JP2007317809A - Laser irradiator, and laser processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser irradiator in which a high quality product can be produced at a high throughput. <P>SOLUTION: The laser irradiator has a laser light source; a stage which holds a processing board at a position where laser beams emitted from the laser light source are entered, and moves the processing board to a direction parallel to its irradiating face; a transmission region limiter which is arranged on a path of the leaser beams between the laser light source and the stage, and in which a transmission region which transmits the laser beams is defined within a shading region shading the laser beams; an image formation optical system for forming the image of the laser beams which have transmitted the transmission region of the transmission region limiter on the irradiating face of the processing board held by the stage; a moving device for moving the transmission region limiter to a direction vertical to an optical axis of the image formation optical system; an image formation point in which a virtual point fixed into the transmission region of the transmission region limiter forms an image on the irradiating face of the processing board held by the stage; and a controller for controlling the stage and moving device, so that a relative position to the processing board does not change. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for irradiating a laser beam and a method for performing processing by irradiating a laser beam.

  A technique is known in which impurities are injected into a semiconductor substrate, for example, a circular silicon wafer, and the injected impurities are activated by irradiating a laser beam formed in a rectangular shape or a line shape. These long laser beams in one direction are irradiated onto the silicon wafer such that both ends in the length direction move on, for example, scribe lines of a plurality of chips defined in a lattice shape on the silicon wafer. (For example, refer to Patent Document 1.) Thereby, the annealing effect in the chip can be made uniform.

  The silicon wafer is held on a holding table such as an XY stage. Avoiding the irradiation of the laser beam to the XY stage and irradiating only the circular silicon wafer with the rectangular or line shaped beam, the beam is not irradiated on the silicon wafer and annealing is not performed. A region arises. This can be a problem particularly when a long beam is irradiated.

  As a countermeasure against this, for example, a method of covering the outer edge of the silicon wafer and the XY stage with a jig and irradiating a laser beam can be considered. However, in this method, there is a possibility that metal contamination and particle generation problems may occur on the silicon wafer due to the laser beam applied to the jig.

JP 2004-152888 A

  An object of the present invention is to provide a laser irradiation apparatus capable of manufacturing a high-quality product with high throughput.

  Another object of the present invention is to provide a laser processing method capable of producing a high-quality product with high throughput.

  According to one aspect of the present invention, a laser light source that emits a laser beam and a processing target substrate are held at a position where the laser beam emitted from the laser light source is incident, and the processing target substrate is parallel to the irradiated surface. And a transmission region that is arranged on a laser beam path between the laser light source and the stage and in which a transmission region that transmits the laser beam is defined in a light shielding region that blocks the laser beam A limiter, an imaging optical system that forms an image of the laser beam transmitted through the transmission region of the transmission region limiter on the irradiated surface of the processing target substrate held by the stage, and the transmission region limiter, A moving device that moves in a direction perpendicular to the optical axis of the imaging optical system, and a virtual point fixed in the transmission region of the transmission region limiter are irradiated on the processing target substrate held on the stage. And imaging point for imaging the surface, so that the relative position between the processed substrate is not changed, the laser irradiation device is provided with a controller for controlling said stage and said mobile device.

  When laser annealing is performed using this laser irradiation apparatus, for example, the entire chip formation region of the semiconductor substrate can be annealed while preventing generation of particles. For this reason, a high-quality semiconductor device can be manufactured with high throughput.

  According to another aspect of the present invention, a laser beam transmitted through the transmission region is transmitted through a transmission region limiter in which a transmission region that transmits the laser beam is defined in a light-shielding region that blocks the laser beam. The virtual point fixed in the transmission region of the transmission region limiter while the laser beam is incident on the processing target substrate under the condition of forming an image on the irradiated surface of the processing target substrate, A laser processing method comprising a step of moving the substrate to be processed and the transmission region limiter in conjunction with each other so that the relative position between the image forming point imaged on the irradiated surface and the substrate to be processed does not change. Provided.

  This laser processing method can be implemented using, for example, the above-described laser irradiation apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, the laser irradiation apparatus which can manufacture a high quality product with a high throughput can be provided.

  In addition, according to the present invention, it is possible to provide a laser processing method capable of manufacturing a high-quality product with high throughput.

  FIG. 1 is a schematic diagram illustrating a laser irradiation apparatus according to an embodiment. The laser irradiation apparatus includes a processing chamber 40, a transfer chamber 82, carry-in / out chambers 83 and 84, a laser light source 71, a homogenizer 72, a transmission region limiting plate 23, an imaging lens system 25, a control device 26, a CCD camera 88, and a video monitor. 89 is comprised.

  The processing chamber 40 and the transfer chamber 82 are connected via a gate valve 85, and the transfer chamber 82 and the carry-in / out chamber 83, and the transfer chamber 82 and the carry-in / out chamber 84 are connected via gate valves 86 and 87, respectively. . Vacuum pumps 91, 92, and 93 are attached to the processing chamber 40 and the loading / unloading chambers 83 and 84, respectively, so that the inside of each chamber can be evacuated.

  A transfer robot 94 is accommodated in the transfer chamber 82. The transfer robot 94 transfers a silicon wafer (processing substrate) between the processing chamber 40 and the loading / unloading chambers 83 and 84.

  A quartz window 38 for transmitting a laser beam is provided on the upper surface of the processing chamber 40. Note that a visible optical glass such as BK7 (borosilicate crown 7) may be used instead of quartz. The laser light source 71 includes, for example, two laser oscillators that output a pulse laser beam and a polarization beam splitter. The pulse laser beams output from the two laser oscillators are combined using a polarization beam splitter and emitted from the laser light source 71. The pulse laser beam emitted from the laser light source 71 passes through the attenuator 76 and enters the homogenizer 72. The homogenizer 72 shapes the cross-sectional shape of the laser beam and makes the intensity in the beam cross-section uniform.

  The laser beam that has passed through the homogenizer 72 passes through the transmission region limiting plate 23 and the imaging lens system 25, passes through the quartz window 38, and is incident on the silicon wafer held on the XY stage 44 in the processing chamber 40. The XY stage 24 can move the transmission region limiting plate 23 in a direction perpendicular to the optical axis direction of the laser beam. The XY stage 44 can move the silicon wafer in a two-dimensional direction parallel to the silicon wafer surface. A control device 26 is connected between the XY stage 24 and the XY stage 44.

  The homogenizer 72, the transmission region limiting plate 23, the XY stage 24, the imaging lens system 25, and the control device 26 will be described in detail with reference to the following drawings.

  The surface of the silicon wafer is photographed by a CCD camera 88, and the surface of the wafer being processed can be observed by a video monitor 89.

  FIG. 2A is a schematic diagram illustrating a characteristic portion of the laser irradiation apparatus according to the embodiment.

  The homogenizer 72 includes the array lens 21 and the condenser 22. As described above, the laser beam emitted from the homogenizer 72 passes through the transmission region limiting plate 23, the imaging lens system 25, and the quartz window 38, and is placed on the XY stage 44 in the processing chamber 40. 27 is incident. A control device 26 is connected between the XY stage 24 and the XY stage 44 in the processing chamber 40.

  The array lens 21 has a large number of microlenses arranged in an array, and has a function of creating a uniform intensity distribution in the beam cross section by dividing the incident beam into a large number of microbeams and superimposing them.

  The condenser 22 guides the incident beam to the imaging lens system 25 with high efficiency and makes the intensity in the beam cross section uniform.

  The homogenizer 72 brings the light intensity distribution in the beam cross section of the laser beam close to uniform at the position where the transmission region limiting plate 23 is disposed.

  The transmissive region limiting plate 23 includes a transmissive region, and cuts the incident laser beam at a portion other than the transmissive region (light shielding region), thereby forming a cross section of the beam into a shape having an outer peripheral shape of the transmissive region. it can.

  The homogenizer 72 and the transmission region limiting plate 23 are arranged at a position where the laser beam 10 focuses on the position of the transmission region limiting plate 23.

  The XY stage 24 is used for moving the transmission area limiting plate 23. The imaging lens system 25 can form an image of the laser beam shaping section on the transmission region limiting plate 23 on the silicon wafer 27. The control device 26 can link the operation of the XY stage 44 in the processing chamber 40 on which the silicon wafer 27 is placed with the operation of the XY stage 24 that is a moving mechanism of the transmission region limiting plate 23. .

  The laser irradiation apparatus according to the embodiment has a structure in which the laser beam formed by the transmission region limiting plate 23 is irradiated to the silicon wafer 27 through the imaging lens system 25. When the structure in which the laser beam immediately after being emitted from the transmission region limiting plate 23 is applied to the silicon wafer 27 is employed, the transmission region limiting plate 23 is irradiated with the laser beam immediately before the silicon wafer 27 depending on the use mode. In some cases, the contamination may be caused by the contact of the transmission region limiting plate 23 with the silicon wafer 27.

  FIG. 2B is a plan view of the silicon wafer 27 placed on the XY stage 44 and is a view seen along the traveling direction (optical axis direction) of the laser beam 10. The silicon wafer 27 has a shape in which a part of an arc is cut into a chord shape from a circular shape having a diameter of 150 mm, for example, in plan view. A portion where a part of the arc is replaced with a string is a so-called orientation flat 27a, which functions as a mark for confirming the crystal orientation of the silicon wafer 27.

  By irradiating the silicon wafer 27 with a laser beam (annealing) using the laser irradiation apparatus according to the embodiment, the silicon wafer 27 can be activated and the silicon film can be crystallized to manufacture a semiconductor device. In the manufacture of a semiconductor device, normally, a semiconductor device (chip) is not formed in a peripheral portion of, for example, 5 mm from the outer periphery of the silicon wafer 27. Therefore, it is not necessary to irradiate the peripheral portion with the laser beam, and it is preferable not to irradiate it in order to prevent contamination. In this figure, the boundary between the peripheral portion where the chip is not formed and the central portion where the chip is formed is indicated by a dotted line. The shape defined by the outer peripheral line of the silicon wafer 27 and the shape defined by the dotted line are similar, for example.

  FIG. 2C is a schematic diagram showing the transmission region limiting plate 23 and an XY stage 24 that is a moving mechanism thereof.

  The transmissive region limiting plate 23 is formed, for example, by coating a dielectric with multiple layers, has a transmissive region (region not coated with a dielectric) 23a that is similar to (including congruent to) the silicon wafer 27, and has an XY stage 24. It is attached to the side of the. Of the outer edge of the transmission region 23a, the portion corresponding to the orientation flat 27a of the silicon wafer 27 is the orientation flat corresponding portion 23b. The XY stage 24 can move the transmission region limiting plate 23 in a direction perpendicular to the traveling direction of the laser beam incident on the transmission region limiting plate 23.

  The laser beam 10 having a cross section that is long in one direction by the array lens 21 and the condenser 22 is incident on the transmission region limiting plate 23. The length direction of the cross-sectional shape of the incident laser beam 10 and the orientation flat corresponding portion 23b of the transmission region 23a are parallel, for example. The laser beam 10 incident on the portion other than the transmission region 23a of the transmission region limiting plate 23 is cut, and the laser beam 10 incident on the transmission region 23a is shaped into a shape having an outer edge shape of the transmission region 23a. In the drawing, the cross-sectional shape of the laser beam 10 emitted from the transmission region limiting plate 23 is shown by hatching. The shape of the shaded portion is imaged on the surface of the silicon wafer 27.

  By moving the transmission region limiting plate 23 through the XY stage 24 in synchronization with the movement of the silicon wafer 27 by the XY stage 44, the central portion of the silicon wafer 27 (the region excluding the peripheral portion where the chip is not formed) Only the region inside the dotted line of the semiconductor wafer 27 shown in 2 (B) can be irradiated with the laser beam.

  A laser processing method (laser annealing method) according to the first embodiment will be described with reference to FIGS.

  Reference is made to FIG. An opening 30a is formed in the resist film 30 by forming a resist film 30 on the surface of the silicon wafer 27 to be annealed, and performing exposure and development. In the first embodiment, a silicon wafer 27 having a circular shape having a diameter of 150 mm and a circular arc partly cut out in a chord shape from a circular shape having a diameter of 150 mm in plan view is used.

  Reference is made to FIG. Using the resist film 30 as a mask, germanium ions are implanted into the surface layer portion of the silicon wafer 27 through the opening 30a. Thereby, the surface layer part of the area | region corresponding to the opening part 30a is amorphized, and the amorphous area | region 31 is formed. Note that the regions to be amorphized are, for example, MOSFET source and drain regions. In the case of making the source and drain regions amorphous, for example, germanium ions are implanted into the regions to be the source and drain regions using the gate electrode of the MOSFET as a mask.

  Reference is made to FIG. Impurities are implanted into the surface layer portion of the silicon wafer 27 using the resist film 30 as a mask. Impurities are, for example, boron (B), phosphorus (P), arsenic (As), and the like. Thereby, the impurity implantation region 32 is formed. Thereafter, the resist film 30 is removed.

Subsequently, the silicon wafer 27 is held on the stage 44 of the laser irradiation apparatus shown in FIG. 1, and the surface of the silicon wafer 27 is irradiated with a laser beam. The laser beam is, for example, a second harmonic of an Nd: YLF laser having a wavelength of 527 nm. The pulse width is, for example, 110 ns, and the energy density per pulse on the surface of the silicon wafer 27 is set to such a size that the surface layer portion of the silicon wafer 27 does not melt, for example, 700 to 800 mJ / cm ² . The energy density per pulse of the laser beam is adjusted so that the temperature of the surface of the silicon wafer 27 does not exceed the melting point (1147 ° C.) of amorphous silicon. The surface of the silicon wafer 27 is heated by the laser beam irradiation, solid phase growth occurs, the amorphous region 31 is recrystallized, and impurities in the impurity implantation region 32 are activated.

  With reference to FIGS. 3D to 3I, a laser beam irradiation method will be described.

  FIG. 3D is a schematic diagram showing the transmission region limiting plate 23 and the XY stage 24 used in the first embodiment. As described above, the transmission region limiting plate 23 has the transmission region 23a similar to the silicon wafer 27 (and the central portion of the silicon wafer 27). In the first embodiment, the transmission region 23a has a shape (a shape congruent with the central portion of the silicon wafer 27) obtained by cutting a circular arc having a diameter of 140 mm from a part of the arc as the orientation flat corresponding portion 23b. The cross-sectional shape of the beam at the position 23 is imaged on the surface of the silicon wafer 27 by using the imaging lens system 25 which is an equal magnification optical system. In the laser beam irradiation process, the laser beam 10 is transmitted through the entire transmission region 23a at least once.

  A laser beam 10 that is long in one direction is incident on the transmission region limiting plate 23. The length of the laser beam 10 is 150 mm, and the width is 0.05 mm. The laser beam 10 has its length direction parallel to the orientation flat corresponding portion 23b (so as to be perpendicular to the center line indicated by the alternate long and short dash line), and the center in the length direction is on the center line. As shown, the light enters the transmission region limiting plate 23. The incident region is on the side opposite to the orientation flat corresponding portion 23b.

  The laser beam 10 is cut by the transmission region limiting plate 23 along one continuous outer edge of the transmission region 23a, and only a portion (shown by hatching in this figure) that has passed through the transmission region 23a is imaged. An image is formed on the silicon wafer 27 by the optical system 25.

  In FIG. 3E, the region on the silicon wafer 27 on which the laser beam 10 formed in the step shown in FIG. The laser beam having a cross-sectional shape formed by the transmission region limiting plate 23 enters a region on the central portion of the silicon wafer 27 corresponding to the region of the transmission region 23a through which the laser beam is transmitted. As described above, the silicon wafer 27 is placed on the XY stage 44 in the processing chamber.

  Reference is made to FIG. The XY stage 24 moves the transmissive region limiting plate 23, for example, 0.01 mm parallel to the center line of the transmissive region 23a to the upper side of the figure. As a result, the laser beam 10 is incident on the transmission region limiting plate 23 at a position 0.01 mm below the incident position shown in FIG. 3D along the beam width direction. The incident laser beam 10 is cut along the outer edge of the transmission region 23a by the transmission region limiting plate 23, and only the portion (shown by oblique lines in this figure) that has passed through the transmission region 23a is an imaging optical system. 25 forms an image on the silicon wafer 27.

  Reference is made to FIG. The silicon wafer 27 is moved 0.01 mm upward in the figure in parallel with the center line of the silicon wafer 27 in conjunction with the movement of the transmission region limiting plate by the XY stage 44. In FIG. 3G, a region on the silicon wafer 27 on which the laser beam 10 formed in the step shown in FIG. The laser beam having a cross-sectional shape formed by the transmission region limiting plate 23 enters the center of the silicon wafer 27 corresponding to the region of the transmission region 23a through which the laser beam has been transmitted. As described above, the transmission point is set so that the virtual point fixed in the transmission region 23 a of the transmission region limiting plate 23 does not change the relative position between the imaging point on the surface of the silicon wafer 27 and the silicon wafer 27. The limiting plate 23 and the silicon wafer 27 are interlocked.

  80% of the area indicated by hatching in FIG. 3G overlaps the area indicated by hatching in FIG. That is, the laser beam is irradiated onto the silicon wafer 27 at an overlap rate of 80%. As described above, the transmission region limiting plate is moved by 0.01 mm in parallel with the center line of the transmission region by the XY stage 24, and the silicon wafer 27 is moved along the center line by the XY stage 44 in conjunction therewith. In each direction, the laser beam is irradiated onto the silicon wafer 27 through the transmission region by the movement of 0.01 mm, so that the laser beam cut and formed by the transmission region limiting plate is formed at the center of the silicon wafer 27. The entire area is irradiated.

  Reference is made to FIG. A hatched portion in the drawing is a shaped cross section of the laser beam 10 cut along the outer edge of the transmission region 23a including the orientation flat corresponding portion 23b.

  Reference is made to FIG. The laser beam having the cross-sectional shape shown by hatching in FIG. 3H is incident on the hatched region in this drawing, and the irradiation of the laser beam is completed. In this way, it is possible to irradiate the entire area of the central portion without irradiating the outer peripheral portion of the silicon wafer 27 with the laser beam.

  A laser processing method (laser annealing method) according to the second embodiment will be described with reference to FIGS.

  Also in the second embodiment, the impurity implantation process described with reference to FIGS. 3A to 3C is performed in the same manner as in the first embodiment. The second embodiment is different from the first embodiment in the size of the silicon wafer to be annealed, the size of the transmission region of the transmission region limiting plate, the size of the laser beam incident on the transmission region limiting plate, and the laser beam irradiation method. And different. The wavelength of the pulse laser beam to be used, the pulse width, and the energy density per pulse on the silicon wafer surface are the same as those in the first embodiment. Also in the second embodiment, an imaging lens system constituting an equal magnification optical system is used.

  The silicon wafer used in the second embodiment has a shape obtained by cutting a circular arc having a diameter of, for example, 200 mm into a chord shape with a partial arc as an orientation flat in a plan view. In addition, the transmission region of the transmission region limiting plate has a circular shape with a diameter of 190 mm and a shape in which a part of the arc is an orientation flat corresponding portion and is not coated with a dielectric (a shape congruent with the central portion of the silicon wafer used in the second embodiment ). Further, in the second embodiment, a laser beam that is long in one direction with a length of 100 mm and a width of 0.1 mm is made incident on the transmission region limiting plate.

  The laser irradiation method in the laser processing method (laser annealing method) according to the second embodiment will be described below.

  Reference is made to FIG. The laser beam 10 having a length of 100 mm and a width of 0.1 mm is incident on the transmission region limiting plate 23 so that the beam passes through the region on the left side of the center line of the transmission region 23a. The laser beam 10 has its length direction parallel to the orientation flat corresponding portion 23b (so that it is perpendicular to the center line of the transmission region 23a), and the right end of the length direction is on the center line. As shown, the light enters the transmission region limiting plate 23. The incident region is on the side opposite to the orientation flat corresponding portion 23b.

  The laser beam 10 is cut along the outer edge of the transmission region 23 a by the transmission region limiting plate 23, and only the portion that has passed through the transmission region 23 a is imaged on the silicon wafer 27 by the imaging optical system 25.

  In FIG. 4B, a region on the silicon wafer 27 on which the laser beam 10 formed in the process shown in FIG. The laser beam having a cross-sectional shape formed by the transmission region limiting plate 23 enters the center of the silicon wafer 27 corresponding to the region of the transmission region 23a through which the laser beam has been transmitted. The right end of the laser beam is irradiated on the center line of the silicon wafer 27. On the surface of the silicon wafer 27, a plurality of scribe lines intersecting each other, for example, orthogonal to each other are defined in a lattice shape. The scribe line is used to divide into individual chips, and is also defined along the center line of the silicon wafer 27, for example.

  Reference is made to FIG. The XY stage 24 moves the transmissive region limiting plate 23, for example, 0.01 mm parallel to the center line of the transmissive region 23a to the upper side of the figure. As a result, the laser beam 10 is incident on the transmission region limiting plate 23 at a position 0.01 mm below the incident position shown in FIG. 4A along the beam width direction. The incident laser beam 10 is cut along the outer edge of the transmission region 23 a by the transmission region limiting plate 23, and only the portion that has passed through the transmission region 23 a is imaged on the silicon wafer 27 by the imaging optical system 25. .

  Reference is made to FIG. The silicon wafer 27 is moved by 0.01 mm to the upper side of the figure in parallel with the center line of the silicon wafer 27 in synchronization with the movement of the transmission region limiting plate 23 by the XY stage 44. In FIG. 4D, a region on the silicon wafer 27 on which the laser beam 10 formed in the process shown in FIG. The laser beam having a cross-sectional shape formed by the transmission region limiting plate 23 enters the center of the silicon wafer 27 corresponding to the region of the transmission region 23a through which the laser beam has been transmitted.

  90% of the area indicated by hatching in FIG. 4D overlaps the area indicated by hatching in FIG. That is, the laser beam is irradiated onto the silicon wafer 27 at a 90% overlap rate. As described above, the transmission region limiting plate is moved by 0.01 mm in parallel with the center line of the transmission region by the XY stage 24, and the silicon wafer 27 is the same along the center line by the XY stage 44 in synchronization therewith. In each direction, the laser beam is irradiated onto the silicon wafer 27 through the transmission region by the movement of 0.01 mm, so that the laser beam cut and formed by the transmission region limiting plate is formed at the center of the silicon wafer 27. The left half area is irradiated.

  Reference is made to FIG. A hatched portion in the drawing is a shaped cross section of the laser beam 10 cut along the outer edge of the transmission region 23a including the left half of the orientation flat corresponding portion 23b.

  Reference is made to FIG. The laser beam having the cross-sectional shape shown by hatching in FIG. 4E is incident on the hatched region in this drawing.

  Reference is made to FIG. By the XY stage 24, the transmission region limiting plate 23 is moved 100 mm, for example, to the left side of the figure perpendicularly to the center line of the transmission region 23a. As a result, the laser beam 10 is incident on the transmission region limiting plate 23 at a position 100 mm to the right of the incident position shown in FIG. 4E along the length direction of the beam. That is, the left end in the length direction of the laser beam 10 passes on the center line.

  Reference is made to FIG. The silicon wafer 27 is moved 100 mm to the left in the figure perpendicularly to the center line of the silicon wafer 27 by the XY stage 44 in conjunction with the movement of the transmission region limiting plate. In FIG. 4H, a region on the silicon wafer 27 on which the laser beam 10 formed in the step shown in FIG.

  Thereafter, the transmission region limiting plate is moved by 0.01 mm in parallel with the center line of the transmission region by the XY stage 24, and in synchronization with this, the silicon wafer 27 is moved in the same direction along the center line by the XY stage 44. The laser beam is moved by 0.01 mm each time, and the laser beam is irradiated onto the silicon wafer 27 through the transmission region, so that the laser beam cut and formed by the transmission region limiting plate is the right half of the central portion of the silicon wafer 27. The area is irradiated.

  Reference is made to FIG. A hatched portion in this drawing is a shaped cross section of the laser beam 10 cut along the outer edge of the transmission region 23a on the opposite side of the orientation flat corresponding portion 23b.

  Reference is made to FIG. The laser beam having the cross-sectional shape shown by hatching in FIG. 4I is incident on the hatched region in this drawing, and the irradiation of the laser beam is completed. In this way, it is possible to irradiate the entire area of the central portion without irradiating the outer peripheral portion of the silicon wafer 27 with the laser beam.

  In the second embodiment, the lengthwise end of the laser beam incident on the silicon wafer moved on the center line of the silicon wafer in addition to the boundary between the central portion and the peripheral portion of the silicon wafer. However, since the scribe line is defined on the center line, the position where the annealing effect becomes non-uniform coincides with the scribe line. For this reason, the annealing effect can be made uniform in the chip.

  In the first embodiment, annealing was performed by irradiating a beam having a length equal to the diameter of the silicon wafer. In the second embodiment, the silicon wafer was irradiated with a beam having a length ½ of the diameter. According to the laser processing method (laser annealing method) according to the embodiment, it is possible to irradiate the entire region with the laser beam without entering the laser beam except for the central portion of the silicon wafer. In consideration of the fact that the conventional laser annealing method is difficult particularly when a large-area beam is used, annealing using a long beam is more effective. Considering what can be done efficiently, the laser processing method (laser annealing method) according to the embodiment preferably uses a laser beam having a length of ¼ or more of the diameter of the silicon wafer, and ½ or more. It would be more preferable to use a laser beam having a length.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these.

  For example, in the embodiment, a silicon wafer having an orientation flat is used, but a silicon wafer having a notch can be similarly applied. In this case, the transmission area of the transmission area limiting plate may be circular.

  In the embodiment, the imaging lens system constituting the equal magnification optical system is used. However, an imaging lens system constituting the enlargement or reduction optical system may be adopted. In the case of an equal magnification optical system, the size of the transmission area of the transmission area limiting plate is almost equal to the size of the silicon wafer, but in the case of an enlargement optical system, the size is smaller than that of the silicon wafer. In the case of an optical system, the size is larger than that of a silicon wafer. Furthermore, a projection optical system having a different enlargement ratio or reduction ratio in the moving direction of the transmission region limiting plate or the silicon wafer (for example, the X direction or Y direction of the XY stage) may be used.

  In the embodiment, a silicon wafer is used as a processing target (annealing target), but a semiconductor substrate having at least a surface layer formed of silicon may be a processing target (annealing target). Furthermore, semiconductor materials other than silicon (for example, GaAs, InSb, Ge, SiC, etc.) can be used.

  It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like are possible.

  In addition to use as a laser annealing method and laser annealing apparatus for manufacturing semiconductor devices, the present invention can be widely used as a processing method and a processing apparatus that perform irradiation with a laser beam.

It is the schematic which shows the laser irradiation apparatus by an Example. (A) is the schematic which shows the characteristic part of the laser irradiation apparatus by an Example, (B) is a top view of the silicon wafer 27 mounted in the XY stage 44, (C) is a permeation | transmission area | region. It is the schematic which shows the limiting plate 23 and the XY stage 24 which is the moving mechanism. (A)-(I) is a figure for demonstrating the laser processing method (laser annealing method) by a 1st Example. (A)-(J) is a figure for demonstrating the laser processing method (laser annealing method) by 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laser beam 21 Array lens 22 Condenser 23 Transmission area limiting plate 23a Transmission area 23b Orientation flat corresponding part 24 XY stage 25 Imaging lens system 26 Controller 27 Silicon wafer 27a Orientation flat 38 Quartz window 40 Processing chamber 44 XY stage 71 Laser light source 72 Homogenizer 76 Attenuator 82 Transport chamber 83, 84 Transport chamber 85-87 Gate valve 88 CCD camera 89 Video monitor 91-93 Vacuum pump 94 Transport robot

Claims (9)

A laser light source for emitting a laser beam;
A stage for holding the processing target substrate at a position where the laser beam emitted from the laser light source is incident, and moving the processing target substrate in a direction parallel to the irradiated surface;
A transmission region limiter disposed on a laser beam path between the laser light source and the stage, wherein a transmission region for transmitting the laser beam is defined in a light shielding region for shielding the laser beam;
An imaging optical system that forms an image of the laser beam transmitted through the transmission region of the transmission region limiter on the irradiated surface of the processing target substrate held by the stage;
A moving device for moving the transmission region limiter in a direction perpendicular to the optical axis of the imaging optical system;
The relative position between the imaging point where the virtual point fixed in the transmission region of the transmission region limiter forms an image on the irradiated surface of the processing target substrate held on the stage and the processing target substrate does not change. Thus, the laser irradiation apparatus which has the control apparatus which controls the said stage and the said moving apparatus.   2. The laser irradiation apparatus according to claim 1, further comprising a homogenizer that makes a light intensity distribution within a beam cross section of a laser beam emitted from the laser light source uniform at a position where the transmission region limiter is disposed.   The laser irradiation apparatus according to claim 2, wherein the homogenizer shapes a beam cross section at a position where the transmission region limiter is arranged into a shape that is long in one direction.   The transmission region of the transmission region limiter includes a beam cross section at a position where the transmission region limiter is disposed, and the moving device is configured such that the light shielding region of the transmission region limiter emits a laser beam emitted from the laser light source. The laser irradiation apparatus according to claim 1, wherein the laser irradiation apparatus has a stroke for moving the transmission region limiter to a position overlapping at least a part of the path.   An image obtained by forming an outer peripheral line of the transmission region of the transmission region limiter on an irradiated surface of the processing target substrate held on the stage is an outer periphery of the processing target substrate held on the stage. The laser irradiation apparatus according to claim 1, wherein the laser irradiation apparatus is disposed along the line and inside the outer peripheral line of the substrate to be processed.   The laser beam that has passed through the transmission region is imaged on the irradiated surface of the substrate to be processed through a transmission region limiter in which a transmission region that transmits the laser beam is defined in the light shielding region that blocks the laser beam. An imaging point at which a virtual point fixed in the transmission region of the transmission region limiter forms an image on an irradiated surface of the processing target substrate while making a laser beam incident on the processing target substrate A laser processing method comprising a step of moving the substrate to be processed and the transmission region limiter in conjunction with each other so that the relative position with respect to the substrate to be processed does not change.   An image obtained by forming an outer peripheral line of the transmission region of the transmission region limiter on the irradiated surface of the processing target substrate is along the outer peripheral line of the processing target substrate and the outer periphery of the processing target substrate. The laser processing method according to claim 6, wherein the laser processing method is disposed inside the line.   Furthermore, the laser processing method of Claim 6 or 7 which has the process of closely approaching the optical intensity distribution of the laser beam in the position where the said permeation | transmission area | region limiter is arrange | positioned.   Furthermore, the laser processing method in any one of Claims 6-8 which has the process of lengthening the beam cross section of the laser beam in the position where the said permeation | transmission area | region limiter is arrange | positioned.

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