JPS5944819A - Equipment for vapor growth - Google Patents

Abstract

PURPOSE:To increase a processing capacity by a method wherein a plurality of heating coils are provided concentrically beneath a heating block and temperature control of those heating coils of inside, intermediate and outside portions is performed independently in accordance with the temperature of the heating block. CONSTITUTION:To the center of a heating block 11 a reactive gas supplying tube inserting hole 12 is provided. Heating coil group 13 is composed of an inside circumference coil 13a which is provided beneath the center portion of the block 11, an intermediate coil 13b which is positioned at the intermediate portion of the concentric coil group 13 and an outside circumference coil 13c which is positioned around the intermediate coil 13b. Each coil is electrically independent and is connected to the corresponding high frequency electric source 15a, 15b, 15c. Temperature sensors 16a, 16b, 16c are provided between the block 11 and each coil. The temperature sensors are connected to a temperature controller 17 and a calculator 18 gives a signal to the electric source group 15 according to a signal given by the temperature sensors.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a vapor phase growth apparatus.

[Technical background of the invention]

Conventionally, in order to form a desired thin film on the surface of an object to be processed such as a semiconductor wafer, an exhaust duct 3 is formed at the bottom of the air as shown in FIG.

A substantially disc-shaped heating base 4 made of carbon or the like is inserted into the upper part of the reaction gas supply pipe 2 .

The object to be processed 5 is placed on the heating base 4 .

A spiral heating coil 6 is installed below the heating base 4, as shown in FIG.

After heating the object to be processed 5 to a predetermined temperature using the heating coil 6 via the heating base 4, a thin film is formed on the surface of the object to be processed 5 by vapor phase growth. It has become. For example, when forming a thin film on the surface of the object to be processed 5 using the epitaxial growth method, when the reaction gas is 5tcz, about 1200
℃.

Approximately 1150℃, 5IH2C when S + HCZ s
12: approx. 1100℃ # SiH4: approx. 10
Heat to 50°C. Further, the frequency of the heating coil 6 shown in FIG. 2 is set in the range of 50 to 200 kHz.

A high frequency oscillator of about 200 kW is used, and the heating base 4 is usually about 600 mm in diameter and about 5 mm thick.

However, in the conventional vapor phase growth apparatus #1o, as shown in FIG. 3, when the distance L1 between the heating coil 6 and the heating base 4 is uniform, the outer circumference of the heating base 4 is ,
Since the end portion 1 has a large amount of heat dissipation, the temperature is lower than that of other regions. As a result, the object to be processed 5 on the heating base 4 could not be heated at a constant temperature, and there was a problem that slippage occurred within the object to be processed 5. In order to solve this problem, as shown in FIG.
Keep the heating coil 6'a on the outer periphery away from the heating base 4.
A vapor phase growth device has been developed in which the brass is placed close to the bottom surface of the metal. In such a vapor phase growth apparatus, the heating coil 6
' and the lower surface of the heating base 4 is set to the optimum value through trial and error according to the temperature and flow rate of the reaction gas ejected from the reaction gas supply pipe 2, vapor phase growth processing is performed. During the period, the heating base 4 can be soaked to a predetermined processing temperature for 1 minute. However, heating coil 6'
Since the distance between the heating base 4 and the lower surface of the heating base 4 is different between the center and the outer circumference of the heating coil 6', the induction given to the heating base 4 by the heating coil 6' is The amount of energy is greater at the outer circumference near the heating base 4 than at the center of the heating base 4. the result,
The temperature distribution inside the heating base 4 and the object to be processed 5 placed thereon greatly collapses before and after the vapor growth process. For this reason, there still remains the problem that slips are likely to occur within the object to be processed 5.

In order to completely eliminate this problem, the usual method is to change the set temperature in the heating base 4 during the vapor phase growth process to some extent by changing the soaking temperature 2 to suppress the thermal stress that occurs during the cooling step 1. A method inconsistent with the heat soaking method is adopted. However, with the means of breaking this uniform heating to some extent, there are variations in the distribution of the processing temperature for the aeration process, so there may be variations in the thickness of the thin film formed on the object to be processed 5, variations in the resistance value, scooking faults, bits, etc. Characteristics related to crystal defects, etc. deteriorate. Furthermore, with the recent increase in the size of semiconductor devices, the diameter of the heating base 4 has also increased to 600mmφ and 750mmφ.

As a result, heating carp 6,6' also has 200 kW and 300 kW.
1ttl, which is larger in size (more than kW) and is subject to strict regulations under the Radio Law.
I am subject to a limit. In addition, because large amounts of power are required, insulation measures and measures against radio wave leakage in equipment design are often ignored.

Also, as shown in Fig. 5, it is possible to consider a method in which the spacing L21U3 of each heating coil 6 is made sparse at the entire center and dense at the outer and inner circumferences, or the spacing L21U3 of each heating coil 6 is made denser at the outer and inner circumferences, or the spacing L21U3 of each heating coil 6 is made denser with extremely high precision. There is a need.

Moreover, it has the disadvantage that it is difficult to match it with an oscillator specific to high-frequency heating. Furthermore, as described above, there is a problem in that the temperature distribution within the heating base 4 and the object to be processed 5 is distorted during the temperature raising and lowering process before and after the vapor phase growth process.

[Purpose of the invention]

An object of the present invention is to provide a vapor phase growth apparatus that prevents the generation of spuds on objects to be processed, has high power efficiency, and has a high number of processing customers. be.

[Summary of the invention]

The present invention performs a heating operation using a plurality of heating coils arranged concentrically below a heating base in accordance with the temperature of the heating base.
By independently controlling the temperature of the intermediate section and the coils surrounding the inner and outer circumferential sections, high power efficiency and processing capacity 'M' can be achieved.
This is a vapor phase growth apparatus that can heat the object to be processed while preventing the occurrence of slip.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 6 is an explanatory diagram showing a schematic configuration of an embodiment of the present invention. In the figure, reference numeral 11 indicates a cross section of a substantially disk-shaped heating base cut along the diameter.

An insertion hole 12 into which a reaction gas supply pipe (not shown) is inserted is pressed into the center of the heating base 1. A substantially annular high-frequency heating coil 13 (hereinafter simply referred to as a heating coil) is provided below the heating base 1 . The heating coil 13 includes an inner circumferential coil 13a installed below the central portion of the heating base 1, an intermediate coil 13b located at a concentrically intermediate portion of the heating coil 13, and an outer circumference thereof. The outer peripheral coil 13c is wound. A JWi manhole 14 into which a reaction gas supply pipe is inserted is formed in the central portion of the inner peripheral coil 13a. Inner circumference coil 13m, intermediate coil 13b, and outer circumference coil 13c
IrJ', , are electrically independent and connected to the respective high frequency power supply units "15a...15c".

The inner circumferential portion may be coiled, or annular coils may be arranged concentrically. In short, the inner circumferential coil 13az, the intermediate coil 13b1, and the outer circumferential coil 1.9c are electrically independent and exist from the center to the outer circumference in the -T direction of the heating base 1. 7 is good. Inner peripheral coil 13
d and the heating base 11, between the intermediate coil 13b and the heating base 1
1, and Kid between the outer peripheral coil 13c and the heating base 11,
Temperature sensors 16a, . . . , 16c are provided to measure the temperature at the center, middle, and outer circumference of the heating base 1. The temperature sensors 16a...16c are connected to a temperature controller 17, and the temperature signal is amplified by the temperature controller 17. Temperature sensor 16
a...16c, ``5, for example, infrared absorption I
A light receiving diode made of silicon and having a length of 0.9 μnl is used. In fact, the temperature sensors 16a, . . . 16c may be installed between the coils forming the heating coil. In order to improve temperature detection accuracy, a sensing body made of a lens optical fiber is installed south of the heating base 1, and this sensing body is equipped with the aforementioned light receiving diode. UCt is fine for installation. Furthermore, '0' is placed directly above the heating base 1.
A degree sensor 16a -16c (17 installed!ijt.

It's okay. The temperature controller Noah is a No. 48 computing unit I8 that amplifies the temperature of each temperature sensor 16a...16c.
and the high frequency power supply units 15g...15c. The computing unit 18 includes temperature sensors 16a...1
Based on the temperature signal of the heating base 11 obtained from 6c, [7]
What is the optimal heating current for heating a predetermined area of the heating base 1)? From the high frequency power supply section 15a...15c to the heating coil 13
Arithmetic processing is performed and predetermined output signals are supplied to the high frequency power supply sections 15a...15c so as to be supplied to the coils of each section. In this way, the heating base 11 and the heating oil 13 are arranged so that the reaction gas supply pipe is placed inside the heating base 11 and the heating oil pipe 13, which contains the reaction gas supply pipe, the exhaust duct, etc. It is installed so as to be inserted into the insertion holes 12 and 14 of the coil 13.

According to the vapor phase growth apparatus configured in this way,
The object to be processed is placed on the heating base 1, and the atmospheric gas in the container is exhausted from the exhaust duct to maintain a predetermined pressure. Next, a reaction gas such as 5tcz is supplied into the container from the reaction gas supply pipe. Next, the temperature controller 17
and the high frequency power supply section 15a...15 by the arithmetic unit 18.
Heating π1.c supplies lJj to the heating coil 13. Flow f:
The entire area of the heating base 11 is heated from room temperature to 1, for example.
The temperature is raised at a constant heating rate to a vapor phase growth treatment temperature of 200° C., as shown by the straight line ( ] in FIG. 7. Next, during the vapor phase growth process, the temperature sensors 16a...16c,
The temperature controller 17 and the generator 18 control the heating current supplied to the heating coils from the high frequency power supply units 15a...15c, and as shown by the straight line (II) in FIG. Maintain at vapor phase growth processing temperature. Furthermore, when the temperature is lowered, the temperature of the heating base 11 is lowered at a constant temperature lowering rate as shown by the straight line OI in FIG. , including the period of temperature rise and fall before and after that, it is possible to suppress variations in the temperature If of the object to be processed placed on the heating base 11 and the grooves to an extremely small level. As shown by curves (1') and (Il+',) in FIG. 8, it was confirmed that the curves were extremely small.

Here, Tc1lJ', temperature at the center of the object to be processed, Te
is the temperature of the peripheral part of the object to be processed, TII, heating base 11
temperature. In order to compare this, a similar experiment was conducted using a conventional vapor phase growth apparatus as shown in FIG. 1, and as shown by curves (IV) and (V) in FIG. It was confirmed that the temperature variation during the period of temperature rise and fall was very large. In addition, in the vapor phase growth apparatus of the example, the difference (1"
lll') is almost zero, and no sudden changes occur within the body to be treated. As a result, it is possible to prevent slip from occurring during the vapor phase growth process. Incidentally, when the occurrence of slip in the object to be processed having a diameter of 4 inches was investigated, it was confirmed that there was no occurrence of slip in the vapor phase growth equipment of the example.

In contrast, in the conventional vapor phase growth apparatus shown in FIG. 1, it was confirmed that slip occurred in 15% of the area of the object to be processed 5. Moreover, the power efficiency at that time was 0.60 to 0.65 in the vapor phase growth apparatus of the example, and 0.50 to 0.060 in the conventional vapor growth apparatus. From this, in the vapor phase growth apparatus of the example, electric power can be effectively utilized.

In the embodiment, the heating coil 13 is divided into three parts, but as shown in FIG. The heating coil may be essentially an integral coil, and the heating coil may be divided into two parts: an intermediate coil 13b' and surrounding coils (a central coil and an outer coil) surrounding this from both sides. Here, the number of temperature sensors 168' etc. is set according to the division of the heating coil 13. Of course, J').

In addition, in FIG. 9, the same parts as in the embodiment are given the same reference numerals.

〔Effect of the invention〕

As explained above, the vapor phase growth apparatus according to the present invention has high power efficiency, large processing capacity, and
It is possible to completely prevent slippage from occurring on the object to be processed.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional vapor phase growth apparatus, Fig. 2 is an enlarged perspective view of a heating coil provided in the same apparatus, and Figs. 3 to 5 are a cross-sectional view of a conventional vapor phase growth apparatus. An explanatory diagram showing the heating coil used; FIG. 6 is an explanatory diagram showing a schematic configuration of an embodiment of the present invention; FIG. 7 is a characteristic diagram showing the relationship between the temperature of the heating base and the heating time; FIG. 8-1 is a characteristic diagram showing the relationship between the temperature inside the object to be processed and the temperature rise/fall period. FIG. 9 is an explanatory diagram showing the schematic structure of another embodiment of the present invention. 1 No. Heating base, 12 Insertion hole, 13 Heating coil, 13a Inner circumference coil, 13b Intermediate coil, 13C Outer circumference coil, 14. ...Insertion hole, 15a + 15b + 15c...
High frequency power supply section, 115 a + J 6 b + 16
c...Temperature sensor, 17...Temperature controller,
18...Performance 1'4. vessel. Applicant's Representative Patent Attorney Takeshi Suzue Examination Figure 1 0 Figure 3 Figure 4 Figure 5/. Figure 6 Figure 7 Power O processing time

Claims (1)

[Claims] A heating base rotatably provided in a depressurized container having an exhaust duct and a reaction gas supply pipe, a plurality of heating coils provided concentrically below the base, and a space between the heating coil and the base. a temperature sensor provided in the base, a temperature controller to which the temperature signal of the base is supplied from the temperature sensor and which supplies a predetermined output signal to the arithmetic unit; A heating signal is supplied from the heating coil, and the heating coil is provided with a power supply section that outputs heating currents corresponding to the central coil and surrounding peripheral coils independently of each other. Phase growth device.