Position detection device, drawing device, and position detection method

Abstract

The position of the upper surface of the membrane is determined with high precision. [Solution] When the film position detection unit detects two or more peaks in the reflected light intensity distribution where the distance between peaks is greater than a predetermined interval, it selects the peak 781 of the uppermost peak 78 in the vertical direction among the two or more peaks as the selected peak, which is the peak of the peak corresponding to the film reflected light. The film position detection unit extracts the portion of the reflected light intensity distribution that falls within the extraction width B range, which is less than or equal to twice the inter-peak threshold, centered on the selected peak, as the film light intensity distribution. Based on the film light intensity distribution, the film position detection unit determines the vertical position of the upper surface of the film. This allows for accurate determination of the vertical position of the upper surface of the film.

Description

Technical Field

[0001] The present invention relates to a technique for detecting the position of the upper surface of a film provided on a substrate having a substrate and a light-transmissive film provided on the upper surface of the substrate.

Background Art

[0002] Conventionally, in the drawing of patterns on printed circuit boards, semiconductor substrates, etc. (hereinafter referred to as "substrates"), a drawing apparatus that directly draws a pattern by irradiating a photosensitive material formed on the substrate with modulated light and scanning the irradiated area of the light has been used.

[0003] In such a drawing apparatus, due to irregularities caused by existing patterns (for example, underlying patterns such as metal wires) formed in advance on the substrate, or deformation of the substrate, etc., the distance between the drawing head and the substrate surface may vary. Therefore, in this drawing apparatus, the position of the substrate surface is detected, and the focal position of the drawing head is adjusted based on the detection result.

[0004] For example, in the pattern drawing apparatus of Patent Document 1, a pre-reading unit is provided in front of the optical head unit that emits a drawing light beam toward the substrate (that is, on the front side in the relative movement direction of the optical head unit with respect to the substrate). The pre-reading unit is a mechanism that detects the position of the substrate surface in the drawing planned area where drawing is to be performed by the optical head prior to drawing. The pre-reading unit emits detection light toward the substrate to form a light spot on the substrate surface, and receives the reflected light from the light spot with a photodetector. Then, the position of the substrate surface is detected based on the received light intensity in the photodetector.

Prior Art Documents

Patent Documents

[0006] Incidentally, when a light-transmitting thin film is formed on the substrate surface, if the look-ahead unit of Patent Document 1 attempts to detect the position of the substrate surface, reflected light from both the light spot formed on the surface of the thin film and the light spot formed on the surface of the substrate located beneath the thin film will be incident on the photodetector. Therefore, if the position of the film surface is detected based on the light intensity received by the photodetector, there is a risk that it will deviate from the actual position of the film surface.

[0007] This invention has been made in view of the above problems, and aims to accurately determine the position of the upper surface of a film. [Means for solving the problem]

[0008] One aspect of the present invention is a position detection device for a substrate comprising a substrate and a translucent film provided on the upper surface of the substrate, wherein the device detects the position of the upper surface of the film, and comprises: a detection illumination optical system that forms a light spot of detection light on the substrate; a light receiving unit that receives the reflected light of the detection light reflected by the substrate and acquires the light intensity distribution of the reflected light; and a film position detection unit that extracts a film light intensity distribution corresponding to film reflected light, which is the reflected light of the detection light reflected by the upper surface of the film, from the light intensity distribution of the reflected light acquired by the light receiving unit, and determines the position of the upper surface of the film in the vertical direction based on the film light intensity distribution. When two or more peaks with a peak-to-peak distance greater than a predetermined interval are detected in the light intensity distribution of the reflected light, the film position detection unit selects the peak of the one peak corresponding to the uppermost peak in the vertical direction among the two or more peaks as the peak of the film reflected light, and extracts the portion of the light intensity distribution of the reflected light that is included in a predetermined width range of twice the predetermined interval or less, centered on the selected peak, as the film light intensity distribution.

[0009] Aspect 2 of the present invention is a position detection device of aspect 1, wherein the predetermined width is at least twice the diameter of the image of the light spot in the light receiving unit.

[0010] A third aspect of the present invention is a position detection device according to aspect 1 (or aspect 1 or 2), wherein the predetermined width is 2 times or less the value obtained by subtracting 0.5 times the diameter of the image of the light spot in the light-receiving section from the amount of displacement of the light-receiving position in the light-receiving section corresponding to the thickness of the film.

[0011] Aspect 4 of the present invention is a position detection device according to aspect 1 (which may be any one of aspects 1 to 3), wherein if there are multiple peaks in the single mountain portion, the film position detection unit selects the one peak with the maximum light intensity among the multiple peaks as the selected peak.

[0012] Aspect 5 of the present invention is a position detection device according to aspect 1 (which may be any one of aspects 1 to 4), wherein the film position detection unit performs noise reduction processing to remove light quantities below a predetermined threshold as noise from the light quantity distribution of the reflected light before determining the vertical position of the upper surface of the film. The threshold is set based on the light quantity at the selected peak.

[0013] Aspect 6 of the present invention is a position detection device according to Aspect 1 (which may be any one of Aspects 1 to 5), wherein the predetermined interval is set to be less than or equal to the amount of displacement of the light-receiving position in the light-receiving section corresponding to the thickness of the film.

[0014] Aspect 7 of the present invention is a drawing apparatus for drawing a pattern on a substrate by irradiating it with light, comprising: a stage for holding the substrate; a drawing head for irradiating the upper surface of the substrate held on the stage with modulated light; and a stage moving mechanism for moving the stage relative to the drawing head in a scanning direction parallel to the upper surface of the substrate. The drawing head comprises: an illumination optical system into which light emitted from a light source is incident; a light modulation unit for modulating the light guided by the illumination optical system; a projection optical system for guiding the light modulated by the light modulation unit to the substrate; and an autofocus mechanism for adjusting the focus position of the light emitted from the drawing head in accordance with the variation in the distance between the projection optical system and the substrate. The autofocus mechanism adjusts the focus position of the light emitted from the drawing head by displacing an optical element included in the projection optical system based on the position in the vertical direction of the upper surface of the film determined by any one of the position detection devices of aspects 1 to 6.

[0015] Aspect 8 of the present invention is a position detection method for a substrate comprising a substrate and a translucent film provided on the upper surface of the substrate, the method comprising: a) forming a light spot of detection light on the substrate; b) receiving the reflected light of the detection light reflected by the substrate and obtaining the light intensity distribution of the reflected light; and c) extracting a film light intensity distribution corresponding to film reflected light, which is the reflected light of the detection light reflected by the upper surface of the film, from the light intensity distribution of the reflected light, and determining the position of the upper surface of the film in the vertical direction based on the film light intensity distribution. When the light intensity distribution of the reflected light includes two or more peaks where the distance between peaks is greater than a predetermined interval, in step c), the peak of the one peak corresponding to the uppermost of the two or more peaks in the vertical direction is set as a selected peak which is the peak of the film reflected light, and the portion of the light intensity distribution of the reflected light that is included in a predetermined width range of twice or less the predetermined interval centered on the selected peak is extracted as the film light intensity distribution. [Effects of the Invention]

[0016] In this invention, the position of the upper surface of the film can be determined with high precision.

Brief Description of the Drawings

[0017] [Figure 1] It is a perspective view showing a drawing apparatus according to one embodiment. [Figure 2] It is a longitudinal sectional view of a substrate. [Figure 3] It is a side view showing a portion near the first head support portion and the second head support portion. [Figure 4] [[ID=十六]]It is a plan view showing a portion near the first head support portion and the second head support portion. [Figure 5] It is a side view of a drawing head. [Figure 6] It is a side view of a pre-reading unit. [Figure 7] It is a view showing the detection surface of a light receiving portion. [Figure 8] It is a view showing the configuration of a computer. [Figure 9] It is a block diagram showing the functions of a control unit. [Figure 10] It is a view showing an example of the flow of pattern drawing. [Figure 11] It is a view showing an example of the flow of film position detection. [Figure 12] It is a view showing an example of the light quantity distribution of reflected light. [Figure 13] It is a view showing an example of the light quantity distribution of reflected light. [Figure 14] It is a view showing an example of the light quantity distribution of reflected light.

Embodiments for Carrying Out the Invention

[0018] Figure 1 is a perspective view showing a drawing apparatus 1 according to one embodiment of the present invention. The drawing apparatus 1 is a direct drawing apparatus that draws a pattern by irradiating a photosensitive material on a substrate 9 with spatially modulated, substantially beam-shaped light and scanning the irradiated area of ​​the light on the substrate 9. In Figure 1, three mutually orthogonal directions are indicated by arrows as the X, Y, and Z directions. In the example shown in Figure 1, the X and Y directions are mutually perpendicular horizontal directions, and the Z direction is the vertical direction (i.e., up and down direction). The same applies to the other figures.

[0019] The substrate 9 is, for example, a substantially rectangular flat printed circuit board. Figure 2 is a longitudinal cross-sectional view of the substrate 9. As shown in Figure 2, the substrate 9 comprises a base material 93 and a film 95 provided on the upper surface 94 of the base material 93. The base material 93 is, for example, a substantially rectangular flat member formed from a composite material including glass and resin. For example, a circuit pattern is pre-drawn (i.e., formed) on the upper surface 94 of the base material 93. The film 95 is a relatively thin, translucent film. The film 95 is in direct contact with the upper surface 94 of the base material 93 and is supported from below by the base material 93. The type and shape of the substrate 9 can be varied in various ways.

[0020] The drawing device 1 shown in Figure 1 comprises a stage 21, a stage movement mechanism 22, an alignment unit 3, a drawing unit 4, a look-ahead unit 7, and a control unit 8. The control unit 8 controls the stage movement mechanism 22, the alignment unit 3, the drawing unit 4, and the look-ahead unit 7, etc. The drawing device 1 also comprises a first head support unit 61, a second head support unit 62, and a base 66.

[0021] Stage 21 is a substantially rectangular, flat member positioned below (i.e., on the (-Z) side) the alignment unit 3, drawing unit 4, and look-ahead unit 7. Stage 21 includes a substrate holding unit 25 that holds the horizontal substrate 9 from below. The substrate holding unit 25 is, for example, a vacuum chuck that holds the lower surface of the substrate 9 by suction. The substrate holding unit 25 may have a structure other than a vacuum chuck, for example, a mechanical chuck. The upper surface 91 of the substrate 9 placed on the substrate holding unit 25 (i.e., the upper surface 91 of the film 95 shown in Figure 2) is substantially perpendicular to the Z direction and substantially parallel to the X and Y directions.

[0022] The stage movement mechanism 22 is a movement mechanism that moves the stage 21 relative to the alignment unit 3 and the drawing unit 4 in a horizontal direction (i.e., a direction substantially parallel to the upper surface 91 of the substrate 9). The stage movement mechanism 22 is mounted on the upper surface of the base 66 and supported from below by the base 66. The base 66 is, for example, a substantially rectangular parallelepiped member in which the length in the Y direction is longer than the length in the X direction.

[0023] The stage movement mechanism 22 comprises a first movement mechanism 23 and a second movement mechanism 24. The second movement mechanism 24 supports the stage 21 from below and moves the stage 21 linearly in the X direction along the guide rail. The first movement mechanism 23 supports the second movement mechanism 24 from below and moves the stage 21 linearly in the Y direction along the guide rail together with the second movement mechanism 24. The drive source for the first movement mechanism 23 and the second movement mechanism 24 is, for example, a linear servo motor or a motor attached to a ball screw. The structure of the first movement mechanism 23 and the second movement mechanism 24 can be modified in various ways.

[0024] The drawing device 1 may be provided with a stage rotation mechanism that rotates the stage 21 around a rotation axis extending in the Z direction. The drawing device 1 may also be provided with a stage lifting mechanism that moves the stage 21 in the Z direction. For example, a servo motor can be used as the stage rotation mechanism. For example, a linear servo motor can be used as the stage lifting mechanism. The structures of the stage rotation mechanism and the stage lifting mechanism can be modified in various ways.

[0025] The first head support section 61 and the second head support section 62 are erected on the upper surface of the base 66. In the example shown in Figure 1, the first head support section 61 and the second head support section 62 are gate-shaped members (so-called gantry) that straddle the stage 21 and the stage moving mechanism 22, respectively. The first head support section 61 and the second head support section 62 are substantially the same shape and are arranged side by side in the Y direction. The second head support section 62 is located on the (+Y) side of the first head support section 61. In this embodiment, the first head support section 61 is fixed to the base 66. The second head support section 62 is also fixed to the base 66.

[0026] Figure 3 is a side view showing the area near the first head support portion 61 and the second head support portion 62. Figure 4 is a top view showing the area near the first head support portion 61 and the second head support portion 62.

[0027] As shown in Figures 1, 3, and 4, the alignment unit 3 comprises a plurality of imaging heads 31 (three in the example shown in Figure 1) arranged in the X direction. Each imaging head 31 is equipped with a digital camera having, for example, a CCD (Charged Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) as an image sensor. Each imaging head 31 is supported by a first head support 61 above the stage 21 and the stage moving mechanism 22. In the example shown in Figure 1, the three imaging heads 31 are mounted on the (-Y) side of the first head support 61.

[0028] Of the three imaging heads 31, for example, the central imaging head 31 is fixed to the first head support 61, while the other two imaging heads 31 are movable in the X direction on the first head support 61. This allows the distance between the imaging heads 31 in the X direction to be changed.

[0029] Each imaging head 31 is an imaging unit that images alignment marks (not shown) that are pre-provided on the upper surface 91 of the substrate 9. In the drawing apparatus 1, the position of the substrate 9 on the stage 21 is detected based on the image acquired by the imaging head 31 (i.e., the image of the alignment marks). Then, based on the detected position of the substrate 9, alignment of the substrate 9 is performed (i.e., correction of the relative position of the substrate 9 with respect to the first drawing head group 401 and the second drawing head group 402, which will be described later).

[0030] The drawing unit 4 includes a first drawing head group 401 supported by a first head support 61 and a second drawing head group 402 supported by a second head support 62. The first drawing head group 401 and the second drawing head group 402 each include a plurality of drawing heads 41. Each drawing head 41 irradiates modulated light onto the upper surface 91 of the substrate 9.

[0031] In the example shown in Figure 1, the first drawing head group 401 comprises four drawing heads 41 arranged substantially in a linear fashion and substantially parallel to the X direction. The second drawing head group 402 also comprises four drawing heads 41 arranged substantially in a linear fashion and substantially parallel to the X direction. The four drawing heads 41 of the first drawing head group 401 and the four drawing heads 41 of the second drawing head group 402 have substantially the same shape and substantially the same structure.

[0032] The four drawing heads 41 of the first drawing head group 401 are mounted on the (+Y) side of the first head support section 61 and supported by the first head support section 61 above the stage 21 and the stage movement mechanism 22. The four drawing heads 41 of the second drawing head group 402 are mounted on the (-Y) side of the second head support section 62 and supported by the second head support section 62 above the stage 21 and the stage movement mechanism 22. The second drawing head group 402 is adjacent to the first drawing head group 401 in the Y direction on the (+Y) side (i.e., positioned in close proximity or in contact with it) and faces the first drawing head group 401 in the Y direction.

[0033] The four drawing heads 41 of the first drawing head group 401 are arranged at approximately equal pitches with respect to the X direction. The four drawing heads 41 of the second drawing head group 402 are also arranged at approximately equal pitches with respect to the X direction.

[0034] The four drawing heads 41 of the second drawing head group 402 are positioned differently from the four drawing heads 41 of the first drawing head group 401 in the X direction. In other words, the eight drawing heads 41 of the drawing unit 4 are arranged in a staggered pattern. As a result, the second drawing head group 402 irradiates the upper surface 91 of the substrate 9 with modulated light at a different position in the X direction than the first drawing head group 401.

[0035] The number and arrangement of drawing heads 41 included in the first drawing head group 401, and the number and arrangement of drawing heads 41 included in the second drawing head group 402, can be varied. In addition, in the drawing unit 4, for example, multiple drawing heads 41 may be arranged in a substantially linear manner along the X direction and supported by a single support. Alternatively, the number of drawing heads 41 provided in the drawing unit 4 may be just one.

[0036] Figure 5 is a magnified side view of one of the drawing heads 41 of the first drawing head group 401, viewed from the (+X) side. In Figure 5, to facilitate understanding of the figure, the drawing head cover 416 of the drawing head 41 is shown in cross-section, and the internal structure of the drawing head cover 416 is shown with solid lines. The structures of the other drawing heads 41 of the first drawing head group 401 and each drawing head 41 of the second drawing head group 402 are substantially the same as those shown in Figure 5. In addition, a part of the first head support section 61 is also shown in Figure 5.

[0037] The drawing head 41 is attached to the (+Y) side of the first head support 61. Each drawing head 41 of the second drawing head group 402 is positioned opposite to the drawing head 41 shown in Figure 5 (i.e., its orientation in the Y direction is reversed) and is attached to the (-Y) side of the second head support 62 (see Figure 1). The upper parts of the drawing heads 41 of the first drawing head group 401 and the second drawing head group 402 protrude upward from the upper surfaces (i.e., the (+Z) side end faces) of the first head support 61 and the second head support 62.

[0038] The drawing head 41 comprises a light source unit 412, an illumination optical system 413, a light modulation unit 414, a projection optical system 415, and an autofocus mechanism 417. The light source unit 412, illumination optical system 413, light modulation unit 414, projection optical system 415, and autofocus mechanism 417 are housed inside the drawing head cover 416. In the example shown in Figure 5, the drawing head cover 416 is a roughly rectangular cylindrical member that extends linearly substantially parallel to the Z direction. Also in Figure 5, the projection optical system 415 is shown enclosed by a dashed line.

[0039] In the example shown in Figure 5, the light source unit 412 is an optical fiber that guides light emitted from a light source (not shown) into the drawing head cover 416. For example, an LED (Light Emitting Diode) or an LD (Laser Diode) can be used as the light source. Note that the light source may be a light source other than an LED or LD. The light source unit 412 is located below the drawing head 41 and emits light upwards.

[0040] An illumination optical system 413 is positioned approximately vertically above the light source unit 412. Light emitted from the light source unit 412 enters the illumination optical system 413. The illumination optical system 413 has multiple optical elements such as lenses arranged approximately in a straight line and approximately parallel in the vertical direction. The illumination optical system 413 guides the light emitted from the light source unit 412 upward and causes it to enter the light modulation unit 414 located at the upper end of the drawing head 41.

[0041] The light modulation unit 414 includes, for example, a light modulator such as a DMD (Digital Micro Mirror Device) or a GLV (Grating Light Valve) (a registered trademark of Silicon Light Machines (Sunnyvale, California)). This light modulator modulates (i.e., spatially modulates) the light from the light source guided by the illumination optical system 413 and directs it downward. Note that the light modulator may be something other than a DMD or GLV.

[0042] A projection optical system 415 is positioned approximately vertically below the light modulation unit 414. In Figure 5, the projection optical system 415 is shown enclosed by a dashed line. In the example shown in Figure 5, the light modulation unit 414 and the projection optical system 415 are positioned on the (+Y) side of the illumination optical system 413. The projection optical system 415 has multiple optical elements such as lenses arranged in a substantially straight line substantially parallel to each other in the vertical direction. The projection optical system 415 guides the light modulated by the light modulation unit 414 downwards. The light emitted from the lower end of the projection optical system 415 irradiates the upper surface 91 (see Figure 1) of the substrate 9 located below the drawing head 41.

[0043] The autofocus mechanism 417 is positioned, for example, near the lower end of the projection optical system 415. In Figure 5, for illustrative purposes, the autofocus mechanism 417 is depicted as being fixed to the drawing head cover 416, but the position of the autofocus mechanism 417 can be changed in various ways. The autofocus mechanism 417 may be fixed, for example, to the (+Y) side of the first head support 61.

[0044] The autofocus mechanism 417 is a movement mechanism that displaces the optical element 418 included in the projection optical system 415 in the vertical direction. The autofocus mechanism 417 is, for example, a linear servo motor or a motor attached to a ball screw. The optical element 418 is a so-called focusing lens. The autofocus mechanism 417 adjusts the focus position of the light emitted from the drawing head 41 to align with the upper surface 91 of the substrate 9 by displacing the optical element 418 in the vertical direction in accordance with the variation in the vertical distance between the projection optical system 415 and the substrate 9. The optical element 418 may be a single optical element or two or more optical elements.

[0045] In the drawing apparatus 1 shown in Figure 1, pattern drawing on the substrate 9 is performed using a so-called multi-pass method. Specifically, modulated light from multiple drawing heads 41 of the drawing unit 4 is irradiated onto the upper surface 91 of the substrate 9, while the first moving mechanism 23 of the stage moving mechanism 22 moves the substrate 9 in the Y direction, causing it to pass below the drawing heads 41. As a result, the irradiation area of ​​the light from the multiple drawing heads 41 is scanned on the substrate 9 in the Y direction, and drawing is performed on the substrate 9. Subsequently, the second moving mechanism 24 moves the substrate 9 in the X direction (for example, towards (-X)) by a predetermined distance in steps. In the following description, this predetermined distance will also be referred to as the "step length".

[0046] Then, the substrate 9 is moved in the Y direction by the first moving mechanism 23, and light is irradiated onto the substrate 9 from the drawing head 41 in parallel with this movement, thereby performing drawing on the substrate 9. In the drawing device 1, the irradiation of light onto the substrate 9 as it moves in the Y direction and the step movement of the substrate 9 in the X direction are performed alternately, thereby performing the drawing of a pattern on the substrate 9.

[0047] In the following description, the Y direction will also be referred to as the "main scanning direction" or "scanning direction," and the X direction will also be referred to as the "sub-scanning direction" or "width direction." The main scanning direction and the sub-scanning direction are directions that are approximately parallel to the upper surface 91 of the substrate 9. In the stage moving mechanism 22, the first moving mechanism 23 is a main scanning mechanism that moves the stage 21 relative to the drawing head 41 in the main scanning direction. The second moving mechanism 24 is a sub-scanning mechanism that moves the stage 21 relative to the drawing head 41 in the sub-scanning direction.

[0048] In addition, the drawing device 1 may perform drawing on the substrate 9 using a single-pass method (also called a one-pass method) in which the drawing of a pattern on the substrate 9 is completed by moving the substrate 9 relative to the drawing head 41 only once in the Y direction.

[0049] As shown in Figures 1, 3, and 4, the look-ahead unit 7 includes a plurality of unit pairs 72 arranged substantially in a substantially straight line substantially parallel to the X direction, on the (-Y) side of the three imaging heads 31 of the alignment unit 3. Each of the plurality of unit pairs 72 corresponds to a plurality of drawing heads 41. Each unit pair 72 is located in substantially the same position with respect to the X direction as the corresponding drawing head 41. In the example shown in Figure 4, the look-ahead unit 7 includes eight unit pairs 72 corresponding to the eight drawing heads 41 of the drawing unit 4. In the look-ahead unit 7, four unit pairs 72 corresponding to the four drawing heads 41 of the first drawing head group 401 and four unit pairs 72 corresponding to the four drawing heads 41 of the second drawing head group 402 are arranged alternately in the X direction.

[0050] Each unit pair 72 comprises two look-ahead units 71 adjacent to each other in the X direction. In each unit pair 72, the (-X) look-ahead unit 71 is located at approximately the same position in the X direction as the illumination position on the substrate 9 of the light emitted from the drawing head 41 corresponding to each unit pair 72. In addition, in each unit pair 72, the (+X) look-ahead unit 71 is spaced apart from the (-X) look-ahead unit 71 by the aforementioned step length in the (+X) direction.

[0051] In the example shown in Figure 4, the look-ahead unit 7 comprises 16 look-ahead units 71. The multiple look-ahead units 71 of the look-ahead unit 7 are supported by a unit support portion 73 that protrudes in the (-Y) direction from the (-Y) side surface of the first head support portion 61. The unit support portion 73 is a substantially strip-shaped member that extends substantially parallel to the X direction on the (-Y) side of the first head support portion 61. The positions of the multiple look-ahead units 71 of the look-ahead unit 7 in the Y and Z directions are substantially the same.

[0052] Figure 6 is a schematic side view showing the configuration of one look-ahead unit 71 of the look-ahead section 7. The structure of the other look-ahead units 71 of the look-ahead section 7 is substantially the same as that shown in Figure 6. Figure 6 also shows a longitudinal cross-section of the substrate 9. In Figure 6, the thickness of the film 95 on the substrate 9 is depicted larger than it actually is in order to facilitate understanding of the figure.

[0053] The look-ahead unit 71 is a mechanism that detects the position in the vertical direction of the upper surface 91 of the substrate 9 with respect to the area to be drawn by the corresponding drawing head 41 (i.e., the area on the substrate 9 where drawing is planned to be performed by the drawing head 41) prior to actual drawing. The look-ahead unit 71 emits detection light toward the substrate 9 to form a light spot on the substrate 9 and acquires the light intensity distribution of the reflected light from the light spot.

[0054] The look-ahead unit 71 includes an illumination unit 74 that emits detection light toward the substrate 9 and an observation unit 75 that receives reflected light from the substrate 9. The illumination unit 74 and the observation unit 75 are arranged opposite each other in the Y direction, for example. In the example shown in Figure 6, the observation unit 75 is located on the (-Y) side of the illumination unit 74. The arrangement of the illumination unit 74 and the observation unit 75 can be changed in various ways. For example, the observation unit 75 may be located on the (+Y) side of the illumination unit 74.

[0055] The illumination unit 74 comprises a detection light source 741 and a detection illumination optical system 742. The detection illumination optical system 742 comprises, for example, a plurality of optical elements such as lenses. In Figure 6, the plurality of optical elements of the detection illumination optical system 742 are shown enclosed by dashed lines. The detection light source 741 emits detection light. The detection light has a different wavelength from the light emitted from the drawing head 41 (i.e., drawing light) so as not to expose the photosensitive material on the substrate 9. The detection illumination optical system 742 focuses the detection light emitted from the detection light source 741 and guides it to the upper surface 91 of the substrate 9 (i.e., the upper surface 91 of the film 95), forming a light spot on the upper surface 91. The light spot is, for example, an approximately oval shape that is long in the X direction.

[0056] The observation unit 75 comprises an observation optical system 751 and a light receiving unit 752. The observation optical system 751 comprises, for example, multiple optical elements such as lenses. In Figure 6, the multiple optical elements of the observation optical system 751 are shown enclosed by dashed lines. The observation optical system 751 guides the reflected light of the detection light reflected from the substrate 9 to the light receiving unit 752. The light receiving unit 752 receives the reflected light guided by the observation optical system 751 on the detection surface 753 and obtains the light intensity distribution of the reflected light on the detection surface 753. The light receiving unit 752 is, for example, a line sensor in which multiple light receiving elements (i.e., pixels) such as a CMOS or CCD are arranged in a substantially linear shape.

[0057] Figure 7 shows the detection surface 753 of the light-receiving unit 752. In Figure 7, if we set up a Cartesian coordinate system where the arrangement direction of the multiple pixels 754 of the light-receiving unit 752 is the u-axis and the direction perpendicular to the u-axis is the v-axis, then the v-direction approximately coincides with the X-direction described above, and the u-direction corresponds to the Y-direction. In the example shown in Figure 7, each pixel 754 is a roughly rectangular shape that is long in the v-direction. In Figure 7, for illustrative purposes, the number of pixels 754 is drawn less than the actual number. In this embodiment, 512 pixels 754 arranged in a roughly straight line in the u-direction are provided on the detection surface 753. In the following description, the pixel numbers of the pixels 754 located furthest to the (-u) side and furthest to the (+u) side are set to "1" and "512", respectively, and the pixel numbers are assumed to increase as one moves towards the (+u) direction.

[0058] In Figure 7, the image of the light spot (hereinafter also referred to as the "light spot image 76") formed on the detection surface 753 by the reflected light of the detection light reflected from the upper surface 91 of the substrate 9 (i.e., the upper surface 91 of the film 95) is drawn with a solid line. The light spot image 76 is approximately oval in shape, with a major axis extending approximately parallel to the v direction. The minor axis of the light spot image 76 extends approximately parallel to the u direction. Note that the shape of the light spot image 76 can be changed in various ways.

[0059] In the look-ahead unit 71 shown in Figure 6, a portion of the detection light emitted from the illumination unit 74 toward the substrate 9 is not reflected by the upper surface 91 of the film 95, but passes through the film 95 and is reflected by the upper surface 94 of the substrate 93. The light spot formed on the upper surface 94 of the substrate 93 is located on the (-Z) and (-Y) side than the light spot formed on the upper surface 91 of the film 95. Therefore, the image of the light spot formed on the detection surface 753 of the light receiving unit 752 by the reflected light of the detection light reflected by the upper surface 94 of the substrate 93 (hereinafter also referred to as the "light spot image 77") is located on the (-u) side than the light spot image 76 (i.e., the light spot image corresponding to the upper surface 91 of the film 95), as shown in Figure 7. In Figure 7, the light spot image 76 is shown by a solid line, and the light spot image 77 is shown by a dashed line.

[0060] As described above, the pixel numbers of the multiple pixels 754 on the detection surface 753 increase as you move from the (-u) side to the (+u) side. Therefore, when the position of the light spot on the substrate 9 in the Z direction is displaced towards the (-Z) side, the pixel numbers of the pixels 754 that overlap with the light spot image formed on the detection surface 753 by the reflected light from the light spot decrease. Also, when the position of the light spot on the substrate 9 in the Z direction is displaced towards the (+Z) side, the pixel numbers of the pixels 754 that overlap with the light spot image formed on the detection surface 753 by the reflected light from the light spot increase.

[0061] The displacement of the light spot on the substrate 9 in the Z direction is directly proportional to the displacement of the light spot image on the detection surface 753 of the light receiving unit 752 in the u direction. Therefore, by detecting the position of the light spot image 76 on the detection surface 753, the position of the upper surface 91 of the substrate 9 (i.e., the upper surface 91 of the film 95) in the Z direction can be detected.

[0062] Figure 8 shows the configuration of computer 800, which functions as a control unit 8. Computer 800 has the configuration of a general computer system, including a CPU 81, a GPU 82, a ROM 83, a RAM 84, a fixed disk 85, a display 86, an input unit 87, a reader 88, a communication unit 89, and a bus 80. The CPU 81 performs various arithmetic operations. The GPU 82 performs various arithmetic operations related to image processing. The ROM 83 stores the basic program. The RAM 84 stores various information. The fixed disk 85 stores information. The display 86 is a display unit that displays various information such as images.

[0063] The input unit 87 includes a keyboard 87a and a mouse 87b that accept input from the operator. The reader 88 reads information from a computer-readable recording medium 881 such as an optical disk, magnetic disk, magneto-optical disk, or memory card. The display 86, keyboard 87a, mouse 87b, and reader 88 are connected to the bus 80 via an interface I / F. The communication unit 89 sends and receives signals to and from external devices of the computer 800. The bus 80 is a signal circuit that connects the CPU 81, GPU 82, ROM 83, RAM 84, fixed disk 85, display 86, input unit 87, reader 88, and communication unit 89.

[0064] In computer 800, program 882 is read in advance from recording medium 881 via reader 88 and stored in fixed disk 85. Program 882 may also be stored in fixed disk 85 via a network. The CPU 81 and GPU 82 perform arithmetic processing using RAM 84 and fixed disk 85 according to program 882. The CPU 81 and GPU 82 function as the arithmetic unit in computer 800. Other configurations that function as the arithmetic unit besides the CPU 81 and GPU 82 may also be employed.

[0065] Figure 9 is a block diagram showing the functions of the control unit 8 implemented by the computer 800 shown in Figure 8. Figure 9 also shows the components other than the control unit 8. The control unit 8 comprises a storage unit 801, an alignment unit 803, a drawing control unit 804, and a film position detection unit 805. The storage unit 801 is implemented by a RAM 84 and a fixed disk 85, etc. The storage unit 801 stores various information in advance, such as data for patterns to be drawn on the substrate 9 (i.e., drawing data). The alignment unit 803, the drawing control unit 804, and the film position detection unit 805 are implemented by a CPU 81, a GPU 82, a ROM 83, a RAM 84, a fixed disk 85, and their peripheral components.

[0066] Next, the drawing of patterns by the drawing device 1 will be explained with reference to Figure 10. Figure 10 is a diagram showing an example of the flow of drawing patterns on the substrate 9. When drawing on the substrate 9, first the substrate 9 is held on the substrate holding part 25 of the stage 21 shown in Figure 1, and the stage 21 is moved in the (+Y) direction by the first moving mechanism 23 of the stage moving mechanism 22.

[0067] Stage 21 passes beneath the multiple imaging heads 31 of the alignment unit 3, and the alignment marks on the substrate 9 on the stage 21, which is moving at a constant speed, are imaged by the imaging heads 31 (step S11). When step S11 is completed, stage 21 returns to the vicinity of the (-Y) side end of the first moving mechanism 23 and waits.

[0068] The image including the alignment marks acquired in step S11 (hereinafter also referred to as the "imaging image") is sent to the control unit 8 and stored in the storage unit 801 (see Figure 9). Then, the alignment unit 803 acquires the position of the substrate 9 on the stage 21 (i.e., the relative position of the substrate 9 with respect to the stage 21) based on the imaging image stored in the storage unit 801.

[0069] The alignment unit 803 determines the amount of deviation from the design position of the substrate 9 on the stage 21, and the amount of deviation from the design position of the substrate 9 relative to the drawing head 41. The alignment unit 803 also determines alignment information to correct the relative position of the substrate 9 with respect to the drawing head 41 to match the design position based on this deviation (step S12). This alignment information is, for example, information to correct the movement of the substrate 9 by the stage moving mechanism 22 when drawing a pattern on the substrate 9. Alternatively, this alignment information may be information to correct the drawing data of the pattern drawn on the substrate 9 to match the above deviation amount.

[0070] Once the acquisition of alignment information is complete, the drawing control unit 804 shown in Figure 9 drives the stage moving mechanism 22 and the multiple drawing heads 41 of the drawing unit 4 based on the drawing data stored in the memory unit 801 and the alignment information. This starts the movement of the stage 21 and substrate 9, which are in the standby position, in the (+Y) direction.

[0071] When a portion of the substrate 9 in the Y direction passes below the look-ahead unit 7, the (-X) side look-ahead unit 71 of the unit pairs 72 corresponding to each drawing head 41 acquires the light intensity distribution of the reflected light of the detection light reflected from that portion of the substrate 9 by the light receiving unit 752 and sends it to the film position detection unit 805 (see Figure 9) of the control unit 8. Based on this light intensity distribution, the film position detection unit 805 determines the Z-direction position of the upper surface 91 of the film 95 on the portion of the substrate 9 (hereinafter also referred to as the "film position"). Details of how the film position is acquired by the film position detection unit 805 will be described later. In the drawing device 1, the look-ahead unit 71 and the film position detection unit 805 constitute a position detection device 70 for detecting the film position.

[0072] As described above, the (-X) side look-ahead unit 71 of unit pair 72 is located at approximately the same position in the X direction as the irradiation position of the light emitted from the corresponding drawing head 41 on the substrate 9. In other words, the (-X) side look-ahead unit 71 of unit pair 72 is used to acquire the film position in the region where the light is to be irradiated by the corresponding drawing head 41, prior to the irradiation of the light by the corresponding drawing head 41 on the substrate 9 moving in the (+Y) direction.

[0073] The film position determined by the film position detection unit 805 is sent from the film position detection unit 805 to the drawing control unit 804. When the aforementioned portion of the substrate 9 in the Y direction passes below the drawing head 41, the drawing control unit 804 controls the autofocus mechanism 417 based on the film position to displace the optical element 418 of the projection optical system 415. As a result, the focus position of the light emitted from the drawing head 41 is adjusted to be located on the upper surface 91 of the film 95 in the Z direction, and light is emitted from the drawing head 41 toward the upper surface 91 of the substrate 9 to perform drawing.

[0074] In the drawing device 1, as the substrate 9 moves in the (+Y) direction, the following are continuously performed: acquisition of the light intensity distribution by the (-X) side look-ahead unit 71 of each unit pair 72, acquisition of the film position by the film position detection unit 805, adjustment of the focus position by the drawing control unit 804, and emission of light from the drawing head 41 (i.e., drawing on the substrate 9). As the (-Y) side edge of the substrate 9 passes below the multiple drawing heads 41, drawing on the multiple unit drawing regions on the substrate 9, each corresponding to the multiple drawing heads 41, is completed. The unit drawing region is a band-shaped region that extends substantially parallel to the Y direction over substantially the entire length of the substrate 9 in the Y direction. The multiple unit drawing regions are spaced apart from each other in the X direction.

[0075] Furthermore, in the drawing device 1, while the substrate 9 is moving in the (+Y) direction, the look-ahead unit 71 on the (+X) side of each unit pair 72 continuously acquires the light intensity distribution of the reflected detection light reflected from the substrate 9 and sends it to the film position detection unit 805. The film position detection unit 805 determines the film position (i.e., the position of the upper surface 91 of the film 95 in the Z direction) based on this light intensity distribution. The film position detection unit 805 determines the film position at the position in the X direction corresponding to the look-ahead unit 71 on the (+X) side of each unit pair 72 over approximately the entire length of the substrate 9 in the Y direction.

[0076] In the following explanation, the distribution of membrane positions in the Y direction, obtained based on the output from the look-ahead unit 71 on the (+X) side of the unit pair 72, is also referred to as the "membrane position distribution." The membrane position distribution is the distribution of membrane positions in the Y direction at positions separated by the step length described above from the center of the unit drawing area in the X direction. The membrane position detection unit 805 sends the membrane position distribution obtained using the look-ahead unit 71 on the (+X) side of each unit pair 72 to the storage unit 801. The storage unit 801 stores the membrane position distribution corresponding to each unit pair 72 (i.e., corresponding to each drawing head 41).

[0077] In the drawing apparatus 1, when the stage 21 passes below the multiple drawing heads 41 and stops near the (+Y) end of the first moving mechanism 23, the stage 21 and the substrate 9 are moved by the second moving mechanism 24 in the (-X) direction by the aforementioned step length. As a result, the irradiation position of the light emitted from each drawing head 41 on the substrate 9 is displaced relative to the substrate 9 in the (+X) direction by the step length, and is located at approximately the same position in the X direction as the region where the aforementioned film position distribution was obtained.

[0078] When the above step movement of stage 21 is completed, stage 21 and substrate 9 are moved in the (-Y) direction by the first movement mechanism 23. As substrate 9 passes below the multiple drawing heads 41, the drawing control unit 804 controls the autofocus mechanism 417 based on the above film position distribution and displaces the optical elements 418 of the projection optical system 415. As a result, the focus position of the light emitted from the drawing heads 41 is adjusted to be located on the upper surface 91 of the film 95 in the Z direction, and light is emitted from the drawing heads 41 toward the upper surface 91 of substrate 9 to perform drawing.

[0079] In the drawing device 1, while the substrate 9 is moving in the (-Y) direction, the drawing control unit 804 continuously adjusts the focus position, and the drawing head 41 continuously emits light (i.e., draws on the substrate 9). As the (+Y) side edge of the substrate 9 passes beneath the multiple drawing heads 41, drawing is completed on the substrate 9 for multiple unit drawing areas corresponding to each of the multiple drawing heads 41.

[0080] In the drawing device 1, when the stage 21 passes below the multiple drawing heads 41 and stops near the (-Y) end of the first moving mechanism 23, the stage 21 and the substrate 9 are moved by the second moving mechanism 24 in the (-X) direction by the aforementioned step length. In the drawing device 1, drawing on the substrate 9 moving in the (+Y) direction, step-movement of the substrate 9 in the (-X) direction, drawing on the substrate 9 moving in the (-Y) direction, and step-movement of the substrate 9 in the (-X) direction are repeated a predetermined number of times, thereby completing the drawing of a pattern over substantially the entire surface of the substrate 9 (step S13). In the actual drawing device 1, steps S11 to S13 are performed sequentially on multiple substrates 9 to draw patterns.

[0081] Next, the film position detection performed in step S13 by the position detection device 70 (i.e., the look-ahead unit 71 and the film position detection unit 805) will be explained with reference to Figure 11. Figure 11 is a diagram showing an example of the flow of film position detection. When the film position (i.e., the position of the upper surface 91 of the film 95 in the Z direction) is detected, first, detection light is emitted from the illumination unit 74 of the look-ahead unit 71 toward the substrate 9, and a light spot of detection light is formed on the substrate 9 (step S21). Then, the reflected light of the detection light reflected by the substrate 9 is received by the light receiving unit 752 of the observation unit 75, and the light intensity distribution on the detection surface 753 of the reflected light is acquired (step S22). The light intensity distribution acquired by the light receiving unit 752 is sent to the film position detection unit 805.

[0082] As described above, a portion of the detection light emitted from the illumination unit 74 toward the substrate 9 is reflected by the upper surface 91 of the film 95, and another portion of the detection light passes through the film 95 and is reflected by the upper surface 94 of the substrate 93. As a result, as shown in Figure 7, a light spot image 76 corresponding to the reflected light from the upper surface 91 of the film 95 and a light spot image 77 corresponding to the reflected light from the upper surface 94 of the substrate 93 are formed on the detection surface 753 of the light receiving unit 752.

[0083] Therefore, the light intensity distribution of the reflected light acquired by the light-receiving unit 752 includes a peak 79 corresponding to the light spot image 77 and a peak 78 corresponding to the light spot image 76, as shown in Figure 12. Peaks 78 and 79 are regions where the light intensity is significantly greater than that of the surrounding areas. In the following description, the position with the greatest light intensity in peak 78 will also be called "peak 781," and the position with the greatest light intensity in peak 79 will also be called "peak 791." In the example shown in Figure 12, peak 791 is located at pixel number 140, and peak 781 is located at pixel number 320.

[0084] In the film position detection unit 805, for example, in the light intensity distribution illustrated in Figure 12, the light intensity corresponding to adjacent pixel numbers is compared from smaller pixel numbers to larger pixel numbers, and the pixel number with the maximum light intensity is determined to be the pixel number corresponding to the peak. Specifically, if the pixel number is i (where i is an integer from 1 to 512), the light intensity corresponding to pixel number i is LQ i Therefore, LQ while increasing i sequentially from 1 i and LQ i+1 LQ was compared to LQ i-1 <LQ i And LQ i >LQ i+1 The resulting i is considered to be the pixel number corresponding to the peak.

[0085] In the light intensity distribution illustrated in Figure 12, peak 791 at peak 79 and peak 781 at peak 78 are detected by the film position detection unit 805. When two peaks are detected in the light intensity distribution in this way, the film position detection unit 805 determines the distance D1 in the horizontal axis direction between peak 781 and peak 791 (hereinafter also referred to as the "inter-peak distance"). As described above, in the example shown in Figure 12, peak 791 is located at pixel number 140 and peak 781 is located at pixel number 320, so the inter-peak distance D1 is 180 pixels.

[0086] Then, the peak-to-peak distance D1 is compared with a predetermined interval (hereinafter also called the "peak-to-peak threshold") that is set in advance and stored in the memory unit 801. The peak-to-peak threshold is, for example, 100 pixels. The peak-to-peak threshold is set to be less than or equal to the amount of shift Ds of the light-receiving position in the light-receiving unit 752 corresponding to the thickness of the film 95 in the Z direction (i.e., the distance in the u direction between the light spot image 76 and the light spot image 77 shown in Figure 7). The peak-to-peak threshold is also set to be greater than or equal to the diameter R1 in the u direction of the light spot image 76 on the detection surface 753 of the light-receiving unit 752 (i.e., the direction of the arrangement of the multiple pixels 754).

[0087] The amount of shift Ds of the light-receiving position may be measured in advance using a test substrate having substantially the same structure as the substrate 9, before drawing on the substrate 9, or it may be calculated in advance by optical simulation based on the thickness of the film 95. The thickness of the film 95 may be a value measured by a film thickness measuring device separate from the drawing device 1, for example. The film thickness measuring device may be incorporated into the drawing device 1. Alternatively, the thickness of the film 95 may be determined from a pre-prepared table that associates the type and material of the film 95 with the thickness of the film 95.

[0088] In the film position detection unit 805, if the distance between peaks D1 is greater than the threshold between peaks, it is determined that peaks 781 and 791 are two distinct peaks 78 and 79. Of these two peaks 78 and 79, the peak 78 that corresponds to the uppermost peak in the vertical direction (i.e., the one furthest to the (+Z) side) is selected as the peak corresponding to the reflected light of the detection light reflected from the upper surface 91 of the film 95 (hereinafter also referred to as "film reflected light"). Furthermore, the peak 781 of the selected peak 78 (hereinafter also referred to as "selected peak") is set as the selected peak corresponding to the film reflected light (i.e., corresponding to the light spot image 76) (step S23).

[0089] Furthermore, the peak corresponding to the uppermost side in the vertical direction is the peak located on the (+u) side on the detection surface 753, and is the peak with the largest pixel number. Therefore, in step S23, regardless of whether the light intensity at peak 781 or 791 is greater, peak 78 is selected as the peak corresponding to the film reflected light, regardless of the magnitude of the light intensity at peaks 781 and 791.

[0090] In the film position detection unit 805, the portion of the reflected light intensity distribution shown in Figure 12 that falls within a predetermined width B centered on the selected peak (i.e., the peak 781 of the peak 78 corresponding to the film reflected light) is extracted as the film light intensity distribution corresponding to the film reflected light. The predetermined width B is, for example, 40 pixels. Then, based on the film light intensity distribution enclosed by the dashed line in Figure 12, the position of the upper surface 91 of the film 95 in the Z direction is determined by a known method (step S24). In this embodiment, the film position detection unit 805 determines the centroid position of the film light intensity distribution, and the position of the upper surface 91 of the film 95 in the Z direction is determined from the pixel number of the centroid position (i.e., the position of the centroid in the u direction). In step S24, feature quantities of the film light intensity distribution other than the centroid may be determined, and the position of the upper surface 91 of the film 95 in the Z direction may be determined based on these feature quantities.

[0091] In the following description, the predetermined width B mentioned above will also be referred to as the "extraction width B". The extraction width B is less than or equal to twice the peak-to-peak threshold mentioned above. Preferably, the extraction width B is more than twice the diameter R1 in the u direction of the light spot image 76 on the detection surface 753 of the light receiving unit 752. This makes it easier for substantially the entire light spot image 76 to be included in the film light intensity distribution extracted in step S24. The diameter (i.e., minor axis) R1 of the light spot image 76 is, for example, about 10 pixels.

[0092] Furthermore, the extraction width B is preferably twice the value obtained by subtracting 0.5 times the diameter R1 (i.e., the minor axis) of the light spot image 76 from the amount of shift in the light receiving position at the light receiving section 752 corresponding to the thickness of the film 95 in the Z direction (see Figure 7). By setting the extraction width B to "(Ds-0.5R1)x2" or less, the inclusion of the light intensity distribution of other peaks 79 (i.e., the light intensity distribution caused by reflected light from the upper surface 94 of the substrate 93) in the film light intensity distribution extracted in step S24 is suppressed.

[0093] Furthermore, if the reflected light intensity distribution includes two or more peaks whose inter-peak distance is greater than the inter-peak threshold, then, in substantially the same manner as above, the peak of the peak corresponding to the uppermost peak in the vertical direction (i.e., the peak located furthest to the (+u) side) among those two or more peaks is selected as the selected peak corresponding to the film reflected light. Then, the portion of the light intensity distribution that falls within the extraction width B centered on the selected peak is extracted as the film light intensity distribution, and the position of the upper surface 91 of the film 95 in the Z direction is determined based on this film light intensity distribution.

[0094] On the other hand, as illustrated in Figure 13, if the distance D2 between the two peaks 782 and 783 is less than or equal to the aforementioned inter-peak threshold, the film position detection unit 805 determines that the two peaks 782 and 783 are included in one peak 78. In this way, if multiple peaks 782 and 783 exist in one peak 78 which is the selected peak, the film position detection unit 805 determines that the peak 782 with the maximum light intensity among the multiple peaks 782 and 783 is the selected peak. Then, in substantially the same manner as above, the portion of the reflected light intensity distribution that falls within the extraction width B range centered on the selected peak 782 is extracted as the film light intensity distribution, and the position of the upper surface 91 of the film 95 in the Z direction is determined based on this film light intensity distribution.

[0095] Furthermore, if the light intensity of peak 783 is greater than that of peak 782, peak 783 is designated as the selected peak. Similarly, if there are three or more peaks in a single peak 78, the peak with the highest light intensity among the three or more peaks is designated as the selected peak, regardless of the relative pixel numbers of each peak.

[0096] Furthermore, as illustrated in Figure 14, if the peak 784 of the selected peak 78 spans multiple pixel numbers (i.e., if the peak 78 takes its maximum value at multiple consecutive pixel numbers), for example, the maximum or minimum pixel number among those multiple pixel numbers may be designated as the pixel number corresponding to the selected peak. Alternatively, the central pixel number among those multiple pixel numbers may be designated as the pixel number corresponding to the selected peak.

[0097] In steps S23 to S24, the film position detection unit 805 may perform noise reduction processing to remove light amounts below a predetermined threshold (hereinafter also referred to as the "light intensity threshold") from the light intensity distribution of the reflected light as illustrated in Figure 12, etc., as noise. This suppresses the shift of the center of gravity due to the influence of noise when determining the center of gravity of the film light intensity distribution, and the center of gravity can be determined with high accuracy. As a result, the position of the upper surface 91 of the film 95 in the Z direction can be determined with high accuracy.

[0098] Preferably, the noise reduction process is performed after the determination of the selected peak in step S23. The light intensity threshold is determined based on the light intensity at the selected peak determined in step S23. For example, the light intensity threshold is obtained by multiplying the light intensity at the selected peak by a predetermined percentage of 10% or more and 40% or less. This makes it possible to reduce the portion of the peak containing the selected peak (i.e., the peak corresponding to the film reflected light) that is removed by the noise reduction process, even when the light intensity at the selected peak is relatively small and the difference with the noise light intensity is relatively small. Therefore, the position of the upper surface 91 of the film 95 in the Z direction can be determined with greater accuracy.

[0099] The noise reduction process described above can be performed in various ways, as long as it is performed before the position of the upper surface 91 of the film 95 in the Z direction is determined. For example, the noise reduction process may be performed before the selection of peaks corresponding to the film reflected light in step S23, between step S23 and the extraction of the film light intensity distribution in step S24, or between the extraction of the film light intensity distribution in step S24 and the detection of the position of the upper surface 91 of the film 95.

[0100] The above-mentioned light intensity threshold may be set in advance, for example, by using the above-mentioned test substrate and obtaining the light intensity distribution of the reflected light in advance using the light receiving unit 752, based on the selected peak in the light intensity distribution (i.e., the peak of the peak corresponding to the film-reflected light).

[0101] As described above, the position detection device 70 is a device for detecting the position of the upper surface 91 of a translucent film 95 on a substrate 9 which comprises a base material 93 and a translucent film 95 provided on the upper surface 94 of the base material 93. The position detection device 70 comprises a detection illumination optical system 742, a light receiving unit 752, and a film position detection unit 805. The detection illumination optical system 742 forms a light spot of detection light on the substrate 9. The light receiving unit 752 receives the reflected light of the detection light reflected by the substrate 9 and obtains the light intensity distribution of the reflected light. The film position detection unit 805 extracts the film light intensity distribution corresponding to the film reflected light, which is the reflected light of the detection light reflected by the upper surface 91 of the film 95, from the light intensity distribution of the reflected light obtained by the light receiving unit 752. Based on the film light intensity distribution, the film position detection unit 805 determines the vertical position of the upper surface 91 of the film 95.

[0102] When the film position detection unit 805 detects two or more peaks (peaks 78, 79 in the above example) in the reflected light intensity distribution where the distance between peaks is greater than a predetermined interval (i.e., the inter-peak threshold), it selects the peak of the uppermost peak in the vertical direction among the two or more peaks (peak 781 of peak 78 in the above example) as the peak of the peak corresponding to the film reflected light. The film position detection unit 805 extracts the portion of the reflected light intensity distribution that is included in a predetermined width (i.e., extraction width B) centered on the selected peak and not exceeding twice the inter-peak threshold, as the film light intensity distribution.

[0103] This makes it possible to suppress the inclusion of the light intensity distribution of reflected light reflected from the upper surface 94 of the substrate 93 in the film light intensity distribution. As a result, the vertical position of the upper surface 91 of the film 95 can be accurately determined based on the film light intensity distribution.

[0104] As described above, the extraction width B is preferably at least twice the diameter of the light spot image in the light receiving unit 752 (in the above example, the diameter R1 of the light spot image 76). This allows the selection peak corresponding to the film reflected light to be shifted from the center of the peak corresponding to the film reflected light, so that when the film light intensity distribution is extracted, most of the peak can be included in the film light intensity distribution. As a result, the vertical position of the upper surface 91 of the film 95 can be determined with even greater accuracy.

[0105] As described above, the extraction width B is preferably twice the value obtained by subtracting 0.5 times the diameter of the light spot image at the light receiving unit 752 (in the above example, the diameter R1 of the light spot image 76) from the amount of displacement Ds of the light receiving position at the light receiving unit 752 corresponding to the thickness of the film 95. This effectively suppresses the inclusion of the light intensity distribution of the reflected light reflected from the upper surface 94 of the substrate 93 (in the above example, the light intensity distribution of the peak portion 79 corresponding to the substrate reflected light) in the film light intensity distribution. As a result, the influence of the substrate reflected light is suppressed, and the vertical position of the upper surface 91 of the film 95 can be determined with even greater accuracy.

[0106] As described above, if multiple peaks 782 and 783 exist in a single mountain portion 78, it is preferable for the film position detection unit 805 to select one of the multiple peaks 782 and 783 that has the maximum light intensity (peak 782 in the above example) as the selected peak. This makes it possible to suitably extract the film light intensity distribution from the light intensity distribution of reflected light.

[0107] As described above, it is preferable that the film position detection unit 805 performs noise reduction processing to remove light amounts below a predetermined threshold (i.e., light intensity threshold) from the reflected light intensity distribution as noise, before determining the vertical position of the upper surface 91 of the film 95. Furthermore, it is preferable that the light intensity threshold is set based on the light intensity at the selected peak. This makes it possible to reduce the portion of the peak containing the selected peak (i.e., the peak corresponding to the film reflected light) that is removed by the noise reduction processing, even when the difference between the light intensity at the selected peak and the noise light intensity is relatively small. Therefore, the vertical position of the upper surface 91 of the film 95 can be determined with even greater accuracy.

[0108] As described above, it is preferable to set the inter-peak threshold to be less than or equal to the amount Ds of the shift in the light-receiving position at the light-receiving section 752, which corresponds to the thickness of the film 95. This allows the inter-peak threshold to be set appropriately, and as a result, it is possible to suitably suppress the inclusion of the light intensity distribution of reflected light reflected from the upper surface 94 of the substrate 93 in the film light intensity distribution.

[0109] As described above, the drawing device 1 is a device that draws a pattern on a substrate 9 by irradiating it with light. The drawing device 1 comprises a stage 21, a drawing head 41, and a stage moving mechanism 22. The stage 21 holds the substrate 9. The drawing head 41 irradiates modulated light onto the upper surface 91 of the substrate 9 held by the stage 21. The stage moving mechanism 22 moves the stage 21 relative to the drawing head 41 in a scanning direction parallel to the upper surface 91 of the substrate 9 (in the above example, the Y direction).

[0110] The drawing head 41 comprises an illumination optical system 413, a light modulation unit 414, a projection optical system 415, and an autofocus mechanism 417. Light emitted from a light source enters the illumination optical system 413. The light modulation unit 414 modulates the light guided by the illumination optical system 413. The projection optical system 415 guides the light modulated by the light modulation unit 414 to the substrate 9. The autofocus mechanism 417 adjusts the focus position of the light emitted from the drawing head 41 in accordance with the variation in the distance between the projection optical system 415 and the substrate 9. Based on the vertical position of the upper surface 91 of the film 95 determined by the position detection device 70 described above, the autofocus mechanism 417 displaces the optical elements 418 included in the projection optical system 415 to adjust the focus position of the light emitted from the drawing head 41.

[0111] As described above, the position detection device 70 can accurately determine the vertical position of the upper surface 91 of the film 95. Therefore, the drawing device 1 can accurately draw patterns on the substrate 9.

[0112] The above-described position detection method comprises the steps of forming a light spot of detection light on the substrate 9 (step S21), receiving the reflected light of the detection light reflected by the substrate 9 and obtaining the light intensity distribution of the reflected light (step S22), and extracting the film light intensity distribution corresponding to the film reflected light, which is the reflected light of the detection light reflected by the upper surface 91 of the film 95, from the light intensity distribution of the reflected light, and determining the vertical position of the upper surface 91 of the film 95 based on the film light intensity distribution (steps S23-S24). When the light intensity distribution of the reflected light includes two or more peaks where the distance between peaks is greater than a predetermined interval (i.e., a peak-to-peak threshold), in steps S23-S24, the peak of the one peak corresponding to the uppermost peak in the vertical direction among the two or more peaks (in the above example, peak 781 of peak 78) is selected as the peak of the peak corresponding to the film reflected light. Then, the portion of the reflected light intensity distribution that falls within a predetermined width (i.e., extraction width B) centered on the selected peak and within a range of twice the inter-peak threshold is extracted as the film light intensity distribution.

[0113] This makes it possible to suppress the inclusion of the light intensity distribution of reflected light reflected from the upper surface 94 of the substrate 93 in the film light intensity distribution, similar to the above. As a result, the vertical position of the upper surface 91 of the film 95 can be accurately determined based on the film light intensity distribution.

[0114] Various modifications are possible to the position detection device 70, drawing device 1, and position detection method described above.

[0115] For example, the extraction width B may be less than twice the diameter R1 of the light spot image 76 in the light-receiving unit 752. Alternatively, the extraction width B may be greater than twice the value obtained by subtracting 0.5 times the diameter R1 of the light spot image 76 in the light-receiving unit 752 from the amount of shift Ds of the light-receiving position in the light-receiving unit 752 corresponding to the thickness of the film 95 (i.e., (Ds-0.5R1)x2).

[0116] In the above-described distribution of reflected light intensity, if multiple peaks exist in a single peak corresponding to the film-reflected light, the selected peak does not necessarily have to be the peak with the highest light intensity among those multiple peaks; it may be any other peak.

[0117] In the position detection device 70, the noise reduction process described above may be omitted.

[0118] The peak threshold may be set to be greater than the amount of shift Ds in the light-receiving position at the light-receiving unit 752, which corresponds to the thickness of the film 95.

[0119] The light-receiving unit 752 is not necessarily limited to a line sensor; for example, it may be an area sensor in which multiple pixels are arranged in a planar manner.

[0120] In the imaging apparatus 1, the stage 21 can be moved relative to the imaging head 31 and the imaging head 41 in the main scanning direction by the first moving mechanism 23. For example, the stage 21 may be fixed, and the imaging head 31 and the imaging head 41 may be moved in the main scanning direction by the first moving mechanism 23 above the stage 21. Similarly, the imaging head 31 and the imaging head 41 may be moved in the sub-scanning direction by the second moving mechanism 24.

[0121] Furthermore, in the drawing device 1, the acquisition of the film position by the position detection device 70 does not necessarily have to be performed at the timing described above, but can be performed at various timings, as long as it is performed prior to the irradiation of the region where the film position has been acquired with light by the drawing head 41.

[0122] The position detection device 70 may be used in devices other than the drawing device 1 to detect the position of the upper surface 91 of the film 95. For example, the position detection device 70 may be provided in a marking device that performs laser marking on an object, or in an inspection device that performs a predetermined inspection on an object.

[0123] The configurations in the above embodiments and each modified example may be combined as appropriate, as long as they do not contradict each other. [Explanation of Symbols]

[0124] 1 Drawing device 9 circuit boards 21 stages 22 Stage Movement Mechanism 41 drawing head 70 Position detection device 76 Light Spot Image 78,79 Yamabe 91 Top surface (of substrate and film) 93 Base material 94 Top surface (of the substrate) 95 membrane 413 Illumination optical system 414 Optical Modulation Section 415 Projection optical system 417 Autofocus mechanism 418 Optical elements 742 Detection and illumination optics 752 Light receiving part 781,782,783,784,791 Peak 805 Membrane position detection unit B Extraction width Distance between peaks D1 and D2 Ds displacement R1 diameter S11-S13, S21-S24 Step

Claims

1. A position detection device for a substrate comprising a base material and a translucent film provided on the upper surface of the base material, wherein the position of the upper surface of the film is detected, A detection illumination optical system that forms a light spot of detection light on the substrate, A light receiving unit that receives the reflected light of the detection light reflected by the substrate and obtains the light intensity distribution of the reflected light, A film position detection unit extracts a film light intensity distribution corresponding to the film reflected light, which is the reflected light of the detection light reflected from the upper surface of the film, from the light intensity distribution of the reflected light acquired by the light receiving unit, and determines the vertical position of the upper surface of the film based on the film light intensity distribution. Equipped with, The film position detection unit, when detecting two or more peaks in the reflected light intensity distribution where the distance between peaks is greater than a predetermined interval, selects the peak of the uppermost peak among the two or more peaks in the vertical direction as the selected peak, which is the peak of the peak corresponding to the reflected light of the film, and extracts the portion of the reflected light intensity distribution that is included in a predetermined width of twice the predetermined interval or less, centered on the selected peak, as the film light intensity distribution.

2. A position detection device according to claim 1, A position detection device in which the predetermined width is at least twice the diameter of the image of the light spot in the light receiving unit.

3. A position detection device according to claim 1, A position detection device in which the predetermined width is less than or equal to twice the value obtained by subtracting 0.5 times the diameter of the image of the light spot in the light-receiving part from the amount of displacement of the light-receiving position in the light-receiving part corresponding to the thickness of the film.

4. A position detection device according to claim 1, If multiple peaks exist in the aforementioned single mountain portion, the film position detection unit selects the one peak with the maximum light intensity among the multiple peaks as the selected peak.

5. A position detection device according to claim 1, Before determining the vertical position of the upper surface of the film, the film position detection unit performs noise reduction processing to remove light quantities below a predetermined threshold from the light quantity distribution of the reflected light as noise. The threshold is set based on the amount of light at the selected peak in the position detection device.

6. A position detection device according to claim 1, A position detection device in which the predetermined interval is set to be less than or equal to the amount of displacement of the light-receiving position in the light-receiving section corresponding to the thickness of the film.

7. A drawing device that draws patterns on a substrate by irradiating it with light, A stage for holding the substrate, A drawing head that irradiates modulated light onto the upper surface of the substrate held on the stage, A stage movement mechanism that moves the stage relative to the drawing head in a scanning direction parallel to the upper surface of the substrate, Equipped with, The aforementioned drawing head is An illumination optical system into which light emitted from a light source is incident, A light modulation unit that modulates the light guided by the illumination optical system, A projection optical system that guides the light modulated by the aforementioned optical modulation unit to the substrate, An autofocus mechanism that adjusts the focus position of the light emitted from the drawing head in accordance with the variation in the distance between the projection optical system and the substrate, Equipped with, The autofocus mechanism adjusts the focus position of the light emitted from the drawing head by displacing an optical element included in the projection optical system based on the position in the vertical direction of the upper surface of the film determined by the position detection device according to any one of claims 1 to 6.

8. A position detection method for a substrate comprising a base material and a translucent film provided on the upper surface of the base material, wherein the position of the upper surface of the film is detected. a) A step of forming a light spot of detection light on the substrate, b) A step of receiving the reflected light of the detection light reflected by the substrate and obtaining the light intensity distribution of the reflected light, c) A step of extracting a film light intensity distribution from the light intensity distribution of the reflected light, which is the film reflected light that is the reflected light of the detection light reflected from the upper surface of the film, and determining the position of the upper surface of the film in the vertical direction based on the film light intensity distribution, Equipped with, A position detection method in which, when the light intensity distribution of the reflected light includes two or more peaks where the distance between peaks is greater than a predetermined interval, in step c), the peak of the one peak corresponding to the uppermost of the two or more peaks in the vertical direction is selected as the peak of the peak corresponding to the film reflected light, and the portion of the light intensity distribution of the reflected light that is included in a predetermined width of twice or less the predetermined interval centered on the selected peak is extracted as the film light intensity distribution.

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