Process solution supply apparatus for semiconductor manufacturing and method for treating semiconductor materials

Abstract

To provide a process solution supply device for semiconductor manufacturing capable of producing and supplying process solutions that dissolve only a predetermined amount of chromium group elements such as molybdenum as wiring metal.SOLUTION: A process solution supply device 1 for semiconductor manufacturing comprises a pH-adjusted water production part 2 and a redox potential adjustment solvent production part 3. The pH-adjusted water production part 2 has a platinum group metal-supported resin column 22 in an ultrapure water W supply line 21, which has a pH-adjustment agent injection line 23A and a redox potential adjustment agent injection line 24A merged and which is connected to a first storage tank 25 that stores pH-adjusted water. The redox potential adjustment solvent production part 3 has a supply line 31 for an isopropyl alcohol S, with a redox potential adjusting agent injection line 32A joined and a second storage tank 33 for storing redox potential adjusting solvent disposed thereto.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a solution supply device used in a semiconductor manufacturing process, and particularly to a semiconductor manufacturing process solution supply device capable of manufacturing and supplying a treatment solution for dissolving a wiring metal by a predetermined amount in a wiring manufacturing process of a semiconductor using a chromium group element such as molybdenum as a wiring metal. Further, the present invention relates to a method for treating a semiconductor material for dissolving a wiring metal by a predetermined amount in a wiring manufacturing process of a semiconductor material using a chromium group element such as molybdenum as a wiring metal.

Background Art

[0002] With the recent miniaturization of semiconductors, the wiring width has also been steadily reduced. In the wiring manufacturing process in the conventional semiconductor manufacturing process, although wiring misalignment has occurred due to the manufacturing equipment from the past, since the wiring width was wide, the influence due to the wiring misalignment could be ignored and it did not affect the yield. However, as the miniaturization of the wiring width has progressed, the wiring misalignment that was conventionally negligible has become non-negligible because it affects the yield even if it is extremely small. The miniaturization of the wiring will continue in the future, and since the wiring misalignment is caused by the manufacturing equipment, it is difficult to prevent the occurrence of the wiring misalignment itself.

[0003] Therefore, as a method for preventing the deterioration of the performance of a semiconductor due to wiring misalignment, the development of an ultra-fine etching technology for a wiring layer has been promoted. This ultra-fine etching technology is a technology for preventing unnecessary short circuits by previously dissolving the wiring layer extremely finely and using the interlayer insulating film existing between the wirings as a dam so that the wirings do not contact each other even if wiring misalignment occurs, and is a technology required as long as miniaturization progresses.

[0004] For ultra-fine etching of wiring made of chromium group elements such as tungsten and molybdenum, wet processing is applied. A method called digital etch is commonly used, in which the metal surface is alternately treated with two liquids, ozone water and diluted hydrogen peroxide water, to repeat oxidation and dissolution of the metal surface and gradually remove the wiring metal.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in ultra-fine etching techniques such as conventional digital etch, the amount of metal dissolution (=dissolution depth, hereinafter referred to as metal loss) varies depending on the difference in wiring width (hereinafter referred to as pattern loading). Even if ultra-fine etching can be achieved, there is a problem that it has an adverse effect on the performance of the semiconductor. There is also a problem that the electrical characteristics of the semiconductor deteriorate due to an increase in the surface roughness of the wiring metal after ultra-fine etching. In particular, in the wiring manufacturing process using a chromium group element (molybdenum) as the wiring metal, it is desirable to make the metal loss constant regardless of the difference in the wiring width.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a semiconductor manufacturing process solution supply device capable of manufacturing and supplying a processing solution for dissolving a predetermined amount of wiring metal in a semiconductor wiring manufacturing process using a chromium group element such as molybdenum as the wiring metal. Another object of the present invention is to provide a method for processing a semiconductor material capable of dissolving a predetermined amount of wiring metal in a semiconductor material wiring manufacturing process using a chromium group element such as molybdenum as the wiring metal.

Means for Solving the Problems

[0007] In view of the above object, the present invention firstly provides a pH-adjusted water production unit comprising an ultrapure water supply line, a hydrogen peroxide removal mechanism disposed in the ultrapure water supply line, a pH adjustment mechanism for adding a pH adjuster to the ultrapure water from which hydrogen peroxide has been removed so as to achieve a predetermined pH, a first water quality monitoring mechanism for monitoring the pH of the pH-adjusted water whose pH has been adjusted, a control mechanism for controlling the addition amount of the pH adjuster by the pH adjustment mechanism so as to achieve a desired pH based on the water quality measured by the first water quality monitoring mechanism, and a first storage tank for storing the produced pH-adjusted water; a non-aqueous solvent supply line, a redox potential adjustment mechanism for adding a redox potential adjuster to the non-aqueous solvent disposed in the non-aqueous solvent supply line so as to achieve a predetermined redox potential, and a second storage tank for storing the produced redox potential-adjusted solvent; and a supply means for supplying the pH-adjusted water stored in the first storage tank and the redox potential-adjusted solvent stored in the second storage tank respectively, to provide a process solution supply device for semiconductor manufacturing (Invention 1).

[0008] According to such an invention (Invention 1), in the pH-adjusted water production unit, ultrapure water is passed from the ultrapure water supply line through the hydrogen peroxide removal mechanism to remove trace amounts of hydrogen peroxide contained in the ultrapure water. A pH adjuster is added to the ultrapure water from which hydrogen peroxide has been removed to prepare pH-adjusted water, which is then stored in the first storage tank. On the other hand, in the redox potential-adjusted solvent production unit, a non-aqueous solvent is supplied from the non-aqueous solvent supply line, and a redox potential adjuster is added to the non-aqueous solvent so as to achieve a desired redox potential to adjust the redox potential-adjusted solvent, which is then stored in the second storage tank. Since the semiconductor can be processed with the pH-adjusted water in the first storage tank and the redox potential-adjusted solvent in the second storage tank, it becomes possible to dissolve a predetermined amount of wiring metal in the wiring manufacturing process of a semiconductor that uses a chromium group element such as molybdenum as the wiring metal.

[0009] In the above invention (Invention 1), a redox potential adjusting mechanism for adding a redox potential adjusting agent so as to obtain a predetermined redox potential is provided downstream of the hydrogen peroxide removing mechanism in the ultrapure water supply line, a second water quality monitoring mechanism for monitoring the redox potential of the adjusted water whose redox potential has been adjusted, and a control mechanism for controlling the addition amount of the redox potential adjusting agent by the redox potential adjusting mechanism so as to obtain a desired redox potential based on the water quality measured by the second water quality monitoring mechanism are preferably provided (Invention 2).

[0010] According to such an invention (Invention 2), by adding a redox potential adjusting agent to ultrapure water so as to obtain a desired redox potential, pH-adjusted water (pH·redox potential adjusted water) whose redox potential has been adjusted is prepared and stored in the first storage tank. And since a semiconductor can be processed with the pH·redox potential adjusted water and the redox potential adjusting solvent in the second storage tank, it becomes possible to dissolve a predetermined amount of wiring metal in the wiring manufacturing process of a semiconductor that uses a chromium group element such as molybdenum as a wiring metal.

[0011] In the above inventions (Inventions 1 and 2), it is preferable that the supply means can alternately supply the pH-adjusted water stored in the first storage tank and the redox potential adjusting solvent stored in the second storage tank (Invention 3).

[0012] According to such an invention (Invention 3), since washing can be alternately performed with the redox potential adjusting solvent in the second storage tank and the pH-adjusted water in the first storage tank, it becomes possible to dissolve a predetermined amount of wiring metal in the wiring manufacturing process of a semiconductor that uses a chromium group element such as molybdenum as a wiring metal.

[0013] In the above inventions (Inventions 1 to 3), it is preferable that the pH adjusting agent in the pH-adjusted water production unit is one or more of ammonia, sodium hydroxide, potassium hydroxide, TMAH, and choline (Invention 4).

[0014] According to such an invention (Invention 4), by appropriately selecting these pH adjusters and appropriately adjusting their addition amounts, various pH-adjusted waters can be produced. Therefore, depending on the wiring metal and line width of the semiconductor, treatment can be performed with various pH-adjusted waters.

[0015] In the above invention (Invention 2), it is preferable that the redox potential adjuster in the pH-adjusted water production unit is one or more of hydrogen gas, oxalic acid, hydrogen sulfide, and potassium iodide (Invention 5).

[0016] According to such an invention (Invention 5), by appropriately selecting these redox potential adjusters and appropriately adjusting their addition amounts, various pH and redox potential-adjusted waters can be produced. Therefore, depending on the wiring metal and line width of the semiconductor, treatment can be performed with various pH-adjusted waters.

[0017] In the above inventions (Inventions 1 to 5), it is preferable that the redox potential adjuster in the redox potential adjustment solvent production unit is one or more of hydrogen peroxide, ozone gas, oxygen gas, nitric acid, and iodine (Invention 6).

[0018] According to such an invention (Invention 6), by appropriately selecting these redox potential adjusters and appropriately adjusting their addition amounts, various redox potential adjustment solvents can be produced. Therefore, depending on the wiring metal and line width of the semiconductor, treatment can be performed with various redox potential adjustment solvents.

[0019] In the above inventions (Inventions 2 and 4), it is preferable that the pH adjuster or redox potential adjuster in the pH-adjusted water production unit is a liquid, and the pH adjuster or redox potential adjuster is injected into the ultrapure water supply line by a pump or a pressurizing means using a sealed tank and an inert gas (Invention 7).

[0020] According to such an invention (Invention 7), the addition amount of the liquid pH adjuster or redox potential adjuster in the pH-adjusted water production unit can be easily and finely controlled.

[0021] In the above invention (Inventions 2 and 4), it is preferable that the pH adjuster or the oxidation-reduction potential adjuster in the pH-adjusted water production unit is a gas, and the pH adjuster or the oxidation-reduction potential adjuster is added by gas dissolution using a gas-permeable membrane module or a direct gas-liquid contact device using an ejector (Invention 8).

[0022] According to such an invention (Invention 8), the addition amount of the gaseous pH adjuster or oxidation-reduction potential adjuster in the pH-adjusted water production unit can be easily and finely controlled.

[0023] In the above invention (Inventions 1 to 8), it is preferable that the oxidation-reduction potential adjuster in the oxidation-reduction potential adjusting solvent production unit is a liquid, and the oxidation-reduction potential adjuster is injected into the non-aqueous solvent supply line by a pump or a pressurizing means using an inert gas in a sealed tank (Invention 9).

[0024] According to such an invention (Invention 9), the addition amount of the liquid oxidation-reduction potential adjuster in the oxidation-reduction potential adjusting solvent can be easily and finely controlled.

[0025] In the above invention (Inventions 1 to 8), it is preferable that the oxidation-reduction potential adjuster in the oxidation-reduction potential adjusting solvent production unit is a gas, and the oxidation-reduction potential adjuster is added by gas dissolution using a gas-permeable membrane module or a direct gas-liquid contact device using an ejector (Invention 10).

[0026] According to such an invention (Invention 10), the addition amount of the gaseous oxidation-reduction potential adjuster in the oxidation-reduction potential adjusting solvent can be easily and finely controlled.

[0027] In the above invention (Inventions 1 to 10), it is preferable to have a mechanism for removing dissolved oxygen in the pH-adjusted water (Invention 11).

[0028] According to such an invention (Invention 11), it is possible to suppress fluctuations in the pH or oxidation-reduction potential of the pH-adjusted water or the pH-adjusted water due to the influence of dissolved oxygen, and to produce the desired pH-adjusted water.

[0029] In the above inventions (Inventions 1 to 11), it is preferable to provide a purge mechanism for an inert gas in the first storage tank (Invention 12).

[0030] According to such an invention (Invention 12), it is possible to suppress the dissolution of oxygen, carbon dioxide, etc. during the storage of pH and redox potential adjustment in the first storage tank, and to suppress fluctuations in the pH and redox potential of the pH-adjusted water.

[0031] In the above inventions (Inventions 1 to 12), it is preferable that the pH of the pH-adjusted water is 9 or more and 13 or less, the redox potential is -0.4 V or more and 0.4 V or less, and the redox potential of the redox potential adjustment solvent is 0 V or more and 1.7 V or less (Invention 13).

[0032] According to such an invention (Invention 13), for a redox potential adjustment solvent with such a redox potential, chromium group elements such as molybdenum are likely to become non-conductive, making it difficult to dissolve, so the dissolution rate of molybdenum can be suppressed low. On the other hand, for pH-adjusted water with such pH and redox potential, regardless of the difference in wiring width, as a constant metal loss, extremely fine etching treatment with a metal loss of, for example, 10 nm can be achieved in a short treatment time.

[0033] In the above inventions (Inventions 1 to 13), it is preferable to use the pH-adjusted water and the redox potential adjustment solvent in the step of cleaning or dissolving the surface of a semiconductor material where chromium group elements are exposed (Invention 14).

[0034] According to such an invention (Invention 14), by alternately cleaning with preparation water having a pH and redox potential capable of suppressing the dissolution of chromium group elements such as molybdenum and a non-aqueous solvent having a different redox potential capable of finely adjusting the dissolution of chromium group elements, regardless of the difference in wiring width, as a constant metal loss, extremely fine etching treatment with a metal loss of, for example, 10 nm can be achieved in a short treatment time.

[0035] Second, the present invention provides a method for treating a semiconductor material, comprising: a first step of producing a redox potential-adjusted solvent by adding a redox potential adjuster to a non-aqueous solvent so as to obtain a predetermined redox potential, and treating the surface of the semiconductor material with the redox potential-adjusted solvent; and a second step of producing pH-adjusted water by adding a pH adjuster to ultrapure water, and treating the surface of the semiconductor material with the pH-adjusted water (Invention 15).

[0036] According to such an invention (Invention 15), by alternately treating with a redox potential-adjusted solvent capable of suppressing the dissolution of chromium group elements such as molybdenum first and pH-adjusted water capable of finely adjusting the dissolution of chromium group elements, stable ultra-fine etching treatment can be achieved as a constant metal loss regardless of the difference in wiring width.

Effects of the Invention

[0037] According to the process solution supply device for semiconductor manufacturing of the present invention, since washing can be performed alternately with a redox potential-adjusted solvent and pH-adjusted water, by alternately treating with a redox potential-adjusted solvent capable of suppressing the dissolution of chromium group elements such as molybdenum first and different pH-adjusted water capable of finely adjusting the dissolution of chromium group elements, ultra-fine etching treatment can be achieved in a short treatment time as a constant metal loss regardless of the difference in wiring width.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0039] Hereinafter, the process solution supply device for semiconductor manufacturing according to the present invention will be described in detail with reference to the accompanying drawings.

[0040] 〔Process Solution Supply Device for Semiconductor Manufacturing〕 FIG. 1 shows a process solution supply device for semiconductor manufacturing according to an embodiment of the present invention. In FIG. 1, the process solution supply device 1 for semiconductor manufacturing includes a pH-adjusted water production unit 2 and a redox potential-adjusted solvent production unit 3.

[0041] (pH-adjusted Water Production Unit 2) The pH-adjusted water production unit 2 is provided with a platinum group metal-supported resin column 22 as a hydrogen peroxide removal mechanism in the supply line 21 of ultrapure water W. A pH-adjusting agent injection line 23A equipped with a liquid supply mechanism (liquid supply pump) 23B communicating with a pH-adjusting agent tank 23 is connected to this supply line 21. In this embodiment, a redox potential-adjusting agent injection line 24A equipped with a liquid supply mechanism (liquid supply pump) 24B communicating with a first redox potential-adjusting agent tank 24 further joins. A first storage tank 25 for storing pH-adjusted water is provided downstream of the redox potential-adjusting agent injection line 24B. This first storage tank 25 is purged with an inert gas (IG) in this embodiment. And the supply line 21 extends from this first storage tank 25 to the use point UP. Note that 26 and 27 are a first on-off valve and a second on-off valve, respectively.

[0042] And in this embodiment, on the downstream side of the pH-adjusting agent injection line 23A and the redox potential-adjusting agent injection line 24A of the supply line 21, a pH meter as pH measurement means which is a first water quality monitoring mechanism (not shown) and an ORP meter as redox potential measurement means which is a second water quality monitoring mechanism and other adjusted water quality monitoring mechanisms are provided. These pH meters and ORP meters are connected to a control device such as a personal computer. And this control device can control the pH-adjusting agent injection amount and the redox potential-adjusting agent injection amount based on the measured values of these pH meters and ORP meters.

[0043] <Ultrapure water> In this embodiment, the ultrapure water W used as raw water preferably has, for example, a resistivity of 18.1 MΩ·cm or more, 1000 particles / L or less with a particle size of 50 nm or more, 1 viable bacterium / L or less, TOC (Total Organic Carbon) of 1 μg / L or less, total silicon of 0.1 μg / L or less, metals of 1 ng / L or less, ions of 10 ng / L or less, hydrogen peroxide of 30 μg / L or less, and a water temperature of 25±2°C.

[0044] <Hydrogen peroxide removal mechanism> In this embodiment, a platinum group metal-supported resin column 22 is used as the hydrogen peroxide removal mechanism.

[0045] (Platinum group metal) In this embodiment, examples of the platinum group metal supported on the platinum group metal-supported resin used in the platinum group metal-supported resin column 22 include ruthenium, rhodium, palladium, osmium, iridium, and platinum. These platinum group metals can be used individually, in combinations of two or more, as alloys of two or more, or as purified products of naturally occurring mixtures without separating them into individual components. Among these, platinum, palladium, platinum / palladium alloys alone or mixtures of two or more of these are preferably used because of their strong catalytic activity. Also, nanoparticles of these metals can be particularly preferably used.

[0046] (Support resin) In the platinum group metal-supported resin column 22, an ion exchange resin can be used as the support resin for supporting the platinum group metal. Among these, an anion exchange resin can be particularly preferably used. Since platinum group metals are negatively charged, they are stably supported on the anion exchange resin and are difficult to peel off. The exchange group of the anion exchange resin is preferably in the OH form. The OH form anion exchange resin makes the resin surface alkaline and promotes the decomposition of hydrogen peroxide.

[0047] <pH adjuster injection device> In this embodiment, there is no particular limitation on the pH adjuster injection device, and a general drug injection device can be used. When the pH adjuster is a liquid, a pump such as a diaphragm pump can be used. It is desirable to provide a mechanism in the pH adjuster tank 23 to purge with an inert gas or remove dissolved oxygen in the pH adjuster liquid in the tank using a degassing membrane. Further, a pressure pump in which a pH adjuster or a redox potential adjuster is placed in a sealed container together with an inert gas such as N2 gas and these agents are extruded by the pressure of the inert gas can also be preferably used. Furthermore, when the pH adjuster is a gas, a direct gas-liquid contact device such as a gas permeable membrane module or an ejector can be used.

[0048] <pH adjuster> In this embodiment, there is no particular limitation on the pH adjuster injected from the pH adjuster tank 23. When adjusting to less than pH 7, liquids such as citric acid, formic acid, hydrochloric acid, or gases such as CO2 can be used, but in this embodiment, a liquid is used. When adjusting to pH 7 or higher, ammonia, sodium hydroxide, potassium hydroxide, TMAH, or the like can be used. When using the pH-adjusted water as the cleaning water for a wafer on which a chromium group element such as molybdenum is exposed, it is preferably made alkaline. However, an alkali metal solution such as sodium hydroxide is not suitable because it contains metal components. Therefore, in this embodiment, it is most preferable to use ammonia, citric acid, or the like.

[0049] <Redox potential adjuster injection device> In this embodiment, there is no particular limitation on the redox potential regulator injection device, and a general drug injection device can be used. When the redox potential regulator is a liquid, a pump such as a diaphragm pump can be used. It is desirable to provide a mechanism in the tanks 24, 32 of the redox potential regulator to purge with an inert gas or remove dissolved oxygen in the pH regulator liquid in the tank using a degassing membrane. Also, a pressure-type pump that places the redox potential regulator in a sealed container together with an inert gas such as N2 gas and extrudes these agents by the pressure of the inert gas can be preferably used. Further, when the redox potential regulator is a gas, a direct gas-liquid contact device such as a gas permeable membrane module or an ejector can be used.

[0050] <Redox potential regulator> In this embodiment, there is no particular limitation on the redox potential regulator injected from the redox potential regulator tanks 24, 32. However, to adjust the redox potential to the positive side, a liquid such as hydrogen peroxide water or a gas such as ozone gas or oxygen gas can be used. Also, to adjust the redox potential to the negative side, a liquid such as oxalic acid or a gas such as hydrogen can be used. However, in this embodiment, a liquid is used. For example, when used as the cleaning water for a wafer where a transition metal such as molybdenum is exposed, it is most preferable to use hydrogen peroxide water because it is preferable to adjust the redox potential to be positive in order to suppress the elution of these materials.

[0051] (Redox potential adjustment solvent production unit 3) The oxidation-reduction potential adjusting solvent production unit 3 has a supply line 31 for isopropyl alcohol (IPA) S as a non-aqueous solvent, and a redox potential adjusting agent injection line 32A equipped with a liquid supply mechanism (liquid supply pump) 32B communicating with a second redox potential adjusting agent tank 32 merges into it. A second storage tank 33 for storing the redox potential adjusting solvent is provided downstream of this redox potential adjusting agent injection line 32A. In this embodiment, the second storage tank 33 is purged with an inert gas (IG). And a merging pipe 34 connected to the second storage tank 33 merges into the supply line 21 on the downstream side of the first on-off valve 26. Note that 35 is a third on-off valve.

[0052] And in this embodiment, a redox potential adjusting solvent monitoring mechanism such as an ORP meter as redox potential measuring means (not shown) is provided downstream of the redox potential adjusting agent injection line 32A of the supply line 31. This ORP meter is connected to a control device such as a personal computer. And this control device can control the injection amount of the redox potential adjusting agent based on the measured values of these ORP meters.

[0053] <Process Solution Supply Method for Semiconductor Manufacturing> A process solution supply method for semiconductor manufacturing using the manufacturing apparatus 1 of the process solution for semiconductor manufacturing of this embodiment having the configuration as described above will be described below.

[0054] (Method for Manufacturing pH-Adjusted Water) Since ultrapure water W as raw water generally contains hydrogen peroxide at a level of several tens of ppb, it is necessary to remove the hydrogen peroxide in the ultrapure water W in advance in order to accurately control the oxidation-reduction potential of the adjusted water. Therefore, first, ultrapure water W is supplied from the supply line 21 to the platinum group metal-supported resin column 22. In this platinum group metal-supported resin column 22, the hydrogen peroxide in the ultrapure water W is decomposed and removed by the catalytic action of the platinum group metal, that is, it functions as a hydrogen peroxide removal mechanism.

[0055] Then, in the supply line 21, a pH adjuster is injected from the pH adjuster tank 23. The addition of this pH adjuster may be appropriately set according to the desired pH, the flow rate of the ultrapure water W in the supply line 21, and the concentration of the pH adjuster. For example, when making it alkaline during the cleaning of a semiconductor having fine lines of a transition metal, an amount that makes the pH of the cleaning liquid fall within the range of 9 to 13 may be added. In the case of making it acidic, for example, an amount that makes the pH of the cleaning liquid fall within the range of 0 to 3.5 may be added.

[0056] Next, a redox potential adjuster is injected from the redox potential adjuster tank 24. The addition of this redox potential adjuster is appropriately set according to the desired redox potential, the flow rate of the ultrapure water W in the supply line 21, and the concentration of the redox potential adjuster. For example, for the cleaning of a semiconductor having fine lines of a transition metal, an amount that makes the redox potential of the conditioning water fall within the range of -0.4 V or more and 0.4 V or less may be added. Thereby, in the present embodiment, the pH-adjusted water becomes pH·redox potential-adjusted water W1.

[0057] After producing the pH·redox potential-adjusted water W1 in this way, it is stored in the first storage tank 25. Since this first storage tank 25 is purged with an inert gas (IG), while storing the obtained pH·redox potential-adjusted water W1, it is possible to prevent oxygen and carbon dioxide gas from dissolving in the pH·redox potential-adjusted water W1 and causing fluctuations in pH and redox potential. At this time, based on the measurement results of a pH meter and an ORP meter (not shown), by controlling the addition amount of the pH adjuster from the pH adjuster tank 23 and the addition amount of the redox potential adjuster from the redox potential adjuster tank 24 with a control device, it is possible to stably produce and supply the pH·redox potential-adjusted water W1 with the desired pH and redox potential.

[0058] (Method for producing a redox potential adjusting solvent) On one hand, in the supply line 31, isopropyl alcohol (IPA) S as a non-aqueous solvent is supplied, and a redox potential regulator is injected from the redox potential regulator tank 32 into this non-aqueous solvent S. The addition of this redox potential regulator may be appropriately set according to the desired redox potential, the type and flow rate of the non-aqueous solvent S, and the concentration of the redox potential regulator. For example, for the cleaning of a semiconductor having fine lines of transition metals, an amount may be added such that the redox potential of the redox potential adjusting solvent S1 ranges from 0 to 1.7V.

[0059] After manufacturing the redox potential adjusting solvent S1 in this way, it is stored in the second storage tank 33. Since this second storage tank 33 is purged with an inert gas (IG), during the storage of the obtained redox potential adjusting solvent S1, it is possible to prevent oxygen and carbon dioxide gas from dissolving in the redox potential adjusting solvent S1 and causing fluctuations in the redox potential. At this time, based on the measurement results of an ORP meter (not shown), by controlling the addition amount of the redox potential regulator from the redox potential regulator tank 32 with a control device, it is possible to stably manufacture and supply the pH·redox potential adjusting water W1 with the desired redox potential.

[0060] (Method for Supplying pH Adjusting Water and Redox Potential Adjusting Solvent) Then, the pH·redox potential adjusting water W1 manufactured in this way can be sent to the use point UP by opening the first on-off valve 26 and the second on-off valve 27 and closing the third on-off valve 35. Also, by closing the first on-off valve 26 and opening the second on-off valve 27 and the third on-off valve 35, the redox potential adjusting solvent S1 can be sent to the use point UP. In this way, the pH·redox potential adjusting water W1 and the redox potential adjusting solvent S1 can be alternately supplied to the use point UP.

[0061] (Supply Example of pH Adjusting Water and Redox Potential Adjusting Solvent) Hereinafter, a case where ultra-fine etching treatment of semiconductor wiring using molybdenum, which is a chromium group element, is performed with the pH·redox potential adjusting water W1 and the redox potential adjusting solvent S1 as described above will be described as an example.

[0062] In the ultra-fine etching of a wiring made of molybdenum, a technique called digital etching is used. This is a technique that repeatedly oxidizes the metal surface and dissolves the oxide film, gradually dissolving the metal. When ultra-fine etching molybdenum as a transition metal by digital etching, in the first step, an oxide film is formed on the molybdenum surface without dissolving the molybdenum, and in the second step, it is necessary to dissolve only the metal oxide film formed in the first step without dissolving the molybdenum.

[0063] According to the Pourbaix diagram showing which chemical species of a metal are the most stable in an aqueous solution under certain [potential-pH] conditions, it can be seen that chromium group elements, especially molybdenum, dissolve under alkaline conditions regardless of the difference in the pH and redox potential of the aqueous solution. On the other hand, under acidic conditions, it can be seen that the behaviors such as dissolution and passivation differ depending on the difference in the pH and redox potential of the aqueous solution. Also, from the XPS analysis results of the surface of a wafer with a molybdenum film, it was found that the molybdenum film is composed of MoO3, MoO2, and metallic Mo. However, from the immersion test of a wafer with a molybdenum film in which the pH and hydrogen peroxide concentration were varied, it was confirmed that MoO3, which is a molybdenum oxide, is dissolved by H2O, and the dissolution rate is faster as the pH is higher. Also, regardless of the pH of the treatment solution, the molybdenum dissolution rate increases as the hydrogen peroxide concentration increases, and it was also confirmed that the molybdenum dissolution rate varies depending on the pH of the treatment solution when the hydrogen peroxide concentrations are the same. Therefore, in order to oxidize the surface while preventing molybdenum dissolution in the first step of digital etching, it is necessary to use a non-aqueous solvent having oxidizing power or a solution with the water content reduced as much as possible to generate MoO3 on the molybdenum film surface.

[0064] On the other hand, in the second step, it is necessary to remove only the MoO3 generated in the first step. As described above, MoO3 dissolves in H2O, and the dissolution rate increases as the pH increases. Therefore, considering the throughput of the manufacturing process, it is particularly preferable to use an alkaline aqueous solution. At this time, if some kind of oxidizing agent is contained in the treatment liquid, oxidation of the molybdenum surface occurs simultaneously with molybdenum dissolution, changing the amount of molybdenum dissolved and leading to the occurrence of pattern loading. Therefore, the alkaline aqueous solution used in the second step needs to be one from which the oxidizing agent has been removed to the utmost extent.

[0065] As described above, in order to perform ultra - fine etching of a predetermined amount of chromium group elements (molybdenum) within a predetermined time while suppressing the occurrence of pattern loading, it is necessary to alternately supply a redox potential - adjusted solvent adjusted to a redox potential and water content at which dissolution of chromium group elements (especially molybdenum) is least likely to occur, and a pH - adjusted water with its pH adjusted and, if necessary, its redox potential adjusted so as to more quickly remove chromium group (molybdenum) oxides and simultaneously not generate pattern loading.

[0066] Specifically, in view of the above, in order to perform ultra - fine etching of a predetermined amount of molybdenum within a predetermined time while suppressing the occurrence of pattern loading, an aqueous hydrogen peroxide solution as a redox potential adjuster is added to IPA to adjust a non - aqueous solvent with a redox potential of 0 V or more and 1.7 V or less, that is, a redox potential - adjusted solvent S1. At this time, the first on - off valve 26 of the supply line 21 is closed, and the third on - off valve 35 of the confluence pipe 34 is opened so that the confluence pipe 34 communicates with the use point UP. Then, the redox potential - adjusted solvent S1 is supplied from the supply line 31 to the use point UP to perform the cleaning of the first step. Thereby, an oxide film is formed on the molybdenum surface without dissolving the molybdenum.

[0067] Next, molybdenum is etched in extremely small amounts within a predetermined time. At this time, in order to accelerate the removal rate of the molybdenum oxide film, aqueous ammonia as a pH adjuster and hydrogen peroxide water as a redox potential adjuster are added to ultrapure water W to adjust the pH·redox potential-adjusted water W1 so that the pH ranges from 9 to 13 and the redox potential ranges from 0 to 0.4V. Then, the third on-off valve 35 of the confluence pipe 34 is closed to stop the supply of the redox potential-adjusted solvent S1, and the first on-off valve 26 is opened to supply the pH·redox potential-adjusted water W1 from the supply line 21 to the use point UP to perform the cleaning in the second step. Thereby, the molybdenum oxide film can be etched extremely minutely.

[0068] In this way, the extremely minute etching of the wiring of the semiconductor having the wiring made of molybdenum can be efficiently performed.

[0069] As described above, the process solution supply device for semiconductor manufacturing according to the present invention has been described with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the present embodiment, the pH·redox potential-adjusted water W1 is used, but only a pH adjuster may be added without adjusting the redox potential to obtain pH-adjusted water. Also, depending on the process, the redox potential may be adjusted in the negative direction by dissolving hydrogen gas as a redox potential adjuster.

Example

[0070] The present invention will be described in more detail with the following specific examples.

[0071] [Example 1] A 300 mmΦ Mo blanket wafer was cut into 30 mm squares to obtain test pieces. After sequentially immersing these test pieces in Liquid 1 and Liquid 2 under the processing conditions shown below, the molybdenum (Mo) concentration in the processing liquid was analyzed by ICP-MS, and the film thickness of the dissolved Mo was derived. The total amount of the dissolved film thickness of Mo is shown in FIG. 1, and the dissolved film thickness of Mo for each process is shown in FIG. 2.

[0072] ·Processing method: Digital etch ·Processing liquid 1: IPA + H2O2 (0, 1, 10, 100, 1000 ppm) Liquid 2: Ammonia water (ammonia concentration: 100 ppm) ·Processing time: Liquid 1: 1 minute, Liquid 2: 2 minutes ·Number of repetitions of digital etching: 5 times ·Processing temperature: Room temperature ·Analysis method: ICP-MS (analysis of the film thickness of the Mo dissolution film after processing)

[0073] In Example 1, the Mo dissolution film thickness of the present invention was verified. The dissolution of Mo occurs through reactions as shown in equations (1) to (3). Mo + 2H2O → MoO2 + 4H + + 4e - ···(1) MoO2 + H2O → MoO3 + 2H + + 2e - ···(2) MoO3 + H2O → HMoO4 + H + ···(3)

[0074] In this way, in the IPA + H2O2 of Liquid 1, Mo metal and MoO2 are oxidized to form MoO3, but it is considered that the dissolution of MoO3 is unlikely to occur. On the other hand, in Liquid 2, only MoO3 dissolves, and it is considered that the dissolution and oxidation of Mo metal and MoO2 do not occur.

[0075] As is clear from FIGS. 1 and 2 showing the Mo dissolution film thickness when using only IPA (H2O2: 0 ppm) as the first liquid and 1, 10, 100, 1000 ppm in an aqueous NH4OH solution, and using a 100 ppm NH4OH solution as the second liquid, when treated with only IPA, since it is difficult to form a Mo oxide film, it can be seen that almost no dissolution of Mo occurs in the subsequent NH4OH solution. On the other hand, when H2O2 is added to IPA, when the addition amount is 100 ppm or less, almost no dissolution of Mo occurs in the IPA + H2O2 solvent, which is similar to the case of using only IPA (without adding H2O2), and the amount of Mo dissolved in the aqueous NH4OH solution in the second step increases in proportion to the H2O2 concentration added to IPA. From this, when the H2O2 concentration in IPA is 100 ppm or less, it is considered that the thickness of the Mo oxide film formed in the IPA + H2O2 solvent becomes thicker in proportion to the H2O2 concentration. On the other hand, when the addition amount of H2O2 to IPA is 1000 ppm, not only in the aqueous NH4OH solution but also the Mo dissolution film thickness in the IPA + H2O2 solvent increases. This is considered that while the H2O2 concentration in the IPA + H2O2 solvent becomes high and it becomes easier to form a Mo oxide film, the water content of IPA increases due to the increase in H2O derived from H2O2, and Mo oxide film dissolution also occurs in the IPA + H2O2 solvent. Therefore, if the H2O2 concentration in the IPA + H2O2 solvent is 100 ppm or less, it is possible to oxidize the Mo surface without causing Mo dissolution in the first liquid, and in the second liquid, only the Mo oxide film formed in the first liquid can be dissolved, so it is considered that pattern loading does not occur.

[0076] [Comparative Example 1] As a conventional example, in Example 1, the treatment liquid was changed to 1 liquid: O3 (ozone) dissolved water (ozone concentration 20 ppm), 2 liquid: diluted hydrogen peroxide water (hydrogen peroxide concentration: 0.05%), and after immersing the test piece in the 1 liquid and the 2 liquid for 75 seconds each, the molybdenum (Mo) concentration in the treatment liquid was analyzed by ICP-MS, and the film thickness of the dissolved Mo was derived. The results are shown in FIG. 3.

[0077] As is clear from FIG. 3, when the test piece is immersed in the O3-dissolved water, the Mo dissolution film thickness increases in proportion to the immersion time. Therefore, it is considered that Mo oxidation and Mo oxide film dissolution occur simultaneously in the O3-dissolved water. For this reason, only Mo oxidation is carried out in one liquid, and it is dissociated from the purpose of digital etching for dissolving the Mo oxide film in two liquids. In addition, since Mo oxidation and Mo oxide film dissolution occur simultaneously in one liquid, it can be seen that the Mo film thickness dissolved in each treatment step and the Mo oxide film thickness generated become uneven, resulting in pattern loading.

Explanation of symbols

[0078] 1 Process solution supply device for semiconductor manufacturing 2 pH-adjusted water production section 21 Supply line 22 Platinum group metal-supported resin column (hydrogen peroxide removal mechanism) 23 pH adjuster tank 23A pH adjuster injection line 23B Liquid supply mechanism (liquid supply pump) 24 First oxidation-reduction potential adjuster tank 24A Oxidation-reduction potential adjuster injection line 24B Liquid supply mechanism (liquid supply pump) 25 First storage tank 26 First on-off valve 27 Second on-off valve 3 Oxidation-reduction potential adjustment solvent production section 31 Supply line 32 Second oxidation-reduction potential adjuster tank 32A Oxidation-reduction potential adjuster injection line 32B Liquid supply mechanism (liquid supply pump) 33 Second storage tank 34 Confluence pipe 35 Third on-off valve W Ultrapure water W1 pH·oxidation-reduction potential adjusted water (pH-adjusted water) S Isopropyl alcohol (IPA) (non-aqueous solvent) S1 Oxidation-reduction potential adjustment solvent UP Use point

Claims

1. A pH-adjusted water production unit comprising an ultrapure water supply line, a hydrogen peroxide removal mechanism disposed in the ultrapure water supply line, a pH adjustment mechanism for adding a pH adjuster to the ultrapure water from which hydrogen peroxide has been removed so as to achieve a predetermined pH, a first water quality monitoring mechanism for monitoring the pH of the pH-adjusted water whose pH has been adjusted, a control mechanism for controlling the addition amount of the pH adjuster by the pH adjustment mechanism so as to achieve a desired pH based on the water quality measured by the first water quality monitoring mechanism, and a first storage tank for storing the produced pH-adjusted water. A redox potential-adjusted solvent production unit comprising a non-aqueous solvent supply line, a redox potential adjustment mechanism for adding a redox potential adjuster to isopropyl alcohol flowing through the non-aqueous solvent supply line so as to achieve a predetermined redox potential, and a second storage tank for storing the produced redox potential-adjusted solvent. And supply means for supplying the pH-adjusted water stored in the first storage tank and the redox potential-adjusted solvent stored in the second storage tank, respectively. A process solution supply device for semiconductor manufacturing, having the above components.

2. A redox potential adjustment mechanism for adding a redox potential adjuster so as to achieve a predetermined redox potential, a second water quality monitoring mechanism for monitoring the redox potential of the adjusted water whose redox potential has been adjusted, and a control mechanism for controlling the addition amount of the redox potential adjuster by the redox potential adjustment mechanism so as to achieve a desired redox potential based on the water quality measured by the second water quality monitoring mechanism, are provided downstream of the hydrogen peroxide removal mechanism in the ultrapure water supply line. The process solution supply device for semiconductor manufacturing according to Claim 1.

3. The process solution supply device for semiconductor manufacturing according to Claim 1 or 2, wherein the supply means can alternately supply the pH-adjusted water stored in the first storage tank and the redox potential-adjusted solvent stored in the second storage tank.

4. The process solution supply device for semiconductor manufacturing according to any one of Claims 1 to 3, wherein the pH adjuster in the pH-adjusted water production unit is one or more of ammonia, sodium hydroxide, potassium hydroxide, TMAH, and choline.

5. The process solution supply device for semiconductor manufacturing according to Claim 2, wherein the redox potential adjuster in the pH-adjusted water production unit is one or more of hydrogen gas, oxalic acid, hydrogen sulfide, and potassium iodide.

6. The semiconductor manufacturing process solution supply device according to any one of claims 1 to 5, wherein the redox potential adjusting agent in the redox potential adjusting solvent manufacturing unit is one or more of hydrogen peroxide, ozone gas, oxygen gas, and nitric acid.

7. The semiconductor manufacturing process solution supply device according to claim 2 or 4, wherein the pH adjusting agent or the redox potential adjusting agent in the pH adjusting water manufacturing unit is a liquid, and the pH adjusting agent or the redox potential adjusting agent is injected into the ultrapure water supply line by a pump or a pressurizing means using an inert gas in a sealed tank.

8. The semiconductor manufacturing process solution supply device according to claim 2 or 4, wherein the pH adjusting agent or the redox potential adjusting agent in the pH adjusting water manufacturing unit is a gas, and the pH adjusting agent or the redox potential adjusting agent is added by gas dissolution using a gas permeable membrane module or a direct gas-liquid contact device using an ejector.

9. The semiconductor manufacturing process solution supply device according to any one of claims 1 to 8, wherein the redox potential adjusting agent in the redox potential adjusting solvent manufacturing unit is a liquid, and the redox potential adjusting agent is injected into the non-aqueous solvent supply line by a pump or a pressurizing means using an inert gas in a sealed tank.

10. The semiconductor manufacturing process solution supply device according to any one of claims 1 to 8, wherein the redox potential adjusting agent in the redox potential adjusting solvent manufacturing unit is a gas, and the redox potential adjusting agent is added by gas dissolution using a gas permeable membrane module or a direct gas-liquid contact device using an ejector.

11. The semiconductor manufacturing process solution supply device according to any one of claims 1 to 10, having a mechanism for removing dissolved oxygen in the pH adjusted water.

12. The semiconductor manufacturing process solution supply device according to any one of claims 1 to 11, comprising a purge mechanism for an inert gas in the first storage tank.

13. The semiconductor manufacturing process solution supply device according to any one of claims 1 to 12, wherein the pH of the pH adjusted water is 9 or more and 13 or less, the redox potential is -0.4 V or more and 0.4 V or less, and the redox potential of the redox potential adjusting solvent is 0 V or more and 1.7 V or less.

14. The semiconductor manufacturing process solution supply device according to any one of claims 1 to 13, wherein the pH adjusted water and the redox potential adjusting solvent are used in a step of cleaning or dissolving the surface of a semiconductor material on which a chromium group element is exposed.

15. A first step of producing a redox potential-adjusted solvent by adding a redox potential-adjusting agent to isopropyl alcohol so as to obtain a predetermined redox potential, and treating the surface of a semiconductor material with this redox potential-adjusted solvent; A second step of producing pH-adjusted water by adding a pH-adjusting agent to ultrapure water, and treating the surface of a semiconductor material with this pH-adjusted water; A method for treating a semiconductor material, comprising the above steps.

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