JP2006005118A - Semiconductor manufacturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing apparatus which can prevent treatment property variations by plugging of gas discharge piping in vapor phase epitaxy equipment etc. <P>SOLUTION: A crystal resonator sensor 2 is installed at interior of a gas discharge piping 1, and wiring of a signal line 3 is performed so that a signal can be lead outside. Frequency variation measured by the crystal resonator sensor 2 is outputted to a data processor 4 such as a personal computer installed at exterior of the gas discharge piping 1. Correlation between frequency variation and closing status of the gas discharge piping is obtained. Limit of frequency variation until piping closing is established beforehand, and alarm is generated from the data processor 4 when a critical point is detected. Vapor phase epitaxy treatment is stopped when alarm is generated, internal cleaning work of the gas discharge piping 1 is performed, and pressure fluctuation by piping closing is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor manufacturing apparatus used in a semiconductor manufacturing process, and more particularly to a structure capable of monitoring a clogging state generated in an exhaust pipe by a raw material gas or the like.

  In an MOCVD apparatus or the like in semiconductor device manufacturing, a large amount of source gas is supplied to perform vapor phase growth in a chamber.

  However, in general, the raw material utilization efficiency during vapor phase growth is low, and most of the gas supplied to the chamber is discharged to an external gas processing device or the like through an exhaust pipe. When a large amount of gas flows through the exhaust pipe, reaction products accumulate in the pipe and cause clogging of the pipe. If the exhaust pipe is clogged, the exhaust volume of the chamber for vapor phase growth will fluctuate, and the film thickness and film quality of the grown thin film will tend to be uneven. Therefore, it is necessary to clean the reaction products in the exhaust pipe regularly. There is.

  However, the exhaust pipe is generally made of a metal material such as SUS, and the reaction product accumulates in a viewing window for visually checking the inside of the pipe, so that the clogging in the exhaust pipe is visually confirmed. It was difficult.

Conventional methods for monitoring exhaust pipes include a method of measuring the differential pressure of the exhaust pipes to grasp the clogging situation, and a bypass pipe that bypasses gas from the exhaust pipe, and a moving member is accommodated in the bypass pipe. There is a method of detecting that there is a clogged pipe if it does not move (see, for example, Patent Document 1).
JP-A-8-191039

  However, the conventional exhaust pipe monitoring method has the following problems. First, in the method of grasping the blockage state by the differential pressure of the exhaust pipe, since the inside of the pipe is evacuated to a low pressure, the blockage of 80% to 90% has already occurred at the time when the fluctuation of the differential pressure is detected. There is a problem that the abnormality detection is slow. Also, in the method of detecting the moving member of the bypass pipe, the abnormality in the bypass pipe cannot be detected unless the exhaust pipe is almost clogged, so the abnormality detection is slow and the inside of the actual exhaust pipe is not monitored. Has a problem.

  Therefore, in view of the above-described problems, the present invention provides a semiconductor manufacturing apparatus having a structure capable of constantly monitoring a clogging state inside an exhaust pipe and detecting an abnormality at an early stage.

  In order to solve the above problems, a semiconductor manufacturing apparatus of the present invention is a semiconductor manufacturing apparatus for introducing a processing gas into a chamber and processing a substrate, and an exhaust pipe is connected to the vacuum processing apparatus. A quartz crystal sensor installed in the exhaust pipe, and a data processing device for collecting the output signal of the crystal vibrator sensor outside the exhaust pipe and calculating and determining a maintenance timing of the exhaust pipe. Yes.

  When the resonance frequency of the crystal resonator sensor reaches a predetermined frequency change amount determined in advance from the correlation between the change in the resonance frequency of the crystal resonator sensor and the closed state of the exhaust pipe, the chamber is transferred from the data processing device. It is preferable that a signal for stopping the processing at is sent.

  More preferably, the crystal oscillator sensor is installed in a removable external port provided in the exhaust pipe.

  The semiconductor manufacturing apparatus is preferably an MOCVD apparatus.

  As described above, according to the present invention, an appropriate maintenance timing is determined by detecting in real time the clogged state of the reaction product inside the exhaust pipe, and the pressure fluctuation inside the chamber due to the clogging of the exhaust pipe is suppressed, and uniform. A process such as vapor phase growth can be performed with a suitable film thickness and film quality.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an exhaust pipe of an MOCVD apparatus in an embodiment of the present invention. In FIG. 1, 1 is an exhaust pipe, 2 is a crystal oscillator sensor, 3 is a signal line, and 4 is a data processing device. In the above configuration, an embodiment of the present invention will be described.

  The quartz oscillator sensor 2 is a sensor that measures a change in thickness of a quartz piece due to adhesion of a substance to an electrode by a change in resonance frequency. The quartz resonator sensor is generally known as a sensor that can stably detect a very small amount of change in the amount of adhesion, and is used for the purpose of managing the accumulated film thickness in the semiconductor manufacturing field. The resonance frequency of the crystal unit is expressed by the following formula.

f = 1 / 2t (√C / ρ) (Formula 1)
Here, t is the thickness of the crystal piece, C is the elastic constant of the attached substance, and ρ is the density of the attached substance.

  The change in the resonance frequency is determined by the change in the elastic constant due to the attached substance and the thickness dimension when the attached thickness of the substance is converted into the crystal density, and as a result, it can be converted into the weight of the attached substance.

  In the case of a dry type in which the change in the elastic constant C can be ignored as in the present embodiment, the frequency change is caused only by weight. A gas exhausted from a chamber (not shown) for vapor phase growth flows through the exhaust pipe 1. The exhausted gas is not used for vapor phase growth, and a gas containing a large amount of unreacted components flows. For this reason, the residual gas reacts while flowing in the exhaust pipe 1 and becomes a reaction product and accumulates in the exhaust pipe 1.

  Since the quartz oscillator sensor 2 is installed in the exhaust pipe 1, reaction products are continuously deposited until the quartz oscillator sensor 2 is regularly cleaned. The frequency change output from the crystal oscillator sensor 2 is transmitted to the data processing device 4 installed outside the exhaust pipe 1 through the signal line 3, and the data processing device 4 always samples the frequency change. Correlation data between the frequency change output from the quartz crystal sensor 2 and the blockage inside the exhaust pipe 1 is clarified in advance, and an alarm is generated from the data processing device 4 when the exhaust pipe 1 needs to be periodically cleaned. Perform regular cleaning. By performing appropriate periodic cleaning, pressure fluctuations in the chamber are suppressed, and vapor deposition with a uniform film thickness and film quality is performed.

Hereinafter, more specific embodiments will be described. A crystal resonator sensor 2 is installed inside the exhaust pipe 1 made of a SUS member, and the signal line 3 is wired so that a signal can be taken out to the outside. Considering the case where this configuration is applied to an MOCVD apparatus, in this apparatus, a gas containing P (phosphorus) such as PH ₃ (phosphine) is used for chemical vapor deposition of a desired film on a substrate. Often used in large quantities.

  However, in general, the utilization efficiency of the raw material gas at the time of vapor phase growth is low, and a large amount of unreacted gas exhausted from the chamber flows in the exhaust pipe. P (phosphorus) has a property of solidifying at a low temperature. Therefore, unreacted P (phosphorus) is solidified in the exhaust pipe 1 and is deposited in the pipe 1 as a reaction product. Further, since the crystal resonator sensor 2 is installed inside the pipe 1, reaction products accumulate on the crystal resonator sensor 2 and the resonance frequency changes with time.

  The frequency change measured by the crystal oscillator sensor 2 is output to a data processing device 4 such as a personal computer installed outside the exhaust pipe 1. The data processing device 4 continuously collects signals from the crystal resonator sensor 2 and manages the history of frequency changes.

  The correlation between the frequency change and the exhaust pipe blockage state is obtained, the limit of the frequency change amount until the pipe is blocked is set in advance, and an alarm is generated from the data processing device 4 when the limit point is detected. When the alarm is generated, the vapor phase growth process is stopped, the inside of the exhaust pipe 1 is cleaned, and the pressure fluctuation due to the pipe blockage is prevented. By performing these operations, uniform vapor phase growth can be performed for both film thickness and film quality.

  If the exhaust pipe 1 is provided with a removable external port (not shown) and the crystal resonator sensor 2 is installed in the external port, the quartz resonator sensor 2 is cleaned and replaced when the exhaust pipe 1 is periodically cleaned. Becomes easier.

  Also, when installing multiple quartz crystal sensors for one exhaust pipe, or when installing quartz crystal sensors in each exhaust pipe in a multi-chamber semiconductor manufacturing facility with multiple exhaust pipes By connecting the frequency changes from each crystal oscillator sensor to a single personal computer, the exhaust pipes at multiple locations / systems can be centrally managed by the personal computer, and only an appropriate maintenance time is determined. In addition, it is possible to extract a problem such as a difference in film formation rate between chambers caused by unevenness of the blocking state.

  Note that although the MOCVD apparatus has been described as an example in this embodiment mode, a substrate is set in another apparatus, for example, a vacuumed chamber, and an etching gas is supplied to the substrate or a specific layer formed on the substrate. The same effect can be obtained when applied to a dry etching apparatus for processing, a CVD apparatus using an inorganic source gas, or the like.

  In addition, when applied to a CVD apparatus, the present invention may be used not only for the low pressure CVD in which the growth process is started after the chamber is evacuated but also for the atmospheric pressure CVD apparatus.

  The semiconductor manufacturing apparatus of the present invention is useful particularly when applied to an MOCVD apparatus or the like as an apparatus that can prevent fluctuations in processing characteristics due to clogging of exhaust pipes.

The schematic diagram which shows the exhaust piping of the MOCVD apparatus in embodiment of this invention

Explanation of symbols

1 Exhaust piping 2 Quartz crystal sensor 3 Signal line 4 Personal computer

Claims (4)

A semiconductor manufacturing apparatus for introducing a processing gas into a chamber and processing a substrate,
An exhaust pipe is connected to the vacuum processing apparatus,
A quartz crystal sensor is installed inside the exhaust pipe,
A semiconductor manufacturing apparatus provided with a data processing device that collects output signals of the crystal oscillator sensor outside the exhaust pipe, performs arithmetic processing, and determines a maintenance time of the exhaust pipe. When the resonance frequency of the crystal resonator sensor reaches a predetermined frequency change amount determined in advance from the correlation between the change in the resonance frequency of the crystal resonator sensor and the closed state of the exhaust pipe, the chamber is transferred from the data processing device. The semiconductor manufacturing apparatus according to claim 1, wherein a signal for stopping the processing at is sent. 3. The semiconductor manufacturing apparatus according to claim 1, wherein the crystal resonator sensor is installed in a removable external port provided in the exhaust pipe. The semiconductor manufacturing apparatus according to claim 1, wherein the semiconductor manufacturing apparatus is an MOCVD apparatus.

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