JP2004197145A - Electrolytic treatment apparatus and electrolytic treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-purpose electrolytic treatment apparatus and electrolytic treatment method which realize a cleaning effect adaptive to new materials and manufacturing processes introduced in a semi-conductor device, and also meet a need for a cleaning technology which is expected to be more increased as the semi-conductor device becomes finer and highly integrated. <P>SOLUTION: The multi-purpose electrolytic apparatus comprises a substrate holding unit 3 to hold a substrate W, an anode electrode unit 21 and a cathode electrode unit 22 disposed in the vicinity of the substrate holding unit so as to face the substrate W held by the substrate holding unit 3, treatment solution feed units 27 and 25 to feed the treatment solution between the substrate held by the substrate holding unit 3, the anode electrode unit 21 and the cathode electrode unit 22, and a power source 32 to apply the voltage between the anode electrode unit 21 and the cathode electrode unit 22. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrolytic processing apparatus and an electrolytic processing method for removing an object to be processed such as a metal or a resist material, an etching residue, and particles formed on a surface of a substrate such as a semiconductor wafer by using electric energy. is there.
[0002]
[Prior art]
In a semiconductor device manufacturing process, a high degree of cleanliness is required, and a cleaning technique for removing submicron-level stains is becoming increasingly important. In particular, as the miniaturization and high integration of semiconductor devices progress, it is desired to realize a new cleaning technique corresponding to a new material and a manufacturing process being introduced into semiconductor devices.
[0003]
New materials being introduced into semiconductor devices include metals such as Cu, Ru, Co, and Pt. Of these, Cu (copper) tends to cause metal contamination, and thus it is necessary to completely remove excess Cu remaining on the substrate. Cu is difficult to remove by the conventional RCA cleaning method, and is generally removed using an HF-based processing solution. Ozone water (O₃The cleaning method using ()) can remove most metals, but cannot completely remove Cu.
[0004]
In recent years, with further miniaturization of semiconductor devices, there is a tendency to use a low-k material as an insulating film. With the introduction of the low-k material, a new cleaning technique that enables removal of the polymer after the low-k material is etched and cleaning of the inside of the fine contact hole formed in the low-k material has been developed. Is desired. Since the diameter of the fine contact hole (wiring hole) is extremely small, there has been a problem that cleaning failure easily occurs inside the contact hole. In addition, it is becoming more difficult to clean the inside of the contact hole due to the further miniaturization of the diameter of the contact hole and the water repellency of the Low-k material.
[0005]
Further, ashing after the formation of the wiring hole causes damage to the low-k material, and thus ashing occurs.₂Plasma can no longer be used and a new wet resist stripping process is required. Further, with the introduction of new materials and miniaturization of semiconductor devices described above, the semiconductor device manufacturing process itself is changing. Therefore, realization of a new cleaning technique corresponding to a change in the manufacturing process is required. For example, with the introduction of new resist materials and changes in the etching process, the adhesion strength of polymers and resist residues to underlying layers such as insulating films may be higher than before, and conventional cleaning techniques can remove them. It is considered difficult.
[0006]
Further, in a semiconductor device that is being miniaturized, it is necessary to remove particles having a smaller particle size. Further, recently, there is a concern about a problem of organic contamination generated in a semiconductor device manufacturing process.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and can provide a cleaning effect corresponding to a new material and a manufacturing process being introduced into a semiconductor device. Further, the semiconductor device can be miniaturized and highly integrated. It is an object of the present invention to provide a versatile electrolytic processing apparatus and an electrolytic processing method that can meet the needs for a cleaning technique that is expected to increase further in the future.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a substrate holding unit that holds a substrate, an anode electrode unit and a cathode electrode unit that are arranged to face the substrate held by the substrate holding unit, A processing liquid supply unit that supplies a processing liquid between the substrate held by the unit and the anode electrode unit and the cathode electrode unit, and a power supply that applies a voltage between the anode electrode unit and the cathode electrode unit. , Is provided.
In this case, a driving mechanism for bringing the anode electrode section and the cathode electrode section close to the substrate held by the substrate holding section and a rotation driving mechanism for rotating the substrate held by the substrate holding section are further provided. Is preferred.
[0009]
According to the present invention, a positive potential is applied to a conductive substance (an object to be processed) formed on a surface of a substrate by a so-called bipolar phenomenon, and the conductive substance can be oxidized and electrically dissolved.
[0010]
In a preferred aspect of the present invention, the treatment liquid contains an electrolyte.
The main purpose of including the electrolyte in the treatment liquid is to impart good conductivity to the treatment liquid. In the case where a halide having a strong oxidizing power such as hydrogen chloride (HCl) is used as the electrolyte, the object to be treated can be removed by using an ionized halogen ion to enhance the oxidation of the object.
[0011]
Another preferred aspect of the present invention is that the waveform of the current flowing through the anode electrode portion and the cathode electrode portion is at least one of an AC waveform, a DC waveform, a DC reverse voltage waveform, a pulse waveform, a PR pulse waveform, and a double pulse waveform. The rectifier further includes a rectifier for rectifying the rectifier.
According to the present invention, not only oxidation of a conductive substance but also various objects to be processed present on a substrate can be removed by flowing an optimal current according to an object to an anode electrode portion and a cathode electrode portion. . For example, when dissolving a metal formed on the surface of a substrate, a DC waveform utilizing a bipolar phenomenon is selected, and when removing particles, the electric mobility of an ionic surfactant is used instead of the bipolar phenomenon. Pulse waveforms and PR pulse waveforms are selected for use. If it is necessary to make the substrate surface a reducing atmosphere, a reverse voltage waveform of direct current or pulse is selected, and the molecular structure of water is refined to increase the permeability of the processing solution. In the case of performing the conversion, a pulse waveform having a fine wavelength on the order of microseconds (μs) is selected.
[0012]
Another preferred embodiment of the present invention is that a plurality of the anode electrode portions are arranged at equal intervals along a vertical direction and a horizontal direction on the same plane, and the plurality of the cathode electrode portions are two adjacent to each other in an oblique direction. It is characterized in that it is arranged at a substantially central part of the anode electrode part.
In another preferred aspect of the present invention, a plurality of the cathode electrode portions are arranged at equal intervals along a vertical direction and a horizontal direction on the same plane, and the plurality of the anode electrode portions are adjacent to each other in an oblique direction. It is characterized in that it is arranged at a substantially central portion between the two cathode electrode portions.
According to the present invention, uniform processing can be performed over the entire substrate.
[0013]
In another preferred aspect of the present invention, at least one of the anode electrode section and the cathode electrode section is made of conductive diamond or lead dioxide.
Usually, in an electrolytic treatment apparatus, Pt (white silver) is often used as an insoluble electrode. However, in the catalytic reaction of Pt, O₂Occurs but O₃Does not occur. If conductive diamond is used instead of Pt, oxygen overvoltage (from the anode to O₂The voltage at which the onset of occurrence begins)₃Can be generated. O if lead dioxide is also used as anode only₃Oxygen overvoltage which can generate is obtained. Therefore, according to the present invention, when water existing as a solvent in the treatment liquid is electrolyzed, O₂Not only O₃Can be generated. And O₃Utilizing the strong oxidizing power of the compound, it is possible to decompose and remove etching residues such as polymers and resist materials.
[0014]
In another preferred aspect of the present invention, a distance between the substrate held by the substrate holding portion and the anode electrode portion is different from a distance between the substrate held by the substrate holding portion and the cathode electrode portion. And
ADVANTAGE OF THE INVENTION According to this invention, the oxidizing power or the reducing power of the gas generated from the electrode part closer to the substrate can be applied to the processing liquid existing near the surface of the substrate, and the action of removing the processing object can be improved. Can be. In addition, when a voltage whose polarity is periodically inverted is applied between the electrode portions, a change in potential on the substrate surface can be increased. As a result, it is possible to promote the removal of an object to be processed such as particles that are electrostatically adsorbed, and further, the molecular structure of water existing as a solvent is miniaturized, and the processing liquid is injected into a minute contact hole. And the cleaning can be performed satisfactorily.
[0015]
Conventionally used ozone water production equipment is installed independently of the main body of the cleaning equipment, so when the ozone water is moved to the position of the substrate in the cleaning equipment, the ozone is generated during the movement in the piping. Decomposition sometimes did not provide a uniform ozone concentration.
In addition, since the electrolytic ion water production equipment is also installed alone, the reactive state obtained by electrolysis, dissociated ions with high electromobility, and the modified state of the solvent having a micromolecular structure are maintained on the substrate There was something I couldn't do.
In the present invention, by performing these electrolytic reactions and generation of ozone very close to the substrate, various phenomena obtained by electrolysis and ozone can be effectively exerted. Can be made faster by applying electrical auxiliary energy.
[0016]
In another preferred aspect of the present invention, a supply port of the processing liquid supply unit is provided in the anode electrode unit or the cathode electrode unit, and a suction port for sucking the processing liquid supplied from the supply port is the anode electrode unit or It is characterized in that it is provided on the cathode electrode section.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing the overall configuration of the electrolytic processing apparatus according to one embodiment of the present invention. FIG. 2 is a schematic plan view of the electrolytic processing apparatus shown in FIG.
[0018]
As shown in FIG. 1, the electrolytic processing apparatus according to the present embodiment includes a substrate holder 3 for holding a substrate W, a shaft 4 fixed below the substrate holder 3, and a lower part of the substrate holder 3. And a container 5 disposed therein. The shaft 4 is rotatably supported by a bearing (not shown), and the substrate holding unit 3 and the shaft 4 rotate integrally.
[0019]
The substrate holding unit 3 includes a circular substrate holding table 6 and a plurality of support pins 7 provided on the upper surface of the substrate holding table 6. The support pins 7 are arranged at equal intervals along the outer peripheral direction of the substrate W, and the peripheral edge of the substrate W is supported by these support pins 7. Note that the substrate can be held using a holding mechanism such as a vacuum chuck or an electrostatic chuck instead of the support pins 7. A rotation motor 8 is connected to a lower end of the shaft 4, and the substrate W held by the substrate holding unit 3 via the shaft 4 is rotated by the rotation motor 8.
[0020]
The electrolyzing apparatus according to the present embodiment includes an arm 11 that can move up and down and reciprocate on a horizontal plane, and an electrolysis head 12 fixed to an end of the arm 11. A reciprocating motor 14 is connected to the base 11a of the arm 11 via a power transmission mechanism 13 so that the reciprocating motor 14 causes the electrolytic head 12 to swing in the direction of arrow A shown in FIG. Has become. A vertical movement motor (not shown) is connected to the arm 11, and the vertical movement motor causes the electrolytic head 12 to move up and down. The electrolytic head 12 can be lowered to a position where the distance between the substrate W held by the substrate holding unit 3 and the lower end of the electrolytic head 12 is about 1 mm.
[0021]
Next, the configuration of the electrolytic head 12 will be described in detail with reference to FIGS. FIG. 3 is a sectional view of the electrolytic head shown in FIG. 1, and FIG. 4 is a view of the electrolytic head shown in FIG.
As shown in FIGS. 3 and 4, the electrolytic head 12 includes a plurality of anode electrode units 21 and a plurality of cathode electrode units 22. The anode electrode section 21 and the cathode electrode section 22 are provided on the lower end surface of the electrolytic head 12, and are arranged regularly according to a predetermined pattern.
[0022]
As shown in FIG. 4, the cathode electrode portions 22 are arranged over substantially the entire lower end surface of the electrolytic head 12, and are arranged at regular intervals in the vertical and horizontal directions. The anode electrode portions 21 are respectively disposed at central portions between the cathode electrode portions 22 that are adjacent to each other in an oblique direction. As described above, the anode electrode portion 21 and the cathode electrode portion 22 are arranged in a checkered pattern on the lower end surface of the electrolytic head 12.
[0023]
As shown in FIGS. 3 and 4, the cathode electrode portion 22 is formed inside a protruding portion 12a having a rectangular cross section that protrudes downward, and is formed in a lattice-shaped groove 12b formed between these protruding portions 12a. An anode electrode part 21 is formed. With such a configuration, a step (α mm in the present embodiment) is provided between the anode electrode unit 21 and the cathode electrode unit 22. Therefore, when the distance between the upper surface of the substrate W held by the substrate holding unit 3 and the cathode electrode unit 22 is approximately 1 mm, the distance between the anode electrode unit 21 and the upper surface of the substrate W is approximately (1 + α) mm.
[0024]
The cathode electrode section 22 is provided with a supply port 25 that penetrates the center. Each of these supply ports 25 is connected to a processing liquid supply source 27 through a pipe 26. The processing liquid is stored in the processing liquid supply source 27, and the processing liquid is supplied to the upper surface of the substrate W from the supply port 25 via the pipe 26. A suction port 29 connected to a suction source (not shown) through a pipe 28 is provided at the center of the anode electrode section 21. The processing liquid supplied to the upper surface of the substrate W is sucked from the suction port 29 by the suction source and discharged out of the system. Note that the supply port 25 may be provided at the outer edge of the cathode electrode section 22, and the suction port 29 may be provided at the outer edge of the anode electrode section 21. As shown in FIG. 3, the processing liquid supplied to the upper surface of the substrate W remains on the substrate W due to the action of surface tension, but a part of the processing liquid flows out of the substrate W. In this case, the processing liquid flowing out of the substrate W is collected by the container 5 provided below the substrate holding unit 3.
[0025]
Here, the flow of the processing liquid will be described with reference to FIGS. 5A and 5B.
FIG. 5A is an enlarged sectional view of the anode electrode section and the cathode electrode section shown in FIG. 3, and FIG. 5B is an enlarged sectional view showing another configuration example of the anode electrode section and the cathode electrode section. In the configuration example shown in FIG. 5B, the supply port 25 is provided at the outer edge of the cathode electrode section 22, and the suction port 29 is provided at the outer edge of the anode electrode section 21. The arrows shown in FIGS. 5A and 5B indicate the flow of the processing liquid.
[0026]
As shown in FIGS. 5A and 5B, the processing liquid is supplied to the upper surface of the substrate W from a supply port 25 provided in the cathode electrode unit 22, and after flowing through the upper surface of the substrate W, the processing liquid is supplied. Inhalation is performed through an intake port 29 provided in 21. As described above, regardless of whether the supply port 25 and the suction port 29 are provided at the center or the outer edge of the electrode portion, the cleaning liquid is sucked from the supply port 25 via the upper surface of the substrate W with almost the same flow. Flows through mouth 29.
[0027]
The processing liquid used in the electrolytic processing apparatus includes a solvent such as water or alcohol, and HCl or NH.₃It is basically composed of an electrolyte such as OH and an additive such as an ionic surfactant. The purpose of adding the electrolyte to the treatment liquid is mainly to impart conductivity to the treatment liquid. Further, the pH can be adjusted by adding an electrolyte to the treatment liquid, and an effect of promoting the action of removing the object can be expected. In other words, if the pH is lowered, the oxidation-reduction potential rises and a strong oxidizing power can be obtained, and if the pH is raised and turned to the alkali side, the zeta potential which is a factor of particle adsorption can be lowered, which is effective for particle removal. . Also, when a halide having a strong oxidizing power such as HCl is used as an electrolyte, a part of the halide is ionized in the processing solution to become a halogen ion, and the halogen ion reacts with the object to be removed to form an object. The processed material is oxidized.
[0028]
The anode electrode unit 21 is electrically connected to the anode of the power supply 32 via the wiring 31, and the cathode electrode unit 22 is electrically connected to the cathode of the power supply 32 via the wiring 33. As a material for forming the anode electrode portion 21 and the cathode electrode portion 22, conductive diamond is preferably used. Note that lead dioxide (PbO) was used instead of conductive diamond.₂), Silver (Pt) or the like. Here, the anode and the cathode of the power supply 32 can be inverted to remove the lead dioxide, so that the anode electrode can be used as the cathode electrode and the cathode electrode can be used as the anode electrode.
[0029]
The power supply 32 includes a rectifier (not shown) that rectifies a current waveform into a predetermined waveform. This rectifier rectifies the waveform of the current output from the power supply 32 into one of an AC waveform, a DC waveform, a DC reverse voltage waveform (a DC waveform with inverted polarity), a pulse waveform, a PR pulse waveform, and a double pulse waveform. can do. Further, the rectifier can change the frequency and wavelength of each current waveform described above. The pulse waveform described above is not limited to a sine waveform, a triangular waveform, a square, and a rectangle, and may be a combination of two or more of these waveforms.
[0030]
FIG. 6A shows a PR pulse waveform. FIG. 6B is a cross-sectional view showing the operation of the anode electrode unit and the cathode electrode unit in section a shown in FIG. 6A, and FIG. 6C is a section b shown in FIG. FIG. 5 is a cross-sectional view showing the operation of the anode electrode unit and the cathode electrode unit in FIG. In FIG. 6A, the horizontal axis represents time (t), and the vertical axis represents current magnitude (A).
[0031]
As shown in FIG. 6A, in a current having a PR pulse waveform, the direction in which the current flows changes periodically. For this reason, as shown in FIG. 6B, in section a, the cathode electrode part 22 becomes an anode and the anode electrode part 21 becomes a cathode. In section b, as shown in FIG. 6C, the cathode electrode portion 22 functions as a cathode as it is, and the anode electrode portion 21 also functions as an anode as it is.
[0032]
The current waveform, frequency, and wavelength are appropriately selected depending on the object to be processed. For example, a DC waveform is selected when dissolving the metal formed on the surface of the substrate W, and a DC reverse voltage waveform is selected when removing the resist material attached to the metal surface. When removing particles, a pulse waveform or a PR pulse waveform is selected, and when refining the molecular structure of water in the processing solution, a pulse waveform having a fine wavelength on the order of microseconds (μs) is selected. Is done. As described above, the electrolytic processing apparatus according to the present embodiment allows an optimal current according to the purpose to flow through the anode electrode unit 21 and the cathode electrode unit 22, and removes various workpieces existing on the substrate W. can do.
[0033]
Next, the operation of the electrolytic processing apparatus configured as described above will be described. In this example, the object to be removed is copper (Cu) formed on the surface of the substrate W.
First, the substrate W is held by the substrate holding unit 3 such that the surface on which the copper is formed faces upward. After the reciprocating motor 14 is driven to move the arm 11 above the substrate W, the up / down motor is driven to lower the electrolytic head 12, and the electrolytic head 12 is held by the lower end surface of the electrolytic head 12 and the substrate holder 3. Stop at a position where the distance from the upper surface of the substrate W is about 1 mm. In this state, the rotation motor 8 is driven to rotate the substrate W, and at the same time, the reciprocating motor 14 is driven to swing the electrolytic head 12.
[0034]
The processing liquid stored in the processing liquid supply source 27 is supplied to the upper surface of the substrate W from the supply port 25, and at the same time, the processing liquid on the substrate W is sucked from the suction port 29. Then, a predetermined voltage is applied between the anode electrode portion 21 and the cathode electrode portion 22 by the power supply 32, and the electrolytic treatment (electrolytic etching) proceeds. The waveform of the current output from the power supply 32 is selected according to the object to be processed. In this example, a DC waveform is selected.
[0035]
FIG. 7 is an enlarged cross-sectional view for explaining a state in which electrolytic processing for removing copper, which is a bulk metal or a contaminant metal, from the substrate is progressed by the electrolytic processing apparatus according to the present embodiment. As shown in FIG. 7, when a voltage is applied between the anode electrode portion 21 and the cathode electrode portion 22 in the presence of the processing solution containing the electrolyte, the portion of the copper 50 close to the anode electrode portion 21 has a negative potential. The portion of the copper 50 close to the cathode electrode section 22 has a positive potential. This phenomenon is called a bipolar phenomenon. An oxidation reaction of copper occurs at a portion of copper 50 to which a positive potential is applied (Cu → Cu²⁺+ 2e⁻), H at the site of copper 50 to which a negative potential is applied.₂The voltage is controlled so as to generate the voltage. A potential difference is generated inside the copper 50 so that electrons (e⁻Move). In this way, the electrolytic treatment (electrolytic etching) proceeds at the portion of the positively charged copper 50, and the copper 50 to be treated is dissolved.
[0036]
The processing liquid supplied to the upper surface of the substrate W passes through the upper surface of the substrate W, is sucked from each suction port 29, and is continuously discharged out of the system. A part of the processing liquid spills off from the surface of the substrate W, but is collected by a container 5 provided below the substrate holding unit 3. In the present embodiment, the reciprocating motor 14 is driven during the electrolytic treatment to swing the electrolytic head 12, but a scrolling movement may be performed instead of the swinging movement.
[0037]
In the electrolytic treatment for dissolving the metal, the current waveform output from the power supply 32 is set to a DC waveform, and the output voltage of the power supply 32 is set to 10 to 100V. Further, the electric resistivity between the anode electrode unit 21 and the cathode electrode unit 22 is preferably 5 to 50 Ω · cm.
[0038]
Next, a case of removing an organic substance such as a polymer or a resist attached to the surface of the substrate W using the electrolytic processing apparatus according to the present embodiment will be described with reference to FIG. As shown in FIG. 8, when removing an organic substance such as a polymer or a resist material using the electrolytic processing apparatus according to the present embodiment, the substrate surface needs a high oxidizing power and a quick reaction promoting energy. In this case, an electrode close to the substrate W is the anode electrode portion 21, and an electrode far from the substrate W is the cathode electrode portion 22.
[0039]
As a material forming the anode electrode portion 21, conductive diamond is preferably used. The reason is as follows. O from the anode electrode 21₂(Hereinafter, referred to as oxygen overvoltage) at which the generation of the gas begins to occur depends on the degree of catalytic activity of the material forming the anode electrode portion 21. This oxygen overvoltage is defined as silver (Pt) <lead dioxide (PbO₂) <Higher in the order of diamonds. Therefore, by adopting conductive diamond as the material of the anode electrode part 21, the O₂Is suppressed, and O₃The incidence rate increases.
[0040]
Generally, when removing a polymer or a resist material attached to the substrate W, ozone water (O₃) May be used. In the conventional stand-alone type ozone water producing apparatus, while the ozone water is₃However, there is a problem that the effective oxidizing power cannot be obtained due to a decrease in the concentration.
[0041]
In the present embodiment, since the conductive diamond is used for the material of the anode electrode portion 21, O₃Can be generated, and the generated O₃It is possible to effectively utilize the oxidizing power possessed by organic compounds for removing organic substances such as polymers and resist materials. O, O generated at the anode electrode portion 21₂ ⁻, O₃ ⁻For example, the oxidizing power of active oxygen species such as the above can be used. O₃The application range is further expanded by using electric energy such as a pulse waveform or the power of an electrolyte in order to increase the reaction speed.
[0042]
As described above, since the step α is provided between the anode electrode unit 21 and the cathode electrode unit 22, the distance (about 1 mm) between the anode electrode unit 21 and the substrate W is It becomes smaller than the distance to W (about (1 + α) mm). The reason for providing such a step α is to make the properties such as oxidizing or reducing properties of the processing liquid near the upper surface of the substrate W dependent on the gas generated from the electrode portion closer to the substrate W. It is. In the present embodiment, since the anode electrode unit 21 is disposed at a position closer to the substrate W than the cathode electrode unit 22, a strong oxidizing power can be applied to the processing liquid near the upper surface of the substrate W. In order to make the properties of the processing liquid uniform over the entire upper surface of the substrate W, it is preferable to arrange the anode electrode portion 21 and the cathode electrode portion 22 as small as possible.
[0043]
Further, the supply port 25 is disposed close to the substrate W, and the suction port 29 is disposed at a position farther from the substrate W than the supply port 25. Therefore, the polymer or the resist material ( The object to be processed) can be prevented from adhering to the surface of the substrate W again.
[0044]
Next, a case where the electrolytic processing apparatus according to the present embodiment removes minute particles attached to the substrate W and a case where the inside of minute contact holes formed in the Low-k material is cleaned will be described.
[0045]
Generally, it is said that the zeta potential, which is one factor causing particles to be adsorbed to the substrate W, decreases at pH 9 to 10. In the present embodiment, an ionic surfactant is suitably used as an additive to be added to the treatment liquid in order to remove fine particles. A pulse waveform is selected as a current waveform to be applied. Further, by disposing the cathode electrode portion 22 near the substrate W, a reducing power is given to the processing liquid, and NH 3 is used as an electrolyte.₃The pH is adjusted by adding OH. With such a combination, the fine particles can be wrapped with the ionic surfactant, and can be separated from the surface of the substrate W by the action of an electric field (electric field).
[0046]
When removing metal particles from the substrate W, an ionic chelating agent or plating brightener is used as an additive, and when removing organic particles having polarity, an ionic surfactant or Use organic adsorbents such as dyes. That is, the above-mentioned particles and organic substances can be adsorbed by the ionic organic adsorbate, and can be separated from the surface of the substrate W by the action of an electric field (electric field).
[0047]
When cleaning the inside of a small contact hole formed in a low-k material, the molecular structure of water is reduced by electrolyzing water existing as a solvent, and the penetration of the processing solution into the inside of the contact hole is promoted. Can be done. In particular, by using a pulse waveform as the waveform of the current flowing through the anode electrode unit 21 and the cathode electrode unit 22, the mobility of the OH having a large mobility in the processing liquid is high.⁻, H⁺The number of ions can be increased, and the treatment liquid can be more easily penetrated into the inside of the contact hole. In addition, the increase of mobile ions promotes the movement of the detached particles in the contact hole and, together with the use of the ionic organic adsorbent, releases the object to be removed existing in the contact hole to the outside of the contact hole. be able to. The above-mentioned O₃Make effective use of.
[0048]
Next, a substrate processing apparatus incorporating the electrolytic processing apparatus according to the present invention will be described in detail with reference to FIG. FIG. 9 is a plan view showing a configuration of a substrate processing apparatus provided with the electrolytic processing apparatus according to the present invention. Note that, in the following description, a configuration in which copper (Cu) formed on the surface of the substrate W is removed is shown, but the same applies to a case where another workpiece is processed.
[0049]
As shown in FIG. 9, the substrate processing apparatus includes a pair of load / unload units 37 for loading and unloading a cassette (not shown) containing a substrate W having copper as an object to be processed on its surface. The apparatus includes four electrolytic processing apparatuses 1, a transport robot 38 for transporting a substrate W, and a housing 39 for housing these devices. A transfer rail 40 is disposed at the center of the housing 39, and the transfer robot 38 can move freely on the transfer rail 40. The two electrolytic processing apparatuses 1 are disposed on both sides of the transport rail 40, and the load / unload units 37 are disposed near the ends of the transport rail 40. The transfer of the substrate W between the load / unload unit 37 and the electrolytic processing apparatus 1 is performed by the transfer robot 38.
[0050]
Next, the operation of the substrate processing apparatus configured as described above will be described.
The cassette storing the substrates W is set in the loading / unloading section 37, and one substrate W is taken out of the cassette by the transfer robot. The transport robot 38 transports the substrate W to the electrolytic processing apparatus 1 and causes the substrate holding unit 3 (see FIG. 1) of the electrolytic processing apparatus 1 to hold the substrate W. Until the substrate W is held by the substrate holding unit 3, the electrolytic head 12 waits at the retracted position indicated by the dotted line in FIG. Then, after the substrate W is held by the substrate holding unit 3, the electrolytic head 12 (see FIG. 1) moves to near the upper surface of the substrate W, and electrolytic processing (electrolytic etching) of copper on the substrate is performed. The operation of the electrolytic processing apparatus 1 is as described above, and the description is omitted here.
[0051]
After the completion of the electrolytic processing, the electrolytic head 12 moves to the above-described retreat position, and the substrate W held by the substrate holding unit 3 is returned to the cassette of the load / unload unit 37 by the transfer robot 38. Since this substrate processing apparatus includes four electrolytic processing apparatuses 1, it is possible to continuously perform electrolytic processing on a plurality of substrates W.
[0052]
【The invention's effect】
As described above, according to the present invention, a positive potential is applied to a conductive substance (object to be processed) formed on the surface of a substrate by a so-called bipolar phenomenon, and the conductive substance is oxidized and electrically dissolved. be able to. Further, water existing as a solvent in the treatment liquid is electrolyzed to generate O 2 generated from the anode electrode portion.₃In addition, organic substances such as polymers and resist materials can be removed by utilizing the strong oxidizing power of active oxygen. In addition, a reducing atmosphere can be formed to remove particles on the substrate surface, and the penetration of the processing solution into the fine pores is promoted by improving the permeability of the solvent obtained by electrolysis and the mobility of ions, Particles and organic substances in the micropores can be effectively removed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an overall configuration of an electrolytic processing apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic plan view of the electrolytic processing apparatus shown in FIG.
FIG. 3 is a cross-sectional view of the electrolytic head shown in FIG.
FIG. 4 is a diagram when the electrolytic head shown in FIG. 3 is viewed from a direction indicated by an arrow B.
5 (a) is an enlarged cross-sectional view of the anode electrode section and the cathode electrode section shown in FIG. 3, and FIG. 5 (b) is an enlarged cross section showing another configuration example of the anode electrode section and the cathode electrode section. FIG.
FIG. 6A is a diagram showing a PR pulse waveform. FIG. 6B is a cross-sectional view showing the operation of the anode electrode unit and the cathode electrode unit in section a shown in FIG. 6A, and FIG. 6C is a section b shown in FIG. FIG. 5 is a cross-sectional view showing the operation of the anode electrode unit and the cathode electrode unit in FIG.
FIG. 7 is an enlarged cross-sectional view for explaining a state in which the electrolytic processing is performed by the electrolytic processing apparatus according to the embodiment of the present invention.
FIG. 8 is a sectional view showing the electrolytic head when the anode electrode unit and the cathode electrode unit are inverted.
FIG. 9 is a plan view showing a configuration of a substrate processing apparatus provided with the electrolytic processing apparatus according to the present invention.
[Explanation of symbols]
1 electrolytic treatment equipment
3 Board holding part
4 shaft
5 containers
6 Board holding table
7 Support pins
8 Rotating motor
11 arms
12 Electrolysis head
13 Power transmission mechanism
14 Reciprocating motor
21 Anode electrode part
22 Cathode electrode
25 Supply port
26, 28 piping
27 Treatment liquid supply source
29 Inlet
31, 33 wiring
32 power supply
37 Load / Unload section
38 Transfer robot
39 Housing
40 transport rail
50 Workpiece (copper)

Claims (15)

A substrate holding unit for holding the substrate,
An anode electrode unit and a cathode electrode unit arranged so as to face the substrate held by the substrate holding unit,
A processing liquid supply unit that supplies a processing liquid between the substrate held by the substrate holding unit and the anode electrode unit and the cathode electrode unit,
An electrolytic processing apparatus comprising: a power supply for applying a voltage between the anode electrode unit and the cathode electrode unit. A drive mechanism for bringing the anode electrode portion and the cathode electrode portion close to a substrate held by the substrate holding portion,
2. The electrolytic processing apparatus according to claim 1, further comprising a rotation driving mechanism for rotating the substrate held by the substrate holding unit. The electrolytic processing apparatus according to claim 1, wherein the processing liquid includes an electrolyte. The rectifier further includes a rectifier that rectifies a waveform of a current flowing through the anode electrode unit and the cathode electrode unit into at least one of an AC waveform, a DC waveform, a DC reverse voltage waveform, a pulse waveform, a PR pulse waveform, and a double pulse waveform. The electrolytic processing apparatus according to any one of claims 1 to 3, wherein: A plurality of the anode electrode portions are arranged at equal intervals along the vertical direction and the horizontal direction on the same plane, and the plurality of the cathode electrode portions are disposed at a substantially central portion of two anode electrode portions adjacent to each other in an oblique direction. The electrolytic processing apparatus according to any one of claims 1 to 4, wherein the apparatus is arranged. A plurality of the cathode electrode portions are arranged at equal intervals along the vertical direction and the horizontal direction on the same plane, and the plurality of the anode electrode portions are disposed substantially at the center of two cathode electrode portions adjacent to each other in an oblique direction. The electrolytic processing apparatus according to any one of claims 1 to 4, wherein the electrolytic processing apparatus is arranged. The electrolytic processing apparatus according to any one of claims 1 to 6, wherein at least one of the anode electrode section and the cathode electrode section is made of conductive diamond or lead dioxide. The distance between the substrate held by the substrate holding portion and the anode electrode portion is different from the distance between the substrate held by the substrate holding portion and the cathode electrode portion. The electrolytic processing apparatus according to claim 1. A supply port of the processing liquid supply unit is provided in the anode electrode unit or the cathode electrode unit, and a suction port for sucking the processing liquid supplied from the supply port is provided in the anode electrode unit or the cathode electrode unit. The electrolytic processing apparatus according to any one of claims 1 to 8, wherein: Bring the anode and cathode electrodes close to the substrate,
Supplying a processing liquid between the substrate and the anode electrode portion and the cathode electrode portion,
An electrolytic treatment method, wherein a voltage is applied between the anode electrode unit and the cathode electrode unit. The electrolytic treatment method according to claim 10, wherein the substrate is rotated while a voltage is applied between the anode electrode unit and the cathode electrode unit. The electrolytic processing method according to claim 10, wherein the processing liquid includes an electrolyte. Supplying a current having any one of an AC waveform, a DC waveform, a DC reverse voltage waveform, a pulse waveform, a PR pulse waveform, and a double pulse waveform to the anode electrode portion and the cathode electrode portion. The electrolytic treatment method according to any one of claims 10 to 12. The distance between the substrate held by the substrate holding unit and the anode electrode unit is different from the distance between the substrate held by the substrate holding unit and the cathode electrode unit. 2. The electrolytic treatment method according to claim 1. While supplying the processing liquid to the substrate from the supply port provided in the anode electrode section or the cathode electrode section, the processing liquid supplied to the substrate is sucked from the suction port provided in the anode electrode section or the cathode electrode section. The electrolytic treatment method according to any one of claims 10 to 14, wherein the method is performed.

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