JP2023009147A - Heat-curable composition for forming flexible resin, flexible resin, and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To much further improve breaking elongation and flexibility with regard to a flexible resin formed by curing a heat-curable composition containing an epoxy resin.

SOLUTION: There is disclosed a heat-curable composition for forming a flexible resin containing an epoxy resin (A), and a thiol compound (B) having 2 or more thiol groups. The epoxy resin (A) includes a copolymerized epoxy resin which is a copolymer containing a constitutional unit having an aromatic group (A1) or an alicyclic group, and a constitutional unit having an oxyalkylene group or four or more C alkylene group.

SELECTED DRAWING: None

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention mainly relates to a thermosetting composition for forming a stretchable resin and a semiconductor device having a stretchable resin layer formed using the same.

Resin members constituting wearable devices, biosensors, connector members, and the like are sometimes required to have higher flexibility and stretchability than ever before. For example, a resin member that constitutes a wearable device is required to have high flexibility and stretchability so as to be easily attached to a curved surface of the body and to prevent poor connection due to attachment and detachment. Conventional elastic resins with high flexibility and stretchability are generally formed by liquid silicone or liquid polyurethane.

However, stretchable resins made from liquid silicone may lack adhesion to other materials. Elastic resins formed from liquid polyurethane tend to lack heat resistance.

On the other hand, Patent Literature 1 discloses a moisture-proof insulating paint containing copolymer rubber.

JP-A-2005-162986

A stretchable resin formed from a thermosetting composition containing an epoxy resin tends to have high adhesion to other materials and high heat resistance. However, there is room for improvement in terms of elongation at break and stretchability of the stretchable resin.

Accordingly, an object of one aspect of the present invention is to further improve the elongation at break and the stretchability of a stretchable resin formed by curing a thermosetting composition containing an epoxy resin.

One aspect of the present invention relates to a thermosetting composition for forming a stretchable resin, containing (A) an epoxy resin and (B) a thiol compound having two or more thiol groups. (A) The epoxy resin contains (A1) a copolymerized epoxy resin. (A1) Copolymer epoxy resin is a copolymer containing a structural unit having an aromatic group or an alicyclic group and a structural unit having an oxyalkylene group or an alkylene group having 4 to 8 carbon atoms.

Another aspect of the present invention relates to a stretchable resin comprising a cured product of the thermosetting composition for forming a stretchable resin. Yet another aspect of the present invention relates to a semiconductor device comprising a stretchable resin layer made of a cured product of the stretchable resin-forming thermosetting composition.

ADVANTAGE OF THE INVENTION According to this invention, the thermosetting composition which can form elastic resin which has sufficient elongation at break and elasticity is provided. The stretchable resin formed has good properties in terms of heat resistance and adhesion to many materials. The thermosetting composition according to one aspect of the present invention is also excellent in terms of storage stability. The thermosetting compositions of the present invention can be solventless. Solvent-free thermosetting compositions are advantageous in terms of handling and productivity compared to solvent-containing thermosetting compositions.

It is a stress-strain curve showing a measurement example of the stretch recovery rate. 1 is a cross-sectional view showing an embodiment of a semiconductor device; FIG. 1 is a cross-sectional view illustrating one embodiment of a flexible substrate and circuit components; FIG. FIG. 4 is a cross-sectional view showing one embodiment of a process of obtaining a plurality of semiconductor devices;

An embodiment of the present invention will be specifically described below, but the present invention is not limited to this. In the following embodiments, it goes without saying that the constituent elements (including element steps, etc.) are not necessarily essential, unless otherwise specified or clearly considered essential in principle. . This also applies to numerical values and ranges, which should not be construed as unduly limiting the present invention.

As used herein, the term "process" includes not only an independent process, but also when the intended action of the process is achieved even if it cannot be clearly distinguished from other processes. .
In this specification, the numerical range indicated using "to" indicates the range including the numerical values before and after "to" as the minimum and maximum values, respectively.
When referring to the amount of each component in the composition herein, when there are multiple substances corresponding to each component in the composition, unless otherwise specified, the multiple substances present in the composition means the total amount of

[Thermosetting composition for forming elastic resin]
A thermosetting composition according to one embodiment contains (A) an epoxy resin and (B) a thiol compound having two or more thiol groups. (A) The epoxy resin is a copolymer epoxy copolymer containing (A1) a structural unit having an aromatic group or an alicyclic group and a structural unit having an oxyalkylene group or an alkylene group having 4 to 8 carbon atoms. Contains resin. When this thermosetting composition is cured by, for example, reaction between epoxy groups and thiol groups, a stretchable resin having sufficient stretchability is formed. The thermosetting composition according to one embodiment may be a one-component thermosetting composition, and may be composed of (A) a main liquid containing an epoxy resin and (B) a curing agent liquid containing a thiol compound. It may be a two-part thermosetting composition composed of:

As used herein, "elasticity" means the property of being able to recover to its original shape or a shape close to it upon release from the load after being distorted by a tensile load. For example, a material that can recover to or near its original shape after being subjected to a strain of 50% by a tensile load can be said to be stretchable. More specifically, it can be said that a resin having a stretch recovery rate of 80% or more, which will be described later, is a stretchable resin.

<(A1) Copolymerized epoxy resin>
The copolymerized epoxy resin of component (A1) has a structural unit having an aromatic group or an alicyclic group as a rigid component and a structural unit having an alkylene group having 4 or more carbon atoms as a flexible component. Copolymerized epoxy resins usually have two epoxy groups located at both ends of the copolymer chain. By using this copolymerized epoxy resin, a cured product having both heat resistance reliability and flexibility can be obtained.

The copolymer epoxy resin is, for example, a copolymer of a diol having an aromatic group or an alicyclic group and a glycidyl ether having an alkylene group having 4 to 8 carbon atoms, or a diol having an alkylene group having 4 to 8 carbon atoms and an aromatic It may be a copolymer with a diglycidyl ether having a group or alicyclic group, or a combination thereof. A diol having an aromatic group or an alicyclic group may be a compound represented by the following formula (21). The glycidyl ether having an alkylene group with 4 or more carbon atoms may be a compound represented by the following formula (31). The diol having an alkylene group with 4 to 8 carbon atoms may be a compound represented by the following formula (22). A diol having an aromatic group or an alicyclic group may be a compound represented by the following formula (32). In these formulas, R ^a represents an aromatic group or an alicyclic group, and R ^b represents an alkylene group having 4 or more carbon atoms. R ^b may be an alkylene group having 4 to 8 carbon atoms.

The aromatic group may be, for example, an aromatic hydrocarbon group such as benzene ring, naphthalene ring, anthracene ring and pyrene ring, or an aromatic heterocyclic group such as pyrrole ring and thiophene ring. Aromatic groups may be groups having two or more aromatic rings that are attached by direct bonds, methanediyl groups, 2,2-propanediyl groups, quaternary spiro carbon atoms or combinations thereof, Examples thereof include a biphenylene group, a tetramethylbiphenylene group, a group having a cardo structure, and a fluorene ring. The alicyclic group may be, for example, a cyclohexane ring or a dicyclopentadiene group.

A known alkylene group having 4 or more carbon atoms can be used. For example, an alkylene group having 4 or more carbon atoms may be a 1,4-butanediyl group or a 1,6-hexanediyl group. An oxyalkylene group can be, for example, an oxyethylene group, an oxypropylene group, or an oxybutylene group.

Examples of copolymerized epoxy resins include copolymers of bisphenol F and 1,6-hexanediol diglycidyl ether, copolymers of 1,6-hexanediol and bisphenol F diglycidyl ether, bisphenol F and 1,4 - butanediol diglycidyl ether copolymer, 1,4-butanediol and bisphenol F diglycidyl ether copolymer, bisphenol A and 1,6-hexanediol diglycidyl ether copolymer, 1, Copolymers of 6-hexanediol and bisphenol A diglycidyl ether, copolymers of bisphenol A and 1,4-butanediol diglycidyl ether, copolymers of 1,4-butanediol and bisphenol A diglycidyl ether , a copolymer of tetramethylbiphenol and 1,6-hexanediol diglycidyl ether, a copolymer of 1,6-hexanediol and tetramethylbiphenol diglycidyl ether, tetramethylbiphenol and 1,4-butanediol diol Copolymer with glycidyl ether, copolymer of 1,4-butanediol and tetramethylbiphenol diglycidyl ether, copolymer of biphenol and 1,6-hexanediol diglycidyl ether, 1,6-hexanediol and biphenol diglycidyl ether, copolymer of biphenol and 1,4-butanediol diglycidyl ether, copolymer of 1,4-butanediol and biphenol diglycidyl ether, 1,4-naphthalenediol and 1,6-hexanediol diglycidyl ether, copolymers of 1,6-hexanediol and 1,4-naphthalenediol diglycidyl ether, 1,4-naphthalenediol and 1,4-butane Copolymer with diol diglycidyl ether, copolymer of 1,4-butanediol and 1,4-naphthalenediol diglycidyl ether, copolymer of 1,6-naphthalenediol and 1,6-hexanediol diglycidyl ether a copolymer, a copolymer of 1,6-hexanediol and 1,6-naphthalenediol diglycidyl ether, a copolymer of 1,6-naphthalenediol and 1,4-butanediol diglycidyl ether, and A copolymer of 1,4-butanediol and 1,6-naphthalenediol diglycidyl ether can be mentioned. These may be used individually by 1 type, and may be used in arbitrary combinations of 2 or more types.

(A1) Examples of commercially available copolymer epoxy resins include "YX7105" and "YX7110" (copolymers of bisphenol F and 1,6-hexanediol diglycidyl ether) manufactured by Mitsubishi Chemical Corporation. .

(A1) The content of copolymerized epoxy resin may be 30 parts by mass or more, or 50 parts by mass or more with respect to 100 parts by mass of the total amount of (A) epoxy resin. When the content of component (A1) is 30 parts by mass or more, a cured product having particularly high flexibility can be easily obtained.

<(B) a thiol compound having two or more thiol groups>
The thiol compound of component (B) has two or more thiol groups (--SH). (B) The thiol compound may have 2 to 5, 3 to 5, or 3 to 4 thiol groups. (B) The thiol group possessed by the thiol compound may be a secondary thiol group. A thermosetting composition containing a thiol compound having a secondary thiol group can have particularly excellent storage stability. A secondary thiol group is a thiol group attached to a carbon atom that is attached to two carbon atoms and one hydrogen atom.

(B) The thiol compound may be a compound represented by the following formula (1), (2) or (3).

In formula (1), X ¹ , X ² , X ³ and X ⁴ each independently represent a monovalent group having a thiol group or a hydrogen atom, and among X ¹ , X ² , X ³ and X ⁴ Two or more are monovalent groups having a thiol group. In formula (2), X ⁵ , X ⁶ and X ⁷ each independently represent a monovalent group having a thiol group or a hydrogen atom, and two or more of X ⁵ , X ⁶ and X ⁷ are thiol groups is a monovalent group having In formula ( ³ ), ^X8 and X9 each independently represent a monovalent group having a thiol group, and ^R1 represents an alkylene group. R ¹ may be an alkylene group having 2 to 10 carbon atoms. The group having a thiol group may be a group represented by the following formula (11) having a secondary thiol group, or a group represented by the following formula (12) or (13) having a primary thiol group may be In formula (11), R ² represents an alkylene group. ^In formula (12), R3 represents an alkylene group. In formula (13), ^R4 represents an alkylene group. R ² may be an alkylene group having 1 to 8 carbon atoms. R ³ and R ⁴ may be an alkylene group having 2 to 10 carbon atoms.

Examples of the thiol compound having a secondary thiol group include pentaerythritol tetrakis (3-mercaptobutyrate) represented by the following formula (1a) (for example, Showa Denko Co., Ltd. "Karenzu MT PE-1"), 1,3,5-tris(2-(3-mercaptobutyryloxy)ethyl)-1,3,5-triazine-2,4,6(1H,3H,5H) represented by the following formula (2a) - Trione (e.g., "Karenzu MT NR-1" manufactured by Showa Denko Co., Ltd.), and 1,4-bis(3-mercaptobutyryloxy)butane represented by the following formula (3a) (e.g., Showa Denko "Karenzu MT BD-1" manufactured by Co., Ltd.).

Other examples of thiol compounds having a secondary thiol group include ethylene glycol bis (3-mercaptobutyrate), trimethylolethane tris (3-mercaptobutyrate), butanediol bis (3-mercaptobutyrate), penta erythritol tri(3-mercaptobutyrate), trimethylolethane (3-mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), and dipentaerythritol hexakis(3-mercaptobutyrate).

Other examples of thiol compounds having a primary thiol group include pentaerythritol trippropanethiol, 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1 ,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,10-decanedithiol, 1,3-benzenedithiol, 1,4-benzenedithiol, 4,4′-thiobisbenzenethiol , 4,4′-biphenyldithiol, 1,5-dimercaptonaphthalene, 4,5-bis(mercaptomethyl)-ortho-xylene, 1,3,5-benzenetrithiol, 1,4-butanediol bis(thio glycolate), dithioethritol, 3,6-dioxa-1,8-octanedithiol, 3,7-dithia-1,9-nonanedithiol, bis(2-mercaptoethyl) sulfide, ethylene glycol bis(mercaptoacetate) ), ethylene glycol bis (3-mercaptopropionate), ethylene glycol bis (3-mercaptoisobutyrate), butanediol bis (mercaptoacetate), butanediol bis (3-mercaptopropionate), butanediol bis ( 3-mercaptoisobutyrate), pentaerythritol tri (mercaptoacetate), pentaerythritol tri (3-mercaptopropionate), pentaerythritol tri (3-mercaptoisobutyrate), pentaerythritol tetrakis (mercaptoacetate), pentaerythritol Tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptoisobutyrate), trimethylolethane (mercaptoacetate), trimethylolethane (3-mercaptopropionate), trimethylolethane (3-mercaptoisobutyrate) butyrate), trimethylolpropane tris (mercaptoacetate), trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tris (3-mercaptoisobutyrate), dipentaerythritol hexakis (mercaptoacetate), di Pentaerythritol hexakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptoisobutyrate), 1,4-bis (3-mercaptopropyloxy) butane, tris [( 3-mercaptopropionyloxy)ethyl]isocyanurate, and tetraethylene glycol bis(3-mercaptopropionate).

The thiol compounds exemplified above can be used alone or in combination of two or more.

(B) The thiol equivalent (thiol group equivalent) of the thiol compound is 0.5 to 1.5, or 0.8 to 1.2 with respect to the total epoxy equivalent of the (A) epoxy resin. good. When the thiol equivalent of the thiol compound is within this range, unreacted (A) epoxy resin and (B) thiol compound are less likely to remain in the cured product.

<(A2) Monofunctional epoxy resin having an alkyl group having 6 or more carbon atoms>
The thermosetting composition according to one embodiment may further contain (A2) a monofunctional epoxy resin having an alkyl group with 6 or more carbon atoms as the (A) epoxy resin. The (A2) component monofunctional epoxy resin contains one or more epoxy compounds having an alkyl group having 6 or more carbon atoms and one epoxy group. The number of carbon atoms in the alkyl group may be 8 or more, 20 or less, or 17 or less. When the number of carbon atoms in the alkyl group is within these numerical ranges, the cured product tends to be less cloudy. (A2) The alkyl group having 6 or more carbon atoms contained in the monofunctional epoxy resin may be a linear alkyl group.

(A2) The monofunctional epoxy resin may contain a glycidyl ether compound represented by the following formula (5), a glycidyl ester compound represented by the following formula (6), or a combination thereof. R ⁵ and R ⁶ in formulas (5) and (6) are alkyl groups having 6 or more carbon atoms.

(A2) Examples of monofunctional epoxy resins include a glycidyl ether compound having an alkyl group having 12 to 13 carbon atoms (eg, "ADEKA GLYCIROL ED-502" manufactured by ADEKA Corporation), and an alkyl group having 17 carbon atoms. (eg, "Denacol EX-1113" manufactured by Nagase ChemteX Co., Ltd.). These compounds can be used individually or in combination of 2 or more types.

(A2) The content of the monofunctional epoxy resin may be 60 parts by mass or less, or 50 parts by mass or less, or 10 parts by mass or more with respect to 100 parts by mass of the total amount of (A) the epoxy resin. good. When the content of component (A2) is within these numerical ranges, there is a tendency that a cured product as a stretchable resin is formed particularly easily.

<(A3) Alicyclic group-containing polyfunctional epoxy resin>
The thermosetting composition according to one embodiment may contain (A3) an alicyclic group-containing polyfunctional epoxy resin as (A) the epoxy resin. The alicyclic group-containing polyfunctional epoxy resin of component (A3) is an epoxy resin having an alicyclic group and two or more epoxy groups, and is different from the copolymerized epoxy resin of component (A1). The alicyclic group may be, for example, a cyclohexane ring or a dicyclopentadiene group.

Examples of polyfunctional epoxy resins containing alicyclic groups include dicyclopentadiene type epoxy resins (eg, "EPICLON HP-7200 series" manufactured by DIC Corporation), 3,4-epoxycyclohexylmethyl-3',4'- Epoxy cyclohexane carboxylate (e.g., "Celoxide 2021P, Celoxide 2081, Celoxide 8000" manufactured by Daicel Corporation), hydrogenated bisphenol A type epoxy resin (e.g., "Epikote YX8000, Epicote YX8034, Epicote YL8040" manufactured by Mitsubishi Chemical Corporation) ), 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (for example, "EHPE3150" manufactured by Daicel Corporation), butanetetracarboxylic acid tetra (3,4-epoxycyclohexylmethyl)-modified ε-caprolactone (e.g., “Epolead GT-401” manufactured by Daicel Corporation), silicone oligomer having an alicyclic group and an epoxy group (e.g., “Shin-Etsu Chemical Co., Ltd.” X-40-2670"). From the viewpoint of heat resistance reliability, (A3) the alicyclic-containing polyfunctional epoxy resin may contain a dicyclopentadiene type epoxy resin. These epoxy resins can be used alone or in combination of two or more.

The content of (A3) alicyclic group-containing polyfunctional epoxy resin may be 5 parts by mass or more, or may be 10 parts by mass or more, and 50 parts by mass or less with respect to 100 parts by mass of the total amount of (A) epoxy resin. , or 40 parts by mass or less. When the content of component (A3) is 5 parts by mass or more, there is a tendency that a cured product having particularly high strength and heat resistance is formed. When the content of component (A3) is 50 parts by mass or less, the cured product tends to exhibit even higher stretchability.

<Other ingredients>
The thermosetting composition according to one embodiment may contain other components, if necessary, in addition to (A) the epoxy resin and (B) the thiol compound described above. (A) Epoxy resin may contain epoxy resins other than components (A1), (A2) and (A3). However, the ratio of the total amount of components (A1), (A2) and (A3) to the total amount of (A) epoxy resin is usually 80 to 100% by mass, or 90 to 100% by mass. The total amount of (A) the epoxy resin and (B) the thiol compound is 50 to 100% by mass, 60 to 100% by mass, 70 to 100% by mass with respect to the mass of the portion of the thermosetting composition excluding the solvent, It may be 80 to 100% by mass, or 90 to 100% by mass.

The thermosetting composition according to one embodiment includes inorganic fine particles, a curing catalyst, an antifoaming agent, a leveling agent, a silane coupling agent, an antioxidant, an anti-yellowing agent, an ultraviolet absorber, a visible light absorber, and a colorant. , plasticizers, and flame retardants. Examples of inorganic fine particles include silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), barium carbonate (BaCO ₃ ), talc (3MgO.4SiO ₂ .H ₂ O), zinc oxide (ZnO ), barium sulfate (BaSO ₄ ), organic bentonites, and hydrotalcites. Examples of curing catalysts include tertiary amines, imidazoles, phosphorus compounds, quaternary ammonium salts, and organometallic salts. Defoamers and leveling agents can be, for example, silicone-based, fluorine-based, or polymeric. Silane coupling agents can be, for example, thiazole-based or triazole-based. The thermosetting composition may be a solvent-containing resin varnish.

[Stretchable Resin/Stretchable Resin Layer]
The stretchable resin according to one embodiment consists of a cured product formed by thermal curing of the thermosetting composition according to the embodiment described above. The stretchable resin can have any shape, and may form, for example, a stretchable resin layer.

The stretchable resin or stretchable resin layer according to one embodiment can be used, for example, as a sealing layer or protective film for wearable devices, biosensors, and connector members, or as a protective film for the wiring of a flexible substrate.

The elastic resin may have an elongation at break of 100% or more in a tensile test. If the elongation at break is 100% or more, sufficient tensile strength can be obtained.

The stretchability of the stretchable resin can be evaluated using the stretch recovery rate measured by the following procedure including two tensile tests as an index.
1) A strip-shaped elastic resin having a length of 40 mm and a width of 5 mm is prepared as a test piece.
2) The test piece is held by chucks with a chuck-to-chuck distance of 20 mm, and the test piece is pulled to a displacement amount (strain) X in the first tensile test.
3) Return the chuck to its initial position.
4) Perform a second tensile test and record the amount of displacement (strain) Y in the section where the load is applied.
5) The stretch recovery rate is calculated by the formula: stretch recovery rate R (%) = (Y/X) x 100.
A tensile test is performed in a 25 degreeC environment. X can be set to a displacement amount of 10 mm (50% strain). As the testing machine, for example, a microforce testing machine (Illinois Tool Works Inc, "Instron 5948") can be used. FIG. 1 is an example of a stress-strain curve obtained from a tensile test to determine stretch recovery.

The stretch recovery rate may be 80% or more, 85% or more, or 90% or more from the viewpoint of resistance to repeated use. The upper limit of the stretch recovery rate is 100%. The thermosetting composition according to the above embodiment can usually easily form a cured product exhibiting a stretch recovery rate of 80%.

The stretchable resin may have a tensile modulus of 0.1 MPa or more and 50 MPa or less. When the tensile modulus is 0.1 MPa or more and 50 MPa or less, the stretchable resin can be stretched more easily. From the same point of view, the elastic modulus in tension of the elastic resin may be 0.1 MPa or more and 30 MPa or less, or 0.1 MPa or more and 10 MPa or less.

The elastic resin or elastic resin layer is formed by disposing a thermosetting composition in a desired form by a method such as dispensing, dipping, various coatings or casting, and then thermosetting the thermosetting composition. It can be formed by a method comprising: The heating conditions for heat curing may be set within a range in which heat curing proceeds sufficiently, and may be, for example, a temperature of 100.degree. C. to 200.degree.

[Semiconductor device]
FIG. 2 is a cross-sectional view showing one embodiment of a semiconductor device. A semiconductor device 100 shown in FIG. 2 includes a flexible substrate 1 having elasticity, a circuit component 2 , and a sealing resin layer 3 . A circuit component 2 is mounted on the flexible substrate 1 . The encapsulating resin layer 3 can be a stretchable resin formed from the thermosetting composition according to the embodiment described above. The sealing resin layer 3 seals the flexible substrate 1 and the circuit component 2, thereby protecting them.

Flexible substrate 1 may be a resin film containing at least one resin selected from the group consisting of polyimide resin, acrylic resin, silicone resin, urethane resin, bismaleimide resin, epoxy resin, and polyethylene glycol resin. From the viewpoint of excellent stretchability, the flexible substrate 1 is made of polyimide resin, acrylic resin, silicone resin, urethane resin, long-chain alkyl chain (for example, alkyl having 1 to 20 carbon atoms) having a siloxane group, an aliphatic ether group, or a diene structure. chain), an epoxy resin, and a resin film containing at least one resin selected from the group consisting of a polyethylene glycol resin having a rotaxane structure. From the same point of view, the flexible substrate 1 is at least one selected from the group consisting of polyimide resins, silicone resins, urethane resins having a siloxane group, an aliphatic ether group or a diene structure, and bismaleimide resins having a long alkyl chain. It may be a resin film containing a seed resin.

The circuit component 2 can be one type or two or more types of components. Circuit component 2 may be, for example, a control circuit, a memory chip, a light emitting diode (LED), an RF tag (RFID), a temperature sensor, an acceleration sensor, or a combination thereof.

The semiconductor device 100 includes, for example, a step of mounting a circuit component 2 on a flexible substrate 1 and a step of forming a sealing resin layer 3 for sealing the flexible substrate 1 and the circuit component 2, as shown in FIG. It can be manufactured by a method. The sealing resin layer 3 is formed by curing a thermosetting composition film formed on the flexible substrate 1 . The film of the thermosetting composition is formed, for example, by coating or printing the thermosetting composition on the flexible substrate 1 and the circuit component 2, or by immersing the flexible substrate 1 and the circuit component 2 in the thermosetting composition. can be formed by

If necessary, as shown in FIG. 4, a plurality of semiconductor devices may be obtained by forming a sealing structure including a plurality of portions to be semiconductor devices, and cutting and separating this structure. Thereby, a plurality of semiconductor devices can be collectively manufactured.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

1. Raw material (A1) Copolymerized epoxy resin YX7105: manufactured by Mitsubishi Chemical Corporation, copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether, epoxy equivalent 487
(B) Thiol compound PEPT: Pentaerythritol trippropanethiol, trifunctional primary thiol, molecular weight 358.6, manufactured by SC Organic Chemical Co., Ltd.
・ PE-1: Karenz MT PE-1, manufactured by Showa Denko Co., Ltd., pentaerythritol tetrakis (3-mercaptobutyrate, tetrafunctional secondary thiol, molecular weight 544
(A2) Monofunctional epoxy resin having an alkyl chain of 6 or more carbon atoms ED-502: Adeka glycyrrol ED-502, manufactured by ADEKA Corporation, glycidyl ether of alkyl alcohol having 12 or 13 carbon atoms, epoxy equivalent 320
(A3) Alicyclic group-containing polyfunctional epoxy resin HP-7200L: EPICLON HP-7200L, manufactured by DIC Corporation, dicyclopentadiene type epoxy resin, epoxy equivalent 248
(acid anhydride)
・ HN-5500: manufactured by Hitachi Chemical Co., Ltd., 3 or 4-methyl-hexahydrophthalic anhydride, molecular weight 168
(Curing catalyst)
・ 2E4MZ: Curesol 2E4MZ, manufactured by Shikoku Kasei Co., Ltd., 2-ethyl-4-methylimidazole (other epoxy resins)
・Celoxide 2081: manufactured by Daicel Corporation, ε-caprolactone-modified 3′,4′-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, epoxy equivalent 200
・ Denacol EX-991L: manufactured by Nagase ChemteX Co., Ltd., polyether glycol diglycidyl ether, epoxy equivalent 450
・ Denalex R15-EPT: manufactured by Nagase ChemteX Co., Ltd., polybutadiene / hydrogenated polybutadiene skeleton-containing bifunctional epoxy resin, epoxy equivalent 910
・ Denalex R45-EPT: manufactured by Nagase ChemteX Co., Ltd., bifunctional epoxy resin containing polybutadiene/hydrogenated polybutadiene skeleton, epoxy equivalent 1570

2. Preparation Example 1 of resin varnish (thermosetting composition for forming elastic resin)
Put 60.0 parts by mass of YX7105, 14.7 parts by mass of PEPT, and 0.1 part by mass of CURESOL 2E4MZ in a plastic container with a lid, and put the mixture in a rotation/revolution mixer (manufactured by Thinky Co., Ltd. "ARE- 250") to prepare a resin varnish for forming a stretchable resin.

Examples 2-7, Comparative Examples 1-5
Resin varnishes of Examples 2 to 7 and Comparative Examples 1 to 5 were prepared in the same manner as in Example 1 except that the compounding ratio (parts by mass) shown in Table 1 was changed. The resin varnish of Comparative Example 1 contains an acid anhydride instead of (B) the thiol compound. The resin varnishes of Comparative Examples 2 to 5 contain (A1) other epoxy resins having a flexible structure in place of the copolymerized epoxy resin.

3. Preparation of film for evaluation A release agent ("Daifree GA-7500" manufactured by Daikin Industries, Ltd.) is applied to the bottom of an aluminum container (L102 mm × W45 mm × H23 mm), and the coating is applied using a hot air heating furnace. The bottom of the container was demolded by heating at 120° C. for 3 minutes. Then, the resin varnish of each example and comparative example was poured into an aluminum container. The resin varnish in the aluminum container was cured by heating at 120° C. for 1 hour to obtain an evaluation film (thickness 1 mm) composed of a cured product of the thermosetting composition.

4. Evaluation [modulus of elasticity, elongation]
A test piece having a length of 40 mm and a width of 5 mm was cut from the film for evaluation. A tensile test of this test piece was performed using an autograph ("EZ-S" manufactured by Shimadzu Corporation) to obtain a stress-strain curve. The obtained stress-strain curve was used to determine the elastic modulus and breaking elongation of the cured product. The tensile test was performed under the conditions of a chuck-to-chuck distance of 20 mm and a tensile speed of 50 mm/min. The modulus of elasticity is the value at a load of 0.1 to 0.5 N, and the elongation is the elongation (elongation at break) when the test piece breaks. Since no cured product was formed from the resin varnish of Comparative Example 2, the elastic modulus and elongation of the cured product could not be measured.

[Stretch recovery rate]
A test piece having a length of 40 mm and a width of 5 mm was cut from the film for evaluation. This test piece was subjected to a tensile test twice using a microforce tester ("Instron 5948" manufactured by Illinois Tool Works Inc.). A test piece was sandwiched between a pair of chucks, and a tensile stress was applied to the test piece up to a displacement amount (strain) of X in the first tensile test. Next, the chuck was returned to the initial position, and when the tensile test was performed to the displacement (strain) X again, the displacement (strain) Y in the section where the load was applied was measured. The stretch recovery rate R was determined by the formula: R=(Y/X)×100. In this measurement, the initial length (distance between chucks) was 20 mm, and X was 10 mm (strain 50%). The film formed from the resin varnish of Comparative Example 4 broke before reaching 50% strain in the first tensile test.

[Adhesion to polyimide]
The resin varnish of each example was applied to a polyimide film having a thickness of 50 μm (“Kapton 200EN” manufactured by Toray DuPont Co., Ltd.) using a film applicator (Tester Sangyo Co., Ltd.). The cured film was cured under the curing conditions shown in 2. The cured film thus formed was cut with grids at intervals of 1 mm, and the cured film was divided into 100 square portions. The adhesive tape was strongly pressed, and the edge of the adhesive tape was peeled off at once at an angle of 45. Then, based on the number of squares that did not peel off from the polyimide film among the 100 squares, the adhesion was evaluated as follows. It was evaluated in 3 stages.
A: 100 (no peeling)
B: 95-99
C: less than 95

[Viscosity (storage stability)]
The initial viscosity of the resin varnish of each example and the viscosity at 25°C after storage at room temperature (25°C) for 24 hours were measured with an E-type viscometer ("TVE25H" manufactured by Toki Sangyo Co., Ltd.). The storage stability of the resin varnish was evaluated based on the change in viscosity.

Cured products (elastic resins) formed from the resin varnishes of Examples exhibited a high elongation at break of 130% or more and a high recovery from stretching of 90% or more. In particular, the cured products (elastic resins) formed from the resin varnishes of Examples 3 to 7 exhibited very high elongation at break exceeding 200%. The resin varnishes of Examples 6 and 7 using a thiol compound having a secondary thiol group show little increase in viscosity after storage for 24 hours at room temperature and are excellent in storage stability.

DESCRIPTION OF SYMBOLS 1... Flexible board, 2... Circuit component, 3... Sealing resin layer (elastic resin), 100... Semiconductor device.

Claims (10)

(A) an epoxy resin;
(B) a thiol compound having two or more thiol groups;
contains
(A) The epoxy resin is a copolymer epoxy resin containing (A1) a structural unit having an aromatic group or an alicyclic group and a structural unit having an oxyalkylene group or an alkylene group having 4 or more carbon atoms. including,
A thermosetting composition for forming an elastic resin. 2. The thermosetting composition for forming a stretchable resin according to claim 1, wherein (A) the epoxy resin further comprises (A2) a monofunctional epoxy resin having an alkyl group having 6 or more carbon atoms. (A) the epoxy resin further includes (A3) an alicyclic group-containing polyfunctional epoxy resin having an alicyclic group, and (A3) the alicyclic group-containing polyfunctional epoxy resin is different from (A1) the copolymerized epoxy resin 3. The thermosetting composition for forming a stretchable resin according to claim 1, which is a compound. (A1) The thermosetting composition for forming a stretchable resin according to any one of claims 1 to 3, wherein the copolymerized epoxy resin comprises a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether. thing. (A2) The thermosetting composition for forming a stretchable resin according to any one of claims 1 to 4, wherein the monofunctional epoxy resin is a monofunctional epoxy resin having an alkyl group having 6 to 17 carbon atoms. (A3) The thermosetting composition for forming a stretchable resin according to any one of claims 1 to 5, wherein the alicyclic group-containing polyfunctional epoxy resin comprises a polyfunctional epoxy resin having a dicyclopentadiene group. (B) The thermosetting composition for forming a stretchable resin according to any one of claims 1 to 6, wherein the thiol compound contains a thiol compound having a secondary thiol group. (A1) The content of the copolymerized epoxy resin (A) is 50 parts by mass or more based on 100 parts by mass of the epoxy resin (A). Composition. A stretchable resin comprising a cured product of the thermosetting composition for forming a stretchable resin according to any one of claims 1 to 8. A semiconductor device comprising a stretchable resin layer comprising a cured product of the thermosetting composition for forming a stretchable resin according to any one of claims 1 to 8.

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