JPH0631139U - Vertical low pressure CVD equipment - Google Patents

Abstract

(57) [Summary] [Purpose] A vertical decompression system that prevents corrosion of the metal manifold that fixes the furnace core tube and the cap / elevator even when a corrosive gas is used as the raw material gas, and extends the service life. A CVD apparatus is provided. [Structure] A gas introduction pipe 11 for introducing N ₂ gas as a purge gas is provided so as to penetrate a side wall of the manifold 4 and open between the outer tube 2 and the inner tube 3 upward. A pipe 14 is connected to the gas introduction pipe 11. This tube 14 has a plurality of holes 15 on its upper surface side so that N ₂ gas can be uniformly supplied in the circumferential direction of the inner tube 3. Therefore, if the N ₂ gas is continuously supplied during and after the wafer processing, the stagnation of the raw material gas disappears and the manifold 4 and the cap / elevator 8 are not corroded.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

This invention relates to a vertical decompression CVD (C hemical V ap or D eposition) apparatus for performing a film forming process on the wafer, about a vertical, down-pressure CVD apparatus used in particular corrosive gas as a source gas.

[0002]

[Prior art]

 FIG. 3 is a schematic diagram showing the structure of such a vertical low pressure CVD apparatus. In the figure, reference numeral 20 denotes a furnace core tube having a double tube structure including an outer tube 2 made of quartz and a cylindrical inner tube 3 made of quartz provided in the outer tube 2. A heater 1 for heating the film during the film forming process is arranged around the furnace core tube 20. The lower ends of the furnace core tube 20 (outer tube 2 and inner tube 3) are fixed to a metal manifold 4. Further, an exhaust port 5 for exhausting the inside of the furnace core tube 20 is provided in the manifold 4 in a manner of communicating with the furnace core tube 20. Since the manifold 4 fixes each of these members, its material is limited to metal, and other materials cannot be used.

A metal cap / elevator 8 that can be raised and lowered is installed below the manifold 4, and the cap / elevator 8 is mounted on the cap / elevator 8 during film formation processing. A heat insulating cylinder 10 and a heat insulating cylinder 7, both of which are made of quartz, are provided in this order in order to prevent heat radiation. A quartz mounting table 6 on which a wafer 9 to be processed is mounted is installed on the heat insulating cylinder 7. The loading / unloading of the wafer 9, the mounting table 6 and the heat insulating cylinder 7 to / from the furnace core tube 20 is controlled in accordance with the vertical movement of the cap / elevator 8.

FIG. 4 is a partially enlarged cross-sectional view showing a layout of a conventional gas introduction pipe, showing a film forming process. A gas introduction pipe 11 for introducing N ₂ gas as a purge gas is provided so as to penetrate the side wall of the manifold 4 and to open upward between the outer tube 2 and the inner tube 3. Further, gas introduction pipes 12 and 13 for introducing gases such as SiH ₂ Cl ₂ and NH ₃ which are raw material gases penetrate the side wall of the manifold 4 and pass under the lower end portion of the inner tube 3 and inside the inner tube 3. It is arranged so as to open upward.

Next, the operation during the film forming process will be described. The wafer 9 is placed on the mounting table 6, the cap / elevator 8 is lifted in the direction of the hollow arrow shown in FIG. 3, and the wafer 9, the mounting table 6 and the heat retaining tube 7 are loaded into the furnace core tube 20. To do. The inside of the furnace core tube 20 is maintained at a predetermined degree of vacuum by evacuation from the exhaust port 5 and the inside of the furnace core tube 20 is maintained at a predetermined temperature by heating the heater 1, and then the gas is introduced through the gas introduction tubes 12 and 13. The raw material gas is introduced into the furnace core tube 20, and the wafer 9 on the mounting table 6 is subjected to film formation processing. After performing the film forming process, N ₂ gas is introduced through the gas introducing pipe 11 and N ₂ gas purging is repeated several times to exhaust the raw material gas remaining in the furnace core tube 20. Finally, the cap / elevator 8 is lowered to take out the film-formed wafer 9 out of the furnace core tube 20 to complete the film-forming process operation.

By the way, a corrosive gas (eg, chlorine-based gas) is often used as a raw material gas in the film forming process, and the cap / elevator 8 is lowered with the raw material gas remaining in the furnace core tube 20. Then, moisture in the atmosphere reacts with the raw material gas to generate a highly corrosive substance (eg, hydrochloric acid), which may result in corrosion of the metal manifold 4 and the cap / elevator 8. It was Therefore, the raw material gas is exhausted by N ₂ gas purge several times.

[0007]

[Problems to be solved by the device]

However, in the exhaust treatment of the raw material gas by several times of N ₂ gas purging in the conventional apparatus, since the N ₂ gas gas introduction pipe 11 has only one introduction port, it is surrounded by the manifold 4, the heat insulating cylinder 7 and the cap / elevator 8. The raw material gas stagnating in the damaged part cannot be exhausted sufficiently, and the metal manifold 4 and the cap / elevator 8 are corroded, resulting in a problem that the service life is short.

The present invention has been made in view of the above problems, and a plurality of holes for uniformly introducing N ₂ gas for back purging into the furnace core tube is provided between the outer tube and the inner tube. By providing a ring-shaped tube with a valve, even when a corrosive gas is used as a source gas for film formation, corrosion of the manifold and cap / elevator can be prevented, and the service life of the device can be extended. It is an object of the present invention to provide a vertical type low pressure CVD apparatus that can be used.

[0009]

[Means for Solving the Problems]

 The vertical decompression CVD apparatus according to the present invention carries a wafer to be processed placed on a mounting table into a furnace core tube equipped with an outer tube and an inner tube, and introduces a raw material gas into the furnace core tube. Between the outer tube and the inner tube in a vertical depressurization CVD apparatus that performs a film forming process on the wafer and introduces a purge gas into the furnace core tube to exhaust the residual raw material gas in the furnace core tube. A ring-shaped tube having a plurality of holes is provided, and the purge gas is introduced into the furnace core tube from the tube.

[0010]

[Action]

The vertical decompression CVD apparatus of the present invention is provided with a ring-shaped tube having a plurality of holes between the outer tube and the inner tube, and can supply N ₂ gas uniformly in the circumferential direction. Even if a corrosive gas is used, it is possible to prevent corrosion of the manifold and cap / elevator and adhesion of deposits even if a corrosive gas is used.

[0011]

【Example】

 Hereinafter, the present invention will be specifically described with reference to the drawings showing an embodiment thereof. FIG. 1 is a partially enlarged cross-sectional view showing a layout of a gas introduction pipe of a vertical decompression CVD apparatus according to the present invention, showing a film forming process. In the figure, 2 and 3 are an outer tube and an inner tube made of quartz, respectively, the outer tube 2 is provided to maintain a vacuum state in the furnace, and the inner tube 3 is a deposit on the inner wall of the outer tube 2. It is provided to prevent the adherence. The lower end of the outer tube 2 and the lower end of the inner tube 3 are fixed to a metal manifold 4. And the purge gas N ₂ A gas introduction pipe 11 for introducing gas is provided so as to penetrate the side wall of the manifold 4 and open upward between the outer tube 2 and the inner tube 3. In addition, the raw material gas, SiH₂Cl₂， NH₃Gas introduction pipes 12 and 13 for introducing gas such as are provided so as to penetrate the side wall of the manifold 4, pass under the lower end of the inner tube 3 and open upward in the inner tube 3. There is.

A metal cap / elevator 8 that can move up and down is installed below the manifold 4, and the cap / elevator 8 and the manifold 4 are hermetically sealed. On the cap / elevator 8, a quartz heat insulating tube 10 and a heat insulating tube 7 are provided in this order in order to prevent heat radiation to the cap / elevator 8 during the film forming process.

FIG. 2 is a schematic view showing the pipe 14 connected to the gas introduction pipe 11, FIG. 2 (a) is a side view thereof, and FIG. 2 (b) is a top view thereof. A hole that fits into the gas introduction pipe 11 is formed at one location of the ring-shaped pipe 14, and the pipe 14 and the gas introduction pipe 11 are connected to each other. A plurality of holes 15 are formed in the circumferential direction on the upper surface side of the pipe 14.

In the vertical decompression CVD apparatus of the present invention, since the tube 14 having the plurality of holes 15 is connected to the gas introduction tube 11, if the N ₂ gas is continuously supplied during and after the wafer processing, the raw material gas is not supplied. Even if a corrosive gas is used as the raw material gas, the metal manifold 4 and the cap / elevator 8 will not be corroded. The outer tube and inner tube are required to have properties such as no contamination by heavy metals, no generation of dust such as particles, and high temperature resistance. Although the rise of SiC has been seen in recent years, quartz is currently the most desirable in terms of purity. Further, if the gas introduction pipe 11 and the pipe 14 are integrated, they cannot be installed in the manifold 4, and therefore they must be removable. And this connection does not have to be a contacting method such as frosted glass bonding as long as gas can be introduced.

[0015]

[Effect of device]

As described above, in the vertical decompression CVD apparatus of the present invention, the ring-shaped tube having a plurality of holes is provided between the outer tube and the inner tube, and the N ₂ gas is evenly distributed in the circumferential direction. Since it can be supplied, the stagnation of the raw material gas can be eliminated, and even when a corrosive gas is used, the corrosion of the manifold and the cap / elevator and the adhesion of deposits can be prevented, and the film formation process can be performed efficiently. Further, the present invention has excellent effects such as a longer life of the device.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view showing a layout of a gas introduction pipe of a vertical decompression CVD apparatus according to the present invention.

FIG. 2 is a schematic view showing a pipe connected to a gas introduction pipe.

FIG. 3 is a schematic diagram showing the configuration of a vertical low pressure CVD apparatus.

FIG. 4 is a partially enlarged cross-sectional view showing an arrangement mode of a conventional gas introduction pipe.

[Explanation of symbols]

 2 Outer tube 3 Inner tube 4 Manifold 5 Exhaust port 6 Mounting table 7 Heat-insulating cylinder 8 Cap / elevator 9 Wafer 10 Insulating cylinder 11, 12, 13 Gas introduction pipe 14 Pipe 15 hole 20 Furnace core pipe

Claims (1)

[Scope of utility model registration request] 1. A wafer to be processed placed on a mounting table is loaded into a furnace core tube having an outer tube and an inner tube, and a source gas is introduced into the furnace core tube to perform a film forming process on the wafer. In a vertical decompression CVD apparatus for performing a purge gas introduction into the furnace core tube to exhaust the residual raw material gas in the furnace core tube, a ring-shaped ring having a plurality of holes between the outer tube and the inner tube. A vertical decompression CVD apparatus comprising a pipe, and being configured to introduce the purge gas into the furnace core pipe from the pipe.