JPH0322521A - Vapor growth device and method thereof - Google Patents

Abstract

PURPOSE:To improve the distribution of film thickness by a method wherein inside of an exhaust pipe is divided into a plurality of chambers in axial direction, these chambers are independently controlled in exhaust speed and exhaust time, and a reaction chamber is uniformly exhausted in vertical direction. CONSTITUTION:An exhaust pipe 4 is divided into four parts in vertical direction using partition walls P, each of the four parts can be exhausted independently. The divided chambers of the exhaust pipe 41, 42, 43 and 44 are collectively connected to a pump Pu through valves VA, VB, VC and VD. By adjusting the valves VA to VD, the quantity of exhaust of each chamber, distribution of film thickness of the upper and lower wafer can be controlled.

Description

[Detailed description of the invention] [Summary] Vapor phase growth (CVD) used for shrimp layers or certain films of various coatings
Regarding the apparatus and method, the aim is to obtain an apparatus that does not impair the uniformity of the film property distribution under a wide range of growth conditions, especially in epitaxial growth performed under atmospheric pressure or near normal pressure. a plurality of susceptors arranged in the reaction chamber and carrying long wafers; A gas introduction pipe for introducing a reaction gas into the reaction chamber, and an exhaust pipe provided at a position opposite to the gas introduction pipe with the susceptor in between and having an opening for exhausting the reaction chamber (1) The exhaust pipe The tubes are arranged in parallel around the susceptor and are comprised of a plurality of individual exhaust tubes each having the opening at a different location.

(2) Using a structure in which the exhaust pipe is divided into a plurality of chambers in the direction of the pipe axis and can exhaust air independently from each chamber, the exhaust time or exhaust speed of the exhaust system that exhausts each chamber is adjusted so that each chamber is The structure is designed to equalize the amount of exhaust gas.

[Industrial Field of Application] The present invention is directed to vapor-phase growth (
CVD) apparatus and method.

The CVO apparatus of the present invention can be used to form layers such as a thin layer, a conductive layer, and an insulating layer on a substrate in a wafer process for manufacturing semiconductor devices.

Recent shrimp CVD equipment (CVD equipment in a broad sense including epitaxial growth equipment) is capable of high throughput and large diameter wafer processing. Uniformity in the distribution of film properties (film quality and film thickness) is desired.

Therefore, the device itself was made larger. Furthermore, there is a need for an apparatus that allows wafers to be processed to be arranged in a dense manner within the apparatus and that provides good uniformity.

[Prior art] In the conventional shrimp/CVD equipment. In order to make the film thickness distribution uniform, the wafer was rotated and the reaction gas was supplied and exhausted as follows.

Figure 3 is a schematic cross-sectional view of a conventional shrimp/CVD device. FIG. 4 is a plan view thereof.

In the figure, a large number of susceptors 2 are vertically arranged and held in a reaction chamber 1, and a reaction gas is introduced into the chamber through a gas introduction pipe 3 and exhausted through an exhaust pipe 4, controlling the gas flow rate and exhaust speed. Adjust to maintain a predetermined gas pressure in the reaction chamber.

The susceptor 2 has a structure that allows it to rotate around a rotating shaft 5 while maintaining an airtight seal.

The susceptor 2 is heated by induction from the outside of the reaction chamber 1 by an RF coil 7.

The gas introduction pipe 3 is. It is provided at a position facing the exhaust pipe 4 with the susceptor 2 in between.

However, in the conventional example, there is only one exhaust pipe, and in such an exhaust pipe, the gas flow rate is determined by the pressure difference between the inside and outside of the pipe, and the pressure distribution inside the pipe in the vertical direction depends on the pipe diameter and the number of holes. Depends on size and location. The pressure inside the pipe is high at the top and low at the bottom.

Therefore, it was difficult to control the distribution of film properties in the vertical direction within the reaction chamber. Particularly when the reaction chamber is kept at or near normal pressure for a certain length of time, there is a drawback that the distribution of membrane properties is not uniform.

[Problem to be solved by the invention]

Therefore, a thin film can only be formed under limited growth conditions, and in order to improve the uniformity of the film thickness, it is sometimes necessary to use a film with a lower quality.

That is. In conventional shrimp/CVD equipment. In order to make the film thickness distribution uniform, the lengthening conditions were varied (substrate temperature, pressure of a certain lengthening gas, flow rate, and shape of the internal jig) to find the optimum conditions.

However, changing the substrate temperature, Kaicho gas pressure, and flow rate changed the film quality itself, causing problems.

For example, when advising a highly concentrated buried layer. First, a highly concentrated diffusion region is formed on the substrate surface. When a shrimp layer is deposited on top of this, autodoping due to the movement of impurities in the gas phase varies depending on the growth conditions.

That is, when epitaxial growth is performed at a growth gas pressure of 760 Torr, the amount of impurities taken into the layer from the high concentration diffusion region becomes large, and an impurity-introduced layer is formed over the entire interface with the substrate. On the other hand, if it is carried out at 60 Torr, the amount of impurities taken in will be reduced, and as a result, a lower pressure or length will eliminate the need to form an extra impurity-introduced layer.

Among the predetermined conditions, changing the gas pressure will cause a difference in autodoping as shown in this example, changing temperature will cause a difference in autodoping and crystallinity, and if the flow rate is too high, the crystallinity will deteriorate. In this way, when the length conditions change, the film quality changes.

As mentioned above, the conventional method is to improve the film thickness distribution. There was a limit to what could be done without changing the film quality.

The object of the present invention is to obtain a device that does not impair the uniformity of film property distribution under a wide range of predetermined conditions.

[Means to solve the problem]

The solution to the above problem consists of a reaction chamber, a plurality of susceptors arranged in the reaction chamber and on which the wafers to be grown are placed, a gas introduction pipe for introducing a reaction gas into the reaction chamber, and a gas introduction pipe sandwiching the susceptor. and an exhaust pipe provided opposite to the reaction chamber and having an opening for exhausting the reaction chamber. a vapor phase growth apparatus comprising a plurality of individual exhaust pipes, each of which is arranged in parallel around the susceptor and has its opening at a different position;
Alternatively, by using a structure in which the exhaust pipe is divided into a plurality of chambers in the direction of the pipe axis and each chamber can be evacuated independently, the exhaust time or speed of the exhaust system for evacuating each chamber is adjusted so that each chamber can be evacuated from the reaction chamber. This is achieved by a vapor phase growth method that makes the exhaust volume uniform.

[Effect]

The present invention is. Exhaust air using multiple individual exhaust pipes with openings at different heights, or divide the inside of the exhaust pipe into multiple chambers in the pipe axis direction and independently adjust the exhaust speed (degree of valve opening) or exhaust time (valve opening degree). The opening time) can be adjusted.

As a result. The reaction chamber can be evacuated evenly in the vertical direction, and therefore the film thickness distribution can be improved.

〔Example〕

Figures 1 (1) and (21) are a structural diagram of an exhaust pipe and an exhaust system diagram according to an embodiment of the first invention.

Since the structural diagram of the entire device is the same as that of the conventional example, only the structural diagram of the exhaust pipe will be shown in the following embodiments.

In Figure 1 (1), each has openings at different heights. Individual exhaust pipe that exhausts air downward 4^. By exhausting 4B and 4C independently and adjusting the exhaust speed of each,
The reaction chamber can be evacuated evenly in the vertical direction.

Here, exhaust pipe 4A. 48. In 4C, the heights of the tubes are different, but they may be the same height as long as the heights of the openings are different.

Also, each individual exhaust pipe has one elongated hole as an opening. It may be replaced with multiple holes.

In Fig. 1 (2), individual exhaust pipes 4A, 4B, 4
C are collectively connected to pump Pu through valves Vn, Vg, and Vc, respectively.

Adjust the valves VA, V++, and Vc to equalize the exhaust volume from the reaction chamber to each individual exhaust pipe.

FIG. 2 is an exhaust system diagram illustrating an embodiment of the second invention.

In the figure. The exhaust pipe 4 is vertically divided into four parts by a partition wall P. It has a structure that allows each to be exhausted independently.

Each of the divided chambers 41, 42, 43 of the exhaust pipe 4. 4
4 are collectively connected to the pump Pu via valves V, , V, V, , V, respectively.

The film thickness distribution of the upper and lower wafers can be controlled by adjusting the amount of exhaust air from each chamber by adjusting the valves 4 to VD.

In this case, ■ Adjust the valves V and ~VIl to reduce the exhaust volume of each chamber in order from the upper chamber. Alternatively, (1) An air-operated valve may be used for each valve V A NV o, and the opening time may be made shorter in order from the upper chamber.

The optimal value of (2) above is determined by measuring the film thickness distribution of all wafers after actual growth.

In this example, the exhaust pipe 4 is divided into four, but it may be divided into a larger number of chambers.

next. Examples of precepts using these devices will be explained.

Parallel conditions Wafer: 8 inch φ Si wafer Number of wafers processed: 10 Film material: Si epi layer Parallel gas: SizH6+tl Pressure of a certain length gas: 4.5 Torr Flow rate of a certain length gas: Si2H6300 SCCM, Hz 15s
1M, substrate temperature: 900°C, certain length condition for certain length speed = 0.1 μm/distribution? Wafer: 8 inch φ Si wafer Number of wafers processed: 10 Film material: Si epi layer or long gas Sl 2H6 + Hz Growth gas pressure: 100 Torr Flow rate of long gas: SizH
b 100 SCCM11■ 75SlM. Substrate temperature: 900''C Length speed: 065 μm/min In all of the above growth examples, a film thickness distribution within ±3% was obtained.

〔Effect of the invention〕

As explained above, according to the present invention, it was possible to obtain a shrimp CVD apparatus that does not impair the uniformity of film property distribution under a wide range of growth conditions.

especially. It is most effective in epi-kaicho performed under normal pressure or near normal pressure.

[Brief explanation of drawings]

Figures 1 (1) and (2) are a structural diagram of an exhaust pipe and an exhaust system diagram according to an embodiment of the first invention. FIG. 2 is an exhaust system diagram illustrating an embodiment of the second invention, FIG. 3 is a schematic sectional view of a conventional shrimp/CVD apparatus, and FIG. 4 is a plan view thereof. In the figure, l is the reaction chamber and 2 is the susceptor. 3 is a gas introduction pipe, 4 is an exhaust pipe 4A to 4C are individual exhaust pipes, and 5 is a rotating shaft 11.

Claims (2)

[Claims] (1) A reaction chamber, a plurality of susceptors arranged in the reaction chamber and on which wafers to be grown are placed, a gas introduction pipe for introducing a reaction gas into the reaction chamber, and opposing positions of the gas introduction pipes with the susceptor in between. an exhaust pipe provided in the susceptor and having an opening for evacuating the reaction chamber, the exhaust pipe consisting of a plurality of individual exhaust pipes arranged in parallel around the susceptor and each having the opening at a different position. A vapor phase growth apparatus characterized by: (2) A reaction chamber, a plurality of susceptors arranged in the reaction chamber and on which wafers to be grown are placed, a gas introduction tube for introducing a reaction gas into the reaction chamber, and opposing positions of the gas introduction tubes with the susceptor in between. and an exhaust pipe that is provided in the chamber and has an opening to exhaust the reaction chamber, and the exhaust pipe is divided into a plurality of chambers in the tube axis direction, and the structure is such that each chamber can be exhausted independently. A vapor phase growth method characterized by adjusting the evacuation time or evacuation speed of the system to equalize the amount of evacuation from the reaction chamber to each chamber.