JP3504175B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device,
In particular, the present invention relates to a semiconductor device whose wiring structure is a laminated wiring structure.

[0002]

2. Description of the Related Art With the recent increase in integration and speed of semiconductor devices, copper (Cu) wiring having a lower electric resistance than that of conventional aluminum (Al) wiring is being introduced. However, copper (C
u) Diffusion of atoms into the silicon (Si) substrate or insulating film may deteriorate the device characteristics.Therefore, a diffusion prevention film to prevent diffusion of copper (Cu) atoms is adjacent to the copper (Cu) film. Is formed. As a material for this diffusion prevention film, as described in Nikkei Microdevices (June 1992 issue, pages 74 to 77), titanium nitride (TiN) film, tungsten (W) film, tantalum (Ta) film, etc. Melting point metal films are being investigated.

[0003]

Since a high-density current flows in a semiconductor device which is miniaturized for high integration, atoms are diffused by the flow of electrons and heat generated thereby, so that voids and disconnections are generated. There is a so-called electromigration problem that occurs. Since the copper (Cu) film has a higher melting point than the aluminum (Al) film, it is less likely to diffuse and is expected to have excellent electromigration resistance. However, titanium nitride (T
iN) film, tungsten (W) film, tantalum (Ta) film, etc.
u) In the laminated wiring structure in contact with the film, sufficient electromigration resistance cannot be obtained, and there is a problem that voids and disconnections are likely to occur. An object of the present invention is to provide a highly reliable semiconductor device in which voids and disconnections are unlikely to occur in the laminated wiring structure.

[0004]

Means for Solving the Problems The inventors of the present invention have proposed a laminated wiring structure in which a titanium nitride (TiN) film, a tungsten (W) film, a tantalum (Ta) film, etc. are brought into contact with a copper (Cu) film as a diffusion prevention film. In Fig. 2, the diffusion barrier film material and the edge length of the unit crystal lattice of copper (Cu) are significantly different, which disturbs the atomic arrangement at the interface, and it is easy to cause voids and disconnections due to active diffusion. I chose Therefore, in order to prevent voids and disconnection of the copper (Cu) wiring, it is only necessary to suppress diffusion by using a material having a small difference in length between the sides of the unit crystal lattice with copper (Cu) for adjacent films. . The inventors of the present invention, in a laminated wiring structure in which a conductive film and an adjacent film are stacked in contact with the conductive film, the short side a _p of the rectangular lattice forming the minimum free energy surface of the conductive film and the aforesaid The difference between the short sides a _n of the rectangular lattice that constitutes the minimum free energy surface of the adjacent film {| a _p -a _n ｜ / a _p } × 100 = A
(%) Is less than 13%, and the long side b _p of the rectangular lattice forming the minimum free energy surface of the conductive film and the long side of the rectangular lattice forming the minimum free energy surface of the adjacent film
The difference in b _n {| b _p -b _n ｜ / b _p } × 100 = B (%) multiplied by (a _p / b _p ), the diffusion of the conductive film is suppressed when the amount is less than 13. ,
It has been clarified that voids and disconnections are suppressed. Also,
In particular, it was clarified that A and B are more preferable when they satisfy the inequality of {A + B × (a _p / b _p )} <13. In the above,
The definition of the short side a and the long side b of the rectangular lattice is shown in FIG.

Therefore, an object of the present invention is to provide a semiconductor device having a laminated wiring structure in which a conductive film and an adjacent film are stacked in contact with the conductive film on a semiconductor substrate. The short side a _p of the rectangular lattice
And the difference between the short sides a _n of the rectangular lattice forming the minimum free energy surface of the adjacent film {| a _p -a _n | / a _p } × 100 = A (%) and the minimum free energy of the conductive film. the difference of the long sides b _n of rectangular lattice constituting the long side b _p of rectangular lattice that constitute the surface free energy minimum surface of the adjacent film _{{| b p -b n | /} b p} × 100 = B (%) Is (A
This is achieved by selecting the materials of the conductive film and the adjacent film so as to satisfy the inequality of + B × (a _p / b _p )} <13.

Further, the above-mentioned purpose is to provide copper (C) on a semiconductor substrate.
u) a semiconductor device having a laminated wiring structure in which an adjacent film is laminated in contact with the copper (Cu) film, the adjacent film is made of rhodium.
This is achieved by using a (Rh) film, a ruthenium (Ru) film, an iridium (Ir) film, an osmium (Os) film or a platinum (Pt) film.

[0007] Further, the above object is to provide platinum on a semiconductor substrate.
In a semiconductor device having a laminated wiring structure in which an adjacent film is laminated in contact with the (Pt) film and the platinum (Pt) film, the adjacent films are rhodium (Rh) film, ruthenium (Ru) film, iridium (Ir) film Alternatively, it is achieved by using an osmium (Os) film.

Specifically, it is desirable to have the following configuration. In a semiconductor device having a laminated structure having a copper (Cu) film wiring formed on one main surface side of a semiconductor substrate and a barrier metal formed in contact with the copper (Cu) film wiring, the barrier metal is ruthenium. It is a (Ru) film, and the copper (Cu) film wiring has a laminated structure of a copper (Cu) film formed by sputtering and a copper (Cu) film formed by plating. In a semiconductor device having a laminated structure having a copper (Cu) film wiring formed on one main surface side of a semiconductor substrate and a barrier metal formed in contact with the copper (Cu) film wiring, the barrier metal is ruthenium. (Ru) film, the copper (Cu) film wiring is a copper (Cu) film formed using physical vapor deposition (PVD) and chemical vapor deposition (CVD) copper (Cu) formed using Must have a laminated structure with the membrane. In a semiconductor device having a laminated structure having a copper (Cu) film wiring formed on one main surface side of a semiconductor substrate and a barrier metal formed in contact with the copper (Cu) film wiring, the barrier metal is a sputtering material. Ruthenium formed using
(Ru) film, the copper (Cu) film wiring is a copper (Cu) film formed by sputtering and plating or chemical vapor deposition method
It must have a laminated structure with a copper (Cu) film formed using (CVD). In a semiconductor device having a structure having a copper (Cu) film wiring formed on one main surface side of a semiconductor substrate and a plug formed in contact with the copper (Cu) film wiring, the plug is rhodium.
(Rh) film, ruthenium (Ru) film, iridium (Ir) film, osmium (Os) film, one kind of film selected from the group consisting of platinum (Pt) film, the copper (Cu) film wiring and the At least one of the plugs contains a layer formed using physical vapor deposition (PVD). Structure having a copper (Cu) film wiring formed on one main surface side of a semiconductor substrate, a barrier metal formed in contact with the copper (Cu) film wiring, and a plug formed in contact with the barrier metal In the semiconductor device including, the barrier metal is a ruthenium (Ru) film, the plug is a ruthenium (Ru) film, physical vapor deposition (PVD) on at least one of the copper (Cu) film wiring and the plug. Includes layers formed using. Copper (C
u) film wiring, a first barrier metal formed in contact with the copper (Cu) film wiring, a plug formed in contact with the first barrier metal, and a plug formed in contact with the plug and the first barrier metal In a semiconductor device having a structure having a formed second barrier metal, the first barrier metal is a ruthenium (Ru) film and the plug is ruthenium (Ru).
The second barrier metal is a titanium nitride (TiN) film, and at least one of the copper (Cu) film wiring and the first barrier metal is a film formed by sputtering. A platinum (Pt) electrode film formed on the one main surface side of the semiconductor substrate,
In a semiconductor device having a structure having an adjacent film formed in contact with the platinum (Pt) electrode film, the adjacent film is a rhodium (Rh) film, a ruthenium (Ru) film, an iridium (Ir) film, an osmium film. It is one kind of film selected from the group consisting of (Os) film, and at least one of the platinum (Pt) electrode film and the adjacent film is a film formed by sputtering. The semiconductor device manufacturing method includes the following steps.

A step of forming a ruthenium (Ru) film on the main surface side of the semiconductor substrate by sputtering.

A step of forming a first copper (Cu) film by sputtering so as to contact the ruthenium (Ru) film.

A step of forming a second copper (Cu) film by using plating or chemical vapor deposition (CVD) so as to be in contact with the first copper (Cu) film.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a sectional structure of a laminated wiring structure portion in a semiconductor device according to a first embodiment of the present invention. As shown in FIG. 1, the laminated wiring structure in the semiconductor device of this embodiment has a silicon substrate 1
An insulating film 2 made of, for example, silicon oxide is formed thereon, and a first laminated wiring structure 6 including an adjacent film 3, a conductive film 4, and an adjacent film 5 is connected through a contact hole formed in the insulating film 2. There is. An insulating film 7 made of, for example, silicon oxide is formed on the first laminated wiring structure 6, and a via hole formed in the insulating film 7 is made of, for example, tungsten.
The via 8 made of (W) is formed. The second laminated wiring structure 12 including the adjacent film 9, the conductive film 10, and the adjacent film 11 is connected through the via. Here, regarding the first laminated wiring structure 6, the short side a _p of the rectangular lattice forming the minimum free energy surface of the conductive film 4 and the rectangular lattice forming the minimum free energy surface of the adjacent films 3 and 5 are formed. Difference of short sides a _n {｜ a _p -a _n ｜
/ a _p } × 100 = A (%) and the long side b _p of the rectangular lattice forming the minimum free energy surface of the conductive film 4 and the adjacent films 3 and 5
Difference of the long sides b _n of the rectangular lattice constituting the minimum free energy surface of {| b _p -b _n ｜ / b _p } × 100 = B (%) is {A + B × (a _p / b _p )} < 13
The adjacent film 3, the conductive film 4, and the adjacent film 5 are formed of a combination of materials that satisfy the following inequality. Specifically, when a copper (Cu) film is used as the conductive film 4, as the adjacent films 3 and 5, a rhodium (Rh) film, a ruthenium (Ru) film,
An iridium (Ir) film, an osmium (Os) film, or a platinum (Pt) film may be used. When a platinum (Pt) film is used as the conductive film 4, a rhodium (Rh) film, a ruthenium (Ru) film, an iridium (Ir) film, or an osmium (O) film is used as the adjacent films 3 and 5.
s) A film may be used.

Similarly, for the second laminated wiring structure 12, the short side a _p of the rectangular lattice forming the minimum free energy surface of the conductive film 10 and the minimum free energy surface of the adjacent films 9 and 11 are formed. Difference of short sides a _n of rectangular lattice {｜ a _p -a _n ｜ / a _p } ×
100 = A (%) and the long side b _p of the rectangular lattice forming the minimum free energy plane of the conductive film 10 and the long side b of the rectangular lattice forming the minimum free energy plane of the adjacent films 9 and 11. difference of _n
{| B _p -b _n │ / b _p } × 100 = B (%) is a combination of materials satisfying the inequality of {A + B × (a _p / b _p )} <13. The adjacent film 11 is formed.
Specifically, when a copper (Cu) film is used as the conductive film 10, the adjacent films 9 and 11 are rhodium (Rh) film, ruthenium (Ru) film, iridium (Ir) film, osmium (Os) film. Alternatively, a platinum (Pt) film may be used. When a platinum (Pt) film is used as the conductive film 10, rhodium (Rh) film, ruthenium (Ru) film, iridium (Ir) film or osmium (Os) film is used as the adjacent films 9 and 11. Good.

The effects of the semiconductor device of this embodiment will be described below. The authors pay attention to the difference between the conductive film and the adjacent film on the short side a and the long side b of the rectangular lattice forming the minimum free energy surface, and investigate the effect of this difference on the diffusion coefficient by computer simulation. It was Specifically, in a laminated wiring structure in which a conductive film and an adjacent film are stacked in contact with the conductive film, the short side a _p of the rectangular lattice forming the minimum free energy surface of the conductive film and the The difference between the short sides a _n of the rectangular lattice forming the minimum free energy surface of the adjacent film {| a _p -a _n ｜ / a _p } ×
With 100 = A (%) on the horizontal axis, the long side b _p of the rectangular lattice forming the minimum free energy plane of the conductive film and the long side b of the rectangular lattice forming the minimum free energy plane of the adjacent film. difference of _n
{| B _p -b _n ｜ / b _p } × 100 = B (%) multiplied by (a _p / b _p ), and make a map with the amount on the vertical axis. And B were set, and the value of the diffusion coefficient in the conductive film was calculated by computer simulation.

First, a simulation was performed at a temperature of 700 K when a copper (Cu) film was used as the conductive film. In this case, the minimum free energy plane of copper (Cu), which is a face-centered cubic lattice, is the (111) plane. The simulation result in this case is shown in FIG. The result shows that the diffusion coefficient of the copper (Cu) film sharply increases at the boundary of FIG. The region inside the boundary, that is, the region from the origin is a region where the diffusion coefficient is small and voids or the like are less likely to occur, and the region outside the boundary line is the region where the diffusion coefficient is large and voids or the like are likely to occur. In order to see this in detail, FIG. 3 shows the results of examining the diffusion coefficient of the copper (Cu) film along the broken line in FIG. Where D is the diffusion coefficient of the copper (Cu) film and D ₀ is the bulk copper (C
It is the diffusion coefficient in u). It can be seen that the diffusion coefficient sharply increases at the boundary, and titanium nitride (TiN), which has been conventionally used as the adjacent film, is located ahead of that. It can be seen from FIG. 2 that the tungsten (W) film and the tantalum (Ta) film are also outside the boundary line. On the other hand, inside the boundary line of FIG.
That is, on the origin side, a rhodium (Rh) film, a ruthenium (Ru) film,
An iridium (Ir) film, an osmium (Os) film, and a platinum (Pt) film are located, and it is understood that these are effective in suppressing diffusion of the copper (Cu) film. These materials have both A and B × (a _p / b _p ) of 1
In less than 3% area. If the boundary line in Fig. 2 is linearly approximated, (A
+ B × (a _p / b _p )} = 13. Therefore, (A + B × (a _p /
b _p)} when the conductive film and the adjacent film is formed on the diffusion is suppressed by the combination of satisfactory materials <13 becomes inequality, voids or disconnection can be suppressed. Here, we paid attention to the diffusion coefficient of the copper (Cu) film, and determined that the smaller it was, the less likely voids and the like would occur in the copper (Cu) film. More preferably, the adjacent film is made of a material having a high melting point. For example, rhodium (having a melting point of 196 ° C) has a higher melting point than platinum (having a melting point of 1769 ° C).
0 ° C.), ruthenium (melting point 2310 ° C.), iridium (melting point 2443 ° C.), osmium (melting point 3045 ° C.) are more preferable.

Next, a simulation using platinum (Pt) as a conductive film was performed. Platinum (Pt) is also a face-centered cubic lattice, and the minimum free energy plane is the (111) plane. Simulation results in this case are shown in FIGS. The result of FIG. 4 is the same as that of FIG. 2, and the inside of the boundary line, that is, the region from the origin is a region where the diffusion coefficient is small and voids or the like are unlikely to occur, and the region outside the boundary line has the diffusion coefficient. It is a large area where voids are likely to occur. In order to see this in detail, FIG. 5 shows the results of examining the diffusion coefficient of the platinum (Pt) film along the broken line in FIG. In Fig. 5, D is platinum (P
t) is the diffusion coefficient of the film, and D ₀ is the diffusion coefficient of bulk platinum (Pt). It can be seen that the diffusion coefficient sharply increases at the boundary. Rhodium is inside the boundary line in Fig. 4.
Film, ruthenium (Ru) film, iridium (Ir) film, osmium (O
It is shown that these materials are effective in suppressing the diffusion of the platinum (Pt) film. These materials are in the region where both A and B x (a _p / b _p ) are less than 13%. It can be seen that the position of the boundary line in FIG. 4 is in good agreement with the case of the copper (Cu) film. When these boundary lines are approximated by a straight line, {A + B × (a _p / b
_p )} = 13. Therefore, when the conductive film and the adjacent film are formed of a combination of materials that satisfy the inequality {A + B × (a _p / b _p )} <13, diffusion is suppressed and voids and disconnections are suppressed.

Next, FIG. 7 shows a sectional structure of a laminated wiring structure portion in a semiconductor device according to a second embodiment of the present invention. In the laminated wiring structure in the semiconductor device of this embodiment, as shown in FIG. 7, an insulating film 2 made of, for example, silicon oxide is formed on a silicon substrate 1, and the insulating film 2 is formed.
Diffusion prevention film 1 through the contact hole formed in
3, adjacent film 3, conductive film 4, adjacent film 5, diffusion prevention film 14
Is connected to the first laminated wiring structure 6. An insulating film 7 made of, for example, silicon oxide is formed on the first laminated wiring structure 6, and a via 8 made of, for example, tungsten (W) is formed in a via hole formed in the insulating film 7. The second laminated wiring structure 12 including the diffusion prevention film 15, the adjacent film 9, the conductive film 10, the adjacent film 11, and the diffusion prevention film 16 is connected through the via. Here, the diffusion prevention films 13, 14, 15, and 16 are made of, for example, titanium nitride (TiN), tungsten (W), or tantalum (Ta). Regarding the first laminated wiring structure 6, the short side a _p of the rectangular lattice forming the minimum free energy surface of the conductive film 4 and the short side a of the rectangular lattice forming the minimum free energy surface of the adjacent films 3 and 5. difference of _n {｜ a _p-
a _n | / a _p } × 100 = A (%) and the long side b _p of the rectangular lattice that forms the minimum free energy surface of the conductive film 4 and the minimum free energy surface of the adjacent films 3 and 5 Difference of the long sides b _n of the rectangular lattice {| b _p -b _n │ / b _p } × 100 = B (%) is {A + B × (a _p / b
_p )} <13 the adjoining film 3 with a combination of materials satisfying the inequality
It is characterized in that the conductive film 4 and the adjacent film 5 are formed. Specifically, when a copper (Cu) film is used as the conductive film 4, rhodium (Rh) film and ruthenium are used as the adjacent films 3 and 5.
(Ru) film, iridium (Ir) film, osmium (Os) film or platinum
A (Pt) film may be used. In addition, platinum (P
When t) film is used, rhodium (Rh) is used as the adjacent films 3 and 5.
A film, a ruthenium (Ru) film, an iridium (Ir) film, or an osmium (Os) film may be used.

Similarly, for the second laminated wiring structure 12, the short side a _p of the rectangular lattice forming the minimum free energy surface of the conductive film 10 and the minimum free energy surface of the adjacent films 9 and 11 are formed. Difference of short sides a _n of rectangular lattice {｜ a _p -a _n ｜ / a _p } ×
100 = A (%) and the long side b _p of the rectangular lattice forming the minimum free energy plane of the conductive film 10 and the long side b of the rectangular lattice forming the minimum free energy plane of the adjacent films 9 and 11. difference of _n
{| B _p -b _n │ / b _p } × 100 = B (%) is a combination of materials satisfying the inequality of {A + B × (a _p / b _p )} <13. The adjacent film 11 is formed.
Specifically, when a copper (Cu) film is used as the conductive film 10, the adjacent films 9 and 11 are rhodium (Rh) film, ruthenium (Ru) film, iridium (Ir) film, osmium (Os) film. Alternatively, a platinum (Pt) film may be used. When a platinum (Pt) film is used as the conductive film 10, rhodium (Rh) film, ruthenium (Ru) film, iridium (Ir) film or osmium (Os) film is used as the adjacent films 9 and 11. Good.

Next, FIG. 8 shows a sectional structure of a main part of a semiconductor device according to a third embodiment of the present invention. As shown in FIG. 8, the semiconductor device according to the present embodiment has diffusion layers 102, 103, 104, on the silicon substrate 101.
105 is formed, and the gate insulating films 106 and 10 are formed on this.
A MOS transistor is formed by forming the gate electrode 7 and the gate electrodes 108 and 109. The gate insulating films 106 and 107 are, for example, a silicon oxide film or a silicon nitride film, and the gate electrodes 108 and 109 are, for example, a polycrystalline silicon film, a metal thin film, a metal silicide film, or a laminated structure of these. The MOS transistors are isolated by an element isolation film 110 made of, for example, a silicon oxide film. The gate electrodes 108 and 109
Insulating films 111 and 112 made of, for example, a silicon oxide film are formed on the upper portion and the side wall of the. For example, BPSG (Boron-Doped Phospho) is formed on the entire upper surface of the MOS transistor.
Silicate Glass) film, SOG (Spin On Glass) film, or chemical vapor deposition (Chemical Vapor Deposision in English,
CVD for short and physical vapor deposition (Physical Vapor Deposi in English)
, an insulating film 113 made of a silicon oxide film, a nitride film, or the like formed by PVD). Insulating film 113
In the contact hole formed in the above, a plug made of the conductor film 115 covered with the adjacent films 114a and 114b for diffusion prevention is formed, and the diffusion layers 102, 103, 104, 1
05 is connected. Through this plug, the laminated wiring made of the conductive film 117 covered with the adjacent films 116a and 116b as the barrier metal (diffusion prevention film) is connected. In this laminated wiring, for example, after forming a wiring groove in the insulating film 118 and forming the adjacent film 116a thereon,
A conductive film 117 is formed, and an adjacent film 116 is formed on the conductive film 117.
form b. Adjacent film 116a as barrier metal, 1
When forming 16b and the conductive film 117, the adjacent film 116a as a barrier metal is formed as usual.
At least one of 116b and the conductive film 117 is at least physical vapor deposition (Physical Vapor Depositio in English).
n, PVD for short). When the conductive film 117 is formed using physical vapor deposition, as is usually done, the film is first formed by physical vapor deposition such as sputtering, and then another film forming method (for example, forming a film in a narrow groove). It is also possible to switch to plating or chemical vapor deposition, which is excellent in forming Electromigration resistance is particularly important when the film forming method is switched. You may continue to use physical vapor deposition without switching to another deposition method. On top of this, the insulating film 1
In the via hole formed in 21, a plug made of the conductive film 120 covered with the adjacent films 119a and 119b as a barrier metal is formed and connected to the laminated wiring. Through this plug, the second laminated wiring made of the conductive film 123 covered with the adjacent films 122a and 122b as the barrier metal is connected. Regarding the formation of the second laminated wiring, for example, a groove for wiring is formed in the insulating film 124, the adjacent film 122a is formed thereon by, for example, a chemical vapor deposition method, and the conductive film 123 is formed thereon. Formed,
An adjacent film 122b is formed thereon by, for example, a chemical vapor deposition method. Further, the step of forming the second laminated wiring may be performed before forming the insulating film 124. Conductive film 12
The film formation of No. 3 is, for example, using physical vapor deposition, and then another film formation method.
(For example, plating or chemical vapor deposition method). Further, when forming the plug made of the conductive film 120 covered with the adjacent films 119a and 119b and the second laminated wiring, grooves are formed in the insulating films 121 and 124, and the adjacent films 119a and 119b and the adjacent films are formed. 122a is collectively formed into a film,
Then, a method of forming the conductive film 120 and the conductive film 123 may be used. The insulating film 125 is made of, for example, a silicon oxide film.

In this third embodiment, the adjacent film 11
Conductive film 117 and adjacent film 12 covered with 6a and 116b
At least one of the conductive films 123 covered by 2a and 122b has a short side a of a rectangular lattice forming a minimum free energy surface of an adjacent film in order to suppress diffusion and prevent generation of voids due to migration. _{The difference} between _n and the short side a _p of the rectangular lattice forming the minimum free energy surface of the conductive film
{| A _p -a _n | / a _p } × 100 = A (%), the long side b _n of the rectangular lattice constituting the minimum free energy surface of the adjacent film and the minimum free energy surface of the conductive film. Long sides of the rectangular lattice
The difference of b _p {| b _p -b _n ｜ / b _p } × 100 = B (%) is {A + B × (a _p /
b _p )} <13%. Specifically, for example, copper (Cu) is used as the conductive film 117.
When a film is used, as the adjacent films 116a and 116b, a rhodium (Rh) film, a ruthenium (Ru) film, an iridium (Ir) film,
One kind of film selected from the group consisting of an osmium (Os) film and a platinum (Pt) film is used. Conductive films 115 and 120 of the plug
Is adjacent to the conductive film 117, the conductive films 115, 1
Since 20 can be regarded as a film adjacent to the conductive film 117, when a copper (Cu) film is used as the conductive film 117, the conductive films 115 and 120 are a rhodium (Rh) film and a ruthenium (Ru) film. Film, iridium (Ir) film, osmium (Os) film, platinum (Pt) film by using one kind of film selected from the group, to suppress the diffusion of the conductive film 117, to prevent the occurrence of voids due to migration To do. By doing this, the rhodium (Rh) film, the ruthenium (Ru) film, the iridium (I
Since the r) film, the osmium (Os) film, and the platinum (Pt) film have higher melting points than the copper (Cu) film, compared with the case where the copper (Cu) film is used as the conductive films 115 and 120 of the plug. The effect of improving the heat resistance of the plug is also added. In this case, the adjacent films 114a, 114b, 119a of the conductive films 115, 120,
It is preferable to use a titanium nitride (TiN) film as the film 119b because the adhesion with the insulating films 113 and 121 is good. When the adhesion is not a problem, the adjacent films 114a, 114b, 11
9a and 119b may not be present. When importance is attached to the low electrical resistance of the plug rather than the heat resistance of the plug, a copper (Cu) film is used as the conductive films 115 and 120 of the plug, and a film 114a adjacent to the conductive films 115 and 120 is used. 11
4b, 119a and 119b include rhodium (Rh) film, ruthenium (Ru) film, iridium (Ir) film, osmium (Os) film
One kind of film selected from the group consisting of a film and a platinum (Pt) film is used. Although not shown in FIG. 8, the adjacent films 116a, 1a
16b, 122a, 122b, 114a, 114b, 119
Similar to the case of FIG. 7, one or more different films may be formed between each of the a and 119b and the insulating film.

Although not shown in FIG. 8, the conductive film 11
In order to prevent atoms from diffusing into the insulating film from the side walls of Nos. 7 and 123, it is preferable that the side walls of the conductive film 117 and the conductive film 123 also have a barrier metal.

The present invention is not limited to wiring, barrier metal, and plugs, but may be applied to electrodes. For example, in the case where the gate electrodes 108 and 109 have a laminated structure of a conductive film and an adjacent film, in order to suppress the diffusion and prevent the occurrence of voids due to migration, the rectangular shape of the free energy minimum surface of the adjacent film is formed. and _{{/ a p | | a p} -a n} × 100 = a (%), the difference between the short sides a _p of rectangular lattice that constitute the short sides a _n lattice free energy minimum surface of the conductive film The difference between the long side b _n of the rectangular lattice forming the minimum free energy surface of the adjacent film and the long side b _p of the rectangular lattice forming the minimum free energy surface of the conductive film {| b _p -b _n | / b _p } × 100 = B (%) is
It is formed by a combination of materials that satisfy the inequality of {A + B × (a _p / b _p )} <13%. Specifically, for example, when a copper (Cu) film is used as the conductive film, the adjacent film is rhodium (Rh).
Film, ruthenium (Ru) film, iridium (Ir) film, osmium
One kind of film selected from the group consisting of (Os) film and platinum (Pt) film is used. When a platinum (Pt) film is used as the conductive film, adjacent films include a rhodium (Rh) film and a ruthenium (Ru) film.
One kind of film selected from the group consisting of a film, an iridium (Ir) film, and an osmium (Os) film is used. In addition, the gate electrode 10
There may be another film such as titanium nitride between 8, 109 and the gate insulating films 106, 107.

In the above, when a copper (Cu) film is used as the conductive film, in order to suppress diffusion, the adjacent film is
Rhodium (Rh) film, Ruthenium (Ru) film, Iridium (Ir)
Although one type of film selected from the group consisting of a film, an osmium (Os) film, and a platinum (Pt) film has been used, the ruthenium (Ru) film is an adjacent film considering that it has a high melting point and is easy to process. Can be said to be the most preferable.

Among the third embodiments, a functionally particularly preferable structure will be described with reference to FIG. The structural difference from FIG. 8 is that the adjacent film 1 is provided between the adjacent film 116a and the insulating film 113.
26a is formed, the adjacent film 116b and the insulating film 121 are formed.
The adjacent film 126b is formed between the adjacent films and the adjacent film 122a.
The adjacent film 127a is formed between the insulating film 121 and the insulating film 121, and the adjacent film 127b is formed between the adjacent film 122b and the insulating film 121.
Is formed. Conductive film 11 to be wiring
Nos. 7 and 123 are made of a copper (Cu) film having a low electric resistance in order to improve the speed of the device. And in order to make the migration resistance of this copper (Cu) film wiring excellent,
Adjacent films 116a, 116b, 122a, 122b as barrier metals of the copper (Cu) films 117, 123 are made of ruthenium (Ru).
It consists of a membrane. The plugs 115 and 120 adjacent to the copper (Cu) films 117 and 123 are made of a ruthenium (Ru) film in order to have excellent migration resistance. For example, Materials Research Society
siety, abbreviated MRS)
(Symposium Proceedings) Volume 428, Materials Reliability in Microelectronics
Electromigration resistance near the plug is especially important, as described in pages 81-86 of cs). The ruthenium (Ru) plug also has the advantage of good heat resistance. As described above, since both the plug 115 and the barrier metal 116a are made of a ruthenium (Ru) film, it is more preferable to collectively form these films because the manufacturing is simplified. Similarly, the plug 120 and the barrier metal 1
Since 27a is composed of a ruthenium (Ru) film, it is more preferable to collectively form 27a because the manufacturing is simplified. In order to improve the adhesion between the ruthenium (Ru) film and the insulating film, barrier metals 126a, 126b, 1
27a, 127b, 114a, 114b, 119a, 119b
Is a titanium nitride (TiN) film. As a result, both the barrier metals 114a and 114b and the barrier metal 126a are made of a titanium nitride (TiN) film, and it is more preferable to collectively form these films because the manufacturing is simple. Similarly, barrier metal 119a, 119b and barrier metal 12
Since 7a is made of a titanium nitride (TiN) film, it is more preferable to collectively form 7a because the manufacturing is simplified. In the above, at least one of the copper film and the barrier metal is formed by using at least sputtering. It is more preferable that there is a film having a low contact resistance such as a metal silicide film between the barrier metal 114a and the diffusion layer 104.

Although not shown in FIG. 9, a copper (Cu) film 11
In order to prevent copper (Cu) atoms from diffusing into the insulating film from the side walls of 7, 123, the copper (Cu) film 117 and the copper (Cu) film 123
It is preferable to form a barrier metal also on the side wall of the.

The computer simulation results shown in FIGS. 2, 3, 4, and 5 are the results obtained by the molecular dynamics simulation. A molecular dynamics simulation is, for example, the Journal of Applied Physics.
f Applied Physics) Volume 54 (1983) 48
As described on pages 64 to 4878, the force acting on each atom through the interatomic potential is calculated, and the position of each atom at each time is calculated by solving Newton's equation of motion based on this force. Is the way. Also, regarding the method of calculating the diffusion coefficient by molecular dynamics simulation, for example, Volume 29 of Physical Review B (published in 1984).
Pp. 5363 to 5371. Further, it is well known that the electromigration resistance is improved when the diffusion of copper (Cu) is suppressed, and for example, a symposium proceedings of Materials Research Society (MRS for short) ( Symposium Proceedings) 4
Materials Reliability in Microelectronics (Vol. 28)
(bility in Microelectronics), pages 43-60. As mentioned above, FIGS.
Nos. 4 and 5 are the results of the simulation at the temperature of 700 K, but the effects shown here can be shown even when the simulation conditions such as the temperature are changed.

Further, FIG. 6 shows a rectangular lattice constituting a crystal plane having the minimum free energy in a bulk crystal, and the definition of the short side a and the long side b of the rectangular lattice is shown below. Will be explained in more detail. The short side a is the closest interatomic distance in a bulk crystal, for example,
Introduction to Solid State Physics, First Volume, 5th Edition (by Charles Kittel, 1
(Published by Maruzen Co., Ltd. in 978) on page 28. The long side b is about 1.73 times the short side a for a crystal having a face-centered cubic structure or a close-packed hexagonal structure, and about 1.41 times the short side a for a crystal having a body-centered cubic structure. For example, the minimum free energy plane of copper (Cu) having a face-centered cubic structure is the (111) plane, and its short side a _Cu is about 0.26 nm,
The long side b _Cu is about 0.44 nm. The minimum free energy plane of ruthenium (Ru) having a close-packed hexagonal structure is the (001) plane, and its short side a _Ru is about 0.27 nm and its long side b _Ru is about 0.46 nm.

Based on the results of the present invention, the inventors conducted a prior art search. As a result, the inventors have found Japanese Patent Laid-Open No. 10-229084 as related to copper (Cu) wiring and its barrier metal. However, this is distinct from the present invention, as described below. JP 10-2290
Japanese Patent Publication No. 84 has a problem of facilitating formation of a barrier metal and a copper (Cu) film wiring in a connection hole having a high aspect ratio, so that both the barrier metal and the copper (Cu) film wiring are subjected to physical vapor deposition such as sputtering ( The target is a wiring structure formed by plating or chemical vapor deposition (CVD) without using PVD). On the other hand, the present invention is directed to a wiring structure in which at least one of the barrier metal and the copper (Cu) film wiring is formed by using physical vapor deposition, as in the normal wiring structure. Then, it is an object to improve electromigration resistance, which is particularly important when using physical vapor deposition. Normal barrier metal and copper (Cu)
In forming the film wiring, at least one of the barrier metal and the copper (Cu) film wiring is formed by using physical vapor deposition such as sputtering, for example, monthly Semiconductor World (published by Press Journal, Inc., 199
February 1998 issue, pages 91-96). As described therein, when the copper (Cu) film wiring is formed by plating or chemical vapor deposition (CVD), copper (Cu) is usually first deposited by physical vapor deposition (PVD) such as sputtering. The method is to form a seed layer of the film and then switch to plating or chemical vapor deposition (CVD). Therefore, JP-A-10
As in Japanese Patent No. 229084, forming both the barrier metal and the copper (Cu) film wiring by using plating or chemical vapor deposition (CVD) without using physical vapor deposition (PVD) such as sputtering, It is preferable for achieving the purpose of forming a connection hole having a high aspect ratio, but it is rarely performed at present. As a reason why it is hardly done at present, it is formed by physical vapor deposition (PVD) as described in, for example, Monthly Semiconductor World (published by Press Journal, Inc., February 1998, pages 86-96). The seed layer of the copper (Cu) film is superior in adhesiveness to the seed layer of the copper (Cu) film formed by chemical vapor deposition (CVD), and the copper (Cu) film is formed by plating. It is almost impossible to form directly on the barrier metal, and the barrier metal formed by chemical vapor deposition (CVD) has the drawback of either high resistance or low barrier. To be
The most commonly used sputtering among physical vapor deposition (PVD) is, for example, a thin film handbook (published by Ohmsha,
As described on pages 171 to 195 (edited by the Japan Society for the Promotion of Science), rare gas elements such as argon (Ar), xenon (Xe), krypton (Kr), and neon (Ne) (also called noble gas elements). ) Is used, the rare gas element is 0.0
001% or more will be included, but plating and chemical vapor deposition
It can be said that it is preferable because it has better adhesion than a film formed by (CVD).

The barrier metal here is originally
It has the meaning of a barrier metal for preventing the diffusion of wiring materials such as copper (Cu), and for example, copper (C
u) The adjacent films 116a and 116b in the case of using the film are called barrier metal. The barrier metal may have a role of improving the adhesion, a role of controlling the crystal orientation, a role of controlling the size of the crystal grain, and the main role may not be diffusion prevention. In the present specification, even when the adjacent films 116a, 1a are used for purposes other than diffusion prevention,
Conductive films such as 16b, 114a and 114b used adjacent to the conductive film are described as barrier metal.

What is called a copper (Cu) film is a film whose main constituent element is copper (Cu), and even if it contains other elements, the same effect as above is obtained. Can be shown. The same applies to ruthenium (Ru) films and the like.

[0031]

According to the present invention, it is possible to suppress the diffusion of a conductive film in a semiconductor device having a laminated wiring structure in which a conductive film is formed on a semiconductor substrate in contact with the conductive film and adjacent films are stacked. it can. Therefore, it is possible to provide a highly reliable semiconductor device which is unlikely to cause voids or disconnection in the laminated wiring structure.

[Brief description of drawings]

FIG. 1 is a sectional view of a laminated wiring structure of a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an effect of an adjacent film material on a diffusion coefficient when a copper (Cu) film is a conductive film.

FIG. 3 is a characteristic diagram showing the effect of an adjacent film material on the diffusion coefficient when a copper (Cu) film is used as a conductive film, along the broken line in FIG.

FIG. 4 is a characteristic diagram showing an effect of an adjacent film material on a diffusion coefficient when a platinum (Pt) film is a conductive film.

5 is a characteristic diagram showing the effect of an adjacent film material on the diffusion coefficient when a platinum (Pt) film is used as a conductive film, along the broken line in FIG.

FIG. 6 is a diagram showing an atomic arrangement and a short side and a long side in a rectangular lattice.

FIG. 7 is a sectional view of a laminated wiring structure of a semiconductor device according to a second embodiment of the present invention.

FIG. 8 is a sectional view of a main portion of a semiconductor device according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view of a main portion of a semiconductor device having a functionally particularly preferable structure among the semiconductor devices according to the third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... Insulating film, 3 ... Adjacent film, 4 ... Conductive film, 5 ... Adjacent film, 6 ... First laminated wiring structure, 7 ... Insulating film, 8 ... Via, 9 ... Adjacent film, 10 ... Conductive film, 11 ... Adjacent film, 12 ... Second laminated wiring structure, 13, 14, 15, 1
6 ... Diffusion prevention film, 101 ... Silicon substrate, 102, 10
3, 104, 105 ... Diffusion layer, 106, 107, ... Gate insulating film, 108, 109, 110 ... Element isolation film, 11
1, 112, 113, 118, 121, 124, 125
... Insulating films, 114a, 114b, 116a, 116b,
119a, 119b, 122a, 122b, 126a,
126b, 127a, 127b ... Adjacent film, 115, 11
7, 120, 123 ... Conductive film.

─────────────────────────────────────────────────── --- Continuation of front page (56) References JP-A-6-236878 (JP, A) JP-A-10-256251 (JP, A) JP-A-5-315336 (JP, A) JP-A-9- 69522 (JP, A) JP 10-284601 (JP, A) JP 10-22274 (JP, A) Special Table 2001-505367 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) H01L 21/768 H01L 21/28 301 H01L 21/3205

Claims (6)

(57) [Claims] 1. A copper (C) formed on a main surface side of a semiconductor substrate.
u) In a semiconductor device having a structure having a film wiring, a barrier metal formed in contact with the copper (Cu) film wiring, and a plug formed in contact with the barrier metal, the barrier metal is ruthenium (Ru ) Film, the plug is a ruthenium (Ru) film, at least one of the copper (Cu) film wiring and the plug contains a layer formed using physical vapor deposition (PVD) Characteristic semiconductor device. 2. A copper (C) formed on one main surface side of a semiconductor substrate.
u) the film wiring, the first barrier metal formed in contact with the copper (Cu) film wiring, the plug formed in contact with the first barrier metal, the plug and the first barrier metal In a semiconductor device having a structure having a formed second barrier metal, the first barrier metal is a ruthenium (Ru) film, the plug is a ruthenium (Ru) film, the second barrier metal is titanium nitride (TiN ) Film, and at least one of the copper (Cu) film wiring and the first barrier metal is a film formed by sputtering. 3. Copper formed on one main surface side of a semiconductor substrate (C
u) Membrane wiring and the copper (Cu) Burrs formed in contact with the film wiring
Yametal and a plastic formed in contact with the barrier metal
In a method of manufacturing a semiconductor device having a structure having
hand, Forming an insulating film on a semiconductor substrate;
Forming the plug on the The barrier metal contacting the plug on the insulating film
And a step of forming the copper film wiring provided with The barrier metal is ruthenium (Ru) The membrane and the plastic
Ruthenium (Ru) A membrane, The copper (Cu) At least one of the membrane wiring and the plug has an object
Physical vapor deposition (PVD) Includes layers formed using
A method for manufacturing a semiconductor device, comprising: 4. Copper formed on the one main surface side of a semiconductor substrate (C
u) Membrane wiring and the copper (Cu) First formed in contact with membrane wiring
The barrier metal is formed in contact with the first barrier metal.
The plug and the plug and the first barrier metal
A structure having a second barrier metal formed in contact with
In the method of manufacturing a semiconductor device provided with, Forming an insulating film on a semiconductor substrate;
Forming the plug on the The first barrier in contact with the plug on the insulating film
The copper film wiring including a metal and the second barrier metal
And a step of forming The first barrier metal is ruthenium (Ru) A membrane and said
Ruthenium plug (Ru) A membrane, said second barrier metal
Is titanium nitride (TiN) The film is copper (Cu) Membrane wiring and front
At least one of the first barrier metals is sputtered
A semiconductor device characterized by being a film formed by using
Manufacturing method. 5. A copper (C) formed on the main surface side of a semiconductor substrate.
u) In a semiconductor device having a structure having a film wiring, a barrier metal formed in contact with the copper (Cu) film wiring, and a plug formed in electrical contact with the barrier metal, the barrier metal is ruthenium (Ru) film, said plug and wherein a Ru ruthenium (Ru) Makudea. 6. A copper (C) formed on one main surface side of a semiconductor substrate.
u) film wiring, a first barrier metal formed in contact with the copper (Cu) film wiring, a plug formed in electrical contact with the first barrier metal, and the plug and the first barrier metal In a semiconductor device having a structure having a second barrier metal formed in contact with each other, the first barrier metal is a ruthenium (Ru) film, the plug is a ruthenium (Ru) film, and the second barrier metal is nitrided. Titanium (T
wherein a iN) Makudea Ru.