JP2002275634A - Process for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a uniform film-formation based on a uniform distribution of film-forming gas concentration on a wafer which is a good film-forming atmosphere, by reducing the unevenness of the gas concentration distribution on the wafer caused by a disturbance of the film-forming atmosphere on the wafer that occurs at the introduction of a purge gas around the wafer. SOLUTION: In a process for manufacturing a semiconductor device, a film is formed on a wafer 9 by introducing a reactive gas 12, which is a film-forming gas, into a reaction chamber 10 while supplying a purge gas 11, which is a non-film-forming gas, around the wafer 9 to be treated. Here, other than the non-film-forming gas, at least one of the gases contained in the reactive gas 12 is contained as the purge gas 11 supplied around the wafer 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for forming a thin film on a substrate to be processed, doping a substrate with impurities, and oxidizing a substrate surface. Semiconductor manufacturing equipment, for example, CVD (Chemical Vapor Deposi) using a multi-component mixed gas containing a source gas.
The present invention relates to a method for manufacturing a semiconductor device in an apparatus.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show MO-CVD (Metal Orga).
nic Chemical Vapor Deposition)
FIG. 3 is a cross-sectional view showing the configuration of the apparatus, in which FIG. 3 shows a case of a wafer film formation position and FIG. 4 shows a case of a wafer transfer position.

[0003] Reference numeral 10 denotes a reaction chamber (that is, a processing chamber), 9 denotes a substrate to be processed, ie, a wafer, and 1 denotes a reaction in which a reaction gas such as a deposition gas is uniformly dispersed and supplied into the reaction chamber 10. Shower head which is a gas supply means, 2 is wafer 9
Is a plate heater which is a heating element for heating the wafer 9, 4 is a side heater which is a heating element for heating the wall surface of the reaction chamber 10, and 5 is a side heater which covers the reaction gas to prevent reaction gas. A side cover, 6 is a cover plate for covering the susceptor 2 for preventing reaction gas deposition, 7 is a push-up pin for the wafer 9, 8 is an exhaust port, 13 is a stepped portion, and 100 is a heater unit.

[0004] Hereinafter, an assembly composed of 2 to 7 will be generically referred to as a heater unit 100.

The heater unit 100 has a vertical drive mechanism (not shown) that reciprocates between a wafer deposition position shown in FIG. 3 and a wafer transfer position shown in FIG. 4 in the reaction chamber 10.

A wafer film forming process for forming a thin film on the wafer 9 is as follows.

First, the reaction chamber 10 is moved from the shower head 1 to the reaction chamber 10.
An N ₂ gas is supplied as a purge gas thereinto, and power is supplied to the plate heater 3 and the side heater 4 to create an environment in which the inside of the reaction chamber 10 is thermally settled at a predetermined temperature at which a film is formed. The wafer 9 is transferred onto the susceptor 2 at the wafer transfer position of the heater unit 100 shown in FIG. The heater unit 100 is raised to the wafer deposition position shown in FIG. The cover plate 6 is provided with the stepped portion 1.
3 and rises to the wafer deposition position together with 2 to 7 other than the cover plate 6. Preheating is performed until the temperature of the wafer 9 reaches a predetermined temperature for forming a film. Instead of the N ₂ purge gas, a reaction gas, for example, a raw material gas + oxygen-containing gas + N ₂ carrier gas is introduced from the shower head 1 into the reaction chamber 10 to start film formation (wafer film formation processing step). Instead of the reaction gas, a shower head 1
A N ₂ purge gas is introduced thereinto to remove the gas remaining in the reaction chamber 10. The heater unit 100 is lowered to the wafer transfer position shown in FIG. The cover plate 6 is provided with the stepped portion 1.
3 and only the other 2-7 fall to the wafer transfer position. The wafer 9 is taken out of the reaction chamber 10.

[0008]

Conventionally, the problem that the film thickness distribution on the wafer is non-uniform is solved by the temperature distribution in the wafer surface, the gas flow velocity distribution on the wafer, the gas concentration distribution on the wafer, and the like. There are several possible causes.

FIG. 5 is an enlarged sectional view of an essential part of FIG. 3 showing an example of introduction of a purge gas to the periphery of the wafer, and FIG. 6 is an enlarged sectional view of an essential part of FIG. 3 showing another example of introduction of the purge gas to the periphery of the wafer. .

Reference numeral 11 denotes a purge gas, and 12 denotes a reaction gas.

Among the above-mentioned causes, regarding the gas concentration distribution on the wafer, as shown in FIG. 5 or FIG. Then, the purge gas 11 is introduced into the peripheral portion of the wafer 9.

However, with the conventional purge gas 11 composed of only N ₂ , the film formation atmosphere on the wafer 9 is disturbed, and the concentration distribution of other component gases, for example, O ₂ gas around the wafer 9 is changed. There is a problem that the temperature is reduced as compared with portions other than the peripheral portion.

For example, in the process of forming a Ru film,
The O ₂ gas contained in the reaction gas itself becomes a compound and is not taken into the formed film, but is a gas that contributes to film formation (the reaction is performed because H ₂ O and CO ₂ are generated. are doing). For this reason, it is considered necessary to make the concentration distribution uniform on the wafer 9.

An object of the present invention is to reduce non-uniformity of gas concentration distribution on a wafer due to disturbance of a film forming atmosphere on a wafer due to introduction of a purge gas to a peripheral portion of the wafer, which is a problem of the prior art, and to provide a good film forming atmosphere. An object of the present invention is to provide a method of manufacturing a semiconductor device capable of realizing uniform film formation by a uniform concentration distribution of a film-forming gas on a certain wafer.

[0015]

In order to solve the above-mentioned problems, the present invention provides a method in which a film-forming gas is introduced into a processing chamber while a non-film-forming gas is supplied to a peripheral portion of an object to be processed such as a wafer. In the method of manufacturing a semiconductor device for forming a film on the object to be processed, as a gas supplied to a peripheral portion of the object to be processed, in addition to the non-film forming gas, a gas contained in the film forming gas may be used. It is characterized in that at least one of them is contained.

In the present invention, as the purge gas supplied to the peripheral portion of the object to be processed, at least one of the gases contained in the reaction gas is contained in addition to the non-deposition gas, so that the gas to be processed is contained. Disturbance of the atmosphere of the reaction gas around the body is suppressed, a stable and uniform film formation gas atmosphere on the object to be processed is realized, and film formation with a uniform film thickness can be realized.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. The MO-CVD (Metal Organizer) used in the method of manufacturing a semiconductor device according to the present invention.
c Chemical Vapor Deposition: The configuration of the apparatus is as shown in FIG. 3 and FIG.
Since the wafer film forming process (the above-mentioned portions) is the same as that of the conventional technique, the description is omitted.

FIG. 5 is an enlarged sectional view of a main part of FIG. 3, showing an example of introduction of a purge gas to the periphery of a wafer in the present embodiment.
FIG. 6 is an enlarged cross-sectional view of a main part of FIG. 3 showing another example of introduction of a purge gas around a wafer.

Reference numeral 11 denotes a purge gas, and 12 denotes a reaction gas.

In the present embodiment, a film forming gas, ie, a reaction gas 12 is supplied to a processing chamber, ie, a reaction chamber, while a purge gas 11, which is a non-film forming gas, is supplied to a peripheral portion of, for example, a wafer 9, which is an object to be processed. In the method of manufacturing a semiconductor device in which a film is formed on the wafer 9 by being introduced into the chamber 10, as a purge gas 11 supplied to a peripheral portion of the wafer 9, a gas contained in a reactive gas 12 in addition to a non-film forming gas At least one gas is contained.

One example will be described.
2 = source gas (for example, Ru (C₂H ₅C₅H₄)₂Etc.
Ru (ruthenium) compound) + oxygen-containing gas (for example, O
₂+) Carrier that carries the source gas 12 to the reaction chamber 10
Gas (eg N₂). That is, the reaction gas (film formation
Gas) 12 is a raw material gas and a gas containing oxygen atoms and a gas.
It is a mixed gas with carrier gas. Also, the purge gas 11
Of the non-film-forming gas is an inert gas (for example, N 2₂)
The at least one gas contains an oxygen atom
Gas (eg O₂).

Purge gas 1 to be supplied to the periphery of wafer 9
1, the non-film-forming gas (for example, N ₂ ) and the at least one gas (for example, O ₂ ) of the reaction gas 12
The mixing ratio of _2), of the reaction gas 12, a gas containing oxygen atoms (e.g., _{O 2)} and the raw material gas (e.g. the _{Ru (C 2 H 5 C 5} H 4) 2 or the like of Ru (ruthenium ) Compound), that is, the mixing ratio of the carrier gas (for example, N ₂ ) and the gas containing oxygen atoms (for example, O ₂ ) is made substantially equal.

As described above, conventionally, since the reaction gas 12 is a mixed gas composed of component gases having a certain mixing ratio, a single component purge gas 11 introduced into the peripheral portion of the wafer 9 causes Is disturbed, and the concentration distribution of the reaction gas 12 on the wafer 9 becomes non-uniform.

Therefore, the concentration distribution of the reaction gas 12, especially at least one of the gases contained in the reaction gas 12 (for example, O ₂ ) can also be obtained by introducing the purge gas 11.
As a method for maintaining the concentration distribution, the non-film-forming gas (eg, N ₂ ) of the purge gas 11 contains at least one kind of gas (eg, O ₂ ), for example, each component of the reaction gas 12 excluding the source gas. A method is proposed in which a mixed gas having a mixing ratio substantially equal to the gas mixing ratio is introduced as a purge gas 11 around the wafer 9.

In order to verify the effect of this method, a numerical analysis was performed.

FIG. 1 shows a concentration distribution (kg / m ³ ) of the at least one gas (here, O ₂ ) around the wafer 9 by numerical analysis in the method of manufacturing a semiconductor device according to the embodiment of the present invention. (A), when the conventional purge gas 11 is only N ₂ (flow rate 500 sccm), (b)
Is the case where O ₂ is contained in N _{2 according} to the present invention (N ₂ : O
₂ = 0.46: 0.54 (same as the mixture ratio of N ₂ : O ₂ excluding the above-mentioned source gas of the reaction gas 12) (flow rate 500 sccm), (c) is the case of only O ₂ ( Flow rate 50
0 sccm). The analysis example of this figure is a case of the introduction example of the purge gas shown in FIG.

That is, with respect to the three kinds of gases (a) to (c) as the purge gas 11, the O ₂ gas concentration distribution around the wafer 9 was examined.

In the conventional case (a) in which the purge gas 11 is only N ₂ , the reaction gas 1 around the wafer 9 is expected, as expected.
2 was disturbed, and a phenomenon was observed in which the O ₂ concentration was lower than in other portions of the wafer 9.

[0029] _{N 2} purge gas 11 (b) is contained _{O 2,} present the mixing ratio of N 2 + _{O 2,} which is the same as the mixing ratio of _{N 2} and _{O 2} reactive gas 12 with the exception of the raw material gas In the case of the present invention, no disturbance of the atmosphere of the reaction gas 12 around the wafer 9 was observed, and the O ₂ concentration distribution on the wafer 9 was uniform over the entire area of the wafer 9.

In the case (c) where the purge gas 11 is only O ₂ , the atmosphere of the reaction gas 12 around the wafer 9 is disturbed, and in contrast to the case (a), the O ₂ concentration is changed to other parts of the wafer 9. Phenomena increased.

FIG. 2 shows the purge gas shown in FIG.
O around the wafer 9 corresponding to the introduction example₂Concentration distribution (kg
/ M³FIG. In this figure, N according to the present invention₂
To O ₂(N₂: O₂Weight ratio of 0.4
6: 0.54 (N excluding the source gas of the reaction gas 12)
₂: O₂The same as the mixing ratio)) (500 sccm flow rate)
And the purge gas 11 is N₂Only the conventional case, O
₂Illustration is omitted in the case of only.

[0032] In this diagram, the _{N 2} purge gas 11 is contained _{O 2,} the mixing ratio of N 2 + _{O 2,} was the same as the mixing ratio of _{N 2} and _{O 2} reactive gas 12 excluding raw material gas In the case of the present invention, no disturbance of the atmosphere of the reaction gas 12 around the wafer 9 was observed, and the O ₂ concentration distribution on the wafer 9 was uniform over the entire area of the wafer 9.

[0033] From the above results, as a purge gas 11 is supplied to the peripheral portion of the wafer 9, in addition to the non-film gas N _2, at least one gas of the gas contained in the reaction gas 12, for example O ₂ And the mixing ratio of the non-film-forming gas N ₂ and O ₂ is made substantially equal to the mixing ratio of N ₂ and O ₂ excluding the source gas of the reaction gas 12, so that the periphery of the wafer 9 is It was found that the disturbance of the atmosphere of the reaction gas 12 was suppressed, a stable and uniform film formation atmosphere on the wafer 9 was realized, and a film formation with a uniform film thickness was realized.

The present invention has been described in detail based on the embodiments.
However, the present invention is not limited to the above embodiment.
Instead, various changes will be made without departing from the spirit of the invention.
Of course, it is possible. For example, with non-deposition gas
The mixing ratio of at least one gas with the raw material gas
Mixture of carrier gas excluding gas and at least one gas
Ratio is not required to be almost equal to the
By including at least one gas, the present invention
The effect is obtained. In addition, the above reaction gas = raw material gas
(For example, Ru (C₂H₅C₅H₄)₂Ru (Luteni, etc.)
Um) compound) + oxygen-containing gas O₂+ N₂Carrier Ga
Is only an example and can be applied to other cases
Needless to say, it is noh. For example, at least one
Seed gas is O ₂In the case of oxygen-containing gas such as
Thermal CVD as in the Ru film formation process in the embodiment
MOCVD process, comprising:₂O₅Film formation, Z
rO₂It is also applicable to film formation and the like. In addition, oxygen-containing gas
In other cases, Si (OC ₂H₅)₄(TEOS TE
Traethoxysilane) + O₃(Ozone) → SiO₂+ Α
And SiH₄(Monosilane) + N₂O → SiO₂+ Α
It is also applicable to film formation and the like. Here, α is on the wafer
Residual gas that was not deposited on
It is a substance.

[0035]

As described above, according to the present invention,
As a purge gas supplied to the peripheral portion of the object to be processed, at least one of the gases contained in the reaction gas is contained in addition to the non-deposition gas, so that the reaction gas around the object to be processed can be removed. A disturbance in the atmosphere is suppressed, a stable and uniform film forming gas atmosphere on the object to be processed is realized, and a film having a uniform film thickness can be realized.

[Brief description of the drawings]

1A and 1B are diagrams showing an O ₂ concentration distribution around a wafer corresponding to an example of introduction of a purge gas in FIG. 5 in an embodiment of the present invention, wherein FIG. 1A shows a case where the purge gas is only N ₂ , and FIG. If the N ₂ is contained _{O 2,} (c) shows the case of only _{O 2.}

FIG. 2 shows an example in which N ₂ corresponds to O.
FIG. 4 is a diagram showing an O ₂ concentration distribution around a wafer when the compound contains ₂ ;

FIG. 3 shows an MO used in the method of manufacturing a semiconductor device according to the present invention.
-It is sectional drawing which shows the example of a structure of a CVD apparatus, and is a case of the wafer film-forming position.

FIG. 4 is the same cross-sectional view as FIG. 3, but in the case of a wafer transfer position.

FIG. 5 is a view showing an example of introduction of a purge gas around a wafer.
3 is an enlarged sectional view of a main part of FIG.

FIG. 6 is an enlarged sectional view of a main part of FIG. 3, showing another example of introduction of a purge gas around a wafer.

[Explanation of symbols]

1. Shower head, 2. Susceptor (wafer support),
3 ... plate heater, 4 ... side heater, 5 ... side cover, 6 ... cover plate, 7 ... wafer push-up pin, 8
... Exhaust port, 9 ... Wafer (object to be processed), 10 ... Reaction chamber (processing chamber), 11 ... Purge gas, 12 ... Reaction gas (film forming gas), 100 ... Heater unit.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K030 AA11 AA14 AA18 BA01 CA04 CA12 JA06 5F045 AA04 AB31 AB32 AB40 AC07 AC11 AC15 BB02 DP03 EC10 EE12 EE13

Claims (1)

[Claims] 1. A method of manufacturing a semiconductor device, wherein a film forming gas is introduced into a processing chamber while a non-film forming gas is supplied to a peripheral portion of an object to be processed, and a film is formed on the object to be processed. A method for manufacturing a semiconductor device, comprising, as a gas supplied to a peripheral portion of an object to be processed, at least one kind of gas contained in the film-forming gas, in addition to the non-film-forming gas. Method.