Substrate processing apparatus and substrate processing method

Abstract

To provide a substrate processing apparatus and a substrate processing method capable of removing even ultrafine particles from the surface of a substrate in a short time.SOLUTION: In the present invention, the light having the directivity in the wavelength range including the absorption spectrum of the foreign matter is made incident into the substrate. The light travels while being totally reflected inside the substrate, and evanescent light leaks to the outside of the surface of the substrate when the light is totally reflected on the surface of the substrate or in the vicinity of the surface. The foreign matter absorbs the evanescent light and is evaporated and removed from the surface of the substrate.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a substrate processing apparatus and a substrate processing method for removing foreign matter adhering to a surface of a substrate and cleaning the surface. [Background technology]

[0002] In the manufacturing process of electronic devices such as semiconductor devices and liquid crystal display devices, a technique has been proposed for removing and cleaning fine particles adhering to the surface of bulk substrates such as silicon wafers and GaAs wafers, and thin-film-formed substrates in which a thin film is formed on a bulk substrate (hereinafter referred to as "substrate") (for example, Non-Patent Document 1). Non-Patent Document 1 describes a picosecond pulse laser cleaning technique that removes CuO particles adhering to the surface of a silicon wafer by scanning the surface with a picosecond pulse laser. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Lifang Mei et al., "Numerical analysis and experimental research on the removal of CuO particles from monocrystalline silicon surfaces by picosecond lase," Materials Science in Semiconductor Processing Volume 171, 1 March 2024, 107994, [Retrieved June 11, 2024], Internet<URL:https: / / www.sciencedirect.com / science / article / abs / pii / S136980012300687X> Summary of the Invention [Problem to be solved by the invention]

[0004] According to the above-mentioned conventional technology, it is possible to remove microparticles on the scale of μm, but it is impossible to remove particles on the scale of several hundred nanometers or less. Spot diameter: 80 μm Spot overlap rate: 25% Irradiation frequency: 500kHz When a picosecond pulse laser having the above formula is scanned over the entire surface of a 300 mm wafer to perform wafer cleaning, the processing time required for cleaning the entire surface is at least about 50 seconds.

[0005] SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a substrate processing apparatus and a substrate processing method that can remove even ultrafine particles from the surface of a substrate in a short time. [Means for solving the problem]

[0006] A first aspect of the present invention is a substrate processing apparatus for removing foreign matter adhering to the surface of a substrate, comprising: a substrate holding unit for holding a substrate; and a light irradiation unit that emits light having directionality in a wavelength range that includes the absorption spectrum of the foreign matter, and irradiates the light so that the angle of incidence of the light at an incident region where the light is incident on the substrate held by the substrate holding unit is smaller than the total reflection angle, and the light that enters the substrate through the incident region is totally reflected inside the substrate at an angle equal to or greater than the total reflection angle with respect to a direction perpendicular to the surface of the substrate, and is characterized in that the light is totally reflected at or near the surface of the substrate, thereby evaporating and removing foreign matter that has absorbed evanescent light that seeps out of the surface of the substrate.

[0007] A second aspect of the present invention is a substrate processing method comprising: a first step of holding a substrate having foreign matter adhering to its surface in a substrate holding section; a second step of irradiating the substrate held in the substrate holding section with directional light in a wavelength range that includes the absorption spectrum of the foreign matter; and a third step of removing the foreign matter using the light irradiated onto the substrate, wherein in the second step, the angle of incidence of the light with respect to an incident area through which the light is incident on the substrate is smaller than the total reflection angle, and the light incident on the substrate through the incident area is totally reflected inside the substrate at an angle equal to or greater than the total reflection angle with respect to a direction perpendicular to the surface of the substrate; and in the third step, the light is totally reflected at or near the surface of the substrate, and the evanescent light that seeps out outside the surface of the substrate is absorbed by the foreign matter, causing it to evaporate and be removed.

[0008] In the invention configured as described above, directional light in a wavelength range that includes the absorption spectrum of the foreign matter is incident on the inside of the substrate. This light travels through the inside of the substrate while being totally reflected, and evanescent light seeps out from the surface of the substrate when the light is totally reflected on or near the surface of the substrate. The evanescent light is absorbed by the foreign matter and is evaporated and removed from the surface of the substrate. [Effects of the Invention]

[0009] As described above, according to the present invention, even ultrafine particles can be removed from the surface of a substrate in a short time. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a plan view showing a schematic configuration of a substrate processing system equipped with an embodiment of a substrate processing apparatus according to the present invention. [Figure 2A] 1 is a diagram showing a configuration of a main part of a first embodiment of a substrate processing apparatus according to the present invention. [Figure 2B] FIG. 2B is a plan view of the center of FIG. 2A seen from above. [Figure 3] 3A and 3B are diagrams schematically illustrating the configuration and operation of a light irradiation unit. [Figure 4] 10A and 10B are diagrams schematically showing the configuration and operation of a light irradiation unit in a second embodiment of the substrate processing apparatus according to the present invention. [Figure 5] 10A and 10B are diagrams schematically showing the configuration and operation of a light irradiation unit in a third embodiment of a substrate processing apparatus according to the present invention. [Figure 6] 10A and 10B are diagrams schematically showing the configuration and operation of a light irradiation unit in a fourth embodiment of a substrate processing apparatus according to the present invention. [Figure 7] 10A and 10B are diagrams schematically showing the configuration and operation of a light irradiation unit in a fifth embodiment of the substrate processing apparatus according to the present invention. [Figure 8] 13A and 13B are views schematically showing the configuration and operation of a light irradiation unit in a sixth embodiment of the substrate processing apparatus according to the present invention. [Figure 9] FIG. 13 is a view schematically showing the configuration of a light irradiation unit in a seventh embodiment of the substrate processing apparatus according to the present invention. [Figure 10] FIG. 13 is a diagram showing a configuration of a main part of an eighth embodiment of a substrate processing apparatus according to the present invention. [Figure 11] 13A and 13B are views schematically showing the configuration and operation of a light irradiation unit in a ninth embodiment of the substrate processing apparatus according to the present invention. [Figure 12A] FIG. 23 is a diagram showing a configuration of a main part of a tenth embodiment of a substrate processing apparatus according to the present invention. [Figure 12B] 12B is an exploded perspective view showing a structure for suction-holding a substrate in the substrate processing apparatus shown in FIG. 12A. FIG. [Figure 13] 19A and 19B are views schematically showing the configuration and operation of a light irradiation unit in an eleventh embodiment of the substrate processing apparatus according to the present invention. [Figure 14] FIG. 2 is a diagram illustrating a portion of the substrate processing system shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1 is a plan view showing the schematic configuration of a substrate processing system equipped with one embodiment of a substrate processing apparatus according to the present invention. This is not a view showing the external appearance of the substrate processing system 100, but rather a schematic view showing the internal structure of the substrate processing system 100 by excluding the outer wall panels and other components. The substrate processing system 100 is a single-wafer processing apparatus that is installed, for example, in a clean room and processes substrates S one by one.

[0012] The substrate processing system 100 includes a plurality of processing units (substrate processing apparatuses) 1, each of which mainly processes a substrate S. In FIG. 1, four processing units 1 are arranged horizontally. The processing units 1 are also stacked vertically in multiple tiers. For example, when the processing units 1 are stacked and arranged in six tiers, the substrate processing system 100 includes a total of 24 processing units 1.

[0013] Each of the plurality of processing units 1 provided in the substrate processing system 100 receives a substrate S and cleans the substrate S by removing foreign matter adhering to the surface of the substrate S. In other words, the processing unit 1 corresponds to an example of a substrate processing apparatus 10 capable of performing an embodiment of a substrate processing method according to the present invention.

[0014] Here, the "substrate" in this embodiment can be any of various substrates, such as a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, etc. The following description will be given with reference to the drawings, taking as an example a substrate processing apparatus 10 used primarily for processing semiconductor wafers, but the apparatus can also be applied to processing the various substrates exemplified above.

[0015] As shown in FIG. 1, the substrate processing system 100 has a substrate processing area 110 where substrates S are processed. An indexer unit 120 is provided adjacent to the substrate processing area 110. The indexer unit 120 accommodates a container C for accommodating the substrates S (such as a FOUP (Front Opening Unified Pod) that accommodates multiple substrates S in a sealed state, an SMIF (Standard Insulated Fibre Channel), or the like). The indexer unit 120 has a container holder 121 that can hold a plurality of substrates S (e.g., pods with a Mechanical Interface, OCs (Open Cassettes)), etc. The indexer unit 120 also has an indexer robot 122 that accesses the containers C held by the container holder 121 and removes unprocessed substrates S from the containers C or stores processed substrates S in the containers C. Each container C contains a plurality of substrates S in a substantially horizontal position.

[0016] The indexer robot 122 comprises a base 122a fixed to the apparatus housing, an articulated arm 122b rotatable about a vertical axis relative to the base 122a, and a hand 122c attached to the tip of the articulated arm 122b. The hand 122c 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 a detailed description thereof will be omitted.

[0017] In the substrate processing area 110, a mounting table 112 is provided so that a substrate S from an indexer robot 122 can be placed thereon. In addition, a substrate transfer robot 111 is disposed approximately in the center of the substrate processing area 110 in a plan view. Furthermore, a plurality of processing units 1 (substrate processing apparatuses 10) are disposed so as to surround the substrate transfer robot 111. Specifically, the plurality of processing units 1 are disposed facing the space in which the substrate transfer robot 111 is disposed. The substrate transfer robot 111 randomly accesses the mounting tables 112 for these processing units 1 and transfers the substrate S between them. In this embodiment, these processing units 1 (substrate processing apparatuses 10) have the same function. Therefore, parallel processing of a plurality of substrates S is possible. Note that the mounting tables 112 are not necessarily required if the substrate transfer robot 111 can directly transfer the substrate S from the indexer robot 122 to the substrate transfer robot 111.

[0018] FIG. 2A shows the configuration of the main components of a substrate processing apparatus according to the present invention. FIG. 2B is a plan view of the center of FIG. 2A as viewed from above. In FIGS. 2A and 2B and the drawings described below, the dimensions and numbers of components are exaggerated or simplified for ease of understanding. The substrate processing apparatus 10 is a single-wafer processing apparatus that processes disk-shaped substrates S, such as semiconductor wafers, one by one. The substrate processing apparatus 10 includes a box-shaped chamber 11 having an internal space, a spin chuck 20 that holds a single substrate S horizontally within the chamber 11 and rotates it about a vertical rotation axis A1 passing through the center SC of the substrate S, a cylindrical guard unit 30 that receives gaseous foreign matter discharged outward from the spin chuck 20, and a light irradiation unit 40 that irradiates the substrate S held by the spin chuck 20 with laser light.

[0019] A loading / unloading port 14 through which the substrate S passes is provided on a side wall 11a of the chamber 11. A shutter 15 for opening and closing the loading / unloading port 14 is also attached to the side wall 11a.

[0020] The spin chuck 20 has a disk-shaped spin base 21 whose outer diameter is smaller than that of the substrate S, and a suction pump 22. The spin base 21 and the suction pump 22 are connected by a suction pipe 23 (shown by a broken line). A suction valve 24 is inserted in the suction pipe 23. Therefore, the suction pump 22 operates in response to a command from a control unit 90 that controls the entire apparatus, and the suction valve 24 opens in response to a command from the control unit 90, thereby transmitting the suction force of the suction pump 22 to the spin base 21. As a result, the back surface Sb of the substrate S on the spin base 21 is attracted to the spin base 21. In this way, the substrate S is held horizontally relative to the spin base 21. In this way, the spin chuck 20 corresponds to an example of a "substrate holding unit" of the present invention.

[0021] In this embodiment, as will be described later, foreign matter is removed by evanescent light generated at the position of total reflection when laser light is totally reflected inside the substrate S. Therefore, not only is the incident angle of the laser light adjusted so that the conditions for total reflection are met at the boundaries between the front and rear surfaces of the substrate S and the air layer, but the spin base 21 is also made of a low refractive index material so that the conditions for total reflection are met at the boundary between the substrate S and the spin base 21. In other words, by using a vacuum chuck made of a low refractive index material as the spin chuck 20, the laser light is totally reflected inside the substrate S over the entire surface of the substrate (excluding the peripheral edge).

[0022] The spin chuck 20 has a spin shaft 25 extending downward from the center of the spin base 21, a spin motor (rotating unit) 26 that rotates the spin shaft 25 and the spin base 21 about a rotation axis A1, and a motor housing 27 that houses the spin motor 26. Therefore, when the spin motor 26 is activated in response to a command from the control unit 90, the substrate S, which is sucked and held in a horizontal position on the spin base 21, rotates integrally with the spin base 21 about the rotation axis A1.

[0023] A guard section 30 is provided to surround the rotating substrate S. The guard section 30 has a cylindrical guard 31 that catches gaseous foreign matter components that are carried away by air currents generated as the substrate S rotates and are discharged outward from the substrate S, a cup 32 that catches foreign matter components guided downward by the guard 31, and an outer peripheral ring 33 that surrounds the guard 31 and the cup 32.

[0024] The guard 31 is movable vertically relative to the bottom of the chamber 11. Meanwhile, the cup 32 is fixed to the bottom of the chamber 11. As shown in FIG. 2A, a guard lifting unit 34 is connected to the guard 31. The guard lifting unit 34 vertically lifts and lowers the guard 31 between an upper position (position indicated by a two-dot chain line) and a lower position (position indicated by a solid line) in response to a command from the control unit 90, and stops the guard 31 at any position between the upper and lower positions. Here, at the upper position, the upper end of the guard 31 is located above the support position where the substrate S held by the spin chuck 20 is placed. At the lower position, the upper end of the guard 31 is located below the support position.

[0025] In order to remove foreign matter (PT in FIG. 3) adhering to the surface of the substrate S, the light irradiation unit 40 irradiates the substrate S held by the spin chuck 20 with light having a wavelength range (absorption wavelength band) and directionality that includes the absorption spectrum of the foreign matter, i.e., laser light. Here, the substrate S is a so-called bulk substrate composed only of a silicon wafer SW, and it is assumed that organic matter adhering to the surface of the substrate S is treated as foreign matter and that this organic matter is to be removed. The configuration and operation of the light irradiation unit 40 will be described below with reference to FIGS. 2A, 2B, and 3.

[0026] FIG. 3 is a diagram showing a schematic configuration and operation of the light irradiation unit. The light irradiation unit 40 includes a laser light source 41 that generates laser light in a wavelength range compatible with both the substrate S and the foreign matter PT. In this example, the substrate S is a silicon wafer SW, and the wavelength band transmitted through the silicon wafer SW is 1.2 μm to 6 μm. Also, the symbol PT in the figure represents organic foreign matter PT, and the absorption wavelength band of the organic C-H bonds contained in the foreign matter PT is around 3.4 μm. Therefore, in this embodiment, taking these points into consideration, an infrared laser is used as the laser light source 41.

[0027] The laser light source 41 is connected to the optical head 43 by an optical fiber 42. The optical head 43 is disposed with its emission surface 431 facing the peripheral edge Sbs of the back surface of the substrate S. More specifically, as shown in FIG. 2A , a base member 44 is attached to the upper surface of the motor housing 27. The optical head 43 extends upward from this base member 44, and its upper end is bent so as to face the peripheral edge Sbs of the back surface of the substrate S. The optical fiber 42 is connected to the lower end of the optical head 43. Therefore, when the laser light source 41 is turned on in response to a command from the control unit 90, the infrared laser L0 is transmitted to the optical head 43 via the optical fiber 42 and output obliquely upward from the emission surface 431 of the optical head 43.

[0028] As shown in FIG. 3 , the light irradiation unit 40 has a prism 45 disposed between the emission surface 431 and the rear surface peripheral portion Sbs of the substrate S. The prism 45 guides the infrared laser beam L0 to the rear surface peripheral portion Sbs and causes it to enter the substrate S. After the infrared laser beam L1 enters the substrate S, the prism 45 adjusts the path of the infrared laser beam L0 near the rear surface peripheral portion Sbs so that the infrared laser beam L1 travels through the substrate S while undergoing total internal reflection. In this embodiment, as shown in FIG. 3 , the prism 45 is manufactured by processing a rectangular parallelepiped block made of silicon extending in the radial direction D of the substrate S. More specifically, the cross section of the rectangular parallelepiped block is slightly wider than the beam diameter of the infrared laser beam L0, and the radially outer portion of the rectangular parallelepiped block is cut diagonally upward to the left, thereby forming an inclined surface 451. The prism 45 has a horizontal lower surface 452 and a horizontal upper surface 453 extending radially inward from the inclined surface 451. Furthermore, this prism 45 is held by a prism holding mechanism 46 (Figure 2A) in an orientation in which its horizontal upper surface 453 is spaced a certain distance d1 from the rear peripheral edge Sbs of the substrate S and the inclined surface 451 faces the exit surface 431 of the optical head 43.

[0029] As shown in FIG. 2A , the prism holding mechanism 46 includes two pillar-shaped members 461 extending upward from the base member 44 and spring members 462 attached to the tops of the pillar-shaped members 461. The horizontal lower surface 452 of the prism 45 is placed on the spring members 462, thereby stably holding the prism 45 without interfering with the rotating substrate S. The prism 45 functions to stably guide the infrared laser beam L0 into the substrate S while maintaining an angle θ equal to or greater than the total reflection angle θc relative to a direction Dv (indicated by the dashed line in the figure) perpendicular to both main surfaces (the front surface Sf and the back surface Sb) of the substrate S, which is an angle required for the infrared laser beam L0 to be totally reflected by the front surface Sf and the back surface Sb of the substrate S. Note that the external shape and type of the prism 45 are arbitrary as long as they can achieve this function; for example, a triangular prism may be used. These points are similar to those of other embodiments.

[0030] Furthermore, the distance d1 is set to be equal to or less than the diffraction limit of the infrared laser L0. For example, if the center wavelength λ of the infrared laser L0 and the angle θ are 3.4 μm and 60°, respectively, and the optical distance that can maintain the efficiency of capturing the infrared laser L0 in the gap between the prism 45 and the substrate S is λ / 8, the distance d1 is determined by the following inequality: d1<λ / 8×cosθ=212.5nm All you have to do is satisfy the above.

[0031] 3, an infrared laser beam L0 emitted from a laser light source 41 passes through an optical fiber 42, an optical head 43, a prism 45, and the rear surface peripheral portion Sbs of the substrate S in this order, and is irradiated as an infrared laser beam L1 onto the inside of the substrate S. In this manner, the region of the rear surface peripheral portion Sbs onto which the infrared laser beam L0 is incident corresponds to an example of the "incident region" of the present invention.

[0032] In this way, the infrared laser L1 incident on the interior of the substrate S is irradiated onto the surface Sf of the substrate S via the back surface Sb at the angle θ with respect to the direction Dv. The infrared laser L1 is totally reflected at this irradiation position Pf1 (the boundary position between the surface Sf of the substrate S and the air layer). Furthermore, because the refractive index of the air layer is lower than that of the substrate S, evanescent light Lef1 leaks from the surface Sf of the substrate S toward the air layer at the total reflection position. After the evanescent light Lef1 is generated once, the laser light L1a travels inside the substrate S toward the center SC of the substrate S (FIG. 2A) due to total reflection at the irradiation position Pf1, and is irradiated onto the back surface Sb of the substrate S at the angle θ. The infrared laser L1a is totally reflected at this irradiation position Pb1 (the boundary position between the back surface Sb of the substrate S and the air layer), and evanescent light Leb1 leaks from the back surface Sb of the substrate S toward the air layer. After the evanescent light Leb1 is generated once, the laser light L1b travels through the interior of the substrate S toward the center SC of the substrate S due to total reflection at the irradiation position Pb1, and is irradiated onto the surface Sf of the substrate S at the angle θ. This total reflection is repeated, and multiple evanescent lights Lef1, Lef2, ... are generated on the surface Sf of the substrate S. The spots of these evanescent lights Lef1, Lef2, ... are formed at a constant interval W in the radial direction D. Here, the relationship between the thickness t of the substrate S, the angle θ, and the spot interval W is given by W=2×t×tanθ For example, when t = 775 μm and θ = 60°, the spot interval W is 2.68 mm, and for a 300 mm wafer, approximately 110 evanescent light spots are formed on the surface Sf of the substrate S almost immediately after the laser light source 41 is turned on. For example, as shown in FIG. 3, if a foreign particle PT is attached to the surface Sf of the substrate S at the irradiation position Pf3, the foreign particle PT is heated by the evanescent light Lef3 and evaporated and removed as indicated by the dotted arrow in FIG. 3. Furthermore, the intensity of the evanescent light attenuates to 1 / e several hundred nanometers from the wafer surface, and exists as a local field enhanced to a maximum of approximately four times the intensity of the incident light. This so-called surface enhancement effect allows even nano-sized foreign particles PT to be efficiently heated and evaporated for cleaning. This also applies to the embodiments described later.

[0033] On the other hand, at the remaining irradiation positions Pf1, Pf2, Pf4, ..., Pb1, Pb2, ..., no foreign matter PT is attached, so there is almost no energy loss of the infrared laser during total reflection, and it is transmitted to the next irradiation position.

[0034] As described above, according to this embodiment, a single infrared laser beam L0 is used to form a large number of evanescent light spots, enabling foreign matter removal. Furthermore, the substrate S is rotated while 110 evanescent light spots are formed in a row in the radial direction D. This makes it possible to significantly increase the removal efficiency compared to conventional techniques that remove foreign matter by scanning a single laser beam.

[0035] Furthermore, the infrared laser traveling through the substrate S while undergoing total reflection is eventually emitted to the outside of the substrate S from a region on the opposite side of the center SC of the substrate S from the incident region. Therefore, as shown in Figures 2A and 2B, a beam stopper 47 is disposed opposite the emission region of the infrared laser. This beam stopper 47 is attached to the upper end of a support member 471 that stands upright above the top surface of the motor housing 27, and safely dissipates the infrared laser that has passed through the substrate S.

[0036] As described above, in the substrate processing apparatus 10 according to the first embodiment, the prism 45 corresponds to an example of the "first prism" of the present invention, and functions as the "prism portion" of the present invention. In this embodiment, an infrared laser is used to correspond to the fact that the foreign matter PT is organic matter, but if the composition of the foreign matter PT is different from that of organic matter, directional light having a wavelength range (absorption wavelength band) that includes the absorption spectrum of the foreign matter PT can be used.

[0037] Furthermore, if the laser light source 41 is configured to emit laser light with a pulse width of the order of picoseconds, the removal process is completed before the heat of the heated foreign matter PT reaches the substrate S. As a result, damage to the substrate S can be suppressed. Furthermore, if the laser light source 41 is configured to emit laser light with a pulse width of the order of femtoseconds, the foreign matter PT can be removed by physical impact rather than evaporation due to heat, and damage to the substrate S can be suppressed. These points also apply to the embodiments described later.

[0038] Furthermore, in this embodiment, the substrate S to be cleaned is a silicon wafer (bulk substrate), but the substrate processing apparatus 10 having the above configuration can also be used as is when the substrate S to be cleaned is a silicon wafer having a thin film formed thereon (second embodiment).

[0039] 4 is a diagram showing a schematic configuration and operation of a light irradiation unit in a second embodiment of a substrate processing apparatus according to the present invention. The second embodiment differs from the first embodiment in that it is configured to accommodate substrates S having different structures. Therefore, the same components are given the same reference numerals and descriptions thereof will be omitted.

[0040] In this second embodiment, as shown in FIG. 4, a substrate S having a film F1 (e.g., a silicon oxide film (refractive index = 1.4)) formed on a silicon wafer SW (refractive index = 3.44) is to be cleaned. In this case, the infrared laser L1 incident on the inside of the silicon wafer SW is irradiated toward the boundary between the silicon wafer SW and the film F1 at the angle θ with respect to the direction Dv. At this irradiation position Pf1, the infrared laser L1 is totally reflected, and evanescent light Lef1 seeps from the boundary toward the film F1. Meanwhile, the laser light L1a is totally reflected at the irradiation position Pf1 and travels inside the silicon wafer SW toward the center SC of the substrate S (FIG. 2A), and is irradiated onto the back surface Sb of the substrate S at the angle θ. At this irradiation position Pb1 (the boundary position between the back surface Sb of the substrate S and an air layer), the infrared laser L1a is totally reflected, and evanescent light Leb1 seeps from the back surface Sb of the substrate S. Furthermore, the laser light L1b travels inside the silicon wafer SW toward the center SC of the substrate S due to total reflection at the irradiation position Pb1, and is irradiated at the angle θ onto the boundary between the silicon wafer SW and the film F1. This total reflection is repeated, and multiple evanescent light beams Lef1, Lef2, ... are generated near the surface Sf of the substrate S. For example, as shown in Figure 4, if a foreign particle PT is attached to the surface Sf of the substrate S at a position directly above the irradiation position Pf3, the foreign particle PT will be heated by the evanescent light Lef3 via the film F1 and will be evaporated and removed as indicated by the dotted arrow in Figure 4.

[0041] The important thing to note here is the influence of the film F1. In other words, in order for total reflection to occur at the boundary between the silicon wafer SW and the film F1, when the refractive indices of the silicon wafer SW and the film F1 are n1 and n2, respectively, the following inequality must be satisfied: n2 <n1·sinθ Furthermore, the film thickness of the film F1 is z, and the light intensity I at a point a distance d above the boundary is calculated by the following formula:

[0042]

number

[0043] Therefore, when the film thickness z is thinner than the distance d, the decrease in light intensity is small, and the foreign particle PT can be removed without any problems, as shown in Figure 4. On the other hand, when the film thickness z is thicker than the distance d, the optical energy of the evanescent light does not propagate to the foreign particle PT, making removal of the foreign particle PT difficult. For example, as described above, if a silicon oxide film is formed as the film F1 on the silicon wafer SW, and the center wavelength λ of the infrared laser L0 and the angle θ are 3.4 μm and 60°, respectively, the distance d is 103 nm. When the thickness z of the film F1 is the same as the distance d, i.e., 103 nm, 36.8% of the optical energy of the evanescent light can be extracted to the surface of the film F1, contributing to the removal of the foreign particle PT.

[0044] 5 is a diagram showing a schematic configuration and operation of a light irradiation unit in a third embodiment of a substrate processing apparatus according to the present invention. The third embodiment differs from the second embodiment in that the first film F1 is configured to be compatible with substrates S having different thicknesses. Therefore, the same components are denoted by the same reference numerals and descriptions thereof will be omitted.

[0045] In the second embodiment, the infrared laser L1 irradiated onto the silicon wafer SW is totally reflected at the boundary between the silicon wafer SW and the film F1. In contrast, in the third embodiment, the following inequality (Refractive index n2 of film F1)>(Refractive index n1 of silicon wafer SW)×sinθ holds, as shown in Figure 5, a part of the infrared laser L1 passes through the boundary and proceeds to the film F1 according to Fresnel's law. If the emission angle θt of the infrared laser L3 at this boundary position Pi0 is adjusted, the infrared laser L3 irradiated to the film F1 is totally reflected at the boundary between the film F1 and the air layer, that is, at the surface Sf of the substrate S. For example, as shown in Figure 5, if the surface Sf of the substrate S is made up of a relatively thick film F1, and the refractive index of air is n3, the angle θ will be equal to the inequality sin -1 (n3 / n1)<θ <sin -1 (n2 / n1) By setting the angle θ so that the above relation is satisfied, the infrared laser L3 travels while undergoing total reflection inside the film F1. As in the third embodiment, a silicon oxide film (refractive index n2 = 1.4) is formed as the film F1 on the silicon wafer SW (refractive index n1 = 3.44). If the refractive index n3 of the air layer is 1, the angle θ can be set to exceed 16.9° and below 24.0°. With this setting, the infrared laser L3 that has passed through the boundary position Pi0 is irradiated onto the surface Sf (upper surface of the film F1) of the substrate S. At this irradiation position Pf1 (the boundary position between the surface Sf of the substrate S and the air layer), the infrared laser L3 is totally reflected, and evanescent light Lef1 seeps out from the surface Sf of the substrate S. After the evanescent light Lef1 is generated once, the laser light L3a travels inside the film F1 toward the center SC of the substrate S (FIG. 2A) due to total reflection at the irradiation position Pf1, and is irradiated onto the boundary between the silicon wafer SW and the film F1 at the above angle θt. At this irradiation position Pi1, the infrared laser L3a is totally reflected, and evanescent light Leb1 seeps out from the boundary. After the evanescent light Leb1 is generated once, the laser light L3b travels inside the substrate S toward the center SC of the substrate S due to total reflection at the irradiation position Pb1, and is irradiated onto the surface Sf of the substrate S at the angle θt. This total reflection is repeated, and multiple evanescent lights Lef1, Lef2, ... are generated on the surface Sf of the substrate S, as in the first embodiment. Spots of these evanescent lights Lef1, Lef2, ... are formed at regular intervals in the radial direction D. Then, for example, as shown in FIG. 5, if a foreign matter PT is attached to the surface Sf of the substrate S at the irradiation position Pf2, the foreign matter PT is heated by the evanescent light Lef2 and evaporated and removed, as indicated by the dotted arrow in FIG. 5.

[0046] As described above, in order to generate evanescent light by totally reflecting the infrared laser inside the substrate S, it is necessary to adjust the angle θ of the infrared laser L1 with high precision. To achieve this, it is desirable to provide an irradiation angle adjustment unit 48 that adjusts the angle that the light L1 incident on the substrate S through the incident region makes with the direction Dv perpendicular to the surface Sf of the substrate S. As the irradiation angle adjustment unit 48, a head attitude adjustment unit 48A shown in FIG. 6 or a refractive index adjustment unit 48B shown in FIG. 7 can be used.

[0047] 6 is a diagram schematically illustrating the configuration and operation of a light irradiation unit in a fourth embodiment of a substrate processing apparatus according to the present invention. As shown in the figure, a head attitude adjustment unit 48A is connected to the optical head 43, and adjusts the tilt of the optical head 43 in response to commands from a control unit 90 (fourth embodiment). In this way, in the fourth embodiment, the head attitude adjustment unit 48A controls the angle of the infrared laser L0 incident on the prism 45, thereby adjusting the angle θ that the infrared laser L1 makes with the direction Dv, and functions as the "irradiation angle adjustment unit" of the present invention.

[0048] FIG. 7 is a diagram schematically illustrating the configuration and operation of a light irradiation unit in a fifth embodiment of a substrate processing apparatus according to the present invention. As shown in the figure, a refractive index adjustment unit 48B is additionally provided in this fifth embodiment. The refractive index adjustment unit 48B supplies gas components other than air (such as carbon dioxide) to the gap between the prism 45 and the substrate S in response to a command from the control unit 90, filling the gap with the gas components. This changes the refractive index of the gap, making it possible to adjust the angle θ. The means for changing the refractive index of the gap is not limited to replacing the gas components, and may also be configured to change the temperature, air pressure, humidity, or the like. In this way, in the fifth embodiment, the refractive index adjustment unit 48B functions as the "irradiation angle adjustment unit" of the present invention.

[0049] FIG. 8 is a diagram schematically illustrating the configuration and operation of a light irradiation unit in a sixth embodiment of a substrate processing apparatus according to the present invention. This sixth embodiment differs significantly from the first embodiment in that the optical head 43 is provided so as to be movable in the radial direction D and that a head moving unit 49 is connected to the optical head 43. The head moving unit 49 moves the optical head 43 in the radial direction D in response to a command from the control unit 90. As the optical head 43 moves, the total reflection position also moves in the radial direction D. As shown in FIG. 8, the evanescent light beams Lef1, Lef1', and Lef1'' move in the radial direction D in this order relative to the surface Sf of the rotating substrate S, and the other evanescent light beams also move in the same manner. For example, by matching the movement range of the head moving unit 49 with the spot spacing W described above, it is possible to form evanescent light spots uniformly over the entire surface of the substrate S except for the peripheral surface portion Sfs. As a result, foreign matter PT can be reliably removed over a wide area, resulting in high cleaning efficiency. The technical matter of providing the head moving unit 49 in this way can be applied to the second to fifth embodiments as well as the embodiments described later, and by applying it additionally, cleaning efficiency can be improved.

[0050] Furthermore, instead of providing the head moving unit 49, a plurality of optical heads 43 may be arranged in the radial direction D, and the infrared laser L0 may be emitted from all of the optical heads 43. Furthermore, the infrared laser L0 may be emitted from the plurality of optical heads 43 in order.

[0051] In the sixth embodiment, the single optical head 43 is moved in the radial direction D to achieve multiple spots, but instead of providing the head moving unit 49, multiple optical heads 43 may be arranged in the radial direction D and the infrared laser L0 may be irradiated from all the optical heads 43. In addition, the infrared laser L0 may be irradiated from the multiple optical heads 43 in order.

[0052] Furthermore, multiple combinations of the optical head 43, the prism 45, and the beam stopper 47 may be provided. For example, as shown in FIG. 9, four combinations of the optical heads 43a to 43d, the prisms 45a to 45d, and the beam stoppers 47a to 47d may be combined, and arranged at equal angular intervals in a plan view from above (seventh embodiment). In addition, in this seventh embodiment, in each combination, the area where the infrared laser beam is incident on the back surface Sb of the substrate S via the prism 45 from the optical head 43, i.e., the incident area, is shifted from one another in the radial direction. This provides the following advantageous effects. Specifically, if the incident area is fixed to the peripheral edge of the back surface of the substrate S, the infrared laser beam is attenuated as it propagates, resulting in a biased distribution of optical energy in the radial direction. In contrast, by varying the incident areas from one another in the radial direction, the incident areas are located at multiple locations on the peripheral edge and central part of the back surface of the substrate S. This distributes the degree of attenuation of the infrared laser beam within the substrate S, thereby achieving uniform optical energy. As a result, the in-plane uniformity of the cleaning efficiency on the surface Sf of the substrate S can be improved.

[0053] In the substrate processing apparatus 10 configured in this manner, the prism 45a corresponds to an example of the "first prism" of the present invention, and the prisms 45b to 45d correspond to an example of the "second prism" of the present invention, and these prisms 45a to 45d function as the "prism portion" of the present invention.

[0054] 10 is a diagram showing the configuration of the main parts of an eighth embodiment of a substrate processing apparatus according to the present invention. The eighth embodiment differs significantly from the first embodiment (FIG. 2A) in that a rinse processing unit 50 that performs a rinse process on the surface Sf of the substrate S is added. The following description will focus on the differences, and the same components will be denoted by the same reference numerals and will not be described again.

[0055] The rinse processing unit 50 has a function of supplying a rinse liquid such as DIW (deionized water) to the surface Sf of the substrate S after the start of the evaporation removal process of the foreign particles PT using evanescent light. The rinse processing unit 50 has a rinse liquid nozzle 51 that discharges the rinse liquid downward toward the surface Sf of the substrate S. The rinse liquid nozzle 51 is connected to a rinse liquid pipe 52 that guides the rinse liquid. When a rinse liquid valve 53 inserted in the rinse liquid pipe 52 is opened in response to a command from the control unit 90, the rinse liquid is continuously discharged downward from the discharge port of the rinse liquid nozzle 51. In addition to the above-mentioned DIW, the rinse liquid may be any of IPA (isopropyl alcohol), electrolytic ionized water, hydrogen water, ozone water, and hydrochloric acid water with a diluted concentration (for example, about 10 to 100 ppm), or other liquids.

[0056] The rinse liquid nozzle 51 is a scan nozzle. The rinse liquid nozzle 51 is connected to a nozzle moving unit 54 that moves the rinse liquid nozzle 51 in at least one of the vertical and horizontal directions. The nozzle moving unit 54 moves the rinse liquid nozzle 51 horizontally between a processing position where the rinse liquid discharged from the rinse liquid nozzle 51 lands on the center of the surface of the rotating substrate S and a standby position where the rinse liquid nozzle 51 is positioned around the spin chuck 20 in a plan view.

[0057] In the eighth embodiment, the control unit 90 moves the rinse liquid nozzle 51 to a position above the center SC of the rotating substrate S, i.e., to the processing position. Once preparation for the rinsing process is completed, the control unit 90 emits an infrared laser to irradiate the substrate S. As a result, evanescent light Lef1, Lef2, ... is generated by total reflection of the infrared laser inside the substrate, and foreign particles PT adhering to the surface Sf of the substrate S are evaporated and removed (cleaning process). Immediately after starting this cleaning process, the control unit 90 opens the rinse liquid valve 53. This forms a rinse liquid flow that flows outside the substrate S, and the foreign particles PT evaporated and removed from the surface Sf of the substrate S by the evanescent light Lef1, Lef2, ... are washed away to the outside of the substrate S by the rinse liquid flow. The foreign particles PT and the rinse liquid are received by the guard unit 30. As a result, in addition to the same effects as in the first embodiment, another effect of effectively preventing the evaporated and removed foreign particles PT from re-adhering to the substrate S is obtained.

[0058] The rinse processing unit 50 can be applied to the second to seventh embodiments described above, as well as the ninth embodiment described next, and is effective in preventing the foreign matter PT that has been evaporated and removed from adhering again to the substrate S.

[0059] FIG. 11 is a diagram illustrating the configuration and operation of a light irradiation unit in a ninth embodiment of a substrate processing apparatus according to the present invention. This ninth embodiment differs significantly from the first embodiment in that an infrared laser L0 is directly irradiated onto the substrate S without using a prism. As shown in FIG. 11, some substrates S, such as semiconductor wafers, have a beveled portion BV formed on their peripheral edge. The term "beveled portion" here refers to the entire edge region of the substrate S, including the portion that is chamfered along the edge and has a finished inclined surface BV1 that is inclined at an angle θB with respect to the horizontal when the substrate S is in a horizontal position. In this specification, the angle θB is referred to as the "bevel cut angle θB."

[0060] In the first to eighth embodiments, it is impossible to configure the prism 45 so that the angle θ satisfies the total reflection condition while irradiating the infrared laser L0 directly onto the rear peripheral edge Sbs of the substrate S. On the other hand, as shown in FIG. 11, if the substrate S has a bevel portion BV, the infrared laser L0 from the optical head 43 may be irradiated onto the inside of the substrate S via an inclined surface BV1 (corresponding to an example of the "incident region" of the present invention). In this case, the angle of incidence of the infrared laser L0 onto the inclined surface BV1 is (θ-θB). Therefore, the condition for the infrared laser L0 to pass through the inclined surface BV1 and be irradiated onto the inside of the substrate S as the infrared laser L1 is satisfied by the following equation: |θ-θB|<θc=sin -1 (n2 / n1) where n1...refractive index of the substrate S, n2...refractive index of the air layer, θc...total reflection angle, The condition for the infrared laser L1 to be totally reflected at the irradiation position Pf1 of the infrared laser L1 is to satisfy the following formula: θ>θc=sin -1 (n2 / n1) Therefore, when θ≧θB, the following inequality is satisfied: sin -1 (n2 / n1)<θ <sin -1 (n2 / n1)+θB On the other hand, when θ<θB, the following two inequalities, θ>θB-sin -1 (n2 / n1) θ>sin -1 (n2 / n1) For example, if the substrate S (refractive index n1 = 3.44), the air layer (refractive index n2 = 1), and the bevel cut angle θB = 30°, the angle θ should be set within the angle range from 16.9° to 46.9°.

[0061] With this setting, the infrared laser L0 passes through the inclined surface BV1 and is irradiated into the interior of the substrate S as infrared laser light L1. Then, at irradiation position Pf1 (the boundary position between the surface Sf of the substrate S and the air layer), the infrared laser light L1 is totally reflected, and evanescent light Lef1 seeps from the surface Sf of the substrate S toward the air layer. After the evanescent light Lef1 is generated once, the laser light L1a travels inside the substrate S toward the center SC of the substrate S (FIG. 2A) due to total reflection at irradiation position Pf1, and is irradiated onto the back surface Sb of the substrate S at the angle θ. At this irradiation position Pb1 (the boundary position between the back surface Sb of the substrate S and the air layer), the infrared laser L1a is totally reflected, and evanescent light Leb1 seeps out from the back surface Sb of the substrate S. After the evanescent light Leb1 is generated once, the laser light L1b travels inside the substrate S toward the center SC of the substrate S due to total reflection at the irradiation position Pb1, and is irradiated onto the surface Sf of the substrate S at the angle θ. This total reflection is repeated, and a plurality of evanescent light beams Lef1, Lef2, ... are generated on the surface Sf of the substrate S. Therefore, the same effects as those of the first embodiment can be obtained.

[0062] Fig. 12A is a diagram showing the configuration of the main parts of a tenth embodiment of a substrate processing apparatus according to the present invention. Fig. 12B is an exploded perspective view showing the structure for suction-holding a substrate in the substrate processing apparatus shown in Fig. 12A. The tenth embodiment differs significantly from the first embodiment (Fig. 2A) in the shape of the prism and the structure for suction-holding the substrate S. The following description will focus on these differences, and the same components will be denoted by the same reference numerals and will not be described again.

[0063] In the tenth embodiment, the prism 450 is finished in a ring shape. More specifically, the prism 450 has a shape obtained by continuously rotating the longitudinal cross section of the prism 45 employed in the first embodiment around the rotation axis A1, i.e., a circular ring shape. As shown in FIG. 12B, the upper surface 455 of this ring-shaped prism 450 is a circular horizontal surface having an outer diameter equal to the diameter of the substrate S, and is capable of supporting the back surface Sb of the substrate S from below. In addition, the upper surface 455 is provided with a circular groove 456 that opens upward. Therefore, as shown in FIG. 12A, when the substrate S is placed on the upper surface 455 of the prism 450, the substrate S is supported by the prism 450 with the groove 456 closed.

[0064] The lower surface 457 of the prism 450 is a circular horizontal surface having an outer diameter smaller than the diameter of the substrate S and the same as that of the spin base 21, allowing it to be attached to the upper surface of the spin base 21. Although not shown in the drawings, four through-holes extend to the lower surface 457 in the bottom surface of the groove 456, forming suction paths connecting the upper surface 455 of the prism 450 to the lower surface 457. A total of four suction passages 211 are provided in the spin base 21 corresponding to the through-holes. The prism 450 is attached to the upper surface of the spin base 21 with the through-holes and the suction passages 211 aligned vertically. Each suction passage 211 communicates with the suction pipe 23. Therefore, the interior of the groove 456 is connected to the suction pump 22 via the through-holes, the suction passages 211, and the suction pipe 23. Therefore, after the substrate S is transferred onto the prism 450 by the substrate transport robot 111 and the opening of the groove portion 456 is blocked, the suction force of the suction pump 22 is applied to the groove portion 456 through the above-mentioned communication path, causing the substrate S to be adsorbed onto the prism 450 and become freely rotatable around the rotation axis A1 together with the prism 450 and the spin base 21.

[0065] As described above, in order to enable the substrate transfer robot 111 to smoothly place the substrate S on the prism 450, the lift pins 28 are provided so as to be able to move up and down relative to the spin base 21. That is, when receiving the substrate S, the lift pins 28 rise into the hollow portion 458 of the prism 450, as shown by the dotted lines in FIG. 12B, so that the substrate S can be received. Subsequently, as shown by the solid lines in FIG. 12B, the lift pins 28 descend below the upper surface of the spin base 21, so that the substrate S is supported by the prism 450 and can be held by suction with the suction force of the suction pump 22. Furthermore, when the spin motor 26 is operated with the spin base 21, prism 450, and substrate S integrated in this manner, the substrate S rotates about the rotation axis A1.

[0066] While the substrate S is rotating in this manner, the laser light source 41 emits an infrared laser beam L0, which is irradiated onto the substrate S via the inclined surface 459 of the prism 450. Then, as in the first embodiment, the infrared laser beam L1 that passes through the rear surface peripheral portion Sbs of the substrate S and travels inside the substrate S is totally reflected. The evanescent light spot generated at this time evaporates and removes the foreign matter PT. As a result, according to the tenth embodiment, the same effects as those of the first embodiment can be obtained.

[0067] As described above, in the tenth embodiment, the prism 450 corresponds to an example of the "fourth prism" of the present invention, and functions as the "prism portion" of the present invention.

[0068] In the above first to seventh embodiments, the prism 45 is arranged below the substrate S held by the spin chuck 20, but the prism 45 may be arranged above the substrate S, and the infrared laser L0 may be irradiated from the peripheral surface Sf of the substrate S (eleventh embodiment).

[0069] 13 is a diagram schematically illustrating the configuration and operation of a light irradiation unit in an eleventh embodiment of a substrate processing apparatus according to the present invention. The substrate processing apparatus 10 according to the eleventh embodiment is suitable for removing and cleaning foreign matter PT from the surface Sf of a substrate S having a multilayer film structure. Here, cleaning of a substrate S having two types of films, a first film F1 and a second film F2, stacked in this order on a silicon wafer SW as shown in FIG. 13 will be described, but the number of films is not limited to "2."

[0070] In the eleventh embodiment, a prism 45 is disposed at a distance d1 from the peripheral portion Sfs of the front surface of the substrate S. As in the first embodiment, an infrared laser L0 is irradiated onto the inclined surface 451 of the prism 45 from an optical head (not shown). This prism 45 has the function of making the infrared laser L0, which is guided to the peripheral portion of the uppermost film F2 through the prism 45, incident on the film F2, and making the infrared laser L0 incident on the uppermost second film F2 of the substrate S while ensuring an angle θ that is equal to or greater than the total reflection angle with respect to a direction Dv (the direction of the dashed line in the figure) perpendicular to both main surfaces (front surface Sf, back surface Sb) of the substrate S. That is, the condition for achieving the above function is to satisfy the following two inequalities, where n1, n2, and n3 are the refractive indices of the first film F1, the second film F2, and the air layer, respectively: (Angle of incidence θ to the boundary between films F1 and F2)>θc1=sin -1 (n1 / n2)

[0071] (Angle of incidence θ to the boundary between the film F1 and the air layer)>θc2=sin -1 (n3 / n2) For example, if the refractive index n3 of the air layer is "1" and the films F1 and F2 are made of silicon oxide (n1=1.4) and silicon nitride (n2=1.9), respectively, then θ>47.5° can be set to.

[0072] In the substrate processing apparatus 10 configured as described above, as shown in the figure, an infrared laser beam L1 incident on the peripheral edge of the film F2, i.e., the peripheral edge Sfs of the surface of the substrate S, travels toward the film F1 inside the film F2. The infrared laser beam L1 is then totally reflected at an irradiation position Pi1 on the film F1 (the boundary between the films F1 and F2), and evanescent light Lei1 seeps out. After the evanescent light Lei1 is generated once, the laser beam L1a travels inside the film F2 toward the center SC of the substrate S (FIG. 2A) due to total reflection at the irradiation position Pi1, and is irradiated onto the surface Sf of the substrate S (the upper surface of the film F2) at the angle θ. The infrared laser beam L1a is totally reflected at this irradiation position Pf1 (the boundary between the surface Sf of the substrate S and the air layer), and evanescent light Lef1 seeps out from the surface Sf of the substrate S. After the evanescent light Lef1 is generated once, the laser light L1b travels through the inside of the film F2 toward the center SC of the substrate S due to total reflection at the irradiation position Pf1, and is irradiated onto the film F1 at the angle θ. This total reflection is repeated, and multiple evanescent light beams Lef1, Lef2, ... are generated on the surface Sf of the substrate S. Therefore, the same effects as those of the first embodiment can be obtained.

[0073] As described above, in the eleventh embodiment, the prism 45 corresponds to an example of the "third prism" of the present invention, and functions as the "prism portion" of the present invention.

[0074] FIG. 14 is a diagram illustrating a portion of the substrate processing system illustrated in FIG. 1. In the substrate processing system 100, the processing unit 1 may be composed of a plurality of substrate processing apparatuses 10. For example, a cleaning processing tower in which a plurality of substrate processing apparatuses 10 are stacked may be arranged as the processing unit 1. In such a case, each substrate processing apparatus 10 may be equipped with a laser light source 41. Alternatively, each cleaning processing tower may be equipped with a laser light source 41. For example, as illustrated in FIG. 14, the processing unit 1 may be composed of substrate processing apparatuses 10A to 10C in which the laser light source 41 is removed from the substrate processing apparatus 10 according to the first embodiment, the laser light source 41, and a splitter 411. In the processing unit 1 illustrated in FIG. 14, an infrared laser L emitted from the laser light source 41 is split by the splitter 411 into a plurality (three in this embodiment) of infrared laser beams L0. The three split infrared laser beams L0 are propagated to the optical heads 43 of the substrate processing apparatuses 10A to 10C, respectively. By using such a splitting structure, the cost of each substrate processing apparatus and the overall cost of the substrate processing system can be reduced. The present invention is not limited to the above-described embodiment, and various modifications can be made to the above-described embodiment without departing from the spirit of the present invention. For example, in Fig. 14, the processing unit 1 is composed of three substrate processing apparatuses 10A to 10C, but the number and arrangement of the substrate processing apparatuses 10 are arbitrary.

[0075] Furthermore, in the above embodiment, an infrared laser is used as the "light having directionality in a wavelength range that includes the absorption spectrum of the foreign matter" of the present invention in response to the fact that the foreign matter PT is organic, but it is desirable to change the wavelength of the light, etc., depending on the composition of the foreign matter PT. [Industrial Applicability]

[0076] The present invention can be applied to the general substrate processing technology for removing foreign matter adhering to the surface of a substrate and cleaning the surface. [Explanation of symbols]

[0077] 10, 10A to 10C...Substrate processing equipment 20...Spin chuck (substrate holding part) 26...Spin motor (rotating part) 40...Light irradiation unit 41...Laser light source 45, 450...Prism 45a...First prism 45b~45d...Second prism 48…Irradiation angle adjustment section 48A...Head position adjustment unit (beam angle adjustment unit) 48B...Refractive index adjustment unit (beam angle adjustment unit) 49...Head moving part 50...Rinse processing section 51...Rinse liquid nozzle 54...Nozzle moving part 90...Control unit 100...Substrate processing system 211...Suction passage A1...Rotation axis BV: Bevel BV1...(Bevel) Inclined surface D...radial direction F1…first membrane F2…Second film L0, L1...Infrared laser Lef1,Lef1'',Lef1',Lef2,Lef3...Evanescent light PT…Foreign object S...Substrate SW: Silicon wafer Sb...(back surface of substrate S) Sf...surface (of substrate S) Sfs: Surface periphery Sbs: Back edge

Claims

1. A substrate processing apparatus for removing foreign matter adhering to a surface of a substrate, a substrate holder for holding the substrate; a light irradiation unit that emits light having directionality in a wavelength range that includes the absorption spectrum of the foreign matter, and irradiates the light so that an incident angle of the light on an incident area where the light is incident on the substrate held by the substrate holding unit is smaller than a total reflection angle, and the light that has entered the substrate through the incident area is totally reflected inside the substrate at an angle that is equal to or larger than the total reflection angle with respect to a direction perpendicular to the surface of the substrate, A substrate processing apparatus characterized in that the foreign matter that has absorbed evanescent light that seeps out to the outside of the surface of the substrate as a result of the light being totally reflected on or near the surface of the substrate is evaporated and removed.

2. The substrate processing apparatus according to claim 1 , The light irradiation unit includes a light source that generates the light, and a prism unit that guides the light from the light source to the incident area.

3. 3. The substrate processing apparatus according to claim 2, the incident region is a peripheral portion of the back surface of the substrate, The substrate processing apparatus, wherein the prism unit has a first prism provided below the rear surface peripheral portion and configured to guide the light from the rear surface side of the substrate to the rear surface peripheral portion.

4. 3. The substrate processing apparatus according to claim 2, the incident region is located at a plurality of locations including a peripheral portion of the rear surface of the substrate and an intermediate portion of the rear surface that is closer to the center of the substrate than the peripheral portion of the rear surface, The prism section includes a first prism provided below the rear surface peripheral portion and guiding the light from the light source to the rear surface peripheral portion of the substrate, and a second prism provided below the rear surface intermediate portion and guiding the light from the light source to the rear surface intermediate portion of the substrate.

5. The substrate processing apparatus according to claim 1 , the incidence area is a chamfered inclined surface along the edge of the substrate; the light irradiation unit has a light source that generates the light, and irradiates the light so that the angle of incidence of the light at an incident area where the light is incident on the substrate held by the substrate holding unit is smaller than the total reflection angle, and the light that is incident on the substrate through the incident area is totally reflected inside the substrate at an angle equal to or greater than the total reflection angle with respect to a direction perpendicular to the surface of the substrate.

6. 3. The substrate processing apparatus according to claim 2, the incident region is a peripheral portion of the surface of the substrate, The substrate processing apparatus, wherein the prism section has a third prism provided above the peripheral edge portion of the front surface and configured to guide the light from the front surface side of the substrate to the peripheral edge portion.

7. 7. The substrate processing apparatus according to claim 6, When the second-highest and highest-level films among the plurality of films stacked vertically within the substrate are defined as a first film and a second film, respectively, the light irradiation unit is configured such that an incident angle of the light to the incident region on the surface of the second film is smaller than a total reflection angle, and the light incident on the second film through the incident region is totally reflected by the front and rear surfaces of the second film at an angle equal to or larger than the total reflection angle with respect to a direction perpendicular to a boundary between the second film and the first film, The substrate processing apparatus evaporates and removes the foreign matter adhering to the second film that absorbs evanescent light seeping out of the surface of the second film due to total reflection of the light on the surface of the second film.

8. 8. The substrate processing apparatus according to claim 2, 3, 4, 6 or 7, The light irradiation unit includes an irradiation angle adjustment unit that adjusts the angle that the light incident on the substrate through the incident area makes with a direction perpendicular to the surface of the substrate.

9. 9. The substrate processing apparatus according to claim 8, The irradiation angle adjustment unit includes a head attitude adjustment unit that controls an incident angle of the light incident on the prism unit.

10. 9. The substrate processing apparatus according to claim 8, the prism portion is disposed at a distance from the rotating substrate, The irradiation angle adjustment unit has a refractive index adjustment unit that adjusts the angle of incidence of the light to the incident area by controlling the refractive index of a gap formed between the prism unit and the substrate.

11. 5. The substrate processing apparatus according to claim 2, a rotation unit that rotates the substrate holding unit, which holds the substrate in a horizontal position, about a rotation axis that passes through the center of the substrate, The substrate processing apparatus, wherein the prism unit is disposed at a distance from the rotating substrate.

12. The substrate processing apparatus according to claim 11, The substrate processing apparatus, wherein the prism unit is disposed so that the distance between the prism unit and the rotating substrate is equal to or less than the diffraction limit of light.

13. The substrate processing apparatus according to claim 11, a rinse processing unit that supplies a rinse liquid to a central portion of a surface of the rotating substrate to form a rinse liquid flow that flows toward the outside of the substrate; the prism portion is provided below the rotating substrate, The foreign matter evaporated and removed from the surface of the substrate by the evanescent light is washed away to the outside of the substrate by the rinse liquid flow.

14. 3. The substrate processing apparatus according to claim 2, a rotation unit that rotates the substrate holding unit, which holds the substrate in a horizontal position, about a rotation axis that passes through the center of the substrate, the prism unit includes a fourth prism having an annular shape centered on the rotation axis, having a suction path penetrating from an upper surface to a lower surface, and capable of supporting a peripheral surface portion of the substrate from below at the upper surface; The substrate holding unit integrally holds the prism unit and the substrate by sucking the substrate on the fourth prism through the suction path.

15. a first step of holding a substrate having foreign matter attached to its surface on a substrate holder; a second step of irradiating the substrate held by the substrate holder with light having directionality in a wavelength range that includes the absorption spectrum of the foreign matter; a third step of removing the foreign matter by the light irradiated onto the substrate, In the second step, an incident angle of the light with respect to an incident region where the light is incident on the substrate is smaller than a total reflection angle, and the light incident on the substrate through the incident region is totally reflected inside the substrate at an angle equal to or larger than the total reflection angle with respect to a direction perpendicular to the surface of the substrate, In the third step, the light is totally reflected on or near the surface of the substrate, and the evanescent light seeps out of the surface of the substrate, and the foreign matter absorbs the evanescent light and evaporates and removes it.

Images