WO2013180196A1

WO2013180196A1 - Peelable adhesive, adhesive material using same, and processing device

Info

Publication number: WO2013180196A1
Application number: PCT/JP2013/064970
Authority: WO
Inventors: 康太郎荒谷; 博之香川
Original assignee: 日立オムロンターミナルソリューションズ株式会社
Priority date: 2012-05-31
Filing date: 2013-05-30
Publication date: 2013-12-05
Also published as: JP2013249355A; JP5908795B2

Abstract

A peelable adhesive comprising a main chain of liquid crystal polymer having a plurality of liquid crystal mesogenic groups on a side chain, and a cross-linking group for cross-linking main chains, wherein the mesogenic groups receive energy and experience changes between two or more states, exhibiting different adhesive powers in each of the states. These changes in state can be reversibly controlled using the energy. This makes it possible to reversibly control the adhesive power of the peelable adhesive.

Description

Easy-release adhesive, adhesive material using the same, and processing apparatus

The present invention relates to an easily peelable pressure-sensitive adhesive, a pressure-sensitive adhesive material using the same, and a processing apparatus.

Adhesive materials such as adhesive tapes and adhesive sheets are widely used for packaging, pasting, construction equipment, medical, and surface protection of various products including electrical products. For these applications, adhesives with adhesive strength suitable for various applications have been developed, and rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, etc. have been developed. Yes. In addition, adhesives for fixing electronic devices have also appeared as a flow different from these application examples. In this application, peelability is particularly required for adhesives. A dicing tape is a typical example of this. That is, an easily peelable pressure-sensitive adhesive material that is sticky at the time of fixing (processing step) and non-sticky at the time of picking up (peeling step) is required. For this reason, as can be seen in Patent Document 1, an easily peelable adhesive material that becomes non-adhesive by irradiation with ultraviolet rays or the like has been developed. In addition, as can be seen in Patent Document 2, an easily peelable adhesive material that has become non-adhesive using a foaming phenomenon has also been developed. In the case of these two adhesive materials, irreversible control is achieved with only one adhesion control.

Furthermore, as can be seen in Patent Document 3, an easily peelable adhesive material that becomes non-tacky by utilizing the crystallization phenomenon of a side chain crystalline polymer is disclosed. This side chain crystalline polymer is not a liquid crystalline polymer. This adhesive material can be reversibly controlled.

Non-Patent Document 1 describes using a liquid crystal polymer to apply to various uses, but the uses include an optical functional element as a display or light control material, application to an optical recording material, electrorheology. An electrodynamic functional element and a separation transmission functional element as a fluid or a piezoelastomer are described. The liquid crystal polymers described in this document are those in which a mesogen group is present in the main chain of the liquid crystal polymer, a hybrid liquid crystal polymer in which a mesogen group is added to the main chain, and a mesogen in the main chain of the liquid crystal polymer. A side chain type liquid crystal polymer in which groups are bonded as side chains. Non-Patent Document 1 does not describe the use of a change in adhesive force of a liquid crystal polymer and the crosslinking of the liquid crystal polymer.

JP-A-3-12468 Japanese Patent Publication No. 6-79812 Japanese Patent Laid-Open No. 9-249858

As described above, if the adhesive force can be reversibly controlled between two or more states, it can be understood that a new application field of adhesive materials will be developed and various uses will be developed. In this case, the adhesive force is controlled between two or more states, that is, between the processing step and the peeling step. However, when there are other steps such as conveyance, the adhesive force is reversibly between two or more states. Preferably it can be controlled.

If the adhesive force can be reversibly controlled between two or more states and sorted according to the weight of the electronic component during transportation, a new application development can be expected for the adhesive material. Further, if the adhesive force can be controlled reversibly not by heating but by an electric field or light, the processing step, the conveying step, the peeling step, and the like become very simple steps. As described above, the liquid crystal polymer is characterized in that physical properties related to a plurality of viscosities can be changed under various conditions, and an adhesive or an adhesive tape can be provided by appropriately combining them. In addition, it is necessary to crosslink the liquid crystal polymer in order to prevent the pressure sensitive adhesive from moving to an object where it is not preferable to adhere to the product or the like.

An object of the present invention is to provide an easily peelable adhesive capable of reversibly controlling the adhesive force between two or more states, and to provide an adhesive material and a processing apparatus using the easily peelable adhesive. There is.

The novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

The easily peelable pressure-sensitive adhesive of the present invention includes a main chain of a liquid crystal polymer having a plurality of liquid crystalline mesogen groups in the side chain and a cross-linking group that cross-links between the main chains, and the mesogen group receives energy. It causes a change between two or more states and exhibits different adhesive strength in each state. The above change can be reversibly controlled by energy.

According to the present invention, it is possible to reversibly control the adhesive force of an easily peelable adhesive. Moreover, the adhesive material using this easily peelable adhesive can be provided. Furthermore, a processing apparatus capable of reversibly controlling the adhesive force can be provided.

A general formula of a side chain type liquid crystalline polymer having a liquid crystalline mesogen in the side chain and a crosslinking group in the main chain is shown. A general formula of a copolymer liquid crystal polymer having a liquid crystalline mesogen in the side chain and a crosslinking group in the main chain is shown. The general formula of a side chain type mesogen group is shown. The specific example of the molecular structure of the side chain type liquid crystalline polymer used for this invention is shown. The specific example of the molecular structure of the side chain type liquid crystalline polymer used for this invention is shown. Specific examples of the crosslinking group of the side chain type liquid crystalline polymer used in the present invention are shown below. It is a structural formula of the crosslinkable side chain type liquid crystalline polymer used in the present invention. It is a structural formula of another crosslinkable side chain type liquid crystalline polymer used in the present invention. It is a structural formula of another crosslinkable side chain type liquid crystalline polymer used in the present invention. It is a structural formula of another crosslinkable side chain type liquid crystalline polymer used in the present invention. It is a structural formula of the other crosslinkable side chain type liquid crystalline polymer (adhesive precursor) used for this invention. It is a structural formula of the other crosslinkable side chain type liquid crystalline polymer (adhesive precursor) used for this invention. It is a structural formula of the other crosslinkable side chain type liquid crystalline polymer (adhesive precursor) used for this invention. It is a structural formula of the other crosslinkable side chain type liquid crystalline polymer (adhesive precursor) used for this invention. It is a structural formula of the other crosslinkable side chain type liquid crystalline polymer (adhesive precursor) used for this invention. It is explanatory drawing which shows an example of the easily peelable adhesive material which concerns on this invention. It is explanatory drawing which shows the cross section of the electrode structure of the easily peelable adhesive material which concerns on this invention. It is sectional drawing which shows the cross section of the electrode structure of the easily peelable adhesive material which concerns on this invention. FIG. 17 is a cross-sectional view taken along line AA in FIG. It is explanatory drawing which shows the state which fixed the semiconductor wafer to the base with the easily peelable adhesive material in the dicing apparatus which concerns on this invention. It is explanatory drawing of the state which cut | disconnects the wafer in the dicing apparatus which concerns on this invention with a diamond wheel. It is explanatory drawing of the relationship between the wafer chip and the die bond collector in the dicing apparatus which concerns on this invention. It is explanatory drawing which moves the wafer chip in the dicing apparatus which concerns on this invention with a die-bond collector.

Hereinafter, the present invention will be described in detail together with embodiments (examples) with reference to the drawings.

In the present invention, the main chain of the liquid crystal polymer has a plurality of liquid crystalline mesogen groups in the side chain, and the main chain is cross-linked, and the mesogen group undergoes two or more state changes upon receiving external energy. , An easily peelable pressure-sensitive adhesive capable of exhibiting different adhesive strength under each condition and capable of reversibly controlling the change in the state by external energy, and a pressure-sensitive adhesive material and a processing apparatus using the pressure-sensitive adhesive Is to provide. Here, the processing apparatus is an apparatus that performs cutting, polishing, molding, and the like while the article to be processed is adhesively fixed.

Of the inventions disclosed in this application, the outline of typical ones will be described as follows.

(1) In an easily peelable pressure-sensitive adhesive, it is an easily peelable pressure-sensitive adhesive whose adhesive strength can be reversibly controlled between two or more states, and the main chain is composed of a crosslinking group as a main component. An easily peelable pressure-sensitive adhesive containing a cross-linked side chain liquid crystal polymer and a pressure-sensitive adhesive material using the same. The liquid crystalline side chain (mezzogen group) can express two or more different states depending on temperature, electric field, and the like, and exhibits a specific adhesive force depending on each state. The different states can be reversibly controlled.

(2) A pressure-sensitive adhesive material comprising a pressure-sensitive adhesive containing the above side-chain liquid crystal polymer and a support.

(3) An apparatus for processing an article using an easily peelable adhesive material to which the easily peelable adhesive material is applied, wherein the easily peelable adhesive material contains a cross-linked side chain liquid crystal polymer as a main component of the adhesive. Specifically, an easily peelable pressure-sensitive adhesive containing a cross-linked side chain liquid crystal polymer capable of reversibly causing two or more state changes and reversibly controlling adhesiveness, and the easily peelable pressure-sensitive adhesive , A means for changing the state of the easily peelable adhesive material by applying energy from the outside to the easily peelable adhesive material, and a means for transporting the article to be treated to the easily peelable adhesive material Is a processing apparatus.

The state for controlling the adhesive force of the easily peelable pressure-sensitive adhesive according to the present invention means the thermodynamic phase state of the crystal phase, liquid crystal phase, and isotropic liquid phase of the easily peelable pressure-sensitive adhesive material. In the present specification, the “state change” refers to the state change exemplified above. The “state” herein includes a glassy state of a polymer, and also includes a smectic liquid crystal phase, a nematic liquid crystal phase, a cholesteric liquid crystal phase, a discotic liquid crystal phase, and the like that are polymorphs of a liquid crystal phase. In addition to these thermodynamic phase states, for example, an on state and an off state, which are electrically controlled like a nematic liquid crystal phase, are included. If a mesogenic group that changes its optical structure is used, it is possible to control the adhesive force by expressing a state change even by light irradiation. Therefore, the energy includes heat, an electric field, a magnetic field, light (including ultraviolet rays and infrared rays), sound waves, and the like. Among them, heat, electric field, and light are suitable as energy because they can easily cause a change in the state of the mesogenic group of the liquid crystalline polymer.

In the above state change, since the energy state of the easily peelable adhesive changes, the adhesive force changes as a result.

Various liquid crystalline polymers used in the present invention will be described.

1 is a general formula of the side chain type liquid crystal polymer according to the present invention, and Ln has a crosslinking group in the main chain. Formula 2 in FIG. 2 is a side-chain copolymer liquid crystalline polymer, and has a crosslinking group Ln in the main chain.

In the above general formula represents a P and P 'is a unit of the polymer backbone, L _C represents a mesogen group (mesogenic group), S _P is a spacer linking the P and L _C, R is an alkyl side chain and is a crosslinking site for L _N to crosslink the polymer chains. Ln may be bonded to P ′.

In the present invention, the liquid crystalline polymer has a mesogenic group as a side chain and has a crosslinking group in the main chain of the liquid crystalline polymer. When functioning as an adhesive, the main chain of the liquid crystal polymer is crosslinked except for the mesogenic group. It is necessary to do.

The unit P of the polymer main chain of the side chain type liquid crystal polymer according to the present invention is selected from siloxane, acrylate, and methacrylate. In this case, the unit P of the polymer main chain is siloxane and methacrylate.

The mesogenic group of the side chain type liquid crystal polymer according to the present invention is exemplified by Formula 3 in FIG. In Formula 3, R ¹ is selected from F, CN, an alkyl group having 1 to 30 carbon atoms or an alkoxyl group, A ¹ and A ² are each independently selected from a cyclohexane ring or a phenyl ring, and A ³ is a cyclohexane ring. is selected from phenyl ring or a single ^bond, a Z 1, ^{Z 2} are each _{independently, -O-CO -, - COO} -, - CH 2 -CH 2 -, - CH = CH -, - N = N-, Or it is chosen from a single bond. The above cyclohexane ring or phenyl ring may have a substituent in addition to the linking group other than R ¹ , Z ¹ and Z ² . When Z ¹ and Z ² are —CH═CH— and —N═N—, they become a stilbene mesogen group and an azobenzene mesogen group, respectively, which can change phase from a liquid crystal state to a liquid state by light. The force can be controlled.

Spacer S _P output side chain type liquid crystal polymer according to the present invention is an alkyl group having from 1 to 30 carbon atoms, the methylene group may be substituted oxygen, sulfur, an amine.

As the alkyl side chain R according to the present invention, an aliphatic acrylate having an alkyl group having 1 to 30 carbon atoms can be used. Further, it may be a side chain of another spacer S _P and another mesogen group L _C.

In this alkyl side chain R, when the polymer main chain is an acrylate or methacrylate, a cross-linked side chain type liquid crystal polymer can be obtained by using a polyfunctional acrylate instead of a monofunctional aliphatic acrylate. As the polyfunctional acrylate used in this case, aliphatic diacrylates such as 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, and 1,10-decanediol diacrylate can be used. Further, aliphatic dimethacrylates such as ethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,8-octanediol dimethacrylate, and 1,10-decanediol dimethacrylate can be used.

On the other hand, when the polymer main chain is siloxane, a crosslinked side chain type liquid crystal polymer can be obtained by using modified siloxane instead of monofunctional aliphatic acrylate.

As the crosslinking site according to the present invention, acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, or glycidyl methacrylate is used.

As the crosslinking agent according to the present invention, polyisocyanate and epoxy resin are used when the crosslinking site is acrylic acid or methacrylic acid. When the crosslinking site is 2-hydroxyethyl acrylate or hydroxyethyl methacrylate, polyisocyanate or urea resin is used. When the crosslinking site is glycidyl methacrylate, an acid anhydride is used.

FIG. 4A shows an example of the molecular structure formula (formula 4) of the side chain type liquid crystal polymer. FIG. 4B shows an example of the molecular structural formula (formula 5) of the side chain type liquid crystal polymer.

FIG. 5 shows an example of a crosslinking group (formula 6). The OH group of formula 6 contributes to crosslinking. N in the formula is an integer.

6 to 13 show the molecular structure of the cross-linked side chain liquid crystal polymer.

Formula 7 in FIG. 6 and Formula 8 in FIG. 7 are cross-linkable side chains in which the polymer main chain is an acrylate in the general formula 2 and the alkyl side chain R is a polyfunctional acrylate. It is a specific example of a liquid crystal polymer.

Formula 9 in FIG. 8 and Formula 10 in FIG. 9 are side chain type liquid crystal polymers in which the polymer main chain is siloxane in Formula 2, which is a general formula, and a crosslinked side chain type liquid crystal in which the alkyl side chain R is a modified siloxane. It is a specific example of a polymer.

Formula 11 in FIG. 10A and Formula 12 in FIG. 10B are specific examples of a crosslinkable side chain type liquid crystal polymer in which the polymer main chain is an acrylate in Formula 1, which is a general formula.

FIG. 11 to FIG. 13 are specific examples of a crosslinkable side chain type liquid crystal polymer in which the polymer main chain is an acrylate in the general formula (2). That is, Formulas 13 to 15 show the precursor structure of the pressure-sensitive adhesive of the present invention.

As the support 1 constituting the adhesive material shown in FIG. 14 according to the present invention, paper, cloth, plastic film, non-woven fabric, glass, metal foil or the like is used. Further, an undercoat layer may be provided between the pressure-sensitive adhesive 2 constituting the pressure-sensitive adhesive material shown in FIG. The adhesive material here means an adhesive sheet or an adhesive tape.

As an electrode structure for switching the adhesive force of the side chain type liquid crystal polymer constituting the adhesive material according to the present invention, there are two types, a lateral electric field method shown in FIG. 15 and a fringe field method shown in FIG. Can be used.

In FIG. 15, the pressure-sensitive adhesive is 2, the support is 1, and 3 is an electrode. In FIG. 16, the pressure-sensitive adhesive is 2, the support is 1, 3 is an upper electrode, 4 is an upper electrode, 5 is a lower electrode, and 6 is an insulating coating.

FIG. 17 is a cross-sectional view taken along the line AA in FIG. 16, wherein 31 is a first comb electrode, and 32 is a second comb electrode. Reference numeral 7 denotes an electrode interval. The comb electrode is a means for applying energy to the adhesive layer.

Examples of the processing apparatus using the adhesive material according to the present invention include a semiconductor dicing apparatus and an electronic component conveying apparatus.

Hereinafter, a synthesis example of a crosslinkable adhesive material (adhesive precursor) used for an easily peelable adhesive, an example of easily peelable adhesive, and an example of a processing apparatus using the above adhesive will be described.

(Synthesis Example 1)
4.9 g of 4- (6-acryloxyhexyloxy) phenyl-4- (hexyloxy) benzoate, a monomer of side chain type liquid crystal polymer (Synton Chemical), 0.1 g of hydroxylethyl acrylate as a crosslinking monomer (Kanto Chemical) , And 0.05 g (manufactured by Tokyo Chemical Industry Co., Ltd.) of 2,2-azobisisobutyronitrile, a thermal photopolymerization initiator, were placed in a 50 cc round bottom flask, and 20 cc of toluene was added. The flask was heated to 80 ° C., and the monomer and initiator were dissolved, followed by stirring for 6 hours. After returning to room temperature and reprecipitation with methanol, the product was filtered off and dried at room temperature. From the measurement by GPC, the obtained liquid crystal polymer (crosslinkable adhesive material) had a weight average molecular weight of 42,000. From the thermal analysis and polarization microscope observation, a glass transition point was observed at 20 ° C., a smectic liquid crystal phase-nematic liquid crystal phase transition point at 75 ° C., and a clearing point at 125 ° C. The structure of the obtained pressure-sensitive adhesive precursor is Formula 12.

(Synthesis Example 2)
4.0 g of 4- (6-acryloxyhexyloxy) phenyl-4- (hexyloxy) benzoate as a monomer of a side chain type liquid crystal polymer (Synton Chemical), 0.5 g of methyl acrylate (Kanto Chemical) as an acrylic chain monomer, Hydroxyethyl acrylate 0.1 g (Kanto Chemical) as a cross-linking part monomer and thermal photopolymerization initiator 2,2-azobisisobutyronitrile 0.05 g (manufactured by Tokyo Chemical Industry) were placed in a 50 cc round bottom flask, 20 cc of toluene was added. The flask was heated to 80 ° C., and the monomer and initiator were dissolved, followed by stirring for 6 hours. After returning to room temperature and reprecipitation with methanol, the product was filtered off and dried at room temperature. From the measurement by GPC, the obtained liquid crystal polymer (crosslinkable adhesive material) had a weight average molecular weight of 28,000. From the thermal analysis and polarization microscope observation, a glass transition point was observed at 0 ° C., a smectic liquid crystal phase-nematic liquid crystal phase transition point at 75 ° C., and a clearing point at 125 ° C. The obtained pressure-sensitive adhesive precursor is represented by Formula 14.

(Synthesis Example 3)
4.9 g of 6- (4-cyanobiphenyliloyloxy) hexyl acrylate as a monomer of a side chain type liquid crystal polymer (Synthon Chemical), 0.1 g of hydroxylethyl acrylate as a cross-linking monomer (Kanto Chemical), and a thermal photopolymerization initiator 2,2-azobisisobutyronitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in a 50 cc round bottom flask, and 20 cc of toluene was added. The flask was heated to 80 ° C., and the monomer and initiator were dissolved, followed by stirring for 6 hours. After returning to room temperature and reprecipitation with methanol, the product was filtered off and dried at room temperature. From the measurement by GPC, the obtained liquid crystal polymer had a weight average molecular weight of 31,000. From the thermal analysis and polarization microscope observation, a glass transition point was observed at 20 ° C., a smectic liquid crystal phase-nematic liquid crystal phase transition point at 120 ° C., and a clearing point at 125 ° C. The obtained pressure-sensitive adhesive precursor is represented by Formula 11.

(Synthesis Example 4)
4.95 g of 4- (6-acryloxyhexyloxy) phenyl-4- (hexyloxy) benzoate (Synthon Chemical) which is a monomer of side chain type liquid crystal polymer, 1,6-hexanediol diacrylate which is a polyfunctional acrylate Was added to a 50 cc round bottom flask, and 5 cc of toluene was added to 0.05 g (manufactured by Tokyo Chemical Industry) and 0.05 g of 2,2-azobisisobutyronitrile (manufactured by Tokyo Chemical Industry) as a thermal photopolymerization initiator. The flask was heated to 80 ° C., and the monomer and initiator were dissolved, followed by stirring for 6 hours. It returned to room temperature and produced the cast film | membrane with Teflon (trademark). From the thermal analysis and polarization microscope observation, a glass transition point was observed at 10 ° C., a smectic liquid crystal phase-nematic liquid crystal phase transition point at 50 ° C., and a clearing point at 125 ° C. The cast membrane was immersed in toluene and dried, and the gelation rate of the copolymer was 50% from the weight measurement of the residual film.

Example 1
0.9 g of the side chain type liquid crystal polymer obtained in Synthesis Example 1 and 0.1 g of diphenylmethane-4,4′-diisocyanate (Tokyo Kasei) were dissolved in 10 cc of tetrahydrofuran (Wako Pure Chemical Industries). This solution was applied onto a glass substrate having a thickness of 1 mm and a size of 1 cm × 1 cm, and heated to 100 ° C. to obtain an adhesive sheet. The adhesive strength of this adhesive sheet was evaluated using a force gauge. A sample of the adhesive sheet was placed on a hot plate, and a round metallic attachment was attached to the force gauge side for evaluation. The pressure-sensitive adhesive force at the time of pulling was changed from 0.000 N to 0.004 N by heating from 10 ° C. to 30 ° C., and it was confirmed that the pressure-sensitive adhesive sheet can control the pressure-sensitive adhesive force by a heating operation. Moreover, it became 0.004N to 0.000N by cooling from 30 degreeC to 10 degreeC, and has confirmed that it was an adhesive sheet which can control adhesive force by cooling operation.

In other words, it can be in a state where it can be adhered by a heating operation and can be detached by a cooling operation. That is, a reversible change (state change) can be caused between two states (two temperatures) by a heating operation and a cooling operation. In this embodiment, the control is based on thermal energy.

(Example 2)
0.9 g of the side chain type liquid crystal polymer obtained in Synthesis Example 1 and 0.1 g of diphenylmethane-4,4′-diisocyanate (Tokyo Kasei) were dissolved in 10 cc of tetrahydrofuran (Wako Pure Chemical Industries). This solution was applied onto a glass substrate having a thickness of 1 mm and a size of 1 cm × 1 cm, and heated to 100 ° C. to obtain an adhesive sheet. The adhesive strength of this adhesive sheet was evaluated using a force gauge. A sample of the adhesive sheet was placed on a hot plate, and a round metallic attachment was attached to the force gauge side for evaluation. Adhesive strength at the time of pulling up at 70 ° C. and 90 ° C. was 0.04 N and 0.2 N, respectively, and it was confirmed that the adhesive sheet was able to control the adhesive strength by heating operation. Moreover, it became 0.24 to 0.04N by cooling from 90 degreeC to 70 degreeC, and has confirmed that it was an adhesive sheet which can control adhesive force by cooling operation. This embodiment is also control by heat energy.

(Example 3)
0.9 g of the side chain type liquid crystal polymer obtained in Synthesis Example 1 and 0.1 g of diphenylmethane-4,4′-diisocyanate (Tokyo Kasei) were dissolved in 10 cc of tetrahydrofuran (Wako Pure Chemical Industries). This solution was applied onto a glass substrate having a thickness of 1 mm and a size of 1 cm × 1 cm, and heated to 100 ° C. to obtain an adhesive sheet. The adhesive strength of this adhesive sheet was evaluated using a force gauge. A sample of the adhesive sheet was placed on a hot plate, and a round metal attachment was attached to the force gauge side for evaluation. Adhesive strength at the time of pulling up at 120 ° C. and 140 ° C. was 0.2 N and 0.4 N, respectively, and it was confirmed that the adhesive sheet can control the adhesive strength by a heating operation. Moreover, it became 0.4N to 0.2N by cooling from 140 degreeC to 120 degreeC, and has confirmed that it was an adhesive sheet which can control adhesive force by cooling operation. This embodiment is also control by heat energy.

(Example 4)
0.9 g of the side chain type liquid crystal polymer obtained in Synthesis Example 2 and 0.1 g of diphenylmethane-4,4′-diisocyanate (Tokyo Kasei) were dissolved in 10 cc of tetrahydrofuran (Wako Pure Chemical Industries). This solution was applied onto a glass substrate having a thickness of 1 mm and a size of 1 cm × 1 cm, and heated to 100 ° C. to obtain an adhesive sheet. The adhesive strength of this adhesive sheet was evaluated using a force gauge. A sample of the adhesive sheet was placed on a cool plate, and a round metal attachment was attached to the force gauge side for evaluation. The adhesive strengths when pulled up at −10 ° C. and 10 ° C. were 0.00N and 0.04 N, respectively, and it was confirmed that the adhesive sheet was able to control the adhesive strength by a heating operation. Further, the pressure was changed from 0.04 N to 0.00 N by cooling from 10 ° C. to −10 ° C., and it was confirmed that the pressure-sensitive adhesive sheet can control the adhesive force by the cooling operation. This embodiment is also control by heat energy.

(Example 5)
The side chain type liquid crystal polymer solution obtained in Synthesis Example 4 was applied onto a glass substrate having a thickness of 1 mm and a size of 1 cm × 1 cm, and heated to 100 ° C. to obtain an adhesive sheet. The adhesive strength of this adhesive sheet was evaluated using a force gauge. A sample of the adhesive sheet was placed on a hot plate, and a round metal attachment was attached to the force gauge side for evaluation. The adhesive strength at the time of pulling up at 40 ° C. and 60 ° C. was 0.04 N and 0.2 N, respectively, and it was confirmed that the adhesive sheet can control the adhesive strength by a heating operation. Moreover, it became 0.24 to 0.04N by cooling from 60 degreeC to 40 degreeC, and has confirmed that it was an adhesive sheet which can control adhesive force by cooling operation. This embodiment is also control by heat energy.

(Example 6)
The side chain type liquid crystal polymer obtained in Synthesis Example 4 was placed on a glass substrate having a thickness of 1 mm and a size of 1 cm × 1 cm, and heated to 100 ° C. to obtain an adhesive sheet. The adhesive strength of this adhesive sheet was evaluated using a force gauge. A sample of the adhesive sheet was placed on a hot plate, and a round metal attachment was attached to the force gauge side for evaluation. The adhesive strength at the time of pulling up at 110 ° C. and 130 ° C. was 0.2 N and 0.35 N, respectively, and it was confirmed that the adhesive sheet can control the adhesive strength by a heating operation. Moreover, it became 0.3N from 0.25 by cooling from 130 degreeC to 110 degreeC, and it has confirmed that it was an adhesive sheet which can control adhesive force by cooling operation. This embodiment is also control by heat energy.

(Example 7)
4.5 g of the side chain type liquid crystal polymer obtained in Synthesis Example 1 and 0.5 g of the side chain type liquid crystal polymer obtained in Example 3 were mixed with 0.05 g of diphenylmethane-4,4′-diisocyanate (Tokyo Kasei) and tetrahydrofuran. (Wako Pure Chemicals) 10 cc was dissolved. This solution was applied onto a glass substrate having a thickness of 1 mm and a size of 1 cm × 1 cm, and heated to 100 ° C. to obtain an adhesive sheet.
As shown in FIG. 17, the electrode interval between the first comb electrode and the second comb electrode was 10 μm. The adhesive strength of this adhesive sheet was evaluated using a force gauge. A sample of the adhesive sheet was placed on a hot plate, and a round metallic attachment was attached to the force gauge side for evaluation. While the adhesive strength at the time of pulling up at 90 ° C. was 0.04 N, it was 0.001 N or less by operation when an electric field of 20 V was applied, and it was confirmed that the adhesive sheet can control the adhesive strength by the electric field. It was also confirmed that when the electric field was cut, the adhesive strength recovered to 0.04N. In this embodiment, the control is based on the energy of the electric field.

(Example 8)
4.5 g of the side chain type liquid crystal polymer obtained in Synthesis Example 1 and 0.5 g of the side chain type liquid crystal polymer obtained in Example 3 were mixed with 0.05 g of diphenylmethane-4,4′-diisocyanate (Tokyo Kasei) and tetrahydrofuran. (Wako Pure Chemicals) 10 cc was dissolved. This solution was applied onto a glass substrate having a thickness of 1 mm and a size of 1 cm × 1 cm, and heated to 100 ° C. to obtain an adhesive sheet.
As shown in FIG. 17, the electrode interval between the first comb electrode and the second comb electrode was 10 μm. The adhesive strength of this adhesive sheet was evaluated using a force gauge. A sample of the adhesive sheet was placed on a hot plate, and a round metallic attachment was attached to the force gauge side for evaluation. While the adhesive strength at the time of pulling up at 50 ° C. was 0.01 N, it was 0.001 N or less by operation when an electric field of 100 V was applied, and it was confirmed that the adhesive sheet can control the adhesive strength by the electric field. Further, it was confirmed that the adhesive strength recovered to 0.01 N when the electric field was cut. This embodiment is also control by electric field energy.

Example 9
A dicing apparatus is shown below as an example of an adhesive apparatus (processing apparatus) using an easily peelable adhesive. In this embodiment, the control is based on thermal energy.

The pressure-sensitive adhesive sheet 8 produced using the copolymerizable side chain type liquid crystal polymer obtained in Example 1 was placed on a pedestal 9 of a dicing apparatus as shown in FIG. 18A, and a conveying unit (not shown). ), The wafer 10 is adhesively fixed by being heated to 90 ° C. by the heating means 14.

As shown in FIG. 18B, the wafer 10 is cut using the diamond wheel 11 while the wafer 10 is fixed. Due to the adhesive force of the adhesive sheet, the fixed wafer 10 is not displaced by cutting, and the cut pieces are not scattered.

Thereafter, the pedestal 9 is cooled to 30 ° C. by the cooling means 15 and transferred to the place where the die bond collet 12 (separation part) shown in FIG. 18C is installed. Although the adhesive strength was lowered by lowering to 30 ° C., sufficient adhesive strength was secured for fixing the wafer chip 13 during the transfer operation.

Finally, as shown in FIG. 18D, the base 9 and the adhesive sheet 8 are cooled to 15 ° C. by the cooling means 15 and the wafer chip 13 cut by the die bond collet 12 is taken out.

At this temperature, there was almost no adhesive force of the adhesive sheet, and the wafer chip 13 could be taken up sufficiently by the suction operation with the die bond collet 12. Moreover, since the adhesive of the adhesive sheet 8 was crosslinked except for the liquid crystalline mesogen, it did not adhere to a pedestal, collet, wafer or the like.

Note that the heating means 14 and the cooling means 15 can be collectively referred to as an “energy applying unit”.

Examples of the adhesive device using the adhesive material according to the present invention include a semiconductor dicing device and an electronic component conveying device, but if electric field control can be performed instead of heating control, not only the manufacturing cost of the manufacturing device but also the running cost can be reduced. Reduction can also be achieved. Moreover, since the adhesive force can be controlled between two or more states, various application developments can be expected for the adhesive or adhesive material of the present invention.

The present invention has been specifically described above based on the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Of course.

Hereinafter, the effects of the present invention will be further described.

The liquid crystal polymer generally has heat resistance, and its state change is possible up to a temperature range of about 300 ° C., so the selection range of conditions is wide. In the case of a liquid crystal polymer, not only a change in state due to heat but also control by an electric field is possible, so that a wider range of applications can be developed.

In the present invention, the main chain of the liquid crystal polymer is not cross-linked to change the state, but a plurality of mesogen group groups bonded to the main chain are crystallized by receiving external energy such as heat and electric field. Or from a nematic liquid crystal state to an isotropic liquid state. Therefore, the adhesive force varies depending on the state of the mesogen group, but the liquid crystal polymer itself does not move to the object to be treated. Therefore, the object to be processed and the surroundings are not contaminated.

DESCRIPTION OF SYMBOLS 1 ... Support body, 2 ... Adhesive agent, 3 ... Comb electrode, 31 ... First comb electrode, 32 ... Second comb electrode, 4 ... Upper electrode, 5 ... Lower electrode, 6 ... Insulating film, 7 ... Electrode Interval: 8 ... Adhesive sheet 9 ... Pedestal 10 ... Wafer 11 ... Diamond wheel 12 ... Die bond collet 13 ... Wafer chip 14 ... Heating means 15 ... Cooling means

Claims

A main chain of a liquid crystal polymer having a plurality of liquid crystalline mesogen groups in a side chain, and a cross-linking group that cross-links between the main chains, wherein the mesogen group receives energy between two or more states. An easily peelable pressure-sensitive adhesive that causes a change and exhibits different adhesive strength in each state, and the change can be reversibly controlled by the energy.
The easily peelable pressure-sensitive adhesive according to claim 1, wherein the energy is thermal energy, electric field energy or light energy.
The easily peelable pressure-sensitive adhesive according to claim 1, comprising one or more side chain type liquid crystal polymers represented by monomer units of the following general formula 1.

(In the above general formula 1, P represents a unit of the polymer backbone, L C represents a mesogen group, S P represents the spacer connecting the P and L C, Ln is a linking group between the main chain Crosslink.)
The easily peelable pressure-sensitive adhesive according to claim 1, comprising at least one type of side-chain copolymerizable liquid crystal polymer represented by a monomer unit of the following formula 2.

(In the above formula 2 represents P and P 'is a unit of the polymer backbone, L C represents a mesogen group, S P is a spacer linking the P and L C, R is from 1 to 30 carbon atoms (It is an alkyl side chain, Ln is a bridging group and bridges between main chains, and Ln may be bonded to P ′.)
5. The easy peelability according to claim 1, wherein the repeating unit P of the polymer main chain of the side chain type liquid crystal polymer is one or more selected from the group consisting of siloxane, acrylate and methacrylate. Adhesive.
Spacer S P output side chain type liquid crystal polymer is easily removable pressure sensitive adhesive according to any one of claims 1 to 4, characterized in that an alkyl group having 1 to 30 carbon atoms.
5. The easily peelable pressure-sensitive adhesive according to claim 1, wherein the mesogenic group of the side chain type liquid crystal polymer is represented by the following formula 3.

(In the above formula 3, R 1 is selected from F, CN, and an alkyl group or alkoxyl group having 1 to 30 carbon atoms, A 1 and A 2 are each independently selected from a cyclohexane ring and a phenyl ring, and A 3 is cyclohexane ring is selected from phenyl ring and single bonds, the Z 1, Z 2 are each independently, -O-CO -, - COO -, - CH 2 -CH 2 -, - CH = CH -, - N = N- and a single bond.)
A pressure-sensitive adhesive material having a support and an easily peelable pressure-sensitive adhesive carried on the support, wherein the easily peelable pressure-sensitive adhesive is the one described in any one of claims 1 to 7. Adhesive material to do.
The pressure-sensitive adhesive material according to claim 8, wherein the easily peelable pressure-sensitive adhesive contains a side-chain liquid crystal polymer, and an electrode for switching the side-chain liquid crystal polymer is provided.
A main chain of a liquid crystal polymer having a plurality of liquid crystalline mesogen groups in the side chain, an easily peelable pressure-sensitive adhesive containing a cross-linking group that crosslinks between the main chains, and a member carrying the easily peelable adhesive, An energy applying unit that applies energy to the easily peelable adhesive to change the state of the easily peelable adhesive, a transport unit that transports an article to be processed so as to contact the easily peelable adhesive, and A separation part for separating the article to be treated from the easily peelable adhesive, and the mesogen group receives energy to cause a change between two or more states, and has a different adhesive force in each state. The processing apparatus is characterized in that the change can be reversibly controlled by the energy.