JP2012036269A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for temporary bonding that can be inhibited from being curled during exposure to a high temperature, exhibits excellent heat resistance and is easily removed.SOLUTION: The adhesive composition is an adhesive composition for temporarily bonding an object to an object to be adhered. A film formed from the adhesive composition has a softening point in a range of not less than 100°C to not more than 200°C. The adhesive composition includes a resin and a crosslinking agent. The resin has a functional group exhibiting reactivity with the crosslinking agent and the crosslinking agent reacting with the functional group to produce intermolecular crosslinking in the resin is contained in a range of more than 0 wt.% to less than 50 wt.% based on the weight of the resin.

Description

  The present invention relates to an adhesive composition for temporary fixing. More particularly, the present invention relates to an adhesive composition for temporarily fixing a support substrate or a protective substrate to a product being manufactured in a process involving high temperature treatment.

  In recent years, with the enhancement of functions of mobile phones, digital AV devices, IC cards, and the like, there is an increasing demand for downsizing, thinning, and high integration of semiconductor silicon chips (hereinafter referred to as chips). Further, there is a demand for thinning integrated circuits represented by CSP (chip size package) and MCP (multi-chip package) that integrate a plurality of chips into one package. In order to meet the need for thinner products, it is necessary to thin the chip to 150 μm or less. Further, it is necessary to thin the chip to 100 μm or less for CSP and MCP and 50 μm or less for IC card. Here, a system-in-package (SiP) in which a plurality of semiconductor chips are mounted in one semiconductor package reduces the size of the mounted chip, makes it thinner, and achieves higher integration, thereby improving the performance of electronic devices. This is a very important technology for realizing reduction in size, size and weight.

  Conventionally, a method of connecting bumps (electrodes) for each stacked chip and a circuit board by wire bonding technology is used for SiP products. In order to meet such demands for thinning and high integration, not only wire bonding technology but also through electrode technology in which chips with through electrodes are stacked and bumps are formed on the back surface of the chip are required. is there.

  A thin chip is obtained by, for example, slicing a high-purity silicon single crystal or the like into a wafer, etching a predetermined circuit pattern such as an IC on the surface of the wafer, and incorporating an integrated circuit. Is manufactured by dicing the semiconductor wafer after grinding to a predetermined thickness. At this time, the predetermined thickness is about 100 to 600 μm. Furthermore, the chip for forming the through electrode is ground to a thickness of about 50 to 100 μm.

  In the manufacture of semiconductor chips, the semiconductor wafer itself is thin and fragile, and the circuit pattern has irregularities. Therefore, it is easily damaged when an external force is applied during conveyance to the grinding process or dicing process. Further, in the grinding process, for the purpose of removing the generated polishing debris or releasing the heat generated during polishing, grinding is performed while flowing purified water to the back surface of the semiconductor wafer. At this time, it is necessary to prevent the circuit pattern surface from being contaminated by purified water used for cleaning or the like. Therefore, in order to protect the circuit pattern surface of the semiconductor wafer and prevent damage to the semiconductor wafer, a grinding operation is performed after a processing adhesive film is attached to the circuit pattern surface.

  In addition to the example described above, processes involving a high temperature process in backside wiring such as formation of through electrodes are performed in a state where the semiconductor wafer is bonded and fixed. Many adhesive compositions containing a resin having a high glass transition temperature (Tg) have been proposed as adhesive compositions that can be suitably used in processes involving high-temperature processes, from the viewpoint of excellent heat resistance. .

  However, when the adhesive composition containing a resin having a high Tg is exposed to a high temperature, the film or substrate that protects the circuit pattern surface may be warped. For this reason, if such an adhesive composition is used, it may cause troubles in the transportation of the product or damage the product during the transportation, and thus the product may not be sufficiently protected.

  Therefore, in order to protect the product more appropriately, an adhesive composition containing a resin having a low Tg may be used to temporarily bond a protective film or substrate to a semiconductor wafer or the like in the manufacturing process. It is done.

JP-A-8-165460 (released on June 25, 1996)

  However, since a film formed of an adhesive composition containing a resin having a low Tg has a low softening point, it partially exhibits fluidity when exposed to a high temperature of, for example, 150 ° C. or higher. For this reason, the film formed by such an adhesive composition sinks during a high-temperature process or oozes out from an end portion, so that the object to be bonded cannot be appropriately bonded and fixed to the object. . That is, such an adhesive composition is inferior in heat resistance.

  Here, the adhesive composition for the purpose of protection during the production of the product is required to have a strong adhesive property in a process in which the product is desired to be protected, while being required to have a property that can be easily removed if it is not necessary. However, an adhesive composition for temporary fixing that can suppress warpage during high-temperature exposure, exhibits excellent heat resistance, and is easy to remove has not been proposed so far.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an adhesive composition for temporary fixing that can suppress warpage during high-temperature exposure, exhibits excellent heat resistance, and is easy to remove. It is to provide.

The adhesive composition of the present invention is an adhesive composition for temporarily adhering an object to an object,
The softening point of the film formed from the adhesive composition is in the range of 100 ° C. or higher and 200 ° C. or lower,
Contains a resin and a crosslinking agent,
The resin has a functional group reactive to the cross-linking agent;
The cross-linking agent that reacts with the functional group to cause intermolecular cross-linking in the resin is included in a range of more than 0 wt% and less than 50 wt% with respect to the weight of the resin.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition for temporary fixing which can suppress the curvature at the time of high temperature exposure, shows the outstanding heat resistance, and is easy to remove by the above structures can be provided.

[Adhesive composition]
One embodiment of the adhesive composition according to the present invention will be described below.

The adhesive composition of the present invention is an adhesive composition for temporarily adhering an object to an object,
The softening point of the film formed from the adhesive composition is in the range of 100 ° C. or higher and 200 ° C. or lower,
Contains a resin and a crosslinking agent,
The resin has a functional group reactive to the cross-linking agent;
The cross-linking agent that reacts with the functional group to cause intermolecular cross-linking in the resin is included in a range of more than 0 wt% and less than 50 wt% with respect to the weight of the resin.

  As long as the adhesive composition of the present invention is used as an adhesive for temporarily fixing an object to an object, a specific application is not particularly limited. In the present embodiment, an application of temporarily bonding a semiconductor wafer (object) to a support plate (object) using the adhesive composition of the present invention for a wafer support system is taken as an example. I will explain.

<Resin contained in the adhesive composition>
As described above, the adhesive composition according to the present invention essentially contains a crosslinking agent and a resin containing a functional group that is reactive with the crosslinking agent. The crosslinking agent reacts with the functional group to cause crosslinking between the resin molecules. Moreover, the said adhesive composition can contain the inert resin which does not show the reactivity to the said crosslinking agent as needed. Hereinafter, in accordance with the presence or absence of reactivity to the cross-linking agent, the resin essential for the adhesive resin is described as “active resin”, and any resin for the adhesive resin is described as “inactive resin”.

(Active resin)
The active resin according to the present invention contains a functional group that reacts with a crosslinking agent to form an intermolecular crosslink. Therefore, since the said active resin is contained in the adhesive composition with the said crosslinking agent as mentioned above, it exists in the state bridge | crosslinked in the adhesive composition. For this reason, the said active resin suppresses the sinking of the adhesive composition in a high temperature process. The active resin is partially crosslinked in the adhesive composition. Therefore, the film | membrane formed with the adhesive composition which concerns on this invention can be easily removed from a semiconductor wafer using stripping solution.

  The functional group is an arbitrary functional group that reacts with a cross-linking agent to form cross-links between molecules, and is appropriately selected according to the type of cross-linking agent to be used. Examples of the functional group include vinyl group, (meth) acryloyl group, hydroxyl group and carboxyl group. When preparing an adhesive composition by dissolving an active resin in a solvent together with an inert resin described later, it is preferable to select a functional group having a low polarity so that compatibility with the inert resin can be maintained.

  A plurality of the functional groups are contained in one molecule of the active resin, preferably two. If two functional groups are contained in one molecule of the active resin, moderate partial cross-linking between the active resins can be more reliably formed by adjusting the addition amount of the cross-linking agent. Therefore, sinking of the film of the adhesive composition during high temperature exposure is more appropriately suppressed, and the removal of the adhesive composition from the semiconductor wafer is further facilitated.

  Examples of the active resin having a plurality of functional groups in one molecule of the active resin include polydiene polyol, polycarbonate polyol, polyester polyol, and polyether polyol.

  Examples of the polydiene polyol include polybutadiene polyol and polyisoprene polyol. Hydrogenated polydiene polyols such as hydrogenated polybutadiene polyol and hydrogenated polyisoprene polyol can be used as the polydiene polyol. Examples of polybutadiene polyols include hydroxyl-terminated liquid polybutadiene poly bd R-45HT, R-15HT (made by Idemitsu Kosan Co., Ltd.), hydroxyl-terminated polybutadiene hydride polytail H, polytail HA (made by Mitsubishi Chemical Corp.) mainly having 1,4-bonds. , Terminal hydroxylated polybutadiene G-1000, G-2000, G-3000 (manufactured by Nippon Soda Co., Ltd.) mainly having 1,2-bond, hydride GI of terminal hydroxylated polybutadiene resin mainly having 1,2-bond -1000, GI-2000, GI-3000 (manufactured by Nippon Soda Co., Ltd.) and the like. Examples of polyisoprene polyols include hydroxyl-terminated liquid isoprene Poly ip, Epol (made by Idemitsu Kosan Co., Ltd.), and the like.

  Examples of the polycarbonate polyol include polycarbonate polyols containing repeating units derived from one or more diols selected from polyols such as linear aliphatic diols, alicyclic diols, and glycerin. Examples of the linear aliphatic diol include 1,6-hexanediol, 1,5-pentanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2- And methyl-1,8-octanediol. Examples of the alicyclic diol include 1,4-cyclohexanedimethanol.

  Examples of the polyester polyol include adipate-based polyols such as polyethylene adipate polyol and polybutylene adipate polyol, terephthalic acid-based polyol, and polycaprolactone polyol.

  Examples of the polyether polyol include polypropylene glycol, polytetramethylene ether glycol, and polyvinyl ether polyol. Examples of the polyvinyl ether polyol include TOE-2000H (manufactured by Kyowa Hakko Chemical Co., Ltd.).

  The functional group can be present at any position in the active resin. For example, the functional group is bonded to the main chain or side chain of the active resin. The functional group is preferably located at the end of the molecular chain of the active resin. As a result, the number of functional groups contained in one molecule of the active resin is limited to two, and the degree of crosslinking of the active resin can be within an appropriate range. Examples of the active resin having the functional group at the end of the molecular chain include α, ω-polybutadiene glycol and α, ω-polybutadiene dicarboxylic acid, and hydrides thereof.

  The active resin is a commercially available resin or a resin into which the functional group is introduced after polymerization. For example, the active resin can be obtained by mixing a polymerized resin with a monomer or oligomer having the functional group and a peroxide, and kneading and reacting with a melt twin screw extruder.

  When the adhesive resin further contains an inactive resin described later, the active resin is in the range of 10 parts by mass or more and 20 parts by mass or less when the total of the active resin and the inactive resin is 100 parts by mass. It is preferable that it is contained. When the content of the active resin in the adhesive composition is within the above range, the amount of the active resin that is included in the adhesive composition and forms a cross-link between molecules can be within an appropriate range. . Therefore, it is possible to more reliably realize the suppression of warpage, the improvement of heat resistance, and the maintenance of solubility in the stripping solution.

(Inert resin)
The adhesive composition according to the present invention may further include an inert resin that does not react with the above-described crosslinking agent. The inert resin is selected from any resin that improves or does not impair any of the properties exhibited by the adhesive composition according to the present invention, such as warpage suppression, heat resistance or solubility in a stripping solution.

  From the viewpoint that the warpage of the adhesive composition during high temperature exposure can be further suppressed, the inert resin preferably contains a thermoplastic elastomer. The thermoplastic elastomer is preferably a polymer having a glass transition temperature of 30 ° C. or lower (for example, a thermoplastic elastomer having a glass transition temperature of room temperature or lower). An elastomer having such a glass transition temperature is preferable because warpage of the adhesive composition can be more reliably suppressed.

  Examples of thermoplastic elastomers include isoprene rubber and hydrogenated products thereof; chloroprene rubber and hydrogenated products thereof; ethylene-propylene copolymers, ethylene-α-olefin copolymers, and propylene-α-olefin copolymers. Saturated polyolefin rubbers; diene copolymers such as ethylene-propylene-diene copolymers, α-olefin-diene copolymers, diene copolymers, isobutylene-isoprene copolymers, and isobutylene-diene copolymers, and the like Halides and their hydrogenated products; acrylonitrile-butadiene copolymers and hydrogenated products thereof; vinylidene fluoride-trifluoride ethylene copolymers, vinylidene fluoride-hexafluoropropylene copolymers, vinylidene fluoride- Hexafluoropropylene-tetrafluoroethylene Fluorine rubbers such as ethylene copolymer and propylene-tetrafluoroethylene copolymer; urethane rubber, silicone rubber, polyether rubber, acrylic rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, propylene oxide rubber, and ethylene acrylic Special rubbers such as rubber; Norbornene monomer-ethylene or α-olefin copolymer, Norbornene monomer-ethylene-α-olefin terpolymer, Norbornene monomer ring-opening polymer, Norbornene Norbornene rubbery polymer such as hydrogenated ring-opening polymer of a monomer; Random copolymer or block of styrene-butadiene such as emulsion polymerization or solution polymerization styrene-butadiene rubber, high styrene rubber Copolymers and their hydrogenated products; -Random copolymers of aromatic vinyl monomers-conjugated dienes such as butadiene-styrene rubber, styrene-isoprene-styrene rubber and styrene-ethylene-butadiene-styrene rubber, and hydrogenated products thereof; styrene-butadiene-styrene rubber Linear or radial block copolymers of aromatic vinyl monomers-conjugated dienes such as styrene-isoprene-styrene rubber and styrene-ethylene-butadiene-styrene rubber, and styrenic thermoplastics such as hydrogenated products thereof An elastomer etc. are mentioned.

  From the viewpoint of heat resistance, the thermoplastic elastomer is more preferably subjected to hydrogenation at a portion other than the aromatic ring. Examples of such elastomers include styrene-ethylene-butadiene-styrene block copolymers, styrene-butadiene block copolymers, styrene-butadiene-styrene block copolymers, styrene-isoprene block copolymers, styrene-isoprene. -Styrene block copolymers, styrene-butadiene random copolymers, and hydrogenated products thereof. These are commercially available as SEPTON series (1001, 1020, 2002, 2004, 2005, 2006, 2007, 2104, 2063, 4033, 4044, 4055, 4077, 4099, 8004, 8006, 8007, 8104, 8076) manufactured by Kuraray. Has been.

  When the adhesive composition further contains an inert resin described later, the inert resin is 80 parts by mass or more and 90 parts by mass or less when the total of the active resin and the inert resin is 100 parts by mass. It is preferable that it is included in the range. When the content of the inactive resin in the adhesive composition is within the above range, the amount of the active resin that is included in the adhesive composition and forms a cross-link between molecules may fall within an appropriate range. it can. Therefore, it is possible to more reliably realize the suppression of warpage, the improvement of heat resistance, and the maintenance of solubility in the stripping solution.

  The film formed from an adhesive composition containing an active resin and an inert resin (if necessary) has a softening point of 100 ° C. or higher and 200 ° C. or lower, more preferably 120 ° C. or higher and 180 ° C. or lower. It has a softening point of When the softening point of the film is within the above range, excellent heat resistance and warpage can be more reliably realized.

<Crosslinking agent>
The adhesive composition according to the present invention essentially contains a crosslinking agent. The crosslinking agent is a compound having two or more functional groups that are reactive with the functional groups contained in the active resin. Accordingly, the type of crosslinking agent is selected according to the type of functional group contained in the active resin.

  As the crosslinking agent according to the present invention, an amino group-containing compound such as melamine, acetoguanamine, benzoguanamine, urea, ethylene urea, propylene urea, or glycoluril is reacted with formaldehyde or formaldehyde and a lower alcohol, and a hydrogen atom of the amino group is converted. Examples include compounds substituted with a hydroxymethyl group or a lower alkoxymethyl group, and compounds having an epoxy group.

  Of these, those using melamine are melamine crosslinking agents, those using urea are urea crosslinking agents, those using alkylene urea such as ethylene urea or propylene urea are alkylene urea crosslinking agents, and glycoluril is used. What was used was a glycoluril-based crosslinking agent, and what used an epoxy group-containing compound was called an epoxy-based crosslinking agent.

  Melamine-based cross-linking agents include compounds in which melamine and formaldehyde are reacted to replace amino group hydrogen atoms with hydroxymethyl groups, and melamine, formaldehyde and lower alcohols are reacted to lower amino group hydrogen atoms to lower levels. Examples thereof include compounds substituted with an alkoxymethyl group. Specific examples include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, and hexabutoxybutyl melamine. Among them, hexamethoxymethyl melamine is preferable.

  Urea-based cross-linking agents include compounds in which urea and formaldehyde are reacted to replace amino group hydrogen atoms with hydroxymethyl groups, and urea, formaldehyde and lower alcohols are reacted to lower amino group hydrogen atoms to lower levels. Examples thereof include compounds substituted with an alkoxymethyl group. Specific examples include bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, bisbutoxymethylurea, etc. Among them, bismethoxymethylurea is preferable.

  Examples of the alkylene urea-based crosslinking agent include compounds represented by the following general formula (1).

Wherein R ¹ and R ² are each independently a hydroxyl group or a lower alkoxy group, R ³ and R ⁴ are each independently a hydrogen atom, a hydroxyl group or a lower alkoxy group, and v is 0 or 1 It is an integer of ~ 2.)
When R ¹ and R ² are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and are linear or branched. R ¹ and R ² are the same or different from each other and are preferably the same. When R ³ and R ⁴ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and are linear or branched. R ³ and R ⁴ are the same or different from each other and are preferably the same. v is 0 or an integer of 1 to 2, and preferably 0 or 1. As the alkylene urea crosslinking agent, a compound in which v is 0 (ethylene urea crosslinking agent) and a compound in which v is 1 (propylene urea crosslinking agent) are particularly preferable.

  The compound represented by the general formula (1) can be obtained by a condensation reaction of alkylene urea and formalin and a reaction of the product with a lower alcohol.

  Specific examples of alkylene urea crosslinking agents include, for example, mono and dihydroxymethylated ethylene urea, mono and dimethoxymethylated ethylene urea, mono and diethoxymethylated ethylene urea, mono and dipropoxymethylated ethylene urea, mono and di Ethyleneurea based crosslinkers such as butoxymethylated ethyleneurea; mono and dihydroxymethylated propylene urea, mono and dimethoxymethylated propylene urea, mono and diethoxymethylated propylene urea, mono and dipropoxymethylated propylene urea, mono and di Propylene urea-based crosslinking agents such as butoxymethylated propylene urea; and 1,3-di (methoxymethyl) 4,5-dihydroxy-2-imidazolidinone, 1,3-di (methoxymethyl) -4,5-dimethoxy − - like and imidazolidinone.

  Examples of the glycoluril-based crosslinking agent include glycoluril derivatives in which the N position is substituted with one or both of a hydroxyalkyl group and an alkoxyalkyl group having 1 to 4 carbon atoms. The glycoluril derivative can be obtained by a condensation reaction of glycoluril and formalin and reacting the product with a lower alcohol.

  Specific examples of the glycoluril-based crosslinking agent include, for example, mono, di, tri, and tetrahydroxymethylated glycolurils; mono, di, tri, and tetramethoxymethylated glycolurils; mono, di, tri, and tetraethoxymethylated glycolurils Mono, di, tri and tetrapropoxymethylated glycolurils; and mono, di, tri and tetrabutoxymethylated glycolurils;

  The epoxy-based crosslinking agent is not particularly limited as long as it has an epoxy group, and can be arbitrarily selected and used. Among them, those having two or more epoxy groups are preferable. By having two or more epoxy groups, crosslinking reactivity is improved. The number of epoxy groups is preferably 2 or more, more preferably 2 to 4, and most preferably 2. The following are suitable as the epoxy-based crosslinking agent.

  The crosslinking agent is preferably contained in the range of 5% by weight to 20% by weight with respect to the weight of the active resin. If the content of the crosslinking agent in the adhesive composition is within the above range, the active resin is crosslinked (partially) to an appropriate degree. Therefore, it becomes easier to improve the heat resistance while maintaining the solubility in the release agent.

<Other components contained in the adhesive composition>
The adhesive composition according to the present invention includes miscible additives such as additional resins, plasticizers, and adhesion assistants for improving the performance of the adhesive, as long as the essential characteristics of the present invention are not impaired. What is conventionally used in the said field | areas, such as an agent, a stabilizer, a coloring agent, and surfactant, can further be added.

  Further, the viscosity of the adhesive composition may be adjusted by diluting with an organic solvent as long as the essential characteristics of the present invention are not impaired. Examples of the organic solvent include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and p-mentene; aliphatic hydrocarbons such as n-pentane, hexane, and heptane; and alicyclic hydrocarbons such as cyclohexane. be able to. As the organic solvent, one type may be selected and used, or two or more types may be selected and mixed.

  The usage-amount of the organic solvent is suitably selected according to the film thickness which desires to apply | coat an adhesive composition. Therefore, the amount used is not particularly limited as long as the adhesive composition has a concentration that can be applied onto a support such as a semiconductor wafer. Generally, the organic solvent is used in an amount within a range where the solid content concentration of the adhesive composition in the organic solvent and the adhesive composition has 20 to 70 mass%, more preferably 25 to 60 mass%. .

  As described above, when the adhesive composition according to the present invention is used, trouble and breakage at the time of wafer conveyance due to warpage of the adhesive layer, oozing and sinking of the adhesive layer in a high temperature process, and the adhesive layer Easy removal can be realized simultaneously.

[Stripping solution]
As a stripping solution for removing the adhesive composition according to the present invention, a stripping solution common in the field can be used. For example, the above-mentioned organic solvents can be used.

[Usage method of adhesive composition]
An example of the method of using the adhesive composition according to the present invention will be described below. The following description is an example to help understanding of the present invention as described as "example", and does not limit the present invention in any way.

  By applying the adhesive composition according to the present invention on a film to form an adhesive layer, it can be used as an adhesive film. The adhesive film which concerns on this invention is equipped with the adhesive bond layer containing one of the said adhesive composition on a film. The said adhesive film is obtained in the process of an adhesive film method. In the adhesive film method, an adhesive layer containing any one of the above-described adhesive compositions is formed on a film that temporarily becomes a base material such as a flexible film, and then dried, and then the adhesive film is used. This is a method of using by attaching to a workpiece.

  As described in the section of [Adhesive composition] above, the adhesive composition contains an active resin and an appropriate amount of a cross-linking agent. It remains soluble. That is, if the adhesive film according to the present invention is used, the trouble and breakage at the time of wafer conveyance due to the warp of the adhesive layer, the seepage and sinking of the adhesive layer in the high temperature process, and the easy removal of the adhesive layer are possible. It can be realized at the same time.

  The adhesive film may have a configuration in which a protective film is coated on the adhesive surface of the adhesive layer. When the structure is adopted, the protective film on the adhesive layer is peeled off and the exposed adhesive surface of the adhesive layer is superimposed on the workpiece, and then the film (flexible film) is formed from the adhesive layer. Etc.) can be easily provided on the workpiece.

  Here, the adhesive composition which concerns on this invention mentioned above can employ | adopt various utilization forms according to a use. For example, a method may be used in which the adhesive layer is formed by coating on a workpiece such as a semiconductor wafer in a liquid state. On the other hand, when the adhesive film according to the present invention is used, the film thickness uniformity and surface smoothness are compared with the case where the adhesive composition is directly applied to the workpiece to form the adhesive layer. It is possible to form a good adhesive layer.

  The film for forming an adhesive layer used in the production of the adhesive film according to the present invention can peel the adhesive layer formed on the film from the film, and the adhesive layer is covered with a protective substrate or a wafer. Any release film that can be transferred onto the treated surface may be used, and the other points are not particularly limited. Examples of the film for forming the adhesive layer include a flexible film made of a synthetic resin film made of polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyvinyl chloride, or the like having a film thickness of 15 μm or more and 125 μm or less. . The film is preferably subjected to a release treatment for facilitating transfer as necessary.

  The method for forming the adhesive layer on the film is not particularly limited as long as it is appropriately selected from known methods according to the desired film thickness or uniformity of the adhesive layer. Examples of known methods include applicators, bar coaters, wire bar coaters, roll coaters, curtain flow coaters, etc., and the thickness of the adhesive layer after drying formed on the film is 10 μm or more and 1000 μm or less. The method of apply | coating the adhesive composition which concerns on this invention is mentioned. In particular, a roll coater is preferable because it is suitable for forming an adhesive layer excellent in film thickness uniformity and efficiently forming a film having a large film thickness.

  Moreover, when using a protective film, if a protective film is a film which can be peeled from an adhesive bond layer, it will not specifically limit, For example, a polyethylene terephthalate film, a polypropylene film, a polyethylene film, etc. are preferable. Each protective film is preferably coated with silicon or baked. This is because peeling from the adhesive layer is easy. Although the thickness of a protective film is not specifically limited, It is preferable that they are 15 micrometers or more and 125 micrometers or less. This is because the flexibility of the adhesive film provided with the protective film can be secured.

  The method of using the adhesive film is not particularly limited. For example, when a protective film is used, the protective film is peeled off, and the exposed adhesive surface of the adhesive layer is overlaid on the workpiece, and then the film side. The method of thermocompression-bonding an adhesive bond layer to the surface of a to-be-processed body by rotating a heating roller from (the back surface side of the surface in which the adhesive bond layer was formed) is mentioned. In addition, if a protective film peeled from the adhesive film is wound up in a roll shape using a roller such as a winding roller, the protective film can be stored and reused.

  The adhesive composition according to the present invention is not particularly limited with respect to the use, but is suitably used as an adhesive composition for bonding a protective substrate used for precision processing of a semiconductor wafer to a substrate such as a semiconductor wafer. The adhesive composition of the present invention is suitably used as an adhesive composition (including an adhesive layer) for attaching the substrate to a support plate, particularly when grinding and thinning a substrate such as a semiconductor wafer. (For example, refer to JP-A-2005-191550).

  Examples of the adhesive composition according to the present invention are shown below. In addition, the Example shown below is the illustration which helps understanding of this invention, Comprising: This invention is not limited at all.

[Composition of adhesive composition]
A plurality of adhesive compositions having different compositions were prepared as compositions of Examples and Comparative Examples of the present invention. The composition of each of the prepared adhesive compositions is shown in Table 1 below. Each adhesive composition was prepared by adding a resin and an additive to a solvent and mixing them.

(Details of each component in each adhesive composition)
Resin 1 is SEBS: hydrogenated butylene-butadiene block copolymer (SEPTON 8007, manufactured by Kuraray Co., Ltd.) (represented by the following chemical formula (2)).
Resin 2 is α, ω-polybutadiene glycol (G3000, manufactured by Nippon Soda Co., Ltd.) having a hydroxyl group at the end of the molecular chain (represented by the following chemical formula (3)).
The cross-linking agent 1 is a methylated melamine resin (Nicalac MW-390, manufactured by Sanwa Chemical Co., Ltd.) (represented by the following chemical formula (4)).
The crosslinking agent 2 is a methylated urea resin (Nicalac MX-280, manufactured by Sanwa Chemical Co., Ltd.) (represented by the following chemical formula (5)).
The solvent is p-menthane.

(In the formula (2), k, l, m and n are integers of 1 or more)

(In formula (3), z is an integer of 1 or more)

  The resin 1 is a resin (inactive resin) that is inert to the crosslinking agent 1 and the crosslinking agent 2. Resin 2 is a resin (active resin) in which crosslinking agent 1 or crosslinking agent 2 reacts with the hydroxyl group to cause intermolecular crosslinking.

  The adhesive composition of Example 1 contains 10% by weight of the crosslinking agent 1 with respect to the resin 2. The adhesive composition of Example 2 contains 10% by weight of the crosslinking agent 2 with respect to the resin 2. The adhesive composition of Example 3 contains 5% by weight of the crosslinking agent 1 with respect to the resin 2. The adhesive composition of Example 4 contains 10% by weight of the crosslinking agent 1 with respect to the resin 2. The adhesive composition of Example 5 contains 20% by weight of the crosslinking agent 2 with respect to the resin 2. The adhesive composition of Comparative Example 3 contains 50% by weight of the crosslinking agent 1 with respect to the resin 2.

[Evaluation of adhesive composition]
About each of the said adhesive composition of an Example and a comparative example, heat resistance (degree that resin sinks), the grade which a curvature produces, and the ease of peeling (presence of a residue) were evaluated.

(Evaluation of heat resistance)
About each of the adhesive composition of an Example and a comparative example, the quantity which becomes a 50-micrometer-thick layer on a semiconductor wafer was spin-coated, and it baked at 110 degreeC, 150 degreeC, or 220 degreeC. Thereafter, the support plate was baked on the adhesive composition film at 150 ° C. to attach the support plate. The heat resistance of the semiconductor wafer affixed to the support plate using each adhesive composition is determined based on the amount of subsidence of the film of the adhesive composition after the heat resistance test (heat treatment for 1 hour in a vacuum at 200 ° C.) It was evaluated from the variation of the film thickness. The evaluation criteria are as follows.
○: Film thickness after heat resistance test> Film thickness before heat resistance test x 60%
Δ: film thickness after heat resistance test = film thickness before heat resistance test × 40-60%
X: Film thickness after heat resistance test <film thickness before heat resistance test x 40%
The results of evaluation according to this standard are shown in Table 2.

(Evaluation of warpage)
After performing the heat resistance test of each adhesive composition in the same manner as the evaluation of heat resistance, the film warpage of each adhesive composition was measured using a film warpage measuring device (TENCOR FLX-2908, manufactured by KLA Tencor Japan). The degree of was measured. The measurement results are shown in Table 2. In addition, unless the warpage exceeds 100 μm, it is assumed that it can withstand actual use.

(Confirmation of residue)
After performing the heat resistance test of each adhesive composition in the same manner as the evaluation of heat resistance, an operation of removing the film of each adhesive composition from the semiconductor wafer using a release agent (p-menthane) was performed. . After this removal, it was visually confirmed whether or not the adhesive composition was completely removed on the semiconductor wafer (the presence or absence of a residue). The results are shown in the table. In addition, when the residue was confirmed visually, it was judged that the solubility was low and it could not be used.

  As shown in Table 2, the adhesive compositions of Examples 1 to 5 were good in each evaluation of warpage, subsidence, and residue. That is, the adhesive compositions of Examples 1 to 5 are (1) less warped even when exposed to high temperatures, and therefore can prevent troubles and breakage during the transportation of the semiconductor wafer, and (2) the film during high temperature processing. It has been found that since the adhesiveness does not deteriorate, the semiconductor wafer can be appropriately fixed, and (3) it can be easily removed using a stripping solution after the high temperature treatment. The adhesive compositions of Examples 1 and 5 were particularly good because of less sinking.

  On the other hand, as shown in Table 2, the adhesive compositions of Comparative Examples 1 to 3 were softened during the high temperature treatment and greatly sunk, and oozing was confirmed from the end of the film (Comparative Examples 1 and 2). In addition, the warpage was severe and it was not sufficiently removed by the stripping solution (Comparative Example 3). Thus, the adhesive compositions of Comparative Examples 1 to 3 could not simultaneously achieve the effects (1) to (3) described above.

  As can be seen from the above results, the adhesive composition according to the present invention containing an active resin and a crosslinking agent has little warpage, excellent heat resistance, and can be easily peeled off. Therefore, the adhesive composition can cope with a process at a high temperature (for example, a temperature of 150 ° C. or more), is easily peeled without damaging the semiconductor wafer, and does not cause a problem during transportation. To improve.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can be used conveniently in the high temperature process applied to manufacture of various products can be provided. In particular, an adhesive composition suitable for a process of processing a semiconductor wafer or chip by being exposed to a high temperature environment of 150 ° C. or higher can be provided.

Claims (6)

An adhesive composition for temporarily bonding an object to an object,
The softening point of the film formed from the adhesive composition is in the range of 100 ° C. or higher and 200 ° C. or lower,
Contains a resin and a crosslinking agent,
The resin has a functional group reactive to the cross-linking agent;
The cross-linking agent that reacts with the functional group to cause intermolecular cross-linking in the resin is contained in a range of more than 0% by weight and less than 50% by weight with respect to the weight of the resin. Adhesive composition.   The adhesive composition according to claim 1, wherein the crosslinking agent is contained in a range of 5 wt% to 20 wt% with respect to the weight of the resin.   The adhesive composition according to claim 1 or 2, wherein the functional group is a hydroxyl group or a carboxyl group.   The adhesive composition according to any one of claims 1 to 3, wherein the resin has the functional group at a molecular chain terminal.   An inert resin that is inert to the cross-linking agent is further contained, and when the total of the inert resin and the resin is 100 parts by mass, the resin is 10 parts by mass or more and 20 parts by mass or less. It is contained by the range, The adhesive composition of any one of Claims 1-4 characterized by the above-mentioned.   The said softening point exists in the range of 120 to 180 degreeC, The adhesive composition of any one of Claims 1-5 characterized by the above-mentioned.