JP2012250260A - Powder dust discharging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder dust discharging device in which fire caused by powder dust such as debris caused by irradiation of a laser beam can be prevented.SOLUTION: The powder dust discharging device is used for discharging the powder dust produced by irradiating a workpiece with a laser beam from the condenser of a laser beam irradiation means and includes: a powder dust suction member which opens toward the irradiation part of the laser beam emitted from the condenser; a duct the one end of which is connected to the powder dust suction member; and an exhaust means which is connected to the other end of the duct. A first transmission window and a second transmission window made of transparent members which permeate light are mutually oppositely arranged at the side walls of the duct. The device further includes: a light emitting means which emits light toward the second transmission window through the first transmission window; a light receiving means which receives the light emitted by the light emitting means through the second transmission window; and a controlling means which decides the degree of the deposition of the powder dust stuck to the inside face of the duct based on the light quantity of the light received by the light receiving means.

Description

  The present invention relates to a dust discharge device for processing dust such as debris generated during laser processing.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a semiconductor substrate having a substantially disk shape, and devices such as ICs, LSIs, etc. are partitioned in these partitioned regions. Form. Then, the semiconductor wafer is cut along the streets to divide the region in which the device is formed to manufacture individual devices. In addition, optical device wafers in which light-receiving elements such as photodiodes and light-emitting elements such as laser diodes are stacked on the surface of the sapphire substrate are also divided into optical devices such as individual photodiodes and laser diodes by cutting along the streets. And widely used in electrical equipment.

  As a method of dividing the wafer such as the semiconductor wafer or the optical device wafer described above along the street, a laser processing groove is formed by irradiating a pulse laser beam along the street formed on the wafer, and along the laser processing groove. The method of breaking is practically used. However, when laser light is irradiated along the street of the wafer, thermal energy concentrates on the irradiated area and debris is generated. This debris adheres to the bonding pads connected to the circuit and degrades the quality of the chip. New problems arise. In order to solve such a problem, a laser processing method has been proposed in which a processed film of a wafer is coated with a protective film such as polyvinyl alcohol, and the wafer is irradiated with a laser beam through the protective film. (For example, refer to Patent Document 1.)

JP 2004-188475 A

  As described above, when a wafer, which is a workpiece, is irradiated with a laser beam, debris is generated, and dust containing the debris is scattered. Therefore, the laser processing apparatus includes a dust discharging means for sucking and discharging the scattered dust. Yes. However, if dust accumulates in the suction duct of the dust discharge means and high-temperature debris scattered on the accumulated dust adheres, there is a problem that a fire occurs due to ignition. In particular, when a laser processing method in which a wafer is processed with a protective coating such as polyvinyl alcohol and the wafer is irradiated with a laser beam through the protective coating, the accumulated dust is ignited and a fire occurs. The rate of occurrence is high.

  This invention is made | formed in view of the said fact, The main technical subject is to provide the dust discharge apparatus which can prevent the fire by dust, such as a debris generated by irradiating a laser beam. .

In order to solve the above main technical problem, according to the present invention, in a dust discharge device for discharging dust generated by irradiating a workpiece with a laser beam from a condenser of a laser beam irradiation means,
A dust suction member that opens toward the irradiation part of the laser beam emitted from the light collector; a duct having one end connected to the dust suction member; and an exhaust means connected to the other end of the duct. And
A first transmission window and a second transmission window made of a transparent member that transmits light are disposed on the side wall of the duct so as to face each other.
A light emitting means for emitting light toward the second transmission window through the first transmission window; a light receiving means for receiving light emitted by the light emission means through the second transmission window; and Control means for determining the degree of accumulation of dust adhering to the inner surface of the duct based on the light quantity of the light,
A dust discharge device is provided.

A dust discharge device according to the present invention includes a dust suction member that opens toward an irradiation portion of a laser beam emitted from a condenser, a duct having one end connected to the dust suction member, and an exhaust connected to the other end of the duct. Therefore, dust such as debris generated by the irradiation of the laser beam is sucked from the dust suction member to the exhaust means through the duct.
In the dust discharge device according to the present invention, the first transmission window and the second transmission window made of a transparent member that transmits light are disposed opposite to each other on the side wall of the duct. A light emitting means for emitting light toward the second transmission window, a light receiving means for receiving the light emitted by the light emitting means through the second transmission window, and an inner surface of the duct based on the amount of light received by the light receiving means Control means for determining the degree of accumulation of dust attached to the first and second transmission windows, so that the degree of accumulation of dust attached to the first transmission window and the second transmission window can be determined. The viewing operator removes the dust accumulated in the duct and cleans it. Therefore, it is possible to prevent a fire that is generated by igniting dust that is scattered by a laser beam, high-temperature debris, or the like accumulated in a duct in a predetermined amount or more.

The perspective view of the laser processing machine equipped with the dust discharge apparatus comprised according to this invention. The perspective view of the semiconductor wafer as a wafer which is a workpiece. The perspective view which fractures | ruptures and shows a part of protective film coating and washing | cleaning means with which the laser beam machine shown in FIG. 1 is equipped. Explanatory drawing which shows the state which positioned the spinner table of the protective film coating and washing | cleaning means shown in FIG. 3 in the workpiece carrying in / out position. Explanatory drawing which shows the state which located the spinner table of the protective film coating and washing | cleaning means shown in FIG. 3 in the working position. The perspective view which fractures | ruptures and shows a part of dust discharge device with which the laser processing apparatus shown in FIG. 1 is equipped. Sectional drawing of the duct which comprises the dust discharge apparatus shown in FIG. Explanatory drawing of the protective film coating process implemented by the protective film coating and washing | cleaning means shown in FIG. Explanatory drawing which shows the laser processing groove | channel formation process implemented using the laser processing apparatus shown in FIG. The principal part expanded sectional view of the semiconductor wafer in which the laser processing groove | channel was formed by the laser processing groove | channel formation process shown in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a laser beam machine equipped with a dust discharge device constructed according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a laser beam machine 1 equipped with a dust discharge device constructed according to the present invention.
A laser beam machine 1 shown in FIG. 1 includes a device housing 2 having a substantially rectangular parallelepiped shape. A chuck table 3 for holding a wafer as a workpiece is disposed in the apparatus housing 2 so as to be movable in a machining feed direction indicated by an arrow X and an index feed direction Y orthogonal to the machining feed direction X. . The chuck table 3 includes a suction chuck support 31 and a suction chuck 32 mounted on the suction chuck support 31, and is a workpiece on a mounting surface that is a surface of the suction chuck 32. The wafer is held by suction means (not shown). The chuck table 3 is configured to be rotatable by a rotation mechanism (not shown). The suction chuck support 31 of the chuck table 3 configured as described above is provided with a clamp 34 for fixing an annular frame described later. The laser machining apparatus 1 includes a machining feed means (not shown) for feeding the chuck table 3 in the machining feed direction X and an index feed means (not shown) for indexing and feeding in the index feed direction Y.

  The illustrated laser beam machine 1 includes a laser beam irradiation means 4 that performs laser beam processing on a wafer as a workpiece held on the chuck table 3. The laser beam irradiation unit 4 includes a laser beam oscillation unit 41 and a condenser 42 that condenses the laser beam oscillated by the laser beam oscillation unit 41. The laser beam machining apparatus 1 moves the laser beam oscillation unit 41 in a focusing point position adjusting unit (not shown) that moves in a focusing point position adjusting direction indicated by an arrow Z that is perpendicular to the mounting surface that is the upper surface of the chuck table 3. It has.

  The illustrated laser beam machine 1 captures an image of the surface of the workpiece held on the suction chuck 32 of the chuck table 3 and is to be processed by a laser beam irradiated from the condenser 42 of the laser beam irradiation means 4. The imaging means 5 which detects this is provided. The imaging unit 5 includes an infrared illumination unit that irradiates a workpiece with infrared rays, an optical system that captures infrared rays emitted by the infrared illumination unit, in addition to a normal imaging device (CCD) that captures visible light. An image sensor (infrared CCD) that outputs an electrical signal corresponding to the infrared rays captured by the optical system is used, and the captured image signal is sent to a control means to be described later. The illustrated laser processing apparatus includes a display unit 6 that displays an image captured by the imaging unit 5.

  The illustrated laser beam machine 1 includes a cassette mounting portion 11a on which a cassette for housing a semiconductor wafer 10 as a wafer to be processed is mounted. A cassette table 111 is disposed on the cassette mounting portion 11 a so as to be movable up and down by lifting means (not shown). The cassette 11 is mounted on the cassette table 111. The semiconductor wafer 10 is attached to the surface of the protective tape T attached to the annular frame F, and is accommodated in the cassette 11 while being supported by the annular frame F via the protective tape T. The semiconductor wafer 10 is made of a silicon wafer, and a plurality of regions are partitioned by a plurality of division lines 101 arranged in a lattice pattern on the surface 10a as shown in FIG. 2, and ICs, LSIs, etc. are partitioned in these partitioned regions. Device 102 is formed. As shown in FIG. 1, the semiconductor wafer 10 configured in this manner is attached to the protective tape T mounted on the annular frame F with the front surface 10a, that is, the surface on which the street 101 and the device 102 are formed facing upward. Worn.

  The illustrated laser beam machine 1 carries out the unprocessed semiconductor wafer 10 housed in the cassette 11 to the alignment means 12 disposed in the temporary placement portion 12 a and also loads the processed semiconductor wafer 10 into the cassette 11. The wafer unloading / loading means 13 and the unprocessed semiconductor wafer 10 unloaded to the alignment means 12 are transported to a protective film coating / cleaning means 7 to be described later, and a protective film is coated on the surface by the protective film coating / cleaning means 7. A first wafer transport means 14 for transporting the coated semiconductor wafer 10 onto the chuck table 3 and a second wafer for transporting the semiconductor wafer 10 processed on the chuck table 3 to the protective film coating / cleaning means 7. Conveying means 15 is provided.

Next, a protective film is applied to the surface (processed surface) of the semiconductor wafer 10 that is a workpiece before processing, and the protective film coated on the surface of the semiconductor wafer 10 after processing is removed. The cleaning means 7 will be described with reference to FIGS.
The protective film coating / cleaning means 7 in the illustrated embodiment includes a spinner table mechanism 71 and a water receiving means 72 disposed so as to surround the spinner table mechanism 71. The spinner table mechanism 71 includes a spinner table 711, an electric motor 712 as a rotational drive unit that rotationally drives the spinner table 711, and a support unit 713 that supports the electric motor 712 so as to be movable in the vertical direction. . The spinner table 711 includes a suction chuck 711a formed of a porous material, and the suction chuck 711a communicates with suction means (not shown). Accordingly, the spinner table 711 holds the wafer on the suction chuck 711 by placing a wafer as a workpiece on the suction chuck 711a and applying a negative pressure by suction means (not shown). The electric motor 712 connects the spinner table 711 to the upper end of the drive shaft 712a. The support means 713 includes a plurality of (three in the illustrated embodiment) support legs 713a and a plurality of (three in the illustrated embodiment) attached to the electric motor 712 by connecting the support legs 713a. ) Air cylinder 713b. The support means 713 configured as described above operates the air cylinder 713b to move the electric motor 712 and the spinner table 711 to the workpiece loading / unloading position, which is the upper position shown in FIG. 4, and the lower position shown in FIG. Position to the working position that is the position.

  The water receiving means 72 includes a cleaning water receiving container 721, three supporting legs 722 (two are shown in FIG. 3) that support the cleaning water receiving container 721, and driving of the electric motor 712. And a cover member 723 attached to the shaft 712a. As shown in FIGS. 4 and 5, the washing water receiving container 721 is composed of a cylindrical outer wall 721a, a bottom wall 721b, and an inner wall 721c. A hole 721d through which the drive shaft 712a of the electric motor 712 is inserted is provided at the center of the bottom wall 721b, and an inner wall 721c protruding upward from the periphery of the hole 721d is formed. Further, as shown in FIG. 3, the bottom wall 721b is provided with a drain port 721e, and a drain hose 724 is connected to the drain port 721e. The cover member 723 is formed in a disc shape, and includes a cover portion 723a that protrudes downward from the outer peripheral edge thereof. When the electric motor 712 and the spinner table 711 are positioned at the work position shown in FIG. 5, the cover member 723 configured as described above has a gap between the cover portion 723a and the inner wall 721c constituting the cleaning water receiving container 721. Is positioned to polymerize.

  The protective film coating and cleaning means 7 in the illustrated embodiment is a resin liquid supply mechanism that supplies a liquid resin to the surface (surface to be processed) of the semiconductor wafer 10 that is an object to be processed that is held by the spinner table 711. 74. The resin liquid supply mechanism 74 swings the resin supply nozzle 741 that supplies a liquid resin toward the surface (surface to be processed) of the unprocessed semiconductor wafer 10 held by the spinner table 711, and the resin supply nozzle 741. An electric motor 742 capable of normal rotation and reverse rotation is provided, and a resin supply nozzle 741 is connected to a resin liquid supply means (not shown). The resin supply nozzle 741 includes a nozzle portion 741a extending horizontally and a support portion 741b extending downward from the nozzle portion 741a, and the support portion 741b is provided on the bottom wall 721b constituting the washing water receiving container 721. It is disposed through an insertion hole (not shown). A seal member (not shown) that seals between the support portion 741b is attached to the periphery of an insertion hole (not shown) through which the support portion 741b of the resin supply nozzle 741 is inserted.

  The protective film coating / cleaning means 7 in the illustrated embodiment includes a cleaning water supply mechanism 75 for supplying cleaning water to the semiconductor wafer 10 which is a processed object held by the spinner table 711. Yes. The cleaning water supply mechanism 75 includes a cleaning water injection nozzle 751 that supplies cleaning water toward the wafer held by the spinner table 711, and an electric motor 752 that can rotate forward and reverse to swing the cleaning water injection nozzle 751. I have. The cleaning water jet nozzle 751 is composed of a nozzle portion 751a that extends horizontally and has a distal end bent downward, and a support portion 751b that extends downward from the base end of the nozzle portion 751a. The support portion 751b is the cleaning water. An insertion hole (not shown) provided in the bottom wall 721b constituting the receiving container 721 is inserted therethrough. The nozzle portion 751a of the cleaning water jet nozzle 751 includes a cleaning water passage and an air passage, the cleaning water passage is connected to the cleaning water supply means, and the air passage is connected to the air supply means. A sealing member (not shown) that seals between the support portion 751b and the support portion 751b is attached to the periphery of the insertion hole (not shown) through which the support portion 751b of the cleaning water jet nozzle 751 configured as described above is inserted.

  Further, the protective film coating / cleaning means 7 in the illustrated embodiment includes an air supply mechanism 76 for supplying air to the semiconductor wafer 10 which is a processed object held by the spinner table 711. Yes. The air supply mechanism 76 includes an air nozzle 761 that blows air toward the cleaned wafer held by the spinner table 711, and an electric motor 762 that can rotate forward and reverse to swing the air nozzle 761. The air nozzle 761 is connected to air supply means (not shown). The air nozzle 761 includes a nozzle portion 761a that extends horizontally and has a distal end bent downward, and a support portion 761b that extends downward from the base end of the nozzle portion 761a. The support portion 761b is the cleaning liquid collection container 721. Is inserted through an insertion hole (not shown) provided in the bottom wall 721b. A seal member (not shown) that seals between the support portion 761b is attached to the periphery of an insertion hole (not shown) through which the support portion 761b of the air nozzle 761 is inserted.

  The laser beam machine in the illustrated embodiment includes a dust discharge device 8 that discharges dust generated by irradiating a workpiece with a laser beam from a condenser 42 of the laser beam irradiation means 4 as shown in FIG. . The dust discharge device 8 includes a dust suction member 81 attached to the case 421 of the condenser 42, one end connected to the dust suction member 81, a duct 82, and an exhaust means 83 connected to the other end of the duct 82. It has. The dust suction member 81 includes an annular bottom portion 811 having a fitting hole 811a for fitting with the case 421 of the condenser 42, a cylindrical mounting portion 812 standing from the inner periphery of the annular bottom portion 811, A suction part 813 is formed to hang from the outer peripheral edge of the annular bottom plate 811 and has an opening 813a at the lower end. The opening 813a is opened toward the irradiation part of the laser beam emitted from the condenser 42. . One end of the duct 82 is connected to a hole 811 b provided in the bottom 811 of the dust suction member 81. On the side wall of the duct 82, a first transmission window 84 and a second transmission window 85 that transmit light are disposed to face each other. As shown in FIG. 7, the first transmission window 84 and the second transmission window 85 are each composed of window frames 841 and 851, and transparent members 842 and 852 fitted in the window frames 841 and 851, respectively. Window frames 841 and 851 are fitted into holes 821 and 822 provided in the side wall of duct 82, respectively. The exhaust means 83 includes a first filter 831 and a second filter 832 that are disposed at intervals, and a blower 833 that is disposed between the first filter 831 and the second filter 832. The first filter 831 is connected to the other end of the duct 82. The duct 82 is detachably mounted and is configured so that the inner surface can be easily cleaned.

  The dust discharge device 8 in the illustrated embodiment includes a light emitting means 86 that is disposed on the side of the first transmission window 84 and emits light toward the second transmission window 85 through the transparent member 842, and the light emission means. Light receiving means 87 for receiving the light emitted by 86 through the transparent member 852, and control means 88 for determining the degree of dust deposited on the inner surface of the duct 82 based on the amount of light received by the light receiving means 87. ing. The light emitting means 86 is composed of a laser light emitting diode (LED) and irradiates light toward the transparent member 842 of the first transmission window 84. The light receiving means 87 sends a voltage signal corresponding to the amount of received light to the control means 88. The light receiving means 87 outputs a large amount of received light when dust is not attached to the transparent members 842 and 852 of the first transmission window 84 and the second transmission window 85 constituting a part of the duct 82. The value of the voltage signal is high. On the other hand, when dust adheres to and accumulates on the transparent members 842 and 852 of the first transmission window 84 and the second transmission window 85 constituting a part of the duct 82, the light receiving means 87 outputs because the amount of received light decreases. The value of the voltage signal is low. Based on the voltage signal from the light receiving means 87, the control means 88 determines that a predetermined amount of dust has accumulated in the duct 82 if the voltage value reaches a predetermined value or less, and the display means 881 has dust in the duct 82. It shows that it was quantitatively deposited. The operator sees the message displayed on the display means 881 and removes the dust accumulated in the duct 82 for cleaning. Therefore, it is possible to prevent a fire that occurs when sparks scattered by irradiation of a laser beam, high-temperature debris, etc. ignite dust accumulated in a predetermined amount or more in the duct 82.

The laser processing apparatus 1 equipped with the protective film coating and cleaning means 7 and the dust discharge device 8 described above is configured as described above, and the operation thereof will be described below.
As shown in FIG. 1, an unprocessed semiconductor wafer 10 (hereinafter simply referred to as “semiconductor wafer 10”) supported on an annular frame F via a protective tape T is a cassette 11 with a surface 10a as a processing surface facing upward. In a predetermined position. The unprocessed semiconductor wafer 10 accommodated in a predetermined position of the cassette 11 is positioned at the unloading position by the cassette table 111 moving up and down by an elevating means (not shown). Next, the wafer carry-out / carry-in means 13 is advanced and retracted, and the semiconductor wafer 10 positioned at the carry-out position is carried out to the alignment means 12 disposed in the temporary placement portion 12a. The semiconductor wafer 10 carried out to the alignment means 12 is aligned at a predetermined position by the alignment means 12. Next, the unprocessed semiconductor wafer 10 aligned by the alignment means 12 is placed on the suction chuck 711a of the spinner table 711 constituting the protective film coating / cleaning means 7 by the turning operation of the first wafer transport means 14. It is conveyed and sucked and held by the suction chuck 711a (wafer holding step). At this time, the spinner table 711 is positioned at the workpiece loading / unloading position shown in FIG. 4, and the resin supply nozzle 741, the washing water injection nozzle 751 and the air nozzle 761 are as shown in FIG. 3 and FIG. 711 is positioned at a standby position separated from above 711.

  If a wafer holding process is performed in which the semiconductor wafer 10 before processing is held on the spinner table 711 of the protective film coating and cleaning means 7, the protective film that covers the surface 10 a that is the processing surface of the semiconductor wafer 10 is covered. A coating process is performed. That is, the electric motor 742 of the resin liquid supply mechanism 74 is operated and the nozzle portion 741a of the resin supply nozzle 741 is the surface to be processed of the semiconductor wafer 10 held on the spinner table 711 as shown in FIG. It is positioned above the center of the surface 10a. Then, a predetermined amount of the liquid resin 110 is dropped onto the central portion of the surface 10a, which is the processing surface of the semiconductor wafer 10 held by the spinner table 711, by operating a resin liquid supply means (not shown) (liquid resin dropping step). The amount of the liquid resin 110 to be dropped in this liquid resin dropping step may be 2 milliliters when the diameter of the semiconductor wafer 10 that is a workpiece is 200 mm. The liquid resin 110 dropped in the liquid resin dropping step is preferably a water-soluble resist such as PVA (Poly Vinyl Alcohol), PEG (Poly Ethylene Glycol), or PEO (Poly Ethylene Oxide).

  When the above-described liquid resin dropping step is performed, the control means 88 operates the electric motor 712 of the spinner table mechanism 71 as shown in FIG. 8B to bring the spinner table 711 to 500 rpm in the direction indicated by the arrow A. Rotates for 15 seconds at rotational speed. As a result, the liquid resin 110 dropped by the centrifugal force accompanying the rotation of the semiconductor wafer 10 is caused to flow toward the outer periphery, whereby the surface 10a, which is the work surface of the semiconductor wafer 10, has a thickness of 0.2 to 1.0 μm. A protective film 120 is formed (protective film coating step).

  As described above, when the protective film coating process for coating the protective film 120 on the surface 10a that is the processed surface of the semiconductor wafer 10 is performed, the spinner table 711 is positioned at the workpiece loading / unloading position shown in FIG. Then, the suction holding of the semiconductor wafer 10 held on the spinner table 711 is released. The semiconductor wafer 10 on the spinner table 711 is transported onto the suction chuck 32 of the chuck table 3 by the second wafer transport means 15 and sucked and held by the suction chuck 32. The chuck table 3 that sucks and holds the semiconductor wafer 10 in this way is positioned immediately below the image pickup means 5 disposed in the laser beam irradiation means 4 by a processing feed means (not shown).

  When the chuck table 3 is positioned immediately below the image pickup means 5, a street 101 formed in a predetermined direction on the semiconductor wafer 10 by the image pickup means 5 and a control means (not shown), and a laser beam irradiation means for irradiating the laser beam along the street 101 Image processing such as pattern matching for performing alignment with the four condensers 42 is performed, and alignment of the laser beam irradiation position is performed. Similarly, alignment of the laser beam irradiation position is performed on the street 101 formed in the semiconductor wafer 10 and extending in a direction perpendicular to the predetermined direction. At this time, the protective film 120 is formed on the surface 10a where the street 101 of the semiconductor wafer 10 is formed. However, if the protective film 120 is not transparent, it can be imaged with infrared rays and aligned from the surface.

  If the street 101 formed on the semiconductor wafer 10 held on the chuck table 3 is detected as described above and the laser beam irradiation position is aligned, as shown in FIG. The chuck table 3 is moved to a laser beam irradiation region where the condenser 42 of the laser beam application means 4 for irradiating the laser beam is located, and a predetermined street 101 is positioned immediately below the condenser 42. At this time, as shown in FIG. 9A, the semiconductor wafer 10 is positioned such that one end of the street 101 (the left end in FIG. 9A) is located directly below the condenser 42.

  On the other hand, the air blower 833 constituting the exhaust means 83 of the dust discharge device 8 is operated. As a result, the air in the vicinity of the opening 813a of the dust suction member 81 constituting the dust discharging device 8 is sucked through the duct 82 and the first filter 831 and discharged through the second filter 832, so that the vicinity of the opening 813a is Negative pressure.

  The chuck table 3 is indicated by an arrow X1 in FIG. 9A while irradiating a pulse laser beam from the condenser 42 of the laser beam irradiation means 4 in a state where the blower 833 of the dust discharge device 8 is operated in this manner. Move in the direction at a predetermined machining feed rate. Then, as shown in FIG. 9B, when the other end of the street 101 (the right end in FIG. 9B) reaches a position directly below the condenser 42, the irradiation of the pulse laser beam is stopped and the chuck table 3 is stopped. That is, the movement of the semiconductor wafer 10 is stopped. In this laser processing groove forming step, the condensing point P of the pulse laser beam is matched with the vicinity of the surface of the street 101.

  By performing the laser processing groove forming step described above, a laser processing groove 140 is formed on the street 101 of the semiconductor wafer 10 as shown in FIG. At this time, even if debris 150 is generated by irradiation with a laser beam as shown in FIG. 10, the debris 150 is blocked by the protective film 120 and does not adhere to the device 102, the bonding pad, or the like. Then, the above-described laser processing groove forming process is performed on all the streets 101 of the semiconductor wafer 10.

In addition, the said laser processing groove | channel formation process is performed on the following processing conditions, for example.
Laser light source: YVO4 laser or YAG laser Wavelength: 355 nm
Repetition frequency: 50 kHz
Output: 4W
Condensing spot diameter: 9.2 μm
Processing feed rate: 200 mm / sec

  In addition, when the above-mentioned laser processing groove forming process is performed, dust such as debris is generated by the irradiation of the laser beam. The dust such as debris generated in this way is negative pressure in the vicinity of the opening 813a of the dust suction member 81 constituting the dust discharge device 8 by the operation of the dust discharge device 8 as described above. The air is sucked from the suction member 81 to the exhaust means 83 through the duct 82. In this way, dust such as debris sucked into the exhaust means 83 is captured by the first filter 831 and the second filter 832. As described above, dust such as debris generated by the laser beam irradiation adheres to and accumulates on the inner surface of the duct 82 when the dust suction member 81 sucks the dust through the duct 82 through the exhaust means 83. Accordingly, dust adheres to and accumulates on the transparent members 842 and 852 of the first transmission window 84 and the second transmission window 85 that constitute a part of the duct 82. As described above, when dust adheres to and accumulates on the transparent members 842 and 852 of the first transmission window 84 and the second transmission window 85 as described above, the value of the voltage signal output from the light receiving means 87 decreases, as described above. When the voltage value reaches a predetermined value or less, the control means 88 determines that a predetermined amount of dust has accumulated in the duct 82 and displays on the display means 881 that a predetermined amount of dust has accumulated in the duct 82. The operator sees the message displayed on the display means 881 and removes the dust accumulated in the duct 82 for cleaning. Therefore, it is possible to prevent a fire that occurs when sparks scattered by irradiation of a laser beam, high-temperature debris, etc. ignite dust accumulated in a predetermined amount or more in the duct 82.

  If the above-described laser processing groove forming process is performed along all the streets 101 of the semiconductor wafer 10, the chuck table 3 holding the semiconductor wafer 10 is returned to the position where the semiconductor wafer 10 is first sucked and held. Here, the suction holding of the semiconductor wafer 10 is released. Then, the semiconductor wafer 10 is transported onto the suction chuck 711a of the spinner table 711 constituting the protective film coating / cleaning means 7 by the second wafer transport means 15, and sucked and held by the suction chuck 711a. At this time, the resin supply nozzle 741, the air nozzle 751, and the cleaning water nozzle 761 are positioned at a standby position separated from the upper side of the spinner table 711 as shown in FIGS. 3 and 4.

  If the processed semiconductor wafer 10 is held on the spinner table 711 of the protective film coating and cleaning means 7, a cleaning process is executed. That is, as shown in FIG. 5, the spinner table 711 is positioned at the work position, and the electric motor 752 of the cleaning water supply mechanism 75 is operated to hold the nozzle portion 751a of the cleaning water injection nozzle 751 on the spinner table 711. Positioning above the rotation center of the wafer 10 (injection nozzle positioning step). The cleaning water supply means (not shown) is operated while rotating the spinner table 711 in the direction indicated by the arrow B at a rotation speed of 700 rpm, for example, to supply 0.2 Mpa of cleaning water to the cleaning water jet nozzle 751 and not shown. For example, 0.3 Mpa of air is supplied to the cleaning water jet nozzle 751 by operating the air supply means. As a result, the cleaning water is ejected from the nozzle portion 751a of the cleaning water injection nozzle 751 by the air pressure. Note that the amount of cleaning water sprayed from the nozzle portion 751a of the cleaning water spray nozzle 751 is set to 2 liters / minute in the illustrated embodiment. At this time, the nozzle portion 751 a of the cleaning water spray nozzle 751 is stopped at a position above the rotation center of the semiconductor wafer 10 for 1 to 3 seconds, and the cleaning water is sprayed to the rotation center of the semiconductor wafer 10. If the cleaning water is sprayed to the rotation center of the semiconductor wafer 10 for 1 to 3 seconds in this way, the cleaning water injection nozzle 751 is swung by operating the electric motor 752 of the cleaning water supply mechanism 75, and the nozzle portion 751a is moved to the semiconductor. The wafer 10 is moved from the center of rotation toward the outer periphery (cleaning step). In this way, in the cleaning process, the cleaning water sprayed from the nozzle portion 751a of the cleaning water spray nozzle 751 moves from the rotation center of the semiconductor wafer 10 toward the outer periphery, so the cleaning spray sprayed to the rotation center of the semiconductor wafer 10 is performed. The water moves from the rotation center of the semiconductor wafer 10 toward the outer periphery due to the centrifugal force of the rotating semiconductor wafer 10 and scatters while dissolving the protective film 120 coated on the surface 10 a of the semiconductor wafer 10. The protective film 120 can be efficiently washed away by one movement of the nozzle portion 751a of the washing water jet nozzle 751 without causing stagnation in the center, and the debris 150 generated during laser processing can also be removed.

  When the above-described cleaning process is completed, a drying process is performed. That is, the cleaning water jet nozzle 751 is positioned at the standby position, and the spinner table 711 is rotated at a rotational speed of, for example, 3000 rpm for about 15 seconds. At this time, the electric motor 762 of the air supply mechanism 76 is operated so that the nozzle portion 761a of the air nozzle 761 is positioned above the center portion of the surface 10a that is the surface to be processed of the semiconductor wafer 10 held by the spinner table 711, and air supply is performed. The mechanism 76 is operated to supply 200 milliliters / second of air from the nozzle portion 761a of the air nozzle 761 to the surface 10a that is the processing surface of the semiconductor wafer 10, and the nozzle portion 761a of the air nozzle 761 is swung within a required angle range. It is desirable that

  As described above, when cleaning and drying of the processed semiconductor wafer 10 are completed, the rotation of the spinner table 711 is stopped and the air nozzle 761 of the air supply mechanism 76 is positioned at the standby position. Then, the spinner table 711 is positioned at the workpiece loading / unloading position shown in FIG. 4 and the suction holding of the semiconductor wafer 10 held on the spinner table 711 is released. Next, the processed semiconductor wafer 10 on the spinner table 711 is carried out by the first wafer transfer means 14 to the alignment means 12 disposed in the temporary placement portion 12a. The processed semiconductor wafer 10 unloaded to the alignment means 12 is stored in a predetermined position of the cassette 11 by the wafer unloading means 13.

DESCRIPTION OF SYMBOLS 1: Laser processing machine 2: Apparatus housing 3: Chuck table 4: Laser beam irradiation means 41: Laser beam oscillation means 42: Condenser 5: Imaging means 6: Display means 7: Protection film coating and washing means 71: Spinner table mechanism 711 : Spinner table 712: Electric motor 72: Water receiving means 74: Resin liquid supply mechanism 741: Resin supply nozzle 75: Washing water supply mechanism 751: Washing water injection nozzle 76: Air supply mechanism 761: Air nozzle 8: Dust discharging device 81 : Dust suction member 82: duct 83: exhaust means 831: first filter 832: second filter 833: blower 84: first transmission window 85: second transmission window 86: light emission means 87: light reception means 88: Control means 881: Display means 10: Semiconductor wafer 11: Cassette 12: Positioning 13: Wafer carry-in / carry-in means 14: First wafer transfer means 15: Second wafer transfer means
F: Ring frame
T: Protective tape

Claims (1)

In a dust discharge device for discharging dust generated by irradiating a workpiece with a laser beam from a condenser of a laser beam irradiation means,
A dust suction member that opens toward the irradiation part of the laser beam emitted from the light collector; a duct having one end connected to the dust suction member; and an exhaust means connected to the other end of the duct. And
A first transmission window and a second transmission window made of a transparent member that transmits light are disposed on the side wall of the duct so as to face each other.
A light emitting means for emitting light toward the second transmission window through the first transmission window; a light receiving means for receiving light emitted by the light emission means through the second transmission window; and Control means for determining the degree of accumulation of dust adhering to the inner surface of the duct based on the light quantity of the light,
A dust discharge device characterized by that.

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