JPH07142395A - Method of manufacturing semiconductor device - Google Patents

Abstract

PURPOSE:To decreased adhering carbon content by the contamination of organic materials by depositing films that constitutes circuit elements on a silicon layer on a substrate, that is cleaned by ultrasonic cleaning, after immersing and storing in ultra pure water acidified by electrolyzing. CONSTITUTION:A substrate with a silicon layer, of which organic material is removed by the ultrasonic cleaning with a mixture of ammonia water, hydrogen peroxide water and pure water that has etching effect, is immersed in an electrolyzing bath 1. After storing the immersed substrate, the ultra pure water for a semiconductor is supplied from an ultra pure water tank 5 to the electrolyzing bath 1 and electrolyzing with an anode plate 3 surrounded by a cathode plate 2, and a separator film 4, acidified ultra pure water is obtained. In this state a WSi film that constitutes the circuit elements on the silicon layer of the substrate is deposited. Thus, since, the surface of the silicon layer is shielded from the atmosphere by the acidified ultra pure water, adherence of the synthetic material is prevented and adherence of WSi film is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention prevents a film of tungsten silicide (WSi) or the like deposited on the surface of a monocrystalline, polycrystalline or amorphous silicon layer from being peeled off during the process or over time. The present invention relates to a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art A WSi film is often used for forming a wiring layer, an electrode, etc. on a single crystal, polycrystal or amorphous silicon layer.

Conventionally, when depositing a WSi film on a substrate having a monocrystalline, polycrystalline or amorphous silicon layer, the substrate storage time before cleaning and depositing the WSi film is within 48 hours. In the case of, the WSi film was deposited without treatment, and when the storage time of the substrate before depositing the WSi film exceeded 48 hours, H ₂ SO ₄ / H was added to remove the molecular contaminants on the surface of the substrate. _A WSi film was deposited after cleaning with a ₂ O ₂ / H ₂ O mixed solution and a nitric acid aqueous solution.

In this case, H ₂ SO ₄ / H ₂ O ₂ / H ₂ O
The organic substance mainly attached to the surface of the substrate is washed with the mixed liquid, and the metallic substance is washed with the nitric acid aqueous solution.

However, the substrate before depositing the WSi film
Clean loop while being stored in a synthetic resin carrier.
If left in the chamber, the substrate can be stored within 48 hours.
Even if the WSi film deposited on the substrate is
Peeling occurs during or over time to reduce yield and reduce reliability.
The reliability of a device using such a substrate
To ensure that a WSi film is deposited on the silicon layer
Immediately before the process, set the substrate to H ₂SO_Four/ H₂O₂/ H₂O mixture
It will be necessary to wash with combined solution and nitric acid,
There has been a problem that the number of steps for that is increased.

[0006]

In view of the above problems, the present invention reduces the amount of carbon adhering due to organic substance contamination (molecular contamination) by optimizing the substrate cleaning method and storage method. It is an object of the present invention to prevent peeling of a film forming a circuit element such as a wiring layer formed thereover.

[0007]

In a method of manufacturing a semiconductor device according to the present invention, the surface of a substrate having a monocrystalline, polycrystalline or amorphous silicon layer is treated with ammonia water / hydrogen peroxide water / pure water. After ultrasonic cleaning with the mixed solution, a step of depositing a film constituting a circuit element on the silicon layer was adopted.

In another method of manufacturing a semiconductor device according to the present invention, the surface of a substrate having a single crystal, polycrystal or amorphous silicon layer is annealed in an inert gas such as He or N ₂ . Then, a step of depositing a film forming a circuit element on the silicon layer was adopted.

In another method of manufacturing a semiconductor device according to the present invention, the surface of a substrate having a monocrystalline, polycrystalline or amorphous silicon layer is exposed to oxygen, inert gas,
A step of irradiating the surface of the silicon layer with ultraviolet light in a vacuum, atmosphere or hydrogen, and then treating the surface of the silicon layer with HF in a vapor phase or a liquid phase, and then depositing a film constituting a circuit element on the silicon layer. Adopted.

In another method of manufacturing a semiconductor device according to the present invention, a substrate having a cleaned single crystal, polycrystal or amorphous silicon layer is electrolyzed in ultrapure water. After immersing in the substrate and storing it, a process of depositing a film constituting a circuit element on the silicon layer was adopted.

Further, in another method of manufacturing a semiconductor device according to the present invention, the substrate having a cleaned single crystal, polycrystal or amorphous silicon layer is 5 ppm to 50 ppm.
A step of depositing a film constituting a circuit element on the silicon layer after immersing and storing it in a ppm HF aqueous solution was adopted.

In these methods of manufacturing a semiconductor device, a conductor such as WSi is used as a film forming a circuit element, and peeling of the conductor film can be prevented.

[0013]

The cause of peeling of a film forming a circuit element such as a WSi film deposited on a substrate having a single crystal, polycrystal or amorphous silicon layer is adhered on the surface of the silicon layer. Silicon layer and W by organic substance (adhered carbon)
This is because the adhered state between the Si film and the like deteriorates. Therefore, in order to prevent peeling of this film, the organic substance adhered to the surface of the silicon layer is washed immediately before forming the film on the silicon layer. Or after cleaning, this silicon layer does not contaminate the silicon layer and does not form a native oxide film on the silicon layer,
It is necessary to reduce the amount of carbon deposited on the surface of the silicon layer by storing it in a manner that does not attack the silicon layer and is shielded from the atmosphere by a substance that does not require additional water washing.

In this way, the surface of the silicon layer is washed,
Alternatively, if the cleaned silicon layer is stored while being shielded from the atmosphere, the effect of molecular contamination of the silicon layer by organic substances in the atmosphere can be eliminated, and W deposited on the silicon layer can be removed.
It is possible to prevent peeling of a film such as a Si film.

In the present invention, as is clear from the examples described below, a method of cleaning a single crystal, polycrystal or amorphous silicon layer uses a mixed solution of ammonia water / hydrogen peroxide water / pure water. Ultrasonic cleaning, annealing in an inert gas such as He, N ₂ , oxygen, in an inert gas,
As a method for storing a cleaned single crystal, polycrystal or amorphous silicon layer, which employs irradiation with ultraviolet rays in a vacuum, atmosphere or hydrogen, and subsequent treatment with HF in a gas phase or a liquid phase, Immersion in ultrapure water acidified by electrolysis, 5ppm to 50ppm HF
Immersion in an aqueous solution was adopted.

According to the method of manufacturing a semiconductor device of the present invention,
It is possible to prevent peeling of a film such as a WSi film caused by molecular contamination (organic substance), and it is not necessary to wash the single crystal, polycrystal or amorphous silicon layer after washing or storage, so that the process The number can be kept to a minimum.

[0017]

EXAMPLES Examples of the present invention will be described below.

(First Embodiment) In this embodiment, the surface of a substrate having a single crystal silicon layer such as a silicon wafer is superposed with a mixed solution of ammonia water / hydrogen peroxide water / pure water having an etching effect. After removing the organic substance adhering to the surface of the single crystal silicon layer by sonic cleaning, WSi
A film is deposited to manufacture a semiconductor device.

According to the method of manufacturing a semiconductor device of this embodiment, since the organic substance (carbon amount) attached to the surface of the single crystal silicon layer can be completely removed, the WSi film deposited on the organic substance can be completely removed. It is possible to solve the problem that the WSi film peels off during or after the step of patterning the WSi film to form the wiring layer.

(Second Embodiment) In this embodiment, the surface of a substrate having a monocrystalline silicon layer such as a silicon wafer is subjected to WSi in an inert gas such as He or N ₂ afterwards.
A semiconductor device is manufactured by depositing a WSi film after removing the organic substance adhering to the surface of the single crystal silicon layer by annealing at a temperature of about 400 ° C. which is the temperature at which the film is deposited.

According to the method of manufacturing a semiconductor device of this embodiment, the organic substance (carbon amount) attached to the surface of the single crystal silicon layer can be completely removed, so that the WSi film deposited on it can be removed. During the process of forming a wiring layer by patterning the WSi film by improving the adhesion with
After that, the problem that the WSi film is peeled off can be solved.

(Third Embodiment) In this embodiment, the wavelength of oxygen, inert gas, vacuum, air or hydrogen is applied to the surface of a substrate having a monocrystalline silicon layer such as a silicon wafer. After irradiating with ultraviolet rays of 186 nm and then treating the surface of the silicon layer with vapor phase or liquid phase HF, a WSi film is deposited on the single crystal silicon layer to manufacture a semiconductor device.

When the single crystal silicon layer is irradiated with ultraviolet rays,
Organic substances attached to the surface are decomposed and scattered as CO ₂ . In this case, when ultraviolet rays are irradiated in an inert gas and in a vacuum, the surface of the single crystal silicon layer does not deteriorate due to a chemical reaction with the atmosphere. Further, when ultraviolet rays are irradiated in oxygen and air, the surface of the single crystal silicon layer is slightly oxidized, but products such as oxides can be easily removed by the subsequent HF treatment in the vapor phase or liquid phase. can do.

When ultraviolet rays are irradiated in hydrogen,
The chlorine-based organic substance adhering to the surface of the single crystal silicon layer scatters as hydrochloric acid, and Si on the surface of the single crystal silicon layer
Atoms are terminated with H to become hydrophobic and have the effect of preventing subsequent attachment of organic materials. Then, again, the SiO ₂ film that has been produced is reduced.

According to the method of manufacturing a semiconductor device of this embodiment, the organic substance (carbon amount) attached to the surface of the single crystal silicon layer can be completely removed, and in particular, ultraviolet rays are irradiated in hydrogen. In that case, the surface becomes hydrophobic and the organic material does not adhere to it thereafter, so that a clean surface can be maintained, the adhesion with the WSi film deposited thereon is improved, and the WSi film is patterned to form a wiring. The problem that the WSi film peels off during or after the step of forming the layer can be solved.

(Fourth Embodiment) In this embodiment, for example, a substrate having a single crystal silicon layer cleaned by the cleaning method described in the first, second and third embodiments is used. After being immersed and stored in ultrapure water acidified (H ⁺ rich) by electrolysis, a WSi film is deposited on this single crystal silicon layer to manufacture a semiconductor device.

FIG. 1 is an explanatory diagram of electrolysis of ultrapure water according to the fourth embodiment. In this figure, 1 is an electrolytic cell, 2 is a cathode plate, 3 is an anode plate, 4 is a diaphragm, 5 is an ultrapure water tank, 6 is an alkaline ionized water outlet, and 7 is an acidic ionized water outlet.

In order to generate acidified ultrapure water for dipping and storing a semiconductor substrate in this embodiment, a cathode plate 2 and an anode plate 3 surrounded by a diaphragm 4 are placed in an electrolytic cell 1. The ultrapure water for semiconductors in the ultrapure water tank 5 arranged opposite to each other is supplied into the electric field tank 1 and into the diaphragm 4 containing the anode plate 3, and the pure water which becomes OH ^- rich by electrolysis is supplied. The alkaline ionized water discharge port 6 is discharged, and the acidified (H ⁺ rich) pure water is discharged from the acidic ionized water discharge port 7.

According to the method of manufacturing a semiconductor device of this embodiment, the surface of the cleaned single-crystal silicon layer is shielded from the atmosphere by the ultrapure water acidified by electrolysis, so that an organic substance may be attached. Since a natural oxide film is not formed and the surface of the single crystal silicon layer is not corroded, the surface of the single crystal silicon layer can be kept clean for a long time. WS deposited on
It is possible to improve the adhesion with the i film and solve the problem that the WSi film is peeled off during or after the step of patterning the WSi film to form the wiring layer.

Further, since the acidified ultrapure water is originally ultrapure water for semiconductors, there is no need to perform a water washing treatment before depositing the WSi film, which can reduce the number of steps and is required for rewashing. You can reduce or eliminate the use of medicines.

(Fifth Embodiment) In this embodiment, for example, a substrate having a single crystal silicon layer cleaned by the cleaning method described in the first, second and third embodiments is used. The semiconductor device is manufactured by immersing and storing in a 5 ppm to 50 ppm HF aqueous solution and then depositing a WSi film on this single crystal silicon layer.

FIG. 2 is an explanatory view of the effect of the cleaning method of the single crystal silicon layer of the fifth embodiment, (A) shows the measurement result of the cleaning method of the first embodiment, and (B) is in the atmosphere. It shows the measurement results after storage in.

FIG. 2A shows a semiconductor substrate having a single crystal silicon layer obtained by removing organic substances with ammonia water / hydrogen peroxide solution / pure water and further removing metal with nitric acid (HNO ₃ ). FIG. 4 is a gas chromatogram of a degassed substance from a single crystal silicon layer when the temperature is raised to 400 ° C. after being stored in a PFA carrier and left in a clean room for 20 days.

In this case, as shown in the figure, it can be seen that the surface of the silicon layer was contaminated with various molecules. The pollutants are as follows. a C ₅ H ₁₀ isomer (dimethylcyclopropane, methylbutene, etc.) b THF c Butanol d C ₆ H ₁₂ , C ₈ H ₁₆ isomer (dimethylbutene, hexene, methylpentene, cyclohexene, methyleneheptane, dimethylhexene, Methylheptene, octene, etc.) f, g, h, i, j C ₈ H ₁₄ O, C ₉ H ₁₈ isomers (cyclohexylmethylketone, 3-ethylheptene,
(Trimethylcyclohexane, etc.) l Ester organic substance n Phthalic anhydride p Unidentified substance

In FIG. 2B, a semiconductor substrate having a single crystal silicon layer is pretreated in the same manner as in FIG. 2A, and then immersed in a 10 ppm HF aqueous solution and stored for 20 days. 3 is a gas chromatogram of the degassed substance from the silicon layer when the temperature is raised to 400 ° C. in this case,
Since the peak at the left end is noise due to air, it can be seen that almost no organic substance is attached.

In this case, the concentration of the HF aqueous solution is 10 pp.
Since it is m, a natural oxide film is not formed on the surface of the silicon layer and a washing treatment is not necessary, so that the number of steps can be reduced and the amount of chemicals used can be reduced.

As shown in FIG. 2A, when the substrate is contaminated with an organic substance, the surface of the substrate having the monocrystalline silicon layer is treated with ammonia water / hydrogen peroxide water / pure water according to the first embodiment. Ultrasonic cleaning in a mixed solution of, or according to the second embodiment, 400 ° C. in an inert gas such as He and N _2.
2 or by UV irradiation in oxygen, inert gas, vacuum, atmosphere or hydrogen according to the third embodiment, and treatment with HF in vapor phase or liquid phase.
A clean single crystal silicon layer as shown in (B) can be obtained.

FIG. 3 is an explanatory view (1) of the effect of the method for storing the single crystal silicon layer of the fifth embodiment. This figure shows a substrate with a cleaned single crystal silicon layer at 1 ppm HF.
XPS (X-ray) when immersed and stored in an aqueous solution
Photo-emission Spectroscop
The result of analysis by y) is shown. in this case,
It can be seen that a natural oxide film is formed on the surface of the single crystal silicon layer because the fluorine concentration is low.

FIG. 4 is an explanatory view (2) of the effect of the storage method of the single crystal silicon layer of the fifth embodiment. This figure shows the results of XPS analysis when a substrate having a cleaned single crystal silicon layer was immersed in a 500 ppm HF aqueous solution and stored. In this case, since the fluorine concentration is high, it is understood that the natural oxide film is not formed on the surface of the single crystal silicon layer. However, since fluorine remains on the surface of the single crystal silicon layer, it is necessary to wash with water. In addition, the surface of the single crystal silicon layer is ~ 100Å
Etched to a degree.

FIG. 5 is a diagram showing the relationship between the fluorine and the cleaning time on the surface of the single crystal silicon layer. This figure shows the relationship between the fluorine on the surface of the single-crystal silicon layer and the cleaning time when the substrate having the cleaned single-crystal silicon layer was immersed and stored in a 500 ppm HF aqueous solution, and the horizontal axis represents the cleaning time. And the vertical axis represents the coverage of bound fluorine on the surface of the single crystal silicon layer with respect to the silicon (100) surface atoms.

According to this figure, the substrate having the washed single-crystal silicon layer was immersed in a 500 ppm HF aqueous solution for storage, and had a coverage of about 0.08 when not washed with water, and decreased with the washing time. Although it decreases to nearly 0.02 in about 100 seconds, it is found that this value is almost the same as that in the case of not rinsing with water after immersion in 10 ppm of HF, and that it is almost the same as that after cleaning before immersion.

According to the above circumstances and the experimental results when the HF concentration is changed, the optimum concentration of the HF aqueous solution in which the substrate having the single crystal silicon layer is dipped and stored is such that a natural oxide film is not formed and fluorine is not contained. Low residence amount, 5 ppm to 5
It can be said that the range of 0 ppm is the most suitable. When the above range is exceeded downward, the formation of a natural oxide film becomes remarkable, and when it exceeds the above range, the surface of the single crystal silicon layer is etched,
Residual amount of fluorine becomes significant.

In each of the above embodiments, the substrate having the single crystal silicon layer was described, but the present invention is also applicable to cleaning and storage of the substrate having the polycrystalline silicon layer or the amorphous silicon layer. It can be applied similarly.

In the above embodiment, the case where the film formed on the silicon layer is the WSi film has been described.
The present invention can be widely applied to the case of forming a conductor film, an insulator film, a dielectric film, and an oxide superconductor film on a silicon layer.

[0045]

As described above, according to the present invention,
It is possible to store a semiconductor substrate having a single crystal, polycrystal, or amorphous silicon layer in a clean state without increasing the number of steps, and to improve the organic substances generated on the surface of such a semiconductor substrate. Because the pollution can be washed
It greatly contributes to the improvement of throughput and cost saving.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of electrolysis of ultrapure water according to a fourth embodiment.

FIG. 2 is an explanatory view of effects of the cleaning method for a single crystal silicon layer of the fifth embodiment, (A) shows measurement results of the cleaning method of the first embodiment, and (B) is stored in the atmosphere. The subsequent measurement results are shown.

FIG. 3 is an effect explanatory diagram (1) of the storage method of the single crystal silicon layer of the fifth embodiment.

FIG. 4 is an effect explanatory view (2) of the storage method of the single crystal silicon layer of the fifth embodiment.

FIG. 5 is a diagram showing a relationship between fluorine on the surface of a single crystal silicon layer and cleaning time.

[Explanation of symbols]

 1 Electrolyte tank 2 Cathode plate 3 Anode plate 4 Diaphragm 5 Ultrapure water tank 6 Alkaline ion water outlet 7 Acidic ion water outlet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/306 23/29 23/31 // B08B 3/12 Z 2119-3B

Claims (5)

[Claims] 1. A surface of a substrate having a monocrystalline, polycrystalline or amorphous silicon layer is treated with ammonia water / hydrogen peroxide solution /
A method for manufacturing a semiconductor device, which comprises ultrasonically cleaning with a mixed solution of pure water, and then depositing a film constituting a circuit element on the silicon layer. 2. A film constituting a circuit element on a surface of a substrate having a monocrystalline, polycrystalline or amorphous silicon layer, which is annealed in an inert gas such as He or N _2. A method of manufacturing a semiconductor device, comprising: 3. The surface of a substrate having a monocrystalline, polycrystalline or amorphous silicon layer is irradiated with ultraviolet rays in oxygen, inert gas, vacuum, atmosphere or hydrogen, and then the silicon layer is irradiated. A method for manufacturing a semiconductor device, comprising: treating the surface of the substrate with vapor phase or liquid phase HF, and then depositing a film forming a circuit element on the silicon layer. 4. A substrate having a washed single crystal, polycrystalline or amorphous silicon layer is immersed in ultrapure water acidified by electrolysis and stored, and then the substrate is placed on the silicon layer. A method of manufacturing a semiconductor device, comprising depositing a film that constitutes a circuit element. 5. A substrate having a cleaned single crystal, polycrystal or amorphous silicon layer is added at 5 ppm to 50 pp.
A method for manufacturing a semiconductor device, which comprises immersing in a HF aqueous solution of m for storage and then depositing a film constituting a circuit element on the silicon layer.