JP2798321B2 - 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, and more particularly to a method for forming a contact.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional method of manufacturing a semiconductor device, in which a contact is made directly with an active region silicided with titanium on a silicon substrate, and wiring is performed with a polycrystalline silicon film. As shown in FIG. 4A, a P-type silicon substrate or a so-called LOCOS method (Local Oxidation of S) is formed in a P well region 1 formed in the silicon substrate.
A thick silicon oxide film 2 having a thickness of, for example, 600 nm is formed in a water vapor atmosphere at 1000 ° C. to separate the active regions. Simultaneously thick silicon oxide film 2
Under this, a P-type channel cut layer 3 is formed in a self-aligned manner by boron ion-implanted before oxidation.

Then, arsenic ions are applied to the active region separated by the thick silicon oxide film 2, for example, at 50 keV.
After implanting an amount of 3 × 10 ¹⁵ cm ⁻² at an energy of 950 ° C. for 30 minutes in an oxygen atmosphere, the crystallinity of the P-well region 1 is restored and arsenic ions are activated. , By diffusion of arsenic ions
A type impurity active layer 4 is formed.

Next, as shown in FIG. 4B, a titanium film 5 having a thickness of, for example, 100 nm is formed by depositing titanium on the entire surface of the substrate by sputtering.

After that, for example, at 700 ° C. in a nitrogen atmosphere,
When a heat treatment is performed by a lamp annealing method for 0 second, the titanium film 5 reacts with the n-type impurity active layer 4 where the silicon substrate surface is exposed, and a titanium silicide film 6 is formed on the surface in a self-aligned manner. On the other hand, the titanium film 5 does not react on the thick silicon oxide film 2. Next, the unreacted titanium film 5 on the thick silicon oxide film 2 is removed by, for example, a mixed solution of sulfuric acid and a hydrogen peroxide solution, to thereby obtain FIG.
As shown in (c), only about 150 n is formed on the n-type impurity active layer 4.
m of titanium silicide film 6 is formed.

Next, as shown in FIG. 4D, a silicon oxide film 7 having a thickness of, for example, 200 nm is formed as an interlayer insulating film by, for example, a chemical vapor deposition method under reduced pressure, a so-called reduced pressure CVD method. Next, the resist is patterned by a known photolithography method, and then a desired portion is directly formed by etching a desired portion by a dry etching method using a Freon-based gas, for example, methane trifluoride (CHF3). . Reference numeral 6a denotes an oxide formed by exposing the titanium silicide film 6 to air after the dry etching.

Next, as shown in FIG. 4E, after performing a pretreatment with sulfuric acid or the like, a polycrystalline silicon film into which phosphorus is introduced as an n-type impurity, that is, a so-called phosphorus-doped polycrystalline silicon film is formed by a low pressure CVD method. For example, after depositing 100 nm,
A phosphorus-doped polycrystalline silicon film 9 is formed only at a desired portion by a photolithography method and a dry etching method using a Freon-based gas, for example, carbon tetrafluoride (CF4), to form a wiring layer.

At this time, the surface of the titanium silicide film 6 in the direct contact 8 has an oxidized portion 6a, so that ohmic characteristics cannot be obtained. Therefore, after the wiring layer is formed by the phosphorus-doped polycrystalline silicon film 9, silicon ions or arsenic ions are implanted at a high implantation amount of, for example, 1 × 10 ¹⁶ cm ⁻² or more, and the surface 6a of the titanium silicide film 6 where the surface is oxidized is Was obtained and the ohmic characteristics were obtained by mixing the interface between the phosphorus-doped polycrystalline silicon film 9 and the titanium silicide film 6 [Ref. -SB-20 "Poly-Si direct contact characteristics on TiSi2 film" (Mukai et al.) ". For example, when the thickness of the phosphorus-doped polycrystalline silicon film 9 is 100 nm, the implantation energy is 180 keV and the implantation amount is set so that the projected range of arsenic ions reaches the interface between the phosphorus-doped polycrystalline silicon film 9 and the n-type impurity active layer 4. The injection was performed at 2 × 10 ¹⁶ cm ⁻² . At this time, the phosphorus-doped polycrystalline silicon film 9 and the silicon oxide film 7 are formed so that the accelerated arsenic ions do not pass through the silicon oxide film 7 as an interlayer insulating film and reach the n-type impurity diffusion layer 4 and other impurity diffusion layers. It is necessary to optimize the thickness of the film, the ion implantation energy for mixing, and the amount of ion implantation. The ion implantation for mixing may be performed after the formation of the phosphorus-doped polysilicon film 9.

As another method for manufacturing a semiconductor device, as shown in FIG. 5A, a silicide layer is used as a first wiring layer, a contact is provided thereon via an insulating layer, and a second wiring layer is formed. When arranging layers, after forming a first silicon oxide film 10 as a first interlayer insulating film on the silicon substrate 1,
For example, after depositing a polycrystalline silicon film 11 having a thickness of 200 nm into which an n-type impurity is introduced by a low-pressure CVD method, only a desired portion is left as a wiring layer by a photolithography method and a dry etching method. In the same manner as described above, a titanium silicide film 12 is formed only on the polycrystalline silicon film 11 by a silicide reaction to form a first wiring layer.

Next, as shown in FIG. 5 (b), a second silicon oxide film 13 is formed as a second interlayer insulating film by a low pressure CVD method, for example, to a thickness of 200 nm, and then a first polycrystalline silicon film is formed. After a contact 14 is formed directly on the substrate 11, a second polycrystalline silicon film 15 serving as a second wiring layer is formed, and arsenic ions or silicon ions are implanted at a high energy and in a high implantation amount. By mixing the interface between the crystalline silicon film 15 and the titanium silicide film 12, ohmic characteristics have been obtained.

Further, as another method of manufacturing a semiconductor device, as shown in FIG. 6A, when a metal interconnection is formed by making contact on a silicided active region or on a polycrystalline silicon film, as shown in FIG. In the same manner as in the conventional example, a thick silicon oxide film 2, a P-type channel cut layer 3, an n-type impurity diffusion layer 4, a titanium silicide film 6, a silicon oxide film 7 Is formed, a desired portion of the photoresist film is removed by photolithography, and then, for example, about の of the silicon oxide film 7 is isotropically etched with a diluted hydrofluoric acid solution. Thereafter, the remaining film thickness is vertically etched by a dry etching method using a Freon-based gas, for example, methane trifluoride (CHF3) to form a tapered core. To form a tact 16. In this state, if left in the air for a short time, the surface of the titanium silicide film 6 exposed at the bottom of the contact 16 is oxidized and the oxide
a is created. This oxide 6a inhibits ohmic contact.

Next, as shown in FIG. 6B, 1 × 10 ⁻⁵ Pa
Using argon ions in a vacuum at the following pressure,
After performing a sputter etching of, for example, 10 nm corresponding to a silicon oxide film, an aluminum alloy film, for example, a film containing 0.5% by weight of silicon in aluminum is deposited by a sputtering method in a continuous process in the same vacuum atmosphere. At this time, on the surface of the titanium silicide layer 6, the oxide 6a formed by exposure to air at the time of forming the contact remains.

Next, as shown in FIG. 6C, a photolithography method and a chlorine-based gas such as carbon tetrachloride (CC
An aluminum wiring layer 17 is formed only on a desired portion by dry etching using l4).

In this conventional example, the aluminum alloy film 17 was directly wired to the contact 16, but in order to prevent silicon in the aluminum alloy from being deposited in the contact 16, a titanium nitride (TiN) film and a titanium tungsten (T
There is also an example in which an aluminum alloy film is formed after forming a so-called barrier metal film such as an iW) film or a molybdenum silicide (MoSi2) film. Although the case where a contact is formed on the silicide film has been described, a method of similarly forming a contact on the polycrystalline silicon film and forming an aluminum wiring by using a barrier metal is also available.

[0015]

Since a conventional semiconductor device is manufactured as described above, it is difficult to form a contact directly using a polysilicon film on a titanium silicide film as an active region or a wiring layer. It is necessary to implant an arsenic or silicon ion at a high energy and a high implantation amount to mix the interface between the silicide film and the polysilicon film serving as the wiring layer. Is required.

In addition, during ion implantation for mixing,
The implanted ions permeate the polycrystalline silicon film, which is the wiring layer, and mix the interface with the silicide film, but do not enter the other regions such as the active region formed on the silicon substrate through the interlayer insulating film. Since there is a condition that the thickness of the interlayer insulating film and the wiring layer is not restricted, the thickness of the interlayer insulating film and the wiring layer is restricted, and thus the structure of the semiconductor device is restricted.

Further, in the method by ion implantation, as shown in the above-mentioned reference, mixing at the interface between the polycrystalline silicon film as the wiring layer and the titanium silicide film is not sufficiently performed, and there is a defect. There is a problem that it is difficult to form a direct contact having characteristics. Similarly, when a contact is formed on a titanium silicide film and a metal wiring is arranged, the manufacturing method is complicated, and the oxidized and insulating portion of the surface of the titanium silicide film is completely removed by the method described above. Since it is difficult to remove, it has been difficult to obtain a contact having stable ohmic characteristics with good reproducibility.

In addition to the method of obtaining ohmic characteristics by ion implantation, there is also a method of removing the oxide 6a on the titanium silicide film 6 with a hydrofluoric acid solution. In this method, titanium dissolves in the solution, and the solution and the subsequent processing are performed. However, there is a problem in that the resulting semiconductor device is contaminated, and in some cases, the silicide film is dissolved by hydrofluoric acid.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a simple manufacturing method, small structural restrictions on a semiconductor device, and a stable ohmic characteristic with good reproducibility. It is an object of the present invention to provide a method of manufacturing a semiconductor device which can be performed.

[0020]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device , comprising the steps of:
After forming silicide film by Idid reaction, interlayer insulating film
A contact hole is formed at a predetermined position of the interlayer insulating film.
Forming a wiring layer and then forming a wiring layer on the interlayer insulating film.
Contact with the substrate surface through the contact hole
For manufacturing a semiconductor device, the method including:
The oxide formed on the bottom surface of the contact hole
And the silicide film are etched using a halogen-based gas.
This includes a step of removing the film by polishing.

The present invention (Claim 2) is characterized in that:
In the method for manufacturing a semiconductor device, the halogen-based gas
Gas that forms a fluorocarbon polymer
Only the oxide generated on the bottom of the contact hole
After selective removal, use a predetermined halogen-based gas to remove
Including the step of removing the silicide film on the bottom of the contact hole.
It is no thing.

The present invention (Claim 3) is characterized in that:
In the method for manufacturing a semiconductor device, the contact hole
After removing the oxide and silicide film generated on the bottom surface,
Inert gas atmosphere without exposing the silicon substrate
Form the above wiring layer while maintaining the atmosphere or vacuum
It is those that.

[0023]

According to the present invention, interlayer insulation on a silicon substrate is provided.
Oxidation on the bottom of the contact hole formed in the edge film
The material and the silicide film are etched using a halogen-based gas.
By removing the contact, the core contacting the wiring layer
The oxide generated on the bottom of the contact hole is completely removed.
You. This makes it possible to obtain a stable ohmic
Reproducibility of semiconductor devices with contacts with characteristic
Can be easily obtained.

Further, the oxide and the silicide film are removed.
Contact with the contact hole without opening to the atmosphere
By forming a wiring layer to be formed,
The bottom surface of the tact hole is not oxidized again. to this
More stable ohmic contact
The semiconductor device provided can be easily obtained with good reproducibility .

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 4 to FIG. 6 indicate the same or corresponding portions. First, as shown in FIG. 1A, a P-type silicon substrate or a P-well region 1 on the silicon substrate is provided with, for example, 600 nm for element isolation. A thick silicon oxide film 2, a P-type channel cut layer formed by boron ion-implanted before oxidation, and an n-type impurity diffusion layer 4 formed by heat treatment at 900 ° C. for 30 minutes after arsenic ion implantation. Then, a titanium silicide film 6 is formed on the n-type impurity diffusion layer 4 in a self-aligned manner by a lamp annealing method, and a silicon oxide film 7 is formed as an interlayer insulating film by, for example, a 200-nm-thick low-pressure CVD method. Until the direct contact 8 is formed by lithography and dry etching using a freon-based etching gas, the conventional example shown in FIG. If it is the same as.

Next, in this state, the titanium silicide film 6 in the contact 8 is etched by performing etching using a gas for forming a fluorocarbon polymer, for example, methane trifluoride, as shown in FIG. Surface oxide 6a
Is selectively removed to expose the surface of the titanium silicide film 6.

Thereafter, similarly to the conventional example, after performing a pretreatment with sulfuric acid or the like, a phosphorus-doped polycrystalline film into which phosphorus ions are introduced as impurities is removed by, for example, a low pressure CVD method.
After depositing 0 nm, a phosphorus-doped polycrystalline silicon film 9 is formed only in a desired portion by a photolithography method and a dry etching method to form a wiring layer (see FIG. 1C). At this time, since the oxide 6a formed by oxidizing the titanium silicide film 6 does not exist at the interface between the phosphorus-doped polycrystalline silicon film 9 and the n-type impurity diffusion layer 4 on the surface of the silicon substrate 1, good ohmic characteristics can be easily obtained. Can be obtained with good reproducibility.

FIG. 2 shows a second embodiment of the present invention, in which a contact is made on a silicided first wiring layer and a second wiring layer made of polysilicon is arranged. . As shown in FIG. 2, an interlayer insulating film made of a silicon oxide film 10
After forming a first polycrystalline silicon film 11 as a wiring layer and a titanium silicide film 12 by a silicidation reaction,
A direct contact 14 is provided, and a gas such as methane trifluoride is used as in the first embodiment.
After selectively removing the oxide on the titanium silicide film 12 therein, a second polycrystalline silicon film 15 is formed as a second wiring layer.

FIG. 3 shows a third embodiment of the present invention. Similar to the conventional example shown in FIG. 6, an n-type impurity diffusion layer 4 and a titanium silicide film 6 are formed on a silicon substrate 1. After that, an interlayer insulating film 7 is deposited, a contact 16 having a tapered shape is formed, and an oxide formed on the surface of the titanium silicide film 6 in the contact 16 is selected using a gas such as methane trifluoride. After the removal, the aluminum wiring layer 17 of an aluminum alloy film is formed.

As described above, in the first to third embodiments, when the contact is provided on the silicide film and the wiring layer made of polysilicon or metal is provided, the oxidation generated in the portion of the silicide film exposed in the contact is provided. Since the material is selectively removed using a gas that forms a fluorocarbon polymer such as methane trifluoride, a contact having a stable ohmic characteristic can be obtained with good reproducibility. Since the silicide film remains in a portion where the layer takes ohmic contact, lower ohmic characteristics can be obtained.

[0031]

In the first to third embodiments, methane trifluoride is used as the gas for forming the fluorocarbon polymer. However, other than this, for example, a mixed gas of carbon tetrafluoride and hydrogen may be used. The effect of can be obtained.

Next, a fourth embodiment of the present invention will be described. In this embodiment, after the oxide formed on the silicide film at the bottom of the contact is selectively removed, the silicide film below the oxide is also removed, as shown in FIG. The steps up to) are the same as those shown in FIG. 1 (b) of the first embodiment. Next, as shown in FIG. 7 (b), a freon-based gas such as By performing etching using a mixed gas of carbon (CF4) and oxygen (O2), the titanium silicide film 6 in the contact 8 is directly removed to expose the surface of the silicon substrate 1.

Thereafter, in the same manner as in the first embodiment,
After performing a pretreatment with sulfuric acid or the like, the phosphorus-doped polycrystalline film into which phosphorus ions are introduced as impurities is removed, for example, under reduced pressure CV.
After depositing 100 nm by the method D, a phosphorus-doped polycrystalline silicon film 9 is formed only at a desired portion by a photolithography method and a dry etching method to form a wiring layer (see FIG. 7C). At this time, since the titanium silicide film 6 does not exist at the interface between the phosphorus-doped polycrystalline silicon film 9 and the n-type impurity diffusion layer 4 on the surface of the silicon substrate 1, the oxide 6a on the silicide film 6 is completely removed. Since the ohmic state is exactly the same as when a direct contact is made on the active region where silicidation is not performed, a direct contact having good ohmic characteristics can be easily obtained with good reproducibility.

Next, as a fifth embodiment of the present invention, as shown in FIG. 8, similar to the second embodiment shown in FIG.
After forming an interlayer insulating film of a silicon oxide film 10, a first polycrystalline silicon film 11 as a wiring layer, and a titanium silicide film 12 by a silicidation reaction on the silicon substrate 1, a direct contact 14 is provided to form a trifluoride. After the oxide on the titanium silicide film 12 in the direct contact 14 is selectively removed by using a gas such as methane, the mixed gas of carbon tetrafluoride (CF4) and oxygen (O2) is used. After removing the titanium silicide film 12, a second polycrystalline silicon film 15 is formed as a second wiring layer.

As a sixth embodiment, as shown in FIG. 9, a contact is made on an active region on a silicon substrate.
In the case of forming the metal wiring, the n-type impurity diffusion layers 4 and 4 are formed on the silicon substrate 1 in the same manner as in the third embodiment shown in FIG.
After each of the titanium silicide films 6 is formed, a silicon oxide film 7 is deposited as an interlayer insulating film, a tapered contact 16 is formed, and an oxide formed on the surface of the titanium silicide film 6 in the contact 16 is removed. After selective removal using a gas such as methane trifluoride, the titanium silicide film 6 in the contact 16 is removed using a mixed gas of carbon tetrafluoride (CF4) and oxygen (O2), and then an aluminum alloy film To form an aluminum wiring layer 17.

In the fourth to sixth embodiments, after the oxide 6a on the silicide film 6 in the contact is selectively removed by the method of the first to third embodiments,
Although the silicide film 6 in the contact is removed using a predetermined gas, the oxide 6a and the silicide film 6 can be removed simultaneously by using boron trichloride (BCl3) gas. The step of removing the oxide 6a can be omitted.

In the above embodiment, carbon tetrafluoride was used as an etching gas. However, other fluorine-based gases such as sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3) were used.
) Gas or chlorine-based gas, for example, chlorine (Cl2
), Boron trichloride (BCl3), carbon tetrachloride (CCl4)
) May be used, and these etching gases have the ability to etch the silicon substrate 1 as well. However, the dry etching method has good controllability, so that the amount of the silicon substrate 1 actually etched is small. In this case, the junction between the n-type impurity diffusion layer 4 and the silicon substrate 1 is not broken.

Next, a seventh embodiment of the present invention will be described. As another method for selectively removing the oxide on the silicide film, there is a method for reducing the oxide. For example, number 10
Baking at 700 to 1100 ° C. in a mixed gas of hydrogen (H 2) or a mixed gas of hydrogen and a small amount of silane (SiH 4) or a mixed gas of hydrogen and a small amount of disilane (Si 2 H 6) under a pressure of Torr to several Torr; For example, when the irradiation is performed by radiant heating using an infrared lamp or the like, the oxide is reduced, and the silicide film surface is exposed. The figure is the same as FIG.

As another method for removing the oxide film on the silicide film or removing the silicide film when the oxide is removed, there is a so-called vapor phase etching method. This will be described below as an eighth embodiment. In this embodiment, for example, a mixed gas of hydrofluoric acid (HF) and steam, or hydrofluoric acid (HF) and anhydrous methyl alcohol (CH3 O) under a pressure of several tens Torr to several Torr.
Oxide on the surface of the silicide film can be removed by performing gas phase etching using a mixed gas of H) or isopropyl alcohol, or hydrofluoric anhydride (HF). Alternatively, there is a method in which a semiconductor device is placed in a mixed gas of hydrogen (H2) and a small amount of hydrofluoric acid (HF) and irradiated with ultraviolet light having a wavelength of several 100 nm, for example, 200 to 300 nm to remove oxides.

In particular, a nickel silicide film (NiSi 2,
The oxide (NiOx) on NiSi) is selectively removed by these hydrofluoric acid (HF) -based gas phase etching,
The nickel silicide film (NiSi2, NiSi) is not etched. In the case of another silicide film, for example, in the case of a titanium silicide film (TiSi2), by optimizing the etching amount, the oxide (TiOx) is removed to expose the underlying silicide film (TiSi2), or the silicide film (TiSi2) is further removed. TiSi2) can be entirely removed to expose the underlying silicon substrate. When the nickel silicide film (NiSi2, NiSi) is to be removed, hydrogen chloride (HCl) and hydrogen peroxide (H2 O
It can be removed by gas phase etching using a mixed gas of 2) and water vapor (H2 O).

Such a method of reducing oxides by gas and baking, or a method of removing oxides on the silicide film itself or the surface by vapor phase etching has an advantage that generation of particles is extremely small.

In the above description, the method of selectively removing the silicide film itself on the substrate surface or the oxide on the silicide film surface has been described. However, in the actual manufacture of a semiconductor device, a manufacturing apparatus, air or a human body may be used. Since there is contamination of organic matter, particularly carbon (C), it is necessary to add a step of removing carbon (C) before forming the wiring layer in order to more stably obtain an ohmic low-resistance contact. This will be described below as a ninth embodiment of the present invention.

In this embodiment, the semiconductor device is placed in ozone (O 3) at normal pressure (760 Torr) to several Torr, and a wavelength of several hundred nm, for example, 200 n using a mercury lamp.
A method of irradiating ultraviolet rays from m to 300 nm, or a method of placing a semiconductor device in a similar atmosphere and performing radiant heating using an infrared lamp or the like, both methods employ carbon (C) on the surface of a silicide film or an oxide film. Contamination can be removed.

The removal of an oxide film by a reduction method using hydrogen (H 2) or the like, and the removal of an oxide film and a silicide film itself by vapor phase etching are described in Low Temperature Silicate.
onSurface Cleaning by HF Etching / Ultraviolet Ozone
Cleaning (HF / UVOC) Method (I) -Optimizati
on of the HF Treatment-Maki SUEMITSU, et al., (Japa
nese Journal of Applied Physics Vol.28, No.12, Dece
mber, 1989, pp. 2421-2424), a silicon oxide film is described in detail as an example, and ozone (O3) and removal of carbon (C) contamination by ultraviolet rays are described in the literature on the case of a silicon surface. Temperature Silicon Surf
ace Cleaning by HF Etching / Ultraviolet Ozone Clean
ing (HF / UVOC) Methd (II) -in situ UVOC
−Tetsuya KANEKO, et al., (Ibid., Pp.2425-2429) describes the mechanism in detail.

Further, removal of the oxide and the silicide film itself from the surface of the silicide film after the etching or reduction,
Further, carbon (C) on the substrate surface before the subsequent formation of the wiring layer
Each of the above is described separately, but once the semiconductor substrate after removing these is once exposed to the air, the carbon (C) contamination and the formation of an oxide film on the surface of the silicide film, though to varying degrees, are again caused. May occur and the expected effect of the present invention may be impaired.

Therefore, in order to further enhance the expected effect, it is conceivable that the above-described steps are continuously performed using an apparatus as shown in FIG. Hereinafter, this will be described as an eleventh embodiment. That is, in the apparatus of FIG. 10, the silicon wafer 20 after the contact hole is formed
Reaction chamber 22 for removing carbon (C)
After passing through the transfer system 26, it is processed in the reaction chamber 23 for removing the oxide film or the silicide film itself on the surface of the silicide film through the transfer system 26, and further passed through the transfer system 27 in the film formation chamber 24. After forming a film, a barrier metal film or an aluminum alloy film, the film is carried out from the carry-out port 25.

At this time, the inside of the carry-out systems 26 and 27 is replaced with an inert gas such as nitrogen (N 2) in order to maintain the surface of the semiconductor device as it is in the reaction chambers 22 and 23. Or maintained at a vacuum of, for example, several hundred mm Torr.

When the oxide film on the surface of the silicide film or the silicide film itself is removed by using a gas containing carbon (C), a reaction chamber for removing carbon (C) is further arranged in the carrying-out system 27. Becomes

In each of the above embodiments, the phosphorus-doped polycrystalline silicon film 9 in which phosphorus ions are introduced into the polycrystalline silicon film as a wiring layer when the film is formed is used. A similar effect can be obtained without impairing the effect of the present invention by adopting a method of introducing phosphorus ions, arsenic ions, or the like into the film by depositing a polycrystalline silicon film that has not been subjected to ion implantation.

In each of the above embodiments, an example is described in which a contact is made on an n-type impurity diffusion layer on a silicon substrate or an n-type polycrystalline silicon film. The present invention can be similarly applied to a case where a contact is made on a film, and a similar effect can be obtained.

In each of the above embodiments, a titanium nitride (TiN) film, a titanium tungsten (TiW) film, a molybdenum silicide (Mo)
Needless to say, even when a so-called barrier metal film such as a Si2) film is used, the effect of the present invention is not impaired at all.

[0053]

As described above, according to the method of manufacturing a semiconductor device according to the present invention , a silicide film is formed on a silicon substrate.
After the formation of an interlayer insulating film, the interlayer insulating film is formed
Contact the above substrate surface through the contact hole
In the method of manufacturing a semiconductor device for forming a wiring layer,
Oxide and silicide formed on the bottom of the contact hole
The film is removed by etching using a halogen-based gas.
Is left on the bottom of the contact hole.
Oxide and the silicide film are completely removed.
With contacts with stable ohmic properties
There is an effect that a semiconductor device can be easily obtained with good reproducibility .

Further, the contact hole is formed on the bottom of the contact hole.
After removing the residual oxide and the silicide film,
Inert gas atmosphere without exposing the substrate
By forming the wiring layer while maintaining the vacuum state,
When the wiring layer is formed, the bottom of the contact hole is oxidized again.
Have more stable ohmic characteristics
There is an effect that a semiconductor device provided with a contact can be easily obtained with good reproducibility .

[Brief description of the drawings]

FIG. 1 is a view illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a view illustrating a method of manufacturing a semiconductor device according to a second embodiment of the present invention.

FIG. 3 is a view illustrating a method of manufacturing a semiconductor device according to a third embodiment of the present invention.

FIG. 4 is a view for explaining a conventional method for manufacturing a semiconductor device.

FIG. 5 is a view for explaining another conventional method for manufacturing a semiconductor device.

FIG. 6 is a view for explaining still another conventional method for manufacturing a semiconductor device.

FIG. 7 is a view illustrating a method of manufacturing a semiconductor device according to a fourth embodiment of the present invention.

FIG. 8 is a view illustrating a method of manufacturing a semiconductor device according to a fifth embodiment of the present invention.

FIG. 9 is a view illustrating a method of manufacturing a semiconductor device according to a sixth embodiment of the present invention.

FIG. 10 is a view showing a processing apparatus suitable for manufacturing a semiconductor device according to an eleventh embodiment of the present invention.

[Description of Signs] 1 silicon substrate or well region formed in silicon substrate 2 thick silicon oxide film for element isolation 4 n-type impurity diffusion layer 6 titanium silicide film 6a insulating oxide 12 titanium silicide film Reference Signs List 12a Oxide having insulation 8 Direct contact 14 Contact 20 Silicon substrate with contact hole formed 21 Carry-in port 22 Reaction chamber for removing carbon 23 Reaction chamber for removing oxide or silicide film 24 Wiring layer formation Chamber for transport 25 Loading port 26 Transport system 27 Transport system

Claims (3)

(57) [Claims] A step of forming a silicide film on a silicon substrate by a silicide reaction, forming an interlayer insulating film, forming a contact hole at a predetermined position in the interlayer insulating film, and thereafter, forming a wiring layer on the interlayer insulating film. , the method of manufacturing a semiconductor device including the step of forming in contact with the substrate surface through the contact hole, oxides generated on the contact hole bottom surface and Shirisai
A method of manufacturing a semiconductor device, comprising: removing a silicon nitride film by etching using a halogen-based gas. 2. A method for manufacturing a semiconductor device according to claim 1, wherein
Oite, as the halogen-based gas, fluorocarbon polymer
On the bottom of the contact hole using a gas that forms
After selectively removing only the oxides generated in
Silicide on the bottom of contact hole using gen-based gas
A method for manufacturing a semiconductor device, comprising a step of removing a film . 3. The method of manufacturing a semiconductor device according to claim 1 , wherein the oxide formed on the bottom surface of the contact hole and the silicide are formed.
After removing the silicon oxide film, the silicon substrate is opened to the atmosphere.
Without inert gas or vacuum
Forming a wiring layer by using the method described above .