JPH10303310A - Formation of gate electrode in semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a gate electrode with silicon oxide films having different thicknesses, a high initial breakdown voltage and an excellent long-term reliability, while avoiding a significant increase in the number of manufacturing steps. SOLUTION: In the method, a silicon oxide film 42 is first formed on a silicon layer 40 (step 1). A first conductive layer 43 is formed on the film 42 (step 2). Thereafter, the first conductive film 43 is selectively removed to expose part of the film 42 (step 3). The exposed silicon oxide film 42 is then made thin in thickness (step 4). The thin film is subjected to a heat treatment (step 5). A second conductive layer is formed on the resultant entire film and then the second layer and the first conductive layer 43 are subjected to a patterning process (step 6).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gate formed of a first semiconductor device and a silicon oxide film having a thickness different from that of a silicon oxide film forming a gate electrode of the first semiconductor device. The present invention relates to a method for manufacturing each gate electrode in a semiconductor device including a second semiconductor element provided with an electrode.

[0002]

2. Description of the Related Art Higher integration, higher performance, and diversification of semiconductor devices are being promoted year by year, and requirements regarding the characteristics of semiconductor devices are also being diversified. For example, even if a voltage is supplied from the same power supply to a plurality of transistor elements formed in an integrated circuit, a voltage drop occurs due to an internal resistance or the like of the circuit. As a result, the voltage applied to the gate electrode of each transistor element differs,
There are cases where a transistor element operating at a certain voltage and a transistor element operating at a lower voltage are divided. Therefore, for example, if the transistor element is a MOS type FE
In the case of using T, it is desirable to change the thickness of the gate insulating film according to the voltage applied to the gate electrode of the transistor element. Specifically, for example, the thickness of a gate insulating film is changed between a transistor element forming a memory circuit of a semiconductor device and a transistor element forming a peripheral circuit, or between a p-channel transistor element and an n-channel transistor element. It is desirable to make it.
Thus, one of the recent demands for semiconductor devices is:
A technique for forming gate oxide films having different thicknesses with high reliability and without significantly increasing the number of steps for manufacturing a gate electrode in a semiconductor device can be given.

A first semiconductor device and a second semiconductor device having a gate electrode formed of a silicon oxide film having a thickness different from that of a silicon oxide film forming a gate electrode of the first semiconductor device. A conventional method for manufacturing a gate electrode of a semiconductor device including elements will be described below with reference to FIGS. 17 and 18 which are schematic partial cross-sectional views of a silicon semiconductor substrate and the like. The region of the silicon semiconductor substrate on which the first semiconductor element is to be formed is shown on the right side of each drawing,
The region of the silicon semiconductor substrate on which the semiconductor element is to be formed is shown on the left side of each figure.

First, as shown in FIG. 17A, first silicon is formed on a surface of an element formation region of a silicon semiconductor substrate 110 in which an element isolation region 111 having a LOCOS structure is formed by a thermal oxidation method. An oxide film 112A is formed. Next, using the patterned resist 113 as an etching mask (see FIG. 17B), the first silicon oxide film 1 is formed using, for example, an aqueous hydrofluoric acid solution.
12A is selectively removed to expose a part of the silicon semiconductor substrate 110 (see FIG. 17C). afterwards,
The resist 113 is removed (see FIG. 17D), and a second silicon oxide film 112B is formed on the exposed surface of the silicon semiconductor substrate 110 by a thermal oxidation method (see FIG. 18A). At this time, the thickness of the first silicon oxide film 112A remaining on a part of the surface of the element formation region of the silicon semiconductor substrate 110 is increased. Thus, an element formation region having the thick silicon oxide film 112A and an element formation region having the thin silicon oxide film 112B can be provided in the silicon semiconductor substrate 110.

After that, each of the silicon oxide films 112A, 112
For example, a polycrystalline silicon layer 114 is formed on the 2B by a CVD method, and the polycrystalline silicon layer 114 is patterned to form a first semiconductor element for the first semiconductor element composed of the silicon oxide film 112A and the polycrystalline silicon layer 114. A first gate electrode and a second gate electrode for a second semiconductor element including the silicon oxide film 112B and the polycrystalline silicon layer 114 can be manufactured (see FIG. 18B). After that, a first transistor element and a second transistor element each including the first gate electrode and the second gate electrode as components are manufactured by a known method.

In such a conventional method of manufacturing a gate electrode in a semiconductor device, as shown in FIG. 17B, a resist 1 is formed on a first silicon oxide film 112A.
13 must be formed. Usually, the resist 113 is made of a cinnamic acid-based resist material or a rubber-based resist material. However, these resist materials contain a large amount of alkali metals and heavy metals, and the resist 113 is formed on the first silicon oxide film 112A. Is directly formed, contamination occurs in the first silicon oxide film 112A. as a result,
Problems such as deterioration of the initial breakdown voltage of the silicon oxide film 112A and long-term reliability of the breakdown voltage occur.

[0007]

A technique for solving such a problem is disclosed, for example, in Japanese Patent Laid-Open No. 4-103162. According to this technology, for example, LO
On the surface of the element formation region of the silicon semiconductor substrate 110 where the element isolation region 111 having the COS structure is formed (FIG.
9A), a first silicon oxide film 112A is formed by a thermal oxidation method (see FIG. 19B). Then
After forming a first polycrystalline silicon layer 120 on the entire surface (see FIG. 19C), the first polycrystalline silicon layer 12 is formed.
Then, a patterned resist 121 is formed on the resist pattern 0.
Then, using the resist 121 as an etching mask,
The first polycrystalline silicon layer 120 and the first silicon oxide film 112A are selectively removed, and the silicon semiconductor substrate 11 is removed.
After exposing a part of 0, the resist 121 is removed (see FIG. 19D and FIG. 20A). afterwards,
As shown in FIG. 20B, a second silicon oxide film 112B is formed on the exposed surface of the silicon semiconductor substrate 110 by a thermal oxidation method. According to this method, the resist 121 is not directly formed on the first silicon oxide film 112A, so that contamination of the first silicon oxide film 112A due to the resist 121 does not occur.

However, in this method, when the second silicon oxide film 112B is formed on the surface of the silicon semiconductor substrate 110 exposed by the thermal oxidation method,
Silicon oxide film 1 also on the surface of polycrystalline silicon layer 120 of FIG.
12C is formed (see FIG. 20B). Then, since second polysilicon layer 122 is formed on silicon oxide film 112C (see FIG. 20C), the silicon oxide film formed on the top surface of first polysilicon layer 120 is formed. 112C and the second formed thereon
Of the polysilicon layer 122 must be selectively removed. Therefore, in the method disclosed in this patent publication, there is a problem in that the number of manufacturing steps of the gate electrode in the semiconductor device is increased.

Accordingly, an object of the present invention is to provide a gate comprising a first semiconductor element and a silicon oxide film having a thickness different from that of a silicon oxide film constituting a gate electrode of the first semiconductor element. A gate electrode in a semiconductor device including a second semiconductor element provided with an electrode can be manufactured without increasing the number of manufacturing steps to the left;
Moreover, it is an object of the present invention to provide a method capable of forming a silicon oxide film having excellent initial withstand voltage and long-term reliability of withstand voltage.

[0010]

In order to achieve the above object, a method for manufacturing a gate electrode in a semiconductor device according to the present invention comprises a first semiconductor element and a silicon layer forming the gate electrode of the first semiconductor element. A method of manufacturing each gate electrode in a semiconductor device comprising: a second semiconductor element having a gate electrode formed of a silicon oxide film having a thickness different from the thickness of the oxide film; Forming a silicon oxide film on the surface; (b) forming a first conductive layer on the silicon oxide film; and (c) selectively removing the first conductive layer to form a silicon oxide film. (D) reducing the thickness of the exposed silicon oxide film, (e) subjecting the thinned silicon oxide film to a heat treatment, and (f) covering the entire surface. After forming the second conductive layer, Patterning the second conductive layer and the first conductive layer, made of, than Te, silicon oxide film,
A gate electrode for a first semiconductor device composed of a first conductive layer and a second conductive layer, and a second semiconductor device composed of a thinned silicon oxide film and a second conductive layer For producing a gate electrode.

In the method of manufacturing a gate electrode in a semiconductor device according to the present invention, the heat treatment in the step (e) is preferably performed in an atmosphere of an inert gas containing a halogen element. By heat-treating the silicon oxide film in an inert gas atmosphere containing a halogen element, it is possible to remove contamination generated in the thinned silicon oxide film and to remove and repair defects. Alternatively, if necessary, after forming a silicon oxide film on the surface of the silicon layer in step (a), and before forming the first conductive layer on the silicon oxide film, (Hereinafter, such a heat treatment may be referred to as a preliminary heat treatment). Note that the heat treatment and the preliminary heat treatment may be hereinafter collectively referred to as a heat treatment or the like. When performing the preliminary heat treatment, it is desirable that the atmosphere of the preliminary heat treatment be an inert gas atmosphere containing a halogen element. By performing a heat treatment or the like on the silicon oxide film in an atmosphere of an inert gas containing a halogen element, silicon dangling bonds (Si.) And Si-OH, which are defects that may be generated in the silicon oxide film, are combined with the halogen element. As a result, silicon dangling bonds are terminated or a dehydration reaction occurs. As a result, these defects which are reliability deterioration factors are eliminated, and silicon excellent in time zero dielectric breakdown (TZDB) characteristics and time-dependent dielectric breakdown (TDDB) characteristics is obtained. An oxide film can be obtained. Examples of the halogen element include chlorine, bromine, and fluorine, and among them, chlorine is preferable. Examples of the form of the halogen element contained in the inert gas include hydrogen chloride (HCl), CCl ₄ ,
It can be exemplified _{C 2 HCl 3, Cl 2,} HBr, NF 3. The content of the halogen element in the inert gas is 0.001 to 10% by volume, based on the form of the molecule or compound,
Preferably it is 0.005 to 10% by volume, more preferably 0.02 to 10% by volume. For example, when using hydrogen chloride, the content of hydrogen chloride in the inert gas is 0.02 to 10
Desirably, it is volume%. The temperature of these heat treatments is 700-1200 ° C., preferably 700-1200 ° C.
000 ° C, more preferably 700-950 ° C. In addition, the time of the heat treatment and the like is 5 to 60 minutes, preferably 10 to 40 minutes in the case of a batch method using a furnace annealing method.
More preferably, it is 20 to 30 minutes. On the other hand, in the case of a single-wafer type rapid high-temperature annealing method, it is preferable to set the time to 1 to 10 minutes. Examples of the inert gas in the heat treatment and the like include a nitrogen gas, an argon gas, and a helium gas.

The heat treatment or the like may be performed in a state in which the atmosphere of an inert gas containing a halogen element is reduced in pressure from the atmospheric pressure. The pressure in the heat treatment or the like is 1.3 × 10 ⁴ Pa (1
00 Torr) or less. The lower limit of the pressure depends on an apparatus for performing a heat treatment or the like on the silicon oxide film, but is preferably as low as possible.

After the heat treatment in the step (e), the silicon oxide film may be nitrided. In this case, the nitriding treatment is preferably performed in an N ₂ O gas, NO gas, or NO ₂ gas atmosphere, and particularly preferably in an N ₂ O gas atmosphere. Alternatively, the nitriding treatment is performed using NH ₃ gas, N ₂
H ₄ , hydrazine derivative atmosphere, then N ₂ O
It is desirable to perform the annealing treatment in a gas or O ₂ atmosphere. 700-1200 ° C., preferably 8
00 to 1150 ° C, more preferably 900 to 11
Preferably, the heating is performed at a temperature of 00 ° C. In this case, the heating of the silicon layer is preferably performed by infrared irradiation and furnace annealing.

Alternatively, the atmosphere for the heat treatment in the step (e) may be a nitrogen-based gas atmosphere. Here, N ₂ , NH ₃ , N ₂ O, and NO ₂ can be exemplified as the nitrogen-based gas.

In the method for fabricating a gate electrode in a semiconductor device according to the present invention, the formation of the silicon oxide film on the surface of the silicon layer in the step (a) is performed at (A) a temperature at which silicon atoms are not desorbed from the surface of the silicon layer. A first silicon oxide film forming step of forming a silicon oxide film on the surface of the silicon layer by an oxidation method using a wet gas while maintaining the atmosphere; and (B) a first silicon oxide film forming step A second silicon oxide film forming step of further forming a silicon oxide film by an oxidation method using a wet gas in an atmosphere higher than the ambient temperature in.

Usually, before forming a silicon oxide film on a silicon layer, the silicon layer is washed with an aqueous solution of NH ₄ OH / H ₂ O ₂ and further washed with HC
The surface of the silicon layer is cleaned by RCA cleaning in which the silicon layer is cleaned with a 1 / H ₂ O ₂ aqueous solution, fine particles and metal impurities are removed from the surface, and the silicon layer is immersed in a hydrofluoric acid aqueous solution. By the way, when a silicon semiconductor substrate whose surface is exposed with an aqueous solution of hydrofluoric acid is carried into a high-temperature wet gas atmosphere or a nitrogen gas atmosphere, the surface of the silicon layer may be roughened. This phenomenon is caused by the fact that Si-H bonds and some Si-F bonds formed on the surface of the silicon layer by washing with a hydrofluoric acid aqueous solution are lost due to thermal desorption of hydrogen or fluorine, and the silicon layer This is due to an etching phenomenon occurring on the surface. When the temperature of the silicon semiconductor substrate is raised to 600 ° C. or more in argon gas, severe irregularities may occur on the surface of the silicon semiconductor substrate.
It is described in page 21 of "Ultra Clean ULSI Technology" by Tadahiro Omi, published by Baifukan. By performing the first silicon oxide film forming step while maintaining the atmosphere at a temperature at which silicon atoms do not desorb from the surface of the silicon layer, it is possible to suppress the occurrence of such roughness on the surface of the silicon layer. Can be.

The temperature at which silicon atoms do not desorb from the surface of the silicon layer in the step of forming the silicon oxide film is preferably a temperature at which the bond between the atoms terminating the silicon layer surface and the silicon atoms is not broken. In this case, the temperature at which silicon atoms do not desorb from the surface of the silicon layer is the temperature at which Si—H bonds are not broken or S
It is preferable that the temperature be such that the i-F bond is not broken.
The temperature at which silicon atoms do not desorb from the surface of the silicon layer is a value measured at 1.013 × 10 ⁵ Pa (1 atm), and is equal to or higher than the temperature at which the wet gas does not condense on the silicon layer, preferably It is desirable that the temperature be 300 ° C. or higher.

The oxidation method using a wet gas in the step (A) and / or the step (B) includes a pyrogenic oxidation method,
It is preferable to use at least one oxidation method among the oxidation method using steam generated by heating pure water and the oxidation method using steam generated by bubbling heated pure water with an oxygen gas or an inert gas. When a silicon oxide film is formed by an oxidation method using a wet gas, a silicon oxide film having excellent time-dependent dielectric breakdown (TDDB) characteristics can be obtained. In the oxidation method using a wet gas, the wet gas may be diluted with an inert gas.

The wet gas in the step (A) and / or the step (B) may contain a halogen element. As a result, a silicon oxide film having excellent time zero dielectric breakdown (TZDB) characteristics and temporal dielectric breakdown (TDDB) characteristics can be obtained. In addition, chlorine, as a halogen element,
Bromine and fluorine can be mentioned, and among them, chlorine is desirable. Examples of the form of the halogen element contained in the wet gas include hydrogen chloride (HCl), C
Cl ₄ , C ₂ HCl ₃ , Cl ₂ , HBr and NF ₃ can be mentioned. The content of the halogen element in the wet gas is 0.001 to 10% by volume, preferably 0.005 to 10% by volume, more preferably 0.02 to 10% by volume, based on the form of the molecule or the compound. . For example, when using hydrogen chloride, the hydrogen chloride content in the wet gas is 0.02 to 1
Desirably, it is 0% by volume.

The thickness of the silicon oxide film after the step (B) may be a predetermined thickness required for a semiconductor device. On the other hand, the thickness of the silicon oxide film after the step (A) is preferably as thin as possible. However, the plane orientation of a silicon semiconductor substrate currently used for manufacturing a semiconductor device is almost always (100), and no matter how smooth the surface of the silicon semiconductor substrate is, the surface of the silicon semiconductor substrate must be (100). A step called a step is formed. This step is usually for one layer of silicon atoms, but in some cases, a step for two to three layers may be formed. Therefore, the thickness of the silicon oxide film after the step (A) is preferably 1 nm or more when a (100) silicon semiconductor substrate is used as the silicon layer.

From the ambient temperature in step (A), the ambient temperature for forming the silicon oxide film may be temporarily lowered to, for example, room temperature, and then raised to the ambient temperature in step (B). And the temperature in the step (B) is increased from the ambient temperature in step (B) to the ambient temperature in step (B), and the atmosphere in the temperature raising step may be a reduced-pressure atmosphere, an inert gas atmosphere, or an oxidizing atmosphere containing a wet gas. preferable. Here, examples of the inert gas include a nitrogen gas, an argon gas, and a helium gas. Note that the inert gas or the wet gas in the atmosphere in the temperature raising step may contain a halogen element. Thereby, the characteristics of the silicon oxide film formed in the step (A) can be further improved. That is, a silicon dangling bond (Si.) Or Si—OH, which is a defect that can be generated in the step (A), reacts with a halogen element in the temperature raising step, and the silicon dangling bond terminates or a dehydration reaction occurs. These defects, which are the factors that deteriorate the properties, are eliminated. Especially,
Elimination of these defects is effective for the initial silicon oxide film formed in the step (A). In addition, as the halogen element, chlorine, bromine and fluorine can be mentioned, and among them, chlorine is preferable. As the form of the halogen element contained in the inert gas or the wet gas, for example, hydrogen chloride (HCl), CCl ₄ , C ₂
HCl ₃ , Cl ₂ , HBr and NF ₃ can be mentioned. The content of the halogen element in the inert gas or wet gas is 0.00% based on the form of the molecule or compound.
1 to 10% by volume, preferably 0.005 to 10% by volume,
More preferably, the content is 0.02 to 10% by volume. For example, when hydrogen chloride is used, the content of hydrogen chloride in the inert gas or wet gas is preferably 0.02 to 10% by volume.

When the preliminary heat treatment is performed subsequent to the step (B), the ambient temperature at the time of performing the preliminary heat treatment on the formed silicon oxide film is higher than the ambient temperature at the time of forming the silicon oxide film in the step (B). It can be taken as a form. In this case, after the formation of the silicon oxide film in the step (B) is completed, the atmosphere is switched to an inert gas atmosphere,
Next, the temperature may be raised to the ambient temperature for performing the preliminary heat treatment, but it is preferable to switch the atmosphere to an inert gas atmosphere containing a halogen element and then raise the temperature to the ambient temperature for performing the preliminary heat treatment. . Also, the process (e)
When the heat treatment is performed on the silicon oxide film thinned in the above, the atmosphere for raising the temperature to the heat treatment temperature may be an inert gas atmosphere, but the atmosphere is preferably an inert gas atmosphere containing a halogen element. Here, as the form of the halogen element contained in the inert gas,
For example, hydrogen chloride (HCl), CCl ₄ , C ₂ HCl ₃ ,
Cl ₂ , HBr and NF ₃ can be mentioned. The content of the halogen element in the inert gas is 0.001 to 10% by volume, preferably 0.005 to 10% by volume, more preferably 0.02 to 1% by volume, based on the form of the molecule or the compound.
0% by volume. For example, when using hydrogen chloride, the content of hydrogen chloride in the inert gas is preferably 0.02 to 10% by volume.

In the step (A), before forming the silicon oxide film, the atmosphere maintained at a temperature at which silicon atoms are not desorbed from the surface of the silicon layer is formed before the formation of the silicon oxide film based on the wet gas. In order to suppress the formation of the silicon oxide film, it is desirable to use an inert gas atmosphere or a reduced pressure atmosphere.

Instead of using a wet gas in step (A) and / or step (B), an oxidizing gas containing no water vapor can be used. Examples of the oxidizing gas containing no water vapor include oxygen gas and oxygen gas containing hydrochloric acid. In the oxidation method using an oxidizing gas, the oxidizing gas may be diluted with an inert gas. In this case, in the first silicon oxide film forming step, before forming the silicon oxide film, the atmosphere maintained at a temperature at which silicon atoms are not desorbed from the surface of the silicon layer is a silicon oxide film based on an oxidizing gas. In order to suppress the formation of the silicon oxide film before the formation, it is desirable to use an inert gas atmosphere or a reduced pressure atmosphere.

The method of forming the silicon oxide film in the steps (A) and (B) may be the same oxidation method or different oxidation methods. Further, the formation of the silicon oxide film in the steps (A) and (B) may be performed by the same silicon oxide film forming apparatus, or may be performed by different silicon oxide film forming apparatuses. The silicon oxide film forming apparatus may be either a batch type or a single wafer type. In the case of performing the preliminary heat treatment, the inside of the silicon oxide film forming apparatus in which the second silicon oxide film forming step of the step (B) is performed, or another batch type or single wafer type annealing apparatus is used. A preliminary heat treatment can be performed.
In Table 1 below, a first silicon oxide film forming step (denoted as a first oxidation step in Table 1) and a second silicon oxide film forming step (denoted as a second oxidation step in Table 1) ), And preferred examples of the treatment method in the preliminary heat treatment step. The first silicon oxide film forming step and the second
In the silicon oxide film forming step and the preliminary heat treatment step,
When a different device is used, it is preferable to transfer the silicon oxide film without exposing the silicon oxide film to the air from the viewpoint of preventing contamination of the surface of the formed silicon oxide film when transferring the silicon layer between the devices. Specifically, the atmosphere during the transfer of the silicon layer is preferably an inert gas atmosphere or a reduced-pressure atmosphere. Here, examples of the inert gas include a nitrogen gas, an argon gas, and a helium gas. In this case, the ambient temperature at the time of transporting the silicon layer may be, for example, room temperature, but from the viewpoint of improving the throughput, the ambient temperature in the first silicon oxide film forming step when the silicon oxide film is formed on the silicon layer Can also be made approximately equal.

[0026]

[Table 1] First oxidation step Second oxidation step Preliminary heat treatment step Batch type Batch type Batch type Batch type Batch type Single wafer type Batch type Single wafer type Batch type Batch type Single wafer type Single wafer type Single wafer type Batch type Batch type Single-wafer type Batch type Single-wafer type Single-wafer type Single-wafer type Batch type Single-wafer type Single-wafer type Single-wafer type

Normally, before forming a silicon oxide film on a silicon layer, the surface of the silicon layer is cleaned by RCA cleaning, and then the silicon layer is immersed in a hydrofluoric acid aqueous solution. However, when the silicon layer is subsequently exposed to the air, the surface of the silicon layer is contaminated, and moisture and organic substances adhere to the surface of the silicon layer, or Si atoms on the surface of the silicon layer combine with hydroxyl groups (OH). (E.g., literature "
Highly-reliable GateOxide Formation for Giga-Scale
LSIs by using Closed Wet Cleaning System and Wet O
xidation with Ultra-Dry Unloading ", J. Yugami, et
al., International Rlectron Device Meeting Technic
al Digest 95, pp 855-858). In such a case,
When the silicon oxide film forming step of step (a) is performed as it is, moisture, an organic substance, or Si—OH is taken into the formed silicon oxide film, and the characteristics of the formed silicon oxide film are deteriorated or It can cause defects. Here, the defect includes a portion of a silicon oxide film including a defect such as a silicon dangling bond (Si.) Or a Si-H bond, or Si-O-Si.
The bond is compressed by stress or the angle of the Si-O-Si bond is thick or S in the bulk silicon oxide film.
Si-OS that is different from the angle of the i-O-Si bond
The portion of the silicon oxide film including the i-bond is included. Therefore, in order to avoid the occurrence of such a problem, the method for manufacturing a gate electrode in a semiconductor device of the present invention includes a step of cleaning the surface of the silicon layer before the step (a). Without exposing the silicon layer to the atmosphere (ie, for example, from the cleaning of the silicon layer surface to the step (a)).
The atmosphere up to the start of the silicon oxide film forming step is an inert gas atmosphere or a vacuum atmosphere, and the step (a) is preferably started. Thus, a silicon oxide film can be formed on the surface of the silicon layer having a clean surface, and the characteristics of the formed silicon oxide film can be prevented from being deteriorated or defects can be prevented. As a method for cleaning the surface of the silicon layer, a method of dipping a silicon oxide film in a hydrofluoric acid aqueous solution, an anhydrous hydrogen fluoride gas vapor atmosphere, a hydrogen chloride gas atmosphere, or a chlorine gas atmosphere (for example, Cl gas atmosphere)
₂ + O ₃ atmosphere).

The first conductive layer and the second conductive layer can be made of, for example, polycrystalline silicon doped with impurities. Alternatively, the second conductive layer may have a two-layer structure (polycide structure) of polycrystalline silicon doped with impurities and silicide such as tungsten silicide.

Here, the silicon layer means not only a substrate itself such as a silicon semiconductor substrate, but also an epitaxial silicon layer, a polycrystalline silicon layer, or an amorphous silicon layer formed on the substrate, so-called bonding method or SIMOX.
Silicon layer in the SOI structure manufactured based on the method,
Further, it means a silicon layer (base) on which a silicon oxide film constituting a gate electrode is to be formed, such as a substrate or a semiconductor element or a component of a semiconductor element formed on these layers. The method of manufacturing the silicon semiconductor substrate is CZ method, MCZ method.
Method, a DLCZ method, an FZ method, etc., or a method in which crystal defects have been removed by performing a high-temperature hydrogen annealing treatment in advance.

According to the method for manufacturing a gate electrode in a semiconductor device of the present invention, for example, a gate electrode of a MOS transistor or a gate electrode of a top gate thin film transistor can be manufactured. Further, the floating gate of the flash memory is also included in the gate electrode in the present invention.

In the method for manufacturing a gate electrode in a semiconductor device according to the present invention, a first conductive layer is formed on a silicon oxide film, and then the first conductive layer is selectively removed to remove the silicon oxide film. Expose the part. Therefore, when exposing a part of the silicon oxide film, there is no need to directly form a resist on the silicon oxide film, so that contamination of the silicon oxide film due to the resist does not occur. In addition, since the thickness of the exposed silicon oxide film is reduced and then the thinned silicon oxide film is subjected to a heat treatment, it is possible to remove contamination caused by the thinning of the silicon oxide film, and to remove and repair defects. As a result, a silicon oxide film having excellent characteristics can be obtained. In addition, since the formation of the silicon oxide film is essentially required only once, the number of steps for manufacturing the gate electrode does not increase as far as the left.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, a method for manufacturing a gate electrode in a semiconductor device according to the present invention will be described below based on embodiments.

Example 1 In Example 1, a silicon oxide film was formed using the vertical silicon oxide film forming apparatus shown in FIG. In Example 1, the silicon layer was formed from a silicon semiconductor substrate. The formed silicon oxide film functions as a gate oxide film. The silicon oxide film was formed by an oxidation method using a wet gas, specifically, a pyrogenic oxidation method. The thinned silicon oxide film was subjected to heat treatment (furnace annealing) in an inert gas atmosphere containing a halogen element (specifically, a nitrogen gas atmosphere containing hydrogen chloride). Hereinafter, a method for manufacturing a gate electrode in the semiconductor device of Example 1 will be described with reference to FIGS. 1 to 5, but before that, an outline of a vertical silicon oxide film forming apparatus will be described. 1 and 2, the region of the silicon semiconductor substrate on which the first semiconductor element is to be formed is shown on the right side of each figure, and the area of the silicon semiconductor substrate on which the second semiconductor element is to be formed is shown on the left side of each figure. Shown in

This vertical silicon oxide film forming apparatus includes a processing chamber 10 having a double tube structure made of quartz, a gas introduction unit 12 for introducing water vapor and the like into the processing chamber 10, and a gas from the processing chamber 10. A gas exhaust unit 13 for exhausting gas, a heater 14 for maintaining the inside of the processing chamber 10 at a predetermined atmospheric temperature via a cylindrical heat equalizing tube 16 made of SiC, and a substrate loading / unloading unit 20.
A gas introduction unit 21 for introducing nitrogen gas into and out of the substrate loading / unloading unit 20, a gas exhaust unit 22 for exhausting gas from the substrate loading / unloading unit 20, and a shutter for separating the processing chamber 10 from the substrate loading / unloading unit 20 15 and the silicon semiconductor substrate in processing chamber 1
It comprises an elevator mechanism 23 for carrying in and out of the vehicle. A quartz boat 24 for mounting a silicon semiconductor substrate is attached to the elevator mechanism 23. Further, the hydrogen gas supplied to the combustion chamber 30 is mixed with the oxygen gas at a high temperature in the combustion chamber 30 and burned to generate steam. Such water vapor is supplied to the pipe 3
1, processing chamber 1 via gas flow path 11 and gas introduction unit 12
It is supplied within 0. The gas flow path 11 is located outside the processing chamber 10 having a double pipe structure.

[Step-100] First, an element isolation region 41 having a LOCOS structure is formed in a silicon semiconductor substrate 40 by a known method, and well ion implantation, channel stop ion implantation, and threshold adjustment ion implantation are performed. Note that the element isolation region may have a trench structure. afterwards,
Wash with aqueous NH ₄ OH / H ₂ O ₂ and further add HCl / H ₂ O ₂
Fine particles and metal impurities on the surface of the silicon semiconductor substrate 40 are removed by RCA cleaning by washing with an aqueous solution, and then the surface of the silicon semiconductor substrate 40 is washed with a 0.1% aqueous hydrofluoric acid solution. The surface is exposed (see FIG. 1A). Most of the surface of the silicon semiconductor substrate is terminated with hydrogen, and part of the surface is terminated with fluorine.

[Step-110] Nitrogen gas is introduced from the gas introduction unit 12 into the processing chamber 10 of the vertical silicon oxide film forming apparatus, and the inside of the processing chamber 10 is set to a nitrogen gas atmosphere. The temperature of the atmosphere in the processing chamber 10 is maintained at 800 to 1000 ° C. by the heater 14. In this state, the shutter 15 is closed (see FIG. 4A). The substrate loading / unloading section 20 is open to the atmosphere. Then, the silicon semiconductor substrate 40 is loaded into the substrate loading / unloading section 20, and the silicon semiconductor substrate 40 is placed on the quartz boat 24. After the loading of the silicon semiconductor substrate 40 into the substrate loading / unloading section 20 is completed, a door (not shown) is closed,
Nitrogen gas is introduced into the substrate loading / unloading section 20 from the gas introduction section 21 and discharged from the gas exhaust section 22 to make the inside of the substrate loading / unloading section 20 a nitrogen gas atmosphere. When the inside of the substrate loading / unloading section 20 becomes a sufficient nitrogen gas atmosphere, the shutter 15 is opened (see FIG. 4B), the elevator mechanism 23 is operated to raise the quartz boat 24, and the silicon semiconductor substrate 40 is lifted.
Is loaded into the processing chamber 10 (see FIG. 5A). When the elevator mechanism 23 reaches the highest position, the processing chamber 10 and the substrate loading / unloading section 20 are not communicated by the base of the quartz boat 24.

Thereafter, the atmospheric temperature in the processing chamber 10 is set to 80
While maintaining the temperature at 0 to 1000 ° C., the hydrogen gas is mixed with the oxygen gas at a high temperature in the combustion chamber 30, and the steam generated by the combustion is supplied through the pipe 31, the gas passage 11 and the gas introduction unit 12. The gas is introduced into the processing chamber 10 and exhausted from the gas exhaust unit 13. As a result, a 20-nm-thick silicon oxide film 42 is formed on the surface of the silicon semiconductor substrate 40 (see FIG. 1B and FIG. 5B). After the formation of the silicon oxide film 42, the inside of the processing chamber 10 is set to a nitrogen gas atmosphere,
The elevator mechanism 23 is operated to lower the quartz boat 24, and then the silicon semiconductor substrate 40 is unloaded from the substrate loading / unloading section 20.

[Step-120] After the silicon oxide film 42 is formed on the surface of the silicon semiconductor substrate 40 corresponding to the silicon layer, the first conductive film having a thickness of, for example, 0.05 μm is formed on the silicon oxide film 42. The layer 43 is formed (see FIG. 1C). The first conductive layer 43 is composed of, for example, a polycrystalline silicon layer doped with an impurity, and has a CV using monosilane gas (SiH ₄ ) as a source gas.
It can be formed by Method D.

[Step-130] Next, the first conductive layer 4
3 is selectively removed to expose a part of the silicon oxide film 42. That is, a patterned resist 44 is formed on the first conductive layer 43 (see FIG. 1D), and the first conductive layer 4 is formed using the resist 44 as an etching mask.
3 is selectively etched. After that, the resist 44 is removed. Thus, the structure schematically shown in FIG. 2A can be obtained.

[Step-140] Thereafter, the thickness of the exposed silicon oxide film 42 is reduced (see FIG. 2B).
That is, the silicon oxide film 42 is coated with a dilute hydrofluoric acid aqueous solution (HF: H
₂ O = 0.6% by weight: 99.4% by weight) for 3 minutes to reduce the thickness of the exposed silicon oxide film portion 42A to 10%.
nm.

[Step-150] Next, heat treatment is performed on the thinned silicon oxide film 42A. Specifically, the silicon semiconductor substrate 40 is loaded into the substrate loading / unloading section 20 of the silicon oxide film forming apparatus shown in FIG. 3 from a door (not shown) and placed on the quartz boat 24. Note that nitrogen gas is introduced from the gas introduction unit 12 into the processing chamber 10, the inside of the processing chamber 10 is set to an inert gas atmosphere such as a nitrogen gas (or may be a reduced pressure atmosphere), and The temperature of the atmosphere in the processing chamber 10 is maintained at 850 ° C. by 14. still,
In this state, the shutter 15 is kept closed. After the loading of the silicon semiconductor substrate 40 into the substrate loading / unloading unit 20 is completed, a door (not shown) is closed, nitrogen gas is introduced into the substrate loading / unloading unit 20 from the gas introduction unit 21, and the nitrogen gas is discharged from the gas exhaust unit 22. The inside of the substrate loading / unloading section 20 is set to a nitrogen gas atmosphere. Thereafter, the shutter 15 is opened, the elevator mechanism 23 is operated, the quartz boat 24 is raised, and the silicon semiconductor substrate 40 is placed in the processing chamber 10 having a double tube structure made of quartz.
Carry in. Then, a nitrogen gas containing 0.1% by volume of hydrogen chloride gas is introduced into the processing chamber 10 from the gas introduction unit 12, and 8 g of the silicon oxide film 42A is reduced.
Heat treatment is performed at 50 ° C. for 30 minutes. Thereafter, the processing room 10
The interior is set to a nitrogen gas atmosphere, the elevator mechanism 23 is operated to lower the quartz boat 24, and then the silicon semiconductor substrate 40 is unloaded from the substrate loading / unloading section 20.

[Step-160] Next, a second conductive layer 45 made of polycrystalline silicon doped with an impurity and having a thickness of 0.2 μm is formed on the entire surface by CVD (FIG. 2).
(C)), the second conductive layer 45 and the first conductive layer 4
3 is patterned. Thus, as schematically shown in FIG. 2D, the silicon oxide film 42 and the first conductive layer 4
A gate electrode for the first semiconductor element composed of the third and second conductive layers 45, and a second electrode composed of the thinned silicon oxide film 42A and the second conductive layer 45.
The gate electrode for the semiconductor element of the above can be manufactured. Note that the first semiconductor element constitutes, for example, a peripheral circuit, and the second semiconductor element constitutes, for example, a memory circuit.

[Step-170] Thereafter, in order to form an LDD structure, ions are implanted into the silicon semiconductor substrate 40, and then an insulating film is deposited on the entire surface by CVD.
A gate sidewall is formed on the side wall of the gate electrode by anisotropically etching the oxide film. After that, ion implantation is performed on the silicon semiconductor substrate 40, and then annealing is performed to activate the ion-implanted impurities. Thus, the silicon semiconductor substrate 40
Next, source / drain regions are formed. Next, an interlayer insulating layer is formed over the entire surface, connection holes and wirings are formed, so that a first semiconductor element and a second semiconductor element can be manufactured.

In Example 1, [Step-11]
0], a silicon oxide film having a thickness of 20 nm was formed on the surface of the silicon semiconductor substrate 40 by a pyrogenic oxidation method.
The silicon oxide film may be formed using water vapor containing volume% or an oxidizing gas which does not contain water vapor, such as oxygen gas or oxygen gas containing hydrochloric acid. Furthermore,
After the formation of the silicon oxide film, the atmosphere is changed to an inert gas atmosphere,
Alternatively, the temperature is raised to 850 ° C. in an inert gas atmosphere containing, for example, 0.1% by volume of hydrogen chloride gas. A preliminary heat treatment may be performed on the silicon oxide film in an inert gas atmosphere for 30 minutes. The atmospheres in these embodiments are shown in Table 2 below. In the table, “dry gas” represents an oxidizing gas atmosphere containing no oxygen gas or oxygen gas containing hydrochloric acid and does not contain water vapor, and “* wet gas” represents a wet gas atmosphere containing a halogen element. "* Inert gas" represents an inert gas atmosphere containing a halogen element.

[0045]

[Table 2] Formation of silicon oxide film Temperature rise to pre-heat treatment temperature Pre-heat treatment Wet gas None None Wet gas Inert gas * Inert gas Wet gas * Inert gas * Inert gas * Wet gas None None * Wet gas not Active gas * Inert gas * Wet gas * Inert gas * Inert gas Dry gas None None Dry gas Inactive gas * Inert gas Dry gas * Inert gas * Inert gas

Example 2 In Example 2, the formation of the silicon oxide film was performed in two stages. That is, (A) a first silicon oxide film in which a silicon oxide film is formed on the surface of a silicon layer by an oxidation method using a wet gas while maintaining an atmosphere at a temperature at which silicon atoms do not desorb from the surface of the silicon layer; A film forming step, and (B) an oxidation method using a wet gas in an atmosphere higher than the atmosphere temperature in the first silicon oxide film forming step,
Further, a silicon oxide film was formed in a second silicon oxide film forming step of forming a silicon oxide film. Step (A)
The oxidation method using the wet gas in the step (B) was defined as a pyrogenic oxidation method. Further, the method includes a temperature raising step of raising the ambient temperature from the ambient temperature in the step (A) to the ambient temperature in the step (B). By employing such a two-stage method of forming a silicon oxide film, it is possible to prevent the surface of the silicon layer from being roughened (irregularities) when the silicon oxide film is formed on the surface of the silicon layer. Further, after the formation of the silicon oxide film and before forming the first conductive layer on the silicon oxide film, a preliminary heat treatment is performed on the formed silicon oxide film. The second embodiment differs from the first embodiment only in [Step-110]. Hereinafter, only the step of forming the silicon oxide film in the second embodiment and the heat treatment (preliminary heat treatment) step immediately thereafter will be described.
The other steps may be the same as those in the first embodiment.

[Step-200] [Step-10] of Example 1
0], the silicon semiconductor substrate 40 is loaded into the substrate loading / unloading section 20 of the silicon oxide film forming apparatus shown in FIG. 3 from a door (not shown) and placed on the quartz boat 24 ((A) in FIG. 6). reference). Note that nitrogen gas is introduced from the gas introduction unit 12 into the processing chamber 10, the inside of the processing chamber 10 is set to an inert gas atmosphere such as a nitrogen gas (or may be a reduced pressure atmosphere), and The atmosphere temperature in the processing chamber 10 is maintained at 400 ° C. by 14. In this state, the shutter 15 is closed.

[Step-210] Then, the substrate loading / unloading section 2
0, the door (not shown) is closed, and the gas introduction unit 21 is inserted into the substrate carry-in / out unit 20.
, And exhausted from the gas exhaust unit 22 to make the inside of the substrate loading / unloading unit 20 a nitrogen gas atmosphere. The oxygen gas concentration in the substrate loading / unloading section 20 is monitored, and if the oxygen gas concentration becomes, for example, 20 ppm or less, it is determined that the inside of the substrate loading / unloading section 20 has a sufficient nitrogen gas atmosphere.
After that, the shutter 15 is opened (see FIG. 6B),
The quartz boat 24 is raised by operating the elevator mechanism 23, and the silicon semiconductor substrate 40 is carried into the processing chamber 10 having a double tube structure made of quartz (see FIG. 7A). Since the atmosphere temperature in the processing chamber 10 is maintained at 400 ° C. by the heater 14, it is possible to prevent the surface of the silicon semiconductor substrate 40 from being roughened.

[Step-220] Next, the atmosphere was maintained at a temperature (400 ° C. in Example 2) at which silicon atoms were not desorbed from the surface of the silicon layer (the silicon semiconductor substrate 40 in Example 2). In this state, a silicon oxide film 42 is formed on the surface of the silicon layer by an oxidation method using a wet gas. In the second embodiment, specifically, the steam generated in the combustion chamber 30 is supplied into the processing chamber 10 through the pipe 31, the gas flow path 11, and the gas introduction unit 12, and the silicon semiconductor is formed by a pyrogenic oxidation method. A silicon oxide film 42 having a thickness of 1.2 nm is formed on the surface of the substrate 40 (see FIG. 7B). The thickness of this silicon oxide film is a thickness corresponding to a few molecular layers of SiO ₂ ,
Even if the steps on the surface of the silicon semiconductor substrate are considered, the thickness is sufficient to function as a protective film. Although the residence time in the processing chamber 10 differs between the silicon semiconductor substrates located above and below the processing chamber 10, the oxidation rate at 400 ° C. is extremely low, and after the silicon oxide film is formed by the surface reaction. The increase in the thickness of the silicon oxide film is so small as to be almost negligible, and the uniformity of the thickness of the silicon oxide film can be ensured.

[Step-230] After that, the supply of the wet gas into the processing chamber 10 is stopped, and while the inert gas (nitrogen gas) is supplied from the gas introducing section 12 into the processing chamber 10, the silicon oxide film is formed. The temperature of the atmosphere in the processing chamber 10 of the film apparatus is set to, for example, 800 ° C. by the heater 14 through the soaking tube 16.
(See FIG. 8A). In addition, [Step-22]
In [Step-230], the surface of the silicon layer (silicon semiconductor substrate 40) is roughened because a silicon oxide film that also functions as a protective film is already formed on the surface of the silicon layer in [0]. Never.

[Step-240] The processing chamber 10 was heated to 800 ° C.
After the internal temperature of the inside is reached, a silicon oxide film is further formed by an oxidation method using a wet gas while maintaining the atmosphere at this temperature. Specifically, water vapor generated in the combustion chamber 30 is supplied into the processing chamber 10 through the pipe 31, the gas flow path 11, and the gas introduction unit 12, and is entirely deposited on the surface of the silicon semiconductor substrate 40 by pyrogenic oxidation. A silicon oxide film 42 having a thickness of 20 nm is formed (see FIG. 8B).

[Step-250] Thereafter, the supply of the wet gas is stopped, and the ambient temperature of the processing chamber 10 is raised to 850 ° C. by the heater 14 while the nitrogen gas is introduced into the processing chamber 10 from the gas introduction unit 12. Warm (see FIG. 9A).
Thereafter, a nitrogen gas containing 0.1% by volume of hydrogen chloride gas is introduced into the processing chamber 10 from the gas introduction unit 12, and a preliminary heat treatment is performed for 30 minutes (see FIG. 9B).

Thus, the formation of the silicon oxide film 42 on the surface of the silicon semiconductor substrate 40 is completed. Thereafter, the processing chamber 10 is set in a nitrogen gas atmosphere, the elevator mechanism 23 is operated to lower the quartz boat 24, and then the silicon semiconductor substrate 40 is carried out from the substrate carry-in / out section 20. ] Execute the subsequent steps.

Example 3 In Example 3, a silicon oxide film was formed in two steps as in Example 2. The third embodiment is different from the second embodiment in that the oxidation method using the wet gas in the steps (A) and (B) is a pyrogenic oxidation method.
The point at which 1% by volume of hydrogen chloride gas was added, and the atmosphere in the temperature raising step in which the temperature of the atmosphere was raised from the temperature in step (A) to the temperature in step (B) were changed to 0.1% hydrogen chloride gas That is, the inert gas atmosphere containing the volume% is used. Except for these points, the manufacturing method of the gate electrode of the third embodiment can be the same as that of the second embodiment. Hereinafter, only the process of forming the silicon oxide film and the heat treatment process immediately after in the third embodiment different from the second embodiment will be described.

In the third embodiment, a single-wafer silicon oxide film forming apparatus whose schematic diagram is shown in FIG. 10 was used. This silicon oxide film forming apparatus includes a processing chamber 50 and a resistance heater 51 as heating means for heating a silicon layer (for example, a silicon semiconductor substrate). The processing chamber 50 is composed of a quartz furnace tube, and accommodates a silicon semiconductor substrate, which is a material to be processed, having a silicon layer therein for forming a silicon oxide film on the silicon layer. The resistance heater 51 serving as a heating means is provided outside the processing chamber 50 and is provided substantially in parallel with the surface of the silicon layer. For example, a silicon semiconductor substrate 40, which is a material to be processed having a silicon layer, is placed on a wafer table 52, and a gate valve 53 provided at one end of the processing chamber 50 is provided.
It is carried into and out of the processing chamber 50. The silicon oxide film forming apparatus includes a gas introduction unit 54 for introducing water vapor and the like into the processing chamber 50 and a gas exhaust unit 5 for exhausting gas from the processing chamber 50.
5 is further provided. The temperature of the silicon semiconductor substrate can be measured by a thermocouple (not shown).
The hydrogen gas supplied to the combustion chamber is mixed with the oxygen gas at a high temperature in the combustion chamber and burned to generate steam. Such water vapor is supplied to the pipe and the gas introduction unit 5.
4 and supplied into the processing chamber 50. In addition, illustration of a combustion chamber and piping was omitted.

Alternatively, a single-wafer silicon oxide film forming apparatus of the type schematically shown in FIG. 11 can be used.
In the single-wafer silicon oxide film forming apparatus shown in FIG. 11, the heating means is composed of a plurality of lamps 51A that emit infrared light or visible light. The temperature of the silicon semiconductor substrate is measured by a pyrometer (not shown). Other structures can be basically the same as those of the silicon oxide film forming apparatus shown in FIG. 10, and thus detailed description is omitted.

[Step-300] First, after a device isolation region and the like are formed in the silicon semiconductor substrate in the same manner as in the first embodiment, fine particles and metal impurities on the surface of the silicon semiconductor substrate are removed by RCA cleaning. Next, the surface of the silicon semiconductor substrate is washed with a 0.1% aqueous hydrofluoric acid solution to expose the surface of the silicon semiconductor substrate.

[Step-310] Next, the silicon semiconductor substrate 40 mounted on the wafer stage 52 is connected to the gate valve 5 of the silicon oxide film forming apparatus shown in FIG. 10 or FIG.
3, the gate valve 53 is closed, and the gate valve 53 is closed. At this time, the atmosphere in the processing chamber 50 is set to an inert gas atmosphere heated to about 400 ° C. by a heating unit. By setting the atmosphere in the processing chamber 50 under such conditions, the silicon semiconductor substrate 40
It is possible to suppress the occurrence of roughness on the surface.

[Step-320] Then, the atmosphere was maintained at a temperature (400 ° C. in Example 3) at which silicon atoms were not desorbed from the surface of the silicon layer (the silicon semiconductor substrate 40 in Example 3). In this state, for example, a silicon oxide film 42 is formed on the surface of the silicon layer by an oxidation method using a wet gas containing 0.1% by volume of hydrogen chloride gas. In the third embodiment, specifically, steam generated in a combustion chamber (not shown) is supplied into a processing chamber 50 through a pipe (not shown) and a gas introduction unit 54, and the pyrogenic oxidation method is used. Thus, a silicon oxide film having a thickness of 1.2 nm is formed on the surface of the silicon semiconductor substrate 40.

[Step-330] Then, while supplying a wet gas containing, for example, 0.1% by volume of hydrogen chloride gas into the processing chamber 50, the atmosphere temperature in the processing chamber 50 is set to 800 ° C. by a heating means. Heat up to Example 3
In the above, since the heating means is disposed substantially in parallel with the surface of the silicon layer, it is possible to suppress the occurrence of in-plane temperature variation of the silicon layer (silicon semiconductor substrate) when the temperature of the silicon layer is increased. It is possible to effectively suppress the in-plane thickness variation of the silicon oxide film formed during the temperature rise.

[Step-340] Processing chamber 50 at 800 ° C.
After the internal temperature of the inside is reached, a silicon oxide film is further formed by an oxidation method using, for example, a wet gas containing 0.1% by volume of hydrogen chloride gas while maintaining the atmosphere at this temperature. Specifically, water vapor and hydrogen chloride gas generated in the combustion chamber are supplied into the processing chamber 50 through a pipe and a gas introduction unit 54, and a silicon semiconductor substrate 40 having a total thickness of 20 nm is formed on the surface of the silicon semiconductor substrate 40 by a pyrogenic oxidation method. An oxide film 42 is formed.

[Step-350] Thereafter, the supply of the wet gas is stopped, and for example, a nitrogen gas containing 0.1% by volume of hydrogen chloride gas is introduced into the processing chamber 50 from the gas introducing section 54 while the processing chamber 50 is being supplied. Temperature of 850 by heating means
Heat to ゜ C. Thereafter, while the atmosphere temperature of the processing chamber 50 is maintained at 850 ° C. by a heating means, a nitrogen gas containing 0.1% by volume of hydrogen chloride gas is introduced into the gas introduction unit 5.
4 and introduced into the processing chamber 50 and heat-treated for 5 minutes.

[Step-360] Through the above, the formation of the silicon oxide film on the surface of the silicon semiconductor substrate 40 is completed. Thereafter, the inside of the processing chamber 50 is set to a nitrogen gas atmosphere, the gate valve 53 is opened, and the silicon semiconductor substrate 40 placed on the wafer table 52 is carried out of the processing chamber 50. Then, the steps after [Step-120] of the first embodiment are executed.

Although the present invention has been described based on the preferred embodiments, the present invention is not limited to these embodiments. The various conditions and the structure of the silicon oxide film forming apparatus described in the embodiments are merely examples, and can be changed as appropriate. The formation of the silicon oxide film is not only a pyrogenic oxidation method, but also an oxidation method using water vapor generated by heating pure water, an oxidation method using water vapor generated by bubbling heated pure water with an oxygen gas or an inert gas, Alternatively, a method combining these oxidation methods can be used, or an oxidizing gas that does not contain water vapor such as oxygen gas or oxygen gas containing hydrochloric acid can be used.

[Step-220] and [Step-24]
0] or the oxidation methods in [Step-320] and [Step-340] may be the same oxidation method or different oxidation methods. In the embodiments, the silicon oxide film is formed exclusively on the surface of the silicon semiconductor substrate. However, the silicon oxide film may be formed on the surface of an epitaxial silicon layer, a polycrystalline silicon layer, or an amorphous silicon layer. Alternatively, a silicon oxide film may be formed on the surface of a silicon layer in the SOI structure, or a silicon element may be formed on a substrate on which a semiconductor element or a component of the semiconductor element is formed, or on a surface of a silicon layer formed thereon. An oxide film may be formed. Furthermore, a silicon oxide film may be formed on a surface of a silicon element formed on a substrate on which a semiconductor element or a component of the semiconductor element is formed, or a base insulating layer formed on the substrate. For example, CVD
Table 3 shows conditions for forming a single-crystal epitaxial silicon layer selectively on the surface of a silicon semiconductor substrate by the epitaxial growth method based on the method.

[0066]

Table 3 Gas used: H ₂ : 50 slm SiH ₂ Cl ₂ : 100 sccm B ₂ H ₆ / H ₂ : 0.1% -100 sccm HCl: 50 sccm Temperature: 750 ° C. Pressure: 5.3 × 10 ³ Pa (40 Torr) Thickness: 30 nm

Alternatively, in Example 1, [Step-10
0], the surface of the silicon semiconductor substrate 40 was cleaned with a 0.1% aqueous solution of hydrofluoric acid, and then [Step-11].
0], the silicon semiconductor substrate 40 was carried into the silicon oxide film forming apparatus, but the atmosphere from cleaning the surface of the silicon semiconductor substrate 40 to carrying it into the silicon oxide film forming apparatus was changed to an inert gas (eg, nitrogen gas) atmosphere. It may be. Incidentally, such an atmosphere is, for example, an atmosphere of a surface cleaning apparatus for a silicon semiconductor substrate is an inert gas atmosphere,
In addition, a method in which the silicon semiconductor substrate 40 is placed in a transport box filled with an inert gas and is loaded into the substrate loading / unloading section 20 or the processing chamber 50 of the silicon oxide film forming apparatus,
As shown in a schematic diagram in FIG. 2, a silicon oxide film is formed from the silicon semiconductor substrate surface cleaning device using a surface cleaning device, a silicon oxide film forming device, a transport tool, a cluster tool device including a loader and an unloader. The transfer path connects the substrate loading / unloading section 20 of the apparatus to the processing chamber 50,
This can be achieved by such a surface cleaning apparatus and a method of setting the atmosphere of the transport path to an inert gas atmosphere.

Alternatively, instead of cleaning the surface of the silicon semiconductor substrate 40 with an aqueous 0.1% hydrofluoric acid solution, a gas phase cleaning method using anhydrous hydrogen fluoride gas is performed under the conditions shown in Table 4. The surface of the silicon semiconductor substrate 40 may be cleaned. Note that methanol is added to prevent generation of particles. Alternatively, the surface of the silicon semiconductor substrate 40 may be cleaned by a vapor phase cleaning method using hydrogen chloride gas under the conditions exemplified in Table 5.
Before the surface cleaning of the silicon semiconductor substrate 40 is started or after the surface cleaning is completed, the atmosphere in the surface cleaning apparatus or the atmosphere in the transfer path may be an inert gas atmosphere,
For example, a vacuum atmosphere of about 1.3 × 10 ⁻¹ Pa (10 ⁻³ Torr) may be used. When the atmosphere in the transfer path or the like is a vacuum atmosphere, the atmosphere in the substrate loading / unloading section 20 or the processing chamber 50 of the silicon oxide film forming apparatus when loading the silicon semiconductor substrate is set to, for example, 1.3 × 10 3. ^-1 Pa (10 ^-3
(Torr), and after the loading of the silicon semiconductor substrate is completed, the substrate loading / unloading section 20 or the processing chamber 50 is set.
May be an inert gas (for example, nitrogen gas) atmosphere at atmospheric pressure.

[0069]

[Table 4] Anhydrous hydrogen fluoride gas: 300 sccm Methanol vapor: 80 sccm Nitrogen gas: 1000 sccm Pressure: 0.3 Pa Temperature: 60 ° C

[0070]

[Table 5] Hydrogen chloride gas / nitrogen gas: 1% by volume Temperature: 800 ° C

As the silicon oxide film forming apparatus in these cases, the silicon oxide film forming apparatus shown in FIGS. 3, 10, and 11 or FIGS. 13 and 14 described later can be used. As a result, the surface of the silicon layer terminated with hydrogen or fluorine can be kept clean before the formation of the silicon oxide film. As a result, moisture, organic substances, or Si-OH is taken into the formed silicon oxide film. As a result, it is possible to effectively prevent the characteristics of the formed silicon oxide film from deteriorating or generating defects.

FIG. 13 is a schematic cross-sectional view of a vertical silicon oxide film forming apparatus slightly different from the vertical silicon oxide film forming apparatus shown in FIG. The processing chamber 10 of the vertical silicon oxide film forming apparatus includes an upper region 10A and a lower region 10B, and the ambient temperature of the lower region 10B is controlled by a heater 14. On the other hand, the upper region 10
Outside of A, a plurality of lamps 14A that emit infrared light or visible light are provided. Then, for example, in the same step as [Step-220] of Example 2, the surface of the silicon layer is oxidized using a wet gas while maintaining an atmosphere at a temperature at which silicon atoms are not desorbed from the surface of the silicon layer. A silicon oxide film is formed in the lower region 10 </ b> B of the processing chamber 10. At this time, the ambient temperature of the upper region 10A of the processing chamber 10 is maintained at 400 ° C. by the lamp 14A. Thereafter, in the same step as [Step-230] of the second embodiment, the supply of the wet gas into the processing chamber 10 is stopped, and an inert gas (for example, nitrogen gas) is supplied from the gas introduction unit 12 to the processing chamber 1.
0, the ambient temperature of the upper region 10A of the processing chamber 10 of the silicon oxide film forming apparatus is raised to a desired temperature by the lamp 14A, and then the quartz boat 24 is raised by operating the elevator mechanism 23. Then, the silicon semiconductor substrate 40 is moved to the upper region 10A of the processing chamber 10.
Then, in a step similar to [Step-240] of the second embodiment, a silicon oxide film 42 is formed on the surface of the silicon semiconductor substrate 40 by a pyrogenic oxidation method. Next, in the same step as [Step-250] of the second embodiment, the supply of the wet gas is stopped, and an inert gas (for example, nitrogen gas) is introduced into the processing chamber 10 from the gas introduction unit 12 while the processing chamber is stopped. The temperature of the atmosphere in the upper region 10A of 10 is raised to 850 ° C. by the lamp 14A. Thereafter, an inert gas (for example, nitrogen gas) containing 0.1% by volume of hydrogen chloride gas is introduced into the processing chamber 10 from the gas introduction unit 12,
In the upper region 10A of the processing chamber 10, heat treatment is performed for 30 minutes.

FIG. 14 is a schematic cross-sectional view of a single-wafer silicon oxide film forming apparatus having a slightly different form from the single-wafer silicon oxide film forming apparatus shown in FIG. The processing chamber 50 of the single-wafer silicon oxide film forming apparatus includes a first region 50A and a second region 50B, and the ambient temperature of each of the first region 50A and the second region 50B is a lamp 151A. And the lamp 151B. Then, for example, in the same step as [Step-320] of the third embodiment, while maintaining the atmosphere at a temperature at which silicon atoms do not desorb from the surface of the silicon layer, the oxidation of the silicon layer is performed using a wet gas. A silicon oxide film is formed on the surface, and this silicon oxide film is formed in the first region 50A of the processing chamber 50. The first area 50
The control of the ambient temperature in A is performed by the lamp 151A. At this time, the ambient temperature in the second region 50B of the processing chamber 50 is maintained at 400 ° C. by the lamp 151B. Then, in the same step as [Step-330] of the third embodiment, while the supply of the wet gas into the processing chamber 50 is continued, the ambient temperature of the second region 50B of the processing chamber 50 is set to a desired value by the lamp 151B. Then, the silicon semiconductor substrate is moved to the second region 50B. afterwards,
In the same step as [Step-340], the ambient temperature of the second region 50B of the processing chamber 50 is set to the desired temperature by using the lamp 1.
While holding the silicon oxide film 51B, a silicon oxide film is further formed by an oxidation method using a wet gas. afterwards,
In the same step as [Step-350], the supply of the wet gas is stopped, and an inert gas (for example, nitrogen gas) is introduced into the processing chamber 50 from the gas introduction unit 54, and the second region of the processing chamber 50 is The ambient temperature of 50B is raised to 850 ° C. by the lamp 151B. After that, hydrogen chloride gas was added to 0.1 g.
An inert gas (for example, nitrogen gas) containing 1% by volume is introduced into the processing chamber 50 from the gas introduction unit 54, and heat treatment is performed for 5 minutes. In addition, instead of the lamp in the silicon oxide film forming apparatus of FIG. 14, a resistance heater can be used as shown in FIG.

Table 6 shows that a silicon oxide film was formed on the surface of the silicon layer by an oxidation method using a wet gas while maintaining the atmosphere at a temperature at which silicon atoms were not desorbed from the surface of the silicon layer. Atmosphere in a silicon oxide film forming step (indicated as a first step in Table 6), an atmosphere in a step of raising the ambient temperature to a desired temperature (in Table 6, referred to as a first temperature increase), a desired temperature With the atmosphere maintained, by the oxidation method using a wet gas,
Further, an atmosphere in a second silicon oxide film forming step of forming a silicon oxide film (indicated as a second step in Table 6), and a step of raising the temperature of the atmosphere in order to perform a heat treatment on the formed silicon oxide film The combinations of the atmospheres (in Table 6, described as the second temperature increase) are shown. Table 6
Medium and wet gas atmospheres are described as "wet gas", wet gas atmospheres containing halogen elements are described as "* wet gas", and inert gas atmospheres are described as "inert gas" and contain halogen elements Inert gas atmosphere "* inert gas"
It was written. In Table 6, "none / inert gas / * inert gas" does not require pre-heat treatment, and when pre-heat treatment is performed, the atmosphere is heated to heat-treat the formed silicon oxide film. In this case, the atmosphere in the step (b) may be an inert gas atmosphere or an inert gas atmosphere containing a halogen element. Here, the combinations of various atmospheres shown in Table 6 correspond to the silicon oxide film forming apparatuses shown in FIGS.
This can be realized by the silicon oxide film forming apparatus shown in FIG. 1 or FIG. 14, or a combination thereof, and furthermore, the cluster tool apparatus shown in FIG.

[0075]

[Table 6] 1st process 1st temperature rise 2nd process 2nd temperature rise Dry gas Inert gas Dry gas None / Inert gas / * Inert gas Same as above Same as above Wet gas Same as above Same as above * Wet gas Same as above Same as above * Inert gas No dry gas / Inert gas / * Inert gas Same as above Same as above Wet gas Same as above Same as above * Wet gas Same as above Same as above Wet gas Dry gas None / Inert gas / * Inert gas Same as above Same as above Wet gas Same as above Same as above * Wet gas Same as above * Wet gas Dry gas None / Inert gas / Same as above Inert gas Same as above Same as above Wet gas Same as above Same as above * Wet gas Same as above Wet gas Inert gas No dry gas / Inert gas / * Same as above * Inert gas Dry gas None / Inert gas / * Inert gas Same as above Wet gas Same as above Same as above * Wet gas Same as above Same as above Wet gas Dry gas None / Inert gas / * Inert gas Same as above Same as above Wet gas Same as above Same as above * Wet gas Same as above Same as above * Wet gas Dry gas None / Inert gas / * Inert gas Same as above Same as above Wet gas Same as above * Wet gas Same as above * Dry gas Inert gas Dry gas None / Inert gas Same as above Wet gas Same as above Same as above * Wet gas Same as above * Inert gas No dry gas / Inert gas / * Inert gas Same as above Wet gas Same as above Same as above * Wet gas Same as above Same as above Wet gas Dry gas None / Inert gas Same as above Same as above Wet gas Same as above Same as above * Wet gas Same above Same as above * Wet gas Dry gas None / Inert gas / * Inert gas Same as above Wet gas Same as above Same as above * Wet gas Same as above

In the embodiment, two types of silicon oxide films are formed, but the thickness of the silicon oxide film in the present invention is not limited to two types. For example, as shown in FIGS. 15 and 16, three types (or more) of silicon oxide films can be formed. In this case, for example, in [Step-120] of the first embodiment, the first film having a thickness of, for example, 0.05 μm is formed on the silicon oxide film 42.
After the formation of the conductive layer 43, in [Step-130], the first conductive layer 43 is selectively removed to expose a part of the silicon oxide film 42 (see FIG. 15A). Next, the thickness of the exposed silicon oxide film 42 is reduced (see FIG. 15B). After that, a part of the resist 44 is removed, and the first conductive layer 43 is selectively etched again using the remaining resist 44 as an etching mask (FIG. 16A. Then, the exposed silicon oxide film 4).
The thickness of 2, 42A is reduced (see FIG. 16B).
In this manner, an element formation region having the thinnest silicon oxide film 42A, the intermediately thin silicon oxide film 42B, and the thickest silicon oxide film 42 can be formed.

[0077]

According to the method of manufacturing a gate electrode in a semiconductor device of the present invention, the formation of a silicon oxide film only needs to be performed essentially once, as in the conventional method of forming two types of silicon oxide films. A step of selectively removing an unnecessary silicon oxide film and forming a silicon oxide film again, a step of selectively removing the silicon oxide film, and the like are unnecessary. Therefore,
A gate electrode having a silicon oxide film having a different thickness can be manufactured without increasing the number of manufacturing steps to the left. Further, since it is not necessary to form a resist directly on the silicon oxide film, it is possible to prevent deterioration in reliability and characteristics of the silicon oxide film. Furthermore, since the thickness of the exposed silicon oxide film is reduced and then the thinned silicon oxide film is subjected to a heat treatment, the contamination caused by the thinning of the silicon oxide film and the removal and repair of defects are performed. As a result, a silicon oxide film having excellent characteristics can be obtained.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic partial cross-sectional views illustrating a method for manufacturing a gate electrode in a semiconductor device of Example 1 with a semiconductor substrate. FIGS.

FIG. 2 is a schematic partial cross-sectional view of a semiconductor substrate for illustrating a method for manufacturing a gate electrode in the semiconductor device of Example 1, following FIG. 1;

FIG. 3 is a schematic view of a vertical batch type silicon oxide film forming apparatus used in Example 1.

FIG. 4 is a schematic sectional view of a silicon oxide film forming apparatus and the like for explaining a method of forming a silicon oxide film in Example 1.

FIG. 5 is a schematic cross-sectional view of a silicon oxide film forming apparatus and the like for explaining a method of forming a silicon oxide film in Example 1, following FIG. 4;

FIG. 6 is a schematic sectional view of a silicon oxide film forming apparatus and the like for explaining a method of forming a silicon oxide film in Example 2.

FIG. 7 is a schematic cross-sectional view of a silicon oxide film forming apparatus and the like for explaining a method of forming a silicon oxide film in Example 2 following FIG. 6;

FIG. 8 is a schematic cross-sectional view of a silicon oxide film forming apparatus and the like for describing a method of forming a silicon oxide film in Example 2, following FIG. 7;

FIG. 9 is a schematic cross-sectional view of a silicon oxide film forming apparatus and the like for explaining a method of forming a silicon oxide film in Example 2, following FIG.

FIG. 10 is a schematic view of a single-wafer silicon oxide film forming apparatus used in Example 3.

FIG. 11 is a schematic cross-sectional view of a single-wafer silicon oxide film forming apparatus having a slightly different structure from FIG.

FIG. 12 is a schematic view of a cluster tool device.

13 is a schematic cross-sectional view of a vertical silicon oxide film forming apparatus having a slightly different type from the vertical silicon oxide film forming apparatus shown in FIG. 3;

FIG. 14 is a schematic cross-sectional view of a single-wafer silicon oxide film forming apparatus having a slightly different type from the single-wafer silicon oxide film forming apparatus shown in FIG. 11;

FIG. 15 is a schematic partial cross-sectional view of a silicon semiconductor substrate or the like for describing a method of forming silicon oxide films having three different thicknesses.

FIG. 16 is a schematic partial cross-sectional view of a silicon semiconductor substrate and the like for explaining a method of forming three types of silicon oxide films, following FIG.

FIG. 17 is a schematic partial cross-sectional view of a silicon semiconductor substrate and the like for describing a conventional method of forming silicon oxide films having two different thicknesses.

FIG. 18 is a schematic partial cross-sectional view of a silicon semiconductor substrate or the like for explaining a conventional method for forming silicon oxide films having two different thicknesses, following FIG. 17;

FIG. 19 is a schematic partial cross-sectional view of a silicon semiconductor substrate and the like for explaining a conventional method of forming silicon oxide films having two different thicknesses.

FIG. 20 is a schematic partial cross-sectional view of a silicon semiconductor substrate or the like for explaining a conventional method for forming silicon oxide films having two different thicknesses, following FIG. 19;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Processing chamber, 11 ... Gas flow path, 12 ... Gas introduction part, 13 ... Gas exhaust part, 14 ... Heater,
15 ... shutter, 16 ... heat equalizing tube, 20 ...
Substrate loading / unloading section, 21 gas introduction section, 22 gas exhaust section, 23 elevator mechanism, 24 quartz boat, 30 combustion chamber, 31 pipe, 40・ ・
Silicon semiconductor substrate, 41 ... element isolation region, 42
..Silicon oxide films, 42A, 42B... Thinned silicon oxide films, 43... First conductive layer, 44.
.Resist, 45... Second conductive layer

Claims (24)

[Claims] 1. A semiconductor device comprising: a first semiconductor element; and a second electrode having a gate electrode formed of a silicon oxide film having a thickness different from a thickness of a silicon oxide film forming a gate electrode of the first semiconductor element. A method for manufacturing each gate electrode in a semiconductor device comprising: (a) a step of forming a silicon oxide film on a surface of a silicon layer; and (b) a first conductive layer on the silicon oxide film. (C) selectively removing the first conductive layer to expose a portion of the silicon oxide film; and (d) reducing the thickness of the exposed silicon oxide film. (E) a step of performing a heat treatment on the thinned silicon oxide film; and (f) a step of patterning the second conductive layer and the first conductive layer after forming a second conductive layer on the entire surface. , Consisting of
Thus, a gate electrode for a first semiconductor device composed of a silicon oxide film, a first conductive layer and a second conductive layer,
A method for manufacturing a gate electrode in a semiconductor device, comprising: manufacturing a gate electrode for a second semiconductor element including a thinned silicon oxide film and a second conductive layer. 2. The method for manufacturing a gate electrode in a semiconductor device according to claim 1, wherein the heat treatment in the step (e) is performed in an inert gas atmosphere containing a halogen element. 3. The method for manufacturing a gate electrode in a semiconductor device according to claim 2, wherein the halogen element is chlorine. 4. The semiconductor device according to claim 3, wherein the chlorine is in the form of hydrogen chloride, and the concentration of hydrogen chloride contained in the inert gas is 0.02 to 10% by volume. Method for manufacturing gate electrode. 5. The method for manufacturing a gate electrode in a semiconductor device according to claim 2, wherein the heat treatment is performed at a temperature of 700 to 950 ° C. 6. The method according to claim 5, wherein the heat treatment is a furnace annealing process. 7. A method according to claim 1, wherein after forming a silicon oxide film on the surface of the silicon layer in the step (a), before forming the first conductive layer on the silicon oxide film, the formed silicon oxide film is removed. The method for manufacturing a gate electrode in a semiconductor device according to claim 1, wherein heat treatment is performed. 8. The method for manufacturing a gate electrode in a semiconductor device according to claim 7, wherein the heat treatment is performed in an inert gas atmosphere containing a halogen element. 9. The method for manufacturing a gate electrode in a semiconductor device according to claim 8, wherein the halogen element is chlorine. 10. The semiconductor device according to claim 9, wherein chlorine is in the form of hydrogen chloride, and the concentration of hydrogen chloride contained in the inert gas is 0.02 to 10% by volume. Method for manufacturing gate electrode. 11. The method for manufacturing a gate electrode in a semiconductor device according to claim 7, wherein the heat treatment is performed at a temperature of 700 to 950 ° C. 12. A method for forming a silicon oxide film on the surface of a silicon layer in the step (a) comprises: (A) using a wet gas while maintaining an atmosphere at a temperature at which silicon atoms are not desorbed from the surface of the silicon layer. A first silicon oxide film forming step of forming a silicon oxide film on the surface of the silicon layer by the oxidizing method, and (B) a wet gas in an atmosphere higher than the ambient temperature in the first silicon oxide film forming step. 2. The method for manufacturing a gate electrode in a semiconductor device according to claim 1, further comprising a second silicon oxide film forming step of forming a silicon oxide film by an oxidation method using a silicon oxide film. 13. A temperature according to claim 12, wherein the temperature at which silicon atoms do not desorb from the surface of the silicon layer is a temperature at which the bond between the atoms terminating the silicon layer surface and the silicon atoms is not broken. A method for manufacturing a gate electrode in a semiconductor device according to the present invention. 14. The semiconductor according to claim 13, wherein the temperature at which silicon atoms do not desorb from the surface of the silicon layer is a temperature at which a Si—H bond is not broken or a temperature at which a Si—F bond is not broken. Method for manufacturing a gate electrode in an apparatus. 15. The oxidation method using a wet gas in the step (A) and / or the step (B) includes a pyrogenic oxidation method, an oxidation method using steam generated by heating pure water, and an oxygen gas or an inert gas. 2. The method according to claim 1, wherein at least one oxidation method is selected from oxidation methods using steam generated by bubbling heated pure water with a gas.
3. A method for manufacturing a gate electrode in the semiconductor device according to 2. 16. The method according to claim 15, wherein the wet gas in the step (A) and / or the step (B) contains a halogen element. 17. The method for manufacturing a gate electrode in a semiconductor device according to claim 16, wherein the halogen element is chlorine. 18. The gate according to claim 17, wherein chlorine is in the form of hydrogen chloride, and the concentration of hydrogen chloride contained in the wet gas is 0.02 to 10% by volume. How to make electrodes. 19. A temperature raising step of raising the ambient temperature from the ambient temperature in the step (A) to the ambient temperature in the step (B), wherein the atmosphere in the temperature raising step is an oxidation containing an inert gas atmosphere or a wet gas. The method for manufacturing a gate electrode in a semiconductor device according to claim 12, wherein the atmosphere is an atmosphere. 20. The method according to claim 19, wherein the inert gas atmosphere or the oxidizing atmosphere containing a wet gas contains a halogen element. 21. The method according to claim 20, wherein the halogen element is chlorine. 22. The method according to claim 21, wherein the chlorine is in the form of hydrogen chloride, and the concentration of hydrogen chloride contained in the inert gas atmosphere or the wet gas is 0.02 to 10% by volume. A method for manufacturing a gate electrode in a semiconductor device according to the present invention. 23. An atmosphere maintained at a temperature at which silicon atoms are not desorbed from the surface of a silicon layer before forming a silicon oxide film in the step (A) is an inert gas atmosphere. A method for manufacturing a gate electrode in the semiconductor device according to claim 12. 24. The method according to claim 14, further comprising a step of cleaning the surface of the silicon layer before the step (a), wherein the step (a) is started without exposing the silicon layer after the surface cleaning to the atmosphere. 2. A method for manufacturing a gate electrode in the semiconductor device according to 1.