JPH0513348A - Device for manufacturing semiconductor - Google Patents

Abstract

PURPOSE:To reduce dust in a reacting room and reduce defects of a semiconductor device to be manufactured by repeating pressure reduction and pressure increase in the reacting room after a processing sequence before the start of the subsequent processing sequence. CONSTITUTION:A semiconductor wafer 1 is dismounted from a boat 2 and a boat loader 4 is made to ascend to seal a reacting room 3 after a processing sequence is completed. All the valves 6 of gas to be supplied into the reacting room 3 are closed, a valve 8 for vacuuming is opened and the reacting room 3 is vacuumed by a vacuum pump. Under such a condition, after one minute, for example, the valves 6 for supplying inactive gas are opened and the pressure in the reacting room 3 is increased. At that time a large quantity of gas of 1l or more is supplied per minute so as to permit the dust adhered on the reacting room 3 to soar up in the reacting room 3 and the pressure is rapidly changed. Thus, the dust in the reacting room is removed repeatedly and a semiconductor device with less defects is manufactured without deteriorating the operability of the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and more particularly to an improved control system for a low pressure vapor phase growth apparatus.

[0002]

2. Description of the Related Art FIG.
FIG. 2 is a schematic configuration diagram showing a configuration of a CVD device),
In the figure, reference numeral 1 is a semiconductor wafer, 2 is a plurality of semiconductor wafers 1 supported, for example, a boat made of quartz, 3 is a reaction chamber for accommodating the boat 2, and 4 is the reaction chamber in which the boat 2 is mounted. A boat loader for loading and unloading into and from the chamber 3, 5 a heater surrounding the outside of the reaction chamber 3, 6 an on-off valve for supplying / stopping the gas supplied to the reaction chamber 3, and 7 supplying to the reaction chamber 3. A flow rate adjusting valve for adjusting the gas flow rate, 8 is an opening / closing valve for exhausting / stopping the vacuum exhaust of the reaction chamber 3, and 9 is the reaction chamber 3 for adjusting the vacuum exhaust capacity.
An exhaust control valve 10 for adjusting the internal pressure is a vacuum pump for performing vacuum exhaust. Further, 11b is a temperature control unit that controls the heater 5, 11c is a pressure control unit that controls the opening / closing valve 8, the exhaust control valve 9 and the vacuum pump 10, 11d is a mechanical control unit that controls the boat loader 4, and 11e is an opening / closing valve. 6, a gas control unit for controlling 6 and the flow control valve 7, 11a is a sequence control unit for controlling the temperature control unit 11b, the pressure control unit 11c, the machine control unit 11d and the gas control unit 11e. The LP-CVD apparatus defines the state of each part (temperature, pressure, machine operation, gas flow rate) for each step, and operates by sequentially changing this.

FIG. 4 is a diagram showing a state of sequential control of a conventional semiconductor manufacturing apparatus.
Reference numerals 4a and 14b are processing sequences, and reference numeral 15 is a standby state that defines the apparatus state when the processing sequences 14a and 14b are not present. White circles in the figure indicate one step, and arrows indicate transition to the next step.

Next, the operation will be described with reference to FIGS. In the conventional LP-CVD apparatus, as shown in FIG.
When the sequence 14a and 14b for the film forming process is not performed, the device state includes temperature, pressure, machine operation,
The standby state 15 in which the gas flow rate is statically defined is taken. In the standby state 15, for example, the temperature is the same as the film forming temperature (500 ° C. to 900 ° C.), the pressure is normal pressure without exhaust, and the boat loader 4 is stopped when the boat 2 is pulled out from the reaction chamber 3. The gas supplies an inert gas such as nitrogen.

In the processing sequences 14a and 14b, for example, the semiconductor wafer 1 is placed on the boat 2, the boat 2 is housed in the reaction chamber 3 by the boat loader 4, and the reaction chamber 3 is evacuated by the vacuum pump 10. Next, the semiconductor wafer 1 is heated by the heater 5 to a temperature (500 ° C. to 900 ° C.) suitable for film formation, and after the temperature of the semiconductor wafer 1 becomes uniform, a film is formed on the surface of the semiconductor wafer 1. As a material gas at the time of film formation, for example, silane is supplied when depositing a polycrystalline silicon film. At this time, the gas flow rate is controlled by the flow rate control valve 7, and the pressure in the reaction chamber 3 is a pressure suitable for film formation, for example, 10
The exhaust control valve 9 controls the pressure to be 0 Pa. After the film having the desired thickness is formed, the supply of the material gas is stopped,
The reaction chamber 3 is evacuated to remove the material gas remaining in the reaction chamber 3 and the gas generated by the chemical reaction. Next, the vacuum exhaust is stopped and an inert gas, for example, nitrogen gas, is added to the reaction chamber 3
And the pressure in the reaction chamber 3 becomes normal pressure, the boat 2
Is taken out of the reaction chamber 3 by the boat loader 4, and the semiconductor wafer 1 on which the film formation is completed is unloaded from the boat 2.

When such a processing sequence is repeated, a film is deposited inside the reaction chamber 3 in the course of the film forming reaction, but the reaction is not sufficiently performed in the portion where the heating by the heater is not sufficient, and the film is easily peeled off. A film that would be lost or a powdery substance was deposited. These become dust,
By adhering to the surface of the semiconductor wafer 1 during processing,
This causes a defect in a semiconductor device manufactured by this LP-CVD device.

[0007]

Since the conventional semiconductor manufacturing apparatus is configured as described above, in order to reduce the amount of dust adhering to the semiconductor wafer on the semiconductor wafer, pressure change due to vacuum exhaust or gas introduction. As a result, there is a problem that the processing time becomes long, and the number of times of disassembling / cleaning the device is increased, resulting in a decrease in the operating rate of the device.

The present invention has been made to solve the above-mentioned problems, and a semiconductor capable of reducing dust in the reaction chamber and reducing the occurrence of defects in the semiconductor device manufactured in the reaction chamber. The purpose is to obtain manufacturing equipment.

[0009]

In a semiconductor manufacturing apparatus according to the present invention, a reaction chamber is depressurized and a reaction chamber is pressurized after performing a processing sequence and before performing the next processing sequence. A standby sequence including repeated operations is performed.

[0010]

In the semiconductor manufacturing apparatus according to the present invention, in the standby sequence, depressurization and pressurization in the reaction chamber are repeated while the semiconductor wafer is not in the reaction chamber, and dust adhering to the inside of the apparatus is lifted up. Since it was discharged to the outside of the device,
The amount of dust adhering to the semiconductor wafer can be reduced without lowering the operating rate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The semiconductor manufacturing apparatus according to one embodiment of the present invention has the same block configuration as that of the conventional apparatus, but the sequential control is different. FIG. 1 is a diagram showing a state of sequential control of a semiconductor manufacturing apparatus according to an embodiment of the present invention. In the figure, 12 is a standby sequence, 13 is a repeating portion in the standby sequence 12, and 14a and 14b are processing sequences. White circles and arrows in the figure are the same as in the conventional example. FIG. 2 is a flow chart showing a standby sequence according to an embodiment of the present invention.

Next, the operation will be described. Since the processing sequences 14a and 14b for forming a film on the surface of the semiconductor wafer 1 are the same as those in the conventional example, the description thereof will be omitted and the standby sequence will be described.

The semiconductor wafer 1 is unloaded from the boat 2 and the processing sequence 14a or 14b is completed (step 2).
After 1), the standby sequence 12 is started.
First, the boat loader 4 is raised to seal the reaction chamber 3. (Step 22).

Next, the opening / closing valve 6 for all the gas supplied into the reaction chamber 3 is closed, the opening / closing valve 8 for vacuuming is opened, and the inside of the reaction chamber 3 is evacuated by the vacuum pump 10 to, for example, 1 Pa or less ( Step 23).

After holding at 1 Pa or less for 1 minute, for example,
The on-off valve 6 for supplying an inert gas such as nitrogen is opened to raise the pressure in the reaction chamber 3. At this time, unlike the normal processing sequence, a large amount of gas of 1 liter or more per minute is supplied so that the dust adhering to the reaction chamber 3 rises into the reaction chamber 3 to cause a rapid pressure change. (Step 2
4).

Next, at that time, it is judged whether or not the processing sequence 14a or 14b is performed (step 25), and if the processing sequence 14a or 14b is not performed, the process returns to step 23. If the processing sequence 14a or 14b is to be performed, the process proceeds to step 26, the on-off valve 6 for supplying nitrogen is closed, and the reaction chamber 3 is evacuated.

Next, the evacuation is stopped, nitrogen is supplied to return the reaction chamber 3 to normal pressure (step 27), the boat loader 4 is lowered, and the reaction chamber 3 is opened (step 2).
8).

With the above, the standby sequence 12 ends, and the processing sequence 14a or 14b is started (step 29).

The dust lifted up in step 24 is discharged to the outside of the reaction chamber 3 when vacuuming in step 23 or step 26.

As described above, according to this embodiment, the dust in the reaction chamber is repeatedly removed by the standby sequence after performing the processing sequence and before the start of the next processing sequence. A semiconductor device with few defects can be manufactured without lowering the operating rate.

[0021]

As described above, according to the semiconductor manufacturing apparatus of the present invention, the pressure reduction / pressure increase in the reaction chamber is performed by the standby sequence after the processing sequence is performed and before the next processing sequence starts. Since this is repeated, it is possible to reduce the amount of dust in the reaction chamber and to reduce the occurrence of defects in the semiconductor device manufactured by this device.

[Brief description of drawings]

FIG. 1 is a diagram showing a state of sequential control of a semiconductor manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a standby sequence according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a semiconductor manufacturing apparatus that performs reduced pressure vapor deposition.

FIG. 4 is a diagram showing a state of sequential control of a conventional semiconductor manufacturing apparatus.

[Explanation of symbols]

 1 semiconductor wafer 2 boat 3 reaction chamber 4 boat loader 5 heater 6 open / close valve 7 flow control valve 8 open / close valve 9 exhaust control valve 10 vacuum pump 12 standby sequence 13 repeated part of standby sequence 14a processing sequence 14b processing sequence

Claims (1)

Claim: What is claimed is: 1. A semiconductor wafer is housed in a reaction chamber, a material gas is supplied while the reaction chamber is in a depressurized state, and the semiconductor wafer is heated to deposit a film on the surface of the semiconductor wafer. In a semiconductor manufacturing apparatus capable of setting at least two processing sequences for taking out the semiconductor wafer from the reaction chamber, an operation of depressurizing the reaction chamber between the processing sequence and the next processing sequence, A semiconductor manufacturing apparatus characterized by performing a standby sequence including a repetitive operation including an operation of introducing an inert gas into a room to increase the pressure.