JPH0235753A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the level-difference covering property of a conductive substance without deteriorating the inter-layer contacting characteristics so that the cross section of a side wall conductor can be enlarged by depositing a high-melting point metallic or high-melting point metallic alloy thin film inside an inter-layer contact hole at a specific substrate temperature, and then, deposition a conductive substance at another specific substrate temperature. CONSTITUTION:An AlSi thin film is deposited on a substrate provided with a contact hole at a required part. After deposition, a first-layer metallic conductor 8 is formed by working the AlSi thin film to fine wires by dry etching after, for example, a resist pattern is formed. Then an inter-layer insulating film 11 is deposited and a first inter-layer contact hole 12 is formed. After forming the hole 12, a WSi2 thin film 10 is deposited by a sputtering method at a substrate temperature of, for example, 250 deg.C. Lastly, a second-layer AlSi thin film 14 is deposited by an FB sputtering method, high-temperature sputtering method, etc., a substrate temperature of 250 deg.C or higher and a second- layer metallic conductor is formed by working the thin film 10 to fine wires.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a semiconductor device having a plurality of wiring layers, and particularly to a method for manufacturing a semiconductor device that has high reliability even when miniaturized. .

2. Description of the Related Art When semiconductor devices are manufactured using conventional semiconductor device manufacturing methods, aluminum (hereinafter referred to as AI)-based or high-melting point metal-based metal conducting wires are used. Examples of AI-based gold metal conductors are pure A1 or alloys whose main component is AI (
There is a metal conductor wire made by processing a thin film of A1 alloy (hereinafter abbreviated as A1 alloy) into a fine wire.

Examples of high-melting-point metal conductive wires include tungsten (hereinafter referred to as W), molybdenum (hereinafter referred to as Mo), titanium (hereinafter referred to as Mo), and titanium (hereinafter referred to as Mo).
A metal conductor wire made by processing a thin film of a high melting point metal such as T1 (hereinafter referred to as T1) or an alloy of these with silicon (hereinafter referred to as Si) or other substances (hereinafter referred to as high melting point metal alloy) into a fine wire. be.

Of these, the 04 type has the advantage of lower resistance F no.
) and AlSi with copper (hereinafter referred to as Cu) NT
When using an alloy containing elements such as I, it has the advantage that good and stable contact with the Si substrate can be easily obtained. It has been used.

In addition, in order to solve the drawback of AI-based gold-metal conductive wires, such as the deterioration of Shintomo-made conductors when thinned, (1) Al thin film or A1 alloy thin film and other metals, such as refractory metals or refractory metal alloys, A metal conductor wire made by laminating a thin metal film and processed into a thin wire (for example, D, S,
Gardner et al.
IEEE Tan5actlonon Elect
ron Devlcls) yol, 32
．． 1985, p. 174), (2) A metal conductor wire in which an A1 alloy thin film is processed into a fine wire and then a refractory metal scrap film or a refractory metal alloy thin film is deposited on the top and side surfaces of the thin wire.
For example, H, P.

W, He Y et al., 1986 International Electron Technology Meeting
ctron Device Meetin
g), Technical Digestlp
, 50) have also been proposed.

Note that Al, which forms at least a part of the AI-based gold metal conductor material,
Thin films or A1 alloy thin films have generally been deposited by sputtering while maintaining the temperature of the semiconductor substrate during deposition at about 250° C. or lower.

On the other hand, when creating an interlayer contact that connects wiring layers using a conventional semiconductor device manufacturing method, after forming a lower layer metal conductor, an upper layer is placed on a semiconductor substrate on which an interlayer insulating film is deposited and a contact hole is formed. It has been customary to deposit a conductive material into the contact hole at the same time as depositing a metal thin film that will serve as the material for the metal conductor.

A few conventional methods will be described below using drawings.

Conventional Example I FIGS. 15(a) and 15(b) are cross-sectional views showing first and second examples of semiconductor devices manufactured by a conventional method.

In FIG. 15(a), an Al thin film or an A1 alloy thin film is processed into thin wires, and in FIG. 15(b), the first layer AlSi thin wire 5 is formed into a W thin film 7.
The first layer metal conductor 8 is prepared by covering it with a thin layer, and the second layer metal conductor 17 is coated with the usual 2-layer metal conductor.
The first interlayer contact hole 12 was fabricated by processing an Al thin film or A1 alloy thin film deposited by a sputtering method while keeping the plate temperature below 50°C into a thin wire.
The coverage of the conductive material on the sidewalls is poor and the film thickness is extremely thin, and there is a high possibility that disconnections will occur on the sidewalls or that reliability will decrease due to a reduction in the cross-sectional area of the wiring.

Conventional Example 2 FIG. 16 is a sectional view showing a third example of a semiconductor device manufactured by a conventional method.

In this example, the first layer metal conductive wire 8 is fabricated by processing an AI thin film or an A1 alloy thin film into fine wires, and a WSi2 thin film is applied to the entire surface of the substrate including the inside of the first contact hole 12, for example, by sputtering at a substrate temperature of 250° C. or lower. After that, an AI thin film or an A1 alloy thin film is deposited by the usual bath-lid method with the substrate temperature kept below 250"C,
An example is shown in which the second layer metal conducting wire 17 is fabricated by processing a metal thin film in which an AlSi thin film and a WSi2 thin film are laminated into thin wires. In this case, by increasing the thickness of the WSi2 thin film to a certain extent, it is possible to prevent disconnection on the side wall of the first interlayer contact hole 12 and decrease in reliability to some extent. However, it is clearly inferior to the semiconductor device manufactured by the method of the present invention. Furthermore, since the AI thin film or A1 alloy thin film on the side wall of the first interlayer contact hole 12 becomes extremely thin, problems such as increased resistance in this portion arise.

Conventional Example 3 FIGS. 17(a) and 17(b) are cross-sectional views showing fourth and fifth examples of semiconductor devices manufactured by the conventional semiconductor device manufacturing method, respectively.

In Fig. 17(a), the A1 alloy thin film containing Si is
In Figure (b), the first layer metal conductor 8 is fabricated by processing an AI thin film or an A1 alloy thin film that does not contain Si into fine wires, and the second layer metal conductor 17 is formed using a stepped method such as FB sputtering or high temperature sputtering. The second layer metal conductive wire 17 was fabricated by processing the AlSi thin film deposited by a method that improved coverage into fine wires.

In all of these examples, the problem of deterioration of interlayer contact characteristics occurred. In FIG. 17(a), the S
In addition to the occurrence of precipitated grains 9 and hillocks 22, in FIG.
This is due to the fact that hillocks 22 are concentrated in the area immediately below 2.

Conventional Example 4 FIG. 18 is a sectional view showing a sixth example of a semiconductor device manufactured by a conventional semiconductor device manufacturing method.

In this example, the first layer metal conductive wire 8 is fabricated by processing an AI thin film or an A1 alloy thin film into a thin wire, and after forming the W filling material 13, step coverage is performed using FB sputtering, high temperature sputtering, etc. The second layer metal conductive wire 17 was fabricated by processing the AlSi thin film deposited by the improved method into a fine wire. However, the substrate temperature during W deposition was set at approximately 300°C. For this reason, Si precipitated grains and hillocks were generated concentrated in the region immediately below the interlayer contact 12 of the first layer metal conductive wire 8, resulting in a problem of deterioration of interlayer contact characteristics.

Problems to be Solved by the Invention Metal thin films and metal alloy thin films deposited by the sputtering method, which normally maintains the substrate temperature at about 250'C or less, have poor step coverage. In the method of forming an interlayer contact by simultaneously depositing a metal film in the contact hole by depositing a metal thin film that becomes the paulownia material of the metal conductor, especially when using an Al-based metal conductor on the upper layer side, the interlayer The thickness of the metal film on the side wall of the contact hole becomes extremely thin, and the cross-sectional area of the conductor at that portion becomes extremely small. Therefore, there was a high possibility that a wire breakage would occur in this portion or that reliability against electromigration, stress migration, etc. would deteriorate. Moreover, this problem becomes more and more serious as semiconductor devices become smaller. This is because the ratio between the depth and the diameter of the contact hole (hereinafter referred to as aspect ratio) increases, and the reduction in the metal film thickness on the sidewall becomes more significant.

This problem can be solved by depositing a metal thin film, which is the material of the upper metal conductive wire, using a method that provides high step coverage. Therefore, (1) the substrate temperature during deposition was
High-temperature sputtering method to increase the temperature to 00'C or more (for example, Hashizume et al., Proceedings of the 34th Applied Physics Association Conference, 29
p-B-8), (2) FB sputtering method (for example, Kamos
Hida et al., 1986 International
Electron technology.

Chair Meeting° (Internationala
l Electron Device
Meetir+g)1Technical Dig
estl p, 70) and other methods have been proposed.

However, these methods are difficult to actually apply to the manufacture of semiconductor devices because, for example, the following phenomenon occurs when an AI-based gold metal conducting wire is used on the lower layer side.

(1) When an A1 alloy thin film containing Si exists on the surface of the lower metal conductor, heating to a temperature of about 250°C or higher will cause Si precipitate grains to form on the surface of the lower metal conductor exposed at the interlayer contact area. Occur. For this reason, the area of the part where metals are in direct contact with each other in interlayer contact is reduced, resulting in deterioration of contact characteristics.

(2) If an A I i"J film or an A1 alloy thin film is present on the surface of the lower metal conductor, heating it to a temperature of about 250'C or higher will create a high temperature coating on the surface of the lower metal conductor exposed at the interlayer contact area. Density hillocks occur and surface flatness is lost.This deteriorates the adhesion of the conductive material deposited within the contact hole, resulting in deterioration of contact characteristics.

Phenomena such as Si precipitation and hollow spots can occur whenever metal conductors are heated during sintering, interlayer dielectric deposition, or other processes.

However, the effect is particularly large when an interlayer contact hole is formed and the surface of the metal conductive wire is heated in the exposed area. Most of the metal conductor wire is covered with an interlayer insulation film,
This is because, due to the strong stress being applied, Si precipitation, hillocks, etc. are concentrated in the exposed contact hole.

In addition, the high melting point metal thin film or the high melting point metal alloy thin film is A
Because it has better step coverage than A1 thin film or A1 alloy thin film, it is sometimes used to solve the problem of disconnection of metal conductor wires and deterioration of reliability at contact hole portions. However, sputtering or non-selective ch e
m i c a I v a I) Or depo
If the layer is deposited using the CVI method (hereinafter abbreviated as CV I method), the step coverage is incomplete, and as the aspect ratio increases by -1, it will become difficult to apply the layer. - When deposited by a force-selective CVD method (e.g. R6ChOW I141, 1987 (4th)
International I.I.B.I. Multilevel Ink-Connection Conference
IEEE VLSI Multi
vel Interconnection
Conference) + I), 208) Although it has the advantage of extremely high step coverage, there are limits to its application in the manufacture of actual semiconductor devices where interlayer contacts/holes with various different depths exist.

Furthermore, in order to obtain good characteristics in terms of resistivity and other aspects,
High melting point metal thin film or high melting point metal alloy thin film at 250℃
It is customary to carry out the deposition at a substrate temperature of about 100 mL or higher. For this reason, as in the case of using the above-mentioned high temperature sputtering method or FB sputtering method, the problem of deterioration of the interlayer contact characteristics arises.
).

The present inventor has completed the present invention as a result of various ideas and studies in view of the various drawbacks of the conventional semiconductor device manufacturing methods as described above.

Means for Solving the Problems In the method for manufacturing a semiconductor device of the present invention, a high melting point metal thin film or a high melting point metal alloy thin film is deposited in an interlayer contact hole at a substrate temperature of 250'C or less, and then a second layer is deposited.
A conductive material is deposited at a substrate temperature of 50° C. or higher.

Function: In the method for manufacturing a semiconductor device of the present application, a conductive material is deposited in the contact hole between the eyebrows at a substrate temperature of 250°C or higher, so that the conductivity within the interlayer contact hole is improved without deteriorating the characteristics of the interlayer contact. Improves step coverage of materials,
The cross-sectional area of the conductor on the side wall of the contact hole can be increased.

EXAMPLES The present invention will be explained in more detail below based on the drawings.

Embodiment 1 FIG. 1 is a cross-sectional view showing a first example of a semiconductor device manufactured according to the claims of the present invention.

However, here, the first layer metal conductive wire 8 is fabricated by processing the AlSi thin film into a thin wire, and the first contact hole 12 is
Tungsten/silicide (hereinafter W) is applied to the entire surface of the board, including the inside.
After a thin film (denoted as S12) is deposited by sputtering at a substrate temperature of 250°C or lower, for example, by heating the semiconductor substrate during deposition to 250°C or higher using FB sputtering, high-temperature sputtering, etc. AlSi thin film is deposited by an improved step coating method, and AlSi
An example is shown in which the second layer metal conductive wire 17 is fabricated by processing a metal thin film in which a thin film and a W S fa thin film are laminated into thin wires.

The base insulating film 2 is, for example, a silicon oxide film (hereinafter 5I02
(abbreviated as “film”), silicon nitride film, silicon oxynitride film,
A silicon oxide film containing impurities such as phosphorus and boron, or a multilayer insulating film made of a combination thereof, is used. As the interlayer insulating film 11, for example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon oxide film containing impurities such as phosphorus and boron, an organic insulating film such as polyimide, or a multilayer insulating film made of a combination thereof is used. Ru. Although not shown in this figure, the silicon wafer 1 has already been formed with the exception of the platinum metal wiring that is necessary for the semiconductor device.

In the semiconductor device of this example, good characteristics can be obtained even when miniaturization progresses for the following reasons.

(1) Since the AlSi thin film, which is the material for the second layer metal wiring, is deposited using an expensive step coating method, disconnections may occur on the side walls of the first interlayer contact hole 12, and reliability may be affected due to a reduction in the cross-sectional area of the wiring. No deterioration occurs.

(2) The first layer exposed in the first interlayer contact hole 12
Since the surface of the layer metal conductor 8 is covered with the W Si 2 thin film deposited at a substrate temperature of 250°C or lower, even if the AlSi thin film, which is the material for the second layer metal wiring, is deposited at a substrate temperature of 250°C or higher, , interlayer contact 1 of first layer metal conductor 8
No St precipitate grains or hillocks are generated concentrated in the area immediately below the second layer. Therefore, interlayer contact characteristics do not deteriorate.

Although FIG. 1 shows only an example in which the first layer metal conductor 8 is fabricated by processing one layer of AlSi thin film into a thin wire, it is possible to use an AI thin film or one or more of the following, for example, S I + CLl + Ti, etc. It is also possible to use an A1 alloy thin film containing the elements, or it is possible to use a metal thin film in which an AI thin film or A1 alloy thin film and another thin film are laminated so that the top layer is the AI thin film or A1 alloy thin film. is also possible.

Further, although FIG. 1 shows an example in which the second layer metal conducting wire 17 is made of Al-based material, it is also possible to use a high-melting point metal-based material.

Furthermore, although FIG. 1 shows an example in which a WSi2 thin film is deposited on the entire surface of the substrate including the inside of the first interlayer contact hole 12, other refractory metal thin films or refractory metal alloy thin films, such as WsMo.
s Molybdenum silicide (hereinafter referred to as MoSi2)
It is also possible to deposit thin films of titanium silicide (hereinafter referred to as Ti5ia), titanium nitride (hereinafter referred to as TiN). Furthermore, Fig. 1 shows W S deposited on the entire surface of the substrate.
i 2 A that becomes the material for the second layer metal wiring while leaving the thin film
An example was shown in which a lSi thin film was deposited, but after removing the WSi2 thin film in areas other than the vicinity of the interlayer contact,
It is also possible to deposit lSi thin films.

Furthermore, although FIG. 1 shows an example in which a semiconductor device having two layers of metal wiring is manufactured using the method of the present invention, it is of course possible to manufacture a semiconductor device having three or more metal wiring layers. It is possible.

Furthermore, although FIG. 1 shows only an example in which the method of the present invention is used to manufacture a semiconductor device in which a semiconductor element is formed in a Si wafer, for example, a semiconductor element is formed in a GaAs wafer or a semiconductor film formed on a glass wafer. It is also possible to use it for a semiconductor device fabricated with.

The semiconductor device having the structure shown in FIG. 1 is manufactured, for example, by the steps shown in FIG.

That is, first, a base insulating film 2 is deposited on a silicon wafer 1 on which structures necessary for a semiconductor device other than metal wiring have been fabricated.
A thin AlSi film with a thickness of 0.5 to 1 μm is deposited, for example, by sputtering, on a substrate in which contact holes (not shown in the figure) are formed in necessary areas. Then, for example, by dry etching after forming a resist pattern, the AlSi thin film is processed into fine wires to form the first layer metal conductive wire 8 (FIG. 2(a)).

Subsequently, an interlayer insulating film 11 is deposited and a first interlayer contact hole 12 is formed (FIG. 2(b)).

Next, a WSi2 thin film 10 is deposited, for example, by sputtering using a substrate temperature of 250° C. or lower (FIG. 2(C)).

Finally, the second layer AlSi thin film 14 is deposited by a method such as FB sputtering or high-temperature sputtering that improves step coverage by heating the semiconductor substrate during deposition to 250° C. or higher. (d)), by processing it into a thin wire shape and making it the second layer metal conductive wire 17.
A semiconductor device having the structure shown in the figure is obtained.

Example 2 FIG. 3 is a sectional view showing a second example of a semiconductor device manufactured by the method according to the first claim of the present invention. However, here, the first layer metal conductive wire 8 is fabricated by processing an AlSi thin film into a thin wire, and after forming the W filling material 13 in the first contact hole 12, FB sputtering is performed.
The temperature of the semiconductor substrate during deposition, such as high-temperature sputtering, is reduced to 250℃.
An example is shown in which the second layer metal conductive wire 17 is produced by depositing an AlSi thin film by heating it to a temperature of .degree. C. or higher to improve step coverage and processing it into a thin wire.

The W filling material 13 is formed by: (1) forming the first interlayer contact hole 12 by a CVD method at a substrate temperature of 250°C or less;
(2) After depositing a W thin film on the entire substrate surface by sputtering or CVD at a substrate temperature of 250°C or less, etching back is performed to form the first interlayer contact. This is carried out by a method such as removing the W film other than inside the hole 12. Among these, (1) is most suitable for manufacturing semiconductor devices with advanced miniaturization.
This is the method. This is because this method provides the best adhesion. However, the substrate temperature during W thin film deposition was set to 25
In order to maintain the temperature below 0° C., it is necessary to use a reaction gas system containing, for example, tungsten hexafluoride (hereinafter referred to as W Fa) and disilane.

For the same reason as in the first example, the semiconductor device of this example also provides good characteristics even when miniaturization progresses. Furthermore, since the filling material is formed in the first interlayer contact hole 12 and the aspect ratio is reduced, the second
It is possible to easily improve the step coverage of the AlSi thin film that is the material for layered metal wiring.

Although the example in FIG. 3 shows only an example in which W is used as the filling material, it is also possible to use other high-melting point metals or high-melting point metal alloys. Although FIG. 3 shows an example in which only the lower part 173 in the first interlayer contact hole 12 is filled with W, it is also possible to fill it further to the upper part. In this case, the aspect ratio of the first interlayer contact hole 12 is sufficiently small (so that even if the AlSi thin film that is the material of the second layer metal conductor 17 is deposited by a normal sputtering method with poor step coverage, the first interlayer contact hole 12 The decrease in the thickness of the metal thin film on the walls of the 12 interlayer contact holes is small, and there is a possibility that problems such as disconnection and deterioration of reliability will not occur.However, in the actual semiconductor device manufacturing process, contact holes of different depths exist at the same time. and at least selective C
When using the VD method, the depth that can be buried is limited by the depth of the shallowest interlayer contact hole, so the aspect ratio reduction effect in deeper contact holes cannot be sufficiently obtained, and the second layer metal AlS, which is the material of the conductor 17
It is necessary to deposit thin films in a manner that improves step coverage.

Example 3 FIG. 4 is a sectional view showing a first example of a semiconductor device manufactured by the method according to the second aspect of the present invention. However, here, the first metal conducting wire 8 is fabricated by processing a metal thin film in which a MoSi2 thin film is laminated on an AlSi thin film into a thin wire, and the semiconductor substrate temperature during deposition is 250°C by FB sputtering method, high temperature sputtering method, etc. An example is shown in which the second layer metal conductive wire 17 is fabricated by processing an AlSi thin film deposited by a method that improves the step coverage by increasing the thickness to a fine wire.

In the semiconductor device of this example, good characteristics can be obtained even when miniaturization progresses for the following reasons.

(1) Since the AlSi thin film, which is the material for the second metal wiring, is stacked using a high-level step coating method, disconnections may occur on the sidewalls of the interlayer contact hole 12, and reliability may deteriorate due to a reduction in the cross-sectional area of the wiring. No deterioration occurs.

(2) Since the surface of the first layer metal conductor 8 is covered with the MoSi2 thin wire 8, the surface of the first layer metal conductor 8 is covered with the MoSi2 thin wire 8.
Even when heated to a temperature of 50° C. or higher, Si precipitate grains and hillocks do not concentrate in the region immediately below the interlayer contact 12 of the first layer metal conductor 8. Therefore, interlayer contact characteristics do not deteriorate.

(3) For example, by performing /interpolation after forming the first layer metal conductive wire 8, Si precipitated grains are uniformly generated in the first layer AlSi thin wire 5, and Si precipitates are formed in the area directly under the interlayer contact hole 12.
Even when precipitated grains exist, the precipitated grains are MoSi2 thin wires 6
It is buried under the metal conductor wire 8 and is not exposed to the surface of the first layer metal conductor wire 8. Therefore, interlayer contact characteristics do not deteriorate.

In addition, FIG. 4 shows a single layer of AlSi thin film and a single layer of Mo.
Although only an example was shown in which the first layer metal conductor 8 was produced by processing the metal thin film into a thin wire by laminating the 5it thin film with the Movi2 thin film on top, it is also possible to laminate three or more layers of thin films. . Furthermore, instead of the AlSi thin film, it is also possible to use an Al thin film or an A1 alloy thin film containing one or more elements of Si+Cu, Ti, etc., and instead of the Mos+2 thin film, it is also possible to use other high melting point metals.
It is also possible to use a metal film or a refractory metal alloy thin film.

Although FIG. 4 shows an example of manufacturing a semiconductor device with two layers of metal wiring using the method of the present invention, it is of course possible to manufacture a semiconductor device with three or more metal wiring layers. It is possible.

Further, although FIG. 4 shows an example in which the second layer metal conducting wire 17 is made of A1 type wire, it is also possible to use a high melting point metal type wire.

The semiconductor device having the structure shown in FIG. 4 is manufactured, for example, by the steps shown in FIG.

That is, first, a base insulating film 2 is deposited on a silicon wafer 1 on which structures necessary for a semiconductor device other than metal wiring have been fabricated.
0.5-1 μm thick AlSi thin film 3 and 0.5-1 μm thick AlSi thin film 3 and 0.5-1 μm thick contact holes (not shown in this figure) were formed on the substrate. 03-0. A MoSi2 thin film 4 having a thickness of 3 μm is deposited, for example, by sputtering (FIG. 5(a)).

Subsequently, for example, by dry etching after forming a resist pattern, the Al5i thin film 3 and M
The oSi2 thin film 4 is added to the first layer AlSi thin wire 5 and the MoSi2 thin wire 6 to form the first layer metal conducting wire 8 (
Figure 5(b)).

Next, an interlayer insulating film 11 is deposited and a first interlayer contact hole 12 is formed.
A hole is drilled (Fig. 5(C)).

Finally, the second layer AlSi thin film 14 is deposited using a method such as FB sputtering or high temperature sputtering that improves step coverage by heating the semiconductor substrate during deposition to 250° C. or higher. (d)) The semiconductor device having the structure shown in FIG. 4 is obtained by processing it into a thin wire shape to form the second layer metal conductive wire 17.

Embodiment 4 FIG. 6 is a sectional view showing a second example of a semiconductor device manufactured by the tube 2 of the present invention and the method claimed in the claims. However, here, the W filling material 13 is placed inside the first contact hole ■2.
An example of a semiconductor device formed with the following is shown below.

The W filling material 13 is formed in the same way as in the case of FIG.
(1) Selectively deposit W film only in the first interlayer contact hole 12 by CVD method; (2) Deposit W film over the entire substrate surface by sputtering method or CVD method, and then perform etchback to remove the W film. This is carried out by a method such as removing the W film other than in the one-layer contact hole 12. However, in the case of this example, it is possible to raise the substrate temperature during W deposition to 250° C. or higher, and a gas atmosphere containing, for example, WF6 and silane (hereinafter referred to as SiH4) for performing CvD can be adopted. Can be done.

It is also possible to use a high melting point metal or a high melting point metal alloy other than W as the filling material.

In the semiconductor device shown in FIG. 6, good characteristics can be obtained even when miniaturization progresses for the same reason as in the example shown in FIG. Moreover, as in the example of Fig. 3, the second
It is possible to easily improve the step coverage of the AlSi thin film that is the material for layered metal wiring.

Embodiment 5 FIG. 7 is a sectional view showing a first example of a semiconductor device manufactured by the method according to the third claim of the present invention. However, here, the AlSi thin film is processed into the first AlSi thin wire 5, and the top and side surfaces thereof are covered with the W thin film 7 to produce the first layer metal conductive wire 8, and then the first layer metal conductive wire 8 is fabricated by FB sputtering method, subtemperature sputtering method, etc. Semiconductor substrate temperature during deposition to 250"
An example is shown in which the second layer metal conductive wire 17 is fabricated by processing an AlSi thin film deposited by a method in which step coverage is improved by heating to C or higher to form a thin wire.

In the semiconductor device of this example, good characteristics can be obtained even when miniaturization progresses for the following reasons.

(1) Since the AlSi thin film, which is the material for the second layer metal wiring, is deposited using a step coating method, disconnections may occur on the side walls of the interlayer contact hole 12, and reliability may decrease due to a reduction in the cross-sectional area of the wiring. will not occur.

(2) Since the surface of the first layer metal conductor 8 is covered with the W thin film 7, the surface of the first layer metal conductor is heated to a temperature of 250°C or higher when depositing the A1 alloy thin film, which is the material for the second layer metal wiring. Even when heated to a high temperature, Si precipitate grains and hillocks do not concentrate in the region immediately below the interlayer contact 12 of the first layer metal conductor 8.

Therefore, interlayer contact characteristics do not deteriorate.

(3) For example, by performing sintering after forming the first layer metal conductive wire 8, Si is uniformly distributed in the first ffAISi thin wire 5.
Precipitated grains are generated and S
Even if precipitated grains are present, the precipitated grains are embedded in the W thin film 7 and do not tuft onto the surface of the first layer metal conductive wire 8. Therefore, interlayer contact characteristics do not deteriorate.

Although FIG. 7 shows only an example in which the top and side surfaces of the thin metal wire processed from an AlSi thin film are covered with a W thin film, an AI thin film or, for example, a Si thin film may be used instead of the AlSi thin film.
It is also possible to use an A1 alloy thin film containing one or more elements such as , Cuy Ti, etc.
It is also possible to use other refractory metal thin films or refractory metal alloy thin films in place of the thin films 11.

Although FIG. 7 shows an example of manufacturing a semiconductor device with two layers of metal wiring using the method of the present invention, it is of course possible to manufacture a semiconductor device with three or more metal wiring layers. It is possible.

Further, although FIG. 7 shows an example in which the second layer metal conducting wire 17 is made of an AI-based material, it is also possible to use a high-melting point metal-based material.

The semiconductor device having the structure shown in FIG. 7 is manufactured, for example, by the steps shown in FIG.

That is, first, a base insulating film 2 is formed on a silicon wafer 1''2 on which structures necessary for a semiconductor device other than metal wiring have been fabricated, and contact holes (not shown in this figure) are opened in the necessary parts. film thickness 0.55-1a on a substrate
A first AJAISi film 3 is deposited by, for example, sputtering (FIG. 8(a)).

Next, for example, by dry etching after forming a resist pattern, the eleventh AIsi thin film 3 is processed into the first layer AlSi thin wire 5, and after the resist is removed, CVD is performed in an atmosphere containing, for example, WF6 and SiH4 gas. A W thin film 7 with a thickness of 330-100n is selectively deposited only on the top and side surfaces of the first EAiSjffll wire 5 to form the first layer metal conductor 8 (FIG. 8(b)
)).

Next, a first interlayer contact hole 12 is opened in the interlayer insulating film 11 (FIG. 8(C)).

Finally, the second layer AlSi thin film 14 is deposited by a method such as FB sputtering or high-temperature sputtering that improves step coverage by heating the semiconductor substrate during deposition to 250° C. or higher. (d)), by processing it into a thin wire shape and making it the second layer metal conductive wire 17.
A semiconductor device having the structure shown in the figure is obtained.

Here, the top and side surfaces of the first layer AlSi thin wire 5 are CV
Although only an example of coating with the W thin film 7 selectively deposited by the D method is shown, it is also possible to perform the coating with another refractory metal thin film or a refractory metal Fj film, and the deposition can also be performed using the C method.
It is also possible to use a method other than VD, for example, a sputtering method. However, if the deposition is performed using a non-selective method, it will be necessary to add a step to remove the thin film deposited on unnecessary areas.

FIG. 9 shows the yield of interlayer contacts in the semiconductor device shown in FIG. 7 and a semiconductor device manufactured by the conventional method, that is, in which the first layer metal conductor is an AlSi thin wire that is not covered with a W thin film. The results are shown below. W thin film 7
The film thickness of is f 00 nm, and the second layer AlSi thin film 1
4 is FB sputtering method.

Specifically, the film was deposited by sputtering on a substrate heated to 300'C in advance while applying an RF bias. For the first interlayer insulation 11, a plasma 5jO2 film with a film thickness of 800 nm was used. However, the yield was investigated using a contact chain with 10,000 monthly contacts connected in series, and the resistance per interlayer contact was 1Ω.
It was determined that the product was defective if the following conditions were met.

As can be seen from Figure 9, when the interlayer contact hole diameter was reduced from 1.2 μm to 0.78 μm without coating with the W thin film, the yield decreased sharply from more than 95% to approximately 60%. On the other hand, when coating is performed, almost no deterioration is observed, and the method for manufacturing a semiconductor device of the present invention provides good interlayer contact even when miniaturization progresses.
It is clear that this method is effective for improving i-ness.

Embodiment 6 FIG. 10 is a sectional view showing a second example of a semiconductor device manufactured by the method disclosed in Patent No. 8111 of the present invention. However, here, AIS', i thin film is the first layer A
Processed into a lSi thin wire 5, its top and side surfaces are coated with a W thin film 7.
The first layer metal conductive wire 8 is prepared by coating with a W Si 2 thin film deposited by sputtering, for example, and a W Si 2 thin film deposited by a method that improves step coverage, such as FB sputtering or high temperature sputtering. An example is shown in which the second layer metal conducting wire 17 is fabricated by processing a metal thin film laminated with an AlSi thin film into a thin wire. However, in order to improve the film quality, the substrate temperature during W Si 2 film deposition was
The temperature was set at about 00°C.

When depositing an AlSi thin film by FB sputtering method, high temperature sputtering method, etc., the contact hole of the AlSi thin film can be formed by depositing a high melting point metal thin film 11 or a high melting point metal alloy thin film in the contact hole as in this example. It is possible to further improve the coating properties inside. Similar effects can be obtained when a high melting point metal thin film or a high melting point metal alloy thin film other than WSi2 is used. The appropriate thickness of the high melting point metal thin film or high melting point metal alloy thin film is about 550 to 300 nm.

Embodiment 7 FIG. 11 is a sectional view showing a third example of a semiconductor device manufactured by the method according to the claims of the third aspect of the present invention. However, here, the AlSi thin film and M are used.

The metal thin film laminated with the Si2 thin film is processed into a thin wire, and the top and side surfaces are covered with the W thin film 7.
A layered metal conductive wire 8 is produced, and I? An example is shown in which the second layer metal conductive wire 17 is fabricated by processing into a thin wire a metal thin film laminated with an AlSi thin film deposited by a method that improves step coverage such as 'B sputtering method or high temperature sputtering method. ing.

It is also possible to cover a thin metal wire obtained by processing a metal thin film having a laminated structure with the W thin film 7 as in this example. Also here, -layers of AlSi thin film and McSi2
Although only an example in which the thin films are stacked with the MoSi2 thin film on top is shown, it is also possible to reverse the stacking order or to stack three or more thin films. Furthermore, instead of the AlSi thin film, an A1 thin film or, for example, S 11 CLI
It is also possible to use an A1 alloy thin film containing one or more elements such as TTi, etc., or MO8
It is also possible to use other refractory metal thin films or refractory metal alloy thin films instead of the No. 12 thin film.

Example 8 FIG. 12 is a sectional view showing a fourth example of a semiconductor device manufactured by the method according to the third claim of the present invention. However, here, W is embedded in the first contact hole 12.
In the semiconductor device shown in FIG. 12, which shows an example of a semiconductor device formed with the structure No. 3, good characteristics can be obtained even when miniaturization is advanced, for the same reason as in the example shown in FIG. Furthermore, as in the case of the example shown in FIG. 3, it is possible to easily improve the step coverage of the metal thin film that is the material of the second layer metal wiring.

Further, although only an example in which W is used as the filling material is shown here, it is also possible to use other refractory metals or refractory metal alloys.

The semiconductor device having the structure shown in FIG. 12 is manufactured, for example, by the steps shown in FIG. 13.

That is, first, a first layer metal conductor 8 is fabricated on a Si wafer 1'' on which a base insulating film 2 is deposited according to the same steps as in the case of FIG.
Interlayer contact holes 12 are created (FIG. 13(a)).

Next, for example, the semiconductor substrate is heated to 250-350'C and CVD is performed in an atmosphere containing W F 6 and 5iHa to selectively deposit only in the first interlayer contact hole 12, thereby forming the W buried shrine 13. (Fig. 13(b)).

Finally, a second layer AlSi thin film 14 is deposited, for example, by sputtering (FIG. 13(c)), and processed into a thin wire shape to form a second layer metal conductive wire 17, thereby obtaining a semiconductor device having the structure shown in FIG. 12.

Here, we have shown only an example in which the filling material was fabricated by selectively depositing W only in the interlayer contact hole 12 using the CV i) method, but it was deposited on the entire surface of the substrate and then etched back to form J+υ. It is also possible to use a method of removing the film in areas other than the intercontact holes 12, or to use a method other than CVD, for example, sputtering, to deposit the W film.

Further, FIG. 12 shows an example in which W is buried up to 80% or more of the first interlayer contact hole 12 to sufficiently reduce the aspect ratio. In this case, the second layer AlSi thin film 14
Even if the step coverage is poor, the decrease in the thickness of the metal thin film on the side wall of the first interlayer contact hole 12 is small, and problems such as disconnection and reduced reliability do not occur. Therefore, the second JifflAIS
It is also possible to deposit the i-thin film by a conventional sputtering method.

However, in the actual semiconductor device manufacturing process, contact holes with different depths often exist at the same time, and at least when the filling material is formed by selective CVD, the aspect ratio reduction effect in shallow contact holes is Even if a sufficient amount is obtained, the effect of reducing the aspect ratio in deeper contact holes cannot be sufficiently obtained. In this case, it is necessary to deposit the second layer AlSi thin film 14 by a method that improves step coverage.

Example 9 FIG. 14 is a sectional view showing a fifth example of a semiconductor device manufactured by the method according to the third claim of the present invention. However, here, an example was shown in which a semiconductor device having three metal wiring layers was manufactured. Then, the first layer metal conductive wire 8 is
1A] A thin AlSi film is prepared by coating the negative side and side surface of the Si thin wire 5 with a W thin film 7, and the second layer metal conductor wire 17 and the third layer metal conductor wire 21 are both deposited by a normal sputtering method. Produced by processing,
Then, the W filling material 13 was formed only in the second interlayer contact hole 19 connecting the first layer metal conductor 8 and the third layer metal conductor 17. Both the second layer metal conductor 17 and the third layer metal conductor 21 are deposited using AlS using a normal sputtering method.
It is fabricated by adding a thin film to a thin wire, and is formed in the first contact hole 12 and in the second layer metal conductive wire 17 and the third layer metal conductive wire 17.
Third interlayer contact hole 20 connecting to layer metal conductor 21
No embedded material was formed in the first and third
This is because the aspect ratio of the interlayer contact hole is small, and even without special measures, disconnection does not occur on the side wall of the interlayer contact hole, and reliability does not deteriorate due to a reduction in the cross-sectional area of the wiring. Also, for that reason, the second
The layer metal conducting wire 17 was not coated with a W thin film.

Effects of the Invention The method for manufacturing a semiconductor device of the present invention has the following two configurations, and even when the method according to any one of the first, second, and third claims is used, the semiconductor device can be manufactured. It is possible to solve the problem of disconnection or reduced reliability of the metal conducting wire on the upper layer side of the interlayer contact hole, which becomes more serious as the miniaturization of the interlayer contact hole progresses, without deteriorating the interlayer contact characteristics.

Moreover, the method is easy and does not significantly reduce productivity.

Therefore, the method of manufacturing a semiconductor device of the present invention is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first example of a semiconductor device manufactured by the method claimed in claim 1 of the present invention, and FIG. 2 is a sectional view showing an example of the second step for manufacturing the semiconductor device. The cross-sectional view and Figure 3 are the patent 'FB!' of the tube 1 of the present invention. FIG. 4 is a cross-sectional view showing a second example of a semiconductor device manufactured by the claimed method; FIG. FIG. 5 is a process cross-sectional view showing an example of the process for manufacturing the semiconductor device, and FIG. 6 is a cross-sectional view showing a second example of the semiconductor device manufactured by the present invention tube 2 and the method claimed in the claims. , 7th
The figure is a cross-sectional view showing a first example of a semiconductor device manufactured by the method according to claim 3 of the present invention, and FIG. 8 is a process cross-sectional view showing an example of the process for manufacturing the semiconductor device.
FIG. 9 is a characteristic diagram showing the results of investigating the yield of interlayer contacts in the semiconductor device shown in FIG. 7 and a semiconductor device manufactured by a conventional method, and FIGS. Cross-sectional views showing second, third, and fourth examples of semiconductor devices manufactured by the method according to claim 3 of the present invention, and FIG. 13 is an example of the process for manufacturing the semiconductor device of FIG. 12. FIG. 14 is a cross-sectional view showing a fifth example of a semiconductor device manufactured by the method according to claim 3 of the present invention; FIG.
are the first of the semiconductor devices manufactured by the conventional method, respectively.
16 is a sectional view showing a third example of a semiconductor device manufactured by a conventional method, and FIG. 17 is a sectional view showing a third example of a semiconductor device manufactured by a conventional method. FIG. 18 is a sectional view showing a sixth example of a semiconductor device manufactured by a conventional semiconductor device manufacturing method. DESCRIPTION OF SYMBOLS 1... Si wafer, 2... Base insulating film, 3... First JiAISi thin film, 4... MoSi2 thin film, 5...
...First layer AlSi thin wire, 6...MoSi2 thin wire,
7... W thin film, 8... First layer metal conducting wire, 9...
・Si precipitate grains, 10... WSi2 thin film, 11... First interlayer insulating film, 12... First interlayer contact hole, 13
...W filling material, 14...second layer AlSi thin film,
15...W S t 2 thin wire, 16... 2nd layer Al
Si thin wire, 17...Second layer metal conductor wire, 18...Second layer
Interlayer insulating film, 19... second interlayer contact hole, 20.
...Third layer contact hole, 21...Third layer metal conducting wire, 22... Hillock. Name of agent: Patent attorney Shigetaka Kurino (1 person) Figure 8 Figure 10 Figure 11 Figure 12 Figure 14 Figure 13 Figure 15 Figure 12 vtt, r/l contact hole No. Figure 16 Figure 17 (of) /Z 1st glabellar gontagt foramen fJ)! ? Interlayer contact com ＼ 22 Hirozuku

Claims (3)

[Claims] (1) A step of manufacturing at least one layer of metal conductive wire by processing a metal thin film whose outermost surface is an aluminum thin film or an alloy thin film containing aluminum as a main component into a fine wire; A step of forming an interlayer contact hole for connecting to at least one of the metal conductive wires located in the upper layer, and forming a high melting point metal thin film or an alloy thin film mainly composed of a high melting point metal in the interlayer contact hole at 250°C. and a step of depositing a conductive substance at a substrate temperature of 250° C. or higher after the deposition of the high melting point metal thin film or alloy thin film containing the high melting point metal as a main component. A method for manufacturing a semiconductor device. (2) At least one layer of the metal conducting wire is formed by forming an aluminum thin film or an alloy thin film mainly composed of aluminum, and a high melting point metal thin film or an alloy thin film mainly containing a high melting point metal, and the uppermost layer is a high melting point metal thin film or an alloy thin film mainly composed of a high melting point metal. A step of fabricating a laminated metal thin film, which is an alloy thin film mainly composed of a high-melting point metal, by processing it into a thin wire; forming an interlayer contact hole for connection to at least one of the above, and forming a conductive substance on the substrate with the first metal conductive wire surface exposed in the interlayer contact hole at a substrate temperature of 250° C. or higher. A method for manufacturing a semiconductor device, comprising a step of depositing. (3) At least one layer of the metal conductor wire is processed into a thin wire using an aluminum thin film, an alloy thin film mainly composed of aluminum, or a metal thin film laminated with these and other thin films, and the top and side surfaces of the thin wire have a high melting point. A step of manufacturing by coating with a metal thin film or an alloy thin film containing a high melting point metal as a main component, and connecting the first metal conductive wire and at least one of the metal conductive wires located in a layer above the metal conductive wire. and a step of depositing a conductive material on the substrate in which the surface of the first metal conductive wire is exposed in the interlayer contact hole at a substrate temperature of 250° C. or higher. A method for manufacturing a semiconductor device.