JP7536676B2 - Anodizing apparatus and anodizing method - Google Patents

Description

Embodiments of the present invention relate to an anodizing apparatus and an anodizing method.

A technique is known for forming a porous film on the surface of a substrate by anodization.

JP 2004-214237 A JP 2006-131969 A JP 2006-114783 A

We provide an anodizing device and an anodizing method that can form a porous film with excellent in-plane uniformity on the surface of a substrate.

The anodizing apparatus according to the embodiment includes a first treatment tank capable of anodizing a substrate, a holder capable of holding the substrate, a first electrolytic solution supply system capable of supplying a first electrolytic solution to the first treatment tank , a positive electrode provided in the holder, a second treatment tank provided in the first treatment tank, a negative electrode provided in the second treatment tank, and a diffusion plate installed at one end of the second treatment tank in a state inclined with respect to a bottom surface of the first treatment tank. The holder immerses the substrate in the first electrolytic solution with the substrate inclined with respect to the liquid level of the first electrolytic solution. The anodizing process is performed with the substrate inclined with respect to the liquid level of the first electrolytic solution.

FIG. 1 is a configuration diagram of an anodizing apparatus according to the first embodiment. FIG. 2 is a view for explaining a rotating state of the anode holder in the anodizing apparatus according to the first embodiment. FIG. 3 is a flowchart of the anodizing process in the anodizing apparatus according to the first embodiment. FIG. 4 is a diagram showing the overall configuration of an anodizing system according to the second embodiment.

The following describes the embodiments with reference to the drawings. In the following description, components having substantially the same functions and configurations are given the same reference numerals, and repeated explanations are given only when necessary. Furthermore, each of the embodiments described below is an example of an apparatus or method for embodying the technical idea of the embodiment, and the technical idea of the embodiment does not specify the material, shape, structure, arrangement, etc. of the components as described below.

1. First embodiment An anodizing apparatus according to a first embodiment will be described. In this embodiment, an anodizing apparatus that forms a porous layer of silicon (e.g., a porous Si layer) on a surface of a semiconductor substrate (hereinafter, simply referred to as a "substrate") will be described.

1.1 Basic Configuration of Anodizing Apparatus First, an example of the basic configuration of an anodizing apparatus will be described with reference to Fig. 1. Fig. 1 is a configuration diagram of an anodizing apparatus.

As shown in FIG. 1, the anodizing device 1 includes an anodizing tank 10, an anode holder 11, a first electrolyte supply system 13, a concentration adjustment unit 14, a temperature adjustment unit 15, a second electrolyte supply system 16, a current source 17, and a control circuit 18.

The anodizing tank 10 is a treatment tank used for anodizing. The anodizing tank 10 has, for example, a cylindrical shape. The inner diameter of the anodizing tank 10 is larger than the outer diameter of the anode holder 11. An insulating material is used for the anodizing tank 10.

Pipes 201 and 202 are connected to the anodization tank 10. Pipe 201 is used to supply the first electrolytic solution from the first electrolytic solution supply system 13 to the anodization tank 10. The first electrolytic solution is a liquid used in anodization treatment, and is an electrolytic solution containing at least hydrogen fluoride (HF). Pipe 202 is used to return the first electrolytic solution from the anodization tank 10 to the first electrolytic solution supply system 13.

Inside the anodizing tank 10, there is a negative electrode tank 101, a negative electrode (cathode) 102, a filter 103, and a diffusion plate 104.

When the first electrolytic solution is supplied to the anodizing bath 10, the cathode bath 101 functions as a showerhead housing in combination with the diffusion plate 104. The cathode bath 101 has, for example, a cylindrical shape. The inner diameter of the cathode bath 101 is preferably equal to or larger than the outer diameter of the substrate 110 to be anodized. An insulating material is used for the cathode bath 101. The bottom surface of the cathode bath 101 is in contact with the bottom surface inside the anodizing bath 10. The opening at the upper end of the cathode bath 101 is inclined with respect to the bottom surface of the cathode bath 101 so that the diffusion plate 104 is attached at an angle with respect to the liquid level of the first electrolytic solution.

The negative electrode 102 functions as a cathode in the anodization process. The negative electrode 102 has, for example, a disk shape. The negative electrode 102 is in contact with the bottom surface of the negative electrode tank 101. The diameter of the negative electrode 102 is, for example, the same as the inner diameter of the negative electrode tank 101. The negative electrode 102 is made of a conductive material, and a material that has low reactivity with the first electrolyte (is hardly dissolved in the first electrolyte) is used. The negative electrode 102 may be made of a conductive material, for example, using carbon, diamond, Pt, Au, or the like as a coating material. The coating material may also be glassy fiber carbon, diamond-coated silicon, or the like.

The filter 103 is provided above the negative electrode 102 in the negative electrode tank 101. In other words, the filter 103 is provided between the negative electrode 102 and the diffusion plate 104. The filter 103 removes particles generated at the negative electrode 102 during anodization. For example, even if a material that is difficult to dissolve in the first electrolyte is used as the electrode material of the negative electrode 102, oxidation of the electrode may progress due to aging or the like, and particles may be generated. If particles are generated, the formation of porous silicon by anodization may be hindered. The size of particles that can be removed by the filter 103 can be designed arbitrarily. For example, a filter capable of removing particles with a particle size of 0.01 μm or more may be used as the filter 103.

In this embodiment, one end of the pipe 201 is provided to penetrate the bottom of the anodization tank 10, the bottom of the cathode tank 101, the cathode 102, and the filter 103, and the first electrolyte is supplied from the first electrolyte supply system 13 into the cathode tank 101.

The diffusion plate 104 is fixed to the opening at the upper end of the cathode chamber 101 in a state inclined at an angle θ (0°<θ<90°) with respect to the liquid level of the first electrolytic solution (or the bottom surface of the anodization chamber 10 and the cathode chamber 101). The diffusion plate 104 has a plurality of holes for diffusing the first electrolytic solution, and the diameter and arrangement of the holes can be designed arbitrarily. After being diffused by the diffusion plate 104, the first electrolytic solution is supplied to the surface (the surface to be anodized) of the substrate 110 fixed to the anode holder 11. Hereinafter, the surface on which a porous layer is formed by the anodization process is referred to as the surface of the substrate 110, and the surface on which a porous layer is not formed is referred to as the back surface of the substrate 110. The diffusion plate 104 is made of an insulating material, and a material that is low in reactivity (hardly dissolves) with respect to the first electrolytic solution is used. For example, it is preferable to use PTFE (Poly-Tetra-Fluoro-Ethylene), polyvinyl chloride, or a material with antistatic properties for the diffusion plate 104.

The anode holder 11 functions as a holder for fixing the substrate 110. During anodization, the anode holder is immersed in the first electrolyte together with the substrate 110.

The anode holder 11 includes a base 111, anode 112, and a wafer clamp 113.

The base 111 has, for example, a disk shape. The diameter of the base 111 is, for example, equal to or greater than the diameter of the substrate 110. The base 111 is made of, for example, an insulating material.

The positive electrode 112 functions as an anode in the anodization process. The positive electrode 112 has, for example, a disk shape. The diameter of the positive electrode 112 is, for example, the same as the diameter of the base 111. The positive electrode 112 is in contact with the bottom surface of the base 111 when at least a part of the anode holder 11 and the substrate 110 are immersed in the first electrolyte in the anodization tank 10. The positive electrode 112 is made of a conductive material, and for example, a material that is low in reactivity with the second electrolyte described below is used. The positive electrode 112 may be made of a conductive material, for example, a coating material such as carbon, diamond, Pt, Au, etc. The coating material may also be glassy fiber carbon, diamond-coated silicon, etc.

The wafer clamp 113 has a cylindrical shape. For example, grooves are provided on the side of the wafer clamp 113 for fixing the base 111 and the anode 112. An edge seal is provided on the lower end of the wafer clamp 113 for fixing the substrate 110. The outer diameter of the wafer clamp 113 is larger than the outer diameters of the substrate 110, the base 111, and the anode 112. The edge seal of the wafer clamp 113 contacts the entire outer periphery of the substrate 110 so that the surface of the substrate 110 faces downward (toward the diffusion plate 104) when at least a portion of the anode holder 11 and the substrate 110 are immersed in the first electrolyte in the anodization tank 10, and fixes the substrate 110.

The wafer clamp 113 fixes the substrate 110 and the anode 112 so that the back surface (non-anodized surface) of the substrate 110 does not come into contact with the anode 112 and the substrate 110 and the anode 112 are parallel to each other. The wafer clamp 113 is made of an insulating material that is low in reactivity (hardly dissolves) with the first and second electrolytic solutions. For example, the diffusion plate 104 is preferably made of PTFE, polyvinyl chloride, or a material that has been treated to prevent static electricity.

In this embodiment, in order to establish electrical continuity between the substrate 110 and the anode 112, a conductive second electrolyte is supplied from the second electrolyte supply system into a space formed by the back surface of the substrate 110, the anode 112, and the wafer clamp 113. More specifically, the anode holder 11 is connected to a pipe 203 for supplying the second electrolyte from the second electrolyte supply system 16 to the anode holder 11, and a pipe 204 for returning the second electrolyte to the second electrolyte supply system 16. The pipes 203 and 204 are provided so as to penetrate the base 111 and the anode 112, and the second electrolyte is supplied from the second electrolyte supply system into the above-mentioned space. In other words, the space between the anode 112 and the substrate 110 is filled with the second electrolyte.

During anodization, the second electrolyte may be electrolyzed and gas may be generated in the space described above. In such a case, a path for releasing the gas may be provided in the anode holder 11.

In this example, the case where the second electrolytic solution is supplied between the substrate 110 and the positive electrode 112 to establish electrical continuity between the substrate 110 and the positive electrode 112 has been described, but this is not limiting. For example, the back surface of the substrate 110 may be in contact with the positive electrode 112. A low-resistance layer implanted with a high concentration of dopant or a metal that can make ohmic contact with the substrate 110 may be provided on the surface of the positive electrode 112 that contacts the substrate 110.

The anode holder drive mechanism 12 is fixed to the center of the upper surface of the base 111. When at least a part of the anode holder 11 and the substrate 110 are immersed in the first electrolyte in the anodization tank 10, the base 111 can be rotated by the anode holder drive mechanism 12. In other words, the anode holder drive mechanism 12 rotatably fixes the base 111 to the center of the surface of the base 111 opposite to the surface on which the anode 112 is installed. The anode holder drive mechanism 12 has a mechanism for immersing at least a part of the base 111 in the anodization tank 10 with the base 111 inclined at an angle θ and rotating it in that state. As a result, at least a part of the anode holder 11 and the substrate 110 of this embodiment are immersed in the first electrolyte in the anodization tank 10 with the first electrolyte inclined at an angle θ with respect to the liquid surface. The anode holder driving mechanism 12 tilts the substrate 110 and the positive electrode 112 by an angle θ, so that the substrate 110, the positive electrode 112, and the diffusion plate 104 are arranged in a parallel state during anodization. The substrate 110, the positive electrode 112, and the diffusion plate 104 are arranged in a parallel state, so that the in-plane uniformity of the current density on the substrate 110 is improved. The positive electrode 112 and the diffusion plate 104 may or may not be arranged in a parallel state. Even if the positive electrode 112 and the negative electrode 102 are not arranged in a parallel state and the distance between the positive electrode 112 and the negative electrode 102 is not uniform, the substrate 110 and the diffusion plate 104 are arranged in a parallel state, so that the in-plane uniformity of the current density on the substrate 110 can be improved. Furthermore, the diffusion plate 104 is inclined in the same direction as the substrate 110 with respect to the bottom surface of the anodization tank 10 or the liquid surface of the first electrolyte, improving the in-plane uniformity of the current density on the substrate 110.

A specific example of the rotation state of the anode holder 11 is described with reference to Figure 2. Figure 2 shows a cross section of the anode holder 11 and the top surface of the base 111 in the rotated state.

As shown in FIG. 2, the anode holder driving mechanism 12 rotates the base 111 with the anode holder driving mechanism 12 as the rotation axis while tilting the base 111 at an angle θ. By tilting the base 111 at an angle θ, the substrate 110 and the anode 112 are also tilted at an angle θ. For example, the anode holder driving mechanism 12 rotates the base 111 and the substrate 110 in the range of 10 to 100 rpm.

Next, the first electrolytic solution supply system 13 will be described with reference to FIG. 1. The first electrolytic solution supply system 13 supplies the first electrolytic solution to the anodization tank 10. The first electrolytic solution is a liquid used in the anodization process. For example, a liquid containing hydrogen fluoride (HF) is used as the first electrolytic solution. More specifically, for example, a mixed solution of an HF solution and ethanol or IPA (isopropyl alcohol) is used as the first electrolytic solution. The first electrolytic solution supply system 13 of this embodiment has a function for circulating the first electrolytic solution between the anodization tank 10 and the first electrolytic solution supply system 13. The first electrolytic solution supply system 13 supplies the first electrolytic solution having a concentration adjusted into the cathode tank 101 through the piping 201, and recovers the first electrolytic solution from the anodization tank 10 through the piping 202. The first electrolytic solution supply system 13 does not have to have a function for circulating the first electrolytic solution. In this case, the pipe 202 is discarded, and the first electrolyte in the anodizing tank 10 is treated as waste liquid.

The first electrolyte supply system 13 includes a raw material supply section 131, a mixing tank 132, and a pump 133.

The raw material supply unit 131 supplies raw materials for the first electrolyte to the mixing tank 132 based on the control of the control circuit 18 and the concentration adjustment unit 14. The raw materials may be, for example, an HF solution, alcohol, DIW (deionized water), etc. Note that materials other than liquids may also be used as the raw materials.

The mixing tank 132 is a tank for mixing the first electrolytic solution recovered from the anodizing tank 10 using the piping 202 with the raw materials supplied from the raw material supply unit 131 to produce a first electrolytic solution that can be used for anodizing.

The pump 133 pumps the first electrolytic solution produced in the mixing tank 132 into the cathode tank 101 via the pipe 201. The pump 133 may also be used to send the first electrolytic solution in the mixing tank 132 to a waste liquid line (not shown). A separate pump may also be provided for the waste liquid line.

The concentration adjusting unit 14 adjusts the concentration of the first electrolytic solution. The concentration adjusting unit 14 includes a concentration sensor 141. The concentration sensor 141 is connected to the pipe 201. The concentration sensor 141 measures the ion concentration of the first electrolytic solution supplied from the first electrolytic solution supply system 13. The concentration adjusting unit 14 feeds back the measurement result of the concentration sensor 141 to the raw material supply unit 131 to adjust the supply amount of raw material in the raw material supply unit 131. Thereby, the concentration of the first electrolytic solution supplied to the anodizing bath 10 is kept constant, and H ₂ SiF ₆ , which is a by-product of the anodizing process, and the like are filtered out. The concentration adjusting unit 14 may be provided in the first electrolytic solution supply system 13.

The temperature adjustment unit 15 adjusts the temperature of the first electrolytic solution. The temperature adjustment unit 15 includes a temperature sensor 151. The temperature sensor 151 is connected to the piping 201 and monitors the temperature of the first electrolytic solution. For example, the temperature adjustment unit 15 includes a chiller or heater, and cools and heats the first electrolytic solution according to the results of the temperature monitoring. In this way, the temperature adjustment unit 15 keeps the temperature of the first electrolytic solution in the anodization tank 10 constant. The temperature adjustment unit 15 may be provided in the first electrolytic solution supply system 13.

The second electrolytic solution supply system 16 supplies a second electrolytic solution into the anode holder 11. The second electrolytic solution is used to establish electrical continuity between the anode 112 and the substrate 110. The second electrolytic solution is a liquid containing at least a material having electrical conductivity. More specifically, for example, the material having electrical conductivity may contain at least one of HF, HCl, NaCl, KCl, KOH, H ₃ PO ₄ , and TMAH (Tetra-Methyl-Ammonium-Hydroxide).

The second electrolyte supply system 16 of this embodiment has a function for circulating the second electrolyte between the anode holder 11 and the mixing tank 162. The second electrolyte supply system 16 supplies the second electrolyte having an adjusted concentration into the anode holder 11 via the pipe 203, and recovers the second electrolyte from the anode holder 11 via the pipe 204. The second electrolyte supply system 16 does not need to have a function for circulating the second electrolyte. In this case, the pipe 204 is discarded, and the second electrolyte in the anode holder 11 is treated as waste liquid.

The second electrolyte supply system 16 includes a raw material supply section 161, a mixing tank 162, and a pump 163.

The raw material supply unit 161 supplies raw materials for the second electrolytic solution to the mixing tank 162 under the control of the control circuit 18. The raw materials may be solutions such as HF, HCl, NaCl, KCl, KOH, H ₃ PO ₄ , and TMAH, and DIW (deionized water), etc. Note that materials other than liquids may be used as the raw materials.

The mixing tank 162 is a tank for mixing the second electrolyte recovered from the anode holder 11 using the piping 204 with the raw materials supplied from the raw material supply unit 161 to produce the second electrolyte.

The pump 163 pumps the second electrolytic solution produced in the mixing tank 162 into the anode holder 11 via the pipe 203. The pump 163 may also be used to pump the second electrolytic solution in the mixing tank 162 to a waste liquid line. A separate pump may also be provided for the waste liquid line. The pump 163 may set the supply pressure of the second electrolytic solution higher than the supply pressure of the first electrolytic solution so that the entire outer periphery of the substrate 110 is pressed against the edge seal of the wafer clamp 113.

The current source 17 is connected to the anode 112 and the cathode 102, and supplies a given current to the anode 112 during anodization.

The control circuit 18 controls the entire anodizing apparatus 1. More specifically, the control circuit 18 controls the anode holder drive mechanism 12, the first electrolyte supply system 13, the concentration adjustment unit 14, the temperature adjustment unit 15, the second electrolyte supply system 16, and the current source 17.

1.2 Anodizing Process Flow Next, an example of the anodizing process flow will be described with reference to Fig. 3. Fig. 3 is a flow chart of the anodizing process.

As shown in FIG. 3, first, the first electrolyte supply system 13 starts supplying the first electrolyte to the anodization tank 10 (step S1).

The substrate 110 is set in the anode holder 11 so that the back surface of the substrate 110 (the surface not to be anodized) faces the anode 112 (step S2).

The second electrolyte supply system 16 starts supplying the second electrolyte to the anode holder 11 (step S3). This causes the space between the substrate 110 and the anode 112 to be filled with the second electrolyte.

The anode holder drive mechanism 12 tilts the anode holder 11 (base 111) at an angle θ, with the substrate 110 set thereon and the second electrolyte being supplied thereto. The anode holder drive mechanism 12 then immerses at least a portion of the anode holder 11 and the substrate 110 in the first electrolyte in the anodization tank 10, tilting them at an angle θ with respect to the liquid surface (step S4). By tilting the anode holder 11, it is possible to prevent air (air bubbles) from being entrained during immersion. The first electrolyte is circulated between the anodization tank 10 and the first electrolyte supply system 13.

Next, the anode holder drive mechanism 12 starts rotating the anode holder 11 (step S5). The anode holder 11 rotates while being inclined at an angle θ with respect to the liquid surface. In addition, the anode holder only needs to be rotated while being inclined with respect to the liquid surface, and is not limited to the same inclination angle as when immersed.

The current source 17 supplies a current between the positive electrode 112 and the negative electrode 102 (step S6). While the current source 17 is supplying a current, anodization is performed. This forms a porous layer on the surface of the substrate 110.

After the current source 17 stops supplying current, the anode holder drive mechanism 12 stops rotating the anode holder 11 (step S7).

Next, the anode holder drive mechanism 12 removes the anode holder 11 from the anodization tank 10 (step S8).

The second electrolyte supply system 16 stops supplying the second electrolyte to the anode holder 11 (step S9).

The substrate 110 is recovered from the anode holder 11 (step S10).

1.3 Effects of this embodiment The configuration of this embodiment can provide an anodizing apparatus capable of forming a porous film with excellent in-plane uniformity on a substrate surface.

For example, when HF in the electrolyte reacts with the silicon substrate during anodization, the HF concentration in the electrolyte decreases, and hydrogen gas and H ₂ SiF ₆ (SiF ₆ ^2- ions) are generated as by-products. This may cause the composition (ion concentration) of the electrolyte to change, leading to poor uniformity of the porous layer within the substrate surface or for each substrate. In addition, during anodization, a double electric field layer is generated on the substrate surface, in which positive and negative charged particles form pairs and are arranged in layers, which may slow down the supply of ions to the substrate surface and the discharge of by-products.

In contrast, in the configuration according to the present embodiment, the anodizing apparatus 1 can immerse the substrate 110 in a tilted state with respect to the first electrolytic solution. Furthermore, the anodizing apparatus 1 can perform anodizing while rotating the substrate 110 in a tilted state. This allows the anodizing apparatus 1 to suppress the entrainment of air (air bubbles) when the substrate 110 is immersed in the first electrolytic solution. Furthermore, the anodizing apparatus 1 can efficiently discharge gas (e.g., hydrogen) and by-products (e.g., SiF ₆ ²⁻ ) generated on the substrate surface during anodizing from the substrate surface. Furthermore, the anodizing apparatus 1 can increase the flow rate of the first electrolytic solution on the substrate surface by rotating the substrate 110, thereby reducing the thickness of the electric field double layer formed near the surface of the substrate 110. Therefore, the anodizing apparatus 1 can improve the uniformity of ions supplied to the substrate surface, and can improve the in-plane uniformity of the formed porous layer (the uniformity of the film thickness and the in-plane uniformity of the porosity (void ratio) of the porous layer).

Furthermore, with the configuration according to this embodiment, the anodizing apparatus 1 can place the diffusion plate 104 between the positive electrode 112 and the negative electrode 102 during anodizing so that the diffusion plate 104 is parallel to the substrate 110. This can improve the uniformity of the current density within the surface of the substrate 110. This can improve the uniformity of the surface of the porous layer that is formed.

Furthermore, in the configuration according to this embodiment, the anodizing apparatus 1 has a first electrolyte supply system. This allows the concentration of the first electrolyte in the anodizing tank 10 to be kept constant, suppressing changes in the concentration of the first electrolyte during anodizing and for each substrate. This improves the uniformity of the film quality in the depth direction of the porous layer formed on the substrate 110 and the uniformity of the film quality between substrates.

Furthermore, with the configuration according to this embodiment, the anodizing apparatus 1 can supply the second electrolytic solution between the positive electrode 112 and the substrate 110. This can prevent contact between the positive electrode 112 and the substrate 110. Therefore, metal contamination of the substrate 110 by the positive electrode 112 can be reduced.

Furthermore, in the configuration according to this embodiment, by supplying a second electrolytic solution between the positive electrode 112 and the substrate 110, poor electrical continuity between the positive electrode 112 and the substrate 110 caused by warping of the positive electrode 112 or the substrate 110, etc., can be suppressed.

2. Second embodiment Next, a second embodiment will be described. In the second embodiment, a specific example of an anodizing system including a plurality of the anodizing tanks 10 described in the first embodiment will be described.

2.1 Configuration of anodizing system An example of an anodizing system will be described with reference to Fig. 4. Fig. 4 is a plan view showing the configuration of an anodizing system 300.

As shown in FIG. 4, the anodizing system 300 includes a process module 301, a transfer module 302, a load port 303, and a load module 304.

The process module 301 is a module for performing various processes on the substrate 110. In the example of FIG. 4, for example, the process module 301 includes three anodizing tanks 310-312 and two cleaning tanks 313 and 314. The anodizing tanks 310-312 correspond to the anodizing tank 10 described in the first embodiment. For example, the compositions of the first electrolytic solutions in the anodizing tanks 310-312 may be different so that anodizing can be performed under different conditions. The cleaning tanks 313 and 314 are used for pre- or post-cleaning of the anodizing. For example, the cleaning tanks 313 and 314 may be single-wafer spin cleaning devices. The configuration of the process module 301 is not limited to this. For example, a processing unit different from the anodizing tank and the cleaning tank may be installed. The number of anodizing tanks and cleaning tanks is arbitrary.

The transfer module 302 is disposed within the process module 301. The transfer module 302 includes a handler 320. The handler 320 is configured to be drivable so as to transport the substrate 110 to each tank within the process module 301.

The load port 303 opens and closes, for example, a FOUP (Front Opening Unified Pod) 330. A FOUP (Front Opening Unified Pod) is set on the load port 303. The FOUP 330 is an airtight container for transporting the substrates 110. The FOUP 330 can store multiple substrates 110. Note that while the example in FIG. 4 shows a case where four load ports 303 are arranged, the number of load ports may be one or more.

The load module 304 includes a handler 340. The handler 340 is configured to be operable so as to transport the substrate 110 between the FOUP 330 and the transfer module 302.

2.2 Effects of this embodiment The anodizing treatment device described in the first embodiment can be applied to the anodizing treatment system of this embodiment.

The anodizing apparatus according to the above embodiment includes a first treatment tank 10 capable of anodizing a substrate, a holder 11 capable of holding the substrate, and a first electrolytic solution supply system 13 capable of supplying a first electrolytic solution to the first treatment tank. The holder immerses the substrate in the first electrolytic solution while the substrate is inclined relative to the liquid level of the first electrolytic solution. The anodizing is performed while the substrate is inclined relative to the liquid level of the first electrolytic solution.

Note that the embodiment is not limited to the above-described form, and various modifications are possible.

For example, the substrate may be a semiconductor wafer, a substrate for heterogeneous computing, a substrate for MEMS (Micro Electro Mechanical Systems), a semiconductor wafer for three-dimensional integrated circuits, a substrate for biomedical applications, a substrate for optical waveguides, etc.

In addition, "connected" in the above embodiment also includes a state in which something else is interposed and indirectly connected.

In addition, "substantially the same" or "parallel" in the above embodiment includes an error that does not affect the formation of the porous layer when performing anodizing.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention.

Reference Signs List 1: Anodizing apparatus, 10: Anodizing tank, 11: Anode holder, 12: Anode holder drive mechanism, 13: First electrolyte supply system, 14: Concentration adjustment section, 15: Temperature adjustment section, 16: Second electrolyte supply system, 17: Current source, 18: Control circuit, 101: Cathode tank, 102: Cathode, 103: Filter, 104: Diffusion plate, 110: Substrate, 111: Base, 112: Positive electrode, 113: Wafer clamp, 131: Raw material supply unit, 132...mixing tank, 133...pump, 141...concentration sensor, 151...temperature sensor, 161...raw material supply unit, 162...mixing tank, 163...pump, 201-204...piping, 300...anodizing system, 301...process module, 302...transfer module, 303...load port, 304...load module, 310-312...anodizing tank, 313, 314...cleaning tank, 320, 340...handler

Claims (6)

a first treatment tank capable of performing anodizing on a substrate;
A holder capable of holding the substrate;
a first electrolytic solution supply system capable of supplying a first electrolytic solution to the first treatment tank ;
a positive electrode provided within the holder;
a second treatment tank provided within the first treatment tank;
a negative electrode provided in the second treatment tank;
a diffusion plate installed at one end of the second treatment tank in a state inclined with respect to a bottom surface of the first treatment tank;
the holder immerses the substrate in the first electrolytic solution in a state in which the substrate is inclined with respect to a liquid surface of the first electrolytic solution;
the anodizing is performed in a state where the substrate is inclined with respect to the liquid surface of the first electrolytic solution.
Anodizing equipment. During the anodizing, the holder rotates.
The anodizing apparatus according to claim 1 . During the anodizing process, the substrate and the diffusion plate are both disposed in an inclined state with respect to a bottom surface of the first treatment tank.
The anodizing apparatus according to claim 1 . During the anodization , the substrate and the diffusion plate are arranged in parallel.
The anodizing apparatus according to claim 1 . Further comprising a second electrolytic solution supply system capable of supplying a second electrolytic solution between the positive electrode and the substrate.
The anodizing apparatus according to claim 1 . supplying a first electrolytic solution to a treatment tank;
placing a substrate in a holder so as to face a positive electrode provided in the holder;
filling a space between the positive electrode and the substrate with a second electrolytic solution;
immersing the substrate set in the holder in the first electrolytic solution while being inclined with respect to a liquid surface of the first electrolytic solution;
rotating the substrate and the holder in an inclined state;
and flowing a current between the positive electrode and a negative electrode provided in the treatment tank.