JP4421290B2 - Bellows pump and resist coating apparatus using the same - Google Patents

Description

  The present invention relates to a bellows pump used for liquid supply and a resist coating apparatus using the same.

  Conventionally, for example, a bellows pump has been used to supply a chemical solution or the like during various processes in a semiconductor manufacturing process (see Patent Documents 1 to 3). Further, in the lithography process during the manufacture of a liquid crystal display, a bellows pump is used to feed the resist solution from the resist solution storage section to the nozzle when the resist solution is dropped onto the substrate from the nozzle and applied. .

  An example of a resist coating apparatus using such a bellows pump is shown in FIG. This resist coating apparatus is used for coating on a substrate by a spin coating method. A bellows pump 101 provided in this apparatus has a housing 127 in which a pump chamber 126 is formed, a suction port 107 and a discharge port. 108 has been established. The suction port 107 communicates with the resist solution reservoir 147 through the suction pipe 150, and the discharge port 108 communicates with the discharge nozzle 151 through the supply pipe 148. The suction port 107 is provided with a suction-side check valve 111 that allows only the resist solution to flow into the pump chamber 126, and the discharge port 108 has a discharge side that allows only the resist solution to flow out from the pump chamber 126. A check valve 112 is provided.

A bellows 103 is provided in the housing 127 and is configured to expand and contract by moving the drive member 152 in the axial direction. By contracting the bellows 103 in the axial direction, the resist solution from the resist solution reservoir 147 is sucked into the pump chamber 126. On the other hand, by extending the bellows 103 in the axial direction, the pump chamber 126 is pressurized and the resist solution is discharged from the discharge nozzle 151 and supplied to the substrate 149.
JP 2001-153051 A JP 2000-45952 A JP-A-11-107925

  In the bellows pump 101 having the structure as shown in the figure, the opening of the pump chamber 126 communicating with the suction port 107 and the discharge port 108 is provided at a position spaced from the bellows portion 153 of the bellows 103. However, in such a structure, the flow of the resist solution into and out of the pump chamber 126 due to the expansion and contraction of the bellows 103 by the driving member 152 does not sufficiently reach the bellows portion 153 of the bellows 103, so Tends to stay.

  For this reason, the resist solution that stays for a long time may deteriorate due to oxidation, gelation, or the like, or microbubbles may be generated. The deteriorated resist solution may clog the discharge port 108 or the like, or the residual bubbles may suddenly be discharged. As a result, a defect (resist failure) may occur in the resist film.

  The present invention has been made to solve the above-described problems in the prior art, and its purpose is to provide a bellows pump capable of quickly discharging liquid and bubbles remaining in the bellows portion to the outside of the pump chamber, Another object is to provide a resist coating apparatus using the same.

The bellows pump of the present invention includes a pump head provided with a suction port for sucking liquid and a discharge port for discharging the liquid;
A telescopic bellows attached to the pump head;
The pump chamber communicated with the suction port and the discharge port, and defined by the bellows,
A bellows pump that sucks and discharges the liquid through the suction port and the discharge port by driving the bellows in a telescopic axis direction,
The pump head is provided with a protrusion that extends toward the pump chamber of the bellows,
In the vicinity of the fixed end of the bellows, a horizontal opening of the protrusion is provided,
The opening end of the horizontal opening is formed so as to open facing the bellows at a position that coincides with the bottom surface of the pump chamber on the pump head side.
When the bellows is driven to extend, the liquid flows into the pump chamber in a direction substantially perpendicular to the direction of the bellows expansion and contraction, and when the bellows is driven to contract, the liquid is bellows outside the pump chamber. It is configured to flow out in a direction substantially perpendicular to the direction of the telescopic axis.

  In the present invention configured as described above, a gap along the bellows portion is formed between the protruding portion and the bellows portion of the bellows, and a liquid such as a resist solution fed by a pump is formed in the protruding portion. While flowing in and out through the horizontal opening, at the time of liquid inhalation, the liquid is sucked so that the liquid and bubbles staying in the bellows part are drawn and pushed down into the pump chamber by the downward flow along the bellows part passing through this gap Is done. On the other hand, when the liquid is discharged, the liquid and bubbles staying in the bellows part are drawn by the upward flow along the bellows part passing through the gap, and the liquid is discharged by pushing it up to the horizontal opening side.

  Therefore, the liquid and bubbles staying in the bellows part can be reliably and rapidly discharged out of the pump chamber.

The horizontal opening of the protrusion is provided in the vicinity of the fixed end of the bellows, and the opening end of the horizontal opening is formed to be opposed to the bellows at a position that coincides with the bottom surface of the pump chamber on the pump head side. As a result, the flow of pushing out the liquid and bubbles remaining in the bellows portion through the gap between the protrusion and the bellows portion reaches the fixed end side end portion of the bellows portion. Thus, the liquid and bubbles remaining in the bellows part can be reliably and quickly discharged out of the pump chamber.

  Moreover, it is preferable that a protrusion part is a column shape and multiple horizontal openings are formed in the side periphery part of a protrusion part. As a result, a sufficient flow for pushing out the liquid and bubbles staying in the bellows part over the entire gap having a substantially annular cross section formed between the bellows and the columnar protruding part is generated and stays in the bellows part. The liquid and bubbles that are present can be discharged out of the pump chamber reliably and quickly.

  In the bellows pump according to the present invention, a vertical opening is formed in the tip of the protruding portion so that the liquid flows into the pump chamber in a direction substantially parallel to the expansion / contraction axis direction of the bellows when the bellows is extended. It is characterized by being.

  In the present invention configured as described above, a part of the liquid sucked into the pump chamber flows from the vertical opening during the liquid suction. The liquid from the vertical opening is a fresh liquid, unlike the liquid staying in the bellows part through the gap between the protrusion and the bellows part from the horizontal opening and the liquid flowing into the pump chamber by drawing bubbles. Therefore, at the time of discharging the liquid, it is possible to draw in the liquid and bubbles that have stayed in the bellows through the gap between the protrusion and the bellows using a stagnant liquid and a fresh liquid with few bubbles, and push it out of the pump chamber through the horizontal opening.

  Therefore, the liquid and air bubbles staying in the bellows part can be reliably and quickly discharged out of the pump chamber.

In addition, when the bellows pump of the present invention is used in a so-called spinless resist coating apparatus, as will be described later, it is formed of a resin material such as a fluororesin by pressurizing with a resist solution in the pump chamber when discharging the resist solution. In order to prevent the deformed bellows portion from being deformed, it is preferable to provide a bellows protective member fitted to the outer concave portion of the bellows portion on the bellows outer peripheral portion. However, when the resist solution is inhaled, negative pressure is generated in the pump chamber, and the negative pressure in the pump chamber may deform the outer convex portion of the bellows portion. This bellows protection member prevents this deformation. Can not do it.

  However, by providing a vertical opening at the tip of the protrusion, it is possible to increase the liquid flow rate into the pump chamber when the resist solution is inhaled. Therefore, deformation of the outer convex portion of the bellows portion is suppressed, and residual deformation of the bellows portion is suppressed. Can prevent damage, etc.

  The bellows pump of the present invention opens the flow path when the bellows is extended and driven from the vertical opening to the liquid flow path formed inside the projecting portion. And a check valve that closes the flow path and prevents the liquid from flowing out of the pump chamber when the bellows is driven to contract. Features.

  In the present invention configured as above, the flow path from the vertical opening is opened at the time of liquid inhalation, and fresh liquid flows from the vertical opening as described above, while the flow from the vertical opening by the check valve at the time of liquid discharge. The passage is closed, and the outflow of liquid from the vertical opening to the outside of the pump chamber is prevented. For this reason, all the liquid in the pump chamber is drawn out of the pump chamber through the horizontal opening by drawing in the liquid and air bubbles remaining in the bellows portion through the gap between the protrusion and the bellows portion.

  Accordingly, fresh liquid can flow into the pump chamber during liquid inhalation, and all liquid in the pump chamber can be pushed out of the pump chamber from the horizontal opening by using this fresh liquid during liquid discharge, and is retained in the bellows portion. The liquid and bubbles can be discharged out of the pump chamber reliably and quickly.

  The bellows pump of the present invention described above is suitably used for a resist coating apparatus.

  According to the bellows pump and the resist coating apparatus using the bellows pump of the present invention, the liquid and bubbles remaining in the bellows can be quickly discharged out of the pump chamber.

  Hereinafter, the present invention will be described in detail with reference to the drawings. 1 is a cross-sectional view of a bellows pump according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the bellows pump of FIG. 1 taken along line AA, FIG. 3 is a state of the bellows pump of FIG. FIG. 4 shows a state when the bellows pump of FIG.

  The bellows pump 1 of this embodiment shown in FIGS. 1 to 4 is used for a resist coating apparatus, and in particular, a resist solution discharge nozzle above a relatively large substrate such as an LCD substrate used in recent years. Is used for a so-called spinless method in which a resist solution is applied to a substrate surface with a desired film thickness by continuously discharging a thin-line resist solution while moving or scanning the substrate. It is a bellows pump having a large capacity and a high pressure resistance that can accommodate a minute amount of resist solution. The bellows pump 1 is usually used in a vertical position.

The bellows pump 1 includes a pump head 2 provided with a suction port 7 for sucking a resist solution and a discharge port 8 for discharging a resist solution, a telescopic bellows 3 attached to the pump head 2, a suction port 7, The pump chamber 6 communicates with the discharge port 8 and is defined by the bellows 3. In addition, 18 is a columnar support member that supports the pump head 2, and 19 is a fixed plate.

  The bellows 3 is attached to the pump head 2 at the fixed end 4 with a bellows pressing plate 16 with an O-ring 17 interposed therebetween. On the other hand, at the movable end 5, a ball screw mechanism including a ball screw 21 and a bearing 22 is attached via a bellows adapter 20, and thereby the bellows 3 is driven in the direction of the telescopic axis, whereby the suction port 7 and the discharge port 8 are connected. Liquid inhalation and ejection are performed.

  The pump head 2 is provided with a columnar protrusion 13 extending inward of the pump chamber 6. A horizontal opening 14 is formed in the projecting portion 13 so as to face a direction substantially perpendicular to the direction of the expansion and contraction axis of the bellows 3. Four horizontal openings 14 are provided in the side periphery at the base position of the cylinder at positions near the fixed end 4 of the bellows 3, and along the circumference as shown in the AA sectional view of FIG. 2. The openings 14 are arranged at equal intervals so as to face in four directions.

  On the other hand, a vertical opening 15 facing the direction substantially parallel to the direction of the expansion and contraction of the bellows 3 is formed at the tip of the protrusion 13.

  The resist solution is sucked into the pump chamber 6 from the horizontal opening 14 and the vertical opening 15 and discharged to the outside of the pump chamber 6.

  In the spinless method, a high discharge pressure is required because a resist solution discharge nozzle having a large number of discharge holes having a very small hole diameter (for example, about 100 μm) is used. Further, when the filter is passed through in order to remove the bubbles of the resist solution before discharging, a resistance pressure is generated by the filter. For this reason, the liquid pressure at the time of discharging the resist liquid becomes high (about 1 MPa at the maximum), and the high-pressure resist liquid in the pump chamber 6 is deformed so as to crush the outer concave portion 3a of the bellows portion of the bellows 3. This may cause residual deformation or damage due to repeated fatigue. Therefore, in this embodiment, a flange-shaped bellows protection member 30 is attached to the outer periphery of the bellows 3.

  FIG. 9A shows a bellows protection member of the bellows pump of FIG. 1, and FIG. 10 is an enlarged cross-sectional view taken along line AA. As shown in FIG. 10, in the bellows protection member 30, the cross-sectional contour of the end portion 31 along the inner periphery of the flange shape is substantially the same shape as the cross-sectional contour of the outer recess 3 a when the bellows 3 is contracted. It is formed in a bulging shape.

  That is, since the cross-sectional contour of the end portion 31 has a shape along the cross-sectional contour of the outer recessed portion 3a when the bellows 3 is contracted until the volume of the pump chamber 6 is minimized, the bellows 3 Since the applied pressure from the pump chamber 6 side is received by the end portion 31 along the shape of the outer recessed portion 3a under no pressure even under pressure when the resist solution is discharged, it is not deformed by the applied pressure. .

Therefore, the outer recess 3a does not cause residual deformation or breakage due to repeated suction and discharge fatigue caused by deformation during pressurization. Further, the relationship between the moving distance of the drive member in the ball screw mechanism for extending and retracting the bellows 3 and the resist solution discharge amount from the discharge port 8 is also the shape of the outer convex portion 3b of the bellows portion against the pressurization during discharge. Since the change is small, the linearity is good and the resist solution can be applied from the discharge nozzle 51 in a uniform application amount.

The bellows protection member 30 includes, for example, metal flange forming members 32a and 32b obtained by dividing the flange shape into two as shown in FIG. 9B, and a fixing member (fixing bracket) that fixes these to form a flange shape. 33, a screw 38). When the bellows protection member 30 is formed from these members and assembled to the outer concave portion 3a of the bellows portion, the outer concave portion is first formed by the two flange forming members 32a and 32b. 3a is clamped, and in this state, the fixing bracket 33 is overlapped so that the screw holes 34 coincide with each other, and are screwed and fixed by screws 38 from the back side in the drawing.

  Next, the suction and discharge operations of the bellows pump 1 configured as described above will be described. The flow of the liquid when the resist liquid is sucked into the pump is as shown in FIG. By pulling the movable end 5 by the ball screw mechanism and extending the bellows 3, the resist solution from the resist solution storage tank 47 flows from the suction port 7. At this time, the suction-side check valve 11 opens the flow path, the discharge-side check valve 12 closes the flow path, and the resist solution from the suction port 7 receives the pump chamber 6 from the horizontal opening 14 and the vertical opening 15. Inhaled.

  The resist solution that flows in in the horizontal direction from the horizontal opening 14 flows downward through an annular gap formed narrowly between the cylindrical side periphery of the protrusion 13 and the bellows 3 of the bellows 3. As described above, the horizontal opening 14 is provided in four directions at positions near the fixed end 4 of the bellows 3 on the side periphery at the base position of the cylinder. For this reason, a downward flow is generated along the bellows portion from the fixed end side end of the bellows portion of the bellows 3 over the entire gap formed between the protruding portion 13 and the bellows portion of the bellows 3. The liquid and bubbles staying in the inner part (inner recess) of the bellows part are drawn in by the flow along the part and pushed down into the pump chamber 6 to flow into the space below the projecting part 13 of the pump chamber 6. To do.

  On the other hand, the fresh resist solution that has flowed into the pump chamber 6 from the vertical opening 15 is stored in a space below the protruding portion 13 of the pump chamber 6 as it is.

The flow of the liquid when the resist liquid sucked into the pump chamber 6 in this way is discharged from the discharge nozzle 51 is as shown in FIG. That is, when the movable end 5 is pushed by the ball screw mechanism and the bellows 3 is contracted, the resist solution flows out of the pump chamber 6 from the horizontal opening 14 and the vertical opening 15. At this time, the discharge side check valve 12 opens the flow path, the suction side check valve 11 closes the flow path, and the resist solution flows out from the discharge port 8 and passes through the supply pipe 48 and from the discharge nozzle 51. Discharged.

  When discharged from the pump chamber 6 through the horizontal opening 14, the resist solution in the pump chamber 6 flows upward through an annular gap formed between the protruding portion 13 and the bellows portion of the bellows 3. At this time, the liquid and bubbles staying inside the bellows portion are drawn by the flow along the bellows portion, pushed up to the horizontal opening 14, and discharged outside the pump chamber 6.

  On the other hand, a part of the resist solution sucked into the pump chamber 6 is also discharged out of the pump chamber 6 through the vertical opening 15.

  Thus, in this embodiment, since the pump head 2 is provided with the columnar protrusion 13 extending inward of the pump chamber 6 and the plurality of horizontal openings 14 are formed at the base of the side periphery, the protrusion A narrow gap is formed between the portion 13 and the bellows portion of the bellows 3, and the liquid and bubbles staying inside the bellows portion are drawn by the flow along the bellows portion passing through the gap. It is pushed down into the pump chamber and is pushed up to the horizontal opening 14 and discharged during discharge.

  Therefore, the liquid and bubbles staying in the bellows can be reliably and quickly discharged out of the pump chamber, and the resist solution deteriorated by the stay clogs the discharge port 8 or the like, or the residual bubbles suddenly discharges the discharge port 8. It is possible to prevent the occurrence of resist failure by exiting from. In addition, when the adjustment operation is performed at the start of use of the apparatus, the resist solution and the bubbles in the pump chamber can be quickly discharged, so that the apparatus adjustment time can be shortened.

  Further, a vertical opening 15 is formed at the tip of the cylindrical protrusion 13, and a fresh resist solution is sucked from the vertical opening 15 when the resist solution is sucked. The resist solution passes through the gap between the projecting portion 13 and the bellows portion, and the resist solution and bubbles that have stayed in the bellows portion can be drawn with this relatively fresh resist solution and pushed out from the horizontal opening 14 to the outside of the pump chamber. .

  Further, as described above, in order to prevent deformation of the bellows portion formed of a resin material such as fluororesin due to pressurization with the resist solution in the pump chamber 6 when the resist solution is discharged, Although the bellows protective member 30 fitted to the outer concave portion 3a is provided, a negative pressure is generated in the pump chamber 6 when the resist solution is sucked, and this negative pressure causes the outer convex portion of the bellows portion. 3b may be deformed, and the bellows protection member 30 cannot prevent this deformation. However, since the flow rate into the pump chamber 6 at the time of inhaling the resist solution can be increased by providing the vertical opening 15, the deformation of the outer convex portion 3 b of the bellows portion is suppressed, the residual deformation or breakage of the bellows portion, etc. Can be prevented.

  FIG. 5 is a cross-sectional view of a bellows pump according to another embodiment of the present invention. In the embodiment described above, the vertical opening 15 is provided at the tip of the columnar protrusion 13, but in this embodiment, only the horizontal opening 14 is provided in the protrusion 13. Even in such a configuration, the liquid and bubbles staying inside the bellows portion are drawn by the flow of the resist solution passing through the gap formed between the protruding portion 13 and the bellows portion of the bellows 3. During inhalation, it is pushed down into the pump chamber 6, and during discharge, it is pushed up to the horizontal opening 14 and discharged. Therefore, the resist solution and bubbles staying in the bellows part can be reliably and rapidly discharged out of the pump chamber. In the case where deformation of the bellows portion due to the negative pressure in the pump chamber 6 does not cause a problem at the time of resist solution inhalation, the bellows pump 1 of this embodiment can be used.

  6 is a cross-sectional view of a bellows pump according to another embodiment of the present invention, FIG. 7 is a state when the bellows pump of FIG. 6 is inhaled with a resist solution, and FIG. 8 is a state when the bellows pump of FIG. .

  In the present embodiment, a check valve 25 is provided in the flow path of the resist solution formed from the vertical opening 15 to the inside of the protruding portion 13. The check valve 25 opens the flow path when the bellows 3 is driven to extend to allow the resist solution to flow into the pump chamber 6 from the vertical opening 15, and flows when the bellows 3 is driven to contract. Is closed to prevent the resist solution from flowing out of the pump chamber 6 from the vertical opening 15.

  Therefore, the flow path from the vertical opening 15 is opened when the resist solution is inhaled, and fresh liquid flows into the pump chamber 6 from the vertical opening 15, while the check valve 25 causes the check valve 25 to discharge from the vertical opening 15 when the resist solution is discharged. This flow path is closed, and the outflow of the resist solution from the vertical opening 15 to the outside of the pump chamber 6 is prevented. Therefore, when the resist solution is discharged, all of the resist solution sucked into the pump chamber 6 containing the fresh resist solution from the vertical opening 15 passes through the gap between the protruding portion 13 and the bellows portion of the bellows 3 and opens horizontally. 14 flows out of the pump chamber 6, and at this time, the resist solution and bubbles staying in the bellows portion are drawn and pushed out of the pump chamber 6 from the horizontal opening 14.

  In this way, a fresh resist solution flows into the pump chamber 6 at the time of inhalation, and all resist solutions in the pump chamber 6 are pushed out of the pump chamber 6 from the horizontal opening 14 by using this fresh resist solution at the time of discharge. Therefore, the liquid and air bubbles staying in the bellows part can be surely and rapidly discharged out of the pump chamber.

  FIG. 11 shows an example of the configuration of a resist coating apparatus by a spinless method using the bellows pump of FIG. The resist coating apparatus 60 includes a resist solution storage unit 47, a discharge nozzle 51, and a bellows pump 1 that sucks the resist solution from the resist solution storage unit 47 and pushes it toward the discharge nozzle 51.

The resist solution reservoir 47 and the bellows pump 1 are communicated by a suction pipe 50, and the bellows pump 1 and the discharge nozzle 51 are communicated by a supply pipe 48. In the bellows pump 1, a suction port 7 that communicates with the pump chamber 6 via the suction-side check valve 11 is connected to the terminal end of the suction pipe 50 and communicates with the pump chamber 6 via the discharge-side check valve 12. The discharge port 8 is connected to the starting end of the supply pipe 48 . In the middle of the supply pipe 48, a filter 63 and an on-off valve 67 for removing bubbles and the like are provided.

  The bellows pump 1 has an electric motor 61 that expands and contracts the bellows 3 in the axial direction via a ball screw mechanism in an expansion / contraction drive unit that expands and contracts the bellows 3. The electric motor 61 is composed of, for example, a pulse motor, and the control unit 64 controls the rotation (rotation direction, rotation amount, rotation speed, etc.) of the electric motor 61, thereby controlling the suction / discharge operation of the bellows pump 1. Reference numeral 62 denotes a rotary encoder for the control unit 64 to confirm the rotation operation of the electric motor 61.

  The discharge nozzle 51 discharges the resist solution onto the substrate 49 while being scanned in the X and Y directions above the substrate by the nozzle scanning mechanism 66. The discharge nozzle 51 is provided with a pressure sensor 65 for detecting the discharge pressure of the resist solution, and predetermined control is performed based on the measured pressure. The nozzle scanning mechanism 66, the pressure sensor 65, and the on-off valve 67 are each connected to a control unit 64 formed of a microcomputer, and the control unit 64 performs predetermined control such as nozzle scanning.

  Although the bellows pump and the resist coating apparatus of each embodiment have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the effects of the present invention. For example, the number and opening positions of the horizontal openings in the protrusion, the mechanism for extending and retracting the bellows, and the like can be selected as appropriate. Of course, the bellows pump of the present invention can be used for applications other than resist coating.

FIG. 1 is a cross-sectional view of a bellows pump according to an embodiment of the present invention. 2 is a cross-sectional view of the bellows pump of FIG. 1 taken along the line AA. FIG. 3 is a view showing a state of the bellows pump shown in FIG. 4 is a view showing a state of the bellows pump of FIG. 1 when discharging the resist solution. FIG. 5 is a cross-sectional view of a bellows pump according to another embodiment of the present invention. FIG. 6 is a cross-sectional view of a bellows pump according to another embodiment of the present invention. FIG. 7 is a view showing a state of the bellows pump of FIG. FIG. 8 is a view showing a state of the bellows pump of FIG. 6 when discharging the resist solution. FIG. 9A is a top view showing the bellows protection member of the bellows pump of FIG. 1, and FIG. 9B is a diagram showing the configuration of the bellows protection member. 10 is an enlarged cross-sectional view taken along line AA of the bellows protective member of FIG. FIG. 11 is a diagram illustrating an example of the configuration of a resist coating apparatus using the bellows pump of FIG. FIG. 12 is a view for explaining a resist coating apparatus using a conventional bellows pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bellows pump 2 Pump head 3 Bellows 3a Outer recessed part 3b Outer convex part 4 Fixed end 5 Movable end 6 Pump chamber 7 Suction port 8 Suction port 9 Suction side joint 10 Suction side joint 11 Suction side check valve 12 Suction side check valve 13 Projection 14 Horizontal Opening 15 Vertical Opening 16 Bellows Presser Plate 17 O-Ring 18 Support Member 19 Fixing Plate 20 Bellows Adapter 21 Ball Screw 22 Bearing 25 Check Valve 30 Bellows Protection Member 31 End 32a Flange Formation Member 32b Flange Formation Member 33 Fixation Metal fitting 34 Screw hole 38 Screw 45 Nut 46 Nut 47 Resist liquid storage tank 48 Supply pipe 49 Substrate 50 Suction pipe 51 Discharge nozzle 60 Resist coating device 61 Electric motor 62 Rotary encoder 63 Filter 64 Control part 65 Pressure sensor 66 Nozzle scanning mechanism 67 Opening and closing valve

Claims (5)

A pump head provided with a suction port for sucking liquid and a discharge port for discharging the liquid;
A telescopic bellows attached to the pump head;
The pump chamber communicated with the suction port and the discharge port, and defined by the bellows,
A bellows pump that sucks and discharges the liquid through the suction port and the discharge port by driving the bellows in a telescopic axis direction,
The pump head is provided with a protrusion that extends toward the pump chamber of the bellows,
In the vicinity of the fixed end of the bellows, a horizontal opening of the protrusion is provided,
The opening end of the horizontal opening is formed so as to open facing the bellows at a position that coincides with the bottom surface of the pump chamber on the pump head side.
When the bellows is driven to extend, the liquid flows into the pump chamber in a direction substantially perpendicular to the direction of the bellows expansion and contraction, and when the bellows is driven to contract, the liquid is bellows outside the pump chamber. A bellows pump configured to flow out in a direction substantially perpendicular to the direction of the telescopic axis. 2. The bellows pump according to claim 1 , wherein the protruding portion has a cylindrical shape, and a plurality of the horizontal openings are formed on a side peripheral portion of the protruding portion. When the bellows is extended and driven, a vertical opening is formed in the tip portion of the projecting portion so that the liquid flows into the pump chamber in a direction substantially parallel to the expansion / contraction axis direction of the bellows. The bellows pump according to claim 1 . When the bellows is extended and driven from the vertical opening to the liquid flow path formed inside the protrusion, the flow path is opened to allow the liquid to flow into the pump chamber from the vertical opening. 4. A check valve is provided that includes a check valve that permits and prevents the outflow of the liquid from the vertical opening to the outside of the pump chamber by closing the flow path when the bellows is contracted. 5 . The bellows pump described. A resist coating apparatus comprising the bellows pump according to claim 1 .

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