Kerf cleaning device

Abstract

To provide a cleaning device suitable for cleaning kerfs formed on semiconductor wafers.SOLUTION: One embodiment is a cleaning device 1 that cleans kerfs formed along the streets when a wafer W having a plurality of devices defined by streets on its surface is diced. The cleaning device 1 includes a holder 10 that holds the wafer W, a cleaning nozzle 34 that discharges a jet of cleaning liquid toward the kerf, and a movement mechanism that moves the cleaning nozzle 34 and the holder 10 relative to each other to move the liquid jet in the longitudinal direction of the kerf. The discharge opening of the cleaning nozzle 34 has a diameter that is substantially the same as or less than the width of the street.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus for cleaning kerfs formed in a wafer by dicing. [Background technology]

[0002] Wafers on which numerous devices have been formed in the pre-processing of semiconductor manufacturing are divided into multiple chips for each device in the dicing process. Multiple devices are formed on the front surface of the wafer, and each device is separated by planned separation lines called streets. To prevent the chips from falling apart, adhesive tape (hereafter also referred to as "dicing tape") is attached to the back surface of the wafer prior to dicing. In the dicing process, cuts are made along the streets from the front side of the wafer, separating the devices.

[0003] Dicing methods include blade dicing, which cuts the wafer by pressing a dicing blade against it, and laser dicing, which separates the wafer surface using a laser. Regardless of which method is used, kerfs (cut grooves) are formed on the wafer surface by dicing within the streets.

[0004] Debris generated during dicing can adhere to the walls of the kerf. Furthermore, because the edge of the kerf is brittle, a layer that is about to peel off can form, and the peeled pieces from the edge become new debris. If this debris adheres to the device, it may cause defects in subsequent processes (such as wire bonding). In response to this issue, technologies have been proposed for cleaning wafers after processing to remove debris (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-90237 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-60284 Summary of the Invention [Problem to be solved by the invention]

[0006] The cleaning device in Patent Document 1 removes debris remaining in the kerf using so-called spin cleaning. A diced wafer is held on a spinner table, and the spinner table is rotated forward and backward while a cleaning solution is supplied diagonally from above toward the side of the kerf. This allows the cleaning solution to hit both side walls of the kerf, washing away the debris. Debris adhering to the kerf is scattered along with the cleaning solution by centrifugal force and discharged to the outside. However, because spin cleaning generally supplies the cleaning solution at low pressure, it may not be possible to fully remove the debris depending on the degree of adhesion. The center of the wafer, in particular, rotates slowly, making it difficult to achieve sufficient cleaning power. While increasing the rotation speed of the spinner table is an option, increasing the rotation speed too much can result in unstable wafer retention.

[0007] On the other hand, the cleaning equipment in Patent Document 2 is used to clean substrate surfaces in the pre-processing stage of semiconductor manufacturing. After dry etching, the cleaning solution is sprayed obliquely along the wiring grooves to remove foreign matter. Because the cleaning solution is sprayed evenly across the entire surface of the substrate, the spray pressure is not very high, but it is believed to be sufficient to remove foreign matter (such as resist residue) after dry etching. Meanwhile, during dicing, melted debris can become solidified. Therefore, even if this cleaning equipment is used for kerf cleaning, the liquid pressure is low enough to remove the debris within the kerf, making it difficult to achieve a sufficient cleaning effect. While it is possible to address this issue by increasing the spray pressure of the cleaning solution, this would result in the high-pressure cleaning solution reaching the inside of the chip, potentially damaging the device.

[0008] The present invention has been made in view of the above circumstances, and one of its objects is to provide a cleaning apparatus suitable for cleaning kerfs formed on semiconductor wafers. [Means for solving the problem]

[0009] One aspect of the present invention is a kerf cleaning apparatus for cleaning kerfs formed along the streets when a wafer having a plurality of devices defined by streets on its surface is diced. The cleaning apparatus includes a holder for holding the wafer, a cleaning nozzle for discharging a cleaning liquid jet toward the kerf, and a movement mechanism for moving the cleaning nozzle and the holder relative to each other to move the liquid jet in the longitudinal direction of the kerf. The cleaning nozzle outlet has a diameter that is substantially the same as or smaller than the width of the street. [Effects of the Invention]

[0010] According to the present invention, a cleaning apparatus suitable for cleaning kerfs formed on semiconductor wafers can be provided. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating a schematic configuration of a cleaning device according to a first embodiment. [Figure 2] FIG. 1 is a diagram schematically illustrating a system configuration of a cleaning device. [Figure 3] FIG. 2 is a diagram schematically illustrating the configuration of a cleaning liquid supply unit and a gas supply unit. [Figure 4] FIG. 2 is a perspective view showing the structure of a wafer after dicing. [Figure 5] FIG. 2 is a plan view of a wafer. [Figure 6] 1A and 1B are diagrams showing variations in dicing processing and cross-sectional structures of kerfs. [Figure 7] FIG. 1 is a diagram illustrating a method for cleaning a kerf. [Figure 8] FIG. 1 is a diagram illustrating a method for cleaning a kerf. [Figure 9] FIG. 10 is a diagram schematically illustrating the configuration of a cleaning device according to a second embodiment. [Figure 10] FIG. 1 is a diagram schematically illustrating a system configuration including a fine bubble mixing section. [Figure 11]FIG. 10 is a diagram schematically illustrating the configuration of a cleaning device according to a third embodiment. [Figure 12] FIG. 2 is a diagram schematically illustrating a system configuration including a cleaning unit. [Figure 13] FIG. 2 is a diagram schematically illustrating the configuration of a cleaning unit. [Figure 14] FIG. 10 is a diagram schematically illustrating the configuration of a cleaning device according to a modified example. [Figure 15] 10A and 10B are diagrams illustrating a usage mode of a cleaning device according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiment and its modifications, substantially the same components are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

[0013] [First embodiment] The cleaning apparatus of this embodiment cleans the surface of a semiconductor wafer (also simply referred to as a "wafer") after dicing and removes debris adhering to the kerf. As described above, since the width of the kerf is small, on the microscale, the cleaning liquid is supplied in the form of a liquid jet, which allows the cleaning liquid to spread throughout the kerf. By setting the diameter of the cleaning nozzle outlet to be smaller than the width of the street, the position where the liquid jet hits is limited to within the street, preventing damage to devices on the surface of the wafer. In other words, this embodiment is devised to ensure the cleaning strength required for kerf cleaning while protecting the devices on the wafer. The details of this are described below.

[0014] FIG. 1 is a diagram showing a schematic configuration of a cleaning device according to a first embodiment. For convenience of explanation, the following description will be given assuming that the front-rear direction, left-right direction, and up-down direction when viewing the cleaning apparatus from the front are the X direction, Y direction, and Z direction, respectively. The cleaning device 1 includes a workpiece holder 10 that holds a wafer W, and a cleaning head 20 that ejects a jet of cleaning liquid toward the wafer W.

[0015] The wafer W has undergone a dicing process, resulting in the formation of kerfs on its surface. In addition to the blade dicing and laser dicing mentioned above, other dicing methods include plasma dicing. The plasma dicing method separates the wafer into chips by dry etching using plasma. Laser dicing methods include the laser ablation method, which separates the wafer by sublimating and evaporating it with a laser, and the laser internal processing method, which forms a modified layer inside the wafer with a laser and then separates it using tension (for example, the technology described in Japanese Patent No. 3408805). The cleaning apparatus 1 can be applied to wafers with kerfs on their surface, regardless of the dicing method used.

[0016] The workpiece holding unit 10 includes a work table 12, a rotary table 14, an X table 16, and a Y table 18. The work table 12 has a holding surface 12a that holds the wafer W by suction. The holding surface 12a is provided with a plurality of suction holes through which a vacuum is drawn to hold the back surface of the wafer W by suction. By driving a vacuum suction source (not shown), the wafer W can be sucked and fixed to the holding surface 12a.

[0017] A pair of guide rails 22 extending in the Y direction are provided on the base 2 of the cleaning apparatus 1. The Y table 18 is installed horizontally so that it can move in the Y direction along the guide rails 22. The Y table 18 is driven by a Y movement mechanism 24. A pair of guide rails 26 extending in the X direction are provided on the upper surface of the Y table 18. The X table 16 is installed horizontally so that it can move in the X direction along the guide rails 26. The X table 16 is driven by an X movement mechanism 28. In this embodiment, each movement mechanism is realized by a linear motor, but may also be realized by a screw feed mechanism and a servo motor that drives it.

[0018] The rotary table 14 is rotatably supported by the X-table 16, and the work table 12 is fixed to the upper surface of the rotary table 14. The rotary table 14 can be rotated around its own axis (in the θ direction around an axis L extending in the Z direction) by a rotation mechanism 30. The rotation mechanism 30 is realized by, for example, a spindle motor. With this configuration, the work table 12 can move in each of the X direction, Y direction, and θ direction.

[0019] Meanwhile, a Z table 32 is disposed on a column 4 erected on the base 2, and the cleaning head 20 is supported by the Z table 32. The cleaning head 20 includes a cleaning nozzle 34 that ejects the cleaning liquid toward the wafer W in the form of a liquid jet.

[0020] A pair of guide rails 36 extending in the Z direction are provided on the front surface of the column 4. The Z table 32 is installed so as to be movable in the Z direction along the guide rails 36. The Z table 32 is driven by a Z movement mechanism 38. The Z movement mechanism 38 is realized, for example, by a screw feed mechanism and a servo motor that drives it. The Z table 32 is provided with an angle adjustment mechanism 37 that can adjust the inclination angle of the cleaning nozzle 34 with respect to the surface of the wafer W (described in detail later).

[0021] In the above configuration, the X-moving mechanism 28, the Y-moving mechanism 24, the Z-moving mechanism 38, and the rotation mechanism 30 function as a "moving mechanism" that moves the cleaning head 20 (i.e., the cleaning nozzle 34) and the work table 12 (i.e., the wafer W) relative to each other.

[0022] FIG. 2 is a diagram schematically illustrating the system configuration of the cleaning device 1. As shown in FIG. In addition to the workpiece holder 10 and cleaning head 20 described above, the cleaning device 1 also includes a cleaning liquid supply unit 40, a gas supply unit 42, and a control unit 50. The cleaning liquid supply unit 40 is connected to the cleaning head 20 via a liquid supply path 41, and supplies a pressurized cleaning liquid (e.g., pressurized water) to the cleaning head 20. The gas supply unit 42 is connected to the cleaning head 20 via a gas supply path 43, and supplies a gas to the cleaning head 20 to stabilize the liquid jet LJ. The control unit 50 controls the cleaning liquid supply unit 40, the gas supply unit 42, and the movement mechanism described above.

[0023] FIG. 3 is a diagram schematically illustrating the configuration of the cleaning liquid supply unit 40 and the gas supply unit 42. As shown in FIG. The cleaning liquid supply unit 40 includes a liquid supply source 44, a pump 46, and a flow control valve 48. The pump 46 and the flow control valve 48 are provided, from upstream, on a liquid supply path 41 that connects the liquid supply source 44 and the cleaning head 20. The liquid supply source 44 has a tank that stores cleaning liquid. The cleaning liquid can be drawn up from the liquid supply source 44 by driving the pump 46 and supplied to the cleaning head 20. Pressurized cleaning liquid is supplied to the cleaning head 20. The flow control valve 48 controls the flow rate of the cleaning liquid supplied to the cleaning head 20. In this embodiment, the flow control valve 48 is a motor-driven electric valve, but it may also be a solenoid-driven electromagnetic valve.

[0024] The gas supply unit 42 includes a gas supply source 52 and an on-off valve 54. The on-off valve 54 is provided in a gas supply path 43 that connects the gas supply source 52 and the cleaning head 20. The gas supply source 52 has a tank that stores pressurized gas. The on-off valve 54 is an electromagnetic valve, and gas can be supplied from the gas supply path 43 to the cleaning head 20 by opening the on-off valve 54.

[0025] Returning to FIG. 2, the cleaning head 20 includes a cleaning nozzle 34 and an air nozzle 35. The cleaning nozzle 34 discharges the cleaning liquid supplied from the cleaning liquid supply unit 40 as a liquid jet LJ. The air nozzle 35 is provided coaxially downstream of the cleaning nozzle 34. A chamber 60 is formed between the cleaning nozzle 34 and the air nozzle 35. An inlet port 62 communicating with the chamber 60 is provided in the side wall of the cleaning head 20, and a gas supply path 43 is connected to the inlet port 62.

[0026] The gas introduced from the inlet port 62 is guided to the air nozzle 35 while swirling around the liquid jet LJ, and is then discharged from the air nozzle 35 as a gas jet GJ. This gas flow (swirling flow) acts as a guide wall to suppress the spread of the liquid jet LJ. In other words, the liquid jet LJ travels straight without diffusing. Therefore, the diameter of the liquid jet LJ that strikes the wafer W is approximately equal to the diameter of the discharge port 34a of the cleaning nozzle 34.

[0027] The air nozzle 35 discharges the gas jet GJ so as to surround the liquid jet LJ. By coaxially surrounding the liquid jet LJ with the gas jet GJ, the liquid jet LJ can be stably discharged in a straight line. The diameter of the liquid jet LJ discharged from the cleaning nozzle 34 toward the wafer W can be kept almost constant. This can be achieved, for example, by using the technology described in Japanese Patent No. 5437578.

[0028] The control unit 50 is a general-purpose computer and includes a CPU for executing various arithmetic processes, memory or storage for storing control programs, etc., memory used as a work area for storing data and executing programs, an input / output interface, etc. The control unit 50 controls the operation of the cleaning liquid supply unit 40, the gas supply unit 42, and each moving mechanism in accordance with the control program. Note that, although the control unit 50 controls each unit of the cleaning apparatus in this embodiment, each unit may be provided with its own control unit.

[0029] Next, the kerf cleaning method according to this embodiment will be described in detail. FIG. 4 is a perspective view showing the structure of the wafer W after dicing. The wafer W undergoes a dicing process, forming grid-like kerfs K (kerfs) surrounding each of the devices D. A dicing tape 70 is attached to the back surface of the wafer W, and the peripheral edge of the dicing tape 70 is fixed to an annular frame 72. The wafer W is fixed to the work table 12 via the frame 72 (see FIG. 1).

[0030] FIG. 5 is a plan view of the wafer W. FIG. 5(A) shows the wafer before dicing, and FIG. 5(B) shows the wafer after dicing. FIG. 5(C) is an enlarged view of part A in FIG. 5(B). Note that this is a schematic diagram for ease of understanding, and chips and other components provided on the wafer W are depicted larger than they actually are.

[0031] As shown in Figure 5(A), streets S1 and S2 that are perpendicular to each other are set as planned dividing lines on the surface of the wafer W. Street S1 extends in the X direction, and street S2 extends in the Y direction. A plurality of these streets S1 and S2 are set on the surface of the wafer W and arranged in a grid pattern. Devices D are formed within areas defined by these streets S1 and S2.

[0032] 5(B), dicing is performed along these streets S1 and S2, and a kerf K is formed so as to pass through the center of each street S1 and S2 in the width direction. In this embodiment, the widths of the streets S1 and S2 are the same, and therefore, when there is no need to distinguish between them, they are collectively referred to as "street S."

[0033] As shown in FIG. 5C, the street S is a boundary that separates adjacent devices D, and the kerf K is formed within the range of the street S. In this embodiment, the width of the kerf K (kerf width Wk) is several tens of μm, which is smaller than the width of the street S (street width Ws). Because the kerf width Wk is extremely small, it is necessary to increase the cleaning strength (liquid pressure) in order to spread the cleaning liquid throughout the kerf K.

[0034] On the other hand, if the high-pressure cleaning liquid hits the device D, it may damage the device D. Therefore, in this embodiment, the diameter of the liquid jet discharged toward the kerf K is set to be approximately the same as the kerf width Wk, or at least smaller than the street width Ws. Note that the diameter of the liquid jet may also be smaller than the kerf width Wk (details will be described later).

[0035] FIG. 6 shows variations in dicing processing and the cross-sectional structure of the kerf. There are several types of dicing processes, including full-cut, half-cut, and grooving. As shown in Figure 6(A), in full-cut, the dicing depth reaches the entire height of the wafer W. This means that the kerf K reaches the dicing tape 70, but the dicing tape 70 is not cut and the chips do not separate.

[0036] As shown in Figure 6(B), in half-cut processing, the dicing depth does not reach the entire height of the wafer W. For this reason, a subsequent grinding process is required to simultaneously thin the wafer and separate it into chips, or a laser internal processing and expanding process, or a full-cut process using blade dicing. As shown in Figure 6(C), grooving processing cuts only the wiring layer of the wafer W under conditions optimized for cutting the wiring layer, and a subsequent laser internal processing and expanding process, or a full-cut process using blade dicing, is required. Regardless of the dicing process, a kerf K is formed. These kerfs K are the target for cleaning.

[0037] 7 and 8 are diagrams schematically illustrating a kerf cleaning method. Fig. 7(A) shows a method for controlling the movement mechanism in the cleaning apparatus 1. Fig. 7(B) is an enlarged view of part B in Fig. 7(A). The outline arrow in the figure indicates the relative movement direction of the cleaning nozzle 34 with respect to the wafer W.

[0038] 7(A), in the kerf cleaning process, the control unit 50 controls the driving of the cleaning liquid supply unit 40, the gas supply unit 42, and each moving mechanism to perform jet cleaning along the kerf K. By driving the X moving mechanism 28 to move the cleaning nozzle 34 and the wafer W relatively in the X direction, the liquid jet LJ can be moved in the longitudinal direction of the kerf K. At this time, the liquid jet LJ is discharged while the cleaning nozzle 34 (cleaning head 20) is moved relative to the wafer W along a vertical plane Fv including the kerf K.

[0039] As shown in FIG. 7(B), the width Wk and depth h of the kerf K are several tens of μm, but fine debris d adheres to the inner wall surface of the kerf K immediately after dicing. Also, peeled pieces f may occur at the edge of the kerf K. The liquid jet LJ has a liquid pressure sufficient to wash away these debris. In this embodiment, the diameter of the discharge port 34a of the cleaning nozzle 34 is set to several tens of μm, which is approximately the same as the kerf width Wk. Furthermore, the liquid pressure (discharge pressure) of the liquid jet LJ is set sufficiently high, for example, in the range of 100 to 600 bar. Therefore, the liquid pressure acting on the position where the liquid jet LJ hits is also approximately the same, allowing the liquid jet LJ to be sufficiently distributed within the kerf K.

[0040] 8(A) is a cross-sectional view taken along the vertical plane Fv in FIG. 7(A), and FIG. 8(B) is a view seen in the direction of the arrow C in FIG. 8(A). 8(A), the cleaning nozzle 34 (more specifically, the axis L1 of the discharge port 34a) is set to form a predetermined inclination angle θ1 (e.g., 45 degrees) with respect to the surface of the wafer W. The cleaning apparatus 1 is equipped with the angle adjustment mechanism 37 described above (see FIG. 1), and can appropriately adjust the inclination angle θ1 of the cleaning nozzle 34 with respect to the surface of the wafer W (i.e., the discharge angle of the liquid jet LJ with respect to the surface of the wafer W).

[0041] In this embodiment, the angle adjustment mechanism 37 includes a goniostage (not shown) or the like, and can manually adjust the angle of the cleaning head 20 relative to the work table 12. In a modified example, the angle adjustment mechanism 37 may include a stepping motor that rotates the cleaning head 20 about a horizontal axis. The control unit 50 may control the motor to automatically adjust the angle.

[0042] The cleaning nozzle 34 discharges the liquid jet LJ obliquely downward toward the front of the wafer W in the direction of travel relative to the wafer W. This allows the cleaning liquid discharged earlier to be expelled from the kerf K by pushing it forward together with debris. As shown in FIG. 8(B), cleaning is performed efficiently with the liquid jet LJ contained within the kerf K. After cleaning the kerf K along the street S1, the rotation mechanism 30 rotates the work table 12 by 90 degrees, allowing the kerf K along the street S2 to be cleaned (see FIG. 5(B)).

[0043] Regarding the tilt angle θ1, a correspondence relationship that provides good cleaning performance may be set in advance based on experiments or the like between cleaning conditions such as the discharge pressure and discharge flow rate of the liquid jet LJ and the tilt angle of the cleaning nozzle 34 relative to the wafer W. Other cleaning conditions may include the type of dicing, the presence or absence of a liquid film (third embodiment) described later, and the like.

[0044] As described above, in this embodiment, the diameter of the discharge port 34a of the cleaning nozzle 34 is set to be equal to or smaller than the kerf width Wk, so that the diameter of the liquid jet LJ can be made approximately the same as the kerf width Wk. This makes it easy to achieve jet cleaning that is targeted at the kerf K. Since the liquid jet LJ is prevented from directly hitting the device D, the liquid pressure can be set high. This ensures sufficient cleaning strength required for kerf cleaning, thereby improving cleaning efficiency.

[0045] In particular, when using the laser ablation method, burrs are generated on the edge of the formed kerf, so a high cleaning effect can be achieved by setting the diameter of the liquid jet LJ to be equal to or larger than the kerf width Wk and equal to or smaller than the street width Ws. However, by scanning the liquid jet LJ by shifting the injection position in the Y direction from the center of the kerf, it is possible to remove burrs even if the diameter of the liquid jet LJ is smaller than the kerf width Wk.

[0046] [Second embodiment] The cleaning device of this embodiment differs from the first embodiment in that fine bubbles (microscopic air bubbles) are mixed into the liquid jet discharged from the cleaning nozzle. FIG. 9 is a diagram schematically illustrating the configuration of a cleaning device according to the second embodiment. In the cleaning device 201, the cleaning liquid supply unit 240 includes a fine bubble mixing unit 210. The fine bubble mixing unit 210 mixes microbubbles or nanobubbles into the cleaning liquid upstream of the cleaning nozzle 34. Hereinafter, microbubbles or nanobubbles will be collectively referred to as "fine bubbles" as appropriate.

[0047] FIG. 10 is a diagram showing a schematic diagram of a system configuration including the fine bubble mixing section 210. In this embodiment, a branch path 45 is provided that branches off from the gas supply path 43. The branch path 45 is connected to the liquid supply path 41 on the upstream side of the cleaning head 20. That is, the gas from the gas supply source 52 is also supplied to the liquid supply path 41 via the branch path 45.

[0048] The fine bubble mixing section 210 generates fine bubbles by injection, and includes, from the upstream side of the branching path 45, a pressure booster valve 212, a pressure booster tank 214, a flow control valve 216, and an injector 218. A portion of the gas supplied from the gas supply source 52 is boosted in pressure by the pressure booster valve 212 and stored in the pressure booster tank 214. The supply amount of the boosted gas is controlled by adjusting the aperture of the flow control valve 216. In this embodiment, the flow control valve 216 is an electrically operated valve, but it may also be an electromagnetic valve.

[0049] The pressurized gas is injected from the nozzle of the injector 218 into the liquid supply path 41 and mixed into the cleaning liquid as fine bubbles. More specifically, by injecting pressurized gas into the pressurized cleaning liquid, a gas-liquid mixed flow containing microbubbles or nanobubbles is generated. Each part of the fine bubble mixing unit 210 is controlled by the control unit 50. The control unit 50 controls the flow control valve 48 and the flow control valve 216, respectively, to adjust whether or not fine bubbles are mixed into the cleaning liquid and the amount of fine bubbles to be mixed in.

[0050] In addition to the injection method, there are various other methods for generating fine bubbles in the cleaning liquid, such as the cavitation method, in which gas is sucked into a swirling flow of pressurized cleaning liquid and pulverized to generate fine bubbles; the gas-liquid agitation method, in which gas is supplied to the pressurized cleaning liquid while being agitated at high speed to break down the air bubbles present in the cleaning liquid and generate fine bubbles; and the gas dispersion method, in which fine bubbles are generated by passing gas through a porous body immersed in the cleaning liquid (see, for example, JP 2008-253893 A). Any of these methods may be used, but the fine bubbles to be mixed in should have a diameter sufficiently smaller than that of the liquid jet LJ, that is, sufficiently smaller (several tens of μm or less) than the diameter of the discharge hole 34a.

[0051] 9, the control unit 50 can mix fine bubbles into the cleaning liquid and discharge the mixed liquid as a liquid jet LJ from the cleaning nozzle 34 by operating the fine bubble mixing unit 210. According to this embodiment, the fine bubbles in the cleaning liquid can adsorb debris and wash it away, thereby further improving the cleaning efficiency of the calf K.

[0052] [Third embodiment] The cleaning apparatus of this embodiment differs from the first embodiment in that a liquid film is formed on the surface of the wafer W and a liquid jet LJ is supplied from above the liquid film. FIG. 11 is a diagram schematically illustrating the configuration of a cleaning device according to the third embodiment. The cleaning apparatus 301 includes a cleaning unit 310 that supplies a cleaning liquid so that a liquid film Lm is formed on the surface of the wafer W, in addition to the jet cleaning performed by the cleaning head 20. The cleaning head 20 functions as a "first cleaning unit," and the cleaning unit 310 functions as a "second cleaning unit."

[0053] In this embodiment, the cleaning unit 310 is provided integrally with the work table 12, but in a modified example, it may be provided as a cleaning device independent of the workpiece holder 10. A liquid supply path 47 is provided that connects the cleaning liquid supply unit 40 and the cleaning unit 310, and cleaning liquid is supplied from the cleaning liquid supply unit 40 to the cleaning unit 310. Low-pressure cleaning liquid is supplied from the cleaning unit 310 in the form of a sprinkler, rather than a liquid jet.

[0054] FIG. 12 is a diagram showing a schematic diagram of a system configuration including the cleaning unit 310. As shown in FIG. A liquid supply path 47 is provided so as to branch off from the liquid supply path 41 downstream of the pump 46, and is connected to the cleaning unit 310. A flow control valve 312 is provided in the liquid supply path 47. The cleaning liquid is also supplied to the liquid supply path 47 when the pump 46 is driven. The flow control valve 312 controls the flow rate of the cleaning liquid supplied to the cleaning unit 310. In this embodiment, the flow control valve 312 is an electric valve, but it may also be an electromagnetic valve.

[0055] FIG. 13 is a diagram showing a schematic configuration of the cleaning unit 310. As shown in FIG. The cleaning section 310 has a block 320 fixed to the work table 12 and a nozzle unit 322 attached to the block 320. The nozzle unit 322 includes a chamber 324 that communicates with the liquid supply path 47 and a plurality of liquid supply holes 326 that communicate with the chamber 324. The nozzle unit 322 has an arc-shaped side surface facing the wafer W, and a plurality of liquid supply holes 326 are arranged on the side surface. All of the liquid supply holes 326 open toward the wafer W side.

[0056] The cleaning liquid supplied through the liquid supply path 47 is stored in the chamber 324 and is discharged from each liquid supply hole 326 toward the surface of the wafer W. This cleaning liquid flows over the surface of the wafer W in a direction away from the cleaning nozzle 34 while forming a liquid film on the surface of the wafer W, and is led to a drainage path (not shown). That is, on the surface of the wafer W, the flow direction of the cleaning liquid discharged from the cleaning nozzle 34 and the flow direction of the cleaning liquid discharged from the nozzle unit 322 are the same.

[0057] According to this embodiment, by forming a thin liquid film Lm that covers the entire surface of the wafer W, it is possible to prevent or suppress the re-adhesion of debris contained in the cleaning liquid (waste liquid) to surrounding devices after jet cleaning. This further improves the quality of the cleaning. Because the liquid jet has high liquid pressure, the liquid film does not interfere with jet cleaning. By creating a flow in the liquid film itself, it is possible to guide debris detached from the kerf by jet cleaning to the discharge path, further improving the cleaning effect.

[0058] In this embodiment, as in the second embodiment, the cleaning liquid supply unit 40 may be configured to include a fine bubble mixing unit 210 (see FIG. 9). The fine bubble mixing unit 210 may supply cleaning liquid mixed with fine bubbles to the cleaning head 20. The fine bubble mixing unit 210 may supply cleaning liquid mixed with fine bubbles to the cleaning unit 310. By mixing fine bubbles into the liquid film as well, the debris removal effect can be improved.

[0059] Although the preferred embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to this specific embodiment, and various modifications are possible within the scope of the technical concept of the present invention.

[0060] [Variations] FIG. 14 is a diagram schematically illustrating the configuration of a cleaning device according to a modified example. Although not mentioned in the above embodiment, the wafer W may be held so as to be tilted relative to the horizontal plane. In this modification, in the configuration of the third embodiment, the work table 12 is tilted so as to be lower in the X direction. In the illustrated example, the upper surface of the X table 356 of the workpiece holder 350 is tilted, but the upper surface of the Y table 18 may also be tilted.

[0061] As a result, the axis L of the turntable 14 is inclined with respect to the vertical axis (axis in the Z direction). This configuration can promote the flow of the liquid film in the X direction, and keep the surface of the wafer W clean. Note that an angle adjustment mechanism may be provided that can adjust the inclination angle of the work table 12, for example, by making the turntable 14 oscillating about a horizontal axis.

[0062] FIG. 15 is a diagram showing a usage mode of a cleaning device according to another modified example. In the above embodiment, an example was shown in which a liquid jet was ejected from above onto the wafer W. However, as shown in FIG. 15(A), the workpiece holder 10 may be installed so that the surface of the wafer W is oriented horizontally and the kerf K extends downward in the direction of gravity. The liquid jet LJ may then be ejected from the side. In this case, by moving the liquid jet LJ from a position above the kerf K to a position below it, gravity can be utilized to efficiently clean the kerf K.

[0063] In the illustrated example, the surface of the wafer W is along a vertical plane, i.e., forms an angle of 90 degrees with respect to the horizontal plane, but it may form a predetermined angle less than 90 degrees with respect to the horizontal plane. That is, the workpiece holder 10 may hold the wafer W so that the surface of the wafer W is inclined with respect to the horizontal plane, so that the cleaning liquid discharged toward the kerf K flows downward in the direction of gravity along the kerf K.

[0064] Alternatively, as shown in FIG. 15(B), the workpiece holder 10 may be installed so that the surface of the wafer W faces downward and the kerf K opens downward in the direction of gravity. Then, the liquid jet LJ may be discharged from below. The liquid jet LJ is moved along the kerf K. With this configuration, the cleaning liquid can be efficiently discharged from the kerf K by utilizing gravity. In the illustrated example, the surface of the wafer W is aligned along a horizontal plane, i.e., is arranged parallel to the horizontal plane, but it may also be at a predetermined angle of less than 90 degrees with respect to the horizontal plane.

[0065] [Other variations] In the above embodiment, an example was shown in which the work table 12 is configured to be movable in the X, Y, and θ directions, and the cleaning head 20 is configured to be movable in the Z direction. In a modified example, the work table 12 may be configured to be movable in the X and θ directions, and the cleaning head 20 may be configured to be movable in the Y and Z directions. Alternatively, the work table 12 may be configured to be movable only in the θ direction, and the cleaning head 20 may be configured to be movable in the X, Y, and Z directions. Other configurations may be adopted as long as the work table 12 and the cleaning head 20 can move relatively in the X, Y, Z, and θ directions.

[0066] In the above embodiment, the cleaning device 1 has been described as a device independent of the dicing device. In a modified example, the cleaning device may be realized by incorporating it into the dicing device. For example, the cleaning head may be provided so that it can move integrally with the processing head of the dicing device. A cleaning nozzle may be incorporated into the processing head. When using the blade dicing method, a cutting blade is provided in the processing head, and when using the laser dicing method, a laser output unit is provided in the processing head. By configuring it in this way, the workpiece holding unit can be shared between the dicing process and the cleaning process, making the entire device compact. Switching between each process can also be performed efficiently.

[0067] In the above embodiment, the diameter of the discharge port of the cleaning nozzle 34 is set smaller than the street width, specifically, to be approximately the same as the kerf width, so that the diameter of the liquid jet is approximately the same as the kerf width. In a modified example, the diameter of the discharge port may be set equal to or smaller than the kerf width. This makes it easier to achieve jet cleaning that is targeted at debris within the kerf. It also makes it easier to suppress the liquid jet from bouncing around the kerf, stabilizing cleaning. Alternatively, the diameter of the discharge port may be set larger than the kerf width but smaller than the street width.

[0068] In the above embodiment, the diameter of the discharge port of the cleaning nozzle 34 is set smaller than the street width. However, it may be substantially the same as or smaller than the street width. The term "substantially the same" may include a case where the diameter is slightly larger than the street width (specifically, within +10%, preferably within +5%). Depending on the liquid pressure of the liquid jet, the diameter of the liquid jet may be slightly smaller than the diameter of the discharge port. The influence of the shape of the discharge port, the spraying conditions of the cleaning liquid, the distance from the discharge port to the wafer, and other factors on the change in the diameter of the liquid jet also differ. Therefore, if the diameter of the liquid jet is set to be approximately the same as the street width while avoiding damage to the device, the diameter of the discharge port may be substantially the same as the street width. Furthermore, the diameter of the discharge port may be substantially the same as or smaller than the kerf width so that the diameter of the liquid jet is approximately the same as or smaller than the kerf width. The meaning of "substantially the same" is the same as above.

[0069] In the above embodiment, an example was shown in which a gas jet was simultaneously ejected to stabilize the liquid jet, but if the liquid jet is sufficiently stable, the supply of the gas jet may be omitted. Alternatively, the control unit may switch whether or not to eject the gas jet depending on the cleaning location on the wafer and the cleaning state. Also, the flow rate of the gas jet may be changed depending on the cleaning location and the cleaning state.

[0070] Although not mentioned in the above embodiment, jet cleaning and spin cleaning may be used in combination in the cleaning process of the wafer W. A cleaning liquid supply unit for performing spin cleaning may be provided, and spin cleaning may be performed at least either before or after jet cleaning.

[0071] In the above embodiment, an example has been shown in which the wafer W is fixed and held on the work table 12. In a modified example, the wafer W may be held in a manner in which it is held by a gripping device (not shown). For example, the peripheral edge of the wafer W may be held by an arm of the gripping device.

[0072] The present invention is not limited to the above-described embodiments and modifications, and the components can be modified without departing from the spirit of the invention. Various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments and modifications. Furthermore, some components can be omitted from all the components shown in the above-described embodiments and modifications. [Explanation of symbols]

[0073] 1 Cleaning device, 10 Workpiece holder, 12 Work table, 14 Rotating table, 16 X table, 18 Y table, 20 Cleaning head, 24 Y movement mechanism, 28 X movement mechanism, 30 Rotating mechanism, 32 Z table, 34 Cleaning nozzle, 34a Discharge outlet, 35 Air nozzle, 37 Angle adjustment mechanism, 38 Z movement mechanism, 40 Cleaning liquid supply unit, 41 Liquid supply path, 42 Gas supply unit, 43 Gas supply path, 44 Liquid supply source, 45 Branch path, 46 Pump, 47 Liquid supply path, 48 Flow control valve, 50 Control unit, 52 Gas supply source, 54 Opening / closing valve, 60 Chamber, 70 Dicing tape, 72 Frame, 201 Cleaning device, 210 Fine bubble mixing unit, 216 Flow control valve, 218 Injector, 240 Cleaning liquid supply unit, 301 Cleaning device, 310 Cleaning section, 312 flow control valve, 322 nozzle unit, 324 chamber, 326 liquid supply hole, 350 workpiece holding section, 356 X table, D device, Fv vertical surface, GJ gas jet, K kerf, LJ liquid jet, S1 street, S2 street, W wafer.

Claims

1. A kerf cleaning apparatus for cleaning kerfs formed along streets formed on a surface of a wafer by dicing the wafer into a plurality of devices, the apparatus comprising: a holder for holding the wafer; a cleaning nozzle that ejects a jet of cleaning liquid toward the kerf; a moving mechanism that moves the cleaning nozzle and the holding part relative to each other to move the liquid jet in the longitudinal direction of the kerf; Equipped with The kerf cleaning device, wherein the cleaning nozzle has a discharge opening with a diameter that is substantially the same as or smaller than the width of the street.

2. 2. The kerf washing device according to claim 1, wherein the discharge opening of the washing nozzle has a diameter that is substantially the same as or smaller than the width of the kerf.

3. The kerf washing device according to claim 1 or 2, further comprising an air nozzle that ejects a gas jet that surrounds the liquid jet, thereby suppressing the spread of the liquid jet.

4. The kerf cleaning apparatus according to claim 1 , further comprising an angle adjustment mechanism that adjusts an inclination angle of the cleaning nozzle relative to the surface of the wafer.

5. The kerf washing device according to claim 1, further comprising a fine bubble mixing unit for mixing microbubbles or nanobubbles into the washing liquid discharged as the liquid jet.

6. a first cleaning unit including the cleaning nozzle and configured to eject the liquid jet; a second cleaning unit that supplies a cleaning liquid to form a liquid film on the surface of the wafer separately from the liquid jet; The kerf cleaning device of claim 1 , comprising:

7. The kerf cleaning apparatus according to claim 6 , wherein the holding unit holds the wafer so that the surface of the wafer is inclined relative to a horizontal plane, thereby forming the flow of the liquid film.

8. 8. The kerf washing device according to claim 6, further comprising a fine bubble mixing unit for mixing microbubbles or nanobubbles into the washing liquid for forming the liquid film.

9. 2. The kerf cleaning device according to claim 1, wherein the holding unit holds the wafer so that the surface of the wafer is inclined with respect to a horizontal plane, so that the cleaning liquid discharged toward the kerf flows downward along the kerf in the direction of gravity.

10. the holder holds the wafer so that the front surface of the wafer faces downward; The kerf washing apparatus of claim 1 , wherein the washing nozzle discharges a liquid jet from below the kerf.

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