JP2001185545A - Plasma processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processor which can specify the types of foreign matters in the process chamber of the plasma processor. SOLUTION: Laser beam irradiation optical systems (40, 42, and 44) irradiating laser beams into the process chamber and scattered light detection optical systems (50 and 52) for detecting scattered light from the foreign matters are installed. The types of the foreign matters can be specified based on the difference of the frequency of the laser beam irradiated by the laser beam irradiation optical system and the frequency of scattered light detected by the scattered light detection optical system by using a frequency deviation detector 64.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and, more particularly, to a plasma etching apparatus, a plasma CVD apparatus, an ion implantation apparatus, and a sputtering apparatus used for manufacturing semiconductors and liquid crystal displays. And a plasma processing apparatus.

[0002]

2. Description of the Related Art In a conventional plasma processing apparatus, if a foreign substance is present in a processing chamber, the plasma processing becomes defective, and a defective wafer is generated in a plasma processing such as wear. Therefore, for example, Japanese Patent Application Laid-Open
A foreign object detection device as described in JP-A-289240 or JP-A-11-44654 is used. In the method described in Japanese Patent Application Laid-Open No. 9-289240, the presence of a foreign substance is detected when the intensity of transmitted light from a light source decreases.
In the method described in Japanese Patent Application Laid-Open No. 4 (1999) -1999, the presence of a foreign substance is detected by an increase in the intensity of scattered light generated by irradiating the foreign substance with light.

[0003]

However, the foreign object detection methods described in JP-A-9-289240 and JP-A-11-44654 detect only the presence or absence of foreign matter. Because
There was a problem that it was not possible to identify what kind of foreign matter was present.

An object of the present invention is to provide a plasma processing apparatus capable of specifying the type of foreign matter in a processing chamber of the plasma processing apparatus.

[0005]

(1) In order to achieve the above object, the present invention provides a plasma processing apparatus having a foreign substance monitoring device for irradiating light into a processing chamber and detecting foreign substances in the processing chamber. The foreign matter monitoring device includes: a laser light irradiation optical system that irradiates the processing chamber with laser light; a scattered light detection optical system that detects scattered light from the foreign matter; According to another aspect of the invention, there is provided a foreign matter specifying unit for specifying the type of the foreign matter based on a difference between the frequency and the frequency of the scattered light detected by the scattered light detection optical system. With this configuration, the type of foreign matter in the processing chamber of the plasma processing apparatus can be specified.

(2) In the above (1), preferably,
The laser light irradiation optical system includes a position variable mechanism that can change the irradiation position of the laser light, irradiates the laser light to the maintenance component in the processing chamber, and detects foreign matter based on scattered light from the maintenance component. It is designed to identify the source of the occurrence. With this configuration, it is possible to identify the source of foreign matter in the processing chamber of the plasma processing apparatus.

(3) In the above (2), preferably,
According to another aspect of the invention, there is provided a service life calculating means for calculating the service life of the maintenance component based on the scattered light from the maintenance component. With this configuration, the life of the maintenance component can be calculated.

(4) In the above (1), preferably,
The laser light irradiation optical system irradiates the laser light converged into the processing chamber. With such a configuration, the influence of foreign matter floating in the processing chamber can be reduced, and the accuracy of foreign matter detection can be improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a plasma processing apparatus according to an embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, a plasma CVD apparatus will be described as an example of a plasma processing apparatus. FIG.
1 is a system configuration diagram illustrating a configuration of a plasma processing apparatus according to an embodiment of the present invention.

The reaction chamber 10 is also a processing chamber for performing plasma processing, and constitutes a vacuum chamber. Reaction chamber 10
Inside, a processing object 14 such as a wafer which is attracted by the electrostatic chuck 12 is held. The electrostatic chuck cover 16 is arranged so that the metal surface of the electrostatic chuck 12 is not exposed to the plasma 20.

The ceiling of the reaction chamber 10 is provided with a microwave transmitting window 22. Microwave 24 enters from outside through microwave transmission window 22. Further, a gas nozzle ring 26 is provided inside the reaction chamber 10, and a processing gas is uniformly supplied from the gas nozzle 28 into the reaction chamber 10. The microwave 24 entering from the microwave transmission window 22 and E by a permanent magnet (not shown)
Utilizing CR resonance, high-energy electrons are generated, and the processing gas supplied from the gas nozzle 28 is dissociated and ionized to generate the plasma 20. Depending on the processing apparatus, the electrostatic chuck 16 or the electrostatic chuck 16 may be used.
In some cases, a high frequency is applied from the high frequency power supply 30 to the built-in buried electrode therein to generate a higher density plasma. On the side wall of the reaction chamber 10, a plurality of quartz monitoring windows 32 for observing the state of plasma are arranged.

Next, an optical system of a foreign matter detecting device for detecting foreign matter in the reaction chamber 10 will be described. The optical system of the foreign matter detection device includes a laser light irradiation optical system and a scattered light detection optical system. The laser light irradiation optical system includes a laser oscillator 40, a beam shaping optical system 42, and a zoom lens 44. The beam shape of the laser light emitted from the laser oscillator 40 is shaped by the beam shaping optical system 42. The laser light of the parallel light flux shaped by the beam shaping optical system 42 is converged by the zoom lens 44, passes through the laser light transmission window 34, and is irradiated onto the processing target 14. Since the zoom lens 44 can change the focal length, the zoom lens 44
The convergence position of the converged laser light can also be changed. The laser light irradiation optical system composed of the laser oscillator 40, the beam shaping optical system 42, and the zoom lens 44 can be integrally moved up and down in the illustrated Z axis direction, and can be moved in the θ direction around the Z axis. Can be rotated. Therefore, by moving the laser light irradiation optical system in the Z axis direction and the θ direction, the irradiation position of the laser light can be moved to an arbitrary position on the surface above the processing target 14. That is, the laser light irradiation optical system can scan the processing target 14 with the converged laser light. Also, by moving the laser light irradiation optical system in the Z axis direction and the θ direction,
The irradiation position of the laser beam can also be applied to the reaction chamber 10 formed of an aluminum chamber, the electrostatic chuck cover 16, the gas nozzle ring 26, and the gas nozzle 28. The laser light irradiation optical system includes a half mirror 46.
And a monitor optical system including a light-receiving unit 48. A part of the laser light emitted from the laser oscillator 40 is split by the half mirror 46, received by the light receiving unit 48, and converted into an electric signal. The monitor optical system can also be moved in the Z axis direction and the θ direction integrally with the laser light irradiation optical system.

The scattered light detection optical system includes a condenser lens 50,
And a light receiving unit 52. When the laser light irradiated by the laser light irradiation optical system is irradiated on a foreign material or the like, the laser light is scattered by the foreign material or the like. The scattered light passes through the laser light transmission window 36, is collected by the condenser lens 50, is received by the light receiving unit 48, and is converted into an electric signal. The scattered light detection optical system is disposed so as to have a predetermined angle θ1 with respect to the laser light irradiation optical system, and when the laser light irradiation optical system is moved in the Z axis direction and the θ direction, the predetermined angle θ1 is set. Moved while holding.
With such a configuration, the scattered light detection optical system is configured to detect Raman scattered light scattered by a foreign substance or the like.

Next, the system configuration of the foreign matter detecting device will be described. This system comprises a signal amplifier 60,
It comprises a reflected light intensity detector 62, a frequency deviation detector 64, a comparison calculator 66, a database 68, a maintenance component index life calculation unit 70, a host CPU 72, and a display unit 74. Light receiving unit 48 and light receiving unit 52
Are amplified by the signal amplifier 60, respectively.

The incident / reflected light intensity detector 62 is
(Iout / Iin) of the intensity Iin of the incident light detected by the light receiving unit 8 and the intensity Iout of the scattered light detected by the light receiving unit 52.
Is calculated. By the laser irradiation optical system, for example, when scanning over the processing target 14, the more the number of foreign substances on the processing target 14, the more the irradiated laser light,
Due to scattering, the scattered light intensity Iout detected by the light receiving unit 52 increases. Therefore, the number of foreign substances can be measured by the ratio (Iout / Iin) between the incident light intensity Iin and the scattered light intensity Iout.

The frequency shift detector 64 is connected to the light receiving section 4.
8 and the light receiving unit 5
Difference Δν of the frequency νout of the scattered light detected by
(= Νout−νin) is calculated. In Raman scattering, the difference Δ between the incident light frequency νin and the scattered light frequency νout
ν differs depending on the element to be scattered. Therefore, the type of the foreign matter can be specified by obtaining the difference Δν between the frequency νin of the incident light and the frequency νout of the scattered light by the frequency shift detector 64.

The comparison calculator 66 calculates the ratio (Iout / Iin) of the incident light intensity Iin and the scattered light intensity Iout detected by the incident / reflected light intensity detector 62 and the incident light detected by the frequency shift detector 64. By comparing the difference Δν between the frequency νin and the frequency νout of the scattered light with the data stored in the database 68, the type of foreign matter and the degree are calculated.

The maintenance life calculating part 70 of the maintenance part
Based on the type and the number of foreign substances obtained by the comparison arithmetic unit 66, which of the maintenance parts generates the foreign substances and the life of the maintenance parts are calculated. In the plasma CVD apparatus shown in FIG. 1, a maintenance component exposed to the plasma 20 in the reaction chamber 10 is sputtered by the plasma. Here, as the maintenance parts, for example, the reaction chamber 10, the electrostatic chuck cover 16, the gas nozzle ring 26, and the gas nozzle 28 are raised. The reaction chamber 10 is made of aluminum containing magnesium (Al505).
2), irradiation of plasma causes Al 505
Since the thin film of quartz or the like attached to the surface of No. 2 is damaged and the metal surface is exposed to the plasma, a large amount of aluminum (Al) and a small amount of magnesium (Mg) as foreign substances
And copper (Cu). Further, the electrostatic chuck cover 16, the gas nozzle ring 26, the gas nozzle 28
Emits alumina (Al ₂ O ₃ ) because it is made of alumina. The relationship between these maintenance parts and the types of elements to be released is stored in the database 68. Therefore, when the type of the foreign matter obtained by the comparison arithmetic unit 66 is aluminum (Al), it is possible to use the data of the database 68 to determine that the aluminum chamber constituting the reaction chamber 10 is a foreign matter generation source. it can.
If the type of the foreign matter obtained by the comparison operation unit 66 is alumina (Al ₂ O ₃ ), the database 6
Using the data of No. 8, it is determined that the electrostatic chuck cover 16, the gas nozzle ring 26, and the gas nozzle 28 are sources of foreign matter. Further, the electrostatic chuck cover 1
6, the gas nozzle ring 26, and the gas nozzle 28 are foreign matter generating sources, laser light is individually applied to the electrostatic chuck cover 16, the gas nozzle ring 26, and the gas nozzle 28 using a laser irradiation optical system. Irradiation, the scattered light at that time is detected by the signal amplifier 60, the incident / reflected light intensity detector 62, and the frequency shift detector 64 using the electrostatic chuck cover 16, the gas nozzle ring 26, and the gas nozzle 28. The source of foreign matter can be further determined depending on which component has a large amount of detected alumina. That is, for example, the electrostatic chuck cover 16
When the amount of alumina detected on the upper surface of the processing target 14 is large because the amount of alumina released from the surface is large, the amount of alumina as a foreign substance on the surface of the electrostatic chuck cover 16 is also large, so that static When the amount of alumina as a foreign substance on the surface of the electric chuck cover 16 is large, it can be determined that the amount of alumina released from the electrostatic chuck cover 16 is large.

Next, a method of calculating the service life of the maintenance component in the maintenance component index life calculation unit 70 will be described with reference to FIG. FIG. 2 is an explanatory diagram of the correlation between the usage time of the maintenance component used for calculating the service life of the maintenance component and the amount of foreign matter generated by the maintenance component index life calculation unit 70.

In FIG. 2, the horizontal axis indicates the processing time (use time) in the plasma CVD apparatus, and the vertical axis indicates the amount of alumina as a foreign substance released. Also,
A in the figure shows the change over time of the amount of alumina released from the gas nozzle 28, and B in the figure shows the electrostatic chuck cover 1.
6 shows the change over time of the amount of alumina released from No. 6, and C in the figure shows the change over time of the amount of released alumina from the gas nozzle ring 26. As is apparent from the figure, for example, the amount of alumina released from the gas nozzle 28 gradually increases with the elapse of the processing time (use time) in the plasma CVD apparatus, and the amount of alumina increases rapidly after a certain time TA. I do. Regarding the electrostatic chuck cover 16 and the gas nozzle ring 26, the plasma C
The amount gradually increases as the processing time (use time) in the VD apparatus elapses, and when the time exceeds a certain time TB, TC, the amount of release increases rapidly. If the amount of emitted foreign substances is rapidly increased, an object to be processed such as a wafer is contaminated with metal. At such a time, it is determined that it is time to replace a maintenance part. Specifically, the maintenance life calculation part 70 of the maintenance part determines that the life is reached when the amount of released alumina exceeds a predetermined value V1, for example.
When the maintenance parts need to be replaced, the life is calculated. Needless to say, at this time, the reference alumina emission limit level (the level corresponding to V1 in the figure) for each of the gas nozzle 28, the electrostatic chuck cover 16, and the gas nozzle ring 26 is individually set. Is also good. Further, it is also possible to monitor the time change of the alumina release amount, detect that the release amount has increased rapidly, and calculate the life of the maintenance component. Although the above description is about maintenance parts using alumina, the life can be similarly calculated for the aluminum reaction chamber 10.

Information on the identification of the maintenance component causing the generation of the foreign matter and the life thereof is transmitted to the host CPU 72. The host CPU 72 collectively manages the production state of the plasma CVD apparatus, displays information on the maintenance parts and their life on the display unit 74,
It is transmitted to the user as maintenance information. The user
The maintenance part is replaced based on the maintenance information.

As maintenance parts in the reaction chamber 10, there are a number of gas nozzle rings 26, gas nozzles 28, electrostatic chuck covers 14, and the like. The gas nozzle 26 has a throttle formed at the base to uniformly flow into the plasma 20, and is usually composed of more than ten gas nozzles. Depending on the processing conditions, the nozzles may be arranged up and down, and a large number of parts are to be maintained. Since these maintenance parts are numerous and the cost of one maintenance part is high, the maintenance work requires a lot of time and a lot of cost. On the other hand, in the present embodiment, since the number of generated foreign substances and the location of the generated foreign substances can be specified, the maintenance operation can be easily performed.

As described above, according to the present embodiment, it is possible to specify the type of foreign matter in the processing chamber of the plasma processing apparatus. Further, it is possible to specify the site where the foreign matter is generated. Further, the life of the maintenance component can be calculated from the amount of the foreign matter generated, and the maintenance operation can be easily performed. This makes it possible to optimize the replacement cycle of the maintenance parts, minimize the reduction in the operation rate of the maintenance equipment, and provide a highly productive system. Further, it is possible to minimize the generation of a defective wafer due to a sudden increase in foreign substances due to a sudden discharge in the vacuum chamber. Furthermore, since the laser light irradiation optical system uses a zoom lens to narrow down the laser light and irradiates the foreign matter, the foreign matter on the surface of the target object can be accurately detected without being affected by the foreign matter floating in the reaction chamber. Can be detected.

Next, the configuration of a plasma processing apparatus according to a second embodiment of the present invention will be described with reference to FIG.
In the present embodiment, as the plasma processing apparatus, the plasma C
This will be described using a VD device as an example. The same reference numerals as those in FIG. 1 indicate the same parts. FIG. 3 is a system configuration diagram showing the configuration of the plasma processing apparatus according to the second embodiment of the present invention.

Here, differences from the plasma processing apparatus shown in FIG. 1 will be mainly described. Plasma source is reaction chamber 1
There is an introduction port having a microwave transmission window 22A for microwaves on the side wall of 0A. Microwave is reaction chamber 10A
A permanent magnet 23 having a magnetic field strength that causes ECR resonance is disposed at a microwave introduction port introduced from two or more locations on the circumference of the circle. The high-energy electrons generated by the ECR resonance are released into the vacuum chamber along the lines of magnetic force of the permanent magnets 23, dissociate and ionize the processing gas, and form an interlayer insulating film and the like on the surface of the wafer 14 by a chemical reaction. A permanent magnet 25 for generating a cusp magnetic field for confining plasma is disposed on a side wall and a top plate of the reaction chamber 10A. To generate high-density plasma, a high frequency power is applied from a high frequency power supply 30 through a high frequency introduction rod 11 for applying a high frequency to the electrostatic chuck 12. An insulator 13 made of Teflon or the like is provided around the high frequency introduction rod 11.
Are arranged, and the high frequency is efficiently transmitted to the electrostatic chuck 12 or the high frequency electrode built in the electrostatic chuck 12. An earth shield 15 is arranged outside the above, and suppresses plasma generation at unnecessary parts.

The optical system of the foreign matter detecting device for detecting foreign matter in the reaction chamber 10A comprises a laser light irradiation optical system and a scattered light detecting optical system, as in FIG. The laser light irradiation optical system includes a laser oscillator 40, a beam shaping optical system 42, and a zoom lens 44.
The scattered light detection optical system includes a condenser lens 50 and a light receiving unit 52.

Next, the system of the foreign matter detecting device comprises a signal amplifier 60 and an incident / reflected light intensity detector 6 as in FIG.
2, a frequency deviation detector 64, a comparison operation unit 66, a database 68, and a maintenance part index life calculation unit 7
0, a host CPU 72, and a display unit 74. The configuration and operation of these optical system and detection system are the same as those shown in FIG.

As described above, according to the present embodiment, it is possible to specify the type of foreign matter in the processing chamber of the plasma processing apparatus, as in the embodiment shown in FIG.

Next, the configuration of a plasma processing apparatus according to a third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an ion implantation apparatus will be described as an example of a plasma processing apparatus. The same reference numerals as those in FIG. 1 indicate the same parts. FIG. 4 is a system configuration diagram showing a configuration of a plasma processing apparatus according to a third embodiment of the present invention, and FIG. 5 is a front view of a main part of FIG.

The ion beam extracted from the ion source 100 is used to select a desired beam type by a mass analyzer 102, form a predetermined beam shape, and transfer the ion beam to a wafer 120 or the like held in an end station 110. An injection process is performed. Note that a Q lens or the like can be used instead of the mass analyzer 102. In the end station 110 formed by the vacuum chamber, the wafer 120 holds a wafer holder 134 on a rotating disk 132 rotated by a rotating motor 130.
Fixed and rotated at high speed.

As shown in FIG. 5, the rotating disk 132 is reciprocated in the θ direction by the rotation about the rotating shaft 136 and the scanning mechanism in the scan box 138.
The ion beam is uniformly irradiated on the wafer 120. As shown in FIG.
A protective plate 140 such as a silicon plate is usually disposed on the surface 2 to suppress metal sputtering caused by beam irradiation.

Main maintenance parts include a wafer holder 134 and a silicon plate 140. Since the high energy density ion beam is irradiated during the ion implantation, the wafer holder 134 and the silicon plate 140 may be broken due to thermal expansion. Due to the cracks, foreign substances such as Si may be rapidly generated, and the quality of the processed wafer may be significantly reduced. In the case of high-dose ion implantation typified by SIMOX, the processing time is about three hours, and about ten or more wafers are simultaneously processed at one time. For this reason, damage due to failure of maintenance parts such as the wafer holder 134 and the silicon plate 140 is very large.

The optical system of the foreign matter detecting device for detecting foreign matter in the reaction chamber 10A includes a laser light irradiation optical system and a scattered light detecting optical system, as in FIG. The laser light irradiation optical system includes a laser oscillator 40, a beam shaping optical system 42, and a zoom lens 44,
The laser beam passes through the laser beam transmitting window 34 and
Irradiation on 20 mag. The scattered light detection optical system includes a condenser lens 50 and a light receiving unit 52, and the scattered light is detected by transmitting through the laser light transmission window 36.

Next, as in FIG. 1, the system of the foreign matter detecting device includes a signal amplifier 60 and an incident / reflected light intensity detector 6.
2, a frequency deviation detector 64, a comparison operation unit 66, a database 68, and a maintenance part index life calculation unit 7
0, a host CPU 72, and a display unit 74. The configuration and operation of these optical system and detection system are the same as those shown in FIG.

As described above, according to the present embodiment, it is possible to specify the type of foreign matter in the processing chamber of the plasma processing apparatus, as in the embodiment shown in FIG.

The plasma processing apparatus according to the present invention
The present invention can be applied to a sputtering device, an ion milling device, and the like.

[0037]

According to the present invention, the type of foreign matter in the processing chamber of the plasma processing apparatus can be specified.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a configuration of a plasma processing apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a correlation between a use time of a maintenance component used for calculating a life of the maintenance component and an amount of foreign matter generated by a maintenance component index life calculation unit 70;

FIG. 3 is a system configuration diagram showing a configuration of a plasma processing apparatus according to a second embodiment of the present invention.

FIG. 4 is a system configuration diagram showing a configuration of a plasma processing apparatus according to a third embodiment of the present invention.

FIG. 5 is a front view of a main part of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Reaction chamber 12 ... Electrostatic chuck 14 ... Processing object 16 ... Electrostatic chuck cover 20 ... Plasma 26 ... Gas nozzle ring 28 ... Gas nozzle 34, 36 ... Laser light transmission window 40 ... Laser oscillator 42 ... Beam shaping optical system 44 ... Zoom lenses 48, 52 ... Light receiving unit 50 ... Condenser lens 60 ... Signal amplifier 62 ... Incident / reflected light intensity detector 64 ... Frequency deviation detector 66 ... Comparison calculator 68 ... Database 70 ... Indexing and life calculation of maintenance parts Unit 72 Host CPU 74 Indicator 100 Ion source 102 Mass spectrometer 110 End station 120 Wafer 132 Rotary disk 134 Wafer holder 140 Silicon plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G01N 21/94 G01N 21/94 5F004 H01L 21/203 H01L 21/203 S 5F045 21/3065 H05H 1/00 A 5F103 H05H 1/00 1/46 C 1/46 H01L 21/302 E (72) Inventor Masakazu Hoshino 502 Kandachi-cho, Tsuchiura-shi, Ibaraki F-term in Machine Research Laboratory, Hitachi, Ltd. F-term (reference) 2G043 AA01 CA07 DA08 EA03 FA01 GA02 GA04 GA08 GB19 GB21 HA01 HA09 LA01 2G051 AA90 AB01 BA10 BC05 CB05 EA12 EA14 4K029 CA05 CA10 DA01 DA03 JA01 4K030 FA01 FA02 GA02 HA17 KA09 KA30 KA39 KA49 4K057 DA01 DA20 DJ01 DJ07 DN01 5F004 AA14 AB14A14 AB14A14 A14 CB02 CB09 5F045 AA08 BB15 DP03 EF02 GB10 GB16 5F103 AA08 BB60 NN07 RR10

Claims (4)

[Claims] 1. A plasma processing apparatus having a foreign matter monitoring device for irradiating light into a processing chamber to detect foreign matter in the processing chamber, wherein the foreign matter monitoring device is a laser light irradiating optical system for irradiating the processing chamber with laser light. System, a scattered light detection optical system for detecting scattered light from foreign matter, a frequency of laser light emitted by the laser light irradiation optical system, and a frequency of scattered light detected by the scattered light detection optical system A plasma processing apparatus comprising: a foreign matter identification unit that identifies the type of the foreign matter based on the difference between 2. The plasma processing apparatus according to claim 1, wherein the laser light irradiation optical system has a position variable mechanism that can change the irradiation position of the laser light, and emits the laser light to a maintenance part in the processing chamber. A plasma processing apparatus that irradiates and specifies a source of foreign matter based on scattered light from a maintenance component. 3. The plasma processing apparatus according to claim 2, further comprising a life calculating means for calculating a life of the maintenance component based on scattered light from the maintenance component. 4. The plasma processing apparatus according to claim 1, wherein the laser light irradiation optical system irradiates the laser light converged into the processing chamber.