TWI625798B - Hollow closed sheet and method of manufacturing hollow package - Google Patents

Abstract

The present invention provides a hollow sealing sheet and a method of manufacturing a hollow package which can produce a highly reliable hollow package. The present invention relates to a hollow closed sheet of a hollow closed electronic component which contains a resin and controls the ingress of the resin into the hollow portion at 40 ° C or more and 100 ° C or less. The resin was filled in a molding die having a slit having a width of 20 μm, and when the resin was pressed at a pressure of 10 kg/cm ² and a temperature of 150 ° C for 10 minutes, the amount of resin entering the slit was preferably 3 mm or less.

Description

Hollow closed sheet and method for manufacturing hollow package

The present invention relates to a method of manufacturing a hollow closed sheet and a hollow package.

In the production of an electronic component package such as a semiconductor, one or a plurality of electronic components fixed to a substrate or a temporary fixing material are sealed by a sealing resin, and the closure is cut as an electronic component unit package as needed. The order. As the sealing resin, a flaky sealing resin having good handleability is used. Further, as a technique for increasing the blending amount of the filler to improve the performance of the hollow sealing sheet, a technique of blending a filler into a sheet for sealing has been proposed (Patent Document 1).

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2013-7028

In recent years, in parallel with semiconductor packages, SAW (Surface Acoustic Wave) filters, or CMOS (Complementary Metal Oxide Semiconductor) sensors, acceleration sensors, etc. have been developed. Development of microelectronic parts for MEMS. Each of these electronic parts has a hollow structure for ensuring the propagation of a general surface elastic wave, the maintenance of an optical system, and the mobility of a movable member. When closing, it is necessary to ensure the movement of the movable member. The reliability or the connection reliability of the components is closed while maintaining the hollow structure. For the closed sheet, a requirement corresponding to the hollow package having the hollow structure is required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hollow sealing sheet and a method of manufacturing a hollow package which can produce a highly reliable hollow package.

As a result of a positive review by the inventors of the present invention, it has been found that the above problems can be solved by adopting the following configuration, and thus the present invention has been completed.

That is, the present invention is a hollow sealing sheet for a hollow enclosed electronic component which contains a resin and controls the ingress of the resin into the hollow portion at 40 ° C or more and 100 ° C or less.

Since the hollow closed sheet controls the entry of the resin into the hollow portion at 40 ° C or more and 100 ° C or less, the entry of the resin into the hollow portion can be suppressed at the time of hollow sealing, and a highly reliable hollow package can be produced.

The hollow sealing sheet is preferably filled with the resin in a molding die having a slit having a width of 20 μm, and the resin enters the slit at a pressure of 10 kg/cm ² and a temperature of 150 ° C for 10 minutes. the following. Thereby, since the ingress property of the resin to a specific slit under heat and pressure is suppressed, a hollow package having higher reliability can be produced. Further, the measurement of the amount of resin entering is as described in the examples.

The hollow closed sheet preferably has a minimum value in the drawing when the amount of penetration of the resin into 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 this minimum value is not certain, but is presumed as follows. For example, when the hollow sealing sheet contains fine particles imparted by dilatancy such as an inorganic filler or an elastomer particle, the expansion of the slit is performed in the peripheral region of the slit, and the entry of the resin into the slit is suppressed. When the slit width is sufficiently larger than the particle diameter of the fine particles, the effect of expansion is weak, and the resin easily enters the slit together with the fine particles, so that the resin entering amount becomes large. As the slit width becomes smaller, the effect of expansion becomes stronger, the amount of resin entering becomes smaller, and the amount of resin entering at a certain point becomes a minimum value. Therefore, when the slit width is equal to or less than a certain value, the entry of the secondary fine particles into the slit is restricted, and only the resin component enters the slit. When the resin is only expanded, the effect becomes weak, so the amount of resin entering becomes large. When the force applied to the hollow closed sheet is constant, the smaller the slit width, the resin is extruded toward the slit, and as a result, the amount of resin entering becomes larger. Accordingly, it is considered that the amount of resin entering has a minimum value for the plot of the slit width. Further, by utilizing this phenomenon, it is possible to design the composition of the hollow closed sheet in such a manner that the gap-like action is maximized with respect to the gap interval of the hollow portion, and it is possible to more effectively limit the entry of the resin into the hollow portion to produce high reliability. Hollow package.

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

The present invention relates to a method of manufacturing a hollow package, comprising the steps of: laminating a hollow sealing sheet on a side of the electronic component by laminating one or a plurality of electronic components, and maintaining the hollow portion An enclosure forming step of sealing the sheet to form an enclosure.

In the production method of the present invention, since the hollow closed sheet in which the entry property of the hollow portion is controlled by the resin is used, it is possible to manufacture a hollow package in which the hollow portion is favorably secured and the overall reliability is high.

11‧‧‧ hollow sealing sheets

11a‧‧‧Support

12‧‧‧Printed wiring substrate

13‧‧‧SAW chip

13a‧‧‧protruding electrode

14‧‧‧ Hollow

15‧‧‧Closed

18‧‧‧ hollow package

100‧‧‧Forming mould

110‧‧‧Next mold

111‧‧‧ditch

120‧‧‧Upper mold

130‧‧‧ great

200‧‧‧Resin

L‧‧‧resistance

O‧‧‧ input

S‧‧ slit

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view schematically showing a hollow sealing sheet according to an embodiment of the present invention.

Fig. 2A is a cross-sectional view schematically showing a step of a method of manufacturing a hollow package according to an embodiment of the present invention.

Fig. 2B is a cross-sectional view schematically showing a step of a method of manufacturing a hollow package according to an embodiment of the present invention.

Fig. 2C is a cross-sectional view schematically showing a step of a method of manufacturing a hollow package according to an embodiment of the present invention.

Figure 3 is a SEM of the cut surface of the hollow closed sheet of the embodiment of the present invention Observe the image.

Fig. 4A is a schematic cross-sectional view of a molding die for measuring the amount of entry of a resin into a slit of a molding die.

Figure 4B is a plan view of the lower mold of the forming mold.

Fig. 4C is a cross-sectional view showing a measurement procedure for measuring the amount of entry of the resin into the slit of the molding die.

"First Embodiment" [Hollow closed sheet]

The hollow sealing sheet of the present embodiment will be described with reference to Fig. 1 . BRIEF DESCRIPTION OF THE DRAWINGS 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 of a polyethylene terephthalate (PET) film or the like. Moreover, in order to facilitate the peeling of the hollow sealing sheet 11, the support body 11a may be subjected to a mold release treatment.

The entry of the resin of the hollow sealing sheet 11 at 40 ° C or more and 100 ° C or less with respect to the hollow portion 14 (refer to FIG. 2A) is controlled. According to this, the hollow package 18 (see FIG. 2C) obtained by using the hollow sealing sheet 11 can secure the hollow portion 14, and can achieve high reliability of the operation reliability and connection reliability of the electronic component.

The resin forming the hollow sealing sheet 11 is filled in a molding die having a slit having a width of 20 μm, and the resin enters the slit at a pressure of 10 kg/cm ² and a temperature of 150 ° C for 10 minutes. 3mm or less, more preferably 2mm or less. By setting the resin intrusion under heat and pressure to the above range, a hollow package having higher reliability can be produced.

The hollow closed sheet 11 preferably has a minimum value when the amount of penetration of the resin into the slit having a width of 1 μm or more and 100 μm or less is plotted against the slit width. According to this, it is possible to design a hollow sealing sheet for minimizing the amount of entry of the resin into the hollow portion, and it is possible to manufacture a hollow package having higher reliability.

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

The linear expansion ratio at 20 ° C after the hollow sealing sheet is thermally cured at 150 ° C for 1 hour is preferably 15 ppm / K or less, more preferably 10 ppm / K or less. According to this, warpage in the hollow package can be satisfactorily suppressed. The method of measuring the coefficient of linear expansion is as follows. The hollow closed sheet before hardening having a width of 4.9 mm, a length of 25 mm, and a thickness of 0.2 mm was cured at 150 ° C for 1 hour. The cured resin sheet was fixed to TMA8310 (manufactured by RIGAKU Co., Ltd.), and the linear expansion ratio was measured at a tensile load of 4.9 mN and a temperature increase rate of 10 ° C/min.

The resin composition forming the hollow closed sheet can be preferably imparted with the above-described characteristics, and is not particularly limited as long as it is a resin sealer which can be used for an electronic component such as a semiconductor wafer. Among them, it is preferable to contain a limiting material which can restrict the flow of the resin in the vicinity of the hollow portion. The limiting material can be used well A high-viscosity substance such as an elastomer or a high-viscosity epoxy resin or a high-viscosity phenol resin, or an inorganic filler or the like to expand the imparting fine particles.

The viscosity of the high-viscosity substance may be appropriately set in consideration of the degree of restriction of the flow of the resin or the workability, but it is preferably 2,000 Pa·s or more and 30,000 Pa·s or less at 80 ° C, more preferably 5,000 Pa·s or more and 25,000 or less. . Further, the viscosity can be measured by a parallel plate method using a viscoelasticity measuring apparatus ARES manufactured by TA Instruments. More specifically, the viscosity in the range of 50 ° C to 200 ° C was measured under the conditions of a gap of 100 μm, a rotating plate diameter of 20 mm, and a number of revolutions of 10 s ^-1 , and the viscosity at 80 ° C obtained at this time was read.

Preferred examples are epoxy resin compositions containing the following components A to E as specific components.

Component A: Epoxy

B component: phenolic resin

Component C: Elastomer

D component: inorganic filler

Component E: Hardening accelerator

(component A)

The epoxy resin (component A) which is a thermosetting resin is not particularly limited. For example, a triphenylmethane type epoxy resin, a cresol novolak type epoxy resin, a biphenyl type epoxy resin, a modified bisphenol A type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type can be used. Epoxy resin, modified bisphenol F type epoxy resin, dicyclopentadiene type epoxy resin, phenol novolac type epoxy tree Various epoxy resins such as grease and phenoxy resin. These epoxy resins may be used alone or in combination of two or more.

From the viewpoint of ensuring the toughness of the epoxy resin after hardening and the reactivity of the epoxy resin, it is preferable to use an epoxy equivalent of 150 to 250, a softening point or a melting point of 50 to 130 ° C at room temperature as a solid state, wherein From the viewpoint of reliability, a triphenylmethane type epoxy resin, a cresol novolak type epoxy resin, and a biphenyl type epoxy resin are preferable.

Further, from the viewpoint of low stress, a modified bisphenol A type epoxy resin having a soft skeleton such as an acetal group or a polyoxyalkylene group is preferred, and an acetal-based modified bisphenol is preferred. A type epoxy resin is particularly suitable because it is liquid and is handled well.

When the weight average molecular weight of the epoxy resin becomes large, the viscosity also becomes high, and the epoxy resin itself can function as the above-mentioned limiting material. The weight average molecular weight is not particularly limited as long as it can function as the above-mentioned limiting material, but is preferably 150 or more, more preferably 300 or more.

The content of the epoxy resin (component A) is preferably in the range of 1 to 10% by weight based on the total amount of the 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 a hardening reaction with an 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 resorcin resin, or the like can be used. These phenol resins may be used singly or in combination of two on.

As the phenol resin, from the viewpoint of reactivity with the epoxy resin (component A), it is preferred to use a hydroxyl group equivalent of 70 to 250 and a softening point of 50 to 110 ° C, wherein the curing reactivity is high. The phenol novolak resin can be preferably used. Further, from the viewpoint of reliability, a low hygroscopic property such as a phenol novolak resin or a biphenyl aralkyl resin can be preferably used.

The ratio of the epoxy resin (component A) to the phenol resin (component B) is preferably such that the total of the hydroxyl groups in the phenol resin (component B) is relative to the epoxy resin (component A) from the viewpoint of curing reactivity. In the case where the epoxy group 1 equivalent is 0.7 to 1.5 equivalents, it is preferably 0.9 to 1.2 equivalents.

When the weight average molecular weight of the phenol resin becomes large, the viscosity also becomes high, and the phenol resin itself can function as the above-mentioned limiting material. The weight average molecular weight is not particularly limited as long as it can function as the above-mentioned limiting material, but is preferably 150 or more, more preferably 300 or more.

Further, in the present specification, the method for measuring the weight average molecular weight can be measured by the following method. The sample was dissolved in THF at 0.1% by weight, and the weight average molecular weight was measured in terms of polystyrene using GPC (gel permeation chromatography). The detailed measurement conditions are as follows.

<Measurement conditions of weight average molecular weight>

GPC device: TOSOH system, HLC-8120GPC

Pipe column: TOSOH manufacturing (GMHHR-H) + (GMHHR-H) + (G2000HHR)

Flow rate: 0.8mL/min

Concentration: 0.1wt%

Injection volume: 100μL

Column temperature: 40 ° C

Dissolution: THF

(C component)

For the elastomer (component C) to be used together with the epoxy resin (component A) and the phenol resin (component B), for example, various acrylic copolymers or rubber components can be used. The rubber component is preferably contained from the viewpoint of improving the dispersibility of the epoxy resin (component A) or improving the heat resistance, flexibility, and strength of the obtained hollow closed sheet. The rubber component is preferably at least one selected from the group consisting of butadiene rubber, styrene rubber, acrylic rubber, and polyoxyn rubber. These may be used alone or in combination of two or more. The entry of the resin into the hollow portion can be better restricted by the elastomer containing the high viscosity substance.

Preferably, the block of the elastomer is dispersed in the hollow closed sheet, and the maximum diameter of the block is 20 μm or less. Thereby, the elastic body functions as a fine particle having a function of restricting the flow of the resin in the vicinity of the hollow portion (a function of expansion), and more effectively inhibits entry of the resin into the hollow portion. The elastomer may be partially aggregated or agglomerated, but in terms of the effect of expansion, it is preferable that the entire body is dispersed in the same manner. The upper limit of the maximum diameter of the block is not particularly limited as long as it is 20 μm or less, but preferably 15 μm or less, more preferably It is 10 μm or less. Further, the lower limit of the maximum diameter of the block is preferably 0.1 μm or more, and more preferably 0.3 μm or more from the viewpoint of the physical limit of the refinement and the flexibility.

The content of the elastomer (component C) is preferably from 1.0 to 3.5% by weight, more preferably from 1.5 to 3% by weight, based on the total amount of the epoxy resin composition. When the content of the elastomer (component C) is less than 1.0% by weight, it is difficult to obtain the flexibility and flexibility of the hollow sealing sheet 11, and it is difficult to prevent the resin from being warped by blocking the hollow sealing sheet. On the other hand, when the content is more than 3.5% by weight, the melt viscosity of the hollow sealing sheet 11 is increased, the embedding property of the electronic component is lowered, and the strength and heat resistance of the hardened body of the hollow sealing sheet 11 tend to be lowered.

Further, the weight ratio of the elastomer (component C) to the epoxy resin (component A) (weight of the component C/weight of the component A) is preferably set in the range of 0.5 to 1.5. The reason is that when the weight ratio is less than 0.5, it is difficult to control the fluidity of the hollow sealing sheet 11, and when it exceeds 1.5, the adhesion of the hollow sealing sheet 11 to the electronic component tends to be deteriorated.

The ratio Ee/Et of the tensile modulus Ee of the elastomer to the tensile modulus E of the thermosetting resin at 60 ° C is preferably 5 × 10 ^-5 or more and 1 × 10 ^-2 or less. It is preferably 1 × 10 ^-4 or more and 5 × 10 ^-3 or less. According to this, in the kneading process in the manufacturing process of the hollow closed sheet, the shear stress from the kneading member and the thermosetting resin acts effectively on the elastic body, and the miniaturization of the elastic body can be promoted. Moreover, the method of measuring the tensile elastic modulus Ee and Et can be carried out in the following order. Each of the elastic sheet and the thermosetting resin sheet was cut into a strip having a thickness of 200 μm, a length of 400 μm, and a width of 10 mm by a cutter to prepare a sample for measurement. The tensile modulus and the loss elastic modulus of the measurement sample at -50 to 300 ° C were measured using a solid viscoelasticity measuring apparatus (RSAIII, manufactured by Rheometric Scientific Co., Ltd.) at a frequency of 1 Hz and a temperature elevation rate of 10 ° C/min. The value of the tensile modulus at 60 ° C in the measurement was read to obtain the desired tensile modulus Ee and Et.

(D component)

The inorganic filler (component D) is not particularly limited, and various conventional fillers can be used, and examples thereof include quartz glass, talc, cerium oxide (melted cerium oxide or crystalline cerium oxide), alumina, and nitrogen. Powder of aluminum, tantalum nitride and boron nitride. These may be used alone or in combination of two or more. By containing an inorganic filler, it is possible to more effectively impart a function of expanding the hollow closed sheet in the vicinity of the hollow portion.

Among them, the internal stress is lowered by reducing the coefficient of thermal linear expansion of the hardened body of the epoxy resin composition, and as a result, it is preferable to use the cerium oxide from the viewpoint of suppressing the warpage of the hollow closed sheet 11 after the electronic component is closed. It is more preferable to use a molten cerium oxide powder in a powder or a cerium oxide powder. The molten cerium oxide powder is exemplified by spherical molten cerium oxide powder and crushed molten cerium oxide powder. However, from the viewpoint of fluidity, it is preferable to use spherical molten cerium oxide powder. Among them, those having an average particle diameter of 54 μm or less are preferably used, and those having a range of 0.1 to 30 μm are preferably used, and those having a range of 0.5 to 20 μm are preferably used.

Further, the average particle diameter can be measured by using a sample drawn from the parent group by using a laser diffraction scattering type particle size distribution measuring device. Out.

The content of the inorganic filler (component D) is preferably 70 to 90% by volume based on the entire epoxy resin composition (in the case of cerium oxide particles, the specific gravity is 2.2 g/cm ³ , so it is 81 to 94% by weight), It is preferably 74 to 85% by volume (84 to 91% by weight in the case of cerium oxide particles), and more preferably 76 to 83% by volume (85 to 90% by weight in the case of cerium oxide particles). When the content of the inorganic filler (component D) is less than 70% by volume, the linear expansion coefficient of the cured body of the epoxy resin composition becomes large, so that the warpage of the hollow closed sheet 11 tends to be large. On the other hand, when the content is more than 90% by weight, the flexibility or fluidity of the hollow sealing sheet 11 is deteriorated, so that the adhesion to the electronic component tends to decrease.

(E component)

The curing accelerator (component E) is not particularly limited as long as it can cure the epoxy resin and the phenol resin, but triphenylphosphine or tetraphenylphosphonium is preferably used from the viewpoint of hardenability and preservability. An organophosphorus compound such as a phenylborate or an imidazole compound. These hardening accelerators may be used singly or in combination with other hardening accelerators.

The content of the curing accelerator (component E) is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the total of the epoxy resin (component A) and the phenol resin (component B).

(other ingredients)

Moreover, in the epoxy resin composition, except for the components A to E In addition, a flame retardant component can also be added. As the flame retardant component, various metal hydroxides such as aluminum hydroxide, magnesium hydroxide, iron hydroxide, calcium hydroxide, tin hydroxide, and a composite metal hydroxide can be used.

The average particle diameter of the metal hydroxide is preferably from 1 to 10 μm, more preferably from 2 to 5 μm, from the viewpoint of ensuring proper fluidity when the epoxy resin composition is heated. When the average particle diameter of the metal hydroxide is less than 1 μm, it is difficult to uniformly disperse in the epoxy resin composition, and there is a tendency that sufficient fluidity cannot be obtained when the epoxy resin composition is heated. In addition, when the average particle diameter exceeds 10 μm, the surface area per amount of the metal hydroxide (component E) is small, so that the flame retarding effect tends to decrease.

Further, as the flame retardant component, in addition to the above metal hydroxide, a phosphazene compound may be used. The phosphazene compound can be obtained, for example, as a commercial product such as SPR-100, SA-100, SP-100 (above, Otsuka Chemical Co., Ltd.), FP-100, and FP-110 (above, Fushimi Pharmaceutical Co., Ltd.).

From the viewpoint of exerting a flame retardant effect in a small amount, it is preferably a phosphazene compound represented by the formula (1) or the formula (2), and the content of the phosphorus element contained in the phosphazene compound is preferably 12% by weight. %the above.

(In the formula (1), n is an integer of from 3 to 25, and R ¹ and R ² are the same or different and each has a group selected from the group consisting of an alkoxy group, a phenoxy group, an amine group, a hydroxyl group, and an allyl group. a monovalent organic group of a functional group).

(In the formula (2), n and m are each independently an integer of from 3 to 25, and R ³ and R ⁵ are the same or different and are selected from the group consisting of an alkoxy group, a phenoxy group, an amine group, a hydroxyl group and an allyl group. The monovalent organic group of the functional group of the composition, and R ⁴ is a divalent organic group having a functional group selected from the group consisting of an alkoxy group, a phenoxy group, an amine group, a hydroxyl group, and an allyl group).

Further, from the viewpoint of stability and suppression of pore formation, a cyclic phosphazene oligomer represented by the formula (3) is preferably used.

(In the formula (3), n is an integer of from 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).

The cyclic phosphazene oligomer represented by the above formula (3) can be obtained as a commercial product such as FP-100 or FP-110 (above, Fushimi Pharmaceutical Co., Ltd.).

The content of the phosphazene compound is preferably an epoxy resin (component A) contained in the epoxy resin composition, a phenol resin (component B), an elastomer (component D), a hardening accelerator (component E), and a phosphazene. 10 to 30% by weight of the total organic component of the compound (other components). In other words, when the content of the phosphazene compound is less than 10% by weight of the entire organic component, the flame retardancy of the hollow sealing sheet 11 is lowered, and the followability of the adherend (for example, a substrate on which an electronic component is mounted) is lowered. See the tendency to occur in the pores. When the content exceeds 30% by weight of the entire organic component, the surface of the hollow sealing sheet 11 is likely to be sticky, and the workability such as difficulty in alignment of the adherend tends to be lowered.

And using the above metal hydroxide and phosphazene compound, It is also possible to obtain a hollow sealing sheet 11 which is required to ensure the flexibility required for the sheet to be closed and which is excellent in flame retardancy. By using both, it is possible to obtain sufficient flame retardancy when only a metal hydroxide is used and sufficient flexibility when only a phosphazene compound is used.

Among the above-mentioned flame retardants, the deformability of the hollow closed sheet at the time of resin sealing molding, the followability to the irregularities of the electronic component or the adherend, and the adhesion to the electronic component or the adherend are preferably used. For organic flame retardants, it is especially preferred to use a phosphazene flame retardant.

Further, in addition to the above respective components, the epoxy resin composition may be appropriately blended with other additives such as pigments represented by carbon black.

(Manufacturing method of hollow closed sheet)

The method of producing the hollow closed sheet will be described below. The method for producing a hollow sealing sheet according to the present embodiment includes a kneading step of preparing a kneaded material containing an elastomer, and a molding step of forming the kneaded material into a thin shape to obtain a hollow sealing sheet.

(mixing step)

First, an epoxy resin composition is prepared by mixing the above components. The mixing method is not particularly limited as long as it can uniformly disperse and mix the components. Subsequently, the kneaded material is prepared by kneading each of the blending components containing the elastomer by a direct kneader or the like. At this time, the elastic system of the hollow closed sheet is dispersed in a block shape, and it is preferable to knead the large diameter of the block to be 20 μm or less.

Specifically, each component of the above A to E component and other additives as needed is mixed by a conventional method such as a kneading machine, and then the kneaded material is prepared by melt kneading. The method of melt-kneading is not particularly limited, and examples thereof include a method of performing melt-kneading by a conventional kneading machine such as a kneading roll, a pressure kneader, or an extruder. As for the kneading machine, for example, a kneading spiral having a spiral blade whose projection amount is smaller than that of other portions of the spiral blade from the screw shaft, or a shaft is provided, for example, in one of the axial directions One of the directions is a spiral kneading machine without a spiral blade. The portion where the protruding amount of the spiral blade is small or the portion without the spiral blade becomes a low shearing force and is low agitation, thereby eliminating air which is mixed by the high compression ratio of the kneaded material, and suppressing generation of pores in the obtained kneaded material.

The kneading condition is not particularly limited as long as the temperature is equal to or higher than the softening point of each of the above components, and is, for example, 30 to 150 ° C. When considering the thermosetting property of the epoxy resin, it is preferably 40 to 140 ° C, more preferably 60 to 120 ° C. The time is, for example, 1 to 30 minutes, preferably 5 to 15 minutes. Thereby, the kneaded material can be modulated.

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

(forming step)

The obtained kneaded product is formed into a sheet shape by extrusion molding, whereby a hollow closed sheet 11 can be obtained. Specifically, the hollow closed sheet 11 can be formed by directly extruding the kneaded material after the melt-kneading and cooling at a high temperature. The extrusion method is not particularly limited, and examples thereof include a T-die extrusion method, a roll calendering method, a roll kneading method, a co-extrusion method, and a calender molding method. The extrusion temperature is not particularly limited as long as it is at least the softening point of each of the above components. When considering the thermosetting property and moldability of the epoxy resin, it is, for example, 40 to 150 ° C, preferably 50 to 140 ° C, more preferably 70. ~120 °C. With the above, the hollow sealing sheet 11 can be formed.

The thickness of the hollow closed sheet 11 is not particularly limited, but is preferably from 100 to 2000 μm. When it is within the above range, the electronic component can be well sealed. Further, when the resin sheet is thin, the amount of heat generation can be reduced, and hardening and shrinkage are less likely to occur. As a result, the amount of package warpage can be reduced, and a highly reliable hollow package can be obtained.

The hollow closed sheets thus obtained may also be laminated and used in such a manner as to have a desired thickness. That is, the hollow sealing sheet may be used in a single layer structure, or may be laminated in a laminate of two or more layers.

[Manufacturing method of hollow package]

Next, a method of manufacturing the hollow package of the present embodiment using the above-described hollow sealing sheet will be described with reference to FIGS. 2A to 2C. 2A to 2C are cross-sectional views each schematically showing a step of a method of manufacturing a hollow package according to an embodiment of the present invention. This embodiment is a hollow closed thin The sheet is hollow-sealed to the electronic component mounted on the substrate to form a hollow package. Further, in the present embodiment, a SAW filter is used as the electronic component, and a printed wiring board is used as the adherend, but other elements may be used. For example, an element having a movable portion and requiring a hollow portion such as a capacitor or a sensing device, a light-emitting element, an oscillating element, or the like can be used as an electronic component, and a lead frame, a tape carrier, or the like can be used as the adherend. With either element, a high degree of protection can be achieved by resin encapsulation of electronic parts.

(Preparation step of a substrate on which a SAW wafer is mounted)

In the preparation step of the substrate on which the SAW wafer is mounted, the printed wiring board 12 on which the plurality of SAW wafers 13 are mounted is prepared (see FIG. 2A). The SAW wafer 13 can be formed by dicing a piezoelectric crystal formed with a specific comb-shaped electrode by a conventional method. A conventional device such as a flip chip bonding machine or a die bonder can be used for mounting the SAW wafer 13 on the printed wiring board 12. The SAW wafer 13 and the printed wiring board 12 are electrically connected to each other through the bump electrodes 13a such as bumps. Further, the hollow portion 14 is maintained between the SAW wafer 13 and the printed wiring board 12 so as not to interfere with the propagation of the surface elastic wave on the surface of the SAW wafer. The distance between the SAW wafer 13 and the printed wiring board 12 is determined according to the specifications of each element, and is generally about 15 to 50 μm.

(closed step)

The sealing step is to cover the hollow cover by covering the SAW wafer 13 The sheet 11 is laminated on the printed wiring substrate 12, and the SAW wafer 13 is sealed with the above-mentioned hollow sealing sheet resin (refer to FIG. 2B). The hollow sealing sheet 11 functions as a sealing resin for protecting the SAW wafer 13 and its additional elements from the external environment.

In the present embodiment, by using the hollow sealing sheet 11, the SAW wafer 13 can be embedded by attaching the SAW wafer 13 to the printed wiring board 12, and the production efficiency of the hollow package can be improved. In this case, the hollow sealing sheet 11 can be laminated on the printed wiring board 12 by a conventional method such as a hot press or a laminator. The hot pressurization condition is, for example, 40 to 120 ° C, preferably 50 to 90 ° C, and 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. . Further, when the adhesion and followability of the hollow sealing sheet 11 to the SAW wafer 13 and the printed wiring board 12 are improved, it is preferable to pressurize under reduced pressure conditions (for example, 0.1 to 5 kPa).

Since the micro-block of the elastic body is dispersed in the hollow sealing sheet 11, the entry of the resin component into the hollow portion 14 is suppressed, and the operation reliability or the connection reliability of the SAW wafer 13 can be improved.

(closed body forming step)

The closed body forming step thermally hardens the hollow closed sheet to form the closed body 15 (see FIG. 2B). The heat-hardening treatment condition of the hollow closed sheet is preferably from 100 ° C to 200 ° C, more preferably from 120 ° C to 180 ° C, as the heating time is preferably from 10 minutes to 180 minutes, more preferably from 30 minutes to 120 minutes. It can also be pressurized as needed. When pressurized, It is preferably used from 0.1 MPa to 10 MPa, more preferably from 0.5 MPa to 5 MPa.

(cutting step)

Next, cutting of the closing body 15 made of elements such as the hollow sealing sheet 11, the printed wiring board 12, and the SAW wafer 13 can be performed (see FIG. 2C). Thereby, the hollow package 18 in units of the SAW wafer 13 can be obtained. The cutting is usually carried out by fixing the above-mentioned closure body 15 by a conventionally used cutting sheet.

(substrate mounting step)

If necessary, a substrate mounting step of forming a rewiring and a bump on the hollow package 18 obtained above and attaching it to another substrate (not shown) may be performed. The mounting of the hollow package 18 to the substrate may use a conventional device such as a flip chip bonding machine or a die bonding machine.

"Second Embodiment"

In the first embodiment, the kneaded material is kneaded by kneading each of the blending components, and the kneaded product is extrusion-molded into a sheet shape. On the other hand, in the present embodiment, a paint obtained by dissolving or dispersing each component in an organic solvent or the like is applied to form a sheet. Since the coating method can form a film in a state in which the elastomer is dissolved or dispersed in a solvent or the like, the block size of the elastomer can be made small.

The specific production sequence of the paint is to properly mix the above A~E components and other additives as needed according to the usual methods, and uniformly dissolve. The solution is prepared by dissolving or dispersing in an organic solvent. Subsequently, the hollow cover sheet 11 can be obtained by applying the above paint to a support such as polyester and drying it. Then, if necessary, a release sheet for protecting a polyester film or the like on the surface of the hollow sealing sheet may be attached. The release sheet was peeled off when it was closed.

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

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

Example

Hereinafter, preferred embodiments of the present invention are exemplarily described in detail. However, the materials, the blending amounts, and the like described in the examples are not particularly limited as long as they are not particularly limited. And, in parts, means parts by weight.

[Example 1] (production of hollow closed sheets)

The following components were blended in a kneading machine, and the number of kneading revolutions was set to 300 rpm, the kneading treatment amount was set to 5 kg/hr, and the kneading was performed at 110 ° C for 10 minutes, followed by extrusion from the T die. Making thickness 200μm Hollow closed sheet.

[Embodiment 2]

A hollow closed sheet was produced in the same manner as in Example 1 except that the kneading treatment amount was changed to 3.5 kg/hr.

[Example 3]

Except that the number of kneading revolutions was set to 500 rpm, the same as in the first embodiment. A hollow closed sheet was prepared.

[Example 4]

A hollow closed sheet was produced in the same manner as in Example 1 except that the number of kneading revolutions was set to 1000 rpm.

[Example 5]

The same components as in Example 1 were dissolved and dispersed in a 1:1 mixed solvent of methyl ethyl ketone and toluene in the same compounding amount to prepare a paint having a solid content of 40% by weight.

The paint was applied onto the PET film subjected to the release treatment so that the thickness of the coating film after drying the solvent was 50 μm, and then the drying conditions were set to 120 ° C for 3 minutes to dry the coating film to obtain a thickness of 50 μm. Resin sheet. The obtained resin sheet was laminated using a laminator to a thickness of 200 μm to prepare a hollow closed sheet having a thickness of 200 μm.

[Comparative Example 1]

A hollow closed sheet was produced in the same manner as in Example 1 except that the number of kneading revolutions was changed to 100 rpm.

[Comparative Example 2]

A hollow closed sheet was produced in the same manner as in Example 1 except that the number of kneading revolutions was changed to 50 rpm.

(Evaluation of flexibility of hollow closed sheets)

The sealing sheets of the examples and the comparative examples were cut into a width of 60 mm × a length of 60 mm, and the both end portions of the hollow sealing sheet (the side faces in the plan view) were slowly bent by 90°, and the flexibility was evaluated by the following criteria. The results are shown in Table 1.

○: bending at 90° without cracking

△: Crack occurs when bent at 90°

×: Crack when bent at 90°

(observation of blocks of elastomer)

After the produced hollow closed sheet was thermally hardened at 150 ° C and slowly cooled to room temperature, the obtained cured product was cut with a cutter. The cut surface was polished by an automatic polishing apparatus manufactured by Beauler, and the cut surface after the polishing was observed by SEM (2000 times). Fig. 3 shows an SEM observation image of the cut surface of the hollow closed sheet of Example 1. The area indicated by black in the image was observed by SEM as an elastomer block. Next, 50 points of the block of the elastomer shown in black were randomly selected, and the largest diameters of these were measured and averaged as the maximum diameter of the block. The same SEM observation and maximum diameter measurement were also carried out in the 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 entering amount of forming die with slit)

The amount of entry of the resin into the slit was measured using a slit forming mold shown in Figs. 4A to 4C. As shown in FIG. 4A, the forming die 100 has a profile of a rising portion of the outer peripheral portion of the disk. The lower mold 110 is formed with the upper mold 120, and a slit S and a hollow portion for accommodating the resin 200 are provided between the lower mold 110 and the upper mold 120. The input port O of the resin 200, which is a measurement sample, is provided at the center of the upper mold 120. As shown in Fig. 4B, a plurality of grooves 111 cut into a specific depth from above are provided on the upper portion of the rising portion of the mold 110 in a plan view. When the cut-in depth of each groove 111 is combined with the upper mold 120, the value of the width of the specific slit S is obtained.

The order of measurement of the actual resin entering amount is as follows. As shown in FIG. 4C, after the resin 200 is put into the mold from the inlet port O on the forming mold 100, the rod 130 for pressurization is inserted into the inlet port O, and the forming is performed. When the entire mold 100 is heated by the rod 130 while being heated, the evaluation is performed based on the extent to which the resin 200 enters the slit S. The distance L from the inner peripheral end portion of the slit S at this time to the maximum reaching point of the resin 200 was measured as the resin entry amount. The measurement conditions are as follows, and the results are shown in Table 1.

<Measurement conditions>

Heating temperature: 150 ° C

Pressure: 10kg/cm ²

Pressurization time: 10 minutes

Slit width: 1μm, 5μm, 10μm, 20μm, 50μm

(Resin evaluation of the entry of the hollow part of the package)

The SAW wafer of the following specifications in which the aluminum comb type electrode was formed was mounted on a glass substrate under the following bonding conditions to fabricate a SAW wafer mounting substrate.

<SAW wafer>

Wafer size: 1.4 × 1.1 mm □ (thickness 150 μm)

Bump material: Au height 30μm

Number of bumps: 6 bumps

Number of wafers: 100 (10 × 10)

<Adhesive condition>

Device: Panasonic Electrician (share) system

Bonding conditions: 200 ° C, 3 N, 1 second (ultrasonic output 2 W)

Each of the hollow closed sheets was vacuum-pressed and attached to the obtained SAW wafer mounting substrate under the heat and pressure conditions shown below.

<attach condition>

Temperature: 60 ° C

Pressure: 4MPa

Vacuum degree: 1.6kPa

Pressurization time: 1 minute

After opening to atmospheric pressure, the hollow closed sheet was thermally hardened in a hot air dryer at 150 ° C for 1 minute to obtain a closed body. The amount of penetration of the resin into the hollow portion between the SAW wafer and the glass substrate was measured from the glass substrate side by an electron microscope (manufactured by KEYENCE, "DIGITAL MICROSCOPE", 200 times). The amount of resin entering is determined by an electron microscope from the side of the glass substrate and the end position of the SAW wafer is confirmed by a hollow closed sheet before sealing. The electron microscope was observed from the side of the glass substrate, and the observation image before and after the closure was compared, and the maximum distance of arrival of the end portion of the SAW wafer confirmed from the resin before entering the hollow portion was measured, and this was taken as the resin entry amount. When the resin entering amount was 20 μm or less, the evaluation was "○", and when it was more than 20 μm, it was evaluated as "×". The results are shown in Table 1.

As is clear from Table 1, the hollow closed sheets of Examples 1 to 5 were excellent in flexibility. On the other hand, cracks occurred in Comparative Examples 1 and 2, and the flexibility was poor. Further, in Examples 1 to 5, compared with Comparative Examples 1 and 2, the amount of penetration of the resin into the slit of the mold was suppressed. Further, it can be seen that in the SAW wafer packages of Examples 1 to 5, the entry of the resin component of the hollow sealing sheet into the hollow portion is suppressed, and a high-quality hollow package can be produced. In Comparative Examples 1 and 2, the amount of entry of the resin into the hollow portion exceeded 20 μm.

Claims (5)

A hollow sealing sheet for hollow sealing sheets of hollow closed electronic parts, which contains a resin and controls the ingress of the resin into the hollow portion at 40 ° C or more and 100 ° C or less. The hollow sealing sheet of claim 1, wherein the resin is filled in a molding die having a slit having a width of 20 μm, and the resin is applied to the slit at a pressure of 10 kg/cm ² and a temperature of 150 ° C for 10 minutes. The amount of entry is 3mm or less. The hollow closed sheet of claim 2, wherein the amount of entry of the resin into the slit having a width of 1 μm or more and 100 μm or less is plotted against the slit width, and there is a minimum value in the drawing. The hollow closed sheet of claim 3, wherein the aforementioned minimum value is 2 mm or less. A method of manufacturing a hollow package, comprising the steps of: maintaining a hollow laminated sheet of any one of claims 1 to 4 on the electronic component by coating one or a plurality of electronic components And a step of forming a closed body forming the closed body by hardening the hollow closed sheet.