JPH1041383A - Manufacture of semiconductor device and film formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase anti-electromigration property of an interconnect layer of a semiconductor device and increase patterning accuracy of wiring. SOLUTION: By boiling (15 minutes to 3 hours) a substrate in pure water, a moisture absorption layer is formed on the surface of a BPSG(borophosphor silicate glass) film 13. After that, a contact hole 12 is formed in the BPSG film 13 and then an TI film 14, TiN films 15, 16, and a TI film 17 are deposited in this order on the BPSG film 13 and the contact hole 12. Nextly, an Al alloy film 18 is deposited on the Ti film 17 by high-temperature sputtering. As for another method for manufacturing, the contact hole 12 is formed in the BPSG film 13 without boiling the substrate and then water is introduced when depositing the Ti film 14 or depositing the Ti film 14 and the TiN film 15 and the partial pressure of H2 O in a chamber of the film formation device is controlled to 1×10<-8> -1×10<-7> Torr. By this method, the (111) orientation of the Al alloy film as an interconnection layer can be made high and the surface smoothness can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a semiconductor device, and more particularly to a structure of a metal wiring portion and an apparatus for forming a film such as the wiring portion.

[0002]

2. Description of the Related Art In recent years, along with the high integration of VLSI, miniaturization of dimensions of elements and wirings in a plane direction (horizontal direction) has been advanced. It has not progressed compared to the miniaturization in the horizontal direction. Therefore, as the element becomes finer, the diameter of the connection hole (contact hole) provided in the interlayer insulating film for connecting the wiring and the element becomes smaller, but the thickness of the interlayer insulating film does not become thinner. Aspect ratio (ratio of connection hole depth to connection hole diameter)
Have to grow. For this reason, in the usual sputtering method (sputtering method performed at a substrate temperature of 300 ° C. or less), in the connection hole portion,
It has become difficult to ensure sufficient step coverage of the wiring material.

In order to improve the step coverage of the wiring material, various methods for filling the wiring material into the contact holes have been proposed in recent years. W (tungsten) or Al (aluminum) as a conductive material for embedding
Such alloys are widely known, and among them, a film forming technique using a high-temperature sputtering method for an Al alloy is known. This high-temperature sputtering method is a method in which a substrate is heated to about 500 ° C. during sputtering to cause the surface of the Al alloy adhered to the substrate to flow by heat, thereby embedding the Al alloy in fine contact holes.

A semiconductor device formed by this method is
For example, it has a configuration as shown in FIG. First, on the semiconductor substrate 41, a BPSG (Boro
phosphosilicate glass) film 43 is formed, and this BP
A contact hole 42 is formed in the SG film 43. Prior to embedding the Al alloy film 47 in the contact hole 42 by a high-temperature sputtering method, a base layer is formed on the surface of the contact hole 42 and the BPSG film 43.

The underlying layer is composed of a Ti film 44 / Ti
N film 45 or Ti film 44 / TiN film 45 / Ti film 4
6 is known. And
These underlayers generally have a substrate temperature of 150-3.
It is formed by sputtering at 50 ° C.

Here, the above-mentioned first layer Ti film 44 is
Semiconductor substrate 41 exposed at the bottom of contact hole 42
Reacts with Si atoms to form silicide (TiSi ₂ ) and plays a role as a contact metal for stabilizing contact resistance. Second layer TiN film 45
Is that the Al of the Al alloy film 47, which is the wiring layer formed thereon by high-temperature sputtering, is changed to the lower semiconductor substrate 41.
It plays a role as a barrier layer that prevents diffusion to Although not necessarily a commonly used layer, the third layer Ti film 46 is formed for the purpose of improving the film quality of the Al alloy film 47. Further, the Al alloy film 4
7 has good wettability to the Al alloy film 47, so that the Ti film 46 or the TiN film 45 immediately below
The alloy has a function of facilitating the flow of the alloy into the contact hole 42 and allowing the hole to be buried.
As described above, the underlying layer generally provided between the interlayer insulating film 43 and the wiring layer 47 plays an important role in filling the contact hole 12 by the above-described high-temperature sputtering, and is an essential element. .

[0007]

The current density of the wiring layer used in the VLSI has been increased due to the reduction in the wiring width. Therefore, the wiring is required to have high electromigration resistance. Further, in order to form fine wiring, high patterning accuracy is required.

Here, the electromigration resistance of the Al wiring (Al alloy wiring) strongly depends on the film quality of the Al alloy film. 111)
The orientation must be high. This is because, if the orientations of the crystal grains of the Al alloy film are not aligned, the disorder of the atomic arrangement at the crystal grain boundaries becomes strong, and Al atoms easily move along the crystal grain boundaries due to electric current. Therefore, it is necessary to align the <111> orientation direction of the crystal in each crystal grain.

On the other hand, in order to pattern wiring with high accuracy, the wiring film surface must be smooth so that halation does not occur due to irregular reflection of light on the wiring film surface during a resist exposure step in a photolithography step. Required.

However, the high temperature sputtered Al alloy film according to the prior art does not satisfy these requirements. The reason is that the conventional high-temperature sputtered Al alloy film
As shown in <11>, <111> of each crystal grain of the Al alloy film 47
The direction (in the figure, the <111> direction of Al is indicated by an arrow)
It is not necessarily formed so as to be oriented perpendicular to the surface of the Si substrate. If the <111> directions of the crystal grains are not aligned as described above, the surface irregularities will increase. A wiring obtained by patterning a film having many surface irregularities has a nonuniform film thickness and a nonuniform wiring line width due to the occurrence of the above-mentioned halation.

As described above, the conventional high-temperature sputtered Al alloy wiring has a low (111) orientation of crystal grains, a nonuniform film thickness due to surface irregularities, and a variation in wiring width. For this reason, there is a problem that it is difficult to obtain a wiring layer having high electromigration resistance.

Accordingly, an object of the present invention is to provide a semiconductor device having a high orientation of crystal grains of a wiring layer and a high smoothness of a wiring surface, and a film forming method for manufacturing such a semiconductor device. It is intended to provide a device.

[0013]

Means for Solving the Problems The present invention has been made to achieve the above object, and has an interlayer insulating film formed on a substrate, a titanium film formed on the interlayer insulating film, and titanium nitride on the titanium film. A semiconductor device having a film and an aluminum wiring layer on a titanium nitride film, wherein the semiconductor device is formed of a gaseous or liquid H ₂ O before or during the formation of a titanium film or a titanium film and a titanium nitride film. It is characterized by exposure to an atmosphere.

In a film forming apparatus capable of forming a film of a titanium-based material such as a titanium film or a titanium nitride film, when these titanium films, or a titanium film and a titanium nitride film are formed, H _{2 is} contained in a film forming chamber. It is characterized in that O can be introduced.

[Background of the Invention] It is generally known that the crystal orientation of a conductive material such as Al used as a wiring layer is closely related to the crystal orientation of an underlayer. The underlayer often has a structure in which a contact metal / barrier metal is sequentially stacked from the lower layer. Where, for example,
When Ti / TiN / Ti is formed in order from the lower layer, the higher the (002) orientation of the first Ti film, the higher the (111) orientation of the second TiN film and the higher the (111) orientation. The (002) orientation of the layer Ti film is increased. Furthermore, when an Al alloy film is formed as a wiring layer on such a third-layer Ti film, the (111) orientation of Al crystals in the wiring layer is increased. This is because the atomic arrangements of the (002) plane of the Ti film, the (111) plane of the TiN film, and the (111) plane of the Al layer are similar to each other.
This is because the orientation is inherited by the upper layer by epitaxial growth. Therefore, in order to obtain an Al alloy film having a high (111) orientation, it is important to form a first-layer Ti film having a high (002) orientation.

On the other hand, the crystal orientation of the first-layer Ti film, which is the lowermost layer, is determined by the underlying insulating film, for example, BPSG.
It is considered that the film thickness strongly depends on the surface condition of the film, the SiO ₂ film, the PSG film, and the like and the conditions for forming the first Ti film. Therefore, the present inventor has proposed a BPSG film surface state and a first state.
Various studies were conducted on the influence of the film forming conditions of the layer Ti film on the crystal orientation of the Ti film. As a result of this research, the (002) orientation of the first-layer Ti film is stronger than the amount of water absorbed on the surface of the interlayer insulating film or the amount of water in the chamber during Ti film formation. The inventors have found that they have dependency, and have led to the present invention.

Specifically, the present invention has been obtained by the following experiments and considerations.

(1) An interlayer insulating film (here, a BPSG film) formed on a substrate made of silicon or the like is formed at a temperature of 23 ° C.
It is left in the atmosphere maintained at a humidity of 60% for several tens of minutes to several hundred hours, and then a Ti film is formed on the BPSG film by sputtering at a substrate temperature of 350 ° C. Examination of the crystal orientation of the formed Ti film revealed that the (002) orientation was improved as the Ti film was formed on the BPSG film having a longer standing time in the air.

(2) BPSG formed on a substrate
After boiling the film in pure water at 95 to 100 ° C. for several minutes to 1 hour, a Ti film was formed on the BPSG film, and the crystal orientation of the Ti film was examined. As a result, up to the boiling time of 1 hour, as the boiling time becomes longer, the T formed on the BPSG film becomes longer.
It became clear that the (002) orientation of the i film was improved. Further, the Ti film on the BPSG film which was boiled at 95 ° C. for 1 hour is almost the same as the Ti film formed on the surface of the BPSG film which was left in the atmosphere at a temperature of 23 ° C. and a humidity of 60% for 400 hours. (002) orientation.

Here, (0) of the Ti film is
02) The reason why the orientation is improved will be considered. First,
It is generally known that the BPSG film, which is an insulating film, has a property of absorbing moisture. Then, the moisture absorption rate of the BPSG film is accelerated as the water concentration and the temperature in the atmosphere to which the BPSG film is exposed are higher. Therefore, in the present invention, as a cause for improving the (002) orientation of the Ti film, the action of the water absorbed into the BPSG film by leaving the BPSG film in the air or boiling with pure water as described above is considered.

(3) In order to clarify the effect of water on the orientation of the Ti film, the profile of the hydrogen atom (H) concentration in the depth direction near the surface of the BPSG film at different atmospheric exposure times and boiling times is described. ,
It investigated using SIMS analysis (secondary ion mass spectrometry) method. As a result, it was found that the longer the BPSG film left in the air and the longer the boiling time, the higher the H concentration near the surface and the greater the penetration depth of hydrogen atoms.

Further, by integrating this hydrogen concentration profile, the number of hydrogen atoms contained in the vicinity of the BPSG film surface was obtained, and the relationship between this and the (002) orientation of the Ti film was examined. As a result, it became clear that the number of hydrogen atoms and the (002) orientation of the Ti film had an extremely high correlation regardless of whether the film was left in the air or boiled with pure water. That is, as the number of hydrogen atoms near the surface of the BPSG film increases, the T
The (002) orientation of the i film increases. The hydrogen concentration profile is considered to reflect the water concentration profile absorbed by the BPSG film. Therefore, from the above results,
It has been clarified that the increase in the amount of absorbed water on the surface of the BPSG film improves the (002) orientation of the Ti film formed on the surface.

(4) Next, the orientation of the Ti film when the boiling time of the BPSG film in pure water was set to 1 hour or more was examined. There was a tendency that the (002) orientation of the Ti film gradually decreased as the length became longer. BP as described above
The amount of water absorbed by the SG film increases according to the boiling time. Therefore, from the above, when the amount of water on the surface of the BPSG film becomes excessive, the water acts as an impurity on the Ti film, and the presence of this impurity causes the (002)
It is presumed that the orientation decreases. Therefore, B
In order to form a Ti film having excellent (002) orientation on the PSG film, it is necessary to control the water content on the BPSG film surface to an appropriate range.

(5) As a mechanism for promoting the (002) high orientation of the Ti film by the moisture on the BPSG film surface, the moisture in the BPSG film evaporates during the Ti film formation process at a substrate temperature of 350 ° C. Therefore, it is conceivable that water molecules (H ₂ O) or hydrogen atoms (H) and oxygen atoms (O) generated in the Ti film formation atmosphere act during the formation of the Ti film. If this mechanism is appropriate, it is considered that the same effects as the above (1) and (2) can be obtained by introducing an appropriate amount of water, that is, water vapor, into the film formation chamber for the Ti film.

Therefore, in order to clarify this,
The inventor introduced water vapor into a Ti film formation chamber, and formed a Ti film on a BPSG film under the atmosphere. Furthermore, the concentration of the introduced water depends on the H ₂ O in the chamber.
Was measured and controlled by controlling this partial pressure.
As the BPSG film, for example, a film immediately after the heat treatment at 900 ° C. is used so that the influence of the surface moisture absorption of the BPSG film is minimized.

Under the above conditions, H ₂ in the chamber is
The relationship between the O partial pressure and the orientation of the Ti film formed on the BPSG film was examined. As a result, it became clear that the (002) orientation of the Ti film increased with an increase in the H ₂ O partial pressure, and then decreased after showing a maximum value. The maximum value of the (002) orientation of the Ti film was almost the same as the (002) orientation of the Ti film formed on the BPSG film boiled in pure water for one hour. Specifically, the partial pressure of H ₂ O is 1 × 10 ⁻⁸
Within the range of １1 × 10 ⁻⁷ Torr, the Ti (002) orientation showed a high value.

(6) In order to further clarify the mechanism based on the inference of the above (5), oxygen gas (O ₂ ) or hydrogen gas (H ₂ ) was placed in the Ti film deposition chamber instead of water vapor. An experiment similar to the above (2) was attempted by introducing alone. As a result, when each of the oxygen gas and the hydrogen gas is introduced alone, (0
02) It became clear that there was almost no effect in improving the orientation. Accordingly, coexistence of water or oxygen and hydrogen is indispensable for improving the (002) orientation of the Ti film.

(7) In order to obtain the above-described film forming atmosphere, the film forming apparatus is a film forming apparatus for forming a titanium-based material, and H ₂ O is introduced into the film forming chamber. H ₂
O introduction means and partial pressure control means for controlling the H ₂ O partial pressure in the film forming chamber within a predetermined range are provided.

(8) As a film forming apparatus for forming wiring of a semiconductor device, for example, a sputtering apparatus, a single-wafer multi-chamber sputtering apparatus has been conventionally used.

This single-wafer multi-chamber sputtering apparatus includes, for example, a sputtering chamber for forming a Ti film and a TiN film, a sputtering chamber for forming an Al alloy film,
It comprises a load lock chamber for loading and unloading wafers, and a transfer chamber for transferring wafers between each chamber.

However, in the conventional sputtering apparatus, equipment for introducing steam and controlling the partial pressure of H ₂ O is not connected to the sputtering chamber for forming the Ti film and the TiN film. It is difficult to produce a highly oriented Ti film by controlling the partial pressure of H ₂ O.

Therefore, in the present invention, as shown in the above (7), the H ₂ O introducing means and the H
A partial pressure control means for controlling the ₂ O partial pressure.

As a more specific example, a Ti film and a Ti film
A water storage cylinder, a valve for controlling the flow rate of steam, and a pipe for introducing steam into the chamber are provided in a sputtering chamber for forming an N film.
_A partial pressure vacuum gauge for measuring the 2O partial pressure was connected.
Further, in order to accurately control the H ₂ O partial pressure for each wafer, the steam flow control valve is automatically controlled based on the output of the partial pressure gauge in conjunction with the formation of the Ti film and the TiN film. Need a system.

[Summary of the Invention] The present invention relates to a titanium film or a titanium film and a titanium nitride film as described above in order to enhance the (002) orientation of the first layer Ti film formed on the interlayer insulating film. Is characterized in that the semiconductor device is exposed to a gas or liquid atmosphere containing H ₂ O before, during, or before and during the film formation.

A specific method for exposing to gaseous or liquid water is to boil the interlayer insulating film in water for 15 minutes to 3 hours before forming the titanium film. Then, by exposing to the water atmosphere in this manner, a moisture absorbing layer is formed on the surface of the interlayer insulating film before the titanium film is formed.

In another method, when a titanium film or a titanium film and a titanium nitride film are formed, water vapor is introduced into the film formation chamber and the H ₂ O partial pressure in the film formation chamber during the film formation is increased. From 1 × 10 ^-8 to 1 × 10 ^-7 Torr (1
rr ≒ 133 Pa).

The formation of the film in such an atmosphere, upon film formation, film formation and H ₂ O introducing means for introducing of H ₂ O into the chamber within a predetermined range of H ₂ O partial pressure in the deposition chamber And a partial pressure control means for controlling the pressure.

[0038] The film forming apparatus, the H ₂ O introducing means, H ₂
A cylinder for storing O and a valve for controlling the supply of H ₂ O from the cylinder into the film forming chamber are provided. Then, the partial pressure control means, H ₂ in the chamber measured by the pressure gauge to measure the partial pressure of H ₂ O in the film forming chamber
A valve is controlled based on the O partial pressure value to control the amount of H ₂ O supplied from the cylinder into the film forming chamber.

The formed titanium film has 20 to 30% oxygen atoms, 10 to 20% nitrogen atoms, and 0.1 to 0.5%
, And the formed titanium nitride film has a thickness of 8 to 1
Contains 1% oxygen atoms and 2-4% hydrogen atoms. Alternatively, the titanium film contains 0.1 to 0.5% hydrogen atoms, and the titanium nitride film contains 8 to 11% oxygen atoms and 2%.
Configurations containing ４4% hydrogen atoms are also applicable.

With the above configuration, the present invention can form a titanium film having excellent (002) orientation on the interlayer insulating film. Therefore, this (002)
Forming a titanium nitride film etc. on a highly oriented titanium film,
When an Al film (for example, an Al alloy film) is further formed thereon as a wiring layer, the Al alloy film has a high (111) orientation reflecting the (002) orientation of the first titanium film. . Then, the Al with high (111) orientation
The alloy film shows excellent surface smoothness.

Thus, according to the present invention, high (111)
An Al layer having orientation and high surface smoothness can be obtained, and a wiring layer having high electromigration resistance can be formed in a semiconductor device, and highly accurate patterning of wiring can be easily performed.

Further, the present invention is not limited to the titanium nitride film and the aluminum wiring layer as described above, but is a method for manufacturing a semiconductor device having a titanium film formed on a substrate. The semiconductor device is exposed to a gas or liquid atmosphere containing H ₂ O before or during film formation, or before and during film formation. Actually, an insulating film is formed on the substrate, that is, below the titanium film. And even in such a configuration, when a metal layer (wiring layer) is formed on the titanium film, it is possible to realize high electromigration resistance and high smoothness in the metal wiring layer.

Note that a contact hole can be formed in the interlayer insulating film, and a titanium film can be formed also on this contact hole. Furthermore,
As a method for forming a wiring layer such as an Al layer, a vapor deposition method or the like is considered, and PVD (Physical Vapor Deposition), for example, a high-temperature sputtering method or the like can be applied. A configuration in which a titanium film is further provided between the titanium nitride film and the aluminum wiring layer is also applicable.

In the present invention, the substrate is not limited to a semiconductor substrate such as silicon, but may be an insulating substrate such as glass or sapphire, or a compound semiconductor substrate such as GaAs. BPSG is used as the interlayer insulating film.
Various insulating films such as a film, a SiO ₂ film, and a PSG film can be applied.

Furthermore, in the present invention, only the titanium film is shown as the metal film formed on the interlayer insulating film (on the substrate), but it has the same structure as titanium, that is, the hexagonal close-packed structure or the face-centered cubic. A metal material having a lattice structure can be applied instead of the titanium film.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. [Boiling of BPSG film] In the first embodiment,
A BPSG film as an interlayer insulating film, that is, a substrate after the BPSG film is formed is subjected to a boiling treatment in pure water, whereby a BPSG film is formed.
The film surface is absorbing moisture. In the first embodiment, a contact hole is formed on the BPSG film, and a Ti / TiN / Ti underlayer and a high-temperature sputtered Al alloy film are sequentially formed. The (111) orientation and surface irregularities of the film are evaluated.

As shown in FIG. 1, a BPSG film 13 having a thickness of 800 nm was deposited on the surface of the semiconductor substrate 11 as an interlayer insulating film. The B concentration in the BPSG film 13 is 4 wt.
% And the P concentration were 4 wt%. This BPSG film 13 is
Heat treatment was performed at 00 ° C. for 30 minutes in an oxygen atmosphere, and reflow was performed. Next, a normal photolithography process and RI
BPSG film 1 by E (reactive ion etching)
3 and a contact hole 1 having a hole diameter of 0.8 μm
2 was opened.

Further, the BPS including the contact hole 12
The first layer Ti having a thickness of 50 nm is formed as a titanium film on the surface of the G film 13 by sputtering at a substrate temperature of 350 ° C.
A film 14 and a second-layer TiN film 15 having a thickness of 100 nm were continuously deposited in the same chamber. The Ti film 14
Is formed by a normal sputtering method using a Ti target and an Ar gas, and the TiN film 15 is formed by a reactive sputtering method using a mixed gas of a Ti target and Ar + N ₂ . The water pressure in the chamber before forming the Ti film 14 was 4 × 10 ⁻⁹ Torr.

Next, in the first embodiment, a sample was taken out of the chamber and subjected to lamp annealing at 700 ° C. for 180 seconds in a nitrogen atmosphere in order to increase the reliability of the contact portion. In this annealing treatment, the Ti film 14 on the substrate (here, a silicon semiconductor substrate) 11 exposed at the bottom of the contact hole 12 reacts with Si of the substrate 11 to form titanium silicide (TiS
i ₂ ) to stabilize the contact resistance. It is another object of the present invention to improve the film quality of the TiN film 15 formed on the Ti film 14 to improve the barrier property.

After the completion of the annealing, the substrate temperature is set to 350
Further, a 20 nm-thick TiN film 16 and a 50 nm-thick third Ti film 17 were sequentially deposited in the same chamber by sputtering at ° C. Further, the obtained sample is transferred to another chamber in the same apparatus without breaking vacuum, and the Al alloy film 18 and
Specifically, an Al-Si-Cu film having a thickness of 800 nm was deposited. The 20 nm thick TiN film 16 is made of TiN
Oxygen contained in the film 15 diffuses to the surface of the upper Ti film 17 and lowers the wettability to the Al alloy film 18, so that the filling of the contact hole 12 with the Al alloy film 18 becomes incomplete. It is formed for the purpose of preventing the problem.

(Evaluation Results) With respect to the samples obtained by the manufacturing method as described above, the embedding characteristics of the Al alloy in the contact holes were evaluated. As a result, regardless of the boiling time of the BPSG film, Good embedding characteristics were confirmed.

Next, the (111) orientation of the Al alloy film was changed to X
The evaluation was made based on the half value width of the line diffraction rocking curve. Here, the half value width of the rocking curve of the X-ray diffraction means that the smaller the value, the higher the (111) orientation in the entire film.

The degree of surface irregularities of these Al alloy films was evaluated by measuring the surface reflectance of the Al alloy films when irradiated with light having a wavelength of 365 nm. The higher the surface reflectivity, the higher the surface smoothness.

The evaluation results are shown in FIG. In addition,
In FIG. 2, the horizontal axis represents the boiling time (hour) of the BPSG film in pure water at 95 ° C., the left vertical axis represents the half width (degree) of the rocking curve of X-ray diffraction, and the right vertical axis represents the Al alloy film. The surface reflectance (%) is shown.

In FIG. 2, the solid line shows the relationship between the boiling time and the half width. According to the solid line, the half width of the rocking curve is that the boiling time for the BPSG film is 0.25 hours (15 minutes). 0 to 3 hours.
The value is in the range of 65 to 0.8 degrees.

On the other hand, the dotted line in FIG. 2 shows the relationship between the boiling time and the surface reflectance of the Al alloy film. As shown in FIG. Over 90% in the range, and A
It can be understood that the 1 alloy film is obtained.

On the other hand, when boiling is not performed on the BPSG film, that is, when the boiling time is 0 in FIG. 2, the half width is about 2.5 degrees and the surface reflectance is about 6 degrees.
5%.

Further, BP cooked for 15 minutes to 3 hours
With respect to the TiN film 15 / Ti film 14 underlayer formed on the SG film, composition analysis near the surface was performed by Auger electron spectroscopy (AES) and elastic recoil particle detection (ERD). As a result, the TiN film 15 has 8 to 11%
Of oxygen (O) and 2 to 4% of hydrogen (H). The concentration of these oxygen and hydrogen is BP
The longer the boiling time of the SG film, the higher the tendency.

The Ti film 14 has 20 to 30% oxygen (O), 10 to 20% nitrogen (N), and 0.1 to 0.1%.
It was found that it contained 5% hydrogen (H). Note that nitrogen contained in the Ti film 14 is
Nitrogen in the TiN film 15 is diffused by lamp annealing at 700 ° C. for 180 seconds performed after the deposition of the / Ti film 14. The oxygen contained in the Ti film 14 is diffused from the TiN film 15 and the moisture absorbing layer on the surface of the BPSG film by the lamp annealing process.

It should be noted that the conventional T after annealing is performed.
The concentration of oxygen and hydrogen in the iN film and the Ti film is TiN
In the film, oxygen is 5% and hydrogen is 1%. In the Ti film, oxygen is 5% and hydrogen is about 0.1%.

From the above analysis results, in the wiring structure shown in FIG. 1, the Ti film 14 and the TiN film 15 formed on the BPSG film having been boiled for 15 minutes to 3 hours have
The oxygen concentration and the hydrogen concentration are increased about several times as compared with the conventional Ti film and TiN film which are not subjected to this processing. Therefore, the Ti film 14 and the TiN
It was confirmed that the film 15 contained oxygen and hydrogen due to diffusion from the BPSG film.

As described above, by performing boiling treatment in pure water for 15 minutes to 3 hours, the half width is reduced to 1/3 or less and the surface reflectance is improved by 25% or more as compared with the conventional case. I do. Therefore, by the method described in the first embodiment, it is possible to improve the (111) orientation and the surface smoothness of the Al alloy film as the wiring layer.

In the first embodiment, the BPSG
In order to form a moisture absorbing layer on the film surface, the BPSG film is boiled in pure water. However, the method is not limited to this. For example, a method of exposing the BPSG film to a high-temperature, high-humidity gas phase is also applicable. is there.

Embodiment 2 [Introduction of H ₂ O into Ti Film Forming Chamber] In the second embodiment, when manufacturing the semiconductor device having the wiring structure shown in FIG. 1, the BPSG film is not boiled as in the first embodiment. It is characterized in that water vapor is introduced into a film forming chamber when forming a Ti film.

Specifically, in the configuration shown in FIG.
A BPSG film 13 is deposited on the surface of Sample No. 1 and heat-treated at 900 ° C. for 30 minutes in an oxygen atmosphere.
A contact hole 12 is formed on the SG film 13. Next, water vapor was introduced into the chamber of the film forming apparatus to control the H ₂ O partial pressure, and the Ti film 14 and the TiN film 15 were formed continuously. Further, lamp annealing is performed at 700 ° C. for 180 seconds in a nitrogen atmosphere, and thereafter, the TiN film 16 and the Ti film 1
7 were sequentially deposited, and an Al alloy film 18 was formed on the surface of the Ti film 17 by high-temperature sputtering. Then, a plurality of samples having different H ₂ O partial pressures were prepared. In the second embodiment, the film forming conditions other than controlling the partial pressure of H ₂ O by introducing water vapor are the same as those of the first embodiment, including the thickness of each layer.

(Evaluation Results) The samples obtained as described above were evaluated for the embedding characteristics of the Al alloy in the contact holes, the (111) orientation of the Al alloy film, and the surface irregularities, as in the first embodiment. And also Ti / TiN /
The oxygen and hydrogen concentrations in the Ti underlayer were evaluated. The results obtained are as follows.

First, when the embedding characteristics of the Al alloy film in the contact hole were evaluated, good embedding characteristics were confirmed in all samples regardless of the Ti film / TiN film.

The X of the Al (111) plane of the Al alloy film
H ₂ of the half width of the X-ray diffraction rocking curve and the surface reflectance
As for the O partial pressure dependency, the result as shown in FIG. 3 was obtained. In FIG. 3, the horizontal axis represents H at the time of forming the Ti / TiN film.
_{The 2} O partial pressure (Torr), the left vertical axis shows the half width (degree) of the X-ray diffraction rocking curve, and the right vertical axis shows the surface reflectance (%) of the Al alloy film.

As shown by the solid line in FIG.
_{When the} partial pressure of ₂ O is in the range of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁷ Torr, the value is as low as 0.6 to 0.8 degrees. On the other hand, the surface reflectance of the Al alloy film is H
₂ O partial pressure is 1 × 10 ⁻⁸ to 1 × 10 ⁻⁷ Torr as described above.
In the range of 90% or more.

Therefore, according to the second embodiment, it is possible to remarkably improve the (111) orientation and the surface smoothness of the Al alloy film in such a range of the H ₂ O partial pressure.

On the other hand, in the region where the H ₂ O partial pressure is 1 × 10 ⁻⁸ Torr or less where the conventional Ti / TiN film was formed, as is clear from FIG. 3, the (111) orientation of the Al alloy film was Good values have not been obtained for any of the properties and surface smoothness.

Further, the H ₂ O partial pressure at which the (111) orientation and the surface smoothness of the Al alloy film showed high values was 1 × 10 ⁻⁸ to
Embodiment 1 for a sample in the range of 1 × 10 ⁻⁷ Torr
The composition analysis of the TiN film 15 / Ti film 14 was performed in the same manner as described above. As a result, it was confirmed that the TiN films 15 of these samples contained oxygen (O) and hydrogen (H) at substantially the same concentrations as in the first embodiment. The oxygen and hydrogen concentrations tended to increase as the H ₂ O partial pressure increased. In addition, as in the first embodiment, a 20
It was found that it contained ３０30% oxygen (O), 10-20% nitrogen (N) and 0.1-0.5% hydrogen (H).

Therefore, from the results of the composition analysis, [the boiling treatment for 15 minutes to 3 hours] of the embodiment 1 and [H] of the embodiment 2
Ti with ₂ O partial pressure of 1 × 10 ^-8 to 1 × 10 ^-7 Torr
Atmosphere of forming N film 15 / Ti film 14] It has been confirmed that both of these two methods have the same effect on the composition of the TiN film 15 / Ti film 14 underlayer.

The present invention is not limited to the manufacturing methods shown in the above two embodiments.

For example, the wiring structure of the semiconductor device is formed by combining two manufacturing processes of forming a moisture-absorbing layer on the surface of the BPSG film by boiling treatment or the like in Embodiment 1 and introducing steam into the film formation chamber in Embodiment 2. Even if it is formed, the same effect as above can be obtained. However, in this case, it is necessary to set the time of the moisture absorption process on the BPSG film surface and the partial pressure of water vapor at the time of film formation lower than the values exemplified in the first and second embodiments, respectively.

Further, in order to enhance the reliability of the contact portion, after depositing the TiN film 15 / Ti film 14, a lamp annealing process is performed at 700 ° C. for 180 seconds in a nitrogen atmosphere.
Further, a TiN film 16 is additionally formed. However, these processes are not always necessary. It should be noted that the Ti film 14 is used depending on whether or not the lamp annealing process is performed.
Is significantly different, and when no annealing treatment is performed, nitrogen and oxygen are hardly contained in the Ti film 14 (0.
1% or less).

Further, in each of the embodiments, the Al alloy film as the wiring layer is formed by a high-temperature sputtering method at 500 ° C., and the Al alloy is buried in the contact holes simultaneously with the formation of the wiring layer. Not necessarily. For example, after forming an underlayer (TiN film / Ti film, etc.), a contact hole is buried by a tungsten CVD method, and then an Al alloy is formed as a wiring layer at a substrate temperature of 150-3.
A structure formed by a conventional sputtering method at 00 ° C. may be used.

Further, the configuration in which the underlayer is provided on the BPSG film formed on the substrate is shown, but the invention is not limited to this. For example, the present invention can be applied to a configuration in which an interlayer insulating film is formed on a silicon layer formed on a semiconductor substrate or an insulating substrate, and a base layer having excellent compatibility with an Al wiring layer is provided on the interlayer insulating film. is there.

Embodiment 3 In manufacturing the semiconductor device according to the second embodiment, a film forming apparatus as shown in FIG. 4 was used. The device shown in FIG.
film forming chamber 21 for forming i film and TiN film and A
This is a stick-type multi-chamber sputtering apparatus including two sputtering chambers of a 1-alloy (Al-Si-Cu) film, a load lock chamber 23, and a transfer chamber 24. A gate valve 30 is provided between each of the chambers 21, 22, and 23 and the transfer chamber 24.

In this apparatus, each of the chambers 21, 22, 2,
The process gas flow, substrate heating, sputtering film formation, and wafer movement in 3 and 24 are all controlled by the computer 25. Further, in the third embodiment, the computer 25 also functions as a partial pressure control unit that controls the H ₂ O partial pressure in the chamber 21 so as to be within a set range.

In this apparatus, a sputter chamber 21 for forming a Ti film and a TiN film is provided with a cylinder 26 for storing water, and a steam flow rate adjusting device for controlling the steam flow rate from the cylinder 26 into the film formation chamber 21. A valve 27 and a piping 28 for introducing steam into the chamber are provided. Further, the film forming chamber 21 contains H
_A partial pressure vacuum gauge 29 for measuring the 2O partial pressure is connected. In the cylinder 26, H ₂ O is stored in a state where water (liquid) and water vapor coexist, although not necessarily limited thereto.

The valve 27 and the partial pressure gauge 29 are electrically connected to a computer 25 for system control. In this apparatus, immediately after a wafer is loaded into the sputtering chamber 21, the partial pressure
Partial pressure of H ₂ O inside is measured. The computer 25 adjusts the valve 27 based on the measurement result of the partial pressure vacuum gauge 29 and controls the flow rate of steam introduced from the cylinder 26 into the chamber 21. Thus, the H ₂ O partial pressure in the chamber 21 is accurately controlled to a preset value.

Next, an example of a method of manufacturing the semiconductor device shown in FIG. 1 using the above sputtering apparatus will be described.

First, as shown in FIG.
A BPSG film 13 as an interlayer insulating film on the surface of
Deposited to a thickness of The B concentration in the BPSG film 13 is 4 wt%, and the P concentration is 3 wt%. This BPSG film 1
3 is heat-treated at 900 ° C. for 30 minutes in an oxygen atmosphere to perform reflow. Then, by the ordinary photolithography process and RIE (reactive ion etching), B
A contact hole 12 having a hole diameter of 0.8 μm is formed in the PSG film 13.

The load lock chamber 23 of the sputtering apparatus shown in FIG.
3 and the sample in which the contact hole 12 is formed are put. The sample is carried from the chamber 23 through the gate valve 30 and the transfer chamber 24 into the sputtering chamber 21 for forming a Ti film and a TiN film.

After the sample is loaded, the steam flow rate adjusting valve 2
7 is opened to introduce steam into the sputtering chamber 21. The computer 25 is connected to the chamber 2 as described above.
1, the H ₂ O partial pressure is controlled to a desired value, and the surface of the BPSG film including the contact hole 12 has a substrate temperature of 35 ° C.
A sputtering process at 0 ° C. is performed.

By this sputtering, for example, a Ti film 14 having a thickness of 50 nm and a TiN film 1 having a thickness of 100 nm
5 is deposited continuously. Note that the partial pressure of H ₂ O in the chamber 21 before film formation was 4 × 10 ⁻⁹ Torr,
_{The 2} O partial pressure is controlled within the range of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁷ Torr.

The Ti film is formed by using a Ti target and A
The TiN film can be formed by reactive sputtering using a Ti target and a mixed gas of Ar and N ₂ by ordinary sputtering using r gas.

Next, in this embodiment, in order to enhance the reliability of the contact portion, the sample is once taken out of the film forming apparatus shown in FIG. 4 and subjected to a lamp annealing process at 700 ° C. for 180 seconds in a nitrogen atmosphere. Do. By this annealing treatment, T
The i film 14 reacts with the Si of the semiconductor substrate 11 exposed at the bottom of the contact hole 12 to form titanium silicide (T
iSi ₂ ) is formed, and the contact resistance is stabilized. Further, the film quality of the TiN film 15 is improved, and the barrier property is enhanced.

After the annealing treatment, the sample is put into the load lock chamber 23 again, and is transferred via the transfer chamber 24 to the sputtering chamber 2 for forming the Ti film and the TiN film.
Transfer into 1. Then, a 20 nm thick TiN film 16 and a 50 nm thick Ti film 17 are sequentially deposited in the same chamber by sputtering at a substrate temperature of 350 ° C.
Note that, when the TiN film 16 and the Ti film 17 are formed, the supply of water vapor into the chamber 21 is not performed.

Next, the sample is transferred via the transfer chamber 24 into the sputtering chamber 22 for forming an Al alloy film, and the high-temperature sputtering at a substrate temperature of 500.degree. A Si-Cu film is deposited.

By the above procedure, the semiconductor device shown in FIG. 1 is obtained.

Further, with respect to the semiconductor device formed by the above-described procedure, a large number of samples having different H ₂ O partial pressures when forming the Ti film 14 and the TiN film 15 were prepared, and Al was introduced into the contact hole. Embedded characteristics of alloy, A
When the (111) orientation and the surface unevenness of the l alloy film were evaluated, the same evaluation results as in the second embodiment were obtained.

In other words, the embedding characteristics of the Al alloy film in the contact hole were confirmed to be satisfactory in all samples regardless of the partial pressure of H ₂ O in the chamber 21 at the time of Ti / TiN film formation. The X-ray diffraction rocking curve half-width of the Al (111) plane of the Al alloy film and the H ₂ O partial pressure dependency of the surface reflectivity as shown in FIG.
Within the range, the partial pressure of H ₂ O is in the range of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁷ Torr, and the half width is a low value of 0.6 to 0.8 degrees. The surface reflectance is such that the partial pressure of H ₂ O is 1 × 10 ⁻⁸ to 1 × 10
It is a high value of 90% or more in the range of ^-7 Torr.

Therefore, when the Ti film 14 and the TiN film 15 are formed by using the film forming apparatus as shown in this embodiment, H _{2 is used.}
By introducing O into the chamber and setting the H ₂ O partial pressure within a desired range, the (111) orientation and surface smoothness of the Al alloy film can be significantly improved.

[0096]

As described above, according to the present invention, when a wiring layer is formed in a semiconductor device, the (111) orientation of, for example, an Al film as a wiring layer can be improved, and the surface morphology can be improved. It is possible to make it smooth. For this reason, it is possible to form an Al wiring layer capable of high electromigration resistance and highly accurate patterning.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic cross section of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the (111) orientation half width and surface reflectance of an Al alloy film and the boiling time of a BPSG film in Embodiment 1 of the present invention.

FIG. 3 is a diagram showing a relationship between a (111) orientation half width and a surface reflectance of an Al alloy film and a partial pressure of H ₂ O in a chamber at the time of forming a Ti film according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a sputtering apparatus according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a schematic configuration of a conventional semiconductor device.

[Explanation of symbols]

11 substrate, 12 contact holes, 13 BPSG
Film, 14, 17 Ti film, 15, 16 TiN film, 18
Al alloy film, 21 Ti film / TiN film deposition chamber, 22 Al alloy film deposition chamber, 23 load lock chamber, 24 transfer chamber, 25 system control computer, 26 cylinder, 27 water vapor flow control valve, 28 Steam introduction pipe, 29-minute pressure gauge, 30 gate valve.

Continuing from the front page (72) Inventor Hideki Hosokawa 41, Chukumi-Yokomichi, Nagakute-machi, Aichi-gun, Aichi Prefecture Inside of Toyota Central Research Institute, Inc. (72) Inventor Takeshi Owaki Takeshi Owaki, Nagakute-cho, Aichi-gun, Aichi 41 No. 1 Inside Toyota Central Research Laboratories Co., Ltd. (72) Inventor Koichi Mitsushima 41 No. 41, Chuchu-Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture No. 1 Inside Toyota Central Research Laboratories Co., Ltd. 41, Yokomichi, Nagakute-machi

Claims (9)

[Claims] 1. An interlayer insulating film formed on a substrate, a titanium film formed on the interlayer insulating film, a titanium nitride film formed on the titanium film, and formed on the titanium nitride film and a method of manufacturing a semiconductor device having an aluminum wiring layer, said front formation of the titanium film or the titanium film and the titanium nitride film, or during deposition, or deposited before and during the film formation, H ₂ A method for manufacturing a semiconductor device, comprising exposing the semiconductor device to a gas or liquid atmosphere containing O. 2. The method according to claim 1, wherein the interlayer insulating film is formed for 15 minutes to 3 minutes before forming the titanium film.
A method for manufacturing a semiconductor device, comprising performing boiling treatment in water for a time. 3. The method according to claim 1, wherein water vapor is introduced into a film forming chamber when the titanium film, or the titanium film and the titanium nitride film are formed. The H ₂ O partial pressure in the film forming chamber is set to 1 × 10 ⁻⁸
A method for manufacturing a semiconductor device, wherein the method is controlled to 1 × 10 ⁻⁷ Torr. 4. The semiconductor device obtained by the method according to claim 1, wherein the formed titanium film has 20 to 30% oxygen atoms,
The titanium nitride film contains 10 to 20% of nitrogen atoms and 0.1 to 0.5% of hydrogen atoms, and the formed titanium nitride film contains 8 to 11% of oxygen atoms and 2 to 4% of hydrogen atoms. A semiconductor device characterized by the above-mentioned. 5. The semiconductor device obtained by the manufacturing method according to claim 1, wherein the formed titanium film contains 0.1 to 0.5% of hydrogen atoms, A semiconductor device, wherein the formed titanium nitride film contains 8 to 11% of oxygen atoms and 2 to 4% of hydrogen atoms. 6. A method for manufacturing a semiconductor device having a titanium film formed on a substrate, wherein H ₂ O is formed before or during the film formation, or before and during the film formation. A method for manufacturing a semiconductor device, comprising exposing the semiconductor device to a gaseous or liquid phase atmosphere containing the semiconductor device. 7. A film forming apparatus for forming a titanium-based material, in film formation of the titanium-based material, and H ₂ O introducing means for introducing of H ₂ O into the film formation chamber, the deposition chamber A partial pressure control means for controlling a partial pressure of H ₂ O within a predetermined range. 8. The film forming apparatus according to claim 7, wherein the H ₂ O introducing means includes a cylinder for storing H ₂ O, and controls the supply of of H ₂ O into the film forming chamber from the cylinder And a valve, wherein the partial pressure control means controls the valve based on a partial pressure of H ₂ O in the chamber measured by a pressure gauge that measures a partial pressure of H ₂ O in the film forming chamber. Controlling the amount of H ₂ O supplied from the cylinder into the film forming chamber. 9. The film forming apparatus according to claim 7, wherein when forming a titanium film or a titanium film and a titanium nitride film on a substrate, water vapor is supplied into the film forming chamber. Introduce,
During the film formation, the partial pressure of H ₂ O in the film formation chamber was set to 1 ×
A film forming apparatus characterized by controlling the pressure to 10 ^-8 to 1 × 10 ^-7 Torr.