JPH10172923A - Forming mehtod for metallic wiring for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the formation of grooves in wiring metal, by heat-treating a metal film deposited at a low temperature on a semiconductor substrate at a hot temperature lower than its melting point, and keeping the semiconductor substrate at a temperature higher than this temperature for a specified length of time after that in addition. SOLUTION: Metal is deposited on the surface of an insulating film 42, the internal surface of a contact hole C, and the exposed surface of a silicon substrate 40, and a metal film 44 is formed. Next, the silicon substrate is transferred to a flow chamber, and the atmosphere in the chamber is made into a ultra-high vacuum state. After that, the temperature in the chamber is set to a temperature 0.7T-0.9T (T is the melting point of the metal constituting the metal film), and heat treatment is performed and a metal flow is generated. And distribution metal wires 44' filling up contact holes C formed. Next, the silicon substrate having the distributing metal wires 44' is transferred to another flow chamber. And heat treatment is performed by making the atmosphere in the chamber in a ultra-high vacuum state, and setting the temperature in the chamber higher that the preceding high temperature by about 0.05T-0.2T.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a metal wiring of a semiconductor device, and more particularly, to an aspect ratio (Aspect) of a contact hole.
The present invention relates to a method for forming a metal wiring of a ULSI-class semiconductor device, which has a large ratio and needs to apply an aluminum flowing step.

[0002]

2. Description of the Related Art Recently, as semiconductor integrated circuits are miniaturized and multilayered, contact holes for electrical connection of elements are not only miniaturized to 0.5 μm or less, but also insulating films are formed. As a result, the depth of the contact hole also increases to 1 μm or more, and the aspect ratio of the contact hole suddenly increases to 2 or more. Thereby, the existing physical vapor deposition (Physic)
al Vapor Deposition (PVD)
When a wiring metal, for example, an aluminum alloy is deposited by applying a technique such as sputtering, the step coverage in the contact hole (Steeling) is increased.
p Coverage: the deposition thickness of the stepped surface / the deposition thickness of the smooth surface) deteriorates to 10% or less, and the electron transfer (Elect)
(EM) or stress transfer (Stre
The disconnection of the wiring due to ss-migration (SM) or the like occurs.

Here, the electron transfer is a phenomenon in which aluminum atoms move in the flow direction of electrons when a current flows through the wiring to cause a defect in the wiring. Voi
d) Generation and whiskers (Wh) on which aluminum is accumulated
isker) There are two forms of growth. On the other hand, stress transfer failure is a phenomenon in which wiring is disconnected when left at a temperature of about 100 ° C. or more even when current does not flow through the wiring, due to a large thermal expansion coefficient difference between aluminum as the wiring and the insulating film that insulates the wiring. The resulting stress acts on its main cause. As a form in which a defect occurs, a slit (Sli
There is a form in which the aluminum wiring is defective in the t) shape, and a void form in which aluminum (Aluminium) is lost and the wall side portion of the wiring has a V-shaped wedge shape.

Accordingly, in order to improve the step coverage of the contact hole C, chemical vapor deposition (Chemical Vapor Deposition) is performed.
Researches applying a Pour Deposition (CVD) technique are ongoing. A typical example is a technique that has already been put into practical use. Tungsten is deposited on a substrate on which a contact hole is formed, and etched back (Etch Back) to a thickness greater than the deposition thickness to form a tungsten plug in the contact hole. (Tungst
en Plug) and a technique for selectively growing tungsten only in the contact hole. Also, recently, studies have been actively conducted to form a contact plug and a wiring layer using the same material, for example, a material such as aluminum by using chemical vapor deposition to improve the reliability of a semiconductor device. Have been. However, such a chemical vapor deposition technology. Since the manufacturing cost is high and the technology has not been mass-produced, the step problem is solved at present using aluminum vapor deposition technology which is inexpensive and has a high degree of perfection in comparison with chemical vapor deposition technology.

The aluminum flowing (Alum)
(inium FIowing) technology is a slightly modified wiring formation process using existing sputtering.
Aluminum, which is a wiring metal, is vapor-deposited on a substrate by a sputtering method as in the conventional method, and then heat-treated at a high temperature (for example, 500 ° C. to 650 ° C.) or lower, which is equal to or lower than the melting point of aluminum. To improve the level difference by flowing aluminum into the lower part of the contact hole.

FIGS. 3A to 3C are process flow charts showing a conventional method for forming a metal wiring of a semiconductor device using this aluminum flowing technique. A conventional method for forming a metal wiring will be briefly described with reference to the above process sequence diagram. First, as shown in FIG. An oxide film serving as an insulating film 3 is deposited on a semiconductor substrate, for example, a silicon substrate 1, and a semiconductor device formed on the silicon substrate 1 is connected to a wiring metal for transmitting a signal to the semiconductor device. A portion of the insulating film is etched to form a contact hole C.

Next, in order to sputter a wiring metal (for example, aluminum or an aluminum alloy) on the surface of the silicon substrate 1 where the contact hole C is formed, the silicon substrate 1 is loaded into a sputtering equipment. After that, it is connected to a degassing chamber (Degassing Ch) in the equipment.
a), and a degassing step of heating the silicon substrate 1 in a vacuum state is performed. The reason why the degassing step is performed is to improve the fluidity of metal particles in the contact hole C when sputtering metal used as wiring. The above process affects the groove formation (grooving) of the subsequently deposited metal film.

Next, in order to form a metal wiring, FIG.
As shown in FIG. 1, a silicon substrate 1 in which a contact hole C is formed is placed in a sputtering chamber (Sputte).
(Chamber) to form an atmosphere in the chamber in an ultra-high vacuum state, and then sputter a wiring metal to deposit a metal film 5 on the insulating film 3 including the contact hole C at a low temperature of 150 ° C. or less. Let it. The metal film 5 thus formed has a grain size of aluminum (Gra).
in Size) and aluminum grain (A)
Luminium Grain has a large surface free energy.

Next, as shown in FIG. 3C, the silicon substrate 1 on which the metal film 5 has been deposited is transferred to a flow chamber, and the atmosphere in the chamber is set in an ultra-high vacuum state. (For example, 10e-7t
After forming the chamber at a degree of vacuum of about orr), a heat treatment step is performed in which the temperature in the chamber is set to a temperature at which a flow can be generated, and then heating is performed for a certain time. The temperature range used during the heat treatment is about 70% to 90% of the melting point of aluminum forming the metal film 5. In this process, a flow phenomenon occurs in which the aluminum particles of the metal film 5 move from a high free energy to a low free energy, and the deposited metal film 5 flows into the contact hole C. Therefore, as shown in the figure, a metal wiring 5 ′ in which the metal film 5 fills the contact hole C is formed.

Next, after the silicon substrate 1 on which the metal wiring 5 'is formed is cooled in a cooling chamber through a transfer chamber, a subsequent semiconductor manufacturing process is executed to complete the present process.
The cooling step greatly affects the formation of the aluminum crystal grain boundaries and grooves forming the metal wiring 5 ', and is usually performed by one of the following two methods. One is the silicon substrate 1 on which the wiring 5 'is formed.
Is taken out of the flow chamber and allowed to cool naturally by leaving it in a vacuum before the step of executing the manufacturing process of the subsequent semiconductor element.
Is transferred to a cooling chamber again, and then cooled by injecting a cold gas (for example, argon gas (Argon Gas)) into the chamber.

FIG. 4 shows a temperature profile between a flow chamber, a transfer chamber, and a cooling chamber when a metal wiring of a semiconductor device is formed through the above process.
A graph showing e) is shown. As shown in the figure, when a metal film is deposited at a low temperature of 150 ° C. or less and then subjected to a high-temperature (several hundred degrees C.) heat treatment in a flow chamber to reflow particles of the metal film to form a metal wiring, When the metal wiring passes through the transfer chamber, the temperature is lowered by a predetermined range (Down), and when the metal wiring is transferred to the cooling chamber in a lowered state, the temperature is lowered to a lower temperature through the cooling process in the cooling chamber. As a method, a thick gold film on a semiconductor substrate is cooled.

When the wiring of the semiconductor device is formed by the above-described method by applying the aluminum flowing process, the step coverage in a sub-micron and a narrow contact is reduced.
Although it can be improved to some extent, the following two problems occur during the process. 1. After the wiring metal is deposited by the sputtering method, this is heat-treated at a high temperature below the melting point to reflow the metal particles (Reflow).
During the process, the grain boundary of aluminum forming the metal wiring is increased to several microns, so that the groove at the triple point where the grain boundaries contact each other increases. As a result, there is a problem that the reliability of the wiring is reduced. The groove directly connected to the reliability of the metal wiring is generated due to interfacial tension.
The ia is larger than when cooling from a high temperature to a low temperature rapidly, so that a faster cooling process performed after the heat treatment process in the flow chamber further increases the size of the aluminum groove forming the metal wiring 5 ′.

FIGS. 5A and 5B are schematic views of aluminum particles for explaining such a phenomenon of groove formation. In the drawings, reference numeral 10 denotes a silicon substrate, reference numeral 12 denotes a metal film made of aluminum or an aluminum alloy, and reference numerals Ga,
Gb, Gb ′, Gc, Gc ′ indicate particles constituting the metal film 12. When the heat treatment of the metal film 12 made of aluminum or an aluminum alloy is repeatedly performed at low and high temperatures, dislocation slips (Disloc) are formed inside the grains.
At this time, particles forming the metal film 12 are subjected to stress relaxation (Stress Rel).
axation) to rotate particles (Grain Ro)
Tation) occurs.

This will be described in detail with reference to FIGS. 5A and 5B. Generally, when a metal film 12 made of aluminum or an aluminum alloy is formed on a substrate 10 by a sputtering method, the metal film 12 has a very strong fibrous structure having a <111> orientation. Among them, some particles, that is, Gb, have a <111> plane that is not completely parallel to the surface of the aluminum or aluminum alloy film, and as shown in FIG. When the metal film 12 that is present at an angle and has the above-described fine structure undergoes a heat treatment process, the particles Gb rotate so as to have a <111> orientation parallel to the film surface.

FIG. 5B shows the arrangement of particles after the metal film 12 of FIG. 5A has undergone a heat treatment step. Here, the particle Gb ′ is <1 due to the rotation of the particle Gb in FIG.
11> indicates that the particles were changed to particles having orientation. When such large particles rotate, the flatness of the film surface and the formation of grooves become intense, and during cooling, the tensile strain (Te
Plastic change (Plas) due to nsile strain
The tic deformation makes this groove shear larger. Such a phenomenon is illustrated by reference numerals 14 and 14 'in the drawings.

When the groove is enlarged, when patterning a metal made of aluminum or an aluminum alloy, a chemical penetrates into a boundary portion of the aluminum particles through the groove to induce corrosive pitting. In addition to this, the metal is fragile to stress and breaks in the subsequent heat treatment, or a compound (for example, Si-Cu used in an aluminum alloy) precipitates at the triple point, and metal for forming wiring is formed. During the patterning operation, since the metal is not completely removed and the Si-Cu compound remains, unnecessary bridges between metal lines (Bridg) are thereafter required.
e) to form a short (L
in short). Therefore, when a barrier metal film made of TiN is deposited on the metal film on which the groove is formed, TiN is sufficiently deposited on a portion where the groove is formed, and a deposition failure phenomenon occurs.

FIG. 6 shows that a Ti film is formed on a metal film having a large groove.
A perspective view showing a film deposition state when a barrier metal film made of N is formed is shown. In the drawings, reference numeral 20 denotes a metal film made of an aluminum alloy, reference numeral 22 denotes a barrier metal (barrier metal) film made of TiN, and reference numerals G1, G2, and G3 denote the metal film 20.
And reference numeral 24 denotes the particle G1,
Reference numeral 26 denotes a groove formed between G2 and G3, and reference numeral 26 denotes a defective portion in the form of a slit formed on the barrier metal film 22.

As shown in the figure, when a barrier metal is deposited on a metal wiring manufactured by applying an aluminum flowing technique, a poor deposition phenomenon occurs at a portion where a groove is formed violently, and a barrier metal film 22 is formed. Are arranged in the form of a slit. Due to such a phenomenon, when the photosensitive film is developed in the post-process, the metal film 22 is easily exposed to the chemical, so that corrosive pitting occurs. When the post-residue remains, a line short of the wiring line is induced.

2. If the aspect ratio does not exceed 1 even when the aluminum flowing technique is applied, the void (Voi) shown in FIG. 3C is used without exception.
d) There is a problem that V is generated and the reliability of the metal wiring is reduced. Recently, as a method of improving the reliability of wiring, an improved sputtering apparatus in which a collimator is attached to a conventional sputtering apparatus in order to eliminate such voids and improve the problem of a step difference. Research on vapor deposition of wiring metal using GaN has been actively conducted.

FIG. 7 is a schematic diagram showing a sectional structure of a sputtering apparatus provided with a collimator developed for such a purpose. As shown,
In the sputtering apparatus, the positive electrode 32 on which the semiconductor substrate 30 is located and the negative electrode 36 on which the metal target (Target) 34 is mounted are opposed to each other. A collimator 38 made of a net-like conductor made of a regular hexagon is mounted on the base plate. At this time, the semiconductor substrate 30 positioned on the positive electrode 32 has a contact hole C formed as shown in FIG. 3A, and the metal target 34 used here is aluminum. Or aluminum alloy target.

Therefore, the sputtering apparatus comprises:
Aluminum or an aluminum alloy, which is a wiring metal, is deposited on the contact holes on the substrate 30 by the following method. That is, the plasma (Plas) colliding at high speed
When the metal target particles are sputtered on the semiconductor substrate 30 by colliding with a ma (for example, Ar ion), aluminum or aluminum alloy particles incident at a free angle that collide with the collimator 38 are filtered. Only the particles that travel straight without collision pass through, and the particles that have passed through the collimator 38 are deposited on the surface of the contact hole C on the semiconductor substrate 30. The collimator sputtering method is such that the material of the metal target is sputtered on the surface of the contact hole C by such a principle.

When the wiring metal is vapor-deposited by such a collimator method, an existing sputtering process is performed, as shown in FIG.
As shown in FIG.
g) The step defect problem caused by the portion H obstructing the target particles arriving at the bottom of the contact hole C (the shadow effect (Shadow Effect))
) Can be minimized.

[0023]

However, the conventional techniques as described above have the following problems when used.
This will be described with reference to the schematic diagram shown in FIG. In the schematic diagram, the specific form of the aluminum or aluminum alloy particles P1 passing through the collimator 38 of the sputtering apparatus shown in FIG. 7 is enlarged. That is, among the aluminum or aluminum alloy particles sputtered from the metal target (Target) 34, the particles P1 arriving in an arbitrary direction that is not perpendicular to the collimator 38 cannot pass through the collimator 38, and the schematic diagram shown in FIG. The slit size (Slit) of the collimator 38 is attached to the collimator 38 like the P2 portion.
Size) decreases.

As a result, the amount of the particles P1 that reach the bottom of the contact hole C of the semiconductor substrate 30 without colliding with the collimator 38 is reduced, so that the deposition rate is reduced. Problems such as a decrease in reproducibility occur. The problem of such a decrease in the deposition rate becomes more severe as the number of depositions increases, and in particular, particles (P) generated when particles adhered to the collimator 38 fall again to the substrate side.
The problem of the article acts as a main factor that causes a film quality defect, and causes serious damage to the semiconductor device.

In order for such a collimator sputtering technique to play a role as a technique having mass productivity,
Much research and development for solving the various problems as described above needs to be performed in advance. Therefore, an object of the present invention is to reduce the occurrence of groove formation in a wiring metal by changing the flow temperature when a metal film deposited at a low temperature is heat-treated at a high temperature below the melting point and reflowed. It is an object of the present invention to provide a method for forming a metal wiring of a semiconductor device with improved reliability.

[0026]

According to a feature of the present invention to achieve the above object, a step of depositing a metal film on a semiconductor substrate at a low temperature and a step of heat-treating the metal film at a high temperature below the melting point. Reflowing the particles of the metal film by
An ultra-high-temperature heat treatment step of maintaining the semiconductor substrate at a temperature higher than the temperature used during the high-temperature heat treatment for a certain period of time and preventing the formation of grooves between particles of the metal film is provided. At this time, the low temperature is 150
° C or lower is preferable, and the high temperature is 0.7 T or more.
A temperature in the range of 0.9T (T is the melting point of the metal constituting the metal film) is preferable. The ultra-high temperature has a temperature of T (T is a melting point of a metal constituting the metal film) or less and is about 0.05 to 0.2 T higher than the high temperature.
A temperature about T higher is preferred. The initial high-temperature heat treatment is performed in a range of 20 seconds to 60 seconds.

Further, according to the present invention, after the ultra-high temperature heat treatment step, before performing a subsequent semiconductor device manufacturing process,
Preferably, the metal film on the semiconductor substrate is slowly cooled using a heating tool, wherein the cooling is advanced so as to lower the heating temperature at a temperature of less than 1 to 2 degrees per second, and the metal film is cooled to a temperature of 0.1 to 2 degrees. It is cooled to a temperature in the range of 5T to 0.8T (T is the melting point of the metal constituting the metal film). At this time, the ultra high temperature heat treatment step may be performed while maintaining a vacuum state in the flow chamber where the high temperature heat treatment is performed, and has the same vacuum as the flow chamber where the high temperature heat treatment is performed. The process can be performed using other flow chambers.

In the present invention, the metal film may be formed using aluminum or an aluminum alloy, and is preferably formed using an aluminum alloy having a Si content of 0.5% or less. When the metal wiring is formed by changing the flow temperature as described above, not only the formation of crystal grain boundaries and grooves of the metal film particles forming the wiring can be reduced, but also the generation of voids can be eliminated.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG.
1A to 1C are process flowcharts showing a method for forming a metal wiring of a semiconductor device according to the present invention to which an aluminum flowing technique is applied. The drawings showing the shapes of the metal film particles constituting the metal film in each process step and the state of the formation of the grooves at this time are both presented in the process sequence diagram. A conventional method for forming a metal wiring will be described below with reference to the above-mentioned process sequence diagram.

FIG. 1A shows a metal film 44 made of aluminum or an aluminum alloy on a semiconductor substrate in which a contact hole is formed, for example, a silicon substrate 40.
Is shown. More specifically, first, an insulating film 42 is formed on a silicon substrate 40 on which an impurity doping (Doping) region (not shown) is formed.
Is formed to a thickness of 0.8 μm to 1.6 μm, and the insulating film 42 is etched so that a predetermined portion of the surface of the silicon substrate 40 is exposed to form a contact hole C. At this time, the size of the opening of the contact hole C is 0.5 μm to 1.0 μm (diameter or width).

Next, a metal is deposited at a low temperature on the surface of the insulating film 42, the inner surface of the contact hole C, and the exposed surface of the silicon substrate 40 to form a metal film 44 having a thickness of 600 nm.
To form The metal film 44 is made of Cu,
Aluminum alloy containing one or more elements such as Si and Ge (for example, A1-Cu, A1-Si-Cu, A
1-Ge or the like, and preferably, an aluminum alloy containing 0.5% or less of Si (for example, A1-S
i (0.2%)-Cu (0.5%)).

At this time, the metal is deposited at a low temperature of 150 ° C. or less and in a Ar atmosphere of 4 mTorr or less by a sputtering method at a rate of 10 nm / sec to 15 nm / sec. The lower the temperature of the metal deposition, the higher the surface free energy and the better the reflow characteristics. Therefore,
Advantageously, the metal is deposited as low as possible, preferably at room temperature. The metal film 44 thus formed is characterized in that the metal particles (for example, aluminum) constituting the metal film have a small crystal grain size and a large surface free energy of the metal particles.
FIG. 1A-1 shows the shape of the metal particles corresponding to the portion D of the metal film having the above-described characteristics.
FIG. 1A-2 shows a groove formed on the surface of the metal film 44 composed of the metal particles as described above.

FIG. 1B shows a step of filling the contact hole C with the metal of the metal film 44 through a high-temperature heat treatment in a flow chamber. To explain this concretely,
First, as shown in FIG.
After the metal film 44 is formed on the silicon substrate 40,
Is transferred to a flow chamber while maintaining a vacuum state, and the atmosphere in the chamber is changed to an ultra-high vacuum state (for example, 10e).
-7 torr), and after setting the temperature in the chamber to a temperature at which a flow can be generated,
The heat treatment is performed for about 40 seconds or more, preferably for 1 minute and 30 seconds. The temperature of the chamber used during the heat treatment is 0.7 T
０．９0.9T (T is the melting point of the metal constituting the metal film).

In this process, a flow phenomenon occurs in which the aluminum particles of the metal film 44 move from a place where the free energy is high to a place where the free energy is low, and the metal of the deposited metal film 44 flows into the contact hole C. As a result, the contact hole C is buried. As a result, as shown in the figure, a metal wiring 44 'in which the metal film fills the contact hole C is formed. However, when the aspect ratio of the contact hole C is 1 or more, a void (not shown) exists in the wiring 44 'as in the related art. At this time, since the energy of the metal wiring 44 'was consumed in the process of filling the contact hole C with the metal forming the metal film 44, the surface of the metal particles was smaller than that of the metal film 44 of FIG. The energy is small, and the crystal grain size of the metal particles (for example, aluminum) constituting the metal film has a feature that the crystal grain size of the metal particle is increased. It is because it increased.

FIG. 1 (B-1) shows the shape of the metal particles corresponding to the portion D1 of the metal wiring having the above characteristics, and FIG. 1 (B-2) shows the shape of the metal particles. The shape of a groove formed on the surface of a metal film composed of metal particles is illustrated. Further, as shown in the figure, the groove of the metal film forming the metal wiring 44 'is larger than that in FIG.

FIG. 1C shows a step of removing voids in the metal film forming the metal wiring 44 "through an ultra-high temperature heat treatment.
When the high-temperature heat treatment step (B) is completed, the silicon substrate 40 on which the metal wiring 44 'is formed is transferred to another flow chamber while maintaining a vacuum state, and the atmosphere in the chamber is increased to an extremely high level. Vacuum state (for example, 10e-7tor)
r), the temperature in the chamber is set to be higher than the high temperature by about 0.05T to 0.2T (T is the melting point of the metal constituting the metal film). A heat treatment step is performed.

At this time, the ultrahigh temperature is higher than the high temperature, but the variable range of the temperature is set to have a value of T (T is the melting point of the metal constituting the metal film) or less,
The ultra high temperature heat treatment may be performed in the flow chamber used in the high temperature heat treatment without moving the flow chamber. The gold layer wiring 44 ″ thus heat-treated at an ultra-high temperature.
Is characterized in that the crystal grain size of metal particles (for example, aluminum) is larger than that of the metal wiring 44 'shown in FIG.
Further, this process has a feature that voids not removed in the high-temperature heat treatment step can be removed.

FIG. 1 (C-1) shows the shape of the metal particles corresponding to the portion D2 of the metal wiring having the above characteristics, and FIG. 1 (C-2) shows the shape of the metal particles. The shape of the groove formed on the surface of the metal film composed of such metal particles is illustrated. 7, the formation of grooves in the metal film constituting the metal wiring 44 ″ is slower than in FIG.
The silicon substrate 40 on which 4 ″ has been formed is made of Teflon (Teflon).
lon), the silicon substrate 40 is housed in a cooling chamber, and the metal film forming the metal wiring is placed on a carrier cassette (Carrier: also referred to as wafer cassette).
It is cooled to a temperature of T to 0.8T (T is the melting point of the metal constituting the metal film). At this time, the cooling process is performed by using a heating device to slowly lower the heating temperature at a temperature of less than 1 to 2 degrees per second.

As described above, when the cooling is performed slowly, the state in which the formation of the grooves is suppressed can be maintained, and as a result, a metal film having a smooth surface can be formed, and the progress of the post-process can be facilitated. When the barrier metal film is formed, the step coverage of the barrier metal film can be improved, and the chemical resistance and corrosion resistance of the metal film are improved.

FIG. 2 shows the temperature between the flow chamber and the cooling chamber when the metal wiring of the semiconductor device is formed by applying the aluminum flowing process configured to change the temperature as described above. A graph showing the profile is shown. The graph shows the case where the process is performed using another flow chamber in each of the high-temperature heat treatment step and the ultra-high-temperature heat treatment step. The cooling step is divided into a third step, and a chamber used during the high temperature heat treatment is referred to as a first flow chamber, and a flow chamber used during the ultra high temperature heat treatment is referred to as a second flow chamber. As shown in the graph, according to the present invention, a metal wire of a semiconductor device is formed by reflowing metal particles constituting a metal film through a first step of a high temperature heat treatment step and a second step of an ultra high temperature heat treatment step. To suppress the generation of grooves.

[0041]

As described above, according to the present invention, the occurrence of grooves can be suppressed by changing the temperature during the aluminum flowing step, so that the subsequent steps can be carried out more easily and the resistance of the metal wiring can be reduced. It is possible to form a highly reliable metal wiring in which the chemical property and the corrosion resistance are improved and the generation of voids in a highly integrated device having an aspect ratio of 1 or more is suppressed.

[Brief description of the drawings]

FIG. 1 is a process flow chart showing a method for forming a metal wiring of a semiconductor device shown as an embodiment of the present invention.

FIG. 2 is a graph showing a temperature profile of the semiconductor device shown as an embodiment of the present invention when the semiconductor device passes through a flow chamber and a cooling chamber during metal wiring.

FIG. 3 is a process flowchart showing a method of forming a metal wiring of a semiconductor device according to a conventional technique.

FIG. 4 is a graph showing a temperature profile during a process of passing through a flow chamber and a cooling chamber when forming a metal wiring of a semiconductor device according to the related art.

FIG. 5 is a schematic view showing a structure of aluminum particles for explaining generation of a groove.

FIG. 6 is a perspective view illustrating a film deposition state when a barrier metal film is formed on a metal film in which a groove is generated.

FIG. 7 is a schematic diagram illustrating a cross-sectional structure of a sputtering apparatus provided with a conventional collimator.

FIG. 8 is an enlarged schematic view illustrating a shape of a metal particle passing through a collimator of the sputtering apparatus of FIG. 7;

[Explanation of symbols]

 1, 10, 40: silicon substrate 3, 42: insulating film 5, 12, 20, 44: metal film 5'44 ': metal wiring 22: barrier metal film 30: semiconductor substrate 32: anode electrode 34: metal target 36: Cathode electrode 38: Collimator C: Contact hole

Claims (19)

[Claims] 1. a step of depositing a metal film on a semiconductor substrate at a low temperature; a step of heat-treating the metal film at a high temperature below a melting point to reflow particles of the metal film; An ultra-high temperature heat treatment step of maintaining the semiconductor substrate at a temperature higher than the temperature for a certain period of time to prevent formation of grooves between particles of the metal film. 2. The method of claim 1, further comprising, after the step of performing the ultra-high temperature heat treatment and before performing a process of manufacturing a subsequent semiconductor device, slowly cooling the metal film on the semiconductor substrate using a heating tool. A method for forming a metal wiring of a semiconductor device according to claim 1. 3. The method according to claim 2, wherein the cooling step is performed by gradually lowering a heating temperature at a temperature of less than 1 to 2 degrees per second. . 4. The method according to claim 1, wherein the metal film has a thickness of 0.5T to 0.8T (T
3. The method according to claim 2, wherein the metal film is cooled to a temperature within a range of the melting point of the metal constituting the metal film. 5. The method according to claim 1, wherein the low temperature is a temperature between room temperature and 150 ° C. or less. 6. The semiconductor according to claim 1, wherein the bulk temperature is a temperature in a range of 0.7T to 0.9T (T is a melting point of a metal constituting the metal film). A method for forming a metal wiring of an element. 7. An ultra-high temperature at which the ultra-high temperature heat treatment is used has a temperature equal to or lower than T (T is a melting point of a metal constituting the metal film), and is 0.05% lower than the high temperature.
7. The method according to claim 1, wherein the temperature is higher in a range of T to 0.2T. 8. The ultra-high-temperature heat treatment step may be performed for 20 seconds to 60 seconds.
2. The method according to claim 1, wherein the method is performed for seconds. 9. The method of claim 1, wherein the metal film is formed of an aluminum alloy having a Si content of 0.5% or less. 10. The method of claim 1, wherein the step of performing the ultra-high temperature heat treatment is performed while maintaining a vacuum state in the flow chamber in which the high temperature heat treatment has been performed. 11. The metal of claim 1, wherein the ultra-high temperature heat treatment is performed in another flow chamber having the same vacuum as the flow chamber in which the high temperature heat treatment was performed. Wiring formation method. 12. A step of depositing a metal film on a semiconductor substrate at a low temperature of 150 ° C. or less; and 0.7T to 0.9T (T is a melting point of a metal constituting the metal film). Heat-treating the metal film particles at a high temperature in the range of: re-flowing the metal film particles at a temperature higher than the high temperature for a predetermined time; and cooling the metal film slowly using a heating device. A method of forming a metal wiring of a semiconductor device. 13. The ultra-high temperature has a temperature equal to or lower than T (T is a melting point of a metal constituting the metal film), and is higher than the high temperature by about 0.05 T to 0.2 T. 13. The method according to claim 12, wherein: 14. The method of claim 12, wherein the ultra-high temperature heat treatment is performed for 20 seconds to 60 seconds. 15. The method of claim 12, wherein the heating device is designed to lower a heating temperature at a temperature of less than 1 to 2 degrees per second. 16. The metal film may have a thickness of 0.5T to 0.8T.
13. The method according to claim 12, wherein cooling is performed to a temperature in a range of (T is a melting point of a metal forming the metal film). 17. The metal film according to claim 1, wherein a content of Si is 0.5%.
13. The method for forming a metal wiring of a semiconductor device according to claim 12, wherein the metal wiring is formed of the following aluminum alloy. 18. The method of claim 12, wherein the ultra-high temperature heat treatment is performed while maintaining a vacuum state in the flow chamber in which the high temperature heat treatment has been performed. 19. The metal of claim 12, wherein the ultra-high temperature heat treatment is performed in another flow chamber having the same degree of vacuum as the flow chamber in which the high temperature heat treatment was performed. Wiring formation method.