JPS6280272A - Vapor growth method - Google Patents

Abstract

PURPOSE:To provide a vapor growth device which is so constituted as to thoroughly prevent the generation of particles by passing inert gaseous flow to cover the reactive gaseous flow passed on the surface of a material to be treated in such a manner that both gases form thorough laminar flow and thoroughly discharging the resultant reaction product in the gaseous phase together with the gaseous flow. CONSTITUTION:The reactive gas is preliminarily heated 34 and is supplied 24 like a belt along the surface of a wafer 22 and preliminarily heated 42 gaseous N2 is passed like a belt to cover the upper part of the reactive gas so that the desired film is formed on the wafer 22 surface. Since both gases are preliminarily heated up to the temp. approximate to the surface temp. of the wafer 22, the generation of the turbulent flow by the ascending gaseous flow between both gases is obviated. Since the gases can be supplied in the laminar flow state, the fall of the resultant reaction product in the reactive gas onto the wafer 22 surface and the generation of the particles are obviated. A UV irradiation lamp 50 is moved back and forth on the wafer 22 and therefore, the film is successively formed by scanning the wafer 22 surface back and forth by the UV rays.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a vapor phase growth apparatus for the semiconductor industry.

(Prior Art) As shown in FIG. 5, a conventional vapor phase growth apparatus disperses a reaction gas in a reaction chamber (not shown) using a dispersion plate 12 arranged parallel to a susceptor 10. A device for vertically supplying a reaction gas toward the surface of the wafer 14, and a reaction chamber (not shown) as shown in FIG.
In the reaction tube 18, there is a device that supplies the reaction gas radially to the wafer 14 from the nozzle 16, or a device that flows the reaction gas in a direction parallel to the surface of the wafer 14 in the reaction tube 18 as shown in FIG.

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

That is, in the apparatuses shown in FIGS. 5 and 6, gas-phase reaction products (particles) generated in the reaction gas and reaction products attached to the wall of the chamber are carried by the flow of the reaction gas. Another problem is the generation of so-called particles that fall and adhere to the film grown on the surface of the object to be treated due to the blowing up of the reaction gas. Further, in the apparatus shown in FIG. 6, there is a problem in that reaction products adhere to the nozzle 16, causing the nozzle 16 to become clogged.

In the apparatus shown in FIG. 7, although the gas phase reaction products generated in the reaction gas are relatively easily discharged along with the reaction gas flow, the reaction gas flow is generally supplied in a turbulent state. (The reaction gas is heated near the wafer 14, resulting in a more turbulent state), so the particles generated in the gas phase still fall and adhere to the grown film on the wafer 14, generating particles. I sometimes see it. Further, the reaction products adhering to the inner wall of the reaction tube 18 are peeled off by the turbulent flow of the reaction gas, and inevitably generate particles that fall and adhere to the film.

Therefore, in order to solve the above problem, the inventors supplied a reaction gas flow in a band shape along the surface of the object to be treated, and also flowed a N2 gas curtain flow in a band shape covering the outside of the reaction gas flow to improve the reaction system. By blocking the outside world, reaction products are prevented from adhering to the inner wall of the chamber, and by flowing the above reaction gas flow and N2 gas curtain flow in a laminar flow state, the reaction products grown in the gas phase can be removed. He has devised a vapor phase growth method that can almost completely suppress the generation of particles by transporting them out of the system, and has already applied for a patent.

The present application further improves the invention of the above-mentioned application, and its purpose is to make it possible to bring the reaction gas flow and the N2 gas into an almost completely laminar flow state, thereby further reliably preventing the generation of particles. It is an object of the present invention to provide a vapor phase growth apparatus which not only allows for the growth of a film in a desired pattern on the surface of an object to be treated, but also enables the apparatus to be miniaturized.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes the following configuration. That is, 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 reactive gas supply nozzle that causes the reactive gas to flow along the surface of the workpiece in a direction parallel to the workpiece surface, and an inert gas curtain that covers at least the opposite side of the workpiece to form an inert gas curtain. an inert gas supply nozzle for supplying an active gas; a heating means for heating the reaction gas and the inert gas to a temperature approximately equal to the surface temperature of the object to be treated; and an ultraviolet irradiation device for irradiating the surface of the object with ultraviolet rays. It is characterized by comprising a lamp and a reciprocating mechanism that relatively reciprocates the ultraviolet irradiation lamp and the object to be treated in parallel planes.

(Function) As described above, the inert gas flow is supplied covering the reaction gas, but since the reaction gas and the inert gas are heated in advance to approximately the same temperature by the heating means, the reaction gas flow is turbulent flow between the inert gas flow and the inert gas flow,
Neither one of them causes an updraft, and both are supplied in a laminar flow. Therefore, the reaction products generated in the gas phase are discharged together with the exhaust gas, thereby preventing the generation of particles.

In this way, the reaction gas flow and the inert gas flow are heated in advance to near the surface temperature of the object to be treated, that is, near the reaction temperature, but this reaction temperature is increased by adding the conditions of ultraviolet irradiation, and the reaction temperature is increased. Because the reaction temperature is 100%, there is no ultraviolet irradiation and no reaction occurs until it reaches the object to be treated.Furthermore, it is maintained at the reaction temperature, creating a completely laminar flow and reliably preventing the generation of particles. be done.

In addition, the organic silane-0□ system reacts at low temperatures as described above when irradiated with ultraviolet rays, and this reaction is mainly a surface reaction, so by using an appropriate mask, a film in a desired pattern can be formed on the surface of the object to be treated. Can be grown selectively.

By the way, as the ultraviolet irradiation lamp is reciprocated over the object to be treated, a film is formed in a band-like manner sequentially from one edge of the object to the other as the ultraviolet irradiation lamp moves. By reciprocating the ultraviolet irradiation lamp over the object to be treated, the ultraviolet irradiation conditions are made uniform over the entire surface of the object to be treated, and uniform growth of the film becomes possible.

(Embodiments) Preferred embodiments of the present invention will be described in detail below with reference to 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 of the hot plate.
of! ! place The hot plate 20 heats the wafer 22 to near the reaction temperature.

24 is a reaction gas supply nozzle, and the hot plate 20
It is arranged laterally to flow the reactant gas along the wafer 22 surface and parallel to the wafer 22 surface. Reaction gas supply nozzle 2
4 has a hollow gas stop 26, and this gas stop 26
A gas supply pipe 32 is connected to a nozzle body 30 having two gas outlets in the form of a large number of slits or small holes communicating with each other (FIGS. 1 and 2). From the nozzle body 30, a band-shaped reactive gas flow having a thickness of several dragons 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 location, heats the reactant gas to a temperature close to the surface temperature of the wafer 22, and causes the reactant gas to pass over the surface of the wafer 22.

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 layer.

38 is an N2 gas supply nozzle which is an inert gas supply nozzle, and is configured almost the same as the reaction gas supply nozzle 24,
It is arranged above the reaction gas supply nozzle 24 and flows N2 gas in a band shape over the reaction gas flow flowing out from the reaction gas supply nozzle 24. This N2 gas is also N
The heating coil 42 wound around the two-gas supply pipe 40 heats the gas to approximately the same temperature as the reaction gas and supplies the gas.

44 is a N2 gas discharge pipe for discharging the above N2 gas. Reference numeral 43 denotes a shielding plate that blocks both sides of the front side of the reaction gas supply nozzle 24 and the N2 gas supply nozzle 38. The shielding plate 43 blocks both gas flows and surrounding stagnant air. It is preferable that the shielding plate 43 is made up of a hot plate, for example, and is heated to the same temperature as that of both gas flows. Reference numeral 50 is an ultraviolet irradiation lamp (Hg lamp). It is provided to extend in a direction perpendicular to the flow direction. This ultraviolet irradiation lamp 50
teeth,! The device irradiates the upper surface of the wafer 22 placed on the hot plate 20 with ultraviolet rays from above the l12 gas flow. It irradiates it with ultraviolet light.

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 N2 gas is passed through the box 54 is that ultraviolet rays are absorbed by the 0□ gas.

The box 54 is adapted to be reciprocated in the direction of gas flow in a plane parallel to the hot plate 20 by a suitable reciprocating drive (not shown). As a result, the surface of the wafer 22 is sequentially irradiated with ultraviolet rays from the ultraviolet irradiation lamp 50 in a band-like manner back and forth from one edge to the other edge.

The reciprocating drive device described above can be configured by, for example, a rail device that slideably guides both ends of the box 54 within a horizontal plane, and a forward/reverse motor that drives the box 54 back and forth along the rail device.

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 can pass through the central transmission part and irradiate the surface of the wafer 22. ing.

This embodiment is configured as described above.

Thus, the reaction gas is heated in advance and flows from the reaction gas supply nozzle 24 in a band shape along the surface of the wafer 22.
4, the reaction gas is flowed in a band shape over the wafer 2.
A desired film can be formed on the two surfaces. In this case, since both gases are heated to near the surface temperature of the caustic wafer 22, turbulent flow due to upward airflow etc. does not occur between the two gases, and therefore the reactant gas is supplied in a laminar flow state. A situation such as reaction products generated in the phase falling onto the surface of the wafer 22 and generation of particles does not occur. Since there are shielding plates 43 on the sides of both gas flows that block both gas flows from surrounding stagnant air, the surrounding stagnant air is not caught up in both gases, and the laminar flow of both gas flows is prevented. The condition is suitably maintained.

The reaction gas system is organic silane (tetraethoxysilane) +
Reactive gas systems such as 0□ system, organic silane + PH's (or organic phosphorus) + 0□ system are useful.

Such organic silane systems generally do not react unless the temperature is 700°C or higher. However, the inventor
It has been found that even in such an organic silane system, the reaction can proceed satisfactorily even at a low temperature of about 400° C. by irradiating it with ultraviolet rays.

The above fact is extremely useful in this embodiment. That is, the reaction gas and N2 gas can be preheated to about 400° C. and then supplied. At this temperature, the reactive gas system does not react, and for the first time in the ultraviolet irradiation area of the ultraviolet lamp 50,
This is because a necessary reaction occurs and a film is formed on the wafer 22. In this way, the reaction gas and N2 gas can be preheated and supplied to the reaction temperature of the reaction that occurs after the reaction gas, so there is no need for any other heating source, and the reaction gas and N2 gas flow in a laminar flow. It is possible to ensure that the generation of particles is suppressed.

In the present invention, since the ultraviolet irradiation lamp 50 is moved back and forth over the wafer 22, the ultraviolet rays are scanned back and forth over the wafer 22 in a band-like manner, and a film is sequentially grown. In this case, since the ultraviolet irradiation lamp 50 consisting of one or two discharge tubes reciprocates and irradiates the wafer 22 with ultraviolet rays, dozens of fixed discharge tubes with slightly different discharge characteristics are used. This makes it possible to irradiate much more uniformly than irradiating multiple wafers individually, and it is possible to grow a film to a uniform thickness.

Next, the reaction that occurs when the organic silane system is irradiated with ultraviolet rays is a surface reaction that occurs on the surface of the object to be treated. Therefore, in this reaction, a film grows 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 also 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.

In addition to the above, the reaction system in this example is 5iH4=O□
system (reacts at room temperature by ultraviolet irradiation), 5i) I
.

NzO, COz, NOz, No, NH3 system (reacts at about 400℃ with ultraviolet irradiation), organic', i
'y 7- No2. Co2°N20. NO, Nt
h, system (reacts at about 400° C.), etc. are useful.

In the above embodiment, the hot plate 1-20 is fixed and the ultraviolet irradiation lamp 50 is moved back and forth, but the same effect can be achieved even if the hot plate 20 is moved back and forth and the ultraviolet irradiation lamp 50 is fixed. It has the following effects. Alternatively, both the hot plate 20 and the ultraviolet irradiation lamp 50 may be set to move back and forth.

As another example, as shown in FIG. 4, a hot plate 20 is provided rotatably at an angle of 90 degrees (or any angle), and an ultraviolet lamp is reciprocated in the X direction to perform vapor phase growth. After that, by rotating the real plate 20 906 times and reciprocating the ultraviolet lamp (which means reciprocating in the Y direction), the ultraviolet rays can be scanned vertically and horizontally on the wafer, ensuring a uniform coating. Growth can be further promoted.

(Effects of the Invention) As described above, according to the apparatus of the present invention, it is possible to flow the N2 gas flow over the reaction gas flow flowing on the surface of the workpiece so that both gas flows form a completely laminar flow state. Therefore, the reaction products in the gas phase are completely discharged along with the gas flow, and since the reaction products do not adhere to the inner wall of the reaction chamber and fall as in the conventional method, particle generation can be completely prevented. It can be prevented.

Furthermore, it is possible to uniformly grow the film, and by using an appropriate mask, it is possible to selectively grow a film in a desired pattern on the surface of the object to be treated.

Furthermore, the ultraviolet irradiation lamp can be composed of one or two discharge tubes, making the lamp house much more compact, and compared to conventional equipment, there is no need to necessarily provide a reaction chamber, simplifying the overall equipment. It can be configured as follows, and has various effects such as a significant reduction in cost.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the outline of the apparatus of the present invention, Fig. 3 is an explanatory plan view thereof, Fig. 2 is an explanatory diagram of the reaction gas supply nozzle, Fig. 4 is an explanatory diagram when rotating the hot plate, 5
7 to 7 are explanatory diagrams each showing a conventional vapor phase growth apparatus. 10... Susceptor, 12... Dispersion plate, 14...
... Wafer, 16... Nozzle, 18... Reaction tube, 20... Hot plate, 22...
・Wafer, 24... Reaction gas supply nozzle,
26... Gas stopper, 28... Gas outlet,
30... Nozzle generally, 32... Gas supply pipe,
34... Reaction gas heating coil, 36...
Discharge pipe, 38...N2 gas supply nozzle, 40...
・＼2 Gas supply pipe, 42...Heating coil, 4
3... Shielding plate, 44... N2 gas exhaust pipe, 5
0... Ultraviolet irradiation lamp, 52... Reflector plate,
54...Box, 56...Cover.

Claims (1)

[Claims] 1. In a vapor phase growth apparatus that grows a film on the surface of a workpiece by flowing a reaction gas over the surface of the workpiece, the reaction gas is passed along the surface of the workpiece in parallel with the surface of the workpiece. an inert gas supply nozzle that supplies the inert gas so as to form an inert gas curtain covering at least the side opposite to the object to be treated of the reaction gas flow; a heating means for preheating an active gas to a temperature approximately equal to the surface temperature of the object to be treated; an ultraviolet irradiation lamp for irradiating the surface of the object with ultraviolet rays; 1. A vapor phase growth apparatus comprising: a reciprocating mechanism for relatively reciprocating movement in a reciprocating manner.