JP2012084647A - Manufacturing method of semiconductor device and cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet cleaning method of a substrate which allows for efficient removal of pollution by foreign matters such as particles adhering to the substrate, and which allows for improvement in the yield of a product such as a semiconductor device.SOLUTION: When a wafer is cleaned by applying ultrasonic wave to a cleaning chemical, an arrangement direction of the wafer in the cleaning fluid for maximizing the cleaning efficiency is determined based on the distribution of the number of particles adhering onto the wafer before cleaning in the substrate, and the sound pressure distribution in an ultrasonic cleaning tank. The arrangement direction of the wafer thus determined is set for a wafer to be cleaned, and cleaning is performed while maintaining that arrangement direction in the cleaning fluid.

Description

  The present invention relates to a wet cleaning process for removing contamination mainly of particles adhering to the surface of a substrate, among semiconductor device manufacturing processes.

  In recent years, electronic devices, in particular, semiconductor integrated circuit devices, have been rapidly increasing their integration, speed, and functionality. In addition, a semiconductor substrate for forming a semiconductor integrated circuit device has also been increased in diameter. Along with this, the pattern dimensions of semiconductor elements constituting an integrated circuit have been miniaturized, and various new types of metal materials have been adopted in order to improve the characteristics. Under these circumstances, after the completion of the semiconductor product, particles such as metal particles that contaminate the substrate surface during the manufacturing process can be removed more efficiently than before by the cleaning process so that the manufacturing yield does not decrease. It is extremely important to prevent the occurrence of defects.

  For example, Patent Document 1 discloses an example of a cleaning processing method that improves the cleaning performance for particles in the cleaning process and improves the yield. FIG. 18 is a diagram showing the configuration of the cleaning processing apparatus described in Patent Document 1. In FIG. The cleaning tank 20 is filled with a cleaning liquid L such as a dilute hydrofluoric acid solution or a rinse liquid, and the wafer W is immersed in the cleaning tank 20 for cleaning. During the cleaning of the wafer W, a part of the cleaning liquid L is sucked from the inner tank 21 via the suction pipe 51 by the electric bellows pump 30 as a constant pressure feeding means, and mixed into the cleaning liquid L by the particle counter 50. It is possible to detect the amount of particles.

  When the particle counter 50 detects the number of particles equal to or larger than a predetermined amount, an alarm is displayed through the central processing unit (CPU) 60, and the cleaning liquid L in, for example, the cleaning tank 20 is discharged according to the result. Measures are taken such as supplying the cleaning liquid L into the cleaning tank 20 to prepare for the next cleaning process. In this way, the cleaning liquid is managed in an appropriate cleaning state to improve the cleaning performance and the yield.

JP-A-11-233478

  However, the cleaning method disclosed in Patent Document 1 has the following problems. In other words, the main cause in the cleaning process that directly affects the manufacturing yield of semiconductor integrated circuits and the like is particles adhering to the surface of the semiconductor substrate immersed in the cleaning chemical solution, as described above. In the cleaning method of Document 1, a part of the cleaning liquid is sucked and the number of particles in the cleaning liquid is measured with a particle counter. The number of particles obtained in this way is the number of particles in the cleaning liquid, not the number of particles adhering to the semiconductor substrate.

  The particles include, for example, fine particles of inorganic substances such as silicon, silicon oxide, and metal, and fine particles of organic substances, and these have various surface states and shapes. If the surface condition of the particles is different, the adsorption constant on the semiconductor substrate will be different, and there are some that preferentially adhere to the semiconductor substrate and some that do not, so the number of particles in the cleaning liquid is not necessarily the number of particles on the semiconductor substrate in the cleaning tank It is thought that it does not reflect the number.

  Further, in the method of sucking the cleaning liquid with a pump or the like as in Patent Document 1, the cleaning liquid is forcibly sucked into the pipe by the pressure of the pump, so that fine bubbles are likely to be generated in the cleaning liquid. There is a high possibility of detection, and the particle count itself may be inaccurate.

  As described above, the cleaning method performed by the method for managing the number of particles in the cleaning liquid estimates the particle contamination state of the semiconductor substrate from the number of particles in the cleaning liquid, and the number of particles to be measured is also precise. However, there was a limit to improving the cleaning power. In particular, for example, a semiconductor integrated circuit device manufactured using a CMOS process technology of 65 nm node or less or the like is required to further improve the cleaning power in order to improve the yield of a device including a semiconductor element having a fine dimension. .

  Also, in general, RCA cleaning using ammonia + hydrogen peroxide mixture, sulfuric acid + hydrogen peroxide mixture, hydrochloric acid + hydrogen peroxide mixture, and other chemicals such as acids, alkalis, surfactants etc. The cleaning method used has been employed to clean the substrate surface. Some cleaning chemicals accelerate the corrosion of these metal materials in situations where a wide variety of metal materials are used as the semiconductor integrated circuit device is miniaturized. Therefore, a highly efficient cleaning method is required even if the chemical solution concentration is reduced and the processing time is shortened.

  The present invention has been made to solve the above-described problems, and mainly provides a method for manufacturing a semiconductor device including a cleaning method capable of further improving the cleaning power in a wet cleaning process using a cleaning liquid. Objective.

  A first method of manufacturing a semiconductor device according to the present invention for solving the above-described problems shows a step of obtaining a distribution in the semiconductor substrate of the number of particles adhering to the surface of the semiconductor substrate, and a particle removing power in the cleaning liquid. A step of measuring a distribution of physical quantity values, at least a part of a region on the semiconductor substrate in which the number of particles is larger than the surroundings, obtained from the distribution of the number of particles in the semiconductor substrate, and the particles in the cleaning liquid A step of arranging the semiconductor substrate in the cleaning liquid so that at least a part of a region where the physical quantity value indicating the removal force is larger than the surrounding area, and maintaining the arrangement of the semiconductor substrate in the cleaning liquid, Cleaning the semiconductor substrate in a cleaning solution.

  In one form of the manufacturing method of the semiconductor device, the semiconductor substrate is cleaned by applying an ultrasonic wave to the cleaning liquid, and the physical quantity indicating the particle removal force in the cleaning liquid is set as the sound pressure of the ultrasonic wave.

  In another form of the method for manufacturing a semiconductor device, the cleaning liquid is a cleaning liquid having an etching property with respect to the surface of the semiconductor substrate, and a physical quantity indicating a particle removing force in the cleaning liquid is set as the cleaning liquid on the surface of the semiconductor substrate. The cleaning is carried out as the etching rate by.

  In still another embodiment of the method for manufacturing a semiconductor device, a physical quantity indicating a particle removing power in the cleaning liquid is a particle removal rate in cleaning the semiconductor substrate with the cleaning liquid.

  A second method of manufacturing a semiconductor device according to the present invention may be as follows. That is, in the first method of manufacturing a semiconductor device, the distribution in the semiconductor substrate of the number of particles adhering to the surface of the semiconductor substrate is calculated from the distribution in the semiconductor substrate related to the number of particles larger than the reference particle diameter and the reference particle diameter. It is composed of a distribution within a semiconductor substrate with respect to the number of small particles, and a physical quantity indicating the particle removal force in the cleaning liquid, the ultrasonic sound pressure in the cleaning liquid when ultrasonic waves are applied to the cleaning liquid, and the The etching rate of the surface of the semiconductor substrate in the cleaning solution by the cleaning solution is used.

  Then, at least a part of the region on the semiconductor substrate where the number of particles is larger than the surroundings, and the sound pressure in the cleaning liquid is larger than the surroundings, which is obtained from the distribution in the semiconductor substrate related to the number of particles having the reference particle size or larger. First cleaning is performed in which the semiconductor substrate is disposed in the cleaning liquid so as to overlap at least a part of the region, and the semiconductor substrate is cleaned in the cleaning liquid while applying the ultrasonic wave to the cleaning liquid while maintaining the layout. And at least a part of the region on the semiconductor substrate in which the number of particles is larger than the surroundings, and the etching rate in the cleaning liquid is determined from the process and the distribution in the semiconductor substrate related to the number of particles smaller than the reference particle diameter. The semiconductor substrate is placed in the cleaning solution so that at least a part of the larger region overlaps, and the placement is performed. By keeping to include a second cleaning step of cleaning the semiconductor substrate with the in the cleaning liquid.

  In the second method for manufacturing a semiconductor device, the first cleaning step and the second cleaning step can be performed simultaneously.

  In the first and second semiconductor device manufacturing methods, it is effective to use the cleaning liquid as a mixed liquid of ammonia and hydrogen peroxide. When applying ultrasonic waves to the cleaning liquid, it is desirable that the frequency of the ultrasonic waves be 20 kHz or more and 10 MHz or less.

  A third method of manufacturing a semiconductor device according to the present invention is the platinum deposited on the semiconductor substrate, wherein a silicide layer of nickel containing platinum is formed on a surface portion of the semiconductor substrate in the first method of manufacturing a semiconductor device. When the particles become the particles, at this time the cleaning solution is a diluted solution of a mixture of nitric acid and hydrochloric acid, the physical quantity indicating the particle removal force in the cleaning solution, the ultrasonic wave is applied to the cleaning solution, The semiconductor substrate is cleaned by applying ultrasonic waves to the cleaning liquid, using ultrasonic sound pressure in the cleaning liquid.

  More specifically, this manufacturing method is preferably applied to the case where the following configuration is provided. That is, the semiconductor substrate includes a gate electrode made of silicon formed thereon via a gate insulating film, a side wall made of an insulating film formed on a side wall of the gate electrode, and from below the side wall, A source / drain formed over the semiconductor substrate on both sides of the structure composed of the gate electrode and the sidewall; and the nickel silicide layer including platinum includes over the gate electrode and the source / drain Forming a nickel film containing platinum in the region; reacting the nickel film containing platinum with the surface of the source / drain by heat treatment to form a silicide layer of the nickel film containing platinum; and After the heat treatment, a step of selectively removing the unreacted nickel film containing platinum. Formed Te, the platinum particles are platinum particles remaining on the surface after the selective removal of the nickel film containing the platinum.

  Next, a cleaning apparatus according to the present invention for solving the above-described problems is provided with a cleaning tank for filling a cleaning liquid and immersing the substrate in the cleaning liquid for cleaning, and particles adhering to the surface of the substrate. The number of particles determined from the distribution of the number of particles in the substrate based on the distribution of the number of particles in the substrate and the distribution of the physical quantity value indicating the particle removal force in the cleaning liquid filled in the cleaning tank, The arrangement direction of the substrate is set so that at least a part of the region on the substrate that is larger than the periphery overlaps at least a part of the region that has a physical quantity value that indicates the particle removal force in the cleaning liquid that is larger than the periphery. And a transport mechanism for transporting the substrate into the cleaning liquid in the set arrangement direction.

  As a form of a mechanism for setting the arrangement direction of the substrate in the cleaning liquid of the cleaning apparatus, when the substrate is installed in the cleaning liquid by rotating from the reference arrangement direction of the substrate in the plane of the substrate, The cleaning efficiency for each rotation angle is calculated based on the distribution of the number of particles in the substrate and the distribution of the physical quantity value indicating the particle removal force in the cleaning liquid, and the calculated cleaning efficiency is equal to or greater than a predetermined value. A calculation unit that calculates a range of the rotation angle at the time, and a substrate rotation mechanism that rotates the substrate within the plane of the calculated rotation angle from the reference arrangement direction of the substrate. can do.

  In particular, when the substrate is a semiconductor substrate, the reference arrangement direction of the substrate in the cleaning liquid is such that the surface of the substrate is vertical in the cleaning liquid and the notch or orientation flat provided on the substrate is It is desirable that the direction be on a vertical line passing through the plane.

  In the cleaning apparatus according to the present invention, the cleaning tank may include an ultrasonic vibration plate that applies ultrasonic waves to the cleaning liquid, and the physical quantity indicating the particle removal force in the cleaning liquid may be an ultrasonic sound pressure. it can. Further, the cleaning device may include a measuring device that measures the distribution of the number of particles in the substrate, and a measuring device that measures a distribution of a physical quantity value indicating a particle removing force in the cleaning liquid.

  According to the present invention, it is possible to determine from the distribution in the substrate of the number of particles adhering to the surface of the substrate, the at least part of the region in the substrate where the number of particles is larger than the surrounding area, the ultrasonic sound pressure, and the cleaning liquid. Cleaning is performed by placing the substrate in the cleaning liquid so that at least a part of the region where the physical quantity value indicating the particle removal force in the cleaning liquid such as the etching rate is larger than the surrounding area overlaps. As described above, according to the present invention, a portion with a lot of particles on the substrate is exposed to a portion with a strong cleaning power in the cleaning liquid, so that the cleaning power can be further improved and the cleaning time can be shortened. The production yield can be improved.

The top view which shows the principal part structure of the washing | cleaning apparatus which concerns on this invention. Schematic which shows the structure of the foreign material inspection apparatus with which the washing | cleaning apparatus of FIG. 1 was equipped. Schematic which shows the structure of the wafer direction setting apparatus with which the washing | cleaning apparatus of FIG. 1 was equipped. Schematic which shows the structure of the chemical | medical solution washing tank with which the washing | cleaning apparatus of FIG. 1 was equipped. FIG. 3 is a cleaning process flow diagram illustrating a cleaning method according to the first embodiment of the present invention. The figure which shows the relationship between the coordinate system fixed to the chemical | medical solution washing tank, and the coordinate system fixed to the wafer installed in this chemical | medical solution washing tank. The figure which shows the example of number distribution of SiN fine particles adhering on a wafer. The figure which shows the example of the sound pressure distribution in the vertical surface of the ultrasonic wave in a chemical | medical solution washing tank. The figure which shows the example of the sound pressure distribution in the horizontal surface of the ultrasonic wave in a chemical | medical solution washing tank. The figure which shows the ultrasonic sound pressure dependence of the removal rate of SiN microparticles | fine-particles. The figure which shows the relationship between the calculated cleaning efficiency L and the rotation angle (omega) of a wafer. The figure which shows the SiN fine particle removal rate with respect to the cleaning method which concerns on the 1st Embodiment of this invention, and the conventional cleaning method. (A) Thermal oxide film etching amount dependence by cleaning chemical | medical solution of SiN fine particle removal rate, (b) The figure which shows the high etching rate area | region on a wafer. The figure which shows the SiN microparticle diameter dependence of the SiN microparticle removal rate by ultrasonic cleaning. Process sectional drawing which shows the salicide formation process of a MOS type semiconductor device. The figure which shows the residual Pt particle removal rate with respect to the cleaning method which concerns on the 4th Embodiment of this invention, and the conventional cleaning method. The figure which shows the problem with respect to the NiPtSi layer of the conventional cleaning method. The figure which shows the structure of the conventional washing | cleaning processing apparatus.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
<Configuration of cleaning device>
FIG. 1 is a plan view showing a main configuration of a cleaning apparatus for performing a cleaning method according to the first embodiment of the present invention. This cleaning device is designed to be able to clean a general substrate having a predetermined size, but here it is optimally configured for cleaning a semiconductor substrate (silicon single crystal wafer) used in a semiconductor integrated circuit device. It is assumed that This cleaning apparatus is used not only for the present embodiment but also for the cleaning process according to all embodiments described below. First, the cleaning apparatus will be described.

  In FIG. 1, a carrier loader 101 has a port in which carriers 102a and 102b for storing a plurality of wafers 103 to be cleaned can be installed. The carriers 102a and 102b are, for example, FOUPs and the like. Each wafer 103 can be stacked and accommodated in a groove-like slot provided in the carrier 102a and 102b. It can be transported between manufacturing equipment without external contamination. The carrier 102a stores a wafer 103 to be cleaned, and the carrier 102b stores a wafer for the next cleaning process of the carrier 102a and is in a standby state. The carrier loader 101 is provided with an infrared sensor (not shown). For example, when the carrier 102a is installed, the number of internal wafers and the slot position in which the wafers are stored can be determined.

  Although the side view of this cleaning apparatus is not shown in FIG. 1, only the carrier loader 101 and the carriers 102a and 102b are exposed to the clean room environment, and the other parts are almost not penetrated by external particles. Stored inside the housing.

  A processing preparation unit 104 that prepares for cleaning processing is provided adjacent to the carrier loader 101, and a foreign matter inspection unit 106 is provided adjacent to the processing preparation unit 104. The carrier 102a is in close contact with the load lock door 105 of the processing preparation unit 104. At the same time when the load lock door 105 is opened, the lid of the carrier 102a is opened, and the stored wafer is exposed to the processing preparation unit 104. The foreign matter inspection unit 106 is also provided with an open / close load lock door 107.

  The foreign matter inspection unit 106 includes a foreign matter inspection device 108 therein. FIG. 2 is a side view of the foreign matter inspection apparatus 108. A flat vacuum chuck 132 is attached to the tip of a rotatable support shaft 131 configured to be rotatable, whereby the wafer 103 is placed so that its rotational symmetry center and the rotation axis of the rotation support shaft 131 substantially coincide with each other. It can be fixed by suction. A laser light source 133 is installed above the wafer 103, and laser light 135 emitted from the laser light source 133 enters the wafer surface, and scattered light 136 reflected and scattered by particles on the wafer surface is detected by the detection device 134. Is done. The detection device 134 transmits the detection signal of the scattered light intensity to the cleaning control unit of the cleaning device described later through the signal line 137.

  The rotation support shaft 131 and the vacuum chuck 132 protrude upward from the bottom plate 130 of the foreign matter inspection unit 104 having a large opening, and can move two-dimensionally in the horizontal direction (xy direction). As a result, a spot of a predetermined size of the laser beam 135 scans on the surface of the wafer 103, and foreign matter (particles) can be detected over the entire surface of the wafer 103. Further, using the detection signal from the foreign substance inspection apparatus 108, the particle position coordinates on the wafer 103 and the particle diameter of the particles are calculated as numerical values by the arithmetic processing in the cleaning control unit.

  At the same time, the measurement date and time, measurement conditions, laser light 135 irradiation position, detection device 134 position, and the like are recorded for each wafer 103. The foreign matter inspection apparatus 108 is configured to be able to distinguish between particles and uneven color on the wafer 103 and to detect particles on the wafer on which the integrated circuit pattern is formed.

  A wafer direction setting device 109 (FIG. 1) is also provided in the processing preparation unit 104. FIG. 3 is a side view of the wafer direction setting device 108. A rotation support shaft 141 connected to a motor projects upward from a hole formed in the bottom plate 140 of the processing preparation unit 104, and a flat vacuum chuck 142 for attracting and fixing the wafer 103 is formed at the tip. The wafer 103 can be placed so that the rotational symmetry center thereof and the rotation axis of the rotation support shaft 141 substantially coincide.

  A notch (notch) detection device for the wafer 103 is provided, which includes an LED and a light emitting unit 143 and a light receiving unit 144 that are laser light sources across the end of the wafer 103, and light from the light emitting unit 143 is received by the light receiving unit 144. The notch position is detected based on whether light is received. Then, the rotation support shaft 141 is rotated using the detected notch position as a reference position, and the wafer 103 is rotated in a plane parallel to the surface by a predetermined angle to set the direction of the wafer 103. For controlling the rotation of the wafer 103 by the above angle, for example, based on a notch detection signal from the notch detection device transmitted to the control unit through the signal line 145, the control unit issues a command to rotate the rotation support shaft 141. Do.

  Although the notch detection device for detecting the notch of the wafer 103 has been described with reference to FIG. 3, when the wafer has an orientation flat, an orientation flat detection device configured to detect the flat portion may be used.

  A wafer cassette 110 is also installed in the processing preparation unit 104. The wafer cassette 110 receives the wafer 103 whose direction is set by the wafer direction setting device 109 while maintaining the direction, and horizontally stacks the wafers 103 with the surfaces of the plurality of wafers 103 facing each other. The processing preparation unit 104 further includes a first wafer transfer device 111. The first wafer transfer device 111 has a boat that supports the wafer 103, and supports the plurality of wafers 103 on the boat so that their surfaces are vertical, and the cleaning preparation unit 113 from the processing preparation unit 104. It can be conveyed to the cleaning processing unit 113 along the guide 112 installed over.

  In the above description, transfer and installation of the wafer 103 between the carrier 102a and the foreign matter inspection device 108, between the foreign matter inspection device 108 and the wafer direction setting device 109, and between the wafer direction setting device 109 and the wafer cassette 110 are not shown. 1 is performed by an articulated robot that is installed in an appropriate number in an appropriate position in the processing preparation unit 104 in FIG. 1 and has a support arm for the wafer 103 at the tip. Further, the transfer of the wafer 103 between the wafer cassette 110 and the first wafer transfer device 111 is performed by a transfer robot installed in the processing preparation unit 104 and having a function of changing the posture of the wafer 103 horizontally and vertically.

  The cleaning processing unit 113 is provided with chemical cleaning tanks 114 and 116, rinse tanks 115 and 117, and a drying tank 118. The chemical cleaning tanks 114 and 116 are tanks for cleaning the wafer with various acid or alkaline cleaning liquids. The rinsing tank 115 and the rinsing tank 117 are tanks for performing a rinsing process with pure water after the cleaning process in the chemical solution cleaning tanks 114 and 116, respectively. The drying tank 118 is a tank that performs pure wafer drying (IPA drying) without a watermark by replacing pure water remaining on the wafer surface by rinsing with IPA in, for example, IPA (isopropyl alcohol) vapor.

  The chemical solution cleaning tanks 114 and 116 may be filled with the same type of chemical solution or different types of cleaning chemical solutions depending on the purpose of cleaning. The chemical cleaning tanks 114 and 116, the rinsing tanks 115 and 117, and the drying tank 118 are usually made of transparent quartz or Teflon (registered trademark).

  In the cleaning processing unit 113, second wafer transfer machines 119, 121, and 123 corresponding to the chemical cleaning tanks 114 and 116 and the drying tank 118 are attached to the guide 125, and are movable along the guide 125. . These second wafer transfer devices 119, 121, 123 are connected to quartz wafer boats 120, 122, 124 that support the surfaces of a plurality of wafers substantially vertically, respectively. The wafer 103 transferred to the cleaning processing unit 113 by the wafer transfer device 111 is configured to be exchanged between the first wafer transfer device 111 and the three wafer boats 120, 122, and 124. Yes. The chemical cleaning, rinsing, and drying processes are performed by immersing wafer boats 120, 122, and 124 loaded with wafers in the processing tanks.

  Next, the chemical liquid cleaning layer 114 or 116 will be described in more detail. FIG. 4 is a diagram showing a configuration of the chemical solution cleaning layer 114 or 116 installed in the cleaning processing unit 113 of the cleaning apparatus of FIG. The cleaning inner tank 150 whose upper part made of quartz is opened is filled with the cleaning chemical solution 165, and the peripheral tank 151 made of the shallow quartz is cleaned so as to surround the upper periphery of the cleaning inner tank 150 over the entire circumference. It is welded to the inner tank 150 and attached. The pipe connected to the bottom surface of the peripheral tank 151 is connected to the pipe constituting the circulation line 159 via the valve 155, the circulation pump 156, the filter 157, and the in-line temperature controller 158. The circulation line 159 is connected to the inside of the cleaning inner tank 150. It is connected to a fixed quartz chemical solution discharge pipe 152.

  During the chemical cleaning process, the wafer 103 is supported by a wafer boat 167 (corresponding to 120 or 122 in FIG. 1) associated with the second wafer transfer device 119 or 121 and immersed in the cleaning chemical 165. Then, the circulation pump 156 pumps the cleaning chemical solution 165 by a constant amount per unit time, so that the cleaning chemical solution 165 overflows from the cleaning inner tank 150 to the peripheral tank 151, passes through the valve 155 and the circulation pump 156, and is removed from the surface of the wafer 103. Particles and other foreign matters that are separated and floated in the cleaning chemical 165 are removed by the filter 157, and further adjusted to a constant temperature by the in-line temperature controller 158. Thereafter, the cleaning chemical solution 165 is returned from the chemical solution discharge pipe 152 to the cleaning inner tank 150 and supplied. In this way, the cleaning chemical 165 circulates.

  In some cases, a part of the cleaning chemical 165 in the cleaning inner tank 150 is discarded from the waste liquid line (not shown), and then, for example, the valve 155 is closed and the valve 162 is opened to prepare the chemical in the chemical supply tank 160. The new clean cleaning chemical 165 is supplied from the chemical discharge pipe 152 to the cleaning inner tank 150 via the chemical supply pipe 161, the valve 162, the filter 157, the in-line temperature controller 158, and the circulation line 159.

  On the other hand, an outer cleaning tank 153 made of quartz or the like is provided outside the inner cleaning tank 150. Inside the outer cleaning tank 153, an ultrasonic vibration plate 164 is placed several mm to several centimeters below the bottom of the inner cleaning tank 150, and is arranged so as to be substantially parallel to the bottom surface of the inner cleaning tank 150. The cleaning chemical liquid 165 filled in the cleaning inner tank 150 via the liquid 166 serving as an ultrasonic transmission medium supplied from the liquid discharge pipe 154 into the cleaning outer tank 153 by applying ultrasonic vibration to the ultrasonic vibration plate 164 from the machine 163. Ultrasonic energy is applied to the.

  As the liquid 166, for example, deaerated water having a dissolved oxygen concentration of 1 ppm or less is suitable for improving the propagation efficiency of ultrasonic waves and increasing the sound pressure in the cleaning chemical liquid 165. The frequency of the ultrasonic wave applied to the ultrasonic vibration plate 164 is 20 kHz to 10 MHz, preferably 200 kHz to 5 MHz, more preferably 750 kHz to 3 MHz.

  Finally, in FIG. 1, a control unit 126 is provided at the right end of the cleaning device opposite to the carrier loader 101. The control unit mainly includes a central processing unit (CPU) (or a processing unit) and a storage device. The CPU performs all cleaning processing steps, that is, transfer / installation of the wafer 103, chemical cleaning processing, rinsing processing, and drying processing. Control flow and cleaning conditions. The storage device also includes measurement data acquired by the foreign substance inspection apparatus 108 such as the number of particles on the wafer, particle distribution and size thereof, basic data regarding the cleaning power distribution in the chemical cleaning layers 114 and 116, and the like. A processing execution program of the cleaning process, a calculation program related to cleaning, and the like are stored.

<Washing method>
The cleaning process according to the present invention can be performed using the cleaning apparatus of FIG. 1 described above. FIG. 5 is a flow chart of the cleaning process for explaining the cleaning method according to the first embodiment of the present invention. Hereinafter, the cleaning process method using the cleaning apparatus will be mainly referred to mainly with reference to FIGS. To explain. First, when the carrier 102a (FIG. 1) containing the wafer 103 to be cleaned is set on the carrier loader 101, the carrier 102a is opened at the same time as the load lock door 105 of the processing preparation unit 104 is opened.

  Next, after the load lock door 107 of the foreign substance inspection unit 106 is opened, it is installed in the processing preparation unit 104. The multi-joint robot (not shown) that has been described above takes out one wafer 103 from the carrier 102a and moves it through the transfer path a. After that, it is placed on the vacuum chuck 132 (see FIG. 2) of the foreign matter inspection apparatus 108 in the foreign matter inspection unit 106. At this time, the articulated robot can accurately place the wafer 103 so that the rotational symmetry center of the circular wafer 103 and the rotation axis of the rotation support shaft 131 of the foreign substance inspection apparatus 108 substantially coincide (step S1).

  The foreign matter inspection apparatus 108 scans with the laser beam 135 over the entire surface of the wafer 103 fixed to the vacuum chuck 132 by rotating the rotation support shaft 131 in the horizontal direction (xy direction) as necessary. The attached particles are detected and detected. The foreign matter inspection apparatus 108 calculates at least the position coordinates (x, y) and the particle size (unit: nm or μm) for the particles detected using an XY orthogonal coordinate system fixed on the surface of the wafer 103. These measurement data are transmitted to the control unit 126. The transmitted measurement data is stored in the storage device of the control unit 126 (step S2).

  In the storage device of the control unit 126, the entire surface of the wafer 103 is virtually divided into, for example, a large number of small rectangular unit sections, and section arrangement data arranged in a matrix and representative position coordinate data of the unit sections are stored. Yes. Therefore, the control unit 126 assigns the particle to the unit block where the particle exists based on the position coordinates of each particle acquired in step S2, and sets the number of particles per unit block (or may be a particle number density). Counting is performed to generate particle number distribution data in the wafer (step S3). The size of the unit section is preferably 5 mm to 10 mm square when a 200 mm diameter wafer is used, and preferably 10 mm to 15 mm square when a 300 mm diameter wafer is used.

  Next, when cleaning the wafer 103 with a chemical solution or the like, the control unit 126 increases the cleaning efficiency, that is, maximizes the cleaning efficiency and efficiently removes particles from the surface of the wafer 103. Alternatively, a calculation for obtaining the wafer arrangement direction (arrangement posture) in 116 is performed (step S4). This calculation will be described below.

  FIG. 6 shows the arrangement direction of the wafer 103 installed with the surface thereof supported vertically on the wafer boat 167 (see FIG. 4) in the cleaning chemical solution 165 filled in the chemical cleaning tank shown in FIG. It is a figure for demonstrating. The XY coordinate system is a coordinate system fixed in the surface of the wafer 103 with the rotational symmetry center of the circular wafer 103 as the origin O. The X′-Y ′ coordinate system is a coordinate system fixed to the chemical cleaning tank, the origin coincides with the origin O of the XY coordinate system, and the negative direction of the Y ′ axis is the downward direction.

  In order to execute the calculation in step S4, the reference arrangement direction of the wafer 103 is first determined. In the case of FIG. 6, this reference arrangement direction connects, for example, the notch P and the rotational symmetry center (origin O) of the wafer 103, and the line in the plane of the wafer 103 is vertical (vertical line). Therefore, the notch P is arranged in the downward direction. In general, instead of the notch P, an assumed point or straight line on the wafer 103 can be in a predetermined position as the reference arrangement direction of the wafer 103. The arrangement direction of the wafer 103 shown in FIG. 6 is a direction rotated counterclockwise by an angle ω with respect to the origin O in the plane of the wafer 103 from the reference arrangement direction.

In R _k are the k-th unit block that is set on the wafer 103, the position coordinates by defining the two diagonals of the intersection (the center of R _k) of the representative position of the unit blocks R _k example R _k are X- In the Y coordinate system, it is converted to polar coordinates (r _k , θ _k ), and in the X′-Y ′ coordinate system fixed to the chemical solution washing tank, it is polar coordinates (r ′ _k , θ ′ _k ), as is apparent from FIG. Is equivalent to (r _k , θ _k + ω). Point representing the position of the R _k may be any point in the R _k. Further, when the number of particles in the unit section calculated by the control unit 126 in step S3 is N _k with respect to R _k , N _k is constant in both the coordinate systems and does not depend on the coordinate system.

In the cleaning method according to the present embodiment, ultrasonic energy is applied to the cleaning chemical liquid 165 from the ultrasonic vibration plate 164 (FIG. 4) attached to the chemical cleaning tank in order to enhance the particle removal capability, thereby performing ultrasonic cleaning. However, the ultrasonic energy intensity or the sound pressure of the ultrasonic wave has a large or small distribution depending on the position inside the cleaning inner tank 150. In particular, a standing wave is generated in the cleaning chemical liquid 165 by a traveling wave from the ultrasonic vibration plate 164 toward the cleaning inner tank 150 and a reflected wave downward from the bottom surface of the cleaning inner tank 150 or the wafer boat 167 inside the cleaning inner tank 150. This is thought to be due to the tendency to form. Therefore, the sound pressure of the ultrasonic wave depends on the position in the cleaning inner tank 150, and the sound pressure A _k in the section R _k is expressed as A _k (r _k , θ _k + ω). Sound pressure A _k is large ultrasonic energy higher the value, the greater removal capacity of the particles.

  Therefore, the control unit 126 calculates a parameter called the cleaning efficiency L shown in the following formula (1) while increasing ω in steps of several degrees within a range of 0 ° ≦ ω <360 °, for example. N in the formula (1) is the total number of sections divided on the wafer 103.

  Next, the control unit 126 obtains a range of ω when the calculated cleaning efficiency L is equal to or greater than a predetermined value including the maximum value. Expression (1) is formed by the sum of the product of the number of particles and sound pressure in each unit section for each section, and the value of L is obtained when the unit section (region) position with many particles overlaps with the region position with high sound pressure. growing. This means that a section (region) to which many particles on the wafer adhere is exposed to a large sound pressure. Therefore, a large value of L means that many particles can be efficiently removed. Thus, the parameter L substantially represents the cleaning efficiency.

  In addition, calculating L while changing ω to obtain a range of ω where L is equal to or greater than a predetermined value means that the wafer 103 is rotated counterclockwise from the reference arrangement direction about the rotational symmetry center (origin O). This corresponds to calculating L and determining the wafer arrangement direction such that the cleaning efficiency L (particle removal efficiency) is a predetermined value or more. In other words, in general terms, at least a part of the area where the number of particles on the wafer is larger than the surrounding area and at least a part of the area where the sound pressure in the chemical cleaning tank or cleaning chemical liquid is larger than the surrounding area are placed in a standard arrangement. This is equivalent to obtaining the wafer arrangement direction in the cleaning chemical solution that is rotated from the direction to increase the cleaning efficiency. Note that when the calculated cleaning efficiency L has little dependency on ω and is equal to or less than a certain threshold, the control unit 126 sets ω = 0.

  After step S4 is completed as described above, the wafer 103 is placed on the vacuum chuck 142 of the wafer direction setting device 109 via the transfer path b (see FIG. 1) by a multi-joint robot (not shown). At this time, the articulated robot can place the wafer 103 horizontally such that the rotational symmetry center of the wafer 103 (the origin O in FIG. 6) and the rotation axis of the rotation support shaft 141 coincide. Thereafter, the wafer direction setting device 109 obtains the wafer 103 from the reference arrangement direction of the wafer 103 determined in advance by the wafer direction setting device 109 by the calculation in step S4 with the rotation axis of the rotation support shaft 141 as the center. An appropriate value in the range of the angle ω is selected and rotated by that ω (step S5).

Next, the wafer 103 is horizontally stored in the wafer cassette 110 (FIG. 1) through the transfer path c by an articulated robot (not shown). The reference arrangement direction of the wafer 103 when stored in the wafer cassette 110 is determined in advance. For example, as shown in FIG. 1, a direction in which a notch is formed at P ₀ on the side opposite to the wafer 103 insertion port side of the wafer cassette 110. It is. Then, the rotated wafer 103 is stored in the wafer cassette 110 while being rotated by a predetermined angle from the reference arrangement direction.

  Next, the control unit 126 determines whether or not a wafer to be cleaned remains on the carrier 102a (step S6). If there is a wafer to be cleaned, steps S1 to S6 are repeated for the wafer. It is. When the wafers 103 are thus removed from the carrier 102a, all the wafers 103 are temporarily stored in the wafer cassette 110. Next, the wafer 103 is maintained in the orientation direction after the rotation in step 5 by a transfer robot (not shown). The wafer is transferred to the first wafer transfer device 111 via the transfer path d, and is held with its surface vertical. The reference arrangement direction after the wafer 103 is held by the first wafer transfer device 111 is, for example, a direction in which the notch P is positioned vertically downward from the rotational symmetry center of the wafer 103.

  Further, the wafer 103 is transferred to the cleaning processing unit 113 via the transfer path e by the first wafer transfer device 111, and is transferred from the first wafer transfer device 111 to the wafer boat 120 of the second wafer transfer device 119, for example. The Next, the wafer 103 has the structure shown in FIG. 4 together with the wafer boat 120, and is immersed in a chemical cleaning tank 114 filled with the cleaning chemical, and a cleaning process using the chemical supplied with ultrasonic energy is performed (step). S7).

  In the wafer boat 120, the wafer 103 is arranged such that the origin O of the XY coordinate system fixed to the wafer 103 in the chemical cleaning tank 114 coincides with the origin of the XY ′ coordinate system fixed to the chemical cleaning tank 114. Can be immersed. In addition, the arrangement direction of each wafer 103 in the chemical solution cleaning tank 114 is maintained at an arrangement direction rotated by a predetermined angle from the reference arrangement direction by the wafer direction setting device 109, and the reference arrangement direction in the chemical solution cleaning tank 114 is maintained. Is the direction when the notch P is vertically downward as seen from the rotational symmetry center of the wafer 103 as described with reference to FIG.

  After completion of the chemical cleaning, the wafer 103 is rinsed with ultrapure water at room temperature in the rinsing tank 115, and then transferred into the drying tank 118 and dried. The chemical solution cleaning tank 114 itself is subjected to predetermined post-processing after the cleaning process is completed. In addition to ultrapure water at room temperature, the rinse liquid is functional water in which a gas such as hydrogen gas, helium gas, nitrogen gas, oxygen gas, argon gas, carbon dioxide gas is dissolved in ultrapure water or ultrapure water having a temperature higher than room temperature. Rinse water prepared by dissolving a small amount of ammonia or hydrochloric acid and adjusted in the range of pH 5 to 9, pure water applied with ultrasonic waves, or the like can be used.

  After the drying process, the wafer 103 is transferred again to the first wafer transfer device 111 and is transferred to the process preparation unit 104 via the transfer path f. Further, the wafer 103 is all stored in the carrier 102a waiting on the carrier loader 101 through the transfer path g by an unillustrated articulated robot, and the cleaning process is completed (step S8).

<Example of cleaning effect>
The cleaning method according to the first embodiment described above can be applied to cleaning processing of substrates having various surface states. Hereinafter, experimental examples relating to the effect of removing particles by this cleaning method will be described. The cleaning process basically followed the flow shown in FIG.

  The used wafer is a semiconductor substrate on which a silicon single crystal having a diameter of 200 mm is exposed on the entire surface, and the wafer surface is intentionally and forcibly contaminated with silicon nitride (SiN) fine particles having a particle diameter of 100 nm or more. Specifically, SiN fine particles are dispersed at a concentration of 100 ppm in a dipping tank filled with a liquid whose pH value is adjusted to 3 with hydrochloric acid, and the above-mentioned wafer from which the natural oxide film on the surface has been removed with hydrofluoric acid is dipped for 30 seconds. Thereafter, overflow rinsing with pure water was carried out for 10 minutes. In this way, a wafer having about 2500 SiN fine particles adhered to the surface was obtained. The SiN fine particles are regarded as particles.

  FIG. 7 shows the result of measuring the number distribution of SiN particles on the wafer before the cleaning process by the laser type foreign matter inspection apparatus as shown in FIG. The particle size detection sensitivity of the SiN fine particles of the foreign matter inspection apparatus is 0.1 μm or less. In FIG. 7, rectangular regions partitioned by a grid and arranged in a matrix form are unit sections having a size of 10 mm × 10 mm, and the numbers in the unit sections are obtained by the processing in step S3 of the cleaning process (FIG. 5). This is the number of SiN fine particles having a predetermined size or more existing in the unit compartment.

  As shown in FIG. 7, the distribution of the number of SiN particles is non-uniform, and a region A surrounded by a dotted line with a high number (or density) of SiN particles is located at the upper right of the wafer with the notch P as a reference. The region A is a region including a region where the number of SiN fine particles in the unit partition is set as a temporary threshold and a plurality of partitions equal to or greater than the threshold are concentrated.

On the other hand, FIG. 8 shows the measurement result of the sound pressure distribution inside the chemical cleaning tank when the chemical cleaning tank as shown in FIG. 4 is filled with the cleaning chemical and ultrasonic waves are applied thereto. The sound pressure distribution is a distribution in the vertical plane direction in the chemical cleaning tank, the sound pressure value is shown in arbitrary units such as W / cm ² and V (volt), and the dotted circle is the position of the wafer during the cleaning process. Indicates. For example, in the cleaning processing unit 113 of the cleaning apparatus shown in FIG. 1, the sound pressure includes a sound pressure probe in which a piezoelectric element such as PZT is attached in the vicinity of the tip of a sealed quartz tube, and the sound pressure probe in the cleaning chemical solution. It is possible to install a robot that can be moved in the vertical and horizontal planes after being immersed in the chemical solution washing tank, and this figure is also the result of measurement by such a measuring device.

  In the example of FIG. 8, there is a sound pressure distribution in the cleaning chemical, and there are three regions B where the sound pressure is particularly high. As described above, this is considered to be an effect of the standing wave of the ultrasonic wave. FIG. 10 is a diagram showing the sound pressure dependence of the SiN fine particle removal rate obtained in advance in a separate experiment. The removal rate is sharp when the sound pressure (arbitrary unit as in FIG. 8) is 0.5 or more. Therefore, the threshold value of the sound pressure for determining the high sound pressure region B in FIG. 8 can be set to 0.5 from the viewpoint of detergency. Based on this, a region B in FIG. 8 is a region including a region where high sound pressure with a threshold value of 0.5 or more appears in a concentrated manner.

  FIG. 8 shows the sound pressure distribution in the vertical plane, while FIG. 9 shows the sound pressure distribution in the horizontal direction in the chemical cleaning tank (cleaning inner tank 150), that is, the sound when the cleaning inner tank 150 is viewed from above. The pressure distribution measurement result is shown. An ultrasonic vibration plate 164 having a size close to the bottom area of the cleaning inner tank 150 is installed below the cleaning inner tank 150, and the wafer 103 is immersed with the surface vertical. In this example, there are three high sound pressure regions B even in a plan view, but the distribution in the direction perpendicular to the surface of the wafer 103 is almost uniform.

  11 shows the dependence of the cleaning efficiency L on the wafer rotation angle ω obtained by performing the calculation in step S4 of FIG. 5 based on the SiN fine particle number distribution measurement result of FIG. 7 and the sound pressure distribution shown in FIGS. It is a figure which shows sex. The definition of the rotation angle ω is the same as in FIG. 6, and ω is changed in steps of 4.5 ° during the calculation. The maximum value of the cleaning efficiency L is obtained when ω = 90 ° is rotated with respect to the reference arrangement direction of the wafer, but the allowable range of the cleaning efficiency L in the actual cleaning process is, for example, 70% or more of the maximum value. One of ω (the range sandwiched by the dotted line in FIG. 11) can be selected.

Moreover, the chemical | medical solution washing | cleaning conditions of FIG.5 S7 are as follows.
(1) Chemical cleaning tank; Chemical cleaning tank with the structure shown in Fig. 4
(2) Wafer; Rotate counterclockwise from the reference arrangement direction by the determined rotation angle ω (90 °) (step S5) and maintain the arrangement direction and immerse in the cleaning chemical.
(3) Cleaning chemical solution: ammonia + hydrogen peroxide solution mixture (APM), that is, NH ₄ OH (concentration 29 wt%) 5 liters + H ₂ O ₂ (concentration 31 wt%) 5 liters + H ₂ O (ultra pure water), volume Ratio 1: 1: 5, temperature 45 ° C
(4) Cleaning time: After the cleaning chemical temperature reaches 45 ° C, it is circulated for 5 minutes and then cleaned for 10 minutes by applying ultrasonic waves.

  FIG. 12 is a diagram showing the SiN fine particle removal rate obtained by the cleaning method according to this experiment and the conventional cleaning method. Here, the SiN fine particle removal rate was obtained from the difference between the number of SiN fine particles on the wafer before and after the cleaning process, measured by a foreign matter inspection apparatus. In addition, the conventional cleaning method does not take into account the SiN fine particle distribution and the ultrasonic sound pressure distribution on the wafer, and the wafer is simply placed in the cleaning chemical solution in the reference arrangement direction (the notch position is vertically downward from the rotational symmetry center of the wafer). It is immersed and cleaned by applying ultrasonic waves. As shown in FIG. 12, in the conventional cleaning method, the SiN fine particle removal rate is 42%, whereas in the cleaning method according to the present invention, the removal rate is 64%, which indicates that the cleaning performance is improved.

  The cleaning method of the present invention improves the cleaning ability even if the cleaning conditions are the same except for optimizing the wafer arrangement direction. Therefore, the conventional cleaning ability is maintained even if the cleaning chemical temperature is lowered from 45 ° C. to 40 ° C. and the cleaning processing time is reduced from 10 minutes to 5 minutes for the above example, thereby improving productivity. The manufacturing cost of electronic devices such as semiconductor integrated circuits can be reduced.

  Summarizing the above description, in the cleaning method according to the present embodiment, at least a part of a region including a region where the number of particles on the wafer is equal to or greater than a predetermined threshold, and a threshold value where the sound pressure of the ultrasonic wave is predetermined. Ultrasonic cleaning is performed after setting the wafer arrangement direction in the chemical cleaning tank so that at least a part of the region including the above region overlaps. The cleaning process embodying this is the flow shown in FIG. Thus, according to the present invention, the particle removal efficiency can be improved as described in the above experimental results.

  Normally, particles are present unevenly on the surface of the wafer. On the other hand, in batch immersion type cleaning equipment, the chemical flow is uneven due to the jig for holding the wafer in the chemical cleaning tank and the chemical supply pipe. Even if the wafer is immersed in the cleaning chemical solution as in the conventional cleaning method, the high particle contamination area on the wafer overlaps with the weak cleaning portion in the chemical cleaning tank. Removal of particle contamination was very difficult. Furthermore, it took a long time for cleaning to avoid this. However, according to the present invention, such a problem can be sufficiently solved.

(Embodiment 2)
Although the cleaning method according to the first embodiment uses the ultrasonic sound pressure distribution in the cleaning chemical, the cleaning method according to the second embodiment is replaced with the etching rate of the wafer surface by the cleaning chemical. The non-uniformity of the distribution depending on the position in the chemical cleaning tank is used. FIG. 13A is a diagram showing the relationship between the etching amount by APM of a silicon oxide film grown by thermal oxidation and the removal rate of SiN fine particles adhering to the silicon oxide film. APM is a mixture of NH ₄ OH (concentration 29 wt%): H ₂ O ₂ (concentration 31 wt%): H ₂ O = 1: 1: 5 (volume ratio) and a temperature of 45 ° C. The etching amount in the figure is obtained by changing the APM cleaning time of the thermal oxide film, and the SiN fine particle removal rate increases as the etching amount increases, indicating that the etching rate can be used as a physical quantity representing the cleaning ability. .

  FIG. 13B shows a case where the cleaning inner tank 150 of the chemical cleaning tank shown in FIG. 4 is filled with the above APM and the wafer 103 supported by the wafer boat 167 is cleaned without applying ultrasonic waves. FIG. 5 is a diagram showing a region C where the thermal oxide film etching rate is equal to or higher than a predetermined threshold value. The thermal oxide film etching amount distribution on the wafer 103 is 25 points at the center of the wafer 103 (within 65 mm from the center of the wafer 103) and the outer periphery of the wafer 103 (over 65 mm from the center of the wafer and within 5 mm from the edge of the wafer 103). It was determined from the measurement of the change in film thickness at 24 points.

  While the etching amount is 0.3 nm in the central portion of the wafer 103, the etching amount is as high as 0.33 nm in the region C close to the chemical solution supply pipe 152, and the etching rate distribution exists in the cleaning inner tank 150. Thus, FIG. 13A suggests that a high cleaning ability can be obtained in the region C where the etching amount is high. The cleaning process steps adopted by the cleaning method of the second embodiment using this are basically the same as those of the first embodiment (flow shown in FIG. 5), but only step S4 is changed. The steps will be described below, and description of the remaining steps will be omitted.

  First, after steps S1 and S2 in FIG. 5, step S3 is performed in which the number of particles (particle number density) per unit section divided and set on the wafer surface is counted to generate particle number distribution data in the wafer. . Thereafter, in step S4, the control unit 126 of the cleaning apparatus shown in FIG. 1 increases the parameter of the cleaning efficiency L shown in the following formula (2) by several degrees within a range of 0 ° ≦ ω <360 °, for example. To calculate.

Here, N _k is the number of particles (or particle number density) in the k-th unit section set on the wafer, ω is the rotation angle from the wafer reference arrangement direction, n is the total number of sections, and B (r _k , θ _k + Ω) is the wafer surface etching rate by the cleaning chemical at the kth unit partition position, and r _k and θ _k + ω are the representative position coordinates of the kth unit partition in the polar coordinate display expressed in the coordinate system fixed to the chemical cleaning tank. It is.

  Next, the control unit 126 obtains a range of ω when the calculated cleaning efficiency L is equal to or greater than a predetermined value including the maximum value. After completing step S4 in this manner, an appropriate value is selected from the obtained range of ω, and steps S5 to S8 are executed as in the first embodiment, and the cleaning process is completed. As can be understood from the cleaning process flow, the cleaning method according to the present embodiment has an effect of improving the cleaning ability with respect to the adhered particles on the wafer as in the first embodiment.

In this embodiment, the thermal oxide film is used to obtain the etching rate distribution as a physical quantity representing the cleaning power in the chemical cleaning tank. However, other insulating films such as PSG, BSG, BPSG, FSG (fluorine-doped Silicon oxide film), TEOS silicon oxide film, SiOC, CVDSiO ₂ , SiC, SiCN, SiON, SiN may be used.

(Embodiment 3)
The cleaning method according to the third embodiment uses the ultrasonic wave applied to the cleaning chemical solution and the particle removal characteristics by etching of the wafer surface with the cleaning chemical solution, and the distribution of the ultrasonic sound pressure and etching rate in the chemical cleaning tank. It is.

  The particle size of particles adhering to an actual wafer is not uniform and has a distribution. FIG. 14 is a diagram showing the dependency of the SiN particle removal rate on the SiN particle diameter when the wafer is immersed in a cleaning chemical solution and cleaned by applying an ultrasonic wave having a frequency of 1 MHz. In the case of ultrasonic chemical cleaning, the removal rate varies depending on the SiN particle size, indicating that relatively large particles having a particle size of 200 nm or more can be efficiently cleaned. The cleaning method according to the present embodiment uses this property. For particles larger than the reference particle diameter (for example, 200 nm) as a boundary, the removal efficiency is improved by ultrasonic energy. For small particles, the removal efficiency is improved by the wafer surface etching effect of the cleaning chemical.

  The cleaning method according to the present embodiment also employs the element steps of the cleaning process flow shown in FIG. 5, and the first cleaning method is as follows. First, after performing steps S1 and S2, step 3 is performed. In this step, the number of particles (particle number density) equal to or larger than the reference particle diameter is counted for each unit section divided and set on the wafer surface to generate the first wafer particle number distribution data, and for each unit section. Then, the number of particles (particle number density) smaller than the reference particle diameter is counted to generate second in-wafer particle number distribution data.

  Next, in step S4, the ultrasonic sound pressure distribution data in the chemical solution cleaning tank (for example, the cleaning inner tank 150 in FIG. 4), which is obtained in advance and stored in the storage device (for example, the storage device in the control unit 126 in FIG. 1), Using the wafer surface etching rate distribution data by the cleaning chemical solution in the chemical cleaning tank, the parameter of the cleaning efficiency L shown in the following formula (3) is set, for example, several times within the range of 0 ° ≦ ω <360 °. Increase to calculate.

Here N1 _k is the number of particles on the reference particle size or less in the k-th unit block on the wafer (or particle number density), N2 _k is smaller the number of particles than the reference particle diameter in the k-th unit block on the wafer (or particles Number density), ω is the rotation angle from the wafer reference arrangement direction, n is the total number of sections, A (r _k , θ _k + ω) is the sound pressure at the kth unit section position, B (r _k , θ _k + ω) Is the etching rate of the cleaning chemical at the position of the kth unit section, and r _k and θ _k + ω are the representative position coordinates of the kth unit section in the polar coordinate display expressed in the coordinate system fixed to the chemical cleaning tank. Next, the range of ω when the calculated cleaning efficiency L is equal to or greater than a predetermined value including the maximum value is obtained.

  After completing step S4 in this manner, an appropriate value is selected from the obtained range of ω, and steps S5 to S8 are executed similarly to the first embodiment to finish the cleaning process. As understood from the equation (3), the first cleaning method of the present embodiment is configured such that at least a part of a region including a region where the number of particles equal to or larger than the reference particle size is equal to or larger than a predetermined threshold is ultrasonic. At least part of the region including the region including the region where the sound pressure is equal to or greater than the predetermined threshold, and at least part of the region including the region where the number of particles smaller than the reference particle diameter is equal to or greater than the predetermined threshold. The cleaning process is performed by setting the wafer arrangement direction in the chemical cleaning tank so that at least a part of the region including the region where the etching rate of the cleaning chemical is equal to or higher than a predetermined threshold is maximized. Means.

If it is allowed to increase the number of steps in the cleaning process, the second cleaning method described below is also possible. That is, after performing steps S1 and S2 in FIG. 5, step S3 in the first cleaning method of the present embodiment is performed. Next, in step S4, first, the cleaning efficiency L1 is calculated using the equation (1) of the first embodiment. However using N1 _k in place of _{N k} In Equation (1). Then, the first range of ω when the calculated cleaning efficiency L1 is equal to or greater than a predetermined value including the maximum value is obtained. Next, the cleaning efficiency L2 is calculated using Expression (2) of the second embodiment. However using N2 _k in place of _{N k} In Equation (2). Then, the second range of ω when the calculated cleaning efficiency L2 is equal to or greater than a predetermined value including the maximum value is obtained.

  Thereafter, an appropriate value is selected from the obtained first ω range, the wafer is rotated by the selected rotation angle from the reference arrangement direction in step S5, and ultrasonic waves are applied to the cleaning chemical solution in step S7 through step S6. Perform the cleaning process. After step 7, the cleaned wafer is returned to the wafer direction setting device. Next, an appropriate value is selected from the second ω range obtained in step S4, the wafer is rotated by the selected rotation angle from the reference arrangement direction in step S5, and the cleaning process in step S7 is executed through step S6. . When this cleaning process is performed, the ultrasonic cleaning may or may not be performed. Then, after the cleaning process, step S8 is executed to finish the cleaning process.

  In the case of the second cleaning method described above, the number of steps is increased, but during the cleaning process, a wafer arrangement direction in which a region where many particles having a large particle diameter are present and a region where the ultrasonic sound pressure is large is superposed is superposed. The cleaning efficiency can be improved compared to the first cleaning method because the wafer arrangement direction in which the region where many particles having a small particle size are present and the region where the etching speed of the wafer surface by the cleaning chemical solution is superimposed can be realized independently. There are advantages.

  In the first to third embodiments described above, the ultrasonic sound pressure and the etching rate of the wafer surface by the cleaning chemical are used as the physical quantity indicating the particle removal force, but other physical quantities can be used. For example, it is the “particle removal rate” itself depending on the position in the chemical cleaning tank. The particle removal rate is obtained by, for example, cleaning a wafer having SiN fine particles distributed at a uniform density on the surface in a cleaning tank under a certain condition, and measuring a change in the number (or density) of SiN fine particles before and after the cleaning. Can be easily obtained together with the distribution in the wafer.

  Also, the cleaning device of FIG. 1 can be variously modified. For example, the foreign matter inspection unit 106 in FIG. 1 is a part of the cleaning device, but can be a separate foreign matter inspection device that is separate from the cleaning device. In this case, the measurement data regarding the particles can be transmitted to the cleaning apparatus main body via the network, and the controller 126 can perform various calculations.

(Embodiment 4)
The fourth embodiment of the present invention provides a method for manufacturing a semiconductor device including the cleaning method according to the present invention. FIG. 15 is a process sectional view for explaining the method for manufacturing a semiconductor device according to the fourth embodiment, and particularly shows a salicide forming process portion of the MOS type semiconductor integrated circuit device. The MOS type semiconductor integrated circuit device targeted by FIG. 15 is a device manufactured using a process of 60 nm node or less.

  First, the manufacturing process until the cross section of FIG. An element isolation region 171 in which a silicon oxide film or the like is embedded is formed in a predetermined portion of the semiconductor substrate (silicon substrate) 170 by, for example, an STI (Shallow Trench Isolation) method. Next, a gate insulating film 172 made of, for example, a thermally oxidized silicon oxide film having a thickness of 2 nm is formed on the semiconductor substrate 170 between the element isolation regions 171.

Next, a silicon film having a thickness of 100 nm is deposited on the entire surface including the gate insulating film by, eg, CVD (Chemical Vapor Deposition), and impurities are introduced by, eg, ion implantation. This silicon film is a film that becomes a gate electrode of a MOS transistor. In the case of an NMOS transistor, for example, phosphorus is introduced as an n-type impurity at an acceleration voltage of 15 keV and a dose of 1 × 10 ¹⁶ cm ⁻² . In the case of a PMOS transistor, for example, boron is introduced as a p-type impurity at an acceleration voltage of 5 keV and a dose of 5 × 10 ¹⁵ cm ⁻² . Thereafter, the silicon film is patterned by photolithography and dry etching to form a gate electrode 173.

Next, using the gate electrode 173 as a mask, impurities are introduced into the semiconductor substrate 170 on both sides of the gate electrode 173, for example, by ion implantation. In the case of an NMOS transistor, for example, arsenic is introduced as an n-type impurity at an acceleration voltage of 2 keV and a dose of 1 × 10 ¹⁵ cm ⁻² . In the case of a PMOS transistor, for example, boron is introduced as a p-type impurity at an acceleration voltage of 0.5 keV and a dose of 3 × 10 ¹⁵ cm ⁻² . As a result, a very shallow impurity region constituting the source / drain extension region 176 is formed.

  Next, an insulating film, for example, a 10 nm-thickness silicon oxide film and a 50 nm-thickness silicon nitride film, for example, are laminated and deposited on the entire surface of the semiconductor substrate 170 so as to cover the gate electrode 173. Thereafter, the silicon oxide film and the silicon nitride film deposited by, for example, RIE (Reactive Ion Etching) are anisotropically etched to form a sidewall 174 made of an L-shaped silicon oxide film on the side wall portion of the gate electrode 173 and silicon nitride. A sidewall 175 made of a film is formed.

Next, using the gate electrode 173 and the sidewalls 174 and 175 as a mask, impurities are introduced into the semiconductor substrate 170 on both sides of the structure constituted by the gate electrode 173 and the sidewalls 174 and 175, for example, by ion implantation. In the case of an NMOS transistor, for example, arsenic is introduced as an n-type impurity at an acceleration voltage of 20 keV and a dose of 5 × 10 ¹⁵ cm ⁻² . In the case of a PMOS transistor, boron, for example, is introduced as a p-type impurity at an acceleration voltage of 5 keV and a dose of 5 × 10 ¹⁵ cm ⁻² . As a result, a deep source / drain impurity region 177 is formed. Further, by performing a predetermined heat treatment, the impurities constituting the extension region 176 and the deep impurity region 177 of the source / drain are activated, and the source / drain is formed.

  Next, for example, a nickel (Ni) target to which platinum (Pt) is added is used on the entire surface including the gate electrode 173 whose upper surface is exposed, the extension region 176 whose surface is exposed, and the deep impurity region 177 of the source / drain. For example, a nickel film (NiPt film) 178 containing platinum having a thickness of 7 to 15 nm is deposited by sputtering. The composition ratio of Pt to the NiPt film in the target is, for example, 2 to 10 atomic% (atm%). Accordingly, the NiPt film 178 deposited from the target is configured with a certain composition ratio, but is hereinafter referred to as NiPt for convenience.

  Subsequently, a protective film 179 made of, for example, a titanium nitride (TiN) film having a thickness of 5 to 30 nm is formed on the NiPt film 178 by, eg, sputtering. This protective film 179 acts to prevent the NiPt film 178 from being oxidized in the subsequent process. The NiPt film 178 and the TiN film 179 may be continuously deposited using the same sputtering apparatus without opening to the atmosphere.

  Thereafter, as shown in FIG. 15B, heat treatment is performed, for example, at 200 to 400 ° C. for 30 seconds by, for example, RTA (Rapid Thermal Annealing). As a result, the constituent components Ni and Pt of the NiPt film 178 react with Si on the surface portion of the gate electrode 173, and simultaneously, the Ni and Pt react with Si constituting the surface portion of the source / drain. A NiPtSi layer 180, that is, a NiPt silicide layer is formed on the upper portion and mainly on the surface of the deep impurity region 177 of the source / drain (salicide forming step). The NiPtSi layer 180 has a certain composition ratio of Ni, Pt, and Si, but is expressed as NiPtSi for convenience.

  Next, as shown in FIG. 15C, the unreacted NiPt film 178 and the protective film 179 that did not react with Si after the heat treatment by RTA are wet-etched using a relatively high temperature chemical solution containing an oxidizing agent. The NiPtSi layer 180 is left and selectively removed. For example, a mixed solution of sulfuric acid and hydrogen peroxide (SPM solution: Sulfuric Acid-Hydrogen Peroxide Mixture) is used as the chemical solution containing the oxidizing agent. The volume percent concentration of sulfuric acid in SPM is, for example, 50 to 90%, and the volume percent concentration of hydrogen peroxide is, for example, 10 to 50%. In addition, for example, 1 to 69 wt% hot nitric acid water, 1 to 30 wt% hot hydrogen peroxide water, 1 to 200 ppm dissolved ozone water, and the like can also be applied.

  Here, the chemical solution for selective etching of the unreacted NiPt film 178 and the protective film 179 easily dissolves TiN and Ni, but it is very difficult to dissolve Pt. Next, cleaning for removing the remaining Pt particles is performed (FIG. 15C). The cleaning method according to the first embodiment of the present invention is applied to this cleaning, and processing is basically performed according to the flow shown in FIG. That is, for example, the cleaning apparatus shown in FIG. 1 is used, and steps S1, S2, and S3 are performed. In this case, almost all particles detected by the foreign substance inspection apparatus are residual Pt particles. Therefore, the particle distribution data in the wafer created in step S3 is distribution data of the number of residual Pt particles.

  Next, after steps S4, S5, and S6, cleaning is performed to remove residual Pt particles in step S7. For example, a chemical cleaning tank shown in FIG. 4 can be used for cleaning. In this case, the cleaning chemical solution 165 is a mixed solution of 69 wt% nitric acid: 36 wt% hydrochloric acid: ultrapure water, and a temperature of 40 ° C. is maintained by an in-line temperature controller 158, and 2 for stabilization of diluted aqua regia. After the time circulation holding, the semiconductor substrate 170 is immersed in the cleaning inner tank 150, and then ultrasonic waves are applied to the cleaning chemical solution 165 for cleaning for 5 minutes. During cleaning, the semiconductor substrate 170 is maintained in the cleaning inner tank 150 in the wafer arrangement direction set in step S5. After the cleaning is finished, the process is finished through step S8.

  The above is the method for manufacturing a semiconductor device according to the present invention. The silicide of NiPt used in this semiconductor device has a low resistance, has a large heat resistance and thermal stability compared to NiSi, and can easily control the formation of silicide on a microscale, so that a semiconductor integrated circuit having a dimension of 60 nm or less It is adopted as a silicide layer in the device. However, since there is a problem that residual Pt particles are generated in the manufacturing process as described above, it has been conventionally considered to remove with a strong acid such as aqua regia (volume ratio: nitric acid: hydrochloric acid = 1: 3).

  FIG. 17A is a SEM photograph of the NiPtSi layer surface after the unreacted NiPt film is selectively removed by SPM, and Pt particles remain in the circle. FIG. 17B is a schematic cross-sectional view in this state, and a thin silicon oxide film 181 is grown on the surface of the NiPtSi layer 180 where no residual Pt particles 182 are formed by oxidizing SPM. The silicon oxide film 181 is not grown directly under the Pt particle 182 because it is blocked by this particle.

  FIG. 17 (c) is a SEM photograph of the NiPtSi layer surface after the residual Pt particles are removed with aqua regia. The residual Pt particles are dissolved and removed by aqua regia, but the underlying NiPtSi layer is also dissolved. Damage has occurred. FIG. 17D is a schematic sectional view in this state. There is no abnormality in the region of the NiPtSi layer 180 covered with the thin silicon oxide film 181 having resistance to aqua regia. However, since chlorine in aqua regia is corrosive to Ni in the NiPtSi layer 180, the presence of residual Pt particles 182, Ni in the portion where the NiPtSi layer 180 is exposed becomes chloride ions and the NiPtSi layer dissolves. Thus, a recess 183 is generated.

  On the other hand, according to the cleaning method of the present invention, by using a diluted solution of pure water of nitric acid and hydrochloric acid as a cleaning chemical solution, corrosion / dissolution of the NiPtSi layer is suppressed and residual Pt particles are dissolved and removed without damage. can do. Although the solution of nitric acid and hydrochloric acid with pure water has a lower ability to dissolve residual Pt particles than aqua regia, the cleaning method of the present invention employs the flow shown in FIG. The semiconductor in the cleaning chemical solution so that the region including the region where the number of particles is equal to or greater than the predetermined threshold and the region including the region where the ultrasonic sound pressure in the cleaning chemical is equal to or greater than the predetermined threshold overlap. By performing the cleaning process by setting the substrate arrangement direction, it is possible to improve the mechanical removal capability of residual Pt particles. Thus, the cleaning method according to the present invention can sufficiently remove residual Pt particles.

  FIG. 16 shows a comparison of the residual Pt particle removal rate between the conventional cleaning method and the cleaning method of the present invention. However, the conventional cleaning method is a method in which the cleaning liquid and the cleaning time are the same as the cleaning method according to the present invention, and the arrangement direction of the semiconductor substrate in the cleaning chemical is not set. As shown in FIG. 16, according to the cleaning method of the present invention, residual Pt particles can be removed nearly three times after the conventional cleaning method.

  The cleaning method according to the present invention is not limited to the NiPt salicide forming process, but can be performed continuously after the foreign substance inspection process, for example, a cleaning process after ashing treatment for resist mask for ion implantation, and dry etching of the silicon film for gate electrode. The present invention can also be applied to a subsequent residue removal process, a cleaning process after film formation by a CVD method, and the like.

  The present invention is particularly effective for improving the cleaning efficiency of the wet cleaning process in the manufacture of semiconductor devices, but is also useful when used for cleaning plate-like bodies and other general objects.

DESCRIPTION OF SYMBOLS 101 Carrier loader 102a, 102b Carrier 103 Wafer 104 Process preparation part 105, 107 Load lock door 106 Foreign substance inspection part 108 Foreign substance inspection apparatus 109 Wafer direction setting apparatus 110 Wafer cassette 111 1st wafer conveyance machine 112, 125 Guide 113 Cleaning process part 114, 116 Chemical solution washing tank 115, 117 Rinse tank 118 Drying tank 119, 121, 123 Second wafer transfer machine 120, 122, 124, 167 Wafer boat 126 Control unit 130, 140 Bottom plate 131, 141 Rotation support shaft 132, 142 Vacuum chuck 133 Laser light source 134 Detector 135 Laser light 136 Scattered light 137, 145 Signal line 143 Light emitting part 144 Light receiving part 146 Bottom plate hole 150 Cleaning inner tank 151 Peripheral tank 152 Chemical solution discharge pipe 153 Cleaning outer tank 154 Liquid discharge pipes 155 and 162 Valve 156 Circulation pump 157 Filter 158 In-line temperature controller 159 Circulation line 160 Chemical liquid supply tank 161 Chemical liquid supply pipe 163 Oscillator 164 Ultrasonic vibration plate 165 Cleaning chemical liquid 166 Liquid 170 Semiconductor substrate 171 Element isolation region 172 Gate Insulating film 173 Gate electrode 174, 175 Side wall 176 Extension region 177 Deep source / drain impurity region 178 NiPt film 179 Protective film 180 NiPtSi layer 181 Silicon oxide film 182 Residual Pt particles 183 Recess

Claims (15)

Obtaining a distribution in the semiconductor substrate of the number of particles adhering to the surface of the semiconductor substrate;
A step of measuring a distribution of physical quantity values indicating the particle removing power in the cleaning liquid;
At least a part of the region on the semiconductor substrate where the number of particles is larger than the surroundings, and a physical quantity value indicating the particle removal force in the cleaning liquid, which is obtained from the distribution of the number of particles in the semiconductor substrate, is larger than the surroundings. Disposing the semiconductor substrate in the cleaning liquid so that at least a part of the region overlaps;
Maintaining the arrangement of the semiconductor substrate in the cleaning liquid and cleaning the semiconductor substrate in the cleaning liquid.   2. The semiconductor device according to claim 1, wherein the cleaning of the semiconductor substrate is performed by applying an ultrasonic wave to the cleaning liquid, and a physical quantity indicating a particle removing force in the cleaning liquid is a sound pressure of the ultrasonic wave. Production method.   The cleaning liquid is a cleaning liquid having an etching property with respect to a surface of the semiconductor substrate, and a physical quantity indicating a particle removing power in the cleaning liquid is an etching rate of the surface of the semiconductor substrate by the cleaning liquid. 2. A method for manufacturing a semiconductor device according to 1.   The method of manufacturing a semiconductor device according to claim 1, wherein the physical quantity indicating the particle removal force in the cleaning liquid is a particle removal rate in cleaning the semiconductor substrate with the cleaning liquid. The distribution in the semiconductor substrate of the number of particles adhering to the surface of the semiconductor substrate is a distribution in the semiconductor substrate with respect to the number of particles larger than a reference particle diameter, and a distribution in the semiconductor substrate with respect to the number of particles smaller than the reference particle diameter. ,
The physical quantity indicating the particle removal force in the cleaning liquid is an ultrasonic sound pressure in the cleaning liquid when an ultrasonic wave is applied to the cleaning liquid, and an etching rate of the surface of the semiconductor substrate in the cleaning liquid by the cleaning liquid. ,
At least a part of the region on the semiconductor substrate in which the number of particles is larger than the surroundings, and a region in the cleaning liquid in which the sound pressure is larger than the surroundings, obtained from the distribution in the semiconductor substrate regarding the number of particles having the reference particle diameter or more. A first cleaning step of disposing the semiconductor substrate in the cleaning liquid so that at least a part of the semiconductor substrate overlaps, and cleaning the semiconductor substrate in the cleaning liquid while applying the ultrasonic wave to the cleaning liquid while maintaining the disposition When,
At least a part of the region on the semiconductor substrate in which the number of particles is larger than the surrounding, which is obtained from the distribution in the semiconductor substrate regarding the number of particles smaller than the reference particle diameter, and the region in the cleaning liquid in which the etching rate is larger than the surrounding A second cleaning step of disposing the semiconductor substrate in the cleaning liquid so that at least a part of the semiconductor substrate overlaps, and maintaining the disposition and cleaning the semiconductor substrate in the cleaning liquid;
The method of manufacturing a semiconductor device according to claim 1, comprising:   6. The method of manufacturing a semiconductor device according to claim 5, wherein the first cleaning step and the second cleaning step are performed simultaneously.   The method for manufacturing a semiconductor device according to claim 1, wherein the cleaning liquid is a mixed liquid of ammonia and hydrogen peroxide.   The method of manufacturing a semiconductor device according to claim 2, wherein a frequency of the ultrasonic wave is 20 kHz or more and 10 MHz or less. The semiconductor substrate has a silicide layer of nickel containing platinum formed on a surface portion thereof,
The particles are platinum particles adhering to the semiconductor substrate;
The cleaning solution is a diluted solution of a mixture of nitric acid and hydrochloric acid,
The physical quantity indicating the particle removal force in the cleaning liquid is the sound pressure of the ultrasonic wave in the cleaning liquid when an ultrasonic wave is applied to the cleaning liquid.
The method of manufacturing a semiconductor device according to claim 1, wherein the cleaning of the semiconductor substrate is performed by applying an ultrasonic wave to the cleaning liquid. The semiconductor substrate includes a gate electrode made of silicon formed thereon via a gate insulating film, a side wall made of an insulating film formed on a side wall of the gate electrode, and the gate from below the side wall. A source / drain formed over the semiconductor substrate on both sides of a structure composed of an electrode and the sidewall;
The silicide layer of nickel containing platinum includes a step of forming a nickel film containing platinum in a region containing the gate electrode and the source / drain, and a surface of the nickel film containing platinum and the source / drain by heat treatment. And a step of forming a silicide layer of the nickel film containing platinum and a step of selectively removing the unreacted nickel film containing platinum after the heat treatment,
10. The method of manufacturing a semiconductor device according to claim 9, wherein the platinum particles are platinum particles remaining on the surface after the selective removal of the nickel film containing platinum. A cleaning tank for filling the cleaning liquid and immersing the substrate in the cleaning liquid for cleaning;
Based on the distribution in the substrate of the number of particles adhering to the surface of the substrate and the distribution of the value of the physical quantity indicating the particle removal force in the cleaning liquid filled in the cleaning tank, the number of the particles At least a part of the region on the substrate where the number of particles is larger than the surroundings, and at least a part of the region where the physical quantity value indicating the particle removal force in the cleaning liquid is larger than the surroundings, obtained from the distribution in the substrate. A mechanism for setting the arrangement direction of the substrates so as to overlap,
A cleaning apparatus comprising: a transport mechanism configured to transport the substrate into the cleaning liquid in the set arrangement direction.   The mechanism for setting the arrangement direction of the substrate in the cleaning liquid is the cleaning efficiency for each rotation angle when the substrate is rotated in the cleaning liquid from the reference arrangement direction of the substrate in the plane of the substrate. Is calculated based on the distribution of the number of particles in the substrate and the distribution of physical quantity values indicating the particle removal force in the cleaning liquid, and the rotation angle when the calculated cleaning efficiency is equal to or greater than a predetermined value. 12. A calculation unit that calculates a range, and a substrate rotation mechanism that rotates the substrate within a range of the calculated rotation angle within a plane of the substrate from a reference arrangement direction of the substrate. The cleaning apparatus according to 1.   The measurement device for measuring the distribution of the number of particles in the substrate, and the measurement device for measuring the distribution of a physical quantity value indicating the particle removal force in the cleaning liquid are further provided. Cleaning equipment.   The substrate is a semiconductor substrate, and the reference arrangement direction of the substrate in the cleaning liquid is such that the surface of the substrate is vertical in the cleaning liquid, and a notch or orientation flat provided on the substrate is within the surface of the substrate. The cleaning apparatus according to claim 12, wherein the cleaning apparatus is in a direction located on a vertical line passing through.   The said washing tank is provided with the ultrasonic vibration board which gives an ultrasonic wave to a washing | cleaning liquid, The physical quantity which shows the particle removal power in the said washing | cleaning liquid is the sound pressure of an ultrasonic wave of Claim 11-14 characterized by the above-mentioned. The cleaning apparatus according to any one of the above.