JP2013077596A - Substrate processing method and substrate processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate processing method and a substrate processing apparatus which reduce the adhesive force of foreign objects to a substrate thereby reducing the running cost.SOLUTION: Droplets from a liquid drop nozzle 15 are supplied only to a part of a region on an upper surface of a substrate W. Then, the droplets held on the upper surface of the substrate W are cooled or heated. The cooling or heating of the droplets changes the temperature of the droplets on the substrate W. Particles contacting with the droplets are cooled or heated by the droplets to shrink or expand.

Description

  The present invention relates to a substrate processing method and a substrate processing apparatus for processing a substrate. Examples of substrates to be processed include semiconductor wafers, liquid crystal display substrates, plasma display substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, and photomasks. Substrate, ceramic substrate, solar cell substrate and the like.

In the manufacturing process of a semiconductor device or a liquid crystal display device, a substrate processing apparatus for processing a substrate such as a semiconductor wafer or a glass substrate for a liquid crystal display device is used.
A single-wafer type substrate processing apparatus described in Patent Document 1 includes a spin chuck that horizontally holds and rotates a substrate, a processing liquid nozzle that discharges a processing liquid toward the upper surface of the substrate held by the spin chuck, and And a cooling gas discharge nozzle for discharging a cooling gas toward the upper surface of the substrate held by the spin chuck.

  In this substrate processing apparatus, a processing liquid is discharged from the processing liquid nozzle, thereby forming a liquid film covering the entire upper surface of the substrate. Thereafter, the cooling liquid is discharged from the cooling gas discharge nozzle, so that the entire liquid film is frozen together with the particles on the substrate. As a result, a frozen film containing particles is formed on the substrate. The frozen film is thawed by supplying the processing liquid to the substrate, and then discharged to the periphery of the substrate by centrifugal force due to the rotation of the substrate. Particles on the substrate are removed from the substrate together with the frozen film.

JP 2008-71875 A JP 2008-016660 A

  The region where particles are present on the upper surface of the substrate is not the entire upper surface of the substrate but a partial region within the upper surface of the substrate. However, in the substrate processing apparatus described in Patent Document 1, the processing liquid is supplied to the entire upper surface of the substrate, and a liquid film covering the entire upper surface of the substrate is formed. That is, since an excessive process liquid is supplied to the substrate, the process liquid is wasted. Furthermore, since a large liquid film is formed covering the entire upper surface of the substrate, the consumption of the cooling gas used when freezing the liquid film is large. As described above, in the conventional substrate processing apparatus, a large amount of processing liquid or the like is used, so that the running cost increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a substrate processing method and a substrate processing apparatus that can reduce the adhesion of foreign matter to a substrate and can reduce running costs.

In order to achieve the above object, the invention described in claim 1 includes a droplet supplying step of supplying droplets only to a partial region in the main surface of the substrate (W), and a temperature of the droplets on the substrate. And a temperature changing step for changing the temperature. The main surface of the substrate may be the surface of the substrate that is the device forming surface, or may be the back surface opposite to the front surface.
According to this method, droplets are supplied to only a part of the region in the main surface of the substrate. Thereafter, the droplets held on the main surface of the substrate are cooled or heated. As a result, the temperature of the droplet on the substrate changes. When the foreign matter on the substrate is in contact with the droplet, the foreign matter is cooled or heated by the droplet and contracts or expands. Therefore, a stress is generated between the substrate and the foreign material, and the adhesion force of the foreign material to the substrate is reduced. Thereby, it will be in the state in which a foreign material tends to peel from a board | substrate. Furthermore, since the liquid droplets are supplied only to a part of the main surface of the substrate, the amount of liquid consumption is smaller than when the liquid is supplied to the entire main surface of the substrate. In addition, since the amount of liquid on the substrate is small, it is possible to reduce substances that change the temperature of the droplets (for example, a coolant described later) and energy (for example, energy for generating infrared rays). Thereby, running cost can be reduced.

  The temperature changing step may be a step of cooling or heating the droplet on the substrate, or a step of cooling and heating the droplet on the substrate. That is, as in a second aspect of the invention, the temperature changing step may include a cooling step for cooling the droplets on the substrate and a heating step for heating the droplets on the substrate. . In this case, since the droplet on the substrate is cooled and heated, the amount of change in the droplet temperature is larger than when only cooling or heating is performed. Therefore, it is possible to increase the amount of displacement of the foreign matter that contacts the droplet. Thereby, the adhesive force of the foreign substance with respect to a board | substrate can be reduced reliably, and it can be in the state which a foreign substance tends to peel from a board | substrate.

  The cooling step may be a step of cooling the droplets on the substrate to a temperature lower than room temperature (20 to 30 ° C.). The heating step may be a step of heating the droplet on the substrate to a temperature higher than room temperature. For example, as in the invention described in claim 3, the cooling step may include a freezing step of freezing the droplets on the substrate, and the heating step thaws the droplets on the substrate. A thawing step may be included. That is, when the liquid supplied to the main surface of the substrate is a liquid containing water as a main component, the cooling step may be a step of cooling droplets on the substrate to 0 ° C. or less, and the heating step The step of heating the droplet on the substrate to a temperature higher than 0 ° C. may be used. In this case, since the amount of change in the droplet temperature can be increased, the amount of displacement of the foreign matter in contact with the droplet can be increased. Thereby, the adhesive force of the foreign substance with respect to a board | substrate can be reduced reliably, and it can be in the state which a foreign substance tends to peel from a board | substrate.

Further, the temperature changing step may be a step of heating after cooling the droplets on the substrate or, conversely, a step of cooling after heating the droplets on the substrate. Further, the number of times of cooling may be one time or a plurality of times. Similarly, the number of times of heating may be one time or a plurality of times.
In the case where the cooling and heating of the droplets are performed a plurality of times, as in the invention according to claim 4, the temperature changing step includes a repeating step of alternately cooling and heating the droplets a plurality of times. Also good. In this case, since the foreign matter in contact with the droplet repeats contraction and expansion alternately, the adhesion force of the foreign matter to the substrate can be reduced as compared with the case where cooling and heating are performed only once. Thereby, it can be in the state which a foreign material tends to peel from a board | substrate.

  In addition, when the cooling and heating of the droplet are performed a plurality of times, a droplet supplying step for supplying the droplet only to a partial region in the main surface of the substrate, as in the invention according to claim 5, and a substrate The freezing step for freezing the upper droplet and the evaporation step for evaporating the droplet on the substrate may be performed a plurality of times in this order. In this case, the droplet on the substrate is cooled and frozen. Thereafter, the frozen droplets are heated and evaporated. Thereby, the droplet is removed from the substrate. Therefore, the droplet is supplied again to the main surface of the substrate. Then, the droplets are frozen and evaporated again. Thus, since the freezing and evaporation of the droplet are repeated, when the liquid supplied to the main surface of the substrate is a liquid mainly composed of water, the temperature of the droplet on the substrate is 0 ° C. or less. To a temperature higher than room temperature (for example, 100 ° C. or more). Therefore, it is possible to increase the amount of displacement of the foreign matter in contact with the droplets and reliably reduce the adhesion force of the foreign matter to the substrate.

  The cooling step may be a step of cooling droplets on the substrate by cooling the substrate, and the heating step may be a step of heating droplets on the substrate by heating the substrate. . Further, the cooling step may be a step of cooling the droplets on the substrate almost without cooling the substrate, and the heating step heats the droplets on the substrate almost without heating the substrate. It may be a process.

  That is, as in the invention described in claim 6, the cooling step may include a selective cooling step for selectively cooling droplets on the substrate, and the heating step is performed on the substrate. A selective heating step of selectively heating the liquid droplets may be included. In this case, since the droplet on the substrate is selectively cooled and heated, only the temperature of the droplet and the portion in contact with the droplet (the contact portion between the droplet and the substrate or the foreign matter in contact with the droplet) is greatly increased. The temperature of the entire substrate hardly changes. Therefore, while the temperature of the foreign substance in contact with the droplet changes significantly, the temperature of the substrate hardly changes. For example, when the temperature of both the foreign matter and the substrate is significantly increased, both the foreign matter and the substrate are greatly expanded. Therefore, the relative displacement amount at the contact portion between the foreign matter and the substrate is expanded only for the foreign matter. Smaller than the case. Therefore, only the droplets on the substrate are selectively cooled and heated, thereby further reducing the adhesion of foreign matter to the substrate. Thereby, it will be in the state which a foreign material tends to peel from a board | substrate further.

  Moreover, the area | region in the main surface of the board | substrate to which a droplet is supplied in a droplet supply process may be set for every board | substrate. That is, as in a seventh aspect of the invention, the substrate processing method includes a contamination state measurement that identifies a contaminated portion on the main surface of the substrate where foreign matter is attached before the droplet supply step is performed. The method may further include a step, and the droplet supplying step may include a step of supplying a droplet only to the contaminated portion. In this case, since the droplet is supplied only to the contaminated portion where the foreign matter is attached, the droplet can be reliably brought into contact with the foreign matter. Therefore, the foreign matter can be reliably contracted or expanded by changing the temperature of the droplet. Thereby, the adhesive force of the foreign material with respect to a board | substrate can be reduced. Further, since the droplet is supplied only to the contaminated portion, when the droplet is formed by the corrosive liquid that corrodes the substrate, it is possible to suppress or prevent the occurrence of damage to the region other than the contaminated portion.

  Moreover, the area | region in the main surface of the board | substrate to which a droplet is supplied in a droplet supply process may be preset. That is, as in the invention described in claim 8, the droplet supplying step includes a specific portion supplying step of supplying droplets to a predetermined portion (specific portion) in the main surface of the substrate. Also good. Further, the specific portion may be a peripheral portion of the main surface of the substrate. That is, the peripheral portion of the main surface of the substrate comes into contact with a hand of a transport robot that transports the substrate or a substrate holding means such as a spin chuck. Therefore, the peripheral portion of the main surface of the substrate is more easily contaminated than other regions of the substrate. Therefore, the area where the droplets are supplied may be set to an area that is easily contaminated. In these cases, since the region where the droplets are supplied is determined in advance, it is not necessary to change the droplet supply position with respect to the main surface of the substrate for each substrate.

  The liquid supplied to the main surface of the substrate (liquid forming droplets) may be a liquid containing water, a liquid containing a corrosive component that corrodes the substrate, or other It may be a liquid. For example, as in the ninth aspect of the invention, the droplet supplying step may include a step of supplying a droplet of a corrosive liquid that corrodes the substrate to only a part of the main surface of the substrate. Good. In this case, since the surface layer of the substrate is corroded by the corrosive liquid, the adhesion of foreign matter to the substrate can be reduced, or the foreign matter can be peeled off (lifted off) from the substrate.

  In order to achieve the above object, the invention described in claim 10 includes a substrate holding means (8) for holding the substrate (W) and a part of the main surface of the substrate held by the substrate holding means. Including a droplet supply means (9) for supplying droplets only to the region of the substrate and a temperature changing means (10, 11) for changing the temperature of the droplet on the substrate held by the substrate holding means. It is a processing apparatus (1). According to this configuration, it is possible to achieve an effect similar to the effect described with respect to the invention of claim 1.

The invention according to claim 11 is characterized in that the temperature changing means includes a cooling means (10) for cooling the droplets on the substrate and a heating means (11) for heating the droplets on the substrate. Item 11. The substrate processing apparatus according to Item 10. According to this configuration, it is possible to achieve the same effect as the effect described with respect to the invention of claim 2.
The invention according to claim 12 is characterized in that the cooling means includes freezing means (10) for freezing droplets on the substrate, and the heating means is thawing means (11) for thawing the droplets on the substrate. The substrate processing apparatus according to claim 11, comprising: According to this configuration, it is possible to achieve the same effect as the effect described with respect to the invention of claim 3.

The invention according to claim 13 further includes control means (5) for causing the cooling means and the heating means to alternately cool and heat the droplets a plurality of times. Device. According to this configuration, it is possible to achieve the same effect as the effect described with respect to the invention of claim 4.
The invention according to claim 14 is characterized in that the cooling means includes a freezing means (10) for freezing the droplets on the substrate, and the heating means is an evaporation means (11) for evaporating the droplets on the substrate. And the control means causes the droplet supply means, the freezing means, and the evaporation means to execute the supply of the droplets to the substrate, the freezing of the droplets, and the evaporation of the droplets a plurality of times in this order. A substrate processing apparatus according to claim 13. According to this configuration, it is possible to achieve the same effect as the effect described with respect to the invention of claim 5.

  The invention according to claim 15 is characterized in that the cooling means includes a cooling nozzle (18) for supplying a coolant only to a partial region in a main surface of the substrate held by the substrate holding means, The means supplies the heating agent to only a part of the main surface of the substrate held by the substrate holding means and irradiates the substrate held by the substrate holding means with infrared rays. The infrared irradiation means (30) and at least one of a heat generating member (31) capable of contacting only a droplet on the main surface of the substrate held by the substrate holding means. It is a substrate processing apparatus as described in any one.

  The coolant is a substance having a temperature lower than that of the heating agent. For example, the coolant is a material having a temperature lower than room temperature, and the heating agent is a material having a temperature higher than room temperature. The coolant may be a gas, a liquid, or a solid. The same applies to the heating agent. The coolant discharged from the cooling nozzle is supplied only to a partial region in the main surface of the substrate. Therefore, the coolant can be supplied only to the region where the droplet exists. Therefore, the droplet on the substrate can be selectively cooled. Similarly, when the heating nozzle is included in the heating means, the heating agent discharged from the heating nozzle is supplied only to a partial region in the main surface of the substrate. Therefore, the heating agent can be supplied only to the region where the droplet exists. Therefore, the droplet on the substrate can be selectively heated.

  In addition, when the infrared irradiation means is included in the heating means, infrared rays from the infrared irradiation means are irradiated onto the substrate. When the substrate held by the substrate holding means is a silicon substrate and the droplets supplied to the substrate are formed of a liquid containing water, the infrared wavelength emitted by the infrared irradiation means is about 3 μm to less than 4 μm. Preferably there is. That is, as described in Patent Document 2, for example, infrared rays having a wavelength within this range are hardly absorbed by the silicon substrate and pass through the silicon substrate. On the other hand, infrared rays having a wavelength within this range are efficiently absorbed by a liquid containing water. Therefore, when the substrate is irradiated with infrared rays having a wavelength within this range, only the liquid on the substrate is heated. Therefore, the droplet on the substrate can be selectively heated.

  When the heating member is included in the heating means, the heating member contacts only the droplet on the substrate, and only the droplet is heated. Therefore, the droplet on the substrate can be selectively heated. Thus, according to this structure, the droplet on the substrate can be selectively cooled and heated. Therefore, similarly to the sixth aspect of the invention, the adhesion of foreign matter to the substrate can be reduced, and the running cost can be reduced.

  According to a sixteenth aspect of the present invention, the droplet supply unit includes a droplet nozzle (15) for discharging a droplet and a droplet nozzle moving unit (16) for moving the droplet nozzle, and the substrate The processing apparatus includes a contamination state measuring means (7) for identifying a contaminated portion where foreign matter is adhered to the main surface of the substrate held by the substrate holding means, and the output based on the output from the contamination state measuring means. Control means (5) which further positions a supply position of a droplet from the droplet nozzle in the contaminated part by controlling a droplet nozzle moving means, according to any one of claims 10 to 15. It is a substrate processing apparatus of description.

  According to this configuration, the contaminated portion on the main surface of the substrate where foreign matter is attached is specified by the contamination state measuring means. The control device controls the droplet nozzle moving unit based on the output from the contamination state measuring unit, thereby positioning the droplet supply position (target position) with respect to the main surface of the substrate in the contaminated portion. In this state, the control device discharges droplets from the droplet nozzle toward the contaminated portion. Thereby, a droplet is supplied only to a contaminated part. Therefore, similarly to the seventh aspect of the invention, the adhesion of foreign matter to the substrate can be reduced, and the running cost can be reduced.

The invention described in claim 17 is configured such that the droplet supply means supplies the droplet to a predetermined portion in the main surface of the substrate held by the substrate holding means. Item 16. The substrate processing apparatus according to any one of Items 10 to 15. With this configuration, it is possible to achieve the same effect as that described in regard to the invention of claim 8.
According to an eighteenth aspect of the present invention, the droplet supply means causes the droplet of the corrosive liquid that corrodes the main surface of the substrate to be only in a partial region within the main surface of the substrate held by the substrate holding means. The substrate processing apparatus according to claim 10, wherein the substrate processing apparatus is supplied. According to this configuration, it is possible to achieve the same effect as that described in regard to the invention of claim 9.

The invention according to claim 19 is the substrate processing apparatus according to any one of claims 10 to 18, wherein the droplet supply means includes a pipette (15) for dropping a liquid.
According to this configuration, a small amount of liquid is dropped from the pipette. Thereby, the droplet is supplied only to a partial region of the main surface of the substrate held by the substrate holding means. In addition, since the liquid is dripped, the liquid is surely supplied to the target position by dropping the liquid from the pipette with the pipette positioned above the predetermined position (target position) in the main surface of the substrate. it can. Furthermore, since the amount of liquid supplied to the substrate is small, substances and energy that change the temperature of the droplets can be reduced. Thereby, the cost of the substrate processing apparatus can be reduced.

  In this section, alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

1 is a schematic plan view of a substrate processing apparatus according to an embodiment of the present invention. It is the schematic diagram which looked at the inside of the processing unit which concerns on one Embodiment of this invention from the horizontal direction. It is process drawing for demonstrating the process example of the board | substrate which concerns on one Embodiment of this invention. It is process drawing for demonstrating the said process example. It is process drawing for demonstrating the said process example. It is process drawing for demonstrating the said process example. It is process drawing for demonstrating the said process example. It is process drawing for demonstrating the said process example. It is a schematic diagram for demonstrating the modification of one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic plan view of a substrate processing apparatus 1 according to an embodiment of the present invention.
The substrate processing apparatus 1 is a single-wafer type substrate processing apparatus that processes a disk-shaped substrate W such as a semiconductor wafer one by one. The substrate processing apparatus 1 includes a load port 2 that holds a plurality of carriers C that accommodate a substrate W, a substrate delivery unit 3 that delivers the substrate W, and a plurality of processing units 4 that process the substrate W. The load port 2 and the processing unit 4 are arranged at an interval in the horizontal direction. The substrate delivery unit 3 is disposed on the transport path of the substrate W transported between the load port 2 and the processing unit 4. The substrate processing apparatus 1 further includes an indexer robot IR disposed between the load port 2 and the substrate delivery unit 3, a main robot MR disposed between the substrate delivery unit 3 and the processing unit 4, and a substrate processing. And a control device 5 (control means) for controlling the operation of the device provided in the device 1 and the opening and closing of the valve.

The indexer robot IR includes a U-shaped hand _HIR in plan view that holds the substrate W horizontally while being supported. The indexer robot IR moves the hand _HIR in the horizontal direction and the vertical direction. Further, the indexer robot IR, by rotating (rotation) about a vertical axis, to change the orientation of the hand H _IR. The plurality of carriers C are arranged in the horizontal arrangement direction D1. The indexer robot IR moves in the arrangement direction D1. Indexer robot IR by movement and rotation of the arrangement direction D1, is opposed to the hand H _IR to any carrier C and the substrate transfer unit 3. The indexer robot IR by the movement of the horizontal and vertical directions of the hand H _IR, carries operations in the carrier C and the substrate transfer unit 3 carries the substrate W, and a carrier C and the substrate transfer unit 3 transports the substrate W Carry out the unloading operation. The indexer robot IR transports the substrate W between the carrier C and the substrate delivery unit 3.

Similarly, the main robot MR includes a U-shaped hand _HMR in plan view that holds the substrate W horizontally while being supported. The main robot MR moves the hand _HMR in the horizontal direction and the vertical direction. Further, the main robot MR, by rotating (rotation) about a vertical axis, to change the orientation of the hand H _MR. The main robot MR is disposed between the plurality of processing units 4. The main robot MR, is opposed to the hand H _MR to any processing unit 4 and the substrate transfer unit 3 by the rotation. The main robot MR, by the movement of the horizontal and vertical directions of the hand H _MR, carrying operation for carrying the substrate W to the processing unit 4 and the substrate transfer unit 3, and a processing unit 4 and the substrate W from the substrate transfer unit 3 Carry out the unloading operation. The main robot MR transports the substrate W between the processing unit 4 and the substrate delivery unit 3.

The substrate delivery unit 3 includes a plurality of support pins 6 that horizontally support the substrate W, and a measurement unit 7 (contamination state measurement means) that measures the contamination state of the substrate W supported by the plurality of support pins 6. . The support pins 6 and the measurement unit 7 are disposed inside the board delivery unit 3. Although not shown, the support pin 6 has an upward convex conical shape having a hemispherical tip. The tips of the plurality of support pins 6 are arranged along a circle smaller than the diameter of the substrate W surrounding the center position P1. The height of the tip of each support pin 6 is equal. The substrate W is supported in a horizontal posture by point contact between the tip end portions of the support pins 6 and the lower surface peripheral edge portion of the substrate W. Indexer robot IR and the main robot MR, by the hand _{H IR} and hand _{H MR} place the substrate W on the support pins 6, lift the substrate W supported by the support pins 6 by the hand _{H IR} and hand _{H MR.} The indexer robot IR and the main robot MR pass the substrate W to the support pins 6 so that the center of the substrate W is positioned on the vertical axis passing through the center position P1.

  The measurement unit 7 is a unit that measures the number of foreign matters such as particles attached to the substrate W and the position of each foreign matter with respect to the substrate W. The measurement unit 7 includes, for example, a particle counter, a total reflection X-ray fluorescence analyzer (TRXRF), an energy dispersive X-ray analyzer (EDX: Energy Dispersive X-ray spectrometer), and a scanning electron microscope (SEM: Scanning Electron Microscope). , And at least one of image recognition foreign matter inspection devices. For example, the measurement unit 7 is configured to detect the foreign matter based on the radial distance from the center of the upper surface of the substrate W to the foreign matter and the distance in the circumferential direction from the notch or orientation flat provided on the peripheral edge of the substrate W to the foreign matter. Identify the location. Then, the measurement unit 7 outputs the position of the foreign object to the control device 5 as position information. As will be described later, the control device 5 acquires the measurement result of the measurement unit 7 and causes the processing unit 4 to process the substrate W based on the measurement result.

FIG. 2 is a schematic view of the inside of the processing unit 4 according to an embodiment of the present invention viewed from the horizontal direction.
The processing unit 4 is a single-wafer type unit that processes the substrates W one by one. The processing unit 4 includes a spin chuck 8 (substrate holding means) that horizontally holds and rotates the substrate W, and a droplet that holds a droplet on an arbitrary portion of the upper surface of the substrate W held by the spin chuck 8. Supply unit 9 (droplet supply means), cooling unit 10 (temperature changing means, cooling means, freezing means) for cooling the droplets held on the substrate W, and heating the droplets held on the substrate W Heating unit 11 (temperature changing means, heating means, thawing means, evaporation means) and a rinsing unit 12 for supplying a rinsing liquid to the upper surface of the substrate W held by the spin chuck 8.

  The spin chuck 8 holds the substrate W horizontally and rotates the disc base spin base 13 that can rotate around a vertical rotation axis A1 passing through the center of the substrate W, and the spin base 13 around the rotation axis A1. A spin motor 14. The spin chuck 8 may be a holding chuck that holds the substrate W horizontally with the substrate W held in the horizontal direction, or by adsorbing the back surface (lower surface) of the substrate W that is a non-device forming surface. A vacuum chuck that holds the substrate W horizontally may be used. FIG. 2 shows a case where the spin chuck 8 is a clamping chuck. The contact portion (for example, the spin base 13) in contact with the liquid supplied to the substrate W in the spin chuck 8 may be formed of a chemical resistant material having chemical resistance such as a synthetic resin, or a metal such as stainless steel. It may be formed. When a corrosive liquid containing a corrosive component that corrodes a metal such as a chemical liquid is supplied to the substrate W, the contact portion is formed of a chemical resistant material. On the other hand, when only the liquid not containing a corrosive component is supplied to the substrate W, the contact portion may be formed of a material other than a chemical resistant material such as a metal.

The droplet supply unit 9 includes a droplet nozzle 15 (pipette) that discharges droplets and a nozzle moving unit 16 (droplet nozzle moving means) that moves the droplet nozzle 15. The droplet nozzle 15 is, for example, an electric micropipette that discharges a small amount of liquid. A predetermined amount of liquid is stored inside the droplet nozzle 15. The liquid stored in the droplet nozzle 15 may be a liquid containing water, an organic solvent, an alcohol, or another liquid such as a chemical liquid. Good. Specifically, the liquid stored in the droplet nozzle 15 may be pure water (deionized water) which is an example of a liquid containing water, or SC-1 (NH ₄₎ which is an example of a chemical solution. An aqueous solution containing OH and H ₂ O ₂ may be used. SC-1 is an example of a corrosive liquid containing a corrosive component that corrodes the substrate W.

  The control device 5 drives the actuator 17 built in the droplet nozzle 15 to drop a small amount of liquid from the lower end of the droplet nozzle 15. The amount of liquid discharged from the droplet nozzle 15 at a time is, for example, several picoliters to several microliters. The control device 5 controls the nozzle moving unit 16 so that the droplet discharged from the droplet nozzle 15 is deposited on the upper surface of the substrate W, and the droplet nozzle 15 is retracted from above the substrate W. The droplet nozzle 15 is moved between the retracted position. Although not shown, the nozzle moving unit 16 includes, for example, a motor and a transmission mechanism that transmits the power of the motor to the droplet nozzle 15. The control device 5 can supply droplets to any position within the upper surface of the substrate W by controlling the droplet nozzle 15 and the nozzle moving unit 16.

  The cooling unit 10 includes a cooling nozzle 18 that discharges a coolant that cools droplets held on the substrate W, a cooling pipe 19 that is connected to the cooling nozzle 18, and a cooling valve 20 that is interposed in the cooling pipe 19. And a nozzle moving unit 21 that moves the cooling nozzle 18. The coolant from the coolant supply source is supplied to the cooling nozzle 18 via the cooling pipe 19. Supply of the coolant to the cooling nozzle 18 is controlled by opening and closing the cooling valve 20. The cooling nozzle 18 discharges the coolant downward. The control device 5 controls the nozzle moving unit 21 so that the coolant discharged from the cooling nozzle 18 is sprayed onto a region in the upper surface of the substrate W, and the cooling nozzle 18 is retracted from above the substrate W. The cooling nozzle 18 is moved between the retracted positions. The coolant is, for example, a low-temperature substance within a range of −20 ° C. to room temperature. The temperature of the coolant is lower than the heating agent described later. The coolant may be liquid nitrogen, dry ice powder, or other substances.

  The heating unit 11 includes a heating nozzle 22 that discharges a heating agent that heats the droplets held on the substrate W, a heating pipe 23 connected to the heating nozzle 22, and a heating valve 24 interposed in the heating pipe 23. And a nozzle moving unit 25 that moves the heating nozzle 22. The heating agent from the heating agent supply source is supplied to the heating nozzle 22 via the heating pipe 23. Supply of the heating agent to the heating nozzle 22 is controlled by opening and closing the heating valve 24. The heating nozzle 22 discharges the heating agent downward. The control device 5 controls the nozzle moving unit 25 so that the heating agent discharged from the heating nozzle 22 is sprayed onto a region in the upper surface of the substrate W, and the heating nozzle 22 is retracted from above the substrate W. The heating nozzle 22 is moved between the retracted positions. The heating agent is, for example, a high-temperature gas in the range of room temperature to 130 ° C. The heating agent may be high-temperature air, high-temperature steam, or other gas.

  The rinsing unit 12 includes a rinsing liquid nozzle 26 for discharging a rinsing liquid, a rinsing liquid pipe 27 connected to the rinsing liquid nozzle 26, a rinsing liquid valve 28 interposed in the rinsing liquid pipe 27, and the rinsing liquid nozzle 26. And a nozzle moving unit 29 to be moved. The rinse liquid from the rinse liquid supply source is supplied to the rinse liquid nozzle 26 via the rinse liquid pipe 27. The supply of the rinse liquid to the rinse liquid nozzle 26 is controlled by opening and closing the rinse liquid valve 28. The rinse liquid nozzle 26 discharges the rinse liquid downward. The control device 5 controls the nozzle moving unit 29 so that the rinse liquid discharged from the rinse liquid nozzle 26 is deposited on the upper surface of the substrate W, and the rinse liquid nozzle 26 is retracted from above the substrate W. The rinse liquid nozzle 26 is moved between the retracted position. Examples of the rinsing liquid supplied to the rinsing liquid nozzle 26 include pure water, carbonated water, electrolytic ion water, hydrogen water, ozone water, and hydrochloric acid water having a diluted concentration (for example, about 10 to 100 ppm). .

3A to 3F are process diagrams for explaining a processing example of the substrate W according to the embodiment of the present invention. In the following, reference is made to FIG. 1 and FIG. 3A to 3F will be referred to as appropriate.
When the substrate W is processed by the substrate processing apparatus 1, the control device 5 unloads the substrate W from the carrier C and loads the substrate W into the substrate delivery unit 3 by the indexer robot IR. Then, as illustrated in FIG. 3A, the control device 5 causes the measurement unit 7 to measure the contamination state of the substrate W (contamination state measurement step). As a result, the position of the foreign matter adhering to the upper surface of the substrate W is measured, and position information indicating the position of the foreign matter within the upper surface of the substrate W is output from the measurement unit 7 to the control device 5. After the contamination state of the substrate W is measured by the measurement unit 7, the control device 5 unloads the substrate W from the substrate delivery unit 3 by the main robot MR and loads the substrate W into the processing unit 4. Thereby, the substrate W is held in a horizontal posture by the spin chuck 8.

  Next, a droplet supply process is performed in which a small amount of liquid is supplied only to the contaminated portion (the portion where the substrate W and the foreign matter are in contact with each other and the peripheral portion thereof) on the upper surface of the substrate W. Specifically, the control device 5 controls the nozzle moving unit 16 based on the position information acquired from the measurement unit 7 to move the droplet nozzle 15 to a predetermined position where the droplet reaches the contaminated portion. . In this embodiment, since the liquid is discharged vertically downward from the droplet nozzle 15, the droplet nozzle 15 is disposed above the foreign matter. When the droplet nozzle 15 is moved to a predetermined position, the control device 5 may rotate the substrate W by controlling the spin chuck 8 in addition to the movement of the droplet nozzle 15 or rotate the substrate W. Alternatively, only the droplet nozzle 15 may be moved. That is, the liquid landing position may be moved to the contaminated portion by moving only the droplet nozzle 15 or the substrate W, or the liquid landing position by moving both the droplet nozzle 15 and the substrate W. May be moved to the contaminated part.

  As shown in FIG. 3B, the control device 5 drives the actuator 17 incorporated in the droplet nozzle 15 after the droplet nozzle 15 has moved to a predetermined position, thereby causing SC-1 as an example of the liquid. The ink is discharged from the droplet nozzle 15 toward the upper surface of the substrate W. Since the amount of liquid ejected from the droplet nozzle 15 is small, when SC-1 is ejected from the droplet nozzle 15, SC-1 is supplied only to the contaminated portion. Thereby, as shown in an enlarged manner in FIG. 3B, the foreign matter (particle) is covered with SC-1. When a plurality of foreign matters are adhered to the substrate W, the control device 5 causes the droplet nozzle 15 and the like to perform the operations from the movement of the droplet nozzle 15 to the supply of SC-1 again, and the droplet Droplets are ejected from the nozzle 15 toward each foreign object. Thereby, a plurality of droplets are held on the upper surface of the substrate W, and each foreign substance is covered with SC-1. Then, after all the foreign matter is covered with SC-1, the control device 5 controls the nozzle moving unit 16 to retract the droplet nozzle 15 from above the substrate W.

  Next, a freezing process (cooling process) for freezing droplets on the substrate W is performed. Specifically, the control device 5 moves the cooling nozzle 18 to a predetermined position where the coolant is sprayed only on the contaminated portion by controlling the nozzle moving unit 21 based on the position information acquired from the measurement unit 7. At this time, the control device 5 may move only the cooling nozzle 18 as in the droplet supply step, or may rotate the substrate W in addition to the movement of the cooling nozzle 18. As illustrated in FIG. 3C, after the cooling nozzle 18 has moved to a predetermined position, the control device 5 opens the cooling valve 20 and discharges liquid nitrogen, which is an example of a coolant, from the cooling nozzle 18. The liquid nitrogen discharged from the cooling nozzle 18 is supplied to the foreign matter covered by the droplets of SC-1, and lowers the temperature of the foreign matter and SC-1 to a temperature lower than room temperature. Thereby, SC-1 freezes with a foreign object instantly. After the SC-1 freezes, the control device 5 closes the cooling valve 20 and stops the discharge of liquid nitrogen from the cooling nozzle 18. When a plurality of foreign matters are attached to the substrate W, the control device 5 causes the cooling nozzle 18 and the like to perform the operations from the movement of the cooling nozzle 18 until the supply of liquid nitrogen is stopped. Liquid nitrogen is discharged toward each foreign object. Thereby, all the droplets on the substrate W are frozen. Then, after all the droplets are frozen, the control device 5 controls the nozzle moving unit 21 to retract the cooling nozzle 18 from above the substrate W.

  Next, a thawing process (heating process, evaporation process) for evaporating droplets on the substrate W is performed. Specifically, the control device 5 controls the nozzle moving unit 25 based on the position information acquired from the measurement unit 7 to move the heating nozzle 22 to a predetermined position where the heating agent is sprayed only on the contaminated portion. At this time, the control device 5 may move only the heating nozzle 22 as in the droplet supply step, or may rotate the substrate W in addition to the movement of the heating nozzle 22. As shown in FIG. 3D, after the heating nozzle 22 has moved to a predetermined position, the control device 5 opens the heating valve 24 and discharges high-temperature steam near 100 ° C., which is an example of a heating agent, from the heating nozzle 22. . The high-temperature water vapor discharged from the heating nozzle 22 is sprayed on the foreign matter covered by the SC-1 droplets, and raises the temperature of the foreign matter and SC-1 to a temperature higher than room temperature. Thereby, SC-1 in a frozen state is melted and instantly evaporated. After SC-1 evaporates, control device 5 closes heating valve 24 and stops the discharge of water vapor from heating nozzle 22. When a plurality of foreign matters are adhered to the substrate W, the control device 5 causes the heating nozzle 22 and the like to perform the operations from the movement of the heating nozzle 22 to the stop of the supply of water vapor to each foreign matter from the heating nozzle 22 again. High-temperature water vapor is discharged toward As a result, all SC-1 on the substrate W evaporates, and the SC-1 disappears from the substrate W. Then, after all the droplets have evaporated, the control device 5 controls the nozzle moving unit 25 to retract the heating nozzle 22 from above the substrate W.

  Next, a repeated process of freezing and evaporating the droplets on the substrate W is performed. Specifically, the control device 5 supplies droplets to the contaminated portion in the same manner as the above-described droplet supply step. Thereafter, the control device 5 supplies the coolant to the contaminated portion in the same manner as the above-described freezing step. Thereafter, the control device 5 causes the heating agent to be supplied to the contaminated portion in the same manner as the above-described thawing step. Therefore, one cycle from the droplet supply process to the thawing process is repeated. The number of repetitions of this cycle may be one or two or more. Further, the liquid supplied to the substrate W in the second and subsequent droplet supply processes may be the same type of liquid as the liquid supplied to the substrate W in the previous droplet supply process, or a different type of liquid. It may be a liquid. The same applies to the coolant and the heating agent.

  Next, a rinsing process is performed in which foreign matter on the substrate W is washed away with a rinsing liquid. Specifically, the control device 5 controls the spin chuck 8 to rotate the substrate W around the rotation axis A1. Thereafter, the control device 5 controls the nozzle moving unit 29 to move the rinse liquid nozzle 26 to a predetermined position where the rinse liquid is deposited on the upper surface of the substrate W. As shown in FIG. 3E, the control device 5 opens the rinse liquid valve 28 after the rinse liquid nozzle 26 has moved to a predetermined position, and discharges pure water as an example of the rinse liquid from the rinse liquid nozzle 26. At this time, the control device 5 may discharge pure water while moving the rinsing liquid nozzle 26, or may discharge pure water without moving the rinsing liquid nozzle 26. The pure water discharged from the rinsing liquid nozzle 26 is supplied to the upper surface of the substrate W, receives a centrifugal force due to the rotation of the substrate W, and spreads outward along the upper surface of the substrate W. Thereby, pure water is supplied to the entire upper surface of the substrate W, and the foreign matter on the substrate W is washed away. When a predetermined time elapses after the rinsing liquid valve 28 is opened, the control device 5 closes the rinsing liquid valve 28 and stops discharging pure water from the rinsing liquid nozzle 26. Thereafter, the control device 5 controls the nozzle moving unit 29 to retract the rinsing liquid nozzle 26 from above the substrate W.

  Next, a drying process (spin drying) for drying the substrate W is performed. Specifically, the control device 5 controls the spin chuck 8 to rotate the substrate W at a high rotation speed (for example, several thousand rpm). 3F, a large centrifugal force acts on the pure water adhering to the substrate W, and the pure water adhering to the substrate W is shaken off around the substrate W. In this way, pure water is removed from the substrate W, and the substrate W is dried. Then, after the drying process is performed for a predetermined time, the control device 5 controls the spin chuck 8 to stop the rotation of the substrate W. Thereafter, the control device 5 causes the main robot MR to carry out the processed substrate W from the processing unit 4, and loads the substrate W into the substrate delivery unit 3. And the control apparatus 5 carries out the processed board | substrate W from the board | substrate delivery unit 3 by the indexer robot IR, and carries this board | substrate W in one of the carriers C. The control device 5 causes the indexer robot IR or the like to repeatedly execute this series of operations, thereby processing a plurality of substrates W one by one.

  As described above, in the present embodiment, the droplet is held only in a part of the upper surface of the substrate W, and the droplet is frozen and evaporated. The foreign matter on the substrate W in contact with the droplet is cooled in the process of freezing the droplet and heated in the process of evaporating the droplet. Therefore, the foreign matter on the substrate W repeatedly contracts and expands by repeatedly freezing and evaporating the droplets. When the foreign matter contracts or expands, stress is generated between the substrate W and the foreign matter, and the adhesion force of the foreign matter to the substrate W is reduced. As a result, the foreign matter is easily peeled off from the substrate W.

  Furthermore, since the coolant and the heating agent are discharged toward the droplets on the substrate W, only the droplets are selectively cooled and heated. For this reason, only the temperature of the droplet and the foreign matter changes greatly, and the temperature of the substrate W hardly changes. For example, when the temperature of both the foreign matter and the substrate W is significantly increased, both the foreign matter and the substrate W are greatly expanded. Therefore, the relative displacement amount at the contact portion between the foreign matter and the substrate W is only the foreign matter. Is smaller than when it expands. Therefore, only the droplets on the substrate W are selectively cooled and heated, so that the adhesion of foreign matter to the substrate W is further reduced. As a result, the foreign matter is more easily peeled off from the substrate W.

  Furthermore, since the SC-1 droplet that corrodes the substrate W is supplied to the upper surface of the substrate W, the surface layer of the substrate W is corroded (melted) by the SC-1. Therefore, the adhesion force of the foreign matter to the substrate W is further reduced, or the foreign matter is peeled off from the substrate W (lift-off). Therefore, the substrate W is in a state where foreign substances can be easily removed. Therefore, when the rinsing liquid is supplied to the substrate W, all foreign matters on the substrate W are washed away, and foreign matters are reliably removed from the substrate W. Thereby, the cleanliness of the substrate W can be improved.

  In addition, since the liquid droplets are supplied to only a part of the upper surface of the substrate W, the amount of liquid consumption is less than when the liquid is supplied to the entire upper surface of the substrate W. Furthermore, since the amount of liquid held on the substrate W is small, the droplets can be cooled and heated with a small amount of coolant and heating agent. Therefore, consumption of the coolant and the heating agent can be reduced. Therefore, the running cost of the substrate processing apparatus 1 can be reduced. Furthermore, since the amount of liquid held on the substrate W is small, the droplets can be frozen and evaporated in a short time. Therefore, the processing time of the substrate W can be shortened. Furthermore, since the liquid such as SC-1 is supplied only to the area where the foreign matter exists, it is possible to suppress or prevent the occurrence of damage to the area in the upper surface of the substrate W where it is not necessary to supply the liquid.

  Further, since the adhesion of foreign matter to the substrate W is reduced by cooling and heating the droplets, it is not necessary to supply the droplets of the corrosive liquid such as SC-1 to the substrate W. That is, for example, even if pure water is used instead of SC-1 in the above processing example, foreign matter can be reliably removed from the substrate W. As described above, when only the liquid not containing the corrosive component is supplied to the substrate W, the contact portion in contact with the liquid supplied to the substrate W in the spin chuck 8 can be formed of a material other than the chemical resistant material such as metal. . That is, the contact portion can be formed of a material that is more workable than a synthetic resin such as stainless steel. Thereby, the manufacturing cost of the substrate processing apparatus 1 can be reduced. Furthermore, since the deterioration of the substrate processing apparatus 1 due to corrosion can be prevented, the product life of the substrate processing apparatus 1 can be extended.

Although the description of the embodiment of the present invention has been described above, the present invention is not limited to the contents of the above-described embodiment, and various modifications can be made within the scope of the claims.
For example, in the above-described embodiment, the case where the droplet on the substrate W is heated by the heating agent has been described, but the method for heating the droplet is not limited thereto.
Specifically, as shown in FIG. 4, for example, infrared rays having a wavelength of about 3 μm to less than 4 μm are irradiated to the entire area of the substrate W from an infrared irradiation unit 30 (infrared irradiation means) built in the spin base 13. Also good. When the substrate W held by the spin chuck 8 is, for example, a silicon substrate, infrared rays having a wavelength within this range are hardly absorbed by the silicon substrate and pass through the silicon substrate. On the other hand, when the droplet on the substrate W is formed of a liquid containing water, infrared rays having a wavelength within this range are efficiently absorbed by the droplet. Accordingly, when the entire area of the substrate W is irradiated with infrared rays having a wavelength within this range, only the droplets on the substrate W are heated. Therefore, the droplets on the substrate W can be selectively heated.

Further, the droplet on the substrate W may be heated by a heat generating member that can contact only the droplet. Specifically, as shown in FIG. 4, the control device 5 moves the heat probe 31 (heat generating member) that generates heat by the heat generating member moving unit 32, thereby moving the tip of the heat probe 31 to the liquid on the substrate W. The droplets on the substrate W may be selectively heated in contact with only the droplets.
In the above processing example, the case where all the droplets are removed from the substrate W by evaporating the frozen droplets has been described. For example, by changing the temperature of the heating agent and the supply time, The heating temperature of the droplets may be adjusted so that all the droplets from W are not lost. In this case, since the droplet does not disappear from the substrate W, it is not necessary to supply the droplet from the droplet nozzle 15 to the substrate W after heating the droplet. That is, even when the cooling and heating of the droplets are performed a plurality of times, the droplet supply step need not be performed a plurality of times. Therefore, the processing time of the substrate W can be shortened.

Further, in the processing example described above, the case where the substrate W is dried by the processing unit 4 and then transported to the carrier C has been described. However, the contamination state of the substrate W processed by the processing unit 4 is measured by the measurement unit. 7 may be measured again. When the cleanness of the substrate W is low, the substrate W may be processed again by the processing unit 4.
In the above-described processing example, the case where the area in the upper surface of the substrate W to which the droplet is supplied is set for each substrate W, but this area may be set in advance. For example, droplets may be supplied only to the peripheral edge of the upper surface of the substrate W. The peripheral edge of the upper surface of the substrate W is in contact with the transfer robots IR and MR and the spin chuck 8. Therefore, the peripheral edge of the upper surface of the substrate W is more easily contaminated than other regions of the substrate W. Therefore, the area where the droplets are supplied may be set to an area that is easily contaminated.

Moreover, although the above-mentioned embodiment demonstrated the case where the substrate processing apparatus 1 was an apparatus which processes the disk-shaped board | substrate W, the substrate processing apparatus 1 is a polygonal board | substrate, such as a board | substrate for liquid crystal display devices. It may be a device for processing.
In addition, various design changes can be made within the scope of matters described in the claims.

1: Substrate processing device 5: Control device (control means)
7: Measuring unit (contamination state measuring means)
8: Spin chuck (substrate holding means)
9: Droplet supply unit (droplet supply means)
10: Cooling unit (temperature changing means, cooling means, freezing means)
11: Heating unit (temperature changing means, heating means, thawing means, evaporation means)
15: Droplet nozzle (pipette)
16: Nozzle moving unit (droplet nozzle moving means)
18: Cooling nozzle 22: Heating nozzle 30: Infrared irradiation unit (infrared irradiation means)
31: Thermal probe (heating member)
W: Substrate

Claims (19)

A droplet supply step for supplying droplets only to a partial region in the main surface of the substrate;
And a temperature changing step of changing a temperature of the droplet on the substrate.   The substrate processing method according to claim 1, wherein the temperature changing step includes a cooling step of cooling the droplets on the substrate and a heating step of heating the droplets on the substrate. The cooling step includes a freezing step of freezing the droplets on the substrate;
The substrate processing method according to claim 2, wherein the heating step includes a thawing step of thawing droplets on the substrate.   4. The substrate processing method according to claim 2, wherein the temperature changing step includes a repeating step in which cooling and heating of the droplet are alternately performed a plurality of times. The cooling step includes a freezing step of freezing the droplets on the substrate;
The heating step includes an evaporation step for evaporating droplets on the substrate,
The substrate processing method according to claim 4, wherein the substrate processing method includes a step of performing the droplet supply step, the freezing step, and the evaporation step a plurality of times in this order. The cooling step includes a selective cooling step of selectively cooling droplets on the substrate,
The substrate processing method according to claim 2, wherein the heating step includes a selective heating step of selectively heating droplets on the substrate. A contamination state measuring step for identifying a contaminated portion on the main surface of the substrate to which foreign matter is attached before the droplet supply step is performed;
The substrate processing method according to claim 1, wherein the droplet supply step includes a step of supplying a droplet only to the contaminated portion.   The substrate processing method according to claim 1, wherein the droplet supplying step includes a specific portion supplying step of supplying droplets to a predetermined portion in the main surface of the substrate.   The substrate treatment according to claim 1, wherein the droplet supplying step includes a step of supplying a droplet of a corrosive liquid that corrodes the substrate only to a partial region in the main surface of the substrate. Method. Substrate holding means for holding the substrate;
Droplet supply means for supplying droplets only to a partial region in the main surface of the substrate held by the substrate holding means;
And a temperature changing means for changing the temperature of the droplet on the substrate held by the substrate holding means.   The substrate processing apparatus according to claim 10, wherein the temperature changing unit includes a cooling unit that cools the droplets on the substrate and a heating unit that heats the droplets on the substrate. The cooling means includes a freezing means for freezing droplets on the substrate,
The substrate processing apparatus according to claim 11, wherein the heating unit includes a thawing unit that thaws droplets on the substrate.   The substrate processing apparatus according to claim 11, further comprising a control unit configured to alternately and repeatedly perform cooling and heating of the droplet by the cooling unit and the heating unit. The cooling means includes a freezing means for freezing droplets on the substrate,
The heating means includes an evaporation means for evaporating droplets on the substrate,
The control unit causes the droplet supply unit, the freezing unit, and the evaporation unit to execute supply of the droplet to the substrate, freezing of the droplet, and evaporation of the droplet in this order a plurality of times. 14. The substrate processing apparatus according to 13. The cooling means includes a cooling nozzle that supplies the coolant only to a partial region in the main surface of the substrate held by the substrate holding means,
The heating means includes a heating nozzle that supplies the heating agent only to a partial region within the main surface of the substrate held by the substrate holding means, and an infrared ray that irradiates the substrate held by the substrate holding means with infrared rays. 15. The apparatus according to claim 11, comprising at least one of an irradiation unit and a heating member that can contact only a droplet on a main surface of the substrate held by the substrate holding unit. Substrate processing equipment. The droplet supply means includes a droplet nozzle for discharging a droplet, and a droplet nozzle moving means for moving the droplet nozzle,
The substrate processing apparatus includes: a contamination state measuring unit that identifies a contaminated portion where foreign matter is attached to a main surface of the substrate held by the substrate holding unit; and the liquid based on an output from the contamination state measuring unit. The substrate processing according to claim 10, further comprising a control unit that controls a droplet nozzle moving unit to position a supply position of a droplet from the droplet nozzle in the contaminated portion. apparatus.   The droplet supply unit is configured to supply a droplet to a predetermined portion in a main surface of a substrate held by the substrate holding unit. 2. The substrate processing apparatus according to 1.   18. The droplet supply unit according to claim 10, wherein a droplet of a corrosive liquid that corrodes the main surface of the substrate is supplied only to a partial region in the main surface of the substrate held by the substrate holding unit. The substrate processing apparatus as described in any one of Claims.   The substrate processing apparatus according to claim 10, wherein the droplet supply unit includes a pipette that drops liquid.

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