JP3058152B2 - Film forming apparatus and film forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus for forming a metal oxide film suitable for an insulating film such as tantalum oxide and the like.
And a film forming method .

[0002]

2. Description of the Related Art In general, in order to manufacture a semiconductor device, a film forming process and a pattern etching process are repeatedly performed on a semiconductor wafer to manufacture a desired device. With the increase in integration, the specifications have become stricter year by year.For example, even thinner oxide films such as capacitor insulating films and gate insulating films in devices have been required to be further thinned. At the same time, higher insulating properties are required.

As these insulating films, a silicon oxide film, a silicon nitride film or the like can be used.
Recently, a metal oxide film such as tantalum oxide (Ta ₂ O ₅ ) has tended to be used as a material having better insulating properties. This metal oxide film can exhibit highly reliable insulation even if it is thin. In order to form this metal oxide film, for example, a case of forming tantalum oxide will be described as an example. As disclosed in the above publication, a metal alkoxide of tantalum (Ta (OC (OC
₂ H _{5) 5)} used, which maintains the semiconductor wafer by supplying while bubbling with helium gas or the like for example the process temperature of about 400 ° C., under a vacuum atmosphere CVD (Ch
A tantalum oxide film (Ta ₂ O ₅ ) is laminated by an electrical vapor deposition.

FIG. 9 is a schematic diagram showing a conventional film forming apparatus for forming the above-described tantalum oxide film. FIG. 10 is a plan view showing a gas injection surface of a shower head in the film forming apparatus shown in FIG. FIG. The film forming apparatus 2 has a cylindrical processing container 4 that can be evacuated, and a mounting table 6 on which a semiconductor wafer W is mounted is provided on the upper surface thereof, and a mounting table 6 is provided above the mounting table 6. A shower head 8 is provided so as to face the mounting table 6. In the shower head section 8, a metal alkoxide, which is, for example, a liquid organic metal material, such as Ta (OC ₂ H), is used as the metal-containing source gas.
₅ ) A gas vaporized by bubbling ₅ with He gas or the like is introduced, and an oxidizing gas, for example, O ₂ gas is also introduced. Each of these gases is individually injected into the processing vessel 4 from the source gas injection holes 12A and the oxidizing gas injection holes 12B provided on the gas injection surface 10 on the lower surface of the shower head section 8, and the processing space S And mixed. The mixed gas reacts on the surface of the wafer W to form Ta on the surface of the wafer W as a metal oxide film.
_{A 2} O ₅ film will be formed.

At this time, as shown in FIG. 10, the gas ejection surface 10 of the shower head 8 has a diameter of, for example, 0.8 to 0.8.
Source gas injection hole 10A enlarged to about 1.0 mm
An oxidizing gas injection hole 10B having a diameter as small as, for example, about 0.2 to 0.3 mm is formed substantially uniformly over substantially the entire surface. The formation area of both injection holes 10A and 10B is
In order to ensure the uniformity of the supply gas amount in the processing space S, the supply gas amount is set to be equal to or slightly larger than the size of the wafer area WS indicated by a chain line.
The illustrated example shown in FIG. 10 shows a case where the formation area of both the injection holes 10A and 10B is slightly larger than the wafer area WS.

[0006]

By the way, as an insulating film used for a semiconductor device, a thin film having excellent withstand voltage characteristics is required.
In the Ta ₂ O ₅ film formed by the method described above, the organic substance C
It is inevitable that reaction by-products such as H ₃ CHO, etc., are mixed in, although they are very small. Therefore, there is a problem that the withstand voltage characteristics and the like are deteriorated by the influence of the mixed reaction by-products. . The present invention has been devised in view of the above problems and effectively solving them. An object of the present invention is to increase the injection speed by narrowing the injection region of the metal-containing source gas, thereby suppressing the amount of reaction by-products contained in the film and improving the withstand voltage characteristics and the like. It is to provide a film forming apparatus.

[0007]

According to a first aspect of the present invention, a metal-containing source gas and an oxidizing gas are supplied to a shower head provided on a ceiling in a processing vessel, and the two gases are supplied to the shower head. The raw material gas injection holes and the oxidizing gas injection holes provided on the gas injection surface on the lower surface of the head portion are separately introduced into the processing container and placed on the mounting table in the processing container. In a film forming apparatus for forming a metal-containing film on the surface of the processed object, the formation region of the source gas injection holes is set to be smaller than the area corresponding to the upper surface of the object on the mounting table. The injection speed of the metal-containing source gas from the source gas injection holes is increased , and the oxidizing gas is increased.
The formation region of the injection hole corresponds to the upper surface of the object to be processed.
The area should be approximately the same as or larger than the area
It is set to.

As a result, the concentration of the reaction by-product immediately above the surface of the object to be processed is reduced, and the concentration of the metal-containing raw material gas is increased in this portion, so that the amount of the reaction by-product taken into the film is reduced. Can be greatly suppressed. In this case, in the shower head, the metal-containing source gas and the oxidizing gas flow in a partitioned state.

The diameter of the source gas injection hole forming region is set in a range of 5/8 to 7/8 of the diameter of the upper surface of the object to be processed.

If the ratio of the two diameters is less than 5/8, the difference in the concentration of the source gas on the surface of the object to be processed becomes too large, and the in-plane uniformity of the film thickness deteriorates. If the ratio is larger than 7/8, the incorporation of reaction by-products deteriorates the withstand voltage characteristics as in the conventional apparatus. In such a film forming process, for example, the metal-containing source gas is a metal alkoxide (Ta (OC ₂ H ₅ )).
₅ ), wherein the metal-containing film is a Ta ₂ O ₅ film, and the oxidizing gas is an O ₂ gas.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a film forming apparatus and a film forming apparatus according to the present invention will be described.
An embodiment of a film forming method will be described in detail with reference to the accompanying drawings.
FIG. 1 is a configuration diagram showing a film forming apparatus according to the present invention, and FIG.
It is a top view which shows the gas injection surface of the shower head part shown inside. Here, a metal alkoxide, for example, Ta (OC ₂ H ₅ ) ₅ is used as the metal-containing source gas, O ₂ gas is used as the oxidizing gas, and Ta ₂ is used as the metal-containing film.
The case where an O ₅ film is formed will be described as an example. As shown, the film forming apparatus 14 has a processing container 16 formed of, for example, aluminum into a cylindrical shape. A feed line insertion hole 20 is provided at the center of the bottom 18 of the processing container 16.
Is formed and an exhaust port 28 connected to a vacuum exhaust system 26 provided with a vacuum pump, for example, a turbo molecular pump 22 and a dry pump 24, is provided in the peripheral portion, so that the inside of the container can be evacuated. And A plurality of, for example, about four, exhaust ports 28 are provided on the same circumference at equal intervals on the container bottom portion 18, and the exhaust ports 28 are commonly connected by a vacuum exhaust system 26.

A non-conductive material,
For example, a disc-shaped mounting table 30 made of alumina is provided, and a hollow cylindrical leg 32 extending downward is integrally formed at the center of the lower surface of the mounting table 30, and a lower end of the leg 32 is formed as described above. Around the power supply line insertion hole 20 in the container bottom 18, a sealing member 34 such as an O-ring is interposed and airtightly attached and fixed using a bolt 36 or the like. Therefore, this hollow leg 3
The inside of 2 is opened to the outside, and is in an airtight state with respect to the inside of the processing container 16. The mounting table 30 includes, for example, Si
Carbon resistance heating element 3 coated with C
The semiconductor wafer W as an object to be processed placed on the upper surface side can be heated to a desired temperature. The upper portion of the mounting table 30 is configured as a thin ceramic electrostatic chuck 42 in which a chuck electrode 40 made of a conductive plate such as copper is embedded, and the Coulomb force generated by the electrostatic chuck 42 The wafer W is held by suction on the upper surface. A backside gas such as He gas may be flowed over the surface of the electrostatic chuck 42 to improve the thermal conductivity to the wafer or prevent film formation on the back surface of the wafer. Further, a mechanical clamp may be used in place of the electrostatic chuck 42.

An insulated power supply lead wire 44 is connected to the resistance heating element 38. The power supply lead wire 44 is connected to the inside of the cylindrical leg 32 and the power supply line insertion hole without being exposed to the inside of the processing container 16. It is pulled out through 20 and connected to a power supply 48 via an open / close switch 46. Further, an insulated power supply lead wire 50 is connected to the chuck electrode 40 of the electrostatic chuck 42, and the lead wire 50 is also not exposed to the inside of the processing container 16, but inside the cylindrical leg 32 and the power supply line. The switch 52 is pulled out through the insertion hole 20 and is opened and closed.
Is connected to the high-voltage DC power supply 54 via the. The wafer may be heated by using a heating lamp such as a halogen lamp instead of the resistance heating element 38.

A plurality of lifter holes 56 are provided at predetermined positions in the peripheral portion of the mounting table 30 so as to penetrate vertically, and wafer lifter pins 58 are vertically movable in the lifter holes 56. When the wafer W is loaded and unloaded, a lift mechanism (not shown) raises and lowers the lifter pins 58 to lift and lower the wafer W. Generally, three such wafer lifter pins 58 are provided corresponding to the peripheral portion of the wafer. Further, a ceiling plate 62 integrally provided with a shower head portion 60 which is a feature of the present invention is hermetically attached to a ceiling portion of the processing container 16 via a sealing member 64 such as an O-ring. The shower head unit 60 is provided so as to face substantially the entire upper surface of the mounting table 30 or to face it so as to cover the entire surface of the mounting table 30 more widely, and forms a processing space S with the mounting table 30. The shower head section 60 introduces a metal-containing source gas and an oxidizing gas for film formation into the processing chamber 16 in a shower shape.
A large number of source gas injection holes 68 and oxidizing gas injection holes 70 for individually injecting each gas are formed on the gas injection surface 66 on the lower surface of the nozzle 0.

The inside of the shower head section 60 has a head space 72 for raw material gas and a head space 74 for oxidizing gas.
A gas supply port 78 extending from a bubbling device (not shown) is connected to a gas introduction port 76 which is divided into two sections and communicates with a source gas head space 72, for example, a vaporized Ta bubbled by He gas. (OC
₂ H ₅ ) ₅ has been introduced. Also, the gas supply passage 80 is connected to an oxidizing gas introduction port 79 which is communicated with the oxidizing gas head space 74 so as to introduce O ₂ gas. The source gas head space 72 communicates with each of the source gas injection holes 68, and the oxidizing gas head space 74 communicates with each of the oxidizing gas injection holes 70. 68, 70
Were mixed with the ejected material gas and O ₂ gas and the processing space S from, and supplies the so-called post-mix state. A tape heater 82 for preventing reliquefaction of the source gas flowing through the source supply passage 78 is provided.
To heat it above the liquefaction temperature.

Here, the source gas injection hole 68 and the oxidizing gas injection hole 70 are both in the same area as the area of the wafer W as shown in FIG. In the present embodiment, the oxidizing gas injection holes 70 are provided substantially uniformly in a wide area, but in this embodiment, as shown in FIG. The source gas injection holes 68 are arranged in a substantially same circular region 84W or a region having an area slightly larger than the circular region 84W, and the source gas injection holes 68 are circular regions (formation regions) 86 narrower than the region 84W. Are arranged so that they are distributed almost uniformly. In this case, the diameter of each injection hole 68, 70 is substantially the same as that of the conventional apparatus, and the diameter d1 of the raw material gas injection hole 68 is set to a large value in the range of 0.8 to 1.0 mm to prevent clogging. The diameter d2 of the oxidizing gas injection hole 70 is set small within the range of 0.2 to 0.3 mm.

In this case, the distribution density per unit area of each of the injection holes 68 and 70 is substantially the same as that of the conventional apparatus.
^{They are} about 1 / cm ² and 1 to 3 / cm ² respectively. Thus, the formation region 86 of the source gas injection hole 68 is formed.
Is set to be smaller than that of the conventional apparatus, and the injection speed of the source gas from the source gas injection holes 68 is reduced by the reduced area when the supply amount of the source gas is the same as in the conventional film forming process. Is raised.

On the side wall of the shower head 60, a cooling jacket 90 is provided for cooling the temperature of this portion to, for example, about 140 to 175 ° C. in order to prevent the decomposition of the raw material gas. A coolant of about 60 ° C., for example, hot water is allowed to flow. The distance between the shower head unit 60 and the mounting table 30 is approximately 10 to 30 m.
m. Further, on the side wall of the processing container 16, a cooling jacket 92 for flowing, for example, a coolant for cooling the wall surface is provided. Hot water of, for example, about 60 ° C. is flowed as a cooling medium, and the raw material gas is not liquefied on the side surface. , And is maintained at a temperature at which thermal decomposition does not occur, for example, within a range of 140 to 170 ° C. In addition, this container 1
6, a wafer loading / unloading port 94 is provided in a part of the side wall.
The gate valve 98 is provided here for communicating with and shutting off from a load lock chamber 96 which can be evacuated. Although not shown, it is a matter of course that a means for supplying N ₂ gas for purging is provided.

Next, a film forming process performed using the film forming apparatus configured as described above will be described. First, an unprocessed semiconductor wafer W is loaded from the load lock chamber 96 through the wafer loading / unloading port 94 into the processing chamber 16 maintained in a vacuum state, and the unprocessed semiconductor wafer W is mounted on the mounting table 30 to be electrostatically charged. It is held by suction by the Coulomb force of the chuck 42. The raw material gas and the oxidizing gas are supplied from the shower head unit 60 while maintaining the wafer W at a predetermined process temperature by the resistance heating element 38 and evacuating the processing chamber 16 to a predetermined process pressure. To start film formation.
As the source gas, a liquid organic compound of Ta (OC ₂ H
₅ ) ₅ is supplied in a vaporized state by bubbling with He gas, and the supply amount is very small, for example, about several mg / min, depending on the film formation rate. The source gas that has reached the shower head section 60 once flows into the source gas head space 72, and is supplied to the processing space S from the source gas injection hole 68 having a large diameter provided on the gas injection surface 66.

On the other hand, the O flowing through the gas introduction passage 80
_{The two} gases reach the oxidizing gas head space 74 of the shower head section 60, and are supplied to the processing space S from the oxidizing gas injection hole 70 having a small diameter provided on the gas injection surface 66. The raw material gas and the O ₂ gas ejected to the processing space S in this manner are mixed and reacted in the processing space S, and for example, a tantalum oxide film (Ta ₂ O ₅ ) is deposited on the surface of the wafer by CVD. At the same time as filming, CH ₃ C
Reaction by-products such as HO will be produced. For example, when processing an 8-inch wafer, the film forming process pressure is set to about 02 to 0.3 Torr, and the process temperature is set to a range of 250 to 450 ° C., for example, 400 ° C. The supply amount of the raw material gas is 15 mg / min, H
The supply amount of the e gas is about 300 sccm, and the supply amount of the O ₂ gas is about 1000 sccm.

In this case, in this embodiment, by setting the area of the formation region 86 of the source gas injection holes 68 to be smaller than that of the conventional apparatus, the supply amount of the source gas is the same as that of the conventional film forming process. In this case, the injection speed of the source gas from the source gas injection holes 68 is increased by the reduced area. As a result, the source gas can reach the wafer surface without being thermally decomposed on the way to increase the concentration of the source gas immediately above the surface of the wafer W, and reduce the gas concentration of the reaction by-product in this portion. It is possible to do. As described above, when the concentration of the reaction by-product such as CH ₃ CHO directly above the wafer surface is reduced, the probability of the reaction by-product being taken in during the film formation is reduced, and the withstand voltage characteristics of the film can be improved.

In this case, the ratio D1 / D2 of the diameter D1 of the formation region 86 of the source gas injection holes 68 to the region D2 having the same area as the wafer W is set to be in the range of 5/8 to 7/8. . If the source gas injection holes 68 are formed in a narrower area where the ratio is smaller than 5/8, the source gas injection speed further increases, and the source gas concentration in the central portion of the processing space S becomes too high, and the In this case, the thickness of the metal oxide film becomes too large, and the uniformity of the thickness in the wafer surface is deteriorated.
Conversely, when the ratio is larger than 7/8 and approaches the configuration of the conventional device, the dielectric breakdown voltage characteristics of the metal oxide film deteriorate as described in the section of the problem to be solved by the invention. If you simply increase the injection speed of the source gas,
The supply pressure of the raw material gas may be increased, but in this case, the supply amount of the raw material gas is greatly increased, and accordingly, another gas such as He gas or O 2 for bubbling is added.
₂ The supply of gas must also increase. In particular, when the wafer size is 12 inches, the amount of increase of all the gases is considerably large, which is not practical.

Here, the evaluation of tantalum oxide formed as an insulating film was performed using the apparatus of the present invention and the conventional apparatus, and the evaluation results are shown in FIG. The structure of the shower head section 60 here is set to 6 inches in diameter D2 and 4.5 inches in diameter D1 in FIG. 2 in order to process a 6-inch wafer W. In FIG. 3, the conventional device indicated by a square mark has both gas injection holes 68 and
In the apparatus of the present invention, which is provided uniformly with a circle 70, the source gas injection holes 68 are provided in the area of the diameter D1, and the distribution of the oxidizing gas injection holes 70 is the same as that of the conventional apparatus. The process conditions at this time are as follows: the wafer temperature is 450 ° C., and the pressure is 0.
225 Torr, source gas (Pet) flow rate is 15 mg
/ Min, the flow rate of O ₂ is 1000 sccm, and the flow rate of He is 250 sccm. As is apparent from this graph, regardless of the film thickness, the insulating film of the present invention shows a higher dielectric strength than the insulating film of the conventional device,
It turns out that the characteristics are good. In particular, it turns out that the insulating film of the device of the present invention shows high insulating characteristics even when the effective film thickness is as thin as about 2.3 nm.

Next, the concentration distributions of the raw material gas and the reaction by-product below the shower head of the conventional apparatus and the apparatus of the present invention were evaluated by simulation, and the evaluation results are shown. FIG. 4 shows the source gas (Ta ₂ (OC ₂ H ₅ ) ₅ : P
FIG. 5 shows the concentration distribution of the reaction by-product (CH ₃
3 shows the concentration distribution of (CHO). 4A and 4B, (A) shows a diameter D1 (FIG. 2) for an 8-inch wafer.
3) shows the case of the apparatus of the present invention in which the raw material gas injection holes 68 are provided up to the area of 6 inches, and FIG.
This shows a case of a conventional apparatus in which source gas injection holes are provided up to the inch area. First, as is clear from FIG. 4, the concentration of the source gas gradually decreases from the shower head 60 toward the surface of the wafer W. And
In the case of the apparatus of the present invention shown in FIG. 4A, the concentration of the source gas immediately above the wafer W is 1.9 to 2.0 × 10 ⁻⁶ m.
ol / m ³ , whereas in the case of the conventional apparatus shown in FIG. 4B, 1.7 to 1.8 × 10 ⁻⁶ mol / m ^3.
And the concentration is much higher in the case of the apparatus of the present invention. That is, in the case of the apparatus of the present invention, it is clear that among the injected source gases, many source gases reach the wafer surface without being decomposed on the way.

On the other hand, as apparent from FIG. 5, the concentration of the reaction by-product gradually increases from the shower head portion 60 toward the surface of the wafer W. And in the case of the device of the present invention shown in FIG.
The concentration of the reaction by-product immediately above the wafer W is 50 to 6
In contrast to about 0 × 10 ⁻⁶ mol / m ³ , FIG.
75-85 × 10 ⁻⁶ m in the case of the conventional device shown in FIG.
ol / m ³ , which is much lower in the case of the apparatus of the present invention. That is, it is found that the efficiency of removing the reaction by-products is higher in the case of the apparatus of the present invention because the injection speed of the raw material gas is higher.

Next, similarly to the case shown in FIGS. 4 and 5, when a film forming process is performed on an 8-inch wafer, the diameter D1 ( Simulations were performed when various changes were made to FIG. 2), and the evaluation results at that time will be described. The concentration was measured by measuring the source gas and C directly above the wafer surface.
H ₃ CHO (reaction by-product)
Further, the film formation rate was also measured. The diameter D1 of the region where the oxidizing gas injection holes are formed is 8 inches as in the case shown in FIGS. First, FIG. 6 is a graph showing a simulation result of a source gas concentration on a wafer surface. In the figure, curves A to D show the source gas concentrations, and curves E to H show the O ₂ gas concentrations. Further, among the numerical values described corresponding to each curve, the numerical value on the left side indicates the diameter (inch) of the formation region D1 of the source gas injection holes, and the numerical value on the right side indicates the wafer size or the formation region of the oxidizing gas injection holes. D
2 indicates the diameter (inches). Therefore, for example, 8-8 indicates a shower head portion of the conventional apparatus, and 6-8 indicates a typical example of the apparatus of the present invention. This display method is the same in FIG. 7 and FIG.

As shown in FIG. 6, the concentration distribution of the source gas (curves A to D) sharply decreases within a range of 80 mm to 100 mm from the center of the wafer. Also, between the center of the wafer and 80 mm,
Curve D (conventional device) is not good due to low density. On the other hand, in the order of the curves C, B, and A, that is, as the diameter D1 becomes smaller, the raw material gas concentration immediately above the wafer surface becomes higher, showing a good result. FIG. 7 is a graph showing a simulation result of a reaction by-product (CH ₃ CHO) concentration on a wafer surface. In the curve E (8-8) showing the conventional apparatus, the concentration of the reaction by-products as a whole is as high as 7.0 × 10 ⁻⁷ mol / m ³ or more, which is not a very good result. On the other hand, in the curves F to H according to the present invention, the concentration is 6. from the center to the center of the wafer.
The concentration is reduced to 0 × 10 ⁻⁷ mol / m ³ or less, and the concentration of the reaction by-product is gradually reduced in this order, and the concentration is gradually increased in the peripheral portion of the wafer. Therefore, as the diameter D1 (see FIG. 2) decreases, the injection speed of the source gas increases, and it is found that the effect of eliminating the reaction by-products in the central portion and the peripheral portion of the wafer increases.

FIG. 8 is a graph showing a simulation result of a deposition rate of a tantalum oxide film in a wafer surface. As is clear from this graph, a curve L indicating the conventional device is shown.
In the case of (8-8), the central portion of the wafer is 1.10 nm.
/ Min, and 0.95 nm / min in the peripheral portion of the wafer.
The curves K to I showing the apparatus of the present invention are curves in which the source gas concentration increases in the central portion of the wafer as described above, and thus the film forming rate in the central portion of the wafer increases in the above order, and In the case of I, the film forming rate at the center becomes 1.20 nm / min. However, in this case, the film formation rate at the periphery of the wafer is 0.95 nm.
/ Min is 0.25 nm / min, which is within the allowable range without significantly deteriorating the in-plane uniformity of the film formation. Further, if the difference between the film forming rates at the central portion and the peripheral portion of the wafer is further increased, the in-plane uniformity of the film is undesirably deteriorated. Therefore, from the above results, it is necessary to set the ratio D1 / D2 between the diameters D1 and D2 in FIG. 2 within a range of 5/8 to 7/8, and preferably set to about 6/8. Turns out to be good. In the above simulation, an 8-inch wafer has been described as an example.
The application range of 1 / D2 is of course applicable to processing wafers of 12-inch size, 6-inch size or other sizes regardless of the wafer size.

In the above embodiment, O is used as the oxidizing gas.
₂ , but not limited thereto, O ₃ , N ₂ O, N
O, vaporized alcohol, or the like may be used. Further, as the metal-containing film, a metal nitride film such as TiN or WN or a metal film such as Pt, Ru, Ir, or Ti can be used. In this case, the complex compound Tris (pentanedio) is used as the metal-containing source gas.
_{nato) iridium: C 5 H 7} O 2) 3 Ir, T
etakis (diethylamido) tita
Nium: [(CH ₃ CH ₂ ) ₂ N] ₄ Ti, Bis
(Cyclopentadienyl) rutheni
_{um: (C 5 H 5)} 2 Ru, Methylcyclop
entadienyl (trimethyl) plat
inum: (CH ₃ C ₃ H ₄ ) (CH ₃ ) ₃ Pt or the like can be used.

[0030]

As described above, according to the film forming apparatus and the film forming method of the present invention, the following excellent functions and effects can be exhibited. The region where the source gas injection holes are formed is set smaller than the area corresponding to the upper surface of the object to be processed, so that the injection speed of the source gas is increased correspondingly, and the oxidizing gas is further increased.
The area where the injection holes are formed has an area corresponding to the upper surface of the workpiece.
The area should be approximately the same as or larger than this.
Since the oxidizing gas is supplied constantly, the concentration of the raw material gas directly above the surface of the object can be increased and the concentration of the reaction by-product can be reduced. Therefore, the amount of reaction by-products contained during the film formation can be suppressed, so that the withstand voltage characteristics can be improved without deteriorating the in-plane uniformity of the film thickness.
In particular, by setting the diameter of the region where the source gas injection holes are formed to be within the range of ／ to ／ of the diameter of the upper surface of the object to be processed, the above-mentioned dielectric strength characteristics can be further enhanced.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a gas ejection surface of a shower head shown in FIG.

FIG. 3 is a diagram showing evaluation results of tantalum oxide formed as an insulating film using the apparatus of the present invention and a conventional apparatus.

FIG. 4 Source gas (Ta ₂ (OC ₂ H ₅ ) ₅ : Pet)
FIG. 5 is a diagram showing a density distribution of the present invention.

FIG. 5 is a diagram showing a concentration distribution of a reaction by-product (CH ₃ CHO).

FIG. 6 is a diagram showing a concentration distribution of a source gas.

FIG. 7 shows a reaction by-product (CH ₃ CH) on a wafer surface.
It is a graph which shows the simulation result of O) density | concentration.

FIG. 8 is a graph showing a simulation result of a deposition rate of a tantalum oxide film in a wafer surface.

FIG. 9 is a schematic configuration diagram showing a conventional film forming apparatus when forming a tantalum oxide film.

10 is a plan view showing a gas injection surface of a shower head in the film forming apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 14 Film-forming apparatus 16 Processing container 30 Mounting table 60 Shower head part 66 Gas injection surface 68 Source gas injection hole 70 Oxidizing gas injection hole 72 Head space for source gas 74 Head space for oxidizing gas 84W The area of the same area as a semiconductor wafer 86 area W semiconductor wafer (object to be processed)

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 H01L 21/205 H01L 21/31-21/318 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A metal-containing source gas and an oxidizing gas are supplied to a shower head provided on a ceiling in a processing vessel, and the two gases are supplied on a gas injection surface on a lower surface of the shower head. In a film forming apparatus for introducing a metal-containing film on a surface of a processing target placed on a mounting table in the processing container by separately introducing the processing hole from the injection hole and the oxidizing gas injection hole into the processing container. The area for forming the source gas injection holes is set smaller than the area corresponding to the upper surface of the object to be processed on the mounting table, so as to increase the injection speed of the metal-containing source gas from the source gas injection holes. Before and
The formation region of the oxidizing gas injection hole is located on the upper surface of the object to be processed.
Area approximately equal to or larger than the area corresponding to
A film forming apparatus characterized by being set so as to be as follows. Wherein the diameter of the forming regions of the source gas injection holes, according to claim 1 Symbol, wherein the set in the range of 5 / 8-7 / 8 of the diameter of the upper surface of the object Film forming equipment. 3. The metal-containing source gas is a metal alkoxide (Ta (OC ₂ H ₅ ) ₅ ), the metal-containing film is a Ta ₂ O ₅ film, and the oxidizing gas is an O ₂ gas. the deposition apparatus according to claim 1 or 2, characterized in. 4. A metal-containing source gas and an oxidizing gas are supplied to a shower head provided on a ceiling in a processing vessel, and the two gases are supplied on a gas injection surface on a lower surface of the shower head. In a film forming method for forming a metal-containing film on a surface of a processing object mounted on a mounting table in the processing container by separately introducing the processing hole from the injection hole and the oxidizing gas injection hole into the processing container, the by injecting the raw material gas injection holes or found before <br/> Symbol metal-containing raw material gas toward the inner narrow area than the area of the upper surface of the workpiece as well as to enhance the injection speed, the Approximately the area of the top surface of the object
Or the oxidizing gas for a wider area.
A film forming method, wherein the oxidizing gas is injected from an injection hole .