JPH0445522A - Vapor growth device - Google Patents

Abstract

PURPOSE:To simultaneously obtain excellent uniformity in both film thickness and resistivity by setting the gas flowing line from the first nozzle pipe and gas flowing line from the second nozzle pipe in different planes against the surface of a wafer. CONSTITUTION:Nozzle pipes for supplying reactive gases are constituted principally of the first nozzle pipe 6a for supplying a reactive gas containing a silane- based reactive gas related to film growth and the second gas pipe 6b for supplying a reactive gas mainly containing an N- or P-type doping gas. The gas blowing port of the first nozzle pipe 6a is opened at a height l/3L in the length direction of the nozzle, with the L being the interval between two adjacent wafers. The gas blowing port of the second nozzle pipe 6b is opened at a height 2/3L. Therefore, such excellent values as +3% and +5% can be obtained for the film thickness uniformity and resistivity uniformity, respectively.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a vapor phase growth apparatus, particularly for in-5
The present invention relates to a vapor phase growth apparatus that forms a thin film by doping type or N type impurities.

[Conventional technology]

Although a vapor phase growth apparatus is used for various film formations, silicon epitaxial growth will be explained below.

Epitaxial growth technology has already become an important technical field in semiconductor manufacturing processes, and has become an essential process for device manufacturing, especially for bipolar devices. Furthermore, in recent years, the demand for ultra-high integration and ultra-high speed devices has led to the development of SRAMs with low power consumption and high speed Bi-0MO3 structures, and DRAMs using shrimp structures to prevent latch-up due to ultra-high integration. Although vigorously pursued, all of these devices require an epitaxial growth process.

In order to reduce the manufacturing process cost per device chip, advances are being made to increase the diameter of silicon wafers and increase the throughput of manufacturing equipment by increasing the number of wafers processed per batch. Even in epitaxial growth equipment, conventional barrel-type and pancake-type equipment
It has already become difficult to meet current requirements in terms of throughput, and recently various new types of equipment have been prototyped6.For example, hot wall using a vertical reaction tube An apparatus capable of processing a large number of large-diameter 6-inch wafers using this method has been proposed (Japanese Unexamined Patent Application Publication No. 63
-0086424).

FIG. 4 shows an outline of this device.

The apparatus shown in FIG.
The wafers 5 are held so as to be stacked horizontally and heated to approximately 900°C to 1200°C under reduced pressure in a resistance heating furnace 9, and the surface of the wafers 5 is doped with silane-based gas such as dichlorosilane (SiH2Cl2), hydrogen (H2), and doping. Epitaxial growth was performed by introducing gas.

The reaction vessel has a double structure with an inner and outer tube 2.3 supported on a pedestal 1. The outer tube 2 maintains a vacuum, and the reaction gas is supplied to the rotating wafer 5 using a nozzle tube 6. tube 3
The gas is discharged from an exhaust port 8 through a large number of gas discharge holes 7 provided in the cylindrical surface of the cylinder. With conventional equipment, PH3,82H
a, 5i related to doping gas such as AsHl and growth
Reactive gases such as H2C1, etc. are discharged from the same nozzle pipe, or doping gas and reaction gases involved in growth are discharged from different nozzle pipes, but even in the latter device, the streamlines of doping gas and the reaction gases involved in film growth are discharged. The streamlines of the reactant gas and the wafer surface were in a parallel relationship.

[Problem to be solved by the invention]

In order to uniformly grow a film on a wafer surface using a vapor phase growth method, it is necessary to uniformly supply various reactive species generated by thermal decomposition of a reactive gas to the entire region to be grown. 5LH4C
l* To explain the N-type silicon epitaxial growth of the H2PHs system as an example, S I Hx C12 is involved in film growth caused by thermal decomposition, and P generated by doping is generated by thermal decomposition of PHs.
It is necessary to uniformly supply a reactive gas species such as HI (i=1°2.3) to the entire wafer growth area. In the conventional device using the single nozzle tube mentioned above,
As shown in (B), in order to achieve uniform growth, the flow velocity of the gas ejected from the nozzle pipe 6 and the direction of the gas flow line 10 are optimized. Since there is a difference in the chemical reaction rate between the decomposed species and the St substrate, it is difficult to find growth conditions that make the film thickness and resistivity uniform at the same time.

On the other hand, a growth device using multiple nozzle tubes is shown in Figure 6 (^)
, (B), (C), (0), 5
By separately providing the nozzle pipe 6b for supplying fH2CIt to perform film growth and the nozzle pipe 6a for supplying PH and performing resistivity control, optimal conditions for film growth and resistivity can be established independently. This is what I was trying to get. However, even in the case of this device, since the gas ejection holes 6c and 6d of each nozzle pipe 6a and 6b are opened at the same height position with respect to the wafer surface, the reaction gas ejected from the gas ejection holes 6c and 6cf is particularly Because the carrier gases interfere with each other within the wafer plane, it is not possible to control the film thickness distribution and resistivity distribution completely independently. The flow pattern at the nozzle will be greatly affected by the gas flow from the other nozzle pipe.As mentioned above, conventional equipment has good film thickness uniformity and low efficiency uniformity for large diameter wafers. It has become difficult to find growth conditions that simultaneously satisfy the following.

An object of the present invention is to provide a vapor phase growth apparatus that eliminates the conventional problems by preventing mutual interference between gases within the wafer plane.

[Means to solve the problem]

In order to achieve the above object, a vapor phase growth apparatus according to the present invention includes a wafer holder and a nozzle tube, and the wafer holder stacks a plurality of wafers vertically at a constant pitch. The nozzle pipe supplies a reactive gas to the growth surface of the wafer held at each stage of the wafer holder, and mainly supplies a reactive gas containing a silane-based reactive gas involved in film growth. It is composed of a first nozzle pipe and a second nozzle pipe that supplies a reaction gas mainly containing an N-type or P-type doping gas, and a gas flow line from the first nozzle pipe and a gas flow line from the second nozzle pipe. The gas streamlines are set on different planes with respect to the wafer surface.

Further, in the present invention, the first nozzle pipe and the second nozzle pipe have gas ejection holes for the reaction gas opened at different height positions with respect to the wafer surface, and the first nozzle pipe and the second nozzle pipe The second nozzle pipes each have gas ejection holes for the reactive gas opened at different angles with respect to the wafer surface.

[Effect]

In the conventional apparatus, each gas flow line from the nozzle tube overlaps on the same plane parallel to the wafer surface, whereas in the present invention, each gas stream flows on a different plane. Therefore, mutual interference between the gas flows ejected from each nozzle pipe is significantly reduced, and good film thickness uniformity and resistivity uniformity can be obtained at the same time.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

(Example 1) Figures 1 (^), (B), and (C) are diagrams showing Example 1 of the present invention. In Figure 0, the reaction tube used for growth was the conventional apparatus shown in Figure 4. Similarly, outer tube 2 and inner tube 3
It is the same as the conventional apparatus in that it is equipped with a wafer holder 4 for holding the wafer 5 and a resistance heating furnace 9 for heating the inside of the reaction tube. In the present invention, the nozzle pipe 6 for supplying the reaction gas is mainly a silane-based gas (
The first nozzle pipe 6a supplies a reaction gas containing a reaction gas of PHs), and the second nozzle pipe 6b supplies a reaction gas mainly containing an N-type or P-type doping gas. In order to realize a characteristic gas flow pattern according to the present invention, gas ejection holes 6c are opened in the first nozzle pipe 6a at a height of 1/3L in the longitudinal direction of the nozzle pipe at intervals of adjacent wafers, and Regarding the pipe 6b, a gas ejection hole 6d is installed at a height of 2/3L.

Fifty P-type silicon wafers 5 with a diameter of 150 cm were mounted on a wafer holder 4, and the temperature inside the reaction tube was set at 1080° C. and the degree of vacuum was set at 80 torr. The wafer holder 4 is rotated at a speed of 5 revolutions per minute, and from the gas ejection hole 6C of the first nozzle pipe 6a, H, 201/sin, P Hj50011
/Sin, 201 /sin of H2 from the gas ejection hole 6d of the second nozzle pipe 6b, S i H2Cl
2 was supplied for 15 minutes at a flow rate of 200 mJ/Sin to grow an N-type silicon epitaxial film.

Figure 2 shows the measured film thickness and resistivity of the grown wafer, both of which were measured using conventional equipment (
(Fig. 5.6), the film thickness uniformity is ±
Obtain good values of 3% and resistivity uniformity of ±5%.

In this example, two nozzle pipes 6a and 6b were used, but we also attempted to grow a plurality of first nozzle pipes 6a and second nozzle pipes 6b, and good results were obtained in this case as well. There is.

(Example 2) Figures 3 (^), (B), and (C) are diagrams showing Example 2 of the present invention. In this example, the same equipment as in Example 1 was used for the reaction tube. In order to realize a characteristic gas flow pattern in this embodiment, the opening direction of the gas ejection hole 6c of the first nozzle pipe 6a is set at 60 degrees with respect to the horizontal direction on the a-a' line cross section perpendicular to the wafer surface. The opening direction of the gas ejection hole 6d of the second nozzle pipe 6b was perpendicular to the wafer surface and 30'' with respect to the horizontal direction on the -b' line cross section.

In this example, growth was performed under the same conditions as in Example 1, and the film thickness distribution and resistivity distribution were measured. As in Example 1, film thickness uniformity was ±3%, resistance was Rate uniformity ±
A good result of 5% was obtained.

〔Effect of the invention〕

As explained above, the present invention has the advantage that it is possible to form a film with uniform thickness and resistivity on large diameter wafers since it prevents mutual interference of the reaction gases from the two systems on the wafer surface.

[Brief explanation of the drawing]

FIG. 1 (A) is a cross-sectional view showing Example 1 of the present invention, (B
) is a sectional view taken along the line a-a′ in FIG. 1(A), (C) is a sectional view taken along the bb” line in FIG. 1(A), and FIG. FIG. 3(^) is a cross-sectional view showing Embodiment 2 of the present invention, and (B) is a-a'' of FIG. 3(^)
Line sectional view, (C) is bb' line sectional view of Figure 3 (^),
FIG. 4 is a longitudinal sectional view showing the reaction tube used in the present invention and the conventional apparatus, and FIG. 5 (^). (B) is a diagram showing the gas flow pattern and film uniformity of a conventional device using a single nozzle tube, and FIG. 6 (A). (B) is a diagram showing the gas flow pattern and film uniformity of a conventional device using multiple nozzle tubes, Figure 6 (C) is a cross-sectional view taken along line a-a' of Figure 6 (8), (D) is shown in Figure 6 (B
) is a sectional view taken along line bb'. 1... Frame 2... Outer tube 3... Inner tube 4... Wafer holder 5... Wafer 6.6a, 6b... Nozzle pipe 7... Gas exhaust hole 8... Exhaust Part 9: Resistance heating furnace patent applicant NEC Co., Ltd. Agent Patent attorney Nakaho Kanno ■ Figure ■ Figure Measurement position Figure (B) (C) Figure 4 Knee-eight holder Figure diagram

Claims (3)

[Claims] (1) A vapor phase growth apparatus having a wafer holder and a nozzle tube, in which the wafer holder holds a plurality of wafers stacked vertically at a constant pitch, and the nozzle tube is a device for holding a plurality of wafers stacked vertically at a constant pitch. A first nozzle pipe that supplies a reactive gas to the growth surface of a wafer held on a stage, which mainly includes a silane-based reactive gas involved in film growth, and a doping gas that is mainly an N-type or P-type doping gas. and a second nozzle pipe that supplies a reaction gas containing the gas, and the gas flow line from the first nozzle pipe and the gas flow line from the second nozzle pipe are arranged on different planes with respect to the wafer surface. A vapor phase growth apparatus characterized by the following settings. (2) The first nozzle pipe and the second nozzle pipe have gas ejection holes for the reactive gas opened at different height positions relative to the wafer surface.
) The vapor phase growth apparatus described in section 2. (3) The first nozzle pipe and the second nozzle pipe have gas ejection holes for reactant gas opened at different angles with respect to the wafer surface. Vapor phase growth equipment.