JP2001044429A - Method and device for pre-process for forming gate insulating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate pre-process method for forming a gate insulating film, superior in electric characteristics by eliminating water mark in principle and forming a chemical oxide film with no organism and other contaminant sticking to a wafer surface. SOLUTION: Related to a gate insulating film formation pre-process device 100 when a gate oxide film is formed on a silicon wafer 110, a one-bath washing tab 105 is provided in a rinsing device 102 provided next to a clean room 101 which holds the silicon wafer 110, in which a first process where the surface of silicon wafer is cleaned using hydrogen fluoride(HF), a second process where the hydrogen fluoride(HF) used in the first process is replaced by pure water, and a third process where the pure water used in the second process is replaced by hydrogen peroxide dilution water to form a chemical oxide film on the surface of the silicon wafer are performed succeedingly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment method for forming a gate insulating film and a pretreatment apparatus for forming a gate insulating film, and more particularly to a pretreatment method for forming a gate insulating film having a thickness of 3.0 nm or less. And a method and apparatus for cleaning and cleaning a silicon wafer.

[0002]

2. Description of the Related Art Conventionally, particles, metals,
In order to remove contamination such as organic substances and surface coatings (natural oxide film, adsorbed molecules), and to remove watermarks formed on the silicon wafer,
Wet cleaning methods are widely used. The basic technology is the RCA cleaning method developed in the 1960's, and many cleaning processes using this technology have been proposed.

The most general cleaning process performed before forming a gate insulating film will be described below.

[0004] First, to remove particles
APM (NH_FourOH / H_TwoO_Two/ H _TwoO) (Ammo
Nium Hydroxide, Hydrogen P
eroxide Mix) Washing is performed. APM cleaning
The basic condition is that NH _FourOH (29% water soluble
Liquid), H_TwoO_Two(30% aqueous solution), NH_FourOH / H_TwoO_Two
/ H_TwoO = 1: 1: 5 to 1: 2: 7 and the temperature of the solution
Degree to 65 to 85 degrees, and 5 to 20 min. Perform processing
U. Next, perform pure water cleaning, and then perform APM cleaning.
DHF cleaning (fluoride) to remove the formed oxide film
Hydrogen (HF) / H_TwoO, Dilute Hytrofl
(oric Acid) washing is performed. The DHF cleaning
The basic conditions are that hydrogen fluoride (HF) (49%
Aqueous solution), hydrogen fluoride (HF): H_TwoO = 1: 30
In a ratio of 45 to 60 sec. Is performed. The D
After HF cleaning, perform pure water cleaning, and finally Linsandra
Perform spin drying with ear.

However, in the above-mentioned method, DHF
When the silicon surface is exposed after the treatment, the surface becomes hydrophobic, and water droplets remain on the surface when the silicon wafer is pulled up from the chemical solution tank. Such water droplets become a watermark after spin drying. The watermark is
It is considered that this is a natural oxide film formed locally through a water droplet during the transfer / drying of the wafer, or a stain left after drying after the oxide film elutes in the water droplet. Such a watermark becomes masking in a subsequent etching process or becomes a hindrance in a film forming process, thereby deteriorating device characteristics. Therefore, how to suppress the watermark in the cleaning process is an issue of the cleaning and drying technique.

[0006] In the spin drying process, electrostatic attraction of particles due to electrification of a high-speed rotating wafer, generation of dust from a rotating mechanism portion, and generation / adhesion of contamination mist occur, so that the wafer surface is easily stained. Further, since a natural oxide film having a thickness of 3.0 nm or more is usually formed on the exposed silicon surface, there is a great problem in forming a gate insulating film having a thickness of 3.0 nm or less.

As a method of treating a semiconductor wafer without lifting it into the air in order to suppress the generation of the watermark and the generation of a natural oxide film, for example, Japanese Patent Laid-Open No.
JP-A-196465 and a method using isopropyl alcohol (IPA) as a drying step have been proposed. Japanese Patent Application Laid-Open No. 6-196465 describes a method of suppressing the drying of a wafer during transfer, generation of a watermark, and generation of a natural oxide film by performing a cleaning process without lifting the wafer into the air. I have. That is, in the known example, a plurality of spray chambers for performing a chemical solution treatment and pure water cleaning are connected in series, and the wafers are sequentially moved in the connected spray chambers. For this reason, a partition curtain that can be opened and closed is provided at a continuous portion of each chamber.
With such an apparatus configuration, a cleaning process can be performed without exposing the wafer to the atmosphere. Further, it is easy to replace the processing chamber with N ₂ , and the generation of a natural oxide film can be prevented.

On the other hand, isopropyl alcohol (IPA)
In the IPA drying step (see FIG. 5) using a, there is no mechanical operating part such as a rotating part, so that there is little dust in the apparatus.
It is effective in suppressing watermarks. In a general IPA drying method, a liquefied IPA layer 403 is formed on a pure water layer 404, and water is slowly drained during rinsing. As a result, IPA
The boundary between the layer and the pure water layer is lowered, the particles 405 are removed from the surface of the wafer 401 at the boundary surface by the surface tension 406 of the water, and the water is replaced with IPA on the surface of the wafer, and the drying proceeds.

In order to suppress the watermark, a hydrogen peroxide solution containing 1 to 10% of hydrogen peroxide is immersed on the silicon wafer for about 1 to 20 minutes to form a silicon dioxide layer having a thickness of 1.0 to 3.0 nm. Has been proposed.
That is, according to JP-A-10-116806, since the silicon dioxide layer is hydrophilic with respect to water, the water does not become spherical water droplets but adheres thinly and uniformly. The silicon wafer is rotated to remove the water. Through the above steps, generation of a watermark is suppressed.

[0010]

The above-mentioned cleaning method has the following problems.

That is, the first problem is that generation of a watermark cannot be eliminated in principle. That is, a method of processing a semiconductor wafer without lifting it into the air in order to suppress the generation of a watermark and the generation of a natural oxide film is disclosed in the above-mentioned JP-A-6-196465. However, hydrogen fluoride (HF)
After the cleaning, pure water cleaning is performed, and the silicon wafer is rotated using a semiconductor wafer cleaning device in order to remove moisture adhering to the silicon surface. Therefore, the watermark cannot be completely eliminated. This is because dissolved oxygen is present in water, and an oxidization reaction by dissolved oxygen occurs from water droplets. Therefore, even if JP-A-6-196465 is used, the watermark cannot be completely eliminated in principle.

Further, as described above, in the spin drying process, electrostatic attraction of particles due to charging of the high-speed rotating wafer, generation of dust from the rotating mechanism, and generation / adhesion of contamination mist occur, so that the wafer surface is easily contaminated. This is also a problem.

As a method of suppressing the watermark, there is a method of covering the surface with an oxide film and making it hydrophilic with respect to water, as described in JP-A-10-116806. However, Japanese Patent Application Laid-Open No. 10-116806
The use of the publication does not completely eliminate the watermark. This is because the wafer is lifted into the atmosphere when the wafer is moved to the hydrogen peroxide treatment after the hydrogen fluoride (HF) cleaning. At this time, the surface of the wafer is hydrophobic, and a local oxidation reaction occurs from water droplets. further,
In the pretreatment in which an oxide film having a thickness of 1.0 to 3.0 nm is formed, it is difficult to form a gate insulating film having a thickness of 3.0 nm or less with good control.

It is also reported that the use of the above-described IPA drying step significantly suppresses watermarks. However, also in this case, since the hydrophobic surface is exposed to the atmosphere before the IPA drying step, the watermark cannot be eliminated. As described above, the watermark cannot be eliminated in principle in the conventional method.

Further problems with the prior art for suppressing the watermark will be described below. That is, the second problem relating to the above is disclosed in Japanese Patent Laid-Open No. 10-116806.
In the method described in Japanese Patent Application Laid-Open Publication No. H10-209, the thickness of the oxide film formed in a hydrogen peroxide solution is 1.0 to 3.0 nm being too thick.
When this technique is used in a process for forming a gate insulating film having a thickness of 3.0 nm or less, a ratio of an oxide film formed in a cleaning step to the gate insulating film is large, and good electrical characteristics cannot be expected. . This is because an oxide film formed in a solution or in the atmosphere has a larger leak current than a normal thermal oxide film.

A third problem related to the above is contamination adhering to the surface during the drying process. In the spin drying process, electrostatic attraction of particles due to electrification of a high-speed rotating wafer, generation of dust from a rotating mechanism, and generation / adhesion of contamination mist occur, so that the wafer surface is easily stained.

On the other hand, it is said that IPA molecules remain on the surface after IPA drying, and there is a concern that it may affect the characteristics of the gate oxide film (K. MOTAI, T. Ito).
ga, and T.M. Irie, Extended Ab
structure of 1997, International
nal Conference on SolidSt
ate Devices and Material
s, Hamamatsu, p. 24-25 (199
7)). Therefore, even if the watermark is reduced using IPA drying, it is difficult to obtain a clean surface after drying.

In addition, Japanese Patent Application Laid-Open No. 4-113620 describes a method in which a silicon substrate is immersed in pure water containing ozone to form a silicon oxide film on a surface of a silicon exposed portion of the silicon substrate. JP-A-6-1635
Japanese Patent Application Laid-Open No. 08-08530 discloses a method for drying a substrate in which a step of immersing the substrate in pure water and a step of treating the substrate in a nitrogen gas atmosphere are repeated. In order to prevent contamination of the semiconductor device, a method of manufacturing a semiconductor device in which the treatment is performed twice with a hydrofluoric acid-based treatment solution and then treated with pure water is described, but in any case, the generation of a watermark as in the present invention is shown. There is no disclosure of a pretreatment method for forming a gate insulating film on a silicon wafer using hydrogen fluoride (HF), hydrogen peroxide, and pure water in order to prevent the above.

On the other hand, Japanese Patent Application Laid-Open No. 7-153728 discloses a method of treating particles using a mixed solution of ammonia, hydrogen peroxide and water in order to prevent particle contamination on a silicon wafer. JP-A-8-783
No. 73 discloses a method of forming a chemical oxide film by cleaning a silicon wafer with hydrogen peroxide and then cleaning it with an oxidizing cleaning solution.
The present invention discloses a pretreatment method for forming a gate insulating film on a silicon wafer using hydrogen fluoride (HF), hydrogen peroxide and pure water in order to prevent generation of a watermark as in the present invention. Not.

Accordingly, an object of the present invention is to improve the above-mentioned drawbacks of the prior art, and to be made in view of the above-mentioned problems in the pretreatment method for forming an ultra-thin gate insulating film having a thickness of 3.0 nm or less. By eliminating the generation of watermarks in principle and eliminating organic substances and other contaminants adhering to the wafer surface during the drying process or in the atmosphere, excellent electrical characteristics with a film thickness of 3.0 nm or less are obtained. An object of the present invention is to provide a silicon wafer pretreatment method and a pretreatment device capable of forming a gate insulating film.

[0021]

The present invention employs the following technical configuration to achieve the above object. That is, as a first aspect according to the present invention, when forming a gate oxide film on a silicon wafer,
A first step of cleaning the surface of the silicon wafer by using hydrogen fluoride (HF) on the silicon wafer; replacing the hydrogen fluoride (HF) used in the first step with pure water; And a third step of replacing the pure water used in the second step with a diluted solution of hydrogen peroxide and forming a chemical oxide film on the surface of the silicon wafer. A method for pre-treating a silicon wafer when a gate oxide film is formed on the silicon wafer, wherein a second aspect according to the present invention includes:
An apparatus for forming a gate oxide film on a silicon wafer, wherein at least the silicon wafer is placed in a cleaning device provided adjacent to a clean room holding the silicon wafer by using hydrogen fluoride (HF). A first step of cleaning the surface of the wafer, a second step of replacing the hydrogen fluoride (HF) used in the first step with pure water, and a pure step used in the second step. A gate oxide film is formed on a silicon wafer provided with a one-bath cleaning tank in which water is replaced with a hydrogen peroxide solution diluted solution and a third step of continuously forming a chemical oxide film on the surface of the silicon wafer is provided. This is a pretreatment apparatus for forming a gate insulating film when forming.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A pretreatment method for a silicon wafer and a pretreatment apparatus for forming a gate insulating film according to the present invention are as follows.
Since the technology configuration as described above is employed, the surface of the silicon wafer is cleaned by hydrogen fluoride (HF) cleaning to remove the silicon oxide film formed on the surface of the silicon wafer, After exposing the clean surface, the silicon wafer is continuously processed in a solution, so that generation of a watermark is basically eliminated.

Further, after washing with hydrogen fluoride (HF), the hydrogen fluoride (HF) is replaced with pure water, and the pure water is further replaced with a dilute solution of hydrogen peroxide, whereby hydrogen fluoride (H) is removed.
F) After the cleaning, a chemical oxide film is formed on the silicon surface using the oxygen in the diluted hydrogen peroxide solution without exposing the silicon wafer made of the silicon substrate to the atmosphere.

Thereafter, the silicon wafer is pulled up. At this time, since an oxide film has already been formed on the surface of the silicon wafer, no watermark is formed in the subsequent steps. That is, according to the first aspect of the present invention, it is possible to form a silicon wafer surface suitable for forming a flat and clean gate insulating film without generation of a watermark.

Further, according to another embodiment of the first aspect of the present invention, the silicon wafer is transferred into an ultra-high vacuum chamber through a drying step, and the temperature of the silicon wafer is raised to increase the temperature. The oxide film formed in the diluted hydrogen oxide solution is eliminated. The oxide film is 900 to 1
0 to 10 min. Is completely removed from the surface of the silicon wafer. At this time, during the drying step / while the wafer is being conveyed, it can be eliminated together with contaminants such as IPA molecules attached to the oxide film surface.

Finally, a gate insulating film having excellent electrical characteristics and a thickness of 3.0 nm or less is formed on the surface of the silicon wafer which has been subjected to the cleaning / cleaning process which is the pretreatment method of the silicon wafer according to the present invention. can do.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific example of a pretreatment method for a silicon wafer and a pretreatment apparatus for forming a gate insulating film on a silicon wafer according to the present invention will be described below in detail with reference to the drawings.

That is, FIG. 1 is a schematic plan view showing a configuration of a specific example of a pretreatment apparatus 100 for forming a gate insulating film according to the present invention, in which a gate oxide film is formed on a silicon wafer 110. In a cleaning apparatus 102 provided adjacent to a clean room 101 for holding the silicon wafer 110, at least the silicon wafer 110 is cleaned using hydrogen fluoride (HF) to clean the surface of the silicon wafer. A first step of cleaning, the first
A second step of replacing the hydrogen fluoride (HF) used in the second step with pure water, replacing the pure water used in the second step with a hydrogen peroxide solution diluted solution, A gate insulating film forming pretreatment apparatus 100 for forming a gate oxide film on a silicon wafer 110 provided with a one-bath cleaning tank 105 in which a third step of forming a chemical oxide film on the surface of the substrate 110 is continuously performed. It is shown.

Further, in the gate insulating film formation pretreatment apparatus 100 according to the present invention, the one-bath cleaning tank 10 is used.
No. 5 needs to be configured so that the surface of the silicon wafer is not exposed to the atmosphere while the first to third steps are performed.

On the other hand, in the pretreatment apparatus 100 for forming a gate insulating film according to the present invention, the cleaning apparatus 102 is further provided with a chemical treatment for removing adhering substances adhered to the surface of the silicon wafer 110. A first cleaning tank 103 for executing a first pre-cleaning step using an oxide film-forming chemical substance, and a second cleaning step for executing a second pre-cleaning step of cleaning the chemical oxide film-forming chemical substance with pure water. 2 washing tanks 1
04, the one-bath washing tank 105, and a drying tank 106 described later are desirably provided.

The first cleaning tank 103 for performing the first pre-cleaning step used in the gate insulating film formation pre-processing apparatus 100 according to the present invention includes the silicon wafer 11.
The main purpose is to remove particles adhering to the surface of No. 0, and for that purpose, for example, a mixed chemical solution composed of water, hydrogen peroxide and ammonia is used.

On the other hand, the one-bath cleaning tank 105 used in the gate insulating film formation pretreatment apparatus 100 according to the present invention includes a cleaning tank main body 120 holding the silicon wafer 110 and the cleaning tank main body 120. 120 and a processing liquid discharge unit 30 connected to the bottom of the processing liquid 120
2. Receiving tray 130 for receiving the processing liquid overflowing from cleaning tank main body 120, waste liquid discharging unit 303 provided at the bottom of receiving tray 130, and processing liquid introducing unit 30
It is preferable that a hydrogen fluoride (HF) supply unit 180, a hydrogen peroxide solution diluted solution supply unit 190, and a pure water supply unit 200, which are individually connected to each other via individual valve units, are provided in the apparatus.

Further, the processing solution introducing section 3 according to the present invention.
01 and the individual valve portions 213, 215, and 217 are individually connected via a mixing means 222. In the pretreatment apparatus 100 for forming a gate insulating film in the present invention,
A gate provided with an appropriate flow meter 220, 221 between each of the hydrogen fluoride (HF) supply unit 180, the diluted hydrogen peroxide solution supply unit 190, and the pure water supply unit 200 This is a pretreatment apparatus 100 for forming an insulating film.
The bottom of the cleaning tank body 120 according to the present invention is
It is also preferable that the mesh part 121 is formed at the partition part of the double bottom part. Further, the gate insulating film forming pretreatment apparatus 10 according to the present invention
At 0, after the drying tank 106, the silicon wafer 110 is further transported into the ultrahigh vacuum chamber 501, the temperature of the silicon wafer 110 is increased, and the chemical oxidation formed in the hydrogen peroxide diluted solution is performed. It is also desirable to provide a chemical oxide film detachment processing unit 108 for detaching the film. The chemical oxide film detachment processing unit 108 may be provided between the drying tank 106 and the clean room 101 in FIG. 1, or as shown in FIG. On the other hand, it may be provided at an appropriate position on the opposite side of the cleaning device 102.

Hereinafter, specific examples of the pretreatment apparatus for forming a gate insulating film and the pretreatment method for forming a gate insulating film according to the present invention will be described in detail with reference to embodiments.

That is, as shown in FIG.
10 is composed of at least four tanks: a one-bath washing tank 105 for performing hydrogen fluoride (HF) washing, pure water rinsing, and a treatment with a diluted solution of hydrogen peroxide in one bath, and finally an IPA drying treatment tank 106. I have. The silicon wafer 110 is transferred into the wet cleaning apparatus 102 from the class 1 clean room 101 side. The wafer 110 transported into the wet cleaning apparatus 102 is transported in each processing tank by a robot arm, and a cleaning and drying process is performed. After the washing and drying steps,
The wafer is transported again to the class 1 clean room 101 side. The pretreatment apparatus for forming a gate insulating film according to the present invention is of a batch processing type, and can clean 25 wafers at a time.

Here, the details of the one bath cleaning tank 105 will be described below with reference to FIG.

That is, the one-bath cleaning tank 105 includes a cleaning tank main body 120, a receiving tray section 130 for receiving a chemical solution overflowing from the upper portion of the cleaning tank main body 20, and a processing liquid introduction section 301 connected to the bottom of the cleaning tank main body 120. The treatment liquid introduction unit 3
Each chemical solution supply line 18 connected to 01
1, 191 and 201 and a waste liquid line 302. The chemical supply line 181 is provided with hydrogen fluoride (H
The supply line F) and the chemical supply line 191 constitute an H ₂ O ₂ supply line and the chemical supply line 201 respectively constitute a pure water supply line. The respective supply lines are mixed in an appropriate stirring introduction line 222 before entering the cleaning tank main body 120, and one or a plurality of chemicals are mixed at an appropriate ratio based on appropriate concentration conditions. The water is supplied into the cleaning tank main body 120 from the cleaning tank bottom 121 of the cleaning tank main body 120 while stirring.

A waste liquid discharge section 303 is provided at the bottom of the tray 130 and a hydrogen fluoride (HF) connected to a hydrogen fluoride (HF) supply section 180 connected to the processing liquid introduction section 301. ) Supply line 181, H ₂
H ₂ O ₂ supply line 19 connected to O ₂ supply section 190
1 and a pure water supply line 201 connected to the pure water supply unit 200 are provided with appropriate valve units 213, 215, and 2 respectively.
17 is connected to the stirring introduction line 222.

The bottom surface 121 of the washing tank has a double bottom, and is separated by a plate 122 having fine holes. By adopting such a structure, the processing chemical is supplied from the bottom surface of the cleaning tank main body 120 to the inside of the cleaning tank main body with good uniformity, and is efficiently replaced with another processing chemical previously supplied.

Vortex flowmeters 220 to 221 are provided in the chemical lines for hydrogen fluoride (HF) and H ₂ O ₂ to change the mixing ratio with pure water.

Further, each of the above chemicals supplied from the bottom of the cleaning tank main body 120 overflows from the upper portion of the cleaning tank main body 120 and passes through the receiving tray 130 to the concentrated waste liquid line 160 in the case of a hydrogen fluoride (HF) solution. In the case of the H ₂ O ₂ diluted solution, it is discharged to the diluted waste liquid line 170.

By adopting the above-described apparatus configuration, a cleaning step for eliminating generation of a watermark in principle becomes possible, and the pretreatment conditions of the present invention can be realized. That is, after removing the silicon oxide film by hydrogen fluoride (HF) cleaning and exposing the clean silicon surface, the hydrogen fluoride (HF) is replaced with pure water, and the pure water is further reduced to 0.6 to 1.0.
Replace with 5 wt% diluted hydrogen peroxide solution, and
min. By performing the inter-process, a chemical oxide film can be formed on the silicon surface by using oxygen in a diluted hydrogen peroxide solution without exposing the silicon wafer to the atmosphere after cleaning with hydrogen fluoride (HF).

According to the pretreatment method for forming a gate insulating film in the present invention, a thin chemical oxide film of about 0.6 to 1.0 nm that keeps the surface of the silicon wafer clean and uniform can be formed. . By performing such a processing operation, a flat and clean silicon substantially free of a watermark and covered with a chemical oxide film, which is necessary for forming a uniform gate insulating film of 3.0 nm or less. A wafer surface is obtained. Such a chemical oxide film, in a later step,
This is to separate from the surface of the silicon wafer and form a clean gate insulating film having a uniform thickness of 3.0 nm or less and free of impurities on the surface of the silicon wafer thereafter.

That is, as a specific example of the gate insulating film forming pretreatment method according to the present invention, as is apparent from the above description, when forming a gate oxide film on the silicon wafer 110, A first step of cleaning the surface of the silicon wafer using hydrogen fluoride (HF), and a second step of replacing the hydrogen fluoride (HF) used in the first step with pure water. Process, the second
And the third step of forming a chemical oxide film on the surface of the silicon wafer by continuously replacing the pure water used in the step (b) with a dilute solution of hydrogen peroxide solution. .

Further, in the pretreatment method for forming a gate insulating film according to the present invention, the first to third steps are performed in one processing layer 105. That is, in the present invention, it is necessary that the surface of the silicon wafer is configured not to be exposed to the atmosphere at least during the execution of the first to third steps. is there.

In performing the pretreatment method for forming a gate insulating film according to the present invention, as shown in FIG. 1, the silicon wafer 110 carried out from the clean room 101 for the above-described processing is applied to the silicon wafer 110. It is desirable to perform a pre-cleaning step for removing the deposits attached to the surface of the silicon wafer 110. More specifically, a chemical substance capable of forming a chemical oxide film, for example, NH ₄ OH / H ₂ O
_A first pre-cleaning step of cleaning the silicon wafer with ₂ / H ₂ O and a _second pre-cleaning step of cleaning the chemical substance capable of forming a chemical oxide film with pure water,
It is desirable that it is provided before.

More specifically, the one bath cleaning tank 10
Before the first step performed in step 5, a 0th step which is a pre-cleaning step for removing deposits adhered to the surface of the silicon wafer is provided. Is a first pre-cleaning step of cleaning the silicon wafer with a chemical substance capable of forming a chemical oxide film, and a second pre-cleaning step of cleaning the chemical substance capable of forming a chemical oxide film with pure water. Preferably, the first pre-cleaning step is performed in the first cleaning tank 103 and the second pre-cleaning step is performed.
The pre-cleaning step is desirably configured to be performed in the second cleaning tank 104.

Further, in the method for pretreatment of forming a gate insulating film according to the present invention, the above-described one bath cleaning tank 105 is provided.
It is preferable that a drying step for drying the surface of the silicon wafer is further provided subsequent to the third step in the step (b).
It is executed in.

In the drying step in the present invention, it is preferable that isopropyl alcohol (IPA) is used for pure water, and in the drying step, an isopropyl alcohol (IPA) film layer is formed on the pure water layer. It is desirable that the treatment be performed so as to form.

Next, another specific embodiment of the present invention will be described. In other words, there is no water mark obtained by the above-described embodiment, and a uniform oxide film covered with a chemical oxide film is used. It is necessary to remove the chemical oxide film in order to form a desired gate insulating film having a thickness of, for example, 3.0 nm or less on a silicon wafer having an unexposed silicon surface. The present invention relates to a gate insulating film forming pretreatment method for removing a chemical oxide film and an apparatus therefor. That is, such processing operation is executed using an apparatus as shown in FIG. That is, in this specific example, after the drying tank 106, the silicon wafer 110 is further transferred into the ultrahigh vacuum chamber 501,
An oxide film detachment processing unit 108 for increasing the temperature of the silicon wafer 110 and detaching the oxide film formed in the diluted hydrogen peroxide solution is provided.

More specifically, after the drying process in this embodiment, the silicon wafer 110 is further
The silicon wafer 110 is transferred into an ultra-high vacuum chamber 501 provided in the oxide film detachment processing unit 108.
Of the oxide film formed in the diluted hydrogen peroxide solution is carried out, and the degree of vacuum in the ultra-high vacuum chamber is 5 degrees.
It is preferably at most 10 ^-8 Torr. Further, in this specific example, the temperature of the silicon wafer when removing the oxide film formed in the diluted solution of hydrogen peroxide solution is 900 to 1000 ° C., and the processing time is 10 min. It is desirable to be within.

The outline of the structure of the oxide film detachment processing section 108 in the above embodiment of the present invention will be described below with reference to FIG.

The oxide film separation processing section 108 includes a sample processing chamber 501, a heater chamber 502, and an exchange chamber 503, and a plurality of wafers 507 can be stored in the exchange chamber. A gate valve 504 is provided between the sample processing chamber 501 and the exchange chamber 507, and each chamber is evacuated by exhaust systems 511, 512, 513 constituted by a plurality of pumps. The sample processing chamber 501 and the exchange chamber 50
7 and a wafer transfer mechanism 505 for moving the wafer 110.
Is provided. By taking such a configuration,
The wafer 110 can be exchanged and moved without exposing the sample processing chamber 501 to the atmosphere. An ECR plasma source 506 for generating oxygen radicals and gas supply systems 521 to 524 are attached to the sample processing chamber 501. Further, a heater 508 for heating the wafer 110 is attached to the heater chamber 502, so that the substrate temperature of the silicon wafer can be heated up to 1200 degrees. The gas supply system includes an oxygen gas cylinder 521, stop valves 522 and 524, a mass flow controller 52
The oxygen gas is introduced into the sample processing chamber 501 through an ECR plasma source. The oxygen gas to be introduced is adjusted by the mass flow controller.
It can be controlled in the range of × 10 ^{-4 to 5} Torr. By adopting the above-described apparatus configuration, it is possible to perform an annealing process in an ultra-high vacuum required for a pre-process for forming a gate insulating film, and to realize the pre-processing conditions of the present invention. That is, the sample processing chamber is set to an ultra-high vacuum atmosphere of 5 × 10 ⁻⁸ Torr or less, and the substrate temperature is set to 900 to 10 by a heater.
00 degrees, 0.5-5 min. The treatment removes the oxide film formed in the diluted hydrogen peroxide solution and the contamination such as organic substances adhered on the oxide film during drying / transportation, thereby forming an ultra-clean surface of silicon.

Incidentally, in the sample processing chamber 501 of the oxide film detachment processing section 108 in this embodiment, in addition to the treatment for detaching the chemical oxide film formed on the silicon wafer surface as described above, Alternatively, it is also possible to perform processing for forming a thin gate insulating film of 3.0 nm or less on the surface of the silicon wafer from which the chemical oxide film has been removed.

In the following, the above-mentioned specific example according to the present invention will be described in more detail. First, a schematic view of a sample used in the above-mentioned gate insulating film forming pretreatment method according to the present invention will be described. Is shown in FIG.

That is, in an experiment for verifying the effect of the gate insulating film formation pretreatment method according to the present invention and confirming appropriate manufacturing conditions, p-type silicon (100), ρ =
A sample in which an element isolation region 605 was previously formed on a silicon substrate 604 of 0.02 Ωcm was used. After forming a thermal oxide film on the silicon surface, the device isolation 605 covers a silicon nitride film serving as a mask for selectively oxidizing the device isolation region, and the silicon nitride film is formed only in the device region by patterning. Leave, introduce the same type of impurity as the substrate silicon into the element isolation region,
A thick oxide film 605 was formed in the element isolation region.

First, particles are removed in the APM cleaning tank 103. The chemical at this time is H ₂
O: H ₂ O ₂ : NH ₄ OH = 20: 6: 1, and a treatment was performed at 65 ° C. for 5 minutes. Note that megasonic treatment was used in combination to enhance the particle removal effect. Next, in order to wash away the APM cleaning liquid, the pure water cleaning tank 104 is used.
For 5 minutes. Subsequently, hydrogen fluoride (HF) treatment, pure water cleaning, and peroxide dilution solution treatment are performed in the one bath cleaning tank 105. In the one bath cleaning tank 105, first, in order to remove an oxide film formed during the APM cleaning, the substrate was immersed in a mixed solution of hydrogen fluoride (HF): H ₂ O = 1: 30 for 45 seconds. After removing the oxide film, the hydrogen fluoride (HF) solution is replaced with pure water in the same tank, and then the pure water is replaced with a hydrogen peroxide diluted solution. If the hydrogen fluoride (HF) component remains, the oxide film formed by the diluted solution of hydrogen peroxide is etched again, so it is necessary to completely replace the hydrogen fluoride (HF) solution with pure water. It is. Here, 30 pure water
L / min. By flowing hydrogen fluoride (H
F) The solution was removed. In order to replace pure water with a diluted solution of hydrogen peroxide, the concentration of hydrogen peroxide is 1.5 wt%.
At 10 L / min. Run for 5 minutes. In a diluted solution of hydrogen peroxide solution, further 5 min. , And finally, washing with pure water at 30 L / min. This was performed for 2 minutes, and the diluted hydrogen peroxide solution was washed away.

When the process in the one bath cleaning tank 105 is completed, the wafer is transferred to the IPA drying processing tank 106.
FIG. 5 shows the state of the wafer contact part. Atmosphere when washing with water
Replace with PA vapor 402 and liquefy IP on pure water tank 404
By forming the A layer 403, the surface of the wafer 401 becomes as shown in FIG. 5 regardless of whether the surface is hydrophilic or hydrophobic. The waste liquid speed is 1 L / min. The surface tension 405 of water acts in a direction to separate the particles 406 and water droplets, and the wafer surface is dried. As described above, when the processing in the wet cleaning apparatus is completed, the wafer is subjected to the ultra-high vacuum processing oxide film forming apparatus UHV of the oxide film detachment processing unit 108 described above.
(Ultra High Vacuum).

In the present embodiment, the wafer subjected to the cleaning / drying treatment was annealed at a pressure in the UHV oxide film forming apparatus of 1 × 10 ⁻⁹ Torr or less. At this time, the temperature and the processing time are 900 ° C., 5 min. And

Thereafter, as shown in FIGS. 6 and 7, the sample is formed with a gate oxide film 606 while maintaining the temperature at 750 ° C. Then, while maintaining the sample temperature at 650 ° C., disilane is flowed at 10 sccm to form a gate electrode. Was deposited.

For the gate oxide film 607, oxygen gas was introduced into the ultrahigh vacuum chamber at 1.0 × 10 ⁻³ Torr, and a microwave (μ) wave power of 150 W was applied. This allows
Radical oxide film 606 on exposed silicon Si clean surface
Was formed.

In Example 1, a sample was then taken out into the atmosphere to form a MOS-FET transistor. The MOS-FET transistor has a gate electrode p-S
After forming a source / drain region 608 by attaching a sidewall 611 to a side wall of the i607, titanium is deposited on the entire surface by sputtering to form a silicon layer exposed on the source / drain and the gate electrode as shown in FIG. By reacting with titanium, titanium silicide layers 609 and 610 were formed, and unreacted titanium was removed in a wet solution. Thereafter, a contact hole was formed, and wiring was performed using aluminum.

By the above method, ultra-thin oxide films having various thicknesses of 3.0 nm or less were formed to produce MOS-FET transistors. When the electrical characteristics of the MOS-FET transistor were examined, as shown in FIG. 9, no abnormal leakage current flowed for a thin oxide film having a thickness of up to 1.0 nm.
It has been confirmed that the transistor operates normally. That is,
As is clear from FIG. 9, the leakage current value in the semiconductor device according to the present invention decreases as the thickness of the gate insulating film increases, and the leakage current value is reduced by the conventional method at any thickness. It is understood that the leakage current value is smaller than the leakage current value in the gate insulating film. Further, when the interface state density was examined by capacitance-voltage measurement, 1 × 10 ¹⁰ /
It was about eV · cm ² .

The electrical characteristics of the semiconductor device formed according to the above-described embodiment are shown by the relationship between the variation of the threshold voltage and the thickness of the gate insulating film. FIG. 11 shows the result of analysis in comparison with the semiconductor device having the above. That is, as apparent from FIG. 11, in a semiconductor device having a gate insulating film manufactured by a conventional method, when the film thickness is changed to 1.0 to 3.0, the threshold value is changed. Voltage fluctuation is 0.08 ~
Although it varies between 0.3 (V), in a semiconductor device having a gate insulating film formed by using the pretreatment method according to the present invention, the film thickness is 1.0 to 3.0. When the threshold voltage is changed to 0.0 to 0.1
It is understood that the change only occurs during (V).

From these results, it has been found that the electrical characteristics of the semiconductor device manufactured according to the present invention are greatly improved as compared with the conventional semiconductor device. In other words, the semiconductor device according to the present invention has a source diffusion layer and a drain diffusion layer formed on the surface of a silicon substrate and an inner layer thereof, and a surface of the silicon substrate opposed to a channel region formed between the two diffusion layers. A semiconductor device comprising a formed gate insulating film and a gate electrode formed on the gate insulating film, wherein the gate insulating film has a thickness of 1.0
The semiconductor device is characterized in that the variation of the threshold voltage in the semiconductor device is in the range of 0 V to 0.1 V.

The pretreatment method for forming a gate oxide film described in the above specific example of the present invention has the following structure.
Since a watermark does not occur in principle and an oxide film can be formed on a clean surface, it is possible to form a gate insulating film having excellent electrical characteristics and a thickness of 3.0 nm or less.

Next, another specific example of the pretreatment method for forming a gate insulating film according to the present invention will be described in detail below.

That is, in this embodiment, the concentration of the diluted hydrogen peroxide solution in the above-described embodiment is 3 to 0.3 watts.
t% treatment time is 1 to 60 min. Thus, a comparison with the above specific example was performed. The conditions of the cleaning step other than the concentration of the diluted hydrogen peroxide solution and the processing time were all the same as the conditions in the specific example.

For each concentration, the relationship between the oxide film thickness formed in the solution and the time was examined. Figure 1 shows the results.
0 is shown. In other words, the growth rate of the oxide film increases as the concentration increases, and the film thickness increases with the processing time.

Next, watermarks were observed for the samples treated at each concentration. The observation of the watermark was performed by performing an annealing process in an ultra-high vacuum, flowing disilane, and epitaxially growing silicon on the surface. Oxide film that causes watermark,
If there is contamination, pits (holes) cannot be formed on the silicon due to the epitaxial growth, and the watermark can be easily observed with an optical microscope.

Hereinafter, the observation results will be described. Watermarks were observed regardless of treatment time when the concentration was higher than 1.5 wt%. This is presumably because the concentration was too high and the substitution with pure water was not uniform, and as a result, a uniform oxide film could not be formed on the wafer. In addition, a watermark was also generated for a sample having a long processing time and a film thickness of more than 1.0 nm. This is probably because the oxide film was too thick, and the annealing treatment in vacuum (900 ° C., 5 min.) Was insufficient, so that the oxide film remained on the surface without being desorbed.

On the other hand, when the concentration is lower than 0.6 wt%,
Alternatively, a watermark was generated even for an oxide film having a short processing time and a film thickness of 0.3 nm or less. this is,
This is probably because the oxide film was thin and the wafer surface was not completely hydrophilic. When the concentration is lower than 0.6 wt%, the processing time is further increased and the thickness of the oxide film is reduced to 0.3%.
Although it is considered that the watermark can be eliminated by setting the thickness to nm or more, it is not practical because the processing time is one hour or more.

The MOS-FET transistor having the gate oxide film formed under the condition that the watermark is generated has an increased leakage current and does not operate as a transistor as compared with the MOS-FET transistor according to the process described in the above embodiment. Was.

From the above results, as a condition for eliminating the generation of the watermark, the concentration of the hydrogen peroxide solution is preferably 1.5 wt% or less in order to uniformly replace the pure water.
An oxide film of 0.3 to 1.0 nm is coated for 60 min. 0.6 wt% or more is preferable in order to form within.

Next, as another specific example, an experiment was conducted by changing the pressure, temperature, and processing time as follows for the annealing conditions in the ultra-high vacuum chamber 501 in the first specific example. Was done. Note that the sample preparation conditions immediately before performing the annealing were all the same as those in the first specific example.

The pressure in the ultra-high vacuum chamber 501 was changed in the range of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁷ Torr, and annealing was performed at 900 ° C. for 5 minutes. Subsequently, processing was performed by the method described in the above specific example so that the watermark could be observed with an optical microscope. As a result, 5 × 10 ^-9 to 1 × 10 ^-7 Torr
All samples annealed in the range of r produced a watermark. It is considered that this is because the detached oxide film adhered to the surface again due to the low degree of vacuum, or contamination in the chamber adhered to the surface.

Next, at a vacuum degree of 1 × 10 ⁻⁹ Torr or less, the annealing temperature is 800 to 1100 ° C., and the processing time is 0 to 10 min. Was changed within the range. Subsequently, processing was performed by the method described in the above specific example so that the watermark could be observed with an optical microscope. As a result, all the samples processed at a temperature lower than 900 ° C. produced a watermark. This is probably because the oxide film formed in the solution could not be completely eliminated. Also,
With respect to the sample processed at 1000 ° C. or higher, although no watermark was generated, a sample in which the shape of the element isolation end was broken appeared. This is probably because the high annealing temperature promoted the elimination reaction of the oxide film at the element isolation end.

As described above, in order to completely desorb the oxide film formed in the diluted hydrogen peroxide solution and perform the annealing process without losing the shape of the element isolation end, the processing temperature is 900 ° C.
A range of -1000 degrees is preferred. The processing time is
The thickness value of the oxide film (0.3 to 1.0 n
m).

A short-time treatment is preferable to protect the element isolation end. When the substrate temperature is 900 ° C., 10 minutes. , A processing time of less than 1 minute at 1000 degrees is preferred.

A MOS-FET transistor having a gate oxide film formed under a condition in which a watermark is generated or a condition in which an element isolation end shape is broken is compared with a MOS-FET transistor according to the process described in the first embodiment. As a result, the leakage current increased and the transistor did not operate.

As described above, the degree of vacuum, the processing temperature, and the time were examined by changing the annealing conditions. As a result, the degree of vacuum during annealing is 5 × 10 5 in order to maintain the cleanliness of the surface.
^-8 Torr or less is appropriate. Further, the processing temperature is required to be 900 ° C. or higher to desorb the oxide film, and is preferably 1000 ° C. or lower to protect the element isolation end. on the other hand,
The processing time needs to be changed depending on the thickness of the oxide film formed in the diluted hydrogen peroxide solution, but a short processing time is preferable in order to protect the element isolation end. Further, in order to desorb the oxide film having a thickness of 0.3 to 1.0 nm or less as described in the above-described specific example, it is necessary to remove 10 mi when the substrate temperature is 900 degrees.
n. , A processing time of less than 1 minute at 1000 degrees is preferred.

[0082]

As described above, by using the present invention, generation of a water mark, which is a problem in the pretreatment method for forming an extremely thin gate insulating film having a thickness of 3.0 nm or less, can be eliminated. Further, by removing contaminants such as organic substances attached to the wafer surface during drying / transfer, a clean surface could be prepared before forming the gate insulating film. As a result, a gate insulating film having a thickness of 3.0 nm or less can be easily formed.
Even in an ultra-thin oxide film region of nm or less, an oxide film with little leakage current could be formed, and thus the electrical characteristics of the semiconductor device could be improved.

[Brief description of the drawings]

FIG. 1 is a schematic plan view illustrating the configuration of a specific example of a pretreatment apparatus for forming a gate insulating film according to the present invention.

FIG. 2 is a block diagram showing a configuration of a specific example of a one-bath cleaning tank used in the pretreatment apparatus for forming a gate insulating film according to the present invention.

FIG. 3 is a cross-sectional view showing a configuration of a specific example of an oxide film detachment processing unit used in the gate insulating film formation pretreatment apparatus according to the present invention.

FIG. 4 is a cross-sectional view illustrating a configuration of a semiconductor device used in a specific example of the silicon wafer pretreatment method according to the present invention.

FIG. 5 is a side view showing the principle of a drying step used in the method for pretreating a silicon wafer according to the present invention.

FIG. 6 is a sectional view showing a manufacturing process of a semiconductor device used in a specific example of the silicon wafer pretreatment method according to the present invention.

FIG. 7 is a cross-sectional view showing a manufacturing process of a semiconductor device used in a specific example of the silicon wafer pretreatment method according to the present invention.

FIG. 8 is a sectional view showing a manufacturing process of a semiconductor device used in a specific example of the method for pretreating a silicon wafer according to the present invention.

FIG. 9 is a graph showing gate leakage current characteristics of a MOS-FET manufactured by the silicon wafer pretreatment method according to the present invention in comparison with a conventional semiconductor device.

FIG. 10 is a graph showing a relationship between an oxide film thickness and time in a semiconductor device manufactured by the silicon wafer pretreatment method according to the present invention.

FIG. 11 is a graph showing electrical characteristics of a semiconductor device manufactured by a method for pretreating a silicon wafer according to the present invention in relation to a semiconductor device obtained by a conventional method. is there.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 gate oxide film forming apparatus 101 clean room 102 cleaning apparatus 103 first cleaning tank 104 second cleaning tank 105 one-bath cleaning tank 106 drying tank 108 chemical oxide film separation processing unit 110 silicon wafer 120 ... Cleaning tank main body part 121 Double bottom part 122 Mesh part 130 Receiving part part 160 Thick waste liquid line 170 Dilute waste liquid line 180 Hydrogen fluoride (HF) supply part 181 Hydrogen fluoride (HF) supply line 190 ... Hydrogen peroxide aqueous solution supply section 191 ... Hydrogen peroxide supply line 200 ... Pure water supply section 201 ... Pure water supply line 213,215,217 ... Valve section 220,221 ... Flow meter 222 ... Mixing means 301 ... Processing liquid introduction unit 302: waste liquid line 303: waste liquid discharge unit 401: silicon wafer 402: IPA vapor 4 3 Liquefied IPA layer 404 Pure water 405 Particles 406 Surface tension 501 Ultra-high vacuum chamber 502 Substrate heating chamber 503 Preparation chamber 504 Gate valve 505 Transfer rod 506 Plasma source 507 Silicon wafer 508 ... heater 511, 512, 513 ... exhaust system 521 ... oxygen gas 522 ... valve 523 ... mass Flow controller 524 ... valve 604 ... silicon (100) substrate 605 ... CVD SiO ₂ film 606 ... gate oxide film 607 ... p-Si Gate electrode 608: Source / drain region 609: Titanium silicide layer formed on source / drain region 610: Titanium silicide layer formed on gate electrode 611: Side wall

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5F040 DA19 DC01 EC01 EC04 EC07 EC13 EH02 EJ03 EK01 FC00 FC02 FC19 5F045 AA09 AB32 AC01 AC11 AF03 BB14 BB16 EB13 EB14 EN04 HA01 HA04 HA06 HA23 5F058 BA20 BC02 BE03 BE10 BF08 BF08 BF08 BF08BF69 BG04 BJ01

Claims (22)

[Claims] When a gate oxide film is formed on a silicon wafer, hydrogen fluoride (HF) is added to the silicon wafer.
First, the surface of the silicon wafer is cleaned using
A second step of replacing the hydrogen fluoride (HF) used in the first step with pure water, and replacing the pure water used in the second step with a diluted hydrogen peroxide solution. And a third step of forming a chemical oxide film on the surface of the silicon wafer by performing the replacement step continuously. 3. A method of pretreating a silicon wafer when a gate oxide film is formed on the silicon wafer. 2. The method according to claim 1, wherein the first to third steps are performed in one processing layer. 3. The method according to claim 1, wherein the surface of the silicon wafer is not exposed to the atmosphere at least during the execution of the first to third steps. Or the pretreatment method for forming a gate insulating film according to 2. 4. The method according to claim 1, further comprising, before the first step, a 0th step, which is a pre-cleaning step for removing the deposits attached to the surface of the silicon wafer. 4. The pretreatment method for forming a gate insulating film according to any one of 1 to 3. 5. The first step is a first pre-cleaning step of the silicon wafer with a chemical substance capable of forming a chemical oxide film, and a second pre-cleaning step of cleaning the chemical substance capable of forming a chemical oxide film with pure water. 5. The pretreatment method for forming a gate insulating film according to claim 4, comprising a step of: 6. The gate insulating film according to claim 1, further comprising a drying step of drying the surface of the silicon wafer subsequent to the third step. Processing method. 7. The method according to claim 6, wherein the drying step uses pure water as isopropyl alcohol (IPA). 8. The pretreatment method for forming a gate insulating film according to claim 7, wherein said drying step includes forming an isopropyl alcohol (IPA) film layer on said pure water layer. 9. The concentration of the diluted solution of hydrogen peroxide in water is set at 0.1.
9. The composition according to claim 1, wherein the content is 6 to 1.5 wt%.
The gate insulating film formation pretreatment method according to any one of the above. 10. The treatment time in said hydrogen peroxide solution is 5 hours.
~ 60 min. The pretreatment method for forming a gate insulating film according to claim 1, wherein: 11. An oxide film for transferring the silicon wafer into an ultra-high vacuum chamber after the drying step, raising the temperature of the silicon wafer, and removing the oxide film formed in the diluted hydrogen peroxide solution. The method according to any one of claims 6 to 10, wherein a separation step is provided. 12. The method according to claim 11, wherein the degree of vacuum in the ultra-high vacuum chamber is 5 × 10 ⁻⁸ Torr or less. 13. The temperature of said silicon wafer when desorbing an oxide film formed in said dilute solution of hydrogen peroxide is 900 to 1000 ° C., and the processing time is 10 min. 13. The pretreatment method for forming a gate insulating film according to claim 11, wherein: 14. An apparatus for forming a gate oxide film on a silicon wafer, wherein hydrogen fluoride (HF) is supplied to at least the silicon wafer in a cleaning apparatus provided adjacent to a clean room holding the silicon wafer. A first step of cleaning the surface of the silicon wafer using the first step;
A second step of replacing the hydrogen fluoride (HF) used in the first step with pure water, replacing the pure water used in the second step with a diluted hydrogen peroxide solution, A gate insulating film for forming a gate oxide film on a silicon wafer, wherein a one-bath cleaning tank is provided for continuously performing a third step of forming a chemical oxide film on the surface of the silicon wafer; Pre-processing equipment. 15. The one-bath cleaning tank is configured so that the surface of the silicon wafer is not exposed to the atmosphere while the first to third steps are performed. 15. The pretreatment apparatus for forming a gate insulating film according to claim 14, wherein: 16. A first cleaning for executing a first pre-cleaning step using a chemical substance capable of forming a chemical oxide film in order to remove deposits attached to the surface of the silicon wafer. A tank, a second cleaning tank for performing a second pre-cleaning step of cleaning the chemical substance capable of forming a chemical oxide film with pure water, the one-bath cleaning tank, and a drying tank. 16. The pretreatment apparatus for forming a gate insulating film according to claim 14, wherein: 17. The one-bath cleaning tank includes a cleaning tank main body for holding the silicon wafer, a processing liquid introduction unit and a processing liquid discharge unit connected to a bottom of the cleaning tank main body, and a cleaning bath main unit. Hydrogen fluoride (HF) individually connected to the receiving portion for receiving the overflowed processing liquid, a waste liquid discharging portion provided at the bottom of the receiving portion, and the processing liquid introducing portion via individual valves. 17. The pretreatment apparatus for forming a gate insulating film according to claim 14, further comprising a supply unit, a hydrogen peroxide solution diluted solution supply unit, and a pure water supply unit. 18. The pretreatment apparatus for forming a gate insulating film according to claim 17, wherein the processing liquid introduction section and the individual valve sections are individually connected via mixing means. 19. A flow meter is provided between the processing liquid introduction unit, the hydrogen fluoride (HF) supply unit, the hydrogen peroxide solution dilution solution supply unit, and the pure water supply unit. 19. The pretreatment apparatus for forming a gate insulating film according to claim 17, wherein: 20. The cleaning tank according to claim 14, wherein the bottom portion of the cleaning tank main body portion is formed of a double bottom portion, and a mesh portion is formed at a partition portion of the double bottom portion.
9. The pretreatment apparatus for forming a gate insulating film according to any one of 9 above. 21. After the drying tank, the silicon wafer is further transferred into an ultra-high vacuum chamber, the temperature of the silicon wafer is increased, and an oxide film formed in a diluted hydrogen peroxide solution is desorbed. 21. The pretreatment apparatus for forming a gate insulating film according to claim 14, further comprising a film detachment processing section. 22. A gate insulating film formed on the surface of the silicon substrate opposed to a channel region formed between the source and drain diffusion layers formed on the surface of the silicon substrate and its inner layer, and between the two diffusion layers. A gate electrode formed on the gate insulating film, wherein the gate insulating film has a thickness of 1.0 nm to 1.0 nm.
A semiconductor device having a thickness of 3.0 nm and a variation in threshold voltage of the semiconductor device in a range of 0 V to 0.1 V;