JP2010103177A - Laser irradiation apparatus and laser irradiation method - Google Patents

Abstract

An object of the present invention is to prevent the occurrence of linear crystal spots and luminance spots.
SOLUTION: A plurality of drivers 43A to 43F that emit laser beams having arbitrary laser output values from a plurality of semiconductor laser elements 30A to 30F, and a plurality of laser beams emitted from a plurality of laser light sources are guided through a light guide plate 34. A linear laser spot 45 is formed by emitting through the laser beam, and the irradiation target is irradiated with the laser spot 45, the moving stage carrying the irradiation target is moved at a predetermined speed, and Displacement of the laser output value in the longitudinal direction of the linear laser spot by changing the laser output value for each of the semiconductor laser elements 30A to 30F with the lapse of time while maintaining the sum per unit time by the plurality of drivers 43A to 43F. Irradiates an irradiation object with a linear laser spot while temporally changing the laser profile representing.
[Selection] Figure 1

Description

  The present invention relates to a laser irradiation apparatus and a laser irradiation method for irradiating an irradiation object with a linear laser spot, and in particular, a laser irradiation apparatus and a laser irradiation capable of preventing the occurrence of linear luminance spots on a flat display. Regarding the method.

  Generally, a laser irradiation apparatus is used in a laser annealing apparatus or the like that generates polysilicon by modifying a physical property of a silicon film by irradiating a laser spot focused on an irradiation object such as a silicon film. Yes.

  A laser irradiation apparatus for irradiating a laser spot according to the prior art includes a plurality of semiconductor laser elements that emit laser light, a plurality of optical fibers that enter one end of laser light emitted from each of the plurality of semiconductor laser elements, A light guide plate that emits a plurality of laser beams emitted from the other end of the optical fiber from one end side surface and diffusely reflects inside and emits from the other end side surface, and a collimator that converts the laser beam emitted from the light guide plate into parallel light A lens, an objective lens that irradiates the irradiation target with a linear laser spot that is a collimated laser beam emitted from the collimating lens, and a direction orthogonal to the longitudinal direction of the linear laser spot. A moving stage that moves the object to the irradiation object by irradiating the irradiation object with the linear laser spot. It is configured so as to modify the sex.

The following Patent Document 1 is cited as a document describing a technique related to a laser irradiation apparatus using a plurality of semiconductor laser elements as a light source.
JP 2007-88050 A

  In the laser irradiation apparatus according to the above-described prior art, a plurality of semiconductor laser elements having variation in characteristics are used as a light source, and a plurality of laser beams are condensed on one linear laser spot by a light guide plate. There is a problem that it is difficult to equalize the laser output value in the longitudinal direction with high accuracy, and this problem will be described with reference to FIG.

  FIG. 14 is a diagram for explaining the distribution of the laser output value in the longitudinal direction of the linear laser spot and the state of the irradiation object modified by the linear laser spot. As is apparent from FIG. 14, a linear laser spot obtained by converging a plurality of laser beams into one by a light guide plate has a characteristic that becomes a laser profile 12 in which unevenness (variation) occurs in the output value in the longitudinal direction of the laser spot. When the laser spot 13 having the laser profile 12 is scanned on the silicon film (reference numeral 14), the modification indicated by the oblique lines in the figure is sufficiently performed along the unevenness of the output value on the silicon film plane. There is a problem that the pixel transistor 15 that has been performed and the pixel transistor 16 that is relatively insufficiently modified as shown in white are generated, and a linear crystal spot is generated.

  As shown in FIG. 7, in the laser neil in which a large number of displays 61 are manufactured on one glass substrate 60, the laser spot 13 having the laser profile 12 is, for example, in the direction of the arrow 64 and the arrow. When the modification is performed by moving to 68, a linear crystal spot 65 is generated. In the pixel transistor in which the linear crystal spot 65 is generated and the pixel transistor in which the crystal spot is not generated, the electric mobility, Device characteristics such as switching threshold and current ON / OFF ratio are different.

  Further, as shown in FIG. 7, the linear crystal spots are linearly arranged when the laser spot 13 is reciprocated in the direction of the arrow 64 and the arrow 68, and the laser spot 13 is scanned in duplicate during the reciprocal movement. There is a problem in that the characteristics of the pixel transistor are different and a linear crystal spot 69 is generated by this overlapping scanning.

  For this reason, in the display 61 in which the above-described crystal spots 65 and 69 are generated, since the pixel transistors having different characteristics are arranged in a line when the display is driven, as shown in FIG. There was a problem that 81) was generated.

  In particular, the luminance spots in the display 61 sold to general customers are very conspicuous because they appear to be continuously connected as lines, and there is also a problem that the problem of poor appearance to the customers is caused.

  The objective of this invention is providing the laser irradiation apparatus and laser irradiation method which prevent that a linear crystal spot and a brightness spot arise in an irradiation target object.

  In order to achieve the above object, the present invention provides a laser irradiation apparatus for modifying an irradiation object by irradiating the irradiation object with a linear laser spot and scanning in the short axis direction of the linear laser spot. The first feature is that the beam profile in the major axis direction of the linear laser spot is temporally changed while scanning on the object.

Furthermore, the present invention is a laser irradiation apparatus that forms a linear laser spot by emitting a plurality of laser beams emitted from a plurality of laser light sources through a light guide plate, and irradiates the irradiation target with the laser spot. There,
A plurality of laser light sources that emit laser light;
A plurality of driver circuits for driving the laser light sources to emit laser light emitted from the plurality of laser light sources at an arbitrary output value;
A moving stage for moving the irradiation object in a direction perpendicular to the longitudinal direction of the linear laser spot;
A controller that moves the moving stage at an arbitrary moving speed and independently controls laser output values emitted from a plurality of laser light sources through the plurality of driver circuits;
A second feature is that the control unit independently changes a laser output value emitted from each of the plurality of laser light sources by the plurality of driver circuits with time while moving the moving stage at a predetermined speed. To do.

  According to the present invention, in the laser irradiation apparatus according to the second feature, the control unit includes a plurality of laser output values emitted from a plurality of laser light sources through the plurality of driver circuits so as to maintain a total sum at an arbitrary time. The third feature is that each driver circuit is independently controlled.

  According to the present invention, in the laser irradiation apparatus having the second or third feature, the control unit outputs a laser power in a range of 2% to 50% of the base power Pb to a base power Pb that is a predetermined laser output value. A fourth feature is that laser output values emitted from a plurality of laser light sources are independently changed over time by superimposing a superposition power Pa as a value.

  According to the present invention, in the laser irradiation apparatus of the fourth feature, when the pulse width of the laser output is Pw, the control unit contributes to the laser output values at both ends of the linear laser spot. The pulse modulation width is set in the range of 50% ≦ (Pw / (Pb + Pa) × 100%) ≦ 98%, and the pulse modulation width of the other laser light sources excluding the laser light sources contributing to the laser output values at both ends is set. , 60% ≦ (Pw / (Pb + Pa) × 100%) ≦ 98%, the pulse modulation width of the laser light source at both ends is controlled to be larger than the pulse modulation width at the center. This is the fifth feature.

  According to the present invention, in the laser irradiation apparatus according to any one of the second to fifth features, the irradiation object is a flat display including a plurality of pixel transistors, and the interval between the pixel transistors of the flat display is L, a laser spot. When the scanning speed is V and the laser light emission pulse frequency is f, the control unit performs laser light emission by setting the laser light emission pulse frequency f in a range of V / (5L) <f <V / L. Is a sixth feature.

  In the laser irradiation apparatus of any one of the second to fifth features, the present invention is a flat display in which the irradiation object includes a plurality of pixel transistors, and the short axis length of the linear laser spot is d, When the pixel transistor interval is L, the laser spot scanning speed is V, and the laser emission pulse frequency is f, the control unit sets the laser emission pulse frequency f in the range of V / L <f <V / d. The seventh feature is that the laser emission is performed.

  In the laser irradiation apparatus of any one of the second to fifth features, the present invention is a flat display in which the irradiation object includes a plurality of pixel transistors, and the short axis length of the linear laser spot is d, The eighth feature is that laser emission is performed by setting V / d <f in the range where V is the scanning speed of the laser spot and f is the laser emission pulse frequency.

  According to a ninth aspect of the present invention, in the laser irradiation apparatus according to any one of the first to eighth features, the laser light source is a semiconductor laser element that emits laser light having a laser wavelength of 370 nm to 480 nm. .

  According to a tenth feature of the present invention, in the laser irradiation apparatus of any one of the first to eighth features, the laser light source is a semiconductor laser element that emits laser light having a laser wavelength of 600 nm to 850 nm.

  In addition, according to the present invention, in the laser irradiation apparatus having any one of the first to eighth features, an eleventh feature is that the laser light source is a solid-state laser that emits laser light having a laser wavelength of 350 nm to 550 nm.

  Furthermore, the present invention relates to a laser irradiation method for modifying an irradiation object by irradiating the irradiation object with a linear laser spot and scanning in the short axis direction of the linear laser spot. However, the twelfth feature is that the beam profile in the major axis direction of the linear laser spot is changed temporally.

The present invention also provides a plurality of laser light sources that emit laser light, a plurality of driver circuits that drive the laser light sources to emit laser light emitted from the plurality of laser light sources at an arbitrary output value, and an irradiation target A moving stage for moving an object in a direction orthogonal to the longitudinal direction of the linear laser spot, and a laser output value for moving the moving stage at an arbitrary moving speed and emitting from a plurality of laser light sources through the plurality of driver circuits A control unit that independently controls the laser beam, and a plurality of laser beams emitted from a plurality of laser light sources are emitted through a light guide plate to form a linear laser spot, and the irradiation target is irradiated with the laser spot. A laser irradiation method of a laser irradiation apparatus for performing
The thirteenth aspect is that the control unit independently changes each laser output value emitted from each of the plurality of laser light sources by the plurality of driver circuits over time while moving the moving stage at a predetermined speed. Features.

  In the laser irradiation method according to the thirteenth feature, the present invention provides a plurality of control units so that the total sum of laser output values emitted from a plurality of laser light sources through the plurality of driver circuits at an arbitrary time is maintained at a predetermined value. The fourteenth feature is that each driver circuit is independently controlled.

  According to the present invention, in the laser irradiation method according to the thirteenth or fourteenth feature, the control unit has a laser in a range of 2% to 50% of the base power Pb to a base power Pb that is a predetermined laser output value. A fifteenth feature is that laser output values emitted from a plurality of laser light sources are independently changed over time by superimposing superposition power Pa that is an output value.

  In the laser irradiation method of the fifteenth aspect, the present invention provides a laser light source that contributes to laser output values at both ends of the linear laser spot when the pulse width of laser output is Pw. The pulse modulation width is set in the range of 50% ≦ (Pw / (Pb + Pa) × 100%) ≦ 98%, and the pulse modulation width of the other laser light sources excluding the laser light sources contributing to the laser output values at both ends is set. , 60% ≦ (Pw / (Pb + Pa) × 100%) ≦ 98%, the pulse modulation width of the laser light source at both ends is controlled to be larger than the pulse modulation width at the center. This is the sixteenth feature.

  According to the present invention, in the laser irradiation method according to any one of the thirteenth to sixteenth aspects, the irradiation object is a flat display including a plurality of pixel transistors, and the interval between the pixel transistors of the flat display is L, When the scanning speed is V and the laser emission pulse frequency is f, the control unit performs laser emission by setting the laser emission pulse frequency f to a range of V / (5L) <f <V / L. The seventeenth feature.

  In the laser irradiation method according to any one of the thirteenth to sixteenth aspects, the present invention is the flat display in which the irradiation object includes a plurality of pixel transistors, wherein the short axis length of the linear laser spot is d, , L is the laser spot scanning speed V, and the laser emission pulse frequency is f, the controller sets the laser emission pulse frequency f in the range of V / L <f <V / d. The eighteenth feature is to perform laser emission.

  Further, the present invention provides the laser irradiation method according to any one of the thirteenth to sixteenth features, wherein the irradiation object is a flat display including a plurality of pixel transistors, the short axis length of the linear laser spot is d, and the laser spot A nineteenth feature is that laser emission is performed by setting V / d <f in a range where V is a scanning speed and f is a laser emission pulse frequency.

  According to a twentieth feature of the present invention, in the laser irradiation method according to any one of the twelfth to sixteenth features, the laser light source is a semiconductor laser element that emits laser light having a laser wavelength of 370 nm to 480 nm.

  In addition, in the laser irradiation method according to any one of the twelfth to sixteenth aspects, the present invention is characterized in that the laser light source is a semiconductor laser element that emits laser light having a laser wavelength of 600 nm to 850 nm.

  In addition, in the laser irradiation method of any of the twelfth to sixteenth aspects, the present invention is characterized in that the laser light source is a solid-state laser that emits laser light having a laser wavelength of 350 nm to 550 nm.

  According to the above-described features, the present invention enables the control unit to move the moving stage on which the irradiation object is mounted at a predetermined speed and to output individual laser output values emitted from the plurality of laser light sources by the plurality of driver circuits over time. The irradiation target is irradiated by irradiating the irradiation target with the linear laser spot while temporally changing the laser profile indicating the displacement of the laser output value in the longitudinal direction of the linear laser spot. It is possible to prevent the occurrence of linear crystal spots and luminance spots.

  Hereinafter, a laser irradiation apparatus and a laser irradiation method according to an embodiment of the present invention will be described in detail with reference to the drawings. 1 and 2 are diagrams for explaining the modification effect by the laser irradiation method according to the present embodiment, FIG. 3 is a diagram showing a basic configuration of the laser irradiation apparatus according to the present embodiment, and FIG. 4 is a laser spot according to the present embodiment. FIG. 5 is a diagram for explaining the output timing of the laser spot according to the present embodiment, FIG. 6 is a diagram showing an operation flow of laser irradiation according to the present embodiment, and FIG. 9 is a diagram for explaining the present embodiment. FIG. 10 and FIG. 11 are diagrams for explaining the laser spot minor axis width and profile update period according to the present embodiment, and FIG. 12 is a general substrate. FIG. 13 is a diagram illustrating the operation of the laser irradiation apparatus according to the present embodiment.

[Constitution]
As shown in FIG. 3, the basic configuration of the laser irradiation apparatus according to the present embodiment includes a semiconductor laser element group 31 including a plurality of blue semiconductor laser elements 30A to 30F that emit blue laser light, and a semiconductor laser element group 31. A plurality of optical fibers 32 for guiding emitted laser light, and a linear laser spot 45 is formed based on the laser light emitted from the plurality of optical fibers 32, and the laser spot 45 is irradiated from an irradiation object such as a silicon film. An optical head 39 for detecting the light intensity of the reflected light, a plurality of laser drivers 43A to 43F for driving the plurality of blue semiconductor laser elements 30A to 30F, and a basic drive current applied to the blue semiconductor laser elements 30A to 30F. The base power D / A converter 40 for outputting the signal and the superimposed drive applied to the blue semiconductor laser elements 30A to 30F Superimposing power D / A converter 41 for outputting a current, and analog switches 44A to 44F for switching whether or not the driving current from superimposing power D / A converter 41 is superimposed on laser drivers 43A to 43F; The base power D / A converter 40 and the superimposed power D are input with the pulse generator 42 that outputs the superimposed pulse 47 that instructs the switching of the analog switches 44A to 44F and the light intensity from the optical head 39 as inputs. An MPU 39 that controls the A / A converter 41 and the pulse generator 42, a personal computer (PC) 46 that controls the MPU 39, and an irradiation object are mounted, and the irradiation object is orthogonal to the longitudinal direction of the linear laser spot 45. And a moving stage (not shown) that moves at a predetermined speed in the direction. That. In this specification, the laser spot shape is described as a linear shape, but it may be referred to as an ellipse, and this laser spot shape is a shape that can irradiate a plurality of continuous pixels of an irradiation object at a time. good.

  The optical head 39 includes a linear bundle 33 that combines the output ends of the plurality of optical fibers 32, and a laser beam emitted from the output ends of the plurality of optical fibers 32 to receive an inner core portion and a cladding portion. A homogenizer (: an optical module for homogenizing the profile of the laser beam on the irradiated surface, which is a waveguide in this example) 34 that emits the laser beam with a spatial intensity distribution that is smoothed by the difference in refractive index of the laser beam, and the homogenizer 34 Reflected from the irradiation object such as a silicon film, a beam splitter 35, a convex lens 37 for condensing the laser light transmitted through the beam splitter 35 to form a linear laser spot 45, and A convex lens 37 that receives and collects reflected light by the beam splitter 35, and light of the reflected light that is collected by the convex lens 37. And an optical sensor 38. for detecting a degree.

  As shown in FIG. 4, the laser power output from the blue semiconductor laser elements 30A to 30F is the base power Pb (reference numeral 50) output by the basic drive current output from the base power D / A converter 40. The superimposed power Pa (reference numeral 51) is superimposed on the base power 50 by the superimposed drive current output from the power D / A converter 41. The superimposed power Pa is preferably in the range of 2% to 50% of the base power Pb.

  For the semiconductor laser elements 30A to 30F, in the case of a TFT silicon film for display, particularly in the case of a TFT silicon film for display, the laser wavelength may be selected. This is because the shorter the wavelength, the light energy is absorbed on the surface of the silicon film, and the longer the wavelength, the deeper penetration of the silicon film and the overheating. If the wavelength is selected according to the film thickness, the light energy can be efficiently converted into thermal energy. For example, a laser wavelength of 370 nm to 480 nm is desirable when the silicon film thickness is ˜100 nm, and a laser wavelength of 600 nm to 850 nm is desirable when the silicon film thickness is 50 nm to 1 μm. Further, when the silicon film thickness is ˜200 nm, a solid laser element that emits laser light having a laser wavelength of 350 nm to 550 nm may be used.

  The pulse generator 42 individually controls the laser output values from the plurality of blue semiconductor laser elements 30A to 30F using the base power Pb and the superimposed power Pa. The output power values are shown in FIG. As shown in FIG. 4, the output timing 20A of the laser element 30A is set in a pulse shape between time E2 to E3, time E5, and time E9 to E10, and the output timing 20B of the laser element 30B is set to time E1 and time E3 to E4. During the period of time E7-9, between time E12-E13, and at time E16, the pulse timing is set, and the output timing 20C of the laser element 30C is between time E4-E6, time E8, time E10-E11, time E14- It is set in a pulse form during E15, and the output timing 20D of the laser element 30D is between time E1 and E2, between time E5 and 7 and time. 11 to E12, set to pulses between times E15 to E16, the output timings of the other laser elements are the same, and the sum of the laser output values at each time E is set to a predetermined value. is doing.

  That is, the pulse generator 42 according to the present embodiment randomly changes the output value with time of laser output from the plurality of blue semiconductor laser elements 30A to 30F by switching between application and non-application of the superimposed power Pa. And the total sum of all the laser outputs at any time E is set to be a constant value, so that the total laser outputs from the plurality of blue semiconductor elements forming the linear laser spots at the times E1 to E16. The laser output value output from each blue semiconductor element can be randomly changed while keeping the value constant.

  Furthermore, the MPU 39 according to the present embodiment determines and controls the laser profile update period and the laser spot scanning speed in accordance with the pixel pitch width of the pixel portion of the display to be irradiated. The relationship will be described with reference to FIGS.

  First, as shown in FIG. 11 in which a display that is an irradiation target is an enlarged pixel portion, one pixel 97 is an R (red) pixel 93, a G (green) pixel 94, and a B (blue) pixel that are light emitting elements. 95 and pixel transistors 90 to 92 for driving these pixels 93 to 95. When scanning the laser spot in the X direction 100, the X direction pixel interval is an interval indicated by reference numeral 99, and the laser spot is set to Y. When scanning in the direction 100, the Y-direction pixel interval is the interval indicated by reference numeral 96.

  Here, assuming that the pixel interval (transistor interval) is L and the spot scanning speed is V, the pulse interval 21 of the laser beam irradiated according to the present embodiment is expressed as L / V and is changed for each pixel interval. The upper frequency limit is V / L. Since the frequency f range is easily recognized when the linear spots are continuous for about 5 pixels or more, the frequency f range of the superimposed pulse is preferably [V / 5L <f <V / L]. However, it is not limited to this.

  FIG. 10 is a diagram for explaining a laser spot minor axis width and a profile update period according to another example. In the example of FIG. 11 described above, an example in which the upper limit of the superposition frequency is determined by the pixel interval has been described. However, as a condition for preventing the formation of line spots, the short axis width of the laser spot is basically used and the short axis distance is moved each time. The beam profile may be updated. That is, as shown in FIG. 10, when the laser spot 85 is scanned in the direction of the arrow 88 at the scanning speed V, the laser minor axis width is d (reference numeral 89), and the minor axis width movement positions 86, 87. The laser profile may be changed to V / d, which corresponds to the upper limit of the superposition frequency. Since the lower limit may be obtained by changing the profile for each pixel L, the lower limit frequency is expressed as [V / L]. Therefore, the range of the superimposed pulse frequency f is preferably [V / L <f <V / d]. Further, the beam profile may be updated at least once while moving the minor axis width without depending on the pixel interval. In this case, the superimposed pulse frequency f is [V / d <f].

  As described above, the laser irradiation apparatus according to the present embodiment is configured to switch the laser profile according to the interval between the pixels to be modified of the irradiation object and the scanning speed.

[Operation]
As shown in FIG. 6, the laser irradiation apparatus configured as described above has a step 102 in which the pixel pitch width (L) of the irradiation object is input from the personal computer 46 to the MPU 39, and a base that becomes the basic power value described above. By executing step 103 for inputting the power Pb50 and the individual values of the superimposed power Pa51 to be added to the basic power value, and step 104 for inputting the scanning speed V of the laser spot and the spot overlap width D described above, Necessary parameters for driving the laser irradiation apparatus according to the embodiment are registered as initial information.

  Next, in this apparatus, the MPU 39 to which the initial information has been input calculates the step 105 of the superimposed pulse frequency, and moves the optical head 39 to a predetermined position on a glass substrate (not shown) on which the moving stage is mounted. In step 107, the output laser value (reference drive current) of the base power D / A converter 40 is set by the MPU 39, and similarly, the output laser value (superimposed drive current) of the superimposed power D / A converter 41 is set. Step 108 is executed.

  Next, in this apparatus, the base power D / A converter 40 and the superimposed power D / A converter 41 generate a drive current having a predetermined output value in accordance with the conditions set in the above-described steps, and the pulse generator 42 in FIG. As described above, the on / off control of the analog switches 44A to 44F controls the step 109 for starting the emission of laser light whose output value changes randomly, and the laser spot formed by the emission of the laser light on the glass substrate. Step 110 for scanning from one end of the glass substrate in the X direction at a speed V, Step 111 for detecting and stopping that the laser spot has reached the other end on the glass substrate, and scanning of a predetermined region of the glass substrate are completed. Step 112 for ending the process when it is determined that scanning of the predetermined area is completed, When it is determined in step 112 that scanning has not ended, the laser spot is moved in the Y direction, scanning of the next region of the glass substrate is started while maintaining the overlap width D, and the process returns to step 111. Are executed sequentially.

  Through these steps, the laser irradiation apparatus according to the present embodiment scans a predetermined area with the laser power obtained by randomly applying the superimposing power Pa51 to the base power Pb50 while monitoring the total laser output value by the optical sensor 38 and keeping it constant. A linear crystal caused by unevenness of the laser output value distribution in the longitudinal direction of the linear laser spot is performed by keeping the overlap width D when scanning the next adjacent scanning region (laser irradiation) at a predetermined value. It is possible to prevent the occurrence of spots and luminance spots.

  Further, the depth of the superposed pulse (superimposed power amount with respect to the base power) is 50% ≦ (Pb / (Pb + Pa) × 100%) ≦ 98 because of both limitations for obtaining the effect of the present invention and avoiding the deterioration of the profile unevenness. % Is desirable.

  The modification effect by laser irradiation according to this embodiment will be described with reference to FIG. In the laser irradiation performed by the above-described processing procedure, the profile of the laser output changes according to the times E1 to E3 as time passes, and the linear laser spot 13 by this profile is indicated by an arrow 14. By scanning in the direction, the generation positions of the pixel transistor 15 that has been sufficiently reformed indicated by hatching in the drawing and the pixel transistor 16 that is relatively insufficiently reformed indicated by white lines are represented as time passes. By randomly changing in the Y direction, the pixel transistors 15 and 16 are not continuously generated in the X direction as in the prior art, and the occurrence of linear crystal spots and luminance spots that can be visually recognized is prevented. Can do.

  Further, as shown in FIG. 2, the laser irradiation with the overlap width D in the adjacent region described above is an overlapping portion where the linear laser spot 13a scanned in the direction of the arrow 14a and the linear laser spot 13b scanned in the direction of the arrow 14b overlap. In this embodiment, the modulation width of the drive pulse of the semiconductor laser element corresponding to 133 is set large. That is, in this example, in the major axis direction of the linear laser spot, the pulse modulation width of the semiconductor laser element contributing to the end of the linear laser spot is larger than the central portion (laser modulation width [base power value Pb and superimposed power By deepening the difference from the value Pa], the laser spot in the overlap portion 133 can obscure the crystal state compared to the central portion, and the crystal spot and the brightness spot can be “blurred”. Generation of linear crystal spots and luminance spots in the portion 133 can be prevented. When the pulse width of the superimposed power value Pa added to the base power value Pb is Pw, the pulse modulation width at the center is 60% ≦ (Pw / (Pb + Pa) × 100%) ≦ 98%. It is desirable to set the width to about 50% ≦ (Pw / (Pb + Pa) × 100%) ≦ 98%. The semiconductor laser elements contributing to the output values at both ends of the linear laser spot are, for example, the semiconductor lasers 30F and 30E and the semiconductor laser elements 30B and 30A in FIG. A laser element is another semiconductor laser element.

  In the present embodiment, by increasing the superposition power value Pa at both ends of the linear laser spot as compared with the central portion, the unevenness of the profile can be increased (steep) in terms of time / space. By performing the processing, the crystal state differs in units of micro space on the silicon film surface, and when it is observed macroscopically, it can be seen uniformly, and it can be in a state in which spots are scattered, that is, a “blurred” state. In other words, as in this embodiment, by increasing the pulse modulation width applied to the semiconductor laser element that affects both ends of the linear laser spot, this corresponds to increasing the difference in crystal state in a minute space unit. , "Blur" can be strengthened. In this way, it is desirable to increase the “blurring” effect in order to cut off the continuity of the linear spots at the boundary between the beam overlapping portions.

  Therefore, although the laser irradiation apparatus according to the present embodiment generates crystal spots and luminance spots in the center portion in the longitudinal direction of the linear laser spot, the crystal spots and luminance spots are intermittently scattered, so that The occurrence of crystal spots and brightness spots can be prevented, and the occurrence of linear crystal spots and brightness spots can also be prevented by increasing the pulse modulation width in the overlap portion 133.

  In the embodiment, the example in which the focal point control of the laser spot is not performed has been described. However, the reflected light amount of the reflected light from the irradiation object is detected, and the reflected light amount of the objective lens is maximized during this operation. It is also possible to add an autofocus function so that the laser spot shape does not change. Furthermore, in the above-described embodiment, an example in which the entire surface of the glass substrate is irradiated with a laser has been described. However, the present invention is not limited to this, and it may be configured to irradiate only the pixel portion of the transistor formation portion. .

  In the above-described embodiment, the example in which the laser output value output from each semiconductor laser element is changed by applying the superimposed power to the base power using the analog switch has been described. However, the present invention is limited to this. Instead, for example, the relationship between the drive current and the laser output value for each semiconductor laser element may be measured in advance, and the MPU may randomly change the laser output value for each driver.

The figure for demonstrating the modification effect of the laser irradiation method by one Embodiment of this invention. The figure for demonstrating the modification effect of the laser irradiation method by one Embodiment of this invention. The figure which shows the basic composition of the laser irradiation apparatus by this embodiment. The figure which shows the base and superimposition power of the laser spot by this embodiment. Explanatory drawing of the output timing of the laser spot by this embodiment. The figure which shows the operation | movement flow of the laser irradiation by this embodiment. The figure for demonstrating the malfunction of the laser irradiation apparatus by a prior art. The figure for demonstrating the malfunction of the display manufactured by the laser irradiation apparatus of the prior art. The figure for demonstrating the malfunction of the display manufactured by the laser irradiation apparatus of this embodiment. The figure for demonstrating the laser spot short-axis width and profile update period by this embodiment. The figure for demonstrating the laser spot short-axis width and profile update period by other embodiment. The figure which shows the modification | reformation of the silicon film by the general structure on a board | substrate, and laser irradiation. The figure for demonstrating operation | movement of the laser irradiation apparatus by this embodiment. The figure for demonstrating the distribution of the laser output value of the longitudinal direction of the linear laser spot by a prior art, and the state of the modified irradiation target object.

Explanation of symbols

  30A to 30F: Blue semiconductor laser element, 43A to 43F: Laser driver, 44A to 44F: Analog switch, 12: Laser profile, 13: Linear laser spot, 15 and 16: Pixel transistor, 20A to 20D: Output timing, 21 : Pulse interval, 31: Semiconductor laser element group, 32: Optical fiber, 33: Linear bundle, 34: Homogenizer, 34: Light guide plate, 35: Beam splitter, 37: Convex lens, 38: Optical sensor, 39: Optical head, 40 : A / D converter, 41: A / D converter, 42: pulse generator, 45: linear laser spot, 46: personal computer, 47: superimposed pulse, 50: base power, 60: glass substrate, 61: display, D : Spot overlap width.

Claims (22)

  In a laser irradiation apparatus for modifying an irradiation object by irradiating the irradiation object with a linear laser spot and scanning in the short axis direction of the linear laser spot, the linear laser is scanned while scanning the irradiation object. Laser irradiation device that changes the beam profile in the long axis direction of a spot with time. A laser irradiation apparatus that forms a linear laser spot by emitting a plurality of laser beams emitted from a plurality of laser light sources through a light guide plate, and irradiates the irradiation target with the laser spot,
A plurality of laser light sources that emit laser light;
A plurality of driver circuits for driving the laser light sources to emit laser light emitted from the plurality of laser light sources at an arbitrary output value;
A moving stage for moving the irradiation object in a direction perpendicular to the longitudinal direction of the linear laser spot;
A controller that moves the moving stage at an arbitrary moving speed and independently controls laser output values emitted from a plurality of laser light sources through the plurality of driver circuits;
A laser irradiation apparatus in which the control unit independently changes a laser output value emitted from each of a plurality of laser light sources by the plurality of driver circuits as time passes while moving the moving stage at a predetermined speed.   3. The laser according to claim 2, wherein the control unit independently controls each of the plurality of driver circuits so that a sum of laser output values emitted from the plurality of laser light sources through the plurality of driver circuits at an arbitrary time is maintained at a predetermined value. Irradiation device.   The control unit emits light from a plurality of laser light sources by superimposing a superimposition power Pa that is a laser output value in a range of 2% to 50% of the base power Pb on a base power Pb that is a predetermined laser output value. The laser irradiation apparatus according to claim 2 or 3, wherein the laser output value to be changed is changed independently over time.   When the pulse width of the laser output is Pw, the control unit sets the pulse modulation width of the laser light source that contributes to the laser output values at both ends of the linear laser spot as 50% ≦ (Pw / (Pb + Pa) × 100. %) ≦ 98%, and the pulse modulation width of the other laser light sources excluding the laser light sources contributing to the laser output values at both ends is set to 60% ≦ (Pw / (Pb + Pa) × 100%) ≦ 98 5. The laser irradiation apparatus according to claim 4, wherein the pulse modulation width of the laser light source at both ends is controlled to be larger than the pulse modulation width at the center by setting in the range of%. When the irradiation object is a flat display including a plurality of pixel transistors, when the pixel transistor interval of the flat display is L, the laser spot scanning speed is V, and the laser emission pulse frequency is f,
The laser irradiation apparatus according to any one of claims 2 to 5, wherein the control unit performs laser light emission by setting a laser light emission pulse frequency f in a range of V / (5L) <f <V / L. The irradiation object is a flat display including a plurality of pixel transistors, the short axis length of the linear laser spot is d, the interval between the pixel transistors is L, the scanning speed of the laser spot is V, and the laser emission pulse frequency is f. When
The laser irradiation apparatus according to any one of claims 2 to 5, wherein the control unit performs laser light emission by setting a laser light emission pulse frequency f in a range of V / L <f <V / d.   The irradiation object is a flat display including a plurality of pixel transistors, where V / d <when the short axis length of the linear laser spot is d, the scanning speed of the laser spot is V, and the laser emission pulse frequency is f. The laser irradiation apparatus according to claim 2, wherein the laser emission is performed by setting in a range of f.   9. The laser irradiation apparatus according to claim 1, wherein the laser light source is a semiconductor laser element that emits laser light having a laser wavelength of 370 nm to 480 nm.   9. The laser irradiation apparatus according to claim 1, wherein the laser light source is a semiconductor laser element that emits laser light having a laser wavelength of 600 nm to 850 nm.   The laser irradiation apparatus according to any one of claims 1 to 8, wherein the laser light source is a solid-state laser that emits laser light having a laser wavelength of 350 nm to 550 nm.   In a laser irradiation method for modifying an irradiation object by irradiating the irradiation object with a linear laser spot and scanning in the short axis direction of the linear laser spot, the linear laser is scanned while scanning the irradiation object. A laser irradiation method in which the beam profile in the major axis direction of a spot is changed with time. A plurality of laser light sources that emit laser light, a plurality of driver circuits that drive the laser light sources to emit laser light emitted from the plurality of laser light sources at an arbitrary output value, and an object to be irradiated are linear A moving stage that moves in a direction orthogonal to the longitudinal direction of the laser spot, and a control that moves the moving stage at an arbitrary moving speed and independently controls the laser output values emitted from the plurality of laser light sources through the plurality of driver circuits. A laser irradiation apparatus that forms a linear laser spot by emitting a plurality of laser beams emitted from a plurality of laser light sources through a light guide plate and irradiating the irradiation target with the laser spots. A laser irradiation method comprising:
A laser irradiation method in which the control unit independently changes each laser output value emitted from each of the plurality of laser light sources by the plurality of driver circuits with time while moving the moving stage at a predetermined speed.   14. The laser according to claim 13, wherein the control unit independently controls each of the plurality of driver circuits so that a total sum of laser output values emitted from the plurality of laser light sources through the plurality of driver circuits at an arbitrary time is maintained at a predetermined value. Irradiation method.   The control unit emits light from a plurality of laser light sources by superimposing a superimposition power Pa that is a laser output value in a range of 2% to 50% of the base power Pb on a base power Pb that is a predetermined laser output value. The laser irradiation method according to claim 13 or 14, wherein the laser output value to be changed is changed independently with time.   When the pulse width of the laser output is Pw, the control unit sets the pulse modulation width of the laser light source that contributes to the laser output values at both ends of the linear laser spot as 50% ≦ (Pw / (Pb + Pa) × 100. %) ≦ 98%, and the pulse modulation width of the other laser light sources excluding the laser light sources contributing to the laser output values at both ends is set to 60% ≦ (Pw / (Pb + Pa) × 100%) ≦ 98 The laser irradiation method according to claim 15, wherein the pulse modulation width of the laser light source at both ends is controlled to be larger than the pulse modulation width at the central portion by setting in a range of%. When the irradiation object is a flat display including a plurality of pixel transistors, when the pixel transistor interval of the flat display is L, the laser spot scanning speed is V, and the laser emission pulse frequency is f,
The laser irradiation method according to any one of claims 13 to 16, wherein the control unit performs laser light emission by setting a laser light emission pulse frequency f in a range of V / (5L) <f <V / L. The irradiation object is a flat display including a plurality of pixel transistors, the short axis length of the linear laser spot is d, the interval between the pixel transistors is L, the scanning speed of the laser spot is V, and the laser emission pulse frequency is f. When
The laser irradiation method according to any one of claims 13 to 16, wherein the control unit performs laser light emission by setting a laser light emission pulse frequency f in a range of V / L <f <V / d.   The irradiation object is a flat display including a plurality of pixel transistors, where V / d <when the short axis length of the linear laser spot is d, the scanning speed of the laser spot is V, and the laser emission pulse frequency is f. The laser irradiation method according to any one of claims 13 to 16, wherein the laser emission is performed by setting in a range of f.   The laser irradiation method according to claim 12, wherein the laser light source is a semiconductor laser element that emits laser light having a laser wavelength of 370 nm to 480 nm.   The laser irradiation method according to claim 12, wherein the laser light source is a semiconductor laser element that emits laser light having a laser wavelength of 600 nm to 850 nm.   The laser irradiation method according to claim 12, wherein the laser light source is a solid-state laser that emits laser light having a laser wavelength of 350 nm to 550 nm.

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