JP2010177305A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that it is difficult to continuously cover the inner surface of a via hole with a shield layer formed of copper when the via hole is more reduced in size and made higher in aspect ratio. <P>SOLUTION: An insulating film (20) is formed on a semiconductor substrate (10). A concave portion (21) is formed at the insulating film. An inner surface of the concave portion is covered with a first conductive film (22). An insular organization (25) is discretely distributed on a surface of the first conductive film. The insular organization has higher wettability to copper than that of the first conductive film. The concave portion is filled with a conductive member (31) formed of copper or a copper alloy. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a semiconductor device in which a recess formed in an insulating film is filled with a conductive member of copper or copper alloy, and a method for manufacturing the same.

  Since copper used for wiring is more difficult to process than aluminum, which is a conventional wiring material, a damascene method or a dual damascene method is used to form a copper pattern. In the damascene method or the dual damascene method, after forming a copper film filling a recess such as a via hole or a wiring groove formed in an insulating film, a copper pattern is formed by removing an unnecessary copper film. For the formation of the copper film, an electrolytic plating method is generally used from the viewpoint of mass productivity and cost. Before electrolytic plating, a seed layer made of copper used as an electrode is formed by sputtering or the like.

  A method is known in which a recess is filled with a copper member by reflowing a copper film formed on the entire surface of the substrate (Patent Document 1). In order to reflow copper into the recess from the flat surface, a process of making the wettability between the inner surface of the recess and copper higher than the wettability between the flat surface and copper is performed. For example, the surface roughness of the barrier metal film on the inner surface of the recess is made larger than the surface roughness of the barrier metal film on the flat surface. Alternatively, a conductive film made of a material having high wettability with copper is formed only on the inner surface of the recess.

  Also, a method for increasing the surface roughness of a TiN / Ti-based barrier metal film serving as a base when a wiring is formed of an Al-based material is known (Patent Document 2).

Japanese Patent Laid-Open No. 10-209159 Japanese Patent Laid-Open No. 9-223736

  With the high integration and miniaturization of semiconductor integrated circuits, the miniaturization of via holes and the increase in aspect ratio are progressing. As the via hole is miniaturized and the aspect ratio is increased, it becomes difficult to continuously cover the inner surface of the via hole with a seed layer made of copper. For example, the copper adhering to the inner surface of the via hole does not become a flat film, and a plurality of island-like portions distributed discretely are formed. If the island-shaped portions are distributed discretely, they will not function as an electrode for electrolytic plating.

A semiconductor device that solves the above problems is as follows.
An insulating film formed on the semiconductor substrate;
A recess formed in the insulating film;
A first conductive film covering an inner surface of the recess;
An island-like structure made of a conductive material that is discretely distributed on the surface of the first conductive film and has a wettability higher than that of the first conductive film with respect to copper;
And a conductive member made of copper or a copper alloy filling the recess.

A method of manufacturing a semiconductor device that solves the above-described problems is as follows.
Forming a recess in an insulating film formed on a semiconductor substrate;
Covering the inner surface of the recess with a first conductive film;
A step of forming an island structure made of a conductive material that is discretely distributed on the surface of the conductive film and has a wettability higher than that of the first conductive film with respect to copper;
Filling the recess with a conductive member made of copper or a copper alloy.

Another method for manufacturing a semiconductor device that solves the above problems is as follows.
Forming a recess in an insulating film formed on a semiconductor substrate;
Covering the inner surface of the recess with a first conductive film;
Covering the surface of the conductive film with a second conductive film made of a conductive material having higher wettability with respect to copper than the wettability of the first conductive film with respect to copper;
Roughening the surface of the second conductive film;
And after the surface of the second conductive film is roughened, the recess is filled with a conductive member made of copper or a copper alloy.

  The wettability of the base surface on which copper or copper alloy is deposited is increased, and the recess can be stably filled with copper or copper alloy.

FIG. 6 is a cross-sectional view (part 1) of the device in the middle of manufacturing of the semiconductor device manufacturing method according to the first embodiment; FIG. 4 is a sectional view (No. 2) of the device in the middle of manufacturing of the method of manufacturing a semiconductor device according to Example 1; FIG. 6 is a sectional view (No. 3) of the device in the middle of manufacturing of the method of manufacturing a semiconductor device according to Example 1; FIG. 7 is a sectional view (No. 4) of the device in the middle of manufacturing of the method of manufacturing a semiconductor device according to Example 1; (2A) is a perspective view of an island-shaped portion, and (2B) is the coverage of the island-shaped structure, the exposed surface area of the first conductive film, and the exposed surface area of the island-shaped structure. It is a chart which shows the relationship. (3A) is a diagram showing droplets on the substrate and the interfacial tension acting on them, and (3B) and (3C) are droplets on a flat surface and a rough surface when the contact angle is less than 90 °, respectively. (3D) and (3E) are cross-sectional views of droplets on a flat surface and a rough surface when the contact angle is larger than 90 °, respectively. (4A) to (4C) are photographs showing the results of evaluation tests for peeling the copper film on Ta, Ti, and Co, respectively. FIG. 6 is a cross-sectional view (part 1) of a device in the middle of manufacturing of a semiconductor device manufacturing method according to a second embodiment; FIG. 12 is a sectional view (No. 2) of the device in the middle of manufacturing of the method of manufacturing a semiconductor device according to Example 2; FIG. 13 is a sectional view (No. 3) of the device in the middle of manufacturing of the method of manufacturing a semiconductor device according to Example 2;

  Example 1 and Example 2 will be described with reference to the drawings.

  With reference to FIGS. 1A to 1I, a method of manufacturing a semiconductor device according to the first embodiment will be described.

  As shown in FIG. 1A, an element isolation insulating film 11 is formed on the surface layer portion of a semiconductor substrate 10 such as silicon by shallow trench isolation (STI) or the like. An active region surrounded by the element isolation insulating film 11 is defined. A MOSFET 12 is formed in the active region.

  An interlayer insulating film 15 made of silicon oxide or the like is formed on the semiconductor substrate 10 so as to cover the MOSFET 12. By forming a plurality of via holes in the interlayer insulating film 15 and filling the via holes with tungsten (W) or the like, the conductive plugs 16 are formed. The diameter of the via hole is, for example, about 50 nm. The conductive plugs 16 are connected to the source and drain of the MOSFET 12, respectively.

  As shown in FIG. 1B, a second interlayer insulating film 20 is formed on the interlayer insulating film 15. For the interlayer insulating film 20, a so-called Low-k material such as porous silica is used. The interlayer insulating film 20 is formed by, for example, a coating method.

  As shown in FIG. 1C, a plurality of recesses 21 are formed in the interlayer insulating film 20. The upper end of the conductive plug 16 is exposed on the bottom surface of the recess 21. In the following FIGS. 1D to 1H, enlarged sectional views of one recess 21 are shown.

  As shown in FIG. 1D, a first conductive film 22 is formed so as to cover the upper surface of the interlayer insulating film 20 and the inner surface of the recess 21. The first conductive film 22 functions as a barrier metal film that prevents diffusion of copper filling the recess 21. For example, Ta is used for the first conductive film 22. For forming the Ta film, for example, DC sputtering, chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like can be used.

The film formation conditions when the Ta film is formed by DC sputtering are, for example, as follows.
・ DC power 25kW
・ Sputtering gas Ar
・ Pressure 0.1Pa
・ Film thickness 5nm
The film formation conditions when the Ta film is formed by CVD are, for example, as follows.
・ Raw material Pentakisdimethylamino tantalum (PDMAT)
・ Raw material temperature 80 ℃
・ Carrier gas H ₂
・ Flow rate 200sccm
-Substrate temperature 150 ° C to 350 ° C (typically 270 ° C)
・ Pressure 100Pa
・ Film thickness 2nm-10nm (typically 5nm)
In the case of forming a Ta film by ALD, a step of supplying a carrier gas containing a source gas at a flow rate of 100 sccm for 1 second and a step of supplying only a carrier gas at a flow rate of 100 sccm for 1 second are alternately performed for 10 cycles. repeat. The film forming conditions are, for example, as follows.
・ Raw material Pentakisdimethylamino tantalum (PDMAT)
・ Raw material temperature 80 ℃
・ Carrier gas H ₂
-Substrate temperature 100 ° C to 300 ° C (typically 240 ° C)
・ Pressure 100Pa
・ Film thickness 3nm
As Ta raw materials, instead of PDMAT, Cp ₂ TaH ₃ , Ta (OC ₂ H ₅ ) ₅ , Ta (i-OC ₃ H ₇ ) ₅ , Ta (OCH ₃ ) ₅ , tantalum halide (TaCl ₅ , TaF ₅ , TaBr ₅ , TaI ₅ ), Ta [NC (CH ₃ ) ₂ C ₂ H ₅ ] [N (CH ₃ ) ₂ ] _3, or the like can also be used.

  In addition to Ta, another material having a function as a barrier metal may be used for the first conductive film 22. For example, a metal, alloy, nitride, or the like containing Ta, W, Mo, Ti, or Zr can be used.

  As shown in FIG. 1E, an island-like structure 25 made of a conductive material that is discretely distributed is formed on the surface of the first conductive film 22. For the island-like structure 25, a conductive material having wettability higher than that of the first conductive film 22 is used for copper. Wettability can be evaluated by measuring the contact angle of molten copper deposited on a flat surface. Specifically, the contact angle when the molten copper is deposited on the flat surface where the conductive material of the island-like structure 25 is exposed is melted on the flat surface where the material of the first conductive film 22 is exposed. Smaller than the contact angle when copper is deposited.

  For the island structure 25, for example, Co is used. The Co film can be formed by, for example, CVD or an alternate supply method.

The growth conditions for forming the Co island structure by CVD are, for example, as follows.
・ Raw material Dicobalt Hexacarbonyl t-butylacetylene (CCTBA)
・ Raw material container temperature 60 ℃
・ Carrier gas H ₂
・ Board temperature 220 ℃
・ Pressure 100Pa
When Co is grown under these conditions, nucleation occurs on the surface of the first conductive film 22, and then nuclei grow. As the nuclei grow, the nuclei are connected to form a film. When the island-like structure 25 is formed, the growth is stopped before the nuclei are connected. That is, the growth is stopped during the incubation time.

  Under the above-described conditions, an island-like structure 25 having a coverage of about 50% on the surface of the first conductive film 22 is formed. Each of the particles constituting the island-like structure 25 is substantially hemispherical, and its height is 2 nm or less.

When forming an island structure of Co by the alternate supply method, the supply of the source gas, the purge of the source gas, the supply of ammonia (NH ₃ ) gas, and the purge of ammonia gas are repeated in this order for 12 cycles. When supplying the source gas, the gas flow rate is set to 250 sccm, and the supply time is set to 0.5 seconds. When supplying ammonia gas, the gas flow rate is set to 200 sccm, and the supply time is set to 1 second. When supplying the purge gas, the flow rate is 200 sccm, and the supply time is 1 second. The growth conditions are, for example, as follows.
・ Raw material Dicobalt Hexacarbonyl t-butylacetylene (CCTBA)
・ Raw material container temperature 60 ℃
・ Carrier gas Ar
・ Purge gas H ₂
・ Board temperature 220 ℃
・ Pressure 100Pa
Under the above-described conditions, an island-like structure 25 having a coverage of about 50% on the surface of the first conductive film 22 is formed. When the alternate supply method is employed, each particle constituting the island-like structure 25 can be made finer than when CVD is employed. Instead of ammonia gas, other reducing gas may be used.

  As shown in FIG. 1F, a seed layer 30 made of copper is formed, for example, by sputtering on the substrate on which the island-like structure 25 is formed. The seed layer 30 is formed so that the thickness on the flat surface is 20 to 50 nm. At this time, the thickness of the seed layer 30 is 2 to 3 nm on the inner surface of the recess 21. If the seed layer 30 is formed directly on the first conductive film 22 made of Ta without forming the island-like structure 25, the inner surface of the recess 21 does not form a continuous film, and the copper particles are discrete. Resulting in a distributed structure. In this embodiment, since the island-like structure 25 having high wettability with respect to copper is formed, even if the thickness of the seed layer 30 on the inner surface of the recess 21 is 2 to 3 nm, a continuous film is obtained.

  As shown in FIG. 1G, a wiring film 31 is formed by electrolytically plating copper or a copper alloy on the seed layer 30 as an electrode. The recess 21 is filled with the wiring film 31. The first conductive film 22, the island-like structure 25, the seed layer 30, and the wiring film 31 deposited above the upper surface of the interlayer insulating film 22 are removed by chemical mechanical polishing (CMP).

  As shown in FIG. 1H, the wiring 31 a made of copper or a copper alloy remains in the recess 21. Further, the inner surface of the recess 21 is still covered with the first conductive film 22, and the island-like structure 25 is distributed on the surface of the first conductive film 22. The island-like structure 25 is covered with the seed layer 30. Since both the seed layer 30 and the wiring 31a are formed of copper or a copper alloy, it is difficult to clearly distinguish them from each other. Therefore, a structure in which the island-like structure 25 is arranged at the interface between the copper member including the seed layer 30 and the wiring 31a and the first conductive film 22 functioning as a barrier metal film is obtained.

  As shown in FIG. 1I, the wiring 31a is connected to the source and drain of the MOSFET 12 via, for example, the conductive plug 16, respectively.

  Next, with reference to FIG. 2A, FIG. 2B, and FIGS. 3A-3E, the effect of the island-like structure 25 and a preferable coverage will be described.

  FIG. 2A shows a schematic perspective view of one island-like portion 25 </ b> A constituting the island-like tissue 25. Each shape of the island-like portion 25A is substantially hemispherical. Assuming that the area of the bottom surface of the hemispherical island-shaped portion 25A is S, the area of the spherical curved surface of the island-shaped portion 25A is twice that of 2S. That is, it can be considered that the area of the exposed surface of the island-like structure 25 is approximately twice the area of the base surface covered with the island-like structure 25.

  FIG. 2B shows the relationship between the coverage of the island-like structure 25 and the area of the exposed base surface and the surface of the island-like structure 25. When the coverage of the island-like structure 25 is 0%, that is, when the island-like structure 25 is not formed, the area of the exposed surface of the underlying first conductive film 22 is normalized to 100. When the coverage of the island-like structure 25 is 50%, the exposed surface area of the first conductive film 22 is 50. The area of the region covered with the island structure 25 is also 50, and the area of the exposed surface of the island structure 25 is 100, which is twice that area. Similarly, when the coverage of the island-like structure 25 is 75%, the exposed surface area of the first conductive film 22 is 25, and the exposed surface area of the island-like structure 25 is 150.

  A state where the coverage of the island-like structure 25 is 100% means a state where the entire surface of the first conductive film 22 is covered with a continuous film. In this case, the surface area of the continuous film is equal to the area of the underlying surface. That is, the area of the exposed surface of the island-like structure 25 is 100.

FIG. 3A shows a state where the droplet 51 is attached to the surface of the substrate 50. Let the contact angle of the droplet 51 be θ. Of the interfacial tension acting on the point of action P, which is one point on the edge of the droplet 51, the tension along the interface between the substrate 50 and the droplet 51 is γ _LS, and the tension along the interface between the droplet 51 and the gas is γ _{LS. The} tension along the interface between the substrate 50 and the gas is γ _VS.

  Assuming that the unevenness of the surface of the substrate 50 is r, the energy change when the action point P is displaced by dx toward the outside of the droplet 51 is dE, and the contact angle at this time is θ, the following equation is obtained. It holds. Here, the degree of unevenness r is the ratio of the actual surface area to the surface area when the surface is assumed to be a perfect plane.

  Since dE / dx = 0 in the equilibrium state, the following equation is obtained.

Let θ _{F be} the contact angle when the surface of the substrate 50 is flat. When the surface of the substrate 50 is flat, since r = 1, the following equation is established.

Γ _LS , γ _VS , and γ _VL are eliminated from Equation 2 and Equation 3, and the following equation is obtained.

  When the surface of the substrate 50 is not flat, the unevenness r is greater than 1. Therefore, the following equation holds.

When cos θ _F is positive, that is, when the contact angle θ _F on the flat surface is 0 ° <θ _F <90 °, θ <θ _F and when cos θ _F is negative, that is, 90 ° <θ _F <180 °. In this case, θ> θ _F.

As shown in FIG. 3B, when the contact angle θ _F on the flat surface is 0 ° <θ _F <90 °, the contact angle θ when the surface is uneven as shown in FIG. Smaller than _F. This means that wettability is increased. On the contrary, as shown in FIG. 3D, when the contact angle θ _F on the flat surface is 90 ° <θ _F <180 °, the contact angle θ when the surface is uneven as shown in FIG. 3E. It is larger than θ _F. This means that wettability is reduced.

  The contact angle of copper with the Co surface is less than 90 °. For this reason, when the surface of the Co film is roughened, the wettability is improved as compared with the case where the surface is flat.

  Returning to FIG. 2B, the description will be continued. Comparing the case where the coverage of the island-like structure 25 is 75% and the case where it is 100%, it can be seen that the surface area of the island-like structure 25 is larger when the coverage is 75%. For this reason, when the coverage is 75%, the wettability of the base layer of the seed layer 30 with respect to copper is considered to be higher than the wettability of copper with the surface of the flat Co film.

  Further, when the coverage of the island-like structure 25 is 50% and when it is 100%, the surface area of the island-like structure 25 is equal. When the coverage is 50%, there is a region where the surface of the first conductive film 22 is exposed. For this reason, when the coverage of the island-like structure 25 is 50%, the wettability of the seed layer 30 with respect to the copper is equal to or higher than the wettability of the flat Co surface with respect to copper. Conceivable.

  From the above consideration, it can be seen that the coverage of the island-like structure 25 is preferably 50% or more. The island-like structure 25 is formed of a material having a wettability higher than that of the first conductive film 22 with respect to copper. For this reason, even if the coverage of the island-like structure 25 is less than 50%, the island-like structure 25 is arranged as compared with the case where the seed layer 30 is directly grown on the flat first conductive film 22. Thus, it is apparent that the wettability of the base surface of the seed layer 30 with respect to copper is enhanced.

  The size of each island-shaped portion constituting the island-like structure 25 is about the size of the copper island-shaped portion generated when the seed layer 30 is directly formed on the first conductive film 22, or more than that. If it is large, a sufficient effect of arranging the island-like structures 25 cannot be obtained. In general, the size of a copper island-shaped portion formed when copper is grown on a barrier metal film such as Ta is about 5 nm to 8 nm. Therefore, the height of each particle constituting the island-like structure 25 is preferably 2 nm or less, more preferably 1 nm or less.

  Next, with reference to FIG. 4A to FIG. 4C, the results of evaluating the adhesion of copper to Ta, Ti, and Co will be described.

  Three types of evaluation samples were prepared by forming a copper film on the Ta, Ti, and Co films by chemical vapor deposition (CVD). An experiment was conducted in which a square lattice-shaped marking was placed on the surface of the sample with a diamond marking needle and the copper film was peeled off with an adhesive tape.

  4A to 4C show photographs after a copper film peeling process of samples in which a copper film is formed on a Ta film, a Ti film, and a Co film, respectively. When the copper film was formed on the Ta film, as shown in FIG. 4A, not only the region where the marking was made, but also the copper film in the adjacent region was peeled off. When a copper film is formed on the Ti film, as shown in FIG. 4B, the copper film in the region where the marking is made peels off, but the copper film in the region adjacent thereto does not peel off. When the copper film is formed on the Co film, as shown in FIG. 4C, the copper film in the region where the marking is made is not peeled off.

  From this evaluation result, it can be seen that the adhesion of the copper film is higher in the order of Co, Ti, and Ta in the base surface. High adhesion is considered high wettability. From this evaluation result, it is understood that Ti is more suitable than Ta and Co is more suitable than Ti from the viewpoint of wettability as the conductive material of the island-like structure 25. Note that the island-like structure 25 may be made of a conductive material containing Co, Ti, Zr, Mn, or Ru.

  When the same material is used for the first conductive film 22 and the island-like structure 25 that function as a barrier metal film, nucleation does not occur during the growth of the island-like structure 25, and a film that covers the entire surface from the beginning of growth is formed. End up. In order to form the island-like structure 25 in which the island-like portions are discretely distributed, it is necessary to use a material different from that of the first conductive film 22 for the island-like structure 25. For example, when metal Ti is used for the first conductive film 22, metal Ti cannot be used for the island structure 25. However, when Ti nitride (TiN) is used for the first conductive film 22, it is possible to use metal Ti for the island structure 25.

  Further, in order to make the seed layer 30 a continuous film, it is preferable to select a material having a wettability higher than that of the first conductive film 22 with respect to copper as a material of the island-like structure 25. As an example, when Ta is used for the first conductive film 22, it is preferable to use Ti or Co for the island-like structure 25. Further, when Ti is used for the first conductive film 22, it is preferable to use Co for the island-like structure 25.

  In the first embodiment, after the first conductive film 22 shown in FIG. 1D is formed and before the island-like structure 25 shown in FIG. 1E is formed, reverse sputtering using Ar plasma is performed to obtain the first The surface of the conductive film 22 may be roughened. Further, after forming the island-like structure 25 shown in FIG. 1E and before forming the seed layer 30 shown in FIG. 1F, reverse sputtering using Ar plasma may be performed to further roughen the surface. By roughening the surface, the wettability to copper can be further increased, and the contact resistance can be reduced. When the CVD method is used to form the island-like structure 25, the surface of the island-like structure 25 is roughened by using a reducing plasma typified by hydrogen in combination with the deoxygenation and decarbonization treatment of the island-like structure 25. Also good.

  In Example 1, the seed layer 30 was formed by sputtering in the step shown in FIG. 1F, and the wiring film 31 was formed by electrolytic plating in the step shown in FIG. 1G. Instead of performing electroplating, the recess 21 may be filled with copper only by sputtering. Further, the recess 21 may be filled with copper only by CVD. In this case, by placing the island-like structure 25, the embedding characteristics with copper can be improved.

  In the first embodiment, the concave portion 21 for wiring is filled with copper or a copper alloy, but the island-like structure 25 can be used in other processes for filling copper or a copper alloy. For example, in the single damascene method, the island-like structure 25 can be used for the step of filling the via hole for the interlayer contact or the step of simultaneously filling the via hole and the wiring groove in the dual damascene method.

  Next, with reference to FIGS. 5A to 5F, a method for manufacturing a semiconductor device according to Example 2 will be described.

  The process until the first conductive film 22 shown in FIG. 5A is formed is the same as the process of Example 1 until the first conductive film 22 shown in FIG. 1D is formed. The surface of the first conductive film 22 is covered with the second conductive film 40. For the second conductive film 40, a conductive material having a wettability higher than that of the first conductive film 22 is used for copper. As an example, when Ti or Ta is used for the first conductive film 22, Co is used for the second conductive film 40. The second conductive film 40 is formed by sputtering, CVD, or the like, for example.

As shown in FIG. 5B, the second conductive film 40 is reverse sputtered with Ar plasma. As shown in FIG. 5C, the surface of the second conductive film 40 becomes rough by reverse sputtering. The reverse sputtering conditions are, for example, as follows.
・ Pressure 0.1Pa
・ RF power 1kW
・ Wafer bias 500W
The root mean square roughness of the surface immediately after deposition of the second conductive film 40 was about 0.7 nm, but the root mean square roughness of the surface after reverse sputtering with Ar was about 1.3 nm. As described above, it was confirmed that the surface of the second conductive film 40 was roughened by reverse sputtering. When the CVD method is used to form the second conductive film 40, the surface of the second conductive film 40 is roughened by using a reducing plasma typified by hydrogen, which also serves as a deoxidation and decarbonization process for the second conductive film 40. Surfaceization may be performed.

  As shown in FIG. 5D, a seed layer 30 made of copper is formed on the second conductive film 40 having a rough surface. The formation of the seed layer 30 is the same as the formation method of the seed layer 30 of Example 1 shown in FIG. 1F.

  As shown in FIG. 5E, the wiring film 31 is formed by electroplating copper or a copper alloy using the seed layer 30 as an electrode. Thereafter, the first conductive film 22, the second conductive film 40, the seed layer 30, and the wiring film 31 deposited above the upper surface of the interlayer insulating film 22 are removed by CMP.

  As shown in FIG. 4F, the wiring 31 a made of copper or copper alloy remains in the recess 21.

  When the contact angle of copper on the flat surface of the material of the second conductive film 40 is less than 90 °, the surface is roughened as described with reference to FIGS. 3B to 3C. The wettability can be increased. For this reason, even when the seed layer 30 is thin, the seed layer 30 can be formed in a film shape without being divided into island shapes. The wettability of the second conductive film 40 to copper is higher than the wettability of the first conductive film 22 to copper. For this reason, compared with the case where the surface of the 1st electrically conductive film 22 is roughened and the seed layer 30 is directly formed on it, the wettability with respect to the copper of the base surface of the seed layer 30 can be improved more.

  The treatment for roughening the surface of the second conductive film 40 can be applied to other processes for embedding copper in addition to the process of embedding the recesses 21 for wiring with copper or a copper alloy. For example, a process of roughening the surface of the second conductive film 40 can be applied to a process of filling a via hole in a single damascene method or a process of filling a via hole and a wiring trench simultaneously in a dual damascene method.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Semiconductor substrate 11 Element isolation insulating film 12 MOSFET
15 Interlayer insulating film 16 Conductive plug 20 Interlayer insulating film 21 Recess 22 First conductive film 25 Island-like structure 30 Seed layer 31 Wiring film 31a Wiring 40 Second conductive film 50 Substrate 51 Droplet

Claims (5)

An insulating film formed on the semiconductor substrate;
A recess formed in the insulating film;
A first conductive film covering an inner surface of the recess;
An island-like structure made of a conductive material that is discretely distributed on the surface of the first conductive film and has a wettability higher than that of the first conductive film with respect to copper;
A semiconductor device having a conductive member made of copper or a copper alloy filling the recess. The first conductive film includes at least one metal element selected from the group consisting of Ta, W, Mo, Ti, and Zr;
The semiconductor device according to claim 1, wherein the island-like structure includes at least one metal element selected from the group consisting of Co, Ti, Zr, Mn, and Ru. Forming a recess in an insulating film formed on a semiconductor substrate;
Covering the inner surface of the recess with a first conductive film;
A step of forming an island structure made of a conductive material that is discretely distributed on the surface of the conductive film and has a wettability higher than that of the first conductive film with respect to copper;
And a step of filling the recess with a conductive member made of copper or a copper alloy.   4. The semiconductor device according to claim 3, wherein in the step of forming the island-shaped structure, the island-shaped structure is formed by alternately supplying a source gas and a reducing gas onto the first conductive film. Production method. Forming a recess in an insulating film formed on a semiconductor substrate;
Covering the inner surface of the recess with a first conductive film;
Covering the surface of the conductive film with a second conductive film made of a conductive material having higher wettability with respect to copper than the wettability of the first conductive film with respect to copper;
Performing Ar plasma treatment or reducing plasma treatment on the surface of the second conductive film;
A method of manufacturing a semiconductor device, comprising: subjecting the surface of the second conductive film to Ar plasma treatment or reducing plasma treatment, and then filling the concave portion with a conductive member made of copper or a copper alloy.