JP2019091837A - Liquid supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent liquid from dripping from a nozzle in a liquid supply unit. SOLUTION: A first check valve 50, which is arranged in a first pipe 5 connecting a pump 4 and a tank 3 and stops the flow of liquid from the pump 4 to the tank 3, is connected to a nozzle 2 and the pump 4. A second check valve 60, which is arranged in the second pipe 6 and stops the flow of liquid from the nozzle 2 to the pump 4, is provided, and the second check valve 60 includes an upright tubular room 600 and a room. The room 600 includes a sphere 601 that can move within the 600, and the room 600 has a first room 600a and a first room 600a in which one end side communicates with the nozzle 2 to form a gap between the sphere 601 and the inner wall. It is formed by a columnar second chamber 600b connected to the other end and into which the sphere 601 fits. When the liquid is supplied to the nozzle 2, the sphere 601 floats in the first chamber 600a, and when the liquid supply to the nozzle 2 is stopped. , The sphere 601 is a liquid supply unit that moves downward in the second part 600b due to its own weight and creates a negative pressure in the second pipe 6 path. [Selection diagram] Fig. 2

Description

  The present invention relates to a liquid supply unit that drops liquid on the top surface of a wafer.

  For example, a wafer having devices such as IC and LSI formed in a region partitioned by a planned dividing line on the surface is irradiated with a laser beam of a wavelength having an absorbency to the wafer along the planned dividing line, for example. It is divided into device chips and used for various electronic devices.

  In such a laser processing method, irradiation of a laser beam generates debris in which the wafer is melted. Then, although the debris is sucked by the suction nozzle immediately after generation, all debris can not be sucked. Therefore, before performing laser processing, a water-soluble protective film is formed on the surface of the wafer using a liquid supply unit as shown in Patent Document 1, and adhesion of debris to the wafer surface when laser processing is performed To prevent.

JP, 2015-109304, A

  In the liquid supply unit as disclosed in Patent Document 1, after a predetermined amount of liquid resin is dropped and supplied from the nozzle positioned above the wafer held by the holding table to the center of the wafer, the wafer is rotated at high speed. The liquid resin is drawn over the entire top surface of the wafer by centrifugal force to form a protective film. Here, after the liquid resin is supplied to the wafer, when the nozzle is moved from the center of the wafer to the outside of the wafer, the liquid resin remaining in the vicinity of the supply port of the nozzle may drip on the protective film after formation. There is a problem that the thickness of the protective film becomes uneven due to the dripping.

  Therefore, in the liquid supply unit for forming a protective film, for example, by dripping the liquid on the upper surface of the wafer, there is a problem that the liquid does not drip from the tip of the nozzle on the formed protective film.

  The present invention for solving the above-mentioned problems is a liquid supply unit for dropping a liquid on the upper surface of a wafer, which comprises a nozzle for dropping the liquid on the wafer, a tank for storing the liquid, and an expansion of the chamber from the tank to the nozzle. And a first pump connecting the pump and the tank, and a first pipe connecting the pump and the tank, and stopping the flow of the liquid in the direction from the pump toward the tank. , A second pipe connecting the nozzle and the pump, and a second check valve disposed in the second pipe to stop the flow of liquid from the nozzle toward the pump And the second check valve includes an upright cylindrical chamber and a movable sphere in the chamber, and the chamber communicates one end with the nozzle. A first portion sized to form a gap between the sphere and the inner wall of the room And a cylindrical second chamber connected to the other end of the first chamber and having an inner diameter into which the sphere is fitted, and the pump is supplying liquid to the nozzle. When the sphere floats in the first chamber and the pump stops supplying the liquid to the nozzle, the sphere is inserted into the second chamber by its own weight, and the second chamber is in the second chamber. By moving from the top to the bottom to create a negative pressure in the second piping path.

  A liquid supply unit according to the present invention comprises a first pipe connecting a pump and a tank, and a first check valve disposed in the first pipe and stopping the flow of liquid in a direction from the pump to the tank. A second check valve comprising: a second pipe connecting the nozzle and the pump; and a second check valve disposed in the second pipe to stop the flow of liquid from the nozzle toward the pump Has a cylindrical room set up upright and a sphere movable in the room, and the room has a size such that a gap is formed between the sphere and the inner wall of the room with one end communicating with the nozzle And the second chamber, which is connected to the other end of the first chamber and has a cylindrical second chamber provided with an inner diameter into which the ball is fitted, so that the pump supplies liquid to the nozzle. When so, the sphere floats in the first chamber and the pump stops supplying liquid to the nozzle When doing so, the sphere is inserted into the second chamber by its own weight, and by moving from the top of the second chamber to the bottom, negative pressure is generated in the second piping path and unnecessary liquid drips from the nozzle It became possible to prevent dripping. Therefore, it is not necessary to provide the liquid supply unit with a complicated and expensive anti-drip mechanism.

It is a perspective view which shows an example of the structure of a liquid supply unit. It is sectional drawing which shows an example of the structure of a liquid supply unit. It is sectional drawing which shows the state which supplies a liquid to a nozzle by a pump, makes a liquid drip on the upper surface of a wafer, and forms a protective film. When the pump stops supplying liquid to the nozzle, the ball is inserted into the second chamber by its own weight and descends, thereby providing a negative pressure in the second piping path to prevent dripping from the nozzle. It is sectional drawing which shows the state which is.

  The liquid supply unit 1 according to the present invention shown in FIG. 1 includes, for example, a housing 10 for accommodating the components of the liquid supply unit 1, a holding table 11 for sucking and holding the wafer W, and dripping liquid on the upper surface Wa A nozzle 3 for storing the liquid, a pump 4 for transferring the liquid by expanding and shrinking the chamber 40 from the tank 3 to the nozzle 2, a first pipe 5 for connecting the pump 4 and the tank 3, A first check valve 50 disposed in the pipe 5 of 1 and stopping the flow of liquid in the direction from the pump 4 to the tank 3, a second pipe 6 connecting the nozzle 2 and the pump 4, and a second A second check valve 60 disposed in the pipe 6 and stopping the flow of the liquid in the direction from the nozzle 2 toward the pump 4 is provided. The liquid supply unit 1 can be used alone or can be used by being incorporated into a laser processing apparatus or the like.

  The wafer W shown in FIG. 1 is, for example, a circular semiconductor wafer having silicon or the like as a base material, and a plurality of dividing lines S are set to be orthogonally different on the upper surface Wa of the wafer W Devices D are respectively formed in lattice-like regions partitioned by the planned line S. A protective tape T having a diameter larger than that of the wafer W is attached to the lower surface Wb of the wafer W. The outer periphery of the adhesive surface of the protective tape T is attached to an annular frame F provided with a circular opening, and the wafer W is supported by the annular frame F via the protective tape T.

  The housing 10 is provided with a table accommodating portion 100 provided with a circular opening at the top, and the holding table 11 is disposed in the table accommodating portion 100. In FIG. 1, a part of the side wall of the housing 10 is cut away so that the inside can be grasped.

  The holding table 11 shown in FIG. 1 has, for example, an adsorbing portion 110 which has a circular outer shape and is made of a porous member or the like and adsorbs the wafer W, and a frame 111 supporting the adsorbing portion 110. The suction unit 110 is in communication with a suction source (not shown), and a suction force generated by suction by the suction source is an exposed surface of the suction unit 110 and is formed on a horizontal holding surface 110 a flush with the frame 111. By being transmitted, the holding table 11 sucks and holds the wafer W on the holding surface 110 a.

  Below the holding table 11, a rotating means 113 for rotating the holding table 11 about an axis in the Z-axis direction is disposed. Further, on the outer peripheral portion of the holding table 11, four fixed clamps 112 for fixing the annular frame F are uniformly disposed in the circumferential direction.

  The nozzle 2 is, for example, erected from the bottom of the table housing portion 100, and its outer shape is substantially L-shaped in side view. The supply port 20 formed at the tip of the nozzle 2 opens toward the holding surface 110 a of the holding table 11. The other end 6 b of the second pipe 6 is connected to the root side of the nozzle 2. One end 6 a of the second pipe 6 communicates with the chamber 40 of the pump 4. The nozzle 2 is rotatable around an axis in the Z-axis direction, and can move the supply port 20 from the upper side of the holding table 11 to the retracted position.

  The tank 3 is installed, for example, below the inside of the housing 10, and for example, a supply port 30 for supplying liquid is formed on the side surface thereof. The supply port 30 is connected to one end 5 a of the first pipe 5. The liquid stored in the tank 3 is, for example, a protective film-forming material made of a water-soluble resin (polyvinyl pyrrolidone or polyvinyl alcohol), and an example is HogoMax manufactured by Disco Corporation.

The pump 4 is connected to the other end 5 b of the first pipe 5. In the example shown in FIGS. 1 and 2, the pump 4 is a cylinder pump, and has a cylindrical cylinder 42 having a piston 41 therein, and a piston rod 43 inserted in the cylinder 42 and having one end attached to the piston 41 (see FIG. 2). The piston rod 43 can be moved in the Y-axis direction by applying a force from a moving means or an operator (not shown). The piston 41 moves in the + Y direction and the chamber 40 is expanded, so that liquid can be sucked from the tank 3 via the first pipe 5, and the piston 41 moves in the −Y direction and the chamber 40 is contracted. The liquid can be supplied from the pump 4 to the nozzle 2 through the second pipe 6.
The pump 4 may be, for example, a bellows pump in which a bellows is formed in a tubular shape. In this case, by contracting and expanding the bellows pump, suction force for suctioning the liquid from the tank 3 to the first pipe 5 can be generated.

  As shown in FIG. 2, the first check valve 50 disposed in the first pipe 5 made of SUS, resin or the like has, for example, a valve body movable having an inner diameter larger than the inner diameter of the first pipe 5 A chamber 500 and a spherical ball valve body 501 disposed in the valve body movable chamber 500 are provided. The valve body movable chamber 500 is provided with a reverse conical seating surface 500c in which the inner diameter is reduced to a diameter equal to or less than the diameter of the ball valve body 501 toward the tank 3 side direction and the ball valve body 501 is seated at valve closing. When the liquid is sucked from the tank 3 through the first pipe 5 by the pump 4, the ball valve body 501 is opened (the valve body floats in the movable chamber 500). When the liquid is pushed out from the chamber 40 of the pump 4, the ball valve body 501 closes (seats on the seating surface 500c).

The second check valve 60 includes a standing cylindrical chamber 600 and a spherical body 601 movable in the chamber 600. In the room 600, one end side (upper end side) is communicated with the nozzle 2 so that a gap is formed between the sphere 601 and the inner wall, and the other end of the first room 600a. A cylindrical second chamber 600b is provided, which is connected to the lower end side and has an inner diameter (inner diameter slightly larger than that of the sphere 601) into which the sphere 601 is fitted.
The portion of the room 600 that moves from the first room 600a to the second room 600b is an inverted conical tapered surface. The second chamber 600b is provided with a reverse pyramidal seating surface 600c in which the inner diameter is reduced to a diameter equal to or less than the diameter of the sphere 601 as it goes to the tank 3 side direction and the sphere 601 is seated at valve closing. The sphere 601 is made of, for example, a metal having a higher specific gravity than the liquid stored in the tank 3.

The case where a protective film is formed on the upper surface Wa of the wafer W using the liquid supply unit 1 will be described below.
First, as shown in FIG. 2, the wafer W is transferred onto the holding table 11 and placed on the holding surface 110 a so that, for example, the upper surface Wa is on the upper side. Then, the suction force generated by a suction source (not shown) is transmitted to the holding surface 110a, whereby the holding table 11 suctions and holds the wafer W on the holding surface 110a. Further, the annular frame F is clamped and fixed by the fixing clamp 112.

The nozzle 2 is pivoted, and the supply port 20 is positioned above the center of the top surface Wa of the wafer W. As the piston 41 moves in the + Y direction and the chamber 40 is expanded, liquid is drawn from the tank 3 via the first pipe 5, and the ball valve body 501 of the first check valve 50 is the pump 4. It is opened by floating in the valve body movable chamber 500 by the liquid flowing toward the side, and the liquid flows into the chamber 40 of the pump 4. On the other hand, the second check valve 60 is in a closed state because the ball 601 is seated on the seating surface 600c of the second chamber 600b by its own weight.
For example, when the piston 41 moves to the end on the + Y direction side of the cylinder 42 and stops, the liquid is sufficiently accumulated in the chamber 40. In addition, since the flow of the liquid toward the pump 4 side in the first piping 5 path is lost, the ball valve body 501 of the first check valve 50 is lowered by its own weight and is seated on the seating surface 500c. The non-return valve 50 is closed.

  As shown in FIG. 3, when the piston 41 moves in the −Y direction and the chamber 40 is contracted, the liquid flows from the pump 4 into the second pipe 6, and the second check valve 60 has a ball 601 as a nozzle It is opened by floating in the first chamber 600 a by the liquid flowing toward the 2 side, and the liquid flows into the nozzle 2. Here, in the first chamber 600a, since a gap of a predetermined size is formed between the inner wall and the sphere 601, the floating of the sphere 601 is not blocked by the inner wall of the first chamber 600a. The flow of the liquid toward the nozzle 2 side in the second piping 6 path also becomes smooth. On the other hand, the flow of liquid in the first piping 5 path is stopped by the first check valve 50 in the closed state. Then, while the liquid is dropped from the supply port 20 of the nozzle 2 to a substantially central portion of the upper surface Wa of the wafer W suctioned and held on the holding table 11, the holding table 11 rotates at a predetermined rotation speed.

  The dropped liquid spreads from the center side to the outer peripheral side of the upper surface Wa of the wafer W by centrifugal force, and the liquid is applied to substantially the entire upper surface Wa. That is, as shown in FIG. 3, a protective film J having a substantially uniform predetermined thickness is formed on the upper surface Wa of the wafer W.

  For example, when the piston 41 moves to the end on the −Y direction side of the cylinder 42 and stops, most of the liquid is discharged from the chamber 40 of the pump 4 and the supply of liquid from the pump 4 to the nozzle 2 is stopped. Ru. Further, since the flow of the liquid toward the nozzle 2 side in the second piping 6 path is lost, as shown in FIG. 4, the sphere 601 of the second check valve 60 is in the first chamber 600 a by its own weight. Going down. Also, the force applied to the piston rod 43 to release the piston 41 in the -Y direction is released.

The portion of the chamber 600 which moves from the first chamber 600a to the second chamber 600b is an inverted pyramidal tapered surface, so that the sphere 601 which is lowered by its own weight is guided by the tapered surface, and the second chamber It is inserted into 600b. For example, the liquid may remain in the vicinity of the inside of the supply port 20 of the nozzle 2, but the sphere 601 inserted into the second chamber 600b is further lowered by its own weight in the section L shown in FIG. As a result, the inside of the second piping 6 path becomes negative pressure, and the atmospheric pressure from the supply port 20 of the nozzle 2 pushes the inside of the second piping 6 path and returns the liquid to the chamber 600. That is, the remaining liquid is supplied from the supply port 20 of the nozzle 2 due to the negative pressure generated by falling down in the section L by its own weight before the sphere 601 is fitted into the second chamber 600 b and seated on the seating surface 600 c. From near the inside, it is pulled in toward the pump 4 and retreats (sucks back). The volume of the liquid that can be sucked back is the product of the cross-sectional area of the second chamber 600b and the section L. Then, the spherical body 601 is seated on the seating surface 600c of the second chamber 600b, so that the state of being pushed to the atmospheric pressure is maintained, and the pump 4 in a state where liquid dripping from the inside of the supply port 20 is effectively suppressed. Enables the suction of liquid from the tank 3. In addition, since the force applied to the piston rod 43 is released, the second pipe 6 on the pump 4 side of the second chamber 600b as the ball 601 descends in the section L by its own weight. Due to the pressure in the path, the piston 41 is also pushed in the + Y direction and driven to expand the chamber 40.
In the above, the chamber 40 is expanded when it is inserted into the second chamber 600b by the weight of the sphere 601, but in order to lock the first check valve 50 so as not to open, the second chamber 600b After the sphere 601 is inserted by its own weight, the piston 41 is operated in the + Y direction to lower the sphere 601 in the section L in the pipe area from the second chamber 600b in the second pipe 6 path to the pump 4 It is possible to generate a negative pressure to lower the sphere 601 in the section L by the negative pressure. In this case, the operation for the pump 4 to suck the liquid to be supplied to the next wafer W forming the protective film from the tank 3 and store it in the chamber 40 is directly from the supply port 20 of the nozzle 2. It interlocks to help the downward movement of the sphere 601 to prevent the liquid from dripping.

After the supply of the liquid from the nozzle 2 is stopped, the rotation of the holding table 11 is further continued to rotate and dry the protective film J. It should be noted that the protective film J of a desired thickness is not formed on the upper surface Wa of the wafer W by supplying the liquid once but by repeating the application and drying of a small amount of liquid a plurality of times. It is good also as what is formed in the upper surface Wa of.
Thereafter, in order to carry out the wafer W from the holding table 11, the nozzle 2 turns to move the supply port 20 from the upper side of the holding table 11 to the retracted position. Here, since the liquid is sucked back from the inside of the supply port 20 of the nozzle 2 as described above, the unnecessary liquid protects the upper surface Wa of the wafer W from the nozzle 2 due to the vibration applied to the nozzle 2 along with the turning. It is possible to prevent the occurrence of liquid dripping on the membrane J.

  As described above, the liquid supply unit 1 according to the present invention includes the first pipe 5 connecting the pump 4 and the tank 3 and the liquid in the direction from the pump 4 toward the tank 3 disposed in the first pipe 5. The second check valve 50 for stopping the flow of the fluid, the second pipe 6 connecting the nozzle 2 and the pump 4, and the flow of the liquid in the direction from the nozzle 2 toward the pump 4 And the second check valve 60 includes a standing cylindrical chamber 600 and a ball 601 movable in the chamber 600. A first chamber 600a of a size such that a gap is formed between the ball 601 and the inner wall of the room, and one end of the first chamber 600a communicating with the nozzle 2 and the other end of the first chamber 600a are connected And a cylindrical second chamber 600b having an inner diameter into which the When the liquid is supplied to the nozzle 2 by the pump 4, the sphere 601 floats in the first chamber 600a, and when the pump 4 stops supplying the liquid to the nozzle 2, the sphere 601 has its own weight. The liquid is dripped into the second chamber 600b by moving the second chamber 600b downward from above to make the inside of the second pipe 6 path negative pressure so that unnecessary liquid drips from the nozzle 2 Came to be able to prevent. Therefore, it is not necessary to provide the liquid supply unit 1 with a complicated and expensive liquid drip prevention mechanism.

  The liquid supply unit 1 according to the present invention is not limited to the form described above, and the size, shape, etc. of each component illustrated in the accompanying drawings are not limited to this, and the present invention is not limited thereto. It can change suitably in the range which can exhibit the effect of invention.

1: Liquid supply unit 10: Housing 100: Table accommodating part 11: Holding table 110: Adsorption part 110a: Holding surface 111: Frame 112: Fixed clamp 113: Rotation means
2: Nozzle 20: Supply port 3: Tank 30: Supply port 4: Pump 40: Chamber 41: Piston 42: Cylinder 43: Piston rod
5: first piping 50: first check valve 500: valve body movable chamber 500c: seating surface 501: ball valve body 6: second piping 60: second check valve 600: tubular chamber 600a : First chamber 600b: Second chamber 601: Sphere W: Wafer F: Annular frame T: Protective tape

Claims (1)

A liquid supply unit for dropping liquid on the upper surface of a wafer, comprising:
A nozzle for dropping a liquid onto a wafer, a tank for storing the liquid, and a pump for transferring the liquid from the tank to the nozzle by expanding and contracting the chamber;
A first pipe connecting the pump and the tank; a first check valve disposed in the first pipe to stop the flow of liquid from the pump toward the tank; the nozzle and the nozzle A second pipe connecting the pump, and a second check valve disposed in the second pipe and stopping a flow of liquid in a direction from the nozzle toward the pump;
The second check valve includes a standing cylindrical chamber and a sphere movable in the chamber,
The chamber is connected to a first chamber sized to communicate one end side with the nozzle and to form a gap between the sphere and the inner wall of the chamber, and to the other end of the first chamber. And a second cylindrical chamber having an inside diameter into which the spheres fit;
When the pump is supplying liquid to the nozzle, the sphere floats in the first chamber, and when the pump stops supplying liquid to the nozzle, the sphere is under its own weight. A liquid supply unit which is inserted into the second chamber and moves down in the second chamber to make the inside of the second piping path negative pressure.

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