JP2013058800A - Adhesive sheet for fragile member processing and processing method of fragile member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet for fragile member processing that is suitably used for a processing method of a fragile member which stably holds the fragile member when the fragile member, such as a semiconductor wafer, is transported and processing, such as a rear surface grinding, is performed and enables the fragile member to be peeled without causing the damage after the required processing is finished.SOLUTION: An adhesive sheet for fragile member processing according to the invention is composed of: a lamination film base material which has a first film and a second film and is formed by fastening peripheral parts of the first and second films and placing the two films in contact with each other in an airtight manner to be integrated at an internal region enclosed by fastening parts; and an adhesive layer formed on both outer surfaces of the lamination film base material.

Description

  The present invention relates to an adhesive for processing a brittle member suitably used in a processing method for a brittle member, including various processing steps represented by processing such as conveyance of a brittle member such as a semiconductor wafer and back grinding of a semiconductor wafer. Regarding the sheet. Moreover, this invention relates to the processing method of a brittle member.

  With the spread of IC cards in recent years, thinning of wafers as constituent members has been promoted. It has been demanded to reduce the thickness of a conventional wafer having a thickness of about 350 μm to 50 to 100 μm or less.

  As the wafer that is a brittle member becomes thinner, the risk of breakage increases during processing and transportation. For this reason, when grinding a wafer to an extremely thin thickness or transporting an extremely thin wafer, the wafer is fixed and protected on a hard plate such as a glass plate or an acrylic plate with a double-sided adhesive sheet. It is desirable to proceed.

  However, in the method of bonding a wafer and a hard plate with a double-sided pressure-sensitive adhesive sheet, the wafer may be broken when the wafer is peeled off from the hard plate after a series of steps. When peeling a laminate formed by laminating two thin-layer products, it is necessary to bend either one of the thin-layer products or both. However, since it is impossible or difficult to curve the hard plate, the wafer side must be curved. For this reason, a fragile wafer is distorted and cracked.

  As a means for solving such a problem, a method of performing separation while reducing deformation of the wafer as much as possible, a method of performing separation after reinforcing the wafer by laminating a protective film on the wafer, and the like As a means of fixing the wafer to the hard plate, there is a method of using a pressure-sensitive adhesive or double-sided pressure-sensitive adhesive tape whose adhesive force can be controlled, and performing peeling after reducing the adhesive force by an appropriate means such as foaming of the adhesive during peeling Various proposals have been made (Patent Documents 1 to 5).

Patent Document 6 discloses a method for protecting a brittle member using a relatively rigid resin film without using a hard plate.
JP 2004-153227 A JP 2005-116678 A JP 2003-324142 A JP 2005-277037 A International Patent Publication WO2003 / 049164 JP 2004-63678 A

  When the wafer is held on a hard plate, the wafer side is deformed when the wafer is peeled off. For this reason, it is difficult to completely prevent the wafer from being damaged. In addition, when a special pressure-sensitive adhesive or double-sided pressure-sensitive adhesive tape designed to reduce the adhesive force by foaming or the like is used, the adhesive may remain on the wafer and contaminate the wafer. In the method proposed in Patent Document 6, since the rigid resin film side is deformed and peeled off from the wafer, the problem of wafer breakage can be solved. However, since it is a resin film, shape retention is not always sufficient, and the wafer may be damaged when the wafer is transferred.

  The present invention seeks to solve the problems associated with the prior art as described above. That is, the present invention can stably hold a brittle member when performing processing such as conveyance of a brittle member such as a semiconductor wafer or back grinding, and after the required processing is completed, It aims at providing the adhesive sheet for brittle member processing preferably used for the processing method of the brittle member which can be peeled without being damaged.

  The gist of the present invention aimed at solving such problems is as follows.

(1) Lamination having a first film and a second film, the peripheral edges of which are bound together, and the two films being hermetically tightly integrated in an inner region surrounded by the binding part A film substrate;
A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed on both outer surfaces of the laminated film substrate.

(2) The adhesive sheet for brittle member processing according to (1), wherein the coefficient of static friction between the inner surfaces of the laminated film substrate is 0.1 or more.

  In the present invention, a brittle member such as a semiconductor wafer is fixed to and protected by a hard plate via an adhesive sheet for processing a brittle member having a laminated film base material bonded only at the peripheral portion. The brittle member can be held without being deformed during transportation, storage, and processing of the material member. Further, after the required treatment, the brittle member can be easily separated from the hard plate by cutting the laminated film substrate, so that the brittle member can be easily peeled off and the brittle member is prevented from being damaged. .

  Hereinafter, while describing the processing method of the brittle member of this invention, referring to drawings about this invention, the adhesive sheet for brittle member processing of this invention is demonstrated more concretely.

  As shown in FIG. 1, in the brittle member processing method according to the present invention, the brittle member 2 is removably fixed to one side of the adhesive sheet 1 for brittle member processing, and the hard plate 3 is reattached to the other side. Fix in a peelable manner.

  Examples of the brittle member 2 include, but are not limited to, various semiconductor wafers such as a silicon wafer and a gallium / arsenic wafer, a ceramic plate, a glass plate, and a metal plate. Among these, the treatment method of the present invention is particularly preferably applied to a semiconductor wafer having a circuit formed on the surface. Furthermore, it can be preferably applied to a semiconductor wafer that has been subjected to backside grinding and has a very thin thickness and extremely low strength.

  The hard plate 3 functions to support and protect the brittle member 2 during transportation, storage, and processing. As the hard plate 3, for example, a glass plate, a quartz plate, an acrylic plate, a polyvinyl chloride plate, a polyethylene terephthalate plate, a polypropylene plate, a polycarbonate plate, or the like can be used. The hardness defined by ASTM D 883 of the hard plate 3 is preferably 70 MPa or more. The thickness of the hard plate 3 is usually about 0.1 to 10 mm, although it depends on the material. The diameter of the hard plate 3 is the same as or slightly larger than the diameter of the brittle member 2. Furthermore, as will be described later, when an ultraviolet curable adhesive is used as the adhesive layers 11a and 12a of the brittle member processing adhesive sheet 1, the hard plate 3 is formed of an ultraviolet transmissive material. .

  In the present invention, the brittle member 2 is fixed on the hard plate 3 via the adhesive sheet 1 for brittle member processing.

  The pressure-sensitive adhesive sheet 1 for processing a brittle member has a first film 11 and a second film 12, and a laminated film substrate 10 formed by binding the peripheral edges thereof, and both the laminated film substrate 10. It consists of adhesive layers 11a and 12a formed on the outer surface.

  As shown in the cross-sectional view of FIG. 1, the laminated film base material 10 includes a first film 11 and a second film 12, and a laminated film base material formed by binding these peripheral portions. can give. In FIG. 1, reference numeral 13 at the peripheral edge at the contact surface between the first film 11 and the second film 12 indicates the binding portion 13 between the first film 11 and the second film 12. In the normal state, the first film 11 and the second film 12 are airtightly closely integrated. That is, the laminated film substrate 10 is a laminated film in which two films are bound and fixed at the peripheral edge. The binding portion 13 is provided so as to be located outside the outer edge of the brittle member 2 to be stuck.

  The 1st film 11 and the 2nd film 12 will not be specifically limited if it is a resin film which has moderate softness | flexibility, Various resin films can be used. Examples of such resin films include polyolefins such as low density polyethylene, linear low density polyethylene, polypropylene, and polybutene, ethylene vinyl acetate copolymers, ethylene (meth) acrylic acid copolymers, and ethylene (meth) acrylic acid. Examples thereof include ethylene copolymers such as ester copolymers, polyesters such as polyethylene terephthalate and polyethylene naphthalate, and resin films such as polyvinyl chloride, acrylic rubber, polyamide, urethane, and polyimide. In addition, each of the film 11 and the film 12 may be a single layer or a laminate. Moreover, the film which gave the process of bridge | crosslinking etc. may be sufficient. Further, the first film 11 and the second film 12 may be a film obtained by forming a thermoplastic resin into a sheet by extrusion molding, or a film obtained by thinning and curing a curable resin by a predetermined means. May be used. Examples of the curable resin include a resin composition in which an energy ray-curable urethane acrylate oligomer is a main component, an acrylate monomer having a relatively bulky group is a diluent, and a photopolymerization initiator is blended as necessary. Used.

  The first film 11 and the second film 12 may be formed of the same type of resin film, or may be formed of different types of resin films as long as they can be bonded and closely integrated.

  The thickness of each of the first film 11 and the second film 12 is preferably 5 to 200 μm, more preferably 10 to 150 μm, and particularly preferably 20 to 100 μm. Therefore, the total thickness of the first film 11 and the second film 12 is preferably 10 to 400 μm, more preferably 20 to 300 μm, and particularly preferably 40 to 200 μm.

  The binding between the first film and the second film may be fusion by heat or adhesion by an adhesive. When using an adhesive, it is preferable to use a strong adhesive such as acrylic.

  The laminated film substrate 10 is formed by, for example, stacking the first film 11 and the second film 12 and thermocompression bonding the first film 11 and the second film 12 with a thermocompression bonding apparatus including a ring-shaped heating unit. Obtained. Moreover, the laminated film base material 10 can also be obtained by forming an adhesive layer in a ring shape on one film surface and laminating the other film. After manufacturing the laminated film substrate 10, the substrate may be cut along the outer diameter of the binding portion.

  The binding portion 13 between the first film 11 and the second film 12 is laminated as shown in a plan view (a plan view at the contact surface between the first film 11 and the second film 12) in FIG. Provided at the peripheral edge of the film substrate 10. The binding part 13 may be provided continuously on the entire periphery of the peripheral part of the laminated film substrate 10 or may be provided discontinuously. In the inner region surrounded by the binding portion 13, the first film 11 and the second film 12 are airtightly closely integrated.

  When the processing of the brittle member 2 in the present invention is back grinding of a semiconductor wafer, stress is applied to the semiconductor wafer in the shear direction (lateral direction), and at the same time, the laminated film substrate 10 is also subjected to the shear direction. Stress propagates. As a result, the film may slip on the contact surface between the first film 11 and the second film 12, and the film may be misaligned. When such a positional deviation of the film occurs, back surface grinding becomes impossible.

In order to prevent the positional displacement of the film as described above, the coefficient of static friction between the contact surfaces of the first film 11 and the second film 12, that is, the inner surfaces of the laminated film substrate 10, is preferably 0.1. Above, more preferably 0.15 or more, particularly preferably 0.2 or more. Here, the coefficient of static friction between the inner surfaces of the laminated film substrate 10 is a value measured in accordance with JIS K 7125 at the contact surface between the first film 11 and the second film 12. Static friction means the friction when exceeding the “threshold value” at the start of sliding, and the static friction coefficient is a coefficient obtained from the “threshold value” and is defined by μ _S = F _s / F _p . Here, μ _S is a static friction coefficient, F _s is a static friction force, and F _p is a normal force generated by the mass of the sliding piece. The measurement conditions for the static friction coefficient will be described more specifically with reference to the static friction coefficient measuring apparatus shown in FIG.

The static friction coefficient measuring device 20 shown in FIG. 6 includes a horizontal table 21, a sliding piece 22, and a drive mechanism (not shown) that moves the table 21 in the horizontal direction. The sliding piece 22 has a contact area (bottom area) of 40 cm ² (length of one side of 63 mm) and a bottom surface covered with a felt 22a, and has a total mass of 200 ± 2 g. The test films 23 and 24 are each one of the first film 11 and the second film 12, and the test film 23 is set so as to cover the bottom surface of the sliding piece 22. The size of the test film 23 is 63 mm × 80 mm, and the size of the test film 24 is 80 mm × 100 mm. The test films 23 and 24 are set so that the surfaces that are the contact surfaces of the first film 11 and the second film 12 come into contact with each other when the laminated film substrate 10 is configured. The sliding piece 22 on which the test film 23 is set is connected to a load cell 26 via a spring 25. The spring constant of the spring 25 is 0.2 N / mm. After the static friction coefficient measuring device 20 is configured as described above, the table 21 is moved horizontally at 100 mm / min, and the load is read by the load cell 26. From the measured value, the coefficient of static friction is calculated according to JIS K 7125.

  The surfaces of the first film 11 and the second film 12 may be subjected to blast treatment, corona treatment, coating treatment, plasma treatment, electron beam treatment, etc. in order to obtain a desired coefficient of static friction.

  As shown in FIG. 1, the adhesive sheet 1 for processing a brittle member includes a laminated film base material 10 composed of a first film 11 and a second film 12, and adhesive layers 11 a on both outer surfaces thereof. 12a is provided. The pressure-sensitive adhesive layers 11a and 12a are not particularly limited as long as they can be removed again, and conventionally known pressure-sensitive adhesives can be used. For example, it may be a normal weak pressure-sensitive adhesive, or an ultraviolet curable pressure-sensitive adhesive whose peeling force can be controlled by ultraviolet irradiation. The thickness of the pressure-sensitive adhesive layers 11a and 12a is not particularly limited, and is usually about 1 to 300 μm, preferably 5 to 50 μm.

  The pressure-sensitive adhesive layers 11a and 12a provided on both outer surfaces of the laminated film base material 10 may be the same, but may be made of different materials on both sides. In the process to be described later, the first film 11 is separated from the hard plate 3 in a state of being attached to the brittle member 2. In order to facilitate the subsequent removal of the first film 11, the pressure-sensitive adhesive layer 11a is preferably made of a weak pressure-sensitive adhesive or an ultraviolet curable pressure-sensitive adhesive.

  In the present invention, the brittle member 2 may be reinforced by further bonding a protective tape or the like on the brittle member 2.

  In the processing method of the present invention, as described above, the brittle member 2 is fixed on the hard plate 3 via the brittle member processing adhesive sheet 1. The order in this case is not particularly limited, and the brittle member 2 may be pasted on the hard plate 3 on which the brittle member processing pressure-sensitive adhesive sheet 1 has been pasted in advance, or vice versa. When the brittle member 2 is a semiconductor wafer having a circuit formed on the surface, the circuit surface side is bonded to the brittle member processing adhesive sheet 1 to protect the circuit surface.

  Next, an arbitrary treatment is performed on the brittle member 2. This process varies depending on the use of the brittle member 2, and includes various processing processes, conveyance, storage, and the like. For example, in the case where the brittle member 2 is a semiconductor wafer having a circuit formed on the surface, the processing includes etching, polishing, sputtering, vapor deposition, and grinding on the wafer back surface. If the processing applied to the brittle member 2 is storage or transportation, a protective tape or the like is further bonded to the brittle member 2 to reinforce the brittle member 2 prior to such processing. Also good.

  Thereafter, the brittle member 2 is separated from the hard plate 3. At this time, as shown in FIG. 3, the first film 11 is completely cut into substantially the same shape as the outer edge shape of the brittle member 2. The cutting of the first film is performed using a cutter or laser light. Since the airtightness between the first film 11 and the second film 12 at the film end is released by cutting the first film 11, the first film 11 starts from the film end. The second film 12 can be separated.

  The second film 12 may be cut simultaneously with the cutting of the first film 11, but the second film 12 may not be cut. In the case where the second film 12 is not cut, the airtightness between the first film and the second film can be easily released by folding or stretching the end of the second film 12.

  Moreover, the diameter of the hard plate 3 is the same as or slightly larger than the diameter of the brittle member 2 as described above. The inner diameter of the binding portion 13 may be smaller than the diameter of the hard plate 3 as shown in FIG. 1, or may be larger than the diameter of the hard plate 3 as shown in FIG. In the configuration shown in FIG. 4, the first film and the second film are cut simultaneously.

  The airtightness between the 1st film 11 and the 2nd film 12 is cancelled | released by the said process. As a result, the laminate of the brittle member 2 and the first film 11 can be separated from the hard plate 3 as shown in FIG.

  Thereafter, the first film 11 is peeled from the brittle member 2. When the pressure-sensitive adhesive layer 11a is formed of an ultraviolet curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer 11a is irradiated with ultraviolet light before the first film 11 is peeled off from the brittle member 2 so that the adhesive strength is increased. Therefore, peeling of the brittle member 2 is further facilitated.

  In the present invention, a brittle member is fixed to a hard plate for protection through a brittle member processing adhesive sheet having a laminated film base material bonded only at the peripheral edge. Since the brittle member is fixed and protected on the hard plate, the brittle member can be held without being deformed during transportation, storage, and processing of the brittle member. Further, after the required treatment, the brittle member can be easily separated from the hard plate by cutting the laminated film substrate, so that the brittle member can be easily peeled off and the brittle member is prevented from being damaged. .

One process of the processing method of the brittle member of this invention is shown. One process of the processing method of the brittle member of this invention is shown. One process of the processing method of the brittle member of this invention is shown. The modification in one process of the processing method of a brittle member of the present invention is shown. One process of the processing method of the brittle member of this invention is shown. 1 shows a static friction coefficient measuring device.

DESCRIPTION OF SYMBOLS 1 ... Adhesive sheet 10 for brittle member processing ... Laminated film base material 11 ... 1st film 11a ... Adhesive layer 12 ... 2nd film 12a ... Adhesive layer 13 ... Binding part 2 ... brittle member 3 ... hard plate 20 ... static coefficient of friction measuring device 21 ... table 22 ... sliding piece 22a ... felt 23 ... test film 24 ... Test film 25 ... Spring 26 ... Load cell

Claims (2)

A laminated film base material comprising a first film and a second film, the peripheral edges of which are bound together, and two films being tightly and tightly integrated in an inner region surrounded by the binding part When,
A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed on both outer surfaces of the laminated film substrate.   The pressure-sensitive adhesive sheet according to claim 1, wherein the coefficient of static friction between the inner surfaces of the laminated film base material is 0.1 or more.

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