JPH05347295A - Semiconductor wafer treating device - Google Patents

Abstract

PURPOSE:To provide a semiconductor wafer treating device which is able to adequately execute a series of treatment programs based on an atmospheric condition inside a reaction tube accurately obtained by monitoring residues of air which penetrates into the reaction tube from a surrounding atmosphere. CONSTITUTION:A semiconductor wafer treating device carries out processes such as a thermal oxidation process, a thermal diffusion process, and the like, where a monitoring means, which measures the residues of air penetrating into a reaction tube 1 through an inlet shutter 2 from surroundings when a semiconductor wafer 13 is taken in or out of the tube 1, is equipped with an oxygen concentration meter 12 connected in shunt to an exhaust pipe 5 led out of the reaction tube 1, and the measured signals obtained from the meter 12 are sent to a tube controller 7 to set a process sequence for adequately carrying out a series of treatment programs such as replacement of gas, rise in temperature, feed of process gas or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer process processing apparatus used for various process steps such as oxide film formation and impurity diffusion on a semiconductor wafer.

[0002]

2. Description of the Related Art As the above-mentioned semiconductor wafer processing apparatus, there are an atmospheric pressure thermal oxidation apparatus, a thermal diffusion apparatus and the like.
As is well known, these process processing apparatuses insert a semiconductor wafer into a quartz reaction tube around which a heater is arranged through an entrance shutter and replace the atmosphere in the tube with an inert gas (for example, nitrogen gas). , The reaction tube is heated to a predetermined reaction temperature, thermal oxidation,
A process gas corresponding to various process treatments such as thermal diffusion is supplied into the reaction tube to perform treatments such as oxide film formation and impurity diffusion on the semiconductor wafer.

On the other hand, when the inlet shutter is opened when the semiconductor wafer is taken in and out of the reaction tube, the air entrapped from the ambient atmosphere side enters the tube. In this case, if the processing program of the equipment is advanced with the air from the surroundings mixed in the reaction tube, crystal defects will occur in the oxide film grown on the surface of the wafer in the thermal oxidation process and the insulation characteristics will deteriorate. It is known that, after closing the inlet shutter of the reaction tube for that, after purging the air invading from the outside by flowing high-purity nitrogen gas or the like into the tube as described above, A process sequence is built in the controller so that the process goes to the next temperature rise and process gas supply process.

Further, in this case, in the conventional processing program, the time of the gas replacement process from the insertion of the semiconductor wafer into the reaction tube to the temperature rise of the tube and the start of the process gas supply is set by a timer in advance. The processing program is executed.

[0005]

However, in the method in which the gas replacement step is controlled by time like the above-mentioned conventional method, the airtightness of the shutter with the tube inlet closed is incomplete, or the exhaust pressure fluctuates. If this happens, gas replacement will not be completely performed within the set time, and some of the air entrapped from the outside inside the reaction tube will remain, and the process will proceed to the next temperature rise and process gas supply step where the semiconductor wafer is processed. There will be problems such as being caught.

The present invention has been made in view of the above points, and its purpose is to accurately grasp the state of the atmosphere in the tube by monitoring the residual amount of air invading the reaction tube from the surroundings and based on this. An object of the present invention is to provide a semiconductor wafer process processing apparatus capable of appropriately advancing a series of processing programs.

[0007]

In order to achieve the above object, in the process processing apparatus of the present invention, the residual amount of air that has entered the reaction tube from the surroundings through the inlet shutter is measured in the operation of taking a semiconductor wafer in and out. The monitoring means shall be provided. Further, using an oxygen concentration meter as the monitoring means, a configuration in which the oxygen concentration meter is branched and connected to the exhaust line of the reaction tube, and based on the measurement value obtained from the oxygen concentration meter in the process of gas replacement, the measured value There is an embodiment in which a process sequence is formed so that the processing program proceeds to the next temperature rising and process gas supply step under the condition that the value has decreased below the set reference value.

[0008]

By connecting an oxygen concentration meter as a monitoring means to the reaction tube as described above, the amount of air that has entered the tube from the surroundings due to the operation of taking in and out the semiconductor wafer, the leakage from the inlet shutter, etc. can be controlled. The oxygen concentration can be quantitatively measured correctly. Then, based on the measured value of the oxygen concentration meter, if a process sequence is set up so that the process controller of the reaction tube advances a series of processing programs, the oxygen concentration in the tube will drop to the set reference value in the gas replacement step. It is possible to properly execute a series of processing programs by avoiding a control problem such as starting the temperature rise of the tube and starting the supply of the process gas before the operation.

Further, in the thermal oxidizer, the oxygen concentration of the oxygen gas introduced into the reaction tube as the process gas or the oxygen concentration of water vapor can be monitored by the oxygen concentration meter to appropriately control the process treatment.

[0010]

Embodiment An embodiment of the present invention will be described below with reference to FIG. In the figure, 1 is a reaction tube, 2 is an inlet shutter, 3 is a heater, 4 is a gas introducing pipe, 5 is an exhaust pipe drawn near the inlet shutter, 6 is an exhaust pressure controller, and 7 is an exhaust pressure controller.
Is a tube controller for controlling temperature, gas, pressure, etc., 8 is a boat loader, and an oxygen concentration meter 12 is branched and connected to the exhaust pipe 5 via a gas cooler 9, a filter 10 and a suction fan 11. .. The gas cooler 9
Plays a role of cooling the high temperature gas taken in from the exhaust pipe side to a temperature below the allowable temperature of the oxygen concentration meter 12. Then, the semiconductor wafer 13 is mounted on the boat 14 and then loaded / unloaded into / from the reaction tube 1 via the boat loader 8.

The process sequence of such a process processing apparatus is constructed by the tube controller 7, and a series of processing programs are executed as follows in response to a control command from the controller. First, the processed semiconductor wafer 13
When the wafer is inserted into the reaction tube 1, the heating temperature of the heater 3 is lowered, the inlet shutter is opened while the inert gas is flowing in the tube, and the wafer 13 is reacted with the boat 14 by operating the boat loader 8. Insert into tube 1.
Then, the inlet shutter 13 is closed, and while the inert gas is continuously supplied, the air that has entered the tube from the inlet is exhausted to the outside of the system through the exhaust pipe 5 together with the inert gas, and the atmosphere in the tube is replaced with the inert gas. ..

On the other hand, in this gas replacement step, a part of the exhaust gas is sucked from the exhaust pipe 5 and taken into the oxygen concentration meter 12,
The oxygen concentration in the exhaust gas is measured and monitored, and the measured value is sent to the tube controller 7. Then, when the measured value obtained by the oximeter 12 reaches a preset reference value or less, that is, it is confirmed that the air entrained from the atmosphere side is sufficiently purged, the processing program proceeds to the next step, Tube controller 7
Command to control the heater 3 so that the temperature inside the furnace of the reaction tube 1 rises to a predetermined process temperature, the process gas supply is started to form an oxide film on the wafer 13 or diffuse impurities. Perform process processing. In the thermal oxidizer, the oxygen concentration of oxygen gas and water vapor supplied to the reaction tube 1 as the process gas can be monitored by the oxygen concentration meter 12 to appropriately control the supply amount of the process gas. On the other hand, when the process treatment of the semiconductor wafer 13 is completed, the supply of the process gas is stopped, the heating temperature of the heater 3 is lowered, the inlet shutter 2 is opened, and the boat loader 8 is operated to move the wafer 13 together with the boat 14 into a reaction tube. Take out from 1.

If the oxygen concentration does not fall below the set reference value even after a predetermined time has passed in the gas replacement step, it is judged that there is an abnormality in the system and the controller 7 issues an alarm. As a result, the maintenance personnel can inspect the entrance shutter 2, the exhaust pressure controller 6 and the like for any abnormality and take necessary recovery measures. When controlling multiple reaction tubes at once, connect one oximeter to each group, or connect one oximeter to the exhaust tube of each group of reaction tubes. It is also possible to connect in a switchable manner and monitor alternately.

[0014]

As described above, according to the process processing apparatus of the present invention, it is provided with the monitoring means for measuring the residual amount of the air invaded into the reaction tube when the semiconductor wafer is put in or taken out of the reaction tube. By using an oxygen concentration meter as the monitoring means and connecting it to an exhaust line drawn out from the vicinity of the inlet of the reaction tube, the residual air in the tube can be accurately monitored as the oxygen concentration.

If a process sequence is set up so that a series of processing programs can be carried out by the process controller of the reaction tube based on the measured value of the oxygen concentration meter, the oxygen concentration in the tube will be the set reference value in the gas replacement step. It is possible to properly execute a series of processing programs by avoiding control problems such as starting tube temperature rise and starting process gas supply before the temperature drops to 0. The process treatment of is obtained.

[Brief description of drawings]

FIG. 1 is a system flow diagram of a process processing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1 Reaction Tube 2 Inlet Shutter 3 Heater 4 Gas Supply Pipe 5 Exhaust Pipe 7 Tube Controller 12 Oxygen Concentration Meter (Monitoring Means) 13 Semiconductor Wafer

Claims (3)

[Claims] 1. A process processing apparatus for a semiconductor wafer used for process processing such as thermal oxidation and thermal diffusion, which is performed by inserting a semiconductor wafer into a reaction tube from the outside and replacing the atmosphere in the tube with an inert gas. In order to process the semiconductor wafer by starting the supply of temperature and process gas, a monitoring means was provided to measure the residual amount of air that has entered the reaction tube from the surroundings through the inlet shutter when the semiconductor wafer was taken in and out. A semiconductor wafer processing apparatus characterized by the above. 2. The process processing apparatus according to claim 1, wherein the monitoring means is an oximeter, and the oximeter is branched and connected to an exhaust line of a reaction tube. 3. The process processing apparatus according to claim 1, wherein a processing program is set up on the basis of a measured value obtained by an oxygen concentration monitoring means in the process of gas replacement, under the condition that the measured value falls below a set reference value. A process processing device for semiconductor wafers, characterized in that a process sequence is formed so as to proceed to the temperature rising and process gas supply steps.