JP2000058527A - Rotary device and method for vapor phase growth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the embeddability in a trench. SOLUTION: A substrate 1 to be treated is set on a stage 2 in a reaction chamber 3 and the stage 2 is rotated at a prescribed rotating speed. In the middle of a reactive gas supplying pipeline 14, a control valve 15 is provided and starts and stops (or controls) the supply of a reactive gas to the reaction chamber 3. A valve controller 21 which controls the valve 15 is constituted of a storing section, valve drive control section, etc. In the storing section, a program in which the supplying pattern of the reactive gas is set is registered for intermittently supplying the reactive gas to the reaction chamber 3 (or repeatedly changing the flow rate of the gas). The valve drive control section controls the valve 15 by sending on/off (or flow rate control) signals to the valve 15 based on the program registered in the storing section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary type vapor phase growth apparatus and a vapor phase growth method using the apparatus.
The present invention relates to an apparatus and a method suitable for embedding an insulating material or the like in a trench formed on a surface of a substrate to be processed.

[0002]

2. Description of the Related Art FIG. 4 shows an outline of a rotary thermal CVD apparatus as an example of a conventional rotary vapor phase growth apparatus. This apparatus includes a reaction chamber 3, a stage 2, a heater 6, a rotary drive shaft 7, reaction gas supply pipes 14, 17, an exhaust port 20, and the like.

A stage 2 is arranged inside a reaction chamber 3, and a substrate 1 to be processed is set on the stage 2. The stage 2 is supported on the upper end of a rotary drive shaft 7, which passes through a vacuum seal 11 provided on a lower plate 13 of the reaction chamber 3, and
It is connected to the. A heater 6 is incorporated inside the stage 2, and the heater 6 is connected to a heater power supply 8 arranged outside the reaction chamber 3.

In the vicinity of the top of the reaction chamber 3, two reaction gas supply pipes 14 and 17 are connected, and these are connected to the reaction gas cylinder 1 via valves 15 and 18, respectively.
6 and 19 are connected. An exhaust port 20 for exhausting gas from the reaction chamber is connected near the bottom of the reaction chamber 3. A diffusion plate 9 having a large number of nozzle holes 10 is disposed above the stage 2 in order to uniformly supply the reaction gas to the surface of the substrate 1 to be processed. The reaction gas supply pipes 14 and 17 are connected above the diffusion plate 9. The reaction gas introduced above the diffusion plate 9 through the reaction gas supply pipes 14 and 17 is supplied to the surface of the substrate 1 through the nozzle hole 10.

According to the rotary thermal CVD apparatus as described above,
While the substrate 1 is being rotated, a reactive gas is supplied to the surface of the substrate 1 to deposit a thin film by a vapor deposition method.
By rotating the substrate 1, the gas replacement efficiency on the surface of the substrate 1 is increased, and as a result, the quality and uniformity of the thin film to be deposited are improved, and the deposition rate is further increased. It is known. This is due to the fact that even when the same flow rate of the reaction gas is flowed, the efficiency of the reaction into a thin film, that is, the reaction efficiency is remarkably improved. The number of revolutions at which such effects can be obtained depends on various factors such as the viscosity, pressure, molecular weight, and temperature of the reaction gas, the outer diameter of the rotating stage, and the amount of gas supplied.
It is preferably at least 00 rpm.

(Problems of the conventional rotary vapor phase growth apparatus)
However, when a thin film such as an interlayer insulating film is deposited on a substrate to be processed having a trench (deep groove portion) formed on a surface thereof by using a conventional rotary vapor phase growth apparatus, the trench is buried (trench). It is not easy to fill the inside with a thin film material. This is because the gas replacement rate near the bottom of the trench is much lower than the gas replacement rate near the trench entrance, and the deposition rate at the bottom of the trench is lower than the deposition rate at the trench entrance. This is due to being smaller. As a result, it is not easy to completely fill the inside of the trench with the thin film material. As a result of experiments, it has been found that good results cannot be obtained even when the aspect ratio (trench depth / trench width) is about 1.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a rotary type vapor phase growth apparatus and a method capable of improving trench filling properties. To provide.

[0008]

According to the present invention, there is provided a rotary vapor phase epitaxy apparatus comprising: a reaction chamber; a stage arranged in the reaction chamber, the stage holding a flat substrate to be processed and rotating at a predetermined rotation speed;
A reaction gas supply pipe for supplying the reaction gas into the reaction chamber, a control valve provided in the middle of the reaction gas supply pipe for supplying and stopping the reaction gas to the reaction chamber, and a valve control device for controlling the control valve. A rotary gas phase growth apparatus that supplies a reaction gas into a reaction chamber while rotating the substrate to be processed and deposits a thin film on the substrate to be processed. A storage unit for registering a program in which a supply pattern for repeatedly changing a gas supply amount at predetermined time intervals is registered, and a valve drive for controlling the control valve based on the program registered in the storage unit And a control unit.

According to the rotary vapor phase epitaxy apparatus of the present invention, the reactant gas is supplied to the surface of the substrate by repeatedly changing the supply amount at predetermined time intervals, thereby forming the surface of the substrate. By adjusting the concentration distribution of the reactant gas inside the trench, the deposition rate at the bottom of the trench can be made to approach the deposition rate at the entrance of the trench. As a result, a trench having a high aspect ratio can be relatively easily buried.

In order to supply the reaction gas intermittently, a program in which a supply time and a stop time are set is used, or a reaction with respect to time is performed such that the supply amount is repeatedly changed at predetermined time intervals. A program in which a change in the gas supply amount is set may be used.

[0011]

FIG. 1 is a schematic diagram showing an example of a rotary thermal CVD apparatus according to the present invention. In the figure, 3 is a reaction chamber, 2 is a stage, 6 is a heater, 7 is a rotary drive shaft, 20
Is an exhaust port, 14 and 17 are reaction gas supply pipes, 15
Reference numerals 18 and 18 denote a control valve, 16 denotes a monosilane gas cylinder, 19 denotes a nitrous oxide gas cylinder, 21 denotes a valve control device, 22 denotes a temperature measuring device, and 23 denotes a heater control device.

A stage 2 is disposed inside the reaction chamber 3, and a silicon wafer 1 (substrate to be processed) is placed on the stage 2.
Is held. The stage 2 is supported on the upper end of a rotary drive shaft 7, and the rotary drive shaft 7 is attached to a lower plate 13 of the reaction chamber 3.
Is connected to the rotation transmission mechanism 4 through a magnetic fluid seal unit 11 (vacuum seal) provided in the, and the rotation transmission mechanism 4 is connected to the motor 5. Inside the stage 2, a heater 6 for heating the silicon wafer 1 via the stage 2 is incorporated. The heater 6 is connected to a heater power supply 8 arranged outside the reaction chamber 3 via a wiring arranged inside the rotary drive shaft 7. Note that the rotary drive shaft 7 has a double structure, and the heater 6, the wiring, and the like incorporated therein do not rotate.

The upper portion of the reaction chamber 3 is closed by an upper plate 12 made of quartz. The lower part of the reaction chamber 3 is closed by a lower plate 13 made of stainless steel. In this example, two reaction gas supply pipes 14 and 17 are connected to the vicinity of the ceiling of the reaction chamber 3, and these are connected to a monosilane gas cylinder 1 via control valves 15 and 18, respectively.
6 and a cylinder 19 of nitrous oxide gas.
An exhaust port 20 for exhausting gas from inside the reaction chamber 3 is connected near the bottom of the reaction chamber 3. By controlling the exhaust speed of the gas from the exhaust port 20, the pressure in the reaction chamber 3 is adjusted.

A diffusion plate 9 having a large number of nozzle holes 10 is arranged above the stage 2 in order to uniformly supply the reaction gas to the surface of the silicon wafer 1. The size and arrangement of the nozzle holes 10 are optimized by simulation or the like in order to obtain a uniform gas flow. The reaction gas supply pipes 14 and 17 are connected to the upper side of the diffusion plate 9. The reaction gas introduced above the diffusion plate 9 through the reaction gas supply pipes 14 and 17 is supplied to the surface of the silicon wafer 1 through the nozzle holes 10. The above configuration is common to the conventional rotary thermal CVD apparatus (FIG. 4).

In the rotary thermal CVD apparatus according to the present invention,
A control valve 15 provided in the middle of the reaction gas supply pipe 14 is connected to a valve control device 21, and the control valve 15 is opened and closed based on a signal sent from the valve control device 21. This valve control device 2
Reference numeral 1 includes a storage unit, a valve drive control unit, and the like. In the storage unit, in order to supply the reaction gas intermittently into the reaction chamber 3, a program in which the supply time and the stop time of the reaction gas are set in advance is registered. The valve drive control unit is
On the basis of the program registered in the storage unit, o
An n / off signal is sent to the control valve 15 to control opening and closing of the control valve 15.

A radiation type temperature measuring device 22 for measuring the temperature of the silicon wafer 1 is provided above the upper plate 12.
Is installed. The temperature measuring device 22 is connected to the heater control device 23, and controls the output of the heater 6 based on the measured value of the temperature of the silicon wafer 1.

Next, an operation method of the above-mentioned rotary thermal CVD apparatus will be described. In the following, a case where a SiO ₂ thin film is formed on a silicon wafer 1 on which a trench having an aspect ratio of 1.5 is formed using a monosilane gas and a nitrous oxide gas as a reaction gas will be described as an example.

First, the silicon wafer 1 is set on the stage 2. The inside of the reaction chamber 3 is evacuated to a predetermined pressure (for example, 10 ⁻⁶ torr) through the exhaust port 20.
After the exhaust is completed, the temperature of the heater 6 is started to rise. The temperature of the silicon wafer 1 is measured by a temperature measuring device 22, and the data is sent to a heater control device 23. The heater control device 23 outputs the output of the heater power supply 8 so as to match a preset temperature rising curve. Control.

As a result, when the temperature of the silicon wafer 1 reaches a predetermined temperature, the motor 5 is driven to
Is rotated at a predetermined rotation speed. In this example, 2000r
pm. After the rotation speed of the stage 2 reaches a predetermined value,
The supply of the reaction gas is started. That is, the control valve 18 is opened to supply the nitrous oxide gas from the reaction gas supply pipe 17, and the control valve 15 is opened to supply the monosilane gas from the reaction gas supply pipe 14. At this time, control of opening and closing of the control valve 15 is performed by a signal from the valve control device 21, and the control valve 1 is opened and closed intermittently. The reason why only the control valve 15 is opened and closed intermittently is as follows.
_{2 This is because} the growth rate of the thin film greatly depends on the flow rate of the monosilane gas. However, both gases may be supplied intermittently.

FIG. 2A shows an example of a monosilane gas supply pattern (program) by opening and closing the control valve 15. This example shows a program that opens the valve for 5 seconds (t1) and then closes the valve for 5 seconds. Such a program is stored in the valve control device 21 in advance.
Fill in and register. As described above, when the monosilane gas is intermittently supplied into the reaction chamber 3, the deposition rate at the bottom of the trench is improved by the following phenomenon.

That is, when the control valve 15 is open, the monosilane gas is uniformly distributed on the silicon wafer 1. At this time, inside the trench, FIG.
As shown in (a), a region having a high concentration of monosilane gas is formed in the upper portion (entrance portion), and the concentration of the monosilane gas is low near the bottom portion. This is because the transport of gas molecules of monosilane is caused by diffusion. The vapor growth rate depends on the concentration of monosilane gas, and the higher the concentration, the higher the vapor growth rate. Therefore, in this state, the vapor phase growth proceeds at the entrance of the trench, and the vapor phase growth at the bottom of the trench becomes more difficult.

Therefore, the supply of the monosilane gas is stopped at appropriate time intervals. When the supply of the monosilane gas is stopped, if the stage 2 is not rotating, the distribution of the monosilane concentration in the trench is gradually decreased as a whole without substantially changing. On the other hand, when the stage 2 is rotating (in the apparatus of the present invention, the stage 2 is rotating), the gas flow rate above the trench is large, and thus the pressure is also small, so that the monosilane gas in the trench is above the trench. And is exhausted out of the trench. At this time, the monosilane gas near the bottom of the trench has a small conductance until it is drawn into the gas flow, so that it remains inside the trench, diffuses slowly toward the top of the trench, and is then exhausted outside the trench. . As a result, as shown in FIG. 3B, a high concentration region is formed near the bottom of the trench, and the concentration distribution is reversed between the entrance and the bottom of the trench. As a result, vapor phase growth proceeds at the bottom of the trench. After a predetermined time has elapsed, the control valve 15 is opened again,
Restart the supply of monosilane gas.

By repeating the above operation until a thin film having a predetermined thickness is deposited, the trench can be buried in a satisfactory state. In addition, regarding the relationship between the rotation speed of the stage 2 and the opening and closing time of the control valve 15,
First, the opening time of the control valve 15 is determined by the shape of the groove having the maximum aspect ratio of the silicon wafer to be processed. The closing time of the control valve 15 can be shortened as the rotation speed of the stage 2 increases. .

Incidentally, the number of rotations (200
0 rpm), the closing time of the control valve 15 is set to 5
It was found that the effect was obtained when the time was longer than sec. The opening time was set to 5 seconds in the above example. Above that, it was found that the amount of deposition during one opening time became too large, and the trench was not buried properly.

FIG. 2B shows another example of the supply pattern (program) of the monosilane gas. By optimizing the change in gas concentration in the trench by repeatedly changing the flow rate at a predetermined time interval in this manner, a trench with a large aspect ratio can be effectively filled in a shorter time.

The rotary vapor phase growth apparatus according to the present invention is not limited to the configuration shown in the above example.
For example, in the above example, a magnetic fluid seal unit is used as the vacuum seal 11, but a unit such as a magnetic bearing may be used. Further, in the above example, two reaction gas supply pipes of the monosilane gas system and the nitrous oxide gas system are used. However, outside the reaction chamber, the supply pipes are integrated into one by using a mixing unit. Is also good. However, one control valve is required for each gas.

[0027]

According to the rotary vapor phase epitaxy apparatus of the present invention,
By rotating the substrate to be processed, uniformity of the quality and thickness of the vapor-grown thin film and high gas efficiency are maintained, and at the same time, trenches having an aspect ratio of 1.5 or more can be filled.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a rotary thermal CVD apparatus according to the present invention.

FIG. 2 is a diagram showing an example of a supply pattern (program) of a reactive gas in a rotary thermal CVD apparatus according to the present invention;
(A) shows an example in which the reaction gas is intermittently supplied, and (b)
Represents an example in which the supply amount of the reaction gas is changed.

FIG. 3 is a diagram illustrating an effect of intermittently supplying a reaction gas in a rotary thermal CVD apparatus according to the present invention;
(A) shows a state where the reaction gas is being supplied, and (b) shows a state where the supply of the reaction gas is stopped.

FIG. 4 is a schematic configuration diagram showing an example of a conventional rotary thermal CVD apparatus.

[Description of Signs] 1 ... silicon wafer (substrate to be processed), 2 ... stage, 3 ... reaction chamber, 4 ... rotation transmission mechanism, 5 ... motor, 6 ... heater, 7: rotary drive shaft, 8: heater power supply, 9: diffusion plate, 10: nozzle hole, 11: magnetic fluid seal unit (vacuum seal), 12: upper plate, 13 ... lower plate, 14 ... reaction gas supply pipe, 15 ... control valve, 16 ... cylinder (monosilane gas), 17 ... reaction gas supply pipe, 18 ... control valve, 19 ... -Cylinder (nitrous oxide gas), 20: exhaust port, 21: valve control device, 22: temperature measuring device, 23: heater control device.

Claims (6)

[Claims] A reaction chamber; a stage disposed in the reaction chamber, the stage holding a flat substrate to be processed and rotating at a predetermined rotation speed; a reaction gas supply pipe for supplying a reaction gas into the reaction chamber; A control valve provided in the middle of the gas supply pipe to supply and stop the reaction gas into the reaction chamber; and a valve control device controlling the control valve, wherein the reaction gas is supplied into the reaction chamber while rotating the substrate to be processed. A rotary gas phase epitaxy apparatus for depositing a thin film on the substrate to be processed, wherein the valve control device comprises: a supply pattern for repeatedly changing a supply amount of the reaction gas into the reaction chamber at predetermined intervals. A storage unit for registering a program in which is set, and a valve drive control for controlling the control valve based on the program registered in the storage unit. If, rotary vapor deposition apparatus characterized by comprising a. 2. The program according to claim 1, wherein a supply time and a stop time corresponding to a supply pattern for supplying a reaction gas at a predetermined flow rate intermittently at predetermined time intervals are set. Item 4. A rotary vapor phase growth apparatus according to item 1. 3. The program according to claim 1, wherein the program sets a time corresponding to a supply pattern in which the supply amount of the reaction gas is repeatedly changed at predetermined time intervals, and a change in the supply amount of the reaction gas with respect to this time. The rotary vapor phase epitaxy apparatus according to claim 1. 4. In a vapor phase growth method for accommodating a flat substrate to be processed in a reaction chamber and supplying a reaction gas into the reaction chamber while rotating the substrate to be processed, thereby depositing a thin film on the substrate to be processed. A gas phase growth method, wherein a supply amount of the reaction gas into the reaction chamber is repeatedly changed at predetermined time intervals. 5. Use of a valve control device for automatically controlling the supply and stop of the reaction gas into the reaction chamber and the intermittent supply of the reaction gas. A program in which a stop time is set is registered in advance, and when depositing a thin film on a substrate to be processed by a vapor phase growth method, the supply and the stop of the reaction gas are automatically controlled based on the program. The vapor phase growth method according to claim 4, wherein 6. A valve control device for automatically controlling a supply amount of a reaction gas to the reaction chamber, and a valve control device for controlling the supply amount of the reaction gas repeatedly at predetermined time intervals. A program in which a change in the supply amount of the reaction gas is set is registered in advance, and when depositing a thin film on the substrate to be processed by the vapor phase growth method, the supply amount of the reaction gas is automatically controlled based on the program. The method of claim 4, wherein: