JP2001257197A - Manufacturing method and manufacturing device for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device which can monitor such a progress and so on of chemical reaction used at a semiconductor manufacturing process in a high precision and can perform at a practical cost. SOLUTION: A manufacturing method for a semiconductor device include a process of performing a process of a wafer 102 by a processing gas which is introduced into a processing chamber, by using a device which is provided with the processing chamber 101, a pump 109 which performs exhausting associated with the processing at the processing chamber, and a flow variable valve 105 for adjusting a flow of exhausting gas flowing through the pump. In the manufacturing method, a mass spectrometry gas analyzer 107 is connected between the pump and the flow variable valve, exhausting gas is analyzed under the condition of a pressure of the exhausting gas which is introduced into the gas analyzer being adjusted in a predetermined range, and process controlling for the wafer processing is performed, based upon the analyzed result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, a wafer is subjected to various processes utilizing a chemical reaction or the like, for example, an etching process, a sputtering process or a CVD process. In these wafer processes, it is important to monitor the progress of the reaction and to perform process control based on the results. In particular, semiconductor devices whose microstructure is progressing with higher integration are required to be highly integrated. For quality and productive manufacturing, there is a growing need for accurate monitoring.

[0003] In wafer processing utilizing a chemical reaction or the like, there is also a problem related to a deposited film generated in a processing chamber. That is, it is difficult to completely evacuate the reaction product accompanying the wafer processing from the processing chamber, and it is inevitable that the reaction product adheres to the inner wall of the processing chamber and the surface of the component to form a deposited film. The main reaction product is, for example, a chlorine-based, bromine-based, boron-based compound or a metal-based compound to be etched in an etching process, or a resist used for masking a portion not to be etched. Is an organic compound. When a deposition film of a reaction product is formed in the processing chamber, dust is generated therefrom. In addition, when the etching process is repeatedly performed, the deposited film gradually becomes thick, and is easily peeled from the inner wall of the processing chamber or the surface of the component to which the deposited film is attached. Then, when peeled, the peeled pieces drop off on the wafer, which causes disconnection, for example. Further, a gas is also generated from the deposited film, and the gas makes the process unstable. For example, the reproducibility of the etching is reduced, and as a result, the yield is reduced. All of these lead to a decrease in productivity and an increase in production cost. Therefore, it is important to monitor the state of the deposited film and to monitor the progress of the cleaning process for removing the deposited film in order to improve production efficiency.

As described above, gas analysis is an effective means for performing monitoring required in various processes without affecting the processes. Many proposals have already been made for this gas analysis. For example, JP-A-8
Japanese Patent No. 3,066,71 discloses that in a selective etching process of a silicon oxide film, the amounts of carbon monofluoride radicals and carbon difluoride radicals generated in plasma by a carbon fluoride-based gas are measured, and the etching conditions are determined from the ratio. It has been proposed to perform high-selective etching by controlling the above. Further, for example, Japanese Patent Application Laid-Open No. 8-222182 describes a method of more accurately and stably forming a wiring film by detecting gas components in a processing chamber more accurately in a sputtering process.
In addition, it has been proposed to monitor gas components in order to inspect a leak in a processing chamber of a reduced pressure processing apparatus used in a CVD process or the like. For example, as described in JP-A-8-45856, a partial pressure of oxygen gas and a partial pressure of nitrogen gas in a processing chamber after evacuation are measured, and a leak (external leak) in the processing chamber is detected from a ratio between the two. An example is how to do this. Further, for example, Japanese Patent Application Laid-Open No. 6-27
As described in Japanese Patent No. 5562, a method using gas analysis for monitoring ashing of a photoresist has been proposed.

The gas analysis for monitoring shown in the above examples is a method using a quadrupole mass spectrometer. The quadrupole mass spectrometer ionizes a gas to be analyzed and obtains a spectrum of a ratio (m / e) between the mass of the ion and the valence of the ion. The operable pressure has an upper limit. That is, if the pressure is too high, the filament that supplies electrons for ionization will burn out. Also, under high pressure, the probability of ionized gas molecules colliding with other gas molecules before reaching the detector increases, the number of ions that can reach the detector decreases, and the correct amount of ions cannot be detected. I will. Regarding this operable upper limit pressure, all of the quadrupole mass spectrometers based on the above-mentioned known techniques are at a level of 10 -3 Pa (Pascal). However, the pressure conditions during the processing in the reaction processing chamber in a general semiconductor device manufacturing process are, for example, about 1 to 2 Pa, and the pressure orders are greatly different.

Therefore, Japanese Patent Application Laid-Open Nos. Hei 8-3066671, Hei 8-222182 and Hei 8-45856 are disclosed.
As described in the above publications, a method is required in which a quadrupole mass spectrometer is placed in a differential exhaust chamber provided separately from the processing chamber, and the inside of the quadrupole mass spectrometer is evacuated and analyzed. In this method, the gas in the processing chamber is introduced into the differential exhaust chamber through the orifice, and the flow rate is limited by the orifice so that the gas flow rate becomes very small. Since the internal pressure is 10 −3 Pa or less, gas analysis can be performed.

In addition to the method using a mass spectrometer as described above, for example, Japanese Patent Application Laid-Open Nos. 1-286307 and 8-
As disclosed in Japanese Patent Publication No. 218186, an example using an emission spectrum analysis method is also known.

[0008]

Many proposals have already been made for using gas analysis for monitoring a reaction process as described above. However, the fact is that monitoring by gas analysis has not been put to practical use in actual production lines. There are various reasons for this. In the case of mass spectrometry,
For example, as described in the section of the prior art in JP-A-8-222182, when differential exhaust is used,
When it is desired to measure the concentration of a trace amount of a gas component such as an impurity gas in a gas sampled from a processing chamber, the gas concentration becomes extremely low after differential evacuation, which makes detection extremely difficult. is there.

There is also a problem that the sampled gas remains due to being adsorbed in the differential exhaust chamber and adversely affects subsequent measurements. For example, water vapor or the like is adsorbed on the surface of stainless steel that is generally used as a material for the differential exhaust chamber, and remains after repeated desorption and adsorption over a long period of time. As a result, it overlaps with the water vapor in the sampled gas, causing an error in the measured concentration value. To avoid this, the stainless steel chamber must be baked periodically, but during that time monitoring is not possible, which makes operation difficult and leads to increased production costs.

Further, it is difficult to reduce the size of a unit combining a differential pumping chamber and a high-vacuum pump for pumping the chamber. In order to use this unit in a general semiconductor device manufacturing apparatus, it is necessary to use a clean room. In many cases, there is an adverse effect due to a space-related problem. In addition, the differential pumping system that requires a high vacuum is expensive and has problems not only in terms of cost but also in that it has poor practical reliability at present.

On the other hand, the emission spectrum analysis method has no pressure-related problem as seen in the above-described mass analysis method. However, in the case of the emission spectrum analysis method, in addition to the emission spectrum analyzer, it is necessary to convert the sampling gas into plasma, so that a plasma conversion apparatus is required. In addition, the emission spectrum analyzer itself is very expensive compared to mass spectrometry, and the plasma conversion apparatus is also expensive. For this reason, the entire apparatus becomes very expensive, and the increase in the size of the entire apparatus is inevitable. As a result, it leaves a problem in its practicality.

Accordingly, an object of the present invention is to enable high-precision monitoring of the progress of a chemical reaction used in a semiconductor production process, at a practical cost, and to perform control based on this high-precision monitoring. Accordingly, it is an object of the present invention to provide a method and an apparatus capable of efficiently producing a semiconductor device having a fine structure of, for example, 0.13 μm or less with high quality.

[0013]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a processing chamber, a pump for evacuating the processing chamber, and a variable pump for adjusting the flow rate of exhaust gas flowing through the pump. A method for manufacturing a semiconductor device, comprising: using a device having a flow valve and performing a process on a wafer with a processing gas introduced into the processing chamber,
A gas analyzer of a mass spectrometer type is connected between the pump and the variable flow valve, and the pressure of the exhaust gas introduced into the gas analyzer is adjusted to a predetermined range by the variable flow valve. The exhaust gas is analyzed by the gas analyzer, and the process control of the wafer processing is performed based on the analysis result.

[0014] The present invention also provides an apparatus having a processing chamber, a pump for performing exhaust in the processing chamber, and a valve for shutting off a flow of exhaust gas flowing from the processing chamber. In a semiconductor device manufacturing method including a process of performing processing on a wafer with a processing gas introduced into the processing chamber, a bypass flow path connecting the processing chamber and the pump is provided in parallel with the valve. Pressure adjusting means for maintaining the pressure in the passage within a predetermined range with the valve closed is provided in the bypass flow path, and a gas analyzer of a mass spectrometer type is further connected to the bypass flow path, The exhaust gas is analyzed by the gas analyzer in a state where the valve is closed, and the process control of the wafer processing is performed based on the analysis result. It is a symptom.

Further, the present invention uses an apparatus having a processing chamber and an exhaust system for exhausting the air in the processing chamber.
A method of manufacturing a semiconductor device, comprising a process of processing a wafer with a processing gas introduced into the processing chamber, wherein the exhaust system has a mass spectrometer operable at a pressure order similar to the pressure of the processing chamber. A gas analyzer of the type is connected, and the pressure of the exhaust gas introduced into the gas analyzer is adjusted to a predetermined range by adjusting the flow rate of the exhaust gas flowing into the exhaust system, and the exhaust gas is exhausted by the gas analyzer. The gas is analyzed, and the process control of the wafer processing is performed based on the analysis result.

According to the present invention, there is provided an apparatus comprising: a processing chamber; a pump for performing exhaust in the processing chamber; and a variable flow valve for adjusting a flow rate of exhaust gas flowing through the pump. In a semiconductor device manufacturing method including a process of performing processing on a wafer by a processing gas introduced into the processing chamber, a mass spectrometer type gas analyzer is connected between the pump and the variable flow valve, By controlling the conductance C of the variable flow valve so as to satisfy the following equation, the exhaust gas introduced into the gas analyzer is adjusted to a predetermined range while the exhaust gas is exhausted by the gas analyzer. The gas is analyzed, and the process control of the wafer processing is performed based on the analysis result.

(Equation 2) Here, Q is the flow rate of the processing gas introduced into the processing chamber, Pc is the pressure in the processing chamber, C is the conductance of the variable flow valve, Pg is the pressure at the branch point to the gas analyzer, Pm is the upper pressure limit desired for gas analyzer operation.

Further, according to the present invention, there is provided each of the above production methods,
The gas analyzer is configured to measure partial pressure values of at least two types of gas components, and preferably uses a ratio of these partial pressure values for process control.

Further, according to the present invention, there is provided each of the above production methods,
The method further includes a process of performing a cleaning process on the deposited film deposited in the processing chamber in the processing of the wafer, and the process control of the cleaning process is preferably performed based on an analysis result of the exhaust gas.

According to the present invention, there is provided an apparatus for manufacturing a semiconductor device, comprising: a processing chamber for introducing a processing gas to perform processing on a wafer; and an exhaust system for performing exhaust in the processing chamber. A gas analyzer of a mass spectrometer type capable of operating at a pressure order similar to the pressure of the processing chamber is connected thereto, and the pressure of exhaust gas introduced into the gas analyzer is adjusted to a predetermined range. Wherein the pressure adjusting means is provided between the processing chamber and the gas analyzer.

[0020]

FIG. 1 schematically shows the structure of an etching apparatus as a semiconductor device manufacturing apparatus according to a first embodiment. The present etching apparatus is used, for example, for etching a metal thin film by a microwave plasma method. For that purpose, a processing chamber 101 is provided,
The wafer 102 carried into the processing chamber 101 is subjected to an etching process. The processing gas 103 is led into the processing chamber 101 while the flow rate of the processing gas 103 is adjusted by the processing gas flow controller 104. The processing gas 103 guided to the processing chamber 101 is turned into plasma by high frequency or microwave introduced into the processing chamber 101, and the plasma is used to perform an etching process on the wafer 102. During the etching process, a chemical reaction occurs in the wafer 102, the inner surface of the processing chamber 101, or the components in the processing chamber 101, and a reaction product gas is generated in the processing chamber 101. The atmosphere flows into the processing chamber 101 from the outside due to leakage or the like. Further, some of the processing gas 103 is not converted into plasma. The reaction product gas, the inflowing outside air, the residual processing gas, and the like are exhausted by an exhaust system including a variable flow valve 105 and a pump 109. Processing room 10
The internal pressure 1 is measured by a vacuum gauge 106, and is adjusted by the introduction amount of the processing gas 103 and the conductance of the variable flow valve 105 so that the value is maintained at a desired pressure, for example, 1 to 2 Pa. These controls are performed by the system controller 11 including control of microwaves and high frequencies.
It is done by 0.

In the present invention, a gas analyzer 107 is provided in such a manufacturing apparatus, and the components of the exhaust gas are measured by the gas analyzer 107. The measured value is monitored by the system controller 110, and based on the result, process control, for example, determination of the end time of the etching process, control of the reaction state, and the like are performed. The gas analyzer 107 includes the variable flow valve 105 and the pump 10
9 is connected. Specifically, the variable flow valve 1
A branch pipe 107p is connected to an exhaust pipe 109p connecting the pump 05 and the pump 109, a gas analyzer 107 is connected to the branch pipe 107p, and a protection valve 108 is provided in the middle of the branch pipe 107p. The gas analyzer 107 is a quadrupole mass spectrometer. This point is the same as the conventional concept described above, except that the operating pressure upper limit is limited to the processing chamber 1.
01 in the same order as the normal pressure during processing. Specifically, for example, the level is 1 Pa. As a quadrupole mass spectrometer capable of operating at such a high pressure, for example, “High-pressure effe
cts in miniature arrays of quadrupole analyzers fo
r residual gas analysis ”, RJ Ferran and S. Boum
sellek, Journal of Vacuum Science and Technology,
A mass spectrometer as reported in P. 1258-1265, A14 (3), 1996 can be used.

According to the present invention, a quadrupole mass spectrometer having an operating pressure limit of the same order as the normal pressure of the processing chamber 101 as described above is used for the gas analyzer 107, and this is used for the variable flow valve 105 and the pump 109. It is one of the features to connect between. With such a configuration, it is possible to perform monitoring by highly accurate gas analysis at a practical cost. This will be described below. The upper limit of the operable pressure of the gas analyzer 107 is 1 Pa level as described above. This is processing chamber 101
Is the same order as the normal pressure during processing of 1 to 2 Pa. However, continued use of the mass spectrometer near its upper operating pressure will greatly reduce its life. Therefore, for example, the actual operating upper limit pressure of the gas analyzer 107 is 1 Pa
Then, on the premise of 1 Pa, it is necessary to provide conditions that can be used at a pressure at which practical durability can be obtained.

For this purpose, the processing chamber 101 and the gas analyzer 1
Means for forming a pressure difference during the period 07 is required. It is not practical to perform this pressure difference in an operating exhaust system using a dedicated exhaust pump as in the above-described prior art because of an increase in the size of the apparatus and an increase in cost. Based on such a problem, the present inventors proceeded with research, and as a result, focused on the fact that the pressure condition of the gas analyzer 107 is slightly different from that of the processing chamber 101, and the processing chamber 101 is always provided. It is possible to provide a desired pressure condition to the gas analyzer 107 only by using the exhaust system. That is, not only the etching processing apparatus according to the present embodiment but also a semiconductor manufacturing apparatus that requires monitoring by gas analysis requires the processing. Since the chamber is generally provided with an exhaust system including a variable flow valve and a pump, the gas analyzer 107 can be used simply by using this exhaust system.
It has been found that a desired pressure condition can be given to a high-pressure mass spectrometer such as the above. Specifically, it is as follows.

The flow rate of the processing gas 103 is Q, the processing chamber 101
Is Pc, the conductance of the variable flow valve 105 is C, and the pressure at the branch point to the gas analyzer 107 is Pg, the following equation (1) is obtained from the definition of the conductance.

(Equation 3) On the other hand, if the upper limit of the pressure desired for the gas analyzer 107 is Pm, it is necessary to satisfy the following expression (2).

(Equation 4) By substituting this into equation (1), the following equation (3) is obtained.

(Equation 5) Therefore, if the parameters on the right side are controlled so that the relationship represented by Expression (3) holds, the gas analyzer 107 can be operated.

Here, the pressure Pc of the processing chamber 101 and the flow rate Q of the processing gas 103 generally affect the result of the etching process, and thus often do not become free parameters. Therefore, usually, the conductance C is controlled so as to satisfy Expression (3). For example, Pc
= 2 Pa, Q = 300 sccm (= 0.51 Pa · cubic m / s), when using the gas analyzer 107 with Pm = 1 Pa, C = 0.51P
What is necessary is just to set the conductance of the variable flow valve 105 so that a · cubic m / s (= 510 liter / s). At this time, it should be noted that the plasma in the processing chamber 101 causes the gas to dissociate and generate,
This means that the flow rate of the gas exhausted through the variable flow valve 105 may increase. Therefore, vacuum gauge 1
It is necessary to control C at any time while monitoring the pressure by 06, and in some cases, it is necessary to set C to a value larger than the value calculated above. That is, when the pressure Pc of the processing chamber 101 changes in a direction to increase from the first assumption, the above equation (3) is changed according to the change.
It is necessary to perform control to change to C so as to satisfy the condition in a feedback manner.

However, even if C is made larger than the effective pumping speed of the pump 109, the effect of lowering Pg cannot be obtained. This is because, in this case, the flow rate of the gas exhausted from the processing chamber 101 is limited not by the conductance C of the variable flow valve 105 but by the effective exhaust speed of the pump 109. Therefore, it is desirable that the pump 109 has a sufficient effective pumping speed. Specifically, under the above conditions, the effective pumping speed is 1.
If a pump of about 5 cubic m / s (= 1500 liter / s), for example, a turbo-molecular pump is used, Q does not increase more than three times in actual processing. Can be adjusted to 1 Pa or less.

As the variable flow valve 105, for example, a valve in which a gas flow path is blocked by a plate or the like can be used.
Since the conductance C in such a variable flow valve 105 is approximately proportional to the cross-sectional area of the flow path, it has substantially the same cross-sectional area as the inlet of the pump 109, and about two-thirds of the cross-sectional area of the flow path If the variable flow rate valve 105 that can be shut off is used, the gas analyzer 107 can be operated.

As described above, the gas analyzer 107 can be operated even during the process and the like, and the process control can be performed more precisely based on the monitoring result. As a result, a high-performance semiconductor device having a finer structure can be manufactured with high production efficiency. Further, the gas analyzer 107 according to the present invention does not require a dedicated exhaust system as described above. Therefore, the size of the analysis system can be reduced, and the cost can be reduced. This is a great advantage in terms of production efficiency and production cost, including the effective use of valuable clean room space.

Here, the gas analyzer 107 for some reason.
It is also conceivable that an unexpected high pressure is suddenly generated in the exhaust system from the vehicle. When such a situation occurs, the protection valve 1
08 is closed to protect the gas analyzer 107 from excessive pressure being applied to the gas analyzer 107. In this case, the gas analyzer 107 is closed at the same time as the protection valve 108 is closed.
It is more preferable to be able to cut off the current supply to the built-in gas ionization filament. By providing such protection means, even if a sudden situation occurs, the gas analyzer 1
07 can be effectively prevented from causing a failure. This is useful for reducing running costs.

Hereinafter, a description will be given of a process of forming a wiring by the above-described etching apparatus with respect to a semiconductor memory as an example shown in FIG. The process flow is as shown in FIG. A device structure as shown in FIG. 2 is formed on the surface of the wafer 102 in FIG. This device structure includes a memory structure including a bit line 201, a word line 202, and a storage electrode 203, on which an interlayer insulating film 204 is formed. An aluminum thin film 205 for wiring is already formed on the upper part, and the upper part is covered with a resist film 206.
Here, the conductive thin film for wiring may be a tungsten thin film, a tantalum thin film, or the like. In the etching process, a predetermined wiring pattern is formed by removing a part of the aluminum thin film 205. For this purpose, openings are provided in the resist film 206 in a pattern corresponding to a predetermined wiring pattern.

To perform the etching process, an etching gas (processing gas 103) is introduced into the processing chamber 101. This etching gas is, for example, a mixed gas of a chlorine gas having a partial pressure of about 1.2 Pa and a boron trichloride gas having a partial pressure of about 1.0 Pa. In addition, for example, a microwave having a frequency of about 2.45 GHz and 800 W is introduced into the processing chamber 101,
Thereby, plasma for etching is generated. At the same time, a high frequency of 2 MHz is applied to the lower surface of the wafer 102 at 60 W to start the etching process (step 301). When the etching process is started, a portion of the aluminum thin film 205 that is not covered with the resist film 206 is removed by etching, and the underlying interlayer insulating film 204 is exposed in the removed portion. The substance (aluminum) removed by etching becomes a gaseous compound and is exhausted from the processing chamber 101 by an exhaust system including a variable flow valve 105 and a pump 109. This etching process is continued until the aluminum thin film 205 is etched to an optimum state. When the etching process is completed, the introduction of the microwave, the application of the high frequency, and the introduction of the etching gas are stopped, and the wafer 102 is unloaded from the processing chamber 101.

In the case of such an etching process, if the time is too short, the etching may be insufficient and the wiring structure may be defective. Even if the processing time is too long, etching is performed even on the underlying interlayer insulating film 204, which may also lead to a defect in the wiring structure. Therefore, it is very important to accurately determine the end time of the etching process for a more stable manufacturing process. In the present invention, the etching state is monitored through the measurement of the gas component of the exhaust gas by the gas analyzer 107 described above, so that the end time of the etching process can be accurately determined.

Specifically, the gas analyzer 107 measures the amount of the aluminum chloride compound generated by the reaction of the aluminum thin film 205 with the processing gas 103 contained in the exhaust gas. The measurement of the aluminum chloride compound by the gas analyzer 107 is performed as the measurement of aluminum chloride ions (step 302). That is, in the gas analyzer 107, the measurement gas is ionized by irradiating the measurement gas with electrons from the filament, and the ions generated thereby are measured. In the case of an aluminum chloride compound, this dissociates. Thus, aluminum chloride ions are generated, and the aluminum chloride ions are measured. There are aluminum chloride ions having a value obtained by dividing the mass by the ionic valence, that is, m / e values of 62 and 64. This is because chlorine atoms have isotopes having mass numbers of 35 and 37. Of these, 35 chlorine atoms have a higher abundance ratio, so that aluminum chloride ion is m
If the signal of / e = 62 is monitored, measurement can be performed with high sensitivity.

Incidentally, there is a possibility that the sensitivity of the gas analyzer 107 may gradually decrease, and it is desirable that this can be corrected. For this purpose, a signal whose level to be measured is substantially constant or known is measured, and the ratio thereof is taken. For example, a constant amount of boron trichloride gas or chlorine gas used in the process is always introduced into the processing chamber 101 if the process conditions are constant. Normally, the conductance of the variable flow valve 105 during the etching process is also substantially constant. Therefore, the signal levels of the boron trichloride gas and the chlorine gas measured by the gas analyzer 107 become substantially constant. Thus, as an example, the ratio with the chlorine gas signal is obtained (step 303). Chlorine gas is measured as a signal of m / e = 35. That is, the ratio of m / e = 35 and m / e = 62 is determined. In the present embodiment, it is assumed that the etching has been properly completed when the value (R) obtained by dividing the signal of m / e = 62 by the signal of m / e = 35 becomes 0.1 or less. Then step 30
In step 4, it is determined that R <0.1, and if the condition is satisfied, the etching is terminated (step 305).

The monitoring of the progress of the reaction using the gas analyzer 107 includes not only the determination of the end time of the etching but also the control of the power of the microwave for plasma formation and the intensity of the high frequency applied to the wafer 102. It can be used to control the whole process. These controls are performed by the system controller 110. By performing such control, the etching process can be performed under more accurate conditions, and therefore, a semiconductor device having a finer structure can be stably manufactured. Further, the production cost can be reduced by improving the yield in the production of semiconductor devices.

The above-described etching process is repeated according to the number of wafers 102 to be processed. When the etching process is repeatedly performed, a reaction product due to the etching reaction adheres to the inner surface of the processing chamber 101, the surface of components in the processing chamber 101, and the like, as in a deposited film 111 illustrated in FIG. In the case of the etching process in the present embodiment, the main components forming the deposited film 111 are:
Boron trichloride gas contained in the processing gas 103 and the processing chamber 10
1 is a boron oxide produced by a reaction with quartz used as a component material. If the deposited film 111 grows to a certain level or more by repeating the etching process, dust and peeled matters tend to be generated from the deposited film 111, and if these adhere to the portion to be etched of the device, it causes etching failure. Therefore, it is necessary to remove or reduce the deposited film 111.

As a method of removing the compound in the deposited film 111, there is a plasma cleaning. Therefore, after the etching process is repeated a specified number of times, or when it is detected by monitoring through the gas analyzer 107 that the deposited film 111 has grown to a certain degree or more, plasma cleaning is performed. For the plasma cleaning, for example, sulfur hexafluoride is used. Specifically, a processing gas for cleaning containing sulfur hexafluoride having a partial pressure of about 1 Pa is supplied to the processing chamber 10.
1 and is converted into a plasma by microwaves of 2.45 GHz and 800 W, for example, to start plasma cleaning (step 306). When the plasma cleaning is started, the boron oxide in the deposited film 111 is decomposed to be gaseous as boron fluoride or the like, and is discharged from the processing chamber 101 by an exhaust system.

In the case of such plasma cleaning, if the processing time is too short, the removal of the deposited film 111 will be insufficient, and the amount of foreign matter generated in the subsequent process will increase. (throughput)
Is reduced. That is, if the cleaning processing time is too short or too long, the production efficiency is reduced. Therefore, it is important to accurately determine the end time of plasma cleaning.

Therefore, the processing state of the plasma cleaning is monitored by measuring a specific component contained in the exhaust gas by the plasma cleaning, specifically, boron fluoride with the gas analyzer 107, thereby completing the plasma cleaning. The timing is determined accurately. The specific contents of the monitoring are as follows.
Since boron has isotopes, boron fluoride ions having m / e of 29 and 30 are detected. Of these, boron fluoride ions are measured by detecting a signal having a large abundance ratio of m / e = 30 (step 307).
In this case as well, the measurement of chlorine ions is performed in the same manner as described above, and the ratio (r) of this to boron fluoride is determined. That is, m / e = 3
The ratio of 5 to m / e = 30 is determined. In the present embodiment, m
It is assumed that the cleaning has been properly completed when the value (r) obtained by dividing the signal of / e = 30 by the signal of m / e = 35 becomes 0.3 or less. Therefore, in step 309, r
A determination of <0.3 is made, and if this is satisfied, the cleaning is terminated (step 310).

In the above embodiment, the processing state is monitored for the etching process and the plasma cleaning process, but the scope of the present invention is not limited to these. For example, it can also be used to check for leaks in the processing chamber 101. In that case, by measuring the amount of water vapor in the exhaust gas from the processing chamber 101, specifically, the increase / decrease of the signal level at m / e = 18, it is possible to determine the presence / absence of leakage of outside air. By accurately determining the leakage of the processing chamber 101 as described above, it is possible to take a countermeasure more quickly, and the processing chamber 1
01 can be prevented from occurring due to the leakage of 01. In addition, different types of processing can be performed in the same processing chamber 10.
In the case where the processing is sequentially performed in step 1, it can also be used to prevent a situation in which a residue in the previous processing adversely affects the subsequent processing. For example, a case where the aluminum thin film is etched after the tungsten thin film is etched will be described as an example. In this case, a gas containing fluorine is used for etching the tungsten thin film, and the fluorine is adsorbed and remains in the processing chamber 101 as a fluoride. It is conceivable that the fluoride has an adverse effect on an etching process of an aluminum thin film that does not use fluorine gas, making it difficult to process a fine device structure. Therefore, a residual gas analysis in the processing chamber 101 is performed between the etching of the tungsten thin film and the etching of the aluminum thin film to grasp the residual state of the fluoride. If the level is at or above the level to be exerted, appropriate treatment such as plasma cleaning using hydrogen chloride gas is taken prior to the etching of the aluminum thin film. The amount of the residual fluoride can be known as the amount of hydrofluoric acid gas in the exhaust gas from the processing chamber 101. That is, the level of the residual fluoride can be grasped by monitoring the signal of m / e = 20.

FIG. 4 shows the configuration of an etching apparatus according to the second embodiment. The difference between the present embodiment and the first embodiment is that the exhaust system of the processing chamber 101 includes a main valve 401 having a fixed flow rate and a large conductance instead of the variable flow valve 105 in the first embodiment. Accordingly, the method of connecting the gas analyzer 107 to the exhaust system is changed accordingly. Specifically, the processing chamber 101
A bypass flow path 402 connecting the pump 109 with the
01, and the gas analyzer 107 is connected to the bypass flow path 402. Further, a flow restrictor 403 is provided in the middle of the bypass flow path 402 as pressure adjusting means, and the pressure applied to the gas analyzer 107 becomes a pressure desired for the operation of the gas analyzer 107 by the fixed flow rate adjustment by the flow restrictor 403. Like that. Thus, the flow restrictor 4
In addition to the configuration in which the pressure adjustment is performed by using the pressure regulator 03, the necessary pressure adjustment can be obtained by appropriately designing the bypass flow path 402. That is, if the bypass flow path 402 is formed in an elongated tubular shape, a pressure gradient that is away from the processing chamber 101 can be generated in the bypass flow path 402. Therefore, by appropriately selecting the mounting position of the gas analyzer 107, It is possible to optimize the pressure of the part. In this case, the bypass flow path 402 itself also serves as a pressure adjusting unit.

In such an etching processing apparatus, when the processing chamber 101 is evacuated prior to the processing in the processing chamber 101, the main valve 401 is opened to evacuate the processing chamber 101.
When performing the process at 01, the main valve 401 is closed, and the gas is exhausted through the bypass flow path 402. In this exhaust, the pressure on the gas analyzer 107 is increased by the fixed flow rate adjustment by the flow rate restrictor 403 as described above.
7 is the desired pressure. The etching process using the etching apparatus according to the present embodiment is the same as that described in the first embodiment, except for the above-described operation method of the exhaust system.

Although the preferred embodiment of the present invention has been described above with reference to an etching apparatus and a process of forming a wiring on an aluminum thin film by using the apparatus, it is needless to say that the present invention can be applied to other apparatuses and processes. It is obvious. As a simple example, for example, a wiring forming process by etching can be applied to an etching process of a thin film such as tungsten or platinum.
In addition to the etching process, the present invention can be applied to, for example, a CVD process or a sputtering process. Generally speaking, the present invention can be applied to any process that can monitor the state of the process by analyzing the components of the gas generated by the process in the process.

Here, the gas analysis system of the present invention is very compact, as can be understood from the above description. As described above, this is a great advantage in terms of production efficiency and production cost, such as effective use of valuable clean room space, but also brings other great advantages. It is easy to incorporate into existing semiconductor production facilities. That is, only a small mounting space is required, and the processing for assembling is also very simple. Therefore, it can be easily incorporated into existing semiconductor production equipment without substantial modification. This can easily improve the performance and productivity of the semiconductor device in the existing semiconductor production equipment.

[0045]

As described above, according to the present invention, it is possible to monitor the progress of a chemical reaction used in a semiconductor production process with high accuracy and at a practical cost. By performing control based on this high-precision monitoring, it becomes possible to produce a semiconductor device having a finer structure with high quality and efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an etching apparatus according to a first embodiment.

FIG. 2 is a partial cross-sectional view of a semiconductor device to be processed by the etching processing apparatus according to the first embodiment.

FIG. 3 is a flowchart of an etching process according to the first embodiment.

FIG. 4 is a schematic configuration diagram of an etching processing apparatus according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Processing chamber 102 Wafer 103 Processing gas 104 Processing gas flow controller 105 Variable flow valve 106 Vacuum gauge 107 Gas analyzer 108 Protective valve 109 Pump 110 System controller 111 Deposition film 401 Main valve 402 Bypass path 403 Flow rate restrictor (pressure regulation) means)

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Manabu Yamashita 6-16-16 Shinmachi, Ome-shi, Tokyo 2 Inside the Device Development Center, Hitachi, Ltd. (72) Toyohide Noritomi 2 Hitachi, Ltd. Device Development Center (72) Inventor Masayuki Kojima 5-2-1, Kamimihoncho, Kodaira-shi, Tokyo F-term in the Hitachi Semiconductor Group 4K029 BD01 CA06 DA02 EA03 EA04 FA09 4K030 DA04 EA11 HA12 JA05 JA09 KA39 KA41 KA45 LA15 5F004 AA15 BB14 BC02 CA09 CB04 DA04 DA11 DA18 DB08 DB09 DB10 EB02 5F045 AA08 AA19 EB06 EG02 GB07 GB15

Claims (7)

[Claims] 1. An apparatus comprising: a processing chamber; a pump for evacuating gas accompanying processing in the processing chamber; and a variable flow valve for adjusting a flow rate of exhaust gas flowing through the pump.
In a semiconductor device manufacturing method including a process of performing processing on a wafer by a processing gas introduced into the processing chamber, a mass spectrometer type gas analyzer is connected between the pump and the variable flow valve, While the pressure of the exhaust gas introduced into the gas analyzer is adjusted to a predetermined range by the variable flow valve, the exhaust gas is analyzed by the gas analyzer, and a wafer processing process is performed based on the analysis result. A method of manufacturing a semiconductor device, wherein the method comprises controlling. 2. A processing chamber, comprising: a processing chamber; a pump for exhausting the processing chamber; and a pump having a valve for shutting off a flow of exhaust gas flowing from the processing chamber. In a method of manufacturing a semiconductor device including a process of performing processing on a wafer by a processing gas introduced into a processing gas, a bypass flow path connecting the processing chamber and the pump is provided in parallel with the valve, and a bypass flow path in the bypass flow path is provided. Pressure adjusting means for maintaining a pressure in a predetermined range in a state where the valve is closed is provided in the bypass flow path, and a gas analyzer of a mass spectrometer type is further connected to the bypass flow path, and the valve is closed. The exhaust gas is analyzed by the gas analyzer in a state where the exhaust gas is analyzed, and the process control of the wafer processing is performed based on the analysis result. Method of manufacturing body device. 3. A process for performing processing on a wafer with a processing gas introduced into the processing chamber using an apparatus having a processing chamber and an exhaust system for performing exhaust in the processing chamber. In the method for manufacturing a semiconductor device, a mass spectrometer-type gas analyzer operable at a pressure order similar to the pressure of the processing chamber is connected to the exhaust system, and a pressure of an exhaust gas introduced into the gas analyzer is connected. Is adjusted to a predetermined range by adjusting the flow rate of the exhaust gas flowing through the exhaust system, the exhaust gas is analyzed by the gas analyzer, and the process control of the wafer processing is performed based on the analysis result. A method for manufacturing a semiconductor device, comprising: 4. An apparatus comprising: a processing chamber; a pump for evacuating gas accompanying processing in the processing chamber; and a variable flow valve for adjusting a flow rate of exhaust gas flowing through the pump.
In a semiconductor device manufacturing method including a process of performing processing on a wafer by a processing gas introduced into the processing chamber, a mass spectrometer type gas analyzer is connected between the pump and the variable flow valve, By controlling the conductance C of the variable flow valve so as to satisfy the following equation, the exhaust gas introduced into the gas analyzer is adjusted to a predetermined range while the exhaust gas is exhausted by the gas analyzer. A method of manufacturing a semiconductor device, comprising: analyzing a gas; and performing a process control of a wafer processing based on the analysis result. (Equation 1) Here, Q is the flow rate of the processing gas introduced into the processing chamber, Pc is the pressure in the processing chamber, C is the conductance of the variable flow valve, Pg is the pressure at the branch point to the gas analyzer, Pm is the upper pressure limit desired for gas analyzer operation. 5. The gas analyzer according to claim 1, wherein the gas analyzer measures partial pressure values of at least two types of gas components, and uses a ratio of these partial pressure values for process control. A method for manufacturing a semiconductor device according to claim 4. 6. A process for performing a cleaning process on a deposited film deposited in a processing chamber in processing a wafer, wherein the process control of the cleaning process is performed based on an analysis result of exhaust gas. Item 1
A method for manufacturing a semiconductor device according to claim 5. 7. A semiconductor device manufacturing apparatus comprising: a processing chamber for introducing a processing gas to perform processing on a wafer; and an exhaust system for performing exhaust in the processing chamber. A gas analyzer of a mass spectrometer type capable of operating at a pressure order similar to the pressure of the processing chamber is connected, and pressure adjustment for adjusting the pressure of exhaust gas introduced into the gas analyzer to a predetermined range. An apparatus for manufacturing a semiconductor device, wherein means is provided between the processing chamber and the gas analyzer.