JP5414281B2 - Exposure apparatus and exposure method - Google Patents

Description

  The present invention relates to a technique for improving exposure resolution by reducing the size of the minimum pitch that can be controlled in a technique for drawing (exposure) a pattern such as a circuit diagram by a beam.

  For example, in a process of manufacturing a glass substrate of a liquid crystal display, an exposure apparatus is used that exposes a pattern (circuit pattern or the like) by irradiating a beam from the exposure head while scanning the substrate surface (image surface) with the exposure head. . At this time, if the exposure apparatus includes only one exposure head that irradiates a single beam, the scanning pitch of the exposure apparatus becomes the beam pitch of the exposure apparatus.

  FIG. 21 is a diagram conceptually showing the image data 100 when the pattern is exposed. FIG. 21 shows the beam diameter (0.33 μm), beam pitch (0.1 μm), and exposure pixel 101 (beam pitch × beam pitch) when exposing the pattern. Is shown. The image data 100 is data in which a pixel value of “0” or “1” is recorded for each exposure pixel 101 in accordance with the pattern shape to be exposed. That is, the image data 100 is created as so-called binary bitmap data. In FIG. 21, a pixel value of “1” is recorded in the exposure pixel 101 indicated by a dark color, and a pixel value of “0” is recorded in the exposure pixel 101 indicated by white.

  FIG. 22 is a diagram showing a state in which a pattern is exposed according to the image data 100 shown in FIG. In the example shown here, the beam is turned on (irradiated state) for the exposure pixel 101 having the pixel value “1”, while the beam is applied to the exposure pixel 101 having the pixel value “0”. The pattern is exposed by turning it off (not illuminated). As a result, the exposure area 102 shown in dark color in FIG. 22 is exposed as a pattern.

  As is apparent from FIG. 22, when the pattern is exposed by switching the beam ON / OFF, the controllable exposure resolution (control pitch) is almost the beam pitch. Therefore, in order to improve the exposure resolution and accurately draw a finer pattern, it is required to reduce the beam pitch.

  However, since the size of the scanning pitch depends on the drive system, there is a problem that it is difficult to reduce the size. Further, when the scanning pitch and the beam diameter are reduced, the exposure width becomes narrow, so that the exposure speed is lowered.

  Therefore, conventionally, a technique has been proposed in which a plurality of exposure heads (multi-heads) are provided, and a plurality of beams irradiated from the respective exposure heads are imaged by an optical system. Further, by simultaneously exposing with a plurality of beams, it is possible to compensate for a decrease in exposure speed.

JP 2000-305276 A

  However, in any conventional technique, the exposure resolution is still dependent on the beam pitch. Therefore, in the example shown in FIGS. 21 and 22, when it is considered to improve the exposure resolution to 20 nm, it is necessary to design the beam pitch to 20 nm. However, since the beam pitch is limited by hardware mechanism, there is a problem that there is a limit to downsizing. In other words, the conventional technique has a problem that it is difficult to further improve the exposure resolution as compared with the beam pitch that is restricted by processing accuracy and the like.

  The present invention has been made in view of the above-described problems, and can be easily realized, and an object of the present invention is to expose a more precise pattern without reducing the exposure speed.

In order to solve the above problems, the invention of claim 1 is an exposure apparatus that exposes a pattern to an object with a beam irradiated at a predetermined beam pitch, and a light source that irradiates illumination light to be the beam; Based on multi-value data expressing the pattern by exposure pixels of a size corresponding to the predetermined beam pitch, a light amount control means for controlling the light amount of the beam, and a beam controlled by the light amount control means An exposure head that exposes the pattern at a control pitch smaller than the predetermined beam pitch while irradiating at the beam pitch, and pattern data representing the pattern by control pixels having a size corresponding to the control pitch. By detecting edge control pixels that are the control pixels that make up the edge, E Bei and data conversion means for generating a serial multivalued data, the data conversion unit detects the edge control pixel only for a predetermined direction from the position of the control pixels corresponding to the position of the optical axis of the beam.

Further, the invention of claim 2 is the exposure apparatus according to the invention of claim 1 , wherein the data conversion means includes the pattern in the pattern data and a pattern exposed by the beam according to the light amount of the beam. by performing matching, to create the multi-value data.

Further, the invention of claim 3, there is provided an exposure apparatus according to the invention of claim 1, wherein the data conversion means, to create the multi-level data with reference to a lookup table.

According to a fourth aspect of the present invention, there is provided the exposure apparatus according to any one of the first to third aspects, wherein a spatial light modulation unit that modulates illumination light from the light source into a plurality of beams by a plurality of micromirrors. further comprising, said light amount control means that controls the light amount of the plurality of beams individually.

The invention of claim 5 is an exposure method for exposing a pattern to an object with a beam irradiated at a predetermined beam pitch, and (a) irradiating illumination light to be the beam from a light source; b) controlling the light amount of the beam based on multi-value data expressing the pattern by exposure pixels of a size corresponding to the predetermined beam pitch; and (c) the beam controlled in the step (b). Exposing the pattern at a control pitch smaller than at least the predetermined beam pitch while irradiating the pattern from the exposure head at the predetermined beam pitch, and (d) the pattern by the control pixels having a size corresponding to the control pitch. By detecting an edge control pixel which is a control pixel constituting an edge of the pattern in the pattern data expressing the multi-value, Possess a step of creating a data, said step (d), step a is an exposure method for detecting the edge control pixel only for a predetermined direction from the position of the control pixels corresponding to the position of the optical axis of the beam.

The invention of claim 6 is the exposure method according to the invention of claim 5 , wherein the step (d) includes the pattern in the pattern data and a pattern exposed by the beam in accordance with the light amount of the beam. by performing matching with, Ru step der to create the multi-value data.

The invention of claim 7 is an exposure method according to the invention of claim 5, wherein step (d), Ru step der to create the multi-level data with reference to a lookup table.

An invention according to claim 8 is the exposure method according to any one of claims 5 to 7 , wherein (e) a plurality of micromirrors provided in the spatial light modulation means converts the illumination light from the light source into a plurality of further comprising the step of modulating the beam, the step (b), Ru step der to control the light quantity of the plurality of beams individually.

According to the first to eighth aspects of the present invention, the amount of light of the beam is controlled based on the multivalued data representing the pattern by the exposure pixel having a size corresponding to the predetermined beam pitch, and the beam thus controlled is controlled. By exposing the pattern with a control pitch smaller than the predetermined beam pitch while irradiating with the predetermined beam pitch, the control pitch smaller than the beam pitch becomes the exposure resolution, so the resolution depending on the size of the beam pitch The pattern can be exposed with excellent resolution.

Further, based on the pattern data representing the pattern by controlling the pixel size corresponding to the control pitch, by obtaining Bei data conversion means for generating multi-value data, only provide data corresponding to the exposure resolution exposure apparatus The pattern can be exposed.

Further, by detecting the edge control pixel is controlled pixels constituting the pattern of the edge in the pattern data, by creating a multi-level data can be easily realized inventions.

Further, by detecting the edge control pixel only for a predetermined direction from the position of the control pixels corresponding to position of the optical axis of the beam, it can be realized inventions with a simple configuration.

The invention according to claims 2 and 6 performs the pattern in the pattern data, the matching of the pattern to be exposed by the beam in accordance with the amount of the beam, by creating a multi-level data, according to claim 1 and The invention according to claim 5 can be easily realized.

The inventions according to claims 3 and 7 can easily realize the inventions according to claims 1 and 5 by creating multi-value data while referring to a lookup table.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

<1. First Embodiment>
FIG. 1 is a view showing an exposure apparatus 1 according to the first embodiment. In FIG. 1, for convenience of illustration and description, the Z-axis direction is defined as the vertical direction, and the XY plane is defined as the horizontal plane. However, these directions are defined for convenience in order to grasp the positional relationship, and do not limit each direction described below. The same applies to the following drawings.

  In the following description, “beam pitch” means an optical axis interval between adjacent beams (irrespective of irradiation at the same time or time-sequential irradiation) on the image plane. And The “control pitch” refers to the minimum controllable pitch when the exposure apparatus 1 controls geometric parameters such as the position and line width of the pattern to be exposed, and is a value indicating the exposure resolution. To do. For example, even if the minimum line width of the pattern to be exposed is 1 μm, if it is desired to control the line position and line width at 20 nm, the exposure resolution needs to be 20 nm.

  The exposure apparatus 1 includes a movable stage 10, an exposure head 11, and a control unit 2, and is configured as an apparatus that exposes a fine pattern (image) onto a substrate 9 supported on the movable stage 10. In addition, as the board | substrate 9, the glass substrate for printed boards, a liquid crystal display, the glass substrate for masks, a semiconductor substrate, etc. are assumed. However, the object on which the pattern is exposed is not limited to the substrate 9 shown here, and may be paper or a three-dimensional object. The exposure apparatus according to the present invention is not limited to a direct exposure apparatus that directly exposes a pattern with a beam, and may be a mask exposure apparatus or an apparatus in which an image to be exposed cannot be visually recognized (for example, development). It is not limited to a device that requires), and includes a so-called drawing device.

  The upper surface of the movable stage 10 is processed into a horizontal plane and has a function of holding the substrate 9 in a horizontal posture. The movable stage 10 performs suction from a suction port (not shown), thereby sucking the back surface of the placed substrate 9 and holding the substrate 9 in a predetermined position.

  The movable stage 10 has a structure that can move linearly in the X-axis direction and the Y-axis direction in accordance with a control signal from the control unit 2. That is, although not described in detail, the movable stage 10 includes a main scanning drive mechanism that moves the substrate 9 in the Y-axis direction and a sub-scanning drive mechanism that moves the substrate 9 in the X-axis direction. As such a mechanism, for example, a linear drive mechanism using a linear motor can be employed.

  Thereby, the exposure apparatus 1 can irradiate an arbitrary position on the surface of the substrate 9 with the beam irradiated from the exposure head 11. Thus, the beam irradiated from the exposure apparatus 1 is imaged with the surface of the substrate 9 as the image plane.

  The exposure head 11 modulates laser light guided by a laser oscillator 13 as a light source for irradiating laser light, an illumination optical system 14 that guides the laser light emitted from the laser oscillator 13 in a predetermined direction, and the illumination optical system 14. A spatial light modulation device 15 and an imaging optical system 16 for imaging the modulated laser light on the substrate 9 are provided.

  The laser oscillator 13 intermittently turns on a laser beam having a predetermined pulse width according to a reset signal transmitted from the control unit 2 at a cycle T (becomes a pulse laser). Thereby, the laser oscillator 13 in this Embodiment functions as a light source which irradiates a laser beam with the period T (predetermined period).

  In general, when the exposure interval is short, the movement of the movable stage 10 must be completed during the exposure interval. Therefore, it is necessary to move the movable stage 10 at a relatively high speed. On the other hand, if the exposure interval is long, the allowable time for completing the movement of the movable stage 10 becomes long, so that the movable stage 10 can be moved at a low speed. However, if the movable stage 10 is moved at a low speed, the time required to complete the exposure of the entire pattern becomes longer and the processing itself is delayed.

  Since the laser oscillator 13 in the present embodiment irradiates laser light at a constant exposure time (pulse width) and a constant exposure interval (period T) as described above, the moving speed of the movable stage 10 may be constant. . Therefore, the drive control becomes easy and it is possible to prevent the movement of the movable stage 10 from becoming unstable due to the speed change.

  In the exposure apparatus 1 in the present embodiment, an excimer laser is employed as the laser oscillator 13 that irradiates a pulse laser. The pulse width is about 10 [nsec] to several tens [nsec]. However, the laser beam used in the exposure apparatus 1 is not limited to such a laser beam.

  The illumination optical system 14 includes a mirror 140, a lens 141, and mirrors 142 and 143.

  Laser light emitted from the laser oscillator 13 and incident on the illumination optical system 14 is guided to the mirror 142 by the mirror 140 and the lens 141. The mirror 142 reflects the laser beam guided by the lens 141 toward the mirror 143, and the mirror 143 reflects the incident laser beam toward the spatial light modulation device 15. That is, the laser beam is adjusted by the mirror 142 and the mirror 143 so as to enter the spatial light modulation device 15 at a predetermined angle (incident angle).

  Thus, the illumination optical system 14 has a function of appropriately adjusting the optical path of the laser light emitted from the laser oscillator 13 and guiding it to the spatial light modulation device 15. Note that the configuration of the illumination optical system 14 is not limited to that shown in the present embodiment, and another optical element such as another lens or mirror may be appropriately disposed on the optical path of the laser light.

  The spatial light modulation device 15 on which the laser light guided by the illumination optical system 14 is incident has a structure in which N minute mirrors (N is a natural number of 2 or more) are arranged in a lattice shape on a silicon substrate. ing. In the following description, a micromirror included in the spatial light modulation device 15 is referred to as a “micromirror” and is distinguished from other mirrors (for example, the mirror 142).

  The laser light reflected by each micromirror of the spatial light modulation device 15 is directed to the imaging optics 16, where each forms a beam that can be used to expose the pattern. That is, the exposure apparatus 1 using the spatial light modulation device 15 has a structure in which N beams (multi-beams) are formed each time the laser oscillator 13 irradiates laser light. With such a structure, in the exposure apparatus 1 in the present embodiment, the interval between the micromirrors imaged on the exposure surface becomes the “beam pitch”.

  Although details will be described later, the exposure apparatus 1 does not necessarily irradiate the substrate 9 with all of the formed N beams. The present invention is not only applied to a multi-beam apparatus, but can also be applied to an apparatus that exposes a pattern with a single beam (an apparatus in which a scanning pitch is a beam pitch). Further, instead of a configuration that realizes a multi-beam by the spatial light modulation device 15, for example, an apparatus that realizes a multi-beam by providing a plurality of exposure heads 11 may be used.

  In the present embodiment, a micromirror device is employed as the spatial light modulation device 15.

The arrangement angle θ (angle formed by the reflection surface and the XZ plane) of the reflection surfaces of the plurality of micromirrors in the spatial light modulation device 15 is continuous between θ _on (first angle) and θ _off (second angle). It is possible to displace it. In the present embodiment, the arrangement angle θ of the reflection surface of each micromirror is θ _off during normal operation. Then, each micromirror of the spatial light modulation device 15 starts an operation of displacing the arrangement angle θ from θ _off to θ _on in accordance with the start signal transmitted from the control unit 2. In other words, the start signal is a signal indicating the timing for starting the switching of the state to the state in which the arrangement angle θ is θ _on with respect to the micromirror in the state in which the arrangement angle θ of the reflecting surface is θ _off. is there.

  The imaging optical system 16 includes an aperture 160, a mirror 161, and an imaging lens 162.

  The aperture 160 is configured as an optical element in which the amount of light of the beam changes depending on the position of the passing beam. The aperture 160 has a function of transmitting a part of the plurality of beams incident from the spatial light modulation device 15 and shielding a part thereof. The principle of individually adjusting the light amount of the beam by the aperture 160 will be described later.

  In addition, the aperture 160 has a function of adjusting a plurality of incident beams in directions parallel to each other (direction parallel to the Y-axis direction) and adjusting the spot shape of each beam to the same shape. Then, the beam that has passed through the aperture 160 is emitted toward the mirror 161.

  The beam emitted from the aperture 160 toward the mirror 161 is reflected by the mirror 161 and irradiated onto the surface of the substrate 9 that is an image plane through the imaging lens 162.

  As shown in FIG. 1, the control unit 2 mainly includes a CPU 20 and a storage device 21.

  The pattern data 210 is binary bitmap data representing a pattern to be exposed on the substrate 9. In general, data representing a pattern (pattern data 210 in the present embodiment) is created according to the exposure resolution of an apparatus that exposes the pattern, and is input to the apparatus. Therefore, the pattern data 210 is data expressed by dividing a pattern into pixels (hereinafter referred to as “control pixels”) having a size corresponding to the exposure resolution (control pitch) of the exposure apparatus 1. That is, the vertical and horizontal length sizes of the control pixels are each equal to the control pitch.

  The pattern data 210 is created by converting it into bitmap data by an external computer or the like based on data created by a CAD system or the like. The created pattern data 210 is acquired by the exposure apparatus 1 through data communication via a network and a communication unit (not shown) and stored in the storage device 21.

  The light amount data 211 is data created by the CPU 20 based on the pattern data 210, and is data in which the light amount of the beam irradiated on the substrate 9 for exposing the pattern is stored for each beam. Accordingly, the light quantity data 211 is multi-valued bitmap data expressed by dividing a pattern into pixels (hereinafter referred to as “exposure pixels”) having a vertical and horizontal length size equal to the beam pitch. Thereby, one exposure pixel corresponds to one beam and one micromirror. Note that “multi-value” here means more than two values.

  The CPU 20 operates based on a program (not shown) stored in the storage device 21, thereby executing various data calculations and generating control signals to control each component of the exposure apparatus 1. Have

  In particular, the CPU 20 in the present embodiment generates a reset signal with a period T and transmits it to the laser oscillator 13 so that the laser oscillator 13 emits laser light with the period T. Further, the position of the movable stage 10 is adjusted in order to adjust the relative position between the exposure head 11 and the substrate 9. Although details will be described later, the light quantity data 211 is created, and the spatial light modulation device 15 is controlled based on the created light quantity data 211.

  Although the storage device 21 is illustrated as if it is a piece of hardware in FIG. 1, in general, a read-only ROM, a RAM used as a temporary working area for the CPU 20, a relatively large capacity It is a device comprising a disk device or the like for storing data. The storage device 21 stores the above-described program and various data such as the pattern data 210 and the light amount data 211.

  FIG. 2 is a diagram showing functional blocks of the exposure apparatus 1 together with the data flow. The light quantity control unit 200 and the data conversion unit 201 illustrated in FIG. 2 are functional blocks realized by the CPU 20 of the control unit 2 operating according to the above-described program.

  The light quantity control unit 200 has a function of individually controlling the light quantity of each beam together with the aperture 160 by controlling the spatial light modulation device 15 based on the light quantity data 211. Note that “controlling the amount of light” is not the ON / OFF control of the beam (the light amount is controlled in a narrow sense), but between the light amount of the beam in the ON state and the light amount of the beam in the OFF state. A control mode in which an intermediate amount of light beam is also intentionally controlled and used for pattern exposure.

  FIG. 3 is a diagram illustrating an incident surface 163 formed on the surface of the aperture 160. A plurality of incident surfaces 163 are formed on the surface of the aperture 160 on the side facing the spatial light modulation device 15. Specifically, the surface of the aperture 160 on the side facing the spatial light modulation device 15 is divided into N incident surfaces 163. Each incident surface 163 is arranged so that only the beam from the corresponding micromirror is incident thereon. In the following description, the cross-sectional shape of the beam is described as “circular”, but the cross-sectional shape of the beam is not limited to a circular shape, and may be a rectangular shape.

In FIG. 3, the incident surface 163 _n−1 corresponding to the (n−1) th beam (the beam formed by the (n−1) th micromirror) and the nth beam (by the nth micromirror). The incident surface 163 _n corresponding to the formed beam) is shown. Note that n is a natural number satisfying 1 <n ≦ N.

  In addition, a light receiving area 164 is formed on each incident surface 163, and only the beam incident on the light receiving area 164 passes through the aperture 160 and is irradiated from the exposure head 11. In other words, among the beams incident on the incident surface 163, the beams incident on the region other than the light receiving region 164 are shielded by the aperture 160.

A circular region 80 shown in FIG. 3 indicates a region where a beam reflected by the micromirror is incident when the arrangement angle θ of the reflection surface of the nth micromirror is “θ _{on, n} ”. . That is, when the arrangement angle θ becomes “θ _on ”, the total luminous flux of the beam reflected by the micromirror is incident on the light receiving region 164 of the corresponding incident surface 163. Therefore, among the beams formed by the micromirror, the light amount of the beam irradiated on the substrate 9 is “100%”.

On the other hand, the circular area 81 shown in FIG. 3 is an area where the beam reflected by the micromirror is incident when the arrangement angle θ of the reflection surface of the nth micromirror is “θ _{off, n} ”. Indicates. That is, the total luminous flux of the beam reflected by the micromirror having the arrangement angle θ of “θ _off ” does not enter the light receiving region 164. Therefore, among the beams formed by the micromirror, the light amount of the beam irradiated on the substrate 9 is “0%”.

As described above, the arrangement angle θ of the reflection surface of the micromirror is continuously displaced between “θ _on ” and “θ _off ”. Therefore, for example, the region where the beam reflected by the nth micromirror can be incident becomes the region 82 shown in FIG. 3 (the region shaded with diagonal lines).

The circular region 83 shown in FIG. 3 is when the arrangement angle θ of the (n−1) -th micromirror is displaced between “θ _{on, n−1} ” and “θ _{off, n−1} ”. , Shows a region where the beam reflected by the micromirror is incident. In such a case, only a part of the reflected beam is incident on the light receiving region 164 and the other part is shielded. That is, only the laser beam incident on the region 84 (region shaded with diagonal lines) where the region 83 and the light receiving region 164 overlap is transmitted through the aperture 160, and the total amount of the reflected beam is received by the light amount of the beam. Compared with the case where the light enters the region 164, it is reduced by the amount shielded by the aperture 160.

That is, the light amount of the beam transmitted through the aperture 160 depends on the area of the region 84 that varies depending on the incident position of the beam, and the area depends on the arrangement angle θ of the micromirror. Conversely, when the desired amount of light beam formed by the n-th micromirror is "Omega _n", the arrangement angle theta _n of the micro-mirrors to obtain the light quantity Omega _n is a continuous function S _n This can be expressed as Formula 1.

θ _n = S _n (Ω _n ) Equation 1

Further, if the elapsed time after the control unit 2 gives the start signal to the n-th micromirror is “τ _n ”, the relationship between the arrangement angle θ _n and the elapsed time τ _n is an expression using the continuous function F _n. It is represented by 2.

τ _n = F _n (θ _n ) ... Equation 2

Therefore, it can be seen from Equations 1 and 2 that the elapsed time τ _n can be expressed as Equation 3 using a function Q _{n such} that Q _n = F _n (S _n ).

τ _n = Q _n (Ω _n ) ... Equation 3

Here, since the function Q _n is a reproducible function, it can be obtained in advance by experiments or the like and stored in the storage device of the exposure apparatus 1 as characteristic data. Incidentally, the function S _n and the function F _n keep in obtained by experiments, it may be calculated elapsed time tau _n by the operation by substituting equation 1 into equation 2.

  According to Equation 3, when the desired light amount “Ω” in the beam is determined, it can be determined at what timing the micromirror that forms the beam should be irradiated with the laser light after the start signal is given. .

  Since the laser oscillator 13 in the present embodiment irradiates the laser beam with the period T, all the micromirrors of the spatial light modulation device 15 are irradiated with the laser beam at the same time. That is, the timing at which each micromirror is irradiated with laser light is fixed in advance, and the structure is such that laser light cannot be irradiated at any time for each individual micromirror. Therefore, when the next laser light irradiation is performed, it is necessary to give a start signal to each micromirror in advance at an appropriate timing so that the arrangement angle θ of each micromirror becomes a desired angle.

Here, the time from the irradiation of the latest laser beam to the irradiation of the next laser beam is T. Therefore, if the elapsed time from when the latest laser beam is irradiated until the start signal is given to the n th micromirror is “t _n ”, the arrangement angle of the n th micro mirror is the desired arrangement angle θ _n . In order to irradiate the micromirror with the laser beam, the equation 4 needs to be satisfied.

t _n + τ _n = T Equation 4

Therefore, in order to set the light amount of the beam formed by the nth micromirror at the time of the next laser light irradiation to a desired light amount “Ω _n ”, the timing at which the start signal is given to the micromirror is the same as that of the previous laser light. It can be seen that using the elapsed time t _n after irradiation, it can be obtained by Equation 5.

t _n = T−Q _n (Ω _n ) Equation 5

  As described above, the light amount of the beam formed by the nth micromirror is indicated in the light amount data 211 as the light amount of the nth exposure pixel.

Therefore, the light quantity control unit 200 delays the reset signal that executed the previous laser light irradiation by the elapsed time t _n obtained for each micromirror based on the light quantity data 211 and Equation 5, and starts each of them. By transmitting these start signals to the spatial light modulation device 15 as signals, the light amount of the beam can be individually controlled.

  In addition, the structure for controlling the light quantity of the beam irradiated to the board | substrate 9 is not limited to the structure shown here, The various methods conventionally known can be used suitably. For example, instead of the aperture 160, an optical element whose amount of light changes depending on the position of light passing therethrough, such as a continuous density variable filter, may be used.

  Further, in the aperture 160, instead of dividing the surface facing the spatial light modulation device 15 into N incidence surfaces, only a single incidence surface is formed, and between the spatial light modulation device 15 and the aperture 160 is formed. The imaging lens 162 and a field lens that forms a telecentric optical system on both sides may be arranged so that each laser beam reflected from the micromirror transmits, shields, or partially transmits the single incident surface. .

  Further, as a configuration for controlling the amount of light, a diffraction grating type spatial light modulation element such as a GLV (Grating Light Valve) or a magneto-optical spatial light modulation element instead of the micromirror device as in the above embodiment. A configuration using may be used.

  Next, how the area exposed by the beam (hereinafter referred to as “exposure area”) changes when the light amount of the beam is changed will be described. In other words, how the exposure resolution is improved by controlling the light quantity of the beam will be described.

  FIG. 4 is a diagram showing a light amount distribution when the light amount of the beam is changed and an exposure area in each light amount beam. In the example shown in FIG. 4, the light amount distribution (graphs PF1, PF2, PF3, PF4, PF5, PF6) of each beam and exposure areas (six circles) exposed by the beam for six different light amounts. Show.

  The graph PF1 shows the light amount distribution of the beam with 100% light amount, the graph PF2 shows the light amount distribution of the beam with 85% light amount, and the gram PF3 shows the light amount distribution of the beam with 75% light amount. The graph PF4 shows the light amount distribution of the 65% light amount beam, the graph PF5 shows the light amount distribution of the 45% light amount beam, and the graph PF6 shows the light amount distribution of the 40% light amount beam. However, these numerical values are merely examples, and are not limited to the numerical values shown here, and can be obtained and stored experimentally as the characteristics of the beam used in the exposure apparatus 1.

  As shown in FIG. 4, a general light amount distribution of a beam is a distribution state that approximates a Gaussian distribution, where the light amount is larger at the central portion of the beam and the light amount is decreased at the peripheral portion. On the other hand, a photosensitive material (for example, a photoresist) is applied to the substrate 9, and a threshold value V (photosensitive threshold level) of the amount of light to be exposed is determined due to the properties of the photosensitive material. In other words, in the region irradiated with the beam, the region where the light amount exceeds “V” is exposed by the beam (becomes an exposure region), but the region where the light amount is less than “V” is not exposed.

  Therefore, even if the substrate 9 is actually irradiated with a beam having an actual beam diameter (in the example shown in FIG. 4, the size is about five times the beam pitch), the exposure region exposed by the beam is irradiated with the actual beam. It becomes a narrower area than the set area. In the example shown in FIG. 4, the exposure area when a beam having a light amount of 100% is irradiated is a circular area (the maximum circle in FIG. 4) whose diameter is the exposure beam diameter (three times the beam pitch) at that time. It has become.

  As can be seen from FIG. 4, although the actual beam diameter hardly changes even when the light quantity of the beam is changed, the exposure area changes as a concentric area having a different diameter (exposure beam diameter). As a result, an appropriate photosensitive material is selected as the threshold value V according to the light amount distribution of the beam, and the exposure beam diameter is changed at the desired exposure resolution by adjusting the light amount of the beam according to the desired exposure resolution. Can do.

  Therefore, according to such a principle, in the exposure apparatus 1, if the light amount control unit 200 appropriately controls the light amount of the beam, the exposure beam diameter of the beam can be controlled, and the exposure area exposed by the beam can be controlled. It can be seen that the size can be controlled.

  FIG. 4 shows an example in which the size of the exposure area is controlled at a pitch that is about one fifth of the beam pitch. In other words, in the example shown in FIG. 4, an example in which a fifth of the beam pitch is the minimum pitch (control pitch) that can be controlled by the exposure apparatus 1 is shown. As described above, according to the exposure apparatus 1 of the present embodiment, not the beam pitch but a pitch that is about a fraction of the beam pitch can be set as the “control pitch”.

  The exposure apparatus 1 obtains the relationship between the light amount of the beam and the exposure area developed on the photosensitive material (relationship shown in FIG. 4) in advance by experiment, theoretical simulation, or the like, and the beam characteristics in the exposure device 1. It is assumed that it is stored as data (not shown).

  As described above, the exposure apparatus 1 can reduce the control pitch without changing the beam pitch by controlling the light quantity of the beam, and can improve the exposure resolution. Further, unlike the technique of improving the exposure resolution by reducing the beam pitch, there is no problem of a reduction in exposure speed. Further, even if the amount of light is changed, the optical axis position of the beam hardly changes, and the position (center position) where the beam is irradiated does not change. That is, even if the light quantity of the beam is changed, no positional deviation occurs.

  In the present embodiment, the example in which the control is performed so that the size of one-fifth of the beam pitch becomes the control pitch has been described, but the control amount of the light amount is not limited to this. In the following description, the beam diameter is used to mean the exposure beam diameter unless otherwise specified.

  Returning to FIG. 2, the data conversion unit 201 creates light amount data 211 based on the pattern data 210 stored in the storage device 21 and the beam characteristic data (not shown) described above, and the storage device 21 has a function of storing.

  As described above, the pattern data 210 is binary bitmap data created in accordance with the control pixel of the exposure apparatus 1. On the other hand, the light quantity data 211 is multi-value bitmap data in which light quantity values are stored in accordance with the exposure pixels of the exposure apparatus 1. In other words, the data conversion unit 201 converts the high resolution bitmap data (pattern data 210) into relatively low resolution multi-value bitmap data (light amount data 211). Note that a method by which the data conversion unit 201 creates the light amount data 211 will be described later.

  The above is the description of the configuration and functions of the exposure apparatus 1 in the first embodiment.

  Next, a method in which the data conversion unit 201 creates the light amount data 211 will be described.

  FIG. 5 is a diagram showing the exposure pixel P. As shown in FIG. In the exposure apparatus 1 in the present embodiment, the vertical and horizontal size of the exposure pixel P is the beam pitch (0.1 μm), and the vertical and horizontal size of the control pixel Q is the control pitch (20 nm, one fifth of the beam pitch). . Therefore, one exposure pixel P is composed of 25 control pixels Q (control pixels Q00 to Q44).

  FIG. 6 is a diagram showing the unit region E. As shown in FIG. As already shown in FIG. 4, in the exposure apparatus 1, the beam diameter of the beam having the maximum light amount is three times the beam pitch. That is, paying attention to the exposure pixel P11 in FIG. 6, when the exposure pixel P11 is irradiated with a beam, a region that can be exposed by the beam is a circular region EE indicated by hatching in FIG.

  Therefore, the exposure pixels P00 to P22 can be affected by the beam irradiated to the exposure pixel P11. Therefore, if a region formed by the exposure pixels P00 to P22 is defined as “unit region E”, the data conversion unit 201 can set 1 in accordance with a pattern in one unit region E (partial pattern in the pattern data 210). It can be seen that the light quantity of the beam formed by the two exposure pixels P11 needs to be determined.

  5 and 6 that one unit region E includes 15 × 15 (= 225) control pixels Q. The control pixel Q that is the optical axis position of the beam irradiated to the exposure pixel P11 is the control pixel Q22.

  FIG. 7 is a flowchart showing a creation process executed by the data conversion unit 201. As shown in FIG. 7, in order to create the light quantity data 211, the data conversion unit 201 first creates edge light quantity data (step S11).

  In step S11, the data conversion unit 201 obtains the light amount value of the beam when the control pixel Q corresponds to a pixel (edge control pixel) constituting the edge of the pattern, based on the beam characteristic data described above. This light quantity value is obtained for 225 control pixels Q existing in the unit area E and stored as edge light quantity data. That is, the edge light quantity data is 225 multi-value data in which each value corresponds to the control pixel Q.

  In general, the light amount value obtained in step S11 is the distance and direction (ie, vector) between the position of the corresponding control pixel Q in the unit region E and the optical axis position of the beam (the position of the control pixel Q22 in the exposure pixel P11). Dependent. However, in this embodiment, as described above, since the cross-sectional shape of the beam is circular, it does not depend on the direction.

  Next, the data conversion unit 201 determines an exposure pixel P of interest (step S12), and determines a unit region E in which the determined exposure pixel P is the exposure pixel P11. Further, the pixel values of 225 control pixels Q included in the determined unit region E are acquired from the pattern data 210 (step S13). Since the pixel value in the pattern data 210 is binary, the data acquired in step S13 is 225 bit data.

  FIG. 8 is an example of the pattern data 210. The shaded control pixel Q in FIG. 8 indicates the control pixel Q whose pixel value in the pattern data 210 is “1”. The unit region E shown in FIG. 8 is an example of the unit region E determined in step S12, and the pixel value of the control pixel Q included in the unit region E is acquired in step S13.

  Next, the data conversion unit 201 performs an edge detection process on the pixel value acquired in step S13, and detects a control pixel Q constituting an edge in the pattern as an edge control pixel EQ (step S14). In addition, since various methods proposed conventionally can be applied to the edge detection processing, detailed description is omitted here.

  FIG. 9 is a diagram illustrating the edge control pixel EQ. FIG. 9 shows edge control pixels EQ detected in the unit region E shown in FIG. In the example shown here, 15 control pixels Q are detected as edge control pixels EQ.

  When step S14 is executed, the data conversion unit 201 acquires the light amount value for each edge control pixel EQ detected in step S14 from the edge light amount data obtained in step S11 (step S15).

  Next, the data conversion unit 201 determines the optimum value as the light amount value of the exposure pixel P determined in step S12 from the light amount value acquired in step S15 (the number of detected edge control pixels EQ exists). In step S16, the light quantity value 211 of the exposure pixel P is stored in the light quantity data 211. In the present embodiment, the optimum value is “minimum value”, but the rule for selecting the optimum value is not limited to this, and may be “average value”, for example. The same applies to the following embodiments.

  When step S16 is executed, the data conversion unit 201 determines whether or not step S16 has been executed for all exposure pixels P (step S17).

  If there is an exposure pixel P for which the light amount value has not yet been determined (No in step S17), the process returns to step S12 and the process is repeated. On the other hand, when the light quantity value has already been determined for all the exposure pixels P (Yes in step S17), the data conversion unit 201 ends the creation of the light quantity data 211.

  Note that the data conversion unit 201 controls the control pixel Q22 in the exposure pixel P determined in step S12 (the control pixel Q serving as the optical axis position of the beam, in terms of the unit region E, the control pixel Q22 in the exposure pixel P11). ) Is “0” in the pattern data 210, the processing of steps S14 and S15 is not executed, and the light amount of the exposure pixel P is determined to be “0” in step S16. That is, the case where the pixel value of the optical axis position of the beam is “0” means that it is not necessary to expose the position, and it is not necessary to irradiate the beam.

  FIG. 10 is a diagram illustrating an example of the unit region E in which the light amount value of the exposure pixel P11 is “0”.

  In this manner, the data conversion unit 201 is created based on the exposure pixel P having a relatively low resolution from the pattern data 210 that is binary bitmap data having a high resolution created based on the control pixel Q. Light amount data 211 that is multi-valued bitmap data is created.

  In the present embodiment, it has been described that the beam characteristic data is stored in advance, but edge light amount data may be stored instead of the beam characteristic data. In that case, it is not necessary to store the beam characteristic data, and even if new pattern data 210 is input and it is necessary to create new light quantity data 211, edge light quantity data is created each time. There is no need to do.

  Further, in the present embodiment, it has been described that the edge light amount data is created for all the control pixels Q. However, after the edge control pixel EQ is detected, only the detected edge control pixel EQ has the beam characteristics. The light amount value may be determined based on the data.

  FIG. 11 is a diagram illustrating an example of the pattern data 210. As already described, the pattern data 210 is bitmap data in which a pattern exposed by the control pixel Q having a size corresponding to the control pitch is expressed in binary (“1” or “0”). The thick line L indicates the edge of the pattern to be exposed.

  FIG. 12 is a diagram showing the light amount data 211 created from the pattern data 210 shown in FIG. As shown in FIG. 12, the light quantity data 211 is a multi-value pattern (in the example shown in FIG. 12, “100”, “85”, “75”, “ 60 ”,“ 45 ”or“ 0 ”). Note that FIG. 12 shows an exposure area exposed by a beam for exposing the edge of the pattern (that is, an exposure area constituting the edge of the pattern). These exposure areas are circular diameter areas having different diameters as shown in FIG.

  Next, a method for exposing a pattern to the substrate 9 based on the light amount data 211 will be described.

  FIG. 13 is a flowchart showing an exposure method according to the present invention. However, it is assumed that the creation process (FIG. 7) already described is executed by the data conversion unit 201 of the exposure apparatus 1 before each process shown in FIG. 13 is started. The exposure apparatus 1 will be described assuming that the laser oscillator 13 exposes the pattern expressed in the pattern data 210 by irradiating the laser beam M times.

  First, the CPU 20 initializes the value of the counter m for counting the number of exposures to “1” (step S21), and then moves the movable stage 10 to the m-th exposure position (step S22).

  Next, the light quantity control unit 200 executes a light quantity control process based on the light quantity data 211 (step S23).

  FIG. 14 is a flowchart showing the light amount control process. When the light amount control process is started, the light amount control unit 200 first initializes the value of the counter n indicating the number of the exposure pixel P to “1” (step S31).

Next, the light amount of the nth exposure pixel P is acquired from the light amount data 211 (step S32), and the elapsed time tn of the _nth micromirror is obtained based on the acquired light amount and Expression 5 (step S33). . For the micromirror corresponding to the exposure pixel P with the light amount “0”, the elapsed time t _n is “U” for convenience (where U> T).

When n-th elapsed time t _n of the micro-mirror is obtained, an elapsed time t _n determined to set as a delay time of the reset signal for the micro-mirror (step S34).

  Next, the value of the counter n is incremented (step S35), and it is determined whether or not the value of the counter n is greater than N (step S36). The spatial light modulation device 15 is provided with N micromirrors, and N exposure pixels P are exposed by one exposure. When step S36 is executed, the case where the value of the counter n is equal to or smaller than N is a case where the processing for the N exposure pixels P has not yet been completed, so the processing returns to step S32 and the processing is repeated.

  On the other hand, when step S36 is executed, the case where the value of the counter n is greater than N means that the process of setting the delay time for the N micromirrors included in the spatial light modulation device 15 (step S34) has been completed. Indicates. Therefore, in this case, the light amount control unit 200 determines Yes in step S36, and transmits the start signal to the micromirror that has passed the delay time set in step S34 (step S37), while the previous exposure (m−1th time). It is monitored whether or not time has passed since the exposure T) (step S38).

Then, when the time has elapsed by the period T (Yes in step S38), the light amount control process shown in FIG. 14 is terminated and the process returns to the process shown in FIG. Thereby, for the micromirror in which the value “U” larger than the period T is set as the delay time, the start signal is not transmitted because step S37 is not executed. Therefore, the micromirror remains in a state in which the beam is turned _off (state of the arrangement angle θ _off ), and the light amount of the beam by the micromirror becomes “0”.

  Returning to FIG. 13, when the light amount control processing in step S <b> 23 is completed, the control unit 2 transmits the m-th reset signal to the laser oscillator 13, and the laser light is emitted by the laser oscillator 13. The irradiated laser light is guided to the spatial light modulation device 15 by the illumination optical system 14, and is modulated into a plurality of beams (multi-beamed) by the spatial light modulation device 15. The beam formed by each micromirror has a light amount corresponding to the arrangement angle θ of each micromirror when the laser beam is incident, and is guided to the imaging optical system 16 and irradiated toward the substrate 9. At this time, a plurality of beams are irradiated from the exposure head 11 at a beam pitch, thereby performing pattern exposure (step S24).

  When step S24 is executed and the m-th exposure is completed, the value of the counter m is incremented (step S25), and it is determined whether or not the value of the counter m is greater than “M” (step S26). The case where the value of the counter m is equal to or less than M when step S26 is executed means that the exposure (step S24) has not been executed M times yet. In this case, the pattern exposure is not completed. It returns to step S22 and repeats a process. On the other hand, the case where the value of the counter m is larger than M when step S26 is executed means that the exposure (step S24) has already been executed M times. In this case, the exposure of the pattern is completed. Determine and end the process.

  FIG. 15 is a diagram showing a pattern to be exposed based on the light amount data 211 shown in FIG. However, circles are not shown for some of the exposure areas other than the exposure areas that form the edges of the pattern.

  When the pattern is exposed by executing step S24 based on the light amount data 211 shown in FIG. 12, the shaded area in FIG. 15 becomes an area exposed by each beam, and this area becomes an area for forming a pattern. . The exposure apparatus 1 in the present embodiment can expose a pattern at a control pitch smaller than the beam pitch, and expresses a smoother edge along the thick line L than the edge of the pattern by the conventional exposure method shown in FIG. is made of.

  As described above, the exposure apparatus 1 according to the first embodiment has the light amount data 211 representing the pattern by the laser oscillator 13 that irradiates the illumination light to be a beam and the exposure pixel P having a size corresponding to a predetermined beam pitch. Based on the above, a light amount control unit 200 that controls the light amount of the beam, and a pattern is exposed at a control pitch smaller than at least the predetermined beam pitch while irradiating the beam controlled by the light amount control unit 200 at a predetermined beam pitch Since the exposure head 11 is provided, a control pitch smaller than the beam pitch can be set as the exposure resolution, so that the pattern can be exposed with a resolution superior to the resolution depending on the size of the beam pitch.

  In addition, the exposure apparatus 1 further includes a data conversion unit 201 that creates light amount data 211 based on the pattern data 210 representing a pattern by the control pixels Q having a size corresponding to the control pitch. The pattern can be exposed simply by applying to.

<2. Second Embodiment>
In the first embodiment, the function of converting the pattern data 210 into the light amount data 211 has been described as being realized by the data conversion unit 201 as a functional block realized by software. However, such a function may be realized by hardware.

  FIG. 16 is a view showing an exposure apparatus 1a according to the second embodiment. The exposure apparatus 1a in the second embodiment is different from the exposure apparatus 1 in the first embodiment in that a control unit 2a is provided instead of the control unit 2. The control unit 2a includes a data conversion unit 3 that is mainly realized as hardware, and has a functional block corresponding to the data conversion unit 201 although not illustrated. This is different from the control unit 2 in the first embodiment. Hereinafter, the exposure apparatus 1a according to the second embodiment will be described while omitting the description of points common to the exposure apparatus 1 according to the first embodiment as appropriate.

  FIG. 17 is a diagram illustrating a configuration of the data conversion unit 3 according to the second embodiment. As shown in FIG. 17, the data conversion unit 3 includes a unit area memory 30, eight LUT circuits 31, 32, 33, 34, 35, 36, 37, 38, and a selection circuit 39.

  The unit area memory 30 can read out and buffer the pixel values of all the control pixels Q (15 × 15) included in the unit area E of interest from the pattern data 210 stored in the storage device 21. It is a memory with a possible storage capacity. However, the unit region memory 30 only needs to store at least the pixel values of the control pixels Q (57) indicated by hatching in FIG.

  Each of the LUT circuits 31 to 38 has a control pixel Q (any direction) arranged in the respective directions (eight directions) shown in FIG. 17 from the control pixel Q (black control pixel Q in FIG. 17) serving as the optical axis position of the beam. 7 is also an input signal (becomes a 7-bit signal). That is, seven control pixels Q arranged in the respective directions are input from the unit area memory 30 to each LUT circuit 31 to 38.

  When the control pixel Q22 of the exposure pixel P00 existing in the upper left direction with respect to the control pixel Q serving as the optical axis position of the beam is the edge control pixel EQ, the LUT circuit 31 receives an input signal indicating “0011111”. Is done. In the present embodiment, in the input signal input to each LUT circuit 31 to 38, the lower pixel indicates the control pixel Q located closer to the center in the unit region E. However, which bit of the input signal corresponds to which of the seven control pixels Q may be freely set.

  Each of the LUT circuits 31 to 38 constitutes a look-up table, and stores the light amount value when each of the seven control pixels Q becomes the edge control pixel EQ. The light amount value referred to here can be obtained and stored for each control pixel Q in accordance with the beam characteristic data.

  In the first embodiment, as edge light quantity data, light quantity values are obtained and stored for all control pixels Q (225 control pixels Q) constituting the unit region E. However, the exposure apparatus 1a in the second embodiment performs light quantity only in a predetermined direction (8 directions) from the position of the control pixel Q corresponding to the optical axis position of the beam (7 × 8 directions = 56). You only need to memorize the value. Therefore, the data converter 3 can create the light quantity data 211 at high speed with a simple configuration.

  Each of the LUT circuits 31 to 38 selects one of the light amount values stored in the lookup table (the light amount value when the control pixel Q indicated by the input signal becomes the edge control pixel EQ) according to the input signal. The data is output to the selection circuit 39.

  The selection circuit 39 selects the optimum value (minimum value) from the light amount values input from the LUT circuits 31 to 38, and sets the light amount value of the exposure pixel P (the exposure pixel P11 in the unit area E of interest). . As a result, the data conversion unit 3 creates light amount data 211 in the storage device 21.

  FIG. 18 is a diagram conceptually illustrating a state in which the data conversion unit 3 in the second embodiment performs determination in eight directions for the pattern data 210 and the unit area E illustrated in FIG. As illustrated in FIG. 18, the data conversion unit 3 determines only with patterns in eight directions. Therefore, the light quantity value input to the selection circuit 39 is also eight.

  In the example shown in FIG. 18, the light amount value (output value of the LUT circuit 33) of the edge control pixel EQ (control pixel Q13 of the exposure pixel P11) detected in the upper right direction is the minimum value. Therefore, this value is output from the selection circuit 39 and becomes the light amount value of the exposure pixel P11.

  As described above, the exposure apparatus 1a according to the second embodiment includes the data conversion unit 3 that determines only the eight directions from the position of the control pixel Q corresponding to the optical axis position of the beam, whereby all the controls are performed. Compared with the case where the edge is detected for the pixel Q, the light quantity data 211 can be created at a higher speed. The predetermined direction is not limited to eight directions, and may be four directions or 16 directions.

  Moreover, by simplifying in this way, the data conversion part 3 can be easily implement | achieved by hardware, and the light quantity data 211 can be produced at higher speed compared with the case where it implement | achieves by software. However, part or all of the functions of the data conversion unit 3 in the second embodiment may be realized by software. Even in such a case, the light amount data 211 can be generated at a higher speed than the data conversion unit 201 in the first embodiment by limiting the edge detection to eight directions.

  In the data converter 3 in the second embodiment, the pixel value of the control pixel Q (control pixel Q22 of the exposure pixel P11) at the optical axis position of the beam is the pattern data 210 as in the first embodiment. In the case of “0”, the light amount value of the exposure pixel P11 is set to “0”.

<3. Third Embodiment>
The method of converting the pattern data 210 into the light amount data 211 is not limited to the method of detecting the edge control pixel EQ.

  FIG. 19 is a view showing the data conversion unit 4 of the exposure apparatus 1b in the third embodiment. The exposure apparatus 1b in the third embodiment is different from the exposure apparatus 1a in the second embodiment in that it includes a data conversion unit 4 instead of the data conversion unit 3. Hereinafter, differences of the exposure apparatus 1b according to the third embodiment from the exposure apparatus 1a will be described.

  The data conversion unit 4 includes a unit area memory 40, a memory 48, a selection circuit 49, s template memories 411 to 41s, and s matching circuits 421 to 42s (s is an integer of 2 or more, provided that , S is preferably about 10.)

  The unit area memory 40 has a configuration equivalent to the unit area memory 30 and has a storage capacity capable of buffering the pixel values of all control pixels Q (225 control pixels Q) included in the unit area E of interest. It is memory. FIG. 19 shows a state in which pixel values are read into the unit area memory 40 for the pattern data 210 and the unit area E shown in FIG.

  Corresponding matching circuits 421 to 42s are provided in the template memories 411 to 41s. In each of the template memories 411 to 41s, bitmap data of an exposure area corresponding to the light amount of the beam is stored as a template one by one. That is, the template memories 411 to 41 s store different templates, and the data conversion unit 4 stores s templates. Each template can be obtained in advance by experiment for each light amount of the beam.

  The templates stored in the template memories 411 to 41s are input as patterns to the matching circuits 421 to 42s corresponding to the stored template memories 411 to 41s.

  Each of the matching circuits 421 to 42s receives a pattern stored in the unit area memory 40 and a template pattern stored in the corresponding template memory 411 to 41s, and performs matching processing on the two patterns. Is called. Various methods have been proposed for matching the two patterns, and the details can be omitted because they can be used as appropriate.

  Each of the matching circuits 421 to 42s outputs the result of the matching process to the selection circuit 49.

  The memory 48 stores template light quantity data 480 indicating the light quantity value corresponding to each template. The light amount value stored as the template light amount data 480 is acquired and stored as the light amount of the beam when each template is obtained by experiment.

  The selection circuit 49 determines the best matching template according to the input from each of the matching circuits 421 to 42s, and acquires the light amount value corresponding to the template by referring to the template light amount data 480.

  For example, if the matching result from the matching circuit 421 is the best, the selection circuit 48 best matches the template stored in the template memory 411 with the pattern stored in the unit area memory 40. Determine as. Further, the light amount value corresponding to the template stored in the template memory 411 is acquired from the template light amount data 480 of the memory 48 and used as the light amount value of the exposure pixel P11 of the unit area E of interest.

  As described above, the light amount data 211 can be generated by the data conversion unit 4 also in the exposure apparatus 1b according to the third embodiment. Further, the exposure apparatus 1b can process the light amount data 211 at a high speed by creating the light amount data 211 by the data conversion unit 4 mainly composed of hardware. However, some or all of the functions of the data converter 4 may be realized by software.

<4. Fourth Embodiment>
The method for obtaining the light amount data 211 from the pattern data 210 is not limited to the example shown in the above embodiment.

  FIG. 20 is a view showing the data conversion unit 3a of the exposure apparatus 1c in the fourth embodiment. The exposure apparatus 1c in the fourth embodiment is different from the exposure apparatus 1a in the second embodiment in that a data conversion unit 3a is provided instead of the data conversion unit 3. In the following, in the exposure apparatus 1c according to the fourth embodiment, differences from the exposure apparatus 1a will be mainly described.

  The data conversion unit 3 a includes a unit area memory 30 a, nine LUT circuits 310 to 318, and a selection circuit 39.

  The unit area memory 30a is a memory having a storage capacity capable of buffering the pixel values of all the control pixels Q (225 control pixels Q) included in the unit area E of interest. 20 shows a state in which pixel values are read into the unit area memory 30a for the pattern data 210 and the unit area E shown in FIG.

  In the LUT circuits 310 to 318, the pixel values of the corresponding exposure pixels P00 to P22 in the unit area E of interest are input as input signals. In other words, the pattern in the unit region E is divided into nine according to the exposure pixels P00 to P22 constituting the unit region E, and each divided pattern is input to the corresponding LUT circuits 310 to 318 one by one.

  For example, among the 225 pixel values stored in the unit area memory 30a, the LUT circuit 310 receives the pixel values of the 25 control pixels Q constituting the exposure pixel P00. The LUT circuit 318 receives the pixel values of the 25 control pixels Q constituting the exposure pixel P22 among the 225 pixel values stored in the unit area memory 30a. Therefore, the input signals to the LUT circuits 310 to 318 are all 25-bit signals.

  The LUT circuits 310 to 318 form a look-up table that uses an input signal (a signal expressing a pattern divided for each exposure pixel P) as an address. The data stored at each address is a light quantity value of the beam that most accurately reproduces the pattern expressed in the input signal when the exposure pixel P11 is irradiated.

  Therefore, for example, when the pixel values of the 25 control pixels Q constituting the exposure pixel P00 of the unit area E of interest are input to the LUT circuit 310, the unit region E of interest of interest is reproduced in order to reproduce the pattern of the exposure pixel P00. The LUT circuit 310 outputs the most suitable light amount value of the beam to be irradiated to the exposure pixel P11.

  That is, when an input signal is given to each of the LUT circuits 310 to 318, the light quantity value most suitable for exposing the pattern (divided pattern) shown in the exposure pixels P00 to P22 constituting the unit area E of interest is obtained. Output from each LUT circuit 310 to 318 toward the selection circuit 39.

  The selection circuit 39 selects the minimum value as the optimum value from the nine input light quantity values, and determines the selected light quantity value as the light quantity value of the beam irradiated to the exposure pixel P11 in the unit area E of interest.

  As described above, the data conversion unit 3a of the exposure apparatus 1c according to the fourth embodiment can create the light amount data 211 while referring to the lookup table. In the exposure apparatus 1c, it has been described that the data conversion unit 3a is mainly realized by hardware. However, part or all of the functions of the data conversion unit 3a may be realized by software.

<5. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made.

For example, in the above embodiment, it has been described that the light amount data 211 is data in which the light amount value for each exposure pixel is stored. However, the data conversion units 201, 3, 3 a, and 4 have elapsed time according to Equation 5 for each exposure pixel. optionally the light quantity data 211 so calculated in advance to the t _n (the delay time data is a substantial sense). In this case, the light quantity control unit 200 does not need to calculate Equation 5. That is, the light amount data 211 may be data that does not directly indicate the light amount value as long as it is a value determined according to the light amount and can control the light amount of the beam.

  Further, it has been described that the light amount data 211 is created by the exposure apparatus 1 based on the pattern data 210. However, data corresponding to the light amount data 211 may be generated by an external computer and then input to the exposure apparatus 1 and stored. That is, the data corresponding to the light amount data 211 is not limited to the configuration created by the exposure apparatus 1.

  Moreover, each process shown in the said embodiment is an example, Comprising: It is not limited to this. That is, as long as the same effect can be obtained, the contents and order of each step may be changed as appropriate.

It is a figure which shows the exposure apparatus in 1st Embodiment. It is a figure which shows the functional block which exposure apparatus has with the flow of data. It is a figure which illustrates the entrance plane formed in the surface of an aperture. It is a figure which shows the light quantity distribution when the light quantity of a beam is changed, and the exposure area | region in the beam of each light quantity. It is a figure which shows an exposure pixel. It is a figure which shows a unit area | region. It is a flowchart which shows the creation process performed by the data converter. It is an example of pattern data. It is a figure which shows an edge control pixel. It is a figure which shows the example of the unit area | region where the light quantity value of an exposure pixel is set to "0". It is a figure which shows the example of pattern data. It is a figure which shows the light quantity data produced from the pattern data shown in FIG. 3 is a flowchart showing an exposure method according to the present invention. It is a flowchart which shows a light quantity control process. It is the figure which showed the pattern exposed based on the light quantity data shown in FIG. It is a figure which shows the exposure apparatus in 2nd Embodiment. It is a figure which shows the structure of the data converter in 2nd Embodiment. It is a figure which shows notionally a mode that the data converter in 2nd Embodiment performs determination about 8 directions about the pattern data and unit area | region shown in FIG. It is a figure which shows the data converter of the exposure apparatus in 3rd Embodiment. It is a figure which shows the data converter of the exposure apparatus in 4th Embodiment. It is a figure which shows notionally the image data at the time of exposing a pattern. It is a figure which shows the state which exposed the pattern according to the image data shown in FIG.

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c Exposure apparatus 10 Movable stage 11 Exposure head 13 Laser oscillator 14 Illumination optical system 15 Spatial light modulation device 16 Imaging optical system 2, 2a Control part 200 Light quantity control part 201, 3, 3a, 4 Data conversion Section 21 Storage device 210 Pattern data 211 Light quantity data 9 Substrate

Claims (8)

An exposure apparatus that exposes a pattern on an object with a beam irradiated at a predetermined beam pitch,
A light source that emits illumination light to be the beam;
A light amount control means for controlling the light amount of the beam based on multi-value data expressing the pattern by exposure pixels having a size corresponding to the predetermined beam pitch;
An exposure head that exposes the pattern at a control pitch smaller than at least the predetermined beam pitch while irradiating the beam controlled by the light amount control means at the predetermined beam pitch;
Data conversion means for creating the multi-value data by detecting edge control pixels which are control pixels constituting the edges of the pattern in pattern data expressing the pattern by control pixels having a size corresponding to the control pitch; ,
Bei to give a,
The data conversion means is an exposure apparatus that detects the edge control pixel only in a predetermined direction from the position of the control pixel corresponding to the optical axis position of the beam . The exposure apparatus according to claim 1,
The data conversion means is an exposure apparatus that creates the multi-value data by matching the pattern in the pattern data with a pattern exposed by the beam in accordance with a light amount of the beam . The exposure apparatus according to claim 1 ,
The data conversion means is an exposure apparatus that creates the multi-value data while referring to a lookup table . An exposure apparatus according to any one of claims 1 to 3 ,
A spatial light modulation unit that modulates illumination light from the light source into a plurality of beams by a plurality of micromirrors;
The light amount control means is an exposure apparatus that individually controls the light amounts of the plurality of beams . An exposure method for exposing a pattern to an object with a beam irradiated at a predetermined beam pitch,
(a) irradiating illumination light as the beam from a light source;
(b) controlling the light amount of the beam based on multi-value data representing the pattern by exposure pixels of a size corresponding to the predetermined beam pitch;
(c) exposing the pattern at a control pitch smaller than at least the predetermined beam pitch while irradiating the beam controlled in the step (b) from the exposure head at the predetermined beam pitch;
(d) creating the multi-value data by detecting edge control pixels which are control pixels constituting the edges of the pattern in pattern data representing the pattern by control pixels having a size corresponding to the control pitch. When,
I have a,
The step (d) is an exposure method in which the edge control pixel is detected only in a predetermined direction from the position of the control pixel corresponding to the optical axis position of the beam . The exposure method according to claim 5,
The step (d) is an exposure method in which the multi-value data is created by matching the pattern in the pattern data with a pattern exposed by the beam according to the light amount of the beam . The exposure method according to claim 5,
In the exposure method, the step (d) is a step of creating the multi-value data while referring to a lookup table . An exposure method according to any one of claims 5 to 7 ,
(e) further comprising the step of modulating the illumination light from the light source into a plurality of beams by a plurality of micromirrors provided in the spatial light modulation means;
In the exposure method , the step (b) is a step of individually controlling the light amounts of the plurality of beams .

Images