JPH05245967A - Foamed releasable sheet - Google Patents

Abstract

PURPOSE:To obtain an adhesive sheet for processing capable of easily recovering a processed component and capable of obtaining an objective component in good yield without being affected by processing accuracy even when a processing stand or a support base material has unevenness. CONSTITUTION:A foamable releasable sheet is formed by providing two or ore foaming agent-containing adhesive layers 2, 3 on a support base material 1 in such a combination that the treatment temps. of a foaming agent are different. A component to be processed is bonded and held through the foaming agent-containing adhesive layer for high temp. treatment and can be processed in this state while the buffer effect to unevenness difference is developed through the foaming agent-containing adhesive layer for low temp. treatment after heat treatment and, after processing, the objective component can be easily recovered by the reduction of the bonding strength of the foaming agent- containing adhesive layer for high temp. treatment without damaging the part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamed peelable sheet capable of improving a processing yield of electronic parts and the like and easily recovering the processed parts.

[0002]

2. Description of the Related Art There has been proposed a method of fixing or temporarily fixing an electronic component or the like with an adhesive sheet and performing a predetermined process. Examples are polishing of the back surface of a semiconductor wafer on which a circuit pattern is formed, dicing into chips, and chip formation of laminated ceramic green sheets for forming capacitors.

Conventionally, as the above-mentioned adhesive sheet, one in which a pressure-sensitive adhesive layer or a heat-sensitive adhesive layer is provided on a supporting substrate has been known. In addition, there has been proposed a device in which the adhesive force of the adhesive layer can be reduced so that the formed parts can be easily recovered after processing.

However, in any case, there is a problem that irregularities due to scratches, contamination, etc. on the working table and the supporting base material affect the working accuracy and reduce the yield. Attempts have been made to use a cushioning material such as foam for the supporting substrate, but satisfactory results have not been obtained.

[0005]

DISCLOSURE OF THE INVENTION The present invention makes it possible to easily collect processed parts, and even if there are irregularities on the processing table or the supporting base material, the processing accuracy is not affected, and the target parts can be produced with high yield. The subject is to develop an adhesive sheet for processing that can be obtained.

[0006]

SUMMARY OF THE INVENTION The present invention provides a support substrate having
It is intended to provide a foamed peelable sheet characterized in that a foaming agent-containing adhesive layer having at least two layers is provided in a combination having different treating temperatures of a foaming agent.

[0007]

By providing two or more foaming agent-containing adhesive layers having different treatment temperatures, the foaming agent-containing adhesive layer for high temperature treatment is kept in an untreated state while the foaming agent-containing adhesive layer for low temperature treatment is heated. It can be treated to expand or foam the blowing agent. As a result, while holding the component to be processed through the foaming agent-containing adhesive layer for high temperature treatment, it is possible to exert a buffering effect during processing through the foaming agent-containing adhesive layer for low temperature treatment after heat treatment. it can.

In the above, because the expansion (foaming) treatment adapted to the irregularities of the supporting base material is achieved by the heat treatment in the state where the foaming agent-containing adhesive layer for low temperature treatment is attached to the supporting base material, or As a result, a processed surface (adhesive surface) with excellent smoothness is formed, and unlike the conventional specification adhesive sheet that uses foam as a supporting base material, the processing base and supporting base material used have unevenness. However, the processing accuracy is not affected, and the target component can be obtained with high yield. The easy recovery of the formed parts after processing can be achieved by reducing or disappearing the adhesive force due to expansion or foaming of the contained foaming agent by heat treatment of the foaming agent-containing adhesive layer for high temperature treatment.

[0009]

EXAMPLE FIG. 1 illustrates the foam release sheet of the present invention. Reference numeral 1 is a supporting substrate, 2 is a foaming agent-containing adhesive layer for low temperature treatment, and 3 is a foaming agent-containing adhesive layer for high temperature treatment. In the present invention, the foaming agent-containing adhesive layer for low temperature treatment and that for high temperature treatment may be on the same side or opposite sides of the supporting substrate.

Further, it may have three or more foaming agent-containing adhesive layers. In that case, the treating temperature of the foaming agent may be different in each layer, or may be a combination of two kinds of low temperature and high temperature. From the viewpoint of the buffering effect of irregularities in the supporting base material or the like, a structure in which a foaming agent containing adhesive layer for low temperature treatment is provided between the foaming agent containing adhesive layer for high temperature treatment and the supporting base material is preferable.

As the supporting base material, any suitable material such as a plastic film, paper, woven cloth, non-woven cloth or felt, metal foil, foamed material, laminates thereof, etc. may be used, but one having excellent surface smoothness is preferred. .. The thickness is generally 10 μm to 5 mm, but is not limited to this. A foamed peelable sheet may be used in which an adhesive layer can be appropriately transferred by using a separator composed of a thin sheet treated with a release agent as a supporting base material.

An appropriate adhesive can be used to form the foaming agent-containing adhesive layer, and a pressure sensitive adhesive or the like is generally used. As the pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive,
Appropriate ones such as acrylic pressure sensitive adhesives and styrene / conjugated diene block copolymer type pressure sensitive adhesives can be used, and ultraviolet curable ones can also be used (JP-A-56).
No. 61468, JP 61-174857, and JP 63-17981).

[0013] Further, those which contain a heat-melting resin having a melting point of about 200 ° C or less to improve creep properties, and those which have a low adhesive strength at room temperature and exhibit sufficient adhesive strength by heating. A pressure sensitive adhesive or the like can also be used (Japanese Patent Publication No. 56-
13040). The pressure-sensitive adhesive may be a mixture of appropriate additives such as a cross-linking agent, a tackifying resin, a plasticizer, a filler, and an anti-aging agent, if necessary.

More specifically, for example, a rubber-based pressure-sensitive adhesive containing natural rubber or synthetic rubber as a base polymer, methyl group, ethyl group, propyl group, butyl group, 2-ethylhexyl group, isooctyl group, isononyl group, Usually, such as isodecyl group, dodecyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group and eicosyl group, such as acrylic acid or methacrylic acid having an alkyl group having 20 or less carbon atoms, Acrylic acid alkyl ester, acrylic acid, methacrylic acid, itaconic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate,
Acrylic pressure-sensitive adhesive based on an acrylic polymer containing N-methylolacrylamide, acrylonitrile, methacrylonitrile, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, styrene, isoprene, butadiene, isobutylene, vinyl ether, etc. Etc.

In the adhesive layer for adhering the parts to be processed, the balance between the adhesive force (component holding force) before the adhesive force reduction process and the adhesive force reduction property (easiness of component recovery) due to the adhesive force reduction process. The pressure-sensitive adhesive which can be preferably used from the viewpoints such as above has a dynamic elastic modulus of 5 at room temperature to 150 ° C.
0,000 to 10,000,000 dyne / cm ² , preferably 500,000 to 80
The base polymer is a highly elastic polymer in the range of 0,000 dyne / cm ² . Highly elastic polymers that are more preferable as the base polymer have a small rate of change in dynamic elastic modulus from room temperature to 150 ° C.
It is within double.

The foaming agent-containing adhesive layer can be formed by blending a foaming agent with the adhesive. When the pressure sensitive adhesive at the time of heat is used, a foaming agent that expands or foams at a temperature higher than the bonding treatment temperature of the adhesive is used. The blending amount of the foaming agent may be appropriately determined according to the extent to which the adhesive layer is expanded (foamed) and the extent to which the adhesive force is reduced. Generally, 1 to 100 parts by weight, preferably 5 to 50 parts by weight, and especially 10 to 40 parts by weight are blended per 100 parts by weight of the base polymer.

The foaming agent used is not particularly limited,
Various inorganic or organic foaming agents can be selectively used so that at least two kinds of treatment temperatures for low temperature treatment and high temperature treatment are combined. The temperature difference given to the treatment temperature is appropriately determined according to the treatment accuracy such as the temperature-sensitive property of the foaming agent, but is generally 20 to 100 ° C, and especially 30 to 70 ° C.
The difference in processing temperature is.

Examples of commonly used inorganic foaming agents include ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, and azides.

Examples of commonly used organic blowing agents include water, fluorinated alkanes such as trichloromonofluoromethane and dichloromonofluoromethane, azobisisobutyronitrile and azodicarbonamide, and barium azodicarboxylate. Such as azo compounds, paratoluenesulfonyl hydrazide and diphenylsulfone-3,3 '
Hydrazine compounds such as disulfonyl hydrazide, 4,4′-oxybis (benzenesulfonyl hydrazide) and allyl bis (sulfonyl hydrazide), semicarbazide compounds such as ρ-toluylene sulfonyl semicarbazide and 4,4′-oxy bis (benzenesulfonyl semicarbazide) Compounds, triazole-based compounds such as 5-morpholyl-1,2,3,4-thiatriazole, N, N '
Examples thereof include N-nitroso compounds such as -dinitrosopentamethylenetetramine and N, N'-dimethyl-N, N'-dinitrosoterephthalamide.

The heat-expandable fine particles obtained by encapsulating the foaming agent in microcapsules are preferably used because the mixing operation is easy. As the heat-expandable fine particles, there are commercially available products such as Microsphere (trade name, manufactured by Matsumoto Yushi Co., Ltd.). In the present invention, a foaming aid may be added if necessary.

The foam-releasing sheet is formed, for example, by a method of coating and forming an adhesive layer containing a different foaming agent on both sides of a supporting base material, and by forming an adhesive layer containing a foaming agent on one side of the supporting base material. , A method in which an adhesive layer containing a different foaming agent is coated and laminated thereon, and a foaming agent-containing adhesive layer having a predetermined layer structure is transferred by transferring the foaming agent-containing adhesive layer coated and formed on a separator. An appropriate method such as a method of providing may be used.
The thickness of each foaming agent-containing adhesive layer to be provided may be appropriately determined. Generally, the thickness is 500 μm or less, especially 5 to 200 μm. In addition, on the side of the supporting base material to which the processing target component is not adhered, an adhesive layer which does not contain a foaming agent and which is usually pressure-sensitive or the like may be provided as the outermost layer for adhering to the processing table.

The foamed peelable sheet of the present invention is one in which at least two types of foaming agent-containing adhesive layers for low temperature treatment and high temperature treatment are provided on a supporting substrate, and the application thereof is, for example, FIG. 2, FIG. As illustrated in FIG. 2, the foaming agent-containing adhesive layer 3 for high temperature treatment in the foam release sheet arranged on the processing table 5
After the part 4 to be processed is adhered and held, the foaming agent-containing adhesive layer (2) for low-temperature treatment is heat-treated to expand (foam) the foaming agent to form the treatment layer 21, and then the part 4 is used for the purpose. After the processing as described above is performed, the foaming agent-containing adhesive layer (3) for high temperature treatment is heat-treated to expand or foam the foaming agent to form a processing layer 31 having a reduced adhesive force, and the processed part formed It can be performed as a method of collecting 41.

The heating conditions of the foaming agent-containing adhesive layer having different treatment temperatures may be appropriately determined by the foaming temperature of the foaming agent in each layer depending on the heat resistance of the supporting base material used for the foam release sheet. The heat treatment, the adhesion of the component to be processed, and the placement of the foam release sheet on the processing table can be performed at appropriate stages according to the purpose of use.

The foamed peelable sheet of the present invention is preferably used in various applications in which a part to be processed is processed while being adhered and held, and after the processing purpose is achieved, the formed part can be easily separated (separated) and collected. be able to. At that time, a foam peelable sheet may be arranged at regular intervals via a carrier tape so that it can be continuously introduced into an automatic processing line. Therefore, the foam peelable sheet can be used in an appropriate form. Further, the adhesion holding treatment of the component to be processed can be performed by an appropriate method such as a simple pressure treatment or a heat pressure treatment according to the adhesive property of the foaming agent-containing adhesive layer.

The parts to be processed are arbitrary. Examples include electronic components such as semiconductor wafers and chips,
There are various parts such as electric parts such as ceramic capacitors and oscillators, display devices such as liquid crystal cells, and other parts such as thermal heads, solar cells, and printed circuit boards. Further, the processing to be performed is optional, for example, polishing processing, dicing, pattern formation or assembly.

Example 1 100 parts of a base polymer composed of acrylic graft rubber (20 parts of acrylic (weight part, the same applies hereinafter): MMA),
10 parts of terpene-based tackifying resin, 60 parts of high softening point resin having Tg of 180 ° C., 1 part of vulcanizing agent, and heat-expandable fine particles A
(Microsphere F-301D: 100 ° C. for heat foaming, the same below) or heat-expandable fine particles B (Microsphere F-80SD: 150 ° C. for heat foaming, the same below) 50
First, a toluene solution of an adhesive prepared by blending 1 part is prepared, and a polyester film having a thickness of 25 μm is used to apply a content of the heat-expandable fine particles A to one surface of the polyester film so that the thickness after drying is 30 μm. Heat-drying treatment is carried out, and then the heat-expandable fine particles B so that the thickness after drying is 30 μm.
Of the pressure-sensitive adhesive containing no heat-expandable fine particles is applied to the other surface of the polyester film so as to have a thickness after drying of 30 μm, and heat-dried to foam. A peelable sheet was obtained.

Example 2 100 parts of an adhesive consisting of 90 parts of butyl acrylate / 10 parts of acrylonitrile / 5 parts of acrylic acid (adhesion temperature 100
(° C.) Toluene solution containing 50 parts by weight of heat-expandable fine particles A or heat-expandable fine particles B was used, and a foam peelable sheet was obtained according to Example 1.

Comparative Example 1 A foamed peelable sheet was prepared in the same manner as in Example 1 except that a 30 μm thick adhesive layer containing no heat-expandable fine particles A was provided between the polyester film and the adhesive layer containing the heat-expandable fine particles B. Obtained.

Comparative Example 2 According to the same manner as in Example 1 except that an acrylic foam having a thickness of 85 μm (expansion ratio of 2) was used as a supporting substrate, a foam-peelable sheet having no foam layer containing the heat-expandable fine particles A was obtained. It was

Evaluation test Machinability A polyester patch sheet having a diameter of 10 mm and a thickness of 50 μm is placed on an aluminum plate, and the foam release sheets obtained in Examples and Comparative Examples are stuck thereon and heat-treated at a predetermined temperature. After that, the state of bubbles remaining in the peripheral portion of the patch sheet was observed to evaluate the surface roughness absorbability. The criteria for evaluation are: when no air bubbles are observed and the perimeter of the patch sheet is filled without gaps, ○, when gaps are found in some places around the patch sheet due to air bubbles remaining, Δ, When there was a gap due to residual air bubbles in the entire peripheral portion, it was rated as x.

Adhesive Strength A stainless steel plate (SUS) was used for the adhesive layer containing the heat-expandable fine particles B in the foam release sheets obtained in Examples and Comparative Examples.
304 BA finished surface) at room temperature or 100 ° C
(Adhesion treatment), and the adhesive force (180 degree peel) after heat treatment at 150 ° C. for 1 minute is JIS Z 0237.
It was measured according to.

The above results are shown in Table 1. In addition, in the table,
For the adhesive layer containing the heat-expandable fine particles A in the workability test, the layer thickness after heat expansion (A layer thickness) is also shown.

[Table 1]

[0033]

According to the present invention, since two or more foaming agent-containing adhesive layers having different foaming agent treatment temperatures are provided, the parts to be processed are bonded through the foaming agent-containing adhesive layer for high temperature treatment. It is possible to carry out processing while exerting a buffering effect against unevenness difference and the like through the foaming agent-containing adhesive layer for low temperature treatment after heat treatment while holding, and it is excellent in yield of target parts.
Further, after processing, the adhesive force of the foaming agent-containing adhesive layer for high temperature treatment can be reduced, and the target component can be easily recovered without damaging it.

[Brief description of drawings]

FIG. 1 is a sectional view of an example.

FIG. 2 is a sectional view illustrating an application process of the embodiment.

FIG. 3 is a cross-sectional view illustrating another application process of the embodiment.

[Explanation of symbols]

 1: Supporting substrate 2: Foaming agent-containing adhesive layer for low temperature treatment 21: Foaming agent-containing adhesive layer for low temperature treatment after heat treatment 3: Foaming agent-containing adhesive layer for high temperature treatment 31: High temperature treatment after heat treatment Foaming Agent-Containing Adhesive Layer 4: Parts to be Processed 41: Formed Parts 5: Processing Table

Claims (2)

[Claims] 1. A foam-peelable sheet, characterized in that two or more foaming agent-containing adhesive layers are provided on a supporting substrate in a combination having different foaming agent treatment temperatures. 2. The foam peelable sheet according to claim 1, further comprising a foaming agent-containing adhesive layer for low temperature treatment between the foaming agent-containing adhesive layer for high temperature treatment and the supporting substrate.