) for all permissible height variations (Az) of the substrate surface (21 ).

7. Device according to claim 5 or 6, characterized in that the cameras (1 1 ) are arranged in pairs with inclined cameras to each other such that they are subject to a Scheimpflug condition.

8. Device according to one of claims 1 to 7, characterized in that the computer unit (5) additionally includes a control for rapid focus tracking (43) of the processing unit (4) along the processing path (41 ) depending on height variations (Az) of the substrate surface (21 ) which includes a triangulation of target markers (22) or any imaged structures of the substrate surface (21 ) based on the redundant image acquisitions in the overlap area (13) of the adjacent entocentric cameras (1 1 ).

9. Device according to one of claims 1 to 8, characterized in that the registration unit (1 ) for target mark detection has only two entocentric cameras (1 1 ) arranged on a scanning line (23) transverse to the direction of movement of the substrate (2) with an overlap area (13) of one hundredth to one third of the field of view (1 12) of the camera (1 1 ) when the substrate (2) is guided as a flexible continuous substrate on a roller table system (31) taut and without height fluctuations (Az), wherein the overlap area (13) of the field of view (1 12) of the two cameras (1 1 ) is designed such that triangulation for the purpose of accurately determining the thickness of the substrate (2) in the overlap area (13) of the field of view (1 12) on the roller table system (31 ) is applicable and can be assumed to be constant for the entire width of the roller table system (31 ).

10. Device according to one of claims 1 to 9, characterized in that the recording unit (1 ) is equipped with light sources (17) for illuminating the linear gapless scanning area, which are arranged uniformly distributed in the housing (12) to realize a scanning line (23) homogeneously illuminated by dark field or bright field illumination.

11. Device according to claim 10, characterized in that the light sources (17) are designed for continuous illumination and have a device for controlling at least one property of brightness, angle of incidence or spectral range.

12. Device according to claim 10, characterized in that the light sources (17) are set up for continuous illumination in order to enable image acquisition by controlling the integration time of the sensor line (1 14) by means of an electronic shutter principle.

13. Device according to one of claims 1 to 12, characterized in that a focus tracking (43) for height variations (Az) of the substrate (2) is integrated into the processing unit (4), with which height variations (Az) determined by the computer unit (5) by means of triangulation from images redundantly recorded with two adjacent cameras (11) of the recording unit (1) can be adjusted in real time by fast focus correction per pixel of the recording unit (1), wherein the focus tracking (43) can be controlled on the basis of changes in a lens or mirror position or curvature.

14. Device according to claim 13, characterized in that the focus tracking (43) is controllable on the basis of the change of a mirror curvature at least in the transverse direction x to the direction of movement y of the substrate (2).

15. Device according to claim 14, characterized in that the focus tracking (43) is separately controllable on the basis of changes in a mirror curvature in the direction of movement y of the substrate (2) and a mirror curvature in the transverse direction x.

16. Device according to one of claims 13 to 15, characterized in that the focus tracking (43) can be controlled by changing the mirror curvature by means of a piezo element (435).

17. Device according to one of claims 13 to 16, characterized in that Focus tracking (43) based on changes in a lens or mirror position or curvature is also applicable to correcting image-related focus deviations resulting from the optical design or manufacturing of an upstream focusing optic (44) or other upstream optical elements. Method for exposure control in photolithographic direct exposure of two-dimensional structures in photosensitive coatings on a substrate, comprising the following steps: - Arranging several entocentric cameras (11 ) to form a continuous linear scanning area (23) perpendicular to a direction of movement of the substrate (2) in a recording unit (1 ) for detecting target markers located on the substrate (2) (22) wherein the entocentric cameras (11) along the linear scanning range (23) have extended field of view (112) with an overlap area (13) formed by adjacent entocentric cameras (11) in order to obtain redundant image recordings of the substrate (2) from adjacent cameras (11) in the overlap area (13), - Moving the substrate (2) on a movable table system (3) in a defined one-dimensional movement below the recording unit (1 ), - Providing a processing unit (4) for the photolithographic production of the two-dimensional structures with a processing beam (45) that is controllable along a linear processing path (41), - Determining the spatial position of target markers (22) arbitrarily distributed over a given width of the substrate (2) with respect to length, width and height position during a single pass of the substrate (2) through the linear scanning area (23) of the recording unit (1 ), - Determining the positions of the target markers (22) arbitrarily distributed over the width of the substrate (2) from the redundant image acquisitions in the overlap area (13) of the adjacent entocentric cameras (11) using additionally a height position of the target markers (22) determined by triangulation of a distance of the substrate surface (21) from the redundant image acquisitions of adjacent entocentric cameras (11), - Calculating data for the alignment and local adjustment of the processing of the substrate (2) using two-dimensional structures for the processing unit 32 (4) for controlling the processing beam (45) along the linear processing path (41) oriented transversely to the direction of movement of the substrate (2), and - Controlling the alignment between the processing path (41) and the substrate (2) and locally adjusting the photolithographic processing depending on the position of the substrate (2) determined by registered target marks (22).

9. Method according to claim 18, wherein the calculation of the spatial position of target marks (22) arbitrarily distributed over the width of the substrate (2) based on a height position during a pass of the substrate (2) is extended to the triangulation of further detectable structures of the substrate (2) in the redundant images acquired in the overlap area (13), and a rapid focus adjustment of the focus (FP) of the processing beam (45) is carried out by means of a focus tracking (43) along a processing path (41) based on the control of a lens or mirror position or a mirror curvature. 0.Method according to claim 19, wherein the rapid focus adjustment of the focus (FP) of the processing beam (45) is performed at a frequency at least two to thirty times higher than the conventional scan frequency for the processing beam (45). - This includes 9 pages of drawings - 33