JP2009244808A - Distance measuring method, and exposure device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform high-definition image exposure by use of a distance sensor having a small measuring range or a limited measuring distance and provided with a hold function. <P>SOLUTION: A control unit causes in advance a laser light source part to emit light, starts measuring movement of a moving table with a substrate material placed thereon, reads a distance D measured by the distance sensor at a distance measurement time, and terminates the reading of the distance D at a measurement end time (steps 100-110). Thereafter, the control unit confirms whether scanning exposure to the substrate material is started or not, stops the light emission of the laser light source part when exposure processing is started, and releases the holding of the measurement value in the distance sensor (steps 112 and 114) to prevent a measurement error for the substrate material out of a valid range due to the held measurement value. When the scanning exposure to the substrate material ends, the control unit starts the light emission in the laser light emission part to measure the distance to the next substrate material (steps 116 and 118). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exposure apparatus that exposes a predetermined image such as a print pattern to an exposure target such as a printed circuit board, and measures the distance of the exposure target using a high-precision distance sensor having a narrow measurable range. The present invention relates to a method and an exposure apparatus.

  In an exposure apparatus that targets a substrate material such as a printed wiring board as an exposure target, the substrate material is placed on an exposure stage, and a light beam is modulated by a spatial modulation element or the like based on image data having a wiring pattern as an image. Scanning is performed to expose the wiring pattern on the substrate material.

  In such an exposure apparatus, by supplying negative pressure to a large number of small holes formed on the exposure stage, the entire surface of the substrate material is brought into close contact with the exposure stage, and floating or the like occurs in the substrate material, resulting in an exposure image. Prevents distortions from occurring. Further, in the exposure apparatus, an alignment hole, a mark (alignment mark) or the like that is previously formed at a predetermined position of the substrate material is positioned so as to be disposed at the predetermined position.

  On the other hand, in order to perform high-definition image exposure, it is necessary to accurately focus the light beam on the exposure surface on the substrate material. From here, the exposure apparatus moves the exposure stage to move the substrate material and the distance sensor to measure the distance to the exposure surface of the substrate material on the exposure stage. The image is exposed while moving relative to the lens and performing focus adjustment based on the measurement distance.

  In general, as a distance measuring device that measures the focal length in a non-contact manner, a laser beam is irradiated onto the measurement target, the reflected light from the measurement target is received, and the distance from the electrical signal according to the amount of received light to the target (For example, refer to Patent Document 1 and Patent Document 2).

  By the way, a distance sensor capable of measuring a distance with high accuracy has a narrow range width, which is a measurable band, and a measurable distance is limited. With such a distance sensor, if the measured distance is within the measurable distance range (hereinafter referred to as the measurement range), the distance can be measured with high accuracy. Any one of the maximum value and the minimum value in the case is output as a measurement value. For this reason, if it is out of the next measurement range, it is unclear whether the distance to the substrate material is short or far.

From this point, some distance sensors capable of measuring distances with high accuracy have a function of holding a measurement value (hold function). With this distance sensor, when the substrate material is within the measurement range, the distance can be measured with high accuracy.When the substrate material gradually approaches and goes out of the measurement range, the minimum value of the measurement range is output, When the substrate material gradually moves away from the measurement range, the maximum value of the measurement range is output. For this reason, it is possible to grasp whether the distance to the substrate material is large or small.
Japanese Utility Model Publication No. 5-34595 JP 2001-249019 A

  However, in the distance sensor having a hold function, when the distance sensor changes rapidly at the end of the substrate material and goes out of the measurement range, the previous measurement value is held. Further, in this distance sensor, if the measurement value is held, the held measurement value is continuously output even if the substrate material with a distance outside the measurement range passes next. Since the measurement value at this time is an effective measurement value within the measurement range, a measurement error occurs.

  As a result, it becomes difficult to perform image exposure with a light beam whose focal length is adjusted with high accuracy, resulting in a problem that the exposure quality is deteriorated.

  The present invention has been made in view of the above-mentioned fact, and the distance to the exposure object is measured using a distance sensor having a narrow measurement range and a limited measurement distance and having a hold function, and based on the measurement result. An object of the present invention is to provide a distance measuring method and an exposure apparatus that enable high-quality image exposure when performing image exposure with focus adjustment.

  In order to achieve the above object, the present invention sets the focal length according to the distance to the exposure target when the exposure target with the photosensitive layer formed on the surface of the support is exposed by irradiating a light beam while scanning. In the exposure apparatus to be adjusted, when the distance to the measurement target is within a predetermined range set in advance, the light receiving unit receives reflected light of the laser light emitted from the light source and applied to the measurement target. And when the measured value changes at the end of the measurement object and deviates from the measurement range, the previous measured value is held in the predetermined range, and the measured value falls within the predetermined range. A distance measuring method for measuring a distance for adjusting the focal position with the exposure target as the measurement target, using a distance sensor formed with a holding unit that continues to hold the measurement value. And said Prior to the light target passing through the light irradiation position of the distance sensor, light emission from the light source is started, and the distance to the exposure target when the exposure target passes through the light irradiation position of the distance sensor. The measurement value is held and released by the holding unit prior to the next measurement of the distance to the exposure target.

  According to this invention, for example, when measuring a distance for adjusting the focal length when exposing the exposure target with the measurement target as the exposure target, using a distance sensor having a narrow measurable distance and distance range. Prior to the distance measurement, light emission from the light source is started to stabilize the laser beam. Thus, if the distance to the exposure target is within a measurable range, the distance can be accurately measured.

  Further, when the measurement position deviates from the exposure target, the previous measurement value is held by the holding means. In addition, the holding of the measurement value by the holding unit is released until the next exposure target measurement is started.

  As a result, when measuring the distance of the next exposure target, even if the distance of the exposure target is out of the measurable range, it is surely prevented from being erroneously measured as an effective distance of the measurable range. Can do.

  According to a second aspect of the present invention, the distance sensor measures the distance to the next exposure target when the holding of the measurement value by the holding unit is released by stopping the light emission of the light source. In advance, the light emission of the light source is stopped.

  According to this invention, when using the distance sensor in which the holding unit releases the measurement value by stopping the light emission of the light source unit, the light emission of the light source unit is stopped prior to the distance measurement.

  This cancels the retention of the measurement value, so that even if the distance of the next exposure target is outside the measurable range, it is possible to reliably prevent erroneous measurement as an effective distance of the measurable range. it can.

  The invention according to claim 3 is characterized in that the release of the measurement value due to the light emission stop of the light source is performed during the exposure of the exposure object based on the measurement result of the distance sensor.

  According to the present invention, the light emission of the light source unit is stopped during the exposure of the exposure target. Accordingly, it is possible to reliably prevent the occurrence of erroneous measurement while suppressing the exposure to the object to be exposed.

  An exposure apparatus to which the present invention is applied includes an exposure head that can irradiate an exposure target with a light beam as exposure light, and a focus adjustment that is provided on the exposure head and that can adjust the focal position of the light beam. Means, a light source that emits laser light, a light receiving unit that receives the laser light emitted from the light source and reflected by the exposure target, and calculates a distance from the laser light received by the light receiving unit to the surface of the exposure target A distance calculation unit that outputs a calculated distance when the calculated distance is within a preset effective range, and a distance within the previous effective range when the distance calculated by the distance calculation unit is out of the effective range A distance sensor including a holding unit that holds the distance so as to be output; a moving unit that moves the exposure target relative to the exposure head and the processing sensor; and Exposure control means for performing an exposure process by controlling the light beam emitted from the exposure head based on image data of an image to be exposed to the exposure object when the light object is moved while facing the exposure head; Prior to the exposure process on the exposure object, distance measurement control means for measuring the distance to the exposure object moved while facing the distance sensor by the moving means, and the exposure process on the exposure object. When performing the adjustment control means, the distance measurement control means operates the focus adjustment means based on the distance measured by the distance sensor so as to adjust the focus position of the light beam to the surface of the exposure target. And after the distance measurement means finishes measuring the distance by the distance sensor until the image exposure to the exposure target ends And hold releasing means for releasing the retention of the distance which the distance sensor by said holding means outputs may include.

  As described above, according to the present invention, since the holding of the previous measurement value is canceled prior to the measurement of the distance to the exposure target, erroneous measurement occurs even if the next exposure target is out of the measurement range. As a result, it is possible to reliably prevent the quality of the image to be exposed from being deteriorated.

  In the exposure apparatus of the present invention, high-definition image exposure can be performed with a light beam emitted as exposure light from an exposure head.

  Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a schematic configuration of an exposure apparatus 10 applied to the present embodiment. In the present embodiment, a so-called multi-beam exposure apparatus that exposes an exposure target using a plurality of light beams as the exposure apparatus 10 will be described. However, the configuration of the present invention is not limited to this.

  As shown in FIG. 1, a so-called flat bed type is applied to the exposure apparatus 10, which includes a long rectangular base 12, which is supported on the floor surface by a plurality of leg members 12 </ b> A. In addition, the upper surface is supported in a horizontal state.

  A pair of guide rails 14 are attached to the upper surface of the base 12 along the longitudinal direction, and a moving stage 16 is provided on the guide rails 14. As shown in FIG. 2, the stage 12 is provided with a stage driving unit 18. Thereby, the moving stage 16 shown in FIG. 1 can reciprocate along the longitudinal direction of the base 12. At this time, the moving stage 16 is reciprocated at a predetermined constant speed such as a speed of about 40 mm / sec.

  The exposure apparatus 10 according to the present embodiment is, for example, a printed circuit board (PCB), a color liquid crystal display (LCD) panel, a plasma display panel (PDP), or the like, such as a photosensitive epoxy resin on the surface of a substrate or a glass plate. Various photosensitive materials such as those coated with a photoresist and those obtained by laminating a photoresist resin and a dry film are used as exposure objects and are applied to the exposure of these photosensitive materials. Below, the photosensitive material used as exposure object is demonstrated as the board | substrate material 20 with which the photosensitive layer was formed in the surface of a board | substrate member. In FIG. 1, the moving direction of the moving stage 16 is indicated by an arrow Y direction, and the width direction of the base 12 that is orthogonal to the moving direction of the moving stage 16 is indicated by an arrow X direction.

  In the exposure apparatus 10, one end side in the longitudinal direction of the base 12 is set as an original position of the moving stage 16 (for example, a position indicated by a two-dot chain line on the back side in FIG. 1). The exposure apparatus 10 is provided with a carry-in transport means 22 on one side in the direction of the arrow X across the original position of the moving stage 16 and a carry-out transport means 24 on the other side. The substrate material 20 is transported by the carry-in transport means 22, placed on a predetermined position on the moving stage 16 that is waiting at the original position, and discharged from the moving stage 16 at this original position.

  Thereby, in the exposure apparatus 10, the substrate material 20 continuously fed from the carry-in transport means 22 can be subjected to exposure processing in order and discharged. In addition, arbitrary structures, such as a conveyor, are applicable to the carrying-in conveyance means 22 and the carrying-out conveyance means 24. FIG. Further, in the exposure apparatus 10, at least the base 12 is shielded from light, thereby preventing unnecessary exposure of the substrate material 20 placed and moved on the moving stage 16.

  On the other hand, as shown in FIGS. 1 and 2, the exposure apparatus 10 includes a light source unit 26, an exposure head unit 28, and a control unit 30 that controls the operation of the exposure apparatus 10. As shown in FIG. 1, the base 12 is provided with a gate-type gate 32 disposed so as to straddle the base 12 in the width direction at an intermediate portion in the longitudinal direction. The gate 32 is exposed to light. A head unit 28 is attached. Thereby, in the exposure apparatus 10, the substrate material 20 is passed under the exposure head unit 28 by the movement of the moving stage 16 along the arrow Y direction.

  In the exposure head unit 28, a number of exposure heads 34 from which light beams are emitted are arranged, for example, in a matrix. Also, for example, a bundle-shaped optical fiber array 36 is provided between the light source unit 26 and the exposure head unit 28, and one end side of the optical fiber array 36 is connected to the exposure head 34 of the exposure head unit 28, and the like. The end side is connected to the light source unit 26.

  The light source unit 26 is provided with a number of light sources (not shown) that emit light beams including light in a predetermined wavelength range (for example, an ultraviolet wavelength range). Each of the optical fiber arrays 36 is formed by bundling a large number of optical fibers, and light beams emitted from the respective light sources of the light source unit 26 are incident on the optical fibers of the optical fiber array 36. As a result, multiple light beams are introduced into the exposure head unit 28 by the optical fiber array 36. The substrate material 20 is scanned and exposed by being irradiated with the light beam introduced into the exposure head 34 while being moved on the base 12.

  The control unit 30 includes, for example, a microcomputer having a general configuration in which a CPU, ROM, RAM, and the like are connected by a bus, a display device such as a display, an input device such as a keyboard, and various data input / output devices. It includes an input / output interface for performing input / output and a drive circuit for driving various devices.

  In the exposure apparatus 10, the movement of the moving stage 16 on the base 12 and the operation of the light source unit 26, the exposure head unit 28 (each exposure head 34), and the like are controlled by the control unit 30. At this time, the control unit 30 generates a modulation signal for scanning the light beam from image data of an image (for example, a print pattern) to be exposed on the substrate material 20 and outputs the modulation signal to the exposure head unit 28. The deflection of the light beam applied to the substrate material 20 from each exposure head 34 is controlled. Thereby, the substrate material 20 on the moving stage 16 is exposed according to the image data.

  On the other hand, a distance sensor 40 is provided at the gate 32 of the base 12 together with the exposure head unit 28. For example, the distance sensors 40 are arranged in pairs along the width direction of the base 12 and are moved relative to the substrate material 20 by the movement of the moving stage 16. In the exposure apparatus 10 applied to the present embodiment, as an example, the exposure head unit 28 is disposed on the original position side of the moving stage 16, and the distance sensor 40 is disposed on the opposite side to the original position. In the present embodiment, two distance sensors 40 are provided as an example. However, the present invention is not limited to this, and one distance sensor 40 is provided in an intermediate portion in the width direction of the base 12. Moreover, the structure which has arrange | positioned three or more distance sensors 40 along the width direction of the base 12 may be sufficient.

  As shown in FIGS. 1 and 2, the distance sensor 40 is connected to the control unit 30. In the exposure apparatus 10, the moving stage 16 on which the substrate material 20 is placed is moved along the arrow Y direction from the original position. At this time, the control unit 30 measures the distance of the substrate material 20 by the distance sensor 40. The control unit 30 also adjusts the focus of the light beam emitted from the exposure head 34 based on the measurement result. Thereby, the control unit 30 makes the focus of the light beam irradiated from each exposure head 34 coincide with the exposure surface of the substrate material 20 so that a high-definition image is exposed.

  The control unit 30 determines the position of the substrate material 20 relative to the moving stage 16, that is, the exposure amount area, and performs alignment adjustment so that the light beam is scanned into the determined exposure area. For such alignment adjustment, for example, an alignment mark or a reference hole is formed as a reference position for alignment in the substrate material 20, or a plurality of positions such as corners are set (not shown), and the control unit 30 has a plurality of positions. By calculating each coordinate of the reference position, creating displacement data of the exposure region, and correcting the image data based on this displacement data, a scanning region is moved to a predetermined region on the substrate material 20. Appropriate image exposure is performed. The alignment adjustment is not limited to this, and any known method can be applied. In the following, the movement of the moving stage 16 along the arrow Ym direction from the original position is referred to as a measurement movement, and the movement of the moving stage 16 returning to the original position along the arrow Ye direction is referred to as a scanning movement.

  As shown in FIG. 3, the exposure head unit 28 has a number of exposure heads 34 arranged in a matrix. In the exposure apparatus 10, the exposure head 34 is provided in the exposure head unit 28 so that the exposure head 34 faces the entire area of the substrate material 20 along the arrow X direction. In each exposure head 34, the light beam irradiable area 44A has a rectangular shape, and the short side of the irradiable area 44A is inclined at a predetermined angle with respect to the arrow Y direction.

  In the exposure head unit 28, the even-numbered exposure heads 32 are arranged between the odd-numbered exposure heads 34, and irradiation along the arrow X direction is possible between the adjacent exposure heads 34 along the arrow X direction. The end portions of the region 44A overlap each other. As a result, the ends of the light beam irradiable lines 44B by the exposure head 34 adjacent in the direction of the arrow X overlap each other, and the exposure apparatus 10 emits a light beam to the entire exposure surface of the substrate material 20 by one scanning movement. Irradiation is possible.

  4A and 4B show an example of the exposure head 34 provided in the exposure head unit 28. FIG. 4A is a schematic view seen from one end side (one side of the long side) along the short side direction of the irradiable region 44A, and FIG. 4B is a long side direction of the irradiable region 44A. It is the schematic seen from the one end side (one side of a short side) along.

  The exposure head 34 includes a digital micromirror device (hereinafter referred to as DMD 46) as a spatial light modulation element that modulates a light beam for each pixel. The DMD 46 includes a large number of micromirrors (not shown) each corresponding to a single pixel, and each of the multiple light beams guided by the optical fibers of the optical fiber array 36 from the light source unit 26 corresponds to the micromirrors of the DMD 46. The mirror is irradiated.

  The DMD 46 is driven so that the inclination angle of the micromirror corresponding to each pixel is switched based on the modulation signal for each pixel input from the control unit 30. Thereby, in the exposure head 34, the light beam irradiated to the micromirror is deflected. At this time, the micromirror corresponding to the pixel to be exposed reflects the light beam toward the substrate material 20, and the micromirror corresponding to the pixel not to be exposed reflects the light beam toward the light absorbing member (not shown). To do. A known configuration can be applied to such DMD 46.

  Each optical fiber of the optical fiber array 36 is arranged and connected to the exposure head 34 in a direction orthogonal to the short side. The exposure head 34 corrects the light beam emitted from the optical fiber between the light beam emitting end of the optical fiber array 36 and the DMD 46, and transmits the lens system 48 and the lens system 48 that collect the light on the DMD 46. A reflecting mirror 50 is disposed that reflects the light beam directed toward the DMD 46.

  The lens system 48, for example, corrects the light quantity distribution of each pair of combined light beams 48A, which is a pair of combined lenses 48A that make the multiple light beams emitted from the optical fiber array 36 parallel light. A pair of combination lenses 48B and a condensing lens 48C for condensing each corrected light beam on the DMD 46 are formed. In the lens system 48, the combined lens 48B expands the light beam of the light beam close to the optical axis of the lens and contracts the light beam of the light beam away from the optical axis of the lens in the arrangement direction of the light beam. In the direction orthogonal to the direction, the light beam is transmitted as it is, so that the light quantity distribution is corrected to be uniform.

  In the exposure head 34, on the light beam reflection side of the DMD 46, lens systems 52 and 54 that form an image of the light beam reflected by the DMD 46 on the exposure surface on the substrate material 20, and a light beam transmitted through the lens systems 52 and 54. An autofocus unit 56 for adjusting the focal point (focal length) is sequentially arranged. In the exposure head 34, lens systems 52 and 54 are arranged so that the DMD 46 and the exposure surface of the substrate material 20 have a conjugate relationship.

  The control unit 30 controls the autofocus unit 56 based on the distance detected by the distance sensor 40 so that the focus of each light beam coincides with the exposure surface of the substrate material 20 by the exposure head 34. (Focus control).

  The autofocus unit 56 applied as an example in the present embodiment includes a pair of paired wedge glasses 58 and 60 formed in a wedge shape (trapezoidal column shape) from a transparent glass material. The pair of wedge glasses 58 and 60 are set to have a predetermined refractive index (for example, the refractive index n is n = 1.53), and are adjacently disposed along the optical axis of the light beam in directions opposite to each other.

  The pair wedge glass 58 arranged on the DMD 46 side is directed to the DMD 46 side with a light incident surface 58A on the side formed perpendicular to both side surfaces. In the pair wedge glass 58, the surface opposite to the light incident surface 58A is inclined with respect to the optical axis, and this surface is directed to the pair wedge glass 60 as the light exit surface 58B.

  Similarly to the pair wedge glass 58, the pair wedge glass 60 disposed on the substrate material 20 side has one surface formed at right angles to both side surfaces and the other surface inclined with respect to the side surfaces. In the wedge glass 60, the inclined surface is opposed to the light emitting surface 58B of the pair wedge glass 58 as the light incident surface 60A, and the surface formed at right angles is opposed to the substrate material 20 as the light emitting surface 60B. Are arranged as follows. In the autofocus unit 56, the light emitting surface 58B of the pair wedge glass 58 and the light incident surface 60A of the pair wedge glass 60 are parallel to each other with a predetermined gap (for example, 0.1 mm). Installed on.

  In the autofocus unit 56, the pair of wedge glasses 58 and 60 are operated with respect to the optical axis in a state in which the light exit surface 58B and the light incident surface 60A are kept parallel by the operation of an actuator (for example, a focus motor) (not shown). Relatively moved in the orthogonal direction. As a result, the transmission distance when the light beam passes through the paired wedge glasses 58 and 60 changes, and the focal length FD of the light beam changes.

  In the exposure apparatus 10, the relative position of each exposure head 34 with respect to the distance sensor 40 is determined or measured in advance, so that the control unit 30 faces each exposure head 34 from the detection result of the distance sensor 40. The distance to the surface (exposure surface) of the substrate material 20 to be processed can be calculated. That is, the control unit 30 controls the focal length FD of the exposure head 34 by controlling the actuator of the autofocus unit 56 based on the distance D to the exposure surface of the substrate material 20 detected by the distance sensor 40. ing. At this time, the exposure apparatus 10 can control the focal length FD with high accuracy by using an autofocus unit 56 including a pair of paired wedge glasses 58 and 60. The focus adjusting unit is not limited to the autofocus unit 56, and any configuration can be applied.

  By the way, in the exposure apparatus 10, in order to perform high-definition image exposure on the substrate material 20, in addition to a mechanism capable of adjusting the focal length FD with high accuracy, the distance to the exposure surface of the substrate material 20 is highly accurate. It is necessary to measure. From here, in the exposure apparatus 10, the distance sensor 40 using a laser beam is used.

  As shown in FIG. 5, the distance sensor 40 applied to the present embodiment includes a laser light source unit 62, a light receiving unit 64, and a distance calculation unit 66. In the distance sensor 40, the laser light source unit 62 is driven to emit light, and a laser beam having a predetermined wavelength is irradiated onto the substrate material 20. In the present embodiment, as an example, the laser light source unit 62 emits laser light including visible light.

  The light receiving unit 64 includes, for example, a CCD sensor, receives the reflected light of the laser light irradiated onto the substrate material 20, and outputs an electrical signal corresponding to the received light amount to the distance calculation unit 66. The distance calculation unit 66 calculates the distance D to the upper surface of the substrate material 20 based on the electric signal input from the light receiving unit 64.

  In the distance sensor 40, a laser light source unit 62 and a distance calculation unit 66 are connected to the control unit 30. The control unit 30 controls light emission / stop of the laser light source unit 62 and is calculated by the distance calculation unit 66. The measured distance D is read into the control unit 30.

Here, as shown in FIG. 6, the distance sensor 40, previously reference distance (hereinafter, the distance to D ₀₎ is set, the detection range of the actual distance Dr is, around the distance D _0, The range is ± α ((D ₀ −α) ≦ D ₀ ≦ (D ₀ + α)).

Thus, when the actual distance Dr is (D ₀ −α) ≦ Dr ≦ (D ₀ + α), the distance D output from the distance sensor 40 matches the distance Dr (D = Dr, (D ₀ −α) ≦ D ≦ (D ₀ + α)). That is, in the distance sensor 40, the range width that is the range of the measurable distance Dr is 2 · α, and the measurement range (measurable range) is (D ₀ −α) ≦ Dr ≦ (D ₀ + α). .

Here, the exposure apparatus 10 uses, for example, a distance sensor 40 in which the distance D ₀ is D ₀ = 25 mm and α is α = 1.0 to 1.5 mm (1.5 mm as an example) (D _{In the range of 0−} α) ≦ Dr ≦ (D ₀ + α), it is possible to measure the distance Dr (distance D) with high accuracy on the submicron order (the actual effective range is (D ₀ −α)). <Dr <(D ₀ + α)).

  As shown in FIG. 2, in the exposure apparatus 10, a stage height adjustment unit 68 is provided on the base 12. The stage height adjusting unit 68 can be applied with any configuration for moving the moving stage 16 up and down with the upper surface thereof in a horizontal state, and the illustration in FIG. 1 and the detailed description of the mechanism are omitted.

As shown in FIG. 5, in the exposure apparatus 10, the substrate material 20 placed on the moving stage 16 detected by the distance sensor 40 is matched with the thickness t serving as a reference of the substrate material 20 to be exposed. as distance Dr to the upper surface is a distance D _0, height adjustment of the moving stage 16 (adjustment of the distance Ds of the distance sensor 40 and the moving stage 16) is performed.

On the other hand, in a distance sensor that can measure the distance Dr with high accuracy, for example, at the end portion of the substrate material 20, the measurement position deviates from the substrate material 20, and the distance Dr increases rapidly. When the value falls outside the measurement range, for example, the maximum value (D ₀ + α) or the minimum value (D ₀ -α) within the measurement range is output as the measurement value.

  From here, as shown in FIG. 5, a hold setting unit 70 is formed in the distance sensor 40 provided in the exposure apparatus 10. The hold setting unit 70 is formed, for example, by being written in a storage element (not shown) in the distance sensor 40 as firmware. When the distance Dr detected by the distance sensor 40 changes abruptly and the hold setting unit 70 is out of the measurement range, the distance D output from the distance calculation unit 66 is the value immediately before the measurement range. Holds the measured value so that it becomes the measured value (hold function).

Accordingly, as shown in FIG. 6, in the distance sensor 40, when the measurement object is tilted, the distance D becomes the maximum value (D = D ₀ + α) while the distance Dr is large. When Dr enters the measurement range, a distance D = Dr is obtained (shown by a solid line in FIG. 6). Further, in the distance sensor 40, when the distance Dr decreases and goes out of the measurement range, the distance D becomes the minimum value (D = D ₀ −α) (indicated by a broken line in FIG. 6).

  Further, when the distance Dr gradually increases from outside the measurement range, even if the distance D output from the distance sensor 40 is held at the maximum value by the hold setting unit 70, if the distance Dr falls within the measurement range, The distance D output from the distance sensor 40 is D = Dr (shown by a solid line in FIG. 6).

Thus, in the exposure apparatus 10, even if the exposure process for the substrate material 20 is repeated, the distance Dr of the upper surface of each substrate material 20 is in the range of (D ₀ −α) <Dr <(D ₀ + α) (hereinafter, effective). The distance Dr of each substrate material 20 can be accurately measured.

  On the other hand, since the distance sensor 40 has a hold function, when the distance D is held, the substrate material 20 whose distance Dr is within the measurement range passes, so that an appropriate distance D is obtained. When the substrate material 20 whose distance Dr is outside the measurement range passes, the held distance D is continuously output. At this time, since the distance D output from the distance sensor 40 is within the measurement range, the control unit 30 erroneously recognizes the distance Dr of the substrate material 20.

Here, in the hold setting unit 70 provided in the distance sensor 40, when the light emission of the laser light source unit 62 is stopped and the reflected light is not received by the light receiving unit 64, the held measurement value (distance D) is held. Is released. In addition, when the hold of the measurement value in the hold setting unit 70 is released, the distance sensor 40 outputs the maximum value (D ₀ + α) within the measurement range that is out of the effective range as the distance D.

  In the control unit 30, when the operation of the exposure apparatus 10 is started, light emission from the laser light source unit 62 is started prior to scanning exposure on the substrate material 20. Thereby, when measuring the distance Dr of the board | substrate material 20, a laser beam is stabilized and the exact distance D according to the distance Dr is output from the distance sensor 40. FIG.

  Further, in the control unit 30, when the measurement of the distance Dr by the distance sensor 40 is completed, the light emission of the laser light source unit 62 is stopped before the distance Dr of the next substrate material 20 is measured. Accordingly, when the distance Dr of the next substrate material 20 is measured, the measurement value held by the hold setting unit 70 is released.

  Here, in the present embodiment, the light emission of the laser light source unit 62 is stopped during the scanning exposure of the substrate material 20 using the exposure head 34. Accordingly, the hold release is performed while preventing the laser light emitted from the laser light source unit 62 from being applied to the surface of the substrate material 20 during the exposure of the substrate material 20.

  That is, in the distance sensor 40, the hold D is released prior to the measurement of the distance D of the substrate material 20, so that the distance D is effective when the substrate material 20 whose distance Dr is out of the measurement range passes. It does not become a value within the range. Therefore, the control unit 30 can reliably recognize that the distance D of the substrate material 20 that has passed through the distance sensor 40 is outside the measurement range.

  The operation of the present embodiment will be described below.

  In the control unit 30 provided in the exposure apparatus 10, when image data corresponding to an image (exposure pattern) formed on the substrate material 20 is input to the control unit 30, this image data is binarized, for example. The image data is converted into data and stored in a frame memory (not shown). Further, the control unit 30 starts light emission from the laser light source unit 62 of the distance sensor 40 prior to the start of exposure of the substrate material 20.

  On the other hand, as shown in FIG. 7A, in the exposure apparatus 10, the moving stage 16 is on standby at the original position, and the substrate material 20 is fed onto the moving stage 16 by the carry-in transport means 22.

  In the exposure apparatus 10, when the substrate material 20 is placed on the moving stage 16, the substrate material 20 is sucked and held on the moving stage 16. Thereafter, as shown in FIGS. 7B and 8, the moving stage 16 is moved in the measurement direction (arrow Ym direction). Thereby, the substrate material 20 placed on the moving stage 16 passes through a position facing the distance sensor 40. At this time, in the control unit 30, the distance Dr to the upper surface (exposure surface) of the substrate material 20 is measured by the distance sensor 40.

  In the exposure apparatus 10, when the measurement movement of the moving stage 16 is completed (see FIG. 7C), the exposure movement is started. In this exposure movement, as shown in FIG. 7D, the moving stage 16 is moved in the arrow Ye direction. The control unit 30 generates a modulation signal for each pixel based on the image data stored in the frame memory, and outputs the generated modulation signal to each exposure of the exposure head unit 28 at a timing based on the exposure movement of the moving stage 16. Output to the head 34.

  At this time, the control unit 30 performs focus adjustment by controlling the autofocus unit 56 of each exposure head 34 based on the distance D measured by the distance sensor 40. Thereby, the exposure apparatus 10 can perform image exposure on the substrate material 20 with an appropriate focus.

  Further, in the exposure apparatus 10, when the exposure to the substrate material 20 is completed and the moving stage 16 returns to the original position (see FIG. 7E), the substrate material 20 is discharged by the discharge conveyance unit 24, and the next When the substrate material 20 is placed on the moving stage 16 (see FIG. 7A), image exposure on the substrate material 20 is started.

By the way, in order to form a high-definition exposure image on the substrate material 20, accurate focus adjustment is necessary. For this purpose, the distance Dr needs to be accurately measured by the distance sensor 40. Such a distance sensor 40 has a narrow range width, a limited measurement range, and a hold function, so that the distance Dr is an appropriate distance D for the substrate material 20 out of the measurement range. Is difficult to output.
Here, the control unit 30 provided in the exposure apparatus 10 controls the distance sensor 40 in accordance with the exposure processing of the substrate material 20, and this distance sensor is used in the exposure apparatus 10 with reference to FIGS. 8 to 10. The control when 40 is used will be described.

  FIG. 8 shows an example of the control (distance measurement control) of the distance sensor 40 executed by the control unit 30. This flowchart is executed when, for example, the power switch of the exposure apparatus 10 is turned on to enable scanning exposure to the substrate material 20, or when the start-up of the apparatus for performing scanning exposure is started, exposure is performed. The process is terminated when the power switch of the apparatus 10 is turned off or when the scanning exposure to the substrate material 20 is terminated or interrupted (for example, in a standby state of the exposure apparatus 10).

  In the flowchart of FIG. 8, the operation of the distance sensor 40 is started in the first step 100. At this time, the laser light source unit 62 starts to emit light (step 102). That is, as shown in FIG. 9, prior to the substrate material 20 facing the distance sensor 40, the distance sensor 40 is turned on and light emission of the laser light source unit 62 is started.

Further, when the distance sensor 40 is turned on, the distance D is output from the distance calculation unit 66. At this time, as shown in FIG. 10 (A), the distance sensor 40 does not hold the measured value and the substrate material 20 is not opposed, so the distance D is the maximum distance. (D ₀ + α) is output.

  When the substrate material 20 is placed and held on the moving stage 16, the control unit 30 starts moving the moving stage 16 in the measurement direction. Thereby, the upper surface of the moving stage 16 and the upper surface of the substrate material 20 on the moving stage 16 are opposed to the distance sensor 40 in this order.

  Here, in the flowchart of FIG. 8, it is confirmed whether or not it is time to measure the distance D by the distance sensor 40 in step 104, and the timing at which the tip of the substrate material 20 is opposed to the distance sensor 40 is step 104. The determination is affirmative and the routine proceeds to step 106 where reading of the distance D output from the distance sensor 40 is started.

As shown in FIGS. 9 and 10A, in the distance sensor 40, the distance Ds to the upper surface of the moving stage 16 is out of the measurement range. Accordingly, the distance sensor 40 outputs the distance (D ₀ + α) as the distance D even if the relative position with respect to the moving stage 16 passes the positions Y ₀ and Y ₁ .

Thereafter, the relative position of the distance sensor 40 for the movable stage 16 has reached the position Y _2, and the distance Dr is the effective range within a distance D which is output from the distance sensor 40, distance Dr (e.g., the distance D ₁ , (D ₀ −α) <D ₁ <(D ₀ + α)).

Further, while the substrate material 20 is opposed to the distance sensor 40, the distance sensor 40 outputs a distance D (D = D ₁ ) corresponding to the distance Dr to the surface of the opposed substrate material 20. The distance D is read into the control unit 30.

In the flowchart of FIG. 8, it is confirmed in step 108 whether or not the substrate material 20 has passed the position facing the distance sensor 40 and it is time to end the distance measurement, and the rear end of the substrate material 20 is the distance sensor 40. Is passed (for example, the position Y _{3 in} FIG. 9), an affirmative determination is made in step 108, the process proceeds to step 110, and the reading of the distance D is terminated. When the reading of the distance D is completed, the control unit 30 creates data for adjusting the focal length FD of the exposure head 34 based on the read distance D.

As shown in FIGS. 9 and FIG. 10 (A), the in distance sensor 40, until the relative position with respect to the moving stage 16 reaches the position Y _3, if the distance Dr is within the measurement range, the distance Dr is a distance D Is output.

In contrast, the relative position of the distance sensor 40 for the movable stage 16, past the position Y ₃ corresponding to the end portion of the substrate material 20, the distance Dr increases sharply, which is measured by the distance sensor 40 (distance Ds , Ds> (D ₀ + α)). Thereby, the distance D (measurement value) output from the distance sensor 40 is held. In the distance sensor 40, when the measurement value is held, the output distance D is within the effective range. That is, the distance Dr of the substrate material 20 corresponding to the position _{Y 3} is When it is _{D 1,} the output of the distance sensor 40 is held in this distance _{D 1.}

  On the other hand, in the flowchart of FIG. 8, it is confirmed in step 112 whether or not the exposure to the substrate material 20 has been started. When the substrate stage 20 reaches a predetermined position with respect to the exposure head unit 28 when the movable stage 16 that has finished the measurement movement starts scanning movement, the control unit 30 exposes the light beam emitted from the light source unit 26. Along with sending to each exposure head 34 of the head unit 28, a modulation signal generated based on the image data is outputted to each exposure head 34.

  Thereby, the scanning exposure to the substrate material 20 is started. Further, when the substrate material 20 passes a position facing the exposure head unit 28, the control unit 30 ends the scanning exposure on the substrate material 20.

  Here, when scanning exposure to the substrate material 20 is started, an affirmative determination is made in step 112 and the routine proceeds to step 114. In step 114, the laser light source 62 of the distance sensor 40 is turned off. That is, the light emission of the laser light source unit 62 is stopped.

  In step 116, it is confirmed whether or not the scanning exposure is completed. When the scanning exposure is completed, an affirmative determination is made in step 116 and the process proceeds to step 118. In this step 118, the light emission of the laser light source 62 is resumed prior to the distance measurement for the next substrate material 20.

  In step 120, it is confirmed whether or not the exposure process (scanning exposure) in the exposure apparatus 10 is continued. When the exposure process is continued, an affirmative determination is made in step 120 and the process proceeds to step 104 to complete the exposure process. When the determination is made, a negative determination is made at step 120 and the routine proceeds to step 122 where the distance sensor 40 is turned off (the laser light source 62 is also turned off). Here, it is confirmed whether or not the exposure process is terminated after the light emission of the laser light source unit 62 is started. However, whether or not the exposure process is continued prior to the start of the light emission of the laser light source unit 62. It may be a thing to confirm.

  As shown in FIG. 10A, in the distance sensor 40, when the laser light source unit 62 stops emitting light (off), the laser beam is not received by the light receiving unit 64, and the hold setting unit 70 holds the distance D. Cancel (turn off). Further, when the scanning exposure is completed, the distance sensor 40 starts light emission of the laser light source unit 62 (ON).

In the distance sensor 40, the hold of the distance D is released by releasing the hold. Further, since the laser light source unit 62 stops emitting light, the distance calculation unit 66 outputs the maximum value (D ₀ + α) within the measurement range as the distance D. Further, the distance sensor 40 is kept in the hold release state even when the light emission of the laser light source unit 62 is started.

As a result, the substrate material 20 then reaches a position facing the distance sensor 40, and the distance Dr of the substrate material 20 is within the effective range of the distance sensor 40 (for example, D ₂ , (D ₀ −α) <D ₂ < If it is (D ₀ + α)), the distance sensor 40 outputs the distance Dr as a distance D (D = D ₂ ).

  At this time, the light emission stop of the laser light source unit 62 is a relatively short time during exposure, and there is sufficient time until the distance measurement for the next substrate material 20 is started. The laser beam is stable and accurate distance measurement is possible.

On the other hand, as shown in FIG. 10B, if the distance sensor 40 is not released from the hold, the distance D within the effective range is continuously output as shown by a two-dot chain line in FIG. 10B. The Thereby, even if the distance Dr of the substrate material 20 to be measured next is out of the effective range, the distance D within the effective range (here, D = D ₁ ) is read into the control unit 30. Since the read distance D is within the effective range, the control unit 30 adjusts the focus of the light beam based on the distance D.

  Therefore, a so-called focus shift occurs in the light beam applied to the substrate material 20 from the exposure head 34, and the quality of the exposure image formed on the substrate material 20 is degraded.

On the other hand, as shown in FIG. 10A, when the distance D of the substrate material 20 to be measured next is out of the effective range by holding off the distance sensor 40 in advance, As indicated by a two-dot chain line in FIG. 10 (A), even if the substrate material 20 passes, the distance sensor 40 outputs a distance D (D = D ₀ + α here) outside the effective range.

  Thereby, in the control unit 30, even if the substrate material 20 passes, the distance D within the effective range is not output from the distance sensor 40, so the distance Dr of the substrate material 20 is out of the effective range of the distance sensor 40. Can be recognized accurately. Therefore, it is possible to surely prevent the substrate material 20 from being exposed to an image in which the light beam is out of focus.

  Since the exposure apparatus 10 includes the stage height adjustment unit 68, the control unit 30 adjusts the height of the moving stage 16 by the stage height adjustment unit 68 when the appropriate distance Dr is not detected. Alternatively, the distance measurement of the substrate material 20 is performed again, and when the distance D within the effective range is obtained, the image exposure to the substrate material 20 may be performed based on the distance D at this time. .

  In the present embodiment, when the substrate material 20 is subjected to the exposure process, the light emission of the laser light source unit 62 is stopped. However, the timing and time of the light emission stop of the laser light source unit 62 are not limited to this. It is not limited.

  The light emission stop timing of the laser light source 62 can be any timing as long as the distance measurement of the substrate material 20 is completed and the distance measurement of the next substrate material 20 is started. At this time, it is preferable that the timing and time at which the laser light is stabilized after the laser light source unit 62 starts to emit light until the distance measurement of the substrate material 20 is performed. The light emission stop of the laser light source unit 62 (hold release in the hold setting unit 70) is performed from the time when it is possible to clearly determine that the distance measurement has been completed until the exposure of the substrate material 20 is completed. Is more preferable.

  On the other hand, in the present embodiment, the distance sensor 40 that releases the hold of the distance D by stopping the light emission of the laser light source unit 62 is used, but the release of the hold is not limited to this.

  For example, the distance sensor may be configured such that the hold setting unit 70 is connected to the control unit 30 and the hold setting unit 70 can release the hold of the distance D by a hold release signal of the control unit 30. At this time, the control unit 30 sends the hold release signal to the hold setting unit of the distance sensor at an arbitrary timing after the distance measurement of the substrate material 20 is finished and before the distance measurement for the next substrate material 20 is started. 70 may be entered. Thereby, it is possible to prevent erroneous detection of the distance Dr with respect to the substrate material 20 without stopping the light emission of the laser light source unit 62.

  In addition, when the distance sensor 40 is configured to cancel the hold of the measurement value when the light receiving unit 64 stops receiving the laser beam, the laser light source unit 62 stops the light emission. Instead, a configuration in which a shutter mechanism is provided to block the laser light emitted from the laser light source unit 62 or to block the laser light received by the light receiving unit 64 can be applied.

  In addition, this Embodiment demonstrated above does not limit the structure of the distance sensor to which this invention is applied. In order to enable distance measurement with high accuracy, the present invention has a narrow range width and a limited measurement range, and maintains a distance within the previous effective range when the measurement distance changes rapidly. The present invention can be applied to a distance sensor having an arbitrary configuration provided with means.

  Further, in the present embodiment described above, the exposure apparatus 10 has been described as an example. However, the present invention is not limited to this, and the range width is narrow and the measurement range is narrow in order to enable distance measurement with high accuracy. Using a distance sensor with a holding means that holds the distance within the previous effective range when the measurement distance changes abruptly, the distance measurement of the exposure object is performed by relative movement between the distance sensor and the exposure object. The present invention can be applied to an exposure apparatus having an arbitrary configuration.

It is a schematic block diagram of the exposure apparatus applied to this Embodiment. It is a block diagram which shows schematic structure of exposure apparatus. It is a schematic perspective view of the principal part which shows an example of the arrangement | sequence of the exposure head with respect to board | substrate material. (A) And (B) is the schematic which shows an example of the optical system of an exposure head. It is a schematic block diagram of the distance sensor applied to this Embodiment. It is a diagram which shows the distance by which the distance sensor is output with respect to the actual distance. (A)-(B) is a schematic diagram showing movement of the moving stage, (A) is the original position before the start of movement, (B) is during distance measurement, (C) is at the end of distance measurement, (D ) Shows the scanning exposure time, and (E) shows the scanning exposure end time. It is a flowchart which shows an example of the measurement control using a distance sensor. It is the schematic which shows the relative position of the distance sensor with respect to the moving stage and board | substrate material at the time of distance measurement. (A) is a timing chart which shows control of the distance sensor which concerns on this Embodiment, (B) is a timing chart which shows an example when hold release is not performed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Exposure apparatus 12 Base 16 Moving stage (moving means)
18 Stage drive unit (moving means)
20 Substrate material (exposure target, measurement target)
26 Light source unit 28 Exposure head unit (exposure control means, distance measurement control means, adjustment control means, holding release means)
30 Control Unit 34 Exposure Head 40 Distance Sensor 56 Autofocus Unit (Focus Adjustment Unit)
62 Laser light source part 64 Light receiving part 66 Distance calculation part (holding means)
70 Hold setting section (holding means)

Claims (4)

In an exposure apparatus that adjusts the focal length according to the distance to the exposure target when performing exposure by irradiating a light beam while scanning the exposure target having the photosensitive layer formed on the surface of the support,
When the distance to the measurement target is within a predetermined range, the distance to the measurement target can be measured by receiving the reflected light of the laser light emitted from the light source and applied to the measurement target. And while the measurement value changes at the end of the measurement target and deviates from the measurement range, while holding the foremost measurement value in the predetermined range, while the measurement value exceeds the predetermined range, Using a distance sensor formed with holding means for continuing to hold the measurement value,
A distance measurement method for measuring a distance for adjusting the focal position with the exposure object as the measurement object,
Prior to the exposure object passing through the light irradiation position of the distance sensor, light emission from the light source is started,
When the exposure object passes the light irradiation position of the distance sensor, measure the distance to the exposure object,
Prior to the measurement of the distance to the next exposure target, the measurement value is released by the holding unit.
A distance measuring method characterized by this.   The distance sensor emits light from the light source prior to the measurement of the distance to the next exposure object when the holding of the measurement value by the holding unit is released by stopping the light emission of the light source. The distance measuring method according to claim 1, wherein the distance measuring method is stopped.   The distance measurement method according to claim 2, wherein holding release of the measurement value by stopping light emission of the light source is performed during exposure of the exposure target based on a measurement result of the distance sensor. An exposure head capable of irradiating an exposure target with a light beam as exposure light;
A focus adjusting means provided in the exposure head and capable of adjusting a focal position of the light beam;
A light source that emits laser light, a light receiving unit that receives laser light emitted from the light source and reflected by the exposure target, and a distance that is calculated and calculated from the laser light received by the light receiving unit to the surface of the exposure target A distance calculation unit that outputs a distance calculated when is within the preset effective range, and a distance within the previous effective range is output when the distance calculated by the distance calculation unit is outside the effective range A distance sensor including holding means for holding
Moving means for moving the exposure object relative to the exposure head and the processing sensor;
When the exposure object is moved while facing the exposure head by the moving means, the light beam emitted from the exposure head is controlled based on the image data of the image to be exposed to the exposure object to perform an exposure process. Exposure control means to perform,
Distance measurement control means for measuring a distance to the exposure object moved while being opposed to the distance sensor by the moving means prior to the exposure processing on the exposure object;
When the exposure process is performed on the exposure target, the distance measurement control unit operates the focus adjustment unit based on the distance measured by the distance sensor, so that the focal position of the light beam is the surface of the exposure target. Adjustment control means for adjusting so that
Holding that releases the holding of the distance output by the distance sensor by the holding means after the distance measuring means finishes measuring the distance by the distance sensor and ends image exposure to the exposure target. Release means,
An exposure apparatus comprising:

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