JPH09143737A - Film forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film forming apparatus capable of forming aluminum films into which additives are incorporated by a CVD treatment with good mass productivity. SOLUTION: This apparatus has a treating vessel 24 constituted to allow evacuation to vacuum, a stage 32 housed in this treating vessel 24 for placing a work W thereon, a heating means 40 for heating this stage to a film forming temp., a treating gas supplying system for supplying the treating gas for film formation formed by vaporization of a DMAH liquid to the treating vessel 24 and an additive gas supplying system for supplying the additive gasses to the treating vessel 24. The treating gas and the additive gas are introduced from both supplying systems into the treating vessel and the CVD aluminum films into which the additives are incorporated are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus for forming an aluminum film on a target object such as a semiconductor wafer by CVD.

[0002]

2. Description of the Related Art In general, a semiconductor device tends to have a multilayer wiring structure in response to recent demands for higher density and higher integration. In this case, a lower device and an upper aluminum wiring are required. Embedding technology such as a contact hole as a connection portion with the via and a via hole as a connection portion between the lower aluminum wiring and the upper aluminum wiring has become important in order to make an electrical connection between them. For burying the contact holes and via holes, it is preferable to use an inexpensive material having good conductivity, for example, aluminum. Regarding the film formation of aluminum, in order to prevent the generation of voids and to maintain high mass productivity, it is not a film formation by sputtering having a high directionality, but a CVD (C
chemical Vapor Deposition)
Film formation is desired.

In order to form an aluminum-CVD film, DMAH which is an organic metal gas is generally used as a processing gas.
(Dimethylaluminum hydride) is used, but this DMAH has a very high viscosity of about 8000 cp (centipoise) at room temperature and has a syrup-like form, and moreover, it reacts violently with moisture and oxygen in the air and ignites. It is a very difficult substance to handle. Therefore, at present, a mass-produced aluminum-CVD film forming technique has not been sufficiently developed, and the optimum process temperature and process pressure are being sought, and an optimum value has not been found. For example, when an aluminum-CVD film is formed on a trial basis in the past, the resistivity of bulk aluminum is about 2.7 μΩ · cm, whereas the aluminum-CV film has a resistivity of about 2.7 μΩ · cm.
The resistivity of the D film has a large value of about 3.5 μΩ · cm or more, and it cannot be used as a wiring material of a highly integrated semiconductor device.

Therefore, in the past, a tungsten film, which has a slightly higher electric resistance than aluminum but is excellent in mass productivity since the CVD film forming technique has been established, has been conventionally used for filling contact holes and via holes. There is. FIG. 5 shows an example of the step of filling the contact hole. First, as shown in FIG.
There is a first aluminum layer 4 formed by sputtering on top of which a SiO ₂ insulating film 6 is formed, for example, and a contact hole 8 is formed in part of this insulating film 6.

First, when tungsten and aluminum come into direct contact with each other, the contact resistance increases due to the sucking effect generated between the two. To prevent this, a barrier metal 10 made of, for example, TiN is formed on the entire surface (FIG. 5B).
Are formed in advance, the portions other than the barrier metal in the holes are removed by etching, and a tungsten film 12 is formed thereon by, for example, CVD to fill the holes (FIG. 5).
(C)). Next, except the tungsten embedded in the holes is removed by etching (FIG. 5D), and the second aluminum layer 14 is formed on the entire surface by sputtering.
As a result, the first aluminum layer 4 and the second aluminum layer 14 are electrically connected via the barrier metal 10 and the tungsten film 12 of the contact hole. Here, not only an aluminum target but also, for example, a copper target is used when the first and second aluminum layers 4 and 14 are formed by sputtering, and a small amount of an additive such as copper is contained in these layers. It is mixed. As described above, the reason for mixing the additive such as copper is that if the wiring is made of pure aluminum, a current flows in the wiring to cause Al atoms to move, that is, so-called electromigration occurs, which causes disconnection. Since it easily occurs, the additive is added as described above in order to suppress this electromigration.

As described above, since the CVD aluminum film forming technique in which the additive is mixed has not been sufficiently established in the related art, the barrier metal film formation or the tungsten film formation as described above is performed to fill the holes. Since complicated steps such as film formation and etching must be incorporated, it is strongly desired to establish an Al-CVD film formation technique which can be mass-produced and in which additives can be mixed in order to avoid the complicated steps. Is the current situation. The present invention has been devised in view of the above problems and effectively solving them. An object of the present invention is to provide a film forming apparatus capable of forming an aluminum film containing an additive by a CVD process with high mass productivity.

[0007]

In order to solve the above problems, the present invention provides a processing container which can be evacuated, and a mounting table which is housed in the processing container for mounting an object to be processed. And heating means for heating the mounting table to a film forming temperature,
A processing gas supply system for supplying a processing gas for film formation formed by vaporizing a DMAH liquid to the processing container, and an additive gas supply system for supplying an additive gas to the processing container are configured. It is a thing.

In such an apparatus, an object to be processed is placed and held on a mounting table, and the DMAH vaporized from the processing gas supply system in a state where the object is heated and maintained at the film forming temperature by the heating means.
As the processing gas, and the additive gas is supplied into the processing container from the additive gas supply system to perform the film forming process. In this case, the introduction part of each gas supply system has a common shower head structure, so that both gases can be uniformly diffused and mixed, and the uniformity of film formation characteristics can be ensured accordingly. You can As an additive, it is common to use copper for an aluminum film,
This additive gas can be produced by heating and evaporating solid CpCuTEP (cyclopentadienyl copper (II) triethylphosphine adduct) at room temperature. Therefore, the additive gas supply system is a solid CpCu.
An additive storage container for storing the TEP, a container heating means for heating and vaporizing the TEP, and a gas transfer passage for transferring the generated additive gas are provided to efficiently generate the additive gas. There is. The generated additive gas can be transported to the processing container by using a carrier gas that is not reactive with the additive gas. Further, by providing a passage heater to the entire gas transfer passage to heat the gas flowing through the passage heater, it is possible to prevent the gas from condensing.

By using such an apparatus to form an aluminum film to which an additive, for example, copper is slightly added, by CVD, an Al-CVD film having a resistivity of 3.2 μΩ · cm or less and good characteristics is formed. Can be obtained. In this case,
If the temperature of the object to be processed at the time of film formation is lower than 180 ° C., countless unevenness is generated on the surface of the film formation, the surface condition is deteriorated, and the film formation rate is also extremely reduced.
If the temperature exceeds 0 ° C, the resistivity rises sharply and cannot be used as wiring. The process pressure during film formation is 0.
The range of 5 Torr to 100 Torr is good, 0.5
If it is less than Torr, the film formation rate becomes insufficient, and
When it exceeds 100 Torr, the characteristics of the film formation are deteriorated and the surface condition of the film formation is also deteriorated.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a film forming apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. 1 is an overall configuration diagram showing a film forming apparatus according to the present invention, and FIG. 2 is a configuration diagram showing a film forming apparatus main body of the film forming apparatus shown in FIG. In this embodiment, an example will be described in which a metal aluminum film to which a small amount of copper is added as an additive is formed by CVD.

As shown in FIG. 1, the CVD film forming apparatus 16 includes a film forming apparatus main body 18 that actually performs a film forming process.
By vaporizing a DMAH (dimethylaluminum hydride) liquid in the main body 18, a processing gas supply system 20 for supplying a processing gas for forming the formed film, and an additive gas containing an additive such as copper are formed into the film. It has an additive gas supply system 22 for supplying it to the apparatus main body 18. First,
The film forming apparatus body 18 will be described with reference to FIG. As shown in the figure, the film forming apparatus main body 18 has a processing container 24 formed of, for example, aluminum in a cylindrical shape, and a feed line insertion hole 28 is provided at the center of a bottom portion 26 of the processing container 24. An exhaust port 30 that is formed and is connected to a vacuum pump (not shown) is provided in the peripheral portion, so that the inside of the container can be vacuumed.

A disk-shaped mounting table 32 made of, for example, alumina is provided in the processing container 24, and a cylindrical leg portion 34 extending downward is integrally formed at the center of the lower surface of the mounting table 32. The lower end of the leg portion 34 is attached to the periphery of the power feed line insertion hole 28 of the container bottom portion 26 and the seal member 3 such as an O-ring.
6 is interposed and fixed airtightly using bolts 38 and the like.

A resistance heating element 40 made of, for example, carbon coated with SiC is embedded as heating means on the entire upper surface of the mounting table 32, and a semiconductor as an object to be processed mounted on the upper surface side. The wafer W can be heated to a desired temperature. A thin ceramic electrostatic chuck 42 having a conductive plate (not shown) such as copper embedded therein is provided on the upper surface of the mounting table 32. Due to the Coulomb force generated by the electrostatic chuck 42,
The wafer W is sucked and held on this upper surface.
Instead of the electrostatic chuck 42, a mechanical clamp may be used to hold the wafer W. An insulated lead wire 44 is connected to the resistance heating element 40,
The lead wire 44 is drawn out through the inside of the cylindrical leg portion 34 and the power feed wire insertion hole 28, and is connected to the power feed portion 48 via the open / close switch 46. In addition, the electrostatic chuck 4
An insulated lead wire 50 is connected to a conductive plate (not shown) of FIG. 2, and the lead wire 50 is also pulled out to the outside through the inside of the cylindrical leg portion 34 and the power feed line insertion hole 28, and via the open / close switch 52. Connected to the high voltage DC power supply 54.

A plurality of lifter holes 56 are vertically penetrated at predetermined positions around the mounting table 32 and the electrostatic chuck 42, and the lifter holes 56 can be vertically moved up and down. A wafer lifter pin 58 is housed, and when the wafer W is loaded or unloaded, the lifter pin 58 is moved up and down by a lift mechanism (not shown) to lift or lower the wafer W. Generally, three such wafer lifter pins 58 are provided so as to correspond to the peripheral portion of the wafer.

A ceiling plate 62 integrally provided with a shower head structure 60 is provided at the ceiling of the processing container 24.
The shower head structure 60 is airtightly mounted via a seal member 64 such as a ring, and the shower head structure 60 is provided so as to face substantially the entire upper surface of the mounting table 32. The shower head structure 60 is for introducing a mixed gas of the processing gas and the additive gas into the processing container 24 in a shower shape, and is for ejecting the mixed gas onto the ejection surface 66 on the lower surface of the shower head structure 60. A large number of injection holes 68 are formed.

The shower head structure 60 is provided on the ceiling plate 62.
A process gas introducing port 70 for introducing a process gas and an additive gas introducing port 72 for introducing an additive gas are provided side by side, and each of the introducing ports 70, 72 has a gas supply passage 74 through which the process gas flows and an additive gas. Gas passage 7
6 are connected to each other. In the shower head structure 60, for the purpose of sufficiently mixing and diffusing the processing gas and the additive gas supplied from the respective passages 74 and 76, the first gas is provided so as to face the respective introduction ports 70 and 72. A diffusion plate 78 and a second diffusion plate 80 located below the diffusion plate 78 are provided. A large number of diffusion holes 82 are formed in each of the diffusion plates 78 and 80.
By passing the two gases through, the two gases are sufficiently mixed and dispersed. The distance L between the lower surface of the shower head structure 60 and the mounting table 32 is about 3
It is set to about 0 mm.

Further, a cooling jacket 84 is provided on the side wall of the processing container 24 to cool the wall surface, for example, a coolant, and hot water of about 50 ° C., for example, is used as a coolant. A gate valve 86 that is opened and closed when loading and unloading the wafer W is airtightly attached to a part of the side wall of the container 24. A processing gas supply system 20 for supplying a processing gas and an additive gas supply system 22 for supplying an additive gas to the film forming apparatus main body 18 configured as described above are shown in FIG. The system 20 will be described. Here, liquid high viscosity DM
The case where the AH liquid is vaporized and used as a processing gas will be described as an example. The DMAH is, as described above,
At room temperature, it has a high viscosity of about 8,000 cp and is in the form of a starch syrup. It is also highly reactive and reacts violently with oxygen and moisture in the air, while at temperatures above approximately 100 ° C. it undergoes thermal decomposition and metal aluminum precipitates. It is extremely difficult to handle.

Although the direct method is used for vaporizing the DMAH liquid,
In order to pump highly viscous DMAH, DMA is used here.
Liquid H is heated to a predetermined temperature to reduce its viscosity and make it easier to flow. In FIG. 1, a liquid storage container 88 stores a liquid DMAH 90, and the entire container is stored in an oven 92 at a temperature at which DMAH lowers its viscosity and at a temperature at which it does not thermally decompose, for example, 50.
It is heated to about 0 ° C., which reduces the viscosity to about 2000 cp and facilitates flow. This oven 92
The temperature is controlled by the temperature controller 93 so as to maintain the above-mentioned 50 ° C. The lower end of the storage container 88 is D
A pressure feed pipe 94 is inserted at a position above the liquid level of the MAH 90. The pressure feed pipe 94 is a He gas that stores He gas, for example, as a pressure feed gas via a container opening / closing valve 96, a joint 98, and a pipe opening / closing valve 100. It is connected to the gas source 102 and, for example, at a pressure of 5 kg / cm ²
The MAH 90 can be pressurized.

Further, the storage container 88 and the film forming apparatus main body 1
8 between the processing gas introduction port 70 and the processing gas introduction port 70 (see FIG. 2)
Connected by a gas supply passage 74 through which MAH flows,
The tip of this passage 74 is a liquid DMA inside the storage container 88.
It is immersed in H90. Therefore, the liquid DMAH whose viscosity has been lowered by heating is pushed out into the gas supply passage 74 by the pressure of the pressure-fed gas and flows.
In the gas supply passage 74, from the upstream side to the downstream side, the container opening / closing valve 104, the joint 106, the first opening / closing valve 108, the liquid mass flow controller 110, the second opening / closing valve 112, the carburetor 114, and the third opening / closing. The valves 116 are sequentially provided. Therefore, the liquid DMAH pumped in the gas supply passage 74 is transferred to the liquid mass flow controller 1.
While being controlled in flow rate by 10, the gas flows into the vaporizer 114 and is vaporized into a processing gas.
8 will be supplied.

In the vaporizer 114, the carrier gas pipe 1
18 is connected, and the other end of the carrier gas pipe 118 is provided with an H ₂ gas source 120 that stores, for example, H ₂ gas as a vaporized gas and carrier gas. The H ₂ gas is supplied to the vaporizer 114 while controlling the flow rate by the mass flow controller 122. As the carrier gas, Ar gas was used instead of H ₂ gas.
Other inert gas such as gas, He gas, Ne gas may be used.

Further, a tape heater is wound around the entire gas supply passage 74 between the liquid storage container 88 and the vaporizer 114 and each member interposed therein, so that the first heating heater 124 is provided. Is provided, and the whole container 8
Liquid DM flowing at the same temperature as 8
The low viscosity of AH is maintained. Further, the vaporizer 114 and the gas supply passage 74 on the downstream side are also provided with a second heater 126 by winding a tape heater, for example, at a temperature at which the processing gas does not reliquefy, for example, 60. It is heated within the range of -80 ° C. The tape heater 128 may be wound around the carrier gas pipe 118 to heat it to 60 to 80 ° C. to preheat the carrier gas and promote the vaporization of DMAH.
The method of supplying the processing gas is not limited to the above-mentioned direct vaporization method, and a so-called bubbling method in which a bubbling gas is introduced into liquid DMAH and vaporized may be used.

Next, the additive gas supply system 22 will be described. Here, CpCuTEP (cyclopentadienyl copper (II) triethylphosphine adduct) that is solid at room temperature is heated and vaporized, and this is supplied as a gas for copper addition. CpCuTEP132, which is solid at room temperature, is stored in the additive storage container 130, and the entire container is stored in an oven 134 as a container heating means, and is heated to a temperature above the vaporization temperature of CpCuTEP132, for example, about 60 ° C. Has been done. In addition, this oven 13
The heating temperature by 4 is preferably in the range of 40 ° C. to 120 ° C., for example, when the temperature is 40 ° C. or lower, the gas generation amount is excessively small, and when the temperature is 120 ° C. or higher, CpCuTEP132 is thermally decomposed and metallic copper is deposited. The temperature of the oven 134 is controlled by the temperature controller 136 so as to maintain the above-mentioned temperature of about 60 ° C.

A carrier gas pipe 138 is inserted into the additive container 130, and this gas pipe 138 has
Connected to a H ₂ gas source 150 as a carrier gas source for storing, for example, H ₂ gas as a carrier gas through a container opening / closing valve 140, a joint 142, a first opening / closing valve 144, a mass flow controller 146 and a second opening / closing valve 148. The H ₂ gas whose flow rate is controlled can be introduced into the additive container 130. Incidentally, the H ₂ gas source 150, the previous processing gas supply system 20 H ₂
It may be shared with the gas source 120. Further, the additive storage container 130 and the additive gas introduction port 72 (see FIG. 2) of the film forming apparatus main body 18 are connected by a gas transfer passage 76 through which an additive gas flows. In the gas transfer passage 76, a container opening / closing valve 152, a joint 154, a first opening / closing valve 156, a mass flow controller 158, and a second opening / closing valve 160 are sequentially provided from the upstream side toward the downstream side. Therefore, the Cp generated in the container 130
A CuTEP gas, that is, an additive gas is carried by a carrier gas of H ₂ gas and is supplied to the film forming apparatus main body 18 while the flow rate is controlled by the mass flow controller 158.

Also in this case, the carrier gas is H
Instead of the ₂ gas, another inert gas such as Ar gas, He gas, Ne gas may be used. Then, a tape heater is wound around the entire gas transfer passage 76 and each member interposed therebetween, for example, by heating the passage heater 16.
2 is provided, and the whole is heated to a temperature equal to or higher than the condensation temperature of the additive gas, for example, about 60 ° C., so that the flowing additive gas is prevented from condensing and flows smoothly. The heating temperature of the heater 162 is preferably set in the range of 40 ° C to 80 ° C in consideration of the condensation temperature and the thermal decomposition temperature.

Next, the operation of the apparatus configured as above will be described. First, an unprocessed wafer W is loaded into the processing container 24 via the opened gate valve 86 using a transfer arm (not shown), the wafer is received by the wafer lifter pin 58, and the wafer W is lowered to lower the mounting table. Three
2 The wafer W is firmly held by the Coulomb force generated by the electrostatic chuck 42. Then, by driving the exhaust system, the inside of the processing container 24 is evacuated to the base pressure and the resistance heating element 40 is energized to bring the wafer W into a predetermined process temperature range, for example, 18
Predetermined value within the range of 0 ℃ to 250 ℃, eg 200 ℃
To maintain. Then, the processing gas supplied from the processing gas supply system 20, that is, the gas of the DMAH liquid and the additive gas containing copper supplied from the additive gas supply system 22 are supplied to the shower head structure 60 to be mixed, While introducing this mixed gas from the shower head structure 60 into the processing container 24, the inside of the processing pressure range, for example, 0.5 to 100 T.
A CVD film formation of copper-added aluminum is performed while maintaining a predetermined value within the range of orr, for example, about 2 Torr. In order to suppress the electromigration of aluminum, the content of copper is 0.5% to 10% by weight.
%, And preferably about 1%.

Here, a gas supply method will be described.
First, in order to supply the processing gas, the oven 92 is used to heat and maintain the liquid storage container 88 and the DMAH 90 at about 50 ° C., and as described above, the DMAH 90, which has a high viscosity at room temperature, is reduced to a viscosity of about 2000 cp to facilitate the flow. In this state, for example, 5 kg / cm via the pressure feeding pipe 94.
By introducing the He gas having a pressure of ² into the container, the liquid DMAH is pushed out and flows into the gas supply passage 74 at this pressure, and the liquid mass flow controller 11
It is introduced into the vaporizer 114 while its flow rate is controlled by 0. Then, the liquid DMAH in the vaporizer 114 is
H ₂ which is a carrier gas supplied from the H ₂ gas source 120 while the flow rate is controlled by the mass flow controller 122.
_The gas is vaporized by the _two gases and becomes a processing gas, flows through the gas supply passage 74 as it is, reaches the film forming apparatus main body 18, and is introduced into the shower head structure 60 from the processing gas introduction port 70.

In this case, the liquid storage container 88 is removed from the vaporizer 1
The temperature of the gas supply passage 74 up to 14 and the members interposed therein are the temperatures at which the liquid DMAH is not thermally decomposed by the first heater 124 and the viscosity can be kept low, that is, the same temperature as the storage container 88, For example, since it is heated to 50 ° C., the viscosity of the liquid DMAH flowing therethrough is maintained in a low state and smoothly flows, so that a sufficient amount of DMAH required for mass-production level film formation is obtained. It can be supplied to the vaporizer 114 while controlling the flow rate with high accuracy.
Further, the processing gas generated by vaporizing liquid DMAH with H ₂ gas in the vaporizer 114 further flows toward the downstream in the gas supply passage 74.
The temperature of the gas supply passage 74 on the downstream side of this and the members interposed therein, at which the second heater 126 does not thermally decompose DMAH and maintains the vaporized state, for example, 60
Since it is heated within the range of -80 ° C, the processing gas flowing therethrough is smoothly transported without being reliquefied and is supplied into the showerhead structure 60 as described above.

On the other hand, in order to supply the additive gas, the additive accommodating container 130 is set to CpCu by the oven 134.
A temperature above the vaporization temperature of TEP and at which it does not thermally decompose,
For example, in the present embodiment, the solid CpCuTEP132 contained therein is heated to about 100 ° C. and vaporized to generate an additive gas. At the same time, from the carrier gas source 150, the H ₂ gas whose flow rate is controlled by the mass flow controller 146 is introduced as a carrier gas into the container 130, and the additive gas generated here is accompanied by this carrier gas and is passed through the gas transfer passage. The mass flow controller 158 flows through the mass flow controller 158 while controlling the flow rate, reaches the film forming apparatus main body 18, and is introduced into the shower head structure 60 by the additive gas introduction port 72. in this case,
By the passage heater 162, the gas transfer passage 76 and each member interposed therewith have a predetermined value within a temperature range where the additive gas is not recondensed and thermally decomposed, for example, a range of 40 ° C. to 80 ° C., For example, since the heating is maintained at about 60 ° C., the additive gas smoothly flows without recondensing. Here, the content of Cu in the aluminum film formation is an amount capable of sufficiently suppressing electromigration, for example, 0.5% by weight or more, particularly preferably set to 1% or more, and 10%. If it exceeds, the effect of suppressing electromigration will be saturated.

Therefore, the flow rates of the processing gas and the additive gas are
During the aluminum film formation, the flow rate is controlled so that the Cu content falls within the above range. The additive gas and the processing gas supplied as described above are effectively diffused in the showerhead structure 60, uniformly mixed and injected into the processing space, and Cu is added to the wafer surface as described above. The Al-CVD film is formed.

In this case, the process temperature is 180 ° C. to 250 ° C. as a film forming condition for the CVD-Al film to which copper is added.
It is better to set it within the range of
If the temperature is lower than 0 ° C, numerous irregularities are formed on the surface of the Al film, the surface condition is deteriorated, so-called morphology is deteriorated, and the film formation rate is also extremely reduced, which is not preferable. Further, if the temperature exceeds 250 ° C. and becomes too high, the resistivity rapidly rises and the characteristics deteriorate, so that it cannot be used as a wiring. The process pressure during film formation is preferably in the range of 0.5 Torr to 100 Torr,
If it is less than 0.5 Torr, the film forming rate becomes very low and not sufficient, and if it exceeds 100 Torr, the film forming characteristics are deteriorated and the surface condition of the film forming is also deteriorated to deteriorate the morphology. .

Further, the larger the amount of the gas DMAH as the processing gas, the better, and in particular, the higher the flow rate, the more the increase in the process temperature can suppress the increase in the resistivity of the Al film. FIG. 3 is a graph showing the relationship between the film forming rate and the resistivity with respect to the process temperature. In the figure, black circles and white circles indicate DMAH.
20 SCCM, H ₂ gas 1000 SCCM, and a small amount of additive gas respectively, black triangles, open triangles DMAH 10 SCCM, H ₂ gas 500 SCC
The figure shows the case where a small amount of M and additive gas are supplied respectively.
As described above, the flow rate of the additive gas is Cu during the aluminum film formation.
The weight ratio is set to about 1%. still,
The process pressure at this time is 2 Torr. First, regarding the film formation rate, the higher the process temperature, the higher the film formation rate, which is suitable for mass production.
When the temperature exceeds 50 ° C. and increases, the resistivity increases beyond the limit value of 3.2 μΩ · cm that can be used as wiring, and the electrical characteristics of film formation deteriorate. The resistivity of bulk aluminum is approximately 2.7 μΩ · cm, and theoretically the resistivity does not become smaller than this value.

Further, as the process temperature decreases, the film forming speed also decreases, making it unsuitable for mass production.
When the temperature is lower than 80 ° C., it was found from a micrograph that the film-forming surface was severely roughened and the morphology was significantly deteriorated. Therefore, the process temperature is 180 ° C as described above.
It turns out that a temperature within the range of up to 250 ° C. is good. still,
In this case, it is natural that the film-forming rate increases as the supply amount of the processing gas increases, but it is revealed that the increase in the resistivity accompanying the increase in the process temperature is suppressed as the supply amount increases. . Therefore, it is desirable to increase the supply amount of the processing gas in order to suppress the increase in the resistivity. As described above, the increase in the supply amount of the processing gas is caused by the liquid DMAH as described above.
This can be realized by heating and heating the resin to reduce its viscosity to facilitate the flow, and it is possible to easily secure a flow rate of about 100 SCCM under highly accurate flow rate control.

FIG. 4 is a graph showing the relationship between the process pressure and the film formation rate. The process temperature at this time is 200.degree.
DMAH and H ₂ gas are 20 SCCM and 1000 respectively
It is an SCCM, and a small amount of additive gas is also added as described in FIG. As is clear from the graph, when the process pressure becomes lower than 0.5 Torr, the film forming rate rapidly deteriorates, which is not suitable for mass production and is not preferable. Therefore, it is found that the process pressure should be set to 0.5 Torr or more. However, the process pressure is 1
When the film formation was performed with the setting larger than 00 Torr, the microscopic photograph showed that the surface of the film was severely roughened and the morphology was deteriorated.

In the above embodiment, the additive storage container 13 is used.
Although an oven was used as the container heating means 134 for heating 0, the present invention is not limited to this, and a thermostat or the like may be used. Furthermore, in the above embodiment, CpCu
Although the case where copper is added using TEP has been described as an example, other additives such as CpCuTMP may be used instead.
(Cyclopentadienyl copper (II) trimethylphosphine adduct: C ₅ H ₅ CuP (CH ₃ ) ₃ ) and the like may be added. Further, although the semiconductor wafer is described as an example of the object to be processed in the above embodiment, the present invention is not limited to this, and it is needless to say that it can be applied to the case of forming a film on another object to be processed, for example, an LCD substrate or a glass substrate. Is.

[0035]

As described above, according to the film forming apparatus of the present invention, the following excellent operational effects can be exhibited. Since a processing gas supply system for vaporizing and supplying DMAH and an additive gas supply system for supplying an additive gas are provided, it is possible to mass-produce a metal aluminum film containing additives with good characteristics by CVD film formation. Can be formed with. Therefore, the contact holes, the via holes, etc. can be filled with the aluminum film by CVD, and the manufacturing process can be greatly simplified.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a film forming apparatus according to the present invention.

2 is a configuration diagram showing a film forming apparatus main body of the film forming apparatus shown in FIG.

FIG. 3 is a graph showing a relationship between a film forming rate and a resistivity with respect to a process temperature.

FIG. 4 is a graph showing the relationship between process pressure and film formation rate.

FIG. 5 is an explanatory diagram for explaining a hole embedding process.

[Explanation of symbols]

16 film forming apparatus 18 film forming apparatus main body 20 processing gas supply system 22 additive gas supply system 24 processing container 32 mounting table 40 resistance heating element (heating means) 74 gas supply passage 76 gas transfer passage 88 liquid storage container 90 DMAH 102 He Gas source 130 Additive storage container 132 CpCuTEP 134 Oven (container heating means) 150 H ₂ gas source (carrier gas source) 162 Passage heater W W Semiconductor wafer (object to be processed)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 21/3205 H01L 21/88 N

Claims (5)

[Claims] 1. A processing container that can be evacuated, a mounting base that is housed in the processing container for mounting an object to be processed, and a heating unit that heats the mounting base to a film forming temperature.
A processing gas supply system for supplying a processing gas for film formation formed by vaporizing a DMAH liquid to the processing container; and an additive gas supply system for supplying an additive gas to the processing container. Film forming apparatus. 2. The film forming method according to claim 1, wherein the processing gas supply system and the additive gas supply system have a shower head structure in common with a gas introduction portion to the processing container. apparatus. 3. The additive gas supply system is solid CpC
an additive container for containing uTEP (cyclopentadienyl copper (II) triethylphosphine adduct);
By heating this storage container, the CpCuTEP
A container heating means for vaporizing and generating an additive gas,
The film forming apparatus according to claim 1 or 2, comprising a gas transfer passage for transferring the generated additive gas toward the processing container. 4. The film forming apparatus according to claim 3, wherein the gas transfer passage is provided with a passage heater for preventing condensation of the additive gas flowing therein. 5. The film forming apparatus according to claim 1, wherein the additive gas supply system has a carrier gas source that stores a carrier gas for transporting the additive gas.