JPH11317455A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly reliable semiconductor device, in which voids and disconnection are hard to occur by forming a barrier metal which is formed in contact with copper-film wiring of a ruthenium film and copper wiring in a laminated structure of a sputtered copper film and a plate copper film. SOLUTION: In a laminated structure 6 composed of a conductive film 4 and an adjacent film 5 laminated upon the film 4 cove in contact with the film 4, the materials of the films 4 and 5 are selected so that the difference, |ap -an |/ap }×100=A (%), between the short side ap of the rectangular lattice constituting the minimum free energy surface of the conductive film 4 and the short side an of the rectangular lattice constituting the minimum free energy surface of the adjacent film 5, and the difference between |bp -bn |/bp }×100=B (%) between the long side bp of the rectangular lattice constituting the minimum free energy surface of the film 4 and the long side bn of the rectangular lattice constituting the minimum free energy surface of the film 5 satisfies the inequality, A+B(ap /bp )<13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device,
In particular, the present invention relates to a semiconductor device having a wiring structure having a stacked wiring structure.

[0002]

2. Description of the Related Art With the recent increase in the degree of integration and speed of semiconductor devices, copper (Cu) wiring having lower electric resistance than conventional aluminum (Al) wiring is being introduced. However, copper (C
u) If the atoms diffuse into the silicon (Si) substrate or insulating film, device characteristics may be degraded, and a diffusion prevention film for preventing the diffusion of copper (Cu) atoms is adjacent to the copper (Cu) film. It is formed. As described in Nikkei Micro Devices (June 1992, pp. 74-77), a material such as titanium nitride (TiN) film, tungsten (W) film, tantalum (Ta) film, etc. Melting point metal films are being considered.

[0003]

Since a high-density current flows in a semiconductor device miniaturized for high integration, atoms are diffused by the flow of electrons and the heat generated thereby, and voids and disconnections are caused. There is a problem of so-called electromigration that occurs. The copper (Cu) film has a higher melting point than the aluminum (Al) film, so that it hardly causes diffusion and is expected to have excellent electromigration resistance. However, titanium nitride (T
iN) film, tungsten (W) film, tantalum (Ta) film, etc.
u) The layered wiring structure in contact with the film has a problem that sufficient electromigration resistance cannot be obtained and 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 less likely to occur in a 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 preventing film. In, it is clear that the atomic arrangement at the interface is disturbed because the lengths of the sides of the diffusion barrier film material and the unit crystal lattice of copper (Cu) are significantly different, and voids and disconnections are likely to occur due to active diffusion. I made it. Therefore, in order to prevent voids and disconnection of the copper (Cu) wiring, diffusion may be suppressed by using a material having a small difference in the length of the sides of the unit crystal lattice between the copper (Cu) and the adjacent film. . In a stacked wiring structure in which a conductive film and an adjacent film are stacked in contact with the conductive film, a short side a _p of a _rectangular lattice forming a free energy minimum surface of the conductive film is defined by the inventors. the difference of the short sides a _n of rectangular lattice that constitute the minimum free energy surfaces of adjacent film _{{| a p -a n | /} a p} × 100 = a
(%) Is less than 13%, yet the long sides of the rectangular lattice that constitute the minimum free energy surface of the adjacent layer with the long side b _p of rectangular lattice that constitute the minimum free energy surface of the conductive film
When the difference of b _n {| b _p -b _n | / b _p } × 100 = B (%) multiplied by (a _p / b _p ) is less than 13, diffusion of the conductive film is suppressed. ,
Clarified that voids and disconnections are suppressed. Also,
In particular, it has been clarified that it is more preferable that A and B satisfy the inequality {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 as shown in FIG.

SUMMARY OF THE INVENTION Accordingly, 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 on and in contact with the conductive film on a semiconductor substrate. The short side a _p of the rectangular lattice
Free energy minimum of _{{/ a p | | a p} -a n} × 100 = A (%) and the conductive film wherein the difference of the short side a _n of rectangular lattice that constitute the minimum free energy surfaces of adjacent film and 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
+ B × (a _p / b _p )} <13 is achieved by selecting the materials of the conductive film and the adjacent film so as to satisfy the inequality:

Another object of the present invention is to provide copper (C) on a semiconductor substrate.
u) a semiconductor device having a laminated wiring structure in which a film and an adjacent film are stacked in contact with the copper (Cu) film;
(Rh) film, ruthenium (Ru) film, iridium (Ir) film, osmium (Os) film or platinum (Pt) film.

Another object of the present invention is to provide a semiconductor substrate comprising platinum.
In a semiconductor device having a stacked wiring structure in which an adjacent film is stacked in contact with the (Pt) film and the platinum (Pt) film, the adjacent film is formed of a rhodium (Rh) film, a ruthenium (Ru) film, and an iridium (Ir) film. Alternatively, it is achieved by using an osmium (Os) film.

Specifically, it is desirable to adopt 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. (Ru) film, wherein 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 copper (Cu) formed using chemical vapor deposition (CVD) Having a laminated structure with a film. 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 formed by sputtering. Ruthenium formed using
(Ru) film, the copper (Cu) film wiring is formed by sputtering copper (Cu) film and plating or chemical vapor deposition
It has a laminated structure with a copper (Cu) film formed by 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 formed of 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 having, the barrier metal is a ruthenium (Ru) film, the plug is a ruthenium (Ru) film, and at least one of the copper (Cu) film wiring and the plug is formed by physical vapor deposition (PVD). Include layers formed using. Copper (C) formed on one principal surface side of the semiconductor substrate
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 in contact with the plug and the first barrier metal. In a semiconductor device having a structure having a second barrier metal formed, the first barrier metal is a ruthenium (Ru) film, and the plug is ruthenium (Ru).
Wherein 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 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 (Os) a film selected from the group consisting of films, and at least one of the platinum (Pt) electrode film and the adjacent film is a film formed by sputtering. The method of manufacturing a semiconductor device includes the following steps.

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

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

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

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a cross-sectional structure of a laminated wiring structure 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 the present 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 made up of 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. I have. 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.
A via 8 made of (W) is formed. Through this via, a second laminated wiring structure 12 composed of an adjacent film 9, a conductive film 10, and an adjacent film 11 is connected. Here, regarding the first laminated wiring structure 6, the short side a _p of the rectangular lattice forming the minimum free energy plane of the conductive film 4 and the rectangular lattice forming the minimum free energy plane of the adjacent films 3 and 5 are formed. Difference of short side a _n {| a _p -a _n |
_{/ a p} × 100 = A} (%) and said rectangular lattice that constitute the minimum free energy surface of the conductive film 4 long side b _p and the neighboring films 3 and 5
The difference in the rectangular lattice that constitute the minimum free energy surface of the long sides _{b n {| 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 satisfying the following inequality. Specifically, when a copper (Cu) film is used as the conductive film 4, the adjacent films 3 and 5 include 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, the adjacent films 3, 5 are rhodium (Rh), ruthenium (Ru), iridium (Ir), or osmium (O).
s) A film may be used.

Similarly, the second laminated wiring structure 12 also forms the short side a _p of the rectangular lattice forming the free energy minimum plane of the conductive film 10 and the free energy minimum plane of the adjacent films 9 and 11. the difference of the short sides a _n of a rectangular lattice _{{| a p -a n | /} a p} ×
100 = A (%) and the long side b of rectangular lattice that constitute the minimum free energy surface of the long sides b _p and the neighboring layer 9, 11 of the rectangular lattice that constitute the minimum free energy surface of the conductive film 10 _n difference
{| B _p -b _n | / b _p } × 100 = B (%) is a combination of materials satisfying the inequality of {A + B × (a _p / b _p )} <13. And 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, and osmium (Os) film. Alternatively, a platinum (Pt) film may be used. When a platinum (Pt) film is used as the conductive film 10, a rhodium (Rh) film, a ruthenium (Ru) film, an iridium (Ir) film or an osmium (Os) film is used as the adjacent films 9 and 11. Good.

Hereinafter, effects of the semiconductor device of the present embodiment will be described. The authors focused on the difference between the conductive film and the adjacent film on the short side a and long side b of the rectangular lattice forming the minimum free energy plane, and examined the effect of this difference on the diffusion coefficient by computer simulation. Was. Specifically, in a laminated wiring structure in which a conductive film and an adjacent film are stacked in contact with the conductive film, a short side a _p of a _rectangular lattice forming a free energy minimum surface of the conductive film and the the difference of the short sides a _n of rectangular lattice that constitute the minimum free energy surfaces of adjacent film _{{| a p -a n | /} a p} ×
100 = A (%) of horizontal axis, the long side b of rectangular lattice that constitute the minimum free energy surface of the adjacent layer with the long side b _p of rectangular lattice that constitute the minimum free energy surface of the conductive film _n difference
{| B _p -b _n | / b _p } × 100 = Create a map with the vertical axis representing the amount obtained by multiplying B (%) by (a _p / b _p ). And B were set, and the value of the diffusion coefficient in the conductive film was calculated by computer simulation.

First, a simulation was conducted 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. FIG. 2 shows a simulation result in this case. A result was obtained in which the diffusion coefficient of the copper (Cu) film rapidly increased 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 are unlikely to occur, and the region outside the boundary is a region where the diffusion coefficient is large and voids and the like are likely to occur. FIG. 3 shows the result of examining the diffusion coefficient of the copper (Cu) film along the broken line in FIG. 2 to see this state in detail. Where D is the diffusion coefficient of the copper (Cu) film, and D ₀ is the bulk copper (C
This is the diffusion coefficient in u). It can be seen that the diffusion coefficient sharply increases at the boundary, and titanium nitride (TiN), etc., which has been conventionally used as an adjacent film, is located ahead of the diffusion coefficient. FIG. 2 shows that the tungsten (W) film and the tantalum (Ta) film are also outside the boundary. On the other hand, inside the boundary of FIG.
That is, rhodium (Rh) film, ruthenium (Ru) film,
The iridium (Ir) film, the osmium (Os) film, and the platinum (Pt) film are located, and it is understood that these are effective in suppressing the diffusion of the copper (Cu) film. These materials have both A and B × (a _p / b _p ) of 1
It is in the area of less than 3%. When the boundary line in Fig. 2 is approximated by a straight line, {A
+ B × (a _p / b _p )} = 13. Therefore, {A + B × (a _p /
When the conductive film and the adjacent film are formed by a combination of materials satisfying the inequality of b _p )} <13, diffusion is suppressed, and voids and disconnection are suppressed. Here, attention was paid to the diffusion coefficient of the copper (Cu) film, and it was determined that the smaller the diffusion coefficient, the less the occurrence of voids and the like in the copper (Cu) film. It is more preferable that the adjacent film be 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.), and osmium (melting point 3045 ° C.) are more preferred.

Next, a simulation was performed using platinum (Pt) as the conductive film. Platinum (Pt) is also a face-centered cubic lattice, and the minimum free energy plane is the (111) plane. The simulation results in this case are shown in FIGS. The result of FIG. 4 is the same as that of FIG. 2; the area inside the boundary, that is, the area from the origin is an area where the diffusion coefficient is small and voids are unlikely to occur, and the area outside the boundary is the area where the diffusion coefficient is small. This is a region where voids and the like are likely to occur. FIG. 5 shows the result of examining the diffusion coefficient of the platinum (Pt) film along the broken line in FIG. 4 to see this state in detail. In FIG. 5, D is platinum (P
t) 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 (Rh) is inside the boundary of Fig. 4.
Film, ruthenium (Ru) film, iridium (Ir) film, osmium (O
s) The film is located, indicating that these materials are effective in suppressing the diffusion of the platinum (Pt) film. These materials have both A and B × (a _p / b _p ) in the region of less than 13%. It can be seen that the position of the boundary line in FIG. 4 matches well with the case of the copper (Cu) film. When these boundaries are approximated by a straight line, {A + B × (a _p / b
_p )} = 13. Therefore, when the conductive film and the adjacent film are formed by a combination of materials satisfying the inequality {A + B × (a _p / b _p )} <13, diffusion is suppressed, and voids and disconnection 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 the present 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
Anti-diffusion film 1 through contact holes formed in
3, adjacent film 3, conductive film 4, adjacent film 5, diffusion prevention film 14
Is connected. 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. Through this via, the second laminated wiring structure 12 composed of 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. Here, the diffusion prevention films 13, 14, 15, 16 are made of, for example, titanium nitride (TiN), tungsten (W), or tantalum (Ta). For the first stacked wiring structure 6, the short side a _p of the rectangular lattice forming the minimum free energy plane of the conductive film 4 and the short side a of the rectangular lattice forming the minimum free energy plane of the adjacent films 3, 5 _n difference {| a _p-
configure _{/ a p} × 100 = A} (%) and the long side b _p a minimum free energy surface of the adjacent films 3 and 5 of the rectangular lattice that constitute the minimum free energy surface of the conductive film 4 | a _n The difference between 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 conductive film 4 and the adjacent film 5 are formed. Specifically, when a copper (Cu) film is used as the conductive film 4, a rhodium (Rh) film, a ruthenium film is used as the adjacent films 3 and 5.
(Ru) film, iridium (Ir) film, osmium (Os) film or platinum
A (Pt) film may be used. Platinum (P) is used as the conductive film 4.
t) When a 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, the second laminated wiring structure 12 also forms the short side a _p of the rectangular lattice forming the minimum free energy plane of the conductive film 10 and the minimum free energy plane of the adjacent films 9 and 11. the difference of the short sides a _n of a rectangular lattice _{{| a p -a n | /} a p} ×
100 = A (%) and the long side b of rectangular lattice that constitute the minimum free energy surface of the long sides b _p and the neighboring layer 9, 11 of the rectangular lattice that constitute the minimum free energy surface of the conductive film 10 _n difference
{| B _p -b _n | / b _p } × 100 = B (%) is a combination of materials satisfying the inequality of {A + B × (a _p / b _p )} <13. And 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, and osmium (Os) film. Alternatively, a platinum (Pt) film may be used. When a platinum (Pt) film is used as the conductive film 10, a rhodium (Rh) film, a ruthenium (Ru) film, an iridium (Ir) film or an osmium (Os) film is used as the adjacent films 9 and 11. Good.

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

In the third embodiment, the adjacent film 11
The conductive film 117 and the adjacent film 12 coated on 6a and 116b
At least one of the conductive films 123 covered with 2a and 122b has at least one short side a of a rectangular lattice forming a free energy minimum plane of an adjacent film in order to suppress diffusion and to prevent generation of voids due to migration. Difference between _n and the short side a _p of the rectangular lattice constituting the free energy minimum plane of the conductive film
{| A _p -a _n | / a _p } × 100 = A (%), the long side b _n of the rectangular lattice constituting the free energy minimum surface of the adjacent film, and the free energy minimum surface of the conductive film Long side of the rectangular lattice
The difference in 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 type of film selected from the group consisting of an osmium (Os) film and a platinum (Pt) film is used. Plug conductive films 115 and 120
Are adjacent to the conductive film 117, so that the conductive films 115, 1
20 can be regarded as a film adjacent to the conductive film 117. Therefore, when a copper (Cu) film is used as the conductive film 117, a rhodium (Rh) film, a ruthenium (Ru) film is used as the conductive films 115 and 120. By using one type of film selected from the group consisting of a film, an iridium (Ir) film, an osmium (Os) film, and a platinum (Pt) film, diffusion of the conductive film 117 is suppressed, and generation of voids due to migration is prevented. I do. In this way, a rhodium (Rh) film, a ruthenium (Ru) film, an iridium (I
r) film, osmium (Os) film, platinum (Pt) film has a higher melting point than copper (Cu) film, so compared to the case where copper (Cu) film is used as the conductive films 115 and 120 of the plug. Also, the effect of improving the heat resistance of the plug is 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 119b because adhesion to 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. In the case where importance is placed on 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 the adjacent films 114a and 114a of the conductive films 115 and 120 are used. 11
Rhodium (Rh) film, ruthenium (Ru) film, iridium (Ir) film, osmium (Os)
One type of film selected from the group consisting of a film and a platinum (Pt) film is used. Also, although not shown in FIG.
16b, 122a, 122b, 114a, 114b, 119
One or more other films may be formed between each of a and 119b and the insulating film as in the case of FIG.

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 the conductive films 117 and 123, it is preferable that the conductive film 117 and the side wall of the conductive film 123 also include 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, a rectangular structure forming the minimum free energy surface of the adjacent film is used in order to suppress diffusion and prevent generation of voids due to migration. 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 difference {long side b _p of rectangular lattice that constitute the minimum free energy surface of the long sides b _n and the conductive film of the rectangular lattice that constitute the minimum free energy surface of the adjacent film | b _p -b _n | / b _p } × 100 = B (%)
It is formed of a combination of materials satisfying the inequality of {A + B × (a _p / b _p )} <13%. Specifically, for example, when using a copper (Cu) film as the conductive film, as the adjacent film, rhodium (Rh)
Film, ruthenium (Ru) film, iridium (Ir) film, osmium
One type of film selected from the group consisting of an (Os) film and a platinum (Pt) film is used. When a platinum (Pt) film is used as the conductive film, a rhodium (Rh) film, a ruthenium (Ru) film is used as an adjacent 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 the gate insulating films 8 and 109 and the gate insulating films 106 and 107.

In the above, when a copper (Cu) film is used as the conductive film, 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 described as being used, the ruthenium (Ru) film is an adjacent film in consideration of its high melting point and easy processing. It can be said that this is the most preferable.

A functionally particularly preferred structure of the third embodiment will be described with reference to FIG. The structural difference from FIG. 8 is that the adjacent film 1a is located between the adjacent film 116a and the insulating film 113.
26a are formed, and the adjacent film 116b and the insulating film 121 are formed.
Adjacent film 126b is formed between adjacent films 122a
An adjacent film 127 a is formed between the insulating film 121 and the adjacent film 127 b between the adjacent film 122 b and the insulating film 121.
Is formed. Conductive film 11 serving as wiring
Reference numerals 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 and 122b as barrier metals of copper (Cu) films 117 and 123 are made of ruthenium (Ru).
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 improve migration resistance. For example, Materials Research So
siety (MRS for short) Symposium Proceedings
(Symposium Proceedings), Volume 428, Materials Reliability in Microelectroni
As described on pages 81 to 86 of cs), the electromigration resistance near the plug is particularly important. Ruthenium (Ru) plugs also have 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, plug 120 and barrier metal 1
Since both 27a are made of a ruthenium (Ru) film, it is more preferable to collectively form these films 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
Consists of a titanium nitride (TiN) film. Thus, since the barrier metals 114a and 114b and the barrier metal 126a are both made of a titanium nitride (TiN) film, it is more preferable to collectively form them so that the manufacturing is simplified. Similarly, barrier metals 119a and 119b and barrier metal 12
7a is made of a titanium nitride (TiN) film, so that it is more preferable to collectively form these films because the manufacturing is simplified. In the above, at least one of the copper film and the barrier metal is formed using at least sputtering. It is more preferable that a film having a low contact resistance such as a metal silicide film is provided between the barrier metal 114a and the diffusion layer 104.

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

The results of the computer simulation shown in FIGS. 2, 3, 4, and 5 are the results obtained by the molecular dynamics simulation. Molecular dynamics simulation refers to, for example, Journal of Applied Physics (Journal
f Applied Physics), Volume 54 (issued in 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. Regarding a method of calculating a diffusion coefficient by molecular dynamics simulation, for example, Physical Review B (Vol. 29, published in 1984)
Pages 5363 to 5371. Furthermore, it is well known that the suppression of diffusion of copper (Cu) improves the electromigration resistance. (Symposium Proceedings) 4
Materials Reliability in Microelectronics, published as Volume 28
abilities in Microelectronics) on pages 43-60. As described above, FIGS.
4 and 5 are the results of the simulation at a temperature of 700 K, but the effects shown here can be shown by changing the simulation conditions such as the temperature.

FIG. 6 shows a rectangular lattice forming a crystal plane having a 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 described in more detail. The short side a is a distance between nearest neighbor atoms in a bulk crystal.
Introduction to Solid State Physics Vol.5 (Charles Kittel, 1
(Issued 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 free energy minimum plane of copper (Cu) having a face-centered cubic structure is a (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, Japanese Patent Application Laid-Open No. 10-229084 was found as a copper (Cu) wiring and its barrier metal. However, this is clearly different from the present invention, as described below. JP 10-2290A
No. 84 is directed to making it easy to form barrier metal and copper (Cu) film wiring in connection holes having a high aspect ratio.Therefore, both barrier metal and copper (Cu) film wiring are formed by physical vapor deposition such as sputtering. It is intended for wiring structures 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 a barrier metal and a copper (Cu) film wiring is formed using physical vapor deposition, as in a normal wiring structure. Another object is to improve electromigration resistance, which is particularly important when using physical vapor deposition. Normal barrier metal and copper (Cu)
In the formation of film wiring, at least one of the barrier metal and copper (Cu) film wiring is formed using physical vapor deposition such as sputtering, for example, monthly Semiconductor World (published by Press Journal Inc., 199
Feb. 8, pp. 91-96). As described therein, when copper (Cu) film wiring is formed by plating or chemical vapor deposition (CVD), copper (Cu) is usually first formed by physical vapor deposition (PVD) such as sputtering. A method of forming a seed layer of the film and then switching to plating or chemical vapor deposition (CVD) is used. Therefore, JP 10
As disclosed in JP-A-229084, it is possible to form both the barrier metal and the copper (Cu) film wiring by plating or chemical vapor deposition (CVD) without using physical vapor deposition (PVD) such as sputtering. Although it is preferable to achieve the purpose of forming a connection hole having a high aspect ratio, it is hardly used at present. The reason why it is rarely used at present is that, as described in, for example, Monthly Semiconductor World (published by Press Journal Inc., February 1998, pages 86 to 96), it was formed by physical vapor deposition (PVD). The seed layer of the copper (Cu) film has better adhesion than the seed layer of the copper (Cu) film formed by chemical vapor deposition (CVD), and the copper (Cu) film is plated by plating. It is almost impossible to form directly on barrier metal, and barrier metal formed by chemical vapor deposition (CVD) has the disadvantage of either high resistance or low barrier property. Can be
The most commonly used sputtering in physical vapor deposition (PVD) is, for example, a thin film handbook (Ohm Company,
As described on pages 171 to 195 of 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) ), The rare gas element in the film is 0.0
More than 001% is included, but plating and chemical vapor deposition
This can be said to be preferable because it has better adhesion than a film formed by (CVD).

[0029] 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). For example, copper (C) is used as the conductive film 117.
u) When the film is used, the adjacent films 116a and 116b are called barrier metal. The barrier metal may have a role of improving adhesion, a role of controlling crystal orientation, a role of controlling crystal grain size, and the like, and the main role may not be diffusion prevention. In this specification, even when the adjacent films 116a, 1a are used for purposes other than diffusion prevention.
A conductive film used adjacent to the conductive film, such as 16b, 114a, 114b, is described as a barrier metal.

Also, what is called a copper (Cu) film is a film in which the main constituent element is copper (Cu). Even if this contains other elements, the same effect as described above can be obtained. Can be shown. The same applies to a ruthenium (Ru) film and the like.

[0031]

According to the present invention, it is possible to suppress diffusion of a conductive film in 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. it can. Therefore, a highly reliable semiconductor device which is less likely to cause voids and disconnections in the stacked wiring structure is provided.

[Brief description of the 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 used as a conductive film.

FIG. 3 is a characteristic diagram showing an effect of an adjacent film material on a diffusion coefficient when a copper (Cu) film is used as a conductive film along a broken line in FIG. 2;

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

5 is a characteristic diagram showing an effect of an adjacent film material on a diffusion coefficient when a platinum (Pt) film is used as a conductive film along a broken line in FIG. 4;

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 part of a semiconductor device according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view of a main part 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 film, 114a, 114b, 116a, 116b,
119a, 119b, 122a, 122b, 126a,
126b, 127a, 127b ... adjacent films, 115, 11
7, 120, 123 ... conductive film.

Claims (8)

[Claims] A copper (C) formed on one principal surface side of a semiconductor substrate
u) film wiring, in a semiconductor device having a laminated structure having a barrier metal formed in contact with the copper (Cu) film wiring, wherein the barrier metal is a ruthenium (Ru) film, the copper (Cu) film Wiring is copper (C
u) A semiconductor device having a laminated structure of a film and a copper (Cu) film formed by plating. 2. Copper (C) formed on one main surface side of a semiconductor substrate.
u) film wiring, in a semiconductor device having a laminated structure having a barrier metal formed in contact with the copper (Cu) film wiring, wherein the barrier metal is a ruthenium (Ru) film, the copper (Cu) film Wiring is copper (C) formed using physical vapor deposition (PVD).
u) Film and copper (Cu) formed using chemical vapor deposition (CVD)
A semiconductor device having a laminated structure with a film. 3. A copper (C) formed on one principal surface side of a semiconductor substrate.
u) film wiring, in a semiconductor device having a laminated structure having a barrier metal formed in contact with the copper (Cu) film wiring, the barrier metal is a ruthenium (Ru) film formed by using sputtering. The copper (Cu) film wiring has a laminated structure of a copper (Cu) film formed using sputtering and a copper (Cu) film formed using plating or chemical vapor deposition (CVD). A semiconductor device. 4. A copper (C) formed on one main surface side of a semiconductor substrate.
u) In a semiconductor device having a structure having a film wiring and a plug formed in contact with the copper (Cu) film wiring, the plug is a rhodium (Rh) film, a ruthenium (Ru) film, an iridium (I
r) film, osmium (Os) film, is a type of film selected from the group consisting of platinum (Pt) film, using physical vapor deposition (PVD) for at least one of the copper (Cu) film wiring and the plug. A semiconductor device comprising a layer formed by: 5. A copper (C) formed on one main surface side of a semiconductor substrate.
u) 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, wherein the barrier metal is ruthenium (Ru ) Film, the plug is a ruthenium (Ru) film, and at least one of the copper (Cu) film wiring and the plug includes a layer formed using physical vapor deposition (PVD). Characteristic semiconductor device. 6. 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 contact with the first barrier metal, and in contact with the plug and the first barrier metal In a semiconductor device having a structure having a second barrier metal formed, the first barrier metal is a ruthenium (Ru) film, the plug is a ruthenium (Ru) film, and the second barrier metal is titanium nitride (TiN). A) a film, wherein at least one of the copper (Cu) film wiring and the first barrier metal is a film formed by using sputtering. 7. Platinum formed on one main surface side of a semiconductor substrate
(Pt) electrode film, 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 and an osmium (Os) film are one type of film selected from the group consisting of films, and at least one of the platinum (Pt) electrode film and the adjacent film is a film formed by using sputtering. A semiconductor device characterized by the above-mentioned. 8. A method for manufacturing a semiconductor device, comprising the following steps. A step of forming a ruthenium (Ru) film on one main surface side of the semiconductor substrate by sputtering; A step of forming a first copper (Cu) film by sputtering so as to be in contact with the ruthenium (Ru) film; A step of forming a second copper (Cu) film by plating or chemical vapor deposition (CVD) so as to be in contact with the first copper (Cu) film;