Sheet for sealing electronic devices and method for manufacturing electronic device package

Abstract

The present invention provides a sheet for sealing electronic devices, which is low in viscosity and can be filled with a large amount of inorganic filler. The sheet for sealing electronic devices contains an inorganic filler in an amount of 69 to 86 vol% and a silane coupling agent having a methacryloyloxy group or an acryloyloxy group, and has a minimum viscosity of 10 to 1,000,000 Pa·s.

Description

[0001] This application is a divisional application of application number 201510750350.4, entitled "Manufacturing Method of Sealing Sheet for Electronic Devices and Package for Electronic Devices". The parent application was filed on November 6, 2015, and the earliest priority date is November 7, 2014. Technical Field

[0002] This invention relates to a method for manufacturing sealing sheets for electronic devices and electronic device packages. Background Technology

[0003] In the fabrication of electronic device packages, a typical approach involves sealing one or more electronic devices, which are fixed to a substrate or the like using bumps, with a sealing resin, and then cutting the seal body in a sequence that forms a package for an electronic device unit, as needed. Sometimes, sheet-like sealing resins are used as such sealing resins (see, for example, Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2006-19714 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] One method for manufacturing the aforementioned package is to laminate sealing sheets over one or more electronic devices disposed on an adhesive substrate, and then heat-cure the sealing sheets. In packages manufactured in this way, there is a problem of warping during heat curing due to the difference in the coefficients of thermal expansion between the resin of the sealing sheet and the electronic devices.

[0009] As a method to suppress warping of the package, one approach is to increase the content of inorganic filler in the sealing sheet. This allows the coefficient of thermal expansion of the sealing sheet to approach that of the electronic device.

[0010] However, the higher the content of inorganic filler in the sealing sheet, the greater the viscosity of the sealing sheet becomes, thus creating a problem where a certain amount cannot be contained.

[0011] The present invention has been implemented in view of the above-mentioned problems, and its object is to provide a sealing sheet for electronic devices that is low in viscosity and can be filled with inorganic fillers.

[0012] Methods for solving problems

[0013] The inventors of this application discovered that the above-mentioned problems can be solved by adopting the following configuration, thereby completing the present invention.

[0014] That is, the electronic device sealing sheet involved in this invention is characterized in that,

[0015] Compounds containing methacryloyloxy or acryloyloxy groups are used as silane coupling agents.

[0016] It contains inorganic fillers in the range of 69–86% by volume.

[0017] The minimum viscosity is in the range of 10 to 1,000,000 Pa·s.

[0018] Based on the above composition, a compound containing methacryloyloxy or acryloyloxy groups that does not react with the thermosetting resin is used as a silane coupling agent. Therefore, the increase in viscosity caused by reaction with the thermosetting resin can be suppressed. Furthermore, since the increase in viscosity caused by reaction with the thermosetting resin can be suppressed, the content of inorganic fillers can be increased.

[0019] Furthermore, the presence of inorganic filler in the range of 69–86 vol% allows for a coefficient of thermal expansion close to that of electronic devices. As a result, warpage of the package can be suppressed. Moreover, the presence of inorganic filler in the range of 69–86 vol% reduces water absorption. Additionally, viscosity increases are suppressed within a minimum viscosity range of 10–1,000,000 Pa·s. Consequently, the reliability of electronic device packages manufactured using this sealing sheet can be improved.

[0020] In the above configuration, when the tensile storage modulus at 50°C is set as X and the minimum viscosity is set as Y, the X / Y ratio is preferably in the range of 15 to 100.

[0021] Based on experimental results and other in-depth research, the inventors have found that if the X / Y ratio is set to 15 or higher, it can combine operability as a sheet with the ability to follow parts during molding, resulting in a good yield rate. On the other hand, it has been found that if the X / Y ratio is set to 100 or lower, the sheet will not be too hard, thus preventing breakage and defects during molding.

[0022] In the above configuration, it is preferable that the inorganic filler has been pre-treated with the silane coupling agent.

[0023] When the surface of an inorganic filler is treated with a silane coupling agent, gas release (e.g., methanol) occurs. Therefore, if the inorganic filler is pre-treated with a silane coupling agent in a stage prior to the fabrication of the sealing sheet for the electronic device, the degree of gas release at that stage can be eliminated. As a result, the amount of gas released into the sealing sheet during its fabrication can be suppressed, and the formation of voids can be reduced.

[0024] In the above configuration, it is preferable that the inorganic filler is pre-treated with the silane coupling agent in a manner that is 0.5 to 2 parts by weight relative to 100 parts by weight of the inorganic filler.

[0025] Surface treatment of inorganic fillers using silane coupling agents can reduce the viscosity of sealing sheets for electronic devices. However, a higher amount of silane coupling agent increases the amount of gas release. Therefore, even with pre-surface treatment of the inorganic filler, gas release during the fabrication of the sealing sheet can still degrade its performance. On the other hand, a low amount of silane coupling agent cannot adequately reduce the viscosity. Therefore, by pre-surface treating the inorganic filler with 0.5 to 2 parts by weight of silane coupling agent relative to 100 parts by weight of the inorganic filler, the viscosity can be appropriately reduced while suppressing performance degradation caused by gas release.

[0026] Furthermore, the method for manufacturing the electronic device package involved in this invention includes:

[0027] The process of preparing the above-mentioned sealing sheets for electronic devices

[0028] The lamination process of stacking the sealing sheet for the electronic devices in a manner that covers one or more electronic devices disposed on the substrate, and

[0029] A sealing body forming process that cures the sealing sheet for the above-mentioned electronic device to form a sealing body.

[0030] Based on the above configuration, since the aforementioned sealing sheet for electronic devices is used, the electronic device package manufactured by this method can suppress warping. As a result, the reliability of the manufactured electronic device package can be improved. Attached Figure Description

[0031] Figure 1 This is a schematic cross-sectional view of an electronic device sealing sheet according to an embodiment of the present invention.

[0032] Figure 2A This is a schematic diagram illustrating one step of a method for manufacturing a hollow package according to an embodiment of the present invention.

[0033] Figure 2B This is a schematic diagram illustrating one step of a method for manufacturing a hollow package according to an embodiment of the present invention.

[0034] Figure 2C This is a schematic diagram illustrating one step of a method for manufacturing a hollow package according to an embodiment of the present invention. Detailed Implementation

[0035] The following embodiments illustrate the present invention in detail, but the present invention is not limited to these embodiments.

[0036] Sealing sheets for electronic components

[0037] Figure 1 This is a schematic cross-sectional view showing an electronic device sealing sheet 11 (hereinafter, also referred to simply as "sealing sheet 11") according to an embodiment of the present invention. The sealing sheet 11 is typically provided in a state where it is laminated on a support 11a such as a polyethylene terephthalate (PET) film. Furthermore, to facilitate the peeling of the sealing sheet 11, a demolding process can be performed on the support 11a.

[0038] The sealing sheet 11 uses a compound having a methacryloyloxy or acryloyloxy group as a silane coupling agent. Because a compound having a methacryloyloxy or acryloyloxy group that does not react with the thermosetting resin is used as the silane coupling agent, the increase in viscosity caused by the reaction with the thermosetting resin can be suppressed.

[0039] In this specification, "using compounds having methacryloyloxy or acryloyloxy groups as silane coupling agents" includes:

[0040] (1) Cases involving inorganic fillers containing a compound having a methacryloyloxy or acryloyloxy group pre-treated for use as a silane coupling agent, and...

[0041] (2) The sealing sheet 11 contains a compound having methacryloyloxy or acryloyloxy as a silane coupling agent.

[0042] As for the aforementioned silane coupling agents, there are no particular limitations as long as they possess methacryloxy or acryloxy groups and can undergo surface treatment with inorganic fillers. Specific examples of the aforementioned silane coupling agents include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxyoctyltrimethoxysilane, and methacryloxyoctyltriethoxysilane. Among these, 3-methacryloxypropyltrimethoxysilane is preferred from the viewpoint of reactivity and cost.

[0043] The sealing sheet 11 contains an inorganic filler.

[0044] There are no particular limitations on the aforementioned inorganic fillers, and various conventionally known fillers can be used, such as powders of quartz glass, talc, silica (fused silica, crystalline silica, etc.), alumina, aluminum nitride, silicon nitride, and boron nitride. They can be used alone or in combination of two or more. Among these, silica and alumina are preferred, and silica is more preferred, considering their ability to effectively reduce the coefficient of linear expansion.

[0045] As silica, silica powder is preferred, and molten silica powder is more preferred. Spherical molten silica powder and broken molten silica powder can be cited as molten silica powder, but from the viewpoint of flowability, spherical molten silica powder is preferred.

[0046] The sealing sheet 11 preferably contains an inorganic filler in the range of 69 to 86 vol%. The above content is preferably 75 vol% or more, more preferably 78 vol% or more. Because it contains an inorganic filler in the range of 69 to 86 vol%, the coefficient of thermal expansion can be made close to that of the SAW chip 13. As a result, warpage of the package can be suppressed. Furthermore, because it contains an inorganic filler in the range of 69 to 86 vol%, the water absorption rate can be reduced.

[0047] When the inorganic filler is silicon dioxide, its content can also be described in terms of "wt%". The silicon dioxide content in the sealing sheet 11 is preferably 80-92% by weight, more preferably 85-92% by weight.

[0048] The inorganic filler preferably has an average particle size of less than 20 μm, more preferably has an average particle size of 0.1 to 15 μm, and particularly preferably has an average particle size of 0.5 to 10 μm.

[0049] In addition, two or more inorganic fillers with different average particle sizes can be used as the aforementioned inorganic fillers. When two or more inorganic fillers with different average particle sizes are used, the phrase "the average particle size of the inorganic filler is less than 20 μm" means that the overall average particle size of the inorganic filler is less than 20 μm.

[0050] The shape of the aforementioned inorganic filler is not particularly limited and can be any shape, such as spherical (including ellipsoidal), polyhedral, prismatic, flat, or irregular. However, from the viewpoint of achieving a high degree of filling with a hollow structure and moderate fluidity, spherical shape is preferred.

[0051] The inorganic filler contained in the sealing sheet 11 preferably has two peaks in its particle size distribution as determined by laser diffraction scattering. Such an inorganic filler can be obtained, for example, by mixing two inorganic fillers with different average particle sizes. Using an inorganic filler with two peaks in its particle size distribution allows for high-density filling of the inorganic filler. As a result, the content of the inorganic filler can be further increased.

[0052] The two peaks mentioned above are not particularly limited, but it is preferred that the peak on the side with larger particle size be in the range of 3 to 30 μm and the peak on the side with smaller particle size be in the range of 0.1 to 1 μm. If the two peaks are within the above-mentioned value range, the content of inorganic filler can be further increased.

[0053] Specifically, the above particle size distribution can be obtained through the following methods.

[0054] (a) The sealing sheet 11 is placed into the crucible and heated at 700°C for 2 hours in an atmospheric atmosphere to make it ashed.

[0055] (b) Disperse the obtained ash in pure water and sonicate for 10 minutes, then determine the particle size distribution (volume basis) using a laser diffraction scattering particle size distribution measuring device (Beckman Coulter, “LS 13 320”; wet method).

[0056] Furthermore, the sealing sheet 11 consists of organic components other than inorganic fillers. All organic components are substantially burned off through the aforementioned intense heat treatment, so the resulting ash content is measured as if it were inorganic filler. Additionally, the average particle size can be calculated simultaneously with the particle size distribution.

[0057] The sealing sheet 11 preferably pre-treats the inorganic filler with the aforementioned silane coupling agent. That is, the case described in (1) above is preferred. When the surface of the inorganic filler is treated with the silane coupling agent, gas release (e.g., methanol) is generated. Therefore, if the inorganic filler is pre-treated with the silane coupling agent in the stage before the manufacture of the sealing sheet 11, the gas release at that stage can be eliminated. As a result, the amount of gas release sealed into the sheet during the manufacture of the sealing sheet 11 can be suppressed, and the generation of voids can be reduced.

[0058] When the sealing sheet 11 contains an inorganic filler that has been pre-surface-treated with a compound having a methacryloyloxy or acryloxy as a silane coupling agent (in the case of (1) above), the inorganic filler is preferably pre-surface-treated with a silane coupling agent in the form of 0.5 to 2 parts by weight relative to 100 parts by weight of the inorganic filler.

[0059] If the inorganic filler is surface-treated using a silane coupling agent, the viscosity of the sealing sheet 11 can be reduced. However, if the amount of silane coupling agent is high, the amount of gas release also increases. Therefore, even if the inorganic filler is pre-treated, the gas release generated during the manufacture of the sealing sheet 11 will cause a decrease in the performance of the sealing sheet 11. On the other hand, if the amount of silane coupling agent is low, the viscosity cannot be appropriately reduced. Therefore, if the inorganic filler is pre-treated with a silane coupling agent at a ratio of 0.5 to 2 parts by weight relative to 100 parts by weight of the inorganic filler, the viscosity can be appropriately reduced, while suppressing the performance degradation caused by gas release.

[0060] When the sealing sheet 11 contains an inorganic filler that has been pre-surface-treated with a compound having a methacryloyloxy or acryloyloxy as a silane coupling agent (as described in (1) above), and when a filler consisting of two inorganic fillers with different average particle sizes is used as the inorganic filler, it is preferable to pre-surface-treat at least the inorganic filler with the smaller average particle size with a silane coupling agent. The inorganic filler with the smaller average particle size has a larger specific surface area, thus further suppressing the increase in viscosity.

[0061] Furthermore, when using an inorganic filler made by mixing two inorganic fillers with different average particle sizes as the aforementioned inorganic filler, it is more preferable to pre-treat both the inorganic filler with the smaller average particle size and the inorganic filler with the larger average particle size with a silane coupling agent. In this case, it becomes even more effective to suppress the increase in viscosity.

[0062] When the sealing sheet 11 contains a compound having a methacryloyloxy or acryloyloxy group as a silane coupling agent (as in case (2) above), the content of the silane coupling agent in the sealing sheet 11 is preferably 0.4 to 1.8% by weight. If it is 0.4% by weight or more, the viscosity can be appropriately reduced. On the other hand, if the above content is 1.8% by weight or less, the generation of gas release can be suppressed.

[0063] The minimum viscosity Y of the sealing sheet 11 is in the range of 10 to 1,000,000 Pa·s, preferably in the range of 5,000 to 800,000 Pa·s, and more preferably in the range of 10,000 to 700,000 Pa·s. Since the minimum viscosity of the sealing sheet 11 is in the range of 10 to 1,000,000 Pa·s, viscosity increase is suppressed.

[0064] Regarding the sealing sheet 11, when the tensile storage modulus at 50°C is set as X and the minimum viscosity is set as Y, the ratio X / Y is preferably in the range of 15 to 100 (L / s), more preferably in the range of 20 to 80 (L / s), and even more preferably in the range of 30 to 60 (L / s). If the above-mentioned ratio X / Y is set to 15 or more, it can have both operability as a sheet and conformability to parts during molding, and molding can be performed with good yield. On the other hand, if the above-mentioned ratio X / Y is set to 100 or less, the sheet will not be too hard, thus preventing the sheet from cracking or breaking during molding.

[0065] The tensile storage modulus X of the sealing sheet 11 at 50°C is preferably in the range of 200,000 to 40,000,000 Pa, more preferably in the range of 500,000 to 13,000,000 Pa, and even more preferably in the range of 1,000,000 to 12,000,000 Pa. If the tensile storage modulus X is 200,000 Pa or more, it is strong as a sheet and has good operability. On the other hand, if the tensile storage modulus X is 40,000,000 Pa or less, cracking or damage during processing can be prevented.

[0066] The sealing sheet 11 preferably contains epoxy resin and phenolic resin. This provides good thermosetting properties.

[0067] There are no particular restrictions on the epoxy resin used. Various epoxy resins can be used, such as triphenylmethane type epoxy resin, cresol linear phenolic type epoxy resin, biphenyl type epoxy resin, modified bisphenol A type epoxy resin, bisphenol F type epoxy resin, modified bisphenol F type epoxy resin, dicyclopentadiene type epoxy resin, phenol linear phenolic type epoxy resin, phenoxy resin, etc. These epoxy resins can be used alone or in combination of two or more.

[0068] From the viewpoint of ensuring the toughness and reactivity of epoxy resin after curing, it is preferable to use a substance with an epoxy equivalent of 150 to 250 and a softening point or melting point of 50 to 130°C that is solid at room temperature. Among these, from the viewpoint of moldability and reliability, bisphenol F type epoxy resin, bisphenol A type epoxy resin, biphenyl type epoxy resin, etc. are preferred.

[0069] There are no particular restrictions if the phenolic resin is a substance that undergoes a curing reaction with the epoxy resin. Examples of phenolic resins that can be used include linear phenolic resins, aralkyl phenolic resins, biphenyl aralkyl resins, dicyclopentadiene-type phenolic resins, linear cresol phenolic resins, and methyl phenolic resins. These phenolic resins can be used alone or in combination of two or more.

[0070] From the viewpoint of reactivity with epoxy resins, phenolic resins with a hydroxyl equivalent of 70–250 and a softening point of 50–110°C are preferred as phenolic resins. Linear phenolic resins can be suitably used from the viewpoint of high curing reactivity and low cost. Furthermore, from the viewpoint of reliability, resins with low hygroscopicity, such as phenol aralkyl resins and biphenyl aralkyl resins, can also be suitably used.

[0071] From the viewpoint of curing reactivity, the ratio of epoxy resin to phenolic resin is preferably such that the total amount of hydroxyl groups in the phenolic resin is 0.7 to 1.5 equivalents, more preferably 0.9 to 1.2 equivalents, relative to 1 equivalent of epoxy groups in the epoxy resin.

[0072] The lower limit of the total content of epoxy resin and phenolic resin in the sealing sheet 11 is preferably 5.0% by weight or more, more preferably 7.0% by weight or more. If it is 5.0% by weight or more, good adhesion to electronic devices, substrates, etc. can be obtained. On the other hand, the upper limit of the above total content is preferably 25% by weight or less, more preferably 20% by weight or less. If it is 25% by weight or less, the moisture absorption of the sealing sheet can be reduced.

[0073] The sealing sheet 11 preferably contains a thermoplastic resin. This improves the heat resistance, flexibility, and strength of the resulting hollow sealing sheet.

[0074] Examples of thermoplastic resins 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 resins such as 6-nylon or 6,6-nylon, phenoxy resins, acrylic resins, saturated polyester resins such as PET or PBT, polyamide-imide resins, fluorinated resins, and styrene-isobutylene-styrene block copolymers. These thermoplastic resins can be used alone or in combination of two or more. Among these, acrylic resins are preferred from the viewpoint of easily obtaining flexibility and good dispersibility with epoxy resins.

[0075] There are no particular limitations on the aforementioned acrylic resins, and examples include polymers (acrylic copolymers) containing one or more straight-chain or branched alkyl groups having 30 or fewer carbon atoms, particularly 4 to 18 carbon atoms. Examples of the aforementioned alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, lauryl, tridecane, tetradecyl, stearyl, octadecyl, or dodecyl.

[0076] The glass transition temperature (Tg) of the aforementioned acrylic resin is preferably below 50°C, more preferably -70 to 20°C, and even more preferably -50 to 0°C. By setting it to below 50°C, the sheet can be made flexible.

[0077] Among the aforementioned acrylic resins, resins with a weight-average molecular weight of 50,000 or more are preferred, resins with a weight-average molecular weight of 100,000 to 2,000,000 are more preferred, and resins with a weight-average molecular weight of 300,000 to 1,600,000 are even more preferred. If the values ​​are within the above range, the viscosity and flexibility of the sealing sheet 11 can be further improved. Furthermore, the weight-average molecular weight is a value calculated from polystyrene by GPC (gel permeation chromatography).

[0078] Furthermore, there are no particular limitations on other monomers that can form the aforementioned polymers. Examples include carboxyl-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, or crotonic acid; anhydride monomers such as maleic anhydride or itaconic anhydride; 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, and 8-hydroxyethyl methacrylate. hydroxyl-containing monomers such as 10-hydroxydecyl methacrylate, 12-hydroxylaurate methacrylate, or methyl 4-hydroxymethylcyclohexyl acrylate; monomers containing sulfonic acid groups such as styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, (meth)acryloyl propylene acrylate, or (meth)acryloyloxynaphthalene sulfonic acid; or monomers containing phosphate groups such as 2-hydroxyethylacryloyl phosphate. From the viewpoint of being able to react with epoxy resin to increase the viscosity of the sealing sheet 11, monomers containing carboxyl groups, glycidyl groups (epoxy groups), or hydroxyl groups are preferred.

[0079] The content of thermoplastic resin in the sealing sheet 11 is preferably 0.5% by weight or more, more preferably 1.0% by weight or more. If the content is 0.5% by weight or more, the sealing sheet will have good flexibility and suppleness. The content of thermoplastic resin in the sealing sheet 11 is preferably 10% by weight or less, more preferably 5% by weight or less. If it is 10% by weight or less, the sealing sheet will have good adhesion to electronic devices and substrates.

[0080] The sealing sheet 11 preferably contains a curing accelerator.

[0081] As a curing accelerator, there are no particular limitations as long as it promotes the curing of epoxy resin and phenolic resin. Examples include organophosphorus compounds such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate; imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazolium and 2-phenyl-4-methyl-5-hydroxymethylimidazolium; etc. Among these, imidazole compounds are preferred because of their good reactivity and the ease with which the Tg of the cured product can be increased.

[0082] The content of the curing accelerator is preferably 0.1 to 5 parts by weight relative to the total 100 parts by weight of epoxy resin and phenolic resin.

[0083] The sealing sheet 11 may contain flame retardant components as needed. This reduces the spread of fire caused by short circuits, overheating, or other factors. Flame retardant components may include various metal hydroxides such as aluminum hydroxide, magnesium hydroxide, iron hydroxide, calcium hydroxide, tin hydroxide, and complex metal hydroxides; phosphazene-based flame retardants, etc.

[0084] The sealing sheet 11 preferably contains pigment. There are no particular limitations on the pigment, and examples include carbon black.

[0085] The pigment content in the sealing sheet 11 is preferably 0.1 to 2% by weight. If it is 0.1% by weight or more, good marking properties can be obtained. If it is 2% by weight or less, the strength of the sealed sheet after curing can be ensured.

[0086] In addition, other additives may be appropriately added to the resin composition as needed, besides the components mentioned above.

[0087] [Manufacturing method for sealing plates]

[0088] A varnish can be prepared by dissolving and dispersing the resin or the like used to form the sealing sheet 11 in a suitable solvent. This varnish is then applied to the support 11a to form a coating film of a specified thickness. The coating film is then dried under specified conditions to form the sealing sheet 11. There are no particular limitations on the coating method; examples include roller coating, screen coating, and gravure coating. Drying conditions are typically within the range of a drying temperature of 70–160°C and a drying time of 1–30 minutes. After applying the varnish to the spacer to form a coating film, the coating film can be dried under the aforementioned drying conditions to form the sealing sheet 11. The sealing sheet 11 is then bonded to the support 11a together with the spacer. In particular, when the sealing sheet 11 contains thermoplastic resins (acrylic resins), epoxy resins, or phenolic resins, these resins are completely dissolved in a solvent before coating and drying. Examples of solvents include methyl ethyl ketone, ethyl acetate, and toluene.

[0089] The thickness of the sealing sheet 11 is not particularly limited, but is, for example, 100 to 2000 μm. If it is within the above range, the electronic device can be sealed well.

[0090] The sealing sheet 11 can be a single-layer structure or a multi-layer structure formed by stacking two or more sealing sheets.

[0091] [Manufacturing method of hollow package]

[0092] The following describes the case where the SAW chip is hollowed out and sealed using the sealing sheet 11.

[0093] Figures 2A to 2C The diagrams schematically illustrate one step of a method for manufacturing a hollow package according to an embodiment of the present invention. There are no particular limitations on the hollow sealing method; conventionally known methods can be used. For example, methods such as: stacking (carrying) an uncured sealing sheet 11 onto a substrate while covering electronic devices on an adherend to maintain a hollow structure, and then curing the sealing sheet 11 to achieve sealing. There are no particular limitations on the adherend; examples include printed wiring substrates, ceramic substrates, silicon substrates, and metal substrates. In this embodiment, a hollow package is fabricated by hollowly sealing a SAW chip 13 mounted on a printed wiring substrate 12 using the sealing sheet 11. Furthermore, the SAW chip 13 refers to a chip with a SAW (Surface Acoustic Wave) filter.

[0094] (SAW chip substrate preparation process)

[0095] In the SAW chip mounting substrate preparation process, a printed wiring substrate 12 (refer to) on which multiple SAW chips 13 (SAW filters 13) are mounted is prepared. Figure 2A The SAW chip 13 can be formed by monolithically cutting a piezoelectric crystal with a specified comb-shaped electrode using known methods. Known devices such as flip-chip bonding machines and chip bonding machines can be used to mount the SAW chip 13 onto the printed wiring substrate 12. The SAW chip 13 and the printed wiring substrate 12 are electrically connected via protruding electrodes 13a, such as bumps. Furthermore, a hollow portion 14 is maintained between the SAW chip 13 and the printed wiring substrate 12 in a manner that does not impede the propagation of surface elastic waves on the surface of the SAW filter. The distance (width of the hollow portion) between the SAW chip 13 and the printed wiring substrate 12 can be appropriately set, typically around 10 to 100 μm.

[0096] (Layering process)

[0097] In the lamination process, a sealing sheet 11 is laminated onto the printed wiring substrate 12 to cover the SAW chip 13, and the sealing sheet 11 is used to seal the SAW chip 13 with resin (see reference). Figure 2B The sealing sheet 11 acts as a sealing resin to protect the SAW chip 13 and its associated components from the influence of the external environment.

[0098] There are no particular limitations on the method of laminating the sealing sheet 11 on the printed wiring substrate 12, and it can be carried out by known methods such as hot pressing or lamination. As for the hot pressing conditions, the temperature is, for example, 40 to 150°C, preferably 50 to 120°C, the pressure is, for example, 0.1 to 10 MPa, preferably 0.5 to 8 MPa, and the time is, for example, 0.3 to 10 minutes, preferably 0.5 to 5 minutes. In addition, if the sealing sheet 11 is to be better fitted and followable to the SAW chip 13 and the printed wiring substrate 12, it is preferable to pressurize under reduced pressure conditions (for example, 0.01 to 5 kPa).

[0099] (Sealing body formation process)

[0100] In the sealing body forming process, the sealing sheet 11 is heat-cured to form the sealing body 15 (see reference). Figure 2B As conditions for thermosetting treatment, the heating temperature is preferably 100°C or higher, more preferably 120°C or higher. On the other hand, the upper limit of the heating temperature is preferably 200°C or lower, more preferably 180°C or lower. The heating time is preferably 10 minutes or higher, more preferably 30 minutes or higher. On the other hand, the upper limit of the heating time is preferably 180 minutes or lower, more preferably 120 minutes or lower. Additionally, pressure can be applied as needed, preferably 0.1 MPa or higher, more preferably 0.5 MPa or higher. On the other hand, the upper limit is preferably 10 MPa or lower, more preferably 5 MPa or lower.

[0101] (Chip cutting process)

[0102] Next, the chip in the sealing body 15 can be cut (see reference). Figure 2C Thus, the hollow package 18 (electronic device package) of the SAW chip 13 unit can be obtained.

[0103] (Substrate mounting process)

[0104] As needed, a substrate mounting process can be performed to form bumps on the hollow package 18 and mount it onto another substrate (not shown). Known devices such as flip-chip bonding machines and chip bonding machines can be used for mounting the hollow package 18 onto the substrate.

[0105] In the above embodiments, the electronic device sealing sheet 11 was described as a hollow sealing sheet that can seal the electronic device while leaving a hollow portion between the adhered object and the electronic device. However, the electronic device sealing sheet of the present invention is not particularly limited as long as it can seal the electronic device. For example, it can be an electronic device sealing sheet that seals the electronic device without leaving a hollow portion between the adhered object and the electronic device.

[0106] In the above embodiments, the electronic device of the present invention has been described as a semiconductor chip with a movable part, namely SAW chip 13. However, the electronic device of the present invention is not limited to this example. For example, it can be a semiconductor chip with a pressure sensor, vibration sensor, or other MEMS (Micro Electro Mechanical Systems) as the movable part. Alternatively, it can be a semiconductor chip without a movable part. Furthermore, it can also be a capacitor, resistor, etc.

[0107] Example

[0108] Hereinafter, suitable embodiments of the present invention will be described in detail. However, unless otherwise specified, the scope of the invention is not limited to the materials, proportions, etc., described in these embodiments.

[0109] The ingredients used in the examples are described below.

[0110] Epoxy resin: YSLV-80XY (bisphenol F type epoxy resin, epoxy equivalent 200g / eq., softening point 80℃) manufactured by Nippon Steel Chemical Co., Ltd.

[0111] Phenolic resin: LVR8210DL (linear phenolic resin, hydroxyl equivalent 104 g / eq., softening point 60℃) manufactured by Chung Jung Chemical.

[0112] Thermoplastic resin: HME-2006M manufactured by Negami Kogyo Co., Ltd. (carboxyl-containing acrylate copolymer, weight average molecular weight: approximately 600,000, glass transition temperature (Tg): -35℃)

[0113] Inorganic filler A: Surface-treated FB-5SDC (average particle size 5 μm) manufactured by Denki Kagaku Kogyo Co., Ltd. with 3-methacryloyloxypropyltrimethoxysilane (product name: KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). Surface-treated with a silane coupling agent at a ratio of 1 part by weight to 100 parts by weight of inorganic filler A.

[0114] Inorganic filler B: Surface-treated SO-25R (average particle size 0.5 μm) manufactured by Admatechs with 3-methacryloyloxypropyltrimethoxysilane (product name: KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). Surface-treated with a silane coupling agent at a ratio of 1 part by weight to 100 parts by weight of inorganic filler B.

[0115] Inorganic filler C: FB-5SDC manufactured by Denki Kagaku Kogyo Co., Ltd. (average particle size 5μm, untreated).

[0116] Inorganic filler D: SO-25R manufactured by Admatechs (average particle size 0.5 μm, untreated).

[0117] Silane coupling agent: 3-methacryloyloxypropyltrimethoxysilane (product name: KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.)

[0118] Carbon black: #20 manufactured by Mitsubishi Chemical Corporation

[0119] Curing accelerator: 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazolium) manufactured by Shikoku Chemical Industry Co., Ltd.

[0120] [Examples and Comparative Examples]

[0121] According to the mixing ratios listed in Table 1, each component was dissolved and dispersed in methyl ethyl ketone as a solvent to obtain a varnish with a concentration of 90% by weight. This varnish was applied to a release film containing a 38 μm thick polyethylene terephthalate film after silicone release treatment, and then dried at 110°C for 5 minutes. This yielded a sheet with a thickness of 65 μm. Four layers of this sheet were stacked to produce a 260 μm thick hollow sealing sheet.

[0122] Table 1

[0123]

[0124] (Tensive storage modulus of elasticity at 50°C for sealing sheet)

[0125] The tensile stored elastic modulus X at 50°C of the sealing sheets prepared by the examples and comparative examples was determined using a viscoelasticity measuring apparatus (Rheometric, type: RSA-II). Specifically, the prepared sealing sheets were cut to obtain sample sizes of 30 mm in length and 5 mm in width. The test specimens were placed in a membrane tensile testing fixture, and the measurements were performed in a temperature range of -20°C to 100°C at a frequency of 1 Hz, a strain of 0.01%, and a heating rate of 10°C / min. The results are shown in Table 2.

[0126] (Determination of the minimum viscosity of sealing sheets)

[0127] The minimum viscosity of the sealing sheets prepared by the examples and comparative examples was determined using a rheometer (HAAKE, MARS III) via the parallel plate method. More specifically, the viscosity was determined at a gap of 1 mm, a parallel plate diameter of 8 mm, and a rotation speed of 5 s. -1 Viscosity was measured within the range of 50℃ to 130℃ under conditions of 0.05% strain and a heating rate of 10℃ / min. The lowest viscosity value within this range was taken as the minimum viscosity. The results are shown in Table 2.

[0128] In addition, Table 2 also shows the X / Y ratio.

[0129] (Evaluation of the flexibility and adhesion of sealing sheets)

[0130] Two plates were installed in the viscoelasticity measuring apparatus (RTA-3, manufactured by TA INSTRUMENT). A plate (25mm in diameter) was used. After securing the sealing sheet of the embodiment and comparative example to the lower plate of the two plates with double-sided tape, the upper plate (probe) was lowered in a 25°C atmosphere, thereby pressing the upper plate against the sealing sheet with a load of 100g. The load required to peel the upper plate from the sealing sheet by raising it was then measured. Loads of 5g or more were rated as ○, and loads less than 5g were rated as ×. The results are shown in Table 2.

[0131] (Evaluation of warpage after curing)

[0132] The warpage of the sealing sheets of the Examples and Comparative Examples after curing was measured as follows.

[0133] For an alumina substrate with dimensions of 100mm × 100mm and a thickness of 0.2mm, at a pressure of 0.5kgf / cm 2 A sealing sheet of the same size and thickness was pressed at 100°C for 30 seconds. After curing in an oven at 150°C for 1 hour, the maximum warpage after cooling to room temperature was measured using vernier calipers. Specifically, the sealing sheet was placed on a flat surface with the sealing sheet as the top surface, and the thickness was measured from the surface to the furthest point. The warpage was then calculated by subtracting the thickness of the alumina substrate (0.2 mm) and the thickness of the sealing sheet (0.2 mm) from the measured thickness. Cases with warpage less than 2 mm were rated as ○, and cases with warpage greater than 2 mm were rated as ×. The results are shown in Table 2.

[0134] (Evaluation of resin penetration into the hollow portion of the package)

[0135] A SAW chip mounting substrate was fabricated by mounting a SAW chip with the following specifications, which had aluminum comb-shaped electrodes, on a ceramic substrate under the following bonding conditions. The gap width between the SAW chip and the ceramic substrate was 15 μm.

[0136] <SAW chip>

[0137] Chip size: 1.2 mm square (thickness 150 μm)

[0138] Bump material: Au (height 15 μm)

[0139] Number of bumps: 6 bumps

[0140] Number of chips: 100 (10 × 10)

[0141] <Chip bonding conditions>

[0142] Equipment: Manufactured by Panasonic Electric Works Co., Ltd.

[0143] Bonding conditions: 200 °C, 3 N, 1 sec, ultrasonic output power 2 W

[0144] On the obtained SAW chip mounting substrate, each sealing sheet was attached by vacuum pressing under the heating and pressing conditions shown below.

[0145] <Attachment conditions>

[0146] Temperature: 60 °C

[0147] Pressing force: 4 MPa

[0148] Vacuum degree: 1.6 kPa

[0149] Pressing time: 1 minute

[0150] After opening to atmospheric pressure, in a hot air dryer, the sealing sheet was thermally cured under the conditions of 150 °C for 1 hour to obtain a sealed body. The substrate and the sealing resin interface of the obtained sealed body were split, and the amount of resin entering the hollow part between the SAW chip and the ceramic substrate was measured by a digital microscope (200 times magnification) manufactured by KEYENCE Corporation. Regarding the resin entry amount, the maximum distance that the resin entered the hollow part from the end of the SAW chip was measured and used as the resin entry amount. In addition, when there was no entry and the hollow part extended more outward than the SAW chip, the resin entry amount was represented by a negative sign. The case where the resin entry amount was -50 μm to 50 μm was evaluated as "○", and the case where it was less than -50 μm or greater than 50 μm was evaluated as "×". The results are shown in Table 2.

[0151] [Table 2]

[0152]

[0153] Symbol Explanation

[0154] 11. Sealing sheets (sealing sheets for electronic components)

[0155] 11a Support body

[0156] 13SAW chip

[0157] 15. Sealing body

[0158] 18 Hollow Package

Claims

1. An electronic device sealing sheet, characterized by comprising: using a compound having a methacryloyloxy group or an acryloyloxy group as a silane coupling agent, containing an inorganic filler in a range of 69% by volume to 86% by volume, the inorganic filler having an average particle diameter of 0.5 μm to 20 μm, the inorganic filler having two peaks in a particle size distribution measured by a laser diffraction scattering method, of the two peaks, a peak on a large particle diameter side being in a range of 3 μm to 30 μm, a peak on a small particle diameter side being in a range of 0.1 μm to 1 μm, the inorganic filler being surface-treated in advance with the silane coupling agent, the inorganic filler being surface-treated in advance with the silane coupling agent in a range of 0.5 parts by weight to 1 part by weight with respect to 100 parts by weight of the inorganic filler, a minimum viscosity being in a range of 10 Pa-s to 1,000,000 Pa-s.

2. The electronic device sealing sheet according to claim 1, characterized by comprising: a ratio of a tensile storage elastic modulus at 50°C to a minimum viscosity being in a range of 15 to 100.

3. A method of manufacturing an electronic device package, characterized by, including: a step of preparing the electronic device sealing sheet according to claim 1 or 2, a lamination step of laminating the electronic device sealing sheet in a manner of covering one or a plurality of electronic devices disposed on an adherend, a sealing body forming step of curing the electronic device sealing sheet to form a sealing body.

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