WO2018143718A1 - Method for forming coating that blocks electromagnetic waves - Google Patents

Abstract

The present invention relates to a method for forming a coating that blocks electromagnetic waves, characterized by comprising: a loading step of attaching a surface of an electronic element to a transfer carrier; a dipping step of dipping the electronic element attached to the transfer carrier into a containing tank in which metal ink is contained such that the metal ink is applied to the exposed outer surface of the electronic element; a sintering step of hardening the metal ink applied to the electronic element; and an unloading step of separating the electronic device from the transfer carrier.

Description

Electromagnetic shielding coating method

The present invention relates to an electromagnetic shielding coating method, and more particularly, to an electromagnetic shielding coating method characterized in that an electromagnetic shielding film is formed on the surface of an electronic device by dipping the surface of the electronic device into a metal ink.

Recently, the rapid development of the electric and electronic industry and information and communication technology has provided a lot of convenience and richness to human life. However, in addition to these advantages, there are various side effects, one of which is the harmfulness of electromagnetic waves generated therefrom. Electromagnetic waves generated from household appliances, information and communication devices, and industrial devices are emerging as new environmental problems due to electromagnetic interference (EMI) and harmful effects on human bodies. In addition, as the speed and speed of electronic and information communication equipments are accelerated, miniaturization, thinning, and weight reduction of not only information communication devices such as mobile phones, notebook computers, personal digital assistants (PDAs), but also daily living products are achieved. As a result, the problem of EMI is more serious, and technology development to solve this problem is urgent.

In general, the semiconductor chip fabricated in the packaging process step of the semiconductor device fabrication process is molded with an insulating resin to protect from the external environment. When the completed electronic device is operated, electromagnetic waves are generated here or vice versa. There is a fear that an error may occur under the influence of the electronic device and cause a serious defect of the electronic device.

As another proposal to solve this problem, there is a method of forming an electromagnetic shielding film on a surface of an electronic device or an outer surface of a resin molding in a dry or wet manner.

As a dry method, a method of forming an electromagnetic shielding film by sputtering is commonly used. In the case of the sputtering method, the sputtering equipment is not only expensive but also has an inefficient disadvantage due to the sputtering being performed for a long time. In addition, due to the nature of the sputtering process, the upper and side surfaces are difficult to form a metal layer with a uniform thickness, so that a mechanical process means for supplementing this situation is required. In order to solve the above problems, a method and apparatus for forming a uniform electromagnetic shielding film on the upper surface and the side in the Republic of Korea Patent Publication KR 10-1686318 B1 (2016.12.07) is disclosed.

The spray method is generally used as a wet method, and is relatively more productive than the sputtering method, but it is not structurally easy to spray on the entire surface of the electronic device, especially the side of the electronic device, and the dust generated during the spraying process There is a problem that causes waste and pollution in the semiconductor clean room. In addition, as in the sputtering process described above, it is difficult to apply a metal layer having a uniform thickness for forming an electromagnetic shielding film on the upper surface and the side in the spraying process.

In addition to the plating method, the plating method has a weak adhesion between the metal layer and the resin, the Republic of Korea Patent Publication No. 10-0839930 (2008.06.20.) Describes a separate pre-treatment process for generating a roughness is disclosed have. However, the plating solution used in the plating process has a disadvantage in that it is difficult to manage and process in terms of environmental safety.

It is most important to form the electromagnetic shielding film only in the necessary shielding area except the mounting surface (PCB surface) of the entire surface of the electronic device, and the problem of forming the metal shielding film in the sputtering method, the spraying method, and the plating method does not require electromagnetic shielding. Occurs. To prevent this, for example, a mounting surface which does not require shielding may be masked by using an adhesive tape. As the metal shielding film is coated on the adhesive tape, a crack occurs in the metal shielding film during unloading of the electronic device. Since there is a problem that the electromagnetic shielding function can not be performed at all, an additional precutting process is required to prevent such defects.

Accordingly, an object of the present invention is to solve such a conventional problem, by dipping the exposed surface of the electronic device in the metal ink to form an electromagnetic shielding film having a uniform thickness on the surface of the electronic device It is about.

According to the present invention, a loading step of attaching one surface of the electronic device to the transport carrier; and dipping the electronic device attached to the transport carrier in a receiving tank containing a metal ink, the exposure of the electronic device A dipping step of applying a metal ink to an outer surface; and a firing step of curing the metal ink applied to the electronic device; And an unloading step of separating the electronic device from the transport carrier.

Here, prior to the dipping step, a surface treatment step for imparting hydrophilicity to the exposed surface of the electronic device attached to the transfer carrier;

In addition, the surface treatment step is preferably a plasma treatment of the surface of the electronic device.

In addition, it is preferable that the electronic device attachment surface of the transfer carrier has hydrophobicity.

In addition, prior to the firing step, a leveling step of making the coating thickness of the metal ink applied to the surface of the electronic device constant; it is preferable to further perform.

In addition, in the leveling step, it is preferable to scrape the metal ink overcoated on the surface of the electronic device with a blade and level the surface flatly.

In addition, in the leveling step, it is preferable that the metal ink overcoated on the surface of the electronic device is absorbed by a blade made of an absorbing material and leveled flatly in the dipping step.

Further, in the dipping step, it is preferable to control the dipping depth of the electronic device according to the specification of the electronic device attached to the transport carrier.

In addition, the receiving tank is preferably to selectively adjust the level of the metal ink to a depth equal to or less than the thickness of the electronic device.

In addition, the transfer carrier is made of a carrier film to be transported in a roll-to-roll manner, it is preferable that one side of the carrier film is provided with an adhesive portion to which one side of the electronic device can be attached.

In addition, in the dipping step, it is preferable to control the dipping depth of the electronic device by pressing the rear surface of the transfer carrier to which the electronic device is attached toward the receiving tank by using a dipping roller which is lifted and controlled at the upper side of the receiving tank.

In addition, in the dipping step, it is preferable to apply the metal ink to the outer surface of the electronic device moving above the dipping roller while the dipping roller absorbing the metal ink of the container rotates.

According to the present invention, by dipping the surface of the electronic device in the metal ink to form an electromagnetic shielding film of uniform thickness on the surface, it is possible to provide an excellent electromagnetic shielding effect in a simplified process.

In addition, in the case of forming the electromagnetic shielding film by the conventional sputtering method, an additional step of removing the electromagnetic shielding film formed in the unnecessary area after sputtering is necessary. In this process, a crack occurs in the electromagnetic shielding film, and thus the original electromagnetic shielding function may be performed due to the crack. Unlike the conventional method, the mounting surface of the electronic device is attached to the bonding part of the transport carrier, and then the exposed surface of the electronic device is dipped into the metal ink to form the electromagnetic shielding film, thereby preventing the electromagnetic shielding film from being formed on the unnecessary part. As a result, it is possible to omit an additional process of removing some of the conventional electromagnetic shielding films, and to prevent the occurrence of cracking of the electromagnetic shielding films.

1 is a process flowchart of the electromagnetic wave shielding coating method according to the first embodiment of the present invention;

Figure 2 is a process step by step of Figure 1,

3 is an enlarged view of the receiving tank shown in FIG.

4 is a process chart showing a modification of the dipping step of the electromagnetic shielding coating method according to the first embodiment of the present invention,

5 is a process chart of the electromagnetic wave shielding coating method according to a second embodiment of the present invention,

6 is a process chart of the electromagnetic wave shielding coating method according to a third embodiment of the present invention.

7 is a comparison table of step coverage characteristics of the coating film according to the electromagnetic shielding forming process.

Hereinafter, an electromagnetic wave shielding coating method according to a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a process flow chart of the electromagnetic wave shielding coating method according to a first embodiment of the present invention, Figure 2 is a process step by step of Figure 1, Figure 3 is an enlarged view of the receiving tank shown in FIG.

As shown in FIG. 1, the electromagnetic wave shielding coating method according to the first embodiment includes a loading step S10, a dipping step S20, a leveling step S30, a baking step S40, and an unloading step S50. Include.

In the present embodiment, for example, it will be described that the transport carrier 10 proceeds for each process while moving in the lateral direction.

In the loading step (S10), as shown in (a) of Figure 2, after mounting the mounting surface (PCB surface) of the electronic device (D) in close contact with the adhesive portion 11 of the transfer carrier 10, the pressure In addition, the electronic device D is attached to the adhesive part 11 of the transfer carrier 10. Meanwhile, a surface treatment step may be performed to impart hydrophilicity to the outer surface of the electronic device D. In this surface treatment step, the surface of the electronic device D may be hydrophilic through surface treatment using plasma P. By providing, the adhesion of the metal ink M can be increased.

In the dipping step S20, as shown in FIGS. 2B and 2C, the transfer carrier 10 is moved to an upper region of the receiving tank 20 in which the metal ink M is accommodated and transferred. In the state where the electronic element D attached to the adhesive part 11 of the carrier 10 faces the container 20 located in the lower area of the carrier carrier 10, the carrier 20 is placed in the container 20. The electronic element D is dipped in the metal ink M by lowering the direction toward the cross section.

Here, the dipping is made only in the essential shielding area of the electronic device (D), the specific example is electromagnetic shielding in the EMC (Epoxy Molding Compound) portion except the mounting surface of the electronic device (D) attached to the bonding portion 11 Since the should be made, as shown in FIG. 2 (b) in the state in which the water level (d2) of the metal ink (M) accumulated in the reservoir 20 is set lower than the side height (d1) of the electronic device (D), Only the top and side portions of (D) can be dipped in the metal ink M to form an electromagnetic shielding film having a uniform thickness.

As described above, it is most important to form the electromagnetic shielding film only in the essential shielding area except the mounting surface of the entire surface of the electronic device D. In the known technologies such as sputtering and spraying, the electronic device (D) that requires shielding is required. The formation of a uniform electromagnetic shielding film on the side of the is not easy, requires a separate masking process for protecting the mounting surface, and must be accompanied by a separate process to prevent cracking of the electromagnetic shielding film during the unloading process.

However, according to the present embodiment, in a state where the mounting surface of the electronic device D is bonded to the bonding portion 11 of the transfer carrier 10, the opposite surface (upper surface) of the mounting surface faces the receiving tank 20. Since the inverting and then dipping, it is possible to apply the metal ink (M) only to the essential shielding area. In particular, the present embodiment prevents the metal ink M from being applied to the mounting surface because the mounting surface of the electronic device D, which is a problem in the prior art, is not exposed because it is bonded to the bonding portion 11 of the transfer carrier 10. In addition, since the metal ink (M) is applied to the side of the electronic device (D) at once, it is possible to provide an integrated electromagnetic shielding film of uniform thickness. Therefore, since the electromagnetic wave shielding film is not formed in an unnecessary area as in the prior art, an additional process for removing the electromagnetic wave is unnecessary, and the crack of the electromagnetic wave protection layer that may occur in such a removal process is not caused, and the seal of the electronic device D The scene can be prevented from being contaminated by the metal for forming the electromagnetic shielding film.

Meanwhile, as shown in FIG. 3, the reservoir 20 must maintain the level of the metal ink M required for dipping the electronic device D, and thus, the water level adjusting means is provided inside the reservoir 20. It is preferable that it is provided. More specifically, the water level (d2) of the metal ink (M) accumulated in the receiving tank 20 should be equal to or lower than the side height (d1) of the electronic device (D), depending on the size of the electronic device (D) It is preferable to comprise so that the water level of (M) can be adjusted. In addition, in order to precisely adjust the level of the metal ink (M) of the receiving tank 20, by installing the water level sensor 21 to replenish the metal ink (M) in a constant amount as much as the amount of the metal ink (M) constant water level It is preferable to maintain the, and the water level sensor 21 used may be a laser type, ultrasonic type, magnetostrictive, frequency type, floating type sensor. On the other hand, in addition to such a sensor, it is also possible to use a variety of sensors that can measure the level of the metal ink (M) in the receiving tank (20).

In order to precisely control the uniformity of the electromagnetic wave shielding film in addition to adjusting the water level of the receiving tank 20, at least one of the height adjusting device of the electronic device D and the height adjusting device of the receiving tank 20 may be used. It is preferable to provide.

In addition, as the supply means 22 for supplying the metal ink M, a diaphragm pump, a tube pump, a piston pump, and a gear pump can be used, and in addition, various kinds capable of quantitatively discharging the metal ink M can be used. It is also possible to use a pump. When the metal ink M stored in the tank 20 overflows, the water level sensor 21 senses the level of the metal ink M, thereby separating the gap between the tank 20 and the electronic device D. The excess metal ink M may be drained by adjusting or by adjusting the height of the sidewall of the container 20 to be lower than the side height of the electronic device D. At this time, the drained excess metal ink (M) may be stored in the storage tank 23 and supplied to the receiving tank 20 through the supply means 22 again.

As the metal ink (M) used in the dipping step (S20), any metal ink (M) containing a conductive metal can be used, for example, a metal ink (M) containing conductive metal particles, a metal ink of a particleless type (M) All are applicable, but not limited to.

In addition, as the metal ink (M), a conductive metal can be used in various ways. For example, a silver ink containing silver (Ag) can be used, and in the case of silver, a metal that can provide excellent electromagnetic shielding effect among metals. Therefore, it may be preferable to use silver ink, but is not necessarily limited to silver ink. In addition to these mixtures, solvents, stabilizers, dispersants, binder resins, crosslinkers, reducing agents, surfactants, wetting agents, thixotropic agents or leveling agents, thickeners, as necessary And additives such as antifoaming agents.

It is preferable that it is 1-50,000 cPs, and, as for the viscosity of the metal ink (M) composition of this invention, it is more preferable that it is 5-400 cPs. If the viscosity value is too low, the flowability increases, making it difficult to form a uniform electromagnetic shielding film on the upper and side surfaces of the electronic device D. If the viscosity value is too high, the flowability decreases excessively, resulting in uneven thickness of the electromagnetic shielding film and plasticity. Due to the poor electrical conductivity, adhesion characteristics and appearance problems occur.

In addition, the surface tension of the metal ink (M) may be adjusted to obtain a uniform electromagnetic shielding film on the upper and side surfaces and the bent portion of the electronic device (D). It is preferable that the surface tension of the metal ink M is 35 dyn / cm at maximum, and it is more preferable that it is 30 dyn / cm or less. When the surface tension of the metal ink (M) is high, the ink is concentrated on the upper and side surfaces due to the wettability of the metal ink (M) with respect to the surface of the electronic device (D), and the application of the ink is thinned on the bent portion, thereby revealing the bent portion after firing. Defects can occur. Such defects can be eliminated by repeating the dipping step S20 several times, but it is natural that the number of dipping steps S20 should be minimized in terms of production efficiency.

 In addition, in order to express the shielding property of the electromagnetic shielding film, the electrical property of the electromagnetic shielding film formed of the metal ink M of the present embodiment is preferably at most 800 mW / square or less. When the electrical conductivity is low, since the thickness of the electromagnetic shielding film is thickened to secure the required electromagnetic shielding properties, it may adversely affect the light and thin shortening of the electronic device (D).

When sufficient dipping is completed, as shown in FIG. 2C, the electronic device D is moved upwardly from the container 20, and the electronic device D is removed from the metal ink M of the container 20. Will be withdrawn.

Through the dipping step S20, the metal ink M may be applied to a portion of the upper surface and the side surface of the entire surface of the electronic device D, which require electromagnetic shielding. On the other hand, after setting the level of the metal ink (M) accommodated in the receiving tank 20 according to the height required for electromagnetic shielding, and dipping and withdrawing the electronic element (D) to the bottom surface of the receiving tank 20, electromagnetic shielding There is an advantage in that the electromagnetic wave shielding film can be constantly formed only up to the side height of the required electronic device (D).

In the leveling step (S30), as shown in (d) of Figure 2, in order to prevent the phenomenon of the metal ink (M) applied to the surface of the electronic device (D), excessive amount accumulated on the surface of the electronic device (D) Removing the metal ink (M) can be performed to planarize. For example, when the blade 30 made of a material having a predetermined hardness is disposed at a position spaced apart from the upper surface of the electronic device D by a predetermined distance, the blade 30 and the electronic device D are relatively moved. The blade 30 may scrape and planarize the metal ink M overcoated on the electronic device D. FIG. In addition, by absorbing a predetermined amount of the metal ink (M) over-coated on the surface of the electronic device (D) by using a blade 30 made of an absorbent material, such as a porous material, it is possible to prevent the metal ink (M) from falling out. As the absorbent material such as porous material, for example, sponge, EVA foam, urethane foam can be used, and in addition, various porous absorbent materials can be used.

In the firing step (S40), the metal element (M) is applied to the surface of the electronic element (D), the electronic element (D) is heated to perform firing.

This firing step (S40) may include a primary firing step and a secondary firing step, the primary firing is preliminary firing, the conditions may vary depending on the type of the electronic device (D) or the use environment, As shown in (d) and (e) of FIG. 2, preheating at 80 ° C. for 1 minute while providing thermal energy to the electronic device D coated with the metal ink M through the primary heater 41. You can proceed. The primary purpose of the first firing step is to minimize or eliminate the fluidity of the metal ink M uniformly coated on the surface of the electronic device D to maintain uniformity until the second firing step is reached. In addition, in the secondary firing step, firing may be performed at 150 ° C. for 5 minutes through the secondary heater 42, but is not limited thereto.

The unloading step (S50), as shown in (f) of Figure 2, is to separate the electronic device (D) from the bonding portion 11 of the transport carrier 10, the separated electronic device (D) The electromagnetic shielding film is formed by applying and firing the metal ink M only on the upper surface and a part of the side surface.

On the other hand, the adhesive portion 11 used in this embodiment is to maintain the adhesive force while the dipping step (S20) proceeds, but it is good to lose the adhesive force or have a weak adhesive force before going to the unloading step (S50). Contamination of the mounting surface of the electronic device (D) in the unloading step (S50) causes a product defect, so it is natural that there should be no transition of the adhesive material from the adhesive portion 11 at all. In order to lose the adhesive force of the electronic device (D), an ultraviolet (UV) curing tape may be used, or more preferably, a foam tape may be used, and a tape capable of selectively losing the adhesive force may be used. On the other hand, after attaching the electronic device (D) to the tape to form an electromagnetic shielding film with a metal ink (M), if the adhesive portion 11 that maintains a level of adhesion without difficulty in separating from the adhesive portion 11, dipping step The adhesive force may not change before and after (S20).

Meanwhile, as shown in FIG. 4, the water level d2 of the metal ink M that accumulates in the receiving tank 20 is set to be equal to the side height d1 of the electronic device D, so that the electronic device D has a side surface. In the case of dipping by the thickness of, it is preferable to selectively hydrophobize the surface of the adhesive portion 11. As described above, when the characteristic difference between the surface of the hydrophilic treated electronic device D and the surface of the hydrophobic treated adhesive part 11 is used, the metal ink M is formed between the mounting part of the electronic device D and the adhesive part 11. It is possible to form an electromagnetic wave shielding film in an infiltrated state. In order to impart hydrophobicity, the adhesive part 11 may include a hydrophobic material such as Teflon or silicon, or may be surface treated using the hydrophobic material, and may also use a micrometer having a nanometer size.

As described above, according to the present embodiment, the surface of the electronic device D may be dipped in the metal ink M to form an electromagnetic shielding film on the top and side surfaces of the electronic device D. Can be provided.

A separate protective coating layer may be formed on the electromagnetic shielding film for the purpose of protecting the electromagnetic shielding film formed as needed from the external environment. As the protective coating layer, it is preferable to use a polymer resin composition such as thermosetting resin or UV curing resin. In the semiconductor inspection process, not only color may be added for the purpose of increasing recognition rate or appearance quality, but also silver is used as the metal material of the electromagnetic shielding film, mercaptan in the protective coating layer composition. It may include a compound, a carboxylic acid compound or a silane compound. As a method of forming the above-described protective coating layer, it is preferable to use a process of coating and curing using a dipping process similarly to the metal ink (M) described above.

Thus, according to this embodiment, by dipping the surface of the electronic device (D) in the metal ink (M) to form an electromagnetic shielding film and a protective coating layer on the surface of the electronic device (D), excellent electromagnetic shielding in a simplified process Can provide an effect.

Next, a description will be given of the electromagnetic shielding coating method according to a second embodiment of the present invention with reference to the accompanying drawings.

5 is a process chart of the electromagnetic wave shielding coating method according to a second embodiment of the present invention.

As shown in FIG. 5, the electromagnetic wave shielding coating method according to the second embodiment may be indirectly dipped using a dipping roller 24 having a porous moisture absorption structure unlike the first embodiment.

In addition, the transport carrier 10 is formed of a carrier film wound in the form of a roll provided with an adhesive portion on one surface, in the process of transferring in a roll-to-roll method, a loading step (S10), a dipping step (S20) ), The firing step (S40) and the unloading step (S50) is performed in sequence, which is advantageous for the continuous process.

Specifically, in the loading step (S10) and after the mounting surface of the electronic device (D) in close contact with the transfer carrier 10, it is attached by applying pressure.

The electronic device D attached to the transport carrier 10 through the loading step S10 moves on the roll-to-roll line and moves to the dipping step S20. In the dipping step S20, the electronic device D moves to the transport carrier 10. The attached electronic device D comes into contact with the dipping roller 24. At this time, the dipping roller 24 has a porous moisture absorption structure and is dipped in advance in the metal ink M of the receiving tank 20 so as to contain sufficient metal ink M, and the upper region of the receiving tank 20. Application of the metal ink (M) to the upper and side surfaces of the electronic device (D) requiring electromagnetic shielding by rotating the dipping roller 24 can be made at the same time. In this case, the material of the dipping roller 24 is urethane foam, silicon foam, rubber foam is preferably used, in addition to the metal ink (M) is easy to transfer, the metal ink (M) on the upper and side surfaces of the electronic device (D) Of course, it is possible to use a material having a modulus of elasticity necessary to coat it. In addition, the interval between the dipping roller 24 and the electronic device (D) can be adjusted according to the specifications of the electronic device (D), for this purpose, in the upper region of the dipping roller 24 of the transport carrier 10 The roller supporting the back surface can be configured to be adjustable up and down.

The electronic device D, which has been coated with the metal ink M, is subjected to a firing step S40, which is a next step, through a roll-to-roll line. In the firing step (S40), preliminary firing and final firing may be performed through the primary heater 41 and the secondary heater 42, and when the metal ink M is completely cured by the firing step S40, An electromagnetic shielding film is formed on the top and side surfaces of the device D, and is then separated from the transport carrier 10 through an unloading step (S50).

On the other hand, in the case of indirect dipping using the dipping roller 24 as in the second embodiment, the coating amount of the metal ink M applied to the surface of the electronic device D through the absorption rate of the dipping roller 24 is determined. Since it can be controlled, the leveling step in the first embodiment for removing a part of the metal ink M overcoated on the surface of the electronic device D may be omitted.

Next, an electromagnetic wave shielding coating method according to a third embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 6, the electromagnetic wave shielding coating method according to the third embodiment includes a roll-to-roll process differently from the first embodiment.

To this end, the transport carrier 10 is made of a carrier film wound in the form of a roll provided with an adhesive portion on one surface, in the process of transporting in a roll-to-roll manner, a loading step (S10), surface treatment step, dipping step (S20), Since the leveling step (S30), the firing step (S40) and the unloading step (S50) are performed in sequence, it is advantageous for the continuous process.

As shown in Figure 6, the electronic device (D) attached to the transport carrier 10 through the loading step (S10) is moved to the dipping step (S20) while moving in a roll-to-roll line, dipping step (S20) ), The back surface of the transfer carrier 10 to which the electronic device D is attached is pressed by the pressure roller 25, and dipped into the metal ink M of the receiving tank 20.

At this time, since the angle of entry (angle roll) disposed on both sides of the pressure roller 25 can be adjusted to the entry angle of the electronic device (D) enters the receiving tank 20, the coating on the electronic device (D) during the dipping process It is possible to maximize the uniformity of the metal ink (M). Here, when the entrance angle of the electronic device (D) is too large than the horizontal, when the electronic device (D) enters the first side of the receiving tank 20 and the side of the later touching portion may not be constant coating height If the entry angle is too low, only a portion of the side surface of the electronic device D may be coated, and thus, it may be difficult to form an electromagnetic shielding film of a required portion.

Thereafter, the electronic device D transferred in a roll-to-roll manner is withdrawn from the metal ink M of the storage tank 20 while leaving the section pressurized toward the storage tank 20 by the pressure roller 25. . At this time, since the receiving tank 20 is to maintain a certain amount of water level as described above, it is preferable that the receiving tank 20 is provided with a level control means such as the water level sensor 21. In addition, by further comprising a vibration means for providing ultrasonic vibration to the receiving tank 20 to improve the dipping efficiency, by placing the uneven at the bottom of the receiving tank 20 to control the fluidity of the metal ink (M) coating It is possible to improve the characteristics. That is, when the fluidity of the metal ink (M) is high and uniform coating is difficult, in addition to adjusting the viscosity of the metal ink (M), by adjusting the flow resistance of the metal ink (M) due to the unevenness of the prepared reservoir 20 It can lead to a uniform coating.

Through the dipping step (S20), the application of the metal ink (M) is completed on the upper and side surfaces of the entire surface of the electronic device (D), the electromagnetic wave shielding to the outside is required.

In the continuous process according to the roll-to-roll transfer method, the electronic device D is withdrawn from the receiving tank 20, moves through the roll-to-roll line, and enters the leveling step S30.

In this leveling step (S30), in order to prevent chipping of the metal ink M applied to the surface of the electronic device D in a continuous process in which the electronic device D moves a roll-to-roll line, the surface of the electronic device D The metal ink (M) over-coated in the blade 30 is scraped with a leveling (leveling) operation to flatten it flat.

Here, for example, it is described as leveling by using a blade 30 in the form of rods spaced apart from the electronic device D at predetermined intervals. However, the overcoated metal ink M may be partially removed and planarized. It is also possible to use other means, and as another example, the blade 30 may be made of a porous absorbent material, thereby preventing the ink bleeding phenomenon by absorbing a certain amount of the metal ink M collected on the surface of the electronic device D. .

When the leveling step (S30) is completed, the firing step (S40) of the next step through the roll-to-roll line. In the firing step (S40), preliminary firing and final firing may be performed through the primary heater 41 and the secondary heater 42, and the metal ink coated on the electronic device D by the firing step S40 ( When M) is completely cured, an electromagnetic shielding film is formed on the upper and side surfaces of the electronic device D, and then the electronic device D on which the electromagnetic shielding film is formed is separated from the transport carrier 10 through an unloading step S50. do.

As described above, according to the present invention, the surface of the electronic device D is dipped in the metal ink M to form an electromagnetic shielding film, thereby providing an excellent electromagnetic shielding effect in a simplified process.

Hereinafter, the configuration and effects of the present invention through the embodiments will be described in more detail. These examples are only for illustrating the present invention, but the scope of the present invention is not limited by these examples.

<Measurement of properties>

The sheet resistance of the ink coating surface was measured using a sheet resistance meter (4 point probe), the viscosity was measured at 20 rpm, 25 ℃ using a Brookfield viscometer with 0.5 ml of ink, the surface tension of K20 (Easy dyne KRUSS) Was measured.

Dispersion particle size was measured by diluting 10% ink in butyl carbitol solvent using dynamic light scattering.

Coating thickness was measured using FE-SEM, electromagnetic shielding test was measured by the electromagnetic shielding performance (S21 Parameter, ASTM D4935).

<Production of Electromagnetic Shielding Coating Ink>

 Preparation Example 1 Preparation of Ag Particles in a Particle-Free Form

Ag 2-ethylhexylcarbamate 100g, solvent (Butanol 100g, Isobutylamine 50g), dispersant (BYK 145145, 1g), binder resin (epoxy resin, 0.5g), wetting agent (antittera 204, 0.2g), leveling agent (EFKA 350 , 0.05 g) was mixed to prepare a particleless Ag ink having a viscosity of 5 cps, surface tension of 23 dyne / cm, and sheet resistance of 650 mPa / □.

Preparation Example 2 Preparation of Metal Particles in Particle-Free Form

100 g Ag 2-ethylhexylcarbamate and solvent (Anisole 20g, 2-ethylhexyl amine 40g), dispersant (BYK 145, 0.5g), binder resin (epoxy resin, 0.3g), wetting agent (antittera 204, 0.2g), leveling (EFKA 350, 0.05 g) was mixed to prepare a particleless Ag ink having a viscosity of 38 cps, surface tension of 29 dyne / cm, and sheet resistance of 300 mPa / □.

Preparation Example 3 Preparation of Nanoparticle Dispersed Metal Ink

40 g Ag nanoparticles, a solvent (butyl carbitol 60 g), a dispersant (BYK 145, 4 g), a stabilizer (Ethyl cellulose, 2 g), a binder resin (Cellulose acetate butyrate, 1 g) were mixed in a 500 ml reactor, and 0.3 mm beads were used. 6 h mixed and reacted uniformly.

After the reaction was completed, the beads were removed by a filter to obtain an ink in which Ag nanoparticles were uniformly dispersed. An ink having a viscosity of 50 cps, a surface tension of 26 dyne / cm, and a sheet resistance of 90 mPa / □ was prepared.

Preparation Example 4 Preparation of Nanoparticle Dispersed Metal Ink

40g Ag nanoparticles, solvent (Propylene glycol monomethyl ether acetate, 50g), dispersant (BYK 330, 5g), stabilizer (Ethyl cellulose, 2g), binder resin (Polyvinyl butyral, 1g) were mixed in 500ml reactor, 0.3mm beads 6 h was mixed and reacted uniformly. After the reaction was completed, the beads were removed with a filter to obtain an ink in which Ag nanoparticles were uniformly dispersed. An ink having a viscosity of 400 cps, a surface tension of 35 dyne / cm, and a sheet resistance of 50 mΩ / □ was prepared.

Preparation Example 5 Preparation of Paste Type Metal Ink

Ag powder (40g), binder resin (epoxy resin, 10g), adhesion promoter (BYK 4510, 0.3g), thixotropic agent (Fumed silica, 0.05g), solvent (butyl carbitol, 0.5g) was mixed, 3- The paste ink having a viscosity of 50,000 cps and a sheet resistance of 60 mPa / s was prepared by mixing and preparing with a roll mill.

Electromagnetic shielding coating process

Example 1

By using the viscosity of 5cps particleless metal ink of [Preparation Example 1], the other 5 surfaces except the lower surface of the six surfaces of the semiconductor package were coated through the vertical dipping process of the first embodiment and then fired at 150 ° C. for 5 minutes. To form an electromagnetic shielding film.

The sheet resistance of the shielding film thus formed is 700mΩ / □, step coverage 93%, shielding rate 32dB

Example 2

By using the viscosity of 38 cps particle-free metal ink of [Preparation Example 2], the other five surfaces of the six surfaces of the semiconductor package except the lower surface of the semiconductor package were coated by the vertical dipping process of the first embodiment, followed by preliminary firing at 80 ° C. for 1 min. And 150 ° C., 5 min final firing to form an electromagnetic shielding film. The sheet resistance of the shielding film thus formed is 350mΩ / □, step coverage 95%, shielding rate 42dB.

Example 3

Using the viscosity of 50cps nanoparticle dispersed metal ink of [Preparation Example 3], after coating five remaining surfaces except for the lower surface of the six surfaces of the semiconductor package through the vertical dipping process of the first embodiment for 130 ℃, 10 minutes It bakes and forms an electromagnetic wave shielding film.

The sheet resistance of the thus formed shielding film is 100mΩ / □, step coverage 94%, shielding rate 50dB.

Example 4

The viscosity of [Production Example 4] 400cps Ag nanoparticle dispersion type metal ink was coated, the other five surfaces except the lower surface of the six surfaces of the semiconductor package through the vertical dipping process of the first embodiment 130 ℃, 15min It fires during the time and forms an electromagnetic wave shielding film.

The sheet resistance of the thus formed shielding film is 55mΩ / □, step coverage 95%, shielding rate 61dB.

Example 5

Using the Ag paste-type metal ink having a viscosity of 50,000 cps of [Production Example 5], the other five surfaces except the lower surface of the six surfaces of the semiconductor package were coated through a vertical dipping process of the first embodiment, followed by 130 ° C. and 20 min. It fires during the time and forms an electromagnetic wave shielding film.

The sheet resistance of the shielding film thus formed is 65mΩ / □, step coverage 95%, shielding rate 57dB.

Example 6

By using the viscosity of 5cps particleless metal ink of [Preparation Example 1], the other five surfaces of the six surfaces of the semiconductor package except for the lower surface of the semiconductor package were coated through the indirect dipping process of the second embodiment, followed by preliminary firing at 80 ° C. for 1 min. And 150 ° C., 5 min final firing to form an electromagnetic shielding film.

The sheet resistance of the shielding film thus formed is 750mΩ / □, step coverage 90%, shielding rate 30dB.

Example 7

By using the viscosity 38cps particleless metal ink of [Preparation Example 2], the other five surfaces of the six surfaces of the semiconductor package except the lower surface of the semiconductor package were coated through the indirect dipping process of the second embodiment, and then fired at 150 ° C. for 5 minutes. Through the electromagnetic shielding film is formed.

The sheet resistance of the thus formed shielding film is 400mΩ / □, step coverage 92%, shielding rate 40dB.

Example 8

The viscosity of 50cps nanoparticle dispersed metal ink of [Preparation Example 3] was coated on the other five surfaces except for the lower surface of the six surfaces of the semiconductor package through the indirect dipping process of the second embodiment, followed by 130 ° C. for 10 minutes. Firing forms an electromagnetic shielding film.

The sheet resistance of the shielding film thus formed is 150mΩ / □, step coverage 91%, shielding rate 48dB.

Example 9

Viscosity of [Production Example 4] 400cps Ag nanoparticle dispersion type metal ink, after coating the remaining five surfaces except the lower surface of the six surfaces of the semiconductor package through the indirect dipping process of the second embodiment 130 ℃, 15min During the firing, an electromagnetic wave shielding film is formed.

The sheet resistance of the thus formed shielding film is 57mΩ / □, step coverage 93%, shielding rate 61dB.

Example 10

Using Ag paste-type metal ink having a viscosity of 50,000 cps of [Production Example 5], the other five surfaces of the six surfaces of the semiconductor package except the bottom surface of the semiconductor package were coated through the indirect dipping process of the second embodiment, followed by 130 ° C. and 20 min. During the firing, an electromagnetic wave shielding film is formed.

The sheet resistance of the shielding film thus formed is 70 mΩ / □, step coverage 92%, shielding rate 56dB.

Example 11

By using the viscosity of 5cps particleless metal ink of [Preparation Example 1], the other five surfaces except the lower surface of the six surfaces of the semiconductor package were coated by the Roll to Roll dipping process of the third embodiment, followed by 150 ° C for 5 minutes. During the firing, an electromagnetic wave shielding film is formed. The sheet resistance of the shielding film thus formed is 650mΩ / □, step coverage 95%, shielding rate 34dB.

Example 12

By using the viscosity of 38cps particleless metal ink of [Preparation Example 2], the remaining five surfaces of the six surfaces of the semiconductor package except the lower surface of the semiconductor package were coated through the Roll to Roll dipping process of the third embodiment at 80 ° C. for 1 min. Electromagnetic shielding film is formed by preliminary firing and final firing at 150 ° C. for 5 min. The sheet resistance of the shielding film thus formed is 300 mΩ / □, step coverage 96%, shielding rate 43dB.

Example 13

By using the viscosity of 50cps nanoparticle dispersed metal ink of [Preparation Example 3], the other five surfaces except the lower surface of the six surfaces of the semiconductor package through the Roll to Roll dipping process of the third embodiment 130 ℃, Firing for 10 min to form an electromagnetic shielding film.

The sheet resistance of the thus formed shielding film is 90mΩ / □, step coverage 97%, shielding rate 52dB.

Example 14

The viscosity of 400 cps Ag nanoparticle-dispersion type metal ink of [Production Example 4] was coated at 130 ° C. after the other five surfaces of the six surfaces of the semiconductor package were coated by the roll to roll dipping process of the third embodiment. , The electromagnetic shielding film is formed by firing for 15 minutes.

The sheet resistance of the shielding film thus formed is 50 mPa / □, step coverage 96%, shielding rate 65dB.

Example 15

The Ag paste-type metal ink having a viscosity of 50,000 cps of [Production Example 5] was coated at 130 ° C. after coating the remaining five surfaces of the six surfaces of the semiconductor package through the Roll to Roll dipping process of the third embodiment. 20 minutes to form an electromagnetic shielding film through firing.

The sheet resistance of the shielding film thus formed is 60m Ω / □, step coverage 96%, shielding rate 59dB.

Electromagnetic shielding film protective coating

Example 19

The remaining layer of the six surfaces of the semiconductor package except the lower surface of the six surfaces of the semiconductor package was coated with a thermosetting resin through a roll to roll dipping process of the third embodiment on the electromagnetic shielding film prepared in Example, and then fired for 180 ° C. for 10 min. To form a protective coating layer through.

Example 20

After coating the remaining five of the six surfaces of the semiconductor package except the lower surface of the six surfaces of the semiconductor package with the UV curable resin through the Roll to Roll dipping process of the third embodiment on the electromagnetic shielding film prepared in the [Example] To form.

Comparative Example of Electromagnetic Shielding Coating Process

Comparative Example 1 / sputtering process

Sputtering apparatus A metal sintered compact was formed as a sputtering target using the DC magnetron sputter apparatus. Film-forming conditions were room temperature, DC500W, 6% oxygen concentration, and annealing conditions were performed at 300 degreeC x 1 hr in air | atmosphere atmosphere. The target module was sputtered on the upper and side surfaces by adjusting the sputtering angle so as to coat the remaining five surfaces except for the surface provided with solder balls, thereby forming a shield film having a SUS / CU / SUS multilayer structure.

The step coverage of the shielding film thus formed is 41%.

[Comparative Example 2] / spray process

Using spray equipment (787MS-SS valve), spray coating the ink on the upper side and the side of the viscosity of 50cps nanoparticle dispersion ink of [Production Example 3], and then firing at 130 ° C. for 10 min. A shielding film is formed. The step coverage of the shielding film thus formed is 47%.

<Physical measurement result>

The characteristics of the prepared electromagnetic shielding ink are shown in Table 1 below.

Ink type	Particle-free Ag ink		Nanoparticle Disperse Ag Ink		Paste Ink
Production Example	Preparation Example 1	Preparation Example 2	Preparation Example 3	Preparation Example 4	Preparation Example 5
Viscosity (cps)	5	38	50	400	50,000
Surface tension (dyne / cm)	23	29	26	35	-
Sheet resistance (mΩ / □)	650	300	90	50	60

Table 2 summarizes the characteristics of the electromagnetic shielding film formed according to the electromagnetic shielding dipping process prepared in Example.

Electromagnetic Shielding Film Properties by Dipping Process and Ink Type

First Embodiment Vertical Dipping	Example 1 / Production Example 1	Example 2 / Production Example 2	Example 3 / Production Example 3	Example 4 / Production Example 4	Example 5 / Production Example 5
Sheet resistance (mΩ / □)	700	350	100	55	65
Step coverage (%)	93	95	94	95	95
Shielding Rate (dB)	32	42	50	61	57
Second Embodiment Indirect Dipping	Example 6 / Production Example 1	Example 7 / Production Example 2	Example 8 Preparation Example 3	Example 9 / Production Example 4	Example 10 Preparation Example 5
Sheet resistance (mΩ / □)	750	400	150	57	70
Step coverage (%)	90	92	91	93	92
Shielding Rate (dB)	30	40	48	61	56
Roll to Roll dippings	Example 11 / Production Example 1	Example 12 / Production Example 2	Example 13 / Production Example 3	Example 14 / Production Example 4	Example 15 Production Example 5
Sheet resistance (mΩ / □)	650	300	90	50	60
step coverage (%)	95	96	97	96	96
Shielding Rate (dB)	34	43	52	65	59

Comparison of Step Coverage Characteristics of Coating Films by Electromagnetic Shielding Formation Process

		Example 13	Comparative Example 1	Comparative Example 2
fair		Roll to RollDipping	Sputter	Spray
Coating thickness (um)	Top	1.8	4.1	3.15
	side	1.75	1.7	1.5
step coverage (%)		97	41	47

The scope of the present invention is not limited to the above-described embodiment, but may be embodied in various forms of embodiments within the scope of the appended claims. Without departing from the gist of the invention claimed in the claims, it is intended that any person skilled in the art to which the present invention pertains falls within the scope of the claims described in the present invention to various extents which can be modified.

Claims (12)

1. A loading step of attaching one surface of the electronic device to the transport carrier;

   Dipping the electronic element attached to the transfer carrier in a container containing a metal ink to apply the metal ink to the exposed outer surface of the electronic element;

   Firing the metal ink applied to the electronic device; And

   And an unloading step of separating the electronic device from the transport carrier.
2. The method of claim 1,

   Prior to the dipping step, the surface treatment step of imparting hydrophilicity to the exposed surface of the electronic device; electromagnetic shielding coating method further comprising.
3. The method of claim 2,

   The surface treatment step of the electromagnetic shielding coating method characterized in that the plasma treatment of the surface of the electronic device.
4. The method of claim 2,

   Electromagnetic shielding coating method characterized in that the electronic device attachment surface of the transfer carrier has a hydrophobicity.
5. The method of claim 1,

   Prior to the firing step, a leveling step of making the coating thickness of the metal ink applied to the surface of the electronic element constant; electromagnetic shielding coating method further comprising.
6. The method of claim 5,

   Wherein the leveling step, the electromagnetic shielding coating method characterized in that the leveling (leveling) by scraping the metal ink over-coated on the surface of the electronic device with a blade in a dipping step.
7. The method of claim 5,

   Wherein the leveling step, the electromagnetic shielding coating method characterized in that the leveling (leveling) by absorbing the metal ink over-coated on the surface of the electronic device with a blade made of the absorbing material in the dipping step.
8. The method of claim 1,

   The dipping step, the electromagnetic shielding coating method characterized in that for controlling the dipping depth of the electronic device, according to the specification of the electronic device attached to the transport carrier.
9. The method of claim 8,

   The receiving tank is electromagnetic shielding coating method characterized in that for adjusting the level of the metal ink to the same or lower depth of the thickness of the electronic device.
10. The method of claim 1,

    The transfer carrier is made of a carrier film to be transported in a roll-to-roll manner, the electromagnetic shielding coating method, characterized in that the one side of the carrier film is provided with an adhesive portion to which one side of the electronic device can be attached.
11. The method of claim 10,

    The dipping step, the electromagnetic shielding coating method characterized in that to control the dipping depth of the electronic device by pressing the back surface of the transfer carrier to which the electronic device is attached to the receiving tank using a dipping roller which is lifted and controlled at the upper side of the receiving tank.
12. The method of claim 10,

    The dipping step, the electromagnetic shielding coating method characterized in that the metal ink is applied to the outer surface of the electronic element moving in the upper side of the dipping roller while the dipping roller absorbing the metal ink of the receiving tank.

Images