JP2003119564A - Film-forming method and plasma cvd apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film-forming method which can continuously perform removal of a natural oxide film formed on the surface of a substrate and deposition of a film containing a high melting metal, in the same chamber in a short time without exposing the substrate to the air, and to provide a plasma CVD apparatus. SOLUTION: This film forming method comprises removing the natural oxide film existing in the surface of the Si-substrate, in the chamber of the plasma CVD apparatus, and then forming the film containing the high melting metal on the Si-substrate, from which the natural oxide film has been continuously removed in the same chamber in which etching and film-forming conditions are optimized, without exposing the Si-substrate to the air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming method and a plasma CVD apparatus, and more particularly to a process for removing a natural oxide film formed on a Si substrate, a film containing a refractory metal and a refractory metal nitride on the Si substrate. The present invention relates to a film forming method and a plasma CVD apparatus for continuously performing a film forming process in the same chamber.

[0002]

2. Description of the Related Art In a conventional semiconductor manufacturing process, first, a natural oxide film (SiO 2
₂ ) Remove. Since a natural oxide film of 30 to 40 Å is formed on the surface of the Si substrate in a normal room temperature environment, a film containing a refractory metal or a refractory metal nitride film, that is, a Ti thin film or a TiN thin film is formed on the Si substrate. The Si oxide film is previously immersed in a dilute hydrofluoric acid (DHF) solution to remove the natural oxide film.

Next, a film containing a refractory metal is formed on the Si substrate after the natural oxide film is removed by chemical vapor deposition (CVD). Forming a film containing a refractory metal on a Si substrate is
This is to ensure normal conductivity. That is, when the W (tungsten) or Al alloy layer which is the wiring portion is directly provided on the Si substrate, the W of the tungsten layer easily reacts with the Si substrate and thus easily diffuses, forming a high resistance substance such as WSi. Since a normal conductivity cannot be ensured, in order to prevent this, a refractory metal film in which Si and a good resistance material are difficult to form is provided between the Si substrate and the Al alloy layer to ensure normal conductivity. To secure the sex.

FIG. 5 is a sectional view showing the overall structure of a conventional plasma CVD apparatus.

This apparatus has an airtight, substantially cylindrical chamber 101, in which a susceptor 102 for horizontally supporting a Si substrate W to be processed is provided.
Are arranged. Heater 103 for susceptor 102
Is embedded, and this heater 103 has a power source 104
Power is supplied to heat the susceptor 102 to heat the Si substrate W, which is the object to be processed, to a predetermined temperature.

A shower head 130 is provided on the ceiling wall 101a of the chamber 101 via an insulating member 105. On the upper surface of this shower head 130, TiC
A first inlet 106 for introducing l ₄ and a second inlet 107 for introducing H ₂ as a reducing gas are formed. First inlet 106 is connected with a number of TiCl ₄ passages 108 which is branched inside the shower head 130, TiCl ₄ passages 108 T
It is connected to the iCl ₄ discharge hole 109. The second inlet 107 is connected with a number of H ₂ passage 110 which is branched inside the shower head 130, H ₂ passage 1
Reference numeral 10 is connected to the H ₂ discharge hole 111. Therefore, the shower head 130 is of a matrix type in which TiCl ₄ and H ₂ are independently supplied into the chamber 101 so that TiCl ₄ and H ₂ are not mixed, and these are mixed after the discharge and a reaction occurs.

A valve 11 is provided at the first inlet 106.
5 and mass flow controller 116 through TiCl
₄ source 112 and Ar source 113 are connected, TiC
The TiCl ₄ gas from the l ₄ source 112 is carried by the Ar gas from the Ar source 113 and supplied into the chamber 101. Above the second introduction opening 107, source of H ₂ 114 through a valve 115 and a mass flow controller 116 is connected, H ₂ gas from the source of H ₂ 114 is supplied to the chamber 101. Although not shown,
A line for supplying N ₂ gas is also provided in the chamber 101.

The shower head 130 includes a matching unit 117.
And a high frequency power supply 118 is connected via a matcher 121 for controlling the frequency, and high frequency power is supplied from the high frequency power supply 118 to the shower head 130 and applied to the shower head 130 via the matcher 121 to supply the chamber 101. The gas supplied into the inside is turned into plasma, whereby the film forming reaction proceeds.

An exhaust device 120 is connected to the bottom wall 101b of the chamber 101 via an exhaust pipe 119.
By operating the exhaust device 120, the inside of the chamber 101 can be depressurized to a predetermined degree of vacuum.

In order to form a Ti thin film on the Si substrate W using such an apparatus, first, the heater 103 heats the susceptor 102 to a predetermined temperature while the exhaust device 120 exhausts the inside of the chamber 101, followed by Ar gas. And H ₂ gas are introduced into the chamber 101 at a predetermined flow rate ratio to make the chamber 101 have a predetermined pressure and
High frequency power is supplied from the high frequency power supply 118 to the shower head 130 to generate plasma in the chamber 101.

Next, in a plasma state in which the flow rates of Ar gas and H ₂ gas are maintained, a predetermined flow rate of TiCl 4 gas is supplied to the inner wall of the chamber 101 or the interior of the chamber such as the shower head 130 arranged in the chamber 101. Precoat the surface of the material. At this time, the Si substrate W is not inserted in the chamber.

After that, the Si substrate W is inserted into the chamber, the susceptor 102 is heated by the heater 103, the Si substrate W is heated to a predetermined temperature, the gas under the same conditions as the precoat is supplied, and the Ti thin film is formed. Membrane treatment is performed for a predetermined time. The Ti thin film forming process at this time is performed at a temperature of 600 ° C., for example.

Next, after the Ti thin film is formed, the TiN thin film is formed. In this TiN thin film forming process,
Since the flow rate and the type of gas used in the Ti thin film forming process are different, the Si substrate W after the Ti thin film forming process is inserted into another chamber to perform the TiN thin film forming process.
Here, Ti, which is a barrier metal, is further formed on the Ti thin film.
The N thin film is formed by forming a W (tungsten) or Al alloy layer, which is a wiring member, on the Ti thin film.
Alternatively, this is because Al forms an alloy with Al, or W or Al diffuses into Si, which accelerates the deterioration of the electrodes and forms high-resistance WSi, AlSi, or the like, which makes it impossible to obtain high contact resistance. The TiN thin film is formed to block the diffusion of W or Al into Si.

The plasma CVD apparatus shown in FIG.
A plasma CVD apparatus is known which includes one high-frequency power source, but includes two high-frequency power sources in order to perform a film forming process at a higher plasma density (JP 2000-178A).
749 publication).

[0015]

However, according to the above-mentioned prior art, the natural oxide film on the surface of the Si substrate W is removed, the film containing the refractory metal is formed, and the refractory metal nitride film is formed. When the film processing is executed, each time one processing is completed, the Si substrate W is placed in the chamber and the Si substrate W is taken out from the chamber. Therefore, these operations require a certain time. And then S
The i-substrate W is exposed to the atmosphere, which causes a problem that a natural oxide film is formed on the substrate surface.

The present invention has been made in view of the above circumstances, and removes the natural oxide film formed on the surface of the substrate and the film forming process of a film containing a refractory metal, and the substrate is exposed to the atmosphere. An object of the present invention is to provide a film forming method and a plasma CVD apparatus which can be continuously executed in the same chamber in a short time without exposing.

[0017]

In order to achieve the above object, the film forming method according to claim 1 is a film forming method for forming a film on a substrate by using a plasma CVD apparatus. A natural oxide film removing step of removing a natural oxide film on the surface of the substrate in the chamber, and the same chamber optimized for etching and film formation without exposing the substrate from which the natural oxide film is removed to the atmosphere 2. The step of continuously forming a film containing a refractory metal on the substrate from which the natural oxide film has been removed.

According to a second aspect of the present invention, there is provided a film forming method of forming a film on a substrate by using a plasma CVD apparatus, wherein a natural oxide film on the surface of the substrate is formed in a chamber of the plasma CVD apparatus. The step of removing the natural oxide film and the step of removing the natural oxide film on the substrate from which the natural oxide film has been removed in the same chamber optimized for etching and film formation without exposing the substrate from which the natural oxide film has been removed to the atmosphere. A step of continuously forming a film containing a refractory metal, and a step in which the etching and the film formation are optimized in the same chamber without exposing the substrate on which the film containing a refractory metal is formed to the atmosphere. And a step of continuously forming a refractory metal nitride film on the film containing the refractory metal.

According to a third aspect of the film forming method, an etching gas for removing a natural oxide film on the surface of the substrate is provided in a chamber for mounting the substrate, and the etching gas for removing the natural oxide film is provided on the substrate. A gas supplying step for supplying a film forming gas for forming a film containing a melting point metal; a first high frequency power outputting step for outputting a high frequency power for converting the etching gas into a plasma; and a high melting point metal containing step. A second high-frequency power output step of outputting high-frequency power for forming a film; and a control step of controlling on / off of the first high-frequency power output step and the second high-frequency power output step, the gas comprising: In the supplying step, when the natural oxide film is removed, the etching gas is supplied into the chamber, and when the film containing the refractory metal is continuously formed in the same chamber, the above-mentioned deposition is performed. Gas supply, in said control step,
When removing the native oxide film, the first high frequency power output step is turned on, the second high frequency power output step is turned off, and a film containing the refractory metal is continuously formed in the same chamber. At the time, the first high frequency power output step is turned off, and the second high frequency power output step is turned on.

According to a fourth aspect of the present invention, there is provided a film forming method, wherein an etching gas for removing a natural oxide film on a surface of the substrate is placed in a chamber in which the substrate is placed, and a high gas is deposited on the substrate from which the natural oxide film is removed. A gas supply step of supplying a film forming gas for forming a film containing a melting point metal and a high melting point metal nitride film; and a first high frequency power output step of outputting high frequency power for converting the etching gas into plasma. A second high frequency power output step of outputting high frequency power for converting the film forming gas into plasma, and a control step of controlling ON / OFF of the first high frequency power output step and the second high frequency power output step. In the gas supplying step, when the natural oxide film is removed, the etching gas is supplied into the chamber to continuously form a film containing the refractory metal in the same chamber. At that time, the film forming gas is supplied, and when the high melting point metal nitride film is continuously formed in the same chamber, the film forming gas is supplied, and in the control step, the natural oxide film is formed. When removing, the first high frequency power output step is turned on, the second high frequency power output step is turned off, and when the film containing the refractory metal is continuously formed in the same chamber, the first high frequency power output step is turned on. When the first high frequency power output step is turned off, the second high frequency power output step is turned on, and the refractory metal nitride film is continuously formed in the same chamber, the first high frequency power output step is turned off. And turning on the second high frequency power output step.

A film forming method according to a fifth aspect is the film forming method according to any one of the first to fourth aspects, further comprising a heating step of heating the substrate during the etching and the film formation. Is characterized by.

A film forming method according to claim 6 is the film forming method according to any one of claims 1 to 5, wherein the substrate is S.
i, CoSi ₂ , W, WSi, Ni, NiSi, Mo,
The film made of MoSi, Cu or Al and containing the refractory metal is a thin film of Ti, TiSi or Ta.

A film forming method according to claim 7 is the film forming method according to claim 2 or 4, wherein the refractory metal nitride film is Ti.
It is characterized by being a thin film of N, TaN or WN.

In the plasma CVD apparatus according to the present invention, an etching gas for removing a natural oxide film on the surface of the substrate is provided in a chamber for mounting the substrate, and the etching gas for removing the natural oxide film is provided on the substrate. A gas supply means for supplying a film forming gas for forming a film containing a melting point metal; a first high frequency power output means for outputting high frequency power for converting the etching gas into plasma; and a high melting point metal. A second high-frequency power output means for outputting high-frequency power for forming a film; and a control means for controlling ON / OFF of the first high-frequency power output means and the second high-frequency power output means. The supplying means supplies the etching gas into the chamber when removing the natural oxide film, and continuously forms a film containing the refractory metal in the same chamber. When the film forming gas is supplied, the control unit turns on the first high frequency power output unit and turns off the second high frequency power output unit when removing the natural oxide film, and the same chamber is continuously supplied. When the film containing the refractory metal is formed inside, the first high frequency power output means is turned off and the second high frequency power output means is turned on.

The "substrate" described in claims 1 to 8 is not limited to one composed of pure chemical substances such as Si, but various thin films are formed on Si, for example. Also included are those which are generally called substrates in the process of manufacturing, distribution or sales.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A plasma CVD apparatus and a film forming method according to embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the overall structure of a plasma CVD apparatus according to an embodiment of the present invention.

This apparatus has a substantially cylindrical chamber 11 which is hermetically sealed, in which a susceptor 12 for horizontally supporting a substrate W to be processed is a cylindrical supporting member. It is arranged so as to be supported by 13. Here, the substrate W is made of Si, CoSi ₂ , W, WSi,
Although it may contain Ni, NiSi, Mo, MoSi, Cu, Al, or the like, the substrate W is hereinafter referred to as a Si substrate W made of Si.

A guide ring 16 for guiding the Si substrate W is provided on the outer edge of the susceptor 12.
Further, a heater 14 is embedded in the susceptor 12, and the heater 14 is supplied with power from a power source 15 and heats the susceptor 12 so that the Si substrate W which is the object to be processed.
Is heated to a predetermined temperature. Furthermore, the susceptor 12 has an S
Electrode plate 50 for generating plasma in chamber 11 to remove the native oxide film on the surface of i substrate W
Is embedded in the electrode plate 50, and the switch 4
A high-frequency power source 49 is connected via 7 and a matching unit 48. The output frequency of this high frequency power source 49 is 13.56M.
Hz.

A shower head 20 is provided on the ceiling wall 11a of the chamber 11 via an insulating member 19.
The shower head 20 is composed of an upper block body 20a, an intermediate block body 20b, and a lower block body 20c.
_A first inlet 21 for introducing ₄ and Ar, and a second inlet 22 for introducing H ₂ as a reducing gas and NH ₃ used in the film forming process of the TiN thin film are formed. ing. In the upper block body 20a, a plurality of passages 23 branch from the first introduction port 21, the passages 23 communicate with the passages 25 formed in the middle block body 20b, and further in the lower block body 20c. It communicates with the discharge hole 27 through the passage 26. In addition, the upper block body 20
In a, a large number of passages 24 branch from the second introduction port 22, the passages 24 communicate with passages 26 formed in the middle block body 20b, and further the lower block body 2
It communicates with the discharge hole 28 via the passage 26 of 0c. That is, the shower head 20 uses TiCl ₄ and Ar, and H ₂
And NH ₃ are of a matrix type that are independently supplied into the chamber 11 so as not to mix with each other, and these are mixed after the discharge to cause a reaction.

A TiCl ₄ source 3 is supplied to the first inlet 21.
1 and the pipe 32 is connected which extends from the pipe 32 have pipe 36 extending from the Ar source 35 as a carrier gas is connected, TiCl ₄ gas from the TiCl ₄ source 31 is supplied through a pipe 36 Ar It is carried by the gas and supplied into the chamber 11 through the pipe 32. Also,
A pipe 54, from which a ClF ₃ source 53 extends, is connected to the pipe 32, and a film-forming substance (Ti,
ClF ₃ gas for removing TiN) is supplied into the chamber 11 via the pipe 32. Above the second inlet 22 is connected to a line 38 extending from the source of H ₂ 37, H ₂ gas from the source of H ₂ 37 is supplied into the chamber 11 via a pipe 38. Further, a pipe 34 extending from the NH ₃ source 33 and the N ₂ source 51 is connected to the pipe 38 via a switching valve 41, and NH ₃ gas and N ₂ are supplied into the chamber 11 via the pipe 34 and the pipe 32. It is possible to supply gas. The pipes 32, 34, 36, 38 from each gas source are provided with valves 39, 41 and a mass flow controller 40, respectively.

A high frequency power source 43 is connected to the shower head 20 via a switch 46 and a matching unit 42. By supplying high frequency power from the high frequency power source 43 to the shower head 20, the shower head 20 is passed through. As a result, the gas supplied into the chamber 11 is turned into plasma, and the film formation process is thereby advanced. The output frequency of the high frequency power source 43 is 450 KHz.

An exhaust pipe 44 is connected to the bottom wall 11b of the chamber 11, and the exhaust device 4 is connected to the exhaust pipe 44.
5 is connected. By operating the exhaust device 45, the inside of the chamber 11 can be depressurized to a predetermined degree of vacuum.

On / off control of the switches 46 and 47 is performed by the control device 52 provided in the plasma CVD apparatus.

FIG. 2 is a diagram showing a schematic configuration of a circuit of the plasma CVD apparatus of FIG.

The plasma CVD apparatus according to the present invention requires a chamber having a structure that lowers the plasma impedance. This is to maintain stable plasma even when the power and voltage of the high frequency power supplies 43 and 49 are low, and to enable etching and film formation processing.

As shown in the figure, the upper electrode (shower head 20) has a matching network circuit 210 for stably generating plasma and a Vdc monitor circuit (2).
01-203) is connected to the rectifier. In the Vdc monitor circuit (201 to 203), one end of the capacitor 201 is grounded and the other end is connected to one end of each of the coil 202 and the resistor 203. The other end of the coil 203 is connected to the power supply voltage Vdc,
The power supply voltage Vdc can be monitored. Next, the matching network circuit 210 is connected to the shower head 20 via the blocking capacitor 204. The other end of the blocking capacitor 204 is connected to one ends of the coil 207 and the variable capacitor 205, and the other end of the variable capacitor 205 is grounded via the coil 206. The other end of the coil 207 is connected to the high frequency power supply 43 via the variable capacitor 208 and the resistor 209, and the other end of the high frequency power supply 43 is grounded. The matching network 210 having such a configuration is a so-called plasma impedance matching device, and the impedance when plasma is formed and after the plasma is formed, that is, the impedance from the rectifier to the electrode (plasma impedance) and the rectifier to the high frequency power supply 43. It has a function to automatically adjust the matching with the impedance up to so that no reflected wave is generated.

Next, the lower electrode (electrode plate 50) is connected to the matching network circuit 222 and V similarly to the upper electrode.
A rectifier composed of a dc monitor circuit (211 to 213) is connected. Vdc monitor circuit (211-2)
13), one end of the capacitor 211 is grounded and the other end is connected to one end of each of the coil 212 and the resistor 213. The other end of the resistor 213 has the power supply voltage Vdc.
The power supply voltage Vdc can be monitored. Next, the matching network circuit 222 is connected to the lower electrode included in the susceptor 12 via the blocking capacitor 214. At the other end of the blocking capacitor 214, the capacitor 215 and the coil 2 having a circuit configuration that allows etching to be performed at a low pressure in consideration of a high plasma impedance.
17 is connected. The other end of the capacitor 215 is grounded via the coil 216. Next, the coil 217
The other end of is connected to the high frequency power supply 49 via the variable capacitor 218 and the resistor 221, and the other end of the high frequency power supply 49 is grounded. The other end of the coil 217 is connected to the variable capacitor 21 for applying a bias voltage to the lower electrode.
It is connected to the coil 220 via 8, 219, and the other end of the coil 220 is grounded.

With the above circuit structure, etching and film formation can be performed by applying a bias to the lower electrode.

Next, the relationship between the plasma impedance and the area of the electrode plates and the distance between the electrode plates will be described.

When the electrode area of the electrode plate 50 is A and the distance between the electrode plates is l, the vacuum impedance C ₀ between the electrode plates is C ₀ = ε ₀ A / l (ε ₀ : vacuum). Dielectric constant of).

Therefore, the plasma impedance Zc of the plasma becomes Zc = 1 / jωC ₀ = 1 / jωε ₀ A (jω: constant).

As a result, the plasma impedance Zc
Becomes smaller as the electrode plate area A becomes larger or the inter-electrode plate distance l becomes smaller.

The advantage of reducing the plasma impedance Zc is that, when the current I (t) or the voltage V (t) of the same value is supplied between the electrode plates, the high frequency power is lower than that when the plasma impedance Zc is large. Is enough. In other words, when high frequency power of the same value is supplied, a larger value of current I (t) or voltage V (t) can be supplied between the electrode plates as compared with the case where the plasma impedance Zc is large. , Tentatively, plasma impedance Z
A stable plasma can be maintained even when c takes a large value.

In this embodiment, for example, the upper electrode plate area is 700 cm ² (diameter = 300 mm) and the lower electrode plate area is 346 cm ² (diameter = 210 mm).
That is, the area ratio of the upper plate to the lower plate is 1 or more 5
It is below, preferably 1.5 or more and 3 or less.

The distance l between the electrode plates is, for example, 13.5.
Although it is mm, it may be a value of 5 to 30 mm, and more preferably a value of 5 to 15 mm.

FIG. 3 is a flow chart showing a film forming method according to the embodiment of the present invention, showing a process up to forming a film containing a refractory metal and a refractory metal nitride film on a Si substrate W. . FIG. 4 shows the state of the Si substrate W and the ON / OFF state of the switches 46 and 47 corresponding to the steps of the flowchart of FIG.
It is a figure which shows an off state.

First, the inside of the chamber 11 is evacuated by the exhaust device 45 while heating the inside of the chamber 11 by the heater 14 of the plasma CVD apparatus shown in FIG.
H ₂ gas is introduced into the chamber 11 and the chamber 1
While setting the pressure in 1 to 0.5 to 20 mTorr,
The switch 47 is turned on so that the shower head 20 is supplied with 200 to 1000 W from the high frequency power source 49, more preferably 2
The high frequency power of 0 to 500 W is supplied to the chamber 1
A plasma is generated within 1. At this time, the switch 46 is off, and high frequency power is not supplied from the high frequency power supply 43 to the shower head 20.

Plasma is generated in the chamber 11.
And Ar gas and Ar ions and H ₂Gas to H ion
And the Ar ions are attracted to the Si substrate W side.
The native oxide film on the Si substrate is etched by Ar ions.
And removed (step S1). Ar ion
Contributes to etching and plasma stability, and H ions are natural
Oxide film (SiO₂) Acts as a reducing agent.

The conditions for this natural oxide film removal treatment are Ar.
The flow rate of gas is 1 to 80 sccm (more preferably 4 to 6 sccm).
0 sccm) (more preferable values are written in parentheses in the following description), and the flow rate of H ₂ gas is 1 to 160 sccc.
m (1 to 80 sccm), the pressure in the chamber 11 is 0.05 to 1 Torr (5 to 20 mTorr), and the high frequency power supplied to the electrode plate 50 is 200 to 10
00W (200 to 500W), the temperature in the chamber 11 is 200 to 500 ° C, and the treatment time is 5 to 18
It is 0 sec (10 to 60 sec).

Then, after the natural oxide film is removed in step S1, the chamber 14 is heated by the heater 14 while the Si substrate W is still mounted on the susceptor 12 in the chamber 11.
While heating the inside of the chamber 1 to 600 ° C., the inside of the chamber 11 is evacuated by the exhaust device 45, and for example, the flow rate is 1 to 10 scc.
m of TiCl ₄ gas, Ar gas having a flow rate of 1 to 20 sccm, and H ₂ gas having a flow rate of ₂ to 30 sccm.
And a pressure of 1 to 10 Torr in the chamber 11, a bias voltage is applied to the lower electrode (electrode plate 50), and the switch 46 is turned on and the switch 47 is turned off to shower from the high frequency power source 43. High-frequency power of 200 to 700 W is supplied to the head 20, plasma is generated in the chamber 11, and a Ti thin film forming process is performed for 30 to 60 seconds (step S2). Simultaneously with the formation of the Ti thin film, Si of the substrate W and Ti react with each other to form a TiSi film (film containing a refractory metal). The bias voltage is applied to the lower electrode is TiC.
It is easier to draw the lx molecule into the hole,
This is because it is possible to bring about an effect of facilitating the film formation of i, that is, improving the bottom coverage, and it is particularly effective when the aspect ratio is as high as 5 or more.

After the Ti thin film is formed in step S2, the inside of the chamber 11 is heated to 400 to 700 ° C. by the heater 14 while the Si substrate W is still mounted on the susceptor 12 inside the chamber 11. Exhaust device 45
The chamber 11 is evacuated by the flow rate of 5 to 50 sc
cm TiCl ₄ gas, flow rate 50-1000 sccm
(100-500 sccm) NH ₃ gas, flow rate 30-
200 sccm (30 to 100 sccm) N ₂ gas and flow rate 100 to 3000 sccm (800 to 2000 s)
Ccm) H ₂ gas is introduced into the chamber 11 to cause the inside of the chamber 11 to be 0.1 to 10 Torr (0.3 to 3 Tor).
rr), the switch 46 is turned on, the switch 47 is turned off, and high-frequency power of 500 W is supplied from the high-frequency power source 43 to the shower head 20 to generate plasma in the chamber 11 to generate TiN thin film. The film forming process is performed for 10 to 300 sec (30 to 120 sec) (step S3), and the process until the film containing the refractory metal and the refractory metal nitride film is formed is completed. In addition, TiN
A bias voltage may be applied to the lower electrode also in the thin film forming process.

When this process is completed, the T
An i thin film (a film containing a refractory metal) is formed, and at the same time, Si and Ti of the substrate W undergo a mutual diffusion reaction to form a TiSi film (a film containing a refractory metal).
An iN thin film (high melting point metal nitride film) is formed.

As described above, according to this embodiment,
After the natural oxide film on the surface of the Si substrate W is removed in the chamber 11 of the plasma CVD apparatus, the same etching and film formation are optimized without exposing the Si substrate W from which the natural oxide film is removed to the atmosphere. Since a film containing a refractory metal is continuously formed on the Si substrate W from which the native oxide film has been removed in the chamber 11 of FIG. The film formation process can be continuously performed in the same chamber in a short time without exposing the substrate to the atmosphere.

Further, without exposing the substrate on which the film containing the refractory metal is formed to the atmosphere, the film containing the refractory metal is continuously formed on the film in the same chamber optimized for etching and film formation. Since the melting point metal nitride film is formed, the removal process of the natural oxide film formed on the substrate surface and the film formation process of the film containing the refractory metal and the refractory metal nitride film can be performed without exposing the substrate to the atmosphere. , Can be continuously executed in the same chamber in a short time.

In step S3 of FIG. 3 described above, the TiN thin film forming process is executed by plasma CVD, but instead of this, the TiN thin film forming process may be executed by thermal CVD.

That is, after the Ti thin film forming process in step S2 of FIG. 3, the temperature of the chamber 11 is kept at 400 to 700 ° C. by the heater 14 while the Si substrate W is still mounted on the susceptor 12 in the chamber 11. The chamber 11 is evacuated by the evacuation device 45 while heating, and the flow rate is 5 to 50.
sccm TiCl ₄ gas, flow rate 50-1000 scc
NH ₃ gas of m (100 to 500 sccm) and flow rate 3
N ₂ gas of 0 to 200 sccm (30 to 100 sccm) is introduced into the chamber 11, the pressure in the chamber 11 is set to 0.1 to 10 Torr (0.3 to 3 Torr), and the switch 46 and the switch 47 are turned off. Heater 14 without supplying any high frequency power.
The TiN thin film is formed by heating for 10 to 30
It may be performed for 0 sec (30 to 120 sec).

In this case, the switch 46 is turned off,
The switch 47 is turned on, plasma is generated to remove the natural oxide film, and thereafter, T
i Gas for forming thin film is supplied, switch 46 is turned on and switch 47 is turned off to form Ti thin film, and further gas for forming TiN thin film in the same chamber 11 Is supplied, the switches 46 and 47 are turned off, and no high frequency power is supplied,
Since the TiN thin film is formed by heating with the heater 14, the natural oxide film formed on the substrate surface is removed and the film containing the refractory metal and the refractory metal nitride film are exposed to the atmosphere. It can be continuously executed in the same chamber in a short time without exposing.

In the above embodiment, the refractory metal nitride film is formed by plasma CVD and thermal CVD.
The film may be formed by (physical vapor deposition method).

In the above-mentioned embodiment, the Ti thin film is taken as an example of the film containing the refractory metal, but it may be a Ta thin film, a TiSi thin film or a TaSi thin film. Furthermore, although the TiN thin film is given as an example of the refractory metal nitride film, it may be a TaN or WN thin film.

[0061]

As described above in detail, according to the film forming method of the first aspect, the natural oxide film formed on the surface of the substrate is removed and the film containing the refractory metal is formed. It is possible to continuously perform the processing in the same chamber in a short time without exposing the substrate to the atmosphere.

According to the film forming method of the second aspect, the natural oxide film formed on the surface of the substrate is removed, and the film containing the refractory metal and the refractory metal nitride film are formed. It can be continuously executed in the same chamber in a short time without being exposed to.

According to the film forming method of the third aspect and the plasma CVD apparatus of the eighth aspect, the etching gas is turned into plasma and the natural oxide film formed on the surface of the substrate is etched. Further, a film containing a refractory metal is continuously formed in the same chamber. Therefore, the removal process of the natural oxide film formed on the substrate surface and the film containing the refractory metal are
It is possible to continuously perform the processing in the same chamber in a short time without exposing the substrate to the atmosphere.

According to the film forming method of the fourth aspect, the etching gas is turned into plasma and the natural oxide film formed on the substrate surface is etched. Further, a film containing a refractory metal is continuously formed in the same chamber. Further, a refractory metal nitride film is continuously formed in the same chamber. Therefore, the removal process of the natural oxide film formed on the substrate surface and the film formation process of the film containing the refractory metal and the film of the refractory metal nitride are continuously performed in the same chamber without exposing the substrate to the atmosphere. Can be run in time.

According to the film forming method of claim 5, thermal CV is used.
A film containing a refractory metal or a refractory metal nitride film can be formed by D.

[Brief description of drawings]

FIG. 1 is a sectional view showing an overall configuration of a plasma CVD apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a circuit of the plasma CVD apparatus of FIG.

FIG. 3 is a flowchart showing a film forming method according to an embodiment of the present invention.

FIG. 4 is an S corresponding to steps in the flowchart of FIG.
It is a figure which shows the state of i board | substrate W, and the ON / OFF state of switch 46,47.

FIG. 5 is a cross-sectional view showing the overall configuration of a conventional plasma CVD apparatus.

[Explanation of symbols]

11 chambers 12 susceptor 14 heater 15 power supply 20 shower head 42,48 Matching device 43,49 high frequency power supply 45 Exhaust device 46,47 switch 50 electrode plate

Claims (8)

[Claims] 1. A film forming method for forming a film on a substrate using a plasma CVD apparatus, comprising a step of removing a natural oxide film on a surface of the substrate in a chamber of the plasma CVD apparatus. When,
A film containing a refractory metal continuously on the substrate from which the native oxide film has been removed in the same chamber optimized for etching and film formation, without exposing the substrate from which the native oxide film has been removed to the atmosphere. And a step of forming a film. 2. A natural oxide film removing step of removing a natural oxide film on a surface of the substrate in a chamber of the plasma CVD apparatus in a film forming method for forming a film on a substrate by using a plasma CVD apparatus. When,
A film containing a refractory metal continuously on the substrate from which the native oxide film has been removed in the same chamber optimized for etching and film formation, without exposing the substrate from which the native oxide film has been removed to the atmosphere. And the step of forming the film containing the refractory metal in the same chamber optimized for etching and film formation without exposing the substrate on which the film containing the refractory metal is formed to the atmosphere. And a step of continuously forming a refractory metal nitride film. 3. A chamber containing a substrate is provided with an etching gas for removing a natural oxide film on the surface of the substrate, and a film containing a refractory metal is formed on the substrate from which the natural oxide film is removed. A gas supplying step for supplying a film forming gas for forming a film, a first high frequency power outputting step for outputting a high frequency power for converting the etching gas into plasma, and a film for forming a film containing the refractory metal. A second high-frequency power output step of outputting high-frequency power; and a control step of controlling on / off of the first high-frequency power output step and the second high-frequency power output step, wherein the natural oxidation is performed in the gas supply step. When the film is removed, the etching gas is supplied into the chamber,
When the film containing the refractory metal is continuously formed in the same chamber, the film forming gas is supplied, and in the control step, when the natural oxide film is removed,
When the first high frequency power output step is turned on, the second high frequency power output step is turned off, and the film containing the refractory metal is continuously formed in the same chamber, the first high frequency power output step is performed.
A high-frequency power output step is turned off, and the second high-frequency power output step is turned on. 4. An etching gas for removing a natural oxide film on a surface of the substrate in a chamber for mounting the substrate, and a film containing a refractory metal and a high temperature gas on the substrate from which the natural oxide film is removed. A gas supplying step of supplying a film forming gas for forming the melting point metal nitride film, a first high frequency power outputting step of outputting a high frequency power for converting the etching gas into a plasma, and a plasma forming of the film forming gas. A second high-frequency power output step of outputting high-frequency power for converting the first high-frequency power output step and a control step of controlling on / off of the first high-frequency power output step and the second high-frequency power output step, in the gas supply step Supplying the etching gas into the chamber when removing the natural oxide film,
When the film containing the refractory metal is continuously formed in the same chamber, the film forming gas is supplied, and when the refractory metal nitride film is continuously formed in the same chamber, The film forming gas is supplied, and in the control step, when removing the natural oxide film,
When the first high frequency power output step is turned on, the second high frequency power output step is turned off, and the film containing the refractory metal is continuously formed in the same chamber, the first high frequency power output step is performed.
The high frequency power output step is turned off, the second high frequency power output step is turned on, and when the refractory metal nitride film is continuously formed in the same chamber, the first high frequency power output step is turned off. A film forming method, wherein the second high frequency power output step is turned on. 5. The film forming method according to claim 1, further comprising a heating step of heating the substrate when performing the etching and the film formation. 6. The substrate is Si, CoSi ₂ , W, WS
6. The film made of i, Ni, NiSi, Mo, MoSi, Cu or Al, and the film containing a refractory metal is a thin film of Ti, TiSi or Ta. 7. Film forming method. 7. The refractory metal nitride film is made of TiN or TaN.
Or a thin film of WN.
The film forming method described. 8. An etching gas for removing a natural oxide film on a surface of the substrate in a chamber for mounting the substrate, and a film containing a refractory metal is formed on the substrate from which the natural oxide film is removed. Gas supply means for supplying a film forming gas for forming a film, first high frequency power output means for outputting a high frequency power for converting the etching gas into plasma, and for forming a film containing the refractory metal A second high-frequency power output means for outputting high-frequency power; and a control means for controlling on / off of the first high-frequency power output means and the second high-frequency power output means, wherein the gas supply means comprises the natural oxidation When the film is removed, the etching gas is supplied into the chamber,
When the film containing the refractory metal is continuously formed in the same chamber, the film forming gas is supplied, and the control means outputs the first high frequency power output when removing the natural oxide film. Turning on the means, turning off the second high frequency power output means, and turning off the first high frequency power output means when continuously forming a film containing the refractory metal in the same chamber. 2. A plasma CVD apparatus characterized in that the high frequency power output means is turned on.