JP2004330690A - Mask superimposed equipping method of screen printing machine and screen printing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent surely shear in printing by doubly equipping a mask and a substrate in a more accurately positioned state. <P>SOLUTION: The mask 7 having a printing opening part and a substrate supporting unit 3 for holding the substrate W being a material to be, in a transferable manner, printed to the mask 7 are provided, and the substrate W and the mask 7 are doubly provided by operation of the substrate supporting unit 3 to carry out printing. Prior to the doubly equipment of the mask 9 and the substrate W, a circuit pattern of the substrate W and the printing opening part of the mask 7 corresponding to the pattern are imaged to obtain a shear (a positional error) between the circuit pattern and the printing opening part based on those image data. The mask 7 and the substrate W are superimposed by driving and controlling the substrate supporting unit 3 based on this shear. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a mask mounting method for a screen printing apparatus for applying paste such as cream solder on a substrate using a screen mask, and a screen printing apparatus.
[0002]
[Prior art]
Conventionally, a screen mask (hereinafter, referred to as a mask) is overlaid on a substrate set on a stage, and paste such as cream solder, conductive paste, or resistive paste supplied on the mask is expanded with a squeegee. A screen printing apparatus that applies (prints) a paste to a predetermined position on a substrate via a formed opening is generally known (for example, Patent Document 1).
[0003]
In this type of screen printing apparatus, a fiducial mark (hereinafter simply referred to as a mark) marked on each of a mask and a substrate is image-recognized, and based on the recognition result, the mask and the substrate are overlapped while being positioned with respect to each other. ing.
[0004]
[Patent Document 1]
JP 2001-38875 A
[0005]
[Problems to be solved by the invention]
In the above-mentioned conventional apparatus, both are positioned on the basis of the marks marked on the mask and the substrate based on the image recognition of the marks, however, it is assumed that the marks are correctly marked on the mask and the substrate. It is assumed that. That is, when the positional relationship between the mark and the circuit pattern has a displacement (position error) or when the positional relationship between the mark and the printing opening has a displacement (position error) due to deformation such as extension of the mask. However, even if the mask and the substrate are positioned relative to each other with the mark as a reference and the two are overlaid, it is difficult to accurately associate the corresponding circuit pattern with the printing opening.
[0006]
Therefore, it is desired that the mask and the substrate can be overlapped in a state where the circuit pattern and the printing opening are accurately associated even when a printing shift or the like occurs in the mark itself of the substrate. .
[0007]
The present invention has been made in view of the above problems, and has as its object to surely prevent printing misalignment by overlapping a mask and a substrate while positioning them more accurately.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a method for overlaying a mask on a screen printing apparatus according to the present invention includes a mask having a printing opening, a holding unit for holding a substrate which is a printing target, and a mask and a holding unit. A driving means for relatively moving the mask, the mask and the substrate held by the holding means being operated by the operation of the driving means, and the mask and the substrate are overlapped. Prior to the mounting of the mask and the substrate, the circuit pattern of the substrate and the printing opening of the mask corresponding to the circuit pattern are imaged, and the circuit pattern and the printing pattern are printed based on the image data. The position error of the image with respect to the opening is obtained, and the driving means is controlled based on the error, whereby the mask and the substrate are overlaid.
[0009]
According to this method, the relative positional relationship between the substrate and the mask is corrected based on the displacement (positional error) between the circuit pattern and the printing opening, so that the circuit pattern and the printing opening are accurately positioned. The mask and the substrate can be overlapped. In addition, since the position error between the substrate and the mask is obtained based on the image recognition of the substrate and the like, and the driving means is controlled based on this error, the work of mounting the mask and the substrate with the above-described positioning can be performed. It can be automated.
[0010]
In order to obtain the accurate position error between the substrate and the mask, it is effective to image a wide area such as the substrate at one time and obtain the above position errors at a plurality of locations separated from each other. In many cases, the imaging range is limited due to the configuration of the apparatus. Therefore, in the above-described method, the circuit pattern is imaged in a plurality of regions on the substrate as the circuit pattern, and the regions of the mask including the printing openings respectively corresponding to the circuit patterns in these regions are imaged. A position error between the circuit pattern and the corresponding printing opening is obtained, a final position error between the substrate and the mask is obtained based on the position error for each of these areas, and the driving is performed based on the final position error. It is preferred to control the means. According to this method, it is possible to accurately determine a position error in imaging in a narrow range.
[0011]
Further, in the mask overlapping method, a composite image in which a circuit pattern image and an image of a printing opening corresponding to the pattern are generated based on the image data, and the composite image is displayed on a screen. By giving information for moving the circuit pattern or the image of the printing opening and moving the circuit pattern or the image of the printing opening on the display screen, the circuit pattern matches the printing opening on the screen. Then, the position error between the circuit pattern and the printing opening may be obtained based on the difference between the image positions before and after the movement.
[0012]
According to such a method, for example, the operator can visually check the balance between the adjacent print openings and match the print openings with the circuit pattern. Therefore, it is possible to optimally position the substrate and the mask according to the specific degree of deviation, for example, when the circuit pattern and the printing opening are irregularly displaced.
[0013]
On the other hand, a screen printing apparatus according to the present invention includes a mask having a printing opening, holding means for holding a substrate which is a printing target, and driving means for relatively moving the mask and the holding means. In a screen printing apparatus, a first imaging unit capable of imaging a circuit pattern of a substrate held by the holding unit, and an image of a printing opening of the mask corresponding to the circuit pattern imaged by the first imaging unit. A second image pickup means, and image data of the circuit pattern imaged by the first image pickup means and image data of the print opening imaged by the second image pickup means, and the circuit pattern and the print opening are synthesized. A synthetic image generating means for generating image data in a state in which the image data is superimposed, and a display means for displaying an image based on the image data generated by the synthetic image generating means. Image position changing means for changing and displaying a circuit pattern or an image position of a printing opening on a screen in accordance with input information from the input means; and a circuit pattern or printing opening based on image data generated by the composite image generating means. Error calculating means for calculating a position error between the substrate and the mask based on a difference between the image position of the image and the image position after the image position has been changed by the image position changing means, and the driving based on the error obtained by the error calculating means. Control means for controlling the means to overlap the mask and the substrate.
[0014]
According to this screen printing apparatus, an image in a state where the corresponding circuit pattern and the printing opening are overlapped is displayed by the display means. On the other hand, the operator visually checks the deviation between the circuit pattern and the printing opening, and if there is a deviation between the circuit pattern and the printing opening, operates the input means to operate the circuit pattern or the printing opening. Is moved on the screen (by changing the image position), the difference between the image positions before and after the movement is obtained as the position error between the substrate and the mask. Then, as a result of controlling the driving means on the basis of this error, the substrate and the mask are overlaid in a state where the deviation from the circuit pattern or the printing opening is eliminated. Therefore, the mask and the substrate can be overlapped with the circuit pattern and the printing opening accurately aligned.
[0015]
Another screen printing apparatus according to the present invention includes a mask having a printing opening, holding means for holding a substrate which is a printing object, and driving means for relatively moving the mask and the holding means. A screen printing apparatus provided with: a first imaging unit capable of imaging a circuit pattern of a substrate held by the holding unit; and a printing opening of the mask corresponding to the circuit pattern imaged by the first imaging unit. A second imaging unit capable of imaging, the circuit pattern and the printing opening based on image data of the circuit pattern imaged by the first imaging unit and image data of the printing opening imaged by the second imaging unit; Error calculating means for obtaining a position error between the mask and the substrate, and controlling the driving means based on the error obtained by the error calculating means to overlap the mask and the substrate. In which and a control means for.
[0016]
According to this screen printing apparatus, a deviation (position error) between the circuit pattern and the printing opening is obtained by the error calculating means based on the corresponding circuit pattern and each image data of the printing opening, and the driving based on this error is performed. Means are controlled. Therefore, the mask and the substrate can be overlapped with the circuit pattern and the printing opening accurately aligned. In particular, according to this apparatus, since the position error between the mask and the substrate is automatically determined based on image data such as a circuit pattern, it is possible to completely automate a series of mounting operations of the mask and the substrate.
[0017]
In each of the above-described screen devices, the screen device further includes storage means for updatingly storing data relating to the error obtained by the error calculation means, and wherein the control means performs the processing based on the error data stored in the storage means. More preferably, it is configured to control the driving means.
[0018]
That is, for example, the above-described position error may be obtained for each substrate. However, for example, in the case of deformation of a mask or the like, the above-described position error has a substantially common value for each substrate. Therefore, in such a case, the position error is obtained only for a specific substrate, for example, only the first substrate of a production lot, and the position error is stored in the storage means. Thereafter, the stored error data is used. By performing the positioning between the mask and the substrate, it is possible to prevent printing misalignment while efficiently performing the printing process.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 shows an embodiment of a screen printing machine according to the present invention. The screen printing machine includes a printing press main body 2 having a base 1, a substrate support unit 3 for supporting the substrate W in a clamped state, and a conveyor (not shown) for transporting the substrate W to the substrate support unit 3. It has.
[0021]
Although not shown in detail, the substrate support unit 3 includes an RZ stage 3A that supports the substrate W so as to be able to move up and down (movement in the Z-axis direction) and rotate (rotation about the Z-axis), and an RZ stage. The XY stage 3B movably supports the substrate 3A in a substrate transport direction (X-axis direction; a direction orthogonal to the plane of FIG. 1) and a direction orthogonal to the direction (Y-axis direction). The substrate W is moved by the mutual operation of the stages 3A and 3B. That is, in this embodiment, the holding means and the driving means of the present invention are constituted by the substrate supporting unit 3.
[0022]
The RZ stage 3A is equipped with a mask recognition camera 24 (second imaging means) for recognizing the metal mask 7 described below from below, and a lighting device (not shown). The mask recognition camera 24 includes an image sensor such as a CCD area sensor, and a fiducial mark (hereinafter, simply referred to as a mark) printed on the lower surface of the metal mask 7 and a printing mark formed on the metal mask 7. It is configured to be able to image the opening.
[0023]
The printing press main body 2 is provided with a U-shaped frame 2b in a plan view having an open front side (the left side in FIG. 1), and the frame 2b is supported by columns 2a erected at four corners of the base 1. Have been. A metal mask 7 (mask sheet; hereinafter abbreviated as mask 7) having a printing opening is fixed to the frame 2b, and a squeegee unit 5 is disposed above the mask 7. The mask 7 is held on its entire circumference by a frame member 8, and is fixed to the frame 2 b via the frame member 8.
[0024]
The squeegee unit 5 is mounted on a pair of rail members 5a in the Y-axis direction fixed on frames 2b on both left and right sides (on both sides in a direction perpendicular to the paper surface in FIG. 1) in the Y-axis direction, and mounted on the rail members 5a. A beam member 5b which moves along the rail member 5a by operation of a driving means (not shown), a solder supply device (not shown) for supplying cream solder on the mask 7, and a cream solder is expanded on the mask 7 A pair of squeegees 22 and a lifting means 10 for respectively driving the squeegees 22 to move up and down. As described later, the squeegees 22 and 22 are reciprocated in the Y-axis direction during printing, as described later. The squeegees 22 are alternately slid along the surface of the mask 7 to expand the solder cream on the mask 7. That.
[0025]
Also, on the side (right side in FIG. 1) of the squeegee unit 5 in the printing press main body 2, a board recognition camera 25 (first imaging unit) for recognizing the board W supported by the board support unit 3 from above. ) And its lighting device (not shown). The board recognition camera 25 includes an image pickup device such as a CCD area sensor, and picks up an image of a fiducial mark (hereinafter, simply referred to as a mark) marked on the upper surface of the board W and a circuit pattern formed on the board W. It is configured to be able to.
[0026]
The RZ stage 3A of the substrate support unit 3 is moved to the position corresponding to the squeegee unit 5 by the operation of the XY stage 3B (solid line position in FIG. 1; referred to as a work position) and from the work position in the X-axis direction. The position of the RZ stage 3A when the RZ stage 3A is placed at this imaging position is configured so as to be movable to a position (the dashed-dotted line position in FIG. 1; imaging position). It is arranged so that the substrate W supported by can be recognized.
[0027]
FIG. 2 is a block diagram illustrating a control system of the screen printing apparatus. As shown in FIG. 1, the screen printing apparatus includes a well-known CPU that executes a logical operation, a ROM that previously stores various programs for controlling the CPU, a RAM that temporarily stores various data during operation of the apparatus, and the like. , The controllers 26 to 27 of the squeegee unit 5, the substrate support unit 3 (the RZ stage 3A, the XY stage 3B), the mask recognition camera 24, and the substrate recognition camera. 25 and the like are all connected to the control device 30.
[0028]
The control device 30 includes a main control unit 31, an image processing unit 32, an error calculation unit 33, an error storage unit 34, and the like as its functional configuration.
[0029]
The main control unit 31 controls the overall operation of the screen printing apparatus, and controls the drive of the squeegee unit 5 and the like via the controllers 26 to 28 so as to execute a predetermined printing operation according to a program stored in advance. Is what you do. In particular, before the printing process is performed on the first substrate W in the production lot, the drive control of the substrate support unit 3 and the like is performed to execute a preparation process for acquiring data for positioning the substrate W and the mask 7. I do.
[0030]
The image processing means 32 performs a predetermined process on the image data captured by the mask recognition camera 24 and the board recognition camera 25. Based on this, a composite image of the mask 7 (printing opening) and the substrate W (circuit pattern), that is, a virtual image (initial image data) in which the mask 7 and the substrate W are superimposed on the basis of the mark is created and described later. An image (updated image data) in which the composite image is changed is generated according to the vector information input by the operation of the input unit 36. Specifically, based on the vector information, an image in a state where the image of the substrate W is moved with respect to the image of the mask 7 (a state where the image position is changed) is generated. Note that such image processing can be performed based on a conventionally known image processing technique of changing (switching) an image display position in accordance with externally input information. In the present embodiment, the image processing is stored in advance. This is executed by the image processing device 32 controlling the main control unit 31 according to a program. That is, in this embodiment, the main control unit 31 and the image processing device 32 constitute a combined image generating unit and an image position changing unit of the present invention.
[0031]
The error calculator 33 calculates the displacement of the image of the substrate W based on the initial image data generated by the image processor 32 and the final updated image data obtained by moving the image of the substrate W with respect to the image of the mask 7. Calculate the quantity.
[0032]
The error storage means 34 stores the displacement calculated by the error calculation means 33 as a deviation (position error) between the mask 7 and the substrate W. The error calculated by the error calculation means 33 is updated and stored. I do.
[0033]
The control device 30 is further connected to display means 35 such as a CRT and input means 36 such as a keyboard.
[0034]
The display means 35 displays information and the like regarding various operation states during the printing operation to the operator, and displays a composite image of the mask 7 and the substrate W based on the image data generated by the image processing means 32 during the preparation processing. .
[0035]
The input means 36 is for inputting various kinds of information to the control device 30. During the preparation processing, input of vector information for moving the image of the substrate W displayed on the display means 35 is performed through the input means 36. Done.
[0036]
Next, an example of a printing operation based on the control of the control device 30 will be described based on the flowchart of FIG.
[0037]
When the printing operation is started, first, the substrate supporting unit 3 is set at an initial position where the substrate W can be received, and after the initial value “1” is set as the counter value, the substrate W is transferred from the conveyor to the substrate supporting unit. It is loaded onto the unit 3 and clamped (steps S1 and S2).
[0038]
Next, the substrate W is placed at an image capturing position by the substrate recognition camera 25 by the operation of the substrate support unit 3 (the RZ stage 3A, the XY stage 3B), and the mark is printed on the substrate W by the substrate recognition camera 25. Is imaged, recognition (position recognition) of the substrate W is performed based on the mark (step S3).
[0039]
Then, it is determined whether the counter value is “1”, that is, whether the substrate W is the first substrate W in the production lot (step S4). If it is determined that the counter value is "1", the process proceeds to step S5, and a preparation process for acquiring positioning data is performed in steps S5 to S12.
[0040]
In this preparation process, first, the circuit pattern of a plurality of regions on the substrate W predetermined based on the mark is captured by the substrate recognition camera 25 by moving the substrate support unit 3 (step S5). In the present embodiment, two circuit patterns on the substrate W that are separated in the diagonal direction are sequentially imaged by the substrate recognition camera 25.
[0041]
When the substrate recognition camera 25 finishes capturing the image of the substrate W, the substrate support unit 3 is placed at the working position, and the mark to be marked on the mask 7 is captured by the mask recognition camera 24. (Position recognition) is performed (step S6).
[0042]
Next, as the substrate support unit 3 moves, two areas including the printing opening corresponding to the circuit pattern imaged in step S5 are sequentially imaged by the mask recognition camera 24 (step S7). At this time, the driving of the substrate support unit 3 (XY stage 3B) is controlled based on the position of the mask 7 recognized in step S6.
[0043]
Then, based on the image data of the substrate W and the mask 7 acquired in Steps S5 and S7, a virtual image (composite image) in a state of being superimposed on the basis of each mark of the mask 7 and the substrate W is generated by the image processing means 32. The created virtual image is displayed by the display means 35, and a display requesting “correction processing” is also displayed. For example, in the present embodiment, as shown in FIG. 4 (upper diagram), the two composite images (images 40A and 40B) are respectively displayed on the screen of the display unit 35 (steps S8 and S9). ). It should be noted that the display requesting the “correction processing” is omitted in FIG.
[0044]
Here, the “correction process” refers to a process of correcting a shift between the mask 7 and the substrate W on a screen by an operation of an operator. That is, since the composite image displayed on the screen is an image in which the printing opening and the circuit pattern are superimposed on the basis of each mark of the mask 7 and the substrate W as described above, the mark on the substrate W and the circuit pattern If both the positional relationship of the mask 7 and the positional relationship between the mark of the mask 7 and the printing opening are within an appropriate range, an image in which the printing opening and the circuit pattern completely correspond (overlap) as a composite image. Will be displayed. However, if there is a deviation in the positional relationship between the mark on the substrate W and the circuit pattern due to, for example, a printing error of the mark, the image 7a of the printing opening and the image of the circuit pattern are displayed on the composite image as shown in FIG. Wa will be displayed in a state shifted from Wa. The above-described “correction processing” is processing for virtually correcting such a shift by operating the input unit 36 to move the image of the substrate W. Specifically, the operator inputs vector information, that is, the direction and amount (size) of moving the substrate W, for each of the images 40A and 40B, and updates the image in accordance with the input (redisplay based on the updated image data). This is performed by matching the image 7a of the printing opening and the image Wa of the circuit pattern on the screen while confirming (1). In this case, the input operation and the image confirmation are repeated as necessary.
[0045]
In step S10, it is determined whether or not the correction processing has been completed. If it is determined that the correction processing has been completed, the error calculating means 33 calculates an error between the substrate W and the mask 7 (step S11). The calculation result is updated and stored in the error storage means 34 (step S12). For example, after the correction processing, if the operator operates the input means 36 to input that the correction processing work has been completed, “YES” is determined in the step S10.
[0046]
In step S11, as shown in FIG. 4 (lower view), the amount of change in the XY direction of the center of the image of the substrate W in the image 40a (O ₁ → O ₁ ′) And the amount of change in the XY direction (O ₂ → O ₂ ') Is obtained as an error in the X-Y axis direction of the substrate W and the mask 7, and a line segment (O) connecting the image center of the uncorrected substrate W in each of the images 40a and 40b. ₁ -O ₂ ) And the line segment (O) connecting the corrected image center of the substrate W ₁ '-O ₂ ) Is determined as an error in the R-axis direction between the substrate W and the mask 7.
[0047]
When the preparation process of steps S5 to S12 is completed, the substrate support unit 3 moves to the work position to position the substrate W in the X, Y, and R axis directions with respect to the mask 7, and then moves the RZ stage 3A. The substrate W is lifted by the operation, whereby the substrate W is loaded on the mask 7 from below (step S13). The positioning of the substrate W is performed based on the error data stored in the error storage unit 34 after the basic positioning of the substrate W with respect to the mask 7 is performed based on the mark images acquired in steps S3 and S6. This is performed by correcting the position of W. Note that the basic positioning operation and the position correction may be performed simultaneously.
[0048]
After the substrate W is overlaid on the mask 7, the squeegee unit 5 is operated, whereby the printing process is started (step S14). Specifically, after the squeegees 22 and 22 are arranged at a predetermined work start position, the squeegees 22 and 22 (one side squeegee 22) are moved to a predetermined height position, that is, the tip (lower end) by the operation of the lifting / lowering means 10. ) Is set at a height position in contact with the mask 7. Then, after the cream solder is supplied onto the mask 7 by the solder supply device, the squeegees 22 and 22 alternately slide along the surface of the mask 7 while reciprocating in the Y-axis direction. 7 is applied to the substrate W through the printing opening 7.
[0049]
Then, it is determined whether or not the printing process has been completed in step S15. If it is determined that the printing process has been completed, the squeegees 22 and 22 are reset to the rising end position, and the substrate supporting unit 3 is returned to the initial position. After reset, the substrate W is unloaded (step S16).
[0050]
When the substrates W are unloaded, it is determined whether or not the processing of the predetermined number N of substrates W has been completed (step S17). If it is determined that the processing has not been completed, the counter value is incremented. After that (step S18), the process proceeds to step S2, where the next substrate W is carried into the substrate support unit 3.
[0051]
If it is determined in step S4 that the counter value is not "1", that is, if the substrate W is not the first substrate W in the production lot, the processing in steps S5 to S12 is skipped, and the mark recognition processing in step S19 is skipped. After that, the process moves to step S13. That is, if NO is determined in step S4, the substrate W is reset to the working position by the operation of the substrate support unit 3, and the mark marked on the mask 7 is imaged by the mask recognition camera 24 mounted on the substrate support unit 3. Is performed (step S19). Then, after the basic positioning of the substrate W with respect to the mask 7 is performed based on the mark images acquired in steps S3 and S19, the position of the substrate W is determined based on the error data stored in the error storage unit 34. The correction is performed, and the substrate W is mounted on the mask 7 in this state.
[0052]
In this way, when it is finally determined in step S17 that the processing of the predetermined number N of substrates W has been completed, this flowchart ends.
[0053]
As described above, in this screen printing apparatus, a specific shift (position error) between the circuit pattern and the printing opening when the substrate W and the mask 7 are positioned relative to each other with reference to the mark is obtained in advance (preparation). Processing: Steps S5 to S12 in FIG. 3), at the time of printing processing, the substrate W and the mask 7 are positioned based on the fiducial mark, and based on the error obtained in the above-described preparation processing. Since the position is corrected, if there is an error in the positional relationship between the mark and the circuit pattern due to, for example, a printing error of the mark, or the positional relationship between the mark and the printing opening due to deformation such as extension of the mask itself. Even when an error occurs, the substrate W and the mask 7 can be overlaid in a state where the corresponding circuit pattern and the printing opening surely correspond to each other. Therefore, compared with the conventional screen printing apparatus in which the substrate and the mask are positioned relative to each other based only on the image recognition of the mark, it is possible to more accurately overlap the substrate W and the mask 7, and as a result, the printing misalignment is caused. There is an effect that the occurrence of the occurrence can be more reliably prevented.
[0054]
In particular, in the above-described preparation operation, a virtual image in which the image of the circuit pattern and the image of the printing opening are superimposed on the screen based on the mark is displayed on the screen, and the operator operates the input means 36 while looking at the screen to operate the circuit pattern image. By moving Wa on the screen, the above-described error is obtained from the displacement amount or the like, so that a highly reliable value based on the visual judgment of the operator can be obtained as the value of the error. In other words, even in the case where unevenness of the printing opening is caused by the deformation of the mask 7, according to the visual judgment of the operator, the balance with the adjacent printing opening is considered. The printing opening and the circuit pattern can be aligned. Therefore, there is an effect that mutual positional correction when the substrate W is mounted on the mask 7 can be accurately performed in accordance with a specific state of displacement.
[0055]
Further, in this screen printing apparatus, error data is stored by executing a preparation process prior to the first printing process of a production lot, and for a substrate W belonging to a common production lot, based on the stored error data. Since the position correction between the mask 7 and the substrate W is performed, there is also an effect that the printing process can proceed rationally. That is, it is conceivable to execute the preparation process for each substrate of the production lot, but in this case, it takes time to perform the printing process per substrate. On the other hand, when an error occurs in the positional relationship between the mark and the printing opening due to the deformation of the mask 7, the above-described error has a value common to each substrate W. In general, a mark printing error on the substrate W often occurs in units of production lots. In this case, in a common production lot, the error tends to be a common value for each substrate W. Therefore, by performing the preparation process only once before the printing process of the production lot and storing the error in an updated manner as described above, it is possible to prevent the printing displacement of each substrate W, The printing process can be performed on each substrate in the same time as that described above, and as a result, both quality and productivity can be achieved.
[0056]
The screen printing apparatus described above is an embodiment of the screen printing apparatus according to the present invention, and the specific configuration can be appropriately changed without departing from the gist of the present invention. For example, the following embodiments can be adopted.
{Circle around (1)} When the basic positional relationship between the substrate W and the mask 7 can be ascertained by another method, the processing of steps S3 and S6 in FIG. 3 can be omitted.
{Circle around (2)} In the embodiment, the circuit pattern in a plurality of regions on the substrate W is imaged by the substrate recognition camera 25, and the plurality of regions of the mask 7 corresponding to the region are imaged by the mask recognition camera 24. The number of regions to be imaged may be one. In this case, in the process of step S11 in FIG. 3 (error calculation process), an error between the substrate W and the mask 7 may be obtained based on the amount of change in a plurality of coordinate positions in the image of the substrate W. Good.
{Circle around (3)} In the embodiment, the operator operates the input unit 36 to move the displayed image of the substrate W on the display screen, so that the error calculation unit 33 calculates the position error. An arrangement may be made wherein the error is calculated directly from the composite image data without performing such an operation by the operator.
{Circle around (4)} In the embodiment, the error data is obtained only once for each production lot by executing a preparation process (the processes of steps S5 to S12 in FIG. 3) before printing the first substrate W of the production lot. However, it goes without saying that the preparation process may be executed a plurality of times during the production lot, and the error data may be updated one or more times during the production lot.
[0057]
【The invention's effect】
As described above, according to the present invention, the shift (position error) between the circuit pattern of the substrate and the printing opening of the mask corresponding to the pattern is image-recognized, and the relative position between the substrate and the mask is determined based on the shift. Since the substrate and the mask are overlapped after correcting the positional relationship, the mask and the substrate can be overlapped with the corresponding circuit pattern and the printing opening accurately aligned. Therefore, compared with the conventional method of positioning and overlaying the substrate and the mask based only on the image recognition of the fiducial mark, the overlaying of the substrate and the mask can be performed more accurately, and as a result, the printing can be performed. Deviation can be more reliably prevented.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing a screen printing apparatus according to the present invention.
FIG. 2 is a block diagram illustrating a control system of the screen printing apparatus.
FIG. 3 is a flowchart illustrating an example of a printing operation based on control by the control system.
FIG. 4 is a schematic diagram for explaining a display state of a composite image and a method of calculating a correction value.
[Explanation of symbols]
3 Substrate support unit
3A R-Z stage
3B XY stage
5 Squeegee unit
7 Metal mask
7a Image of printing opening
22 Squeegee
30 Control device
31 Main control means
32 Image processing means
33 Error calculation means
34 Error storage means
W substrate
Wa Circuit pattern image

Claims (6)

A mask having an opening for printing; holding means for holding a substrate as a printing object; and driving means for relatively moving the mask and the holding means, and holding the holding means by the operation of the driving means. A method of overlaying the mask and the substrate of the screen printing apparatus for printing by overlaying the substrate and the mask,
Prior to the mounting of the mask and the substrate, the circuit pattern of the substrate and the printing opening of the mask corresponding to the circuit pattern are imaged, and the circuit pattern and the printing opening are printed based on the image data. A position error of the image of the screen printing apparatus, and controlling the driving means based on the error to overlap the mask and the substrate. A mask mounting method for a screen printing apparatus according to claim 1,
As the circuit pattern, the circuit patterns in a plurality of regions on the substrate are imaged, and the mask regions including the printing openings respectively corresponding to the circuit patterns in these regions are imaged. A position error with respect to the opening is obtained, a final position error between the substrate and the mask is obtained based on the position error for each region, and the driving unit is controlled based on the final position error. A method for mounting a mask on a screen printing apparatus. In the mask mounting method of the screen printing apparatus according to claim 1 or 2,
Based on the image data, generate a composite image in which a circuit pattern image and a print opening image corresponding to the pattern are superimposed, display the composite image on the screen, and move the circuit pattern or the image of the print opening. By giving information for causing the circuit pattern or the image of the printing opening to move on the display screen, the circuit pattern matches the printing opening on the screen, and the difference between the image positions before and after the movement is determined. A mask overlapping method for a screen printing apparatus, wherein a position error between a circuit pattern and a printing opening is calculated based on the position error. In a screen printing apparatus including a mask having a printing opening, a holding unit that holds a substrate that is a print target, and a driving unit that relatively moves the mask and the holding unit,
A first imaging unit capable of imaging a circuit pattern of a substrate held by the holding unit; and a second imaging unit capable of imaging a printing opening of the mask corresponding to the circuit pattern imaged by the first imaging unit. When,
The image data of the circuit pattern imaged by the first image pickup means and the image data of the print opening imaged by the second image pickup means are combined and the circuit pattern and the print opening are superimposed. Composite image generating means for generating image data, display means for displaying an image based on the image data generated by the composite image generating means,
Input means for inputting information for moving the circuit pattern or the image of the printing opening among the images displayed on the display means,
Image position changing means for changing and displaying the image position of the circuit pattern or the printing opening on the screen according to the input information by the input means,
A position error between a substrate and a mask is determined based on a difference between an image position of a circuit pattern or a printing opening based on image data generated by the composite image generation unit and the image position after being changed by the image position change unit. Error calculating means to be obtained;
A screen printing apparatus, comprising: control means for controlling the driving means based on the error calculated by the error calculation means to overlap the mask and the substrate. In a screen printing apparatus including a mask having a printing opening, a holding unit that holds a substrate that is a print target, and a driving unit that relatively moves the mask and the holding unit,
A first imaging unit capable of imaging a circuit pattern of the substrate serving as the holding unit;
A second imaging unit capable of imaging a printing opening of the mask corresponding to the circuit pattern imaged by the first imaging unit;
Error calculation for obtaining a position error between the circuit pattern and the printing opening based on image data of the circuit pattern imaged by the first imaging means and image data of the printing opening imaged by the second imaging means. Means,
A screen printing apparatus, comprising: control means for controlling the driving means based on the error calculated by the error calculation means to overlap the mask and the substrate. The screen printing device according to claim 4 or 5,
A storage unit that stores data relating to the error obtained by the error calculation unit in an updated manner, wherein the control unit controls the driving unit based on the error data stored in the storage unit. Screen printing device.

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