JP2021111757A - Formation method of metal wiring - Google Patents

Abstract

To provide a formation method of metal wiring which does not decrease the reliability of electronic components including metal wiring formed in openings of an interlayer insulating layer.SOLUTION: In a formation method of a metal wiring according to an embodiment of the present invention, a lamination structure is prepared that includes a metal wiring layer containing copper, and an interlayer insulating layer laminated on the metal wiring layer and provided with an opening that exposes a part of the surface of the metal wiring layer. Plasma containing oxygen gas is exposed to the side surface of the opening. A copper-aluminum layer is formed along the side surface of the opening by a sputtering method.SELECTED DRAWING: Figure 1

Description

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

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

JP-A-2010-177365

By the way, with the recent increase in speed of electronic components, a Low-k material having a small parasitic capacitance is used as an interlayer insulating layer. This Low-k material is generally composed of a low-density material. Therefore, how to prevent metal diffusion from the conductive layer formed in the opening to the interlayer insulating layer becomes an important issue. For example, when metal diffusion occurs from the conductive layer to the interlayer insulating layer, the dielectric constant of the interlayer insulating layer changes or electrical leakage occurs in the interlayer insulating layer, which reduces the reliability of electronic components. there is a possibility.

In view of the above circumstances, an object of the present invention is to provide a method for forming a metal wiring that does not reduce the reliability of an electronic component including the metal wiring formed in the opening of the interlayer insulating layer.

In order to achieve the above object, in the method for forming a metal wiring according to an embodiment of the present invention, an opening that is laminated on a metal wiring layer containing copper and the metal wiring layer, and a part of the surface of the metal wiring layer is exposed. A laminated structure having an interlayer insulating layer provided with the above is prepared.
Oxygen ions and oxygen radicals are exposed to the side surfaces of the opening.
A copper-aluminum layer is formed along the side surface of the opening by the sputtering method.

With such a metal wiring forming method, a barrier layer containing an oxide is formed between the interlayer insulating layer and the copper-aluminum layer, and a highly reliable metal wiring structure can be obtained.

In the method for forming the metal wiring, hydrogen ions and hydrogen radicals may be exposed to the side surface before the plasma containing oxygen gas is exposed to the side surface.

With such a metal wiring forming method, there is no residue between the interlayer insulating layer and the copper-aluminum layer, and a highly reliable metal wiring structure can be obtained.

In the method for forming the metal wiring, the natural oxide film of the metal wiring layer exposed at the opening may be removed from the metal wiring layer after the copper-aluminum layer is formed on the side surface.

With such a metal wiring forming method, the natural oxide film is removed from the metal wiring layer, and a highly reliable metal wiring structure can be obtained.

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

With such a metal wiring forming method, high-speed operation is possible and a highly reliable metal wiring structure can be obtained.

In the method for forming the metal wiring, a CuAl ₂ layer may be used as the copper-aluminum layer.

With such a metal wiring forming method, a metal wiring containing copper aluminum is formed in a narrow opening.

In the method for forming the metal wiring, 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 may be 20 nm or less.

With such a metal wiring forming method, a metal wiring containing copper aluminum can be formed even with an opening of the above size.

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

In such a method of forming the metal wiring, the copper-aluminum wiring is formed in the opening after the copper-aluminum layer is formed in the opening.

In the method for forming the metal wiring, the component of the copper-aluminum layer may be the same as the component of the copper-aluminum wiring.

With such a metal wiring forming method, a copper-aluminum layer having the same composition and a copper-aluminum wiring are formed in the opening.

As described above, according to the present invention, there is provided a method for forming metal wiring that does not reduce the reliability of electronic components.

It is a schematic cross-sectional view which shows a part of the laminated structure of the interlayer insulation layer, the metal wiring, and the metal wiring layer in the upper layer of an electronic component. It is a schematic cross-sectional view which shows the manufacturing process of the laminated structure 1 exemplified in FIG. 1 (a). It is a schematic cross-sectional view which shows the manufacturing process of the laminated structure 1 exemplified in FIG. 1 (a). It is a schematic cross-sectional view which shows the manufacturing process of the laminated structure 2 exemplified in FIG. 1 (b). It is a schematic cross-sectional view which shows the manufacturing process of the laminated structure 2 exemplified in FIG. 1 (b). It is a schematic cross-sectional view which shows the modification of the manufacturing process of a laminated structure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. XYZ axis coordinates may be introduced in each drawing. Further, the same member or a member having the same function may be designated by the same reference numeral, and the description may be omitted as appropriate after the description of the member.

1 (a) and 1 (b) 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 an upper layer of an electronic component.

1 (a) and 1 (b) show an interlayer insulating layer as a metal wiring structure, a metal wiring, and a metal wiring in an upper layer of an electronic component (for example, a semiconductor device) including a transistor, a resistor, a capacitor, a memory, and the like. Layers are shown.

The laminated structure 1 shown in FIG. 1A includes metal wiring layers 10 and 30, interlayer insulating layers 11, 21 and 31, and 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, and the like (not shown). Alternatively, the potential of the metal wiring layer 10 may be floating. An interlayer insulating layer 11 is provided on the outer periphery of the metal wiring layer 10.

The lower end 20d of the metal wiring 20 is electrically connected to the metal wiring layer 10, and the upper end 20u thereof is 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 embedded in an opening 21h such as a via hole provided in the interlayer insulating layer 21. The opening 21h may be, for example, a trench in addition to the via hole.

The metal wiring 20 has a copper-aluminum layer 200 and a copper-aluminum wiring 202. The copper-aluminum layer 200 is in contact with the interlayer insulating layer 21, and is provided between the interlayer insulating layer 21 and the copper-aluminum wiring 202.

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 on the outer periphery of the metal wiring layer 30.

The materials of the metal wiring layers 10 and 30 and the metal wiring 20 are materials containing Cu. For example, the materials of the metal wiring layers 10 and 30, the copper-aluminum layer 200 of the metal wiring 20, and the copper-aluminum wiring 202 are Cu alloys. 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 having a relative permittivity of 2 or less (CVD-SiOC, CVD-SiO _2, etc.).

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. Since the copper-aluminum layer 200 and the copper-aluminum wiring 202 are composed of the same components, the boundary between the copper-aluminum layer 200 and the copper-aluminum wiring 202 may disappear.

Further, in the laminated structure 2 shown in FIG. 1B, 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. The opening 21h is provided with a wiring portion 25a of the metal wiring 25, and the opening 31h is provided with a wiring portion 25b of the metal wiring 25 having a wider line width than the wiring portion 25a. That is, the metal wiring 25 has a wiring portion 25a and a wiring portion 25b. In other words, the wiring portion 25a is a via wiring, and the wiring portion 25b is an electrode.

The metal wiring 25 has a copper-aluminum layer 250 and a copper-aluminum wiring 252. The copper-aluminum layer 250 is in contact with the interlayer insulating layers 21 and 31, and is provided between the interlayer insulating layers 21 and 31 and the copper-aluminum wiring 252. The copper-aluminum layer 250 and the copper-aluminum wiring 252 are composed of the same components. For example, the material of the copper-aluminum layer 250 and the copper-aluminum wiring 252 is a Cu alloy such as _{CuAl 2} (CuAl _{2-θ layer).} Therefore, the boundary between the copper-aluminum layer 250 and the copper-aluminum wiring 252 may disappear.

Such a laminated structure 2 is also included in the present embodiment.

The manufacturing process of the laminated structure 1 shown in FIG. 1A will be described.

2 (a) to 3 (c) are schematic cross-sectional views showing a 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, the interlayer insulating layer 11 is provided on the outer periphery of the metal wiring layer 10, and the 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 in which a part 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 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 combining, for example, a film forming technique such as CVD and sputtering, an etching technique using a dry or wet method, and a manufacturing process such as 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. 2B, hydrogen ions and / or hydrogen radicals are exposed to the surface 21s of the interlayer insulating layer 21, the side surface 21w of the opening 21h, and the exposed surface 101. Hydrogen ions and / or hydrogen radicals are exposed using, for example, a plasma discharged from _{H 2 / Ar gas.} As a result, when a residue adheres to or remains on the surface 21s, the side surface 21w, and the exposed surface 101 during the manufacturing process of the laminated structure 1a, the hydrogen plasma causes the residue from the surface 21s, the side surface 21w, and the exposed surface 101. Is removed. The residue is, for example, foreign matter or particles (hereinafter, foreign matter or the like) other than the components of the interlayer insulating layer 21, and corresponds to, for example, carbides, hydroxyl groups, water, ceramic components, metal components and the like.

In the hydrogen surface treatment, a hydrogen plasma treatment in which the directivity of the plasma gas is relaxed is applied with the intention of evenly exposing the hydrogen plasma along the surface 21s, the side surface 21w, and the exposed surface 101. For example, hydrogen plasma in which isotropic plasma is prioritized over anisotropic plasma is applied. Alternatively, hydrogen radicals may be exposed by particles in a radical state that do not exhibit ionicity, and for example, a known remote plasma can be adopted.

For example, the anisotropic plasma is a plasma in a low pressure region (for example, 10 ^{-3 Pa to -1} Pa) in which a relatively long distance is set between the substrate including the laminated structure 1a and the target. The discharge to be used corresponds to the isotropic plasma, in which the distance between the substrate and the target is set relatively short, and the plasma in the medium pressure region to the high pressure region (for example, 10 ^-1 Pa to 10 Pa) is used. Discharge is applicable. For plasma discharge, a discharge method such as a capacitive coupling type or an inductively coupled type is adopted.

Next, as shown in FIG. 2C, oxygen ions and / or oxygen radicals are exposed to the surface 21s, the side surface 21w, and the exposed surface 101. As oxygen ions and / or oxygen radicals, for example, _{plasma discharged from O 2} / Ar gas is used for exposure. As a result, the surface 21s, the side surface 21w, and the exposed surface 101 after the foreign matter and the like are removed are oxidized, and an ultrathin oxide layer is formed on the surface 21s, the side surface 21w, and the exposed surface 101.

In the oxygen surface treatment, the oxygen plasma treatment in which the directivity of the plasma gas is relaxed is applied with the intention of evenly exposing the oxygen plasma along the surface 21s, the side surface 21w, and the exposed surface 101. For example, an oxygen plasma that prioritizes isotropic plasma over anisotropic plasma is applied. Alternatively, oxygen radicals may be exposed by particles in a radical state that do not exhibit ionicity, and for example, a known remote plasma can be adopted.

Next, as shown in FIG. 2D, a copper-aluminum layer 200 is formed on the exposed surface 101 and each of the surface 21s and the side surface 21w by sputtering film formation.

As the sputtering method, a sputtering method in which the directivity of the sputtering particles is improved is applied from the intention of forming the copper-aluminum layer 200 along the exposed surface 101, the surface 21s and the side surface 21w. For example, a sputtering method that prioritizes anisotropic sputtering over isotropic sputtering is applied.

For example, the anisotropic sputtering, for example, to set relatively long distance between the substrate and the target, including the laminated structure 1a, a plasma of low pressure region (for ^{example, 10} -6 ^Pa~10 -1 Pa) The sputtering method to be used is applicable. In isotropic sputtering, the distance between the substrate and the target is set relatively short ^{, and plasma in the medium pressure region to the high pressure region (for example, 10 -3} Pa to 10 Pa) is used. The sputtering method to be used is applicable. For plasma discharge, a magnetron discharge method based on a plasma confinement method using a mirror magnetic field and a discharge method that self-maintains the plasma state by applying a high voltage to the material itself combined with the magnetron discharge method are adopted. As an example of the anisotropic sputtering rig, for example, a sputtering method such as LTS (Long Through Sputtering) is applied.

Next, as shown in FIG. 3A, the copper-aluminum layer 200 deposited on the surface 21s of the interlayer insulating layer 21 and the exposed surface 101 is physically etched.

In physical etching, plasma discharged from an inert gas such as Ar, He, or Xe is used as the plasma gas. As the physical etching using this plasma, a sputtering etching method in which a substrate bias is applied to improve the directivity of plasma ions is applied. For example, an etching method in which anisotropic etching is prioritized over isotropic etching is applied. For example, a negative potential bias is superimposed on a substrate comprising a laminated structure 1a, a low pressure region ^(e.g., 10 -2 ^Pa~10Pa) plasma treatment is performed.

As a result, the ions in the plasma easily reach the copper-aluminum layer 200 deposited on the surface 21s of the interlayer insulating layer 21 as well as the copper-aluminum layer 200 deposited on the exposed surface 101, and are deposited on the surface 21s and the exposed surface 101. , Both copper-aluminum layers 200 are etched at the same time.

However, since the opening width of the opening 21h is narrow and the thickness of the copper-aluminum layer 200 deposited on the surface 21s is thicker than the thickness of the copper-aluminum layer 200 deposited on the exposed surface 101, the copper deposited on the exposed surface 101 is formed. The aluminum layer 200 is removed first, and the copper aluminum layer 200 deposited on the surface 21s remains on the surface 21s.

Further, the exposed surface 101 is overetched 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. 3B, a copper-aluminum wiring layer 202L having the same composition as that of the copper-aluminum layer 200 is formed on the opening 21h and the copper-aluminum layer 200 by a sputtering method or a plating method. .. The copper-aluminum wiring layer 202L may be reflowed at 200 to 350 ° C., if necessary, after being formed on the opening 21h and the copper-aluminum layer 200.

As a result, the copper-aluminum layer 200 is substantially heat-treated. Alternatively, a step of heating the copper-aluminum layer 200 at 200 to 350 ° C. may be provided immediately after the copper-aluminum layer 200 is formed. When the copper-aluminum wiring layer 202L is formed by the sputtering method, the copper-aluminum layer 200 and the copper-aluminum wiring layer 202L may be continuously formed by the sputtering method.

Next, as shown in FIG. 3C, the surpluses of the copper-aluminum wiring layer 202L and the copper-aluminum layer 200 on the interlayer insulating layer 21 are removed by chemical mechanical polishing, and the surpluses are formed in the opening 21h. The removed and remaining metal wiring 20 is formed. After that, as shown in FIG. 1A, the interlayer insulating layer 31 is formed on the interlayer insulating layer 21, and further, the metal wiring layer 30 electrically connected to the metal wiring 20 is formed in the interlayer insulating layer 31. Is formed.

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

As shown in FIG. 4A, 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, the interlayer insulating layer 21 is provided with an opening 21h, and the interlayer insulating layer 31 is provided with an opening 31h communicating with the opening 21h. 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 combining, for example, a film forming method such as CVD or sputtering, an etching method by a dry method or a wet 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 side surface 31w of the opening 31h, the surface 21s of the interlayer insulating layer 21 exposed at the opening 21h, and the side surface 21w of the opening 21h. Hydrogen plasma is exposed to the exposed surface 101 of the metal wiring layer 10 exposed at the opening 21h. As a result, when the residue adheres to / remains on the surface 31s, the side surface 31w, the surface 21s, the side surface 21w, and the exposed surface 101, the residue is removed from the surface 31s, the side surface 31w, the surface 21s, the side surface 21w, and the exposed surface 101.

In the hydrogen surface treatment, the same hydrogen plasma as in the manufacturing process of the laminated structure 1a is applied with the intention of evenly exposing the hydrogen plasma along the surface 31s, the side surface 31w, the surface 21s, the side surface 21w, and the exposed surface 101. Alternatively, hydrogen radicals may be exposed by particles in a radical state that do not exhibit ionicity, and for example, a known remote plasma can be adopted.

Next, as shown in FIG. 4C, the oxygen plasma is exposed to the surface 31s, the side surface 31w, the surface 21s, the side surface 21w, and the exposed surface 101. As a result, the surface 31s, the side surface 31w, the surface 21s, the side surface 21w, and the exposed surface 101 are oxidized, and an ultrathin oxide layer is formed on the surface 31s, the side surface 31w, the surface 21s, the side surface 21w, and the exposed surface 101. ..

In the oxygen surface treatment, the oxygen plasma treatment in which the directivity of the plasma gas is relaxed is applied with the intention of evenly exposing the oxygen plasma along the surface 31s, the side surface 31w, the surface 21s, the side surface 21w, and the exposed surface 101. For example, the same oxygen plasma as in the manufacturing process of the laminated structure 1a is applied. Alternatively, oxygen radicals may be exposed by particles in a radical state that do not exhibit ionicity, and for example, a known remote plasma can be adopted.

Next, as shown in FIG. 4D, a copper-aluminum layer 250 is formed on each of the exposed surface 101, the surface 21s, the side surface 21w, the surface 31s, and the side surface 31w by sputtering film formation.

As the sputtering method, a sputtering method in which the directivity of the sputtering particles is improved is applied with the intention of forming the copper-aluminum layer 250 along the exposed surface 101 and the surface 21s, the side surface 21w, the surface 31s and the side surface 31w. For example, a sputtering method that prioritizes anisotropic sputtering over isotropic sputtering is applied.

Next, as shown in FIG. 5A, the surface 31s of the interlayer insulating layer 31, the surface 21s of the interlayer insulating layer 21, and the copper aluminum layer 250 deposited on the exposed surface 101 are physically etched.

In physical etching, plasma obtained by ionizing an inert gas such as Ar, He, or Xe is used as the plasma gas. As the physical etching using this plasma, a sputtering method in which the directivity of plasma ions is improved is applied as in the manufacturing process of the laminated structure 1a.

As a result, the ions in the plasma easily reach the copper-aluminum layer 250 deposited on the surfaces 21s and 31s as well as the copper-aluminum layer 250 deposited on the exposed surface 101, and are deposited on the surfaces 21s and 31s and the exposed surface 101. Both copper-aluminum layers 250 are etched at the same time.

However, since the opening width of the opening 21h is narrow and the thickness of the copper aluminum layer 250 deposited on the surfaces 21s and 31s is thicker than the thickness of the copper aluminum layer 250 deposited on the exposed surface 101, it is deposited on the exposed surface 101. The copper-aluminum layer 250 is removed first. As a result, the copper-aluminum layer 250 deposited on the surfaces 21s and 31s remains on the surface 21s.

Further, the exposed surface 101 is overetched 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. 5B, a copper-aluminum wiring layer 252L having the same composition as that of the copper-aluminum layer 250 is formed on the openings 21h and 31h and the copper-aluminum layer 250 by a sputtering method or a plating method. Will be done. The copper-aluminum wiring layer 252L may be reflowed at 200 to 350 ° C., if necessary, after being formed on the openings 21h and 31h and the copper-aluminum layer 250.

As a result, the copper-aluminum layer 250 is substantially heat-treated. Alternatively, a step of heating the copper-aluminum layer 250 at 200 to 350 ° C. may be provided immediately after the copper-aluminum layer 250 is formed. When the copper-aluminum wiring layer 252L is formed by the sputtering method, the copper-aluminum layer 250 and the copper-aluminum wiring layer 252L may be continuously formed by the sputtering method.

Next, as shown in FIG. 5 (c), the surpluses of the copper-aluminum wiring layer 252L and the copper-aluminum layer 250 on the interlayer insulating layer 31 are removed by chemical mechanical polishing, and are shown in FIG. 1 (b). The laminated structure 2 is formed.

The operation of the present embodiment will be described by taking the laminated structure 1 of FIG. 1A as an example.

In the present embodiment, the oxygen plasma is exposed to the opening 21h of the interlayer insulating layer 21 from which the residue has been removed by the hydrogen plasma. As a result, an ultrathin oxide layer is formed on the side surface 21w of the opening 21h. This oxide layer functions as, for example, an oxidation active layer or a peroxide layer in which the surface layer of the side surface 21w is washed or reduced by hydrogen plasma and then oxidized again by oxygen plasma.

As a result, when the _{copper-aluminum layer 200 containing CuAl 2} is formed on the side surface 21w, a reaction occurs between Al in the copper-aluminum layer 200 and the oxide layer, and between the interlayer insulating layer 21 and the copper-aluminum layer 200. An aluminum oxide layer (AlO _x layer) is formed. This reaction is further promoted by heat-treating the copper-aluminum layer 200 such as a reflow process.

The aluminum oxide layer functions as, for example, a barrier layer for preventing the diffusion of Cu and Al into the interlayer insulating layer 21, and the diffusion of Cu and Al from the metal wiring 20 into the interlayer insulating layer 21 is surely prevented. As a result, the characteristics of the interlayer insulating layer 21 are maintained with high reliability.

Further, the interlayer insulating layer 21 and the oxide layer both have oxygen, and the copper aluminum layer 200 and the oxide layer both have aluminum. As a result, between the copper-aluminum layer 200 and the interlayer insulating layer 21, the oxide layer becomes an adhesive layer, and a high adhesive force between the copper-aluminum layer 200 and the interlayer insulating layer 21 is generated. The same effect is obtained in the laminated structure 2 of FIG. 1 (b).

(Modification example)

FIG. 6 is a schematic cross-sectional view showing a modified example of the manufacturing process of the laminated structure.

In the sputtering film formation of the copper-aluminum layer 200, the sputtering film formation _{may be performed by making the normal line 40n of the sputtering target containing CuAl 2} and the normal line 21n of the interlayer insulating layer 21 non-parallel. At the time of sputtering film formation, the substrate including the laminated structure 1a may be appropriately rotated in a direction parallel to the surface 21s.

The step coverage of the sputtering film at the opening 21h, which is good for rotating the substrate, is further improved. As a result, the copper-aluminum layer 200 comes into close contact with the interlayer insulating layer 21 without interruption and without gaps. As a result, a more reliable metal wiring 20 can be obtained. The modified example may be applied to the manufacturing process of the laminated structure 2a.

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

1, 1a, 2, 2a ... Laminated structure 10, 30 ... Metal wiring layer 10s, 21s, 31s ... Surface 11, 21, 31 ... Interlayer insulation layer 20, 25 ... Metal wiring 20d ... Lower end 20u ... Upper end 21h, 31h ... Openings 21w, 31w ... Side surfaces 25a, 25b ... Wiring part 101 ... Exposed surface 200, 250 ... Copper aluminum layer 202, 252 ... Copper aluminum wiring 202L, 252L ... Copper aluminum wiring layer

Claims (8)

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 in which a part of the surface of the metal wiring layer is exposed is prepared.
The sides of the opening are exposed to oxygen ions and / or oxygen radicals.
A method for forming a metal wiring that forms a copper-aluminum layer along the side surface of the opening by a sputtering method. The method for forming a metal wiring according to claim 1.
A method for forming a metal wiring to which hydrogen ions and / or hydrogen radicals are exposed to the side surfaces before the oxygen ions and / or oxygen radicals containing oxygen gas are exposed to the side surfaces. The method for forming a metal wiring according to claim 1 or 2.
After the copper-aluminum layer is formed on the side surface, the natural oxide film of the metal wiring layer exposed at the opening is removed from the metal wiring layer. The method for forming a metal wiring according to any one of claims 1 to 3.
A method for forming a metal wiring using a Low-k layer as the interlayer insulating layer. The method for forming a metal wiring according to any one of claims 1 to 4.
A method for forming a metal wiring using _two CuAl layers as the copper-aluminum layer. The method for forming a metal wiring according to any one of claims 1 to 5.
A method for forming a metal wiring, wherein 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. The method for forming a metal wiring according to any one of claims 1 to 6.
A method for forming a metal wiring by removing the natural oxide film and then forming a copper-aluminum wiring in the opening through the copper-aluminum layer by a sputtering method or a plating method. The method for forming a metal wiring according to claim 7.
A method for forming a metal wiring in which the components of the copper-aluminum layer are the same as the components of the copper-aluminum wiring.

Images