JP4482862B2 - Adhesive member and wafer processing method - Google Patents

Description

  The present invention relates to an adhesive member and a wafer processing method.

Ultra-thin semiconductor wafers are required due to the demand for miniaturization of electronic equipment, but because ultra-thin wafers are prone to warping and cracking, a support such as a glass plate or metal plate is pasted in the wafer processing process. In order to prevent warping and cracking, the wafers are peeled off from the wafer after processing. Conventionally, a sticking of the wafer and the support, but had the like liquid wax and adhesive tape, which is difficult to paste the wafer in voidless, hardly peeled without breaking the wafer or contamination on the wafer surface tends to remain There was a problem. Further, some gas is generated and peeled off by stimulation, but it is necessary to go through a process of irradiating the wafer with light or the like, and process management becomes difficult.

JP 2003-211871 A Journal of the Adhesion Society of Japan VOL39, 8 p. 295 (2003)

  The present invention uses an adhesive component that gels by stimulation of heat, light, and the like, and a peelable adhesive member having two-dimensional fiber components as essential components, and supports such as ultrathin wafers, glass plates, and metal plates By sticking, the wafer can be easily peeled off.

There has been a demand for an adhesive member that can be attached to a support member with a voidless dress, does not require heat and UV stimulation at the time of peeling, and can be peeled off with almost no deformation of the wafer. In order to achieve the above object, the present invention is configured as follows.
That is, the present invention attaches a wafer and a support member with an adhesive member, gels by stimulation of heat, light, etc., and applies a shear stress between the two-dimensional fiber component and the support member after processing the wafer, The present invention relates to an adhesive member that peels from a support member, and is composed of an adhesive component that gels by stimulation of heat, light, and the like and a two-dimensional fiber composition.

The present invention also relates to the above-mentioned adhesive member, wherein the adhesive component comprises 1 part of a crosslinkable component that crosslinks by stimulation of heat, light, etc. and 0.2 to 20 parts of a non-crosslinkable component.
The present invention also supports the wafer by attaching the wafer and the support member with the above-mentioned adhesive member and gelling it by stimulation of heat, light, etc., and then applying a shear stress between the two-dimensional fiber component and the support member. The present invention relates to a wafer processing method characterized by peeling from a member.

  By using the adhesive member of the present invention, the wafer can be attached to the support member with a voiceless, and the wafer can be fixed by gelling in a short time by stimulation with heat, light or the like. Further, by applying a shear stress between the embedded two-dimensional fiber structure and the support member, the two-dimensional fiber structure cohesively breaks the gel, so that heat, UV, and other stimuli are not applied at the time of peeling. The wafer can be peeled off without being deformed from the support member. By using a two-dimensional fiber structure that is easily deformed, such as a mesh or a knitted fabric, it is possible to easily cause cohesive failure of the gel and easily peel the wafer.

  The present invention comprises an adhesive member composed of an adhesive component that gels by a stimulus such as heat and light, and a two-dimensional fiber component. The adhesive component that gels upon stimulation by heat, light, etc. is preferably a combination of a crosslinkable component and a non-crosslinkable component. There are resins, phenol resins, and the like, and those that are crosslinked by light are preferable in that they can be crosslinked at a low temperature in a short time. As the non-crosslinkable component, various solvents, reactive diluents, plasticizers and the like are preferable.

  The weight ratio of the non-crosslinkable component when the weight of the crosslinkable component is 1 is preferably 0.2 to 20, and more preferably 0.5 to 10. If the non-crosslinkable component is less than 0.2, the strength of the crosslinked adhesive component is too high, which is not preferable in that it is difficult to peel off the wafer. On the other hand, when it exceeds 20, the strength of the cross-linked adhesive component is too low, and the wafer may be peeled off from the support during the polishing step, which is not preferable.

  In the present invention, gelation means that the adhesive component has a three-dimensional cross-linked structure, as described in a practical plastic terminology (published by Plastic Age Co., Ltd.), etc. It says that it has become rigid.

  Examples of the crosslinkable component include a combination of a photopolymerizable unsaturated compound such as an acrylic polyfunctional oligomer or monomer and a photopolymerization initiator.

  Photopolymerizable unsaturated compounds include (meth) acrylic acid, hydroxylethyl (meth) acrylate, hydroxylpropyl (meth) acrylate, methyl (meth) acrylate, butyl (meth) acrylate, glycidyl (meth) acrylate, ethylene Glycol di (meth) acrylate, polypropylene glycol (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, dipentaerythritol hexa (meth) acrylate Is mentioned. Examples of the polyfunctional oligomer or monomer include trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, and the like. In addition, (meth) acrylic acid means either acrylic acid or methacrylic acid, and (meth) shall have the same meaning hereafter.

  As the photopolymerization initiator, a compound having an absorption wavelength in ultraviolet rays of an exposure machine to be used can be used. Specifically, acetophenone, benzophenone, 4,4 bisdimethylaminobenzophenone, benzoin butyl ether, benzoin isobutyl ether, 2-dimethoxy-2-phenylacetophenone, 2,4-diisopropylthioxanthone, methyl benzoyl formate, 3, 3 , 4,4-tetra (t-butylperoxycarbonyl) benzophenone and the like. These are commercially available from Ciba Geigy Corporation under the trade names: Irgacure 651, Irgacure 369, and Irgacure 819. The addition amount of a photoinitiator is 0.01-10 weight part with respect to 100 weight part of photopolymerizable unsaturated compounds.

  As the non-crosslinkable component, various solvents, reactive diluents, plasticizers and the like can be used. The ratio of the crosslinking component to the non-crosslinking component is preferably 1: 1 to 1:10. If there are many crosslinking components, it will become difficult to peel, and if there are many non-crosslinking components, sufficient adhesive force will not be obtained. As the solvent, methyl ethyl ketone, acetone, methyl isobutyl ketone, 2-ethoxyethanol, toluene, butyl cellosolve, methanol, ethanol, 2-methoxyethanol and the like can be used. A high boiling point solvent may be added for the purpose of suppressing odor. Examples of the high boiling point solvent include dimethylacetamide, dimethylformamide, methylpyrrolidone, and cyclohexanone.

  A high molecular weight component or the like may be added to the adhesive member used in the present invention. In order to improve the interfacial bond between different materials, a coupling agent can be blended. Examples of the coupling agent include a silane coupling agent, a titanate coupling agent, and an aluminum coupling agent, and among them, a silane coupling agent is preferable. Furthermore, it is preferable to mix | blend an inorganic filler with the adhesive member used by this invention for the purpose of adjustment of the viscosity of an adhesive member, provision of thixotropic property, etc. Inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, alumina, aluminum nitride, aluminum borate whisker, boron nitride, crystalline silica, non Examples thereof include crystalline silica and antimony oxide.

  The varnish of the adhesive member can be produced using a rough machine, a three-roll or bead mill, or a combination thereof.

  Examples of the two-dimensional fiber component include fabrics and knitted fabrics in which fibers such as fibril fibers and staple fibers are formed into a planar shape by plain weave, twill weave, satin weave, or the like. Moreover, nonwoven fabrics, such as a felt, are mentioned. The film can be kept constant, and it can be easily deformed from the initial state where the angle between the warp and the weft is approximately 90 ° to 60 ° to 120 °. A plain woven fabric (mesh) having many fiber voids is preferable in that the substrate is easily peeled off and the support substrate is easily peeled off, and the adhesive component penetrates the inside of the two-dimensional fiber structure and is easily distributed evenly on the front and back. The thickness of the two-dimensional fiber component is preferably 10 to 200 μm. When the thickness is within this range, the adhesiveness and stress relaxation effect are maintained, and the cost is excellent. The fiber type may be either a fibril fiber or a staple fiber, and fibril fibers such as nylon, polyester, and polyamide are preferred in terms of uniform thickness and high strength. Moreover, the adhesive component which gelatinizes may be a prepreg impregnated with the two-dimensional fiber component, and when the wafer and the support member are attached, the adhesive component which gels with the two-dimensional fiber component is impregnated. Anyway.

As the support, a plate-like inorganic material such as a glass plate, a quartz plate, an alumina ceramic plate,
A metal plate such as an aluminum plate or a stainless steel plate, or a plastic plate such as an acrylic resin or an epoxy resin is used.

  In order to prevent contamination by the adhesive component that gels, an adhesive film may be attached in advance to the surface of the support or wafer. A commercially available BG tape or the like can be used as such an adhesive film.

Hereinafter, although the adhesive member of this invention is concretely demonstrated with an Example and drawing, this invention is not limited to this.

Example 1
A silicon wafer having a diameter of 6 inches and a thickness of 300 μm was prepared as the wafer 4, and a glass plate having a thickness of 5 mm and a 20 cm square was prepared as the support member 1. Adhesive component 3 is a photopolymerizable unsaturated compound dipentaerythritol hexaacrylate 26 parts as a crosslinkable component, a photopolymerization initiator Irgacure 369 (product name, manufactured by Ciba Specialty Chemicals), a non-crosslinkable component A varnish consisting of 100 parts of solvent acetone and 14 parts of a carboxyl group-containing NBR (PSR-1 manufactured by JSR, trade name) as a high molecular weight component was used as an additive. The ratio of the crosslinking component to the non-crosslinking component of this adhesive component is 1: 3.77.

  As the two-dimensional fiber component 2, a nylon mesh (thickness 75 μm, fiber thickness 40 μm, interfiber distance 90 μm) was used.

  As shown in FIG. 1, after placing the two-dimensional fiber structure 2 on the support member 1 and hanging the adhesive component 3 in the center, the wafer 4 was stuck on it as shown in FIG. . 1 and 2, (a) is a schematic cross-sectional view, and (b) is a perspective view or a top view.

In Example 1, since the adhesive component was in a liquid state before UV light irradiation, the wafer and the glass plate could be pasted without mixing voids. In this state, as shown in FIG. 3, ultraviolet rays (irradiation time: 3 seconds, irradiation amount: 500 mJ / cm ^{2 in} I-line intensity) were irradiated to crosslink the adhesive component, and the wafer was fixed. Since the two-dimensional fiber structure 2 serves as a spacer, the thickness of the adhesive component was about 70 μm over the entire surface of the wafer. Furthermore, since the liquid resin was gelled by UV curing, the wafer could be fixed in 3 seconds. In this state, the wafer was polished to a thickness of 50 μm.

  Next, as shown in FIG. 4, a shear stress (100 N) is applied between the glass plates in the direction parallel to the warp of the two-dimensional fiber structure 2 (direction B in FIG. 2). 1 peeled off. The wafer could be peeled without cracks. In some experiments, some transfer of the adhesive member was observed on the surface of the wafer, but these could be easily cleaned by cleaning in acetone.

(Example 2)
Except that a shear stress (100 N) was applied between the glass plates in a direction intersecting with the warp yarn of the two-dimensional fiber structure 2 at an angle of 45 ° (A direction in FIG. 2), and the same was peeled off, the same as in Example 1. .

In addition to being able to attach a wafer and a glass plate in the same manner as in Example 1, a shear stress (100 N) was applied between the glass plates at a 45 ° angle with the warp of the two-dimensional fiber structure 2 as shown in FIG. The angle between the warp and the weft of the two-dimensional fiber structure 2 is changed from about 90 ° to 60 to 120 °, resulting in a fine break point between the adhesive component 3 and the two-dimensional fiber structure 2, and further shearing. When the stress was continuously applied, the wafer could be peeled without cracks.

It is a schematic diagram which shows the state which provided the two-dimensional fiber structure and the adhesive component on the supporting member. It is a schematic diagram which shows the state which provided the two-dimensional fiber structure and the adhesive component on the supporting member, and also provided the wafer on it. It is a cross-sectional schematic diagram which shows a mode that the ultraviolet-ray light was irradiated to the adhesive component. It is a schematic diagram which shows a mode that the two-dimensional fiber structure was pulled in the direction of B in FIG. It is a cross-sectional schematic diagram which shows a mode that it peeled between the two-dimensional fiber structure and the supporting member. It is a cross-sectional schematic diagram which shows a mode that the adhesive component was peeled from the wafer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support member 2 Two-dimensional fiber structure 3 Adhesive component 4 Wafer A Pull direction B in Example 2 Pull direction in Example 1

Claims (3)

The wafer and the support member are attached with an adhesive member, gelled by heat, light, etc., and the wafer is peeled from the support member by applying a shear stress between the two-dimensional fiber component and the support member after processing the wafer. An adhesive member comprising a two-dimensional fiber composition and an adhesive component that gels when stimulated by heat or light.   2. The adhesive member according to claim 1, wherein the adhesive component comprises 1 part of a crosslinkable component that crosslinks by a stimulus such as heat and light and 0.2 to 20 parts of a non-crosslinkable component.   The wafer and the support member are attached with the adhesive member according to claim 1 and gelled by heat, light, or other stimulus, and then a shear stress is applied between the two-dimensional fiber component and the support member, whereby the wafer is fixed. A wafer processing method, comprising peeling from a support member.

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