Observation device and substrate processing apparatus

Abstract

To provide an observation device capable of satisfactorily imaging an observed part such as a peripheral part of a semiconductor wafer, and a substrate processing apparatus including the observation device.SOLUTION: An observation device observing an observed part of an observed object and a substrate processing apparatus including the observation device are provided. In the observation device, a diffusion illumination part of a head part arranged close to the observed part diffuses primary illumination light to generate secondary illumination light. The observed part is illuminated with the secondary illumination light and the observation part is observed by reception of reflected light reflected by the observed part. In particular, the diffusion illumination part includes a uniform diffuse reflection surface having characteristics similar to Lambert reflection, and performs diffusion by the uniform diffuse reflection surface to generate the secondary illumination light.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to an observation apparatus for observing an object to be observed, such as a semiconductor wafer, and a substrate processing apparatus that utilizes the observation apparatus. [Background technology]

[0002] There are known processing systems that perform various processes on the peripheral portion of an object to be observed, such as a semiconductor wafer. For example, in Patent Document 1, a coating material is spread on a substrate, and then the bevel portion of the substrate is cleaned. After the bevel cleaning process, an inspection process is performed in which the surface condition of the bevel portion is observed to determine whether or not the coating material is present on the bevel portion. This inspection process is performed by an apparatus different from the apparatus that performs the bevel cleaning process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-139492 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the system described in Patent Document 1, the substrate processing apparatus that performs the bevel cleaning process and the inspection apparatus that performs the inspection process are separated from each other. This causes a time lag between when a defect occurs in the substrate processing apparatus and when the defect is discovered by the inspection apparatus. This can be a factor in reducing the yield.

[0005] In order to solve the above problem, it is conceivable to incorporate an observation device into the substrate processing apparatus. However, the observation device arranges a CMOS (Complementary Metal Oxide Semiconductor) camera on the peripheral edge of the substrate, and observes the peripheral edge of the substrate with the camera. In addition, when inspecting the surface condition of the bevel portion, a camera for observing the bevel portion from various directions and a light source for illuminating the bevel portion from various directions corresponding to the camera are required. In other words, in the conventional observation device, the components arranged near the peripheral edge of the substrate are relatively large, and it is difficult to incorporate the observation device into the substrate processing apparatus.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide an observation apparatus capable of satisfactorily observing an observation portion such as a peripheral portion of a semiconductor wafer, and a substrate processing apparatus equipped with the observation apparatus. [Means for solving the problem]

[0007] A first aspect of the present invention is an observation device for observing an observed portion of an object under observation, characterized in that it comprises an illumination optical system which irradiates primary illumination light near the observed portion, a diffusion illumination unit which diffuses the primary illumination light near the observed portion using an even-diffuse reflecting surface having characteristics approximating Lambertian reflection, a head unit which irradiates and illuminates the observed portion with the diffuse light generated by the even-diffuse reflecting surface as secondary illumination light, and an observation optical system which receives light reflected by the observed portion illuminated by the secondary illumination light and observes the observed portion.

[0008] In addition, a second aspect of the present invention is a substrate processing apparatus comprising: a rotation mechanism for holding and rotating a substrate; a processing mechanism for supplying a processing liquid to the peripheral portion of the substrate rotated by the rotation mechanism to process the peripheral portion of the substrate; and an observation device for observing the peripheral portion before or after processing the peripheral portion, wherein the observation device comprises an illumination optical system for irradiating primary illumination light near the peripheral portion, and a diffusion illumination unit for diffusing the primary illumination light near the peripheral portion using an even-diffuse reflecting surface having characteristics approximating Lambertian reflection, a head unit for irradiating and illuminating the peripheral portion with the diffused light generated by the even-diffuse reflecting surface as secondary illumination light, and an observation optical system for receiving reflected light reflected from the peripheral portion illuminated by the secondary illumination light to observe the peripheral portion.

[0009] In these inventions, the head unit is positioned near the observation area (including the peripheral portion of the substrate). Primary illumination light is irradiated onto the diffuse illumination unit of the head unit, and the diffuse light generated by the diffuse illumination unit is irradiated onto the observation area as secondary illumination light. The diffuse illumination unit has an even-diffuse reflecting surface with characteristics similar to Lambertian reflection, and diffuses the primary illumination light. As a result, as will be described later with reference to FIG. 10, the brightness of the specularly reflected light contained in the secondary illumination light is suppressed, improving the quality of the observation image. Effect of the Invention

[0010] According to the present invention, an observation apparatus capable of satisfactorily observing an observation portion of an object to be observed can be obtained. Furthermore, the use of the observation apparatus makes it easy to incorporate the observation apparatus into a substrate processing apparatus. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing a substrate processing system equipped with an embodiment of a substrate processing apparatus according to the present invention; [Diagram 2] FIG. 1 is a diagram illustrating a schematic configuration of a substrate processing apparatus. [Diagram 3] 2 is a plan view of a portion of the substrate processing apparatus as viewed from above. FIG. [Figure 4] 1 is a diagram illustrating an example of the shape of a peripheral portion of a substrate to be imaged; [Diagram 5] 4 is a block diagram showing an electrical configuration of the substrate processing apparatus shown in FIGS. 2 and 3. FIG. [Figure 6] FIG. 2 is a perspective view showing a head portion of the imaging mechanism. [Figure 7] FIG. 2 is a diagram illustrating a typical progression of light that contributes to top-side imaging. [Figure 8] FIG. 13 is a diagram illustrating a typical progression of light that contributes to side imaging. [Figure 9] 4 is a diagram showing a schematic image of a peripheral portion of a substrate captured by an imaging section; FIG. [Figure 10] 10A and 10B are diagrams illustrating a state in which specular reflected light and diffused light are generated when primary illumination light is irradiated onto a diffuse illumination unit. [Figure 11] FIG. 4 is a diagram showing an example of an image obtained by capturing an image of a peripheral portion of a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 1 is a diagram showing a substrate processing system equipped with an embodiment of a substrate processing apparatus according to the present invention. The substrate processing system 200 includes a substrate processing section 210 that processes substrates S, and an indexer section 220 that is coupled to the substrate processing section 210. The indexer section 220 is configured to receive a container C for accommodating the substrates S (FOUP (Front Opening Unified Pod) that accommodates multiple substrates S in a sealed state, SMIF (Standard Insulation Folding Insertion Facility) that accommodates multiple substrates S in a sealed state, etc.). The system is equipped with a container holder 221 capable of holding a plurality of substrates (e.g., pods, OCs (Open Cassettes), etc.), and an indexer robot 222 for accessing the containers C held by the container holder 221 to take out unprocessed substrates S from the container C or store processed substrates S in the container C. Each container C contains a plurality of substrates S in a substantially horizontal position.

[0013] In this specification, the pattern-formed surface (one main surface) of both main surfaces of the substrate S on which a pattern is formed is referred to as the "front surface," and the other main surface on the opposite side on which no pattern is formed is referred to as the "rear surface." The surface facing downward is referred to as the "lower surface," and the surface facing upward is referred to as the "upper surface." In this specification, the "pattern-formed surface" refers to the surface of the substrate on which a concave-convex pattern is formed in any region.

[0014] The indexer robot 222 comprises a base 222a fixed to the device housing, an articulated arm 222b rotatably provided around a vertical axis relative to the base 222a, and a hand 222c attached to the tip of the articulated arm 222b. The hand 222c is structured so that a substrate S can be placed on its upper surface and held thereon. Indexer robots having such articulated arms and hands for holding substrates are well known, and therefore detailed description thereof will be omitted.

[0015] The substrate processing section 210 includes a substrate transfer robot 211 disposed approximately at the center in a plan view, and a plurality of processing units 1 disposed to surround the substrate transfer robot 211. Specifically, the plurality of processing units 1 are disposed facing the space in which the substrate transfer robot 211 is disposed. The main components of the processing units 1 are installed inside the processing chamber 100. The substrate transfer robot 211 accesses these processing units 1 at appropriate times to transfer the substrate S. Meanwhile, each processing unit 1 performs a predetermined process on the substrate S. In this embodiment, one of these processing units 1 corresponds to the substrate processing apparatus according to the present invention.

[0016] FIG. 2 is a diagram showing a schematic configuration of a substrate processing apparatus. FIG. 3 is a plan view of a part of the substrate processing apparatus seen from above. FIG. 4 is a diagram showing an example of the shape of the peripheral portion of a substrate to be imaged. FIG. 5 is a block diagram showing an electrical configuration of the substrate processing apparatus shown in FIGS. 2 and 3. In FIGS. 2, 3 and each of the figures referred to below, the dimensions and numbers of each part may be exaggerated or simplified for ease of understanding. In addition, in order to clarify the directional relationships, each figure is appropriately provided with a coordinate system in which the Z axis is the vertical direction and the XY plane is the horizontal plane.

[0017] The substrate processing apparatus (processing unit) 1 includes a rotation mechanism 2, a scattering prevention mechanism 3, a processing mechanism 4, a peripheral heating mechanism 5, and an imaging mechanism 6. These components 2 to 6 are housed in an internal space 101 of a processing chamber 100 and are electrically connected to a control unit 9 that controls the entire apparatus. The components 2 to 6 operate in response to instructions from the control unit 9.

[0018] The control unit 9 may be, for example, a device similar to a general computer. That is, in the control unit 9, a CPU serving as an arithmetic processing unit 91 performs arithmetic processing according to a procedure described in a program, thereby controlling each part of the substrate processing apparatus 1. As a result, the substrate processing apparatus 1 supplies a processing liquid to the peripheral part of the upper surface of the substrate S in the processing chamber to perform a bevel etching process. The detailed configuration and operation of the control unit 9 will be described later. In this embodiment, the control unit 9 is provided for each substrate processing apparatus 1, but a configuration may be adopted in which a single control unit controls a plurality of substrate processing apparatuses 1. In addition, a configuration may be adopted in which the substrate processing apparatus 1 is controlled by a control unit (not shown) that controls the entire substrate processing system 200.

[0019] The rotation mechanism 2 rotates the substrate S in a rotation direction AR1 (FIG. 3) while holding it in a substantially horizontal position with its surface facing upward. The rotation mechanism 2 rotates the substrate S around a vertical rotation axis AX passing through the center of the main surface of the substrate S. The rotation mechanism 2 includes a spin chuck 21, which is a disk-shaped member smaller than the substrate S. The spin chuck 21 is provided so that its upper surface is substantially horizontal and its central axis coincides with the rotation axis AX. A rotation shaft portion 22 is connected to the lower surface of the spin chuck 21. The rotation shaft portion 22 extends in the vertical direction with its axis line coinciding with the rotation axis AX. A rotation drive portion (e.g., a motor) 23 is connected to the rotation shaft portion 22. The rotation drive portion 23 drives the rotation shaft portion 22 to rotate around its axis line in response to a rotation command from the control unit 9. Therefore, the spin chuck 21 can rotate around the rotation axis AX together with the rotation shaft portion 22. The rotation drive unit 23 and the rotation shaft unit 22 function to rotate the spin chuck 21 about the rotation axis AX.

[0020] A through hole (not shown) is provided in the center of the spin chuck 21, and communicates with the internal space of the rotating shaft portion 22. A pump 24 (FIG. 5) is connected to the internal space through a pipe in which a valve (not shown) is interposed. The pump 24 and the valve are electrically connected to the control unit 9 and operate according to commands from the control unit 9. This allows negative pressure and positive pressure to be selectively applied to the spin chuck 21. For example, when the pump 24 applies negative pressure to the spin chuck 21 with the substrate S placed on the upper surface of the spin chuck 21 in a substantially horizontal position, the spin chuck 21 sucks and holds the substrate S from below. On the other hand, when the pump 24 applies positive pressure to the spin chuck 21, the substrate S can be removed from the upper surface of the spin chuck 21. When the suction of the pump 24 is stopped, the substrate S can be moved horizontally on the upper surface of the spin chuck 21.

[0021] As shown in Fig. 3, the splash prevention mechanism 3 has a generally cylindrical cup 31 provided to surround the outer periphery of the substrate S held by the spin chuck 21, and a liquid receiving portion 32 provided below the outer periphery of the cup 31. The cup 31 is raised and lowered by the operation of a guard driving portion 33 (Fig. 5) in response to a control command from the control unit 9. When the cup 31 is positioned at the lower position, the upper end of the cup 31 is located below the peripheral portion Ss of the substrate S held by the spin chuck 21, as shown in Fig. 2. Conversely, when the cup 31 is positioned at the upper position, the upper end of the cup 31 is located above the peripheral portion Ss of the substrate S.

[0022] 2, when the cup 31 is in the lower position, the substrate S held by the spin chuck 21 is exposed to the outside of the cup 31. This prevents the cup 31 from becoming an obstacle, for example, when the substrate S is loaded onto or unloaded from the spin chuck 21.

[0023] On the other hand, when the cup 31 is in the upper position, the inner peripheral surface of the cup 31 surrounds the outer periphery of the substrate S held by the spin chuck 21. This makes it possible to prevent droplets of the processing liquid shaken off from the peripheral portion Ss of the substrate S from scattering inside the processing chamber 100 during the bevel etching process described below. It also makes it possible to reliably recover the processing liquid. That is, as the substrate S rotates, droplets of the processing liquid shaken off from the peripheral portion Ss of the substrate S adhere to the inner peripheral surface of the cup 31 and flow downward, and are collected and recovered by the liquid receiving portion 32 arranged below the cup 31.

[0024] The processing mechanism 4 has a base 41, a rotating support shaft 42, an arm 43, and a processing liquid nozzle 44. The base 41 is fixed to the processing chamber 100. The rotating support shaft 42 is provided rotatably relative to the base 41. The arm 43 extends horizontally from the rotating support shaft 42, and a processing liquid nozzle 44 is attached to its tip. The rotating support shaft 42 rotates in response to a control command from the control unit 9, causing the arm 43 to swing, and the processing liquid nozzle 44 at the tip of the arm 43 moves between a retracted position retracted from above the substrate S to the side and a processing position above the peripheral portion of the substrate S. In FIG. 3, the nozzle 44 indicated by the two-dot chain line is in the retracted position, and the nozzle 44 indicated by the solid line is in the processing position.

[0025] The processing liquid nozzle 44 is connected to a processing liquid supply unit 45 (FIG. 5). When the processing liquid supply unit 45 supplies the processing liquid toward the processing liquid nozzle 44 in response to a supply command from the control unit 9, the processing liquid is discharged from the processing liquid nozzle 44 toward a processing start position Ps. This processing start position Ps is a point on the path along which the peripheral portion Ss of the substrate S moves. Therefore, as the processing liquid nozzle 44 discharges the processing liquid while the spin chuck 21 rotates, each portion of the peripheral portion Ss of the substrate S is supplied with the processing liquid while passing through the processing start position Ps. As a result, a bevel etching process using the processing liquid is performed on the entire peripheral portion Ss of the substrate S.

[0026] The peripheral heating mechanism 5 includes an annular heater 51. The heater 51 incorporates a heating element that extends in the peripheral direction of the substrate S along the peripheral portion of the lower surface of the substrate S. When a heating command is given to the heater 51 from the control unit 9, the peripheral portion Ss of the substrate S is heated from below by heat emitted from the heating element. This raises the temperature of the peripheral portion Ss to a value suitable for the bevel etching process.

[0027] The imaging mechanism 6 includes a base 6A, a pivot 6B, an arm 6C, a head driver 6D, an illumination optical system 6E, an observation optical system 6F, and a head 6G. The base 6A is fixed to the processing chamber 100. The pivot 6B is rotatably provided on the base 6A. An arm 6C extends horizontally from the pivot 6B, and a head 6G is attached to its tip. When a control command is given from the control unit 9 to the head driver 6D (FIG. 5) that drives the arm 6C, the head driver 6D swings the arm 6C as shown by the dashed line in FIG. 3 in response to the command. As a result, the head 6G attached to the tip of the arm 6C reciprocates between a retreat position P1 where the head 6G retreats from above the substrate S to the side, and an imaging position P2 where the head 6G captures an image of the peripheral portion Ss of the substrate S. 3, the head unit 6G indicated by a solid line is in the retracted position, and the head unit 6G indicated by a dashed line is in the imaging position. At the imaging position P2, the head unit 6G is disposed close to the (-Y) side end of the substrate S.

[0028] As shown in FIG. 3, the illumination optical system 6E and the observation optical system 6F are provided at a position P3 spaced from the imaging position P2 in the X direction. This position P3 is spaced from each unit (the rotation mechanism 2, the scattering prevention mechanism 3, the processing mechanism 4, and the peripheral heating mechanism 5) that performs the bevel etching process on the substrate S and the cup 31. The illumination optical system 6E irradiates the illumination light L1 from the outside of the cup 31 toward the imaging position P2. At this time, the cup 31 is positioned at a lower position, and the head unit 6G is positioned at the imaging position P2, so that the illumination light L1 is incident on the head unit 6G. The illumination light L1 is diffusely reflected by the head unit 6G. The diffused light thus generated illuminates the peripheral portion Ss of the substrate S. Then, the reflected light L2 reflected by the peripheral portion Ss of the substrate S is further reflected by the head unit 6G. The reflected light L2 is guided from the head unit 6G toward the position P3 and incident on the observation optical system 6F. As a result, the observation optical system 6F acquires an image of the peripheral portion Ss of the substrate S, and sends the image data to the control unit 9.

[0029] Here, the peripheral portion Ss of the substrate S to be imaged in this embodiment will be described with reference to Fig. 4. As shown in Fig. 4, some substrates S, such as semiconductor wafers, have a bevel portion having an inclined surface formed on their peripheral portion. The "bevel portion" here refers to the entire area of ​​the peripheral portion Ss of the substrate S, whose surface is inclined with respect to the horizontal plane when the substrate S is in a horizontal position.

[0030] The cross-sectional shape and dimensions of the bevel are specified as standard specifications, with the maximum dimension Dmax shown by the dotted line and the minimum dimension Dmin shown by the dashed line, and generally a relatively high degree of freedom is given as long as they fall within these limits. In many cases, the cross section of the bevel is made up of multiple surfaces with different inclinations, as shown in Figure 4, but there are also cases where it is made up of a curved surface.

[0031] In the following, where necessary, the portion of the peripheral portion Ss of the substrate S that is flush with the upper surface of the substrate S will be referred to as the "A surface" and given the symbol Sa, and the edge surface of the substrate S will be referred to as the "C surface" and given the symbol Sc. The inclined surface connecting the A surface Sa and the C surface Sc will be referred to as the "B surface" and given the symbol Sb. The portion that is flush with the lower surface of the substrate S will be referred to as the "E surface" and given the symbol Se, and the inclined surface connecting the C surface Sc and the E surface Se will be referred to as the "D surface" and given the symbol Sd. In this specification, the "periphery portion Ss" is a concept that comprehensively includes each of these surfaces.

[0032] As described above, the head unit 6G has both a diffusion illumination function of receiving illumination light L1 from the illumination optical system 6E to generate diffuse light and illuminating the peripheral portion Ss of the substrate S with the diffuse light, and a guide function of guiding reflected light L2 reflected by the peripheral portion Ss to the observation optical system 6F. The configuration and operation of the head unit 6G will be described below with reference to Figures 6 to 9. After that, the configuration and operation of the illumination optical system 6E will be described in detail.

[0033] Fig. 6 is a perspective view showing the head part of the imaging mechanism. More specifically, Fig. 6(a) is a diagram showing a state where the head part 6G is placed at the imaging position P2, and Fig. 6(b) shows a state where the substrate S is removed from the head part 6G. The head part 6G has a diffuse illumination part 61 having a diffuse surface 610, a guide part 62 composed of three mirror members 62a to 62c each surrounded by the diffuse surface 610, and a holding part 63 that holds the diffuse illumination part 61. In Fig. 6, a dot is added to the area corresponding to the holding part 63 to distinguish it from the diffuse illumination part 61.

[0034] The diffuse illumination unit 61 is made of a white fluorine-based resin, for example, PTFE (polytetrafluoroethylene). More specifically, the diffuse illumination unit 61 is manufactured from a porous resin formed by sintering granular PTFE. For example, Spectralon manufactured by Labsphere can be used as such a resin material, and in this embodiment, the diffuse illumination unit 61 is finished into a shape suitable for substrate observation by processing it as follows. That is, the diffuse illumination unit 61 has a plate shape approximately parallel to the YZ plane, and a notch 611 is formed at the end on the (+Y) direction side. This notch 611 has a shape obtained by rotating a U-shape 90° clockwise when viewed from the (+X) direction side. By using the diffuse illumination unit 61 configured in this manner, a regular reflection suppression effect is achieved. This point will be described in detail later.

[0035] In the diffuse illumination section 61, an inclined surface 610 is provided along the cutout portion 611. The inclined surface 610 is provided so as to surround the cutout portion 611 from the top and bottom directions and the (-Y) direction, and is a tapered surface that is finished so as to incline in the (-X) direction as it approaches the cutout portion 611. The surface is finished so as to diffusely reflect incident light, and as will be described later, functions as a diffusion surface 610 that diffusely reflects the illumination light and causes it to be incident on the peripheral portion Ss of the substrate S.

[0036] Mirror members 62a to 62c are attached so as to be surrounded by diffusion surface 610. More specifically, a first mirror member 62a is attached to a position on diffusion surface 610 vertically above notch 611, a second mirror member 62b is attached to the (-Y) side of notch 611, and a third mirror member 62c is attached to a position vertically below notch 611. In this embodiment, mirror members 62a to 62c are made of Si (silicon) in consideration of chemical resistance, heat resistance, and the like.

[0037] On the other hand, the holding unit 63 is made of a resin having high resistance to chemicals and heat, such as PEEK (polyetheretherketone), and is a plate-like member having an outer shape generally similar to that of the diffuse illumination unit 61. The holding unit 63 is connected to the rear surface of the diffuse illumination unit 61, that is, the (-X) side main surface, and functions as a backup member. The holding unit 63 is also connected to the arm 6C. Therefore, the oscillating motion of the arm 6C causes the diffuse illumination unit 61 and the holding unit 63 to move integrally between the retracted position P1 and the imaging position P2.

[0038] As shown in FIG. 6(a), when the head unit 6G is at the imaging position P2 and the substrate S is held by the spin chuck 21, the peripheral portion Ss of the substrate S is positioned between the notches 611. When the notches 611 are viewed from the (+X) side in the (-X) direction, the first mirror member 62a reflects the images of the portions of the substrate peripheral portion Ss that are visible when viewed from above, that is, the A-side Sa and the B-side Sb. Similarly, the second mirror member 62b reflects the images of the portions of the substrate peripheral portion Ss that are visible when viewed from the side, that is, the B-side Sb, the C-side Sc, and the D-side Sd. Moreover, the third mirror member 62c reflects the images of the portions of the substrate peripheral portion Ss that are visible when viewed from below, that is, the D-side Sd and the E-side Se.

[0039] As will be described in detail later, the observation optical system 6F captures images in an imaging field set to view all three mirror members 62a-62c from the (+X) side. As a result, the images of the substrate S reflected in each of the mirror members 62a-62c are captured in a single image. That is, the observation optical system 6F can capture images of the A-side Sa, B-side Sb, C-side Sc, D-side Sd, and E-side Se of the substrate Ss all in a single image. By capturing images multiple times as the substrate S rotates, images of multiple regions of the peripheral portion Ss at different positions along the circumferential direction can be obtained.

[0040] In the following description, capturing images of the A-surface Sa and B-surface Sb of the substrate S reflected in the first mirror member 62a is referred to as "top surface imaging." Capturing images of the B-surface Sb, C-surface Sc, and D-surface Sd of the substrate S reflected in the second mirror member 62b is referred to as "side surface imaging." Capturing images of the D-surface Sd and E-surface Se of the substrate S reflected in the third mirror member 62c is referred to as "bottom surface imaging."

[0041] FIG. 7 is a diagram showing a typical way in which light that contributes to the top surface imaging proceeds. More specifically, FIG. 7(a) is a perspective view showing the course of light that is incident on and reflected by the head unit 6G, and FIG. 7(b) is a cross-sectional view of the vertical cut surface thereof. As shown by solid arrows in FIG. 7(a) and FIG. 7(b), the illumination light L1a proceeding in the (-X) direction along the top surface side of the substrate S enters the diffusion surface 610 of the head unit 6G. The illumination light L1a enters the upper diffusion surface 61a located particularly above the cutout portion 611 of the diffusion surface 610, and is diffusely reflected with characteristics similar to Lambertian reflection. Then, the diffusely reflected light enters the top surface of the substrate S from various directions, thereby illuminating the substrate peripheral portion Ss. In this embodiment, the head unit 6G and the illumination optical system 6E are arranged so that the angle of incidence of the illumination light L1a on the upper diffusion surface 61a is 54°. This point is the same for the lower diffusion surface 61c and the side diffusion surface 61b, which will be described next in sequence.

[0042] As indicated by the dotted arrows, the light reflected by the substrate S can travel in various directions, but among these, the light L2a that is incident on the mirror member 62a and is reflected by the mirror member 62a and travels in the (+X) direction is incident on the observation optical system 6F arranged on the optical path. By receiving this light, "top surface imaging" is realized, which images the peripheral portion Ss of the substrate S as viewed from the top surface side.

[0043] 7(b), a phenomenon similar to that on the upper surface side occurs on the lower surface side of the substrate S. That is, the head unit 6G has a top-bottom symmetrical structure, and illumination light L1c traveling in the (-X) direction along the lower surface side of the substrate S is incident on the lower diffusion surface 61c located particularly below the cutout portion 611 of the diffusion surface 610, and is diffusely reflected thereon to illuminate the lower surface of the substrate S. At this time, reflected light L2c reflected by the substrate S and the mirror member 62c and traveling in the (+X) direction is received, thereby achieving "lower surface imaging" that images the peripheral portion Ss as viewed from the lower surface side of the substrate S.

[0044] FIG. 8 is a diagram showing a schematic diagram of the progression of light that contributes to side imaging. More specifically, FIG. 8(a) is a perspective view showing the path of light that is incident on and reflected by the head unit 6G, and FIG. 8(b) is a cross-sectional view of the horizontal cut surface thereof. As shown by the solid arrows in FIG. 8(a) and FIG. 8(b), the illumination light L1b traveling in the (-X) direction along the side of the substrate S is incident on the diffusion surface 610 of the head unit 6G, and is diffusely reflected by the lateral diffusion surface 61b located on the side of the cutout portion 611 in particular. This light is incident on the side of the substrate S from various directions, thereby illuminating the substrate peripheral portion Ss.

[0045] Among the light reflected from the substrate S indicated by the dotted arrow, light L2b reflected by the mirror member 62b and traveling in the (+X) direction is incident on the observation optical system 6F arranged on the optical path. This realizes "side surface imaging" for imaging the peripheral portion Ss of the substrate S as viewed from the side.

[0046] The observation optical system 6F has an observation lens system composed of an object-side telecentric lens and a CMOS camera. Therefore, only the reflected light L2 (L2a, L2b, L2c) parallel to the optical axis of the observation lens system among the above reflected light is incident on the sensor surface of the CMOS camera, and an image of the peripheral portion Ss of the substrate S and the adjacent area is formed on the sensor surface. In this way, the observation optical system 6F captures the peripheral portion Ss of the substrate S and the adjacent area, and obtains an image Im including, for example, an upper surface image area Ma, a side surface image area Mb, and a lower surface image area Mc as shown in FIG. Then, the observation optical system 6F transmits image data indicating the image to the control unit 9.

[0047] 9A and 9B are diagrams showing an image of the peripheral portion of the substrate captured by the imaging unit. Fig. 9A is a schematic diagram showing the head unit 6G and the substrate S viewed from the (+X) side in the (-X) direction, and the area FV surrounded by a dashed line represents the imaging field of view of the observation optical system 6F. In this way, the imaging field of view FV of the observation optical system 6F is set to include the mirror members 62a to 62c of the head unit 6G.

[0048] Fig. 9(b) shows a schematic diagram of images of the substrate S reflected on the mirror members 62a to 62c within the imaging field of view FV. As shown in Fig. 9(b), images of the A-side Sa and B-side Sb of the peripheral portion Ss of the substrate S are reflected on the first mirror member 62a. Images of the B-side Sb, C-side Sc, and D-side Sd of the peripheral portion Ss of the substrate S are reflected on the second mirror member 62b. Images of the D-side Sd and E-side Se of the peripheral portion Ss of the substrate S are reflected on the third mirror member 62c. The observation optical system 6F captures these images collectively to obtain one image.

[0049] Fig. 9(c) is a schematic diagram of an image actually obtained by imaging. In the imaging mechanism 6 configured as described above, the illumination light from the illumination optical system 6E is diffused by the diffusion surface 610 to illuminate the substrate S, and an image is captured by receiving a portion of the reflected light from the substrate S. For this reason, it cannot be said that either the illumination light amount or the received light amount is sufficient. In order to capture an image satisfactorily under such circumstances, it is necessary to increase the sensitivity of the camera, and as a result, the detailed structure of the head part 6G is hardly reflected in the image due to so-called overexposure.

[0050] Therefore, as shown in Figure 9 (c), the image Im actually obtained includes a dark region Md corresponding to the cutout portion 611 and including an image of the side of the substrate S that is reflected out of focus within it, a top image region Ma corresponding to the image of the peripheral portion Ss of the substrate S viewed from above, a side image region Mb corresponding to the image of the peripheral portion Ss of the substrate S viewed from the side, and a bottom image region Mc corresponding to the image of the peripheral portion Ss of the substrate S viewed from below.

[0051] By analyzing the image Im including these regions, it is possible to obtain information indicating the shape of the peripheral portion of the substrate S in the circumferential direction, the etching state, etc. From this information, it is possible to inspect the amount of eccentricity of the substrate S placed on the spin chuck 21 with respect to the rotation axis AX, the amount of warping of the substrate S, the bevel etching result (etching width), etc.

[0052] In the substrate processing apparatus 1 equipped with the imaging mechanism 6 configured as described above, the control unit 9 controls each part of the apparatus to execute (A) substrate inspection before bevel etching, (B) alignment, (C) bevel etching after alignment, and (D) substrate inspection after bevel etching. As shown in Fig. 5, the control unit 9 has a calculation processing unit 91 that performs various calculation processes, a storage unit 92 that stores basic programs and image data, and an input display unit 93 that displays various information and receives input from an operator.

[0053] In the control unit 9, a calculation processor (CPU) 91 as a main control unit performs calculation processing according to a procedure described in a program, thereby controlling each part of the substrate processing apparatus 1 as follows. That is, as shown in Fig. 5, the calculation processor 91 functions as a positioning control unit 911 that performs positioning of the head unit 6G, an entire peripheral image acquisition unit 912 that acquires an entire peripheral image, an eccentricity amount derivation unit 913 that derives an amount of eccentricity of the substrate S from the entire peripheral image before the bevel etching process, a warpage amount derivation unit 914 that derives an amount of warpage of the substrate S from the entire peripheral image before the bevel etching process, an etching width derivation unit 915 that derives an etching width from the entire peripheral image after the bevel etching process, and a residue analysis unit 916 that analyzes residues from a residue-enhanced image obtained by image processing the entire peripheral image.

[0054] 5 denotes an eccentricity correction mechanism that moves the substrate S by the amount of eccentricity described above to correct the eccentricity of the substrate S with respect to the rotation axis AX. Since a conventionally known eccentricity correction mechanism can be used, a detailed description of the structure of the eccentricity correction mechanism 7 will be omitted here.

[0055] The illumination optical system 6E of the imaging mechanism 6 irradiates an area FV (see FIG. 9(a)) including the diffusion surface 610 with the illumination light L1 as primary illumination light, thereby generating diffuse light that is diffusely reflected by the diffusion surface 610 as secondary illumination light. The substrate S is then illuminated by the diffuse light. The observation optical system 6F of the imaging mechanism 6 receives a portion of the reflected light from the substrate S to image the peripheral portion Ss of the substrate S. In this manner, the peripheral portion Ss is observed by the observation optical system 6F. In this manner, the peripheral portion Ss of the substrate S is observed using the imaging mechanism 6, and the substrate S and the peripheral portion Ss respectively correspond to examples of the "object under observation" and the "portion under observation" of the present invention, and the imaging mechanism 6 functions as the "observation device" of the present invention.

[0056] Here, in order to obtain a better image of the peripheral portion Ss by the imaging mechanism 6, it is important to suppress the brightness of the specular reflection light contained in the secondary illumination light, that is, to exert the specular reflection suppression effect. The reason for this will be described with reference to Figs. 10 and 11.

[0057] FIG. 10 is a diagram showing the generation of regular reflected light and diffused light when the primary illumination light is irradiated to the diffuse illumination unit, where FIG. 10(a) shows the generation of regular reflected light and diffused light in a conventional example in which the diffuse illumination unit 61 is made of a conventionally used diffuse reflection material (for example, PTFE with a uniform surface by cutting), and FIG. 10(b) shows the generation of regular reflected light and diffused light in this embodiment in which the diffuse illumination unit 61 is made of a diffuse reflection material (Spectralon). FIG. 11 is a diagram showing an example of an image obtained by imaging the peripheral portion of a substrate, where FIG. 11(a) shows the image in the conventional example, and FIG. 11(b) shows the image in this embodiment. In the conventional example, when light L1 generated by an optical element such as an LED (Light Emitting Diode) is irradiated to the diffuse illumination unit 61 as the primary illumination light, regular reflected light is generated on the surface (diffusion surface 610) of the diffuse illumination unit 61 and is surface scattered on the diffusion surface 610. In addition, the light that penetrates the inside of the diffuse illumination unit 61 is diffusely reflected by the PTFE that constitutes the diffuse illumination unit 61, and then exits as diffuse light from the diffusion surface 610. In this way, the secondary illumination light emitted from the surface of the diffuse illumination unit 61 includes a relatively high intensity regular reflection light (thick solid line in the figure) and a diffuse light close to Lambertian reflection (thin dotted line in the figure), as shown in FIG. 10(a). The secondary illumination light has an extremely strong illuminance distribution only in the direction of the regular reflection light. When the peripheral portion Ss of the substrate S is actually illuminated with the primary illumination light L1 and an image is taken, a side image region Mb in which the bright line BL is reflected is obtained, as shown in FIG. 11(a), for example. Then, the ray trace of only the principal ray was performed, and the result was that the position of the bright line BL in the side image region Mb coincided. In other words, it was confirmed that the presence of regular reflection light is the main cause of the bright line BL.

[0058] In contrast, in this embodiment, as described above, the diffusion surface 610 is finished relatively roughly so that the surface roughness is 2 μm or more and 10 μm or less. Therefore, the primary illumination light L1 incident on the diffusion surface 610 and the light scattered inside the diffusion illumination unit 61 are surface-scattered by the diffusion surface 610. The "surface roughness" here is defined as the arithmetic mean roughness (Ra).

[0059] The diffuse illumination unit 61 is made of a porous resin formed by sintering granular PTFE, and has a microstructure with voids inside. Therefore, the primary illumination light L1 that enters the inside of the diffuse illumination unit 61 through the diffusion surface 610 is scattered inside the diffuse illumination unit 61 and then exits from the diffusion surface 610.

[0060] Furthermore, in this embodiment, Spectralon is used as the diffuse illumination section 61, and therefore has a relatively high transmittance to the primary illumination light L1. Moreover, the diffuse illumination section 61 is a crystalline resin, and the illumination light L1 is scattered at the boundaries of the crystal structure.

[0061] Thus, in this embodiment, (a) surface scattering, (b) internal scattering due to the presence of voids, and (c) internal scattering due to the crystal structure all occur. Therefore, the diffusing surface 610 is a uniform diffuse reflecting surface having characteristics similar to Lambertian reflection, and as shown in FIG. 10(b), the brightness of the specular reflection light in the secondary illumination light emitted from the diffusing surface 610 is reduced (specular reflection suppression effect), while the brightness of the diffuse reflection light is increased. In other words, the secondary illumination light emitted from the diffusing surface 610 is diffuse reflection light close to Lambertian reflection. Therefore, the inclusion of the specular reflection light in the secondary illumination light is suppressed, and as shown in FIG. 11(b), the bright line BL can be suppressed from being included in the side image region Mb. As a result, the peripheral portion Ss of the substrate S can be observed with excellent quality while solving the above problems.

[0062] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the embodiment, the diffuse illumination unit 61 that generates all three types of scattering (a) to (c) is used, but the diffuse illumination unit 61 configured to generate at least one of these types of scattering may be used. More specifically, the diffuse illumination unit 61 may be configured as follows.

[0063] Polyoxymethylene (e.g., Delrin (trademark)) is a crystalline resin similar to Spectralon, and its powder may be sintered and molded. The diffuse illumination unit 61 thus manufactured has the same effect as that of one made of Spectralon.

[0064] Moreover, the diffuse illumination portion 61 may be manufactured by uniformly dispersing particles of barium sulfate, which functions as a scattering material, inside a resin material.

[0065] In the above embodiment, the diffuse illumination section 61 is made of a sintered powder of a resin material, but the diffuse illumination section 61 may be made by, for example, subjecting the surface of PTFE to a blasting treatment. In this case, the surface to which the blasting treatment has been applied corresponds to the diffusion surface 610 of the diffuse illumination section 61, and surface scattering occurs on the diffusion surface 610.

[0066] In the above embodiment, PTFE and polyoxymethylene are exemplified as the resin material. However, other resin materials, such as ultra-high molecular weight polyethylene (UHMW-PE), polyethylene (PE), polyvinyl chloride (PVC), etc., may be used. chloride) and polypropylene (PP).

[0067] In addition, the entire diffuse lighting section 61 is made of a resin material such as PTFE, but it may also be configured so that a base material such as a metal material or ceramic material is covered with a coating layer made of the above-mentioned resin material (including one that disperses scattering substances), and the surface of the coating layer functions as the diffuse surface 610.

[0068] In the embodiment, the lengths of the upper diffusion surface 61a, the lower diffusion surface 61c, and the mirror members 62a and 62c in the Y direction are set in accordance with the bevel etching width of the substrate S, but the length of each part may be changed according to the range to be observed by the imaging mechanism 6. Also, head parts 6G having different Y-direction lengths of the diffusion surface and the mirror member may be prepared in this manner, and the head part 6G may be selectively used according to the imaging target range. When head parts 6G having different Y-direction lengths of the diffusion surface are prepared, the diffusion surface of the head part 6G may be composed of a continuous curved surface. When head parts 6G having different Y-direction lengths of the diffusion surface are prepared, a part of the diffusion surface of the head part 6G may be composed of a flat surface.

[0069] In the above embodiment, the observation lens system of the observation optical system 6F is configured with an object-side telecentric lens, but the configuration of the observation lens system of the observation optical system 6F is not limited to this. The observation lens system of the observation optical system 6F may be configured with other lenses.

[0070] In addition, in the above embodiment, the reflected light L2 reflected at the peripheral portion Ss of the substrate S is received by the observation optical system 6F via the mirror members 62a to 62c, but the reflected light L2 may also be received by the observation optical system 6F.

[0071] The mirror members 62a to 62c are not limited to Si (silicon). That is, other materials may be used as long as they have chemical resistance to the processing liquid and heat resistance to the processing temperature. The mirror members 62a to 62c may be configured, for example, by depositing a metal material on the surface of a material having chemical resistance and heat resistance. Furthermore, when the mirror members 62a to 62c are used in an environment in which chemical resistance and heat resistance are not required, the constituent material is not limited. The mirror members 62a to 62c may be configured of a material that does not have chemical resistance and heat resistance. The mirror members 62a to 62c may be configured, for example, by depositing a metal material on the surface of a material that does not have chemical resistance and heat resistance.

[0072] In the above embodiment, the imaging mechanism 6 is fixed, whereas the peripheral portion is imaged by moving the substrate S, which is the object under observation, but the imaging mechanism 6 may be configured to move while the substrate S is fixed. Also, both the substrate S and the imaging mechanism 6 may be moved. That is, the peripheral portion of the object under observation may be imaged by the observation device while the object under observation (substrate S) is moved relative to the observation device (imaging mechanism 6).

[0073] Furthermore, in the above embodiment, the imaging mechanism 6 corresponding to the observation device according to the present invention is incorporated into the substrate processing apparatus 1 that performs bevel etching on the peripheral portion Ss of the substrate S, but the application of the observation device (imaging mechanism 6) is not limited to this. The present invention can also be applied to an observation device that images an observation portion of an object to be observed. The imaging mechanism 6 corresponding to the observation device according to the present invention can also be applied to a substrate processing apparatus that supplies a coating film remover to the peripheral portion of the substrate S on which a coating film has been formed, thereby removing the coating film from the peripheral portion of the substrate S. It can also be applied to an observation device that observes the surface of the substrate before performing an exposure process. [Industrial Applicability]

[0074] The present invention can be generally applied to an observation technique for observing an object to be observed, such as a semiconductor wafer, and to substrate processing apparatuses that utilize the observation technique. [Explanation of symbols]

[0075] 1...Substrate processing device 2. Rotation mechanism 4. Processing mechanism 6...Imaging mechanism (observation device) 6E…Illumination optical system 6F: Observation optical system 6G…Head section 61...Diffused lighting section 61a to 61c, 610... Diffusion surface (uniform diffuse reflection surface) L1,L1a~L1c…Primary illumination light L2,L2a~L2c…Reflected light P2: Imaging position S...Substrate Ss: (substrate) edge

Claims

1. An observation apparatus for observing an observation portion of an object to be observed, comprising: an illumination optical system that irradiates a vicinity of the observation area with primary illumination light; a head unit having a diffusion illumination unit that diffuses the primary illumination light near the observation area using an even-diffusion reflecting surface having characteristics similar to Lambertian reflection, and that irradiates and illuminates the observation area with the diffused light generated by the even-diffusion reflecting surface as secondary illumination light; an observation optical system that receives light reflected from the observation area illuminated by the secondary illumination light and observes the observation area; An observation device comprising:

2. The observation device according to claim 1, An observation device, wherein the entire diffuse illumination section is formed from resin or resin having a scattering material dispersed therein that scatters light incident thereon.

3. The observation device according to claim 1, The observation device, wherein the diffuse illumination section has a base material and a coating layer coated on the base material, at least a portion of the surface of which is finished into the uniform diffuse reflecting surface.

4. The observation device according to claim 3, An observation device, wherein the entire coating layer is formed from a resin or a resin having a scattering material dispersed therein that scatters incident light.

5. The observation device according to claim 2 or 4, The resin is polytetrafluoroethylene or polyoxymethylene.

6. The observation device according to claim 5, The resin is a porous resin formed by sintering granular polytetrafluoroethylene or granular polyoxymethylene.

7. The observation device according to claim 2 or 4, The scattering material is barium sulfate.

8. The observation device according to any one of claims 1 to 4, The uniform diffuse reflection surface has a surface roughness of 2 μm or more and 10 μm or less in arithmetic mean roughness (Ra).

9. a rotation mechanism that holds and rotates the substrate; a processing mechanism that supplies a processing liquid to a peripheral portion of the substrate rotated by the rotation mechanism to process the peripheral portion of the substrate; and an observation device for observing the peripheral portion before or after the peripheral portion is treated, The observation device is an illumination optical system that irradiates a vicinity of the peripheral portion with primary illumination light; a head unit having a diffusion illumination unit that diffuses the primary illumination light near the peripheral portion by an even-diffusion reflecting surface having characteristics similar to Lambertian reflection, and that illuminates the peripheral portion by irradiating the diffused light generated by the even-diffusion reflecting surface as secondary illumination light; an observation optical system that receives light reflected from the peripheral portion illuminated by the secondary illumination light and observes the peripheral portion; A substrate processing apparatus comprising:

Images