JP2003221671A - Gas treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas treatment method capable of reducing a metal contamination. <P>SOLUTION: This gas treatment method comprises a step of precoating a metallic film (STEP 3) on the surface of an inner wall of a chamber for accommodating a substrate to be treated and of a member in the chamber, while feeding a halogen-containing gas into the chamber, in the absent state of the substrate, a subsequent step of oxidizing the metal halide (STEP 7) present in the chamber, with an oxygen-containing gas introduced into the chamber, and a subsequent step of forming a thin film (STEP 12) on the substrate while feeding the halogen-containing gas, after carrying the substrate into the chamber. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas processing method for supplying a processing gas containing a halogen gas to a substrate to be processed such as a semiconductor wafer to perform gas processing such as film forming processing.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process,
A semiconductor wafer (hereinafter, simply referred to as a wafer) which is a substrate to be processed is subjected to various gas treatments such as film forming treatment and etching treatment. Such gas processing is performed by housing the wafer in a chamber and supplying a processing gas containing halogen such as Cl and F while reducing the pressure in the chamber.
For example, in a CVD film forming process of Ti, TiN, W, etc., a wafer is heated to, for example, about 700 ° C., a process gas is made into plasma as necessary, and a halogen-containing gas and a reducing gas as a film forming gas are formed under a predetermined reduced pressure. Etc. are introduced into the chamber to perform a film forming process. Further, in such a film forming process, prior to carrying the wafer into the chamber, a similar halogen-containing gas or the like is introduced into the chamber to pre-coat the chamber inner wall and the chamber inner member with the same substance as the film forming substance. A precoat process is performed.

However, in the gas treatment using such a halogen-containing gas, the constituent components of the Al alloy (for example, JIS A 5052) and the stainless steel constituting the inner wall of the chamber and the members such as the shower head provided in the chamber. Al, Fe, Cu or the like reacts with hydrogen halide such as HCl or HF produced as a by-product of the gas treatment, and these metal halides are produced. Further, there is a problem that such a metal halide is easily vaporized in the chamber kept under reduced pressure and diffused in the chamber to become particles in the chamber, resulting in metal contamination on the wafer.

Such metal contamination mixes with the Si diffusion layer formed at the bottom of the contact hole of the wafer and easily diffuses in Si, possibly deteriorating the transistor characteristics such as withstand voltage and ohmic resistance.

Recently, the pattern formed on the wafer has been miniaturized, and the contact hole, which was conventionally φ0.25 μm, is miniaturized to φ0.15 to 0.13 μm, and the size of Si is about 150 nm. Diffusion layer is 100-80
It is miniaturized to nm. As described above, as the junction (shallow junction) having a shallow Si diffusion layer is used, the deterioration of the transistor characteristics due to the above-mentioned metal contamination becomes remarkable, and the demand for the reduction of metal contamination is increasing more and more. It's getting stronger. The reduction of such metal contamination is
In particular, it is extremely important in metal film formation by CVD.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a gas treatment method capable of reducing metal contamination.

[0007]

In order to solve the above problems, the present invention comprises a step of supplying a gas containing a halogen element into a chamber containing a substrate to be processed and subjecting the substrate to gas treatment. A step of introducing a gas containing oxygen into the chamber to oxidize a metal halide present in the chamber while the substrate to be processed is not present in the chamber. A gas treatment method is provided.

In this case, the step of performing the gas treatment can be performed while heating the substrate to be treated and / or by converting the treatment gas into plasma. Further, the gas treatment of the present invention is preferably applied to a film forming treatment, and examples of such a film forming treatment include Ti, TiN and W film forming.

Further, according to the present invention, a gas containing a halogen element is supplied into a chamber for accommodating a substrate to be processed in a state where the substrate to be processed is not present, and a predetermined film is formed on the inner wall of the chamber and the surfaces of the members in the chamber. And a step of introducing a gas containing oxygen into the chamber to oxidize a metal halide present in the chamber, and then carrying in a substrate to be processed into the chamber, And a step of supplying a gas containing an element to form a thin film on the substrate to be processed.

According to the present invention, a gas containing oxygen is introduced into the chamber to oxidize the metal halide existing in the chamber while the substrate to be processed is not present in the chamber. Therefore, when a gas treatment such as a film formation process is subsequently performed on the substrate to be processed, it is possible to reduce the amount of easily vaporized metal halides in the chamber, and it is possible to reduce the particles in the chamber and thus the substrate to be processed. The metal contamination above can be reduced.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 shows a TiN film forming process according to an embodiment of the present invention.
It is a schematic block diagram which shows the multi-chamber type film-forming system in which the N film-forming apparatus was mounted.

As shown in FIG. 1, this film forming system 10
0 has two Ti film forming devices 1 and 2 for forming a Ti film by CVD and two TiN film forming devices 3 and 4 for forming a TiN film by CVD, for a total of four film forming devices. The film forming apparatuses 1, 2, 3 and 4 are provided corresponding to the four sides of the hexagonal wafer transfer chamber 5, respectively. Load lock chambers 6 and 7 are provided on the other two sides of the wafer transfer chamber 5, respectively. A wafer loading / unloading chamber 8 is provided on the opposite side of the load transfer chambers 6 and 7 from the wafer transfer chamber 5, and a wafer W can be accommodated on the opposite side of the wafer loading / unloading chamber 8 from the load lock chambers 6 and 7. Ports 9 and 1 for attaching the three large hoops (FOUP) F
0 and 11 are provided. The Ti film forming apparatuses 1 and 2 and the TiN film forming apparatuses 3 and 4 have the same structure.

The Ti film forming apparatuses 1 and 2, the TiN film forming apparatuses 3 and 4, and the load lock chambers 6 and 7 are connected to the respective sides of the wafer transfer chamber 5 through gate valves G, as shown in FIG. These are communicated with the wafer transfer chamber 5 by opening the gate valves G, and are shut off from the wafer transfer chamber 5 by closing the gate valves G. A gate valve G is also provided in a portion of the load lock chambers 6 and 7 connected to the wafer loading / unloading chamber 8. The load lock chambers 6 and 7 are opened / closed by opening the gate valve G. 8 and is closed from the wafer loading / unloading chamber 8 by closing them.

In the wafer transfer chamber 5, a Ti film forming apparatus 1,
2, TiN film forming devices 3 and 4, and load lock chamber 6
7, a wafer transfer device 12 for loading and unloading the wafer W, which is the object to be processed, is provided. The wafer transfer device 12 is disposed in the approximate center of the wafer transfer chamber 5,
Two blades 14a, 14b for holding the wafer W are provided at the tip of the rotating / expanding / contracting portion 13 which can be rotated and expanded / contracted. Is attached to. The inside of the wafer transfer chamber 5 is kept at a predetermined vacuum level.

A HEPA filter (not shown) is provided on the ceiling of the wafer loading / unloading chamber 8, and the clean air that has passed through the HEPA filter is supplied into the wafer loading / unloading chamber 8 in a downflow state. The wafer W is loaded and unloaded in a clean air atmosphere at atmospheric pressure. Three ports 9 and 1 for attaching the hoop F of the wafer loading / unloading chamber 8
A shutter (not shown) is provided on each of the ports 0 and 11, and an empty hoop accommodating a wafer W is directly attached to these ports 9, 10 and 11, and the shutter is removed when attached to the outside air. Of the wafer carrying-in / carrying-out chamber 8 while preventing the entry of the wafer. Also,
The alignment chamber 1 is provided on the side surface of the wafer loading / unloading chamber 8.
5 is provided, and the wafer W is aligned there.

In the wafer loading / unloading chamber 8, there is provided a wafer transfer device 16 for loading / unloading the wafer W to / from the hoop F and loading / unloading the wafer W to / from the load lock chambers 6, 7. The wafer transfer device 16 has a multi-joint arm structure, and the rail 1 is arranged along the arrangement direction of the hoops F.
The wafer W is placed on the hand 17 at the tip of the wafer 8 and is transferred.

In such a film forming system 100, first, one wafer W is taken out from any one of the FOUPs F by the wafer transfer device 16 in the wafer loading / unloading chamber 8 held in the atmospheric clean air atmosphere. Then, the wafer W is loaded into the alignment chamber 15 and the wafer W is aligned.
Next, the wafer W is loaded into one of the load lock chambers 6 and 7, the inside of the load lock chamber is evacuated, and the wafer transfer device 12 in the wafer transfer chamber 5 takes out the wafer W from the load lock chamber. W is charged into the Ti film forming apparatus 1 or 2 to form a Ti film, and the wafer W after Ti film formation is continuously inserted into the TiN film forming apparatus 3 or 4 to form a TiN film. . Wafer W after film formation
Is carried into either of the load lock chambers 6 and 7 by the wafer transfer device 12 and the inside of the load lock chamber is returned to atmospheric pressure, and then the wafer W in the load lock chamber is taken out by the wafer transfer device 16 in the wafer loading / unloading chamber 8. It is housed in one of the hoops F. Such an operation is performed on one lot of wafers W, and one set of processing is completed. By such a film forming process, as shown in FIG. 2, the contact hole 2 reaching the impurity diffusion region 20 a formed in the interlayer insulating film 21.
In FIG. 2, a Ti film 23 as a contact layer and a TiN film 24 as a barrier layer are formed. After that, another device is used to form a film of Al, W, etc., and the contact hole 2
2 is embedded and a wiring layer is formed.

Next, the TiN film forming apparatus 3 will be described. As described above, the TiN film forming apparatus 4 also has the same configuration as the TiN film forming apparatus 3. FIG. 3 is a sectional view showing a TiN film forming apparatus for carrying out the CVD film forming method according to the present invention. The TiN film forming apparatus 3 is made of aluminum and has a substantially cylindrical chamber 31 which is hermetically sealed. The chamber 31 is made of Al or stainless steel, and the chamber 31 includes a susceptor 32 for horizontally supporting a wafer W as a substrate to be processed.
Are arranged in a state of being supported by a cylindrical support member 33 provided in the lower part of the center thereof. A guide ring 34 for guiding the wafer W is provided on the outer edge of the susceptor 32.
Is provided. In addition, the susceptor 32 has a heater 3
5, the heater 35 heats the wafer W, which is the substrate to be processed, to a predetermined temperature by being supplied with power from the heater power supply 36. The susceptor 32 can be made of ceramics such as AlN. When the susceptor 32 is made of ceramics in this way, a ceramic heater is formed.

A shower head 40 is provided on the ceiling wall 31a of the chamber 31 via an insulating member 39.
The shower head 40 includes an upper block body 40a, an intermediate block body 40b, each of which is made of aluminum.
It is composed of a lower block body 40c. Then, the lower block body 40c has discharge holes 47 and 48 for discharging gas.
And are formed alternately. A first gas inlet 41 and a second gas inlet 4 are provided on the upper surface of the upper block body 40a.
2 are formed. In the upper block body 40a, a large number of gas passages 43 are branched from the first gas inlet 41. Gas passages 45 are formed in the middle block body 40b, and the gas passages 43 communicate with these gas passages 45 through horizontally extending communication passages 43a.
Further, the gas passage 45 communicates with the discharge hole 47 of the lower block body 40c. In addition, in the upper block body 40a, a large number of gas passages 44 are provided from the second gas inlet 42.
Is branched. The gas passage 4 is provided in the middle block body 40b.
6 are formed, and the gas passage 44 communicates with these gas passages 46. Further, the gas passage 46 is connected to a communication passage 46a extending horizontally in the middle block body 40b, and the communication passage 46a is connected to the lower block body 40c.
Of the discharge holes 48. And the first
The second gas inlets 41 and 42 are connected to the gas supply mechanism 5
It is connected to zero gas lines.

The gas supply mechanism 50 uses a cleaning gas.
A certain ClF_ThreeClF supplying gas _ThreeGas supply source 51,
TiCl, a Ti-containing gas_FourTiCl supplying gas
_FourGas supply source 52, N_TwoFirst N supplying gas_Twogas
Source 53 and second N_TwoGas supply source 55, NH_ThreeMoth
NH supplying gas_ThreeGas supply source 54, O_TwoSupply gas
O_TwoIt has a gas supply source 56. And ClF_Three
ClF is used as the gas supply source 51._ThreeThe gas supply line 57 is T
iCl_FourTiCl is used as the gas supply source 52._FourGas supply line
58 is the first N_TwoThe gas supply source 53 has a first N_Twogas
Supply line 59 is NH_ThreeNH for the gas supply source 54_ThreeMoth
Supply line 60 is the second N_TwoThe gas source 53 has a
2 N_TwoGas supply line 60a is O_TwoGas supply source 56
An oxygen-containing gas supply line 60b is connected to each
Has been. And each gas supply line has a mass flow
Between the controller 62 and the mass flow controller 62
Therefore, two valves 61 are provided. The first moth
TiCl in the gas inlet 41 _FourExtending from gas source 52
TiCl_FourThe gas supply line 58 is connected to this
TiCl_FourClF in the gas supply line 58_ThreeGas supply
ClF extending from 51_ThreeGas supply line 57 and first
N_TwoFirst N extending from gas source 53_TwoGas supply
The in 59 is connected. In addition, the second gas introduction
NH in the mouth 42_ThreeNH extending from gas source 54_Threegas
The supply line 60 is connected to this NH_ThreeGas supply
The second N on line 60_TwoNo. extending from gas source 55
2 N _TwoGas supply line 60a, O_TwoGas source 56
The oxygen-containing gas supply line 60b extending from the
It Therefore, during the process, TiCl_FourGas supply
TiCl from source 52_FourGas is the first N_TwoGas supply source 5
N from 3_TwoTiCl with gas_FourGas supply line 5
The first gas inlet 41 of the shower head 40 through
To the inside of the shower head 40 from the gas passages 43, 45
Through the discharge hole 47 into the chamber 31.
One, NH_ThreeNH from gas source 54_ThreeGas is the second N
_TwoN from gas source 55_TwoNH with gas_ThreeGas supply
The second of the shower head 40 is supplied via the gas supply line 60.
From the gas inlet 42 to the inside of the shower head 40,
Inside the chamber 31 from the discharge hole 48 through the passages 44 and 46
Is discharged to. That is, the shower head 40 is made of Ti
Cl_FourGas and NH_ThreeChamber 3 completely independent of gas
It is a matrix type that is supplied in 1.
These are mixed after ejection and a reaction occurs.

A high frequency power source 64 is connected to the shower head 40 via a matching unit 63, and high frequency power is supplied from the high frequency power source 64 to the shower head 40 as needed. Normally, this high frequency power supply 64 is not necessary, but if it is desired to increase the reactivity of the film forming reaction, the high frequency power supply 64 supplies high frequency power to the gas supplied into the chamber 31 via the shower head 40. It is also possible to form a film by converting into plasma.

A circular hole 65 is formed in the center of the bottom wall 31b of the chamber 31, and the bottom wall 31b is provided with an exhaust chamber 66 projecting downward so as to cover the hole 65. . An exhaust pipe 67 is connected to the side surface of the exhaust chamber 66, and an exhaust device 68 is connected to the exhaust pipe 67. By operating the exhaust device 68, the inside of the chamber 31 can be depressurized to a predetermined degree of vacuum.

The susceptor 32 is provided with three (only two are shown) wafer support pins 69 for supporting and raising and lowering the wafer W so as to project from and retract into the surface of the susceptor 32. 69 is fixed to the support plate 70. Then, the wafer support pin 69 is moved up and down via the support plate 70 by a drive mechanism 71 such as an air cylinder.

On the side wall of the chamber 31, a loading / unloading port 72 for loading / unloading the wafer W to / from the wafer transfer chamber 5.
And a gate valve 73 that opens and closes the loading / unloading port 72.

Next, the process of forming a TiN film by the TiN film forming apparatus 3 will be described with reference to the flowchart of FIG. First, in a state in which no wafer W is present in the chamber 31, a state-away pulling the inside of the chamber 31 by the exhaust device 68, the shower head 40 the N ₂ gas from the first and second N ₂ gas supply source 53 and 55 While being introduced into the chamber 31 via the heater 35, the inside of the chamber 31 is preheated by the heater 35 (S
TEP1). When the temperature becomes stable, N ₂ gas, NH ₃ gas, and T ₃ gas are supplied from the first N ₂ gas supply source 53, NH ₃ gas supply source 54, and TiCl ₄ gas supply source 52, respectively.
iCl ₄ gas is introduced at a predetermined flow rate through the shower head 40, and pre-flow is performed while maintaining the chamber internal pressure at a predetermined value (STEP 2). Then, while maintaining the same gas flow rate and pressure, the TiN film is pre-coated on the inner wall of the chamber 31 and the chamber inner members such as the shower head 40 by heating with the heater 35 (STEP).
3).

After completion of the precoat process, NH_ThreeGas and
And TiCl_FourTurn off the gas, the first and second N_Twogas
Source 53 and 55 to N_TwoGas as purge gas
Supply into the chamber 31 and purge inside the chamber 31
(STEP4), then N_TwoGas and NH_Three
Nitride on the surface of TiN thin film formed by flowing gas
Processing is performed (STEP 5). N at this time_TwoGas supply
Is the first and second N _TwoOf gas sources 53 and 55
May be sourced from either or both
You may. In addition, this nitriding process is not necessary.
Will be done.

After the nitriding process is completed, the NH ₃ gas is stopped, and N ₂ gas is supplied into the chamber 31 as a purge gas to purge the chamber 31 (STEP).
6) and then the O ₂ gas source 56 in the chamber 31
From supplying _{O 2} gas, by supplying the _{N 2} gas from the first and second _{N 2} gas supply source 53 and 55, a heater 3
The heating of 5 oxidizes the metal halide formed on the inner wall of the chamber 31 (STEP).
7). At this time, the O ₂ gas flow rate is 0.1 to 10 L / min.
Is preferable, and the total flow rate of N ₂ gas is 0.1 to 1
The range of 0 L / min is preferable. In addition, O ₂ gas and N ₂
The gas flow rate ratio O ₂ / N ₂ is preferably in the range of 1 to 10. Furthermore, the pressure in the chamber is 10-100.
It is preferable that the range is 0 Pa, the susceptor temperature is 200 to 700 ° C., and the treatment time is 10 seconds to 10 minutes.

After that, the chamber 3 is evacuated by the exhaust device 68.
The inside of 1 is rapidly evacuated to a fully cut state (STEP
8) The gate valve 73 is opened, and the wafer W is loaded into the chamber 31 from the vacuumed wafer transport chamber 5 by the wafer transport device 12 through the loading / unloading port 72 (STE).
P9). Then, N ₂ gas is supplied into the chamber 31 to preheat the wafer W (STEP 10). When the temperature became stable, N ₂ gas, NH ₃ gas and TiCl _{4 were} added.
Gas is introduced at a predetermined flow rate through the shower head 40,
Pre-flow is performed while maintaining the chamber internal pressure at a predetermined value (STEP 11). Then, while maintaining the same gas flow rate and pressure, the wafer 35 is heated by the heater 35 to form a TiN film on the wafer W (STEP 12).
In this film forming process, TiN in the range of 5 to 100 nm is used.
A film is deposited. Since the film thickness is proportional to the film forming time, the film forming time is appropriately set according to the desired film thickness. That is, the film thickness at the time of film formation can be adjusted by the film formation time within the above range of 5 to 100 nm. For example, the film thickness is 20 nm
If it is set to, it is carried out for 35 seconds. The heating temperature of the substrate at this time is about 400 to 700 ° C, preferably about 600 ° C. At the time of this film formation, the high frequency power source 64 is not always necessary.
It is not necessary to supply high-frequency power from the above to turn the gas into plasma, but the gas may be turned into plasma by the high-frequency power in order to enhance reactivity. In this case, 450 kHz to 6
0 MHz, preferably 450 kHz to 13.56 MHz
At a frequency of 200 to 1000 W, preferably 200 to 1000 W
Supply high frequency power of 500W. When plasma is formed in this manner, the reactivity of the gas is high, so that the wafer W
Temperature is 300-700 ° C, preferably 400-600
It is about ℃.

After the film formation process, NH ₃ gas and TiC are added.
The l ₄ gas is stopped, _{N 2} from the _{N 2} gas supply source 53, 55
Gas is preferably 1 to 10 L as a purge gas
/ Min to purge the chamber 31 (STEP 13), and then N ₂ gas and NH ₃
A gas is flown to perform a nitride treatment on the surface of the TiN thin film formed on the wafer W (STEP 14). N _{2 at} this time
The gas may be supplied from either the first and second N ₂ gas supply sources 53 and 55, or may be supplied from both of them. In addition, this nitride process is performed as needed.

After a lapse of a predetermined time, the N ₂ gas and the NH ₃ gas are gradually stopped (STEP 15), and the film forming process is terminated when the supply of these gases is completely stopped (STEP 16).

After that, the gate valve 73 is opened and the blade 14a or 14b of the wafer transfer device 12 is inserted into the chamber 31, and the wafer W is moved to the blade 14a or 1.
4b, and carry it out to the wafer transfer chamber 5 (STEP 1
7).

After a predetermined number of films, for example, 25 films have been formed in this way, the temperature in the chamber 31 is lowered to about 300 ° C., and ClF ₃ gas is supplied from the ClF ₃ gas supply source 51 into the chamber 31 for cleaning. Processing is performed, and in preparation for the film forming process of the next lot of wafers,
Pre-heating, pre-flow, pre-coating, treatment for oxidizing metal halide and the like are carried out in the same manner as above.

In such a film forming process, TiCl
_FourAnd NH_ThreeTo react with the inner wall of the chamber 31 and
A TiN plug is used for the chamber inner member such as the shower head 40.
Recoating is performed, and then TiCl_FourAnd NH_Three
To react with and form a TiN film on the wafer W.
HCl as a by-product of this TiN production reaction
-Created within 31. In the conventional process, this HCl
And A constituting the chamber 31 and the shower head 40
Al, Cu, Fe, etc. contained in l-materials and stainless steel materials
AlCl reacts with metallic elements_Three, CuCl_Two, FeC
l_Two, FeCl _ThreeMetal chlorides such as
The quality is vaporized during the film formation process of the wafer W and spreads inside the chamber.
A lot of metal contamination occurs due to scattering
Was. Similarly, during cleaning, metal fluoride is used.
Things are generated and cause metal contamination.
It is also possible that On the other hand, in the present embodiment,
After precoating, the wafer W is loaded into the chamber 31.
Before the O inside the chamber 31_TwoSupplying gas to the above metal
A metal that oxidizes halides and is more stable and less likely to evaporate
Since it is an oxide, it is not suitable for the wafer W film formation process.
Of metal halides that vaporize and diffuse in chamber 31
Volume, which reduces the amount of metal contamination
Can be reduced.

When such a metal halide oxidation treatment is performed during precoating or film formation, TiCl, which is a film forming gas, is used.
₄ is oxidized to produce TiO ₂ , and HCl or HF is produced from ClF ₃ if it is carried out during cleaning. Therefore, in the present embodiment, a process of oxidizing the metal halide is performed in a state where the wafer W does not exist in the chamber 31, avoiding precoating, film formation, and cleaning. As a result, the metal contamination can be reduced without causing the inconvenience and without adversely affecting the wafer W. It should be noted that when such a process is repeated, metal oxides accumulate on the inner wall of the chamber 31 or the like, which can be removed during periodic cleaning or the like.

Next, in order to confirm the effects of the present invention,
The result of the experiment is shown. Here, the backup of STEP1 above
The heating step is performed with the first and second N_TwoGas supply source 53 and
55 to N_TwoWhile flowing gas by 0.5 L / min
The temperature inside the chamber 31 is set to 680 ° C.
For 3600 seconds, then the first N _Two
Gas supply source 53, NH_ThreeGas source 54 and TiCl
_FourGas supply source 52 to N_TwoGas, NH_ThreeGas and Ti
Cl_FourGas 0.05L / min, 0.4L / min
Introduced at a flow rate of min and 0.045 L / min,
The pressure in the chamber is 40 Pa and the preflow of STEP2
For 10 seconds, then use the same gas flow rate and pressure
Pre-coating with STEP3 for 1080 seconds while maintaining
I went. After that, the STEP4 purge step is performed for 10 seconds.
After doing the first and second N_TwoGas source 53 and
55 to N_TwoFlow gas at 0.05 L / min, NH
_ThreeNH from gas supply source 54_ThreeFlow gas at 1 L / min,
18 steps of nitriding treatment of STEP5 at pressure 466Pa
Perform the purge step of STEP 6 for 0 seconds and then 10 seconds.
After that, the oxidation treatment step of STEP 7 was performed. STE
The oxidation treatment step of P7 includes the first and second N_TwoGas supply
Source 53 and 55 to N_Two0.45 L / min without gas
One, O_TwoGas source 56 to O_TwoGas 0.05L / m
Flow in, pressure is 133 Pa, susceptor temperature is 680 ° C
For 120 seconds.

After that, the vacuum evacuation in STEP 8 is totaled 30 times.
After 9 seconds, STEP 9 wafer loading and STEP
The preheating of the wafer 10 and the preflow of STEP 11 were performed for 10 seconds at the same gas flow rate as in the above precoating, and then the film forming step of STEP 12 was performed. The film forming process was continuously performed for 25 sheets for 35 seconds per sheet. In order to understand the metal contamination of each wafer at this time, the number of Al and Cu atoms on the wafer is measured by IC.
Each wafer was grasped by the P mass spectrometer. The result is shown in FIG. On the other hand, for comparison, A of each wafer when 25 continuous films were formed by the same conventional standard method except that the oxidation treatment step of STEP 7 was not performed
The numbers of atoms of l and Cu are shown in FIG. As shown in FIGS. 5 and 6, it was confirmed that the number of metal contamination tends to decrease by interposing the oxidation treatment step.

The present invention can be variously modified without being limited to the above embodiment. For example, in the above-described embodiment, O ₂ gas was used in the oxidation treatment step, but the present invention is not limited to this, and any gas containing oxygen capable of oxidizing a metal halide, such as NO _x , N ₂ O, and O ₃ , can be used. Applicable. Further, in the above-described embodiment, the metal halide oxidation treatment step is performed after pre-coating and before wafer loading. However, the present invention is not limited to this, and may be performed when the wafer is not in the chamber. It doesn't matter. Furthermore, in the above embodiment, the case where the TiN film is formed has been described.
The present invention is not limited to this, and can be applied to film formation processing of other materials, and is particularly suitable for Ti and W film formation that generally uses a halogenated gas, like TiN film formation. Further, although the case where the gas containing Cl as the halogen element is used has been described in the above embodiment, it is also effective for the treatment using the gas containing other halogen element such as F. Further, although the CVD film forming process is described in the above embodiment, the present invention can be applied to other gas processes such as etching process and ashing process. Furthermore, the substrate to be processed is not limited to a semiconductor wafer, and may be another substrate such as a liquid crystal display (LCD) substrate.
Other layers may be formed on the substrate.

[0038]

As described above, according to the present invention,
In the state where the substrate to be processed does not exist in the chamber, a gas containing oxygen is introduced into the chamber to oxidize the metal halide existing in the chamber into a metal oxide, and thus the substrate to be processed after that. It is possible to reduce the amount of metal halides that are easily vaporized in the chamber when performing gas treatment such as film formation, and to reduce particles in the chamber and thus metal contamination on the substrate to be treated. You can In particular, in the case of the film forming process, it is possible to obtain a great effect that the deterioration of the transistor characteristics can be suppressed by reducing the metal contamination in this way.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a multi-chamber type film forming system equipped with a TiN film forming apparatus for carrying out the method of the present invention.

FIG. 2 is a sectional view showing a contact hole portion of a semiconductor device using a TiN film as a barrier layer.

FIG. 3 is a CV which is an embodiment of the gas treatment method of the present invention.
Sectional drawing which shows the TiN film-forming apparatus which implements D film-forming method.

FIG. 4 is a CV which is an embodiment of the gas treatment method of the present invention.
6 is a flowchart for explaining the steps of the D film forming method.

FIG. 5 is a graph showing the numbers of Al and Cu atoms on each wafer when 25 TiN films are continuously formed according to the method of the present invention.

FIG. 6 is a graph showing the numbers of Al and Cu atoms on each wafer when 25 TiN films are continuously formed according to the conventional method.

[Explanation of symbols]

3, 4 ... TiN film forming apparatus 31 ... Chamber 32 ... Susceptor 35 ... Heater 40 ... Shower head 50 ... Gas supply mechanism 56 ... O ₂ gas supply source W ... Semiconductor wafer

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Claims (6)

[Claims] 1. A step of supplying a gas containing a halogen element into a chamber containing a substrate to be processed to perform gas treatment on the substrate, and a substrate not being present in the chamber, Introducing a gas containing oxygen into the chamber,
And a step of oxidizing a metal halide present in the chamber. 2. The gas treatment is performed while heating the substrate to be treated in the step of performing the gas treatment.
The gas treatment method described in. 3. The gas processing method according to claim 1, wherein, in the step of performing the gas processing, the processing gas is turned into plasma to process the substrate to be processed. 4. The gas treatment method according to claim 1, wherein the gas treatment is a film forming treatment. 5. The film forming process is performed using Ti, TiN or W.
The gas treatment method according to claim 4, wherein the film is formed. 6. A step of supplying a gas containing a halogen element in a chamber for accommodating a substrate to be processed in a state where the substrate to be processed is not present, and precoating a predetermined film on the surfaces of the chamber inner wall and the chamber inner member. And a step of introducing a gas containing oxygen into the chamber to oxidize a metal halide present in the chamber, and then carrying in a substrate to be processed into the chamber and containing a gas containing the halogen element. And a step of forming a thin film on the substrate to be processed, the gas processing method.