JP2019089136A - Byte cutting device and method for processing work-piece - Google Patents

Abstract

To provide a byte cutting device whose processing efficiency is improved by suppressing a cutting blade of a byte tool from being abraded.SOLUTION: The byte cutting device comprises: a chuck table for holding a work-piece; a byte tool having a cutting blade made of diamond for byte-cutting a surface of the work-piece held on the chuck table; a byte wheel having the byte tool arranged on a lower surface thereof; a byte cutting unit for supporting the byte wheel rotatably; and a tank that has a space which can store liquid and stores the chuck table in the space, which has function of submerging the work-piece held on the chuck table into liquid by storage of the liquid in the space. The space has a region where the byte tool can move when the work-piece submerged into the liquid is byte-cut with the byte tool.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cutting tool for cutting a workpiece on which a device is formed on the surface, and a processing method for processing the workpiece.

  In the manufacturing process of device chips used for electronic devices such as mobile phones and personal computers, first, a plurality of intersecting planned lines are set on the surface of a wafer made of a material such as a semiconductor. Then, devices such as IC (Integrated Circuit) and LSI (Large Scale Integration) are formed in each area divided by the planned dividing line. Furthermore, a device chip can be formed by thinning the wafer to a predetermined thickness and then dividing the wafer along the dividing line.

  2. Description of the Related Art In recent years, mounting technology called flip chip bonding has been put to practical use in order to save a space required for mounting when mounting a device chip on a predetermined mounting target. In flip chip bonding, metal bumps called bumps of about 10 μm to 100 μm in height are formed on the surface side of the device through the wiring substrate, and these bumps are made to face the electrodes formed on the mounting object. Mounting technology for direct bonding. The bumps function as terminals of the device chip, and are connected to the device through the wiring substrate and the thin metal wires.

  Furthermore, as a semiconductor packaging technology, bumps are formed directly on the device surface without performing internal wiring with metal fine wires, and the wafer surface and the bumps are covered and sealed with a sealing material, and the wafers are individualized. The technology of dividing into device chips has been put to practical use. The packaging technology is called WL-CSP (Wafer-level Chip Size Package) (see Patent Document 1).

  Since the heights of the plurality of bumps formed on the surface of the wafer are not necessarily uniform, even if the plurality of bumps are directly joined to the electrode formed on the mounting target of the device chip, they are uniformly joined. Is not easy. Therefore, the upper part of the sealing material and the upper part of the bump are cut by a cutting tool equipped with a cutting tool having a cutting edge made of diamond, thereby thinning the sealing material and setting the height of the bump A processing method to make it uniform has been developed (see Patent Document 2).

JP 2001-7135 A Japanese Patent Application Laid-Open No. 2000-173954

  A cutting tool for cutting a surface side of a wafer on which a sealing material and a bump are formed is a cutting tool that simultaneously has the sealing material having high machining resistance during cutting and a bump formed of metal. Cut. Therefore, the processing load and processing heat generated by the cutting of the cutting tool strongly work on the cutting tool, and the cutting edge of the cutting tool is abraded severely. Furthermore, when cutting with a cutting tool, cuttings are generated, and the cuttings scatter on the surface of the wafer. Then, since the cuttings are caught in the cutting tool at the time of further cutting the cutting tool, the cutting tool wears more violently.

  Since it is not possible to carry out further cutting with a highly worn tool, it is necessary to change the tool frequently. While changing the cutting tool, the cutting tool can not be used, and the replacement cutting tool is expensive. Therefore, the processing efficiency of the cutting tool becomes low, which causes a problem.

  The present invention has been made in view of such problems, and the object of the present invention is to provide a cutting tool and a method for processing a workpiece, which can suppress the wear of the cutting edge of the cutting tool and improve the processing efficiency. It is to be.

  According to one aspect of the present invention, there is provided a chuck table for holding a workpiece, a cutting tool having a cutting edge made of diamond for cutting the surface of the workpiece held by the chuck table, and the cutting tool A tool wheel provided on the lower surface, a tool cutting unit rotatably supporting the tool wheel, and a tank having a space for storing liquid and containing the chuck table in the space, the liquid in the space Has a function of immersing the workpiece held on the chuck table in the liquid by storing the water, and the space is used when cutting the workpiece sunk in the liquid with the cutting tool There is provided a cutting tool according to claim 1, wherein the cutting tool has a movable region.

  In one aspect of the present invention, the bath is provided with four side walls integrally surrounding and defining the space, and the upper end of the side wall is an upper surface of the workpiece held by the chuck table. It may be higher than that. Alternatively, the tank has a side wall which surrounds and defines the space, the side wall has a curved surface, and the upper end of the side wall is higher than the upper surface of the workpiece held by the chuck table. It is also good.

  A cutting tool according to an aspect of the present invention is a workpiece including a wafer, a device formed on the surface of the wafer, a bump on the device, and the device and a sealing material on the bump. A method of processing a workpiece using a cutting tool, comprising: a holding step for holding the workpiece on the chuck table; supplying a liquid to the space of the tank to hold the workpiece on the chuck table Machining a workpiece comprising: a liquid supply step of sinking a workpiece into the liquid; and a cutting step of cutting the workpiece to expose the bumps from the encapsulant. The method is also an aspect of the present invention.

  A cutting tool according to an aspect of the present invention includes a cutting tool having a cutting edge for cutting a surface of a workpiece, and a cutting tool wheel having the cutting tool on the lower surface. The cutting apparatus further includes a tank having a space in which liquid can be stored, and in which the chuck table is accommodated. When the workpiece is held on the chuck table and the liquid is supplied to the space, the workpiece is submerged in the liquid. Since the space has an area in which the cutting tool can move, the cutting tool can cut the workpiece while being submerged in the liquid.

  Since cutting chips generated by cutting the tool are dispersed in the liquid, the cutting chips are less likely to be caught in the cutting tool during further cutting of the cutting tool.

  In addition, since the liquid always contacts the cutting tool during cutting the cutting tool, the processing heat generated by the processing is efficiently removed from the cutting tool. As a result, wear of the cutting tool can be suppressed, the frequency of changing the cutting tool can be reduced, and the processing efficiency of the cutting machine can be increased.

  Therefore, the present invention provides a method of processing a workpiece that can suppress the wear of the cutting edge of the cutting tool and improve the processing efficiency of the cutting tool.

FIG. 1A is a perspective view schematically showing a workpiece having bumps and a sealing material provided on the surface, and FIG. 1B shows a substrate having bumps and a sealing material provided on the surface. It is sectional drawing which shows a workpiece schematically. It is a perspective view which shows a cutting tool typically. FIG. 3A is a perspective view schematically showing an example of the X-axis moving table and the X-axis moving mechanism of the cutting tool, and FIG. 3B is the X-axis moving table and the X axis of the cutting tool It is a perspective view which shows typically another example of a moving mechanism. It is a partial section side view showing a cutting tool step typically.

  Embodiments according to one aspect of the present invention will be described with reference to the attached drawings. First, the to-be-processed object of the cutting tool which concerns on this embodiment is demonstrated using FIG. 1 (A) and FIG. 1 (B). FIG. 1A is a perspective view schematically showing a workpiece. The workpiece 5 includes the wafer 1, the bumps 7, and the sealing material 3.

  The wafer 1 is a substantially disc-like substrate made of, for example, a material such as silicon, SiC (silicon carbide), or other semiconductor, or a material such as sapphire, glass, or quartz. A plurality of planned dividing lines (not shown) are set in a lattice on the surface 1a of the wafer 1, and in each area partitioned by the planned dividing lines, IC (Integrated Circuit), LSI (Large Scale Integration), etc. The device 7a is formed. Finally, when the wafer 1 is divided along the dividing lines, individual device chips are formed.

  FIG. 1B is a cross-sectional view schematically showing the workpiece 5. The bumps 7 are formed of a conductive material such as metal, and serve as terminals of device chips formed by dividing the wafer 1. Before the wafer 1 is divided, the workpiece 5 is cut by a cutting tool equipped with a cutting tool, and the upper portion of the sealing material 3 covering the bumps 7 and the upper portion of the bumps 7 are partially removed. Then, since the bumps 7 are exposed from the sealing material 3, the bumps 7 can be joined to the mounting target electrodes when the device chip is mounted on a predetermined mounting target.

  Next, a cutting tool according to an aspect of the present invention will be described with reference to FIG. FIG. 2 is a perspective view schematically showing a cutting tool 2 for cutting the workpiece 5.

  The cutting tool 2 has a base 4 that supports each component. Cassette mounting bases 6 a and 6 b are provided on the top surface of the front side portion of the base 4. On the cassette mounting table 6a, for example, a cassette 8a containing the workpiece 5 before cutting with a cutting tool is mounted. On the cassette mounting table 6b, for example, a cassette 8b for storing the workpiece 5 after cutting of the cutting tool is mounted. On the base 4, a transfer robot 10 for transferring the workpiece 5 adjacent to the cassette mounting tables 6a and 6b is installed.

  Further, a positioning table 12 for determining the position of the workpiece 5 with a plurality of positioning pins, a loading mechanism (loading arm) 14 for placing the workpiece 5 on the chuck table 20 and a workpiece An unloading mechanism (unloading arm) 16 for unloading the workpiece 5 from the chuck table 20 and a cleaning unit 50 for cleaning and spin-drying the workpiece 5 which has been cut by a tool are provided.

  An opening 4 a is provided on the upper surface of the rear side portion of the base 4. In the opening 4a, there is provided an X-axis moving table 18 on which a chuck table 20 for sucking and holding the workpiece 5 is placed on the upper surface. The X-axis moving table 18 is movable in the X-axis direction by an X-axis direction moving mechanism. FIG. 3A is a perspective view schematically showing an example of the X-axis moving table 18 and the X-axis moving mechanism.

  The X-axis moving mechanism includes a pair of X-axis guide rails 18a extending in the X-axis direction, an X-axis ball screw 18b extending in the X-axis direction between the X-axis guide rails, and the X-axis ball screw 18b. And an X-axis pulse motor 18c connected to one end. A nut portion (not shown) is provided on the back surface side (rear surface side) of the X-axis moving table 18, and an X-axis ball screw 18b is screwed into this nut portion.

  When the X axis ball screw 18b is rotated by the X axis pulse motor 18c, the X axis moving table 18 moves in the X axis direction along the X axis guide rail 18a. The X-axis moving table 18 is a loading / unloading area 22 where the workpiece 5 is attached / detached on the chuck table 20 by the X-axis moving mechanism, and a processing where the workpiece 5 sucked and held on the chuck table 20 is cut It is located in the area 24.

  The upper surface of the chuck table 20 serves as a holding surface 20 a for holding the workpiece 5. The chuck table 20 internally includes a suction path whose one end communicates with the holding surface 20 a of the chuck table 20 and whose other end is connected to a suction source (not shown). When the suction source is operated, a negative pressure acts on the workpiece 5 placed on the holding surface 20 a, and the workpiece 5 is sucked and held on the chuck table 20.

  In the periphery of the chuck table 20 on the X-axis moving table 18, a side wall 48a constituting the tank 48 is disposed. The tank 48 has a space 48 c for storing liquid, and the chuck table 20 is accommodated in the space 48 c. The cutting tool 2 includes a liquid supply device (not shown) capable of supplying a liquid to the tank 48.

  When the workpiece 5 is held on the chuck table 20 and the liquid is supplied to the space 48c and the liquid is stored in the space 48c, the workpiece 5 can be sunk in the liquid. The workpiece 5 is cut by a cutting tool 52 described later while being submerged in the liquid. In order to sink the workpiece 5 in the liquid, the sidewall 48 a of the tank 48 is formed such that the upper end is higher than the upper surface of the workpiece 5 held by the chuck table 20.

  The X-axis moving table 18 is provided with a discharge path (not shown) for the liquid, and the bottom of the tank 48 is provided with a drain port 48b connected to one end of the discharge path. A drainage valve (not shown) is provided in the drainage path, and after cutting of the cutting tool is completed, the drainage valve is opened before the workpiece 5 is carried out from the chuck table 20, and the liquid is It is discharged from the tank 48.

  The tank 48 includes, for example, four plate-like side walls 48 a integrally surrounding the space 48 c as shown in FIG. 3A, and is formed in a box shape. In addition, the tank 48 includes, for example, a side wall 48a having a curved surface surrounding the space 48c as shown in FIG. 3 (B). The side wall 48a having the curved surface is formed such that an area necessary for the chuck table 20 and the tool wheel 44 described later to simultaneously enter the space 48c is secured in the space 48c.

  As shown in FIG. 2, a cutting tool cutting unit 26 for cutting a workpiece 5 is disposed above the processing area 24. A support 28 is provided upright at the rear end of the base 4 of the cutting tool 2, and the cutting unit 26 is supported by the support 28. A pair of Z-axis guide rails 30 extending in the Z-axis direction is provided on the front surface of the support portion 28. A Z-axis moving plate 32 is slidably attached to each Z-axis guide rail 30.

  A nut portion (not shown) is provided on the back surface side (rear surface side) of the Z-axis moving plate 32, and a Z-axis ball screw 34 parallel to the Z-axis guide rail 30 is screwed into this nut portion. ing. A Z-axis pulse motor 36 is connected to one end of the Z-axis ball screw 34. When the Z-axis ball screw 34 is rotated by the Z-axis pulse motor 36, the Z-axis moving plate 32 moves in the Z-axis direction along the Z-axis guide rail 30.

  A tool cutting unit 26 is fixed to the lower part of the front side of the Z-axis moving plate 32. By moving the Z-axis moving plate 32 in the Z-axis direction, the tool cutting unit 26 can be moved in the Z-axis direction.

  The tool cutting unit 26 includes a spindle 40 rotated by a motor connected to the base end side, and a tool wheel 44 fixed by a fixing tool 46 to a mount 42 disposed on the tip end side of the spindle 40. The motor is provided in a spindle housing 38, and when the motor is operated, the cutting wheel 44 rotates according to the rotation of the spindle 40.

  A cutting tool 52 (see FIG. 4) is mounted on the lower surface of the cutting wheel 44. The cutting tool 52 is provided with a cutting edge 52a (see FIG. 4) which contacts the workpiece 5 and cuts the workpiece 5 by cutting. The cutting blade 52a is made of, for example, a diamond.

  The cutting tool 26 is lowered along the Z-axis direction, and the lower end of the cutting edge 52a is positioned at a height that reaches the bumps 7 formed on the surface 1a of the wafer 1. Then, when the tool wheel 44 is rotated and the chuck table 20 is moved in the X-axis direction, the upper portion of the sealing material 3 and the upper portion of the bumps 7 are cut and the bumps 7 are cut from the sealing material 3 Exposed.

  The cutting tool 52 cuts the sealing material 3 with high machining resistance and the bumps 7 formed of metal. Therefore, the processing load and the processing heat generated by the cutting of the cutting tool strongly work on the cutting tool 52, and the cutting edge 52a of the cutting tool 52 is worn a lot. Further, when cutting with a cutting tool, cuttings are generated, and the cuttings scatter on the surface 1 a of the wafer 1. Then, since the cuttings are caught in the cutting edge 52a of the cutting tool 52 at the time of further cutting the cutting tool, the cutting tool 52 wears even more violently.

  Therefore, in the cutting tool 2 according to one aspect of the present invention, the space 48c inside the tank 48 is filled with the liquid 48d at the time of cutting the cutting tool, and the cutting edge 52a of the cutting tool 52 is submerged in the liquid 48d. Then, since the processing heat and cutting chips generated by cutting the cutting tool are dispersed in the liquid 48d, the wear of the cutting tool 52 can be suppressed and the frequency of replacement of the cutting tool 52 can be reduced, thereby enhancing the processing efficiency of the cutting machine. Be

  Next, a method of processing the workpiece 5 in which the workpiece 5 is cut by using the cutting tool 2 will be described. The processing method of the workpiece 5 includes a holding step of holding the workpiece 5 on the chuck table 20, and a liquid feeding step of supplying the liquid 48d to the space 48c of the tank 48 to sink the workpiece 5 in the liquid 48d. And a cutting step of cutting the workpiece 5. Hereinafter, each step of the processing method of the said workpiece 5 is demonstrated.

  First, the holding step will be described. The workpiece 5 to be cut by the cutting device 2 is carried into the cutting device 2 while being accommodated in the cassette 8a. When the cassette 8a is placed on the cassette mounting table 6a, the transport robot 10 takes out the workpiece 5 from the cassette 8a.

  The workpiece 5 is carried into the positioning table 12 by the transfer robot 10, and the positioning table 12 is operated to align the center of the workpiece 5 with the center of the positioning table 12. Then, the workpiece 5 is placed by the loading mechanism (loading arm) 14 on the holding surface 20 a of the chuck table 20 placed on the X-axis moving table 18 positioned in the loading / unloading area 22. At this time, the back surface 1b side of the wafer 1 is directed downward, and the back surface 1b is brought into contact with the holding surface 20a.

  After the workpiece 5 is placed on the holding surface 20 a of the chuck table 20, a suction source (not shown) of the chuck table 20 is operated to apply a negative pressure to the workpiece 5. The workpiece 5 is held by suction. Then, the sealing material 3 of the workpiece 5 is exposed upward.

  Next, the liquid supply step will be described. After the holding step is performed, the liquid 48d is supplied from the liquid supply device to the space 48c of the tank 48 above the X-axis moving table 18 to sink the workpiece 5 in the liquid 48d. For example, the liquid 48 d may be pure water, and the liquid 48 d may contain a surfactant.

  The liquid 48 d may be scattered from the space 48 c by the cutting tool 52 rotating during cutting of the work 5, and the work 5 may be exposed from the liquid 48 d. Therefore, for example, the liquid 48d may be continuously supplied from the liquid supply device to the space 48c of the tank 48 while performing a cutting step described later.

  Next, the tool cutting step will be described. After performing the liquid supply step, the X-axis moving table 18 is moved to the processing area 24. Then, the tool wheel 44 is rotated to lower the tool cutting unit 26 along the Z-axis direction, and the lower end of the cutting edge 52 a is positioned at a height position to reach the bump 7 of the workpiece 5. Thereafter, when the chuck table 20 is moved in the X-axis direction, the upper portion of the sealing material 3 of the workpiece 5 and the upper portion of the bumps 7 are cut by the cutting tool 52 and the bumps 7 are exposed from the sealing material 3 Be done.

  FIG. 4 is a side view schematically showing the tool cutting step. When cutting the workpiece 5, the cutting tool 52 is immersed in the liquid 48d and continues to be cooled by the liquid 48d. The cutting is performed by lowering the cutting unit 26 at a position adjacent to the chuck table 20 and moving the X-axis moving table 18 in the X-axis direction while rotating the cutting wheel 44. Therefore, the tank 48 is formed in a size and shape that allows the cutting tool 52 to rotate at a position adjacent to the chuck table 20.

  After cutting of the cutting tool by the cutting tool 52 is completed, the X-axis moving table 18 is moved to the loading / unloading area 22, and the liquid 48d is discharged from the drainage port 48b. Thereafter, the suction by the chuck table 20 is released, and the workpiece 5 is unloaded to the cleaning unit 50 by the unloading mechanism (unloading arm) 16. Then, the workpiece 5 is cleaned by the cleaning unit 50 and dried. The cleaned workpiece 5 is accommodated by the transfer robot 10 in the cassette 8 b placed on the cassette mounting table 6 b.

  In the method of processing the workpiece 5, when the cutting step is performed, the space 48c inside the tank 48 is filled with the liquid 48d. Then, the cutting edge 52a of the cutting tool 52 sinks in the liquid 48d, and the processing heat and cutting chips generated by cutting the cutting tool are dispersed in the liquid 48d. Therefore, the wear of the cutting tool 52 can be suppressed, the frequency of replacement of the cutting tool 52 can be reduced, and the processing efficiency of the cutting tool can be enhanced.

  In addition, this invention is not limited to the description of the said embodiment, It can change variously and can be implemented. For example, a groove may be formed in the sealing material 3 before cutting the workpiece 5 by cutting. In this case, since the volume of the sealing material 3 removed by the cutting tool 52 by cutting the cutting tool is reduced, it is possible to suppress the generation of cutting chips and cutting heat by cutting the cutting tool.

  The structures, methods, and the like according to the above embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 1 wafer 1a front surface 1b back surface 3 sealing material 5 workpiece 7 bump 7a device 2 bite cutting device 4 base 4a opening 6a, 6b cassette mounting base 8a, 8b cassette 10 transport robot 12 positioning table 14 loading mechanism (loading arm)
16 Unloading mechanism (unloading arm)
18 X axis moving table 18a X axis guide rail 18b X axis ball screw 18c X axis pulse motor 18d cover 20 chuck table 20a holding surface 22 carry in / out area 24 machining area 26 bite cutting unit 28 support 30 Z axis guide rail 32 Z axis Moving plate 34 Z-axis ball screw 36 Z-axis pulse motor 38 spindle housing 40 spindle 42 mount 44 bite wheel 46 fixture 48 tank 48a side wall 48b outlet 48c space 48d liquid 50 cleaning unit 52 bite tool 52a cutting blade

Claims (4)

A chuck table for holding a workpiece;
A cutting tool having a cutting edge made of diamond for cutting a surface of a workpiece held by the chuck table;
A cutting tool wheel having the cutting tool on its lower surface;
A cutting tool unit rotatably supporting the cutting tool wheel;
And a tank for containing the chuck table in the space, wherein the liquid is stored in the space to sink the workpiece held by the chuck table in the liquid. Has a function,
A cutting tool characterized in that the space has an area where the cutting tool can move when cutting the workpiece immersed in the liquid with the cutting tool. The vessel comprises four side walls which surround and define the space together,
2. The cutting tool according to claim 1, wherein the upper end of the side wall is higher than the upper surface of the workpiece held by the chuck table. The vessel comprises a side wall surrounding and defining the space,
The side wall has a curved surface,
2. The cutting tool according to claim 1, wherein the upper end of the side wall is higher than the upper surface of the workpiece held by the chuck table. A workpiece comprising a wafer, a device formed on the surface of the wafer, a bump on the device, and the device and the sealing material on the bump are described in any one of claims 1 to 3. A method of machining a workpiece by cutting a cutting tool using a cutting tool according to
A holding step for holding the workpiece on the chuck table;
Supplying liquid to the space of the tank to sink the workpiece held on the chuck table in the liquid;
A cutting step of cutting the workpiece to expose the bumps from the encapsulant;
A method of processing a workpiece, comprising: