JP7343406B2 - How to form metal wiring - Google Patents

Description

The present invention relates to a method for forming metal wiring.

In electronic components such as LSIs, a conductive layer is embedded in a via hole provided in an interlayer insulating layer, and metal wiring layers between the layers are electrically connected by the conductive layer. The conductive layer is embedded in the via hole by forming the conductive layer on the via hole and the surface of the interlayer insulating layer, and then removing the conductive layer on the interlayer insulating layer by chemical mechanical polishing (for example, as described in the patent (See Reference 1).

Here, since poor contact between the conductive layer in the via hole and the metal wiring reduces the yield of electronic components, suppressing the poor contact has become an important issue. In particular, as the via hole node becomes narrower, the contact resistance between the conductive layer and the metal wiring increases.

For example, a natural oxide film is usually formed on the surface of the metal wiring before the step of filling the via hole with a conductive layer. The process of removing this natural oxide film using a dry process before filling the via hole with a conductive layer has become an important process in the manufacturing process of electronic components.

Japanese Patent Application Publication No. 2010-177365

By the way, as the speed of electronic components increases in recent years, low-k materials with low parasitic capacitance are used as interlayer insulating layers. Since this low-k material is generally composed of a low density, if the interlayer insulating layer is exposed to plasma when removing the natural oxide film in a dry process, the interlayer insulating layer will be damaged by the plasma. There is a possibility that you will receive it.

In addition, if the metal components contained in the natural oxide film re-deposit on the inner wall of the via hole in the interlayer insulation layer after the natural oxide film is removed, there is a possibility that the redeposited metal will diffuse into the interlayer insulation layer due to the thermal history of the manufacturing process. be.

When the above phenomenon occurs, the interlayer insulating layer may lose its function as a low-k material, and the reliability of the electronic component may be reduced.

In view of the above circumstances, an object of the present invention is to provide a highly reliable method for forming metal wiring included in electronic components.

In order to achieve the above object, the following forming method is applied to a metal wiring forming method according to one embodiment of the present invention.
A laminated structure is prepared that includes a metal wiring layer containing copper and an interlayer insulating layer that is laminated on the metal wiring layer and is provided with an opening through which a part of the surface of the metal wiring layer is exposed.
Sputtering is performed on the surface of the interlayer insulating layer and the exposed surface of the metal wiring layer exposed in the opening, and the copper aluminum layer deposited on the surface of the interlayer insulating layer is thicker than the copper aluminum layer deposited on the exposed surface. The copper aluminum layer is formed so that the thickness of the copper aluminum layer is increased.
By exposing the copper-aluminum layer deposited on the surface and the exposed surface of the interlayer insulating layer to plasma, the thickness of the copper-aluminum layer deposited on the surface is reduced, and the copper-aluminum layer deposited on the exposed surface is reduced. are removed from the exposed surface, and the natural oxide film of the metal wiring layer formed on the exposed surface is also removed from the exposed surface.

According to such a method of forming metal wiring, an electronic component including highly reliable metal wiring can be provided without impairing the function of the interlayer insulating layer.

In the method for forming metal wiring, the sputtering method may be a sputtering method that prioritizes isotropic sputtering over anisotropic sputtering, or a sputtering method that prioritizes isotropic sputtering over anisotropic sputtering, or A sputtering method performed in parallel may also be employed.

According to this method of forming metal wiring, it is possible to reliably balance the thickness of the copper-aluminum layer deposited on the surface and exposed surface of the interlayer insulating layer, thereby providing an electronic structure with highly reliable metal wiring. Parts provided.

In the method for forming metal wiring, the plasma is a plasma generated by discharging an inert gas, and physical etching using the plasma reduces the thickness of the copper-aluminum layer deposited on the surface. The copper aluminum layer and the native oxide film deposited on the exposed surface may be removed.

According to such a method of forming metal wiring, the natural oxide film is removed without impairing the function of the interlayer insulating layer, and an electronic component with highly reliable metal wiring is provided.

In the above method for forming metal wiring, an etching method in which anisotropic etching is prioritized over isotropic etching may be adopted as the physical etching.

According to such a method of forming metal wiring, the natural oxide film is removed without impairing the function of the interlayer insulating layer, and an electronic component with highly reliable metal wiring is provided.

In the above method for forming metal wiring, the interlayer insulating layer may be a Low-k layer.

According to such a method of forming metal wiring, an electronic component having highly reliable metal wiring can be provided without impairing the function of the Low-k layer as an interlayer insulating layer.

In the above method for forming metal wiring, the copper aluminum layer may be _{a two-} layer CuAl layer.

According to such a method of forming metal wiring, an oxide barrier film is formed on the side surface of the opening in the interlayer insulating layer, and the function of the low-k layer is not impaired and highly reliable metal wiring is provided. Electronic components are provided.

In the method for forming metal wiring, the opening may be a via hole or a trench provided in the interlayer insulating layer, and the opening width of the via hole or the line width of the trench may be 20 nm or less.

According to such a method of forming metal wiring, an electronic component with highly reliable metal wiring can be provided without impairing the function of the interlayer insulating layer even with the above opening width or line width. Ru.

In the above method for forming metal wiring, after removing the natural oxide film, a copper-aluminum wiring may be formed in the opening by sputtering or plating.

According to such a method of forming metal wiring, an electronic component including highly reliable metal wiring is provided.

In the above method for forming a metal interconnect, the components of the copper aluminum layer may be the same as those of the copper aluminum interconnect.

According to such a method of forming metal wiring, the step of removing the copper-aluminum layer is not necessary, and the manufacturing process of metal wiring is simplified.

As described above, according to the present invention, a highly reliable method for forming metal wiring included in an electronic component is provided.

Figures (a) and (b) are schematic cross-sectional views showing part of a laminated structure of an interlayer insulating layer, metal wiring, and metal wiring layer in the upper layer of an electronic component. FIG. 2 is a schematic cross-sectional view showing the manufacturing process of the laminated structure illustrated in FIG. 1(a). FIG. 2 is a schematic cross-sectional view showing the manufacturing process of the laminated structure illustrated in FIG. 1(a). FIG. 2 is a schematic cross-sectional view showing the manufacturing process of the laminated structure illustrated in FIG. 1(b). FIG. 2 is a schematic cross-sectional view showing the manufacturing process of the laminated structure illustrated in FIG. 1(b). FIG. 3 is a schematic cross-sectional view showing an example of the effect of the present embodiment. It is a typical sectional view showing a modification of a manufacturing process of a layered structure.

Embodiments of the present invention will be described below with reference to the drawings. In each drawing, XYZ axis coordinates may be introduced. In addition, the same members or members having the same function may be given the same reference numerals, and the description may be omitted as appropriate after the member has been described.

FIGS. 1A and 1B are schematic cross-sectional views showing a part of a laminated structure of an interlayer insulating layer, a metal wiring, and a metal wiring layer in the upper layer of an electronic component.

FIGS. 1(a) and 1(b) show an interlayer insulating layer, metal wiring, and metal wiring layer in the upper layer of an electronic component (for example, a semiconductor device) including a transistor, a resistor, a capacitor, a memory, etc. .

The laminated structure 1 shown in FIG. 1A includes metal wiring layers 10 and 30, interlayer insulating layers 11, 21, and 31, and a metal wiring 20.

The metal wiring layer 10 is, for example, a wiring layer provided below the laminated structure 1 and electrically connected to any one of a transistor, a resistor, a capacitor, a memory, etc. (not shown). Alternatively, the potential of the metal wiring layer 10 may be floating. An interlayer insulating layer 11 is provided around the outer periphery of the metal wiring layer 10 .

The metal wiring 20 has a lower end 20d electrically connected to the metal wiring layer 10, and an upper end 20u connected to the metal wiring layer 30. The interlayer insulating layer 21 is laminated on the metal wiring layer 10 and the interlayer insulating layer 11 , and the outer periphery of the metal wiring 20 is surrounded by the interlayer insulating layer 21 . For example, the metal wiring 20 is buried in an opening 21h such as a via hole provided in the interlayer insulating layer 21. The opening 21h may be a trench, for example, in addition to a via hole.

The metal wiring layer 30 is electrically connected to the upper end 20u of the metal wiring 20. The interlayer insulating layer 31 is laminated on the interlayer insulating layer 21 , and the interlayer insulating layer 31 is provided around the outer periphery of the metal wiring layer 30 .

The material of the metal wiring layers 10 and 30 and the metal wiring 20 is a material containing Cu. For example, the material of the metal wiring layers 10 and 30 and the metal wiring 20 is a Cu alloy. Here, the Cu alloy is an intermetallic compound such as CuAl ₂ (CuAl ₂ -θ layer). The material of the interlayer insulating layers 11, 21, and 31 is, for example, a low-k material (CVD-SiOC, CVD-SiO _2, etc.) with a dielectric constant of 2 or less.

When the material of the metal wiring layer 30 is pure Cu, a barrier layer may also be provided between the metal wiring layer 30 and the interlayer insulating layers 21 and 31.

Further, in the laminated structure 2 shown in FIG. 1(b), an interlayer insulating layer 31 is further provided on the interlayer insulating layer 21, and an opening 31h having an opening width wider than the opening 21h is formed in the interlayer insulating layer 31. ing. A wiring portion 25a of the metal wiring 25 is provided in the opening 21h, and a wiring portion 25b of the metal wiring 25, which has a wider line width than the wiring portion 25a, is provided in the opening 31h. That is, the metal wiring 25 has a wiring part 25a and a wiring part 25b. In other words, the wiring portion 25a is a via wiring, and the wiring portion 25b is an electrode. Such a laminated structure is also included in this embodiment. The material of the metal wiring 25 is a Cu alloy such as CuAl ₂ (CuAl ₂ -θ layer).

The manufacturing process of the laminated structure 1 shown in FIG. 1(a) will be explained.

2(a) to 3(b) are schematic cross-sectional views showing the manufacturing process of the laminated structure 1 illustrated in FIG. 1(a).

As shown in FIG. 2A, first, a laminated structure 1a having a metal wiring layer 10 and interlayer insulating layers 11 and 21 is prepared. In the laminated structure 1a, an interlayer insulating layer 11 is provided around the outer periphery of the metal wiring layer 10, and an interlayer insulating layer 21 is laminated on the metal wiring layer 10 and the interlayer insulating layer 11. The interlayer insulating layer 21 is provided with an opening 21h through which a portion of the surface 10s of the metal wiring layer 10 is exposed.

The opening 21h may be a via hole penetrating between the upper and lower main surfaces of the interlayer insulating layer 21, or may be a trench extending in a direction parallel to the main surface of the interlayer insulating layer 21. For example, when the opening width (line width in the case of a trench) of the opening 21h is 5 to 15 nm, the depth of the opening 21h is 20 to 40 nm.

The laminated structure 1a is formed by a combination of manufacturing processes such as film forming techniques such as CVD and sputtering, dry or wet etching techniques, and photolithography. Here, when the opening 21h is formed in the interlayer insulating layer 21 and a part of the metal wiring layer 10 is exposed, a natural oxide film (for example, copper oxide) is formed on the exposed surface 101 of the metal wiring layer 10. There is.

Next, as shown in FIG. 2(b), a copper aluminum layer 201 is formed on the surface 21s of the interlayer insulating layer 21 and the exposed surface 101 of the metal wiring layer 10 exposed in the opening 21h. The components of the copper aluminum layer 201 are the same as those of the metal wiring 20. For example, the copper aluminum layer 201 is a Cu alloy such as a CuAl ₂ layer (CuAl ₂ -θ layer). The copper aluminum layer 201 is formed by a sputtering method using a Cu alloy target such as CuAl ₂ in a reduced pressure atmosphere.

Here, as the sputtering method, a sputtering method in which the directivity of sputtered particles is relaxed is applied. For example, when a sputtering method that prioritizes isotropic sputtering over anisotropic sputtering is applied, the copper-aluminum layer deposited on the surface 21s of the interlayer insulating layer 21 is thicker than the copper-aluminum layer 201 deposited on the exposed surface 101. The copper aluminum layer 201 is formed so that the thickness of the copper aluminum layer 201 is increased.

For example, anisotropic sputtering refers to, for example, setting a relatively long distance between the substrate including the laminated structure 1a and the target, and using plasma in a low pressure region (for example, 10 ^-6 Pa to 10 ^-1 Pa). This refers to the sputtering method used. Isotropic sputtering refers to the method in which the distance between the substrate and target is set relatively short and plasma in the medium to high pressure region (for example, 10 ^-1 Pa to 10 Pa) is used. This applies to sputtering methods. For plasma discharge, a magnetron discharge method using a plasma confinement method using a mirror magnetic field, and a discharge method that self-maintains a plasma state by applying a high voltage to the material itself are adopted.

By adopting a sputtering method in which such step coverage is suppressed, sputtering particles are less likely to reach the exposed surface 101 than the surface 21s, and the thickness of the copper-aluminum layer 201 deposited on the exposed surface 101 is greater than the The thickness of the copper aluminum layer 201 deposited on the surface 21s of the insulating layer 21 becomes thicker. For example, a copper aluminum layer 201 with a thickness of 2 nm to 5 nm is formed on the surface 21s, and a copper aluminum layer 201 with a thickness of 0.5 nm to 1.5 nm is formed on the exposed surface 101, for example.

Next, as shown in FIG. 2C, the copper-aluminum layer 201 deposited on the surface 21s of the interlayer insulating layer 21 and the exposed surface 101 is physically etched by, for example, being exposed to plasma.

In the physical etching, plasma in which an inert gas such as Ar, He, Ne, or Xe is discharged is used as the plasma gas. As this physical etching using plasma, a sputtering method with improved directivity of plasma ions is applied. For example, an etching method that gives priority to anisotropic etching over isotropic etching is applied. For example, a negative potential bias is superimposed on the substrate including the laminated structure 1a, and plasma processing is performed in a low pressure region (for example, 10 ⁻³ Pa to 10 ⁻¹ Pa).

As a result, ions in the plasma easily reach the copper-aluminum layer 201 deposited on the surface 21s of the interlayer insulating layer 21 as well as the copper-aluminum layer 201 deposited on the exposed surface 101. Both copper-aluminum layers 201 deposited on exposed surface 101 are etched simultaneously. However, since the copper aluminum layer 201 deposited on the surface 21s is thicker than the copper aluminum layer 201 deposited on the exposed surface 101, the copper aluminum layer 201 deposited on the exposed surface 101 is removed first, and the surface 21s The copper aluminum layer 201 deposited on the surface remains on the surface 21s.

As a result, the thickness of the copper-aluminum layer 201 deposited on the surface 21s is reduced, and the copper-aluminum layer 201 deposited on the exposed surface 101 is removed from the exposed surface 101. Further, the exposed surface 101 is over-etched by physical etching, and the natural oxide film of the metal wiring layer 10 formed on the exposed surface 101 is removed from the exposed surface 101.

Next, as shown in FIG. 3A, after the natural oxide film on the exposed surface 101 is removed, a metal wiring layer 20L made of CuAl ₂ is formed by sputtering or on the opening 21h and the copper aluminum layer 201. Formed by plating method. After the metal wiring layer 20L is formed on the opening 21h and the copper-aluminum layer 201, a reflow treatment at 200 to 350° C. may be performed as necessary.

Next, as shown in FIG. 3B, the surplus of the metal wiring layer 20L on the interlayer insulating layer 21 is removed by chemical mechanical polishing, and the surplus is removed and the remaining metal wiring 20 is placed in the opening 21h. is formed. After this, as shown in FIG. 1A, an interlayer insulating layer 31 is formed on the interlayer insulating layer 21, and a metal wiring layer 30 electrically connected to the metal wiring 20 is further formed in the interlayer insulating layer 31. is formed.

The manufacturing process of the laminated structure 2 shown in FIG. 1(b) will be explained.

4(a) to 5(b) are schematic cross-sectional views showing the manufacturing process of the laminated structure 2 illustrated in FIG. 1(b).

As shown in FIG. 4(a), a laminated structure 2a having a metal wiring layer 10 and interlayer insulating layers 11, 21, and 31 is prepared. In the laminated structure 2a, an opening 21h is provided in the interlayer insulating layer 21, and an opening 31h communicating with the opening 21h is provided in the interlayer insulating layer 31. The opening width of the opening 31h is formed wider than the opening width of the opening 21h.

The laminated structure 2a is formed by, for example, a combination of a film forming method such as CVD and sputtering, a dry or wet etching method, and a wafer process such as photolithography. After the opening 21h is formed in the interlayer insulating layer 21, a natural oxide film may be formed on the exposed surface 101 of the metal wiring layer 10.

Next, as shown in FIG. 4B, the surface 31s of the interlayer insulating layer 31, the surface 21s of the interlayer insulating layer 21 exposed in the opening 21h, and the metal wiring layer 10 exposed in the opening 21h. A copper aluminum layer 201 is formed on the exposed surface 101.

Here, as the sputtering method, a sputtering method in which the directivity of sputtered particles is relaxed is applied. For example, a sputtering method is applied that prioritizes isotropic sputtering over anisotropic sputtering, as in the manufacturing process of the laminated structure 1a. As a result, the thickness of the copper-aluminum layer 201 deposited on the surface 31s of the interlayer insulating layer 31 and the surface 21s of the interlayer insulating layer 21 becomes thicker than the thickness of the copper-aluminum layer 201 deposited on the exposed surface 101. Note that since the opening width of the opening 31h is wider than the opening width of the opening 21h, the thickness of the copper-aluminum layer 201 deposited on the surface 31s of the interlayer insulating layer 31 is the same as that of the copper-aluminum layer deposited on the surface 21s of the interlayer insulating layer 21. It is formed thicker than the thickness of 201.

Next, as shown in FIG. 4(c), the copper aluminum layer 201 deposited on the surface 31s of the interlayer insulating layer 31, the surface 21s of the interlayer insulating layer 21, and the exposed surface 101 is coated, for example, in the manufacturing process of the laminated structure 1a. Similarly, physical etching with improved directivity is performed.

As a result, the thickness of the copper-aluminum layer 201 deposited on the surfaces 31s and 21s is reduced, and the copper-aluminum layer 201 deposited on the exposed surface 101 is removed from the exposed surface 101. Further, the exposed surface 101 is over-etched by physical etching, and the natural oxide film of the metal wiring layer 10 formed on the exposed surface 101 is removed from the exposed surface 101.

Next, as shown in FIG. 5A, a metal wiring layer _25L made of CuAl2 is formed on the openings 31h, 21h and the copper-aluminum layer 201 by sputtering or plating. The metal wiring layer 25L may be subjected to a reflow treatment at 200 to 350° C. if necessary.

Next, as shown in FIG. 5(b), the excess portion of the metal wiring layer 25L on the interlayer insulating layer 31 is removed by chemical mechanical polishing, and the excess portion is removed and left in the openings 31h and 21h. Metal wiring 25 is formed. That is, as shown in FIG. 1B, a wiring portion 25b of the metal wiring 25 is formed in the opening 31h, and a wiring portion 25a of the metal wiring 25 is formed in the opening 21h. Thereby, the laminated structure 2 is formed. The copper aluminum layer 201 on the surface 21s is incorporated as a part of the metal wiring 25.

The operation of this embodiment will be explained.

FIG. 6 is a schematic cross-sectional view showing an example of the operation of this embodiment.

In this embodiment, when removing the copper aluminum layer 201 deposited on the exposed surface 101 and the natural oxide film of the metal wiring layer 10 formed on the exposed surface 101 by physical etching, the interlayer insulating layer 201 is removed by physical etching. The surface 21s of is covered with a copper aluminum layer 201. That is, the copper aluminum layer 201 deposited on the surface 21s functions as a protective layer for the interlayer insulating layer 21 during physical etching.

As a result, the surface 21s of the interlayer insulating layer 21 is less likely to be damaged by plasma and maintains its function as a low-k material.

Furthermore, due to the high reactivity between aluminum in the copper-aluminum layer 201 and oxygen in the interlayer insulating layer 21, an extremely thin layer may be used at the interface between the protective layer and the interlayer insulating layer 21. An aluminum oxide (AlO _x ) layer is formed. This aluminum oxide layer functions as a barrier layer for metal components and suppresses diffusion of Cu and Al in the protective layer into the interlayer insulating layer 21.

Further, a copper aluminum layer 201 is formed on the exposed surface 101 when the native oxide film is removed. A portion of this copper-aluminum layer 201 re-attaches to the side surface 21w of the opening 21h during physical etching.

As a result, due to the high reactivity between aluminum in the copper aluminum layer 201 and oxygen in the interlayer insulating layer 21, an extremely thin aluminum oxide layer is also formed at the interface between the metal wiring 20 and the interlayer insulating layer 21. It is thought that Due to the barrier properties of the aluminum oxide layer, diffusion of Cu and Al in the metal wiring 20 into the interlayer insulating layer 21 is suppressed.

Furthermore, since the components of the copper-aluminum layer 201 and the metal wiring 20 are the same, excellent adhesion is achieved between the metal wiring 20 and the interlayer insulating layer 21 due to the presence of the copper-aluminum redeposited on the side surface 21w. is obtained.

Furthermore, since the components of the copper-aluminum layer 201 and the metal wiring 20 are the same, there is no need to remove the copper-aluminum re-attached to the side surface 21w, and the manufacturing process can be simplified. Damage to the interlayer insulating layer 21 is suppressed because the step of removing the copper aluminum reattached to the side surface 21w is not necessary.

Furthermore, in the manufacturing process of the laminated structure 2a, although the copper aluminum layer 201 remains on the surface 21s of the interlayer insulating layer 21, the components of the metal wiring 25 embedded in the openings 31h and 21h are the same as the copper aluminum layer 201. Therefore, the copper aluminum layer 201 is incorporated into a part of the metal wiring 25. This eliminates the need for the step of removing the copper-aluminum layer 201 remaining on the surface 21s.

Note that depending on the sputtering conditions, the copper aluminum layer 201 may be deposited not only on the exposed surface 101 but also on the side surface of the opening 21h or the side surface of the opening 31h. The copper aluminum layer 201 deposited on the side surface of the opening 21h or the side surface of the opening 31h may be removed by physical sputtering, or may remain on the side surface of the opening 21h or the side surface of the opening 31h after physical sputtering. Even if the copper-aluminum layer 201 remains on the side surface of the opening 21h or the side surface of the opening 31h, the same effect as when the copper-aluminum layer 201 on the exposed surface 101 re-attaches to the side surface of the opening 21h or the side surface of the opening 31h is achieved. .

FIG. 7 is a schematic cross-sectional view showing a modification of the manufacturing process of the laminated structure.

In the sputtering film formation of the copper aluminum layer 201, the normal line 40n of the Cu alloy target 40 used as a sputtering target and the normal line 21n of the interlayer insulating layer 21 may be made non-parallel. During sputtering film formation, the substrate including the laminated structure 1a may be appropriately rotated in a direction parallel to the surface 21s.

According to such a method, the directivity of sputtered particles is further relaxed, and the thickness of the copper-aluminum layer 201 deposited on the surface 21s of the interlayer insulating layer 21 is greater than the thickness of the copper-aluminum layer 201 deposited on the exposed surface 101. becomes thicker. Thereby, a difference in the thickness of the copper aluminum layer 201 deposited on the exposed surface 101 and the thickness of the copper aluminum layer 201 deposited on the surface 21s of the interlayer insulating layer 21 can be more reliably provided. Note that this modification may be applied to the manufacturing process of the laminated structure 2a.

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments and can be modified in various ways. Each embodiment is not necessarily an independent form, and can be combined to the extent technically possible.

1, 1a, 2, 2a... Laminated structure 10, 20L, 25L, 30... Metal wiring layer 10s, 21s, 31s... Surface 11, 21, 31... Interlayer insulation layer 20, 25... Metal wiring 20u... Upper end 20d... Lower end 21h, 31h...Opening 21w...Side surface 21n, 40n...Normal line 25a, 25b...Wiring part 40...Cu alloy target 101...Exposed surface 201...Copper aluminum layer

Claims (9)

preparing a laminated structure having a metal wiring layer containing copper and an interlayer insulating layer laminated on the metal wiring layer and provided with an opening through which a part of the surface of the metal wiring layer is exposed;
Regarding the copper-aluminum layer formed by sputtering on the surface of the interlayer insulating layer and the exposed surface of the metal wiring layer exposed in the opening, the thickness of the interlayer insulating layer is smaller than the thickness of the copper-aluminum layer deposited on the exposed surface. forming the copper-aluminum layer so that the thickness of the copper-aluminum layer deposited on the surface is thick;
By exposing the surface of the interlayer insulating layer and the copper-aluminum layer deposited on the exposed surface to plasma, the thickness of the copper-aluminum layer deposited on the surface is reduced, and the copper-aluminum layer deposited on the exposed surface is reduced. A method for forming a metal wiring, comprising: removing the metal wiring layer from the exposed surface, and removing a natural oxide film of the metal wiring layer formed on the exposed surface from the exposed surface. A method for forming a metal wiring according to claim 1, comprising:
As the sputtering method, a sputtering method in which isotropic sputtering is prioritized over anisotropic sputtering, or a sputtering method in which the normal line of the sputtering target and the normal line of the interlayer insulating layer are made non-parallel is adopted. How to form metal wiring. A method for forming a metal wiring according to claim 1 or 2, comprising:
The plasma is a plasma in which an inert gas is discharged, and physical etching using the plasma reduces the thickness of the copper-aluminum layer deposited on the surface, and removes the copper-aluminum layer deposited on the exposed surface. A method for forming a metal wiring, which removes the natural oxide film. The method for forming a metal wiring according to claim 3, comprising:
A method for forming a metal wiring, wherein an etching method is adopted in which anisotropic etching is prioritized over isotropic etching as the physical etching. A method for forming a metal wiring according to any one of claims 1 to 4, comprising:
A method of forming a metal wiring using a Low-k layer as the interlayer insulating layer. A method for forming a metal wiring according to any one of claims 1 to 5, comprising:
A method for forming a metal wiring, in which _two layers of CuAl are used as the copper aluminum layer. A method for forming a metal wiring according to any one of claims 1 to 6, comprising:
The opening is a via hole or a trench provided in the interlayer insulating layer, and the opening width of the via hole or the line width of the trench is 20 nm or less. A method for forming a metal wiring according to any one of claims 1 to 7, comprising:
A method for forming a metal wiring, comprising: removing the natural oxide film, and then forming a copper-aluminum wiring in the opening by a sputtering method or a plating method. 9. The method of forming a metal wiring according to claim 8,
The composition of the copper-aluminum layer is the same as the composition of the copper-aluminum wiring. A method for forming a metal wiring.

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