JP2016127182A - Method for fabricating multilayer sealing resin sheet, and multilayer sealing resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a method for fabricating a multilayer sealing resin sheet which enables the manufacturing of a highly reliable electronic component package with good solder resistant reflowability; and a multilayer sealing resin sheet.SOLUTION: A method for fabricating a multilayer sealing resin sheet comprises: a coating step for manufacturing unit resin sheets by a coating method; and a lamination step for manufacturing the multilayer sealing resin sheet by laminating the unit resin sheets. The lamination step is performed at a lamination plane temperature of 85°C or higher and under an atmosphere of a reduced pressure of 10 kPa or below.SELECTED DRAWING: Figure 1B

Description

  The present invention relates to a method for producing a multilayer sealing resin sheet and a multilayer sealing resin sheet.

  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 for improving the performance of the sealing sheet, a technique for blending the filler by kneading into the sealing sheet has been proposed (Patent Document 1).

JP 2013-7028 A

  However, since it is necessary to prepare a kneader separately in the kneading technique, the present inventors have made a technique for producing a sealing resin sheet easily and at low cost while utilizing a thin film forming technique by conventional coating. Is also under consideration.

  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. These electronic components generally have a hollow structure for ensuring the propagation of surface acoustic waves, the maintenance of 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.

  With the increasing complexity and size of elements mounted on such a substrate, a thick sealing resin sheet is required. In order to form the sealing resin sheet by a coating method, it is necessary to apply a raw material mixture containing a solvent into a sheet and remove the solvent during drying to make it a semi-cured state. In the case of a thick sheet, the vicinity of the surface may be dried first and the internal solvent may not be sufficiently diffused and remain. When the encapsulating resin sheet in which the solvent remains is used in the electronic component package manufacturing process, the encapsulating resin sheet may foam and cause quality deterioration. Such a tendency becomes more prominent when the content of the inorganic filler is high. Therefore, the coating method has a limit on the sheet thickness, and it is difficult to form a sealing resin sheet having a target thickness.

  Then, the present inventors are advancing examination about producing the sealing resin sheet which has the target thickness by laminating | stacking the thin sealing resin sheet formed by the coating method. However, it has been found that when sealing is performed with a laminated sealing resin sheet, the solder reflow resistance is lowered and the reliability is lowered.

  The objective of this invention is providing the manufacturing method of a multilayer sealing resin sheet which can produce the highly reliable electronic component package which has favorable solder reflow resistance, and a multilayer sealing resin sheet.

  As a result of investigations by the present inventors, voids are generated at the interface (hereinafter also referred to as “lamination interface”) where the upper and lower sealing resin sheets are in contact with each other when the sealing resin sheets are laminated. It came to the knowledge that solder reflow resistance has fallen by expanding. As a result of further studies, the inventors have found that the above-described problems can be solved by adopting the following configuration, and have completed the present invention.

That is, the present invention includes a coating process for producing a plurality of unit resin sheets by a coating method, and a laminating process for producing a multilayer encapsulating resin sheet by laminating the plurality of unit resin sheets,
It is related with the manufacturing method of the multilayer sealing resin sheet which performs the said lamination process in 85 degreeC or more of lamination surface temperature, and the pressure-reduced atmosphere of 10 kPa or less.

  In the production method, when the unit resin sheets formed by the coating method are laminated, the lamination surface temperature is set to 85 ° C. or higher and a reduced pressure atmosphere of 10 kPa or less, so that the adhesion between the unit resin sheets can be improved. As a result, voids at the lamination interface of the obtained multilayer sealing resin sheet can be efficiently reduced or suppressed. Thereby, the solder reflow resistance of the electronic component package produced using a multilayer sealing resin sheet can be improved.

  In the said manufacturing method, it is preferable to perform the said lamination process using a roll-type laminator. According to the roll type laminator, the upper and lower unit resin sheets are laminated while being fed between the rolls, so that the unit resin sheets can be bonded together so as to extrude voids from the lamination interface, thereby improving the adhesion between the unit resin sheets. This can enhance the solder reflow resistance of the multilayer encapsulating resin sheet.

  The pressure on the unit resin sheet in the laminating step is preferably 0.05 to 0.3 MPa. By setting the pressing at the time of lamination within the above range, it is possible to favorably extrude voids from the lamination interface, and to prevent generation of wrinkles in the multilayer sealing resin sheet after lamination.

  The unit resin sheet may include an inorganic filler, and the content of the inorganic filler in the unit resin sheet may be 70% by volume or more. When the content of the inorganic filler is high, the tackiness of the surface of the unit resin sheet tends to be reduced or the surface irregularities tend to be large, and voids are easily bitten during lamination. In the manufacturing method, since the lamination surface temperature and the degree of pressure reduction in the lamination process are respectively in a predetermined range, even in the unit resin sheets having a high content of the inorganic filler and easy to bite the void, the voids are satisfactorily suppressed. Can be laminated.

  The thickness of the multilayer encapsulating resin sheet is preferably 70 μm or more. According to the manufacturing method, the multilayer encapsulating resin sheet can be thickened to the extent that it was difficult as the thickness of the unit resin sheet formed by the coating method.

  The present invention also includes a multilayer sealing resin sheet in which the size of the laminated interface void obtained by the method for manufacturing the multilayer sealing resin sheet is 100 μm or less.

  Since the multilayer encapsulating resin sheet of the present invention is obtained through this manufacturing method, the size of the laminated interface void is suppressed to 100 μm or less, and can exhibit excellent solder reflow resistance, and highly reliable electronic A component package can be produced.

It is sectional drawing which shows typically the coating process which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the lamination process which concerns on one Embodiment of this invention. It is sectional drawing which shows typically 1 process of the manufacturing method of the electronic component package which concerns on one Embodiment of this invention. It is sectional drawing which shows typically 1 process of the manufacturing method of the electronic component package which concerns on one Embodiment of this invention. It is sectional drawing which shows typically 1 process of the manufacturing method of the electronic component package which concerns on one Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, parts unnecessary for explanation are omitted, and there are parts enlarged or reduced for easy explanation.

<< Method for producing multilayer encapsulating resin sheet >>
The manufacturing method of the multilayer encapsulating resin sheet of the present embodiment includes a coating process for producing a plurality of unit resin sheets by a coating method, and a laminating process for producing a multilayer encapsulating resin sheet by laminating the plurality of unit resin sheets. including.

(Coating process)
In this embodiment, a raw material mixture (so-called varnish) in which each component is dissolved or dispersed in an organic solvent or the like is applied to form a sheet-like unit resin sheet. FIG. 1A is a cross-sectional view schematically showing a coating process according to an embodiment of the present invention. In the coating method, since a sheet can be formed using a conventionally used thin film forming technique without using a dedicated device such as a kneader, a unit resin sheet can be formed easily and at low cost. .

  As a specific production procedure using a raw material mixture, first, each component (details will be described later) is appropriately mixed according to a conventional method, and uniformly dissolved or dispersed in an organic solvent to prepare a raw material mixture.

  The organic solvent is not particularly limited, and various conventionally known 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. Usually, it is preferable to use an organic solvent so that the solid content concentration of the raw material mixture is in the range of 30 to 95% by weight.

  Although it does not specifically limit as a viscosity at 90 degrees C of a raw material mixture, 10-1000 Pa.s is preferable from the point of film-forming uniformity and handling property, and 50-600 Pa.s is more preferable. The viscosity is measured by measuring the static viscosity by a parallel plate method using a raw material mixture as a sample and using a rotary viscometer (manufactured by Thermo Fisher Scientific, product name “HAAKE Roto Visco 1”). Specifically, the measurement is performed by raising the temperature from 50 ° C. to 90 ° C. under conditions of a gap of 1000 μm, a rotating plate diameter of 8 mm, a strain amount of 0.05%, a frequency of 1 Hz, and a heating rate of 30 ° C./min. The viscosity at 90 ° C. at that time is read to determine the viscosity [Pa · s] of the raw material mixture.

  Next, the unit resin sheet 1 can be obtained by applying the raw material mixture on a support 1a such as polyester and drying it. And if necessary, in order to protect the surface of the unit resin sheet 1, you may bond together peeling sheets, such as a polyester film. The release sheet is peeled off at the time of lamination or sealing.

  The coating method is not particularly limited, and a conventionally known coating method can be employed. Examples thereof include a comma coating method, a fountain method, and a gravure method.

  The thickness of the unit resin sheet 1 after drying the organic solvent is not particularly limited, but is preferably set to 10 to 70 μm, more preferably 20 to 60 μm, from the viewpoint of thickness uniformity and residual solvent amount. It is.

  The drying temperature of the coating film is not particularly limited as long as the solvent can be removed, and is typically set within a range of 60 to 160 ° C. Furthermore, it is preferable to raise the drying temperature stepwise as the drying time elapses. For example, it is set within the range of 70 to 100 ° C. for 1 minute immediately after the introduction of the dryer, and is set within the range of 100 to 160 ° C. for more than 1 minute and up to 3 minutes. Thereby, it can prevent suitably that only the surface vicinity dries and a solvent remains inside.

  The drying time is appropriately set according to the coating thickness of the raw material mixture, and is usually in the range of 1 to 5 minutes, preferably 2 to 3 minutes. If the drying time is too short, the amount of unreacted cured components and remaining solvent due to not reaching the semi-cured state (B-stage state) increases, which may cause foaming problems in the subsequent process. is there. On the other hand, if the drying time is too long, the curing reaction proceeds too much, and the fluidity and embeddability to the adherend may be reduced.

  The residual solvent amount in the unit resin sheet 1 after drying is preferably 500 ppm or less, and more preferably 300 ppm or less, from the viewpoint of suppressing foaming when the multilayer encapsulating resin sheet is used in the manufacturing process of the electronic component package.

  It does not specifically limit as the support body 1a, A conventionally well-known thing can be used. Specifically, for example, a substrate in which a release coating layer such as a silicone layer is formed on the surface of the base material of the support 1a to be bonded to the unit resin sheet 1 can be mentioned. Examples of the base material of the support 1a include paper materials such as glassine paper, and resin films made of polyethylene, polypropylene, polyester, and the like. In this embodiment, since the coating method is adopted, when the base material of the support 1a is long, the long unit resin sheet 1 is continuously formed on the support 1a while being transported. Can do.

  The thickness of the support 1a may be appropriately set in consideration of handling properties in a subsequent process, and is generally in the range of 25 to 200 μm, preferably in the range of 35 to 125 μm.

(Lamination process)
In the lamination step, a plurality of unit resin sheets formed in the coating step are laminated to produce a multilayer encapsulating resin sheet.

  The lamination step can be performed by a method using a roll laminator or a method using a press plate laminator. In this embodiment, as shown in FIG. 1B, it is preferable to perform a lamination process using a roll-type laminator. FIG. 1B is a cross-sectional view schematically showing a lamination process according to an embodiment of the present invention. According to the roll laminator, the upper and lower unit resin sheets 1 and 1 ′ are stacked while being fed between the rolls R and R, so that the unit resin sheets 1 and 1 ′ can be bonded to each other so as to extrude a void from the stacking interface. . Thereby, the adhesiveness between unit resin sheet 1, 1 'can be improved, and the solder reflow resistance of the obtained multilayer sealing resin sheet 11 can be improved more. Moreover, a lamination process can be performed continuously and the manufacturing efficiency of a multilayer sealing resin sheet can be improved.

  In this step, it is preferable that the temperature (lamination surface temperature) of the lamination surface (the surface of one unit resin sheet bonded to the other unit resin sheet) S of the unit resin sheet 1 is 85 ° C. or higher, 90 More preferably, the temperature is higher than or equal to ° C. By setting the lamination surface temperature within the above range, the surfaces of the unit resin sheets 1 and 1 'can be appropriately softened, and the adhesion between the unit resin sheets can be further enhanced. The upper limit of the lamination surface temperature can be set according to the heat resistant temperature of the support 1a to be used, and is usually 130 ° C or lower, preferably 120 ° C or lower, more preferably 110 ° C or lower. Specifically, when a polyethylene terephthalate film is used as the support 1a, the temperature is set in the range up to about 110 ° C, and in the polyethylene naphthalate film, the temperature is set in the range up to about 130 ° C.

  In FIG. 1B, only the lamination surface S of the upper unit resin sheet 1 is shown as the lamination surface of the unit resin sheet, but the temperature range is substantially the same even on the lamination surface of the lower unit resin sheet 1 ′. The temperature range is the same. The measurement location of the temperature of the laminated surface S is within a range of 10 mm or less in the distance along the surface in the rear in the MD direction (rear in the flow direction) from the point where the laminated surfaces of the upper and lower unit resin sheets 1 and 1 ′ start to contact each other Measure with The measurement is performed by bringing a thermocouple into contact with the laminated surface S.

  The heating method of the lamination surface S is not particularly limited, for example, using rolls that can be temperature controlled as rolls R, R, blowing hot air to the lamination surface S, performing the entire system of the lamination process in a heating furnace, These can be performed in combination.

  In this embodiment, it is preferable to perform a lamination process in the reduced pressure atmosphere of 10 kPa or less. The degree of reduced pressure is more preferably 8 kPa or less, and further preferably 5 kPa or less. In addition, although the pressure reduction degree is so preferable that it is low, it should just be 2 kPa or more from the point of manufacturing efficiency. By performing the laminating step under such a reduced pressure atmosphere, it is possible to reduce or suppress the entry of voids into the laminating interface, and to further improve the adhesion. Depressurization may be performed by discharging the gas in the system with an exhaust pump.

  In the laminating step, pressure may be applied to the unit resin sheet. The pressing is preferably 0.05 to 0.3 MPa, and more preferably 0.1 to 0.2 MPa. By setting the pressing at the time of lamination within the above range, it is possible to favorably extrude voids from the lamination interface, and to prevent generation of wrinkles in the multilayer sealing resin sheet after lamination. In the roll-type laminator shown in FIG. 1B, the pressure is measured as the pressure of the upper roll R on the unit resin sheet 1 (the pressure of the lower roll R on the unit resin sheet 1 ′ is also the same value).

  The laminating speed (conveying speed) may be set in consideration of the adhesion at the laminated interface between the unit resin sheets, the manufacturing efficiency, and the like. The laminating speed is preferably 0.5 to 3.0 m / min, more preferably 1.0 to 2.0 m / min.

  A multilayer encapsulating resin sheet can be obtained by repeating the above lamination process until the thickness of the multilayer encapsulating resin sheet is reached. For example, when a unit resin sheet has a thickness of 50 μm and a multilayer encapsulating resin sheet having a thickness of 200 μm is manufactured, first, a unit resin sheet having a thickness of 50 μm is laminated to form a 100 μm resin sheet. A multilayer encapsulating resin sheet having a thickness of 200 μm can be produced by laminating two obtained resin sheets having a thickness of 100 μm. Of course, a unit resin sheet having a thickness of 50 μm may be sequentially laminated so as to have a thickness of 100 μm, 150 μm, and 200 μm to produce a multilayer encapsulating resin sheet. It is also possible to laminate unit resin sheets having different thicknesses and compositions.

  Thereafter, if necessary, a process such as an inspection process for inspecting the presence or absence of voids at the laminated interface and a cutting process for cutting into a predetermined plan view size may be provided.

<Multilayer encapsulating resin sheet>
In the multilayer encapsulating resin sheet obtained by the above-described method for producing a multilayer encapsulating resin sheet, the size (maximum diameter in plan view) of voids (lamination interface voids) existing at the lamination interface is 100 μm or less. The size of the laminated interface void is preferably 50 μm or less, and more preferably 30 μm or less. Thus, since the size of the laminated interface void is reduced in the multilayer encapsulating resin sheet, foaming during solder reflow can be suppressed, and a highly reliable electronic component package can be manufactured.

Since the multilayer encapsulating resin sheet is a laminate of unit resin sheets, it has substantially the same composition as the unit resin sheet. Hereinafter, the composition of the multilayer encapsulating resin sheet will be described, but the same applies to the composition of the unit resin sheet. The resin composition forming the multilayer sealing resin sheet is not particularly limited as long as it can be used for resin sealing of electronic components such as semiconductor chips. From the viewpoint of improving heat resistance and stability after curing the multilayer encapsulating resin sheet, an epoxy resin composition containing the following components A to E as specific components is preferable.
A component: Epoxy resin B component: Phenol resin C component: Elastomer D component: Inorganic filler E component: Curing accelerator

(Component A)
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.

  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.

(C component)
The elastomer (C component) used together with the epoxy resin (A component) and the phenol resin (B component) is not particularly limited, and for example, various acrylic copolymers and rubber components can be used. From the viewpoint of dispersibility in the epoxy resin (component A) and the heat resistance, flexibility, and strength of the resulting multilayer encapsulating resin sheet, it is preferable to include a rubber component. 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.

  The content of the elastomer (component C) is preferably 1.0 to 3.5% by weight, more preferably 1.0 to 3.0% by weight, based on the entire epoxy resin composition. 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 multilayer encapsulating resin sheet 11, and further the resin that suppresses the warpage of the multilayer encapsulating resin sheet Sealing is also difficult. On the other hand, when the content exceeds 3.5% by weight, the melt viscosity of the multilayer encapsulating resin sheet 11 is increased, the embedding property of the electronic component is lowered, and the strength of the cured body of the multilayer encapsulating resin sheet 11 is reduced. In addition, the heat resistance tends to decrease.

(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.

  Among them, the internal stress is reduced by reducing the thermal expansion coefficient of the cured product of the epoxy resin composition, and as a result, the warpage of the multilayer encapsulating resin sheet 11 after sealing of the electronic component can be suppressed. It is preferable to use a powder, and it is more 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 these, those having an average particle size in the range of 54 μm or less are preferably used, those having a range of 0.1 to 30 μm are more preferable, and those having a 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 (component D) 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 multilayer encapsulating resin sheet 11 tends to increase. On the other hand, if the content exceeds 90% by volume, the surface unevenness caused by the inorganic filler becomes too large, or the flexibility and fluidity of the multilayer encapsulating resin sheet 11 deteriorates, so that the adhesiveness to the electronic component is deteriorated. There is a tendency to decrease.

  When the content of the inorganic filler in the multilayer encapsulating resin sheet 11 is as high as the above range, the tackiness of the unit resin sheet surface may be reduced or the unevenness may be increased, Voids are likely to occur. However, in the manufacturing method of this embodiment, since the lamination is performed at a predetermined lamination surface temperature and a reduced-pressure atmosphere, generation of voids at the lamination interface can be suppressed, and a multilayer encapsulating resin sheet with few interlayer voids can be obtained. Can be manufactured.

(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. 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. As the cyclic phosphazene oligomer, for example, FP-100, FP-110 (above, Fushimi Pharmaceutical Co., Ltd.) and the like are commercially available. From the viewpoint of exhibiting a flame retardant effect even in a small amount, the content of the phosphorus element contained in the phosphazene compound is preferably 12% by weight or more.

  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 Manufacturing Electronic Component Package >>
Next, the manufacturing method of the electronic component package which concerns on this embodiment using the said multilayer sealing resin sheet is demonstrated, referring FIG. 2A to 2C are cross-sectional views schematically showing one process of a method for manufacturing an electronic component package according to an embodiment of the present invention. In this embodiment, the electronic component mounted on the substrate is hollow-sealed with a multilayer sealing resin sheet to produce an electronic component 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, a capacitor, a sensor device, a light emitting element, a vibration 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 an adherend. Moreover, it is also possible to temporarily fix electronic components on a temporary fixing material without using an adherend, and to seal them with a resin. Even if any element is used, a high degree of protection by resin sealing of the electronic component can be achieved. Moreover, although hollow sealing is carried out, you may carry out solid sealing so that a hollow part may not be included using an underfill material etc. depending on sealing object.

(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 multilayer sealing resin 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 multilayer sealing resin sheet (see FIG. 2B). This multilayer encapsulating resin sheet 11 functions as an encapsulating resin for protecting the SAW chip 13 and its accompanying elements from the external environment.

  In the present embodiment, by adopting the multilayer sealing resin 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 electronic component package. Can be improved. In this case, the multilayer sealing resin 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 multilayer encapsulating resin sheet 11 to the SAW chip 13 and the printed wiring board 12, it is preferable that pressing is performed under reduced pressure conditions (for example, 0.1 to 5 kPa). preferable.

(Sealing body forming process)
In the sealing body forming step, the multilayer sealing resin sheet is thermoset to form the sealing body 15 (see FIG. 2B). The thermosetting treatment conditions of the multilayer encapsulating resin 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. In the meantime, 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 multilayer sealing resin sheet 11, the printed wiring board 12, and the SAW chip 13 may be performed (see FIG. 2C). Thereby, the electronic component 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 electronic component package 18 obtained above and mounted on a separate substrate (not shown). A known device such as a flip chip bonder or a die bonder can be used for mounting the electronic component package 18 on the substrate.

  In the following, 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 the examples 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>
The following components were dissolved or dispersed in a 1: 1 mixed solvent of methyl ethyl ketone and toluene to prepare a raw material mixture having a solid content of 40% by weight (inorganic filler content: 75% by weight).

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: (manufactured by Kaneka Corporation, SIBSTAR 102T) 4.0 parts Inorganic filler: spherical fused silica (Denki Kagaku Kogyo FB-9454FC) 87.0 parts Carbon black (Mitsubishi Chemical Corporation, # 20) 0.1 part Flame retardant: (FP-100, Fushimi Pharmaceutical Co., Ltd.) 8 parts Curing accelerator: Imidazole catalyst (manufactured by Shikoku Chemicals Co., Ltd., 2PHZ-PW) 0.1 part

  On the 100 μm thick PET film that has been subjected to the mold release treatment, the raw material mixture is applied by a fountain method so that the thickness of the coating film after solvent drying is 50 μm, and then the drying condition is 120 ° C. for 4 minutes. The coating film was dried to obtain a unit resin sheet having a thickness of 50 μm.

  The unit resin sheet obtained by coating was laminated to a thickness of 200 μm with a roll-type vacuum pressurizing laminator (manufactured by Hitachi AIC, product name “HLM-VF300ND”). In the first laminating process, two unit resin sheets were laminated to form a resin sheet having a thickness of 100 μm, and then two resin sheets having a thickness of 100 μm were laminated to form a multilayer encapsulating resin sheet having a thickness of 200 μm. The laminating conditions were as follows: both at the first time and at the second time, the degree of vacuum was 6 kPa (standard pressure was reduced from 101 kPa to 95 kPa), the laminating surface temperature was 90 ° C., the laminating speed was 1.0 m / min, the laminating roll temperature was 100 ° C., and the laminating roll pressure was 0.1 MPa. Met.

<Example 2>
A multilayer encapsulating resin sheet was produced in the same manner as in Example 1 except that the lamination surface temperature was 100 ° C. and the laminate roll temperature was 110 ° C. as the lamination conditions.

<Example 3>
A multilayer encapsulating resin sheet was produced in the same manner as in Example 1 except that the lamination roll pressure was 0.3 MPa as the lamination condition.

<Example 4>
A multilayer encapsulating resin sheet was produced in the same manner as in Example 1 except that the lamination roll pressure was 0.5 MPa as the lamination condition.

<Comparative Example 1>
A multilayer encapsulating resin sheet was produced in the same manner as in Example 1 except that the lamination surface temperature was 70 ° C. and the laminate roll temperature was 80 ° C. as the lamination conditions.

<Comparative example 2>
A multilayer encapsulating resin sheet was produced in the same manner as in Example 1 except that the depressurization degree was set to 16 kPa (decompression from the standard pressure of 101 kPa to 85 kPa) as the lamination condition.

(Evaluation)
The following items were evaluated with respect to the produced multilayer sealing resin sheet. The results are shown in Table 1.

(Presence of laminated interface voids)
The multilayer sealing resin sheet was cut with a cutter, and the cross-section was observed with an optical microscope (1000 times). Further, the exposed surface of the multilayer encapsulating resin sheet (the surface opposite to the PET film side) was irradiated with a high-intensity halogen lamp, and a transmitted light inspection was performed. In both the cross-sectional observation and the transmitted light inspection, the case where there is no void having a maximum diameter of 100 μm in plan view is “◯”, and the case where there is a void having a maximum diameter exceeding 100 μm in any one of the cases. Evaluated as “x”.

(Presence or absence of foaming after thermosetting)
After the multilayer encapsulating resin sheet was thermoset at 160 ° C. for 1 hour, the surface and the cross section were visually observed. The case where foaming was not confirmed was evaluated as “◯”, and the case where foaming was confirmed was evaluated as “x”.

(Wrinkle generation in the lamination process)
In the laminating process, the resin sheet having a thickness of 100 μm obtained in the first laminating process and the multilayer encapsulating resin sheet having a thickness of 200 μm obtained in the second laminating process were visually checked for wrinkles. And observed. The case where no wrinkles were confirmed was evaluated as “◯”, the case where slight wrinkles were confirmed in either one was evaluated as “Δ”, and the case where large wrinkles were confirmed in either case was evaluated as “×”.

(Solder reflow resistance test)
A SAW chip mounting substrate in which a SAW chip having the following specifications on which an aluminum comb-shaped electrode was formed was mounted on a glass substrate having a length of 50 mm, a width of 50 mm, and a thickness of 0.5 mm was produced under the following bonding conditions. The gap width between the SAW chip and the glass substrate was 30 μm.

<SAW chip>
Chip size: 1.2mm □ (thickness 150μm)
Bump material: Au bump, 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, ultrasonic output 2W

  On the obtained SAW chip mounting substrate, each multi-layer encapsulating resin sheet was pasted 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 releasing to atmospheric pressure, the multilayer encapsulating resin sheet was thermoset in a hot air dryer at 150 ° C. for 1 hour to obtain a sealed body. Thereafter, a moisture absorption operation was performed under the conditions of a temperature of 85 ° C., a humidity of 60% RH, and a time of 168 h, and the sealed body was passed through an IR reflow furnace that was set to maintain a temperature of 260 ° C. or higher for 10 seconds. About this sealing body, it was observed with the ultrasonic microscope whether peeling generate | occur | produced in the interface of a multilayer sealing resin sheet and a board | substrate. The case where no peeling occurred was evaluated as “◯”, the case where a minute peeling such that there was no practical problem occurred was evaluated as “Δ”, and the case where large peeling occurred was evaluated as “X”.

  As can be seen from Table 1, in the multilayer encapsulating resin sheets of Examples 1 to 3, neither laminated interface voids nor foaming after thermosetting was confirmed, and the solder reflow resistance was also good. In Example 4, although the lamination | stacking interface void and foaming after thermosetting were not confirmed, generation | occurrence | production of the wrinkle in a lamination process was confirmed. This is because the press by the laminator roll was too large for the thick multi-layer encapsulating resin sheet, so that the multi-layer encapsulating resin sheet was expanded when passing between the laminator rolls. It is inferred to be due to the occurrence of bias. In addition, the solder reflow resistance was slightly lowered because the adhesion of the multilayer encapsulating resin sheet to the substrate was lowered due to the generation of wrinkles. From this, it can be said that the pressure by the laminate roll is preferably 0.3 MPa or less in terms of suppressing wrinkles during lamination. On the other hand, in Comparative Example 1, the lamination surface temperature was too low, and in Comparative Example 2, since the degree of vacuum was not sufficient, both of the laminated interface voids and foaming after thermosetting occurred, and the solder reflow resistance was poor. It was.

DESCRIPTION OF SYMBOLS 1 Unit resin sheet 1a Support body 11 Multilayer sealing resin sheet 13 SAW chip 15 Sealing body 18 Electronic component package R Laminator roll S Lamination surface

Claims (6)

A coating process for producing a plurality of unit resin sheets by a coating method, and a laminating process for producing a multilayer encapsulating resin sheet by laminating the plurality of unit resin sheets,
The manufacturing method of the multilayer sealing resin sheet which performs the said lamination process in 85 degreeC or more of lamination surface temperature, and the pressure-reduced atmosphere of 10 kPa or less.   The manufacturing method of the sealing resin sheet of Claim 1 which performs the said lamination process using a roll-type laminator.   The method for producing a multilayer encapsulating resin sheet according to claim 1 or 2, wherein a pressure on the unit resin sheet in the laminating step is 0.05 to 0.3 MPa. The unit resin sheet includes an inorganic filler,
Content of the said inorganic filler in the said unit resin sheet is 70 volume% or more, The manufacturing method of the sealing resin sheet of any one of Claims 1-3.   The thickness of the said multilayer sealing resin sheet is 70 micrometers or more, The manufacturing method of the multilayer sealing resin sheet of any one of Claims 1-4. The multilayer sealing resin sheet whose size of the lamination | stacking interface void obtained by the manufacturing method of the multilayer sealing resin sheet of any one of Claims 1-5 is 100 micrometers or less.

Images