Method and system for generating line width optimized pattern

Abstract

A method for obtaining line width compensation data for a workpiece patterning apparatus comprises printing (S2) a calibration pattern with an exposure beam sweeppable in a sweeping direction. The calibration pattern has a plurality of exposed and unexposed lines extending in the sweeping direction, the plurality of exposed and unexposed lines having different line widths and different distances to adjacent lines. And measuring the line width (S4). A deviation in the measured line width is calculated (S6). Based on the calculated deviation, line width compensation data is calculated (S8) for adapting a line width of the pattern print data prior to printing to compensate for the calculated deviation. The line width compensation data is associated with at least an expected line width and information about whether the line is an exposed line or an unexposed line. Methods for calibrating print data and methods for printing patterns based thereon, and systems for calibrating print data are also disclosed.

Description

Technical Field

[0001] The present technology relates to pattern printing and an apparatus thereof, and in particular to a method for obtaining a compensation pattern for a workpiece pattern forming apparatus, a method for calibrating printing data, a method for printing a pattern and an apparatus thereof. Background Art

[0002] In today's semiconductor industry, masks produced by laser-based mask writers are commonly used to manufacture different kinds of advanced chips and imaging devices. Direct writers for electronic packaging, for example, are also standard today. The production of larger and more precise displays has also increased significantly in the past few years. Therefore, it is required that processes such as microlithography be faster, more precise, and cheaper.

[0003] In the field of microlithography, mask writers or direct writers can be based on a print head that provides one or more precise laser beams. The print head and the substrate to which writing is to be performed can be moved relative to each other by moving the print head or the substrate or both. By varying the power of the laser beam coordinated with the relative movement, the exposure pattern can be written onto the substrate.

[0004] The precision of printing is crucial. Deviations from the intended pattern, such as critical dimension (CD), critical dimension linearity (CDL) or positioning errors, even in the range of a few nanometers to hundreds of nanometers can be detrimental to or degrade the final result. Such printing errors are usually caused by defects in the mechanical and / or optical properties of the print head.

[0005] In the published US patent US 7,919,218 B2, a method for a multi-exposure beam lithography tool is disclosed. The invention describes a method for patterning a workpiece covered with a layer sensitive to electromagnetic radiation by using multiple exposure beams simultaneously. It is determined whether any beam has an actual position different from its expected position relative to a reference beam. If the beam is printed at the edge of a feature, an exposure dose adjustment is performed for the incorrectly positioned beam.

[0006] Such corrections are designed to correct beam position errors, but deviations from the expected pattern may also depend on many other causes which cannot be compensated by such exposure adjustments.

[0007] In the published international patent application WO 2021 / 254726 A1, a method for obtaining a compensation pattern for a workpiece pattern forming device is disclosed. According to calibration pattern printing data having multiple edges, a calibration pattern is printed using multiple simultaneously operating exposure beams that are sweepable in a second direction. The position of the edge is measured. The deviation of the measured position relative to the calibration pattern is calculated. Each deviation is associated with the exposure beam used, the sweep position, and the grid fraction position. Edge compensation data is calculated for adapting the edge representation of the pattern printing data before printing to compensate for the calculated deviation. The edge compensation data depends on the exposure beam used, the sweep position, and the grid fraction position.

[0008] Such corrections are designed to correct CD errors, but CDL deviations may still exist. Summary of the invention

[0009] The general purpose of this technique is to improve critical dimension linearity.

[0010] The above objects are achieved by a method and an apparatus according to the independent claims.

[0011] Preferred embodiments are defined in the dependent claims.

[0012] Generally speaking, in a first aspect, a method for obtaining line width compensation data for a workpiece pattern forming device includes printing a calibration pattern with an exposure beam that can be scanned in a sweep direction. Printing is performed according to the calibration pattern printing data. The calibration pattern has a plurality of exposed lines and unexposed lines extending in the sweep direction, and the plurality of exposed lines and unexposed lines have different line widths and different distances to adjacent lines. The line width of the line is measured in a scanning direction perpendicular to the sweep direction in the printed calibration pattern. The deviation of the measured line width of the line relative to the expected line width of the line is calculated according to the calibration pattern printing data. The line width compensation data is calculated based on the calculated deviation. The line width compensation data is intended to be used to adapt the line width of the pattern printing data before printing to compensate for the calculated deviation. The line width compensation data is associated with at least the expected line width and information about whether the line is an exposed line or an unexposed line.

[0013] In a second aspect, a method for obtaining line width compensated printing data comprises obtaining printing data of a pattern to be printed. Identifying lines in a scanning direction in the pattern to be printed. Determining line attributes of the lines. The line attributes include at least line width and information about whether the line is an unexposed line or an exposed line. Deriving a line width adjustment value for each identified line from the line width compensation data. Based on the determined line width and the information about whether the line is an unexposed line or an exposed line, obtaining line width compensation data by the method according to the first aspect. Adapting the printing data defining the identified lines to line width compensated printing data according to the line width adjustment value.

[0014] In a third aspect, a method for printing a pattern comprises obtaining line width compensated printing data. The line width compensated printing data is obtained by the method according to the second aspect and is related to the pattern to be printed. A printing process of a workpiece at least partially covered with a layer sensitive to electromagnetic radiation or electronic radiation is controlled based on the line width corrected printing data.

[0015] In a fourth aspect, a system for obtaining line width compensation data for a workpiece pattern forming device includes a printing device, a measuring device, and a processing device. The printing device is configured to create a calibration pattern with an exposure beam that can be scanned in a sweep direction. The printing device is configured to perform printing according to the calibration pattern printing data. The calibration pattern has a plurality of exposed lines and unexposed lines extending in the sweep direction, and the plurality of exposed lines and unexposed lines have different line widths and different distances to adjacent lines. The measuring device is arranged to measure the line width of the line in a scanning direction perpendicular to the sweep direction in the printed calibration pattern. The processing device is configured to calculate the deviation of the measured line width of the line relative to the expected line width of the line according to the calibration pattern printing data. The processing device is also configured to calculate line width compensation data based on the calculated deviation, and the line width compensation data is used to adapt the line width of the pattern printing data before printing to compensate for the calculated deviation. The line width compensation data is associated with at least the expected line width and information about whether the line is an exposed line or an unexposed line.

[0016] In a fifth aspect, a device for processing printing data defining a pattern to be printed comprises a processing circuit and a memory. The memory comprises instructions executable by the processing circuit. Thus, the processing circuit is operable to obtain printing data for the pattern to be printed. The processing circuit is also operable to identify lines in a scanning direction in the pattern to be printed. The processing circuit is also operable to determine line attributes of the lines. The line attributes include at least line width and information about whether the line is an unexposed line or an exposed line. The processing circuit is also operable to derive a line width adjustment value for each identified line from the line width compensation data obtained by the method according to the first aspect based on the determined line width and the information about whether the line is an unexposed line or an exposed line. The processing circuit is also operable to adapt the printing data defining the identified line to line width compensated printing data according to the line width adjustment value.

[0017] In a sixth aspect, a printing device comprises a device for processing line width compensated printing data, a printing head and a control unit. The line width compensated printing data is obtained by the device for processing printing data according to the fifth aspect. The printing device is a printing device of the system for obtaining a compensation pattern for a workpiece pattern forming device according to the fourth aspect. The printing head has an exposure beam that can be scanned in a sweeping direction. The control unit is arranged to control the operation and relative movement of the printing head based on the line width compensated printing data.

[0018] One advantage of the proposed technique is that the compensation in the data becomes very repeatable and can be calibrated by linear measurements. It can therefore be adjusted for all conditions and system types. Recalibration can be performed by new measurements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention and further objects and advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 A printing device is schematically shown;

[0021] Figure 2 Printing with a micro-scanned exposure beam is shown;

[0022] Figure 3 is a graph showing a linear measurement of critical dimensions;

[0023] Figure 4 A printing apparatus having a plurality of exposure beams is schematically shown;

[0024] Figure 5 Printing with multiple exposure beams and micro-scanning is shown;

[0025] Figure 6 is a flow chart of steps of an embodiment of a method for obtaining a compensation pattern for a workpiece patterning device;

[0026] FIG. 7A to FIG. 7B The exposed lines and the unexposed lines are schematically shown respectively;

[0027] Figure 8 is a graph showing the relationship between the expected line width and the compensated line width;

[0028] Fig. 9 is a flow chart of steps of an embodiment of a method for calibrating print data;

[0029] Fig.10 shows the adjustment of intensity in the bitmap domain;

[0030] Fig.11 is a diagram showing the relationship between expected line width and line width compensation;

[0031] Fig.12 is a flow chart of steps of an embodiment of a method for printing a pattern;

[0032] FIG. 13A to FIG. 13B Densely exposed lines and densely unexposed lines are schematically shown, respectively;

[0033] Fig.14 is a schematic diagram of an embodiment of a system for obtaining a compensation pattern for a workpiece patterning device;

[0034] FIG. 15A to FIG. 15B is a schematic diagram of an embodiment of an apparatus for processing printing data defining a pattern to be printed; and

[0035] Fig.16 is a schematic diagram of an embodiment of a printing apparatus. DETAILED DESCRIPTION

[0036] Throughout the drawings, the same reference numerals are used for similar or corresponding elements.

[0037] To better understand the proposed technique, it may be useful to start with a brief overview of printing systems with micro-scanning capabilities.

[0038] Figure 1 Schematically shown is a printing device 1 comprising a table 10 on which a workpiece support 12 is arranged. The workpiece support 12 is movable relative to the table 10 in a direction Y. On the workpiece support 12, a workpiece 20 is firmly attached. The surface of the workpiece 20 is provided with a layer sensitive to electromagnetic radiation or particle radiation.

[0039] The printing device 1 further comprises a workpiece patterning device 2. The workpiece patterning device 2 comprises a support 30 supporting a print head 32. The print head 32 is movable along the support 30 in a direction X. The print head 32 is arranged for providing an exposure beam 34 for exposure with electromagnetic radiation or particle radiation, the exposure beam 34 being directed towards the workpiece 20.

[0040] As will be described further below, the combined movement of the workpiece support 12 and the movement of the print head 32 makes it possible to reach all areas on the workpiece 20 that should be exposed to radiation by microsweeping of the exposure beam 34. In the figure, exposed areas 24 and unexposed areas 22 are shown.

[0041] As will be appreciated by those skilled in the art, in other embodiments, relative mechanical movement may be achieved in other ways, for example, the print head 32 may be movable in two dimensions and / or the workpiece support 12 may be movable in two dimensions.

[0042] In printing devices of this type, use is made of a micro-scanning of the exposure beam. Figure 2This is shown in a schematic manner. By allowing the beam to sweep over a small distance in a direction perpendicular to the main direction of motion of the print head, the width of the printed strip is increased, which also increases the overall printing speed. A portion of a workpiece 20 is shown. At the moment shown, the exposed area 24 is shown by hatching, while the unexposed area 22 is not shown. Here, it will be understood that the actual degree of exposure also depends on the intensity of the exposure beam at each position. However, in this figure, the "exposed area" 24 is the area that the exposure beam 34 has passed through or should have passed through if intensity was applied in this case.

[0043] Thus, it can be understood that the accuracy properties of the pattern in the X and Y directions, respectively, are partially controlled by different device properties. The accuracy in the Y direction is highly dependent on, for example, the accuracy of the intensity variation control during micro-scanning or the uniformity of the micro-scanning speed. In contrast, the accuracy in the X direction depends on the accuracy of the print head movement and the repeatability of the micro-scanning conditions.

[0044] One of the most important characteristics of a pattern printing system is the CD linearity in X and Y. CD linearity is defined as the measured line width deviation as a function of the pattern line width. A characteristic of today's typical mask printer or direct printer systems is that the X linearity falls off before the Y linearity. This sets the actual useful resolution of the writer system used for production.

[0045] Figure 3 is a graph showing CD linearity in the X and Y directions of a prior art pattern printer. The square connected to curve 101 represents CD in the Y direction, and the star connected to curve 102 represents CD in the X direction. It can be seen here that when the line width becomes less than about 500nm, the X curve 102 drops significantly, while the Y curve 101 is more or less unaffected. However, due to the varying behavior in the X direction, the stable characteristics in the Y direction are useless.

[0046] Furthermore, it has been found that the CD linear profile also depends on whether the line is an exposed line or an "unexposed line", ie a line that has not been exposed.

[0047] It has also been found that the curve can change depending on how densely the lines are provided. Thus, an isolated line can have a different CD linear profile than lines in a neighborhood of other lines.

[0048] One contributing cause of these nonlinearities is believed to be related to the intensity distribution of the exposure beam. In order for a spot at the substrate to appear exposed, the light intensity must exceed a certain threshold. However, the edges of the exposure beam are not sharp, but the spatial distribution of the light varies continuously over the beam. It is expected that the spots at the substrate that are exposed for intensities below the threshold will be etched away in the next production step. However, if a high degree of adjacent spots are illuminated, the total "stray" intensity may exceed the threshold and the spot will appear to be exposed. Therefore, at very narrow structures, the exposure pattern of adjacent spots may give unpredictable variations in the area where "exposure" is believed to have occurred. This will produce a CD linear profile that will vary with line width as well as line characteristics (i.e., exposed or unexposed lines).

[0049] In many pattern printers, multiple beams are used simultaneously. By using a print head with multiple beams for simultaneous exposure, the overall speed can be increased. Figure 4 A printing device 1 is schematically shown, wherein a print head 32 is arranged for providing a plurality of exposure beams 34. As indicated by the double arrows, the exposure beams 34 are typically micro-scanned in synchronism with each other.

[0050] Figure 5 This is shown in a schematic manner. A portion of a workpiece 20 is shown. At the moment shown, the exposed areas 24 are shown by hatching, while the unexposed areas 22 are not shown.

[0051] In this figure, five exposure beams 34A-E are shown. As will be appreciated by those skilled in the art, the number of exposure beams may be selected based on, for example, the required printing speed, available exposure beam size, overall complexity, etc. However, in this exemplary illustration, five exposure beams 34A-E have been selected simply to make the illustration of the printing principle easier to identify.

[0052] In this illustration, the print head (not shown) can be moved in steps downward in the X direction in the illustration. The print head moves at regular distances, as shown by the exposure beam step 50. At each position, the exposure beam is swept upward in the Y direction in the figure in a so-called micro-sweep to cover the sweep width 52. In the illustrated example, the micro-sweep is performed almost halfway through the micro-sweep. After completing the micro-sweep, the print head moves another exposure beam step 50 in the X direction and performs a new micro-sweep. As can be seen from the figure, when all exposure beams have passed a certain X position, the entire surface of the workpiece is exposed (or may have been exposed). Therefore, different exposure beams are planned to fill the space between each other to establish exposure of the entire surface. The exposure beam width 56 corresponds to the width of the micro-strip exposed during the micro-sweep, and in order to cover the entire surface, the exposure beam width 56 multiplied by the number of exposure beams is equal to the exposure beam step 50. However, it can be seen that the exposure beam interval 54 is different from the exposure beam step 50.

[0053] In other embodiments, the print head is moved continuously. Then, when the print head enters the correct position for micro-sweeping initiation, the micro-sweep is activated. The continuous movement causes the relative position between the stage and the print head to change during the micro-sweep. This can usually be compensated in different ways, for example, by performing the micro-sweep at a small angle (usually expressed as an azimuth) relative to the normal to the direction of movement to produce a final vertical sweep relative to the stage. Such an arrangement, for example, implemented by an angled sweep optic, is itself well known in the prior art.

[0054] The movement of the print head is planned so that the different exposure beams cover the entire surface of the workpiece 20 .

[0055] It has been found that the CD linearity characteristics identified above are substantially independent of whether a single exposure beam is used or whether multiple exposure beams are used to print the line.

[0056] CD linearity is expected to be affected by many different measures. This can include, for example, improving the laser spot, laser and optical alignment, minimizing stray light, using the best available resists and lithography processes. However, since most of these factors have improved over the years, further improvements would require extreme measures regarding, for example, alignment, which are expensive and typically require frequent recalibration processes.

[0057] Therefore, in the present disclosure, it is presented that as an alternative or further improvement to such CD linearity improvement measures, modification of the pattern data in the pixel domain can be used to improve the linearity in the X direction. Thus, narrower lines can be resolved linearly within specification. This is of high value to the user.

[0058] Figure 6 1 is a flow chart of steps of an embodiment of a method for obtaining a compensation pattern for a workpiece pattern forming device. In step S2, a calibration pattern is printed with an exposure beam that can be scanned in a scanning direction. Printing is performed according to calibration pattern printing data. The calibration pattern has a plurality of exposed lines and unexposed lines extending in the scanning direction and having different line widths and different distances to adjacent lines. The line width is preferably in the range of the minimum possible line width obtainable from the printer to a line width sufficient for the edges to be considered independent of each other. For example, in the method for obtaining Figure 3 For a system with a curve, compensation for linewidths between 200 nm and 600 nm may be of interest, and the linewidths of the calibration pattern should in this case at least cover this range.

[0059] In step S4, the line width of the line is measured in a scanning direction perpendicular to the scanning direction in the printed calibration pattern. In step S6, the deviation of the measured line width of the line of the calibration pattern printing data relative to the expected line width of the edge is calculated. In step S8, based on the calculated deviation, line width compensation data is calculated. The line width compensation data is intended to be used to adapt the line width of the pattern printing data before printing to compensate for the calculated deviation. The line width compensation data is associated with at least the expected line width and whether the line is an exposed line or an unexposed line.

[0060] FIG. 7A to FIG. 7B Different options are shown. Fig. 7A An exposed line 110 is shown. The exposed line 110 is surrounded by an unexposed area 112 in the X direction and is associated with a certain width 114. Figure 7B Similarly shown is an unexposed line 116. The unexposed line 116 is surrounded by an exposed area 118 in the X direction and is also associated with a specific width 114.

[0061] There are different types of photoresists. If a photoresist is used that will remain after etching if illuminated, the exposed areas will result in a "dark field". The unexposed areas will then result in a "clear field". If not explicitly stated differently, this is the type of photoresist used as an exemplary choice in the present disclosure. However, if a photoresist is used that will be etched away when illuminated, the exposed areas will result in a "clear field". The unexposed areas will then result in a "dark field" instead. The idea of ​​the present invention applies to both alternatives.

[0062] For each measured line width, at least two different CD linearity curves are obtained, one for the exposed lines and one for the unexposed lines.

[0063] If a line with a certain expected line width turns out to always be printed with another line width, this non-linearity can be compensated. If the printed line width is measured to be less than the expected line width, the original print data can be pre-compensated by requesting a slightly wider line width. Similarly, if the printed line width is measured to be greater than the expected line width, the original print data can be pre-compensated by requesting a slightly narrower line width. In this case, the final printed line can exhibit the originally expected line width. Compensation data can be determined. Figure 8 A non-linear compensation curve 120 for the exposed lines is shown. Compared to the measured CD linearity, the curve behaves in an inverse manner. The expected line width 122 is related to the compensated line width 124 by the curve. Thus, the curve 120 is an example of line width compensation data. The line width compensation data may also be provided in other ways, for example as a look-up table, where the expected line width is used as an entry value.

[0064] Fig. 9Flowchart of the steps of an embodiment of a method for calibrating print data. In step S10, print data of a pattern to be printed is obtained. In step S12, lines in the scanning direction in the pattern to be printed are identified. In step S14, line attributes of the lines are determined. The line attributes include at least line width and whether the line is an unexposed line or an exposed line. In step S16, a line width adjustment value is derived for each identified line from the line width compensation data obtained by the method described above. The inference is based on the determined line width and based on whether the line is an unexposed line or an exposed line. In step S18, the print data defining the identified line is adapted according to the line width adjustment value. This adaptation results in line width compensated print data. When printing a pattern, the print data is usually provided in a vector domain. This is usually converted into a bitmap domain, in which a pixel raster associated with each intensity is defined. When performing exposure, the exposure beam is moved according to the pixel, and the exposure intensity at each pixel is controlled to correspond to the associated intensity value.

[0065] The adaptation of the print data may be performed in the bitmap domain. Fig.10 A portion of bitmap printing data is schematically shown, wherein different pixels 90 are defined by dotted lines. The original bitmap printing data is shown in the left portion of the figure. An unexposed line 116 with an expected line width 114 is surrounded by an exposure area 118. The expected edge 84 of the unexposed line 116 is not completely consistent with the pixel boundary, and in order to achieve an exposure slightly offset from the pixel boundary, the associated intensity in the pixels around the unexposed line edge 84 is adjusted to cause the displacement of the position where the exposure reaches the level at which the position is considered to be exposed. The third pixel column from the right is given a low intensity because the expected edge 84 is just within the right pixel boundary. In order to shift the pattern edge from the pixel boundary by a distance less than the width of the pixel, this use of intensity variation itself is well known to those skilled in the art and will not be further discussed or explained.

[0066] According to the line width adjustment concept further presented above, an adjusted line width may be useful. In the embodiment shown, such an adjusted line width is defined by an adjusted line edge 85. It is thus required that the edges of the line are adjusted by the amounts Δ1 and Δ2, respectively. The sum of Δ1 and Δ2 corresponds to the amount of the derived line width adjustment value. In other words, the intensity of the individual bits at or immediately adjacent to each edge of the line to be adjusted is adjusted to achieve a sum of corresponding line edge position adjustments equal to the amount of the derived line width adjustment value.

[0067] exist Fig.10 The right part of shows the adjusted line width compensated print data. Here, the associated intensity is adapted to correspond to the adjusted line edge 85, which gives an adjusted line width 86.

[0068] The edge adjustments add up to the total derived line width adjustment value. Preferably, half of the derived line width adjustment value is adjusted at each edge. However, in other embodiments, another partitioning may be applied. The partitioning may also depend on, for example, an imbalance of exposure density in the corresponding edge neighborhood.

[0069] When measuring the nonlinearity of the line width, a plurality of discrete values ​​of the line width are used. From the measurement of these discrete values ​​of the line width, line width compensation data are derived. This can for example be assigned line width compensation values ​​for a set of discrete line width values ​​or a continuous line width compensation curve. If for example a lookup table is to be used, a set of discrete line width compensation values ​​may be advantageous.

[0070] Fig.11 A diagram is shown for determining a set of discrete line width compensation values ​​121. These values ​​are valid for exposed lines or unexposed lines and, as will be further described below, may also be valid for a certain proximity indicator. For an expected line width that corresponds exactly to these discrete line width compensation values ​​121, the choice is obvious. If the expected line width falls between the discrete values, a different approach can be used. One alternative is to determine the closest line width for which there is a determined discrete line width compensation value 121 and use that value. This is shown by the short dashed line 126.

[0071] Another alternative is to use interpolation. Thus, in one embodiment, the derivation of the line width adjustment value includes interpolation using the line width adjustment value from the line width compensation data corresponding to the closest larger line width and the closest smaller line width. This is shown by the dashed line 123. The interpolation can be linear or according to any other interpolation technique familiar to those skilled in the art.

[0072] When line width compensated printing data is available, the printing process can begin. Fig.12 is a flow chart of steps of an embodiment of a method for printing a pattern. In step S20, line width compensated printing data of a pattern to be printed are obtained. The line width compensated printing data are obtained according to the method described in the present disclosure. In step S22, a printing process of a workpiece at least partially covered with a layer sensitive to electromagnetic radiation or electronic radiation is controlled based on the line width corrected printing data.

[0073] As mentioned above, the use of multiple exposure beams is common. Therefore, in one embodiment, the step of controlling the S22 printing process includes controlling the exposure beams operating simultaneously to provide micro-scanning in the scanning direction while being scanned in a scanning direction perpendicular to the scanning direction. Thereby creating a scanning strip.

[0074] In another embodiment, the step of controlling S22 the printing process further comprises creating a plurality of such scanning strips shifted in the second direction.

[0075] The printing process may be a microlithography process. In different embodiments, the printing process may be a mask writing process or a direct writing process.

[0076] One factor that leads to line width non-linearity is the influence of radiation exposure intended for adjacent or at least closely located pixels. This "unintended" radiation contributes to the background radiation level, affecting the position of the edges of the printed lines. This is an important reason why the line compensation is different for exposed lines compared to unexposed lines. However, the general background radiation level can also be advantageously taken into account. In a preferred embodiment, the additional use of a proximity factor is applied.

[0077] exist Fig. 7A In FIG. 1 , an exposure line 110 is shown. Since the exposure line 110 is surrounded by a large unexposed area 112, the exposure line 110 can be considered as an isolated exposure line 110. Fig.13A In FIG. 1 , an exposure line 110B is shown, which has a line width 114, but in which the surrounding unexposed area 112 is limited. Therefore, other exposure areas 111 exist within a distance 119 not too far from the exposure line 110B. Such an exposure line 110B can be considered a dense exposure line. The background radiation level from the adjacent exposure areas 111 can affect the actual printed line width of the exposure line 110B.

[0078] Fig. 13B Similarly, dense unexposed line 116B is shown, having line width 114, with other unexposed areas 117 within a relatively close distance 119. In contrast, Figure 7B Isolated unexposed lines 116 are shown.

[0079] In one embodiment, the proximity indicator is used to determine the adjustment of the line width. Figure 6 As shown, the method for obtaining a compensation pattern for a workpiece pattern forming device may include an additional step S7. In step S7, a proximity indicator is determined for each line in the calibration pattern. The proximity indicator is a parameter that represents the relationship between the exposed area or the unexposed area in the surroundings of the line in the calibration pattern. The line width compensation data is thus further associated with the proximity indicator.

[0080] In the method for calibrating print data, the proximity indicator can be used to further refine the line width adjustment. Therefore, in one embodiment, the line attributes also include a proximity indicator. The proximity indicator is a parameter representing the average fraction of exposed or unexposed areas in the surroundings of the line. The line width compensation data is further associated with the proximity indicator.

[0081] In one embodiment, the proximity indicator is a line density classification with at least two categories. These categories can be, for example, dense lines and isolated lines. Separate line width compensation is then implemented for dense exposed lines, isolated exposed lines, dense unexposed lines, and isolated unexposed lines.

[0082] In one embodiment, the proximity indicator is a line density metric. Such a line density metric may be the ratio between the distance 119 to the nearest neighbor and the line width 114. The ratio may be evaluated on both sides or one side and then applied separately on each side or as an average on both sides.

[0083] In some embodiments, such a line density metric may then be divided into two or more ranges for classification purposes when deriving line width adjustment values. In other embodiments, derivation of line width adjustment values ​​may include interpolating using width adjustment values ​​from line width compensation data corresponding to the closest larger line density measurement and the closest smaller line density measurement.

[0084] In one embodiment, a range of "completely isolated lines" may be considered to exist if the ratio is greater than or equal to 5. A range >2 but <5 may be represented as "slightly dense", a range >1 but ≤2 may be represented as "moderately dense", and a range ≤1 may be represented as "very dense".

[0085] This proximity indicator, being the ratio of distance to line width, is an approximation. It assumes that line width contributions always come only from the nearest neighbor on each side. However, this is a useful and typical approximation. The most typical case is when over some region the line width and distance to neighbors remain constant in the evaluation direction for a considerable number of repetitions.

[0086] It can be said that the proximity indicator as described above corresponds to a parameter representing the average fraction of exposed or unexposed areas in the surrounding environment. The density ratio is a common way to represent this, however, it should also be understood that only the average is considered vertically.

[0087] The proximity indicator defined in the manner described above works well with the typical way of measuring and evaluating CD linearity. Two two-dimensional lookup tables are added. For each line measured, the line width in the data representation and the distance to the nearest neighbor in the data representation give a closeness ratio, typically as a decimal value.

[0088] In one embodiment, the exposed lines select a first lookup table, while the unexposed lines select another lookup table. For a discrete number of line widths, there are a discrete number of correction values ​​for the measured density ratio. In both dimensions, linear interpolation is applied, i.e., bipolar linear interpolation. In other words, linear interpolation is performed between the closest line widths, and also between the closest density ratio values.

[0089] As mentioned above, the density ratio can be evaluated one-sidedly or two-sidedly. The compensation can also be the same on both sides, ie applied half on each side, or applied on each side as a value calculated to best compensate for the influence of adjacent light on that side.

[0090] In one embodiment of the above disclosed concept, a new table-based line width compensation is employed for the narrowest line width in the X direction. The implementation is based on one-dimensional edge detection in pattern data without optical proximity effects, with a sliding window of pixel data, suggested to be about 7 to 10 data micro-sweeps.

[0091] This can be done before or after other types of compensation (such as CD compensation or corner enhancement). In addition, similar basic techniques are used. Although the necessary changes are unique, they are easily implemented requiring only easy-to-perform adaptations, which limits the implementation costs.

[0092] By using a sliding window of size 7, narrow lines up to five pixels can be compensated, which is the sliding window size minus two. Each edge can be compensated plus or minus one pixel. For a system with a pixel size of 170nm, this means that lines narrower than 850nm in X can be compensated, down to a single pixel line, which is typically well below the actual resolution. An example of a sliding window routine is shown in Appendix A.

[0093] As described above, for photoresists that are etchable when illuminated, compensation can be performed on both clear field lines (exposed on an unexposed background) or dark field lines (unexposed lines on an exposed background). This compensation table can be created using a combination of linear model data based on simulations and linear measurements.

[0094] Fig.14 An embodiment of a system 70 for obtaining a compensation pattern for a workpiece patterning device is schematically shown. The system 70 for obtaining a compensation pattern for a workpiece patterning device comprises a printing device 1 configured to create a calibration pattern with an exposure beam that can be scanned in a scanning direction. Examples of such a printing device 1 are also shown in Figure 1 and Figure 4 The printing device 1 is configured to perform printing according to calibration pattern printing data. The calibration pattern has a plurality of exposed lines and unexposed lines extending in a scanning direction, and the plurality of exposed lines and unexposed lines have different line widths and different distances to adjacent lines.

[0095] The system 70 for obtaining a compensation pattern for a workpiece pattern forming device also includes a measuring device 4, which is arranged to measure the line width of a line in a scan direction perpendicular to the scan direction in a printed calibration pattern. In the illustration, the measuring device 4 is illustrated as a separate unit arranged on a support 30 of the printing device 1. However, the measuring device 4 can also be arranged as a completely separate unit, or as an integrated part of the printing head 32. Such a measuring device 4 is well known in the prior art and can be obtained in many different configurations. However, as long as the measuring device provides the line width of a line in the scan direction or data from which such an edge position can be derived, the details of the measuring device 4 are not necessary and will therefore not be described further.

[0096] The system 70 for obtaining a compensation pattern for a workpiece patterning device further comprises a processing device 6. The processing device 6 is connected to the printing device 1 and the measuring device 4. The processing device 6 is configured for calculating a deviation of a measured line width of a line relative to an expected line width of an edge from the calibration pattern printing data.

[0097] The processing device 6 is further configured to calculate line width compensation data based on the calculated deviation, the line width compensation data being used to adapt the line width of the pattern printing data before printing to compensate for the calculated deviation. The line width compensation data is associated with at least the expected line width and whether the line is an exposed line or an unexposed line.

[0098] In one embodiment, the processing device is further configured to determine a proximity indicator for each line in the calibration pattern. The proximity indicator is a parameter representing an average fraction of exposed or unexposed areas in the surroundings of the line in the calibration pattern. The line width compensation data is further associated with the proximity indicator.

[0099] In one embodiment, the proximity indicator is a line-dense classification having at least two categories.

[0100] In another embodiment, the proximity indicator is a line density metric.

[0101] Fig.15AAn embodiment of an apparatus 80 for processing printing data defining a pattern to be printed is schematically shown. The apparatus 80 for processing printing data defining a pattern to be printed comprises a processing circuit 8 and a memory 7. The memory 7 comprises instructions executable by the processing circuit 8, whereby the processing circuit 8 is operable to obtain printing data for the pattern to be printed and to identify lines in a scanning direction in the pattern to be printed. When the instructions are executed by the processing circuit 8, the instructions cause the processing circuit 8 to further determine line attributes of the lines and to derive line width adjustment values ​​for each identified line from line width compensation data. The line attributes include at least the line width and whether the line is an unexposed line or an exposed line. The line width compensation data is obtained by the method described above and is based on the determined line width and whether the line is an unexposed line or an exposed line. When the instructions are executed by the processing circuit 8, the processing circuit 8 is operable to further adapt the printing data defining the identified line according to the line width adjustment value to printing data for line width compensation. The line width compensation data is obtained by the system 70 for obtaining a compensated pattern, for example, according to Fig.14 Embodiment of the invention.

[0102] In one embodiment, the processing circuitry 8 is operable to adapt the print data in the bitmap domain by adjusting the intensity of the respective bits at or immediately adjacent each edge of the line to be adjusted to achieve a sum of respective line edge position adjustments equal to an amount of the derived line width adjustment value.

[0103] In one embodiment, the processing circuit 8 is configured to derive the line width adjustment value by interpolating using the line width adjustment values ​​from the line width compensation data corresponding to the closest larger line width and the closest smaller line width.

[0104] In one embodiment, the line attributes further include a proximity indicator. The proximity indicator is a parameter representing the average fraction of exposed or unexposed areas in the surroundings of the line. The line width compensation data is further associated with the proximity indicator.

[0105] In another embodiment, the proximity indicator is a line-dense classification having at least two categories.

[0106] In another embodiment, the proximity indicator is a line density measurement, wherein the processing circuit is operable to derive the line width adjustment value by interpolating using width adjustment values ​​from line width compensation data corresponding to the closest larger line density measurement and the closest smaller line density measurement.

[0107] exist Fig.15A In FIG. 8 , the device 80 for processing the printing data defining the pattern to be printed is shown as a separate unit, communicating with the system 70 to obtain the compensation pattern. Fig. 15BA device 80 for processing printing data defining a pattern to be printed, schematically shown in FIG. 8 , may also be provided as part of the system 70 for obtaining a compensation pattern and / or integrated in the system 70 . Preferably, the processing circuit 8 forms part of the processing device 6 .

[0108] Fig.16 An embodiment of a printing device 1 is schematically shown. The printing device 1 comprises a device 9 for processing line width compensated printing data, which is obtained by a device 80 for processing printing data according to the above-mentioned idea. The printing device 1 is a printing device of a system 70 for obtaining a compensation pattern for a workpiece pattern forming device. The printing device 1 comprises a printing head 32, which has at least one exposure beam that can be scanned in a scanning direction. The printing device 1 also comprises a control unit 5. The control unit 5 is arranged to control the operation and relative movement of the printing head based on the line width compensated printing data.

[0109] exist Fig.14 In the embodiment of the present invention, the control unit 5 and the device 9 for processing edge-compensated printing data are shown as separate units. However, they can also be integrated into a common unit. Furthermore, the processing circuit of the device 80 for processing printing data can be integrated in the same unit as the control unit 5 and / or the device 9 for processing edge-compensated printing data. Furthermore, the processing device 6 can be part of a common unit.

[0110] The above embodiments should be understood as several illustrative examples of the present invention. Those skilled in the art will appreciate that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different partial solutions in different embodiments may be combined in other configurations where technically possible. However, the scope of the present invention is limited by the appended claims.

[0111] Appendix - Sliding Window Routines

[0112]

[0113]

Claims

1. A method for obtaining line width compensation data for a workpiece pattern forming device, comprising the following steps: - printing (S2) a calibration pattern with an exposure beam (32) that can be scanned in a scanning direction (Y); performing the printing according to the calibration pattern printing data (S2); The calibration pattern has a plurality of exposed lines and unexposed lines extending in the scanning direction (Y), the plurality of exposed lines and unexposed lines having different line widths and different distances to adjacent lines; - measuring (S4) the line width of the line in the printed calibration pattern in a scanning direction (X) perpendicular to the scanning direction (Y); - calculating (S6) a deviation of the measured line width of the line relative to the expected line width of the line based on the calibration pattern printing data; - calculating (S8) line width compensation data (123, 126) based on the calculated deviation, the line width compensation data being used to adapt the line width of the pattern printing data before printing to compensate for the calculated deviation; the line width compensation data (123, 126) being associated with at least an expected line width and information about whether the line is an exposed line or an unexposed line.

2. The method according to claim 1, characterized in that The following steps are also included: - determining (S7) a proximity indicator for each of said lines in said calibration pattern; The proximity indicator is a parameter representing the ratio between the distance (119) to the nearest neighboring line and the line width (114); and Wherein the line width compensation data is further associated with the proximity indicator.

3. A method for obtaining printing data for line width compensation, comprising the following steps: - obtaining (S10) printing data of a pattern to be printed; - identifying (S12) lines in the pattern to be printed in the scanning direction (Y); - determining (S14) line properties of the line, the line properties comprising at least a line width and information on whether the line is an unexposed (116; 116B) line or an exposed (110; 110B) line; - deriving (S16) a line width adjustment value for each identified line from line width compensation data (123, 126) obtained by the method according to claim 1 based on the determined line width and information about whether the line is an unexposed line (116, 116B) or an exposed line (110; 110B); as well as - adapting (S18) said printing data defining the identified line to line width compensated printing data according to said line width adjustment value.

4. The method according to claim 3, characterized in that: performing said adapting of said printing data in a bitmap domain (S18); The intensity of individual bits (90) at or immediately adjacent each edge (84) of the line to be adjusted is adjusted to achieve a sum of respective line edge position adjustments equal to an amount of the derived line width adjustment value.

5. The method according to claim 3 or 4, characterized in that: The derivation (S16) of the line width adjustment value includes interpolation using the line width adjustment value from the line width compensation data corresponding to the closest larger line width and the closest smaller line width.

6. The method according to any one of claims 3 to 5, characterized in that The line attributes also include a proximity indicator; The proximity indicator is a parameter representing the ratio between the distance (119) to the nearest neighboring line and the line width (114); and Wherein the line width compensation data is further associated with the proximity indicator.

7. A method for printing a pattern, comprising the steps of: - obtaining (S20) line width compensated printing data of a pattern to be printed, the line width compensated printing data being obtained by the method according to claim 3; and - controlling (S22) a printing process of a workpiece (20) at least partially covered with a layer sensitive to electromagnetic or electronic radiation based on the line width corrected printing data.

8. The method according to claim 7, characterized in that The step of controlling (S22) the printing process includes controlling the exposure beams (34) to operate simultaneously to provide micro scanning in a scanning direction (Y) while being scanned in a scanning direction (X) perpendicular to the scanning direction (Y) to create scanning strips.

9. The method according to claim 8, characterized in that The step of controlling (S22) the printing process further comprises creating a plurality of the scanning swaths shifted in the scanning direction.

10. A system (70) for obtaining line width compensation data for a workpiece patterning device, comprising: - a printing device (1) configured to create a calibration pattern with an exposure beam (34) that can be scanned in a scanning direction (Y); The printing device (1) is configured to perform the printing according to calibration pattern printing data; The calibration pattern has a plurality of exposed lines (110; 110B) and unexposed lines (116; 116B) extending in the scanning direction (Y), the plurality of exposed lines and unexposed lines having different line widths and different distances to adjacent lines; - a measuring device (4) arranged for measuring the line width of said lines in the printed calibration pattern in a scanning direction (X) perpendicular to said scanning direction (Y); as well as - a processing device (6) configured to calculate, from the calibration pattern printing data, a deviation of the measured line width of the line relative to an expected line width of the line; The processing device (6) is further configured to calculate line width compensation data based on the calculated deviation, the line width compensation data being used to adapt the line width of the pattern printing data before printing to compensate for the calculated deviation; The line width compensation data is associated with at least an expected line width and information about whether the line is an exposed line (110; 110B) or an unexposed line (116; 116B).

11. The system according to claim 10, characterized in that The processing device (6) is further configured to determine a proximity indicator for each of the lines in the calibration pattern; The proximity indicator is a parameter representing an average fraction of exposed (118) or unexposed (112) areas in the surroundings of the line in the calibration pattern; and Wherein the line width compensation data is further associated with the proximity indicator.

12. A device (80) for processing printing data defining a pattern to be printed, comprising: - a processing circuit (8); as well as - memory (7); The memory (7) comprises instructions executable by the processing circuit (8), whereby the processing circuit (8) is operable to: obtaining printing data for a pattern to be printed; identifying lines (110, 110B; 116, 116B) in a pattern to be printed in a scanning direction; determining line properties of the line (110, 110B; 116, 116B), the line properties comprising at least a line width and information about whether the line is an unexposed line (116, 116B) or an exposed line (110, 110B); deriving a line width adjustment value for each identified line from line width compensation data obtained by the method according to claim 1 based on the determined line width and information about whether the line is an unexposed line (116, 116B) or an exposed line (110, 110B); as well as The print data defining the identified line is adapted to line width compensated print data according to the line width adjustment value.

13. The device according to claim 12, wherein: The processing circuitry (8) is operable to adapt the print data in a bitmap domain, wherein the intensity of individual bits (90) at or immediately adjacent each edge (84) of a line to be adjusted is adjusted to achieve a sum of corresponding line edge position adjustments by an amount equal to the derived line width adjustment value.

14. The device according to claim 12 or 13, characterized in that The processing circuit (8) is operative to derive a line width adjustment value by interpolating using line width adjustment values ​​from the line width compensation data corresponding to the closest larger line width and the closest smaller line width.

15. A printing device (1), comprising: - a device (6) for processing line width compensated printing data, the line width compensated printing data being obtained by the device for processing printing data according to claim 12; wherein the printing device (1) is the printing device (1) of the system (70) for obtaining a compensation pattern for a workpiece patterning device according to claim 10; a printing head (32) having an exposure beam (34) which can be scanned in a scanning direction (Y); as well as - a control unit (5); The control unit (5) is arranged to control the operation and relative movement of the print head (32) based on the line width compensated printing data.

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