JP2000200762A - Manufacture of semiconductor device and semiconductor manufacture device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a nitride tungsten film whose adhesive strength with a base is high by bringing first raw material gas into contact with an object to be processed before the nitride tungsten film is formed. SOLUTION: For forming a nitride tungsten WNx film on a semiconductor wafer W by using first raw material gas containing a tungsten atom, WF6 gas, for example, and second raw material gas containing a nitrogen atom, NH3 gas, for example, WF6 gas is brought into contact with the surface of the semiconductor wafer W before the WNx film is formed. Thus, WF6 gas and Ar gas are individually supplied into a chamber 20 from a shower head 10 by a prescribed flow rate for prescribed time before the WNx film is formed in a state where the shower head 10 and the chamber 20 are set to a prescribed temperature. The processing pressure of the semiconductor wafer W is set to prescribed one, and the surface processing of a polysilicon film by WF6 gas is executed. Thus, adhesive strength of the WNx film to the semiconductor wafer W is improved and the WNx film is prevented from being peeled from the semiconductor wafer W in a thermal processing process after the film is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device and a semiconductor manufacturing apparatus, and more particularly to a method of manufacturing a semiconductor device for forming a tungsten nitride (WN _x ) film used as various wirings, barrier metals or electrodes. The present invention relates to a method and a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Along with miniaturization of a semiconductor device, the gate of a semiconductor device such as a field-effect transistor has a high resistance. Therefore, there is a demand for an electrode wiring material capable of suppressing the resistance even more than before even if the gate structure is miniaturized. A high melting point metal silicide film such as tungsten silicide has been used in place of the conventional conductive polycrystalline silicon film. A tungsten film whose value can be reduced is considered promising.

When a tungsten film is used as an electrode, a structure in which a gate oxide film, a polysilicon film, and a tungsten film are sequentially laminated is adopted. In the heat treatment (850 to 900 ° C.) step, the two react at the interface between the polysilicon film and the tungsten film to form tungsten silicide (WSi) and increase the resistance of the electrode. If the reaction at the interface is significant, tungsten diffuses further and breaks through the gate oxide film and reacts with the silicon substrate, causing problems such as increasing the leakage current of the transistor and lowering the breakdown voltage. Let it.

Therefore, when a tungsten film is used as an electrode, a refractory metal nitride film such as tungsten nitride or titanium nitride is provided as a barrier film between the tungsten film and the polysilicon film, and the tungsten and polysilicon layers are formed by the barrier film. It is common to prevent the reaction. When a tungsten nitride film and a titanium nitride film as such a gate barrier film are compared, the tungsten nitride film has a high heat-resistant temperature, can obtain a crystal phase other than columnar crystals, and has a tungsten film on the tungsten nitride film. It is promising, because it is possible to grow the crystal grains of the crystal greatly and to lower the resistance. On the other hand, a titanium nitride film can usually only obtain columnar crystals, so there is a limit to increasing the crystal grain size of the tungsten film.

The following techniques are known as methods for producing a tungsten nitride film that is promising as a gate barrier film. WF ₆ gas and NH ₃ plasma CVD method using a thermal CVD method WF ₆ gas and NH ₃ gas using a gas (for example, JP 64-50515 JP) WF ₆ gas, N ₂ gas, H ₂ gas Plasma CVD method used (for example, JP-A-64-50515) Plasma CVD method using WF ₆ gas and NF ₃ gas (Suzuki
et.al, "Advanced Metalization and Innterconnect Sy
stems for ULSI Application in 1997 "Mter.Res.Soc..1
998,49) Thermal CVD method using an organic tungsten source (Sun et.
al., Proc. of 13th VMIC, 151, 1996)

[0006]

However, the film forming technique by the thermal CVD method requires a high film forming temperature exceeding 600 ° C., and thus may damage the diffusion layer of the transistor. In the film forming technique of this point, the film forming temperature is 450
Although there is no problem as in the case of ５００500 ° C., since the film forming technique of プ ラ ズ マ uses plasma, it is liable to be damaged near the gate electrode, and is inferior in coverage properties in via holes and the like, and is liable to cause film forming defects. In addition, there is a problem that the apparatus cost is high because plasma is used. Is a thermal CVD method that does not require plasma, so there is no problem as in the plasma CVD method, but
There is a problem that the resulting tungsten nitride film has a higher specific resistance than the plasma CVD method. After the film formation, tungsten is formed by thermal CVD, and then, for example, 80
When the heat treatment is performed at 0 to 900 ° C. for 60 seconds, there is a problem that the tungsten film is separated from the tungsten nitride film during the heat treatment.

Therefore, when a tungsten nitride film is used as the gate barrier film, the thermal CVD method using WF ₆ gas and NH ₃ gas is preferable as the tungsten nitride film formation method as described above. In the case of the method, as described above, there is a problem that the tungsten film is easily peeled off in the heat treatment step after the film formation, and the specific resistance of the tungsten nitride film is increased.

[0008] In the case of conventional film-forming methods, it may contain a high concentration of fluorine in the WN _X film after the film formation, since the fluorine adversely affect the reliability after the semiconductor device completed In addition, film forming conditions for lowering the fluorine concentration in the film are required.

Further, holes are often formed on the surface of the base during film formation. In such a case, an excellent film is formed at the bottom of the hole as well as the flat portion. Coverability (bottom coverage) is required. At this time, the ratio of the thickness of the bottom to the thickness of the flat portion (thickness of the bottom / thickness of the flat portion) is 70% as a measure of the coverage.
It is desirable that this is the case.

After the formation of the tungsten nitride film,
In many cases, various heat-loading steps are performed. At this time, it is necessary to have sufficient adhesion between the tungsten nitride film and the base so that film peeling does not occur. Furthermore, when a tungsten nitride film is used for an electrode portion of a capacitor, it is required that the leakage current be small and that a Schottky barrier be formed between the film and the insulating film. Further, when a tungsten nitride film is used as a barrier layer interposed between different materials, a barrier property for suppressing the diffusion of those materials is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a semiconductor device manufacturing method and a semiconductor manufacturing apparatus capable of forming a tungsten nitride film satisfying the above-mentioned various requirements. The purpose is.

[0012]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, wherein a target material is nitrided by using a first source gas containing tungsten atoms and a second source gas containing nitrogen atoms. In a method for manufacturing a semiconductor device by forming a tungsten film, a first source gas is brought into contact with the object before forming the tungsten nitride film.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the first aspect, wherein the first source gas is brought into contact with the object before film formation. The processing pressure of the object is set to 0.1 to 20 Torr, and the processing temperature of the object is set to 300 to 500 ° C.
And the flow rate of the first source gas is 0.5 to 10 sc
cm or the partial pressure of the first source gas is 5 × 10 ^{−4 to} 10 Torr
Is set.

According to a third aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the first or second aspect, wherein the tungsten nitride film is formed by using a first source gas and a second source gas. As a condition for forming, the processing pressure of the object to be processed is set to 0.1 to 50 Torr, the temperature of the object to be processed is set to 300 to 650 ° C., and the first
The flow rate of the source gas is set to 0.5 to 100 sccm, or the partial pressure of the first source gas is set to 5 × 10 ^{−4 to} 50 Torr, and the flow rate of the second source gas is set to 20 to 1000 sccm. It is.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to any one of the first to third aspects, wherein tungsten hexafluoride is used as the first source gas. In addition, ammonia gas is used as the second source gas.

According to a fifth aspect of the present invention, there is provided a semiconductor manufacturing apparatus, comprising: a gas supply mechanism for supplying a source gas; a film formation chamber connected to the gas supply mechanism; And a temperature-adjustable holding body for holding the object to be processed, and an exhaust unit for exhausting a gas after film-forming processing of the object held by the holding body, wherein tungsten atoms are used as the source gas. Containing first source gas and second containing nitrogen atoms
In an apparatus for supplying a source gas and forming a tungsten nitride film on the object to be processed in the film formation chamber, the gas supply mechanism includes a first and a second flow through which a first and a second source gas respectively flow. An inlet, first and second outlets respectively communicating with the first and second inlets to allow the first and second source gases to flow out individually, and a pressure for adjusting the pressure in the film forming chamber. An adjusting mechanism is provided in the film forming chamber or the exhaust unit.

According to a sixth aspect of the present invention, in a method of manufacturing a semiconductor device, a tungsten nitride film is formed on an object using a first source gas containing tungsten atoms and a second source gas containing nitrogen atoms. In the method of manufacturing a semiconductor device by forming, before forming the tungsten nitride film, a gas containing one of the first and second source gases is brought into contact with the surface of the object to be processed. is there.

According to a seventh aspect of the present invention, in a method of manufacturing a semiconductor device, a tungsten nitride film is formed on a workpiece using a first source gas containing tungsten atoms and a second source gas containing nitrogen atoms. In the method for manufacturing a semiconductor device by forming a tungsten nitride film, a gas containing silicon atoms is added during the formation of the tungsten nitride film to form the tungsten nitride film.

Further, in the method of manufacturing a semiconductor device according to claim 8 of the present invention, a tungsten nitride film is formed on an object using a first source gas containing tungsten atoms and a second source gas containing nitrogen atoms. In the method for manufacturing a semiconductor device by forming a film, a gas containing a gas containing silicon atoms is brought into contact with the tungsten nitride film after the formation of the tungsten nitride film.

According to a ninth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to any one of the sixth to eighth aspects, wherein the nitrogen concentration in the surface layer of the tungsten nitride film is increased. It is characterized by including.

According to a tenth aspect of the present invention, in the method for manufacturing a semiconductor device according to the ninth aspect, the step of increasing the nitrogen concentration in the surface layer of the tungsten nitride film is performed by using a gas containing nitrogen atoms. It is characterized by performing annealing in an atmosphere or plasma irradiation of a gas containing a nitrogen atom.

According to a eleventh aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the seventh or eighth aspect, further comprising a step of oxidizing a surface of the tungsten nitride film. Is what you do.

According to a twelfth aspect of the present invention, in the method for manufacturing a semiconductor device according to the eleventh aspect, the step of oxidizing the surface of the tungsten nitride film is performed in an oxygen or gas atmosphere containing oxygen. Forming silicon oxide on the surface of the tungsten nitride film by annealing.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in FIG. First, a thermal CVD film forming apparatus (hereinafter, simply referred to as a “film forming apparatus”) suitably used in the method of manufacturing a semiconductor device according to the present invention will be described with reference to FIG. As shown in FIG. 1, for example, the film forming apparatus according to the present embodiment includes a gas supply mechanism (shower head) 10 that supplies a raw material gas and a substantially cylindrical air-tight structure that is connected to the shower head 10. A chamber (chamber) 20, a temperature-adjustable holder (susceptor) 30 which is disposed at the center of the chamber 20 and horizontally holds an object (for example, a semiconductor wafer) W, and is held by the susceptor 30. And an exhaust pipe 40 for exhausting the gas after the film formation processing of the semiconductor wafer W. Therefore, the first source gas containing tungsten atoms (for example, tungsten hexafluoride (WF ₆ ) gas or the like) and the second source gas containing nitrogen atoms (for example, ammonia (NH ₃ ) When a gas or the like is supplied, a tungsten nitride film can be formed on the semiconductor wafer W. The flow rate of each source gas is controlled by a mass flow controller (not shown). In FIG. 1, reference numeral 31 denotes a support member for supporting the susceptor 30.

As shown in FIG. 1, the shower head 10 passes through the center of the upper wall of the chamber 20, and the lower surface thereof is parallel to the susceptor 30. Further, the shower head 10 is formed by integrating upper and lower three-stage block bodies 10A, 10B, and 10C. WF is on the upper surface of the upper block body 10A.
The first and second gas supply sources 50 and 60 of the ₆ gas and the NH ₃ gas are connected via respective pipes 51 and 61, respectively.
Gas inlets 11 and 12 are formed. Each of the gas inlets 11 and 12 is branched in the upper block body 10A to form first and second branch gas passages 11A and 12A, respectively, and each of the branch gas passages 11A and 12A is connected to the upper block body 1A.
The openings are uniformly distributed over the entire lower surface of 0A. The first and second branch gas passages 11 are provided on the upper surface of the middle block body 10B.
A and 12A are formed with first and second middle gas passages 11B and 12B communicating with the respective openings.
1B and 12B respectively penetrate the middle block body 10B and open at the lower surface of the middle block body 10B. The first and second middle gas passages 11 are provided on the upper surface of the lower block body 10C.
B, 12B, the first and second lower gas passages 11C, 12C communicating with the respective openings are formed.
1C and 12C are uniformly distributed and opened on the entire lower surface of the lower block body 10C. Therefore, when the WF ₆ gas and the NH ₃ gas are supplied from the gas supply sources 50 and 60, the respective gases flow into the shower head 10 from the first and second gas inlets 11 and 12, and then the lower gas flow path 11C, 12C, they are separately dispersed and flow out, and are uniformly mixed for the first time in the chamber 20 to prevent the reaction of each raw material gas in the shower head 10.

The showerhead 10 has a third gas inlet 13 connected to a chlorine trifluoride (ClF ₃ ) gas supply source 70 via a pipe 71, and a first gas inlet 13 and a second gas inlet 1.
The ClF ₃ gas formed in the same manner as 1 and 12 and flowing into the shower head 10 from the third gas inlet 13 flows into the upper gas flow path 12A and is supplied from the lower gas flow path 12C into the chamber 20 as a cleaning gas. It is like that.
At this time, from the viewpoint of improving the cleaning effect, ClF ₃
Instead of flowing the gas into the upper gas flow path 12A, the gas may flow into the first branch gas flow path 11A and be supplied from the lower gas flow path 11C into the chamber 20, or the upper gas flow path 12A and the first The gas may flow into both of the branch gas flow paths 11A, and may be supplied into the chamber 20 from both of 12C and 11C. However, in the latter case, WF
_A check valve (not shown) or the like is required so that the ₆ gas and the NH ₃ gas are not directly mixed. Although not shown, the shower head 10 uses an inert gas such as an argon (Ar) gas or a nitrogen gas as a gas for diluting the raw material gas.
A gas inlet for supplying the gas into the chamber is formed.

A shower head heater 14 is mounted on the upper surface of the shower head 10, and controls the temperature of the shower head 10 with the heater 14, so that the temperatures of the raw material gas, the cleaning gas, and the dilution gas are controlled in the shower head 10. Each is adjusted to a predetermined temperature, and the chamber 20 is adjusted.
In addition, the reaction by-product is prevented from adhering to the surface of the shower head in the chamber 20. Further, a chamber heater 21 is disposed on the outer surface of each of the peripheral wall and the upper and lower walls of the chamber 20, and the heater 21 controls the inner wall surface of the chamber 20 to a predetermined temperature to adhere reaction by-products to the inner wall surface. Has been prevented. The shower head heater 14 and the chamber heater 21 can be individually controlled under the control of a controller (not shown).

A guide ring 32 for guiding a semiconductor wafer W loaded from a transfer mechanism (not shown) to the center of the susceptor 30 is provided at an outer peripheral edge of the susceptor 30 in the chamber 20. A stage heater 80 for controlling the temperature of the heater is embedded.
A power supply 81 and a controller 82 are connected to the stage heater 80, and the power supply 81 supplies power to the stage heater 80 under the control of the controller 82.

A vacuum pump 90 is connected to the exhaust pipe 40. Further, the exhaust pipe 40 is provided with a valve 91 for adjusting the degree of opening of its flow path as an opening adjustment mechanism. By adjusting the pressure, the pressure in the chamber 20 is appropriately adjusted. It is more desirable to install a trap as a trap mechanism on one or both of the inlet and the outlet of the pump 90 on the exhaust side, and to cool the trap to further enhance its collection efficiency. Further, a structure may be adopted in which the conductance on the exhaust side is reduced. A structure combining the above features may be used.

Next, a method for manufacturing a semiconductor device of the present invention using the film forming apparatus shown in FIG. 1 will be described. In the method of the present invention, the first source gas containing tungsten atoms (for example, WF
₆ gas) and a second source gas containing a nitrogen atom (for example, NH ₃ gas) is used to form tungsten nitride (W) on the semiconductor wafer W.
N _X ) When manufacturing a semiconductor device by forming a film, WN _X
It is characterized in that the WF ₆ gas is brought into contact with the surface of the semiconductor wafer W before the film is formed. The present invention method to enhance the adhesion to the semiconductor wafer W WN _X film, it is possible to prevent peeling from the semiconductor wafer W WN _X film in the heat treatment process after deposition.

In order to carry out the method of the present invention, first, the vacuum pump 90 is driven, the opening degree of the valve 91 is adjusted to evacuate the chamber 20 to a predetermined degree of vacuum, and the shower head heater 14 and the chamber The shower head 10, the chamber 20, and the susceptor 30 are heated to predetermined temperatures via the heater 21 and the stage heater 80, respectively. Then, preprocessing is performed in the chamber 20 prior to the film forming process WN _X film. WF ₆ gas in a state where the semiconductor wafer W is not present in it, each of the Ar gas and NH ₃ gas is supplied into the chamber 20 at a predetermined flow rate, to precoat the WN _X film susceptor and around the chamber 20. If this pretreatment is not performed, WF ₆ gas or NH ₃ gas is consumed in and around the susceptor at the initial stage of film formation on the semiconductor wafer W, and these gases do not reach the semiconductor wafer during the essential film formation. of it can not be formed a WN _X film.

When performing pretreatment in the chamber 20, for example, WF ₆ gas, Ar gas and NH ₃ gas from the gas supply sources 50 and 60 are supplied to the shower head 10 through the respective pipes 51 and 61 and the like. First and second gas inlets 11 and 12
Etc. individually. The WF ₆ gas, the Ar gas, and the NH ₃ gas pass through the first and second gas branch passages 11A and 12A and the middle gas passages 11B and 12B, respectively, to the lower gas passage 11.
C, 12C and through these openings the chamber 20
It is discharged in a shower shape into the inside, and is uniformly mixed for the first time in the chamber 20. In this case, WF ₆ gas, Ar gas and NH ₃ gas respectively flow rate is set to the same conditions as the case of forming a WN _X film on a semiconductor wafer W, for example. Predetermined time chamber 20 these material gases in the flow rate (e.g., 20 about several minutes) by supplying individually, WN _X film is formed on the susceptor 30 and its periphery.

[0033] In this embodiment after the pre-treatment in the chamber 20, subjected to a surface treatment on the semiconductor wafer W before forming the WN _X film. That is, as the semiconductor wafer W, for example, the gate oxide film 200 Å and the polysilicon film 50
0 angstrom layers are sequentially stacked from the lower layer. The semiconductor wafer W is carried into the chamber 20, held on the susceptor 30, and heated to a predetermined temperature. Continuing before depositing the WN _X film to the semiconductor wafer W showerhead 10 and the chamber 20 in a state of being set to a predetermined temperature, the chamber 2 the WF ₆ gas and Ar gas from the shower head 10 at a predetermined flow rate
The WF ₆ gas and polysilicon react by individually supplying the semiconductor wafer W into the inside of the chamber 20 for a predetermined time (for example, about 10 seconds) and setting the processing pressure of the semiconductor wafer W in the chamber 20 to a predetermined pressure. Surface treatment of the film is performed.

The predetermined temperature of the semiconductor wafer W is 300 to 50
The temperature is set to 0 ° C, more preferably 450 to 500 ° C. If the temperature of the semiconductor wafer W is lower than 300 ° C., the formation speed of the adhesion layer may be lower than an allowable range. If the temperature exceeds 500 ° C., the formation speed of the adhesion layer is too high. However, there is a problem that it becomes difficult, and it is not preferable because the use can be restricted. Predetermined flow rate of the WF ₆ gas is for example 0.5～10Sccm, more preferably set to 0.5～2Sccm. 5 × 10 ^-4 to 10 Torr in terms of partial pressure of WF ₆ gas
r, more preferably 5 × 10 ^{−4 to} 0.5 Torr. When the flow rate of the WF ₆ gas is less than 0.5 sccm, the reaction between the WF ₆ and the polysilicon on the surface of the semiconductor wafer W is insufficient, so that the surface cannot be activated, and the formation speed of the adhesion layer becomes slower than an allowable range. , WF ₆ there is a possibility that significance is eliminated contacting the gas formation rate is too high the adhesive layer exceeds 10 sccm, there is a possibility that control of the film thickness is difficult when it is desired in particular to obtain a thin film. Further, the predetermined processing pressure of the semiconductor wafer W is set to 0.1.
The pressure is set to 1 to 20 Torr, more preferably 0.3 to 3 Torr. If it is less than 0.1 Torr, the formation speed of the adhesion layer will be lower than the allowable range, and if it exceeds 20 Torr, the formation speed of the adhesion layer will be too high, and it may be difficult to control the film thickness particularly when it is desired to obtain a thin film.

After performing this surface treatment, a barrier film is formed.
Perform a film forming process of the WN _X film. To do that, shower head 1
0, WF ₆ gas, Ar gas and NH ₃ gas are supplied at predetermined flow rates for a predetermined time (for example, about 10 seconds) into the chamber 20, and the polycrystalline semiconductor wafer W set at a predetermined temperature on the susceptor 30. forming a WN _X film on the silicon film. Continue, forming a W film of 1000 angstroms on the WN _X film by a conventional W-CVD method. Thereafter, for example, when there is a BPSG reflow process of the interlayer insulating film, a heat load at a predetermined temperature (for example, 850 to 900 ° C.) may be applied to the semiconductor wafer W as conventionally known.

The predetermined temperature of the semiconductor wafer W is 300 to 65
The temperature is set to 0 ° C, more preferably 450 to 550 ° C. If the temperature of the semiconductor wafer W is lower than 300 ° C., the WN _X film tends to be amorphous, and the film is easily peeled off after RTN.
If the temperature exceeds 50 ° C., for example, when the film is used as a barrier film for Cu wiring, there is a problem that the temperature exceeds a heat-resistant temperature depending on an interlayer insulating film, and the use is restricted, which is not preferable. WF ₆
The predetermined flow rate of the gas is set to, for example, 0.5 to 100 sccm, more preferably, 1 to 50 sccm. The flow rate of WF ₆ gas is 0.
Is less than 5sccm there is a possibility that the deposition rate is slower than the allowable range, there is a possibility that WN _X film exceeds 100sccm is liable occur delamination after liable RTN become amorphous. The predetermined flow rate of the NH ₃ gas is set, for example, to 20 to 1000 sccm, more preferably 150 to 500 sccm. NH ₃ flow rate of the gas becomes WN _X film amorphous is less than 20sccm liable RT
There is a possibility that the film peeling after N may easily occur, and if it exceeds 1000 sccm, the partial pressure of the WF ₆ gas may decrease and the film forming speed may fall below an allowable range. The predetermined flow rate of the Ar gas is, for example, 10 to 30.
00 sccm, more preferably 50 to 2000 sccm. If the flow rate of the Ar gas is less than 10 sccm, the WF ₆ gas diffuses into the NH ₃ gas supply line, or the NH ₃ gas diffuses into the WF ₆ gas supply line. , there is a possibility that the piping is clogged with particles, deposition rate decreases the partial pressure of WF ₆ gas exceeds 3000sccm there is a risk below the tolerance. The processing pressure of the semiconductor wafer W in the film forming process of the WN _X film 0.1
５０50 Torr, more preferably 0.3 to 3 Torr. Slower than the deposition rate tolerance of WN _X film is less than 0.1 Torr, exceeds 50Torr too deposition rate fast, especially when it is desired to obtain a thin film is sometimes control of film thickness is difficult.

[0037]

Next, specific embodiments will be described. Example 1 In this example, performs a pretreatment chamber under the following conditions, was precoated with WN _X film susceptor and its vicinity.
To understand the thickness of pre-coating film, while placing the semiconductor wafer on the susceptor in the chamber, thereby forming a WN _X film on a semiconductor wafer surface in the pre-treatment under the same conditions. When the semiconductor wafer is mounted on the susceptor under these conditions, the surface temperature of the semiconductor wafer corresponds to a temperature 56 ° C. lower than the susceptor. The thickness of WN _X film formed on the susceptor and its vicinity becomes more the thickness of the WN _X film formed on a semiconductor wafer at least the same conditions. As a result of measuring the film thickness of the WN _X film formed on a semiconductor wafer, the film thickness was about 1.5 [mu] m. Therefore, it is considered that the thickness of the precoat film is at least about 1.5 μm or more. [Conditions of pretreatment] (1) Conditions of semiconductor manufacturing equipment Pressure in chamber: 0.3 Torr Temperature of inner wall surface of chamber: 170 ° C Shower head temperature: 170 ° C Susceptor temperature: 506 ° C (2) During pretreatment Source gas conditions for the first step Source gas flow rate: WF ₆ / NH ₃ / Ar / N ₂ = 2/50/100/100 (sccm) Processing time: 60 seconds Second step Source gas flow rate: WF ₆ / NH ₃ / Ar / N ₂ = 10/50/100/100 (sccm) Processing time: 1360 seconds The preprocessing conditions may be set as follows. (1) 'Conditions of semiconductor manufacturing equipment Pressure in chamber: 1 Torr Temperature of inner wall surface of chamber: 130 ° C Shower head temperature: 150 ° C Susceptor temperature: 506 ° C (2)' Conditions of raw material gas at pretreatment No. One-step pressure: 1 Torr Source gas flow rate: WF ₆ / NH ₃ / Ar / N ₂ = 1/500/500/500 (sccm) Processing time: 120 seconds Second step pressure: 1 Torr Source gas flow rate: WF ₆ / NH ₃ / Ar / N ₂ = 50/500/500/500 (sccm) Processing time: 720 seconds

After performing the above pretreatment, a polysilicon film (500 Å) / gate oxide film (2
After placing the semiconductor wafer on which the respective films (00 angstrom) were formed on the susceptor in the chamber, the surface treatment of the polysilicon film of the semiconductor wafer was performed using WF ₆ gas under the following conditions. thereby forming a WN _X film in the polysilicon film by performing a film forming process. [Surface treatment] (1) Conditions for semiconductor manufacturing equipment Pressure in chamber: 0.3 Torr Temperature of inner wall surface of chamber: 170 ° C Shower head temperature: 170 ° C Susceptor temperature: 506 ° C Surface temperature of semiconductor wafer: 450 ° C (2) Flow rate of source gas: WF ₆ / NH ₃ / Ar / N ₂ = 1.3 / 0/100/100 (sc
(cm) Treatment time: 10 seconds [Film formation treatment] (1) Conditions for semiconductor manufacturing equipment: Same conditions as surface treatment (2) Source gas flow rate: WF ₆ / NH ₃ / Ar / N ₂ = 2/50/100 / 100 (sccm) Processing time: 10 seconds

[0039] After the above-mentioned film forming process, was measured by the four-probe method the sheet resistance of the WN _X film, 185 ohm / s
q. From the SEM observation, the film thickness including the underlayer was 2
Since it was 50 Å, the specific resistance was 462 μm.
Ωcm.

[0040] Then, to form a 1000 Å tungsten (W) film on WN _X film by performing a film forming process by a conventional W-CVD method. The sheet resistance of this time the W / WN _X film was measured by four-probe method, a low sheet resistance value of 1.314 ohms / sq was obtained. Furthermore, in order to know the presence or absence of film separation was subjected to a heat resistance test of W / WN _X film. That is, a thermal load is applied to the W / WN _X film of the semiconductor wafer at 900 ° C. for 600 seconds (rapid thermal anneal).
al: RTA) was performed. Barrier properties were determined from the presence or absence of an increase in sheet resistance after RTA and SIMS analysis.
The adhesion was evaluated from the presence or absence of later film peeling. R
If it is destroyed barrier of WN _X film by TN, Si atoms W
Diffuses into the film, resulting in increased sheet resistance and SIMS
In the analysis, diffusion of Si atoms into the W film or diffusion of W atoms into the polysilicon film should be observed. Also, W / WN
If the adhesion at any interface of the _X / polysilicon film is not sufficient, RTA will cause film peeling. However, as a result of evaluating the semiconductor wafer obtained in this example as described above, the sheet resistance after RTA was 1.
The sheet resistance was 111 Ω / sq, and the sheet resistance was low. Diffusion of W atoms into the polysilicon film and peeling of the film by the backside SIMS were not observed. It is considered that the reason why the sheet resistance was lowered was that there was no diffusion into Si atoms, and that the tungsten crystal grains had a large grain size.

As described above, according to the present embodiment, the W / WN _X / polysilicon film has no problem in the barrier properties and adhesion, and the heat treatment increases the crystal structure of tungsten in the W film. and further reducing the resistance of Te, W / WN _X / polysilicon film when subjected to a surface treatment was found to be a very good film structure as the gate electrode structure. Further, WF ₆ gas and the resistance of the reaction layer of the polysilicon film is low, when the WN _X film formed on the polysilicon film is less thin 500 Å, the reaction layer contributes as a path of current,
The specific resistance of the apparent WN _X film was found to be lower. In case of extreme, 1/1 of the case where WF ₆ gas is not contacted before film formation
In some cases, the surface treatment of contacting WF ₆ gas before film formation is suitable for lowering the resistance of the entire gate.

Then, after a predetermined number of semiconductor wafers are formed under the above conditions, the temperature of the susceptor is raised to 300 ° C.
℃, the temperature of the inner wall of the chamber and the showerhead
Hold at 00 ° C. and simultaneously supply ClF ₃ gas and Ar gas as cleaning gas into the chamber under the following conditions,
Cleaning was carried out in the chamber in F ₃ gas. After cleaning, heating of the susceptor, the chamber and the shower head was stopped, and after returning to room temperature, the chamber was opened and the inside was visually observed.As a result, all of the susceptor, the chamber and the shower head were as clean as before the film formation. The surface was observed, and it was found that the inside of the chamber was sufficiently cleaned with the cleaning gas. [Cleaning conditions] (1) Pressure in chamber: 1 Torr (2) Flow rate of cleaning gas: ClF ₃ / Ar = 500/50 (sccm) (3) Cleaning time: 600 seconds

The cleaning conditions may be set as follows. (1) Pressure in chamber: 3 Torr (2) Flow rate of cleaning gas: ClF ₃ / Ar = 300/50 (sccm) (3) Cleaning time: 900 seconds

Embodiment 2 In this embodiment, a semiconductor wafer on which a polysilicon film is formed in advance is subjected to a film forming process under the same conditions as in Embodiment 1.
W / WN _X / polysilicon film was formed. Further, the surface treatment and the film forming process under the same conditions as in Example 1 continuously, the WN _X film is formed on the W film was formed WN _X / W / WN _X / polysilicon film. Thereafter, 850 ° C. in an annealing furnace, as a result of heat-treated at 60 minutes to the semiconductor wafer, it was found that oxidation resistance is remarkably increased by forming a WN _X film on the W film. That is, when the furnace temperature is 500 ° C, WN
No _{X film, WN X / W / WN X} / polysilicon film oxide of W film occurs _{but, WN X / W / WN X} / polysilicon film of this example WN _X
It was found that the film could serve as a protective film to prevent oxidation of the W film. Therefore, according to the present embodiment, the oxidation resistance of the gate electrode can be increased by using the WN _X film as a protective film of the W film. Management can be simplified and the efficiency of the heat treatment process can be increased.

Embodiment 3 In this embodiment, as shown in Table 1 below, the temperature of the susceptor was set to 456 ° C. and the temperature of the semiconductor wafer was set to 400 ° C., except that the temperature of the susceptor was set to 400 ° C. the WN _X film and the W film is formed, Table 1 as a sample NO.1
It was shown to. Then, the adhesion strength of the WN _X film to a polysilicon film was measured by a known measuring method, Table 1 and the results
It was shown to. The RTA of sample No. 1 (900 ° C., 60
Seconds) later, the presence or absence of film peeling was observed, and the results are shown in Table 1.

[0046] In Comparative Example 3-1 In this comparative example, except for omitting the surface treatment with WF ₆ form a WN _X film and the W film under the same conditions as in Example 3, this sample
This is shown in Table 1 as No. 2. Then, the same tests and observations as in Example 3 were performed, and the results are shown in Table 1.

[0047]

[Table 1]

As is clear from the results in Table 1, the sample No. 2 of Comparative Example 3-1 in which the surface treatment with WF ₆ was omitted had a W
Sample No. 1 of Example 3 with adhesion strength of / WN _X / polysilicon film
RTA is much lower than that of
It can be seen that film peeling has occurred in the later semiconductor wafer.

[0049] EXAMPLE surface treatment on the polysilicon film of a semiconductor wafer under the same conditions as in Example 3 except for using 20 seconds deposition processing time WN _X film in four embodiments, the film forming process of the WN _X film After performing the film-forming process of W and W films, the presence or absence of film peeling was observed.
O.3.

[0050] In Comparative Example 4-1 In this comparative example, except for changing the film formation processing time of temperature and WN _X film of a semiconductor wafer as shown in the following Table 2 Comparative Example 3
Sequentially forming a WN _X film and the W film on the polysilicon film 1 and the same condition, then after the same heat treatment as in Comparative Example 3-1, to observe the presence or absence of film peeling, Table 2 these results Sample
No. 4 to Sample No. 7 are shown.

[0051]

[Table 2]

As is clear from the results shown in Table 2, film peeling occurred in Samples No. 4 to No. 7 of Comparative Example 4-1 in which the surface treatment with WF ₆ was omitted. NO.3
No film peeling was observed.

[0053] Example 5 In this example, to validate low-containing fluorine concentration, the conditions for forming the poly-metal gate electrode WN _X layer, Example 5
Thereby forming a WN _X film under different conditions as in 1 to Example 5-4.

Embodiment 5-1 In this embodiment, a semiconductor wafer having a gate oxide film (50 angstroms) and a polysilicon film (500 angstroms) sequentially formed on a surface is placed on a susceptor in a chamber. , a film forming process to form an approximately 200 angstrom film thickness of the WN _X film on the polysilicon film by performing the following conditions. SIMS the amount of fluorine contained in the WN _X film
As a result of analysis in the depth direction, a value as low as 2.0 × 10 ¹⁹ atoms / cm ³ was obtained near the center of the thickness with little influence of the interface. The measurement of the concentration of the samples in the following Examples and Comparative Examples was also performed near the center of the thickness in the same manner as in the present Example. [Film formation process] (1) Conditions for semiconductor manufacturing equipment Pressure in chamber: 3 Torr Surface temperature of semiconductor wafer: 600 ° C. (2) Flow rate of source gas: WF ₆ / NH ₃ / Ar / N ₂ = 0.5 / 500 / 2000/200
0 (sccm) Concentration of WF ₆ gas: 0.01 vol% However, Ar gas and N ₂ gas were used as carrier gas of WF ₆ gas line and NH ₃ gas line, respectively.

[0055] In Example 5-2 In this example, Example 5-1 and forming a 100 Å film thickness of the WN _X film on the polysilicon film under the same conditions, subsequently forming a 1000 Å W film A laminated film having a polymetal gate structure was formed. The sheet resistance immediately after film formation (as deposition, abbreviated as asdepo) is
1.34 ohm / sq. N _{2 at} 900 ° C. for 600 seconds.
By performing the RTA in the gas atmosphere, the sheet resistance further decreased to 1.03 ohm / sq. In each case, the low resistance required for the gate electrode was sufficiently satisfied. The adhesion after the RTA, also barrier properties, results of evaluation in the same manner as in Example 1, not inferior WN _X film as compared with the case of Example 1 were obtained.

Embodiment 5-3 This embodiment is different from the embodiment 5-1 in that the WF _{6 in the} film forming process is different from that of the embodiment 5-1.
Where the flow rate is set to a smaller to 0.1 sccm, the fluorine concentration of the WN _X film obtained is 1.8 × 10 ¹⁹ atoms / cm
^{It was 3} and lower. The concentration of WF ₆ at the time of film formation was 0.0
02 vol.%.

Embodiment 5-4 In this embodiment, the temperature of the semiconductor wafer during the film forming process is set to be 650 ° C. higher than that in Embodiment 5-1.
Fluorine concentration of the resulting WN _X film, 1.5 × 10 ¹⁹ atoms /
cm ³ . The concentration of WF ₆ during the film formation was 0.01 vol.%.

Comparative Example 5-1 In this comparative example, the temperature of the semiconductor wafer during the film forming process was set lower than that of Example 5-1 at 450 ° C.
Fluorine concentration of the resulting WN _X film 8.0 × 10 ²⁰ atoms / c
m ^3, which was higher by one digit or more than that of Example 5-1.

Comparative Example 5-2 In this comparative example, the Ar / N ratio during the film forming process was different from that of Example 5-1.
_When the flow rate of both was reduced to 100 sccm, when only Ar, which is the carrier of the WF ₆ line, was reduced to 100 sccm, and when only the N ₂ gas, which was the carrier of the NH ₃ line, was reduced to 100 sccm, the flow was increased to 100 sccm. If, the fluorine concentration of the WN _X film obtained in each case in turn, 3.7 × 10 ¹⁹ ato
ms / cm ³ , 2.8 × 10 ¹⁹ atoms / cm ³ , 3.4 × 10
¹⁹ atoms / cm ³ , which was higher than that in Example 5-1.
Concentration of WF ₆ at the time of film formation was 0.02~0.07vol.%.

Comparative Example 5-3 In this comparative example, the WF ₆ during the film forming process was different from that of Example 5-1.
Was increased to 2 sccm and the obtained WN
The fluorine concentration of the _X film was 3.0 × 10 ¹⁹ atoms / cm ³ , which was higher than that of Example 5-1. Concentration of WF ₆ at the time of film formation was 0.04vol.%.

[0061] In Comparative Example 5-4 In this comparative example, was set to 0.3Torr by lowering the pressure in the film forming process with respect to Examples 5-1, the obtained WN _X
The fluorine concentration of the film was 1.1 × 10 ²⁰ atoms / cm ³ , which was higher than that in Example 5-1.

[0062] to obtain a more low WN _X film having a fluorine concentration of verification by the Examples and Comparative Examples, the preferred deposition conditions are a temperature of 600 to 650 ° C., it was found that a pressure of about 3 Torr. If this condition, a low fluorine concentration WN _X film is obtained in a wide range with respect to the concentration of WF ₆ at the time of film formation.
The flow ratio of WF ₆ to all gases is 0.002 to 0.5.
A range of 0.7 vol.% Is considered appropriate,
It was found to be in the range of 002 to 0.01 vol.%.

[0063] EXAMPLE 6 In this example, has both the adhesiveness and coatability, to verify the film formation conditions of the metal layer / insulating layer / metal layer lower electrode WN _X layer of the capacitor structure, Example 6 thereby forming a WN _X film under different conditions as in 1 through example 6-4.

Example 6-1 A semiconductor wafer having a hole having a diameter of 0.25 μm and a depth of 0.7 μm formed on the surface thereof using an oxide film was placed on a susceptor in a chamber, and then the hole was formed under the following conditions. perform a film forming process so that the flat portion thickness of about 300 angstroms between the coating of the WN _X film and (coverage) to evaluate the adhesion. Also, performed in advance, after mounting the same on the susceptor in a chamber of a semiconductor wafer having the formed TiN / Ti / low resistance Si structure PVD method, a film forming process of the WN _X film of about 300 angstroms by the following conditions 9 to ₁₀ nm Ta ₂ O ₅ film as a capacitance insulating film
D method, furthermore, a PVD-TiN film is formed as an upper electrode layer, only the upper electrode layer is patterned into an electrode structure to form a capacitor structure with the back surface of the wafer, and a positive bias is applied to the upper electrode. , And a negative bias was applied to measure the capacitance of the capacitor and the amount of leakage, respectively. Evaluation of the coverage of the WN _X film using the SEM, give about 70% as a bottom coverage (Hall bottom thickness / flat portion thickness). Further, the adhesion was evaluated by a tape test after film formation and after RTA (in an N ₂ gas atmosphere at 650 ° C. for 60 seconds), and no peeling occurred in any case. Further, the oxide film equivalent effective film thickness Teff by electric measurement is 1.2 nm, and the leak current density is 1 × 10 ⁻⁸ A
± 0.7 V was obtained as a voltage that resulted in (Amperes) / cm ² . [Deposition process] (1) Conditions of semiconductor manufacturing equipment Pressure in chamber: 1 Torr Surface temperature of semiconductor wafer: 450 ° C (2) Flow rate of source gas: WF ₆ / NH ₃ / Ar / N ₂ = 20/500/500 / 500 (scc
m) Flow rate ratio of NH ₃ gas and WF ₆ gas (NH ₃ / WF ₆ ) = 25 Concentration of WF ₆ gas: 1.3 vol% However, Ar gas and N ₂ gas are WF ₆ gas line and NH ₃ gas, respectively.
Used as carrier gas for gas line.

[0065] In Example 6-2 In this example, during the deposition process with respect to Example 6-1 WF ₆
When the flow rate was increased to 50 sccm, the bottom coverage was improved to about 100% compared to the case of Example 6-1.
Became. Adhesion and electrical properties were as good as Example 6-1. At this time, the flow ratio of NH ₃ / WF ₆ was 10, and the concentration of WF ₆ during film formation was about 3.2 vol.%.

Embodiment 6-3 In this embodiment, the conditions at the time of film formation are changed as follows from the embodiment 6-1 and, as in the case of the embodiment 6-1;
A lower electrode layer by performing a 00 Angstrom film forming process of the WN _X film thickness, coverage, adhesion, evaluation of electrical characteristics was performed. Evaluation of the coverage of the WN _X film by SEM, 100% Abbreviation bottom coverage (bottom thickness /
The thickness of the flat portion was obtained. Also, after film formation and RTA (750
(In a N ₂ gas atmosphere at 60 ° C for 60 seconds), and the adhesion was evaluated by a tape test. In each case, WN _X
No peeling of the film occurred. Also, by electrical measurement,
The voltage at which the effective oxide film equivalent thickness Teff is 1.3 nm and the leak current is 1 × 10 ⁻⁸ A (ampere) / cm ² is ±
0.7 V was obtained. [Film formation process] (1) Conditions for semiconductor manufacturing equipment Pressure in chamber: 3 Torr Surface temperature of semiconductor wafer: 400 ° C. (2) Flow rate of source gas: WF ₆ / NH ₃ / Ar / N ₂ = 100/50/100 / 100 (scc
m) NH ₃ / WF ₆ = 0.5 Concentration of WF ₆ gas: 28.6 vol% However, Ar gas and N ₂ gas were used as carrier gas of WF ₆ gas line and NH ₃ gas line, respectively.

Embodiment 6-4 In this embodiment, the temperature of the wafer is set to 3 as compared with the embodiment 6-1.
The temperature was set to 00 ° C., the pressure in the chamber was set to 0.5 Torr, and the film thickness was set to about 500 Å.
The film forming process was performed in the same manner as in the above case. Then, it was evaluated coverage of the WN _X film by SEM, substantially 100%
Bottom coverage (bottom film thickness / flat portion film thickness) was obtained. Also it was evaluated in the adhesion by tape test after the film formation and after RTA (60 seconds under N ₂ gas atmosphere at 650 ° C.), the peeling of the WN _X film in each case did not occur . Further, the oxide film-equivalent effective film thickness Teff by electric measurement is 1.3 nm, and the leak current density is 1 × 10 ⁻⁸ A.
± 0.7 V was obtained as a voltage that resulted in (Amperes) / cm ² .

Comparative Example 6-1 In this comparative example, the flow rate of WF ₆ during film formation was set to 2 sccm, and the NH ₃ / WF ₆ flow rate ratio was set to 2 sccm.
Was set as large as 50, the bottom coverage of the WN _X film was reduced to approximately 15%. In this case, the concentration of WF ₆ during the film formation was 0.13vol.%.

[0069] In Comparative Example 6-2 In this comparative example, was deposited to 3000 Å thickness by increasing the WN _X film thickness for Examples 6-3, the coverage of the WN _X film carried It was comparable to that of example 6-3, but peeling of the WN _X film occurred in the tape test after the film formation. In this case, the concentration of WF ₆ at the time of film formation 28.6vol.%
It is. The NH ₃ / WF ₆ flow ratio was 0.5.

Comparative Example 6-3 In this comparative example, when the temperature of the semiconductor wafer during film formation was set higher than that of Example 6-1 and set at 600 ° C., the bottom coverage was reduced to about 20%. In this case, the concentration of WF ₆ at the time of film formation was 1.3vol.%. NH ₃ / WF ₆ flow ratio is 2
It was 5.

Comparative Example 6-4 In this comparative example, when the pressure in the chamber at the time of film formation was set higher than that in Example 6-1 to 10 Torr, the bottom coverage was reduced to about 40%. In this case,
The concentration of WF ₆ is 1.3 vol.%. NH ₃ / WF ₆ flow ratio is 25
Met.

From the above-mentioned verifications of the present example and comparative example, preferable film forming conditions from the viewpoints of coverage and adhesion are as follows.
, And the as the gas composition, flow rate ratio of about for all gases WF ₆ 1~30vol.%, Or NH ₃ / WF ₆ flow rate ratio is 0.5
-25. Further, it is preferable WN _X film thickness is less than about 500 Angstroms.

Here, the conditions for forming the lower electrode of the capacitor having excellent coverage and adhesion will be further discussed below. Therefore, it is actually 1.34 μm with 0.35 μm diameter.
After forming a film in a hole having a depth of m under some conditions, the film formation state was observed with an SEM, and the results are shown in FIG. From the figure, it was found that film formation with good coverage was achieved when the following conditions were satisfied. Low deposition temperature (compare ▲ and □ in FIG. 2) Low NH ₃ flow rate Low WF ₆ and NH ₃ flow rate ratio (NH ₃ / WF ₆ ) Low deposition pressure (0 in FIG. 2) .3 Torr, 0.5 Torr and 3
Torr) The flow rates of Ar gas and N ₂ gas are small (Ar, N ₂
= Compare 100sccm, 500sccm, 1000sccm)

Further, regarding the conditions of the above-mentioned (1), Arrhenius plots ((a) and (b) in FIG. 3 and FIG.
(A) and (b)) and a saturation curve (FIG. 5)
(A) to (c)) can be considered. Further, the adhesion can be considered by the presence or absence of peeling using a tape.

That is, the film formation characteristics can be known from the Arrhenius plot and the saturation curve. From the Arrhenius plot, it can be determined whether the film forming conditions are in the range of the source gas supply rate-determining range or the source gas reaction-limiting range. In general, it is said that the better the coating is, the better the reaction rate is. Also, shows the relationship between the raw material gas, such as WF ₆ gas and the deposition rate is from saturation curves, assuming the presence of about WF ₆ gas closer to the bottom in the hole is reduced, WF ₆ gas in the saturation curve Good coverage is obtained in a range where the film forming rate does not change even if the flow rate of the film changes.

[0076] In the present invention a method the relationship between coverage and deposition temperature, the flow rate of NH _3, the flow ratio of WF ₆ and NH ₃ (N
H ₃ / WF ₆ ), (a) and (b) of FIG. 3 and (a) of FIG.
In any of the Arrhenius plots shown in (b), it can be seen that the slope of the plot becomes smaller as the film formation temperature increases, and the supply rate is controlled. This indicates that good coating properties can be obtained in a range where the film formation temperature is low.

[0077] According to the Arrhenius plot shown in FIG. 3 (a) comparing the effect of the flow rate of NH ₃ gas relationship of the flow rate of coverage and NH ₃ gas, the inclination of the plot when the flow rate of the NH ₃ gas is increased It can be seen that it has become smaller and has shifted to supply-limiting. In other words, it can be seen that good coverage is obtained in a range where the flow rate of the NH ₃ gas is low. In addition, according to the saturation curve shown in FIG.
If a region with a small amount of ₆ gases is used, it can be seen that the lower the flow rate of the NH ₃ gas, the smaller the rate of change of the film forming rate with respect to the change of the WF ₆ gas, which is a proof that good coverage is obtained.

Covering property and flow ratio of WF ₆ to NH ₃ (NH ₃ / WF ₆ )
According to the Arrhenius plot shown in FIG. 3B in which the effect of the flow ratio NH ₃ / WF ₆ is compared, the slope of the plot becomes smaller as the flow ratio becomes larger, and the transition from lower temperature to supply rate-limiting occurs. It turns out that there is. This indicates that good coverage can be obtained in a range where the flow rate ratio is small.

Relationship between Covering Property and Pressure According to FIGS. 4A and 4B in which the influence of the film forming pressure is compared, the higher the film forming pressure, the smaller the slope of the plot, or the lower the supply rate from the lower temperature. It turns out that it shifts to. This indicates that good coverage can be obtained in a range where the film formation pressure is low. According to the saturation curve shown in FIG. 5B, the rate of change of the film forming rate with respect to the change of the WF ₆ gas is smaller as the film forming pressure is lower, especially when a region with a small amount of the WF ₆ gas is used. It can be seen that the testimony indicates good coverage.

Ar gas which is a coating gas and a carrier gas and
Regarding the relationship between the flow rates of N ₂ gas This relationship cannot be understood from the Arrhenius plot, and it is necessary to rely on the saturation curve shown in FIG. 5C.
Flow rate of the gas and N ₂ gas having the lower, throughout the curve
The rate of change of the deposition rate with respect to the change of the WF ₆ gas is small. From this, it can be seen that good coverage is exhibited in a range where the flow rates of the Ar gas and the N ₂ gas are low.

The results of a tape test for examining the adhesion of the lower electrode are shown in Tables 3 and 4 below. Table 3 shows the results after film formation, and Table 4 shows the results after annealing. Table 3
And according to the results shown in Table 4, good film formation condition of the adhesion, film-forming temperature is high, a large NH ₃ / WF ₆ ratio, NH ₃
, The film formation pressure was high, and the amount of Ar gas and N ₂ gas was large. In the column of wafer temperature in Table 3, P means that the film has peeled off, NP means that the film has not peeled off, and the numerical value means the film thickness (unit: angstrom).

[0082]

[Table 3]

[0083]

[Table 4]

Further, the reason why the adhesion is good can be explained by the crystallinity and the composition ratio (N / W) of nitrogen atoms and tungsten atoms. That is, as shown in FIG.
Half width FWHM of W2N (111) plane of the WN _X film is increased, the composition position ratio N / W of a film XPS measurement is reduced. The degree of change is greater as the deposition temperature of the WN _X film is low. Also WN _X
The lower the film formation temperature, the greater the FWHM of the as depo. From these series of facts, as the annealing mechanism, nitrogen is released from the WN _X film by annealing, and the crystallinity of the WN _X film deteriorates, and if the deterioration further progresses, it will be peeled off. It can be guessed that it is more remarkable in a film originally having poor crystallinity.

[0085] In Example 7 This example, small leakage amount, to verify the film formation conditions of the WN _X layer for the bottom electrode of the capacitor of the metal layer / insulating layer / metal layer structure, examples 7-1 thereby forming a WN _X film under different conditions as in example 7-8.

[0086] In Examples 7-1 This example, SiH in WN _X film formation for Examples 6-2
₄ gases were flowed together at a flow rate of 20 sccm, and further, as a post-flow after film formation, Ar / N ₂ / SiH ₄ = 100/100/20 sc
After flowing for 60 seconds at a flow rate ratio of cm, the coatability, adhesion, and effective oxide film thickness determined by electrical measurement were all the same as in Example 6-2, but the leakage amount was Was improved, and ± 0.9 V was obtained as a voltage at which the leakage current density became 1 × 10 ⁻⁸ A (ampere) / cm ² . Comparing the current-voltage curves (not shown; the same applies hereinafter) at the time of measuring the amount of leakage, the region where the amount of leakage does not increase even when the voltage is increased is wider than that of Example 6-2, and Ta ₂ O ₅ / WN _X It was shown that the Schottky barrier was sufficiently formed at the interface. The electric field strength also ranges from 5.38 MV / cm to 5.94 MV / cm (＠
1 × 10 ⁻⁸ A (ampere) / cm ² ).

[0087] In Example 7-2 In this example, after WN _X film formation relative to Example 6-2, N
H ₃ gas with a flow rate of 500 sccm and plasma power of 400 W
When the NH ₃ plasma (watts) irradiation for 120 seconds, was nitrided Ta ₂ 0 ₅ deposition before the WN _X surface, coverage, adhesion,
And the equivalent oxide film thickness obtained by electrical measurement was the same as that of Example 6-2, but the leakage amount was improved and the leak current density was 1 × 10 ⁻⁸ A (ampere).
± 0.9 V was obtained as a voltage to be / cm ² . Comparing the current-voltage curves at the time of measuring the amount of leakage, the region where the amount of leakage does not increase even when the voltage is increased is wider than that of Example 6-2.
It has been shown _{that 2} O ₅ / WN _X interface Schottky barrier is sufficiently formed.

[0088] In Example 7-3 This example, NH ₃ after WN _X film formation for Examples 6-2
RTN (rapid th
thermal nitridation) to increase the nitrogen concentration of the WN _X surface layer before Ta ₂ O ₅ film formation. 6-2, but the leakage amount was improved and the leakage current density was 1 × 10 ⁻⁸ A (ampere) / cm ²
± 0.9 V was obtained. Comparing the current-voltage curves at the time of measuring the leak amount, the region where the leak amount does not increase even when the voltage is increased is wider than that of Example 6-2, and Ta ₂ O ₅ / WN
It was shown that the Schottky barrier was sufficiently formed at the _X interface.

[0089] In Example 7-4 This example, WN _X film formation after 520 ° C. in an oxygen concentration of 5% N ₂ gas atmosphere for Examples 7-1, 60 seconds RT
O (rapid thermal oxidation) before Ta ₂ O ₅ film formation
Was to form a thin SiO ₂ layer on the WN _X surface, coverage, adhesion although somewhat increase seen in equivalent oxide effective film thickness equivalent to the Examples 7-1, the amount of leakage is improved, leakage ± 0.9 V was obtained as a voltage at which the current density became 1 × 10 ⁻⁸ A (ampere) / cm ² . Comparing the current-voltage curves at the time of measuring the amount of leakage, the region where the amount of leakage does not increase even when the voltage is increased is wider than that of Example 6-2, and the Schottky barrier is sufficiently formed at the Ta ₂ O ₅ / WN _X interface. It was shown that. The electric field strength is also 5.87 MV / cm (＠ 1 × 10 ^-8 A)
(Ampere) / cm ² ).

[0090] In Example 7-5 This example, NH ₃ after WN _X film formation for Examples 6-2
/ Ar / N ₂ / SiH ₄ was flowed as a post flow at a flow rate of 500/100/100 / 20sccm for 60 seconds, respectively, and the coating film, the adhesion, and the oxide film equivalent effective film obtained by electrical measurement The thickness was the same as that of Example 6-2, but the leakage amount was improved and the leakage current density was 1 × 10 ^−8.
A voltage of ± 0.9 V was obtained as A (ampere) / cm ² . Comparing the current-voltage curve during leak rate measurement, wide area even by raising the voltage does not increase the amount of leakage as compared with Examples _{6-2, Ta 2 O 5 / WN} X interface Schottky barrier is fully formed It was shown that.

[0091] In Example 7-6 This example, WF after WN _X film formation relative to Example 6-2 ₆
1/100/1 to postflow / Ar / N ₂ / SiH ₄ respectively
After flowing for 60 seconds at a flow rate of 00/20 sccm, the coatability, adhesion, and oxide film equivalent effective thickness determined by electrical measurement were all the same as in Example 6-2, The leakage amount is improved and the leakage current density is 1 × 10 ^-8
A voltage of ± 0.9 V was obtained as A (ampere) / cm ² . Comparing the current-voltage curve during leak rate measurement, wide area even by raising the voltage does not increase the amount of leakage as compared with Examples _{6-2, Ta 2 O 5 / WN} X interface Schottky barrier is fully formed It was shown that.

Example 7-7 In this example, after forming the film of Example 7-6, RTO was performed at 520 ° C. for 60 seconds in an N ₂ gas atmosphere having an oxygen concentration of 5% to form a Ta ₂ O _{5 layer.} was oxidized electrode surface of the WN _X containing film prior to Si, coverage, adhesion although equivalent oxide film equivalent effective film thickness in example 7-6 was observed rather slight increase, leakage The amount was improved, and ± 0.9 V was obtained as a voltage at which the leak current density was 1 × 10 ⁻⁸ A (ampere) / cm ² . Comparing the current-voltage curves at the time of measuring the amount of leakage,
2 wider region also does not increase the leakage amount to increase the voltage in comparison with, it was shown that Ta ₂ O ₅ / WN _X interface Schottky barrier is sufficiently formed. Electric field strength is 5.88MV /
cm (＠ 1 × 10 ⁻⁸ A (ampere) / cm ² ).

[0093] In Example 7-8 In this example, at a flow rate of NH ₃ gas after deposition for Examples 7-6 500 sccm, the NH ₃ plasma plasma power 400W (watts) irradiation for 120 seconds, Ta ₂ O ₅ before film formation
Was the WN _X surface by nitriding, coating, adhesion, and none of the oxide film equivalent effective film thickness determined by electrical measurement was equivalent to the case of Example 7-6, the amount of leakage is improved And the leak current density is 1 × 10 ⁻⁸ A (ampere) / cm ²
± 1.0 V was obtained. Comparing the current-voltage curves at the time of measuring the leak amount, the region where the leak amount does not increase even when the voltage is increased is wider than that of Example 6-2, and Ta ₂ O ₅ / WN
It was shown that the Schottky barrier was sufficiently formed at the _X interface.

[0094] From the verification by the above-described embodiment, expanding the range of voltages the leakage current density is equal to or less than a predetermined value, in order to improve a Schottky barrier, a WN _X film, for example under the conditions of Example 6-2 It has been found that the following treatment may be performed when forming the film or after forming the film. Add SiH ₄ gas during film formation, or
Performing post-flow gas containing H ₄ gas. As the gas containing SiH ₄ gas, for example, a mixed gas of SiH ₄ gas and WF ₆ gas or S
There is a mixed gas of iH ₄ and NH ₃ gas. After the film formation, or the addition of SiH ₄ gas during deposition nitriding the WN _X film surface, or after the film is formed Si
Post-flow is performed with a gas containing H ₄ gas, and then the surface is oxidized. SiH after or deposited adding SiH ₄ gas during deposition ₄
Post flow is performed with a gas containing gas, and then the surface is nitrided. From the viewpoint of particle reduction, when supplying the SiH ₄ gas and NH ₃ gas, flowing first NH ₃ gas, then SiH ₄
Let the gas flow. When stopping the supply of gas is to first stop the supply of the SiH ₄ gas, may then NH ₃ sufficiently purge the SiH ₄ gas in the gas.

[0095] Further, in order to increase the effect of satisfactorily forming a Schottky barrier, it has been found that the layered structure of repeated another layer on the WN _X layer is also effective. (1) WN _X layer of tungsten silicide (WSi) layer WSi / WN _X film overlaid on. When the surface of the WN _X covered with WSi film, nitrogen in WN _X even in a high temperature processing such as annealing after ceases escape outside film causes no reduction in volume WN _X, it does not occur membrane stress and peeling problems . Further, the film quality of this laminated film can be improved by the following processing. The surface is nitrided by annealing in NH ₃ or plasma treatment of N ₂ or NH ₃ , or the extreme surface is oxidized by annealing in an oxidizing atmosphere or plasma treatment of an oxidizing gas. The reason is that help them, processed by WN _X film surface with high forming nitrogen concentration layer or the surface oxide layer of the form a good Schottky barrier between the Ta ₂ O _5, in the heat load process after the heat resistance of the WN _X film,
This is for improving the oxidation resistance. (2) WN _X silicon nitride on the layer (SiN) layer superimposed SiN / WN _X film. When the surface of the WN _X covered with the SiN film, the nitrogen in the WN _X even in a high temperature processing such as annealing after ceases escape outside film causes no reduction in volume WN _X, it does not occur membrane stress and peeling problems . A laminated film of a WN _X film or other film having such characteristics, the top of the capacitor, it is also applicable to other wiring portions as well as the lower electrode layer.

Embodiment 8 In this embodiment, a WN _X for a capacitor having a metal layer / insulating layer / metal layer structure or an upper electrode having a metal layer / insulating layer / semiconductor layer structure is used.
To verify the film formation conditions of the layer, to form a WN _X film under different conditions as in Example 8-1 and Example 8-2.

Embodiment 8-1 In this embodiment, a Ta ₂ O ₅ film having a thickness of 100 Å is used as a capacitive insulating film, and has a diameter of 0.3 μm and a depth of 0.1 μm.
Perform a film forming process of the WN _X film to the flat portion thickness under the following conditions as the upper electrode of 6μm of the capacitor cells is approximately 200 angstroms, coverage, the evaluation of electrical characteristics and adhesion was carried out. The covering properties and the electrical properties are each SE
Evaluation was performed based on M observation, an effective oxide film equivalent film thickness, and a leak amount. In addition, the adhesion between the WN _X film and the base is WN _X
As depo state after film formation and heat treatment for heat resistance test (650 ℃
Was evaluated by a tape test after RTA for 60 seconds in an N ₂ gas atmosphere. As a result, the coverage is about 100.
% Bottom coverage (bottom film thickness / flat portion film thickness) was obtained. Regarding the adhesion, no peeling occurred in both the as depo state and the heat treatment. Further, as the electrical characteristics, the oxide film equivalent effective film thickness Teff is 1.2 nm and the leak current density is 1 ×
± 0.9 as a voltage to be 10 ⁻⁸ A (ampere) / cm ²
V was obtained. [Surface treatment] (1) Conditions for semiconductor manufacturing equipment Pressure in chamber: 1 Torr Surface temperature of semiconductor wafer: 400 ° C. (2) Flow rate of source gas: WF ₆ / NH ₃ / Ar / N ₂ = 50/0/500 / 500 (scc
m) However, Ar gas and N ₂ gas were used as carrier gases for the WF ₆ gas line and the NH ₃ gas line, respectively. Processing time: 60 seconds [Film formation processing] (1) Conditions for semiconductor manufacturing equipment: Same conditions as surface treatment (2) Source gas flow rate: WF ₆ / NH ₃ / Ar / N ₂ = 50/500/500/500 ( scc
m)

[0098] In Example 8-2 In this example, without surface treatment of the WN _X film for Examples 8-1, by changing the condition during the film formation, as follows: Example 8
After forming the WN _X film of about 200 Å as in the case of -1, coverage, adhesion was carried out electrical characterization in the same manner as in Example 8-1. As a result, a bottom coverage of about 100% was obtained as the covering property. Regarding the adhesion, no peeling occurred in both the as depo state and the heat treatment. In addition, as an electrical characteristic, the oxide film equivalent effective film thickness Teff
± 1.25 V as a voltage at which the leakage current density was 1.2 nm and the leak current density was 1 × 10 ⁻⁸ A (ampere) / cm ² . [Deposition Process] (1) Conditions of Semiconductor Manufacturing Apparatus Pressure in chamber: 1 Torr Surface temperature of semiconductor wafer: 450 ° C. (2) Source gas flow rate: First step: WF ₆ / NH ₃ / Ar / N ₂ = 0 / 500/500/500 (sccm) Processing time: 60 seconds Second step: WF ₆ / NH ₃ / Ar / N ₂ = 50/500/500/500 (scc
m) However, Ar gas and N ₂ gas were used as carrier gases for the WF ₆ gas line and NH ₃ gas line, respectively.

Comparative Example 8-1 In this comparative example, when the wafer temperature during film formation was set to 550 ° C. higher than that in Example 8-2, the adhesion was the same as in Example 8-2. However, the bottom coverage was reduced to about 30%, and the leak current density at −0.7 V was increased to 1 × 10 ⁻⁵ A / cm ² .

Comparative Example 8-2 In this comparative example, when the flow rate of NH ₃ at the time of film formation was increased to 1000 sccm with respect to Example 8-2, the adhesion was the same as in Example 8-2. However, the bottom coverage was about 60%, and the leakage current density at -0.7 V was 1%.
It increased to × 10 ⁻⁶ A / cm ² .

[0102] From the verification by the above-described Examples and Comparative Examples, when using a WN _X film as an upper electrode of the capacitor,
It is preferable that the film forming conditions satisfy the following conditions from the viewpoints of coverage, adhesion, and electrical characteristics. The temperature of the semiconductor wafer is preferably lower than 550 ° C, more preferably 400 to 450 ° C. It is preferable flow rate ratio of NH ₃ / WF ₆ is less than about 20, more preferably about 2-10. Concentration of WF ₆ to total gas is preferably about 1.0 vol. Greater than%, and more preferably about 2~20vol.%.

[0102] Further, WN _X film adhesion and electrical properties than the time of film formation was found to be improved by properly annealed at high temperatures. That is, to reduce the resistance of the WN _X film. WN _X film quality of stabilized, hardly occurs even variations and peeling at a high temperature step after. To further reduce the fluorine concentration of the WN _X film. For the resistance reduction in the thickness of the WN _X film of about 700 angstroms, immediately after the film formation is specific resistance 40
After annealing in an N ₂ gas atmosphere at 650 ° C. for 60 seconds, the specific resistance was 170 μΩcm.
0 μΩcm, and in an N ₂ gas atmosphere at 900 ° C.
After annealing for 0 seconds, it decreased to 15 μΩcm. For stabilization, isolated nitrogen atoms removed from the WN _X by annealing, to a certain extent since the deformation is inevitable that an object be mitigated by pre-heat treatment of the damage of the deformation in the high temperature process. For example,
A) heat treatment at a temperature of 80% or less before the high temperature process; b) heat treatment at a time of 50% or less before the long time high temperature process; c) lamination of a film with a large stress such as tungsten. Is to heat-treat at the same temperature as the high-temperature process after forming tungsten or the like with a WN _X single film before laminating tungsten or the like. D) When laminating a highly brittle film such as Ta ₂ O ₅ film, Ta ₂ O ₅ in WN _X unilamellar before laminating ₂ O ₅ film, etc.
The film quality is stabilized by performing a heat treatment at the same temperature as the high temperature process after forming the film or the like at a temperature about 50 ° C. higher than the same temperature so as not to deform during the actual high temperature process. be able to.

In the case where WN _X is formed as the upper electrode of the capacitor or a part thereof, as in the case of application to the lower electrode in the seventh embodiment, when the WN _X film is formed or after the formation, It was found that a better film could be obtained by the treatment. Add silane (SiH ₄ ) gas during film formation or after film formation
Post flow is performed using a gas containing SiH ₄ gas. After the film formation, nitriding the WN _X film surface. SiH after or deposited adding SiH ₄ gas during deposition ₄
Post flow with gas containing gas, and then
Oxidizes the surface. SiH after or deposited adding SiH ₄ gas during deposition ₄
Post flow is performed with a gas containing gas, and then the surface is nitrided. In the present embodiment, silane (SiH ₄ ) was used as the gas containing silicon atoms. However, disilane (Si
₂ H _6), it may also be used, such as dichlorosilane (SiH ₂ Cl _2).

[0104] In Example 9 This example, in order to verify the conditions for forming the WN _X film layer serving as a copper diffusion barrier, WN _X under different conditions as in Example 9-1 to Example 9-4 A film was formed.

Example 9-1 A semiconductor wafer having a hole shape having a diameter of 0.25 μm and a depth of 2 μm formed on the surface thereof using an oxide film was placed on a susceptor in a chamber, and then a flat portion film was formed under the following conditions. Is about 200
Å become so perform a film forming process of the WN _X film was evaluated coverage performing sectional SEM observation. Also,
After placing a semiconductor wafer on which a plasma TEOS film is formed as an interlayer insulating film on a susceptor in a chamber, under the following conditions, WN _X is adjusted to a thickness of about 200 angstroms.
A film is formed, and then CVD-Cu (about 10 mm thick) is formed.
00 Å) after the film forming process and then subjected to a tape test was to evaluate the adhesion between Cu / WN _X. Furthermore, after placing the silicon wafer which is not oxidized surface on a susceptor in the chamber, it performs a film forming process of the WN _X film so that the film thickness under the following conditions becomes about 200 angstroms, then C
After the film forming process VD-Cu (thickness: about 1000 Å), 600 ° C., 60 min, an annealing under N ₂ gas atmosphere, SEM the presence of Si pits and reactant WN _X / Si interface from measurements of SIMS profiles of observation and Cu, were evaluated barrier of WN _X. As a result, a bottom coverage (bottom film thickness / flat portion film thickness) of approximately 80% was obtained as the covering property. Regarding adhesion, there is no occurrence of film peeling,
Sufficient adhesion was obtained. No pits were observed in the barrier property, and no diffusion of Cu into silicon was observed from the SIMS profile of Cu from the back surface of the wafer, and sufficient barrier property was obtained. [Film formation process] (1) Conditions for semiconductor manufacturing equipment Pressure in chamber: 3 Torr Wafer temperature: 450 ° C. (2) Flow rate of source gas: First step: WF ₆ / NH ₃ / SiH ₄ / Ar / N ₂ = 2/200/5/100/10
0 (sccm) Second step: SiH ₄ / Ar / N ₂ = 5/100/100 (sccm) (post flow) Processing time: 60 seconds However, Ar and N ₂ are carriers of WF ₆ line and NH ₃ line, respectively. Used as gas.

[0106] In Example 9-2 In this example, the conditions during formation of the WN _X film modified as follows for Examples 9-1, Example 9-1 Similarly, coverage, adhesion Properties and barrier properties were evaluated. As a result, a bottom coverage of about 80% was obtained as the covering property. Regarding the adhesion, no peeling occurred, and sufficient adhesion was obtained. No pits were observed for the barrier properties, and the Cu SIMS profile
No diffusion was observed, and sufficient barrier properties were obtained. [Film formation process] (1) Conditions for semiconductor manufacturing equipment Pressure in chamber: 3 Torr Wafer temperature: 450 ° C. (2) Flow rate of source gas: First step: WF ₆ / NH ₃ / SiH ₄ / Ar / N ₂ = 2/200/5/100/10
0 (sccm) Film thickness: about 200 angstroms Second step (post flow): NH ₃ / Ar / N ₂ = 200/100
/ 100 (sccm) Processing time: 60 seconds However, Ar and N ₂ were used as carrier gas for WF ₆ line and NH ₃ line, respectively.

Embodiment 9-3 In this embodiment, WN is different from that of Embodiment 9-1._XAt the time of film formation
First and second steps of SiH _FourChange both the flow rate to 1sccm,
Covering properties, adhesion properties, and barrier properties as in Example 9-1
Was evaluated, the coverage, adhesion, and barrier properties
It was equivalent to Example 9-1.

[0108] In Example 9-4 In this example, the conditions during formation of the WN _X film for Examples 9-1 was changed as follows, as in the case coverage of Examples 9-1 , Adhesion and barrier properties were evaluated. As a result, a bottom coverage of about 70% was obtained as the covering property.
Adhesion and barrier properties are the same as in Example 9-1, and
The thickness of the WN _X layer was 320 Å, and the specific resistance was 550 μohm / cm (micro ohm centimeter). This specific resistance is about one digit lower than that of Example 9-1. It is considered that the tungsten-rich layer formed in the second step contributes to this low resistivity. [Film formation process] (1) Conditions of semiconductor manufacturing apparatus Pressure in chamber: 3 Torr Wafer temperature: 450 ° C. (2) Source gas flow rate: First step: WF ₆ / NH ₃ / Ar / N ₂ / H ₂ / SiH ₄ = 1/500/2000 /
2000/0/0 (sccm) Processing time: 15 seconds Second step: WF ₆ / NH ₃ / Ar / N ₂ / H ₂ / SiH ₄ = 15/0/200/0 /
400/4 (sccm) Processing time: 30 seconds Third step (post flow): SiH ₄ / Ar / N ₂ = 4/200 /
200 (sccm) Processing time: 60 seconds

Comparative Example 9-1 In this comparative example, the WN after film formation was different from that of Example 9-1._XMembrane
After performing the film-forming process of Cu-CVD after exposure to air
Other than that, the same processing as in the case of the embodiment 9-1 is performed. _XMembrane
Evaluation of covering property, adhesion property, and barrier property in the case of Example 9-1
The same was done. As a result, the coverage is the same, but the adhesion is
Occurred in tape test in as depo condition in evaluation of
However, it was found that it was not possible to proceed to the subsequent heat treatment step.

[0110] In Comparative Example 9-2 In this comparative example, to set the flow rate of SiH ₄ in a first step at the time WN _X film forming process for Examples 9-1 to 0 sccm, the in the film
No SiH ₄ added, only during the second step post flow
Except plus H ₄ performs the same processing as in Example 9-1 was carried out coverage of the WN _X film, adhesion, evaluation of barrier property in the same manner as in Example 9-1. As a result, although the coatability was the same, peeling occurred in the tape test in the as depo state in the evaluation of adhesion, and pits were observed in the evaluation of barrier properties. It turned out that it was below.

Comparative Example 9-3 In this comparative example, the WN_XAt the time of film formation
First and second steps of SiH _FourWas changed to 10 sccm
Except for the above, the same processing as in the case of the embodiment 9-1 is performed._Xfilm
Was evaluated for covering properties, adhesion properties and barrier properties. The result
As a result, the coatability and adhesion were the same as in Example 9-1.
However, in terms of barrier properties, WN_XMembrane breakage and reactant production
Formation was observed.

[0112] In Comparative Example 9-4 In this comparative example, except for changing the pressure in the chamber during the deposition of the WN _X film for Examples 9-1 to 0.3Torr as in Example 9-1 the same process, the coating of the WN _X film, adhesion, evaluation of barrier property was performed. As a result, coverage and as
While adhesion depo was comparable to that of Example 9-1, the generation of broken and the reaction product of WN _X film in barrier property evaluation was observed, was seen adhesiveness deterioration after the heat treatment.

[0113] In Comparative Example 9-5 In this comparative example, by forming a WN _X film was changed to conditions that: at the time of film formation of the WN _X film for Examples 9-1, Example 9
As in the case of No. 1, evaluation of covering property, adhesion property and barrier property was performed. As a result, a bottom coverage (bottom film thickness / flat portion film thickness) of about 40% was obtained as the covering property. The adhesion in the as depo state was equivalent to that of Example 9-1. However, in the adhesion and barrier properties, heat treatment for evaluation caused aggregation of Cu, and subsequent evaluation could not be performed. [Deposition Process] (1) Conditions of Semiconductor Manufacturing Apparatus Pressure in chamber: 3 Torr Wafer temperature: 400 ° C. (2) Source gas flow rate: First step: WF ₆ / NH ₃ / SiH ₄ / Ar / N ₂ = 1/500/5/500/50
0 (sccm) Film thickness: about 200 angstroms Second step (post flow): SiH ₄ / Ar / N ₂ = 5/500 /
500 (sccm) Processing time: 60 seconds

[0114] In Comparative Example 9-6 In this comparative example, by changing the condition at the time of film formation as follows forming a WN _X film for Examples 9-1, in the case of Example 9-1 In the same manner, evaluation of covering property, adhesion property and barrier property was performed. As a result, when the WN _X film obtained in this Comparative Example was obtained 100% bottom coverage as coverage (bottom thickness / flat portion thickness). The adhesion in the as depo state was determined in Example 9-
1 was the same, the generation of broken and the reaction product of WN _X film in the evaluation of barrier properties was observed, was seen adhesiveness deterioration after the heat treatment. (1) Conditions for semiconductor manufacturing equipment Pressure in chamber: 3 Torr Wafer temperature: 450 ° C. (2) Source gas flow rate: First step: WF ₆ / NH ₃ / SiH ₄ / Ar / N ₂ = 80/200/1 / 100/1
00 (sccm) Film thickness: about 200 angstroms Second step (post flow): SiH ₄ / Ar / N ₂ = 1/100 /
100 (sccm) Processing time: 60 seconds However, Ar gas and N ₂ gas were used as carrier gas of WF ₆ gas line and NH ₃ gas line, respectively.

[0115] In Comparative Example 9-7 In this comparative example, by changing the condition at the time of film formation as follows forming a WN _X film for Examples 9-1, in the case of Example 9-1 Similarly, evaluation of adhesion and barrier properties was performed. as a result,
When the WN _X film obtained in this Comparative Example, 5 as coverage
7% bottom coverage was obtained. The adhesion in the as depo state was equivalent to that of Example 9-1. However, heat treatment for evaluation of adhesion and barrier properties caused aggregation of Cu, and subsequent evaluation could not be performed. (1) Conditions of semiconductor manufacturing equipment Pressure in chamber: 0.5 Torr Wafer temperature: 450 ° C. (2) Source gas flow rate: First step: WF ₆ / NH ₃ / SiH ₄ / Ar / N ₂ = 1/500 / 5/500/50
0 (sccm) Film thickness: about 200 angstroms Second step (post flow): SiH ₄ / Ar / N ₂ = 5/500 /
500 (sccm) Processing time: 60 seconds However, Ar gas and N ₂ gas were used as carrier gas for WF ₆ gas line and NH ₃ gas line, respectively.

From the above verification by the present embodiment and the comparative example, WN was used as a barrier layer between the copper layer and another metal or semiconductor.
_{When the X} film was used, the following treatment was found to be effective from the viewpoints of coverage, adhesion, and electrical characteristics. In the film forming step, a gas containing silicon atoms (for example, SiH ₄ ) is added. Alternatively, post-flow treatment in which the surface is exposed to a gas containing silicon atoms (for example, SiH ₄ ) after the film formation step is performed. Also, the following was found as the preferred conditions for forming the WN _X film. The temperature is above about 300 ° C., preferably about 350-4
It must be 50 ° C. The pressure is higher than about 0.3 Torr, preferably about 1-3
Torr.

[0117] Further, the present inventors have the type of base to form the WN _X film, and obtained the following knowledge for the preferred conditions of the surface treatment prior to deposition. Here, it comprises WF _6, mode A mode for processing a gas containing no NH _3, free of WF _6, will be called a mode for processing a gas containing NH ₃ and B-mode. Surface treatment conditions With respect to various types of base films including polysilicon, tungsten, copper, SiO ₂ and Ta ₂ O ₅ , it was found that both modes A and B were effective from the viewpoint of improving adhesion. . In addition, as an application example in which the base is made of polysilicon, it is typical that the gate electrode of the transistor is a polymetal gate having a W / WN _X / poly structure. Therefore, it is necessary to extremely reduce the fluorine concentration in the film. In such a case, the B mode is more preferable as the surface treatment condition. However, in the case where it is necessary to form a film at a low temperature of 500 ° C. or less even when the underlying layer is made of polysilicon, and if it is desired to obtain adhesiveness which does not peel off even in a subsequent heating step, the A mode is desirable as a surface treatment condition. Adhesion WN _X film to polysilicon W
Although the surface treatment when the deposition temperature of the N _X is high no problem in the B-mode, withstand subsequent heat treatment Failure to advance an adhesion layer on the surface treatment of the A mode when the deposition temperature of the WN _X is low Absent. When the underlayer is a SiO ₂ film, the B mode is more preferable. The reason, adhesion is further improved, smoothness of the deposited WN _X film also because higher. As a surface treatment when forming a film on a Ta ₂ O ₅ film as a dielectric film of a capacitor, A mode is more preferable. The reason is
This is because the leak current becomes smaller.

The present invention is not limited to the above embodiments. For example, the surface treatment conditions (temperature, pressure, gas flow ratio, etc.) during and / or before and after film formation may be reduced. Optimal conditions can be appropriately set according to the application site of the tungsten film.

[0119]

According to the first to twelfth aspects of the present invention, adhesion to a base, covering properties, electrical characteristics,
It is possible to provide a semiconductor device manufacturing method and a semiconductor manufacturing apparatus capable of forming a tungsten nitride film optimal in various application portions of a semiconductor device from the viewpoint of barrier properties and the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a semiconductor manufacturing apparatus of the present invention suitably used in a method of manufacturing a semiconductor device of the present invention.

FIG. 2 is a graph showing the relationship between the NH ₃ / WF ₆ flow ratio and the bottom coverage at the bottom of a hole having a diameter of 0.35 μm and a depth of 1.34 μm.

[Figure 3] a graph showing Arrhenius plots of the time of forming the WN _X, (a) is a graph WATCHING influence of the flow rate of NH _3,
(B) is a graph showing the effect of the NH ₃ / WF ₆ flow ratio.

[Figure 4] graphically Arrhenius plot in forming a _{WN X, (a), (} b) is a graph WATCHING effect of pressure during film formation.

[5] a graph showing the saturation curve for forming the WN _X, (a) Graph WATCHING influence of the flow rate of NH ₃ is, (b) graph WATCHING effect of pressure during film formation, (c)
Is a graph showing the effect of the flow rate of the carrier gas (Ar, N ₂ ).

[6] a graph showing the WN _X film crystallinity and the composition ratio of the nitrogen atoms and tungsten atoms (N / W), (a ) is a graph showing the crystallinity of the relationship between the film forming temperature, (b 4) is a graph showing the relationship between the film forming temperature and the composition ratio (N / W).

[Explanation of symbols]

 Reference Signs List 10 shower head (gas supply mechanism) 11 first gas inlet (first inlet) 11C first lower gas passage (first outlet) 12 second gas inlet (second inlet) 12C second lower gas Flow path (second outflow port) 20 Chamber (film formation chamber) 30 Susceptor (holding body) 40 Exhaust pipe (exhaust section) 91 Valve (pressure adjusting mechanism)

Continued on the front page (72) Inventor Susumu Arima 2381-1, Kita-Shimojo, Fujii-machi, Nirasaki, Yamanashi Prefecture Inside Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Yumiko Kono 1-231, 2381 Kita-Shimojo, Fujii-machi, Nirasaki, Yamanashi Prefecture Tokyo Electron Inside Yamanashi Co., Ltd. (72) Inventor Mitsuhiro Tachibana One at 2381 Kita Shimojo, Fujii-machi, Nirasaki City, Yamanashi Prefecture Inside Tokyo Electron Co., Ltd. (72) Inventor Keizo Hosoda One at 2381 Kita Shimojo, Fujii-machi, Nirasaki City, Yamanashi Prefecture Tokyo Electron Yamanashi Co., Ltd.

Claims (12)

[Claims] 1. A method for manufacturing a semiconductor device by forming a tungsten nitride film on an object to be processed using a first source gas containing tungsten atoms and a second source gas containing nitrogen atoms, wherein the formation of the tungsten nitride film is performed. A method for manufacturing a semiconductor device, comprising: bringing a first source gas into contact with the object to be processed before. 2. As a condition for bringing a first raw material gas into contact with the object before film formation, the processing pressure of the object is set to 0.1 to 1.0.
The processing temperature of the object to be processed is set to 300 to 500 ° C., the flow rate of the first source gas is set to 0.5 to 10 sccm, or the partial pressure of the first source gas is set to 5 to 20 Torr.
2. The method for manufacturing a semiconductor device according to claim 1, wherein the pressure is set at ^10-4 to 10 Torr. 3. The conditions for forming the tungsten nitride film using the first source gas and the second source gas include setting a processing pressure of the object to be processed to 0.1 to 50 Torr and a temperature of the object to be processed. Is set to 300 to 650 ° C., and
The flow rate of the first source gas is 0.5 to 100 sccm, or
3. The method of manufacturing a semiconductor device according to claim 1, wherein the partial pressure of the source gas is set to 5 × 10 ^{−4 to} 50 Torr and the flow rate of the second source gas is set to 20 to 1000 sccm. . 4. The semiconductor device according to claim 1, wherein tungsten hexafluoride is used as the first source gas and ammonia gas is used as the second source gas. Method. 5. A gas supply mechanism for supplying a raw material gas, a film forming chamber connected to the gas supply mechanism, and a temperature-adjustable holding unit disposed in the film forming chamber and holding the object to be processed. A first source gas containing tungsten atoms and a second source gas containing nitrogen atoms as the source gas. In the film formation chamber to form a tungsten nitride film on the object to be processed in the film formation chamber, the gas supply mechanism includes first and second inlets into which first and second source gases respectively flow. , The first and the second source gases respectively communicating with the first and the second inlets, and the first and the second source gases are individually discharged.
And a pressure adjusting mechanism for adjusting a pressure in the film forming chamber is provided in the film forming chamber or the exhaust unit. 6. A method for manufacturing a semiconductor device by forming a tungsten nitride film on an object to be processed using a first source gas containing tungsten atoms and a second source gas containing nitrogen atoms. First, second before forming
A method for manufacturing a semiconductor device, comprising: bringing a gas containing any one of source gases into contact with the surface of an object to be processed. 7. A method for manufacturing a semiconductor device by forming a tungsten nitride film on an object to be processed using a first source gas containing tungsten atoms and a second source gas containing nitrogen atoms. A method for manufacturing a semiconductor device, comprising forming a tungsten nitride film by adding a gas containing silicon atoms during formation. 8. A method for manufacturing a semiconductor device by forming a tungsten nitride film on an object to be processed using a first source gas containing tungsten atoms and a second source gas containing nitrogen atoms. A method for manufacturing a semiconductor device, comprising contacting a gas containing a gas containing silicon atoms with the tungsten nitride film after the formation. 9. The method according to claim 6, further comprising the step of increasing the nitrogen concentration of a surface layer of said tungsten nitride film.
13. The method for manufacturing a semiconductor device according to claim 1. 10. The method according to claim 9, wherein the step of increasing the nitrogen concentration in the surface layer of the tungsten nitride film includes annealing in a gas atmosphere containing nitrogen atoms or plasma irradiation of a gas containing nitrogen atoms. The manufacturing method of the semiconductor device described in the above. 11. The method according to claim 7, further comprising a step of oxidizing a surface of the tungsten nitride film. 12. The method according to claim 11, wherein the step of oxidizing the surface of the tungsten nitride film includes forming silicon oxide on the surface of the tungsten nitride film by annealing in an atmosphere of oxygen or a gas containing oxygen. The manufacturing method of the semiconductor device described in the above.