JP2011156480A - Liquid resin coating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid resin coating device which enables economical coating of a liquid resin. <P>SOLUTION: The liquid resin coating device for applying a liquid resin to a plate-like material includes a liquid resin supply means having a support table for rotatably supporting the plate-like material, a liquid resin supply nozzle for supplying the liquid resin to the exposed surface of the plate-like material supported by the support table and a liquid resin supply source communicating with the liquid resin supply nozzle, a liquid receiving container having a liquid discharge port in the bottom arranged so as to surround the support table, and a recovery passage for recovering the liquid resin accumulated in the liquid receiving container from the liquid discharge port. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid resin coating apparatus for coating a liquid resin on a plate-like material such as a semiconductor wafer.

  A wafer such as a silicon wafer or a sapphire wafer formed on the surface by dividing a plurality of devices such as IC, LSI, LED, etc. by dividing lines is divided into individual devices by a processing apparatus, and the divided devices are mobile phones, Widely used in various electronic devices such as personal computers.

  A dicing method using a cutting device called a dicer is widely used for dividing the wafer. In the dicing method, a wafer is cut by cutting a wafer into a wafer while rotating a cutting blade having a thickness of about 30 μm by solidifying abrasive grains such as diamond with a metal or a resin at a high speed of about 30000 rpm. Divide into

  On the other hand, in recent years, a laser processing groove is formed by irradiating a wafer with a pulsed laser beam having a wavelength that absorbs the wafer, and the wafer is cut along the laser processing groove by a breaking device. A method of dividing into devices has been proposed (see, for example, Japanese Patent Laid-Open No. 10-305420).

  The formation of the laser processing groove by the laser processing apparatus can increase the processing speed as compared with the dicing method using the dicer, and relatively easily processes even a wafer made of a material having high hardness such as sapphire or SiC. be able to. In addition, since the processing groove can be made to have a narrow width of, for example, 10 μm or less, the amount of devices taken per wafer can be increased as compared with the case of processing by the dicing method.

  However, when the wafer is irradiated with a pulse laser beam, debris is generated due to concentration of thermal energy in the region irradiated with the pulse laser beam. When this debris adheres to the device surface, there arises a problem that the quality of the device is lowered.

  Therefore, for example, Japanese Patent Application Laid-Open No. 2004-322168 or Japanese Patent Application Laid-Open No. 2007-201178 discloses a PVA (polyvinyl alcohol), PEG (polyethylene glycol) or the like on the processed surface of the wafer in order to solve such a problem caused by debris. There has been proposed a laser processing apparatus in which a water-soluble resin is applied to cover a protective film and a wafer is irradiated with a pulsed laser beam through the protective film.

JP-A-10-305420 JP 2004-322168 A JP 2007-2011178 A

  However, in the apparatus disclosed in Patent Document 2, after the liquid resin is supplied to the processing surface of the wafer held by the spinner table, it is moved to the outer periphery of the wafer by the centrifugal force accompanying the rotation of the spinner table. A protective film is formed on the processed surface of the wafer using a so-called spin coating method in which a liquid resin is applied to the entire processed surface.

  However, the formation of the protective film by such a spin coating method has a problem that it is very uneconomical because 90% or more of the supplied liquid resin is scattered and discarded.

  This invention is made | formed in view of such a point, The place made into the objective is providing the liquid resin coating device which enables application | coating of liquid resin economically.

  According to the present invention, there is provided a liquid resin coating apparatus for applying a liquid resin to a plate-like material, the holding table rotatably holding the plate-like material, and a liquid on the exposed surface of the plate-like material held by the holding table. A liquid resin supply means having a liquid resin supply nozzle for supplying resin, a liquid resin supply source communicating with the liquid resin supply nozzle, and a drain port at a bottom portion surrounding the holding table. There is provided a liquid resin coating apparatus comprising: a liquid receiving container; and a recovery path for recovering the liquid resin accumulated in the liquid receiving container from the drain port to the liquid resin supply source.

  Preferably, the liquid resin coating device includes a cleaning liquid nozzle that supplies a cleaning liquid to the exposed surface of the plate-like object held by the holding table, and a cleaning liquid supply unit that communicates with the cleaning liquid nozzle, A drainage path for draining the drainage from the drainage port, and switching means for selectively communicating the drainage port with the recovery path or the drainage path are further provided.

  In the liquid resin coating apparatus of the present invention, since the liquid resin scattered by spin coating is recovered to the liquid resin supply source via the recovery path, the liquid resin can be reused and is very economical.

  Further, in the configuration provided with the cleaning liquid supply means and the switching means, the waste liquid generated when the plate-like object is cleaned can be discarded and only the liquid resin scattered during the liquid resin application can be reused. By incorporating it into a processing device, its utility value increases.

It is an external appearance perspective view of a laser processing apparatus. It is a perspective view which shows the wafer supported by the annular frame via the dicing tape. It is a block diagram of a laser beam irradiation unit. It is a partially broken perspective view of a liquid resin coating device. It is a longitudinal cross-sectional view of the liquid resin coating device in a state where the spinner table is raised and the wafer is held on the spinner table.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown a perspective view of a laser processing apparatus 2 that includes the liquid resin coating apparatus of the present invention and can divide a wafer into individual chips (devices) by laser processing.

  On the front side of the laser processing apparatus 2, operation means 4 is provided for an operator to input instructions to the apparatus such as processing conditions. In the upper part of the apparatus, there is provided a display means 6 such as a CRT for displaying a guidance screen for an operator and an image taken by an imaging means described later.

  As shown in FIG. 2, on the surface of the semiconductor wafer W to be processed, the first street S1 and the second street S2 are formed to be orthogonal to each other, and the first street S1 and the second street S2 are formed. A number of devices D are formed in a region partitioned by.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer peripheral edge of the dicing tape T is attached to an annular frame F. As a result, the wafer W is supported by the annular frame F via the dicing tape T, and a plurality of wafers (for example, 25 sheets) are accommodated in the wafer cassette 8 shown in FIG. The wafer cassette 8 is placed on a cassette elevator 9 that can move up and down.

  Behind the wafer cassette 8, loading / unloading means 10 is provided for unloading the wafer W before laser processing from the wafer cassette 8 and loading the processed wafer into the wafer cassette 8.

  Between the wafer cassette 8 and the loading / unloading means 10, a temporary placement area 12, which is an area on which a wafer to be loaded / unloaded is temporarily placed, is provided. A wafer W is fixed in the temporary placement area 12. Positioning means 14 for positioning to the position of is arranged.

  Reference numeral 30 denotes a liquid resin coating device. The liquid resin coating device 30 also serves as a cleaning device for cleaning the processed wafer. In the vicinity of the temporary placement region 12, a transport unit 16 having a turning arm that sucks and transports the frame F integrated with the wafer W is disposed.

  The wafer W carried out to the temporary placement area 12 is adsorbed by the conveying means 16 and conveyed to the liquid resin coating device 30. The liquid resin coating apparatus 30 coats a protective film by applying a liquid resin to the processed surface of the wafer W as will be described in detail later.

  The wafer W whose processing surface is coated with a protective film is attracted by the conveying means 16 and conveyed onto the chuck table 18 and is sucked by the chuck table 18, and the frame F is fixed by a plurality of fixing means (clamps) 19. As a result, the chuck table 18 is held.

  The chuck table 18 is configured to be rotatable and reciprocally movable in the X-axis direction. Above the movement path of the chuck table 18 in the X-axis direction, an alignment unit 20 that detects a street of the wafer W to be laser processed. Is arranged.

  The alignment unit 20 includes an imaging unit 22 that images the surface of the wafer W, and can detect a street to be laser processed by image processing such as pattern matching based on an image acquired by imaging. The image acquired by the imaging unit 22 is displayed on the display unit 6.

  A laser beam irradiation unit 24 that irradiates the wafer W held on the chuck table 18 with a laser beam is disposed on the left side of the alignment means 20. The laser beam irradiation unit 24 is movable in the Y axis direction.

  The casing 26 of the laser beam irradiation unit 24 accommodates laser beam oscillation means and the like which will be described in detail later, and a condenser (a light collector for condensing the laser beam on the wafer to be processed) at the tip of the casing 26. A laser head) 28 is attached.

  In the casing 26 of the laser beam irradiation unit 24, a laser beam oscillation means 34 and a laser beam modulation means 36 are disposed as shown in the block diagram of FIG.

  As the laser beam oscillation means 34, a YAG laser oscillator or a YVO4 laser oscillator can be used. The laser beam modulating unit 36 includes a repetition frequency setting unit 38, a laser beam pulse width setting unit 40, and a laser beam wavelength setting unit 42.

  The repetition frequency setting means 38, the laser beam pulse width setting means 40, and the laser beam wavelength setting means 42 constituting the laser beam modulation means 36 are of known forms, and detailed description thereof is omitted in this specification.

  The wafer W that has been subjected to laser processing by the laser beam irradiation unit 24 is moved by the chuck means 18 in the X-axis direction and is then held by the conveying means 32 that can move in the Y-axis direction. It is conveyed to the device 30. The liquid resin coating apparatus 30 cleans the wafer by rotating the wafer W at a low speed (for example, 300 rpm) while spraying water from the cleaning nozzle.

  After cleaning, the wafer W is dried at a high speed (for example, 2000 rpm) by blowing air from the air nozzle to dry the wafer W, and then the wafer W is adsorbed by the conveying means 16 and returned to the temporary storage area 12, and then the loading / unloading means 10, the wafer W is returned to the original storage location of the wafer cassette 8.

  Next, with reference to FIG.4 and FIG.5, the detailed structure of the liquid resin coating device 30 which concerns on this embodiment is demonstrated. First, referring to FIG. 4, a partially broken perspective view of the liquid resin coating device 30 is shown.

  The liquid resin coating device 30 includes a spinner table mechanism 44 and a liquid receiving mechanism 46 disposed so as to surround the spinner table mechanism 44. The spinner table mechanism 44 includes a spinner table (holding table) 48, an electric motor 50 that rotationally drives the spinner table 48, and a support mechanism 52 that supports the electric motor 50 so as to be movable in the vertical direction.

  The spinner table 48 includes a suction chuck (holding surface) 48a formed of a porous material, and the suction chuck 48a communicates with suction means (not shown). Accordingly, the spinner table 48 holds the wafer on the suction chuck 48a by placing the wafer on the suction chuck 48a and applying a negative pressure by suction means (not shown).

  The spinner table 48 is provided with a pair of pendulum type clamps 49. When the spinner table 48 is rotated, the clamp 49 swings by a centrifugal force to clamp the annular frame F shown in FIG.

  The spinner table 48 is connected to the output shaft 50 a of the electric motor 50. The support mechanism 52 includes a plurality of (three in the present embodiment) support legs 54 and a plurality of (three in the present embodiment) air cylinders 56 respectively connected to the support legs 54 and attached to the electric motor 50. It consists of.

  The support mechanism 52 configured as described above operates the air cylinder 56 to operate the electric motor 50 and the spinner table 48 at the wafer loading / unloading position, which is the rising position shown in FIG. Can be positioned.

  The liquid receiving mechanism 46 includes a liquid receiving container 58, three support legs 60 that support the liquid receiving container 58 (only two are shown in FIG. 4), and a cover member that is attached to the output shaft 50a of the electric motor 50. 62.

  As shown in FIG. 5, the liquid receiving container 58 includes a cylindrical outer wall 58a, a bottom wall 58b, and an inner wall 58c. A hole 51 into which the output shaft 50a of the electric motor 50 is inserted is provided at the center of the bottom wall 58b, and the inner wall 58c is formed so as to protrude upward from the periphery of the hole 51.

  As shown in FIG. 4, a waste liquid port 59 is provided on the bottom wall 58 b, and a drain hose 64 is connected to the waste liquid port 59. The cover member 62 is formed in a disc shape, and includes a cover portion 62a that protrudes downward from the outer periphery thereof.

  When the electric motor 50 and the spinner table 48 are positioned at the working position, the cover member 62 configured in this manner is overlapped so that the cover portion 62a overlaps the outside of the inner wall 58c constituting the liquid receiving container 58 with a gap. Positioned on.

  The liquid resin coating apparatus 30 includes a coating unit 66 for coating the liquid resin on the unprocessed wafer W held on the spinner table 48. The application unit 66 includes a liquid resin supply nozzle 68 that supplies a liquid resin toward the processed surface of the unprocessed wafer held by the spinner table 48, a generally L-shaped arm 70 that supports the liquid resin supply nozzle 68, An electric motor 72 capable of normal / reverse rotation that swings the liquid resin supply nozzle 68 supported by the arm 70 is configured. The liquid resin supply nozzle 68 is connected to a liquid resin supply source 90 via an arm 70.

  The liquid resin coating device 30 also serves as a cleaning device for cleaning the wafer after laser processing. Therefore, the liquid resin coating apparatus 30 includes a cleaning water supply unit 74 and an air supply unit 76 for cleaning the processed wafer held by the spinner table 48.

  The cleaning water supply means 74 includes a cleaning water nozzle 78 that ejects cleaning water toward the processed wafer held by the spinner table 48, an arm 80 that supports the cleaning water nozzle 78, and a cleaning that is supported by the arm 80. An electric motor 82 that can rotate forward and reverse is provided to swing the water nozzle 78. The cleaning water nozzle 78 is connected to the cleaning water supply source 92 via the arm 80.

  The air supply means 76 includes an air nozzle 84 that blows air toward the cleaned wafer held by the spinner table 48, an arm 86 that supports the air nozzle 84, and a positive that swings the air nozzle 84 that is supported by the arm 86. An electric motor (not shown) capable of rotating and reversing is provided. The air nozzle 84 is connected to an air supply source (not shown) via an arm 86.

  The drain hose 64 connected to the drainage port 59 is selectively connected to the recovery path 96 or the drainage path 98 by switching means 94 such as a switching valve. The recovery path 96 is connected to the liquid resin supply source 90, and the drainage path 98 is connected to the drainage tank 100.

  Next, the operation of the liquid resin coating apparatus 30 configured as described above will be described. The wafer before processing is transported to the spinner table 48 of the liquid resin coating device 30 by the turning motion of the wafer transport means 16, and is sucked and held by the suction chuck 48a as shown in FIG.

  At this time, the liquid resin supply nozzle 68, the washing water nozzle 78, and the air nozzle 84 are positioned at a standby position separated from above the spinner table 48, as shown in FIGS.

  Next, the air cylinder 56 is actuated to lower the spinner table 48, and the spinner table 48 is positioned at a working position where the cover portion 62 a overlaps the outside of the inner peripheral wall 58 c constituting the liquid receiving container 58 with a gap.

  If the spinner table 48 is positioned at the work position, the liquid resin is dropped from the liquid resin supply nozzle 68 onto the central region of the processing surface of the wafer W while the spinner table 48 is rotated at 30 to 50 rpm.

  Since the spinner table 48 is rotated, the dropped liquid resin is spin-coated on the processed surface of the wafer W, and a protective film is formed on the processed surface of the wafer W. The thickness of the protective film is preferably about 0.5 to 10 μm.

  According to this spin coating method, most of the liquid resin dropped on the central region of the processed surface of the wafer W is scattered by the rotation of the spinner table 48 and accommodated in the liquid receiving container 58.

  When the liquid resin is applied to the processed surface of the wafer W, the drain hose 64 is switched by the switching means 94 so as to be connected to the recovery path 96. Therefore, the scattered liquid resin accommodated in the liquid receiving container 58 is recovered by the liquid resin supply source 90 through the drain port 59, the drain hose 64, and the recovery path 96.

  As described above, according to the liquid resin coating apparatus 30 of the present embodiment, most of the liquid resin scattered during the spin coating is recovered to the liquid resin supply source 90 via the recovery path 96, and the liquid resin can be reused. Therefore, it is very economical.

  If the surface of the semiconductor wafer W is coated with the protective film, the spinner table 48 is positioned at the wafer loading / unloading position shown in FIG. 5 and the suction and holding of the wafer held on the spinner table 48 is released.

  The wafer W on the spinner table 48 is transported to the chuck table 18 by the wafer transport means 16 and sucked and held by the chuck table 18. Further, the chuck table 18 moves in the X-axis direction, and the wafer W is positioned immediately below the imaging means 22.

  Image processing such as pattern matching for aligning the condenser 28 and the street S of the laser beam irradiation unit 24 that irradiates the laser beam by imaging the processing area of the wafer W by the imaging means 22 is executed. The alignment of the laser beam irradiation position is performed.

  In this way, if the street S1 or S2 of the wafer W held on the chuck table 18 is detected and the alignment of the laser beam irradiation position is performed, the condenser that irradiates the chuck table 18 with the laser beam. It moves to the laser beam irradiation area | region where 28 is located, and irradiates a laser beam from the collector 28 along the street S1 or S2 of the wafer W through a protective film.

  In the laser beam irradiation step, a pulse laser beam is irradiated from the condenser 28 of the laser beam irradiation unit 24 for irradiating the laser beam toward the predetermined street S through the protective film from the surface side that is the processing surface of the wafer W The chuck table 18 is moved in the X-axis direction at a predetermined feed rate (for example, 100 mm / second).

  The laser processing conditions are as follows, for example.

Light source: YAG laser Wavelength: 355 nm (third harmonic of YAG laser)
Output: 3.0W
Repetition frequency: 20 kHz
Condensing spot diameter: 1.0 μm
Feeding speed: 100 mm / second

  By performing the laser beam irradiation process, a laser processing groove is formed along the street S on the wafer W. At this time, even if debris is generated by the laser beam irradiation, the debris is blocked by the protective film and does not adhere to the electronic circuit of the device D, the bonding pad, and the like.

  When the laser processing groove is formed on the wafer W in this way, the chuck table 18 is first returned to the position where the wafer W is sucked and held, and here, the wafer W is released from sucking and holding. Then, the wafer W is transported to the spinner table 48 of the liquid resin coating device 30 by the transport means 32, and is sucked and held by the suction chuck 48a.

  At this time, the liquid resin supply nozzle 68, the washing water nozzle 78, and the air nozzle 84 are positioned at a standby position separated from the upper side of the spinner table 48 as shown in FIGS.

  The wafer W is cleaned by rotating the wafer W at a low speed (for example, 300 rpm) while spraying cleaning water composed of pure water and air from the cleaning water supply source 92 and the cleaning water nozzle 78 connected to the air source.

  As a result, since the protective film coated on the surface of the wafer W is formed of a water-soluble resin, the protective film can be easily washed away and debris generated during laser processing is also removed.

  When cleaning the wafer W, the drain hose 64 is connected to the drainage path 98 by the switching means 94. Therefore, the drainage liquid after cleaning the wafer W is discharged to the drainage tank 100 via the drainage port 59, the drain hose 64, and the drainage path 98.

  When the cleaning process is completed, a drying process is performed. That is, the cleaning water nozzle 78 is positioned at the standby position, and the outlet of the air nozzle 84 is positioned above the outer peripheral portion of the wafer W held on the spinner table 48.

  Then, air is ejected from the air nozzle 84 toward the wafer W held on the spinner table 48 while rotating the spinner table 48 at, for example, 3000 rpm. At this time, the air ejected from the air nozzle 84 is swung within a swing range from a position where it hits the outer peripheral portion of the wafer W held by the spinner table 48 to a position where it hits the center portion. As a result, the surface of the wafer W is dried.

  After the wafer W is dried, the wafer W is adsorbed by the conveying means 16 and returned to the temporary storage area 12, and the wafer W is returned to the original storage location of the wafer cassette 8 by the carry-in / out means 10.

  The wafer W formed with the laser processing groove along the street S in this manner is then mounted on a braking device (expanding device) and the dicing tape T is expanded in the radial direction, so that the wafer W is laser processed. Divided into individual devices D along the groove.

2 Laser processing apparatus 18 Chuck table 24 Laser beam irradiation unit 28 Condenser 30 Liquid resin coating apparatus 48 Spinner table 66 Liquid resin coating means 68 Liquid resin supply nozzle 74 Cleaning means 78 Washing water nozzle 76 Drying means 84 Air nozzle

Claims (2)

A liquid resin coating apparatus for applying a liquid resin to a plate-like object,
A holding table that rotatably holds the plate-like object;
A liquid resin supply means having a liquid resin supply nozzle for supplying a liquid resin to the exposed surface of the plate-like object held by the holding table, and a liquid resin supply source communicating with the liquid resin supply nozzle;
A liquid receiving container having a drainage port at the bottom disposed surrounding the holding table;
A recovery path for recovering the liquid resin collected in the liquid receiving container from the drainage port to the liquid resin supply source;
A liquid resin coating apparatus comprising: A cleaning liquid supply means having a cleaning liquid nozzle for supplying a cleaning liquid to the exposed surface of the plate-like object held by the holding table, and a cleaning liquid supply source communicating with the cleaning liquid nozzle;
A drainage path for draining drainage from the drainage port;
The liquid resin coating apparatus according to claim 1, further comprising switching means for selectively communicating the drain port with the recovery path or the drain path.

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