JP7343407B2 - Metal wiring formation method and metal wiring structure - Google Patents

Description

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

In electronic components such as LSIs, a conductive layer is embedded in an opening such as 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 opening by forming the conductive layer on the opening 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).

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. This low-k material is generally made 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 a conductive layer to an interlayer insulating layer, the dielectric constant of the interlayer insulating layer changes or electrical leakage occurs within the interlayer insulating layer, reducing 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 metal wiring and a metal wiring structure that does not reduce the reliability of an electronic component including metal wiring formed in an opening in an interlayer insulating layer. It is in.

In order to achieve the above object, a method for forming metal wiring according to one embodiment of the present invention is as follows.
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.
By the first sputtering film formation, a nitrogen-containing copper aluminum layer is formed as an initial layer along the side surface of the opening of the interlayer insulating layer.
By the second sputtering film formation, a copper aluminum layer is formed on the side surface via the initial layer.

According to this method of forming metal wiring, a barrier layer is spontaneously formed between the nitrogen-containing copper aluminum layer and the interlayer insulating layer, and a highly reliable metal wiring is formed in the interlayer insulating layer. Ru.

In the above method for forming a metal wiring, the first sputtering film formation may be performed using a sputtering method in which anisotropic sputtering is prioritized over isotropic sputtering, or a normal line of a sputtering target and a normal line of the interlayer insulating layer are A sputtering method may be adopted in which the steps are performed non-parallel.

According to such a method of forming a metal wiring, a nitrogen-containing copper aluminum layer is formed in the opening with good step coverage, and a highly reliable metal wiring is formed in the interlayer insulating layer.

In the above-mentioned method for forming a metal wiring, the initial layer may be formed in the first sputtering film formation using a target containing copper aluminum, while nitrogen is contained in the plasma gas.

According to such a method of forming a metal wiring, a copper aluminum layer containing nitrogen is formed in the opening, a barrier layer is spontaneously formed between the copper aluminum layer containing nitrogen and the interlayer insulating layer, and Highly reliable metal wiring is formed in the interlayer insulating layer.

In the above method for forming metal wiring, a sputtering method in which anisotropic sputtering is prioritized over isotropic sputtering may be adopted as the second sputtering film formation.

According to such a method of forming a metal wiring, a copper aluminum layer is formed in the opening with good step coverage, and a highly reliable metal wiring is formed in the interlayer insulating layer.

In the method for forming metal wiring, the initial layer may be formed so that the initial layer is thinner than the copper aluminum layer.

According to this method of forming metal wiring, a thin copper-aluminum layer containing nitrogen is formed in the opening, so the opening width of the opening does not narrow unnecessarily, and highly reliable metal wiring can be formed in the interlayer insulating layer. is formed.

In the method for forming a metal wiring described above, after the initial layer is formed, the initial layer may be subjected to a heat treatment.

According to such a metal wiring formation method, the formation of a barrier layer between the nitrogen-containing copper aluminum layer and the interlayer insulation layer is promoted, and a highly reliable metal wiring is formed in the interlayer insulation layer. .

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

According to such a method for forming metal wiring, even if a Low-k layer is used as an interlayer insulating layer, the formation of a barrier layer between the nitrogen-containing copper aluminum layer and the interlayer insulating layer is promoted. The function of the interlayer insulating layer is less likely to be impaired.

In the method for forming a metal wiring described above, _two layers of CuAl may be used as the copper aluminum layer.

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

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 a metal wiring, a metal wiring containing copper aluminum is formed even in an opening of the above size.

In the above method for forming a metal wiring, after forming the copper aluminum layer, a copper aluminum wiring may be formed in the opening by a sputtering method or a plating method.

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

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

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

In order to achieve the above object, a metal wiring structure according to one embodiment of the present invention includes a metal wiring layer containing copper, an interlayer insulating layer, a copper aluminum layer containing nitrogen, and a copper aluminum layer.
The interlayer insulating layer is laminated on the metal wiring layer, and has an opening that exposes a part of the surface of the metal wiring layer.
The nitrogen-containing copper aluminum layer is provided along a side surface of the opening in the interlayer insulating layer.
The copper aluminum layer is provided in the opening via the nitrogen-containing copper aluminum layer.

According to such a metal wiring structure, a barrier layer is spontaneously formed between the nitrogen-containing copper aluminum layer and the interlayer insulation layer, and a highly reliable metal wiring is formed in the interlayer insulation layer. .

As described above, according to the present invention, a method for forming metal wiring and a metal wiring structure that do not reduce the reliability of electronic components are 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). 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 as a metal wiring structure, a metal wiring, and a metal wiring in the upper layer of an electronic component (for example, a semiconductor device) including a transistor, a resistor, a capacitor, a memory, etc. 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 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 20 includes a nitrogen-containing copper aluminum (CuAl _x N _y ) layer 200 , a copper aluminum layer 201 , and a copper aluminum wiring 202 . Hereinafter, the copper aluminum layer containing nitrogen will be referred to as a copper aluminum nitride layer 200 in this embodiment. The copper aluminum nitride layer 200 is in contact with the interlayer insulating layer 21 , and the copper aluminum layer 201 is provided between the copper aluminum nitride layer 200 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 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, the copper aluminum layer 201 of the metal wiring 20, and the copper aluminum wiring 202 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. Note that since the copper-aluminum layer 201 and the copper-aluminum wiring 202 are composed of the same components, the boundary (broken line) between the copper-aluminum layer 201 and the copper-aluminum wiring 202 may disappear.

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.

The metal wiring 25 includes a copper aluminum nitride layer 250, a copper aluminum layer 251, and a copper aluminum wiring 252. The copper aluminum nitride layer 250 is in contact with the interlayer insulating layers 21 and 31, and the copper aluminum layer 251 is provided between the copper aluminum nitride layer 250 and the copper aluminum wiring 252. The copper aluminum layer 251 and the copper aluminum wiring 252 are made of the same components. For example, the material of the copper aluminum layer 251 and the copper aluminum wiring layer 25 is a Cu alloy such as CuAl ₂ (CuAl ₂ -θ layer). Therefore, the boundary (broken line) between the copper aluminum layer 251 and the copper aluminum wiring 252 may disappear.

Such a laminated structure 2 is also included in this embodiment.

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

2(a) to 3(c) 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. 2B, sputtering film formation (first sputtering film formation) is performed to form a nitrided film along the surface 21s of the interlayer insulating layer 21, the side surface 21w of the opening 21h, and the exposed surface 101. A copper aluminum layer 200 is formed. For example, a copper aluminum target such as CuAl ₂ (CuAl ₂ -θ layer) is used, and a discharge gas containing nitrogen is used. For example, an inert gas such as Ar, He, Ne, or Xe is used as the discharge gas, and nitrogen (N ₂ ) is added to the discharge gas.

As a result, nitrogen becomes active in the plasma gas, and the copper aluminum nitride layer 200 is formed on the surface 21s, side surface 21w, and exposed surface 101 by so-called reactive sputtering. However, as the opening width of the opening 21h becomes narrower, the thickness of the copper aluminum nitride layer 200 deposited on the surface 21s becomes thicker than the thickness of the copper aluminum nitride layer 200 deposited on the exposed surface 101.

Moreover, in this sputtering film formation, a sputtering method with improved directivity of sputtered particles is applied with the intention of forming the copper aluminum nitride layer 200 along the surface 21s, the side surface 21w, and the exposed surface 101. For example, a sputtering method is applied in which anisotropic sputtering is prioritized over isotropic sputtering.

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. As an example of anisotropic sputtering, a sputtering method such as LTS (Long Through Sputtering) is applied.

However, as the opening width of the opening 21h becomes narrower, it becomes more difficult for sputtered particles to reach the exposed surface 101. is formed with a large thickness.

Next, as shown in FIG. 2C, physical etching is performed on the copper aluminum nitride layer 200 deposited on the surface 21s of the interlayer insulating layer 21 and the exposed surface 101.

In the physical etching, plasma in which an inert gas such as Ar, He, or Xe is discharged is used as the plasma gas. As this physical etching using plasma, a sputter etching method is applied in which the directivity of plasma ions is improved by applying a substrate bias. 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 stacked structure 1a, and plasma processing is performed in a low pressure region (eg, 10E ⁻³ Pa to 10 Pa).

This makes it easier for ions in the plasma to reach the copper aluminum nitride layer 200 deposited on the surface 21s of the interlayer insulating layer 21 as well as the copper aluminum nitride layer 200 deposited on the exposed surface 101. Both deposited copper aluminum nitride layers 200 are etched simultaneously. However, since the copper aluminum nitride layer 200 deposited on the surface 21s is thicker than the copper aluminum nitride layer 200 deposited on the exposed surface 101, the copper aluminum nitride layer 200 deposited on the exposed surface 101 is removed first. , the copper aluminum nitride layer 200 deposited on the surface 21s remains on the surface 21s.

As a result, the thickness of the copper aluminum nitride layer 200 deposited on the surface 21s is reduced, and the copper aluminum nitride layer 200 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.

Thereby, the copper aluminum nitride layer 200 is formed as an initial layer on the surface 21s of the interlayer insulating layer 21 and the side surface 21w of the opening 21h. Note that the thickness of the copper aluminum nitride layer 200 is set to be thinner than the thickness of the copper aluminum layer 201, which will be described later. Thereby, the opening width of the opening 21h is not narrowed unnecessarily, and a predetermined opening width is ensured. For example, the thickness of the copper aluminum nitride layer 200 on the side surface 21w is 1 to 3 nm, and the thickness of the copper aluminum layer 201 is 1 to 4 nm.

Next, as shown in FIG. 3A, by sputtering film formation (second sputtering film formation), a copper aluminum layer is formed on the exposed surface 101, each of the surface 21s and the side surface 21w via the copper aluminum nitride layer 200. 201 is formed.

As the sputtering method, in order to form the copper aluminum layer 201 along the exposed surface 101 and the copper aluminum nitride layer 200, a sputtering method in which the directivity of sputtered particles is improved is applied. For example, a sputtering method is applied in which anisotropic sputtering is prioritized over isotropic sputtering. For example, a sputtering method such as LTS is applied.

Next, as shown in FIG. 3B, a copper-aluminum wiring layer 202L having the same composition as that of the copper-aluminum layer 201 is formed on the opening 21h and the copper-aluminum layer 201 by sputtering or plating. . After the copper-aluminum wiring layer 202L 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.

Thereby, the copper aluminum nitride layer 200, which is the initial layer, is substantially subjected to heat treatment. Alternatively, immediately after forming the copper aluminum nitride layer 200 or immediately after forming the copper aluminum layer 201, a step of heating the copper aluminum nitride layer 200 at 200 to 350° C. may be provided. Note that when forming the copper-aluminum wiring layer 202L by sputtering, the copper-aluminum layer 201 and the copper-aluminum wiring layer 202L may be successively formed by sputtering.

Next, as shown in FIG. 3(c), the surplus portions of the copper-aluminum wiring layer 202L, the copper-aluminum layer 201, and the copper-aluminum nitride layer 200 on the interlayer insulating layer 21 are removed by chemical mechanical polishing. The metal wiring 20 remaining after the surplus is removed is formed in the opening 21h. 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.

4(a) to 5(c) 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, a surface 31s of the interlayer insulating layer 31, a surface 21s of the interlayer insulating layer 21 exposed in the opening 21h, a side surface 31w of the opening 31h, a side surface 21w of the opening 21h, A copper aluminum nitride layer 250 is formed along the exposed surface 101 of the metal wiring layer 10 exposed in the opening 21h.

Here, as the sputtering method, a sputtering method with improved directivity of sputtered particles 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. Here, the thickness of the copper aluminum nitride layer 250 deposited on the surface 31s of the interlayer insulating layer 31 and the surface 21s of the interlayer insulating layer 21 is thicker than the thickness of the copper aluminum nitride layer 250 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 nitride layer 250 deposited on the surface 31s of the interlayer insulating layer 31 is the same as the thickness of the copper nitride layer 250 deposited on the surface 21s of the interlayer insulating layer 21. It is formed thicker than the thickness of the aluminum layer 250.

Next, as shown in FIG. 4C, for example, a layered structure 1a is formed on the copper aluminum nitride layer 250 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. Similar to the process, physical etching with improved directionality is performed.

As a result, the thickness of the copper aluminum nitride layer 250 deposited on the surfaces 31s and 21s is reduced, and the copper aluminum nitride layer 250 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 copper aluminum layer is formed on the exposed surface 101, the surface 21s, the side surface 21w, the surface 31s, and the side surface 31w via the copper aluminum nitride layer 250 by sputtering film formation. 251 is formed.

As the sputtering method, a sputtering method with improved directivity of sputtered particles is applied in order to form the copper aluminum layer 251 along the exposed surface 101 and the copper aluminum nitride layer 250. For example, a sputtering method is applied in which anisotropic sputtering is prioritized over isotropic sputtering. For example, a sputtering method such as LTS is applied.

Next, as shown in FIG. 5B, a copper-aluminum wiring layer 252L having the same composition as that of the copper-aluminum layer 251 is formed on the opening 21h and the copper-aluminum layer 251 by sputtering or plating. . After the copper-aluminum wiring layer 252L is formed on the opening 21h and the copper-aluminum layer 251, a reflow treatment at 200 to 350° C. may be performed as necessary.

When forming the copper-aluminum wiring layer 252L by sputtering, the copper-aluminum layer 251 and the copper-aluminum wiring layer 252L may be successively formed by sputtering.

As a result, the copper aluminum nitride layer 250, which is the initial layer, is substantially subjected to heat treatment. Alternatively, immediately after forming the copper aluminum nitride layer 250 or immediately after forming the copper aluminum layer 251, a step of heating the copper aluminum nitride layer 250 at 200 to 350° C. may be provided.

Next, as shown in FIG. 5C, the surplus portions of the copper-aluminum wiring layer 252L, the copper-aluminum layer 251, and the copper-aluminum nitride layer 250 on the interlayer insulating layer 31 are removed by chemical mechanical polishing. The metal wiring 25 remaining after removing the surplus is formed in the opening 21h.

The operation of this embodiment will be explained using the laminated structure 1 of FIG. 1(a) as an example.

In the present embodiment, in the metal wiring 20, since the copper aluminum nitride layer 200 in contact with the interlayer insulating layer 21 is made of nitride (CuAl _x N _y ), at the interface between the interlayer insulating layer 21 and the copper aluminum nitride layer 200, A reaction between nitrogen in the copper aluminum nitride layer 200 and oxygen in the interlayer insulating layer 21 progresses. This reaction is promoted by heating the copper aluminum nitride layer 200 and the interlayer insulating layer 21, for example, by reflow treatment or the like.

As a result, at the interface between the copper aluminum nitride layer 200 and the interlayer insulating layer 21, for example, an extremely thin aluminum oxynitride layer represented by the chemical formula Al _x' O _y' N _z' is spontaneously formed. . Therefore, the copper aluminum nitride layer 200, which is a nitride, and the aluminum oxynitride layer, which is a nitride oxide, are interposed between the copper aluminum layer 201 and the interlayer insulating layer 21, and the copper aluminum layer 201 ( Alternatively, metal diffusion from the copper-aluminum wiring 202) to the interlayer insulating layer 21 is more reliably prevented. Thereby, the characteristics of the interlayer insulating layer 21 are maintained with high reliability.

Furthermore, the aluminum oxynitride layer and the copper aluminum nitride layer 200 both contain aluminum and nitrogen, and the aluminum oxynitride layer and the interlayer insulating layer 21 both contain oxygen. As a result, the aluminum oxynitride layer functions as an adhesion layer between the copper aluminum nitride layer 200 and the interlayer insulation layer 21, and high adhesion between the copper aluminum nitride layer 200 and the interlayer insulation layer 21 is achieved. Occur.

Furthermore, since both the copper aluminum nitride layer 200 and the copper aluminum layer 201 contain Cu and Al, high adhesion can be obtained between the copper aluminum nitride layer 200 and the copper aluminum layer 201 as well. Further, the copper-aluminum layer 201 and the copper-aluminum wiring 202 have the same composition.

Therefore, the metal wiring 20 contacts the interlayer insulating layer 21 with high adhesion. Similar effects can be obtained in the laminated structure 2 shown in FIG. 1(b).

(Modified example)

FIG. 6 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 nitride layer 200 and the copper aluminum layer 201, the sputtering film formation may be performed with the normal 40n of the sputtering target containing CuAl ₂ and the normal 21n of the interlayer insulating layer 21 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.

This is good for rotating the substrate, and the step coverage of the sputtered film in the opening 21h is further improved. As a result, the copper aluminum nitride layer 200 adheres to the interlayer insulating layer 21 more seamlessly and without gaps, and the copper aluminum layer 201 adheres to the exposed surface 101 and the copper aluminum nitride layer 200 more seamlessly and without gaps. We will be in close contact. As a result, a more reliable metal wiring 20 can be obtained. 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, 30...Metal wiring layer 10s, 21s, 31s...Surface 11, 21, 31...Interlayer insulating layer 20, 25...Metal wiring 20d...Lower end 20u...Upper end 21h, 31h... Opening 21w, 31w...Side surface 25a, 25b...Wiring portion 101...Exposed surface 200, 250...Copper aluminum nitride layer 201, 251...Copper aluminum layer 202, 252...Copper aluminum wiring 202L, 252L...Copper aluminum wiring layer

Claims (12)

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;
forming a nitrogen-containing copper aluminum layer as an initial layer along the side surface of the interlayer insulating layer by first sputtering deposition;
A method for forming a metal wiring, comprising forming a copper aluminum layer on the side surface via the initial layer by second sputtering film formation. A method for forming a metal wiring according to claim 1, comprising:
As the first sputtering film formation, a sputtering method in which anisotropic sputtering is prioritized over isotropic 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. Adopting a metal wiring formation method. A method for forming a metal wiring according to claim 1 or 2, comprising:
A method for forming a metal wiring, wherein the first sputtering film is formed by using a target containing copper aluminum, and forming the initial layer while making the plasma gas contain nitrogen. A method for forming a metal wiring according to any one of claims 1 to 3, comprising:
A method for forming a metal wiring, in which a sputtering method in which anisotropic sputtering is prioritized over isotropic sputtering is adopted as the second sputtering film formation. A method for forming a metal wiring according to any one of claims 1 to 4, comprising:
A method for forming a metal wiring, comprising forming the initial layer so that the thickness of the initial layer is thinner than the thickness of the copper aluminum layer. A method for forming a metal wiring according to any one of claims 1 to 5, comprising:
After the initial layer is formed, the initial layer is subjected to heat treatment. A method for forming a metal wiring according to any one of claims 1 to 6, 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 7, 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 8, 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 9, comprising:
A method for forming a metal wiring, wherein after forming the copper-aluminum layer, a copper-aluminum wiring is formed in the opening by a sputtering method or a plating method. The method for forming metal wiring according to claim 10,
The composition of the copper-aluminum wiring is the same as the composition of the copper-aluminum layer. A method for forming a metal wiring. a metal wiring layer containing copper;
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;
a nitrogen-containing copper aluminum layer provided along a side surface of the opening of the interlayer insulating layer;
a copper aluminum layer provided on the side surface of the opening via the nitrogen-containing copper aluminum layer.

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