JP2801285B2 - Deposition film formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [FIELD OF THE INVENTION The present invention relates to a deposited film forming method, Al-C _u or can particularly preferably applied to a wiring of a semiconductor integrated circuit device Al-
It relates a method of forming a Si-C _u deposited film.

[Prior Art] Conventionally, in electronic devices and integrated circuits using semiconductors, aluminum (Al) has been mainly used for electrodes and wirings. Here, Al is inexpensive, has high electric conductivity, and a dense oxide film is formed on the surface, so that 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 and miniaturization of wiring and multi-layer wiring have become particularly necessary in recent years, there has been an ever more stringent demand for conventional Al wiring. It is being issued. Along with miniaturization due to an increase in the degree of integration, the surface of an LSI or the like has become increasingly uneven due to oxidation, diffusion, thin film deposition, etching, and the like. For example, an electrode or a wiring metal must be deposited on a stepped surface without disconnection or deposited in a via hole having a small diameter and a large diameter. 4Mbit and 16Mbit DAR
In an M (dynamic RAM) or the like, the aspect ratio (via hole depth / via hole diameter) of the via hole in which Al must be deposited is 1.0 or more, and the biohole diameter itself is 1 μm or less. Therefore, a technique that can deposit Al even in a via hole having a large aspect ratio is required.

In particular, in order to reliably connect a device under an insulating film such as SiO ₂ , it is necessary to deposit Al so as to fill only a via hole of the device rather than forming a film. This cannot be realized by the sputtering method. This is because the film thickness at the step portion and the side wall of the insulating film becomes extremely thin, and in severe cases, disconnection occurs, and unevenness of the film thickness or disconnection significantly lowers the reliability of the LSI.

Apply a bias to the substrate and use only the sputter etching and deposition effects on the substrate surface to
A bias sputtering method for performing deposition so as to bury Al has been developed. However, since a bias voltage of several hundred volts or more is applied to the substrate, damage to charged particles, for example, MOS-FET
Has an adverse effect such as a change in the threshold value. In addition, there is a problem that the deposition rate is not essentially improved because the etching action and the deposition action are mixed.

To solve the above problems, various types of
A CVD (Chemical Vapor Deposition) method has been proposed. In these methods, a chemical reaction of a source gas is used in some way during the film formation process. In plasma CVD and optical CVD, the decomposition of the source gas occurs in the gas phase, and the activated species formed there further react on the substrate to form a film. In these CVD methods, there is a reaction in the gas phase, so that the surface covering property against unevenness on the substrate surface is good. However, carbon atoms contained in the source gas molecules are taken into the film. In particular, plasma CVD has a problem such as damage by charged particles (so-called plasma damage) as in the case of the sputtering method.

In the thermal CVD method, the film grows mainly by the surface reaction on the surface of the substrate, and therefore, has good surface coverage with irregularities such as steps on the surface. Also, it can be expected that deposition in the via hole is likely to occur. In addition, disconnection at the step can be avoided.

Therefore, various studies have been made on thermal CVD as a method for forming an Al film. As a general method of forming an Al film by thermal CVD, a method is used in which organic aluminum is dispersed in a carrier gas, transported onto a heated substrate, and gas molecules are thermally decomposed on the substrate to form a film. For example, Journal of Electrochem
ical Society No. 131 Volume 2175 pages with triisobutylaluminum as an organic aluminum gas in the example seen in _{(1984) (i-C 4 H 9} ) 3 Al (TIBA), film formation temperature of 260
The film was formed at a temperature of 0.5 ° C. and a reaction tube pressure of 0.5 torr to form a film of 3.4 μΩ · cm.

JP The 63-33569 discloses without using TiCl _4, a method of film formation is described by heating the organoaluminum instead in the vicinity of the substrate. In this method, the metal or semiconductor surface from which the natural oxide film has been removed
Can be deposited.

In this case, it is specified that a step of removing a natural oxide film on the substrate surface is necessary before introducing TIBA. Also, TI
Since BA can be used alone, it is not necessary to use a carrier gas other than TIBA, but it is described that Ar gas may be used as a carrier gas. However, no reaction between TIBA and another gas (for example, H ₂ ) is assumed at all, and there is no mention of using H ₂ as a carrier gas. In addition, other than TIBA, trimethylaluminum (TMA) and triethylaluminum (TEA) are mentioned, but there is no specific description of the other organic metals. This is because the chemical properties of organometallics generally change greatly when the organic substituent attached to the metal element changes slightly, and it is necessary to individually consider what kind of organometallic should be used. This method not only has the disadvantage that the natural oxide film must be removed, but also has the disadvantage that surface smoothness cannot be obtained. In addition, it is necessary to heat the gas, and there is a restriction that heating must be performed near the substrate, and it is necessary to experimentally determine how close the substrate must be heated. There is another problem that the place where the heater is placed cannot be freely selected.

Proceedings of the 2nd Symposium of the Electrochemical Society Japan Chapter (July 7, 1989), page 75, contain a description of Al film formation by double-wall CVD. In this method, TIBA is used and an apparatus is designed so that the gas temperature of TIBA can be higher than the substrate temperature. This method can be regarded as a modification of the above-mentioned JP-A-63-33569. With this method, Al can be selectively grown only on metals and semiconductors.However, it is not only difficult to accurately control the difference between the gas temperature and the substrate surface temperature, but also if the cylinder and piping are not heated. There is a disadvantage that it does not. Moreover, in this method, a uniform continuous film cannot be obtained unless the film is thickened to some extent.
There are problems such as poor film flatness.

As described above, the conventional method has problems in the flatness, resistance, purity, and the like of the Al film. In addition, there is a problem that the film forming method is complicated and difficult to control.

Accordingly, the present inventors have first by sputtering method using an Al-C _u or Al-Si-C _u in order to examine the wiring material itself as the target Al-C _u or Al-
Si-C was deposited film is formed study of _u.

However, a high quality film that surpasses Al in terms of flatness, denseness, and selectivity and satisfies the above-mentioned requirements was not obtained.

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

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

Another object of the present invention is to form a deposited film which is excellent in flatness and denseness and resistant to electromigration and stress migration.

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

[Means for Solving the Problems] Therefore, a method for forming a deposited film according to the present invention comprises the steps of: Disposing a substrate having a surface made of a selected material or a silicide thereof in a space for forming a deposited film, and supplying dimethyl aluminum hydride and / or monomethyl aluminum hydride gas and hydrogen gas to the space for forming a deposited film; Introducing, a step of preheating a gas containing copper atoms and introducing the gas into the space for forming the deposited film, and a temperature of 250 ° C. or more and 350 ° C.
Maintain the temperature of the surface within the following range, 0.5 to 2.0 copper
%, And a step of forming an aluminum film having a hillock number of 100 / cm ² or less on the surface.

Further, the method for forming a deposited film according to the present invention includes the steps of:
Molybdenum, tantalum, aluminum, aluminum silicon, titanium aluminum, titanium nitride,
Disposing a substrate having a surface selected from a material selected from copper, aluminum silicon copper, aluminum palladium, and titanium or a silicide thereof in a space for forming a deposited film, a gas of dimethyl aluminum hydride and / or monomethyl aluminum hydride; Introducing a gas containing silicon consisting of one of silicon hydride, alkylated silicon, silicon halide, halogen hydride or silicon and a hydrogen gas into the space for forming the deposited film, including copper atoms A step of preheating a gas and introducing the gas into a space for forming the deposited film, and
Maintaining the temperature of the surface within the range of not less than 250 ° C. and not more than 350 ° C., including 0.5 to 2.0% silicon and 0.5 to 2.0% copper;
A step of forming an aluminum film having a hillock number of 100 / cm ² or less on the surface.

Relative [work for] the substrate surface, and a gas containing Al, the Al-C _u or Al-Si-C _u in the reaction system with a gas containing C _u gas containing hydrogen gas or even Si, It is deposited only by a simple thermal reaction.

Thus, for example more than mixed gas of the gas is supplied onto the heated to a suitable temperature range base, by determining appropriately the pressure in the space, the surface Al-C _u or Al
-Si-C _u precipitates, which grows continuous film is formed. Thus low resistance, dense and flat Al-C _u or Al-
The Si-C _u film can be deposited on the substrate.

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

In the present invention, high-quality Al-C _u as a conductive deposited film
The film or Al-Si-C _u film is to use a CVD method to selectively deposited on the substrate.

That is, dimethyl aluminum hydride (DMAH) which is an organic metal is used as a source gas containing at least one atom serving as a constituent element of a deposited film. Or monomethyl aluminum hydride (MMAH ₂ ) And a gas containing Si atoms as a source gas, and H ₂ as a reaction gas, and an Al-based metal film is formed on the substrate by vapor phase growth using a mixed gas thereof.

As a substrate to which the present invention can be applied, a material having an electron donating property is used.

 This electron donating property will be described in detail below.

An electron donating material is a material in which free electrons are present in a substrate or whether free electrons are intentionally generated. For example, a chemical reaction occurs when electrons are exchanged with a source gas molecule attached to a substrate surface. A material having a surface to promote. For example, metals and semiconductors generally correspond to this. Also included are those in which a thin oxide film exists on a metal or semiconductor surface. This is because a chemical reaction occurs between the substrate and the attached raw material molecules by electron transfer.

Specifically, semiconductors such as single crystal silicon, polycrystalline silicon, and amorphous silicon, and binary systems composed of a combination of Ga, In, Al as a group III element and P, As, N as a group V element Or a ternary or quaternary III-V compound semiconductor, tungsten, molybdenum, tantalum, tungsten silicide, titanium silicide, aluminum, aluminum silicon, titanium aluminum, titanium nitride,
Includes metals such as copper, aluminum silicon copper, aluminum palladium, titanium, molybdenum silicide, tantalum silicide, alloys and silicides thereof.

Relative to the substrate in such a configuration, Al-Si-C _u or
Al-C _u is deposited only in the simple thermal reaction in the reaction system of the source gas and H _2. For example the thermal reaction in the reaction system between DMAH and H ₂ are essentially it is conceivable that. DMAH has a dimeric structure at room temperature.

Further, Si ₂ H ₆ or the like and alkyl copper compounds such as C _u (C
_{5 H 7 O 2) Al-} Si-C u or Al-C _u that is formed reached a substrate surface Si ₂ H ₂ and C _u by adding ₂ such (C ₅ H ₇ O
_{2) 2} is decomposed by the surface chemical reaction, Si and C _u is due to be taken into the film. As also shown in the Examples below by MMAH _2, high-quality Al-C _u and the thermal reaction Al-
Si- _Cu could be deposited.

MMAH ₂ has a vapor pressure as low as 0.01 to 0.1 Torr at room temperature, so it is difficult to transport a large amount of raw material. The upper limit of the deposition rate in the present invention is several hundred m / min, and preferably, the vapor pressure at room temperature is 1 Torr.
It is most desirable to use DMAH, which is r.

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 an Al-based metal film. The substrate 1 is placed on a substrate holder 3 provided inside a reaction tube 2 for forming a space for forming a deposited film which is substantially closed with respect to FIG. Quartz is preferred as a material constituting the reaction tube 2, but it may be made of metal. In this case, it is desirable to cool the reaction tube. The base holder 3 is made of metal, and is provided with a heater 4 so as to heat the mounted base. The temperature of the substrate can be controlled by controlling the heat generation temperature of the heater 4.

 The gas supply system is configured as follows.

Reference numeral 5 denotes a gas mixer, which mixes the first source gas, the second source gas, and the reaction gas and supplies them to the reaction tube 2. Reference numeral 6 denotes a source gas vaporizer provided for vaporizing 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, the carrier gas passes through the organic metal liquid into saturated vapor in the vaporizer 6 and is introduced into the mixer 5.

20 the raw material gas and the carrier gas line, 21 of the H ₂ is a reaction gas line, 22 is a line of a gas containing Si atoms to be mixed with additives, the opening and closing as required the valve (shown Z).

23 is the supply line of gas containing C _u atoms to further incorporation of further additives.

Further, the additive gas line 23, the mixer 5, and the reaction tube 2 of the present apparatus have a structure capable of heating up to 250 ° C.

 The exhaust system is configured as follows.

Reference numeral 7 denotes a gate valve which is opened when exhausting a large amount of gas, such as when exhausting the inside of the reaction tube 2 before forming a deposited film.
Reference numeral 8 denotes a slow leak valve, which is used when a small volume of gas is exhausted, for example, when adjusting the pressure inside the reaction tube 2 when forming a deposited film. Reference numeral 9 denotes an exhaust unit, which includes an exhaust pump such as a turbo molecular pump.

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

Reference numeral 10 denotes a substrate transfer chamber capable of housing a substrate before and after forming a deposited film, and is evacuated by opening a valve 11.
Reference numeral 12 denotes an exhaust unit for exhausting the transfer chamber, which is constituted by 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 a vaporizer 6 for producing a raw material gas, a liquid DMAlH
Is subjected to bubbling with H ₂ or Ar (or other inert gas) as a carrier gas to generate gaseous DMAH, which is transported to the mixer 5 via the gas line 20.
H ₂ as a reaction gas is transported from the line 21 to the mixer 5. C additive gas containing _u atom mixer via line 23 5
Transported to The additive gas containing Si atoms is transported to the mixer 5 via the line 22 as needed. The flow rate of each gas is adjusted so that its partial pressure becomes a desired value.

MMAH ₂ may be used as the first source gas, but DMAH sufficient for the vapor pressure to be 1 Torr at room temperature is most preferable.
It may also be used by mixing DMAH and MMAH _2.

As the gas containing C _u as a second raw material gas (additive gas), bis acetylacetonate copper _{C u (C 5 H 7 O} 2) 2,
Bis dipivaloylmethanato copper _{C u (C 11 H 19 O} 2) 2, bis hexafluoroacetylacetonato copper _{C u (C 5 HF 6 O} 2) 2 can be used.

Among them, it has the lowest carbon content and does not contain F
_{C u (C 2 H 7 O} 2) 2 is most preferred.

However, since the above materials are solid at room temperature and need to be transported by sublimation, the second raw material gas (added gas) line 2
3, the mixer 5 and the reaction tube 2 need to be preheated to about 180 ° C.

Further, it is more effective to flow a carrier gas of Ar or H ₂ through the second source gas line 23.

The gas containing Si as the third source gas includes Si ₂ H ₆ , SiH ₄ , Si ₃ H ₈ , Si (CH ₃ ) ₄ , SiCl ₄ , SiH ₂ Cl ₂ , SiH ₃
Cl can be used. In particular, Si ₂ H _{6 which} is easily decomposed at a low temperature of 200 to 300 ° C. is most desirable. A gas such as Si ₂ H ₆ diluted with H ₂ or Ar is transported to a mixer 5 as needed from a line 22 separate from HMAH and supplied to a reaction tube 2.

Using such source gas and reaction gas, the substrate temperature
Analysis of the film formed at 220 ° C. to 450 ° C. by Auger electron spectroscopy or photoelectron spectroscopy shows that no impurities such as carbon and oxygen are mixed in the film.

In addition, the resistivity of the deposited film is 2.7 to
3.0 μΩ · cm, which is almost equal to the resistivity of the Al bulk, is a continuous and flat film. Even if the film thickness is 1 μm, the resistivity is still approximately 2.7 to 3.0 μΩ · cm at room temperature, and a sufficiently dense film can be formed even with a thick film. The reflectance in the visible light wavelength region is also approximately 80%, and a thin film having excellent surface flatness can be deposited.

As described above, the substrate temperature is preferably equal to or higher than the decomposition temperature of the raw material gas containing Al and equal to or lower than 450 ° C. As described above, specifically, the substrate temperature is preferably 220 to 450 ° C., and deposition was performed under these conditions. If the deposition rate when DMAH partial pressure of 10 ^-4 to 10 ^-3 Torr is 400 Å / min ～1000A / min and a very large, sufficiently large deposition rate of Al-Si-C _u deposition technique for ultra-LSI can be obtained .

More preferably the substrate temperature 250 ℃ ~350 ℃, Al-Si -C u film deposited under this condition strongly oriented, and 45
Even if heat treatment is performed at 0 ° C for 1 hour, Si single crystal, Si polycrystal substrate,
Or a hillock, spike quality Al-Si-C _u film generates no on oxide film. In addition, such Al-
Si-C _u film can easily control the amount of is excellent in electro-migration resistance, and Si and C _u.

In the device of the first illustrated, it is impossible to deposit only Al-Si-C _u on one substrate in one deposition. About 800
Although a deposition rate of Å / min can be obtained, it is not sufficient for depositing a large number of sheets in a short time.

The deposited film forming device for improving this point, there is the low pressure CVD device which can deposit a large number of wafers to be simultaneously filled Al-Si-C _u. Since the Al-Si-C _u deposition according to the present invention uses a surface reaction on the heated electron donative substrate surface, Hottowooru decompression CVD the substrate is heated
If Law and DMAH and H _2, by adding a Si source gas such as _{C u (C 5 H 7 O} 2) C u material gas and Si ₂ H ₆ etc. _2, C
The _u from 0.5 to 2.0%, the Si can be deposited Al-Si-C _u film containing 0.5 to 2.0%.

Reaction tube pressure is 0.05-760 Torr, preferably 0.1-0.8 Torr
r, the substrate temperature is 220 ° C to 450 ° C, preferably 250 ° C to 400 ° C
℃, DMAWH partial pressure is 1 × 10 ^-5 times to 1.3 × 10 ^-3 times the pressure in the reaction tube.
Times, the partial pressure of _Cu (C ₅ H ₇ O ₂ ) ₂ is 5 × 10 ^-7 times the pressure in the reaction tube.
5 × 10 ^-4 times, partial pressure of Si ₂ H ₆ is 1 × 10 ^-7 times to 1 times of reactor tube pressure
× a ^10-4 times the range, Al-Si-C _u is deposited on the electron donative 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 a Al-Si-C _u or Al-C _u film. 50 is an outer reaction tube made of quartz which forms a space for forming a deposited film which is substantially closed with respect to the surroundings, and 51 is a quartz outer tube which is installed to separate a gas flow in the outer reaction tube 50. The inner reaction tube, 54 is a metal flange for opening and closing the opening of the outer reaction tube 50, and the base 57 is the inner reaction tube.
It is installed in a substrate holder 56 provided inside 51. Note that the base holder 56 is desirably made of quartz.

In addition, the present apparatus can control the substrate temperature by the heater unit 59. The pressure inside the reaction tube 50 can be controlled by an exhaust system connected via a gas exhaust port 53.

Further, the source gas has a first gas system, a second gas system, a third gas system, a fourth gas system, and a mixer, similarly to the apparatus shown in FIG. ), The source gas is introduced into the reaction tube 50 from the source gas introduction line 52. The third source gas line and the source gas introduction line 52 have a heating mechanism as in the apparatus shown in FIG. Raw material gas and the reactive gas, as shown by the second arrow in the figure 58, when passing inside inner reaction tube 51, and react at the surface of the substrate 57 is deposited on the substrate surface Al-Si-C _u. The gas after the reaction passes through a gap formed by the inner reaction tube 51 and the outer reaction tube 50, and is exhausted from the gas exhaust port 53.

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

By using such an apparatus and forming a deposited film under the conditions described above, high-quality Al-
Si-C _u film can be formed at the same time.

The Al-Si-C _u impurity content of the film is dense, such as carbon obtained by the film forming method is extremely small resistivity higher of it and surface smoothness bulk parallel characteristics based on the present invention as described above Therefore, the following remarkable effects can be obtained.

Hillock reduction Hillocks are those in which Al partially migrates when internal stress during film formation is released in a heat treatment step, and a convex portion is formed on the Al surface. A similar phenomenon also occurs due to local migration due to energization. Al-Si-C _u film formed by the present invention is in a state close to a little and monocrystalline internal stress. Therefore, while the heat treatment at 450 ° C. for 1 hour produces hillocks of 10 ⁴ to 10 ⁶ / cm ² in the conventional Al-Si film, the number of hillocks is 0 according to the present invention.
It was possible to achieve a large value of 100 pieces / cm ² . Thus, Al-Si-C
_{u Since} there are almost no surface protrusions, the thickness of the resist film and the interlayer insulating film can be reduced, which is advantageous for miniaturization and flattening.

Improvement of Electromigration Resistance Electromigration is a phenomenon in which wiring atoms move when a high-density current flows. Due to this phenomenon, voids are generated and grown along the grain boundaries, and as a result, the wiring is heated and disconnected due to a decrease in the cross-sectional area.

Generally, the migration resistance is evaluated based on the average wiring life.

The wiring according to the above-mentioned conventional method has an average wiring life of 1 × 10 ² to 10 ³ hours under the conditions of a current test of 200 ° C. and 1 × 10 ⁵ A / cm ² when the wiring cross-sectional area is 2 μm ² . Against Al-Si-C _u film obtained by Al-Si-C _u film forming method according to the present invention this, the above test, the maximum 4 × 10 wiring cross-sectional area 2 [mu] m ²
An average wiring life of ³ hours was obtained.

Improvement of contact hole and through-hole resistance and contact resistance.

When the size of the contact hole becomes as fine as 1 μm × 1 μm or less, Si in the wiring deposits on the base of the contact hole during the heat treatment in the wiring process and covers the substrate, and the resistance between the wiring and the element becomes extremely large. Become.

Since dense film is formed by the surface reaction according to the present invention the contact hole, Al-Si-C _u which is completely filled into the through-holes were confirmed to have a resistivity of 2.7～3.3Myuomegacm. The contact resistance is 0.8μm ×
1 × 10 ⁻⁶ Ω · cm ² can be achieved when the Si portion has an impurity of 10 ²⁰ cm ⁻³ in the hole of 0.8 μm.

That is, according to the present invention, the wiring material can be completely embedded in the fine holes, and good contact with the base can be obtained. Therefore, the present invention can greatly contribute to the improvement of the in-hole resistance and the contact resistance, which are the biggest problems in a fine process of 1 μm or less.

The procedure of Example 1 First Al-Si-C _u deposition is as follows. Using the apparatus shown in FIG. 1, the inside of the reaction tube 2 is evacuated to approximately 1 × 10 ⁻⁸ Torr by the exhaust equipment 9. However, even if the degree of vacuum in the reaction tube 2 is lower than 1 × 10 ⁻⁸ Torr, Al—Si—Cu is formed.

After cleaning the Si wafer, the transfer chamber 10 is released to the atmospheric pressure, and the Si wafer is loaded into the transfer chamber. The transfer chamber is evacuated to approximately 1 × 10 ⁻⁶ Torr, and then the gate valve 13 is opened to mount the wafer on the wafer holder 3.

After mounting the wafer on the wafer holder 3, the gate valve
13 is closed and the chamber 2 is evacuated until the degree of vacuum in the reaction chamber 2 becomes approximately 1 × 10 ⁻⁸ Torr.

In this embodiment, DMAH is supplied from the first gas line.
Carrier gas DMAH line with H _2. The second gas line is for H ₂ , the third gas line is for _Cu (C ₅ H ₇ O ₂ ) ₂ , and the fourth gas line is for Si ₂ H ₆ . Also, the third gas line, the mixer and the reaction tube are preheated to 180 ° C ± 10 ° C.
Set to.

Flow H ₂ from the second gas line and use the slow leak valve 8
The pressure inside the reaction tube 2 is adjusted to a predetermined value by adjusting the opening of the reaction tube 2.
The typical pressure in this embodiment is approximately 1.5 Torr. Thereafter, the heater 4 is energized to heat the wafer. After the wafer temperature has reached a predetermined temperature, DMAH _{line, C u (C 5 H 7} O 2) 2
Line, Si ₂ H ₆ DMAH the _{line, C u (C 5 H 7} O 2) and _2, Si ₂ H ₆ is introduced into the reaction tube. The total pressure is approximately 1.5 Torr, and the DMAH partial pressure is approximately 1.5 × 10 ⁻⁴ Torr. The partial pressure of _Cu (C ₅ H ₇ O ₂ ) ₂ is 1 × 10 ⁻⁶ Torr, and the partial pressure of Si ₂ H ₆ is 1 × 10 ⁻⁵ Torr. Si ₂ H ₆
When introducing DMAH into the reaction tube 2 and the Al-Si-C _u is deposited.
After a predetermined deposition time has elapsed, stops DMAH, the supply of _{C u (C 5 H 7 O} 2) 2 and Si ₂ H _6. Next, heating of the heater 4 is stopped, and the wafer is cooled. After the supply of H ₂ gas is stopped and the inside of the reaction tube is evacuated, the wafer is transferred to a transfer chamber, and only the transfer chamber is brought to atmospheric pressure, and then the wafer is taken out. The above is the outline of Al-Si-C _u deposition procedure.

 Next, preparation of a sample in this embodiment will be described.

Si substrates (N type 1～2Omucm) hydrogen combustion method (H _2: 3M,
O ₂ : 2 / M) at 1000 ° C. for thermal oxidation.

Providing a wafer with the oxide film, the total pressure 1.5 Torr DMAH partial pressure _{^{1.5 × 10 -4 Torr C u (}} C 5 H 7 O 2) 2 partial pressure _{^{1 × 10 -6 Torr Si 2 H}} 6 minutes according to the procedure described above the pressure 1 × 10 ^-5 Torr becomes Al-Si-C _u film under conditions to 5000Å is deposited, using conventional photolithographic techniques, to leave the Al-Si-C _u the width of 2,4,6Myuemu, Patterning was performed.

Table 1 Evaluation of when the line width of the evaluation and Al-Si-C _u of the deposition substrate temperature (Ts) films deposited by changing the changing
Shown in

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

Also, the patterning of the Al-Si-C _u was also very good.

(Example 2) was deposited Al-Si-C _u film in the same manner on the substrate as in Example 1 with the following settings using the apparatus shown in Figure 2.

Total pressure 1.5 Torr DMAH partial pressure 5 × 10 ^-4 Torr Si ₂ H ₆ partial pressure 1 × 10 ^-5 Torr _Cu (C ₅ H ₇ O ₂ ) ₂ partial pressure 1 × 10 ^-6 Torr Substrate temperature 300 ℃ Result , flat with excellent migration resistance in the same manner as in example 1, dense Al-Si-C _u film was obtained.

(Example 3) The total pressure is set to 1.5 Torr DMAH partial pressure 5 × 10 ^-4 Torr Si ₂ H ₆ partial pressure 1 × 10 ^-5 Torr The substrate temperature (Tsub) is set to 300 ° C. _u (C ₅ H ₇ O ₂ ) ₂ partial pressure from 5 × 10 ^-7 Torr to 1 ×
Deposition was carried out at 10 ^-4 Torr. Al- formed
Si-C _u C _u content in the film (wt%) is C _u to 4% from 0.3%
(C ₅ H ₇ O ₂ ) ₂ Changed by partial pressure. With respect to resistivity, carbon content, average wiring life, deposition rate, and hillock density, the same results as in Example 1 were obtained. But more than 3% of C _u
The sample with the content had worse surface morphology.

Example 4 Total pressure 1.5 Torr DMAH partial pressure 5 × 10 ⁻⁴ Torr _Cu (C ₅ H ₇ O ₂ ) ₂ partial pressure 1 × 10 ⁻⁶ Torr Substrate temperature (Tsub) Set to 300 ° C. and increase the partial pressure of Si ₂ H ₆ from 1.5 × 10 ⁻⁷ Torr to 1 × 10 ⁻⁴ Torr
The deposition was performed by changing to Si content of Al-Si-C _u film formed (wt%) was changed by Si ₂ H ₆ partial pressure up to 5% 0.005%. With respect to resistivity, average wiring life, deposition rate, and hillock density, the same results as in Example 1 were obtained. However, a sample having a Si content of 4% or more has
Presumed precipitates are generated and the surface morphology deteriorates,
The reflectance became 65% or less. The reflectance of the sample having a Si content of less than 4% was 80 to 95%, which was the same as in Example 1.

(Example 5) By the same procedure as in Example 1, total pressure 1.5 Torr DMAH partial pressure 5 × 10 ^-4 Torr _Cu (C ₅ H ₇ O ₂ ) ₂ partial pressure 1 × 10 ^-6 Torr Substrate temperature 300 ° C. The deposition was performed without setting Si ₂ H ₆ at all. C _u content of Al-C _u film formed in Example 1 above results in evaluation of electromigration resistance was 0.5% was obtained.

(Example 6) By the same procedure as in Example 1, total pressure 1.5 Torr DMAH partial pressure 5 × 10 ^-4 Torr Si ₂ H ₆ 1 × 10 ^-5 Torr _Cu (C ₁₁ H ₁₉ O ₂ ) ₂ partial pressure 1 × set to 10 ^-6 Torr was performed deposition of Al-Si-C _u.

Example 1 In the temperature range of the substrate temperature of 220 ° C. to 400 ° C.,
Like the flat excellent in migration resistance, the Al-Si-C _u film having excellent denseness obtained.

(Example 7) Total pressure 1.5 Torr DMAH partial pressure 5 × 10 ^-4 Torr Si ₂ H ₆ partial pressure 1 × 10 ^-5 Torr _Cu (C ₅ HF ₆ O ₂ ) ₂ minutes in the same procedure as in Example 1. set the pressure 1 × 10 ^-6 Torr was performed deposition of Al-Si-C _u.

Example 1 In the temperature range of the substrate temperature of 220 ° C. to 400 ° C.,
Like the flat excellent in migration resistance, the Al-Si-C _u film having excellent denseness obtained.

Similarly to Example 8 Example 2 was formed configuration of the base Al-Si-C _u film as described below with reference to low pressure CVD device shown in Figure 2.

Phosphorus of 10 ²⁰ cm ^-3 is selectively diffused on the surface of the single-crystal silicon, a thermally oxidized SiO ₂ film is formed thereon, and patterning is performed by a general photolithography process to partially cover the single-crystal silicon surface. Exposed.

At this time, the thickness of the thermally oxidized SiO ₂ film was 7000 °, and the size of the exposed portion of single crystal silicon, that is, the size of the opening was 0.8 μm × 0.8 μm. Thus, a sample was prepared.

Taking these samples reduced pressure CVD device shown in FIG. 2, it was deposited Al-Si-C _u film in the same badge. The film forming conditions were as follows: reactor pressure 0.3 Torr, DMAH partial pressure 3.0 × 10 ⁻⁵ Torr, Si ₂ H ₆ partial pressure 1.0 × 10 ⁻⁶ Torr, _Cu (C ₅ H ₇ O ₂ ) ₂ partial pressure 1 × 10 ^{− 7} Torr, substrate temperature 300 ° C, film formation time 10 minutes.

Deposition result in such conditions, the contact resistance between the Al-Si-C _u films deposited with phosphorus diffused region of the silicon is ^{8 × 10 -7 ~1.2 × 10 -6} Ω · cm 2 was obtained . That without installing the via metal or the like in the via hole, could be in the via holes are filled with deposited Al-Si-C _u and obtain a good contact resistance and the Hall resistance.

As has been described [Effects of the Invention According to the present invention, low resistivity, dense and flat Al-Si-C _u and Al-C _u film could be deposited on a substrate.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a deposited film forming apparatus to which the present invention can be applied, and FIG. 2 is a schematic view 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 ... Source 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: Raw material gas introduction line, 53: Gas exhaust port, 54: Metal flange, 56: Base holder, 57: Base, 58: Gas flow, 59: Heater.

──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Kazuaki Omi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shigeyuki Matsumoto 3-30-2 Shimomaruko, Ota-ku, Tokyo (56) References JP-A-1-198475 (JP, A) JP-A-55-67135 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C23C 16 / 00-16/56

Claims (2)

(57) [Claims] 1. A substrate having a surface made of a material selected from tungsten, molybdenum, tantalum, aluminum, aluminum silicon, titanium aluminum, titanium nitride, copper, aluminum silicon copper, aluminum palladium, and titanium, or a silicide thereof. Arranging a gas of dimethylaluminum hydride and / or monomethylaluminum hydride and hydrogen gas into the space for forming a deposited film, preheating a gas containing copper atoms, A step of introducing into a space for forming a deposited film, and maintaining the surface temperature within a range of 250 ° C. or more and 350 ° C. or less, containing 0.5 to 2.0% of copper, and having a hillock number of 100 / cm ^2.
A method for forming a deposited film, comprising the step of forming the following aluminum film on the surface. 2. A substrate having a surface selected from a material selected from tungsten, molybdenum, tantalum, aluminum, aluminum silicon, titanium aluminum, titanium nitride, copper, aluminum silicon copper, aluminum palladium and titanium or a silicide thereof. Arranging a gas of dimethyl aluminum hydride and / or monomethyl aluminum hydride and silicon comprising one kind of silicon hydride, alkylated silicon, silicon halide, halogenated hydride or silicon; Introducing a gas containing hydrogen and a gas containing hydrogen into the space for forming the deposited film; preheating a gas containing copper atoms to introduce the gas into the space for forming the deposited film; and 250 ° C. or more and 350 ° C. or less Within the range of the surface Maintaining the degree, it comprises silicon 0.5 to 2.0%, copper 0.5 to 2.0%
A method for forming a deposited film, comprising a step of forming an aluminum film having a hillock number of 100 / cm ² or less on the surface.