Annealing evaluation device, annealing device, annealing evaluation method, and annealing method

Abstract

To provide an annealing evaluation device capable of evaluating annealing not in contact with a surface of an object to be annealed such as a semiconductor wafer.SOLUTION: Intensity of diffracted light diffracted in directions of the same angle of diffraction is measured by an optical detector at a plurality of evaluation object parts on a surface of an object of annealing having been annealed while a beam spot is moved under the condition that a movement distance of the beam spot is 10 μm or less in one cycle of the pulse laser beam. At least one of the object of annealing and the optical detector is moved by a moving mechanism so that diffracted light from the plurality of evaluation object parts on the surface of the object of annealing can be detected. A controller controls the moving mechanism to acquire measured values of intensity of diffracted light measured by the optical detector at the plurality of evaluation object parts, and then outputs information for determining whether the annealing is satisfactory to an output device.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an annealing evaluation device, an annealing device, an annealing evaluation method, and an annealing method. [Background technology]

[0002] Conventionally, the sheet resistance is measured as an example of a method for understanding the in-plane distribution of the activation state of a semiconductor wafer that has been implanted with dopants and then activated by annealing. The activation state of the dopants can be evaluated from the in-plane distribution of the sheet resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-81348 Summary of the Invention [Problem to be solved by the invention]

[0004] The four-point probe method is generally used to measure sheet resistance. Sheet resistance measurement using the four-point probe method is performed after annealing in a device separate from the activation annealing device. This makes sheet resistance measurement an offline process, which is time-consuming. In addition, the semiconductor wafer can be damaged because the probe must be brought into contact with the wafer.

[0005] The object of the present invention is to Ha's Without contact with the surface activation The present invention provides an annealing evaluation device, an annealing device, an annealing evaluation method, and an annealing method that can evaluate annealing. [Means for solving the problem]

[0006] According to one aspect of the present invention, a photodetector that measures the intensity of diffracted light diffracted in the same direction at a plurality of evaluation target locations on the surface of the semiconductor wafer that has been subjected to dopant activation annealing by moving the beam spot under the condition that the moving distance of the beam spot in one period of the pulsed laser beam is 10 μm or less; a moving mechanism that moves at least one of the semiconductor wafer and the photodetector so that diffracted light from each of a plurality of evaluation target locations on the surface of the semiconductor wafer can be detected by the photodetector; an output device; a control device that controls the moving mechanism to acquire measured values of the intensity of diffracted light measured by the photodetector for the plurality of evaluation target locations, and outputs information that determines whether activation annealing has been performed successfully to the output device; and Equipped with 、 The position and orientation of the photodetector are set so that, when an evaluation laser beam is incident on the surface of the semiconductor wafer, diffracted light diffracted in a direction of a diffraction angle determined according to the movement distance of the beam spot in one period of the pulse laser beam, the wavelength of the evaluation light, and the incident angle is detected. An annealing evaluation device is provided.

[0007] According to another aspect of the present invention, the annealing evaluation device; The aforementioned semiconductor wafer to activation a laser light source that emits the pulsed laser beam for annealing; an attenuator that attenuates the pulsed laser beam output from the laser light source; Including, The control device controls the attenuator to semiconductor wafer The power of the pulse laser beam on the surface is made lower than the power during processing. semiconductor wafer and obtaining a measurement of the intensity of the diffracted light from the photodetector.

[0008] According to yet another aspect of the present invention, a semiconductor wafer that has undergone dopant activation annealing by moving a beam spot under conditions that the moving distance of the beam spot in one period of the pulsed laser beam is 10 μm or less; A laser beam for evaluation is incident on the surface of the semiconductor wafer, and the light is diffracted in the direction of a diffraction angle determined according to the movement distance of the beam spot in one period of the pulse laser beam, the wavelength of the light for evaluation, and the angle of incidence. observing diffracted light from the surface of the semiconductor wafer; An annealing evaluation method is provided for determining whether activation annealing is good or bad based on the results of observing diffracted light.

[0009] According to yet another aspect of the present invention, A pulsed laser beam is irradiated onto the semiconductor wafer to which the dopant has been added, and the surface layer of the semiconductor wafer is temporarily melted and activated while the beam spot is moved under the condition that the moving distance of the beam spot in one period of the pulsed laser beam is 10 μm or less; On the surface of the semiconductor wafer after activation annealing The laser beam for evaluation is incident, and the light is diffracted in the direction of a diffraction angle determined according to the movement distance of the beam spot in one period of the pulse laser beam, the wavelength of the light for evaluation, and the angle of incidence. Observe the diffracted light, An annealing method is provided for determining whether activation annealing is good or bad based on the results of observing diffracted light. [Effects of the Invention]

[0010] Since diffracted light is used to evaluate the object to be annealed, the evaluation can be performed without bringing a probe or the like into contact with the object to be annealed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic perspective view of an annealing apparatus equipped with an annealing evaluation apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram of an annealing apparatus equipped with an annealing evaluation apparatus according to the embodiment. [Figure 3] FIG. 3 is a schematic diagram showing the positional relationship between the photodetector and the object to be annealed. [Figure 4] FIG. 4A is a schematic diagram showing the trajectory of movement of the beam spot, and FIG. 4B is a schematic diagram showing the shape of the surface of the object to be annealed after annealing and the state of diffraction. [Figure 5] FIG. 5 is a flowchart showing the procedure of the annealing method and the annealing evaluation method according to the embodiment. [Figure 6] FIG. 6 is a diagram showing an example of an image output to an output device. [Figure 7]FIG. 7 is a partial schematic diagram of an annealing evaluation apparatus according to another embodiment. [Figure 8] FIG. 8 is a schematic diagram showing the positional relationship between evaluation light, diffracted light, and a photodetector used in an annealing evaluation method according to still another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] An annealing evaluation device according to one embodiment will be described with reference to FIGS. 1 is a schematic perspective view of an annealing apparatus equipped with an annealing evaluation apparatus according to an embodiment. A laser light source 10 outputs a pulsed laser beam. The pulsed laser beam output from the laser light source 10 passes through a beam expander 11, an attenuator 12, a beam shaping optical element 13, folding mirrors 14 and 15, a beam scanner 16, and an fθ lens 17 and is incident on an object to be annealed 50. The object to be annealed 50 is, for example, a semiconductor wafer into which dopant ions have been implanted.

[0013] The annealing object 50 is held by a chuck mechanism 18 supported by a movement mechanism 19. The movement mechanism 19 moves the chuck mechanism 18 in two directions in a horizontal plane. As the movement mechanism 19, for example, an XY stage is used.

[0014] The beam expander 11 adjusts the beam size (beam cross-sectional diameter) at the position where the laser beam is incident on the beam shaping optical element 13. The attenuator 12 attenuates the power of the pulsed laser beam. The attenuation rate of the attenuator 12 is variable. The beam shaping optical element 13 shapes the shape and intensity distribution of the beam spot on the beam-irradiated surface of the object to be annealed 50. For example, a diffractive optical element is used as the beam shaping optical element 13. The beam scanner 16 includes a galvanometer mirror 16A and a motor 16B. The motor 16B rotates the galvanometer mirror 16A within a certain range in the tilt direction, thereby scanning the pulsed laser beam in a one-dimensional direction. The fθ lens 17 focuses the pulsed laser beam scanned by the beam scanner 16 on the laser-irradiated surface of the object to be annealed 50.

[0015] Diffracted light from the object to be annealed 50 is incident on the photodetector 20. The photodetector 20 measures the intensity of the diffracted light. The measured value of the intensity of the diffracted light is input to the control device 40. The control device 40 controls the laser light source 10, the attenuator 12, the beam scanner 16, and the movement mechanism 19, and outputs the evaluation result to the output device 41.

[0016] 2 is a schematic diagram of an annealing apparatus equipped with the annealing evaluation apparatus according to this embodiment. Explanation of the contents overlapping with the explanation of FIG. 1 will be omitted.

[0017] A fiber laser oscillator is used as the laser light source 10. An input optical fiber 32 is connected to one end of a gain fiber 31 doped with a laser active medium, and an output optical fiber 34 is connected to the other end. A high-reflectivity fiber Bragg grating 33 is formed in the input optical fiber 32, and a low-reflectivity fiber Bragg grating 35 is formed in the output optical fiber 34. The high-reflectivity fiber Bragg grating 33 and the low-reflectivity fiber Bragg grating 35 form an optical resonator.

[0018] Pumping light output from the laser diode 30 is introduced into the gain fiber 31 through the input optical fiber 32. The laser active medium doped in the gain fiber 31 is excited by the pumping light. When the laser active medium transitions to a low energy state, stimulated emission occurs, generating laser light. The laser light generated in the gain fiber 31 passes through the output optical fiber 34 and enters the wavelength conversion element 36. The laser beam wavelength-converted by the wavelength conversion element 36 passes through the beam expander 11, the attenuator 12, the beam shaping optical element 13, the folding mirrors 14 and 15, the beam scanner 16, and the fθ lens 17 and is then incident on the object to be annealed 50. The gain fiber 31 outputs laser light, for example, in the infrared region, and the wavelength conversion element 36 converts the infrared laser light into laser light in the green wavelength region.

[0019] The driver 37 drives the laser diode 30 based on a command from the control device 40. The command received from the control device 40 includes information specifying the repetition frequency of the laser pulses output from the laser diode 30. The driver 37 causes the laser diode 30 to output an excitation laser beam at the repetition frequency of the laser pulses commanded by the control device 40. As a result, a pulsed laser beam is output from the laser light source 10 at the commanded repetition frequency.

[0020] A moving mechanism 19 and a chucking mechanism 18 are disposed in a chamber 60. A laser transmitting window 61 is attached to the wall of the chamber 60 above the object to be annealed 50 held by the chucking mechanism 18. A pulsed laser beam transmitted through the fθ lens 17 passes through the laser transmitting window 61 and is incident on the surface of the object to be annealed 50 (hereinafter sometimes referred to as the laser irradiation surface). The annealing apparatus according to this embodiment performs activation annealing of dopants doped into the object to be annealed 50, which is, for example, a semiconductor wafer. The object to be annealed 50 is, for example, a silicon wafer.

[0021] The control device 40 includes a console operated by a user. The user operates the console to input information specifying the pulse repetition frequency of the pulse laser beam. The control device 40 then provides the input information specifying the pulse repetition frequency to the driver 37.

[0022] The control device 40 further controls the beam scanner 16 and the movement mechanism 19 to move the beam spot on the laser irradiation surface of the object to be annealed 50. An xyz Cartesian coordinate system is defined in which the direction in which the beam spot moves as a result of scanning the pulsed laser beam with the beam scanner 16 is the x direction, and the direction perpendicular to the x direction in the laser irradiation surface is the y direction. The movement of the beam spot in the x direction as a result of scanning the pulsed laser beam with the beam scanner 16 is referred to as "sweeping." The control device 40 anneals the object to be annealed 50 by repeating a sweeping operation in which the beam scanner 16 sweeps the beam spot in the x direction, and a stepping operation in which the movement mechanism 19 moves the object to be annealed 50 in the y direction.

[0023] The maximum length over which the beam spot can be swept in the x direction depends on the deflection angle of the pulsed laser beam by the beam scanner 16 and the performance of the fθ lens 17. When the maximum sweep length is shorter than the dimensions of the object to be annealed 50, it is possible to anneal almost the entire area of the object to be annealed 50 by combining a procedure of repeating the sweeping operation and stepping operation multiple times with a procedure of moving the object to be annealed 50 in the x direction.

[0024] 4A and 4B, this annealing forms periodic unevenness on the surface of the annealing object 50. This unevenness functions as a diffraction grating.

[0025] When evaluating the annealed object 50, the control device 40 controls the attenuator 12 to set a higher attenuation rate than during processing. The pulse laser beam incident on the object 50 with a higher attenuation rate than during processing is referred to as the evaluation pulse laser beam. The peak power of the evaluation pulse laser beam is lower than the peak power of the annealing pulse laser beam.

[0026] When the evaluation pulsed laser beam is incident, the control device 40 controls the moving mechanism 19 to raise and lower the chuck mechanism 18. As a result, the surface of the to-be-annealed object 50 is moved out of the focal position of the beam shaping optical element 13, and the beam spot on the beam-irradiated surface of the to-be-annealed object 50 becomes larger than the beam spot during processing. Even when the evaluation pulsed laser beam is incident on the to-be-annealed object 50, the surface layer of the to-be-annealed object 50 does not melt, and solid-phase diffusion of the dopant does not occur.

[0027] The evaluation pulse laser beam incident on the annealing object 50 is diffracted by a diffraction grating made up of uneven portions formed on the surface of the annealing object 50. Any of the first-order or higher-order diffracted light is detected by the photodetector 20.

[0028] FIG. 3 is a schematic diagram showing the positional relationship between the photodetector 20 and the object to be annealed 50. A pulsed laser beam Le for evaluation is incident on the beam irradiation surface of the object to be annealed 50. The photodetector 20 includes a pinhole light shielding plate 20A and a photodetector 20B. Of the diffracted light from the surface of the object to be annealed 50, diffracted light Ld1 that passes through the pinhole in the pinhole light shielding plate 20A is incident on the photodetector 20B. In other words, diffracted light diffracted from a specific diffracted light detection point Pd in a direction at a specific diffraction angle θd is detected by the photodetector 20. Here, the diffraction angle θd refers to the angle between the normal to the surface of the object to be annealed 50 and the traveling direction of the diffracted light.

[0029] By moving the chuck mechanism 18 to move the annealing object 50 in the x or y direction and moving the location to be evaluated (hereinafter referred to as the evaluation location) to the diffracted light detection location Pd, it is possible to detect diffracted light from multiple evaluation locations on the surface of the annealing object 50. Even when the annealing object 50 is moved in the x or y direction, the diffraction angle θd of the diffracted light detected by the photodetector 20 remains constant. In other words, the intensity of diffracted light Ld1 diffracted in the same direction with the diffraction angle θd from multiple evaluation locations on the surface of the annealing object 50 is measured.

[0030] Next, the sweeping and stepping operations during annealing will be described with reference to FIGS. 4A and 4B.

[0031] FIG. 4A is a schematic diagram showing the trajectory of movement of the beam spot 39. The movement direction of the beam spot 39 relative to the surface of the annealing object 50 is indicated by a white arrow. The beam spot 39 is, for example, a rounded rectangle whose length is in the y direction. The dimension of the beam spot 39 in the x direction is denoted as Lx, and the dimension in the y direction is denoted as Ly. As an example, Lx is 100 μm, and Ly is 300 μm. The beam spot 39 may also be a rounded square.

[0032] During the sweep operation, the movement distance of the beam spot 39 in the x direction in one period of the pulsed laser beam is denoted as Wx. The movement distance of the beam spot 39 in the y direction during the step operation is denoted as Wy. The movement distance Wx is determined by the pulse repetition frequency of the pulsed laser beam and the movement speed of the beam spot 39 in the x direction. As an example, the pulse repetition frequency is 15 kHz or higher. The movement distance Wy during the step operation is, for example, 1 / 2 of the dimension Ly of the beam spot 39 in the y direction. This results in an overlap rate of 50% for the beam spot 39 in the y direction.

[0033] FIG. 4B is a schematic diagram showing the surface shape and diffraction pattern of the annealing object 50 after annealing. The pulse energy density of the pulsed laser beam used for annealing is set to a value that can temporarily melt the surface layer of the annealing object 50. Therefore, the surface layer of the annealing object 50 melts and solidifies upon irradiation with the laser pulse. At this time, the ion-implanted dopants are activated. Furthermore, as the surface layer of the annealing object 50 melts and solidifies, an uneven portion 51 is generated along the edge of the temporarily melted region. Note that while FIG. 4B shows the uneven portion 51 as a convex portion, depending on the annealing conditions, a concave portion or a combination of a convex portion and a concave portion may also be generated.

[0034] By sweeping the beam spot 39 (FIG. 4A), a plurality of concave-convex portions 51 are distributed at equal intervals in the x direction. The pitch Px of the concave-convex portions 51 in the x direction is equal to the movement distance Wx (FIG. 4A) of the beam spot 39 in the x direction. The height h of the concave-convex portions 51 depends on the degree (depth) of melting of the surface layer of the object to be annealed 50 when the pulsed laser beam for annealing is incident thereon.

[0035] Next, the diffracted light when a pulsed laser beam Le for evaluation is incident on the surface of the annealing object 50 after annealing will be described.

[0036] A plurality of concave-convex portions 51 are distributed within the beam spot 24 of the evaluation pulsed laser beam Le. The plurality of concave-convex portions 51 function as a diffraction grating, thereby diffracting the evaluation pulsed laser beam Le. In order for the plurality of concave-convex portions 51 to function as a diffraction grating, it is preferable that the pitch Px of the concave-convex portions 51 be 10 μm or less. For example, if the pulse repetition frequency of the annealing pulsed laser beam is 1 MHz and the moving speed of the annealing object 50 in the x direction is 5 m / s, the pitch Px is 5 μm. When the evaluation pulsed laser beam Le is perpendicularly incident on the surface of the annealing object 50, higher-order diffracted light, such as first-order diffracted light Ld1 and second-order diffracted light Ld2, appears in directions inclined toward the x direction.

[0037] The diffraction angle is determined by the wavelength and incident angle of the evaluation pulse laser beam Le and the pitch Px of the concave-convex portions 51. The intensity of the diffracted light varies depending on the height h of the concave-convex portions 51. In order to ensure sufficient measurement accuracy of the intensity of the diffracted light, it is preferable to keep the diffraction angle θd and the distance from the diffracted light detection point Pd to the photodetector 20 constant. When monochromatic light such as a laser beam is used as the evaluation light, the diffraction angle θd is determined by the wavelength of the evaluation light, the incident angle of the evaluation light, and the pitch Px of the concave-convex portions 51.

[0038] Next, an annealing method and an annealing evaluation method according to an embodiment will be described with reference to FIG. Fig. 5 is a flowchart showing the steps of the annealing method and annealing evaluation method according to this embodiment. Each step shown in Fig. 5 is performed by the control device 40 (Figs. 1 and 2) controlling the laser light source 10, attenuator 12, beam scanner 16, and movement mechanism 19 of the annealing device, and acquiring a measurement value of the intensity of diffracted light from the photodetector 20.

[0039] First, the control device 40 controls the laser light source 10, attenuator 12, beam scanner 16, and movement mechanism 19 to repeatedly perform sweeping and stepping operations while irradiating the pulsed laser beam for annealing onto the object to be annealed 50 (step S1). This causes annealing of the object to be annealed 50. During this process, unevenness 51 (FIG. 4B) is generated on the surface of the object to be annealed 50.

[0040] When annealing of almost the entire surface of the annealing object 50 is completed, the control device 40 controls the attenuator 12 (FIGS. 1 and 2) to make the attenuation rate higher than that during processing (step S2). Furthermore, the control device 40 controls the movement mechanism 19 to raise and lower the annealing object 50, thereby making the beam spot on the surface of the annealing object 50 larger than that during processing (step S3).

[0041] Thereafter, the control device 40 controls the moving mechanism 19 to move the annealing object 50 in the x and y directions, thereby moving the evaluation target area on the surface of the annealing object 50 to the diffracted light detection location Pd (Figure 3) of the photodetector 20 (step S4).

[0042] The beam scanner 16 is adjusted, for example, so that the evaluation pulse laser beam is incident on the annealing object 50 along the optical axis of the fθ lens 17 (FIG. 2). The position and attitude of the photodetector 20 are adjusted so that the photodetector 20 detects first-order diffracted light Ld1 from the point where the surface of the annealing object 50 intersects with the optical axis of the fθ lens 17. That is, the point where the surface of the annealing object 50 intersects with the optical axis of the fθ lens 17 is set as the diffracted light detection point Pd (FIG. 3) of the photodetector 20. Note that the position where the evaluation pulse laser beam is incident when the galvanometer mirror 16A (FIG. 1) of the beam scanner 16 is stationary in a specific attitude may be set as the diffracted light detection point Pd.

[0043] The control device 40 controls the laser light source 10 to irradiate the evaluation pulse laser beam Le (FIG. 4B) onto the object to be annealed 50, and obtains a measurement value of the intensity of the diffracted light from the photodetector 20 (step S5).

[0044] The control device 40 repeats steps S4 and S5 until measurements are completed for all evaluation locations (step S6). The positions of the multiple evaluation locations are determined in advance, and position information for the evaluation locations is stored in the control device 40. For example, in step S4, the control device 40 controls the movement mechanism 19 to move the annealing object 50 in the x direction or y direction, thereby moving the evaluation location to be next evaluated to the diffracted light detection location Pd (FIG. 3) of the photodetector 20.

[0045] When the measurement for all evaluation locations is completed, the control device 40 outputs information for determining whether the annealing is successful to the output device 41 (FIGS. 1 and 2) (step S7). The information for determining whether the annealing is successful includes, for example, information indicating the intensity of diffracted light at each of the multiple evaluation locations.

[0046] FIG. 6 is a diagram showing an example of an image output to the output device 41 (FIGS. 1 and 2). The surface of the annealing object 50 is divided into square regions 52 for each evaluation location, and the multiple regions 52 are color-coded according to the measured values of the diffracted light intensity. For example, the diffracted light intensity is divided into five levels, and the multiple regions 52 are color-coded into five colors. In FIG. 6, differences in color are represented by differences in the density of hatching.

[0047] FIG. 6 shows an example in which a plurality of evaluation target locations are distributed over almost the entire surface of the object to be annealed 50, but the plurality of evaluation target locations may also be distributed sparsely.

[0048] Next, the excellent effects of the above embodiment will be described. If the pulse energy density of the pulsed laser beam used for annealing is too low, melting will be insufficient, and the height h of the unevenness 51 (FIG. 4B) generated on the surface of the annealing object 50 will be small, or the unevenness 51 will not be formed at all. As a result, the intensity of the diffracted light will decrease or become zero. Furthermore, if excessive melting occurs, the height h of the unevenness 51 will increase, and the intensity of the diffracted light will increase. If the annealing is performed well, the intensity of the diffracted light will fall within a certain allowable range. The quality of the annealing can be determined from the distribution of the diffracted light intensity shown in FIG. 6.

[0049] Furthermore, the uniformity of the annealing process within the surface of the object to be annealed 50 can be evaluated from the distribution of the intensity of the diffracted light.

[0050] In addition, in the above embodiment, the sheet resistance is not measured using a four-point probe method or the like, so the quality of the annealing can be determined without contacting a probe or the like with the surface of the annealing object 50. Furthermore, the pulsed laser beam for evaluation is generated by attenuating the pulsed laser beam output from the laser light source 10 for the annealing pulsed laser beam with an attenuator 12 (FIGS. 1 and 2). Therefore, there is no need to provide a separate light source for evaluation. Furthermore, after annealing, the annealing can be evaluated without removing the annealing object 50 from the annealing apparatus.

[0051] Next, a modification of the above embodiment will be described. In the above embodiment, the measured value of the diffracted light intensity is output in step S7 (FIG. 5), but the control device 40 may determine whether the annealing is successful or not based on the measured value of the diffracted light intensity and output the determination result. For example, the control device 40 may determine whether the diffracted light intensity measured by the photodetector 20 is within an acceptable range and output the determination result to the output device 41. Also, in the above embodiment, the photodetector 20 (FIG. 3) detects the first-order diffracted light Ld1, but it may also be configured to detect second-order or higher-order diffracted light.

[0052] In the above embodiment, a pinhole light shielding plate 20A (FIG. 3) is used to allow diffracted light of a specific diffraction angle to reach the light detection unit 20B. However, a light shielding plate with slits parallel to the y direction may also be used. In this case, a line sensor elongated in a direction parallel to the y direction may be used as the light detection unit 20B. This configuration allows the diffracted light detection point Pd to be elongated in the y direction.

[0053] In the above embodiment, the photodetector 20 is kept stationary while the object to be annealed 50 is moved during evaluation, but conversely, the object to be annealed 50 may be kept stationary while the photodetector 20 is moved.

[0054] Next, an annealing evaluation device according to another embodiment will be described with reference to Fig. 7. Below, a description of the configuration common to the embodiment shown in Figs.

[0055] Fig. 7 is a partial schematic diagram of an annealing evaluation apparatus according to another embodiment. In the embodiment shown in Figs. 1 to 6, the pulse laser beam output from the laser light source 10 (Figs. 1 and 2) that outputs the pulse laser beam for annealing is attenuated and used as the pulse laser beam for evaluation. In contrast, in the embodiment shown in Fig. 7, a light source 25 that outputs light for evaluation is arranged separately from the laser light source 10. The light source 25 for evaluation may be arranged inside or outside the chamber 60 (Fig. 2).

[0056] The evaluation light source 25 emits evaluation light Le into an area including the diffracted light detection point Pd. In the embodiment shown in FIG. 3, the evaluation pulse laser beam Le is perpendicularly incident on the surface of the annealing object 50, but in the embodiment shown in FIG. 7, the incidence is not limited to perpendicular incidence and may be oblique incidence. Furthermore, the evaluation light Le does not need to be a laser beam. The position and orientation of the photodetector 20 are adjusted so that the first-order diffracted light Ld1 from the diffracted light detection point Pd is detected by the photodetector 20. Note that the second-order diffracted light Ld2 may be detected, or higher-order diffracted light such as third order or higher may be detected. The specular reflection light Ld0 does not enter the photodetector 20.

[0057] The evaluation light source 25 outputs monochromatic light or white light. When the evaluation light Le is monochromatic light, first-order diffracted light Ld1 appears in the direction of a specific diffraction angle according to the pitch Px of the uneven portion 51 (FIG. 4B). When the evaluation light is white light, first-order diffracted light Ld1 appears within a certain angular range of diffraction angles. By adjusting the position and attitude of the photodetector 20, it is possible to detect only diffracted light of a specific wavelength. Therefore, information regarding the height h of the uneven portion 51 (FIG. 4B) is fully reflected in the intensity of the diffracted light.

[0058] Next, the excellent effects of the embodiment shown in FIG. 7 will be described. 7, the evaluation light source 25 is arranged separately from the annealing laser light source 10, which increases the degree of freedom in selecting the wavelength and incident angle of the evaluation light Le. This makes it possible to select a wavelength and incident angle suitable for evaluation.

[0059] Next, a modification of the embodiment shown in FIG. 7 will be described. 7, an evaluation light source 25 is provided, but it is also possible to use light from the room lighting of the building in which the laser annealing apparatus is installed as the evaluation light. For example, if the light from the room lighting has a certain degree of parallelism on the surface of the annealing object 50, the light from the room lighting can be used as the evaluation light.

[0060] Next, an annealing evaluation method according to yet another embodiment will be described with reference to Fig. 8. Below, a description of the configuration common to the embodiment shown in Figs.

[0061] 8 is a schematic diagram showing the positional relationship between the evaluation light Le, diffracted light Ld, and photodetector 20 used in the annealing evaluation method according to this embodiment. In this embodiment, an imaging device, such as a camera, that captures an image of the surface of the annealing object 50 is used as the photodetector 20. The evaluation light Le is incident on the entire surface of the annealing object 50, and the diffracted light Ld is incident on the photodetector 20. The photodetector 20 is positioned so that specularly reflected light of the evaluation light Le does not enter the photodetector 20.

[0062] The photodetector 20 obtains an image of the surface of the annealing object 50. This image reflects the intensity distribution of the diffracted light within the surface of the annealing object 50. For example, the image becomes brighter in areas where the height h of the uneven portion 51 (FIG. 4B) is relatively high.

[0063] Next, the excellent effects of the embodiment shown in FIG. 8 will be described. In the embodiment shown in FIG. 8, the in-plane uniformity of annealing can be evaluated based on the observation results of diffracted light from the surface of the object 50 to be annealed.

[0064] The above-described embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. Similar effects resulting from similar configurations of multiple embodiments will not be mentioned sequentially for each embodiment. Furthermore, the present invention is not limited to the above-described embodiments. For example, it will be obvious to those skilled in the art that various modifications, improvements, combinations, etc. are possible. [Explanation of symbols]

[0065] 10 Laser light source 11 Beam Expander 12 Attenuator 13 Beam shaping optical elements 14, 15 Folding mirror 16 Beam Scanner 16A Galvanometer Mirror 16B motor 17 fθ lens 18 Chuck mechanism 19 Moving mechanism 20 Photodetector 20A pinhole 20B Light detection unit 24 Beam spot of pulsed laser beam for evaluation 25 Evaluation light source 30 Laser Diode 31 Gain fiber 32 Input optical fiber 33 Fiber Bragg Grating 34 Output optical fiber 35 Fiber Bragg Grating 36 Wavelength conversion element 37 Drivers 39 Beam spot of pulsed laser beam for annealing 40 Control device 41 Output Device 50 Annealing object 51 Uneven part 52 Areas divided into areas to be evaluated 60 Chambers 61 Laser transmission window

Claims

1. a photodetector for measuring the intensity of diffracted light diffracted in the same direction at a plurality of evaluation target locations on the surface of the semiconductor wafer that has been subjected to dopant activation annealing by moving the beam spot under the condition that the moving distance of the beam spot in one period of the pulsed laser beam is 10 μm or less; a moving mechanism that moves at least one of the semiconductor wafer and the photodetector so that diffracted light from each of a plurality of evaluation target locations on the surface of the semiconductor wafer can be detected by the photodetector; an output device; a control device that controls the moving mechanism to acquire measured values of the intensity of diffracted light measured by the photodetector for the plurality of evaluation target locations, and outputs information that determines whether activation annealing has been performed successfully to the output device; and Equipped with The photodetector is positioned and oriented so that, when an evaluation laser beam is incident on the surface of the semiconductor wafer, diffracted light diffracted in a direction of a diffraction angle determined according to the movement distance of the beam spot in one period of the pulsed laser beam, the wavelength of the evaluation light, and the incident angle.

2. 2. The annealing evaluation device according to claim 1, wherein the control device determines whether the intensity of the diffracted light measured by the photodetector falls within an allowable range, and outputs the determination result to the output device.

3. An annealing evaluation device according to claim 1 or 2; a laser light source that irradiates the semiconductor wafer with the pulsed laser beam for activation annealing; an attenuator that attenuates the pulsed laser beam output from the laser light source; Including, The control device controls the attenuator to lower the power of the pulsed laser beam on the surface of the semiconductor wafer below the power during processing, and then the pulsed laser beam is incident on the semiconductor wafer, and the measurement value of the intensity of the diffracted light is obtained from the photodetector.

4. a semiconductor wafer is prepared, which has undergone dopant activation annealing by moving a beam spot under the condition that the moving distance of the beam spot in one period of the pulsed laser beam is 10 μm or less; an evaluation laser beam is incident on the surface of the semiconductor wafer, and diffracted light from the surface of the semiconductor wafer in a direction of a diffraction angle determined according to a movement distance of a beam spot of the pulsed laser beam in one period, a wavelength of the evaluation light, and an incident angle; An annealing evaluation method that determines the quality of activation annealing based on the results of observing diffracted light.

5. a pulsed laser beam is irradiated onto the semiconductor wafer to which the dopant has been added, and the surface layer of the semiconductor wafer is temporarily melted while the beam spot is moved under the condition that the moving distance of the beam spot in one period of the pulsed laser beam is 10 μm or less, thereby performing activation annealing; an evaluation laser beam is incident on the surface of the semiconductor wafer after activation annealing, and diffracted light diffracted in a direction of a diffraction angle determined according to the movement distance of the beam spot in one period of the pulsed laser beam, the wavelength of the evaluation light, and the incident angle; An annealing method that judges the quality of activation annealing based on the results of observing diffracted light.

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