JP2023138301A - Method for forming electromagnetic wave shield, method for manufacturing structure, and structure - Google Patents

Abstract

To reduce peeling of and cracks in a shield layer 200.SOLUTION: A method for forming a shield layer 200 includes the steps of: discharging, by an ink jet head 400, an ink 500 including conductive material to a top face 102 and a side face 104 of an outer peripheral surface 100 of a substrate to form a conductive layer 210 including a plurality of openings 220; and forming an insulating layer 230 that is formed from a surface of the conductive layer 210 to the outer peripheral surface 100 of the substrate through the plurality of openings 220 and is bonded to the outer peripheral surface 100 of the substrate.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for forming an electromagnetic shield, a method for manufacturing a structure, and a structure.

Patent Document 1 discloses, in a semiconductor integrated circuit mounted on a printed circuit board on which a wiring pattern is formed and connected to the wiring pattern via a plurality of terminals, a surface of the semiconductor integrated circuit on the opposite side of the printed circuit board. A semiconductor device having an electromagnetic noise shielding part, characterized in that it has a shielding part that shields electromagnetic noise, and a connecting part for connecting the shielding part and the ground on the printed circuit board. Integrated circuits are described.

Patent Document 2 describes an EMI shield in which the conductive layer includes inkjet printing.

Patent Document 3 discloses that an undercoat layer 5 and an ink receiving layer 6 are provided on one surface of a PET base layer 4, and a conductive paste ink is screen printed on the ink receiving layer 6 and then baked. An electromagnetic shielding material 1 is described in which a lattice-shaped electromagnetic shielding mesh layer 7 is provided.

Japanese Patent Application Publication No. 2001-127211 US Patent No. 9282630 Patent No. 5703050

An object of the present invention is to improve the shielding performance and durability of an electromagnetic shield.

A method for forming an electromagnetic shield according to claim 1 of the present invention is to form a conductive layer including a plurality of openings on the top and side surfaces of an object for which an electromagnetic shield is to be formed, such as an electronic component or a semiconductor package containing the electronic component. and a step of forming an insulating layer that is continuously formed from the surface of the conductive layer to the surface of the object through a plurality of openings and adhered to the surface of the object.

According to claim 1 of the present invention, the shielding performance and durability of the electromagnetic shield can be improved.

FIG. 1 is an explanatory diagram of an electronic device according to an embodiment of the present invention. FIG. 3 is an explanatory diagram of another electronic device according to the present embodiment. FIG. 3 is an explanatory diagram of a method for forming an electromagnetic shield according to the present embodiment. It is a sectional view of the electromagnetic wave shield concerning this embodiment. It is an explanatory view of a formation process of an electromagnetic wave shield concerning this embodiment. It is a figure which shows the printing patterns A and B of Table 4 in the electromagnetic wave shield based on this embodiment. It is a figure which shows the printing pattern C of Table 4 in the electromagnetic wave shield based on this embodiment. It is a figure which shows the printing pattern D of Table 4 in the electromagnetic wave shield based on this embodiment. It is a figure which shows the other example of the printing pattern D of Table 4 in the electromagnetic wave shield based on this embodiment. It is a figure showing the evaluation method of the electromagnetic wave shielding effect concerning this embodiment.

A printed wiring board (PWB) used for high-speed communications such as 5G and autonomous driving without any electronic components attached, and a state where the electronic components are soldered to operate as an electronic circuit. Printed circuit boards (PCBs) are required to have high reliability, and control technology using electromagnetic waves generated from electronic components and wiring is known. Furthermore, as products become smaller and lighter, PCBs and the like are required to be thinner and lighter, and techniques for electromagnetic shielding of PCBs and electronic components used in PCBs are also known.

In other words, shielding films, metal caps, conductive paints, etc. are used as electromagnetic shields for structures containing electronic components, such as IC chips, capacitors, resistors, diodes, and solenoids, and semiconductor packages that house electronic components in electronic devices. Covering with conductors or electromagnetic wave absorbers is also practiced.

FIG. 1 is an explanatory diagram of an electronic device according to an embodiment of the present invention.

As shown in FIG. 1A, the electronic device 1 includes a shield layer 200 and a protective layer 300 on the outer peripheral surface 100 of the semiconductor package 110. The shield layer 200 is electrically connected to a ground portion 100G included in the semiconductor package 110. The protective layer 300 may be omitted or may be formed integrally with the shield layer 200.

As shown in FIG. 1(b), the shield layer 200 shown in FIG. 1(a) includes a conductive layer 210 formed in a predetermined pattern on the upper surface and side surfaces of the outer peripheral surface 100 of the semiconductor package 110, which is the target object. An insulating layer 230 covers this.

As shown in FIG. 1(c), the configuration shown in FIG. 1(b) has, for example, an inkjet head 400 installed horizontally with respect to the object, and inkjet heads 401 and 402 installed diagonally left and right. A shield layer 200 is formed on the upper surface and side surfaces of the outer peripheral surface 100 of the semiconductor package 110 by discharging ink 500 , 501 , and 502 containing a conductive material onto the upper surface and side surfaces of the outer peripheral surface 100 .

Here, the inks 500, 501, and 502 are examples of liquid compositions containing conductive materials, and the inkjet heads 400, 401, and 402 are examples of application units that apply the liquid compositions. Further, the shield layer 200 is an example of a conductive layer.

FIG. 2 is an explanatory diagram of another electronic device according to this embodiment.

As shown in FIG. 2(a), the electronic device 1 includes an electronic component 120 and a board 130. The connection portion 125 provided on the electronic component 120 is electrically connected to the wiring 135 provided on the substrate 130 by attaching the electronic component 120 to the substrate 130.

The electronic component 120 includes a shield layer 200 on the outer peripheral surface 100, and the shield layer 200 is connected to the ground portion 100G of the electronic component 120. When the electronic component 120 is attached to the substrate 130, the shield layer 200 is connected to the ground portion 100G of the electronic component 120. The wiring 145 provided in the electronic component 120 and the ground portion 100G provided in the electronic component 120 are electrically connected via the connection portion 155. Electronic component 120 is an example of an electronic module. Alternatively, the shield layer 200 may be configured separately from the electrical/electronic component 120. In this case, a structure including the electronic component 120 and the shield layer 200 is configured.

As shown in FIG. 2B, in this embodiment, inkjet heads 400, 401, and 402 eject ink 500, 501, and 502 containing a conductive material onto the top and side surfaces of the outer peripheral surface 100 of the electronic component 120. By doing so, the shield layer 200 is formed on the upper surface and side surfaces of the outer peripheral surface 100.

Here, in order to save space, reduce weight, and improve productivity, electromagnetic shielding is already known in which conductive paint is applied directly to electronic components using an inkjet method.

US Pat. No. 9,282,630 describes an EMI shield in which the conductive layer is printed by inkjet printing, but there is no shielding effect due to noise leakage from the side surfaces of the shield layer 200, and the coating on the side surfaces of the shield layer 200 There is no mention of peeling or cracking.

The smaller the volume ratio of the shield layer 200, the higher the shielding effect, and the thickness of the shield layer 200 can be made thinner. When forming the shield layer 200 with low volume resistance by coating or the like, heating is required.

Here, damage such as peeling or cracking of the shield layer 200 may occur due to stress due to the difference in thermal expansion between the upper and lower bonding surfaces of the shield layer 200 due to heat generated during film formation of the shield layer 200 or during use of the electronic device 1. There have been problems in that the adhesive strength of the shield layer 200 itself is not sufficient to begin with, and the durability of the film is poor when thinned.

This embodiment aims at reducing noise leakage, peeling, and cracking from the side surfaces of the shield layer 200. More specifically, this embodiment improves the shielding effect of the conductive layer of the electromagnetic shield layer formed directly on electronic components using the inkjet method, improves the physical durability of the shield layer by improving adhesive strength, and reduces weight by making the conductive layer thinner. The purpose is to save resources by coating the conductive layer in a pattern.

FIG. 3 is an explanatory diagram of a method for forming an electromagnetic shield according to this embodiment.

As shown in FIG. 3A, the inkjet head 400 is arranged to eject ink 500 in the normal direction of the upper surface 102 of the outer peripheral surface 100 of the base material, and the inkjet heads 401 and 402 The inkjet head 400 is disposed on the left and right sides of the drawing with the inkjet head 400 as the center, and inclined with respect to the inkjet head 400 so as to eject the inks 501 and 502 in a direction intersecting the upper surface 102 and the side surface 104. Here, since the position of landing on the outer circumferential surface 100 changes depending on the environment such as temperature and airflow, the inkjet heads 401 and 402 do not have to be arranged symmetrically in the left-right line in the figure with the inkjet head 400 at the center.

Then, the inkjet heads 400, 401, and 402 apply inks 500, 501, and 502 to the outer circumferential surface 100 placed on the mounting table 600 while moving the mounting table 600 in the direction of the arrow in the figure. As a result, the shield layer 250 is formed on the upper surface 102 of the outer circumferential surface 100, and the shield layer 260 is formed on the side surface 104 of the outer circumferential surface 100.

FIG. 3B is a top view of the objects placed on the mounting table 600, and the objects are arranged in a diamond shape 100H with respect to the mounting table 600.

FIG. 4 is a cross-sectional view of the electromagnetic shield according to this embodiment.

The shield layer 200 of this embodiment includes at least a conductive layer 210 that reflects electromagnetic waves, and an insulating layer 230 that protects the conductive layer 210 and has insulation properties. The insulating layer 230 may be configured as the protective layer 300 shown in FIGS. 1 and 2. The conductive layer is electrically connected to the ground portion 100G described in FIGS. 1 and 2. When the target electronic circuit component has a conductive part connected to the electronic circuit other than the ground part 100G, an undercoat layer 150 made of an insulating resin is provided to ensure insulation, and a conductive layer and an insulating layer are sequentially formed on the undercoat layer 150 made of an insulating resin. Provide layers.

In FIG. 4A, a conductive layer 210 included in the shield layer 200 is provided on the top and side surfaces of the outer peripheral surface 100 of the base material, and a plurality of openings 220 are formed in the conductive layer 210.

The insulating layer 230 included in the shield layer 200 also includes a covering part 234 that covers the pillar part 212 of the conductive layer 210, and a filling part 232 that is provided continuously with the covering part 234 and fills inside the plurality of openings 220. and is bonded to the outer circumferential surface 100 at the filling portion 232.

In FIG. 4B, the outer peripheral surface 100 includes an insulating undercoat layer 150 formed on the surface of the semiconductor package 110 or the electronic component 120, and the conductive layer 210 included in the shield layer 200 is formed on the undercoat layer 150. 150 , and a plurality of openings 220 are formed in the conductive layer 210 .

The insulating layer 230 included in the shield layer 200 also includes a covering part 234 that covers the pillar part 212 of the conductive layer 210, and a filling part 232 that is provided continuously with the covering part 234 and fills inside the plurality of openings 220. and is adhered to the surface of the undercoat layer 150 at the filling portion 232.

As described above, in this embodiment, the conductive layer 210 is sandwiched between the covering portion 234 and the outer circumferential surface 100 of the base material or the surface of the undercoat layer 150 that are integrated via the filling portion 232, thereby creating a shield. Peeling and cracking of the layer 200 can be reduced.

The thickness of the conductive layer 210 in this embodiment is 10 um or less. This is because a thickness of 1 um or less provides a sufficient electromagnetic shielding effect, and if it is too thick, the cost will increase. In the inkjet coating method, the amount of coating can be adjusted arbitrarily, so even if the outer circumferential surface 100 of the base material (electronic board) has unevenness, the thickness of the conductive layer 210, shield layer 200, and filling part 232 will hardly change. Sufficient shielding effect and adhesion can be maintained.

Further, the fact that the solid content of the ink containing a conductive material for forming the conductive layer 210 is 50% or less also makes it difficult to form a diagonal shape with a thin film thickness.

FIG. 5 is an explanatory diagram of the process of forming the electromagnetic shield according to this embodiment. FIG. 5(a) shows a method of forming the shield layer 200 shown in FIG. 4(a).

First, a base material having the outer circumferential surface 100 is set as a work in an inkjet apparatus (step S1), and the work is cleaned (step S2). In the example of cleaning the work, air blow cleaning using air pressure was used, but adhesive roller cleaning using general organic solvents (alcohols, etc.) or adhesive, plasma cleaning, etc. may also be used.

Next, an inkjet printing pattern of the conductive material 520 is created (step S3). In the inkjet printing pattern creation process, a continuous printing pattern of a conductive layer connected to the ground is created in accordance with the outer peripheral surface 100 of the base material on which the electromagnetic shield is provided.

Then, as described in FIG. 3, the ink 500 containing a conductive material is applied by the inkjet head 400 to the upper surface 102 of the outer peripheral surface 100 of the base material placed on the mounting table 600 (step S4). , the conductive material is thermally cured to form the conductive layer 210 (step S5).

Here, the application of the ink 500 in step S4 is performed using the inkjet printing pattern created in step S3, and in step S5, the volume resistance of the conductive layer is reduced by heating.

In step S5, the base material including the outer circumferential surface 100 may be heated before application, or a heating batch process may be performed after application. In order to obtain stability in the volume and speed of droplets discharged during inkjet application, the viscosity of the ink 500 may be controlled by heating the inkjet head and the ink supply system.

Next, the appearance and film thickness of the conductive layer 210 are inspected for the coating position, film thickness, and other film conditions (step S6).

Then, as explained in FIG. 3, the ink 500 containing an insulating material is applied by the inkjet head 400 to the upper surface 102 of the outer peripheral surface 100 of the base material placed on the mounting table 600 (step S7). , the insulating material is cured by UV exposure (step S8), and the insulating material is thermally cured to form the insulating layer 230 (step S9).

Finally, the appearance and film thickness of the insulating layer 230 are inspected for the coating position, film thickness, and other film conditions (step S10).

Here, if the insulating layer 230 does not require a printed pattern, in step S7, it may be applied using another method such as a dispenser or spray.

When applying an insulating material containing a UV curable resin, by irradiating the ink with UV light immediately after applying it, it is possible to suppress the fluidity of the ink and apply it to a desired position with a desired thickness without waste. When UV light is irradiated, UV light may be irradiated during batch processing after application, or UV light may be irradiated while performing inkjet printing using an inkjet head equipped with a UV lamp or LED.

When the insulating material contains a thermosetting resin, it is heated and cured, making it possible to form an electromagnetic wave shield with superior adhesion, strength, and durability. In the heating step, the base material including the outer circumferential surface 100 may be heated before the ink is applied, or a heating batch process may be performed after the ink is applied.

FIG. 5(b) shows a method of forming the shield layer 200 shown in FIG. 4(b). Steps S11, S12, and S17 to S24 shown in FIG. 5(b) are the same as steps S1 to S10 shown in FIG. 5(a), so a description thereof will be omitted, and steps S13 to S16 will be described below.

After step S12, ink 500 containing an insulating material is applied by the inkjet head 400 onto the surface of the semiconductor package 110 or electronic component 120 placed on the mounting table 600 (step S13), and UV exposure is performed. The insulating material is cured (step S14), and the undercoat layer 150 is formed by thermosetting the insulating material (step S15).

Then, the appearance and film thickness of the undercoat layer 150 are inspected for the coating position, film thickness, and other film conditions (step S16).

If the undercoat layer 150 does not require a printed pattern, the coating may be applied in step S13 using another method such as a dispenser or spray.

When applying an insulating material containing a UV curable resin, by irradiating the ink with UV light immediately after applying it, it is possible to suppress the fluidity of the ink and apply it to a desired position with a desired thickness without waste. When UV light is irradiated, UV light may be irradiated during batch processing after application, or UV light may be irradiated while performing inkjet printing using an inkjet head equipped with a UV lamp or LED. In this embodiment, layers can be formed with high precision by inkjet printing and light irradiation, regardless of the size of the object or surface irregularities. Further, the shield layer including the conductive layer can have a plurality of configurations by partially changing the configuration (arrangement, density, size, etc.).

When the insulating material contains a thermosetting resin, it is heated and cured, making it possible to form an electromagnetic wave shield with superior adhesion, strength, and durability. In the heating step, the semiconductor package 110 or the electronic component 120 may be heated before the ink is applied, or a heating batch process may be performed after the ink is applied.

<Example>
<Conductive layer>
The conductive layer 210 is made of metal nanoparticle ink (_Smart Jet1 manufactured by Genes Inc., SR7000 manufactured by Bando, IJ100E manufactured by FutureInk, I40DM manufactured by Pvnancell, etc.), organic metal ink (TC-IJ-010 manufactured by InkTec, EI-1208 manufactured by Electronick, etc.). It is formed using inkjet printing. Inkjet printing is performed by creating a pattern that is continuously connected in the area direction and has unprinted parts of a minimum size that function as electromagnetic shields.

The length of the unprinted opening in the inkjet printed pattern of the conductive layer 210 is 1 to 2000 um.

If the opening becomes large, it will not be possible to shield high-frequency electromagnetic waves, and if the opening becomes small, the sandwich adhesion effect of the insulating layer will weaken and the durability of the shield layer will decrease due to thermal history. Therefore, the major axis of the opening should preferably be 5. ~1500um, more preferably 10~1000um.

Electromagnetic shields that have mesh shapes for touch panels and display screens and have a conductive layer with an opening area ratio of 40% or more for light transmission are sometimes used. The purpose is to realize a highly durable electromagnetic shield that can shield higher frequency electromagnetic waves by reducing the opening area ratio of the electromagnetic shield.

Forming a conductive layer with a continuous printed pattern, having an arbitrary long axis of openings with an opening area ratio of 1 to less than 50%, more preferably 3 to less than 40%, and providing an insulating layer thereon. This makes it possible to realize a highly durable electromagnetic shielding layer that supports high frequencies.

The inkjet printing pattern of the conductive layer can be of any shape, such as a mesh structure, dither error diffusion, etc., as long as it is connected continuously in the area direction and grounded, and it can achieve the shielding effect and the interaction between the insulating layer and the underlying layer. It is possible to simultaneously increase the adhesive strength by sandwiching.

Regarding shielding properties, a pattern based on dither error diffusion with less periodicity has less shielding leakage at a specific wavelength than a mesh structure with strong periodicity. Depending on the electromagnetic wave frequency and electromagnetic wave intensity to be shielded, different conductive layer printed patterns may be combined within the same electromagnetic wave shield.

Application by inkjet printing is preferable for applying an arbitrary printed conductive layer pattern to an arbitrary location, and more particularly to an uneven area of 5 mm or less.

After inkjet printing, the metal nanoparticle ink and organometallic ink are heated to have a volume resistivity of 10e-3 Ω·cm or less and become a conductive layer that sufficiently reflects electromagnetic waves.

When metal particles are made smaller than 100 nm, the melting point is lower than that of the bulk metal. Therefore, when metal nanoparticle ink is heated, the ink solvent evaporates and the metal nanoparticles are concentrated.Furthermore, due to the lowering of the melting point due to nanoparticle formation, the surfaces of the metal nanoparticles melt and sinter at a temperature lower than that of the bulk metal. However, a conductive bus is formed and the volume resistance is reduced.

Since the metal nanoparticle ink is baked to reflect the concentrated state in which the solvent has evaporated after application, it is desirable to uniformly apply the metal nanoparticle ink in a thin film and allow the solvent to evaporate. For thin and uniform application, an inkjet printing method is better than a spray method, which has a wide distribution of ink particles during application, because it can make the ink particle size uniform.

The heating conditions after inkjet printing are 80 to 180°C and 10 to 60 minutes. When the volume resistance of the conductive layer is further reduced to less than 10e-5, electromagnetic waves are more easily reflected, and the thickness of the conductive layer can be reduced. As the metal nanoparticles, Au, Ag, Cu, etc. can be used, and for the organic metal ink, metal salts such as Ag, Cu, etc. can be used.

If the conductive layer is too thick, it is likely to crack during film formation, and if it is too thin, the shielding performance will be reduced due to the skin effect of electromagnetic wave reflection. Therefore, the thickness of the conductive layer is 0.01 to 20 um, more preferably 0.05 to 20 μm. It is 10um. Making the conductive layer thinner leads to lighter shield layers and resource savings in metal materials.

<Insulating layer and undercoat layer>
Insulating inks for the insulating layer and undercoat layer include PR-1258 (UV curing and thermosetting type) manufactured by Gooh Kagaku, IJSR4000 (UV curing and thermosetting type) manufactured by Taiyo Ink, and PA-1210-35 (UV curing type) manufactured by JNC. Insulating inks of UV curing type and/or heat curing type can be used.

<Insulating layer>
The insulating layer is coated on the patterned conductive layer, and adheres to the base, electronic components, or undercoat layer through the openings of the conductive layer, and adheres in a sandwich-like manner including the conductive layer, resulting in the adhesive strength of the conductive layer being increased. improve.

The insulating layer is formed on the conductive layer by a coating method such as inkjet printing, spraying, or a dispenser. When the openings in the conductive layer are minute, it becomes a problem to fill the openings with an insulating layer, but according to inkjet printing, it is possible to fill the openings with an insulating layer using ink with excellent fluidity. It is easy to do.

The insulating layer preferably has good adhesion to the base or undercoat layer, and is preferably a paint containing a UV-curing or thermosetting resin that has excellent mechanical strength and heat resistance. As a component of the insulating layer, a thermosetting resin is preferable to ensure adhesion with the base and undercoat layer, and a thermosetting epoxy resin is more preferable. It is better to use one that contains hardened resin.

When the insulating layer is composed of both thermosetting and UV curable resin components, UV light irradiation and heating can prevent wetting and spreading and provide adhesive strength with the base and undercoat, increasing the durability of the shield layer. This allows for precise alignment of the shield layer and electronic circuit components.

When the resin contains both curable resins, the curing conditions are UV light irradiation of 100 to 2000 mJ/cm2, heating of 130 to 180°C, and 10 to 60 minutes.

<Undercoat layer>
If the target electronic circuit component has a conductive part that connects to the electronic circuit other than the ground connection part, in order to ensure insulation, an undercoat layer made of an insulating resin is provided, and a conductive layer and an insulating layer are placed on top of that in order. will be established.

The undercoat layer is formed on the electronic circuit component by an application method such as inkjet printing, spraying, or dispensing.

The undercoat layer is required to have adhesive properties with the electronic circuit components, the conductive layer, and the insulating layer, so like the insulating layer, a thermosetting resin is preferable, and a thermosetting epoxy resin is more preferable. To prevent the paint from spreading after application, it is best to use one that contains UV-curable resin.

When the undercoat layer is composed of both thermosetting and UV curing resin components, UV light irradiation and heating can prevent wetting and spreading and provide adhesive strength with the base, conductive layer, and insulating layer. This improves the durability of the shielding layer and enables precise alignment of the shield layer and electronic circuit components.

When the resin contains both curable resins, the curing conditions are UV light irradiation of 100 to 2000 mJ/cm2, heating of 130 to 180°C, and 10 to 60 minutes.

Table 1 shows the base material including the outer circumferential surface 100, the conductive layer, the insulating layer, and the evaluation results in the example and comparative example of the electromagnetic shield shown in FIG. 4(a).

Table 2 shows the base material including the outer circumferential surface 100, the undercoat layer, the conductive layer, the insulating layer, and the evaluation results in the example and comparative example of the electromagnetic shield shown in FIG. 4(b).

Table 3 shows details of substrate types A to E shown in Tables 1 and 2.

Table 4 shows details of the printed patterns A to E of the conductive layer shown in Table 1.

FIG. 6 is a diagram showing print patterns A and B of Table 4 in the electromagnetic shield according to the present embodiment.

The mesh-shaped conductive layer 210 shown in FIG. 6 includes a plurality of connecting parts 214 that connect the plurality of pillar parts 212 shown in FIG. 4, and has a plurality of openings 220 surrounded by the connecting parts 214.

In the conductive layer 210 shown in FIG. 6A, the connecting portion 214 has a width of 580 μm, the opening 220 has a size of 1000 μm×1000 μm, and the opening area ratio is 40%.

In the conductive layer 210 shown in FIG. 6(b), the connecting portion 214 has a width of 125 μm, the opening 220 is formed in a size of 100 μm×100 μm, and the opening area ratio is 20%.

FIG. 7 is a diagram showing the printed pattern C of Table 4 in the electromagnetic shield according to the present embodiment.

A plurality of non-uniformly arranged openings 220 are formed in the dithered conductive layer 210 shown in FIG. 7 . The opening 220 is formed to have a size of 10 μm×10 μm and a major axis of 14 μm, and the opening area ratio is 2.8%.

The dithered conductive layer 210 shown in FIG. 7 is formed in steps S3 and S17 in FIG. It is created as a print pattern combining four pixels 240 at different positions.

FIG. 8 is a diagram showing the printed pattern D of Table 4 in the electromagnetic shield according to this embodiment.

In the dithered conductive layer 210 shown in FIG. 8, a plurality of openings 220 are formed in non-uniform orientations. The opening 220 is formed to have a size of 10 μm×100 μm in length, and has an opening area ratio of 34.7%.

In steps S3 and S17 of FIG. 5, the dithered conductive layer 210 shown in FIG. It is created as a print pattern that combines four pixels 240 with application areas having different orientations.

FIG. 9 is a diagram showing another example of the printed pattern D in Table 4 in the electromagnetic shield according to the present embodiment.

A dithered conductive layer 210 shown in FIG. 9 has a plurality of openings 220 formed in non-uniform orientations. The opening 220 is formed with a major axis of 99 μm, and the opening area ratio is 34.7%.

The dithered conductive layer 210 shown in FIG. 9 is formed in steps S3 and S17 in FIG. 5, with 12×12 dots as one pixel and 50 dots in each pixel 240 as an uninked area. It is created as a print pattern combining four pixels 240 with different orientations.

A plurality of openings 220 having nonuniform sizes and shapes may be formed in the conductive layer 210 by combining the printing patterns A to D in Table 4.

<Evaluation of electromagnetic shielding effect>
FIG. 10 is a diagram showing a method for evaluating the electromagnetic shielding effect according to this embodiment.

As shown in FIG. 10, two shield rooms 310 and 320 are prepared, and test samples 305 produced in Examples and Comparative Examples are placed between them. Here, the conductive layer of test sample 305 is connected to ground.

Further, a transmitting antenna 315 was provided in the first shield room 310 and a receiving antenna 325 was provided in the second shield room 320, and the transmitting antenna 315 and the receiving antenna 325 were connected to a measuring instrument 330. A double ridged guide horn antenna manufactured by EMCO was used as the transmitting antenna 315 and a receiving antenna 325, and a vector network analyzer (37147A) manufactured by Anritsu was used as the measuring instrument 330.

Then, electromagnetic waves were transmitted from the transmitting antenna 315 and measured at frequencies of 1 to 10 GHz, the measurement results were processed by the PC 340, and the electromagnetic wave shielding effect was evaluated from the attenuation rate of the electromagnetic waves.
◎: Indicates an electromagnetic wave attenuation rate of 30 dB or more.
○: Indicates an electromagnetic wave attenuation rate of 20 dB or more and less than 30 dB.
Δ: Indicates an electromagnetic wave attenuation rate of 10 dB or more and less than 20 dB.
×: Indicates an electromagnetic wave attenuation rate of less than 10 dB.

<Evaluation of volume resistivity of conductive layer>
The test samples prepared in Examples and Comparative Examples were measured by a four-terminal method using Loresta GP (manufactured by Mitsubishi Chemical Analytech).

<Heat cycle load application method>
The test samples prepared in Examples and Comparative Examples were subjected to cycles of 10°C⇒100°C and 100°C⇒10°C (1 hour interval for each temperature increase and decrease) 50 times in a constant temperature bath where the temperature could be controlled.

<Evaluation of adhesion (crosscut)>
The test samples prepared in Examples and Comparative Examples were cut with a cutter to form 100 squares of 1 mm square, and Nichiban tape was pasted on them.The tape was peeled off perpendicular to the sample surface, and the remaining squares on the sample were removed. Evaluation was made by the number of pieces.
◎: Indicates that 75 or more squares remained in the sample.
○: Indicates that the number of squares remaining in the sample is 50 or more and less than 75.
Δ: Indicates that the number of squares remaining in the sample is 25 or more and less than 50.
×: Indicates less than 25 squares remaining in the sample

<Production of Examples 1 to 6 and Comparative Examples 1 to 3> (No undercoat layer)
On the 40 mm substrate shown in Table 3, a conductive material was inkjet printed with the printing pattern shown in Table 4 and the film thickness shown in Table 1, and heat treatment was performed to provide a conductive layer. The insulating layer ink shown in Table 1 was applied onto the conductive layer using the film thickness and method (spin coating, inkjet printing) shown in Table 1, and UV curing and/or heat curing was performed under the conditions shown in Table 1. 6. Test samples of Comparative Examples 1 to 3 were prepared.

After applying a heat cycle load to the prepared test sample, adhesiveness (crosscut) was evaluated. Furthermore, using the test samples of Examples and Comparative Examples, the electromagnetic shielding effect was evaluated using the evaluation method shown in FIG. 10, and the results shown in Table 1 were obtained.

Note that the volume resistivity of the conductive layer was measured using a sample prepared separately as follows. A conductive layer was created in the same manner as the above Examples and Comparative Examples, except that the conductive layer was printed on the entire surface without openings instead of pattern printing with openings on the glass substrate, and the volume resistivity was measured using the evaluation method described below. It was measured. The results are also shown in Table 1.

Comparative Examples 1 to 3 all had poor adhesion, and due to the poor adhesion, part of the conductive layer was damaged or peeled off, impairing the function of the conductive layer, resulting in electromagnetic waves. The shield effect is also not good.

<Production of Examples 7 to 10 and Comparative Examples 4 to 7> (With undercoat layer)
On the 40 mm substrate shown in Table 3, the undercoat layer ink shown in Table 2 is applied with the film thickness and method (spin coating, inkjet printing) shown in Table 2, and cured by UV or/and heat under the conditions shown in Table 2. An undercoat layer was prepared. A conductive layer and an insulating layer were formed on the undercoat layer in the same manner as in Example 1 and Comparative Example 1 shown in Table 1 to prepare test samples of Examples 7 to 8 and Comparative Examples 4 to 5.

After applying a heat cycle load to the prepared test sample, adhesiveness (crosscut) was evaluated. Furthermore, using the test samples of Examples and Comparative Examples, the electromagnetic shielding effect was evaluated by the evaluation method described below. The results are shown in Table 2.

Note that the volume resistivity of the conductive layer was measured using a sample prepared separately as follows. A conductive layer was created in the same manner as the above Examples and Comparative Examples, except that the conductive layer was printed on the entire surface without openings instead of pattern printing with openings on the glass substrate, and the volume resistivity was measured using the evaluation method described below. It was measured. The results are also shown in Table 2.

Comparative Examples 4 to 7 all had poor adhesion, and due to the poor adhesion, part of the conductive layer was damaged or peeled off, impairing the function of the conductive layer, resulting in electromagnetic waves. The shield effect is also not good.

●Summary●
[First aspect]
As described above, the method for forming the shield layer 200 according to an embodiment of the present invention includes the steps of forming the conductive layer 210 including the plurality of openings 220 on the upper surface 102 and the side surface 104 of the outer peripheral surface 100 of the base material. , a step of forming an insulating layer 230 that is continuously formed from the surface of the conductive layer 210 to the outer circumferential surface 100 of the base material through the plurality of openings 220 and adhered to the outer circumferential surface 100 of the base material.

Here, the shield layer 200 is an example of an electromagnetic wave shield, the outer peripheral surface 100 of the base material is an example of the surface of the object, and the shield layer is an example of the conductive layer 210.

As a result, the conductive layer 210 is sandwiched between the covering portion 234 and the outer circumferential surface 100 of the base material integrated via the filling portion 232, thereby reducing peeling and cracking on the top surface 102 and side surface 104 of the shield layer 200. be able to.

[Second aspect]
In the first aspect, in the step of forming the conductive layer, inkjet heads 400, 401, 402 discharge ink 500, 501, 502 containing a conductive material onto the upper surface 102 and side surface 104 of the outer peripheral surface 100 of the base material. , a conductive layer 210 including a plurality of openings 220 is formed. Here, the inkjet heads 400, 401, and 402 are examples of application parts, and the inks 500, 501, and 502 are examples of liquid compositions.

[Third aspect]
In the second embodiment, the step of forming the conductive layer includes applying inks 501 and 502 using inkjet heads 401 and 402 in a direction intersecting the upper surface 102 and side surface 104 of the outer circumferential surface 100 of the base material. Thereby, the conductive layer 210 can be reliably formed on the entire both side surfaces 104 of the outer circumferential surface 100 of the base material.

[Fourth aspect]
In any of the first to third aspects, in the step of forming the conductive layer 210, at least one of the size, shape, orientation, and arrangement of the plurality of openings 220 is formed nonuniformly. This reduces shield leakage at specific wavelengths.

[Fifth aspect]
In any of the first to fourth aspects, before the step of forming the conductive layer 210, the method further includes a step of creating a pattern for ejecting the ink 500 by an inkjet. Thereby, the conductive layer 210 can be formed in any pattern.

[Sixth aspect]
Any one of the first to fifth aspects further includes a step of reducing the volume resistivity of the conductive layer 210 by heating the conductive layer 210. Thereby, even if the conductive layer 210 is made into a thin film, the shielding effect of the shield layer 200 can be improved.

[Seventh aspect]
In any of the first to sixth aspects, the step of forming an insulating undercoat layer 150 on the outer peripheral surface 100 of the base material is included, and the step of forming the conductive layer 210 includes a step of forming an electrically conductive layer on the surface of the undercoat layer 150. In the process of forming layer 210 and forming insulating layer 230, insulating layer 230 is continuously formed from the surface of conductive layer 210 to the surface of undercoat layer 150 via a plurality of openings 220.

Thereby, by sandwiching the conductive layer 210 between the covering portion 234 and the surface of the undercoat layer 150 integrated via the filling portion 232, peeling and cracking of the shield layer 200 can be reduced.

[Eighth aspect]
Any one of the first to seventh aspects further includes a curing step of curing at least one of the insulating layer 230 and the undercoat layer 150 by performing at least one of UV irradiation and heating.

Thereby, the adhesive strength between the insulating layer 230 and the outer circumferential surface 100 of the base material can be improved, and peeling and cracking of the shield layer 200 can be further reduced.

[Ninth aspect]
A method of manufacturing a structure including an electronic component 120 according to an embodiment of the present invention includes a method of forming an electromagnetic shield according to any one of the first to eighth aspects.

[Tenth aspect]
In the structure according to an embodiment of the present invention, the shield layer 200 is formed by inkjet on both the upper surface and the side surface of the outer circumferential surface 100 of the base material, and includes a conductive layer 210 including a plurality of openings 220 and a conductive layer 210. An insulating layer 230 that has a covering part 234 and a filling part 232 that is provided continuously with the covering part 234 and fills inside the plurality of openings 220, and is bonded to the outer circumferential surface 100 of the base material at the filling part 232. and.

[Eleventh aspect]
In the tenth embodiment, the base material including the outer circumferential surface 100 is the semiconductor package 110 that houses the electronic component 120 or the electronic component in the electronic device 1.

[Twelfth aspect]
In the tenth aspect or the eleventh aspect, the plurality of openings 220 are formed to be nonuniform in at least one of size, shape, orientation, and arrangement.

[13th aspect]
In any of the tenth to twelfth aspects, the plurality of openings 220 also have a long axis of 10 to 1000 um and an area ratio of 3 to 40%. In this way, inkjet is suitable for forming non-uniform openings 220 and fine openings 220. Furthermore, an inkjet method using ink with excellent fluidity is suitable for filling the inside of the fine opening 220 with the filling portion 232.

[14th aspect]
In any of the eleventh to thirteenth aspects, the base material including the outer peripheral surface 100 is provided with an insulating undercoat layer 150 on the surface, the conductive layer 210 is provided on the surface of the undercoat layer 150, and the insulating layer 210 is provided on the surface of the undercoat layer 150. 230 is bonded to the surface of the undercoat layer 150 at the filling portion.

[15th aspect]
In any of the eleventh to fourteenth aspects, the thickness of the conductive layer 210 is 0.05 to 10 um.

[16th aspect]
In any of the eleventh to fifteenth aspects, the volume resistivity of the conductive layer 210 is 10e-6 to 10e-3 Ω·cm. In this way, inkjet is suitable for forming the thin conductive layer 210.

1 Electronic device 100 Outer peripheral surface 100G Ground section 110 Semiconductor package 120 Electronic component 125 Connection section 130 Substrate 135 Wiring 150 Undercoat layer 200 Shield layer 210 Conductive layer 212 Pillar section 214 Connection section 220 Opening 222 Vertical width 224 Width 230 Insulating layer 232 Filling Section 234 Covering section 240 Pixel region 300 Protective layer 305 Sample 310 First shield room 315 Transmitting antenna 320 Second shield room 325 Receiving antenna 330 Measuring instrument 340 PC
400 Inkjet head (example of application part)
500 ink (an example of liquid composition)
600 Mounting stand

Claims (16)

forming a conductive layer including a plurality of openings on the top and side surfaces of the object;
forming an insulating layer that is continuously formed from the surface of the conductive layer to the surface of the object through the plurality of openings and adhered to the surface of the object;
A method of forming an electromagnetic shield including In the step of forming the conductive layer,
2. The method of forming an electromagnetic shield according to claim 1, wherein a liquid composition containing a conductive material is discharged by a applying section onto the upper and side surfaces of the surface of the object to form a conductive layer including a plurality of openings. The step of forming the conductive layer includes:
3. The method of forming an electromagnetic shield according to claim 2, further comprising applying the liquid composition by the applying unit in a direction intersecting the upper surface and the side surface of the object. 2. The method of forming an electromagnetic shield according to claim 1, wherein in the step of forming the conductive layer, at least one of the size, shape, orientation, and arrangement of the plurality of openings is made non-uniform. 2. The method for forming an electromagnetic shield according to claim 1, further comprising the step of creating a pattern in which the liquid composition is discharged by a applying section before the step of forming the conductive layer. The method for forming an electromagnetic shield according to claim 1, further comprising the step of reducing the volume resistivity of the conductive layer by heating the conductive layer. comprising the step of forming an insulating undercoat layer on the surface of the object,
In the step of forming the conductive layer, the conductive layer is formed on the surface of the undercoat layer,
The method for forming an electromagnetic shield according to claim 1, wherein in the step of forming the insulating layer, the insulating layer is continuously formed from the surface of the conductive layer to the surface of the undercoat layer via the plurality of openings. . A method for forming an electromagnetic shield, further comprising a curing step of curing at least one of the insulating layer according to claim 1 and the undercoat layer according to claim 7 by performing at least one of UV irradiation and heating. A method for manufacturing a structure including an electronic component, comprising the method for forming an electromagnetic shield according to claim 1. a conductive layer formed on both the top and side surfaces of the object and including a plurality of openings;
an insulating layer having a covering part that covers the conductive layer; and a filling part that is provided continuously with the covering part and filling the insides of the plurality of openings, and that is adhered to the surface of the object at the filling part. A structure with and . The structure according to claim 10, wherein the object is an electronic component or a package containing an electronic component. 11. The structure according to claim 10, wherein the plurality of openings are formed to be nonuniform in at least one of size, shape, orientation, and arrangement. The structure according to claim 10, wherein the plurality of openings have a long axis of 10 to 1000 um and an area ratio of 3 to 40%. The object has an insulating undercoat layer on its surface,
The conductive layer is provided on the surface of the undercoat layer,
11. The structure according to claim 10, wherein the insulating layer is adhered to the surface of the undercoat layer at the filling portion. The structure according to claim 10, wherein the conductive layer has a thickness of 0.05 to 10 um. The structure according to claim 10, wherein the conductive layer has a volume resistivity of 10e-6 to 10e-3 Ω·cm.