JP4247081B2 - Laser beam intensity monitoring method of laser annealing apparatus and laser annealing apparatus - Google Patents

Description

  The present invention relates to a laser beam intensity monitoring method used in a laser annealing apparatus for polycrystallizing an amorphous semiconductor film formed on a substrate by irradiating a laser, and the laser annealing apparatus.

  Laser annealing equipment uses a method of crystallizing the band corresponding to the irradiation beam width by scanning the irradiation site while irradiating the semiconductor film on the substrate, especially the silicon film, with the laser beam. A large surface area is polycrystallized by repeatedly scanning with a beam. In laser annealing, if the irradiation beam width is increased, the processing area speed can be increased and the productivity can be improved. However, there is a limit to the beam width that can be uniformly adjusted with a single laser optical system. Therefore, there is a method of arranging a plurality of sets of irradiation systems from a plurality of laser oscillators and corresponding laser optical systems, arranging irradiation beams from the respective optical systems close to each other, and simultaneously sweeping the semiconductor film surface. It's being used.

  In a conventional laser annealing apparatus using a plurality of laser beams, as shown in Patent Document 1, a substrate is irradiated with laser beams from a plurality of laser oscillators in parallel and scanned, so that a single pass is performed. Usually, it is possible to crystallize an irradiation width that is a multiple of a single beam width. In such a laser annealing method, it is relatively difficult to produce a large crystal grain size that is uniform over the entire irradiation width. One of the causes is that when the output of a plurality of irradiation laser beams fluctuates mutually, the crystal It is divided into a large particle size region and a small region. Therefore, in the transistor element formed over such a mixed region of fine and coarse crystal grains, the operation characteristics of the element vary depending on the formation location. For this reason, Patent Document 1 irradiates a plurality of laser beams from a plurality of laser oscillators via corresponding laser optical systems, and outputs laser beams to each laser beam optical system between the surface of the object to be irradiated. A power meter for measuring The irradiation beam intensity data from the power meter is monitored, and the beam output of each optical path is calibrated so that all the beam outputs are practically equal with the data for each optical system beam.

  Patent Document 2 discloses a laser annealing apparatus in which an irradiation laser beam from two or more optical systems is measured with a power meter immediately before irradiating a sample. The optical path between the system and the laser light source is provided with a shutter for opening and closing the optical path and a dimmer for adjusting the intensity, and the power meter is fixed on the side of the sample on the movable table. When measuring with this device, with the irradiation beam irradiated on the power meter, the optical system to be measured is sequentially selected by opening and closing the shutter provided for each optical path, the intensity is measured, and the light is dimmed. The intensity of the beam was measured with a device, and this was repeated for each optical path, so that a plurality of irradiation beams had a uniform intensity.

JP 2002-176007 A JP-A-2-119128

  It is convenient to arrange a power meter in each optical path of the laser optical system in order to grasp the energy irradiated to the substrate because the irradiation output can be constantly monitored for all irradiation beams.

  However, there is a measurement error in the data of each power meter, and the error is different for each power meter. When the power meter is calibrated or when the power meter is calibrated, the actual irradiation In this case, a deviation occurs between the output powers of the plurality of irradiation beams. Therefore, a precise and uniform power meter is required for each laser optical system.

  Furthermore, the laser annealing apparatus of Patent Document 2 described above is advantageous in that it can remove the individual differences of the measuring instrument in that the beam from a plurality of optical paths can be measured with a single power meter. In order to receive the irradiation beam, it is necessary that there is little measurement error over the entire light-receiving surface area of the power meter, and opening and closing several optical paths during measurement is due to blocking of the beam of each optical system. The passing operation gives thermal fluctuations to the optical system and changes the passing efficiency of the beam energy. Such transient instability accompanying the blocking / transmission of the optical system fluctuates the beam intensity of each optical path. Therefore, in a laser annealing apparatus using a plurality of laser light sources, an irradiation beam having a narrow width is used. However, it is inevitable that the intensity distribution becomes uneven in the longitudinal direction.

  In view of the above problems, the present invention provides a laser capable of reducing as much as possible an intensity deviation between irradiation beams of a laser optical system caused by errors between intensity measuring instruments and thermal instability of the laser optical system. It is an object of the present invention to provide a monitoring method for an annealing apparatus and a laser annealing apparatus to reduce a difference in crystal grain size and other characteristics between irradiated regions on a semiconductor film.

  The laser beam intensity monitoring method of the present invention uses a single intensity measuring unit for the optical paths of a plurality of optical systems. The feature is that one intensity measuring unit is moved on the optical path of each optical system. In this way, each of the optical paths is positioned so as to be able to receive light, and the irradiation energy of each optical path is measured by a single intensity measuring unit for a plurality of laser optical systems.

  The apparatus of the present invention includes a plurality of laser light sources and a laser optical system corresponding to each laser light source, and irradiates a film material to be processed with an irradiation beam from each laser optical system in a region close to each other. The laser annealing device heat-treats the processed film material. Its features are a single intensity measurement unit that measures the laser beam intensity of each optical system, and the intensity measurement unit that can be moved across multiple optical paths. A moving mechanism.

  In the present invention, the irradiation beam from a plurality of laser optical systems is measured with a single laser beam intensity measurement unit, and therefore power caused by individual differences in the measuring instrument and differences in calibration when a plurality of intensity measurement units are used. During measurement, it is not necessary to block the beam for all the optical paths, so the optical system transmits the beam and is in a thermally steady state, which is caused by fluctuations in the optical system. Can eliminate the thermal error.

  Therefore, according to the present invention, it is possible to adjust a plurality of irradiation beams to a uniform output with little relative error between the beams, and using the laser annealing apparatus of the present invention, an irradiated film material, particularly an amorphous film. When a porous semiconductor film is irradiated and annealed, there is an advantage that it is possible to prepare a polycrystalline film having a uniform grain size in which the difference in crystal grain size between a plurality of bands as described above is reduced.

  Furthermore, a single intensity measuring unit required for the optical paths of a plurality of laser beam optical systems can be used, which is effective in terms of the arrangement of measuring instruments and the cost of maintenance calibration.

In the laser beam intensity monitoring method of the present invention, a film material to be processed is heated by irradiating a film material to be processed in a region close to each other with a plurality of laser optical systems. a laser annealing equipment, the laser beam intensity monitor method, a laser beam intensity of each optical system, which measures each by a single intensity measurement section movably disposed over the plurality of optical paths.

  The laser annealing apparatus of the present invention includes a plurality of laser light sources and a laser optical system corresponding to each laser light source, and irradiates a film material to be processed with an irradiation beam from each laser optical system in areas close to each other. The material to be processed is heat-treated, and the feature thereof is that a single intensity measuring unit for measuring the laser beam intensity of each optical system and the intensity measuring unit are arranged to be movable over a plurality of optical paths. And a moving mechanism.

  In the present invention, this preferable mode includes that the intensity measurement unit is placed at a position retracted from any optical path and moves so as to receive and directly measure the beam of each optical path at the time of measurement.

  In another form, a partial transmission / reflection mirror that splits the laser beam into a partial beam outside the optical path is preferably disposed in each optical path, and the intensity measurement unit transmits or reflects from the partial transmission / reflection mirror. It is preferable to be movable so that the partial beam is received and measured.

  In this configuration, a partial transmission mirror is arranged in each optical path of the laser beam optical system, and the partial beam that has passed through the mirror is sequentially measured as the single intensity measurement unit moves, and laser beam irradiation is continued. However, there is an advantage that the intensity of the laser beam can be measured for the entire optical system.

  In order to make the single intensity measurement unit movable, a movement mechanism, for example, a slide mechanism is provided, and the movement mechanism sequentially moves to each optical path across the optical paths of a plurality of laser beams to be received. It is possible to adopt one that positions the light receiving surface. In this way, by coupling the intensity measurement unit to a moving mechanism, for example, a slide mechanism, the intensity measurement unit can be moved on the optical path of each laser beam optical system. Thereby, the irradiation energy can be measured over a plurality of laser beam optical systems with only one intensity measuring unit.

  The single intensity measuring unit can measure the intensity of the irradiation beam applied to the film material to be processed by being arranged in the optical path between the optical system and the material to be processed. Since the irradiation beams from all the optical systems can be measured accurately, for example, by adjusting the variable attenuator provided in each optical and measuring the intensity again with this measurement signal or measurement data, a plurality of repetitions are made. The intensity of the irradiation beam can be set to be substantially the same.

  In another embodiment, the intensity measuring unit is a first intensity measuring unit, and a second single intensity measuring unit is arranged at a position different from the first intensity measuring unit in the optical path of the optical system. Measuring the laser beam intensity for each optical path. The first single intensity measuring unit and the second intensity measuring unit can be separately moved over the corresponding optical paths, and are positioned so as to be able to receive light for each optical path, as described above.

  In this way, by arranging two single intensity measuring units with different optical path positions, it is possible to measure several beam generation sites by dividing several occurrence sites with large intensity fluctuations. From this, it is possible to know and adjust the intensity fluctuation at the generation site.

  In such a measurement mode, the first intensity measurement unit is disposed in the optical path between the optical system and the film material to be processed, and the intensity of the irradiation beam irradiated to the film material to be processed is measured. The second single intensity measuring unit can be arranged in the optical path between the laser oscillator and the optical system to measure the intensity of the laser beam emitted from the laser oscillator.

  The monitoring method of this example uses two sets of intensity measuring units, and can measure the optical element transmission efficiency between the laser oscillator and the stage from the difference in intensity, and each optical element can be monitored by monitoring the optical element transmission efficiency. Abnormalities of elements and devices can be determined. Further, each oscillator is adjusted by the intensity data of the second single intensity measuring unit so that the output of the oscillator becomes constant, and then the data of the first single intensity measuring unit is used for the data of each optical system. The irradiation beam intensity can be known. In this case, as will be described later, a variable attenuator can be adjusted with the data of the first single intensity measuring unit by inserting a variable attenuator between each of the plurality of laser oscillators and the optical system. Thus, the intensity of the irradiation beam from each optical system can be adjusted to be substantially the same for all optical systems.

  Further, in each optical path of the laser optical system, the output of the laser oscillator is measured by the second intensity measuring unit via the partially transmitting mirror or the partially reflecting mirror, and the optical power is measured by the first single intensity measuring unit. By measuring the laser beam intensity after passing through the element, it is possible to determine the abnormality of each optical element and device by monitoring the optical element transmission efficiency while performing laser beam irradiation during the annealing operation. Further, as will be described later, the intensity of the irradiation beam can be arbitrarily adjusted by arranging and adjusting a variable attenuator.

  According to another aspect of the present invention, the laser annealing apparatus receives each variable optical attenuator disposed between each laser optical system and the corresponding laser light source, and an intensity signal from the intensity measuring unit, It is preferable to include a feedback control unit that controls the attenuation rate of each attenuator by supplying a control signal to the drive unit of the variable attenuator. By this control unit, the attenuation characteristic of each optical path is adjusted and the attenuation characteristic is adjusted. Adjusting within a predetermined range.

  Further, in this embodiment, a single intensity measurement unit is arranged in the optical path between the variable attenuator and the optical system, and the feedback control unit uses the measurement signal from the intensity measurement site to change the variable attenuation between the optical paths. Calibrating the vessel.

  Further, each laser oscillator may be provided with an oscillation intensity measurement unit. In this case, feedback control is performed using an oscillation intensity signal from the oscillation intensity measurement unit and an intensity measurement signal from the single intensity measurement unit. The unit controls each attenuator, so that the irradiation beam intensity between the optical paths can be controlled to be constant.

  Another aspect of the monitoring method and annealing apparatus including the feedback control unit is to automatically control the intensity of the laser beam using the measurement value under the single intensity measurement unit, and the feedback control unit (or storage device) ) Set and store the required beam intensity at the measurement site in advance, compare the intensity measurement signal from the single intensity measurement unit with the set intensity, and use the comparison signal as a control signal, and a variable attenuator (Or a drive unit that drives the variable attenuator and variably adjusts the attenuation amount), adjusts the amount of reduction of the variable attenuator, and matches the measured intensity of the single intensity measurement unit with the set intensity Thus, it is preferable to perform closed loop control. As a result, in the measurement by the single intensity measuring unit, there is an advantage that all the beam intensities of the measurement parts for all the optical systems can be automatically and automatically adjusted to the preset unified intensity. is there.

In these embodiments, a gas laser or a solid-state laser can be used as the laser light source. In particular, the laser output of a solid laser may fluctuate due to thermal lens curing in an oscillator, and the present invention can be preferably applied to a solid laser.
When a silicon film is used as a material to be processed, an amorphous silicon film formed on a substrate adjusts a polycrystalline silicon film by laser processing. Thus, when the film material is silicon, visible light having a wavelength of 330 to 800 nm has an appropriate absorption performance with respect to the silicon film and is widely used as the laser light source. These laser light sources include Nd: YAG laser second harmonic or third harmonic, Nd: glass laser second harmonic or third harmonic, Nd: YVO ₄ laser second harmonic or third harmonic. Harmonic, second harmonic or third harmonic of Nd: YLF laser, Yb: second harmonic or third harmonic of YAG laser, Yb: second harmonic or third harmonic of glass laser, or A fundamental wave or second harmonic of a Ti: Al ₂ O ₃ laser can be used.
In the present invention, as a laser light source, in addition to the above harmonics of the solid-state laser, a gas laser, for example, a CO ₂ laser, may be used to heat a wide area by arranging a plurality of gas lasers. it can.

  As the intensity measurement unit, a power meter such as a calorimeter is used because the laser annealing apparatus has a large irradiation energy. The following embodiments will be described with examples of power meters.

Embodiment 1 FIG.
In this embodiment, a single power meter is arranged so as to be movable between optical paths in an optical path between an optical system and a substrate as an irradiation surface, and a beam in the optical path is directly measured. When the apparatus is in operation, the power meter can be placed at a place where it is retracted from these optical paths. In this case, the irradiation beam can be transmitted so that the optical path can be irradiated. On the other hand, at the time of measurement, the power meter sequentially blocks each optical path, receives the beam from the optical path at its light receiving surface, and measures its intensity. For this purpose, the power meter is fixed on the moving device so as to cross a plurality of optical paths, and the power meter is moved by the moving device so as to be able to receive light in each optical path in a desired order. The measured intensity data is used to adjust an optical component that can control the intensity of the optical path. Since this embodiment measures the intensity between the optical system of the optical path and the irradiation surface, there is an advantage that the intensity of the irradiation beam directly incident on the substrate can be accurately adjusted.

In the example shown in FIG. 1, as a laser light source, a plurality of laser oscillators 1 (in this example, three solid-state laser oscillators 1a, 1b, and 1c) and intensity adjustment of laser beams 20a, 20b, and 20c from the respective laser oscillators are used. Attenuator 2 (similarly, three attenuators 2a, 2b, and 2c) and optically operating upon receiving the laser beam from each attenuator, and a line on an irradiation surface that is a semiconductor film on substrate 7 It comprises laser optical systems 3 and 4 for supplying an irradiation beam as a beam profile, and a two-dimensional movable stage 11 on which a substrate 7 carrying a semiconductor film forming an irradiation surface is mounted.

Each of the laser beam optical systems 3 and 4 is a homogenizer 3 (for example, three homogenizers 3a, 3b, and 3c) for uniformizing the intensity distribution of the laser beam emitted from the laser oscillator 1 and passed through the attenuator 2. And a transmission system 4 that receives the laser beam and converges and irradiates it on the substrate 7.

Although not shown, the optical systems 3 and 4 in this example include a waveguide having reflection surfaces facing each other in the y direction and a transfer lens that transfers the waveguide exit end surface onto the substrate only in the y direction. wherein, while the transmission system 4, this example comprises a pair of cylindrical lenses 4 a to 4 c, by condensing on the substrate only in the x direction of the transfer beam from the homogenizer 3, as a result, the substrate 7 on The irradiation surface is long in the y direction and very narrow in the x direction, and a linear irradiation beam is formed at the irradiation portion 22 (for example, three irradiation portions 22a, 22b, and 22c) .

  In this embodiment, the power meter 5 is disposed between the plurality of laser beam optical systems and the irradiation surface on the substrate 7 so as to be able to receive light while blocking the optical path.

  Although this example is not shown in the figure, a power meter 5 is mounted on a slide that includes a guide orthogonal to the optical path, and moves along the guide, with its light receiving surface directed toward the optical system of the optical path. The slide table is automatically controlled to reciprocate. Usually, a fixed position for fixing the slide base is provided as appropriate, and the fixed position may be a position where the power meter 5 does not obstruct any optical path, and the power meter 5 is positioned when the annealing apparatus is in operation. Has been placed in

  At the time of measurement, the annealing process of the device is interrupted, but the slide base is moved by selecting the optical system to be measured in advance or appropriately or specifying it sequentially while the laser oscillator is still operating. The power meter 5 is accurately positioned so as to receive light in the optical path, and the energy intensity of the optical path is accurately measured by the power meter 5. Next, the power meter 5 moves to the designated optical path and measures the energy intensity of the optical path. By repeating the movement and measurement, the measurement data can be obtained by measuring the intensity of the irradiation beam for the entire optical system.

  One method of adjusting the beam intensity from the measurement data is to determine a correction value for each optical path from the measured intensity data of all the optical paths so that the intensity of all the optical paths is substantially the same. From the value, the variable attenuator 2 of each optical path is adjusted so that the beam intensities of all the optical paths are substantially the same. During or after this adjustment, the strength is measured again according to the above procedure to confirm that uniform strength has been achieved.

  In another method, intensity measurement is performed for each optical path, and the variable attenuator 2 is adjusted on the spot so that the measured value becomes a predetermined set value. This operation is performed for all the optical systems. Thereby, finally, substantially the same intensity can be obtained for all the optical paths.

Embodiment 2. FIG.
In this embodiment, a first intensity measurement unit is provided between a plurality of optical systems and an irradiation surface of a corresponding substrate, and a second single intensity measurement unit is arranged between the laser oscillator and the attenuator. Thus, two-stage measurement is performed.

  As in the first embodiment, the first intensity measurement unit measures each optical path between each optical system and the irradiation surface of the corresponding substrate with a single measurement unit, adjusts the attenuator, The intensity of the irradiation beam in the optical path is made uniform.

  The second intensity measurement unit is arranged between the laser oscillator and the attenuator, measures the radiation intensity of each laser oscillator, examines the difference in characteristics of each laser oscillator, and adjusts each laser oscillator to adjust each oscillation. The output is made uniform.

  The two-stage intensity measurement unit can determine whether the output fluctuation is caused by the laser oscillator or the optical element of the optical system. If a large output difference occurs, the cause Can be grasped quickly.

FIG. 2 shows this embodiment. In addition to the first embodiment, a laser oscillator 1 that outputs laser beams 20a, 20b, and 20c and an attenuator 2 that adjusts the laser beam intensity in the laser optical system are shown. A second power meter 8 is disposed between them.

  The first power meter 5 measures the output of the laser beam that has passed through each optical element and device, and the second power meter 8 measures the output of only the laser oscillator, and the substrate on the stage 11 from the laser oscillator 1. It is possible to grasp the transmission efficiency up to 7. As a result, in the optical elements and devices such as the attenuator 2, the homogenizer 3, and the beam transmission system 4 disposed after the laser oscillator, some abnormality (for example, damage to the reflection mirror in the attenuator or the lens in the beam transmission system). If the transmission efficiency measured by the power meter 5 and the power meter 8 is monitored, an abnormality in each optical element and apparatus can be determined.

Embodiment 3 FIG.
In this embodiment, a partial transmission mirror is inserted in each optical path from each laser oscillator to the substrate, a part of the laser beam is branched to the partial transmission mirror outside the optical path, and the partial beam is extracted. It is a thing measured by the intensity | strength measurement part. The power meter is disposed so as to move perpendicular to the optical path of the branched beam, and the energy intensity is measured by appropriately or sequentially measuring the plurality of branched beams with the power meter. By keeping the transmittance of the partial transmission mirror inserted in each optical path constant, it is possible to accurately know the intensity of the irradiation beam from the measured value.

In this example, as shown in FIG. 3, each laser beam emitted from a plurality of laser oscillators 1 (three laser oscillators 1a, 1b, 1c in the figure) is a laser beam as in the above embodiment. The laser beam intensity distribution is made uniform through a homogenizer 3 (3a, 3b, 3c) which is adjusted to a required intensity by a variable attenuator 2 (2a, 2b, 2c) for adjusting the intensity and uniformizes the laser beam intensity distribution. Turn into. Each laser beam from each homogenizer 3 is condensed on the substrate 7 by the beam transmission system 4 and is linearly profiled. Each irradiation beam 21 (21a, 21b, 21c) from the beam transmission system 4 is Most of the light is reflected and irradiated onto the substrate 7 on the stage 10 by the partial transmission mirrors 9 (9a, 9b, 9c) arranged after each beam transmission system 4.

One power meter 5 is arranged in the transmission direction of the partial transmission mirror 9 , and the power meter 5 is arranged so that the partial beam of the branched optical path transmitted through each partial transmission mirror 9 can be orthogonally moved so as to receive light. Yes.

  Here, the partial transmission mirror 9 transmits a certain percentage of the laser beam intensity from each beam transmission system 4, reflects the remaining light, and irradiates the substrate 7. The accurate transmittance of the partial transmission mirror is actually measured and known, and a part of the beam intensity of the irradiation beam 21 becomes transmitted light, and the intensity is measured by the power meter 5 disposed at the rear of the partial transmission mirror 5. . By dividing the measured intensity value by the power meter 5 by the known transmittance, the output of the irradiation beam can be known.

  In this embodiment, since the laser beam transmitted to the outside of the optical path is measured by the partial transmission mirror 9, there is an advantage that the power can be always measured without blocking the optical path with a power meter when measuring the beam intensity. In other words, the beam intensity can be measured at any time while performing the annealing process with the irradiation beam 21, so that there is an advantage that the productivity is not impaired. Further, since the power meter is provided with a movable mechanism such as a slide mechanism (not shown), there is an advantage that a single power meter may be used across a plurality of laser optical systems.

Embodiment 4 FIG.
As shown in FIG. 4, the apparatus of this embodiment attenuates laser beams output from a plurality of laser oscillators 1 (1a, 1b, 1c) through a second partial reflecting mirror 91 (91a, 91b, 91c). The beam guided to the device 2 (2a, 2b, 2c) and passed through the attenuator 2 is the homogenizer 3, the beam transmission system 4, and the partial transmission mirror 9 (9a, 9a, 9b, 9c) and reflected on the substrate 7, and the partial transmission mirror 9 transmits a few percent of the beam intensity from the beam transmission system 4 and is measured by the movable intensity measuring unit. .

The laser beam from the laser oscillator 1 passes through a partial reflecting mirror 91 (91a, 91b, 91c) that reflects several percent, and is adjusted to a required intensity by an attenuator 2 having means for adjusting the laser beam intensity. The homogenizer 3 provided with a means for making the laser beam intensity distribution uniform makes the laser beam intensity distribution uniform. Then, the beam is converted into a predetermined size by the beam transmission system 4, and then folded back onto the stage 11 by the partial transmission mirror 9 that transmits several percent, and is irradiated onto the substrate 7. When the laser beam passes through the partial reflection mirror 91 , several percent of the laser beam is reflected, and the laser beam intensity is measured by the power meter 8 arranged below the partial reflection mirror. Further, the partial beam that has transmitted several percent through the partial transmission mirror 9 is measured by the power meter 5 disposed at the rear of the partial transmission mirror, and an intensity signal of the laser beam can be obtained.

  From the results measured with the two power meters 5 and 8, it becomes possible to measure and manage the transmission efficiency of the optical system. If the transmission efficiency is monitored, it is possible to determine an abnormality in each optical element and device. it can.

Embodiment 5 FIG.
In this embodiment, a single power meter that can be measured by moving to each optical path of a plurality of laser beam optical systems or branched optical paths is arranged, and a detection signal from the power meter is transmitted to a food back control system. Thus, the output of each laser beam is controlled to control the output of the plurality of irradiation beams within a certain range.

  The feedback control unit outputs a control signal to control the laser oscillator and / or the attenuator, thereby both the intensity of the laser beam of the oscillator and / or the intensity of the beam that has passed through the attenuator, Includes one that is held constant over a plurality of optical systems.

In the example of FIG. 5, each of the laser optical systems 3 and 4 has an attenuation in which the laser beams 20a, 20b, and 20c output from the laser oscillator 1 (1a, 1b, and 1c) have means for adjusting the laser beam intensity. The laser beam intensity distribution is made uniform by the homogenizer 3 (3a, 3b, 3c) which is adjusted to the required intensity by the device 2 (2a, 2b, 2c) and has means for making the laser beam intensity distribution uniform. The beam is irradiated onto the substrate by the beam transmission system 4. A single power meter 5 is disposed in the optical path between the attenuator 2 and the homogenizer 3 for adjusting the laser beam intensity. The single power meter 5 can be moved on each laser beam optical path by a slide mechanism (not shown). The power meter 5 measures the output of the laser beam that has passed through the attenuators 2, and controls the transmittance of the attenuators 2 through the feedback control unit based on the output of the laser beam, thereby passing through the plurality of attenuators 2. The beam intensity is automatically adjusted so as to be at substantially the same level. Thereby , the transmission efficiency from the laser oscillator to the stage can be adjusted to be constant.

In FIG. 6, the feedback control system sets the laser beam irradiation state in step 1, and in step 2, the passing beam intensity of the attenuator 2 is measured by the power meter 5 of the slide mechanism in the optical path of each optical system. In step 3, in the feedback control system, the transmission data of the attenuator connected to each optical system is grasped from the measurement data.

  FIG. 7 is a graph showing an example of the transmittance characteristic of the attenuator. As can be seen from FIG. 7, in a plurality of optical systems, the transmittance characteristic of each attenuator (that is, the nominal transmission of the attenuator). Rate and the ratio of the actual energy transmitted through the attenuator to the ratio of the output to the input).

  When the difference in transmittance characteristics examined in step 3 (difference in relative beam output between the attenuators at the nominal transmittance, hereinafter the same) is greater than ± 1%, step 4 is performed between the attenuators. Each attenuator transmission characteristic is calibrated from the transmission characteristic difference data. By calibrating the transmittance between the attenuators, the transmittance characteristics between the attenuators of each optical system can be made substantially the same.

  Since each attenuator changes temperature and transmittance changes due to laser transmission for a long time, each attenuator periodically, for example, every product rod or every fixed time (for example, 24 hours) Transmittance calibration can be performed on the attenuator.

Embodiment 6 FIG.
In this embodiment, as shown in the example of FIG. 8, for each optical system, a single power meter 5 is directly connected to each optical path between the attenuator 2 and the optical systems 3 and 4, and the optical path is blocked. A feedback control unit 6 is provided so as to be movable so as to receive light, and the measurement signal of the power meter 5 drives and controls the attenuators 2a, 2b and 2c. Further, the laser oscillator 1 (1a, 1b, 1c) oscillating power meter 10 in (10a, 10b, 10c) has a built-in, respectively, to measure the output of the laser oscillator, the feedback control of the output signal Input to part 6. In this example, the oscillation output of each oscillator is constantly measured, and the feedback control unit 6 is configured so that the output of the laser beam passing from each laser oscillator 1 through the attenuator 2 is the same in any optical system. The attenuator 2 is feedback controlled.

Thus, by adjusting the transmittance of the attenuator for the output fluctuation from the laser oscillator, the irradiation beam 21 (21a, 21b, 21c) is stably irradiated onto the substrate 7 with substantially the same intensity. Can do.

  The monitoring method and laser annealing apparatus according to the present invention are used in the field of semiconductor manufacturing, particularly in the manufacturing field in which an amorphous silicon film deposited on a large substrate is irradiated with a laser beam to be polycrystallized, and the polycrystalline silicon. A transistor circuit is formed on the film and can be widely applied to the integrated circuit manufacturing field.

1 shows a schematic diagram of a laser annealing apparatus according to an embodiment of the present invention. The same figure as FIG. 1 of the laser annealing apparatus which concerns on another Example of this invention. The typical perspective view which shows the outline | summary of the laser annealing apparatus of another Example of this invention. The same figure as FIG. 3 of the laser annealing apparatus of another Example of this invention. The schematic diagram of the laser annealing apparatus of another Example of this invention. The flowchart figure which shows the attenuator calibration procedure of a laser annealing apparatus in another Example of this invention. The graph which shows the difference in the transmission characteristic between the attenuators used for the laser annealing apparatus in another Example of this invention. The schematic diagram of the laser annealing apparatus concerning another example of the present invention.

Explanation of symbols

1 laser oscillator, 2 attenuator, 3 homogenizer, 4 transmission system, 5 power meter, 6 feedback control unit, 7 substrate, 11 stage, 9 power meter.

Claims (19)

  In a laser beam intensity monitoring method of a laser annealing apparatus that includes a plurality of laser optical systems and irradiates a processing target film material with irradiation beams from each laser optical system in a region close to each other, and heats the processing target film material A laser beam intensity monitoring method for a laser annealing apparatus, wherein the laser beam intensity of each optical system is measured by a single intensity measuring unit arranged so as to be movable over a plurality of optical paths. The single intensity measuring unit is installed at a position retracted from any optical path, and includes a movable part so as to receive and directly measure the beam of each optical path at the time of measurement. The method described. In a laser beam intensity monitoring method of a laser annealing apparatus that includes a plurality of laser optical systems and irradiates a processing target film material with irradiation beams from each laser optical system in a region close to each other, and heats the processing target film material In each optical path of each optical system, a partial reflecting mirror that divides the laser beam into partial beams is arranged outside the optical path, and is arranged so as to be movable so as to receive and measure the partial beams branched by the partial reflecting mirror. A laser beam intensity monitoring method, wherein the intensity of each partial beam is measured by a single intensity measuring unit.   4. The method according to claim 1, wherein the single intensity measuring unit can be positioned on a beam to be received by a moving mechanism. The single intensity measuring unit, disposed in an optical path between the optical system and the processing film material, according to claim 1 or 2 for measuring the intensity of each illumination beam irradiated on the processed film material the method of. The single intensity measuring unit includes a first intensity measuring unit provided in the optical path of the optical system, and a second intensity measuring unit arranged at a position different from the first intensity measuring unit, 3. The method according to claim 1 , wherein the intensity measuring unit measures the laser beam intensity at different positions on the optical path. The single intensity measuring unit includes a first intensity measuring unit provided in the optical path between the optical system and the film material to be processed, and a laser beam partially out of the optical path between the laser oscillator and the optical system. And a second intensity measuring unit arranged to receive and measure the partial beam branched by the partial reflector , the second intensity measuring unit arranged to split the beam into the beam ,
The first intensity measurement unit measures the intensity of the irradiation beam irradiated to the film material to be processed,
The method according to claim 1 , wherein the second intensity measuring unit measures the intensity of the laser beam emitted from the laser oscillator. The laser annealing apparatus includes a variable attenuator disposed between each laser optical system and the corresponding laser light source, and an intensity signal from the single intensity measuring unit, and a driving unit for each variable attenuator. 3. A feedback control unit for controlling the attenuation rate of each attenuator by supplying a control signal to the attenuator, and adjusting the attenuation characteristic of the attenuator of each optical path within a predetermined range. The method described in 1. The single intensity measurement unit is disposed in the optical path between the variable attenuator and the optical system, and the feedback control unit uses the measurement signal from the single intensity measurement unit to change the variable attenuation between the optical paths. 9. A method according to claim 8, wherein the vessel is calibrated.   Each laser oscillator has an oscillation intensity measuring unit, and the feedback control unit controls each attenuator by the oscillation intensity signal from the oscillation intensity measuring unit and the intensity signal from the single intensity measuring unit, and the optical path The method according to claim 9, wherein the irradiation beam intensity is controlled to be constant. A plurality of laser light sources and a laser optical system corresponding to each laser light source are provided, and the processing target film material is heated by irradiating the processing target film material with the irradiation beam from each laser optical system in a region close to each other. In the laser annealing equipment to
The apparatus includes a single intensity measuring unit that measures the laser beam intensity of each optical system, and a moving mechanism in which the intensity measuring unit is arranged to be movable over a plurality of optical paths.
The laser annealing apparatus, wherein the single intensity measuring unit measures the laser beam intensity of each optical system by moving it over a plurality of optical paths.   The apparatus according to claim 11, wherein the moving mechanism includes placing the intensity measuring unit at a position retracted from any optical path, and moving the optical measurement unit so as to receive and directly measure the beam of each optical path during measurement. . A plurality of laser light sources and a laser optical system corresponding to each laser light source are provided, and the processing target film material is heated by irradiating the processing target film material with the irradiation beam from each laser optical system in a region close to each other. In the laser annealing equipment to
A single intensity measurement unit for measuring the laser beam intensity of each optical system;
A moving mechanism in which the intensity measuring unit is movably disposed across a plurality of optical paths;
A partial reflecting mirror disposed in each optical path of each optical system and branching the laser beam into a partial beam outside the optical path;
The laser annealing apparatus, wherein the moving mechanism moves the intensity measuring unit so that the intensity measuring unit receives the partial beam branched by the partial reflecting mirror and measures the intensity.   The single intensity measuring unit is disposed in an optical path between a laser optical system and a film material to be processed, and measures the intensity of an irradiation beam irradiated to the film material to be processed. apparatus. The single intensity measuring unit includes a first intensity measuring unit arranged in the optical path of the optical system, and a second intensity measuring unit arranged at a position different from the first intensity measuring unit on the optical path. The apparatus according to claim 11 or 12 , wherein each intensity measuring unit measures the laser beam intensity at a different position on the optical path. The single intensity measuring unit includes a first intensity measuring unit provided in the optical path between the optical system and the film material to be processed, and a laser beam partially out of the optical path between the laser oscillator and the optical system. And a second intensity measuring unit arranged to receive and measure the partial beam branched by the partial reflector , the second intensity measuring unit arranged to split the beam into the beam ,
The first intensity measurement unit measures the intensity of the irradiation beam irradiated to the film material to be processed,
The apparatus according to claim 11 or 12 , wherein the second intensity measuring unit measures the intensity of a laser beam emitted from a laser oscillator. The laser annealing apparatus receives each of the variable attenuators disposed between each laser optical system and the corresponding laser light source, and receives the intensity signal from the single intensity measuring unit, and drives the variable attenuator. by supplying a control signal to include a feedback control unit for controlling the attenuation factor of the attenuator to claim 11 or 12, characterized in that to adjust the damping characteristics of the attenuator of each optical path within a predetermined range The device described. The single intensity measurement unit is disposed in the optical path between the variable attenuator and the optical system, and the feedback control unit uses the measurement signal from the single intensity measurement unit to change the variable attenuation between the optical paths. The apparatus of claim 17, wherein the apparatus is calibrated.   Each laser oscillator has an oscillation intensity measuring unit, and the feedback control unit controls each attenuator by the oscillation intensity signal from the oscillation intensity measuring unit and the intensity signal from the single intensity measuring unit, and the optical path 19. The apparatus according to claim 18, wherein the intensity of the irradiation beam is controlled to be constant.

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