Abstract: The novel method allows monitoring of nitrogen processes by making use of the fact that the incorporation of nitrogen near the surface in silicon, or in a thin silicon nitride layer on the silicon surface, inhibits the diffusion of oxygen during the subsequent thermal oxidation. Accordingly, the oxidation rate of the thermal oxidation is reduced and the growth of the oxide layer on the silicon surface is inhibited. The thickness of the oxide layer is thus used as a measure for the nitrogen content, i.e., for the quality of the nitrogen process.

Abstract: A system and method for detecting and preventing arcing in plasma processing systems. Arcing is detected and characterized by measuring and analyzing electrical signals from a circuit coupled to the plasma. After characterization, the electrical signals can then be correlated with arcing events occurring during a processing run. Information can be obtained regarding location, severity, and frequency of arcing events. The system and method better diagnose the causes of arcing and provide improved protection against undesirable arcing, which can cause damage to the system and the workpiece.

Abstract: The invention relates to a method and a device for regulating the thickness of coatings or layers, in particular of bond coatings, wherein bonding is controlled in a programmed manner thereby taking into account the influence of disturbance variables. The invention can be used especially in the production of DVDs. The advantages of the present invention are reproducible accuracy in adjusting the thickness of the coating/bond coating and thus an increased production output.

Abstract: A multiple head dispensing system and method is provided. In one embodiment, a dispensing system for dispensing material onto a substrate includes a plurality of independently operable dispensing heads, and a conveyor system, disposed beneath the plurality of dispensing heads, having a first track and a second track, each of which is constructed and arranged to convey substrates to working positions beneath the dispensing heads. The dispensing system may include a plurality of gantry systems, each of which is coupled to one of the plurality of independently operable dispensing heads.

Abstract: A spreading state of an outline of the outer periphery of a coating solution is detected by a detecting sensor, and the rotation speed or the like of a wafer as a substrate is controlled so that a spreading speed of the outline becomes not more than a predetermined speed with no danger of producing a scratchpad. Alternatively, the width in the radius direction of a scratchpad is measured, and the rotation speed or the like of the wafer is controlled so that the width in the radius direction becomes not more than a predetermined value. Thereby, occurrence of the scratchpad is prevented or the degree thereof is decreased, thereby avoiding uncoating of the coating solution on the substrate and reducing the amount of the coating solution used.

Abstract: An electron-emitting device having an electroconductive film including an electron-emitting region arranged between a pair of device electrodes is manufactured. The electroconductive film is formed by applying a liquid containing the material of the film to a substrate by using an ink-jet method, then drying and heating the applied liquid. Defective conditions, if any, in the applied liquid or the precursor film formed by drying the liquid or the electroconductive film formed by heating the precursor film are detected and remedied by applying the same liquid again to the area detected for a defective condition. The detection and remedy of any defective condition may be conducted after the liquid-applying, drying or baking step.

Abstract: A pure metal is vaporized in a receiver, and a quantity of oxygen slightly substoichiometric for the oxide is introduced. To determine the thickness of the layer deposited on the film and to control the vaporization rate, optical sensors are installed in an area where the layer, because of the presence of unoxidized metal, has sufficient absorption for optical measurement. After the determination of the transparency by the sensors, the layer is subjected to a secondary oxidation process.

Abstract: A coating film forming apparatus comprising a coating solution supplying unit which supplies a coating solution to a rotating substrate, a memory which stores a first correlation between an atmospheric pressure and a film thickness of the coating film formed on the substrate, and a second correlation between a film thickness and a rotation speed of the substrate, an atmospheric pressure detector which detects an actual atmospheric pressure, a film thickness computation unit which computes an actual film thickness of the coating film from the actual atmospheric pressure based on the first correlation, and a rotation speed control unit which obtains a corrected rotation speed of the substrate based on the second correlation and a difference between the actual film thickness and a target film thickness, and rotate the substrate at the corrected rotation speed.

Abstract: Fabricating graded index plastic optical fiber by diffusing a high molecular weight dopant within a step index plastic optical fiber after the step index plastic optical fiber has been drawn from a preform using a conventional draw tower in a first embodiment. Also, the step index plastic optical fiber may be fabricated by extruding one material circumferentially around another material, e.g., by use of a concentric nozzle. The dopant is diffused after the drawing or extruding of the step index plastic optical fiber by heating the plastic optical fiber to a temperature that causes a high rate of diffusion state while measuring the transmission bandwidth of the plastic optical fiber. When the predetermined specified transmission bandwidth is measured, the plastic optical fiber is immediately returned to an ambient temperature. In addition, the plastic optical fiber may be gradually heated to an equilibrium temperature that is just below the temperature required to produce the high rate of diffusion state.

Abstract: A method for producing a metal layer with a given thickness includes the step of measuring an electrical resistance of the metal layer via connections on a starting layer provided under the metal layer. The resistance measurement is performed during or after the deposition of the metal layer. The layer thickness of the deposited metal layer is determined from the resistance measurement. Depending on the thickness of the already deposited metal layer, the deposition process is continued or repeated until a metal layer with a desired thickness is produced.

Abstract: The disclosure relates to an apparatus for electrostatically adhering grains to a planar substrate comprising:

Abstract: An ozone-processing apparatus for a semiconductor process system includes an airtight process chamber and a lamp chamber, which are partitioned by a window for transmitting ultraviolet rays. A plurality of ultraviolet-ray lamps is arrayed along the window in the lamp chamber. A measurement space is defined between the window and the lamps in the lamp chamber. The lamp chamber is provided with a mount portion to set up a measuring unit therein. The measuring unit includes a sensor to be inserted into the measuring space, for measuring the light quantity of the lamps. The sensor is movable in a direction in which the lamps are arrayed.

Abstract: In forming a resist film by supplying a resist liquid onto a surface of an LCD substrate loaded in a rotation cup, a coating liquid is coated on the surface of the substrate by spraying the resist liquid onto the surface thereof while not rotating the substrate to thus form the coating film on the overall surface of the substrate, then the substrate is sealed into the rotation cup by closing the processing vessel by a lid member, and then a film thickness of the coating film is regulated by rotating the rotation cup and the substrate.

Abstract: System and method for determining thermal characteristics, such as temperature, temperature uniformity and emissivity, during thermal processing using shielded pyrometry. The surface of a semiconductor substrate is shielded to prevent interference from extrinsic light from radiant heating sources and to form an effective black-body cavity. An optical sensor is positioned to sense emitted light in the cavity for pyrometry. The effective emissivity of the cavity approaches unity independent of the semiconductor substrate material which simplifies temperature calculation. The shield may be used to prevent undesired backside deposition. Multiple sensors may be used to detect temperature differences across the substrate and in response heaters may be adjusted to enhance temperature uniformity.

Abstract: The present invention is a method and apparatus for repairing a coating defect. The apparatus includes a utility disk holder being mounted to a frame. The rotary disk contains a plurality of toolholes with a plurality of corresponding notches. A plurality of tools can be removeably secured to the plurality of toolholes. Each tool can be rotatably used to cure the coating defect.

Abstract: In a method of direct or indirect application of a liquid or viscous coating medium onto a moving material web, specifically a paper or cardboard web, a layer of the coating medium is applied to the material web by use of an applicator unit. The coating result is then checked for deviations from the desired coating result. In the event that such deviations are detected, and in order to correct them, at least one applicator unit operating parameter is adjusted. The adjustment is made within a short time period, and with the material web running, from an initial operating parameter value that is in effect prior to detection of the deviation. Subsequently, the operating parameter is then reset to at least approximately the initial parameter value, whereby the adjustment and the subsequent resetting may be repeated if necessary.

Abstract: A method of fabrication and inspection includes depositing a coating and determining at least one physical property of the coating using eddy current techniques. In a detailed embodiment an abradable coating having a metal volume fraction in the range of from 0.3 to 0.5 is applied to an inner circumference of a stator for a gas turbine engine compressor. The eddy current probe is positioned by a manipulator. A distance separating the probe and a surface of the coating is measured using a frequency above one megahertz (MHz). The thickness of the coating is measured by determining the rolloff frequency for the coating's complex impedance. The coating density is determined by its complex impedance at a characteristic frequency below four MHz. The density can be used as an indication of the performance of the coating with respect to abradability and the erosion resistance. The measurements may also be applied as a post-process quality control technique.

Abstract: A system for evaluating the reflectance of an object (e.g., a CRT) that is coated with an anti-reflective coating material is disclosed. The quality and/or uniformity of the coating is evaluated by a reflectometer. The reflectometer is positioned relative to the object by non-contact sensors. Reflectance data gathered by the reflectometer is analyzed to determine to what extent the actual coating differs from the optimal (i.e., ideal) coating. A feedback system modifies the coating process for subsequent objects in an attempt to fine-tune the coating process and achieve optimal anti-reflective coatings.

Abstract: The invention generally relates to various aspects of a plasma process, and more specifically the monitoring of such plasma processes. One aspect relates in at least some manner to calibrating or initializing a plasma monitoring assembly. This type of calibration may be used to address wavelength shifts, intensity shifts, or both associated with optical emissions data obtained on a plasma process. A calibration light may be directed at a window through which optical emissions data is being obtained to determine the effect, if any, that the inner surface of the window is having on the optical emissions data being obtained therethrough, the operation of the optical emissions data gathering device, or both. Another aspect relates in at least some manner to various types of evaluations which may be undertaken of a plasma process which was run, and more typically one which is currently being run, within the processing chamber.

Abstract: During the application of a roll coating on a metal substrate, using double contactless measuring sensors (1, 3), inductive, and for instance optical or capacitive, the method consists in effecting, before application, at least a double distance measurement over a strip zone not yet coated, then, effecting, after application, at least another double distance measurement over approximately the same zone already coated, and the thickness of the applied coating is deduced from the double measurements before application and after application. The invention is applicable to the measurement of thickness, on ferromagnetic substrates, of non solidified coatings, in particular liquid or pasty and to the adjustment of thickness in installations with corresponding coatings.

Abstract: An apparatus for manufacturing plug and the manufacturing method is described. The method comprises providing a baseplate on a bottom surface of a sealed printing chamber. The printed circuit board and a stencil on the baseplate are sequentially mounted on the baseplate. Several cameras are used to align the holes of the printed circuit board and the stencil. A proper amount of preheated paste is printed on the stencil. The sealed printing chamber is adjusted to a first pressure to perform a paste-printing step for filling the hole of the printed circuit board with paste. The sealed printing chamber is adjusted to a second pressure. The sealed printing chamber is adjusted to a third pressure to perform a scraping step for remove redundant paste.

Abstract: An object is to provide a method of monitoring a CVD liquid source for forming a thin film having a high dielectric constant, which allows detection of the concentration abnormality and the deterioration of the CVD liquid source. First, the CVD liquid source used as a sources of chemical vapor deposition is prepared by dissolving an organometallic compound of dipivaloyolmethane type in an organic solvent. Secondly, a spectroscopy of the CVD liquid source is performed.

Abstract: The present invention is to produce a ceramic green sheet with an even thickness. By supplying a ceramic slurry to a slurry room comprising a slurry coater, contacting a carrier film to the fringe part of an opening of the slurry room with pressure so as to close the opening, and moving the carrier film along the opening in the state, a ceramic green sheet made from the slurry can be formed on the carrier film. At the time, based on the actual flow rate data on the actual flow rate of the slurry measured by the flow meter and the actual thickness data on the actual thickness of the green sheet measured by the film thickness meter, appropriate flow rate data on the appropriate flow rate of the slurry to be supplied for obtaining a green sheet with a desired thickness are sought in an appropriate flow rate data calculating means so that the flow rate of the slurry is controlled by the flow rate controlling means based thereon.

Abstract: A method of coating optical substrates with anti-reflection (AR) coatings is described. The thickness and composition of the coating is determined by minimizing the product of the Fresnel reflection coefficients for a coating with the angular- and wavelength-dependent sensitivity of the human visual system to minimize the perceived reflectance for the coated article. A compact chamber is evacuated and flushed with chemically inert gas such as argon or nitrogen. One or more molecular precursors are deposited using plasma enhanced chemical vapor deposition (PECVD) to form AR films. Single-layer AR coatings based on fluoropolymer films of controlled thickness, as well as organic, organosilicon, and/or inorganic multilayers are described. Also provided is a method for monitoring film growth optically, using a polarized, light-emitting diode, a polarizing optical filter, and a photodiode.

Abstract: An electron-emitting device having an electroconductive film including an electron-emitting region arranged between a pair of device electrodes is manufactured. The electroconductive film is formed by applying a liquid containing the material of the film to a substrate by using an ink-jet method, then drying and heating the applied liquid. Defective conditions, if any, in the applied liquid or the precursor film formed by drying the liquid or the electroconductive film formed by heating the precursor film are detected and remedied by applying the same liquid again to the area detected for a defective condition. The detection and remedy of any defective condition may be conducted after the liquid-applying, drying or baking step.

Abstract: The invention provides a method of manufacturing a large-area electronic device, for example a flat panel display, comprising thin-film circuit elements, and also laser apparatus for crystallizing a portion of a semiconductor thin-film (1) with a beam (11) of set energy. The energy of the beam (11) is set in accordance with the output from a light detector (22) to regulate the crystallization of a device portion (3,4 and/or 5) of a semiconductor thin film (1) at which the beam (11) is subsequently directed with its set energy. The light detector (22) monitors the surface quality of a previously crystallized portion (2). In accordance with the present invention, the light detector (22) is located at a position outside the specular reflection path (25) of the light returned by the surface area of the crystallized portion (2) and detects a threshold increase (D) in intensity (I.sub.s) of the light (26) being scattered by the surface area of the crystallized portion.

Abstract: A sensor and a method for determining the basis weight of a coating material containing CaCO.sub.3 on a substrate is described. The determined basis weight is insensitive to changes in the amount of substrate material underlying the coating. Signals from the sensor may be used in the control of a coating mechanism to provide a coating having a uniform basis weight.

Abstract: The change in thickness of a film on an underlying body such as a semiconductor substrate is monitored in situ by inducing a current in the film, and as the thickness of the film changes (either increase or decrease), the changes in the current are detected. With a conductive film, eddy currents are induced in the film by a generating an alternating electromagnetic field with a sensor which includes a capacitor and an inductor.

Abstract: A method of producing an electron-emitting device includes the steps of forming a pair of electrodes and an electrically-conductive thin film on a substrate in such a manner that the pair of electrodes are in contact with the electrically-conductive thin film and forming an electron emission region using the electrically-conductive thin film, wherein a solution containing a metal element is supplied in a droplet form, such as by an inkjet system, onto the substrate thereby forming the electrically-conductive thin film.

Abstract: In an annealing process in which laser light is irradiated to a semiconductor thin film, a refractive index of the semiconductor thin film after laser light irradiation is measured and conditions for the next laser light irradiation are adjusted based on the measured refractive index value. For example, laser light irradiation conditions are adjusted so that semiconductor thin films always have the same refractive index. As a result, the annealing can be performed under the same conditions at every laser light irradiation even if the laser light irradiation conditions vary unavoidably. For a crystalline silicon film, if the refractive index is larger than 3.5, then a thin-film transistor using such as film has desired crystallinity and flatness properties such that a field-effect mobility is greater than 100 cm.sup.2 /Vsec.

Abstract: A method and apparatus for monitoring a parameter of the RF power applied to a plasma-enhanced chemical vapor deposition (PECVD) chamber. The parameter is used to monitor an aspect of the chamber or a process in the chamber. In particular, the parameter can be used to determine whether the susceptor is properly aligned, determine the spacing of the susceptor from the gas discharge head, determine whether the wafer is properly aligned on the susceptor, determine whether there has been any deterioration of the susceptor or the gas discharge head, and determine whether a chamber clean operation is complete.

Abstract: A method for coating an optical fiber (1) has the optical fiber (1) exiting the longitudinal direction through a coating nozzle (10) from a volume (11) which is filled with a liquid hardenable coating material (6). The surface of the fiber is spaced from the wall (12) of the coating nozzle (10). The viscosity of the coating material (6) at room temperature is greater than 2500 mPa.multidot.s and the temperature of the coating material (6) is adjusted high enough for the coating material (6) to have a viscosity of less than 2000 mPa.multidot.s.

Abstract: A screen printing method is provided in which the exchange of machine types is achieved in a short time and even minute patterns or narrowly pitched patterns can be precisely positioned for screen printing. The method comprises finding an amount of movement of the circuit board from positions of recognition marks (2, 2) on a circuit board (1) and positions of recognition marks (5, 5) on a screen plate (4), positioning the circuit board (1) in relation to the screen plate (4) on the basis of the amount of movement of the circuit board (1), detecting a discrepancy between a pattern of apertures (18) and a pattern of lands (19) in a particular portion of the circuit board (1), finding a positional correction from the discrepancy, and positioning the circuit board (1) in relation to the screen plate (4) on the basis of the amount of movement of the circuit board and the positional correction.

Abstract: Apparatus for determining a best trajectory for laser CVD through a strategy of acquiring a series of two-dimensional plane images of the substrate. These images, taken together, contain topographical information as well as local reflectivity and thermal mapping information. The images are combined in digital format with additional substrate mapping information to calculate a best three-dimensional trajectory for the desired laser operation. The technique is especially suitable for compensation of tilt or severe height variation on microelectronic parts. The apparatus can deposit platinum conductors on integrated circuits by pyrolytic deposition from Pt(PF.sub.3).sub.4 vapor.

Abstract: Methods and apparatus for detecting imperfections in adhesive coatings formed on fingers of beams are disclosed. The present invention relates, in one aspect, to a method for preparing a first work piece for joining with a second work piece. The method involves forming a finger in the first work piece, then applying an adhesive coating on the finger. A determination is made to determine whether the adhesive coating is defective through the used of a sensing mechanism which is arranged to scan across a portion of the finger. In one embodiment, a defect in the adhesive coating on the finger is defined as a void.

Abstract: An apparatus and procedure for applying a protective coating to a lens disc; the procedure comprises the positioning of trays (7) carrying lens discs, on a conveyor belt (9), which comes to a halt opposite a sensor means which detects the lenses; the tray (7) enters a coating chamber (4) provided with a coating diffusor (11); and the tray (7) comes to a halt repeatedly leaving one of the lens carried on the tray (7) opposite the diffusor (11); the pulverised coating material is sprayed onto the lens and then the tray (7) passes on to a drying section (3). The apparatus comprises trays (7) carrying lenses; a means for the transport thereof; a chamber (4), provided with a coating diffusor (11) and a gas extraction means (13); there is also a sensor means (15) and a stopping means for regulating the movement of the tray (7) as far as the drying section (3).

Abstract: A wafer coating apparatus for use in the application of a viscous precursor fluid on a substrate surface of a silicon substrate. The coating apparatus includes a carrier mechanism adapted to support the substrate thereon; and a coating head having a deposition surface positioned proximate and substantially parallel to the substrate surface. The deposition surface defines at least one orifice in flow communication with the precursor fluid for deposition thereof between the substrate surface and the deposition surface. The coating apparatus further includes a rotating device coupled to at least one of the coating head and the carrier mechanism for relative rotational movement between the deposition surface and the substrate surface about a rotational axis to form a thin circular film coating on the substrate surface. A method of coating a silicon substrate surface of a substrate is also provided.

Abstract: A technique for creating a patterned coating entails forming a first region (26) over a primary component (22). A second region (28) is formed over part of the first region. The first region is etched so as to undercut the second region, thereby forming a gap (30) below part of the second region. Coating material is then provided over the structure. Due to the presence of the gap, the coating material accumulates over the structure in a pair of segments spaced apart along the gap. One coating segment (32A) overlies the primary component. The other coating segment (32B) overlies the second region.

Abstract: An apparatus for applying a coating to the head-shank junction of externally threaded fasteners in an automated fashion. The fasteners are positioned, head down, on rotating part holders positioned about the periphery of a rotating disc. The part holders may be magnetic or other forms, and are adapted to maintain the fasteners in a generally fixed position during their movement. The fasteners are pre-heated at a heating station during their rotational movement on the disc. A dispenser is then used to apply the coating to the articles, in timed sequence to the movement of the articles. In this fashion, a coating can be applied to selected portions of the entire periphery of the head-shank junction. A method for applying a coating to the head-shank junction of externally threaded fasteners in an automated fashion also forms part of the present invention.

Abstract: The present invention is directed to providing thin-film-coated substrate manufacturing methods and apparatus that make it possible to manufacture large thin-film-coated substrates such as anti-reflection filters using relatively small production facilities. The thin-film-coated substrate manufacturing methods pertaining to the present invention area capable of producing thin films on substrates to be coated as large as the film formation area by using a film formation monitor or monitors placed outside of the film formation area or displaceably mobile therein, measuring the thickness of the monitor thin film or films formed on the film formation monitor or monitors, and controlling the film coating process based on the measured thickness of the monitor thin film or films. It is also capable of increasing the productivity of the manufacturing process through increased flexibility in the arrangement of substrate or substrates to be coated inside the film formation area.

Abstract: The invention relates to a method and apparatus for optimizing the transfer efficiency of a compressed air system used to apply liquid coatings (e.g., paint) while producing a high quality film coating. The invention uses a laser measuring system to determine the atomization of a spray produced by a compressed air spray system. The system also monitors and measures the liquid and air being supplied to the spray applicator to determine the settings required for optimization.

Abstract: The reduction of surface recombination is required for the manufacture of electronic devices made of silicon as well as for the application of various measurements and analytical methods for determining the purity of silicon. According to this invention, a process will be described for applying a laquer layer to the surface of silicon wafers, wherby the surface recombination velocity will be reduced to a value below 100 cm/s.

Abstract: A film deposition control system and method in which a deposition rate monitor and an ellipsometer are used to control the thickness of a thin film being deposited on a wafer. The ellipsometer is also used to detect the refractive index of the thin film being deposited, and the detected refractive index value is used to control the ratio of the reactive gases being injected into the processing chamber.

Abstract: This invention pertains to fluorophoric compositions of a 7-amino-coumarin derivative and methods of their use for enhancing visualization of various constituents of ion selective electrodes.

Abstract: A coating film forming method for forming a resist coating film on an upper surface of a wafer held by a spin chuck in a chamber includes (a) the step of keeping preliminary correlation data representing correlation between a wafer rotating speed and the thickness of the resist coating film formed on the wafer in the chamber, (b) the step of conveying the wafer into the chamber and holding the wafer by the spin chuck, (c) the step of pouring the resist liquid onto the wafer and spin-rotating the wafer to form a resist coating film on the upper surface of the wafer, (d) the step of detecting the thickness of the formed resist coating film by a sensor, (e) the step of detecting a rotating speed of the spin chuck by a sensor, and (f) the step of, on the basis of the detected film thickness and the preliminary correlation data, correcting a set rotating speed of the spin chuck to feedback-control a resist coating process for a next wafer.

Abstract: The present invention relates to methods and apparatus for the controlled placement of a shear-thinnable polymer composition into a moving web. The controlled placement is preferably performed by applying the polymer composition onto a surface of a moving web, shear thinning the composition and placing it into the web, and curing the polymer composition. A preferred apparatus includes one or more process heads that has mounted thereto a rigid knife blade for engagement with the moving web. The knife blade is movable vertically and rotationally. The process head is also movable horizontally along the path of the moving web. A plurality of macro and micro tension zones are established and are monitored for controlling the apparatus and process.

Abstract: A method for fabricating a gradient index optical filter comprising a thin film having a low refractive index contrast and a specific reflectance function structured using the phase of the refractive index profile as a variable to permit closed form, constrained optimization of rugate filters.

Abstract: In a PECVD process, the plasma potential is controlled and maintained at a uniform level to confine the formed plasma to the gap area between the electrodes away from the influence of the walls of the discharge chamber. The plasma potential is controlled by operating the system at a high pressure, above about 12 Torr, and monitoring the operation by observing the DC bias on the upper or driven electrode until a positive potential, preferably greater than about 10V, is developed. At this point a symmetrical glow discharge and a controlled plasma exists between the driven electrode and the susceptor electrode, controllable by maintaining the pressure between about 14 and 20 Torr, to reduce plasma damage to the semiconductor body being coated which maximizes yield.

Abstract: Continuous vapor deposition apparatus for coating objects with a coating material, e.g., parylene, are disclosed. The apparatus comprise an entrance chamber for loading the objects, a process chamber for coating the objects, and an exit chamber for removing the objects. Coating material is introduced into the process chamber under vacuum conditions in a vaporized state. The pressure in the process chamber can be controlled by modulating the rate of introduction of the coating material with a modulating valve in response to the pressure in the process chamber. A process for continuously coating objects by vapor deposition under vacuum conditions, suitable for use in the apparatus, is also disclosed.

Abstract: A substrate such as a semiconductor wafer is transferred to a plurality of process chambers so as to perform prescribed processes. An inspection chamber is air-tightly connected to each of the process chambers. The inspection chamber is provided with a handler which loads and unloads the substrate. A gate valve is disposed between each process chamber and the inspection chamber. By this gate valve, each chamber is air-tightly closed.