JP2004035987A - Laser thin film forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a low-cost and a long-life laser thin film forming device capable of uniformly forming the thin film in large area. <P>SOLUTION: A raw material gas is photolyzed by making laser beam incident in a chamber to deposit the thin film S on a substrate 94. A light-emitting part 68 of a laser light source is arranged in line shape along the width direction of the substrate 94. The laser beam is condensed in line shape to the width direction of the substrate 94 by a collimator lens 128 and a cylindrical lens 104 and the beam is irradiated in the form of line beam. Therefore, it is not required to scan the line beam and the thin film is uniformly formed on the whole surface only by moving a moving stage 96 to the arrow A direction. The low-cost and long-life light source is obtained by using a group III nitride based semiconductor laser as the laser light source. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser thin film forming apparatus in which a laser beam is incident on a source gas or a solid material in a closed space, and a thin film is deposited on a substrate housed in the closed space by a product obtained by decomposition and synthesis reaction.
[0002]
[Prior art]
Among laser deposition methods, there is a method of depositing a thin film on a substrate using decomposition and reaction of a source gas or a solid material by a laser beam.
[0003]
A thin film formation method by CVD (Chemical Vapor Deposition) is a method in which a laser beam is incident into a closed chamber, the source gas supplied into the chamber is decomposed by light energy, and the thin film is formed into a substrate. In the thin film formation method by laser sputtering, a laser beam is incident into a closed chamber, and the solid material in the chamber is irradiated to vaporize the solid material. It is deposited on the substrate.
[0004]
Thus, by using a laser as excitation energy, the temperature of the substrate that is the target of film formation does not increase compared to other PVD (evaporation / sputtering, etc.) and CVD (heat, plasma, etc.). Since a thin film with low stress can be formed, warping can be reduced particularly in the case of a large-sized substrate.
[0005]
Incidentally, as shown in FIG. 13, in the conventional thin film formation method, an ArF excimer laser 140 having a wavelength of about 193 nm has been used.
[0006]
The ArF excimer laser 140 has a problem that the pulse width is constant and a particle size having desired physical properties cannot be obtained. In addition, since the ArF excimer laser 140 has a slow pulse drive repetition frequency of 2 kHz, it takes time to accumulate energy, the film formation rate is slow, and the production efficiency is not good.
[0007]
Furthermore, the ArF excimer laser 140 is expensive, its life is as short as about 5 × 10 ⁷ shots, and the running cost is high.
[0008]
The conventional laser / sputtered thin film forming apparatus forms a thin film in the width direction (A direction) of the substrate 94 by deflecting a laser beam emitted from a single ArF excimer laser 140 by an optical scanning system 142. In the vertical direction (B direction), the film was formed by moving the stage 144 on which the substrate 94 was placed.
[0009]
For this reason, it could not be used for forming a thin film of a product having a large film formation area, such as a Si-TFT for liquid crystal and a solar cell.
[0010]
[Problems to be solved by the invention]
In consideration of the above facts, an object of the present invention is to provide a laser thin film forming apparatus that can uniformly form a large area and has a low cost and a long lifetime.
[0011]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a laser thin film forming apparatus in which a laser beam is incident into a reaction vessel, a source gas supplied into the reaction vessel is photodecomposed, and a thin film is deposited on a substrate. A laser light source configured to generate a plurality of light emitting points by a laser, and an optical system that focuses a laser beam emitted from the laser light source in a line shape in the width direction of the substrate. Yes.
[0012]
In the first aspect of the present invention, a laser beam is incident into the reaction vessel, the source gas supplied into the reaction vessel is photodecomposed, and a thin film is deposited on the substrate.
[0013]
Here, the laser light source is configured to generate a plurality of light emission points, and the light emission points are arranged in a line along the width direction of the substrate. This laser beam is condensed in a line shape in the width direction of the substrate by the optical system, and is irradiated as a line beam extending in the width direction of the substrate.
[0014]
For this reason, it is not necessary to move the substrate in the width direction of the substrate or to scan the laser beam as in the case of a conventional laser beam of a single light source. Since it is only necessary to move the substrate or scan the line beam, the apparatus configuration is not complicated. In addition, since the range of film formation at a time is large, it is suitable for forming a thin film of a product having a large film formation area.
[0015]
According to a second aspect of the present invention, there is provided a moving stage on which the substrate is placed and is movable in a direction orthogonal to the width direction of the substrate.
[0016]
In the invention according to claim 2, the moving stage on which the substrate is placed moves in a direction orthogonal to the width direction of the substrate. For this reason, it is not necessary to provide a scanning optical system for scanning the line beam, and the apparatus configuration is simplified.
[0017]
According to a third aspect of the present invention, there is provided a laser thin film forming apparatus in which a laser beam is incident into a reaction vessel, the solid material stored in the reaction vessel is irradiated to vaporize the solid material, and a thin film is deposited on the substrate. A laser light source in which laser emitting portions from which the laser beam is emitted are arranged in a line along the width direction of the solid material, and a laser beam emitted from the laser light source is lined across the width direction of the solid material And an optical system for condensing the light into a shape.
[0018]
In a third aspect of the invention, a laser beam is incident into the reaction vessel and the solid material stored in the reaction vessel is irradiated to vaporize the solid material, thereby depositing a thin film on the substrate.
[0019]
Here, the laser emitting portions of the laser light source are arranged in a line along the width direction of the solid material. This laser beam is condensed in a line shape over the width of the solid material by the optical system, and is irradiated as a line beam over the width direction of the solid material.
[0020]
For this reason, it is not necessary to scan the solid material or the laser beam in the width direction of the solid material and irradiate the entire surface of the solid material with the laser beam as in the prior art.
[0021]
According to a fourth aspect of the present invention, the laser light source is configured by any one of the following (1) to (5).
(1) Condensing optics for condensing a plurality of semiconductor lasers, one optical fiber, and a laser beam emitted from each of the plurality of semiconductor lasers, and coupling the condensed beam to an incident end of the optical fiber And a combined laser light source.
(2) A combined laser light source in which the semiconductor laser in the combined laser light source of (1) is constituted by a multi-cavity laser having a plurality of light emitting points.
(3) A multi-cavity laser having a plurality of light emitting points, a single optical fiber, and a laser beam emitted from each of the plurality of light emitting points are condensed, and the condensed beam is input to the incident end of the optical fiber. And a condensing optical system coupled to the optical system.
(4) A fiber array light source comprising a plurality of the combined laser light sources, each of the light emitting points at the emission end of the optical fiber of the plurality of combined laser light sources arranged in an array, or a fiber bundle arranged in a bundle light source.
(5) Condensing optics for condensing a single semiconductor laser, one optical fiber, and a laser beam emitted from the single semiconductor laser, and coupling the condensed beam to the incident end of the optical fiber And a fiber bundle light source in which each of the light emitting points at the emission ends of the optical fibers of the plurality of fiber light sources is arranged in an array, or a fiber bundle light source arranged in a bundle.
[0022]
In the invention according to claim 4, the above-mentioned light source is suitably used as the laser light source. Of these, a combined laser light source and a fiber array light source and a fiber bundle light source using a plurality of combined laser light sources, which can easily achieve high output and high brightness, are particularly preferable. That is, the combined laser light source can increase the brightness by increasing the number of laser beams to be combined. Thereby, the crystal characteristics of the polysilicon film can be improved and the resistance can be lowered, and the carrier mobility can be further increased. Further, in the fiber array light source and the fiber bundle light source, since the light source is configured by bundling a plurality of optical fibers, the area that can be irradiated with laser simultaneously increases, and a large area can be formed into a thin film at high speed. That is, further speeding up is easy.
[0023]
The invention according to claim 5 is characterized in that the laser light source is composed of a group III nitrogen-based semiconductor laser having a light emitting layer containing at least one of Al, Ga, and In.
[0024]
In the invention described in claim 5, a group III nitrogen-based semiconductor laser having a light emitting layer containing at least one of Al, Ga, and In is used as a laser light source, which is lower in cost and longer than an ArF excimer laser. A lifetime light source can be constructed.
[0025]
For example, by using a GaN-based semiconductor laser that can be continuously driven and has excellent output stability as a laser light source, the pulse width and repetition frequency can be varied, so that the particle size of the thin film can be controlled.
[0026]
Further, it is smaller and more reliable than a thin film forming apparatus using an ArF excimer laser, is easy to maintain, and has high energy efficiency. Furthermore, since a laser beam having a wavelength of 200 to 450 nm is used, it is not necessary to use an optical system of a special material, and the cost is reduced. In addition, since the repetition frequency is as high as 10 MHz to 1 GHz, the time for storing energy is short, and the deposition rate is high.
[0027]
In addition, as a laser light source provided with the several laser emission part, the following light sources are used suitably. Of these, a combined laser light source and a fiber array light source and a fiber bundle light source using a plurality of combined laser light sources, which can easily achieve high output and high brightness, are particularly preferable. In other words, the combined laser light source can increase the brightness by increasing the number of laser beams to be combined, and the film forming speed is increased.
[0028]
In the case of a laser light source that uses the output end of the optical fiber as a laser output part, it is preferable to use an optical fiber having a uniform core diameter and a smaller cladding diameter at the output end than the cladding diameter at the incident end.
[0029]
In a fiber light source using an optical fiber having a large cladding diameter at the output end, when bundled, the diameter of the light emitting point of the laser output section becomes large, and a sufficient depth of focus cannot be obtained. However, since the core approaches by reducing the cladding diameter at the emission end, the luminance of the light source can be increased. This increases the depth of focus and increases the area where film formation can be performed with a single irradiation.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a laser thin film forming apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
(Laser thin film forming equipment)
As shown in FIG. 1, the laser thin film forming apparatus 70 includes a box-shaped chamber 72 that is a closed space. On the side wall of the chamber 72, there are provided an incident window 74 into which a line beam emitted from a fiber array light source 66, which will be described later, is incident, and an exit window 76 that is an exit of the line beam. The incident window 74 is sealed with a synthetic quartz glass 78 having a high transmittance.
[0031]
The chamber 72 is provided with a supply path 80 for supplying silane gas (SiH ₄ ) as a source gas, and a source gas cylinder 82 is connected via a mass flow controller 84. An exhaust passage 86 for exhausting exhaust gas is disposed on the bottom wall of the chamber 72, and the gas in the chamber 72 is exhausted by the vacuum pump 88 and the internal pressure of the chamber 72 is adjusted.
[0032]
An inlet pipe 92 that guides the gas in the chamber 72 to the quadrupole mass filter 90 is connected to the bottom wall of the chamber 72, and the reaction product in the chamber 72 can be monitored by the quadrupole mass filter 90. It is possible.
[0033]
On the other hand, a moving stage 96 on which a glass substrate 94 on which a thin film is to be formed is placed is disposed at the center of the chamber 72. A heater 100 is built in the moving stage 96 and holds the substrate 94 in a temperature range of about 250 ° C.
[0034]
The moving stage 96 is arranged at a position where the thin film S can be deposited by exciting the source gas with a line beam. That is, it is located within the line beam irradiation region.
[0035]
In addition, a recess 102 that engages with the guide rail 98 is formed on the lower surface of the moving stage 96, and the moving stage 96 moves in the direction of arrow A along the guide rail 98 at a predetermined speed. This moving direction (arrow A direction) is a direction orthogonal to the beam waist W of the line beam (photolysis reaction region: see FIG. 4).
(Fiber array light source)
As shown in FIG. 5A, the fiber array light source 66 includes a number of laser modules 64, and one end of the multimode optical fiber 30 is coupled to each laser module 64. An optical fiber 31 having the same core diameter as that of the multimode optical fiber 30 and a smaller cladding diameter than the multimode optical fiber 30 is coupled to the other end of the multimode optical fiber 30.
[0036]
The emission ends (light emission points) of the optical fiber 31 are arranged in a line in a line to form a laser emission unit 68. The arrangement direction of the light emitting points is a direction orthogonal to the moving direction (arrow A direction) of the moving stage 96 provided in the chamber 72 and is predetermined in the width direction of the substrate 94 placed on the moving stage 96. A line beam having a width of is traversed.
[0037]
As shown in FIG. 5B, the emission end of the optical fiber 31 is sandwiched and fixed between two support plates 65 having a flat surface. The output end of the optical fiber 31 is protected by a transparent protective plate 63 such as glass. The protection plate 63 may be disposed in close contact with the end surface of the optical fiber 31 or may be disposed so that the end surface of the optical fiber 31 is sealed. The exit end portion of the optical fiber 31 has a high light density and is likely to collect dust and easily deteriorate. However, the protective plate 63 can prevent the dust from adhering to the end face and can also delay the deterioration.
[0038]
Further, a collimator lens 128 is provided on the front surface of the laser emitting unit 68, and the laser beam emitted from the laser emitting unit 68 is collimated. The collimated laser beam is focused only by the cylindrical lens 104 in a direction orthogonal to the arrangement direction of the emission end portions of the optical fiber 31.
[0039]
The cylindrical lens 104 has a curvature in a predetermined direction and is long in a direction orthogonal to the predetermined direction, and a longitudinal direction (a direction orthogonal to the predetermined direction) is parallel to the arrangement direction of the emission ends of the optical fiber 30. It is arranged to be. As a result, an image is formed in a line shape above the substrate 94 to form a line beam.
[0040]
Further, in this embodiment, in order to arrange the emission ends of the optical fibers 31 having a small cladding diameter in a line without any gap, the multimode light is interposed between two multimode optical fibers 30 adjacent to each other at a large cladding diameter. The fibers 30 are stacked, and the output end of the optical fiber 31 coupled to the stacked multimode optical fiber 30 is connected to the two multimode optical fibers 30 adjacent to each other at a portion having a large cladding diameter. They are arranged so as to be sandwiched between the two exit ends.
[0041]
For example, as shown in FIG. 6, an optical fiber 31 having a length of 1 to 30 cm and having a small cladding diameter is coaxially connected to the tip of the multimode optical fiber 30 having a large cladding diameter on the laser beam emission side. Can be obtained by linking them together. In the two optical fibers, the incident end face of the optical fiber 31 is fused and joined to the outgoing end face of the multimode optical fiber 30 so that the central axes of both optical fibers coincide. As described above, the diameter of the core 31 a of the optical fiber 31 is the same as the diameter of the core 30 a of the multimode optical fiber 30.
[0042]
In addition, a short optical fiber in which an optical fiber having a short cladding diameter and a large cladding diameter is fused to an optical fiber having a short cladding diameter and a large cladding diameter may be coupled to the output end of the multimode optical fiber 30 via a ferrule or an optical connector. Good. By detachably coupling using a connector or the like, the tip portion can be easily replaced when an optical fiber having a small cladding diameter is broken, and the cost required for the irradiation head maintenance can be reduced. Hereinafter, the optical fiber 31 may be referred to as an emission end portion of the multimode optical fiber 30.
[0043]
The multimode optical fiber 30 and the optical fiber 31 may be any of a step index type optical fiber, a graded index type optical fiber, and a composite type optical fiber. For example, a step index type optical fiber manufactured by Mitsubishi Cable Industries, Ltd. can be used. In the present embodiment, the multimode optical fiber 30 and the optical fiber 31 are step index type optical fibers, and the multimode optical fiber 30 has a cladding diameter = 125 μm, a core diameter = 25 μm, NA = 0.2, an incident end face. The transmittance of the coat is 99.5% or more, and the optical fiber 31 has a cladding diameter = 60 μm, a core diameter = 25 μm, and NA = 0.2.
[0044]
Generally, in a laser beam in the infrared region, propagation loss increases as the cladding diameter of the optical fiber is reduced. For this reason, a suitable cladding diameter is determined according to the wavelength band of the laser beam. However, the shorter the wavelength, the smaller the propagation loss. With a laser beam with a wavelength of 405 nm emitted from a GaN-based semiconductor laser, the cladding thickness {(cladding diameter−core diameter) / 2} is set to an infrared light with a wavelength band of 800 nm. The propagation loss hardly increases even if it is about ½ of the case of propagating infrared light and about ¼ of the case of propagating infrared light in the 1.5 μm wavelength band for communication. Therefore, the cladding diameter can be reduced to 60 μm.
[0045]
However, the cladding diameter of the optical fiber 31 is not limited to 60 μm. The clad diameter of an optical fiber used in a conventional fiber light source is 125 μm, but the depth of focus becomes deeper as the clad diameter becomes smaller. Therefore, the clad diameter of a multimode optical fiber is preferably 80 μm or less, more preferably 60 μm or less. Preferably, it is 40 μm or less. On the other hand, since the core diameter needs to be at least 3 to 4 μm, the cladding diameter of the optical fiber 31 is preferably 10 μm or more.
[0046]
The laser module 64 is configured by a combined laser light source (fiber light source) shown in FIG. This combined laser light source includes a plurality of (for example, seven) chip-like lateral multimode or single mode GaN-based semiconductor lasers LD1, LD2, LD3, LD4, LD5, LD6, arrayed and fixed on the heat block 10. And LD7, collimator lenses 11, 12, 13, 14, 15, 16, and 17 provided corresponding to each of the GaN-based semiconductor lasers LD1 to LD7, one condenser lens 20, and one multi-lens. Mode optical fiber 30. The number of semiconductor lasers is not limited to seven. For example, as many as 20 semiconductor laser beams can be incident on a multimode optical fiber having a cladding diameter = 60 μm, a core diameter = 50 μm, and NA = 0.2. In addition, the number of optical fibers can be further reduced.
[0047]
The GaN-based semiconductor lasers LD1 to LD7 all have the same oscillation wavelength (for example, 405 nm), and the maximum output is also all the same (for example, 100 mW for the multimode laser and 30 mW for the single mode laser). As the GaN-based semiconductor lasers LD1 to LD7, lasers having an oscillation wavelength other than the above 405 nm in a wavelength range of 350 nm to 450 nm may be used.
[0048]
As shown in FIGS. 8 and 9, the above combined laser light source is housed in a box-shaped package 40 having an upper opening together with other optical elements. The package 40 includes a package lid 41 created so as to close the opening thereof. After the deaeration process, a sealing gas is introduced, and the package 40 and the package lid 41 are closed by closing the opening of the package 40 with the package lid 41. The combined laser light source is hermetically sealed in a closed space (sealed space) formed by 41.
[0049]
A base plate 42 is fixed to the bottom surface of the package 40, and the heat block 10, a condensing lens holder 45 that holds the condensing lens 20, and the multimode optical fiber 30 are disposed on the top surface of the base plate 42. A fiber holder 46 that holds the incident end is attached. The exit end of the multimode optical fiber 30 is drawn out of the package from an opening formed in the wall surface of the package 40.
[0050]
Further, a collimator lens holder 44 is attached to the side surface of the heat block 10, and the collimator lenses 11 to 17 are held. An opening is formed in the lateral wall surface of the package 40, and wiring 47 for supplying a driving current to the GaN-based semiconductor lasers LD1 to LD7 is drawn out of the package through the opening.
[0051]
In FIG. 9, in order to avoid complication of the figure, only the GaN semiconductor laser LD7 is numbered among the plurality of GaN semiconductor lasers, and only the collimator lens 17 is numbered among the plurality of collimator lenses. doing.
[0052]
FIG. 10 shows the front shape of the attachment part of the collimator lenses 11-17. Each of the collimator lenses 11 to 17 is formed in a shape obtained by cutting a region including the optical axis of a circular lens having an aspherical surface into a long and narrow plane. This elongated collimator lens can be formed, for example, by molding resin or optical glass. The collimator lenses 11 to 17 are closely arranged in the arrangement direction of the light emitting points so that the length direction is orthogonal to the arrangement direction of the light emitting points of the GaN-based semiconductor lasers LD1 to LD7 (left and right direction in FIG. 10).
[0053]
On the other hand, each of the GaN-based semiconductor lasers LD1 to LD7 includes an active layer having a light emission width of 2 μm, and each of the laser beams B1 in a state parallel to the active layer and a divergence angle in a direction perpendicular to the active layer, respectively, for example A laser emitting ~ B7 is used. These GaN-based semiconductor lasers LD1 to LD7 are arranged so that the light emitting points are arranged in a line in a direction parallel to the active layer.
[0054]
Accordingly, in the laser beams B1 to B7 emitted from the respective light emitting points, the direction in which the divergence angle is large coincides with the length direction and the divergence angle is small with respect to the elongated collimator lenses 11 to 17 as described above. Incident light is incident in a state where the direction coincides with the width direction (direction perpendicular to the length direction). That is, the collimator lenses 11 to 17 have a width of 1.1 mm and a length of 4.6 mm, and the horizontal and vertical beam diameters of the laser beams B1 to B7 incident thereon are 0.9 mm and 2. 6 mm. Each of the collimator lenses 11 to 17 has a focal length f ₁ = 3 mm, NA = 0.6, and a lens arrangement pitch = 1.25 mm.
[0055]
The condensing lens 20 is formed by cutting a region including the optical axis of a circular lens having an aspheric surface into a long and narrow shape in parallel planes, and is long in the arrangement direction of the collimator lenses 11 to 17, that is, in a horizontal direction and short in a direction perpendicular thereto. Is formed. This condenser lens 20 has a focal length f ₂ = 23 mm and NA = 0.2. This condensing lens 20 is also formed by molding resin or optical glass, for example.
[0056]
The operation of the laser thin film forming apparatus will be described.
[0057]
Each of the laser beams B1, B2, B3, B4, B5, B6, and B7 emitted in a divergent light state from each of the GaN-based semiconductor lasers LD1 to LD7 constituting the combined laser light source of the fiber array light source 66 corresponds. The collimator lenses 11 to 17 collimate the light. The collimated laser beams B <b> 1 to B <b> 7 are collected by the condenser lens 20 and converge on the incident end face of the core 30 a of the multimode optical fiber 30.
[0058]
In this example, the collimator lenses 11 to 17 and the condenser lens 20 constitute a condensing optical system, and the condensing optical system and the multimode optical fiber 30 constitute a multiplexing optical system. That is, the laser beams B1 to B7 condensed as described above by the condenser lens 20 enter the core 30a of the multimode optical fiber 30 and propagate through the optical fiber to be combined with one laser beam B. The light is emitted from the optical fiber 31 coupled to the output end of the multimode optical fiber 30.
[0059]
In each laser module, when the coupling efficiency of the laser beams B1 to B7 to the multimode optical fiber 30 is 0.85 and each output of the GaN-based semiconductor lasers LD1 to LD7 is 30 mW (when a single mode laser is used). Can obtain a combined laser beam B with an output of 180 mW (= 30 mW × 0.85 × 7) for each of the optical fibers 31 arranged in an array. Therefore, the output from the laser emitting section 68 in which 1200 optical fibers 31 are arranged in an array is about 216 W (= 180 mW × 1200).
[0060]
In this embodiment, the number of the optical fibers 31 is 1200, but the number of the optical fibers 31 is determined so that the length of the line beam is larger than the width size of the substrate 94 on which the thin film S is deposited. .
[0061]
That is, by increasing the number of optical fibers to be arrayed, the line beam length can be extended while maintaining the energy intensity and the uniformity thereof. Therefore, it can be used as a thin film forming apparatus for large TFT-LCD panels.
[0062]
In the laser emitting section 68 of the fiber array light source 66, high-luminance light emitting points are arranged in a line along the main scanning direction. A conventional fiber light source that couples a laser beam from a single semiconductor laser to a single optical fiber has a low output, so a desired output could not be obtained unless multiple rows are arranged. Since the combined laser light source used in the form has a high output, a desired output can be obtained even with a small number of columns, for example, one column.
[0063]
Further, when the multimode optical fiber 30 is a step index type optical fiber having a cladding diameter = 125 μm, a core diameter = 50 μm, and NA = 0.2, the beam diameter at the laser emitting portion 68 is 50 μm × 150 mm. is there. The irradiation area above the substrate 94 is 50 μm × 150 mm. Therefore, when irradiation is performed at 1 msec, the light density on the substrate 94 is 960 mJ / cm ² . Even if the loss due to the optical system is estimated to be about 75%, the light density on the irradiated surface is 720 mJ / cm ² . Therefore, a line length of 150 mm can be irradiated in 1 second.
[0064]
With such a configuration, the laser beam emitted in a line shape is converted into parallel light by the collimator lens 128 and is condensed by the cylindrical lens 104 only in a direction orthogonal to the arrangement direction of the optical fibers 31 to become a line beam. . The line beam is incident from the entrance window 74 of the chamber 72 and, as shown in FIG. 2 to FIG. 4, the range of 50 μm to 60 μm (beam waist × 1.2) as a reaction region is centered on the beam waist (50 μm). Light energy is applied across the width direction of the substrate 94. Moreover, since the depth of focus is large, the width of the reaction region is also large.
[0065]
On the other hand, the substrate 94 is held in a temperature range of about 300 ° C. by the heater 100. Further, silane gas (SiH ₄ ) diluted with 10% He is supplied as a source gas from the supply path 80. Silane gas diffuses above the substrate 94 and is decomposed by the light energy of the laser beam, and an insulating thin film S of SiO ₂ is deposited on the glass substrate 94 across the width of the reaction region.
[0066]
Here, since the region irradiated with the line beam extends in the width direction of the substrate, it is not necessary to deflect and scan the laser beam as in the conventional laser beam of a single light source (see FIG. 13).
[0067]
Further, in order to form a film on the entire surface of the substrate 94, the moving stage 96 moves at a constant speed in the direction of arrow A, and an insulating thin film of SiO ₂ is formed in a large range sequentially from the end of the substrate 94.
[0068]
In this embodiment, the substrate 94 is moved to form a film on the entire surface, but the line beam can be deflected only in the A direction so that the entire surface is irradiated with the line beam.
[0069]
Further, the source gas supplied to the chamber 72 naturally varies depending on the type of the target film. When forming a metal film, the metal carbonyl Cr (CO) ₆ , Mo (CO) ₆ , W (CO ) ₆ etc. as raw material gases, respectively, Cr, Mo, W metal films are formed, Al (CH ₃ ) ₃ is used as a raw material Al wiring, or by utilizing low temperature and low damage, various It can be used for film formation.
[0070]
Furthermore, the film thickness can be adjusted by controlling the light amount of the laser beam, and the spatial distribution of light energy can also be controlled by scanning the laser beam.
[0071]
Next, a laser / sputtered thin film forming apparatus according to a second embodiment will be described.
[0072]
As shown in FIG. 11, a target support base 110 on which a Si target 108 is placed as a solid material is provided at the bottom of the vacuum chamber 106. A holder 112 that holds the substrate 94 is suspended from the ceiling of the vacuum chamber 106, and the temperature of the substrate 94 is kept at 250 ° C. by the infrared lamp 114.
[0073]
An introduction pipe 116 for introducing an inert gas such as Ar (argon) is provided on the right side wall of the vacuum chamber 106, and an exhaust pipe 118 for exhausting the exhaust gas in the vacuum chamber 106 is disposed below the introduction pipe 116. Has been. An incident window 120 is provided on the left side wall of the vacuum chamber 106 so that the line beam enters the vacuum chamber 106.
[0074]
Further, the line beam is folded back by the reflection mirror 130, condensed by the lens 132, passes through the incident window 120, irradiates the Si target 108, generates plume P (sputtered particles), and has a good quality on the surface of the substrate 94. The Si film is formed at a high speed.
[0075]
Here, as shown in FIG. 12, since the Si target 108 is irradiated with the line beam over the entire width, the entire surface of the rectangular Si target 108 is obtained by moving the target support 110 in the direction of the arrow. The line beam is irradiated without any leakage. For this reason, a plume can be generated efficiently.
[0076]
As described above, according to the present invention, a uniform thin film can be formed on a rectangular substrate facing the rectangular target by uniformly irradiating the rectangular target with a line beam. In addition, since optical deflection is unnecessary, the optical system is simplified, and a thin film forming apparatus can be realized at low cost.
[0077]
In this embodiment, a GaN-based semiconductor laser has been described as an example of the semiconductor laser. However, a group III nitrogen-based semiconductor laser including at least one of Al, Ga, and In, that is, Al _X Ga _Y In _Z As described above, the optical gap of the light emitting layer can be changed by arbitrarily changing the mixing ratio of XYZ.
[0078]
For example, when an optical gap of GaN of 3.2 to 3.5 eV is used as a reference, by adding Al to this, it can be increased by about 6.5 eV, and can correspond to the ultraviolet region. Moreover, by adding In, it can be changed to about 1.9 eV, and can correspond to a visible region. The wavelength of the laser is about 200 nm in the case of Al nitrogen and about 350 nm in the case of Ga nitrogen.
[0079]
【The invention's effect】
Since the present invention has the above-described structure, a large area can be uniformly formed, and a low-cost and long-life laser light source can be obtained.
[Brief description of the drawings]
FIG. 1 is an overall view of a laser thin film forming apparatus according to a first embodiment.
FIG. 2 is a perspective view showing a positional relationship between a line beam and a substrate in the laser thin film forming apparatus according to the first embodiment.
FIG. 3 is a plan view showing a positional relationship between a line beam and a substrate in the laser thin film forming apparatus according to the first embodiment.
FIG. 4 is a side view showing a positional relationship between a line beam and a substrate in the laser thin film forming apparatus according to the first embodiment.
5A is a perspective view showing a configuration of a fiber array light source, and FIG. 5B is a partially enlarged view of A. FIG.
FIG. 6 is a diagram showing a configuration of a multimode optical fiber.
FIG. 7 is a plan view showing a configuration of a combined laser light source.
FIG. 8 is a plan view showing a configuration of a laser module.
9 is a side view showing the configuration of the laser module shown in FIG. 8. FIG.
10 is a partial side view showing the configuration of the laser module shown in FIG. 8. FIG.
FIG. 11 is an overall view of a laser thin film forming apparatus according to a second embodiment.
FIG. 12 is a perspective view showing a positional relationship between a line beam and a target.
FIG. 13 is an explanatory view of a conventional laser thin film forming apparatus.
[Explanation of symbols]
64 Laser module 66 Fiber array light source (laser light source)
68 Laser emitting unit 72 Chamber (reaction vessel)
96 Moving stage 104 Cylindrical lens (optical system)
106 Vacuum chamber (reaction vessel)
108 Si target (solid material)
110 Target support

Claims (5)

In a laser thin film forming apparatus in which a laser beam is incident into a reaction vessel, a source gas supplied into the reaction vessel is photodecomposed, and a thin film is deposited on a substrate.
A laser light source configured to generate a plurality of light emitting points by at least one semiconductor laser;
An optical system for condensing the laser beam emitted from the laser light source in a line shape in the width direction of the substrate;
An apparatus for forming a laser thin film, comprising: 2. The laser thin film forming apparatus according to claim 1, further comprising a moving stage on which the substrate is mounted and movable in a direction perpendicular to the width direction of the substrate. In a laser thin film forming apparatus in which a laser beam is incident into a reaction vessel and the solid material stored in the reaction vessel is irradiated to vaporize the solid material and deposit a thin film on the substrate.
A laser light source in which laser emitting portions from which the laser beam is emitted are arranged in a line along the width direction of the solid material;
An optical system for condensing the laser beam emitted from the laser light source in a line shape across the width direction of the solid material;
An apparatus for forming a laser thin film, comprising: The laser thin film forming apparatus according to any one of claims 1 to 3, wherein the laser light source is configured by any one of the following light sources (1) to (5).
(1) Condensing optics for condensing a plurality of semiconductor lasers, one optical fiber, and a laser beam emitted from each of the plurality of semiconductor lasers, and coupling the condensed beam to an incident end of the optical fiber And a combined laser light source.
(2) A combined laser light source in which the semiconductor laser in the combined laser light source of (1) is constituted by a multi-cavity laser having a plurality of light emitting points.
(3) A multi-cavity laser having a plurality of light emitting points, a single optical fiber, and a laser beam emitted from each of the plurality of light emitting points are condensed, and the condensed beam is input to the incident end of the optical fiber. And a condensing optical system coupled to the optical system.
(4) A fiber array light source comprising a plurality of the combined laser light sources, each of the light emitting points at the emission end of the optical fiber of the plurality of combined laser light sources arranged in an array, or a fiber bundle arranged in a bundle light source.
(5) Condensing optics for condensing a single semiconductor laser, one optical fiber, and a laser beam emitted from the single semiconductor laser, and coupling the condensed beam to the incident end of the optical fiber And a fiber bundle light source in which each of the light emitting points at the emission ends of the optical fibers of the plurality of fiber light sources is arranged in an array, or a fiber bundle light source arranged in a bundle. The laser according to any one of claims 1 to 4, wherein the laser light source is composed of a group III nitrogen semiconductor laser having a light emitting layer containing at least one of Al, Ga, and In. Thin film forming equipment.

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