JP2004241683A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent ionized amines from flowing into ultrapure water in a step of manufacturing the ultrapure water for use in a step of manufacturing semiconductor device. <P>SOLUTION: When an UF (ultrafilteration) module UFM (UF module) to be newly input is cleaned, an aqueous solution of acid is first supplied from acids supply equipment ASPE so that higher amines in the UF module UFM react with the aqueous solution of acid to form an aqueous higher amine salt. Next, after the aqueous solution of acid is discharged, pure water is supplied from a pure water supply equipment PWPE to clean the UF module UFM therewith. The treatment using the aqueous solution of acid and the pure water cleaning are repeated until an amine concentration in the cleaning solution (pure water) discharged from the UF module UFM during the pure water cleaning becomes a prescribed value or smaller. A gas is supplied from a gas supply equipment GPE between the treatment using the aqueous solution of acid and the pure water cleaning to be subject to gas blow. Consequently, cleaned residue in the UF module UFM is reduced. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor device manufacturing technique, and more particularly to a technique that is effective when applied to a method for improving the quality of pure water used in a semiconductor device manufacturing process.
[0002]
[Prior art]
Since the manufacture of semiconductor devices is microfabrication of integrated circuits, it is necessary to remove impurities (contamination) present on the surface and interface of a semiconductor wafer (hereinafter simply abbreviated as “wafer”) by washing or the like to keep the semiconductor wafer clean. Can be Foreign matter on the wafer surface may cause disconnection or short circuit of the wiring. Particularly, since heavy metal components greatly affect the electrical characteristics of the device, it is required to reliably remove them.
[0003]
By the way, pure water is used for washing a chemical solution after a cleaning process using a chemical solution or after a wet etching process to obtain a clean wafer surface, or is used in a process of preparing a chemical solution used for the cleaning process or the wet etching process. . The pure water used in these steps is obtained by using fine particles, organic substances, and polymer ions in raw water using river water or groundwater (including well water), for example, using an RO (Reverse Osmosis) membrane. After removing the other ions in the raw water using the RO device and the ion-exchange resin, other fine particles and viable bacteria in the raw water that could not be removed by the RO device and the ion-exchange resin were removed by the UF device ( It is manufactured by removing with an ultrafiltration device (Ultrafiltration Equipment) (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-4-78483
[0005]
[Problems to be solved by the invention]
The present inventors are studying the construction of a system for obtaining highly pure water (hereinafter, referred to as ultrapure water) used in a semiconductor device manufacturing process. In the meantime, the present inventor has found that the following problems occur.
[0006]
That is, the UF device is used in the final step of the production process of ultrapure water. Further, the UF device has a filter in which a plurality of tubular hollow fiber membranes are bundled with an adhesive made of an epoxy resin or the like to form a module. It needs to be replaced with something. The adhesive that bundles the hollow fiber membranes contains amines, and some of the amines are ionized. After replacing the filter, the ionized amines are made hydrophilic by passing water through a UF device, and are dissolved in ultrapure water. When this ultrapure water containing ionized amines is used in a wafer cleaning step immediately before forming a gate insulating film of, for example, a MISFET (Metal Insulator Semiconductor Effect Transistor), the ionized amines form Si ( Since silicon is etched, irregularities are formed at the interface between the gate insulating film and the wafer after the gate insulating film is formed. The MISFET formed in such a situation has a problem that a characteristic failure occurs because the current between the source and the drain hardly flows.
[0007]
Therefore, in order to prevent the above-mentioned amines from being eluted into ultrapure water, the inventor distributed pure water to the UF apparatus after manufacturing the UF apparatus and before actually using the UF apparatus for producing ultrapure water. Then, a means for discharging the amine in the UF device to the outside of the UF device was examined.
[0008]
However, since many amines have low solubility in pure water, the flow time of pure water and the amount of pure water used to discharge the amine in the UF device out of the UF device increase. There's a problem. Therefore, if the process of distributing the pure water to the UF device is also included in the manufacturing process of the UF device, there is a problem that the manufacturing cost of the UF device increases.
[0009]
An object of the present invention is to provide a technique for preventing ionized amine from flowing into ultrapure water in a step of producing ultrapure water used in a semiconductor device manufacturing process.
[0010]
Another object of the present invention is to provide a technique capable of preventing an increase in the flow time of pure water to the UF device and the amount of pure water used for discharging amine in the UF device to the outside of the UF device. It is in.
[0011]
The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0012]
[Means for Solving the Problems]
The following is a brief description of an outline of typical inventions disclosed in the present application.
[0013]
That is, the present invention uses the secondary pure water produced by removing the particulate foreign matter in the primary pure water by passing the primary pure water through the ultrafiltration module, and uses the first pure water for the semiconductor wafer. Attaching the ultrafiltration module to a first cleaning system having a pure water supply unit and an acid aqueous solution supply unit with respect to the ultrafiltration module before the production of the secondary pure water. A step of introducing an acid aqueous solution from the acid aqueous solution supply means into the first cleaning system to fill the ultrafiltration module with the acid aqueous solution, and filling the ultrafiltration module with the acid aqueous solution Discharging the acid aqueous solution to the outside of the first cleaning system after leaving the apparatus for a predetermined time in the state where the acid solution has been discharged; and discharging the pure water supplier after discharging the acid aqueous solution to the outside of the first cleaning system. By circulating pure water to the first washing system from, it performs a cleaning process and a step of removing the acid solution remaining in said ultrafiltration module.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted.
[0015]
FIG. 1 is an explanatory diagram of a pure water (ultra pure water) production system for semiconductor production according to the present embodiment.
[0016]
As shown in FIG. 1, the pure water production system for semiconductor production according to the present embodiment first introduces primary pure water having a specific resistance of about 2 MΩ into a pure water tank TANK, and then supplies the primary pure water to a pure water pump PUMP. To the heat exchanger HEXC. Between the pure water tank TANK and the pure water pump PUMP, there is provided a filter FILT for removing foreign matter such as a piece of piping material or a piece of metal, and a pure water production system for semiconductor production according to the present embodiment. When the foreign matter is generated in the inside, the foreign matter is removed by the filter FILT, thereby making it possible to prevent the foreign matter from entering the pure water pump PUMP. Further, a similar filter FILT may be provided between the pure water pump PUMP and the heat exchanger HEXC.
[0017]
Subsequently, the primary pure water is sent to the low-pressure UV oxidizer UVOX while the temperature is kept constant by the heat exchanger HEXC. The primary pure water is subjected to sterilization treatment by ultraviolet irradiation and oxidation treatment of organic matter by the low-pressure UV oxidation device UVOX, and then passes through the ion exchange resin IEXC to thereby contain a small amount of organic matter ions and metal ions contained therein. Etc. are removed. Thereafter, the UF unit UFU removes the fine particles that could not be removed by the ion exchange resin IEXC and the fine particles generated by the crushing of the ion exchange resin IEXC, so that ultrapure water with a high specific resistance of about 18.1 MΩ ( Secondary pure water). At this time, about 10% of the primary pure water flowing into the UF unit UFU is used for discarding the fine particles removed by the UF unit UFU. The ultrapure water thus produced is sent from the UF unit UFU to the semiconductor production line USE.
[0018]
Part of the ultrapure water used in the semiconductor manufacturing line USE is drained, and the rest is circulated to the pure water tank TANK for reuse. In the pure water production system for semiconductor production according to the present embodiment, in the path in which the ultrapure water is circulated from the semiconductor production line USE to the pure water tank TANK, immediately before the pure water tank TANK, fragments of pipe material or metal. A filter FLT2 for removing foreign matters such as pieces may be provided. That is, even when foreign matter such as a piece of piping material or a metal piece is generated in a pipe in which ultrapure water is circulated from the semiconductor manufacturing line USE to the pure water tank TANK, the foreign matter is transferred from the semiconductor manufacturing line USE to the pure water tank. It can be prevented from being mixed into ultrapure water circulated to TANK.
[0019]
As shown in FIG. 2, the UF unit UFU is formed from a plurality of UF modules UFM. As shown in FIGS. 3 and 4, the UF module UFM includes a plurality of capillary hollow fiber membranes TYM formed of, for example, a polysulfone membrane or a polyimide membrane in a housing KOT. The hollow fiber membrane TYM is formed by bonding both ends of the hollow fiber membrane TYM with an adhesive made of epoxy resin or the like, and further bonding the hollow fiber membrane TYM to the housing KOT with the adhesive. FIG. 4 is a sectional view taken along the line AA in FIG.
[0020]
Further, as shown in FIG. 5, since the hollow fiber membrane TYM is formed of a polysulfone membrane or a polyimide membrane, water, ionic molecules and small molecules can penetrate into the hollow fiber membrane TYM, However, polymers cannot penetrate into the interior. Further, in the housing KOT, ends of the plurality of hollow fiber membranes TYM are adhered to each other with an adhesive, and the hollow fiber membrane TYM is also adhered to the housing KOT. It is possible to use only primary pure water that has permeated into the fiber membrane TYM, that is, only ultrapure water in which the polymer has been removed from the primary pure water.
[0021]
By the way, the UF module UFM needs to be periodically replaced with a new one because of the life of the material. The adhesive that bundles the hollow fiber membranes TYM contains amines, and some of the amines are ionized. The ionized amines are made hydrophilic by passing water through a UF module UFM newly introduced by exchange, and are dissolved in ultrapure water. When the ultrapure water in which the ionized amines are dissolved is used in, for example, a wafer cleaning process immediately before forming a gate insulating film of a MISFET, the ionized amines etch Si forming the wafer. Therefore, there is a concern that irregularities may be formed at the interface between the gate insulating film and the wafer after the formation of the gate insulating film.
[0022]
Therefore, it is required that the new UF module UFM be washed before newly introduced into the UF unit UFU to remove amines contained in the adhesive. As a washing method, for example, a method in which pure water is passed through the UF module UFM to wash away amines can be considered. At this time, since the lower amines having about 1 to 5 carbon atoms are gaseous or liquid and have high solubility in pure water, the lower amines can be easily mixed with the pure water passed through the UF module UFM and easily mixed. It can be removed from the UF module UFM. On the other hand, higher amines having about 10 or more carbon atoms show general properties as amines, but are more difficult to polarize because they show stronger properties as long-chain hydrocarbons. Very low solubility in water. Therefore, there is a concern that higher amines cannot be removed from the UF module UFM in the cleaning method by passing pure water through the UF module UFM.
[0023]
Therefore, in the present embodiment, the UF module UFM to be newly introduced into the UF unit UFU is cleaned by using a UF module UFM cleaning facility (first cleaning system) as shown in FIG. This cleaning equipment will be described below.
[0024]
As shown in FIG. 6, the cleaning equipment for the UF module UFM of the present embodiment includes, for example, a pure water supply equipment (pure water supply means) PWPE for supplying pure water to the cleaning equipment, and a supply of an acid aqueous solution to the cleaning equipment. And a gas supply facility (gas supply means) GPE for supplying gas to the cleaning facility. Closing valves CV1 to CV7 and check valves RV1 to RV3 are disposed in a pipe connecting the pure water supply facility PWPE, the acid supply facility ASPE, the gas supply facility GPE, and the UF module UFM, and pure water and acid flowing through the pipe are provided. The flow rates of the aqueous solution and the gas can be controlled. Further, the pipes are provided with flow meters FM1 to FM3 for measuring the respective flow rates of pure water, acid aqueous solution and gas flowing in the pipe, and pressure gauges PG1 to PG3 for measuring the pressure. Further, filters FLT3 to FLT5 are arranged in the piping, and even if foreign matter flows into the piping, the foreign matter is removed by the filters FLT3 to FLT5 so that the foreign matter can be prevented from reaching the UF module UFM.
[0025]
Next, a method of cleaning the UF module UFM using the cleaning apparatus of the present embodiment shown in FIG. 6 will be described with reference to a flowchart including steps P1 to P8 shown in FIG.
[0026]
First, the cleaning equipment for the UF module UFM as shown in FIG. 6 is assembled, and a new UF module UFM is attached to the cleaning equipment (step P1).
[0027]
First, the closing valves CV2 and CV5 are closed, and then the closing valves CV3, CV4 and CV7 are opened. Then, an acid aqueous solution is supplied to the cleaning equipment from the acid supply equipment ASPE, and the UF module UFM is filled with the acid aqueous solution. Let it. Subsequently, the UF module UFM is left for a predetermined time while being filled with the acid aqueous solution, and the higher amine in the UF module UFM is reacted with the acid aqueous solution (step P2).
[0028]
The aqueous acid solution used at this time is an aqueous acid solution that can react with an amino group in a higher amine to form a water-soluble higher amine salt. In the present embodiment, a dilute hydrochloric acid (HCl) aqueous solution is exemplified. Can be. Here, FIG. 8 shows the concentration of the diluted hydrochloric acid aqueous solution and the residual amount of the higher amine in the UF module UFM after the supply of the diluted hydrochloric acid aqueous solution (the higher amine amount in the UF module UFM before the supply of the diluted hydrochloric acid aqueous solution to the UF module UFM is 100). %). As shown in FIG. 8, it can be seen that the higher the concentration, the easier the removal of the higher amine. However, if the concentration is too high, the hollow fiber membrane (see FIGS. 3 to 5) in the UF module UFM is removed. The hollow fiber membrane may be deteriorated to lower the mechanical strength and the filtration performance of the hollow fiber membrane. On the other hand, if the concentration of the dilute hydrochloric acid aqueous solution is too low, it is difficult to form a higher amine salt, and the efficiency of removing the higher amine in the UF module UFM may be reduced. The concentration of the diluted hydrochloric acid aqueous solution may be about 0.05M to 0.5M, preferably about 0.1M to 0.3M.
[0029]
At this time, for example, nitric acid (HNO ₃ ), Chloric acid (HClO ₃ ) Or perchloric acid (HClO ₄ The use of an oxidizing acid aqueous solution such as the aqueous solution of hydrochloric acid in place of the diluted hydrochloric acid aqueous solution is not preferred because the hollow fiber membrane (see FIGS. 3 to 5) in the UF module UFM may be oxidized and damaged. Further, even in the case of an acid aqueous solution capable of forming a higher amine salt, for example, sulfuric acid (H ₂ SO ₄ The non-volatile acid aqueous solution as described in (1) is preferable because it remains even after the cleaning of the UF module UFM, and the residue may become an impurity and be mixed into the pure water to lower the quality of the pure water. Absent.
[0030]
In addition, the time during which the inside of the UF module UFM is left filled with the acid aqueous solution is determined by the capacity of the UF module UFM and the concentration of the acid aqueous solution. In the present embodiment, the time of the UF module UFM is For example, when the capacity is 200 l to 300 l, the leaving time may be about 30 minutes.
[0031]
Next, after closing the closing valve CV7 and opening the closing valves CV5 and CV6, a predetermined gas (first gas) is supplied to the cleaning equipment from the gas supply equipment GPE, and the gas of the UF module UFM is blown (step P3). ). In the present embodiment, examples of the gas supplied from the gas supply facility GPE include an inert gas such as dry air, dry nitrogen, and a rare gas. By performing such gas blowing, the acid aqueous solution remaining in the process P2 remaining in the UF module UFM is removed.
[0032]
Next, after closing the closing valves CV3 and CV5 and opening the closing valves CV1, CV2 and CV7, pure water is supplied to the cleaning equipment from the pure water supply equipment PWPE to perform the pure water cleaning of the UF module UFM (step). P4). Thus, the acid aqueous solution and the higher amine salt remaining in the UF module UFM without being removed in the process P3 are removed. At this time, a part of the cleaning liquid (pure water) discharged from the UF module UFM is collected, and the amine concentration in the cleaning liquid is measured.
[0033]
Next, the same gas blow as in the step P3 is performed to remove the cleaning liquid remaining in the UF module UFM and used in the step P4 (step P5).
[0034]
Next, when the amine concentration in the cleaning solution measured in the step P4 is higher than a specified value, the above steps P2 to P5 are repeated until the amine concentration in the cleaning solution becomes equal to or lower than a specified value (first concentration). In the present embodiment, it can be exemplified that the specified value is set to about 10 ppt. As described above, by repeating the steps P2 to P5, the effect of cleaning the UF module UFM (the effect of removing amines contained in the UF module UFM) can be improved. On the other hand, when the amine concentration in the cleaning solution measured in the step P4 is equal to or lower than the specified value, the process proceeds to the final pure water cleaning step of the UF module UFM (step P6).
[0035]
Next, the UF module UFM in which the amine concentration in the cleaning liquid has become equal to or less than the specified value in the above-described process P6 is subjected to final pure water cleaning (process P7), and the cleaning process of the UF module UFM of the present embodiment is performed. Complete. In the above Steps P1 to P7, the explanation has been made focusing on the removal of higher amines. However, in Steps P1 to P7, since pure water is passed through the UF module UFM, lower amines should also be removed. Can be.
[0036]
According to the method of cleaning the UF module UFM of the present embodiment as described above, for example, the efficiency is higher than that of the means for removing amines contained in the UF module UFM only by passing pure water through the UF module UFM. Since the amines can be removed specifically, the time required for the cleaning treatment can be reduced. As a result, it is possible to reduce the amount of pure water used for the cleaning process of the UF module UFM. According to an experiment performed by the present inventors, it was found that the time required for the cleaning treatment can be reduced by about one fifth and the amount of pure water used can be reduced by about one third.
[0037]
Further, according to the method of cleaning the UF module UFM of the present embodiment, the amount of pure water used for the cleaning process of the UF module UFM can be reduced, and thus the cost of the pure water used for the cleaning process can be reduced. Can be reduced. Thus, the manufacturing cost of the semiconductor device according to the present embodiment can be reduced.
[0038]
Further, according to the method of cleaning the UF module UFM of the present embodiment of the present embodiment, the time required for the cleaning process of the UF module UFM can be shortened. When the UF module UFM in use in the pure water production system breaks down and needs to be replaced with a new UF module UFM, the time required for incorporating the new UF module UFM into the pure water production system for semiconductor production. Can be shortened. Therefore, it is possible to reduce the time required for restoring the pure water production system for semiconductor production whose operation has been stopped.
[0039]
Next, a manufacturing process of the semiconductor device of the present embodiment using the ultrapure water manufactured by the semiconductor pure water manufacturing system of the present embodiment described with reference to FIGS. 13 will be described.
[0040]
First, as shown in FIG. 9, a wafer 1 made of single crystal Si having a specific resistance of about 10 Ωcm is heat-treated at about 850 ° C., and a thin silicon oxide film (pad oxide film) having a thickness of about 10 nm is formed on its main surface. Form. Next, a silicon nitride film having a thickness of about 120 nm is deposited on the silicon oxide film by a CVD (Chemical Vapor Deposition) method, and then the silicon nitride film and the silicon oxide film in the element isolation region are subjected to dry etching using a photoresist film as a mask. Remove the membrane. The silicon oxide film is formed for the purpose of reducing stress applied to the substrate when densifying (baking) the silicon oxide film embedded in the element isolation trench in a later step. Further, since the silicon nitride film has a property of being hardly oxidized, it is used as a mask for preventing the oxidation of the substrate surface below (the active region).
[0041]
Subsequently, after removing the photoresist film, an element isolation groove 2 having a depth of about 350 nm is formed in the wafer 1 in the element isolation region by dry etching using a silicon nitride film as a mask. In order to remove the damaged layer generated on the inner wall, the wafer 1 is heat-treated at about 1000 ° C. to form a thin silicon oxide film having a thickness of about 10 nm on the inner wall of the groove.
[0042]
Subsequently, after depositing the silicon oxide film 3 on the wafer 1 by the CVD method, in order to improve the film quality of the silicon oxide film 3, the wafer 1 is heat-treated and the silicon oxide film 3 is densified (baked). . After that, the silicon oxide film 3 is polished by a chemical mechanical polishing (CMP) method using a silicon nitride film as a stopper, and is left inside the element isolation groove 2, whereby the element whose surface is flattened. Form an isolation region.
[0043]
Subsequently, after removing the silicon nitride film remaining on the active region of the wafer 1 by wet etching using hot phosphoric acid, B (boron) is ion-implanted into a region of the wafer 1 where an n-channel MISFET is to be formed. A p-type well 4 is formed. Next, an n-type well 5 is formed by ion-implanting P (phosphorus) into a region of the wafer 1 where a p-channel MISFET is to be formed.
[0044]
Next, the wafer 1 is subjected to a cleaning process (first wet process) using ultrapure water manufactured by the semiconductor pure water manufacturing system of the present embodiment described with reference to FIGS.
[0045]
At this time, if the ultrapure water contains amines, the silicon forming the wafer 1 is etched, so that there is a concern that irregularities may be formed in the active region on the main surface of the wafer 1. You. If a gate insulating film is formed in the active region in the subsequent steps under such a condition of unevenness, unevenness is also formed at the interface between the gate insulating film and the wafer 1, and the withstand voltage of the gate insulating film decreases. It is feared that it will. In addition, since the unevenness affects the shape of the thin film formed on the gate insulating film, the unevenness may be formed on the interface between the gate insulating film and the thin film serving as the gate electrode. There is a concern that the characteristics of the polymer may be deteriorated.
[0046]
On the other hand, according to the present embodiment, it is possible to effectively prevent amines from being mixed into the ultrapure water used for cleaning the wafer 1, so that the active region on the main surface of the wafer 1 has irregularities during the cleaning. Can be prevented from being formed. Thus, a decrease in the withstand voltage of the gate insulating film can be prevented. Also, it is possible to prevent the characteristics of the MISFET from being deteriorated.
[0047]
Subsequently, the gate insulating film 6 is formed on the surfaces of the p-type well 4 and the n-type well 5 by heat-treating the wafer 1.
[0048]
Next, as shown in FIG. 10, for example, a P-doped low-resistance polycrystalline silicon film, WSi _x A (tungsten silicide) film and a silicon oxide film are sequentially deposited from the lower layer. Subsequently, the silicon oxide film, WSi is formed by dry etching using a photoresist film (not shown) patterned by photolithography as a mask. _x By patterning the film, the polycrystalline silicon film and the gate insulating film 6, the WSi _x The gate electrode 7 made of a film and a polycrystalline silicon film can be formed.
[0049]
Subsequently, after removing the photoresist film, an n-type semiconductor region (source, drain) 8 is formed by ion-implanting P or As (arsenic) into the p-type well 4, and B is added to the n-type well 5. A p-type semiconductor region (source, drain) 9 is formed by ion implantation. Through the steps so far, the n-channel MISFET Qn is formed in the p-type well 4 and the p-channel MISFET Qp can be formed in the n-type well 5.
[0050]
Next, as shown in FIG. 11, an interlayer insulating film 11 is formed on the n-channel MISFET Qn and the p-channel MISFET Qp by depositing, for example, a silicon oxide film. Subsequently, the interlayer insulating film 11 is dry-etched using the photoresist film patterned by the photolithography technique as a mask, so that a contact hole 13 is formed above the n-type semiconductor region 8 and the p-type semiconductor region 9.
[0051]
Subsequently, after removing the photoresist film used for drilling the contact hole 13, for example, a titanium nitride film 14 is deposited on the wafer 1 including the inside of the contact hole 13 by a sputtering method. Next, a W (tungsten) film 15 is deposited on the wafer 1, and the contact holes 13 are filled with the W film 15. Thereafter, the titanium nitride film 14 and the W film 15 on the interlayer insulating film 11 other than the contact hole 13 are removed by, for example, a CMP method, and a plug 16 is formed.
[0052]
Next, as shown in FIG. 12, a Ti (titanium) film, an Al alloy film, and a titanium nitride film are sequentially deposited on the interlayer insulating film 11 from the lower layer. Subsequently, the Ti film, Al alloy film, and titanium nitride film are patterned by dry etching using a photoresist film (not shown) patterned by photolithography as a mask, thereby forming a Ti film, an Al alloy film, and a nitride film. The wiring 17 made of a laminated film of a titanium film can be formed.
[0053]
Next, after removing the photoresist film used for patterning the wiring 17, a silicon oxide film is deposited on the wafer 1 by, for example, a CVD method as shown in FIG. Subsequently, the surface of the silicon oxide film is polished by a CMP method to be flattened, and an interlayer insulating film 18 is formed.
[0054]
Subsequently, a contact hole 19 is formed above the wiring 17 by dry-etching the interlayer insulating film 18 using the photoresist film as a mask. Next, a Ti (titanium) film, an Al alloy film, and a titanium nitride film are sequentially deposited from the lower layer on the interlayer insulating film 18 including the inside of the contact hole 19. Next, the Ti film, the Al alloy film, and the titanium nitride film are patterned by dry etching using a photoresist film (not shown) patterned by the photolithography technique as a mask, so that the Ti film, the Al alloy film, and the titanium nitride film are formed. The wiring 20 made of a film stack is formed, and the semiconductor device of the first embodiment is manufactured. Note that wiring may be formed in a further multilayer by repeating the process shown in FIG.
[0055]
As described above, the invention made by the inventor has been specifically described based on the embodiment of the invention. However, the invention is not limited to the embodiment and can be variously modified without departing from the gist thereof. Needless to say, there is.
[0056]
In the above-described embodiment, the case where a dilute hydrochloric acid aqueous solution is used as the acid aqueous solution that reacts with higher amines to form a salt is exemplified. ₃ COOH) or propionic acid (C ₂ H ₅ (COOH) may be used.
[0057]
【The invention's effect】
The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.
[0058]
That is, when a new UF module is washed, the higher amines contained in the UF module are converted into higher amine salts by filling the UF module with an acid aqueous solution, and then the acid aqueous solution is discharged from the UF module. Since pure water is passed through the UF module to remove amines contained in the UF module, the time required for the cleaning process and the amount of pure water can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a pure water production system for semiconductor production used for producing a semiconductor device according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a configuration of a UF unit included in a system for manufacturing ultrapure water used for manufacturing a semiconductor device according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram of a UF module included in the UF unit shown in FIG. 2;
FIG. 4 is a sectional view of a main part of the UF module shown in FIG. 3;
FIG. 5 is an explanatory view of a hollow fiber membrane (external pressure type) forming the UF module shown in FIG.
FIG. 6 is an explanatory view of a cleaning facility for cleaning the UF module shown in FIG. 3;
FIG. 7 is a flowchart illustrating a step of cleaning the UF module illustrated in FIG. 3;
8 is an explanatory diagram showing the relationship between the concentration of a dilute hydrochloric acid aqueous solution used for cleaning the UF module shown in FIG. 3 and the residual amount of higher amine in the UF module.
FIG. 9 is a fragmentary cross-sectional view for explaining the method for manufacturing the semiconductor device according to one embodiment of the present invention;
10 is a fragmentary cross-sectional view of the semiconductor device during a manufacturing step following that of FIG. 9;
11 is a fragmentary cross-sectional view of the semiconductor device during a manufacturing step following that of FIG. 10;
12 is a fragmentary cross-sectional view of the semiconductor device during a manufacturing step following that of FIG. 11;
13 is a fragmentary cross-sectional view of the semiconductor device during a manufacturing step following that of FIG. 12;
[Explanation of symbols]
1 wafer
2 Element isolation groove
3 Silicon oxide film
4 p-type well
5 n-type well
6 Gate insulating film
7 Gate electrode
8 n-type semiconductor region (source, drain)
9 p-type semiconductor region (source, drain)
11 Interlayer insulating film
13 Contact hole
14 Titanium nitride film
15 W film
16 plug
17 Wiring
18 interlayer insulating film
19 Contact hole
20 Wiring
ASPE acid supply equipment (acid aqueous solution supply means)
CV1-CV7 Shut-off valve
FILT, FLT2-FLT5 Filter
FM1-FM3 flow meter
GPE gas supply equipment (gas supply means)
HEXC heat exchanger
IEXC ion exchange resin
KOT housing
P1 to P7 process
PG1 to PG3 pressure gauge
PUMP pure water pump
PWPE pure water supply equipment (pure water supply means)
Qn n-channel type MISFET
Qp p-channel type MISFET
RV1 to RV3 check valve
TANK pure water tank
TYM hollow fiber membrane
UFM UF module
UFU UF unit
USE Semiconductor Manufacturing Line
UVOX Low pressure UV oxidation equipment

Claims (5)

A step of subjecting the semiconductor wafer to a first wet treatment using secondary pure water produced by removing the particulate foreign matter in the primary pure water by passing the primary pure water through the ultrafiltration module. Including, for the ultrafiltration module before the production of the secondary pure water,
(A) attaching the ultrafiltration module to a first cleaning system having pure water supply means and acid aqueous solution supply means;
(B) introducing an acid aqueous solution from the acid aqueous solution supply means into the first cleaning system, and filling the ultrafiltration module with the acid aqueous solution;
(C) discharging the acid aqueous solution out of the first cleaning system after leaving the ultrafiltration module filled with the acid aqueous solution for a predetermined time;
(D) after the step (c), flowing pure water from the pure water supply means into the first cleaning system to remove the acid aqueous solution remaining in the ultrafiltration module;
A method for manufacturing a semiconductor device, comprising performing a cleaning process including: A step of subjecting the semiconductor wafer to a first wet treatment using secondary pure water produced by removing the particulate foreign matter in the primary pure water by passing the primary pure water through the ultrafiltration module. Including, for the ultrafiltration module before the production of the secondary pure water,
(A) attaching the ultrafiltration module to a first cleaning system having pure water supply means and acid aqueous solution supply means;
(B) introducing an acid aqueous solution from the acid aqueous solution supply means into the first cleaning system, and filling the ultrafiltration module with the acid aqueous solution;
(C) discharging the acid aqueous solution out of the first cleaning system after leaving the ultrafiltration module filled with the acid aqueous solution for a predetermined time;
(D) after the step (c), flowing pure water from the pure water supply means into the first cleaning system to remove the acid aqueous solution remaining in the ultrafiltration module;
Wherein the acid aqueous solution is a dilute hydrochloric acid aqueous solution or an organic acid aqueous solution. A step of subjecting the semiconductor wafer to a first wet treatment using secondary pure water produced by removing the particulate foreign matter in the primary pure water by passing the primary pure water through the ultrafiltration module. Including, for the ultrafiltration module before the production of the secondary pure water,
(A) attaching the ultrafiltration module to a first cleaning system having pure water supply means and acid aqueous solution supply means;
(B) introducing an acid aqueous solution from the acid aqueous solution supply means into the first cleaning system, and filling the ultrafiltration module with the acid aqueous solution;
(C) discharging the acid aqueous solution out of the first cleaning system after leaving the ultrafiltration module filled with the acid aqueous solution for a predetermined time;
(D) after the step (c), flowing pure water from the pure water supply means into the first cleaning system to remove the acid aqueous solution remaining in the ultrafiltration module;
Performing the cleaning treatment including the step (b), the step (c) and the step (d), wherein the ionized amine in the pure water discharged out of the first cleaning system in the step (d) Alternatively, the method is repeated until the concentration of the ionized amine-based substance becomes equal to or lower than a predetermined first concentration. A step of subjecting the semiconductor wafer to a first wet treatment using secondary pure water produced by removing the particulate foreign matter in the primary pure water by passing the primary pure water through the ultrafiltration module. Including, for the ultrafiltration module before the production of the secondary pure water,
(A) attaching the ultrafiltration module to a first cleaning system having a pure water supply unit, an acid aqueous solution supply unit, and a gas supply unit;
(B) introducing an acid aqueous solution from the acid aqueous solution supply means into the first cleaning system, and filling the ultrafiltration module with the acid aqueous solution;
(C) discharging the acid aqueous solution out of the first cleaning system after leaving the ultrafiltration module filled with the acid aqueous solution for a predetermined time;
(D) after the step (c), introducing a predetermined first gas into the first cleaning system from the gas supply means to remove the acid aqueous solution remaining in the ultrafiltration module;
(E) after the step (d), flowing pure water from the pure water supply means into the first cleaning system to remove the acid aqueous solution remaining in the ultrafiltration module;
(F) after the step (e), introducing the first gas from the gas supply means into the first cleaning system to remove the pure water remaining in the ultrafiltration module;
A method for manufacturing a semiconductor device, comprising performing a cleaning process including: A step of subjecting the semiconductor wafer to a first wet treatment using secondary pure water produced by removing the particulate foreign matter in the primary pure water by passing the primary pure water through the ultrafiltration module. Including, for the ultrafiltration module before the production of the secondary pure water,
(A) attaching the ultrafiltration module to a first cleaning system having a pure water supply unit, an acid aqueous solution supply unit, and a gas supply unit;
(B) introducing an acid aqueous solution from the acid aqueous solution supply means into the first cleaning system, and filling the ultrafiltration module with the acid aqueous solution;
(C) discharging the acid aqueous solution out of the first cleaning system after leaving the ultrafiltration module filled with the acid aqueous solution for a predetermined time;
(D) after the step (c), introducing a predetermined first gas into the first cleaning system from the gas supply means to remove the acid aqueous solution remaining in the ultrafiltration module;
(E) after the step (d), flowing pure water from the pure water supply means into the first cleaning system to remove the acid aqueous solution remaining in the ultrafiltration module;
(F) after the step (e), introducing the first gas from the gas supply means into the first cleaning system to remove the pure water remaining in the ultrafiltration module;
Wherein the first gas is dry air or an inert gas.

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