JP2014225635A - Hollow sealing sheet and method of producing hollow package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow sealing sheet capable of producing a hollow package having high reliability, and to provide a method of manufacturing the hollow package.SOLUTION: A hollow sealing sheet for sealing an electronic component in a hollow manner contains a resin and is controlled in resin entering property into a hollow part at 40°C or more and 100°C or less. A molding metal die having a 20 μm width slit is filled with the resin, and the amount of resin entering the slit is preferable to be 3 mm or less when the resin is pressurized for 10 minutes at pressure 10 kg/cm2 and temperature 150°C.

Description

  The present invention relates to a hollow sealing sheet and a method for manufacturing a hollow package.

  For the production of electronic component packages such as semiconductors, typically, one or more electronic components fixed to a substrate, a temporary fixing material or the like are sealed with a sealing resin, and a sealed object is provided as necessary. A procedure of dicing so as to form a package in units of electronic components is employed. As such a sealing resin, a sheet-shaped sealing resin having good handling properties is used. In addition, as a technique for increasing the blending amount of the filler in order to improve the performance of the hollow sealing sheet, a technique of blending the filler by kneading into the sealing sheet has been proposed (Patent Document 1).

JP 2013-7028 A

  In recent years, along with semiconductor packages, microelectronic components called MEMS, such as SAW (Surface Acoustic Wave) filters, CMOS (Complementary Metal Oxide Semiconductor) sensors, and acceleration sensors, are being developed. Each of these electronic components generally has a hollow structure for ensuring the propagation of surface acoustic waves, maintaining an optical system, the mobility of a movable member, and the like. When sealing, it is necessary to seal while maintaining the hollow structure so as to ensure the operation reliability of the movable member and the connection reliability of the element. The sealing sheet is required to meet the demand for a hollow package having such a hollow structure.

  The objective of this invention is providing the manufacturing method of the hollow sealing sheet which can produce a highly reliable hollow package, and a hollow package.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by adopting the following configuration, and have completed the present invention.

That is, the present invention is a hollow sealing sheet for hollow sealing electronic components,
Including resin,
Resin penetration into the hollow part is controlled at 40 ° C. or higher and 100 ° C. or lower.

  In the hollow sealing sheet, since the resin penetration into the hollow part is controlled at 40 ° C. or higher and 100 ° C. or lower, the resin penetration into the hollow part is suppressed during hollow sealing, and the hollow is highly reliable. A package can be produced.

In the hollow sealing sheet, the amount of resin entering the slit when the resin is filled in a molding die having a slit with a width of 20 μm and the resin is pressurized at a pressure of 10 kg / cm ² and a temperature of 150 ° C. for 10 minutes. Is preferably 3 mm or less. Thereby, since the resin penetration property under the heating and pressurization to a predetermined slit is suppressed, a hollow package having higher reliability can be manufactured. In addition, the measurement of the amount of resin penetration is based on description of an Example.

  In the hollow sealing sheet, it is preferable that a minimum value exists in the plot when the amount of resin entering the slit having a width of 1 μm or more and 100 μm or less is plotted against the slit width. The mechanism for the existence of such a local minimum is not clear, but is estimated as follows. For example, when the hollow encapsulating sheet contains dilatancy-providing microparticles such as inorganic fillers and elastomer particles, a dilatancy-like action works in the slit peripheral region, and the resin is prevented from entering the slit. When the slit width is sufficiently larger than the particle size of the fine particles, the dilatancy-like action is weak, and the resin easily enters the slit together with the fine particles, so that the amount of resin penetration increases. As the slit width becomes smaller, the dilatancy-like action becomes stronger and the resin entry amount becomes smaller, and the resin entry amount takes a minimum value at a certain point. When the slit width becomes a certain value or less, entry of fine particles into the slit is restricted, and only the resin component enters the slit. In the case of resin alone, the dilatancy-like action is weakened, so that the amount of resin penetration increases. When the force applied to the hollow sealing sheet is constant, the smaller the slit width is, the more the resin is pushed out into the slit, and as a result, the amount of resin entering becomes larger. In this way, it is considered that there is a minimum value in the plot of the resin penetration amount against the slit width. In addition, by utilizing this phenomenon, the composition of the hollow sealing sheet can be designed to maximize the dilatancy-like effect on the gap gap of the hollow part, and the resin entry into the hollow part is more efficiently regulated. Thus, a highly reliable hollow package can be manufactured.

  In the sealing sheet, the minimum value is preferably 2 mm or less. Thereby, resin penetration property can be suppressed more highly and the reliability of a hollow package can further be improved.

In the present invention, a laminating step of laminating the hollow sealing sheet on the electronic component so as to cover one or a plurality of electronic components while maintaining a hollow portion, and a sealing body by curing the hollow sealing sheet It is a manufacturing method of the hollow package including the sealing body formation process of forming.

  In the production method of the present invention, since the hollow sealing sheet in which the resin penetration into the hollow part is controlled is used, a highly reliable hollow package is produced as a whole while ensuring a good hollow part. Can do.

It is sectional drawing which shows typically the hollow sealing sheet which concerns on one Embodiment of this invention. It is sectional drawing which shows typically 1 process of the manufacturing method of the hollow package which concerns on one Embodiment of this invention. It is sectional drawing which shows typically 1 process of the manufacturing method of the hollow package which concerns on one Embodiment of this invention. It is sectional drawing which shows typically 1 process of the manufacturing method of the hollow package which concerns on one Embodiment of this invention. It is a SEM observation image of the cut surface of the hollow sealing sheet in the Example of this invention. It is a schematic cross section of the molding die for measuring the amount of resin entering the slit of the molding die. It is a top view of the lower metal mold | die of a shaping die. It is a schematic cross section which shows the measurement procedure for measuring the resin approach amount to the slit of a shaping die.

<< First Embodiment >>
[Hollow sealing sheet]
The hollow sealing sheet which concerns on this embodiment is demonstrated referring FIG. FIG. 1 is a cross-sectional view schematically showing a hollow sealing sheet according to an embodiment of the present invention. The hollow sealing sheet 11 is typically provided in a state of being laminated on a support 11a such as a polyethylene terephthalate (PET) film. In addition, in order to peel the hollow sealing sheet 11 easily, the mold release process may be performed to the support body 11a.

  As for the hollow sealing sheet 11, resin penetration property to the hollow part 14 (refer FIG. 2A) is controlled in 40 to 100 degreeC. Therefore, in the hollow package 18 (see FIG. 2C) obtained using the hollow sealing sheet 11, the hollow portion 14 can be secured, and the operation reliability and connection reliability of the electronic components can be obtained at a high level. .

The amount of resin entering the slit when filling the molding die having a slit of 20 μm in width with the resin for forming the hollow sealing sheet 11 and pressurizing the resin for 10 minutes at a pressure of 10 kg / cm ² and a temperature of 150 ° C. It is preferably 3 mm or less, and more preferably 2 mm or less. By setting the resin penetration under heating and pressurization within the above range, a hollow package having higher reliability can be manufactured.

  In the hollow sealing sheet 11, when the amount of resin entering a slit having a width of 1 μm or more and 100 μm or less is plotted against the slit width, it is preferable that a minimum value exists in the plot. Thereby, the composition design of the hollow sealing sheet for minimizing the amount of resin entering the hollow portion is possible, and a more reliable hollow package can be manufactured.

  In the sealing sheet, the minimum value is preferably 2 mm or less, and more preferably 1 mm or less. Thereby, resin penetration property can be suppressed more highly and the reliability of a hollow package can further be improved.

  The linear expansion coefficient at 20 ° C. after thermosetting the hollow sealing sheet at 150 ° C. for 1 hour is preferably 15 ppm / K or less, and more preferably 10 ppm / K or less. Thereby, the curvature in a hollow package can be suppressed favorably. The measuring method of the linear expansion coefficient is as follows. The hollow sealing sheet before hardening of width 4.9mm, length 25mm, and thickness 0.2mm is hardened at 150 degreeC for 1 hour. The cured resin sheet is set in TMA8310 (manufactured by Rigaku Corporation), and the linear expansion coefficient is measured at a tensile load of 4.9 mN and a temperature increase rate of 10 ° C./min.

  The resin composition forming the hollow sealing sheet is not particularly limited as long as it can suitably impart the above-described characteristics and can be used for resin sealing of electronic components such as semiconductor chips. Especially, it is preferable that the control material which can control the resin flow in the hollow part vicinity is included. As such a regulation material, high viscosity substances such as elastomers, high viscosity epoxy resins, and high viscosity phenol resins, and dilatancy imparting fine particles such as inorganic fillers can be suitably used.

The viscosity of the high-viscosity material may be appropriately set in consideration of the degree of regulation of resin flow, workability, and the like, but is preferably 2000 Pa · s to 30000 Pa · s at 80 ° C., preferably 5000 Pa · s to 25000. More preferred. The viscosity can be measured by a parallel plate method using a viscoelasticity measuring device ARES manufactured by TA Instruments. More specifically, by measuring the viscosity in the range of 50 ° C. to 200 ° C. under the conditions of a gap of 100 μm, a rotating plate diameter of 20 mm, and a rotational speed of 10 s ⁻¹ , and reading the viscosity at 80 ° C. obtained at that time can get.

As specific components, epoxy resin compositions containing the following components A to E are preferred.
A component: Epoxy resin B component: Phenol resin C component: Elastomer D component: Inorganic filler E component: Curing accelerator

(A component)
It does not specifically limit as an epoxy resin (A component) as a thermosetting resin. For example, triphenylmethane type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, modified bisphenol A type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, modified bisphenol F type epoxy resin, dicyclopentadiene type Various epoxy resins such as an epoxy resin, a phenol novolac type epoxy resin, and a phenoxy resin can be used. These epoxy resins may be used alone or in combination of two or more.

  From the viewpoint of ensuring the toughness after curing of the epoxy resin and the reactivity of the epoxy resin, those having an epoxy equivalent of 150 to 250 and a softening point or melting point of 50 to 130 ° C. are preferably solid, and in particular, from the viewpoint of reliability. Therefore, triphenylmethane type epoxy resin, cresol novolac type epoxy resin, and biphenyl type epoxy resin are preferable.

  Also, from the viewpoint of low stress, a modified bisphenol A type epoxy resin having a flexible skeleton such as an acetal group or a polyoxyalkylene group is preferable, and a modified bisphenol A type epoxy resin having an acetal group is in a liquid state and is easy to handle. Therefore, it can be particularly preferably used.

  Increasing the weight average molecular weight of the epoxy resin also increases the viscosity, and the epoxy resin itself can act as the regulating material. Although it will not specifically limit if it is a grade which can act as said control material as a weight average molecular weight, 150 or more are preferable and 300 or more are more preferable.

  The content of the epoxy resin (component A) is preferably set in the range of 1 to 10% by weight with respect to the entire epoxy resin composition.

(B component)
The phenol resin (component B) is not particularly limited as long as it can be used as a thermosetting resin and causes a curing reaction with the epoxy resin (component A). For example, a phenol novolak resin, a phenol aralkyl resin, a biphenyl aralkyl resin, a dicyclopentadiene type phenol resin, a cresol novolak resin, a resole resin, or the like is used. These phenolic resins may be used alone or in combination of two or more.

  From the viewpoint of reactivity with the epoxy resin (component A), it is preferable to use a phenolic resin having a hydroxyl equivalent weight of 70 to 250 and a softening point of 50 to 110 ° C., among which the curing reactivity is high. A phenol novolac resin can be preferably used. From the viewpoint of reliability, low hygroscopic materials such as phenol aralkyl resins and biphenyl aralkyl resins can also be suitably used.

  From the viewpoint of curing reactivity, the blending ratio of the epoxy resin (component A) and the phenol resin (component B) is a hydroxyl group in the phenol resin (component B) with respect to 1 equivalent of the epoxy group in the epoxy resin (component A). It is preferable to mix | blend so that it may become 0.7-1.5 equivalent, More preferably, it is 0.9-1.2 equivalent.

  When the weight average molecular weight of the phenol resin is increased, the viscosity increases, and the phenol resin itself can act as the regulating material. Although it will not specifically limit if it is a grade which can act as said control material as a weight average molecular weight, 150 or more are preferable and 300 or more are more preferable.

In addition, in this specification, the measuring method of a weight average molecular weight can be measured with the following method. A sample is dissolved in THF at 0.1 wt%, and the weight average molecular weight is measured by polystyrene conversion using GPC (gel permeation chromatography). Detailed measurement conditions are as follows.
<Measurement conditions of weight average molecular weight>
GPC device: Tosoh HLC-8120GPC
Column: manufactured by Tosoh Corporation, (GMHHR-H) + (GMHHR-H) + (G2000HHR)
Flow rate: 0.8mL / min
Concentration: 0.1 wt%
Injection volume: 100 μL
Column temperature: 40 ° C
Eluent: THF

(C component)
As an elastomer (C component) used with an epoxy resin (A component) and a phenol resin (B component), various acrylic copolymers, rubber components, etc. can be used, for example. It is preferable that a rubber component is included from the viewpoint that the dispersibility in the epoxy resin (component A) and the heat resistance, flexibility, and strength of the resulting hollow sealing sheet can be improved. Such a rubber component is preferably at least one selected from the group consisting of butadiene rubber, styrene rubber, acrylic rubber, and silicone rubber. These may be used alone or in combination of two or more. By including an elastomer that is a high-viscosity substance, resin intrusion into the hollow portion can be suitably restricted.

  In the hollow sealing sheet 11, elastomer domains are dispersed, and the maximum domain diameter is preferably 20 μm or less. Thereby, the elastomer functions as fine particles having an action (dilatancy-like action) for regulating the flow of the resin in the vicinity of the hollow portion, and the resin entry into the hollow portion can be more efficiently suppressed. The elastomer may be locally aggregated or agglomerated, but it is preferable that the elastomer is uniformly dispersed as a whole from the viewpoint of dilatancy-like action. Although the upper limit of the maximum diameter of the domain is not particularly limited as long as it is 20 μm or less, it is preferably 15 μm or less, and more preferably 10 μm or less. Further, the lower limit of the maximum diameter of the domain is preferably 0.1 μm or more, and more preferably 0.3 μm or more, from the viewpoint of physical limitation of miniaturization and imparting flexibility.

  The content of the elastomer (component C) is preferably 1.0 to 3.5% by weight of the entire epoxy resin composition, and more preferably 1.5 to 3% by weight. If the content of the elastomer (component C) is less than 1.0% by weight, it becomes difficult to obtain the flexibility and flexibility of the hollow sealing sheet 11, and further the resin sealing that suppresses the warpage of the hollow sealing sheet It will also be difficult. Conversely, when the content exceeds 3.5% by weight, the melt viscosity of the hollow sealing sheet 11 is increased and the embedding property of the electronic component is lowered, and the strength and heat resistance of the cured body of the hollow sealing sheet 11 are reduced. Tend to decrease.

  The weight ratio of the elastomer (component C) to the epoxy resin (component A) (weight of component C / weight of component A) is preferably set in the range of 0.5 to 1.5. When the weight ratio is less than 0.5, it becomes difficult to control the fluidity of the hollow sealing sheet 11, while when it exceeds 1.5, the adhesiveness of the hollow sealing sheet 11 to electronic components is inferior. This is because there is a tendency.

The ratio Ee / Et of the elastic modulus Ee of the elastomer at 60 ° C. to the elastic modulus Et of the thermosetting resin is preferably 5 × 10 ⁻⁵ or more and 1 × 10 ⁻² or less, and preferably 1 × 10 ^−4. It is preferably 5 × 10 ⁻³ or less. Thereby, at the time of kneading in the production process of the hollow sealing sheet, the shear stress from the kneading member and the thermosetting resin effectively acts on the elastomer, and the miniaturization of the elastomer can be promoted. In addition, the measuring method of the said tensile elasticity modulus Ee and Et can be performed in the following procedures. Each sheet of elastomer and thermosetting resin is cut into a strip shape having a thickness of 200 μm, a length of 400 mm, and a width of 10 mm with a cutter knife to obtain a measurement sample. Using this measurement sample, a solid viscoelasticity measuring device (RSAIII, manufactured by Rheometric Scientific) under a condition of a frequency of 1 Hz and a heating rate of 10 ° C./min, a tensile elastic modulus at −50 to 300 ° C., And measure the loss modulus. The value of the tensile modulus at 60 ° C. at the time of this measurement is read to obtain the target tensile modulus Ee and Et.

(D component)
The inorganic filler (component D) is not particularly limited, and various conventionally known fillers can be used. For example, quartz glass, talc, silica (fused silica, crystalline silica, etc.), alumina, nitriding Examples thereof include aluminum, silicon nitride, and boron nitride powders. These may be used alone or in combination of two or more. By including the inorganic filler, the dilatancy-like action in the vicinity of the hollow portion can be more efficiently imparted to the hollow sealing sheet.

  Among these, the silica powder reduces the internal stress by reducing the coefficient of thermal expansion of the cured epoxy resin composition, and as a result, the warp of the hollow sealing sheet 11 after sealing the electronic component can be suppressed. It is preferable to use a fused silica powder among the silica powders. Examples of the fused silica powder include spherical fused silica powder and crushed fused silica powder. From the viewpoint of fluidity, it is particularly preferable to use a spherical fused silica powder. Among them, those having an average particle diameter in the range of 54 μm or less are preferably used, those in the range of 0.1 to 30 μm are more preferable, and those in the range of 0.5 to 20 μm are particularly preferable.

  The average particle diameter can be derived by using a sample arbitrarily extracted from the population and measuring it using a laser diffraction / scattering particle size distribution measuring apparatus.

The content of the inorganic filler (component D) is preferably 70 to 90% by volume of the entire epoxy resin composition (81 to 94% by weight because the specific gravity is 2.2 g / cm ³ in the case of silica particles). More preferably, it is 74 to 85% by volume (84 to 91% by weight in the case of silica particles), and still more preferably 76 to 83% by volume (85 to 90% by weight in the case of silica particles). When the content of the inorganic filler (D component) is less than 70% by volume, the linear expansion coefficient of the cured product of the epoxy resin composition increases, and thus the warpage of the hollow sealing sheet 11 tends to increase. On the other hand, since the softness | flexibility and fluidity | liquidity of the hollow sealing sheet 11 will worsen when the said content exceeds 90 volume%, the tendency for adhesiveness with an electronic component to fall is seen.

(E component)
The curing accelerator (component E) is not particularly limited as long as it allows curing of the epoxy resin and the phenol resin, but from the viewpoint of curability and storage stability, triphenylphosphine or tetraphenylphosphonium tetraphenyl. Organic phosphorus compounds such as borates and imidazole compounds are preferably used. These curing accelerators may be used alone or in combination with other curing accelerators.

  It is preferable that content of a hardening accelerator (E component) is 0.1-5 weight part with respect to a total of 100 weight part of an epoxy resin (A component) and a phenol resin (B component).

(Other ingredients)
In addition to the A component to the E component, a flame retardant component may be added to the epoxy resin composition. As the flame retardant composition, various metal hydroxides such as aluminum hydroxide, magnesium hydroxide, iron hydroxide, calcium hydroxide, tin hydroxide, and complex metal hydroxide can be used.

  The average particle diameter of the metal hydroxide is preferably 1 to 10 μm, more preferably 2 to 5 μm, from the viewpoint of ensuring appropriate fluidity when the epoxy resin composition is heated. It is. When the average particle size of the metal hydroxide is less than 1 μm, it becomes difficult to uniformly disperse in the epoxy resin composition, and the fluidity during heating of the epoxy resin composition tends to be insufficient. Moreover, since the surface area per addition amount of a metal hydroxide (E component) will become small when an average particle diameter exceeds 10 micrometers, the tendency for a flame-retardant effect to fall is seen.

  As the flame retardant component, a phosphazene compound can be used in addition to the metal hydroxide. As phosphazene compounds, for example, SPR-100, SA-100, SP-100 (above, Otsuka Chemical Co., Ltd.), FP-100, FP-110 (above, Fushimi Pharmaceutical Co., Ltd.) and the like are available as commercial products. is there.

The phosphazene compound represented by the formula (1) or the formula (2) is preferable from the viewpoint of exhibiting a flame retardant effect even in a small amount, and the content of phosphorus element contained in these phosphanzene compounds is 12% by weight or more. Is preferred.
(In the formula (1), n is an integer of 3 to 25, R ¹ and R ² are the same or different and are selected from the group consisting of an alkoxy group, a phenoxy group, an amino group, a hydroxyl group and an allyl group. A monovalent organic group having
(In the formula (2), n and m are each independently an integer of 3 to 25. R ³ and R ⁵ are the same or different and are composed of an alkoxy group, a phenoxy group, an amino group, a hydroxyl group and an allyl group. R ⁴ is a divalent organic group having a functional group selected from the group consisting of an alkoxy group, a phenoxy group, an amino group, a hydroxyl group and an allyl group. .)

Moreover, it is preferable to use the cyclic phosphazene oligomer represented by Formula (3) from a viewpoint of stability and suppression of void formation.
(In Formula (3), n is an integer of 3 to 25, and R ⁶ and R ⁷ are the same or different and are hydrogen, a hydroxyl group, an alkyl group, an alkoxy group, or a glycidyl group.)

  As the cyclic phosphazene oligomer represented by the above formula (3), for example, FP-100, FP-110 (above, Fushimi Pharmaceutical Co., Ltd.) and the like are commercially available.

  The content of the phosphazene compound includes the epoxy resin (component A), phenol resin (component B), elastomer (component D), curing accelerator (component E) and phosphazene compound (other components) contained in the epoxy resin composition. It is preferable that it is 10 to 30 weight% of the whole organic component containing. That is, when the content of the phosphazene compound is less than 10% by weight of the whole organic component, the flame retardancy of the hollow sealing sheet 11 is lowered and the unevenness tracking with respect to the adherend (for example, a substrate mounted with an electronic component) Tend to be reduced and voids tend to occur. When the content exceeds 30% by weight of the whole organic component, tackiness is likely to occur on the surface of the hollow sealing sheet 11, and workability tends to be lowered, such as difficulty in alignment with the adherend.

  Moreover, the said metal hydroxide and a phosphazene compound can be used together, and the hollow sealing sheet 11 excellent in the flame retardance can also be obtained, ensuring the flexibility required for sheet sealing. By using both in combination, sufficient flame retardancy when only the metal hydroxide is used and sufficient flexibility can be obtained when only the phosphazene compound is used.

  Among the above flame retardants, it is difficult to form organic materials from the viewpoints of deformability of the hollow sealing sheet during molding of resin sealing, followability to unevenness of electronic parts and adherends, and adhesion to electronic parts and adherends. It is desirable to use a flame retardant, and a phosphazene flame retardant is particularly preferably used.

  In addition to the above components, the epoxy resin composition can be appropriately mixed with other additives such as a pigment including carbon black as necessary.

(Method for producing hollow sealing sheet)
A method for producing the hollow sealing sheet will be described below. The manufacturing method of the hollow sealing sheet of this embodiment includes the kneading | mixing process which prepares the kneaded material containing an elastomer, and the shaping | molding process which shape | molds the said kneaded material in a sheet form and obtains a hollow sealing sheet.

(Kneading process)
First, an epoxy resin composition is prepared by mixing the above-described components. The mixing method is not particularly limited as long as each component is uniformly dispersed and mixed. Then, a kneaded material is prepared by kneading each compounding component including the elastomer directly with a kneader or the like. At this time, it is preferable to knead so that the elastomer of the hollow sealing sheet is dispersed in a domain shape and the maximum diameter of the domain is 20 μm or less.

  Specifically, the above components A to E and, if necessary, each component of other additives are mixed using a known method such as a mixer, and then kneaded to prepare a kneaded product. The method of melt kneading is not particularly limited, and examples thereof include a method of melt kneading with a known kneader such as a mixing roll, a pressure kneader, or an extruder. As such a kneader, for example, a kneading screw having a portion in which the protruding amount of the screw blade from the screw shaft in a part of the axial direction is smaller than the protruding amount of the screw blade of the other portion or the shaft A kneader equipped with a kneading screw having no screw blades in a part of the direction can be suitably used. Low shear force and low agitation in the part where the protruding amount of the screw wing is small or where there is no screw wing increases the compression rate of the kneaded product, and it is possible to eliminate the trapped air and generate pores in the obtained kneaded product Can be suppressed.

  The kneading conditions are not particularly limited as long as the temperature is equal to or higher than the softening point of each component described above. For example, when considering the thermosetting property of 30 to 150 ° C. and the epoxy resin, preferably 40 to 140 ° C., more preferably It is 60-120 degreeC, and time is 1 to 30 minutes, for example, Preferably it is 5 to 15 minutes. Thereby, a kneaded material can be prepared.

  When a kneader is used for kneading, the ratio r / t of the kneading rotation speed r (rpm) to the kneading treatment amount t (kg / hr) is preferably 60 or more, and more preferably 70 or more. When the ratio r / t is 60 or more, sufficient shear stress is applied to the kneaded raw material containing the elastomer, and the miniaturization of the elastomer can be promoted efficiently. The kneading rotation speed r (rpm) is preferably 200 to 1000 rpm, and the kneading throughput t (kg / hr) is preferably 3 to 20 kg / hr.

(Molding process)
The hollow encapsulated sheet 11 can be obtained by forming the obtained kneaded material into a sheet by extrusion molding. Specifically, the hollow encapsulating sheet 11 can be formed by extrusion molding without cooling the kneaded product after melt-kneading while keeping the high temperature state. Such an extrusion method is not particularly limited, and examples thereof include a T-die extrusion method, a roll rolling method, a roll kneading method, a co-extrusion method, and a calendar molding method. The extrusion temperature is not particularly limited as long as it is equal to or higher than the softening point of each component described above, but considering the thermosetting property and moldability of the epoxy resin, for example, 40 to 150 ° C, preferably 50 to 140 ° C, Preferably it is 70-120 degreeC. Thus, the hollow sealing sheet 11 can be formed.

  Although the thickness of the hollow sealing sheet 11 is not specifically limited, It is preferable that it is 100-2000 micrometers. Within the above range, the electronic component can be satisfactorily sealed. Further, by making the resin sheet thin, the amount of heat generation can be reduced, and curing shrinkage hardly occurs. As a result, the amount of package warpage can be reduced, and a more reliable hollow package can be obtained.

  The hollow sealing sheet thus obtained may be used by being laminated so as to have a desired thickness if necessary. That is, the hollow sealing sheet may be used in a single-layer structure, or may be used as a laminate formed by laminating two or more multilayer structures.

[Method of manufacturing hollow package]
Next, the manufacturing method of the hollow package based on this embodiment using the said hollow sealing sheet is demonstrated, referring FIG. 2A to 2C are cross-sectional views schematically showing one step of the method for manufacturing the hollow package according to the embodiment of the present invention. In this embodiment, an electronic component mounted on a substrate is hollow sealed with a hollow sealing sheet to produce a hollow package. In the present embodiment, the SAW filter is used as the electronic component and the printed wiring board is used as the adherend, but other elements may be used. For example, an element having a movable part such as a capacitor, a sensor device, a light emitting element, and a vibration element as an electronic component and requiring a hollow part, and a lead frame, a tape carrier, etc. can be used as an adherend. Even if any element is used, a high degree of protection by resin sealing of the electronic component can be achieved.

(SAW chip mounting substrate preparation process)
In the SAW chip mounting board preparing step, a printed wiring board 12 on which a plurality of SAW chips 13 are mounted is prepared (see FIG. 2A). The SAW chip 13 can be formed by dicing a piezoelectric crystal on which a predetermined comb-shaped electrode is formed by a known method. For mounting the SAW chip 13 on the printed wiring board 12, a known device such as a flip chip bonder or a die bonder can be used. The SAW chip 13 and the printed wiring board 12 are electrically connected via protruding electrodes 13a such as bumps. Further, a hollow portion 14 is maintained between the SAW chip 13 and the printed wiring board 12 so as not to inhibit the propagation of surface acoustic waves on the surface of the SAW chip. The distance between the SAW chip 13 and the printed wiring board 12 is determined by the specifications of each element, and is generally about 15 to 50 μm.

(Sealing process)
In the sealing step, the hollow sealing sheet 11 is laminated on the printed wiring board 12 so as to cover the SAW chip 13, and the SAW chip 13 is resin-sealed with the hollow sealing sheet (see FIG. 2B). This hollow sealing sheet 11 functions as a sealing resin for protecting the SAW chip 13 and its accompanying elements from the external environment.

  In the present embodiment, by adopting the hollow sealing sheet 11, the SAW chip 13 can be embedded simply by sticking on the printed wiring board 12 to the coating of the SAW chip 13, thereby improving the production efficiency of the hollow package. be able to. In this case, the hollow sealing sheet 11 can be laminated on the printed wiring board 12 by a known method such as hot pressing or laminator. As hot press conditions, the temperature is, for example, 40 to 100 ° C., preferably 50 to 90 ° C., the pressure is, for example, 0.1 to 10 MPa, preferably 0.5 to 8 MPa, and the time For example, 0.3 to 10 minutes, preferably 0.5 to 5 minutes. Further, in consideration of improvement in adhesion and followability of the hollow sealing sheet 11 to the SAW chip 13 and the printed wiring board 12, it is preferable to press under reduced pressure conditions (for example, 0.1 to 5 kPa). .

  In the hollow sealing sheet 11, since the fine domains of the elastomer are dispersed, the resin component is prevented from entering the hollow portion 14, and the operation reliability and connection reliability of the SAW chip 13 can be improved.

(Sealing body forming process)
In the sealing body forming step, the hollow sealing sheet is thermoset to form the sealing body 15 (see FIG. 2B). The conditions of the thermosetting treatment of the hollow sealing sheet are preferably 100 to 200 ° C., more preferably 120 to 180 ° C. as the heating temperature, and preferably 10 to 180 minutes, more preferably 30 to 120 minutes as the heating time. You may pressurize as needed. In the pressurization, preferably 0.1 MPa to 10 MPa, more preferably 0.5 MPa to 5 MPa can be employed.

(Dicing process)
Subsequently, dicing of the sealing body 15 including elements such as the hollow sealing sheet 11, the printed wiring board 12, and the SAW chip 13 may be performed (see FIG. 2C). Thereby, the hollow package 18 in the SAW chip 13 unit can be obtained. Dicing is usually performed after fixing the sealing body 15 with a conventionally known dicing sheet.

(Board mounting process)
If necessary, it is possible to perform a substrate mounting process in which rewiring and bumps are formed on the hollow package 18 obtained above and mounted on a separate substrate (not shown). For mounting the hollow package 18 on the substrate, a known device such as a flip chip bonder or a die bonder can be used.

<< Second Embodiment >>
In the first embodiment, each compounding component is kneaded with a kneader or the like to prepare a kneaded product, and the kneaded product is extruded to form a sheet. On the other hand, in this embodiment, the varnish which melt | dissolved or disperse | distributed each component in the organic solvent etc. is applied, and it forms in a sheet form. In the coating method, since the sheet can be formed in a state where the elastomer is dissolved or dispersed in a solvent or the like, the domain size of the elastomer can be miniaturized.

  As a specific production procedure using a varnish, the above components A to E and, if necessary, other additives are appropriately mixed according to a conventional method, and uniformly dissolved or dispersed in an organic solvent to prepare a varnish. Subsequently, the hollow sealing sheet 11 can be obtained by apply | coating the said varnish on support bodies, such as polyester, and making it dry. If necessary, a release sheet such as a polyester film may be bonded to protect the surface of the hollow sealing sheet. The release sheet peels at the time of sealing.

  The organic solvent is not particularly limited, and various conventionally known organic solvents such as methyl ethyl ketone, acetone, cyclohexanone, dioxane, diethyl ketone, toluene, and ethyl acetate can be used. These may be used alone or in combination of two or more. In general, it is preferable to use an organic solvent so that the solid content concentration of the varnish is in the range of 30 to 95% by weight.

  Although the thickness of the sheet after drying the organic solvent is not particularly limited, it is usually preferably set to 5 to 100 μm, more preferably 20 to 70 μm, from the viewpoint of uniformity of thickness and the amount of residual solvent. is there.

  Hereinafter, preferred embodiments of the present invention will be described in detail by way of example. However, the materials, blending amounts, and the like described in this example are not intended to limit the scope of the present invention only to those unless otherwise specified. The term “parts” means parts by weight.

[Example 1]
(Preparation of hollow sealing sheet)
By blending the following components with a mixer, using a twin-screw kneader, kneading rotation speed is 300 rpm, kneading treatment amount is 5 kg / hr, melt kneading at 110 ° C. for 10 minutes, and then extruding from a T die, A hollow sealing sheet having a thickness of 200 μm was produced.

Epoxy resin: Bisphenol F type epoxy resin (manufactured by Nippon Steel Chemical Co., Ltd., YSLV-80XY (epochine equivalent 200 g / eq. Softening point 80 ° C.)) 3.4 parts Phenol resin: phenol resin having biphenylaralkyl skeleton (Maywa) Manufactured by Kasei Co., Ltd., MEH-7851-SS (hydroxyl equivalent: 203 g / eq., Softening point: 67 ° C.)) 3.6 parts Elastomer: (Mitsubrene C-132E manufactured by Mitsubishi Rayon Co., Ltd.) 2.3 parts Inorganic filler: spherical melting Silica (manufactured by Denki Kagaku Kogyo Co., Ltd., FB-9454FC) 87.9 parts Silane coupling agent: Epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-803) 0.5 part Carbon black (Mitsubishi Chemical) MA600) 0.1 parts Flame retardant: (FP-100, Fushimi Pharmaceutical Co., Ltd.) 1.8 parts Curing accelerator: 0.4 part of imidazole catalyst (manufactured by Shikoku Kasei Kogyo Co., Ltd., 2PHZ-PW)

[Example 2]
A hollow sealing sheet was produced in the same manner as in Example 1 except that the kneading amount was 3.5 kg / hr.

[Example 3]
A hollow sealing sheet was produced in the same manner as in Example 1 except that the kneading rotation speed was 500 rpm.

[Example 4]
A hollow sealing sheet was produced in the same manner as in Example 1 except that the kneading rotation speed was 1000 rpm.

[Example 5]
The same components as in Example 1 were dissolved or dispersed in a 1: 1 mixed solvent of methyl ethyl ketone and toluene at the same blending amount to prepare a varnish having a solid content of 40% by weight.

  On the PET film subjected to the mold release treatment, the varnish was applied so that the thickness of the coating film after drying the solvent was 50 μm, and then the drying condition was 120 ° C. for 3 minutes to dry the coating film. A resin sheet having a thickness of 50 μm was obtained. The obtained resin sheet was laminated using a laminator to a thickness of 200 μm to produce a hollow sealing sheet having a thickness of 200 μm.

[Comparative Example 1]
A hollow sealing sheet was produced in the same manner as in Example 1 except that the kneading rotation speed was 100 rpm.

[Comparative Example 2]
A hollow sealing sheet was produced in the same manner as in Example 1 except that the kneading rotation speed was 50 rpm.

(Evaluation of flexibility of hollow sealing sheet)
The sealing sheets of the examples and comparative examples were cut into a width of 60 mm and a length of 60 mm, gripped at both ends (sides opposed to each other in plan view) of the hollow sealing sheet, and slowly bent by 90 ° to be flexible. Was evaluated according to the following criteria. The results are shown in Table 1.
○: No cracking even when bent 90 °.
Δ: Cracked when bent at 90 °.
X: Cracked when bent at 90 °.

(Observation of elastomer domains)
The produced hollow sealing sheet was heat-cured at 150 ° C. for 1 hour and gradually cooled to room temperature, and then the obtained cured product was cut with a cutter. The cut surface was polished by a Buhler automatic polishing apparatus, and the cut surface after polishing was observed with SEM (2000 times). In FIG. 3, the SEM observation image of the cut surface of the hollow sealing sheet of Example 1 is shown. A region shown in black in the SEM observation image is an elastomer domain. Next, 50 elastomer domains shown in black were selected at random, and their maximum diameters were measured and averaged to obtain the maximum domain diameter. SEM observation and measurement of the maximum diameter were similarly performed for other Examples 2 to 5 and Comparative Examples 1 and 2. The results of the maximum diameter measurement are shown in Table 1.

(Measurement of resin ingress with a molding die with slits)
Using the molding die with slits shown in FIGS. 4A to 4C, the amount of resin entering the slit was measured. As shown in FIG. 4A, the molding die 100 includes a lower die 110 having a U-shaped cross section having a rising portion on the outer peripheral portion of the disk, and a disk-like upper die 120. A slit S and a cavity for receiving the resin 200 are provided between the upper mold 120 and the upper mold 120. At the center of the upper mold 120, an inlet O for a resin 200 as a measurement sample is provided. As shown in FIG. 4B, a plurality of grooves 111 cut from the upper surface at a predetermined depth are provided on the upper surface of the rising portion of the lower mold 110 in plan view. The depth of cut of each groove 111 is such a value that a predetermined width of the slit S can be obtained when combined with the upper mold 120.

  As an actual measurement procedure of the resin ingress amount, as shown in FIG. 4C, after the resin 200 is introduced into the molding die 100 from the insertion port O, the pressure rod 130 is inserted into the insertion port O. A procedure was adopted in which when the entire molding die 100 is heated and pressurized with the rod 130, the evaluation is based on the degree to which the resin 200 has entered the slit S. At this time, the distance L from the inner peripheral end of the slit S to the maximum arrival point of the resin 200 was measured as the resin ingress amount. The measurement conditions are shown below, and the results are shown in Table 1.

<Measurement conditions>
Heating temperature: 150 ° C
Pressure: 10 kg / cm ²
Pressurization time: 10 minutes Slit width: 1 μm, 5 μm, 10 μm, 20 μm, 50 μm

(Evaluation of resin penetration into package hollow)
A SAW chip mounting substrate in which a SAW chip having the following specifications on which an aluminum comb electrode was formed was mounted on a glass substrate under the following bonding conditions was produced.

<SAW chip>
Chip size: 1.4 × 1.1mm □ (thickness 150μm)
Bump material: Au Height 30μm
Number of bumps: 6 bumps Number of chips: 100 (10 x 10)

<Bonding conditions>
Equipment: manufactured by Panasonic Electric Works Co., Ltd. Bonding conditions: 200 ° C., 3N, 1 sec (ultrasound output 2W)

  Each hollow sealing sheet was affixed on the obtained SAW chip mounting substrate by a vacuum press under the heating and pressing conditions shown below.

<Paste conditions>
Temperature: 60 ° C
Applied pressure: 4 MPa
Degree of vacuum: 1.6 kPa
Press time: 1 minute

After opening to atmospheric pressure, the hollow sealing sheet was thermoset in a hot air dryer at 150 ° C. for 1 hour to obtain a sealed body. The amount of resin entering the hollow portion between the SAW chip and the glass substrate was measured from the glass substrate side with an electron microscope (manufactured by KEYENCE, trade name “Digital Microscope”, 200 times). The amount of resin entering is confirmed and memorized the position of the end of the SAW chip with an electron microscope from the glass substrate side before sealing with the hollow sealing sheet, and observed again with the electron microscope from the glass substrate side after sealing, The observation images before and after sealing were compared, and the maximum reach distance of the resin that entered the hollow portion from the end of the SAW chip that had been confirmed before sealing was measured, and this was taken as the amount of resin penetration. The case where the resin penetration amount was 20 μm or less was evaluated as “◯”, and the case where it exceeded 20 μm was evaluated as “×”. The results are shown in Table 1.

  As can be seen from Table 1, the hollow sealing sheets of Examples 1 to 5 had good flexibility. On the other hand, in Comparative Examples 1-2, cracks occurred and flexibility was inferior. Moreover, in Examples 1-5, compared with Comparative Examples 1-2, the resin approach amount to the slit of a metal mold | die was suppressed. Furthermore, in the SAW chip packages of Examples 1 to 5, it is found that the resin component of the hollow sealing sheet is prevented from entering the hollow portion, and a high-quality hollow package can be produced. In Comparative Examples 1 and 2, the amount of resin entering the hollow portion exceeded 20 μm.

DESCRIPTION OF SYMBOLS 11 Hollow sealing sheet 11a Support body 13 SAW chip 14 Hollow part 15 Sealing body 18 Hollow package 100 Molding die 110 Lower die 111 Groove 120 Upper die 130 Rod 200 Resin
L resin penetration
O inlet
S slit

Claims (5)

A hollow sealing sheet for hollow sealing electronic components,
Including resin,
A hollow sealing sheet in which resin penetration into a hollow portion is controlled at 40 ° C. or higher and 100 ° C. or lower. The resin penetration amount into the slit when filling the molding die having a slit with a width of 20 μm and pressurizing the resin for 10 minutes at a pressure of 10 kg / cm ² and a temperature of 150 ° C. is 3 mm or less. The hollow sealing sheet according to 1.   The hollow sealing sheet according to claim 2, wherein when plotting a resin ingress amount with respect to a slit having a width of 1 μm or more and 100 μm or less with respect to the slit width, a minimum value exists in the plot.   The hollow sealing sheet according to claim 3, wherein the minimum value is 2 mm or less. A lamination step of laminating the hollow sealing sheet according to any one of claims 1 to 4 while maintaining a hollow portion on the electronic component so as to cover one or a plurality of electronic components, and the hollow sealing sheet The manufacturing method of the hollow package including the sealing body formation process which hardens | cures and forms a sealing body.