JP2013016621A - Sticking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sticking method capable of sticking a wafer to an adhesive tape without causing any damage on a device.SOLUTION: The sticking method of sticking a planar object to an adhesive tape having a polymer film as a base material includes an adhesive tape sticking step for sticking at least the outer peripheral part of the planar object to an adhesive tape in a gas atmosphere having a molecular weight smaller than those of oxygen and nitrogen, and an adhesion step for making the planar object adhere to the adhesive tape by sucking the adhesive tape side and discharging a gas having a small molecular weight and sandwiched by the adhesive tape and the planar object by means of an activation diffusion mechanism.

Description

  The present invention relates to an attaching method for attaching a plate-like object such as a wafer to an adhesive tape.

  A wafer formed by dividing a plurality of devices such as IC and LSI on the surface by dividing lines is ground on the back surface by a grinding device and thinned to a predetermined thickness, and then individually processed by a dicing device or a laser processing device. These devices are widely used in various electric devices such as mobile phones and personal computers.

  Among such various devices, delicate devices such as CMOS image sensors and MEMS (Micro Electro Mechanical Systems) devices are disliked by water, and are therefore divided into individual devices by a laser processing apparatus.

  Since the wafer is divided into individual devices and then transported to the next bonding process or the like, the back surface is affixed to a dicing tape which is an adhesive tape, and the dicing tape is formed by an annular frame having an opening for accommodating the wafer. Is held by a dicing apparatus or a chuck table of a laser processing apparatus in a state where the outer periphery of the substrate is supported (see, for example, JP-A-2007-149820).

  Japanese Patent Laid-Open No. 6-177243 proposes a tape applicator for integrating an annular frame and a semiconductor wafer with an adhesive tape. In this tape applicator, the tape attaching movable roller slides on the wafer and the annular frame placed on the holding table, thereby integrating the annular frame and the wafer with the adhesive tape.

JP 2007-149820 A JP-A-6-177243

  However, when a wafer on which a delicate device such as a CMOS image sensor or a MEMS device is formed is stuck to the adhesive tape, there is a problem that the device may be damaged if the wafer is pressed against the adhesive tape with a roller.

  This invention is made | formed in view of such a point, The place made into the objective is providing the sticking method which can stick a wafer to an adhesive tape, without damaging a device.

  According to the present invention, there is provided a sticking method for sticking a plate-like material to a pressure-sensitive adhesive tape having a polymer film as a base material, wherein at least an outer peripheral portion of the plate-like material is contained in a gas atmosphere having a molecular weight smaller than oxygen and nitrogen. Adhesive tape pasting process to stick to the adhesive tape, and the adhesive tape side is sucked and the gas with a low molecular weight sandwiched between the adhesive tape and the plate-like material is discharged by the activation diffusion mechanism to remove the plate-like material. An adhesion method characterized by comprising an adhesion step for adhering to an adhesive.

  Preferably, the low molecular weight gas is composed of helium. Preferably, the outer periphery of the adhesive tape is supported by an annular frame having an opening for accommodating a plate-like object.

  According to the present invention, the plate-like material is brought into close contact with the adhesive tape by utilizing the activated diffusion mechanism which is a characteristic of the polymer film, so that the plate-like material is applied to the adhesive tape without applying a pressing force to the plate-like material. Can be attached without damaging the device formed on the plate.

  In particular, after carrying out the adhesive tape sticking process of sticking at least the outer periphery of the plate-like material to the adhesive tape in a gas atmosphere with a low molecular weight, when the adhesive tape side is sucked, the plate-like material is activated in a short time by the activated diffusion mechanism. Can be adhered to the adhesive tape.

It is a longitudinal cross-sectional view of the sticking apparatus suitable for implementing the sticking method of this invention. It is a longitudinal cross-sectional view which shows the detail of an air cylinder part. It is a surface side perspective view of a semiconductor wafer. It is a perspective view of the state where the peripheral part of the adhesive tape was stuck on the annular frame. It is a perspective view of a chuck table mechanism. It is a longitudinal cross-sectional view of the state which set the semiconductor wafer and the adhesive tape in the predetermined location of the sticking apparatus. It is a longitudinal cross-sectional view explaining an adhesive tape sticking process. It is a longitudinal cross-sectional view explaining a contact | adherence process. It is a disassembled perspective view explaining the contact | adherence process shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown a longitudinal sectional view of a contact apparatus 2 suitable for carrying out the contact method of the present invention. The contact device 2 defines a chamber 6 in the housing 4.

  A helium inlet 8 is formed in the upper wall 4 a of the housing 4, and the helium inlet 8 is connected to a helium supply source 12 via a switching valve 10. An exhaust port 14 is formed in the bottom wall 4 b of the housing 4. The exhaust port 14 communicates with the atmosphere via the switching valve 16.

  A chuck table mechanism 18, which will be described in detail later, is mounted on the bottom wall 4 b of the housing 4. The chuck table mechanism 18 is connected to a negative pressure suction source 22 through a suction port 19 and a switching valve 20 formed in the bottom wall 4b.

  A piston rod 26 of an air cylinder 24 is fixed to the upper wall 4 a of the housing 4. As shown in FIG. 2, the air cylinder 24 accommodates a piston 26a connected to a piston rod 26, and a head-side chamber 25a and a rod-side chamber 25b are defined by the piston 26a.

  The head side chamber 25 a is connected to the high pressure air source 32 via the air passage 27 a and the switching valve 30, and the rod side chamber 25 b is connected to the high pressure air source 32 via the air passage 27 b and the switching valve 30.

  An annular protrusion 28 is formed integrally with the air cylinder 24. A suction path 29 is formed across the air cylinder 24 and the annular protrusion 28, and the suction path 29 communicates with the suction source 22 via the switching valve 34. By switching the switching valve 34 and connecting the suction path 29 to the suction source 22, a negative pressure acts on the suction surface (lower surface) 28 a of the annular protrusion 28.

  Referring to FIG. 3, a front side perspective view of the semiconductor wafer 11 is shown. The semiconductor wafer 11 is made of a silicon wafer whose back surface 11b is ground to a thickness of about 50 μm. A plurality of division lines (streets) 13 are formed in a lattice shape on the front surface 11a. A device 15 such as a MEMS device is formed in each region partitioned by the scheduled division line 13.

  Referring to FIG. 4, a perspective view of a state where the outer peripheral portion of the adhesive tape T is attached to the annular frame F so as to close the opening of the annular frame F is shown. The pressure-sensitive adhesive tape T is formed by applying an acrylic pressure-sensitive adhesive layer on a base material formed of a polymer film such as polyvinyl chloride.

  Referring to FIG. 5, a perspective view of the chuck table mechanism 18 is shown. A chuck table 40 is mounted on the support base 38 of the chuck table mechanism 18. The chuck table 40 has an annular frame body 42 and a suction holding portion 44 formed of porous ceramics or the like surrounded by the frame body 42.

  A suction path connected to the negative pressure suction source 22 shown in FIG. 1 is formed at the center of the support base 38. By operating the negative pressure suction source 22, the chuck table 40 has a suction holding portion 44. Then, the wafer 11 is sucked and held through the adhesive tape T.

  Four frame clamps 46 are attached to the support base 38 at a distance of 90 degrees in the circumferential direction. Each frame clamp 46 has a pair of air cylinders (not shown) fixed to the support base 38.

  The piston rod 48 of the air cylinder is connected to the support member 50. An air actuator 52 is fixed to the support member 50, and the air actuator 52 has a rotating shaft 54 that is rotated 90 degrees.

  An L-shaped clamp claw (pressing member) 56 is fixed to the rotating shaft 54. When the rotary shaft 54 is rotated by the air actuator 52, the pressing member 56 is rotated between a clamp position for clamping the annular frame F and an open position shown in FIG.

  Hereinafter, the sticking method of the present invention will be described in detail with reference to FIGS. First, as shown in FIG. 6, the suction path 29 formed in the air cylinder 24 is connected to the suction source 22 to apply a negative pressure to the suction surface 28a of the annular protrusion 28, whereby the device 15 of the wafer 11 is formed. The outer peripheral surplus area which is not sucked is held. On the other hand, the adhesive tape T supported by the annular frame F shown in FIG. 4 is placed on the chuck table 40, and the annular frame F is clamped and fixed by the frame clamp 46.

  In this state, helium (He) gas pressurized from the helium inlet 8 is introduced into the chamber 6 while the exhaust port 14 is opened to the atmosphere. When the inside of the chamber 6 is filled with helium gas, as shown in FIG. 7, the air cylinder 27 is operated to extend the piston rod 26, and the outer peripheral portion of the wafer 11 sucked and held by the annular protrusion 28 is attached to the adhesive tape. An adhesive tape sticking step is performed in which the outer peripheral portion of the wafer 11 is stuck to the adhesive tape T by being pressed against T.

  After performing the adhesive tape attaching process, as shown in FIG. 8, the switching valve 16 is switched to seal the exhaust port 14, the air cylinder 24 is operated, the piston rod 26 is contracted, and the annular protrusion 28 is moved from above the wafer 11. Retract upward.

  While introducing helium gas into the chamber 6 through the helium inlet 8, the suction holder 44 of the chuck table 40 is connected to the negative pressure suction source 22 through the suction port 19. When the suction holding portion 44 of the chuck table 40 is sucked by the negative pressure suction source 22 at a negative pressure of 0.1 to 0.3 atm, it is sandwiched between the adhesive tape T and the wafer 11 by the activation diffusion mechanism of the polymer film. The helium gas having a low molecular weight is discharged, and the entire wafer 11 can be adhered to the adhesive tape T.

  This activated diffusion mechanism of helium gas is considered to occur in the following process. First, helium molecules are condensed on the surface of the pressure-sensitive adhesive tape T on the higher pressure side, and then helium molecules are dissolved inside the pressure-sensitive adhesive tape T. The concentration of helium dissolved in the adhesive tape T is proportional to the pressure of the introduced helium gas.

  The dissolved helium molecules are diffused toward the lower concentration by the concentration gradient as a driving force, and helium molecules reaching the opposite side of the adhesive tape T are desorbed from the tape surface. Gas permeation by the activated diffusion mechanism consists of three processes: dissolution → diffusion → desorption.

  Referring to FIG. 9, there is shown a schematic perspective view illustrating this contact process. The adhesive tape T supported by the annular frame F is mounted on the chuck table 40, and the annular frame F is clamped by the pressing member 56 by rotating the pressing member 56 of the frame clamp 46 by 90 degrees.

  In this state, after carrying out the adhesive tape sticking step shown in FIG. 7, the negative pressure suction source 22 is introduced while introducing helium gas pressurized from the helium inlet 8 into the chamber 6 as shown in FIG. 8. When the suction holding portion 44 of the chuck table 40 is sucked by the above-described activation diffusion mechanism, the helium gas having a small molecular weight sandwiched between the adhesive tape T and the wafer 11 is discharged, and the entire back surface of the wafer 11 is discharged in a very short time. Can be adhered to the adhesive tape T.

  The adhesive tape T was formed by disposing an acrylic adhesive material on a polyvinyl chloride substrate. While introducing the helium gas into the chamber 6, the adhesive tape T is held by the chuck table 40, and the outer peripheral portion of the semiconductor wafer 11 is pressed against the adhesive tape T by the annular protruding portion 28 of the air cylinder 24. The adhesive tape sticking process which sticks to the adhesive tape T was implemented.

  After carrying out the adhesive tape sticking process, the helium gas is introduced into the chamber 6 while the negative pressure of the negative pressure suction source 22 is set to -70 kPa to -90 kPa and the suction is continued for 10 minutes to 20 minutes. The helium molecule bubbles between the wafer 11 and the adhesive tape T were completely removed by the diffusion mechanism, and the entire back surface of the wafer 11 was in close contact with the adhesive tape T.

  The adhesive tape T was formed by disposing an acrylic adhesive material on a polyolefin base material. While introducing helium gas into the chamber 6, an adhesive tape adhering step was performed in which the outer peripheral portion of the semiconductor wafer 11 was pressed against the adhesive tape T and adhered.

  Subsequently, while introducing the helium gas into the chamber 6, the negative pressure suction source 22 was set to −70 kPa to −90 kPa, and the suction was continued for 20 minutes to 40 minutes. The bubbles of helium molecules between the tape T and the tape T were completely removed, and the entire back surface of the wafer 11 was in close contact with the adhesive tape T.

2 Adhering device 6 Chamber 8 Helium inlet 11 Semiconductor wafer 12 Helium gas supply source 14 Exhaust port 18 Chuck table mechanism 22 Negative pressure suction source 24 Air cylinder 28 Annular protrusion 40 Chuck table T Adhesive tape F Annular frame

Claims (3)

A sticking method for sticking a plate to a pressure-sensitive adhesive tape having a polymer film as a base material,
An adhesive tape attaching step of attaching at least the outer peripheral portion of the plate-like material to the adhesive tape in a gas atmosphere having a molecular weight smaller than oxygen and nitrogen;
An adhesion step of sucking the adhesive tape side and discharging a gas having a small molecular weight sandwiched between the adhesive tape and the plate-like material by an activation diffusion mechanism to closely adhere the plate-like material to the adhesive tape;
The sticking method characterized by comprising.   The sticking method according to claim 1, wherein the gas having a low molecular weight is composed of helium.   The sticking method of Claim 1 or 2 with which the outer periphery of an adhesive tape is supported by the annular frame which has an opening part which accommodates a plate-shaped object.

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