JP2010098029A - Drainage mechanism of processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drainage mechanism of processing apparatus, which has a simple configuration and is economical. <P>SOLUTION: The drainage mechanism of a processing apparatus drains a waste liquid sucked from a holding means of the processing apparatus including the holding means for sucking and holding an object to be processed, a processing means for processing the object held by the holding means while supplying processing water to the object, and a suction means for transmitting a suction force to the holding means. The drainage mechanism comprises: a first connection pipe connecting the holding means and the suction means; a first water tank disposed in the first connection pipe; a second connection pipe disposed to be hanged in the first water tank; a second water tank connected to the second connection pipe; a third connection pipe connecting the second water tank and the suction means; a drain disposed to be hanged in the second water tank; a first valve disposed in the second connection pipe; a second valve disposed in the third connection pipe; a third valve disposed in a channel connected to the drain; and an air relief valve disposed above the second water tank. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drainage mechanism of a processing apparatus that processes a workpiece such as a wafer while supplying processing water.

  A semiconductor wafer formed in a region partitioned by lines to be divided in which devices such as ICs and LSIs are formed in a grid pattern is ground by a grinding machine to a predetermined thickness, and then divided by a dicing machine. The device is cut along a predetermined line and divided into individual devices, and the divided devices are used for electric devices such as mobile phones and personal computers.

  When dicing with a dicing machine, the wafer is sucked and held on the chuck table by the negative pressure generated by the vacuum suction source, and the wafer is divided into individual lines by cutting the planned dividing line of the wafer with a cutting blade while supplying cutting water. It is divided into devices.

  There are two methods for adsorbing workpieces on the chuck table: the “tape mount method” in which dicing tape is attached to the back of the wafer, and a chuck table with multiple suction holes formed without using dicing tape. There are two types of “direct placement processing method” in which the workpiece is directly adsorbed and cut, and is used depending on the type of workpiece.

  The tape mount system uses a porous chuck table made of porous ceramics, etc., and adsorbs the entire surface of the dicing tape, so there is no problem even if the suction force is relatively small, and due to the presence of the dicing tape Since there is little risk of cutting water entering the vacuum suction source, an ejector vacuum pump (hereinafter simply referred to as “ejector”) is generally used as the vacuum suction source.

  On the other hand, in the direct placement processing method, a generally hard workpiece such as a ceramic substrate is adsorbed to a direct placement chuck table made of metal such as SUS, so that liquid can enter through the chuck table. A water-sealed vacuum pump is generally used that requires a higher suction force than the tape mount method and does not lower the suction force even when water is sucked as a vacuum suction source.

Japanese Patent Application Laid-Open No. 2008-78424 discloses a vacuum suction source having a strong suction force that does not decrease a suction force even when cutting water is sucked in order to correspond to two types of processing methods, a tape mount method and a direct placement processing method, There has been disclosed a cutting apparatus in which a vacuum suction source used when cutting water is difficult to be sucked by a suction source as in the tape mount method and two vacuum suction sources can be selectively used.
JP 2008-78424 A

  The cutting apparatus disclosed in Patent Document 1 has a problem that the cost of the apparatus increases because two types of vacuum suction sources are arranged and switched as necessary. One vacuum suction source has a problem that the life of the vacuum suction source is shortened although the suction force does not decrease even when cutting water is sucked. Such a problem also occurs in a grinding apparatus that grinds a wafer, and is a common problem in a processing apparatus that uses processing water.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an economical drainage mechanism for a processing apparatus with a simple configuration capable of dealing with both a tape mount method and a direct placement processing method. Is to provide.

  Processing that includes holding means for sucking and holding a workpiece, processing means for performing processing while supplying processing water to the workpiece held by the holding means, and suction means for transmitting a suction force to the holding means A drainage mechanism of a processing apparatus for draining waste liquid sucked from the holding means of the apparatus, the first connecting pipe connecting the holding means and the suction means, and disposed in the middle of the first connecting pipe A first reservoir tank provided; a second connecting pipe that is suspended from the first reservoir tank; a second reservoir tank connected to the second connecting pipe; A third connecting pipe that connects the second water tank and the suction means, a drain that is suspended from the second water tank, and a first pipe that is provided in the second connecting pipe. A valve, a second valve disposed in the third connecting pipe, and a third valve disposed in a conduit connected to the drain. And an air release valve disposed on the upper portion of the second water reservoir tank. The suction means is operated to transmit a suction force to the holding means so that the waste liquid is supplied to the second water reservoir tank. When accumulating, the first valve and the second valve are opened, the third valve and the atmosphere release valve are closed, the suction means is operated, and a suction force is applied to the holding means. When the waste liquid stored in the second water tank is drained while the first valve and the second valve are closed, the third valve and the atmosphere release valve are connected. There is provided a drainage mechanism of a processing apparatus characterized by being in an open state.

  According to the present invention, the first water reservoir tank is disposed in the suction path, and the waste liquid collected in the first water reservoir tank is collected by its own weight in the second water reservoir tank by opening the valve. Piping so that the pressure in the water tank and the pressure in the second water reservoir tank are the same, and by closing the valve, the second water tank is made independent of the suction path, and the waste liquid collected in the second water tank is removed. Since the drainage mechanism is configured to allow drainage, it is not necessary to provide two types of suction means, which is economical, and the suction means does not suck water and does not shorten its life.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the external appearance of a cutting device (dicing device) 2 that can divide a semiconductor wafer to which the drainage mechanism of the present invention can be diced into individual chips (devices).

  On the front side of the cutting device 2, there is provided operating means 4 for an operator to input instructions to the device such as machining conditions. In the upper part of the apparatus, there is provided a display means 6 such as a CRT for displaying a guidance screen for an operator and an image taken by an imaging means described later.

  As shown in FIG. 2, on the surface of the wafer W to be diced, the first street S1 and the second street S2 are formed orthogonally, and the first street S1 and the second street S2 A plurality of devices D are partitioned and formed on the wafer W.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer peripheral edge of the dicing tape T is attached to an annular frame F. As a result, the wafer W is supported by the frame F via the dicing tape T, and a plurality of wafers (for example, 25 sheets) are accommodated in the wafer cassette 8 shown in FIG. The wafer cassette 8 is placed on a cassette elevator 9 that can move up and down.

  Behind the wafer cassette 8, a loading / unloading means 10 for unloading the wafer W before cutting from the wafer cassette 8 and loading the wafer after cutting into the wafer cassette 8 is disposed. Between the wafer cassette 8 and the loading / unloading means 10, a temporary placement area 12, which is an area on which a wafer to be carried in / out, is temporarily placed, is provided. Positioning means 14 for positioning at a certain position is provided.

  In the vicinity of the temporary placement area 12, transport means 16 having a turning arm that sucks and transports the frame F integrated with the wafer W is disposed, and the wafer W carried to the temporary placement area 12 is It is attracted by the transport means 16 and transported onto the chuck table 18 and is sucked by the chuck table 18, and is held on the chuck table 18 by fixing the frame F by a plurality of fixing means 19.

  The chuck table 18 is configured to be rotatable and reciprocally movable in the X-axis direction. Above the movement path of the chuck table 18 in the X-axis direction, an alignment unit 20 that detects a street to be cut of the wafer W is provided. It is arranged.

  The alignment unit 20 includes an imaging unit 22 that images the surface of the wafer W, and can detect a street to be cut by a process such as pattern matching based on an image acquired by imaging. The image acquired by the imaging unit 22 is displayed on the display unit 6.

  On the left side of the alignment means 20, a cutting means 24 for cutting the wafer W held on the chuck table 18 is disposed. The cutting means 24 is configured integrally with the alignment means 20, and both move together in the Y-axis direction and the Z-axis direction.

  The cutting means 24 is configured by attaching a cutting blade 28 to the tip of a rotatable spindle 26 and is movable in the Y-axis direction and the Z-axis direction. The cutting blade 28 is located on the extended line of the imaging means 22 in the X-axis direction.

  In the cutting apparatus 2 configured as described above, the wafer W accommodated in the wafer cassette 8 is sandwiched by the frame F by the loading / unloading means 10, and the loading / unloading means 10 moves to the rear of the apparatus (Y-axis direction). When the nipping is released in the placing area 12, the placing area 12 is placed in the temporary placing area 12. Then, the wafer W is positioned at a certain position by the positioning means 14 moving in a direction approaching each other.

  Next, the frame F is adsorbed by the conveyance means 16, and the wafer W integrated with the frame F is conveyed to the chuck table 18 by the rotation of the conveyance means 16 and is held by the chuck table 18. Then, the chuck table 18 moves in the X-axis direction, and the wafer W is positioned directly below the alignment means 20.

  The image used for pattern matching at the time of alignment in which the alignment unit 20 detects a street to be cut needs to be acquired in advance before cutting. Therefore, when the wafer W is positioned directly below the alignment unit 20, the imaging unit 22 captures the surface of the wafer W and causes the display unit 6 to display the captured image.

  The operator of the cutting apparatus 2 operates the operation unit 4 to move the image pickup unit 22 slowly and also move the chuck table 18 as necessary to search for a pattern that is a pattern matching target.

  When the operator determines a key pattern, an image including the key pattern is stored in a memory provided in the controller of the cutting apparatus 2. Further, the distance between the key pattern and the center line of the streets S1 and S2 is obtained by a coordinate value or the like, and the value is also stored in the memory.

  Further, by moving the image pickup means 22, an interval between the adjacent streets (street pitch) is obtained by a coordinate value or the like, and the street pitch value is also stored in the memory of the controller.

  At the time of cutting along the street of the wafer W, the alignment unit 20 performs pattern matching between the stored key pattern image and the image actually acquired by the imaging unit 22.

  When the patterns match, the cutting means 24 is moved in the Y-axis direction by the distance between the key pattern and the street center line, thereby aligning the street to be cut with the cutting blade 28.

  In a state where the street to be cut and the cutting blade 28 are aligned, the chuck table 18 is moved in the X-axis direction, and the cutting blade 28 is rotated at a high speed while supplying cutting water. When lowered, the aligned street is cut.

  By performing cutting while feeding the cutting means 24 in the Y-axis direction by the street pitch stored in the memory, all the streets S1 in the same direction are cut. Furthermore, when the chuck table 18 is rotated by 90 ° and then the same cutting as described above is performed, the streets S2 are all cut and divided into individual devices D.

  The wafer W that has been cut is moved in the X-axis direction by the chuck table 18 and is then gripped by the transfer means 25 that can move in the Y-axis direction and transferred to the cleaning device 27. The cleaning device 27 cleans the wafer by rotating the wafer W at a low speed (for example, 300 rpm) while jetting water from the cleaning nozzle.

  After cleaning, while rotating the wafer W at a high speed (for example, 3000 rpm), air is ejected from the air nozzle to dry the wafer W, and then the wafer W is adsorbed by the conveying means 16 and returned to the temporary storage area 12, and further carried in and out. By means 10, the wafer W is returned to the original storage location of the wafer cassette 8.

  When cutting the semiconductor wafer W supported by the annular frame F via the dicing tape T as in the above-described embodiment, the suction chuck 18a of the chuck table 18 is as shown in the drainage mechanism 60 of FIG. It is formed from a porous material such as porous ceramic.

  On the other hand, when cutting a generally hard workpiece such as a ceramic substrate, a chuck table for direct placement formed of a metal such as SUS is used instead of the chuck table 18. The drainage mechanism 60 can be applied to any type of chuck table.

  In FIG. 3, reference numeral 30 denotes a vacuum suction source, which includes an ejector 32 having a throttle 34 and a high-pressure air source 36. When air is supplied from the high-pressure air source 36 to the ejector 32, a negative pressure is generated by the throttle 34. This negative pressure is used for the suction force of the chuck table 18.

  The chuck table 18 and the ejector 32 are connected by a first connecting pipe 38, and a first water tank 40 is disposed in the middle of the first connecting pipe 38. A second connecting pipe 42 is provided so as to hang from the lower end of the first water tank 40, and the other end of the second connecting pipe 42 is connected to the upper part of the second water tank 44.

  A first valve 52 is inserted in the middle of the second connecting pipe 42. The second water tank 44 and the ejector 32 are connected by a third connecting pipe 46, and a second valve 54 is inserted in the middle of the third connecting pipe 46.

  A pipe line 50 that hangs down from the lower end of the second water reservoir tank 44 and communicates with the drain 48 is disposed, and a third valve 56 is inserted in the middle of the pipe line 50. An air release valve 58 is inserted into a pipe line 57 connected to the upper end portion of the second water reservoir tank 44.

  Hereinafter, the operation of the above-described drainage mechanism 60 will be described. In order to cut the wafer W, the vacuum suction source 30 is operated, the wafer W is sucked and held via the dicing tape T by the suction chuck 18a of the chuck table 18, and the cutting blade 28 is cut while supplying the cutting water. The wafer is cut by

  At the start of the cutting operation, cutting is performed with all the first to third valves 52, 54, and 56 and the atmosphere release valve 58 closed. The cutting water sucked through the suction chuck 18 a of the chuck table 18 gradually accumulates in the first water tank 40.

  When the water level rises to a predetermined water level, the first valve 52 and the second valve 54 are opened. Thereby, since both the water reservoir tanks 40 and 44 are connected to the ejector 32, the pressure in the 1st water reservoir tank 40 and the pressure in the 2nd water reservoir tank 44 become substantially the same.

  As a result, the cutting water accumulated in the first water tank 40, that is, the waste liquid, falls due to its own weight and moves into the second water tank 44. Thereby, the cutting water in the 1st water tank 40 becomes almost empty.

  When the cutting water in the second water reservoir tank 44 reaches a predetermined water level, the first valve 52 and the second valve 54 are closed, and the third valve 56 and the atmosphere release valve 58 are opened, whereby the second water reservoir The cutting water accumulated in the tank 44 is pushed to the atmospheric pressure and drained to the drain 48.

  After confirming that all of the cutting water in the second water reservoir tank 44 has been drained to the drain 48, the first to third valves 52, 54, 56 and the atmosphere release valve 58 are closed, and the above-described operation is repeated. Only the third valve 56 and the air release valve 58 may be closed so that the cutting water is accumulated in the second water reservoir tank 44 via the first water reservoir tank 40.

  In the present embodiment, it is preferable that the capacity of the second water tank 44 is set larger than the capacity of the first water tank 40. Thereby, a certain amount of cutting water can be stored in the 2nd water tank 44, and the frequency | count of the drainage operation | movement to a drain can be reduced.

  The detection of the predetermined water level in the first and second water reservoir tanks 40, 44 is preferably performed by, for example, a water level meter. If the water level meter detects the predetermined water level, the first to third water levels are detected according to the above description. The control means controls the opening and closing of the valves 52, 54, and 56 and the atmosphere release valve 58.

  However, the amount of water in the first and second water tanks 40 and 44 may be detected visually. In this case, the opening and closing of the first to third valves 52, 54 and 56 and the opening of the air release valve 58 are performed. Opening and closing is controlled manually.

  According to the drainage mechanism 60 described above, the cutting water is not sucked into the ejector 32 constituting the vacuum suction source 30. Therefore, the drainage mechanism can be provided economically with a simple configuration using only one vacuum suction source, and since water is not sucked, the life of the vacuum suction source 30 is shortened and the suction force is prevented from being lowered. .

  In the above description, the example in which the drainage mechanism 60 is applied to the chuck table 18 of the cutting apparatus has been described. However, the application example of the drainage mechanism of the present invention is not limited to this, and for example, as shown in FIG. It can also be used for the drainage mechanism of the chuck table of the grinding device. A schematic configuration of the grinding device 62 will be described with reference to FIG.

  FIG. 4 shows an external perspective view of the grinding device 62 provided with the drainage mechanism of the embodiment of the present invention. Reference numeral 64 denotes a housing of the grinding device 62, and a column 66 is erected on the rear side of the housing 64. A pair of guide rails 68 extending in the vertical direction are fixed to the column 66.

  A grinding unit (grinding means) 70 is mounted along the pair of guide rails 68 so as to be movable in the vertical direction. The grinding unit 70 includes a spindle housing 72 and a support portion 74 that holds the spindle housing 72, and the support portion 74 is attached to a moving base 76 that moves up and down along a pair of guide rails 68. Yes.

  The grinding unit 70 includes a spindle 78 rotatably accommodated in a spindle housing 72, a wheel mount 80 fixed to the tip of the spindle 78, and a plurality of grinding wheels that are screwed to the wheel mount 80 and arranged in an annular shape. A grinding wheel 82 having an electric motor for rotating the spindle 78 is included.

  The grinding device 62 includes a grinding unit moving mechanism 88 including a ball screw 84 that moves the grinding unit 70 in the vertical direction along a pair of guide rails 68 and a pulse motor 86. When the pulse motor 86 is driven, the ball screw 84 rotates and the moving base 76 is moved in the vertical direction.

  A recess 64a is formed on the upper surface of the housing 64, and a chuck table mechanism 90 is disposed in the recess 64a. The chuck table mechanism 90 has a chuck table 92 and is moved in the Y-axis direction between a wafer attaching / detaching position A and a grinding position B facing the grinding unit 70 by a moving mechanism (not shown). 94 and 96 are bellows. On the front side of the housing 64, an operation panel 98 is provided for an operator of the grinding device 62 to input grinding conditions and the like.

  The grinding operation of the grinding device 62 configured as described above will be briefly described below. On the chuck table 92 positioned at the wafer attachment / detachment position A shown in FIG. 4, the wafer W having a protective tape adhered to the surface is sucked and held with the protective tape down. The chuck table 92 is connected to the drainage mechanism 60 shown in FIG. Next, the chuck table 92 is moved in the Y-axis direction and positioned at the grinding position B.

  For the wafer W positioned in this manner, while rotating the chuck table 92 at, for example, 300 rpm, the grinding wheel 82 is rotated in the same direction as the chuck table 92, for example, at 6000 rpm, and the grinding unit moving mechanism 88 is operated. Then, the grinding wheel mounted on the grinding wheel 82 is brought into contact with the back surface of the wafer W to perform grinding.

  When performing this grinding, grinding is performed while supplying grinding water to the grinding wheel 82 by a grinding water supply means (not shown). The chuck table 92 operates the vacuum suction source 30 shown in FIG. 3 to suck and hold the wafer W.

  The grinding water sucked through the chuck table 92, that is, the waste liquid, is the same as that described in the drainage mechanism 60 of the chuck table 18 of the cutting apparatus 2 with reference to FIG. Since the water is sequentially stored in the tank 44 and drained to the drain 48 as necessary, the ejector 32 is prevented from sucking the grinding water, and the life of the ejector 32 is shortened by the suction of the grinding water and the suction force is reduced. Is prevented.

It is a schematic perspective view of the cutting device provided with the drainage mechanism of the present invention. It is a surface side perspective view of the semiconductor wafer supported by the annular frame via the dicing tape. It is a block diagram of the drainage mechanism which concerns on this invention embodiment. It is a schematic perspective view of the grinding device provided with the drainage mechanism of the present invention.

Explanation of symbols

2 Cutting device 18 Chuck table 28 Cutting blade 30 Vacuum suction source 32 Ejector 34 Restriction 36 High pressure air source 40 First water tank 44 Second water tank 48 Drain 52 First valve 54 Second valve 56 Third valve 58 Air release valve 62 Grinding device 82 Grinding wheel 92 Chuck table

Claims (2)

Processing that includes holding means for sucking and holding a workpiece, processing means for performing processing while supplying processing water to the workpiece held by the holding means, and suction means for transmitting a suction force to the holding means A drainage mechanism of a processing device for draining waste liquid sucked from the holding means of the device,
A first connecting pipe that connects the holding means and the suction means;
A first water tank disposed in the middle of the first connecting pipe;
A second connecting pipe that is suspended from the first water tank;
A second water tank connected to the second connecting pipe;
A third connecting pipe connecting the second water reservoir tank and the suction means;
A drain that is suspended from the second water reservoir;
A first valve disposed in the second connecting pipe;
A second valve disposed in the third connecting pipe;
A third valve disposed in a conduit connected to the drain;
An atmosphere release valve disposed at the top of the second water reservoir tank;
When the suction means is actuated to transmit suction force to the holding means to accumulate waste liquid in the second water reservoir tank, the first valve and the second valve are opened and the third valve is opened. The valve and the air release valve are closed,
When draining the waste liquid stored in the second water reservoir tank while operating the suction means to transmit the suction force to the holding means, the first valve and the second valve are closed. And a drainage mechanism for the processing apparatus, wherein the third valve and the atmosphere release valve are opened.   The drainage mechanism of the processing apparatus according to claim 1, wherein the suction means includes an ejector.

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