JP2001358090A - Method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently bury a tungsten film into a minute connecting hole of a semiconductor device. SOLUTION: A contact layer 10, which has laminated films of TiN and Ti, is formed in contact holes 11 by directional sputtering. And then, a tungsten film 14 is grown in the contact holes 11 by CVD using reaction of WF6 gas and SiH4 gas. At this moment, the WF6 gas is supplied to a reaction chamber after the SiH4 gas. Hence, it is possible to effectively prevent abnormal reaction between the WF6 gas and the contact layer 10 (Ti) and abnormal reaction between the WF6 gas and the silicon substrate 1. Subsequently, a tungsten film 13 is grown by CVD using reaction of WF6 gas and H2 gas to fill the contact holes 11. Thereafter, the surface of an interlayer insulating film 6 is flattened, and a wiring layer 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 for manufacturing a semiconductor device which is effective for filling contact holes and via holes using a tungsten film.

[0002]

2. Description of the Related Art Wiring in a semiconductor integrated circuit has been extremely miniaturized and multilayered. In such a semiconductor integrated circuit, in order to connect a wiring and a substrate, a method of first forming a contact hole and then filling a conductive film such as a tungsten film by a CVD method or the like has been used.

FIG. 6 shows a configuration of a main part of this conventional semiconductor device. In FIG. 6, 1 is a silicon substrate, 2 is an element isolation film, 3 is a diffusion layer forming a source and a drain of a MOS transistor, 4 is a gate electrode, 5 is a gate electrode 4
6 is an interlayer insulating film, 7 is a wiring layer mainly composed of an aluminum alloy, 8 is an adhesion layer made of, for example, a TiN / Ti laminated structure film also called a barrier metal film, and 9 is C
A tungsten film formed by the VD method (hereinafter referred to as “CV
Reference numeral 11) is a contact hole.

In this conventional method of manufacturing a semiconductor device, an element isolation film 2 and a MOS transistor including a diffusion layer 3, a gate electrode 4, an insulating film 5 and the like are formed on a silicon substrate 1, and then an interlayer insulating film is formed on the entire surface. A film 6 is deposited, and a part of the interlayer insulating film 6 is etched to open a contact hole 11.
Next, an adhesion layer 8 of, for example, TiN / Ti is formed on the bottom and the side wall of the contact hole 11 by a sputtering method.
The adhesion layer 8 is made of W when Ti is used to form a tungsten film later.
After forming a Ti film, a TiN film is formed thereon so as not to come into direct contact with the F ₆ gas.

After that, the tungsten film 9 is formed by CVD.
Is deposited so as to be embedded in the contact hole 11.
This deposition includes a first step (nucleation step) by a reaction between WF ₆ gas and SiH ₄ gas, and a WF ₆ gas and H ₂ gas.
It comprises a second step (via fill step) by a gas reaction, and the tungsten film 9 is composed of two types of films by the first and second steps.

After the CVD tungsten film 9 is deposited, C
The surfaces of the tungsten film 9 and the interlayer insulating film 6 are flattened by an MP (Chemical Mechanical Polishing) method or etch back. After that, the wiring layer 7 is formed. The wiring layer 7 includes a TiN / Ti barrier layer as a lower layer, an aluminum layer as an intermediate layer thereon, and a TiN / Ti cap layer as an upper layer thereon, that is, TiN / Ti /
It is a laminate of Al / TiN / Ti.

[0007]

However, in recent years, as interconnects have become finer, it has become increasingly difficult to fill contact holes with a tungsten film or the like, as shown in FIG. When the sputtering amount is increased in order to form the adhesion layer 8 having a sufficient thickness at the bottom of the contact hole 11, the adhesion layer 8 above the contact hole 11 has an overhang shape, the opening area is reduced, and the tungsten film 9 is formed. Incomplete buried portions 18 such as seams (or voids) are generated therein.

As described above, when the filling of the contact holes with tungsten becomes incomplete, CMP (Chemical
The abrasive may penetrate into the incomplete buried portion when planarizing the entire surface of the tungsten by Mechanical Polishing), or the incomplete buried portion may be removed during the etch back of tungsten using SF ₆ -based gas. Etch-back is faster than the above-mentioned location, so that penetration into the lower substrate or the lower wiring may occur. Due to such a phenomenon, the resistance of a contact hole or a via hole of a semiconductor integrated circuit increases, or the reliability of a multilayer wiring such as electromigration or stress migration deteriorates.

For this reason, it is necessary to bury tungsten as completely as possible in the contact holes and via holes. In order to completely embed the tungsten film in the contact hole, a method of increasing the area of the upper opening of the contact hole by reducing the thickness of the underlying adhesion layer such as TiN / Ti has been studied. However, FIG.
First, in the formation of the tungsten film 9, the first step is performed by the reaction between the WF ₆ gas and the SiH ₄ gas.
At this time, when WF ₆ gas is first introduced into the reaction chamber and then SiH ₄ gas is introduced, the WF ₆ gas becomes Si or Ti.
Reaction easily occurs to form a high-resistance layer,
It may cause junction leakage due to n-junction breakdown. The adhesion layer 8 forms a TiN film on the Ti film so that Ti does not directly contact the WF ₆ gas. However, since TiN is a columnar crystal, WF ₆ penetrates deeply along the grain boundary. Reacts with Ti and Si.

Further, the tungsten film deposited by the CVD method has large crystal grains, so that the surface of the film is extremely uneven. Therefore, when etch-back is performed, there are also problems that an etching residue occurs and that the surface morphology after the formation of the wiring layer 7 deteriorates.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides a method of manufacturing a semiconductor device capable of satisfactorily embedding a tungsten film in a fine connection hole (contact hole, via hole) even if the wiring becomes finer. The purpose is to provide.

[0012]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: opening a interlayer insulating film formed on a lower conductive layer to form a connection hole; Forming a laminated layer of titanium nitride and titanium or a first tungsten film by a physical vapor deposition method (sputtering method); and reacting a WF ₆ gas with a silicon hydride on the adhesion layer. Chemical vapor deposition using gas (C
Growing a second tungsten film by a VD method) and growing a third tungsten film on the second tungsten film by a CVD method using WF ₆ gas and H ₂ gas to bury the connection holes. Wherein the silicon hydride-based gas is introduced into the reaction chamber before or simultaneously with the WF ₆ gas when growing the second tungsten film. The upper conductive layer is a wiring layer, and the lower conductive layer is a wiring layer or a diffusion layer formed on the surface of the silicon substrate.

According to the manufacturing method of the claim 1, after forming the adhesion layer, the WF ₆ gas and a silicon hydride-containing gas to grow a second tungsten film, where the silicon hydride a WF ₆ gas When introduced into the reaction chamber with a time delay relative to the system gas, an abnormal reaction between the WF ₆ gas and the Ti of the adhesion layer when the adhesion layer is a laminated film of titanium nitride and titanium, and a lower conductive layer Is a diffusion layer formed on the silicon substrate surface, an abnormal reaction between the WF ₆ gas and the silicon substrate can be prevented. In this way, the reaction between WF ₆ and the adhesion layer or the lower conductive layer (silicon substrate or wiring layer) can be suppressed, particles due to abnormal growth can be reduced, and the state of filling the tungsten film in the fine connection hole can be improved. And good contact characteristics or via characteristics can be obtained.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, when growing the second tungsten film, WF _{6 with} respect to a silicon hydride-based reaction gas is grown. It is characterized in that the gas flow ratio is changed from a small state to a large state.

By doing so, it is possible to realize an excellent tungsten-embedded shape while suppressing an abnormal reaction between WF ₆ and the underlying film. In this manner, damage to the adhesion layer and the lower conductive layer (silicon substrate or wiring layer) by WF ₆ can be reduced, and the step coverage of the second tungsten film can be improved.

According to a third aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the first aspect, wherein the first tungsten film is used as the adhesion layer by a physical vapor deposition method having a high directivity (for example, , Ionization sputtering, collimation sputtering, or long-distance sputtering.

Thus, it is possible to secure a sufficient thickness of the adhesion layer at the bottom of the connection hole and to reduce the thickness of the adhesion layer formed on the interlayer insulating film, and the upper portion of the connection hole has an overhang shape. The opening area can be reduced, and the pinch-off phenomenon can be prevented. Further, by forming the adhesion layer as the first tungsten film formed by the physical vapor deposition method having high directivity, the stress of the tungsten film in the connection hole can be changed from the tensile stress to the contraction stress direction. The tensile stress applied to the wiring layer which is a conductive layer can be reduced, and the reliability of the wiring layer can be improved.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the third aspect, wherein the step of growing the second tungsten film is not performed, and the first tungsten film is formed on the first tungsten film. The method is characterized in that a third tungsten film is grown.

By forming the adhesion layer as the first tungsten film formed by a physical vapor deposition method having high directivity as in claim 3, the adhesion layer can be formed with respect to the WF ₆ gas when the tungsten film is grown by the CVD method. Since it acts as a good barrier metal and can prevent substrate erosion, etc.
As described above, the step of forming the second tungsten film using the WF ₆ gas and the silicon hydride-based gas can be eliminated.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the first aspect, wherein the step of growing the second tungsten film is replaced with the step of growing a second tungsten film.
CVD using F ₆ gas and silicon hydride based reaction gas
A step of growing a tungsten silicide film by a method is provided.

[0021] Thus, after forming the adhesion layer, by forming a tungsten silicide film, when then performed WF ₆ gas and H ₂ gas reaction in the third tungsten film deposition, the adhesion layer and the WF ₆ gas Reaction with the conductive layer (silicon substrate or wiring layer) below the metal layer or the lower layer can be more efficiently prevented.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the first, second, third, fourth or fifth aspect of the present invention, comprising the steps of: A step of depositing a fourth tungsten film on the third tungsten film by physical vapor deposition.

As described above, by depositing the third tungsten film by the CVD method and then depositing the fourth tungsten film by the physical vapor deposition method, the CV having a severe surface unevenness is formed.
The surface of the third tungsten film formed by the method D can be smoothed, and the surface of the tungsten film after CMP or etch back for flattening becomes smooth, so that the residue is reduced and the upper conductive film formed thereon is formed. The step coverage of the layer (wiring layer) can be improved. That is, the surface morphology of the wiring layer can be improved.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a cross-sectional view of a semiconductor device according to a first embodiment of the present invention for explaining a method of manufacturing the same. In FIG. 1, reference numeral 10 denotes T formed by physical vapor deposition with high directivity.
An adhesion layer made of an iN / Ti laminated structure film or a tungsten film, 13 is a tungsten film deposited by a reaction between WF ₆ gas and H ₂ gas by CVD, and 14 is a reaction between WF ₆ gas and SiH ₄ gas by CVD. Is a tungsten film deposited by the above method. Other parts corresponding to those in FIG. 6 are denoted by the same reference numerals.

In FIG. 1, a silicon single crystal
On the recon substrate 1, for example, SiO _TwoEmbedding consisting of
An element isolation film 2 and a gate electrode 4 are formed. Game
For example, to cover the electrode 4_TwoInsulating film 5 made of
Are formed. Silicon substrate on both sides of gate electrode 4
On one surface, for example, the source and drain of a MOS transistor
Diffusion layer 3 constituting an impurity, that is, a high concentration n-type or
MOS transistor with p-type semiconductor region formed
The on-resistance during operation can be reduced, or the contact hole 11 can be reduced.
Between the contact hole 11 and the diffusion layer 3 at the bottom of
A reduction in contact resistance, so-called contact resistance, is realized.

After forming such an element isolation film 2 and a MOS transistor, here, after forming an insulating film 5 covering the gate electrode 4, for example, a BPSG (Boron
An insulating film containing boron such as Phosphorous Silicate Glass is deposited. After that, photoresist (not shown)
Using as a mask, a part of interlayer insulating film 6 is opened by etching to form contact hole 11.

Next, an adhesion layer 10 made of a laminated film of TiN and Ti or W is formed in the contact hole 11 by a directional sputtering method. The adhesion layer 10 is necessary as a base film for the subsequent CVD tungsten deposition, and is used for improving the adhesion between the CVD tungsten film and the base silicon substrate or the base interlayer insulating film, or used when depositing the CVD tungsten film. It is important as a barrier metal for suppressing the reaction between the WF ₆ gas and the underlying silicon substrate. When the adhesion layer 10 is a laminated film of TiN and Ti, T
After forming a Ti film, a TiN film is formed thereon so that i does not come into direct contact with the WF ₆ gas when the tungsten film is formed later.

Next, a tungsten film 14 is grown in the contact hole 11 by a CVD method using a reaction between WF ₆ gas and SiH ₄ gas. At this time, the WF ₆ gas is grown from SiH ₄ gas for about 1 to 5 seconds. Introduce into the reaction chamber with a delay. As a result, WF which is likely to occur in the contact opening is
Abnormal reaction between ₆ gas and adhesion layer 10 (Ti) (for example, 2WF
₆ + 3Ti → 2W + Volcano phenomenon caused by the reaction of 3TiF _4: References S. M. Sze ULSI Tech
(nology P409), or an abnormal reaction (for example, 2WF ₆ + 3Si → 2W + 3SiF ₄ ) between the WF ₆ gas and the silicon substrate 1 which is likely to occur at the bottom of the contact can be effectively prevented.

Next, C by the reaction of WF ₆ gas and H ₂ gas
A tungsten film 13 is grown by the VD method to fill the contact hole 11. This is shown in FIG. 1 (however, the irregularities on the surface of the tungsten film 13 are ignored). Further, the tungsten film 14 and the tungsten film 13
FIG. 2 shows a timing chart for introducing a reaction gas into the reaction chamber when growing the methane. Then, after depositing the CVD tungsten film 13, the tungsten films 13, 14 and the adhesion layer 10 on the interlayer insulating film 6 other than the contact holes 11 are removed by a CMP method or etch back, and the tungsten film 13 and the interlayer insulating film are removed. 6 is flattened. Thereafter, a wiring layer 7 (see FIG. 6) made of an aluminum alloy or the like is formed.

According to this embodiment as described above, after forming the adhesion layer 10, a tungsten film 14 is grown by WF ₆ gas and SiH ₄ gas reaction, where the time the WF ₆ from SiH ₄ To the reaction chamber, the abnormal reaction between the WF ₆ gas and the Ti of the adhesion layer 10 or the W
An abnormal reaction between the F ₆ gas and the silicon substrate 1 can be prevented. As described above, the reaction between the WF ₆ and the underlying film is suppressed, particles due to abnormal growth can be reduced, the state of burying the fine contact holes 11 can be improved, and good contact characteristics can be obtained.

[0031] Note that when growing the growth of the tungsten film 14, WF ₆ to be introduced gases prior to the SiH ₄ gas, Ti and silicon substrate 1 of the adhesive layer 10 and the WF ₆ gas
WF ₆ gas and SiH ₄ gas may be simultaneously introduced into the reaction chamber.

In the present embodiment, SiH ₄ is used as a silicon hydride-based reaction gas, but SiH ₂ Cl ₂ (dichlorosilane) may be used instead.

In the first embodiment, WF ₆
When the tungsten film 14 is deposited by the reaction of hydrogen and a silicon hydride-based reaction gas (for example, SiH ₄ ), it is preferable to divide the deposition process into two or more steps. In the divided steps, W
The flow rate ratio between F ₆ and SiH ₄ , that is, the WF ₆ / SiH ₄ ratio is set to be large. For example, tungsten film 1
If the four deposition process is divided into two steps, the first step is 10 sccm WF _{6 and} 10 s SiH ₄
ccm and in the second step WF ₆ is 30 scc
m so that the SiH ₄ is 10 sccm. By doing so, it is possible to realize an excellent tungsten-embedded shape while suppressing an abnormal reaction between the base substrate and WF ₆ . That is, the damage to the silicon substrate 1 by the WF ₆ can be reduced, and the step coverage of the tungsten film 14 can be improved.

Since the aspect ratio (depth / opening diameter) of the contact hole 11 increases as the semiconductor integrated circuit becomes finer, the adhesion layer 10 should be formed sufficiently (about 10 nm) to the bottom of the contact hole 11. Conventionally, a thick film (100 nm to 2 nm) is formed on the interlayer insulating film 6.
00 nm), the upper portion of the contact hole 11 has an overhang shape as shown in FIG. 6, and the opening area of the upper portion decreases. In some cases, the upper part of the contact hole 11 is
May also close (pinch-off phenomenon). Therefore, it is preferable that the adhesion layer 10 is as thin as possible without causing erosion of the substrate by the WF ₆ gas during the deposition of CVD tungsten. Therefore, the adhesion layer 10 is formed by a directional sputtering method (a sputtering method having a high directivity: for example, an ionization sputtering method, a collimation sputtering method, or a long-distance sputtering method), so that a sufficient TiN / Ti or While securing the tungsten film thickness, the film thickness on the interlayer insulating film 6 is reduced (for example, 20 n).
m) is preferably realized.

Further, by forming the adhesion layer 10 as a tungsten film by the directional sputtering method, the stress of the tungsten film 13 or the like after the deposition of the CVD tungsten is, for example, 1 × 10 ¹⁰
To change from [dyne / cm ^2] of tensile stress to the shrinkage stress direction, the wiring layer 7 (e.g., TiN / Al-Cu0.5wt
% / TiN / Ti = 30 nm / 600 nm / 20 nm /
20 nm) is reduced, and the stress migration resistance is improved. Further, in this case, the adhesion layer 10 (tungsten film by the directional sputtering method) acts as a good barrier metal against WF ₆ gas at the time of growing the CVD tungsten film, and can prevent substrate erosion and the like, and can prevent WF ₆ and SiH ₄ from being mixed. Tungsten can be embedded without using a reaction step. Therefore, without forming a tungsten film 14 by WF ₆ gas and SiH ₄ gas reaction, as shown in FIG. 3, after forming a tungsten film as an adhesion layer 10 by directional sputtering method, the WF ₆ gas and H ₂ gas reaction The contact hole 11 can be buried by growing the CVD tungsten film 13.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
FIG. 39 is a cross-sectional view in the course of manufacture for illustrating the method of manufacturing the semiconductor device in the embodiment. 4, reference numeral 15 denotes a tungsten silicide (WSix) film, and other portions corresponding to those in FIG. 1 are denoted by the same reference numerals.

In the present embodiment, the same as in the first embodiment is used.
From TiN / Ti laminated structure film or tungsten film
After the adhesion layer 10 is deposited, the first embodiment
WF instead of forming the tungsten film 14₆Gas and S
iH_FourTungsten silicide by CVD method using gas
An id film 15 is formed. This tungsten silicide film
Reference numeral 15 denotes the tungsten film 14 according to the first embodiment.
SiH than when forming _FourIncrease the gas flow, WF₆gas
SiH against_FourBy increasing the gas flow ratio
Form. Tungsten film 1 according to first embodiment
In the formation of No. 4, WF₆/ SiH_FourThe gas flow ratio of 0.
5 or more (for example, 30 sccm / 10 sccm or 40 sccm
cm / 30 sccm).
When forming the gustene silicide film 15, WF₆/ Si
H_FourIs set to 0.1 or less.

Next, as in the first embodiment, a tungsten film 13 is grown by CVD using a reaction between WF ₆ gas and H ₂ gas to fill the contact hole 11. This is shown in FIG. 4 (however, the irregularities on the surface of the tungsten film 13 are ignored). Thereafter, similarly to the first embodiment, the surfaces of the tungsten film 13 and the interlayer insulating film 6 are flattened by the CMP method or the etch back, and the wiring layer 7 (see FIG. 6) made of an aluminum alloy or the like is formed.

As described above, according to the present embodiment, after the adhesion layer 10 is formed, the tungsten silicide film 15 is formed, so that when the tungsten film is deposited by a WF ₆ gas and H ₂ gas reaction performed later. , The abnormal reaction between the WF ₆ gas and the underlying film can be more efficiently prevented. That is, since the tungsten silicide film 15 contains silicon as a part of the composition, the WF ₆ gas reacts preferentially with the silicon contained in the composition without reacting with the silicon substrate 1. Erosion to the like can be prevented. Therefore,
Decrease the thickness of the tungsten film 14 or reduce it to 0 (none)
(This embodiment shows a case where the tungsten film 14 is 0), and the CVD tungsten film 13
Can be improved.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
FIG. 39 is a cross-sectional view in the course of manufacture for illustrating the method of manufacturing the semiconductor device in the embodiment. In FIG. 5, reference numeral 12 denotes a tungsten film deposited by a sputtering method, and other portions corresponding to those in FIG. 1 are denoted by the same reference numerals.

This embodiment is different from the first embodiment shown in FIG. 1 in that after depositing a CVD tungsten film 13, a tungsten film 12 is deposited thereon by sputtering. Thereafter, similarly to the first embodiment, the tungsten film 13 is formed by the CMP method or the etch back.
In addition, the surface of the interlayer insulating film 6 is flattened to form a wiring layer 7 (see FIG. 6) made of an aluminum alloy or the like.

According to the present embodiment, after the CVD tungsten film 13 is deposited, the tungsten film 12 is deposited by the sputtering method, so that the surface of the CVD tungsten film 13 having severe surface irregularities can be smoothed. . By doing so, the surface of the tungsten film after the CMP or the etch back becomes smooth, so that the residue can be reduced and the step coverage of the wiring layer 7 (see FIG. 6) formed thereon can be improved.

Although the present embodiment has been described with reference to FIG. 1, the present invention can be applied to all the examples described in the first and second embodiments.

In each of the above embodiments, the process of filling the contact hole 11 connecting the diffusion layer 3 and the wiring layer 7 on the surface of the silicon substrate 1 has been described.
The present invention can be similarly applied to a process of filling a via hole connecting a lower wiring layer and an upper wiring layer with an interlayer insulating film interposed therebetween.

Further, the present invention can be applied to all methods of manufacturing a semiconductor device which involve a process of filling contact holes and via holes using tungsten.

[0046]

According to the present invention, after forming the adhesion layer,
The WF ₆ gas and a silicon hydride-containing gas to grow a second tungsten film, where, by introducing into the reaction chamber by delaying the WF ₆ gas in time than hydrogenated silicon gas, WF ₆ and the adhesion layer And the reaction with the lower conductive layer (silicon substrate or wiring layer) can be suppressed, particles due to abnormal growth can be reduced, the state of filling fine connection holes can be improved, and good contact characteristics or via characteristics can be obtained.

Further, when growing the second tungsten film, by changing the flow ratio of the WF ₆ gas to the silicon hydride-based reaction gas from a small state to a large state, an abnormal reaction between the WF ₆ and the base film can be achieved. And an excellent tungsten buried shape can be realized.

Further, by forming the first tungsten film as a contact layer by a physical vapor deposition method having a high directivity, a sufficient thickness of the contact layer is secured at the bottom of the connection hole.
In addition, the thickness of the adhesion layer formed on the interlayer insulating film can be reduced, and the upper portion of the connection hole has an overhang shape, so that the opening area can be reduced and the pinch-off phenomenon can be prevented. In addition, the stress of the tungsten film in the connection hole can be changed from the tensile stress to the contraction stress direction, thereby reducing the tensile stress applied to the wiring layer, which is the upper conductive layer, and improving the reliability of the wiring layer. it can.

The adhesion layer is formed by physical vapor deposition with high directivity.
The first tungsten film formed by the method
In addition, when the adhesion layer is used for growing a tungsten film by a CVD method,
WF ₆Acts as a good barrier metal against gas,
Since erosion of the substrate can be prevented, WF₆Gas and hydrogenated silicon
Step of forming a second tungsten film using a copper-based gas
The process can be eliminated.

Further, instead of the step of growing the second tungsten film, a step of growing a tungsten silicide film by a CVD method using a WF ₆ gas and a silicon hydride-based reaction gas is provided, which is performed thereafter. WF ₆
At the time of depositing the third tungsten film by the reaction between the gas and the H ₂ gas, an abnormal reaction between the WF ₆ gas and the underlying film can be more efficiently prevented.

After the third tungsten film is grown, a step of depositing a fourth tungsten film by physical vapor deposition on the third tungsten film by CVD is provided, so that the CVD method has a rough surface. The surface of the third tungsten film formed by the method can be smoothed, and the surface of the tungsten film after the CMP or etch back for flattening becomes smooth, so that the residue is reduced and the upper conductive layer formed thereon is formed. The step coverage of the (wiring layer) can be improved. That is, the surface morphology of the wiring layer can be improved.

With the above effects, further miniaturization of the multi-layer wiring forming process of the semiconductor device can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a manufacturing method of a semiconductor device according to a first embodiment of the present invention during manufacture.

FIG. 2 is a timing chart for introducing a reaction gas for growing a tungsten film 14 and a tungsten film 13 in FIG. 1 into a reaction chamber.

FIG. 3 is a cross-sectional view showing a step in the process of manufacturing another example of a semiconductor device according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of a semiconductor device during a manufacturing process according to a second embodiment of the present invention, illustrating the method of manufacturing the semiconductor device;

FIG. 5 is a cross-sectional view in the middle of a manufacturing process illustrating a method for manufacturing a semiconductor device according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a configuration of a main part of a conventional semiconductor device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Element isolation film 3 Diffusion layer 4 Gate electrode 5 Insulating film 6 Interlayer insulating film 7 Wiring layer 9 CVD tungsten film 10 Adhesion layer 11 Contact hole 12 Tungsten film deposited by sputtering 13 WF ₆ gas and H ₂ gas Tungsten film deposited by reaction 14 Tungsten film deposited by reaction of WF ₆ gas and SiH ₄ gas 15 Tungsten silicide film

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C23C 16/455 C23C 16/455 H01L 21/768 H01L 21/90 DB F term (Reference) 4K030 AA04 AA06 AA17 BA18 BA20 BA38 BA48 BB12 CA04 EA03 HA03 HA04 JA05 JA06 LA15 4M104 AA01 BB14 BB18 CC01 DD06 DD19 DD39 DD45 DD66 DD75 EE15 FF18 FF22 HH02 HH12 HH13 5F033 HH09 JJ18 JJ19 JJ28 JJ33 QHQ NNQ15 XX02 XX04 XX06 XX18 XX21

Claims (6)

[Claims] 1. A method of manufacturing a semiconductor device in which a lower conductive layer is electrically connected to an upper conductive layer via a connection hole of an interlayer insulating film formed thereon, the method comprising: Forming the connection hole by opening the interlayer insulating film formed on the conductive layer; and forming a laminated film of titanium nitride and titanium or a first tungsten film in the connection hole by physical vapor deposition. A step of forming an adhesion layer; a step of growing a second tungsten film on the adhesion layer by a chemical vapor deposition method using a WF ₆ gas and a silicon hydride-based reaction gas; Growing a third tungsten film on the tungsten film by a chemical vapor deposition method using WF ₆ gas and H ₂ gas to fill the connection hole, and growing the second tungsten film. When hydrogenated silicon-based gas is converted to W The method of manufacturing a semiconductor _device characterized by ₆ introduced earlier or simultaneously the reaction chamber from the gas. 2. The semiconductor device according to claim 1, wherein when growing the second tungsten film, the flow ratio of the WF ₆ gas to the silicon hydride-based reaction gas is changed from a small state to a large state. Manufacturing method. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the first tungsten film is formed by a physical vapor deposition method having high directivity as the adhesion layer. 4. The method according to claim 3, wherein a third tungsten film is grown on the first tungsten film without performing the step of growing the second tungsten film. 5. A step of growing a tungsten silicide film by a chemical vapor deposition method using a WF ₆ gas and a silicon hydride-based reaction gas instead of the step of growing a second tungsten film. The method for manufacturing a semiconductor device according to claim 1, wherein: 6. After growing a third tungsten film,
6. The method according to claim 1, further comprising a step of depositing a fourth tungsten film on said third tungsten film by a physical vapor deposition method.