JP2009534820A - Large substrate laser annealing apparatus and large substrate laser annealing method - Google Patents

Abstract

  The present invention relates to an apparatus for laser annealing of a large substrate including an optical device for producing a thin irradiation line (31) on an irradiation surface (36) of a substrate (32), wherein the irradiation line (31) is produced from a laser beam. The scanning device has a cross section with a spread in one direction and a spread in the second direction, the spread in the first direction being a multiple of the spread in the second direction, and the scanning device defines the first section of the irradiated surface of the substrate. It is configured to scan in the second direction with the irradiation line. According to the invention, the apparatus comprises a rotating device for rotating the substrate (32) 180 ° around the axis of rotation (38) relative to the irradiation line (31) after scanning the first section (37), The axis of rotation is perpendicular to the illumination surface (36), and the scanning device moves the second section of the illumination surface (36) of the substrate (32) adjacent to the first section of the illumination surface (36) of the substrate (32), The irradiation line (31) is configured to scan in the second direction (y).

Description

Cross-reference to related applications According to 35 USC 119 (e) No. 1, this application claims priority to provisional application 60 / 745,333 filed April 21, 2006.

  The present invention relates to a laser annealing apparatus for a large substrate. The invention further relates to a method for laser annealing of large substrates.

  The conversion of a-Si to p-Si is performed by a heat treatment at about 1000 ° C. This process is used only for a-Si on a heat resistant substrate such as quartz. Such a material is more expensive than ordinary float glass used for video applications.

  The light beam, or in particular the laser beam that induces crystallization of a-Si, can form p-Si from a-Si without destroying the substrate due to thermal loads during crystallization.

Amorphous silicon is deposited on a substrate such as glass, quartz or synthetic fiber by a low cost process such as sputtering or chemical vapor deposition (CVD). As laser-induced subsequent crystallization processes, excimer laser crystallization (ELC), sequential lateral crystal growth (SLS) or fine beam crystallization (TDX ™) are well known. An overview of these various manufacturing processes is shown by, for example, the following non-patent documents. Polycrystalline silicon produced by any one of these methods is called low temperature polycrystalline silicon (LTPS).
In SID 00 Digest, 1-3. S. “Thin Beam Crystallization Method: A New Laser Annealing Tool with Lower Cost and Higher Yield for LTPS Panels” by Knowles et al. “P-60: Thin Laser Beam Crystallization method for SOP and OLED application” by Ji-Yong Park et al. In SID 05 Digest, 1-3. “LCD Panel Manufacturing Moves to the Next Level-Thin-Beam Directional X'talization (TDX) Improve Yield Yield, TCZ GmbHH Company Booklet

  Most of the laser crystallization processes described above have in common that the focused laser beam is scanned over the substrate by moving the stage on which the substrate is mounted and / or by moving the laser beam.

For example, a line beam having a typical size of 0.5 mm × 300 mm and having a homogeneous intensity distribution is used for silicon annealing of large substrates using, for example, excimer laser crystallization (ELC). State-of-the-art optical systems use refractive optical illumination systems that include crossed cylindrical lens arrays to form the desired intensity distribution. These arrays are described in terms of function, for example in US 2003/0202251 (A1), but with a suitably shaped sub-aperture, the homogenization splits the incident light into multiple light beams. It is an example of a more general group of schemes. By superimposing these many rays on the focal plane, the difference in intensity is averaged and the rays are homogenized. The line beam scans the substrate in the minor axis direction, that is, the width direction, that is, the direction in which the spread of the light beam is small.
US Patent Application Publication No. 2003/0202251 (A1)

The future trend is to reduce the width, that is, the short axis, as much as possible, and to increase the length, that is, the long axis, of the line beam used for crystallization of the amorphous silicon film. Thus, US 2006/0209310 (A1), which is incorporated herein by reference, has dimensions of 5-15 μm × 700 mm or more (eg, 5 μm) for the crystallization process. X730 mm), and discloses a long and thin light beam that scans the substrate surface in the minor axis direction. Such an elongated irradiation line having a homogeneous or at least a defined intensity distribution is formed from a light beam emitted from an excimer laser by a specific homogenization scheme, after which the projection / reduction lens has its homogenized light beam at the irradiation surface. Is projected / reduced.
US Patent Application Publication No. 2006/0209310 (A1)

In order to increase throughput, a future trend is to use larger substrates. Particularly in the “thin beam crystallization” (TDX) process, where a thin and long line beam is used, increasing the length leads to various problems.
-Larger mirrors or lenses are required to increase dimensions. The dimensions are limited by the length of the machine used to manufacture the lenses and mirrors and the coating technique.
-To increase the length, more effective gearing is required. The required transmission is proportional to the length of the beam.

  Accordingly, it is an object of the present invention to provide an alternative solution for an apparatus and method for processing larger substrates, particularly substrates that exceed the dimensions used so far.

  According to a first aspect, the present invention relates to an apparatus for laser annealing of a large substrate, including an optical device and a scanning device for producing a thin irradiation line on the irradiation surface of the substrate. This irradiation line is produced from a laser beam and has a cross section with a spread in the first direction and a spread in the second direction, and the spread in the first direction is a multiple of the spread in the second direction. The scanning device is configured to scan the first section of the irradiation surface of the substrate with the irradiation line in the second direction. As a main idea, the apparatus includes a rotating device that rotates the substrate 180 ° around the rotation axis with respect to the irradiation line after scanning the first section, the rotation axis being perpendicular to the irradiation surface. Furthermore, the scanning device is configured to scan the second section of the irradiation surface of the substrate adjacent to the first section of the irradiation surface of the substrate with the irradiation line in the second direction.

  Preferably, the laser annealing device further includes an adjusting device for adjusting the spread of the irradiation line in the first direction to a predetermined length. In particular, the adjusting device means a device capable of variously limiting the spread of the irradiation line during the laser annealing or laser crystallization treatment process, or at least before or after. The advantage of such an adjusting device is that a region to be processed in the annealing process can be defined in advance.

  The adjusting device includes, for example, at least one blade that cuts the irradiation line in the first direction on at least one side of the irradiation line. If one edge of the region to be processed and the outer edge of the substrate to be processed are already well defined with respect to one another, one blade will suffice. This may be because, for example, these edges are made in the factory and pre-adjusted, or one edge of the irradiation line and one edge of the substrate are pre-positioned relative to each other, for example by a movable stage or a movable optical device on which the substrate rests. This is the case.

  As an alternative to or in addition to one or more blades, the adjustment device may include zoom optics that reduces the spread of the radiation in the first direction. The advantage of the zoom optical system is that the laser output can be reduced and the life of the entire system can be extended.

  In a preferred embodiment, the rotating device includes a rotating table on which a substrate is placed. The platform is used to position the substrate in the first and second directions with respect to the radiation already described above. The platform is therefore preferably linearly movable. Further, the platform may be rotatable so that it can meander scan over the substrate with an irradiation line.

According to a second aspect, the invention relates to a corresponding method. The corresponding method of laser annealing of large substrates according to the present invention is:
-A thin irradiation line is produced on the irradiation surface of the substrate from the laser beam, and the irradiation line has a cross section extending in the first direction and extending in the second direction, and the extension in the first direction is the second direction. A process that is a multiple of the spread to
Scanning the first section of the irradiated surface of the substrate in the second direction with the irradiation line;
-Rotating the substrate 180 ° around the axis of rotation with respect to the irradiation line, the axis of rotation being perpendicular to the irradiation surface;
Scanning a second section of the substrate irradiation surface adjacent to the first section of the substrate irradiation surface in a second direction with the irradiation line;

  If the beam profile in the second direction is different with respect to the rising and falling edges, it is important to rotate the platform 180 degrees. To obtain similar annealing / crystallization quality results in both sections of subsequently processed substrates, the scanning direction should be the same in successive processing steps.

  Preferably, the spread of the irradiation line is adjusted to a predetermined length in the first direction before and / or during the scanning of the first section. The region to be processed in the first annealing step is thus predefined.

  Further, preferably, the spread of the irradiation line is adjusted to a predetermined length in the first direction after scanning the first section but before and / or during the operation of the second section. The region to be processed in the second annealing step is thus predefined.

  With respect to the spread of the irradiation line, it is advantageous if the gap between the first section and the second section or the overlap between the first section and the second section is adjusted to a predetermined value. The seams that inherently result from two successive processing steps, ie, an annealing step of the first section of the substrate and an annealing step of the second section of the substrate, may be defined to some extent.

  According to a third aspect, the present invention relates to an apparatus for laser annealing of a large substrate, including two optical devices that produce thin irradiation lines on the irradiation surface. Both radiations are produced from the respective laser beam or from only one laser beam. Both irradiation lines have a cross section extending in the first direction and extending in the second direction, and the extension in the first direction is a multiple of the extension in the second direction. The apparatus is further configured to scan the first section of the irradiation surface of the substrate in the second direction with one of the irradiation lines, and scan the second section of the irradiation surface of the substrate with the other irradiation line in the second direction. Includes a scanning device. The above-described optical device according to the present invention and the other optical devices described above according to the present invention form an irradiation line in which the thin irradiation lines described above and the other thin irradiation lines described above are continuous on the irradiation surface of the substrate. It is configured to

  In a preferred embodiment, the optical device described above and the other optical devices described above are such that the continuous radiation does not vary with a constant intensity along the first direction and a position along the first direction. It is comprised so that it may become a straight line which has intensity distribution. This configuration allows annealing and crystallization of, for example, a silicon film on a large substrate without having incomplete crystallization seams that occur in one annealing step and when other bonding methods are used.

  In another preferred embodiment, the optical device described and / or the other optical device described is a long axis that limits the expansion in the first direction of the irradiation line described above and / or another irradiation device described above. Includes expansion limiter. This solution is advantageous when producing a well-defined irradiation line, particularly when producing a continuous irradiation line having a predetermined intensity distribution in the first major axis direction.

  Similar to the embodiments described with respect to the first aspect of the invention, the restriction device may include one or more cutting blades.

  It is preferable that the broadening of the irradiation axis in the major axis direction is not just manufactured and adjusted in advance at the factory. Depending on the application method, adjustments may be required during processing or in particular between two processing steps. Accordingly, the described optical device and / or the other optical device described are adjusted to adjust the aforementioned irradiation line and / or the other irradiation line described above and / or the resultant irradiation line in the first direction. An apparatus may be included.

  The adjustment device may include, for example, a movable cutting blade and / or zoom optics.

  As already mentioned above, it is advantageous if the sum of the irradiation lines produces a linear ray with preferably a homogeneous intensity and a second direction intensity distribution along the long axis. This requires that the edges of the radiation being joined are well defined and have a known intensity gradient. The described optical device and / or the other optical device described above produces a light beam in which the described irradiation beam is slightly out of focus with respect to the irradiation surface of the substrate, and / or the other irradiation beam described above. Can be created to produce other rays that are slightly out of focus on the illuminated surface, it is possible to create a well-defined constant intensity gradient.

According to a fourth aspect, the invention relates to a separate method for laser annealing of large substrates, the method comprising:
-A thin irradiation line is produced on the irradiation surface of the substrate from the laser beam, and the irradiation line has a cross section extending in the first direction and extending in the second direction, and the extension in the first direction is the second direction. A process that is a multiple of the spread to
Scanning the first section of the irradiated surface of the substrate in the second direction with the irradiation line;
-Another thin irradiation line is produced on the irradiation surface of the substrate, the irradiation line being produced from the laser beam, having a cross section extending in the first direction and extending in the second direction, A process in which the spread is a multiple of the spread in the second direction;
To form a continuous, preferably straight beam on the illuminated surface of the substrate and preferably have a homogeneous intensity (and a predetermined, particularly homogeneous second direction intensity distribution) along the first direction, Joining the thin irradiation line described above and the other thin irradiation lines described above.

  In order to define the treatment area and the long-axis intensity distribution during manufacturing, the spread of the described irradiation lines and the other irradiation lines described above is limited or adjusted in the first direction.

In order to create a well-defined long-axis intensity gradient, the described irradiation line and / or other described irradiation lines may be slightly out of focus on the irradiation surface. Preferably, with regard to defocusing, the above-described irradiation line and / or the above-described other irradiation lines have a certain gradient at each edge in the major axis direction. A typical value of the distance between the irradiation surface and the most preferable focal position is 2 to 3 times λ / NA ² , where NA represents the numerical aperture of the long axis of the light beam and λ represents the wavelength.

  According to a fifth aspect, the present invention relates to an apparatus for laser annealing of a large substrate having an optical device that produces a thin irradiation line on the irradiation surface of the substrate, wherein the irradiation line is generated from a laser beam and is directed in a first direction. A cross-section having a spread and a spread in the second direction, the spread in the first direction being larger by a multiple of the spread in the second direction, and the scanning device illuminating the first section of the illuminated surface of the substrate The line is configured to scan in the second direction. In a first alternative embodiment, the optical device includes at least two optical elements having refractive power to produce an irradiation line on the irradiation surface, the optical element being an integral part of the projection / reduction lens. The at least two optical elements are configured to be adjacent to each other in the first direction. A second alternative embodiment includes another optical device that produces another thin illumination line on the illuminated surface of the substrate, the illumination line being produced from the laser beam and extending in the first direction and in the second direction. The spread in the first direction is a multiple of the spread in the second direction. The optical device includes at least one optical element having refractive power, which is an integral part of the projection / reduction lens, for producing an irradiation line on the irradiation surface. In order to produce other radiation on the illumination surface, the other optical device includes at least one other optical element having refractive power, which is an integral part of the projection / reduction lens. The at least one optical element and the at least one other optical element are configured to be adjacent to each other in the first direction.

  The plurality of optical elements described above and / or the one optical element described above and the other optical elements described above may be lenses or mirrors.

  The plurality of optical elements described above and / or the one optical element described above and the other optical elements described above are preferably the latest optical elements having a refractive power used in the projection / reduction optical system. The protective window between the projection / reduction optical system and the substrate is not meant by the expression “reflective optical element”, but merely as an optical element involved in such irradiation / reduction operations. Is only meaningful.

  According to a sixth aspect, the present invention relates to another apparatus for laser annealing of a large substrate including an optical device that produces a thin irradiation line on the irradiation surface of the substrate, wherein the irradiation line is generated from a laser beam and travels in a first direction. And a cross section extending in the second direction, the extension in the first direction being larger by a multiple of the extension in the second direction, and the scanning device is configured to irradiate the first section of the irradiation surface of the substrate with the irradiation line It is configured to scan in the second direction. According to the present invention, in order to produce an irradiation line on the irradiation surface, the optical device includes one of the latest optical elements having refractive power, which is an integral part of the projection / reduction lens. In order to increase the length of the irradiation line produced by the optical device, the distance between the modern optical element and the irradiation surface of the substrate is selected to be longer than 500 mm.

  The distance between the latest optical element and the irradiation surface of the substrate may be greater than 600 mm. Preferably, the distance is greater than 700 mm, more preferably greater than 800 mm, even more preferably greater than 900 mm, and most preferably greater than 1000 mm.

  Alternatively or additionally, the optical device may include a longitudinal beam expander that expands the laser beam in the first direction at a divergence angle to the spread of the irradiation beam in the first direction, where the divergence angle is Greater than 7 °.

  The divergence angle can also be greater than 15 °. Preferably, the divergence angle is greater than 20 °, more preferably greater than 25 °, even more preferably greater than 30 °, and most preferably greater than 35 °.

  Many of the solutions described result in seams on the substrate. This seam is due to the discontinuity due to the joining of two mirrors or lenses or the two-step process technique. Generally, the seam is not a problem because the substrate is eventually cut. However, depending on the preferred panel dimensions, the cutting line will be at the center of the substrate or off the center. It is therefore possible to move the seam position in all the solutions described.

  Examples are shown in the drawings and are described in more detail below with reference to the drawings. Identical or functionally similar components are identified by the same reference number.

  In the following description, the major axis is an axis perpendicular to the scanning direction. The short axis is an axis parallel to the scanning direction.

  For simplicity, all optical elements shown are lenses. In general, it is advantageous if the optical element that focuses the light beam in the minor axis direction and the optical element that irradiates the field defining component onto the substrate are mirrors. As described in the pamphlet of International Publication No. 2006/066687 A1, when a cylindrical mirror is used instead of a cylindrical lens, a so-called bow tie error can be prevented.

First Preferred Embodiment: Rotation of Stand A first preferred embodiment according to the present invention will be described with reference to FIGS. The apparatus for laser annealing of large substrates according to the first preferred embodiment includes an optical device that produces a known type of thin radiation. An example of such an optical device is disclosed in, for example, US Patent Application Publication No. 2006 / 0209310A1. An alternative optical device is disclosed in US Pat. No. 5,721,416A. The apparatus further includes a table on which the substrate is placed. The stage may move in a linear direction so that the irradiation line scans the substrate surface. Furthermore, the platform may rotate around a rotation axis perpendicular to the substrate surface.

  FIG. 1 shows a schematic view of the apparatus as viewed from above. The drawing shows the surface 36 of the substrate 32 and the radiation 31 produced by the optical device described above. The substrate 32 is rectangular and has a length l and a width w. The length direction is parallel to the y direction of the Cartesian coordinate system, and the width direction is parallel to the x direction. The substrate is, for example, a conventional float glass covered with a thin amorphous silicon layer having a thickness of 50 nm.

The irradiation line 31 is mainly rectangular in the xy-plane and extends in the orthogonal x and y directions of the Cartesian coordinate system. y-direction extent is indicated by reference numeral A _s, x-direction extent is indicated by reference numeral A _l. Spread _{A s} of the short axis direction is, for example, about 5 to 7 .mu.m, spread _{A l} in the long axis direction is 730mm, for example. In the long axis _Al direction x, the irradiation line 31 is homogeneous, that is, the intensity is made as constant as possible. In the short axis A _s direction y, in the strength distribution constant, even as large as possible a gradient of the intensity at the edge (top hat distribution). Instead of a constant top hat distribution in the y direction, the irradiation line 31 rises relative to an intensity distribution similar to that shown in FIG. 36 of US 2006/0209310 A1, ie, a falling edge T. The edge L may have a distribution with a smaller gradient. Both the rising edge L and the falling edge T of the irradiation line 31 shown in FIG. 1 are indicated by respective reference numerals. The reference numerals used in FIG. 1 of the present application correspond to the respective reference numerals in FIG. 36 of US Patent Application Publication No. 2006 / 0209310A1.

The idea of the present invention is to use a laser line 31 shorter than the width w of the substrate 32. The substrate 32 must be processed in two steps as shown in FIGS.
- the dimensions of the longitudinal direction A _l of thin laser beam 31 is cut into desired dimensions by the blade. In order to adjust the dimension of the light beam 31, a zoom optical system can be used instead of using a blade. The advantage of the zoom optical system is that the laser output can be reduced and the lifetime of the entire system can be extended.
The substrate 32 is only processed on one side in the first step. For this purpose, the irradiation line 31 scans the first section of the surface 36 of the substrate 32 and the stage moves linearly in the scanning direction 35 so that the silicon crystallizes in that section. FIG. 2 shows the substrate 32 and the irradiation line 31 after this processing step. The crystallized section of substrate 32 is designated by reference numeral 37 in FIG. 2 and the uncrystallized section is designated by reference numeral 36.
-The platform rotates 180 ° around the axis 38 of the rotation 39 (Fig. 3) and returns to the initial position (Fig. 4). In the minor axis direction A _s, when the distribution of light rays 31 and 33 are different in the falling edge T and the rising edge L as described above, it is important. In order to obtain similar process results, the scanning direction of this process should be the same in both processes.
The size of the narrow laser beam 33 has to be readjusted by means of a blade or a zoom lens, for example as already mentioned above. The substrate 32 is processed on the other side in the second step. For this purpose, the irradiation line 33 scans the second section of the surface 36 of the substrate 32 adjacent to the first section, and the stage moves linearly in the scanning direction 35 so that the silicon crystallizes in the second section. To do. FIG. 5 shows the substrate 32 and the irradiation line 33 after this processing step. The crystallized section of substrate 32 is indicated by reference numeral 37. A seam 34 results at the edge of the laser beam 33 in the longitudinal direction A ₁ adjacent to the previously crystallized section 37. This is because the energy density at the edge of the light beam 33 has decreased. If the beam cutting blade is close to the substrate 32 and thus the resulting gradient of energy density is small, the seam 34 will be very small.

As already described, a seam is formed at the boundary of the processing area. The position of the seam can be moved according to the adjustment of the dimension of the laser beam in the long axis _Al direction x.

  The disadvantage of this solution is that the process requires two steps and that a turntable needs to be implemented. On the other hand, the turntable can be used very flexibly. For example, rotating the stage 90 ° affects the orientation of the Si crystal and defines the preferred orientation for other electronic components on the substrate.

  Some substrates have a chemical structure in either the scanning direction or the direction perpendicular to the scanning direction, so tilting the table to a slight degree can prevent the chemical structure from appearing after processing.

  An advantage of the first preferred embodiment of the present invention is that the current system for fourth generation size panels (730 mm × 920 mm) can be upgraded to the fifth generation size 1100 mm × 1300 mm. Furthermore, the conduction devices required for the system are the same.

Second Preferred Embodiment: Another possibility to extend the length of the laser beam of the lens or / and mirror junction substrate is to include at least one lens of the mirror of the optical device that produces a thin illumination line on the illuminated surface of the substrate. It is to join. In particular, the lens (mirror) that is closest to the substrate has to spread greatly in the long axis direction.

  FIGS. 6 and 7 show the main principle of an optical device that can produce thin radiation. FIG. 6 is a plan view of an optical device according to the prior art viewed in the xz-plane. FIG. 7 is a plan view of the same optical element viewed in the yz-plane. The optical device includes two sets of cylindrical lens arrays 1a and 1b, and constitutes a two-stage fly-eye type homogenizer and a convex cylindrical condenser lens 3 that are optically activated in the x direction. The optical device further includes a thin cylindrical lens 2 composed of a plurality (three in this case) of cylindrical lens pieces 2a, 2b, 2c, a cylindrical lens 4 and a projection element, that is, a reduction optical system, particularly in the examples shown in FIGS. Includes a cylindrical lens 5 optically activated in the y direction.

The homogenizer in the long axis _Al direction x is constituted by two sets of cylindrical lens arrays 1a and 1b. 1a and 1b include a plurality of cylindrical small lenses 1aa, 1ab and 1ac and 1ba, 1bb and 1bc, respectively. is constructed adjacent to each other, each having a focal length _{f 1,} resulting in an array 1a, the focal length is _{f array} next 1b configuration, the focal length of the condensing cylindrical lens 3 becomes _{f 3.} The incident laser beam 10 propagating in the z direction is divided into a plurality of small beams corresponding to the number of small cylindrical lenses 1aa, 1ab, 1ac of the first cylindrical lens array 1a. Each small light beam is focused at a distance of the focal distance f _array and forms a divergent light beam when it hits the condenser lens 3. The condenser lens 3 changes the angular distribution of small rays into an image plane distribution on a plane 6 on which the substrate is positioned. The dimensions of the image plane based on the focal length f ₃ of the lens 3, the maximum angle of the angular distribution of the rays is determined by the array 1a, 1b.

Homogenization scheme of the short axis _{A s} is the concept of thin lens 2 which have already been described in U.S. Patent Application Publication No. 2006 / 0209310A1 Pat. Individual cylindrical lenslets 2a having a curvature in the short axis _{A s} direction y, 2b, 2c is moved independently of the short axis _{A s} direction direction y. The principal ray 10a of the short axis A _s direction y is polarized in accordance with the moving amount. The dimensions of the major axis _{A l} direction of the small lenses 2a, 2b, 2c are cylindrical lens elements of the lens array 1a 1aa, 1ab, it is equivalent to one dimension of 1ac. Cylindrical lens element 4 focal plane, i.e. in the focal length f ₄ to the cylindrical lens 4, the width of the beam is based on the divergence of the incident light short axis As direction y. Since some of these small rays that have moved relative to each other overlap, it is possible to create a homogenized ray profile in the minor axis As direction y. A field defining element 7, for example a field stop, can be positioned at the position of the focused light beam in the short axis As direction y. The projection optical system 5 projects the field defining element 7 on the plane of the substrate 6. The projection optical system 5 in this example is a cylindrical lens (which can be replaced by a mirror) that does not affect the propagation of the light beam in the long axis _Al direction x. The projection optical system 5 may reduce the spread of the light beam in the short axis As direction y.

As seen in FIG. 6, the optical element 5 is wider at the long axis A _l direction x. The following solution describes how a larger field size can be achieved with a limited size optical element 5 (in the long axis _Al direction x).

One solution to achieve a larger field size is to use two independent optical devices of the type described above and join them together. FIG. 8 shows two devices identical to those shown in FIGS. 6 and 7 joined in the long axis _Al direction x. In particular, the cylindrical lens 5 are configured adjacent to each other in the longitudinal A _l direction x. The gap 5g between the two cylindrical lenses 5 is predetermined so that the gradients of the edges on at least the adjacent sides of the irradiation lines 6a and 6b formed on the surface of the substrate, that is, the irradiation surface 6, are at least partially overlapped. Has been.

  The gap 5g between the two adjacent cylindrical lenses 5 is further reduced, and particularly when the gap 5g is reduced to essentially zero, an overlapping region 9 of the irradiation lines 6a and 6b is generated, and as a result, Strength increases. With the cutting blades 8a, 8b, 8c, 8d constructed near the irradiation plane 6, the overlap can be adjusted as shown in FIG. The adjustment width of the cutting blade 8 is shown in FIG. 8 using arrows 28a, 28b, 28c, and 28d.

  In this example, the two field distributions 11 and 12 of the irradiation lines 6a and 6b intersect at an intensity value of 50 percent. If the two curves 11, 12 have a field distribution with the same linear gradient at the edges, the sum 13 of both curves 11, 12 shown in FIG. 10 provides a constant intensity throughout the region. Due to the small residual deviation of the linear gradient and the residual non-uniformity in the strength of the two field distributions 11 and 12, the overall strength may be non-uniform.

  A defined gradient can be achieved when the substrate 6 is not in the focal plane of the condenser lens 3 but is slightly out of focus. The advantage of this scheme is that a very large field of view 13a can be created.

Alternatively, using only one homogenizer in an optical system to create the two fine lines, it is also possible to branch the light to the long axis A _l direction x by the axicon. This solution is not shown here.

As another possibility, the overlapping area 9 can be enlarged. That is, the distance of the imaging optical lens 5 to the substrate 6 is increased, or the angle of the light beam is increased in the long axis _Al direction x. The initial field distributions 21 and 22 of the two rays are shown in FIG. By cutting one or both of the light beams 26a, 26b with the blades 8a, 8b, 8c, 8d, the intersection positions of the irradiation lines 6a and 6b can be selected from a wide range. This is exemplarily shown by the different spreads of the ray distributions 21 and 22 shown in FIG.

  A small gap 24 is formed by cutting at least one of the irradiation lines 26a and 26b in the intersection region 9 of the two irradiation lines 6a and 6b. (Here, both rays 26a and 26b are cut at the overlapping region 9.) For clarity, this state is shown in FIG. 13, where the sum 23 of the intensity distributions 21, 22 in the major axis direction x is It is drawn. The gap 24 may cause a seam on the substrate. (Not shown here, but derived from another silicon microstructure and surface morphology and shown in principle similar to the state shown in FIG. 5.) The location of the seam is two rays 26a, 26b. Alternatively, the irradiation lines 6a and 6b can move over the entire region 9 where they intersect.

Another method for enlarging the size of the field of view will be described with reference to FIG. FIG. 14 shows a plan view of the optical device according to the present invention viewed in the xz-plane. The optical device includes the same optical elements as shown in FIGS. In particular, the optical device includes two sets of cylindrical lens arrays 1a and 1b, and constitutes a two-stage fly-eye type homogenizer and a convex cylindrical condenser lens 3 that are optically activated in the x direction. The optical device further comprises a thin cylindrical lens 2 consisting of a plurality (three in this case) of cylindrical lens pieces 2a, 2b, 2c, a cylindrical lens 4 and a projection element, i.e. a reduction lens, in particular in the y direction referred to in this example. An optically activated cylindrical lens 5 is included. Furthermore, the field of view defining an optical device, for example, field stop 7 is constructed in an intermediate conjugate field plane with respect to the short axis A _s direction y.

Radiation is modified in a way to enlarge the dimensions A _l of the long axis direction x of the field of view 6. Apart from the prior art example shown in FIGS. 6 and 7, the latest projection element 5 is divided into two members 5a and 5b which are joined at a joining position 5s. The upper part of FIG. 15 is an intensity distribution 41 of the irradiation line 6 which is created by the optical device shown in FIG. 14 and is the sum of the distributions 42 and 43 of the light rays 26c and 26d passing through the cemented lenses 5a and 5b, respectively. Show. In the example shown in FIG. 15, the total field dimension 46 is larger than the dimension 47 of the substrate 40 (see the substrate 40 at the bottom of FIG. 15). May be cut on both sides. Currently, the blade 8a limits the spread of the ray 26, so that the field of view 48 shown at the top of FIG. 15 is the actual size.

The radiation 6 which spread A _l in the long axis direction x is reduced, on the irradiation surface of the substrate 40 is scanned by moving the substrate 40 in the scanning direction 45. Due to the cemented lenses 5a and 5b, the intensity distribution 41 of the irradiation line 6 has a gap 49 with respect to the intensity. This gap 49 creates a seam 44 after processing the substrate 40. Depending on the position of the seam 44 after processing, the field size is limited to the same extent on both sides, resulting in the seam 44 being in the middle. Alternatively, the field of view may only be limited on one side and the seam 44 may not be centered. The lower part of FIG. 15 shows a seam 44 that is not centered.

There are two possibilities for adjusting the substrate 40 to fit the field distribution 41.
-The stage on which the substrate 40 is placed moves in the major axis direction x as indicated by reference numeral 45a.
The stage on which the substrate 40 is placed is larger than the substrate 40. The substrate 40 is adjusted to fit the actual field of view using the limiters 8a and 8b.

Third Preferred Embodiment: Changing Angular Distribution and Angular Distance With reference to FIG. 16, a third solution for enlarging the substrate viewing dimension is described. FIG. 16 shows a plan view of the optical device according to the invention in the xz-plane, the functionality of which is known from the prior art except in the case of a special layout. The components of the optical device are those already shown in FIGS. The optical device includes two sets of cylindrical lens arrays 1a and 1b, and constitutes a two-stage fly-eye type homogenizer and a convex cylindrical condenser lens 3 that are optically activated in the x direction. The optical device is further optically activated only in the thin cylindrical lens 2, the cylindrical lens 4 and the projection optical device, i.e. the reduction lens, in particular in the y direction, consisting of a plurality (here three) of cylindrical lens pieces 2a, 2b, 2c. A cylindrical lens 5 is included. A laser beam 10 emitted from a high-power laser light source (not shown) is converted into a thin irradiation line 6 on the substrate surface.

According to the invention, the field spread at the position of the final lens 5 or mirror is much smaller than the size of the field 6 in the substrate. The difference in field size is magnified by performing the following:
The final optical element 5 (note: the expression “final optical element” here means the final lens or mirror used in the projection optical system. The protective window between the projection optical system and the substrate is here In this case, the distance d between the substrate and the substrate (the position of the irradiation line 6) may be enlarged. This is possible when the aperture of the optical element 5 expands in the minor axis direction y or / and when the numerical aperture NA in the minor axis direction y decreases in the substrate. The target value of the distance d is a value larger than 500 mm. Preferably the distance is greater than 600 mm.
The angle α of the beam edge 51 can be enlarged; The energy density of the substrate decreases at the edge due to the cosine law. Further, when the angle α is enlarged, further aberration occurs, and a homogenizer with a correction design is required. This design requires some lenses and possibly at least one aspheric cylindrical lens. The maximum angle α in the major axis direction x should be greater than 7 °. Preferably, the angle α should be greater than 15 °. That is, the distance d is 600mm between the optical element 5 and the substrate, if the angle α is 15 °, field of view _{A l} of 1100mm dimensions by the optical element 5 of 780mm are obtained. If the angle α is 20 °, the dimension of the optical element 5 is further reduced to 660 mm.

It is the figure which looked at the apparatus which concerns on 1st Example from the top, and is a schematic diagram which shows a substrate surface and an irradiation line. It is the figure which looked at the apparatus which concerns on 1st Example of FIG. 1 from the top, and is a schematic diagram which shows the substrate surface and irradiation line after a 1st scanning process. It is the figure which looked at the apparatus which concerns on 1st Example of FIG. 1 and 2 from the top, and is a schematic diagram which shows the substrate surface in the middle of rotating around the rotating shaft. FIG. 4 is a diagram of the apparatus according to the first embodiment of FIGS. 1, 2, and 3, viewed from above, and is a schematic view showing a substrate surface after being rotated 180 ° around a rotation axis. It is the figure which looked at the apparatus which concerns on 1st Example of FIGS. 1-4 from the top, and is a schematic diagram which shows the substrate surface after a 2nd scanning process. It is a schematic diagram which shows the optical device which concerns on the newest technique which produces a thin irradiation line on the irradiation surface of a board | substrate. The optical device is drawn in the xz-plane of the Cartesian coordinate system. It is the schematic diagram which looked at the optical device which concerns on FIG. 6 in yz-plane of the Cartesian coordinate system. It is a schematic diagram which shows the optical device which concerns on this invention which produces a thin irradiation line on the irradiation surface of a board | substrate. The optical device is shown in the xz-plane of the Cartesian coordinate system. FIG. 9 is an intensity distribution of irradiation lines created on an irradiation surface by two optical devices constituting the optical arrangement shown in FIG. 8. FIG. It is the sum of intensity distributions derived from the sum of the intensity distributions shown in FIG. FIG. 9 is another intensity distribution of an irradiation line created on the irradiation surface by two optical devices constituting the optical arrangement shown in FIG. 8. FIG. It is intensity distribution of an irradiation line when a cutting light beam forms an irradiation line in an adjacent region. 13 is a sum of intensity distributions derived from the sum of the intensity distributions shown in FIG. It is a schematic diagram which shows another Example of the optical device which concerns on this invention which produces a thin irradiation line on the irradiation surface of a board | substrate. The optical device is shown in the xz-plane of the Cartesian coordinate system. FIG. 15 is a schematic view of an intensity distribution of irradiation rays produced by the optical device according to FIG. 14 and a substrate surface processed by the optical device according to FIG. 14. It is a schematic diagram of the optical device which concerns on this invention which produces a thin irradiation line on the irradiation surface of a board | substrate. The optical device is drawn in the xz-plane of the Cartesian coordinate system.

Claims (43)

An apparatus for laser annealing of a large substrate,
An optical device for producing a thin radiation line (31) on the radiation surface (36) of the substrate (32), wherein the radiation line (31) is produced from a laser beam and spreads in a first direction (x); _{(a l)} and has a cross section with a spread _{(a s)} in the second direction (y), the spread to the first direction (x) _{(a l)} is the second direction (y) An optical device that is a multiple of the spread (A _s );
-A scanning device configured to scan the irradiation line (6) in the second direction (y, 35) in a first section (37) of the irradiation surface (36) of the substrate (32). ,
After scanning the first section (37), the substrate (32) is rotated by 180 ° around the rotation axis (38) relative to the irradiation line (6), the rotation axis (38) being the irradiation A rotating device perpendicular to the plane (6);
The scanning device moves the second section of the irradiation surface (36) of the substrate (32) adjacent to the first section (37) of the irradiation surface (36) of the substrate (32) to the second section; An apparatus for laser annealing of a large substrate, wherein the apparatus is configured to scan with the irradiation line (31) in a direction (y, 35).   The device according to claim 1, characterized in that the adjusting device adjusts the spread of the irradiation line (31) in the first direction (x) to a predetermined length.   The device according to claim 2, characterized in that the adjusting device comprises at least one blade for cutting at least one side of the radiation (31, 33) in the first direction (x).   4. The apparatus according to claim 2, wherein the adjusting device includes a zoom optical system that reduces a spread of the irradiation lines (31, 33) in the first direction (x). 5.   The apparatus according to any one of claims 1 to 4, characterized in that the rotating device includes a platform on which the substrate (32) is mounted and is rotatable.   6. A device according to claim 5, characterized in that the platform is linearly movable. A method of laser annealing a large substrate (32),
A step of producing a thin irradiation line (31) from the laser beam on the irradiation surface (36) of the substrate (32), the irradiation line (31) extending in the first direction (x) (A _l ) and The cross-section has a spread (A _s ) in the second direction (y), and the spread (A _l ) in the first direction (x) is the spread (A _s ) in the second direction (y). ) Multiple times larger process,
Scanning the first section (37) of the irradiation surface (36) of the substrate (32) with the irradiation line (31) in the second direction (y, 35),
The substrate (32) is rotated 180 ° around the rotation axis (38) with respect to the irradiation line (31) (39), the rotation axis (38) being perpendicular to the irradiation surface (36); When,
The second section of the irradiation surface (36) of the substrate (32) adjacent to the first section (37) of the irradiation surface (36) of the substrate (32) in the second direction (y, 35 ) Is scanned with the irradiation line (31). The spread (A ₁ ) of the irradiation line (31) in the first direction (x) is adjusted to a predetermined length (A _l ) before and / or during the scanning of the first section (37). The method according to claim 7, wherein: The extent (A _l ) of the radiation (31) in the first direction (x) after scanning the first section (37) but before and / or during the scanning of the second section The method according to claim 7 or 8, characterized in that it is adjusted to a predetermined length (A _l ). The spread (A ₁ ) of the irradiation line (31) is defined as a gap between the first section and the second section (37) or an overlap between the first section and the second section (37). The method according to any one of claims 7 to 9, characterized in that the adjustment is made to a predetermined value. An apparatus for laser annealing of a large substrate,
An optical device for producing a thin radiation line (6a) on the radiation surface of the substrate, wherein the radiation line (6a) is produced from a laser beam and spreads in a first direction (x) (A _l ) and It has a cross section with a spread (A _s ) in two directions (y), and the spread (A _l ) in the first direction (x) is the spread (A _s ) in the second direction (y). An optical device that is a multiple of
-A scanning device configured to scan a first section of the irradiated surface of the substrate with the irradiation line (6) in the second direction (y);
-Another optical device for producing another thin irradiation line (6b) on the irradiation surface of the substrate, wherein the other irradiation line (6b) is produced from a laser beam in the first direction (x). spread _{(a l)} and has a cross section with a spread _{(a s)} of the second direction (y), the spread _{(a l)} is the second direction (y in the first direction (x) ) Another optical device which is a multiple of the spread (A _s ) to
The scanning device is configured to scan the second section of the irradiated surface of the substrate in the second direction (y) with the other irradiated line (6b);
The optical device and the other optical device are arranged such that the thin irradiation line (6a) and the other thin irradiation line (6b) form a continuous irradiation line (6) on the irradiation surface of the substrate; An apparatus for laser annealing of a large substrate.   The optical device and the other optical devices are configured such that the continuous radiation (6) is a straight line having a constant intensity along the first direction (x). 11. The apparatus according to 11. The length by which the optical device and / or the other optical device limits the spread (A _l ) of the irradiation line (6a) and / or the other irradiation line (6b) in the first direction (x). characterized in that it comprises a shaft enlargement (a _l) limiting device, according to claim 11 or 12.   The apparatus of claim 13, wherein the restriction device comprises a cutting blade. The optical device and / or the other optical device includes an adjustment device that adjusts the spread (A _l ) of the irradiation line (6a) and / or the other irradiation line (6b) in the first direction. Device according to any one of claims 11 to 14, characterized in that.   Device according to claim 15, characterized in that the adjusting device comprises a movable cutting blade (8a, 8b, 8c, 8d).   The optical device and / or the other optical device, with respect to the irradiated surface of the substrate, the irradiated line (6a, 6b) in which the irradiated line and / or other irradiated line is slightly defocused on the irradiated surface; Device according to any one of claims 11 to 16, characterized in that it is configured to produce A method for laser annealing of large substrates,
A step of producing a thin irradiation line (6a) on the irradiation surface of the substrate from the laser beam, the irradiation line extending in the first direction (x) (A _l ) and in the second direction (y) Having a cross-section with (A _s ), wherein the spread (A _l ) in the first direction (x) is a multiple of the spread (A _s ) in the second direction (y);
Scanning the first section of the irradiated surface of the substrate in the second direction (y) with the irradiation line (6a),
-Creating another thin irradiation line (6b) on the irradiation surface of the substrate, the other irradiation line (6b) being generated from a laser beam and extending in the first direction (x) ( _Al ) and It has a cross section with a spread _{(a s)} of the second direction, the expansion in the first direction (x) _{(a l)} is the extent of _{(a l)} of the second direction (y) Being large in multiples,
-The thin irradiation line (6a) and the other thin irradiation line (6b) are joined to form a continuous irradiation line (6) on the irradiation surface of the substrate;   19. Method according to claim 18, characterized in that the continuous radiation (86) is a straight line having a constant intensity along the first direction (x). And limits the extent (A _l) of the to the first direction of radiation (6a) and / or other of the radiation (6b) (x), according to claim 18 or 19 Method. And adjusting the spread _{(A l)} of the to the first direction of radiation (6a) and / or other of the radiation (6b) (x), any one of claims 18 to 20 The method according to one item.   The irradiation line (6a) and / or the other irradiation line (6b) on the irradiation surface has an intensity of the irradiation line (6a) and / or the other irradiation line (6b) in the major axis direction (x 22. The method according to any one of claims 18 to 21, characterized in that the focus is slightly blurred to have a constant gradient at the edges of An apparatus for laser annealing of a large substrate,
-An optical device for producing a thin irradiation line (6, 6a) on the irradiation surface of the substrate, wherein the irradiation line (6, 6a) is produced from a laser beam (10) in the first direction (x) spread have _{(a l)} and the cross-section of the spread _{(a s)} in the second direction (y), to the extent _{(a l)} is the second direction to the first direction (x) (y) An optical device that is large in multiples of the spread (A _s ), and configured to scan the first section of the irradiated surface of the substrate in the second direction (y) with the irradiated lines (6, 6a) And a scanning device
The optical device comprises at least two optical elements (5a, 5b) having refractive power and being an integral part of the projection / reduction optical system for producing the irradiation line (6) on the irradiation surface; The at least two optical elements (5a, 5b) are configured adjacent to each other in the first direction (x),
-Another optical device for producing another thin irradiation line (6b) on the irradiation surface of the substrate, the other irradiation line (6b) being produced from a laser beam in the first direction (x) spread _{(a l)} and has a cross section with a spread _{(a s)} of the second direction (y), the spread _{(a l)} is the second direction (y in the first direction (x) the spread (increased in multiples of a _s) of the), in order to produce the radiation (6a) on the irradiated surface, the optical device has a refractive power, an integral part of the projection / reduction optics In order to produce the other irradiation line (6b) on the irradiation surface, including the at least one optical element (5), the other optical device has a refractive power and has another projection / reduction optical system. At least one other optical element that is an integral part ( A large substrate, wherein at least one of the optical elements (5) and at least one of the other optical elements (5) are adjacent to each other in the first direction (x) For laser annealing.   24. Device according to claim 23, characterized in that the plurality of optical elements (5a, 5b) and / or the one optical element (5) and the other optical element (5) are lenses or mirrors.   The plurality of optical elements (5a, 5b) and / or the one optical element (5) and the other optical element (5) are the latest optical elements having refractive power used in the projection / reduction optical system ( Device according to claim 23 or 24, characterized in that it is 5,5a, 5b). An apparatus for laser annealing of a large substrate,
An optical device that produces a thin irradiation line (6) on the irradiation surface of the substrate, the irradiation line (6) being produced from a laser beam (10) and spreading in a first direction (x) (A _l ) And a spread (A _s ) in the second direction (y), and the spread (A _l ) in the first direction (x) is the spread in the second direction (y) ( An optical device that is a multiple of A _s ),
-A scanning device configured to scan a first section of the irradiated surface of the substrate with the irradiation line (6) in the second direction (y);
The optical device comprises a final optical element (5) that has refractive power and is an integral part of a projection / reduction optical system, in order to produce the irradiation line (6) on the irradiation surface, Apparatus for laser annealing of a large substrate, characterized in that the distance (d) between the final optical element (5) and the irradiation surface of the substrate is greater than 500 mm.   27. Device according to claim 26, characterized in that the distance (d) between the final optical element (5) and the irradiation surface of the substrate is greater than 600 mm.   28. Device according to claim 27, characterized in that the distance (d) between the final optical element (5) and the irradiation surface of the substrate is greater than 700 mm.   29. Device according to claim 28, characterized in that the distance (d) between the final optical element (5) and the irradiation surface of the substrate is greater than 800 mm.   30. Device according to claim 29, characterized in that the distance (d) between the final optical element (5) and the irradiation surface of the substrate is greater than 900 mm.   Device according to claim 30, characterized in that the distance (d) between the final optical element (5) and the irradiation surface of the substrate is greater than 1000 mm. The optical device expands the laser beam (10) in the first direction (x) to a spread (A ₁ ) of the irradiation line (6) in the first direction (x) at a divergence angle (α). 32. Device according to any one of claims 26 to 31, characterized in that it comprises a longitudinal beam expansion device (1a, 1b, 3), the divergence angle ([alpha]) being greater than 7 [deg.].   Device according to claim 32, characterized in that the divergence angle (α) is greater than 15 °.   34. Device according to claim 33, characterized in that the divergence angle ([alpha]) is greater than 20 [deg.].   Device according to claim 34, characterized in that the divergence angle (α) is greater than 25 °.   36. Device according to claim 35, characterized in that the divergence angle ([alpha]) is greater than 30 [deg.].   37. Device according to claim 36, characterized in that the divergence angle ([alpha]) is greater than 35 [deg.]. An apparatus for laser annealing of a large substrate,
An optical device that produces a thin irradiation line (6) on the irradiation surface of the substrate, the irradiation line (6) being produced from a laser beam (10) and spreading in a first direction (x) (A _l ) And a spread (A _s ) in the second direction (y), and the spread (A _l ) in the first direction (x) is the spread in the second direction (y) ( An optical device that is a multiple of A _s ),
-A scanning device configured to scan a first section of the irradiated surface of the substrate in the second direction with the irradiation line (6);
The optical device expands the laser beam (10) in the first direction (x) to a spread (A ₁ ) of the irradiation line (6) in the first direction (x) at a divergence angle (α). An apparatus for laser annealing of a large substrate, including a long axis direction (A _l ) beam expanding device (1a, 1b, 3), and having a divergence angle (α) larger than 7 °.   39. Device according to claim 38, characterized in that the divergence angle ([alpha]) is greater than 15 [deg.].   40. Device according to claim 39, characterized in that the divergence angle ([alpha]) is greater than 20 [deg.].   41. Device according to claim 40, characterized in that the divergence angle ([alpha]) is greater than 25 [deg.].   42. Device according to claim 41, characterized in that the divergence angle ([alpha]) is greater than 30 [deg.].   43. Device according to claim 42, characterized in that the divergence angle ([alpha]) is greater than 35 [deg.].

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