Sealing sheet

Abstract

The present invention provides a sealing sheet having excellent softness when heated, and excellent sealing and toughness of a semiconductor chip. The sealing sheet contains a thermosetting component and an inorganic filler. The proportion of the inorganic filler in the sealing sheet is 50% or more and 95% or less. The ratio of the Shore D hardness of the cured body sheet at 80°C as a cured product of the sealing sheet to the Shore D hardness of the cured body sheet at 25°C is 0.5 or more and less than 1.0.

Description

Technical Field

[0001] The present invention relates to a sealing sheet. Background Art

[0002] Conventionally, it is known that a plurality of semiconductor chips are embedded in a sealing resin sheet for sealing.

[0003] For example, a sealing resin sheet containing an epoxy resin, a phenol resin, an elastomer, an inorganic filler, and a curing accelerator has been proposed (see, for example, Japanese Patent Application Laid-Open No. 2014-15490). Summary of the invention

[0004] However, the sealing resin sheet embeds a plurality of semiconductor chips and solidifies them by heating to form a solidified body sheet. Then, the solidified body sheet is set on an adsorption platform with suction holes, and the solidified body sheet is fixed (closely attached) to the adsorption platform by driving a suction device connected to the suction holes. Next, the solidified body sheet is cut to separate the plurality of semiconductor chips. At this time, for the solidified body sheet, flexibility during heating is required, and it does not break even if it is heated by contact with a cutting machine while being attracted by the suction holes.

[0005] On the other hand, if the cured body sheet is too soft, there is a problem that the sealing property with respect to the semiconductor chip is reduced, and further the reliability of the semiconductor device including the semiconductor chip and the cured body sheet is reduced.

[0006] Furthermore, the cured sheet is also required to have excellent toughness.

[0007] The present invention provides a sealing sheet having excellent flexibility during heating, and excellent sealing properties and toughness for semiconductor chips.

[0008] The present invention (1) comprises a sealing sheet, which is a sealing sheet containing a thermosetting component and an inorganic filler, wherein the proportion of the inorganic filler in the sealing sheet is greater than 50% and less than 95%, and the ratio of the Shore D hardness of the cured body sheet at 80°C to the Shore D hardness of the cured body sheet at 25°C is greater than 0.5 and less than 1.0.

[0009] The present invention (2) comprises the sealing sheet according to (1), wherein the proportion of the inorganic filler in the sealing sheet is less than 70%.

[0010] The present invention (3) comprises the sealing sheet according to (1) or (2), wherein the Shore D hardness of the cured sheet at 25°C is 50 or more and 80 or less.

[0011] The present invention (4) comprises the sealing sheet according to any one of (1) to (3), wherein the glass transition temperature Tg of the cured sheet is 100° C. or lower.

[0012] The present invention (5) comprises the sealing sheet according to any one of (1) to (4), wherein the ratio of the tensile storage modulus E' of the cured sheet at 25°C to the tensile storage modulus E' of the cured sheet at 260°C is 10 or more and 500 or less.

[0013] In the sealing sheet of the present invention, the ratio of the inorganic filler in the sealing sheet is as high as 50% or more and 95% or less, and therefore the sheet is excellent in toughness.

[0014] Furthermore, since the ratio of the Shore D hardness of the cured sheet at 80° C. to the Shore D hardness of the cured sheet at 25° C. as a cured product of the sealing sheet is less than 1.0, the cured sheet has excellent flexibility when heated.

[0015] On the other hand, since the above ratio is 0.5 or more, the sealing property of the cured sheet is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A cross-sectional view showing a sheet for sealing a semiconductor element according to an embodiment of the sheet for sealing of the present invention.

[0017] Figure 2A to Figure 2B Show use Figure 1 The process diagram of a method of manufacturing a semiconductor element package assembly by sealing a semiconductor element with a semiconductor element sealing sheet shown in FIG. Figure 2A The process of placing the semiconductor element sealing sheet opposite to the plurality of semiconductor elements is shown. Figure 2B The step of sealing a plurality of semiconductor elements with a semiconductor element sealing sheet to obtain a semiconductor element package assembly is shown.

[0018] Figure 3 Show that Figure 2B The semiconductor device package assembly shown is singulated to obtain semiconductor device packages.

[0019] Figure 4 Show Figure 3 A variation of the process shown. DETAILED DESCRIPTION

[0020] Reference Figure 1 to Figure 3 Hereinafter, a semiconductor element sealing sheet which is one embodiment of the sealing sheet of the present invention will be described.

[0021] The semiconductor element sealing sheet 1 is a sealing sheet for sealing a semiconductor element 3 mounted on a substrate 2 .

[0022] The semiconductor element sealing sheet 1 is used to manufacture a semiconductor element package assembly 35 (see Figure 2B ) and semiconductor device package 5 (refer to Figure 3 ) components, rather than the semiconductor element package assembly 35 and the semiconductor element package 5 itself. The semiconductor element sealing sheet 1 does not include the semiconductor element 3 and the substrate 2 on which the semiconductor element 3 is mounted. Specifically, the semiconductor element sealing sheet 1 is a device that can be circulated in the form of an independent component and thus used in industry.

[0023] It should be noted that the semiconductor element sealing sheet 1 is not the cured body sheet 20 after the semiconductor element 3 is sealed, that is, the semiconductor element sealing sheet 1 is a sheet before the semiconductor element 3 is sealed.

[0024] like Figure 1 As shown, the semiconductor element sealing sheet 1 has a generally plate shape (film shape) extending in a direction (surface direction) perpendicular to the thickness direction. In addition, the semiconductor element sealing sheet 1 has a first surface 6 located on one side in the thickness direction and a second surface 7 opposite to the first surface 6 in the thickness direction.

[0025] The first surface 6 and the second surface 7 are both flat and parallel to each other.

[0026] The second surface 7 is a surface (lower surface) located on the other side in the thickness direction of the semiconductor element sealing sheet 1. Figure 2B As shown, the second surface 7 is a contact surface (the other surface in the thickness direction) that comes into contact with the semiconductor element 3 and the substrate 2 when the semiconductor element sealing sheet 1 seals the semiconductor element 3 .

[0027] The first surface 6 is an opposing surface (one surface in the thickness direction) (upper surface) that is arranged to be opposed to an opposing surface 8 (described later) of the substrate 2 with a gap in the thickness direction when the semiconductor element sealing sheet 1 seals the semiconductor element 3. Figure 3 As shown, the first surface 6 is a surface that contacts the suction surface (adsorption) 31 of the adsorption stage 30 when the semiconductor element package 5 is arranged on the adsorption stage 30 .

[0028] The material of the sheet 1 for sealing a semiconductor element is a sealing composition containing a thermosetting component and an inorganic filler.

[0029] The thermosetting component is a binder component that bonds the inorganic fillers together in the semiconductor element sealing sheet 1 (sealing composition), and is cured by heat to increase the hardness of the sealing composition.

[0030] The thermosetting component includes, for example, a sealing resin (main component), a curing agent, and a curing accelerator.

[0031] Examples of the sealing resin include epoxy resins, phenol resins, melamine resins, vinyl ester resins, cyanoester resins, maleimide resins, and siloxane resins. Preferably, the sealing resin is an epoxy resin from the viewpoint of heat resistance and the like.

[0032] Examples of the epoxy resin include bifunctional epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, modified bisphenol A epoxy resin, modified bisphenol F epoxy resin, and biphenyl epoxy resin, and polyfunctional epoxy resins having three or more functions such as phenol novolac epoxy resin, cresol novolac epoxy resin, trihydroxyphenylmethane epoxy resin, tetrahydroxyphenylethane epoxy resin, and dicyclopentadiene epoxy resin. These epoxy resins can be used alone or in combination of two or more.

[0033] Preferably, a bifunctional epoxy resin is used alone, and specifically, a bisphenol F epoxy resin is used alone.

[0034] The epoxy equivalent of the epoxy resin is, for example, 10 g / eq. or more, preferably 100 g / eq. or more, and, for example, 300 g / eq. or less, preferably 250 g / eq. or less.

[0035] 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.

[0036] In the sealing composition, the proportion of the epoxy resin 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. In addition, in the thermosetting component, the proportion of the epoxy resin is, for example, 50% by mass or more, preferably 60% by mass or more, and, for example, 90% by mass or less, preferably 80% by mass or less.

[0037] The curing agent is a component (preferably an epoxy resin curing agent) that cures the above-mentioned sealing resin (main component) by heating. Examples of the curing agent include phenolic resins such as phenol novolac resins.

[0038] For the proportion of the curing agent, if the sealing resin is an epoxy resin and the curing agent is a phenolic resin, the total of the hydroxyl groups in the phenolic resin is adjusted to, for example, 0.7 equivalents or more, preferably 0.9 equivalents or more, for example, 1.5 equivalents or less, preferably 1.2 equivalents or less relative to 100 parts by mass of the sealing resin. 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 or less.

[0039] The curing accelerator is a catalyst (thermosetting catalyst) (preferably an epoxy resin curing accelerator) that promotes the curing of the sealing resin by heating, and examples thereof include organic phosphorus compounds, imidazole compounds such as 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ), etc. Preferably, an imidazole compound can be mentioned. The amount of the curing accelerator is, for example, 0.05 parts by mass or more relative to 100 parts by mass of the sealing resin, and, for example, 5 parts by mass or less.

[0040] The inorganic filler is an inorganic particle that improves the strength of the semiconductor element sealing sheet 1. As the material of the inorganic filler, for example, inorganic compounds such as quartz glass, talc, silica, alumina, aluminum nitride, silicon nitride, and boron nitride can be cited. They can be used alone or in combination of two or more. Preferably, silica can be cited.

[0041] 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. Preferably, a substantially spherical shape is used.

[0042] The average value (if it is a substantially spherical shape, it is the average particle size) M of the maximum length of the inorganic filler is, for example, 50 μm or less, preferably 20 μm or less, more preferably 10 μm or less, and, for example, 0.1 μm or more, preferably 0.5 μm or more. It should be noted that the average particle size M is, for example, obtained as a D50 value (cumulative 50% median particle size) based on a particle size distribution obtained by a particle size distribution measurement method in a laser scattering method.

[0043] Alternatively, the inorganic filler may include a first filler and a second filler having an average value M2 of the maximum length smaller than the average value M1 of the maximum length of the first filler.

[0044] The average value of the maximum length of the first filler (the average particle size if the filler has 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 or less.

[0045] The average value of the maximum length of the second filler (the average particle size if the filler has a substantially spherical shape) M2 is, for example, less than 1 μm, or preferably 0.8 μm or less, and, for example, 0.01 μm or more, or preferably 0.1 μm or more.

[0046] The ratio (M1 / M2) of the average value of the maximum length of the first filler to the average value of the maximum length of the second filler is, for example, 2 or more, preferably 5 or more, and for example, 50 or less, preferably 20 or less.

[0047] The materials of the first filler and the second filler can be the same or different. Preferably, the materials of the first filler and the second filler are the same, specifically silicon dioxide.

[0048] Furthermore, the surface of the inorganic filler may be partially or entirely surface treated with a silane coupling agent, etc. Preferably, a first filler that has not been surface treated and a second filler that has been surface treated are used simultaneously.

[0049] In the semiconductor element sealing sheet 1 (sealing composition), the proportion of the inorganic filler (if the first filler and the second filler are used simultaneously, the total amount thereof) is 50% by mass or more, preferably more than 50% by mass, more preferably 55% by mass or more, further preferably 60% by mass or more, and is 95% by mass or less, for example, 90% by mass or less, preferably 85% by mass or less, more preferably 75% by mass or less, further preferably 70% by mass or less, and particularly preferably less than 70% by mass.

[0050] When the ratio of the inorganic filler is less than the above-mentioned lower limit, the toughness of the sheet 1 for semiconductor element sealing cannot be ensured.

[0051] On the other hand, when the ratio of the inorganic filler exceeds the above upper limit, the sheet 1 for sealing a semiconductor element becomes brittle and cannot reliably seal the semiconductor element 3 .

[0052] When the inorganic filler includes the first and second inorganic fillers, the proportion of the first inorganic filler in the sealing composition is, for example, 40 mass % or more, preferably more than 50 mass %, and, for example, 80 mass % or less, preferably 70 mass % or less.

[0053] When the inorganic filler includes the above-mentioned first inorganic filler and second inorganic filler, the amount of the second inorganic filler mixed relative to 100 parts by mass of the first inorganic filler is, for example, 30 parts by mass or more, preferably 50 parts by mass or more, more preferably more than 50 parts by mass, and is, for example, less than 100 parts by mass, preferably 80 parts by mass or less, more preferably 70 parts by mass or less.

[0054] In addition, additives such as thermoplastic resin, pigment, and silane coupling agent may be added to the sealing composition at an appropriate ratio.

[0055] Thermoplastic resin is a component that improves the flexibility of the cured sheet 20 when heated.

[0056] Examples of the thermoplastic resin include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylate copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin (6-nylon or 6,6-nylon, etc.), phenoxy resin, acrylic resin, saturated polyester resin (PET, etc.), polyamide-imide resin, fluororesin, styrene-isobutylene-styrene block copolymer, etc. These thermoplastic resins may be used alone or in combination of two or more thereof.

[0057] As the thermoplastic resin, from the viewpoint of improving dispersibility with the sealing resin (preferably epoxy resin), preferably, an acrylic resin is used.

[0058] Examples of acrylic resins include acrylic polymers obtained by polymerizing one or more (meth)acrylic acid alkyl esters having a linear or branched alkyl group as monomer components. It should be noted that "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid".

[0059] Examples of the alkyl group include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, octadecyl, and dodecyl. Preferably, an alkyl group having 1 to 6 carbon atoms is used.

[0060] The acrylic polymer may be a copolymer of an alkyl (meth)acrylate and other monomers (copolymerizable monomers).

[0061] Examples of other monomers (copolymerizable monomers) include glycidyl group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid, anhydride monomers such as maleic anhydride and itaconic anhydride, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 1,1-dihydroxybutyl (meth)acrylate. Hydroxyl-containing monomers such as 8-hydroxyoctyl acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate or (4-hydroxymethylcyclohexyl)methyl acrylate, sulfonic acid-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid, phosphate-containing monomers such as 2-hydroxyethylacryloyl phosphate, such as styrene monomers, such as acrylonitrile. These monomers can be used alone or in combination of two or more. Among them, carboxyl-containing monomers are preferably used.

[0062] The weight average molecular weight of the thermoplastic resin is, for example, 100,000 or more, preferably 300,000 or more, and, for example, 1,000,000 or less, preferably 800,000 or less. The weight average molecular weight is measured by gel permeation chromatography (GPC) based on standard polystyrene conversion values.

[0063] The ratio (solid content ratio) of the thermoplastic resin is adjusted so as not to hinder the thermal curing of the sealing composition, and specifically, it is, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 3.5% by mass or more, and, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 4% by mass or less, relative to the sealing composition.

[0064] It should be noted that the thermoplastic resin can also be prepared by diluting it with an appropriate solvent.

[0065] 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 relative to the sealing composition is, for example, 0.1 mass % or more, and for example, 2 mass % or less.

[0066] In order to treat the surface of the inorganic filler (surface treatment), a silane coupling agent is used. As a silane coupling agent, for example, a silane coupling agent containing an epoxy group is cited. As a silane coupling agent containing an epoxy group, for example, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxydialkyldialkoxysilane, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxyalkyltrialkoxysilane can be cited. Preferably, 3-glycidoxyalkyltrialkoxysilane can be cited. Relative to 100 parts by mass of inorganic filler, the mixing ratio of the silane coupling agent is, for example, more than 0.1 parts by mass, preferably more than 1 part by mass, and, for example, less than 10 parts by mass, preferably less than 5 parts by mass.

[0067] When preparing the sealing composition, a thermosetting component, an inorganic filler, and, if necessary, an additive are blended and mixed.

[0068] Next, a method for producing the sheet 1 for sealing a semiconductor element will be described.

[0069] When manufacturing the semiconductor element sealing sheet 1, for example, the sealing composition is dissolved and / or dispersed in a solvent (such as methyl ethyl ketone, toluene, ethyl acetate, etc.) to prepare a varnish, and the varnish is applied to the semiconductor element sealing sheet 1. Figure 1 The semiconductor element sealing sheet 1 is coated on the first release sheet 15 as shown and dried. Thus, the semiconductor element sealing sheet 1 is manufactured in a state where the semiconductor element sealing sheet 1 is supported on the first release sheet 15. Thereafter, the second release sheet 16 is arranged on the side opposite to the first release sheet 15 with respect to the semiconductor element sealing sheet 1. That is, the semiconductor element sealing sheet 1 is manufactured in a state where the semiconductor element sealing sheet 1 is sandwiched in the thickness direction by the first release sheet 15 and the second release sheet 16. The first surface 6 and the second surface 7 of the semiconductor element sealing sheet 1 are in contact with the second release sheet 16 and the first release sheet 15, respectively.

[0070] Each of the first peeling sheet 15 and the second peeling sheet 16 is flexible and has a sheet shape extending in the surface direction. Examples of the material of the first peeling sheet 15 and the second peeling sheet 16 include resins such as polyethylene terephthalate and polyimide, and metals such as stainless steel, and resins are preferred. In addition, the surfaces of the first peeling sheet 15 and the second peeling sheet 16 (the contact surface with the semiconductor element sealing sheet 1) may be subjected to a peeling treatment. The thickness of each of the first peeling sheet 15 and the second peeling sheet 16 is, for example, 1 μm or more, preferably 10 μm or more, and, for example, 1000 μm or less, preferably 500 μm or less.

[0071] On the other hand, the semiconductor element sealing sheet 1 can be produced from the sealing composition by kneading and extrusion without preparing the varnish. The first release sheet 15 and the second release sheet 16 are arranged on the semiconductor element sealing sheet 1 after extrusion.

[0072] The thermosetting component in the semiconductor element sealing sheet 1 is, for example, in stage B (semi-cured, not completely cured). Stage B is a state between stage A where the thermosetting component is liquid and stage C where it is completely cured, and is a state where curing and gelation are slightly advanced and the compressive elastic modulus is smaller than the elastic modulus of stage C.

[0073] Thus, the semiconductor element sealing sheet 1 is manufactured in a state where the first surface 6 and the second surface 7 are supported (protected) by the second release sheet 16 and the first release sheet 15 , respectively.

[0074] The thickness of the sheet 1 for semiconductor element sealing is not particularly limited, and is, for example, 100 μm or more, and, for example, 2000 μm or less.

[0075] Next, a method of manufacturing a semiconductor element package 5 by sealing a plurality of semiconductor elements 3 using the semiconductor element sealing sheet 1 and then cutting the cured body sheet 20 and the substrate 2 into individual pieces of the plurality of semiconductor elements 3 will be described.

[0076] The method for manufacturing the semiconductor element package 5 includes the following steps: a step of preparing a plurality of semiconductor elements 3 (see Figure 2A ); preparing a semiconductor element sealing sheet 1 step (refer to Figure 1 ); using a semiconductor element sealing sheet 1 to seal a plurality of semiconductor elements 3, from the semiconductor element sealing sheet 1 modulates a cured body sheet 20, and obtains a semiconductor element package assembly 35 of the process (reference Figure 2B and the semiconductor element package assembly 35 is cut to obtain a semiconductor element package 5 (reference Figure 3 ).

[0077] In this method, if Figure 2A As shown, first, the semiconductor element 3 is prepared.

[0078] The semiconductor element 3 is, for example, a semiconductor chip, and has a substantially flat plate shape extending in the plane direction. The semiconductor element 3 is not particularly limited. A terminal (not shown) is provided on the other surface (lower surface) in the thickness direction of the semiconductor element 3.

[0079] The semiconductor element 3 is mounted on the facing surface 8 (upper surface) (described later) of the substrate 2. Specifically, the semiconductor element 3 is mounted on the substrate 2 by, for example, a flip-chip method.

[0080] In addition, a plurality of semiconductor elements 3 are arranged on the substrate 2 at intervals from each other in the surface direction.

[0081] The substrate 2 has a substantially flat shape extending in the plane direction. The substrate 2 has an opposing surface 8 (upper surface) facing the plurality of semiconductor elements 3 and a second opposing surface 9 disposed at a distance from the opposing surface 8 in the thickness direction.

[0082] The facing surface 8 has a plane along the surface direction. In addition, the facing surface 8 has a size that completely surrounds the plurality of semiconductor elements 3 when viewed from above. That is, the facing surface 8 of the substrate 2 has an overlapping region 11 that overlaps with the plurality of semiconductor elements 3 and an exposed region 12 that does not overlap with the plurality of semiconductor elements 3 and is exposed from the substrate 2 when viewed from above. The facing surface 8 has substrate terminals (not shown) corresponding to the terminals (not shown) of the semiconductor elements 3 in the overlapping region 11.

[0083] The second facing surface 9 is parallel to the facing surface 8 and has a flat surface along the surface direction.

[0084] In this method, if Figure 1 As shown in FIG. 1 , a semiconductor element sealing sheet 1 is separately prepared. Specifically, Figure 1 As shown by the arrow, the first release sheet 15 is released from the second surface 7 of the semiconductor element sealing sheet 1 .

[0085] like Figure 2A As shown by the arrows, the semiconductor element sealing sheet 1 is then placed on the plurality of semiconductor elements 3 so that the second surface 7 thereof is in contact with one surface (upper surface) in the thickness direction of the semiconductor element 3 .

[0086] like Figure 2B As shown, next, the plurality of semiconductor elements 3 are sealed using the semiconductor element sealing sheet 1 .

[0087] For example, a flat plate press (not shown) having a lower plate and an upper plate is used to heat and pressurize the semiconductor element sealing sheet 1 , and the plurality of semiconductor elements 3 are sealed with the semiconductor element sealing sheet 1 .

[0088] Moreover, by the above-mentioned heating, the sheet 1 for sealing a semiconductor element is thermally cured. Specifically, after being softened once, the sealing composition of the sheet 1 for sealing a semiconductor element is completely cured (C-staged).

[0089] The heating conditions are conditions for completely curing the sealing composition. Specifically, the heating temperature is, for example, 85°C or more, preferably 100°C or more, and, for example, 125°C or less, preferably 110°C or less. 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.

[0090] The sheet 1 for sealing a semiconductor element is temporarily softened to embed the plurality of semiconductor elements 3. In other words, the plurality of semiconductor elements 3 are embedded in the sheet 1 for sealing a semiconductor element.

[0091] Next, the semiconductor element sealing sheet 1 covers the peripheral side surface of the semiconductor element 3 and comes into contact with the exposed region 12 in the facing surface 8 .

[0092] Thereby, the plurality of semiconductor elements 3 are sealed by the semiconductor element sealing sheet 1. In addition, the exposed region 12 in the substrate 2 is in contact with (closely attached to) the semiconductor element sealing sheet 1.

[0093] It should be noted that the semiconductor element sealing sheet 1 that seals the plurality of semiconductor elements 3 and contacts the exposed area 12 of the substrate 2 has been heated to a thermally cured (completely cured) (C stage) state. Therefore, the semiconductor element sealing sheet 1 becomes a cured body sheet 20. The cured body sheet 20 is a cured product of the semiconductor element sealing sheet 1.

[0094] like Figure 2B As shown by the arrows and imaginary lines, the second release sheet 16 is then peeled off from the first surface 6 of the cured sheet 20 .

[0095] Thereafter, when it is desired to further thermally cure the semiconductor element sealing sheet 1 (or the cured body sheet 20 ), it is removed from the flat plate press and placed in another heating furnace.

[0096] The Shore D hardness of the cured body sheet 20 at 25° C. is, for example, 50 or more, preferably 55 or more, and, for example, 80 or less, preferably 70 or less, and more preferably 65 or less.

[0097] If the Shore D hardness of the cured body sheet 20 at 25°C is not less than the above lower limit, the sealability of the cured body sheet 20 with respect to the semiconductor element 3 can be suppressed from decreasing, and further, the reliability of the semiconductor element package assembly 35 and the semiconductor element package 5 can be suppressed from decreasing. If the Shore D hardness of the cured body sheet 20 at 25°C is not more than the above upper limit, damage to the cured body sheet 20 can be suppressed.

[0098] The Shore D hardness of the cured body sheet 20 at 80° C. is, for example, 25 or more, preferably 30 or more, and, for example, 75 or less, preferably 70 or less, and more preferably 55 or less. If the Shore D hardness of the cured body sheet 20 at 80° C. is greater than or equal to the lower limit and less than or equal to the upper limit, a decrease in the reliability of the semiconductor element package assembly 35 and the semiconductor element package 5 can be suppressed, and damage to the cured body sheet 20 can be suppressed.

[0099] It should be noted that the Shore D hardness of the cured sheet 20 at 80°C refers to the Shore D hardness at an assumed temperature (around 80°C) when the cured sheet 20 is heated by contact with the dicing machine 25 in the step of cutting the semiconductor element package assembly 35 described below.

[0100] The ratio of the Shore D hardness of the cured body sheet 20 at 80°C to the Shore D hardness of the cured body sheet 20 at 25°C (Shore D hardness of the cured body sheet 20 at 80°C / Shore D hardness of the cured body sheet 20 at 25°C) is greater than 0.5, preferably greater than 0.55, and less than 1.0, preferably less than 0.99, more preferably less than 0.97, further preferably less than 0.95, further preferably less than 0.9, preferably less than 0.8, and more preferably less than 0.7.

[0101] The Shore D hardness is a D-type durometer hardness measured in accordance with JIS K 6253-3 (Rubber, vulcanized and thermoplastic rubber - Method for determining hardness - Part 3: Durometer hardness, 2012).

[0102] If the above ratio exceeds the above upper limit, in the process of cutting the semiconductor element package assembly 35, when the solidified body sheet 20 is heated by contact with the cutting machine 25, it becomes too hard, and therefore, damage (breakage or cracking) occurs in the solidified body sheet 20 due to the low pressure (negative pressure or vacuum pressure) in the suction hole 32 in the adsorption table 30.

[0103] On the other hand, if the ratio is lower than the lower limit, the sealing property of the cured sheet 20 with respect to the semiconductor element 3 is reduced, and the reliability of the semiconductor element package assembly 35 and the semiconductor element package 5 is reduced.

[0104] The glass transition temperature Tg of the cured sheet 20 is, for example, 150°C or less, more preferably 110°C or less, further preferably 100°C or less, particularly preferably 90°C or less, most preferably 85°C or less, and, for example, 70°C or more, preferably 75°C or more.

[0105] Regarding the glass transition temperature Tg of the solidified body sheet 20, the tensile storage elastic modulus E' and the tensile loss elastic modulus E", are obtained by dynamic viscoelasticity measurement in a stretching mode, a scanning temperature of 0 to 260°C, a frequency of 1 Hz, and a heating rate of 10°C / min. Based on these, a curve of tanδ (=E" / E') is calculated, and the glass transition temperature Tg is calculated as the peak value of tanδ.

[0106] If the glass transition temperature Tg of the solidified body sheet 20 is below the above-mentioned upper limit, even if the solidified body sheet 20 is heated by contact with a cutting device such as a cutting machine 25 during the process of cutting the semiconductor element package assembly 35, damage (breakage or cracking) of the solidified body sheet 20 can be suppressed.

[0107] On the other hand, if the glass transition temperature Tg of the cured sheet 20 is equal to or higher than the above lower limit, the sealability of the cured sheet 20 with respect to the semiconductor element 3 can be suppressed from decreasing, and further, the reliability of the semiconductor element package assembly 35 and the semiconductor element package 5 can be suppressed from decreasing.

[0108] The tensile storage modulus E′ of the cured sheet 20 at 25° C. is, for example, 0.1 GPa or more, preferably 0.5 GPa or more, and, for example, 20 GPa or less, preferably 10 GPa or less, particularly preferably 5 GPa or less, and most preferably 2.5 GPa or less.

[0109] The tensile storage modulus E' of the cured sheet 20 at 260°C is, for example, 0.001 GPa or more, preferably 0.003 GPa or more, and, for example, 5 GPa or less, preferably 3 GPa or less, more preferably 1 GPa or less, further preferably 0.1 GPa or less, and particularly preferably 0.01 GPa or less.

[0110] The tensile storage elastic modulus E' of the cured sheet 20 at 25°C and 260°C was determined by performing dynamic viscoelasticity measurement in a tensile mode, a scanning temperature of 0 to 260°C, a frequency of 1 Hz, and a heating rate of 10°C / min.

[0111] The ratio of the tensile storage modulus E' of the solidified body sheet 20 at 25°C to the tensile storage modulus E' of the solidified body sheet 20 at 260°C (tensile storage modulus E' of the solidified body sheet 20 at 25°C / tensile storage modulus E' of the solidified body sheet 20 at 260°C) is, for example, greater than 5, preferably greater than 10, more preferably greater than 50, further preferably greater than 150, particularly preferably greater than 200, most preferably greater than 250, and, for example, less than 500, preferably less than 400.

[0112] If the ratio of the tensile storage elastic modulus E' of the solidified body sheet 20 is greater than the above lower limit, it is possible to suppress damage to the solidified body sheet 20. If the ratio of the tensile storage elastic modulus E' of the solidified body sheet 20 is less than the above upper limit, it is possible to suppress a decrease in the sealing performance of the solidified body sheet 20 relative to the semiconductor element 3, and further, it is possible to suppress a decrease in the reliability of the semiconductor element package 5.

[0113] Thereby, as shown in FIG. 2 , a semiconductor element package assembly 35 including the substrate 2 , the plurality of semiconductor elements 3 , and the cured body sheet 20 can be obtained.

[0114] It should be noted that Figure 2B The semiconductor device package assembly 35 shown is not Figure 3 The semiconductor element package 5 after cutting shown and described below is specifically a state before the substrate 2 and the cured body sheet 20 are cut, that is, a state before the plurality of semiconductor elements 3 are singulated, that is, it has a plurality of semiconductor elements 3 .

[0115] Thereafter, the semiconductor element package assembly 35 is divided into individual pieces corresponding to the plurality of semiconductor elements 3 .

[0116] Specifically, first, Figure 2B As shown by the arrow, the second release sheet 16 is peeled off from the first surface 6 of the cured body sheet 20. Figure 3 As shown, the semiconductor element package assembly 35 is turned upside down and arranged to face the adsorption stage 30 .

[0117] The adsorption stage 30 has a plate shape in the surface direction and has a flat adsorption surface 31. In addition, the adsorption stage 30 has an adsorption hole 32 penetrating in the thickness direction. The upstream end of the adsorption hole 32 in the adsorption direction ( Figure 3 The suction holes 32 are arranged in a plurality of spaces in the surface direction. The suction direction downstream end portions ( Figure 3 The lower end portion of the suction surface 31 is connected to a suction device (not shown). In addition, the suction surface 31 has a larger size than the above-mentioned solidified body sheet 20.

[0118] Then, the first surface 6 of the solidified body sheet 20 in the semiconductor element package assembly 35 is brought into contact with the adsorption surface 31 of the adsorption stage 30. Specifically, the first surface 6 of the solidified body sheet 20 is brought into close contact (adsorbed) with the adsorption surface 31 of the adsorption stage 30 in such a manner as to block the upstream end of the adsorption hole 32 in the adsorption direction.

[0119] Next, the suction device is driven to reduce the pressure in the suction hole 32 (to low pressure, negative pressure, or vacuum pressure), thereby fixing the semiconductor element package assembly 35 to the adsorption stage 30 .

[0120] Next, the cured body sheet 20 and the substrate 2 around each of the plurality of semiconductor elements 3 are cut (diced) by, for example, a dicing machine 25. The dicing machine 25 enters the substrate 2 and the cured body sheet 20 from, for example, the second surface 7 of the substrate 2 toward the first surface 6 of the cured body sheet 20.

[0121] Thereafter, the singulated semiconductor element package 5 is transferred to another place using a pickup device (not shown) or the like. Specifically, the semiconductor element package 5 is pulled up from the suction stage 30 by the pickup device.

[0122] Furthermore, in the semiconductor element sealing sheet 1 , the ratio of the inorganic filler in the semiconductor element sealing sheet 1 is high, being 50% or more and 95% or less, and therefore, the toughness of the cured body sheet 20 is excellent.

[0123] Furthermore, since the ratio of the Shore D hardness of the cured body sheet 20 at 80° C. to the Shore D hardness of the cured body sheet 20 at 25° C. is less than 1.0, the cured body sheet 20 has excellent flexibility when heated.

[0124] In this way, Figure 3 As shown, the solidified body sheet 20 in the semiconductor element package assembly 35 is heated by contact with the cutting machine 25 even when fixed to the adsorption surface 31 of the adsorption platform 30. As mentioned above, the solidified body sheet 20 has excellent flexibility when heated, so damage such as breakage and cracking can be suppressed.

[0125] On the other hand, the ratio of the Shore D hardness of the cured body sheet 20 at 80°C to the Shore D hardness of the cured body sheet 20 at 25°C is 0.5 or more, so the cured body sheet 20 has excellent sealing properties. That is, when the cured body sheet 20 is heated, the decrease in the Shore D hardness is small, so the semiconductor element 3 can be reliably sealed and protected. Therefore, a semiconductor element package 5 with excellent reliability can be obtained.

[0126] <Modification>

[0127] In each of the following modifications, the same reference numerals are used for the same components and processes as those in the above-mentioned embodiment, and detailed description thereof is omitted. In addition, each modification can achieve the same effects as those in the embodiment except for special descriptions. In addition, the embodiment and the modification can be appropriately combined.

[0128] exist Figure 3 In the process of singulating the plurality of semiconductor elements 3 , the cured body sheet 20 is brought into contact with the adsorption stage 30 .

[0129] However, if Figure 4As shown, for example, the substrate 2 can also be brought into contact with the adsorption stage 30. In the process of singulating the plurality of semiconductor elements 3, the second facing surface 9 of the substrate 2 is brought into close contact with the adsorption surface 31 of the adsorption stage 30 to fix the semiconductor element package assembly 35 to the adsorption stage 30. Then, the semiconductor element package assembly 35 is singulated.

[0130] Although not shown, a single semiconductor element 3 can also be sealed using the semiconductor element sealing sheet 1. In this case, the solidified body sheet 20 obtained by sealing the single semiconductor element 3 is fixed (closely attached) using the adsorption stage 30, and the solidified body sheet 20 and the substrate 2 are processed in shape in a manner corresponding to the semiconductor element 3 using a cutting machine 25 or the like.

[0131] In addition, in one embodiment, the semiconductor element sealing sheet 1 is cited as an example of a sealing sheet to seal the semiconductor element 3, but the invention is not limited thereto. For example, although not shown, an electronic element sealing sheet for sealing other electronic elements may also be used. In this case, the electronic element sealing sheet can be used to seal the electronic element, thereby manufacturing an electronic element package.

[0132] Example

[0133] The following examples and comparative examples are shown to further specifically describe the present invention. It should be noted that the present invention is not limited to any examples and comparative examples. In addition, the specific numerical values ​​such as the mixing ratio (ratio), physical property values, and parameters used in the following description can be replaced by the upper limit (defined as "below", "less than" numerical value) or lower limit (defined as "above", "exceeding" numerical value) of the mixing ratio (ratio), physical property values, and parameters corresponding thereto recorded in the above-mentioned "specific embodiments".

[0134] The components used in Examples and Comparative Examples are shown below.

[0135] Epoxy resin: YSLV-80XY manufactured by Nippon Steel Chemical Co., Ltd. (bisphenol F type epoxy resin (bifunctional epoxy resin), epoxy equivalent 200 g / eq., softening point 80°C)

[0136] Curing agent: LVR-8210DL manufactured by Qun-Ei Chemical Co., Ltd. (novolac-type phenolic resin, epoxy resin curing agent, hydroxyl equivalent: 104 g / eq., softening point: 60°C)

[0137] Curing accelerator: 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazole) manufactured by Shikoku Chemical Industry Co., Ltd., epoxy resin curing accelerator

[0138] First filler: FB-8SM manufactured by Denka (spherical fused silica powder (inorganic filler), average particle size 15 μm)

[0139] 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.) or surface-treating SC220G-SMJ with 1 part by mass of a silane coupling agent per 100 parts by mass of SC220G-SMJ.

[0140] Thermoplastic resin: HME-2006M manufactured by Negami Industries, carboxyl-containing acrylic acid ester copolymer, weight average molecular weight: 600,000, methyl ethyl ketone solution with a solid content concentration of 20% by mass

[0141] Pigment: Mitsubishi Chemical Corporation #20 (carbon black)

[0142] Silane coupling agent: KBM-403 (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.

[0143] Examples 1 to 4 and Comparative Example 1

[0144] Each component was dissolved and dispersed in methyl ethyl ketone according to the formulation described in Table 1 to obtain a varnish. The solid content concentration of the varnish was 80% by mass.

[0145] After applying the varnish on the surface of the first release sheet 15 , it was dried at 110° C. for five minutes. Thus, a semiconductor element sealing sheet 1 having a thickness of 260 μm was manufactured. Then, the second release sheet 16 was arranged on the first surface 6 of the semiconductor element sealing sheet 1 .

[0146] Thereafter, the semiconductor element sealing sheet 1 was heated at 150° C. for one hour to prepare a cured body sheet 20 .

[0147] [physical properties]

[0148] The following physical properties were evaluated for the cured product sheet 20. The results are shown in Table 1.

[0149] (Shore D hardness)

[0150] The cured sheet 20 was processed into a shape of 10 cm in length and 10 cm in width, and the D type durometer hardness was calculated as the Shore D hardness at 25° C. and 80° C. according to JIS K 6253-3 (vulcanized rubber and thermoplastic rubber - Method for determining hardness - Part 3: Durometer hardness, 2012).

[0151] The details of the measuring device and the measuring method are as follows.

[0152] Measuring device: Hardness tester (Model: HD-1120 (spring type hardness tester), manufactured by Ueshima Manufacturing Co., Ltd.)

[0153] Measurement method: The average value of the values ​​measured 10 times using 10 samples was obtained as the Shore D hardness.

[0154] (Tensile storage elastic modulus E' and glass transition temperature Tg)

[0155] The cured body sheet 20 was processed into an outer shape of 0.1 cm in the longitudinal direction and 5 cm in the lateral direction, and the tensile storage elastic modulus E' at 25° C. and 260° C. was determined.

[0156] At the same time, the tensile loss modulus E'' was obtained, and a curve of tan δ (=E'') was obtained from the tensile storage modulus E' and the tensile loss modulus E'', and the glass transition temperature Tg was obtained as the peak value of tan δ.

[0157] The details of the measurement apparatus and measurement conditions are as follows.

[0158] Measuring device: Solid viscoelasticity measuring device (type: RSA-G2, manufactured by TA Instruments)

[0159] Mode: Stretch

[0160] Scanning temperature: 0~260℃

[0161] Frequency: 1Hz

[0162] Deformation: 0.05%

[0163] Heating speed: 10℃ / min

[0164] [Evaluation of Cured Sheet]

[0165] The following tests were performed and evaluated on the cured body sheet 20 .

[0166] (Heating damage test)

[0167] The cured body sheet 20 was processed into an outer shape of 10 cm in length and 10 cm in width, and 100 such cured body sheets 20 were prepared.

[0168] Next, 100 cured sheets 20 were aligned on a large suction table 30, heated to 80°C, and then a suction device (not shown) was driven. Then, the flexibility during heating was evaluated according to the following criteria.

[0169] ⊚: No damage such as cracking or breaking was observed in all 100 cured product sheets 20 .

[0170] ◯: Damage such as cracking or breaking was observed in one or more and two or less cured product sheets 20 .

[0171] △: Damage such as cracking and breaking was observed in 3 or more and 5 or less cured product pieces 20 .

[0172] ×: Damage such as cracking and breaking was observed in six or more cured product sheets 20 .

[0173] [Table 1]

[0174]

[0175] Unless otherwise specified in Table 1, the numerical values ​​are the blending quantities.

[0176] It should be noted that the above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and is not to be construed as limiting. Modifications of the present invention that are obvious to those skilled in the art are included in the claims described below.

Claims

1. A sealing sheet comprising a thermosetting component and an inorganic filler, The sealing sheet is characterized in that The ratio of the inorganic filler in the sealing sheet is 50% or more and 95% or less, The ratio of the Shore D hardness of the cured body sheet at 80° C. to the Shore D hardness of the cured body sheet at 25° C. of the sealing sheet as a cured product is 0.5 or more and less than 1.0, A ratio of a tensile storage modulus E' of the cured sheet at 25°C to a tensile storage modulus E' of the cured sheet at 260°C is 10 or more and 500 or less.

2. The sealing sheet according to claim 1, wherein The ratio of the inorganic filler in the sealing sheet is less than 70%.

3. The sealing sheet according to claim 1, wherein: The Shore D hardness of the cured sheet at 25° C. is 50 or more and 80 or less.

4. The sealing sheet according to claim 1, wherein: The cured sheet has a glass transition temperature Tg of 100° C. or less.

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