JP6222656B2 - Sensor-integrated suction chuck and processing device - Google Patents

Description

  The present invention relates to a sensor-integrated adsorption chuck and a processing apparatus, and in an adsorption chuck such as an electrostatic chuck that adsorbs a substrate, abnormal discharge or displacement generated around a sample adsorbed on the surface of the adsorption chuck. The present invention relates to a sensor-integrated suction chuck and a processing apparatus having a mechanism for detecting the sensitivity with high sensitivity.

  Currently, in the field of semiconductor manufacturing, a plasma processing method for processing a substrate to be processed using plasma discharge is widely used for the purpose of plasma CVD, ashing, etching, sputtering, surface treatment, and the like.

  In such a plasma processing process, abnormal discharge of plasma generated in the plasma processing apparatus causes problems such as generation of dust, damage to the surface of the substrate to be processed, contamination of the substrate, dielectric breakdown of electronic elements provided on the substrate. is there. Therefore, in order to cope with such a problem, accurate detection of occurrence of abnormal discharge is required.

  Various studies have been made to meet such demands, and in abnormal discharge, changes in plasma emission intensity, changes in power supply voltage / current, changes in plasma impedance, or changes in harmonics are detected. It has been tried.

  Further, in the reproducibility and stability of plasma, that is, confirmation of fluctuations, detection of fluctuations in plasma is attempted by detecting fluctuations in gas pressure and changes in emission spectrum. Further, in order to monitor a change in voltage or current of the RF power supply or a change in plasma impedance, a detector is inserted into the power supply line.

  Also, ultrasonic waves (AE: Acoustic Emission) are generated when abnormal discharge occurs, and the ultrasonic waves generated when abnormal discharge occurs are processed using the propagation of the generated AE wave through the structure (elastic body). An attempt has been made to detect with an AE sensor attached to an appropriate number of locations on the outer wall surface, upper surface portion or lower surface portion of the chamber.

  FIG. 7 is a schematic configuration diagram of a conventional plasma processing apparatus with an abnormal discharge detection mechanism. In a process chamber 80 having a viewport 81, a lower electrode 83 serving as an upper electrode 82 and a stage is provided. A silicon wafer 84 is placed thereon. An AE sensor 85 is attached to the outer wall of the process chamber 80, and an optical sensor 86 is provided so as to face the Puport. Further, a voltage for electrostatic adsorption is applied from the ESC power supply 88 through various monitors 87 such as a reflected wave sensor, a current monitor, or an ESC monitor, and RF power is applied from the plasma power supply 89.

  RF power is applied between the upper electrode 82 and the lower electrode 83 to generate a plasma 90 to plasma process the silicon wafer 84. At this time, when the abnormal discharge 91 occurs, the abnormal discharge 91 is detected by the AE sensor 85 and the various monitors 87.

  However, both methods have a problem in detecting a weak abnormal discharge generated around the wafer placed on the electrostatic chuck. Conventional changes in plasma impedance and AE sensors are sufficiently sensitive to relatively large abnormal discharges that occur on the process chamber wall and wafer stage.

  However, the weak abnormal discharge of 1 mJ or less generated around the wafer during the 1 kW high-frequency plasma treatment has a problem in terms of insufficient and reliable detection. In an apparatus where the electrostatic chuck is acoustically weakly connected at the center of the lower part of the process chamber, the transmitted ultrasonic waves are greatly attenuated at the connecting part, so that the outer surface, upper surface or lower surface of the process chamber will be attenuated. The installed AE sensor cannot be detected.

  Also, even when strongly connected acoustically, in an apparatus connected at only one central part at the bottom of the process chamber, it propagates through only one connection part and reaches the AE sensor. There is no difference in the arrival time of the ultrasonic waves detected by the respective AE sensors. Therefore, the abnormal discharge of the plasma generated around the wafer of the electrostatic chuck has a problem that the place connected at the center of the lower surface of the process chamber is evaluated as the occurrence position of the abnormal discharge. As a result, damage to product wafers and damage to manufacturing equipment parts due to abnormal discharge occurring on the front, back, and periphery of the wafer placed on the electrostatic chuck are still occurring.

  In other words, the abnormal discharge that occurs around the wafer that has become apparent with further miniaturization of semiconductor devices largely depends not only on the plasma characteristics but also on the state of the wafer and the device structure formed on the wafer. Causing damage.

  Such abnormal discharge generated around the wafer is so weak that it cannot be detected by a conventional method or an AE sensor installed in a process chamber. For this reason, even if a wafer in the middle of manufacturing is damaged due to abnormal discharge, the wafer is sent to the next process as it is, which is a major factor in decreasing the manufacturing yield.

  As described above, unless the weak abnormal discharge generated around the wafer can be detected, the production of a large number of defective products cannot be suppressed, and there is a problem that the product yield as a whole line is remarkably reduced. Further, if such a weak abnormal discharge is left unattended, the most easily damaged electrostatic adsorption stage becomes seriously damaged, and a large amount of equipment maintenance costs are required.

  It is also conceivable to detect a weak abnormal discharge near the electrostatic chuck by directly attaching an AE sensor to the electrostatic chuck. However, the electrostatic chuck is generally used for the purpose of adsorbing a semiconductor substrate or a glass substrate. Then, by applying a predetermined voltage to the attracting electrode provided in the electrostatic chuck, an electric charge or electric field is formed on the surface of the electrostatic chuck, and these substrates are attracted by an electric force.

  When a substrate is processed using such an electrostatic chuck, the temperature of the substrate increases due to plasma processing, ion implantation, or the like. For example, in a plasma etching processing apparatus, the wafer temperature is about 200 ° C. during processing. Therefore, in order to detect abnormal discharge, it is necessary to attach an AE sensor for high temperature to the electrostatic chuck.

  Therefore, the present inventors detect weak abnormal discharge with high accuracy, stop the continuous production of defective products, and enable self-diagnosis of the most fragile electrostatic adsorption stage to enable high-temperature AE. A sensor built-in wafer stage with a built-in sensor has been proposed (see, for example, Non-Patent Document 1).

  FIG. 8 is a schematic configuration diagram of a plasma processing apparatus provided with a sensor built-in wafer stage proposed by the present inventor. The housing 103 is accommodated. A power application electrode 104 is provided in the stage housing 103 and joined to an electrostatic chuck 105 having an internal electrode. At this time, a concave portion of the power application electrode 104 is provided to embed the AE sensor 106, and a pressure is applied by a pressure application means (not shown). Reference numeral 108 denotes a stage shield.

  When RF power is applied to the voltage application electrode 104 from the RF power source 109, a plasma 110 is generated between the upper electrode 102 and the silicon wafer 107 adsorbed on the electrostatic chuck 105 is subjected to plasma processing. At this time, if a weak abnormal discharge occurs in the vicinity of the silicon wafer 107, the AE sensor 106 detects an AE wave having a frequency of 500 KHz or more.

  Further, when a wafer jump occurs due to an imbalance between the electrostatic adsorption force and the back surface cooling gas pressure, a sudden AE wave accompanying the wafer jump is also detected. In this case, since the frequency of the AE wave is a sound wave of several tens of KHz or less, it can be distinguished from an abnormal discharge that is an ultrasonic wave.

  FIG. 9 is an explanatory view of the advantages of the sensor built-in wafer stage. FIG. 9A is an output waveform of the built-in AE sensor when the outer wall of the process chamber is hit, and FIG. -It is an output waveform of the AE sensor attached to the outer wall of the chamber. As is apparent from the comparison of the figures, it can be seen that the built-in AE sensor does not detect the AE wave when the outer wall of the process chamber is hit.

  This means that the AE wave from the outer wall of the process chamber does not propagate to the wafer stage, and therefore, the built-in AE sensor can detect only a phenomenon near the wafer stage in a low acoustic noise environment.

Proceedings of the 60th JSAP Spring Meeting, 29a-B8-9, p.08-061, 2013.03.29

  However, it is not easy to insert a normal AE sensor into the wafer stage. For this reason, a method of inserting a thin AE sensor into the wafer stage has been studied. However, for reliable detection of weak ultrasonic waves, it is necessary to ensure adhesion with the electrostatic chuck.

  However, as a method of ensuring adhesion, there are means by adhesion and pressurization, but it is difficult to achieve uniformity, stability, and reproducibility of the pressurization, and as a result, weak abnormal discharge is increased. There is a problem that it is difficult to detect with high accuracy and reproducibility. This situation will be described with reference to FIG.

  FIG. 10 is an explanatory diagram of the pressure dependency of the sensitivity of the built-in sensor, and it can be seen that the detection sensitivity is greatly lowered when the pressure is insufficient in the frequency band of the AE wave generated due to abnormal discharge.

  In addition, as described above, a wafer jump or the like may occur in the process chamber. When the wafer jump occurs, it is difficult to perform an initial process. When such a wafer jump occurs, a weak vibration (sound wave) is accompanied. Therefore, detection of such a weak sound wave is also required.

  Accordingly, an object of the present invention is to accurately detect mechanical vibrations such as ultrasonic waves and wafer splashes accompanying weak abnormal discharge generated around a sample to be processed.

(1) In order to solve the above problems, the present invention resides in a sensor-integrated suction chuck device, a vacuum chuck having a suction mechanism, the opposite on the other side of the plane as the sample mounting surface of the suction chuck And an acoustic sensor having a laminated structure of a first conductive layer / piezoelectric layer / second conductive layer integrally formed on the side surface .

Thus, the first conductive layer / piezoelectric layer / second conductive layer integrally formed with respect to the opposite surface on the surface opposite to the sample mounting surface of the suction chuck provided with the suction mechanism. By providing an acoustic sensor having a laminated structure, the problem of process temperature is solved. Further, since it is not necessary to prepare a recess or the like for incorporating the acoustic sensor, the mechanical configuration is simplified, and no pressurizing mechanism is required. Furthermore, since it is possible to prevent the difference in the detection unit from occurring due to the integral formation, it is possible to detect a weak abnormal discharge or sample splash around the sample with high accuracy and good reproducibility.

(2) Further, according to the present invention, in the sensor-integrated suction chuck apparatus, the suction chuck having a suction mechanism, a cooling base member for cooling the suction chuck, and a surface of the suction chuck opposite to the sample mounting surface Alternatively, the first conductive layer / piezoelectric layer integrally formed on either one of the surfaces of the cooling base member on the opposite surface or the surface of the cooling base member / An acoustic sensor having a laminated structure composed of a second conductive layer.

  Thus, in the case of an adsorption chuck device having a cooling base member for cooling the adsorption chuck, such as a plasma processing apparatus, the acoustic sensor may be provided on the surface opposite to the sample mounting surface of the adsorption chuck. Alternatively, it may be provided on the surface of the cooling base member.

(3) Further, the present invention is characterized in that, in the above (1) or (2), the acoustic sensor has a laminated structure including a donut-shaped first conductive layer / piezoelectric layer / second conductive layer. To do. As described above, the acoustic sensor may have a laminated structure including a donut-shaped first conductive layer / piezoelectric layer / second conductive layer, and the lift pin is inserted into the hole of the donut.

(4) Also. The present invention is characterized in that, in the above (1) or (2), the acoustic sensor has a laminated structure including a plurality of first conductive layers / piezoelectric layers / second conductive layers separated from each other. As described above, the acoustic sensor may have a laminated structure composed of a plurality of first conductive layers / piezoelectric layers / second conductive layers separated from each other. It is possible to specify the abnormal part and the jumping part by obtaining the differential output between the laminated structure.

(5) Further, according to the present invention, in the above (1) or (2), the acoustic sensor includes a laminated structure including a first circular conductive layer / piezoelectric layer / second conductive layer, and the central circular shape. And a laminated structure comprising a concentric donut-shaped first conductive layer / piezoelectric layer / second conductive layer. As described above, the acoustic sensor includes a laminated structure composed of the first conductive layer / piezoelectric layer / second conductive layer having a central circular shape, and a donut-shaped first conductive layer / piezoelectric concentric with the central circular stacked structure. It may have a laminated structure composed of a body layer / second conductive layer, and the central circular laminated structure is used for differential, and the second conductive layer of the doughnut-shaped laminated structure is divided to obtain differential from a plurality of locations. An output can be obtained.

(6) Further, according to the present invention, in any one of the above (1) to (5), the piezoelectric layer may be any one of aluminum nitride, aluminum scandium nitride, gallium nitride, indium nitride, zinc oxide, or lithium niobate. It is characterized by having the maximum component.

  As described above, by using a piezoelectric body whose maximum component is aluminum nitride, gallium nitride, indium nitride, zinc oxide or lithium niobate as the piezoelectric layer, it is possible to reduce the film thickness and to improve heat resistance. This improves the degree of freedom of process conditions. Further, since the output voltage can be increased by dividing the piezoelectric layers and connecting them in series, a weak output can be amplified and reliably detected.

(7) Further, in the present invention according to any one of the above (1) to (6), the suction chuck is an electrostatic chuck provided with a suction electrode covered with an insulator as the suction mechanism. And As described above, the chuck is typically an electrostatic chuck including a chucking electrode covered with an insulator as a chucking mechanism, and can detect abnormal discharge and wafer jump.

(8) Further, the present invention is characterized in that, in the above (1) to (6), the suction chuck is a vacuum chuck provided with an intake mechanism as the suction mechanism. In this way, by mechanically forming the acoustic sensor on the vacuum chuck, it is possible to accurately detect mechanical weak vibrations such as wafer splashing.

(9) Further, the present invention is characterized in that in the processing apparatus, the sensor-integrated adsorption chuck device of any one of (1) to (7) is provided in a reaction vessel as a sample mounting mechanism.

(10) Further, in the above (9), the present invention is characterized in that the processing apparatus is a plasma processing apparatus of either a plasma etching apparatus or a plasma vapor phase growth apparatus, and the acoustic sensor is a superacoustic sensor. And Thus, when applied to a plasma processing apparatus, it is possible to accurately detect weak ultrasonic waves accompanying abnormal discharge by using a superacoustic sensor as an acoustic sensor.

(11) Further, the present invention is characterized in that the processing apparatus comprises the sensor-integrated suction chuck device according to (8) above as a sample mounting mechanism. In this way, by providing the sensor-integrated vacuum chuck in a processing apparatus such as a CVD apparatus or a spin coater apparatus, undesired mechanical vibrations can be detected with high accuracy.

According to the disclosed sensor-integrated adsorption chuck and processing apparatus, it is possible to accurately detect mechanical vibrations such as ultrasonic waves and wafer splashes accompanying weak abnormal discharge generated around the workpiece.

1 is a schematic configuration diagram of a sensor-integrated suction chuck device according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the sensor integrated electrostatic chuck apparatus of Example 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the plasma processing apparatus using the sensor integrated electrostatic chuck apparatus of Example 1 of this invention. It is a schematic block diagram of the sensor integrated electrostatic chuck apparatus of Example 2 of this invention. It is a schematic block diagram of the sensor integrated electrostatic chuck apparatus of Example 3 of this invention. It is a schematic block diagram of the sensor integrated electrostatic chuck apparatus of Example 4 of this invention. It is a schematic block diagram of the conventional plasma processing apparatus with an abnormal discharge detection mechanism. It is a schematic block diagram of the plasma processing apparatus provided with the sensor built-in type wafer stage proposed by the present inventors. It is explanatory drawing of the advantage of a wafer stage with a built-in sensor. It is explanatory drawing of the pressurization dependence of the sensitivity of the sensor incorporated in the wafer stage.

  Here, the sensor-integrated suction chuck according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a sensor-integrated suction chuck device according to an embodiment of the present invention. This sensor-integrated suction chuck device includes a suction chuck 10 having a suction mechanism and a first conductive layer 21 / piezoelectric layer 22 / first film integrally formed on a surface of the suction chuck 10 opposite to the sample mounting surface. An acoustic sensor 20 having a laminated structure composed of two conductive layers 23 is provided.

  The suction chuck may be an electrostatic chuck provided with an internal electrode 11 covered with a dielectric 12 or a vacuum chuck provided with an air inlet. In the case of a suction chuck device having a cooling base member for cooling the suction chuck 10 such as an electrostatic chuck provided in the plasma processing apparatus, the acoustic sensor 20 may be provided on the surface of the cooling base. In the case of an electrostatic chuck, the first conductive layer 21 and a third conductive layer 25 described later serve as a shield layer against RF power. A bias power supply 13 is applied to the internal electrode 11 via the extraction electrode 14.

  The acoustic sensor 20 may have a laminated structure including a donut-shaped first conductive layer 21 / piezoelectric layer 22 / second conductive layer 23, and a lift pin is inserted into the hole of the donut. The acoustic sensor 20 may have a laminated structure including a plurality of first conductive layers 21 / piezoelectric layers 22 / second conductive layers 23 separated from each other. By using one of them for differential, it is possible to obtain a differential output from another laminated structure and specify an abnormal part or a jump part.

  Alternatively, the acoustic sensor 20 includes a laminated structure composed of the first circular conductive layer 21 / piezoelectric layer 22 / second conductive layer 23, and a donut-shaped first conductive layer concentric with the central circular stacked structure. 21 / piezoelectric layer 22 / second conductive layer 23 may be used. In this case, it becomes possible to obtain differential outputs from a plurality of locations by dividing the electrode layer of the doughnut-shaped laminated structure by using the central circular laminated structure for differential. In addition, a lift pin passes through a hollow annular region between the central circular laminated structure and the donut shaped laminated structure.

  As the piezoelectric layer, a piezoelectric material having a maximum component of any one of aluminum nitride, aluminum scandium nitride, gallium nitride, indium nitride, zinc oxide, or lithium niobate having a thickness of 100 nm to 10 μm is preferable. To do. These piezoelectric bodies can be made thin, and the heat resistance is improved, so that the degree of freedom of process conditions is increased. Further, since the output voltage can be increased by dividing the piezoelectric layers and connecting them in series, a weak output can be amplified and reliably detected.

  Further, this laminated structure is covered with the third conductive layer 25 via the first insulator 24, and is entirely covered with the second insulator 26, and the ground extraction electrode 27 is drawn from the third conductive layer 25, The output extraction electrode 28 is extracted from the two conductive layers 23.

  As the dielectric 12, ceramics such as alumina, alumina / titania, aluminum nitride, zirconia, glass such as silica, or polymer such as polyimide is used. The internal electrode 11 is made of a metal such as tungsten or a tungsten alloy.

  In addition, the first conductive layer 21 and the third conductive layer 25 are formed by sputtering film deposition or vacuum deposition or the like with a metal having a thickness of 60 nm to 5 μm, a metal such as chromium, an alloy mainly composed of each of them. Film. As the second conductive layer 23, a metal such as titanium, titanium alloy, copper, aluminum, nickel or the like having a thickness of 60 nm to 15 μm, or an alloy mainly composed of each of them is used. As the first insulator 24, a film of alumina, a ceramic such as silicon nitride having a thickness of 60 nm to 15 μm, or a glass such as silica is formed by sputtering or ion plating. Alternatively, it is formed by printing, applying and curing a glass material. As the second insulator 26, a polymer such as polyimide having a thickness of 1 μm to 300 μm or a ceramic such as alumina is formed by sputtering film formation or thermal spraying.

  In addition, by providing the sensor-integrated adsorption chuck device in the reaction vessel as a sample mounting mechanism, a processing device that can detect weak abnormal discharge around the wafer and mechanical vibrations such as wafer splashing with high accuracy is configured. can do. As a processing apparatus, a plasma processing apparatus such as a plasma etching apparatus or a plasma vapor deposition apparatus is typical, but a processing apparatus such as a CVD apparatus or a spin coater apparatus equipped with a sensor-integrated vacuum chuck is also available. Target.

  As described above, in the embodiment of the present invention, the acoustic sensor including the piezoelectric layer integrally formed with the suction chuck is provided as the abnormality detection unit, so that the acoustic coupling is strong and the ultrasonic wave propagates well. Therefore, it is possible to detect and locate a weak abnormal discharge generated around the wafer. In addition, it is possible to detect mechanical vibration accompanying the wafer splash.

  As a result, it is possible to detect a weak abnormal discharge in the immediate vicinity of the work piece, so it is possible to stop many of the damaged products that have been problematic in the past, suppress the production of a large number of defective products, and significantly increase the product yield as a whole line. It becomes possible to improve.

  In addition, since it is possible to detect the occurrence of a malfunction before the apparatus is seriously damaged, the apparatus maintenance cost can be greatly reduced. In addition, since the location where an abnormality has occurred can be identified, an enormous amount of time required for investigating the location of the device failure is not required, and the device operating rate can be increased.

  Furthermore, it is possible to acquire completely new information such as signals related to ultrasonic waves in the immediate vicinity of the workpiece, making it possible to perform self-diagnosis of the most fragile electrostatic adsorption stage, thereby enabling the electrostatic adsorption stage. It becomes possible to optimize the replacement time of the.

  In addition, since deviations in process conditions can be detected, the reliability of the plasma processing process can be improved, and improvements in the processing conditions including the processing recipe can greatly reduce scraps and advance the plasma processing technology. . In addition, by using it as an important monitoring parameter for the operating state of the apparatus, it is possible to improve the overall apparatus maintenance and management technology.

  Specifically, for example, in the case of a flash memory manufacturing process on the latest large-diameter wafer, if a circuit abnormality occurs in one lot of wafers (25 wafers) with built-in circuits and increased added value, the loss amount Is enormous. Further, even when expensive chamber parts need to be replaced, they are similarly similarly damaged, and there is a possibility that these may occur simultaneously due to the occurrence of one abnormal discharge.

  However, if the sensor-integrated suction chuck device according to the embodiment of the present invention is used, the occurrence of abnormality can be detected on the spot in the production process, so that only one wafer can be damaged. The introduction of the sensor-integrated suction chuck device of the embodiment of the present invention is expected to significantly reduce the cost required for wafer damage and preventive replacement of expensive parts.

  Next, the sensor-integrated electrostatic chuck device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a schematic configuration diagram of the sensor-integrated electrostatic chuck device according to the first embodiment of the present invention. In this sensor-integrated electrostatic chuck device, the AE sensor 40 is formed integrally on the back surface of the electrostatic chuck 30 opposite to the wafer mounting surface.

  The electrostatic chuck 30 itself is the same as a conventional electrostatic chuck, and the periphery of a doughnut-shaped internal electrode 31 made of a tungsten alloy is covered with a coating dielectric layer 32 made of alumina ceramics. A bias power source 33 is connected through an extraction electrode 34.

  The AE sensor 40 is integrally formed by sequentially forming a film using a mask sputtering method. First, a first shield layer 41 made of a doughnut-shaped titanium alloy, a piezoelectric layer 42 made of AlN, and a sensor electrode 43 made of a titanium alloy are sequentially formed on the covering dielectric layer 32 on the back surface of the electrostatic chuck 30. In the figure, the piezoelectric layer 42 and the sensor electrode 43 have the same size, but actually, the sensor electrode 43 has a size inside the piezoelectric layer 42. Although not shown, an insertion hole through which the lift pin is inserted is provided in the core portion of the donut including the electrostatic chuck portion.

  Next, the piezoelectric layer 42 / sensor electrode 43 is covered with an inner covering insulating layer 44 made of alumina ceramic, and then covered with a second shield layer 45 made of a titanium alloy. At this time, the first shield layer 41 and the second shield layer 45 are electrically connected to provide a shield from RF power. Next, the whole is covered with an outer covering insulator layer 46 made of alumina ceramic, and a ground extraction electrode 47 and an output extraction electrode 48 are provided. When each layer is formed by sputtering, the openings corresponding to the ground extraction electrode 47 and the output extraction electrode 48 are covered with a mask, and the exposed end face of the opening of the conductive film is an outer covering insulator. Insulation is performed by the layer 46 or the like.

When an abnormal discharge occurs during the plasma processing, the voltage V _H1 is detected between the ground extraction electrode 47 and the output extraction electrode 48.

  FIG. 3 is a schematic configuration diagram of a plasma processing apparatus using the sensor-integrated electrostatic chuck apparatus according to the first embodiment of the present invention. The electrostatic chuck 30 integrated with the AE sensor 40 is made of a process chamber using silicone resin. Adhering to a cooling base fixed in 70. At this time, the output extraction electrode or the like is connected to an electric wire accommodated in the signal transmission cable 61.

  A coolant circulates inside the cooling base 60. Further, an AE signal pre-stage amplifier 62 is attached to the ceiling surface of the cooling base 60, and amplifies the AE signal transmitted via the signal transmission cable 61 and outputs the signal to the outside via the signal wire 64. Take out. A power supply wire 63 is also connected to the AE signal preamplifier 62.

  An upper electrode 71 serving as a ground electrode is provided on the ceiling surface of the process chamber 70, and discharge is generated between the lower electrode (wafer stage) to which the RF electrode is applied to generate plasma 73. The silicon wafer 72 adsorbed on the electrostatic chuck 30 is etched by plasma 73 or a film is formed.

  When a weak abnormal discharge occurs during plasma processing, the ultrasonic wave propagating through the electrostatic chuck 30 can be accurately detected by the AE sensor 40 integrally formed with the electrostatic chuck 30. Further, even when the silicon wafer 72 moves or bounces during the plasma processing, the movement can be detected as a sound wave. In addition, since the frequency differs between the ultrasonic wave accompanying abnormal discharge and the sound wave accompanying movement or splash, it can be detected separately.

  As described above, in the first embodiment of the present invention, since the AE sensor 40 is integrally formed directly on the back surface of the electrostatic chuck 30, it is possible to accurately detect a weak abnormal discharge or the like around the silicon wafer 72. it can. Further, there is no need to apply pressure to the AE sensor 40.

  Next, referring to FIG. 4, a sensor-integrated electrostatic chuck device according to a second embodiment of the present invention will be described. 4 is a schematic configuration diagram of a sensor-integrated electrostatic chuck device according to a second embodiment of the present invention, FIG. 4 (a) is a schematic cross-sectional view, and FIG. 4 (b) is a schematic plan view. . In this sensor-integrated electrostatic chuck device, the piezoelectric layer 42 of the AE sensor 40 integrally formed on the back surface opposite to the wafer mounting surface of the electrostatic chuck 30 is divided into five.

  The electrostatic chuck 30 itself is the same as the electrostatic chuck of the first embodiment, and the periphery of the internal electrode 31 made of tungsten alloy is covered with a coating dielectric layer 32 made of alumina ceramics, and the internal electrode 31 is interposed via the extraction electrode 34. Thus, a bias power source 33 is connected.

  The AE sensor 40 is integrally formed by sequentially forming a film using a mask sputtering method. First, a central shield and a first shield layer 41 made of a donut-shaped titanium alloy are provided on the covering dielectric layer 32 on the back surface of the electrostatic chuck 30. The annular portion between the central circle portion and the donut-shaped portion serves as an insertion point for the lift pin. Next, a piezoelectric layer 42 made of AlN and a sensor electrode 43 made of a titanium alloy are sequentially formed at five locations. In the figure, the piezoelectric layer 42 and the sensor electrode 43 have the same size, but actually, the sensor electrode 43 has a size inside the piezoelectric layer 42. In FIG. 4B, illustration of the sensor electrode 43 is omitted, and for convenience, the number is five, but the number is arbitrary.

  Next, the piezoelectric layer 42 / sensor electrode 43 is covered with an inner covering insulating layer 44 made of alumina ceramic, and then covered with a second shield layer 45 made of a titanium alloy. At this time, the first shield layer 41 and the second shield layer 45 are electrically connected to provide a shield from RF power. Next, the whole is covered with an outer covering insulator layer 46 made of alumina ceramic, and a ground extraction electrode 47 and an output extraction electrode 48 are provided.

  At this time, the output extraction electrode for the sensor electrode 43 in the central circle is the reference output extraction electrode 49 because the detection output from the central portion is low. When each layer is formed by sputtering, the openings corresponding to the ground extraction electrode 47, the output extraction electrode 48, and the reference output extraction electrode 49 are covered with a mask, and the exposed end face of the opening of the conductive film is covered. Is insulated by the outer covering insulator layer 46 or the like.

When abnormal discharge occurs during the plasma processing, voltages V _H1 , V _H2 , and V _L are detected between the ground extraction electrode 47, the output extraction electrode 48, and the reference output extraction electrode 49. Here, by using the detection voltage _VL of the reference output lead electrode 49 for differential, a differential output of (V _H1 −V _L ) and (V _H2 −V _L ) is obtained, so that the sensor with the largest output is obtained. It can be seen that abnormal discharge occurred in the vicinity of the electrode 43. That is, it is possible to detect not only the occurrence of abnormal discharge but also a rough occurrence position.

  As described above, in the second embodiment of the present invention, the piezoelectric layer and the sensor electrode are divided and provided at a plurality of locations, so that it is possible to specify a location where abnormal discharge occurs or a location where mechanical vibration occurs.

  Next, with reference to FIG. 5, a sensor-integrated electrostatic chuck device according to a third embodiment of the present invention will be described. FIG. 5 is a schematic configuration diagram of a sensor-integrated electrostatic chuck device according to a third embodiment of the present invention, FIG. 5 (a) is a schematic cross-sectional view, and FIG. 5 (b) is a schematic plan view. . In this sensor-integrated electrostatic chuck device, the piezoelectric layer 42 of the AE sensor 40 integrally formed on the back surface opposite to the wafer mounting surface of the electrostatic chuck 30 has a center circular portion and a donut-shaped portion, and sensor electrodes. 43 is divided into five.

  The electrostatic chuck 30 itself is the same as the electrostatic chuck of the first embodiment, and the periphery of the internal electrode 31 made of tungsten alloy is covered with a coating dielectric layer 32 made of alumina ceramics, and the internal electrode 31 is interposed via the extraction electrode 34. Thus, a bias power source 33 is connected.

  The AE sensor 40 is integrally formed by sequentially forming a film using a mask sputtering method. First, a central shield and a first shield layer 41 made of a donut-shaped titanium alloy are provided on the covering dielectric layer 32 on the back surface of the electrostatic chuck 30. The annular portion between the central circle portion and the donut-shaped portion serves as an insertion point for the lift pin. Next, a piezoelectric layer 42 made of AlN is provided in a similar shape to the central circle portion and the donut-shaped portion. Next, sensor electrodes 43 made of a titanium alloy are formed at five locations. In FIG. 4B, the sensor electrode 43 in the central circle is not shown, and five sensor electrodes 43 are shown for convenience, but the number is arbitrary.

  Next, the piezoelectric layer 42 / sensor electrode 43 is covered with an inner covering insulating layer 44 made of alumina ceramic, and then covered with a second shield layer 45 made of a titanium alloy. At this time, the first shield layer 41 and the second shield layer 45 are electrically connected to provide a shield from RF power. Next, the whole is covered with an outer covering insulator layer 46 made of alumina ceramic, and a ground extraction electrode 47 and an output extraction electrode 48 are provided.

  Here too, the output extraction electrode for the sensor electrode 43 in the central circle is the reference output extraction electrode 49 because the detection output from the central portion is low. When each layer is formed by sputtering, the openings corresponding to the ground extraction electrode 47, the output extraction electrode 48, and the reference output extraction electrode 49 are covered with a mask, and the exposed end face of the opening of the conductive film is covered. Is insulated by the outer covering insulator layer 46 or the like.

When abnormal discharge occurs during the plasma processing, V _H1 and V _H2 are provided between the ground extraction electrode 47 and each output extraction electrode 48, and V _L is provided between the ground extraction electrode 47 and the reference output extraction electrode 49. A voltage will be detected. Here, by using the detection voltage _VL of the reference output lead electrode 49 for differential, a differential output of (V _H1 −V _L ) and (V _H2 −V _L ) is obtained, thereby obtaining the largest output. It can be seen that abnormal discharge occurred in the vicinity of the sensor electrode 43. That is, it is possible to detect not only the occurrence of abnormal discharge but also a rough occurrence position.

  In the third embodiment of the present invention, since the piezoelectric layer is provided on almost the entire surface, it is possible to reliably detect any location where abnormal discharge occurs. However, the position detection accuracy is inferior to that of the second embodiment.

  Next, with reference to FIG. 6, a sensor-integrated electrostatic chuck device according to a fourth embodiment of the present invention will be described. FIG. 6 is a schematic configuration diagram of a sensor-integrated electrostatic chuck device according to a fourth embodiment of the present invention. In this sensor-integrated electrostatic chuck device, an AE sensor 50 is integrally formed on the surface of a cooling base 60.

  The electrostatic chuck 30 itself is the same as the electrostatic chuck of the first embodiment, and the periphery of the doughnut-shaped internal electrode 31 made of tungsten alloy is covered with a coating dielectric layer 32 made of alumina ceramics, and the internal electrode 31 is drawn to the extraction electrode. A bias power supply 33 is connected via 34.

  The AE sensor 50 is formed in one piece by sequentially forming a film using a mask sputtering method. First, the first insulator layer 51 made of alumina ceramics is formed on the surface of the cooling base 60 through which the signal transmission cable 61 is inserted, and then the first shield layer 52 made of a donut-shaped titanium alloy is formed. . Next, after forming a second insulator layer 53 made of alumina ceramics, a sensor electrode 54 made of a doughnut-shaped titanium alloy and a piezoelectric layer 55 made of AlN are sequentially formed.

  Next, the piezoelectric layer 55 is covered with a second shield layer 56 made of a titanium alloy, and then the whole is covered with an outer covering insulator layer 57 made of alumina ceramics. The output extraction electrode 58 is formed before the sensor electrode 54 is formed, and is connected to an electric wire provided in the signal transmission cable. Next, the electrostatic chuck 30 and the AE sensor 50 are pressure-bonded.

  Thus, in the fourth embodiment of the present invention, since the AE sensor 50 is integrally formed on the cooling base 60 side, the AE sensor 50 can be discarded even when the electrostatic chuck 30 is deteriorated and replaced. Instead, it is only necessary to replace the electrostatic chuck 30 portion, so that the cost can be reduced.

DESCRIPTION OF SYMBOLS 10 Adsorption chuck 11 Internal electrode 12 Dielectric 13 Bias power supply 14 Extraction electrode 20 Acoustic sensor 21 1st conductive layer 22 Piezoelectric layer 23 2nd conductive layer 24 1st insulator 25 3rd conductive layer 26 2nd insulator 27 Ground extraction Electrode 28 Output extraction electrode 30 Electrostatic chuck 31 Internal electrode 32 Covered dielectric layer 33 Bias power supply 34 Extraction electrode 40 AE sensor 41 First shield layer 42 Piezoelectric layer 43 Sensor electrode 44 Inner cover insulator layer 45 Second shield layer 46 Outer insulating insulator layer 47 Ground extraction electrode 48 Output extraction electrode 49 Reference output extraction electrode 50 AE sensor 51 First insulator layer 52 First shield layer 53 Second insulator layer 54 Sensor electrode 55 Piezoelectric layer 56 Second shield layer 57 Outer insulation layer 58 Output lead electrode 60 Cooling base 61 Signal transmission cable 62 AE signal pre-stage amplifier 3 Power supply wire 64 Signal wire 70 Process chamber 71 Upper electrode 72 Silicon wafer 73 Plasma 80 Process chamber 81 Viewport 82 Upper electrode 83 Lower electrode 84 Silicon wafer 85 AE sensor 86 Optical sensor 87 Various sensors 88 ESC power supply 89 Plasma Power supply 90 Plasma 91 Abnormal discharge 100 Process chamber 101 Viewport 102 Upper electrode 103 Stage housing 104 Power application electrode 105 Electrostatic chuck 106 AE sensor 107 Silicon wafer 108 Stage shield 109 RF power supply 110 Plasma

Claims (11)

A suction chuck with a suction mechanism;
An acoustic sensor having a laminated structure composed of a first conductive layer / piezoelectric layer / second conductive layer integrally formed on the surface opposite to the sample mounting surface of the suction chuck with respect to the opposite surface; A sensor-integrated suction chuck device having the same. A suction chuck with a suction mechanism;
A cooling base member for cooling the suction chuck;
With respect to either the surface opposite to the sample mounting surface of the suction chuck or the surface of the cooling base member on the surface opposite to the surface or the surface of the cooling base member And an acoustic sensor having a laminated structure composed of a first conductive layer / piezoelectric layer / second conductive layer integrally formed with each other.   The sensor-integrated suction chuck device according to claim 1, wherein the acoustic sensor has a laminated structure including a first conductive layer / piezoelectric layer / second conductive layer having a donut shape.   3. The sensor-integrated suction chuck device according to claim 1, wherein the acoustic sensor has a laminated structure including a plurality of first conductive layers / piezoelectric layers / second conductive layers separated from each other. .   The acoustic sensor includes a laminated structure composed of a central circular first conductive layer / piezoelectric layer / second conductive layer, and a donut-shaped first conductive layer / piezoelectric layer / concentric with the central circular laminated structure. The sensor-integrated suction chuck device according to claim 1, wherein the sensor-integrated suction chuck device has a laminated structure including a second conductive layer.   The sensor according to any one of claims 1 to 5, wherein the piezoelectric layer has any one of aluminum nitride, gallium nitride, indium nitride, zinc oxide, and lithium niobate as a maximum component. Integrated suction chuck device.   The sensor-integrated suction chuck according to any one of claims 1 to 6, wherein the suction chuck is an electrostatic chuck having a suction electrode covered with an insulator as the suction mechanism. apparatus.   The sensor-integrated suction chuck device according to any one of claims 1 to 6, wherein the suction chuck is a vacuum chuck having an intake mechanism as the suction mechanism.   8. A processing apparatus comprising the sensor-integrated adsorption chuck device according to claim 1 as a sample mounting mechanism in a reaction vessel. The processing apparatus is a plasma processing apparatus of either a plasma etching apparatus or a plasma vapor deposition apparatus,
The processing apparatus according to claim 9, wherein the acoustic sensor is an ultrasonic sensor.   A processing apparatus comprising the sensor-integrated suction chuck device according to claim 8 as a sample mounting mechanism.