JPS6338430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a vapor phase growth apparatus, and more specifically,
This relates to a vapor phase growth device that can almost completely eliminate the generation of particles by using an open chamber that separates the outside world from the internal reaction area using a high-speed curtain flow of inert gas, without using a closed chamber. be.

(Prior art) A conventional vapor phase growth apparatus is, for example,
As disclosed in Publication No. 54181, a nozzle with a double tube structure is arranged facing the workpiece placed on a heating support, and a reaction gas and a carrier gas are supplied from the inner tube of the nozzle to the outer tube. An apparatus is known in which a curtain gas such as nitrogen gas is ejected from a chamber toward an object to be treated.

According to this device, it is possible to apply a reaction product by spraying in the atmosphere without requiring a reaction tube.

Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 57-187033, a reactant gas supply nozzle is used to fill the space between the support wall of the object to be treated and a quartz window that transmits ultraviolet rays irradiated from the outside. 2. Description of the Related Art A vapor phase growth apparatus is known in which a reactant gas is supplied to the surface of an object in a laminar flow, and a carrier gas is supplied in a laminar flow along a quartz window using a carrier gas supply nozzle.

(Problems to be Solved by the Invention) However, the conventional vapor phase growth apparatus described above has the following problems.

In other words, in the former device, the reaction gas and curtain gas are ejected toward the object to be treated, so a turbulent flow of the reaction gas and curtain gas occurs on the surface of the object, and the gas generated in the reaction gas is There is a problem in that phase reaction products tend to fall and adhere to the film grown on the surface of the object to be treated due to the blow-up of the reaction gas, which tends to cause so-called particles.

On the other hand, in the latter device, the gas phase reaction products generated in the reaction gas are relatively easily discharged along with the reaction gas flow, but the reaction products attached to the vessel walls such as quartz windows fall out. There is a risk that it will re-adhere to the film on the object to be treated. Particularly when heating the object to be processed, there is a problem in that the reactant gas and the carrier gas are suddenly heated near the object to be processed, which tends to cause turbulent flow between the two gases.

Therefore, the present invention has been made to solve the various problems mentioned above, and its purpose is to:
It is an object of the present invention to provide a vapor phase growth apparatus in which not only the generation of particles is almost completely suppressed, but also the apparatus can be simplified.

(Means for Solving the Problems) In the present invention according to the above object, the object to be treated is placed in a vapor phase growth apparatus that grows a film on the surface of the object by flowing a reactive gas over the surface of the object. ,
A reaction system that includes a hot plate that heats the object to be processed to a reaction temperature, an open chamber that is open around the hot plate, and a reaction gas that flows along the surface of the object to be processed in a direction parallel to the surface of the object. a gas supply nozzle; an inert gas supply nozzle for supplying an inert gas so as to form an inert gas curtain covering at least a side opposite to the object to be processed of the reaction gas flow; and a reaction gas flow and an inert gas flow. The present invention is characterized in that it includes a heating means for preheating the reaction gas and inert gas flowing from each gas supply nozzle to approximately the same temperature so that the gas forms a laminar flow.

(effect) Let's talk about the action.

The reaction gas is heated in advance and flows in a band shape from the reaction gas supply nozzle 24 along the surface of the wafer 22, and the N ₂ gas is heated in advance and is flowed in a band shape from the N ₂ gas supply nozzle 38 over the reaction gas. , a desired film can be formed on the surface of the wafer 22. In this case, since both gases have been heated to around the same temperature in advance, turbulent flow due to upward air currents etc. does not occur between the two gases, and therefore they are supplied in a laminar flow state. This prevents the reaction products generated from falling onto the surface of the wafer 22 and causing particles.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is an explanatory diagram showing an outline of the apparatus of the present invention.

20 is a hot plate, and a wafer 22 is placed on the top surface thereof. The hot plate 20 heats the wafer 22 to near the reaction temperature.

Of course, the hot plate 20 is supported by a suitable support (not shown),
The periphery of the hot plate 20 is open, and in the present invention, the reaction section including the hot plate 22 is called an open chamber.

Reference numeral 24 denotes a reaction gas supply nozzle, which is arranged on the side of the hot plate 20 and supplies the reaction gas to the wafer 2.
2 surface parallel to the wafer 22 surface.
The reaction gas supply nozzle 24 is connected to a hollow gas stopper 2.
6, and a gas supply pipe 32 is connected to a nozzle body 30 having a large number of slit-shaped or small hole-shaped gas jet ports 28 communicating with the gas stop 26 (FIGS. 1 and 2). . From the nozzle body 30, a band-shaped reactive gas flow having a thickness of several mm can flow along the surface of the wafer 22 in front of the nozzle body 30.

Reference numeral 34 denotes a reactant gas heating coil, which is wound around the gas supply pipe 32 at an appropriate position, and is used to heat the reactant gas in advance to near the surface temperature of the wafer 22 and pass it over the wafer 22 surface.

Reference numeral 36 denotes a discharge pipe disposed opposite to the reaction gas supply nozzle 24 with the wafer 22 in between, and discharges unreacted gas and reaction products in the gas phase.

Reference numeral 38 denotes an N ₂ gas supply nozzle, which is an inert gas supply nozzle, and is configured in substantially the same manner as the reaction gas supply nozzle 24, and is arranged above the reaction gas supply nozzle 24 to control the reaction gas flowing out from the reaction gas supply nozzle 24. This involves flowing N ₂ gas in a band over the top of the flow. This _N2 gas is also _N2 gas supply pipe 4
The heating coil 42, which is wound around zero, heats the reactant gas to approximately the same temperature as the reactant gas and supplies the reactant gas.

44 is an N ₂ gas discharge pipe for discharging the above N ₂ gas.

This embodiment is configured as described above.

In this way, the reaction gas is heated in advance and flows in a band shape from the reaction gas supply nozzle 24 along the surface of the wafer 22, and the N ₂ gas is heated in advance.
A desired film can be formed on the surface of the wafer 22 by flowing the reaction gas in a band form from the N ₂ gas supply nozzle 38 over the upper part of the reaction gas. In this case, since both gases have been heated to around the same temperature in advance, turbulent flow due to upward air currents etc. does not occur between the two gases, and therefore they are supplied in a laminar flow state, so the reactant gas vapor phase Reaction products generated therein will not fall onto the surface of the wafer 22 and particles will not be generated.

The reaction gas system is an inorganic silane system such as SiH ₄ --O ₂ system or SiH ₄ --PH ₃ --O ₂ system, and it is possible to form a SiO ₂ film or a PSG film.

In the above case, for example, in the SiH ₄ -O ₂ system,
If the reaction gas is preheated to a reaction temperature of approximately 400°C by the heating coil 34, it is conceivable that it will react within the reaction gas supply nozzle 24, for example. is heated to a temperature at which no reaction occurs, for example, about 200°C (N ₂ gas is also heated to about 200°C), and then heated to the reaction temperature near the wafer 22 by another suitable heating source. It is desirable to do so.

Example 1 SiH ₄ at 200℃, 400 c.c./min, O ₂ at 200℃, 600
cc/min, _N2 gas was supplied at 200℃, 2500c.c./min,
When the reaction was carried out at a reaction temperature of 400℃, a SiO ₂ film was formed.
Obtained at 1200 Å/min.

No particle formation was observed.

Note that the apparatus used was the apparatus schematically shown in FIGS. 1 to 3. Twelve 50 mm diameter wafers were arranged as shown in Figure 3. Each gas supply nozzle 2
The distance between 4, 38 and each gas exhaust pipe 36, 44 is approximately
I set it to 150mm. In addition, each gas supply nozzle 24,
The 38 jet ports were formed into a group of small holes each having a size of 0.3 mm and arranged in a row at intervals of 0.5 mm over a length of approximately 400 mm. As a result, each gas was supplied in a laminar flow with a thickness of several mm.

FIG. 4 shows yet another embodiment.

This embodiment is the same as the previous embodiment except that an ultraviolet irradiation lamp is provided.

The ultraviolet irradiation lamp 50 (Hg lamp) is provided above the N ₂ gas flow and irradiates the upper surface of the wafer 22 placed on the hot plate 20 with ultraviolet rays. 52 is a reflecting plate.

Reference numeral 54 denotes a box that houses the ultraviolet irradiation lamp 50, and _N2 gas is passed through the box 54. The reason why N ₂ gas is passed through the pocket 54 is that if O ₂ exists, ultraviolet rays will be absorbed by the O ₂ gas.

Reference numeral 56 denotes a cover made of quartz glass, and a chromium vapor-deposited film, for example, which does not transmit ultraviolet rays is formed on the peripheral edge of the cover 56, so that ultraviolet rays are irradiated onto the surface of the wafer 22 from a central transmitting portion.

In this embodiment, a reactive gas system excited by ultraviolet irradiation is preferably used.

For example, organic silane (tetraethoxysilane)
+O ₂ system, organic silane + PH ₃ (or organic phosphorus)
Reactive gas systems such as +O ₂ systems are useful.

Such organic silane systems generally do not react unless the temperature is 700°C or higher. However, the inventors believe that even in such organic silane systems,
It was discovered that by irradiating with ultraviolet rays, the reaction proceeded satisfactorily even at low temperatures of around 400°C.

The above fact is extremely useful in this embodiment. That is, the reaction gas and N ₂ gas can be preheated to about 400° C. and then supplied. This is because the reactive gas system does not react at this temperature, and the necessary reaction occurs only in the ultraviolet irradiation region of the ultraviolet lamp 50 to form a film on the wafer 22. In this way, the reaction gas and the N ₂ gas can be preheated and supplied to the reaction temperature of the reaction that occurs after the reaction gas, so no other heating source is required, and the reaction gas flow and the N ₂ gas can be flows in a laminar flow state, and the generation of particles can be suppressed as in the previous embodiment.

The reaction that occurs when the organic silane system is irradiated with ultraviolet light is a surface reaction that occurs on the surface of the object to be treated. Therefore, during the reaction, a film is formed on the concave portions as well as on the convex portions, resulting in excellent so-called step coverage (uniform adhesion).

Furthermore, in this embodiment, by placing an appropriate mask (not shown) slightly above the wafer 22, it is possible to grow a film on the wafer 22 according to the pattern of the mask. The mask is made of a material that transmits ultraviolet rays, such as quartz glass, and similarly to the cover 56, a portion that does not transmit ultraviolet rays is formed by chromium deposition or the like.

Example 2 Tetraethoxysilane at 200℃, 600c.c./min,
O ₂ gas at 200℃, 600c.c./min, N ₂ gas at 200℃,
Hg lamp (wavelength 184.9nm,
254.0nm) onto the wafer, and the reaction temperature was 400°C.
When the reaction was carried out at ℃, a SiO ₂ film was obtained at a rate of 1000 Å/min.

The apparatus used was the same as that used in Example 1, with the ultraviolet irradiation lamp shown in FIG. 4 attached. The distance between this ultraviolet irradiation lamp and the hot plate is 30
It was set to mm.

No particles were observed, and step coverage was good.

Furthermore, when a mask was placed slightly away from the wafer surface and ultraviolet rays were irradiated through the mask, a film could be selectively grown on the wafer according to the pattern of the mask.

In addition to the above, reaction systems include SiH ₄ -O ₂ system (reacts at room temperature when exposed to ultraviolet rays), SiH ₄ -
N ₂ O, CO ₂ , NO ₂ , NO, NH ₃ system (reacts at about 400°C with ultraviolet irradiation), organic silane - NO ₂ ,
CO ₂ , N ₂ O, NO, NH ₃ system (reacts at about 400℃)
A similar effect was obtained using .

In each of the above embodiments, an example of forming an N ₂ gas curtain was shown, but the invention is not limited to this.
Of course, argon or other inert gas can be used.

(Effects of the Invention) As described above, the present invention provides the following unique effects.

In other words, since a heating means is provided to heat the reaction gas and the inert gas to approximately the same temperature in advance, unlike sudden heating on the surface of the object to be treated, turbulent flow such as an upward current is generated in both gases. Don't let it happen,
Therefore, even if the chamber is provided as an open chamber instead of a closed chamber, a laminar flow of the reactant gas and the inert gas can be reliably obtained.

Since the chamber is an open chamber, not only can the entire device be made smaller and its cost reduced, but it also completely prevents the generation of particles, where reaction products adhering to the inner wall of the chamber fall and re-adhere to the film. can.

Since the reaction gas and the inert gas flow on the surface of the object to be treated in a laminar flow state, the reaction products in the gas phase are discharged together with the flow of the reaction gas. Therefore, the generation of particles is also suppressed in this respect.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the outline of the device of the present invention;
The figure is a plan view thereof, FIG. 2 is an explanatory diagram of a reaction gas supply nozzle, and FIG. 4 is an explanatory diagram showing another embodiment of the apparatus of the present invention. 20... hot plate, 22... wafer,
24... Reaction gas supply nozzle, 26... Gas stopper, 28... Gas spout, 30... Nozzle body,
32...Gas supply pipe, 34...Reaction gas heating coil, 36...Discharge pipe, 38... _N2 gas supply nozzle, 40... _N2 gas supply pipe, 42...Heating coil, 44... _N2 gas exhaust pipe, 50...ultraviolet irradiation lamp, 52...reflector, 54...box, 56...cover.

Claims (1)

[Scope of Claims] 1. In a vapor phase growth apparatus for growing a film on the surface of a workpiece by flowing a reaction gas over the surface of the workpiece, the workpiece is placed on the workpiece, and the workpiece is heated to a reaction temperature. an open chamber equipped with a hot plate to be heated and open around the hot plate; a reaction gas supply nozzle that flows a reaction gas along the surface of the object to be processed in a direction parallel to the surface of the object to be processed; and a flow of the reaction gas. an inert gas supply nozzle for supplying an inert gas so as to form an inert gas curtain covering at least the side opposite to the object to be treated; A vapor phase growth apparatus characterized by comprising heating means for heating a reaction gas and an inert gas flowing from each gas supply nozzle to approximately the same temperature in advance.