Incision cleaning device

Abstract

The invention provides a cleaning device suitable for cleaning a notch formed in a semiconductor wafer. According to one embodiment, a cleaning apparatus (1) cleans a notch formed along a trace by dicing a wafer (W) in which a plurality of devices are divided by the trace set on a surface. A cleaning apparatus (1) includes: a holding unit (10) that holds a wafer (W); a cleaning nozzle (34) that sprays a liquid jet for cleaning toward the cutout; and a moving mechanism that moves the liquid jet in the longitudinal direction of the cutout by moving the cleaning nozzle (34) and the holding part (10) relative to each other. The discharge port of the cleaning nozzle (34) has a diameter substantially equal to or less than the width of the trace.

Description

Technical Field

[0001] The present invention relates to an apparatus for cleaning a cut formed in a wafer due to cutting. Background Art

[0002] In the front process of semiconductor manufacturing, a wafer on which a plurality of devices are formed is divided into a plurality of chips for each device in a cutting process. On the surface of the wafer, a plurality of devices are formed, and each device is divided by a dividing line called a "street". In order to prevent the chips from becoming scattered, a bonding tape (hereinafter, also referred to as a "dicing tape") is pasted on the back surface of the wafer before cutting. In the cutting process, cutting is performed along the street from the surface side of the wafer, and the devices are divided.

[0003] As cutting methods, there are a blade cutting method in which a cutting blade is pressed against a wafer while performing cutting, a laser cutting method in which the surface of the wafer is separated by laser, and the like. Regardless of which method is used, a cut (groove) due to cutting is formed in the street on the surface of the wafer.

[0004] On the wall surface of the cut, fragments generated due to cutting may adhere. In addition, since the edge portion of the cut is brittle, a layer to be peeled off may sometimes be generated, and the peeled piece of the edge portion becomes a new fragment. When these fragments adhere to the device, there is a risk of occurrence of defects in subsequent processes (such as a wire bonding process). Regarding this point, a technique has been proposed in which, after processing the wafer, cleaning is performed to remove the fragments (see Patent Documents 1 and 2).

[0005] [Prior Art Documents]

[0006] [Patent Documents]

[0007] Patent Document 1: Japanese Patent Laid-Open No. 5-90237

[0008] Patent Document 2: Japanese Patent Laid-Open No. 2008-60284 Summary of the Invention

[0009] [Problems to be Solved by the Invention]

[0010] The cleaning device of Patent Document 1 removes debris remaining in the notch by so-called rotational cleaning. The cut wafer is held on a rotating table, and cleaning liquid is supplied from an oblique upper direction to the side surface of the notch, and the rotating table is rotated forward and backward. Thereby, the cleaning liquid can hit both side walls of the notch, and the debris can be rinsed off. The debris attached to the notch will fly off together with the cleaning liquid due to centrifugal force and be discharged to the outside. However, rotational cleaning generally supplies the cleaning liquid at a low pressure, so it may not be possible to sufficiently remove the debris due to the degree of attachment of the debris. In particular, since the rotation of the central part of the wafer is slow, it is difficult to obtain sufficient cleaning power. Regarding this point, increasing the rotation speed of the rotating table has also been considered, but when the rotation speed is increased too much, there is a possibility that the holding of the wafer will become unstable.

[0011] On the other hand, the cleaning device of Patent Document 2 cleans the surface of the substrate in the front process of semiconductor manufacturing. For the substrate after dry etching, foreign matter is removed by spraying the cleaning liquid obliquely along the wiring groove. Since the cleaning liquid is evenly sprayed on the entire surface of the substrate, the spraying pressure does not become so high, but it is considered that the foreign matter (resist residue, etc.) after dry etching can be sufficiently removed. On the other hand, during cutting, there may be cases where molten debris adheres, etc. Therefore, even if this cleaning device is applied to notch cleaning, in order to remove the debris in the notch, the hydraulic pressure is low and it is difficult to obtain sufficient cleaning effect. Regarding this point, increasing the spraying pressure of the cleaning liquid has also been considered, but there is a risk that the high-pressure cleaning liquid will also reach inside the chip and damage the device.

[0012] The present invention has been completed in view of such circumstances, and one of its purposes is to provide a cleaning device suitable for cleaning the notch formed in a semiconductor wafer.

[0013] [Technical solution for solving the technical problem]

[0014] One aspect of the present invention is a notch cleaning device that cleans a notch formed along a trace for a wafer in which a plurality of devices are divided by traces set on the surface by cutting. The cleaning device includes: a holding part that holds the wafer; a cleaning nozzle that sprays a liquid jet for cleaning toward the notch; and a moving mechanism that moves the liquid jet along the length direction of the notch by relatively moving the cleaning nozzle and the holding part. The ejection port of the cleaning nozzle has a diameter that is substantially the same as or less than the width of the trace.

[0015] Advantageous effects of the invention

[0016] According to the present invention, it is possible to provide a cleaning device suitable for cleaning the notch formed in a semiconductor wafer. Description of the drawings

[0017] Figure 1This is a diagram showing the schematic configuration of the cleaning device according to the first embodiment.

[0018] Figure 2 This is a diagram schematically showing the system configuration of the cleaning device.

[0019] Figure 3 This is a diagram schematically showing the configurations of the cleaning liquid supply section and the gas supply section.

[0020] Figure 4 This is a perspective view showing the structure of the wafer after dicing.

[0021] Figure 5 This is a top view of the wafer.

[0022] Figure 6 This is a diagram showing the change in the dicing process and the cross-sectional structure of the cut.

[0023] Figure 7 This is a diagram schematically showing the cleaning method for the cut.

[0024] Figure 8 This is a diagram schematically showing the cleaning method for the cut.

[0025] Figure 9 This is a diagram schematically showing the configuration of the cleaning device according to the second embodiment.

[0026] Figure 10 This is a diagram schematically showing the system configuration including the microbubble mixing section.

[0027] Figure 11 This is a diagram schematically showing the configuration of the cleaning device according to the third embodiment.

[0028] Figure 12 This is a diagram schematically showing the system configuration including the cleaning section.

[0029] Figure 13 This is a diagram schematically showing the configuration of the cleaning section.

[0030] Figure 14 This is a diagram schematically showing the configuration of the cleaning device of the modified example.

[0031] Figure 15 This is a diagram showing the usage scenario of the cleaning device of other modified examples. Detailed implementation manners

[0032] Hereinafter, with reference to the drawings, one embodiment of the present invention will be described. In addition, in the following embodiments and their modified examples, for substantially the same constituent elements, the same reference numerals are given, and their descriptions are appropriately omitted.

[0033] [First Embodiment]

[0034] The cleaning device of this embodiment cleans the surface of a semiconductor wafer (also simply referred to as "wafer") after cutting, and removes debris attached to the cut. As described above, since the width of the cut is as small as the micron level, the cleaning liquid is supplied in the form of a liquid jet so that the cleaning liquid spreads throughout the cut. By setting the diameter of the ejection port of the cleaning nozzle to be smaller than the width of the trace, the position where the liquid jet hits is restricted within the range of the trace, preventing damage to the devices on the surface of the wafer. That is, in this embodiment, efforts are made to both protect the devices on the wafer and ensure the cleaning intensity required for cleaning the cut. Hereinafter, the details will be described.

[0035] Figure 1 It is a diagram showing a schematic configuration of the cleaning device of the first embodiment.

[0036] In addition, hereinafter, for the sake of convenience in explanation, the cleaning device is observed from the front, and the front-rear direction, left-right direction, and up-down direction are respectively denoted as the X direction, Y direction, and Z direction for explanation.

[0037] The cleaning device 1 includes: a workpiece holding unit 10 that holds the wafer W; and a cleaning head 20 that ejects a liquid jet for cleaning onto the wafer W.

[0038] The wafer W has a cut formed on its surface through a cutting process. In addition, as cutting methods, in addition to the above-mentioned blade cutting and laser cutting, there is also plasma cutting, etc. The plasma cutting method is a method of dividing the wafer into chips by dry etching using plasma. In the laser cutting method, there are a laser ablation method in which the wafer is sublimated and evaporated by laser, and a laser internal processing method in which after a modified layer is formed inside the wafer by laser, separation is performed by tension (for example, the technology described in Japanese Patent No. 3408805). Regarding the cleaning device 1, regardless of which cutting method is performed, it can be applied to a wafer having a cut formed on its surface.

[0039] The workpiece holding unit 10 includes a workpiece table 12, a rotary table 14, an X table 16, and a Y table 18. The workpiece table 12 has a holding surface 12a that adsorbs and holds the wafer W. On the holding surface 12a, a plurality of adsorption holes are provided, and the plurality of adsorption holes are evacuated in order to adsorb the back surface of the wafer W. By driving a vacuum adsorption source (not shown), the wafer W can be adsorbed and fixed to the holding surface 12a.

[0040] On the base 2 of the cleaning device 1, a pair of guide rails 22 extending in the Y direction are provided. The Y worktable 18 is horizontally arranged so as to be movable in the Y direction along the guide rails 22. The Y worktable 18 is driven by a Y moving mechanism 24. On the upper surface of the Y worktable 18, a pair of guide rails 26 extending in the X direction are provided. The X worktable 16 is horizontally arranged so as to be movable in the X direction along the guide rails 26. The X worktable 16 is driven by an X moving mechanism 28. In the present embodiment, each moving mechanism is realized by a linear motor, but it may also be realized by a ball screw feed mechanism and a servo motor for driving the same.

[0041] The rotary table 14 is rotatably supported by the X worktable 16, and a workpiece table 12 is fixed on the upper surface of the rotary table 14. The rotary table 14 can be rotated by a rotation mechanism 30 about its own axis (in the θ direction around the axis L extending in the Z direction). The rotation mechanism 30 is realized by a spindle motor, for example. With such a configuration, the workpiece table 12 can be moved in the X direction, Y direction, and θ direction, respectively.

[0042] On the other hand, a Z worktable 32 is disposed on a column 4 erected on the base 2, and the cleaning head 20 is supported by the Z worktable 32. The cleaning head 20 includes a cleaning nozzle 34 that ejects a cleaning liquid as a liquid jet onto the wafer W.

[0043] On the front surface of the column 4, a pair of guide rails 36 extending in the Z direction are provided. The Z worktable 32 is arranged so as to be movable in the Z direction along the guide rails 36. The Z worktable 32 is driven by a Z moving mechanism 38. The Z moving mechanism 38 is realized by a ball screw feed mechanism and a servo motor for driving the same, for example. An angle adjustment mechanism 37 is provided on the Z worktable 32, and the angle adjustment mechanism 37 can adjust the tilt angle of the cleaning nozzle 34 with respect to the surface of the wafer W (details will be described later).

[0044] In the above configuration, the X moving mechanism 28, Y moving mechanism 24, Z moving mechanism 38, and rotation mechanism 30 function as "moving mechanisms" that relatively move the cleaning head 20 (i.e., the cleaning nozzle 34) and the workpiece table 12 (i.e., the wafer W).

[0045] Figure 2 It is a diagram schematically showing the system configuration of the cleaning device 1.

[0046] Regarding the cleaning device 1, in addition to the workpiece holding unit 10 and the cleaning head 20 described above, it further 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 the pressurized cleaning liquid (such as 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 the gas for stabilizing the liquid jet LJ to the cleaning head 20. The control unit 50 controls the cleaning liquid supply unit 40, the gas supply unit 42, and the above-mentioned moving mechanism.

[0047] Figure 3 It is a diagram schematically showing the configurations of the cleaning liquid supply unit 40 and the gas supply unit 42.

[0048] The cleaning liquid supply unit 40 includes a liquid supply source 44, a pump 46, and a flow control valve 48. In the liquid supply path 41 connecting the liquid supply source 44 and the cleaning head 20, the pump 46 and the flow control valve 48 are provided from the upstream side. The liquid supply source 44 has a tank for storing the cleaning liquid. By driving the pump 46, the cleaning liquid can be drawn from the liquid supply source 44 and supplied to the cleaning head 20. For the cleaning head 20, the pressurized cleaning liquid is supplied. 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 constituted by an electric valve driven by a motor, but it may also be a solenoid valve driven by a solenoid.

[0049] The gas supply unit 42 includes a gas supply source 52 and an opening / closing valve 54. In the gas supply path 43 connecting the gas supply source 52 and the cleaning head 20, the opening / closing valve 54 is provided. The gas supply source 52 has a tank for storing the pressurized gas. The opening / closing valve 54 is constituted by a solenoid valve, and the gas can be supplied from the gas supply path 43 to the cleaning head 20 by opening the opening / closing valve 54.

[0050] Return to Figure 2 , the cleaning head 20 includes a cleaning nozzle 34 and an air nozzle 35. The cleaning nozzle 34 ejects the cleaning liquid supplied from the cleaning liquid supply unit 40 as a liquid jet LJ. The air nozzle 35 is coaxially provided on the downstream side of the cleaning nozzle 34. A chamber 60 is formed between the cleaning nozzle 34 and the air nozzle 35. On the side wall of the cleaning head 20, an inlet port 62 communicating with the chamber 60 is provided, and the gas supply path 43 is connected to the inlet port 62.

[0051] The gas introduced from the inlet port 62 rotates around the liquid jet LJ and is introduced into the air nozzle 35, and is ejected as a gas jet GJ from the air nozzle 35. This gas flow (rotational flow) serves as a guiding wall to suppress the diffusion of the liquid jet LJ. That is, the liquid jet LJ is made to travel straight without diffusing. Therefore, the diameter of the liquid jet LJ hitting the wafer W is substantially equal to the diameter of the ejection port 34a of the cleaning nozzle 34.

[0052] The air nozzle 35 ejects 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 maintained in a state of being ejected linearly. The diameter of the liquid jet LJ ejected from the cleaning nozzle 34 toward the wafer W can be kept substantially constant. For example, it can be achieved by using the technique described in Japanese Patent No. 5437578.

[0053] The control unit 50 is composed of a general-purpose computer, includes a CPU that performs various arithmetic processes, a memory or storage device that stores control programs, etc., a memory used as a work area for data storage or program execution, an input / output interface, etc. The control unit 50 controls the driving of the cleaning liquid supply unit 40, the gas supply unit 42, and each moving mechanism according to the control program. In addition, in the present embodiment, it is assumed that the control unit 50 controls each part of the cleaning device, but it may also be provided with a control unit for each part.

[0054] Next, the notch cleaning method in the present embodiment will be described in detail.

[0055] Figure 4 It is a perspective view showing the structure of the wafer W after cutting.

[0056] The wafer W undergoes a cutting process, and thus lattice-shaped notches K (grooves) are formed so as to surround a plurality of devices D respectively. On the back surface of the wafer W, a dicing tape 70 is bonded, and the peripheral portion of the dicing tape 70 is fixed to an annular frame 72. The wafer W is fixed to the workpiece table 12 via the frame 72 (refer to Figure 1 ).

[0057] Figure 5 It is a top view of the wafer W. Figure 5 (A) of Figure 5 represents before cutting, Figure 5 (B) of Figure 5 represents after cutting. (C) of

[0058] is an enlarged view of part A of Figure 5As shown in (A) of , on the surface of the wafer W, as scribe lines for division, track S1 and track S2 that are orthogonal to each other are set. Track S1 extends in the X direction, and track S2 extends in the Y direction. A plurality of these tracks S1 and S2 are set on the surface of the wafer W and are configured in a lattice shape. Devices D are formed in the regions divided by these tracks S1 and S2.

[0059] As Figure 5 shown in (B) of , along these tracks S1 and S2, a cutting process is performed, and cuts K are formed in such a way as to pass through the center in the width direction of each of the tracks S1 and S2. In addition, in the present embodiment, since the widths of the tracks S1 and S2 are the same, they are collectively referred to as "track S" without particularly distinguishing between the two.

[0060] As Figure 5 shown in (C) of , the track S is the boundary dividing adjacent devices D, and the cut K is formed within the range of the track S. Regarding the width of the cut K (cut width Wk), in the present embodiment, it is several tens of μm, which is smaller than the width of the track S (track width Ws). Since the cut width Wk is extremely small, in order to make the cleaning liquid spread throughout the cut K, it is necessary to increase the cleaning intensity (hydraulic pressure).

[0061] On the other hand, when the high-pressure cleaning liquid hits the device D, it may affect the device D. Therefore, in the present embodiment, the diameter of the liquid jet ejected into the cut K is set to be about the same as the cut width Wk and at least smaller than the track width Ws. Alternatively, the diameter of the liquid jet may be made smaller than the cut width Wk (details will be described later).

[0062] Figure 6 is a diagram showing a change in the cutting process and the cross-sectional structure of the cut.

[0063] In the cutting process, there are types such as full-cut processing, half-cut processing, and grooving processing. As Figure 6 shown in (A) of , regarding full-cut processing, the cutting depth reaches the entire height of the wafer W. Therefore, the cut K reaches the cutting tape 70, but the cutting tape 70 is not cut off, and the chips do not become scattered.

[0064] As Figure 6 shown in (B) of , regarding half-cut processing, the cutting depth does not reach the entire height of the wafer W. Therefore, afterwards, processes such as thinning and chip separation while grinding, or laser internal processing and expansion, or a full-cut process based on blade cutting are required. As Figure 6As shown in (C), regarding grooving processing, in the wafer W, only the wiring layer is cut under conditions optimized for cutting the wiring layer, and then processes such as laser internal processing and expansion, or a full-cut process based on blade cutting are required. Regardless of which cutting process is used, a cut K is formed. These cuts K become the objects to be cleaned.

[0065] Figure 7 and Figure 8 are diagrams schematically showing a cleaning method for the cuts. Figure 7 (A) of shows a control method for the moving mechanism in the cleaning device 1. Figure 7 (B) of is Figure 7 an enlarged view of part B of (A) of. The blank arrows in the figure indicate the relative movement direction of the cleaning nozzle 34 with respect to the wafer W.

[0066] As Figure 7 shown in (A) of, in the cut 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, and performs jet cleaning along the cut K. By driving the X moving mechanism 28, the cleaning nozzle 34 can be relatively moved with respect to the wafer W in the X direction, so that the liquid jet LJ moves along the length direction of the cut K. At this time, the cleaning nozzle 34 (cleaning head 20) is relatively moved with respect to the wafer W along the vertical plane Fv including the cut K, and the liquid jet LJ is ejected.

[0067] As Figure 7 shown in (B) of, the width Wk and depth h of the cut K are set to several tens of μm, but on the inner wall surface of the cut K immediately after cutting, fine fragments d are attached. In addition, at the edge portion of the cut K, a peeled piece f is sometimes generated. The liquid jet LJ has a hydraulic pressure capable of flushing them away only. In the present embodiment, the diameter of the jet outlet 34a of the cleaning nozzle 34 is set to several tens of μm on the same order as the cut width Wk. In addition, the hydraulic pressure (ejection pressure) of the liquid jet LJ is set to be sufficiently high, for example, in the range of 100 to 600 bar. Therefore, the hydraulic pressure acting on the position where the liquid jet LJ hits is also of the same order, and the liquid jet LJ can be sufficiently spread within the cut K.

[0068] Figure 8 (A) of is along Figure 7 (A) of the vertical plane Fv, Figure 8 (B) of is Figure 8 a view in the C direction of (A) of.

[0069] As Figure 8As shown in (A), for the surface of the wafer W, the cleaning nozzle 34 (specifically, the axis L1 of the jet outlet 34a) is set at a predetermined inclination angle θ1 (for example, 45 degrees). The cleaning device 1 is provided with the above-described angle adjustment mechanism 37 (refer to Figure 1 ), and can appropriately adjust the inclination angle θ1 of the cleaning nozzle 34 with respect to the surface of the wafer W (that is, the ejection angle of the liquid jet LJ with respect to the surface of the wafer W).

[0070] In this embodiment, the angle adjustment mechanism 37 includes a goniometer stage (not shown) and the like, and can manually adjust the angle of the cleaning head 20 with respect to the workpiece stage 12. Alternatively, in a modified example, the angle adjustment mechanism 37 includes a stepping motor that rotates the cleaning head 20 around a horizontal axis. Alternatively, the control unit 50 can automatically adjust the angle by controlling the motor.

[0071] The cleaning nozzle 34 ejects the liquid jet LJ obliquely downward in the forward traveling direction relative to the wafer W. Therefore, the cleaning liquid ejected first can be discharged from the notch K together with the debris by being pushed forward. As Figure 8 shown in (B), the liquid jet LJ converges within the notch K, and cleaning is performed with high efficiency. After cleaning the notch K along the track S1, the workpiece stage 12 is rotated 90 degrees by the rotation mechanism 30, so that the notch K along the track S2 can be cleaned (refer to Figure 5 (B)).

[0072] In addition, for the inclination angle θ1, it is also possible to preset a good cleaning correspondence relationship based on experiments or the like for cleaning conditions such as the ejection pressure or ejection flow rate of the liquid jet LJ, and the inclination angle of the cleaning nozzle 34 with respect to the wafer W. Among the cleaning conditions, in addition to this, it also includes the type of cutting, the presence or absence of a liquid film (third embodiment) described later, and the like.

[0073] As described above, in this embodiment, by setting the diameter of the jet outlet 34a of the cleaning nozzle 34 to be equal to or less than the notch width Wk, the diameter of the liquid jet LJ can be made approximately the same as the notch width Wk. Thus, jet cleaning for the notch K can be easily achieved. In order to avoid the liquid jet LJ directly hitting the device D, the hydraulic pressure can be set relatively high. Therefore, the cleaning intensity required for notch cleaning can be sufficiently ensured, and the cleaning efficiency can be improved.

[0074] In particular, in the case of using laser ablation, burrs are generated at the edges of the formed incisions. Therefore, by setting the diameter of the liquid jet LJ to be equal to or greater than the incision width Wk and equal to or less than the track width Ws, a higher cleaning effect can be obtained. However, by scanning the ejection position of the liquid jet LJ while offsetting it in the Y direction from the center of the incision, even if the diameter of the liquid jet LJ is smaller than the incision width Wk, the burrs can be removed.

[0075] [Second Embodiment]

[0076] The cleaning device of the present embodiment is different from the first embodiment in that fine bubbles are mixed into the liquid jet ejected from the cleaning nozzle.

[0077] Figure 9 FIG. schematically shows the configuration of the cleaning device of the second embodiment.

[0078] The cleaning liquid supply unit 240 of the cleaning device 201 includes a fine bubble mixing unit 210. The fine bubble mixing unit 210 mixes microbubbles or nanobubbles into the cleaning liquid on the upstream side of the cleaning nozzle 34. Hereinafter, microbubbles or nanobubbles will be collectively referred to as "fine bubbles" as appropriate.

[0079] Figure 10 FIG. schematically shows the system configuration including the fine bubble mixing unit 210.

[0080] In the present embodiment, a branch path 45 branched from the middle of the gas supply path 43 is provided. 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.

[0081] The fine bubble mixing unit 210 generates fine bubbles by an injection method, and includes a pressure increasing valve 212, a pressure increasing tank 214, a flow control valve 216, and an injector 218 from the upstream side of the branch path 45. A part of the gas supplied from the gas supply source 52 is pressurized by the pressure increasing valve 212 and stored in the pressure increasing tank 214. By adjusting the opening degree of the flow control valve 216, the supply amount of the pressurized gas is controlled. In the present embodiment, the flow control valve 216 is constituted by an electric valve, but it may also be a solenoid valve.

[0082] The pressurized gas is ejected from the nozzle of the ejector 218 into the liquid supply path 41 and is 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 micron-sized bubbles or nano-sized bubbles is generated. Each part of the fine bubble mixing section 210 is controlled by the control section 50. By controlling the flow control valve 48 and the flow control valve 216 respectively by the control section 50, it is possible to adjust whether to mix fine bubbles into the cleaning liquid and the mixing amount.

[0083] In addition, as a method of generating fine bubbles in the cleaning liquid, in addition to the injection method, there are also the cavitation method of generating fine bubbles by sucking gas into the swirling flow of the pressurized cleaning liquid to crush the gas, the gas-liquid agitation method of generating fine bubbles by supplying gas to the pressurized cleaning liquid while stirring at high speed to refine the bubbles existing in the cleaning liquid, and the gas dispersion method of generating fine bubbles by passing gas through a porous body immersed in the cleaning liquid, etc. (for example, refer to Japanese Patent Laid-Open No. 2008-253893). Any one of these methods can be adopted, but as the fine bubbles, those mixed in have a diameter that is sufficiently small compared to the diameter of the liquid jet LJ, that is, sufficiently small compared to the diameter of the ejection hole 34a (several tens of μm or less).

[0084] Return to Figure 9 , the control section 50 can cause the fine bubble mixing section 210 to operate so that the state in which fine bubbles are mixed into the cleaning liquid is ejected as a liquid jet LJ from the cleaning nozzle 34. According to the present embodiment, it is possible to adsorb debris on the fine bubbles in the cleaning liquid and wash it away, and it is possible to further improve the cleaning efficiency of the cut K.

[0085] [Third Embodiment]

[0086] The cleaning device of the present embodiment is different 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.

[0087] Figure 11 is a diagram schematically showing the configuration of the cleaning device of the third embodiment.

[0088] The cleaning device 301 is different from the jet cleaning based on the cleaning head 20 and includes a cleaning section 310 that supplies the cleaning liquid in such a way as to form a liquid film Lm on the surface of the wafer W. The cleaning head 20 functions as the "first cleaning section", and the cleaning section 310 functions as the "second cleaning section".

[0089] In the present embodiment, the cleaning unit 310 is provided integrally with the workpiece table 12. However, in a modified example, it may be provided as a cleaning device independent of the workpiece holding unit 10. A liquid supply path 47 that connects the cleaning liquid supply unit 40 and the cleaning unit 310 is provided, and the cleaning liquid is supplied from the cleaning liquid supply unit 40 to the cleaning unit 310. From the cleaning unit 310, the low-pressure cleaning liquid is supplied in a drenching manner rather than a liquid jet.

[0090] Figure 12 FIG. is a schematic diagram showing the system configuration including the cleaning unit 310.

[0091] The liquid supply path 47 is provided so as to branch from the downstream side of the pump 46 in the liquid supply path 41 and is connected to the cleaning unit 310. A flow control valve 312 is provided in the liquid supply path 47. By driving the pump 46, the cleaning liquid is also supplied to the liquid supply path 47. The flow control valve 312 controls the flow rate of the cleaning liquid supplied to the cleaning unit 310. In the present embodiment, the flow control valve 312 is constituted by an electric valve, but a solenoid valve may also be used.

[0092] Figure 13 FIG. is a schematic diagram showing the configuration of the cleaning unit 310.

[0093] The cleaning unit 310 includes: a block 320 fixed to the workpiece table 12; and a nozzle unit 322 mounted on the block 320. The nozzle unit 322 includes: a chamber 324 communicating with the liquid supply path 47; and a plurality of liquid supply holes 326 communicating with the chamber 324. The nozzle unit 322 has an arc-shaped side surface on the wafer W side, and a plurality of liquid supply holes 326 are arranged on the side surface. Any one of the liquid supply holes 326 opens toward the wafer W side.

[0094] The cleaning liquid supplied through the liquid supply path 47 is stored in the chamber 324 and ejected from each liquid supply hole 326 onto the surface of the wafer W. The cleaning liquid forms a liquid film on the surface of the wafer W and flows in a direction away from the cleaning nozzle 34 on the surface of the wafer W, and is introduced into a drainage path (not shown). That is, on the surface of the wafer W, the flow direction of the cleaning liquid ejected from the cleaning nozzle 34 and the flow direction of the cleaning liquid ejected from the nozzle unit 322 are set to the same direction.

[0095] According to the present embodiment, it is possible to prevent or suppress the reattachment of debris contained in the cleaning liquid (waste liquid) to peripheral devices after jet cleaning by forming a thin liquid film Lm covering the entire surface of the wafer W. Thereby, the quality after cleaning can be further improved. Since the hydraulic pressure of the liquid jet is high, the liquid film does not hinder the jet cleaning. By creating a flow in the liquid film itself, it is also possible to lead the debris detached from the notch due to the jet cleaning to the discharge path, and the cleaning effect can be further improved.

[0096] In addition, in the present embodiment, similarly to the second embodiment, the cleaning liquid supply unit 40 may also be configured to include a microbubble mixing unit 210 (see Figure 9 ). Alternatively, the microbubble mixing unit 210 may supply the cleaning liquid mixed with microbubbles to the cleaning head 20. Alternatively, the microbubble mixing unit 210 may supply the cleaning liquid mixed with microbubbles to the cleaning unit 310. By mixing microbubbles into the liquid film as well, the removal effect of debris can be improved.

[0097] As described above, although the preferred embodiments of the present invention have been described, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the technical idea of the present invention, of course.

[0098] [Modification Example]

[0099] Figure 14 FIG. schematically shows the configuration of a cleaning device according to a modification example.

[0100] Although not described in the above embodiments, it is also possible to hold the wafer W so as to be inclined with respect to the horizontal plane. In this modification example, in the configuration of the third embodiment, the workpiece stage 12 is inclined so as to be lower in the X direction. In the illustrated example, the upper surface of the X stage 356 of the workpiece holding unit 350 is inclined, but alternatively, the upper surface of the Y stage 18 may be inclined.

[0101] As a result, the axis L of the rotary table 14 is inclined with respect to the vertical axis (axis in the Z direction). With this configuration, the flow of the liquid film in the X direction can be promoted, and the surface of the wafer W can be kept clean. In addition, for example, it is also possible to make the rotary table 14 swingable with respect to the horizontal axis, etc., and an angle adjustment mechanism for adjusting the inclination angle of the workpiece stage 12 is provided.

[0102] Figure 15 FIG. shows a usage scenario of a cleaning device according to another modification example.

[0103] In the above embodiments, an example of ejecting a liquid jet from above the wafer W has been shown, but as shown in Figure 15 (A) of, it is also possible to orient the surface of the wafer W horizontally and arrange the workpiece holding unit 10 such that the notch K extends downward in the direction of gravity. Then, it is also possible to eject the liquid jet LJ from the side. At this time, by moving the liquid jet LJ from a position above the notch K to a position below, cleaning can be efficiently performed using gravity.

[0104] In the illustrated example, the surface of the wafer W is along a vertical plane, that is, at 90 degrees with respect to the horizontal plane, but it can also be set to a predetermined angle less than 90 degrees with respect to the horizontal plane. That is, it can also be that the workpiece holding part 10 holds the wafer W in such a way that the surface of the wafer W is inclined with respect to the horizontal plane, whereby the cleaning liquid ejected toward the notch K flows downward along the notch K in the direction of gravity.

[0105] Alternatively, it can also be, as Figure 15 shown in (B) of FIG., the surface of the wafer W is set downward, and the workpiece holding part 10 is arranged such that the notch K opens downward in the direction of gravity. And it can also be that the liquid jet LJ is ejected from below. The liquid jet LJ is moved along the notch K. With such a configuration, the cleaning liquid can be efficiently discharged from the notch K by gravity. In the illustrated example, the surface of the wafer W is along the horizontal plane, that is, arranged parallel to the horizontal plane, but it can also be set to a predetermined angle less than 90 degrees with respect to the horizontal plane.

[0106] [Other modification examples]

[0107] In the above-described embodiment, an example in which the workpiece table 12 is configured to be movable in the X direction, Y direction, and θ direction, and the cleaning head 20 is configured to be movable in the Z direction is shown. In a modification example, it can also be that the workpiece table 12 is configured to be movable in the X direction and θ direction, and the cleaning head 20 is configured to be movable in the Y direction and Z direction. Alternatively, it can also be that the workpiece table 12 is configured to be movable only in the θ direction, and the cleaning head 20 is configured to be movable only in the X direction, Y direction, and Z direction. As long as the workpiece table 12 and the cleaning head 20 can move relative to each other in the X direction, Y direction, Z direction, and θ direction, other configurations can also be adopted.

[0108] In the above-described embodiment, the cleaning device 1 has been described as a device independent of the cutting device. However, in a modification example, it can also be that the cleaning device is implemented in the form of being assembled to the cutting device. For example, it can also be that the cleaning head is set to be movable integrally with the processing head of the cutting device. It can also be that the cleaning nozzle is assembled to the processing head. In the case of the blade cutting method, a cutting blade is provided in the processing head, and in the case of the laser cutting method, a laser output unit is provided in the processing head. With such a configuration, the workpiece holding part can be shared in the cutting process and the cleaning process, and the entire device can be configured compactly. The switching between the respective processes can also be performed efficiently.

[0109] In the above-described embodiment, the diameter of the liquid jet is made to be about the same as the width of the cut, and the diameter of the discharge port of the cleaning nozzle 3 is set to be smaller than the width of the track. Specifically, it is set to be about the same as the width of the cut. In a modified example, the diameter of the discharge port may be set to be equal to or less than the width of the cut. Thereby, jet cleaning of the debris in the cut becomes easier. In addition, the rebound of the liquid jet at the periphery of the cut is suppressed, and the cleaning is stabilized. Alternatively, the diameter of the discharge port may be larger than the width of the cut and smaller than the width of the track.

[0110] In the above-described embodiment, an example is shown in which the diameter of the discharge port of the cleaning nozzle 34 is set to be smaller than the width of the track, but it may be substantially the same as the width of the track or set to be equal to or less than the width of the track. In "substantially the same", a case where it is slightly larger than the width of the track may be included (specifically, within +10%, preferably within +5%). Depending on the hydraulic pressure of the liquid jet, the diameter of the liquid jet may sometimes be slightly smaller than the diameter of the discharge port. Depending on the shape of the discharge port, the injection conditions of the cleaning liquid, the distance from the discharge port to the wafer, etc., the influence on the change in the diameter of the liquid jet is also different. Therefore, in the case of avoiding damage to the device and making the diameter of the liquid jet about the same as the width of the track, the diameter of the discharge port may be substantially the same as the width of the track. In addition, the diameter of the discharge port may be substantially the same as the width of the cut or made to be equal to or less than the width of the cut so that the diameter of the liquid jet is about the same as or less than the width of the cut. The meaning of "substantially the same" is the same as above.

[0111] In the above-described embodiment, an example is shown in which a gas jet is ejected simultaneously to stabilize the liquid jet, but in the case where the liquid jet is sufficiently stable, the supply of the gas jet may be omitted. Alternatively, the control unit may switch the ejection of the gas jet according to the cleaning position and the cleaning state in the wafer. In addition, the flow rate of the gas jet may be changed according to the cleaning position and the cleaning state.

[0112] Although not described in the above-described embodiment, in the cleaning process of the wafer W, jet cleaning and rotational cleaning may be used in combination. Alternatively, a cleaning liquid supply unit for performing rotational cleaning may be provided, and rotational cleaning may be performed at least any one of before, during, and after the jet cleaning.

[0113] In the above-described embodiment, an example is shown in which the wafer W is fixed and held on the workpiece table 12. In a modified example, the wafer W may be held by a holding device (not shown). For example, the peripheral portion of the wafer W may be held by the arm of the holding device.

[0114] In addition, the present invention is not limited to the above-described embodiments or modified examples, and constituent elements can be deformed and embodied without departing from the gist. It is also possible to form various inventions by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments or modified examples. Further, it is also possible to delete some constituent elements from all the constituent elements shown in the above-described embodiments or modified examples.

[0115] [Description of Reference Numerals]

[0116] 1 Cleaning device, 10 Workpiece holding part, 12 Workpiece table, 14 Rotary table, 16 X table, 18 Y table, 20 Cleaning head, 24 Y moving mechanism, 28 X moving mechanism, 30 Rotating mechanism, 32 Z table, 34 Cleaning nozzle, 34a Jet outlet, 35 Air nozzle, 37 Angle adjustment mechanism, 38 Z moving mechanism, 40 Cleaning liquid supply part, 41 Liquid supply path, 42 Gas supply part, 43 Gas supply path, 44 Liquid supply source, 45 Branch path, 46 Pump, 47 Liquid supply path, 48 Flow control valve, 50 Control part, 52 Gas supply source, 54 On-off valve, 60 Chamber, 70 Cutting tape, 72 Frame, 201 Cleaning device, 210 Microbubble mixing part, 216 Flow control valve, 218 Injector, 240 Cleaning liquid supply part, 301 Cleaning device, 310 Cleaning part, 312 Flow control valve, 322 Nozzle unit, 324 Chamber, 326 Liquid supply hole, 350 Workpiece holding part, 356 X table, D Device, Fv Vertical plane, GJ Gas jet, K Notch, LJ Liquid jet, S1 Trace, S2 Trace, W Wafer.

Claims

1. A cut cleaning device that cleans a cut formed along a track, the cut being formed by cutting a wafer in which a plurality of devices are defined by tracks provided on a surface. The cut cleaning device includes: a holding unit that holds the wafer, a cleaning nozzle that ejects a liquid jet for cleaning toward the cut, and a moving mechanism that moves the cleaning nozzle relative to the holding unit so that the liquid jet moves along the length direction of the cut; The ejection port of the cleaning nozzle has a diameter that is substantially the same as or smaller than the width of the track.

2. The cut cleaning device according to claim 1, wherein the ejection port of the cleaning nozzle has a diameter that is substantially the same as or smaller than the width of the cut.

3. The cut cleaning device according to claim 1 or 2, wherein it further includes an air nozzle that suppresses the diffusion of the liquid jet by ejecting a gas jet that surrounds the liquid jet.

4. The cut cleaning device according to claim 1, wherein it further includes an angle adjustment mechanism that can adjust the tilt angle of the cleaning nozzle relative to the surface of the wafer.

5. The cut cleaning device according to claim 1, wherein it further includes a microbubble mixing unit that mixes microbubbles or nanobubbles into the cleaning liquid ejected as the liquid jet.

6. The cut cleaning device according to claim 1, including: a first cleaning unit that includes the cleaning nozzle and ejects the liquid jet, and a second cleaning unit that supplies the cleaning liquid in a manner different from the liquid jet to form a liquid film on the surface of the wafer.

7. The cut cleaning device according to claim 6, wherein the holding unit holds the wafer so that the surface of the wafer is inclined with respect to the horizontal plane, thereby forming the flow of the liquid film.

8. The cut cleaning device according to claim 6 or 7, wherein it further includes a microbubble mixing unit that mixes microbubbles or nanobubbles into the cleaning liquid for forming the liquid film.

9. The cut 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 the horizontal plane, whereby the cleaning liquid ejected toward the cut flows downward along the cut in the direction of gravity.

10. The cut cleaning device according to claim 1, wherein the holding unit holds the wafer so that the surface of the wafer faces downward; the cleaning nozzle ejects a liquid jet from below the cut.

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