JP2017216291A - Protective film formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a load of maintenance.SOLUTION: A protective film formation device (10) includes a holding table (11) that holds a wafer (W) adhered in an annular frame (F) to an upper surface through a protection tape (T). The holding table comprises: a central holding part (41) that sucks and holds a back surface of the wafer through the protection tape; and an outer periphery holding part (42) that is formed so as to surround the central holding part, and includes an outer periphery holding surface (42a) that holds the back surface of the protective tape of the outer periphery of the wafer. In the outer periphery holding surface, a communication groove (44) communicated to the central holding part is formed. When forming a protective film (Ra) to the surface of the wafer, the wafer is sucked and held to the central holding part. The back surface of the protective tape of the outer periphery of the wafer is sucked and held to the outer periphery holding part by a suction force communicated to the communication groove. Therefore, the wafer can be held without providing a clamp mechanism for clamping the annular frame.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a protective film forming apparatus for forming a protective film by applying a liquid resin to the surface of a wafer such as a semiconductor wafer or an optical device wafer.

  As a method of cleaving a wafer into individual devices, a laser processing groove is formed by irradiating the wafer with a pulsed laser beam having a wavelength that is absorptive with respect to the wafer, and the breaking machine uses the laser processing groove. A method for applying an external force to the wafer along the line has been proposed (see, for example, Patent Document 1).

  In the formation of such a laser processed groove, when a 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, in order to eliminate such problems caused by debris, a water-soluble resin such as PVA (polyvinyl alcohol) or PEG (polyethylene glycol) is applied to the processed surface of the wafer to form a protective film. There has been proposed a laser processing apparatus that irradiates a wafer with a pulsed laser beam through this protective film.

  Here, as an apparatus for forming a protective film on a wafer, for example, an apparatus disclosed in Patent Document 2 has been proposed. In Patent Document 2, a wafer attached to an annular frame via an adhesive tape is placed on a spinner table, and the annular frame is held by a pendulum clamp provided on the outer periphery of the spinner table. In this state, the protective film is applied to the wafer with a uniform thickness by supplying the liquid resin from above the wafer while rotating the wafer on the spinner table.

JP-A-10-305420 JP 2012-200673 A

  However, when the liquid resin is applied as in Patent Document 2, the liquid resin adheres to the pendulum clamp, and there is a problem that a burden is imposed on maintenance such as cleaning the pendulum clamp after that.

  The present invention has been made in view of this point, and an object thereof is to provide a protective film forming apparatus capable of reducing the maintenance burden.

  The protective film forming apparatus of the present invention supplies a liquid resin to a holding table that holds a plate-like object adhered in an annular frame on the upper surface via a protective tape, and a surface of the plate-like object held on the holding table. A liquid supply means having a liquid resin supply nozzle that rotates, and a rotation driving unit that rotates the vertical direction with respect to the upper surface of the holding table as a rotation axis, and spreads the liquid resin supplied to the plate-like object surface over the entire plate-like object surface; , And a protective film forming apparatus for forming a protective film made of a liquid resin on the surface of the plate-like object, wherein the holding table is a porous member having a holding surface for sucking and holding the back surface of the plate-like object through a protective tape. An outer periphery holding portion, and an outer periphery holding portion having an outer periphery holding surface that surrounds the plate-like object holding portion and holds at least the back surface of the protective tape on the outer periphery of the plate-like object. The outer peripheral holding surface of A communicating groove communicating with the porous member of the shaped object holding portion is formed so that the suction force from the porous member communicates with the communicating groove, and the plate shaped object is sucked and held by the plate shaped object holding portion and sucked to communicate with the communicating groove. At least the back surface of the protective tape on the outer periphery of the plate-like object is sucked and held by the outer peripheral holding portion by force, and the holding table is rotated to form a protective film on the surface of the plate-like object.

  According to this configuration, the protective tape inside the annular frame can be stably sucked and held by the communication groove formed in the outer periphery holding portion. This makes it possible to hold a plate-like object stably even if the conventional structure such as a pendulum clamp is omitted, and reduces the maintenance work load by eliminating the structure (for example, clamp) that is washed after the liquid resin adheres. can do.

  According to the present invention, it is possible to reduce the burden of maintenance such as cleaning the attached liquid resin.

It is a perspective view of the protective film formation apparatus which concerns on this Embodiment. It is a longitudinal cross-sectional view of the protective film formation apparatus which concerns on this Embodiment. It is a perspective view of the holding table concerning this embodiment.

  Hereinafter, a protective film forming apparatus according to the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a protective film forming apparatus according to the present embodiment. First, a wafer on which a protective film is formed will be described with reference to FIG.

  As shown in FIG. 1, the wafer W in the present embodiment is a disk-shaped semiconductor wafer. A protective tape T is adhered to the back surface of the wafer W, and the workpiece W is supported on the annular frame F via the protective tape T. Accordingly, the surface of the wafer W is exposed upward in the state of being stuck in the annular frame F, and a protective film Ra (see FIG. 2) described later is formed on the surface. The surface of the workpiece W is partitioned into a plurality of regions by division lines W1 arranged in a grid, and a plurality of rectangular device regions W2 are formed by the partitions. In this embodiment, a protective film is formed on a wafer W made of a semiconductor wafer as a plate-like material. However, the plate-like material is not limited to a semiconductor wafer, and may be, for example, an optical device wafer, a sapphire substrate, glass, or the like. .

  Subsequently, the protective film forming apparatus according to the present embodiment will be described. The protective film forming apparatus is not limited to the configuration shown below, and may be configured in any way as long as the protective film can be formed by supplying the liquid resin while rotating the holding table.

  The protective film forming apparatus 10 supplies the liquid resin R (see FIG. 2) to the wafer W held on the upper surface of the holding table (spinner table) 11, and the centrifugal force generated by the rotation of the holding table 11 causes the wafer W to move. The liquid resin R is applied to the entire surface. The protective film forming apparatus 10 includes a bottomed cylindrical casing 12 including a cylindrical peripheral wall portion 12a and a bottom wall portion 12b. A drain hose 14 for discharging the drained liquid in the casing 12 is connected to the bottom wall portion 12b. The casing 12 is supported on the installation surface by a plurality of legs 15 extending from the lower surface of the bottom wall portion 12b. A holding table 11 is accommodated in the casing 12, and a detailed configuration of the holding table 11 will be described later.

  At the center of the lower surface of the holding table 11, the upper end portion of the rotation shaft 21 of the electric motor (rotation drive unit) 20 is fixed. The rotary shaft 21 extends upward from the electric motor 20 located below the casing 16 and is connected to the holding table 11 through a central opening formed through the bottom wall portion 12b. A cover member 22 is attached to the rotary shaft 21 so as to close the central opening of the bottom wall portion 12b.

  A plurality (three in this embodiment) of air cylinders 24 are attached to the outer peripheral surface of the electric motor 20. The electric motor 20 is supported by a piston rod 25 abutted against the installation surface from each air cylinder 24, and is driven up and down by the expansion and contraction of the piston rod 25. The holding table 11 is rotated at a high speed in the casing 12 by the electric motor 20 and is driven up and down between a lowered position where a process of taking the wafer W is performed by a plurality of air cylinders 24.

  The protective film forming apparatus 10 includes a liquid supply unit 30, and the liquid supply unit 30 includes a liquid resin supply nozzle 31 provided inside the casing 12 and around the holding table 11. The liquid resin supply nozzle 31 is connected to the liquid resin supply source 32 and supplies the liquid resin R (see FIG. 2) to the surface of the wafer W held on the holding table 11. Here, as the liquid resin R, for example, a water-soluble resin such as polyvinyl alcohol (PVA) or polyethylene glycol (PEG) is used.

  FIG. 2 is a longitudinal sectional view of the protective film forming apparatus according to the present embodiment. As shown in FIG. 2, the liquid resin supply nozzle 31 is substantially L-shaped with a horizontal portion 31a extending horizontally above the holding table 11 and a vertical portion 31b extending downward from the base end of the horizontal portion 31a. Is formed. A dropping portion 31c directed downward is formed at the tip of the horizontal portion 31a, and the liquid resin R is dropped onto the wafer W on the holding table 11 from the dropping portion 31c. The liquid resin supply nozzle 31 is supported by the casing 12 so as to be rotatable above the holding table 11.

  Returning to FIG. 1, the protective film forming apparatus 10 not only forms a protective film on the wafer W before processing, but also functions as a cleaning apparatus that removes the protective film from the processed wafer W. In the casing 12, similarly to the liquid resin supply nozzle 31, a washing water nozzle 35 is provided so as to be able to turn. The washing water nozzle 35 is formed in a substantially L shape, and washing water is sprayed onto the wafer W from the tip portion.

  Next, in addition to FIGS. 1 and 2, the holding table will be described with reference to FIG. FIG. 3 is a perspective view of the holding table of the present embodiment. The holding table 11 includes a central holding part (plate-like object holding part) 41 formed of a porous member, and an outer peripheral holding part 42 formed surrounding the central holding part 41. The center holding part 41 and the outer periphery holding part 42 are provided with a center holding surface (holding surface) 41a and an outer periphery holding surface 42a which are circular in a top view, and are formed concentrically.

  The diameter of the central holding surface 41a is substantially the same as the diameter of the wafer W or slightly smaller than the wafer W. The diameter of the outer peripheral holding surface 42a is larger than that of the wafer W, and the back surface of the protective tape T on the outer periphery of the wafer W is placed on the outer peripheral holding surface 42a. Further, the outer peripheral holding surface 42a is formed to have a diameter larger than the inner diameter of the annular frame F, and a region along the inner periphery of the annular frame F is placed on the outer peripheral holding surface 42a via the protective tape T. The diameter of the outer peripheral holding surface 42a is smaller than that of the protective tape T, and the upper surface of the holding table 11 is entirely covered with the protective tape T.

  The center holding part 41 is connected to a suction source 43 (not shown in FIGS. 1 and 3) through a suction path 42b formed in the outer periphery holding part 42. Therefore, in the central holding portion 41, the back surface of the wafer W is sucked and held via the protective tape T by the negative pressure generated on the central holding surface 41a.

  A communication groove 44 is formed in the outer peripheral holding surface 42a. In the communication groove 44, two circular grooves 44a that are concentric and have different diameters and four linear grooves 44b that connect the two circular grooves 44a are formed. Accordingly, the two circular grooves 44a and the four linear grooves 44b communicate with each other so that air flows. The center of each circular groove 44a coincides with the center of the central holding surface 41a and the outer peripheral holding surface 42a.

  Each linear groove 44b is formed every 90 ° in the circumferential direction of the outer peripheral holding surface 42a and extends in the radial direction. The inner end of each linear groove 44b is formed so as to communicate with the central holding portion 41 made of a porous member. Accordingly, the suction force from the central holding portion 41 acts in communication with the communication groove 44, and the protective tape T on the outer peripheral holding surface 42 a is sucked and held by the communication groove 44.

  In the above configuration, when the protective film Ra is formed on the surface (upper surface) of the wafer W, first, the protective tape T is attached to the annular frame F and the wafer W, and the wafer W is attached to the annular frame F via the protective tape T. Is supported and integrated. Thereafter, the wafer W supported by the annular frame F is transported and placed on the holding table 11 with the wafer W facing upward and the protective tape T positioned in the lower side of the wafer W. After the mounting, an electromagnetic valve (not shown) is operated to connect the suction source 43 and the communication path 42b, and the back surface (lower surface) of the wafer W is connected to the central holding surface via the protective tape T with the central holding portion 41 as a negative pressure. The suction is held at 41a.

  Thus, at the same time as the suction force acts on the central holding surface 41a, the central holding portion 41 communicates with the straight groove 44b of the communication groove 44. Therefore, the inside of the straight groove 44b and the circular groove 44a also becomes negative pressure and the central holding portion. The suction force from 41 communicates with the communication groove 44. With this suction force, the back surface (lower surface) of the protective tape T on the outer periphery of the wafer W is sucked and held by the outer peripheral holding surface 42a. At this time, the protective tape T comes into the communication groove 44 and follows, and the protective tape T is caught by the communication groove 44 and can be held while restricting the movement of the protective tape T and the wafer W. .

  After the wafer W is sucked and held on the holding table 11, the liquid resin supply nozzle 31 is turned to position the dropping portion 31 c above the center of the wafer W. In this state, when the liquid resin R is dropped onto the center of the surface of the wafer W, the holding table 11 is rotated about the vertical direction by the electric motor 20, and centrifugal force acts on the liquid resin R. By this centrifugal force, the liquid resin R is spread over the entire surface of the wafer W, and a protective film Ra made of the liquid resin R is formed. At this time, the back surface side of the wafer W is sucked and held by the central holding portion 41, and the back surface side of the protective tape T on the outer periphery of the wafer W is sucked and held by the outer periphery holding portion 42. 11, the wafer W is restricted from being displaced.

  The wafer W on which the protective film Ra is formed is placed on a chuck table (not shown) and laser processing is performed. At the time of laser processing, since the surface of the wafer W is covered with the protective film Ra, debris does not directly adhere to the surface of the wafer W. After the laser processing, the processed wafer W is held on the holding table 11 and cleaned. At the time of cleaning, the holding table 11 rotates at high speed while spraying cleaning water from the cleaning water nozzle 35. By spraying cleaning water onto the surface of the wafer W, the protective film Ra to which debris has adhered is washed away from the processed wafer W.

  According to such an embodiment, the protective tape T located on the outer peripheral side of the wafer W and inside the annular frame F can be sucked and held via the communication groove 44. Thus, the state where the wafer W and the annular frame F are held on the holding table 11 can be stably maintained without using a clamping mechanism for clamping the annular frame F. In other words, it is possible to eliminate the clamping mechanism for the annular frame F around the holding table 11, and it is possible to eliminate operations such as removal and cleaning of the liquid resin R adhering to the clamping mechanism. As a result, it is possible to reduce the burden required for maintenance such as cleaning, shorten the work time, and improve work efficiency.

  In addition, by holding the suction by the communication groove 44, the annular frame F can be stably held even when the outer peripheral side of the holding table 11 is dimensioned so that it does not protrude from the outer periphery of the annular frame F or the protective tape T. it can. As a result, the entire upper surface of the holding table 11 is covered with the annular frame F and the protective tape T, and the liquid resin R can be prevented from entering between the protective tape T and the upper surface of the holding table 11.

  In addition, since the linear groove 44b of the communication groove 44 communicates with the central holding portion 41 made of a porous member, suction in the communication groove 44 can be performed using suction in the central holding portion 41. Thereby, a dedicated flow path for connecting the communication groove 44 and the suction source 43 can be omitted, and the configuration can be simplified.

  Here, a configuration in which the porous member of the central holding portion 41 is expanded to the formation region of the communication groove 44 instead of the communication groove 44 is assumed as a comparative structure. In this comparative structure, the protective tape T in the region sucked and held by the communication groove 44 in the above embodiment is sucked and held by the porous member. Since many fine holes are formed in the porous member, the protective tape T is not in contact with the porous member for the region where the holes are formed. In this regard, in the above-described embodiment, the protective tape T enters and follows the communication groove 44, and the protective tape T comes into contact with the inner surface of the communication groove 44 and the upper surface of the outer peripheral holding portion 42. Therefore, compared with the comparative structure, the above embodiment can increase the contact area of the protective tape T with the holding table 11, and increase the frictional resistance to fix the protective tape T by the holding table 11. The power can be increased.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, direction, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, the shape of the communication groove 44 is not limited to the shape described in the above embodiment, and the linear groove 44b and the circular groove 44a may be increased or decreased, or may be formed by a groove extending in a wave shape in a top view. Good.

  As described above, the present invention has an effect that the burden of maintenance can be reduced, and in particular, protection for holding a plate-like object attached in an annular frame via a protective tape with a holding table. It is useful for a film forming apparatus.

DESCRIPTION OF SYMBOLS 10 Protective film formation apparatus 11 Holding table 20 Electric motor (rotation drive part)
21 Rotating shaft 30 Liquid supply means 31 Liquid resin supply nozzle 41 Center holding part (plate-like object holding part)
41a Center holding surface (holding surface)
42 outer periphery holding portion 42a outer periphery holding surface 44 communication groove F annular frame R liquid resin Ra protective film T protective tape W wafer (plate-like material)

Claims (1)

A holding table for holding a plate-like object attached in an annular frame via a protective tape on the upper surface, and a liquid resin supply nozzle for supplying a liquid resin to the surface of the plate-like object held by the holding table Liquid supply means;
A rotation driving unit that rotates the vertical direction with respect to the upper surface of the holding table as a rotation axis, and spreads the liquid resin supplied to the surface of the plate-like material over the entire surface of the plate-like material, A protective film forming apparatus for forming a protective film made of a liquid resin on the plate, wherein the holding table is formed of the porous member having a holding surface for sucking and holding the back surface of the plate-like material through the protective tape. An object holding part, and an outer periphery holding part that surrounds the plate-like object holding part and has an outer periphery holding surface that holds at least the back surface of the protective tape on the outer periphery of the plate-like object,
A communication groove communicating with the porous member of the plate-like object holding part is formed on the outer peripheral holding surface of the outer peripheral holding part, and a suction force from the porous member communicates with the communication groove,
The plate-like object is sucked and held by the plate-like object holding portion, and at least the back surface of the protective tape on the outer periphery of the plate-like object is sucked and held by the outer periphery holding portion by the suction force communicating with the communication groove. A protective film forming apparatus characterized in that a holding table is rotated to form a protective film on the surface of the plate-like object.

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