CN113467194A - Ambient temperature compensation method, alignment device and direct-writing imaging photoetching equipment - Google Patents
Ambient temperature compensation method, alignment device and direct-writing imaging photoetching equipment Download PDFInfo
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
- G03F7/70858—Environment aspects, e.g. pressure of beam-path gas, temperature
- G03F7/70866—Environment aspects, e.g. pressure of beam-path gas, temperature of mask or workpiece
- G03F7/70875—Temperature, e.g. temperature control of masks or workpieces via control of stage temperature
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
- G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
- G03F9/7073—Alignment marks and their environment
Abstract
The invention provides an environmental temperature compensation method of an alignment device, wherein the alignment device comprises a camera, a calibration scale and a platform for fixing the calibration scale, and the environmental temperature compensation method comprises the following steps: s101: aligning a first identification mark on a calibration scale with the center of the camera view at an ambient temperature to obtain a first position of the platform; s102: aligning a second identification mark on the calibration scale with the center of the camera view to obtain a second position of the platform; s103: determining the distance between the first identification mark and the second identification mark according to the first position and the second position of the platform; s104: changing the ambient temperature, and determining the distance between the first identification mark and the second identification mark at different ambient temperatures; s105: and obtaining the relation between the temperature compensation value and the ambient temperature based on the distances between the first identification mark and the second identification mark at a plurality of ambient temperatures. By adopting the technical scheme of the invention, the exposure precision error caused by the change of the environmental temperature can be reduced, the exposure precision is improved, and the occurrence of the exposure reject ratio is reduced.
Description
Technical Field
The present disclosure relates to the field of direct imaging technologies, and in particular, to an ambient temperature compensation method, an alignment apparatus, and a direct imaging lithography apparatus.
Background
With the rapid development of electronic products, the requirement on the printing precision of a circuit board is higher and higher, the traditional film substrate type exposure machine cannot deal with the problem of expansion and shrinkage of the negative caused by the environment, and the printing requirement on the circuit board with higher precision is difficult to deal with. The direct-writing laser exposure machine gradually occupies the PCB printing industry due to the advantages that the direct-writing laser exposure machine does not need a film negative film and has various alternative alignment and expansion modes.
And a Direct writing Laser exposure machine (LDI) captures a target point according to preselected Mark point information in the printed material number, calculates a harmomegathus matrix by using the captured Mark point information, transforms a PCB (printed Circuit Board) graph in the printed material number by using the obtained harmomegathus matrix, finally prints the PCB graph on a substrate, and forms a circuit board by processes of development, etching and the like. In practice, because a large amount of heat is generated during the operation of the equipment and cannot be removed in time, the temperature of the exposure chamber cannot be kept relatively stable; some sites with severe environment do not have cooling measures, and the temperature rise and the temperature reduction inevitably cause thermal expansion and cold contraction of the PCB substrate, so that the alignment is inaccurate and the exposure is poor, and therefore calibration compensation is necessary for the influence of the temperature on the exposure precision, so that the alignment exposure precision is improved and the exposure yield is improved.
The statements in this background section merely represent techniques known to the public and are not, of course, representative of the prior art.
Disclosure of Invention
In view of at least one of the drawbacks of the prior art, the present invention provides an ambient temperature compensation method for an alignment apparatus, the alignment apparatus including a camera, a calibration scale, and a platform for fixing the calibration scale, the ambient temperature compensation method including:
s101: aligning a first identification mark on the calibration scale with the center of the camera view at ambient temperature to obtain a first position of the platform;
s102: aligning a second identification mark on the calibration scale with the center of the camera view to obtain a second position of the platform;
s103: determining the distance between the first identification mark and the second identification mark according to the first position and the second position of the platform;
s104: changing the ambient temperature, and determining the distance between the first identification mark and the second identification mark at different ambient temperatures;
s105: and obtaining the relation between the temperature compensation value and the ambient temperature based on the distances between the first identification mark and the second identification mark at a plurality of ambient temperatures.
According to an aspect of the invention, further comprising: and moving the platform, adjusting the calibration scale to the focal plane of the camera, and then keeping the distance between the camera and the calibration scale along the optical axis direction of the camera.
According to an aspect of the present invention, wherein the step S101 comprises:
moving the first identifying mark into the field of view of the camera at the ambient temperature;
acquiring an image of the first identification mark, and obtaining a first distance between the first identification mark and the center of the camera view;
when the first distance is larger than a preset deviation value, moving the platform until the first distance is smaller than the preset deviation value, and recording the position of the platform at the moment as the first position;
according to an aspect of the present invention, wherein the step S102 comprises:
moving the second identifying indicia into the field of view of the camera;
acquiring an image of the second identification mark, and obtaining a second distance between the second identification mark and the center of the camera view;
and when the second distance is greater than the preset deviation value, moving the platform until the second distance is less than the preset deviation value, and recording the position of the platform at the moment as the second position.
According to an aspect of the invention, wherein the distance is a euclidean distance.
According to an aspect of the present invention, wherein the step S104 comprises: changing the ambient temperature, and determining the distance between the first identification mark and the second identification mark at different ambient temperatures by repeating the steps S101, S102 and S103.
According to an aspect of the present invention, wherein the step S104 comprises:
changing the ambient temperature, moving the platform to the first position, and recording a first offset value of the center of the first identification mark and the center of the camera view;
moving the platform to the second position, and recording a second offset value of the center of the second identification mark and the center of the camera view;
calculating distances of the first identifying mark and the second identifying mark at a plurality of ambient temperatures based on the first position, the first offset value, the second position, and the second offset value.
According to an aspect of the present invention, wherein the step S105 comprises:
selecting one environmental temperature from the plurality of environmental temperatures as a reference environmental temperature, and taking the distance between the first identification mark and the second identification mark at the environmental temperature as a reference distance;
and calculating temperature compensation values at different environmental temperatures based on the reference distance and the distances between the first identification mark and the second identification mark at different environmental temperatures.
According to an aspect of the present invention, wherein the step S105 comprises: and obtaining the relation between the temperature compensation value and the ambient temperature through a least square method based on the ambient temperature and the temperature compensation value.
According to an aspect of the invention, wherein the alignment device is a direct imaging lithography device for manufacturing a PCB substrate, the ambient temperature compensation method further comprises:
s106: measuring an exposure chamber temperature of the direct imaging lithography apparatus;
s107: obtaining a temperature compensation value corresponding to the temperature of the exposure chamber according to the temperature of the exposure chamber based on the relation between the temperature compensation value and the ambient temperature;
s108: and performing compensation transformation on the PCB drawing based on the temperature compensation value.
According to one aspect of the invention, the shape, size and color of the two identification marks remain the same.
The invention also designs an aligning device, which comprises:
a platform;
the calibration ruler is fixed on the platform;
a camera disposed above the platform and configured to capture an image of the calibrated scale;
a control unit in communication with the platform and the camera and configured to perform the ambient temperature compensation method as described above.
According to one aspect of the invention, further comprising an exposure chamber, the control unit being in communication with the exposure chamber and further configured to adjust or read an ambient temperature of the exposure chamber.
The invention also relates to a direct imaging lithographic apparatus, comprising an alignment device as described above, configured to: and performing compensation transformation on the PCB drawing based on the temperature compensation value corresponding to the real-time environment temperature, and printing the PCB drawing on the PCB substrate.
By adopting the technical scheme of the invention, after the alignment of the direct imaging photoetching equipment is finished, the corresponding compensation value at the moment is automatically calculated according to the real-time temperature value of the exposure chamber and the temperature compensation value formula acquired by the equipment at the moment, and the compensation value is compensated into the PCB matrix relational expression after the alignment, so that the problem of expansion and shrinkage deviation caused by the temperature change of the exposure chamber can be reduced, the exposure precision of the direct imaging photoetching equipment is improved, and the occurrence of exposure reject ratio is reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure. In the drawings:
FIG. 1 shows a schematic view of a registration apparatus of one embodiment of the present invention;
FIG. 2 shows a flow diagram of an ambient temperature compensation method of one embodiment of the present invention;
FIG. 3 depicts a schematic view of a direct imaging lithographic apparatus according to one embodiment of the present invention.
Detailed Description
In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection, either mechanically, electrically, or in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.
The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.
The invention provides an environmental temperature compensation method for a positioning device, which is characterized in that for a calibrated platform, the Euclidean distance between two fixed mark patterns on a calibration scale is captured and identified through a single camera, and then the Euclidean distance is compared with a reference value to obtain a temperature compensation value under the current environmental temperature. And finally, compensating the compensation value into the PCB matrix relational expression after alignment, so that the problem of expansion and shrinkage deviation caused by the temperature change of the exposure chamber can be reduced, the exposure precision of the direct imaging lithography equipment is improved, and the exposure reject ratio of the PCB substrate is reduced.
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
Fig. 1 shows a schematic diagram of an alignment apparatus 10 according to an embodiment of the present invention, which includes a camera 11, a calibration scale 12, and a platform 13 for fixing the calibration scale 12. The alignment device 10 may be included as part of a direct imaging lithographic apparatus. The camera 11 is disposed above the platform 13, for example, the aligning device 10 further includes a guide rail 14, and the camera 11 is disposed on the guide rail 14 and can move left and right along the guide rail 14 so as to capture an image (for example, the identification mark 15 on the calibration scale 12 or the positioning mark on the PCB substrate) during actual exposure. If the alignment apparatus 10 (e.g. a direct imaging lithography apparatus) comprises a left camera and a right camera, either one may be selected as the camera 11, preferably the camera 11 is a CCD camera. The calibration ruler 12 is provided with a row of identification marks 15, such as 15-1, 15-2, … …, 15-n, and usually has a marking pattern with various marking accuracies, such as a solid circle, a hollow circle, a square, a circle, a cross, a rectangle, and other design patterns, which can be used as reference points for calibration alignment. The scaling rule 12 is fixed on the platform 13 and can move along the X-axis, the Y-axis and the Z-axis along the platform 13, wherein the X-axis and the Y-axis are mutually vertical axes in a horizontal plane, and the Z-axis is a vertical axis. The stage 13 is movable along the X-axis and the Y-axis with high precision, and has an adaptive compensation function to ensure straightness and orthogonality, for example, a positioning error of + -5 μm. In addition, the identification mark 15 may be located on the platform 13, and the present invention does not limit the location of the identification mark 15.
Fig. 2 shows a flowchart of an ambient temperature compensation method according to an embodiment of the present invention, which can be implemented by the alignment apparatus 10 shown in fig. 1, and is described in detail below with reference to fig. 1 and 2. The ambient temperature compensation method 100 includes:
in step S101: at ambient temperature T0, the first identifying mark, e.g., 15-1, on the scale 12 is aligned with the center of the camera's field of view to obtain the first position P1 of the platform 13 at that time. Wherein, T0 may be room temperature, or any temperature value within the working temperature range of the alignment apparatus 10, for example, any temperature value within-10 ℃ to 40 ℃.
Before the compensation value is calculated for the ambient temperature, it is preferable to ensure that all parts in the alignment device 10 are at the same temperature, the related calibration is completed, and the calibration ruler is kept clean. To ensure the accuracy of the temperature compensation, according to a preferred embodiment of the present invention, the ambient temperature compensation method 100 further comprises: the platform 13 is moved to adjust the calibration scale 12 to the focal plane of the camera 11, and then the distance between the camera 11 and the calibration scale 12 in the optical axis direction of the camera, that is, the relative distance between the camera 11 and the calibration scale 12 in the Z-axis direction is kept constant. The adjustment of the calibration scale 12 to the focal plane of the camera 11 is to ensure the image sharpness of the camera 11 when capturing the identification mark 15, so as to reduce errors caused by poor sharpness. Because the image shot by the camera 11 is clearest at the focal plane position, the image recognition processing is facilitated. Specifically, the platform 13 on which the calibration scale 12 is located is moved in the Z-axis direction, the camera 11 captures the identification mark 15 in the camera view and performs image recognition, for example, after determining that the identification mark 15 has been adjusted to the focal plane of the camera 11 according to the imaging quality, the position of the camera 11 on the guide rail 14 is fixed, and the corresponding Z-axis coordinate position of the platform 13 is fixed. According to a preferred embodiment of the present invention, the aligning device 10 further comprises an image processing unit (not shown) which communicates with the camera 11 to obtain the image captured by the camera 11 and performs image processing to determine the sharpness of the image. Preferably, the alignment device 10 further includes a light source 16, and the light source 16 has a plurality of switchable light sources, and the integration time is adjustable to adapt to the image quality of the correction camera under different ambient lights.
The method comprises the steps of wiping dust and the like on the surface of the calibration scale 12 with alcohol, turning on the camera 11 to find a light source with relatively better imaging by using different light sources in the light source 16, adjusting the Z axis to enable the calibration scale 12 on the platform 13 to be in the optimal focal plane position, fixing the position of the camera 11 on the guide rail 14 and fixing the Z axis coordinate position corresponding to the platform 13, wherein the operations can be executed in step S101 or can be executed in preparation work before the ambient temperature compensation method 100, and the operations are all within the protection scope of the invention.
To obtain a more accurate first position P1, the deviation of the pixel coordinates of the first recognition mark center 15-1 from the pixel coordinates of the camera view center needs to be corrected. For each camera 11, the pixels at which it takes an image are typically fixed. A camera pixel coordinate system may be established in pixels based on the field of view of the camera 11. For example, the upper left corner of the picture captured by the camera 11 may be set as the origin of the camera pixel coordinate system, the pixel coordinates C (x, y) of the center of the camera image are (camera width pixel/2, camera height pixel/2), and if the camera resolution is 1920 × 1080, the center pixel of the image captured by the camera 11 is (960,540).
According to a preferred embodiment of the present invention, first, the first recognition mark 15-1 is moved into the field of view of the camera 11 at the ambient temperature T0. Then, an image of the first recognition mark 15-1 is captured by the camera 11, and a first distance (e.g., in pixels) between the center of the first recognition mark 15-1 and the center of the camera view is obtained; when the first distance is greater than the predetermined offset value, the platform 13 is moved until the first distance is less than the predetermined offset value, and finally the position of the platform 13 at this time is recorded as the first position P1. Specifically, an image of the first recognition mark 15-1 is acquired by the camera 11, and the pixel coordinate of the center of the first recognition mark 15-1 is acquired by the image processing device, and when a deviation value of the pixel coordinate of the center of the first recognition mark 15-1 from the pixel coordinate of the center of the camera field of view, that is, a first distance, is greater than a preset deviation value (for example, 0.1 pixel), the deviation value of the pixel coordinate is converted to an actual deviation value based on the actual object size corresponding to a single pixel, and the stage 13 is moved in accordance with the actual deviation value to eliminate the deviation. And then, recognizing the deviation value of the pixel coordinate of the center of the first recognition mark 15-1 and the pixel coordinate of the camera view field center through image acquisition and image processing again, moving the platform 13, and repeating the operation until the deviation value is smaller than a preset deviation value, wherein the center of the first recognition mark 15-1 is approximately aligned with the camera view field center, and the position of the platform 13 is taken as a first position P1, so that the precision is high, and the influence on the measurement and calculation of the ambient temperature compensation value is small.
In the above embodiment, the center of the first recognition mark 15-1 is aligned with the center of the camera view, but the present invention is not limited thereto, and other reference points of the first recognition mark 15-1 may be selected for alignment. Preferably, if the identification mark 15 is a circular pattern, the center of the circle may be aligned with the center of the camera view as a reference point; if the recognition mark 15 is a rectangular pattern, the geometric center or any of the vertices of the four corners may be aligned with the camera visual field center as a reference point, and if the recognition mark 15 is another figure, the geometric center or other points may be selected to be aligned with the camera visual field center. Since the smaller the error range after alignment, the higher the alignment accuracy, the more the feature points on the recognition mark 15 are selected as much as possible, which contributes to the improvement of the alignment accuracy.
In step S102: the second position P2 of the platform 13 is obtained by aligning a second identification mark, such as the identification mark 15-2, on the scale 12 with the center of the camera's field of view.
To obtain the more accurate second position P2, it is necessary to correct the deviation of the pixel coordinates of the center of the second recognition mark 15-2 from the pixel coordinates of the center of the camera image. The second identification mark 15-2 may be any one of the identification marks on the scale 12 as long as it is different from the first identification mark 15-1. According to a preferred embodiment of the invention, the method of correcting the deviation is: first, the second recognition mark 15-2 is moved into the field of view of the camera 11; then, an image of the second recognition mark 15-2 is acquired, a second distance between the center of the second recognition mark 15-2 and the center of the camera view is obtained, when the second distance is greater than a preset deviation value, the platform 13 is moved until the second distance is smaller than the preset deviation value, and the position of the platform at this time is recorded as a second position P2. The correction method is the same as the method for correcting the first position P1, and is not described herein again.
In step S103: the distance between the center of the first recognition mark 15-1 and the center of the second recognition mark 15-2 is determined according to the first position P1 and the second position P2 of the platform 13. At this time, the Z-axis coordinate position of the platform 13 is fixed, the distance L0 between the first position P1 and the second position P2 on the plane formed by the X-axis and the Y-axis is P2-P1, L0 is the distance difference between the first position P1 and the second position P2 at the time of the ambient temperature T0, and the temperature compensation value C0 at this time is set to 0 with L0 as a reference, that is, no compensation is performed at the time of the ambient temperature T0, and compensation needs to be performed with respect to L0 at other ambient temperatures.
In step S104: the ambient temperature is changed and the distance between the center of the first recognition mark 15-1 and the center of the second recognition mark 15-2 at different ambient temperatures is determined. Specifically, by changing the ambient temperature, for example, a series of temperature values may be taken within the operating temperature range of the alignment device 10, for example, values between-10 ℃ and 40 ℃ at intervals of 1 ℃ are taken, and the distance value L between the first position P1 and the second position P2 at each temperature value is obtained in turn. The smaller the interval of the temperature values is, the more the number of the obtained distance values is, and the higher the accuracy of the finally measured ambient temperature compensation value is. Of course, it is within the scope of the present invention to select temperature values at larger intervals or to take a set of discrete temperature values within the operating temperature range in order to improve the efficiency of the measurement.
According to a preferred embodiment of the present invention, the ambient temperature is changed, and the distance L between the center of the first recognition mark 15-1 and the center of the second recognition mark 15-2 at different ambient temperatures is determined by repeating the steps S101, S102, and S103. After the ambient temperature is changed, the offset value needs to be corrected each time the first position P1 and the second position P2 are acquired, because the platform 13 is directly moved, so that the accuracy of aligning the first recognition mark 15-1 and the second recognition mark 15-2 to the center of the camera field of view is low, the camera 11 captures and performs image recognition, and then the platform 13 is continuously moved according to the offset value, so that the accuracy of the first position P1 and the second position P2 can be improved, and the accuracy of the distance L is further improved.
According to another preferred embodiment of the present invention, the platform 13 is moved to a first position P1 by changing the ambient temperature, and a first offset value Δ P1 of the center of the first signature center 15-1 from the center of the camera's field of view is recorded; moving the platform 13 to a second position P2, and recording a second offset value delta P2 between the center of the second identification mark center 15-2 and the center of the camera view; the distance L between the center of the first identifying mark 15-1 and the center of the second identifying mark 15-2 at a plurality of ambient temperatures is calculated based on the first position P1, the first offset value Δ P1, the second position P2, and the second offset value Δ P2. For example, after the ambient temperature is changed to T1, the platform 13 is moved to the first position P1 corresponding to the ambient temperature T0, the camera 11 captures and performs image recognition to obtain the pixel deviation value between the center of the first recognition mark 15-1 and the camera view center at that time, the pixel deviation value is converted to the actual deviation value, i.e., the first deviation value Δ P1, based on the actual object size corresponding to a single pixel, the platform 13 is moved to the second position P2 corresponding to the ambient temperature T0, the camera 11 captures and performs image recognition to obtain the pixel deviation value between the second recognition mark center 15-2 and the camera view center at that time, and the pixel deviation value is converted to the actual deviation value, i.e., the second deviation value Δ P2, based on the actual object size corresponding to a single pixel. The distance value L0 at the ambient temperature T0 is added to Δ P1 and Δ P2, which is the distance value L1 at the ambient temperature T1, i.e., L1 ═ P1 +/Δ P1+ P2 +/Δ P2. And the analogy is repeated to obtain a series of distance values L under a plurality of environmental temperatures.
According to a preferred embodiment of the invention, the distance value L is the euclidean distance. According to one embodiment, after changing the ambient temperature, the first position P1 and the second position P2 are first determined, and then the Euclidean distance L between P1 and P2, i.e., the straight-line distance between the center of the first recognition mark 15-1 and the center of the second recognition mark 15-2, is calculated. According to another embodiment, after changing the ambient temperature, the first offset value Δ P1 and the second offset value Δ P2 are determined first, because the change of scale and shrinkage caused by the change of the ambient temperature can be multidirectional, so the first offset value Δ P1 and the second offset value Δ P2 are vector values, and when calculating the euclidean distance L between the center of the first identification mark 15-1 and the center of the second identification mark 15-2, the first position P1, the second position P2, the first offset value Δ P1 and the second offset value Δ P2 are all decomposed to the X axis and the Y axis, and the euclidean distance L is obtained after the sum calculation.
In step S105: and obtaining the relation between the temperature compensation value C and the ambient temperature T based on the distances L between the first identification mark and the second identification mark at a plurality of ambient temperatures.
According to a preferred embodiment of the present invention, one ambient temperature is selected from among a plurality of ambient temperatures as the reference ambient temperature T0, and the distance between the center of the first recognition mark 15-1 and the center of the second recognition mark 15-2 at the ambient temperature is taken as the reference distance L0; the temperature compensation values C at different ambient temperatures T are calculated based on the reference distance L0 and the distance L between the center of the first recognition mark 15-1 and the center of the second recognition mark 15-2 at different ambient temperatures. Specifically, based on n ambient temperatures [ T0, T1, T2, ……，Tn]Obtaining a set of Euclidean distances [ L0, L1, L2, … …, Ln [ ]]One ambient temperature is selected from the n ambient temperatures as a reference ambient temperature T0, for example, room temperature or an ambient temperature before the temperature is artificially changed, a distance between the corresponding first position P1 and the second position P2 is used as a reference distance L0, and then the compensation value C is calculated with L0 as a reference. For example, when the ambient temperature is T0, the euclidean distance is L0, and the temperature compensation value is C0; when the ambient temperature is T1, the Euclidean distance is L1, and the temperature compensation value C1 is L0-L1; when the ambient temperature is T2, the Euclidean distance is L2, and the temperature compensation value C2 is L0-L2; by analogy, a group of temperature compensation values [ C0, C1, C2, … …, Cn ] are obtained]And further obtaining the corresponding relation between the environment temperature and the temperature compensation value, which can be expressed as a matrix
Wherein C0 is 0.
According to a preferred embodiment of the present invention, the relationship between the temperature compensation value C and the ambient temperature T is obtained by a least square method based on the ambient temperature T and the temperature compensation value C. In particular, by pairing matrices
And performing least square fitting to obtain a linear relation C between the temperature compensation value C and the ambient temperature T, wherein k is a coefficient and b is a constant. In practical application, the exposure accuracy can only be improved to a limited extent if the temperature compensation value closest to the measured ambient temperature cannot be found in the matrix because of the limitation of the n values of the n ambient temperatures during measurement. And the corresponding compensation value is directly calculated through the linear relation, so that the problem of exposure deviation caused by the change of the ambient temperature can be greatly reduced.
According to a preferred embodiment of the invention, the shape, size and colour of the two identification marks 15 remain identical. That is, the first recognition mark 15-1 and the second recognition mark 15-2 are selected to be the same identification pattern, so as to maintain consistency when the camera captures and performs image processing recognition, thereby improving recognition accuracy.
How to obtain the linear relationship C ═ kT + b between the temperature compensation value C and the ambient temperature T in the ambient temperature compensation method 100 is described in detail above by steps S101 to S105. The application of the linear relationship to the ambient temperature compensation method 100 is described further below.
According to a preferred embodiment of the present invention, wherein the alignment apparatus 10 is a direct imaging lithography apparatus for manufacturing PCB substrate, referring to fig. 3, the direct imaging lithography apparatus comprises an exposure chamber 18, and the ambient temperature compensation method 100 further comprises:
in step S106: the temperature of the exposure chamber 18 of the direct imaging lithography apparatus is measured, for example the direct imaging lithography apparatus further comprises a temperature sensor, which may acquire the temperature of the exposure chamber 18 in real time.
In step S107: and obtaining a temperature compensation value C corresponding to the exposure chamber temperature according to the measured exposure chamber temperature based on the relational expression C of the temperature compensation value C and the environment temperature T, wherein the relational expression C is kT + b. Where C ═ kT + b is a linear function derived from the least squares method, k is a coefficient, and b is a constant.
In step S108: and performing compensation transformation on the PCB drawing based on the temperature compensation value C. And confirming a conversion matrix of the coordinate system where the camera 11 is located and the exposure coordinate system, and transforming the PCB graph based on the Euclidean distance corresponding to the temperature compensation value C so as to improve the printing precision.
After the direct imaging photoetching device completes alignment, a compensation value corresponding to the moment is automatically calculated according to the real-time temperature value of the exposure chamber collected at the moment and a formula of the temperature compensation value and the environment temperature, and the compensation value is compensated into a PCB matrix relational expression after alignment, so that the problem of expansion and shrinkage deviation caused by the temperature change of the exposure chamber can be solved, the exposure precision of the direct imaging photoetching device is improved, and the exposure reject ratio of the PCB is reduced.
In summary, with the ambient temperature compensation method 100, after the temperature compensation relational expression is obtained by simulating the variation of the substrate PCB with the variation of the substrate PCB fixed at the fixed length 12 at different temperatures in steps S101 to S105, the relational expression is used to compensate the variation of the substrate PCB with the variation of the substrate PCB in steps S106 to S108, so as to solve the problem that the variation of the ambient temperature affects the exposure accuracy. Preferably, the calibration ruler 12 is a special calibration piece, and the main material of the calibration piece is the same as that of the PCB substrate, so as to ensure that the expansion and contraction rate of the calibration piece is the same as that of the PCB substrate.
The present invention further provides an aligning apparatus 10, as shown in fig. 3, the aligning apparatus 10 includes:
a platform 11;
a calibration ruler 12 fixed on the platform 13;
a camera 11 disposed above the platform 13 and configured to capture an image of the scale 12;
a control unit 17 in communication with the platform 13 and the camera 11 and configured to perform the ambient temperature compensation method 100 as described above.
According to a preferred embodiment of the present invention, further comprising an exposure chamber 18, said control unit 17 being in communication with said exposure chamber 18 and being further configured to adjust or read the ambient temperature of said exposure chamber 18.
The invention also contemplates a direct imaging lithographic apparatus 1, as described above with reference to fig. 3, comprising an alignment fixture 10 configured to: and performing compensation transformation on the PCB drawing based on the temperature compensation value corresponding to the real-time environment temperature, and printing the PCB drawing on the PCB substrate.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (14)
1. An ambient temperature compensation method for an alignment device, the alignment device comprising a camera, a calibration scale and a platform for fixing the calibration scale, the ambient temperature compensation method comprising:
s101: aligning a first identification mark on the calibration scale with the center of the camera view at ambient temperature to obtain a first position of the platform;
s102: aligning a second identification mark on the calibration scale with the center of the camera view to obtain a second position of the platform;
s103: determining the distance between the first identification mark and the second identification mark according to the first position and the second position of the platform;
s104: changing the ambient temperature, and determining the distance between the first identification mark and the second identification mark at different ambient temperatures;
s105: and obtaining the relation between the temperature compensation value and the ambient temperature based on the distances between the first identification mark and the second identification mark at a plurality of ambient temperatures.
2. The ambient temperature compensation method of claim 1, further comprising: and moving the platform, adjusting the calibration scale to the focal plane of the camera, and then keeping the distance between the camera and the calibration scale along the optical axis direction of the camera.
3. The ambient temperature compensation method of claim 2, wherein the step S101 comprises:
moving the first identifying mark into the field of view of the camera at the ambient temperature;
acquiring an image of the first identification mark, and obtaining a first distance between the first identification mark and the center of the camera view;
and when the first distance is greater than a preset deviation value, moving the platform until the first distance is less than the preset deviation value, and recording the position of the platform at the moment as the first position.
4. The ambient temperature compensation method of claim 2, wherein the step S102 comprises:
moving the second identifying indicia into the field of view of the camera;
acquiring an image of the second identification mark, and obtaining a second distance between the second identification mark and the center of the camera view;
and when the second distance is greater than the preset deviation value, moving the platform until the second distance is less than the preset deviation value, and recording the position of the platform at the moment as the second position.
5. The ambient temperature compensation method of claim 3 or 4, wherein the distance is a Euclidean distance.
6. The ambient temperature compensation method of claim 2, wherein the step S104 comprises: changing the ambient temperature, and determining the distance between the first identification mark and the second identification mark at different ambient temperatures by repeating the steps S101, S102 and S103.
7. The ambient temperature compensation method of claim 2, wherein the step S104 comprises:
changing the ambient temperature, moving the platform to the first position, and recording a first offset value of the center of the first identification mark and the center of the camera view;
moving the platform to the second position, and recording a second offset value of the center of the second identification mark and the center of the camera view;
calculating distances of the first identifying mark and the second identifying mark at a plurality of ambient temperatures based on the first position, the first offset value, the second position, and the second offset value.
8. The ambient temperature compensation method of claim 6 or 7, wherein the step S105 comprises:
selecting one environmental temperature from the plurality of environmental temperatures as a reference environmental temperature, and taking the distance between the first identification mark and the second identification mark at the environmental temperature as a reference distance;
and calculating temperature compensation values at different environmental temperatures based on the reference distance and the distances between the first identification mark and the second identification mark at different environmental temperatures.
9. The ambient temperature compensation method of claim 8, wherein the step S105 comprises: and obtaining the relation between the temperature compensation value and the ambient temperature through a least square method based on the ambient temperature and the temperature compensation value.
10. The ambient temperature compensation method of any of claims 1-4, wherein the alignment device is a direct imaging lithography device for manufacturing a PCB substrate, the ambient temperature compensation method further comprising:
s106: measuring an exposure chamber temperature of the direct imaging lithography apparatus;
s107: obtaining a temperature compensation value corresponding to the temperature of the exposure chamber according to the temperature of the exposure chamber based on the relation between the temperature compensation value and the ambient temperature;
s108: and performing compensation transformation on the PCB drawing based on the temperature compensation value.
11. The ambient temperature compensation method of claim 1, wherein the two identification marks are identical in shape, size, and color.
12. An alignment device, comprising:
a platform;
the calibration ruler is fixed on the platform;
a camera disposed above the platform and configured to capture an image of the calibrated scale;
a control unit in communication with the platform and the camera and configured to perform the ambient temperature compensation method of any of claims 1-11.
13. The alignment apparatus of claim 12, further comprising an exposure chamber, the control unit in communication with the exposure chamber and further configured to adjust or read an ambient temperature of the exposure chamber.
14. A direct imaging lithographic apparatus comprising the alignment device of claim 12 or 13, configured to: and performing compensation transformation on the PCB drawing based on the temperature compensation value corresponding to the real-time environment temperature, and printing the PCB drawing on the PCB substrate.
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| CN117192908A (en) * | 2023-08-22 | 2023-12-08 | 安徽国芯智能装备有限公司 | Compensation method for expansion and contraction consistency of direct-writing type photoetching machine |
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| CN115628685A (en) * | 2022-08-15 | 2023-01-20 | 魅杰光电科技(上海)有限公司 | Method and equipment for measuring critical dimension and method for positioning critical dimension in grading manner |
| CN115628685B (en) * | 2022-08-15 | 2024-03-26 | 魅杰光电科技(上海)有限公司 | Method and equipment for measuring critical dimension and method for classifying and positioning critical dimension |
| CN117192908A (en) * | 2023-08-22 | 2023-12-08 | 安徽国芯智能装备有限公司 | Compensation method for expansion and contraction consistency of direct-writing type photoetching machine |
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