JP6238438B2 - Substrate floating device - Google Patents

Description

  The present invention relates to a substrate levitating apparatus that levitates a substrate by ultrasonic vibration.

  A flat panel display such as a liquid crystal display or a plasma display uses a substrate coated with a resist solution (referred to as a coated substrate). The coated substrate is produced by forming a coating film by uniformly applying a resist solution on the substrate by a coating apparatus, and then drying the coating film by a heat treatment apparatus.

  As one type of this heat treatment apparatus, for example, there is a levitation conveyance heat treatment apparatus as shown in Patent Document 1 and FIG. As shown in FIG. 3, a plurality of substrate levitation devices 91 each including a vibration plate portion 92 and an ultrasonic wave generation portion 93 are arranged in the levitation transfer heat treatment device 90, and each substrate levitation device 91 ultrasonically converts the substrate W into ultrasonic waves. Vibrate to vibration. In addition, the diaphragm unit 92 is heated to a predetermined temperature by the heating device 94 in some or all of the substrate levitation apparatuses 91, and the substrate levitation apparatus 91 causes the substrate W to ultrasonically levitate and float in this state. Heat to a predetermined temperature without contact. Then, by transporting the substrate W in order from the substrate levitation device 91 to the next substrate levitation device 91 by a transport device (not shown), the levitation transport heat treatment device 90 can dry and bake the coating film on the substrate W with a predetermined temperature history. Can be done.

JP 2012-248755 A

  However, the levitation transfer heat treatment apparatus 90 having the above-described substrate levitation apparatus 91 has a problem that the diaphragm 92 and the ultrasonic generator 93 may interfere with each other and generate noise. Specifically, if the connection position between the diaphragm 92 and the ultrasonic generator 93 is at or near the resonance node of the diaphragm 92 as shown in FIG. 4A, the diaphragm due to vibration at that position. The deformation of the portion 92 is small and interference between the vibration plate portion 92 and the ultrasonic wave generation portion 93 is unlikely to occur, but the connection position between the vibration plate portion 92 and the ultrasonic wave generation portion 93 is as shown in FIG. If it is at or near the antinode of resonance of the diaphragm 92, the deformation of the diaphragm 92 due to the vibration at that position is large, and the diaphragm 92 and the ultrasonic generator 93 interfere with each other, and noise is generated at that time. There was a problem to do.

  In addition, such a problem particularly occurs even when the resonance frequency of the object to be vibrated (the vibration plate portion 92 in this case) changes by the ultrasonic wave generation unit 93, and automatically tracks the resonance frequency so that the target is always efficiently performed. This is likely to occur when an automatic tracking function for vibrating an object is provided. This is because the resonance frequency of the diaphragm 92 changes depending on the temperature of the diaphragm 92, and the resonance nodes and antinode positions of the diaphragm 92 change depending on the vibration frequency of the diaphragm 92. When an unexpected temperature change occurs in the diaphragm 92 for some reason, the ultrasonic wave generator 93 changes the frequency of its own vibration to the resonance frequency of the diaphragm 92 at that time. This is because the connection position between 92 and the ultrasonic wave generation section 93 can be the position of the antinode of resonance of the diaphragm section 92. In this case, when each substrate levitation apparatus 91 floats and dries the normal substrate W, an unexpected temperature change occurs in the diaphragm 92 even though there is no interference between the diaphragm 92 and the ultrasonic generator 93. When this occurs, the diaphragm 92 and the ultrasonic generator 93 interfere with each other, which may generate noise.

  In particular, when the noise is a sound having an audible frequency, if the noise continues to be emitted for a long time, there is a risk of harming the hearing of the worker working near the levitation conveyance heat treatment apparatus 90. It is necessary to mitigate the noise.

  The present invention has been made in view of the above-described problems, and an object thereof is to quickly detect noise generated from a diaphragm.

  In order to solve the above problems, a substrate levitation apparatus according to the present invention includes a vibration plate portion on which a substrate is placed, and an ultrasonic wave generation portion that is connected to the vibration plate portion and applies ultrasonic vibration to the vibration plate portion. And a levitation unit that ultrasonically levitates the substrate on the diaphragm part, and a sound sensor part that is provided in a traveling direction of sound emitted from the diaphragm part and detects sound in an audible range. It is characterized by.

  According to the above-described substrate floating device, the substrate floating device itself can quickly detect the noise when an audible noise that may cause harm to the worker is generated from the diaphragm. In addition, using noise detection as a trigger, control is performed to quickly mitigate noise by automatically stopping the operation of the levitating unit that caused noise or changing the frequency of vibration automatically. You can also.

  In order to solve the above problems, another substrate levitation apparatus according to the present invention includes a vibration plate portion on which a substrate is placed, and an ultrasonic wave generator that is connected to the vibration plate portion and applies ultrasonic vibration to the vibration plate portion. A levitation unit that ultrasonically levitates the substrate on the diaphragm part, a sound sensor part provided in a traveling direction of sound emitted from the diaphragm part, and the sound sensor part And an analysis unit that analyzes the frequency of the sound and determines the presence or absence of a sound having a frequency other than the ultrasonic vibration frequency of the diaphragm.

  According to the above-described substrate levitation apparatus, when audible noise that may cause harm to the worker is generated from the diaphragm, the presence of sound having a frequency other than the ultrasonic vibration frequency of the diaphragm portion is determined by frequency analysis. By detecting, the substrate floating apparatus itself can quickly detect noise. In addition, using noise detection as a trigger, control is performed to quickly mitigate noise by automatically stopping the operation of the levitating unit that caused noise or changing the frequency of vibration automatically. You can also.

  A plurality of the levitation units are arranged, and a plurality of the sound sensor units are arranged so that one levitation unit corresponds to one sound sensor unit, and a partition wall is provided between the adjacent sound sensor units. Should be provided.

  By doing so, the sound sensor unit can reliably detect the sound emitted from the diaphragm of the corresponding floating unit without being confused by the sound emitted from the diaphragm of the other floating unit. If it occurs, it is possible to reliably identify which floating unit it is from.

  According to the substrate floating device of the present invention, it is possible to quickly detect noise generated from the diaphragm.

It is the schematic of the board | substrate floating apparatus in one Embodiment of this invention. It is the schematic of the substrate floating apparatus in other embodiment of this invention. It is the schematic of the conventional board | substrate floating apparatus. It is the schematic which shows the relationship between the vibration state of a diaphragm part, and noise generation.

  Embodiments according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view of a substrate floating apparatus according to an embodiment of the present invention. The substrate levitation apparatus 1 includes a levitation unit 2, a sound sensor unit 3, and a control unit 4. While the levitation unit 2 levitates the substrate W in a non-contact manner, a transfer device (not shown) transfers the substrate W to the adjacent levitation unit 2. Are sequentially transferred to the coating film on the substrate W. Further, when noise is generated from the levitation unit 2, the sound sensor unit 3 detects the noise, and the control unit 4 reflects the detection result to stop the levitation unit 2, and automatically controls the noise. To calm down quickly.

  The levitation unit 2 includes a vibration plate unit 11 and an ultrasonic wave generation unit 12, and the vibration plate unit 11 that is ultrasonically vibrated by the ultrasonic wave generation unit 12 causes the substrate W to be ultrasonically vibrated and floated.

  Some of the levitation units 2 further include a heater unit 14, and the heater unit 14 heats the diaphragm unit 11 to a predetermined temperature, so that the diaphragm unit 11 reaches the predetermined temperature while the substrate W is levitated. Can be heated.

  The diaphragm 11 is a metal plate having a rectangular plate shape and has a flat surface. In this embodiment, the diaphragm 11 is formed by continuously arranging rectangular plates made of aluminum (made of aluminum alloy) in the substrate transport direction (Y-axis direction).

  The diaphragm 11 is connected to an ultrasonic generator 3 described later, and vibrates at the same frequency as the vibration of the ultrasonic generator 3 when the ultrasonic generator 3 oscillates. In particular, when the diaphragm 11 vibrates at a frequency corresponding to the resonance frequency, the vibration of the diaphragm 11 increases. Therefore, the ultrasonic wave generator 3 oscillates at a frequency corresponding to the resonance frequency of the diaphragm 11 when the diaphragm 11 is vibrated to lift the substrate W.

  Moreover, the diaphragm part 11 can heat the board | substrate W levitated on the diaphragm part 11 by radiation heating by being heated by the heater part 14 as above-mentioned.

  Here, the dimension in the X-axis direction and the dimension in the Y-axis direction of the diaphragm 11 are larger than the dimensions in the X-axis and Y-axis directions of the substrate W when the substrate W is placed on the diaphragm 11. Is set. As a result, when the substrate W is heated while floating on the vibration plate portion 11, the entire surface of the substrate W exists on the vibration plate portion 11 without the portion where the substrate W protrudes from the vibration plate portion 11. Therefore, the substrate W can be uniformly heated by the diaphragm portion 11 heated by the heater portion 14.

  The diaphragm 11 is placed on an elastic spacer 13 such as a rubber sheet, and the spacer 13 is fixed to a frame of the main body of the substrate floating apparatus 1. The reason why the spacer 13, not the diaphragm 11, is fixed to the base of the main body of the substrate levitation apparatus 1 is that the diaphragm 11 is ultrasonically vibrated by the ultrasonic generator 12 as described above. If the part 11 is directly connected to the gantry of the main body of the substrate levitation apparatus 1, the entire substrate levitation apparatus 1 may vibrate, and the vibration of the diaphragm 11 may be adversely affected. On the other hand, since the spacer 13 vibrates the vibration plate portion 11 due to its elasticity, it is possible to prevent the vibration of the vibration plate portion 11 from being transmitted to the gantry of the main body of the substrate floating apparatus 1.

  The ultrasonic generator 3 has an ultrasonic transducer and a horn. The ultrasonic transducer is disposed on the side opposite to the surface on which the substrate W is levitated with respect to the diaphragm 11 when viewed from the Z-axis direction. A horn is connected to the ultrasonic vibrator, and this horn is in contact with and connected to the diaphragm portion 11.

  The ultrasonic vibrator excites a target object based on an oscillation signal from an oscillator (not shown). For example, there is a Langevin type vibrator having an electrode and a piezoelectric element. In the Langevin type vibrator, when a driving voltage is applied to an electrode by an oscillator, the piezoelectric element vibrates and oscillates with a predetermined amplitude and frequency. The vibration of the ultrasonic vibrator oscillated in this way propagates to the diaphragm 11 that is the object via the horn. Thereby, the diaphragm 11 vibrates at the same frequency as the vibration of the ultrasonic vibrator. When the diaphragm 11 vibrates, a radiated sound pressure is generated from the diaphragm 11, and an upward force is applied to the substrate W on the diaphragm 11 by the radiated sound pressure. As a result, the substrate W can be held in a state where it floats above the diaphragm 11 by a predetermined flying height.

  Further, the vibration of the ultrasonic vibrator can be adjusted in amplitude and frequency by controlling the drive voltage applied from the oscillator, and thereby the flying height of the substrate W that floats on the diaphragm 11 is adjusted. Is possible. In the present embodiment, the frequency of the ultrasonic vibrator, that is, the vibration frequency of the diaphragm 11 is 20 kHz or more, and the flying height of the substrate W is about 0.1 mm.

  The horn has a shape in which a cylinder or a plurality of cylinders are connected, one end is connected to the ultrasonic vibrator, and the other end is connected to the diaphragm 11, and the amplitude of vibration generated by the ultrasonic vibrator is determined. Amplified or attenuated and propagates to the diaphragm 11. Further, since the horn is arranged to penetrate the spacer 13 and the heater portion 14, the spacer 13 and the heater portion 14 are provided with through holes or notches at positions where the horn is arranged to avoid interference with the horn. .

  Further, the ultrasonic generator 12 automatically tracks the resonance frequency even when the resonance frequency of the object to be vibrated (here, the vibration plate part 11) changes due to a temperature change or the like, and vibrates the object efficiently. It has an auto-tracking function. Specifically, the ultrasonic generator 12 changes the vibration frequency little by little at predetermined time intervals, and measures the oscillation output necessary for the ultrasonic generator 12 to vibrate the vibrating object. By continuing this operation, the ultrasonic generator 12 has a function of constantly obtaining a condition for reducing the oscillation output.

  The heater unit 14 includes a plurality of heater units in the present embodiment, and these heater units are arranged in the X-axis direction and the Y-axis direction. In the present embodiment, the heater unit is a plate heater configured by inserting a cartridge heater or a sheathed heater into a rectangular aluminum plate.

  Moreover, the heater part 14 is located on the opposite side of the diaphragm part 11 with the spacer 13 interposed therebetween, and is in contact with the spacer 13 without a gap, and directly heats the spacer 13 without passing air. Thereby, compared with the case where a space is provided between the heater part 14 and the diaphragm part 11 and heat transfer to the diaphragm part 11 is performed by radiation or convection, the efficiency of heat conduction can be improved. Yes.

  In this embodiment, the sound sensor unit 3 is a condenser microphone, and a plurality of sound sensor units 3 are installed above each floating unit 2 so that one sound sensor unit 3 corresponds to one floating unit 2. Has been. In addition, the upper part of the levitation unit 2 is the traveling direction of the sound emitted from the diaphragm unit 11 included in the levitation unit 2, and the sound sensor unit 3 can acquire the sound emitted from the diaphragm unit 11.

  When the sound sensor unit 3 detects noise that cannot be left in the sound acquired by the sound sensor unit 3, the sound sensor unit 3 outputs a signal to the control unit 4 described later.

  Here, as described above, each diaphragm unit 11 emits a sound wave in an ultrasonic region of 20 kHz or more to float the substrate W, and therefore the sound frequency that can be acquired by the sound sensor unit 3 so as not to detect this sound wave. This range is an audible range lower than the ultrasonic range. In the present embodiment, the sound sensor unit 3 employs a capacitor microphone having a frequency characteristic with a detectable frequency of 50 Hz to 16 kHz. As a result, it is possible to detect even the ultrasonic waves generated when the floating unit 2 normally lifts the substrate W and prevent it from being erroneously recognized as an abnormality of the apparatus, and to detect noise accurately. .

  Further, in order to prevent the sound sensor unit 3 from detecting a noise generated in the vicinity of the substrate levitation apparatus 1 and the like so that the control unit 4 erroneously performs control such as stopping the operation of the levitation unit 2. Outputs a signal to the control unit 4 only when it detects only a sound with a sound volume of a predetermined level or higher, for example, a sound with a sound volume of a level higher than the level that the operator recognizes as noise (for example, 100 dB).

  In addition, a partition wall 21 is provided between adjacent sound sensor units 3, and sound emitted from the levitation unit 2 is transmitted to the sound sensor unit 3 corresponding to the levitation unit 2 (directly above the levitation unit 2). It reaches only the sound sensor unit 3) that is located, and the other sound sensor units 3 do not acquire the sound.

  It is desirable that the partition wall 21 has a high sound absorption characteristic so that sound does not reach other sound sensor units 3. However, since the partition wall 21 is located above the substrate W, low dust generation and solvent resistance (not to be corroded by the solvent volatilized from the coating film) are also important. In this embodiment, a metal plate such as stainless steel is used. Used as a material for the partition wall 21.

  In addition, if the sound sensor unit 3 acquires sound emitted from only one floating unit 2 as described above, it is desirable that the sound sensor unit 3 has unidirectionality. And only the sound emitted from the corresponding levitation unit 2 can be efficiently acquired by clearly capturing only the sound from the direction in which the levitation unit 2 is located (downward as viewed from the sound sensor unit 3). .

  Here, in the present embodiment, as described above, a microphone having a frequency characteristic that allows only the audible range to be acquired is employed as the sound sensor unit 3. However, as another embodiment, the sound sensor unit 3 includes only the sound in the audible range. In addition, it has a frequency characteristic that can also acquire ultrasonic waves generated when the substrate W vibrates and floats, and the signal is sent to the control unit only when it is determined that the sound acquired by the sound sensor unit 3 is frequency-analyzed and mixed with abnormal noise. May be output.

  Specifically, the substrate levitation apparatus 1 further includes an analysis unit that performs frequency analysis by Fourier-transforming the sound acquired by each sound sensor unit 3, and what frequency is the combination of the acquired sounds Is analyzed. Then, the presence or absence of sound having a frequency other than the ultrasonic vibration frequency (for example, 40 kHz) of the diaphragm 11 is determined, and if it is determined that sound having a frequency other than the ultrasonic vibration frequency is also mixed, a signal is transmitted. You may make it output to the control part 4. FIG. Even in such an embodiment, even ultrasonic waves generated when the levitation unit 2 normally floats the substrate W are detected to prevent erroneous recognition as an abnormality of the apparatus, and noise is accurately detected. It is possible.

  In the present embodiment, the control unit 4 includes a computer, a sequencer, and the like, and is electrically connected to each floating unit 2. On / off of vibration of each floating unit 2, vibration frequency, holding time of the substrate W (mounting) For example, the operation time of the transfer device (not shown). The control unit 4 has a storage device that stores various information, such as a hard disk and a memory such as a RAM or a ROM, and the control data is stored in the storage device.

  The control unit 4 is also electrically connected to each sound sensor unit 3, and a signal output from the sound sensor 3 when the sound sensor unit 3 detects an abnormal sound is input to the control unit 4. Here, each sound sensor unit 3 is independently connected to the control unit 4, and the control unit 4 determines whether the signal is output from the sound sensor unit 3 when a signal is input. be able to. And based on this input signal, the control part 4 is controlled to switch the operation | movement of the levitation unit 2 corresponding to the sound sensor 3 which output the signal.

  Moreover, when the board | substrate floating apparatus 1 has the above-mentioned analysis part, this control part 4 may have a function of an analysis part.

  Next, the mechanism by which the substrate levitating device 1 detects noise will be described with reference to FIG.

  In the example of FIG. 1, the substrate levitation apparatus 1 has six levitation units 2, and a sound sensor unit 3 is provided above each levitation unit 2.

  In such a substrate levitation apparatus 1, it is assumed that noise is generated in the diaphragm 11a of the third levitation unit 2a from the right in FIG. As described above, the cause of the noise is that the resonance frequency of the diaphragm 11a is changed by the temperature change of the diaphragm 11a, etc., and the ultrasonic generator 12a tracks this to change the vibration frequency. In this case, there may be a case where the connecting position of the vibration plate portion 11a and the ultrasonic wave generation portion 12a hits the resonance antinode position of the vibration plate portion 11a or the vicinity thereof.

  At this time, the noise emitted from the diaphragm portion 11 a reaches only the sound sensor portion 3 a directly above the diaphragm portion 11 a by the partition wall 21, and does not reach the other sound sensor portions 3. When the sound sensor unit 3 a detects this noise, the sound sensor unit 3 a outputs a signal to the control unit 4.

  Next, when a signal is input to the control unit 4 only from the sound sensor unit 3a, the control unit 4 easily determines that noise is emitted from the corresponding levitation unit 2a, and the levitation unit Control to switch the operation of 2a is performed. Specifically, the frequency of ultrasonic vibration of the diaphragm 11a is changed or the operation of the levitation unit 2a is stopped.

  In this way, the control unit 4 can identify the floating unit 2a that generates noise, so that only the problematic floating unit 2a changes the frequency of vibration, and no noise is generated without stopping the substrate floating device 1 even once. The substrate W can be lifted again below, and the automatic operation can be continued.

  Even when control is performed so that the operation of the levitation unit 2 is stopped when noise is generated, only the levitation unit 2a that caused the noise is stopped, and the levitation unit 2 that is downstream of the levitation unit 2a is levitated. Since the substrate W (the substrate W1 in FIG. 1) that is being processed can be continuously processed, the number of substrates W to be discarded can be reduced.

  With the above substrate floating device, it is possible to quickly detect noise generated from the diaphragm.

  In the above description, one sound sensor unit 3 is associated with one levitation unit 2, but one sound sensor unit 3 is associated with two or more levitation units 2 as shown in FIG. You may make it correspond. As a result, the number of the sound sensor units 3 can be reduced to reduce the device cost, and in particular, as shown by f = f1, f = f2, and f = f3 in FIG. When the frequencies of the abnormal sounds are different from each other, it is possible to determine from which floating unit 2 the abnormal noise is generated by the analysis unit analyzing the frequency of the abnormal sounds.

  Moreover, in the above description, when the sound sensor unit 3 detects an abnormal sound, the control unit 4 automatically performs control such as operation stop of the levitation unit 2, but this is not necessarily the case. The control unit 4 may sound an alarm to warn workers around the substrate floating apparatus 1. In this case, an operator who notices the alarm manually controls the substrate floating apparatus 1 and performs appropriate measures.

DESCRIPTION OF SYMBOLS 1 Substrate levitation device 2 Levitation unit 3 Sound sensor part 4 Control part 11 Vibration plate part 12 Ultrasonic wave generation part 13 Spacer 14 Heater part 21 Partition 90 Levitation conveyance heat treatment apparatus 91 Substrate levitation apparatus 92 Vibration plate part 93 Ultrasonic wave generation part 94 Heating Equipment W Substrate

Claims (2)

A vibration plate portion on which the substrate is placed; and an ultrasonic wave generation portion that is connected to the vibration plate portion and applies ultrasonic vibration to the vibration plate portion. A floating unit
A sound sensor unit that is provided in a traveling direction of sound emitted from the diaphragm unit and detects sound in an audible range;
Equipped with a,
A plurality of the levitation units are arranged, and a plurality of the sound sensor parts are arranged so that one levitation unit corresponds to one sound sensor part, and a partition is provided between the adjacent sound sensor parts. A substrate levitation apparatus characterized in that: A vibration plate portion on which the substrate is placed; and an ultrasonic wave generation portion that is connected to the vibration plate portion and applies ultrasonic vibration to the vibration plate portion. A floating unit
A sound sensor unit provided in a traveling direction of sound emitted from the diaphragm unit;
Analyzing the frequency of the sound acquired by the sound sensor unit, and determining the presence or absence of a sound having a frequency other than the frequency of the ultrasonic vibration of the diaphragm unit;
Equipped with a,
A plurality of the levitation units are arranged, and a plurality of the sound sensor parts are arranged so that one levitation unit corresponds to one sound sensor part, and a partition is provided between the adjacent sound sensor parts. A substrate levitation apparatus characterized in that:

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