KR20060045401A - Laser drawing apparatus and method, and method of forming photomask - Google Patents

Abstract

Even when the exposure target formed with the resist film (photosensitive resin film) on the surface portion is large, such as a large sized photomask, the productivity does not decrease, and the optimum exposure amount is prevented even when the film thickness variation of the resist film in the minute region is changed. Provided is a laser drawing apparatus that can set a drawing pattern including a fine pattern and can perform a good drawing pattern without being affected by the change in the film thickness of the resist film.

The drawing head 1 for irradiating the exposure light beam to the exposure object 101, the scanning means 5 for moving the irradiation position of the exposure light beam R on the exposure object 101, and the exposure object 101 from the exposure object 101. On the basis of the measurement result by the film thickness measuring means 24 which measures the film thickness of the resist film 102 based on the light beam opposite to the exposure light beam R, and the preset drawing pattern and the film thickness measuring means 24. Modulation means 4 for modulating the intensity of the light beam for exposure is provided.

Resist film, photosensitive resin, exposure, photomask, pattern, drawing, luminous flux, scanning, film thickness, modulation, laser, deflection, light source, emission, lens

Description

LASER DRAWING APPARATUS AND METHOD, AND METHOD OF FORMING PHOTOMASK}

1 is a block diagram showing a configuration of a first embodiment of a laser drawing apparatus according to the present invention.

Fig. 2 is a perspective view showing the configuration of a drawing head according to a first embodiment of the laser drawing device.

3 is a plan view for explaining a raster scanning method which is a drawing method according to the laser drawing apparatus.

4 is a flowchart showing an operation according to the first embodiment of the laser drawing apparatus.

Fig. 5 is a side view showing the structure of a writing head according to a second embodiment of a laser drawing apparatus according to the present invention.

FIG. 6 is a block diagram showing a configuration of a second embodiment of the laser drawing apparatus. FIG.

Fig. 7 is a flowchart showing the operation of the second embodiment of the laser drawing apparatus.

* Description of the symbols for the main parts of the drawings *

1: Writing head 2: Output lens

3: light source 4: modulator

5: deflection element 6: moving stage

24: film thickness measuring circuit 25: optical head

101 substrate 102 resist film

According to the present invention, a predetermined drawing pattern is drawn by irradiating a light beam for exposure to an exposed object in which a resist film (photosensitive resin film) is formed on a surface such as a semiconductor wafer, a liquid crystal display device (LCD) or a photomask substrate, or an optical disk substrate. A laser drawing apparatus, a laser drawing method, and a manufacturing method of a photomask are provided.

Conventionally, a laser drawing apparatus for drawing a predetermined drawing pattern on an exposed object formed with a resist film (photosensitive resin film) on the surface, such as a semiconductor wafer, a liquid crystal display device (LCD) or a photomask substrate, or an optical disk substrate, It is proposed.

In addition, Japanese Laid-Open Patent Publication No. 2003-500847 (hereinafter referred to as "Patent Document 1") causes distortion in the drawing pattern when drawing a predetermined drawing pattern by using a laser drawing device on a substrate such as a large photomask. The laser drawing apparatus which collects the information for anticipating this in advance, predicts distortion based on this information, produces | generates the correction map for reducing this distortion, and performs pattern drawing based on this correction map. Is disclosed.

In this laser drawing apparatus, as information for anticipating distortion occurring in the drawing pattern, variation in the thickness of the resist film is collected. The measurement regarding the variation of the resist film thickness is performed using a contact type film thickness meter. Information on the variation in the thickness of the resist film is collected by applying a resist to a dummy substrate and measuring the thickness of the resist film by a contact film thickness meter at a plurality of locations on the dummy substrate.

Here, when the film thickness variation of the resist film exceeds a specific region, the coating conditions are changed by adjusting a resist coater (resist coating apparatus), and the resist is applied to the dummy substrate again, so that the film thickness variation is within a specific range. Got to listen.

In addition, in the correction map, in order to correct the line width in the drawing pattern according to the information of the thickness variation of the resist film located at each place of the drawing pattern, the amount of correction of the exposure amount (dose amount) at each place of the drawing pattern is adjusted. The decision is made.

The substrate to which the exposure is actually performed is coated with a resist under the same conditions as the dummy substrate, and the exposure corresponding to the predetermined drawing pattern is performed while correcting the exposure amount (dose amount) based on the correction map.

By the way, in the laser drawing apparatus as mentioned above, since the resist should be apply | coated to a dummy board | substrate and the film thickness of a resist film should be measured separately from the board | substrate which actually exposes, there existed a problem which lowered productivity by that much. Particularly, in a large size photomask in which at least one side of the quadrangular substrate is 300 mm or more, measuring the film thickness of the resist film on the entire surface of the photomask has a problem of greatly lowering the productivity.

However, if the film thickness of the resist film is measured for only a few places in the dummy substrate, the accuracy of the exposure dose correction is lowered. In this case, the optimum exposure is not set for the variation in the thickness of the resist film in the minute region, and for the drawing pattern including the fine pattern, the film thickness of the resist film is affected and quality deterioration occurs.

In view of the above, the present invention has been proposed in view of the above-described problems, and even when the exposed object formed on the surface portion of the resist film (photosensitive resin film) is large, such as a large photomask, the productivity is not reduced. The optimum exposure dose is also set for the variation in the thickness of the resist film in the minute region, and the laser capable of performing a good drawing pattern without affecting the variation in the thickness of the resist film even for the drawing pattern including the fine pattern. An object thereof is to provide a writing apparatus, a laser drawing method and a photomask manufacturing method.

The laser drawing apparatus which concerns on this invention for solving the above-mentioned subject is provided with the following structures.

[Configuration 1]

The laser drawing apparatus according to the present invention includes a drawing head for irradiating an exposure light beam to an exposure object having a resist film formed on its surface, scanning means for moving the irradiation position of the exposure light beam on the exposure object, and the intensity of the light beam for exposure. Modulating means for modulating, and film thickness measuring means for measuring the film thickness of said resist film based on the light flux opposite to the light flux for exposure from the exposure object, wherein the modulating means is measured by a preset drawing pattern and film thickness measuring means. The intensity of the light beam for exposure is modulated based on the result.

[Configuration 2]

The laser drawing apparatus according to the present invention includes a drawing head for irradiating a light beam for exposure to an exposed object having a resist film formed on its surface, an optical head for irradiating a light flux for measuring film thickness to an exposed object, a light beam for exposure on an exposed object, and the film thickness Scanning means for shifting the irradiation position of the measuring light beam, modulating means for modulating the intensity of the light beam for exposure, and film thickness measuring means for measuring the film thickness of the resist film based on the luminous flux opposite to the film thickness measuring light beam from the exposure object And the film thickness measuring light flux is irradiated prior to this light flux at a position where the light beam for exposure is irradiated from the exposure object, and the modulating means is based on a preset drawing pattern and the measurement result by the film thickness measuring means. To modulate the intensity of the light beam for exposure.

[Configuration 3]

In the laser drawing apparatus of the structure 2, this invention WHEREIN: The space | interval between the irradiation position of the light beam for exposure on an exposure object, and the irradiation position of the light beam for measuring film thickness on an exposure object consists of 10 mm or less, It is characterized by the above-mentioned. will be.

[Configuration 4]

The laser drawing method according to the present invention irradiates an exposure light beam by a drawing head to an exposure object having a resist film formed on a surface thereof, moves the irradiation position of the exposure light beam on the exposure object, and reverses the exposure light beam from the exposure object. The film thickness of the resist film is measured based on the luminous flux, and the intensity of the luminous flux for exposure is modulated on the basis of a preset drawing pattern and the measurement result of the film thickness of the resist film.

[Configuration 5]

In the laser drawing method according to the present invention, an exposure light beam is irradiated to an exposed object having a resist film formed on its surface by a drawing head, and a light flux for measuring film thickness is irradiated to the exposed object, and the film thickness is measured on the exposed object. The irradiation light beam of the exposure light beam and the film thickness measurement light beam on the exposure object is moved so that the light beam is irradiated to the position to which the exposure light beam is irradiated prior to the exposure light beam, and the film from the exposure object. The film thickness of the resist film is measured based on the light beam opposite to the light beam for thickness measurement, and the intensity of the light beam for exposure is modulated based on a preset drawing pattern and a measurement result of the film thickness of the resist film.

[Configuration 6]

In the method for manufacturing a photomask according to the present invention, a photomask blank having a resist film on its surface is irradiated with an exposure light beam by a drawing head, and the irradiation position of the exposure light beam on the photomask blank is moved, and from the photomask blank. The film thickness of a resist film is measured based on the light beam opposite to the light beam for exposure, and the intensity | strength of the light beam for exposure is modulated based on the measurement result of the preset drawing pattern and the film thickness of a resist film.

[Configuration 7]

According to the method of manufacturing a photomask according to the present invention, a photomask blank having a resist film on its surface is irradiated with an exposure light beam by a drawing head, and a photomask blank is irradiated with a film thickness measurement light beam on a photomask blank. The film thickness measurement from the photomask blank is moved by moving the irradiation positions of the exposure light flux and the film thickness measurement light flux on the photomask blank so that the film thickness measurement light beam is irradiated to the position where the exposure light flux is irradiated prior to this exposure light flux. The film thickness of the resist film is measured based on the light beam opposite to the flux of light, and the intensity of the light beam for exposure is modulated based on a preset drawing pattern and the measurement result of the film thickness of the resist film.

In the laser drawing apparatus according to the present invention having such a configuration, the modulating means for modulating the intensity of the light beam for exposure irradiated by the drawing head with respect to the exposed object having the resist film formed on the surface thereof includes a preset drawing pattern and the exposed object. The intensity of the exposure light flux is modulated on the basis of the measurement result by the film thickness measuring means for measuring the film thickness of the resist film based on the light flux opposite to the light flux for exposure, and the resist is applied in real time based on the light flux for exposure without using a dummy substrate. The film thickness of the film is measured and drawing is performed by the light beam for exposure.

Therefore, in this laser drawing apparatus, it is not necessary to perform the film thickness measurement work before drawing, and the time required for the drawing work can be shortened. In this laser drawing apparatus, it is not necessary to mount a separate laser light source while measuring the film thickness of the resist film using the light beam for exposure, and the structure can be simplified.

Moreover, in the laser drawing apparatus which concerns on this invention, the modulation means which changes the intensity | strength of the exposure light beam irradiated by the drawing head with respect to the exposure object in which the resist film was formed in the surface part is a preset drawing pattern and the film thickness from an exposure object. The intensity of the exposure light beam is modulated on the basis of the measurement result by the film thickness measurement means for measuring the film thickness of the resist film based on the light beam opposite to the measurement light beam, and the resist is applied in real time based on the light beam for exposure without using a dummy substrate. The film thickness of the film is specified, and drawing is performed by the light beam for exposure.

Therefore, in this laser drawing apparatus, it is not necessary to perform the film thickness measurement work before drawing, and the time required for the drawing work can be shortened.

Moreover, in this laser drawing apparatus, the space | interval is made into 10 mm or less between the irradiation position of the exposure light beam in an exposure object, and the irradiation position of the film thickness measurement light beam on an exposure object, and it is the place where drawing by the exposure light beam is performed. Accurate film thickness measurement of the resist film is performed.

That is, the present invention does not reduce the productivity even when the exposure object formed on the surface portion of the resist film (photosensitive resin film) has a large size such as a large photomask, and also the variation in the film thickness of the resist film in the minute region. An optimum exposure amount is set, and the drawing apparatus which contains a fine pattern also provides the laser drawing apparatus which performs drawing of a drawing pattern favorably by being influenced by the film thickness change of a resist film.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment of Laser Drawing Apparatus]

The laser drawing apparatus which concerns on this invention is an apparatus which draws a desired pattern on a resist at the time of manufacturing a photomask etc.

As shown in FIG. 1, the laser drawing apparatus includes a writing head 1, a light source 3 for injecting a light beam into an exit lens 2 of the drawing head 1, and a light source 3 from the light source 3. A modulation element 4 serving as a modulation means for modulating the intensity of the emitted light flux R, a deflection element 5 serving as a scanning means for deflecting the optical path of the exposure light flux R, and an exit lens 2 And a moving stage 6 serving as scanning means for movably supporting the substrate 101 serving as the exposure target to which the light beam emitted from the light is irradiated.

The substrate 101 is a photomask blank used for manufacturing a photomask and the like, and a resist film (photosensitive resin) is applied to the surface portion to form a resist film 102, and the resist film 102 is subjected to a laser beam or the like. A desired pattern is drawn by this.

The drawing head 1 of this laser drawing apparatus, as shown in FIG. 2, has an output lens 2 which emits the light beam R for exposure downward and a base portion 7 supporting the output lens. Equipped. This drawing head 1 is supported by the laser drawing apparatus so that raising and lowering is possible through the slider 8. During the operation of the laser drawing apparatus, the drawing head 1 is lowered toward the surface of the substrate 101 to be the exposure object, approaches this surface portion, and with respect to the substrate 101 by scanning means. It operates while moving in the relatively horizontal direction. That is, the drawing head 1 irradiates the light beam for exposure upward of the surface of this board | substrate 101, moving the board | substrate 101 opposingly and horizontally through the space gap which is extremely narrow with respect to the surface.

Moreover, the relative movement of the drawing head 1 and the substrate 101 in the horizontal direction is performed by moving the substrate 10 in the horizontal direction by the moving stage 6, which supports the slider 8. It may be performed by moving the drawing head 1 by the moving stage 9.

Again, this drawing head is a means for maintaining a constant gap between the surface of the substrate 101 and, when lowered toward the substrate 101, a mechanism for radiating air flow toward the substrate 101. Equipped. In this drawing head 1, the pressure of the air flow radiated toward the board | substrate 101 and its own weight float in a balanced manner, and the clearance gap of the board | substrate 101 keeps a space | gap constant. That is, the drawing head 1 is lowered toward the substrate 101 by its own weight during the operation of the laser drawing apparatus, and floated by the pressure of the air flow radiating toward the substrate 101 from the lower surface portion. , It works. In this drawing head 1, the floating interval from the substrate 101 is extremely short, from about 10 µm to about 100 µm, in order to improve resolution and inspection ability due to the pressure of the air flow radiating toward the substrate 101. At intervals.

As the light source 3, for example, a He-Ca laser or the like that generates a light beam having a wavelength of 442 nm can be used. The exposure light beam R generated from this light source 3 is incident on the modulator 4 as shown in FIG. 1, and the intensity is modulated by the modulator 4. As the modulation element 4 is driven by the modulation drive 10, it modulates the intensity of the light beam R for exposure to pass.

The modulation drive 10 is supplied with data that has passed through the data input device 11, the data processing device 12, the memory 13, and the data reading device 14. Data is input to the data input device 11 in correspondence with a predetermined pattern for writing the resist film 102 on the substrate 101. Data input to the data input device 11 is transmitted to the data processing device 12 and processed as position data (XY coordinate data) and intensity data according to the pattern to be drawn. The data processed by the data processing device 12 is stored in the memory 13, read from the memory 13 by the data reading device 14, and transferred to the modulation drive 10.

In addition, the data output device 14 and the modulation drive 10 are controlled by the controller 15 and operate based on the clock output from the clock generator 16.

The light beam R for exposure intensity modulated by the modulation element 4 is incident on the deflection element 5 and deflects the emission direction by passing through the deflection element 5. The deflection element 5 is, for example, an acoustic-optical conversion element and, as driven by the scanning circuit 17, deflects the optical path of the light beam R for exposure to be transmitted at a constant cycle.

The scanning circuit 17 is controlled by the XY controller 18 controlled by the controller 17 and operates based on the clock output from the clock generator 16.

The exposure light beam R which deflects the emission direction by the deflection element 5 is incident on the exit lens 2, is focused on the resist film 102 on the substrate 101, and is irradiated. Thus, the light beam R for exposure irradiated on the board | substrate 101 is deflected by a fixed period and intensity-modulated according to the pattern drawn on the board | substrate 101. FIG.

Then, the XY controller 18 drives the moving stage 6 via the servo mechanisms 19, 20, 21, and 22, and as shown by arrows X and Y in FIG. This operation moves the substrate 101 and the drawing head 1 relatively in the horizontal direction at predetermined cycles.

The drawing method used in the present embodiment is generally called a raster scan method. In the raster scanning method, as shown in FIG. 3, the exposure light beam R scans the entire drawing area on the substrate 101, and when the pattern portion reaches the pattern portion, the intensity of the exposure light beam R increases to a predetermined value ( ON), and in the non-pattern part, it is lowered to a predetermined value (OFF).

In order to scan the entire drawing area, the scanning of the light beam R for exposure is scanned in the Y direction in a predetermined section (the Y-direction scanning unit of the light beam R for exposure), and when scanning of one section in the Y direction is completed, The exposure light beam R is moved in the X direction by the distance (the X-direction transmission unit of the exposure light beam R) to the area where the exposure light beam R is scanned next to the area adjacent to the area where the exposure light beam R is scanned. Delivered and it is repeated. When the drawing of the example is completed, the light beam R for exposure is transmitted to the next example, the same scan is repeated, and the whole drawing area is scanned.

In the following example, when the light beam R for exposure is transmitted, the Y-direction scanning units are provided with small overlapping portions to be adjacent to each other (single-pass drawing method) or in the Y-direction so as to have a predetermined weight in order to perform a large amount of exposure. There is a method of arranging scanning units (multipass drawing method).

In addition, the scanning of the light flux R for exposure in the Y direction is performed by the deflection of the light flux R for exposure, and the movement of the light flux R for exposure in the X direction is generally performed by moving a stage.

In this manner, the scanning on the substrate 101 of the light beam R for exposure intensity modulated by the modulation element 4 and the movement of the substrate 101 by the moving stage 6 are repeatedly performed, thereby onto the substrate 101. The predetermined pattern input to the data input device 11 is drawn. In addition, the drawing speed | rate performed in this way is about 300 mm <2> -1500 mm <2> per minute.

And this laser drawing apparatus is equipped with the film thickness measuring means which measures the film thickness of a resist film based on the reflection light beam of the excess light beam R from the board | substrate 10 which is an exposure object. That is, the luminous flux opposite to the luminous flux R from the substrate 101 reaches the luminous flux branching element 23 via the exit lens 2 and the deflection element 5. This luminous flux splitting element 23 is, for example, a beam split. The exposure light beam R mainly from the modulation element 4 to the deflection element 5 penetrates the light beam branch element 23. Then, the exposure light beam R for the return path from the deflection element 5 to the modulation element is branched from the optical path leading to the modulation element 4 by the light beam branch element 23, and the film thickness measurement is used as a film thickness measurement means. Incident on the circuit 24. The film thickness measuring circuit 24 detects the amount of opposite light incident thereon and calculates the film thickness of the resist film 102 based on the detection result.

The amount of light opposite to the light flux R for exposure from the substrate 101 is an interference between the reflected light from the surface of the resist film 102 and the light from the surface of the resist film 102, that is, the light from the surface of the substrate 101. Fluctuates by That is, since the reflected light amount of the exposure light flux R from the substrate 101 becomes a function of the film thickness of the resist film 102, if the relationship between the reflected light amount value and the film thickness is specified in advance, the result of detection of the opposite light amount The film thickness of the resist film 102 can be known.

In addition, in order to measure the film thickness of a resist using the exposure light beam R, the reflected light of the exposure light beam R needs to be generated from the substrate 101 at least. On the other hand, when operating a laser drawing apparatus, it is usually preferable that the reflected light of the light beam R for exposure is kept low for the reason of the drawing accuracy. Therefore, in the present embodiment, the reflectance from the substrate 101 may be adjusted in advance by a method such as controlling the film thickness of the resist in order to obtain the reflected light detectable within a range that does not adversely affect the drawing accuracy. .

Then, the film thickness of the resist film 102 detected by the film thickness measuring circuit 24 is sent to the modulation drive 10. The modulation drive 10 corrects the modulation amount of the modulation element 4 based on the film thickness value of the resist film 102. That is, the modulator 4 modulates the intensity of the light beam R for exposure based on the drawing pattern set in advance and the measurement result by the film thickness measurement circuit 24.

By the way, in the area | region where the predetermined | prescribed drawing pattern was drawn in the board | substrate 101, since the intensity | strength of the exposure light beam R is modulated corresponding to a drawing pattern, it changes in proportion to a reflected light flux and this intensity modulation. In this case, therefore, the film thickness of the resist film is determined based on the relationship between the intensity of the reflected light and the film thickness corresponding to the modulation intensity of the light beam R for exposure calculated and emitted in advance.

That is, in this laser drawing apparatus, as shown in the flowchart of FIG. 4, in step st1, the amount of reflected light of this light beam R for exposure is detected in the predetermined film thickness measurement section in the board | substrate 101. FIG. This film thickness measurement section is, for example, about 100 µm.

In step st2, the film thickness of the resist film 102 at the drawing point of the film thickness measurement section is calculated based on the light amount of the detected reflected light flux, the average value is calculated, and the calculated result is stored.

Step st3dpt determines whether the film thickness of the resist film 102 calculated in step st2 is included in the predetermined range, and if there is a value not included in the predetermined range, the process proceeds to step st4. If not in the range, go to step st6. Here, the predetermined range of the film thickness of the resist film 102 is, for example, in the range of ± 2.5% to 5% of the specified film thickness.

In step st6, the resist film 102 of the substrate 101 is judged to be defective, and a warning is displayed to indicate that it is defective. This alert may be made, for example, to generate a beep or to indicate some indication.

Step st4 determines the correction of the amount of light of the light flux R for exposure based on the film thickness of the resist film 102 calculated in step st2.

In step st5, the exposure dose dose is corrected according to the correction value determined in step st4, while drawing of the adjacent film thickness measurement section is performed and step st1 is performed.

As described above, in this laser drawing apparatus, the film thickness measurement of the resist film 102 in the film thickness measurement section in which no drawing is performed and the drawing in which the exposure amount is corrected based on the result of the film thickness measurement are repeated. As described above, the drawing of the predetermined drawing pattern is performed.

In the raster scanning method, when the scanning of the Y-direction scanning unit and the movement of the X-direction transmission unit of the exposure light beam R are repeatedly performed as described above, the Y-direction scanning unit includes an integer number of film thickness measurement sections. Setting is preferable practically. In the single pass method, it is preferable to set so as to include an integer number of film thickness measurement sections in the section excluding the overlap portion in the Y-direction scanning unit.

In this case, in the first Y-direction scanning unit according to each example, exposure compensation is not performed only by measuring the film thickness, and exposure compensation is performed from the next section. In addition, when setting so that two or more film thickness measurement sections may be included in the area | region except the Y-direction scanning unit or the overlap part, in the first section of each Y-direction scanning unit, the film thickness of the previous Y-direction scanning unit Exposure compensation is performed using the measurement results.

In addition, it is preferable practically to make the length of the X direction of a film thickness measurement area the same as the X direction transmission unit corresponded to the beam diameter of the light beam R for exposure. In addition, when setting so that one film thickness measurement section may be included in the area | region except the Y direction scanning unit or the overlap part, two or more X direction transmission units may be used as a film thickness measurement period.

The above method is to perform exposure compensation by reflecting the result of the measurement of the film thickness in the adjacent section. Since the film thickness does not fluctuate normally to a microscopic degree and fluctuates with the macroscopic tendency in the plane, sufficient effect is obtained. There is a number.

Second Embodiment of Laser Drawing Apparatus

In the laser drawing apparatus according to the present invention, as shown in FIG. 5, the optical head irradiates the light flux M for measuring the film thickness to the substrate 101 to be exposed, separately from the drawing head 1. (25) may be provided and configured.

In this case, this laser drawing apparatus is provided with the drawing head 1 and the optical head 25 which irradiates the light beam M for film thickness measurement, as shown in FIG. 6, and the deflection element 5 which becomes scanning means. ) And the moving stage 6 move the irradiation unit of the exposure light beam R, the film thickness measurement light beam R, and the film thickness measurement light beam M on the substrate 101. In other words, the exposure light beam R generated from the light source 3 is incident on the modulation device 4, and the intensity modulation is performed by the modulation device 4. The modulator 4 is driven by the modulation drive 10 to modulate the intensity of the light beam R for exposure to pass through. The modulation drive 10 is supplied with data through a data input device 11, a data processing device 12, a memory 13, and a data reading device 14.

Then, the intensity of light exposure R modulated by the modulation element 4 is incident on a deflection element (not shown) for the light beam R for exposure of the deflection element 5, and for this light beam R for exposure. The emission direction is deflected by passing through the deflection element. The deflection element for the film thickness measurement light beam M is deflected while maintaining a constant distance between the film thickness measurement light beam M and the exposure light beam R at the same time as the deflection element for the exposure light beam R. .

Then, the film thickness measurement light beam M generated from the optical head 25 is incident on a deflection element (not shown) for the film thickness measurement light beam M of the deflection element 5, and this film thickness The emission direction is deflected by passing through the deflection element for measuring light beam M. The deflection element for the film thickness measurement light beam M is deflected while maintaining a constant distance between the film thickness measurement light beam M and the exposure light beam R at the same time as the deflection element for the exposure light beam R.

The exposure light beam R and the film thickness measurement light beam M, which are deflected by the deflection element 5, are incident on the exit lens 2, are focused on the resist film 102 on the substrate 101, and are irradiated. do. The exposure light beam R irradiated onto the substrate 101 in this manner is deflected at a constant cycle and is intensity modulated in correspondence with the pattern drawn on the substrate 101.

Then, the XY controller 18 drives the moving stage 6 through the servo mechanisms 19, 20, 21, and 22, and is indicated by the arrow X and the arrow Y in FIG. The substrate 101, the drawing head 1, and the optical head 25 are relatively moved by moving in the horizontal direction at periodic intervals.

In this laser drawing apparatus, a raster scan drawing method similar to that of the first embodiment is used, and on the substrate 101, for example, inputted to the data input device 11 at a speed of about 300 mm &lt; 2 &gt; Drawing of a predetermined pattern is performed.

And this laser drawing apparatus is equipped with the film thickness measuring means which measures the film thickness of a resist film based on the reflection light beam of the film thickness measurement light beam M from the board | substrate 101 which is an exposure object. That is, the reflected light flux of the film thickness measuring light beam M from the substrate 101 is incident on the film thickness measuring circuit 24 serving as the film thickness measuring means through the exit lens 2 and the deflection element 5. . The film thickness measuring circuit 24 detects the amount of opposite light incident thereon and calculates the film thickness of the resist film 102 based on the detection result.

The reflected light amount of the light flux M for measuring the film thickness from the substrate 101 is an interference between the reflected light from the surface of the resist film 102 and the surface of the resist film 102, that is, the reflected light from the surface of the substrate 101. Fluctuates by That is, since the reflected light quantity value of the light flux M for measuring the film thickness from the substrate 101 becomes a function of the film thickness of the resist film 102, if the relationship between these reflected light quantity values and the film thickness is specified in advance, the reflection The film thickness of the resist film 102 can be known from the light amount detection result.

The film thickness value of the resist film 102 detected by the film thickness measurement circuit 24 is transmitted to the modulation drive 10. The modulation drive 10 corrects the modulation amount by the modulation element 4 based on the film thickness value of the resist film 102. That is, the modulator 4 modulates the intensity of the light beam R for exposure based on the drawing pattern set in advance and the measurement result by the film thickness measurement circuit 24.

In this laser drawing apparatus, the light flux M for measuring film thickness is scanned on the substrate 101 in advance of the light flux R for exposure. That is, on the board | substrate 101, the exposure light beam R is irradiated to the position to which the light beam M for film thickness measurement is irradiated after that. Therefore, the exposure light beam R is irradiated to the location where the film thickness of the resist film 102 to which the film thickness measurement light beam M was already irradiated was measured while the intensity was corrected based on this measurement result.

In addition, in this film thickness measuring light flux M, a high laser (for example, wavelength 500 nm or more) of the wavelength which is not exposed to a resist is used.

The interval between the irradiation position of the light flux R for exposure on the substrate 101 and the irradiation position of the light flux M for measuring the film thickness on the substrate 101 is preferably 10 mm or less. The correction value in the exposure light flux R based on the film thickness of the resist film 102 measured by irradiation of the light flux M for measuring the film thickness or the film thickness is the exposure light flux ( The interval until R) is irradiated and should be stored, but by narrowing the interval between the irradiation light beam R and the irradiation position on the film thickness measurement light beam M, the data that should be stored until the exposure light beam R is irradiated. This is because the amount can be reduced.

In this laser drawing apparatus, as shown in Fig. 5, the film thickness measuring light beam M is incident on the substrate 101 at an incidence angle of about 45 °, and the film thickness measuring light beam M The opposite luminous flux radiated | emitted from the board | substrate 101 at the exit angle of about 45 degrees may be made into the structure which directly injects into the film thickness measuring circuit 24.

In addition, the film thickness measurement of the resist film 102 by the film thickness measuring circuit 24 may be made between the film thickness measuring sections which do not write the predetermined drawing pattern in the board | substrate 101. FIG. In this case, in this laser drawing apparatus, as shown in the flowchart of FIG. 7, first, in step st11, in the film thickness measurement section of the substrate 101, the light quantity of the light beam opposite to the light flux M for measuring the film thickness is determined. Detect. This film thickness measurement section is, for example, in a section of about 10 μm.

In step st12, the film thickness of the resist film 102 is calculated based on the detected amount of light of the opposite luminous flux, the average value is calculated, and the result of the calculation is stored.

In step st 13, the film thickness of the resist film 102 calculated in step st12 is determined to be included in the predetermined range, and if included in the predetermined range, the process proceeds to step st14 and included in the predetermined range. If no, the process proceeds to step st16. Thus, the predetermined range of the film thickness of the resist film 102 is, for example, in the range of ± 2.5% to ± 5% of the specified film thickness.

In step st16, if it is determined that the resist film 102 of the substrate 101 is defective, a warning is issued indicating that it is defective. This warning is made, for example, by sounding a buzzing sound or by giving a predetermined indication.

In step st14, the correction value of the amount of light of the light flux R for exposure is determined based on the film thickness of the resist film 102 calculated in step st12.

In step st15, the exposure amount dose is corrected based on the correction value determined in step st14, drawing is performed, and step st11 is performed in this section.

As described above, in the present laser drawing apparatus, the film thickness measurement of the resist film 102 is repeated in the film thickness measurement section where the drawing is not advanced, and the drawing is performed by correcting the exposure amount based on the result of the film thickness measurement. Drawing of a predetermined drawing pattern is performed in order.

In addition, in the raster scanning method, as described above, when performing the scanning of the Y-direction scanning unit of the exposure light beam R and the movement of the X-direction transmission unit repeatedly, an integer number of film thickness measurement sections are performed in the Y-direction scanning unit. It is preferable to set so as to include. In the case of the single pass method, it is more preferable to set so as to include an integer number of film thickness measurement sections in the section excluding the overlap portion in the Y-direction scanning unit.

In the X-direction length of the film thickness measurement section, it is preferable to make it the same as the X-direction transmission unit corresponding to the beam diameter of the light beam R for exposure. In addition, when setting so that one film thickness measurement section may be included in the Y direction scanning unit or the area | region except the overlap part, two or more X direction transmission units may be used as a film thickness measurement period.

In this method, the deflection element 5 is set so that the exposure light beam R and the film thickness measurement light beam M each scan at least the Y-direction scanning unit.

In the laser drawing apparatus according to the present invention having such a configuration, the modulating means for modulating the intensity of the light beam for exposure irradiated by the drawing head with respect to the exposed object having the resist film formed on the surface portion is a preset drawing pattern and the exposed object. Since the intensity of the exposure light beam is modulated on the basis of the measurement result by the film thickness measuring means for measuring the film thickness of the resist film based on the light beam opposite to the light beam for exposure, the light beam is used in real time based on the light beam for exposure without using a dummy substrate. The film thickness of the resist film is measured and drawing is performed by the light beam for exposure.

Therefore, in this laser drawing apparatus, it is not necessary to perform the film thickness measurement work before drawing, and the time required for drawing work can be shortened. Moreover, in this laser drawing apparatus, since the film thickness of a resist film is measured using the light beam for exposure, it is not necessary to mount a separate laser light source, and structure can be simplified.

Moreover, in the laser drawing apparatus which concerns on this invention, the modulation means which modulates the intensity | strength of the exposure light beam irradiated by the drawing head with respect to the exposure object in which the resist film was formed in the surface part is a preset drawing pattern and the film thickness from an exposure object. Since the intensity of the exposure light beam is modulated on the basis of the measurement result by the film thickness measuring means for measuring the film thickness of the resist film based on the light beam opposite to the measurement light beam, in real time based on the light beam for exposure without using a dummy substrate. The film thickness of the resist film is measured and drawing is performed by the light beam for exposure.

Therefore, in this laser drawing apparatus, it is not necessary to perform the film thickness measurement work before drawing, and the time required for the drawing work can be shortened.

Moreover, in this laser drawing apparatus, the distance between the irradiation position of the exposure light beam in an exposure object and the irradiation position of the film thickness measurement light beam on an exposure object is made into 10 mm or less, and it places in the place where the drawing by the exposure light beam is performed. Accurate film thickness measurement of the resist film can be performed.

That is, the present invention does not reduce the productivity even when the exposure target formed on the surface of the resist film (photosensitive resin film) is large, such as a large photomask, and also the variation in the film thickness of the resist film in the minute region. It is possible to provide a laser drawing apparatus in which an optimal exposure dose is set, and even a drawing pattern including a fine pattern is not affected by the change in the film thickness of the resist film and can perform a good drawing pattern.

Claims (7)

A drawing head for irradiating a light beam for exposure to an exposure object having a resist film formed on a surface thereof; Scanning means for moving the irradiation position of the exposure light beam on the exposure object, Modulating means for modulating the intensity of the light beam for exposure, and Film thickness measuring means for measuring a film thickness of said resist film based on a light beam opposite to the light beam for exposure from said exposure object, And said modulating means modulates the intensity of said exposure luminous flux based on a preset drawing pattern and a measurement result by said film thickness measuring means. A drawing head which irradiates a light beam for exposure to an exposure object having a resist film formed on a surface thereof; An optical head for irradiating a light beam for measuring film thickness to the exposure object; Scanning means for moving the irradiation positions of the exposure light flux and the film thickness measurement light flux on the exposure object; Modulating means for modulating the intensity of the light beam for exposure, and Film thickness measuring means for measuring the film thickness of said resist film based on the light beam opposite to the light flux for measuring the film thickness from said exposure object, The film thickness measurement luminous flux is irradiated prior to the exposure luminous flux at the position where the exposure luminous flux is irradiated from the exposure object, And said modulating means modulates the intensity of said exposure luminous flux based on a preset drawing pattern and a measurement result by said film thickness measuring means. The method of claim 2, And a distance between the irradiation position of the exposure light beam on the exposure object and the irradiation position of the film thickness measurement light beam on the exposure object is 10 mm or less. The exposure light beam by the drawing head is irradiated to the exposure object in which the resist film was formed in the surface part, Moving the irradiation position of the exposure light beam on the exposure object, The film thickness of the resist film was measured based on the luminous flux opposite to the luminous flux from the exposure object, And an intensity of the exposure luminous flux is modulated based on a preset drawing pattern and a measurement result of the film thickness of the resist film. An exposure light beam is irradiated to the exposed object having a resist film formed on the surface by a drawing head, and the light flux for measuring film thickness is irradiated to the exposed object; The irradiation position of the exposure light flux and the film thickness measurement light flux on the exposure object is moved so that the film thickness measurement light flux is irradiated to the position to which the exposure light flux is irradiated prior to the exposure light flux on the exposure object. And The film thickness of the resist film was measured based on the luminous flux opposite to the luminous flux for measuring the film thickness from the exposure object, And a intensity of the exposure luminous flux is modulated based on a preset drawing pattern and a measurement result of the film thickness of the resist film. The light beam for exposure is irradiated to the photomask blank provided with the resist film in the surface part by the drawing head, Move the irradiation position of the exposure light beam on the photomask blank, The film thickness of the resist film is measured based on the luminous flux opposite to the luminous flux from the photomask blank, A method of manufacturing a photomask, characterized in that the intensity of the exposure light flux is modulated based on a preset drawing pattern and a measurement result of the film thickness of the resist film. The photomask blank having the resist film on the surface thereof is irradiated with an exposure light beam by a drawing head, and the photomask blank is irradiated with a film thickness measurement light beam, On the photomask blank, the irradiation positions of the exposure light flux and the film thickness measurement light flux on the photomask blank are irradiated to the position where the exposure light flux is irradiated prior to the exposure light flux. Moving it, The film thickness of the resist film was measured based on the luminous flux opposite to the luminous flux for measuring the film thickness from the photomask blank, A method of manufacturing a photomask, characterized in that the intensity of the exposure light flux is modulated based on a preset drawing pattern and a measurement result of the film thickness of the resist film.

Images