JP2009289922A - Mask, laser crystallization apparatus, laser crystallization method, crystal material, and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask, a laser crystallization apparatus, laser crystallization method, crystal material, and a semiconductor device, which are capable of forming a square crystal larger than before. <P>SOLUTION: A slit for a mask element group for seed crystal formation is arranged on a mask so that a seed crystal surrounded by a crystal grain boundary of nearly closed loop may be formed by laser beam irradiation on a mask. Regarding an X-Y rectangular coordinate with an origin at a specific position in the seed crystal, k is set to be a natural number from 1 to 4; in the k-th quadrant, an X-axis positive direction is set to be kX+, an X-axis negative direction kX-, a Y-axis positive direction kY+ and a Y-axis negative direction kY-. After that, a slit for a mask element group for seed crystal expansion, which follows the mask element group for seed crystal formation, is arranged so that the seed crystal surrounded by the crystal grain boundary of nearly closed group may be expanded in the direction of 1X+, 1Y+, 2X-, 2Y+, 3X-, 3Y-, 4X+ and 4Y-, by the control of the irradiation timing of laser beams irradiated through a mask element group for seed crystal expansion following the mask element group for seed crystal formation and also by the control of the relative movement of the mask. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a laser crystallization apparatus that forms a crystal by laser light irradiation, a mask used in the apparatus, a laser crystallization method, a crystal material, and a semiconductor element.

  In recent years, SOG (System on Glass) technology for manufacturing a semiconductor device using a silicon thin film obtained by forming a silicon thin film on a glass substrate has attracted attention as a semiconductor device manufacturing technology. As a technique for producing a silicon thin film, a laser crystallization technique classified as a lateral growth method is known. When this laser crystallization technique is used, a crystal having a long crystal length in which the orientation is aligned in the crystal growth direction can be obtained. Therefore, the laser crystallization technique is particularly attracting attention.

  In addition, as one of the lateral growth methods, the silicon thin film in the laser light irradiation region is melted over the entire thickness direction by irradiating the silicon thin film with pulsed laser light that has passed through the slit of the mask. Then, an SLS (Sequential Lateral Solidification) method is known in which crystallization is performed by repeating a growth process for crystal growth thereafter.

  Patent Document 1 discloses one mode of the SLS method. Specifically, in Patent Document 1, by irradiating a silicon thin film with a pulsed laser beam having a fine width, the silicon thin film is melted over the entire region in the thickness direction of the irradiation region of the pulsed laser light, and then solidified. In this way, crystallization is performed.

  FIG. 96 is a diagram showing a mask 101 in the form described in Patent Document 1. In FIG. The mask 101 includes first to n-th mask elements (mask element length: M) in which a slit pattern including a horizontally long slit (opening) and a light-shielding portion is formed. , And the nth mask element 101-n (n = 4 in the example shown in the figure). By irradiation with laser light through each of the first to nth mask elements, first to nth irradiation regions are formed on the irradiation object 80, respectively.

  Further, in each of the first to n-th mask elements, as shown in the figure, the respective slits are arranged in a stepped manner such as slits 101-1a, slits 101-2a,..., Slits 101-4a ( Hereinafter, the slits 101-1a to 101-4a are referred to as slit groups 101a). Further, in the mask 101, as shown in the figure, slits are arranged in a stepped manner such as slits 101-1b, slits 101-2b,..., Slits 101-4b (hereinafter referred to as slits from the slits 101-1b to 101-1b). 101-4b is referred to as a slit group 101b).

  Furthermore, such step-like slit groups are arranged in the vertical direction (direction perpendicular to the arrow direction in the figure) in the order of 101a and 101b. Further, by the relative movement of the mask 101 in the direction of the arrow in the figure, the laser irradiation region by the slit 101-4a at the uppermost part (the last part of the staircase) in the slit group 101a is located above the slit group 101b. A slit group 101a and a slit group 101b are formed so as to partially overlap the irradiation region formed by the slit 101-1b at the lowermost part (the lowest part of the stairs).

  FIG. 97 is a diagram showing a crystal growth state in the process of growing a crystal using the mask 101.

  Here, FIG. 97A shows a laser beam irradiation pattern formed on the substrate 80 (specifically, on the silicon thin film) by the mask 101. FIG. By irradiation with laser light having such an irradiation pattern (first irradiation), crystal growth occurs at each position irradiated with laser light through a slit, as shown in FIG. 97 (b). During this crystal growth, from the region corresponding to the end of the slit (upper and lower ends in FIG. 97 (a)) in the direction (Y-axis direction) perpendicular to the direction of relative movement of the mask, the center of the slit Crystal growth occurs toward the region corresponding to the part. Note that FIG. 97B shows a crystal formed on the substrate 80 by the laser beam having the irradiation pattern shown in FIG.

  FIG. 98 is a diagram showing the state of crystals growing in the 101st region on the substrate 80 shown in FIG. 97 in association with FIG.

  Here, FIG. 98A shows a crystal formed in the 101st region by the first irradiation. As shown in the figure, a crystal 101-A is formed in a region corresponding to the slit 101-1a, and a crystal 101-B is formed in a region corresponding to the slit 101-1b. Note that vertical lines (lines perpendicular to the direction of relative movement of the mask) in the crystal 101-A and the crystal 101B in the figure schematically show crystal grain boundaries that occur along the crystal growth direction. . Further, the crystals grown toward the center from the positions corresponding to the both ends of the slit collide at the positions corresponding to the center of the slit, and as a result, shown as two horizontal lines as shown in FIG. The ridge 101-AR and the ridge 101-BR, which are protrusions, are formed.

  In FIG. 97 (c), the mask 101 is moved relative to the substrate 80 in the direction of the arrow in FIG. 97 (a) by the length M of the mask element, and then irradiated with laser light (second irradiation). In this case, the crystal formed on the substrate 80 is shown.

  By such second irradiation, laser light irradiation is performed on a region partially overlapping with the crystal 101-A formed by the first irradiation and a region partially overlapping with the crystal 101-B. . As a result, while removing the ridge 101-AR of the crystal 101-A and the ridge 101-BR of the crystal 101-B, the crystal growth in the Y direction (takeover growth) for the crystal 101-A and the crystal 101-B Crystal growth in the Y direction occurs. Therefore, a crystal 102-A and a crystal 102-B are formed as shown in FIG.

  Thereafter, by repeating the same movement and irradiation operations, as shown in FIGS. 97 (d), 97 (e), 98 (c), and 98 (d), the laser irradiation region by the slit group 101a is obtained. Are sequentially overlapped in the Y direction, and the laser irradiation regions by the slit groups 101b are sequentially overlapped in the Y axis direction. As a result, with the crystals 101-A and 101-B formed by the first irradiation as seed crystals, as shown in FIG. 98 (d), the final crystal 104-A and the final crystal 104, which are successively inherited and grown in the Y-axis direction, are obtained. -B is formed.

  However, in the SLS method described in Patent Document 1, an elongated crystal whose longitudinal direction is the direction perpendicular to the direction of the movement is formed by repeating the movement of the slit and the irradiation of the laser light described above. For this reason, when a TFT (Thin Film Transistor) is manufactured using such a crystal, the TFT characteristics differ greatly depending on the angle formed by the direction in which the TFT current flows and the longitudinal direction of the crystal. Specifically, when the direction in which the TFT current flows and the longitudinal direction of the growth crystal are parallel, the TFT characteristics are best, whereas the direction in which the TFT current flows and the longitudinal direction of the growth crystal are perpendicular to each other. The TFT characteristics are the worst. Thus, when crystallized by the SLS method, uniform TFT characteristics cannot be obtained due to crystal anisotropy.

  On the other hand, Patent Document 2 discloses a laser crystallization technique using a mask in which a slit different from that of Patent Document 1 is formed. In Patent Document 2, by using a mask in which different slits are formed, it is possible to form a square crystal that has also grown in the short direction of the crystal, and as a result, the anisotropy can be improved. Are listed.

  FIG. 99 is a view showing a mask 201 in the form described in Patent Document 2. In FIG. The mask 201 includes first to fourth mask elements (mask element length: M) in which a slit pattern including a long slit (opening) and a light shielding portion is formed. 1, the second mask element 201-2, the third mask element 201-3, and the fourth mask element 201-4 are provided in this order. By irradiation with laser light through the slits of the first to fourth mask elements, first to fourth irradiation regions are formed on the substrate 80 (specifically, on the silicon thin film), respectively.

  Further, in the mask 201, as shown in the figure, a horizontally long slit 201-1a and a horizontally long slit 201-3a (referred to as a slit group h-201a) and a horizontally long Slit 201-1b and horizontally long slit 201-3b (referred to as slit group h-201b), vertically long (the relative movement direction of the mask is short), and slit 201-2a and vertically long slit 201-4a ( A slit group v-201a) and a longitudinal slit 201-2b and a longitudinal slit 201-4b (referred to as a slit group v-201a) are arranged.

  Further, the horizontally long slit groups are arranged in the vertical direction (direction perpendicular to the arrow direction in the figure) in the order of h-201a and h-201b, and the vertically long slit groups are in the order of v-201a and v-201b. Are aligned in the left-right direction (the arrow direction in the figure).

  Further, by moving the mask 201 relative to the arrow direction in the figure by 2M, the laser irradiation region by the slit 201-3a of the third mask element 201-3 becomes the slit 201-1a of the first mask element 201-1 and It arrange | positions so that both may partly overlap with the laser irradiation area | region by the slit 201-1b. Further, by moving the mask 201 relative to the direction of the arrow in the figure by M, the laser irradiation region by the slit 201-4a of the fourth mask element 201-4 becomes the slit 201-2a of the second mask element 201-2. And the laser irradiation region by the slit 201-2b are arranged so as to partially overlap each other.

  FIG. 100 is a diagram illustrating a crystal growth state in the process of growing a crystal using the mask 201.

  Here, FIG. 100A is a diagram showing an irradiation pattern of a laser beam formed on the substrate 80 (specifically, on a silicon thin film) by the mask 201. FIG. By laser beam irradiation (first irradiation) having such an irradiation pattern, crystal growth occurs at each position where the laser beam is irradiated through the slit, as shown in FIG. In this crystal growth, from the region corresponding to the end of the slit (upper and lower ends of FIG. 100A) in the direction (Y-axis direction) perpendicular to the direction of relative movement of the mask, the center of the slit Crystal growth occurs toward the region corresponding to the part. FIG. 100B shows a crystal formed on the substrate 80 by the laser beam having the irradiation pattern shown in FIG.

  FIG. 101 is a diagram showing the state of a crystal grown in the 201st region on the substrate 80 shown in FIG. 100 in association with FIG.

  Here, FIG. 101A shows a crystal formed in the 201st region by the first irradiation. As shown in the figure, a crystal 201-A is formed in a region corresponding to the slit 201-1a, and a crystal 201-B is formed in a region corresponding to the slit 201-1b. Note that vertical lines (lines perpendicular to the direction of relative movement of the mask) in the crystal 201-A and the crystal 201B in the figure schematically show crystal grain boundaries that occur along the crystal growth direction. . Further, the crystals grown toward the center from the positions corresponding to the both ends of the slit collide at the positions corresponding to the center of the slit, and as a result, shown as two horizontal lines as shown in FIG. The ridge 201-AR and the ridge 201-BR, which are protrusions, are formed.

  In FIG. 100 (c), the mask 201 is moved relative to the substrate 80 in the direction of the arrow in FIG. 100 (a) by the length M of the mask element, and then irradiated with laser light (second irradiation). In this case, the crystal formed on the substrate 80 is shown.

  With such second irradiation, laser irradiation is performed by the slits 201-2a and 201-2b of the second mask element 201-2 in the 201st region shown in FIG. Thereby, the crystal 202-A is formed so as to intersect with the crystal 201-A formed by the first irradiation, and the crystal 202-B is formed so as to intersect with the crystal 201-B.

  In addition, crystal growth (takeover growth) occurs in the X-axis direction and Y-axis direction in FIG. 101A with respect to the crystals 201-A and 201-B grown in the Y-axis direction. As a result, as shown in FIG. 101 (b), rectangular seed crystals 202-1, seed crystals 202-2,..., Seed crystals 202-6 are formed. Here, the seed crystal refers to a crystal that does not include a ridge in the crystal (that is, a crystal surrounded by the ridge). More specifically, the seed crystal refers to a crystal surrounded by a continuous crystal grain boundary or a crystal grain boundary partially discontinuous.

  In FIG. 100D, the mask 201 is further moved relative to the substrate 80 in the direction of the arrow in FIG. 100A by the length M of the mask element, and then irradiated with laser light (third irradiation). FIG. 6 is a diagram showing a crystal formed on a substrate 80 in the case of

  With such third irradiation, laser irradiation is performed by the slit 201-3a and the slit 201-3b of the third mask element 201-3 in the 201st region shown in FIG. Thereby, as shown in FIG. 100 (d), the crystal 203-A is partially overlapped with both the crystal 201-A and the crystal 201-B formed by the first irradiation, and the first A crystal 203-B is formed so as to partially overlap the crystal 201-B formed by irradiation.

  As a result, crystal growth (takeover growth) occurs in the Y-axis direction for the seed crystals such as the seed crystal 202-1, the seed crystal 202-2, ..., the seed crystal 202-6. As a result, as shown in FIG. 101C, square crystals such as a square crystal 203-1, a square crystal 203-2,..., A square crystal 203-6, which are larger than the seed crystal, are formed.

  In FIG. 100E, the mask 201 is further moved relative to the substrate 80 in the direction of the arrow in FIG. 100A by the length M of the mask element, and then irradiated with laser light (fourth irradiation). FIG. 6 is a diagram showing a crystal formed on a substrate 80 in the case of

  By such fourth irradiation, laser irradiation is performed by the slit 201-4a and the slit 201-4b of the fourth mask element 201-4 in the 201st region shown in FIG.

  Thereby, as shown in FIG. 100 (e), a crystal 204-A is partially overlapped with both the crystal 202-A and the crystal 202-B formed by the second irradiation, and the second A crystal 204-B is formed so as to partially overlap the crystal 201-B formed by irradiation.

  As a result, crystal growth (takeover growth) occurs in the X-axis direction for the crystals 203-1, the crystal 203-2,..., The crystal 203-6. Thereby, as shown in FIG. 101 (d), square crystals such as a square crystal 204-1, a square crystal 204-2,..., A square crystal 204-9 larger than the seed crystal are formed.

Thus, according to the laser crystallization method described in Patent Document 2, a crystal formed in a region where the irradiation patterns of the first irradiation and the second irradiation intersect is used as a seed crystal, and this seed crystal is applied to the third irradiation. And it can be enlarged by the irradiation pattern of the fourth irradiation. This makes it possible to produce a square crystal that has also grown in the X-axis direction compared to the crystal obtained by the laser crystallization method described in Patent Document 1. If a TFT is formed using such a crystal, a TFT having uniform characteristics can be obtained regardless of the direction in which the TFT current flows.
JP 2003-51445 A Japanese Patent Laid-Open No. 2003-22969

  Here, paying attention to the square crystal 204-1 shown in FIG. 101 (d), the process of growing the crystal 201-1 into the square crystal 204-1 will be described with reference to FIGS.

  FIG. 102 is a diagram showing the crystal 201-1 formed by the first irradiation. FIG. 103 is a diagram showing the crystal 202-1 formed by the second irradiation. FIG. 104 is a diagram showing the crystal 203-1 formed by the third irradiation. FIG. 105 is a diagram showing the crystal 204-1 formed by the fourth irradiation.

  102 to 105, a region surrounded by a thin line indicates a region that is crystallized by each irradiation, and a region surrounded by a dotted line is crystallized by irradiation one time before each irradiation. A region surrounded by a thick line indicates a crystal that is crystallized by the irradiation, and a hatched region indicates a crystal formed by irradiation one time before each irradiation.

  A crystal 201-1 in FIG. 102 is a needle-like crystal that has grown from the end of the irradiation region described above toward the center by the first irradiation in the direction of the arrow in FIG. Next, by the second irradiation, as shown in FIG. 103, the crystal 201-1 is stretched to the left in the figure, and a rectangular seed crystal 202-1 is formed. Further, by the third irradiation, as shown in FIG. 104, the seed crystal 202-1 is expanded upward in the same figure, and a crystal 203-1 is formed. As a result of the fourth irradiation, as shown in FIG. 105, the crystal 203-1 is stretched to the right in the figure, and finally a square crystal 204-1 is formed. Thereby, crystallization is completed. FIG. 106 is a diagram showing the relationship between the seed crystal and the finally formed square crystal (square crystal 204-1).

  FIG. 107 is a diagram showing an XY orthogonal coordinate system with the centroid P of the seed crystal 202-1 formed by the first irradiation and the second irradiation as the origin. Here, the right direction in each of FIGS. 102 to 105, which is opposite to the direction of relative movement of the mask (that is, the direction of movement of the stage), is the positive direction in the X-axis direction, and the upward direction in each figure is Y. The axial direction is positive.

  Furthermore, as shown in FIG. 107, the positive direction in the X-axis direction in the k-th quadrant (k = 1, 2, 3, 4) in the XY orthogonal coordinate system is kX +, and the negative direction in the X-axis direction is kX. The positive direction in the Y-axis direction is expressed as kY +, and the negative direction in the Y-axis direction is expressed as kY-. Further, 1X + and 4X + which are positive directions in the X-axis direction are collectively X +, 2X- and 3X- which are negative directions in the X-axis are collectively X-, and a positive direction in the Y-axis direction. 1Y + and 2Y + are collectively expressed as Y +, and 3Y− and 4Y− as negative directions in the Y-axis direction are collectively expressed as Y−.

  Further, as shown in the figure, X + indicating the positive direction in the X-axis direction and X- indicating the negative direction in the X-axis direction are collectively X, and Y + and Y indicating the positive direction in the Y-axis direction. Y- indicating the negative direction in the axial direction is collectively expressed as Y. That is, X indicates the X-axis direction (including a positive direction and a negative direction), and Y indicates the Y-axis direction (including a positive direction and a negative direction).

  If the definition of the direction and direction shown in FIG. 107 is used, the direction in which the seed crystal is stretched in the laser crystallization method described in Patent Document 2 is 1X + in the first quadrant as shown in FIGS. The second quadrant is expanded only in one direction of 2Y +, the fourth quadrant is expanded only in one direction of 4X +, and is not expanded at all in the third quadrant.

  As described above, in the laser crystallization method described in Patent Document 2, the seed crystal is expanded only in four directions (1X +, 4X +, 1Y +, 2Y +) among the eight directions that can be expanded. In other words, the seed crystal is stretched only in the positive direction (1X +, 4X +) in the X-axis direction and in the positive direction (1Y +, 2Y +) in the Y-axis direction.

  102 to 105, the formation process of the square crystal 204-1 in FIG. 101 has been described, but the other square crystals (204-2 to 204-6) are similar to the square crystal 204-1. The following can be said from the above.

  In the square crystal 204-2, the seed crystal is not expanded into the second quadrant, and is expanded only in four directions among the eight directions in which the seed crystal can be extended. Further, the square crystal 204-3 does not extend the seed crystal to the third quadrant, and extends only in four directions out of the eight directions in which the seed crystal can be expanded. In addition, the square crystal 204-4 is not expanded into the fourth quadrant, and is expanded only in four directions out of the eight directions in which the seed crystal can be expanded. In addition, the square crystal 204-5 is not expanded into the first quadrant, and is expanded only in four directions out of the eight directions in which the seed crystal can be expanded. In addition, the square crystal 204-6 is not expanded into the fourth quadrant, and is expanded only in four directions out of the eight directions in which the seed crystal can be expanded.

  As described above, in the laser crystallization method described in Patent Document 2, the seed crystal can be stretched when the seed crystal formed by the first irradiation and the second irradiation is stretched by the third irradiation and the fourth irradiation. This is a laser crystallization method in which a seed crystal is stretched only in four directions out of eight directions.

That is, the laser crystallization method described in Patent Document 2 is a method of extending the seed crystal in the direction indicated by any one of the following (1) to (4) when considered for each seed crystal.
(1) Positive direction in the X-axis direction (1X +, 4X +) and positive direction in the Y-axis direction (1Y +, 2Y +)
(2) Positive direction in the X-axis direction (1X +, 4X +) and negative direction in the Y-axis direction (3Y−, 4Y−)
(3) Negative direction in the X-axis direction (2X−, 3X−) and positive direction in the Y-axis direction (1Y +, 2Y +)
(4) Negative direction in the X-axis direction (2X−, 3X−) and negative direction in the Y-axis direction (3Y−, 4Y−)
For this reason, if the slit width is a fixed value, only a square crystal having a size determined by the width of the slit or the width of the region irradiated with the laser beam superimposed can be obtained.

  Here, when a slit having a width wider than the slit of the mask 201 in FIG. 100 is used, the irradiation pattern by the first irradiation and the irradiation pattern by the second irradiation are compared with the case of using the slit of the mask 201 in FIG. The area where and intersects becomes wider. Therefore, it is possible to form a larger square crystal by stretching the crystal formed in the intersecting region.

  However, when a slit having a width wider than the slit of the mask 201 in FIG. 100 is used, in order to obtain a sufficiently long crystal growth distance, the laser beam is emitted with a higher irradiation energy than in the case of using the slit of the mask 201 in FIG. Need to be irradiated. However, if the laser beam irradiation energy is too high, the substrate may be damaged or the film may be peeled off.

  In addition, as the crystal growth distance in one laser light irradiation increases, the crystal width tends to become non-uniform. For this reason, when a seed crystal is formed by inheriting and growing a crystal formed by the first irradiation in a region where the irradiation pattern by the first irradiation and the irradiation pattern by the second irradiation intersect, Cracks (grain cracks) are likely to occur. Even if the seed crystal including such grain cracks is stretched by the third irradiation and the fourth irradiation, only a square crystal having poor crystallinity can be obtained.

  Thus, even when a wide slit is used, there is a limit to increasing the width of the slit, and thus there is a limit to the size of the obtained square crystal.

  Therefore, when a TFT is manufactured using a square crystal formed by the laser crystallization method described in Patent Document 2, depending on the size of the channel region of the TFT, a large number of crystal grain boundaries may be included in the channel. become. Therefore, in such a case, only TFTs with low characteristics can be obtained.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to provide a mask, a laser crystallization apparatus, a laser crystallization method, a crystal material, and a semiconductor element capable of forming a larger square crystal than in the past. Is to provide.

  According to an aspect of the present invention, the mask has an opening, and the irradiation pattern is irradiated on the object to be processed by irradiating the object to be processed relatively moving through the opening. Comprising a seed crystal formation mask element group and a seed crystal extension mask element group arranged along the moving direction, and is applied to a substantially closed-loop grain boundary by laser light irradiation. An opening of the seed crystal forming mask element group is arranged so that an enclosed seed crystal is formed, and k is a natural number of 1 to 4 in an XY orthogonal coordinate system having a specific position in the seed crystal as an origin. And the X-axis positive direction in the k-th quadrant is kX +, the X-axis negative direction is kX-, the Y-axis positive direction is kY +, and the Y-axis negative direction is kY-. A laser beam irradiated through a mask element group for seed crystal stretching. By controlling the irradiation timing of light and controlling the movement, the seed crystal surrounded by the substantially closed-loop crystal grain boundary is formed into 1X +, 1Y +, 2X−, 2Y +, 3X−, 3Y−, 4X +, and 4Y. The openings of the seed crystal stretching mask element group are arranged so as to extend in the respective directions of −.

  Further, at least one of the two directions 1Y + and 2Y +, the two directions 2X− and 3X−, the two directions 3Y− and 4Y−, and the two directions 1X + and 4X + It is preferable that an opening of the seed crystal stretching mask element group is disposed so as to simultaneously stretch the seed crystal in two directions.

  The seed crystal forming mask element group has an X-axis positive direction as X +, an X-axis negative direction as X-, a Y-axis positive direction as Y +, and a Y-axis negative direction as Y-, and n is 1 or more. As a natural number, a fourth n-3 stretch mask element having a fourth n-3 opening for stretching the seed crystal in the Y + direction and a fourth n-2 for stretching the seed crystal in the Y- direction. A fourth n-2 stretch mask element having an opening, a fourth n-1 stretch mask element having a fourth n-1 opening for stretching the seed crystal in the X + direction, and the seed crystal in the X- direction. And a fourth n mask element having a fourth n opening for stretching the.

  Further, the openings of the fourth n-3 opening are arranged in parallel regardless of the value of n, and the openings of the fourth n-2 opening are parallel regardless of the value of n. Each opening of the 4n-1 opening is arranged in parallel regardless of the value of n, and each opening of the fourth n opening is parallel regardless of the value of n. It is preferable that it is arranged.

  Further, when s is a natural number of 1 or more and the irradiation pattern formed on the substrate by the sth opening of the sth expansion mask element is the sth irradiation pattern, the first irradiation pattern when the value of n is 1 is The second irradiation pattern when the value of n overlaps with the seed crystal so as to include at least a part of the grain boundaries of the first quadrant and the second quadrant, and the crystal in the at least the third quadrant and the fourth quadrant The third irradiation pattern overlaps with the seed crystal so as to include a part of the grain boundary and the value of n is 1, so that the seed irradiation includes at least a part of the crystal grain boundary in the first quadrant and the fourth quadrant. The fourth irradiation pattern when it overlaps with the crystal and the value of n is 1 has the first to fourth openings so as to overlap with the seed crystal so as to include at least part of the grain boundaries in the second quadrant and the fourth quadrant. It is preferable that the parts are arranged.

  For each of the mask elements of the 4n-3 expanded mask element, the 4n-2 expanded mask element, the 4n-1 expanded mask element, and the 4n expanded mask element, the mask element when the value of n is k is The mask element when the value of n is k + 1 is the (k + 1) th mask element, the opening of the kth mask element is the kth opening, and the k + 1th mask element The opening is the (k + 1) th opening, the center line in the first direction of the kth opening is the kth centerline in the first direction, and the centerline in the second direction of the kth opening is in the second direction. The k + 1 center mask element, the (k + 1) th mask element is disposed on the opposite side of the seed crystal formation mask element group with respect to the kth mask element. k + 1th A portion of the opening overlaps the kth centerline in the first direction on the one direction side in the second direction, and for the 4n-2 expanded mask element, the k + 1th mask element is the kth mask. The element is arranged on the opposite side of the seed crystal forming mask element group with respect to the element, and a part of the (k + 1) th opening is formed on the other direction side of the second direction with the kth center line in the first direction. Regarding the overlapping 4n-1 stretched mask element, the (k + 1) th mask element is arranged on the opposite side of the seed crystal formation mask element group with respect to the kth mask element, and one of the (k + 1) th opening portion. Part overlaps the kth centerline in the second direction on the one direction side in the first direction, and for the 4nth stretched mask element, the k + 1th mask element is seeded with respect to the kth mask element. Together arranged on a side opposite to the use mask element group, k + 1-th part of the opening is preferably overlapping with the k-th of the center line in the second direction in the other direction side of the first direction.

  Also, the 4n-3 expanded mask element, the 4n-2 expanded mask element, the 4n-1 expanded mask element, and the 4n expanded mask element are arranged in this order regardless of the value of n. It is preferable.

  Also, the 4n-3 expanded mask element, the 4n-1 expanded mask element, the 4n-2 expanded mask element, and the 4n expanded mask element are arranged in this order regardless of the value of n. It is preferable.

  A kth mask element for the 4n-3 expanded mask element; a k + 1th mask element for the 4n-3 expanded mask element; a kth mask element for the 4n-2 expanded mask element; The (k + 1) th mask element for the 4n-2 expanded mask element, the kth mask element for the 4n-1 expanded mask element, the (k + 1) th mask element for the 4n-1 expanded mask element, and the 4nth It is preferable that the kth mask element for the extended mask element and the (k + 1) th mask element for the 4nth extended mask element are arranged in this order regardless of the value of k.

  A kth mask element for the 4n-3 expanded mask element; a kth mask element for the 4n-2 expanded mask element; a k + 1th mask element for the 4n-3 expanded mask element; The (k + 1) th mask element for the 4n-2 expanded mask element, the kth mask element for the 4n-1 expanded mask element, the kth mask element for the 4nth expanded mask element, and the 4n-1 It is preferable that the (k + 1) th mask element for the extended mask element and the (k + 1) th mask element for the fourth n extended mask element are arranged in this order regardless of the value of k.

  A kth mask element for the 4n-3 stretched mask element, a kth mask element for the 4n-2 stretched mask element, a kth mask element for the 4n-1 stretched mask element, The kth mask element for the 4n expanded mask element, the (k + 1) th mask element for the 4n-3 expanded mask element, the (k + 1) th mask element for the 4n-2 expanded mask element, and the 4n−1. It is preferable that the (k + 1) th mask element for the extended mask element and the (k + 1) th mask element for the fourth n extended mask element are arranged in this order regardless of the value of k.

  Further, the mask element group for seed crystal extension has a second n-1 A opening for extending the seed crystal in the Y + direction and a seed crystal in the Y− direction, where n is a natural number of 1 or more. A 2n-1 stretch mask element having a 2n-1 B opening, a 2n A opening for stretching the seed crystal in the X + direction, and a second n for stretching the seed crystal in the X- direction. And a second n stretch mask element having a B opening.

  Further, the openings of the (2n-1) th A opening are arranged in parallel regardless of the value of n, and the openings of the (2n-1) th B opening are independent of the value of n. Each of the openings of the second n-th A opening is arranged in parallel with each other regardless of the value of n. The openings of the B opening are preferably arranged in parallel with each other regardless of the value of n, and are arranged in parallel with the 2nth A opening.

  Further, t is a natural number of 1 or more, and the irradiation pattern formed on the substrate is formed by the tA irradiation pattern and the tth B opening of the tth extension mask by the tth A opening of the tth extension mask. When the irradiation pattern formed on the substrate is the tB irradiation pattern, the first A irradiation pattern when the value of n is 1 includes at least part of the crystal grain boundaries in the first quadrant and the second quadrant. The 1B irradiation pattern when it overlaps with the seed crystal and the value of n is 1 overlaps with the seed crystal so that it includes at least a part of the crystal grain boundaries in the third and fourth quadrants, and the value of n is 1 The second A irradiation pattern overlaps with the seed crystal so as to include at least part of the grain boundaries of the first quadrant and the fourth quadrant, and the second B irradiation pattern when the value of n is 1 is at least the second Includes part of the grain boundaries in quadrants and quadrants As such, so as to overlap with the seed crystal, it is preferable that the opening is located.

  Further, regarding the 2n-1 expanded mask element and the 2n expanded mask element, the mask element when the value of n is k is the kth mask element, and the mask element when the value of n is k + 1 is k + 1. And the two openings of the kth mask element are the kth A opening and the kth B opening, and the two openings of the (k + 1) th mask element are k + 1th. And the (k + 1) th B opening, and the kth A centerline in the first direction is the kth A centerline in the first direction, and the kth A opening The center line in the second direction of the opening is the kth A centerline in the second direction, and the centerline in the first direction of the kth B opening is the kth B centerline in the first direction. And the center line in the second direction of the kth B opening. Assuming the kth B center line in two directions, for the 2n-1 stretched mask element, the (k + 1) th mask element is arranged on the opposite side of the seed crystal formation mask element group with respect to the kth mask element. In addition, a part of the (k + 1) th A opening overlaps the kth A center line in the first direction on one side in the second direction, and one of the (k + 1) th B opening. Portion overlaps the kth B centerline in the first direction on the other direction side in the second direction, and for the second n stretched mask element, the (k + 1) th mask element is the seed for the kth mask element. A part of the (k + 1) th A opening is arranged on the side opposite to the crystal forming mask element group, and the kth A center line in the second direction on the one direction side in the first direction Overlap and k + 1 Part of the opening of the B is preferably overlapping with the center line of the k-th B in the second direction in the other direction side of the first direction.

  Also, the kth mask element for the 2n-1 expanded mask element, the k + 1th mask element for the 2n-1 expanded mask element, the kth mask element for the 2nth expanded mask element, and the 2nth It is preferable that the (k + 1) -th mask element for the stretched mask element is arranged in this order regardless of the value of k.

  Also, the kth mask element for the 2n-1 expanded mask element, the kth mask element for the 2n-1 expanded mask element, the k + 1th mask element for the 2n-1 expanded mask element, and the 2nth It is preferable that the (k + 1) -th mask element for the stretched mask element is arranged in this order regardless of the value of k.

  The seed crystal forming mask element group includes a first mask element having a first opening extending in the first direction and a second opening extending in the second direction, which are arranged along the moving direction. And a second mask element.

  The seed crystal forming mask element group includes a first forming mask element having one or more openings extending in the first direction and one opening extending in the second direction, which are arranged along the moving direction. And at least two second forming mask elements.

  Moreover, it is preferable that each opening of each mask element in the mask element group for seed crystal formation and each opening of each mask element in the mask element group for seed crystal extension are rectangular.

  Moreover, it is preferable that each opening of each mask element in the mask element group for seed crystal formation is circular, and each opening of each mask element in the mask element group for seed crystal extension is rectangular.

The second direction is preferably a direction perpendicular to the first direction.
Further, at least one of the two directions 1X + and 1Y +, the two directions 2X− and 2Y +, the two directions 3X− and 3Y−, and the two directions 4X + and 4Y−. It is preferable that an opening of the seed crystal stretching mask element group is disposed so as to simultaneously stretch the seed crystal in two directions.

  According to still another aspect of the present invention, a laser crystallization apparatus includes the mask, a laser beam irradiation apparatus that irradiates the laser beam, and a moving device that moves the object to be processed relative to the mask. And a control device for controlling irradiation and movement.

  In the laser crystallization apparatus, the amount of energy of the laser light emitted by the laser light irradiation device per time is an energy amount that melts the workpiece on the substrate in the thickness direction of the workpiece. preferable.

  In addition, the laser crystallization apparatus further includes a second laser beam irradiation device that irradiates the workpiece with a second laser beam different from the first laser beam when the laser beam is the first laser beam. In addition to the irradiation with the first laser beam, it is preferable that the region irradiated with the first laser beam is irradiated with the second laser beam.

  According to still another aspect of the present invention, a laser crystallization method is a laser crystallization method for forming crystal grains by irradiating an object to be moved with a laser beam through an opening. A seed crystal forming step for forming a seed crystal surrounded by a continuous crystal grain boundary or a partly discontinuous crystal grain boundary on an object to be processed, and X- For the Y orthogonal coordinate system, the X-axis positive direction is X +, the X-axis negative direction is X-, the Y-axis positive direction is Y +, the Y-axis negative direction is Y-, and the relative movement direction of the workpiece , X + includes a seed crystal extension step for extending the seed crystal to X +, X-, Y +, and Y-.

  In the seed crystal stretching step, it is preferable to perform the crystal stretching at Y + and Y− after the crystal stretching at X + and X− is completed.

  In the seed crystal stretching step, it is preferable to alternately perform crystal stretching in X + and X− and crystal stretching in Y + and Y−.

  In the seed crystal stretching step, it is preferable to simultaneously perform X + stretching and X- stretching.

  In the seed crystal forming step, at least two seed crystals are formed, and in the seed crystal stretching step, two crystals in the middle of stretching obtained by stretching the formed seed crystals in a predetermined direction, the predetermined direction It is preferable to simultaneously stretch two crystals adjacent to each other using one opening when performing the final stretching in a predetermined direction.

Moreover, it is preferable to repeat the seed crystal forming step, the seed crystal stretching step, and a moving step of moving the object to be processed in a direction perpendicular to the moving direction.

In the seed crystal stretching step, the first crystal in the middle of stretching obtained by stretching the formed seed crystal in the moving direction and the vertical direction and the second crystal in the middle of stretching adjacent to each other in the vertical direction. When the final extension in the vertical direction is performed, it is preferable to simultaneously extend the first crystal and the second crystal using one opening.

  According to still another aspect of the present invention, a laser crystallization method is a laser crystallization method for forming crystal grains by irradiating an object to be moved with a laser beam through an opening. A seed crystal forming step for forming a seed crystal surrounded by a continuous crystal grain boundary or a partly discontinuous crystal grain boundary on an object to be processed, and X- For the Y orthogonal coordinate system, the X-axis positive direction is X +, the X-axis negative direction is X-, the Y-axis positive direction is Y +, the Y-axis negative direction is Y-, and the relative movement direction of the workpiece Is X +, X + and Y + in the first quadrant in the coordinate system, X- and Y + in the second quadrant in the coordinate system, and X- and Y in the third quadrant in the coordinate system. In the fourth quadrant in the coordinate system, it expands to X + and Y-. And a seed crystal elongation step for.

  According to still another aspect of the present invention, the crystal material includes crystal grains formed by the laser crystallization method described above.

  According to still another aspect of the present invention, a semiconductor element includes a transistor having a channel region in crystal grains in the crystal material.

  By using the mask, the laser crystallization apparatus, and the laser crystallization method, a huge square crystal can be obtained as compared with the conventional case. Therefore, even if the TFT has a large channel size, the TFT characteristics do not deteriorate, and a high-performance TFT can be obtained as compared with the conventional TFT.

[Embodiment 1]
A laser beam irradiation apparatus according to an embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a diagram showing a schematic configuration of a laser crystallization apparatus 1.
As shown in the figure, the laser crystallization apparatus 1 includes a laser oscillator 10, a variable attenuator 11, a mirror 12, a mirror 13, an illumination optical element 14, a mask 15, an imaging lens 16, and a mirror. 17, a stage 18, and a control device 19. On the stage 18, a workpiece 20 to be irradiated with laser light is placed.

  Here, prior to the description of the members 10 to 19 of the laser crystallization apparatus 1, the workpiece 20 will be described. FIG. 2 is a cross-sectional view showing a cross section of the workpiece 20.

  The workpiece 20 includes a substrate 21, a base film 22 formed on the substrate 21, and an amorphous semiconductor thin film 23 formed on the base film 22.

  As the substrate 21, for example, a glass substrate or a quartz substrate can be used. Among these, a glass substrate is preferably used as the substrate 21 because it is inexpensive and a large-area substrate can be easily manufactured.

  The base film 22 is mainly used to prevent the substrate 21 from being affected by the heat of the melted amorphous semiconductor thin film 23 when the amorphous semiconductor thin film 23 is melted and crystallized by the laser beam. It is a membrane. By forming the base film 22, it is possible to prevent diffusion of impurities from the substrate 21 to the amorphous semiconductor thin film 23. As the base film 22, for example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or the like can be used. The base film 22 is formed to a thickness of, for example, 100 nm to 300 nm by, for example, vapor deposition, ion plating, sputtering, or the like.

  The amorphous semiconductor thin film 23 can be generated by, for example, plasma enhanced chemical vapor deposition (PECVD), vapor deposition, sputtering, or the like so that the film thickness becomes 10 nm to 100 nm. The amorphous semiconductor thin film 23 can be used without particular limitation as long as it exhibits semiconductor characteristics, but various characteristics are remarkably improved by increasing the length of crystal growth in the crystalline semiconductor film. It is preferable to use a crystalline silicon film. The material of the amorphous semiconductor thin film 23 is not limited to a material made of silicon, and a material mainly containing silicon containing other elements such as germanium can also be used.

Next, each member 10-19 of the laser crystallization apparatus 1 is demonstrated.
The laser light oscillator 10 emits pulsed laser light by pulse oscillation. The laser oscillator 10 is not particularly limited as long as it can irradiate a pulsed laser beam having a wavelength with a high absorption rate to the amorphous semiconductor thin film 23 in a solid state. However, it is preferable to be able to irradiate pulsed laser light having a wavelength in the ultraviolet region (1 nm to 400 nm). Further, the amount of energy per irradiation of the pulsed laser light emitted from the laser light oscillator 10 is set to be equal to or more than the amount of energy to be melted in the thickness direction of the solid state amorphous semiconductor thin film 23. For example, examples of the laser light emitted from the laser light oscillator 10 include XeCl excimer laser light having a wavelength of 308 nm.

  The variable attenuator 11 attenuates the power of the pulsed laser light emitted from the laser light oscillator 10 through absorption and scattering of the laser light. In particular, the variable attenuator 11 can change the amount of attenuation by an external signal or an adjustment knob. The pulse laser beam attenuated by the variable attenuator 11 is emitted toward the mirror 12.

  The mirror 12 reflects the pulsed laser light emitted from the variable attenuator 11 in the direction of the mirror 13.

  The mirror 13 reflects the pulsed laser light reflected by the mirror 12 in the direction of the illumination optical element 14.

  The illumination optical element 14 includes a homogenizer and a field lens (field lens). The illumination optical element shapes the pulsed laser light reflected by the mirror 13 into a desired dimension, and emits the shaped laser light in the direction of the mask 15 as a uniform intensity laser light.

  The mask 15 includes a slit (that is, an opening), and allows the pulse laser beam emitted from the illumination optical element 14 to pass through the slit. Details of the mask 15 will be described later.

  The imaging lens 16 forms an image on the mask 15 on the surface of the amorphous semiconductor thin film 23 at a magnification determined by the optical design of the laser crystallization apparatus 1. Therefore, the slit of the mask 15 and the image irradiated on the surface of the workpiece 20 are similar.

  The mirror 17 reflects the pulsed laser light emitted from the coupling lens 16 in the direction of the workpiece 20.

The stage 18 is movable in a predetermined direction.
The control device 19 controls the emission timing of the laser beam in the laser beam oscillator 10 and the position of the stage 18.

  As described above, in the laser crystallization apparatus 1, the laser light emitted from the laser light oscillator 10 passes through the variable attenuator 11, the illumination optical element 14, the mask 15, and the imaging lens 16 in this order. Then, the light is incident on the surface of the workpiece 20 placed on the stage 18.

  If the stage 18 moves to a predetermined position and the laser beam is irradiated at a predetermined timing, a method of irradiating the workpiece 20 with the laser beam while continuously moving the stage 18 may be adopted. Alternatively, a method of irradiating laser light while stepping and repeating the stage 18 may be adopted. In the following description, it is assumed that the workpiece 20 is irradiated with laser light while the stage 18 is continuously moved.

Here, details of the mask 15 will be described.
FIG. 3 is a diagram showing the configuration of a mask for forming a square crystal.

  As shown in the figure, the mask 15 includes a first mask element to an nth mask element (mask) in which a slit pattern (opening pattern) including a slit opening (slit width: SW) and a light shielding portion is formed. Element length: M) is provided in the order of the first mask element, the second mask element,..., The nth mask element (n = 14 in the example of FIG. 2). By irradiation of laser light from the first mask element through the nth mask element, the first irradiation pattern to the nth irradiation pattern are formed on the workpiece 20, respectively. The slit width SW is a value of about several μm to 10 μm, and the length M of each mask element is a value of about several hundred μm to 1 mm. The slit width (SW) in each mask element is constant. Moreover, the slit width in each mask element is also constant for the masks of other configurations in the present embodiment.

  The mask 15 includes a seed crystal forming mask element group for forming a seed crystal on the workpiece 20 and a seed crystal extending mask element group for extending the seed crystal. The seed crystal formation mask element group and the seed crystal extension mask element group are relative to the direction of relative movement of the mask with respect to the seed crystal formation mask element group (that is, the direction opposite to the direction of movement of the stage 18). Are arranged in this order.

  The seed crystal forming mask element group includes a seed crystal forming mask element 1-1 having a horizontally long (longitudinal movement direction of the mask) and a long (short relative movement direction of the mask). ) Of the seed crystal forming mask element 2-1 having a slit. In FIG. 3, the seed crystal formation mask element 1-1 and the seed crystal formation mask element 2-1 are arranged in this order, but this may be arranged in the reverse order.

  Here, the seed crystal forming mask group is a mask group for forming a seed crystal surrounded by a substantially closed-loop crystal grain boundary. That is, the seed crystal forming mask group is a mask group for forming a seed crystal that does not include a ridge therein. Furthermore, in other words, the mask group forms a seed crystal surrounded by a continuous crystal grain boundary or a crystal grain boundary partially discontinuous.

  In the following description, it is assumed that the laser crystallization apparatus 1 irradiates the pulse laser beam only once each time the mask 15 moves the distance M (that is, the length of the mask element).

  FIG. 4 shows laser irradiation (first irradiation) using the seed crystal formation mask element 1-1 and laser using the seed crystal formation mask element 2-1 after the mask 15 has moved a distance M. It is the figure which showed the XY orthogonal coordinate system which makes the origin the centroid P of the seed crystal 2AA formed by light irradiation (2nd irradiation). Here, a direction opposite to the direction of relative movement of the mask (that is, the direction of movement of the stage) is defined as a positive direction in the X-axis direction, and is perpendicular to the direction of relative movement of the mask 15 shown in FIG. The direction of the arrow (upward) is the positive direction in the Y-axis direction.

  Further, similarly to FIG. 107, as shown in FIG. 4, the positive direction (X-axis positive direction) in the X-axis direction in the k-th quadrant (k = 1, 2, 3, 4) in the XY orthogonal coordinate system is set. kX +, the negative direction in the X-axis direction (X-axis negative direction) is kX-, the positive direction in the Y-axis direction (Y-axis positive direction) is kY +, and the negative direction in the Y-axis direction (X-axis negative direction) ) As kY-. Further, 1X + and 4X + which are positive directions in the X-axis direction are collectively X +, 2X- and 3X- which are negative directions in the X-axis are collectively X-, and a positive direction in the Y-axis direction. 1Y + and 2Y + are collectively expressed as Y +, and 3Y− and 4Y− as negative directions in the Y-axis direction are collectively expressed as Y−.

  Further, as shown in the figure, X + indicating the positive direction in the X-axis direction and X- indicating the negative direction in the X-axis direction are collectively X, and Y + and Y indicating the positive direction in the Y-axis direction. Y- indicating the negative direction in the axial direction is collectively expressed as Y. That is, X indicates the direction of the X axis (including a positive direction and a negative direction), and Y indicates the direction of the Y axis (including a positive direction and a negative direction).

Here, returning to FIG. 3 again, the seed crystal stretching mask element group will be described.
As shown in FIG. 3, the seed crystal stretching mask element group includes a seed crystal stretching mask element 3-1, a seed crystal stretching mask element 3-2,... Mask element 3-j, seed crystal stretching mask element 4-1, seed crystal stretching mask element 4-2,..., Seed crystal stretching mask element 4-k. Further, the seed crystal stretching mask element group includes a seed crystal stretching mask element 5-1, a seed crystal stretching mask element 5-2,... , A seed crystal stretching mask element 6-1, a seed crystal stretching mask element 6-2,..., And a seed crystal stretching mask element 6-m. FIG. 3 shows an example in which j = k = l = m = 3.

  Then, the slit 3-1a of the seed crystal stretching mask element 3-1 and the slit of the mask 15 are shifted by δ from the slit 3-1a in the positive direction in the Y-axis direction of FIG. The slit 3-2a of the seed crystal stretching mask element 3-2 and the slit 3-3a of the seed crystal stretching mask 3-3 element constitute a slit group (hereinafter referred to as slit group 3-a). ing.

  Further, the slit 4-1a of the mask element 4-1 for seed crystal extension and the slit of the mask 15 are arranged by shifting the distance by δ with respect to the slit 4-1a in the negative direction in the Y-axis direction of FIG. The slit 4-2a of the seed crystal stretching mask element 4-2 and the slit 4-3a of the seed crystal stretching mask 4-3 element constitute a slit group (hereinafter referred to as slit group 4-a). Yes.

  Further, the mask 5-1a of the seed crystal stretching mask element 5-1 and the mask opposite to the direction of relative movement of the mask of FIG. 3 with respect to the slit 5-1a (positive direction in the X-axis direction). The slit 5-2a of the seed crystal stretching mask element 5-2 and the slit 5-3a of the seed crystal stretching mask 5-3 element, in which the 15 slits are arranged with the distance shifted by δ, are divided into slit groups (hereinafter, Slit group 5-a).

  Also, the slit 6-1a of the mask element 6-1 for seed crystal extension and the slit of the mask 15 in the mask relative movement direction (negative direction in the X-axis direction) of FIG. 3 with respect to the slit 6-1a. The slit 6-2a of the seed crystal stretching mask element 6-2 and the slit 6-3a of the seed crystal stretching mask 6-3 element, which are arranged by shifting the distance by δ, are divided into slit groups (hereinafter, slit group 6- 6). a).

  Here, the value of the distance δ is set to be smaller than a half value of the slit width SW.

  Hereinafter, the center line in the longitudinal direction (first direction) of the slit 1-1a of the seed crystal formation mask element 1-1 is defined as a first center line, and the slit 2- of the seed crystal formation mask element 2-1 is used. A center line in the longitudinal direction (second direction) of 1a is taken as a second center line.

  Further, the slit 3-1a of the seed crystal stretching mask element 3-1 moves the mask 15 relative to the negative direction in the X-axis direction of FIG. The slit 1-1a is arranged so as to overlap a part of the upper half (half on the positive direction side in the Y-axis direction) region on the positive direction side in the Y-axis direction. That is, the seed crystal stretching mask element 3-1 is partly formed with the slit 1-1 a of the seed crystal forming mask element 1-1 on the positive direction side in the Y-axis direction (one direction side in the second direction). A slit 3-1a is provided at the overlapping position.

  In addition, the slit 4-1a of the seed crystal stretching mask element 4-1 is a part of the upper half region of the slit 1-1a of the seed crystal forming mask element 1-1 and the negative direction side in the Y-axis direction. Are arranged so as to overlap each other. That is, the seed crystal stretching mask element 4-1 has the slit 4-1a at a position where a part thereof overlaps the first center line on the negative direction side in the Y-axis direction (the other direction side in the second direction). is doing.

  By arranging the slit 3-1a and the slit 4-1a as described above, the seed crystal formed in the upper half region of the slit 1-1a of the mask element 1-1 for seed crystal formation is used for seed crystal extension. It can be extended in the Y + direction by the slit 3-1a of the mask element 3-1, and can be extended to Y- by the slit 4-1a of the mask element 4-1 for seed crystal extension. That is, with the above arrangement, the seed crystal can be extended in the Y-axis direction (positive direction in the Y-axis direction and negative direction in the Y-axis direction).

  In the above example, the upper half region of the slit 1-1a of the seed crystal forming mask element 1-1 is extended as a seed crystal. However, the slit 3- 1a and the slit 4-1a of the seed crystal extension mask element 4-1 are arranged in the lower half of the slit 1-1a of the seed crystal formation mask 1-1 (half on the negative direction side in the Y-axis direction). It is possible to form a similar crystal even if they are overlapped.

  Further, the slit 5-1a of the seed crystal stretching mask element 5-1 moves the mask 15 relative to the negative direction in the X-axis direction of FIG. The slit 2-1a is arranged so as to overlap a part of the right half (half on the positive direction side in the X-axis direction) on the positive direction side in the X-axis direction. That is, part of the seed crystal stretching mask element 5-1 is partly on the slit 2-1a of the seed crystal forming mask element 2-1 on the positive direction side in the X-axis direction (one direction side in the first direction). A slit 5-1a is provided at the overlapping position.

  The slit 6-1a of the seed crystal stretching mask element 6-1 is a right half of the slit 2-1a of the seed crystal forming mask element 2-1 (half on the positive side in the X-axis direction). It arrange | positions so that it may overlap with a part in the negative direction side of a X-axis direction. That is, the seed crystal stretching mask element 6-1 has the slit 6-1a at a position where a part thereof overlaps the second center line on the negative direction side in the X-axis direction (the other direction side in the first direction). is doing.

  By arranging the slit 5-1a and the slit 6-1a as described above, for example, a crystal formed in the right half region of the slit 2-1a of the mask element 2-1 for seed crystal formation is seed crystal stretched. It can be extended to X + by the slit 5-1a of the mask element 5-1, and can be extended to X- by the slit 6-1a of the seed crystal extension mask element 6-1.

  As described above, the mask 15 has a slit, and is a mask for irradiating an object to be processed that relatively moves laser light through the slit. In addition, the mask 15 includes a seed crystal forming mask element 1-1 having a slit 1-1a arranged in the direction of movement and extending in the X-axis direction (first direction), and the Y-axis direction (second A seed crystal forming mask element group including a seed crystal forming mask element 1-1 having a slit 2-1a extending in a direction).

  Further, the mask 15 is for extending the seed crystal having the slit 3-1a arranged along the direction of the movement following the mask element 1-1 for seed crystal formation and the mask element 1-1 for seed crystal formation. Mask element 3-1, seed crystal stretching mask element having slit 4-1a, seed crystal stretching mask element 5-1 having slit 5-1a, and seed crystal stretching mask element having slit 6-1a 6-1 and a mask element group for extending a seed crystal.

  Further, as described above, the center line in the X-axis direction (first direction) of the slit 1-1a is the first center line, and the center line in the Y-axis direction (second direction) of the slit 2-1a is the second center. In the case of a line, in the mask 15, a part of the slit 3-1a overlaps with the slit 1-1a on one side in the Y-axis direction, and a part of the slit 4-1a is on the other side in the Y-axis direction. And the slit 5-1a partially overlaps the slit 2-1a on one side in the X-axis direction, and part of the slit 6-1a extends in the other direction in the X-axis direction. It is the structure which overlaps with the said 2nd centerline in the side.

  Here, the seed crystal extension mask element 3-1 is extended to the first extension mask element, the seed crystal extension mask element 3-2 to the fifth extension mask element, and the seed crystal extension mask element 3-3 to the ninth extension. As a mask element, a mask element that extends the seed crystal in the Y + direction can be expressed as a fourth n-3 extended mask element, where n is a natural number of 1 or more. Similarly, the seed crystal extension mask element 4-1 is extended to the second extension mask element, the seed crystal extension mask element 4-2 is extended to the sixth extension mask element, and the seed crystal extension mask element 4-3 is extended to the tenth extension. As a mask element, the mask element that extends the seed crystal in the Y-direction can be expressed as a fourth n-2 extended mask element, where n is a natural number of 1 or more.

  Further, when the slit 3-1a is the first extension slit, the slit 3-2a is the fifth extension slit, and the slit 3-3a is the ninth extension slit, the slit of the mask element that extends the seed crystal in the Y + direction is as follows. , N is a natural number of 1 or more, and can be expressed as a fourth n-3 extension slit. Similarly, when the slit 4-1a is the second extension slit, the slit 4-2a is the sixth extension slit, and the slit 4-3a is the tenth extension slit, the mask element for extending the seed crystal in the Y-direction is used. The slit can be expressed as a 4n-2 extension slit, where n is a natural number of 1 or more.

  Further, the seed crystal stretching mask element 5-1 is the third stretching mask element, the seed crystal stretching mask element 5-2 is the seventh stretching mask element, and the seed crystal stretching mask element 5-3 is the eleventh stretching mask. As an element, a mask element that extends the seed crystal in the X + direction can be expressed as a fourth n-1 extended mask element, where n is a natural number of 1 or more. Similarly, the seed crystal extension mask element 6-1 is extended to the fourth extension mask element, the seed crystal extension mask element 6-2 is extended to the eighth extension mask element, and the seed crystal extension mask element 6-3 is extended to the twelfth extension. As a mask element, a mask element that extends the seed crystal in the X-direction can be expressed as a fourth n extended mask element, where n is a natural number of 1 or more.

  Further, when the slit 5-1a is the third extension slit, the slit 5-2a is the seventh extension slit, and the slit 5-3a is the eleventh extension slit, the slit of the mask element that extends the seed crystal in the X + direction is as follows. , N is a natural number of 1 or more, and can be expressed as a 4n-1 extension slit. Similarly, when the slit 6-1a is the fourth extension slit, the slit 6-2a is the eighth extension slit, and the slit 6-3a is the twelfth extension slit, the mask element for extending the seed crystal in the X-direction is used. The slit can be expressed as a fourth n extension slit, where n is a natural number of 1 or more.

  The mask 15 is a seed crystal forming mask having a slit pattern for forming a seed crystal surrounded by a continuous crystal grain boundary or a crystal grain boundary partially discontinuous on the workpiece 20. When the relative movement direction of the workpiece 20 in the XY orthogonal coordinate system with the element group and the specific position P of the seed crystal as the origin is the positive direction in the X-axis direction, the seed crystal Seed crystal stretching mask element having a slit pattern for stretching in a positive axial direction, a negative X-axis direction, a positive Y-axis direction, and a negative Y-axis direction It is also a structure provided with a group.

  Further, the mask 15 is arranged so that the seed crystal is in a positive direction in the X-axis direction and a positive direction in the Y-axis direction in the first quadrant in the coordinate system, and in the X-axis direction in the second quadrant in the coordinate system. In the negative direction and the positive direction in the Y-axis direction, in the third quadrant in the coordinate system, in the negative direction in the X-axis direction and in the negative direction in the Y-axis direction, in the fourth quadrant in the coordinate system. Is also configured to include a seed crystal stretching mask element group having a slit pattern for stretching in a positive direction in the X-axis direction and a negative direction in the Y-axis direction.

  In the above example, the right half region of the slit 2-1a of the seed crystal formation mask element 2-1 is extended as a seed crystal. However, the slit 5- of the seed crystal extension mask element 5-1 is shown. A similar crystal is formed even if 1a and the slit 6-1a of the seed crystal stretching mask element 6-1 are overlapped with the left half region of the slit 2-1a of the seed crystal forming mask element 2-1. It is possible. In addition, a larger square crystal can be formed by making the overlapping region as small as possible.

  With the laser crystallization apparatus 1 having the above-described configuration, pulsed laser light from the laser light oscillator 10 is converted into a variable attenuator 11, a mirror 12, a mirror 13, an illumination optical element 14, a mask 15, and an image. The irradiated area of the amorphous semiconductor thin film 23 is melted in the thickness direction at each position where the surface of the workpiece 20 is irradiated through the lens 16 and the mirror 17 and the slit is projected.

  After the irradiation with the pulse laser beam is completed, the melted amorphous semiconductor thin film 23 begins to solidify, and the crystal grows laterally from the end of the region irradiated with the laser beam through the slit toward the center. . That is, crystal growth occurs from a region corresponding to the end of the slit in a direction perpendicular to the direction of relative movement of the mask (Y-axis direction) toward a region corresponding to the center of the slit.

  Thereafter, the control device 19 controls the laser light oscillator 10 and the stage 18 to move the mask 15 relative to the workpiece 20 by the mask length M in the X− (negative direction in the X-axis direction). Then, the laser beam oscillator 10 irradiates the laser beam again.

  By repeating such laser light irradiation and movement of the workpiece 20, the seed crystal mask element 2 is formed on the region crystallized through the slit 1-1a of the seed crystal forming mask element 1-1. -1 through the slit 2-1a, crystallization through the slit 3-1a of the seed crystal stretching mask element 3-1 (stretching),..., Slit of the seed crystal stretching mask element 6-3 Crystallization is performed through the slits of the adjacent mask, such as crystallization (extension) through 6-3a.

  Hereinafter, a process of forming a seed crystal and a process of extending the formed seed crystal using the mask 15 shown in FIG. 3 will be described with reference to FIGS. More specifically, FIG. 5 to FIG. 18 show the crystal formation process for the region crystallized through the slit 1-1a of the seed crystal formation mask element 1-1 by the first irradiation (first irradiation). This will be explained based on.

  Hereinafter, the region on the workpiece 20 corresponding to the seed crystal formation mask element 1-1 when the first irradiation is performed using the slit 1-1a is referred to as a corresponding region. More specifically, the slit 1-1a (opening) and the light shielding portion of the seed crystal formation mask element 1-1 excluding the slit 1-1a (that is, the entire seed crystal formation mask element 1-1). A region projected in parallel on the surface of the workpiece 20 is referred to as a corresponding region.

  Further, hereinafter, the irradiation of the laser light sequentially irradiated on the corresponding area following the first irradiation will be referred to as second irradiation, third irradiation,..., 14th irradiation.

  In FIGS. 5 to 18, the region surrounded by the thin line indicates the region that is crystallized by each irradiation, and the region surrounded by the dotted line is crystallized by the irradiation one time before each irradiation. A region surrounded by a thick line indicates a crystal that is crystallized by the irradiation, and a hatched region indicates a crystal formed by irradiation one time before each irradiation.

  FIG. 5 is a top view of the workpiece 20 when crystallization is performed by the first irradiation using the slit 1-1a of the seed crystal formation mask element 1-1.

  In the corresponding region, as shown in FIG. 5, the crystal 1-1A is formed by the slit 1-1a of the seed crystal forming mask element 1-1. Here, the crystal 1AA in FIG. 5 is a part of the crystal 1-1A formed by the first irradiation, and is an elongated needle-like crystal.

  FIG. 6 is a top view of the workpiece 20 when crystallization is performed by the second irradiation using the slit 2-1a of the seed crystal formation mask element 2-1.

  By this second irradiation, as shown in FIG. 6, a crystal 2-1A is formed in the corresponding region. At this time, a needle-like crystal formed by the first irradiation is formed. Further, in a region where the crystal 2-1A and the crystal 1-1A formed by the first irradiation intersect, the acicular crystal 1AA is stretched to X-, and a square seed crystal 2AA is formed. Here, the seed crystal 2AA is a crystal surrounded by a substantially closed-loop crystal grain boundary (ridge), and does not include a crystal grain boundary therein. The seed crystal is stretched by subsequent laser light irradiation (third irradiation to fourteenth irradiation).

  FIG. 7 is a top view of the workpiece 20 when crystallization is performed by third irradiation using the slit 3-1a of the seed crystal stretching mask element 3-1. FIG. 8 is a top view of the workpiece 20 when crystallization is performed by the fourth irradiation using the slit 3-2a of the mask element 3-2 for extending the seed crystal. FIG. 9 is a top view of the workpiece 20 when crystallization is performed by the fifth irradiation using the slit 3-3a of the mask element 3-3 for seed crystal extension.

  By the third irradiation, as shown in FIG. 7, a crystal 3-1A is formed in the corresponding region. In addition, by this third irradiation, as shown in the figure, the seed crystal 2AA is expanded to Y +, and as a result, a crystal 3AA is formed. As shown in the figure, the centroid of the crystal 2AA is the origin P of the XY coordinate system. Thereafter, as shown in FIG. 8, crystals 3-2A are formed in the corresponding region by the fourth irradiation. Further, by this fourth irradiation, as shown in the figure, the crystal 3AA is expanded to Y +, and as a result, the crystal 4AA is formed. Further, by the fifth irradiation, as shown in FIG. 9, a crystal 3-3A is formed in the corresponding region. In addition, by the fifth irradiation, as shown in the figure, the crystal 4AA is expanded to Y +, and as a result, the crystal 5AA is formed.

  FIG. 10 is a top view of the workpiece 20 when crystallization is performed by sixth irradiation using the slit 4-1a of the seed crystal stretching mask element 4-1. FIG. 11 is a top view of the workpiece 20 when crystallization is performed by seventh irradiation using the slit 4-2a of the seed crystal stretching mask element 4-2. FIG. 12 is a top view of the workpiece 20 when crystallization is performed by the eighth irradiation using the slit 4-3a of the seed crystal stretching mask element 4-3.

  As a result of the sixth irradiation, a crystal 4-1A is formed in the corresponding region as shown in FIG. Further, by this sixth irradiation, the crystal 5AA is stretched to Y- as shown in the figure, and as a result, the crystal 6AA is formed. Thereafter, as a result of the seventh irradiation, a crystal 4-2A is formed in the corresponding region as shown in FIG. In addition, by the seventh irradiation, as shown in the figure, the crystal 6AA is expanded to Y-, and as a result, the crystal 7AA is formed. Thereafter, the crystal 4-3A is formed in the corresponding region by the eighth irradiation. Further, by the eighth irradiation, as shown in the figure, the crystal 7AA is expanded to Y-, and as a result, the crystal 8AA is formed.

  FIG. 13 is a top view of the workpiece 20 when crystallization is performed by the ninth irradiation using the slit 5-1a of the seed crystal stretching mask element 5-1. FIG. 14 is a top view of the workpiece 20 when crystallization is performed by the tenth irradiation using the slit 5-2a of the seed crystal stretching mask element 5-2. FIG. 15 is a top view of the workpiece 20 when crystallization is performed by the eleventh irradiation using the slit 5-3a of the seed crystal stretching mask element 5-3.

  As a result of the ninth irradiation, a crystal 5-1A is formed in the corresponding region as shown in FIG. In addition, by the ninth irradiation, the seed crystal 8AA is expanded to X + as shown in the figure, and as a result, the crystal 9AA is formed. Thereafter, as a result of the tenth irradiation, a crystal 5-2A is formed in the corresponding region as shown in FIG. In addition, by the tenth irradiation, the crystal 9AA is expanded to X + as shown in the figure, and as a result, the crystal 10AA is formed. Further, as a result of the eleventh irradiation, a crystal 5-3A is formed in the corresponding region as shown in FIG. In addition, as a result of the eleventh irradiation, the crystal 10AA is expanded to X + as shown in the figure, and as a result, the crystal 11AA is formed.

  FIG. 16 is a top view of the workpiece 20 when crystallization is performed by twelfth irradiation using the slit 6-1a of the seed crystal stretching mask element 6-1. FIG. 17 is a top view of the workpiece 20 when crystallization is performed by thirteenth irradiation using the slit 6-2a of the seed crystal stretching mask element 6-2. FIG. 18 is a top view of the workpiece 20 when crystallization is performed by the 14th irradiation using the slit 6-3a of the mask element 6-3 for extending the seed crystal.

  As a result of the twelfth irradiation, a crystal 6-1A is formed in the corresponding region as shown in FIG. In addition, as a result of the twelfth irradiation, the seed crystal 11AA is expanded to X- as shown in the figure, and as a result, the crystal 12AA is formed. Thereafter, by the thirteenth irradiation, a crystal 6-2A is formed in the corresponding region as shown in FIG. In addition, as a result of the thirteenth irradiation, the crystal 12AA is expanded to X− as shown in the figure, and as a result, the crystal 13AA is formed. Thereafter, the 14th irradiation forms crystals 6-3A in the corresponding region as shown in FIG. In addition, as a result of the fourteenth irradiation, the crystal 13AA is expanded to X- as shown in the figure, and as a result, the crystal 14AA is formed.

Thus, crystallization is completed.
Thus, in the mask 15, the seed crystal stretching mask element group 3-2 having the slits 3-2 a arranged at least along the above-described direction of movement of the mask. A seed crystal stretching mask element 4-2 having a slit 4-2a, a seed crystal stretching mask element 5-2 having a slit 5-2a, and a seed crystal stretching mask element 6-6 having a slit 6-2a. 2 is provided.

  Here, the center line in the X-axis direction (first direction) of the slit 3-1a described above is the third center line, the center line in the X-axis direction of the slit 4-1a is the fourth center line, and the slit 5-1a. The center line in the Y-axis direction (second direction) is the fifth center line, and the center line in the Y-axis direction of the slit 6-1a is the sixth center line.

  When each center line is defined in this way, the seed crystal stretching mask element 3-2 is different from the seed crystal stretching mask element 3-1, in the seed crystal forming mask element 1-1 and the seed crystal forming mask element 2-. 1 and a part of the slit 3-2a overlaps the third center line on the one direction side in the Y-axis direction. The seed crystal extension mask element 4-2 is arranged on the opposite side of the seed crystal formation mask element 1-1 and the seed crystal formation mask element 2-1 with respect to the seed crystal extension mask element 4-1. In addition, a part of the slit 4-2a overlaps the fourth center line on the other direction side in the Y-axis direction. Further, the seed crystal extension mask element 5-2 is arranged on the opposite side of the seed crystal formation mask element 1-1 and the seed crystal formation mask element 2-1 with respect to the seed crystal extension mask element 5-1. In addition, a part of the slit 5-2a overlaps the fifth center line on the one direction side in the X-axis direction. The seed crystal extension mask element 6-2 is arranged on the opposite side of the seed crystal formation mask element 1-1 and the seed crystal formation mask element 2-1 with respect to the seed crystal extension mask element 6-1. In addition, a part of the slit 6-2a overlaps the sixth center line on the other direction side in the X-axis direction.

  FIG. 19 is a diagram showing the relationship between the seed crystal and the finally formed square crystal. When the definition of the direction shown in FIG. 4 is used, in the laser crystallization apparatus 1, after the seed crystal is formed by the first irradiation and the second irradiation, the seed crystal is expanded to Y + by the third irradiation to the fifth irradiation. The seed crystal is expanded to Y- by the sixth irradiation to the eighth irradiation, the seed crystal is expanded to X + by the ninth irradiation to the eleventh irradiation, and the seed crystal is expanded to X- by the twelfth irradiation to the fourteenth irradiation. . Thus, by using the laser crystallization apparatus 1, the seed crystal can be extended in all quadrants of the first quadrant to the fourth quadrant. In this respect, the crystal formed using the laser crystallization apparatus 1 is different from the crystal formed by the conventional laser crystallization method (Patent Document 2).

  As described above, the mask 15 has a configuration in which the slits of the seed crystal formation mask element group are arranged so that the seed crystal surrounded by the substantially closed-loop crystal grain boundary is formed by the laser light irradiation. By the control of the irradiation timing of the laser light irradiated through the mask element group for extending the seed crystal following the mask element group for forming the seed crystal and the above-described movement control, it is surrounded by the formed substantially closed-loop crystal grain boundary. The slit of the mask element group for seed crystal extension is arranged so that the seed crystal extends in each direction of 1X +, 1Y +, 2X−, 2Y +, 3X−, 3Y−, 4X +, and 4Y−. It can be said that there is.

  Further, the laser crystallization method by the laser crystallization apparatus 1 is an orthogonal coordinate system having the centroid P of the seed crystal as the origin when the seed crystal formed by the first irradiation and the second irradiation is expanded by the subsequent irradiation. Is a laser crystallization method in which the seed crystal is extended in the X-axis direction (X + or X-) and the Y-axis direction (Y + or Y-), respectively, in all quadrants (first quadrant to fourth quadrant).

  More specifically, the laser crystallization method includes 1X + and 1Y + in the first quadrant, 2X− and 2Y + in the second quadrant, 3X− and 3Y− in the third quadrant, and the fourth quadrant. In this method, the seed crystal is extended to 4X + and 4Y−. Therefore, the crystal can be grown in all eight directions in which the seed crystal can be stretched.

  In other words, according to the laser crystallization method by the laser crystallization apparatus 1, the positive direction in the X-axis direction, the negative direction in the X-axis direction, the positive direction in the Y-axis direction, and the negative direction in the Y-axis direction In addition, a seed crystal can be grown.

  As described above, the laser crystallization apparatus 1 can obtain a large square crystal as compared with the prior art without using a wide slit.

  By the way, when the channel size of the TFT is smaller than that of the square crystal, it is possible to obtain a high-performance TFT by arranging the channel so as to be accommodated in the square crystal as compared with the case where the channel is not arranged in this way. it can. However, in the case where the channel size is larger than that of the square crystal, the region other than the square crystal in the channel is composed of a non-crystallized film (amorphous semiconductor film). For this reason, when the channel size is larger than that of the square crystal, the TFT characteristics are lowered.

  However, since the laser crystallization apparatus 1 can form a larger square crystal as compared with the prior art, the TFT characteristics do not deteriorate even when the TFT has a large channel size. Therefore, a high-performance TFT can be obtained as compared with the conventional TFT.

<Modification Example of Mask Configuration-1>
By the way, in the above description, an example was described in which the extension to Y +, the extension to Y-, the extension to X +, and the extension to X- were completed in this order, whereby a square crystal was obtained. . However, the present invention is not limited to this, and the stretching in the other direction may be performed before the stretching in one direction is completed.

  Therefore, in the following, as an example, a laser crystallization method in which extension to Y + and extension to Y− are alternately repeated, and then extension to X + and extension to X− is repeated will be described with reference to FIGS. Based on

FIG. 20 is a diagram showing a configuration of a mask for forming a square crystal.
The mask 15a shown in the figure is different from the seed crystal extension mask elements in the mask 15 shown in FIG. 3 in the arrangement of the seed crystal extension mask elements. Other than that, the mask 15a shown in FIG. 20 is the same as the mask 15 shown in FIG. In FIG. 20, the same reference numerals are assigned to the same mask elements as the seed crystal stretching mask elements of the mask 15 shown in FIG.

  Hereinafter, a process of forming a seed crystal and a process of extending the formed seed crystal using the mask 15a shown in FIG. 20 will be described with reference to FIGS. In FIGS. 21 to 34, the region surrounded by the thin line indicates the region that is crystallized by each irradiation, and the region surrounded by the dotted line is crystallized by the irradiation one time before each irradiation. A region surrounded by a thick line indicates a crystal that is crystallized by the irradiation, and a hatched region indicates a crystal formed by irradiation one time before each irradiation.

  FIG. 21 is a top view of the workpiece 20 when crystallization is performed by the first irradiation using the slit 1-1a of the seed crystal formation mask element 1-1.

  In the corresponding region, as shown in FIG. 21, a crystal 1-1A is formed by the slit 1-1a of the seed crystal forming mask element 1-1. Here, the crystal 1AA in FIG. 21 is a part of the crystal 1-1A formed by the first irradiation, and is an elongated needle-like crystal.

  FIG. 22 is a top view of the workpiece 20 when crystallization is performed by the second irradiation using the slit 2-1a of the seed crystal formation mask element 2-1.

  By this second irradiation, as shown in FIG. 22, a crystal 2-1A is formed in the corresponding region. At this time, a needle-like crystal formed by the first irradiation is formed. Further, in a region where the crystal 2-1A and the crystal 1-1A formed by the first irradiation intersect, the acicular crystal 1AA is stretched to X-, and a square seed crystal 2AA is formed. Here, the seed crystal 2AA is a crystal surrounded by a substantially closed-loop crystal grain boundary (ridge), and does not include a crystal grain boundary therein. The seed crystal is stretched by subsequent laser light irradiation (third irradiation to fourteenth irradiation).

  FIG. 23 is a top view of the workpiece 20 when crystallization is performed by the third irradiation using the slit 3-1a of the seed crystal stretching mask element 3-1. FIG. 24 is a top view of the workpiece 20 in the case where crystallization is performed by the fourth irradiation using the slit 4-1a of the seed crystal stretching mask element 4-1.

  By the third irradiation, a crystal 3-1A is formed in the corresponding region as shown in FIG. In addition, by this third irradiation, as shown in the figure, the seed crystal 2AA is expanded to Y +, and as a result, a crystal 3AA is formed. Thereafter, the fourth irradiation forms crystals 4-1A in the corresponding region as shown in FIG. In addition, the fourth irradiation causes the crystal 3AA to expand to Y- as shown in the figure, and as a result, the crystal 4AA is formed.

  FIG. 25 is a top view of the workpiece 20 when crystallization is performed by the fifth irradiation using the slit 3-2a of the mask element 3-2 for seed crystal extension. FIG. 26 is a top view of the workpiece 20 when crystallization is performed by sixth irradiation using the slit 4-2a of the seed crystal stretching mask element 4-2.

  As a result of the fifth irradiation, a crystal 3-2A is formed in the corresponding region as shown in FIG. In addition, by the fifth irradiation, as shown in the figure, the crystal 4AA is expanded to Y +, and as a result, the crystal 5AA is formed. Thereafter, the sixth irradiation forms crystals 4-2A in the corresponding region as shown in FIG. Further, by this sixth irradiation, the crystal 5AA is stretched to Y- as shown in the figure, and as a result, the crystal 6AA is formed.

  FIG. 27 is a top view of the workpiece 20 when crystallization is performed by seventh irradiation using the slit 3-3a of the seed crystal stretching mask element 3-3. FIG. 28 is a top view of the workpiece 20 when crystallization is performed by the eighth irradiation using the slit 4-3a of the mask element 4-3 for extending the seed crystal.

  By the seventh irradiation, a crystal 4-2A is formed in the corresponding region as shown in FIG. In addition, by the seventh irradiation, as shown in the figure, the crystal 6AA is expanded to Y +, and as a result, the crystal 7AA is formed. Thereafter, as a result of the eighth irradiation, a crystal 4-3A is formed in the corresponding region as shown in FIG. Further, by the eighth irradiation, as shown in the figure, the crystal 7AA is expanded to Y-, and as a result, the crystal 8AA is formed.

  FIG. 29 is a top view of the workpiece 20 when crystallization is performed by the ninth irradiation using the slit 5-1a of the mask element 5-1 for crystal growth. FIG. 30 is a top view of the workpiece 20 when crystallization is performed by the tenth irradiation using the slit 6-1a of the mask element 6-1 for seed crystal extension.

  As a result of the ninth irradiation, a crystal 5-1A is formed in the corresponding region as shown in FIG. In addition, by the ninth irradiation, the seed crystal 8AA is expanded to X + as shown in the figure, and as a result, the crystal 9AA is formed. Thereafter, as a result of the tenth irradiation, a crystal 6-1A is formed in the corresponding region as shown in FIG. Further, by the tenth irradiation, the crystal 9AA is expanded to X− as shown in the figure, and as a result, the crystal 10AA is formed.

  FIG. 31 is a top view of the workpiece 20 when crystallization is performed by eleventh irradiation using the slit 5-2a of the seed crystal stretching mask element 5-2. FIG. 32 is a top view of the workpiece 20 when crystallization is performed by the twelfth irradiation using the slit 6-2a of the seed crystal stretching mask element 6-2.

  As a result of the eleventh irradiation, a crystal 5-2A is formed in the corresponding region as shown in FIG. In addition, as a result of the eleventh irradiation, the crystal 10AA is expanded to X + as shown in the figure, and as a result, the crystal 11AA is formed. Thereafter, by the twelfth irradiation, as shown in FIG. 32, a crystal 6-2A is formed in the corresponding region. In addition, as a result of the twelfth irradiation, the seed crystal 11AA is expanded to X- as shown in the figure, and as a result, the crystal 12AA is formed.

  FIG. 33 is a top view of the workpiece 20 when crystallization is performed by the thirteenth irradiation using the slit 5-3a of the seed crystal stretching mask element 5-3. FIG. 34 is a top view of the workpiece 20 when crystallization is performed by the 14th irradiation using the slit 6-3a of the mask element 6-3 for seed crystal extension.

  As a result of the thirteenth irradiation, a crystal 5-3A is formed in the corresponding region as shown in FIG. Further, by this thirteenth irradiation, as shown in the figure, the crystal 12AA is expanded to X +, and as a result, the crystal 13AA is formed. Thereafter, the 14th irradiation forms crystals 6-3A in the corresponding region as shown in FIG. In addition, as a result of the fourteenth irradiation, the crystal 13AA is expanded to X- as shown in the figure, and as a result, the crystal 14AA is formed.

Thus, crystallization is completed.
As described above, when the mask 15a shown in FIG. 20 is used, the order of crystal growth is different from the case where the mask 15 shown in FIG. 3 is used, and the mask 15 shown in FIG. 3 is used. Square crystals of the same size as sometimes can be formed.

<Mask configuration change example-2>
Next, a configuration in which the extension to Y + and the extension to Y− are simultaneously performed, and the extension to X + and the extension to X− are simultaneously performed will be described with reference to FIGS.

  FIG. 35 is a diagram showing a configuration of a mask for forming a square crystal. The mask 15b shown in the figure has the slit for extending to Y + and the slit for extending to Y- being arranged in the same mask element, and the slit for extending to X + and the slit to extend to X- are the same mask. Placed in the element.

  The mask element 11-1 and the mask element 12-1 serve as seed crystal forming mask elements. The other six mask elements (13-1 to 13-3 and 15-1 to 15-3) serve as seed crystal stretching mask elements. Here, in the mask element for seed crystal extension, each mask element has two slits.

  Specifically, the seed crystal forming mask element 11-1 includes a slit 11-1a, and the seed crystal forming mask element 12-1 includes a slit 12-1a. The seed crystal stretching mask 13-1 includes a slit 13-1a and a slit 14-1a, and the seed crystal stretching mask 13-2 includes a slit 13-2a and a slit 14-2a. -3 includes a slit 13-3a and a slit 14-3a. Further, the seed crystal stretching mask element 15-1 includes a slit 15-1a and a slit 16-1a, and the seed crystal stretching mask element 15-2 includes a slit 15-2a and a slit 16-2a. The mask element 15-3 includes a slit 15-3a and a slit 16-3a.

  Here, the seed crystal extension mask element 13-1 is the first extension mask element, the seed crystal extension mask element 13-2 is the third extension mask element, and the seed crystal extension mask element 13-3 is the fifth extension mask element. Then, the mask element that extends the seed crystal in the Y + direction and the Y− direction can be expressed as a second n−1 extended mask element where n is a natural number of 1 or more.

  Further, when the slit 13-1a is a first A extension slit, the slit 3-2a is a third A extension slit, and the slit 13-3a is a fifth A extension slit, the seed crystal is extended in the Y + direction. The slit of the mask element can be expressed as a 2n-1th A extension slit, where n is a natural number of 1 or more. Similarly, if the slit 14-1a is the first B extension slit, the slit 14-2a is the third B extension slit, and the slit 14-3a is the fifth B extension slit, the seed crystal is aligned in the Y-direction. The slit of the mask element to be extended can be expressed as a 2n-1th B extension slit, where n is a natural number of 1 or more.

  The seed crystal stretching mask element 15-1 is a second stretching mask element, the seed crystal stretching mask element 15-2 is a fourth stretching mask element, and the seed crystal stretching mask element 15-3 is a sixth stretching mask element. Then, the mask element that extends the seed crystal in the X + direction and the X-direction can be expressed as a second n extended mask element, where n is a natural number of 1 or more.

  Further, when the slit 15-1a is the second A extension slit, the slit 15-2a is the fourth A extension slit, and the slit 15-3a is the sixth A extension slit, the seed crystal is extended in the X + direction. The slit of the mask element can be expressed as a 2nth A extension slit, where n is a natural number of 1 or more. Similarly, if the slit 16-1a is the second B extension slit, the slit 16-2a is the fourth B extension slit, and the slit 16-3a is the sixth B extension slit, the seed crystal is aligned in the X-direction. The slit of the mask element to be extended can be expressed as a 2nth B extension slit, where n is a natural number of 1 or more.

  Incidentally, as shown in FIG. 35, the position of each slit in each mask element has the following relationship with the mask 15 in FIG. 3 or the mask 15a in FIG.

  First, the slit 11-1a is provided at the same position as the slit 1-1a, and the slit 12-1a is provided at the same position as the slit 2-1a. Further, the slit 13-1a is provided at the same position as the slit 3-1a, the slit 13-2a is provided at the same position as the slit 3-2a, and the slit 13-3a is provided at the same position as the slit 3-3a. Further, the slit 14-1a is provided at the same position as the slit 4-1a, the slit 14-2a is provided at the same position as the slit 4-2a, and the slit 14-3a is provided at the same position as the slit 4-3a.

  The slit 15-1a is provided at the same position as the slit 5-1a, the slit 15-2a is provided at the same position as the slit 5-2a, and the slit 15-3a is provided at the same position as the slit 5-3a. Further, the slit 16-1a is provided at the same position as the slit 6-1a, the slit 16-2a is provided at the same position as the slit 6-2a, and the slit 16-3a is provided at the same position as the slit 6-3a.

  As described above, the mask 15b has the slits 13 arranged at least along the direction of movement of the mask described above, following the seed crystal formation mask element 11-1 and the seed crystal formation mask element 12-1. -1a and a seed crystal stretching mask element 13-1 having a slit 14-1a and a seed crystal stretching mask element 15-1 having a slit 15-1a and a slit 16-1a It is the structure provided with a group.

  Here, the center line in the X-axis direction (first direction) of the slit 11-1a (first slit) is the first center line, and the Y-axis direction (second direction) of the slit 12-1a (second slit). The center line is defined as the second center line.

  When each center line is defined in this way, the mask 15b has a portion of the slit 13-1a overlapping the slit 11-1a on one side in the Y-axis direction, and a portion of the slit 14-1a is It is the structure which overlaps with the said 1st centerline in the other direction side of an axial direction. Further, in the mask 15b, a part of the slit 15-1a overlaps the slit 12-1a on one side in the X-axis direction, and a part of the slit 16-1a is on the other side in the X-axis direction. It is the structure which overlaps with the said 2nd centerline.

  Further, in the mask 15b, the seed crystal stretching mask element group further includes a seed crystal stretching mask element 13-2 having a slit 13-2a and a slit 14-2a arranged along the direction of movement. , And a seed crystal stretching mask element 15-2 having a slit 15-2a and a slit 16-2a.

  Here, the center line in the X-axis direction (first direction) of the slit 13-1a is the third A center line, the center line in the X-axis direction of the slit 14-1a is the third B center line, and the Y of the slit 15-1a. The center line in the axial direction is defined as the 4A center line, and the center line in the Y axis direction of the slit 16-1a is defined as the 4B center line.

  When each center line is defined in this way, the mask 15b has a part of the slit 13-2a that overlaps the third A center line on the one direction side in the Y-axis direction and a part of the slit 14-2a. , And the third B center line on the other direction side in the Y-axis direction. Further, in the mask 15b, a part of the slit 15-2a overlaps the fourth A center line on the one direction side in the X-axis direction, and a part of the slit 16-2a is in the other direction in the X-axis direction. It is the structure which overlaps with the said 4B centerline in the direction side.

  In the following, a process of forming a seed crystal and a process of extending the formed seed crystal using the mask 15b shown in FIG. 35 will be described with reference to FIGS. In FIGS. 36 to 43, the region surrounded by the thin line indicates the region that is crystallized by each irradiation, and the region surrounded by the dotted line is crystallized by the irradiation one time before each irradiation. A region surrounded by a thick line indicates a crystal that is crystallized by the irradiation, and a hatched region indicates a crystal formed by irradiation one time before each irradiation.

  FIG. 36 is a top view of the workpiece 20 when crystallization is performed by the first irradiation using the slit 11-1a of the seed crystal forming mask element 11-1.

  In the corresponding region, as shown in FIG. 36, the crystal 11-1A is formed by the slit 11-1a of the seed crystal forming mask element 11-1. Here, the crystal 1AA in FIG. 36 is a part of the crystal 11-1A formed by the first irradiation, and is an elongated needle-like crystal.

  FIG. 37 is a top view of the workpiece 20 when crystallization is performed by the second irradiation using the slit 12-1a of the seed crystal forming mask element 12-1.

  By this second irradiation, crystals 12-1A are formed in the corresponding region as shown in FIG. At this time, a needle-like crystal formed by the first irradiation is formed. Further, in the region where the crystal 12-1A and the crystal 11-1A formed by the first irradiation intersect, the acicular crystal 1AA is stretched to X-, and the square seed crystal 2AA is formed. Here, the seed crystal 2AA is a crystal surrounded by a substantially closed-loop crystal grain boundary (ridge), and does not include a crystal grain boundary therein. The seed crystal is stretched by subsequent laser light irradiation (third irradiation to eighth irradiation).

  FIG. 38 is a top view of the workpiece 20 when crystallization is performed by third irradiation using the slit 13-1a and the slit 14-1a of the seed crystal stretching mask element 13-1. FIG. 39 is a top view of the workpiece 20 when crystallization is performed by the fourth irradiation using the slit 13-2a and the slit 14-2a of the seed crystal stretching mask element 13-2. . FIG. 40 is a top view of the workpiece 20 when crystallization is performed by fifth irradiation using the slit 13-3a and the slit 14-3a of the seed crystal stretching mask element 13-3. .

  As a result of the third irradiation, crystals 13-1A and crystals 14-1A are formed in the corresponding region as shown in FIG. Further, by this third irradiation, as shown in the figure, the seed crystal 2AA is expanded to Y + and Y−, and as a result, the crystal 3AA is formed. Further, by the fourth irradiation, as shown in FIG. 39, crystals 13-2A and crystals 14-2A are formed in the corresponding region. Further, by this fourth irradiation, as shown in the figure, the crystal 3AA is expanded to Y + and Y−, and as a result, the crystal 4AA is formed. Thereafter, as shown in FIG. 40, crystals 13-3A and crystals 14-3A are formed in the corresponding region by the fifth irradiation. Further, by this fifth irradiation, as shown in the figure, the crystal 4AA is expanded to Y + and Y−, and as a result, the crystal 5AA is formed.

  FIG. 41 is a top view of the workpiece 20 when crystallization is performed by sixth irradiation using the slit 15-1a and the slit 16-1a of the seed crystal stretching mask element 15-1. FIG. 42 is a top view of the workpiece 20 when crystallization is performed by the seventh irradiation using the slit 15-2a and the slit 16-2a of the mask element 15-2 for extending the seed crystal. . FIG. 43 is a top view of the workpiece 20 when crystallization is performed by the eighth irradiation using the slit 15-3a and the slit 16-3a of the seed crystal stretching mask element 15-3. .

  As a result of the sixth irradiation, crystals 15-1A and 16-1A are formed in the corresponding region as shown in FIG. In addition, by the sixth irradiation, the crystal 5AA is expanded to X + and X− as shown in the figure, and as a result, the crystal 6AA is formed. Furthermore, the seventh irradiation forms crystals 15-2A and crystals 16-2A in the corresponding region as shown in FIG. In addition, by the seventh irradiation, as shown in the figure, the crystal 6AA is expanded to X + and X−, and as a result, the crystal 7AA is formed. Thereafter, by the eighth irradiation, crystals 15-3A and crystals 16-3A are formed in the corresponding region. In addition, by the eighth irradiation, as shown in the figure, the crystal 7AA is expanded to X + and X−, and as a result, the crystal 8AA is formed.

Thus, crystallization is completed.
By using such a mask 15b shown in FIG. 35, it is possible to reduce the number of times of irradiation when obtaining a square crystal of the same size as compared with the case of using the mask 15a shown in FIG. Thereby, the crystal production time can be shortened.

  Moreover, since the frequency | count of irradiation can be reduced, the heat storage which generate | occur | produces in the to-be-processed object 20 with the irradiation of a laser beam can be suppressed. Thereby, there exists an effect which reduces the damage of the to-be-processed object 20. FIG.

<Mask configuration change example-3>
By the way, in FIG.3 and FIG.20, the structure of the mask in which one slit was provided in each mask element was shown. FIG. 35 shows a mask configuration in which two slits are provided in various crystal stretching mask elements. However, when the masks shown in FIGS. 3, 20, and 35 are used, only one seed crystal is formed in the one corresponding region.

  Therefore, hereinafter, a configuration in which two seed crystals are formed in the corresponding region by the seed crystal forming mask element will be described with reference to FIGS. More specifically, when the extension to Y +, the extension to Y−, the extension to X +, and the extension to X− are completed in this order, and two square crystals adjacent in the Y-axis direction are formed. Will be described.

FIG. 44 is a diagram showing the configuration of a mask for forming a square crystal.
In the mask 15c shown in the figure, the mask element 21-1 and the mask element 22-1 serve as seed crystal formation mask elements. The other eleven mask elements (23-1, 23-2, 24-1 to 24-3, 25-1 to 25-3, 26-1 to 26-3) are mask elements for seed crystal extension. It becomes.

  Here, as shown in the figure, a seed crystal formation mask element 21-1, a seed crystal extension mask element 23-1, a seed crystal extension mask element 23-2, and a seed crystal extension mask element 24- 1, the seed crystal extension mask element 24-2 and the seed crystal extension mask element 24-3 each have two slits.

  Specifically, the seed crystal forming mask element 21-1 includes a slit 21-1a and a slit 21-b, and the seed crystal forming mask element 22-1 includes a slit 22-1a. The seed crystal stretching mask 23-1 includes slits 23-1a and 23-1b, and the seed crystal stretching mask 23-2 includes slits 23-2a and 23-2b. The seed crystal stretching mask 24-1 includes a slit 24-1a and a slit 24-1b, and the seed crystal stretching mask 24-2 includes a slit 24-2a and a slit 24-2b. -3 includes a slit 24-3a and a slit 24-3b.

  The seed crystal stretching mask 25-1 includes a slit 25-1a, the seed crystal stretching mask 25-2 includes a slit 25-2a, and the seed crystal stretching mask 25-3 includes a slit 25-3a. Yes. The seed crystal extension mask 65-1 includes a slit 26-1a, the seed crystal extension mask 26-2 includes a slit 26-2a, and the seed crystal extension mask 26-3 includes a slit 26-3a. Yes.

  Incidentally, as shown in FIG. 44, the position of each slit in each mask element has the following relationship with the mask of FIG.

  First, the slit 21-1a is provided at the same position as the slit 1-1a, and the slit 22-1a is provided at the same position as the slit 2-1a. Further, the slit 23-1a is provided at the same position as the slit 3-1a, the slit 23-2a is provided at the same position as the slit 3-2a, and the slit 24-3b is provided at the same position as the slit 3-3a. Further, the slit 24-1a is provided at the same position as the slit 4-1a, the slit 24-2a is provided at the same position as the slit 4-2a, and the slit 24-3a is provided at the same position as the slit 4-3a.

  Here, when the distance between the slit 24-3a and the slit 24-3b in the seed crystal extension mask element 24-3 is referred to as an inter-slit distance, the slit 21-1b, the slit 23-1b, the slit 23-2b, and the slit 24 are referred to. -1b and slit 24-2b are the same as the slit 21-1a, slit 23-1a, slit 23-2a, slit 24-1a, and slit 24-2a in the same mask element by the distance between the slits. It is in a position translated in the positive axial direction.

  The slit 25-1a is provided at the same position as the slit 5-1a, the slit 25-2a is provided at the same position as the slit 5-2a, and the slit 25-3a is provided at the same position as the slit 5-3a. Further, the slit 26-1a is provided at the same position as the slit 6-1a, the slit 26-2a is provided at the same position as the slit 6-2a, and the slit 26-3a is provided at the same position as the slit 6-3a.

  As described above, the mask 15c includes the seed crystal forming mask element 21-1 having the slits 21-1a and 21-1b extending in the X-axis direction and the slit 22-1a extending in the Y-axis direction. A seed crystal forming mask element group having a seed crystal forming mask element 22-1 is provided. Further, the mask 15c is arranged following the seed crystal formation mask element 21-1 and the seed crystal formation mask element 22-1, and is arranged along the direction of movement of the mask 23-1a and slit 23-. Seed crystal stretching mask element 23-1 having 1b, seed crystal stretching mask element 24-1 having slit 24-1a and slit 24-1b, and seed crystal stretching mask element 25- having slit 25-1a. 1 and a seed crystal stretching mask element group including a seed crystal stretching mask element 26-1 having a slit 26-1a.

  Here, the center line in the X-axis direction of the slit 21-1a is the first A center line, the center line in the X-axis direction of the slit 21-1b is the first B center line, and the center line in the Y-axis direction of the slit 22-1a. Is defined as the second centerline.

  When each center line is defined in this way, the mask 15c has a portion of the slit 23-1a overlapping the slit 21-1a on one side in the Y-axis direction, and a portion of the slit 23-1b is It is the structure which overlaps with the slit 21-1b in the said one direction side of an axial direction. In the mask 15c, a part of the slit 24-1a overlaps the first A center line on the other direction side in the Y-axis direction, and a part of the slit 24-1b extends in the other direction in the Y-axis direction. It is the structure which overlaps with the said 1B centerline on the side. Further, in the mask 15c, a part of the slit 25-1a overlaps with the slit 22-1a on one side in the X axis direction, and a part of the slit 26-1a is on the other side in the X axis direction. The configuration overlaps the second center line.

  Hereinafter, a process of forming a seed crystal and a process of extending the formed seed crystal using the mask 15c shown in FIG. 44 will be described with reference to FIGS. 45 to 57, the region surrounded by the thin line indicates the region that is crystallized by each irradiation, and the region surrounded by the dotted line is crystallized by the irradiation one time before each irradiation. A region surrounded by a thick line indicates a crystal that is crystallized by the irradiation, and a hatched region indicates a crystal formed by irradiation one time before each irradiation.

  FIG. 45 is a top view of the workpiece 20 when crystallization is performed by the first irradiation using the slit 21-1a and the slit 21-1-b of the seed crystal formation mask element 21-1. .

  In the corresponding region, as shown in FIG. 45, the crystal 21-1A is formed by the slit 21-1a of the seed crystal forming mask element 21-1, and the crystal 21-1B is formed by the slit 21-1b. The Here, the crystal 1AA in FIG. 45 is a part of the crystal 21-1A formed by the first irradiation, and the crystal 1AB is a part of the crystal 21-1B formed by the first irradiation. Further, both the crystal 1AA and the crystal 1AB are elongated needle-like crystals.

  FIG. 46 is a top view of the workpiece 20 when crystallization is performed by the second irradiation using the slit 22-1a of the seed crystal formation mask element 22-1.

  By this second irradiation, as shown in FIG. 46, a crystal 22-1A is formed in the corresponding region. At this time, a needle-like crystal formed by the first irradiation is formed. Further, in the region where the crystal 22-1A and the crystal 21-1A formed by the first irradiation intersect, the acicular crystal 1AA is stretched to X-, and the square seed crystal 2AA is formed. Further, in the region where the crystal 22-1A and the crystal 21-1B formed by the first irradiation intersect, the acicular crystal 1AB is stretched to X-, and the square seed crystal 2AB is formed.

  Here, the seed crystal 2AA and the seed crystal 2AB are crystals surrounded by a substantially closed-loop crystal grain boundary (ridge), and the crystal does not include a crystal grain boundary therein. The seed crystal is stretched by subsequent laser light irradiation (third irradiation to thirteenth irradiation).

  FIG. 47 is a top view of the workpiece 20 when crystallization is performed by third irradiation using the slits 23-1a and 23-1b of the seed crystal stretching mask element 23-1. FIG. 48 is a top view of the workpiece 20 when crystallization is performed by the fourth irradiation using the slit 23-2a and the slit 23-2b of the seed crystal stretching mask element 23-2. .

  As a result of the third irradiation, as shown in FIG. 47, crystals 23-1A and crystals 23-1B are formed in the corresponding region. In addition, by this third irradiation, as shown in the figure, the seed crystal 2AA is expanded to Y +, and as a result, a crystal 3AA is formed. Further, the crystal 2AB is expanded to Y +, and as a result, the crystal 3AB is formed. Thereafter, the fourth irradiation forms crystals 23-2A and crystals 23-2B in the corresponding region as shown in FIG. Further, by this fourth irradiation, as shown in the figure, the crystal 3AA is expanded to Y +, and as a result, the crystal 4AA is formed. Further, the crystal 3AB is expanded to Y +, and as a result, the crystal 4AB is formed.

  FIG. 49 is a top view of the workpiece 20 when crystallization is performed by the fifth irradiation using the slit 24-1a and the slit 24-1b of the seed crystal stretching mask element 24-1. FIG. 50 is a top view of the workpiece 20 when crystallization is performed by sixth irradiation using the slit 24-2a and the slit 24-2b of the seed crystal stretching mask element 24-2. . FIG. 51 is a top view of the workpiece 20 when crystallization is performed by seventh irradiation using the slit 24-3a and the slit 24-3b of the seed crystal stretching mask element 24-3. .

  As a result of the fifth irradiation, crystals 24-1A and 24-1B are formed in the corresponding region as shown in FIG. Further, by the fifth irradiation, as shown in the figure, the crystal 4AA is expanded to Y-, and as a result, the crystal 5AA is formed. Further, the crystal 4AB is expanded to Y-, and as a result, the crystal 5AB is formed. Thereafter, the sixth irradiation forms crystals 24-2A and crystals 24-2B in the corresponding region, as shown in FIG. Further, by this sixth irradiation, the crystal 5AA is stretched to Y- as shown in the figure, and as a result, the crystal 6AA is formed. Further, the crystal 5AB is stretched to Y-, and as a result, the crystal 6AB is formed.

  Thereafter, the seventh irradiation forms crystals 24-3A and crystals 24-3B in the corresponding region as shown in FIG. In addition, by the seventh irradiation, as shown in the figure, the crystal 6AA is expanded to Y− and Y +, and as a result, the crystal 7AA is formed. Also, the crystal 6AB is stretched to Y-, and as a result, the crystal 7AB is formed. That is, as shown in the figure, in the final extension in the adjacent direction (Y-axis direction) of the adjacent seed crystals (2AA, 2AB), the crystals 6AA and 6AB are in opposite directions toward the boundary between the adjacent seed crystals. And the growing crystals collide simultaneously at the boundary.

  From this point, in the mask 15c shown in FIG. 44, in the final extension in the Y-axis direction, the slit used for extending 6AA to Y + is used as the slit used for extending 6AB to Y− (in FIG. It can be said that the slit is arranged so that 24-3b) is also used.

  FIG. 52 is a top view of the workpiece 20 when crystallization is performed by the eighth irradiation using the slit 25-1a of the seed crystal stretching mask element 25-1. FIG. 53 is a top view of the workpiece 20 when crystallization is performed by the ninth irradiation using the slit 25-2a of the seed crystal stretching mask element 25-2. FIG. 54 is a top view of the workpiece 20 when crystallization is performed by the tenth irradiation using the slit 25-3a of the mask element 25-3 for seed crystal extension.

  As a result of the eighth irradiation, a crystal 25-1A is formed in the corresponding region as shown in FIG. In addition, by the eighth irradiation, as shown in the figure, the crystal 7AA is expanded to X +, and as a result, the crystal 8AA is formed. Further, the crystal 7AB is expanded to X +, and as a result, the crystal 8AB is formed. Thereafter, by the ninth irradiation, a crystal 25-2A is formed in the corresponding region as shown in FIG. In addition, by the ninth irradiation, as shown in the figure, the crystal 8AA is expanded to X +, and as a result, the crystal 9AA is formed. Further, the crystal 8AB is expanded to X +, and as a result, the crystal 9AB is formed. Further, by the tenth irradiation, crystals 25-3A are formed in the corresponding region as shown in FIG. In addition, by the tenth irradiation, the crystal 9AA is expanded to X + as shown in the figure, and as a result, the crystal 10AA is formed. Further, the crystal 9AB is expanded to X +, and as a result, the crystal 10AB is formed.

  FIG. 55 is a top view of the workpiece 20 when crystallization is performed by the eleventh irradiation using the slit 26-1a of the seed crystal stretching mask element 26-1. FIG. 56 is a top view of the workpiece 20 when crystallization is performed by the twelfth irradiation using the slit 26-2a of the seed crystal stretching mask element 26-2. FIG. 57 is a top view of the workpiece 20 when crystallization is performed by thirteenth irradiation using the slit 26-3a of the seed crystal stretching mask element 26-3.

  As a result of the eleventh irradiation, a crystal 26-1A is formed in the corresponding region as shown in FIG. Further, as a result of this eleventh irradiation, the crystal 10AA is expanded to X- as shown in the figure, and as a result, the crystal 11AA is formed. Further, the crystal 10AB is expanded to X-, and as a result, the crystal 11AB is formed. Thereafter, the twelfth irradiation forms crystals 26-2A in the corresponding region as shown in FIG. In addition, as a result of the twelfth irradiation, the crystal 11AA is expanded to X− as shown in the figure, and as a result, the crystal 12AA is formed. Further, the crystal 11AB is expanded to X-, and as a result, the crystal 12AB is formed. Thereafter, as a result of the thirteenth irradiation, crystals 26-3A are formed in the corresponding region as shown in FIG. In addition, as a result of the thirteenth irradiation, the crystal 12AA is expanded to X− as shown in the figure, and as a result, the crystal 13AA is formed. Further, the crystal 12AB is expanded to X-, and as a result, the crystal 13AB is formed.

Thus, crystallization is completed.
As described above, in the mask 15c shown in FIG. 44, in the final extension of the adjacent seed crystal in the adjacent direction, it grows in the opposite direction toward the boundary between the adjacent seed crystals, and the grown crystal collides simultaneously with the boundary. It can be said that a slit pattern having such an arrangement and shape is formed.

  That is, the mask 15c shown in FIG. 44 is used for final extension to Y + when the seed crystal 2AA is extended to form the square crystal 13AA, and the seed crystal 2AB is extended to form the square crystal 13AB. It can be said that the slit is arranged so that the slit is also used for the final extension to Y−.

  The mask 15c shown in FIG. 44 does not include a mask element corresponding to the seed crystal stretching mask element 3-3 shown in the mask 15 shown in FIG. By using such a mask 15c shown in FIG. 44, it is possible to form a plurality of adjacent square crystals without a gap as shown in FIG.

  In the above description, the configuration in which the square crystals are adjacent to each other in the Y-axis direction has been described as an example. However, the present invention is not limited to this. For example, the slits of the seed crystal forming mask element 21-1 are arranged along the Y-axis direction, and the slits of the seed crystal forming mask element 22-1 are arranged along the X-axis direction. In the structure, the square crystals can be adjacent to each other.

<Moving the stage in the Y-axis direction>
In the above description, it has been described that the square crystal is formed by moving the mask in the relative movement direction of the mask (negative direction in the X-axis direction). In the following, after the square crystal is formed by such movement and the stage is returned to the default position, the workpiece 20 is moved in the Y-axis direction by a predetermined distance by moving the stage in the Y-axis direction by a predetermined distance. A configuration in which the square crystal is formed again in a region different from the region where the square crystal is formed in the object to be processed 20 by moving the distance (hereinafter referred to as a line feed amount) will be described.

  A process of forming a plurality of square crystals by repeating such formation of the square crystals and movement of a predetermined distance in the Y-axis direction (hereinafter referred to as a line feed amount) will be described below with reference to FIG. Description will be made with reference to FIG. Hereinafter, a region where a square crystal is formed is referred to as a crystal region.

  Here, a mask obtained by removing the seed crystal stretching mask element 3-3 from the mask 15 shown in FIG. 3 is used. That is, a mask having a configuration in which the seed crystal stretching mask element 4-1 is adjacent to the seed crystal stretching mask element 3-2 is used. Further, in the final extension in the adjacent direction (Y-axis direction) for the crystallization regions adjacent to each other, the crystal grows in the opposite direction toward the boundary between the adjacent crystallization regions, and the crystal grown at the boundary The above line feed amount is set so as to collide simultaneously.

  In FIGS. 58 to 70, a region surrounded by a thin line indicates a region that is crystallized by each irradiation, a region surrounded by a thick line indicates a crystal that is crystallized by the irradiation, and hatched lines are applied. The region shown is a crystal formed by irradiation one time before each irradiation.

  FIG. 58 shows a seed crystal formation mask element with respect to the second crystallization region after the workpiece 20 is moved by the line feed amount after a square crystal is formed partway in the first crystallization region. It is a top view of the to-be-processed object 20 at the time of crystallizing by 1st irradiation using the slit 1-1a of 1-1.

  In the corresponding region, as shown in FIG. 58, the crystal 1-1A is formed by the slit 1-1a of the seed crystal forming mask element 1-1. Here, the crystal 1AB in FIG. 58 is a part of the crystal 1-1A formed by the first irradiation, and is an elongated needle-like crystal.

  FIG. 59 is a top view of the workpiece 20 when crystallization is performed by the second irradiation using the slit 2-1a of the seed crystal formation mask element 2-1.

  By this second irradiation, as shown in FIG. 59, a crystal 2-1A is formed in the corresponding region. At this time, a needle-like crystal formed by the first irradiation is formed. Further, in the region where the crystal 2-1A and the crystal 1-1A formed by the first irradiation intersect, the acicular crystal 1AB is stretched to X-, and the square seed crystal 2AB is formed. Here, the seed crystal 2AB is a crystal surrounded by a substantially closed-loop crystal grain boundary (ridge), and does not include a crystal grain boundary therein. The seed crystal is stretched by subsequent laser light irradiation (third irradiation to thirteenth irradiation). As shown in the figure, the centroid of the crystal 2AB is the origin of the XY coordinate system.

  FIG. 60 is a top view of the workpiece 20 when crystallization is performed by the third irradiation using the slit 3-1a of the seed crystal stretching mask element 3-1. FIG. 61 is a top view of the workpiece 20 when crystallization is performed by the fourth irradiation using the slit 3-2a of the mask element 3-2 for extending the seed crystal.

  By the third irradiation, as shown in FIG. 60, a crystal 3-1A is formed in the corresponding region (second crystallization region). In addition, by this third irradiation, the seed crystal 2AB is expanded to Y + as shown in the figure, and as a result, the crystal 3AB is formed. Thereafter, as shown in FIG. 61, crystal 3-2A is formed in the corresponding region by the fourth irradiation. Further, by this fourth irradiation, as shown in the figure, the crystal 3AB is expanded to Y +, and as a result, the crystal 4AB is formed.

  FIG. 62 is a top view of the workpiece 20 when crystallization is performed by the fifth irradiation using the slit 4-1a of the seed crystal stretching mask element 4-1. FIG. 63 is a top view of the workpiece 20 when crystallization is performed by sixth irradiation using the slit 4-2a of the seed crystal stretching mask element 4-2. FIG. 64 is a top view of the workpiece 20 when crystallization is performed by the seventh irradiation using the slit 4-3a of the seed crystal stretching mask element 4-3.

  As a result of the fifth irradiation, a crystal 4-1A is formed in the corresponding region as shown in FIG. Further, by this fifth irradiation, as shown in the figure, the crystal 4AB is expanded to Y-, and as a result, the crystal 5AB is formed. Thereafter, the sixth irradiation forms crystals 4-2A in the corresponding region as shown in FIG. In addition, by the sixth irradiation, as shown in the figure, the crystal 5AB is expanded to Y-, and as a result, the crystal 6AB is formed. Thereafter, as a result of the seventh irradiation, crystals 4-3A are formed in the corresponding region as shown in FIG. In addition, by the seventh irradiation, as shown in the figure, the crystal 6AB is expanded to Y-, and as a result, the crystal 7AB is formed. Furthermore, as shown in the figure, the crystal 6AA is expanded to Y +, and as a result, the crystal 7AA is formed.

  That is, as shown in the figure, in the final extension in the adjacent direction (Y-axis direction) of the adjacent seed crystal (the seed crystal 2AA (not shown) formed in the first crystallization region, the seed crystal 2AB), Crystals 6AA and 6AB grow in opposite directions toward the boundary between the seed crystals, and the grown crystals collide simultaneously at the boundary.

  FIG. 65 is a top view of the workpiece 20 when crystallization is performed by the eighth irradiation using the slit 5-1a of the seed crystal stretching mask element 5-1. FIG. 66 is a top view of the workpiece 20 when crystallization is performed by the ninth irradiation using the slit 5-2a of the seed crystal stretching mask element 5-2. FIG. 67 is a top view of the workpiece 20 when crystallization is performed by the tenth irradiation using the slit 5-3a of the seed crystal stretching mask element 5-3.

  As a result of the eighth irradiation, a crystal 5-1A is formed in the corresponding region as shown in FIG. In addition, by the eighth irradiation, as shown in the figure, the seed crystal 7AB is expanded to X +, and as a result, the crystal 8AB is formed. Thereafter, by the ninth irradiation, as shown in FIG. 66, a crystal 5-2A is formed in the corresponding region. In addition, by the ninth irradiation, as shown in the figure, the crystal 8AB is expanded to X +, and as a result, the crystal 9AB is formed. Thereafter, as a result of the tenth irradiation, crystals 5-3A are formed in the corresponding region as shown in FIG. In addition, by the tenth irradiation, the crystal 9AB is expanded to X + as shown in the figure, and as a result, the crystal 10AB is formed.

  FIG. 68 is a top view of the workpiece 20 when crystallization is performed by eleventh irradiation using the slit 6-1a of the seed crystal stretching mask element 6-1. FIG. 69 is a top view of the workpiece 20 when crystallization is performed by the twelfth irradiation using the slit 6-2a of the seed crystal stretching mask element 6-2. FIG. 70 is a top view of the workpiece 20 when crystallization is performed by the thirteenth irradiation using the slit 6-3a of the seed crystal stretching mask element 6-3.

  As a result of the eleventh irradiation, a crystal 6-1A is formed in the corresponding region as shown in FIG. In addition, as a result of the eleventh irradiation, the seed crystal 10AB is expanded to X- as shown in the figure, and as a result, the crystal 11AB is formed. Thereafter, as a result of the twelfth irradiation, a crystal 6-2A is formed in the corresponding region as shown in FIG. In addition, as a result of the twelfth irradiation, the crystal 11AB is expanded to X- as shown in the figure, and as a result, the crystal 12AB is formed. Thereafter, the 13th irradiation forms crystals 6-3A in the corresponding region as shown in FIG. In addition, as a result of the thirteenth irradiation, the crystal 12AB is expanded to X- as shown in the figure, and as a result, the crystal 13AB is formed.

Thus, crystallization is completed.
The laser crystallization apparatus 1 that performs such crystallization extends the seed crystal 2AA in the first crystallization region to form the square crystal 13AA, and extends the seed crystal 2AB in the second crystallization region to When forming the mold crystal 13AB, the slit arrangement and the amount of line breaks are such that the slit used for the final extension of the square crystal 13AA to Y + is also used as the slit used for the final extension of the square crystal 13AB to Y-. It can be said that the configuration is set.

  Further, by performing crystallization using the apparatus having such a configuration, adjacent crystallization regions can be formed without gaps as shown in FIG. In the above description, the configuration in which movement (line feed) is performed in the positive direction (Y +) in the Y-axis direction has been described as an example. .

  By the way, generally, when the channel size of the TFT is larger than that of the square crystal, the region other than the square crystal in the channel is composed of a non-crystallized film (amorphous semiconductor film). . Since such a TFT includes a film that is not crystallized, the characteristics are lower than those of a TFT that does not include such a film.

  On the other hand, in order to obtain a high-performance TFT when the channel size is large, it is necessary to fill the channel with square crystals. As this means, a square crystal larger than the channel size is formed, and a channel is arranged in the square crystal, and a square crystal in which a plurality of square crystals as shown in FIG. There is a method of forming a group and arranging a channel in the square crystal group.

  As described above, in the configuration in which the amount of line feed is moved to form a square crystal, as shown in FIG. 70, a plurality of square shapes are formed by forming adjacent square crystals (adjacent crystallization regions). A square crystal group in which a plurality of crystals are arranged with a ridge therebetween can be obtained. Therefore, by using the square crystal group, a high-performance TFT can be manufactured even when the channel size is large.

<Other examples of mask configuration changes>
By the way, in the above, the example which is a pattern which the arrangement pattern of the some slit in the mask element group for seed crystal formation cross | intersects was demonstrated. However, the present invention is not limited to this, and may be a pattern that intersects needle crystals (for example, the needle crystals shown in FIG. 98B) that are stretched while overlapping a part of the irradiation regions.

  In this case, the crystal width of the acicular crystal can be made uniform by stretching the crystal while overlapping a part of the irradiation regions. For this reason, the rectangular seed crystal that is formed when laser light is irradiated using slits having patterns that intersect each other later has a more uniform crystallinity than a configuration in which some irradiation regions are not overlapped. become.

  In the mask 15 shown in FIG. 3 and the mask 15a shown in FIG. 20, the example of j = k = l = m = 3 is shown. However, the present invention is not limited to this, and j, k, Larger square crystals can be obtained as l and m increase.

  Further, in the present embodiment, an example in which the width of the slit of the mask element for seed crystal formation and the width of the slit of the mask element for seed crystal extension are the same width has been described. However, the present invention is not limited to this, and the width of the slit of the seed crystal forming mask element in the seed crystal forming mask group is the same as the width of the slit of the seed crystal extending mask element in the seed crystal extending mask group. It suffices to be smaller than the slit width of the mask element for extending the seed crystal. This is because a narrower rectangular seed crystal can be obtained as the slit width of the seed crystal forming mask element in the seed crystal forming mask group is narrower.

  By the way, in the above example, the seed crystal is extended in the positive direction in the X-axis direction, the negative direction in the X-axis direction, the positive direction in the Y-axis direction, and the negative direction in the Y-axis direction. Although described above, the present invention is not limited to this.

  The seed crystal is extended in at least three directions among a positive direction in the X-axis direction, a negative direction in the X-axis direction, a positive direction in the Y-axis direction, and a negative direction in the Y-axis direction. I just need it. Even with such a configuration, for example, a large square crystal can be obtained as compared with the conventional configuration in which the seed crystal is expanded only in the positive and negative directions in the X-axis direction and in the positive direction in the Y-axis direction.

  Such a mask configuration is obtained by, for example, removing the seed crystal stretching mask element used for stretching in the negative direction in the Y-axis direction, for example, from the mask 15 shown in FIG. What is necessary is just to make it the structure which makes it adjoin. In this case, the seed crystal extends in a positive direction in the X-axis direction, a negative direction in the X-axis direction, and a positive direction in the Y-axis direction.

  That is, a mask element for extending in a positive direction in the X axis direction, a mask element for extending in a negative direction in the X axis direction, a mask element for extending in a positive direction in the Y axis direction, By adopting a configuration in which any of the mask elements for extending in the negative direction of the Y-axis direction is not provided, the seed crystal can be extended only in three of these four directions. it can.

[Embodiment 2]
A laser crystallization apparatus according to another embodiment of the present invention will be described below with reference to FIGS. Note that members shown in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The laser crystallization apparatus according to the present embodiment is the same as the laser crystallization apparatus 1 of the first embodiment except that the mask configuration is different from the mask configuration shown in the first embodiment. is there.

  In the first embodiment, a laser crystallization method that extends in the X-axis direction after the extension in the Y-axis direction is completed, or a laser that extends in the Y-axis direction after the extension in the X-axis direction is completed. The crystallization method has been described. On the other hand, the present embodiment is different from the laser crystallization method of the first embodiment, and the crystal is stretched while alternately repeating stretching in the X-axis direction and stretching in the Y-axis direction.

Hereinafter, a process of forming a square crystal will be described with a specific mask configuration.
FIG. 71 is a diagram showing a configuration of a mask for forming a square crystal used in the present embodiment.

  The mask 150 shown in the figure is different from the seed crystal extension mask elements in the mask 15 shown in FIG. 3 in the arrangement of the seed crystal extension mask elements. Otherwise, the mask 150 shown in FIG. 71 and the mask 15 shown in FIG. 3 are the same.

  Hereinafter, a process of forming a seed crystal and a process of extending the formed seed crystal using the mask 150 shown in FIG. 71 will be described with reference to FIGS. 72 to 85, the region surrounded by a thin line indicates a region that is crystallized by each irradiation, and the region surrounded by a dotted line is crystallized by irradiation one time before each irradiation. A region surrounded by a thick line indicates a crystal that is crystallized by the irradiation, and a hatched region indicates a crystal formed by irradiation one time before each irradiation.

  FIG. 72 is a top view of the workpiece 20 when crystallization is performed by the first irradiation using the slit 1-1a of the seed crystal forming mask element 1-1.

  In the corresponding region, as shown in FIG. 72, a crystal 1-1A is formed by the slit 1-1a of the seed crystal forming mask element 1-1. Here, the crystal 1AA in FIG. 72 is a part of the crystal 1-1A formed by the first irradiation, and is an elongated needle-like crystal.

  FIG. 73 is a top view of the workpiece 20 when crystallization is performed by the second irradiation using the slit 2-1a of the seed crystal formation mask element 2-1.

  By this second irradiation, as shown in FIG. 73, a crystal 2-1A is formed in the corresponding region. At this time, a needle-like crystal formed by the first irradiation is formed. Further, in a region where the crystal 2-1A and the crystal 1-1A formed by the first irradiation intersect, the acicular crystal 1AA is stretched to X-, and a square seed crystal 2AA is formed. Here, the seed crystal 2AA is a crystal surrounded by a substantially closed-loop crystal grain boundary (ridge), and does not include a crystal grain boundary therein. The seed crystal is stretched by subsequent laser light irradiation (third irradiation to fourteenth irradiation).

  FIG. 74 is a top view of the workpiece 20 when crystallization is performed by the third irradiation using the slit 3-1a of the seed crystal stretching mask element 3-1. FIG. 75 is a top view of the workpiece 20 when crystallization is performed by the fourth irradiation using the slit 4-1a of the seed crystal stretching mask element 4-1.

  As a result of the third irradiation, a crystal 3-1A is formed in the corresponding region as shown in FIG. In addition, by this third irradiation, as shown in the figure, the seed crystal 2AA is expanded to Y +, and as a result, a crystal 3AA is formed. Thereafter, the fourth irradiation forms crystals 4-1A in the corresponding region, as shown in FIG. In addition, the fourth irradiation causes the crystal 3AA to expand to Y- as shown in the figure, and as a result, the crystal 4AA is formed.

  FIG. 76 is a top view of the workpiece 20 when crystallization is performed by the fifth irradiation using the slit 5-1a of the seed crystal stretching mask element 5-1. FIG. 77 is a top view of the workpiece 20 when crystallization is performed by sixth irradiation using the slit 6-1a of the mask element 6-1 for extending the seed crystal.

  As a result of the fifth irradiation, a crystal 5-1A is formed in the corresponding region as shown in FIG. In addition, by the fifth irradiation, as shown in the figure, the crystal 4AA is expanded to X +, and as a result, the crystal 5AA is formed. Thereafter, the sixth irradiation forms crystals 6-1A in the corresponding region, as shown in FIG. In addition, by the sixth irradiation, the crystal 5AA is expanded to X− as shown in the figure, and as a result, the crystal 6AA is formed.

  FIG. 78 is a top view of the workpiece 20 when crystallization is performed by seventh irradiation using the slit 3-2a of the mask element 3-2 for seed crystal extension. FIG. 79 is a top view of the workpiece 20 when crystallization is performed by the eighth irradiation using the slit 4-2a of the seed crystal stretching mask element 4-2.

  As a result of the seventh irradiation, a crystal 3-2A is formed in the corresponding region as shown in FIG. In addition, by the seventh irradiation, as shown in the figure, the crystal 6AA is expanded to Y +, and as a result, the crystal 7AA is formed. Thereafter, as shown in FIG. 79, the crystal 4-2A is formed in the corresponding region by the eighth irradiation. Further, by the eighth irradiation, as shown in the figure, the crystal 7AA is expanded to Y-, and as a result, the crystal 8AA is formed.

  FIG. 80 is a top view of the workpiece 20 when crystallization is performed by the ninth irradiation using the slit 5-2a of the seed crystal stretching mask element 5-2. FIG. 81 is a top view of the workpiece 20 when crystallization is performed by the tenth irradiation using the slit 6-2a of the seed crystal stretching mask element 6-2.

  As a result of the ninth irradiation, a crystal 5-2A is formed in the corresponding region as shown in FIG. In addition, by the ninth irradiation, the seed crystal 8AA is expanded to X + as shown in the figure, and as a result, the crystal 9AA is formed. Thereafter, the tenth irradiation forms crystals 6-2A in the corresponding region, as shown in FIG. Further, by the tenth irradiation, the crystal 9AA is expanded to X− as shown in the figure, and as a result, the crystal 10AA is formed.

  FIG. 82 is a top view of the workpiece 20 when crystallization is performed by the eleventh irradiation using the slit 3-3a of the seed crystal stretching mask element 3-3. FIG. 83 is a top view of the workpiece 20 when crystallization is performed by the twelfth irradiation using the slit 4-3a of the mask element 4-3 for seed crystal extension.

  As a result of the eleventh irradiation, a crystal 3-3A is formed in the corresponding region as shown in FIG. In addition, by the eleventh irradiation, as shown in the figure, the crystal 10AA is expanded to Y +, and as a result, the crystal 11AA is formed. Thereafter, by the twelfth irradiation, a crystal 4-3A is formed in the corresponding region as shown in FIG. Further, by this twelfth irradiation, as shown in the figure, the seed crystal 11AA is expanded to Y-, and as a result, the crystal 12AA is formed.

  FIG. 84 is a top view of the workpiece 20 when crystallization is performed by thirteenth irradiation using the slit 5-3a of the seed crystal stretching mask element 5-3. FIG. 85 is a top view of the workpiece 20 when crystallization is performed by the fourteenth irradiation using the slit 6-3a of the mask element 6-3 for extending the seed crystal.

  As a result of the thirteenth irradiation, a crystal 5-3A is formed in the corresponding region as shown in FIG. Further, by this thirteenth irradiation, as shown in the figure, the crystal 12AA is expanded to X +, and as a result, the crystal 13AA is formed. Thereafter, the 14th irradiation forms crystals 6-3A in the corresponding region as shown in FIG. In addition, as a result of the fourteenth irradiation, the crystal 13AA is expanded to X- as shown in the figure, and as a result, the crystal 14AA is formed.

Thus, crystallization is completed.
As a result, by using the mask 150, as shown in FIG. 85, a square crystal having the same size as that of the square crystal obtained when the mask 15 shown in FIG. 3 is used can be obtained.

  As described above, in the present embodiment, the seed crystal can be alternately extended little by little in the X-axis direction and the Y-axis direction by using the mask 150. Therefore, in this embodiment, the crystal grain cracking described in the first embodiment, for example, than the square crystal obtained by stretching the crystal obtained by stretching the seed crystal in the Y-axis direction in the X-axis direction. Can be obtained.

<Mask configuration change example>
Next, the crystal is stretched while alternately repeating the stretching in the X-axis direction and the stretching in the Y-axis direction, the stretching to Y + and the stretching to Y− are simultaneously performed, and the stretching to X + and the X− A configuration for performing the expansion at the same time will be described with reference to FIGS. 86 to 94.

  FIG. 86 is a diagram showing a configuration of a mask for forming a square crystal. The mask 150a shown in the figure has a slit for extending to Y + and a slit for extending to Y− in the same mask element, and the slit for extending to X + and the slit for extending to X− are the same mask. Placed in the element.

  In the mask 150a, the arrangement of the seed crystal stretching mask elements is different from the seed crystal stretching mask elements in the mask 15b shown in the first embodiment (see FIG. 35). Otherwise, the mask 150a shown in FIG. 86 and the mask 15b shown in FIG. 35 are the same. In FIG. 86, the same reference numerals are assigned to the same mask elements as the seed crystal stretching mask elements of the mask 15b shown in FIG.

  Hereinafter, a process of forming a seed crystal and a process of extending the formed seed crystal using the mask 150a shown in FIG. 86 will be described with reference to FIGS. In FIGS. 87 to 94, the region surrounded by the thin line indicates the region that is crystallized by each irradiation, and the region surrounded by the dotted line is crystallized by the irradiation one time before each irradiation. A region surrounded by a thick line indicates a crystal that is crystallized by the irradiation, and a hatched region indicates a crystal formed by irradiation one time before each irradiation.

  FIG. 87 is a top view of the workpiece 20 when crystallization is performed by the first irradiation using the slit 11-1a of the mask element 11-1 for seed crystal formation.

  In the corresponding region, as shown in FIG. 87, the crystal 11-1A is formed by the slit 11-1a of the seed crystal forming mask element 11-1. Here, the crystal 1AA in FIG. 36 is a part of the crystal 11-1A formed by the first irradiation, and is an elongated needle-like crystal.

  FIG. 88 is a top view of the workpiece 20 when crystallization is performed by the second irradiation using the slit 12-1a of the seed crystal forming mask element 12-1.

  By this second irradiation, crystals 12-1A are formed in the corresponding region as shown in FIG. At this time, a needle-like crystal formed by the first irradiation is formed. Further, in the region where the crystal 12-1A and the crystal 11-1A formed by the first irradiation intersect, the acicular crystal 1AA is stretched to X-, and the square seed crystal 2AA is formed. Here, the seed crystal 2AA is a crystal surrounded by a substantially closed-loop crystal grain boundary (ridge), and does not include a crystal grain boundary therein. The seed crystal is stretched by subsequent laser light irradiation (third irradiation to eighth irradiation).

  FIG. 89 is a top view of the workpiece 20 when crystallization is performed by the third irradiation using the slit 13-1a and the slit 14-1a of the seed crystal stretching mask element 13-1. FIG. 90 is a top view of the workpiece 20 when crystallization is performed by the fourth irradiation using the slit 15-1a and the slit 16-1a of the seed crystal stretching mask element 15-1. .

  By the third irradiation, as shown in FIG. 89, crystals 13-1A and crystals 14-1A are formed in the corresponding region. Further, by this third irradiation, as shown in the figure, the seed crystal 2AA is expanded to Y + and Y−, and as a result, the crystal 3AA is formed. Thereafter, the fourth irradiation forms crystals 15-1A and crystals 16-1A in the corresponding region as shown in FIG. In addition, by the fourth irradiation, as shown in the figure, the crystal 3AA is expanded to X + and X−, and as a result, the crystal 4AA is formed.

  FIG. 91 is a top view of the workpiece 20 when crystallization is performed by fifth irradiation using the slit 13-2a and the slit 14-2a of the seed crystal extension mask element 13-2. FIG. 92 is a top view of the workpiece 20 when crystallization is performed by the sixth irradiation using the slit 15-2a and the slit 16-2a of the seed crystal stretching mask element 15-2. .

  With the fifth irradiation, as shown in FIG. 91, crystals 13-2A and crystals 14-2A are formed in the corresponding region. Further, by this fifth irradiation, as shown in the figure, the crystal 4AA is expanded to Y + and Y−, and as a result, the crystal 5AA is formed. Thereafter, by the sixth irradiation, as shown in FIG. 92, crystals 15-2A and crystals 16-2A are formed in the corresponding region. In addition, by the sixth irradiation, the crystal 5AA is expanded to X + and X− as shown in the figure, and as a result, the crystal 6AA is formed.

  FIG. 93 is a top view of the workpiece 20 when crystallization is performed by the seventh irradiation using the slit 13-3a and the slit 14-3a of the seed crystal stretching mask element 13-3. FIG. 94 is a top view of the workpiece 20 when crystallization is performed by the eighth irradiation using the slit 15-3a and the slit 16-3a of the seed crystal stretching mask element 15-3. .

  As a result of the seventh irradiation, crystals 13-3A and crystals 14-3A are formed in the corresponding region as shown in FIG. Further, by this seventh irradiation, as shown in the figure, the crystal 6AA is expanded to Y + and Y−, and as a result, the crystal 7AA is formed. Thereafter, the eighth irradiation forms crystals 15-3A and crystals 16-3A in the corresponding region. In addition, by the eighth irradiation, as shown in the figure, the crystal 7AA is expanded to X + and X−, and as a result, the crystal 8AA is formed.

Thus, crystallization is completed.
Use of such a mask 150a shown in FIG. 86 makes it possible to reduce the number of times of irradiation when obtaining a square crystal of the same size as compared with the case of using mask 150 shown in FIG. Thereby, the crystal production time can be shortened.

  Moreover, since the frequency | count of irradiation can be reduced, the heat storage which generate | occur | produces in the to-be-processed object 20 with the irradiation of a laser beam can be suppressed. Thereby, there exists an effect which reduces the damage of the to-be-processed object 20. FIG.

  Further, also in the present embodiment, as described in the first embodiment, the structure is such that a square crystal is formed by moving by the amount of line feed, and adjacent square crystals (adjacent crystallization regions) are formed. Thus, a square crystal group in which a plurality of square crystals are arranged with a ridge therebetween can be obtained. Therefore, by using the square crystal group, a high-performance TFT can be manufactured even when the channel size is large.

[Embodiment 3]
A laser crystallization apparatus according to another embodiment of the present invention will be described below with reference to FIG. In addition, the same code | symbol is attached | subjected about the member shown in Embodiment 1 and Embodiment 2, and the description is abbreviate | omitted.

FIG. 95 is a diagram showing a schematic configuration of the laser crystallization apparatus 100.
As shown in the figure, the laser crystallization apparatus 100 includes a laser oscillator 10, a variable attenuator 11, a mirror 12, a mirror 13, an illumination optical element 14, a mask 15, an imaging lens 16, and a mirror. 17, a stage 18, a control device 19, a laser light oscillator 30, a variable attenuator 31, and a mirror 32. On the stage 18, a workpiece 20 to be irradiated with laser light is placed.

  That is, the laser crystallization apparatus 100 according to the present embodiment is different from the members included in the laser crystallization apparatus 1 in that it further includes the laser light oscillator 30, the variable attenuator 31, and the mirror 32. This is different from the laser crystallization apparatus 1.

  The laser light oscillator 30 is not particularly limited as long as it can irradiate laser light having a wavelength with a high absorption rate to the amorphous semiconductor thin film 23 in a solid state. For example, a carbon dioxide laser oscillator having a wavelength of 10.6 μm can be used as the laser oscillator 30. Here, the energy amount per irradiation of the laser light emitted from the laser light oscillator 30 is less than the energy amount to be melted in the thickness direction of the amorphous semiconductor thin film 23 in the solid state.

  The variable attenuator 31 attenuates the power of the laser light emitted from the laser light oscillator 30 through absorption and scattering of the laser light. In particular, the variable attenuator 31 can change the amount of attenuation by an external signal or an adjustment knob. The pulse laser beam attenuated by the variable attenuator 31 is emitted toward the mirror 32.

  The mirror 32 reflects the pulse laser beam emitted from the variable attenuator 31 toward the workpiece 20 on the stage 18.

  That is, in the laser crystallization apparatus 100, the laser light emitted from the laser light oscillator 300 passes through the variable attenuator 31 and enters the surface of the workpiece 20 placed on the stage 18.

  In the laser crystallization apparatus 100, a laser beam emitted from the laser beam oscillator 10 (hereinafter referred to as a first laser beam) and a laser beam emitted from the laser beam oscillator 30 (hereinafter referred to as a second laser beam). ) Is irradiated to the workpiece 20 at the same time. In the present embodiment, the control device 19 further controls the timing of laser light emission in the laser light oscillator 30.

  Regarding the incident direction of the laser beam to the workpiece 20, for example, the first laser beam emitted from the laser beam oscillator 10 is incident on the amorphous semiconductor thin film 23 from the vertical direction and emitted from the laser beam oscillator 30. The second laser beam is incident on the amorphous semiconductor thin film 23 from an oblique direction.

  In addition, a laser light irradiation area (hereinafter referred to as a second irradiation area) in the object 20 to be processed by the second laser light is an irradiation area (hereinafter referred to as a first irradiation area) in the object 20 to be processed by the first laser light. The second laser light is adjusted so as to be an area wider than the first irradiation area.

  Further, the control device 19 starts irradiating the workpiece 20 with the first laser beam after starting the irradiation of the workpiece 20 with the second laser beam, and before ending the irradiation with the second laser beam. Then, the irradiation of the first laser beam is terminated.

  In the laser crystallization apparatus 100, the first irradiation region and the second irradiation region are set as described above, and the irradiation timing of the first laser beam and the second laser beam is set as described above, thereby melting the first irradiation region and the second irradiation region as described above. The time until the amorphous semiconductor film 23 in the state is solidified can be extended.

  Therefore, compared to the configuration in which only the first laser beam is irradiated, the laser crystallization apparatus 100 can greatly extend the crystal growth distance. Therefore, the crystal growth can be made longer by one irradiation of the first laser light as compared with the configurations of the first and second embodiments.

  Therefore, the slit width of the slit in the mask 15 can be increased. Therefore, in the present embodiment, a larger square crystal can be formed as compared with the first and second embodiments.

  In the above description, the mask 15 has been described as an example. However, the present invention is not limited to this. The mask 15a, the mask 15b, the mask 15c, the mask 150, or the mask 150a may be used instead of the mask 15. Good.

  Although not shown in FIG. 95, a beam shaping optical system for shaping the laser light emitted from the laser light oscillator 30 to a desired size with respect to the laser crystallization apparatus 100 or a uniform laser light. A beam homogenizing optical system for irradiating with intensity may be introduced as necessary.

  In the above description, the first laser light is incident on the amorphous semiconductor thin film 23 from the vertical direction, and the second laser light is incident on the amorphous semiconductor thin film 23 from an oblique direction. It is not limited to the direction.

  In addition, the configuration in which the second irradiation region includes the first irradiation region has been described as an example. However, even when the second irradiation region does not completely include the first irradiation region, the irradiation regions overlap. If there is a region that is present, the above-described effects can be obtained for the region.

  In addition, although the slit shape of the mask used in each said embodiment was made into the rectangular shape, it is not limited to this. For example, the slit shape may be a circle or an ellipse.

  In the above description, the configuration in which the stage 18 moves is described as an example. However, the present invention is not limited to this, and a configuration in which the mask moves may be used.

  In the above description, the mask is composed of each mask element. That is, the configuration using a single physical mask has been described. However, a configuration in which a plurality of masks are combined to form one mask may be used. In this case, each mask among the plurality of masks corresponds to a mask element.

  Further, in each of the above-described embodiments, the configuration using two intersecting slits has been described as an example of the method for forming a seed crystal. However, the present invention is not limited to this. For example, a needle-like crystal formed by a single slit (for example, slit 1-1a in FIG. 3) may be the above-described seed crystal, and the seed crystal may be stretched by a seed crystal stretching mask element group. Alternatively, a circular crystal formed using a mask having a circular opening (circular slit) may be used as the seed crystal, and the seed crystal may be stretched by the seed crystal stretching mask element group. Further, the seed crystal may be formed using three or more slits such as a first slit, a slit arranged perpendicular to the first slit, and a slit parallel to the first slit.

  In addition, when the seed crystal is extended by irradiating the laser beam through the mask having the circular slit, the rectangular seed crystal has a rectangular opening (rectangular slit) from an oblique direction. As in the case where the seed crystal is stretched by irradiating laser light through a mask, the laser crystallization method using the laser crystallization apparatus is performed simultaneously in two directions (for example, 1X + direction and 1Y + direction) in the same quadrant. The seed crystal may be extended.

  In the mask 15c shown in FIG. 44, the mask element 21-1 and the mask element 22-1 correspond to the seed crystal formation mask elements, and two seed crystals could be generated simultaneously by the mask 15c. However, the present invention is not limited to this. Two or more seed crystals in the X-axis direction and / or two or more seed crystals in the Y-axis direction are simultaneously formed by appropriately changing the number of mask elements and the arrangement of slits in each mask element. You can also.

  That is, the seed crystal forming mask element group is arranged along the moving direction described above, the first forming mask element having one or more openings extending in the first direction, and the opening extending in the second direction. And a second formation mask element having one or more of the above.

  Each embodiment disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is the figure which showed schematic structure of the laser crystallization apparatus. It is sectional drawing which showed the cross section of the to-be-processed object. It is the figure which showed the structure of the mask for forming a square crystal. The centroid P of the seed crystal formed by the first irradiation using the mask element for seed crystal formation and the second irradiation using another mask element for seed crystal formation after the mask 15 has moved by the distance M It is the figure which showed the XY rectangular coordinate system made into an origin. It is a top view of a to-be-processed object in the case of crystallizing by 1st irradiation using the slit 1-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 2nd irradiation using the slit 2-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 3rd irradiation using the slit 3-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 4th irradiation using the slit 3-2a of the mask shown in FIG. It is a top view of a to-be-processed object at the time of crystallizing by 5th irradiation using the slit 3-3a of the mask shown in FIG. It is a top view of a to-be-processed object at the time of crystallizing by 6th irradiation using the slit 4-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 7th irradiation using the slit 4-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 8th irradiation using the slit 4-3a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 9th irradiation using the slit 5-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 10th irradiation using the slit 5-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 11th irradiation using the slit 5-3a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 12th irradiation using the slit 6-1a of the mask shown in FIG. It is a top view of a to-be-processed object at the time of crystallizing by 13th irradiation using the slit 6-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 14th irradiation using the slit 6-3a of the mask shown in FIG. It is the figure which showed the relationship between a seed crystal and the square crystal finally formed. It is the figure which showed the structure of the other mask for forming a square crystal. It is a top view of a to-be-processed object in the case of crystallizing by 1st irradiation using the slit 1-1a of the mask shown in FIG. FIG. 21 is a top view of an object to be processed when crystallization is performed by second irradiation using the slit 2-1a of the mask shown in FIG. FIG. 21 is a top view of an object to be processed when crystallization is performed by third irradiation using the slit 3-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 4th irradiation using the slit 4-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 5th irradiation using the slit 3-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 6th irradiation using the slit 4-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 7th irradiation using the slit 3-3a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 8th irradiation using the slit 4-3a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 9th irradiation using the slit 5-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 10th irradiation using the slit 6-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 11th irradiation using the slit 5-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 12th irradiation using the slit 6-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 13th irradiation using the slit 5-3a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 14th irradiation using the slit 6-3a of the mask shown in FIG. It is the figure which showed the structure of the further another mask for forming a square crystal. It is a top view of a to-be-processed object in the case of crystallizing by 1st irradiation using the slit 11-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 2nd irradiation using the slit 12-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 3rd irradiation using the slit 13-1a and the slit 14-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 4th irradiation using the slit 13-2a and slit 14-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 5th irradiation using the slit 13-3a and the slit 14-3a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 6th irradiation using the slit 15-1a and the slit 16-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 7th irradiation using the slit 15-2a and slit 16-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 8th irradiation using the slit 15-3a and slit 16-3a of the mask shown in FIG. It is the figure which showed the structure of the further another mask for forming a square crystal. It is a top view of a to-be-processed object in the case of crystallizing by 1st irradiation using the slit 21-1a and slit 21-1-b of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 2nd irradiation using the slit 22-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 3rd irradiation using the slit 23-1a and the slit 23-1b of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 4th irradiation using the slit 23-2a and slit 23-2b of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 5th irradiation using the slit 24-1a and the slit 24-1b of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 6th irradiation using the slit 24-2a and slit 24-2b of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 7th irradiation using the slit 24-3a and slit 24-3b of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 8th irradiation using the slit 25-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 9th irradiation using the slit 25-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 10th irradiation using the slit 25-3a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 11th irradiation using the slit 26-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 12th irradiation using the slit 26-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 13th irradiation using the slit 26-3a of the mask shown in FIG. After forming a square crystal in the first crystallization region partway, the second crystallization region is subjected to crystallization by first irradiation using the slit 1-1a of another mask. It is a top view of a thing. It is a top view of a to-be-processed object in the case of crystallizing by 2nd irradiation using the slit 2-1a of said other mask. It is a top view of a to-be-processed object in the case of crystallizing by 3rd irradiation using the slit 3-1a of said other mask. It is a top view of a to-be-processed object at the time of crystallizing by 4th irradiation using the slit 3-2a of said other mask. It is a top view of a to-be-processed object in the case of crystallizing by 5th irradiation using the slit 4-1a of said other mask. It is a top view of a to-be-processed object in the case of crystallizing by 6th irradiation using the slit 4-2a of said other mask. It is a top view of a to-be-processed object at the time of crystallizing by 7th irradiation using the slit 4-3a of said other mask. It is a top view of a to-be-processed object in the case of crystallizing by 8th irradiation using the slit 5-1a of said other mask. It is a top view of a to-be-processed object at the time of crystallizing by 9th irradiation using the slit 5-2a of said other mask. It is a top view of a to-be-processed object at the time of crystallizing by 10th irradiation using the slit 5-3a of said other mask. It is a top view of a to-be-processed object at the time of crystallizing by 11th irradiation using the slit 6-1a of said other mask. It is a top view of a to-be-processed object in the case of crystallizing by 12th irradiation using the slit 6-2a of said other mask. It is a top view of a to-be-processed object at the time of crystallizing by 13th irradiation using the slit 6-3a of said other mask. It is the figure which showed the structure of the mask for forming a square crystal based on other embodiment. FIG. 72 is a top view of an object to be processed when crystallization is performed by first irradiation using the slit 1-1a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by second irradiation using the slit 2-1a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by third irradiation using the slit 3-1a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by fourth irradiation using the slit 4-1a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by fifth irradiation using the slit 5-1a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by sixth irradiation using the slit 6-1a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by seventh irradiation using the slit 3-2a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by eighth irradiation using the slit 4-2a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by ninth irradiation using the slit 5-2a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by tenth irradiation using the slit 6-2a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by eleventh irradiation using the slit 3-3a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by twelfth irradiation using the slit 4-3a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by thirteenth irradiation using the slit 5-3a of the mask shown in FIG. 71. FIG. 72 is a top view of an object to be processed when crystallization is performed by 14th irradiation using the slit 6-3a of the mask shown in FIG. 71. It is the figure which showed the structure of the other mask for forming a square crystal. It is a top view of a to-be-processed object in the case of crystallizing by 1st irradiation using the slit 11-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 2nd irradiation using the slit 12-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 3rd irradiation using the slit 13-1a and the slit 14-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 4th irradiation using the slit 15-1a and the slit 16-1a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 5th irradiation using the slit 13-2a and the slit 14-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 6th irradiation using the slit 15-2a and slit 16-2a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 7th irradiation using the slit 13-3a and slit 14-3a of the mask shown in FIG. It is a top view of a to-be-processed object in the case of crystallizing by 8th irradiation using the slit 15-3a and slit 16-3a of the mask shown in FIG. It is the figure which showed schematic structure of the laser crystallization apparatus which concerns on other embodiment. It is the figure which showed the conventional mask. It is the figure which showed the growth state of the crystal | crystallization in the process of growing a crystal using the said conventional mask, (a) is the figure which showed the irradiation pattern of the laser beam formed on a board | substrate by the said mask, b) is a view showing a crystal formed on a substrate by laser light having the irradiation pattern shown in (a), and (c) is a length of the mask in the direction of the arrow of (a) with respect to the substrate. It is the figure which showed the crystal | crystallization formed on a board | substrate at the time of irradiating a laser beam after moving only relatively M, (d) is a laser after moving a mask further only by length M. It is the figure which showed the crystal | crystallization formed on a board | substrate in the case of irradiating light, (e) is a figure on the board | substrate in the case of irradiating a laser beam after moving a mask by the length M further relatively. It is the figure which showed the crystal | crystallization formed. . 97 is a diagram showing the state of crystals grown in the region on the substrate shown in FIG. 97 in association with FIG. 97, and (a) is a diagram showing crystals formed in the region by the first irradiation. (B) is the figure which showed the crystal | crystallization formed in the said area | region by 2nd irradiation, (c) is the figure which showed the crystal | crystallization formed in the said area | region by 3rd irradiation, (d) It is the figure which showed the crystal | crystallization formed in the said area | region by 4 irradiation. It is the figure which showed the other conventional mask. FIG. 99 is a diagram illustrating a crystal growth state in the process of growing a crystal using the mask of FIG. 99, and (a) is a diagram illustrating an irradiation pattern of a laser beam formed on the substrate by the mask; (B) is the figure which showed the crystal | crystallization formed on a board | substrate with the laser beam which has the irradiation pattern shown to (a), (c) is the said mask in the direction of the arrow of (a) with respect to a board | substrate. It is the figure which showed the crystal | crystallization formed on a board | substrate at the time of irradiating a laser beam after moving only by the length M, (d) is a further relative movement of the said mask only by the length M. It is the figure which showed the crystal | crystallization formed on a board | substrate in the case of irradiating with a laser beam after having been made, (e) is irradiated with the laser beam after moving further relative to the said mask and length M further. On the substrate 80 in the case It is a diagram showing a crystal made. FIG. 100 is a diagram showing the state of crystals grown in the region on the substrate shown in FIG. 100 in association with FIG. 100, and (a) is a diagram showing crystals formed in the region by the first irradiation. (B) is the figure which showed the crystal | crystallization formed in the said area | region by 2nd irradiation, (c) is the figure which showed the crystal | crystallization formed in the said area | region by 3rd irradiation, (d) It is the figure which showed the crystal | crystallization formed in the said area | region by 4 irradiation. FIG. 100 is a diagram showing a crystal formed by the first irradiation when the mask of FIG. 99 is used. FIG. 99 is a diagram showing a crystal formed by the second irradiation when the mask of FIG. 99 is used. FIG. 100 is a diagram showing a crystal formed by third irradiation when the mask of FIG. 99 is used. FIG. 100 is a diagram showing a crystal formed by the fourth irradiation when the mask of FIG. 99 is used. It is the figure which showed the relationship between a seed crystal and the square crystal finally formed. It is the figure which showed the XY orthogonal coordinate system which makes the origin the centroid P of the seed crystal formed by the said 1st irradiation and the said 2nd irradiation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,100 Laser crystallization apparatus, 10, 30 Laser light oscillator, 15, 15a, 15b, 15c, 150, 150a Mask, 18 stages, 19 Control apparatus, 20 To-be-processed object.

Claims (36)

A mask for forming an irradiation pattern on the object to be processed by irradiating a laser beam to the object to be processed that has an opening and moves relatively through the opening,
A seed crystal forming mask element group and a seed crystal stretching mask element group arranged along the moving direction,
An opening of the mask element group for seed crystal formation is arranged so that a seed crystal surrounded by a substantially closed-loop crystal grain boundary is formed by the laser light irradiation,
In the XY orthogonal coordinate system having the specific position in the seed crystal as the origin, k is a natural number of 1 to 4, the X axis positive direction in the kth quadrant is kX +, the X axis negative direction is kX−, Y If the positive axis direction is kY + and the negative Y axis direction is kY−,
The substantially closed-loop crystal grains formed by controlling the irradiation timing of the laser beam irradiated through the seed crystal stretching mask element group following the seed crystal forming mask element group and the movement control. The opening of the mask element group for seed crystal extension is formed so that the seed crystal surrounded by the boundary extends in each direction of 1X +, 1Y +, 2X−, 2Y +, 3X−, 3Y−, 4X +, and 4Y−. The mask that has been placed.   At least one of the two directions 1Y + and 2Y +, the two directions 2X- and 3X-, the two directions 3Y- and 4Y-, and the two directions 1X + and 4X + 2. The mask according to claim 1, wherein an opening of the seed crystal stretching mask element group is disposed so as to simultaneously stretch the seed crystal.   The seed crystal stretching mask element group has an X-axis positive direction as X +, an X-axis negative direction as X-, a Y-axis positive direction as Y +, and a Y-axis negative direction as Y-, and n is a natural number of 1 or more. A fourth n-3 extension mask element having a fourth n-3 opening for extending the seed crystal in the Y + direction, and a fourth n-2 opening for extending the seed crystal in the Y- direction. A 4n-2 stretch mask element having a portion, a 4n-1 stretch mask element having a 4n-1 opening for stretching the seed crystal in the X + direction, and the seed crystal in the X- direction. A mask according to claim 1 or 2, comprising a fourth n stretch mask element having a fourth n opening for stretching. The openings of the fourth n-3 opening are arranged in parallel regardless of the value of n,
Each opening of the fourth n-2 opening is arranged in parallel regardless of the value of n,
Each opening of the fourth n-1 opening is arranged in parallel regardless of the value of n,
4. The mask according to claim 3, wherein the openings of the fourth n opening are arranged in parallel regardless of the value of n. 5. When s is a natural number equal to or greater than 1 and the irradiation pattern formed on the substrate by the sth opening of the sth expansion mask element is the sth irradiation pattern,
The first irradiation pattern when the value of n is 1 overlaps the seed crystal so as to include at least a part of the crystal grain boundaries of the first quadrant and the second quadrant,
The second irradiation pattern when the value of n is 1 overlaps with the seed crystal so as to include at least a part of the crystal grain boundaries in the third quadrant and the fourth quadrant,
The third irradiation pattern when the value of n is 1 overlaps with the seed crystal so as to include at least a part of the crystal grain boundaries of the first quadrant and the fourth quadrant,
In the fourth irradiation pattern when the value of n is 1, the first to fourth openings are arranged so as to overlap the seed crystal so as to include at least part of the crystal grain boundaries in the second quadrant and the fourth quadrant. The mask according to claim 4, wherein For each mask element of the 4n-3 expanded mask element, the 4n-2 expanded mask element, the 4n-1 expanded mask element, and the 4n expanded mask element, the mask element when the value of n is k is k The mask element when the value of n is k + 1 is the (k + 1) th mask element, the opening of the kth mask element is the kth opening, and the k + 1th mask element And the center of the k-th opening in the first direction is the k-th center line in the first direction, and the center of the k-th opening in the second direction. If the line is the kth centerline in the second direction,
With respect to the 4n-3 extended mask element, the (k + 1) th mask element is disposed on the opposite side of the seed crystal formation mask element group with respect to the kth mask element, and the (k + 1) th opening. A portion of the portion overlaps the kth center line in the first direction on the one direction side in the second direction;
With respect to the 4n-2 stretched mask element, the (k + 1) th mask element is disposed on the opposite side to the seed crystal formation mask element group with respect to the kth mask element, and the (k + 1) th opening. A portion of the portion overlaps the kth center line in the first direction on the other direction side of the second direction;
Regarding the 4n-1 extended mask element, the (k + 1) th mask element is disposed on the opposite side of the seed crystal forming mask element group with respect to the kth mask element, and the (k + 1) th opening. A portion of the portion overlaps the kth center line in the second direction on the one direction side in the first direction;
With respect to the 4nth extended mask element, the (k + 1) th mask element is disposed on the opposite side of the seed crystal forming mask element group with respect to the kth mask element, and the k + 1th opening portion is provided. The mask according to claim 5, wherein a part of the mask overlaps with the kth center line in the second direction on the other direction side in the first direction.   The 4n-3 expanded mask element, the 4n-2 expanded mask element, the 4n-1 expanded mask element, and the 4n expanded mask element are arranged in this order regardless of the value of n. The mask according to claim 6.   The fourth n-3 stretched mask element, the fourth n-1 stretched mask element, the fourth n-2 stretched mask element, and the fourth n stretched mask element are arranged in this order regardless of the value of n. The mask according to claim 6, wherein   The kth mask element for the 4n-3 stretched mask element, the k + 1th mask element for the 4n-3 stretched mask element, and the kth mask element for the 4n-2 stretched mask element. A mask element, the k + 1th mask element for the 4n-2 stretched mask element, the kth mask element for the 4n-1 stretched mask element, and the 4n-1 stretched mask element. The k + 1th mask element, the kth mask element for the 4n expanded mask element, and the k + 1th mask element for the 4n expanded mask element, regardless of the value of k, The mask according to claim 6 arranged in order.   The k-th mask element for the 4n-3 stretched mask element, the k-th mask element for the 4n-2 stretched mask element, and the k + 1-th for the 4n-3 stretched mask element. A mask element, the k + 1th mask element for the 4n-2 stretched mask element, the kth mask element for the 4n-1 stretched mask element, and the k for the 4n stretched mask element. The k + 1th mask element for the 4n-1 expanded mask element, and the k + 1th mask element for the 4n expanded mask element, regardless of the value of k. The mask according to claim 6 arranged in order.   The kth mask element for the 4n-3 stretched mask element, the kth mask element for the 4n-2 stretched mask element, and the kth mask element for the 4n-1 stretched mask element. A mask element, the kth mask element for the 4n expanded mask element, the k + 1th mask element for the 4n-3 expanded mask element, and the k + 1 for the 4n-2 expanded mask element. The k + 1th mask element for the 4n-1 expanded mask element, and the k + 1th mask element for the 4n expanded mask element, regardless of the value of k. The mask according to claim 6 arranged in order.   The mask element group for extending the seed crystal extends a second n−1 A opening for extending the seed crystal in the Y + direction and the seed crystal in the Y− direction, where n is a natural number of 1 or more. A second n-1 stretched mask element having a 2n-1 B opening for forming the second crystal, a second n A opening for stretching the seed crystal in the X + direction, and the seed crystal in the X-direction. 3. A mask according to claim 1 or 2, comprising a second n stretch mask element having a second n B opening for stretching. The openings of the (2n-1) th A openings are arranged in parallel regardless of the value of the n,
Each opening of the 2n-1 B opening is arranged in parallel regardless of the value of n, and is arranged in parallel to the 2n-1 A opening,
The openings of the second n A openings are arranged in parallel regardless of the value of n,
The openings of the second n B openings are arranged in parallel with each other regardless of the value of the n, and are arranged in parallel with the second n A openings. mask. t is a natural number of 1 or more, and the irradiation pattern formed on the substrate by the tth A opening of the tth extension mask is the irradiation pattern formed on the substrate by the tA irradiation pattern and the tth B opening of the tth extension mask. When the irradiation pattern formed in the tB irradiation pattern is
The first A irradiation pattern when the value of n is 1 overlaps with the seed crystal so as to include at least a part of the grain boundaries of the first quadrant and the second quadrant,
The 1B irradiation pattern when the value of n is 1 overlaps with the seed crystal so as to include at least a part of the crystal grain boundaries in the third and fourth quadrants,
The second A irradiation pattern when the value of n is 1 overlaps with the seed crystal so as to include at least part of the crystal grain boundaries of the first quadrant and the fourth quadrant,
In the second B irradiation pattern when the value of n is 1, an opening is arranged so as to overlap with the seed crystal so as to include at least a part of the crystal grain boundary in the second quadrant and the fourth quadrant. The mask according to claim 13. Regarding the second n-1 expanded mask element and the second n expanded mask element, the mask element when the value of n is k is the kth mask element, and the mask element when the value of n is k + 1 is k + 1 as the mask element,
Further, the two openings of the k-th mask element are k-th A openings and k-th B openings, and the two openings of the k + 1-th mask element are k + 1-th A openings. The opening and the (k + 1) th B opening,
Further, the center line in the first direction of the kth A opening is the kth A centerline in the first direction, and the centerline in the second direction of the kth A opening is in the second direction. The k-th A center line in two directions, the center line in the first direction of the k-th B opening, the k-th B center line in the first direction, and the k-th B opening If the center line in the second direction is the kth B center line in the second direction,
With respect to the 2n-1 stretched mask element, the (k + 1) th mask element is arranged on the opposite side of the seed crystal forming mask element group with respect to the kth mask element, and the (k + 1) th A Part of the opening overlaps the k-th A center line in the first direction on the one direction side in the second direction, and part of the k + 1-th B opening corresponds to the first direction. Overlapping the kth B centerline in the first direction on the other direction side in two directions,
Regarding the second n-th stretched mask element, the (k + 1) th mask element is disposed on the opposite side of the seed crystal forming mask element group with respect to the kth mask element, and the (k + 1) th A opening. A part of the portion overlaps the kth A center line in the second direction on the one direction side of the first direction, and a part of the (k + 1) th B opening is in the first direction. The mask according to claim 14, wherein the mask overlaps with the kth B center line in the second direction on the other facing side of the mask.   The kth mask element for the 2n-1 stretched mask element, the k + 1th mask element for the 2n-1 stretched mask element, and the kth mask element for the 2nn stretched mask element. The mask according to claim 15, wherein the (k + 1) th mask element for the second n expanded mask elements is arranged in this order regardless of the value of k.   The kth mask element for the 2n-1 stretched mask element, the kth mask element for the 2nn stretched mask element, and the k + 1th mask element for the 2n-1 stretched mask element. The mask according to claim 15, wherein the (k + 1) th mask element for the second n expanded mask elements is arranged in this order regardless of the value of k.   The seed crystal formation mask element group includes a first mask element having a first opening extending in the first direction and a second opening extending in the second direction, which are arranged along the moving direction. 18. A mask according to any one of the preceding claims, comprising a second mask element.   The seed crystal forming mask element group includes a first forming mask element arranged in the moving direction and having one or more openings extending in the first direction, and an opening extending in the second direction. 19. A mask according to any one of the preceding claims, comprising two or more second forming mask elements.   The opening of each mask element in the mask element group for seed crystal formation and each opening of each mask element in the mask element group for extending the seed crystal are rectangular. The mask according to item.   20. Each opening of each mask element in the seed crystal forming mask element group is circular, and each opening of each mask element in the seed crystal extending mask element group is rectangular. The mask of any one of these.   The mask according to any one of claims 1 to 21, wherein the second direction is a direction perpendicular to the first direction.   At least one of the two directions 1X + and 1Y +, the two directions 2X− and 2Y +, the two directions 3X− and 3Y−, and the two directions 4X + and 4Y− 2. The mask according to claim 1, wherein an opening of the seed crystal stretching mask element group is disposed so as to simultaneously stretch the seed crystal. A mask according to any one of claims 1 to 23;
A laser beam irradiation apparatus for irradiating the laser beam;
A moving device for moving the object to be processed relative to the mask;
A laser crystallization apparatus comprising: a control device that controls the irradiation and the movement.   25. The laser according to claim 24, wherein the amount of energy of the laser beam irradiated by the laser beam irradiation device is an energy amount for melting the object to be processed on the substrate in the thickness direction of the object to be processed. Crystallizer. When the laser beam is a first laser beam, the laser beam irradiation apparatus further includes a second laser beam irradiation device that irradiates the workpiece with a second laser beam different from the first laser beam.
The laser crystallization apparatus according to claim 24 or 25, wherein the second laser beam is irradiated to a region irradiated with the first laser beam together with the irradiation of the first laser beam. A laser crystallization method for forming crystal grains by irradiating an object to be moved relatively moving laser light through an opening,
A seed crystal forming step for forming a seed crystal surrounded by a continuous crystal grain boundary or a crystal grain boundary partially discontinuous on the workpiece;
In the XY orthogonal coordinate system with the specific position of the seed crystal as the origin, the X-axis positive direction is X +, the X-axis negative direction is X-, the Y-axis positive direction is Y +, and the Y-axis negative direction is Y-. And a seed crystal stretching step for stretching the seed crystal to X +, X−, Y +, and Y−, where X + is a relative moving direction of the workpiece. Method.   28. The laser crystallization method according to claim 27, wherein, in the seed crystal stretching step, the crystal stretching in Y + and Y- is performed after the crystal stretching in X + and X- is completed.   28. The laser crystallization method according to claim 27, wherein in the seed crystal stretching step, crystal stretching in X + and X- and crystal stretching in Y + and Y- are alternately performed.   28. The laser crystallization method according to claim 27, wherein in the seed crystal stretching step, X + stretching and X- stretching are simultaneously performed. In the seed crystal formation step, at least two seed crystals are formed,
In the seed crystal stretching step, two crystals in the middle of stretching obtained by stretching the formed seed crystal in a predetermined direction, the two crystals adjacent in the predetermined direction being last in the predetermined direction. The laser crystallization method according to any one of claims 27 to 30, wherein when the stretching is performed, stretching is simultaneously performed using one opening. The seed crystal forming step;
The seed crystal stretching step;
32. The laser crystallization method according to any one of claims 27 to 31, wherein a moving step of relatively moving the object to be processed in a direction perpendicular to the moving direction is repeated.   In the seed crystal stretching step, a first crystal in the middle of stretching obtained by stretching the formed seed crystal in the moving direction and the vertical direction, and a second halfway in the middle of stretching adjacent to the vertical direction. 31. The method according to any one of claims 27 to 30, wherein the first crystal and the second crystal are simultaneously stretched using one opening when performing a final stretching of the crystal in the vertical direction. The laser crystallization method as described. A laser crystallization method for forming crystal grains by irradiating an object to be moved relatively moving laser light through an opening,
A seed crystal forming step for forming a seed crystal surrounded by a continuous crystal grain boundary or a crystal grain boundary partially discontinuous on the workpiece;
In the XY orthogonal coordinate system with the specific position of the seed crystal as the origin, the X-axis positive direction is X +, the X-axis negative direction is X-, the Y-axis positive direction is Y +, and the Y-axis negative direction is Y-. And the relative movement direction of the workpiece is X +, the seed crystal is X + and Y + in the first quadrant in the coordinate system, and X− in the second quadrant in the coordinate system. And Y +, a seed crystal extension step for extending X− and Y− in the third quadrant in the coordinate system, and X + and Y− in the fourth quadrant in the coordinate system, Laser crystallization method.   35. A crystal material comprising crystal grains formed by the laser crystallization method according to any one of claims 27 to 34.   36. A semiconductor device comprising a transistor having a channel region in the crystal grain of the crystal material according to claim 35.

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