JP2021084081A - Dripping prevention mechanism and coating applicator - Google Patents

Abstract

To provide a dripping prevention mechanism capable of preventing coating liquid from dripping from a nozzle tip; and to provide a coating applicator.SOLUTION: A dripping prevention mechanism 10 used for a nozzle 20 for supplying coating liquid to a medium 12 to be coated, includes a dripping prevention part 31 provided on a part of a coating liquid supply pipe 22 communicating with the nozzle 20, which is the dripping prevention part 31 having a volume variable chamber constituting a part of the inner space of the coating liquid supply pipe 22, and having a variable volume, and a control part 50 for preventing dripping from the nozzle 20 by enlarging the volume of the volume variable chamber, when the nozzle 20 stops supply of the coating liquid.SELECTED DRAWING: Figure 1

Description

The present invention relates to a dripping prevention mechanism and a coating device for preventing dripping of a nozzle that supplies a coating liquid to the surface of a wafer.

In the manufacture of semiconductors, wafers are processed while various films are formed on the surface of the wafer. For example, a resist film is formed on the surface of the wafer during exposure, and a protective film that protects the device layer is formed during grooving (grooving). Various coating devices are provided for forming these films. When forming the film, various coating liquids are supplied to the wafer surface from the nozzle of the coating device, and the film is formed by a process such as drying the coating liquid.

After the coating liquid is supplied from this nozzle, the coating liquid remaining in the pipe of the nozzle may drip (drips) from the ejection port of the nozzle onto the wafer, so-called dripping. Since this dripping causes problems such as making the thickness of the film uneven, it is necessary to prevent this dripping.

For example, Patent Documents 1 and 2 disclose a configuration in which a check valve is provided on a pipe that supplies a coating liquid to a nozzle. This check valve has an internal space communicating with the coating liquid supply path and a sphere provided in the internal space. When the coating liquid is supplied from the nozzle, the sphere floats in the coating liquid in the internal space. When the supply of the coating liquid is stopped, the sphere moves to the lower end of the internal space to prevent the supply of the coating liquid to the tip of the nozzle, thereby preventing dripping.

JP-A-2019-091837 Japanese Unexamined Patent Publication No. 2019-0966662

However, the techniques described in Patent Documents 1 and 2 have a problem that the dripping of the coating liquid remaining at the tip of the nozzle cannot be effectively prevented.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a mechanism capable of preventing dripping more effectively.

In order to achieve the above object, the dripping prevention mechanism used for the nozzle for supplying the coating liquid to the medium to be coated according to the present disclosure is a dripping prevention unit provided in a part of the coating liquid supply pipe communicating with the nozzle. The volume of the liquid dripping prevention portion, which constitutes a part of the internal space of the coating liquid supply pipe and has a variable volume chamber, and the volume of the variable volume chamber when the nozzle stops supplying the coating liquid. It is provided with a control unit that prevents dripping from the nozzle by enlarging.

Preferably, when the supply of the coating liquid to the medium to be coated is stopped, the control unit expands the volume of the variable volume chamber by extending the coating liquid supply pipe in the longitudinal axis direction of the coating liquid supply pipe. When the supply of the coating liquid from the nozzle is stopped, the coating liquid remaining in the nozzle protrudes from the tip of the nozzle (nozzle opening) and forms a curved surface that is convex downward in the vertical direction due to surface tension. In this case, if the volume of the variable volume chamber is increased, the volume of the entire coating liquid supply pipe increases, so that the coating liquid at the tip of the nozzle is drawn into the nozzle. As a result, dripping of the coating liquid remaining at the tip of the nozzle is suppressed.

The change in the volume of the variable volume chamber may be linked to the vertical movement of the nozzle by the nozzle drive unit. As a result, the dripping prevention mechanism can be automatically activated according to the operation of the nozzle.

Preferably, in the above-mentioned dripping prevention mechanism, the upper part of the variable volume chamber is connected to the nozzle drive unit and can move up and down, the lower part of the variable volume chamber is immovable, and the length of the variable volume chamber is the length of the nozzle drive unit. It can be expanded and contracted in conjunction with vertical movement.

Preferably, the coating liquid supply pipe includes a vertical supply pipe provided in parallel in the vertical direction, and the dripping prevention portion is provided on the vertical supply pipe.

Preferably, the dripping prevention unit includes any of a bellows, a nesting tube, and an elastic tube as a part of the coating liquid supply tube. In this case, the variable volume chamber is formed inside any of the bellows, nested tubes, and elastic tubes.

Further, preferably, the above-mentioned dripping prevention mechanism further includes a drying prevention tank for storing the drying prevention liquid for preventing the nozzle from drying. When the nozzle is not used, the tip of the nozzle can be immersed in the anti-drying liquid to prevent the tip of the nozzle from drying.

Preferably, the control unit measures the volume of the variable volume chamber so that the volume of the variable volume chamber when the nozzle is immersed in the antidrying liquid is smaller than the volume of the variable volume chamber when the nozzle is prevented from dripping. To change. As a result, the tip of the nozzle can be immersed in the anti-drying liquid without air bubbles in the nozzle, so that the tip of the nozzle can be effectively prevented from drying.

Further, preferably, the above-mentioned dripping prevention mechanism is applied to the coating device.

According to the present invention, it is possible to effectively prevent the coating liquid remaining at the tip of the nozzle from dripping after the supply of the coating liquid is stopped.

Schematic configuration of a coating device equipped with a dripping prevention mechanism Schematic configuration of the coating liquid supply path and the vicinity of the nozzle Functional block diagram of the control unit The figure explaining the operation of the nozzle The figure explaining the operation of the dripping prevention mechanism The figure which shows the deformation example of the dripping prevention part The figure which shows the deformation example of the dripping prevention part

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, as an example, the coating device is a rotary coating device and the coated medium (work) is a wafer, but it is not intended to limit the coating device and the coated medium.

<Embodiment>
First, the configuration of the coating device provided with the dripping prevention mechanism will be described with reference to FIG. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other, the X-axis direction is the horizontal direction, the Y-axis direction is the horizontal direction orthogonal to the X-axis direction, and the Z-axis direction is the vertical direction (vertical). Direction). The coating device 100 shown in FIG. 1 includes a table 10, a nozzle 20, a dripping prevention mechanism 30, a table rotating device 40, a control unit 50, and a shield (coating pot) 60.

The table 10 is parallel in the horizontal direction, and the wafer 12 is sucked and held by using a suction device (not shown). For example, the wafer 12 is placed on the table 10 so that the center of the flat plate-shaped wafer 12 substantially coincides with the center of the table 10. Alternatively, the wafer 12 may be placed on the table 10 in a state of being fixed to the frame (not shown) via a dicing tape (not shown).

The nozzle 20 supplies the coating liquid for forming the film to the wafer 12. The coating liquid is appropriately selected according to the type of film to be formed. The diameter of the nozzle 20 is, for example, 6 mm to 8 mm.

The dripping prevention mechanism 30 prevents the coating liquid from dripping from the nozzle opening 21 at the tip of the nozzle 20 onto the wafer 12 when the supply of the coating liquid is stopped. The dripping prevention mechanism 30 includes a dripping prevention unit 31 and a nozzle driving unit 36. The nozzle drive unit 36 rotates the nozzle 20 around a rotation axis parallel to the Z axis, and moves the nozzle 20 in the Z axis direction (up and down movement). The nozzle drive unit 36 includes a rotary motor (not shown), a linear actuator, a position sensor for detecting the movement amount and the rotation amount of the nozzle, and the like. Examples of the position sensor include an encoder. From the detection result of the position sensor, the relative positions (relative distances) between the nozzle 20 and the table 10 in the X, Y, and Z axis directions can be obtained. Since the configuration of the nozzle drive unit 36 is known, detailed description thereof will be omitted. Details of the configuration and operation of the dripping prevention mechanism 30 will be described later.

The table rotating device 40 uses a motor (not shown) to rotate the table 10 around a rotating axis (parallel to the Z axis) that passes through the center of the table 10 and is perpendicular to the surface of the table 10. The control unit 50 controls the flow rate of the coating liquid, the dripping prevention mechanism 30 (nozzle drive unit 36), and the table rotating device 40. The control unit 50 will be described in detail later.

The shield 60 is erected around the table 10. The shield 60 shields the coating liquid scattered from the surface of the wafer 12 during the rotary coating, and prevents other devices of the coating apparatus 100 from being contaminated with the coating liquid. The shield 60 may not be required depending on the viscosity of the coating liquid and the type of the coating device 100.

FIG. 2 is a schematic configuration diagram of a coating liquid supply path and the vicinity of the nozzle 20. The nozzle 20 is connected to the coating liquid tank 23 via the coating liquid supply pipe 22 and other pipes. The coating liquid supply pipe 22 is erected in parallel with the Z axis (longitudinal axis direction). The coating liquid supply pipe 22 has, for example, a horizontal supply pipe 26 substantially parallel to the XY plane and a vertical supply pipe 27 substantially parallel to the Z axis. The tip of the horizontal supply pipe 26 communicates with the nozzle 20, and the base end of the horizontal supply pipe 26 communicates with the vertical supply pipe 27. The central axis of the vertical supply pipe 27 coincides with the rotation axis of the nozzle 20. The dripping prevention portion 31 is provided on the vertical supply pipe 27 in parallel with the Z-axis direction. The dripping prevention unit 31 has, for example, a bellows (variable volume chamber) 32 that can expand and contract in the Z-axis direction. The diameter of the bellows 32 is substantially the same as that of the nozzle 20, for example, 6 mm to 8 mm in diameter. The length of the bellows 32 in the Z-axis direction is, for example, 30 mm to 40 mm.

On the base end side of the vertical supply pipe 27, the pump 25 and the check valve (or control valve) are sequentially provided from the downstream side (nozzle 20 side) to the upstream side (coating liquid tank 23 side) via the pipe. 24 is arranged. FIG. 2 shows a plunger pump as the pump 25. When supplying the coating liquid, the coating liquid supplied from the coating liquid tank 23 via the check valve 24 is sent out to the coating liquid supply pipe 22 by the reciprocating operation of the plunger of the pump 25. When the supply of the coating liquid is stopped, the plunger of the pump 25 is stopped. When the pump 25 is stopped, the check valve 24 operates so as to prevent the coating liquid from flowing back from the coating liquid supply pipe 22 side to the coating liquid tank 23 side. The pump 25 is not limited to the plunger pump. As the pump 25, any pump such as a diaphragm pump, a piston pump, and a rotary pump can be used.

The upper portion of the dripping prevention unit 31 is connected to the arm 34 of the nozzle drive unit 36 and is configured to be vertically movable. The lower portion of the dripping prevention unit 31 is fixed to an arbitrary member such as a housing of the coating device 100 and is immovably configured. Examples of the material of the bellows 32 include metal and resin.

Further, a guide member 33 for preventing the bellows 32 from being significantly bent in the horizontal direction (X-axis and Y-axis directions) may be provided around the bellows 32. Alternatively, a core (not shown) that prevents the bellows 32 from bending significantly in the horizontal direction may be provided in the bellows 32 as a guide member.

Further, a drying prevention tank 35 is provided in the vicinity of the nozzle 20. The anti-drying tank 35 stores an anti-drying liquid that prevents the nozzle from drying. Examples of the anti-drying liquid include the same solution as the coating liquid, water, and the like.

FIG. 3 is a functional block diagram of the control unit 50. The control unit 50 includes, for example, an interface 51, a nozzle drive control unit 52, a flow rate control unit 53, and a table rotation control unit 54. The interface 51 is a means for exchanging commands and data with a user and each device, and is, for example, a keyboard, a mouse, a touch panel, a display, a speaker, a data communication device (network connection device), and the like.

The nozzle drive control unit 52 controls the nozzle drive unit 36 based on a command from the user and data from the position sensor. The flow rate control unit 53 controls the flow rate of the coating liquid supplied to the nozzle 20 by controlling the pump 25 based on a command from the user. The table rotation control unit 54 controls the table rotation device 40. The nozzle drive control unit 52, the flow rate control unit 53, and the table rotation control unit 54 are realized by using, for example, a processor. In FIG. 3, the nozzle drive control unit 52, the flow rate control unit 53, and the table rotation control unit 54 are shown separately according to their functions, but in reality, it can be realized by one processor. Further, the control unit 50 includes a ROM (Read Only Memory) (not shown), a RAM (Random Access Memory) (not shown), and the like. Various programs such as control programs stored in the ROM are expanded in the RAM, and the programs expanded in the RAM are executed by the processor to execute various arithmetic processes and control processes.

Next, the operation of the nozzle 20 will be described with reference to FIG. First, as shown by the solid line in FIG. 4, the nozzle driving unit 36 moves the nozzle 20 so that the nozzle port 21 faces the table 10. At this time, the bellows 32 of the dripping prevention unit 31 is in a contracted state. In this state, the coating liquid is supplied onto the wafer 12 from the nozzle 20.

When the supply of the coating liquid is completed, as shown by the alternate long and short dash line in FIG. 4, the nozzle driving unit 36 raises the nozzle 20 by moving (raising) the arm 34 upward in the Z-axis direction, and is above the shield 60. Moves (retracts) the nozzle 20 to. While the upper part of the dripping prevention part 31 is movably connected to the arm 34, the lower part of the dripping prevention part 31 is immovable, so that the bellows 32 of the dripping prevention part 31 is interlocked with the rise of the arm 34. It will be in an elongated state. Subsequently, the nozzle drive unit 36 rotates the nozzle 20 around the vertical supply pipe 27 (rotation axis) to move the nozzle 20 above the drying prevention tank 35. After that, as shown by the dotted line in FIG. 4, the nozzle driving unit 36 lowers the nozzle 20 by lowering the arm 34, and immerses the nozzle port 21 in the anti-drying liquid stored in the anti-drying tank 35. At this time, the bellows 32 of the dripping prevention portion 31 is in a contracted state in conjunction with the lowering of the arm 34.

Subsequently, the operation of the dripping prevention mechanism 30 when the nozzle 20 operates as shown in FIG. 4 will be described with reference to FIG. In FIG. 5, reference numeral 5A is a schematic cross-sectional view of the nozzle 20 immediately after the supply of the coating liquid is stopped, reference numeral 5B is a schematic cross-sectional view of the nozzle 20 when the dripping prevention portion is extended, and reference numeral 5C is a nozzle. It is the schematic sectional drawing of the nozzle 20 when the mouth 21 is immersed in the anti-drying tank 35. Further, in FIG. 5, diagonal lines indicate the state of the coating liquid.

As shown by reference numeral 5A, when the supply of the coating liquid from the nozzle 20 is stopped, the coating liquid remaining in the nozzle 20 protrudes from the end of the nozzle opening 21 and forms a curved surface that is convex downward in the vertical direction due to surface tension. To do. When the arm 34 is raised from the state indicated by reference numeral 5A, the bellows 32 extends (the volume of the bellows increases) as shown by reference numeral 5B, so that the volume of the entire coating liquid supply pipe 22 increases. That is, the inside of the bellows 32 functions as a variable volume chamber with a variable volume. Since the volume of the entire coating liquid supply pipe 22 increases, the coating liquid protruding from the end of the nozzle opening 21 is drawn into the nozzle 20 and forms a curved surface that is convex upward in the vertical direction due to surface tension. In the state shown by reference numeral 5B, dripping of the coating liquid is suppressed. In the state shown by reference numeral 5B, the nozzle 20 is rotated and moved to the upper part of the drying prevention tank 35.

When the nozzle port 21 is immersed in the anti-drying liquid stored in the anti-drying tank 35, the bellows 32 of the dripping prevention unit 31 is in a contracted state as shown by reference numeral 5C. At this time, it is desirable to lower the nozzle 20 by an amount equal to or greater than the amount of movement in which the nozzle 20 is raised when changing from the state indicated by the reference numeral 5A to the state indicated by the reference numeral 5B. In other words, it is desirable to contract the bellows 32 by a length greater than or equal to the length by which the bellows 32 is extended.

As a result, the volume of the bellows 32 when the nozzle port 21 is immersed in the antidrying liquid becomes equal to or less than the volume of the bellows 32 when the coating liquid is supplied. As a result, the coating liquid drawn into the nozzle 20 protrudes from the end of the nozzle opening 21, so that the nozzle 20 is in a state where there are no air bubbles inside the nozzle 20. Since the nozzle port 21 can be immersed in the anti-drying liquid in the anti-drying tank 35 in the absence of air bubbles, the nozzle port 21 can be effectively prevented from drying. Further, even if the coating liquid drips when immersed in the drying prevention liquid, the coating liquid only drops into the drying prevention tank 35, so that there is no problem that other devices are contaminated by the coating liquid.

In this way, according to the dripping prevention mechanism 30, by increasing or decreasing the volume of the coating liquid supply pipe 22, it is possible to prevent the dripping of the coating liquid remaining at the tip of the nozzle 20 after the supply of the coating liquid is stopped. it can.

Further, since the nozzle drive unit provided in the conventional coating device can also be used (diverted) as the nozzle drive unit 36 of the dripping prevention mechanism 30, the dripping prevention mechanism 30 can be realized at low cost.

<Modification example>
Hereinafter, a modified example of the dripping prevention unit 31 of the dripping prevention mechanism 30 will be described with reference to FIGS. 6 and 7.

In the modified example shown in FIG. 6, the dripping prevention unit 31 includes a telescopic tube 37 instead of the bellows 32. The nested tube 37 has an outer tube 37-1 and an inner tube 37-2. Since the outer diameter of the inner pipe 37-2 is smaller than the inner diameter of the outer pipe 37-1, the inner pipe 37-2 can slide inside the outer pipe 37-1, and the inner pipe 37-2 and the outer pipe 37-1 Is relatively movable in the longitudinal axis direction of the coating liquid supply pipe 22 (vertical supply pipe 27). A seal 38 (for example, an O-ring) forms a liquid-tight structure between the outer tube and the inner tube. When the arm 34 rises from the state indicated by reference numeral 6A in FIG. 6, the nesting tube 37 extends as shown by reference numeral 6B, so that the same effect as that of the dripping prevention portion 31 using the bellows 32 can be obtained. In the case of the modified example shown in FIG. 6, the inside of the nesting tube 37 corresponds to the variable volume chamber.

In the modified example shown in FIG. 7, the dripping prevention portion 31 includes an elastic tube 39 that can be expanded and contracted instead of the bellows 32. The elastic tube 39 can be expanded and contracted in the longitudinal axis direction of the coating liquid supply pipe 22 (vertical supply pipe 27). Examples of the material of the elastic tube 39 include rubber such as silicone. When the arm 34 rises from the state indicated by reference numeral 7A in FIG. 7, the elastic tube 39 extends as shown by reference numeral 7B, so that the same effect as that of the dripping prevention portion 31 using the bellows 32 can be obtained. In the case of the modified example shown in FIG. 7, the inside of the elastic tube 39 corresponds to the variable volume chamber.

<Effect>
As described above, according to the dripping prevention mechanism 30 according to the present disclosure, it is possible to effectively prevent the coating liquid remaining at the tip of the nozzle from dripping after the supply of the coating liquid is stopped.

As a configuration for driving the dripping prevention mechanism 30, the nozzle driving unit provided in the conventional coating device can also be used (diverted), so that the dripping prevention mechanism 30 can be realized at low cost.

Since the nozzle port 21 can be immersed in the anti-drying liquid in the anti-drying tank 35 in a state where there are no air bubbles inside the nozzle 20, the nozzle port 21 can be effectively prevented from drying.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and it goes without saying that various improvements and modifications may be made without departing from the gist of the present invention. ..

10 ... table, 12 ... wafer, 20 ... nozzle, 21 ... nozzle port, 22 ... coating liquid supply pipe, 23 ... coating liquid tank, 24 ... check valve, 25 ... pump, 26 ... horizontal supply pipe, 27 ... vertical supply Tube, 30 ... dripping prevention mechanism, 31 ... dripping prevention part, 32 ... bellows, 33 ... guide member, 34 ... arm, 35 ... drying prevention tank, 36 ... nozzle drive unit, 37 ... nested pipe, 38 ... seal, 39 ... Elastic tube, 40 ... Table rotation device, 50 ... Control unit, 51 ... Interface, 52 ... Nozzle drive control unit, 53 ... Flow control unit, 54 ... Table rotation control unit, 100 ... Coating device

Claims (9)

A dripping prevention mechanism used for a nozzle that supplies a coating liquid to a medium to be coated.
A dripping preventive portion provided in a part of the coating liquid supply pipe communicating with the nozzle, which constitutes a part of the internal space of the coating liquid supply pipe and has a variable volume chamber. Prevention part and
A control unit that prevents dripping from the nozzle by expanding the volume of the volume variable chamber when the nozzle stops supplying the coating liquid.
A dripping prevention mechanism equipped with. When the supply of the coating liquid to the coating medium is stopped, the control unit expands the volume of the volume variable chamber by extending the coating liquid supply pipe in the longitudinal axis direction of the coating liquid supply pipe. ,
The dripping prevention mechanism according to claim 1. The dripping prevention portion is composed of a bellows provided in a part of the coating liquid supply pipe.
The bellows can be expanded and contracted along the longitudinal axis direction of the coating liquid supply pipe.
The variable volume chamber is formed inside the bellows.
The dripping prevention mechanism according to claim 2. A guide member for guiding the expansion / contraction direction of the bellows is provided.
The dripping prevention mechanism according to claim 3. The dripping prevention portion is composed of a nesting pipe provided in a part of the coating liquid supply pipe.
The nested pipe has an inner pipe and an outer pipe, and the inner pipe and the outer pipe are relatively movable in the longitudinal axis direction of the coating liquid supply pipe.
The variable volume chamber is formed inside the nesting tube.
The dripping prevention mechanism according to claim 2. The dripping prevention portion is composed of an elastic tube provided in a part of the coating liquid supply pipe.
The elastic tube can be expanded and contracted along the longitudinal axis direction of the coating liquid supply tube.
The variable volume chamber is formed inside the elastic tube.
The dripping prevention mechanism according to claim 2. A drying prevention tank for storing a drying prevention liquid for preventing the nozzle from drying is further provided.
The dripping prevention mechanism according to any one of claims 1 to 6. The control unit has the volume so that the volume of the volume variable chamber when the nozzle is immersed in the anti-drying liquid is smaller than the volume of the volume variable chamber when the nozzle is prevented from dripping. Change the volume of the variable chamber,
The dripping prevention mechanism according to claim 7. The dripping prevention mechanism according to any one of claims 1 to 8.
A rotary table holding the medium to be coated and
A nozzle that supplies a coating liquid toward the medium to be coated, and
A coating liquid supply pipe that communicates with the nozzle,
With
A part of the coating liquid supply pipe is composed of the dripping prevention portion.
Coating device.

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