JP2007242947A - Barrier film for semiconductor wiring, copper wiring for semiconductor, manufacturing method of this wiring, and sputtering target for forming semiconductor barrier film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a barrier film for a highly dense copper wiring semiconductor which can obtain a sufficient barrier effect with a film thickness enough to prevent film peeling and a fine wiring pitch in suppressing diffusion of a copper in the highly dense copper wiring semiconductor, and has no variation in barrier characteristics even if a temperature rises due to heat treatment, and to provide a sputtering target for forming the barrier film. <P>SOLUTION: The barrier film for a highly dense copper wiring semiconductor consists of an Ni-Cr-based alloy film containing Cr: 5-30 wt.%, Ti and/or Zr: 1-10 wt.%, wherein the residue consists of inevitable impurities and Ni, the film thickness is 3-150 nm, and film thickness uniformity is not more than 10% at 1 σ. The sputtering target for forming the barrier film is an Ni-Cr-based alloy containing Cr: 5-30 wt.%, Ti and/or Zr: 1-10 wt.%, wherein the residue consists of inevitable impurities and Ni, and a relative permeability in an in-plane direction of a sputtering face is not more than 100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a barrier film for semiconductor wiring, a copper wiring for semiconductor, a manufacturing method of the wiring, and a sputtering target for forming a semiconductor barrier film that can effectively suppress copper diffusion.

Conventionally, as a fine wiring material of a high-density integrated circuit formed on a semiconductor wafer, copper capable of increasing the speed has been used instead of an aluminum alloy. Copper has a characteristic that the specific resistance is as low as 1.8 μWcm and the electromigration resistance is one digit higher than that of the aluminum alloy system. By the way, many trenches and vias for connecting elements are formed in a semiconductor device, and these are formed by forming an opening in an interlayer insulating layer and embedding a conductive material therein.
In recent years, trenches and via holes have been formed by forming a trench in the interlayer insulating layer and filling the trench with copper to form a trench wiring, or by embedding the trench and the opening provided at the bottom of the trench with copper. Wiring formation by a dual damascene method in which the two are integrally formed is being put into practical use. Inside an integrated circuit, metal wiring is stretched over several layers to transmit signals. However, as the distance between wirings becomes shorter as the density increases, the copper formed in the trenches and vias becomes smaller. The problem of easy diffusion (migration) and short-circuiting of circuit wiring has occurred.

In order to suppress such diffusion of Cu, a barrier layer for preventing diffusion of Cu is previously formed under the trench or via, and a Cu seed layer and a Cu thick plating layer are formed thereon. It has been proposed.
A typical example is a Ni-Cr alloy barrier layer formed (see Patent Document 1). However, if there is a temperature rise of about 200 to 300 ° C., diffusion of Cu is still recognized. Further, it has been found that when the wiring width becomes narrow, the conventional barrier layer cannot prevent copper diffusion and is not necessarily effective.

As a means for preventing this, it is conceivable to improve the barrier characteristics by increasing the thickness of the conventional barrier layer. However, when the thickness is increased beyond a certain value, there is a problem that the film is peeled off. Therefore, this was not a fundamental solution.
There is an application example of polyimide to a flexible circuit board that is close to this technology, coating a barrier metal made of at least one metal selected from Ni, Cr, Co, and Mo, and fluidizing by heating a thermoplastic resin There is also a proposal to increase the bonding force between the thermoplastic polyimide and the barrier metal (see Patent Document 2).
However, in this case, the problem remains because it does not solve the fundamental barrier metal diffusion.
In view of the above, the present inventors have proposed the addition of Cr based on Co (Patent Document 3). Although this material is excellent in characteristics, there is a problem that the price of Co is two to three times that of Ni, leading to an increase in cost.
JP 2002-252257 A JP 2002-280684 A Japanese Patent Application No. 2004-2322872

    Due to the above-mentioned problems of the prior art, when suppressing the diffusion of copper formed by burying trenches and vias, a sufficient barrier effect can be obtained with a thin film thickness that does not cause film peeling and a narrow wiring width. It is another object of the present invention to obtain a barrier film for forming a semiconductor circuit and a sputtering target for forming a barrier film that do not change in barrier characteristics even when the temperature rises due to heat treatment or the like.

As a result of diligent research, the present inventors have used an alloy having effective barrier properties, made the barrier film as thin as possible to prevent peeling, and improve the uniformity of the film formed, The knowledge that said subject can be solved was acquired.
The present invention is based on this finding,
1. Cr: 5 to 30 wt%, Ti and / or Zr: 1 to 10 wt%, the balance is made of a Ni—Cr based alloy film made of inevitable impurities and Ni, the film thickness is 3 to 150 nm, and the film thickness uniformity is 1. Barrier film for semiconductor wiring, wherein 1σ is 10% or less Provided on a semiconductor substrate is a barrier film made of a Ni—Cr alloy having a film thickness of 3 to 150 nm and a film thickness uniformity of 10% or less at 1σ, and a copper coating layer formed on the barrier film. 2. Copper wiring for semiconductor, characterized in that The barrier film made of a Ni—Cr alloy is a Ni—Cr alloy film containing 5 to 30 wt% of Cr, Ti and / or Zr: 1 to 10 wt%, and the balance being inevitable impurities and Ni. 3. The copper wiring for semiconductors according to the above item 2, The copper coating layer formed on the barrier film is an electroless copper plating layer or an electroless copper plating seed layer and an electrolytic copper plating layer formed thereon. 4. Copper wiring 4. The copper for semiconductor according to the above 2 or 3, wherein the copper coating layer formed on the barrier film is a copper sputtered film or a seed layer made of a copper sputtered film and an electro copper plating layer formed thereon. Wiring, provide.

The present invention also provides: A barrier film made of a Ni-Cr alloy is formed on a semiconductor substrate by sputtering, and an electroless copper plating layer or an electroless copper plating seed layer and a copper coating layer by electrolytic copper plating are further formed thereon. 6. Manufacturing method of semiconductor wiring A barrier film made of a Ni—Cr alloy is formed on a semiconductor substrate by sputtering, and a copper seed layer made of a sputtered copper coating layer or a sputtered film and a copper coating layer formed by electrolytic copper plating are formed on the barrier film. 7. Manufacturing method of semiconductor wiring 8. The method for producing a copper wiring for a semiconductor according to 6 or 7 above, wherein the barrier film made of a Ni—Cr alloy has a film thickness of 3 to 150 nm and a film thickness uniformity of 1σ of 10% or less. The barrier film made of a Ni—Cr alloy is a Ni—Cr alloy film containing 5 to 30 wt% of Cr, Ti and / or Zr: 1 to 10 wt%, and the balance being inevitable impurities and Ni. 9. The method for producing a copper wiring for a semiconductor according to any one of 6 to 8 above. Ni—Cr-based alloy containing 5-30 wt% Cr, Ti and / or Zr: 1-10 wt%, the balance being inevitable impurities and Ni, and having a relative permeability of 100 in the in-plane direction of the sputtering surface A sputtering target for forming a semiconductor barrier film is provided.

  The barrier film for semiconductor copper wiring of the present invention has a thin film thickness that does not cause film peeling, and can obtain a sufficient barrier effect even with a narrow wiring width. It has an excellent feature that there is no change in characteristics. The present invention has significant characteristics that effectively suppress copper diffusion in semiconductor copper wiring materials.

The barrier film for semiconductor copper wiring material of the present invention is a Ni—Cr alloy film containing Cr: 5 to 30 wt%, Ti and / or Zr: 1 to 10 wt%, and the balance being inevitable impurities and Ni.
In the film composition, when Cr is less than 5 wt%, the barrier property is not sufficient, and there is no advantage over the conventional barrier film. On the other hand, if the Cr content exceeds 30 wt%, this barrier film hinders polishing during CMP (Chemical Mechanical Polishing), so that it takes too much time for removal and is not suitable for practical use. Therefore, the Cr range is set.
Further, the addition of Ti and / or Zr is effective for significantly improving the barrier characteristics and increasing the durability of the film and ensuring the uniformity of the film, as shown in the examples described later. The addition amount is preferably 1 to 10 wt%. When the content of Ti and / or Zr is less than 1 wt%, the effect of improving the durability of the film is small, and improvement in film uniformity cannot be expected. On the other hand, if the content of Ti and / or Zr exceeds 10 wt%, film peeling is likely to occur, so the above range is set.

The thickness of the barrier film for semiconductor copper wiring material of the present invention is 3 to 150 nm. When the film thickness is less than 3 nm: it does not have sufficient barrier properties. Moreover, since it will become easy to produce film peeling when a film thickness exceeds 150 nm, it is set as said range.
The film thickness of the barrier film for semiconductor copper wiring material of the present invention is 10% or less with a film thickness uniformity of 1σ. Maintaining this film uniformity at an appropriate value is extremely important in forming a wiring having a uniform width. If the film thickness uniformity (1σ) exceeds 10%, the copper film formed on the barrier film becomes non-uniform, which causes a problem in that the transmission characteristics of the semiconductor are hindered. Therefore, the film thickness uniformity (1σ) is set to 10% or less.

As for the sputtering target for forming a barrier film of the present invention, a Ni—Cr based alloy target containing 5 to 30 wt% of Cr, Ti and / or Zr: 1 to 10 wt%, and the balance of inevitable impurities and Ni is used. The composition of the Ni—Cr alloy target of the present invention is directly reflected in the composition of the barrier film. That is, when the target composition Cr is less than 5 wt%, a Ni—Cr alloy film of 5 wt% Cr or more cannot be formed.
On the other hand, if Cr exceeds 30 wt%, a film of Ni alloy with Cr of 30% or less cannot be formed.
Similarly, when the content of Ti and / or Zr is less than 1 wt%, a Ni—Cr alloy film with Ti and / or Zr of 1 wt% or more cannot be formed. Further, when the content of Ti and / or Zr exceeds 10 wt%, a Ni—Cr alloy film having Ti and / or Zr of 10 wt% or less cannot be formed. Therefore, the composition of the Ni—Cr-based alloy target is within the above range.
Further, the relative permeability in the in-plane direction of the sputtering surface of the sputtering target for forming a barrier film of the present invention is set to 100 or less. This is because when the relative magnetic permeability exceeds 100, the film thickness uniformity of the sputtered film exceeds 10% at 1σ.

The Ni—Cr-based alloy target of the present invention preferably has an average crystal grain size of 500 μm or less, particularly 100 μm or less. This is because when the average crystal grain size exceeds 500 μm, the amount of particles generated increases, film defects called pinholes increase, and the product yield decreases.
Further, the Ni—Cr alloy target of the present invention desirably has an average crystal grain size variation within 30% within the target. This is because if the variation in average particle diameter exceeds 30%, the film thickness uniformity of the sputtered film may exceed 10% at 1σ.

When manufacturing the target of the present invention, it is desirable to process the target plate by a combination of hot forging at 700 to 1280 ° C. and rolling.
Further, after the hot forging / rolling, heat treatment at a holding temperature of 300 to 950 ° C. may be performed in the air, in a vacuum, or in an inert gas atmosphere. The target thus obtained has an average roughness (Ra) of a portion to be sputtered of 0.01 to 5 μm.
Further, the average roughness (Ra) of the surface of the non-sputtered surface such as the side surface of the target or the backing fret, that is, the portion to which the sputtered material adheres is reduced by sandblasting, etching, or formation of a sprayed coating layer. It is desirable to roughen the surface to 50 μm to prevent the attached film from peeling again. This is because the substance that re-peels and floats in the sputtering atmosphere causes generation of particles on the substrate.

The target of the present invention can be bonded to the backing plate of Al alloy, Cu, Cu alloy, Ti, Ti alloy or the like by brazing or metal bonding of the diffusion bonding method so that it can withstand high power sputtering, or the backing plate portion can be The same material as the target material is used for integral molding.
Further, as impurities contained in the target, the concentrations of Na and K are each 5 ppm or less (hereinafter, ppm indicates wtppm), the concentrations of U and Th are each 0.05 ppm or less, and other than the main elements and additive elements It is desirable that the total amount of metal elements is 0.5 wt% or less and the oxygen concentration is 0.5% or less.

In the production of the semiconductor wiring of the present invention, a barrier film made of a Ni—Cr alloy is formed on a semiconductor substrate by sputtering, and an electroless plating layer or an electroless plating seed layer and electrolytic copper plating are further formed thereon. A copper coating layer can be formed to form a high-density semiconductor wiring. The barrier film of the present invention can effectively suppress the diffusion of copper into the semiconductor substrate even in such a highly integrated wiring film.
After the barrier film made of the Ni—Cr alloy is formed, a copper seed layer made of a sputtered copper coating layer or a sputtered film and a copper coating layer by electrolytic copper plating can be further formed thereon. This can be appropriately selected according to the manufacturing process.
In the case of forming a barrier film made of the Ni—Cr alloy, it is necessary that the film thickness is 3 to 150 nm and the film thickness uniformity is 10% or less at 1σ. Further, this barrier film is preferably a Ni—Cr-based alloy film containing 5 to 30 wt% of Cr, Ti and / or Zr: 1 to 10 wt%, and the balance being inevitable impurities and Ni.
The above-described Ni—Cr alloy barrier film is formed by sputtering, but it is desirable to use a sputtering target for forming a semiconductor barrier film having a relative permeability of 100 or less in the in-plane direction of the sputtering surface.

  Next, the present invention will be described based on examples. The following examples are for ease of understanding, and the present invention is not limited by these examples. Modifications and other embodiments based on the technical idea of the present invention are naturally included in the present invention. That is, it should be easily understood that the following examples show only some of the preferred examples, and the present invention is not limited to the following examples.

(Example 1-9)
In order to manufacture the target shown in Table 1, the composition of Ni, Cr, Ti and / or Zr was melted and cast to prepare various Ni—Cr ingots. This was hot forged and hot rolled at 1100 ° C., and after cooling, heat-treated at 500 ° C. for 2 hours to be processed into a target. The crystal grain size of this target was in the range of 80 to 250 μm depending on the target. This was further finished to a surface roughness Ra of 0.14 μm.
The Cr concentration in the target was in the range of 10.2 to 29.5 wt%, the Ti concentration was in the range of 1.5 to 9.5 wt%, and the Zr concentration was 5.3 wt%. In addition, although there are few examples which added Zr in the Example, since Zr is a material substantially the same effect as Ti and becomes complicated, it was omitted.
In addition, the impurity components were Na: 0.2 ppm, K: 0.1 wtppm, U: 0.02 ppm, Th: 0.03 ppm, the total of metal components was 250 to 470 ppm, and oxygen was 10 to 20 ppm.
This target was bonded to the backing plate with indium, and the side surface of the target and the backing plate near the target were roughened to Ra = 7.5 μm by sand blasting.

A barrier layer having a thickness of 140 nm was formed on a SiO ₂ substrate using an alloy composition and relative permeability target within the scope of the present invention shown in Table 1.
Table 1 shows the results of measuring the composition (wt%) of each additive component of the barrier layer, the thickness of the barrier layer (nm), and the thickness of the barrier layer at 49 points and examining the uniformity (%) of the thickness. Shown in The film compositions (wt%), film thickness (nm), and film thickness uniformity (%) of the barrier films of Examples 1 to 9 all fall within the scope of the present invention.
Although a slight difference is observed between the target composition and the film composition, the amount is slight and it can be seen that the target composition is reflected in the film.
Further, a Cu seed layer having a thickness of 20 nm was formed on the barrier layer by sputtering, and then a 200 nm Cu layer was formed by electroplating.

About this Cu / Ni-Cr-based alloy film, a profile was formed in the depth direction by AES (Auger Electron Spectroscopy) for the as-deposited sample and the sample that was heat-treated in vacuum at 300 ° C for 2 hours. Then, the diffusion of Cu into the barrier layer was evaluated.
1 and 2 show the results of AES. In the case where the Ni—Cr alloy in this example is used as a barrier film, the Cu profile shows the same profile as that without heat treatment even when heat-treated at 300 ° C., and diffusion into the barrier layer Was not recognized. When compared with Comparative Example 1 shown below, it was confirmed that the barrier properties were significantly improved by the addition of Ti and / or Zr. The results are also shown in Table 1.

(Comparative Example 1)
A material having a composition of Ni-19.80 wt% Cr, which is a conventional barrier material, was melted and cast to prepare a Ni-Cr ingot. This was hot forged and hot rolled at 1100 ° C., and after cooling, heat-treated at 500 ° C. for 2 hours to be processed into a target.
The crystal grain size of this target was 300 μm, and the surface roughness was finished to 0.15 μm with Ra. Cr concentration in the target is 19.7 wt%, impurity components are Na: 0.1 ppm, K: 0.3 ppm, U: 0.02 ppm, Th: 0.04 ppm, total of impurity metal components is 510 ppm, oxygen is 10 ppm Met.

The target was bonded to the backing plate with indium, and the side surface of the target and the backing plate portion in the vicinity of the target were roughened by sand blasting at Ra = 7.0 μm. The relative permeability in the in-plane direction of the target was 30.
Using this target, a barrier layer having a thickness of 140 nm was formed on the SiO ₂ substrate. When the composition of each additive component in the barrier layer was analyzed, Cr was 19.7 wt%, and the composition was slightly less Cr. When the film thickness of this barrier layer was measured at 49 points and the film thickness uniformity was examined, it was 6.5% at 1σ. The results are shown in Table 1.

  A Cu film having a thickness of 200 nm was formed on the barrier layer by sputtering. About this Cu / Ni-Cr film, about the sample as it was formed and the sample which performed heat processing for 300 ° C x 2 hours in a vacuum, take a profile in the depth direction by AES (Auger electron spectroscopy), The diffusion of Cu into the barrier layer was evaluated. FIG. 3 shows the results of AES. The Cu profile that was heat-treated at 300 ° C. entered the barrier layer more than the one that was not heat-treated. That is, it turned out that the function as a barrier layer is low. The results are similarly shown in Table 1.

(Comparative Example 2)
A target shown in Table 1 was manufactured by the same operation as in Comparative Example 1, and a Ni—Cr—Ti alloy barrier layer having a thickness of 2.5 nm was formed on the SiO ₂ substrate using this target. The relative permeability in the in-plane direction of the target was 35. Table 1 shows the results of measuring the uniformity (%) of the film thickness by measuring the composition (wt%) of each additive component of the barrier layer, the thickness of the barrier layer (nm), and the thickness of the barrier layer at 49 points. Show.
Although the film thickness of the barrier film of Comparative Example 2 is as thin as 2.5 nm, the target composition of the present invention is the same as the component composition, but the film thickness is different. Further, a Cu seed layer was formed to 20 nm on the barrier layer, and then a 200 nm Cu layer was formed by electroplating.
Regarding the Ni—Cr—Ti alloy barrier film, a profile was taken in the depth direction by AES (Auger Electron Spectroscopy) for the as-deposited sample and the sample that was heat-treated in vacuum at 300 ° C. for 2 hours, The diffusion of Cu into the barrier layer was evaluated.
It was found that the Cu profile of the material heat-treated at 300 ° C. entered the barrier layer than that not heat-treated, and the function as the barrier layer was low. The results are also shown in Table 1.

(Comparative Example 3)
A target shown in Table 1 was manufactured in the same manner as in Comparative Example 1, and a 10 nm thick Ni—Cr—Ti alloy barrier layer shown in Table 1 was formed on the SiO ₂ substrate using this target. The relative permeability in the in-plane direction of the target was 25. Table 1 shows the results of measuring the composition (wt%) of each additive component of the barrier layer, the thickness of the barrier layer (nm), and the thickness of the barrier layer at 49 points and examining the uniformity of the thickness (%). Show.
In the barrier film of Comparative Example 3, Ti is excessively added at 12.0. Further, a Cu seed layer having a thickness of 20 nm was formed on the barrier layer, and then a 200 μm Cu layer was formed by electroplating. For the Ni—Cr—Ti alloy barrier film, a profile was taken in the depth direction by AES (Auger Electron Spectroscopy) for the as-deposited sample and the sample that was heat-treated at 300 ° C. for 2 hours in vacuum. The diffusion of Cu into the barrier layer was evaluated.
It was found that the Cu profile of the sample heat-treated at 300 ° C. entered the barrier layer more than that not heat-treated, and the function as the barrier layer was low. From the above, it was found that excessive addition of Ti in the barrier layer is not appropriate. The results are also shown in Table 1.

(Comparative Example 4)
A target shown in Table 1 was manufactured in the same manner as in Comparative Example 1, and a 10 nm thick Ni—Cr—Ti alloy barrier layer shown in Table 1 was formed on the SiO ₂ substrate using this target. The relative permeability in the in-plane direction of the target was 60. Table 1 shows the results of measuring the composition (wt%) of each additive component of the barrier layer, the thickness of the barrier layer (nm), and the thickness of the barrier layer at 49 points and examining the uniformity of the thickness (%). Show.
The barrier film of Comparative Example 4 has a Ti content of 0.9 and the added amount does not meet the requirements of the present invention. Further, a Cu seed layer was formed to 20 nm on the barrier layer, and then a 200 nm Cu layer was formed by electroplating. For the Ni—Cr—Ti alloy barrier film, a profile was taken in the depth direction by AES (Auger Electron Spectroscopy) for the as-deposited sample and the sample that was heat-treated at 300 ° C. for 2 hours in vacuum. The diffusion of Cu into the barrier layer was evaluated. It was found that the Cu profile of the material heat-treated at 300 ° C. entered the barrier layer more than that not heat-treated, and the function as the barrier layer was low.
These results are similarly shown in Table 1. In Comparative Example 5, the film thickness uniformity was as bad as 15.3%, and the barrier effect was reduced. Therefore, it was found that the durability is inferior when there is not a sufficient amount of Ti in the barrier layer.

(Comparative Example 5)
A target shown in Table 1 was manufactured in the same manner as in Comparative Example 1, and a 10 nm thick Ni—Cr—Ti alloy barrier layer shown in Table 1 was formed on the SiO ₂ substrate using this target. The relative permeability in the in-plane direction of the target was 30. Table 1 shows the results of measuring the composition (wt%) of each additive component of the barrier layer, the thickness of the barrier layer (nm), and the thickness of the barrier layer at 49 points and examining the uniformity of the thickness (%). Show.
The barrier film of Comparative Example 5 has a Cr content of 33.2 wt% and an added amount exceeding the specified amount of the present invention. Further, a Cu seed layer was formed to 20 nm on the barrier layer, and then a 200 nm Cu layer was formed by electroplating. Even when the heat treatment was performed at 300 ° C., the Cu profile showed the same profile as that without heat treatment, and no diffusion into the barrier layer was observed, confirming improvement in barrier properties. However, polishing by CMP takes too much time, and the Cu portion is excessively etched. From the above, it was found that excessive addition of Cr in the barrier layer is not appropriate. The results are also shown in Table 1.

(Comparative Example 6)
A target shown in Table 1 was manufactured by the same operation as in Comparative Example 1, and a 10 nm thick Ni—Cr—Ti alloy barrier layer shown in Table 1 was formed on the SiO ₂ substrate using this target. The relative permeability in the in-plane direction of the target was 30.
Table 1 shows the results of measuring the composition (wt%) of each additive component of the barrier layer, the thickness of the barrier layer (nm), and the thickness of the barrier layer at 49 points and examining the uniformity of the thickness (%). Show.
The barrier film of Comparative Example 6 has a Cr content of 9.2 wt% and does not reach the specified amount of the present invention. Further, a Cu seed layer was formed to 20 nm on the barrier layer, and then a 200 nm Cu layer was formed by electroplating.
For the Ni—Cr—Ti alloy barrier film, a profile was taken in the depth direction by AES (Auger Electron Spectroscopy) for the as-deposited sample and the sample that was heat-treated at 300 ° C. for 2 hours in vacuum. The diffusion of Cu into the barrier layer was evaluated. The Cu profile that was heat-treated at 300 ° C. entered the barrier layer more than the one that was not heat-treated. That is, it turned out that the function as a barrier layer is low. These results are similarly shown in Table 1.
In Comparative Example 6, the barrier effect was lowered and the durability was poor. Therefore, it was found that the durability is poor when there is not a sufficient amount of Cr in the barrier layer.

(Comparative Example 7)
It melt | dissolved by the same operation as the comparative example 1, and hot forged and rolled at 1100 degreeC, and produced the target shown in Table 1. Using this target having a relative magnetic permeability of 120 in the in-plane direction, a 10 nm thick Ni—Cr—Ti alloy barrier layer shown in Table 1 was formed on a SiO ₂ substrate.
Table 1 shows the results of measuring the composition (wt%) of each additive component of the barrier layer, the thickness of the barrier layer (nm), and the thickness of the barrier layer at 49 points and examining the uniformity of the thickness (%). Show.
The relative permeability of the target of Comparative Example 7 is 120, which does not reach the definition of the present invention. Further, a Cu seed layer was formed to 20 nm on the barrier layer, and then a 200 nm Cu layer was formed by electroplating. The Ni-Cr-Ti alloy barrier film was profiled in the depth direction by AES (Auger Electron Spectroscopy) for the as-deposited sample and the sample that was heat-treated in vacuum at 300 ° C for 2 hours. The diffusion of Cu into the barrier layer was evaluated.
Although Cu was heat-treated at 300 ° C., the Cu profile entered the barrier layer more than the one not heat-treated. That is, it turned out that the function as a barrier layer is low.
These results are similarly shown in Table 1. In Comparative Example 7, the uniformity of the film thickness was as bad as 13.1%, and the barrier effect was low. Therefore, it was found that when the relative permeability is too high, the uniformity of the film thickness is poor and the durability is inferior.

(Comparative Example 8)
It melt | dissolved by the same operation as the comparative example 1, only hot forging was performed at 1100 degreeC, the target shown in Table 1 was manufactured, and the relative permeability of the in-plane direction of the target was 150 using this target A 10 nm-thick Ni—Cr—Ti alloy barrier layer shown in Table 1 was formed on the SiO ₂ substrate.
The relative magnetic permeability of the target of Comparative Example 8 was 150, which was higher than that of Comparative Example 7 above. An attempt was made to form a film by sputtering, but film formation was impossible. Therefore, it was found that when the relative magnetic permeability is too high, even film formation is impossible and not appropriate. The results are also shown in Table 1.

From the above, it is important that the Ni—Cr alloy film and the target of the present invention contain an appropriate amount of Cr, Ti and / or Zr. In particular, the addition of Ti and / or Zr is effective in remarkably improving the barrier properties, increasing the durability of the film, and ensuring the uniformity of the film.
In addition, the barrier film thickness for the high-density copper wiring semiconductor of the present invention is required to be 3 to 150 nm. When the film thickness is less than 3 nm, it does not have sufficient barrier properties. Further, if the film thickness exceeds 150 nm, film peeling is likely to occur, and it does not make sense as a trench / via barrier film.
Furthermore, the barrier film thickness for high-density copper wiring semiconductors of the present invention needs to have a film thickness uniformity of 10% or less at 1σ. Maintaining this film uniformity at an appropriate value is extremely important in forming a wiring having a uniform width.
In the sputtering target for forming a barrier film of the present invention, the relative permeability in the in-plane direction of the sputtering surface needs to be 100 or less. When the relative magnetic permeability exceeds 100, the film thickness uniformity of the sputtered film exceeds 10% at 1σ, and in some cases, sputtering may not be possible.

  The present invention has an excellent feature that a sufficient barrier effect can be obtained even with a fine wiring pitch, and even if the temperature rises due to heat treatment or the like, the barrier characteristics do not change. Thus, it has a remarkable characteristic to effectively suppress the diffusion of copper, so it is useful as a barrier film for high-density copper wiring semiconductors.

It is a figure which shows the analysis (AES) result of Cu diffusion at the time of using the barrier film | membrane of the Ni-20wt% Cr-4.9wt% Ti alloy of Example 1. FIG. It is a figure which shows the analysis (AES) result of Cu diffusion at the time of using the barrier film of the Ni-19.6wt% Cr-5.1wt% Zr alloy of Example 9. FIG. It is a figure which shows the analysis (AES) result of Cu diffusion at the time of using the barrier film of the Ni-19.7 wt% Cr alloy of the comparative example 1.

Claims (10)

  Cr: 5 to 30 wt%, Ti and / or Zr: 1 to 10 wt%, the balance is made of a Ni—Cr based alloy film made of inevitable impurities and Ni, the film thickness is 3 to 150 nm, and the film thickness uniformity is A barrier film for semiconductor wiring, characterized by being 10% or less at 1σ.   Provided on a semiconductor substrate is a barrier film made of a Ni—Cr alloy having a film thickness of 3 to 150 nm and a film thickness uniformity of 10% or less at 1σ, and a copper coating layer formed on the barrier film. The copper wiring for semiconductors characterized by the above-mentioned.   The barrier film made of a Ni—Cr alloy is a Ni—Cr alloy film containing 5 to 30 wt% of Cr, Ti and / or Zr: 1 to 10 wt%, and the balance being inevitable impurities and Ni. The copper wiring for semiconductor according to claim 2, wherein   4. The semiconductor according to claim 2, wherein the copper coating layer formed on the barrier film is an electroless copper plating layer or an electroless copper plating seed layer and an electro copper plating layer formed thereon. Copper wiring.   4. The semiconductor coating according to claim 2, wherein the copper coating layer formed on the barrier film is a copper sputtered film or a seed layer made of a copper sputtered film and an electrolytic copper plating layer formed thereon. Copper wiring.   A barrier film made of a Ni-Cr alloy is formed on a semiconductor substrate by sputtering, and an electroless copper plating layer or an electroless copper plating seed layer and a copper coating layer by electrolytic copper plating are further formed thereon. A method for manufacturing semiconductor wiring.   A barrier film made of a Ni—Cr alloy is formed on a semiconductor substrate by sputtering, and a copper seed layer made of a sputtered copper coating layer or a sputtered film and a copper coating layer formed by electrolytic copper plating are formed on the barrier film. A method for manufacturing semiconductor wiring.   8. The method of manufacturing a copper wiring for a semiconductor according to claim 6, wherein the barrier film made of a Ni-Cr alloy has a film thickness of 3 to 150 nm and a film thickness uniformity of 1 [sigma] of 10% or less.   The barrier film made of a Ni—Cr alloy is a Ni—Cr alloy film containing 5 to 30 wt% of Cr, Ti and / or Zr: 1 to 10 wt%, and the balance being inevitable impurities and Ni. The method for producing a copper wiring for a semiconductor according to any one of claims 6 to 8. Ni—Cr-based alloy containing 5-30 wt% Cr, Ti and / or Zr: 1-10 wt%, the balance being inevitable impurities and Ni, and having a relative permeability of 100 in the in-plane direction of the sputtering surface The sputtering target for semiconductor barrier film formation characterized by the following.

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