CN100514034C - Method for judging maintenance of times of semiconductor production apparatuses - Google Patents

Abstract

In order to efficiently carry out the purification treatment after maintenance, and at the same time to reliably know the end of the purification treatment, shorten the time required for the purification treatment, and restore the CVD device, in the heating and circulation purification treatment after maintenance, the heat conduction Gases with high coefficients and inert gases are used as purge gases. In the purge treatment before the formation of the semiconductor film, evacuation and introduction of inert gas are repeated several times. Also, in order to determine an appropriate maintenance period for semiconductor manufacturing equipment that performs corrosive gas treatment in the reaction chamber, the corrosive gas maintenance period is determined in accordance with changes in water concentration when corrosive gas treatment is repeated.

Description

Method for judging maintenance period of semiconductor manufacturing equipment

This application is a branch of an invention patent application with an application date of August 31, 2000, a divisional submission date of October 17, 2003, an application number of 200310102823.7, and an invention title of "Purification method for a chemical vapor deposition device". The application No. 200310102823.7 is the application date of August 31, 2000, the application number is 00131310.X, and the title of the invention is "chemical vapor deposition device and its purification method and semiconductor manufacturing device". Divisional application.

technical field

Aspects of the present invention relate to a CVD (Chemical Vapor Deposition) apparatus and a cleaning method thereof, and particularly to a structure of a CVD apparatus and a cleaning method thereof which can shorten the time required for cleaning after maintenance.

In addition, the present invention relates to a moisture monitoring device for monitoring moisture contained in a corrosive gas during processing, for example, when epitaxial growth is performed on a silicon substrate disposed in a reaction chamber using a corrosive gas, and a semiconductor manufacturing device and a semiconductor manufacturing device equipped with the device. Method for judging maintenance period of manufacturing equipment.

Background technique

A CVD apparatus is an apparatus that grows a semiconductor film on a wafer by chemically reacting semiconductor material gas introduced into a reaction chamber (reactor) on the substrate (wafer). However, since all the material gases cannot be reacted on the wafer in principle, by-growths are attached to various places on the inner wall surface of the reactor. Since such by-growths affect film growth as particles or the like and prevent formation of a good-quality film, cleaning (maintenance) of the inner wall surface of the reactor is necessary.

For example, in a CVD apparatus for growing a thick film, maintenance must be performed about once every 3 to 4 days. However, during maintenance, since the device is exposed to the atmosphere and cleaned with ethanol, a large amount of air is brought in, and moisture is adsorbed on the inner wall surface of the device.

During the growth of the semiconductor film, if there is moisture in the atmosphere, it reacts with the semiconductor material gas to generate metal impurities or particles, deteriorating the film quality. Therefore, after maintenance, the interior of the device must be purged with an inert gas such as high-purity nitrogen before growing the membrane, and the water concentration must be reduced to such an extent that it does not adversely affect the membrane quality.

However, the inside of the CVD apparatus has a very complicated shape, and since the adsorption force of water molecules is very strong, it takes a long time to remove the water after maintenance, which greatly affects the operating efficiency of the apparatus.

In order to shorten the maintenance time of equipment including purification, various methods such as vacuuming, heat purification (baking), use of hydrogen, or a combination of them have been implemented conventionally. However, since conditions and combinations of vacuuming and baking are determined empirically, it is difficult to optimize the purification method.

In addition, after cleaning to some extent, the film is actually grown, and the completion of cleaning is judged from the evaluation of its quality. Therefore, material gas and time are wasted in growth until a film of product-level quality is obtained. It is called discarded film (すてエピ), but the number of discarded films will increase significantly due to the difference in the time required for purification due to the usage time and maintenance of the CVD device.

In addition, in recent years, as silicon wafers used as MOS devices, epitaxial wafers in which single-crystal silicon thin films (epitaxial layers) are vapor-grown on silicon substrates with extremely low resistivity at predetermined impurity concentrations are produced by epitaxial crystal growth equipment. The device arranges a silicon substrate in a processing chamber, flows a corrosive source gas, and performs epitaxial growth on the substrate. In addition, in this apparatus as well, the polysilicon attached to the inside of the processing chamber is etched using hydrogen chloride as an etching gas.

In addition, in semiconductor manufacturing processes such as LSI, various CVD apparatuses for forming thin films on substrates using corrosive gases or etching apparatuses for patterning are used.

These semiconductor manufacturing devices use corrosive gases such as hydrogen chloride gas and ammonia gas at extremely high concentrations. Even if some moisture is contained in them, it is easy to cause damage to Corrosion of metal parts causes harmful pollution due to metals (heavy metals) generated from metal parts. In addition, moisture entering the processing chamber reacts with by-growths adhering to the processing chamber wall and the exhaust pipe, and may cause particles. Therefore, although various measures are taken to reduce moisture in the processing chamber, it is difficult to completely eliminate the moisture, and maintenance of the device must be carried out regularly, that is, the opening of the processing chamber and cleaning of internal parts (quartz jigs, etc.) must be performed regularly. Conventionally, for example, in the case of a leaf type CVD apparatus, the time for maintenance is determined based on the cumulative number of processed wafers.

However, the above conventional method of judging the maintenance time has the following problems. In other words, depending on the work content during maintenance and the opening time of the processing chamber, the amount of water entering the processing chamber actually varies each time maintenance is performed, and when the maintenance period is judged based on the cumulative number of wafers processed as in the past Under the circumstances, in fact, it has nothing to do with the moisture entering the treatment room, and the maintenance is carried out every time a certain number of treatments are reached, and the maintenance may not be carried out at an appropriate time. For example, at the time of the previous maintenance, when more water entered than the assumed amount, if the processing is not performed until the predetermined cumulative number of sheets is processed, there is a possibility that a good film quality cannot be obtained. In addition, when the amount of water entering during the previous maintenance is relatively small, maintenance is performed earlier than the actually necessary maintenance time, and the number of times of maintenance increases, resulting in a decrease in productivity.

In addition, in order to reduce the moisture in the processing chamber, it is required to quantitatively analyze the moisture in the corrosive gas in the processing chamber with high sensitivity.

As a moisture meter for monitoring moisture in gas, for example, the quartz oscillator method for monitoring the frequency change of a quartz oscillator and the electrostatic capacity method for absorbing moisture in the gas and monitoring the change in capacitance are well known, but since such a moisture meter must be directly In contact with gas, so in the case of corrosive gases, monitoring cannot be performed due to the corrosive nature of the gas.

Therefore, in recent years, for example, in JP-A-5-99845 and JP-A-11-183366, the following moisture meters have been disclosed. moisture meter. In this laser moisture meter, corrosive gas is introduced into the measuring tube, and a laser beam of a predetermined wavelength is incident into the measuring tube at the same time. By analyzing the transmitted laser light, impurities such as moisture are detected from the intensity of the absorption wavelength, and it is not necessary to adsorb corrosive gas. High sensitivity and high-speed monitoring are possible.

However, the monitoring device using the above-mentioned conventional moisture meter has the following problems. That is to say, after the corrosive gas is heated in the reaction chamber, part of it is introduced into the above-mentioned moisture meter through the sampling pipe, but the side reaction growth is deposited on the inner wall of the sampling pipe leading to the moisture meter, and the sampling pipe may be blocked. sex. Therefore, it is difficult to constantly monitor the moisture in the corrosive gas during processing, that is, to perform in-situ monitoring.

In recent years, as a device for measuring the moisture concentration in the corrosive gas, for example, in Japanese Patent Application Laid-Open No. 5-99845 and Japanese Patent Laid-Open No. 11-183366, etc., it is disclosed to monitor the incident laser light passing through the tubular unit body connected to the processing chamber. The laser absorption spectrum of the laser moisture meter. Since this laser moisture meter can measure without contact with gas, even corrosive gas can be measured with high precision.

Contents of the invention

Therefore, the first object of the present invention is to provide a CVD cleaning method, which can efficiently perform cleaning after maintenance, and at the same time, can reliably know the completion of cleaning, shorten the time required for cleaning, and quickly perform CVD equipment. recovery.

In addition, a second object of the present invention is to provide a method for judging a maintenance time of a semiconductor manufacturing apparatus capable of judging an appropriate maintenance time.

According to the purification method of the CVD apparatus of the present invention, the purification treatment of the reactor can be carried out efficiently, and in addition, because the time when the film growth starts can be reliably known, so the improvement of the operation efficiency of the CVD apparatus and the elimination of the discarded film can be realized, Waste of material gas and waste of time can be reduced.

In order to achieve the above object, according to the present invention, there is provided a method for judging the maintenance period of a semiconductor manufacturing device, wherein the method for judging the maintenance period of a semiconductor manufacturing device in which a corrosive gas is processed in a reaction chamber is judged, wherein the method is characterized in that, after performing the etching During corrosive gas treatment, a moisture meter connected to the reaction chamber is used to monitor the moisture concentration in the reaction chamber, and the maintenance period is determined according to changes in the moisture concentration when the corrosive gas treatment is repeated.

In this method for judging the maintenance period of semiconductor manufacturing equipment, since the moisture meter connected to the reaction chamber is used to monitor the moisture concentration in the reaction chamber when the corrosive gas treatment is performed, the water concentration in the reaction chamber is determined according to the change in the moisture concentration when the corrosive gas treatment is repeated. The maintenance period is determined based on the corresponding change of the moisture concentration and the amount of moisture actually entering the reaction chamber, so the appropriate maintenance period can be accurately judged. Therefore, it is possible to always maintain the good condition of the device, and at the same time, the number of times of maintenance can be reduced and the period of maintenance can be extended, so that productivity can be improved.

In addition, in the method for judging the maintenance time of a semiconductor manufacturing device according to the present invention, the cumulative amount of water entering the reaction chamber from the previous maintenance may be calculated based on the change in the water concentration, and the above-mentioned maintenance period.

In this method for judging the maintenance period of a semiconductor manufacturing apparatus, since the maintenance period is determined based on the accumulated amount of moisture calculated from the change in moisture concentration, the amount of moisture actually entering the reaction chamber can be accurately estimated, and an appropriate maintenance period can be easily determined.

Furthermore, in the method for judging the maintenance period of a semiconductor manufacturing device according to the present invention, when the corrosive gas treatment is performed, the pressure in the reaction chamber may be monitored with a pressure gauge connected to the reaction chamber, and the corrosive gas may The maintenance period is determined by the pressure change and the accumulated amount of moisture during the treatment.

In this method of judging the maintenance period of semiconductor manufacturing equipment, since the maintenance period is determined according to the pressure change in the reaction chamber and the accumulated amount of moisture, the flow state of the piping of the exhaust system is detected from the pressure change in the reaction chamber, such as when it is blocked. The resulting pressure fluctuations, etc., can be considered in the moisture concentration to determine a more appropriate maintenance period.

In addition, the moisture meter of the method for judging the maintenance period of the semiconductor manufacturing apparatus of the present invention is a laser moisture meter, and measures the laser absorption spectrum of the laser light incident and transmitted through the tubular unit body connected to the reaction chamber.

In other words, in the method for judging the maintenance period of the semiconductor manufacturing equipment described above, since the above-mentioned laser moisture meter is used as the moisture meter, the moisture concentration in the reaction chamber can be accurately measured even during processing, and maintenance can be determined with high accuracy. period.

Description of drawings

FIG. 1 is a system diagram showing one embodiment of the CVD apparatus of the present invention.

Fig. 2 is a graph showing the temporal change of the discharge amount of water molecules during baking purification using only nitrogen gas.

Fig. 3 is a graph showing the temporal change of the discharge amount of water molecules during baking purification using a nitrogen-hydrogen mixed gas.

FIG. 4 is a graph showing the relationship between the number of batch purifications and the molecular weight of water in exhaust gas over time.

5 is a schematic overall plan view of an epitaxial crystal growth apparatus showing an embodiment of a method for judging a maintenance period of a semiconductor manufacturing apparatus according to the present invention.

6 is a cross-sectional view showing a structure of a moisture meter for processing according to an embodiment of a method for judging a maintenance period of a semiconductor manufacturing apparatus according to the present invention.

7 is a graph showing changes in water concentration monitored when film formation processes are repeated in one embodiment of the method for judging the maintenance period of a semiconductor manufacturing apparatus according to the present invention.

8 is a schematic overall plan view showing the moisture monitoring device of the present invention and an epitaxial crystal growth device which is an embodiment of a semiconductor manufacturing device equipped with the moisture monitoring device.

9 is a piping diagram showing the configuration of the moisture monitoring device of the present invention and the moisture monitoring device of an embodiment of a semiconductor manufacturing apparatus equipped with the moisture monitoring device.

10 is a cross-sectional view showing the structure of a moisture monitoring device according to the present invention and a laser moisture meter according to an embodiment of a semiconductor manufacturing device equipped with the moisture monitoring device.

Detailed ways

A. CVD apparatus and purification method of CVD apparatus

FIG. 1 is a system diagram showing an embodiment of the CVD apparatus of the present invention. The CVD apparatus main body 110 has a reactor 112 provided with a gas flow passage 111 inside, a dry box 113 connected to the reactor 112, and a processing chamber 115 equipped with a rotating mechanism of a susceptor 114, a heating wire, and the like.

In the reactor 112, a material gas supply path 121 for supplying a semiconductor material gas for forming a semiconductor film, an inert gas supply path 122 for supplying an inert gas used for purification, and a heat conduction gas supply path 122 for supplying hydrogen, helium, etc. mixed in the purge gas are connected. A high thermal conductivity gas supply path 123 for a gas with a high coefficient and a reactor exhaust path 131 for exhausting gas from the reactor 112 . In addition, the dry box 113 and the processing chamber 115 are connected to purge gas supply paths 124 and 125 for supplying purge gas, respectively, and the dry box 113 is connected to a dry box exhaust path 132 .

The reactor exhaust path 131 is branched from the main exhaust path 133 into an analysis path 134 and a vacuum exhaust path 135, and the branch path 134 is provided with a moisture meter 141 for measuring the amount of moisture in the gas discharged from the reactor 112. , in the vacuum evacuation path 135, a vacuum pump 142 for evacuating the inside of the reactor 112 is provided. On the downstream side of the main exhaust path 133 , the lead-out path 136 from the vacuum pump 142 , the lead-out path 137 from the moisture meter 141 , and the dry box exhaust path 132 merge and are connected to the decontamination device 143 .

As the moisture meter 141, a moisture meter capable of monitoring on the spot and continuously monitoring is used. In addition, even after maintenance, since the gas discharged from the CVD apparatus contains many reaction growths, and the reaction growths evaporated by baking are attached after cooling, it is desirable that the detection part (unit 141a) of the moisture meter 141 is non-contact, The exhaust gas passage portion may be heated. Moreover, since most CVD devices do not have a pressure-resistant design, the interior is also below normal pressure during purification, so sampling can be performed therefrom. As a single moisture meter 141 satisfying these conditions, a laser spectrometer utilizing near-infrared absorption spectrometry can be enumerated. This spectrometer can also heat all the measured components except that the laser as the light source and the detection part are not in contact with the measured components. As for the flow path of gas, a vacuum pump (not shown in the figure) is provided in the rear stage of the unit 141a.

The CVD apparatus at the time of film growth supplies a semiconductor material gas of a predetermined composition from the material gas supply path 121 to the inside of the reactor 112 while heating the wafer (not shown) loaded on the susceptor 114 to a predetermined temperature. A semiconductor film is grown on the wafer. At this time, the exhaust gas discharged from the reactor 112 is discharged from the decontamination device 143 through the reactor exhaust path 131 , the filter 151 , the valve 152 , the preliminary filter 153 , and the valve 154 . In addition, from the purge gas supply path 124, 125, the purge gas used to maintain the clean state is respectively introduced into the drying box 113 and the processing chamber 115. The exhaust gas in the exhaust path 133 merges, and the gas in the processing chamber 115 flows into the connected reactor 12 and is discharged together with the exhaust gas.

The purification process after the atmosphere is opened due to the maintenance work is carried out as follows. First, the valves of each supply path are closed, the valve 152 and the valve 156 of the analysis path 134 are closed, and at the same time, the valve 157 of the vacuum exhaust path 135 is opened. The operation of the vacuum pump 142 is operated in the state where the reactor 112 is evacuated (vacuum cleaning), and the operation of introducing an inert gas such as nitrogen gas from the inert gas supply path 122 into the reactor 112 to restore the pressure is repeated. Batch purification. At this time, in the cell 141 a of the moisture meter 141 , high-purity nitrogen or the like supplied from the path 141 b is in a state of being circulated. Next, an inert gas such as nitrogen is supplied from the inert gas supply path 122, and at the same time, a gas with high thermal conductivity such as hydrogen is supplied from the high thermal conductivity gas supply path 123, and the inside of the reactor 112 is heated to a predetermined temperature to perform heating circulation purification (baking purification) . At this time, the vacuum pump 142 is stopped, the valve 157 is closed, the valve 152 is opened, and the valves 158 and 159 of the moisture meter 141 are opened to introduce a part of the exhaust gas into the moisture meter 141 to continuously measure the moisture content in the exhaust gas. Then, the batch purification and baking purification are repeated until the moisture content in the exhaust gas reaches a predetermined concentration or less.

In this way, as a purge gas supply path, an inert gas supply path 122 and a high thermal conductivity gas supply path 123 are provided, and by using a purge gas that properly mixes an inert gas and a gas with a high thermal conductivity during the baking purification process, it is different from using only Compared with the case of purging with inert gas, the time required for purging can be greatly shortened. In addition, the mixing ratio of the inert gas and the gas having a high thermal conductivity can be appropriately set according to actual film formation conditions.

Furthermore, by providing the moisture meter 141 that continuously measures the moisture content in the exhaust gas, it is possible to reliably know the end point of the purification process. In addition, by providing the vacuum pump 142, the purge treatment of the reactor 112 before film formation, the introduction of the purge gas, and the batch purge of the vacuum purge composition are repeated multiple times, enabling short-time and high-efficiency purge treatment.

In addition, by appropriately combining the above-mentioned batch cleaning and baking cleaning, it is possible to perform optimal cleaning treatment according to the state of the CVD apparatus.

Example

First, the purification effect of the conventional purification treatment using only an inert gas and the purification treatment using a gas mixture of an inert gas and a gas with a high thermal conductivity was compared. After the moisture concentration in the gas discharged from the reactor 112 is fully purified in advance to 0.1 ppm or less, the door between the reactor 112 and the dry box 113 is opened while nitrogen gas is flowing during the actual film formation operation. 15 minutes of standard time.

Then, after the door is closed, only nitrogen gas is passed through the reactor 112 as a purge gas, and the discharge amount of water molecules in the exhaust gas is stabilized until the heating wire is heated to 120° C., and the heating of the heating wire is stopped after 40 minutes have elapsed. Heat to lower the temperature slowly. The moisture content in the exhaust gas during this baking and cleaning period was measured. Figure 2 shows the results. In addition, the supply amount of nitrogen gas (flow rate per minute) was 24 liters from the start of purification to 14 minutes, 34 liters from 14 minutes to 15 minutes, 38 liters from 15 minutes to 55 minutes, and 184 liters after 55 minutes. Lift.

In addition, a nitrogen-hydrogen mixed gas mixed with nitrogen and hydrogen was used as the purge gas during the baking purge, and the moisture content in the exhaust gas was similarly measured. Figure 3 shows the results. At this time, the supply amount of each gas of nitrogen and hydrogen (flow rate per minute) was 20 liters of nitrogen and 4 liters of hydrogen from the start of purification to 11 minutes, 30 liters of nitrogen and 4 liters of hydrogen from 11 minutes to 12 minutes, and from From 12 minutes to 53 minutes, nitrogen was 78 liters, hydrogen was 60 liters, and after 53 minutes, only nitrogen was 184 liters.

In addition, since the moisture content in Fig. 2 and Fig. 3 ignores the difference in the flow conditions of the purge gas, it is represented by the discharge amount of water molecules per unit time on average. In addition, high-purity nitrogen from the purge gas supply path 124 always flows through the drying box 13, and the moisture concentration inside is constant.

Comparing Fig. 2 and Fig. 3, the discharge amount of water molecules rises sharply before reaching a peak in about 15 minutes after the start of heating, and then decreases slowly while maintaining 1200°C. In addition, the discharge amount of water molecules during heating is smaller only with nitrogen, and the discharge amount of water molecules after heating is stopped is smaller with nitrogen-hydrogen mixed gas.

The time from heating stop (beginning of submission) to the discharge of water molecules reaching the level of 2×10s17s[unit/min] shows that nitrogen-hydrogen mixed gas is faster than 10 minutes, which can shorten the time required for purification treatment. In addition, since the thermal conductivity of hydrogen is about 10 times larger than that of nitrogen, even at the same temperature of the filament, the temperature of the wall surface of the reactor and the surrounding small parts is higher than that of the mixed gas of nitrogen and hydrogen. The total number of water molecules discharged in the measurement during the period was 3.94×10 ²⁰ [units] in the case of nitrogen alone, and increased to 8.20×10 ²⁰ [units] in the case of nitrogen-hydrogen mixed gas. That is to say, by mixing hydrogen with high thermal conductivity into the purified gas to increase the thermal conductivity of the purified gas, it is obvious that the efficiency of baking purification can be improved. The same result can be obtained even if helium, which has a high thermal conductivity like hydrogen, is used.

Next, an experiment was performed to confirm the repeated effect of batch cleaning using vacuum cleaning simultaneously. As above, after the purification was performed until the moisture concentration in the exhaust gas became 0.1 ppm or less, the door between the reactor 112 and the drying box 113 was opened for 15 minutes. At the time of 0-time batch purification, after closing the door, the reactor 112 was kept in a state of flowing 24 liters of nitrogen per minute at normal temperature, and the water concentration in the exhaust gas was measured.

When purging in batches, after closing the door, stop the supply of nitrogen, carry out vacuum exhaust until the inside of the reactor 112 reaches 6.65Pa, then, circulate 24 liters of nitrogen per minute, measure the moisture in the exhaust gas concentration. In the case of two batch purges, after the first evacuation, nitrogen was introduced into the reactor 112 until atmospheric pressure was reached, the seal was interrupted for 10 minutes, and then the second evacuation was carried out. That is, door opening and closing, vacuuming, nitrogen gas introduction, holding at atmospheric pressure, vacuuming, nitrogen gas introduction, and flow are performed in this order.

FIG. 4 shows the changes in the respective water concentrations at the time of 0 batch cleaning, 1 batch cleaning, and 2 batch cleaning, starting from the time when the door is closed. As can be seen from FIG. 4 , even considering the time required for vacuuming, the time required for the purification process (drying down) can be shortened by performing batch purification. In addition, it is clear that the effect is greater by repeating twice than once.

At this time, by continuously measuring the moisture content with the moisture meter 141, it can be known that the moisture content in the exhaust gas has reached 0.1 ppm or less when about 110 minutes have elapsed when the batch purification is repeated twice. Start the usual membrane generation operation. In addition, even if there is a difference in the cleaning effect due to the use history of the CVD apparatus, since the completion of the cleaning process can be known with certainty, there can be almost no conventional discarding film.

B. How to determine the maintenance period of semiconductor manufacturing equipment

Hereinafter, an embodiment of a method for judging a maintenance period of a semiconductor manufacturing apparatus according to the present invention will be described with reference to FIGS. 5 to 7 .

In these figures, reference numeral 1 denotes a processing chamber, 2 denotes a transfer chamber, 3 denotes a delivery load lock chamber, 4 denotes a delivery load lock chamber, and 5 denotes a moisture monitoring device.

FIG. 5 is a diagram showing a state where the semiconductor manufacturing apparatus of the present invention is used, for example, in a leaf-type epitaxial crystal growth apparatus. This epitaxial crystal growth apparatus, as shown in FIG. 5, is equipped with: three processing chambers (reaction chambers) 1 made of quartz, which are hollow airtight containers in which silicon substrates (substrates) W are disposed; transport chambers 2 , when the silicon substrate W is sent into these processing chambers 1, the atmosphere is replaced in the closed space inside; it is sent into the load lock chamber 3, and the silicon substrate W before processing is sent into the transportation chamber 2; and the load is sent out. Lock the chamber 4 and take out the processed silicon substrate W from the transport chamber 2 .

Each of the processing chambers 1 is provided with a moisture meter for processing that samples the gas introduced into the processing chamber 1 and monitors moisture contained in the gas, and a pressure gauge 7 that monitors the pressure in the processing chamber 1 .

Furthermore, even in the transport chamber 2, a transport system moisture meter 6 for monitoring moisture in the internal atmosphere is provided. The transportation system moisture meter 6 is, for example, preferably a laser moisture meter similar to the laser moisture meter 10 described below with good accuracy and response speed, or it may be an electrostatic capacitance that absorbs moisture in an alumina capacitor or the like to monitor changes in its capacitance. The moisture meter of the method and the moisture meter of the mass analysis method, etc.

The processing chamber 1 is connected to a gas supply source (omitted in the figure) such as corrosive gas, and the gas (SiCl ₂ H ₂ , SiCl ₃ H, HCl, H ₂ , N ₂ , B ₂ H ₆ , PH ₃ , etc.), through the gas exhaust system, can be connected with the exhaust gas treatment equipment (omitted in the figure), and the corrosive gas after the reaction will be supplied in the processing chamber 1 to the exhaust gas treatment equipment.

As shown in Figure 6, the described moisture meter 5 that is used for processing is equipped with: sampling pipe 9, passes through the gas exhaust system and valve (omitted in the figure) of processing chamber 1, and its one end connects sampling conduit; Moisture meter body 10, monitoring Moisture contained in the corrosive gas from the processing chamber 1 connected to the other end of the sampling pipe 9 ;

The moisture meter main body 10 is provided with a tubular unit body 19 inside the housing 10a. One end of the tubular unit main body 19 is connected to the sampling pipe 9, and the other end is connected to the connection pipe 11. Tubular unit body 19 is equipped with translucent window material 19a at both ends, on the outside of one translucent window material 19a, the semi-conductor laser LD that produces infrared laser L (wavelength 1.3～1.55 μm) variable wavelength is oppositely arranged, On the outside of the other translucent window material 19a, a photodetector PD that receives infrared laser light L transmitted through the tubular unit body 19 and converts the intensity of the received light into an electrical signal is disposed opposite to each other.

Further, a strip-shaped heating wire 20 connected to a current supply source (not shown) is wound around the sampling pipe 9 and the connection pipe 11, and a heat insulating material 21 of silicone rubber is wound thereon. In addition, the strip-shaped heating wire 20 is a member that adjusts the flowing current to heat the sampling pipe 9 and the connection pipe 11 to 100° C. or higher, thereby suppressing the adhesion of reaction by-growth in these pipes.

In addition, in the piping main body 19 and the light-transmitting window material 19a of the moisture meter 10, the pipe use heating wire 22 mainly for heating these resistance wires is attached, and it heats it to 100 degreeC or more. In addition, the moisture meter 10 performs adjustment and calibration of its measurement sensitivity in advance according to the temperature of the gas heated to 100° C. or higher by the strip-shaped heating wire 20 and the tube heating wire 22 .

Next, a method of judging the maintenance period of the epitaxial crystal growth apparatus of the present embodiment will be described using FIG. 7 .

First, to describe the process of epitaxial growth on a silicon substrate W using the above-mentioned growth apparatus, the silicon substrate W is transported from the loading lock chamber 3 into the transport chamber 2, and the atmosphere in the transport chamber 2 is replaced with N ₂ and other inert gas, while monitoring the moisture in the atmosphere with the transport system moisture meter 6, and after confirming that the moisture has been sufficiently reduced, the silicon substrate W is transported into the processing chamber 1.

In the processing chamber 1, before processing, it is in the purification state of inert gas such as N ₂ , but after the silicon substrate W sent from the transport chamber 2 is arranged and heated to a predetermined temperature, a predetermined corrosive gas is introduced, Epitaxial growth is performed on the surface of the substrate W. At this time, the rotary pump 12 is driven, and at the same time, the valve of the sampling pipe 9 is opened to adjust the inflow, and a part of the heated corrosive gas supplied to the processing chamber 1 for reaction is constantly introduced into the moisture meter body 10 through the sampling pipe 9 .

The gas to be sampled flows into the tubular unit body 19 in the moisture meter body 10 and is irradiated by the infrared laser light L from the semiconductor laser LD. The infrared laser light L passing through the gas in the tubular unit body 19 is received by the photodetector PD, and the moisture concentration in the gas is monitored according to the intensity of the absorption spectrum obtained from the received amount, and the quantitative analysis of the moisture contained in the gas is performed. Furthermore, the gas flowing into the tubular unit body 19 is discharged to the exhaust system through the connecting pipe 11 and the rotary pump 12 . In addition, the pressure in the processing chamber 1 is constantly monitored by a pressure gauge 7 .

After the epitaxial growth is completed, the inside of the processing chamber 1 is replaced with an inert gas, and the processed silicon substrate W is carried out from the load-lock chamber 4 through the transfer chamber 2 .

The above-mentioned treatment is repeated, and epitaxial growth is carried out sequentially on multiple silicon substrates W. However, as shown in FIG. 7 , the water concentration in the treatment chamber 1 is constantly monitored by the moisture meter 5 used for the treatment at this time, and the process is recorded. In addition, in Fig. 7, the peak value of the water concentration is detected in one film formation process, but the small peak is the water concentration in the actual film formation, and the large peak is when the polysilicon adhered in the treatment chamber is etched with HCl (hydrogen chloride). moisture concentration.

It can also be seen from Figure 7 that each time the number of sheets processed increases, the water concentration gradually decreases. Since the decrease of this moisture is considered to be equivalent to the amount of moisture that actually enters into the processing chamber 1 to supply corrosion and the reaction of particles, etc., according to the change of the moisture concentration (reduction of the moisture concentration), the amount of water that enters into the processing chamber 1 is calculated from the above. The cumulative amount of moisture at the start of the maintenance, and the next maintenance period is determined according to the cumulative amount. That is to say, the transition of the accumulated moisture is estimated from the change of the monitored moisture concentration, and the period as the scheduled cumulative quantity is set as the next maintenance period, and at the same time, when the cumulative moisture calculated from the change of the moisture concentration actually reaches the predetermined Carry out maintenance at the moment of the cumulative amount. In addition, the maximum number of sheets to be treated is set in advance based on other factors (adhesion of by-growths in the piping, etc.), and the above-mentioned maintenance is performed when the previous period is expected to reach the above-mentioned predetermined cumulative amount compared with the maximum number of sheets to be processed, However, when the water concentration is low and the time to reach the predetermined cumulative amount is later than the time to reach the maximum number of processed sheets, maintenance is performed once the maximum number of processed sheets is reached.

In this embodiment, since the maintenance period is determined according to the accumulated moisture amount calculated from the change in moisture concentration, the amount of moisture actually entering the processing chamber 1 can be accurately predicted, and maintenance can be performed at an appropriate time. Therefore, the next maintenance period can be determined according to the actual water intake in each maintenance, and good film-forming treatment can be maintained frequently. At the same time, the maintenance frequency can be reduced and the maintenance period can be extended, which can improve productivity.

In addition, the pressure in the processing chamber 1 is also the same as the moisture concentration. Since the pressure gauge 7 is used for constant monitoring, it is possible to detect the flow state of the gas exhaust system piping (for example, due to the generation of side reactants attached, the blockage of the piping). A more suitable maintenance period can be determined by estimating the maintenance period by considering both the accumulated amount of moisture and the above-mentioned pressure change in consideration of the pressure fluctuation in the processing chamber 1 generated in the process. Furthermore, the next maintenance time can be estimated by comparing the data on the occurrence rate of defective products during manufacturing among the above-mentioned cumulative amount of moisture and the above-mentioned pressure change, and a more suitable maintenance time can be determined.

In addition, since the water concentration and pressure in the processing chamber 1 are constantly monitored, if the change shows a tendency to be abnormal compared to normal, investigation and maintenance of the cause can be directly carried out according to the situation.

In addition, since the above-mentioned laser moisture meter is used as the moisture concentration detection device for processing, the moisture concentration in the processing chamber 1 can be accurately measured even during processing, and the maintenance time can be determined with high accuracy.

Furthermore, the present invention includes the following examples.

In the above embodiments, a vapor phase growth apparatus for performing epitaxial growth was used as a semiconductor manufacturing apparatus, but it can also be applied to other semiconductor manufacturing apparatuses as long as it reacts a corrosive gas in a reaction chamber. For example, a CVD apparatus for forming other thin films on a substrate, a dry etching apparatus for etching a substrate surface using a corrosive gas, etc. may be used.

In addition, in the above-mentioned embodiments, a leaf-type epitaxial growth apparatus is used, but it is not limited to this, and other methods (various batch methods, etc.) may also be used.

C. Moisture monitoring device and semiconductor manufacturing device equipped with the device

Hereinafter, an embodiment of the moisture monitoring device of the present invention and a semiconductor manufacturing device equipped with the device will be described with reference to FIGS. 8 to 10 .

In these figures, reference numeral 1 denotes a processing chamber, 2 denotes a transfer chamber, 3 denotes a delivery load lock chamber, 4 denotes a delivery load lock chamber, and 25 denotes a moisture monitoring device.

FIG. 8 is a diagram showing a state where the semiconductor manufacturing apparatus of the present invention is used, for example, in a leaf-type epitaxial crystal growth apparatus. This epitaxial crystal growth apparatus, as shown in FIG. Substrate transfer system) 2, when the silicon substrate W is sent into these processing chambers 1, the atmosphere is replaced in the closed space inside; it is sent into the load lock chamber 3, and the silicon substrate W before processing is sent into the transfer chamber 2; and sending out of the load lock chamber 4, and taking out the processed silicon substrate W from the transport chamber 2.

Each of the processing chambers 1 is provided with a moisture monitoring device 25 that samples the corrosive gas introduced into the processing chamber 1 and monitors the moisture contained in the corrosive gas.

Furthermore, even in the transport chamber 2, a transport system moisture meter 6 for monitoring moisture in the internal atmosphere is provided. The delivery system moisture meter 6 is, for example, preferably a laser moisture meter similar to the laser moisture meter 10 described below with good accuracy and response speed, or it may be an electrostatic device that absorbs moisture in alumina, a capacitor, etc., and monitors changes in its capacitance. Volumetric moisture meters and moisture meters using mass analysis methods, etc.

In the processing chamber 1, as shown in FIG. 9, gases (SiCl ₂ H ₂ , SiCl ₃ H, HCl, H ₂ , N ₂ , B ₂ H ₆ , PH ₃ , etc.) processing gas introduction pipe 27 is connected to processing gas exhaust pipe 28 in the processing chamber 1, which exhausts corrosive gases and the like to exhaust processing equipment (not shown in the figure) after the reaction is supplied.

The moisture monitoring device 2 is provided with: a sampling pipe 9, one end side of which is equipped with a valve 9a is connected to the sampling processing chamber 1 through the front end side of the processing gas exhaust pipe 28; The moisture contained in the corrosive gas from the processing chamber 1 connected by the variable valve 9b; and the rotary pump 12 are connected to the rear end of the laser moisture meter 10 with a connecting pipe through the variable valve 11a.

A pipe purge conduit 13 for purging the sampling conduit _N2 is connected to the front end side of the sampling pipe 9 through a valve 13a, and a processing gas introduction pipe 27 is connected to the pipe purge conduit 13 through a branch pipe 14 through a valve 14a. In addition, the piping purge conduit 13 is provided with a valve 13b upstream of the connection portion of the branch pipe 14 .

In the laser moisture meter 10, as shown in FIG. 9 and FIG. 10, the inside of the frame 10a is connected to the frame purification conduit 15 for _N2 purification, and at the same time, the other end is connected to the _N2 to discharge the N2. Process gas exhaust pipe 28 is connected to _N2 exhaust conduit 16 .

Furthermore, the rotary pump 12 is connected to a processing gas exhaust pipe 28 through a valve 17a through a sampling exhaust pipe 17 . In addition, the rotary pump 12 is connected to the N ₂ purge conduit 18 used by the gas stabilizer.

As shown in FIG. 10 , the laser moisture meter 10 is provided with a tubular unit body 19 inside the frame 10 a , and one end of the tubular unit body 19 is connected to the sampling pipe 9 and the other end is connected to the connection pipe 11 . Tubular unit body 19 is equipped with translucent window material 19a at both ends, on the outside of one translucent window material 19a, the semi-conductor laser LD that produces infrared laser L (wavelength 1.3～1.55 μm) variable wavelength is oppositely arranged, On the outside of the other translucent window material 19a, a photodetector PD that receives the infrared laser light L transmitted through the tubular unit body 19 and converts the intensity of the received light into an electrical signal is disposed opposite to each other.

A strip-shaped heating wire (pipe heating means, resistance wire) 20 is wound around the sampling pipe 9 and the connecting pipe 11, and a heat insulating material 21 of silicone rubber is wound thereon. In addition, the ribbon-shaped heating wire 20 is connected to a current supply source not shown in the figure. Then, the current flowing through the strip-shaped heating wire 20 is adjusted to heat the sampling pipe 9 and the connection pipe 11 to about 100°C.

In addition, in the piping main body 19 and the translucent window material of the laser moisture meter 10, a unit-use heating wire (unit heating mechanism) 22 mainly for heating these resistance wires is installed and heated to 100°C.

In addition, the laser moisture meter 10 performs adjustment and calibration of its measurement sensitivity in advance according to the temperature of the corrosive gas heated to 100° C. by the strip-shaped hot wire 20 and the tube hot wire 22 .

Next, a moisture monitoring method during epitaxial crystal growth in an embodiment of a semiconductor manufacturing apparatus equipped with the moisture monitoring device of the present invention will be described.

First, the silicon substrate W undergoing epitaxial growth is transported from the transport load lock chamber 3 to the transport chamber 2, and the atmosphere in the transport chamber 2 is replaced with an inert gas such as N ₂ . At this time, the moisture in the atmosphere is monitored by the moisture meter 6 of the transport system, and the silicon substrate W is transported into the processing chamber 1 after confirming that the moisture has been sufficiently reduced.

In the processing chamber 1, before the processing, although the inert gas such as _N2 is used to achieve the purification state, but after the silicon substrate W transported from the transport chamber 2 is heated to a predetermined temperature, the valves 13a, 13b, 14a are closed, and the processing gas is used The introduction pipe 27 introduces a predetermined corrosive gas or the like to perform epitaxial growth on the surface of the silicon substrate W. At this time, the valves 9a and 17a are opened, and the rotary pump 12 is driven at the same time, and while the inflow is adjusted with the variable valves 9b and 11a, the laser moisture meter 10 is constantly introduced to supply the reaction through the sampling pipe 9 in the processing chamber 1. Heated part of corrosive gas.

The sampled corrosive gas flows into the tubular unit body 19 of the laser moisture meter 10 and is irradiated by the infrared laser light L from the semiconductor laser LD. The infrared laser light L transmitted through the corrosive gas in the tubular unit body 19 is received by the photodetector PD, and the moisture contained in the corrosive gas can be quantitatively analyzed based on the intensity of the absorption spectrum obtained from the amount of received light.

The corrosive gas flowing into the tubular unit body 19 is discharged to the processing gas exhaust pipe 28 through the connection pipe 11 , the rotary pump 12 and the sampling exhaust pipe 17 .

In this embodiment, since not only the laser moisture meter 10 is provided, but also the strip-shaped hot wire 20 for heating them is provided in the sampling pipe 9 and the connecting pipe 11, the sampling pipe 9 and the connecting pipe 11 can be heated to 100°C. The high temperature state of about ℃ can suppress the side reaction inside the piping of the corrosive gas heated in the processing chamber 1, and prevent the piping from being clogged by reaction by-growth. Therefore, daily moisture can be monitored in situ.

Moreover, since the laser moisture meter 10 adjusts and corrects its measurement sensitivity in advance according to the temperature of the corrosive gas heated to about 100°C, it is possible to measure moisture with appropriate sensitivity and high precision even in high-temperature corrosive gases. concentration. In addition, adjustment and correction of measurement sensitivity are performed, for example, by arithmetically processing a signal from the photodetector PD in a control unit (not shown) connected to the photodetector PD.

In addition, since the transport chamber 2 is equipped with a transport system moisture meter 6 for monitoring the moisture in the internal closed space in addition to the laser moisture meter 10, when the silicon substrate W is sent into the processing chamber 1 through the transport chamber 2, it is possible to measure and confirm the moisture content of the transport chamber. Moisture in the transport chamber 2 can prevent the moisture in the delivery chamber 2 from flowing into the processing chamber 1 inadvertently.

Furthermore, the present invention includes the following examples.

In the above embodiments, the semiconductor manufacturing apparatus is applied to a vapor phase growth apparatus for epitaxial growth, but it can also be applied to other semiconductor manufacturing apparatuses as long as it reacts a corrosive gas on a substrate in a reaction chamber. For example, it can be applied to a CVD apparatus for forming other thin films on a substrate, a dry etching apparatus for etching a substrate surface using a corrosive gas, and the like.

In addition, in the above-mentioned embodiments, a leaf-type epitaxial growth apparatus is used, but it is not limited to this, and other methods (various batch methods, etc.) may also be used.

In addition, before the treatment, after purging each piping and processing chamber with N ₂ , introduce a corrosive gas as a reaction gas, but it is also possible to purify with HCl (hydrogen chloride) after sufficient N ₂ purging, and then introduce Provides corrosive gases for growth. In this case, the moisture adsorbed on the inner walls of the pipes and the processing chamber is combined with HCl molecules and sent out, thereby reducing the moisture entering the corrosive gas supplied later.

Claims (4)

1. A method for judging the maintenance period of a semiconductor manufacturing device, wherein the maintenance period of a semiconductor manufacturing device in which a corrosive gas treatment is performed in a reaction chamber (1) is judged, wherein when the corrosive gas treatment is performed, A moisture meter (5) connected to the reaction chamber (1) is used to monitor the moisture concentration in the reaction chamber (1), and the maintenance period is determined according to the change of the moisture concentration when the corrosive gas treatment is repeated. 2. The method for judging the maintenance period of a semiconductor manufacturing device according to claim 1, characterized in that, based on the change of the water concentration, the cumulative amount of water entering the reaction chamber (1) since the last maintenance is calculated. amount, and the maintenance period is determined according to the accumulated amount. 3. The method for judging the maintenance period of semiconductor manufacturing equipment according to claim 2, characterized in that, when the corrosive gas treatment is performed, a pressure gauge (7) connected to the reaction chamber (1) is used to monitor The pressure in the reaction chamber (1) is determined according to the pressure change and the accumulated amount of moisture when the corrosive gas treatment is repeated. 4. The method for judging the maintenance period of a semiconductor manufacturing device according to claim 1, wherein the moisture meter (5) is a laser moisture meter, and the moisture meter measures the amount of laser light incident on the reaction chamber (1). Laser absorption spectrum of laser light transmitted through the connected tubular unit body (19).

Images