JP4065019B6 - Semiconductor device, manufacturing method thereof, and sputtering target material used in the manufacturing method - Google Patents

Description

  The present invention relates to a semiconductor device in which wiring is applied to an insulating film, a manufacturing method thereof, and a sputtering target material used in the manufacturing method.

In order to construct an electronic device such as a silicon (Si) semiconductor device such as an integrated circuit (IC) or a liquid crystal display device (LCD), it is necessary to form wiring from a material having low resistance and high conductivity. In configuring a silicon large-scale integrated circuit (VLSI) or the like, a fine wiring technique is required to increase the degree of integration. Recently, copper (Cu) having lower resistance than aluminum alloy and higher migration resistance is used for wiring for silicon VLSI and LCD (see Patent Document 1 below).
JP-A-5-47760

However, since the copper forming the wiring diffuses into the surrounding insulating film, a layer such as tantalum (Ta) or its nitride (TaN) is formed as a barrier layer (barrier layer) that suppresses the diffusion of Cu. It is necessary (see Patent Document 2 below).
JP 2001-44156 A

  On the other hand, in a semiconductor device such as a large scale integrated circuit (LSI), in order to increase the degree of integration, it is necessary to reduce the wiring width. However, as the wiring width is reduced, the high resistance occupies the wiring width. When the ratio of the thickness of a certain barrier layer is increased and the barrier layer is provided as in Patent Document 2 described above, there is a problem that the effective resistance of the wiring increases.

Recently, a barrier layer such as Ta or TaN is not intentionally formed as in the prior art described above. For example, an alloy of Cu and manganese (Mn) formed on an insulating film (Cu · Mn alloy), etc. A technique is disclosed in which a barrier layer is formed in a self-aligned manner between a copper wiring and an insulating film by heating a Cu alloy film made of a Cu alloy (see Patent Document 3 below).
JP 2005-277390 A

However, the conventional barrier layer formed using a Cu alloy has the following problems.
(1) Sufficient barrier property cannot be secured for diffusion of Cu from the wiring side, and Cu diffuses to the insulating film side, so that insulation of the insulating film cannot be secured.
(2) Si on the insulating film side diffuses to the wiring side due to mutual diffusion, and the resistance on the wiring side becomes high.
(3) Since the adhesion between the barrier layer and the insulating film is poor, a semiconductor device that is excellent in operation reliability over a long period cannot be constructed.
The above problems are caused by the fact that the configuration of the barrier layer that improves the adhesion with the insulating film and sufficiently provides a barrier action against the diffusion of Cu and Si is not clear. Conceivable.

  The present invention has been proposed in view of the above, and by ensuring that the barrier layer has a sufficient barrier action against Cu diffusion from the wiring body side and Si diffusion from the insulating film side, ensuring insulation of the insulating film, or Semiconductor device which can realize low resistance of wiring and can improve the adhesion between the barrier layer and the insulating film and has excellent operation reliability over a long period of time, its manufacturing method and its manufacturing method It aims at providing the target material for sputtering used for this.

In order to achieve the above object, (1) according to a first aspect of the present invention, an insulating film containing silicon (Si) is provided in a semiconductor device in which wiring is applied to the insulating film, and the insulating film is provided. A wiring main body made of copper (Cu) formed in the groove-shaped opening, and formed between the insulating film and the wiring main body, and the atomic concentration of manganese (Mn) is maximized at the central portion in the thickness direction. And a barrier layer made of a Mn-based oxide.
(2) According to a second aspect of the present invention, in the configuration of the invention described in the above item (1), the barrier layer contains Cu.
(3) According to a third invention, in the configuration of the invention described in the above item (2), the atomic concentration of Cu contained in the barrier layer decreases monotonously from the wiring body side toward the insulating film side. It is what.
(4) According to a fourth aspect of the present invention, in the configuration of the invention described in the above item (3), the atomic concentration of Cu contained in the barrier layer is equal to or lower than the atomic concentration of Mn in the central portion in the thickness direction of the barrier layer. It is what.
(5) According to a fifth aspect of the present invention, in a semiconductor device in which a wiring is provided on an insulating film, an insulating film containing silicon (Si) and a copper formed in a groove-shaped opening provided in the insulating film (Cu) formed between the wiring main body and the wiring main body and the insulating film, the atomic concentration of Cu decreases monotonously from the wiring main body side to the insulating film side, and from the insulating film side to the wiring main body side. It is made of an oxide containing Cu, Si, and Mn, in which the atomic concentration of Si monotonously decreases, and the atomic concentration of Mn is maximized in a region where the atomic concentration of Cu and the atomic concentration of Si are substantially equal. And a barrier layer.
(6) According to a sixth aspect of the present invention, in the configuration of the invention described in the above item (5), the barrier layer has an atomic concentration of Mn in a region where the atomic concentrations of Cu and Si in the interior are substantially equal, The atomic concentration of Cu or Si is set to be twice or more.
(7) In a seventh aspect of the invention, in the configuration of the invention described in any one of the above items (1) to (6), the barrier layer has a layer thickness of 1 nm or more and a groove width of the opening. 1/5 or less and 10 nm or less.
(8) According to an eighth aspect of the invention, in the configuration of the invention described in any one of the above items (1) to (7), the barrier layer is made of an amorphous material.
(9) According to a ninth invention, in the configuration of the invention described in any one of the above items (1) to (8), ionization is performed bivalently or trivalently on the side of the wiring body in contact with the barrier layer. Mn is present.
(10) According to a tenth aspect of the present invention, in the method of manufacturing a semiconductor device in which an insulating film is provided with a wiring, a step of providing a groove-shaped opening in an insulating film containing silicon (Si), and an inner periphery of the opening A copper alloy film forming step of forming a copper alloy film containing manganese (Mn) and copper (Cu) on the surface, a step of filling Cu in the opening in which the copper alloy film is formed and forming a copper buried layer, and a heat treatment A barrier layer is formed between the copper alloy film and the insulating film, and the copper alloy film is integrated with Cu of the copper buried layer to form a wiring body, and the barrier layer Is made of a Mn-based oxide that maximizes the atomic concentration of Mn at the center in the thickness direction.
(11) An eleventh aspect of the invention is a method of manufacturing a semiconductor device in which a wiring is provided on an insulating film, the step of providing a groove-shaped opening in an insulating film containing silicon (Si), and the inner periphery of the opening A copper alloy film forming step of forming a copper alloy film containing manganese (Mn) and copper (Cu) on the surface, a step of filling Cu in the opening in which the copper alloy film is formed and forming a copper buried layer, and a heat treatment A barrier layer is formed between the copper alloy film and the insulating film, and the copper alloy film is integrated with Cu of the copper buried layer to form a wiring body, and the barrier layer Shows that the atomic concentration of Cu decreases monotonously from the wiring body side toward the insulating film side, the atomic concentration of Si decreases monotonously from the insulating film toward the wiring body side, and the atomic concentration of Cu and the atomic concentration of Si Where the atomic concentration of Mn is maximized in a region where In which a formed of an oxide containing Si and Mn.
(12) In a twelfth aspect of the present invention according to the structure described in the above item (10) or (11), in the heat treatment step, the heat treatment inevitably contains pure inert gas or oxygen inevitably containing oxygen. 75 vol. (13) The thirteenth invention is the above-described heat treatment in the constitution of the invention described in the above item (10) or (11). In the process, the heat treatment inevitably includes nitrogen gas or hydrogen gas containing oxygen, or oxygen at a maximum of 75 vol. This is carried out in an air stream composed of nitrogen gas or hydrogen gas contained at a ratio of ppm.
(14) In the fourteenth aspect of the invention, in the configuration of the invention according to any one of the paragraphs (10) to (13), the heat treatment is performed at a temperature of 150 ° C. or higher and 600 ° C. or lower in the heat treatment step. It is what I did.
(15) In the fifteenth aspect of the invention, the heat treatment is performed at a temperature of 150 ° C. or higher and 450 ° C. or lower in the configuration of the invention described in any one of the items (10) to (13). It is what I did.
(16) In accordance with the first 6 is a method of manufacturing a semiconductor device according to any one of the above (10) from section (15) section, the formation of the copper alloy film in the copper alloy film forming step, The sputtering target material is subjected to sputtering.
(17) The seventeenth invention is the sputtering target material according to item (16), wherein sputtering is performed to form a copper alloy film, and copper (Cu) as a main component and manganese as an essential element (Mn) and unavoidable impurities inevitably remaining in the remaining Cu excluding the essential elements, and the unavoidable impurities include lithium (Li) constituting the first group, beryllium constituting the second group ( Be), calcium (Ca) and magnesium (Mg), boron (B) constituting the third group, gallium (Ga) and aluminum (Al), silicon (Si) constituting the fourth group, constituting the fifth group Antimony (Sb), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), Thorium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), palladium (Pd), hafnium (Hf), tantalum (Ta), tungsten (W), Main transition metal elements of rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt) and gold (Au), lanthanum (La), cesium (Ce) and samarium (Sm) constituting the seventh group ), Gadori two um (Gd), terbium (Tb), Disperse propidium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (in each lanthanide of Lu) transition When it is one of metal elements and thorium (Th) constituting the eighth group, the total content of the inevitable impurities is In the atomic concentration is to 0.1% or less of the entire target material.
(18) An eighteenth aspect of the invention is the sputtering target material according to the item (16), in which sputtering is performed to form a copper alloy film, and copper (Cu) as a main component and manganese as an essential element (Mn) and unavoidable impurities that inevitably remain in the remaining Cu excluding the essential elements. The unavoidable impurities are lithium (Li), beryllium (Be), calcium (Ca), magnesium (Mg). Boron (B), gallium (Ga), aluminum (Al), silicon (Si), antimony (Sb), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe) , Cobalt (Co), nickel (Ni), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ru Ni (Ru), Palladium (Pd), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt), Gold (Au), lanthanum (La), cesium (Ce), samarium (Sm), Gadori two Umm (Gd), terbium (Tb), disk dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium ( In the case of any of Yb), lutesium (Lu), and thorium (Th), the total content of the inevitable impurities is set to an atomic concentration of 0.1% or less of the entire target material.
(19) The nineteenth invention is the target according to any one of the above items (16) to (18), wherein the content of Mn as the essential element is set to an atomic concentration. 0.5% or more and 20% or less of the entire material.

  According to the first invention or the tenth invention, a barrier layer made of a Mn-based oxide that maximizes the atomic concentration of Mn at the center of the layer thickness between the insulating film and the wiring body, that is, the layer thickness A barrier layer made of a Mn-based oxide in which Mn is concentrated is provided at the center of the substrate. This barrier layer is a thermally stable and structurally dense layer because of its low formation energy, and is effective in suppressing diffusion. For this reason, it comes to have a favorable barrier property with respect to the diffusion of Cu from the wiring body side, and the insulating property of the insulating film can be made excellent. Further, it has a good barrier property against the diffusion of Si from the insulating film side, and the wiring body can have a low resistance. Accordingly, a low-power-consumption semiconductor device can be provided with wiring that can prevent leakage of element operating current with low resistance.

  According to the second invention, since the barrier layer is a film containing Cu, the atomic concentration distribution is not isolated between the barrier layer and the wiring main body containing Cu as a main component. Since the concentration continuously changes, it is possible to improve the adhesion with the Cu film forming the wiring body that is formed in contact with the surface of the barrier layer, and the reliability of the semiconductor device over a long period of time. It can be made excellent.

  According to the third invention, since the atomic concentration of Cu in the barrier layer is monotonously decreased from the side of the wiring main body containing Cu as a main component toward the insulating film side, The atomic concentration distribution is not isolated from the wiring main body containing Cu as the main component, and since the Cu concentration changes continuously, the adhesion to the Cu film forming the wiring main body can be further improved. Thus, the semiconductor device can be excellent in operation reliability over a long period of time.

  Further, according to the fourth invention, since the atomic concentration of Cu contained in the barrier layer is set to be equal to or lower than the atomic concentration of Mn at the central portion in the thickness direction of the layer, the main constituent element of the barrier layer is Mn, Since the Mn has a strong bonding force with oxygen, it becomes a Mn oxide with a slow diffusion, and the barrier layer is formed from an oxide mainly composed of the Mn. For this reason, a barrier layer exhibits the outstanding barrier property with respect to the spreading | diffusion of Cu from the wiring main body side.

In the fifth invention or the eleventh invention, a barrier layer made of an oxide containing Cu, Si and Mn is formed between the wiring body and the insulating film, and the barrier layer is formed from the wiring body side to the insulating film. In the region where the atomic concentration of Cu decreases monotonously toward the side, the atomic concentration of Si decreases monotonously from the insulating film toward the wiring body, and the atomic concentration of Mn is substantially equal to the atomic concentration of Cu and Si. Since the concentration is maximized, the barrier layer is a thermally stable and structurally dense oxide layer. For this reason, the barrier layer has an effective configuration for suppressing diffusion, has a good barrier property against Cu diffusion from the wiring body side, and has a better insulating property of the insulating film. can do. Further, it has a good barrier property against Si diffusion from the insulating film side, and the wiring body can be made to have a lower resistance. Therefore, a wiring that can prevent leakage of element operating current with low resistance can be provided, and a semiconductor device with much lower power consumption can be obtained.
Further, since the atomic concentration of Cu in the barrier layer is monotonously decreased from the side of the wiring main body mainly composed of Cu toward the insulating film side, the wiring main body mainly composed of the barrier layer and Cu Since the atomic concentration distribution is not isolated between the two and the Cu concentration continuously changes, the adhesion with the Cu film forming the wiring body can be further improved, and the semiconductor device can be operated over a long period of time. The reliability can be improved.
Also, the barrier layer becomes an oxide mainly containing Si and Mn due to diffusion reaction at the interface with the insulating film, and the atomic concentration of Si in the barrier layer monotonously from the insulating film toward the wiring body side. It is decreasing. Therefore, the Si composition distribution from the insulating film is not a steep discontinuous distribution at the interface with the barrier layer, but a continuous distribution. For this reason, the interface strength between the insulating film and the barrier layer can be increased, and the adhesion with the insulating film can be improved. From this point of view, the semiconductor device should have excellent operation reliability over a long period of time. it can.
As described above, in the fifth or eleventh invention, it is possible to reduce the power consumption of the semiconductor device by reducing the resistance of the wiring body and improving the insulating properties of the insulating film. By improving the adhesion between the barrier layer and the adhesion between the barrier layer and the insulating film, it is possible to make the semiconductor device excellent in operation reliability over a long period of time.

  In the sixth aspect of the invention, the atomic concentration of Mn in the region of the barrier layer where the atomic concentrations of Cu and Si are substantially equal is set to be twice or more the atomic concentration of Cu or Si. If the oxide is mainly composed of Si, the oxide continues to grow continuously. However, since the oxide is composed mainly of Mn, the growth of the barrier layer follows the logarithm rule of time. The reason why the logarithmic rule is followed is considered to be due to the following reason. That is, the Mn-based oxide in the barrier layer has a dense structure and slow diffusion, so that the oxide growth does not occur by normal thermal diffusion, and the free electrons associated with the Mn atoms are opposite to the barrier layer. The tunnel moves to the side (insulating film side) and ionized Mn is present on the side of the wiring body in contact with the barrier layer, and an electric field is formed on both sides of the barrier layer 7 in the process of formation. This electric field accelerates the diffusion of Mn ions in the barrier layer, thereby causing growth of an oxide mainly composed of Mn. Such growth behavior causes the growth rate of the barrier layer to follow the logarithm rule of time. As a result, the thickness of the barrier layer is rapidly increased at the initial stage of formation, and the rate of change of the thickness is slowed over time, so that the growth is suppressed and does not grow beyond several nm. For this reason, the barrier layer is a thermally stable and structurally dense Mn oxide film, which is more effective for suppressing diffusion. Therefore, the barrier action of the barrier layer against the diffusion of Cu from the wiring body side and the diffusion of Si from the insulating film side can be further improved, and the insulating properties of the insulating film and the low resistance of the wiring can be further improved. .

  In the seventh invention, since the barrier layer has a thickness of 1 nm or more and is 1/5 or less of the groove width of the opening so as to ensure the thickness of the barrier layer, the diffusion of Cu from the wiring body side is ensured. In addition, the barrier action of the barrier layer against the diffusion of Si from the insulating film side is ensured. At the same time, since the thickness of the barrier layer is set to 10 nm or less at the maximum, it is possible to reliably prevent adverse effects such as the wiring body being narrowed by the barrier layer and the effective electrical resistance of the wiring being increased. Therefore, the insulating property of the insulating film and the low resistance of the wiring can be obtained more reliably.

  In the eighth invention, since the barrier layer is amorphous, it is possible to suppress abnormal diffusion of Cu and Si through the grain boundary. Therefore, the barrier action of the barrier layer is improved, and the insulating properties of the insulating film and the low resistance of the wiring can be reliably maintained.

  Further, according to the ninth aspect, since Mn ionized bivalently or trivalently exists on the side of the wiring body in contact with the barrier layer, a positive charge is present on the side of the wiring body adjacent to the barrier layer. An electric field is formed between the insulating films facing each other with a layer interposed therebetween. The electric field formed on both sides of the barrier layer attracts the wiring body and the insulating film to the barrier layer, so that the effect of improving the adhesion at the interface can be obtained, and the semiconductor device can be operated reliably over a long period of time. It can be made excellent.

  Further, according to the twelfth invention, in the heat treatment step, the heat treatment is performed with pure inert gas or oxygen which inevitably contains oxygen at a maximum of 75 vol. Since it was performed in an inert gas containing a ratio of ppm, alloy elements such as Mn that diffused and moved to the surface of the wiring main body without being involved in the formation of the barrier layer contained a trace amount contained in an appropriate amount in the inert gas. It is oxidized with oxygen to form an oxide on the surface of the wiring body, and disappears from the inside of the wiring body in the form of a surface oxide of the wiring body. Accordingly, the wiring resistance is substantially equal to that of pure Cu, and a low-resistance wiring main body can be obtained.

  According to the thirteenth invention, in the heat treatment step, the heat treatment is inevitably performed with nitrogen gas or hydrogen gas containing oxygen inevitably, or oxygen at a maximum of 75 vol. It was carried out in nitrogen gas or hydrogen gas containing at a ratio of ppm. This nitrogen gas or hydrogen gas does not react with copper like the inert gas. When heat treatment is performed in this nitrogen gas or hydrogen gas, alloy elements such as Mn that have diffused and moved to the surface of the wiring body without being involved in the formation of the barrier layer are the same as in the case of heat treatment in an inert gas. Oxidized with a small amount of oxygen contained in a nitrogen gas or hydrogen gas to form an oxide on the surface of the wiring body, and disappear from the inside of the wiring body in the form of a surface oxide of the wiring body. Accordingly, the wiring resistance is substantially equal to that of pure Cu, and a low-resistance wiring main body can be obtained. In addition, since low-cost nitrogen gas or hydrogen gas is used, heat treatment can be performed at low cost.

  In the fourteenth invention, since the heat treatment in the heat treatment step is performed at a temperature of 150 ° C. or more and 600 ° C. or less, the barrier layer can have a specific configuration according to the present invention, and the resistance of the wiring body can be reduced. In addition, various effects such as an improvement in the insulating properties of the insulating film and an improvement in the adhesion to the wiring body and the insulating film can be brought about.

  In the fifteenth aspect, since the heat treatment in the heat treatment step is performed at a temperature of 150 ° C. or higher and 450 ° C. or lower, the amorphization of the barrier layer can be stably formed.

  According to the seventeenth invention, the sputtering target material used for forming the copper alloy film is composed of copper (Cu) as a main component, manganese (Mn) as an essential element, and the remainder excluding the essential element. Inevitable impurities remaining in Cu, and if the inevitable impurities are any of the elements specified as the first group to the eighth group, the total content of the inevitable impurities for each group Since the atomic concentration is 0.1% or less of the entire Cu alloy, the wiring body formed from the sputtering target material has low resistance and good conductivity, and a low power consumption semiconductor device can do.

  According to the eighteenth aspect of the invention, the sputtering target material used for forming the copper alloy film includes copper (Cu) as a main component, manganese (Mn) as an essential element, and the remainder excluding the essential element. If the inevitable impurities are inevitably remaining in Cu, and the inevitable impurities are any of the specified elements, the total content of the inevitable impurities is set to an atomic concentration of 0.1% of the entire Cu alloy. Therefore, the wiring body formed from the sputtering target material has low resistance and good conductivity, and a semiconductor device with low power consumption can be obtained.

That is, (a) When an inevitable impurity having a higher free energy for forming an oxide than SiO ₂ and a high bonding reactivity with oxygen is present in the Cu alloy film, the inevitable impurity is easily bonded to oxygen. In the 17th and 18th aspects of the present invention, this unavoidable impurity is identified and used as a sputtering target material. Since it is defined so that it is hardly included, the wiring body can be made of a low resistance and good conductivity.
Further, (b) when inevitable impurities having a diffusion coefficient in Cu smaller than the self-diffusion coefficient of Cu are present in the Cu alloy film, the inevitable impurities remain in Cu due to slow diffusion in Cu. However, in the seventeenth and eighteenth aspects of the present invention, this inevitable impurity is specified and hardly included in the sputtering target material. Thus, the wiring main body can be made of a low resistance and good conductivity.
In addition, (c) when inevitable impurities forming an intermetallic compound with Cu are present in the Cu alloy film, the inevitable impurities are finally taken into the wiring body to increase the electrical resistance. In the seventeenth and eighteenth inventions, the inevitable impurities are specified and specified so as to be hardly included in the sputtering target material, so that the wiring body can be made low resistance and good conductivity.
Further, (d) if inevitable impurities forming an intermetallic compound with Mn are present in the Cu alloy film, the inevitable impurities are finally taken into the wiring body to increase the electrical resistance. In the seventeenth and eighteenth inventions, the inevitable impurities are specified and specified so as to be hardly included in the sputtering target material, so that the wiring body can be made low resistance and good conductivity.

  In the seventeenth and eighteenth inventions, since manganese (Mn) as an essential element is included in the sputtering target material, the Cu alloy film formed from the sputtering target material is obtained by heat treatment. The barrier layer becomes a Mn-based oxide film, and this Mn-based oxide film can be a good barrier layer against the diffusion of Cu from the wiring body side, and can improve the adhesion with the insulating film. In addition, low power consumption and improved reliability of the semiconductor device can be realized.

  In the nineteenth aspect of the invention, the Mn content as an essential element of the sputtering target material is set to an atomic concentration within a suitable range of 0.5% or more and 20% or less of the entire target material. And a barrier layer having excellent barrier properties can be formed. When the Mn content is 0.5% or less, the amount of Mn required to form the barrier layer is small, so that only a barrier layer having a thickness of 1 nm or less is formed at a part of the interface, Interfacial adhesion cannot be secured, and if it is 20% or more, the amount of Mn is too large, so that the thickness of the barrier layer becomes 10 nm or more, the ratio of the thickness of the barrier layer increases, and the effective wiring Resistance will increase.

  Embodiments of the present invention will be described in detail with reference to the drawings. First, the first embodiment and examples thereof will be described.

  1A and 1B are explanatory views schematically showing a manufacturing procedure and configuration of a semiconductor device according to the present invention. FIG. 1A shows the first half of the manufacturing procedure and FIG. 1B shows the second half of the manufacturing procedure. As shown in FIG. 1B, the wiring 2 provided in the semiconductor device 1 of the present invention includes an insulating film 3 containing silicon (Si) and a groove-like opening 4 provided in the insulating film 3. The wiring body 8 made of copper (Cu) (the symbol in parentheses indicates an element symbol) and the barrier layer 7 formed between the wiring body 8 and the insulating film 3 are formed. .

  The barrier layer 7 is configured as a Mn-based oxide film that maximizes the atomic concentration of manganese (Mn) at the center in the thickness direction, as shown on the right side of FIG. Cu contains, and the atomic concentration of Cu monotonously decreases from the wiring body 8 side toward the insulating film 3 side facing the wiring body 8. Furthermore, Mn ionized bivalently or trivalently exists on the side of the wiring body 8 in contact with the barrier layer 7.

As shown in FIG. 1A, the semiconductor device 1 is manufactured by first providing a groove-like opening 4 in an insulating film 3 containing Si, and then forming manganese (Mn) on the inner peripheral surface of the opening 4. A copper alloy film (Cu alloy film) 5 containing copper (Cu) is formed, and then Cu is embedded in the opening 4 where the Cu alloy film 5 is formed to form a Cu buried layer 6. Then, by performing heat treatment, the Cu alloy film 5 is integrated with Cu of the Cu buried layer 6 to become the wiring body 8, and the barrier layer 7 (see FIG. 1B) is formed between the Cu alloy film 5 and the insulating film 3. ) To form the semiconductor device 1 of the present invention having the wiring 2 as shown in FIG.
The heat treatment may be performed after the Cu alloy film 5 and the Cu buried layer 6 are formed as described above, or may be performed at the stage where the Cu alloy film 5 before Cu is buried is formed. Good. When heat treatment is performed at the stage of forming the Cu alloy film 5 before embedding Cu, the surface side of the Cu alloy film 5 is changed to a surface layer mainly composed of Cu by the heat treatment, and Cu is embedded in the surface layer. The surface layer and the embedded Cu integrally form a wiring body.

  The wiring structure configured based on the Cu alloy film 5 according to the present invention can be formed on the flat insulating film 3, but a wiring groove (opening 4) opened to provide wiring in the insulating film 3. For example, a damascene type wiring can be used effectively by utilizing holes for conducting and connecting wirings to each other. Hereinafter, each part will be described in order.

(Insulating film 3)
The insulating film 3 is, for example, a silicon dioxide (SiO ₂ ) film containing Si and oxygen (O) provided on a silicon (Si) substrate, a silicon oxynitride (SiON) film, and silicon oxide fluoride (SiO ₂ ). SiOF) film, which is a silicon oxide carbide (SiOC) film. The insulating film 3 may be formed as an insulating film in the multilayer wiring, that is, an interlayer insulating film.
The insulating film 3 may be formed by stacking films made of different materials in multiple layers. For example, a multilayer film in which a silicon nitride (SiN) film and a SiO ₂ film are stacked may be used. When an insulating film made of a multilayer film is used, the surface layer of the insulating film 3 in contact with the Cu alloy film 5 is preferably a film containing Si and oxygen (O) as described above.

(Cu alloy film 5)
The alloy element contained in the Cu alloy film 5 deposited on the surface of the insulating film 3 is preferably an element having a diffusion coefficient in Cu larger than the self-diffusion coefficient of Cu and a large free energy for forming an oxide. For example, manganese (Mn), zinc (Zn), germanium (Ge), strontium (Sr), silver (Ag), cadmium (Cd), tin (Sn), indium (In), barium (Ba), praseodymium (Pr) ), Neodymium (Nd). These elements are easily combined with oxygen in the insulating film 3 and oxygen gas contained in a trace amount during heat treatment in the barrier layer 7 to form an oxide, and have good barrier properties against Cu diffusion from the wiring body 8 side. Thus, the insulating property of the insulating film 3 can be improved. Further, it has a good barrier property against the diffusion of Si from the insulating film 3 side, and the wiring body 8 can have a low resistance. Examples of the Cu alloy film 5 suitable for the present invention include a Cu · Mn alloy film.

  The content of the element forming an alloy with Cu inside the Cu alloy film 5 is preferably 0.5% or more and 20% or less in terms of atomic concentration. Within this atomic concentration range, for example, a Cu · Mn alloy film 5 (Cu alloy film 5) containing Mn is obtained by sputtering a target material made of a Cu · Mn alloy containing 7% Mn in atomic concentration. .

The Cu alloy film 5 can be formed on the insulating film made of, for example, SiO ₂ by high frequency sputtering. Moreover, it can form by physical deposition methods, such as an ion plating method and a laser ablation method. Further, it can be formed by a general chemical vapor deposition (CVD) method. Regardless of the means for forming, the temperature at which the Cu alloy film 5 is formed on the insulating film 3 is 100 ° C. or lower, preferably 80 ° C. or lower. When the Cu alloy film 5 is formed at a high temperature exceeding 100 ° C., the oxidation reaction proceeds remarkably due to contact with the underlying insulating film 3 during the film formation, and this layer is formed when the thin barrier layer 7 is formed. This is inconvenient because it interferes with the control of the thickness.

  Further, although the film formation at a low temperature hinders the progress of inadvertent oxidation of the Cu alloy film (for example, Cu · Mn alloy film) 5, the Cu film is caused by the difference in thermal expansion coefficient between the insulating film 3 and the Cu alloy film 5. The alloy film 5 comes off from the insulating film 3, which is not desirable. In order to avoid inadvertent oxidation of the Cu alloy film 5 and prevent peeling from the insulating film 3, the temperature is set to −50 ° C. or higher and + 100 ° C. or lower, more preferably −20 ° C. or higher and + 80 ° C. or lower. Is preferred.

  The deposition rate (film deposition rate, film growth rate) when depositing the Cu alloy film (for example, Cu · Mn alloy film) 5 on the insulating film 3 is 2 nanometers (unit: nm) or more per minute. It is preferable to set it to 300 nm or less per minute. The Cu alloy film 5 formed at a high speed exceeding 300 nm per minute becomes a film lacking in continuity because the internal structure becomes messy and a large amount of voids are generated. In the Cu alloy film 5 lacking in continuity including the cavities, the Mn diffusion does not occur uniformly, and the area where the insulating film 3 and the Cu alloy film 5 are in contact with each other is reduced due to the presence of the cavities. Inconveniences that do not lead to obtaining a Cu alloy film 5 having excellent adhesion to 3 are caused.

  On the other hand, the Cu alloy film 5 formed at a low speed of less than 2 nm per minute is a film having a dense internal structure, but diffuses Mn contained in the Cu alloy film 5 to the insulating film 3 side. Longer heat treatment is required at higher temperatures. For this reason, the thickness of the barrier layer 7 formed with the heat treatment is increased, which hinders the formation of the thin barrier layer 7 in the wiring groove 4 having a narrow opening width.

  Therefore, it is suitable that the Cu alloy film (for example, Cu · Mn alloy film) 5 is formed on the insulating film 3 at a rate of 2 nm / min or more and 300 nm / min or less. By depositing at a rate in this range, it is possible to obtain the Cu alloy film 5 containing almost no cavities at the junction with the insulating film 3 or inside the Cu alloy film 5. Therefore, the Cu alloy film 5 having excellent continuity, which is convenient for stably providing an atomic concentration distribution of Cu and Si described later, is obtained.

(Cu buried layer 6)
Cu is embedded in the opening 4 in which the Cu alloy film 5 is formed to form a Cu embedded layer 6. Cu can be embedded by, for example, forming means such as electroplating (plating), CVD method, high-frequency sputtering method or the like.

(Barrier layer 7)
After the Cu buried layer 6 is formed on the Cu alloy film 5, heat treatment is performed so that the Cu alloy film 5 is integrated with Cu of the Cu buried layer 6 to form the wiring body 8, and the Cu alloy film 5 and the insulating film 3 are also formed. Between these, the barrier layer 7 is formed. By this heat treatment, Cu, Mn which is an element forming an alloy with Cu, and Si which is an element constituting the insulating film 3 are thermally diffused, and a barrier layer 7 containing Cu, Mn and Si is formed.

  The temperature at which the heat treatment is performed is suitably 150 ° C. or more and 600 ° C. or less. In the heat treatment at a temperature lower than 150 ° C., diffusion of an element constituting the insulating film 3 such as Si from the insulating film 3 to the barrier layer 7 side does not sufficiently proceed, so that, for example, Si sufficiently adapts into the barrier layer 7. Therefore, the barrier layer 7 having poor adhesion to the insulating film 3 is disadvantageous. On the other hand, heat treatment at a high temperature exceeding 600 ° C. is disadvantageous because Si diffusion from the insulating film 3 side to the inside of the barrier layer 7 becomes remarkable, resulting in the barrier layer 7 having poor barrier properties.

The heat treatment is a pure inert gas (for example, an inert gas containing 0.2 vol. Ppm or less of oxygen) that inevitably contains oxygen (O ₂ ), or 75 vol. It is preferred to carry out in an air stream consisting of an inert gas containing ppm oxygen. Further, since nitrogen gas or hydrogen gas does not react with Cu, it can be used in the same manner as an inert gas, and nitrogen gas or hydrogen gas containing only oxygen (O ₂ ) inevitably (for example, 0.2 vol.ppm or less) Nitrogen gas or hydrogen gas containing oxygen), or 75 vol. You may make it implement in the airflow which consists of nitrogen gas or hydrogen gas containing ppm oxygen.

  When heat treatment is performed in a pure inert gas, nitrogen gas, or hydrogen gas atmosphere that inevitably contains oxygen only, the resistance of the wiring body 8 decreases as the heat treatment time elapses, as will be described in detail later. It was. This is because the alloy element contained in the Cu alloy film 5 diffuses to the interface with the insulating film 3 to form the barrier layer 7, and the alloy element not involved in the formation of the barrier layer 7 diffuses into the Cu buried layer 6. Then, by reacting with oxygen in an inert gas, nitrogen gas, or hydrogen gas atmosphere on the surface of the wiring body 8 to form an oxide, the alloy element concentration in the Cu alloy film is reduced, and the Cu buried layer 6 This is because a low-resistance wiring main body 8 is obtained which is pure Cu having the same composition as the above.

The volume ratio of oxygen molecules is 75 vol. Oxidation of the Cu alloy film 5 (for example, Cu • Mn alloy film) and the Cu buried layer 6 is disadvantageously promoted for the present invention by heat treatment in an inert gas, nitrogen gas, or hydrogen gas atmosphere containing more than ppm. Therefore, there is a disadvantage that the electrical resistance of the wiring body 8 is increased.
Examples of the inert gas include helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe). Among these, it is desirable that the inert gas is He, Ne, or Ar. Furthermore, considering the economical efficiency of the heating process, it is preferable to use Ar as the inert gas constituting the atmosphere. Further, when nitrogen gas or hydrogen gas is used instead of the inert gas, the heat treatment can be performed at a lower cost.

  In the above heat treatment, the Cu alloy film (for example, Cu · Mn alloy film) 5 reacts with oxygen contained in the insulating film 3 to form a barrier layer 7 at the interface. By the way, the thickness of the barrier layer 7 formed at a predetermined heat treatment temperature and time is determined. For this reason, if the initial Cu alloy film 5 contains a large amount of Mn, it is used for the formation of the barrier layer 7. Other than the broken Mn remains in the Cu alloy film 5 and increases the resistance of the wiring body 8. For this reason, it is necessary to reduce the wiring resistance by discharging the remaining Mn to the outside. As the method, an inert gas containing nitrogen as an inevitable impurity, nitrogen gas, hydrogen gas, or 75 vol. An oxide is formed on the surface of the wiring body 8 by reacting excess Mn with oxygen contained in the atmosphere using an inert gas, nitrogen gas, or hydrogen gas containing oxygen of ppm or less. As a result, Mn inside the wiring disappears from the inside of the wiring body 8 in the form of the barrier layer 7 and the surface oxide of the wiring body 8, and the wiring resistance becomes equivalent to pure Cu.

  That is, there is an insulating film 3 containing oxygen, a Cu alloy film 5 and a Cu buried layer 6. When heat treatment is performed in this state, Mn in the Cu alloy film 5 reacts with the insulating film 3 to form a barrier. If the layer 7 is formed but the oxygen atmosphere at this time is not adjusted, surplus Mn other than that used to form the barrier layer 7 remains in the wiring. In order to discharge this Mn to the outside, a trace amount of oxygen in an inert gas, nitrogen gas, or hydrogen gas atmosphere is required. If the amount of oxygen is appropriate, Mn oxide is formed on the surface of the wiring body 8, Mn is discharged from the wiring body 8 and Cu in the wiring body 8 is not oxidized. However, if the amount of oxygen is too large, not only the oxidation of Mn but also the Cu of the wiring body 8 is oxidized, resulting in an increase in wiring resistance.

  For the Cu alloy film (for example, Cu · Mn alloy film) 5 and the Cu buried layer 6 having almost no cavities formed on the insulating film 3 containing Si at the above-described preferable deposition rate, the above-mentioned preferable inert gas or nitrogen is used. By performing a heat treatment in a gas or hydrogen gas atmosphere at a temperature in the above range, Cu forming the Cu alloy film 5 is distributed in the barrier layer 7 so as to monotonously decrease toward the insulating film 3 side. be able to.

  The above-mentioned preferred inert gas is used for the Cu alloy film (for example, Cu · Mn alloy film) 5 and the Cu buried layer 6 having almost no cavities formed on the insulating film 3 containing Si at the preferred deposition rate. By applying heat treatment at a temperature in the above range in an atmosphere of nitrogen gas or hydrogen gas, Si constituting the insulating film 3 is placed inside the barrier layer 7 so as to monotonously decrease toward the Cu alloy film 5 side. Can be distributed.

  Still further, the above-mentioned preferred non-cavity for the Cu alloy film (for example, Cu · Mn alloy film) 5 and the Cu buried layer 6 having almost no cavities formed on the insulating film 3 containing Si at the above preferred deposition rate. By performing heat treatment at a temperature in the above range in an active gas, nitrogen gas, or hydrogen gas atmosphere, Mn atoms are introduced into regions in the barrier layer 7 where the concentrations of both Si and Cu atoms are substantially equal. It can be distributed so as to have the maximum atomic concentration inside the barrier layer 7 in a concentrated manner. In the present invention, the substantially equivalent atomic concentration means that the atomic concentration of Cu and Si is equal, or the atomic concentration of Si is within a range of ± 20% with respect to the atomic concentration of Cu.

The concentrated distribution of Mn atoms indicates a state where Mn is locally distributed as illustrated on the right side of FIG. The distribution of the atomic concentration of such an element can be investigated using, for example, electron energy loss spectroscopy (EELS) using a general field emission transmission electron microscope.
Mn is distributed so as to have the maximum atomic concentration inside the barrier layer 7 for the following reason. That is, since the oxide formation energy of Mn is lower than Cu and higher than Si, Mn reacts with oxygen in SiO ₂ and diffuses to the interface to form an oxide. At this time, in order to form a complex oxide containing Cu and Si as a feature of Mn, the wiring body 8 side in the vicinity of the interface (barrier layer 7) is a Mn oxide incorporating Cu, and one of the insulations On the layer 3 side, a Mn oxide incorporating Si is formed. These Mn oxides prevent Cu diffusion from the wiring body 8 side and Si diffusion from the insulating layer 3 side, so that the region where the Mn oxide takes in Cu and Si is limited. As a result, the concentration of Cu and Si decreases in the central portion of the interface layer (barrier layer 7), and Mn forms the maximum concentration.

  In addition, the Mn atoms are concentratedly distributed in the region inside the barrier layer 7 where the atomic concentrations of Cu and Si are substantially equal, because the concentration of Cu atoms and Si atoms is balanced. It is inferred that there is also a cause for the generation of a balanced electric field. In any case, the concentration distribution of Mn in such a specific region inside the barrier layer 7 is deposited at the above-mentioned preferable deposition rate, and there is almost no cavity, so that the diffusion of Mn atoms is uniform. This can be achieved by using the Cu alloy film 5 occurring in the above.

Mn atoms intensively distributed in a region inside the barrier layer 7 in which the atomic concentrations of Cu and Si are substantially equal are further diffused by Cu from the wiring body 8 side toward the insulating film 3 side, and the insulating film 3 has the effect of preventing the further diffusion of Si from 3 toward the wiring body 8 side. Shed information, and electrically insulating deterioration of the insulating film 3 due to entering the insulating film 3 inside the Cu diffused from the wiring main body 8, the diffusion of the Si wiring body 8 constituting the insulating film 3 Therefore, it is possible to effectively suppress the increase in resistance of the wiring body 8 at the same time.

  Next, the thickness of the barrier layer 7 will be described. Increasing the ratio of the thickness of the barrier layer 7 to the horizontal width (opening width) W of the wiring groove 4 is disadvantageous for forming the wiring body 8 having a low resistance. As the thickness of the barrier layer 7 formed in the wiring groove 4 having a certain opening width increases, the volume of the wiring body 8 decreases and the resistance of the wiring body 8 increases.

  For this reason, in the present invention, the barrier layer 7 containing Cu, Mn, and Si has a thickness of 1 nm or more and 1/5 or less of the opening width W of the wiring groove 4 provided in the insulating film 3 (see FIG. 1). At the same time, the thickness of the barrier layer 7 is at most 10 nm. If the barrier layer 7 is an ultrathin film having a thickness of less than 1 nm, it cannot be a barrier layer that can function sufficiently to prevent diffusion of Cu and Si in the first place, which causes a problem. On the other hand, when the layer thickness exceeds 1/5 of the opening width W of the wiring groove 4 or when the layer thickness exceeds 10 nm even when it does not exceed 1/5 (for example, the barrier layer when the opening width W is 90 nm) 7 is 15 nm (1/6)), and the barrier layer 7 is too thick to form a wide (large volume) wiring body 8. Further, it is difficult to form the wiring body 8 made of Cu having a resistivity of about 2 μΩ · cm, which is as small as that of pure Cu.

  The thickness of the barrier layer 7 according to the present invention is preferably reduced as the opening width W of the wiring groove 4 is reduced in order to provide a low-resistance wiring body 8. For example, the barrier layer 7 having a thickness of 5 nm to 10 nm is formed inside the wiring groove 4 having an opening width W of 90 nm ± 5 nm. Further, a barrier layer 7 having a thickness of 7 nm ± 3 nm is formed inside the wiring groove 4 having an opening width W of 65 nm ± 3 nm. Further, a barrier layer 7 having a thickness of 5 nm ± 2 nm is formed inside the wiring groove 4 having an opening width W of 45 nm ± 2 nm. Further, a barrier layer 7 having a thickness of 3.5 nm ± 1 nm is formed in the wiring groove having an opening width W of 32 nm ± 2 nm.

For example, in the formation of a damascene structure wiring having the barrier layer 7 according to the present invention, the barrier includes Cu, Mn, and Si having a thickness corresponding to the opening width W of the wiring groove 4 of the wiring. In forming the layer 7 by heat treatment of the Cu · Mn alloy film 5, the layer thickness of the barrier layer 7 includes the logarithm of the heat treatment time (t : t> 0) as shown in the following formula (1). It is formed with a heat treatment time given by

Here, x is the desired thickness of the barrier layer 7 (unit: nm), k is a proportional constant related to the heat treatment time, t is the heat treatment time (unit: hour), and C is a constant (unit: nm) related to the heat treatment temperature (unit: ° C.).
For example, oxygen (O ₂ ) in a volume concentration of 50 vol. Taking as an example a case where heat treatment is performed at 450 ° C. in an argon (Ar) atmosphere containing ppm, the relationship between x (nm) and t (hour) (t> 0) is given by the following equation (2). . However, when t = 0, x = 0.

  Further, taking as an example the case of heat treatment at 350 ° C. in the same atmosphere as described above, the relationship between x (nm) and t (hour) (t> 0) can be expressed by the following equation (3). However, when t = 0, x = 0.

The proportionality constant k and the constant C shown in the above formula (1) are both as shown in the formula (2) and the formula (3) as the heat treatment temperature is lowered when the heat treatment is performed in the same atmosphere. Small value. It is desirable that the heat treatment temperature be lower as the barrier layer 7 having a smaller thickness is formed at any heat treatment temperature. When heat treatment is performed at a constant temperature, it is desirable to increase the heat treatment time in order to obtain a thicker barrier layer 7.
For example, in order to obtain the barrier layer 7 having a layer thickness of 5 nm by heat treatment at 450 ° C., the same temperature is maintained for 1 hour. Further, for example, in order to obtain a barrier layer 7 having a layer thickness of 3 nm by heat treatment at 350 ° C., the same temperature is maintained for 1 hour. For example, in order to obtain the barrier layer 7 having a thickness of 2 nm by heat treatment at 250 ° C., the temperature is maintained for 3 hours.

  The heat treatment time referred to in the present invention is the time from when the temperature reaches the temperature for heat treatment to when cooling is started. It is desirable that the heat treatment time is 60 minutes or more over the entire range of the above desirable heat treatment temperature. Even in the heat treatment for a long time of 100 hours or 200 hours, the thickness of the formed barrier layer 7 increases in proportion to the logarithmic value of the heat treatment time described above. The maximum time is preferably 10 hours.

Next, the amorphous barrier layer 7 will be described. The barrier layer 7 is made of an amorphous material having no crystal grain boundary, which is a preferential path through which the constituent atoms of the insulating film 3 and the wiring body 8 disposed on both sides of the barrier layer 7 can easily diffuse to each other. Preferred above.
As described above, the heat treatment temperature at the time of forming the barrier layer is suitably 150 ° C. or higher and 600 ° C. or lower. However, when the barrier layer 7 is made amorphous, it is 150 ° C. or higher and 450 ° C. or lower. preferable.

  In the heat treatment at a temperature lower than 150 ° C., as described above, since Si of the insulating film 3 is not mixed so as to be sufficiently adapted to the barrier layer 7, it becomes difficult to ensure adhesion with the insulating film 3, and Cu Mn or the like of the alloy film 5 cannot be sufficiently thermally diffused toward the insulating film 3, and therefore, a barrier layer having a sufficient barrier function cannot be stably formed.

  Further, when heat treatment is performed at a high temperature exceeding 450 ° C., thermal diffusion of elements such as Mn in the Cu alloy film 5 toward the insulating film 3 can be promoted, but a polycrystalline barrier containing a large amount of crystal grain boundaries. Layer 7 will result. As a result, atomic diffusion occurs through the crystal grain boundary and the barrier property against diffusion is lost, and the element operating current leaks inside the insulating film that should isolate the wiring by the element diffused and mixed in the insulating layer. It is also inconvenient.

  When the heat treatment temperature is in the range of 150 ° C. or higher and 450 ° C. or lower, Mn of the Cu alloy film 5 moves to the interface between the Cu alloy film 5 and the insulating film 3 and an amorphous barrier layer 7 is formed. At this time, as described above, ionized Mn is present on the side of the wiring body 8 in contact with the barrier layer 7, and an electric field is formed on both sides of the barrier layer 7 that is being formed. This electric field accelerates the diffusion of Mn ions in the barrier layer 7 so that the growth rate of the barrier layer 7 is proportional to the logarithm of time. As a result, the thickness rapidly increases at the initial stage of formation of the barrier layer 7, and the rate of change in thickness becomes slower as time elapses. Therefore, the amorphous barrier layer 7 can be stably formed even in heat treatment at a relatively low temperature of 150 ° C., and the barrier layer 7 having excellent diffusion barrier properties and electrical barrier properties can be obtained by the amorphous properties. Can do. Even if heat treatment is performed at 450 ° C. for 100 hours for a long time, the amorphous barrier layer 7 can be stably formed, and the diffusion barrier property and the electrical barrier property can be maintained.

  When the barrier layer 7 is formed in this way, divalent or trivalent ionized Mn exists on the side of the wiring body 8 in contact with the barrier layer 7. Accordingly, positive charges exist on the side of the wiring body 8 adjacent to the barrier layer 7, and an electric field is formed between the side of the insulating film 3 facing the barrier layer 7 and formed on both sides of the barrier layer 7. Since the wiring body 8 and the insulating film 3 are attracted to the barrier layer 7 by the applied electric field, the effect of improving the adhesion at the interface can also be obtained from this point.

  The deposition is performed at a relatively high rate within the preferred deposition rate range disclosed by the present invention (2 nm / min to 300 nm / min), and then the preferred temperature range disclosed by the present invention (150 ° C. to 450 ° C.). If the heat treatment is performed at a relatively low temperature, the barrier layer 7 made of amorphous can be formed. In addition, in the region inside the amorphous barrier layer 7 where the Cu atoms diffused from the Cu alloy film 5 and the concentration of Si atoms contained in the insulating film 3 are substantially equal, the atomic concentration of Cu or Si is increased. On the other hand, the barrier layer 7 in which Mn atoms are concentrated at a concentration twice or more can be formed.

  The amorphous barrier layer 7 having the above-described atomic concentration relationship between Cu, Si, and Mn is formed by depositing a Cu alloy film 5 on the insulating film 3 at a rate of 7 nm / min or more and 300 nm / min or less. After depositing at a rate and forming a Cu buried layer 6 on the Cu · Mn alloy film 5, the Cu · Mn alloy film 5 and the Cu buried layer 6 are inevitably pure oxygen or nitrogen containing oxygen. In an atmosphere consisting of gas, hydrogen gas, or oxygen up to 75 vol. It can be stably obtained by heating at a temperature of 150 ° C. or higher and 450 ° C. or lower in an atmosphere composed of inert gas, nitrogen gas, and hydrogen gas contained at a ratio of ppm.

  If Mn is concentrated in the region inside the amorphous barrier layer 7 in which the concentrations of Cu atoms and Si atoms are substantially equal to each other so as to exceed these concentrations, Mn is the main component. The diffusion of Cu and Si can be more effectively suppressed by the action of preventing the diffusion of the oxide to Cu and Si. Further, by concentrating and distributing Mn atoms having a concentration twice or more the concentration of Cu atoms or Si atoms in the same region, it is possible to further sufficiently prevent Cu and Si from diffusing.

  In the heat treatment performed at a high speed as described above and at a relatively low temperature, an amorphous barrier layer having no grain boundary is stably formed. For this reason, Cu and Si through the grain boundary are formed. Abnormal diffusion will be suppressed. Whether or not the barrier layer 7 is amorphous can be known from, for example, an electron diffraction image.

  In the above description, the heat treatment is performed after the Cu buried layer 6 is formed on the Cu alloy film 5, but may be performed after the Cu alloy film 5 is formed. Further, after the Cu buried layer 6 is buried in the wiring groove 4, the surface of the Cu buried layer 6 may be polished and planarized by, for example, CMP (Chemical Mechanical Polishing), and then heat treatment may be performed.

  In the above description, the barrier layer 7 is formed on the basis of the Cu alloy film 5 formed by a method such as sputtering of the target material. However, the barrier layer 7 having the configuration according to the present invention is formed of Si. First, a Mn film may be deposited on the insulating film 3 containing, and then a multilayer film having a structure in which a Cu film is deposited on the Mn film may be formed. Alternatively, a Cu film may be first deposited on the insulating film 3 containing Si, and then formed based on a multilayer film having a structure in which a Mn film is deposited on the Cu film. Then, a Cu buried layer 6 is formed on the multilayer film and subjected to heat treatment to form a barrier layer 7, and before the Cu buried layer 6 is formed, the multilayer film is subjected to heat treatment to form a barrier layer. The Regardless of the order of layering, if the deposition rate of the Cu film and the Mn film is within the above-mentioned preferable range as in the case of the Cu alloy film 5, an Mn film and a Cu film with few cavities can be obtained. is there.

(Wiring body 8)
A Cu alloy film 5 containing almost no cavities deposited at a speed suitable for the present invention is formed, and further Cu is in contact with the Cu alloy film 5 by a general high-frequency sputtering method so that Cu is formed inside the wiring groove 4. By embedding the Cu buried layer 6 and then performing the above heat treatment, the wiring resistance of the wiring body 8 becomes substantially equal to that of pure Cu, and the low resistance wiring body 8 can be obtained.

  As described above, in the first embodiment of the present invention, the barrier layer 7 made of an oxide containing Cu, Si, and Mn is formed between the wiring body 8 and the insulating film 3, and the barrier layer is formed. 7, the atomic concentration of Cu monotonously decreases from the wiring body 8 side toward the insulating film 3 side, and the atomic concentration of Si decreases monotonously from the insulating film 3 toward the wiring body 8 side. Since the atomic concentration of Mn is maximized in a region where the atomic concentration is substantially equal, the barrier layer 7 is a thermally stable and structurally dense oxide layer. Therefore, the barrier layer 7 has an effective configuration for suppressing diffusion, has a good barrier property against Cu diffusion from the wiring body 8 side, and has a better insulating property of the insulating film 3. Can be. Further, it has a good barrier property against the diffusion of Si from the insulating film 3 side, and the wiring body 8 can have a lower resistance. Accordingly, a low-power-consumption semiconductor device can be provided with wiring that can prevent leakage of element operating current with low resistance.

  Further, since the atomic concentration of Cu in the barrier layer 7 is monotonously decreased from the side of the wiring body 8 containing Cu as the main component toward the insulating film 3 side, the barrier layer 7 and Cu are used as the main components. Since the atomic concentration distribution is not isolated from the wiring main body 8 and the Cu concentration changes continuously, the adhesion with the Cu film forming the wiring main body 8 can be further improved. It is possible to make the device excellent in operation reliability over a long period of time.

  Further, the barrier layer 7 becomes an oxide mainly containing Si and Mn due to diffusion reaction at the interface with the insulating film 3, and the atomic concentration of Si in the barrier layer 7 is changed from the insulating film 3 to the wiring body 8 side. It is decreasing monotonously toward. Therefore, the Si composition distribution from the insulating film 3 is not a steep discontinuous distribution at the interface with the barrier layer 7, but a continuous distribution. For this reason, the interface strength between the insulating film 3 and the barrier layer 7 is increased, and the adhesion with the insulating film 3 can be improved. From this point, the semiconductor device is excellent in operation reliability over a long period of time. can do.

  As described above, in the present invention, it is possible to reduce the power consumption of the semiconductor device by reducing the resistance of the wiring body 8 and improving the insulating property of the insulating film 3, and between the barrier layer 7 and the wiring body 8. By improving the adhesion and improving the adhesion between the barrier layer 7 and the insulating film 3, it is possible to make the semiconductor device excellent in operation reliability over a long period of time.

  In addition, since the atomic concentration of Mn in the region of the barrier layer 7 where the atomic concentrations of Cu and Si are substantially equal to each other is more than twice the atomic concentration of Cu or Si, Cu or Si is mainly used. If an oxide is used, the oxide continues to grow continuously. However, since the oxide is mainly composed of Mn, the growth of the barrier layer 7 follows the logarithm rule of time. The reason why the logarithmic rule is followed is considered to be due to the following reason. That is, the oxide mainly composed of Mn of the barrier layer 7 has a dense structure and slow diffusion, so that the growth of the oxide does not occur by normal thermal diffusion, and free electrons associated with Mn atoms are generated by the barrier layer 7. And the ionized Mn exists on the side of the wiring body 8 in contact with the barrier layer 7, and an electric field is formed on both sides of the barrier layer 7 that is being formed. This electric field accelerates the diffusion of Mn ions in the barrier layer 7, thereby causing growth of oxides mainly composed of Mn. With such growth behavior, the growth rate of the barrier layer 7 follows the logarithm rule of time. As a result, the thickness of the barrier layer 7 is rapidly increased in the initial stage, and when the time elapses, the rate of change of the thickness is reduced, and the barrier layer 7 is suppressed from growing to several nm or more. For this reason, the barrier layer 7 is a thermally stable and structurally dense coating made of Mn oxide, which is more effective for suppressing diffusion. Therefore, the barrier action of the barrier layer 7 against the diffusion of Cu from the wiring body 8 side and the diffusion of Si from the insulating film 3 side is further improved, and the insulating properties of the insulating film 3 and the low resistance of the wiring are further improved. Can be made.

In addition, since the barrier layer 7 has a thickness of 1 nm or more and is 1/5 or less of the groove width of the opening so as to ensure the thickness of the barrier layer 7, Cu diffusion from the wiring body 8 side or insulation The barrier action of the barrier layer 7 against the diffusion of Si from the film 3 side is ensured. At the same time, since the thickness of the barrier layer 7 is set to 10 nm or less at the maximum, the wiring body 8 is narrowed by the barrier layer 7, and it is possible to reliably prevent adverse effects such as an increase in the effective electrical resistance of the wiring. . Therefore, the insulation of the insulating film 3 and the low resistance of the wiring can be obtained more reliably.
In addition, since the barrier layer 7 is amorphous, it is possible to suppress abnormal diffusion of Cu and Si through the grain boundary. Therefore, the barrier action of the barrier layer 7 is improved, and the insulating property of the insulating film 3 and the low resistance of the wiring can be reliably maintained.

  In addition, according to the present invention, since Mn ionized bivalently or trivalently exists on the side of the wiring body 8 in contact with the barrier layer 7, a positive charge exists on the side of the wiring body 8 adjacent to the barrier layer 7. Then, an electric field is formed between the insulating layer 3 and the barrier layer 7 facing each other. Since the wiring body 8 and the insulating film 3 are attracted to the barrier layer 7 by the electric field formed on both sides of the barrier layer 7, the effect of improving the adhesion at the interface can be obtained, and the semiconductor device can be used for a long time. The operation reliability can be improved.

  Further, according to the present invention, in the heat treatment step, the heat treatment is inevitably performed with pure inert gas, nitrogen gas, hydrogen gas, or oxygen containing oxygen at a maximum of 75 vol. Since it is performed in an inert gas, nitrogen gas, or hydrogen gas contained at a ratio of ppm, alloy elements such as Mn that diffuse and move to the surface of the wiring body 8 without being involved in the formation of the barrier layer 7 are inert. Oxidized with a small amount of oxygen contained in gas, nitrogen gas, or hydrogen gas to form an oxide on the surface of the wiring body 8 and disappear from the inside of the wiring body 8 in the form of a surface oxide of the wiring body 8. . Accordingly, the wiring resistance is substantially equal to that of pure Cu, and a low-resistance wiring body 8 can be obtained.

  In the present invention, since the heat treatment in the heat treatment step is performed at a temperature of 150 ° C. or more and 600 ° C. or less, the barrier layer 7 can have a specific configuration according to the present invention, and the resistance of the wiring body 8 can be reduced. In addition, various effects such as improvement of the insulating property of the insulating film 3 and improvement of adhesion to the wiring body 8 and the insulating film 3 can be brought about.

  In the present invention, since the heat treatment in the heat treatment step is performed at a temperature of 150 ° C. or higher and 450 ° C. or lower, the amorphization of the barrier layer 7 can be formed more stably.

According to the present invention, it can be effectively used as a wiring for constituting various semiconductor devices that require a wiring including a low-resistance wiring body 8 and an insulating film 3 having excellent insulating properties.
For example, if the barrier layer 7 having a distribution of atomic concentrations of Cu, Mn, and Si according to the present invention is used, it is not necessary to form a thick barrier layer from a Ta-based material as in the prior art, and as a barrier layer even if it is thin. Since it can function satisfactorily, it can be used to construct a wiring for a silicon LSI having a small wiring width, for example, a wiring width of 90 nm or less in order to integrate at a high density.

  In addition, for example, the wiring according to the present invention includes a low-resistance wiring body 8 and a barrier layer 7 that can prevent diffusion of Cu and Si so as to be convenient for preventing leakage of element operating current. Therefore, it can be used to construct a wiring for a power device made of silicon or silicon germanium (SiGe) mixed crystal that requires a large element operating current to flow.

  In addition, since the wiring structure according to the present invention includes the barrier layer 7 that can avoid leakage of the element operating current, it can be suitably used to configure an electronic device with low power consumption. For example, it can be used to construct wiring for display electronic devices such as flat display devices (FDP), organic electroluminescence (EL) devices, inorganic EL devices, or photovoltaic elements such as solar cells. it can.

  Before describing the first embodiment of the present invention more specifically, first, as a first example, a simple structure in which a flat Cu · Mn alloy film is formed on a flat insulating film will be described. . The reason why the flat and simple structure is adopted is to measure the electrical resistivity of the formed Cu layer with higher accuracy.

Example 1
FIG. 2 is a cross-sectional view showing a laminated state before heat treatment in Example 1, and FIG. 3 is a cross-sectional view showing a laminated state after heat treatment in Example 1.
In FIG. 2, a Cu · Mn alloy film 105m is formed on an insulating film 103m made of SiO ₂ , and heat treatment is performed in this laminated state, whereby Mn atoms contained in the Cu · Mn alloy film 105m are converted into an insulating film. Thermal diffusion was performed toward the interface with 103m, and as shown in FIG. 3, a barrier layer 107m was formed in a region near the interface. In addition, by this heat treatment, Mn diffuses and escapes to the surface layer side of the Cu · Mn alloy film 105m, and the Cu · Mn alloy film 105m becomes a Cu layer 108m in which Cu is substantially occupied, and the surface layer of the Cu layer 108m has Mn An oxide film 109m was formed. The Cu layer 108m corresponds to the wiring main body 8 in the first embodiment, and is formed from substantially pure Cu. Here, the Cu · Mn alloy film 105m was formed to a thickness of 150 nm with a Cu atomic concentration ratio of 96% and a Mn atomic concentration ratio of 4%. By subsequent heat treatment, the thickness of the barrier layer 107m was 3 nm, and the thickness of the Mn oxide film 109m was 14 nm.

In the heat treatment, an inert gas, argon (Ar) gas, was used as the atmospheric gas. FIG. 4 shows the resistivity (specific resistance) of the Cu layer 108m formed by heat treatment at 350 ° C. while changing the volume content of oxygen in the argon gas.
In FIG. 4, the horizontal axis represents heat treatment time (unit: seconds), and the vertical axis represents resistivity (unit: μΩcm). Each curve shows the resistivity of the Cu layer 108m formed by heat treatment under various gas atmosphere conditions A to D. Among the gas atmosphere conditions A to D, A is an argon gas atmosphere having a volume content of oxygen of 50 ppm, B is a high purity argon gas atmosphere, C is an argon gas atmosphere having a volume content of oxygen of 1000 ppm, and D is a vacuum (here Then, 5 × 10 ⁻⁷ Torr). As shown in Table 1, the high purity argon gas atmosphere of B inevitably contains oxygen in a volume content of 0 to 0.2 ppm. Here, among product standards G1, G2, and G3, G2 is included. used.

  From FIG. 4, the volume concentration is 50 vol. When heat treatment is performed in an argon gas atmosphere (gas atmosphere condition A) containing ppm oxygen, the barrier layer 107m having the atomic concentration distribution of Cu, Mn, and Si according to the present invention can be formed, and the resistance of the Cu layer 108m The rate decreases rapidly in a few minutes, becomes a small value of about 2.0 to 2.2 μΩ · cm in about 30 minutes, and is at a level almost equivalent to that of pure Cu (a thin film made of pure Cu). The electrical resistivity is 1.9 to 2.0 μΩ · cm).

  Further, if the heat treatment is performed in a high purity argon gas atmosphere (gas atmosphere condition B), the resistivity of the Cu layer 108m decreases slightly more slowly than in the gas atmosphere condition A, but about 30 minutes. 2.0 μΩ · cm, and after crossing with the gas atmosphere condition A, it continuously decreases with time, and decreases to about 1.9 μΩ · cm in about 90 minutes. The level is equivalent.

  Under the gas atmosphere condition A, the resistivity of the Cu layer 108m was significantly reduced because Mn present in the Cu · Mn alloy film 105m diffused to the surface of the Cu layer 108m to form a Mn oxide film 109m. This is probably because the Cu layer 108m was discharged. Further, in the gas atmosphere condition B, the resistivity of the Cu layer 108m was significantly reduced because the oxygen concentration in the atmosphere was extremely low and the oxygen amount in the condition A was discharged while discharging Mn of the Cu layer 108m. This is probably because the oxidation inside the Cu layer 108m generated due to the large amount could be further suppressed.

  On the other hand, in an argon gas atmosphere (gas atmosphere condition C) with an oxygen volume content of 1000 ppm, the resistivity of the Cu layer 108m decreases in the initial stage, but increases after that because the surface oxidation is intense. Further, in the vacuum (gas atmosphere condition D), the resistivity of the Cu layer 108m is reduced in the initial stage as in the case of the condition C, but does not decrease thereafter and becomes substantially constant or in vacuum. It is rising moderately due to the slow surface oxidation.

  As described above, when the heat treatment according to the present invention is applied to the Cu · Mn alloy film 105m, the Cu layer 108m formed from the Cu · Mn alloy film 105m comes to be formed from pure Cu and its electrical resistivity. Was found to be substantially equivalent to pure Cu.

  Next, more specific contents of the first embodiment of the present invention will be described. That is, a wiring groove 4 is formed on an insulating film 3 containing Si, and a low-resistance wiring body 8 made of Cu is formed on the basis of the Cu · Mn alloy film 5 formed in the wiring groove 4, and Cu and Mn An example of forming a wiring structure including a barrier layer 7 containing Si and Si will be described in detail.

(Example 2)
FIG. 5 schematically shows a cross-sectional structure inside the wiring groove in a state where a Cu · Mn alloy film is deposited on the insulating film and then a Cu buried layer is deposited. FIG. 6 schematically shows a cross-sectional structure inside the wiring groove after the heat treatment is applied to the Cu · Mn alloy film and the Cu buried layer in the wiring groove. FIG. 7 is a transmission electron microscope image showing the cross-sectional structure of the barrier layer formed by the heat treatment.

As schematically shown in FIG. 5, an SiO ₂ layer having a thickness of 150 nm is deposited as an insulating film 103 on the surface of the conductive silicon semiconductor layer 102 formed on the silicon substrate 101 by a general chemical vapor deposition method. did. Next, a part of the insulating film 103 was removed by etching using a general photolithography technique to form a wiring groove (opening) 104. The opening width (lateral width) W of the wiring groove 104 was 90 nm.

  Next, a Cu / Mn alloy film 105 was deposited on the surface of the insulating film 103 and the side surface and the bottom surface of the wiring groove 104. The Cu · Mn alloy film 105 was formed by a general high-frequency sputtering method using a target material made of a Cu · Mn alloy containing 7% of Mn in atomic concentration. The Cu · Mn alloy film 105 was formed at a temperature of the silicon substrate 101 of 50 ° C. The deposition rate of the Cu / Mn alloy film 105 on the surface of the insulating film 103 was 12 nm per minute. It was quantified by the EELS method that the atomic concentration ratio of Mn in the Cu · Mn alloy film 105 was 5%. The layer thickness of the Cu · Mn alloy film 105 was set to 80 nm on the flat surface 103a of the insulating film 103 where the wiring groove 104 was not formed. At this time, a Cu · Mn alloy film of about 20 nm was formed on the groove bottom of the wiring groove 104.

  Next, Cu was plated on the surface of the Cu · Mn alloy film 105 by a general electrolytic plating method (not shown in FIG. 5). Cu was plated to such a thickness that the inside of the wiring groove 104 could be embedded. Next, the plated Cu layer and the Cu · Mn alloy film 105 were polished and removed by using a general CMP means until the flat surface 103a of the insulating film 103 was exposed. As a result, the Cu · Mn alloy film 105 was left only in the wiring groove 104, and Cu plated on the surface was left as the Cu buried layer 106.

  Next, the volume ratio of oxygen is 50 vol. 50 in the Cu · Mn alloy film 105 and the Cu buried layer 106 remaining in the wiring groove 104. Heat treatment was performed at a temperature of 300 ° C. for 30 minutes in an argon (Ar) atmosphere containing ppm. Thus, Mn atoms contained in the alloy film 105 were thermally diffused from the Cu / Mn alloy film 105 toward the interface with the insulating film 103. Thereby, the barrier layer 107 was formed in a region near the interface. The formed barrier layer 107 had a thickness of 5 nm. Further, by this heat treatment, Mn diffuses and escapes, and the surface layer portion of the Cu · Mn alloy film 105 in which Cu occupies almost the entire amount and the Cu buried layer 106 are integrated to form a wiring body 108 made of Cu. It was done. A transmission electron microscope image of the barrier layer 107 formed by this heat treatment is shown in FIG.

The concentration distribution of Cu, Mn, and Si atoms inside the barrier layer 107 was analyzed by electron energy loss spectroscopy (EELS). This EELS analysis was performed by scanning an electron beam at an interval of 0.2 nm using a high-resolution field emission transmission electron microscope (TEM). According to the analysis result, it was shown that the concentration of Cu atoms monotonously decreased from the wiring body 108 toward the SiO ₂ insulating film 103 side. It was also shown that the concentration of Si atoms monotonously decreased from the SiO ₂ insulating film 103 toward the wiring body 108 side.

  Further, according to TEM observation, almost no voids were found inside the barrier layer 107. For this reason, due to the uniform diffusion of Mn atoms, Mn atoms are concentrated in a region where the concentrations of Cu atoms and Si atoms substantially coincide. Further, the concentration of the accumulated Mn atoms was the highest in the region where the Cu atoms and the Si atoms in the barrier layer 107 had substantially the same concentration.

  Further, due to the heat treatment, Mn diffuses and escapes, and the surface layer portion of the Cu · Mn alloy film 105 in which Cu occupies substantially the entire amount and the Cu embedded layer 106 are integrated, and the wiring body 108 made of Cu. In addition, a Mn oxide film was also formed on the upper surface layer portion of the wiring body 108 (not shown in FIG. 6), but the upper surface layer oxide film was removed by CMP means. . As a result, the surface of the Cu wiring body 108 was exposed, and the electrical resistivity of the Cu wiring body 108 was measured. The electrical resistivity of the Cu wiring body 108 was extremely low, and became 2.5 μΩ · cm, which was substantially equivalent to a wiring formed by embedding pure Cu in a wiring groove having an opening width of 90 nm.

  As described above, according to Example 2 of the present invention, the low resistance Cu wiring close to the wiring made of pure Cu could be provided by the barrier layer 107 effective for suppressing diffusion. In addition, the insulating property of the insulating film 103 can be improved by the barrier layer 107, and thus the wiring can be prevented from leaking element operating current with low resistance, and a semiconductor device with low power consumption can be obtained. Further, the reliability of the operation of the semiconductor device over a long period of time is improved by improving the adhesion between the barrier layer 107 and the wiring body 108 and improving the adhesion between the barrier layer 107 and the insulating film 103. I was able to.

(Example 3)
The contents of the present invention will be specifically described by taking as an example the case where a wiring structure is formed using a barrier layer containing amorphous Cu, Mn and Si.

Cu (atomic concentration ratio = 93%) · Mn (atom) on the surface of the insulating film formed as described in Example 2 above, and on the side surface and the bottom surface of the wiring groove having an opening width of 90 nm (Concentration ratio = 7%) System alloy film was deposited by a general high-frequency sputtering method. In order to reliably form the amorphous barrier layer, the deposition rate of the Cu · Mn alloy film on the SiO ₂ insulating film was set to 10 nm per minute.

Next, as described in Example 2 above, Cu was deposited on the Cu · Mn alloy film by a general plating method. Thereafter, as described in Example 2 above, the Cu / Mn alloy film and the Cu plating are performed by general CMP means so that the Cu / Mn alloy film and the Cu buried layer remain only in the wiring groove. The layer was removed by polishing.
Thereafter, the Cu · Mn alloy film was heat-treated at 200 ° C. in order to form an amorphous barrier layer having no grain boundary that can cause normal diffusion of Mn. The atmosphere used for the heat treatment was the same as in Example 2 above except that 50 vol. Argon (Ar) atmosphere containing ppm was used. The heat treatment time was 4 hours. Thereby, a barrier layer having a layer thickness of 3 nm was formed.

  The electron diffraction image obtained using a general TEM was halo, and the obtained barrier layer was shown to be amorphous.

FIG. 8 shows the result of analysis by electron energy loss spectroscopy (EELS) on the distribution of elements inside the amorphous barrier layer. In elemental analysis by the EELS method, as shown in FIG. 8, the atomic concentration of Cu in the barrier layer decreases monotonously from the wiring body (Cu / Mn alloy film) side to the SiO ₂ insulating film side. It was confirmed that The atomic concentration of Si monotonously decreased from the SiO ₂ insulating film side toward the wiring main body (Cu · Mn alloy film) side as in the case of Cu atoms.

Further, similarly to the barrier layer described in Example 2 above, Mn atoms were concentrated in a region where the concentrations of Cu atoms and Si atoms substantially matched. In particular, as shown in FIG. 8, the concentration of Mn atoms accumulated in the region is significantly doubled at a location in the barrier layer where both the atomic concentrations of Cu and Si are 15 atomic%. It became 33 atomic% exceeding.
Further, the electrical resistivity of the Cu wiring body formed on the basis of the Cu buried layer is extremely low, and 2.4 μΩ · cm, which is substantially equivalent to a wiring formed by embedding pure Cu in a wiring groove having an opening width of 90 nm. became.

  As described above, according to the third embodiment of the present invention, as in the second embodiment, the amorphous barrier layer that is more effective for suppressing diffusion has a low resistance close to that of wiring made of pure Cu. Cu wiring can be obtained. In addition, the insulating property of the insulating film can be improved by the barrier layer. Therefore, the wiring has a low resistance and can prevent the leakage of the element operating current, and a semiconductor device with low power consumption can be obtained. In addition, the reliability of the operation of the semiconductor device over a long period of time can be improved by improving the adhesion between the barrier layer and the wiring body and improving the adhesion between the barrier layer and the insulating film.

Example 4
The present invention will be described in detail by taking as an example a case where a wiring structure is formed from a multilayer film of a Mn film and a Cu film formed on an insulating film containing Si.

First, a SiO ₂ layer (layer thickness = 100 nm) is deposited on a conductive silicon semiconductor layer formed on a silicon substrate, and then a SiOF layer (layer thickness = 80 nm) is deposited on the layer to form a multilayer structure. An insulating film was formed.

  Next, a wiring groove having an opening width of 45 nm as described in Example 2 was formed using a general photolithography technique. Thereafter, on the surface of the multilayer insulating film and the side surface and the bottom surface of the wiring groove having an opening width of 45 nm, first, using a target material made of high-purity (99.999%) Mn, A Mn film (film thickness = 8 nm) was deposited by a general high-frequency sputtering method. The deposition rate of this Mn film was 10 nm per minute.

Next, a Cu film (film thickness = 9 nm) was provided in contact with the Mn film by a general high-frequency sputtering method, and was stacked at a deposition rate of 10 nm per minute. Further, Cu was plated by a general electrolytic plating method on the Cu film forming the multilayer film as described in Example 2 above. Thereafter, as described in Example 2 above, the Cu film, Mn is formed by a general CMP means so that the multilayer film composed of the Cu film and the Mn film and the Cu buried layer remain only in the wiring groove. The film and Cu plating layer were removed by polishing.
Thereafter, the multilayer film composed of the Cu film and the Mn film and the Cu buried layer were heat-treated at 350 ° C. The atmosphere used for the heat treatment was 60 vol. Argon (Ar) atmosphere containing ppm was used. The heat treatment time was 4 hours. Thus, a barrier layer having a layer thickness of 3 nm was formed.

According to the distribution analysis of elements inside the barrier layer containing Cu, Mn and Si by the EELS method, the atomic concentration of Cu decreases monotonously from the Cu / Mn alloy film toward the SiO ₂ / SiOF multilayer insulating film side. It was confirmed that On the other hand, it was observed that the Si atomic concentration decreased monotonously from the SiO ₂ / SiOF multilayer insulating film toward the Cu / Mn alloy film side, as in the case of Cu atoms.

Similarly to the barrier layer described in Example 2 above, the region in which the concentrations of Cu atoms and Si atoms are approximately the same and is slightly closer to the SiO ₂ · SiOF multilayer insulating film than the center in the layer thickness direction of the barrier layer In this case, Mn atoms were accumulated intensively.
Also, the electrical resistivity of the Cu wiring body formed on the basis of the Cu buried layer is extremely low, and 3.4 μΩ · cm, which is substantially equivalent to a wiring formed by embedding pure Cu in a wiring groove having an opening width of 45 nm. became.

As described above, according to the fourth embodiment of the present invention, as in the second embodiment, the barrier layer effective for suppressing diffusion provides a low resistance Cu wiring close to a wiring made of pure Cu. I was able to. In addition, the insulating property of the insulating film can be improved by the barrier layer. Therefore, the wiring has a low resistance and can prevent the leakage of the element operating current, and a semiconductor device with low power consumption can be obtained. In addition, the reliability of the operation of the semiconductor device over a long period of time can be improved by improving the adhesion between the barrier layer and the wiring body and improving the adhesion between the barrier layer and the insulating film.
In Example 4, the heat treatment was performed at 60 vol. In an argon (Ar) atmosphere containing ppm, it was carried out at 350 ° C. for 4 hours, but this was performed at 60 vol. In a nitrogen gas atmosphere containing ppm and oxygen in a volume ratio of 60 vol. The same results as in Example 4 were obtained when each was conducted at 350 ° C. for 4 hours in a hydrogen gas atmosphere containing ppm.

(Example 5)
In this Example 5, the wiring structure provided with the barrier layer was formed by changing only the heat treatment condition from the above Example 2.

  The heat treatment was performed at a temperature of 300 ° C. for 90 minutes in a pure argon gas atmosphere inevitably containing only 0.1 ppm of oxygen in the Cu · Mn alloy film and the Cu buried layer. Thus, Mn atoms contained in the alloy film were thermally diffused from the Cu / Mn alloy film toward the interface with the insulating film 103, and a barrier layer was formed in a region near the interface. The thickness of the formed barrier layer was 5 nm. Further, by this heat treatment, the surface layer portion of the Cu · Mn alloy film in which Mn diffuses and escapes and Cu occupies substantially the entire amount and the Cu buried layer are integrated, and a wiring body made of Cu is formed.

The concentration distribution of Cu, Mn, and Si atoms inside the barrier layer was analyzed by electron energy loss spectroscopy (EELS). This EELS analysis was performed by scanning an electron beam at an interval of 0.2 nm using a high-resolution field emission transmission electron microscope (TEM). According to the analysis result, it was shown that the concentration of Cu atoms monotonously decreased from the wiring body toward the SiO ₂ insulating film side. It was also shown that the concentration of Si atoms monotonously decreased from the SiO ₂ insulating film toward the wiring body.

Further, according to TEM observation, almost no voids were found inside the barrier layer. For this reason, due to the uniform diffusion of Mn atoms, Mn atoms are concentrated in a region where the concentrations of Cu atoms and Si atoms substantially coincide. Further, the concentration of the accumulated Mn atoms was maximum in a region where the concentrations of Cu atoms and Si atoms in the barrier layer 7 substantially coincided with each other, and was about twice the concentration of Cu atoms and Si atoms.
When the electrical resistivity of the Cu wiring body was measured, the electrical resistivity was extremely low, which was 2.6 μΩ · cm, which is substantially equivalent to a wiring formed by embedding pure Cu in a wiring groove having an opening width of 90 nm.

As described above, according to the fifth embodiment of the present invention, as in the second embodiment, the barrier layer effective for suppressing diffusion provides a low-resistance Cu wiring close to a wiring made of pure Cu. I was able to. In addition, the insulating property of the insulating film can be improved by the barrier layer. Therefore, the wiring has a low resistance and can prevent the leakage of the element operating current, and a semiconductor device with low power consumption can be obtained. In addition, the reliability of the operation of the semiconductor device over a long period of time can be improved by improving the adhesion between the barrier layer and the wiring body and improving the adhesion between the barrier layer and the insulating film.
In Example 5, the heat treatment was performed for 90 minutes at 300 ° C. in a pure argon gas atmosphere inevitably containing only 0.1 ppm of oxygen. The same results as in Example 5 were obtained when the treatment was performed at 300 ° C. for 90 minutes in a nitrogen gas atmosphere containing hydrogen and an oxygen gas atmosphere inevitably containing only 0.1 ppm of oxygen.

(Example 6)
In this Example 6, the wiring structure provided with the barrier layer was formed in place of the opening width W of the wiring groove, as compared with Example 2 described above. The difference between the sixth embodiment and the second embodiment is as follows.

The opening width W was set to 32 nm, and the layer thickness of the Cu · Mn alloy film was set to 30 nm on the flat surface of the insulating film in which the wiring groove was not formed. At this time, a Cu · Mn alloy film of about 8 nm was formed on the groove bottom of the wiring groove.
In addition, the heat treatment for the Cu / Mn alloy film and the Cu buried layer left inside the wiring trench is performed in a pure argon gas atmosphere containing oxygen of 0.1 ppm for 30 minutes at a temperature of 350 ° C. It was something to do. By this heat treatment, Mn atoms contained in the alloy film were thermally diffused from the Cu / Mn alloy film toward the interface with the insulating film, and a barrier layer was formed in a region near the interface. The thickness of the formed barrier layer was 2 nm.

In Example 6, the concentration distribution of Cu, Mn, and Si atoms inside the barrier layer was analyzed by electron energy loss spectroscopy (EELS). This EELS analysis was performed by scanning an electron beam at an interval of 0.2 nm using a high-resolution field emission transmission electron microscope (TEM). According to the analysis result, it was shown that the concentration of Cu atoms monotonously decreased from the wiring body toward the SiO ₂ insulating film side. It was also shown that the concentration of Si atoms monotonously decreased from the SiO ₂ insulating film toward the wiring body.

  Further, according to TEM observation, almost no voids were found inside the barrier layer. For this reason, due to the uniform diffusion of Mn atoms, Mn atoms are concentrated in a region where the concentrations of Cu atoms and Si atoms substantially coincide. Further, the concentration of the accumulated Mn atoms was maximum in a region where the concentrations of Cu atoms and Si atoms in the barrier layer substantially coincided with each other, and was about twice the concentration of Cu atoms and Si atoms.

From the transmission electron microscopic image of the barrier layer after the above heat treatment, it was recognized that a random structure peculiar to amorphous was formed inside the barrier layer.
Moreover, as a result of acquiring the electron energy loss spectroscopy (EELS) spectrum of Mn from the area | region of a wiring main body, and the area | region of a barrier layer, Mn in the area | region adjacent to the barrier layer of a wiring main body is the same as the center part of a barrier layer. It was a valence, and it was confirmed that it was ionized to be divalent or trivalent.
When the electrical resistivity of the Cu wiring body was measured, the electrical resistivity was extremely low, which was 4.6 μΩ · cm, which was substantially equivalent to a wiring formed by embedding pure Cu in a wiring groove having an opening width of 32 nm.

As described above, according to the sixth embodiment of the present invention, as in the second embodiment, the barrier layer effective for suppressing diffusion provides a low-resistance Cu wiring close to a wiring made of pure Cu. I was able to. In addition, the insulating property of the insulating film can be improved by the barrier layer. Therefore, the wiring has a low resistance and can prevent the leakage of the element operating current, and a semiconductor device with low power consumption can be obtained. In addition, the reliability of the operation of the semiconductor device over a long period of time can be improved by improving the adhesion between the barrier layer and the wiring body and improving the adhesion between the barrier layer and the insulating film.
Further, according to Example 6, it was found that the present invention can be applied not only when the opening width of the wiring groove is 90 nm or 45 nm but also when the opening width is 32 nm, which is a narrower opening width.

  Next, a second embodiment and an example of the present invention will be described.

  FIGS. 9A and 9B are explanatory views schematically showing the manufacturing procedure and configuration of a semiconductor device according to the second embodiment of the present invention. FIG. 9A shows the first half of the manufacturing procedure, and FIG. 9B shows the second half of the manufacturing procedure. ing.

In the second embodiment shown in FIG. 9, the same reference numerals are given to substantially the same components as those in the first embodiment, and the description thereof is omitted. The second embodiment that is different from the first embodiment is the configuration of the barrier layer 7a, as shown on the right side of FIG. 9 (b), the barrier layer 7a is in the thickness direction center It is configured as a Mn-based oxide film that maximizes the atomic concentration of Mn at the portion, Cu is contained in the barrier layer 7a, and the atomic concentration of Cu is opposed to the wiring body 8 from the wiring body 8 side. It decreases monotonously toward the insulating film 3 side. In the barrier layer 7a, Si is not listed as a constituent requirement.
The layer thickness of the barrier layer 7a is 1 nm or more and is 1/5 or less of the opening width W of the wiring groove 4 provided in the insulating film 3 (see FIG. 9A) and 10 nm or less.
Further, bivalent or trivalent ionized Mn exists on the side of the wiring body 8 in contact with the barrier layer 7a.

Furthermore, in the second embodiment of the present invention, the heat treatment is performed using pure inert gas that inevitably contains oxygen (O ₂ ), or 75 vol. It is carried out in an air stream consisting of an inert gas containing ppm oxygen. Nitrogen gas or hydrogen gas containing oxygen (O ₂ ) inevitably only, or 75 vol. You may make it implement in the airflow which consists of nitrogen gas or hydrogen gas containing ppm oxygen.

According to the second embodiment of the present invention, the barrier layer 7a has a simpler structure than that of the first embodiment, but exhibits the following effects similar to those of the first embodiment. Can do.
That is, between the insulating film 3 and the wiring body 8, the barrier layer 7a made of a Mn-based oxide that maximizes the atomic concentration of Mn at the center of the layer thickness, that is, Mn is concentrated at the center of the layer thickness. Therefore, the barrier layer 7a is a thermally stable and structurally dense layer, and has an effective configuration for suppressing diffusion. For this reason, it has a favorable barrier property against the diffusion of Cu from the wiring body 8 side, and the insulating property of the insulating film 3 can be made excellent. Further, it has a good barrier property against the diffusion of Si from the insulating film 3 side, and the wiring body 8 can have a low resistance. Therefore, it is possible to provide a semiconductor device 1a with low power consumption by including wiring that can prevent leakage of element operating current with low resistance.

  Further, according to the second embodiment of the present invention, since the barrier layer 7a is a film containing Cu, the atomic concentration distribution is isolated between the barrier layer 7a and the wiring body 8 containing Cu as a main component. In this case, since the Cu concentration is continuously changed, the adhesion with the Cu film forming the wiring body 8 to be formed in contact with the surface of the barrier layer 7a can be improved. It is possible to make the device 1a excellent in operation reliability over a long period of time.

  Further, according to the second embodiment of the present invention, the atomic concentration of Cu in the barrier layer 7a is monotonously decreased from the side of the wiring main body 8 containing Cu as a main component toward the insulating film 3 side. Therefore, the atomic concentration distribution is not isolated between the barrier layer 7a and the wiring main body 8 containing Cu as a main component, and the Cu concentration continuously changes. Thus, it is possible to further improve the reliability of the operation of the semiconductor device 1a over a long period of time.

  According to the second embodiment of the present invention, the atomic concentration of Cu contained in the barrier layer 7a is set to be equal to or lower than the atomic concentration of Mn at the center in the thickness direction of the layer. Since the constituent element is Mn, and the Mn has a strong binding force with oxygen, it becomes a Mn oxide with a slow diffusion, and the barrier layer 7a is formed from the Mn oxide. For this reason, the barrier layer 7a exhibits an excellent barrier property against Cu diffusion from the wiring body 8 side.

  In addition, since the barrier layer 7a has a thickness of 1 nm or more and is 1/5 or less of the groove width of the opening to ensure the thickness of the barrier layer 7a, Cu diffusion or insulation from the wiring body 8 side is ensured. The barrier action of the barrier layer 7a against the diffusion of Si from the film 3 side is ensured. At the same time, since the thickness of the barrier layer 7a is 10 nm or less at the maximum, the wiring body 8 is narrowed by the barrier layer 7a, and adverse effects such as an increase in the effective electrical resistance of the wiring can be reliably prevented. . Therefore, the insulation of the insulating film 3 and the low resistance of the wiring can be obtained more reliably.

  Further, since the barrier layer 7a is made amorphous, it is possible to suppress abnormal diffusion of Cu and Si through the grain boundary. Therefore, the barrier action of the barrier layer 7a is improved, and the insulating property of the insulating film 3 and the low resistance of the wiring can be reliably maintained.

  Further, according to the second embodiment of the present invention, since Mn ionized bivalently or trivalently exists on the side of the wiring body 8 in contact with the barrier layer 7a, on the side of the wiring body 8 adjacent to the barrier layer 7a. There is a positive charge, and an electric field is formed between the barrier layer 7a and the insulating film 3 facing each other. Since the wiring body 8 and the insulating film 3 are attracted to the barrier layer 7a by the electric field formed on both sides of the barrier layer 7a, the effect of improving the adhesion at the interface can be obtained, and the semiconductor device 1a can be used for a long time. It is possible to achieve excellent reliability of the operation.

  Also, according to the second embodiment of the present invention, in the heat treatment step, the heat treatment is inevitably pure pure gas containing oxygen inevitably or 75 vol. Since it was performed in an inert gas containing a ratio of ppm, an appropriate amount of alloy elements such as Mn that diffused and moved to the surface of the wiring body 8 without being involved in the formation of the barrier layer 7a is contained in the inert gas. It is oxidized with a small amount of oxygen to form an oxide on the surface of the wiring body 8 and disappears from the inside of the wiring body 8 in the form of a surface oxide of the wiring body 8. Accordingly, the wiring resistance is substantially equal to that of pure Cu, and a low-resistance wiring main body can be obtained.

In the second embodiment of the present invention, since the heat treatment in the heat treatment step is performed at a temperature of 150 ° C. or higher and 600 ° C. or lower, the barrier layer 7a has a specific configuration according to the second embodiment of the present invention. Therefore, it is possible to bring about various effects such as lowering the resistance of the wiring body 8, improving the insulating property of the insulating film 3, and improving the adhesion to the wiring body 8 and the insulating film 3.
In the second embodiment of the present invention, the amorphization of the barrier layer 7a can be stably formed by performing the heat treatment in the heat treatment step at a temperature of 150 ° C. or higher and 450 ° C. or lower.

(Example)
The content of the second embodiment of the present invention is based on the Cu / Mn alloy film 5 on the insulating film 3 containing Si, the low-resistance wiring body 8 made of Cu, and the barrier layer 7a containing Cu and Mn. An example of forming a wiring structure including the above will be described in detail.

(Example 7)
FIG. 10 is a schematic diagram showing the internal structure of a wiring groove (opening) in a state where a Cu · Mn alloy film is deposited and then a Cu buried layer is deposited. FIG. 11 is a cross-sectional view showing the structure inside the wiring groove after the heat treatment is applied to the Cu · Mn alloy film and the Cu buried layer in the wiring groove. FIG. 12 is a transmission electron microscope image of a cross section of the barrier layer. FIG. 13 is a diagram showing an ion state of Mn element in the wiring body and the barrier layer. FIG. 14 shows the composition analysis results of Cu and Mn by electron energy loss spectroscopy (EELS) for the barrier layer.

As schematically shown in FIG. 10, the surface of the conductive silicon semiconductor layer 202 formed on the silicon substrate 201 is formed on the surface of SiO ₂ having a thickness of 150 nm, which is an interlayer insulator layer, by a general chemical vapor deposition method. A Cu · Mn alloy film 205 was deposited on the inner side wall and the surface of the wiring groove (opening) 204 on the insulating film 203 to be formed. The lateral width (opening width) W of the wiring groove 204 was 90 nm. The Cu · Mn alloy film 205 was formed by sputtering a target material made of a Cu · Mn alloy containing 7% of Mn at an atomic concentration in a general high-frequency sputtering apparatus. The ratio of atomic concentration of Mn in the obtained Cu · Mn alloy film 205 was quantified by the EELS method to be about 5%. The thickness of the Cu · Mn alloy film 205 was set to 80 nm when formed on the surface of a flat Si substrate.

  Next, the Cu · Mn alloy film 205 formed by sputtering is used as a seed layer (seed layer), and Cu is plated on the surface of the Cu · Mn alloy film 205 by an electrolytic plating method. A Cu buried layer 206 was formed inside 204 (see FIG. 8).

  Next, the structure including the Cu · Mn alloy film 205 and the Cu buried layer 206 in the wiring groove 204 of the insulating film 203 is set to 25 vol. Heat treatment was performed for 30 minutes at a temperature of 400 ° C. in an argon (Ar) atmosphere containing ppm. The rate of temperature increase from room temperature to 400 ° C. as the heat treatment temperature was 8 ° C. per minute. The average cooling rate from 400 ° C. to room temperature after finishing the heat treatment was 10 ° C. per minute. As a result, Mn atoms contained in the alloy film 205 are thermally diffused from the Cu / Mn alloy film 205 toward the interface with the insulating film 203, and a Mn-based oxide is formed in a region near the interface as shown in FIG. A barrier layer 207 made of was formed. The thickness of the barrier layer 207 formed by the heat treatment in this example was 5 nm.

  FIG. 12 shows a transmission electron microscope image of the barrier layer 207 after the above heat treatment. From FIG. 12, it was recognized that a random structure peculiar to amorphous was formed inside the barrier layer 207.

  In FIG. 12, an electron energy loss spectroscopy (EELS) spectrum of Mn was obtained from the portions indicated by regions a and b. The result is shown in FIG. A region a in FIG. 12 is a region adjacent to the barrier layer 207 in the wiring body 208, and a region b is a central portion of the barrier layer 207. In FIG. 13, in the Mn spectrum from the region a, the peak intensity is observed at the same energy position as the Mn spectrum from the central portion of the barrier layer 207 in the region b, even though the oxygen concentration is equal to or lower than the detection concentration by EELS. The From this, it was confirmed that Mn in the region adjacent to the barrier layer 207 of the wiring body 208 has the same valence as the central portion of the barrier layer 207 and is ionized to be bivalent or trivalent. .

  According to a general SIMS analysis, it was confirmed that Cu was contained inside the barrier layer 207. Further, it was confirmed that the concentration of Cu atoms monotonously decreased from the wiring body 208 side toward the insulating film 203 side.

FIG. 14 shows the result of analyzing the distribution of elements inside the barrier layer 207 by electron energy loss spectroscopy (EELS). A high-resolution field emission transmission electron microscope was used for the EELS analysis, and the composition was analyzed by scanning an electron beam at an interval of 0.2 nm. As apparent from FIG. 14, the Mn concentration showed the maximum value in the central portion of the barrier layer 207 in the layer thickness direction. Also in the EELS analysis, it was confirmed that the Cu concentration monotonously decreased from the film containing Cu as a main component (wiring body 208) to the insulating film 203 (SiO ₂ film). Further, the atomic concentration of Cu at the center of the thickness of the barrier layer 207 was less than or equal to the atomic concentration of Mn.

  Due to the above heat treatment, the Cu · Mn alloy film 205 in which Mn diffuses and escapes and Cu occupies substantially the entire amount and the Cu buried layer 206 are integrated to form the wiring body 208. As a result of the heat treatment, a Mn-based oxide film was formed on the upper surface layer of the wiring body 208 (not shown in FIG. 11). It was removed by mechanical polishing (abbreviation: CMP). After exposing the surface of the Cu wiring body 208, the electrical resistivity of the Cu wiring body 208 was measured. The electrical resistivity of the Cu wiring body 208 was extremely low, and was 2.5 μΩ · cm, which was substantially equivalent to a wiring formed by embedding pure Cu in a wiring groove having an opening width of 90 nm.

  As described above, according to Example 7 of the present invention, a low-resistance Cu wiring close to a wiring made of pure Cu could be provided by an amorphous barrier layer more effective for suppressing diffusion. . In addition, the insulating property of the insulating film can be improved by the barrier layer. Therefore, the wiring has a low resistance and can prevent the leakage of the element operating current, and a semiconductor device with low power consumption can be obtained. In addition, the reliability of the operation of the semiconductor device over a long period of time can be improved by improving the adhesion between the barrier layer and the wiring body and improving the adhesion between the barrier layer and the insulating film.

  The Cu wiring having the configuration of the present invention has a low resistance convenient for efficiently passing the element operating current, and also has a Mn-based oxide film sufficiently having a function as a barrier layer. Therefore, leakage of the element operating current can be avoided, and therefore, it can be suitably used to construct an electronic device with low power consumption. For example, it can be used to construct electronic devices such as a liquid crystal display device (LCD), a flat display device (abbreviation: FDP), an organic electroluminescence (abbreviation: EL) device, and an inorganic EL device.

  In addition, the Mn-based oxide film having a distribution in the atomic concentration of Mn described in the present invention does not need to form a thick barrier layer from a Ta-based material as in the prior art, and can function as a thin-film barrier layer. It can be used to construct a silicon LSI having a small wiring width, for example, a wiring width of 90 nm or less in order to integrate it to a high density.

  In addition, since the wiring according to the present invention is composed of a low resistance wiring body and a barrier layer that is convenient for preventing leakage of element operating current, silicon or It can be used to construct a power device made of silicon germanium (SiGe) or the like.

  Next, the sputtering target material used when the Cu alloy film 5 is deposited on the insulating film 3 by the sputtering method in the first and second embodiments will be described. Note that the composition of the Cu alloy film 5 formed by sputtering the sputtering target material is substantially the same as the composition of the sputtering target material used.

A sputtering target material used for depositing the Cu alloy film 5 is composed of copper (Cu) as a main component and manganese (Mn) as an essential element. Inevitable impurities that inevitably remain in the remaining Cu excluding s. And this inventor discovered that the malfunction of following (a)-(d) generate | occur | produces about the unavoidable impurity contained in this sputtering target material.
(A) When an inevitable impurity having a large free energy for forming an oxide and a high bonding reactivity with oxygen is present in the Cu alloy film, the inevitable impurity is easily combined with oxygen to become an oxide. Finally, the electrical resistance of the wiring body is increased by being taken into the wiring body.
(B) When inevitable impurities having a diffusion coefficient in Cu smaller than the self-diffusion coefficient of Cu are present in the Cu alloy film, the inevitable impurities tend to remain in Cu due to slow diffusion in Cu. Is finally taken into the wiring body and its electrical resistance increases.
(C) When unavoidable impurities forming an intermetallic compound with Cu are present in the Cu alloy film, the unavoidable impurities are finally taken into the wiring body and the electrical resistance is increased.
(D) When inevitable impurities that form an intermetallic compound with Mn are present in the Cu alloy film, the inevitable impurities are finally taken into the wiring body and the electrical resistance thereof is increased.

  Therefore, in the present invention, the inevitable impurities that cause the above-mentioned problems are specified and specified so as to hardly include them. And the wiring main body formed from this sputtering target material has low resistance and good conductivity, and can be a semiconductor device with low power consumption.

  As described above, this sputtering target material is composed of Cu as a main component, Mn as an essential element, and unavoidable impurities that inevitably remain in the remaining Cu excluding the essential elements.

  The content of Mn as an essential element is preferably 0.5% or more and 20% or less of the entire Cu alloy in terms of atomic concentration. The reason is that if it is 0.5% or less, Mn required for forming the barrier layer is small, so that a barrier layer having a thickness of 1 nm or less is formed at a part of the interface, and diffusion barrier properties and The adhesion of the interface cannot be secured. On the other hand, if it is 20% or more, the amount of Mn is so large that the thickness of the barrier layer becomes 10 nm or more, and there is no advantage over the current barrier layer such as Ta.

  In addition to Mn, zinc (Zn), germanium (Ge), strontium (Sr), silver (Ag), cadmium (Cd), indium (solid solution elements dissolved in Cu, which is the main component, are included in the essential elements. You may make it contain at least 1 element among each element of In, tin (Sn), barium (Ba), praseodymium (Pr), and neodymium (Nd). These solid solution elements are elements that have a diffusion constant equal to or larger than the self-diffusion coefficient of Cu and are more easily oxidized than Cu, and the wiring body side of the Mn-based oxide film as the barrier layer described above Therefore, it is possible to further improve the barrier property against Cu diffused from the substrate and the adhesion to the insulating film, and the semiconductor device can be excellent in operation reliability over a long period of time.

In the present invention, the inevitable impurities constitute lithium (Li) constituting the first group, beryllium (Be), calcium (Ca) and magnesium (Mg) constituting the second group, and the third group. Boron (B), gallium (Ga) and aluminum (Al), silicon (Si) constituting the fourth group, antimony (Sb) constituting the fifth group, scandium (Sc) constituting the sixth group, titanium ( Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium ( Tc), ruthenium (Ru), palladium (Pd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), i Indium (Ir), the main transition metal element of the platinum (Pt) and gold (Au), lanthanum constituting the seventh group (La), cesium (Ce), samarium (Sm), Gadori two um (Gd), terbium (Tb), dysprodium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) lanthanide transition metal elements, and constitute the eighth group In the case of any one of thorium (Th), the total content of the inevitable impurities is made atomic concentration for each group to be 0.1% or less of the entire copper alloy.

As described above, the sputtering target material of the present invention finally increases the electrical resistance of the wiring body 8 (a) has a large free energy for forming an oxide, and is free from oxygen. An impurity element having a high binding reactivity, (b) an impurity element having a diffusion coefficient in Cu smaller than the self-diffusion coefficient of Cu, (c) an impurity element forming an intermetallic compound with Cu, and (d) Mn and a metal Each concentration of the impurity element forming the intercalation compound is defined. By this concentration regulation, the concentration of a specific element that chemically reduces the interlayer insulating film 3 made of SiO ₂ is regulated, and the electrical resistivity of Cu is 5 μΩ · cm per 1% in terms of atomic concentration. Therefore, the concentration of the element to be raised over the range will be defined.

  Lithium (Li) constituting the first group belongs to Group I of the element periodic rule, and in the sputtering target material, this element is not included or is included, but the atomic concentration is 0.1% or less. Is preferred. Here, “not included” means that the concentration is below the analytical detection limit.

  Group I elements, particularly Li, have a high solid solubility in Cu, tend to remain in Cu (wiring body 8) and increase electrical resistance, and the liquidus temperature rapidly increases as the Li concentration increases. And liquid may ooze out during the process.

Here, 3 × 10 ⁻⁵ μg / ml is exemplified as the detection limit of Li in flameless atomic absorption spectrometry (Kazuo Yasuda, Yoshinosuke Hirokawa, “High Sensitive Atomic Absorption / Luminescence Analysis”, (See Kodansha Co., Ltd., issued July 10, 1976, first print, page 103). Similarly, the detection limit of Li in flame photoluminescence analysis is exemplified by 3 × 10 ⁻⁵ μg / ml (see “High-sensitivity atomic absorption / emission analysis” above, page 103). The weight concentration can be converted to the atomic concentration using the atomic weight of the target element (6.9 for Li).

  Beryllium (Be), calcium (Ca), and magnesium (Mg) constituting the second group belong to Group II of the element periodic rule, and these elements are not included or are included in the sputtering target material. However, the total atomic concentration is preferably 0.1% or less.

Since Be, Ca, and Mg are highly reactive with oxygen, if these elements are included in the sputtering target material in a total atomic concentration exceeding 0.1%, the Cu alloy film 5 Thus, the concentration of the oxide containing these elements increases remarkably. Since this oxide increases the electrical resistance of the Cu alloy, it does not lead to a Cu alloy film 5 suitable for providing a Cu film (wiring body 8) with high conductivity. On the other hand, if the atomic concentration of each element is suppressed to 0.1% or less, a Cu alloy film suitable for providing a Cu film (wiring body 8) with high conductivity can be stably obtained, and interlayer insulation can be obtained. Since the action of chemically reducing, for example, SiO ₂ forming the film 3 can also be suppressed, the amount of Si atoms generated due to the reduction can be reduced, and therefore the Cu film (wiring body 8) formed from the Cu alloy film 5 can be reduced. It is possible to reduce the amount of Si atoms that penetrate and increase the electrical resistance, and there is an advantage that a Cu film (wiring body 8) having high conductivity can be stably formed.

Here, 2 × 10 ⁻⁴ μg / ml is exemplified as the detection limit of Be in the high-frequency plasma spectroscopic analysis method (see “High-sensitivity atomic absorption / luminescence analysis” above, page 102). Moreover, 5.3 × 10 ⁻⁴ μg / ml is exemplified as the limit of detection of Ca in flameless atomic absorption spectrometry (see “High Sensitive Atomic Absorption / Luminescence Analysis”, page 102). Further, 2.8 × 10 ⁻⁶ μg / ml is exemplified as the detection limit of Mg in flameless atomic absorption spectrometry.

  Boron (B), gallium (Ga) and aluminum (Al) constituting the third group belong to Group III of the element periodic rule, and these elements are not included or are included in the sputtering target material. However, the total atomic concentration is preferably 0.1% or less.

  When the total concentration of each element of B, Ga, and Al constituting the third group is 0.1% or less, a Cu alloy film 5 that can provide a Cu film (wiring body 8) with high conductivity is obtained. be able to. These B, Ga, and Al have high reactivity with oxygen because the change in the free energy of formation or change in enthalpy of oxide is larger than that of, for example, Si oxide. If a large amount of oxides containing these elements are produced, it will not be possible to stably obtain a highly conductive Cu alloy film 5. The oxide containing these elements formed in the Cu alloy film 5 will eventually be taken into the Cu film, which hinders stable formation of a Cu film (wiring body 8) with high conductivity. Will come.

  And the density | concentration of the oxide formed in said Cu alloy film 5 increases naturally, so that content of B, Ga, and Al in the target material for sputtering increases. Further, since the melting point of boron (B) (= 2027 ° C.) is higher than the melting point of Cu (= 1082 ° C.) and its diffusion coefficient is smaller than the self-diffusion coefficient of Cu, most of the formed boron oxide is Cu It remains inside the alloy film 5. This hinders stable formation of a high conductivity Cu film (wiring body 8). Therefore, when the atomic concentration of B, Ga and Al is 0.1% or less in total, it is convenient to stably form a Cu film (wiring body 8) with high conductivity.

Here, 8 × 10 ⁻² μg / ml is exemplified as the detection limit of B in the high-frequency plasma spectroscopic analysis method (see “High-sensitivity atomic absorption / luminescence analysis” above, page 102). Moreover, 0.1 μg / ml is exemplified as the detection limit of Ga in flame absorption spectrometry (see “High-sensitivity atomic absorption / emission analysis” above, page 102). Moreover, 2 × 10 ⁻⁴ μg / ml is exemplified as the detection limit of Al in the high-frequency plasma spectroscopic analysis method (see “High-sensitivity atomic absorption / luminescence analysis” above, page 102).

Silicon (Si) constituting the fourth group belongs to Group IV of the element periodic rule, and in the sputtering target material, this element is not included or even if included, the atomic concentration is 0.1% or less. Is preferred.
When the atomic concentration of Si is 0.1% or more, it has an effect of increasing the electrical resistance of the Cu film (wiring body 8), and a low resistance Cu film (wiring body 8) cannot be stably formed.

Here, 9.4 × 10 ⁻² μg / ml is exemplified as the detection limit of Si in the high-frequency plasma spectroscopic analysis method using the absorbance at a wavelength of 256.1 nm (the above-mentioned “high-sensitivity atomic absorption / luminescence” Analysis ", page 104).

Antimony (Sb) constituting the fifth group belongs to the group V of the element periodic rule, and in the sputtering target material, this element is not included, or even if it is included, the atomic concentration is 0.1% or less. Is preferred.
If the atomic concentration of Sb is more than 0.1%, the Cu film (wiring body 8) has an effect of increasing the electric resistance, and a Cu film (wiring body 8) with good conductivity cannot be formed stably.

Here, the detection limit of Sb in the flameless atomic absorption spectrometry is exemplified as 5 × 10 ⁻³ μg / ml (see “High Sensitive Atomic Absorption / Emission Analysis”, page 104).

  Scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), yttrium (Y), zirconium (Zr) constituting the sixth group Niobium (Nb), Molybdenum (Mo), Technetium (Tc), Ruthenium (Ru), Palladium (Pd), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os) , Iridium (Ir), platinum (Pt), and gold (Au) each refers to an element group having a d shell (electron orbital) in which outer electrons are not sufficiently filled (“Daffy Inorganic Chemistry”). , Yodogawa Shoten Co., Ltd., published on April 15, 1971, 5th edition, p. 205), these elements are not included or included in the sputtering target material. There is also more than 0.1% by atomic concentration in the sum is preferred.

  Since each of these main transition metal elements has a low diffusion rate in Cu, Cu and the insulating layer are interdiffused before the sufficient amount of these elements reaches the interface in the Cu alloy film 5. Will deteriorate the characteristics. If the concentration of each element of these main transition metals exceeds 0.1% in total, the diffusion in Cu is slow and the tendency to remain in Cu is high and the electric resistance of Cu wiring is increased. . Furthermore, these elements are not preferable because they form an intermetallic compound with Mn, and thus have an effect of preventing Mn from diffusing to the interface or surface to form an electrical insulating layer.

  Therefore, if a sputtering target material having a total content of the above-mentioned main transition metal elements of 0.1% or less is used, it is particularly promoted that Mn diffuses to the interface and the surface to form an electrically insulating layer. This can contribute to the removal of elements that increase the electrical resistance of the wiring body 8.

Here, 2 × 10 ⁻⁴ μg / ml is exemplified as the detection limit of Ti in the high-frequency plasma spectroscopic analysis method (see “High-sensitivity atomic absorption / luminescence analysis” above, page 104). In addition, the detection limit of Fe is exemplified by 1 × 10 ⁻⁵ μg / ml in the frameless atomic absorption spectrometry, and 3 × 10 ⁻⁴ μg / ml in the high frequency plasma spectroscopy (see “ “High Sensitive Atomic Absorption / Emission Analysis”, page 102). The detection limits of other main transition metal elements are exemplified in well-known technical literature (for example, “High Sensitive Atomic Absorption / Luminescence Analysis”, pages 101 to 106) together with the definition of the detection limit.

Lanthanum constituting the seventh group (La), cesium (Ce), samarium (Sm), Gadori two um (Gd), terbium (Tb), Disperse propidium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutesium (Lu), each lanthanide transition metal element refers to an element group having an atomic number of 57 to 71 (see “Duffy Inorganic Chemistry” above, pages 262 to 263), These elements are not included in the sputtering target material, or even if included, the total atomic concentration is preferably 0.1% or less.

  If the total content of these elements is 0.1% or less, the formation of an intermetallic compound with Cu can be prevented, and a low resistance Cu film (wiring body 8) is formed. Can contribute.

Here, 4 × 10 ⁻⁴ μg / ml is exemplified as the detection limit of La in the high-frequency plasma spectroscopic analysis method (see “High-sensitivity atomic absorption / luminescence analysis” above, page 103). Moreover, 2 × 10 ⁻³ μg / ml is exemplified as the detection limit of Ce in the same analysis method (see “High-sensitivity atomic absorption / luminescence analysis” above, page 102). The detection limit of other transition metal elements in the lanthanide system can be known from technical literature (for example, “High-sensitivity atomic absorption / luminescence analysis”, pages 101 to 106).

Thorium (Th) constituting the eighth group, activators two de system in the transition metal elements ( "Duffy Inorganic Chemistry" mentioned above, pp. 265-267) is a one, this element, in the sputtering target material It is preferably not contained or 0.1% or less in terms of atomic concentration.
If the content of Th is 0.1% or less, formation of an intermetallic compound with Cu can be prevented, which can contribute to the formation of a low resistance Cu film (wiring body 8).

  Here, 2 μg / ml is exemplified as the detection limit of Th in the plasma jet method (see “High Sensitive Atomic Absorption / Emission Analysis” on pages 21 to 23) (see “High Sensitive Atomic Absorption / Emission” above). Analysis ", page 104).

  The sputtering target material according to the present invention, in which the content of the specific element (the first group to the eighth group) is specified to be low, has a high purity, for example, a purity of 99,9999 regardless of the production method and the purification method. Cu alloy produced by adding high-purity Mn with a purity of 99.999% (5N) or higher to Cu with a high purity of% (6N) or higher can be formed or processed into a plate shape. As high-purity Mn, for example, the total amount of metal impurities obtained by chelate resin ion exchange method, electric field method, vacuum sublimation purification method is 200 ppm or less, and the total amount of non-metal impurities is 10 ppm or less. The refined Mn can be used (see JP 2002-285373 A). For example, a Cu · Ge alloy can be manufactured by adding semiconductor grade high purity Ge to high purity Cu having a purity of 99,9999% (6N) or more.

The concentration of the specific element according to the present invention in the sputtering target material can be quantified by various high sensitivity analysis means. For example, it can be quantified by each means such as flameless atomic absorption analysis, high-frequency plasma spectroscopic analysis, and mass spectrometry. Quantitative analysis is preferably performed by selecting a means with a high detection limit (meaning that quantification is possible even at low concentrations) for each element to be analyzed. For example, for Ni, the detection limit in high-frequency plasma spectroscopy is 4.0 × 10 ⁻⁴ μg / ml, whereas the detection limit in flameless atomic absorption spectrometry is 7.3 × 10 ⁻⁵ μg. / Ml (see “High Sensitive Atomic Absorption and Luminescence Analysis” above, page 103). Therefore, it is desirable to quantify Ni by flameless atomic absorption spectrometry rather than high-frequency plasma spectroscopy.

  The Cu alloy produced by adding high-purity Mn to high-purity Cu can be used not only as a sputtering target material, but also as a vacuum evaporation source for forming wiring mainly composed of Cu, Further, it can be used as a film forming target material other than the sputtering method. For example, it can be used as a target material for a laser ablation method which is one film forming method of the Cu alloy film 5. Further, it can be used as a film forming target material for an ion plating method, an ion cluster beam method, a plasma reaction method and the like.

  As described above, the sputtering target material according to the present invention is a high-purity material in which the content of the specific elements is specified to be low, so that the occurrence of abnormal discharge during sputtering can be suppressed. The Cu film (wiring body 8) that forms a wiring body having a small number of cavities) and is uniform and has a uniform film thickness and the barrier layer 7 having a uniform film thickness can be produced even when stabilized.

In the above description, if the unavoidable impurities are specific elements constituting the first group to the eighth group, the total content of the unavoidable impurities is set to the atomic concentration for each group and the sputtering target material has a concentration of 0. The total content of the specific inevitable impurities may be 0.1% or less, instead of 0.1% or less for each group. By defining in this way, the inevitable impurities are further reduced, and the wiring body formed from the sputtering target material is made to have low resistance and good conductivity, and the effect of making a semiconductor device with low power consumption is further improved. It can be certain.
The present invention is a semiconductor element, a liquid crystal display device including the semiconductor element, a flat display device such as an organic and inorganic electroluminescence (abbreviation: EL) display device, and other electronic devices having a Cu wiring structure. In order to form the wiring, it can be widely applied as a sputtering target material.
Moreover, the Cu wiring structure produced using the sputtering target material according to the present invention is not limited to the damascene wiring structure described above, and can be applied to various wiring structures.

(Example 8)
The contents of the present invention will be described in detail by taking Cu wirings used for silicon (Si) semiconductor element applications as an example.

  FIG. 15 is a schematic diagram showing an internal structure of a wiring groove (opening) in a state where a Cu alloy film is deposited and then a Cu buried layer is deposited. FIG. 16 is a cross-sectional view showing the structure inside the wiring groove after the heat treatment is performed on the Cu alloy film and the Cu buried layer in the wiring groove.

As schematically shown in FIG. 15, the surface of a conductive silicon semiconductor layer 302 formed on a silicon substrate 301 is made of SiO ₂ having a thickness of 150 nm, which is an interlayer insulating layer, by a general chemical vapor deposition method. A Cu alloy film (Cu · Mn alloy film) 305 was deposited on the inner side wall and the surface of the wiring groove (opening) 304 on the insulating film 303 to be formed. The lateral width (opening width) W of the wiring groove 304 was 32 nm. The Cu · Mn alloy film 305 was formed by sputtering a sputtering target material according to the present invention containing 4% Mn in atomic concentration in a general high-frequency sputtering apparatus. The thickness of the Cu · Mn alloy film 305 was set to 30 nm when formed on the surface of a flat Si substrate.

The sputtering target material according to the present invention is obtained by molding a Cu alloy, and inevitable impurities contained in the sputtering target material include lithium (Li) and second material constituting the first group. Beryllium (Be), calcium (Ca) and magnesium (Mg) constituting the group, boron (B), gallium (Ga) and aluminum (Al) constituting the third group, silicon (Si) constituting the fourth group , Antimony (Sb) constituting the fifth group, scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (forming the sixth group) Ni), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), palladium (Pd , Hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt) and gold (Au) main transition metal elements, seventh group constitute a lanthanum (La), cesium (Ce), samarium (Sm), Gadori two Umm (Gd), terbium (Tb), disk dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) , Ytterbium (Yb) and lutetium (Lu), each of the lanthanide transition metal elements, and thorium (Th) constituting the eighth group. And the total content of the inevitable impurities was 0.1% or less in terms of atomic concentration for each group.

  Next, the Cu · Mn alloy film 305 formed by sputtering is used as a seed layer (seed layer), and Cu is plated on the surface of the Cu · Mn alloy film 305 by an electrolytic plating method to form a wiring groove. A Cu buried layer 306 was formed inside 304 (see FIG. 15).

  Next, the structure including the Cu · Mn alloy film 305 and the Cu buried layer 306 in the wiring groove 304 of the insulating film 303 is placed in an argon (Ar) atmosphere containing 10 ppm of oxygen by volume. Then, heat treatment was performed at a temperature of 300 ° C. for 15 minutes. The rate of temperature increase from room temperature to 300 ° C. as the heat treatment temperature was 8 ° C. per minute. Moreover, the average cooling rate from 300 degreeC to room temperature after finishing heat processing was 10 degreeC / min. Thus, Mn contained in the alloy film 305 is thermally diffused from the Cu / Mn alloy film 305 toward the interface with the insulating film 303, and the interface region is made of a Mn-based oxide as shown in FIG. A barrier layer 307 was formed. In the heat treatment in this example, the thickness of the formed barrier layer 307 was 4 nm.

According to general secondary ion mass spectrometry (SIMS), as in the case of the second embodiment, it is confirmed that Cu is contained in the barrier layer 307, and the concentration of Cu atoms of the barrier layer 30 7, that is decreasing monotonically it was confirmed from the wiring main body 308 side to the interlayer insulating film 303 side. Due to the heat treatment, the Cu / Mn alloy film 305 in which Mn diffuses and escapes and Cu occupies substantially the entire amount and the Cu buried layer 306 are integrated to form the wiring body 308. The electrical resistivity of the wiring body 308 was extremely low, and was 4.0 μΩ · cm, which was substantially equivalent to a wiring formed by embedding pure Cu in a wiring groove having an opening width of 32 nm.

Example 9
The inevitable impurities contained in the sputtering target material of Example 9 are lithium (Li) constituting the first group, beryllium (Be), calcium (Ca) and magnesium (Mg) constituting the second group, third Boron (B), gallium (Ga) and aluminum (Al) constituting the group, silicon (Si) constituting the fourth group, antimony (Sb) constituting the fifth group, titanium (Ti ), Vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), zirconium (Zr), molybdenum (Mo), palladium (Pd), tungsten (W), platinum (Pt) ) And gold (Au), and thorium (Th) constituting the eighth group. And the total content of the inevitable impurities was 0.1% or less in terms of atomic concentration for each group. The other conditions were the same as in Example 8 to form a wiring body. The electrical resistivity of the wiring body 308 was 4.0 μΩ · cm, the same value as in Example 8.

(Example 10)
Inevitable impurities contained in the sputtering target material of Example 10 are lithium (Li), beryllium (Be), calcium (Ca), magnesium (Mg), boron (B), gallium (Ga), and aluminum (Al). , Silicon (Si), antimony (Sb), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), yttrium (Y) , Zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), palladium (Pd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re) , Osmium (Os), iridium (Ir), platinum (Pt), gold (Au), lanthanum (La), cesium (C ), Samarium (Sm), Gadori two Umm (Gd), terbium (Tb), disk dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), And thorium (Th). And the total content of the inevitable impurities was 0.1% or less in terms of atomic concentration. The other conditions were the same as in Example 8 to form a wiring body. The electrical resistivity of the wiring body 308 was 3.8 μΩ · cm.

  In Example 10, the electrical resistance of the wiring body 308 could be improved to be lower. This is considered to be due to the fact that the content of specific inevitable impurities is not defined for each group but is defined as a whole, and as a result, the content is further reduced.

(Example 11)
Inevitable impurities contained in the sputtering target material of Example 11 are lithium (Li), beryllium (Be), calcium (Ca), magnesium (Mg), boron (B), gallium (Ga), and aluminum (Al). , Silicon (Si), antimony (Sb), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), zirconium (Zr), molybdenum (Mo) Palladium (Pd), tungsten (W), platinum (Pt), gold (Au), and thorium (Th). And the total content of the inevitable impurities was 0.1% or less in terms of atomic concentration. The other conditions were the same as in Example 8 to form a wiring body. The electrical resistivity of the wiring body 308 was the same value as in Example 10 and was 3.8 μΩ · cm.

(Comparative example)
The inevitable impurities contained in the sputtering target material of the comparative example are lithium (Li) constituting the first group, beryllium (Be), calcium (Ca) and magnesium (Mg) constituting the second group, and the third group. Boron (B), gallium (Ga) and aluminum (Al) constituting the fourth group, silicon (Si) constituting the fourth group, antimony (Sb) constituting the fifth group, scandium (Sc) constituting the sixth group , Titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo) Technetium (Tc), ruthenium (Ru), palladium (Pd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), Sumiumu (Os), iridium (Ir), the main transition metal element of the platinum (Pt) and gold (Au), lanthanum constituting the seventh group (La), cesium (Ce), samarium (Sm), Gadori two um (Gd), terbium (Tb), dysprodium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) lanthanide transition metal elements, and Any one of thorium (Th) constituting group 8, and the inevitable impurity exceeds 0.1% in atomic concentration in any of group 1 to group 8 (group 6 in this comparative example) Existed. The other conditions were the same as in Example 8 to form a wiring body. The electrical resistivity of the wiring body was 5.0 μΩ · cm. The increase in the electrical resistance of the wiring body is thought to be due to the large number of specific unavoidable impurities (sixth group in this comparative example).

  The semiconductor device according to the present invention has an insulating film containing silicon, a wiring body made of copper, and a barrier layer made of a Mn-based oxide, thereby ensuring insulation of the insulating film and reducing the resistance of the wiring. In addition, the adhesion between the barrier layer and the insulating film is improved, and a reliable operation is performed for a long time.

1A and 1B are explanatory views schematically showing the manufacturing procedure and configuration of a semiconductor device according to the present invention. FIG. 1A shows the first half of the manufacturing procedure, and FIG. 1B shows the second half of the manufacturing procedure. FIG. 2 is a cross-sectional view showing a stacked state before heat treatment in Example 1. FIG. 3 is a cross-sectional view showing a stacked state after the heat treatment in Example 1. FIG. 4 is a diagram showing the dependence of the resistivity of the wiring body on the heat treatment atmosphere and the heat treatment time. FIG. 5 is a schematic cross-sectional view of the semiconductor device before the heat treatment described in Example 2 in the first embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of the semiconductor device after the heat treatment described in Example 2 in the first embodiment of the present invention. FIG. 7 is a cross-sectional photograph of the barrier layer of the semiconductor device described in Example 2 in the first embodiment of the present invention. FIG. 8 is a diagram showing the concentration distribution of each atom in the amorphous barrier layer described in Example 3 in the first embodiment of the present invention. FIGS. 9A and 9B are explanatory views schematically showing a manufacturing procedure and configuration of a semiconductor device according to the second embodiment of the present invention. FIG. 9A shows the first half of the manufacturing procedure, and FIG. 9B shows the second half of the manufacturing procedure. Show. FIG. 10 is a schematic cross-sectional view showing a film deposition structure inside a wiring groove described in Example 7 in the second embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing the structure inside the wiring groove after the heat treatment described in Example 7 in the second embodiment of the present invention. FIG. 12 is a cross-sectional electron microscopic image of the barrier layer described in Example 7 in the second embodiment of the present invention. FIG. 13 is a diagram showing an ion state of Mn element in the wiring body and the barrier layer described in Example 7 in the second embodiment of the present invention. FIG. 14 is a diagram showing an elemental analysis result of the barrier layer described in Example 7 in the second embodiment of the present invention. FIG. 15 is a schematic cross-sectional view illustrating the structure inside the wiring groove in the first half of the manufacturing procedure of the semiconductor device according to the eighth embodiment. FIG. 16 is a schematic cross-sectional view showing the structure inside the wiring groove in the latter half of the manufacturing procedure of the semiconductor device according to the eighth embodiment.

Claims (19)

In a semiconductor device in which wiring is applied to an insulating film,
An insulating film containing silicon (Si);
A wiring body made of copper (Cu) formed in a groove-shaped opening provided in the insulating film;
A barrier layer made of a Mn-based oxide that is formed between the insulating film and the wiring body and maximizes the atomic concentration of manganese (Mn) at the center in the thickness direction;
A semiconductor device comprising:   The semiconductor device according to claim 1, wherein Cu is contained inside the barrier layer.   The semiconductor device according to claim 2, wherein the atomic concentration of Cu contained in the barrier layer monotonously decreases from the wiring body side toward the insulating film side.   4. The semiconductor device according to claim 3, wherein an atomic concentration of Cu contained in the barrier layer is equal to or lower than an atomic concentration of Mn at a central portion in a thickness direction of the barrier layer. In a semiconductor device in which wiring is applied to an insulating film,
An insulating film containing silicon (Si);
A wiring body made of copper (Cu) formed in a groove-shaped opening provided in the insulating film;
Formed between the wiring main body and the insulating film, the atomic concentration of Cu decreases monotonously from the wiring main body side toward the insulating film side, and the atomic concentration of Si monotonously decreases from the insulating film side toward the wiring main body side. A barrier layer made of an oxide containing Cu, Si and Mn, wherein the atomic concentration of Mn is maximized in a region where the atomic concentration of Cu and the atomic concentration of Si are substantially equal,
A semiconductor device comprising:   6. The semiconductor device according to claim 5, wherein the barrier layer has an atomic concentration of Mn in a region where the atomic concentrations of Cu and Si inside thereof are substantially equal to or more than twice the atomic concentration of Cu or Si. The barrier layer is 1/5 or less of the groove width of the opening in the layer thickness 1nm or more, and is 10nm or less, the semiconductor device according to any one of claims 1 to 6.   The semiconductor device according to claim 1, wherein the barrier layer is made of an amorphous material.   9. The semiconductor device according to claim 1, wherein Mn ionized bivalently or trivalently exists on the side of the wiring main body in contact with the barrier layer. In a method for manufacturing a semiconductor device in which wiring is applied to an insulating film,
Providing a groove-like opening in an insulating film containing silicon (Si);
A copper alloy film forming step of forming a copper alloy film containing manganese (Mn) and copper (Cu) on the inner peripheral surface of the opening;
A step of burying Cu in the opening in which the copper alloy film is formed to form a copper buried layer;
Heat treatment, forming a barrier layer between the copper alloy film and the insulating film, and having the copper alloy film integrated with Cu of the copper embedded layer to form a wiring body,
The barrier layer is made of a Mn-based oxide that maximizes the atomic concentration of Mn at the center in the thickness direction.
A method for manufacturing a semiconductor device. In a method for manufacturing a semiconductor device in which wiring is applied to an insulating film,
Providing a groove-like opening in an insulating film containing silicon (Si);
A copper alloy film forming step of forming a copper alloy film containing manganese (Mn) and copper (Cu) on the inner peripheral surface of the opening;
A step of burying Cu in the opening in which the copper alloy film is formed to form a copper buried layer;
Heat treatment, forming a barrier layer between the copper alloy film and the insulating film, and having the copper alloy film integrated with Cu of the copper embedded layer to form a wiring body,
In the barrier layer, the atomic concentration of Cu decreases monotonously from the wiring body side toward the insulating film side, the atomic concentration of Si decreases monotonously from the insulating film toward the wiring body side, and the Cu atomic concentration and Si Made of an oxide containing Cu, Si and Mn, in which the atomic concentration of Mn is maximized in a region where the atomic concentration of Cu is substantially equal.
A method for manufacturing a semiconductor device.   In the above heat treatment step, the heat treatment inevitably contains pure inert gas containing oxygen or oxygen up to 75 vol. The manufacturing method of the semiconductor device of Claim 10 or 11 performed in the airflow which consists of an inert gas contained in the ratio of ppm.   In the above heat treatment step, the heat treatment inevitably contains nitrogen gas or hydrogen gas containing oxygen, or oxygen at a maximum of 75 vol. The manufacturing method of the semiconductor device of Claim 10 or 11 performed in the airflow which consists of nitrogen gas or hydrogen gas contained in the ratio of ppm.   The method for manufacturing a semiconductor device according to claim 10, wherein in the heat treatment step, the heat treatment is performed at a temperature of 150 ° C. or more and 600 ° C. or less.   14. The method of manufacturing a semiconductor device according to claim 10, wherein in the heat treatment step, the heat treatment is performed at a temperature of 150 ° C. or higher and 450 ° C. or lower.   The method of manufacturing a semiconductor device according to claim 10, wherein the formation of the copper alloy film in the copper alloy film forming step is performed by sputtering a sputtering target material. A sputtering target material used in the method for producing a semiconductor device according to claim 16, wherein the sputtering alloy material is formed by performing sputtering.
Copper (Cu) as a main component;
Manganese (Mn) as an essential element,
It consists of inevitable impurities that inevitably remain in the remaining Cu excluding the essential elements,
The inevitable impurities include lithium (Li) constituting the first group, beryllium (Be), calcium (Ca) and magnesium (Mg) constituting the second group, boron (B) constituting the third group, and gallium. (Ga) and aluminum (Al), silicon (Si) constituting the fourth group, antimony (Sb) constituting the fifth group, scandium (Sc) constituting the sixth group, titanium (Ti), vanadium (V ), Chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru) ), Palladium (Pd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), white (Pt) and the main transition metal element of gold (Au), lanthanum constituting the seventh group (La), cesium (Ce), samarium (Sm), Gadori two um (Gd), terbium (Tb), Disperse dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu) transition metal elements in each lanthanide system, and thorium (Th) constituting the eighth group The total content of the inevitable impurities is atomic concentration for each group and 0.1% or less of the entire target material,
A sputtering target material characterized by the above. A sputtering target material used in the method for producing a semiconductor device according to claim 16, wherein the sputtering alloy material is formed by performing sputtering.
Copper (Cu) as a main component;
Manganese (Mn) as an essential element,
It consists of inevitable impurities that inevitably remain in the remaining Cu excluding the essential elements,
The inevitable impurities are lithium (Li), beryllium (Be), calcium (Ca), magnesium (Mg), boron (B), gallium (Ga), aluminum (Al), silicon (Si), and antimony (Sb). , Scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), yttrium (Y), zirconium (Zr), niobium (Nb) Molybdenum (Mo), technetium (Tc), ruthenium (Ru), palladium (Pd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir) , platinum (Pt), gold (Au), lanthanum (La), cesium (Ce), samarium (Sm), Gadori two Umm (Gd) If it is any of terbium (Tb), dysprodium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutesium (Lu), and thorium (Th), it is inevitable. The total content of mechanical impurities is made atomic concentration and 0.1% or less of the entire target material,
A sputtering target material characterized by the above.   19. The sputtering target material according to claim 16, wherein the content of Mn as the essential element is 0.5% or more and 20% or less of the whole target material in terms of atomic concentration.

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