JPH0210864B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] The heat of the heater in the vapor phase growth apparatus is used to heat an inert gas, and the heated inert gas is flowed from the bottom of the substrate to change the temperature distribution of the substrate and the inside of the apparatus. Minimizes temperature changes due to pressure fluctuations.

[Industrial application field]

TECHNICAL FIELD The present invention relates to a vapor phase growth apparatus, and more specifically, to an improvement in a means for heating a substrate in the same apparatus.

[Prior Art] When forming an insulating film such as a SiO ₂ film or a silicon nitride film, a metal film such as W, Al, Ti, Mo, or a silicide film of these films on a substrate such as a silicon wafer, chemical vapor deposition ( The film is formed by a CVD (CVD) method, and an apparatus shown in cross-section in FIG. 5 is used for this purpose. In the figure, 11 is a chamber;
12 is a susceptor made of aluminum (Al) or stainless steel (SUS), 13 is a substrate such as a wafer, 14 is a gas supply section, 15 is a heater, and 16 is an exhaust pipe. It is a resistance heating type that is heated by heat. The gas supply unit 14 supplies a reactive gas in a shower shape as shown by the arrow in the figure, and a chemical vapor phase reaction occurs on the heated substrate 13, so that a predetermined film grows on the substrate 13.

In addition to the resistance heating type mentioned above, there are other types shown in Figure 6.
There is an IR heating (lamp heating) type, and in this type of device the susceptor 12a is made of quartz and the lamp 17
The substrate 13 is heated by the radiant heat of ultraviolet rays from the substrate 13.

[Problem that the invention seeks to solve]

Conventional equipment uses thermal energy through heat transfer or radiant heat at the point of contact with the substrate, so the temperature distribution depends on the distribution of the contact surface, etc., and in temperature-sensitive reactions such as vapor phase growth, the growth of the grown film There is a problem that the distribution is not constant. That is,
Thermal energy is transferred from the heater 15 to the susceptor 12
, conducts from the susceptor 12 to the substrate 13,
It is difficult to obtain uniformity in this thermal energy conduction.

Furthermore, the temperature of the substrate is highest at the center and decreases toward the periphery, where the temperature at the periphery can be as much as 10 degrees Celsius lower than at the center.

In the lamp heating type shown in FIG. 6, a film not only grows on the surface of the quartz susceptor other than the part where the substrate 13 is placed, but also gas enters between the substrate and the susceptor and the film grows. However, there is a problem in that such a film affects the transmission mode of radiant heat, resulting in poor thermal efficiency.

Additionally, during film formation, a film grows on the peripheral area shown by reference numeral 18 in FIG. 5 other than where the susceptor substrate is located, and the film peels off and falls on the substrate 13 as dust and grows. There is also the problem of deteriorating the film quality of the film.

Furthermore, in the conventional method, the substrate is heated by heating at the contact surface between the heat transfer medium in the chamber and the susceptor of the substrate, so when the pressure in the chamber decreases and the heat transfer medium decreases, the substrate temperature decreases. There is also the problem of changes in substrate temperature due to pressure fluctuations.

The present invention was created in view of these points, and it is an object of the present invention to provide an apparatus that can uniformize temperature distribution and suppress temperature changes due to changes in pressure.

[Means for solving problems]

FIG. 1 is a sectional view of an embodiment of the present invention, in which the heating means of FIG. 5 is modified, and 2
1 is a susceptor, and 22 is an inert gas heating tube.

In the present invention, the heater 15 is used to heat the inert gas (He, Ar, etc.) passing through the inert gas heating tube 22, and the heated inert gas is transferred to the substrate 1.
For this purpose, one or more pores connected to the center of the susceptor 21 are made and heated inert gas is spouted from the pores, or heated inert gas is flowed from the center onto the surface of the susceptor 21. Grooves extending radially outward are formed along which the heated inert gas flows.

[Effect]

In the above-described apparatus, the heated inert gas is uniformly flowed from below the substrate 13, so that the entire substrate is uniformly heated.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1 again, the heater 15 is the same as the conventional example, but around the heater 15
An inert gas heating tube for passing an inert gas such as He, Ar, etc. is arranged, and the inert gas is caused to flow as shown by arrow I in the figure. The inert gas is heated while passing through the inert gas heating tube 22 heated by the heater 15 .

Referring to FIG. 1, in an embodiment of the present invention,
The diameter of the substrate 13 (the length indicated by D1 in the figure) is
100 mm, the diameter of the susceptor 21 (length indicated by D2 in the figure) is 120 mm, the outer edge of the substrate 13 and the susceptor 2
The distance between the inner edge of the protrusion of the susceptor 21 and the inner edge of the protrusion shown in the figure as g1 is 5 mm, the width of the protrusion of the susceptor 21 as g2 in the figure is 5 mm, and the number of turns of the inert gas heating tube 22 is n= 10 to 100, the outer diameter of the heating tube shown as d in the figure is 1/8 inch (approximately 0.32 cm), and the distance between the upper end of the hole 23 and the bottom surface of the substrate 13, shown as h in the figure, is 5 Each was set to ~10 mm. Further, as shown in FIG. 2b, which is an enlarged cross-sectional view taken along line B-B in FIG. 2a, the depth d and width w of the groove 24b are each 5 mm.
In addition, the groove 24 at the part of the groove 24a that contacts the groove 24b
The width 〇 of a was set to 5 mm, and the width g2 of the protrusion at the outer edge of the susceptor 21 was set to 5 mm as described above.

The heated inert gas is scattered from a hole 23 provided in the center of the susceptor in all directions as shown by the arrows in the figure, uniformly heating the substrate 13 from below. One hole 23 may be provided in the center as shown in FIG. 1, or a plurality of holes 23 may be provided on average in a portion other than the center of the susceptor. In the illustrated embodiment Ar or He
Gas was supplied at a flow rate of 10-100 c.c./min.

In another embodiment of the invention, the heated inert gas is transferred to the susceptor 2 shown partially in FIG.
Grooves 24a formed radially from the center on the surface of 1
It flows along the groove 24b toward the peripheral groove 24b, and in the process rises from the groove 24a, uniformly heating the substrate 13 from below. In the illustrated example, the grooves 24a are cut at intervals of 1 to several degrees on the order of 1 mm, and are arranged so that the peripheral edge of the substrate is positioned approximately at the center of the peripheral groove 24b.

The two embodiments described above can also be applied to the lamp heating type shown in FIG. 6, and the only difference in that case is whether the heater is a resistance heating type or a lamp heating type. .

The results of measuring the substrate temperature with a radial thermometer when the substrate is heated using the device in FIG. 1 and the conventional device are shown in the diagram in FIG. C is the center of the board, E is the edge of the board, and the vertical axis shows the temperature in °C.
I got it. Solid line A is when the device of the present invention is used;
The substrate temperature averaged 300° C. at the center, edges and other parts of the substrate. Dotted line B shows the case of the conventional example, where the temperature difference T1 between the center and the edge is approximately 10
It was also warm.

FIG. 4a is a diagram showing the relationship between pressure fluctuations within the chamber and substrate temperature fluctuations, in which the horizontal axis represents time and the vertical axis represents temperature in °C. Point X on the horizontal axis
is the point where the pressure inside the chamber changed from 1 Torr to 0.1 Torr, and the reason why the pressure dropped to 0.1 Torr is because He gas started to be supplied into the chamber at a flow rate of 10 c.c./min. The solid line Y represents the case of the present invention, in which the substrate temperature was maintained at a constant temperature of 300°C even when the pressure fluctuated, whereas in the conventional example shown by the dotted line Z, the substrate temperature decreased as the pressure decreased, and the present invention There was a temperature drop of T2=20°C compared to the case of the invention.

In one embodiment of the present invention, the apparatus shown in FIG. 1 is placed in a vacuum chamber, and WF ₆ gas is supplied at 10 sccm,
Supply SiH ₄ gas at a flow rate of 5 sccm, H ₂ gas at 200 sccm, and He gas at a flow rate of 10 sccm into the vacuum chamber through a mass flow controller, and adjust the substrate temperature to 400°C and the pressure in the vacuum chamber to 0.1 to 10 Torr.
The tungsten silicide film was grown by setting the temperature within the range of . The process at that time is shown in Figure 4b, in which time t is plotted on the horizontal axis, pressure, temperature,
_H2 supply ON and OFF, WF ₆ and SiH ₄ ON and
The OFF relationships are represented by lines A, B, C, and D, respectively. By forming the film under these conditions, we were able to suppress the film pressure distribution to 5% or less, but with the conventional method, the film pressure distribution was 10%.
It was impossible to reduce the amount below. In the above process, since He was constantly supplied,
At the initial stage of the process the pressure is 0.1Torr,
At this time, the partial pressure of He matched the total pressure. Turn on the source gas (WF ₆ , SiH ₄ ) as shown by line D,
Since the switch was turned off, the pressure changed as shown by line A.

Incidentally, no film growth was observed on the edge portion 18 of the susceptor shown in FIG. 5, and the conventional problem of dust generation was solved. It was confirmed that no growth occurred and the heat transfer efficiency was not impaired.

〔Effect of the invention〕

As described above, according to the present invention, He,
Since the inert gas such as Ar serves as a uniform heat source, the substrate is kept at a constant temperature, and since the inert gas flows out from the susceptor, there is no film formation on the surface of the susceptor, which reduces dust generation and heat transfer efficiency. This prevents a decrease in the temperature of the substrate, and also prevents changes in the temperature of the substrate due to pressure fluctuations within the chamber, which is effective in improving the yield and reliability of semiconductor device manufacturing.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a partial view of the surface of a susceptor according to the present invention, in which a is a plan view, b is an enlarged sectional view taken along the line B-B in the figure a, and FIG.
FIG. 3 is a diagram showing the substrate temperature in the present invention and the conventional example, FIG. 4 a is a diagram showing the relationship between the pressure fluctuation of the device and the substrate temperature in the present invention and the conventional example, and FIG. Fig. 5 is a sectional view of a conventional example, and Fig. 6 is a sectional view of a part of the conventional example. In Figures 1, 2, 5, and 6, 1
1 is a chamber, 12 and 12a are susceptors, 13 is a substrate, 14 is a reaction gas supply section, 15 is a heater, 1
6 is an exhaust pipe, 17 is a lamp, 18 is an edge portion of a susceptor, 21 is a susceptor, 22 is an inert gas heating tube, 23 is a hole, and 24a and 24b are grooves.

Claims (1)

[Claims] 1. In an apparatus for forming a film by chemical vapor deposition on a substrate 13 heated within a chamber 11, an inert gas heating tube 22 is disposed around a heater 15, and a heated inert gas A vapor phase growth apparatus characterized in that the substrate 13 is heated by spraying active gas onto the substrate 13 on the susceptor through a hole 23 provided in the susceptor 21. 2. The device according to claim 1, wherein a plurality of the holes are formed. 3. The device according to claim 1, wherein the heater is a lamp 17. 4. The device according to claim 1, wherein grooves 24a and 24b are provided in the susceptor 21, and the heated inert gas flows through these grooves.