Laser annealing apparatus, laser annealing method, and method for manufacturing semiconductor device

Abstract

The present invention relates to a laser annealing apparatus, according to one embodiment, including: a laser light source; an annealing optical system; a linear irradiation region in a Y direction; a moving mechanism configured to change a relative position of the irradiation region with respect to a substrate along an X direction; an illumination light source configured to generate an illumination light for illuminating the substrate in a third direction; and a detector configured to detect a detection light reflected in a fourth direction on the substrate illuminated by the illumination light to take an image of an annealed site of the substrate in a linear field of view in the Y direction. In a YZ plan view, the third direction is inclined from a vertical direction, and the fourth direction is inclined from the vertical direction. Further, the present invention also relates to a laser annealing method and a method for manufacturing a semiconductor device.

Description

Technical Field

[0001] This invention relates to a laser annealing apparatus, a laser annealing method, and a method for manufacturing semiconductor devices. Background Technology

[0002] International Patent Publication No. WO2018 / 37756 discloses a laser annealing apparatus for forming polycrystalline silicon thin films. In WO2018 / 37756, a projection lens focuses a laser beam onto a substrate, forming a linear irradiation area. In this way, the amorphous silicon film is crystallized and transformed into a polycrystalline silicon film.

[0003] Furthermore, in International Patent Publication No. WO2018 / 37756, a substrate is illuminated with detection light. A detector detects the detection light passing through the silicon film. In this way, changes in the crystallization state of the polycrystalline silicon film can be evaluated. Summary of the Invention

[0004] In this laser irradiation device, it is desirable to more accurately assess the non-uniformity of laser irradiation.

[0005] Other issues and new features can be identified from the description and accompanying drawings in this specification.

[0006] According to one embodiment, a laser annealing apparatus includes: a laser source configured to generate a laser; an annealing optical system configured to guide the laser to a substrate to form a linear irradiation area on the substrate, viewed from above along a first direction; a moving mechanism configured to change the relative position of the irradiation area with respect to the substrate along a second direction intersecting the first direction when viewed from above; an illumination source configured to generate illumination light for illuminating the substrate along a third direction, the third direction being a direction inclined from the vertical direction when viewed in a direction perpendicular to a plane including the first direction and a vertical direction; and a detector configured to detect detection light reflected by the substrate illuminated by the illumination light along a fourth direction, thereby capturing an annealed portion of the substrate with a linear field of view along the first direction, the fourth direction being inclined from the vertical direction when viewed in a direction perpendicular to a plane including the first direction and a vertical direction.

[0007] According to one embodiment, a laser annealing method includes the following steps: (a) generating a laser using a laser source; (b) guiding the laser to a substrate to form a linear irradiation area on the substrate, viewed from above along a first direction; (c) varying the relative position of the irradiation area with respect to the substrate along a second direction intersecting the first direction when viewed from above; (d) generating illumination light using an illumination source for illuminating the substrate along a third direction, the third direction being a direction inclined from the vertical direction when viewed in a direction perpendicular to a plane including the first direction and the vertical direction; and (e) detecting detection light reflected by the substrate illuminated by the illumination light along a fourth direction using a detector, thereby photographing the annealed portion of the substrate with a linear field of view along the first direction, the fourth direction being inclined from the vertical direction when viewed in a direction perpendicular to a plane including the first direction and the vertical direction.

[0008] According to the described embodiment, the non-uniformity of irradiation can be assessed more accurately. The above and other objects, features, and advantages of this disclosure will be more fully understood from the following detailed description and the illustrative drawings, and should not be considered as limiting the scope of this disclosure. Attached Figure Description

[0009] Figure 1 An optical system for a laser annealing apparatus according to one embodiment is shown;

[0010] Figure 2 This is a schematic plan view of the conveying mechanism of the laser annealing device;

[0011] Figure 3 This is an XZ plane diagram showing the position of the detection unit relative to the substrate;

[0012] Figure 4 This is a YZ plane diagram showing the position of the lighting source relative to the substrate;

[0013] Figure 5 This is a YZ plane diagram showing the position of the detector relative to the substrate;

[0014] Figure 6 It is a simplified diagram used to illustrate diffraction conditions;

[0015] Figure 7 SEM images of polycrystalline silicon films are shown;

[0016] Figure 8 This is a simplified cross-sectional view of the structure of an organic EL (Electro-Luminescent) display;

[0017] Figure 9This is a cross-sectional view showing one step in a method for manufacturing a semiconductor device according to this embodiment;

[0018] Figure 10 This is a cross-sectional view showing one step in a method for manufacturing a semiconductor device according to this embodiment;

[0019] Figure 11 This is a cross-sectional view showing one step in a method for manufacturing a semiconductor device according to this embodiment;

[0020] Figure 12 This is a cross-sectional view showing one step in a method for manufacturing a semiconductor device according to this embodiment;

[0021] Figure 13 This is a cross-sectional view showing one step in a method for manufacturing a semiconductor device according to this embodiment;

[0022] Figure 14 This is a cross-sectional view showing one step in a method for manufacturing a semiconductor device according to this embodiment;

[0023] Figure 15 This is a cross-sectional view showing one step in a method for manufacturing a semiconductor device according to this embodiment; and

[0024] Figure 16 This is a cross-sectional view showing one step in a method for manufacturing a semiconductor device according to this embodiment. Detailed Implementation

[0025] First Implementation Method

[0026] The laser annealing apparatus according to this embodiment is, for example, an ELA (Excimer Laser Annealing) apparatus for forming LTPS (Low Temperature Poly-Silicon) films. The laser annealing apparatus, laser annealing method, and method for manufacturing semiconductor devices according to this embodiment will now be described with reference to the accompanying drawings.

[0027] (Optical system of the ELA device)

[0028] refer to Figure 1 The structure of the ELA device 1 according to this embodiment will be explained. Figure 1The optical system of the ELA device 1 is schematically shown. A silicon film 101 is formed on the upper surface (main surface) of the substrate 100. The ELA device 1 irradiates the silicon film 101 formed on the substrate 100 with a laser L1. In this way, the amorphous silicon film (a-Si film) 101 can be converted into a polycrystalline silicon film (p-Si film) 101. The substrate 100 is, for example, a transparent substrate such as a glass substrate.

[0029] It should be noted that, in Figure 1 For clarity, a three-dimensional orthogonal coordinate system (XYZ) is shown. The Z-direction is vertical and perpendicular to the substrate 100. The XY plane is a plane parallel to the surface of the substrate 100 where the silicon film 101 is formed. The X-direction is the length direction of the rectangular substrate 100, and the Y-direction is the width direction of the substrate 100. Furthermore, in the ELA device 1, when passing through ( Figure 1 When the conveying mechanism (not shown) conveys the substrate 100 along the positive X-axis, the silicon film 101 is irradiated by laser L1. It should be noted that... Figure 1 In this context, the silicon film 101 that has not yet been irradiated by laser L1 is referred to as amorphous silicon film 101a, and the silicon film 101 that has been irradiated by laser L1 is referred to as polycrystalline silicon film 101b.

[0030] ELA device 1 includes a stage 10, a laser light source 21, an annealing optical system 20, a detection unit 30, and a control unit 40. A substrate 100 is disposed on the stage 10, which is a floating stage (floating unit) that allows the substrate 100 to float (i.e., levitate) by jetting air. The stage 10 jets gas towards the substrate 100 from below. Therefore, with a small air gap formed between the stage 10 and the substrate 100, the substrate 100 is transported in the positive X-axis direction.

[0031] The annealing optical system 20 is an optical system used to crystallize the amorphous silicon film 101 by irradiating it with a laser L1. The annealing optical system 20 includes a mirror 22 and a projection lens 23. The annealing optical system 20 is used as an optical system to guide the laser L1 to the substrate 100.

[0032] The annealing optical system 20 is disposed on the upper side of the substrate 100 (on the positive Z-axis side of the substrate 100). The laser source 21 is a pulsed laser source and generates pulsed laser light. The laser source 21 is, for example, an excimer laser source that emits an excimer laser with a center wavelength of 308 nm. Furthermore, the laser source 21 emits pulsed laser light L1. The laser source 21 emits laser light L1 towards the reflector 22.

[0033] A reflector 22 and a projection lens 23 are disposed on the upper side of the substrate 100. The reflector 22 is, for example, a dichroic mirror that selectively allows light to pass through according to the wavelength of the light. The reflector 22 reflects the laser L1.

[0034] The laser L1 is reflected by the mirror 22 and enters the projection lens 23. The projection lens 23 includes multiple lenses for projecting the laser L1 onto the substrate 100, that is, onto the silicon film 101.

[0035] The projection lens 23 focuses the laser L1 onto the substrate 100. The laser L1 forms a linear irradiation area on the substrate 100. That is, on the substrate 100, the laser L1 forms a line beam along the Y direction (also referred to as the first direction). Specifically, the laser L1 focused on the substrate 100 forms a linear irradiation area whose length direction (major axis direction) is parallel to the Y direction and whose width direction (minor axis direction) is parallel to the X direction. Furthermore, when the substrate 100 is transported along the transport direction (also referred to as the second direction), the silicon film 101 is irradiated with the laser L1. In this example, the transport direction is parallel to the X direction. Thus, the laser L1 can be applied to a strip-shaped area whose width corresponds to the length of the irradiation area in the Y direction.

[0036] As described above, the annealing optical system 20 guides the laser L1 emitted from the laser source 21 to the substrate 100. Irradiation by the laser L1 crystallizes the amorphous silicon film 101a. While the portion of the substrate 100 to which the laser L1 is applied changes, the silicon film 101 is irradiated by the laser L1. By transporting the substrate 100 in the positive X-axis direction using the transport mechanism of the stage 10, a uniform polycrystalline silicon film 101b is formed on the substrate 100. It goes without saying that an optical system such as a projection lens can be moved instead of transporting the substrate 100. That is, any configuration or similar measure can be used as long as the irradiated area is scanned by the laser L1 by moving the substrate 100 and the annealing optical system 20 relative to each other.

[0037] Furthermore, a detection unit 30 is disposed above the substrate 100. The detection unit 30 is configured for capturing (i.e., image capturing) the crystallized polycrystalline silicon film 101b. The configuration of the detection unit 30 will be described later.

[0038] The control unit 40 receives the results of the image capture (i.e., image capture) performed by the detection unit 30. The silicon film 101 formed on the substrate 100 has been crystallized by laser L1. The control unit 40 evaluates the crystallization state of the silicon film 101 based on the image capture results from the detector 32. The control unit 40 adjusts the output of the laser source 21 based on this evaluation result. For example, when the crystallization state changes, the control unit 40 increases the output power of the laser source 21. Alternatively, the control unit 40 can control the transport speed of the substrate 100 according to the evaluation result.

[0039] Next, refer to Figure 2 This describes the conveying mechanism used to convey the substrate 100. Figure 2This is a schematic top view showing the configuration for transporting the substrate 100. As described above, the substrate 100 is disposed above the worktable 10. A transport unit 11 is disposed on the positive side of the Y-axis of the worktable 10.

[0040] The worktable 10 is a floating worktable that uses injected gas to make the substrate 100 float (i.e., levitate). The worktable 10 is configured to eject gas from its surface. The gas ejected from the surface of the worktable 10 is blown onto the lower surface (i.e., the underside) of the substrate 100, causing the substrate 100 to float. When transporting the substrate 100, the worktable 10 adjusts the floating height of the substrate 100 by adjusting the amount of injected gas.

[0041] The end of the substrate 100 on the positive Y-axis side protrudes beyond the worktable 10. The conveying unit 11 conveys the floating substrate 100 along the conveying direction (positive X-axis direction). The conveying unit 11 includes a holding mechanism 12 and a moving mechanism 13. The holding mechanism 12 holds the substrate 100. For example, the holding mechanism 12 can be formed using a vacuum adsorption mechanism including porous elements. Alternatively, the holding mechanism 12 can be formed from a metal member having an air inlet. Furthermore, the holding mechanism 12 can be formed using a resin-based material such as PEEK (polyether ether ketone). The holding mechanism 12 (vacuum adsorption mechanism) is connected to an exhaust port (not shown), and this exhaust port is connected to an ejector, vacuum pump, etc. Therefore, since the holding mechanism 12 acts with a negative pressure for drawing in gas, the substrate 100 can be held using the holding mechanism 12.

[0042] In this embodiment, the holding mechanism 12 holds the substrate 100 by attracting the surface of the substrate 100 opposite to the surface of the substrate 100 that is irradiated by the laser (lower surface, i.e., the lower side), i.e., the surface of the substrate 100 opposite to the worktable 10 (upper surface). In addition, the holding mechanism 12 holds the end of the substrate 100 in the positive Y-axis direction (i.e., the end of the substrate 100 in the direction perpendicular to its transport direction).

[0043] The moving mechanism 13, provided in the conveying unit 11, is connected to the holding mechanism 12. The moving mechanism 13 is configured to move the holding mechanism 12 in the conveying direction (in the X direction). The conveying unit 11 (holding mechanism 12 and moving mechanism 13) is provided near the end of the worktable 10 in the positive Y-axis direction. Furthermore, when the holding mechanism 12 holds the substrate 100, the moving mechanism 13 moves in the conveying direction, thereby conveying the substrate 100.

[0044] For example, the moving mechanism 13 is configured to slide the end of the worktable 10 in the positive Y-axis direction along the positive X-axis direction. When the moving mechanism 13 slides the end of the worktable 10 along the positive X-axis direction, the substrate 100 is conveyed in the X direction. It should be noted that the conveying speed of the substrate 100 can be controlled by controlling the moving speed of the moving mechanism 13. The moving mechanism 13 includes, for example, an actuator (such as a motor), a linear guide mechanism, an air bearing, etc. (not shown).

[0045] As described above, the substrate 100 is irradiated with a laser. Figure 2 In the diagram, the irradiated area 15 of laser L1 has a linear shape. The length direction of the irradiated area 15 is parallel to the Y direction.

[0046] Furthermore, a detection area 16 is formed on the positive side of the X-axis of the illumination area 15, where the detection unit 30 detects reflected light. The detection area 16 is a linear region whose length direction is parallel to the Y-direction. The detection area 16 corresponds to the field of view of the detector of the detection unit 30. That is, the detector of the detection unit 30 captures (i.e., captures an image) of the substrate 100 by detecting the reflected light from the detection area 16. Since the substrate 100 is transported in the X-direction, almost the entire surface of the substrate 100 can be captured.

[0047] Furthermore, the detection area 16 is positioned near the irradiation area 15. That is, the irradiation area 15 and the detection area 16 are arranged with a short distance between them in the X direction. Therefore, the portion of the substrate 100 that has been annealed by laser L1 can be photographed during the annealing process. Thus, the control unit 40 can quickly suppress changes in the crystallization state.

[0048] refer to Figures 3 to 5 Explain the configuration of detection unit 30. Figure 3 This is a side view showing the position of the detection unit 30 relative to the substrate 100. Figure 4 This is a front view showing the position of the illumination source 31 of the detection unit 30. Figure 5 This is a front view showing the position of the detector 32 of the detection unit 30. Figure 3 It is an XZ plan view. Figure 4 and Figure 5 This is the YZ plan. Figures 3 to 5 The silicon film 101 formed on the substrate 100 is omitted from the illustration. The detection unit 30 includes an illumination source 31 and a detector 32.

[0049] An illumination source 31 is disposed above the substrate 100, generating illumination light L2 for illuminating the substrate 100. The illumination source 31 is a linear illumination source and forms an illumination area 17 whose length direction is parallel to the Y direction. The illumination source 31 is, for example, an LED lighting device comprising multiple LEDs (Light Emitting Diodes). The illumination light L2 provides uniform illumination. Figure 2 The entire detection area 16 is shown. The illumination light L2 can be white light, or it can be monochromatic light emitted from a laser device or one or more monochromatic LEDs. In this case, the wavelength of the illumination light L2 can be approximately 450 nm.

[0050] The illumination source 31 has a lens array consisting of multiple lenses corresponding to multiple LEDs, and illuminates the substrate 100 in an inclined direction. The optical axis of the illumination light L2 emitted from the illumination source 31 is inclined with respect to the Z direction. The illumination source 31 emits the illumination light L2 in a direction inclined with respect to the upper surface of the substrate 100. As the illumination source 31, for example, the SKLC series manufactured by SHIBASAKI Corporation can be used.

[0051] Detector 32 is disposed above substrate 100. Detector 32 is located offset from the illumination source 31 towards the negative X-axis. Detector 32 detects illumination light reflected by polysilicon film 101b. Illumination light reflected from substrate 100 and traveling towards detector 32 is designated as detection light L3. Detector 32 detects detection light L3 from illumination area 17 illuminated by illumination light L2.

[0052] Detector 32 is a line camera (line sensor) comprising multiple pixels. That is, multiple pixels are arranged in a row along the Y direction on the imaging surface 32a of detector 32. It should be noted that the imaging surface 32a is parallel to the XY plane and faces downwards. Furthermore, detector 32 may include a lens array consisting of multiple lenses corresponding to each pixel.

[0053] like Figure 2 As shown, the field of view of detector 32 constitutes a linear detection region 16 along the Y direction. Detector 32 detects detection light L3 reflected by substrate 100 in an inclined direction. Detector 32 images substrate 100 by using the upper surface of substrate 100 as a focal plane (in-focal plane). The amount of detection light L3 detected by detector 32 varies depending on the crystallization state of substrate 100. Therefore, control unit 40 can evaluate the crystallization state based on the image of substrate 100 captured by detector 32.

[0054] Furthermore, the illumination source 31 is mounted on the rotating mechanism 33. The rotating mechanism 33 rotatably holds the illumination source 31. The rotation axis of the rotating mechanism 33 is parallel to the Y direction. That is, the rotating mechanism 33 causes the illumination source 31 to rotate about the Y-axis. As a result, the incident direction of the illumination light L2 onto the substrate 100 can be adjusted. The rotating mechanism 33 rotates the illumination source 31 to change the angle of the optical axis of the illumination light L2.

[0055] The following details the direction in which the illumination light L2 is incident on the substrate 100 (hereinafter referred to as the third direction) and the direction in which the reflected light detected by the detector 32 is reflected (hereinafter referred to as the fourth direction). The third direction is the direction in which the illumination light L2 travels near the substrate 100. The third direction is the direction in which the illumination light L2 is incident on the substrate 100. That is, on the upper surface of the substrate 100, the third direction is the direction of the optical axis (central axis) of the illumination light optical system from the illumination source 31 toward the substrate 100. The illumination light L2 is incident on the substrate 100 along the third direction. The illumination source 31 is tilted such that the illumination light L2 is incident on the substrate 100 along the third direction.

[0056] When viewed from above in the YZ direction (i.e., in a direction perpendicular to the YZ plane), the third third direction is tilted relative to the upper surface of the substrate 100. When viewed from above in the YZ direction, the third third direction is tilted relative to the Z direction. Therefore, the illumination area 17 of the substrate 100 is offset from the area directly below the illumination source 31 in the positive Y-axis direction. When viewed from above in the XY direction (i.e., in a direction perpendicular to the XY plane), the angle between the Y direction and the third third direction is determined by θ. light Representation. Angle θ light For example, it could be 20° to 30°.

[0057] The illumination light L2 is incident obliquely on the substrate 100. Furthermore, when viewed from above in the XZ direction (i.e., in a direction perpendicular to the XZ plane), the third direction is oblique relative to the Z direction. The illumination area 17 of the substrate 100 is offset in the X direction from the area directly below the illumination source 31.

[0058] Detector 32 detects the detection light L3 reflected from substrate 100 in a fourth direction. The fourth direction is the direction in which the reflected light travels towards the detector on the upper surface of substrate 100 (i.e., on the polysilicon film 101b). Therefore, the detection light L3 traveling along the fourth direction is detected by detector 32; for example, the fourth direction is the direction of the optical axis of the imaging optics system of detector 32. The detection light L3 is incident on detector 32 along the fourth direction. Detector 32 detects the detection light L3 reflected from substrate 100 in the fourth direction. Detector 32 is positioned to detect the detection light L3 reflected from substrate 100 in the fourth direction.

[0059] When viewed from above in a YZ top view, the fourth direction is tilted relative to the upper surface of the substrate 100. When viewed from above in a YZ top view, the fourth direction is tilted relative to the Z direction. Therefore, the detection area 16 of the substrate 100 is offset from the area directly below the detector 32 in the positive Y-axis direction. When viewed from above in an XY top view, the angle between the Y direction and the fourth direction is determined by θ. camera Representation. Angle θ camera For example, it could be approximately 70°.

[0060] Although the imaging surface 32a of detector 32 is parallel to the upper surface (focal plane) of substrate 100, the detection light L3 is a beam incident obliquely onto the imaging surface 32a of detector 32. When viewed from above in the XZ direction, the fourth direction is parallel to the Z direction. In the X direction, the detection area 16 of substrate 100 coincides with the area directly below detector 32. It should be noted that when viewed from above in the XZ direction, the fourth direction can be tilted relative to the Z direction.

[0061] The amount of detection light L3 detected by detector 32 depends on the angle θ light and θ camera This changes the detection result. Specifically, the detection light L3 from the polycrystalline silicon film 101b interferes with each other, altering the detection result. Specifically, the angle θ... light and θ camera It satisfies the relationship that easily generates interference light. Therefore, changes in the crystallization state can be accurately assessed.

[0062] Figure 6 It is a diagram used to illustrate the relationship between the generation of interference light. Figure 6 This illustrates a reflective diffraction grating with grooves formed on the surface of a substrate. The grooves are formed perpendicular to the plane of the paper. The period of the protrusions / recesses is denoted by d, and the wavelength of the light is denoted by λ. The angle of light incident on the top surface of the protrusion is denoted by θ. α This means that the angle of the detection light is θ. β It is indicated that interference light is observed when the relationship represented by equation (1) shown below is satisfied.

[0063] dcosθ α -dcosθ β =(λ / 2)×2n (1)

[0064] It should be noted that n is an integer equal to or greater than zero. The way in which non-uniformity is observed (i.e., how non-uniformity is observed) changes according to the fourth direction (the direction of observation). That is, when the angle θ α and θ β When the above relationship is satisfied, the light rays are in phase and thus reinforce each other. Therefore, by setting the third and fourth directions at predetermined angles, variations in crystal size can be accurately evaluated.

[0065] Figure 7 An SEM image of the crystallized silicon film 101 is shown. As described above, the laser L1 forms a linear irradiation region 15 on the substrate 100 along the Y direction. Furthermore, the laser L1 is a pulsed light, and the substrate 100 is transported in the X direction.

[0066] The crystal size varies relatively little in the Y direction, while it varies relatively much in the X direction. That is, due to the uniform and regular arrangement of the crystals in the Y direction, the crystal size is highly uniform. Because of this uniform arrangement in the Y direction, the interference light tends to be enhanced. Simultaneously, due to the poor arrangement of the crystals in the X direction, the interference light tends to be weakened.

[0067] Therefore, in this embodiment, when viewed from above in the YZ direction, the third and fourth directions are tilted relative to the Z direction. This allows for the detection of interference light that is strongly correlated with the inhomogeneity of the crystallization state. That is, when the crystal size is inconsistent, the phases of the detection light L3 are different and do not reinforce each other. In other words, the amount of detection light L3 varies greatly depending on the crystal size. Therefore, by tilting the illumination source 31 and the detector 32, changes in the crystallization state can be accurately assessed. The inhomogeneity of the laser L1 illumination can be correctly assessed. For example, the changes between laser L1 pulses can be accurately assessed.

[0068] Therefore, the optimized energy density (OED) of the laser L1 can be determined during the laser annealing process. Furthermore, the control unit 40 determines the output of the laser source 21 to achieve the optimal energy density. This allows the silicon film 101 to be annealed at the optimal energy density, thereby improving productivity.

[0069] The crystal size corresponds to the period d of the groove in equation (1). The angle θ that easily generates interference light is set according to the crystal size in the Y direction. light and θ camera That is, the illumination source 31 and the detector 32 are arranged at an angle such that the reflected light from adjacent crystals becomes the same phase, thus mutually reinforcing each other. Preferably, the angle θ is... light and θ camera The detector 32 and the illumination source 31 are configured to detect interference light of orders other than zero. For example, the detector 32 and the illumination source 31 are configured to detect interference light of orders of positive and negative first order (N = ±1) and interference light of orders of positive and negative second order (N = ±2).

[0070] In the above description, the fourth direction is determined by the angle at which the detector 32 is positioned, but the fourth direction can also be determined (i.e., set) by providing an optical element, such as a mirror, between the substrate 100 and the detector 32. Similarly, the third direction is determined by the angle at which the illumination source 31 is positioned, but the third direction can also be determined by providing an optical element, such as a mirror, between the substrate 100 and the illumination source 31.

[0071] As described above, the illumination source 31 generates illumination light L2 to illuminate the substrate 100 along the third direction. The detector 32 detects the detection light L3 reflected from the substrate 100 illuminated by the illumination light L2 in the fourth direction, thereby photographing the annealed portion of the substrate 100 with a linear field of view along the Y direction. When viewed from above in the YZ direction, the third direction is tilted relative to the Z direction (vertical direction), and the fourth direction is also tilted relative to the Z direction (vertical direction). In this way, inhomogeneities in the crystallization state can be accurately evaluated.

[0072] The preferred detector 32 has a wider field of view than the irradiated area 15. This allows for the evaluation of the crystallization state of the entire annealed portion of the substrate 100. Furthermore, in Figure 2 In this configuration, the detection area 16 and the illumination area 15 of the detector 32 almost cover the entire substrate 100 in the Y direction, but may only cover a portion of the substrate 100. In this case, whenever the substrate 100 is transported in the X direction, it can be transported two or more times in the X direction while simultaneously moving the substrate 100 in position in the Y direction.

[0073] It should be noted that the conveying unit 11 conveys the substrate 100 in the X direction, which is orthogonal to the Y direction, but the conveying direction does not necessarily have to be precisely perpendicular to the Y direction. That is, as long as the conveying direction intersects the Y direction, it does not have to be precisely perpendicular to the Y direction. Furthermore, the material annealed by laser L1 is not limited to silicon films.

[0074] In this embodiment, the stage 10 is a floating stage that floats (i.e., levitates) the substrate 100. A moving mechanism moves the substrate 100 in the X direction above the floating stage. This prevents the detection of reflected light from the surface of the stage 10, thereby enabling accurate evaluation of the crystallization state.

[0075] In the laser annealing method according to this embodiment, a laser L1 is generated using a laser light source 21. The laser L1 is guided to a substrate 100 to form a linear irradiation area 15 along the Y direction when viewed from above (i.e., from above). When viewed from above, the position of the irradiation area 15 relative to the substrate 100 varies along the X direction, which intersects the Y direction. An illumination light L2 is generated using an illumination light source 31 to illuminate the substrate 100 along a third direction. A detector 32 detects the detection light L3 reflected in a fourth direction from the substrate 100 illuminated by the illumination light L2, thereby capturing a linear field of view along the Y direction of the annealed portion of the substrate 100. When viewed from above in the YZ direction, the third direction is tilted relative to the Z direction. When viewed from above in the YZ direction, the fourth direction is tilted relative to the Z direction. This allows for accurate assessment of irradiation non-uniformity.

[0076] (Organic EL display)

[0077] Semiconductor devices with the aforementioned polycrystalline silicon film are suitable for thin-film transistor (TFT) array substrates used in organic electroluminescence (EL) displays. Specifically, the polycrystalline silicon film serves as the semiconductor layer, which has the source region, channel region, and drain region of the TFT.

[0078] The following describes an example of using the semiconductor device according to this embodiment in an organic EL display. Figure 8 This is a simplified cross-sectional view of the pixel circuitry of an organic EL display device. Figure 8 The organic EL display device 300 shown is an active matrix display device with a TFT in each pixel PX.

[0079] The organic EL display device 300 includes a substrate 310, a TFT layer 311, an organic layer 312, a color filter layer 313, and a sealing substrate 314. Figure 9 This diagram illustrates a top-radiating organic EL display device with the sealing substrate 314 side located on the viewing side. It should be noted that the following description illustrates one configuration example of the organic EL display device, and this embodiment is not limited to the configuration described below. For example, the semiconductor device according to this embodiment can be used in a bottom-radiating organic EL display device.

[0080] The substrate 310 is a glass substrate or a metal substrate. A TFT layer 311 is disposed on the substrate 310. The TFT layer 311 includes TFTs 311a disposed in each pixel PX. In addition, the TFT layer 311 includes wiring (not shown) connected to the TFTs 311a. The TFTs 311a, wiring, etc. constitute a pixel circuit.

[0081] An organic layer 312 is disposed on the TFT layer 311. The organic layer 312 includes an organic EL light-emitting element 312a disposed in each pixel PX. The organic EL light-emitting element 312a may have, for example, a stacked structure consisting of an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode. In the case of a top-radiating type, the anode is a metal electrode, and the cathode is a transparent conductive film made of ITO (Indium Tin Oxide) or the like. Furthermore, in the organic layer 312, partition walls 312b are provided between each pixel PX to separate the organic EL light-emitting elements 312a.

[0082] A color filter layer 313 is disposed on the organic layer 312. The color filter layer 313 includes color filters 313a for color display. That is, in each pixel PX, a resin layer colored R (red), G (green), and B (blue) is disposed as a color filter 313a. When white light emitted from the organic layer 312 passes through the color filter 313a, the white light is converted into light with RGB colors. It should be noted that if the organic layer 312 is provided with a three-color system of organic EL light-emitting elements capable of emitting various colors of RGB, the color filter layer 313 may be unnecessary.

[0083] A sealing substrate 314 is disposed on the color filter layer 313. The sealing substrate 314 is a transparent substrate such as a glass substrate, and is disposed to prevent the organic EL light-emitting element of the organic layer 312 from deteriorating.

[0084] The current flowing to the organic EL light-emitting element 312a in the organic layer 312 is changed by a display signal supplied to the pixel circuit. Therefore, by supplying a display signal corresponding to the displayed image to each pixel PX, the amount of light emitted in each pixel PX can be controlled. As a result, the desired image can be displayed.

[0085] In active-matrix display devices, such as organic EL displays, each pixel PX has one or more TFTs (e.g., switching TFTs and driving TFTs). Furthermore, each pixel PX's TFT has a semiconductor layer having a source region, a channel region, and a drain region. The polycrystalline silicon film according to this embodiment is suitable as the semiconductor layer of the TFT. That is, by using the polycrystalline silicon film manufactured by the above-described manufacturing method as the semiconductor layer of the TFT array substrate, in-plane non-uniformity, a characteristic of TFTs, can be suppressed. Therefore, display devices with excellent display characteristics can be manufactured with high productivity.

[0086] (Manufacturing method for semiconductor devices)

[0087] The method for manufacturing semiconductor devices using an ELA device according to this embodiment is suitable for manufacturing TFT array substrates. Reference Figures 9 to 16Describe a method for manufacturing semiconductor devices including TFTs. Figures 9 to 16 This is a cross-sectional view showing the process of manufacturing a semiconductor device. The following description explains a method for manufacturing a semiconductor device having anti-interlaced TFTs.

[0088] First, such as Figure 9 As shown, a gate electrode 402 is formed on a glass substrate 401. It should be noted that the glass substrate 401 corresponds to the substrate 100 described above. For example, a metal thin film containing aluminum can be used as the gate electrode 402. The metal thin film is formed on the glass substrate 401 by sputtering or deposition. Then, the metal thin film is patterned by photolithography to form the gate electrode 402. In the photolithography process, steps such as photoresist coating, exposure, development, etching, and photoresist stripping are performed. It should be noted that various types of wiring can be formed in the same steps as patterning the gate electrode 402.

[0089] Next, as Figure 10 As shown, a gate insulating film 402 is formed on the gate electrode 403. The gate insulating film 403 is formed to cover the gate electrode 402. Then, as... Figure 11 As shown, an amorphous silicon film 404 is formed on the gate insulating film 403. The amorphous silicon film 404 is configured to overlap with the gate electrode 402 through the gate insulating film 403.

[0090] The gate insulating film 403 is a silicon nitride film (SiN). x The film may be a silicon oxide film (SiO2 film) or a laminate of the two. Specifically, a gate insulating film 403 and an amorphous silicon film 404 are continuously formed by chemical vapor deposition (CVD).

[0091] Then, as Figure 12 As shown, an amorphous silicon film 404 is irradiated with laser L1 to form a polycrystalline silicon film 405. That is, through... Figure 1 The ELA device 1 shown in the figure crystallizes the amorphous silicon film 404. As a result, a polycrystalline silicon film 405 having crystalline silicon is formed on the gate insulating film 403. The polycrystalline silicon film 405 corresponds to the polycrystalline silicon film 101b described above.

[0092] At this time, the polycrystalline silicon film 405 is inspected according to the inspection method of this embodiment. When the polycrystalline silicon film 405 does not meet the predetermined standard, it is irradiated with a laser again. Therefore, the characteristics of the polycrystalline silicon film 405 can be further homogenized. Since in-plane non-uniformity can be suppressed, display devices with excellent display characteristics can be manufactured with high productivity.

[0093] It should be noted that, although not shown, the polycrystalline silicon film 405 is patterned using photolithography. Furthermore, impurities can be introduced into the polycrystalline silicon film 405 using methods such as ion implantation.

[0094] Then, as Figure 13 As shown, an interlayer insulating film 406 is formed on the polysilicon film 405. The interlayer insulating film 406 is provided with contact holes 406a for exposing the polysilicon film 405.

[0095] Interlayer insulating film 406 is silicon nitride film (SiN) x The interlayer insulating film 406 is formed by chemical vapor deposition (CVD). Then, the interlayer insulating film 406 is patterned by photolithography to form contact holes 406a.

[0096] Next, as Figure 14 As shown, a source electrode 407a and a drain electrode 407b are formed on the interlayer insulating film 406. The source electrode 407a and the drain electrode 407b are formed in a manner that covers the contact hole 406a. That is, the source electrode 407a and the drain electrode 407b are formed from the inside of the contact hole 406a to the top of the interlayer insulating film 406. Therefore, the source electrode 407a and the drain electrode 407b are electrically connected to the polysilicon film 405 through the contact hole 406a.

[0097] This forms TFT 410. TFT 410 corresponds to TFT 311a described above. In the polysilicon film 405, the region overlapping with the gate electrode 402 is the channel region 405c. The source electrode 407a side of the polysilicon film 405 compared to the channel region 405c is the source region 405a, and the drain electrode 407b side is the drain region 405b.

[0098] The source electrode 407a and drain electrode 407b are formed from a metal thin film containing aluminum. The metal thin film is formed on the interlayer insulating film 406 by sputtering or deposition. Then, the metal thin film is patterned by photolithography to form the source electrode 407a and drain electrode 407b. It should be noted that various types of wiring can be formed in the same process as the patterning of the source electrode 407a and drain electrode 407b.

[0099] Then, as Figure 15 As shown, a planarization film 408 is formed on the source electrode 407a and the drain electrode 407b, and the planarization film 408 is formed to cover the source electrode 407a and the drain electrode 407b. The planarization film 408 is provided with a contact hole 408a for exposing the drain electrode 407b.

[0100] The planarization film 408 is, for example, made of a photosensitive resin film. The photosensitive resin film is coated on the source electrode 407a and the drain electrode 407b, and then exposed and developed. This allows the planarization film 408, which has contact holes 408a, to be patterned.

[0101] Then, as Figure 16 As shown, a pixel electrode 409 is formed on the planarization film 408. The pixel electrode 409 is formed to cover the contact hole 408a. That is, the pixel electrode 409 extends from the inside of the contact hole 408a to the top of the planarization film 408. Therefore, the pixel electrode 409 is electrically connected to the drain electrode 407b through the contact hole 408a.

[0102] The pixel electrode 409 is formed from a transparent conductive film or a metal thin film containing aluminum. The conductive film (transparent conductive film or metal thin film) is formed on the planarization film 408 by sputtering. Then, the conductive film is patterned by photolithography. Thus, the pixel electrode 409 is formed on the planarization film 408. In the case of a TFT for driving an organic EL display, a pattern is formed on the pixel electrode 409 as shown in the image. Figure 8 The organic EL light-emitting device 312a and color filter (CF) 313a are shown. It should be noted that in the case of a top-radiating organic EL display, the pixel electrode 409 is formed of a metal thin film containing aluminum or silver with high reflectivity. In the case of a bottom-radiating organic EL display, the pixel electrode 409 is formed of a transparent conductive film such as ITO.

[0103] The process for manufacturing an anti-interlaced TFT has been described. The manufacturing method according to this embodiment can be applied to the manufacture of anti-interlaced TFTs. Clearly, the manufacturing method for TFTs is not limited to TFTs for organic EL displays, but can also be applied to the manufacture of TFTs for liquid crystal displays (LCDs).

[0104] Furthermore, while the above description illustrates that the laser annealing apparatus according to this embodiment irradiates an amorphous silicon film with a laser to form a polycrystalline silicon film, the same laser annealing apparatus can also irradiate an amorphous silicon film with a laser to form a microcrystalline silicon film. Moreover, the laser used for annealing is not limited to an excimer laser. Furthermore, the method according to this embodiment can be applied to laser annealing apparatuses that crystallize thin films other than silicon films. That is, the method according to this embodiment can be applied as long as the laser annealing apparatus irradiates an amorphous film with a laser to form a crystalline film. With the laser annealing apparatus according to this embodiment, substrates with crystalline films can be properly inspected.

[0105] This disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of this disclosure.

[0106] Based on the disclosure described above, it is obvious that the various embodiments of this disclosure can be modified in many ways. These modifications should not be considered a departure from the spirit and scope of this disclosure, and all such modifications that are obvious to those skilled in the art are included within the scope of the appended claims.

Claims

1. A laser annealing apparatus, comprising: A floating worktable, configured to float a substrate; A laser source configured to generate a laser for crystallizing a film on a substrate; An annealing optical system configured to direct the laser to a substrate floating above the floating stage to form a linear irradiation area on the substrate that is viewed from above along a first direction. A moving mechanism is configured to move a substrate floating above the floating worktable along a second direction that intersects the first direction when viewed from above, thereby changing the relative position of the irradiated area relative to the substrate. An illumination source is configured to generate illumination light for illuminating the substrate along a third direction, wherein the illumination light performs linear illumination to form a linear illumination area along the first direction on the substrate floating above the floating worktable, the third direction being a direction inclined relative to the vertical direction and the first direction when viewed in a direction perpendicular to a plane including the first direction and the vertical direction. as well as A detector is configured to detect detection light reflected along a fourth direction from a substrate floating above the floating stage and illuminated by the illumination light, thereby photographing the annealed portion of the substrate with a linear field of view along the first direction, wherein the fourth direction is tilted relative to the vertical direction and the first direction when viewed in a direction perpendicular to a plane including the first direction and the vertical direction.

2. The laser annealing apparatus according to claim 1, wherein, In the first direction, the detector has a wider field of view than the area illuminated by the laser.

3. The laser annealing apparatus according to claim 1 or 2, wherein, The detector's imaging surface is parallel to the surface of the substrate, and the detector includes a plurality of pixels arranged along the first direction.

4. The laser annealing apparatus according to claim 1 or 2, wherein, The non-uniformity of the crystallization state of the film is evaluated based on the results captured by the detector, and The output of the laser source is adjusted based on the results of the evaluation.

5. The laser annealing apparatus according to claim 1 or 2, wherein, The laser annealing apparatus also has a rotating mechanism that rotates the illumination source around the first direction to change the angle between the vertical direction and the third direction.

6. A laser annealing method, comprising the following steps: (a) Using a laser source to generate a laser for crystallizing a film on a substrate; (b) The laser is directed to a substrate floating above a floating worktable to form a linear irradiation area on the substrate that is viewed from above along a first direction; (c) Move the substrate floating above the floating worktable along a second direction that intersects the first direction when viewed from above, thereby changing the relative position of the irradiated area with respect to the substrate; (d) Using an illumination source to generate illumination light for illuminating the substrate along a third direction, wherein the illumination light performs linear illumination to form a linear illumination area along the first direction on the substrate floating above the floating stage, the third direction being a direction inclined relative to the vertical direction and the first direction when viewed in a direction perpendicular to a plane including the first direction and the vertical direction; and (e) The detection light reflected by the substrate, which is floating above the floating worktable and illuminated by the illumination light, along the fourth direction is detected by the detector, thereby photographing the annealed portion of the substrate with a linear field of view along the first direction. When viewed in a direction perpendicular to the plane including the first direction and the vertical direction, the fourth direction is tilted relative to the vertical direction and the first direction.

7. The laser annealing method according to claim 6, wherein, In the first direction, the detector has a wider field of view than the area illuminated by the laser.

8. The laser annealing method according to claim 6 or 7, wherein, The detector's imaging surface is parallel to the surface of the substrate, and the detector includes a plurality of pixels arranged along the first direction.

9. The laser annealing method according to claim 6 or 7, wherein, The non-uniformity of the crystallization state of the film is evaluated based on the results captured by the detector, and The output of the laser source is adjusted based on the results of the evaluation.

10. The laser annealing method according to claim 6 or 7, wherein, The rotating mechanism causes the lighting source to rotate around the first direction to change the angle between the vertical direction and the third direction.

11. A method for manufacturing a semiconductor device, wherein, Includes the following steps: (S1) An amorphous film is formed on the substrate; as well as (S2) Annealing the amorphous film to crystallize it, thereby forming a crystalline film, wherein, The annealing step (S2) includes: (A) Using a laser light source to generate laser light; (B) The laser is directed to the substrate floating above the floating worktable to form a linear irradiation area on the substrate that is viewed from above along a first direction; (C) Move the substrate floating above the floating worktable along a second direction that intersects with the first direction when viewed from above, thereby changing the relative position of the irradiated area with respect to the substrate; (D) Using an illumination source to generate illumination light for illuminating the substrate floating above the floating stage along a third direction, wherein the illumination light performs linear illumination to form a linear illumination area along the first direction on the substrate floating above the floating stage, the third direction being a direction inclined relative to the vertical direction and the first direction when viewed in a direction perpendicular to a plane including the first direction and the vertical direction; and (E) The detection light reflected by the substrate, which is floating above the floating worktable and illuminated by the illumination light, along the fourth direction is detected by the detector, thereby photographing the annealed portion of the substrate with a linear field of view along the first direction. When viewed in a direction perpendicular to the plane including the first direction and the vertical direction, the fourth direction is tilted relative to the vertical direction and the first direction.

12. The method for manufacturing a semiconductor device according to claim 11, wherein, In the first direction, the detector has a wider field of view than the area illuminated by the laser.

13. The method of manufacturing a semiconductor device according to claim 11 or 12, wherein, The detector's imaging surface is parallel to the surface of the substrate, and the detector includes a plurality of pixels arranged along the first direction.

14. The method of manufacturing a semiconductor device according to claim 11 or 12, wherein, The non-uniformity of the crystallization state of the film is evaluated based on the results captured by the detector, and The output of the laser source is adjusted based on the results of the evaluation.

15. The method of manufacturing a semiconductor device according to claim 11 or 12, wherein, The rotating mechanism causes the lighting source to rotate around the first direction to change the angle between the vertical direction and the third direction.

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