JPH03111567A - Formation of deposited film - Google Patents

Abstract

PURPOSE:To form a Ti-contg. Al film at a desired position with good controllability by introducing gaseous hydrogen contg. alkylaluminum hydride and copper atom into a deposited film forming space contg. a substrate provided with an electron-donative surface at a specified temp. CONSTITUTION:For example, a reaction tube 2 for forming a deposited film forming space is evacuated to a specified vacuum by evacuating equipment 9, and an Si wafer 1 as the substrate is fixed to a holder 3 through a conveyance chamber 10. The surface of the wafer 1 is kept by a heater 4 at a temp. higher than the decomposition temp. of dimethylaluminum hydride(DMAH) and lower than 450 deg.C. Subsequently, DMAH, H2, Si2H6 and Cu(C5H7O2)2 are supplied from gas lines 20-23 with H2 as the carrier gas and introduced into the reaction tube 2 through a mixer 5 to deposit an Al-Si-Cu film on the surface of the wafer 1. A semiconductor device highly integrated and made highly efficient in the semiconductor technical fieled is provided at a low cost by this method.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method of forming a deposited film, and is particularly applicable to wiring of semiconductor integrated circuit devices.
-Sl-C, relates to a method of forming a deposited film.

[Prior Art] Conventionally, aluminum (81) has been mainly used for electrodes and wiring in electronic devices and integrated circuits using semiconductors. Here, ^1 is inexpensive and has high electrical conductivity, and since a dense oxide film is formed on the surface, the inside is chemically protected and stabilized, and the adhesion with Si is good. It has many advantages such as:

By the way, as the degree of integration of integrated circuits such as LSIs has increased, miniaturization of wiring and multi-layer wiring have become especially necessary in recent years, so there are stricter demands than ever on conventional ^1 wiring. are starting to be issued. As dimensions become finer due to increased integration, the surfaces of LSIs, etc., are becoming increasingly uneven due to oxidation, diffusion, thin film deposition, etching, etc. For example, electrodes and wiring metals are not disconnected on stepped surfaces. It must be deposited into a deep pier hole with a small diameter. 4Mbit or 16
In a Mbit DRAM (dynamic RAM), the aspect ratio (pierhole depth/pierhole diameter) of a pierhole in which l must be deposited is 1.0 or more, and the pierhole diameter itself is 1 μm or less. Therefore, there is a need for a technique that can deposit A.degree. C. even in pier holes with large aspect ratios.

In particular, in order to make a reliable connection to a device under an insulating film such as 5i02, it is necessary to deposit 1 so as to fill only the peer holes of the device rather than forming a film. This cannot be achieved by sputtering. This is because the film thickness becomes extremely thin at step portions and on the side walls of the insulating film, and in severe cases, wire breakage occurs.
This is because the reliability of the system will be significantly reduced.

A bias sputtering method has been developed in which a bias is applied to the substrate and the sputter etching action and deposition action on the substrate surface are used to perform deposition so as to fill only the peer holes. However, since a bias voltage of several hundred V or more is applied to the substrate, charged particle damage may occur, for example, in MO.
An adverse effect such as a change in the threshold value of the S-FET occurs. In addition, since etching action and deposition action coexist,
Another problem is that the deposition rate is essentially not improved.

In order to solve the above problems, various types of C
VD (chemical vapor deposit)
ion) method has been proposed. These methods utilize some form of chemical reaction of the source gas during the film formation process. In plasma CvD and photo-CVO, decomposition of the source gas occurs in the gas phase, and the active species generated thereby further react on the substrate to form a film. Since these CVD methods involve reactions in a gas phase, surface coverage against irregularities on the substrate surface is good. However, carbon atoms contained in the source gas molecules are incorporated into the film. In particular, plasma CvD has problems such as damage caused by charged particles (so-called plasma damage) as in the case of sputtering.

In the thermal CVD method, a film grows mainly by a surface reaction on the substrate surface, so that it has good surface coverage over irregularities such as steps on the surface. Further, it can be expected that deposition within the pier hole is likely to occur. Furthermore, disconnections at stepped portions can be avoided.

For this reason, various thermal CVD methods have been studied as a method for forming the ^1 film. - The method of forming an i-film using thermal CV [l] is to disperse organic aluminum in a carrier gas, transport it onto a heated substrate, and then thermally decompose the gas molecules on the substrate to form a film. 0 For example, Journal
of Electrochemical Society
In the example found in Vol. 131, page 2175 (1984), triisobutylaluminum (i-CJe)s Al1 (TIBA) was used as the organic aluminum gas, and the film was formed at a film forming temperature of 260°C and a reaction tube pressure of 0.5 torr. , forming a film of 3.4 μΩ·cm.

JP-A No. 63-33569 describes a method of forming a film by heating organic aluminum (instead of ') in the vicinity of the substrate without using Tick 4. In this method, the natural surface Al2 can be deposited on the metal or semiconductor surface from which the oxide film has been removed.

In this case, it is specified that a step of removing the natural oxide film on the substrate surface is required before introducing TIBA. Also,
Since TIBA can be used alone, there is no need to use a carrier gas other than TIB^, but it is stated that Ar gas may be used as a carrier gas. But T
No reaction between IBA and other gases (for example, H2) is assumed, and there is no mention of using H2 as a carrier gas. In addition to TIB^, trimethylaluminum (
(TMA) and triethylaluminum (TEA), but there is no specific description of other organic metals. This is because, in general, the chemical properties of organic metals change greatly when the m substituent attached to the metal element changes slightly, so it is necessary to individually consider what type of organic metal to use. This method not only has the disadvantage that the native oxide film must be removed, but also has the disadvantage that surface smoothness cannot be obtained. In addition, there is a restriction that the gas must be heated, and that the heating must be done near the substrate, and how close to the substrate the heating must be must be determined experimentally. There are also problems such as not being able to freely choose where to place the heater.

Electrochemical 5ocfety Japan Chapter 2nd Symposium (July 7, 1989) Proceedings page 75 shows A1 by double wall CVD method.
There is a description regarding film formation. In this method, TIBA is used and the apparatus is designed so that the TIBA gas temperature can be made higher than the substrate temperature. This method can be regarded as a modification of the above-mentioned Japanese Patent Application Laid-Open No. 63-33569. Although this method allows selective growth of AlI only on metals and semiconductors, it is not only difficult to precisely control the difference between the gas temperature and the substrate surface temperature, but also requires heating of the cylinder and piping. It has the disadvantage that it cannot be used. Moreover, with this method, a uniform continuous film cannot be obtained unless the film is thickened to a certain extent, and the flatness of the film is poor.

There are other problems.

As mentioned above, the conventional method depends on the flatness of the film.

There are problems with resistance, purity, etc. Further, there was a problem that the film forming method was complicated and difficult to control.

Therefore, the inventors first decided to consider the wiring material itself ^Ji! -C, or A4-5t-(:
By sputtering method using u as a target
A deposited film of Al1-Cu, Al1, -5t-Cu was formed and examined.

However, it was not possible to obtain a film of good quality that exceeded that of No. 81 and met the above-mentioned requirements in terms of flatness, density, and selectivity.

[Problems to be Solved by the Invention] As described above, in the semiconductor technical field where higher integration has been desired in recent years, in order to provide a highly integrated and high-performance semiconductor device at a low price, There was much room for improvement.

The present invention has been made in view of the above-mentioned technical problems, and an object of the present invention is to provide a deposited film forming method capable of forming a high-quality Hel-based metal film as a conductor with good controllability.

Another object of the present invention is to form a deposited film that has excellent flatness and density and is resistant to electromigration and stress migration.

Another object of the present invention is to form a deposited film that is sufficiently applicable to semiconductor integrated circuit devices in which interconnections of, for example, 1.0 μm or less are desired.

[Means for Solving the Problems] Therefore, in the present invention, (a) a step of disposing a substrate having an electron-donating surface in a space for forming a deposited film;
and (c) bringing the temperature of the electron-donating surface to a range above the decomposition temperature of the alkyl aluminum hydride and below 450°C. The method is characterized by comprising a step of maintaining the electron-donating surface and forming an aluminum film on the electron-donating surface.

Further, in the present invention, (a) a step of disposing a substrate having an electron-donating surface in a space for forming a deposited film; (b) a step of using an alkyl aluminum hydride gas and S
(c) introducing a gas containing T, a gas containing Cu, and hydrogen gas into the space for forming the deposited film, and (c) at a temperature equal to or higher than the decomposition temperature of the alkyl aluminum hydride;
It is characterized by comprising a step of maintaining the temperature of the electron-donating surface within a range of 50° C. or less and forming an aluminum film on the electron-donating surface.

[Function] In a reaction system of a gas containing Al2, a gas containing Cu, and a hydrogen gas, or a gas containing St, 1-Cu or A°C-5i-Cu is applied to the surface of the substrate as a simple reaction. Deposits only by thermal reaction.

That is, for example, a mixture of the above gases is supplied onto a substrate heated to an appropriate temperature range, and by appropriately determining the pressure in the space, Al2-Cu or Al2-5i-C is deposited on the surface. deposits and forms a continuous film which grows. Therefore, low resistance, dense and flat A11-
A Cu or Al2-5i-(:u film can be deposited on the substrate.

[Example] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

In the present invention, high quality Al2-
A CVD method is used to selectively deposit a Cu film or an Al1-5i-C film on a substrate.

In other words, at least one atom that becomes a component of the deposited film is
dimethylaluminum hydride (DMAH) or monomethylaluminum hydride (MMAH2), which are organometallic, as a raw material gas, and a gas containing Si atoms as a raw material gas,
In addition, H2 is used as a reaction gas, and an AJ-based gold metal film is formed on the substrate by vapor phase growth using a mixed gas of these.

The substrate to which the present invention can be applied uses a material having electron donating properties.

This electron donating property will be explained in detail below.

An electron-donating material is one in which free electrons exist in the substrate or free electrons are intentionally generated.For example, a chemical reaction occurs through electron transfer with raw material gas molecules attached to the surface of the substrate. A material with a surface that is promoted. For example, metals and semiconductors generally correspond to this.

It also includes those in which a thin oxide film exists on the surface of a metal or semiconductor. This is because a chemical reaction occurs between the substrate and the attached raw material molecules due to electron exchange.

Specifically, semiconductors such as single crystal silicon, polycrystalline silicon, and amorphous silicon, Ga and In as group III elements
, 81 and P, As, and N as group V elements, binary, ternary, or quaternary group III-V compound semiconductors, tungsten, molybdenum, tantalum,
Tungsten silicide, titanium silicide, aluminum, aluminum silicon, titanium aluminum, titanium nitride.

Includes metal 1 alloys such as copper, aluminum silicon copper, aluminum palladium, titanium, molybdenum silicide, tantalum silicide, and their silicides.

On a substrate having such a structure, ^n-5i-Cu or AfL-C is deposited by a simple thermal reaction in the reaction system of the raw material gas and 82. For example, DMAI+ and 1
The thermal reaction in the reaction system with 12 is basically thought to be H3'``''l(' heshi 3. DMAH has a dimeric structure at room temperature.

Also, 5i2Hs etc. and alkyl steel compounds such as c
By adding u(csHy(h) 2 etc., AJ2-5i-
The reason why Cu or ^1-cu is formed is that 5i2H2 and Cu(c88702)2 that have reached the surface of the substrate are decomposed by a surface chemical reaction, and Si and Cu are incorporated into the film. Even with MMAHz, high quality AJ2-C and AJ2-5i-Cu could be deposited by thermal reaction, as shown in the examples below.

MMAH2 has a vapor pressure of 0.01 to 0.0 at room temperature. ITorr
The upper limit of the deposition rate in the present invention is several hundred people/minute, and it is most desirable to use DMAH, which has a vapor pressure of ITorr at room temperature.

FIG. 1 is a schematic diagram showing a deposited film forming apparatus to which the present invention can be applied.

Here, 1 is a substrate for forming a λ-based metal film. A substrate 1 constitutes a reaction tube 2 that is placed on a substrate holder 3 provided inside a reaction tube 2 for forming a substantially closed space for forming a deposited film. Although quartz is preferable as the material, metal may also be used.
In this case, it is desirable to cool the reaction tube. Also,
The substrate holder 3 is made of metal, and is provided with a heater 4 to heat the substrate placed thereon. and heater 4
The substrate temperature can be controlled by controlling the heat generation temperature of the substrate.

The gas supply system is configured as follows.

Reference numeral 5 denotes a gas mixer, which mixes the first raw material gas, the second raw material gas, and the reaction gas, and supplies the mixture into the reaction tube 2 .

Reference numeral 6 denotes a source gas vaporizer provided to vaporize an organic metal as a first source gas.

Since the organic metal used in the present invention is in a liquid state at room temperature, a carrier gas is passed through the organic metal liquid in the vaporizer 6 to form a saturated vapor, and then introduced into the mixer 5.

20 is a line for raw material gas and carrier gas, 21 is a line for H2 which is a reaction gas, and 22 is a line for gas containing St atoms for mixing additives. ).

Reference numeral 23 denotes a gas supply line containing Cu atoms for mixing another additive.

Furthermore, the additive gas line 23 of this device. The mixer 5 and the reaction tube 2 have a structure that can be heated up to 250°C.

The exhaust system is configured as follows.

Reference numeral 7 denotes a gate valve, which is opened when a large volume of gas is evacuated, such as when evacuating the inside of the reaction tube 2 before forming a deposited film. 8
is a slow leak valve, which is used for reaction tube 2 during deposition film formation.
Used when evacuation of a small volume, such as when adjusting internal pressure. Reference numeral 9 denotes an exhaust unit, which is composed of an exhaust pump such as a turbo molecular pump.

The transport system for the substrate 1 is configured as follows.

Reference numeral 10 denotes a substrate transfer chamber capable of accommodating substrates before and after the formation of a deposited film, and is evacuated by opening a valve 11. Reference numeral 12 denotes an exhaust unit for evacuating the transfer chamber, and is composed of an exhaust pump such as a turbo molecular pump.

The valve 13 is opened only when the substrate 1 is transferred between the reaction chamber and the transfer space.

As shown in FIG. 1, in the vaporizer 6 for producing raw material gas, a liquid DMA1 kept at room temperature is used.
Gaseous DM is produced by bubbling H with H3 or Ar (or other inert gas) as a carrier gas.
AH is produced and sent to the mixer 5 via the gas line 20.
Transport to. H2 as reaction gas is transported from line 21 to mixer 5. The additive gas containing Cu atoms is transported via line 23 to mixer 5 . Further, an additive gas containing Si atoms is transported to the mixer 5 via a line 22 as required. The flow rate of each gas is adjusted so that its partial pressure becomes a desired value.

Although MMA) may be used as the first raw material gas, MAH is most preferable because it has a vapor pressure of ITorr at room temperature. Alternatively, DMAH and MMAH2 may be used in combination.

Further, as the gas containing Cu as the second raw material gas (additional gas), bisacetylacetonatocopper Cu (c8B?
0□)2. Bisdipivaloylmethanatocopper Cu (c+xL
eOa)z, bishexafluoroacetylacetonatocopper cu(csHF, O□)2 can be used.

Among them, C has the lowest carbon content and does not contain F.
, (c,H,02) 2 are most preferred.

However, since the above materials are solid at room temperature and need to be transported by sublimation, the second raw material gas (additional gas) line 23
．． Mixer 52 and reaction tube 2 need to be preheated to about 180°C.

Further, it is more effective to flow Ar or H7 carrier gas through the second source gas line 23.

Further, as the gas containing St as the third raw material gas, Si2H6, SiH4, 5iJa, Si (cH3)
4. t4゜5IHzCj to Si'C! 2.5iHs
Cn can be used. In particular, 200-300
5t2H, which is easily decomposed at a low temperature of °C, is most desirable. ■2
Or gases such as Si, H, etc. diluted with Ar can be used as DMA
If necessary, it is transported to the mixer 5 from a line 22 separate from H and supplied to the reaction tube 2.

Using such raw material gas and reaction gas, the substrate temperature is 2
As a result of analysis of the film formed at 20° C. to 450° C. by Ausch electron spectroscopy or photoelectron spectroscopy, no impurities such as carbon or oxygen were found to be mixed into the film.

Furthermore, the resistivity of the deposited film is 2.0 at room temperature for a film thickness of 400.
It has a resistivity of 7 to 3.0 μΩ·cm, which is approximately equal to the resistivity of the ^1 bulk, resulting in a continuous and flat film. Furthermore, even if the film thickness is 1 μm, its resistivity is approximately 2.7 to 3.0 μm at room temperature.
Ω·cm, and a sufficiently dense film can be formed even if it is thick. The reflectance in the visible light wavelength region is also approximately 80%,
Thin films with excellent surface flatness can be deposited.

As mentioned above, the substrate temperature is desirably above the decomposition temperature of the source gas including A° C. and below 450° C., but specifically, a substrate temperature of 220 to 450° C. is desirable, and the deposition is performed under these conditions. If DMA8 partial pressure is 10-
'~10-'Torr, deposition rate is 400λ/min~
Very large, 1000 people/min, AI for VLSI: t-
5i-C, a sufficiently high deposition rate can be obtained as a deposition technique.

More preferably, the substrate temperature is 250°C to 350°C,
A11. deposited under these conditions. -5i-C, the film has strong orientation, and is of good quality with no hillocks or spikes on Si single crystal, St polycrystalline substrates, or oxide films even after heat treatment at 450°C for 1 hour.
-It becomes a Cu film. Moreover, such Al2-5i-C,
The film has excellent electromigration resistance, and the amounts of St and Cu can be easily controlled.

In the apparatus shown in the first figure, Afl-5N-Cu can only be deposited on one substrate in one deposition. Although a deposition rate of approximately 800 persons/min can be obtained, this is insufficient for depositing a large number of sheets in a short period of time.

As a deposited film forming apparatus that improves this point, there is a low pressure CVD apparatus that can load a large number of wafers at the same time and deposit A,9-5i-Cu according to the present invention.
-5t-Cu deposition uses a surface reaction on the heated electron-donating substrate surface, so if the hot wall type low pressure CVD method in which only the substrate is heated, DMAH and H2
Cu ((:5lhOz) Cu raw material gas such as 2 and 5
By adding St raw material gas such as t2H, C
A containing u from 0.5 to 2.0 and Si from 0.5 to 2.0 zero
A l2-5i-Cu film can be deposited.

The reaction tube pressure is 0.05 to 760 Torr, preferably 0
．． 1~Q, 8 Torr, substrate temperature 220℃~450
℃, preferably 250℃ to 400℃, DMA8 partial pressure is IX 10-' times to 1.3 xlO-' times the pressure inside the reaction tube, Cu (c5H702) 2 partial pressure is 5 times the pressure inside the reaction tube.
X 10-' times ~ 5 X 10-' times, Si, l (, partial pressure is I X 10-' times ~ I X 10
-' times the range, and Al1-5t-Cu is deposited on the electron-donating substrate.

FIG. 2 is a schematic diagram showing a deposited film forming apparatus to which the present invention can be applied.

57 is a substrate for forming an Al1-5i-C or 1-Cu film. Reference numeral 50 denotes an outer reaction tube made of quartz that forms a substantially closed space for forming a deposited film, and 51 refers to a quartz tube installed to separate the gas flow within the outer reaction tube 50. 54 is a metal flange for opening and closing the opening of the outer reaction tube 50, and the base 57 is installed in a base holder 56 provided inside the inner reaction tube 51. Note that the base holder 56 is preferably made of quartz.

Furthermore, the present device can control the substrate temperature using the heater section 59. The pressure inside the reaction tube 50 is controlled by the gas exhaust port 5.
The exhaust system is configured to be controlled by an exhaust system connected via 3.

In addition, the raw material gas has a first gas system, a second gas system, a third gas system, a fourth gas system, and a mixer (all of which are not shown), similar to the apparatus shown in FIG. The raw material gas is introduced into the reaction tube 50 from the raw material gas introduction line 52.

The third raw material gas line and the raw material gas introduction line 52 have a heating mechanism similar to the device shown in FIG. The raw material gas and the reaction gas are as shown by arrow 58 in FIG.
When passing through the inner reaction tube 51, it reacts on the surface of the substrate 57 and deposits AJZ-5t-Cu on the surface of the substrate. The gas after the reaction passes through the gap formed by the inner reaction tube 51 and the outer reaction tube 50 and is exhausted from the gas exhaust port 53.

When taking out and putting in the base, the metal flange 54 is lowered together with the base holder 56 and the base 57 by an elevator (not shown), and moved to a predetermined position to attach and detach the base.

By using such an apparatus and forming a deposited film under the conditions described above, all wafers in the apparatus can be of good quality.
A -5t-Cu film can be formed at the same time.

(Left below) As mentioned above, the film obtained by the <1-5l-Cu film forming method according to the present invention is dense, contains very little impurities such as carbon, has a resistivity comparable to that of bulk material, and has a high surface resistance. Since it has a characteristic of high smoothness, the remarkable effects described below can be obtained.

(2) Reduction of hillocks Hillocks are caused by partial migration of A1 when the internal stress during film formation is released in the heat treatment step, resulting in a convex portion on the surface of A1. A similar phenomenon also occurs due to local migration due to energization. The Q-5i-Cu film formed according to the present invention has almost no internal stress and is in a state close to single crystal. Therefore, while 10' to 10' hillocks/cm2 are generated in the conventional +1-5i film by heat treatment at 450°C IHr, according to the present invention, the number of hillocks is 0 to 100/Cl1.
12, which was a huge achievement. Like this ^lt-5i-C
Since there are almost no convex portions on the u surface, the resist film thickness and the interlayer insulating film can be made thinner, which is advantageous for miniaturization and planarization.

■Improving electromigration resistance Electromigration is a phenomenon in which wiring atoms move due to the flow of high-density current. This phenomenon generates and grows voids along the grain boundaries, which reduces the cross-sectional area and causes heat generation and disconnection of the wiring.

Migration resistance is generally evaluated based on the average wiring life.

The wiring according to the above conventional method is heated at 200°C.
Under the current test conditions of /Cl112, the wiring cross-sectional area is 2 μm2
In this case, an average wiring life of 1X10' to 103 hours has been obtained. Based on this invention, AA-51-
The AA-5i-Cu film obtained by the Cu film formation method was found to have a maximum width of 4 x 10 in a wiring with a cross-sectional area of 2 μm2 in the above test.
An average wire life of 3 hours was obtained.

■Improvement of resistance in contact holes and through holes and contact resistance.

When the size of the contact hole becomes smaller than 1 μm x 1 μm, Si in the wiring precipitates and covers the base of the contact hole during heat treatment during the wiring process, significantly increasing the resistance between the wiring and the element. Become.

According to the present invention, a dense film is formed by surface reaction, so Al1-5t-Cu completely filled inside contact holes and through holes can have a resistivity of 2.7 to 3.3 μΩcm. confirmed. In addition, the contact resistance is 1 in the St part in a hole of 0.8μ0IX0.8μm.
1×1O-6Ω・C if it has impurities of 0"cm-'
11' can be achieved.

In other words, according to the present invention, it is possible to completely embed the wiring material into the minute hole, and to obtain good contact with the substrate. Therefore, the present invention can greatly contribute to improving the after-hole resistance and contact resistance, which are the biggest problems in microprocesses of 1 μl or less.

(Example 1) First, the procedure for film formation at 3°C-5t-C is as follows.

Using the apparatus shown in FIG. 1, the inside of the reaction tube 2 is evacuated to approximately I.times.10-'Torr using the exhaust equipment 9. However, AIL-5i-Cu can be formed even if the degree of vacuum in the reaction tube 2 is worse than I x 10-'Torr.

After cleaning the Si wafer, the transfer chamber 1o is released to atmospheric pressure and the Si wafer is cleaned.
Load the wafer into the transfer chamber. The transfer chamber is approximately 1×1O-6
After exhausting to Torr, the gate valve 13 is opened and the wafer is mounted on the wafer holder 3.

After placing the wafer on the wafer holder 3, the gate valve 1
3 is closed, and the degree of vacuum in the reaction chamber 2 is approximately lX10-'Tor.
Exhaust until r.

In this embodiment, DMAH is supplied from the first gas line. H2 was used as the carrier gas for the DMA)1 line.

The second gas line is for H2, and the third gas line is for Cu(
csToOz) 2, the fourth gas line is 5i2H,
For use. Further, the third gas line, mixer, and reaction tube are preheated and set at 180°C±10°C.

Crush H2 from the second gas line and slow soak valve 8
Adjust the opening degree of the pressure inside the reaction tube 2 to a predetermined value.
Typical pressure in this example is approximately 1.5 Torr. Thereafter, the heater 4 is energized to heat the cube. After the wafer temperature reaches the predetermined temperature, the DMA) l line,
(:u(csHlot) z line, DMAH, C, (c5H,02)2, 5i2H from 512Hs line
, is introduced into the reaction tube. Total pressure is approximately 1.5 Torr
, the DMA8 partial pressure is approximately 1.5 x 10-'To
Let it be rr. Cu (c8H702) 2 partial pressure is I
10””Torr, 5i2H6 partial pressure is 1 x 10
−'Torr. When Si, H, and DMAH are introduced into the reaction tube 2, ^1l-5t-Cu is deposited. After the predetermined deposition time has elapsed, DMAH,Cu (c5H70
2) Stop the supply of 2 and 5i2H. Next, heating of the heater 4 is stopped and the wafer is cooled. After stopping the supply of H2 gas and evacuating the inside of the reaction tube, the wafer is transferred to the transfer chamber, and after only the transfer chamber is brought to atmospheric pressure, the wafer is taken out. The above is an outline of the procedure for forming the ^1-5i-Cu film.

Next, sample preparation in this example will be explained.

Hydrogen combustion method (H2:
3A /M, 02: 2f1. /M) to 1000℃
Thermal oxidation was carried out at a temperature of

Prepare the above-mentioned wafer with an oxide film, and according to the procedure described above, total pressure: 1.5 Torr DMAH partial pressure: 1.5 x 10-' Torr
rCu (c8H?02) 2 partial pressure I X 10-'T
orrSi, H6 partial pressure I X 1G-'Tor
AJl-5t-Cu film was deposited 500 times under the conditions of r, and using ordinary photolithography technology, AJl-
Buttering was performed so that 5t-C was left in a width of 2.4.6μ.

Table 1 shows evaluations of films deposited by varying the deposition substrate temperature (Ts) and by varying the wiring width of +1-5i-C.

In the above sample, a film with extremely few hillocks and excellent electromigration resistance could be obtained in the temperature range of 220°C to 400°C.

Moreover, the buttering properties of this^12-5s-Cu were also extremely good.

(Example 2) A fl-3i-C film was deposited on the same substrate as in Example 1 using the apparatus shown in FIG. 2 with the following settings.

Total pressure 1.5Torr DMAH partial pressure 5 X 10-'TorrS
i,)1. Partial pressure I X 10-'TorrCu
(csLOz) 2 Partial pressure 1 x 10-'Torr Substrate temperature 300°C As a result, a flat and dense Al2-St-Cu film with excellent migration resistance as in Example 1 was obtained.

(Example 3) Total pressure: 1.5 Torr DMAH partial pressure: 5 X 10-'TorrS using the same procedure as Example 1
Set i2H@partial pressure 1 x 10-'Torr substrate temperature (Tsub) 300℃, set Cu (csHy(h) 2 partial pressure 5 x
Deposition was performed by varying the Cu content (wt%) from 0.3% to 4% in the formed Al1-5i-Cu film.
(c5H?02) 2 Changed by partial pressure. Results similar to those of Example 1 were obtained regarding resistivity, carbon content, average wiring life, deposition rate, and hillock density. However, samples with a Cu content of 3% or more had poor surface morphology.

(Example 4) Using the same procedure as in Example 1, the total pressure was 1.5 Torr DMA+ (partial pressure 5
C, (c9H702) partial pressure 1 x 1O-8Tor
Set the r substrate temperature (Tsub) to 300℃, and set the 5iJ6 partial pressure to 1.5 x 10-'Tor.
The AI was completed in 6 seconds with deposition varying from r to 1×10-'Torr! , the Si content (wt%) in the -5t-Cu film ranges from 0.005% to 5%5t2)1
．． It changed depending on the partial pressure. The same results as in Example 1 were obtained regarding resistivity, average wiring life, deposition rate, and hillock density. However, in a sample having a Si content of 4% or more, precipitates that appeared to be Si were formed in the film, resulting in poor surface morphology and a reflectance of 65% or less. Si content 4%
The reflectance of the samples below was 80-95%, which was similar to Example 1.

(Example 5) Using the same procedure as in Example 1, the total pressure was adjusted to 1.5 Torr DM8I (to partial pressure 5 X 10-' Torr
Cu (c5H702) partial pressure I X 10-'Tor
The substrate temperature was set at 300° C., and the deposition was performed without flowing any Si or H. Formed Al2-C, C content in the film is 0.5%
In the evaluation regarding electromigration resistance, results better than those of Example 1 were obtained.

(Example 6) The total pressure was adjusted to 1.5 TorrDMAH partial pressure using the same procedure as in Example 1.
5 X fO-'TorrSi2H61X
10-'Torr Cu(c+ +HI902) 2 Partial pressure I X 10-
'Torr was set and 42-5i-C was deposited.

In the substrate temperature range of 220° C. to 400° C., similarly to Example 1, an AIL-St-Cu film with excellent migration resistance, flatness, and excellent density was obtained.

(Example 7) Total pressure: 1.5 Torr DMAH partial pressure: 5 x 10-'TorrSi
2H6 partial pressure I X 10-'TorrCu(c
5HF802) 2 The hx-st-cu was deposited by setting the partial pressure I x 10-'Torr.

Similar to Example 1, a flat An-5t-Cu film with excellent migration resistance and excellent density was obtained in the substrate temperature range of 220° C. to 400° C.

(Example 8) Similarly to Example 2, a low-pressure CVD device shown in FIG. 2 was used to selectively coat the single crystal silicon surface on which a 5t-Cu film was formed on the substrate A1-5 having the configuration described below. 10" cm of phosphorus is diffused into the surface, thermally oxidized 5iOJJ is formed thereon, and buttering is performed using a shell-like photolithography process.
The single crystal silicon surface was partially exposed.

At this time, the thickness of the thermally oxidized 5i02 film was 7,000 mm, and the exposed area of single crystal silicon, that is, the size of the opening, was 0.68 μm×0.
It was 8 μm. The sample was prepared in this way,
.

These samples were placed in the low pressure CVD apparatus shown in FIG. 2, and an Al1-5i-cm film was formed within the same badge.

The film forming conditions were a tube pressure of 0.3 Torr and a DMAH partial pressure of 3.
, OX 10-'Torr, 5i2Hl1 partial pressure 1. O
x 10-'Torr.

C, (c51t702)2 partial pressure 1 x 1ff-7To
rr, substrate temperature 300° C., and film formation time 10 minutes.

As a result of film formation under these conditions, the contact resistance between the phosphorous-diffused silicon region and the deposited Ax-si-cm film was 8X10-' to 1.2X10-'Ω·C112. In other words, without installing barrier metal etc. inside the pier hole, the inside of the pier hole is deposited A, il -5i-
It was possible to obtain good contact resistance and in-hole resistance by filling with CI7.

[Effects of the Invention] As explained above, according to the present invention, low resistance, dense,
and flat Afl-5i-Cu and i-C.

A film could be deposited onto the substrate.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a deposited film forming apparatus to which the present invention can be applied, and FIG. 2 is a schematic diagram showing another example of a deposited film forming apparatus to which the present invention can be applied. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Reaction tube, 3... Substrate holder, 4... Heater, 5... Mixer, 6... Vaporizer, 7... Gate valve, 8... - Slow leak valve, 9... Exhaust unit, 10... Transfer chamber, 11... Valve, 12... Exhaust unit, 20... Raw material gas line, 21... Reaction gas line, 22... ...Second source gas line, 23...Third source gas line, 50...Quartz outer reaction tube, 51...Quartz inner reaction tube, 52...Source gas introduction line, 53 ...Gas exhaust port, 54...Metal flange, 56...Base holder, 57...Base, 58...Gas flow, 59...Heater part.

Claims (1)

[Claims] 1) (a) A step of disposing a substrate having an electron-donating surface in a space for forming a deposited film; (b) a step of disposing an alkyl aluminum hydride gas, a gas containing copper atoms, and a hydrogen gas; (c) maintaining the temperature of the electron-donating surface within a range of not less than the decomposition temperature of the alkyl aluminum hydride and not more than 450°C; A method for forming a deposited film, comprising the step of forming it on a donating surface. 2) (a) A step of disposing a substrate having an electron-donating surface in a space for forming a deposited film; (b) A step of adding an alkyl aluminum hydride gas, a silicon-containing gas, a copper atom-containing gas, and a hydrogen gas to the (c) maintaining the temperature of the electron-donating surface within a range of not less than the decomposition temperature of the alkyl aluminum hydride and not more than 450°C; 1. A method for forming a deposited film, the method comprising the step of forming a deposited film on a surface of a metal. 3) The deposited film forming method according to claim 1 or 2, wherein the alkyl aluminum hydride is dimethyl aluminum hydride. 4) The deposited film forming method according to claim 1 or 2, wherein the alkyl aluminum hydride is monomethyl aluminum hydride.