JP2017028017A - Laser anneal device and laser anneal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser anneal device capable of detecting local floating of a substrate.SOLUTION: A substrate of anneal object is held at the incident position of a laser beam outputted from a laser light source. Reference light outputted from a reference light source is incident on the substrate. Reflection light of the reference light incident on the substrate surface is received by an image sensor. Based on the detection results of reflection light detected by the image sensor, a controller determines presence or absence of local floating of the substrate from the stage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser annealing apparatus and a laser annealing method.

  In the manufacturing process of an insulated gate bipolar transistor (IGBT), a buffer layer is formed in a deep region of about 1 to 3 μm from the back surface of the substrate. For this reason, it is necessary to activate the dopant ion-implanted in the deep region. Patent Document 1 discloses a laser annealing apparatus suitable for activation annealing of a dopant implanted in a deep region. In this laser annealing apparatus, a pulse current having a top flat time waveform is supplied to a laser diode. Thereby, sufficient annealing can be performed even at a low peak power density.

  In the substrate to be laser annealed, a support member such as a resin film or a glass substrate is attached to a non-annealed surface opposite to the annealed surface irradiated with the laser beam. An adhesive is used for attaching the substrate and the support member. The substrate on which the support member is attached is adsorbed to the stage of the laser annealing apparatus.

JP 2013-74019 A

  Since the substrate to which the support member is attached is adsorbed to the stage, normally, the substrate remains adsorbed to the stage even if the substrate is heated and thermally expanded during laser annealing. However, heat may be transmitted to the adhesive layer to weaken the adhesive force, or the adhesive may be thermally decomposed. When the adhesive strength is weakened or the adhesive is thermally decomposed, the substrate may be locally lifted due to thermal expansion of the substrate. If the substrate is lifted and the substrate surface is out of the range of the focal depth of the laser beam, the annealing condition deviates from an appropriate condition. When the temperature of the substrate decreases, the thermal expansion stops and the part that has been lifted returns to its original state, so it is difficult to determine after annealing whether or not the lift has occurred. For this reason, the defect which was not annealed on appropriate conditions will be overlooked.

  An object of the present invention is to provide a laser annealing apparatus and a laser annealing method capable of detecting local lift of a substrate.

According to one aspect of the invention,
A laser light source for outputting a laser beam;
A stage for holding a substrate to be annealed at a position where the laser beam output from the laser light source is incident;
A reference light source for making reference light incident on the substrate held on the stage;
An image sensor that receives reflected light of the reference light incident on the surface of the substrate;
There is provided a laser annealing apparatus having a control device for determining whether or not the substrate is locally lifted from the stage based on the detection result of the reflected light detected by the image sensor.

According to another aspect of the invention,
Adsorbing a composite substrate including a base member and a substrate to be annealed attached to the base member with an adhesive to the stage in a posture where the base member faces the stage;
A step of causing a laser beam to be incident on the composite substrate adsorbed on the stage and moving an incident position in a plane of the composite substrate;
A step of causing a reference beam to be incident on an incident position of the laser beam on the composite substrate;
Receiving reflected light of the reference light from the composite substrate with an image sensor;
And a step of determining whether or not the substrate is locally lifted from the base member based on a detection result of the reflected light by the image sensor.

  When local lifting occurs on the substrate, the state of reflected light changes. This change in state appears as a change in the detection result of reflected light by the image sensor. Therefore, based on the detection result of the reflected light by the image sensor, it can be determined whether or not the substrate is lifted.

FIG. 1 is a schematic diagram of a laser annealing apparatus according to an embodiment. 2A is a cross-sectional view of the stage of the laser annealing apparatus shown in FIG. 1 and a substrate held on the stage, and FIG. 2B is a view showing a light receiving surface of the image sensor. FIG. 3A is a cross-sectional view of a state where the substrate is locally lifted, and FIG. 3B is a diagram illustrating a light receiving surface of the image sensor. FIG. 4A is a cross-sectional view of another state in which the substrate is locally lifted, and FIG. 4B is a diagram illustrating a light receiving surface of the image sensor. FIG. 5A is a graph showing an example of a temporal change in the position of an incident region of reflected light during annealing, and FIG. 5B is a graph showing an example of a temporal change in the size of the incident region of reflected light during annealing. . FIG. 6 is a flowchart of the laser annealing method according to the embodiment. FIG. 7 is a schematic view of a laser annealing apparatus according to another embodiment. FIG. 8 is a schematic diagram of a detection system of the laser annealing apparatus shown in FIG. FIG. 9 is a conceptual diagram showing the locus of the center of the beam spot of the laser beam in the surface of the substrate. FIG. 10 is a flowchart of a laser annealing method according to another embodiment.

  With reference to FIGS. 1-6, the laser annealing apparatus and laser annealing method by an Example are demonstrated.

  FIG. 1 shows a schematic diagram of a laser annealing apparatus according to an embodiment. The laser light source 10 outputs a pulse laser beam. The beam profile of the pulse laser beam output from the laser light source 10 is made uniform by the uniformizing optical system 11. The pulse laser beam that has passed through the homogenizing optical system 11 enters the dichroic mirror 12. The dichroic mirror 12 reflects light in the wavelength region of the pulse laser beam output from the laser light source 10. The pulse laser beam reflected by the dichroic mirror 12 is converged by the lens 13 and enters the substrate 30 to be annealed. The substrate 30 is held on the stage 31. The substrate 30 is a silicon wafer into which dopant ions are implanted, for example.

  The stage 31 is controlled by the control device 35 and moves the substrate 30 in the in-plane direction. By irradiating the pulse laser beam while moving the substrate 30, the entire surface of the substrate 30 can be annealed.

  The reference light output from the reference light source 20 is incident on the substrate 30 held on the stage 31. The incident position of the reference light is the same as the incident position of the pulse laser beam. Note that the shape and size of the beam spots are not necessarily the same. The reference light is reflected on the surface of the substrate 30. This reflected light enters the image sensor 21. For the image sensor 21, a line sensor, a two-dimensional sensor, or the like is used.

  Next, the configuration of the propagation optical system for reference light and reflected light will be described. The reference light source 20 outputs reference light. For the reference light source 20, for example, a HeNe laser oscillator can be used. The output wavelength of the HeNe laser oscillator is about 633 nm. The laser beam output from the reference light source 20 is transmitted through the half-wave plate 22 and then branched by the polarization beam splitter 23.

  The reference light that has traveled straight through the polarization beam splitter 23 enters the reference light detector 24. The reference light reflected by the polarization beam splitter 23 enters the substrate 30 through the quarter wavelength plate 25, the plurality of total reflection mirrors 26, the dichroic mirror 12, and the lens 13. The dichroic mirror 12 transmits light in the wavelength range of the reference light.

  The reflected light of the reference light incident on the substrate 30 follows the same path in the reverse direction and enters the polarization beam splitter 23. Since the reference light and the reflected light respectively pass through the quarter-wave plate 25, the reflected light travels straight through the polarization beam splitter 23. The reflected light that has traveled straight through the polarization beam splitter 23 enters the image sensor 21.

  The detection result of the reflected light by the image sensor 21 and the measured value of the intensity of the reference light measured by the reference light detector 24 are input to the control device 35. The control device 35 controls the output of the pulse laser beam from the laser light source 10, the movement of the stage 31, and the output of reference light from the reference light source 20. The storage device 36 included in the control device 35 stores a control program and various data necessary for control.

  Through the input device 37, various commands for operating the laser annealing device and data used in the annealing process are input. The response to the input command, the annealing process result, etc. are output to the output device 38. As the output device 38, a liquid crystal display device or the like can be used. As the input device 37, a keyboard, a pointing device, or the like can be used.

  FIG. 2A shows a cross-sectional view of the composite substrate 34 including the stage 31 and the substrate 30. A substrate 30 to be annealed is attached to a base member 32. An adhesive layer 33 is interposed between the substrate 30 and the base member 32. For the adhesive layer 33, for example, a polymer adhesive can be used. The substrate 30 is, for example, a silicon wafer. The base member 32 is, for example, a resin film or a glass substrate. The substrate 30, the base member 32, and the adhesive layer 33 constitute a composite substrate 34.

  The composite substrate 34 is attracted and fixed to the stage 31 with the base member 32 facing the stage 31. As a mechanism for fixing the composite substrate 34, for example, a vacuum chuck can be used. The pulse laser beam L0 output from the laser light source 10 (FIG. 1) is incident on the substrate 30. The reference light L1 output from the reference light source 20 (FIG. 1) enters the same position as the incident position of the pulse laser beam L0. The reflected light L2 of the reference light L1 travels in the reverse direction on the incident path of the reference light L1.

  FIG. 2B shows the light receiving surface 27 of the image sensor 21 (FIG. 1). The reflected light L <b> 2 (FIG. 2A) enters the approximate center of the light receiving surface 27, whereby the incident region 40 of the reflected light L <b> 2 is formed at the approximate center of the light receiving surface 27. A typical incident region (hereinafter referred to as a reference region 41) of the reflected light L2 when no lift occurs on the light receiving surface 27 is defined. When the substrate 30 is not lifted up, the incident region 40 substantially coincides with the reference region 41.

  FIG. 3A shows a cross-sectional view of a state where the substrate 30 is locally lifted. When the pulse laser beam L0 is incident on the substrate 30, a part of the adhesive of the adhesive layer 33 is thermally decomposed. When the bubbles are generated by the thermal decomposition of the adhesive, the substrate 30 is locally lifted from the stage 31. A convex portion 30A is formed at the raised portion. In addition, even when no bubbles are generated, lifting can occur. For example, local lifting may occur due to a decrease in adhesive force due to heating of the adhesive layer 33 and thermal expansion of the substrate 30.

  Due to the local lifting of the substrate 30, the surface of the substrate 30 becomes convex. For this reason, the divergence angle of the reflected light L2 changes compared to the case where no lifting occurs.

  FIG. 3B shows the light receiving surface 27 of the image sensor 21 (FIG. 1) when the lifting occurs (FIG. 3A). Since the spread angle of the reflected light L2 changes, the size of the incident region 40 when the lift occurs is changed from the size of the reference region 41. 3B shows an example in which the incident region 40 is larger than the reference region 41, but the incident region 40 may be smaller than the reference region 41 depending on the configuration of the optical system.

  FIG. 4A shows a cross-sectional view of another state in which the substrate 30 is locally lifted. FIG. 3A shows an example in which the reference light L1 is perpendicularly incident on the substrate 30 and reflected in the vertical direction. In FIG. 4A, the reference light L1 is incident on an inclined portion that is shifted from the top of the convex portion 30A. For this reason, the reference light L1 is reflected in a direction slightly deviated from the vertical direction, and the divergence angle of the reflected light L2 also changes.

  FIG. 4B shows the light receiving surface 27 of the image sensor 21 (FIG. 1). Since the reflected light L2 (FIG. 4A) propagates through a path different from the incident path of the reference light L1, the position of the incident area 40 when the lift occurs is changed from the position of the reference area 41. Furthermore, since the divergence angle of the reflected light L2 also changes, the size of the incident region 40 also changes from the size of the reference region 41. In some cases, the incident region 40 may partially or completely deviate from the light receiving surface 27. When the incident area 40 is partially removed from the light receiving surface 27, the detected value of the intensity of the reflected light L2 is lowered. When the incident area 40 is completely separated from the light receiving surface 27, the detected value of the intensity of the reflected light becomes zero.

  As shown in FIGS. 3A to 4B, it is possible to determine whether or not the substrate 30 is locally lifted from the stage 31 based on the detection result of the reflected light L <b> 2 detected by the image sensor 21. For example, by comparing the position and size of the incident region 40 of the reflected light L2 with the position and size of the reference region 41, the presence or absence of lifting can be determined. Alternatively, the presence or absence of lifting can be determined based on the detected value of the intensity of the reflected light L2.

  When a line sensor is used for the image sensor 21, the position of the incident region 40 is represented by one-dimensional coordinates. The size of the incident region 40 is represented by a dimension in a one-dimensional space, that is, a straight line length.

  FIG. 5A shows an example of a temporal change in the position of the incident region 40 during annealing. When no lifting occurs, the center point of the incident area 40 is located within the allowable range 43. When the lift occurs, the center position of the incident area 40 deviates from the allowable range 43. When the center position of the incident region 40 is out of the allowable range 43, it is determined that local lifting has occurred on the substrate 30.

  FIG. 5B shows an example of the change over time of the size of the incident region 40 during annealing. When the lift does not occur, the size of the incident region 40 is located within the allowable range 44. When the lifting occurs, the size of the incident area 40 deviates from the allowable range 43. When the size of the incident region 40 is out of the allowable range 44, it is determined that local lifting has occurred on the substrate 30.

  When local lifting occurs, the position and size of the incident region 40 change abruptly. Therefore, it is possible to determine whether or not local lifting has occurred based on the change in the position of the incident region 40 or the slope of the change in size. For example, if the inclination of the change in the position or size of the incident region 40 exceeds a certain threshold value, it can be determined that local lifting has occurred.

  FIG. 6 shows a flowchart of a laser annealing method according to the embodiment. Each step is realized by the control device 35 executing a control program. In step S1, the composite substrate 34 (FIG. 2A) is attracted to the stage 31 (FIG. 1). For example, the transfer device carries the composite substrate 34 out of the stock location and transfers it onto the stage 31. After the composite substrate 34 is placed on the stage 31, the vacuum chuck of the stage 31 is operated to attract the composite substrate 34.

  In step S2, the output of the pulse laser beam from the laser light source 10 (FIG. 1), the movement of the stage 31, and the output of the reference light from the reference light source 20 are started. In step S3, it is determined whether the annealing of the entire region of the substrate 30 has been completed. When the annealing of the entire region is finished, the operation of the laser annealing apparatus is finished. An annealing process for the next unprocessed substrate 30 may be started.

  If the annealing of the entire area of the substrate 30 has not been completed, it is determined in step S4 based on the detection result of the reflected light by the image sensor 21 whether or not the local lifting of the substrate 30 has occurred. This determination can be made based on the position or size of the incident region 40 as described with reference to FIG. 5A or 5B. Alternatively, the determination can be made based on the detected value of the intensity of the reflected light.

  When it is determined that the local lift of the substrate 30 has not occurred, the process returns to step S3 and the annealing process is continued. If it is determined that the substrate 30 has been locally lifted, the current reference light incident position information within the surface of the substrate 30 is stored in the storage device 36 in step S6.

  In step S7, the output of the pulse laser beam from the laser light source 10 (FIG. 1), the movement of the stage 31, and the output of the reference light from the reference light source 20 are temporarily stopped. In step S8, the laser output condition is changed. For example, the light intensity of the pulse laser beam is increased and the pulse width is shortened. By adjusting the light intensity and the pulse width, the energy per pulse can be lowered. By reducing the energy per pulse, the temperature rise on the back surface (non-annealed surface) of the substrate 30 can be suppressed. Thereby, the excessive temperature rise of the contact bonding layer 33 is suppressed and it becomes difficult to generate | occur | produce a local lift.

  After changing the laser output condition, the process returns to step S2, and the output of the pulse laser beam from the laser light source 10 (FIG. 1), the movement of the stage 31, and the output of the reference light from the reference light source 20 are resumed.

  In the above-described embodiment, the position information within the surface of the substrate 30 of the location where it is determined that local lifting has occurred is stored (step S6). After the annealing is completed, the position information of the location where it is determined that local lifting has occurred is output to the output device 38. This position information is important information when the substrate 30 after annealing is evaluated.

  Further, in the above embodiment, when it is determined that the lift has occurred, the subsequent laser output conditions are changed to a condition in which the lift is difficult to occur. For this reason, in the area | region where an annealing process is performed after the location determined with the local lift having arisen, generation | occurrence | production of a lift can be suppressed.

  Next, a laser annealing apparatus according to another embodiment will be described with reference to FIGS. Hereinafter, differences from the embodiment shown in FIGS. 1 to 6 will be described, and description of common configurations will be omitted.

FIG. 7 shows a schematic diagram of a laser annealing apparatus according to the present embodiment. This laser annealing apparatus has a first laser light source 51 and a second laser light source 61. A laser diode is used for the first laser light source 51. The first laser light source 51 outputs a pulse laser beam having a wavelength of 808 nm, for example. The second laser light source 61 includes solid laser oscillators 61A and 61B. The solid-state laser oscillators 61A and 61B output a pulsed laser beam having a green wavelength. As the solid-state laser oscillators 61A and 61B, for example, an Nd: YAG laser, an Nd: YLF laser, an Nd: YVO ₄ laser, or the like that outputs a second harmonic is used.

  The pulse laser beam output from the first laser light source 51 and the pulse laser beam output from the second laser light source 61 are incident on the substrate 30 to be annealed via the propagation optical system 57. The pulse laser beam output from the first laser light source 51 and the pulse laser beam output from the second laser light source 61 are incident on the same region of the surface of the substrate 30. The substrate 30 is held on the stage 31.

  Next, the configuration and operation of the propagation optical system 57 will be described. The pulse laser beam output from the first laser light source 51 is incident on the substrate 30 via the attenuator 52, the beam expander 53, the beam homogenizer 54, the dichroic mirror 55, and the lens 56.

  The pulse laser beam output from one solid-state laser oscillator 61A enters the polarization beam splitter 65 via the attenuator 62A and the beam expander 63A. The pulse laser beam output from the other solid-state laser oscillator 61B is incident on the polarization beam splitter 65 via the attenuator 62B, the beam expander 63B, and the mirror 64. The pulse laser beams output from the two solid-state laser oscillators 61A and 61B are merged by the polarization beam splitter 65 and propagate along a common path.

  The pulsed laser beam merged into one path by the polarization beam splitter 65 is incident on the substrate 30 via the beam homogenizer 66, the dichroic mirror 67, the dichroic mirror 55, and the lens 56.

  The dichroic mirror 55 reflects light in the wavelength region of 800 nm and transmits light in other wavelength regions. The dichroic mirror 67 reflects light in the green wavelength range and transmits light in other wavelength ranges. The control device 35 controls the first laser light source 51, the second laser light source 61, and the stage 31.

  Thermal radiation light from the substrate 30 passes through the lens 56 and the dichroic mirrors 55 and 67 and enters the detection system 70. The detection system 70 includes the reference light source 20 (FIG. 1) and outputs reference light. The reference light output from the detection system 70 passes through the dichroic mirrors 67 and 55, is converged by the lens 56, and enters the substrate 30. The reflected light from the substrate 30 enters the detection system 70 following the same path as the reference light in the reverse direction.

  The pulse laser beam output from the first laser light source 51 mainly heats a deep region of the substrate 30. Thereby, the dopant in the deep region is activated. The 1st laser light source 51 or the 2nd laser light source 61 respond | corresponds to the laser light source 10 of the Example of FIGS. Since the dopant in the shallow region is activated at the same time by the activation of the dopant by the first laser light source 51, laser annealing by the second laser light source 61 described later may be performed as necessary.

  The pulse width of the pulse laser beam output from the two solid-state laser oscillators 61A and 61B of the second laser light source 61 is about 100 ns. That is, it is shorter than 1/100 of the pulse width of the pulse laser beam output from the first laser light source 51. Further, the peak intensity of the pulse laser beam output from the solid laser oscillators 61 </ b> A and 61 </ b> B is sufficiently larger than the peak intensity of the pulse laser beam output from the first laser light source 51. The short-pulse and high-intensity pulse laser beam output from the second laser light source 61 melts the surface layer portion of the substrate 30. The dopant is activated when the molten surface layer is recrystallized. The second laser light source 61 is used to activate a dopant in a relatively shallow region. If activation of a deep region is not necessary, the laser annealing process may be performed using only the second laser light source 61 without using the first laser light source 51.

  FIG. 8 shows a schematic diagram of the detection system 70. The configuration of the reference light source 20, the image sensor 21, the half-wave plate 22, the polarization beam splitter 23, the reference light detector 24, the quarter-wave plate 25, and the total reflection mirror 26 is the embodiment shown in FIG. The configuration is the same.

  The reference light output from the reference light source 20 and reflected by the total reflection mirror 26 passes through the dichroic mirror 72, is reflected by the dichroic mirror 71, is reflected by the total reflection mirror 14, and then passes through the propagation optical system 57. Then, the light enters the substrate 30 (FIG. 7). The dichroic mirror 71 transmits light having a wavelength range of 1 μm or more and reflects light having a wavelength range of 600 nm or more and less than 1 μm. The dichroic mirror 72 reflects light having a wavelength range of 860 nm or more and 940 nm or less and transmits light having a wavelength of 633 nm.

  The reflected light from the substrate 30 follows the incident path of the reference light in the opposite direction, enters the polarization beam splitter 23, and goes straight through the polarization beam splitter 23. Part of the reflected light that travels straight through the polarization beam splitter 23 is reflected by the beam splitter 28 and enters the image sensor 21. As the beam splitter 28, for example, a half mirror can be used. Part of the reflected light passes through the beam splitter 28, is converged by the lens 78, and enters the reflected light detector 79.

  When a pulsed laser beam is incident on the substrate 30 and heated, thermal radiation is emitted from the heated portion. Of the thermal radiation that has entered the detection system 70 from the propagation optical system 57, light in the wavelength region of less than 1 μm is reflected by the dichroic mirrors 71 and 72, converged by the lens 73, and then incident on the surface temperature detector 74. To do. For the surface temperature detector 74, for example, an avalanche photodiode can be used.

  The surface temperature detector 74 is required to have high-speed responsiveness in order to detect short-time melting due to a short pulse. By using an avalanche photodiode for the surface temperature detector 74, sufficient high-speed response can be ensured.

  Of the thermal radiation light incident on the detection system 70 from the propagation optical system 57, the light in the wavelength region longer than 1 μm passes through the dichroic mirror 71, is converged by the lens 16, and enters the infrared detector 17.

  Light having a wavelength region longer than 1 μm is transmitted through the silicon wafer. For this reason, thermal radiation light having a wavelength longer than 1 μm is also emitted to the outside from a deep region of the substrate 30 made of silicon. On the other hand, thermal radiation light having a wavelength shorter than 1 μm is easily absorbed by the substrate 30, so that thermal radiation light having a wavelength shorter than 1 μm generated in a deep region does not easily reach the outside of the substrate 30. For this reason, temperature information in a shallow region is mainly reflected in the intensity of thermal radiation light having a wavelength shorter than 1 μm. On the other hand, the temperature information of both the shallow region and the deep region is reflected in the intensity of the thermal radiation light having a wavelength longer than 1 μm.

  In the embodiment, thermal radiation light having a wavelength region shorter than 1 μm is detected by the surface temperature detector 74, and thermal radiation light having a wavelength region longer than 1 μm is detected by the infrared detector 17. Therefore, the temperature information of the shallow region of the substrate 30 can be obtained from the detection result of the surface temperature detector 74, and the temperature information of the deep region of the substrate 30 can be obtained from the detection result of the infrared detector 17.

  Based on the detection result of the reference light detector 24 and the detection result of the reflected light detector 79, the reflectance of the surface of the substrate 30 can be calculated. When the surface of the substrate 30 is melted, the reflectance changes. For this reason, it can be determined whether the surface of the board | substrate 30 was fuse | melted based on the reflectance.

  The reference light can be used for both an application for determining whether or not the surface of the substrate 30 has melted and an application for determining whether or not the local lift of the substrate 30 has occurred.

  Next, a laser annealing method using the laser annealing apparatus according to this embodiment will be described.

  FIG. 9 shows a locus 81 of the center of the beam spot 80 of the laser beam in the surface of the substrate 30. The beam spot 80 has a long shape that is long in one direction. An xy orthogonal coordinate system is defined in which the longitudinal direction of the beam spot 80 is defined as the y direction and the direction orthogonal thereto is defined as the x direction. By repeating the main scanning in the x direction and the sub scanning in the y direction of the pulse laser beam, the entire region of the substrate 30 is annealed.

  During the main scanning period, incident areas of shots adjacent to each other on the time axis partially overlap each other. The overlap rate is, for example, 50% or more and 99% or less. Similarly, the incident areas of the shots before and after the sub-scan in the y direction partially overlap each other. The overlap rate is, for example, 50%.

  The center point of the beam spot 80 when the local lift of the substrate 30 is detected is referred to as a lift detection point 90. The lift detection point 90 and its surrounding area are defined as an annealing exclusion area 91. In this embodiment, after the annealing exclusion region 91 is defined, control is performed so that the laser beam is not incident on the annealing exclusion region 91. For example, when the region where the pulse laser beam is incident is located inside the annealing exclusion region 91, the output of the pulse laser beam from the first laser light source 51 and the second laser light source 61 (FIG. 7) is temporarily changed. To stop. Alternatively, it is also possible to stop the incidence of the pulse laser beam by disposing a shutter in the path of the pulse laser beam and closing the shutter.

  The annealing exclusion region 91 can be a substantially square region having sides that are parallel to the x direction and the y direction, for example, with the floating detection point 90 as the center. The length of one side of the annealing exclusion region 91 is, for example, not less than 3 times and not more than 5 times the longitudinal dimension of the beam spot 80. In addition, the annealing exclusion area 91 may be circular with the lift detection point 90 as the center.

  In FIG. 9, the locus 81 of the center of the beam spot 80 in the area where the pulse laser beam has already entered and the area where the pulse laser beam is scheduled to enter is indicated by a solid line. A locus 82 at the center of the beam spot 80 when the pulse laser beam is assumed to be incident during the period in which the incidence of the pulse laser beam is interrupted is indicated by a broken line.

  FIG. 10 shows a flowchart of a laser annealing method using the laser annealing apparatus according to this embodiment. Hereinafter, differences from the laser annealing method shown in FIG. 6 will be described, and description of common configurations will be omitted.

  If it is determined in step S3 that the annealing of the entire region has not ended, in step S11, the incident position of the laser beam, for example, the center position of the beam spot 80 (FIG. 9) is located inside the annealing exclusion region 91 (FIG. 9). At this time, a control for temporarily interrupting the incidence of the pulse laser beam on the substrate 30 is executed. The movement of the stage 31 continues even during the period when the incidence of the pulse laser beam is interrupted. When the incident position of the laser beam deviates from the annealing exclusion region 91 (FIG. 9), the incidence of the pulsed laser beam on the substrate 30 is resumed. As long as the incident position of the pulse laser beam is located outside the annealing exclusion region 91, the incidence of the pulse laser beam on the substrate 30 continues as in the embodiment shown in FIG.

  In step S12, whether or not the substrate 30 is lifted is determined based on the detection results of the image sensor 21 and the surface temperature detector 74 (FIG. 8). In the embodiment shown in FIGS. 1 to 6, whether or not the substrate 30 is lifted is determined based only on the detection result of the image sensor 21.

  The floating of the substrate 30 is caused by excessive heating of the substrate 30 (hereinafter referred to as “floating due to heat storage”) and caused by a defect in the manufacturing process (hereinafter referred to as “lifting due to defective manufacturing”). Is included). Possible defects in the manufacturing process include, for example, a defect in the adhesive of the adhesive layer 33 (FIG. 2A), insufficient thickness of the substrate 30, and contamination by foreign matter between the substrate 30 and the base member 32 (FIG. 2A).

  From only the detection result of the image sensor 21, it is not possible to distinguish between floating due to heat storage and floating due to defective manufacturing. By using the detection result of the image sensor 21 and the detection result of the surface temperature detector 74 in combination, it is possible to distinguish between the lift due to heat storage and the lift due to defective manufacturing.

  When the amount of heat stored in the substrate 30 increases and exceeds a certain upper limit value, floating due to heat storage occurs. Therefore, it is considered that the amount of heat stored in the substrate 30 gradually increases before the lift due to heat storage occurs. Due to the increase in the heat storage amount, an increase in the surface temperature obtained from the detection result of the surface temperature detector 74 is observed for each shot of the pulse laser beam. On the other hand, when the lift due to manufacturing failure occurs, the occurrence of the lift and the amount of stored heat are irrelevant. For this reason, an increase in the surface temperature obtained from the detection result of the surface temperature detector 74 is not observed. Based on the time history of the surface temperature, it is possible to distinguish whether the lift is due to heat storage or a defective manufacturing process.

  After stopping the laser output, the stage movement, and the reference light output in step S7, it is determined in step S13 whether the cause of the lifting is a defective manufacturing process. If the lift is due to heat storage, the laser output condition is changed in step S8 as in the case of the laser annealing method shown in FIG. If the lift is due to a defect in the manufacturing process, an area including the lift detection point 90 (FIG. 9) is defined as an annealing exclusion area 91 in step S14. After the annealing exclusion region 91 is defined, the process returns to step S2 without changing the laser output condition.

  When the annealing exclusion area 91 is defined, the incidence of the pulse laser beam into the annealing exclusion area 91 is interrupted in step S11.

  Next, the excellent effect of the present embodiment will be described. In the method shown in FIG. 6, when lift is detected, the laser output condition is changed in step S8. However, it is not necessary to change the laser output conditions when the lift is not due to heat storage but due to a defective manufacturing process. For example, when the lift is due to a defect in the manufacturing process, if the pulse energy of the pulse laser beam is reduced, the possibility of an annealing failure occurring in the annealed region after the pulse energy reduction is increased.

  In the method shown in FIG. 10, when the lifting due to a defective manufacturing process occurs, the laser output condition is not changed, so that the possibility of an annealing failure does not increase.

  It is difficult for heat to escape to the stage 31 (FIG. 7) from a locally raised portion due to a defective manufacturing process. For this reason, the temperature rise by laser annealing is more likely to occur than in the region where there is no lifting. In this embodiment, since the laser beam is not incident on the annealing exclusion region 91 including the lift detection portion 90 where the local lift due to the defect is detected in the manufacturing process, the vicinity of the portion where the lift due to the manufacturing process failure occurs. The excessive temperature rise can be suppressed.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Laser light source 11 Uniform optical system 12 Dichroic mirror 13 Lens 14 Total reflection mirror 16 Lens 17 Infrared detector 20 Reference light source 21 Image sensor 22 1/2 wavelength plate 23 Polarizing beam splitter 24 Reference light detector 25 1/4 wavelength Plate 26 Total reflection mirror 27 Light receiving surface 28 Beam splitter 30 Substrate 30A Projection 31 Stage 32 Base member 33 Adhesive layer 34 Composite substrate 35 Control device 36 Storage device 37 Input device 38 Output device 40 Incident area 41 of reflected light Reference area 43 Reflection Permissible range 44 of the incident region of light 51 Permissible range of the incident region of reflected light 51 First laser light source 52 Attenuator 53 Beam expander 54 Beam homogenizer 55 Dichroic mirror 56 Lens 57 Propagation optical system 61 Second laser Light source 61A, 61B Solid Laser oscillator 62A, 62B Attenuator 63A, 63B Beam expander 64 Mirror 65 Polarizing beam splitter 66 Beam homogenizer 67 Dichroic mirror 70 Detection system 71, 72 Dichroic mirror 73 Lens 74 Surface temperature detector 78 Lens 79 Reflected light detector 80 Beam spot 81, 82 Trajectory 90 Lift detection location 91 Annealing exclusion region L0 Pulse laser beam L1 Reference light L2 Reflected light

Claims (10)

A laser light source for outputting a laser beam;
A stage for holding a substrate to be annealed at a position where the laser beam output from the laser light source is incident;
A reference light source for making reference light incident on the substrate held on the stage;
An image sensor that receives reflected light of the reference light incident on the surface of the substrate;
A laser annealing apparatus comprising: a control device that determines whether or not the substrate is locally lifted from the stage based on a detection result of the reflected light detected by the image sensor.   The laser annealing apparatus according to claim 1, wherein the control device determines whether or not the substrate is locally lifted from the stage based on an incident position of the reflected light in a light receiving surface of the image sensor.   2. The laser annealing according to claim 1, wherein the control device determines whether or not the substrate is locally lifted from the stage based on a size of an incident region of the reflected light in a light receiving surface of the image sensor. apparatus.   The laser annealing apparatus according to claim 1, wherein the controller determines whether or not the substrate is locally lifted from the stage based on the intensity of the reflected light incident on a light receiving surface of the image sensor. The control device includes:
While controlling the stage and moving the substrate in the in-plane direction, the laser beam output from the laser light source is incident on the substrate,
The laser annealing according to any one of claims 1 to 4, wherein an incident position of the reference light in a surface of the substrate when it is determined that there is a local lift of the substrate is stored as lift position information. apparatus. The control device includes:
While controlling the stage and moving the substrate in the in-plane direction, the laser beam output from the laser light source is incident on the substrate,
When it is determined that there is local lifting of the substrate, the output of the laser beam from the laser light source is temporarily stopped,
The laser annealing apparatus according to any one of claims 1 to 5, wherein, after the output of the laser beam is stopped, the output condition of the laser beam is changed and the output of the laser beam is restarted. The control device includes:
While controlling the stage and moving the substrate in the in-plane direction, the laser beam output from the laser light source is incident on the substrate,
When it is determined that there is local lifting of the substrate, the output of the laser beam from the laser light source is temporarily stopped,
After stopping the output of the laser beam, performing a control not to make the laser beam incident on an annealing exclusion region including a portion determined to have a local lift of the substrate,
6. The laser beam according to claim 1, wherein the laser beam is incident on a region other than the annealing exclusion region under the same condition as that before the time point when the local lifting is determined to be present. Laser annealing equipment. Adsorbing a composite substrate including a base member and a substrate to be annealed attached to the base member with an adhesive to the stage in a posture where the base member faces the stage;
A step of causing a laser beam to be incident on the composite substrate adsorbed on the stage and moving an incident position in a plane of the composite substrate;
A step of causing a reference beam to be incident on an incident position of the laser beam on the composite substrate;
Receiving reflected light of the reference light from the composite substrate with an image sensor;
Determining whether or not the substrate is locally lifted from the base member based on a detection result of the reflected light by the image sensor.   The method according to claim 8, wherein when it is determined that there is local lifting of the substrate, the incidence of the laser beam is temporarily stopped, the output condition of the laser beam is changed, and the incidence of the laser beam is resumed. The laser annealing method as described. If it is determined that there is a local lift of the substrate, temporarily stop the laser beam incidence,
After stopping the output of the laser beam, the laser beam is not incident on an annealing exclusion region including a portion determined to have local lift of the substrate,
9. The laser annealing method according to claim 8, wherein the laser beam is incident on a region other than the annealing excluded region under the same condition as the condition before the time point when it is determined that the local lifting is present.

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