JP2014212253A - Substrate cleaning method and substrate cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate cleaning method which can prevent generation of particles.SOLUTION: In a substrate cleaning method, when a mask layer 49 including an SiOfilm 45 and an SiN film 46, and an end noble metal layer 53 are removed from an end of a wafer W, oxygen GCIB (Gas Cluster Ion Beam) 23 is irradiated and a CF-based gas is supplied toward the end of the wafer W, and further, the oxygen GCIB 23 is irradiated and an acetic acid gas is supplied toward the end, and the oxygen GCIB 23 is irradiated only on a part of the end and the wafer W is rotated in a manner such that all of the ends are irradiated by the oxygen GCIB 23.

Description

  The present invention relates to a substrate cleaning method and a substrate cleaning apparatus for removing a noble metal film from an end portion of a substrate.

  In recent years, MRAM (Magnetoresistive Random Access Memory) (magnetoresistance memory) has been developed as a next-generation nonvolatile memory that replaces DRAM and SRAM. The MRAM has an MTJ (Magnetic Tunnel Junction) element instead of a capacitor, and performs storage using the magnetization state.

  In the MRAM, a plurality of metal films constituting the MRAM are formed on a semiconductor wafer (hereinafter simply referred to as “wafer”) by sputtering, and then these metal films are etched according to a predetermined pattern using a lithography technique. However, the MRAM is not formed from the vicinity of the edge of the wafer because the film thickness is not stable, and each metal film remains on the edge of the wafer.

  The wafer on which the MRAM is formed is accommodated in a FOUP (Front Opening Unified Pod) which is a container. At this time, each metal film remaining on the edge of the wafer is peeled off and adheres to another wafer accommodated in the FOUP. There is a risk of so-called metal contamination.

  However, the metal film constituting the MRAM includes a noble metal film, for example, a Ta film or a Ru film, but these noble metal films are difficult to etch and difficult to remove by wet etching using a chemical solution.

  Thus, for example, as shown in Patent Document 1, each metal film remaining on the edge of the wafer is removed using a polishing belt that grinds the edge of the wafer.

JP 2000-758

  By the way, when each metal film is ground using a polishing belt, a large amount of particles are generated, and thus there is a possibility that the particles cannot be completely removed from the ground wafer. The surface roughness of the end surface after grinding depends on the size of the abrasive grains of the polishing belt, but since the size of the abrasive grains is in units of μm, the end surface after grinding is rough. There is a possibility that particles are easily generated by rubbing with the member. That is, there is a risk that particles generated from the ground wafer adhere to other wafers in the FOUP.

  An object of the present invention is to provide a substrate cleaning method and a substrate cleaning apparatus that can prevent the generation of particles.

  In order to achieve the above object, a substrate cleaning method according to claim 1, wherein the silicon-based film and the noble metal film are removed from a substrate having a noble metal film and a silicon-based film covering the noble metal film at an end. The silicon-based film removing step of irradiating the end portion with oxygen GCIB (Gas Cluster Ion Beam) and supplying a CF-based gas, and irradiating the end portion with oxygen GCIB And a noble metal film removing step for supplying an organic acid gas.

  The substrate cleaning method according to claim 2 is the substrate cleaning method according to claim 1, wherein the organic acid is an organic acid containing a carboxyl group.

  The substrate cleaning method according to claim 3 is the substrate cleaning method according to claim 1 or 2, wherein the substrate has a disk shape, the oxygen GCIB irradiates only a part of the end portion, and the oxygen The substrate is rotated so that all of the end portions are irradiated by GCIB.

  The substrate cleaning method according to claim 4 is the substrate cleaning method according to any one of claims 1 to 3, wherein the substrate is adsorbed to an adsorption table that swings with respect to the GCIB of oxygen. When irradiating GCIB of oxygen toward the end, the adsorption table is swung with respect to the GCIB of oxygen together with the substrate.

  The substrate cleaning method according to claim 5 is the substrate cleaning method according to any one of claims 1 to 4, wherein in the silicon-based film removal step, a chemical reaction between the CF-based gas and the silicon-based film is performed. The generated reaction product is detected, and when the reaction product is not detected, it is determined that the removal of the silicon-based film is completed.

  To achieve the above object, a substrate processing apparatus according to claim 6, wherein a GCIB irradiation apparatus that irradiates GCIB of oxygen toward an end portion of a substrate having a noble metal film and a silicon-based film covering the noble metal film, An adsorption table for adsorbing a substrate; and a gas supply device for supplying a CF-based gas and an organic acid gas toward an end of the substrate adsorbed by the adsorption table. Only the portion is irradiated with the oxygen GCIB, and the adsorption stage rotates the substrate so that all of the end portions are irradiated with the oxygen GCIB.

  The substrate processing apparatus according to claim 7 is the substrate processing apparatus according to claim 6, further comprising a shielding substrate that covers a surface of the substrate and exposes an end portion of the substrate, and the shielding substrate is made of a nonmetal. It is characterized by.

  The substrate processing apparatus according to claim 8 is the substrate processing apparatus according to claim 7, wherein the shielding substrate is made of silicon.

  The substrate processing apparatus according to claim 9 is the substrate processing apparatus according to any one of claims 6 to 8, wherein a portion of the adsorption table irradiated with the GCIB of oxygen is covered with at least silicon. And

  The substrate processing apparatus according to claim 10 is the substrate processing apparatus according to any one of claims 6 to 9, wherein the suction table is attached to a goniometer.

  The substrate processing apparatus according to claim 11 is the substrate processing apparatus according to any one of claims 6 to 10, further comprising a Faraday cup ammeter facing the GCIB irradiation device via an end portion of the substrate. The Faraday cup ammeter measures the GCIB intensity of the irradiated oxygen.

  The substrate processing apparatus according to claim 12 is the substrate processing apparatus according to any one of claims 6 to 11, wherein mass for monitoring a reaction product generated by a chemical reaction between the CF-based gas and the silicon-based film. A gas analyzer is further provided.

  In order to achieve the above object, a substrate cleaning method according to claim 13, wherein the silicon-based film and the noble metal film are removed from a substrate having a noble metal film and a silicon-based film covering the noble metal film at an end. Then, the GCIB of oxygen is irradiated, the initial value of the intensity of GCIB of the irradiated oxygen is measured, the end of the substrate is moved toward the GCIB of the oxygen, and the end of the substrate is moved In the meantime, the GCIB intensity of the oxygen is measured, and when the measured oxygen GCIB intensity falls below the initial value, the movement of the substrate is stopped and the substrate is rotated with respect to the center of the substrate. A CF-based gas is supplied toward the edge of the substrate, and a reaction product generated by a chemical reaction between the CF-based gas and the silicon-based film is monitored. When an object is not detected, the supply of the CF-based gas is stopped, an organic acid gas is supplied toward the edge of the substrate, and the oxide of the noble metal film generated by the GCIB irradiation of the oxygen is The precious metal in the scattered matter generated by decomposition by the organic acid is monitored, and when the precious metal is not detected, the supply of the organic acid gas is stopped and the irradiation of the oxygen GCIB is also stopped.

  According to the present invention, oxygen GCIB is irradiated toward the end portion and a CF-based gas is supplied, and oxygen GCIB is irradiated toward the end portion and an organic acid gas is supplied. Therefore, the silicon-based film and the noble metal film can be removed without grinding, and the end surface after removing the silicon-based film and the noble metal film is not roughened. As a result, the generation of particles can be prevented.

It is sectional drawing which shows schematically the structure of the substrate processing apparatus which concerns on embodiment of this invention. It is sectional drawing which shows schematically the structure of the GCIB irradiation apparatus in FIG. It is sectional drawing which shows roughly the laminated structure of each metal film for forming MRAM in the surface of a wafer. It is sectional drawing which shows roughly the lamination | stacking state of the mask layer and edge part metal layer in the edge part of a wafer. It is a flowchart which shows the edge part cleaning process of the wafer as a substrate cleaning method which concerns on this Embodiment. It is a figure for demonstrating the swing motion of the stage in the removal of the mask layer and edge part metal layer from the edge part of a wafer. It is a figure for demonstrating the removal of the mask layer from the edge part of a wafer using the swing motion of FIG. It is a figure for demonstrating the removal of the edge part metal layer from the edge part of a wafer using the swing motion of FIG. It is a figure which shows schematically the structure of the modification of the stage in FIG. It is sectional drawing which shows roughly the structure of the modification of the GCIB irradiation apparatus in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, a substrate processing apparatus according to an embodiment of the present invention will be described.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a substrate processing apparatus according to the present embodiment.

  In FIG. 1, a wafer edge cleaning apparatus 10 (substrate processing apparatus) includes a chamber 11 that accommodates a semiconductor wafer (hereinafter simply referred to as “wafer”), and a wafer holding unit 12 that is erected from the bottom of the chamber 11. A GCIB irradiation device 13 provided on the inner wall of the chamber 11, a Faraday cup ammeter 14, a mass gas analyzer 15 and a processing gas nozzle 16 (gas supply device) provided in the chamber 11, and wafer edge cleaning. And a control unit 17 that controls the operation of each component of the apparatus 10.

  The wafer holding unit 12 includes a stage 18 (suction table) on which the wafer W is placed and sucked by electrostatic force or the like, and a goniometer 19 that supports the stage 18. The goniometer 19 has a base 20 disposed at the bottom of the chamber 11 and a columnar shaft 21 extending upward from the base 20, and the base 20 is configured to be movable in the vertical and horizontal directions in the figure. The shaft 21 is configured to be rotatable about a central axis and is configured to be able to be bent at a substantially midpoint. That is, the base 20 and the shaft 21 cooperate to move the stage 18 for attracting the wafer W in the X direction and the Y direction in the figure, and rotate in the θ direction and the φ direction in the figure, resulting in the stage 18 being moved to the wafer. Swing with W.

  The wafer holding unit 12 further includes a disk-shaped shadow wafer 22 (shielding substrate) whose diameter is smaller than that of the wafer W by a predetermined value. The shadow wafer 22 covers the surface of the wafer W attracted to the stage 18. The wafer W is covered so as not to come into contact with the surface, and the end of the wafer W is exposed. In the wafer holding unit 12, the stage 18 is made of a metal such as aluminum, while the shadow wafer 22 is made of a non-metal such as silicon.

  The GCIB irradiation device 13 irradiates a GCIB (Gas Cluster Ion Beam) 23 of oxygen along the horizontal direction in the figure, and the Faraday cup ammeter 14 faces the GCIB irradiation device 13 and receives the GCIB 23 of oxygen. The Faraday cup ammeter 14 is composed of a cup-shaped member that is horizontally laid down, and measures the secondary electrons scattered from the bottom by the GCIB 23 of the received oxygen to measure the intensity of the GCIB 23 of oxygen.

  The processing gas nozzle 16 is configured to switch and supply a plurality of types of reaction gases, for example, CF-based gas and acetic acid gas, and to move in the horizontal direction (X ′ direction) in the figure, and the mass gas analyzer 15 is a substance that scatters For example, the components of the reaction product are analyzed at the atomic level.

  FIG. 2 is a cross-sectional view schematically showing the configuration of the GCIB irradiation apparatus in FIG.

  In FIG. 2, the GCIB irradiation device 13 includes a cylindrical main body 24 that is disposed substantially horizontally and whose inside is decompressed, a nozzle 25 that is disposed at one end of the main body 24, a plate-shaped skimmer 26, and an ionizer. 27, an accelerator 28, and a permanent magnet 29.

  The nozzle 25 is disposed along the central axis of the main body 24 and ejects oxygen gas along the central axis. The skimmer 26 is disposed so as to cover a cross section in the main body 24, and a central portion protrudes toward the nozzle 25 along the central axis of the main body 24, and has a narrow hole 30 at the top of the protruding portion. The other end of the main body 24 also has a beam passage hole 31 in a portion corresponding to the central axis of the main body 24.

  The ionizer 27, the accelerator 28, and the permanent magnet 29 are all disposed so as to surround the central axis of the main body 24. The ionizer 27 emits electrons toward the central axis of the main body 24 by heating the built-in filament. Causes a potential difference along the central axis of the main body 24, and the permanent magnet 29 generates a magnetic field in the vicinity of the central axis of the main body 24.

  In the GCIB irradiation device 13, a nozzle 25, a skimmer 26, an ionizer 27, an accelerator 28 and a permanent magnet 29 are arranged in this order from one end side (left side in the figure) to the other end side (right side in the figure) of the main body 24. The

  When oxygen gas is ejected toward the inside of the main body 24 whose pressure is reduced by the nozzle 25, the volume of the oxygen gas rapidly increases, and the oxygen gas undergoes rapid adiabatic expansion to rapidly cool the oxygen molecules. When each oxygen molecule is rapidly cooled, the kinetic energy is reduced and the oxygen molecules are brought into close contact with each other due to the intermolecular force (van der Waals force) acting between the oxygen molecules. 32 is formed.

  The skimmer 26 selects only the oxygen gas cluster 32 moving along the central axis of the main body 24 from the plurality of oxygen gas clusters 32 by the narrow holes 30, and the ionizer 27 moves the oxygen gas cluster moving along the central axis of the main body 24. The oxygen gas cluster 32 is ionized by colliding electrons with 32, the accelerator 28 accelerates the ionized oxygen gas cluster 32 to the other end side of the main body 24 due to a potential difference, and the permanent magnet 29 has a relatively small oxygen due to a magnetic field. The course of the gas cluster 32 (including the monomer of ionized oxygen molecules) is changed. In the permanent magnet 29, the relatively large oxygen gas cluster 32 is also affected by the magnetic field, but because the mass is large, the course is not changed by the magnetic force, and the movement continues along the central axis of the main body 24.

  The relatively large oxygen gas cluster 32 that has passed through the permanent magnet 29 passes through the beam passage hole 31 at the other end of the main body 24, is ejected out of the main body 24, and is irradiated horizontally into the chamber 11 as oxygen GCIB 23.

  In the wafer edge cleaning device 10, when the GCIB irradiation device 13 irradiates the GCIB 23 of oxygen, the wafer holding unit 12 moves the stage 18 and the wafer W in the X direction, the Y direction, and rotates in the θ direction and the φ direction. Properly, the GCIB 23 of oxygen is irradiated to the end of the wafer W that is not covered by the shadow wafer 22. At this time, the processing gas nozzle 16 supplies a reaction gas toward the end of the wafer W, and the mass gas analyzer 15 analyzes the constituent atoms of the reaction product scattered from the end of the wafer W.

  FIG. 3 is a cross-sectional view schematically showing a laminated structure of each metal film for forming the MRAM on the surface of the wafer.

In FIG. 3, the laminated structure 33 includes a Ta film 35, a Ru film 36, a Ta film 37, a PtMn film 38, a CoFe film 39, and a Ru film that are sequentially laminated on the SiO ₂ film 34 formed on the surface of the wafer W. 40, a CoFeB film 41, a MgO film 42, a CoFeB film 43, a Ta film 44, a SiO ₂ film 45, and a SiN film 46. The SiO ₂ film 34, the Ta film 35, the Ru film 36, the Ta film 37, the PtMn film 38, the CoFe film 39, and the Ru film 40 constitute an underlayer 47, and the CoFeB film 41, the MgO film 42, and the CoFeB film 43 are MTJ elements. 48, and the SiO ₂ film 45 and the SiN film 46 constitute a mask layer 49. From the laminated structure 33, each of the metal films 35 to 35 is formed using the Ta film 44, the SiO ₂ film 45 and the SiN film 46 as a hard mask. 44 is etched in a predetermined pattern to form an MRAM.

In the laminated structure 33, the metal films 35 to 44 described above are formed by sputtering, and then covered with the SiO ₂ film 45 and the SiN film 46, so that the bottom surface of the wafer W is as shown in FIG. The ground layer 47, the MTJ element 48, and the mask layer 49 are laminated. Further, various noble metals scattered when the metal films 35 to 44 are etched are stacked at the end of the wafer W to form an end noble metal layer 53, and the end noble metal layer 53 is also covered by the mask layer 49. .

  Usually, since device chips such as MRAM are not formed near the end of the wafer W, the end noble metal layer 53 exists below the mask layer 49 at the end of the wafer W even after the MRAM is formed on the wafer W. Even if the mask layer 49 is removed, the end noble metal layer 53 contains each noble metal constituting the base layer 47, for example, Ru, Ta, and Pt, and thus is difficult to remove with a chemical solution.

  In the substrate cleaning method according to the present embodiment, the mask layer 49 and the end noble metal layer 53 remaining on the edge of the wafer W are removed using oxygen GCIB.

  FIG. 5 is a flowchart showing wafer edge cleaning processing as the substrate cleaning method according to the present embodiment. This edge cleaning process is executed by the control unit 17 controlling the operation of each component in the wafer edge cleaning apparatus 10.

  First, after the wafer W is adsorbed to the stage 18, the wafer W is covered with the shadow wafer 22, and further, the GCIB irradiation device 13 irradiates the Faraday cup ammeter 14 with the oxygen GCIB 23, and the Faraday cup ammeter 14 The intensity of the GCIB 23 of oxygen that is not shielded by the wafer W or the like is measured as an initial value (step S501).

  Next, the wafer holding unit 12 moves the stage 18 and the wafer W in the X direction and the Y direction, and rotates in the θ direction and the φ direction so that the end of the wafer W not covered by the shadow wafer 22 is covered with the GCIB 23 of oxygen. (Step S502), while the Faraday cup ammeter 14 continues to measure the intensity of the GCIB 23 of oxygen (step S503).

  Thereafter, when the intensity of the oxygen GCIB 23 falls below the initial value, the control unit 17 determines that a portion of the edge of the wafer W has started to be irradiated with the oxygen GCIB 23, stops the movement of the wafer W, The shaft 21 is rotated about the central axis, and the wafer W is rotated in the θ direction together with the stage 18 (step S504). As a result, the entire end portion of the wafer W is irradiated with the GCIB 23 of oxygen.

Next, the processing gas nozzle 16 is moved to face the end of the wafer W, and a CF-based gas such as CF ₄ or C ₅ F ₈ gas is supplied from the processing gas nozzle 16 toward the end of the wafer W. (Step S505) (silicon-based film removal step).

  At this time, the chemical reaction of the CF-based gas and the mask layer 49 is promoted by the kinetic energy of the oxygen gas cluster 32 of the oxygen GCIB 23 at the edge of the wafer W, and the mask layer 49 changes to a silicon-based reaction product. . Since the reaction product has a high vapor pressure, it is easily sublimated by the energy applied from the oxygen gas cluster 32. Thereby, the mask layer 49 is chemically removed.

  The sublimated reaction product is analyzed as a scattered matter by the mass gas analyzer 15, and in particular, the reaction product in the scattered matter is monitored (step S506), and the control unit 17 determines whether or not the reaction product is detected. Determination is made (step S507).

  If the reaction product is detected as a result of the determination in step S507, it is determined that the mask layer 49 remains and the chemical reaction of the CF-based gas and the mask layer 49 continues, and the process returns to step S505, and the CF If Si is not detected, it is determined that the mask layer 49 does not remain, and the supply of the CF-based gas is stopped and the carboxyl group is transferred from the processing gas nozzle 16 to the edge of the wafer W. An organic acid containing, for example, acetic acid gas is supplied (step S508) (precious metal film removing step).

  At this time, oxidation of the end noble metal layer 53 is promoted by the kinetic energy of the oxygen gas cluster 32 of the GCIB 23 of oxygen at the end of the wafer W, and oxides of noble metals such as Ru, Ta, and Pt are generated. Since the vapor pressure of the noble metal oxide is also high, it is easily sublimated by the energy applied from the oxygen gas cluster 32, and the noble metal oxide is easily decomposed by acetic acid. Thereby, the end noble metal layer 53 is chemically removed.

  The sublimated and decomposed oxide is analyzed as a scattered matter by the mass gas analyzer 15, and particularly, Ta and Ru in the scattered matter are monitored (step S509), and the control unit 17 determines whether Ta or Ru is detected. Is determined (step S510).

  If Ta or Ru is detected as a result of the determination in step S510, it is determined that the end noble metal layer 53 remains and oxidation of the end noble metal layer 53 continues, and the process returns to step S508, and the acetic acid gas On the other hand, if Ta or Ru is not detected, it is determined that the end noble metal layer 53 does not remain, and the supply of acetic acid gas is stopped, and the irradiation of oxygen GCIB 23 is also stopped. Exit.

  According to the wafer edge cleaning process of FIG. 5, since the oxygen GCIB 23 is irradiated toward the edge of the wafer W and the CF gas is supplied, the CF gas due to the kinetic energy of the oxygen gas cluster 32 is supplied. The mask layer 49 is chemically removed through the promotion of the chemical reaction of the gas and the mask layer 49. Further, since the GCIB 23 of oxygen is irradiated toward the end portion of the wafer W and acetic acid gas is supplied, the oxidation of the end noble metal layer 53 by the kinetic energy of the oxygen gas cluster 32 is promoted, and further, the noble metal by acetic acid is The end noble metal layer 53 is chemically removed through the decomposition of the oxide. That is, the end noble metal layer 53 and the mask layer 49 can be removed without grinding, and the end surface of the wafer W after the end noble metal layer 53 and the mask layer 49 are removed is not roughened. Generation of particles can be prevented.

  In the wafer edge cleaning process of FIG. 5 described above, an organic acid containing a carboxyl group is supplied from the process gas nozzle 16. Since the organic acid having a carboxyl group easily decomposes and removes the noble metal oxide, the end noble metal layer 53 can be reliably removed. The organic acid containing a carboxyl group is not limited to the acetic acid described above, and may be hfac (hexafluoroacetylacetone), for example.

  5, the oxygen GCIB 23 irradiates only a part of the end of the wafer W, and the wafer holding unit 12 irradiates all of the end of the wafer W by the oxygen GCIB 23. As described above, the wafer W is rotated about the central axis of the shaft 21, so that the entire wafer W is GCIB 23 of oxygen in order to promote the chemical reaction of the CF-based gas and the mask layer 49 and the oxidation of the end noble metal layer 53. It is not necessary to irradiate with oxygen, and it is not necessary to increase the beam diameter of the GCIB 23 of oxygen. As a result, energy for generating oxygen GCIB 23 can be saved. In general, an effective film formation region where a device chip such as an MRAM is formed is a region within 1 mm to 2 mm from the edge of the wafer W, and therefore the beam diameter of the oxygen GCIB 23 is preferably 2 mm or less.

  Further, in the wafer edge cleaning process of FIG. 5, since the shadow wafer 22 made of non-metallic silicon covers the surface of the wafer W, the semiconductor device formed on the surface of the wafer W is damaged by the GCIB 23 of oxygen. Can be prevented. Further, even if particles are generated from the shadow wafer 22 by the stray cluster in the oxygen gas cluster 32 of the oxygen GCIB 23, the particles are made of silicon, so that the wafer W can be prevented from being contaminated with metal.

  By the way, each film constituting the mask layer 49 is formed by sputtering, and further, the end noble metal layer 53 is constituted by various kinds of precious metals scattered, and therefore, as shown in FIG. W may wrap around the side or back of W.

  In the substrate cleaning method according to the present embodiment, correspondingly, when removing the mask layer 49 and the end noble metal layer 53 at the end of the wafer W, the stage 18 is caused to swing with the wafer W, As shown in FIGS. 6A to 6C, oxygen GCIB 23 is irradiated to the front surface, side surface, and back surface of the end portion of the wafer W. Specifically, when removing the mask layer 49 and the end noble metal layer 53 from the surface of the end portion of the wafer W, the stage 18 is tilted so that the surface of the wafer W faces the GCIB irradiation apparatus 13 (FIG. 6). (A)) When removing the mask layer 49 and the end noble metal layer 53 from the side surface at the end of the wafer W, the stage 18 is tilted so that the wafer W is substantially perpendicular to the oxygen GCIB 23 (FIG. 6 (B)), when removing the mask layer 49 and the end noble metal layer 53 from the back surface of the end portion of the wafer W, the stage is set so that the surface of the wafer W is directed to the opposite side to the GCIB irradiation device 13. 18 is tilted (FIG. 6C). When the stage 18 is swung, the relative position of the end of the wafer W and the processing gas nozzle 16 changes. Therefore, the processing gas nozzle 16 is moved each time the stage 18 moves, and the processing gas nozzle 16 is moved to the end of the wafer W. Directly face the part.

  FIG. 7 is a diagram showing how the mask layer 49 is removed when the stage in FIG. 1 is swung, and FIG. 8 is an end portion when the stage in FIG. 1 is swung. FIG. 6 is a diagram showing how the noble metal layer 53 is removed.

  In step S505 of FIG. 5, when the surface of the wafer W is directed to the GCIB irradiation device 13 as shown in FIG. 6A, the oxygen GCIB 23 is irradiated on the surface of the end portion of the wafer W and the mask is masked from the surface. When the layer 49 is removed (FIG. 7A) and the wafer W is substantially perpendicular to the oxygen GCIB 23 as shown in FIG. 6B, the oxygen GCIB 23 is irradiated to the side surface of the end portion of the wafer W. Then, the mask layer 49 is removed from the side surface (FIG. 7B). Further, as shown in FIG. 6C, when the surface of the wafer W is directed to the side opposite to the GCIB irradiation apparatus 13, the wafer W The back surface at the end of the substrate is irradiated with oxygen GCIB 23 to remove the mask layer 49 from the back surface (FIG. 7C).

  In step S508 of FIG. 5, as shown in FIG. 6A, when the surface of the wafer W is directed to the GCIB irradiation device 13, the surface of the end portion of the wafer W is irradiated with oxygen GCIB23, and the surface The edge noble metal layer 53 is removed from the wafer W (FIG. 8A), and when the wafer W is made substantially perpendicular to the oxygen GCIB 23, as shown in FIG. The end portion noble metal layer 53 is removed from the side surface by irradiating the GCIB 23 (FIG. 8B), and the surface of the wafer W is moved to the opposite side of the GCIB irradiation apparatus 13 as shown in FIG. 6C. When directed, the back surface of the end portion of the wafer W is irradiated with oxygen GCIB 23, and the end noble metal layer 53 is removed from the back surface (FIG. 8C).

  That is, in the substrate cleaning method according to the present embodiment, the stage 18 is swung together with the wafer W, so that the mask layer 49 and the edge are not only from the surface of the end of the wafer W but also from the side and back of the end. The partial noble metal layer 53 can be reliably removed.

  Although the present invention has been described using the above embodiment, the present invention is not limited to the above embodiment.

For example, CF ₄ or C ₅ F ₈ gas is supplied as a CF-based gas in step S505, but the CF-based gas is not limited to these, and any product capable of reacting with SiO ₂ or SiN to produce a product. Can be used. However, the higher the molecular weight, the lower the vapor pressure, and the easier it is to adsorb to the SiO ₂ film 45 or SiN film 46. Therefore, when CF gas molecules are represented by CxFy, x and y are preferably larger.

  Further, the mass gas analyzer 15 is used for detecting the end point of the removal of the end noble metal layer 53 and the mask layer 49 in step S506 and step S509. May be used.

  Further, as shown in FIG. 6C, in order to remove the end noble metal layer 53 and the mask layer 49 on the back surface of the end portion of the wafer W, the surface of the wafer W is directed to the opposite side to the GCIB irradiation device 13. If the stage 18 is tilted in this manner, the stage 18 may be directly irradiated to the oxygen GCIB 23. Therefore, as shown in FIG. 9, the stage 18 may be irradiated to the oxygen GCIB 23, specifically, The vicinity of the end of the stage 18 is preferably covered with a sacrificial film 50 made of a nonmetallic material, for example, silicon. In this case, even if particles are scattered from the sacrificial film 50 by the GCIB 23 of oxygen, for example, since the particles are made of silicon, the wafer W can be prevented from being contaminated with metal even if it adheres to the wafer W.

  If an aperture plate having aperture holes is provided in the GCIB irradiation apparatus 13, the oxygen gas cluster 32 sputters the aperture plate to generate particles from the aperture plate, and the particles may adhere to the wafer W. Therefore, the GCIB irradiation apparatus 13 does not include an aperture plate, but when the aperture plate is made of a non-metal, for example, silicon, even if particles generated from the aperture plate adhere to the wafer W, the wafer W is not contaminated with metal. As shown in FIG. 10, an aperture plate 51 may be provided in the GCIB irradiation device 13. In this case, the aperture plate 51 is arranged between the accelerator 28 and the permanent magnet 29 so that the aperture plate 51 also covers the transverse section in the main body 24, and has an aperture hole 52 in a portion corresponding to the central axis of the main body 24. The aperture plate 51 sorts out only the oxygen gas clusters 32 moving along the central axis of the main body 24 from the oxygen gas clusters 32 accelerated by the accelerator 28 by the aperture holes 52. Further, when the main body 24 is made of a non-metal, for example, silicon, the diameter of the beam passage hole 31 may be reduced to function as an aperture hole.

  5 can also be applied to the removal of the end noble metal layer at the end of the wafer W having a laminated structure other than the laminated structure 33 if a noble metal film is present. .

  An object of the present invention is to supply a computer, for example, the control unit 17 with a storage medium storing software program codes for realizing the functions of the above-described embodiments, and the CPU of the control unit 17 is stored in the storage medium. It is also achieved by reading and executing the program code.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Examples of the storage medium for supplying the program code include RAM, NV-RAM, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD (DVD). -ROM, DVD-RAM, DVD-RW, DVD + RW) and other optical disks, magnetic tapes, non-volatile memory cards, other ROMs, etc., as long as they can store the program code. Alternatively, the program code may be supplied to the control unit 17 by downloading from another computer or database (not shown) connected to the Internet, a commercial network, a local area network, or the like.

  Further, by executing the program code read by the control unit 17, not only the functions of the above embodiments are realized, but also an OS (operating system) running on the CPU based on the instruction of the program code. Includes a case where the functions of the above-described embodiment are realized by performing part or all of the actual processing.

  Furthermore, after the program code read from the storage medium is written to the memory provided in the function expansion board inserted into the control unit 17 or the function expansion unit connected to the control unit 17, the program code is read based on the instruction of the program code. Also included is a case where the CPU of the function expansion board or function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

  The form of the program code may include an object code, a program code executed by an interpreter, script data supplied to the OS, and the like.

W Wafer 10 Wafer edge cleaning device 11 Chamber 12 Wafer holding unit 13 GCIB irradiation device 16 Processing gas nozzle 18 Stage 22 Shadow wafer 23 GCIB of oxygen
49 Mask layer 50 Sacrificial film 53 End noble metal layer

Claims (13)

A substrate cleaning method for removing the silicon-based film and the noble metal film from a substrate having a noble metal film and a silicon-based film covering the noble metal film at an end,
A silicon-based film removing step of irradiating oxygen GCIB (Gas Cluster Ion Beam) toward the end and supplying a CF-based gas;
And a noble metal film removing step of irradiating GCIB of oxygen toward the end portion and supplying an organic acid gas.   The substrate cleaning method according to claim 1, wherein the organic acid is an organic acid containing a carboxyl group.   The substrate has a disk shape, and the oxygen GCIB irradiates only a part of the end, and the substrate is rotated so that the oxygen GCIB irradiates all of the end. The substrate cleaning method according to claim 1 or 2. Adsorbing the substrate to an adsorption table that swings against the GCIB of oxygen,
4. The apparatus according to claim 1, wherein when the oxygen GCIB is irradiated toward the end portion, the adsorption table is swung with respect to the oxygen GCIB together with the substrate. 5. Substrate cleaning method.   In the silicon-based film removal step, a reaction product generated by a chemical reaction of the CF-based gas and the silicon-based film is detected, and if the reaction product is not detected, it is determined that the removal of the silicon-based film is completed. The substrate cleaning method according to any one of claims 1 to 4. A GCIB irradiation apparatus for irradiating GCIB of oxygen toward an end portion of a substrate having a noble metal film and a silicon-based film covering the noble metal film;
An adsorption platform for adsorbing the substrate;
A gas supply device for supplying a CF-based gas and an organic acid gas toward the end of the substrate adsorbed by the adsorption table;
The GCIB irradiation apparatus irradiates only a part of the end with the oxygen GCIB,
The substrate processing apparatus, wherein the adsorption stage rotates the substrate so that all of the end portions are irradiated with the oxygen GCIB. A shielding substrate that covers the surface of the substrate and exposes an end of the substrate;
The substrate processing apparatus according to claim 6, wherein the shielding substrate is made of a nonmetal.   The substrate processing apparatus according to claim 7, wherein the shielding substrate is made of silicon.   9. The substrate processing apparatus according to claim 6, wherein at least a portion of the adsorption table irradiated with GCIB of oxygen is covered with silicon.   The substrate processing apparatus according to claim 6, wherein the suction table is attached to a goniometer.   The Faraday cup ammeter that is opposed to the GCIB irradiation device through an end portion of the substrate is further provided, and the Faraday cup ammeter measures the intensity of the GCIB of the irradiated oxygen. The substrate processing apparatus according to any one of 10.   The substrate processing apparatus according to claim 6, further comprising a mass gas analyzer that monitors a reaction product generated by a chemical reaction between the CF-based gas and the silicon-based film. A substrate cleaning method for removing the silicon-based film and the noble metal film from a substrate having a noble metal film and a silicon-based film covering the noble metal film at an end,
Irradiate with GCIB of oxygen,
Measure the initial value of the GCIB intensity of the irradiated oxygen,
Moving the edge of the substrate towards the oxygen GCIB;
Measure the GCIB intensity of the oxygen while moving the edge of the substrate,
When the measured GCIB strength of oxygen is lower than the initial value, the movement of the substrate is stopped, and the substrate is rotated with respect to the center of the substrate,
Supply CF gas toward the edge of the substrate,
Monitoring reaction products generated by chemical reaction of the CF-based gas and the silicon-based film;
When the reaction product is not detected, the supply of the CF-based gas is stopped, and an organic acid gas is supplied toward the edge of the substrate.
Monitoring the noble metal in the scattered matter generated by the decomposition of the oxide of the noble metal film generated by the GCIB irradiation of oxygen by the organic acid;
When the noble metal is not detected, supply of the organic acid gas is stopped, and irradiation of the oxygen GCIB is also stopped.

Images