JP4675213B2 - Suction pad for semiconductor wafer - Google Patents

Description

  The present invention relates to a suction pad for a semiconductor wafer that is attached to a robot, an aligner, or the like in a pre-process of a semiconductor manufacturing process and holds a semiconductor wafer by suction.

  Semiconductor manufacturing processes (also called wafer processes) are classified into pre-processes consisting of doping such as ion implantation, formation of insulating films, lithography and etching, and post-processes consisting of back-grinding and dicing. In order to convey the semiconductor wafer and adjust the orientation, an expensive suction pad is attached to a dedicated robot (see Patent Documents 1 and 2).

  Although the suction pad is not shown in the drawing, the PEEK resin plate is cut into a substantially circular dish shape and is connected to the vacuum device of the robot. The vacuum device is used for driving the vacuum device. Based on this, the back surface of the semiconductor wafer is sucked and held.

By the way, in the pre-process of the semiconductor manufacturing process, the presence or absence of particles of about several tens to several hundreds of nanometers is a major problem that affects the yield of products. In view of this point, the conventional suction pad is formed so that carbon fibers exhibiting an antistatic function are kneaded so that particles are not sucked and transferred to the semiconductor wafer.
Japanese Patent Laid-Open No. 2004-174686 JP 2004-153157 A

  In the conventional suction pad for semiconductor wafers, conductive carbon fibers are randomly kneaded into PEEK resin as described above, so when cutting, the ends of the carbon fibers are exposed and the semiconductor wafer is shaved, There is a problem that short carbon fibers fall off and generate particles.

  The present invention has been made in view of the above, and an object of the present invention is to provide a suction pad for a semiconductor wafer that can prevent damage to the semiconductor wafer and prevent generation of particles.

In the present invention, in order to solve the above-mentioned problem, it is injection-molded using a thermoplastic resin compound , and adsorbs and supports a semiconductor wafer,
A plate having rigidity, an inner rib formed on the surface of the plate and contacting the semiconductor wafer, an outer rib surrounding the inner rib and contacting the semiconductor wafer, and provided at the center of the plate The inner and outer ribs are aligned at the same height, including the intake holes communicating between the inner and outer ribs.
On the back of the plate, a ring-shaped reinforcing rib is formed around the intake hole,
The inner rib is composed of a plurality of fan ribs that protrude from the surface of the plate body and surround the air intake holes, and a plurality of arc ribs that protrude from the surface of the plate body and surround the plurality of fan ribs. The gap between the fan ribs and the arc ribs is formed to allow a gas to flow therethrough, and between the adjacent fan ribs and the fan ribs, a groove is formed to communicate with the air intake holes to flow the gas. The contact area to the semiconductor wafer is made larger than the contact area of the arc rib to the semiconductor wafer, the mounting hole is drilled in the fan rib, and the groove between the adjacent fan ribs communicates with the groove between the fan ribs. To form a groove for flowing gas,
The outer rib is formed to project endlessly at the peripheral edge of the plate body, and its lower end is aligned with the height of the reinforcing rib, and a gap is formed between the outer rib and the plurality of arc ribs for gas flow. It is characterized in that the.

The thermoplastic resin of the thermoplastic resin compound is preferably polybutylene terephthalate.
The antistatic property-imparting material of the thermoplastic resin compound is preferably an organic conductor.

Also, the strength can be increased by forming a plurality of reinforcing ribs on the plate.
Further, the inner rib includes a plurality of fan ribs that are formed to protrude from the plate body and surround the air intake holes, and a plurality of arc ribs that are formed to protrude from the plate body and surround the plurality of fan ribs. A gap through which gas flows can be formed between the fan rib and the arc rib.

In addition, a plurality of fan ribs can be arranged around the intake holes, and a groove can be formed between the fan ribs and the fan ribs so as to flow gas in communication with the intake holes.
Further, a plurality of arc ribs may be arranged around the air intake holes, and a groove may be formed between the arc ribs and the arc rib so as to communicate with the grooves between the fan ribs and allow gas to flow therethrough.

  Here, the semiconductor wafer in the claims is not particularly limited to 200 mm, 300 mm, 450 mm type, Si type or the like. The plate body can be formed in a circular shape, an elliptical shape, a rectangular shape, a triangular shape, a polygonal shape, or the like in plan view. Further, although it may be flat, it may be formed in a horizontally long cross-section with a substantially H shape, or may be formed in irregularities. The position and number of the inner ribs and the intake holes can be appropriately increased or decreased. The inner rib can be formed in various shapes such as a sector shape and a column shape. Furthermore, the outer rib may be a ring shape, a frame shape, or the like.

  According to the present invention, if a semiconductor wafer suction pad is injection-molded using a thermoplastic resin compound, a skin layer can be formed on the surface of the semiconductor wafer suction pad. It is possible to prevent the problem that the semiconductor wafer is scraped due to exposure and the carbon fiber or the like falls off to generate particles.

According to the present invention, when a molten thermoplastic resin compound is injected into a mold, the heat of the thermoplastic resin compound is taken into the mold, and a thin skin layer is formed on the exposed surface of the suction pad for a semiconductor wafer. It becomes. Therefore, if this skin layer is used for covering protection, it is possible to solve the problem that the end of the carbon fiber is exposed and the semiconductor wafer is shaved, or the short carbon fiber is dropped and generates particles. Moreover, since the suction pad for semiconductor wafers is manufactured by injection molding, the surface of the suction pad for semiconductor wafers is not roughened, and can be manufactured at low cost and in large quantities. Further, since the reinforcing rib is formed to protrude from the back surface of the plate, it is possible to impart rigidity or prevent sinking during molding to prevent dents. Further, since the contact area of each fan rib is wider than the contact area of each arc rib, the posture of the semiconductor wafer can be stabilized. Further, in addition to forming outer ribs on the peripheral edge of the plate body, reinforcing ribs, fan ribs, and arc ribs are integrated on the front and back of the plate body to increase the strength, so that it is possible to prevent deformation of the suction pad for semiconductor wafers.
Further, if the thermoplastic resin of the thermoplastic resin compound is polybutylene terephthalate, it is possible to improve the wear resistance and low dust generation of the semiconductor wafer suction pad.
Furthermore, if the antistatic property imparting material of the thermoplastic resin compound is an organic conductor, the generation of particles can be suppressed.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the suction pad for a semiconductor wafer in this embodiment has a volume resistance value of 1E + 0 to 1E + 13 (Ω · cm ) And a rigid plate body 1, an inner rib 10 formed on the plate body 1, and an outer side surrounding the inner rib 10 around the plate body 1. The rib 20 and the intake hole 2 communicating between the inner rib 10 and the outer rib 20 are integrally provided, and set on an aligner (theta) robot (not shown) to hold the back surface of the semiconductor wafer W by suction.

  The thermoplastic resin compound is prepared by mixing a compounding agent such as an antistatic property-imparting material with a thermoplastic resin. Examples of the thermoplastic resin of this thermoplastic resin compound include PBT (polybutylene terephthalate), PEEK, PEI, AAS, PC, ABS, PPE, LCP, PP, PE, PAI, thermoplastic PI, modified products, alloys, and the like. can give. Among these, it is preferable to use PBT having excellent wear resistance, low dust generation, and dimensional stability.

  The antistatic property-imparting material added to the thermoplastic resin includes conductive carbon fiber, carbon whisker, metal fiber, metal whisker, carbon powder, graphite powder, organic conductor (polyaniline, polypyrrole, polythiophene, ion Conductive system). Among these, it is preferable to employ an organic conductor from the viewpoint of preventing particles.

  The plate body 1 is formed in a flat circular shape, and a round suction hole 2 is drilled in the center of the plate body 1 in the thickness direction. The suction hole 2 is a vacuum of a robot used in a pre-process of the semiconductor manufacturing process. It is connected to the device via a tube or the like. In the plate 1, a ring-shaped reinforcing rib 3 for improving the rigidity of the suction pad is formed on the back surface so as to protrude from the intake hole 2, and the lower end portion of the reinforcing rib 3 is the same height as the lower end portion of the outer rib 20. Aligned. Further, the inner rib 10 and the outer rib 20 are formed at the same height on the surface of the plate 1, and the inner rib 10 and the outer rib 20 are in contact with the back surface of the semiconductor wafer W without any gap.

  The inner rib 10 protrudes from the surface of the plate body 1 and surrounds the air intake hole 2, and the inner rib 10 protrudes from the surface of the plate body 1 and surrounds the plurality of fan ribs 11 from the outside. An arc rib 12 is provided, and a gap 13 through which air flows is defined between the plurality of fan ribs 11 and the arc rib 12. The plurality of fan ribs 11 are arranged around the air intake hole 2, and a groove 14 that communicates with the air intake hole 2 and distributes air is defined between the adjacent fan ribs 11. The flat fan ribs 11 are provided with attachment holes 15 for the robot in the thickness direction.

  The plurality of arc ribs 12 are arranged so as to draw a circle around the intake hole 2, and air is communicated between the adjacent flat arc ribs 12 and the arc ribs 12 to the grooves 14 between the fan ribs 11. A groove 14 to be circulated is defined.

  The outer rib 20 projects endlessly at the peripheral edge of the plate body 1 and extends in the vertical thickness direction. The outer rib 20 has a flat ring shape, and in other words, the reinforcing rib 3 and the inner rib 10, in other words, the plurality of arc ribs 12 are disposed on the outer side. Siege from. The outer rib 20 has flat upper and lower end portions, and a gap 13 through which air is circulated is formed in a ring shape between the plurality of arc ribs 12.

  The semiconductor wafer W is sliced into a disk having a diameter of 300 mm (12 inches), for example, and an oxide film is laminated on the surface thereof, and is transferred by a robot between the substrate storage container and the processing apparatus in the previous process, Processing such as doping such as ion implantation, formation of an insulating film, lithography, etching, and the like is performed. Positioning orientation flats and notches are selectively formed on the peripheral edge of the semiconductor wafer W.

In the above description, if the vacuum device of the robot is driven after the back surface of the semiconductor wafer W is mounted and supported on the semiconductor wafer suction pad, the air between the semiconductor wafer suction pad and the semiconductor wafer W becomes a plurality of gaps 13 and The air is exhausted to the outside from the groove 14 via the air intake hole 2, and the semiconductor wafer suction pad sucks and holds the semiconductor wafer W without a gap 13 by this exhaust.
At this time, since the inner rib 10 and the outer rib 20 are substantially the same height, air does not leak from the suction pad for semiconductor wafer, thereby preventing the semiconductor wafer W from being sucked.

  According to the above, when the molten thermoplastic resin compound is injected into the mold, the heat of the thermoplastic resin compound is taken into the mold, and the thin skin layer 30 is easily formed on the exposed surface of the suction pad for semiconductor wafer. The Rukoto. Therefore, if this skin layer 30 is used for covering protection, it is possible to surely solve the problem that the end of the carbon fiber is exposed and the semiconductor wafer W is shaved, or the short carbon fiber is dropped and generates particles. it can.

  Moreover, since the suction pad for semiconductor wafer is manufactured by injection molding instead of cutting, the surface of the suction pad for semiconductor wafer is not roughened, and can be manufactured at low cost and in large quantities. Specifically, by injection-molding the suction pad for a semiconductor wafer, it is possible to reduce the price from several hundred thousand yen to a price of several tens of thousands of yen or less. In addition, since the volume resistance value of the thermoplastic resin compound is in the range of 1E + 0 to 1E + 13 (Ω · cm), it is possible to prevent charging and suppress the generation of particles or transfer.

  Further, since the reinforcing ribs 3 are formed so as to protrude from the back surface of the plate body 1, it is possible to impart rigidity and prevent sinking (also referred to as a sync mark) during molding to prevent dents. Further, since the contact area of each fan rib 11 is wider than the contact area of each arc rib 12, stabilization of the posture of the semiconductor wafer W can be greatly expected. Further, in addition to forming the outer rib 20 on the peripheral edge of the plate body 1, the reinforcing rib 3, the fan rib 11 and the arc rib 12 are integrated on the front and back of the plate body 1 to increase the strength. It can be expected to prevent deformation.

  In the above-described embodiment, the reinforcing rib 3 and the outer rib 20 are formed on the back side of the plate body 1. However, the reinforcing rib 3 may be made shorter or lower than the outer rib 20 or the reinforcing rib unless particularly hindered. 3 may be made shorter and lower than the outer rib 20, or these 3 and 20 may be omitted. Further, the suction pad for semiconductor wafer may be set not on the aligner but on a robot arm or the like.

  Further, in the above embodiment, the inner rib 10 is formed so as to protrude from the surface of the plate body 1 and surround the intake holes 2, and the plurality of fan ribs 11 formed to protrude from the surface of the plate body 1. Although formed from a plurality of arc ribs 12 surrounding from the outside, a plurality of arc ribs 12 projecting from the surface of the plate body 1 to surround the intake holes 2 and a plurality of arc ribs 12 projecting from the surface of the plate body 1 are formed. You may form from the several fan rib 11 which surrounds the circular arc rib 12 from the outer side. Furthermore, the inner rib 10 may be a cylindrical rib that is formed in a plurality of protrusions on the surface of the plate body 1 and is surrounded by the outer rib 20.

It is a plane explanatory view showing an embodiment of a suction pad for semiconductor wafers concerning the present invention. It is a section explanatory view showing an embodiment of a suction pad for semiconductor wafers concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plate body 2 Air intake hole 3 Reinforcement rib 10 Inner rib 11 Fan rib 12 Arc rib 13 Gap 14 Groove 20 Outer rib 30 Skin layer W Semiconductor wafer

Claims (3)

A semiconductor wafer suction pad that is injection-molded using a thermoplastic resin compound and sucks and supports a semiconductor wafer,
A plate having rigidity, an inner rib formed on the surface of the plate and contacting the semiconductor wafer, an outer rib surrounding the inner rib and contacting the semiconductor wafer, and provided at the center of the plate The inner and outer ribs are aligned at the same height, including the intake holes communicating between the inner and outer ribs.
On the back of the plate, a ring-shaped reinforcing rib is formed around the intake hole,
The inner rib is composed of a plurality of fan ribs that protrude from the surface of the plate body and surround the air intake holes, and a plurality of arc ribs that protrude from the surface of the plate body and surround the plurality of fan ribs. The gap between the fan ribs and the arc ribs is formed to allow a gas to flow therethrough, and between the adjacent fan ribs and the fan ribs, a groove is formed to communicate with the air intake holes to flow the gas. The contact area to the semiconductor wafer is made larger than the contact area of the arc rib to the semiconductor wafer, the mounting hole is drilled in the fan rib, and the groove between the adjacent fan ribs communicates with the groove between the fan ribs. To form a groove for flowing gas,
The outer rib is formed to project endlessly at the peripheral edge of the plate body, and its lower end is aligned with the height of the reinforcing rib, and a gap is formed between the outer rib and the plurality of arc ribs for gas flow. A suction pad for semiconductor wafers.   The suction pad for a semiconductor wafer according to claim 1, wherein the thermoplastic resin of the thermoplastic resin compound is polybutylene terephthalate.   The suction pad for a semiconductor wafer according to claim 1, wherein the antistatic property imparting material of the thermoplastic resin compound is an organic conductor.

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