Cutting apparatus

Abstract

To provide a cutting apparatus capable of efficiently removing cutting chips attached to a bottom surface of a groove.SOLUTION: A cutting apparatus (1) includes: a cutting mechanism (51) cutting a wafer (W) held on a chuck table (21) with a cutting blade (54) to form a groove (M) in the wafer; a Y-axis movement mechanism (31) moving the cutting mechanism in a Y-axis direction that is in parallel to the holding surface (211) of the chuck table and perpendicular to an X-axis direction being a cutting direction; a cleaning nozzle (61) jetting fluid toward the bottom surface of the groove to clean the bottom surface; and a nozzle movement mechanism (62) moving the cleaning nozzle in the Y-axis direction. An index amount setting section (71) sets an index amount (D) in the Y-axis direction, the index amount being an interval between streets (L) of the wafer, and a control section (70) controls the nozzle movement mechanism such that the cleaning nozzle jets the fluid onto the bottom surface of one groove that is ahead by at least one index amount from a street cut with the cutting blade.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a cutting device that cuts a wafer with a cutting blade to form a groove. [Background technology]

[0002] Patent Documents 1 and 2 disclose a cutting device that cuts a cutting blade into the surface of a plate-shaped workpiece to a predetermined depth and moves a chuck table that holds the plate-shaped workpiece to form a groove in the plate-shaped workpiece. After the groove is formed, tape is applied to the surface of the plate-shaped workpiece so as to close the groove, and the wafer and ring frame are integrated via the tape, and the back surface of the plate-shaped workpiece is ground to divide it into chips. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-157723 A [Patent Document 2] JP 2016-157722 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the cutting process for forming the grooves in Patent Documents 1 and 2, cutting chips may adhere to the bottom surface of the groove, and the cutting chips may adhere to the tape and cause air bubbles to form, resulting in a problem of a thinner chip.

[0005] In addition, Patent Document 1 is provided with a nozzle that sprays high-pressure water onto the top surface of a plate-shaped workpiece during cutting. However, Patent Document 1 sprays high-pressure water onto the surface of the plate-shaped workpiece in a predetermined width, and does not spray high-pressure water from the nozzle in accordance with the size of the chips after division. This causes problems such as insufficient cleaning of the grooves with high-pressure water and an increased amount of high-pressure water sprayed from the nozzle.

[0006] Patent Document 2 is equipped with a nozzle that injects high-pressure water into the groove immediately after cutting with the cutting blade during cutting work. However, Patent Document 2 has a problem in that the force of the high-pressure water injected from the nozzle is hindered by the spray of cutting water scattered by the rotation of the cutting blade, reducing the cleaning effect.

[0007] The present invention has been made in consideration of the above-mentioned points, and one of its objects is to provide a cutting device that can efficiently remove cutting chips adhering to the bottom surface of a groove. [Means for solving the problem]

[0008] a Y-axis moving mechanism for moving the cutting mechanism in a Y-axis direction perpendicular to the holding surface and perpendicular to the X-axis direction; and a cleaning nozzle for spraying fluid toward a bottom surface of the groove to clean the bottom surface. The cutting device according to one embodiment of the present invention includes a chuck table for holding a wafer having lattice-shaped streets by a holding surface, an X-axis moving mechanism for moving the chuck table in an X-axis direction which is the cutting direction of a cutting blade, a cutting mechanism for cutting the wafer held on the chuck table with the cutting blade to form grooves in the wafer, a Y-axis moving mechanism for moving the cutting mechanism in a Y-axis direction perpendicular to the X-axis direction and parallel to the holding surface, and a cleaning nozzle for spraying fluid toward a bottom surface of the groove to clean the bottom surface. The cutting device further includes a nozzle moving mechanism for moving the cleaning nozzle in the Y-axis direction, an index amount setting unit for setting an index amount in the Y-axis direction which is the distance between streets on the wafer held on the chuck table, and a control unit for controlling the cleaning nozzle to be positioned so that the cleaning nozzle is sprayed with fluid toward a bottom surface of one of the grooves which is at least one index amount before the street being cut by the cutting blade, based on a value of the index amount setting unit and the nozzle moving mechanism. Effect of the Invention

[0009] According to the present invention, the cleaning nozzle injects fluid into the groove that is at least one index amount before the street being cut, so that it is possible to prevent the cleaning power from being reduced by cutting water scattered by the rotation of the cutting blade. Furthermore, it is possible to prevent the amount of fluid injection from increasing. This makes it possible to efficiently remove cutting chips attached to the bottom surface of the groove. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of a cutting device according to an embodiment; [Diagram 2] FIG. 2 is an explanatory side view during cutting processing in the cutting device of the embodiment. [Diagram 3] FIG. 2 is an explanatory front view of the cutting device according to the embodiment during cutting processing. [Figure 4] FIG. 4A is an illustrative plan view during cutting of the grooves, and FIGS. 4B and 4C are plan views similar to FIG. 4A during cutting and cleaning of the grooves. [Diagram 5] FIG. 4B is a plan view similar to FIG. 4A, showing a modified example in which the cutting target is changed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the cutting device 1 according to the present embodiment will be described with reference to the attached drawings. The cutting device 1 according to the present embodiment is not limited to the configuration shown below, and can be modified as appropriate. In FIG. 1, for the sake of convenience, some members are omitted.

[0012] First, the overall configuration of the cutting device 1 will be described with reference to Fig. 1. Fig. 1 is a perspective view of the cutting device of the embodiment. The X-axis direction, Y-axis direction, and Z-axis direction shown in Fig. 1 are perpendicular to each other. The X-axis direction and the Y-axis direction are substantially horizontal directions, and the Z-axis direction is an up-down direction (vertical direction). In addition, in each of the following drawings, the front side in the X-axis direction is referred to as the +X side, the back side as the -X side, the left side in the Y-axis direction as the +Y side, the right side as the -Y side, and the upper side in the Z-axis direction may be referred to as the +Z side and the lower side as the -Z side.

[0013] As shown in FIG. 1, the cutting device 1 is configured to form a groove M in a wafer W, which is a workpiece held on a chuck table 21, using a cutting blade 54, and to wash away cutting chips generated during the formation of the groove M with cutting water.

[0014] The surface of the wafer W is divided into a plurality of regions by lattice-like streets L, and a device (not shown) is formed in each of the regions divided by the streets L.

[0015] The workpiece may be any member other than the wafer W that is to be cut by the cutting device 1, and may be, for example, a raw ceramic before sintering formed into a plate. The workpiece may be a semiconductor wafer in which semiconductor devices such as ICs and LSIs are formed on a semiconductor substrate such as silicon or gallium arsenide, or an optical device wafer in which optical devices such as LEDs are formed on an inorganic material substrate such as sapphire or silicon carbide. Furthermore, the workpiece may be a package substrate such as a CSP substrate, a printed circuit board, a metal substrate, or the like.

[0016] An X-axis moving mechanism 15 for moving the chuck table 21 in the X-axis direction, which is the cutting direction of the cutting blade 54, is disposed on the base 11. The X-axis moving mechanism 15 has a pair of guide rails 16 arranged on the base 11 and parallel to the X-axis direction, and a motor-driven X-axis table 17 slidably installed on the pair of guide rails 16. A nut portion (not shown) is formed on the rear side of the X-axis table 17, and a feed screw 18 is screwed into this nut portion. A drive motor 19 connected to one end of the feed screw 18 is rotated, whereby the chuck table 21 is fed for cutting along the pair of guide rails 16.

[0017] A chuck table 21 for holding the wafer W and a rotation mechanism 22 are provided on the X-axis table 17. A holding surface 211 is formed on the chuck table 21 using a porous ceramic material, and the wafer W is sucked and held by negative pressure generated on the holding surface 211. The holding surface 211 is connected to a suction source 212 (see FIGS. 2 and 3) that generates negative pressure. The rotation mechanism 22 is made up of a motor disposed below the chuck table 21 and a rotating shaft whose axial direction is the Z-axis direction (vertical direction), and the like, and rotates the chuck table 21 around the center of the holding surface 211. In addition, a gate-shaped standing wall portion 12 is provided on the upper surface of the base 11 so as to straddle the moving path of the chuck table 21.

[0018] The vertical wall portion 12 is provided with a Y-axis moving mechanism 31 that moves the cutting mechanism 51 in the Y-axis direction which is parallel to the holding surface 211 and perpendicular to the X-axis direction, and a Z-axis moving mechanism 41 that moves the cutting mechanism 51 in the Z-axis direction.

[0019] The Y-axis movement mechanism 31 has a pair of guide rails 34 parallel to the Y-axis direction arranged on the front surface of the standing wall portion 12, and a Y-axis table 35 slidably installed on the pair of guide rails 34. A nut portion (not shown) is formed on the rear surface side of the Y-axis table 35, and a feed screw 36 is screwed into the nut portion. A drive motor 37 is connected to one end of the feed screw 36 for the Y-axis table 35. The feed screw 36 is rotated by the drive motor 37, whereby the Y-axis table 35, the Z-axis movement mechanism 41, and the cutting mechanism 51 are moved in the Y-axis direction along the guide rails 34.

[0020] The Z-axis movement mechanism 41 has a pair of guide rails 44 arranged on the Y-axis table 35 and parallel to the Z-axis direction, and a Z-axis table 45 slidably installed on the pair of guide rails 44. A spindle housing 52 of a cutting mechanism 51 is connected to the lower end of the Z-axis table 45. A nut portion (not shown) is formed on the rear side of the Z-axis table 45, and a feed screw 46 is screwed into the nut portion. A drive motor 47 is connected to one end of the feed screw 46 for the Z-axis table 45. The feed screw 46 is rotated by the drive motor 47, whereby the Z-axis table 45 and the cutting mechanism 51 are moved (up and down) in the Z-axis direction along the guide rails 44.

[0021] Fig. 2 is an explanatory side view of the cutting device according to the embodiment during cutting processing. Fig. 3 is an explanatory front view of the cutting device according to the embodiment during cutting processing. As shown in Figs. 2 and 3, in the cutting mechanism 51, a spindle 53 is rotatably supported by a spindle housing 52, and a cutting blade 54 is attached to the tip (end on the +Y side) of the spindle 53. The cutting blade 54 is formed in a disk shape made of diamond abrasive grains bound with a bonding agent.

[0022] A blade cover 55 is fixed to the end of the spindle housing 52 on the +Y side, and the blade cover 55 covers the periphery of the cutting blade 54 except for approximately the lower half of the cutting blade 54. A cutting water nozzle 56 is provided on the +X side of the blade cover 55, and cutting water is supplied to the cutting water nozzle 56 from a cutting water supply source 57 (neither is shown in FIG. 3). The cutting water nozzle 56 supplies cutting water to the surface of the wafer W, and the cutting water washes away processing debris adhering to the wafer W.

[0023] A pair of blade cooling nozzles 58 are disposed on the blade cover 55 on both sides in the Y-axis direction, sandwiching the cutting blade 54. Cutting water is supplied to the blade cooling nozzles 58 from a cutting water supply source 57 (not shown in FIG. 3). Jet ports are formed on the opposing surfaces of the pair of blade cooling nozzles 58, and cutting water is supplied to the cutting blade 54 from both sides in the Y-axis direction through each jet port, and the cutting water hitting the side surface of the cutting blade 54 cools and cleans the machining point.

[0024] Returning to Fig. 1, the cutting device 1 of this embodiment includes a cleaning nozzle 61 that sprays a cleaning fluid toward the wafer W, and a nozzle moving mechanism 62 that moves the cleaning nozzle 61 in the Y-axis direction. The cleaning nozzle 61 is supported at the tip of an arm 63 that extends in the Y-axis direction. A cleaning fluid is supplied to the cleaning nozzle 61 from a fluid supply source 64.

[0025] The cleaning nozzle 61 sprays a fluid toward the wafer W supported by the chuck table 21 disposed below. More specifically, the cleaning nozzle 61 sprays a fluid toward one groove M in the wafer W supported by the chuck table 21 to clean the bottom surface of the groove M. Various fluids can be used as the fluid as long as they can clean the bottom surface of the groove M, and examples of the fluid include high-pressure water, two-fluid fluid, ultrasonic water, and micro ice jet.

[0026] When high-pressure water is used as the cleaning fluid, the pressure is preferably set in the range of about 3 MPa to 15 MPa, and more preferably, about 5 MPa to 8 MPa.

[0027] When using a two-fluid mixture of cleaning water and high-pressure air as the cleaning fluid, it is preferable that the pressure of the high-pressure air is set to 0.4 to 0.6 MPa and the amount of cleaning water is set to 100 to 500 ml / min, and it is more preferable that the amount of cleaning water is set to 200 ml / min.

[0028] When ultrasonic water is used as the cleaning fluid, the frequency applied is in the range of 500 KHz to 5 MHz. Although a lower frequency increases the cleaning power, it may cause stress to the devices on the wafer W, so a frequency of around 1 MHz is preferable.

[0029] An example of an ice jet used as a cleaning fluid is one that jets ice particles (supercooled water droplets) having a particle size of about 10 um to 30 um, which are generated by accelerating cleaning water to supersonic speed with high-pressure air.

[0030] When high-pressure air is used as the cleaning fluid, the air pressure is increased in at least one of the fluid supply source 64 and the cleaning nozzle 61. When both cleaning water and high-pressure air are used as the cleaning fluid, a fluid supply source 64 for the cleaning water and a fluid supply source 64 for the high-pressure air may be provided and mixed in the cleaning nozzle 61.

[0031] The nozzle moving mechanism 62 is provided on the rear surface of the Z-axis table 45, and employs an appropriate structure using a cylinder, motor, slider, ball screw, or the like that supports the base of the arm 63 and moves the arm 63 in the Y-axis direction. Through the arm 63 and the nozzle moving mechanism 62, the cleaning nozzle 61 is disposed on the -X side (downstream in the cutting direction) of the cutting blade 54. By driving the nozzle moving mechanism 62, the cleaning nozzle 61 can be moved in the Y-axis direction through the arm 63.

[0032] The cutting device 1 is provided with a control unit 70 that controls each unit of the device (see FIG. 1). The control unit 70 is composed of a processor that executes various processes, a memory, etc. The control unit 70 controls various operations such as forming a groove M on the surface of the wafer W, driving the nozzle moving mechanism 62, and spraying a fluid from the cleaning nozzle 61 according to a control program stored in the memory.

[0033] Here, the control unit 70 is provided with an index amount setting unit 71. The index amount setting unit 71 sets an index amount D (see FIG. 4A) in the Y-axis direction which is the distance between the streets L of the wafer W held on the chuck table 21. Examples of setting the index amount D include reading or calculating from various data of the wafer W pre-stored in a storage unit such as a memory in the control unit 70, or measuring based on image data of the surface of the wafer W captured by an imaging device (not shown).

[0034] In addition, in the operation of each part of the cutting device 1 described below, unless a control entity is specified, it is assumed that the operation is controlled by a control signal sent from the control unit 70.

[0035] Next, a method for forming grooves M for dividing the wafer W by the cutting device 1 will be described.

[0036] In forming the grooves M in the wafer W, first, the wafer W is transferred onto the chuck table 21 with its front surface facing upward. Then, after the wafer W is placed within the plane of the holding surface 211 of the chuck table 21, the holding surface 211 is connected to a suction source 212 (see FIGS. 2 and 3 ) and the wafer W is held by suction on the chuck table 21.

[0037] After completing this holding, as shown in Fig. 4A, the grid-like streets L on the wafer W held on the chuck table 21 are aligned parallel to the X-axis direction and the Y-axis direction by driving the rotation mechanism 22. Next, the Y-axis table 35 is moved to position the cutting blade 54 of the cutting mechanism 51 on the street L located on the +Y side of the wafer W in the Y-axis direction. Next, the Z-axis table 45 is moved to position the lower end of the cutting blade 54 according to the depth of the groove M to be formed in the wafer W. In this positioning, the bottom surface of the groove M is set to leave a predetermined thickness from the rear surface of the wafer W so that the groove M becomes a half-cut groove.

[0038] After the cutting blade 54 is positioned by the Z-axis table 45, the chuck table 21 is moved relative to the cutting blade 54 rotated at high speed via the X-axis moving mechanism 15. As a result, the wafer W is cut by the rotating cutting blade 54, and grooves M are formed along the streets L of the wafer W. Each time one groove M is formed, the Y-axis table 35 is moved by an index amount D in the Y-axis direction of the street L, and after the grooves M are formed on all the streets L parallel to the X-axis, the rotation mechanism 22 is rotated 90°. Then, among the lattice-shaped streets L, the streets L on which the grooves M are not yet formed are made parallel to the X-axis. From this state, the grooves M are formed on all the streets L parallel to the X-axis in the same manner as described above, and the grooves M are formed on all the lattice-shaped streets L.

[0039] After the grooves M are formed on all of the streets L, a tape (not shown) is attached to the front surface of the wafer W, and the back surface of the wafer W is ground to divide the wafer W into multiple chips with the formation positions of the grooves M as the outer periphery.

[0040] Here, in the cutting device 1 of this embodiment, the bottom surface of the groove M is cleaned using a cleaning nozzle 61 or the like at the same time as cutting with the cutting blade 54 that forms the groove M. Hereinafter, a method for cleaning the groove M that is performed at the same time as the cutting will be described with reference to Figures 4B and 4C. Figures 4B and 4C are plan views similar to Figure 4A during the cutting and cleaning of the groove.

[0041] 4B , while the cutting blade 54 is forming a groove M along the street L of the wafer W, the nozzle moving mechanism 62 moves and positions the cleaning nozzle 61 so that it is located on the +Y side of the cutting blade 54. Specifically, the cleaning nozzle 61 is positioned above the groove M, which is one index amount D away on the +Y side from the street L on which the cutting process is progressing by the cutting blade 54.

[0042] Such positioning is performed by the control unit 70 controlling the driving of the nozzle movement mechanism 62 based on the value of the index amount D set and output by the index amount setting unit 71. As a result, fluid can be sprayed from the cleaning nozzle 61 toward the bottom surface of the groove M that is adjacent to the +Y side of the street L during cutting of the groove M by the cutting blade 54 and has been cut, and cutting chips adhering to the bottom surface of the groove M can be washed away.

[0043] Here, the distance between the street L where the cutting of the groove M is progressing with the cutting blade 54 and the groove M to which the fluid is sprayed from the cleaning nozzle 61 is not limited to one index amount D. For example, as shown in Fig. 4C, this distance may be set to two index amounts D, or the index amount D may be set to two or more (at least one).

[0044] According to the above embodiment, even if cutting chips adhere to the bottom surface of the groove M formed by cutting processing, the adhering cutting chips can be removed by the fluid sprayed from the cleaning nozzle 61 after the groove M is processed and during the next or subsequent processing of the groove M.

[0045] Here, as a comparative structure, a structure will be considered in which the position of the washing nozzle in the Y-axis direction is the same as that of the cutting blade 54, but the nozzle is located away from the cutting blade 54 on the -X side. In such a comparative structure, the cutting water is scattered on the -X side due to the rotation of the cutting blade 54, and the pressure of the washing water sprayed toward the groove M decreases. For this reason, in the comparative structure, it becomes difficult to remove the cutting chips adhering to the bottom surface of the groove M. Furthermore, if the sprayed washing water is made high-pressure, the amount of cutting chips removed can be increased, but the amount of washing water sprayed increases.

[0046] In this regard, in the above embodiment, the fluid is sprayed onto the bottom surface of the groove M that is at least one street L (groove M) away from the +Y side by the index amount D during machining, and the spray of the fluid can be made less susceptible to the influence of the scattering cutting water. This makes it possible to maintain the cleaning effect of the groove M without increasing the pressure of the fluid sprayed from the cleaning nozzle 61, and to avoid an increase in the amount of fluid sprayed. In this way, in the above embodiment, the amount of fluid sprayed is suppressed, and the cleaning fluid can be sprayed onto one groove M without being hindered by the cutting water scattered by the rotation of the cutting blade 54, and cutting chips attached to the bottom surface of the groove M can be efficiently removed.

[0047] Furthermore, since the cleaning nozzle 61 is moved in the Y-axis direction by the nozzle moving mechanism 62, the groove M to be cleaned by the cleaning nozzle 61 can be selected as shown in Figures 4B and 4C. Also, since the control unit 70 controls the nozzle moving mechanism 62 according to the index amount D set by the index amount setting unit 71, it is possible to easily accommodate various wafers W having different index amounts D, thereby enhancing versatility.

[0048] The present invention is not limited to the above-described embodiment, and can be modified in various ways. In the above-described embodiment, the size and shape shown in the attached drawings are not limited to these, and can be modified as appropriate within the scope of the effects of the present invention. In addition, the present invention can be modified as appropriate without departing from the scope of the object of the present invention.

[0049] For example, in the above embodiment, the nozzle moving mechanism 62 is provided on the rear surface of the Z-axis table 45, but this is not limited to this and various modifications are possible, for example, by disposing it on the spindle housing 52 or the blade cover 55.

[0050] In the above embodiment, the workpiece is a wafer W, but may be a package substrate P as shown in FIG. 5. The package substrate P in FIG. 5 includes a rectangular resin substrate P1 and a plurality of resin protrusions P2 (three in FIG. 5) arranged in a line in the longitudinal direction on the surface of the resin substrate P1. The resin substrate P1 is, for example, a PCB substrate. The package substrate P is divided into a plurality of device regions A1 for semiconductor devices in which a plurality of protrusions P2 are arranged and electrodes are provided therein, and a surplus region A2 around the device region A1. Each device region A1 is divided into a plurality of regions by lattice-shaped streets L, and a semiconductor device (not shown) is provided in each region.

[0051] 5, as in the above embodiment, when cutting groove M with cutting blade 54 of cutting mechanism 51, fluid can be sprayed from cleaning nozzle 61 to groove M in front of (on the +Y side of) street L being cut. When processing package substrate P in FIG. 5, holding surface 211 of chuck table 21 is formed into a rectangular shape in accordance with resin substrate P1.

[0052] In the embodiment described above, the groove M is formed by so-called down-cutting, in which the cutting blade 54 is rotated in the same direction as the cutting direction of the chuck table 21, but the present invention is not limited to this configuration. The groove M may be formed by up-cutting, in which the cutting blade 54 is rotated in the opposite direction to the cutting direction of the chuck table 21. [Industrial Applicability]

[0053] As described above, the present invention has the effect of efficiently removing cutting chips adhering to the bottom surface of the groove when cutting is performed by rotating a cutting blade while washing away the cutting chips with cutting water. [Explanation of symbols]

[0054] 1:Cutting device 15:X-axis movement mechanism 21: Chuck table 211: Holding surface 31:Y-axis movement mechanism 51: Cutting mechanism 54: Cutting blade 61: Cleaning nozzle 62: Nozzle movement mechanism 64 :Fluid supply source 70: Control section 71: Index amount setting section D: Index amount L: Street M:Groove W: Wafer

Claims

[Claim 1] a cutting device comprising: a chuck table that holds a wafer having lattice-like streets by a holding surface; an X-axis movement mechanism that moves the chuck table in an X-axis direction which is a cutting direction of a cutting blade; a cutting mechanism that cuts the wafer held on the chuck table with the cutting blade to form grooves in the wafer; a Y-axis movement mechanism that moves the cutting mechanism in a Y-axis direction parallel to the holding surface and perpendicular to the X-axis direction; and a cleaning nozzle that sprays a fluid toward a bottom surface of the groove to clean the bottom surface, a nozzle moving mechanism that moves the cleaning nozzle in the Y-axis direction; and an index amount setting unit that sets an index amount in the Y-axis direction, which is an interval between streets of a wafer held on the chuck table. a control unit that controls the positioning of the cleaning nozzle so that fluid is sprayed onto a bottom surface of one of the grooves that is at least one index amount before the street being cut by the cutting blade, based on the value of the index amount setting unit and the nozzle moving mechanism.

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