JPH0719143Y2 - CVD apparatus having gas introduction device - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a thin film forming apparatus for forming a predetermined vapor phase growth layer on a plurality of semiconductor substrates, and more particularly to a thin film forming apparatus having a gas introducing device for forming a predetermined gas concentration gradient in a reaction tube.

[Prior art]

In manufacturing a semiconductor device, a CVD (vapor phase growth) apparatus is used to form a thin film such as an oxide film or polycrystalline silicon on a semiconductor substrate. This CVD apparatus includes a vertical CVD apparatus in which semiconductor substrates are vertically stacked and a horizontal CVD apparatus in which semiconductor substrates are arranged side by side. In a vertical CVD apparatus, a semiconductor substrate housed inside a reaction tube made of quartz or the like is heated from the outside and a gas is introduced into the inside from the lower end of the reaction tube. The gas flows toward the upper end and reacts on the plurality of semiconductor substrates. However, since the reaction sequentially occurs from the semiconductor substrate on the upstream side to the semiconductor substrate on the downstream side, the gas concentration in the downstream is gradually diluted. Therefore, the thickness of the thin film formed on the substrate tends to become thinner along the direction of gas flow, that is, it has an inclination along the direction of gas flow. This is
A gas may be used for the purpose of introducing impurities.
That is, the concentration of impurities in the film on the substrate has a slope along the gas flow. In order to solve this problem, a gas introducing device called an injector was installed in the CVD device (for example, the actual development Sho-60-18541, the actual development Sho-62-160537, the actual development Sho-61-190335). reference). A typical conventional CVD apparatus incorporating such a gas introduction apparatus is shown in FIG. The CVD apparatus 20 shown in FIG. 3 is basically provided with a reaction tube 22 inside the heating coil 21, and an inner tube inside the reaction tube 22.
23 are provided. In the inner tube 23, a supporting device 25 that supports a plurality of semiconductor wafers 24 in parallel is installed.
The support device 25 is arranged on the CVD device 20 by opening and closing the door 26. Gas is introduced into the CVD device 20 by an injector 30. The injector 30 is a hollow tube, and the inner tube 23 and the supporting device are
A gas source (not shown) extends upward between
Are linked to. The injector 30 is provided with a plurality of holes 31 through which gas flows. The size of the holes 31 and the spacing between them are determined so that the thickness of the thin film to be formed on the wafer, or the gas concentration at which the concentration of impurities in the thin film is desired, is achieved. . Gas is introduced into the injector 30 from a gas source, passes through the hole 31 and undergoes the necessary reaction on the wafer. Then, the unnecessary gas is discharged through the reaction tube 22 and the inner tube 23.

[Problems to be solved by the device]

However, the CVD apparatus using such an injector has the following drawbacks. If an injector is used, the total amount of gas to be introduced can be controlled, but the size of the holes provided in the injector and the spacing between them cannot be changed once determined. On the other hand, the gas concentration in the reaction tube 22 changes depending on the flow rate and temperature of the gas, the size and number of wafers, the processing time, and the like. Therefore, it is necessary to replace the injector with the required hole size and spacing to achieve the desired gas concentration on each substrate.
However, since the injector is fixedly attached to the CVD device, such replacement is virtually impossible. Then, the objective of this invention is to provide the CVD apparatus incorporating the gas introduction apparatus which made the injector removable. Further, another object of the present invention is to provide the above-mentioned CVD apparatus incorporating a gas introduction apparatus having a detachable injector, which has an opening capable of adjusting an outflow amount of gas.

[Means for Solving Problems]

In order to achieve the above object, the present invention provides an injector having a plurality of holes for supplying a gas into a reaction tube in a CVD apparatus, and a detachable injector end for introducing the gas into the injector. And a holder having an opening through which a gas can pass, and a gas introduction device including the holder. This holder has an adjusting device for adjusting the flow rate of the gas flowing out from the opening to a predetermined flow rate. The vapor phase growth equipment used here can be either a vertical CVD equipment or a horizontal CVD equipment.
It may be a VD device.

[Action]

The gas introduction device provided in the CVD device of the present invention forms a desired gas concentration according to semiconductor processing in the reaction tube by arranging holes having a predetermined size and injectors having a space between the holes for convenience. To do. Further, the holder of the gas introduction device provided in the other CVD device of the present invention has a gas outflow opening, and by adjusting the amount of the gas outflowing from the opening, the inside of the reaction tube can be further adjusted according to the desired semiconductor processing. Form a gas concentration of.

【Example】

Next, an embodiment of the present invention will be described with reference to the drawings. First
The figure shows a partial cross-sectional view of the inside of the vertical CVD apparatus 1 in which a gas introduction device is installed. This gas introduction device can also be applied to a horizontal CVD device. The gas introduction device 2 comprises a holder 3 and an injector 15, and the holder 3 is installed near the bottom of the CVD device. An injector 15 is detachably attached to the upper end of the holder 3, and an opening 4 is provided below the injector 15. The injector 15 is a hollow body, typically made of quartz, having a plurality of holes 16 spaced along its length to allow gas passing therethrough to exit through the holes 16. ing. The size of the holes and the distance between the holes are determined according to the number of wafers, the size, and the reaction conditions. An injector can be detachably attached to the holder 3, so that the injectors having the hole sizes and the intervals determined according to various conditions are prepared, and the wafer supporting device 25 is arranged in the reaction tube 22. At times, select the most suitable injector and attach it to the holder 3. By making the injector detachable in this way, not only can a desired gas concentration be achieved in the reaction tube 22, but when the injector is contaminated by deposits, the injector can be removed from the CVD apparatus and cleaned. FIG. 2 shows a partially enlarged view of the holder 3 attached to the CVD device. Since the upper part of the reaction tube of the vertical CVD apparatus has a high temperature, the injector 15 must be made of a material that can withstand this. However, since the bottom part of the reaction tube has a relatively low temperature, the holder 3 has good workability and strength. It can also be made of a metal that is advantageous in terms of. This can be done by separating the gas introduction device 2 into the injector 15 and the holder 3. The holder 3 is horizontally attached to the CVD apparatus and includes a horizontal portion 5 connected to a gas source, an upper portion 6 extending upward, and a lower portion 7 extending further downward. The upper part 6 of the holder 3 is expanded and its inner diameter is
Injector 15 is detachable to accommodate a part of the end
It has the same outer diameter as 15. An opening 4 is provided on the side of the lower portion 7 of the holder 3 facing the support device 25 (see FIG. 3). A threaded portion 8 is formed around the inside of the lower portion 7, and an adjusting screw 10 having a threaded portion 9 corresponding to the threaded portion 8 is screwed into the lower portion 7. When the adjusting screw is screwed in further, the adjusting screw 10 can reduce the effective area of the opening 4. Conversely, reversing the adjusting screw can increase the effective area of the opening 10. Therefore, the flow rate of the gas flowing out through the opening 10 can be adjusted by the adjusting screw. In this embodiment, the adjusting screw adjusts the gas flow rate, but the present invention is not limited to this. For example, it may have a structure like a gas plug used at home. The gas guided to the holder 3 is divided into gas directed to the upper portion 6 and gas directed to the lower portion 7. The gas towards the upper part 6 flows into the injector 15 and then through each hole 16 into the reaction tube. The gas heading towards the lower part 7 flows through the opening 4 into the reaction tube. The flow rate of the gas flowing through the opening 4 can be adjusted by the adjusting screw as described above. Therefore, the gas flowing into the reaction tube 22 can be appropriately adjusted by adjusting the total amount of gas and the adjusting screw.

【effect】

The present invention has the above effects because it is configured as described above. Since the injector of the gas introduction device is removable, it can be replaced with an injector having a hole size and a space between holes that can achieve a gas concentration suitable for a desired process. Also,
Even when the injector is contaminated with deposits or the like, it can be replaced as appropriate. Furthermore, since the flow rate of gas from the holder opening can also be adjusted by adjusting the adjusting screw, the gas concentration distribution required for each of the multiple wafers supported by the supporting device can be combined with the adjustment of the total amount of gas. Can be achieved.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a vertical CVD apparatus incorporating a gas introducing device according to the present invention. FIG. 2 is a partially enlarged sectional view showing a holder of the gas introducing device. FIG. 3 is a schematic sectional view of a vertical CVD apparatus incorporating a conventional injector.

[Explanation of main symbols]

 1 ... Vertical CVD device, 2 ... Gas introduction device 3 ... Holder, 4 ... Opening 5 ... Horizontal part, 6 ... Upper part 7 ... Lower part, 10 ... Adjusting screw 15 ... Injector, 16 ... hole

Claims (1)

[Scope of utility model registration request] 1. A CVD apparatus for accommodating a plurality of semiconductor substrates arranged in parallel inside a reaction tube and supplying gas to form a vapor phase growth layer on the semiconductor substrate, for supplying gas to the reaction tube, An injector having a plurality of holes through which a gas flows out, which extends along the reaction tube, and a holder for detachably housing the open end of the injector for introducing the gas into the injector. A device is provided, wherein the holder has a gas supply part connected to a gas source, a mounting part for accommodating the end of the injector extending from the gas supply part, and an opening through which the gas expanded from the gas supply part can flow out. And a gas flow rate adjusting means is provided at the opening, the gas flows from the gas source to the injector through the gas supply section and the mounting section, and It can flow out from the opening of the gas outlet portion through the scan supply unit, CVD apparatus characterized by.