JP4806581B2 - Light amount adjusting method, image recording method and apparatus - Google Patents

Description

  The present invention controls an exposure head having an independent light source that outputs a light beam and arranged along an image recording medium according to image data, and adjusts the amount of light when recording an image on the image recording medium. The present invention relates to a method, an image recording method, and an apparatus.

  FIG. 27 is an explanatory diagram of the manufacturing process of the printed wiring board. A substrate 2 having a copper foil 1 deposited thereon by vapor deposition or the like is prepared, and a photoresist 3 made of a photosensitive material is thermocompression-bonded (laminated) on the copper foil 1. Next, after the photoresist 3 is exposed in accordance with the wiring pattern by the exposure device, the photoresist 3 is developed with a developer and the unexposed photoresist 3 is removed. The copper foil 1 exposed by removing the photoresist 3 is etched with an etchant, and then the remaining photoresist 3 is stripped with a stripper. As a result, a printed wiring board in which the copper foil 1 having a desired wiring pattern remains on the substrate 2 is manufactured.

  Here, as an apparatus capable of exposing and recording a wiring pattern on the photoresist 3, an image recording apparatus is known in which light beams output from a plurality of light sources are modulated in accordance with image data and guided to a photosensitive material. . In such an image recording apparatus, if the amount of light beam output from each light source is different, the image recorded on the photosensitive material will be uneven. Therefore, the light beam amount for each light source using a light receiving element. Detect and adjust.

  However, since the light receiving elements generally have different sensitivities to the wavelength of light received, if the wavelength of the light beam output from each light source is different, the detection value of the light amount also differs, and correct adjustment cannot be performed. End up. Therefore, there is one in which the light amount of the light beam output from the light source is corrected and detected according to the wavelength (see Patent Document 1).

Japanese Patent Publication No. 7-117447

  By the way, in general, since the photosensitive material itself on which an image is recorded also has different sensitivity to the wavelength of the irradiated light beam, even if the light quantity of each light beam is adjusted in consideration of the wavelength dependency of the light receiving element, There is no guarantee that a consistent image can be recorded. Further, if the beam diameter, the focus state by the optical system, and the like are different for each light beam, even if the image is exposed with the same light amount, the recorded image is uneven.

  An object of the present invention is to provide a light amount adjustment method, an image recording method, and an apparatus capable of recording a desired image without unevenness on an image recording medium with high accuracy using a plurality of light sources.

  Another object of the present invention is to provide a light amount adjusting method, an image recording method and an apparatus capable of correcting a local amount of a light beam output from each light source and recording a desired image with high accuracy. To do.

  It is another object of the present invention to provide a light amount adjustment method, an image recording method and an apparatus capable of correcting a non-uniformity caused by processing of an image recording medium and recording a desired image with high accuracy.

  Still another object of the present invention is to provide a light amount adjustment method, an image recording method and an apparatus capable of correcting a non-uniformity caused by sensitivity characteristics of an image recording medium and recording a desired image with high accuracy. .

The image recording method of the present invention controls a plurality of exposure heads having a light source that outputs a light beam and arranged along an image recording medium according to image data, and records an image on the image recording medium. In the method
Obtaining the beam diameter of each light beam guided from each exposure head to the image recording medium for each exposure head;
Based on the relationship of the recording state of the image recorded on the image recording medium with respect to the beam diameter of the light beam, each light beam is adjusted to adjust the recording state of the image recorded on the image recording medium by each exposure head. Correcting the amount of light,
Controlling each of the exposure heads according to the image data, and recording an image on the image recording medium using the light beams whose light amounts have been corrected;
It is characterized by comprising.

The light amount adjusting method of the present invention controls a plurality of exposure heads having a light source that outputs a light beam and arranged along an image recording medium according to image data, and records an image on the image recording medium.
Obtaining the beam diameter of each light beam guided from each exposure head to the image recording medium for each exposure head;
Based on the relationship of the recording state of the image recorded on the image recording medium with respect to the beam diameter of the light beam, each light beam is adjusted to adjust the recording state of the image recorded on the image recording medium by each exposure head. The amount of light is adjusted.

An image recording apparatus of the present invention controls a plurality of exposure heads having a light source that outputs a light beam and arranged along an image recording medium according to image data, and records an image on the image recording medium In the device
Relationship storage means for storing a relationship of a recording state of an image recorded on the image recording medium with respect to a beam diameter of the light beam;
A beam diameter of each light beam guided from each exposure head to the image recording medium is acquired for each exposure head, and the image recorded on the image recording medium by each exposure head is obtained based on the relationship. A light amount correcting means for correcting the light amount of each light beam in order to adjust the recording state;
Exposure head control means for controlling each exposure head according to the image data and recording an image on the image recording medium using each light beam whose light amount has been corrected;
It is characterized by providing.

  In the light amount adjustment method, the image recording method, and the apparatus of the present invention, a test pattern is recorded on an image recording medium by controlling light beams output from a plurality of light sources according to test data, and the image characteristics of the test pattern are constant. As described above, by correcting the light amount of the light beam output from each light source, a desired image without image unevenness can be recorded with high accuracy without being affected by the wavelength of the light beam.

  FIG. 1 shows an exposure apparatus 10 that performs exposure processing of a printed wiring board or the like, which is an embodiment to which the light amount adjustment method, image recording method, and apparatus of the present invention are applied. The exposure apparatus 10 includes a surface plate 14 that is supported by a plurality of legs 12 and is extremely small in deformation. On the surface plate 14, an exposure stage 18 reciprocates in the direction of an arrow via two guide rails 16. Installed as possible. A rectangular substrate F (image recording medium) coated with a photosensitive material is sucked and held on the exposure stage 18.

  A gate-shaped column 20 is installed at the center of the surface plate 14 so as to straddle the guide rail 16. CCD cameras 22a and 22b for detecting the mounting position of the substrate F with respect to the exposure stage 18 are fixed to one side of the column 20, and an image is exposed to the substrate F on the other side of the column 20. A scanner 26 in which a plurality of exposure heads 24a to 24j to be recorded are positioned and held is fixed. The exposure heads 24a to 24j are arranged in a staggered pattern in two rows in a direction orthogonal to the scanning direction of the substrate F (the moving direction of the exposure stage 18). Strobes 64a and 64b are attached to the CCD cameras 22a and 22b via rod lenses 62a and 62b. The strobes 64a and 64b irradiate the imaging areas of the CCD cameras 22a and 22b with illumination light composed of infrared light that does not expose the substrate F.

  Further, a guide table 66 extending in a direction orthogonal to the moving direction of the exposure stage 18 is attached to the end of the surface plate 14, and the guide table 66 is output from the exposure heads 24a to 24j. A photo sensor 68 that detects the amount of light of the laser beam L is arranged to be movable in the direction of the arrow x.

  FIG. 2 shows the configuration of each of the exposure heads 24a to 24j. For example, laser beams L output from independent semiconductor lasers (light sources) constituting the light source units 28 a to 28 j are combined and introduced into the exposure heads 24 a to 24 j through the optical fiber 30. A rod lens 32, a reflection mirror 34, and a digital micromirror device (DMD) 36 are arranged in order at the exit end of the optical fiber 30 into which the laser beam L is introduced.

  As shown in FIG. 3, the DMD 36 (spatial light modulation element) is capable of swinging a large number of micromirrors 40 (spatial light modulation elements) arranged in a lattice pattern on an SRAM cell (memory cell) 38. A material having a high reflectivity such as aluminum is deposited on the surface of each micromirror 40. When a digital signal according to the drawing data is written from the DMD controller 42 to the SRAM cell, each micromirror 40 is tilted in a predetermined direction according to the signal, and the on / off state of the laser beam L is realized according to the tilted state.

  In the emission direction of the laser beam L reflected by the DMD 36 whose on / off state is controlled, a large number of lenses are arranged corresponding to the first imaging optical lenses 44 and 46 that are the magnifying optical system and the micromirrors 40 of the DMD 36. The provided microlens array 48 and second imaging optical lenses 50 and 52 which are zoom optical systems are sequentially arranged. Before and after the micro lens array 48, micro aperture arrays 54 and 56 for removing stray light and adjusting the laser beam L to a predetermined diameter are disposed.

  As shown in FIGS. 4 and 5, the DMD 36 constituting the exposure heads 24 a to 24 j is set in a state inclined at a predetermined angle with respect to the moving direction of the exposure heads 24 a to 24 j in order to achieve high resolution. That is, by inclining the DMD 36 with respect to the scanning direction of the substrate F (arrow y direction), a direction (arrow x direction) orthogonal to the scanning direction of the substrate F with respect to the interval m with respect to the arrangement direction of the micromirrors 40 constituting the DMD ) Can be narrowed and the resolution can be set high.

  In FIG. 5, a plurality of micromirrors 40 are arranged on the same scanning line 57 in the scanning direction (arrow y direction), and the substrate F is guided to substantially the same position by the plurality of micromirrors 40. The image is subjected to multiple exposure by the laser beam L. Thereby, the unevenness of the light quantity between the micromirrors 40 is averaged. In addition, the exposure areas 58a to 58j by the exposure heads 24a to 24j are set so as to overlap in the direction of the arrow x so that there is no joint between the exposure heads 24a to 24j.

  Here, the light amounts Ea (x) to Ej (x) of the laser beams L output from the light source units 28a to 28j and guided to the substrate F from the exposure heads 24a to 24j are, for example, as shown in FIG. In the state before adjustment, the light source units 28a to 28j are different. Further, the light quantity of the laser beam L guided to the substrate F through each micromirror 40 constituting the DMD 36 of each exposure head 24a to 24j is also reflected by the DMD 36 in the direction of the arrow x that is the arrangement direction of the exposure heads 24a to 24j. And locality due to the optical system and the like. In such a state where there is unevenness in the amount of light, as shown in FIG. 7, when the image is exposed and recorded on the substrate F using the laser beam L with a small amount of combined light reflected by the plurality of micromirrors 40, In the case where an image is exposed and recorded on the substrate F using a large number of laser beams L, the threshold W at which the photosensitive material applied to the substrate F is exposed to a predetermined state is set as th, and the width W1 in the arrow x direction of the recorded image , W2 is different. In addition, as shown in FIG. 27, when the exposed substrate F is further subjected to development processing, etching processing, and stripping processing, in addition to the influence of unevenness in the light amount of the laser beam L, resist lamination Unevenness in development, unevenness in etching, unevenness in etching, unevenness in peeling, and the like cause fluctuations in the width of the image.

  Therefore, in the present embodiment, the micromirrors used to correct the light amount of the laser beam L output from each of the light source units 28a to 28j and to form one pixel on the substrate F in consideration of each of the above fluctuation factors. By setting the number of 40 using the mask data, as shown in FIG. 8, the width W1 in the arrow x direction of the image formed in consideration of the final peeling process of the substrate F is constant regardless of the position. Control to be

  FIG. 9 is a control circuit block diagram of the exposure apparatus 10 having a function for performing such control.

  The exposure apparatus 10 includes an image data input unit 70 for inputting image data to be exposed and recorded on the substrate F, a frame memory 72 for storing the input two-dimensional image data, and image data stored in the frame memory 72. A resolution conversion unit 74 that converts the resolution to a high resolution in accordance with the size and arrangement of the micromirrors 40 of the DMD 36 constituting the exposure heads 24a to 24j, and assigns the converted image data to the micromirrors 40 as output data. An output data calculation unit 76; an output data correction unit 78 (second light amount correction unit) that corrects the output data according to mask data; a DMD controller 42 (exposure head control unit) that controls the DMD 36 according to the corrected output data; Using the DMD 36 controlled by the DMD controller 42, the substrate F can be And a exposure head 24a~24j for exposure recording an image.

  The resolution converter 74 is connected to a test data memory 80 (test data storage means) that stores test data. The test data is data for exposing and recording a test pattern having a constant line width and space width on the substrate F and creating mask data based on the test pattern.

  The output data correction unit 78 is connected to a mask data memory 82 that stores mask data. The mask data is data for correcting the locality of the image by each of the exposure heads 24 a to 24 j by designating the micromirror 40 that is always turned off, and is set in the mask data setting unit 86. The exposure apparatus 10 includes a light amount locality data calculation unit 88 that calculates light amount locality data based on the light amount of the laser beam L detected by the photosensor 68. The light amount locality data calculated by the light amount locality data calculating unit 88 is supplied to the mask data setting unit 86.

  The mask data setting unit 86 changes the light amount of the laser beam L with respect to the line width change amount (recording state) and the line width change amount of the test pattern stored in the light amount / line width table memory 87 (recording state / light amount storage means). Mask data is set using a table showing the relationship with the quantity. The light source control unit 89 (light amount correction means) corrects the light amount of the laser beam L output from each of the light source units 28a to 28j using the relationship stored in the light amount / line width table memory 87.

  The exposure apparatus 10 of the present embodiment is basically configured as described above. Next, based on the flowchart shown in FIG. 10, the light amount of the laser beam L is corrected and a desired image is formed on the substrate F. The procedure for exposure recording will be described.

  First, after the exposure stage 18 is moved and the photo sensor 68 is disposed below the exposure heads 24a to 24j, the exposure heads 24a to 24j are driven (step S1). In this case, the DMD controller 42 sets all the micromirrors 40 constituting the DMD 36 to an on state that guides the laser beam L to the photosensor 68.

  The photo sensor 68 measures the light amount of the laser beam L output from the exposure heads 24a to 24j while moving in the arrow x direction shown in FIG. 1, and supplies the light amount to the light amount locality data calculation unit 88 (step S2). The light quantity locality data calculation unit 88 calculates the light quantity locality data of the laser beam L at each position x in the direction of the arrow x based on the light quantity measured by the photosensor 68, and supplies it to the mask data setting unit 86 (step S3). ).

  The mask data setting unit 86 creates initial mask data for making the light amounts Ea (x) to Ej (x) of the laser beam L at each position x of the substrate F constant based on the supplied light amount locality data. Then, it is stored in the mask data memory 82 (step S4). Note that the initial mask data is, for example, among the plurality of micromirrors 40 that form one pixel of the image at each position x of the substrate F so that the locality of the light amounts Ea (x) to Ej (x) shown in FIG. Are set as data for controlling the off state according to the light quantity locality data. In FIG. 5, the micromirror 40 set to the OFF state by the initial mask data is illustrated by a black circle.

  After setting the initial mask data, the exposure stage 18 is moved to place the substrate F under the exposure heads 24a to 24j, and the exposure heads 24a to 24j are driven based on the test data (step S5).

  The resolution conversion unit 74 reads the test data from the test data memory 80, converts the test data to a resolution corresponding to each micromirror 40 constituting the DMD 36, and then supplies the test data to the output data calculation unit 76. The output data calculation unit 76 supplies the test data to the output data correction unit 78 as test output data that is an on / off signal of each micromirror 40. The output data correction unit 78 forcibly turns off the test output data of the micromirror 40 corresponding to the position of the initial mask data supplied from the mask data memory 82 and then outputs the test output data to the DMD controller 42.

  The DMD controller 42 irradiates the substrate F with the laser beam L from the light source units 28a to 28j by performing on / off control of each micromirror 40 constituting the DMD 36 according to the test output data corrected by the initial mask data. The pattern is exposed and recorded (step S6). Since this test pattern is formed according to the test output data corrected by the initial mask data, the pattern in which the influence of the locality of the light amount of the laser beam L irradiated to the substrate F from each of the exposure heads 24a to 24j is eliminated. It becomes. The substrate F on which the test pattern is exposed and recorded is subjected to a development process, an etching process, and a resist peeling process, and the substrate F on which the test pattern remains is generated (step S7). This test pattern is, for example, a large number of rectangular test patterns 90 formed with line widths Wa (x) to Wj (x) at respective positions x in the direction of the arrow x as shown in FIG. In a non-ideal state, rendering is performed based on test output data in which the line widths Wa (x) to Wj (x) and the space width are constant regardless of the position x.

  In this case, since the laser beam L output from each of the light source units 28a to 28j and applied to the substrate F usually has a different wavelength, beam diameter, focus state, etc., the light quantity locality is adjusted by the initial mask data. In addition, the line widths Wa (x) to Wj (x) of the test pattern 90 due to the difference in the photosensitive characteristics depending on the wavelength of the photosensitive material applied to the substrate F and the unevenness due to the position x in the development processing or the like. The space width may not be constant.

  Therefore, the line widths Wa (x) to Wj (x) of the test pattern 90 formed on the substrate F are measured for each of the exposure heads 24a to 24j (step S8). Based on the measurement result, the light source controller 89, as shown in FIG. 12, the minimum values Wmin (a) to Wmin () of the line widths Wa (x) to Wj (x) formed by the exposure heads 24a to 24j. The light amount correction amounts ΔEa to ΔEj for correcting j) to the minimum line width Wmin among the minimum values Wmin (a) to Wmin (j) are calculated for each of the light source units 28a to 28j (step S9).

  FIG. 13 exemplifies relationships M1 and M2 between the light amount change amount ΔE of the laser beam L irradiated to the substrate F and the accompanying line width change amount ΔW. The relationships M1 and M2 correspond to, for example, the type of photosensitive material applied to the substrate F, and are obtained in advance by experiments or the like and stored in the light quantity / line width table memory 87. The light source controller 89 selects the relationship M1 or M2 corresponding to the type of photosensitive material from the light quantity / line width table memory 87, and the minimum values Wmin (a) to Wmin of the line widths Wa (x) to Wj (x). The light amount change amount ΔE that can obtain each line width change amount ΔW that corrects (j) to the line width Wmin is calculated as the light amount correction amounts ΔEa to ΔEj. The light source control unit 89 adjusts the light amount of the laser beam L output from each of the light source units 28a to 28j according to the calculated light amount correction amounts ΔEa to ΔEj (step S10).

  On the other hand, the mask data setting unit 86 sets the line widths Wa (x) to Wj (x), which are different due to the locality of the light amount of each DMD 36 constituting each exposure head 24a to 24j, to each minimum value Wmin (a). A light amount correction amount ΔMa (x) to ΔMj (x) (see FIG. 12) to be corrected to Wmin (j) is calculated using the light amount / line width table memory 87, and a light amount correction amount ΔMa (x) to ΔMj (x ), The initial mask data set in step S4 is adjusted to set mask data (step S11). The mask data is determined according to the light amount correction amounts ΔMa (x) to ΔMj (x), among the plurality of micromirrors 40 that form one pixel of the image at each position x of the substrate F. It is set as data to be used. The set mask data is stored in the mask data memory 82 instead of the initial mask data.

The mask data is, for example, light amount correction amounts ΔMa (x) to ΔMj (x) with respect to the light amounts Ea (x) to Ej (x) (see FIG. 6) when the output data is corrected using the initial mask data. Using the ratio and the number N of the plurality of micromirrors 40 that form one pixel, the number n of the micromirrors 40 that are controlled to be turned off is
n = N · ΔMk (x) / Ek (x) (k: a to j)
And n micromirrors 40 out of N may be set to be in an off state.

  After setting the mask data as described above, an exposure recording process of a desired wiring pattern on the substrate F is performed (step S12).

  Therefore, image data related to a desired wiring pattern is input from the image data input unit 70. The input image data is stored in the frame memory 72, then supplied to the resolution conversion unit 74, converted into a resolution corresponding to the resolution of the DMD 36, and supplied to the output data calculation unit 76. The output data calculation unit 76 calculates output data that is an on / off signal of the micromirror 40 constituting the DMD 36 from the image data whose resolution has been converted, and supplies the output data to the output data correction unit 78.

  The output data correction unit 78 reads the mask data set in step S11 from the mask data memory 82, corrects the on / off state of each micromirror 40 set as output data with the mask data, and the corrected output data Is supplied to the DMD controller 42. The DMD controller 42 drives the DMD 36 based on the corrected output data, and controls each micromirror 40 on and off.

  On the other hand, the light source units 28 a to 28 j introduce a laser beam L having a light amount adjusted by the light source control unit 89 into each exposure head 24 a to 24 j via the optical fiber 30. The laser beam L enters the DMD 36 from the rod lens 32 through the reflection mirror 34. The laser beam L selectively reflected in a desired direction by the respective micromirrors 40 constituting the DMD 36 is expanded by the first imaging optical lenses 44 and 46, and then the microaperture array 54, the microlens array 48, and the microlens. It is adjusted to a predetermined diameter via the aperture array 56, and then adjusted to a predetermined magnification by the second imaging optical lenses 50 and 52 and guided to the substrate F. The exposure stage 18 moves along the surface plate 14, and a desired wiring pattern is exposed and recorded on the substrate F by a plurality of exposure heads 24a to 24j arranged in a direction orthogonal to the moving direction of the exposure stage 18. .

  The substrate F on which the wiring pattern is exposed and recorded is removed from the exposure apparatus 10 and then subjected to development processing, etching processing, and peeling processing. In this case, since the light quantity of the laser beam L irradiated to the board | substrate F is adjusted in consideration of the last process process to peeling process, the highly accurate wiring pattern which has a desired line width can be obtained.

  In the above-described embodiment, the test pattern 90 shown in FIG. 11 is exposed and recorded on the substrate F, and the line widths Wa (x) to Wj (x) are measured to obtain the light amount correction amount and mask data of the laser beam L. However, the light amount correction amount and the mask data may be obtained by measuring the space width of the test pattern 90. In addition, when it is difficult to measure each line width Wa (x) to Wj (x) or each space width with high accuracy, the density of a small region centering on each position x of the test pattern 90 is measured, Mask data may be obtained based on the density distribution.

  Further, instead of exposing and recording the test pattern 90 on the substrate F, as shown in FIG. 14, a halftone dot pattern 91 consisting of a predetermined halftone dot is exposed and recorded on the substrate F, and the halftone dot density or density is measured to measure the mask. Data may be obtained.

  Further, as test data, gray scale data 92 of n (n = 1, 2,...) Steps shown in FIG. 15 is set in the test data memory 80, and the gray scale data 92 is used to make the direction of arrow y on the substrate F. After the exposure and recording of the gray scale pattern in which the light amount increases stepwise, the development process, the etching process, and the peeling process are performed, and then the range of the copper foil pattern 94 remaining on the substrate F is measured as shown in FIG. Then, the step number n (x) of the corresponding step of the gray scale data 92 at each position x of the copper foil pattern 94 may be obtained, and the mask data may be obtained based on the step number n (x).

  In the embodiment described above, exposure processing, development processing, etching processing, and peeling processing are performed, and the mask data is obtained by measuring the finally obtained test pattern. Mask data may be obtained by measuring test data as a pattern.

  Instead of the test pattern 90, mask data may be obtained by measuring the line width or space width of each test pattern arranged in two different directions. For example, as shown in FIG. 17, at each position x of the substrate F, a test pattern 96a parallel to the scanning direction (arrow y direction) and a test pattern 96b parallel to the direction orthogonal to the scanning direction (arrow x direction) May be drawn as a set, and the mask data may be obtained by calculating the light amount correction amount based on the average value of the line widths of the test patterns 96a and 96b. In this way, by using test patterns arranged in two different directions, it is possible to eliminate the influence of the line width variation factor that depends on the direction of the test pattern.

  As one of the line width variation factors, it is conceivable that the method of drawing the edge portion of the test pattern differs between the scanning direction and the direction orthogonal thereto. That is, as shown in FIG. 18, the edge portion 98 a in the scanning direction (arrow y direction) of the substrate F moves in the arrow y direction in which one or a plurality of beam spots of the laser beam L is the moving direction of the substrate F. In contrast, the edge portion 98b in the direction of the arrow x is drawn by a plurality of beam spots of the laser beam L that does not move with respect to the substrate F, as shown in FIG. Accordingly, there is a possibility that a difference in line width may occur due to the difference in the drawing method of the edge portions 98a and 98b. Similarly, even when the beam spot shape is not a perfect circle, the line width may vary.

  As an arrangement direction of the test pattern, not only the above two directions but also three or more directions may be used, and a test pattern inclined with respect to the arrow x and y directions may be used. Further, the light quantity may be corrected by forming a predetermined circuit pattern as a test pattern and measuring the circuit pattern.

  Also, a plurality of mask data corresponding to the type of photosensitive material applied to the substrate F is created and stored in the mask data memory 82, and the corresponding mask data is selected according to the type of photosensitive material to adjust and output the light amount. Data correction may be performed.

  That is, as shown in FIG. 20, the relationship between the light quantity change amount ΔE and the line width change amount ΔW of the laser beam L irradiated to the substrate F, or the beam diameter change amount and the line width change amount ΔW of the laser beam L This relationship may differ depending on the types of the photosensitive materials A and B. These differences are caused by differences in the gradation characteristics of the photosensitive materials A and B. For example, as shown in FIG. 21, even when a test pattern is drawn under the same conditions, different line widths W It may become. In FIG. 20, the relationship between the light quantity change amount ΔE and the line width change amount ΔW is shown by linear approximation.

  In order to draw a pattern with the same line width regardless of the difference in the characteristics of the photosensitive materials A and B, the light amount change amount ΔE−the line width change amount ΔW characteristic for each of the photosensitive materials A and B (FIG. 20) From the line width change amounts ΔWA and ΔWB (FIG. 21) with respect to the reference line width W0 (in this case, for example, the minimum value of the line width W) at each position x for each of the photosensitive materials A and B, It is necessary to set a light amount correction amount according to the materials A and B. FIG. 22 shows an example of the light amount correction amount set for each of the photosensitive materials A and B.

  In this embodiment, the mask data setting unit 86 sets each mask data based on the light amount correction amount obtained for each of the photosensitive materials A and B, and stores the mask data in the mask data memory 82. When exposure processing of a desired wiring pattern is performed on the substrate F, for example, mask data corresponding to the type of photosensitive material input by the operator is read from the mask data memory 82 and supplied from the output data calculation unit 76. By correcting the output data to be used with the mask data, a highly accurate wiring pattern having no line width variation can be exposed and recorded on the substrate F regardless of the type of photosensitive material.

  Note that the relationship between the light quantity change amount ΔE and the line width change amount ΔW of the laser beam L irradiated to the substrate F may be wavelength-dependent depending on the spectral sensitivity characteristics of the photosensitive material. However, the relationship may differ depending on the wavelength of the laser beam L irradiated to the substrate F from each of the exposure heads 24a to 24j. FIG. 23 illustrates the characteristics of two types of photosensitive materials A and B having different spectral sensitivity characteristics S depending on the wavelength λ.

  Therefore, for example, the wavelength of the laser beam L irradiated to the substrate F is measured for each of the exposure heads 24a to 24j, and the relationship for each photosensitive material with respect to each wavelength is obtained for each of the exposure heads 24a to 24j. It is stored in the table memory 87. Then, the relationship corresponding to the photosensitive material is selected for each of the exposure heads 24a to 24j, mask data is set, and a desired wiring pattern is exposed using the set mask data. By performing exposure recording in this way, it is possible to form a highly accurate wiring pattern that is not affected by variations in the wavelength of the laser beam L irradiated to the substrate F from the exposure heads 24a to 24j. Note that the light amount of the laser beam L output from each of the exposure heads 24a to 24j may be adjusted by the light source control unit 89 according to the photosensitive material.

  As shown in FIG. 24, the relationship between the wavelength λ of the laser beam L and the spectral sensitivity characteristic S for each photosensitive material with respect to the wavelength λ is obtained in advance and stored in the sensitivity characteristic data memory 100 (sensitivity characteristic storage means). The light quantity of the laser beam L output from each of the light source units 28a to 28j may be adjusted using this spectral sensitivity characteristic.

  That is, assuming that the wavelength λ of the laser beam L output from each of the exposure heads 24a to 24j is known in advance, the spectral sensitivity characteristic S in each of the exposure heads 24a to 24j corresponding to the photosensitive material applied to the substrate F is set as a sensitivity. Read from the characteristic data memory 100. Next, for example, as shown in FIG. 23, the spectral sensitivity characteristic S of the photosensitive material A with respect to the reference wavelength λ0 is set to 1.0, and the reciprocal 1 / S of the spectral sensitivity characteristic S in each of the exposure heads 24a to 24j is used as the light amount correction data. calculate. The reference wavelength λ0 is a wavelength at which a desired line width can be obtained when the test pattern 90 is recorded with the laser beam L having the reference light amount E0 having the wavelength λ0. Then, the light source controller 89 adjusts the light amount of the laser beam L output from each light source unit 28a to 28j according to the light amount correction data 1 / S for each of the exposure heads 24a to 24j corresponding to the photosensitive material.

  For example, when the photosensitive material A having the spectral sensitivity characteristic shown in FIG. 23 is selected, the light quantity correction that is the reciprocal of the spectral sensitivity characteristic S1 is applied to the light source units 28a to 28j that output the laser beam L having the wavelength λ1. Based on the data 1 / S1, the reference light amount E0 of the set reference wavelength λ0 is corrected to E0 / S1. For the light source units 28a to 28j that output the laser beam L having the wavelength λ2, the set reference light amount E0 is corrected to E0 / S2 based on the light amount correction data 1 / S2.

  By using the light source units 28a to 28j whose light amounts are adjusted as described above, a wiring pattern having a desired line width can be exposed and recorded on the selected photosensitive material. The light quantity of the laser beam L output from each of the exposure heads 24a to 24j can be adjusted by setting mask data.

  On the other hand, the line width of the wiring pattern exposed and recorded on the substrate F is affected by the beam diameter of the laser beam L as shown in FIG. This relationship differs depending on the gradation characteristic which is one of the sensitivity characteristics of the photosensitive material. For example, when the gradation characteristic changes, the density of the wiring pattern recorded on the substrate F and the film thickness of the resist 3 shown in FIG. 27 change, and as a result, the line width changes.

  Therefore, as shown in FIG. 26, the beam diameter of the laser beam L output from each of the exposure heads 24 a to 24 j is measured in advance and stored in the beam diameter data memory 102. Further, the relationship between the beam diameter of the laser beam L shown in FIG. 25 and the line width of each photosensitive material with respect to the beam diameter is obtained in advance and stored in the beam diameter / line width table memory 104 (relation storage means). The light quantity of the laser beam L output from each light source unit 28a-28j is adjusted using this relationship.

  That is, the beam diameter of the laser beam L output from each exposure head 24a-24j is read from the beam diameter data memory 102, and then the beam diameter for each exposure head 24a-24j corresponding to the photosensitive material applied to the substrate F. Is read from the beam diameter / line width table memory 104. And the light quantity of the laser beam L output from each light source unit 28a-28j is adjusted so that line width may be desired line width. As a result, a wiring pattern having a desired line width can be exposed and recorded on the selected photosensitive material. Instead of using the beam diameter stored in the beam diameter data memory 102, the beam diameter may be measured for each of the exposure heads 24a to 24j. Further, the light amount of the laser beam L output from each of the exposure heads 24a to 24j can be adjusted by setting mask data.

  The above-described exposure apparatus 10 is, for example, a dry film resist (DFR) or liquid resist exposure in a manufacturing process of a multilayer printed wiring board (PWB), or a liquid crystal display (LCD). It can be suitably used for applications such as color filters in the process, black matrix formation, DFR exposure in the TFT manufacturing process, and DFR exposure in the plasma display panel (PDP) manufacturing process. The present invention can also be applied to an exposure apparatus in the printing field and the photographic field.

It is an external appearance perspective view of the exposure apparatus of this embodiment. It is a schematic block diagram of the exposure head in the exposure apparatus of this embodiment. It is explanatory drawing of DMD which comprises the exposure head shown in FIG. It is explanatory drawing of the exposure recording state by the exposure head shown in FIG. It is explanatory drawing of DMD which comprises the exposure head shown in FIG. 2, and the mask data set to it. It is explanatory drawing of the relationship between the recording position in the exposure apparatus of this embodiment, and light quantity locality. It is explanatory drawing of the line | wire width recorded when not correcting light quantity locality shown in FIG. It is explanatory drawing of the line | wire width recorded when the light quantity locality shown in FIG. 6 was correct | amended. It is a control circuit block diagram in the exposure apparatus of this embodiment. It is a flowchart of the light quantity correction process and image exposure process in the exposure apparatus of this embodiment. It is explanatory drawing of the test pattern exposed and recorded on the board | substrate by the exposure apparatus of this embodiment. FIG. 12 is an explanatory diagram of the relationship between the position of the test pattern shown in FIG. 11 and the measured line width for each exposure head. FIG. 5 is an explanatory diagram of a relationship between a light amount change amount of a laser beam irradiated on a substrate and a line width change amount associated therewith. It is explanatory drawing of the halftone dot pattern exposure-recorded on the board | substrate by the exposure apparatus of this embodiment. It is explanatory drawing of the gray scale data which are test data. It is explanatory drawing of the copper foil pattern formed in the board | substrate using the gray scale data shown in FIG. It is explanatory drawing of the other structure of the test pattern exposed and recorded on the board | substrate by the exposure apparatus of this embodiment. It is explanatory drawing of the edge part formed in the scanning direction of a board | substrate. It is explanatory drawing of the edge part formed in the direction orthogonal to the scanning direction of a board | substrate. FIG. 6 is an explanatory diagram of a relationship between a light amount change amount and a line width change amount in different types of photosensitive materials. FIG. 6 is a diagram illustrating the relationship between the position of a substrate and the line width in different types of photosensitive materials. FIG. 7 is an explanatory diagram of a relationship between a position of a substrate and a light amount correction amount in different types of photosensitive materials. It is explanatory drawing of the spectral sensitivity characteristic of a photosensitive material. It is a control circuit block diagram of other embodiment. It is an explanatory view of the relationship between the beam diameter and the line width. It is a control circuit block diagram of further another embodiment. It is explanatory drawing of the manufacturing process of a printed wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus 14 ... Surface plate 18 ... Exposure stage 22a, 22b ... CCD camera 24a-24j ... Exposure head 26 ... Scanner 28a-28j ... Light source unit 36 ... DMD
42 ... DMD controller 68 ... Photo sensor 78 ... Output data correction unit 80 ... Test data memory 82 ... Mask data memory 86 ... Mask data setting unit 87 ... Light quantity / line width table memory 88 ... Light quantity locality data calculation part 89 ... Light source control part 90, 96a, 96b ... Test pattern 92 ... Gray scale data 94 ... Copper foil pattern F ... Substrate L ... Laser beam

Claims (12)

In an image recording method for controlling a plurality of exposure heads arranged along an image recording medium having a light source that outputs a light beam according to image data, and recording an image on the image recording medium,
Obtaining the beam diameter of each light beam guided from each exposure head to the image recording medium for each exposure head;
Based on the relationship of the recording state of the image recorded on the image recording medium with respect to the beam diameter of the light beam, each light beam is adjusted to adjust the recording state of the image recorded on the image recording medium by each exposure head. Correcting the amount of light,
Controlling each of the exposure heads according to the image data, and recording an image on the image recording medium using the light beams whose light amounts have been corrected;
An image recording method comprising: The method of claim 1 , wherein
The image recording method according to claim 1, wherein the relationship is set in accordance with sensitivity characteristics of the image recording medium. The method of claim 2 , wherein
The image recording medium according to claim 1, wherein the image recording medium has spectral sensitivity characteristics having different sensitivities depending on the wavelength of the light beam. The method of claim 1 , wherein
An image recording method, wherein the light amount of the light beam is corrected by adjusting the light sources of the exposure heads. The method of claim 1 , wherein
The exposure heads is provided with a spatial light modulator having a plurality of spatial light modulation element for guiding the light beam to the image recording medium by modulating according to said image data,
An image recording method, wherein the light quantity of the light beam is corrected by controlling a specific spatial light modulation element constituting each spatial light modulation element included in each exposure head to be in an OFF state. The method of claim 1 , wherein
An image recording method comprising: correcting a light quantity of the light beam based on the relationship so that an image recording state by the exposure head is constant regardless of a position in the exposure head. When a plurality of exposure heads having a light source that outputs a light beam and arranged along the image recording medium are controlled according to image data, and an image is recorded on the image recording medium,
Obtaining the beam diameter of each light beam guided from each exposure head to the image recording medium for each exposure head;
Based on the relationship of the recording state of the image recorded on the image recording medium with respect to the beam diameter of the light beam, each light beam is adjusted to adjust the recording state of the image recorded on the image recording medium by each exposure head. A method for adjusting the amount of light characterized by adjusting the amount of light. In an image recording apparatus that has a light source that outputs a light beam and controls a plurality of exposure heads arranged along an image recording medium according to image data, and records an image on the image recording medium.
Relationship storage means for storing a relationship of a recording state of an image recorded on the image recording medium with respect to a beam diameter of the light beam;
A beam diameter of each light beam guided from each exposure head to the image recording medium is acquired for each exposure head, and the image recorded on the image recording medium by each exposure head is obtained based on the relationship. A light amount correcting means for correcting the light amount of each light beam in order to adjust the recording state;
Exposure head control means for controlling each exposure head according to the image data and recording an image on the image recording medium using each light beam whose light amount has been corrected;
An image recording apparatus comprising: The apparatus of claim 8 .
The relationship storage means stores the relationship corresponding to sensitivity characteristics of the image recording medium. The apparatus of claim 8 .
The image recording apparatus, wherein the light amount correction unit corrects the light amount of the light beam by adjusting the light sources of the exposure heads. The apparatus of claim 8 .
Each exposure head includes a spatial light modulation element having a plurality of spatial light modulation elements that modulate the light beam according to the image data and guide the light beam to the image recording medium,
The light amount correction unit corrects the light amount of the light beam by controlling a specific spatial light modulation element constituting each spatial light modulation element included in each exposure head to be in an off state. Image recording device. The apparatus of claim 8 .
An image comprising second light amount correction means for correcting the light amount of the light beam so as to make the recording state of the image by the exposure head constant regardless of the position in the exposure head based on the relationship. Recording device.

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