JP2007201178A - Laser processing equipment - Google Patents

Abstract

The present invention provides a laser processing apparatus that has a function of covering a processed surface of a workpiece with a protective film and a function of cleaning the protective film after laser processing and can improve processing efficiency.
A chuck table, a laser beam irradiation unit, a workpiece storage cassette mounting table, and a loading / unloading means for unloading and loading a workpiece from a cassette on the cassette mounting table are unloaded. In a laser processing apparatus comprising a temporary work table 15 and a transport means for transporting the work to the chuck table, the unprocessed work carried on the temporary table is transported to the chuck table. Protective film forming means 7 that is disposed in the first conveyance path and coats the workpiece before processing with a protective film, and a second workpiece that is transferred to the temporary placement table after the workpiece held by the chuck table is processed. A cleaning means 8 is provided for cleaning and removing a protective film disposed on the conveyance path and coated on the processed workpiece.
[Selection] Figure 1

Description

  The present invention relates to a laser processing apparatus that performs predetermined processing by irradiating a predetermined region of a workpiece with a laser beam.

  As is well known to those skilled in the art, in a semiconductor device manufacturing process, a semiconductor in which a plurality of devices such as ICs and LSIs are formed in a matrix by a laminated body in which an insulating film and a functional film are laminated on the surface of a semiconductor substrate such as silicon. A wafer is formed. In the semiconductor wafer formed in this way, the above devices are partitioned by dividing lines called streets, and individual semiconductor chips are manufactured by cutting along the streets. In addition, an optical device wafer in which a plurality of regions are defined by streets formed in a lattice pattern on the surface of a sapphire substrate or the like, and an optical device in which a gallium nitride compound semiconductor or the like is stacked in the partitioned region is It is divided into individual light-emitting diodes, laser diodes and other optical devices along the street, and is widely used in electrical equipment.

Such cutting along the streets of a wafer such as a semiconductor wafer or an optical device wafer is usually performed by a cutting device called a dicer. The cutting apparatus includes a chuck table for holding a wafer as a workpiece, a cutting means for cutting the wafer held by the chuck table, and a moving means for relatively moving the chuck table and the cutting means. It has. The cutting means includes a rotating spindle that is rotated at a high speed and a cutting blade attached to the spindle. The cutting blade is composed of a disk-shaped base and an annular cutting edge mounted on the outer peripheral portion of the side surface of the base. The cutting edge is fixed by electroforming diamond abrasive grains having a grain size of about 3 μm, for example, with a thickness of 20 μm. It is formed to the extent. When the wafer is cut with such a cutting blade, chips and cracks are generated on the cut surface of the cut chips, and the width of the street is formed to be about 50 μm in consideration of the effects of the chips and cracks. However, when the size of the semiconductor chip is reduced, the proportion of streets in the chip increases, which causes a decrease in productivity. Further, in cutting with a cutting blade, there is a problem that the feed rate is limited and the chip is contaminated by the generation of cutting waste.

In recent years, inorganic films such as SiOF and BSG (SiOB), polyimide films, and parylene films are formed on the surface of a semiconductor wafer body such as a silicon wafer in order to form devices such as ICs and LSIs more finely. A semiconductor wafer in a form in which a low dielectric constant insulator (Low-k film) made of an organic film such as a polymer film is laminated, or a semiconductor wafer provided with a metal pattern called a test element group (Teg) It has been put into practical use. When a semiconductor wafer in a form in which a low dielectric constant insulator (Low-k film) is laminated is cut along a street with a cutting blade, there is a problem that the low dielectric constant insulator is peeled off. Further, when a semiconductor wafer having a metal pattern called a test element group (Teg) is cut along a street with a cutting blade, burrs are generated because the metal pattern is formed of a sticky metal such as copper. There is a problem.

On the other hand, in recent years, as a method of dividing a plate-like workpiece such as a semiconductor wafer, a laser processing groove is formed by irradiating a pulse laser beam along a street formed on the workpiece, and along this laser processing groove. A method of cleaving with a mechanical braking device has been proposed. (For example, refer to Patent Document 1.)
JP-A-10-305420

  Laser processing can increase the processing speed as compared with cutting processing, and can relatively easily process even a wafer made of a material having high hardness such as sapphire. In addition, the method of forming a laser-processed groove by irradiating a laser beam can solve the problem that the low dielectric constant insulator layer is peeled off, and can also solve the problem that burrs are generated. However, when a laser beam is irradiated along the street of the wafer, the thermal energy concentrates on the irradiated area and debris is generated, and this debris adheres to the surface of the chip and has a new problem of deteriorating the quality of the chip. Arise.

In order to solve the problem caused by the debris, there has been proposed a laser processing method 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, see Patent Document 2.)
JP 2004-188475 A

However, it is possible to install a protective film forming device that coats the processing surface of the workpiece and a laser processing device that irradiates the workpiece with a laser beam through the protective coating. It is not always efficient from the viewpoint of transporting objects between devices.
Therefore, a laser processing apparatus has been proposed that includes a protective film forming and cleaning means for covering the processed surface of the workpiece with a protective film and cleaning the protective film after laser processing (for example, see Patent Document 3).
JP 2004-322168 A

  Thus, the laser processing apparatus disclosed in the above publication has a function for the protective film forming and cleaning means to coat the protective film on the processed surface of the workpiece and to clean the protective film after the laser processing. Therefore, the protective film cannot be coated on the next workpiece while the workpiece after laser processing is being cleaned. Therefore, since the protective film coating process can only be performed on the next workpiece after the protective film coating process, the laser processing process, and the cleaning process are performed on one workpiece, the processing efficiency is improved. Is bad.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is that it has a function of covering the processed surface of the workpiece with a protective film and a function of cleaning the protective film after laser processing, and processing efficiency. It is providing the laser processing apparatus which can make favorable.

In order to solve the above main technical problem, according to the present invention, a chuck table for holding a workpiece, a laser beam irradiation means for irradiating a workpiece with a laser beam to the workpiece held by the chuck table, and a workpiece are accommodated. A cassette placement table on which the cassette is placed, a carry-in / out means for carrying out and carrying in the work piece from the cassette placed on the cassette placement table, and a work piece carried out by the carry-in / out means. In a laser processing apparatus comprising a temporary placement table for temporary placement, and a transport means for transporting a workpiece between the temporary placement table and the chuck table,
Protective film forming means that is disposed in the first transport path for transporting the workpiece before being unloaded to the temporary table to the chuck table, and that covers the processed surface of the workpiece before machining. When,
The protective film coated on the processed surface of the processed workpiece is removed by washing in the second transfer path for transferring the processed workpiece held on the chuck table to the temporary table. Cleaning means,
A laser processing apparatus is provided.

  The conveying means conveys the workpiece to be processed, which has been carried out to the temporary placement table, to the protective film forming means, and conveys the processed workpiece cleaned by the cleaning means to the temporary placement table. The first transporting means and the unprocessed workpiece coated with the protective coating by the protective coating forming means are transported to the chuck table and the processed workpiece held on the chuck table is cleaned with the cleaning means. And a second transport means for transporting to the center.

  Since the laser processing apparatus according to the present invention includes the protective film forming unit and the cleaning unit, the workpiece to be processed next is performed while the cleaning step is performed on the workpiece on which the laser beam irradiation step has been performed. Since an object can be conveyed to a protective film formation means and a protective film coating process can be implemented, production efficiency can be improved.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a laser processing apparatus configured 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 processing apparatus constructed according to the present invention.
The laser processing apparatus shown in FIG. 1 includes a substantially rectangular parallelepiped apparatus housing 2. In the apparatus housing 2, a chuck table 3 as a workpiece holding means for holding a workpiece is disposed so as to be movable in a direction indicated by an arrow X that is a machining feed direction. 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. For example, a disk-shaped semiconductor 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 33 for fixing an annular frame described later.

  The illustrated laser processing apparatus includes a laser beam irradiation means 4 that irradiates a workpiece held on the chucking chuck 32 of the chuck table 3 with a laser beam. The laser beam irradiation means 4 includes a cylindrical casing 41 disposed substantially horizontally. In the casing 41, a pulse laser beam oscillation means including a pulse laser beam oscillator or a repetition frequency setting means (not shown) including a YAG laser oscillator or a YVO4 laser oscillator is disposed. A condenser 42 for condensing the pulse laser beam oscillated from the pulse laser beam oscillating means is attached to the tip of the casing 41.

  The illustrated laser processing apparatus images the surface of the workpiece held on the suction chuck 32 of the chuck table 3 and defines a region to be processed by the laser beam irradiated from the condenser 42 of the laser beam irradiation means 4. An imaging means 5 for detection is provided. In the illustrated embodiment, the imaging unit 5 includes an infrared illumination unit that irradiates a workpiece with infrared rays, and an infrared ray that is irradiated by the infrared illumination unit, in addition to a normal imaging device (CCD) that captures visible light. And an imaging device (infrared CCD) that outputs an electrical signal corresponding to the infrared rays captured by the optical system, and sends the captured image signal to a control means (not shown). The wafer dividing apparatus shown in the figure includes a display unit 6 for displaying an image captured by the imaging unit 5.

  The illustrated laser processing apparatus includes a cassette mounting portion 13a on which a cassette that accommodates a semiconductor wafer 10 that is a workpiece is mounted. A cassette table 131 is arranged on the cassette mounting portion 13a so as to be movable up and down by lifting means (not shown). The cassette 13 is mounted on the cassette table 131. The semiconductor wafer 10 is affixed to the surface of a protective tape 12 attached to an annular frame 11 and is accommodated in the cassette 13 while being supported by the annular frame 11 via the protective tape 12. As shown in FIG. 8, the semiconductor wafer 10 is divided into a plurality of regions by a plurality of division lines 101 formed in a lattice pattern on the surface 10a, and devices 102 such as ICs, LSIs, etc. are formed in the divided regions. Is formed. As shown in FIG. 1, the semiconductor wafer 10 configured as described above is attached to the protective tape 12 mounted on the annular frame 11 with the front surface 10 a facing upward.

  The illustrated laser processing apparatus includes a workpiece unloading / unloading means 14 for unloading the semiconductor wafer 10 before processing stored in the cassette 13 and loading the processed semiconductor wafer 10 into the cassette 13, and unloading the workpiece. Temporary placement table 15 for temporarily placing unprocessed semiconductor wafer 10 unloaded by carry-in means 14 and a first transport path for transporting unprocessed semiconductor wafer 10 unloaded to temporary placement table 15 to chuck table 3. A protective film forming means 7 that covers the processed surface of the semiconductor wafer 10 that is disposed and before processing, and a second transport that transports the processed semiconductor wafer 10 held on the chuck table 3 to the temporary placement table 15. A cleaning means 8 is provided for cleaning and removing the protective film disposed on the path and coated on the processed surface of the processed semiconductor wafer 10. There. It is important that the first transport path and the second transport path are different from each other. The illustrated laser processing apparatus transports the unprocessed semiconductor wafer 10 transported to the temporary placement table 15 to the protective film forming means 7 and the processed semiconductor wafer 10 cleaned by the cleaning means 8 temporarily. The semiconductor wafer 10 before processing, which is covered with the protective film forming means 7, is transferred to the chuck table 3, and the processed semiconductor wafer held by the chuck table 3 is transferred to the chuck table 3. Second transport means 17 for transporting 10 to the cleaning means 8 is provided.

Next, the protective film forming means 7 will be described with reference to FIGS.
The protective film forming means 7 in the illustrated embodiment includes a spinner table mechanism 71 and a spinner table accommodation 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 that rotationally drives the spinner table 711, and a support mechanism 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 spinner table 711 is provided with a clamp 714 for fixing the annular frame 11. The electric motor 712 connects the spinner table 711 to the upper end of the drive shaft 712a. The support mechanism 713 includes a plurality of support legs 713a (three in the illustrated embodiment) and a plurality of support legs 713a that are connected to the electric motor 712 by connecting the support legs 713a (three in the illustrated embodiment). ) Air cylinder 713b. The support mechanism 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 illustrated in FIG. 3, and the lower position illustrated in FIG. Position to the working position that is the position.

  The spinner table storage means 72 includes a storage container 721, three support legs 722 (two are shown in FIG. 2) that support the storage container 721, and a drive shaft 712a of the electric motor 712. And a cover member 723 attached. As shown in FIGS. 3 and 4, the storage container 721 includes 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. 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. 4, the cover member 723 configured in this way is overlapped with a gap on the outer side of the inner wall 721 c that constitutes the storage container 721. Positioned to do.

  The protective film forming means 7 shown in the figure includes a resin liquid supply means 74 for supplying a liquid resin to the surface of the semiconductor wafer 10 that is a workpiece to be processed, which is held by the spinner table 711. The resin liquid supply means 74 is a resin liquid supply nozzle 741 that supplies a liquid resin toward the surface of the unprocessed wafer held by the spinner table 711, and can be rotated forward and backward to swing the resin liquid supply nozzle 741. An electric motor 742 is provided, and a resin liquid supply nozzle 741 is connected to a resin liquid supply source (not shown). The resin liquid supply nozzle 741 is composed of a nozzle portion 741a that extends horizontally and has a distal end bent downward, and a support portion 741b that extends downward from the base end of the nozzle portion 741a, and the support portion 741b is the container. An insertion hole (not shown) provided in the bottom wall 721b constituting the 721 is inserted and connected to a liquid resin liquid supply source (not shown). Further, a seal member (not shown) that seals between the support portion 741b is mounted on the periphery of an insertion hole (not shown) through which the support portion 741b of the resin liquid supply nozzle 741 is inserted.

Next, the cleaning means 8 will be described with reference to FIGS.
The cleaning means 8 in the illustrated embodiment includes a spinner table mechanism 81 and a cleaning water receiving means 82 disposed so as to surround the spinner table mechanism 81. Similar to the spinner table mechanism 71 of the protective film forming means 7, the spinner table mechanism 81 is capable of moving the spinner table 811, the electric motor 812 that rotationally drives the spinner table 811, and the electric motor 812 up and down. A support mechanism 813 for supporting is provided. The spinner table 811 includes a suction chuck 811a formed of a porous material, and the suction chuck 811a communicates with suction means (not shown). Accordingly, the spinner table 811 holds the wafer on the suction chuck 811 by placing a wafer as a workpiece on the suction chuck 811a and applying a negative pressure by suction means (not shown). The spinner table 811 is provided with a clamp 814 for fixing the annular frame 11. The electric motor 812 connects the spinner table 811 to the upper end of the drive shaft 812a. The support mechanism 813 includes a plurality of (three in the illustrated embodiment) support legs 813a and a plurality of (three in the illustrated embodiment) attached to the electric motor 812 by connecting the support legs 813a. ) Air cylinder 813b. The support mechanism 813 configured as described above operates the air cylinder 813b to move the electric motor 812 and the spinner table 811 to the workpiece loading / unloading position, which is the upper position illustrated in FIG. 6, and the lower position illustrated in FIG. Position to the working position that is the position.

  The cleaning water receiving means 82 includes a cleaning water receiving container 821, three supporting legs 822 (two are shown in FIG. 5) for supporting the cleaning water receiving container 821, and the electric motor 812. And a cover member 823 attached to the drive shaft 812a. As shown in FIGS. 6 and 7, the washing water receiving container 821 includes a cylindrical outer wall 821a, a bottom wall 821b, and an inner wall 821c. A hole 821d through which the drive shaft 812a of the electric motor 812 is inserted is provided at the center of the bottom wall 821b, and an inner wall 821c protruding upward from the periphery of the hole 821d is formed. As shown in FIG. 6, the bottom wall 821b is provided with a drain port 821e, and a drain hose 824 is connected to the drain port 821e. The cover member 823 is formed in a disc shape and includes a cover portion 823a protruding downward from the outer peripheral edge thereof. When the electric motor 812 and the spinner table 811 are positioned at the work position shown in FIG. 7, the cover member 823 configured as described above has a gap between the cover portion 823 a and the inner wall 821 c that constitutes the cleaning water receiving container 821. Is positioned to polymerize.

  The illustrated cleaning means 8 includes a cleaning water supply means 84 for cleaning a wafer which is a processed workpiece held on the spinner table 811. The cleaning water supply means 84 includes a cleaning water nozzle 841 that ejects cleaning water toward the processed wafer held by the spinner table 811, and an electric motor 842 that can rotate forward and reverse to swing the cleaning water nozzle 841. The cleaning water nozzle 841 is connected to a cleaning water supply source (not shown). The cleaning water nozzle 841 includes a nozzle portion 841a that extends horizontally and has a distal end bent downward, and a support portion 841b that extends downward from the base end of the nozzle portion 841a. The support portion 841b receives the cleaning water receiver. An insertion hole (not shown) provided in a bottom wall 821b constituting the container 821 is inserted and connected to a cleaning water supply source (not shown). A seal member (not shown) that seals between the support portion 841b and the support hole 841b is attached to the periphery of the insertion hole (not shown) through which the support portion 841b of the cleaning water nozzle 841 is inserted.

  The illustrated cleaning unit 8 includes an air supply unit 85 that blows air onto the surface of the cleaned wafer held by the spinner table 811. The air supply means 85 includes an air nozzle 851 that blows air toward the wafer held by the spinner table 811, and an electric motor (not shown) that can rotate forward and reverse to swing the air nozzle 851. The air nozzle 851 is connected to an air supply source (not shown). The air nozzle 851 includes a nozzle portion 851a that extends horizontally and has a distal end bent downward, and a support portion 851b that extends downward from the base end of the nozzle portion 851a. The support portion 851b is the above-described washing water receiving container. An insertion hole (not shown) provided in the bottom wall 821b constituting the 821 is inserted and connected to an air supply source (not shown). A seal member (not shown) that seals between the support portion 851b and the support hole 851b is attached to the periphery of an insertion hole (not shown) through which the support portion 851b of the air nozzle 851 is inserted.

Next, the first conveying means 16 and the second conveying means 17 will be described with reference to FIG.
The first transport unit 16 is disposed at an equidistant position with respect to the temporary placement table 15, the protective film forming unit 7, and the cleaning unit 8. The first conveying means 16 may have the same configuration as a generally used conveying means. The holding means 161 for sucking and holding the annular frame 11 and the holding means 161 can be moved up and down and swiveled. It comprises support means 162 that supports it. The first transport means 16 configured in this manner is configured to transfer the unprocessed semiconductor wafer 10 (pasted to the surface of the protective tape 12 mounted on the annular frame 11) unloaded to the temporary table 15. The processed semiconductor wafer 10 (attached to the surface of the protective tape 12 attached to the annular frame 11) cleaned by the cleaning means 8 and conveyed to the protective film forming means 7 is conveyed to the temporary placement table 15. To do.

  The second conveying means 17 is disposed at an equidistant position with respect to the chuck table 3, the protective film forming means 7 and the cleaning means 8. The second conveying means 17 may have substantially the same configuration as the first conveying means 16, and the holding means 171 for sucking and holding the annular frame 11 and the holding means 171 can be moved up and down. And supporting means 172 that supports the vehicle in a pivotable manner. The second conveying means 17 configured as described above is adhered to the surface of the semiconductor wafer 10 before processing (protective tape 12 attached to the annular frame 11) covered with the protective film by the protective film forming means 7. The processed semiconductor wafer 10 held on the chuck table 3 (attached to the surface of the protective tape 12 attached to the annular frame 11) held by the chuck table 3 to the cleaning means 8. Transport.

The illustrated laser processing apparatus 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 a semiconductor wafer 10) supported on an annular frame 11 via a protective tape 12 is formed on the cassette 13 with the surface 10a as a processing surface facing upward. Housed in place. The unprocessed semiconductor wafer 10 accommodated in a predetermined position of the cassette 13 is positioned at the unloading position when the cassette table 131 moves up and down by lifting means (not shown). Next, the workpiece unloading / carrying means 14 moves forward and backward, and the semiconductor wafer 10 positioned at the unloading position is unloaded onto the temporary table 15 disposed in the temporary table 15a. The semiconductor wafer 10 carried out to the temporary placement table 15 is subjected to a center alignment process for aligning the center position. Next, the unprocessed semiconductor wafer 10 centered by the temporary placement table 15 is sucked and held by the holding means 161 of the first transport means 16 and the protective film forming means is rotated by the support means 162 as a center. 7 is sucked and held on the suction chuck 711a of the spinner table 711 that constitutes 7 (wafer holding step). In addition, the annular frame 11 is fixed by a clamp 714. At this time, the spinner table 711 is positioned at the workpiece loading / unloading position shown in FIG. 3, and the resin supply nozzle 741 is positioned at the standby position spaced apart from above the spinner table 711 as shown in FIGS. ing.

  When the wafer holding step of holding the unprocessed semiconductor wafer 10 on the spinner table 711 of the protective film forming means 7 is performed, the spinner table 711 is positioned at the work position shown in FIG. The liquid supply nozzle 741 is swung around the support portion 741b, and the tip of the nozzle portion 741a is positioned above the central region of the surface 10a that is the processing surface of the semiconductor wafer 10 held on the spinner table 711. Next, the electric motor 712 is operated to rotate the spinner table 711 (see FIG. 2) at a rotation speed of 300 to 1000 rpm. Accordingly, the semiconductor wafer 10 held on the spinner table 711 (the state of being attached to the surface of the protective tape 12 attached to the annular frame 11) is rotated in the direction indicated by the arrow 70 in FIG. With the semiconductor wafer 10 rotating in this way, a predetermined amount of the liquid resin 100 is provided from the nozzle portion 741a of the resin liquid supply nozzle 741 to the central region of the surface 10a (processed surface) of the semiconductor wafer 10 as shown in FIG. For about 30 seconds. The liquid resin 100 is preferably a water-soluble resist such as PVA (Poly Vinyl Alcohol), PEG (Poly Ethylene Glycol), or PEO (Poly Ethylene Oxide). As a result, the liquid resin 100 dropped on the central region of the surface 10a (processed surface) of the semiconductor wafer 10 flows to the outer peripheral portion by centrifugal force and covers the surface 10a of the semiconductor wafer 10. This liquid resin is cured with time to form a protective film 110 on the surface 10a of the semiconductor wafer 10 as shown in FIG. 10 (protective film coating step). The thickness of the protective coating 110 is determined by the amount of the liquid resin 100 dripped from the resin liquid supply nozzle 741, but may be about 1 to 10 μm.

  If the protective film 110 is coated on the surface 10a which is the processing surface of the semiconductor wafer 10 by the protective film coating process described above, the spinner table 711 is positioned at the workpiece loading / unloading position shown in FIG. The suction holding of the held semiconductor wafer 10 is released. Then, the semiconductor wafer 10 on the spinner table 711 is sucked and held by the holding means 171 of the second transfer means 17 and is transferred onto the suction chuck 32 of the chuck table 3 by a turning operation around the support means 172. The suction chuck 32 holds the suction. The chuck table 3 that sucks and holds the semiconductor wafer 10 in this way is positioned directly below the imaging means 5 disposed in the laser beam irradiation means 4 by a moving 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. The alignment of the laser beam irradiation position is similarly performed on the street 101 formed on the semiconductor wafer 10 and extending at right angles to the predetermined direction. At this time, the protective film 110 is formed on the surface 10a of the semiconductor wafer 10 on which the street 101 is formed. However, if the protective film 110 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. 11A, the semiconductor wafer 10 is positioned so that one end of the street 101 (the left end in FIG. 11A) is located directly below the condenser 42. Next, the chuck table 3, that is, the semiconductor wafer 10 is moved at a predetermined processing feed speed in the direction indicated by the arrow X 1 in FIG. 11A while irradiating a pulse laser beam from the condenser 42 of the laser beam irradiation means 4 (laser beam). Irradiation step). Then, as shown in FIG. 11B, when the other end of the street 101 (the right end in FIG. 11B) 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 beam irradiation 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 beam irradiation process described above, a laser processing groove 120 is formed on the street 101 of the semiconductor wafer 10 as shown in FIG. At this time, even if the debris 130 is generated by the irradiation of the laser beam as shown in FIG. 12, the debris 130 is blocked by the protective film 110 and does not adhere to the device 102 and the bonding pad. Then, the laser beam irradiation process described above is performed on all the streets 101 of the semiconductor wafer 10.

In addition, the said laser beam irradiation process is performed on the following process conditions, for example.
Laser light source: YVO4 laser or YAG laser Wavelength: 355 nm
Repetition frequency: 20 kHz
Output: 3W
Pulse width: 0.1 ns
Condensing spot diameter: φ5μm
Processing feed rate: 100 mm / sec

  If the laser beam irradiation process described above is performed along all the streets 101 of the semiconductor wafer 10, the chuck table 3 holding the semiconductor wafer 10 is first returned to the position where the semiconductor wafer 10 is sucked and held. The suction holding of the semiconductor wafer 10 is released. Then, the semiconductor wafer 10 is sucked and held by the holding means 171 of the second transfer means 17 and is transferred onto the suction chuck 811a of the spinner table 811 constituting the cleaning means 8 by a swiveling operation around the support means 172. It is sucked and held by the suction chuck 811a. At this time, the washing water nozzle 841 and the air nozzle 851 are positioned at a standby position separated from the upper side of the spinner table 811 as shown in FIGS.

  If the processed semiconductor wafer 10 is held on the spinner table 811 of the cleaning means 8, a cleaning process is executed. That is, the spinner table 811 is positioned at the work position shown in FIG. 7 and the electric motor 842 of the cleaning water supply means 86 is driven to hold the nozzle outlet 841a of the cleaning water supply nozzle 841 on the spinner table 811. It is positioned above the center of the semiconductor wafer 10. Then, while rotating the spinner table 811 at a rotational speed of, for example, 300 to 500 rpm, cleaning water composed of pure water and air is ejected from the ejection port of the nozzle portion 841a. That is, the nozzle portion 841a is constituted by a so-called two-fluid nozzle and is supplied with pure water of about 0.2 MPa, and is supplied with air of about 0.3 to 0.5 MPa, and the pure water is ejected by air pressure. The surface 10a that is the processed surface of the semiconductor wafer 10 is cleaned. At this time, from the position where the electric motor 842 is driven and the cleaning water ejected from the nozzle 841a of the cleaning water supply nozzle 841 hits the center of the semiconductor wafer 10 held by the spinner table 811 to the position hitting the outer periphery. It can be swung within the required angle range. As a result, since the protective film 110 coated on the surface 10a of the semiconductor wafer 10 is formed of the water-soluble resin as described above, the protective film 110 can be easily washed away and debris generated during laser processing can be removed. 130 is also removed.

  When the above-described cleaning process is completed, a drying process is performed. That is, the cleaning water supply nozzle 841 is positioned at the standby position, and the ejection port of the nozzle portion 851a constituting the air nozzle 851 of the air supply means 85 is positioned above the central portion of the semiconductor wafer 10 held on the spinner table 811. Then, while rotating the spinner table 711 at a rotational speed of 2000 to 3000 rpm, for example, air is ejected from the ejection port of the nozzle portion 851a for about 15 seconds. At this time, the air nozzle 851 is swung in a required angle range from a position where the air ejected from the nozzle portion 851 a hits the center of the semiconductor wafer 10 held by the spinner table 811 to a position where it hits the outer peripheral portion. As a result, the surface of the semiconductor wafer 10 is dried.

  As described above, when cleaning and drying of the processed semiconductor wafer 10 are completed, the rotation of the spinner table 811 is stopped and the air nozzle 851 of the air supply means 85 is positioned at the standby position. Then, the spinner table 811 is positioned at the workpiece loading / unloading position shown in FIG. 6 and the suction and holding of the semiconductor wafer 10 held by the spinner table 811 is released. Next, the processed semiconductor wafer 10 on the spinner table 811 is carried out to the temporary placement table 15 disposed in the temporary placement portion 15 a by the first transport means 16. The processed semiconductor wafer 10 carried out to the temporary placement table 15 is stored in a predetermined position of the cassette 13 by the workpiece carrying-out means 14.

  It is to be noted that while the semiconductor wafer 10 subjected to the laser beam irradiation process described above is transported to the cleaning means 8 and the cleaning process and the drying process are being performed, the workpiece carrying-in / out means 14 is operated to perform the next processing. The previous semiconductor wafer 10 is carried out from the cassette 13 to the temporary placing table 15, and the semiconductor wafer 10 carried out to the temporary placing table 15 is carried to the protective film forming means 7 by the first carrying means 16. Then, the above-described protective film coating step is performed on the semiconductor wafer 10 to be processed next, which is conveyed to the protective film forming means 7. The semiconductor wafer 10 thus subjected to the protective film coating process is conveyed from the protective film forming means 7 to the chuck table 3 by the second conveying means 17 and the laser beam irradiation process described above is performed. Then, the semiconductor wafer 10 subjected to the laser beam irradiation process is transported to the cleaning means 8 by the second transport means 17, and the above-described cleaning process and drying process are performed. Thus, in the illustrated embodiment, since the protective film forming means 7 and the cleaning means 8 are provided, the cleaning process and the drying process are performed on the semiconductor wafer 10 on which the laser beam irradiation process has been performed. In addition, since the semiconductor wafer 10 to be processed next can be conveyed to the protective film forming means 7 and the protective film coating step can be performed, the production efficiency can be improved.

The perspective view of the laser processing apparatus comprised according to this invention. The perspective view which fractures | ruptures and shows a part of protective film formation means with which the laser processing apparatus shown in FIG. 1 is equipped. Explanatory drawing which shows the state which located the spinner table of the protective film formation means shown in FIG. 2 in the workpiece carrying in / out position. Explanatory drawing which shows the state which located the spinner table of the protective film formation cleaning means shown in FIG. 2 in the working position. The perspective view which fractures | ruptures and shows a part of washing | cleaning means with which the laser processing apparatus shown in FIG. 1 is equipped. Explanatory drawing which shows the state which located the spinner table of the washing | cleaning means shown in FIG. 2 in the workpiece carrying in / out position. Explanatory drawing which shows the state which located the spinner table of the washing | cleaning means shown in FIG. 2 in the working position. The perspective view of the semiconductor wafer as a to-be-processed object processed with the laser processing apparatus shown in FIG. Explanatory drawing which shows the protective film coating process implemented by the laser processing apparatus shown in FIG. The principal part expanded sectional view of the semiconductor wafer as a workpiece by which the protective film was coat | covered by the protective film formation process. Explanatory drawing which shows the laser beam irradiation process by the laser processing apparatus shown in FIG. The principal part expanded sectional view of the semiconductor wafer as a to-be-processed object laser-processed by the laser beam irradiation process shown in FIG.

Explanation of symbols

2: Device housing 3: Chuck table 4: Laser beam irradiation means 41: Laser beam oscillation means 42: Condenser 5: Imaging mechanism 6: Display means 7: Protective film forming means 71: Spinner table mechanism 711: Spinner table 712: Electric motor 72: Washing water receiving means 74: Resin liquid supply means 741: Resin liquid supply nozzle 8: Cleaning means 81: Spinner table mechanism 811: Spinner table 812: Electric motor 82: Washing water receiving means 78: Washing water supply means 841: Washing Water nozzle 85: Air supply means 851: Air nozzle 10: Semiconductor wafer 101: Street 102: Device 110: Protective coating 11: Ring frame 12: Protective tape 13: Cassette 14: Workpiece carrying / carrying means 15: Temporary placement Table 16: First carrying It means 17: the second transport means

Claims (2)

A chuck table for holding a workpiece, a laser beam irradiation means for irradiating the workpiece held on the chuck table with a laser beam, a cassette mounting table on which a cassette containing the workpiece is placed, and the cassette Loading / unloading means for unloading and loading a workpiece from a cassette placed on the loading table, a temporary placing table for temporarily placing the workpiece unloaded by the loading / unloading means, the temporary placing table, and the chuck In a laser processing apparatus comprising a conveying means for conveying a workpiece between tables,
Protective film forming means that is disposed in the first transport path for transporting the workpiece before being unloaded to the temporary table to the chuck table, and that covers the processed surface of the workpiece before machining. When,
The protective film coated on the processed surface of the processed workpiece is removed by washing in the second transfer path for transferring the processed workpiece held on the chuck table to the temporary table. Cleaning means,
Laser processing equipment characterized by that.   The conveying means conveys the workpiece to be processed, which has been unloaded to the temporary table, to the protective film forming means, and conveys the workpiece to be processed, which has been cleaned by the cleaning means, to the temporary table. The first transporting means and the unprocessed workpiece coated with the protective coating by the protective coating forming means are transported to the chuck table and the processed workpiece held on the chuck table is cleaned with the cleaning means. The laser processing apparatus according to claim 1, further comprising: a second transport unit that transports to the surface.

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