JP6997654B2 - Sealing sheet - Google Patents

Description

The present invention relates to a sealing sheet.

Conventionally, it is known that a semiconductor element encapsulation sheet is used for manufacturing a semiconductor package by encapsulating a semiconductor chip mounted on a substrate (see, for example, Patent Document 1).

For example, it has been proposed to heat-press a gel-like epoxy-based curable resin sheet while providing a gap between a substrate and a semiconductor chip (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-19714

However, in the method described in Patent Document 1, a semiconductor chip mounted on a substrate and a gel-like epoxy-based curable resin sheet supported by a release sheet having the same size are laminated and pressed. They are placed on the lower plate and then hot-pressed on the upper plate against the lower plate, but the gel-like epoxy curable resin sheet goes beyond the peripheral edge of the substrate and falls to the surface of the lower plate. May adhere to. In addition, the gel-like epoxy-based curable resin sheet may jump far beyond the peripheral edge of the release sheet and adhere to the upper plate.

In this case, it is necessary to clean the lower plate and the upper plate of the press each time, and there is a problem that the yield in the manufacture of the semiconductor package is lowered.

The present invention provides a sealing sheet capable of reliably encapsulating a semiconductor element and efficiently manufacturing a semiconductor element device while suppressing contamination of surrounding members.

The present invention (1) contains an epoxy resin, a novolak-type phenol resin, and a thermoplastic resin containing a carboxyl group, and the protrusion length L1 measured by the following method is 3 mm or less. Includes sheets for.

The sealing sheet having a thickness of 260 μm, a length of 5 cm, and a width of 5 cm is supported by a release sheet having the same length and width as the sealing sheet, and the alumina plate 7 having a length of 6 cm and a width of 6 cm is supported. The alumina plate, the sealing sheet, and the release sheet are arranged on one side in the thickness direction so as to be arranged in order on one side in the thickness direction, and they are placed at 70 ° C. for 60 seconds with a force of 360 N to have the thickness. It is hot-pressed in the direction, and then the protrusion length L1 of the sealing sheet from the release sheet to the outside in the direction orthogonal to the thickness direction is measured.

The present invention (2) includes the sealing sheet according to (1), wherein the acid value of the thermoplastic resin is 10 mgKOH / g or more and 40 mgKOH / g or less.

The present invention (3) includes the sealing sheet according to (1) or (2), wherein the glass transition temperature of the thermoplastic resin is −20 ° C. or higher and 10 ° C. or lower.

In the present invention (4), the number of parts to be blended with respect to 100 parts by mass of the total amount of the epoxy resin and the novolak type phenol resin of the thermoplastic resin is 10 parts by mass or more and 90 parts by mass or less (1) to (3). The sealing sheet according to any one of the above is included.

The present invention (5) further contains the first inorganic particles and the second inorganic particles having an average particle size smaller than the average particle size of the first inorganic particles, and the first inorganic particles of the second inorganic particles. The sealing sheet according to any one of (1) to (4), wherein the number of parts to be blended with respect to 100 parts by mass of the particles is 50 parts by mass or more and less than 100 parts by mass.

The present invention (6) includes the sealing sheet according to any one of (1) to (5), wherein the reaction rate R obtained by the following method is 50% or more.

The differential scanning calorimetry of the sealing sheet 1 is measured under the following conditions to obtain a first calorific value H1.

Measurement temperature range: 0 to 300 ° C
Temperature rise rate: 10 ° C / min Measured mass: 15 mg
Separately, the sealing sheet is heated at 150 ° C. for 10 minutes, and the sealing sheet is measured for differential scanning calorimetry under the above conditions to obtain a second calorific value H2.

Then, the reaction rate is the percentage ([H1-H2] / H1 × 100%) of the calorific value [H1-H2] obtained by subtracting the second calorific value H2 from the first calorific value H1 with respect to the first calorific value H1. Obtained as R.

Since the sealing sheet of the present invention has a protrusion length L1 measured by the above method of 3 mm or less, the semiconductor element is reliably sealed while suppressing the surrounding members from being contaminated by the sealing sheet. It can be stopped and the semiconductor device can be efficiently manufactured.

FIG. 1 shows a cross-sectional view of a semiconductor device encapsulation sheet according to an embodiment of the encapsulation sheet of the present invention. 2A and 2B are diagrams illustrating a method of measuring the protrusion length of the semiconductor device encapsulation sheet shown in FIG. 1, and FIG. 2A is a step of arranging the semiconductor element encapsulation sheet on an alumina plate. FIG. 2B shows a step of hot-pressing a semiconductor device encapsulation sheet and measuring the protrusion length. 3A to 3B show process diagrams of a method of sealing a semiconductor element using the semiconductor element encapsulating sheet shown in FIG. 1 to manufacture a semiconductor element package, and FIG. 2A shows the semiconductor element encapsulation. A step of arranging the sheet for facing the semiconductor element and the substrate, FIG. 2B shows a step of sealing the semiconductor element with the sheet for sealing the semiconductor element.

The semiconductor device encapsulation sheet according to the embodiment of the encapsulation sheet of the present invention will be described with reference to FIGS. 1 to 3B.

The semiconductor element encapsulation sheet 1 is a encapsulation sheet for encapsulating the semiconductor element 3 mounted on the substrate 2.

Further, the semiconductor element encapsulation sheet 1 is a component for manufacturing a semiconductor element package 5 (an example of a semiconductor element device) described later, and the semiconductor element encapsulation sheet 1 is not the semiconductor element package 5 itself, but the semiconductor element encapsulation sheet 1. , The semiconductor element 3 and the substrate 2 on which the semiconductor element 3 is mounted are not included, and specifically, the device is distributed as a single component and can be industrially used.

The semiconductor element encapsulation sheet 1 is not a cured sheet 20 (FIGS. 3B and 3C) after encapsulating the semiconductor element 3, that is, a sheet before encapsulating the semiconductor element 3.

The semiconductor element encapsulation sheet 1 has a substantially plate shape (film shape) extending in a direction (plane direction) orthogonal to the thickness direction. Further, the semiconductor element encapsulation sheet 1 has a flat one surface (upper surface) 16 in the thickness direction, a flat other surface (lower surface) 17 in the thickness direction, and a first peripheral surface (connecting surface) connecting the peripheral edges thereof. Alternatively, the peripheral side surface) 6 is provided. The first peripheral surface 6 is a peripheral surface including the peripheral edge of the semiconductor element encapsulating sheet 1.

The material of the semiconductor device encapsulation sheet 1 is an epoxy-based encapsulation composition (epoxy-based thermosetting composition) that flows once, softens, and then cures by heating. The epoxy-based sealing composition contains an epoxy resin, a novolak-type phenol resin, and a thermoplastic resin containing a carboxyl group.

The epoxy resin is a main agent in an epoxy-based sealing composition, and is, for example, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a modified bisphenol A type epoxy resin, a modified bisphenol F type epoxy resin, a biphenyl type epoxy resin, or the like. Bifunctional epoxy resin, for example, trifunctional or higher functional epoxy such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, trishydroxyphenylmethane type epoxy resin, tetraphenylol ethane type epoxy resin, dicyclopentadiene type epoxy resin, etc. Examples include resin. These epoxy resins can be used alone or in combination of two or more.

Preferably, the bifunctional epoxy resin is used alone, and specifically, the bisphenol F type epoxy resin is used alone.

The epoxy equivalent of the epoxy resin is, for example, 10 g / eq. As mentioned above, preferably 100 g / eq. The above, and for example, 300 g / eq. Hereinafter, preferably 250 g / eq. It is as follows.

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

The proportion of the epoxy resin in the epoxy-based sealing composition is, for example, 1% by mass or more, preferably 2% by mass or more, and for example, 30% by mass or less, preferably 10% by mass or less.

The novolak type phenol resin has a hydroxyl group and is an epoxy resin curing agent (epoxy resin curing agent).

The softening point of the novolak type phenol resin is, for example, 40 ° C. or higher, preferably 50 ° C. or higher, and for example, 90 ° C. or lower, preferably 70 ° C. or lower. Further, the difference between the softening point of the novolak type phenol resin and the softening point of the epoxy resin is relatively small, specifically, for example, 40 ° C. or lower, preferably 30 ° C. or lower, more preferably 20 ° C. or lower. Is.

The hydroxyl group equivalent of the novolak type phenol resin is, for example, 10 g / eq. As mentioned above, preferably 50 g / eq. The above, and for example, 300 g / eq. Hereinafter, preferably, 150 g / eq. It is as follows.

As for the number of copies of the novolak-type phenol resin, the total number of hydroxyl groups in the novolak-type phenol resin is, for example, 0.7 equivalent or more, preferably 0.9 equivalent or more, for example, with respect to 1 equivalent of the epoxy group in the epoxy resin. , 1.5 equivalents or less, preferably 1.2 equivalents or less. Specifically, the number of parts of the novolak-type phenol resin to be blended is, for example, 40 parts by mass or more, preferably 50 parts by mass or more, and more preferably 75 parts by mass or less, based on 100 parts by mass of the epoxy resin. Is 60 parts by mass or less.

The thermoplastic resin containing a carboxyl group is, for example, a reactive resin capable of reacting with an epoxy resin and a novolak-type phenol resin. Specifically, the carboxyl group contained in the thermoplastic resin is the epoxy of the epoxy resin. It reacts with the group and the hydroxyl group of the novolak type phenol resin.
Examples of the thermoplastic resin containing a carboxyl group include an acrylic resin containing a carboxyl group.

As the acrylic resin, for example, one or more (meth) acrylic acid alkyl esters having a linear or branched alkyl group and a monomer containing a carboxyl group are used as monomer components, and these monomer components are polymerized. Examples thereof include an acrylic polymer containing a carboxyl group (carboxyl group-containing (meth) acrylic acid ester-based monomer) obtained by the above. In addition, "(meth) acrylic" represents "acrylic and / or methacrylic".

Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, amyl, isoamyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, and the like. Examples thereof include alkyl groups having 1 to 20 carbon atoms such as isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, octadecyl and dodecyl. Preferred are alkyl groups having 1 to 6 carbon atoms.

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

The acid value of the thermoplastic resin containing a carboxyl group is, for example, 1 mgKOH / g or more, preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably 30 mgKOH / g or more, and particularly preferably. It is in excess of 30 mgKOH / g, and is, for example, 100 mgKOH / g or less, preferably 50 mgKOH / g or less, and more preferably 40 mgKOH / g or less. The acid value is determined by the neutralization titration method specified in JIS K 0070-1992.

When the acid value of the thermoplastic resin containing a carboxyl group is equal to or higher than the above-mentioned lower limit, the reaction rate R at a low temperature described later can be increased. On the other hand, if the acid value of the thermoplastic resin containing a carboxyl group is equal to or lower than the above-mentioned upper limit, the reaction rate R required to reduce the protrusion length L1 is maintained while maintaining high fluidity of the resin at a low temperature ( Can be secured).

The weight average molecular weight of the thermoplastic resin containing a carboxyl group is, for example, 100,000 or more, preferably 300,000 or more, and for example, 1 million or less, preferably 900,000 or less, more preferably 800,000. Hereinafter, it is more preferably 700,000 or less. The weight average molecular weight is measured by gel permeation chromatography (GPC) based on a standard polystyrene conversion value.

The glass transition temperature Tg of the thermoplastic resin containing a carboxyl group is, for example, 20 ° C. or lower, preferably 10 ° C. or lower, more preferably 5 ° C. or lower, and for example, −70 ° C. or higher, preferably −70 ° C. or higher. −50 ° C. or higher, more preferably −25 ° C. or higher, still more preferably −20 ° C. or higher, particularly preferably −10 ° C. or higher, and most preferably −5 ° C. or higher. The glass transition temperature Tg of the thermoplastic resin containing a carboxyl group is, for example, a theoretical value obtained by the Fox equation, and a specific calculation method thereof is described in, for example, Japanese Patent Application Laid-Open No. 2016-175976. ..

When the glass transition temperature Tg is equal to or higher than the above lower limit, the semiconductor element encapsulating sheet 1 protrudes from the substrate 2 on which the semiconductor element 3 is mounted when the semiconductor element 3 is sealed with the semiconductor element encapsulating sheet 1. Can be effectively suppressed. When the glass transition temperature Tg is not more than the above-mentioned upper limit, the semiconductor element encapsulating sheet 1 can reliably enclose (embed) the semiconductor element 3.

The number of parts of the carboxyl group-containing thermoplastic resin to be blended with respect to 100 parts by mass of the total amount of the epoxy resin and the novolak type phenol resin is, for example, 10 parts by mass or more, preferably 25 parts by mass or more, and more preferably 40 parts by mass or more. For example, 90 parts by mass or less, preferably 75 parts by mass or less, more preferably 50 parts by mass or less, still more preferably less than 50 parts by mass.

The proportion of the thermoplastic resin containing a carboxyl group in the epoxy-based encapsulation composition (semiconductor element encapsulation sheet 1) is, for example, 0.1% by mass or more, preferably 0.5% by mass or more. It is preferably in excess of 1% by mass, and is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1.5% by mass or less.

When the proportion of the thermoplastic resin containing a carboxyl group and / or the number of compounding portions is equal to or higher than the above lower limit, the reaction rate R at a low temperature described later is increased, and when the semiconductor device encapsulation sheet 1 is hot-pressed, the surroundings are used. It is possible to prevent the member of the above from being contaminated by the semiconductor element encapsulating sheet 1.

On the other hand, if the proportion of the thermoplastic resin containing the carboxyl group and / or the number of compounding portions is not more than the above upper limit, the reaction is carried out without lack of the carboxyl group, and the unreacted carboxyl group does not remain (or is as small as possible). State) can be.

The epoxy-based encapsulation composition may also contain additives such as a curing accelerator, inorganic particles, pigments, and a silane coupling agent.

The curing accelerator is a catalyst (thermosetting catalyst) (epoxy resin curing accelerator) that accelerates the curing of the epoxy resin by heating, and is, for example, an organic phosphorus compound, for example, 2-phenyl-4,5-dihydroxy. Examples thereof include imidazole compounds such as methylimidazole (2PHZ-PW) and 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ). Preferred are imidazole compounds. The number of parts of the curing accelerator to be blended 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 epoxy resin.

The inorganic particles are fillers for improving the strength of the semiconductor device encapsulating sheet 1. Examples of the material of the inorganic particles include inorganic compounds such as quartz glass, talc, silica, alumina, aluminum nitride, silicon nitride, and boron nitride. These can be used alone or in combination of two or more. Preferred is silica.

The shape of the inorganic particles is not particularly limited, and examples thereof include a substantially spherical shape, a substantially plate shape, a substantially needle shape, and an indefinite shape. Preferred is a substantially spherical shape.

The average value (average particle diameter in the case of a substantially spherical shape) M of the maximum length of the inorganic particles is, for example, 50 μm or less, preferably 20 μm or less, more preferably 10 μm or less, and for example, 0. It is 1 μm or more, preferably 0.5 μm or more. The average particle size M is obtained as a D50 value (cumulative 50% median diameter) based on, for example, the particle size distribution obtained by the particle size distribution measurement method in the laser scattering method.

Further, the inorganic particles can include the first inorganic particles and the second inorganic particles having an average value M2 having a maximum length smaller than the average value M1 of the maximum lengths of the first inorganic particles.

The average value of the maximum lengths of the first inorganic particles (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 for example, 50 μm or less, preferably 30 μm. It is as follows.

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

The ratio (M1 / M2) of the average value of the maximum lengths of the first inorganic particles to the average value of the maximum lengths of the second inorganic particles is, for example, 2 or more, preferably 5 or more, and for example, for example. It is 50 or less, preferably 40 or less.

The materials of the first inorganic particles and the second inorganic particles may be the same or different from each other. Preferably, the materials of the first inorganic particles and the second inorganic particles are both the same, specifically silica.

Further, the surface of the inorganic particles may be partially or wholly surface-treated with a silane coupling agent or the like. Preferably, the first inorganic particles which have not been surface-treated and the second inorganic particles which have been surface-treated are used in combination.

When the inorganic particles include the above-mentioned first inorganic particles and the second inorganic particles, the first inorganic particles and the second inorganic particles are contained in the semiconductor device encapsulating sheet 1 with respect to the epoxy-based encapsulating composition. It can be efficiently dispersed to improve the toughness of the semiconductor device encapsulating sheet 1.

The content ratio of the inorganic particles (in the case of the combined use of the first inorganic particles and the second inorganic particles, the total amount thereof) exceeds, for example, 50% by mass in the semiconductor device encapsulation sheet 1 (epoxy encapsulation composition). It is preferably 70% by mass or more, more preferably 80% by mass or more, and for example, 90% by mass or less, preferably 87% by mass or less.

When the inorganic particles include the above-mentioned first inorganic particles and the second inorganic particles, the content ratio of the first inorganic particles is, for example, 40% by mass or more, preferably 50% by mass in the epoxy-based encapsulating composition. % Excess, and for example, 80% by mass or less, preferably 70% by mass or less.

When the inorganic particles include the above-mentioned first inorganic particles and the second inorganic particles, the number of parts of the second inorganic particles to be blended is, for example, 30 parts by mass or more, preferably 30 parts by mass or more, based on 100 parts by mass of the first inorganic particles. , 50 parts by mass or more, more preferably more than 50 parts by mass, and for example, less than 100 parts by mass, preferably 80 parts by mass or less, more preferably 70 parts by mass or less.

When the number of the second inorganic particles is not less than the above-mentioned lower limit, the relatively large gaps between the first inorganic particles are efficiently filled with the second inorganic particles, and the semiconductor device encapsulation sheet 1 is hot-pressed. It is possible to reduce the fluidity when the particles are used, and it is possible to prevent the surrounding members from being contaminated by the semiconductor element encapsulating sheet 1.

On the other hand, if the number of copies of the second inorganic particles is not more than the above-mentioned upper limit, it is possible to suppress an excessive increase in resin viscosity due to the influence of the inorganic particles.

Examples of the pigment include black pigments such as carbon black. The average particle size of the pigment is, for example, 0.001 μm or more, 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 with respect to the epoxy-based sealing composition.

The silane coupling agent is formulated to treat the surface of the inorganic particles (surface treatment). Examples of the silane coupling agent include a silane coupling agent containing an epoxy group. Examples of the silane coupling agent containing an epoxy group include 3-glycidoxydialkyldialkoxysilanes such as 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane, for example, 3-. Examples thereof include 3-glycidoxyalkyltrialkoxysilanes such as glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. Preferred are 3-glycidoxyalkyltrialkoxysilanes. The number of parts of the silane coupling agent to be blended is, for example, 0.1 part by mass or more, preferably 1 part by mass or more, and for example, 10 parts by mass or less, preferably 5 parts with respect to 100 parts by mass of the inorganic particles. It is less than the mass part.

The epoxy-based sealing composition is prepared by blending an epoxy resin, a novolak-type phenol resin, a thermoplastic resin containing a carboxyl group, and if necessary, an additive, and mixing them.

Next, a method for manufacturing the semiconductor element encapsulation sheet 1 will be described.

To produce the semiconductor device encapsulation sheet 1, for example, an epoxy-based encapsulation composition is dissolved and / or dispersed in a solvent (eg, methyl ethyl ketone, toluene, ethyl acetate, etc.) to prepare a varnish, which is then used. , Is applied to the first release sheet 15 and dried. As a result, the semiconductor element encapsulation sheet 1 is manufactured in a state of being supported by the first release sheet 15.

The first release sheet 15 has, for example, a sheet shape extending in the surface direction and has a peripheral surface. The peripheral surface is a peripheral side surface including the peripheral edge of the first release sheet 15. The material of the first release sheet 15 includes, for example, polypropylene, polyethylene, polyolefins such as copolymers thereof, for example, polymers such as polyimide, and for example, metals such as ceramics. Preferred are polymers, more preferably polyolefins. Further, the surface of the first release sheet 15 may be subjected to a mold release treatment. The thickness of the first release sheet 15 is, for example, 1 μm or more, preferably 10 μm or more, and for example, 1000 μm or less, preferably 500 μm or less.

Then, the second release sheet 25 as an example of the release sheet covers one side 16 of the semiconductor element encapsulation sheet 1 in the thickness direction. Specifically, the second release sheet 25 is arranged on the opposite side of the first release sheet 15 with respect to the semiconductor element encapsulation sheet 1. That is, the semiconductor element encapsulation sheet 1 is manufactured in a state of being sandwiched between the first release sheet 15 and the second release sheet 25 in the thickness direction.

The second release sheet 25 has the same shape, material, and thickness as the first release sheet 15. The second release sheet 25 has a second peripheral surface 9 which is a peripheral side surface including the peripheral edge of the second release sheet 25. The second peripheral surface 9 is flush with the first peripheral surface 6 of the semiconductor element encapsulation sheet 1.

On the other hand, it is also possible to produce the semiconductor device encapsulation sheet 1 from the epoxy-based encapsulation composition at once by kneading extrusion without preparing a varnish. The heating conditions in the kneading extrusion are conditions in which the epoxy-based sealing composition is not completely cured.

The epoxy-based encapsulation composition in the semiconductor device encapsulation sheet 1 is, for example, a B stage (semi-cured rather than completely cured). The B stage is a state in which the epoxy-based sealing composition is between the liquid A stage and the completely cured C stage, and the curing and gelling proceed slightly, and the compressive modulus is the C stage. It is in a state smaller than the elastic modulus.

As a result, the semiconductor element encapsulation sheet 1 is manufactured.

The thickness of the semiconductor device encapsulation sheet 1 is not particularly limited, and is, for example, 100 μm or more, and is, for example, 2000 μm or less.

The semiconductor element encapsulation sheet 1 has a protrusion length L1 measured by the following method of 3 mm or less. The protrusion length L1 is preferably 2.5 mm or less, more preferably 2 mm or less, still more preferably 1.5 mm or less, and most preferably 0 mm.

If the protrusion length L1 exceeds the above-mentioned upper limit, it is possible to prevent the surrounding members from being contaminated by the semiconductor element sealing sheet 1 when the semiconductor element 3 is sealed.

The semiconductor element encapsulation sheet 1 having a thickness of 260 μm, a length of 5 cm, and a width of 5 cm is supported by a second release sheet 25 having the same length and width as the semiconductor element encapsulation sheet 1, and is 6 cm in length. The alumina plate 7, the semiconductor element encapsulating sheet 1 and the second release sheet 25 are arranged so as to be arranged in order on one side in the thickness direction on the facing surface 8 which is an example of one side in the thickness direction of the alumina plate 7 having a width of 6 cm. , They are hot-pressed in the thickness direction at 70 ° C. for 60 seconds with a force of 360 N, and then the outward protrusion length L1 of the semiconductor element encapsulating sheet 1 is measured.

Specifically, the second release sheet 25 and the semiconductor element encapsulation sheet 1 described above are externally processed (for example, cut) so that they both have the same vertical and horizontal dimensions. As a result, the first peripheral surface 6 of the semiconductor element encapsulation sheet 1 and the second peripheral surface 9 of the second release sheet 25 are flush with each other.

Next, the second release sheet 25 is arranged on the lower plate 21 so that the second release sheet 25 faces upward and the semiconductor element encapsulation sheet 1 faces the lower plate 21 of the hot press 23, and then the upper plate 22 and the lower plate 21 are arranged. While sandwiching the alumina plate 7, the semiconductor element encapsulating sheet 1 and the second release sheet 25, they are pressed.

The vertical and horizontal dimensions of the upper plate 22 are larger than those of the second release sheet 25. The vertical and horizontal dimensions of the lower plate 21 are larger than those of the alumina plate 7.

Further, the temperature of 70 ° C. at the time of hot pressing is a temperature at which softening of the semiconductor element encapsulating sheet 1 is allowed, but the semiconductor element encapsulating sheet 1 is not completely cured.

Further, the semiconductor device encapsulation sheet 1 has a reaction rate R obtained by the following method, for example, 50% or more, preferably 60% or more, more preferably 70% or more, still more preferably 80%. The above is particularly preferably 80% or more, most preferably 82% or more, and for example, 95% or less.

The differential scanning calorimetry (DSC measurement) of the semiconductor element encapsulation sheet 1 (before heating, that is, the unheated semiconductor element encapsulation sheet 1 described below) is measured under the following conditions, and the first calorific value is generated. Get H1.

Measurement temperature range: 0 to 300 ° C
Temperature rise rate: 10 ° C / min Measured mass: 15 mg
Separately, the semiconductor element encapsulation sheet 1 is heated at 150 ° C. for 10 minutes, and the above-mentioned semiconductor element encapsulation sheet (that is, the heated semiconductor element encapsulation sheet 1) is differentially mounted under the above conditions. The scanning calorific value is measured (DSC measurement) to obtain the second calorific value H2.

Then, the percentage ([H1-H2] / H1 × 100%) of the calorific value [H1-H2] obtained by subtracting the second calorific value H2 from the first calorific value H1 with respect to the first calorific value H1 is determined as the reaction rate R.

This reaction rate R means the ratio of the amount of heat [H1-H2] generated when heating at a predetermined temperature (relatively low temperature). Therefore, when the reaction rate R is high, it means that most of the epoxy-based sealing compositions have reacted at a predetermined temperature (relatively low temperature), while when the reaction rate R is low, it means that the epoxy-based sealing composition has reacted. It means that the composition reacts only slightly at a given temperature (relatively low temperature).

When the reaction rate R is equal to or higher than the above-mentioned lower limit, the epoxy-based sealing composition reacts at a low temperature. Therefore, when the above-mentioned protrusion length L1 is shortened and the semiconductor element encapsulation sheet 1 is hot-pressed, it is possible to prevent the surrounding members from being contaminated by the semiconductor element encapsulation sheet 1.

Next, a method of sealing the semiconductor element 3 using the semiconductor element encapsulating sheet 1 to manufacture the semiconductor element package 5 will be described.

The method for manufacturing the semiconductor element package 5 includes a step of preparing the semiconductor element 3, a step of preparing a semiconductor element encapsulating sheet 1, and a semiconductor element encapsulating sheet 1 for encapsulating the semiconductor element 3 to seal the semiconductor element. A step of preparing a cured sheet 20 from the stopping sheet 1 and obtaining a semiconductor device package 5 is provided.

In this method, as shown in FIG. 3A, first, the semiconductor element 3 and the substrate 2 are prepared.

The semiconductor element 3 is a semiconductor chip and has a substantially flat plate shape extending in the plane direction. The semiconductor element 3 is not particularly limited. Terminals are provided on the other surface (lower surface) of the semiconductor element 3 in the thickness direction.

The semiconductor element 3 is mounted on one side (upper surface) of the substrate 2 in the thickness direction. Specifically, the semiconductor element 3 is, for example, flip-chip mounted on the substrate 2.

Further, a plurality of semiconductor elements 3 are arranged on the substrate 2 at intervals in the plane direction.

The substrate 2 has a substantially flat shape extending in the plane direction. The substrate 2 has a size surrounding a plurality of semiconductor elements 3 in a plan view. That is, the substrate 2 has an overlapping region 11 that overlaps with the plurality of semiconductor elements 3 when projected in the thickness direction, and an exposed region 12 that does not overlap with the plurality of semiconductor elements 3 and is exposed from the substrate 2. Further, the substrate 2 is arranged in the overlapping region 11 and is arranged in the substrate terminal (not shown) in contact with the terminal of the semiconductor element 3, and the substrate wiring is arranged in the exposed region 12 and is continuous with the substrate terminal (not shown). Has.

In this method, the semiconductor device encapsulation sheet 1 is then prepared. The first release sheet 15 is peeled from the semiconductor element encapsulation sheet 1.

After that, the semiconductor element encapsulating sheet 1 is arranged on the semiconductor element 3 so as to be in contact with one surface (upper surface) in the thickness direction of the semiconductor element 3.

As shown in FIG. 3B, the semiconductor element 3 is then sealed with the semiconductor element sealing sheet 1.

For example, a flat plate press (not shown) provided with a lower plate and an upper plate is used to heat and pressurize the semiconductor element sealing sheet 1, and the semiconductor element sealing sheet 1 seals a plurality of semiconductor elements 3. do. That is, the semiconductor element encapsulation sheet 1 is hot-pressed via the second release sheet 25.

Further, the semiconductor element encapsulation sheet 1 is thermoset by the above-mentioned heating. Specifically, once softened, the epoxy-based encapsulation composition of the semiconductor device encapsulation sheet 1 is completely cured.

The heating conditions are conditions under which the epoxy-based sealing composition is completely cured. Specifically, the heating temperature is, for example, 85 ° C. or higher, preferably 100 ° C. or higher, and for example, 125 ° C. or lower, preferably 110 ° C. or lower. The heating time is, for example, 10 minutes or more, preferably 30 minutes or more, and for example, 300 minutes or less, preferably 180 minutes or less. The pressure is not particularly limited, and is, for example, 0.1 MPa or more, preferably 0.5 MPa or more, and for example, 10 MPa or less, preferably 5 MPa or less.

The semiconductor element encapsulation sheet 1 once flows and softens, and the semiconductor element 3 is embedded. In other words, the semiconductor element 3 is embedded in the semiconductor element encapsulating sheet 1.

At the same time, the first peripheral surface 6 of the semiconductor element encapsulation sheet 1 projects outward in the surface direction. The overhang length L2 of the first peripheral surface 6 is allowed to be larger than the above-mentioned overhang length L1L. Specifically, for example, the following formula (1), preferably the following formula (2), is used. Preferably, the following formula (3) is satisfied.

1 ≦ (overhang length L2) / (overhang length L1) <2 (1)
1 ≦ (overhang length L2) / (overhang length L1) <1.5 (2)
1 ≦ (overhang length L2) / (overhang length L1) <1.25 (3)
The overhang length L2 is based on the position of the first peripheral surface 6 of the semiconductor element encapsulating sheet 1 before encapsulation shown in FIG. 3A, and the semiconductor element encapsulating sheet 1 in FIG. 3B is based on this reference. It is the distance to the peripheral edge that protrudes to the outside. The above-mentioned reference is usually in the same position as the second peripheral surface 9 of the second release sheet 25.

Subsequently, the semiconductor element encapsulation sheet 1 covers the peripheral side surface of the semiconductor element 3 and contacts the exposed region 12 on the facing surface.

As a result, the semiconductor element 3 is sealed by the semiconductor element sealing sheet 1. Further, the exposed region 12 on the substrate 2 is in contact (adhesion) with the semiconductor element encapsulating sheet 1.

After that, the second release sheet 25 is peeled from the semiconductor element encapsulation sheet 1.

The semiconductor element encapsulation sheet 1 that encloses the semiconductor element 3 and comes into contact with the exposed region 12 of the substrate 2 is already in a thermosetting (completely cured) (C stage) state by heating. Therefore, the semiconductor element encapsulation sheet 1 becomes the cured body sheet 20.

After that, the semiconductor element encapsulating sheet 1 (or the cured body sheet 20) is removed from the flat plate press and put into another heating furnace when it is desired to further promote the thermal curing.

This makes it possible to obtain a semiconductor device package 5 including a substrate 2, a plurality of semiconductor devices 3, and a cured body sheet 20.

Then, if necessary, the semiconductor element package 5 is separated into pieces corresponding to the semiconductor element 3 by, for example, cutting with a dicing saw.

Since the semiconductor element encapsulation sheet 1 has a protrusion length L1 measured by the above method of 3 mm or less, the surrounding members, specifically, the heat press, are used for the semiconductor element encapsulation sheet 1 ( The semiconductor device 3 can be reliably sealed and the semiconductor device package 5 can be efficiently manufactured while suppressing contamination by the first peripheral surface 6) of the above.

Further, since the protrusion length is equal to or less than the above upper limit, the board wiring (not shown) of the board 2 can be inspected (pattern inspection), and further, the presence or absence of foreign matter on one side (upper surface) in the thickness direction of the board 2 can be inspected. can.

<Modification example>
In each of the following modifications, the same members as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, each modification can exhibit the same effect as that of one embodiment, except for special mention. Further, one embodiment and each modification can be appropriately combined.

In FIG. 1, the semiconductor device encapsulation sheet 1 is formed from a single layer, but for example, although not shown, it may be a laminated body having a plurality of layers.

Further, the single semiconductor element 3 can be sealed by the semiconductor element sealing sheet 1.

Further, in one embodiment, the semiconductor element sealing sheet 1 is mentioned as an example of the sealing sheet to seal the semiconductor element 3, but the present invention is not limited to this, and for example, although not shown, other It may be an electronic element encapsulation sheet for encapsulating an electronic element. In this case, the electronic element encapsulation sheet can be used to enclose the electronic element to manufacture an electronic element package.

Examples and comparative examples are shown below, and the present invention will be described in more detail. The present invention is not limited to Examples and Comparative Examples. In addition, specific numerical values such as the compounding ratio (content ratio), physical property values, parameters, etc. used in the following description are the compounding ratios corresponding to them described in the above-mentioned "form for carrying out the invention" (forms for carrying out the invention). It can be replaced with the upper limit (value defined as "less than or equal to" or "less than") or the lower limit (value defined as "greater than or equal to" or "excess") such as content ratio), physical property value, parameter, etc. can.

Each component used in Examples and Comparative Examples is shown below.

Epoxy resin: YSLV-80XY manufactured by Nippon Steel Chemical Co., Ltd. (bisphenol F type epoxy resin, epoxy equivalent 200 g / eq. Softening point 80 ° C.)
Novolac type phenol resin: LVR-8210DL manufactured by Gunei Chemical Co., Ltd. (epoxy resin curing agent, hydroxyl group equivalent: 104 g / eq., Softening point: 60 ° C.)
Carboxyl group-containing thermoplastic resin: HME-2006M manufactured by Negami Kogyo Co., Ltd., carboxyl group-containing acrylic acid ester polymer, weight average molecular weight: about 850,000, solid content concentration 20% (methyl ethyl ketone solution), glass transition temperature Tg = -30 ° C, acid value: 30 mgKOH / g
Carboxyl group-containing thermoplastic resin: SG-70LN manufactured by Nagase ChemteX, carboxyl group-containing acrylic acid ester polymer, weight average molecular weight: about 900,000, solid content concentration 12.5% (methyl ethyl ketone solution), glass Transition temperature Tg = -13 ° C, acid value: 5 mgKOH / g
Carboxyl group-containing thermoplastic resin: SG-N50 manufactured by Nagase ChemteX, carboxyl group-containing acrylic acid ester polymer, weight average molecular weight: about 400,000, solid content concentration 25% (methyl ethyl ketone solution), glass transition temperature Tg = 0 ° C., acid value: 35 mgKOH / g
Carboxyl-free thermoplastic resin: AC-019 manufactured by Negami Kogyo Co., Ltd., carboxyl group-free acrylic acid ester polymer, weight average molecular weight: about 1.1 million, solid content concentration 20% (methyl ethyl ketone solution), glass transition temperature Tg = -15 ° C, acid value: 0 mgKOH / g
Epoxy resin curing accelerator: 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazole) manufactured by Shikoku Chemicals Corporation
First Inorganic Particles: FB-8SM manufactured by Denka Co., Ltd. (spherical molten silica powder (inorganic particles), average particle diameter 15 μm)
Second inorganic particles: Inorganic particles obtained by surface-treating SC220G-SMJ (average particle size 0.5 μm) manufactured by Admatex with 3-methacryloxypropyltrimethoxysilane (product name: KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). SC220G-SMJ Inorganic particles surface-treated with 1 part by mass of silane coupling agent with respect to 100 parts by mass.

Pigment: # 20 (carbon black) manufactured by Mitsubishi Chemical Corporation
Silane coupling agent: KBM-403 (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
Examples 1 to 4 and Comparative Example 1
Each component was dissolved and dispersed in methyl ethyl ketone according to the formulation shown in Table 1 to obtain a varnish. The solid content concentration of the varnish was 80% by mass.

After applying the varnish to the surface of the first release sheet 15, it was dried at 90 ° C. for 5 minutes. As a result, a B-stage semiconductor device encapsulation sheet 1 having a thickness of 260 μm was manufactured. Then, the upper surface of the semiconductor element encapsulation sheet 1 was covered with the second release sheet 25.

(evaluation)
The following items were evaluated for the semiconductor device encapsulation sheet 1. The results are shown in Table 1.

(Measurement of protrusion length L1)
As shown in FIG. 2A, a semiconductor device encapsulation sheet 1 supported by the first release sheet 15 and the second release sheet 25 and having a thickness of 260 μm is prepared and cut into a size of 5 cm in length and 5 cm in width. did. As a result, the first peripheral surface 6 of the semiconductor element encapsulation sheet 1 and the second peripheral surface 9 of the second release sheet 25 became flush with each other.

Subsequently, the first release sheet 15 is peeled from the semiconductor element encapsulation sheet 1, and the semiconductor element encapsulation sheet 1 is supported by the second release sheet 25, and the alumina plate 7 having a length of 6 cm and a width of 6 cm is supported. The alumina plate 7, the semiconductor element encapsulating sheet 1, and the second release sheet 25 were arranged so as to be arranged in order on the upper side.

As shown in FIG. 2B, they are then placed on the lower plate 21 of the hot press 23 (part number VS008-1515, vacuum hot press, manufactured by Mikado Technos), and then the inside of the hot press 23 is depressurized for 10 seconds. Subsequently, the alumina plate 7, the first peripheral surface 6 and the second release sheet 25 are hot-pressed by the upper plate 22 and the lower plate 21 with a force of 360 N at 70 ° C. for 60 seconds. After that, the protrusion length L1 from the second release sheet 25 of the semiconductor element encapsulation sheet 1 to the outside was measured. Specifically, the protrusion length L1 of the first peripheral surface 6 of the semiconductor element encapsulation sheet 1 from the second peripheral surface 9 of the second release sheet 25 to the outside was measured.

The protrusion length L1 was calculated as an average value of each value of the four first peripheral surfaces 6 of the semiconductor element encapsulation sheet 1.

(Measurement of reaction rate R)
The differential scanning calorimetry (DSC measurement) of the (unheated) semiconductor device encapsulation sheet 1 before heating was measured under the following conditions to obtain a first calorific value H1.

Measurement temperature range: 0 to 300 ° C
Temperature rise rate: 10 ° C / min Measured mass: 15 mg
DSC device: DSC-Q2000, manufactured by TA Instruments, Inc. Separately, the semiconductor element encapsulation sheet 1 is heated at 150 ° C. for 10 minutes, and the semiconductor element encapsulation sheet 1 (semiconductor element encapsulation after heating) is heated. The differential scanning calorimetry was measured (DSC measurement) on the sheet 1) under the above conditions to obtain a second calorific value H2.

Then, the percentage ([H1-H2] / H1 × 100%) of the calorific value [H1-H2] obtained by subtracting the second calorific value H2 from the first calorific value H1 with respect to the first calorific value H1 is determined as the reaction rate R.

Unless otherwise specified in Table 1, the numerical value is the number of compounded parts (number of parts contained).

1 Semiconductor element encapsulation sheet (an example of encapsulation sheet)
25 Second release sheet L1 Overhang length R Reaction rate

Claims (6)

It contains an epoxy resin, a novolak-type phenol resin, and a thermoplastic resin containing a carboxyl group.
A sealing sheet having a protrusion length L1 measured by the following method of 3 mm or less.
The sealing sheet having a thickness of 260 μm, a length of 5 cm, and a width of 5 cm is supported by a release sheet having the same length and width as the sealing sheet, and the alumina plate having a length of 6 cm and a width of 6 cm is supported. The alumina plate, the sealing sheet, and the release sheet are arranged on one side in the thickness direction so as to be arranged in order on one side in the thickness direction, and they are placed at 70 ° C. for 60 seconds with a force of 360 N in the thickness direction. Then, the protrusion length L1 of the sealing sheet from the release sheet to the outside in the direction orthogonal to the thickness direction is measured. The sealing sheet according to claim 1, wherein the acid value of the thermoplastic resin is 10 mgKOH / g or more and 40 mgKOH / g or less. The sealing sheet according to claim 1 or 2, wherein the glass transition temperature of the thermoplastic resin is −20 ° C. or higher and 10 ° C. or lower. Any one of claims 1 to 3, wherein the blending number of the thermoplastic resin with respect to the total amount of 100 parts by mass of the epoxy resin and the novolak type phenol resin is 10 parts by mass or more and 90 parts by mass or less. The sealing sheet described in the section. Furthermore, with the first inorganic particles,
It contains a second inorganic particle having an average particle diameter smaller than the average particle diameter of the first inorganic particle.
The seal according to any one of claims 1 to 4, wherein the blending number of the second inorganic particles with respect to 100 parts by mass of the first inorganic particles is 50 parts by mass or more and less than 100 parts by mass. Stop sheet. The sealing sheet according to any one of claims 1 to 5, wherein the reaction rate R obtained by the following method is 50% or more.
The differential scanning calorimetry of the sealing sheet 1 is measured under the following conditions to obtain a first calorific value H1.
Measurement temperature range: 0 to 300 ° C
Temperature rise rate: 10 ° C / min Measured mass: 15 mg
Separately, the sealing sheet is heated at 150 ° C. for 10 minutes, and the sealing sheet is measured for differential scanning calorimetry under the above conditions to obtain a second calorific value H2.
Then, the reaction rate is the percentage ([H1-H2] / H1 × 100%) of the calorific value [H1-H2] obtained by subtracting the second calorific value H2 from the first calorific value H1 with respect to the first calorific value H1. Obtained as R.

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