JP6994947B2 - Laser annealing method and laser annealing equipment - Google Patents

Description

The present invention relates to a laser annealing method and a laser annealing device that irradiate a object to be processed with a laser beam to anneal the object to be processed.

Conventionally, for example, when a thin film silicon substrate on glass is crystallized by a laser beam, as mentioned in Patent Document 1, a line beam is irradiated while moving relatively in one direction with respect to the substrate. The entire surface of the substrate is crystallized (hereinafter referred to as the line beam method). Here, the intensity distribution of the line beam is composed of a flat portion which is a region where the intensity is flat and an inclined portion where the intensity is inclined in the beam cross-sectional profile. The moving speed of the line beam is set so that it is irradiated 20 times.
FIG. 9 shows a plan view (FIG. A) and a beam cross-sectional profile (FIG. B) of the beam 900. The beam has a flat portion 901 and an inclined portion 902.

The process of crystallization by the line beam can be generally described below based on FIG. 6 (A).
In the line beam 800, the beam intensity is inclined around the uniform energy region 801 and has energy intensity gradient regions 803 and 803 at the end in the long direction, and energy intensity at both ends in the scanning direction. It has gradient regions 802 and 802.
When the line beam 800 is irradiated to the thin film silicon 810, as shown in FIG. 6B, the thin film silicon 810 is melted in the irradiated portion corresponding to the energy region 801 where the intensity distribution is uniform, and the molten pool 820 is formed. Will be done.

Most of the molten pool 820 grows vertically from the interface between silicon and glass, and grows slightly horizontally at the end of the molten pool 821. At this time, the molten silicon end portion 821 expands when the molten silicon moves in the horizontal direction and the silicon solidifies, so that the portion expands as shown in FIG. 7 and the portion becomes thick locally. This is referred to as a thickened portion 830 at the beam end. The height of the thickened portion 830 is considered to depend on the depth of the molten pool 820 and the shape of the solid-liquid interface of the molten pool end portion 821, and therefore depends on the gradient degree of the energy intensity gradient region 802 of the irradiation beam.
As shown in FIG. 7, the width of the thickened portion 830 is about 20 μm, and the height difference is about 10 μm. Since this is when the film is irradiated with a specific energy intensity and intensity gradient, the width and height of the thickened portion do not always have this width and height difference.

As shown in FIG. 6B, when the beam irradiation area was moved and the second line beam 800a was irradiated, the portion irradiated on the thickened portion 830 became flat due to remelting. A molten pool 820a is formed, and a new thickened portion is formed by the second irradiation.

The crystal grain size gradually increases with multiple irradiations, and when a certain number of irradiations is exceeded, the crystal grains become uniform. Many speculations have been proposed for the mechanism by which the crystal grains are homogenized, but as an experimental fact, it is known that it is necessary to make the crystal grains uniform multiple times, as shown in FIG. At the optimum energy density (315 mJ / cm ² in FIG. 8), the grain size becomes constant after 5 times or more.

Due to the above crystallization process, the irradiation conditions in the line beam method are generally carried out under the following conditions.
(1) As the number of irradiations increases, the crystal grains become larger and uniform, and the increase in crystal grains is saturated by irradiation more than a specific number of times. Therefore, it is common to irradiate 5 times or more.
(2) Irradiation is performed at a feed pitch similar to the width of the thickened portion so that the irradiation is performed at the width of the thickened portion at the end of the molten pool. The feed pitch is generally 10 to 20 μm. Irradiation with a smaller feed pitch reduces the height difference, but it hinders productivity and is difficult to reduce.
(3) Since the energy intensity gradient region 803 at the end in the major axis direction of the line beam is larger than the energy intensity gradient region 802 in the minor axis direction, there is a difference in the crystal growth process, and it is generally not used in products. Is.

As described above, in the line beam method, the thickened portion is periodically formed, and the height difference of the film thickness becomes large. Generally, it is known that the characteristics of a thin film depend on the film thickness (for example, Non-Patent Document 1). Therefore, there is a problem that the height difference of the film thickness causes the performance variation of the thin film, and therefore the display becomes uneven. Further, since the crystal growth direction of the thickened portion is different from that of the uniform energy portion, it is considered that there is a slight difference in the crystal shape, which causes a difference in the characteristics of the thin film. For this reason, it is considered that the height difference can be reduced or the crystal shape can be made almost the same by reducing the feed pitch with respect to the width of the thickened portion, but the productivity is remarkably high. It is not a viable solution because it is reduced.

Further, the thickened portion at the end of the long axis of the line beam is different from that generated on the short axis, and there is a problem that it cannot be used for products such as displays. In particular, in the line beam method, since the long axis end is continuously irradiated, the obtained crystallized silicon becomes different from other regions.

As described above, in the line beam method, since the inclined portion in the long direction of the long axis cannot be used in the product, the method shown in Patent Document 2 has been proposed as a method that may change to the line beam method.
In this method, a laser beam having a quadrilateral beam cross-sectional shape is used, and when the laser beam is irradiated, any side of the quadrilateral in the beam cross-sectional shape has a predetermined angle with the scanning direction on the object to be processed. It is supposed to irradiate a pulsed laser.
According to this method, it is possible to crystallize the entire surface of the substrate by reducing the number of irradiations and the area by the inclined portion at the same location by not continuously forming the boundary between the irradiated and non-irradiated surfaces.

Japanese Unexamined Patent Publication No. 2002-376923 Japanese Patent No. 3534069

Published by Kogyo Chosakai, by Ikuhiro Ukai, "All about Thinlet Technology", P65

As described above, in the conventional line beam method, there is a problem that the quality of the annealing treatment is deteriorated due to the formation of the thickened portion.
Also, even in the method using a laser beam with a quadrilateral beam cross section, if the interval between the quadrilateral feed pitches is wide, the thickened portion generated at the boundary causes variations in the performance of the thin film as in the line beam method. It becomes.
In addition, in order to reduce the feed pitch, it is necessary to reduce the size of the quadrilateral, and high-power lasers such as excimer lasers are difficult to use due to the high energy per pulse, and productivity is low. There is a problem.

The present invention has been made in the background of the above circumstances, and it is possible to reduce the harmful effect of the energy intensity gradient portion in the beam cross section of the laser beam, to utilize the object to be treated irradiated with the laser beam with good yield, and to use the laser beam size. It is an object of the present invention to provide a laser annealing method and a laser annealing apparatus capable of performing laser processing with high productivity without limiting the size of the laser.

That is, among the laser annealing methods of the present invention, the first invention has an ambient intensity gradient region having an intensity gradient in which the intensity decreases outward in the beam cross section on the irradiation surface of the object to be treated. A beam of pulsed laser light having an intensity flat region having a flat intensity inside the ambient intensity gradient region is positioned at M points (M is an integer of 2 or more) on the object to be processed, and the object to be processed. It has an irradiation step of irradiating a body while relatively scanning the beam and irradiating the same portion of the object to be processed N times (N is an integer of 2 or more).
The beam is adjacent to the beam in the beam cross section on the irradiation surface, where W is the length of the intensity flat region in the scanning direction and L is the length of the intensity flat region in the orthogonal direction orthogonal to the scanning direction. Sequentially located at a distance of 2 W-W / N in the scanning direction and L / N in the direction orthogonal to the scanning direction, and the feed pitch per beam irradiation in the scanning direction is W. It is characterized by.

In the second method of laser annealing of the present invention, in the first invention, after the irradiation step, the relative irradiation position of the M point of the beam with respect to the object to be processed is set in a direction orthogonal to the scanning direction. It has an irradiation position changing step of changing by a distance of (M + 1) × (L / N), and then the irradiation step is executed according to the changed irradiation position, and these irradiation steps and the irradiation position changing step are alternated. It is characterized by repeating to.

In the third method of laser annealing of the present invention, in the first invention, in the irradiation step, a plurality of beams located at the M location are set as one beam group, and the beam groups are set as a plurality of sets and adjacent to each other. The set of beam groups is positioned at an interval of (M + 1) × (L / N) in a direction orthogonal to the scanning direction, and the beam in each beam group is scanned relative to the object to be processed. It is characterized in that the object to be treated is irradiated at the same time.

In the fourth laser annealing method of the present invention, in any one of the first to third inventions, the pulsed laser beam is applied to the M points (M is two or more) on the object to be processed. A plurality of laser light sources to be positioned at each of the integers) are prepared, the beam from each laser light source is positioned at the M location for each laser light source, and the beam sequence at the M location by each laser light source is a row of adjacent beams. It is characterized in that it is positioned at an interval of (M + 1) × (L / N) in a direction orthogonal to the scanning direction.

The fifth method of laser annealing of the present invention is characterized in that, in any one of the first to fourth inventions, the beam has a rectangular shape in the cross-sectional shape of the beam on the irradiation surface.

The sixth method of laser annealing of the present invention is characterized in that, in the fifth aspect of the present invention, each side of the beam is along a scanning direction or a direction orthogonal to the scanning direction.

The seventh method of laser annealing of the present invention is characterized in that, in any one of the first to sixth aspects of the present invention, the object to be treated is an amorphous silicon film.

The eighth laser annealing apparatus of the present invention has an ambient intensity gradient region having an intensity gradient in which the intensity decreases outward in the beam cross section on the irradiation surface of the object to be treated, and the ambient intensity gradient region has a peripheral intensity gradient. A laser annealing device that irradiates the object to be processed with a pulsed laser beam having a flat intensity area having a flat intensity inside.
A laser light source that outputs the laser beam and
It has an optical system that shapes the laser beam and guides the shaped beam of the laser beam to the object to be processed to irradiate the object to be processed.
The optical system has a plurality of beams on the object to be processed, in which the length in the scanning direction in the intensity flat region is W and the length in the direction orthogonal to the scanning direction is L, and the beams are in the scanning direction. 2W-W / N, and has a partially transmissive portion for positioning M (M is an integer of 2 or more) at intervals of L / N in a direction orthogonal to the scanning direction.
Further, it has a moving device that moves the beam irradiated to the object to be processed relative to the object to be processed.
The moving device is characterized by having a mechanism for performing the relative movement so that the feed pitch per irradiation of the beam in the scanning direction is W.

In the eighth aspect of the present invention, the laser light source of the ninth aspect of the present invention outputs the laser beam repeatedly at a frequency RHz.
The moving device is characterized in that the velocity V in the scanning direction satisfies V = W × R.

In the eighth or ninth aspect of the present invention, the tenth laser annealing device is the moving device, and the moving device is the object to be processed at a distance of (M + 1) × (L / N) in a direction orthogonal to the scanning direction. It is characterized by having a mechanism for changing the relative position of the beam with respect to.

The eleventh laser annealing apparatus of the present invention has an ambient intensity gradient region having an intensity gradient in which the intensity decreases outward in the beam cross section on the irradiation surface of the object to be treated, and the ambient intensity gradient region has a peripheral intensity gradient. A laser annealing device that irradiates the object to be processed with a pulsed laser beam having a flat intensity area having a flat intensity inside.
A plurality of laser light sources that output the laser light, respectively, and
It has an optical system that shapes each laser beam and guides the shaped beam of the laser beam to the object to be processed to irradiate the object to be processed.
The optical system has a beam having a length in the scanning direction of W and a length in the direction orthogonal to the scanning direction L on the object to be processed for each laser light source, and the beam is the scanning. It has a partially transparent portion for arranging M columns (M is an integer of 2 or more) at intervals of 2 W-W / N in the direction and L / N in the direction orthogonal to the scanning direction.
In the partially transmitted portion, the array of M adjacent beams corresponding to each laser light source is displaced by a distance of (M + 1) × (L / N) in a direction orthogonal to the scanning direction, and the object to be processed is processed. It is set to be located on top and
Further, it is characterized by having a moving device for moving the beam irradiated to the object to be processed relative to the object to be processed.

In the eleventh invention, the twelfth laser annealing apparatus has n units of the plurality of laser light sources, and the mobile apparatus has (M + 1) × (L) in a direction orthogonal to the scanning direction. It is characterized by having a mechanism for changing the relative position of the beam with respect to the object to be processed at a distance of / N) × n.

According to the present invention, by reducing the interval of the energy intensity gradient region, the height difference due to the thickened portion can be reduced, and a uniform crystal shape and surface can be formed over the entire surface of the object to be treated. In addition, it becomes possible to reduce the size of the device and provide a device at a lower price as compared with the conventional one.

It is a schematic diagram which shows the laser annealing apparatus of one Embodiment of this invention, FIG. 1A is a plan view of the laser annealing apparatus 1, and FIG. It is a front view of the annealing apparatus 1. Similarly, it is a figure which shows the plane of the partial transmission part. Similarly, it is a conceptual diagram which shows the state of laser light irradiation to a substrate. Similarly, it is a detailed view which shows the state of laser light irradiation to a substrate. Similarly, it is a plane conceptual diagram which shows the modification example of the partial transmission part. It is a figure explaining an irradiation state, an energy distribution, and a crystallization process in a conventional line beam format. It is an enlarged view which shows the shape of the substrate surface layer after solidification by the conventional laser light irradiation. It is a graph which shows the relationship between the number of pulses and the average particle diameter with respect to the conventional irradiation energy. It is a figure explaining the energy intensity distribution in the beam cross section of a conventional square.

Hereinafter, the laser annealing apparatus according to the embodiment of the present invention will be described with reference to FIG.
The laser annealing device 1 has a laser light source 100 that outputs a pulsed laser beam, a substrate mounting table 120 on which the substrate 2 is placed, and an optical system 110 that guides the laser beam output from the laser light source 100. There is. In this example, the optical system 110 has a mirror 111, a mirror 113, a mirror 114, mirrors 116a, 116b, a homogenizer 117, a partial transmission portion 118, and a projection lens 119 purely from the side close to the laser light source 100. Here, the partially transparent portion 118 corresponds to the shaping portion of the present invention.
In the present invention, each optical member of the optical system is not limited to a specific one.

Further, optical system support bases 130 and 130 are installed on both sides of the substrate mounting base 120, and an erection portion 131 is provided so as to bridge between the optical system support bases 130 and 130. The erection portion 131 is movable in the long direction (here, the Y direction) of the optical system support bases 130 and 130. The erection unit 131 is moved by a drive device (not shown). The erection portion 131 is provided with a movable optical unit 132, and the movable optical unit 132 can be moved in the long direction (here, the X direction) of the erection portion 131. The movement of the movable optical unit 132 is performed by a drive device (not shown).

The reflection surface of the mirror 113 is located in the reflection direction of the mirror 111, is fixed to the erection portion 131, and moves together with the erection portion 131.
The movable optical unit 132 is located in the reflection direction of the mirror 113, and the mirror 114, the mirrors 116a, 116b, the homogenizer 117, the partial transmission portion 118, and the projection lens 119 are fixed to the movable optical unit 132. Move with.

Next, the partially transparent portion 118 will be described with reference to FIG.
The partially transmitting portion 118 is composed of a plurality of rectangular transmission regions 118a and a non-transmissive or shielding region 118b having a low transmittance of the laser light that prevents the transmission of the laser light. The low transmittance is an energy density that does not contribute to crystallization on the irradiated surface when the transmitted beam is irradiated on the substrate described later. Therefore, the transmittance that is considered to be low transmission differs depending on the magnitude of the energy of the laser beam before transmission. In addition, the transmittance varies depending on the purpose of processing. The shielding region 118b can be arranged by forming a thin film of chromium or aluminum on a material having good transmission of laser light to reduce the transmission.

In the transmission region 118a, M pieces (integers of N or more) are arranged so as to have predetermined intervals in the X direction (scanning direction described later) and the Y direction (direction orthogonal to the scanning direction). The size of the transmission region 118a is set so that when the transmitted beam is applied to the substrate, the beam irradiation cross section has a length in the X direction of W and a length in the Y direction of L. In this example, each side of the transmission region 118a is along the X or Y direction. The length of the beam irradiation cross section is indicated by the length of the intensity flat region having a flat intensity, which is located inside the ambient intensity gradient region having an intensity gradient in which the intensity decreases toward the outside. The intensity flat region is shown, for example, as a region having an energy density of 96% or more of the maximum energy density.

In this embodiment, since the beam is set to be irradiated at the same magnification, the size of the beam on the irradiation surface of the object to be treated and the distance between the beams, and the size of the transmission region 118a and the distance between the transmission regions 118a. Is equal to the distance of. When the beam transmitted through the partially transmitted portion is not irradiated to the object to be processed at the same magnification, the size of the beam and the distance between the beams on the irradiated surface of the object to be processed satisfy the predetermined conditions in the present invention. The size of the transmission region 118a on the partially transparent portion 118 and the distance between the transmission regions 118a are set.
The transmission regions 118a are adjacent to each other and are displaced by a distance of 2 W-W / N in the X direction and L / N in the Y direction. Note that N is the number of times the beam is irradiated to the same location on the substrate (an integer of 2 or more), and can be arbitrarily set. The N number of times can be indicated by the number of times that the growth of the crystal grain size is saturated and the crystal grains become uniform when irradiated with the optimum energy density for crystallization. It can be said that even if the irradiation is usually performed more than N times, the effect is saturated in terms of crystallinity and the productivity is lowered. However, the numerical value of N can be appropriately set according to the purpose. According to the arrangement of the transmission regions 118a, on the substrate, M rectangular beams having a length W in the X direction and a length L in the Y direction are 2W-W / N in the X direction and L / N in the Y direction. Will be irradiated in the same direction in sequence.

Next, the operation of the laser annealing device 1 will be described.
The substrate 2 to be processed is placed on the substrate mounting table 120. For example, a substrate 2 on which an amorphous silicon film (not shown) is formed is used.
The erection unit 131 and the movable optical unit 132 are positioned at the initial positions. As a result, the initial irradiation position of the laser beam 101 irradiated through the movable optical unit 132 is determined.
For example, a triple wave YAG laser light having a repetition frequency of 6 kHz and a wavelength of 355 nm is output to the laser light source 100 as the laser light 101. In the present invention, a laser beam output from a continuously oscillating laser light source may be used as a pseudo pulsed light.

The pulsed laser beam 101 output from the laser light source 100 is reflected by the mirror 111 and the mirror 113. The laser beam 101 reflected by the mirror 113 is irradiated to the mirror 114 provided in the movable optical unit 132, reflected upward by the mirror 114, and sequentially reflected by the mirrors 116a and 116b in the movable optical unit 132 and downward. The laser beam 101 is directed toward the mirror, and the intensity distribution of the beam is made uniform by the homogenizer 117. The laser beam 101 that has passed through the homogenizer 117 irradiates the partially transmitted portion 118. As shown in FIG. 2, the beam 101a of the laser beam 101 at this time is irradiated on the partially transmitted portion 118. The cross section on the partial transmission portion 118 of the beam 101a has a size that covers the arranged M transmission regions 118a. Further, the partially transmitted portion 118 has a size that exceeds the cross-sectional shape of the irradiated beam 101a over the entire circumference.

The laser beam 101 is transmitted by the partially transmitting portion 118 according to the shape of each transmission region 118a, so that it is shaped into M beams 101b, and the substrate 2 is irradiated with the same magnification by the projection lens 119. FIG. 3 conceptually shows a state in which each beam 101b is irradiated on the substrate 2. The energy density on the irradiation surface is adjusted to, for example, 300 to 400 mJ / cm ² .
Since the transmission region 118a of the partial transmission portion 118 is projected at the same magnification in each beam 101b as described above, each beam 101b has M rectangular beams having a length W in the X direction and a length L in the Y direction. Is 2W-W / N in the X direction and L / N in the Y direction, and is sequentially displaced in the same direction.

During the above irradiation, the movable optical unit 132 is moved along the erection portion 131 at a predetermined speed, so that the irradiation position of the beam 101b on the substrate 2 moves in the X direction. That is, in this example, the moving direction of the movable optical unit 132 is the scanning direction of the laser beam 101, and while the movable optical unit 132 moves, the position change of the pulsed laser beam 101 irradiated at the repetition frequency is the laser beam. Corresponding to the feed pitch of 101, the beam 101b is irradiated to the same portion of the substrate 2 a plurality of times depending on the setting of the feed pitch.

When the movable optical unit 132 moves in the longitudinal direction of the erection portion 131, that is, in the X direction by a predetermined length (for example, the width of the substrate 2), the erection portion 131 is moved in the longitudinal direction of the optical system supports 130, 130, that is, in the Y direction. Move by a predetermined length. As a result, the irradiation position of the beam moves in the Y direction on the substrate 2 as shown in FIG. After moving in the Y direction, by moving the movable optical unit 132 in the X direction in the direction opposite to the above, the moving direction of the movable optical unit 132 becomes the scanning direction of the laser beam 101, and while the movable optical unit 132 is moving. The change in the position of the pulsed laser beam irradiated at the repetition frequency becomes the feed pitch of the laser beam, and the laser beam 101 is irradiated to the same portion of the substrate 2 multiple times.
By repeating the above operation, one surface of the substrate 2 can be annealed by laser light irradiation.

The laser beam 101 guided to the substrate 2 through the optical system 110 has an ambient intensity having an intensity gradient in the peripheral portion where the intensity decreases toward the outside, similar to the beam cross section shown in FIG. 6, due to the influence of diffraction or the like. It has a gradient area. Inside the ambient strength gradient region, there is a strength flat region where the strength is substantially flat. The ambient intensity gradient region may be 20 μm or less, which is smaller than the length of the thickened portion, and therefore the projection lens 119 does not need to have a high resolution. A low resolution (NA <0.05) projection lens can also be used, and the low resolution projection lens has a deep depth of focus, so the accuracy required for the entire device may be low, and the device is complicated. do not become.

In this embodiment, a plurality of intensity flat areas are arranged at predetermined intervals in the scanning direction and in the direction orthogonal to the scanning direction by arranging the transmission region 118a and the shielding region 118b in the partial transmission portion 118. The harmful effects of the ambient strength gradient range are eliminated.

Specifically, as shown in FIG. 4A, the rectangular (rectangular in this form) beam 101b is irradiated so as to be located in a row of M pieces. Each beam 101b has a cross-sectional shape on the substrate 2 along the scanning direction and the direction perpendicular to the scanning direction, and has a length W in the scanning direction and a length L in the direction orthogonal to the scanning direction in the intensity flat region. is doing.
For the M beams 101b, the number of irradiations per substrate is N times (N is an integer of 2 or more), and an interval of 2W-W / N in the scanning direction and L / N in the direction orthogonal to the scanning direction are set. Is located.

In the laser light irradiation step of irradiating the substrate 2 with the beam 101b, as shown in FIG. 4B, the substrate 2 is moved in the X direction with the movement amount (feed pitch) of the laser light 101 as W.
In the movement at this time, for example, scanning is performed so that the beam 101b is irradiated from the end portion in the X direction of the substrate 2 to the other end portion in the X direction.
As a result, as shown in FIG. 4B, the same spot on the substrate 2 is irradiated with a different beam 101b for each pitch, and the number of pitches becomes N times or more, so that the same spot on the substrate 2 is irradiated. N times of beam irradiation are performed. After scanning in the X direction is completed, a laser that moves the irradiation position of the beam 101b in a direction (Y direction or −Y direction) orthogonal to the X direction by a distance of (M + 1) × (L / N) at a relatively high speed. Carry out a light transfer process. The laser light moving step may be based on the irradiation position of the beam 101b at the time when the laser light irradiation step is completed, or after moving the irradiation position of the beam 101b in the X direction, the Y direction or −Y You may move in the direction. The movement in the X direction at this time may be one that returns to the initial position of irradiation of the beam 101b, or may be one that moves to an arbitrary position in the X direction.

After the irradiation position changing step, the irradiation step of irradiating the beam 101b while moving the substrate 2 in the X direction or the −X direction with the pitch amount W so that the beam 101b moves relatively with reference to the changed beam irradiation position. To carry out. This makes it possible to irradiate the same location with the beam 101b N times in other regions of the substrate 2.
By repeating these operations, the laser annealing process can be uniformly performed on the entire surface of the substrate 2.
By the above steps, it is desirable that the irradiation conditions are the same as those in the scanning direction without overlapping the intensity gradient regions not only in the X direction but also in the Y direction.

In the above embodiment, the laser light is simultaneously irradiated to the M transmission regions 118a, the laser light is scanned relative to the substrate 2 in the X direction, and the transmitted beam 101b is irradiated onto the substrate 2. After that, the irradiation position of the beam 101b is relatively moved in the Y direction with respect to the substrate 2 by a predetermined amount, and the beam 101b is further irradiated.
In the present invention, the beam irradiation of the M row may be similarly performed simultaneously at the position deviated by a predetermined amount in the Y direction with respect to the beam irradiation position of the M row, and an example thereof will be described below.

FIG. 5 shows a partially transmitted portion 1180 for irradiating the substrate 2 with the beam.
Similar to the above-mentioned partial transmission unit 180, the partial transmission region 1180 has M transmission regions 1180a arranged in a row, and each transmission region 1180a is such that when each of the transmitted beams irradiates the substrate 2. The position and size of each beam irradiation cross section are such that the length in the X direction is W and the length in the Y direction is L, and they are sequentially displaced in the same direction by 2W-W / N in the X direction and L / N in the Y direction. Is set. Also in this example, since the beam transmitted through the partially transmitted portion 1180 irradiates the substrate 2 at the same magnification, each transmission region 1180a has a length in the X direction of W and a length in the Y direction of L, and is 2W- in the X direction. They are sequentially displaced in the same direction by L / N in the W / N and Y directions.

Further, in this example, M transparent regions 1180a are set as one row, and a plurality of rows are arranged at intervals in the Y direction. In each row, when each transmitted beam irradiates the substrate 2, the rows of M beams are displaced from each other by a distance of (M + 1) × (L / N) in the Y direction or −Y direction. It is set to be irradiated. As described above, in this example, since the beam transmitted through the partially transmitted portion 1180 irradiates the substrate 2 at the same magnification, in the partially transmitted portion 1180, M rows of the transmission region 1180a are (M + 1) × each other. It is located at a distance of (L / N) in the Y direction or the −Y direction. In this example, M rows of transmission regions 1180a are provided in the partial transmission portion 1180 in n rows (n is an integer of 2 or more). The region other than the transmission region 1180a of the partial transmission portion 1180 is a shielding region 1180b, and the transmission region 1180a and the shielding region 1180b have the same transmission and shielding of laser light as the transmission region 118a and the shielding region 118b described above. It can be configured to do so.

When irradiating the substrate 2 with a beam, the laser beam 101 is divided and irradiated with the beam 101c corresponding to each row so as to cover the transmission region 1180a of each row, whereby M × n pieces on the substrate 2 are irradiated. Can irradiate the beam of. By irradiating this beam while scanning relative to the substrate 2, a wide area of the substrate 2 can be processed at one time. The laser beam 101 may irradiate the substrate 2 with M × n beams by irradiating the substrate 2 with beams having a size of covering n rows of transmission regions 1180a with M rows of laser light 101 without division. .. Further, after irradiating the substrate 2 with M rows of M beams while relatively scanning n rows of beams, the irradiation position of the n rows of beams with M rows is set in the Y direction or −Y direction (M + 1) × (L /). N) The position may be changed in the Y direction by a distance of × n, and then the substrate 2 may be processed by scanning while irradiating the beams of n rows with M rows.

In each of the above embodiments, the laser light irradiation using one laser light source has been described, but a row of M beams is formed by the laser light output from each laser light source using a plurality of laser light sources. It can also be created and irradiated to the substrate.
In this case, the irradiation position by each laser light source is set so that a row of M rectangular beams can be arranged on the substrate. That is, in the row of M beams, the length in the X direction, which is the scanning direction, is W, the length in the Y direction, which is the direction orthogonal to the scanning direction, is L in the beam irradiation cross section, and each side of the beam is X. It is along the direction and the Y direction. Further, the beams are set to be adjacent to each other and to be displaced by a distance of 2 W-W / N in the X direction and a distance of L / N in the Y direction. In addition, N is the number of times that the beam is irradiated to the same place on the substrate.
Further, the M rows of each laser light source are set so that the adjacent rows are displaced by (M + 1) × (L / N) in the Y direction as shown in FIG. 5 in the direction orthogonal to the scanning direction. ..
This makes it possible to process the substrate in a wide area at once using n laser light sources.
After that, the irradiation position is changed so that the irradiation position of the beam obtained by each laser light source deviates from the substrate by (M + 1) × (L / N) × n in the Y direction, and the scanning and irradiation of the beam are repeated.

Specific examples of the present invention will be described below.
(Example 1)
Using the laser annealing device shown in FIG. 1, a laser beam with a wavelength of 355 nm, a pulse energy of 7.5 mJ, and a repetition frequency of 6 kHz emitted from a triple-wave YAG laser light source was used to irradiate amorphous silicon with a beam 10 times at the same location. It was irradiated so as to be (N times).
The laser beam is incident on a homogenizer composed of a cylindrical lens, and a beam having a flat intensity distribution with a beam size of 8 mm × 0.25 mm is shaped as shown as beam 101a in FIG. 2A on a partially transmitted portion. did. As the mask, a mask base material having a chrome film formed is used, and the mask is not coated with a chrome film having a size of 0.2 mm × 0.2 mm (corresponding to W × L of the present invention). The openings are sequentially displaced by 0.38 mm (2W-W / N) in the long direction of the substrate and 0.02 mm (L / N) in the short direction of the substrate, and periodically 20 (books). (Corresponding to M of the invention) was provided. The mask corresponds to the partially transmissive portion of the present invention, and the opening corresponds to the transmissive region.
Amorphous silicon formed on a glass substrate with a projection lens that periodically generates 20 beams with a size of 0.2 mm × 0.2 mm and projects the obtained beams at the same magnification with the above mask. The membrane was irradiated. The energy density at this time was 340 mJ / cm ² (= 7.5 / (0.8 × 0.025) -loss).

When irradiating the beam, the beam was scanned in the long direction (X direction) of FIG. 2 at a speed of 0.2 mm × 6 k = 1.2 m / sec. This makes it possible to irradiate amorphous silicon with a beam at a pitch of 0.2 mm.
A glass substrate consisting of 2200 mm × 2400 mm is fixed, a homogenizer, a mask, and a projection lens are arranged in a movable optical system unit, and the beam is emitted with a linear motor stage (not shown) at a speed of V = 1.2 mm / sec. Moved from end to end parallel to the sides of the substrate. After moving to the edge of the substrate, it moves in the direction orthogonal to the moving direction (20 + 1) × 0.2 mm / 10 = 0.42 mm (corresponding to (M + 1) × (L / N)), and at the above 1.2 m / sec. Irradiation was repeated. Since the movement of 0.42 mm is in the direction of the width of the glass substrate of 2200 mm, the movement and irradiation were repeated 5238 times.

(2) Example 2
Ten laser light sources that output laser light with a pulse energy of 7.5 mJ and a repetition frequency of 6 kHz are used, and 20 of the above-mentioned 0.2 mm × 0.2 mm beams are periodically arranged for each laser light source, and the laser light source is used. The beam rows were set to be adjacent to each other and offset by 0.42 mm in the direction orthogonal to the scanning direction. A plurality of rows of the beams were scanned against a glass substrate having a glass size of G8.5 (Y: 2200 mm × X: 2500 mm) in the 2200 mm direction at 1.2 m / sec in the same manner as described above. Then, the beam was moved by 0.42 mm × 10 (corresponding to n) = 4.2 mm, and the irradiation at 1.2 m / sec was repeated. Since the movement of 4.2 mm is in the direction of the width of the glass substrate of 2200 mm, the movement and irradiation were repeated 523 times.

Although the present invention has been described above based on the above-described embodiments and examples, the present invention is not limited to the contents described in the above-described embodiments and examples, and does not deviate from the scope of the present invention. As long as it is possible, the above-described embodiments and examples can be appropriately modified.

1 Laser annealing device 2 Substrate 3 Beam cross section 100 Laser light source 101 Laser light 101a Beam 101b Beam 101c Beam 110 Optical system 111 Mirror 113 Mirror 114 Mirror 116a Mirror 116b Mirror 117 Homogenizer 118 Partial transmission part 118a Transmission area 1180 Partial transmission part 1180a Transmission area 119 Projection lens 120 Board mount 130 Optical system support 131 Elevation 132 Movable optical unit

Claims (12)

The beam cross section on the irradiation surface of the object to be treated has an ambient intensity gradient region having an intensity gradient in which the intensity decreases toward the outside, and an intensity flat region having a flat intensity inside the ambient intensity gradient region. A beam of pulsed laser light is positioned at M points (M is an integer of 2 or more) on the object to be processed, and the beam is irradiated to the object to be processed while being relatively scanned. It has an irradiation step of irradiating the same portion of the processed body with the beam N times (N is an integer of 2 or more).
The beam is adjacent to the beam in the beam cross section on the irradiation surface, where W is the length of the intensity flat region in the scanning direction and L is the length of the intensity flat region in the orthogonal direction orthogonal to the scanning direction. Sequentially located at a distance of 2 W-W / N in the scanning direction and L / N in the direction orthogonal to the scanning direction, and the feed pitch per beam irradiation in the scanning direction is W. A laser annealing method characterized by. After the irradiation step, an irradiation position changing step of changing the relative irradiation position of the M point of the beam with respect to the object to be processed by a distance of (M + 1) × (L / N) in a direction orthogonal to the scanning direction is performed. The laser annealing method according to claim 1, wherein the irradiation step is executed according to the changed irradiation position, and these irradiation steps and the irradiation position change steps are alternately repeated. In the irradiation step, a plurality of beams located at the M points are set as one set of beam groups, the beam groups are set as a plurality of sets, and adjacent sets of beam groups are arranged in a direction orthogonal to the scanning direction (M + 1) ×. Claim 1 is characterized in that the beams in each beam group are positioned at intervals of (L / N) so as to irradiate the object to be processed at the same time while scanning the beam in each beam group relative to the object to be processed. The laser annealing method described. A plurality of laser light sources for locating the pulsed laser beam at each of the M points (M is an integer of 2 or more) on the object to be processed are prepared, and the beam from each laser light source is generated for each laser light source. The beam rows at the M locations by each laser light source are positioned at the M locations, with an interval of (M + 1) × (L / N) in the direction orthogonal to the scanning direction in the adjacent beam rows. The laser annealing method according to any one of claims 1 to 3, wherein the laser annealing method is characterized. The laser annealing method according to any one of claims 1 to 4, wherein the beam has a rectangular shape in the cross-sectional shape of the beam on the irradiation surface. The laser annealing method according to claim 5, wherein each side of the beam is along a scanning direction or a direction orthogonal to the scanning direction. The laser annealing method according to any one of claims 1 to 6, wherein the object to be treated is an amorphous silicon film. The beam cross section on the irradiation surface of the object to be treated has an ambient intensity gradient region having an intensity gradient in which the intensity decreases toward the outside, and an intensity flat region having a flat intensity inside the ambient intensity gradient region. A laser annealing device that irradiates the object to be processed with a beam of pulsed laser light.
A laser light source that outputs the laser beam and
It has an optical system that shapes the laser beam and guides the shaped beam of the laser beam to the object to be processed to irradiate the object to be processed.
The optical system has a plurality of beams on the object to be processed, in which the length in the scanning direction in the intensity flat region is W and the length in the direction orthogonal to the scanning direction is L, and the beams are in the scanning direction. 2W-W / N, and has a partially transmissive portion for positioning M (M is an integer of 2 or more) at intervals of L / N in a direction orthogonal to the scanning direction.
Further, it has a moving device that moves the beam irradiated to the object to be processed relative to the object to be processed.
The moving device is a laser annealing device having a mechanism for performing the relative movement so that the feed pitch per irradiation of the beam in the scanning direction is W. The laser light source repeatedly outputs the laser beam at a frequency of RHz.
The laser annealing device according to claim 8, wherein the moving device has a speed V in the scanning direction satisfying V = W × R. 8. The moving device is characterized by having a mechanism for changing the relative position of the beam with respect to the object to be processed by a distance of (M + 1) × (L / N) in a direction orthogonal to the scanning direction. Or the laser annealing apparatus according to 9. The beam cross section on the irradiation surface of the object to be treated has an ambient intensity gradient region having an intensity gradient in which the intensity decreases toward the outside, and an intensity flat region having a flat intensity inside the ambient intensity gradient region. A laser annealing device that irradiates the object to be processed with a beam of pulsed laser light.
A plurality of laser light sources that output the laser light, respectively, and
It has an optical system that shapes each laser beam and guides the shaped beam of the laser beam to the object to be processed to irradiate the object to be processed.
The optical system has a beam having a length in the scanning direction of W and a length in the direction orthogonal to the scanning direction L on the object to be processed for each laser light source, and the beam is the scanning. It has a partially transparent portion for arranging M rows (M is an integer of 2 or more) at intervals of 2 W-W / N in the direction and L / N in the direction orthogonal to the scanning direction.
In the partially transmitted portion, the array of M adjacent beams corresponding to each laser light source is displaced by a distance of (M + 1) × (L / N) in a direction orthogonal to the scanning direction, and the object to be processed is processed. It is set to be located on top and
Further, a laser annealing device comprising a moving device for moving the beam irradiated to the object to be processed relative to the object to be processed. Assuming that the number of the plurality of laser light sources is n, the moving device moves the beam relative to the object to be processed at a distance of (M + 1) × (L / N) × n in a direction orthogonal to the scanning direction. The laser annealing apparatus according to claim 11, further comprising a mechanism for changing the above.

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