JP3350215B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Cleaning a crystal surface in a semiconductor device manufacturing process has a very large effect on the quality of a semiconductor device obtained. For example, in the case of a silicon (Si) crystal surface, residual impurities such as a natural oxide film, organic contaminants, and heavy metals existing on the surface may hinder high-quality Si epitaxial growth at a low temperature, or a thin film gate. It acts as a factor that hinders high-precision control of the oxide film, increases a series resistance in the formation of a metal ohmic contact, and degrades rectification characteristics, etc., and causes a process hindrance and a device performance degrade. Therefore, it is essential to form a clean crystal surface free of residual impurities.

[0003] As a method for cleaning the surface of the Si crystal, a method of heating at a high temperature of about 800 to 1000 ° C in vacuum after performing organic cleaning or acid cleaning for the purpose of removing organic substances and natural oxide films is widely used. ing. Although this method is reliable, it is not easy to keep it stable except in a high vacuum because the cleaning surface is very active.

On the other hand, dry etching using a chemical reaction can be applied only to removal of an oxide film, but since heavy metals cannot be sufficiently removed, it is indispensable to use wet pretreatment together.

[0005] A typical example of the above-mentioned technique is removal of an oxide film on the crystal surface by hydrogen fluoride (HF) cleaning and subsequent hydrogen termination of the outermost surface Si. The surface of the Si crystal cleaned by this method is subsequently confirmed to be stable in the atmosphere by Res. Soc. Symp. Proc. 259
(1992) 409. However, it is a well-known fact that surface contamination proceeds reliably if left in the air, which is inconvenient. Further, in a normal semiconductor device manufacturing process, it is necessary to perform a rinsing process using pure water after HF cleaning.
It is known that the surface of the i-crystal is oxidized and contaminated.

Incidentally, the oxide film thickness on the crystal and the surface composition of carbon and oxygen are determined by XPS (X-ray Photoe).
By using electron spectroscopy, more detailed evaluation can be performed. Using this XPS evaluation, after HF cleaning, the oxide film thickness and the surface composition of the surface of the Si substrate rinsed with pure water having a dissolved oxygen concentration of about several ppm, which is generally used, are examined. It can be seen that the oxide film of-is present immediately after the rinsing. Although these are almost no problem in a semiconductor device of about 1 μm rule, they have an adverse effect as the design rule becomes finer and the integration becomes higher. Oxidation of the Si crystal surface progresses as the rinsing time elapses. For these reasons, there is a demand for a processing method capable of cleaning the surface of a Si crystal or the like and maintaining the clean state in order to improve the performance of the semiconductor device.

On the other hand, a processing solution containing hydrogen fluoride is also used for a flattening process of a Si substrate. For example, Si (11
1) Regarding the substrate surface, buffered hydrofluoric acid (B
An HF) solution treatment, a boil treatment in pure water after treatment with HF, and the like are performed, and flattening at an atomic level is realized. In addition, it has been reported that the flattened surface of a Si (100) substrate surface can be obtained by a treatment using a BHF solution (pH = 5.3).

However, in such a flattening process, for example, in a BHF solution process, it is a condition that no pure water rinsing is performed thereafter, and in the case of a hydrogen fluoride process, pure water rinsing must be performed at a high temperature. There was a problem in the safety and stability of the manufacturing process. For these reasons, there is a need for a processing technique that can easily and safely planarize the surface of a Si substrate.

By the way, a recent 0.1 μm rule CMO
In the case of S, the thickness of the gate oxide film is several nm.
The thickness of the oxide film of the tunnel oxide film of the ROM is required to be extremely small, about 7 to 10 nm. In such a thin oxide film, the irregularities on the Si surface are transmitted similarly to the irregularities after the oxide film is formed. MOS gate breakdown voltage is S
It depends on the roughness of the i-surface, and the higher the flatness of the surface is, the more uniform the gate breakdown voltage is. Also EEPROM
As for the reliability of the semiconductor device, the flattening of the tunnel oxide film alleviates the concentration of the electric field and improves the withstand voltage of the electric field. In view of the above, there is a strong demand for a safe and simple technology for flattening the Si substrate surface at the atomic level.

[0010]

As described above, although a technique for cleaning a crystal surface typified by the surface of a Si substrate has been studied, there are technical areas in which the degree of cleaning is insufficient with the conventional cleaning technique. In addition to the appearance, it has been difficult to maintain the cleaned surface in that state as seen in the increase of the oxide film after the cleaning and the adsorption of carbon and oxygen. Since these hinder favorable crystal growth on the crystal surface and the like, it is desired to solve the above problems in order to manufacture a semiconductor device with higher performance.

On the other hand, the conventional planarization technology for Si substrates has problems in terms of safety and stability. Therefore, there is a demand for a safe and simple planarization technology on the Si substrate surface at the atomic level.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made to further clean and flatten the crystal surface of a semiconductor and to maintain the state, thereby forming an oxide film formed on the crystal surface. It is an object of the present invention to provide a method of manufacturing a semiconductor device in which an interface with the semiconductor device can be cleaned.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a surface treatment step for cleaning a semiconductor crystal surface of a semiconductor substrate, and flattening the semiconductor crystal surface after the surface treatment step. A method of manufacturing a semiconductor device, comprising: a liquid cleaning step of performing a liquid cleaning step; and an oxidation step of forming an oxide film on the surface of the semiconductor crystal subsequent to the liquid cleaning step.

The surface treatment used in the cleaning step includes a liquid surface treatment agent, for example, hydrofluoric acid, pure water, sulfuric acid, hydrochloric acid, hydrogen peroxide, ammonia, or a combination thereof. And the like.

The liquid used in the cleaning step is preferably a liquid that does not substantially oxidize the semiconductor substrate. Specifically, pure water having a dissolved oxygen concentration of 300 ppb or less is used.

It is known that as the concentration of dissolved oxygen in pure water is reduced, the formation rate of an oxide film formed on the crystal surface of the substrate decreases. And, for example, Si (10
When the dissolved oxygen concentration is extremely low, such as 300 ppb or less, with respect to the 0) plane, oxidation can be suppressed so as not to occur. In this case, since the surface of the crystal is terminated with hydrogen, adhesion of surface contaminants such as carbon and oxygen can be suppressed.
Therefore, the surface of the clean crystal subjected to the surface treatment can be maintained even after rinsing with pure water. This state hardly depends on the time for immersing the semiconductor substrate in pure water for at least about one week.

In the case of the Si (111) surface, the effect is obtained even when the dissolved oxygen concentration is about 1 ppm or less. The use of such low-concentration pure water also contributes to planarization of the crystal surface. Although the surface of the Si crystal treated with a liquid surface treatment agent containing hydrofluoric acid or the like is terminated with hydrogen, the surface smoothness is not sufficient when viewed at the atomic level.

FIG. 1 shows a simple schematic diagram of the Si crystal surface in this state. As shown in the figure, micro-roughness such as steps 12 and facets 13 exists on the surface of the Si crystal 11.

FIG. 2 shows the state of Si atoms terminated with hydrogen by HF treatment or the like. Si bonded to hydrogen 21
The bonding force 24 between the atom 22 and the internal Si atom 23 is weaker than the bonding force 25 between the hydrogen 21 and the Si atom 22. On the other hand, an OH ^- group 26 exists in pure water at 10 ^-7 mol / L, and the OH ^- group 26 enters between the Si bonds 24 and has an effect of etching the Si atoms 22 on the outermost surface. However, if the concentration of dissolved oxygen in pure water is high, for example, about 9 ppm, of the Si atoms 22 on the outermost surface, step 1 in FIG.
Second part is oxidized faster than the progress of the etching OH ^-
The effect of the base 26 cannot be fully obtained.

On the other hand, when the dissolved oxygen concentration is 300 ppb
When the following pure water is used, the oxidation of the crystal surface is suppressed, so that the etching effect by the OH ^- group 26 can be sufficiently exhibited. And this OH ^- group 26
1 mainly occurs at the step 12 in FIG. 1, so that the surface of the Si crystal can be flattened even by pure water rinsing at about room temperature.

That is, in the conventional rinsing with pure water containing high concentration of dissolved oxygen, the interaction between the surface of the Si crystal and the pure water, which has been hindered by the formation of an oxide film, is reduced to a concentration of 300 ppb or less. The use of pure water makes it possible to surely generate water. As a result, the surface of the crystal can be planarized by etching the Si crystal with pure water.

For example, when represented by the center line average roughness _Ra (DIN 4768, JIS B 0601), which is a measure of smoothness, according to the flattening treatment according to the present invention, pure water having a dissolved oxygen concentration of 300 ppb or less is used. The value of _Ra = 0.1 nm or less by processing alone is 100 × 100 nm ²
This can be achieved in the above areas.

As described above, the surface of the crystal can be reliably cleaned by suppressing the formation of an oxide film and the attachment of surface contaminants such as oxygen and carbon, while at the same time achieving the planarization at the device size. Therefore, good crystal growth and improvement of the electrical characteristics of the interface can be realized, and a higher-performance semiconductor device can be obtained.

Incidentally, when compared with the Si (100) plane, Si (1
11) The surface has higher tolerance to dissolved oxygen,
Even at about pm or less, there is a sufficient effect. In the above, the example using pure water has been described.
A similar etching effect can be obtained by using a H-adjusted hydrofluoric acid-based solution or a boiled pure water.

A step of forming an oxide film is performed successively to the above-described cleaning step. Here, “continuously” refers to forming an oxide film while maintaining the liquid in the liquid used in the cleaning step or by replacing the liquid without removing the liquid from the liquid.

The liquid which can be used in this step is pure water, sulfuric acid + hydrogen peroxide system, hydrofluoric acid + hydrogen peroxide system,
It is an oxidizing agent for Si such as hydrochloric acid + hydrogen peroxide.
Whichever liquid is used, an oxide film is formed on the Si surface without removing the semiconductor substrate from the liquid after the cleaning step.

Even when the semiconductor substrate is taken out of the liquid, the oxide film is removed after temporarily placing the semiconductor substrate in an atmosphere of an inert gas which does not cause contamination such as oxygen and carbon on the surface of Si at a surface density of not less than%. By performing the forming step, the same effect as in the case of continuously forming an oxide film can be obtained.

Here, vacuum, high-purity hydrogen gas, nitrogen gas, argon gas, helium gas or the like can be used as the inert gas. For example, if pure water is used also in the step of forming an oxide film using pure water in the cleaning step, the liquid used in the cleaning step and the step of forming the oxide film are the same, so that replacement of the liquid is not performed. You can On the other hand, in the case where pure water is used in the cleaning step and sulfuric acid + hydrogen peroxide is used in the step of forming an oxide film, the semiconductor surface is cleaned by replacing the liquid without removing the semiconductor substrate from the liquid. The oxide film can be formed while keeping the state. In other words, by removing the semiconductor substrate from the liquid in order to perform oxidation after the cleaning step as in the related art, it is possible to prevent the surface of the crystal cleaned in the cleaning step from being contaminated.

The concentration of oxygen to be added may be high enough to form an oxide film, specifically, 300 ppb to 9 ppb.
pm is preferred. When an oxide film is formed in this way, 1
An oxide film of about 2 nm is formed. Since a recent gate oxide film of CMOS requires an oxide film of several nm, and a tunnel oxide film of EEPROM requires an oxide film of about 7 to 10 nm, a method similar to the conventional method is used after the step of forming an oxide film according to the present invention. Oxidation to obtain a thickness of an oxide film required for the semiconductor device.

At this time, the interface between the oxide film formed by the process of forming the oxide film of the present invention and the oxide film formed by the conventional process is contaminated. However, this contamination is 20% or more in XPS evaluation as compared with the contamination generated at the interface between the crystal surface of the semiconductor and the oxide film, which is contaminated when the oxide film is formed only by the conventional oxide film forming process. It turned out to be less.

Furthermore, the contamination at the interface between the oxide film and the oxide film according to the present invention contributes to the performance of the semiconductor device to a lesser extent than the conventional contamination at the interface between the crystal surface of the semiconductor and the oxide film. In other words, the interface between the crystal surface of the semiconductor and the oxide film, which is important in determining the performance of the semiconductor device, is kept clean by using the oxide film forming step of the present invention. And a high-performance semiconductor device can be obtained.

[0032]

According to the present invention, a step of cleaning the surface of a semiconductor substrate with a liquid after the surface treatment is performed, and a step of forming an oxide film is performed continuously from this step. The interface between the crystal surface of the semiconductor and the oxide film is further cleaned and flattened as compared with a semiconductor device that performs the process.

[0033]

Embodiments of the present invention will be described below. First, FIG. 3 schematically shows a configuration of a processing apparatus according to an embodiment to which a method of manufacturing a semiconductor device according to the present invention is applied. In the figure, reference numeral 31 denotes a processing vessel having a drain tube 33 at a lower portion,
The drain pipe 33 has a valve 32 on its way. The processing container 31 is made of a low-elution material such as quartz or a Teflon-based resin such as PVDF or PFA. The processing vessel 31 is sealed by a lid 34 made of a similar material.
Is connected. The introduction pipe 35 has a valve 32 in the middle. An oxygen introduction pipe 36 having an oxygen introduction valve 37 in the middle is connected to the upper part of the introduction pipe 35.

Inside the processing container 21, a liquid surface treatment agent 38, such as pure water
Hydrofluoric acid-based, sulfuric acid-based, hydrochloric acid-based, hydrogen peroxide-based, ammonia-based, or a combination of these is added. Then, a semiconductor substrate 39, for example, a Si crystal substrate is put therein, and residual impurities on the surface of the crystal, for example, an oxide film and organic contaminants are removed. Next, the valve 32 is opened and pure water having a dissolved oxygen concentration of 300 ppb or less is supplied to the processing vessel 31.
After the replacement with the liquid surface treatment agent 38, the surface of the semiconductor substrate 39 is washed with the introduced pure water.

After the cleaning with pure water, the oxygen introduction valve 37 is opened to introduce oxygen into the processing vessel 31 to increase the oxygen concentration in the pure water, thereby forming an oxide film on the surface of the semiconductor substrate 39.

A 6-inch p-Si (100) substrate having a specific resistance of 25 to 50 Ω · cm was processed using the processing apparatus having the above-described configuration according to the above-described procedure. 2 for processing solution
% HF aqueous solution and pure water having a dissolved oxygen concentration of 300 ppb or less were used.

In this pure water rinsing, the flow rate is 0.5 c
In the case of m / s, not only the oxide film is not formed even after 15 minutes, but also oxidation does not occur even after 5000 hours. This effect is almost the same up to a dissolved oxygen concentration of 300 ppb.

On the Si (111) plane, the same effect can be obtained at 1 ppm or less. Next, FIG. 4 shows the relationship between the standard deviation (RMS) of surface roughness and the dissolved oxygen concentration when the Si (100) substrate was treated with an HF aqueous solution and then rinsed with pure water in which only the dissolved oxygen concentration was changed. Show. In the figure, the horizontal axis represents dissolved oxygen concentration, and the vertical axis represents RMS. The dissolved oxygen concentration in pure water is 300 ppb or less, more specifically, 20 ppb
At 0 ppb or less, oxidation of the Si surface is suppressed and
It can be seen from this figure that etching occurs and as a result the surface flatness is improved and the RMS is reduced.

Similar effects can be obtained for the Si (111) plane. As an example of manufacturing a semiconductor device to which the above-described processing method is applied, an example of manufacturing a 0.1 μm rule CMOS will be described. FIG. 5 shows the manufactured 0.1 μm rule NMO.
It is sectional drawing which shows the structure of S.

First, a LOCOS oxide film 52 was formed on a Si (100) substrate 51. Next, after removing the oxide film on the surface corresponding to the film-forming surface of the Si (100) substrate 51 with an HF-based solution, a rinse treatment is performed with pure water having a dissolved oxidation concentration of 30 ppb or less to obtain a clean and flat Si surface 51a having excellent flatness. Formed.

Next, on the Si surface 51a, a thickness of about 1 n
In order to form the gate oxide film 53a of m, oxygen was introduced into pure water to increase the oxygen concentration to 4 ppm. Then S
The i-substrate 51 was kept in pure water so as not to be exposed to the atmosphere.

Thereafter, the Si substrate 51 is taken out of the pure water, and a gate oxide film 53b having a thickness of about 4 nm is formed by wet oxidation, and the thickness of the gate oxide film 53 is set to about 5 nm.
It was made to become.

Here, the gate oxide film 53b may be formed by using dry oxidation instead of wet oxidation. Subsequently, source 54, drain 55, gate electrode 56, source
A source electrode 57 and a solein electrode 58 were formed.

FIG. 6 shows the relationship between the dissolved oxygen concentration and the gate pressure resistance when the dissolved oxygen concentration in the pure water in the pure water rinse is changed. In the figure, the horizontal axis represents the dissolved oxygen concentration, and the vertical axis represents the gate breakdown voltage. After the pure water rinse shown by the solid line, S
A gate oxide film 53a is formed without exposing the Si substrate 51 to the air after rinsing with pure water, as indicated by a broken line, as compared with a case where the gate oxide film 53 is formed by exposing the i-substrate 51 to the atmosphere, In the case of the present embodiment in which the gate oxide film 53b is formed thereafter, the improvement of the breakdown voltage by about 10% can be seen.

Further, the region treated with pure water having a dissolved oxygen concentration of up to 5 ppm has a low gate voltage and a dissolved oxygen concentration of 3 ppm.
It can be seen that the gate voltage increases from 00 ppb or less, more specifically, from about 200 ppb or less. Further 0.1
It can be seen that in order to obtain a gate voltage corresponding to a μm rule CMOS semiconductor device, it is best to treat with pure water having a dissolved oxygen concentration of 30 ppb or less.

As already reported, when micro roughness such as a terrace is small on the Si surface due to planarization, when a voltage is applied to the NMOS gate, the electric field concentration is reduced and the gate voltage is reduced. Uniformity can be achieved, and uniformity of element characteristics and improvement of yield can be expected.

In the case of (111) CMOS, 1 pp
This effect appears below m. In a normal MOS structure, S
An i (100) substrate is often used. This is (100)
This is because the number Nit of dangling bonds per unit area is smaller than other plane orientations, which is advantageous from the viewpoint of reliability against electric field stress.

In the operation state of the MOS, hot electrons and hot holes jump into the gate oxide film. The dangling bond breaks during this dive, which leads to a decrease in reliability. At this time, Si (100)
If there are irregularities on the surface, (11) besides the (100) plane
1) It means that the plane orientation and the like exist, and it cannot be said that it is an ideal (100) plane. That is, (111)
Since the surface and the like have more Nit than the (100) surface, the (100) surface having more irregularities than the ideal (100) Nit has a large number of dangling bonds and lowers the reliability.

As described above, it is possible to improve the reliability by improving the flatness of the surface of the Si substrate. Next, FIG. 7 shows the breakdown electric field strength of the oxide film formed on the Si substrate 51. In the figure, the horizontal axis represents the concentration of residual carbon at the Si-oxide film interface, and the vertical axis represents the breakdown electric field strength. After rinsing with pure water, the Si substrate 51 is exposed to the atmosphere to form a gate oxide film 53.
In this embodiment, as compared with the case where
The residual carbon concentration at the interface between the substrate and the gate oxide film 53a is about 1%
It can be seen that as a result of the reduction below, the breakdown electric field strength is improved.

FIG. 8 shows another configuration example of the processing apparatus to which the present invention is applied. 8, the same parts as those in FIG. 3 are given the same numbers. The difference from the processing apparatus of FIG.
4 is connected to a pure water introduction pipe 35 and a nitrogen introduction pipe 81 having a valve 82 in the middle.

In such a processing apparatus, as in the processing apparatus shown in FIG. 3, a semiconductor substrate 39 and a liquid surface treating agent 38 are first put in a processing vessel 31 in advance.
The impurities remaining on the surface of the semiconductor substrate 39 are removed. Next, after opening the valve 82 and introducing high-purity nitrogen from the nitrogen introduction pipe 81, the valve 32 is opened and pure water is introduced. By supplying pure water with nitrogen introduced in this way, pure water having a dissolved oxygen concentration of 300 ppb or less can be produced on the spot.

The decrease in the dissolved oxygen concentration can be explained by Henry's law. Henry's law means that the concentration of dissolved oxygen in a liquid is proportional to the partial pressure of oxygen in the gas in contact with the liquid. By utilizing this, the dissolved oxygen concentration can be reduced to 300 ppb or less by setting the oxygen concentration in nitrogen in the processing container 31 to 399 Pa or less. Processing container 3
By setting the oxygen concentration in nitrogen within 1 to 13.3 Pa or less, the dissolved oxygen concentration can be reduced to the order of 10 ppb.

FIG. 9 shows still another configuration example of a processing apparatus to which the present invention is applied. In FIG. 9, the same parts as those in FIG. 8 are given the same numbers. 8 is different from FIG.
1 is that it has entered the inside of the processing container 31.

In the processing apparatus shown in FIG.
When the flow rate of pure water into the solution is high, the escape rate of oxygen from the liquid may not be sufficiently ensured, and the concentration of dissolved oxygen may not be reduced to a required level. In this case, it is necessary to increase the contact area between nitrogen and pure water. For example, by performing nitrogen bubbling as shown in FIG. 9, the contact area between nitrogen and pure water can be intentionally increased. Thereby, the dissolved oxygen concentration can be reduced.

It should be noted that other gases such as argon, hydrogen, helium gas and the like can be used in place of nitrogen as long as the oxygen concentration in the gas is equal to or less than the above-described concentration.

FIG. 10 shows another configuration example of the processing apparatus. In FIG. 10, the same parts as those in FIG. 3 are given the same numbers. The feature of this device is that a vacuum exhaust device 101 is connected to the lid 34.

The reason why the vacuum exhaust device 101 is provided is to reduce the concentration of dissolved oxygen by reducing the pressure of the atmosphere in contact with the surface treatment agent 38 and the surface of pure water by the vacuum exhaust device 101. Also in this case, the oxygen concentration in the vacuum is 39
By setting the pressure to 9 Pa or less, the dissolved oxygen concentration can be reduced to 300 ppb or less.

FIG. 11 shows another embodiment of the processing apparatus. In the figure, reference numeral 111 denotes a processing vessel having a drain tube 113 at a lower portion, and the drain tube 113 has a valve 112 in the middle thereof. Further, an introduction pipe 114 of pure water or the like is connected to the processing container 111, and the processing apparatus has a double structure in which an external container 115 is disposed outside the processing container 111. A lid 117 to which a nitrogen introduction pipe 116 is connected is disposed above the processing container 111 and the external container 115. The nitrogen introduced from the nitrogen introduction pipe 116 is
17 so as to be accumulated once and flow out uniformly. The peripheral portion 117a of the lid 117 causes also flows out to the outer peripheral portion 117a of the introduced nitrogen, air is mixed into the processing unit by the pressure and the unidirectional flow of nitrogen in the lid 117 such as oxygen or C _x H _y The semiconductor substrate is prevented from being contaminated by the contaminants.

Inside the processing vessel 111, a liquid surface treating agent 38 selected in advance according to the processing content, for example, pure water, hydrofluoric acid, sulfuric acid, hydrochloric acid, hydrogen peroxide, ammonia, or a combination thereof Put the adjusted one. A semiconductor substrate 39 such as Si
A crystal substrate is put in, and residual impurities on the surface of the crystal, such as an oxide film and organic contaminants, are removed. Next, the pure water introduction pipe 11
4, pure water having a dissolved oxygen concentration of 300 ppb or less is introduced into the processing container 111 to replace the liquid surface treating agent 38, and then the surface of the semiconductor substrate 39 is washed with the introduced pure water.

In this cleaning step, the nitrogen introducing pipe 116 is used.
By introducing more nitrogen and setting the atmosphere in the processing apparatus to nitrogen, an increase in the concentration of dissolved oxygen in pure water can be suppressed, and oxidation of the surface of the semiconductor substrate 39 can be completely suppressed. For example, when 5 ppb of pure water is used, the dissolved oxygen concentration can be suppressed to 10 ppb or less.

After the cleaning with pure water, the nitrogen introduction pipe 11
6, oxygen is introduced into the processing vessel 111 in place of nitrogen to increase the oxygen concentration in the pure water, so that the semiconductor substrate 3
An oxide film is formed on the surface of the substrate 9.

FIG. 12 shows another configuration example of the processing apparatus. 12, the same parts as those in FIG. 10 are given the same numbers. 10 is different from FIG. 10 in that the processing container 121 can be divided into two parts by an O-ring 122, the introduction pipe 35 of pure water or the like, and the evacuation device 1
01 is integrated into one introduction pipe 123 in front of the processing container, and this introduction pipe has a valve 124 in the middle.
The advantage of such a configuration is that the degree of vacuum in the processing container 121 is further increased by the O-ring 122.

[0063]

As described above, according to the present invention, the crystal surface of the semiconductor is further cleaned and flattened to maintain the state, and the interface with the oxide film formed on the crystal surface is normal. It is possible to provide a method for manufacturing a semiconductor device which can be made into a semiconductor device.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a state of a surface of a Si substrate after being treated with an HF-based solution.

FIG. 2 is a diagram schematically showing a state of a surface of a Si substrate terminated with hydrogen with an HF-based solution.

FIG. 3 is a diagram schematically showing a configuration of a processing apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram showing the standard deviation of the surface roughness of a Si substrate when rinsed with pure water having various dissolved oxygen concentrations.

FIG. 5 is a cross-sectional view illustrating a configuration of an NMOS formed in an example of the present invention.

FIG. 6 is a diagram showing the relationship between the dissolved oxygen concentration in pure water and the gate breakdown voltage of the NMOS produced in the embodiment of the present invention.

FIG. 7 is a diagram showing the breakdown electric field strength of an NMOS oxide film formed in an example of the present invention.

FIG. 8 is a diagram schematically showing a configuration of a processing apparatus according to another embodiment of the present invention.

FIG. 9 is a diagram schematically showing a configuration of a processing apparatus according to another embodiment of the present invention.

FIG. 10 is a diagram schematically showing a configuration of a processing apparatus according to another embodiment of the present invention.

FIG. 11 is a diagram schematically showing a configuration of a processing apparatus according to another embodiment of the present invention.

FIG. 12 is a diagram schematically showing a configuration of a processing apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 31, 111, 121 ... processing vessel 32, 37, 82, 112, 124 ... valve 33, 113 ... drain pipe 34, 117 ... lid 35, 114 ... pure water introduction pipe 36 ... oxygen introduction pipe 38 ... liquid surface treatment agent 39 ... Semiconductor substrate 81,116 ... Nitrogen introduction tube 101 ... Vacuum exhaust device 122 ... O-ring 123 ... Introduction tube

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-29293 (JP, A) JP-A-5-29307 (JP, A) JP-A-1-150328 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 21/304 H01L 21/306 H01L 21/316

Claims (5)

(57) [Claims] A semiconductor crystal surface of a semiconductor substrate is cleaned.
Surface treatment step, and flattening the semiconductor crystal surface after the surface treatment step.
A liquid cleaning step, and an oxide film on the semiconductor crystal surface following the liquid cleaning step.
Characterized by comprising an oxidation step of forming a semiconductor layer.
Device manufacturing method. 2. The surface of a semiconductor substrate is cleaned with a hydrofluoric acid-based solution.
Surface treatment process, and the surface of the semiconductor substrate cleaned in the surface treatment process
A pure water cleaning step of etching and flattening with water, and oxidizing the surface of the semiconductor substrate following the pure water cleaning step
An oxidation process for forming a film.
Manufacturing method of body device. 3. The method according to claim 1, wherein the flattening is performed at a dissolved oxygen concentration of 300 pp.
b. It is performed by washing with pure water not more than b.
A method for manufacturing a semiconductor device according to claim 1 or claim 2.
Law. 4. The method according to claim 1, wherein the flattening is performed at a dissolved oxygen concentration of 30 ppb.
It is performed by the following pure water cleaning
A method for manufacturing a semiconductor device according to claim 1. 5. The method according to claim 1, wherein the flattening is performed at a dissolved oxygen concentration of 10 ppb.
It is performed by the following pure water cleaning
A method for manufacturing a semiconductor device according to claim 1.