TWI819278B - Method for manufacturing electromagnetic wave shielding package using conductive composition - Google Patents

Abstract

The object of the present invention is to provide a method for manufacturing an electromagnetic wave shielding package, which can form a smooth spaced shielding layer with the upper surface of the sealing layer by hardening the conductive composition filled in the groove portion formed in the sealing layer. The solution is a manufacturing method of an electromagnetic wave shielding package, which has the following steps: a sealing step, mounting a plurality of electronic components on a substrate, filling the substrate with a sealing material and hardening it, thereby forming a sealing step for sealing the electronic components The sealing layer; the groove forming step, cutting the sealing layer between the plurality of electronic components to form a groove; the shielding step, forming a protective film on the sealing layer to at least cover the opening on the groove; the filling step , the front end of the nozzle of the device for discharging the conductive composition is pierced through the protective film and inserted into the groove, and a conductive composition equivalent to the volume of the groove is filled in the groove; and a hardening step is made to make the conductive The plastic composition hardens to obtain a barrier shield.

Description

Method for manufacturing electromagnetic wave shielding package using conductive composition

The present invention relates to a method for manufacturing an electromagnetic wave shielding package using a conductive composition.

Background technology

In electronic devices such as mobile phones and tablet computers, due to the requirements for miniaturization and high functionality, a packaging system (System in Package, SIP) that contains multiple semiconductor chips in one package and operates as a system is being sought. .

In such a packaging system, in order to achieve both compactness, lightweight and high functionality of electronic devices, the mounting density of electronic components is increased. However, if the mounting density is increased, there is a risk that adjacent electronic components may malfunction due to electromagnetic wave interference.

In response to the above problem, as a method of preventing malfunction of electronic components, the following method is known: forming grooves (grooves) between electronic components sealed with a sealing material, and filling the grooves with a conductive composition. This forms a shielding layer (so-called spacer shielding) by providing separation between electronic components.

As a method of filling the groove portion with the conductive composition, a vacuum printing method or a dispensing method can be used. Here, the so-called vacuum printing method refers to a method in which a chemical fiber mesh is used to make a plate, and ink is rubbed through the plate under vacuum to print on the printing surface of the object to be printed placed under the plate. In addition, the dispensing method refers to a method of applying the conductive composition by extruding it from the tip of a syringe-shaped nozzle.

In order to obtain sufficient shielding properties by the above method, the conductive composition must be Fill the groove from the bottom to the upper opening without any gaps. In addition, from the viewpoint of reducing the height of the packaging system, it is required that the conductive composition does not overflow from the groove and that the surfaces of the sealing layer and the spacer shielding layer are smooth.

However, when the vacuum printing method is used, the conductive composition may overflow from the opening on the groove part during printing. On the other hand, in the dispensing method, the conductive composition is ejected while moving the nozzle tip of the dispensing device in the horizontal direction along the groove. However, when the substrate is warped, it is difficult to make the connection between the substrate and the nozzle tip. The distance remains fixed, and it is difficult to fill the grooves with the conductive composition at a fixed discharge amount. In addition, since there is an error in the groove width or depth of the formed groove portion, there is a variation in the filling amount required for the discharge position of the conductive composition. Therefore, it is difficult to form a smooth spacer shield layer with the upper surface of the sealing layer, either because the filled conductive composition overflows from the upper opening of the groove portion or because the filling amount is insufficient.

Advanced technical documents

patent documents

[Patent Document 1] Japanese Patent Application Laid-Open No. 8-153738

[Patent Document 2] Japanese Patent Application Publication No. 2018-56186

[Patent Document 3] Japanese Patent Application Publication No. 3-269514

[Patent Document 4] Japanese Patent Application Laid-Open No. 8-124813

Summary of the invention

The present invention was made in view of the above, and an object thereof is to provide a method for manufacturing an electromagnetic wave shielding package by filling a groove formed in a sealing layer with a conductive composition from the bottom of the groove to the upper opening without any gaps. , and harden it to form a smooth spaced shielding layer above the sealing layer.

Furthermore, Patent Documents 1 to 4 describe a method of applying a conductive composition, but they do not describe forming a protective film so as to cover the opening on the groove portion formed in the sealing layer as in the present invention. method.

The manufacturing method of the electromagnetic wave shielding package of the present invention has the following steps: a sealing step, mounting a plurality of electronic components on a substrate, filling the substrate with a sealing material and hardening it, thereby forming a seal for sealing the electronic components layer; the groove forming step is to cut the sealing material between the plurality of electronic components to form a groove; the shielding step is to form a protective film on the sealing layer to at least cover the opening on the groove; the filling step is to The front end of the nozzle of the device for discharging the conductive composition pierces the protective film and is inserted into the groove, filling the groove with a conductive composition equivalent to the volume of the groove; and a hardening step to make the conductive composition The material is hardened to obtain a spacer shield.

In the manufacturing method of the electromagnetic wave shielding package of the present invention, the protective film located at the end of the groove portion may also be provided with a hole for exhaust.

The manufacturing method of the electromagnetic wave shielding package of the present invention may also include: in the above-mentioned filling step, after discharging a conductive composition equivalent to the volume of the above-mentioned groove part, the front end of the nozzle is pulled out from the above-mentioned groove part while discharging an equivalent amount. A conductive composition in the volume of the nozzle front end inserted into the groove.

According to the method of manufacturing an electromagnetic wave shielding package of the present invention, an electromagnetic wave shielding package having excellent shielding properties and having a smooth shielding layer spaced above the sealing layer can be obtained.

10:Substrate

11: Ground circuit

12:Sealing layer

13: Groove

14:Protective film

15: Conductive composition

16: Nozzle front end

20: Interval shielding layer

21: Upper face

22: Bottom face

23:Shielding layer

30: Electronic parts

A: Individualized package on the substrate

B: Monolithized shielded package

FIG. 1 is a schematic diagram showing the filling step of the manufacturing method according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the steps of forming a shielding layer on the surface of a package in a manufacturing method according to an embodiment of the present invention.

3 is a schematic cross-sectional view of the groove portion formed by the sealing layer of the sample substrate used in the embodiment.

FIG. 4 is a top view photograph of Sample 1 produced in the Example.

Figure 5 is a cross-sectional photograph of sample 1 prepared in the Example.

FIG. 6 is an X-ray photograph of Sample 1 produced in the Example taken from above at an angle of 45°.

FIG. 7 is a top view photograph of Sample 2 produced in Comparative Example.

Figure 8 is a cross-sectional photograph of sample 2 produced in the comparative example.

Figure 9 is an X-ray photograph of sample 2 produced in the comparative example taken from above at an angle of 45°.

Form used to implement the invention

The manufacturing method of the electromagnetic wave shielding package according to one embodiment of the present invention, as mentioned above, has the following steps: a sealing step, mounting a plurality of electronic components on a substrate, filling the substrate with a sealing material and hardening it, thereby forming a A sealing layer for sealing the above-mentioned electronic components; a groove forming step of cutting the sealing layer between the plurality of electronic components to form a groove; and a shielding step of covering at least the opening on the groove above the sealing layer. Forming a protective film; in the filling step, the front end of a nozzle of a device for discharging the conductive composition is pierced through the protective film and inserted into the groove, and a conductive composition equivalent to the volume of the groove is filled in the groove; and In the hardening step, the conductive composition is hardened to obtain a spacer shielding layer.

The above sealing steps are not particularly limited and can be implemented according to common methods. The sealing material used here can be commonly used and is not particularly limited.

The above-mentioned groove forming step is not particularly limited and can be carried out according to common methods. In the conventional vacuum printing method or dispensing method, from the viewpoint of preventing the conductive composition from overflowing from the opening on the top of the groove, the shape of the groove is adopted such that the width of the opening on the top of the groove is wider than the groove width on the bottom of the groove. (so-called two-stage groove), but according to the manufacturing method of this embodiment, it is not limited to this, and various shapes can be adopted.

The above-mentioned shielding step only needs to form a protective film in such a manner that at least the opening on the upper surface of the groove is covered.

The protective film can be appropriately selected based on the composition of the conductive composition or the curing temperature of the conductive composition, the device settings when filling the conductive composition, the filling volume, and the design of the groove. Regarding the material of the protective film, any commonly used material can be used without particular limitations. Examples include: polyethylene, polyester, polysilicone rubber, polyimide, polyethylene terephthalate, polypropylene, polyethylene Ethylene naphthalate, nylon, polyphenylene sulfide, fluororesin, polyetheretherketone, etc. As such a protective film, for example, "7414" manufactured by 3M Japan Co., Ltd. can be used.

The above filling steps are explained using Figure 1. Figure 1 shows that the ground circuit 11 has been formed on the substrate 10, and the substrate 10 and the ground circuit 11 have been sealed by the sealing layer 12, and a groove 13 is formed in the sealing layer 12, and the groove 13 is filled. Diagram of the steps of conductive composition 15. In this embodiment, since the truncated cone-shaped nozzle front end 16 is used, if the protective film 14 is to be pierced at one time, the protective film 14 may stretch and create a gap between the protective film 14 and the nozzle front end 16. There is a risk that the conductive composition 15 leaks from this gap. Therefore, first, as shown in FIGS. 1(a) and (b) , the nozzle front end 16 is pressed into the groove part 13 where the protective film 14 has been formed, and the protective film 14 is shaped. The pushing amount or the pushing speed at this time can be appropriately adjusted according to the shape of the nozzle tip 16 or the shape of the groove portion 13 and the type of the protective film 14 . Then, the nozzle tip 16 is temporarily separated from the substrate 10 . In addition, in this specification, the "press-in amount" refers to the distance between the upper surface of the sealing layer and the front end of the nozzle inserted into the groove.

Next, as shown in FIGS. 1(c) and (d) , the nozzle tip 16 is slowly pressed into the groove 13 to pierce the protective film 14 . By pressing in twice in this manner, the nozzle front end 16 can pierce the protective film 14 without creating a gap between the protective film 14 and the nozzle front end 16 . The amount of press-in or the speed of press-in at this time can be adjusted appropriately according to the shape of the nozzle tip 16 or the shape of the groove portion 13 and the type of the protective film 14. However, it is preferable that the amount of press-in is larger than that of the first press-in and the pressure is greater than that of the first press-in. The insertion speed is slower than the first pressing.

As shown in FIG. 1(e) , the conductive composition 15 corresponding to the volume of the groove portion 13 is discharged. The discharged conductive composition 15 fills every corner of the space defined by the groove portion 13 and the protective film 14 covering the opening of the groove portion 13 . In the previous distribution method, when the aspect ratio (depth/groove width) of the groove portion 13 is large, it is difficult to The conductive composition 15 is filled without voids. However, according to the filling method of this embodiment, the conductive composition 15 can be filled without voids even in the groove portion 13 having an aspect ratio of 10 to 20, for example.

As shown in FIG. 1(e) , when filling the conductive composition 15 , depending on the shape of the nozzle tip 16 or the amount of pressing of the nozzle tip 16 into the groove 13 , there may be a problem corresponding to the insertion into the groove 13 . The case of a concave portion in the volume of the nozzle tip 16. At this time, if necessary, as shown in FIG. 1( f ), the conductive composition equivalent to the volume of the nozzle front end 16 inserted into the groove 13 is ejected while pulling out the nozzle front end 16 from the groove 13 . 15, whereby a recess equivalent to the volume of the inserted nozzle front end 16 can be filled.

The device used when discharging the conductive composition 15 is not particularly limited as long as it can be used for the dispensing method. An example is the valve "DV-" used in the dispenser "S2-920N-P" manufactured by Nordson ASYMTEK Co., Ltd. 8000". The device settings when discharging the conductive composition 15, such as the valve temperature and substrate temperature, can be appropriately adjusted according to the composition or viscosity of the conductive composition 15.

The speed at which the conductive composition 15 is discharged (the discharge amount per second) can be appropriately adjusted depending on the shape of the groove portion 13 formed in the sealing layer 12 or the viscosity of the conductive composition 15 .

The conductive composition 15 is not particularly limited as long as it can be used to form the compartment shielding layer 20 , but it is preferably one that does not contain a solvent. When a solvent is included, there is a risk that the solvent may evaporate when the conductive composition 15 is hardened and voids may be generated.

In addition, in the previous dispensing method, from the viewpoint of filling properties, the viscosity of the conductive composition at 25°C needs to be adjusted to 600dPa. s or less, but according to the filling method of this embodiment, even a conductive composition with a higher viscosity can be used. Specifically, it can be adjusted appropriately according to the type of device used, the shape of the groove portion 13 formed in the sealing layer 12, etc., but as a general standard, the viscosity of the conductive composition 15 at 25°C is preferably 1500 dPa. ． s or less, preferably 1000dPa. s or less. is 1500dPa． When s or less, the conductive composition 15 can flow from the inserted nozzle tip 16 along the groove 13, and excellent filling properties into the groove 13 can be easily obtained. Furthermore, the viscosity can be measured according to JIS K7117-1 using a single cylindrical rotational viscometer (so-called B-type or BH-type viscometer) using spindle No. 7 at 10 rpm. Only The viscosity can be measured with a single cylindrical rotational viscometer, no matter how low it is.

The above-mentioned hardening step is not particularly limited as long as the hardening conditions are appropriately set according to the conductive composition 15 used. Furthermore, the protective film 14 is preferably peeled off after the hardening step.

According to the manufacturing method of the electromagnetic wave shielding package of this embodiment, the conductive composition 15 can be filled into every corner of the groove 13 without gaps, and the conductive composition 15 will not overflow from the upper opening of the groove 13 or By hardening the conductive composition 15 to generate dents, a smooth spacer shield layer 20 having no step difference from the upper surface of the sealing layer 12 can be obtained without polishing or the like.

In addition, in the previous dispensing method, for example, when filling the conductive composition 15 into the groove portion 13 that has a complex shape such as a radially extending shape or a curved shape such as an S, it is necessary to control the nozzle tip with high positional accuracy. Department 16. In the manufacturing method of the electromagnetic wave shielding package of this embodiment, unlike the previous dispensing method, it is only necessary to move the nozzle tip 16 up and down relative to the substrate 10, and there is no need to move it horizontally along the groove portion 13. Therefore, even when the groove portion 13 has a complex shape as described above, the conductive composition 15 can be filled and hardened simply and without gaps, thereby obtaining a smooth surface with excellent shielding properties and the upper surface of the sealing layer 12 . Spacer shield 20.

<Example of changes>

In the above embodiment, the example in which the nozzle front end 16 is pressed in twice so that the nozzle front end 16 pierces the protective film 14 without creating a gap between the protective film 14 and the nozzle front end 16 is explained. However, this is not the case. It is not limited to this, and the protective film 14 with pre-opened holes may be used, and there may also be a step of using a needle to open holes in the protective film 14 .

In addition, since the shape of the nozzle tip 16 is a truncated cone, the protective film 14 may stretch and a gap may be generated between the protective film 14 and the nozzle tip 16. However, depending on the shape of the nozzle tip 16, There may be cases where there is no risk of a gap occurring between the protective film 14 and the nozzle tip 16 . Specifically, for example, the shape of the nozzle front end portion 16 is like an injection needle, the front end portion is cut obliquely, and the cut surface has a knife surface. When such a nozzle is used, since the nozzle front end 16 is easily pierced through the protective film 14, the protective film 14 and There is no risk of a gap occurring between the nozzle tip portions 16, so there is no need to push the nozzle tip portion 16 in twice.

The manufacturing method of the electromagnetic wave shielding package of the present invention may also provide a hole for exhaust in the protective film 14 located at the end of the groove portion 13 . Even if the groove portion 13 only opens on the sealing layer 12 (the groove portion 13 is not connected to the side surface of the sealing layer 12), and the opening on the groove portion 13 is completely sealed by the protective film 14, by setting the protective film 14 in this way, The exhaust holes can discharge the air that has nowhere to go when filling the conductive composition 15 to the outside of the groove portion 13, and the conductive composition 15 can be filled into every corner of the groove portion 13 without gaps.

The manufacturing method of the electromagnetic wave shielding package of the present invention may also include the following steps: after peeling off the protective film 14, coating a conductive composition on the surface of the package and hardening it to form a shielding layer on the surface of the package Steps; and steps of monolithizing the package of each electronic component.

Specifically, according to the design of the packaging system, as shown by the arrow in FIG. 2(a) , the sealing layer 12 is cut between the electronic components 30 without the spacing shielding layer 20 to form grooves. Through these grooves The packages of the electronic components 30 on the substrate 10 are individualized. Symbol A indicates individualized packages. At least part of the ground circuit 11 is exposed from the wall forming the trench, and the bottom of the trench does not completely penetrate the substrate 10 .

Next, as shown in FIG. 2(b) , the conductive composition is sprayed in a mist form using a well-known spray gun or the like, and is evenly coated on the surface of the package. Then, heating is performed to fully harden the conductive composition, and the shielding layer 23 is formed on the surface of the package. The method of applying the conductive composition is not limited to spray coating, and may be a vacuum printing method, or a metal plating method or the like to form a metal layer as the shielding layer 23 .

Next, as shown by the arrow in FIG. 2(c) , the substrate 10 is cut with a dicing saw or the like along the groove bottom of the pre-single package to obtain the singulated package B. .

In FIG. 2 , the structure of the electromagnetic wave shielding package in which the ground circuit 11 and the shield layer 23 are connected is shown. However, it may also be a structure in which the ground circuit 11 and the space shield layer 20 are connected, or the ground circuit 11 and the space shield layer 20 and the shield layer 23 may be connected. The structure that connects the two.

Furthermore, in FIG. 2(a) , although the ground circuit 11 and the sealing layer 12 are cut to form grooves, However, it is not limited to this, and only the sealing layer 12 may be cut to form the groove portion. By forming the groove portion in this way, the ground circuit 11 can be exposed from the side surface of the singulated package B.

<Conductive composition>

An example of a conductive composition suitable for use as a spacer shield is one containing 5 to 20 parts by mass of a dimer acid type epoxy resin and 400 to 800 parts by mass of a conductive filler relative to 100 parts by mass of the epoxy resin.

Epoxy resins other than dimer acid type epoxy resin may have one or more epoxy groups in the molecule, and two or more types may be used in combination. Specific examples include bisphenol A-type epoxy resin, brominated epoxy resin, bisphenol F-type epoxy resin, novolac-type epoxy resin, alicyclic epoxy resin, and epoxypropylamine-type epoxy. Resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, heterocyclic epoxy resin, etc., among these, glycidyl amine type epoxy resin or ring-based epoxy resin is preferred. Oxypropyl ether type epoxy resin.

The epoxy equivalent of epoxy resins other than dimer acid type epoxy resin is not particularly limited, but is preferably 1500 g/eq or less, and more preferably 20 to 1000 g/eq. When the epoxy equivalent is within the above range, it is easy to obtain a conductive composition with a good balance of heat resistance, viscosity, and adhesion.

The dimer acid type epoxy resin can be an epoxy resin with more than one epoxy group in the molecule and the dimer acid has been modified. For example, the epoxy propyl modified compound of dimer acid can be cited. Two or more types can be used together. As these resins, for example, those represented by the following general formulas (1) and (2) can be used.

[Chemical formula 1]

n1 to n5 in formulas (1) and (2) respectively independently represent integers from 3 to 9.

n1 represents an integer of 3 to 9, preferably an integer of 4 to 8, more preferably 5 to 7, and more preferably 7. n2 represents an integer from 3 to 9, preferably an integer from 5 to 9, more preferably 7 or 8, more preferably 7. n3 represents an integer from 3 to 9, preferably an integer from 4 to 8, more preferably 6 or 7, more preferably 6. n4 represents an integer from 3 to 9. n5 represents an integer from 3 to 9, preferably an integer from 4 to 8, more preferably 5 or 6, more preferably 5.

By containing such a dimer acid type epoxy resin, the viscosity or thixotropic index (TI value) of the conductive composition can be easily reduced, and excellent filling properties into the groove portion 13 formed in the sealing layer 12 can be easily obtained.

The epoxy equivalent of the dimer acid type epoxy resin is not particularly limited, but is preferably 80~1500g/eq, and more preferably 200~1000g/eq. When the epoxy equivalent is within the above range, it is easy to obtain a conductive composition with a good balance of heat resistance, viscosity, and adhesion.

The content of the conductive filler is not particularly limited as long as it is 400 to 800 parts by mass relative to 100 parts by mass of the epoxy resin, but is preferably 450 to 600 parts by mass. Within the above range, it is easy to obtain A conductive composition that is excellent in shielding properties and fillability into the groove portion 13 formed in the sealing layer 12 .

The conductive filler is preferably copper powder, silver powder, gold powder, silver-coated copper powder or silver-coated copper alloy powder. One of these may be used alone or two or more may be used in combination. From the viewpoint of cost reduction, copper powder is preferred. , silver-coated copper powder or silver-coated copper alloy powder.

The silver-coated copper powder has copper powder and a silver layer or silver-containing layer covering at least a part of the copper powder particles. The silver-coated copper alloy powder has copper alloy particles and a silver layer or a silver-containing layer covering at least a part of the copper alloy particles. Silver layer person. For example, the copper alloy particles have a nickel content of 0.5 to 20 mass %, a zinc content of 1 to 20 mass %, and the remainder is composed of copper. The remainder of the copper may also contain unavoidable impurities. By using copper alloy particles having a silver coating layer in this manner, an electromagnetic wave shielding package excellent in shielding properties and discoloration resistance can be obtained.

Examples of the shape of the conductive filler include: flake (scale), dendritic, spherical, fibrous, irregular shape (polyhedron), etc., thereby obtaining a shielding layer with lower resistance value and improved shielding properties. From the viewpoint of improving filling properties, a spherical shape is preferred.

The conductive filler is preferably a conductive filler with an average particle diameter of 1 to 8 μm. It is more preferable to use a combination of a conductive filler (A) with an average particle diameter of 4 to 8 μm and a conductive filler (A) with an average particle diameter that is 2 μm smaller than the conductive filler. The above conductive filler (B). Here, the average particle diameter refers to the number-based average particle diameter D50 (median particle diameter) measured by a laser diffraction scattering particle size distribution measuring method.

The conductive filler (A) has an average particle size of 4 to 8 μm, has good dispersion and can prevent aggregation, and the connectivity and shielding properties of the package and the ground circuit are likely to be good.

Since the average particle diameter of the conductive filler (B) is smaller than that of the conductive filler (A) by more than 2 μm, the gaps between the conductive fillers (A) can be filled, so the shielding property against electromagnetic waves of 100 MHz to 1 GHz can be improved. And a conductive composition with low viscosity can be obtained.

The content ratio ((A):(B)) of the conductive filler (A) and the conductive filler (B) is preferably 97:3~50:50, preferably 95:5~70:30 in terms of mass ratio. .

Moreover, when the conductive filler (A) is spherical, the tap density of the conductive filler (A) is preferably 3.5 to 7.0 g/cm ³ . When the tap density is within the above range, the conductivity of the shielding layer is more likely to be good.

Moreover, when the conductive filler (B) is spherical, the tap density of the conductive filler (B) is preferably 3.5 to 7.0 g/cm ³ . When the tap density is within the above range, the conductivity of the shielding layer is more likely to be good.

The conductive composition of a preferred embodiment may contain an epoxy resin hardener. Examples of epoxy resin hardeners include phenol-based hardeners, imidazole-based hardeners, amine-based hardeners, and cationic hardeners. These may be used individually by 1 type, and may use 2 or more types together.

Examples of the phenol-based hardener include phenol novolac, naphthol-based compounds, and the like.

Examples of imidazole-based hardeners include imidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, and 1-benzyl -2-Phenylimidazole, 2-ethyl-4-methyl-imidazole, 1-cyanoethyl-2-undecylimidazole.

Examples of amine-based hardeners include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenylthione. amine.

Examples of cationic hardeners include onium compounds represented by the following: amine salt of boron trifluoride, p-methoxyphenyldiazonium hexafluorophosphate, and diphenylphosphonium hexafluorophosphate. , triphenylsulfonium salt, tetra-n-butylphosphonium tetraphenylborate, tetra-n-butylphosphonium-o,o-diethyl dithiophosphate.

The content of the hardener is preferably 0.3 to 40 parts by mass, preferably 0.5 to 35 parts by mass relative to 100 parts by mass of the epoxy resin. When the content of the hardener is 0.3 parts by mass or more, the conductive composition can be fully hardened, and it is easy to obtain a shielding layer with good conductivity and excellent shielding effect. When the content of the hardener is 40 parts by mass or less, storage stability is easily obtained. Excellent conductive composition.

The conductive composition of a preferred embodiment may also contain well-known additives such as defoaming agents, thickeners, adhesives, fillers, flame retardants, and colorants.

[Example]

Hereinafter, the contents of the present invention will be described in detail based on examples, but the present invention is not limited to in the following examples. In addition, in the following, unless otherwise stated, "parts" or "%" are based on mass.

[Preparation of conductive composition]

The following 48 parts by mass of epoxy resin (a), 42 parts by mass of epoxy resin (b), 10 parts by mass of dimer acid type epoxy resin, 450 parts by mass of conductive filler (A), and 50 parts by mass of B), 6 parts by mass of the hardener (a) and 11 parts by mass of the hardener (b) were mixed to obtain a conductive composition. Details of each ingredient used are as follows.

． Epoxy resin (a): Glycidylamine type epoxy resin, "EP-3905S" manufactured by ADEKA Co., Ltd., epoxy equivalent = 95g/eq

． Epoxy resin (b): Glycidyl ether type epoxy resin, "ED502" manufactured by ADEKA Co., Ltd., epoxy equivalent = 320g/eq

． Dimer acid type epoxy resin: used in the above formula (2) where n1=7, n2=7, n4=4, n5=5.

． Conductive filler (A): silver particles, D50=4μm, spherical

． Conductive filler (B): silver particles, D50=2μm, spherical

． Hardener (a): Imidazole-based hardener, "2E4MZ" manufactured by Shikoku Chemical Industry Co., Ltd.

． Hardener (b): Phenolic hardener, "Tamanol 758" manufactured by Arakawa Chemical Industry Co., Ltd.

In accordance with JIS K7117-1, the viscosity of the conductive composition obtained above was measured at 25°C using a single cylindrical rotational viscometer (so-called B-type viscometer) using spindle No. 7 at 10 rpm. The result was that the viscosity was 780 dPa. s.

[Example]

Using the sample substrate shown in FIG. 3, sample 1 is produced by the manufacturing method of the electromagnetic wave shielding package of the present invention. As a sample substrate, a ground circuit 11 is formed on the substrate 10 , the substrate 10 and the ground circuit 11 are sealed by a sealing layer 12 , and a groove 13 is formed in the sealing layer 12 .

"7414" manufactured by 3M Japan Co., Ltd. was adhered so as to cover the upper surface of the groove portion 13 of the sample substrate. Then, use the distributor "S2-920N- P" and valve "DV-8000", first press the front end of the nozzle into the groove 13 at a press speed of 300mm/second and a press amount of 0.05mm, hold for 0.1 seconds, and then temporarily remove the nozzle front end from the groove 13, and then press it again The front end of the nozzle was pressed into the groove portion 13 at a pushing speed of 5 mm/second and a pushing amount of 0.08 mm to pierce the protective film 14 . Next, the conductive composition obtained above was filled into the groove portion 13 under the following conditions.

<Settings of distribution device>

Discharge volume: 1.3×10 ^-4 cm ³ /second

Nozzle inner diameter: 75μm

The distance between the sample substrate and the front end of the nozzle: 0.08mm (the front end of the nozzle is inserted into the groove 13)

<Comparative example>

Using the sample substrate shown in FIG. 3 , the conductive composition obtained above is filled into the groove portion 13 using the previous dispensing method. The equipment used is the same as that of the above embodiment. The device settings are as follows.

<Settings of distribution device>

Discharge volume: 1.3×10 ^-4 cm ³ /second

Nozzle inner diameter: 75μm

The distance between the sample substrate and the front end of the nozzle: 0.05mm (the front end of the nozzle is not inserted into the groove 13)

Nozzle feed speed: 1.2mm/second

The obtained samples 1 and 2 were heated at 80°C for 60 minutes and further at 160°C for 60 minutes to harden the conductive composition. For the obtained samples 1 and 2, after hardening, the groove portion 13 was observed using the X-ray transmission device "Y.Cheetah μHD" manufactured by YXLON International under the following measurement conditions to confirm the presence or absence of voids.

In the embodiment, as shown in FIGS. 4 to 6 , it can be seen that the conductive composition is filled from the bottom surface of the groove portion to the upper opening portion without gaps, and the upper surface portion 21 of the spacer shielding layer is formed in the same shape as the upper surface of the sealing layer without polishing or the like. Smooth spacer shield.

On the other hand, in the comparative example, as shown in Figs. 7 and 8, the upper portion 21 of the spacer shield layer , the conductive composition overflows from the groove, and the conductive composition cannot fully fill the groove, resulting in a concave portion.

Furthermore, as shown in FIGS. 8 and 9 , the conductive composition is not fully filled in the spacer shield layer bottom portion 22 and voids are generated. In the X-ray photograph of FIG. 9 , it can be seen that the upper side of the spacer shielding layer 20 represents the upper portion 21 and the lower side represents the bottom portion 22 . Since the bottom portion 22 is not linear, a wide range of gaps are generated in the bottom portion 22 .

10:Substrate

11: Ground circuit

12:Sealing layer

13: Groove

14:Protective film

15: Conductive composition

16: Nozzle front end

Claims (3)

A method for manufacturing an electromagnetic wave shielding package, which has the following steps: The sealing step is to mount a plurality of electronic components on a substrate, fill the substrate with a sealing material and harden it, thereby forming a sealing layer for sealing the aforementioned electronic components; The groove forming step is to cut the sealing layer between the plurality of electronic components to form a groove; In the shielding step, a protective film is formed on the sealing layer to cover at least the opening on the groove; In the filling step, the front end of the nozzle of the device for discharging the conductive composition is pierced through the protective film and inserted into the groove, and a conductive composition equivalent to the volume of the groove is filled in the groove; and In the hardening step, the aforementioned conductive composition is hardened to obtain a spacer shielding layer. In the method of manufacturing an electromagnetic wave shielding package according to claim 1, the protective film is provided with a hole for exhausting air in front of the end portion of the groove portion. The method for manufacturing an electromagnetic wave shielding package according to claim 1 or 2, wherein in the filling step, after discharging the conductive composition equivalent to the volume of the groove, the front end of the nozzle is pulled out from the groove. The conductive composition is discharged corresponding to the volume of the front end portion of the nozzle before being inserted into the groove portion.