JP2014175610A - Annular frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an annular frame in which liquid resin does not remain.SOLUTION: In an annular frame having an opening for housing a wafer, and being used when forming a protective film by sticking the outer peripheral part of a dicing tape and sticking a wafer to the dicing tape while positioning at the opening, and then coating the working surface of the wafer with liquid resin, the upper surface, the outer peripheral surface and the lower surface are subjected to water repellent treatment.

Description

  The present invention relates to an annular frame used when laser processing is performed on a 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 (streets) is divided into individual devices by a processing apparatus. Widely used in various electric devices such as mobile phones and 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 by rotating a cutting blade having a thickness of about 30 μm by solidifying diamond or other abrasive grains with a metal or resin at a high speed of about 30000 rpm. And split.

  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 is absorptive to the wafer, and an external force is applied to the wafer by a breaking device to perform the wafer along the laser processing groove. Has been proposed (see, for example, Japanese Patent Laid-Open No. 10-305420).

  Laser processing grooves formed by a laser processing apparatus can increase the processing speed compared to a dicing method using a dicer, and relatively easily process 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, in Japanese Patent Application Laid-Open No. 2004-322168, in order to solve such a problem caused by debris, water processing such as PVA (polyvinyl alcohol) and PEG (polyethylene glycol) is applied to the processed surface of the wafer. There has been proposed a laser processing apparatus in which a protective liquid film is applied to coat a protective film and a wafer is irradiated with a pulse laser beam through the protective film.

JP-A-10-305420 JP 2004-322168 A

  However, there is a problem in that the water-soluble liquid resin remains on the upper surface and the outer peripheral side surface of the annular frame, and the remaining water-soluble liquid resin adheres to the conveyance device when the wafer is conveyed together with the annular frame, thereby hindering conveyance. is there.

  In addition, when a protective film coating apparatus is not incorporated in the laser processing apparatus, a protective film is formed on the processing surface of the wafer by an independent protective film coating apparatus, and then the wafer is accommodated in the cassette and the wafer is laser processing apparatus. However, if the wafer is transported from the cassette to the temporary placement table together with the annular frame by the transportation device of the laser processing device, there is a problem that the annular frame adheres to the transportation device or adheres to the temporary placement table, resulting in a transportation trouble. is there.

  The present invention has been made in view of these points, and an object thereof is to provide an annular frame in which no liquid resin remains on the frame.

  According to the present invention, the wafer has an opening, the outer periphery of the dicing tape is attached, the wafer is positioned in the opening and attached to the dicing tape, and a liquid resin is applied to the processed surface of the wafer. An annular frame is provided for use in forming a protective film by coating, wherein an upper surface, an outer peripheral surface, and a lower surface are subjected to water repellent treatment.

  In the annular frame of the present invention, the upper surface, outer peripheral surface and lower surface are subjected to water repellency treatment, so even if the liquid resin adheres to the frame when the liquid resin is applied to the processed surface of the wafer, the liquid resin The frame is not bounced and remains due to the water repellency of the frame, and the frame adheres to the conveyance device when the wafer is conveyed together with the frame, or the frame adheres to the unloading device that unloads the wafer with frame from the cassette. It is possible to eliminate the problem of causing troubles in transportation due to adhesion to the table.

It is an external appearance perspective view of a laser processing apparatus. It is a perspective view of 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 protective film coating apparatus. It is a side view of an annular frame pressing means. It is a longitudinal cross-sectional view of the protective film coating apparatus in a state where the spinner table is raised. It is a longitudinal cross-sectional view of the protective film coating apparatus in a state where the spinner table is lowered and a water repellent treatment is applied to the annular frame. FIG. 3 is a longitudinal sectional view of a protective film coating apparatus in a state where a liquid film is discharged on a circular frame and then a liquid resin is discharged to spin coat the liquid resin on the entire surface of the wafer to form a protective film. It is a perspective view in the state where water repellent treatment is performed to the annular frame by hand.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an external appearance of a laser processing apparatus 2 that includes a protective film coating apparatus of the present invention that can perform water-repellent treatment on an annular frame and that can perform laser processing on a wafer.

  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 orthogonally, 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 is provided a loading / unloading means 10 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 protective film coating apparatus. The protective film coating apparatus 30 also serves as a cleaning apparatus 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 region 12 is adsorbed by the transport means 16 and transported to the protective film coating apparatus 30. In the protective film coating apparatus 30, a protective film is coated on the processed surface of the wafer W as 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 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 28 that condenses the laser beam on the wafer to be processed at the tip of the casing 26. Is installed.

  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 pulse width setting unit 40, and a wavelength setting unit 42.

  The repetition frequency setting means 38, the pulse width setting means 40, and the wavelength setting means 42 constituting the laser beam modulating means 36 are of a well-known form and will not be described in detail in this specification.

  The wafer W which has been subjected to laser processing by the laser beam irradiation unit 24 is held by the conveying means 32 which is movable in the Y-axis direction after moving the chuck table 18 in the X-axis direction, and is covered with a protective film that also serves as a cleaning device It is conveyed to the device 30. The protective film coating apparatus 30 cleans the wafer by rotating the wafer W at a low speed (for example, 800 to 1000 rpm) while spraying water from the cleaning nozzle.

  After cleaning, the wafer W is dried by rotating the wafer W at high speed (for example, 1500 to 2000 rpm) 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 further carried out. The wafer W is returned to the original storage location of the wafer cassette 8 by the insertion means 10.

  Next, the protective film coating apparatus 30 according to the embodiment of the present invention will be described in detail with reference to FIGS. 4 to 8. First, referring to FIG. 4, a partially broken perspective view of the protective film coating apparatus 30 is shown.

  The protective film coating apparatus 30 includes a spinner table mechanism 44 and a cleaning water receiving mechanism 46 that surrounds the spinner table mechanism 44. The spinner table mechanism 44 includes a spinner 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 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 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 move the electric motor 50 and the spinner table 48 at the wafer loading / unloading position, which is the rising position shown in FIG. 6, and the lowered position, shown in FIG. It can be positioned at a certain work position.

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

  As shown in FIG. 6, the washing water 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 peripheral edge thereof.

  When the electric motor 50 and the spinner table 48 are positioned at the work position shown in FIG. 7, the cover member 62 configured as described above has a gap on the outside of the inner wall 58 c constituting the cleaning water receiving container 58. It is positioned to polymerize.

  The protective film coating apparatus 30 includes an application unit 66 that applies a liquid resin to an unprocessed semiconductor wafer held by a spinner table 48. The application unit 66 includes a discharge nozzle 68 that discharges the liquid resin toward the processed surface of the wafer before processing held by the spinner table 48, and an approximately L-shaped arm 70 that supports the discharge nozzle 68.

  The coating means 66 further includes a liquid resin discharge position corresponding to the central portion of the wafer W supported by the spinner table 48 with the discharge nozzle 68 supported by the arm 70, and a retracted position shown in FIG. And an electric motor 72 capable of normal / reverse rotation that swings between the two. The discharge nozzle 68 is connected to a liquid resin supply source (not shown) via an arm 70.

  The protective film coating apparatus 30 includes water repellent treatment means 74 that performs water repellent treatment on the annular frame F. The water repellent treatment means 74 includes a nozzle 78 that performs water repellent treatment on the upper surface and side surfaces of the annular frame F held by the spinner table 48 and a nozzle 80 that performs water repellent treatment on the lower surface of the annular frame F. The nozzle 78 is attached by a motor 82 so as to be swingable between the working position and the retracted position shown in FIG.

  The protective film coating apparatus 30 also serves as a cleaning apparatus for cleaning the wafer after laser processing. Therefore, the protective film coating apparatus 30 includes cleaning water supply means 76 for cleaning the processed wafer held by the spinner table 48.

  The cleaning water supply means 76 includes a cleaning water nozzle 84 that ejects cleaning water toward the processed wafer held by the spinner table 48, an arm 86 that supports the cleaning water nozzle 84, and a cleaning supported by the arm 86. It comprises a motor (not shown) that swings the water nozzle 84. The cleaning water nozzle 84 is connected to a cleaning water supply source (not shown) via an arm 86.

  The spinner table 48 is provided with four pendulum type annular frame pressing means 49 for pressing the annular frame F. The annular frame pressing means 49 includes a support portion 88 fixed to the spinner table 48 and a pendulum body (clamp) 90 that is rotatably attached to the support portion 88. The pendulum body 90 is rotatably attached to the support portion 88 via a pendulum shaft 95. A snap ring 98 prevents the pendulum shaft 98 from coming off.

  The pendulum body 90 is made of, for example, a ferromagnetic material such as iron, and includes a weight portion 92 and a claw portion 94 that presses an annular frame F formed integrally with the weight portion 92. A weight fixing portion 96 made of a permanent magnet is attached to the support portion 88.

  When the rotation speed of the spinner table 48 is equal to or lower than a predetermined speed, the pendulum body 90 is fixed by the magnetic force of the weight fixing portion 96 overcoming the centrifugal force of the pendulum body 90 and the weight portion 92 is attracted to the weight fixing portion 96 and fixed. The portion 94 is positioned at the release position shown in FIG. 5, and when the rotation speed of the spinner table 48 is higher than a predetermined speed, the centrifugal force of the pendulum body 90 overcomes the magnetic force of the weight fixing portion 96 and the weight portion 90 becomes the weight fixing portion 96. The magnetic force of the weight fixing portion 96, the type of the ferromagnetic material of the pendulum body 90, and the mass thereof are set so that the claw portion 94 is positioned at a pressing position where the claw portion 94 presses the annular frame F.

  The pendulum body 90 does not need to be entirely formed of a ferromagnetic material, and a part of the weight portion 92 that is attracted by the magnetic force of the weight fixing portion 96 may be formed of a ferromagnetic material. In the present embodiment, the predetermined speed is set to 1000 rpm.

  Hereinafter, the operation of the protective film coating apparatus 30 configured as described above will be described. The semiconductor wafer W before processing is transported to the spinner table 48 of the protective film coating apparatus 30 by the turning operation of the wafer transport means 16, and is sucked and held by the suction chuck 48a.

  At this time, the spinner table 48 is positioned at the wafer loading / unloading position shown in FIG. 6, and the discharge nozzle 68, the nozzle 78, and the cleaning nozzle 84 are retracted from above the spinner table 48 as shown in FIG. Is positioned.

  If the unprocessed wafer W is held on the spinner table 48 of the protective film coating apparatus 30, a water repellent treatment process for subjecting the annular frame F to a water repellent treatment is performed. In order to perform the water repellent process, the air cylinder 56 is driven and the spinner table 48 is moved in the direction of arrow A in FIG.

  Further, the nozzle 78 of the water repellent treatment means 74 is rotated by the motor 82 and positioned above the annular frame F. The motor 50 is driven while the water repellent is ejected from the nozzles 78 and 80, and the spinner table 48 is rotated at a low speed of about 100 rpm in the direction of the arrow R1, and water repellent treatment is performed on the upper surface, outer peripheral surface and lower surface of the annular frame F. Apply. At this time, the weight portion 92 of the pendulum body 90 is fixed to the weight fixing portion 96 by magnetic force.

  Here, as the water repellent treatment of the annular frame F, a coating of (ReviveX wash-in water repellent) provided by McNTT of the United States can be employed.

  After the water repellent treatment of the annular frame F, a protective film coating step is performed. In the protective film coating step, the motor 72 is driven to position the discharge nozzle 68 of the coating means 66 at the work position shown in FIG. 8 and the liquid resin 69 is discharged onto the wafer W, and then the electric motor 50 is driven. Then, the spinner table 48 is rotated in the direction of the arrow R1 at about 200 rpm, and the discharged liquid resin is spin-coated on the entire surface of the wafer W.

  Since the spinner table 48 is rotated at a relatively low speed of 200 rpm, the weight portion 92 of the pendulum body 90 is fixed to the weight fixing portion 96 by a magnetic force. Since the spinner table 48 is rotated at a rotation speed of 200 rpm, it is possible to form a protective film by uniformly spin-coating the liquid resin on the surface of the wafer W.

  The liquid resin for forming the protective film is preferably a water-soluble resist such as PVA (polyvinyl alcohol), PEG (polyethylene glycol), PEO (polyethylene oxide).

  According to the protective film coating apparatus 30 described above, the water repellent treatment is applied to the upper surface, the outer peripheral surface and the lower surface of the annular frame F before the protective film is coated, so that the liquid resin is applied to the processed surface of the wafer W. Even if the liquid resin adheres to the annular frame F, the annular frame F is water-repellent, so that the liquid resin is not repelled and remains by the water repellency of the annular frame F. The annular frame F does not adhere to the conveying means 16 when conveying the wafer W.

  In the above-described embodiment, the example in which the protective film coating apparatus 30 is provided with the water-repellent treatment means 74 has been described. However, the water-repellent treatment of the annular frame F is performed manually by a spray can 90 as shown in FIG. You may make it do.

  That is, the operator may grasp the spray can 90 and apply glass coating or fluorine coating such as Teflon (registered trademark) on the annular frame F so that the annular frame F has water repellency. Alternatively, a glass coating or a fluorine coating such as Teflon may be applied without using the spray can 90.

W Semiconductor wafer F Circular frame T Dicing tape 2 Laser processing device 18 Chuck table 24 Laser beam irradiation unit 28 Condenser 30 Protective film coating device 48 Spinner table 66 Liquid resin coating means 68 Discharge nozzle 74 Water repellent coating means 78, 80 nozzle 90 spray can

Claims (1)

It has an opening for accommodating the wafer, and the outer peripheral portion of the dicing tape is attached to the wafer, and the wafer is positioned at the opening and attached to the dicing tape, and a liquid resin is applied to the processed surface of the wafer to provide a protective film. An annular frame used when forming
An annular frame characterized in that water repellent treatment is applied to the upper surface, outer peripheral surface and lower surface.

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