JPH0851152A - Manufacture of electrode wiring and processing equipment thereof - Google Patents

Abstract

PURPOSE:To form a wiring metal into a connecting hole section having a high aspect ratio with a sufficient coating rate by a method wherein a metallic region machined in a specified shape is formed, the region of a substance of a different kind uniformly covering the metallic region is applied and formed, stress is applied and the metallic region is deformed. CONSTITUTION:A polycrystalline silicon electrode wiring 21 and a tungsten wiring are shaped onto a substrate 11, a foundation insulating film 32 for forming a wiring by this invention is formed, and a connecting hole 41 with a lower layer is bored. An electrode wiring 23 is buried and shaped into the connecting hole 41 by a forming process of a metallic film 23 having a high ductility consisting of Al, Cu, an alloy thereof, etc., and succeeding pressure treatment. That is, the region of a substance 24 of a different kind uniformly coating the region of the metallic film 23 or the surface of the substrate 11 is applied and formed or mounted, stress having a component in the vertical direction is applied to the surface of the substrate 11, and the region of the metallic film 23 is deformed. Accordingly, the connecting hole 41 having a high aspect ratio can be filled with a metal abounding in ductility by a simple treatment, thus realizing an improvement in the reliability of the connecting hole wiring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device electrode wiring, and more particularly to a method and a processing apparatus for manufacturing electrode wiring suitable for forming a vertical connection hole wiring having a high aspect ratio.

[0002]

2. Description of the Related Art In order to cope with high integration of semiconductor devices, a method of forming multiple layers in wiring is adopted. The aspect ratio (ratio of depth / hole diameter) of the connection hole between the layers in the multilayer wiring and the connection hole with the connection electrode with the active portion formed in the semiconductor substrate is increased as the integration degree is increased. It is difficult to form a film with sufficient coverage in such a high aspect ratio contact hole by the sputtering method, which is the current typical metal film forming method, and some new methods or conventional methods have been improved. The methods have been studied and are being applied. The representative ones are listed below.

Formation of Blanket W (or Al) Film by CVD Method Formation of Plug Electrode Wiring by Selective CVD Method (W or Al) Filling of Cavity by Bias or High Temperature Sputtering Method (Al Alloy) Cavity by High Temperature Treatment After Film Formation (Al alloy) The filling of the concave portion by the pressure treatment after the film formation (Al alloy) is based on the sputtering method and is relatively easy to control.

[0004]

The method of [Problems to be Solved by the Invention]
-225829, JP-A-5-29470, and Japanese Patent Application No. 4-
It is proposed in the specification of 229723. Basically, the substrate on which the film is formed is isotropically pressed to press the Al alloy into the recess, but the following problems remain.

The embedding property is insufficient and the film is not sufficiently pushed unless it is in a continuous and airtight state. When the membrane deforms and breaks, it is not embedded any more. In order to fill deep recesses, a process of forming an Al alloy film having a thickness more than necessary, once filling, and then partially removing it is necessary.

Since the isotropic pressurization method uses gas or liquid as a pressure medium, the degree of danger (explosion, etc.) of the device is high. High temperature is required to reduce the pressure.

An object of the present invention is to provide a method of manufacturing an electrode wiring which has a simple process, good controllability, and good embedding characteristics.

[0008]

In order to achieve the above object, according to the present invention, a step of forming a highly ductile metal film of Al, Cu, Ag, Au, etc., and a recess formed on the surface of the substrate by a subsequent pressure treatment. The electrode wiring is buried and formed. At that time, in particular, if a buffer layer made of a different material having a smaller elastic modulus than the metal to be deformed is provided on the metal film, it becomes possible to use a uniaxial compressive force for pressurization, and the high pressure can be relatively easily applied. Since this can be achieved, the processing temperature can be lowered and the processing speed can be increased, and the above and particularly the problems can be solved. Further, if a buffer layer of a different material having a higher elastic modulus than the metal to be deformed is provided on the metal film, a high embedding property can be obtained even if an isotropic pressure is applied without increasing the thickness of the metal layer. Therefore, the above problems can be solved.

[0009]

Operation: Face-centered cubic metal (Al, Cu, Ag, Au
And its alloys) are rich in ductility, and when stress is applied, they deform to some extent without breaking. By utilizing this property, the metal film deposited on the uneven substrate can be transformed into a conformal shape that conforms to the shape of the substrate surface, and the cavities and the like generated during the deposition of the metal film can be eliminated. . In order to most effectively deform the metal film, it is necessary to set the direction of the applied stress to be appropriate. Isotropic pressure or unidirectional (uniaxial) pressure can be easily generated by the pressurizing method that can be usually used, but intermediate pressure between both is difficult to generate. Actually, it is desirable to use such an intermediate direction. Is a pressure with.

The embedding of holes will be described in some detail. Efficient embedding cannot be achieved unless the metal around the hole is moved parallel to the substrate surface toward the hole, and the metal immediately above the hole is moved toward the inside of the hole perpendicularly to the substrate surface.
It is most desirable to apply a necessary force in the moving direction corresponding to the location of the metal film, but it is very difficult to control and change the direction of the force in reality. Therefore, it is considered most effective to apply stress in an intermediate direction.

According to the method using the buffer layer of the present invention, it is possible to apply a pressure in a desired direction even with a normal, isotropic or unidirectional pressure device. When an isotropic pressure device is used, the buffer layer should be made of a material that is more difficult to deform than the metal film (has a large elastic constant). When a unidirectional pressure device is used, the buffer layer should not be deformed. It is preferable to form the buffer layer with a material that is easy (having a small elastic constant).

[0012]

【Example】

(Embodiment 1) FIGS. 1 to 4 are sectional views of a silicon semiconductor device showing an embodiment of the present invention. A wiring system was manufactured through steps in the order of FIG. 1 to FIG.

This wiring system was prepared by the following ordinary silicon semiconductor device manufacturing process and the process of the present invention. That is, after forming the active portion on the surface of the silicon substrate 11,
Polycrystalline silicon electrode wiring 21, with an insulating film layer interposed,
A tungsten wiring 22 is formed, a base insulating film 32 for forming the wiring of the present invention is formed, and a connection hole 41 with a lower layer is formed.
Opened. Then, the Al-1% Si alloy film 23 was formed by the sputtering method. Since the step coverage is low in the sputtering method, as shown in FIG. 1, the inside of the connection hole was not filled and a cavity remained. The PIQ layer 24 was formed on the surface of the substrate by spin coating and baked (heated) at 450 ° C.

As shown in FIG. 2, this substrate was set under the head 51 of a hydraulic press and pressure was applied. When the cross section of the substrate was observed in this state, the cavities in the connection holes disappeared and the connection holes were filled with Al alloy 23.

The minimum pressure for filling the cavity of the connection hole with Al depends on the pressurizing time, the structure and film thickness of the element, and the type of metal, but for Al alloys, it is about 100 MPa at room temperature, and it is necessary to raise the temperature. The pressure gradually decreases, and becomes about 50 MPa at 200 ° C. (about 1/2 of the melting point in absolute temperature), becomes lower at higher temperature, and drops to about 20 MPa at 400 ° C.

After that, the substrate was removed from the head 51 of the hydraulic press machine, and the plasma ashing device using oxygen was used for PI.
The Q layer 24 is removed to obtain the structure shown in FIG. Subsequently, the Al region 23 is patterned into a desired shape by photoetching as shown in FIG. When the ratio of the cavities in the Al region is small, after patterning as described above, P
An IQ layer may be provided and pressure may be applied.

Although this embodiment was carried out using an Al-1% Si alloy film, pure Al, Al--Cu (-Si) alloy, etc. can be embedded under substantially the same conditions. In addition, Al-Ge
For example, alloys having a very low eutectic temperature (424 ° C.) can be embedded at a temperature lower than the above conditions. Also,
It is possible to similarly embed a laminated film in which layers of refractory metal are provided above and below these Al alloy layers. Although there are some variations depending on the material and the film forming conditions as described above, with an alloy containing Al as a main component, this treatment method enables filling with sufficient reliability.

Further, a material having a melting point higher than that of an Al alloy can be similarly applied if there is no problem such as influence on the base substrate. For example, with copper, a similar effect could be obtained at 400 to 500 ° C. or higher.

The elastic constant of PIQ is 1/10 or less of that of Al, and good embedding can be realized when the film thickness is in the range of about 100 to 100 times that of Al.

As a simpler method, it is possible to embed by pressing with a roller or the like. In that case, the embedding characteristics were better when the buffer layer thickness was made thicker and the film thickness of Al was several times or more.

(Embodiment 2) FIGS. 5 to 8 are sectional views of a silicon semiconductor device showing an embodiment of the present invention. A wiring system was manufactured through steps in the order of FIG. 5 to FIG. This wiring system was also manufactured by the following ordinary silicon semiconductor device manufacturing process and the process of the present invention as in the first embodiment.

That is, after forming the active portion on the surface of the silicon substrate 11, the polycrystalline silicon electrode wiring 21 and the tungsten wiring 22 are formed with the insulating film layer interposed therebetween to form the underlying insulating film for forming the wiring of the present invention. 32 was formed, and the connection hole 41 with the lower layer was opened. At the same time, a groove was formed at the position where the wiring should be formed. Then, the Al-1% Si alloy film 23 was formed by the sputtering method. Since the step coverage is low in the sputtering method, as shown in FIG. 5, the inside of the connection hole was not filled and a cavity remained. A Teflon sheet 25 that had been sufficiently pretreated (smoothed, washed, deaerated, etc.) was placed on the surface of this substrate.

As shown in FIG. 6, this substrate was set under the head 51 of a hydraulic press and pressure was applied. When the cross section of the substrate was observed in this state, the cavities in the connection holes disappeared and the connection holes were filled with Al. In this case as well, the pressure required for filling could be lowered by heating.

After that, the substrate is removed from the head 51 of the hydraulic press and the Teflon sheet is removed to obtain the structure shown in FIG.

Al2 remaining in the groove other than the groove for forming the wiring
3 is removed by polishing or etchback as shown in FIG. 8, the Al region patterned into a desired shape
23 'is formed.

The elastic constant of Teflon is 1/10 or less of that of Al, and good embedding can be realized when the film thickness is in the range of about 100 to 100 times that of Al.

(Embodiment 3) FIGS. 9 to 11 are sectional views of a silicon semiconductor device showing an embodiment of the present invention. Figure 9
Then, the wiring system was manufactured through the steps in the order of FIG. This wiring system was created by the following ordinary silicon semiconductor device manufacturing process and the process of the present invention.

That is, as shown in FIG. 9, after forming an active portion on the surface of the silicon substrate 11, an electrode wiring 21 and a tungsten wiring 22 of polycrystalline silicon are formed with an insulating film layer interposed therebetween to form the wiring of the present invention. A base insulating film 32 for forming the film is formed, and a connection hole 41 with the lower layer is opened. Continue to A
The 1-1% Si alloy film 23 and the W layer 26 were formed by laminating by a sputtering method. Since the step coverage is low in the sputtering method,
As shown in FIG. 9, the inside of the connection hole was not filled with the Al alloy and a cavity remained.

As shown in FIG. 10, this substrate was set in a pressure tank and pressure was applied. When the cross section of the substrate was observed in this state, the cavities in the connection holes disappeared and the connection holes were filled with Al.

The minimum pressure for filling the cavity of the connection hole with Al depends on the pressurizing time, the structure and film thickness of the element, and the kind of metal, but it is about 300 MPa at room temperature, and gradually decreases when the temperature is raised to 200 At 200C (about 1/2 of the melting point in absolute temperature), the pressure is about 200 MPa, at higher temperatures, the pressure is lower, and at 400C, it is about 100 MPa.

Subsequently, the Al region 23 and the W region 26 are patterned into a desired shape by a photoetching method as shown in FIG. If the W region 26 is too thick, it is patterned after removing this region. When the proportion of the cavities in the Al region is small, the patterning and the pressurizing step may be performed before and after the patterning is performed, and then the pressure may be applied.

The elastic constant of W is about 5 times that of Al. Good embedding can be realized when the film thickness is in the range of about 10 times that of Al.

[0033]

According to the present invention, a high aspect ratio contact hole can be filled with an Al alloy or a metal rich in ductility by a simple process, and the reliability of the contact hole wiring can be improved. It is extremely useful for realizing various semiconductor devices with high integration density.

[Brief description of drawings]

FIG. 1 is a sectional view showing a wiring forming process according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a wiring forming process according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a wiring forming process according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a wiring forming process of an example of the present invention.

FIG. 5 is a cross-sectional view showing a wiring forming process of an example of the present invention.

FIG. 6 is a cross-sectional view showing a wiring forming process of an example of the present invention.

FIG. 7 is a cross-sectional view showing a wiring forming process of an example of the present invention.

FIG. 8 is a cross-sectional view showing a wiring forming process of an example of the present invention.

FIG. 9 is a cross-sectional view showing a wiring forming process of an example of the present invention.

FIG. 10 is a cross-sectional view showing a wiring forming process of an example of the present invention.

FIG. 11 is a cross-sectional view showing a wiring forming process of an example of the present invention.

[Explanation of symbols]

11 ... Silicon substrate, 21 ... Polycrystalline silicon electrode wiring,
22 ... Tungsten wiring, 23 ... Al-1% Si alloy film, 24 ... PIQ resin layer, 26 ... W film, 31, 32 ... Interlayer insulating film, 41 ... Connection hole part, 51 ... Head of hydraulic press device.

Claims (6)

[Claims] 1. A method of manufacturing electrode wiring, which further comprises the following steps. (A) a step of forming a layered or predetermined-shaped metal region on a substrate having a concave portion, and (b) a region of a different substance that uniformly covers the metal region or the surface of the substrate. Forming or installing, (c) applying a stress having a vertical component to the surface of the substrate to deform the metal region. 2. The method of manufacturing an electrode wiring according to claim 1, wherein the elastic modulus of the different substance is smaller than that of metal, and the main component of the stress is a compressive force in a direction perpendicular to the substrate surface. 3. The method of manufacturing an electrode wiring according to claim 1, wherein the elastic modulus of the different substance is larger than that of metal, and the stress is an isotropic compressive force. 4. The method of manufacturing an electrode wire according to claim 1, wherein stress is applied in a heated state to deform the metal region. 5. The method for manufacturing an electrode wiring according to claim 1, 2, 3 or 4, wherein the deformed metal region is made of aluminum, copper, silver, gold, platinum, palladium, nickel or an alloy thereof. 6. A mechanism for transporting a substrate which has been subjected to the treatments of (a) and (a) and (b) and setting it at a predetermined position, and a treatment of (c) at a predetermined temperature. Mechanism for applying
A substrate processing apparatus having a mechanism for removing a substrate after depressurization.