JP4078043B2 - Method and apparatus for detecting floating foreign matter in plasma processing apparatus and semiconductor device processing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention detects fine particles (foreign matter) floating in a processing chamber of a semiconductor device processing apparatus that forms a desired thin film, circuit pattern, or the like on a semiconductor substrate using plasma such as etching, sputtering, or CVD. The present invention relates to a method, an apparatus thereof, and an apparatus for processing a semiconductor device having a function of measuring, in real time, a foreign substance generated in a processing chamber in a process of forming a thin film, a circuit pattern, or the like by plasma processing technology.
[0002]
[Prior art]
Starting with an etching apparatus, a process using plasma is widely applied to a semiconductor device processing (manufacturing) process and a liquid crystal display substrate processing (manufacturing) process.
[0003]
As an example of a processing apparatus using plasma, there is a parallel plate type plasma etching apparatus shown in FIG. As shown in FIG. 25, this type of apparatus modulates the output voltage of the power amplifier 84 by a high frequency signal from a signal generator 83, distributes the high frequency voltage by a distributor 85, and arranges them in parallel in the processing chamber. For example, a semiconductor substrate (wafer) as an object to be processed with the active species is generated between the upper electrode 81 and the lower electrode 82, and plasma 71 is generated from the etching gas by discharge between the electrodes 81 and 82. W is etched.
[0004]
For example, a frequency of about 400 kHz is used as the high frequency signal. In the etching process, the progress of the etching is monitored, the end point thereof is determined as accurately as possible, and the etching process is performed for a predetermined pattern shape and depth. When the end point is detected, the output of the power amplifier is stopped and the semiconductor wafer is discharged from the processing chamber.
[0005]
In the plasma etching apparatus, it is known that a reaction product generated by an etching reaction by plasma processing is deposited on the wall surface or electrode of the plasma processing chamber and peels off as time passes to become floating foreign matters. . This floating foreign substance falls on the wafer and becomes a foreign substance attached at the moment when the etching process is finished and the plasma discharge is stopped, causing a circuit characteristic defect and a pattern appearance defect. Ultimately, this causes a decrease in yield and a decrease in device reliability.
[0006]
A number of devices for inspecting foreign matter adhering to the wafer surface have been reported and put into practical use. However, these devices are used to inspect the wafer once extracted from the plasma processing apparatus, and it has been found that many foreign matters are generated. At that time, the processing of other wafers has already progressed, and there is a problem of a decrease in yield due to a large number of defects. Further, in the evaluation after the processing, the distribution of the generation of foreign matters in the processing chamber and the change with time are not known.
[0007]
Accordingly, there is a demand in the fields of semiconductor manufacturing, liquid crystal manufacturing, and the like for techniques for real-time monitoring of the contamination status in the processing chamber in-situ.
[0008]
The size of foreign matter floating in the processing chamber is in the range of submicron to several hundred μm. The minimum line width is 0.25 to 0.18 [mu] m and is continuously miniaturized, and the size of foreign matter to be detected is also required to be on the order of submicrons.
[0009]
As conventional techniques for monitoring foreign matter floating in a processing chamber (vacuum processing chamber) such as a plasma processing chamber, Japanese Patent Laid-Open Nos. 57-118630 (prior art 1) and Japanese Patent Laid-Open No. 3-25355 (prior art 2). ), JP-A-3-147317 (Prior Art 3), JP-A-6-82358 (Prior Art 4), JP-A-6-124902 (Prior Art 5), JP 10-213539 (Prior Art 6). ) Is disclosed.
[0010]
The prior art 1 includes means for irradiating the reaction space with parallel light having a spectrum different from the spectrum of the self-emission light in the reaction space, and scattering from fine particles generated in the reaction space upon receiving the parallel light irradiation. A vapor deposition apparatus provided with a means for detecting light is disclosed.
[0011]
Further, in the above conventional technique 2, in a fine particle measuring apparatus that measures fine particles adhering to the surface of a semiconductor device substrate and floating fine particles using scattering by laser light, the wavelength is the same and the mutual position is low. A laser beam phase modulation unit that generates two laser beams modulated at a predetermined frequency having a phase difference, and an optical system that intersects the two laser beams in a space including the fine particles to be measured; A light detection unit that receives light scattered by the fine particles to be measured in the intersected region of the two laser beams and converts the light into an electric signal, and the laser beam phase in the electric signal by the scattered light A fine particle measuring apparatus comprising: a signal processing unit that extracts a signal component having the same or twice the frequency as the phase modulation signal in the modulation unit and a phase difference from the phase modulation signal that is constant in time. It is shown.
[0012]
The prior art 3 includes a step of generating light scattered in the reaction container by scanning irradiation with coherent light, and a step of detecting light scattered in the reaction container. A technique for measuring the contamination state in the reaction vessel by analyzing the scattered light is described.
[0013]
The prior art 4 includes laser means for generating laser light, scanner means for scanning a region in a reaction chamber of a plasma processing tool containing particles to be observed with the laser light, and particles in the area. A particle detector is described having a video camera for generating a video signal of scattered laser light and means for processing and displaying an image of the video signal.
[0014]
Further, the conventional technique 5 includes a camera device for observing a plasma generation region in the plasma processing chamber, a data processing unit for processing images obtained by the camera device to obtain target information, and the data processing unit. A plasma processing apparatus comprising: a control unit that controls at least one of exhaust means, process gas introduction means, high-frequency voltage application means, and purge gas introduction means so as to reduce particles based on the information obtained in Are listed.
[0015]
The prior art 6 also includes a light transmitter for transmitting a light beam that irradiates across the measurement volume, a light detector and scattered light from the measurement volume and condensing the light to the light detector. And a detector configured to generate a signal representative of the intensity of light directed to the photodetector and to analyze the signal from the photodetector. Connected to a pulse detector for detecting a pulse in the signal from the light detector, and corresponding to the particle by the particle associated with multiple irradiations of the beam while the particle moves through the measurement volume. A particulate sensor is described that includes signal processing means including an event detector that identifies a series of pulses due to scattered light.
[0016]
Each of the above-described conventional techniques irradiates laser light from an observation window provided on the side surface of the processing apparatus, and from an observation window different from the laser irradiation observation window provided on the opposite side surface or other side surface, Laser forward scattered light and side scattered light are detected. Therefore, in the method for detecting the forward scattered light and the side scattered light, the irradiation optical system and the detection optical system are formed by different units, and two observation windows for attaching them are necessary. Axis adjustment and the like must also be performed by the irradiation / detection optical system, and handling is troublesome.
[0017]
Usually, an observation window on the side of a processing chamber such as a plasma processing chamber is provided in most models for monitoring plasma emission, etc., but only one observation window is provided. Not a few. Therefore, there is a problem that the conventional method that requires two observation windows cannot be applied to a manufacturing apparatus having a processing chamber that has only one observation window.
[0018]
Furthermore, in the conventional method for detecting forward scattered light and side scattered light, the irradiation beam irradiated to the processing chamber is rotated and scanned to observe the occurrence of foreign matter on the entire surface of the object to be processed such as a wafer. Requires a large number of observation windows and detection optical systems, resulting in a significant cost increase, and it is actually very difficult to provide a large number of observation windows and detection optical systems due to space factor limitations. Is expected.
[0019]
In addition, all of the above-described conventional techniques are for observing a partial region on the wafer using a fixed laser beam, and it is difficult to measure floating foreign substances in the plasma over the entire surface of the wafer.
[0020]
A semiconductor manufacturing method and apparatus having a function of in-situ measurement of foreign matters floating in the plasma processing chamber over the entire surface of the wafer have also been proposed, for example, Japanese Patent Laid-Open No. 9-24359 (prior art 7).
[0021]
In the conventional technique 7, laser light is irradiated in the vertical direction, horizontal direction, or vertical and horizontal directions in the processing chamber, the laser light scattered by the particles in the processing chamber is detected, and the processing chamber is determined from the intensity of the detected laser light. There is described a particle monitoring method characterized by monitoring particles in a real time.
[0022]
However, in any of these methods, the laser illumination optical system and the scattered light detection optical system are separated. Therefore, the application of the laser beam to the processing chamber is limited, and the application is limited to devices equipped with two or more observation windows for detecting scattered light, and the optical axes of the laser illumination optical system and scattered light detection optical system are adjusted. It was inconvenient to handle because it was necessary to carry out each separately. Furthermore, as a semiconductor manufacturing method and apparatus having a function of in-situ measurement of foreign matters floating in the plasma processing chamber over the entire surface of the wafer, Japanese Patent Laid-Open No. 11-251252 (prior art 8) differs from the plasma excitation frequency. A method and apparatus for detecting floating foreign matter by irradiating the inside of a plasma processing chamber with a laser beam whose intensity is modulated by a frequency from the observation window of the plasma processing chamber and detecting backscattered light from the foreign matter are disclosed. .
[0023]
However, this prior art 8 does not consider the miniaturization of the laser light source to improve the operability.
[0024]
Further, the conventional technique 8 does not take into consideration that it is not affected by the reflected light from the wall surface of the processing chamber, which is one of the problems specific to detecting backscattered light.
[0025]
[Problems to be solved by the invention]
On the other hand, in the field of semiconductors that have been highly integrated into 256 Mbit DRAMs, and further to 1 Gbit DRAMs, the minimum line width of circuit patterns has been continually miniaturized to 0.25 to 0.18 μm, and the size of foreign matter to be detected Submicron orders are also required. However, in the prior art, since it is difficult to separate foreign matter scattered light and plasma emission, application is limited to observation of relatively large foreign matters, and it is considered difficult to detect minute foreign matters on the order of submicrons.
To integrate a laser illumination optical system and scattered light detection optical system and realize a foreign object monitor that can be attached to a single observation window, it propagates backward along the same optical axis as the irradiated laser light, and enters the laser irradiation optical system. A method of detecting backscattered light that returns is effective.
[0026]
Furthermore, in order to realize a smaller monitor, it is important to reduce the size of each component constituting the monitor.
[0027]
In general, a laser light source is larger than other optical elements. In addition, the optical element will be damaged if no physical force is applied from the outside or dust attached to the surface is burned by laser light. probability Is low. In comparison, the lifetime of the laser light source is short. Therefore, as a laser light source for an in-situ monitor, for example, a long-life and small semiconductor laser or a solid-state laser excited by a semiconductor laser is effective. Here, if the particle size of the foreign matter is the same, the intensity of the scattered light generated by the foreign matter is proportional to the output of the laser beam to be irradiated and proportional to the square of the wavelength. Therefore, a solid-state laser excited by a semiconductor laser whose wavelength is shortened by a nonlinear optical crystal is more effective for detecting foreign matter by the laser scattering method than a semiconductor laser.
[0028]
However, since the output and wavelength of the semiconductor laser fluctuate due to changes in the ambient temperature or the temperature of the semiconductor crystal, temperature control is essential. Since the amount of heat generation increases as the output increases, it is necessary to release the generated heat to the outside. Usually, cooling using a Peltier element is performed, and an associated heat sink is used. The size of the heat sink is several to several tens of times that of the semiconductor laser, which is small. From the above, in order to realize a small monitor, it is essential to reduce the size of the laser light source including the heat sink.
[0029]
There is a method in which a laser light source is installed outside and the laser is guided by an optical fiber. However, polarization separation is effective for separating irradiation light and scattered light propagating on the same optical axis. It is possible to guide polarized laser light with a polarization-maintaining fiber. However, when the output is high, the incident end face is damaged and the coupling loss increases even if it is made to enter the narrow polarization plane preserving fiber of the core system. Furthermore, if the laser output is too large, it will be reflected rather than incident on the fiber. The beam diameter can be expanded and guided by a bundle fiber in which several fibers are bundled. However, in order to preserve the polarization plane, it is necessary to align the direction of each fiber, which is quite difficult to realize. is there.
The present invention has been made in view of the above points, and an object of the present invention is a compact and optical axis adjustment that can be attached to a single observation window by integrating a laser illumination optical system and a scattered light detection optical system. Floating foreign object detection with the function to measure in-situ during processing without affecting the semiconductor processing of foreign matter floating in the semiconductor manufacturing equipment by the foreign matter monitor with easy handling and high maintenance efficiency To provide an apparatus.
[0030]
Another object of the present invention is to allow one observation window to be used both as an irradiation optical system and a detection optical system, and to detect foreign matter floating in the processing chamber by an optical system constituted by one unit. There is to do. Another object of the present invention is to realize a method and apparatus for constructing a compact irradiation / detection optical system so that it can be mounted in a limited narrow space. Another object of the present invention is to realize a highly reliable method and apparatus capable of accurately detecting weak foreign matter scattered light. Another object of the present invention is to realize a method and apparatus capable of determining the occurrence of foreign matter on the entire surface of an object to be processed such as a wafer. Another object of the present invention is to provide a semiconductor device processing apparatus having the above-described configuration.
[0031]
[Means for Solving the Problems]
In order to achieve the above-described object, in the present invention, an apparatus for detecting a foreign substance floating inside a semiconductor manufacturing apparatus includes a laser light source unit and a laser excited by a laser emitted from the laser light source unit. A laser irradiation optical system unit for irradiating the laser beam, a scattered light detection optical system unit for detecting a laser beam irradiated by the laser irradiation optical unit and scattered by a foreign object, and a signal processing / control unit, The laser light source unit is connected to the laser irradiation optical system unit with an optical fiber.
In order to achieve the above-described object, in the present invention, an apparatus for detecting foreign matter floating inside a semiconductor manufacturing apparatus using plasma is provided with a laser light source unit and a laser based on the output from the laser light source unit. A monitor optical system comprising: a monitor optical system that detects a laser that is irradiated inside the semiconductor manufacturing apparatus and scattered by foreign matter; and a signal processing / control unit that processes a detection signal of the monitor optical system. The parts are connected to the laser light source part and the signal processing / control part by optical fibers, respectively.
[0032]
In order to achieve the above object, in the present invention, for example, when a desired thin film is generated or processed on a target object in a processing chamber, laser light guided by an optical fiber from an external laser light source, Irradiate into the processing chamber through the observation window. Then, the backscattered light scattered by the foreign matter in the processing chamber is received by the detection optical system through the same observation window, and the number, size and distribution of the foreign matter are discriminated from the detection signal. Display the result on the display.
[0033]
Further, the two-dimensional distribution of the foreign matter is determined by rotating and scanning the irradiation beam irradiated into the processing chamber through the observation window in the horizontal direction.
[0034]
In order to achieve the above-described object, in the present invention, an apparatus for processing a semiconductor device includes a window capable of observing the inside, a placing portion for placing the substrate to be treated inside, and the inside maintained at a predetermined pressure. A plasma processing means for generating a plasma in a processing chamber maintained at a predetermined pressure and processing a substrate to be processed placed on the mounting portion; A laser light source unit disposed outside, a laser irradiation optical system unit that receives a laser emitted from the laser light source unit via an optical fiber, scans the laser from the window, and irradiates the inside of the processing chamber, and the laser The scattered light scattered by the foreign matter floating inside the processing chamber during the processing of the substrate to be processed by the plasma processing means by scanning the laser with the irradiation optical section through the observation window section. Scattered light detection optical system to detect And a signal processing means for outputting information on the foreign matter floating inside the processing chamber by receiving and processing the scattered light signal detected by the scattered light detection optical system section through an optical fiber. .
[0035]
In order to achieve the above-described object, according to the present invention, an apparatus for processing a semiconductor device includes a window capable of observing the inside, a placing portion for placing the substrate to be treated inside, and a predetermined pressure inside the inside. A processing chamber having a pressure setting unit, plasma processing means for generating a plasma in the processing chamber maintained at a predetermined pressure and processing a substrate to be processed placed on the mounting unit, and an outside of the processing chamber A laser light source unit disposed in the laser beam, a laser irradiation optical system unit that receives a laser emitted from the laser light source unit through an optical fiber and scans and irradiates the inside of the processing chamber from the window, and the laser irradiation. The scattered light scattered by the foreign matter floating inside the processing chamber during the processing of the substrate to be processed by the plasma processing means by scanning and irradiating the laser with the optical section through the observation window section. Scattered light detection optical system to detect It was constructed and a signal processing means for outputting information about the foreign substances floating in the processing chamber by receiving and processing signals of the scattered light detected by the scattered light detecting optical system unit via an optical fiber.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
In each embodiment of the present invention described below, an example of application to a parallel plate plasma etching apparatus used in a plasma dry etching apparatus is shown, but the scope of application of the present invention is not limited to this. In addition, the present invention can be applied to thin film generation (film formation) apparatuses such as sputtering apparatuses and CVD apparatuses, or various thin film generation and processing apparatuses such as ECR etching apparatuses, microwave etching apparatuses, and ashing apparatuses. .
First, a first embodiment of the present invention will be described. FIG. 1 shows an etching apparatus and a suspended particle measuring apparatus in plasma according to the first embodiment. The plasma suspended particle measuring apparatus includes a laser irradiation optical system 2010, a scattered light detection optical system 3010, and a signal processing / control system 6010. The laser irradiation optical system 2010 and the scattered light detection optical system 3010 are configured as one unit, and are connected to the laser light source 120 and the signal processing / control system 6010 through optical fibers, respectively.
As shown in FIG. 1, in the etching apparatus, the output voltage of the power amplifier 84 is modulated by the high frequency signal from the signal generator 83, this high frequency voltage is distributed by the distributor 85, and arranged in parallel in the plasma processing chamber 86. This is applied between the upper electrode 81 and the lower electrode 82, and is etched by discharge between both electrodes. N A plasma 71 is generated from the etching gas, and the semiconductor wafer 70 as an object to be processed is etched by the active species. As the high frequency signal generated by the signal generator 83, for example, about 400 kHz is used. In the etching process, the progress of etching is monitored, the end point thereof is detected as accurately as possible, and the etching process is performed for a predetermined pattern shape and depth. When the end point is detected, the output of the power amplifier 84 is stopped and the semiconductor wafer 70 is discharged from the plasma processing chamber 86.
In the laser irradiation optical system 2010, laser light (for example, infrared semiconductor laser light, wavelength: 809 nm) from the excitation laser light source 120 installed at a location distant from the monitor optical system main body is transmitted by the excitation light optical fiber 132. , Gain medium 121 (for example, neodymium vanadate (Nd: YVO) installed in the monitor optical system main body ₄ )). Neodymium vanadate absorbs excitation light having a wavelength of 809 nm and emits strong light in a single direction at a wavelength around 1064 nm. Furthermore, neodymium vanadate is a substance that has different physical properties depending on the axial direction of the crystal, and emits polarized laser light.
The light from neodymium vanadate is then converted by the nonlinear optical crystal 122 (for example, LBO crystal) into laser light having a wavelength of 1064 nm and a second harmonic wavelength of 532 nm.
The wavelength-converted laser light is intensity-modulated at a frequency different from the excitation frequency of the plasma, for example, 170 MHz, by the intensity modulator 123, and then magnified by the collimating lens 116, and the center of the semiconductor wafer 70 by the focusing lens 117. Condensed to
Here, as the intensity modulator 123, for example, there is an AO (Acosto-Optical) modulator. A signal having a frequency different from the excitation frequency of plasma output from an oscillator (not shown) based on a control signal from the computer 161 is applied to the intensity modulator 123, and the wavelength is converted by the nonlinear optical crystal 122. The laser is intensity modulated at this frequency.
Co Lime By appropriately selecting the focal lengths of the coating lens 116 and the focusing lens 117 and making the depth of focus larger than the radius of the semiconductor wafer 70, the front and back regions of the semiconductor wafer 70 are irradiated with a substantially uniform light energy density. It becomes possible to do.
The condensed S-polarized beam is reflected by the polarization beam splitter 124, then converted to a circularly polarized beam by passing through the quarter-wave plate 126, and then reflected by the galvanometer mirror 125 that is driven at a high speed. 10 is incident on the plasma processing chamber 86 and the entire surface of the semiconductor wafer 70 is scanned in a fan shape. By scanning with the long focal depth beam, the entire upper surface of the semiconductor wafer 70 can be irradiated with a substantially uniform energy density.
The circularly polarized beam is scattered by the floating foreign material 72 in the plasma 71. The backscattered light 202 scattered in the backward direction along the same optical axis as the incident beam in the foreign matter scattered light 201 is reflected by the galvanometer mirror 125, and the circularly polarized light component which is a regular reflection component again passes through the quarter wavelength plate 126. By being transmitted, it is converted into P-polarized light, transmitted through the polarization beam splitter 124, and condensed on the incident end surface of the optical fiber 133 by the imaging lens 131.
Here, as shown in FIG. 2, the center 73b of the semiconductor wafer 70 and the fiber light receiving end are in an imaging relationship. Foreign matter scattered light from the front 73a and back 73c of the defocused wafer receiving end. The By setting the size to be capable of receiving light as well, it is possible to receive all foreign matter scattered light generated above the semiconductor wafer 70. Therefore, the semiconductor wafer 70 is combined with the high-speed scanning of the long focal beam. of It is one of the features of the present invention that foreign matter can be detected with almost uniform sensitivity over the entire sky.
[0037]
As in this embodiment, when the wavelength of the illumination light is 532 nm and the particle size of the foreign material is smaller than about 10 μm, most of the polarization component of the backscattered light becomes equal to the polarization component of the incident light. Therefore, in the S-polarized illumination / P-circle light detection (P-polarized illumination / S-polarized light detection) widely known as the polarization separation method, the detection scattering intensity is remarkably lowered and the detection sensitivity is lowered. As described above, it is also one of the features of the present invention that it is possible to suppress a decrease in detection sensitivity due to a decrease in the particle size of foreign matter by using circularly polarized illumination and circularly polarized light detection.
Directly reflected light or scattered light from the inner wall surface of the plasma processing chamber 86 is detected by installing a spatial filter 136 at a point conjugate with the processing chamber wall surface in front of the detection optical fiber to shield the light. The incident on the optical fiber 133 can be prevented. As a result, the backscattered light from the foreign material can be detected without being affected by the reflected light from the processing chamber wall surface, the detection accuracy can be improved, and a smaller floating foreign material or a foreign material with less backscattered light. Can be detected without missing.
One of the features of the present invention is that the directly reflected light from the foreign object observation window 10 is not incident on the optical fiber by tilting the observation window 10 and shifting the reflection optical axis from the detection optical axis.
It is also possible to reduce the reflected light intensity by applying an antireflection coating to the observation window.
The output end of the detection fiber 133 is connected to the interference filter 140, and the same wavelength component (532 nm) as that of the laser beam is extracted and converted into a current signal by the photoelectric conversion element 135 such as a photomultiplier tube. This current signal is amplified by the amplifier 137 in the signal processing / control system 6010 and then sent to the computer 161. The computer 161 sends a scanning control signal 401 to the galvano mirror 125 via the galvano driver 129, and displays the foreign substance scattering intensity at each scanning position on the display 162 while scanning the beam 103.
3 and 4 show display examples on the display 162. FIG. FIG. 3 shows the change of the detection signal for each scanning, that is, the change of time in the wafer central region, with 9 lines of irradiation light on the φ300 mm wafer. When scattered light is generated by floating foreign substances in the plasma, a large signal on the pulse appears as shown at three points in the figure. The size of the foreign matter can be determined from the intensity of these pulse signals. Also, as shown in FIG. 4, at each detection position, if the difference between the output at the nth scan and the output at the (n-1) th scan is taken, the DC component of the background noise is canceled, and Similarly, it is possible to reduce the fluctuation of the background noise that is fluctuating, and the foreign object signal can be easily determined.
When the etching is finished and the wafer 70 is discharged from the processing chamber, the measurement is finished. Measurement data is recorded on a wafer basis. It is also possible to output measurement data to the outside and sequentially monitor the contamination status of the processing chamber plasma processing chamber 87 using the external output signal 402.
[0038]
According to the present embodiment, since the backscattered light is detected, the irradiation and scattered light can be detected through one observation window, and the irradiation optical system and the detection optical system are compactly configured as a monitor optical system with one unit. In addition, since the excitation light source is separated from the monitor optical system body, the cooling heat sink of the excitation light source can be separated from the monitor optical system body, greatly increasing the monitor optical system. It becomes possible to miniaturize.
By miniaturizing the monitor optical system in this way, when it is easily attached to an observation window of an existing semiconductor manufacturing apparatus, the surrounding spatial restrictions for attachment are reduced, and the attachment can be facilitated. it can. In addition, since the miniaturization is possible in this way, the mounting portion of the monitor optical system to the observation window can be easily attached and detached, so that a plurality of semiconductor manufacturing apparatuses can be sequentially monitored by one detection apparatus. It is also possible to do.
By scanning with a long focal beam, it is possible to achieve substantially uniform energy illumination and uniform sensitivity detection over the entire wafer surface. This enables real-time monitoring of the contamination status in the etching apparatus processing chamber, thereby reducing the occurrence of defective wafers due to adhering foreign matter and the effect of accurately grasping the apparatus cleaning time. Moreover, since the frequency of the advance check work using the dummy wafer can be reduced, the effects of cost reduction and productivity improvement are born. Furthermore, since the timing at which foreign matter is generated during processing is known, there is an effect that information effective for foreign matter reduction measures can be obtained.
[0039]
Next, a plasma etching apparatus according to the second embodiment of the present invention will be described. FIG. 5 is a diagram showing a configuration of an etching processing apparatus equipped with a plasma floating particle measuring apparatus according to the second embodiment.
[0040]
As shown in FIG. 5, in the etching processing apparatus 1, the output voltage of the power amplifier 84 is modulated by the high frequency signal from the signal generator 83, and this high frequency voltage is distributed by the distributor 85 to be mutually in the plasma processing chamber 86. Applied between the upper electrode 81 and the lower electrode 82 arranged in parallel, the plasma 71 is generated from the etching gas by the discharge between the two electrodes, and the semiconductor substrate (wafer) W as an object to be processed is produced by the active species. Etch. For example, 400 kHz is used as the high-frequency signal.
[0041]
The in-plasma floating particle measuring apparatus 2 mainly includes a laser illumination / scattered light detection optical system 2000, an excitation light source 3000, and a control / signal processing system 6000. The detection light entrance is disposed to face the observation window 10 provided on the side surface of the plasma processing chamber 86.
[0042]
Here, the intensity of the scattered light that is irradiated with the laser light into the plasma processing chamber 86 and is scattered by the foreign matter in the plasma processing chamber 86 is inversely proportional to the square of the wavelength of the irradiated laser light (the particle size of the foreign matter and the laser beam). When the wavelength is the same), it is proportional to the intensity of the irradiated laser beam. Further, in order to realize a compact plasma floating particle measuring apparatus, it is desired that the laser light source be small. Among laser light sources that are currently commercially available, those having both small and short wavelength conditions include, for example, a solid-state laser (for example, a wavelength of 532 nm, output power) using a semiconductor laser 3000 as excitation light as shown in FIG. ~ 500 mW). However, many of the excitation light source integrated solid-state lasers have a small size of the excitation light source (semiconductor laser) and the constituent optical elements, whereas the size of the heat sink for heat radiation of the excitation light source often increases. This may be disadvantageous for downsizing of the in-plasma floating particle measuring apparatus.
[0043]
Therefore, in the present embodiment, as shown in FIG. 7, the excitation light source 3000 and the wavelength conversion unit 5000 of the excitation light source integrated solid-state laser are separated, and only the wavelength conversion unit 5000 is used as the floating substance measuring apparatus 2 in the plasma. By adopting a configuration to be mounted on, it is intended to reduce the size of the in-plasma suspended particle measuring apparatus.
[0044]
First, laser light from an excitation light source 3000 (for example, a semiconductor laser; wavelength 809 nm) is guided to a laser illumination / scattered light detection optical system 2000 through an optical fiber 4000. Here, since the intensity of the laser light finally irradiated into the plasma processing chamber 86 is proportional to the intensity of the excitation light source 3000, the output from the excitation light source 3000 may be as high as several watts. . As a method for guiding the high-power laser beam, as shown in FIG. 8, a method using a bundle fiber in which a large number of optical fibers are bundled is effective.
[0045]
The laser light guided by the optical fiber 4000 is guided to a wavelength converter 5000 disposed in the laser illumination / scattered light detection optical system 2000. The laser light incident on the wavelength conversion unit 5000 is collected by a focusing lens 5001 and gain medium 5002 (for example, neodymium vanadate (Nd: VO) ₄ ) Crystal or neodymium yag (Nd: YAG) crystal). For example, neodymium vanadate of the gain medium 5002 absorbs the excitation light having the wavelength of 809 nm and emits strong light in a single direction at a wavelength around 1064 nm. Furthermore, neodymium vanadate is a substance that has different physical properties depending on the axial direction of the crystal, and emits polarized laser light. The polarized light having a specific wavelength emitted from the gain medium 5002 is then wavelength-converted by a nonlinear optical crystal 5004 (for example, a second harmonic generation crystal) disposed in the resonator 5003. That is, for example, the LBO crystal of the nonlinear optical crystal 5004 converts laser light having a wavelength of 1064 nm into laser light having a wavelength of 532 nm. The wavelength-converted beam by the nonlinear optical crystal 5004 is wavelength-selected by the resonator 5003 and becomes a laser beam 5008 having a narrow spectral width.
[0046]
Next, the polarized narrow-line-width laser beam 5008 having a specific wavelength is collimated by the collimating lens 5005. The parallel beam is converted into a P-polarized beam 101 by the half-wave plate 27 and then enters an AO (Acousto-Optical) modulator 22. If the polarization direction of the laser beam 5008 is already P-polarized light, the half-wave plate 27 is not necessary. For example, a rectangular wave signal having a frequency of 170 kHz, preferably a duty of 50%, output from the oscillator 23 is applied to the AO modulator 22, and the intensity of the P-polarized beam 101 is modulated at the above frequency. Here, in this embodiment in which the high-frequency voltage applied to the electrode of the etching processing apparatus is 400 kHz, the laser intensity modulation frequency may be 400 kHz and the above-mentioned frequency 170 kHz different from the harmonic components 800 kHz, 1.2 MHz, etc. The reason will be described later.
[0047]
The intensity-modulated P-polarized beam 102 is focused on the center of the wafer W by the focusing lens 18, transmitted through the polarization beam splitter 24 with low loss, and converted into the circularly polarized beam 103 by the quarter-wave plate 26. The light is reflected by the galvanometer mirror 25 and guided to the processing chamber through the observation window 10 provided on the side surface of the plasma processing chamber 86. Here, by rotating the galvanometer mirror 25 and scanning the beam in a plane parallel to the wafer surface, irradiation (foreign matter detection) on the entire surface immediately above the wafer becomes possible.
[0048]
The observation window 10 is reflected by the galvanometer mirror 25, passes through the quarter-wave plate 26 again, becomes S-polarized light, is reflected by the polarization beam splitter 24, and enters the foreign matter scattered light detection optical fiber 3100. It becomes noise. Therefore, in order to prevent noise due to the reflected light from the observation window, the observation window 10 is provided with an inclination, and the reflected light on this surface is not detected because it is offset from the detection optical axis.
[0049]
Next, a method for detecting foreign matter scattered light will be described with reference to FIGS. The circularly polarized beam 103 guided into the plasma processing chamber 86 is scattered by the floating foreign material 72 in the plasma. Backscattered light propagating on the same optical axis as the circularly polarized beam 103 among the foreign matter scattered light passes through the observation window 10, is reflected by the galvanometer mirror 25, and travels toward the polarizing beam splitter 24. Of the backscattered light, the circularly polarized light component corresponding to the direct reflection component passes through the quarter-wave plate 26 again to become S-polarized light, is reflected by the polarization beam splitter 24 with low loss, and is reflected by the imaging lens 31. The light is condensed on the incident surface of the optical fiber 33 for detecting foreign matter scattered light.
[0050]
As shown in FIG. 2, the center 73b of the wafer and the incident surface of the detection optical fiber 33 are in an imaging relationship, but the (light receiving area) of the incident end surface is from the defocused wafer ends 73a and 73c. Scattered light is also detectable. Therefore, foreign matter backscattered light from the front to the back of the wafer can be detected with substantially the same sensitivity. In order to secure a large light receiving surface, a method using a bundle fiber shown in FIG. 8 is effective.
[0051]
Since the scattered light generated on the processing chamber inner wall 5 forms an image in front of the light receiving surface of the foreign matter scattered light detection optical fiber 33 (3100 in FIG. 5), a spatial filter 36 is installed at the image forming position to block the light. The exit end of the foreign-fiber scattered light detection optical fiber 33 is connected to a spectroscope 34 such as a monochromator or an interference filter set to the laser wavelength of the wavelength-converted polarized laser light 5008. After wavelength-separating only the components, the photoelectric conversion element 35 performs photoelectric conversion.
[0052]
The photoelectrically converted detection signal is amplified by an amplifier 50, and then a lock-in amplifier 51 uses a rectangular wave signal having a frequency of 170 kHz and a duty of 50% output from an oscillator 23 used for intensity modulation of laser light as a reference signal. Synchronous detection is performed, and a foreign matter scattered light component having a frequency of 170 kHz is extracted from the detection signal.
[0053]
As shown in FIG. 10, the inventors of the present application have verified through experiments that the intensity of plasma emission is synchronized with the modulation frequency of the high frequency power for plasma excitation. As shown in FIG. 11, the foreign substance signal obtained by wavelength separation by the spectroscope 34 from the plasma emission generated by the high frequency power, and modulation and synchronous detection at the frequency 170 kHz, which is different from the plasma excitation frequency and its integral multiple, From the plasma emission, it is separated and detected in two regions of wavelength and frequency. The inventors of the present application have experimentally confirmed that this method can detect weak foreign matter scattered light from plasma emission with high sensitivity.
[0054]
That is, as shown in FIG. 11, the plasma emission is continuously distributed in the wavelength region, but discretely exists in the frequency region, and there is a free region in the frequency region. Accordingly, for example, a laser beam having a wavelength of 532 nm is incident on the plasma processing chamber after being intensity-modulated at a frequency of 170 kHz, for example, different from the above-mentioned plasma emission frequency. If only the light is taken out, the scattered light from the foreign matter can be detected separately from the plasma emission.
[0055]
The output of the lock-in amplifier 51 is sent to the computer 61. In the computer 61, a scanning signal is sent to the galvano mirror 25 via the galvano driver 29, and the foreign substance signal captured at each scanning position while scanning the beam is displayed on the display one by one in the form as shown in FIG. 3, for example. . In this display example, the signal intensity for each scan with 9 lines of irradiation light on a wafer of φ300 mm is shown. When scattered light is generated by floating foreign matters in the plasma, large signals 80a, 80b and 80c on the pulse appear as shown at three positions in FIG. As shown in FIG. 4, when the difference between the output at the n-th scanning and the output at the (n-1) -th scanning is taken at each detection position, the DC component of the background noise is canceled and the foreign object signal is determined. It becomes easy.
[0056]
In the computer 61, the signal intensity with respect to the particle diameter obtained by experiments in advance and the detected foreign substance signal intensity are compared to determine the size of the foreign substance, the number of foreign substances from the number of the pulse-like signals, and the signal. The occurrence position of the foreign matter is determined from the scanning position when the is detected. Further, the computer 61 determines the contamination status in the processing chamber from the determined number and size of the foreign matter, and terminates the etching process when the total number of foreign matter generation exceeds a preset reference value. Can output information such as informing the operator of the plasma processing apparatus.
[0057]
As described above, according to the present embodiment, by using backscattered light detection, the laser illumination / scattered light detection optical system can be configured by one unit, and the processing apparatus having only one observation window 10 can be used. In addition, the present invention can be applied and the optical axis can be easily adjusted as compared with the case where the illumination optical system and the detection optical system are separated, and the total optical system becomes compact. Further, by separating the excitation light source, which is a heat source and requires a large heat sink, from the irradiation light source, the laser illumination / scattered light detection optical system is separated, so that the total optical system becomes more compact.
[0058]
In addition, the excitation light source, which is estimated to be one of the most frequently exchanged, has a relatively short life compared to other components in the plasma suspended foreign matter measurement device, from the laser illumination / scattered light detection optical system. Because it is separated, only the excitation light source needs to be replaced when replacing the excitation light source, and there is no need to modify the laser illumination / scattered light detection optical system at all. Time can be shortened.
[0059]
In addition, according to the present embodiment, the above-described modulation / synchronous detection method can detect and detect weak scattered light in two regions of wavelength and frequency separately from plasma emission that is a problem in detecting foreign matter in plasma. There is an effect that the detection sensitivity of floating foreign substances in plasma is greatly improved compared to the conventional wavelength separation only method, and the minimum detection sensitivity that can be obtained with only conventional wavelength separation is limited to about φ1μm at most. On the other hand, according to the method of the present invention, the minimum detection sensitivity can be improved to about φ0.2 μm, and the effect of enabling stable foreign object detection over the entire wafer surface is produced. In addition, according to the present embodiment, since the backscattered light detection is performed, the irradiation beam can be rotated and scanned in the horizontal direction, and the two-dimensional distribution of the foreign matter can be easily grasped.
[0060]
Furthermore, according to the present embodiment, foreign matter detection is performed on the entire surface of the wafer to determine the number, size, and distribution of foreign matter, so that the operator can check the information in real time on a display, for example. You can also.
[0061]
Further, according to the present embodiment, the contamination status in the processing chamber can be determined in real time based on the information on the number of generated foreign matters, the size, and the distribution. For example, the cleaning time is optimized, The apparatus operating rate is improved and the occurrence of a defective defect (a large number of defects occurring at a time) can be prevented, thereby improving the yield. In addition, since the processing can proceed while constantly monitoring the contamination status in the processing chamber, the semiconductor substrate and the liquid crystal substrate manufactured in this way are manufactured in an environment that does not contain foreign substances exceeding the reference value, and are of high quality. It becomes a highly reliable product.
[0062]
Further, according to the present embodiment, it is possible to reduce the frequency of determination of contamination status of a processing chamber using a dummy wafer and contamination status determination by sampling inspection, so that the cost of the dummy wafer can be reduced.
[0063]
Next, a plasma etching apparatus according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a diagram showing a configuration of an etching processing apparatus having a suspended particle measuring apparatus in plasma according to the third embodiment.
[0064]
In the configuration shown in FIG. 12, similarly to the configuration shown in FIG. 5, the etching processing apparatus 1 uses the high frequency signal from the signal generator 83 (not shown) to output the output voltage of the power amplifier 84 (not shown). The high frequency voltage is modulated and distributed by a distributor 85 (not shown) and applied between the upper electrode 81 and the lower electrode 82 arranged in parallel with each other in the plasma processing chamber 86, and a discharge between both electrodes is performed. Thus, plasma 71 is generated from the etching gas, and the semiconductor substrate (wafer) W as an object to be processed is etched by the active species. For example, 400 kHz is used as the high-frequency signal.
[0065]
The plasma floating particle measuring apparatus 3 is mainly composed of a laser illumination / scattered light detection optical system 2001, a laser light source 3001, and a control / signal processing system 6000, and an irradiation light exit portion in the laser illumination / scattered light detection optical system 2001. The detection light entrance is disposed to face the observation window 10 provided on the side surface of the plasma processing chamber 86.
[0066]
The difference from the second embodiment described above is that an irradiation laser light source including all of the excitation light source unit and the wavelength conversion unit is arranged outside the laser illumination / scattered light detection optical system 2001. Therefore, even if the irradiation light is increased in output and the size of the laser light source is increased (accordingly, even if the heat sink for heat dissipation is increased), the size of the laser illumination / scattered light detection optical system 2001 is increased. There is nothing.
[0067]
First, a laser beam from a laser light source 3001 (for example, a solid-state laser, a wavelength of 532 nm, an output of up to 500 mW) is incident on the AO modulator 22. For example, a rectangular wave signal having a frequency of 170 kHz, preferably a duty of 50%, output from the oscillator 23 is applied to the AO modulator 22, and the intensity of the P-polarized beam 101 is modulated at the above frequency. Here, as in the second embodiment described above, in this embodiment in which the high frequency voltage applied to the electrode of the etching processing apparatus is 400 kHz, the laser intensity modulation frequency is 400 kHz and its harmonic components 800 kHz, 1.2 MHz. The above-mentioned frequency of 170 kHz, which is different from. The intensity-modulated beam is guided to the laser illumination / scattered light detection optical system 2001 by the bundle fiber 4001. Instead of the bundle fiber 4001, a large diameter fiber 4001a as shown in FIG. 13 may be used. The large-diameter fiber has an advantage that the core diameter is large, and a beam can be incident relatively easily with low loss.
[0068]
Here, the beam emitted from the bundle fiber or the large diameter fiber is a non-polarized beam. The laser light incident on the laser illumination / scattered light detection optical system 2001 is focused on the center of the wafer 70 by the focusing lens 18 and a mirror 240 having a hole with a size that allows the focused beam to pass therethrough. , Is reflected by the galvanometer mirror 25, and guided to the processing chamber through the observation window 10 provided on the side surface of the plasma processing chamber 86. Here, by rotating the galvanometer mirror 25 and scanning the beam in a plane parallel to the wafer surface, irradiation (foreign matter detection) on the entire surface immediately above the wafer becomes possible.
[0069]
The observation window 10 prevents the reflected light from the observation window from being reflected by the galvanometer mirror 25, reflected by the perforated mirror 240, and incident on the foreign matter scattered light detection optical fiber 3100, resulting in large noise. Similar to the second embodiment described above, an inclination is provided.
[0070]
Next, a method for detecting foreign matter scattered light will be described with reference to FIG. The non-polarized irradiation beam guided into the plasma processing chamber 86 is scattered by the floating foreign matter 72 in the plasma. Backscattered light propagating on the same optical axis as the non-polarized irradiation beam in the foreign matter scattered light passes through the observation window 10 and is reflected by the galvanometer mirror 25 and the perforated mirror 240, and the foreign matter scattered light by the imaging lens 31. The light is condensed on the incident surface of the detection optical fiber 33.
[0071]
As in the second embodiment described above, as shown in FIG. 2, the center 73b of the wafer and the incident surface of the foreign matter scattered light detecting optical fiber 33 are in an imaging relationship. ) Has a size capable of detecting scattered light from both defocused wafer ends 73a and 73c. Therefore, foreign matter backscattered light from the front to the back of the wafer can be detected with substantially the same sensitivity. Since the scattered light generated on the processing chamber inner wall 5 forms an image in front of the light receiving surface of the foreign matter scattered light detection optical fiber 33, a spatial filter 36 is installed at the image formation position to block the light. Subsequent apparatus configuration and functions for performing signal processing and foreign matter occurrence status determination are the same as those in the first embodiment, and a description thereof will be omitted.
[0072]
As described above, according to the present embodiment, by using backscattered light detection, the laser illumination / scattered light detection optical system can be configured by one unit, and the processing apparatus having only one observation window 10 can be used. In addition, the present invention can be applied and the optical axis can be easily adjusted as compared with the case where the illumination optical system and the detection optical system are separated, and the total optical system becomes compact. Further, by separating a large laser light source from an excitation light source by a laser illumination / scattered light detection optical system, the total optical system becomes compact.
[0073]
In addition, the laser light source that is estimated to be one of the most frequently exchanged laser light sources from the laser illumination / scattered light detection optical system is relatively short compared to other components in the plasma suspended particle measuring device. Because of the separation, only the laser light source needs to be replaced when replacing the laser light source, and there is no need to modify the laser illumination / scattered light detection optical system at all, thus improving maintenance efficiency and reducing the downtime of the apparatus. It can be shortened.
[0074]
In addition, according to the present embodiment, the above-described modulation / synchronous detection method can detect and detect weak scattered light in two regions of wavelength and frequency separately from plasma emission that is a problem in detecting foreign matter in plasma. There is an effect that the detection sensitivity of floating foreign substances in plasma is greatly improved compared to the conventional wavelength separation only method, and the minimum detection sensitivity that can be obtained with only conventional wavelength separation is limited to about φ1μm at most. On the other hand, according to the method of the present invention, the minimum detection sensitivity can be improved to about φ0.2 μm, and the effect of enabling stable foreign object detection over the entire wafer surface is produced.
[0075]
In addition, according to the present embodiment, since the backscattered light detection is performed, the irradiation beam can be rotated and scanned in the horizontal direction, and the two-dimensional distribution of the foreign matter can be easily grasped.
[0076]
Furthermore, according to the present embodiment, foreign matter detection is performed on the entire surface of the wafer to determine the number, size, and distribution of foreign matter, so that the operator can check the information in real time on a display, for example. Can do.
[0077]
Further, according to the present embodiment, the contamination status in the processing chamber can be determined in real time based on the information on the number of generated foreign matters, the size, and the distribution. For example, the cleaning time is optimized, The apparatus operating rate is improved and the occurrence of a defective defect (a large number of defects occurring at a time) can be prevented, thereby improving the yield. In addition, since the processing can proceed while constantly monitoring the contamination status in the processing chamber, the semiconductor substrate and the liquid crystal substrate manufactured in this way are manufactured in an environment that does not contain foreign substances exceeding the reference value, and are of high quality. It becomes a highly reliable product.
[0078]
Further, according to the present embodiment, it is possible to reduce the frequency of determination of contamination status of a processing chamber using a dummy wafer and contamination status determination by sampling inspection, so that the cost of the dummy wafer can be reduced.
[0079]
Next, a plasma etching apparatus according to a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a diagram illustrating a configuration of an etching processing apparatus having a floating particle measuring apparatus in plasma according to the fourth embodiment.
In the configuration shown in FIG. 15, similarly to the configuration shown in FIG. 5, in the etching processing apparatus 1, the output voltage of the power amplifier 84 (not shown) is generated by a high frequency signal from the signal generator 83 (not shown). The high frequency voltage is modulated and distributed by a distributor 85 (not shown), and between the upper electrode 81 (not shown) and the lower electrode 82 (not shown) arranged in parallel with each other in the plasma processing chamber 86. The plasma 71 is generated from the etching gas by discharge between the electrodes, and the semiconductor substrate (wafer) W as the object to be processed is etched by the active species. For example, 400 kHz is used as the high-frequency signal.
[0080]
The in-plasma floating particle measuring apparatus 4 includes a laser illumination / scattered light detection optical system 2002, a laser light source 3001, a beam splitter 240a, a polarization plane preserving fiber 4002, a polarization plane preserving bundle fiber 4001, and control / signal processing. The irradiation light exit portion and the detection light entrance portion in the laser illumination / scattered light detection optical system 2002 are arranged so as to face the observation window 10 provided on the side surface of the plasma processing chamber 86. ing.
[0081]
The difference from the second embodiment and the third embodiment described above is that the laser beam from the irradiation laser light source 3001 is divided into a plurality of beams, and each of the divided beams is coupled to the polarization plane preserving fiber 4002. The polarization plane preserving fiber 4002 is aligned and bundled so that all the polarization directions are aligned on the exit surface, and the polarized laser light from the bundled polarization plane preserving fiber is converted into the laser illumination / scattered light detection optical system 2002. This is the point that led to Therefore, it is possible to irradiate a high-power polarized laser without increasing the size of the laser illumination / scattered light detection optical system 2002.
[0082]
First, a laser beam from a laser light source 3001 (for example, a solid-state laser, a wavelength of 532 nm, an output of up to 500 mW) is incident on the AO modulator 22. For example, a rectangular wave signal having a frequency of 170 kHz, preferably a duty of 50%, output from the oscillator 23 is applied to the AO modulator 22, and intensity modulation is performed at the above frequency. Here, as in the first and second embodiments, in this embodiment in which the high-frequency voltage applied to the electrode of the etching processing apparatus is 400 kHz, the laser intensity modulation frequency is 400 kHz and its harmonic component 800 kHz, 1 A frequency of 170 kHz or the like different from .2 MHz is preferable.
[0083]
The intensity-modulated laser light is divided into seven by a beam splitter 240a. In the present embodiment, the number of beam divisions is 7. However, the number of beam divisions is not limited to 7, and can be any number of divisions. The divided beams are respectively coupled to the polarization-maintaining fiber 4002 by a coupling lens 5006. Here, the polarization preserving fiber 4002 is generally configured to have a stress applying portion 4002b around the core 4002a as shown in FIG. The core 4002a is smaller than a normal optical fiber (for example, about several μm when the laser wavelength is 532 nm). When a high-power laser beam is incident, the incident surface is damaged, and the beam is not incident. May reflect. Therefore, in this embodiment, the beam is divided, and the intensity of each divided beam is reduced to the extent that it can enter the polarization plane preserving fiber 4002.
[0084]
Next, for example, as shown in FIGS. 17 and 18, the polarization preserving fibers 4002 are aligned and bundled or arranged in an array so that all polarization directions are aligned on the exit surface. Next, the light is guided to the laser illumination / scattered light detection optical system 2002 by the polarization plane preserving bundle fiber 4001. The laser light incident on the laser illumination / scattered light detection optical system 2002 is collimated by the collimating lens 5007 and then condensed at the center of the wafer W by the focusing lens 18. Next, the focused laser beam is converted to P-polarized light by the half-wave plate 27, then transmitted through the polarization beam splitter 24 with low loss, and converted to the circularly polarized beam 103 by the quarter-wave plate 26. The light is reflected by the galvanometer mirror 25 and guided to the processing chamber through the observation window 10 provided on the side surface of the plasma processing chamber 86. Here, by rotating the galvanometer mirror 25 and scanning the beam in a plane parallel to the wafer surface, irradiation (foreign matter detection) on the entire surface immediately above the wafer becomes possible. If the outgoing beam from the polarization plane preserving bundle fiber 4001 is already P-polarized light, the half-wave plate 27 is not necessary.
[0085]
The subsequent apparatus configuration and function for performing signal processing and foreign matter occurrence status determination are the same as those in the second embodiment described above, and thus the description thereof is omitted.
[0086]
As described above, according to the present embodiment, by using backscattered light detection, the laser illumination / scattered light detection optical system can be configured by one unit, and the processing apparatus having only one observation window 10 can be used. In addition, the present invention can be applied and the optical axis can be easily adjusted as compared with the case where the illumination optical system and the detection optical system are separated, and the total optical system becomes compact. Further, by separating a large laser light source from an excitation light source by a laser illumination / scattered light detection optical system, the total optical system becomes compact.
[0087]
In addition, in the plasma suspended particle measuring apparatus, a laser light source 3001 that has a relatively short life and is estimated to be one of the most frequently exchanged parts compared to other components is provided with a laser illumination / scattered light detection optical system. By separating from 2002, when the excitation light source is replaced, only the laser light source 3001 needs to be replaced, and there is no need to make any changes to the laser illumination / scattered light detection optical system 2002, thereby improving maintenance efficiency. The downtime of the apparatus can be shortened.
[0088]
Further, according to the present embodiment, a high-power polarized laser beam can be guided from the outside of the laser illumination / scattered light detection optical system 2002.
[0089]
In addition, according to the present embodiment, the above-described modulation / synchronous detection method can detect and detect weak scattered light in two regions of wavelength and frequency separately from plasma emission that is a problem in detecting foreign matter in plasma. There is an effect that the detection sensitivity of floating foreign substances in plasma is greatly improved compared to the conventional wavelength separation only method, and the minimum detection sensitivity that can be obtained with only conventional wavelength separation is limited to about φ1μm at most. On the other hand, according to the method of the present invention, the minimum detection sensitivity can be improved to about φ0.2 μm, and the effect of enabling stable foreign object detection over the entire wafer surface is produced.
[0090]
In addition, according to the present embodiment, since the backscattered light detection is performed, the irradiation beam can be rotated and scanned in the horizontal direction, and the two-dimensional distribution of the foreign matter can be easily grasped.
[0091]
Furthermore, according to the present embodiment, foreign matter detection is performed on the entire surface of the wafer to determine the number, size, and distribution of foreign matters, so that the operator can check the information on a display in real time, for example.
[0092]
Further, according to the present embodiment, the contamination status in the processing chamber can be determined in real time based on the information on the number of generated foreign matters, the size, and the distribution. For example, the cleaning time is optimized, The apparatus operating rate is improved and the occurrence of a defective defect (a large number of defects occurring at a time) can be prevented, thereby improving the yield. In addition, since the processing can proceed while constantly monitoring the contamination status in the processing chamber, the semiconductor substrate and the liquid crystal substrate manufactured in this way are manufactured in an environment that does not contain foreign substances exceeding the reference value, and are of high quality. It becomes a highly reliable product.
[0093]
Further, according to the present embodiment, it is possible to reduce the frequency of determination of contamination status of a processing chamber using a dummy wafer and contamination status determination by sampling inspection, so that the cost of the dummy wafer can be reduced.
[0094]
Next, a light source system for supplying a laser beam to the laser illumination / foreign particle scattered light detection optical system of a suspended particle measurement apparatus in plasma according to a fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, a laser beam divided into a plurality of beams is coupled to a plurality of bundle fibers or large-diameter fibers, and the output from each bundle fiber or large-diameter fiber is respectively reflected in the laser illumination and the above-described fourth embodiment. The light is guided to the scattered light detection optical system 2002. Therefore, the configuration and performance of the etching processing apparatus having the plasma suspended foreign substance measuring apparatus are the same as those in the fourth embodiment described above, and therefore illustration and description thereof are omitted here.
[0095]
In the configuration shown in FIG. 19, a laser beam emitted from a laser light source 3001 (for example, a solid-state laser, a wavelength of 532 nm, an output of −500 mW) is incident on the AO modulator 22. For example, a rectangular wave signal having a frequency of 170 kHz, preferably a duty of 50%, output from the oscillator 23 is applied to the AO modulator 22, and intensity modulation is performed at the above frequency. Here, in this embodiment in which the high-frequency voltage applied to the electrode of the etching processing apparatus is 400 kHz, the laser intensity modulation frequency may be 400 kHz and the above-mentioned frequency 170 kHz different from the harmonic components 800 kHz, 1.2 MHz, etc. The reason is as described in the second embodiment.
[0096]
The intensity-modulated beam is divided into four by a beam splitter 240. In this embodiment, the number of beam divisions is four. However, the number of beam divisions is not limited to four, and can be any number of divisions. The divided beams are coupled to bundle fibers 4000a to 4000d by coupling lenses 5006, respectively. Then, the bundle fibers 4000a to 4000d are respectively guided to the laser illumination / scattered light detection optical system 2001 shown in the second embodiment.
Since the subsequent apparatus configuration and functions for performing signal processing and foreign matter occurrence status determination are the same as those in the fourth embodiment, illustration and description are omitted.
[0097]
As described above, according to the present embodiment, the same effects as those of the fourth embodiment described above can be obtained, and an etching processing apparatus having a plurality of suspended particle measuring apparatuses in plasma can be configured with one laser light source. Therefore, it is effective for cost reduction.
[0098]
Next, a laser light source system according to a sixth embodiment of the present invention will be described with reference to FIG. In this embodiment, a plurality of divided laser beams are coupled to each polarization plane preserving bundle fiber, each polarization plane preserving fiber is divided into several sets, and bundled so that the polarization directions are aligned on the exit surface, and each polarization plane preserving is performed. The bundle fibers are respectively guided to the laser illumination / scattered light detection optical system 2002 shown in the fourth embodiment. Therefore, the configuration and performance of the etching processing apparatus having the plasma suspended foreign substance measuring apparatus are the same as those in the fourth embodiment described above, and therefore illustration and description thereof are omitted here.
[0099]
In the configuration shown in FIG. 20, a laser beam from a laser light source 3001 (for example, a solid-state laser, a wavelength of 532 nm, an output of −500 mW) is incident on the AO modulator 22. For example, a rectangular wave signal having a frequency of 170 kHz, preferably a duty of 50%, output from the oscillator 23 is applied to the AO modulator 22, and intensity modulation is performed at the above frequency. Here, in this embodiment in which the high-frequency voltage applied to the electrode of the etching processing apparatus is 400 kHz, the laser intensity modulation frequency may be 400 kHz and the above-mentioned frequency 170 kHz different from the harmonic components 800 kHz, 1.2 MHz, etc. The reason is as described in the second embodiment.
[0100]
The intensity-modulated beam is divided into eight by a beam splitter 240a. In this embodiment, the number of beam divisions is 8. However, the number of beam divisions is not limited to 8, and can be any number of divisions. The divided beams are coupled to the polarization-maintaining fiber 4002 by a coupling lens 5006, respectively. The polarization-maintaining fibers 4002 are bundled two by two to form four sets of polarization-maintaining fiber bundles 4003a to 4003d. In the present embodiment, the eight polarization plane preserving fibers 4002 are made into four bundle fibers 4003a to 4003d. However, the number of bundles is not limited to this, and the floating particles in the plasma are not bundled. It may be guided to a measuring device, or may be divided into two sets of polarization plane preserving bundle fibers, and a desired combination can be set as appropriate.
[0101]
Next, the polarization plane preserving bundle fibers 4002a to 4002d are guided to the laser illumination / scattered light detection optical system 2002 shown in the fourth embodiment. Since the subsequent apparatus configuration and functions for performing signal processing and foreign matter occurrence status determination are the same as those in the fourth embodiment, illustration and description are omitted.
[0102]
As described above, according to the present embodiment, the same effects as those of the fourth embodiment described above can be obtained, and an etching processing apparatus having a plurality of suspended particle measuring apparatuses in plasma can be configured with one laser light source. Therefore, it is effective for cost reduction.
[0103]
Next, a laser light source system according to a seventh embodiment of the present invention will be described with reference to FIG. In the present embodiment, the divided laser beams are intensity-modulated by AO modulators, respectively, and then coupled to bundle fibers or large-diameter fibers, respectively, and the outputs from the bundle fibers or large-diameter fibers are respectively described above. This is guided to the laser illumination / scattered light detection optical system 2002 shown in the fourth embodiment. Therefore, the configuration and performance of the etching processing apparatus having the plasma suspended foreign substance measuring apparatus are the same as those in the fourth embodiment described above, and thus the description thereof is omitted here.
[0104]
In the configuration shown in FIG. 21, a laser beam from a laser light source 3001 (for example, a solid-state laser, a wavelength of 532 nm, an output of ~ 500 mW) is divided into four by a beam splitter 240. In this embodiment, the number of beam divisions is four. However, the number of beam divisions is not limited to four, and can be any number of divisions. The split beam is incident on the multi-channel AO modulator 220. A rectangular wave signal output at a frequency set by the calculators 61a to 61d from the multi-channel oscillator 230 is applied to the AO modulator 220, preferably with a duty of 50%, and intensity modulation is performed at the above frequency. Here, the frequency is appropriately set in consideration of the frequency of the high-frequency voltage applied to the electrode of the etching processing apparatus.
[0105]
The split beams from the intensity-modulated beams are coupled to bundle fibers 4000a to 4000d by coupling lenses 5006, respectively. Then, the bundle fibers 4000a to 4000d are respectively guided to the laser illumination / scattered light detection optical system 2002 shown in the third embodiment. Since the subsequent apparatus configuration and functions for performing signal processing and foreign matter occurrence status determination are the same as those in the fourth embodiment, illustration and description are omitted.
[0106]
As described above, according to the present embodiment, the same effects as those of the third and sixth embodiments described above can be obtained, and a single laser light source can be used in various plasmas having a plurality of different plasma excitation frequencies. An etching processing apparatus with a floating particle measuring apparatus can be configured.
[0107]
Next, an eighth embodiment of the present invention will be described based on FIG. 22, FIG. 23 and FIG. First, the concept of the method for manufacturing a semiconductor integrated circuit device according to the present invention will be described with reference to FIGS.
[0108]
Step 1001 is a film forming step for forming a film to be processed 601 such as a silicon oxide film on the wafer W, and step 1002 is a film thickness measuring step for inspecting the thickness of the formed film. Step 1003 is a resist coating step for applying a resist 602 to the wafer W, and step 1004 is a pattern transfer step for transferring the mask pattern 603 onto the wafer. Step 1005 is a developing step for removing the resist in the processed portion. Step 1006 uses the resist pattern 604 as a mask to etch the processed film 601 in the resist removing portion 605 to form wiring grooves and contact holes 606. Etching process. Step 1007 is an ashing step for removing the resist pattern 604, and step 1008 is a cleaning step for cleaning the front surface and the back surface of the wafer. The above series of steps is applied to, for example, formation of a contact hole.
[0109]
In a normal semiconductor integrated circuit device, a multilayer structure is formed by repeating the above series of steps.
[0110]
Next, with reference to FIG. 24, a description will be given of defects caused by foreign matters generated during etching adhering to the wafer. FIG. 24 is a diagram illustrating an example of defects generated in, for example, contact hole etching.
[0111]
A foreign substance 701 indicates a foreign substance attached to the contact hole opening during etching. In this case, since the etching reaction is stopped by the adhered foreign matter, the contact hole at the foreign matter adhered portion is not opened, which becomes a fatal defect.
[0112]
A foreign substance 702 indicates a foreign substance adhering to the inside of the contact hole during etching. Also in this case, since the etching reaction is stopped by the adhered foreign matter, the contact hole at the foreign matter adhered portion is not opened, resulting in a fatal defect.
[0113]
A foreign matter 703 and a foreign matter 704 indicate foreign matters that have adhered to the inside of the contact hole after etching. A foreign substance adhering to a portion having a high aspect ratio such as a contact hole is often difficult to remove even by cleaning. If the size of the foreign substance is large, such as a foreign substance 703, a contact failure occurs, which is fatal. It becomes a defect.
[0114]
A foreign matter 705 indicates foreign matter attached to the resist pattern 604 during etching. In this case, the attached foreign matter 705 does not affect the etching reaction at all, and no fatal defect occurs due to the attached foreign matter 705.
[0115]
In this way, even if foreign matter adheres, if the size of the foreign matter is not large enough to cause a defect, or if the attachment location is a non-etched area, it does not become a fatal defect and the foreign matter adheres to the wafer. But not all of them cause fatal defects. In addition, the foreign matter 701 and the foreign matter 705 are foreign matters that are relatively easy to remove by cleaning, whereas the foreign matter that has fallen into the high aspect ratio contact hole, such as the foreign matter 602, the foreign matter 703, and the foreign matter 704, is removed by washing. Is difficult.
[0116]
In the present invention, in the etching process 1006, the foreign substance generated in the processing chamber during the etching is detected in real time by the plasma floating foreign substance measuring apparatus 1100, and the processed wafer is transferred to the next process based on the foreign substance detection result. It is selected whether the remaining wafers are processed sequentially, whether the appearance inspection is performed before being sent to the next process, or the processing is stopped and the processing chamber is cleaned (maintenance).
[0117]
Here, the process to be performed next is selected by comparing the size and number of detected foreign substances with a preset standard value (foreign substance management standard).
[0118]
Therefore, an example of a method for calculating the standard value (foreign matter management standard) in the present embodiment will be described next. As already explained, even if foreign matter adheres to the wafer, not all of them cause fatal defects. The probability that a fatal defect occurs due to the adhered foreign matter can be obtained by calculation from the relationship between the opening ratio and pattern density of the etching pattern, the wiring width, and the size and number of foreign matter that adhere. Therefore, the correlation between the size and number of foreign matter detected during the etching process and the size and number of foreign matter attached to the wafer is obtained in advance through experiments, and the probability that fatal defects are caused by the foreign matter detected during etching. Can be requested.
[0119]
The standard value (foreign matter management standard) is set based on the value obtained by the above means. In the following, an example of setting a standard value in the present embodiment is shown.
[0120]
The standard value 1 is set so that the probability of occurrence of a fatal defect is very low (for example, the probability of occurrence of a fatal defect is 1% or less) if the number of detected foreign objects of a certain size or less is smaller than the specified value 1. . For example, the standard value 1 is 10 particles having a particle size of 0.4 μm or more.
[0121]
The standard value 2 is a value at which the occurrence of a fatal defect is a concern (for example, the probability of the fatal defect occurrence) if the number of detected foreign objects of a certain size or more is less than the specified value 2 above the standard value 1 5% or less). For example, the standard value 2 is 30 particles having a particle size of 0.4 μm or more.
[0122]
When the number of detected foreign objects having a certain size or more is the specified value 2 or more, many fatal defects occur (for example, a fatal defect occurrence probability of 5% or more).
[0123]
Based on the standard value, if the number of foreign particles detected during the etching process is less than the specified value 1, the probability of a fatal defect is low, so that the next wafer is processed. Do.
[0124]
If the number of foreign substances detected during the etching process is greater than or equal to the specified value 1 but less than the specified value 2, an appearance inspection is performed after the etching process is completed. If no fatal defect is confirmed as a result of the visual inspection, the wafer is sent to the next ashing step 1007. If a fatal defect is confirmed as a result of the visual inspection, it is determined whether the fatal defect is a remedyable defect. If it is determined that the defect can be repaired (eg, use of a repair circuit) based on the determination result, the wafer is sent to the next ashing step 1007. If it is determined that the defect cannot be repaired based on the determination result, the defect is recorded and then the wafer is sent to the next ashing step 1007. Thereafter, for example, when each chip is cut out by dicing, the chip including the irreparable defect is eliminated.
[0125]
In the case where the number of foreign substances detected during the etching process is larger than the specified value 2, the possibility of a large number of fatal defects occurring in the wafer to be processed thereafter is high. An operator of the etching apparatus is displayed on a monitor screen or notified by an alarm so that the etching process is interrupted and the plasma processing chamber is cleaned (maintenance). In an etching processing apparatus that does not include a plasma floating particle measuring apparatus, the processing chamber is not necessarily cleaned in an appropriate time. Therefore, cleaning is performed at a time when it is not necessary to clean, and the operation rate of the apparatus is reduced, or conversely, processing is continued even when the time to be cleaned has passed, resulting in a large amount of defective products and yield. It may be reduced.
[0126]
There is also a method of performing a prior work with a dummy wafer for checking foreign matter in the processing chamber and determining the cleaning time from the result. In this case, extra work is performed during a series of steps, resulting in a decrease in throughput and a cost for dummy wafers. However, with the increase in wafer diameter, the cost of dummy wafers is inevitably increased, and the reduction of prior work using dummy wafers for checking foreign substances in the processing chamber is also a big problem.
[0127]
On the other hand, according to the present embodiment, since the object to be processed can be processed while monitoring the contamination status in the processing chamber in real time, the cleaning time is optimized, and no prior work with a dummy wafer is required, so that the throughput is increased. The cost of the dummy wafer can be reduced. In addition, the product manufactured by the process of the present embodiment can manufacture a high-quality product that does not include foreign substances exceeding a specified value, and thus a highly reliable product.
In the above embodiment, the application example to the etching processing apparatus has been described. However, as described above, the scope of application of the present invention is not limited to this. By applying to an apparatus or a film forming apparatus, real-time monitoring of foreign matter in the ashing apparatus and the film forming apparatus becomes possible, thereby reducing defects caused by the ashing process and the film forming process during the photolithography process. Therefore, it is possible to prevent the occurrence of defective products and improve the yield.
[0128]
【The invention's effect】
As described above, according to the present invention, by using backscattered light detection, the laser illumination / scattered light detection optical system can be constituted by one unit, and the processing apparatus having only one observation window. In addition, the present invention can be applied and the optical axis can be easily adjusted as compared with the case where the illumination optical system and the detection optical system are separated, and the total optical system becomes compact.
[0129]
Further, by separating the excitation light source, which is a heat source and requires a large heat sink, from the irradiation light source, the laser illumination / scattered light detection optical system is separated, so that the total optical system becomes more compact.
[0130]
Further, according to the present invention, an excitation light source that is estimated to be one of the most frequently exchanged laser light sources with a relatively short life compared to other components in the plasma suspended foreign matter measuring apparatus is provided. By separating from the scattered light detection optical system, it is only necessary to replace the excitation light source when replacing the excitation light source, and there is no need to modify the laser illumination / scattered light detection optical system at all. And the downtime of the apparatus can be shortened.
[0131]
In addition, according to the present invention, it is possible to separate and detect weak foreign matter scattered light in two regions of wavelength and frequency from plasma light emission which is a problem in foreign matter detection in plasma. Compared to the above, the effect of greatly improving the detection sensitivity of the floating foreign matters in the plasma is obtained, and the minimum detection sensitivity obtained in the case of only the conventional wavelength separation is limited to about φ1 μm at most, whereas According to the method, the minimum detection sensitivity can be improved to about φ0.2 μm, and an effect that stable foreign matter detection can be performed over the entire wafer surface is produced.
[0132]
Further, according to the present invention, since the backscattered light detection is performed, the irradiation beam can be rotationally scanned in the horizontal direction, and the two-dimensional distribution of the foreign matter can be easily grasped.
[0133]
Further, according to the present invention, foreign matter detection is performed on the entire surface of the wafer to determine the number, size, and distribution of the foreign matter, so that the operator can check the information in real time on a display, for example. it can.
[0134]
Further, according to the present invention, the contamination status in the processing chamber can be determined in real time based on the information on the number of generated foreign matters, the size, and the distribution. For example, the cleaning time is optimized, The apparatus operating rate is improved and the occurrence of a defective defect (a large number of defects occurring at a time) can be prevented, thereby improving the yield. In addition, since the processing can proceed while constantly monitoring the contamination status in the processing chamber, the semiconductor substrate and the liquid crystal substrate manufactured in this way are manufactured in an environment that does not contain foreign substances exceeding the reference value, and are of high quality. It becomes a highly reliable product.
[0135]
Further, according to the present embodiment, it is possible to reduce the frequency of determination of contamination status of a processing chamber using a dummy wafer and contamination status determination by sampling inspection, so that the cost of the dummy wafer can be reduced.
[0136]
These effects enable real-time monitoring of the contamination status in the etching chamber, reduce the occurrence of defective wafers due to attached foreign matter, enable the production of high-quality semiconductor elements, and accurately time to clean the equipment. The effect of being able to grasp is born.
[0137]
In addition, since the frequency of the foreign object prior work check operation using the dummy wafer can be reduced, the effects of cost reduction and productivity improvement are produced. In addition, the production line can be automated.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an etching processing apparatus having a floating particle measuring apparatus in plasma according to a first embodiment of the present invention. It is the top view and front view which show schematic structure of the etching apparatus with which the floating foreign material measuring apparatus in plasma in the 1st Example of this invention was mounted | worn.
FIG. 2 is a schematic front view showing a schematic relationship between an imaging position on a wafer of an optical system and an inner wall surface of a processing apparatus.
FIG. 3 is an explanatory diagram showing a state where the plasma excitation frequency and the plasma emission are synchronized in each embodiment of the present invention.
FIG. 4 is an explanatory diagram showing a state of wavelength / frequency separation from plasma emission of foreign matter scattered light in each embodiment of the present invention.
FIG. 5 is a diagram showing a configuration of an etching processing apparatus equipped with a plasma floating particle measuring apparatus according to a second embodiment of the present invention.
FIG. 6 is an explanatory diagram showing a general configuration of a semiconductor laser-excited solid-state laser in a second embodiment of the present invention.
FIG. 7 is a schematic front view showing a schematic configuration of an external laser excitation solid-state laser in which an excitation light source and a wavelength conversion unit are separated according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a cross-sectional structure of a bundle fiber.
FIG. 9 is a diagram for explaining a schematic configuration of an etching apparatus equipped with an optical system for detecting foreign matter scattered light in a second embodiment of the present invention.
FIG. 10 is a diagram showing temporal changes in detected light intensity at nine points on a wafer in the second embodiment of the present invention.
FIG. 11 is a three-dimensional graph showing the temporal change of the foreign substance signal intensity at nine points on the wafer in the second embodiment of the present invention.
FIG. 12 is a schematic plan view showing a schematic configuration of an etching processing apparatus equipped with a floating particle measuring apparatus in plasma according to a third embodiment of the present invention.
FIG. 13 is a cross-sectional view of a large diameter fiber according to a third embodiment of the present invention.
FIG. 14 is a plan view of an etching apparatus equipped with an optical system for detecting foreign matter scattered light in a third embodiment of the present invention.
FIG. 15 is a plan view showing a schematic configuration of an etching processing apparatus equipped with a floating particle measuring apparatus in plasma according to a fourth embodiment of the present invention.
FIG. 16 is a cross-sectional view of a polarization-maintaining fiber according to a fourth embodiment of the present invention.
FIG. 17 is a cross-sectional view of a polarization-maintaining bundle fiber according to a fourth embodiment of the present invention.
FIG. 18 is a cross-sectional view of a polarization-maintaining array fiber according to the fourth embodiment of the present invention.
FIG. 19 is a schematic plan view showing an external laser light source according to a fifth embodiment of the present invention.
FIG. 20 is a schematic plan view showing an external laser light source according to a sixth embodiment of the present invention.
FIG. 21 is a schematic plan view showing an external laser light source according to a seventh embodiment of the present invention.
FIG. 22 is a process flow diagram showing a process flow of a manufacturing process of a semiconductor integrated circuit device in which an etching processing apparatus with a suspended particle measurement apparatus in plasma according to an eighth embodiment of the present invention is introduced. is there.
FIG. 23 is a diagram for explaining a processing flow schematically showing a contact hole formation process according to an eighth embodiment of the present invention along a processing flow using a cross-sectional structure; is there.
FIG. 24 is a cross-sectional view of a substrate to be processed schematically showing an example of defects caused by attached foreign substances in a contact hole etching step according to an eighth embodiment of the present invention.
FIG. 25 is an explanatory view showing a conventional parallel plate type plasma etching apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Etching processing apparatus 10 ... Observation window 22, 122 ... AO modulator 23, 123 ... Oscillator 24, 124 ... Polarizing beam splitter 25, 125 ... Galvano mirror 35 ... -Photoelectric conversion element 50-Amplifier 51-Lock-in amplifier 61-Computer 2000-Laser illumination / scattered light detection optical system 3000-Excitation light source 33, 3100-For detecting foreign matter scattered light Optical fiber 4000 ... Optical fiber 5000 ... Wavelength conversion unit 6000 ... Control / signal processing system

Claims (19)

An apparatus for detecting foreign matter floating inside a plasma processing apparatus for processing a semiconductor device,
A laser light source unit integrated with an excitation light source that outputs a laser and includes a heat sink for heat radiation;
A laser irradiation optical system that scans and irradiates a laser inside an apparatus that receives the laser emitted from the laser light source and processes the semiconductor device;
A scattered light detection optical system unit that detects a laser beam that is scanned by the laser irradiation optical system unit and scattered by a foreign substance floating inside the apparatus that processes the semiconductor device;
A signal processing unit that processes the detection signal of the scattered light detection optical system unit and outputs information about the foreign matter floating inside the apparatus for processing the semiconductor device;
With
The laser irradiation optical system unit and the scattered light detection optical system unit are composed of one unit,
Before chelating chromatography The light source unit includes an excitation light source and the wavelength converting portion, and the excitation light source and the wavelength converting portion are connected by a separate optical fiber, the wavelength conversion portion composed of the one unit An apparatus for detecting floating foreign matter in a plasma processing apparatus, wherein the scattered light detection optical system section and the laser irradiation optical system section are arranged in the same unit . 2. The floating foreign matter detection apparatus in a plasma processing apparatus according to claim 1, wherein the scattered light detection optical system section includes a light blocking section that blocks reflected light from the inner wall surface of the semiconductor manufacturing apparatus.   2. The apparatus for detecting floating foreign matter in a plasma processing apparatus according to claim 1, wherein the laser for scanning and irradiating the inside of the apparatus for processing the semiconductor device is modulated in intensity at a desired frequency.   2. The floating foreign substance detection apparatus in a plasma processing apparatus according to claim 1, wherein the signal processing unit outputs information on the number, size, and distribution of foreign substances floating inside the apparatus for processing the semiconductor device. . An apparatus for detecting foreign matter floating inside a plasma processing apparatus for processing a semiconductor device using plasma,
A laser light source unit integrated with an excitation light source that outputs a laser and includes a heat sink for heat radiation;
Scatter scattered from foreign matter floating in the plasma processing apparatus by receiving the laser output from the laser light source unit and irradiating the plasma processing apparatus with the laser through the observation window of the plasma processing apparatus A monitor optical system for detecting light through the observation window;
A signal processing unit for processing a detection signal obtained by detecting the scattered light by the monitor optical system unit;
With
Before chelating chromatography The light source unit includes an excitation light source and the wavelength converting portion, and the excitation light source and the wavelength converting portion are separated, the wavelength conversion portion is disposed inside of the monitor optical system unit, The floating foreign matter detection apparatus in the plasma processing apparatus, wherein the excitation light source, the wavelength conversion unit, the monitor optical system unit, and the signal processing unit are connected by optical fibers, respectively.   The laser light source unit outputs an excitation laser, and the monitor optical system unit irradiates the inside of the plasma processing apparatus with a laser excited by the excitation laser output from the laser light source unit. Item 6. A floating foreign matter detection apparatus in a plasma processing apparatus according to Item 5.   6. The floating foreign matter detection apparatus in a plasma processing apparatus according to claim 5, wherein the monitor optical system unit is configured to be detachable from an observation window of the plasma processing apparatus.   6. The floating foreign substance detection apparatus in a plasma processing apparatus according to claim 5, wherein the signal processing unit outputs information on the number, size, and distribution of foreign substances floating inside the plasma processing apparatus.   6. The floating foreign matter in the plasma processing apparatus according to claim 5, wherein the monitor optical system section irradiates the circularly polarized light inside the apparatus for processing the semiconductor device and detects the circularly polarized light scattered by the foreign matter. Detection device.   The monitor optical system unit shields light reflected from an inner wall surface of the apparatus for processing the semiconductor device by a laser irradiated inside the plasma processing apparatus, and scattered light from foreign matters floating inside the plasma processing apparatus. The apparatus for detecting floating foreign matter in a plasma processing apparatus according to claim 5, wherein:   6. The floating foreign matter detection apparatus in a plasma processing apparatus according to claim 5, wherein the intensity of the laser that scans and irradiates the inside of the plasma processing apparatus is modulated at a desired frequency. A method for detecting foreign matter floating inside a plasma processing apparatus,
A laser from the pumping light source in the pumping light source integrated laser source unit including a pumping light source including a heat sink for heat dissipation and a wavelength conversion unit that is separated from the pumping light source and connected to the pumping light source by an optical fiber. Fire,
Is incident the firing laser to the laser irradiation optical system unit which is installed through the wavelength converting portion therein through said optical fiber,
A laser is scanned into the inside of the plasma processing apparatus through the observation window of the plasma processing apparatus for processing the semiconductor device with plasma from the laser irradiation optical system unit on which the laser is incident.
Detecting scattered light scattered by foreign matter floating inside the plasma processing apparatus through the observation window by scanning and irradiating the laser inside the plasma processing apparatus,
Transmitting the detected scattered light signal to the signal processing unit via the second optical fiber;
Floating in the plasma processing apparatus characterized in that information on foreign matters floating in the plasma processing apparatus is obtained by processing the scattered light signal received by the signal processing unit via the second optical fiber. Foreign object detection method.   13. The method for detecting floating foreign matter in a plasma processing apparatus according to claim 12, wherein reflected light from the inner wall surface of the plasma processing apparatus is shielded to detect scattered light scattered by the foreign substance.   13. The method for detecting floating foreign matter in a plasma processing apparatus according to claim 12, wherein the intensity of the laser that scans and irradiates the inside of the plasma processing apparatus is modulated at a desired frequency.   13. The floating in the plasma processing apparatus according to claim 12, wherein information on the number, size, and distribution of foreign substances floating in the plasma processing apparatus is obtained by processing the detected scattered light signal. Foreign object detection method. A processing chamber comprising a window part capable of observing the inside, a placing part for placing the substrate to be treated in the inside, and a pressure setting part for maintaining the inside at a predetermined pressure;
Plasma processing means for generating a plasma inside the processing chamber maintained at a predetermined pressure and processing a substrate to be processed placed on the placing portion;
An excitation light source and the excitation light source with a heat sink for the heat release and the laser light source portion of the excitation light source integral with a wavelength converting portion connected with the separated excitation light source and the first optical fiber,
By arranging the wavelength converting portion therein, it receives the laser emitted from the laser light source unit and the excitation light source is output from the incident on the wavelength converting portion through the first optical fiber wavelength conversion of Then, the inside of the processing chamber that is processing the substrate to be processed by the plasma processing means is irradiated with a laser through an observable window portion of the processing chamber, and scattered by the foreign matter floating in the processing chamber by the irradiation. A monitor optical system that detects the scattered light that has been observed through the observable window;
A signal processing unit that obtains information about the foreign matter floating in the processing chamber by receiving and processing the detection signal of the monitor optical system unit via a second optical fiber at a location away from the processing chamber;
An apparatus for processing a semiconductor device, comprising: 17. The semiconductor device processing apparatus according to claim 16, wherein the monitor optical system section is detachably attached to the observable window section of the processing chamber. The monitor optical system unit is configured to shield light reflected from an inner wall surface of the processing chamber by a laser irradiated to the inside of the processing chamber and detect scattered light caused by foreign matters floating inside the processing chamber. 17. The semiconductor device processing apparatus according to claim 16 . 17. The semiconductor device processing apparatus according to claim 16 , wherein the signal processing unit outputs information on the number, size, and distribution of foreign matters floating in the processing chamber.

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