JP7158184B2 - Sealing sheet and method for producing electronic element device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sealing sheet and a method for producing an electronic element device, and more particularly to a sealing sheet and a method for producing an electronic element device using the same.

Conventionally, an electronic element device is manufactured by pressing a sealing sheet against a substrate and an electronic element mounted thereon to form a sealing layer that embeds and seals the electronic element. is known (see, for example, Patent Document 1).

JP 2016-089091 A

However, it protrudes upward from the electronic element mounted on the substrate, and the peripheral side surface of the electronic element and the surface of the substrate on which the electronic element is mounted are perpendicular to each other.

For this reason, when embedding the electronic element with the sealing sheet, the space between the peripheral side surface of the electronic element and the peripheral surface of the electronic element on the substrate cannot be completely sealed with the sealing sheet. The sheet for encapsulation tends to float up, and a large gap is likely to be formed defined by the peripheral side surface of the electronic element, the surface of the substrate, and the back surface of the floated sealing sheet. Therefore, there is a problem that the reliability of the electronic element device having a large gap is lowered.

On the other hand, the sealing sheet softens when sealing the electronic element. material protrudes to the outside of the substrate and eventually contaminates its surroundings.

The present invention provides a sheet for encapsulation and a method for manufacturing an electronic element device, which can reliably seal an electronic element while suppressing protrusion to the outside and can manufacture an electronic element device with excellent reliability. .

The present invention (1) is a sealing sheet used to form a sealing layer for sealing an electronic element mounted on one side in the thickness direction of a substrate, and has a viscosity at 90°C of 5 kPa· s or more and the maximum length L measured in the following sealing test is 150 μm or less.

<Sealing test>
A test substrate made of glass having a length of 10 mm and a thickness of 400 μm in each of a first direction orthogonal to the thickness direction and a second direction orthogonal to the thickness direction and the first direction was placed on one surface in the thickness direction of the test substrate. A certain rectangular test element is arranged, and under the conditions of 25° C. and 1330 Pa, the rectangular sealing sheet having a length of 20 mm in each of the first direction and the second direction and a thickness of 260 μm is prepared. , pressurized against the test element for 60 seconds at 2 MPa so as to overlap the test element in the thickness direction, and then heat the sealing sheet at 150 ° C. for 1 hour, forming the sealing layer; Facing at least one end surface of the test element in at least one of the first direction and the second direction, one surface in the thickness direction of the test substrate, and one surface in the thickness direction A test gap defined by the other side in the thickness direction of the sealing layer is formed, and the maximum length L of the test gap in the one direction is measured.

Since this sealing sheet has a viscosity of 5 kPa·s or more at 90° C., when the sealing sheet is heated to seal the electronic element, the sealing sheet is softened and excessively It is possible to reliably embed the electronic element while suppressing the flow of the material of the sealing sheet and suppressing the protrusion of the material of the sealing sheet. Therefore, this encapsulating sheet can suppress contamination to the surroundings while being excellent in encapsulating properties for electronic elements.

On the other hand, since this sealing sheet has a short maximum length L of 150 μm or less, which is measured in a sealing test, it can follow a fine uneven structure without gaps, and has excellent water resistance and weather resistance. An electronic element device with excellent reliability can be manufactured.

Therefore, according to this sealing sheet, it is possible to reliably seal the electronic element while suppressing the protrusion of the material of the sealing sheet, and to manufacture an electronic element device having excellent reliability.

The present invention (2) includes the encapsulating sheet according to (1), which has a viscosity at 90° C. of 200 kPa·s or less.

The present invention (3) includes the encapsulating sheet according to (1) or (2), wherein the encapsulating layer has a linear expansion coefficient of 20 ppm/° C. or less.

The present invention (4) includes the encapsulating sheet according to any one of (1) to (3), containing 80% by mass or more of an inorganic filler.

The present invention (5) comprises (1) to (4) containing 2% by mass or more of at least one bifunctional epoxy resin selected from the group consisting of bisphenol A type epoxy resins and bisphenol F type epoxy resins. ), including the sheet for sealing according to any one of

In the present invention (6), the sealing layer for sealing the electronic element is formed by pressing the sealing sheet according to any one of (1) to (5) against the electronic element and heating it. A method of manufacturing an electronic device device is included, comprising the step of forming.

In this method for manufacturing an electronic element device, since the viscosity of the sealing sheet at 90° C. is 5 kPa·s or more, when the sealing sheet is heated to seal the electronic element, the sealing sheet While being softened, the electronic element can be reliably embedded while suppressing excessive flow and suppressing protrusion of the material of the sealing sheet. Therefore, this encapsulating sheet can suppress contamination to the surroundings while being excellent in encapsulating properties for electronic elements.

On the other hand, the sealing sheet has a short maximum length L of 150 μm or less, which is measured in a sealing test, so it can follow even a fine uneven structure without gaps, and has excellent water resistance and weather resistance. It is possible to manufacture an electronic element device having excellent properties.

Therefore, according to this method for manufacturing an electronic element device, it is possible to reliably seal the electronic element while suppressing the protrusion of the material of the sealing sheet, thereby manufacturing an electronic element device having excellent reliability.

According to the encapsulating sheet and the method for producing an electronic element device of the present invention, it is possible to reliably enclose an electronic element while suppressing the protrusion of the material of the encapsulating sheet, thereby producing an electronic element device having excellent reliability. be able to.

1A to 1C are process diagrams for producing an electronic element device using the electronic element encapsulating sheet which is one embodiment of the encapsulating sheet of the present invention, and FIG. 1A is the electronic element encapsulating sheet. and a step of preparing an electronic element mounting substrate, FIG. 1B shows a pressing step of bringing the electronic element encapsulating sheet into close contact with the electronic element, and FIG. 1C shows a heating step of heating the electronic element encapsulating sheet. 2A and 2B are diagrams for explaining the steps of preparing the electronic element encapsulating sheet and the electronic element mounting substrate in the encapsulation test, where FIG. 2A is a plan view and FIG. 2B is a cross-sectional view. FIGS. 3A and 3B are diagrams for explaining the press test step in the sealing test following FIGS. 2A and 2B, with FIG. 3A showing a plan view and FIG. 3B showing a cross-sectional view. FIGS. 4A and 4B are diagrams for explaining the heating test process in the sealing test, continuing from FIGS. 3A and 3B, with FIG. 4A showing a plan view and FIG. 4B showing a cross-sectional view. FIG. 5 shows a plan view of a variation of the heat test process shown in FIG. 4A.

An electronic element encapsulation sheet, which is one embodiment of the encapsulation sheet of the present invention, will be described with reference to FIGS. 1A to 4B.

In addition, in FIG. 3A and FIG. 4A, the electronic element 4 described later is not visible in plan view, but in order to clearly show its shape and arrangement, the electronic element sealing sheet 1 and the sealing layer A contact surface of the electronic element 4 to the substrate 2 is drawn by hatching so that the electronic element 4 is transparent.

As shown in FIGS. 1A to 1C, this electronic element sealing sheet 1 is used for manufacturing an electronic element device (electronic element package) 8. FIG. As shown in FIG. 1C, the electronic device device 8 comprises a substrate 2, an electronic device 4 and an encapsulation layer 5, which will be described later.

Further, the electronic element sealing sheet 1 shown in FIG. 1A is not the sealing layer 5 after sealing the electronic element 4 (see FIG. 1C), that is, before sealing the electronic element 4, and It is a precursor sheet for forming the stopping layer 5 .

As shown in FIG. 1A, the electronic element encapsulating sheet 1 has a substantially plate shape (film shape) extending in a direction (plane direction) perpendicular to the thickness direction. The electronic element encapsulating sheet 1 has a first surface 6 that is the other surface in the thickness direction and a second surface 7 that is the one surface in the thickness direction. The first surface 6 and the second surface 7 are planes (flat surfaces) parallel to each other.

The second surface 7, which will be described later, is an element contact surface that contacts at least one thickness direction surface 9 (described later) of the electronic element 4 when the electronic element sealing sheet 1 seals the electronic element 4. . The second surface 7 is also a substrate contact surface that contacts the one thickness direction surface 3 of the substrate 2 that does not face the electronic element 4 when the electronic element sealing sheet 1 seals the electronic element 4 .

When the electronic element sealing sheet 1 seals the electronic element 4 (see FIG. 1B), for example, the first surface 6 maintains its flat (planar) shape and the thickness of the second surface 7 The spacing in the direction is ensured to give the desired thickness.

The material of the electronic element encapsulating sheet 1 is not particularly limited as long as the viscosity described later and the maximum length L measured in the sealing test described later are within the ranges described later. Examples of the material of the sheet 1 for encapsulating electronic elements include encapsulating compositions.

The encapsulating composition contains, for example, a thermosetting component.

The thermosetting component is a component that is once softened by heating when the electronic element 4 is sealed, melts and flows, and is cured by further heating.

Moreover, the thermosetting component is in the B stage and not in the C stage in the sheet 1 for encapsulating electronic elements (that is, it is in a state before complete curing). In the B stage, the thermosetting component is in a state between the A stage in which it is liquid and the C stage in which it is completely cured. is smaller than

Thermosetting components include, for example, a main agent, a curing agent and a curing accelerator.

Examples of base resins include epoxy resins, phenol resins, melamine resins, vinyl ester resins, cyano ester resins, maleimide resins, and silicone resins. From the viewpoint of heat resistance and the like, the main agent is preferably an epoxy resin. If the main agent is an epoxy resin, the thermosetting component constitutes an epoxy thermosetting component together with a curing agent (epoxy curing agent) and a curing accelerator (epoxy curing accelerator), which will be described later.

Examples of epoxy resins include bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, modified bisphenol A type epoxy resin, modified bisphenol F type epoxy resin, biphenyl type epoxy resin, and phenol novolac type epoxy resin. trifunctional or higher polyfunctional epoxy resins such as resins, cresol novolak-type epoxy resins, trishydroxyphenylmethane-type epoxy resins, tetraphenylolethane-type epoxy resins, and dicyclopentadiene-type epoxy resins. These epoxy resins can be used alone or in combination of two or more.

Preferably, bifunctional epoxy resins are used alone, and more preferably, bisphenol A type epoxy resins and bisphenol F type epoxy resins are used.

The epoxy equivalent of the epoxy resin is, for example, 10 g/eq. above, preferably 100 g/eq. or more, and, for example, 300 g/eq. Below, preferably 250 g/eq. It is below.

The softening point of the main agent (preferably epoxy resin) is, for example, 50° C. or higher, preferably 70° C. or higher, and is, for example, 110° C. or lower, preferably 90° C. or lower.

The proportion of the main agent (preferably epoxy resin) in the sealing composition is, for example, 1% by mass or more, preferably 2% by mass or more, and is, for example, 30% by mass or less, preferably 10% by mass. It is below. The proportion of the main agent (preferably epoxy resin) in the thermosetting component is, for example, 50% by mass or more, preferably 60% by mass or more, and is, for example, 90% by mass or less, preferably 10% by mass. % by mass or less.

The ratio of the bifunctional epoxy resin (specifically, at least any one bifunctional epoxy resin selected from the group consisting of) in the sealing composition is, for example, 1% by mass or more, preferably 2% by mass More preferably, it is 3% by mass or more and, for example, 5% by mass or less. If the ratio of the above-described bifunctional epoxy resin is at least the above-described lower limit, the fluidity of the sealing composition can be improved, and the electronic element 4 can be reliably embedded.

The curing agent is a component (preferably epoxy resin curing agent) that cures the main agent by heating. Examples of curing agents include phenolic resins such as phenolic novolac resins.

If the main agent is an epoxy resin and the curing agent is a phenolic resin, the ratio of the curing agent is such that the total amount of hydroxyl groups in the phenolic resin is, for example, 0.7 equivalents or more per equivalent of the epoxy groups in the epoxy resin. , preferably 0.9 equivalents or more, for example, 1.5 equivalents or less, preferably 1.2 equivalents or less. Specifically, the number of parts of the curing agent is, for example, 30 parts by mass or more, preferably 50 parts by mass or more, and for example, 75 parts by mass or less, preferably 60 parts by mass, with respect to 100 parts by mass of the main agent. Part by mass or less.

The curing accelerator is a catalyst (thermosetting catalyst) (preferably an epoxy resin curing accelerator) that accelerates the curing of the main agent by heating, and is, for example, an organic phosphorus compound such as 2-phenyl-4,5 -Imidazole compounds such as dihydroxymethylimidazole (2PHZ-PW). Imidazole compounds are preferred. The amount of the curing accelerator compounded is, for example, 0.05 parts by mass or more and, for example, 5 parts by mass or less with respect to 100 parts by mass of the main agent.

The encapsulating composition can contain additives such as inorganic fillers, thermoplastic components, pigments, and silane coupling agents in addition to the thermosetting components described above.

The inorganic filler is an inorganic particle that improves the strength of the sealing layer 5 (described later) and imparts excellent toughness to the sealing layer 5 . Examples of inorganic filler materials include inorganic compounds such as quartz glass, talc, silica, alumina, aluminum nitride, silicon nitride, and boron nitride. These can be used singly or in combination of two or more. Silica is preferred.

The shape of the inorganic filler is not particularly limited, and examples thereof include a substantially spherical shape, a substantially plate shape, a substantially needle shape, and an irregular shape. A substantially spherical shape is preferred.

The average maximum length of the inorganic filler (average particle diameter in the case of a substantially spherical shape) M is, for example, 50 μm or less, preferably 20 μm or less, more preferably 10 μm or less. It is 1 μm or more, preferably 0.5 μm or more. The average particle diameter M is obtained as a D50 value (cumulative 50% median diameter) based on a particle size distribution determined by a particle size distribution measurement method in laser scattering, for example.

In addition, the inorganic filler may include a first filler and a second filler having an average maximum length M2 smaller than the average maximum length M1 of the first filler.

The average maximum length of the first filler (average particle diameter in the case of a substantially spherical shape) M1 is, for example, 1 μm or more, preferably 3 μm or more, and is, for example, 50 μm or less, preferably 30 μm or less. is.

The average maximum length of the second filler (average particle size in the case of a substantially spherical shape) M2 is, for example, less than 1 μm, preferably 0.8 μm or less, and, for example, 0.01 μm or more, preferably is 0.1 μm or more.

The ratio (M1/M2) of the average maximum length of the first filler to the average maximum length of the second filler (M1/M2) is, for example, 2 or more, preferably 5 or more, and, for example, 50 or less. , preferably 20 or less.

The materials of the first filler and the second filler may be the same or different.

Furthermore, the surface of the inorganic filler may be partially or wholly treated with a silane coupling agent or the like.

When the inorganic filler contains the first filler and the second filler described above, the proportion of the first filler in the sealing composition is, for example, 40% by mass or more, preferably more than 50% by mass, and , for example, 80% by mass or less, preferably 70% by mass or less. The amount of the second filler compounded is, for example, 40 parts by mass or more, preferably 50 parts by mass or more, and for example, 70 parts by mass or less, preferably 60 parts by mass, with respect to 100 parts by mass of the first filler. It is below.

The proportion of the inorganic filler in the sealing composition is, for example, 50% by mass or more, preferably 65% by mass or more, more preferably 80% by mass or more, and for example, 95% by mass or less, preferably It is 90% by mass or less. If the content ratio of the inorganic filler is at least the lower limit described above, the reliability of the resulting sealing layer 5 can be improved.

The thermoplastic component is a component that improves the flexibility of the electronic element sealing sheet 1 when the electronic element 4 is sealed. A thermoplastic component is, for example, a thermoplastic resin.

Examples of thermoplastic resins include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, Thermoplastic polyimide resin, polyamide resin (6-nylon, 6,6-nylon, etc.), phenoxy resin, acrylic resin, saturated polyester resin (PET, etc.), polyamideimide resin, fluorine resin, styrene-isobutylene-styrene block copolymer etc. These thermoplastic resins can be used alone or in combination of two or more.

The thermoplastic resin is preferably an acrylic resin from the viewpoint of improving dispersibility with the main agent (preferably epoxy resin).

As the acrylic resin, for example, a carboxyl group-containing (meta ) acrylic acid ester copolymers (preferably carboxyl group-containing acrylic acid ester copolymers), and the like.

Examples of alkyl groups include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, pentyl and hexyl.

Examples of other monomers include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid.

The weight average molecular weight of the thermoplastic component is, for example, 100,000 or more, preferably 300,000 or more, and is, for example, 1,000,000 or less, preferably 900,000 or less. The weight average molecular weight is measured by gel permeation chromatography (GPC) based on standard polystyrene conversion values.

The ratio of the thermoplastic component (solid content ratio) is adjusted so as not to hinder the thermosetting of the sealing composition. is 2% by mass or more, and is, for example, 10% by mass or less, preferably 5% by mass or less. In addition, the thermoplastic component may be prepared by being diluted with an appropriate solvent.

In addition, the ratio of the mass of the thermoplastic component to the mass of the inorganic filler (mass of the thermoplastic component/mass of the inorganic filler) is, for example, 0.175 or more, preferably 0.18 or more. It is 0.33 or less, preferably 0.30 or less, more preferably 0.25 or less. If the above-described ratio is at least the above-described lower limit, the later-described viscosity of the electronic element encapsulating sheet 1 can be set within a desired range. If the above-described proportion is equal to or less than the above-described upper limit, the later-described length L of the electronic element encapsulating sheet 1 can be set within a desired range.

Pigments include, for example, black pigments such as carbon black. The average particle size of the pigment is, for example, 0.001 μm or more and, for example, 1 μm or less. The proportion of the pigment is, for example, 0.1% by mass or more and, for example, 2% by mass or less, relative to the sealing composition.

Silane coupling agents include, for example, silane coupling agents containing epoxy groups. Silane coupling agents containing an epoxy group include, for example, 3-glycidoxydialkyldialkoxysilanes such as 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane; 3-glycidoxyalkyltrialkoxysilanes such as glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. Preferred is 3-glycidoxyalkyltrialkoxysilane. The mixing ratio of the silane coupling agent is, for example, 0.1 parts by mass or more, preferably 1 part by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass, with respect to 100 parts by mass of the inorganic filler. Part by mass or less.

The thickness of the electronic element encapsulating sheet 1 is not particularly limited, and is, for example, 50 μm or more and, for example, 2000 μm or less.

The shape of the electronic element encapsulating sheet 1 in the orthogonal direction (plane direction) is not particularly limited, and the size of the electronic element encapsulating sheet 1 is such that the plurality of electronic elements 4 are embedded (sealed) and exposed from the plurality of electronic elements 4. It is set so that it can come into contact with one surface 3 of the substrate 2 in the thickness direction. Specifically, the maximum length in the surface direction of the electronic element encapsulating sheet 1 is, for example, 1 mm or more and, for example, 100 mm or less.

The viscosity at 90° C. of the electronic element sealing sheet 1 is 5 kPa·s or more, preferably 10 kPa·s or more, more preferably 15 kPa·s or more, and still more preferably 25 kPa·s . Above all, it is particularly preferably 40 kPa·s or more, more preferably 50 kPa·s or more, further 75 kPa·s or more, furthermore 100 kPa·s or more. If the viscosity of the electronic element encapsulating sheet 1 at 90 ° C. is less than the above lower limit, when the electronic element encapsulating sheet 1 is heated to seal the electronic element 4, the electronic element encapsulating sheet 1 The material softens excessively, that is, excessive flow cannot be suppressed, and the material of the electronic element encapsulating sheet 1 protrudes outward. If it does so, the circumference|surroundings of the sheet|seat 1 for electronic element sealing will be contaminated.

On the other hand, the viscosity at 90° C. of the electronic element sealing sheet 1 is, for example, 500 kPa·s or less, preferably 200 kPa·s or less, more preferably 100 kPa·s or less. If the viscosity of the electronic element encapsulating sheet 1 is equal to or less than the upper limit described above, the maximum length L measured in the encapsulation test described later can be reliably set within the range described later.

The temperature of 90° C. that determines the viscosity of the electronic element encapsulating sheet 1 is the temperature that indicates the lowest melt viscosity during heating, and when repeated measurements are performed for each of various electronic element encapsulating sheets 1 Secondly, it is the temperature at which the variation in viscosity becomes small.

A method for measuring the viscosity of the electronic element encapsulating sheet 1 will be described in detail in later Examples.

In the electronic element encapsulating sheet 1, the maximum length L of the second test gap 72 measured in the following encapsulation test is 150 μm or less. The maximum length L is preferably 125 μm or less, more preferably 100 μm or less, still more preferably less than 85 μm, particularly preferably 80 μm or less, further preferably 70 μm or less, 60 μm or less, 50 μm or less, and 25 μm or less. Yes, and is, for example, 1 μm or more.

<Sealing test>
In the sealing test, the following press test process (see FIGS. 2A to 3B) and heating test process (see FIGS. 4A and 4B) are performed in order.

In the press test step, first, as shown in FIGS. 2A and 2B , one side 53 in the thickness direction of a test substrate 52 made of glass is oriented in a first direction perpendicular to the thickness direction (horizontal direction in FIGS. 2A and 2B ) and , a rectangular test element having a length L1 of 10 mm and a thickness T1 of 400 μm in each of the thickness direction and the second direction perpendicular to the first direction (vertical direction in FIG. 2A and depth direction in FIG. 2B). Place one 54.

Next, a rectangular sealing test sheet 51 having a length L2 of 20 mm in each of the first and second directions and a thickness T2 of 260 μm was arranged so as to overlap the test element 54 in the thickness direction. , 25 ° C. and 1330 Pa for 10 seconds, and then under the same conditions (1330 Pa reduced pressure condition), as shown in FIG. The sheet 51 is pressed against the test element 54 to bring it into close contact.

In this press test step, the test sheet 51 for sealing electronic element sealing sheet 1 (see FIGS. 1A and 1B) has the size described above (each length L2 in the first direction and the second direction is 20 mm). ) is a test sheet that has been cut and processed. The sealing test sheet 51 is the electronic element sealing sheet 1 whose thickness is adjusted in advance so that the thickness T2 is 260 μm.

The press test process is performed in a decompression device (vacuum device) 60 . The conditions of the decompression device (vacuum device) 60 are 25° C. and 1330 Pa as described above.

As shown in FIGS. 3A and 3B, in this press test process, the end face 61 (peripheral side face 62) of the test element 54 in both the first direction and the second direction, and the thickness direction one face 53 of the test substrate 52 , and the other thickness direction surface 63 of the sealing layer 5 facing the end surface 61 and the one thickness direction surface 53 form a first test gap 71 . The first test gap 71 faces, for example, all of the four surfaces (four end surfaces 61 ) that are the peripheral side surfaces 62 of the test element 54 .

However, the four first test gaps 71 do not face the four corners 65 corresponding to the four end faces 61 . The four first test gaps 71 are partitioned (not communicated with each other) by the four corners 65 .

In the heating test step, as shown in FIGS. 4A and 4B , first, the electronic device mounting substrate 12 and the sealing test sheet 51 are taken out from the decompression device 60 . Then, the first test gap 71 (see FIGS. 3A and 3B) is in a reduced pressure (vacuum) state, while the outside of the sealing test sheet 51 is at atmospheric pressure. The sealing test sheet 51 is pressed by the atmospheric pressure so as to approach . That is, the portion of the sealing sheet facing the first test gap 71 is pressed so that the volume of the first test gap 71 is reduced (the first test gap 71 is reduced). Subsequently, the sealing layer 5 is formed by heating at 150° C. for 1 hour. Specifically, if the sealing test sheet 51 is in the B stage containing a thermosetting component, the sealing test sheet 51 is heated to thermally cure (completely cure, C stage). Then, the sealing test sheet 51 is once softened and has fluidity. Then, the pressing described above forms the second test gap 72 having a volume smaller than that of the first test gap 71 .

The second test gap 72 is also defined by the peripheral side surfaces 61 (four end surfaces 62 ) of the test element 54 , one thickness direction surface 53 of the test substrate 52 , and the other thickness direction surface 63 of the sealing layer 5 . Similarly to the first test gap 71, the second test gap 72 is also partitioned by the four corners 65 (not communicating with each other).

Then, the length (maximum length) of the second test gap 72 to the farthest position from the test element 54 is obtained as the width L. FIG. When the sizes of the plurality of second test gaps 72 are different, the width L of the largest second test gap 72 is obtained.

Four second test gaps 72 are formed corresponding to the four end surfaces 61 . The four end faces 61 are composed of a first direction one end face 81 (for example, the left face in FIG. 4A) and a first direction other end face 82 (for example, the right face in FIG. 4A) facing each other in the first direction, and facing each other in the second direction. A second direction one end surface 83 (eg, the upper surface in FIG. 4A) and a second direction other end surface 84 (eg, the lower surface in FIG. 4A).

The maximum length in the first direction facing the first direction one end face 81 is width L3, and the maximum length in the first direction facing the first direction other end face 82 is width L4. be. The maximum length in the second direction facing the second direction one end face 83 is width L5, and the maximum length in the second direction facing the second direction other end face 84 is width L6. be.

The second test gap 72 corresponding to the first direction one end face 81 and/or the first direction other end face 82 extends from the second direction end portion of the first direction one end face 81 and/or the first direction other end face 82 to the second test gap 72 . The width increases toward the central portion in the two directions, and has width L3 and/or width L4 in the central portion in the second direction. The second test gap 72 corresponding to the second direction one end face 83 and/or the second direction other end face 84 is formed from the first direction end of the second direction one end face 83 and/or the second direction other end face 84 to the first direction. The width increases toward the central portion, and has width L5 and/or width L6 at the central portion in the first direction.

Then, the maximum value of the widths L3 to L6 is obtained as L. Specifically, the width L3 and the width L4 are compared, and if the width L3 is the same as or longer than the width L4, the width L3 is obtained as the width L as the maximum length of the second test gap. Also, the width L3 and the width L5 are compared, and if the width L3 is the same as or longer than the width L5, the width L3 is obtained as the width L as the maximum length of the second test gap. The comparison between the width L3 and the width L6, the width L4 and the width L5, and the width L4 and the width L6 is the same as described above, and the details are omitted.

When the maximum length (width) L of the second test gap 72 exceeds the upper limit described above, the size of the second gap 17, which will be described later, becomes larger, so that fine unevenness is followed and uniform (homogeneous) (clean). The reliability of the resulting electronic element device 8 is lowered.

In order to manufacture the sheet 1 for electronic element encapsulation, first, a sealing composition is prepared. Specifically, the components described above are blended and mixed to prepare a sealing composition. Preferably, the varnish is prepared by blending and mixing the above components (and solvent if necessary). Thereafter, the varnish is applied to a release sheet (not shown) and dried to obtain the electronic element encapsulating sheet 1 . In this case, the electronic element encapsulating sheet 1 is obtained while being supported by a release sheet (not shown).

On the other hand, the electronic element encapsulating sheet 1 can also be formed from the encapsulating composition by kneading extrusion without preparing the varnish.

In the sheet 1 for electronic element sealing, the sheet 1 for electronic element sealing is B stage, for example, when it contains a thermosetting component.

(Manufacturing method of electronic element device)
Next, a method for manufacturing an electronic element device 8 using the electronic element encapsulating sheet 1 will be described with reference to FIGS. 1A to 1C.

This method includes a preparation step (see FIG. 1A) of preparing the electronic element sealing sheet 1 and the electronic element 4, and sealing the electronic element 4 using the electronic element sealing sheet 1, sealing A sealing step (see FIGS. 1B and 1C) is provided to form layer 5 .

(Preparation process)
As shown in FIG. 1A, in the preparation step, the electronic element encapsulating sheet 1 described above (preferably, B-stage electronic element encapsulating sheet 1) is prepared. Separately, in a preparation step, the electronic element 4 mounted on the substrate 2 is prepared.

A plurality of electronic elements 4 are arranged on one surface of the substrate 2 at intervals. Each of the plurality of electronic elements 4 has a substantially flat plate shape extending in the plane direction. Specifically, the electronic element 4 has a thickness direction one surface 9, a thickness direction other surface 10, and a peripheral side surface 11, which is an orthogonal direction end surface, continuously.

One thickness direction surface 9 and the other thickness direction surface 10 are planes parallel to each other. The peripheral side surface 11 connects the peripheral edges of the one thickness direction surface 9 and the other thickness direction surface 10 in the thickness direction.

The electronic element 4 is not particularly limited, and includes various electronic elements such as hollow electronic elements and semiconductor elements. A plurality of electronic elements 4 are mounted so as to face one surface 3 in the thickness direction of the substrate 2 . The plurality of electronic elements 4 are flip-chip mounted on the substrate 2, for example. A plurality of electronic elements 4 are arranged on one surface 3 in the thickness direction of the substrate 2 at intervals.

The thickness of the electronic element 4 is, for example, 50 μm or more and, for example, 500 μm or less. Note that the thicknesses of the plurality of electronic elements 4 may be the same or different.

When the thicknesses of the plurality of electronic elements 4 are different from each other, the thickness direction positions of the first surfaces 9 of the electronic elements 4 are shifted. In this case, among the plurality of one thickness direction surfaces 9, the distance D1 in the thickness direction between the one thickness direction surface 9 located on the other side in the thickness direction and the one thickness direction surface 9 located on the one side in the thickness direction is , for example, 20 μm or more, further 50 μm or more, and for example, 5000 μm or less, further 1000 μm or less.

The maximum length in the plane direction of the electronic element 4 is, for example, 1000 μm or more and, for example, 3000 μm or less. The distance D2 between the electronic elements 4 adjacent to each other (adjacent distance of the peripheral side surfaces 11) is, for example, 5000 μm or less, preferably 2000 μm or less, and is, for example, 100 μm or more, preferably 500 μm or more.

The substrate 2 is provided on the electronic device mounting substrate 12 together with the electronic device 4 . That is, the electronic element mounting substrate 12 includes the electronic element 4 and the substrate 2 on which the electronic element 4 is mounted.

The substrate 2 has a substantially flat plate shape extending in the plane direction. The substrate 2 has a size surrounding the plurality of electronic elements 4 in plan view. The substrate 2 has one thickness direction surface 3 and the other thickness direction surface 13 .

The one thickness direction surface 3 is a flat surface exposed on one side in the thickness direction. The other thickness direction surface 13 is a plane parallel to the one thickness direction surface 3 . The material of the substrate 2 is not particularly limited, and examples thereof include resins, ceramics, and metals. The thickness of the substrate 2 is not particularly limited, and is, for example, 10 μm or more, preferably 1000 μm or less.

(sealing process)
In the encapsulation step, as shown in FIGS. 1B and 1C, the electronic element encapsulation sheet 1 is then used to enclose the electronic element 4 . Specifically, the sealing step includes a pressing step (see FIG. 1B) and a heating step (see FIG. 1C). A pressing process and a heating process are implemented in order.

The conditions for the pressing step and the heating step can include the conditions (temperature, time, pressure, etc.) for the pressing test step and the heating test step in the sealing test described above. The pressing process and the heating process will be described in order below.

(Pressing process)
As shown by the arrow in FIG. 1A and FIG. 1B, in the pressing step, first, the electronic element is pressed so that the second surface 7 of the electronic element encapsulating sheet 1 is in contact with the thickness direction one surface 9 of the plurality of electronic elements 4 . The sheet|seat 1 for sealing is orient|assigned to the thickness direction other side, and is pressurized using a press (not shown) in a decompression device (specifically, in the vacuum device 60), for example. If necessary, the electronic element encapsulating sheet 1 is heated at the same time. At this time, the electronic element encapsulating sheet 1 is plastically deformed according to the outer shape of the electronic element 4 . The degree of vacuum, pressure, temperature and the like are not particularly limited.

Thereby, the electronic element encapsulating sheet 1 covers the plurality of electronic elements 4 . In other words, a plurality of electronic elements 4 are partially embedded in one electronic element encapsulating sheet 1 . At the same time, the second surface 7 of the electronic element encapsulating sheet 1 contacts the one surface 3 in the thickness direction of the substrate 2 around the electronic element 4 .

Then, as shown in FIGS. 3A and 3B, a first gap 14 having the same (or similar) shape and arrangement as the first test gap 71 in the sealing test is formed. The first gap 14 is formed between the peripheral side surface 11 of the electronic element 4, the one thickness direction surface 3 of the substrate 2, and the second surface 7 of the electronic element sealing sheet 1 facing the peripheral side surface 11 and the one thickness direction surface 3. are separated by

In addition, the first gap 14 is blocked by the electronic element encapsulating sheet 1 , that is, does not communicate with the outside (that is, the atmosphere inside the vacuum device 60 ).

In addition, the sheet|seat 1 for electronic element sealing is still B stage, for example, when containing a thermosetting component.

(Heating process)
Thereafter, as shown in FIG. 1C, the electronic element mounting substrate 12 and the electronic element encapsulating sheet 1 are taken out from the vacuum device 60, placed under atmospheric pressure, and heated. Specifically, when the electronic element encapsulating sheet 1 is in the B stage containing a thermosetting component, it is thermally cured (to C stage, complete curing) by the above-described heating. Thereby, the sealing layer 5 is formed. That is, the encapsulating layer 5 is prepared from the electronic element encapsulating sheet 1 .

The sealing layer 5 has a thickness direction one surface 15 and a thickness direction other surface 16 . One thickness direction surface 15 is formed from the first surface 6 (see FIG. 1A) of the electronic element encapsulating sheet 1 . The other thickness direction surface 16 is formed from the second surface 7 (see FIG. 1A) of the electronic element encapsulating sheet 1 .

In this heating step, a second gap 17 is formed by making the first gap 14 smaller.

Specifically, the above-described heating increases the fluidity of the electronic element encapsulating sheet 1, and the air pressure in the first gap 14 is lower than the air pressure outside (that is, negative pressure). Therefore, a second gap 17 is formed by making the first gap 14 smaller.

This second gap 17 is defined by the peripheral side surface 11 of the electronic element 4 , the one thickness direction surface 3 of the substrate 2 , and the other thickness direction surface 13 of the sealing layer 5 facing the peripheral side surface 11 and the one thickness direction surface 3 . partitioned.

The material of the sealing layer 5 is, for example, a cured product (C-stage material) of the material of the electronic element sealing sheet 1 .

The linear expansion coefficient α of the sealing layer 5 is, for example, 100 ppm/°C or less, preferably 20 ppm/°C or less, more preferably 15 ppm/°C or less, and for example, 1 ppm/°C or more. be. If the linear expansion coefficient α of the sealing layer 5 is equal to or less than the upper limit described above, the difference from the linear expansion coefficient α of the electronic element 4 becomes small, and the difference in volume change between the sealing layer 5 and the electronic element 4 with respect to thermal history. becomes smaller, it is possible to obtain an electronic element device 8 with excellent reliability.

As a result, the electronic element device 8 including the electronic element mounting substrate 12 and the cured layer 5 is obtained. Further, the electronic element device 8 has the second gap 17 described above.

The maximum distance L6 between the second gap 17 and the peripheral side surface 11 of the electronic element 4 is, for example, 150 μm or less, preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 1 μm or less. The method for obtaining the maximum value of the separation distance L6 of the second gap 17 is the same as the method for obtaining the maximum length L of the second test gap 72 described above.

Since the electronic element encapsulating sheet 1 has a viscosity at 90° C. of 5 kPa·s or more, when the electronic element encapsulating sheet 1 is heated to seal the electronic element 4, the electronic element The sheet 1 for sealing is softened, suppresses excessive flow, and can reliably embed the electronic element 4 while suppressing the protrusion of the material of the sheet 1 for sealing the electronic element. Therefore, the electronic element encapsulating sheet 1 can suppress contamination to the surroundings while having excellent sealing properties for the electronic element 4 .

On the other hand, the electronic element encapsulating sheet 1 has a short maximum length L of 150 μm or less, which is measured in the encapsulation test. Therefore, it is possible to manufacture an electronic element device 8 with excellent reliability. can do.

Therefore, according to this electronic element encapsulating sheet 1, the electronic element 4 can be reliably sealed while suppressing the protrusion of the material of the electronic element encapsulating sheet 1, and an electronic element device 8 having excellent reliability can be manufactured. can do.

In the method for manufacturing the electronic element device 8, the viscosity of the electronic element encapsulating sheet 1 at 90° C. is 5 kPa·s or more, so the electronic element encapsulating sheet 1 is heated to seal the electronic element 4. At that time, the electronic element encapsulating sheet 1 is softened, suppresses excessive flow, suppresses the protrusion of the material of the electronic element encapsulating sheet 1, and reliably embeds the electronic element 4. can be done. Therefore, the electronic element encapsulating sheet 1 can suppress contamination to the surroundings while having excellent sealing properties for the electronic element 4 .

On the other hand, the electronic element encapsulating sheet 1 has a short width L of 150 μm or less, which is the maximum length L measured in the encapsulation test. It is possible to manufacture an electronic element device 8 that is excellent in quality and, therefore, excellent in reliability.

Therefore, according to the method for manufacturing the electronic element device 8, the electronic element device 8 can be reliably sealed while suppressing the protrusion of the material of the electronic element sealing sheet 1, and the electronic element device 8 having excellent reliability is manufactured. can do.

The method for manufacturing the electronic element device 8 further includes a selection step of selecting non-defective sheets 1 for electronic element encapsulation that satisfy the criterion that the maximum length L measured in the above-described encapsulation test is 150 μm or less. can also

Modifications In each modification below, the same reference numerals are given to the same members and steps as in the above-described embodiment, and detailed description thereof will be omitted. Moreover, each modification can have the same effects as the one embodiment, unless otherwise specified. Furthermore, one embodiment and its modifications can be combined as appropriate.

In the above description, the pressing process is performed under vacuum (reduced pressure), but it is not limited to this, and can be performed under atmospheric pressure, for example. Preferably, the pressing step is performed under vacuum. If the pressing step is performed under vacuum, in the heating step after the pressing step, when placing the electronic element encapsulating sheet 1 under atmospheric pressure (returning the atmosphere of the electronic element encapsulating sheet 1 to atmospheric pressure), Based on the negative pressure described above, the separation distance L6 in the second gap 17 and thus the volume of the second gap 17 can be reduced. In addition, since the sealing test includes a press test step of pressing in a vacuum, it is possible to reliably obtain (select) non-defective electronic element devices 8 based on (refer to) the results of the sealing test. can.

As shown in phantom lines in FIG. 1C, the method can also include dicing the substrate 2 and encapsulation layer 5 around the electronic device 4 in the electronic device device 8 . For example, a dicing saw (not shown) is used to cut the substrate 2 and the sealing layer 5 along the first direction and the second direction while placing a dicing tape 70 indicated by a phantom line on the other thickness direction surface 13 of the substrate 2 . to cut. Thereby, the electronic element device 8 is singulated.

Also, in the sealing test, the first test gap 71 and the second test gap 72 were formed with respect to each of the four end surfaces 62. For example, although not shown, one, two, and three gaps were formed. can be either

Furthermore, as shown in FIG. 5 , the four first test gaps 71 may communicate with each other to form one large substantially circular annular shape including four corners 65 . In addition, even if the four second test gaps 72 communicate with each other and have one large, but smaller than the first test gap 71 , substantially annular shape in plan view so as to include four corners 65 . good.

In one embodiment, in the heating step, the electronic element encapsulating sheet 1 and the electronic element mounting substrate 12 are removed from the vacuum device 60. For example, air is injected into the vacuum device 60 without removing it from the vacuum device 60. You can also do (withdraw).

In one embodiment, the pressing and heating steps are performed sequentially, but they can be performed simultaneously, for example.

The electronic element encapsulating sheet 1 and the encapsulating layer 5 are both formed of a single layer, but they can also be formed of multiple layers, although not shown.

EXAMPLES Examples and comparative examples are shown below to describe the present invention more specifically. In addition, the present invention is not limited to Examples and Comparative Examples. In addition, specific numerical values such as the mixing ratio (content ratio), physical property values, and parameters used in the following description are the corresponding mixing ratios ( content ratio), physical properties, parameters, etc. can.

Components used in Examples and Comparative Examples are shown below.

Epoxy resin A: YSLV-80XY manufactured by Nippon Steel Chemical Co., Ltd. (bisphenol F type epoxy resin, epoxy equivalent 200 g / eq. softening point 80 ° C.)
Epoxy resin B: EPPN501-HY manufactured by Nippon Kayaku Co., Ltd. (epoxy equivalent 169 g / eq. softening point 60 ° C.)
Curing agent: LVR-8210DL manufactured by Gun Ei Kagaku Co., Ltd. (novolac type phenolic resin, epoxy resin curing agent, hydroxyl equivalent: 104 g/eq., softening point: 60 ° C.)
Acrylic resin: HME-2006M manufactured by Negami Kogyo Co., Ltd., carboxyl group-containing acrylic acid ester copolymer (acrylic polymer), weight average molecular weight: 600,000, glass transition temperature (Tg): -35 ° C., solid content concentration 20% by mass Methyl ethyl ketone solution Curing accelerator: Shikoku Kasei Co., Ltd. 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazole), epoxy resin curing accelerator Silane coupling agent: Shin-Etsu Chemical Co., Ltd. KBM-403 (3 -glycidoxypropyltrimethoxysilane)
Carbon black: #20 manufactured by Mitsubishi Chemical Corporation
First filler: FB-5SDC (spherical fused silica powder (inorganic filler), average particle size 5 μm)
Second filler: an inorganic filler obtained by surface-treating SC220G-SMJ (average particle size 0.5 μm) manufactured by Admatechs with 3-methacryloxypropyltrimethoxysilane (product name: KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). Surface-treated with 1 part by mass of a silane coupling agent with respect to 100 parts by mass of the inorganic filler.

Examples 1-5 and Comparative Examples 1-3
A sealing composition was prepared according to the formulation shown in Table 1, and an electronic element sealing sheet 1 having a thickness of 260 μm was produced from this sealing composition. The electronic element encapsulating sheet 1 was obtained in a state supported by a release sheet (not shown).

(evaluation)
The following items were evaluated. The results are listed in Table 1.

(Sealing test)
In the sealing test, as shown in FIGS. 2A to 4B, the above press test step and the above heating test step were performed in order.

As shown in FIGS. 2A and 2B, in the press test step, first, in the decompression device 60, a test substrate 52 made of a slide glass having a first direction length of 76 mm and a second direction length of 26 mm is pressed in the thickness direction. One square test element 54 having a length L1 of 10 mm and a thickness T1 of 400 μm was placed on one surface 53 . Next, a square sealing test sheet 51 having a length L2 of 20 mm was produced from the electronic element sealing sheet 1 having a thickness T2 of 260 μm. A release sheet (not shown) was also formed in a square shape together with the sealing test sheet 51 . Next, after placing the sealing test sheet 51 so as to overlap the test element 54 in the thickness direction, it was left for 10 seconds under the conditions of 25° C. and 1330 Pa, and then under the same conditions (1330 Pa reduced pressure conditions). 3B, the sealing test sheet 51 was pressed against the test element 54 by a flat plate press 55 at 2 MPa for 60 seconds so as to be in close contact.

As shown in FIGS. 4A and 4B, in the heating test step after the press test step, the electronic element mounting substrate 12 and the sealing test sheet 51 are taken out from the decompression device 60, then the release sheet is peeled off (removed), Thereafter, the sealing test sheet 51 was completely cured by heating at 150° C. for 1 hour to form the sealing layer 5 .

After that, the width (maximum length) L of the second test gap 72 was measured using a KEYENCE brand name “Digital Microscope”.

(viscosity)
The viscosity of the sheet 1 for encapsulating electronic elements at 90° C. was measured by a parallel plate method using a rheometer (MARS III manufactured by HAAKE). Specifically, the viscosity was measured three times under conditions of a gap of 0.8 mm, a parallel plate diameter of 8 mm, a frequency of 1 Hz, a strain of 0.05%, and an isothermal temperature of 90°C, and the average viscosity at 90°C was taken.

(Linear expansion coefficient α)
The electronic element sealing sheet 1 was heated at 150° C. for 1 hour to obtain a cured sheet (a cured sheet corresponding to the sealing layer 5). After that, a measurement sample having a length of 15 mm, a width of 4.5 mm, and a thickness of 300 μm was cut out from the cured product sheet. Subsequently, after setting the measurement sample on a tensile jig of a thermomechanical measurement device (manufactured by Rigaku: model TMA8310), in a temperature range of 25 to 260 ° C., a tensile load of 2 g and a heating rate of 5 ° C./min. Then, the coefficient of linear expansion α was calculated from the coefficient of expansion at 30°C to 50°C.

(protrusion)
The protrusion was evaluated according to the following criteria.
○: In the above sealing test, the protruding length of the sealing composition of the sealing test sheet 51 before heating at 150 ° C. from the peripheral edge of the release sheet in the sealing test sheet 51 after pressing The thickness (amount) was 300 µm or less.
×: In the above sealing test, the protruding length of the sealing composition of the sealing test sheet 51 before heating at 150 ° C. from the peripheral edge of the release sheet in the sealing test sheet 51 after pressing The thickness (amount) exceeded 300 μm.

1 electronic element sealing sheet 2 substrate 3 thickness direction one side (substrate)
5 sealing layer 51 sealing test sheet 52 test substrate 53 thickness direction one side (test substrate)
54 Test element 72 Second test gap L Maximum length (second test gap)

Claims (6)

A sealing sheet used to form a sealing layer that seals an electronic element mounted on one side in the thickness direction of the substrate,
90 ° C. viscosity is 5 kPa s or more,
A sealing sheet having a maximum length L of 150 μm or less as measured by the following sealing test.
<Sealing test>
A test substrate made of glass having a length of 10 mm and a thickness of 400 μm in each of a first direction orthogonal to the thickness direction and a second direction orthogonal to the thickness direction and the first direction was placed on one surface in the thickness direction of the test substrate. A certain rectangular test element is arranged, and under the conditions of 25° C. and 1330 Pa, the rectangular sealing sheet having a length of 20 mm in each of the first direction and the second direction and a thickness of 260 μm is prepared. , pressurized against the test element for 60 seconds at 2 MPa so as to overlap the test element in the thickness direction, and then heat the sealing sheet at 150 ° C. for 1 hour, forming the sealing layer; Facing at least one end surface of the test element in at least one of the first direction and the second direction, one surface in the thickness direction of the test substrate, and one surface in the thickness direction A test gap defined by the other side in the thickness direction of the sealing layer is formed, and the maximum length L of the test gap in the one direction is measured. The encapsulating sheet according to claim 1, wherein the viscosity at 90°C is 200 kPa·s or less. The encapsulating sheet according to claim 1 or 2, wherein the encapsulating layer has a linear expansion coefficient of 20 ppm/°C or less. The encapsulating sheet according to any one of claims 1 to 3, characterized by containing 80% by mass or more of an inorganic filler. Any one of claims 1 to 4, characterized by containing 2% by mass or more of at least one bifunctional epoxy resin selected from the group consisting of bisphenol A type epoxy resins and bisphenol F type epoxy resins. 1. The sealing sheet according to item 1. The sealing sheet according to any one of claims 1 to 5 is pressed against the electronic element and heated to form the sealing layer that seals the electronic element. A method for manufacturing an electronic element device.

Images