JP3033525B2 - 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 MOS field effect transistor (MO).
SFET).

[0002]

2. Description of the Related Art Conventionally, in a MOSFET, a method of forming a silicide film on a substrate has been used as a method for lowering the resistance of a gate electrode or a source / drain region. As a manufacturing method, as shown in FIG. 4, first, a gate oxide film 3 and a polycrystalline silicon gate electrode 4 are formed on a silicon semiconductor substrate 1 on which an element isolation region 2 is formed (FIG. 4 (a)). 4) Then, as shown in FIG. 4 (b), an impurity such as arsenic or boron is ion-implanted into the gate electrode and the source and drain regions 5 and 6, and an activation heat treatment is performed. Next, as shown in FIG. 4 (c), after depositing a metal film on the substrate, heat treatment is performed to form a silicide film on silicon. Then, after selectively etching the metal film on the insulating film, a high-temperature heat treatment is performed again, and the silicide film 8 is formed.
2 is reduced in resistance.

[0003]

However, the first problem is, for example, that of 1994 / IEEE / Transacti.
on on Electron Devices 41
Vol. 12, No. 12, pp. 2305-2317, it is becoming difficult to reduce the resistance of a silicide film formed on a fine silicon region with miniaturization of a MOSFET.

[0004] Factors that are important for the formation of a low-resistance silicide film include, for example, a metal film as reported in Extended Abstracts, 1994, International Solid State Device, Device Conference, pp. 622-624. This is because the high concentration of oxygen contained on the silicon substrate surface prior to the deposition of silicide inhibits the silicidation reaction,
The second problem is that a high concentration of oxygen remains on the surface of the silicon substrate, and this oxygen is caused by a surface pretreatment method before depositing a metal film, knocking of oxygen from a cover oxide film at the time of impurity doping, and the like. .

Therefore, the problem to be solved by the present invention is to provide a MOS transistor in which a low-resistance silicide film is formed in a fine silicon region.
An object of the present invention is to form an FET to further improve the performance of a semiconductor device, particularly to achieve higher performance. SUMMARY OF THE INVENTION An object of the present invention is to provide a manufacturing method capable of realizing a semiconductor, particularly a MOS field effect transistor structure, which can solve these problems.

[0006]

Means for Solving the Problems The present inventors have made intensive studies in order to solve the above-mentioned problems, and have reached the present invention. That is, the present application includes the following inventions.

A semiconductor substrate has an insulating film serving as a gate insulating film, a gate electrode is formed on the insulating film, and an impurity-containing substrate in which impurities are introduced into the gate electrode and source / drain regions is heated to a substrate temperature. 500-600 a metal film is deposited on a substrate at a high temperature of ° C., the unreacted metal film on the insulating film on the substrate deposited the metal film is selectively removed, then the silicide film on the substrate 600 to 800 In a method of producing a semiconductor by heat treatment at a high temperature of about 500 ° C., the substrate containing
A method for manufacturing a semiconductor device, comprising a step of performing a heat treatment of a substrate in an oxygen gas or oxygen plasma at 500 to 1000 ° C. before a surface treatment step of heat treatment at 1000 ° C.

(1) a step of forming an insulating film to be a gate insulating film on a semiconductor substrate; (2) a step of forming a gate electrode on the insulating film; and (3) an impurity in the gate electrode and the source / drain regions. Step of Introducing (4-1) Substrate 5 in oxygen gas or oxygen plasma
A first surface treatment step of heat treatment at 00~1000 ℃ (4-2) 5 the substrate with hydrogen gas or hydrogen plasma
00-1000 and a second surface treatment step of heat treatment at ° C. (5) step and (6) unreacted metal on the substrate an insulating film substrate temperature for depositing a metal film on a substrate at a high temperature of 500 to 600 ° C. The method for manufacturing a semiconductor device according to claim, further comprising: a step of selectively removing the film; and (7) a step of heat-treating the silicide film on the substrate at a high temperature of 600 to 800 ° C.

In the above-mentioned manufacturing method, the substrate temperature may be 5
The method of manufacturing a semiconductor device according to any one of claims 1 to 3, wherein in the step of depositing the metal film on the substrate having a high temperature of 00 to 600 ° C , the film deposition atmosphere is a hydrogen-containing atmosphere.

[0010] A method of manufacturing a semiconductor device, wherein the semiconductor device according to any one of the above is a MOS field effect transistor.

[0011]

[0012]

[0013]

The method of manufacturing a semiconductor device according to the present invention will be described. The present invention is based on an experimental result on a silicidation reaction. First, as shown in FIG. 5, by reducing the oxygen concentration on the silicon substrate surface, a silicidation reaction with a metal film deposited on silicon can be promoted. Further, oxygen on the surface of the silicon substrate and in the vicinity thereof can be largely removed by heat treatment in a hydrogen atmosphere. Oxygen in the vicinity of the silicon substrate is once oxidized together with the silicon substrate by a heat treatment in an oxygen atmosphere, and can be efficiently removed from the substrate surface and the vicinity by a subsequent heat treatment in a hydrogen atmosphere.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the step of forming an insulating film serving as a gate insulating film on a semiconductor substrate in the method of manufacturing a semiconductor according to the present invention, silicon is used for the semiconductor substrate, and the insulating film is a silicon nitride film, a silicon oxide film or a silicon oxide film. A silicon oxynitride film or the like is used.

In the step of forming polycrystalline silicon or amorphous silicon as a gate electrode on the insulating film and the step of introducing impurities into the gate electrode and the source / drain regions, a group III element, a group V element or These fluorides are used, and arsenic or boron is particularly preferably used, and the introduced amount is 1 × 10 ^{14 to} 1 × 10 ⁴ .
¹⁶ cm ^-2 range, preferably 1 × 10 ^{15 to} 5 × 10 ¹⁵ c
m- ² .

When the substrate is heat-treated in the hydrogen gas or hydrogen plasma of (4) or (4-2) of the present invention, the case of using a mixed gas of hydrogen and an inert gas such as argon is also included. The heat treatment temperature is 500-1000 ° C,
Preferably 600 to 800 ° C, treatment time is 1 to 30 minutes,
Preferably, it is 5 to 10 minutes.

Prior to the above (4-2), (4-
1) The first surface treatment step in which the substrate is heat-treated in oxygen gas or oxygen plasma includes the case where oxygen or a mixed gas containing oxygen is used in the heat treatment. The heat treatment temperature is 500 to 1000 ° C, preferably 600 to 1000 ° C.
950 ° C., treatment time 5-20 seconds, preferably 10-1
5 seconds.

The pressure of hydrogen at the time of the hydrogen surface treatment is 0.1 to 10 torr, preferably 1 to 2 torr, and the pressure of oxygen at the time of oxygen surface treatment is 0.5 to 5 mt.
orr, preferably about 1 mtorr.

Each of the steps other than (4), (4-1) and (4-2) can be performed by a known ordinary method usually used for manufacturing a semiconductor, and there is no particular limitation. The obtained surface-treated substrate is at a high temperature, preferably 500 to 60.
0 ° C., a step of depositing a metal film (for example, titanium, cobalt or nickel) on the substrate by a sputtering method, a step of selectively removing the metal film on the insulating film of the substrate, and a step of heating the silicide film on the substrate to a high temperature. A semiconductor device is manufactured by a step of performing a heat treatment at (for example, 600 to 800 ° C.).

Next, an embodiment of a method of manufacturing a semiconductor device according to the present invention will be described with reference to the drawings. FIG. 1 shows a MOSF showing a first embodiment of a method of manufacturing a semiconductor device of the present invention.
It is a process sectional view of ET. FIG. 1A shows that a gate insulating film 3 and a polycrystalline silicon gate electrode 4 are formed on a silicon semiconductor substrate 1 on which an element isolation region 2 is formed, and impurities are introduced into the gate electrode and source / drain regions 5. And
Indicates an activated state. Next, as shown in FIG. 1 (b), the substrate is heat-treated in a hydrogen gas or plasma atmosphere. By this heat treatment, the high-concentration oxygen region 71 at and near the substrate surface shown in FIG. Further, as shown in FIG. 1 (c), a metal film is deposited on the surface of the substrate while the substrate is heated. By this metal film formation, a silicidation reaction occurs with the metal film on the silicon surface, and a high-resistance silicide film 81 is formed. Further, after the formation of the metal film, the unreacted metal film on the insulating film is selectively etched. Finally, as shown in FIG. 1D, heat treatment is performed in an inert gas atmosphere to reduce the resistance of the silicide film 82, thereby completing the semiconductor device.

Next, a second embodiment of the method of manufacturing a semiconductor device of the present invention will be described with reference to FIG. FIG. 2A shows that a gate insulating film 3 and a polycrystalline silicon gate electrode 4 are formed on a silicon semiconductor substrate 1 on which an element isolation region 2 is formed, and impurities are introduced into the gate electrode and source / drain regions 5. And shows the activated state. Then the second
As shown in FIG. (B), the substrate was heat-treated substrate with oxygen gas or oxygen plasma, changing the incomplete oxidation region of the substrate near the complete silicon oxide film 9. Next, as shown in FIG. 2C, the substrate is heat-treated in a hydrogen gas or plasma atmosphere. By this heat treatment, oxygen on the substrate surface and in the vicinity is reduced. Further, FIG. 2 (d)
As shown in (2), a metal film is deposited on the substrate surface while the substrate is heated. By this metal film formation, a silicidation reaction occurs with the metal film on the silicon surface, and a high-resistance silicide film 81 is formed. Further, after the formation of the metal film, the unreacted metal film on the insulating film is selectively etched. Finally, the second
As shown in FIG. 3E, heat treatment is performed in an inert gas atmosphere to reduce the resistance of the silicide film 82, thereby completing the semiconductor device.

Next, a third embodiment of the method of manufacturing a semiconductor device according to the present invention will be described with reference to FIG. FIG. 3A shows that a gate insulating film 3 and a polycrystalline silicon gate electrode 4 are formed on a silicon semiconductor substrate 1 on which an element isolation region 2 is formed, and impurities are introduced into the gate electrode and source / drain regions 5. And shows the activated state. Then the third
As shown in FIG. 2B, the substrate is heat-treated in a hydrogen gas or plasma atmosphere. This heat treatment can significantly reduce oxygen on the substrate surface and in the vicinity. However, a region 72 containing oxygen at a low concentration remains. Further, as shown in FIG. 3 (c), a metal film is deposited on the substrate surface in an argon gas atmosphere mixed with hydrogen while the substrate is heated. Due to the formation of the metal film, a silicidation reaction occurs with the metal film on the silicon surface, and the high-resistance silicide film 8 is formed.
1 is formed. Further, after the formation of the metal film, the unreacted metal film on the insulating film is selectively etched. Finally, as shown in FIG. 3D, heat treatment is performed in an inert gas atmosphere to form a low-resistance silicide film 82, thereby completing a semiconductor device.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. A first embodiment of the method for manufacturing a semiconductor device of the present invention will be described with reference to FIG. FIG. 1A shows that a gate oxide film 3 having a thickness of 7 nm and a polycrystalline silicon gate electrode 4 having a thickness of 300 nm are formed on a silicon semiconductor substrate 1 having an element isolation region 2 formed by a LOCOS method. Arsenic or boron 1 × in source / drain region 5
10 ¹⁵ cm ^-2 ~5x10 ¹⁵ cm ^-2 is introduced, in an activated state. At this time, a region 71 containing oxygen at a high concentration remains on the surface of the silicon substrate. Next, as shown in FIG. 1B, after evacuating, a hydrogen gas is introduced in a 1 Torr atmosphere, and a heat treatment at 700 ° C. is performed to remove the substrate surface region 71 containing oxygen at a high concentration. Further, as shown in FIG. 1 (c), after depositing a titanium film to a thickness of 40 nm by sputtering with the substrate heated to 600 ° C., the unreacted titanium film on the substrate surface is selectively treated with a hydrogen peroxide solution. Etch. In this state, a high-resistance silicide film 81 is formed on silicon. Finally, as shown in FIG.
A heat treatment at 0 ° C. is performed to form a low-resistance silicide film 82 to complete a semiconductor device.

Next, another embodiment of the method of manufacturing a semiconductor device according to the present invention will be described with reference to FIG. FIG. 2 (a)
On a silicon semiconductor substrate 1 in which an element isolation region 2 is formed by a trench method, 5 nm-thick gate nitrided oxide films 3 and 200 are formed.
forming a polysilicon gate electrode 4 nm, further arsenic or boron 1x10 ¹⁵ cm ^-2 ~3x10 ¹⁵ cm ^-2 is introduced into the gate electrode and the source / drain regions 5, showing the activated state. Next, as shown in FIG. 2B, after evacuating, an oxygen gas is introduced in a 1 mTorr atmosphere, a heat treatment at 600 ° C. is performed, and the surface is oxidized by about 1 nm to form an oxide film 9.

Thereafter, as shown in FIG. 2C, after evacuating, a hydrogen gas is introduced in a 1 Torr atmosphere, and a heat treatment at 750 ° C. is performed to remove an oxide film and oxygen on the silicon surface. Further, as shown in FIG. 2 (d), after a titanium film is deposited to a thickness of 30 nm by sputtering while the substrate is heated to 550 ° C., the unreacted titanium film on the substrate surface is selectively treated with a hydrogen peroxide solution. Etch. In this state, the high-resistance silicide film 81 is formed on the silicon.
Are formed. Finally, as shown in FIG. 2E, heat treatment is performed at 750 ° C. in a nitrogen gas atmosphere to lower the resistance of the silicide film to form a low-resistance silicide film 82, thereby completing the semiconductor device.

Next, another embodiment of the method of manufacturing a semiconductor device according to the present invention will be described with reference to FIG. FIG. 3 (a)
A 4 nm-thick gate oxynitride film 3 and 200
forming a polysilicon gate electrode 4 nm, further arsenic or boron 1x10 ¹⁵ cm ^-2 ~2x10 ¹⁵ cm ^-2 is introduced into the gate electrode and the source / drain regions 5, showing the activated state. Next, as shown in FIG. 3 (b), after evacuating, a hydrogen gas is introduced in a 1 Torr atmosphere, and a heat treatment at 600 ° C. is performed. In this state, a region 72 containing oxygen at a low concentration remains on the silicon surface.

Further, as shown in FIG. 3 (c), a titanium film was deposited to a thickness of 20 nm by sputtering in a mixed gas atmosphere of hydrogen and argon while the substrate was heated to 500 ° C. The reactive titanium film is selectively etched with a hydrogen peroxide solution. At this time, a high-resistance silicide film 81 is formed on the silicon surface. Finally, as shown in FIG.
A heat treatment at 50 ° C. is performed to reduce the resistance of the silicide film to form a low-resistance silicide film 82, thereby completing the semiconductor device.

[0028]

The first effect of the present invention is that, in the present invention, a low-resistance silicide film can be uniformly formed in a fine silicon region. The resistance of the silicide film can be reduced by using the method of the present invention, as described in JP-A-2-31427, “Method of Manufacturing Semiconductor Device” and JP-A-3-155564, “MOS
There is an advantage that the resistance of a silicide film formed in a minute region which cannot be formed by a silicide film described in “Method of Manufacturing Type Semiconductor Device” can be reduced.

A second effect of the present invention is that, in the present invention, in order to remove oxygen on the silicon surface and in the vicinity thereof, heat treatment in hydrogen gas or plasma is performed to remove the surface oxygen, and thereby the metal film is removed. Therefore, the silicidation reaction of the silicon film can be promoted, and as a result, there is an advantage that the resistance of the silicide film formed in the fine silicon region can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a schematic sectional view showing a second embodiment of the method for manufacturing a semiconductor device according to the present invention.

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

FIG. 4 is a schematic cross-sectional view showing a method for forming a silicide film in a conventional semiconductor device.

FIG. 5 is a diagram showing the relationship between the oxygen concentration on the surface of a silicon substrate and the sheet resistance of a formed silicide film.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 silicon substrate 2 element isolation oxide film 3 gate oxide film 4 gate electrode 5 gate side wall insulating film 6 source / drain region 71 region containing high concentration of oxygen 72 region containing low concentration of oxygen 81 high resistance silicide film 82 low Resistance silicide film 9 Oxide film by thermal oxidation

Claims (4)

(57) [Claims] An impurity-containing substrate having an insulating film serving as a gate insulating film over a semiconductor substrate, a gate electrode formed on the insulating film, and an impurity introduced into the gate electrode and source / drain regions. temperature a metal film is deposited on a substrate at a high temperature of 500 to 600 ° C., the unreacted metal film on the insulating film on the substrate deposited the metal film is selectively removed, then the silicide film on the substrate 600 In a method for producing a semiconductor by heat treatment at a high temperature of from 800 to 800 ° C., before the surface treatment step of heat treating the impurity-containing substrate in a hydrogen gas or hydrogen plasma at 500 to 1000 ° C., an oxygen gas or an oxygen plasma is used. 50 substrates in
A method for manufacturing a semiconductor device, comprising a surface treatment step of performing heat treatment at 0 to 1000 ° C. And (2) a step of forming an insulating film to be a gate insulating film on the semiconductor substrate; (2) a step of forming a gate electrode on the insulating film; and (3) a step of forming a gate electrode and a source / drain region. 5 the substrate in step a (4-1) oxygen gas or oxygen plasma to introduce the impurity
A first surface treatment step of heat treatment at 00~1000 ℃ (4-2) 5 the substrate with hydrogen gas or hydrogen plasma
00-1000 and a second surface treatment step of heat treatment at ° C. (5) step and (6) unreacted metal on the substrate an insulating film substrate temperature for depositing a metal film on a substrate at a high temperature of 500 to 600 ° C. 2. The method according to claim 1, further comprising the steps of: selectively removing the film; and (7) heat-treating the silicide film on the substrate at a high temperature of 600 to 800 [deg.] C. 3. The method according to claim 1, wherein the substrate temperature is 50.
3. The method according to claim 1, wherein in the step of depositing the metal film on the substrate at a high temperature of 0 to 600 [deg.] C. , the film deposition atmosphere is a hydrogen-containing atmosphere. A method for manufacturing a semiconductor device. 4. A method for manufacturing a semiconductor device, wherein the semiconductor device according to claim 1 is a MOS field effect transistor.