JP2008060414A - Semiconductor device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device for improving the reliability by preventing a conductive member from being oxidized, and to provide a manufacturing method of the semiconductor device. <P>SOLUTION: A first insulating layer 100 is formed on a semiconductor substrate; a groove 107 is formed on the first insulating layer 100; a wiring layer 101 containing copper on the surface is formed in the groove 107; the surface of the wiring layer 101 is activated to form a cap film 105, containing cobalt on the surface of the wiring layer 101 by subjecting it to electroless plating method; plasma treatment is performed on the surface of the wiring layer 101, excluding the forming section of the cap film 105 by reactive gas containing silicon and nitrogen; a copper silicide film 106 containing nitrogen is formed; and a second insulating layer 103 is formed on the first insulating layer 100, the cap film 105, and the copper silicide film 106 containing nitrogen. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a semiconductor device and a manufacturing method thereof.

In recent years, in a semiconductor device having a fine wiring structure such as an LSI (Large Scale Integrated circuit), a copper wiring mainly composed of copper is widely used in order to reduce wiring resistance and improve reliability. In a semiconductor device using copper wiring, deterioration of wiring characteristics due to wiring oxidation becomes a problem. Therefore, an anti-oxidation protective film is connected to the copper wiring so that the insulating film containing oxygen is not in direct contact with the copper wiring. It is necessary to form a film between insulating films. At the same time, a protective film with high adhesion to the copper wiring is formed on the copper wiring interface in order to prevent deterioration of wiring characteristics due to electromigration (hereinafter referred to as EM) due to copper diffusion at the copper wiring interface. There is also a need to membrane.

  On the other hand, wiring characteristics due to oxidation of the wiring surface by forming a cap film containing cobalt that has high anti-oxidation effect and high adhesion to the copper wiring interface by the electroless plating method on the copper wiring. There is known a semiconductor device that prevents deterioration and further improves EM resistance (see, for example, Patent Document 1).

However, when the cap film is formed on the wiring by the electroless plating method, it is difficult to uniformly form the cap film on the entire copper wiring surface, so that the entire copper wiring surface is securely covered with the cap film. It may not be possible. For this reason, the oxidation of the copper wiring surface cannot be sufficiently prevented, and the EM resistance cannot be further improved, so that there is a possibility that the reliability of the semiconductor device cannot be ensured.

On the other hand, when a copper wiring fuse is formed in the semiconductor device, the fuse melting section may be corroded due to oxidation of the exposed fuse melting section, thereby impairing the reliability of the semiconductor device.

Furthermore, when a bonding wire is connected to the conductor pad of the semiconductor device, the exposed conductor pad surface excluding the bonding wire forming portion may be oxidized and corroded. At present, there is known a conventional technique for forming aluminum or the like on a conductor pad to prevent oxidation, but there is a problem that the manufacturing process increases and the manufacturing cost increases, and a simple and inexpensive method is used. It is difficult to improve the reliability of the semiconductor device by preventing the pad surface from being oxidized.
JP 2003-179000 (FIG. 1)

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a semiconductor device and a manufacturing method thereof in which the reliability of the conductive member is improved by preventing oxidation of the conductive member.

In order to achieve the above object, a method for manufacturing a semiconductor device of one embodiment of the present invention includes a step of forming a first insulating layer over a semiconductor substrate, forming a groove in the first insulating layer, and forming the groove. Forming a copper-containing wiring layer on the surface; forming a cobalt-containing cap film on the wiring layer surface; and nitrogen-containing copper silicide on the wiring layer surface excluding the cap film forming portion A step of forming a film is provided.

According to another aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: forming a first insulating layer on a semiconductor substrate; forming a groove in the first insulating layer; and forming a groove in the groove. A step of forming a wiring layer containing copper, a step of forming a nitrogen-containing copper silicide film on the surface of the wiring layer, and a step of forming a cap film containing cobalt on the surface of the nitrogen-containing copper silicide film. It is characterized by that.

According to another aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: forming a first insulating layer on a semiconductor substrate; forming a groove in the first insulating layer; and forming copper on the surface of the groove. A step of forming a wiring layer containing copper, a step of forming a nitrogen-containing copper silicide film on the surface of the wiring layer, and a step of forming a cap film containing cobalt on the surface of the nitrogen-containing copper silicide film. It is characterized by having.

According to another aspect of the present invention, there is provided a semiconductor device including: an interlayer insulating layer formed over a semiconductor substrate; a wiring layer containing copper on a surface formed in the interlayer insulating layer; And a cobalt-containing cap silicide film formed on the surface of the wiring layer excluding the cap film forming portion.

According to another aspect of the present invention, there is provided a semiconductor device including an opening formed in an insulating layer on a semiconductor substrate, a copper-containing member whose surface is exposed in the opening, and an exposed surface of the copper-containing member. A nitrogen-containing copper silicide film is provided.

According to the present invention, it is possible to provide a highly reliable semiconductor device by preventing oxidation of the conductive member.

A semiconductor device and a manufacturing method thereof according to embodiments of the present invention will be described below with reference to the drawings.

First, the configuration of the semiconductor device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the main part of the semiconductor device according to this embodiment.

  In the semiconductor device according to the present embodiment, an interlayer insulating layer composed of a silicon oxide film or the like is laminated on a semiconductor substrate such as a silicon substrate (not shown), and fine plugs and fine wiring layers are formed in the interlayer insulating layer. Each has a multi-layered wiring structure formed by stacking. In this embodiment, the fine plug and the fine wiring layer are made of copper or a copper alloy as a constituent material.

As shown in FIG. 1, in the semiconductor device according to the present embodiment, a wiring layer 101 disposed at a predetermined design position is formed on a predetermined interlayer insulating layer 100 (first insulating layer 100). A barrier film 102 of titanium nitride, tantalum nitride, titanium, tantalum, or the like is formed on the side surface and the bottom surface of the wiring layer 101, and the barrier film 102 allows the first adjacent to the wiring layer 101 from the wiring layer 101. Diffusion of the copper component into the insulating layer 100 or the like is suppressed.

Further, an upper interlayer insulating layer 103 (second insulating layer 103) is formed on the first insulating layer 100, and a plug 104 is disposed above and below the second insulating layer 103 in the second insulating layer 103. It is formed to penetrate. The plug 104 is formed on the wiring layer 101 and has a function of electrically connecting the wiring layer 101 and an upper wiring layer (not shown). In addition, a barrier film 102 for preventing diffusion of a copper component into the second insulating layer 103 is also formed on the side surface and the bottom surface of the plug 104.

  A cap film 105 is formed on the wiring layer 101 at the interface between the wiring layer 101 and the second insulating layer 103 or the plug 104. The cap film 105 is a thin film high melting point metal containing cobalt as a component formed by electroless plating. For example, a cobalt compound in which a metal component such as tungsten is added to cobalt, CoWB, CoWP, CoWBP, CoBP, CoB, CoP, etc. The cap film 105 is a thin film having an anti-oxidation function and high adhesion to the copper surface of the wiring layer 101. Therefore, by forming the cap film 105 on the wiring layer 101, it is possible to suppress the oxidation of the surface of the wiring layer 101 by avoiding the exposure of the oxidizing gas to the surface of the wiring layer 101 and the invasion of moisture. Further, the EM resistance can be improved by preventing the diffusion of the copper component at the interface between the surface of the wiring layer 101 and the second insulating layer 103.

However, as shown in FIG. 1, the cap film 105 formed on the wiring layer 101 by the electroless plating method is very difficult to form a uniform film on all wiring surfaces. It is difficult to reliably cover the entire surface with the cap film 105. That is, a portion of the surface of the wiring layer 101 that is not covered with the cap film 105 exists due to the collapse of the film formation of the cap film 105 at the end of the wiring layer 101 or the generation of voids in the cap film 105. . Therefore, a part of the surface of the wiring layer 101 that is not covered with the cap film 105 is easily oxidized, and there is a concern that the EM resistance may deteriorate.

Therefore, in the semiconductor device according to the present embodiment, the copper component on the surface of the wiring layer 101 is silicided on the surface of the wiring layer 101 not covered with the cap film 105 in order to reliably prevent oxidation on the entire surface of the wiring layer 101. A nitrogen-containing copper silicide film 106 subjected to nitriding treatment is formed. The nitrogen-containing copper silicide film 106 exposes the surface of the wiring layer 101 to a reactive gas containing silicon, for example, silane gas, and permeates silicon atoms from the surface of the copper wiring layer 101 into the copper wiring layer 101 to form a copper silicide thin film. And an insulating film formed by nitriding the copper silicide film by performing plasma treatment on the surface of the wiring layer 101 using a reactive gas containing nitrogen, for example, ammonia gas.

The nitrogen-containing copper silicide film 106 is a film having lower adhesion to the copper surface of the wiring layer 101 than the cap film 105, but has a good film quality and can be easily formed uniformly. It is. Therefore, by forming the nitrogen-containing copper silicide film 106 on the surface of the wiring layer 101 not covered with the cap film 105, the entire surface of the wiring layer 101 is surely covered with both the cap film 105 and the nitrogen-containing copper silicide film 106. Thus, oxidation of the copper wiring layer 101 surface and EM on the copper wiring layer 101 surface can be effectively prevented.

In the semiconductor device according to the present embodiment, an interlayer insulating layer such as a silicon oxide film is stacked on a semiconductor substrate such as single crystal silicon on which an element or the like is formed using a CVD method or the like. It is manufactured by forming a wiring circuit by forming a wiring material such as a wiring layer and a plug at a predetermined design position.

Hereafter, with reference to FIG. 2, a method of manufacturing a wiring layer formed in the interlayer insulating layer of the semiconductor device according to the present embodiment will be described. FIG. 2 is a process cross-sectional view illustrating the manufacturing method of the main part of the semiconductor device according to the present embodiment.

First, as shown in FIG. 2A, an interlayer insulating layer formed with, for example, a wiring layer or a conductive plug is laminated on a semiconductor substrate (not shown), and then a predetermined interlayer insulating layer 100 is formed by a CVD method or the like. (First insulating layer 100) is formed. Further, a resist film (not shown) is formed on the interlayer insulating layer 100 by photolithography, a pattern for wiring formation is formed on the resist film, and then the resist film is masked by RIE (Reactive Ion Etching). Then, the first insulating layer 100 is removed by etching, and a groove 107 for forming the wiring layer 101 is formed in the first insulating layer 100. Here, in FIG. 2, a wiring region with a sparse wiring density is shown on the left side as viewed on the paper surface, and a wiring region with a dense wiring density is shown on the right side as viewed on the paper surface.

  Next, as shown in FIG. 2B, the diffusion prevention of the wiring material such as titanium nitride or tantalum nitride is performed on the first insulating layer 100 and inside the wiring forming groove 107 by sputtering or the like. By sequentially forming a barrier film material for wiring and a wiring material mainly composed of copper, and further polishing and removing the wiring material and the barrier film material outside the wiring forming groove 107 by CMP (Chemical Mechanical Polishing). A wiring layer 101 and a barrier film 102 are formed inside the first insulating layer 100.

  Next, as shown in FIG. 2C, a cap film 105 containing cobalt for preventing oxidation of the surface of the wiring layer 101 and improving EM resistance, for example, CoWB, on the wiring layer 101 by using an electroless plating method. , CoWP, CoBP, etc. are formed in a self-aligning manner. Here, a specific method for forming the cap film 105 will be described below.

First, the surface of the first insulating layer 100 where the wiring layer 101 is exposed is immersed in a palladium chloride aqueous solution containing a metal element having a smaller ionization tendency than copper, for example, palladium, so that the copper atoms on the surface of the wiring layer 101 are replaced with palladium atoms. Then, a palladium plating layer is formed in a self-aligned manner only on the surface of the copper wiring layer 101. The palladium plating layer functions as a catalyst active layer, and the process of forming the substitution metal plating layer on the surface of the wiring layer 101 in this way is referred to as the activation process of the surface of the wiring layer 101.

Furthermore, after the activation treatment was performed on the surface of the wiring layer 101, cobalt was included as a constituent component in the catalytic active layer forming portion on the surface of the wiring layer 101 by an electroless plating method using a plating solution containing a cobalt chloride aqueous solution or the like. The cap film 105 is formed in a self-aligning manner. Since the cap film 105 according to the present embodiment has a higher degree of adhesion with the surface of the copper wiring layer 101 than the general cap film 105 made of a silicon carbide film, a silicon nitride film, or the like, the wiring layer 101 Surface oxidation can be more effectively prevented, and the EM resistance of the surface of the wiring layer 101 can be improved.

At this time, since the catalytically active layer is not formed on the first insulating layer 100 that does not contain the metal to be substituted and the catalytically active layer is formed only on the surface of the copper wiring layer 101, the cap film 105 is made of copper. It is formed only on the wiring layer 101. Normally, when a conductive cap film is formed on the wiring layer 101 using the CVD method or the like, the cap film other than on the copper wiring layer or in the vicinity thereof is removed by, for example, photolithography and RIE after the film formation. However, since the cap film 105 according to the present embodiment is selectively formed only on the copper wiring layer 101, the cap film 105 removal step is unnecessary and the manufacture is easy. .

The cap film 105 can also be formed by other electroless plating methods. That is, after polishing the copper wiring layer 101 by the CMP process, using a chemical solution that reacts with an acid chemical solution, for example, a copper oxide such as citric acid, hydrochloric acid, dilute sulfuric acid, and does not significantly damage copper. After activating the surface of the copper wiring layer 101 by removing the oxide on the surface of the copper wiring layer 101, etc., sulfuric acid-based cobalt (Co) containing boron or phosphorus at about 50 to 150 ° C. under a nitrogen forming gas. ) A chemical solution is supplied onto the surface of the copper wiring layer 101.

At this time, for example, when boron (B) is used as a catalyst, the boron oxide becomes B ³⁺ by giving trivalent electrons to copper (Cu), and the surface of the copper wiring layer 101 is made of electrons given by boron. Negative charge accumulates. Co ²⁺ in the sulfuric acid chemical solution is attracted to the surface of the copper wiring layer 101 and accumulated on the surface of the copper wiring layer 101, and a cobalt film 105 (cap film 105) is formed on the surface of the copper wiring layer 101. On the other hand, since boron cannot give electrons to the insulating layer 100, the cobalt film 105 is not formed on the insulating layer 100, and selective film formation can be performed only on the surface of the copper wiring layer 101.

After forming the high melting point cap film 105 containing cobalt in this manner, the surface of the copper wiring layer 101 is formed using an acid chemical solution (sulfuric acid, hydrofluoric acid, phosphoric acid, hydrochloric acid, etc.) at a temperature of about room temperature. Washing is performed to remove the plating solution residue and stabilize the surface of the cobalt-containing cap film 105.

By the electroless plating method as described above, the cap film 105 having high adhesion can be formed on the surface of the wiring layer 101. On the other hand, it is very difficult to uniformly form the cap film 105 on the wiring layer 101. The entire surface of the wiring layer 101 cannot be reliably covered with the cap film 105 due to selection failure or void formation in the film formation, and a part of the wiring layer 101 is exposed. In some cases, the oxidation of the layer 101 cannot be sufficiently prevented.

In addition, the formation speed of the cap film 105 formed on the wiring layer 101 by the electroless plating method may differ depending on the wiring density in the wiring layer 101 forming region. That is, as shown in FIG. 2, the film formation speed is slow on the wiring layer 101 in the area where the wiring density is sparse, and conversely, the film formation speed tends to be high on the wiring layer 101 in the area where the wiring density is dense. Is seen. For this reason, the cap film 105 on the wiring layer 101 inside the semiconductor device is not formed with a uniform thickness as a whole, and in the wiring region where the thickness of the conductive cap film 105 is locally increased, the adjacent wiring layer or In the wiring region where the cap film 105 is locally thinned, the surface of the wiring layer 101 can be reliably covered with the cap film 105. Therefore, there is a possibility that oxidation of the surface of the wiring layer 101 cannot be sufficiently prevented.

Therefore, next, in order to solve the above-described problem, as shown in FIG. 2D, a nitrogen-containing copper silicide film 106 is formed in a self-aligned manner on the exposed surface of the wiring layer 101 not covered with the cap film 105. Thus, the entire surface of the wiring layer 101 is covered to prevent the surface of the wiring layer 101 from being oxidized.

Specifically, after forming the cap film 105 on the surface of the wiring layer 101, first, the semiconductor device is held in a low pressure chamber maintained in a constant high temperature atmosphere of about 200 ° C. to 400 ° C. Silane gas is exposed to the surface portion, and silicon is infiltrated into the copper wiring from the copper wiring surface to form a copper silicide film. Further, while maintaining a constant low pressure state, ammonia gas is supplied, an ammonia plasma treatment is performed by applying a high-frequency electric field, and the copper silicide film forming portion on the copper surface of the wiring layer 101 is nitrided in a self-aligned manner. A nitrogen-containing copper silicide film 106 is formed. Note that silicon in the surface layer of the copper wiring layer 101 may diffuse into the copper wiring 101 through the heat treatment process and increase the wiring resistance. Therefore, sufficient nitridation is performed to form a stable nitrogen-containing copper silicide film 106. It will be necessary.

The nitrogen-containing copper silicide film 106 is a thin film having a good film quality that can be formed more uniformly than the cap film 105. Therefore, the surface of the wiring layer 101 exposed by generation of voids in the cap film 105 can be reliably covered with the nitrogen-containing copper silicide film 106.

As a result, the surface of the wiring layer 101 is mostly covered with the cap film 105 having high EM resistance, and the surface of the wiring layer 101 not covered with the cap film 105 is covered with the nitrogen-containing copper silicide film 106. It becomes possible to effectively prevent the surface of the wiring layer 101 from being oxidized and to form a wiring excellent in EM resistance.

Further, in the process shown in FIGS. 2C and 2D, when the cap film 105 is formed on the wiring layer 101 having a high film density and a high wiring density, the cap film 105 is formed. Next, the nitrogen-containing copper silicide film 106 is formed on the surface of the wiring layer 101.
As a result, the cap film 105 is prevented from being excessively formed on the wiring layer 101 having a high film formation speed and a high wiring density, and an electrical short circuit between adjacent wiring layers 101 can be prevented. Even if the cap film 105 is not sufficiently formed on the surface of the wiring layer 101 having a low wiring density, the surface of the wiring layer 101 is covered with the nitrogen-containing copper silicide film 106. Oxidation can be effectively prevented.

In addition, although the wiring layer 101 having a high wiring density may have a reduced EM resistance, it is possible to form a cap film 105 excellent in the EM resistance with respect to the strict wiring layer 101 in the EM. .

As a conventional technique for preventing oxidation of the wiring layer, a conventional technique for preventing oxidation of the wiring layer or the like by laminating a cap film containing cobalt on the wiring layer by an electroless plating method is known. However, according to this prior art, voids and the like may occur in the cap film containing cobalt. Therefore, the wiring layer surface cannot be reliably covered with the laminated cap film, so that the wiring layer is sufficiently oxidized. There is a risk that it cannot be prevented.

As another conventional technique, there is a conventional technique in which only the above-described nitrogen-containing copper silicide film is formed on the surface of the wiring layer to prevent oxidation of the wiring layer surface, to prevent leakage of copper into the insulating film, and to improve EM resistance. Are known. On the other hand, in the semiconductor device according to this example, most of the surface of the wiring layer 101 is formed by the cap film 105 containing cobalt having higher adhesion to the copper wiring interface and higher EM diffusion activation energy than the nitrogen-containing copper silicide film 106. EM resistance is strengthened by covering. Therefore, according to the semiconductor device according to the present embodiment, the oxidation of the wiring layer surface can be effectively prevented and the EM resistance can be enhanced as compared with the semiconductor device using this conventional technique.

Furthermore, as another conventional technique, the above-described nitrogen-containing copper silicide film is formed on the surface of the wiring layer without forming a cap film on the wiring layer, and a silicon nitride film is further formed on the nitrogen-containing copper silicide film by a CVD method. Alternatively, a conventional technique for forming a silicon carbide film to prevent oxidation of the wiring layer surface is known. However, since the silicon nitride film or silicon carbide film has a lower degree of adhesion to the copper wiring layer surface than the nitrogen-containing copper silicide film 106 according to the present embodiment, it cannot be said that the EM resistance of the wiring is sufficient. When the conventional silicon nitride film formed by the CVD method is used in combination, the silicon nitride film having a large capacitance covers the entire circuit surface, so that there is a possibility that the performance of the semiconductor device is deteriorated due to a signal delay accompanying an increase in the capacitance between wirings. . Further, in the semiconductor device using this prior art, when a silicon nitride film or a silicon carbide film is left only on or in the vicinity of the wiring layer to reduce the capacitance between the wirings, the silicon nitride film or silicon carbonization by the CVD method is used. Since the silicon nitride film or the silicon carbide film needs to be processed by photolithography and RIE after the film is formed, the manufacturing process is significantly larger than the process of forming the nitrogen-containing copper silicide film 106 according to this embodiment. Increased manufacturing costs.

Therefore, the antioxidant film on the surface of the wiring layer 101 composed of the cap film 105 and the nitrogen-containing copper silicide film 106 according to the present example has a higher antioxidant effect than the antioxidant film of the wiring layer according to the prior art. It can be said that the EM resistance is excellent, the formation thereof is easy, and the reduction of the capacity can be realized.

Next, after forming the cap film 105 and the nitrogen-containing copper silicide film 106, as shown in FIG. 2E, an upper interlayer insulating layer is formed on the first insulating layer 100 by using a CVD method or the like. A second insulating layer 103 is formed. Further, although illustration is omitted, after a hole is formed in the second insulating layer 103 by photolithography and RIE, a plug electrically connected to the wiring layer 101 is embedded in the hole.

According to the semiconductor device manufactured by the above process, the wiring layer 101 is mostly covered with the cap film 105 having high EM resistance at the interface between the wiring layer 101 and the second insulating layer 103. Since the nitrogen-containing copper silicide film 106 with good film quality is formed on the surface portion not covered with the film 105, the surface of the wiring layer 101 can be effectively prevented from being oxidized, and the reliability of the semiconductor device Can be improved.

In the semiconductor device manufacturing method according to this embodiment described above, after forming the cap film 105 once as shown in FIG. 2C, the surface of the wiring layer 101 where the cap film 105 was not formed is activated again. Processing may be performed, and the cap film 105 may be formed again on the surface of the wiring layer 101. In this case, since almost the entire surface of the wiring layer 101 can be covered with the cap film 105 having high adhesion, the antioxidant effect can be further enhanced. If the almost entire surface of the wiring layer 101 can be covered with the cap film 105 as in the semiconductor device shown in FIG. 3, the step of forming the nitrogen-containing copper silicide film 106 shown in FIG. Also good.

(Modification of Example 1)
Next, with reference to FIGS. 2 and 4, a modification of the method for manufacturing the semiconductor device according to the first embodiment will be described. FIG. 4 is a process cross-sectional view illustrating the method of manufacturing the main part of the semiconductor device according to the variation of the first embodiment. According to the manufacturing process of the semiconductor device according to Example 1 described above, after forming the cap film 105 on the wiring layer 101 by the electroless plating method, the nitrogen-containing copper silicide film 106 is formed on the exposed wiring layer 101 surface. However, in the method of manufacturing the semiconductor device according to this modification, the order of forming these two films is changed.

First, as shown in FIGS. 2A and 2B, an interlayer insulating layer having a wiring layer, a plug, or the like formed thereon is stacked on a semiconductor substrate (not shown), and then predetermined by photolithography and RIE. A groove 107 for forming the wiring layer 101 is formed in the first insulating layer 100 which is an interlayer insulating layer. Furthermore, after sequentially forming a barrier film material and a wiring material mainly composed of copper on the first insulating layer 100 and in the groove 107, the wiring material and the barrier film material outside the groove 107 are sequentially polished and removed. A wiring layer 101 and a barrier film 102 are formed inside one insulating layer 100.

Next, as shown in FIG. 4A, a nitrogen-containing copper silicide film 106 is formed in a self-aligned manner on the surface of the wiring layer 101 exposed on the surface of the first insulating layer 100.

That is, in a low pressure chamber maintained in a high temperature atmosphere, a silane gas is exposed to the copper surface portion of the wiring layer 101 to form a copper silicide film, and further, ammonia is used on the surface of the wiring layer 101 using ammonia gas in a constant low pressure state. Plasma treatment is performed to form a nitrogen-containing copper silicide film 106. At this time, the surface of the wiring layer 101 can be covered with the conductive nitrogen-containing copper silicide film 114 by reducing the nitrogen contained in the copper silicide film to a certain concentration or less by ammonia plasma treatment. The nitrogen-containing copper silicide film 106 is easier to form uniformly on the copper surface than the cap film 105 formed by electroless plating, and is formed almost uniformly on the surface of the wiring layer 101. be able to.

Next, as shown in FIG. 4B, a cap film 105 containing cobalt is formed by electroless plating on the surface of the wiring layer 101 on which the nitrogen-containing copper silicide film 106 is formed.

The method for forming the cap film 105 is almost the same as the method for forming the cap film 105 shown in FIG. That is, the surface of the wiring layer 101 on which the nitrogen-containing copper silicide film 106 is formed is immersed in an aqueous palladium chloride solution so that the palladium plating layer serving as the catalytically active layer is self-aligned in the region where the copper component on the surface of the wiring layer 101 exists. Form. After forming the catalytic active layer, a cap film 105 containing a cobalt compound as a constituent component is formed on the catalytic active layer forming portion on the surface of the wiring layer 101 by an electroless plating method using a plating solution containing a cobalt sulfate aqueous solution or the like.

The cap film 105 formed by the electroless plating method according to this modification is formed only on the catalytically active layer formed only in the region where the copper component in the nitrogen-containing copper silicide film 106 on the surface of the wiring layer 101 exists. Therefore, it may be difficult to form on the surface of the wiring layer 101 as compared with the cap film 105 of the semiconductor device according to the first embodiment shown in FIG.

However, the wiring layer 101 according to this modification has a nitrogen-containing copper silicide film 106 formed on the entire surface, and a cap film 105 formed on at least a part of the nitrogen-containing copper silicide film 106. . For this reason, a laminated structure of the nitrogen-containing copper silicide film 106 and the cap film 105 is formed on a part of the surface of the wiring layer 101, and wiring with a single layer of the cap film 105 or the nitrogen-containing copper silicide film 106 as described above. Compared with the antioxidant effect on the surface of the layer 101, the antioxidant effect can be locally enhanced.

Next, after forming the nitrogen-containing copper silicide film 106 and the cap film 105, as shown in FIG. 4C, the upper interlayer insulating layer is formed on the first insulating layer 100 by using the CVD method or the like. A second insulating layer 103 is formed, and although not shown, a plug electrically connected to the wiring layer 101 is embedded in the second insulating layer 103.

At this time, when the plug embedding groove is formed in the second insulating layer 103 by RIE, the nitrogen-containing copper silicide film 106 exposed on the bottom surface of the groove may be peeled off by a CF-based etching gas used for this RIE. Is possible. Accordingly, since the nitrogen-containing copper silicide film 106 at the interface between the plug and the wiring layer 101 can be easily peeled off, the plug and the wiring layer 101 can be brought into contact with each other.

According to the semiconductor device according to this modification manufactured through the above steps, the wiring layer 101 has a good quality nitrogen-containing copper on the entire surface at the interface between the wiring layer 101 and the second insulating layer 103. Since the silicide film 106 is formed and the cap film 105 having a high EM resistance is formed on a part of the silicide film 106, oxidation of the surface of the wiring layer 101 can be more effectively prevented, and the copper component on the surface of the wiring layer 101 can be prevented. The diffusion to the second insulating layer 103 can be prevented, and the reliability of the semiconductor device can be improved.

Next, still another configuration example of the semiconductor device according to the present embodiment will be described with reference to FIG. FIG. 5 is a cross-sectional view showing still another configuration of the semiconductor device according to this example.

  The semiconductor device shown in FIG. 5A is formed on the surface of the cap film 105 and the wiring layer 101 formed on the first insulating layer 100 and the wiring layer 101 in order to more effectively prevent the oxidation of the wiring metal. A barrier insulating film 108 is formed so as to cover the nitrogen-containing copper silicide film 106. The barrier insulating film 108 is, for example, an insulating silicon carbide film or silicon nitride film formed by a CVD method or the like.

  According to this semiconductor device, at the interface between the wiring layer 101 and the second insulating layer 103, a barrier having an effect of preventing the wiring metal from being oxidized on the wiring layer 101 as well as the cap film 105 and the nitrogen-containing copper silicide film 106. Since the insulating film 108 is formed, the antioxidant effect on the surface of the wiring layer 101 can be further improved as compared with the above-described semiconductor device. At this time, in order to reduce the capacitance between the wirings as much as possible, the barrier insulating film 108 formed in a region other than the wiring layer 101 and the barrier film 102 may be removed by photolithography and RIE.

  In the semiconductor device in which the cap film 105 is formed on the wiring layer 101 shown in FIG. 3, the barrier insulating film may be formed so as to cover the cap film 105 on the wiring layer 101. In the semiconductor device in which the nitrogen-containing copper silicide film 106 is formed on the surface of the wiring layer 101 shown in the process cross-sectional view of FIG. 4 and the cap film 105 is further formed on the nitrogen-containing copper silicide film 106, the barrier insulating film May be formed so as to cover the nitrogen-containing copper silicide film 106 and the cap film 105.

  In the semiconductor device shown in FIG. 5B, the height of the cap film 105 formed on the wiring layer 101 is substantially equal to the height of the first insulating layer 100 or higher than the height of the first insulating layer 100. It has a low structure. As shown in FIG. 2B, the structure of this semiconductor device is such that, after a wiring layer 101 is formed on the first insulating layer 100, the upper part of the wiring layer 101 is etched away by RIE, and then the wiring is formed by electroless plating. It can be constructed by forming the cap film 105 on the layer 101 to the same height as the first insulating layer 100.

  According to this semiconductor device, not only the cap film 105 formed on the wiring layer 101 and the nitrogen-containing copper silicide film 106 formed on the surface of the wiring layer 101 can prevent the surface of the wiring layer 101 from being oxidized, The difference in the surface height of the cap film 105 formed on the wiring layer 101 having a different wiring density can be adjusted. In other words, the formation speed of the cap film 105 is relatively higher on the wiring layer 101 having a higher wiring density than on the wiring layer 101 having a lower wiring density, but the upper part of the wiring layer 101 is etched away before the formation of the cap film 105. As a result, the surface height of the cap film 105 can be made substantially equal to the surface height of the cap film 105 formed on the wiring layer 101 having a low wiring density.

  Further, a semiconductor device in which a cap film 105 is formed on the wiring layer 101 shown in FIG. 3 or a nitrogen-containing copper silicide film 106 is formed on the surface of the wiring layer 101 shown in the process sectional view of FIG. Even in the semiconductor device in which the cap film 105 is formed on the nitrogen-containing copper silicide film 106, the upper portion of the wiring layer 101 is removed by etching before the cap film 105 or the nitrogen-containing copper silicide film 106 is formed on the wiring layer. Also good.

  In the semiconductor device according to the above-described embodiment and the modified example of the embodiment, the cap film 105 is not formed on the barrier film 102 formed around the surface of the wiring layer 101. However, by the electroless plating method, The cap film 105 may be formed up to the barrier film 102 to prevent the barrier film 102 from being oxidized.

The configuration of the semiconductor device according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing the main parts of the semiconductor device according to Example 2 of the present invention. The semiconductor device according to this example relates to a semiconductor device provided with a fuse after fusing.

In the semiconductor device according to this embodiment, an interlayer insulating layer such as a silicon oxide film is laminated on a semiconductor substrate (not shown), and a wiring material such as a wiring layer or a plug is formed in each interlayer insulating layer. Thus, a wiring circuit having a multilayer structure is constructed.

As shown in FIG. 6, a predetermined insulating layer 109 (interlayer insulating layer) is blown by irradiating a laser beam or the like in addition to the wiring material 110 such as a wiring layer, and the fusing of the copper fuse 111. An opening 112 formed along with this is formed. On the insulating layer 109, an upper insulating layer 109 including a fusing opening 113 for fusing the copper fuse 111 and a wiring material 110 such as a plug is formed. Although illustration is omitted, barrier films are formed on the side and bottom surfaces of the wiring material 110.

Further, the melted cross section of the copper fuse 111 is exposed on the inner wall of the opening 112, and the exposed surface of the copper fuse 111 (melted cross section) prevents oxidation of the copper fuse 111 surface and suppresses corrosion. A nitrogen-containing copper silicide film 114 is selectively formed.

The nitrogen-containing copper silicide film 114 having an antioxidant function is a thin film similar to the nitrogen-containing copper silicide film 106 in the first embodiment, and is formed on the surface of the copper fuse 111 by the same method as in the first embodiment. That is, the nitrogen-containing copper silicide film 114 is exposed to high temperature and low pressure after the fuse 111 is blown to expose the copper surface of the fuse 111 to form a copper silicide film, and remains on the surface of the fuse 111 in a constant low pressure state. By performing the ammonia plasma treatment, it is formed on the exposed surface of the fuse 111 in a self-aligning manner. At this time, the surface of the copper fuse 111 can be covered with the insulating nitrogen-containing copper silicide film 114 by setting the nitrogen contained in the copper silicide film to a certain concentration or more by ammonia plasma treatment. The possibility of electrical shorts can be reduced.

According to the semiconductor device of the present embodiment, the surface of the fuse 111 exposed by fusing is protected by the nitrogen-containing copper silicide film 114, and the oxidation and corrosion of the surface of the fuse 111 due to exposure to oxidizing gas or immersion of moisture are suppressed. The reliability of the semiconductor device can be ensured.

Further, since this nitrogen-containing copper silicide film 114 is formed only on the exposed surface of the copper fuse 111, an antioxidant film such as a silicon carbide film or a silicon nitride film is formed on the entire surface including the exposed surface of the fuse 111 by a CVD method or the like. Compared to the case, the anti-oxidation film is not formed to an extra portion, and the influence on the characteristics of the semiconductor device can be reduced. Furthermore, since the adhesion to the surface of the copper fuse 111 is higher than that of an antioxidant film such as a silicon carbide film or a silicon nitride film, oxidation of the exposed surface of the fuse 111 can be more effectively prevented.

The configuration of the semiconductor device according to the third embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view showing the main parts of a semiconductor device according to Example 3 of the invention. The semiconductor device according to this example relates to a semiconductor device in which the above-mentioned nitrogen-containing copper silicide film is formed on the exposed surface of a conductor pad to which a bonding wire serving as a signal input / output unit is connected.

As shown in FIG. 7, the semiconductor device according to this embodiment has an insulating layer 115 (interlayer insulating layer) such as a silicon oxide film stacked on a semiconductor substrate (not shown), and in each interlayer insulating layer 115. It has a multilayer wiring structure in which a wiring circuit made of a wiring material 116 such as a wiring layer and a plug is formed. Although illustration is omitted, barrier films are formed on the side and bottom surfaces of the wiring material 116.

A conductor pad 117 is formed on the uppermost interlayer insulating layer 115, and the wiring circuit is electrically connected to the conductor pad 117. In this embodiment, the wiring material 116 such as a wiring layer and the conductor pad 117 are made of copper or a copper alloy, and a barrier film is also formed on the side surface and the bottom surface of the conductor pad 117.

On the uppermost interlayer insulating layer 115, a passivation film 118 made of, for example, a silicon oxide film, a silicon nitride film, a polyimide resin, or the like is used to protect a wiring circuit or the like inside the semiconductor device from external stress or the like. Is formed.

The conductor pad 117 is formed so that the surface is exposed from the opening formed in the interlayer insulating layer 115 and the passivation film 118, and inputs / outputs signals to / from the semiconductor device outside part of the exposed surface of the conductor pad 117. A bonding wire 119 serving as an external terminal is formed. By electrically connecting the bonding wire 119 to an external device, a signal is input from the external device to the inside of the device, or a signal is sent from the inside of the semiconductor device to the external device. Is output.

An insulating nitrogen-containing copper silicide film 120 is selectively formed on the exposed surface of the conductive pad 117 excluding the bonding wire 119 formation portion in order to prevent the surface of the conductive pad 117 from being oxidized and suppress corrosion. The nitrogen-containing copper silicide film 120 having an anti-oxidation function is a thin film similar to the nitrogen-containing copper silicide film 106 in the above-described first embodiment, and is formed on the surface of the conductor pad 117 by substantially the same method as in the first embodiment. . That is, after the wire 119 is bonded to the conductor pad 117, the nitrogen-containing copper silicide film 120 is exposed to a silane gas on the surface of the conductor pad 117 exposed under high temperature and low pressure to form a copper silicide film. By subjecting the exposed conductor pad 117 surface to ammonia plasma treatment, the exposed conductor pad 117 surface is formed in a self-aligned manner.

According to the semiconductor device of this embodiment, the exposed surface of the conductor pad 117 is protected by the nitrogen-containing copper silicide film 120, whereby the oxidation resistance and corrosion resistance of the surface of the conductor pad 117 can be improved. Reliability can be improved.

As a means for preventing oxidation on the surface of the conductor pad 117, a conventional technique is known in which a bonding wire 119 is formed on the conductor pad 117 and then an aluminum layer is formed on the conductor pad 117 as an antioxidant layer. However, according to this conventional technique, a photolithography process and an RIE process are further required after the aluminum layer forming process by a sputtering method or the like, so that there is a problem that the manufacturing process increases and the manufacturing cost becomes very high. is there. Another problem is that aluminum itself is more expensive than copper or the like.

On the other hand, in the manufacturing process of the semiconductor device according to the present embodiment, the nitrogen-containing copper silicide film 120 as the oxidation preventing layer is formed in a self-aligned manner only on the exposed surface of the conductor pad 117. In contrast, the photolithography process and the RIE process are not required, and expensive aluminum is not used, so that the manufacturing process can be simplified and the manufacturing cost can be reduced.

Further, in the semiconductor device according to the present embodiment, as in the first embodiment, a cap film containing cobalt is self-aligned on the nitrogen-containing copper silicide film 120 formed on the surface of the conductor pad 117 by an electroless plating method. It may be formed to improve the antioxidant effect on the surface of the conductor pad 117. Further, as in Example 1, after forming a cap film containing cobalt on the conductor pad 117 by electroless plating in a self-aligned manner, a nitrogen-containing copper silicide is formed on the surface of the conductor pad 117 not covered with the cap film. The film 120 may be formed to prevent the surface of the conductor pad 117 from being oxidized.

Sectional drawing which shows the structure of the principal part of the semiconductor device which concerns on Example 1 of this invention. Process sectional drawing which shows the manufacturing method of the principal part of the semiconductor device which concerns on Example 1 of this invention. Sectional drawing which shows the other structure of the principal part of the semiconductor device which concerns on Example 1 of this invention. Process sectional drawing which shows the manufacturing method of the principal part of the semiconductor device which concerns on the modification of Example 1 of this invention. Sectional drawing which shows the further another structure of the principal part of the semiconductor device which concerns on Example 1 of this invention. Sectional drawing which shows the structure of the principal part of the semiconductor device which concerns on Example 2 of this invention. Sectional drawing which shows the structure of the principal part of the semiconductor device which concerns on Example 3 of this invention.

Explanation of symbols

100: first insulating layer
101: Wiring layer
102: Barrier film 103: Second insulating layer 104: Plug
105: Cap membrane
106, 114, 120: Nitrogen-containing copper silicide film 107: Groove 108: Barrier insulating film 109, 115: Insulating layer (interlayer insulating layer)
110, 116: Wiring material
111: Copper fuse
112: opening
113: Fusing opening 117: Conductor pad
118: Passivation film
119: Bonding wire

Claims (5)

Forming a first insulating layer on the semiconductor substrate;
Forming a groove in the first insulating layer, and forming a wiring layer containing copper on the surface in the groove;
Forming a cap film containing cobalt on the wiring layer surface;
Forming a nitrogen-containing copper silicide film on the wiring layer surface excluding the cap film forming portion;
A method for manufacturing a semiconductor device, comprising: Forming a first insulating layer on the semiconductor substrate;
Forming a groove in the first insulating layer, and forming a wiring layer containing copper on the surface in the groove;
Forming a cap film containing cobalt on the wiring layer surface;
A step of performing an activation process on the surface of the wiring layer including at least the cap film non-forming portion, and forming the cap film containing cobalt again on the wiring layer surface subjected to the activation process;
A method for manufacturing a semiconductor device, comprising: Forming a first insulating layer on the semiconductor substrate;
Forming a groove in the first insulating layer, and forming a wiring layer containing copper on the surface in the groove;
Forming a nitrogen-containing copper silicide film on the wiring layer surface;
Forming a cap film containing cobalt on the surface of the nitrogen-containing copper silicide film;
A method for manufacturing a semiconductor device, comprising: An interlayer insulating layer formed on the semiconductor substrate;
A wiring layer containing copper on the surface formed in the interlayer insulating layer;
A cap film containing cobalt formed on the wiring layer surface;
A nitrogen-containing copper silicide film formed on the surface of the wiring layer excluding the cap film forming portion;
A semiconductor device comprising: An opening formed in an insulating layer on a semiconductor substrate;
A copper-containing member whose surface is exposed in the opening;
A nitrogen-containing copper silicide film formed on the exposed surface of the copper-containing member;
A semiconductor device comprising:

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