TW201829839A - Electromagnetic wave shield coating method - 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

Coating method for electromagnetic wave shielding

The present invention relates to a coating method for electromagnetic wave shielding, and more particularly, to a coating method for electromagnetic wave shielding, which is characterized in that, by dipping the surface of an electronic component into metallic ink, the electronic component An electromagnetic wave shielding film is formed on the surface.

Recently, the rapid development of the electrical and electronic industry and information and communication technologies have provided many conveniences and nourishment to human life. However, in addition to these advantages, there are various side effects, one of which is the harmfulness of the resulting electromagnetic waves. The electromagnetic waves generated from household electrical appliances, information communication equipment, and industrial equipment, together with the electromagnetic interference (EMI) between the devices, are harmful to the human body, and therefore cause new environmental problems. In addition, with the acceleration of electronic and information communication equipment and the acceleration of broadband, information communication equipment such as mobile phones, notebook computers, personal digital assistants (PDAs), and daily necessities have been miniaturized, Thinning and lightening have caused the EMI problem to be more serious, so it can be said that there is an urgent need for technology development to solve this problem.

Generally speaking, in the packaging process in the semiconductor device process, the fabricated semiconductor wafer is molded with an insulating resin to protect it in an external environment. The finished electronic components will generate electromagnetic waves during operation, or in turn be affected by the electromagnetic waves generated by the surroundings to produce errors, which may cause serious defects in electronic equipment.

As another solution for solving this problem, there is a method of forming an electron wave shielding film on the surface of an electronic component or on the outer surface of a resin molding through dry or wet methods.

The dry method generally adopts a method of forming an electromagnetic wave shielding film through a sputtering method. In the sputtering method, the sputtering equipment is not only quite expensive, but also takes a long time to perform sputtering, so it has a problem of low efficiency. Moreover, in terms of the characteristics of the sputtering process, it has the disadvantage that it is difficult to form a metal layer with a uniform thickness on the top and sides, so it is necessary to further increase the mechanical process device to compensate for the disadvantages. In order to solve the problems described above, a method and apparatus for uniformly forming an electromagnetic wave shielding film on the top and sides are disclosed in Korean Patent Publication KR10-1686318B1 (December 7, 2016).

The spray method is more common in the wet method. Although it is superior to the sputtering method in terms of production efficiency, it has the following problems: because of its structural characteristics, it is not easy to affect the entire surface of the electronic component, especially the side of the electronic component. The spraying is carried out, and the dust generated during the spraying process causes waste of ink materials and pollution in the semiconductor purification room. In addition, as with the aforementioned sputtering process, it is difficult to apply a uniform thickness metal layer for forming an electromagnetic wave shielding film on the upper and side surfaces during the spraying process.

In addition, there is a plating method, but in the plating method, since the adhesion between the metal layer and the resin is weak, Korean Patent Gazette No. 10-0839930 (June 20, 2008) discloses a method for Description of the additional pretreatment process that produces roughness. However, the plating solution used in the plating process has the disadvantage of requiring special management and handling in terms of environmental safety.

The most important thing is that the electromagnetic wave shielding film is formed only on the necessary shielding area except the mounting surface (PCB surface) on the entire surface of the electronic component. The sputtering method, spraying method and plating method all produce a metal shielding film formation Problems in areas where electromagnetic waves are not required. To prevent this problem, for example, tape can be used to mask the mounting surface that does not need to be masked. However, as the metal masking film is also applied to the tape, when unloading electronic components, the metal masking film will have cracks, which cannot be used at all. The electromagnetic wave shielding function is performed. Therefore, in order to prevent such defects, a further precutting process is required.

Patent Document 0001: KR10-1686318B1 (December 7, 2016).

Patent document 0002: KR10-0839930B1 (June 20, 2008).

Therefore, the present invention is proposed to solve the above-mentioned conventional problems, and its object is to provide a coating method for electromagnetic wave shielding by dipping the exposed surface of an electronic component in a metallic ink, thereby An electromagnetic wave shielding film with a uniform thickness can be formed on the surface of the electronic component.

The object is achieved by the electromagnetic wave shielding coating method of the present invention. The method includes: a loading step, attaching one side of the electronic component to the transport carrier; and a dipping step, dipping the electronic component attached to the transport carrier ) In the containing tank containing the metal ink, the metal ink is coated on the exposed outer surface of the electronic component; the firing step solidifies the metal ink coated on the electronic component; and the unloading step, from the conveyance The electronic component is separated from the carrier.

Here, preferably, prior to the impregnation step, a surface treatment step of imparting hydrophilicity to the exposed surface of the electronic component attached to the carrier is further performed.

In addition, it is preferable to perform plasma treatment on the surface of the electronic component in this surface treatment step.

In addition, preferably, the electronic component attachment surface of the carrier has hydrophobicity.

In addition, preferably, before the firing step, a leveling step of leveling the coating thickness of the metal ink applied on the surface of the electronic component is further performed.

In addition, preferably in this leveling step, the metal ink excessively coated on the surface of the electronic component in the dipping step is scraped off with a blade, so that the leveling is flat.

In addition, preferably in this leveling step, a blade composed of an absorbing material is used to absorb the metal ink excessively coated on the surface of the electronic component in the dipping step, thereby leveling into a flat shape.

In addition, preferably in this immersion step, the immersion depth of the electronic components is controlled according to the specifications of the electronic components attached to the transport carrier.

In addition, it is preferable that the receiving tank adjusts the water level of the metal ink to a depth that is the same as or lower than the thickness of the electronic component.

In addition, it is preferable that the conveyance carrier is composed of a carrier film conveyed in a roll-to-roll manner, and an adhesive part is provided on one side of the carrier film, and one side of the electronic component can be attached to the adhesive part.

In addition, preferably, in this immersion step, an immersion roller that is controlled to move up and down on the upper side of the storage tank is used to pressurize the opposite side of the surface of the transport carrier to which the electronic component is attached to the storage tank to control the immersion depth of the electronic component.

In addition, preferably, in the immersion step, the immersion roller that absorbs the metallic ink in the storage tank rotates, and at the same time, the outer surface of the electronic component that moves on the upper side of the immersion roller is coated with the metallic ink.

By immersing the surface of the electronic component in the metal ink, the invention forms an electromagnetic wave shielding film with a uniform thickness on the surface of the electronic component. Therefore, it can provide an excellent electromagnetic wave shielding effect through a simplified process.

In addition, when the electromagnetic wave shielding film is formed by the conventional sputtering method, an additional process of removing the electromagnetic wave shielding film formed in the necessary area must be performed after sputtering. During this process, cracks may occur on the electromagnetic wave shielding film. Cracked and unable to perform the original electromagnetic wave shielding function. Unlike this conventional method, the present invention forms an electromagnetic wave shielding film by immersing the exposed surface of the electronic component in the metallic ink after attaching the mounting surface of the electronic component to the sticking portion of the carrier, and thus can prevent the above portion from being necessary By forming the electromagnetic wave shielding film, it is possible to omit the conventional additional process for removing part of the electromagnetic wave shielding film, and it is possible to prevent the occurrence of cracks in the electromagnetic wave shielding film.

Next, the electromagnetic wave shielding coating method of the first embodiment of the present invention will be described in detail with reference to the drawings.

1 is a process sequence diagram of an electromagnetic wave shielding coating method according to a first embodiment of the present invention, FIG. 2 is a process diagram shown in steps of FIG. 1, and FIG. 3 is an enlarged view of the receiving tank shown in FIG. 2.

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

In this embodiment, a description will be given by taking each process while carrying the carrier 10 laterally as an example.

In this loading step S10, as shown in FIG. 2(a), after the mounting surface (PCB surface) of the electronic component D is closely attached to the sticking portion 11 of the carrier 10, pressure is applied to attach the electronic component D to the carrier 10 on the pasting part 11. In addition, a surface treatment step for imparting hydrophilicity to the outer surface of the electronic component D may be performed. In this surface treatment step, the surface treatment of the electronic component D may be imparted with hydrophilicity by surface treatment using plasma P, thereby enabling Increase the adhesion of metallic ink M.

In this immersion step S20, as shown in (b) and (c) of FIG. 2, the transport carrier 10 is moved to the upper region of the storage tank 20 where the metal ink M is stored, and the sticking portion 11 attached to the transport carrier 10 is made With the electronic component D on the upper side facing the storage tank 20 located in the lower region of the transport carrier 10, the transport carrier 10 is lowered toward the storage tank 20 to immerse the electronic component D in the metal ink M.

The feature here is that the immersion is performed only on the necessary shielding area of the electronic component D. As a specific example, it is necessary to perform electromagnetic waves on the EMC (Epoxy Molding Compound) part other than the mounting surface of the electronic component D attached to the sticking portion 11 As shown in (b) of FIG. 2, only the upper surface of the electronic component D can be set in a state where the water level d2 of the metal ink M accumulated in the storage tank 20 is set lower than the side height d1 of the electronic component D The side surfaces are immersed in the metallic ink M to form a uniform thickness electromagnetic wave shielding film.

As mentioned above, the most important thing is to form an electromagnetic wave shielding film only on the entire shielding area of the entire surface of the electronic component D except for the mounting surface. It is not easy to use known techniques such as sputtering or spraying on the side of the electronic component D that needs to be shielded A uniform electromagnetic wave shielding film is formed thereon, and an additional masking process for protecting the mounting surface is required, and an additional process for preventing cracking of the electromagnetic wave shielding film is required during the unloading process.

However, in this embodiment, when the mounting surface of the electronic component D is in close contact with the attaching portion 11 of the carrier 10, it is reversed to the opposite surface (upper surface) of the mounting surface toward the storage tank 20 for immersion, so it can only be The metal ink M is coated on the necessary masking area. Especially in this embodiment, the mounting surface of the electronic component D, which has been a problem in the prior art, is pasted on the pasting portion 11 of the transport carrier 10 without being exposed, so it is possible to prevent the application of the metallic ink M on the mounting surface and the electronic The side surface of the element D is coated with the metal ink M at the same time, so it is possible to provide an integrated electromagnetic wave shielding film of uniform thickness. Therefore, the electromagnetic wave shielding film is not formed on the necessary area as in the past, so an additional process for removing the electromagnetic wave shielding film formed on the necessary area is not required, and there is no possibility of incurring such a removal process. The crack of the electromagnetic wave protective layer can prevent the mounting surface of the electronic component D from being contaminated by the metal used to form the electromagnetic wave shielding film.

In addition, as shown in FIG. 3, the storage tank 20 should maintain the water level of the metal ink M required for the immersion of the electronic component D. Therefore, a water level adjustment device is preferably provided inside the storage tank 20. In more detail, the preferred structure is that the water level d2 of the metal ink M accumulated in the storage tank 20 should be the same as or lower than the side height d1 of the electronic component D, and the metal ink M can be adjusted according to the specifications of the electronic component D Water level. In addition, in order to accurately adjust the water level of the metal ink M in the storage tank 20, it is preferable to provide a water level sensor 21 to replenish the metal ink M according to the amount of the metal ink M prescribed so as to maintain the predetermined water level as the used water level The sensor 21 can use a laser method, an ultrasonic method, a magnetostrictive (magnetic distortion) method, a frequency method, and a floating sensor. In addition to such sensors, various types of sensors capable of detecting the level of the metallic ink M in the storage tank 20 may be used.

In order to more accurately control the uniformity of the electromagnetic wave shielding film together with the adjustment of the water level of the storage tank 20, at least one of the height adjustment device of the electronic component D and the height adjustment device of the storage tank 20 is preferably provided during the immersion.

In addition, as the supply device 22 for supplying the metallic ink M, a diaphragm pump, a tube pump, a piston pump, and a gear pump may be used. In addition, various types of pumps capable of quantitatively discharging the metallic ink M may be used. When the metal ink M stored in the storage tank 20 overflows, the water level of the metal ink M can be sensed through the water level sensor 21, and the interval between the storage tank 20 and the electronic component D can be adjusted, or the storage tank The height of the side wall of 20 is adjusted to be lower than the height of the side of the electronic component D, so that excessive metal ink M is discharged. The excessive metal ink M discharged at this time can be stored in the storage tank 23 and then supplied to the storage tank 20 through the supply device 22.

As the metal ink M used in the immersion step S20, any metal ink M containing conductive metal can be used. For example, the metal ink M containing conductive metal particles and the particle-free type metal ink M can be used. Not limited to this.

In addition, as the metal ink M, as long as it is a conductive metal, it can be applied in various ways. As an example, a silver ink containing silver (Ag) may be used. Among metals, silver is a metal that can provide an excellent electromagnetic wave shielding effect, so silver ink is preferably used, but it is not necessarily limited to this. In addition to its mixture, it may include solvents, stabilizers, dispersants, binder resins, crosslinking agents, reducing agents, surfactants, wetting agents, thixotropy as needed Thixotropic agent or additives such as leveling agent, thickener and defoamer.

The viscosity of the metallic ink M composition of the present invention is preferably 1 to 50000 cPs, and more preferably 5 to 400 cPs. When the viscosity value is too low, it is difficult to form a uniform electromagnetic wave shielding film on the top and sides of the electronic component D due to increased fluidity. When the viscosity value is too high, the thickness of the electromagnetic wave shielding film is uneven due to too little fluidity, which cannot be achieved sufficiently. Sintering will cause problems in electrical conductivity, adhesion characteristics and appearance.

In addition, in order to obtain a uniform electromagnetic wave shielding film on the top and sides of the electronic component D and on the curved portion, the surface tension of the metal ink M can be adjusted. The maximum value of the surface tension of the metallic ink M is preferably 35 dyn/cm, and more preferably 30 dyn/cm or less. When the surface tension of the metal ink M is high, due to the wettability of the metal ink M to the surface of the electronic component D, the ink will concentrate on the upper and side surfaces, and the thinner coating on the curved portion may result after firing Defects exposed at the bend. Such defects can be eliminated by repeating the impregnation step S20, but of course, the number of impregnation steps S20 should be reduced as far as possible in terms of production efficiency.

Furthermore, in order to reflect the shielding characteristics of the electromagnetic wave shielding film, the maximum value of the electrical characteristics of the electromagnetic wave shielding film formed of the metallic ink M of the present embodiment is preferably 800Ω/cm 2. When the electrical conductivity is low, the thickness of the electromagnetic wave shielding film becomes thicker in order to ensure the required electromagnetic wave shielding characteristics, which may be unfavorable for the thinning and shortening of the electronic component D.

After sufficient immersion is completed, as shown in FIG. 2( c ), the electronic component D is moved upward from the storage tank 20, and the electronic component D is taken out of the metallic ink M in the storage tank 20.

Through this dipping step S20, the metallic ink M can be applied to the upper and side surfaces of the portion of the entire surface of the electronic component D that requires electromagnetic wave shielding. In addition, when the water level of the metallic ink M contained in the storage tank 20 is set according to the height required for electromagnetic wave shielding, when the electronic component D is immersed in the bottom surface of the storage tank 20 and then taken out, there is always only The advantage of forming the electromagnetic wave shielding film uniformly up to the side height of the element D.

In this leveling step S30, as shown in FIG. 2(d), in order to prevent the concentration phenomenon of the metal ink M coated on the surface of the electronic component D, the excessive metal ink M concentrated on the surface of the electronic component D may be removed And flatten the job. As an example, when the blade 30 made of a material with a predetermined hardness is disposed at a predetermined distance from the upper surface of the electronic component D, when the blade 30 and the electronic component D are relatively moved, the blade 30 can scrape off the excessive coating. The metal ink M on the electronic component D is planarized. In addition, the blade 30 composed of an absorbent material such as a porous material may also absorb a certain amount of metal ink M applied to the electronic component D in excess to prevent the concentration of the metal ink M. As an absorbent material such as a porous material, for example, sponge, EVA foam, and polyurethane foam can be used. In addition, various porous absorbent materials can be used.

In this firing step S40, in a state where the metal ink M is coated on the surface of the electronic component D, the electronic component D is heated and fired.

The firing step S40 may include a primary firing step and a secondary firing step. The primary firing step becomes pre-firing, and the conditions may vary according to the type of electronic component D or the use environment, but as shown in (d) and ( As shown in e), the electronic element D coated with the metallic ink M can be supplied with thermal energy through the primary heating machine 41 while pre-firing at 80° C. for one minute. The main purpose of the primary firing step is to maintain uniformity before the secondary firing step by minimizing or removing the fluidity of the metallic ink M evenly coated on the surface of the electronic component D. In addition, in the secondary firing step, firing may be performed at 150° C. for five minutes through the secondary heater 42, but it is not limited to such firing conditions.

This unloading step S50 is for separating the electronic component D from the sticking portion 11 of the transport carrier 10 as shown in (f) of FIG. 2. In the separated electronic component D, a permeable metal is formed only on a part of the upper surface and side surfaces Electromagnetic wave shielding film for coating and firing of ink M.

In addition, the adhesive part 11 used in this embodiment preferably maintains the adhesion while performing the immersion step S20, and loses the adhesive force or has a weak adhesive force before entering the unloading step S50. In the unloading step S50, the contamination of the mounting surface of the electronic component D causes product defects, so of course there must be no transfer of the sticking substance from the sticking portion 11. In order to lose the adhesive force of the electronic component D, an ultraviolet (UV) curing tape may be used, or more preferably a foam tape, or an adhesive tape that can selectively lose the adhesive force. In addition, after the electronic component D is attached to the tape and the electromagnetic wave shielding film is formed through the metal ink M, as long as the adhesive portion 11 maintains no difficulty in adhesion during separation from the adhesive portion 11, even before and after the immersion step S20 It doesn't matter if the sticking force is the same.

In addition, as shown in FIG. 4, when the water level d2 of the metal ink M accumulated in the storage tank 20 is set to be the same as the height d1 of the side surface of the electronic component D, and is immersed according to the thickness of the side surface of the electronic component D, it is preferable to The surface of the sticking portion 11 is selectively subjected to hydrophobic treatment. As described above, if the characteristics of the surface of the electronic component D after the hydrophilic treatment and the surface of the adhesive portion 11 after the hydrophobic treatment are different, no metal ink can penetrate between the mounting portion of the electronic component D and the adhesive portion 11 In the state of M, an electromagnetic wave shielding film is formed. In order to impart hydrophobicity, the adhesive portion 11 may contain hydrophobic materials such as polytetrafluoroethylene or silicone, or use these materials for surface treatment, or may use fine protrusions of nanometer size.

In this way, according to the present embodiment, the electromagnetic wave shielding film can be formed on the upper and side surfaces of the electronic component D by immersing the surface of the electronic component D in the metal ink M, and therefore, it is possible to provide an excellent electromagnetic wave shielding effect through a simplified process.

If necessary, in order to protect the electromagnetic wave shielding film formed from the outside, a protective coating may be formed on the electromagnetic wave shielding film. The protective coating is preferably composed of a polymer resin such as thermosetting resin or UV curing resin. In order to improve the recognition rate or improve the appearance quality in the semiconductor inspection process, the color can be further increased, and when silver (Ag) is used as the metal material of the electromagnetic wave shielding film, sulfur can be included in the composition of the protective coating Alcohol (mercaptan) compounds or carboxylic acid compounds or silane compounds. The formation method of the above protective coating is the same as that of the aforementioned metal ink M, and it is preferable to adopt a process of coating and curing using a dipping process.

Therefore, according to the present embodiment, an electromagnetic wave shielding film is formed on the surface of the electronic component D by immersing the surface of the electronic component D in the metal ink M, and a protective coating is formed as necessary, so that an excellent electromagnetic wave can be provided through a simplified process Masking effect.

Next, referring to the drawings, an electromagnetic wave shielding coating method according to a second embodiment of the present invention will be described.

5 is a manufacturing process diagram of an 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 of the second embodiment is different from that of the first embodiment, and the impregnation roller 24 having a porous absorption structure is used for indirect impregnation.

In addition, the transport carrier 10 is provided with an adhesive portion on one surface, and is composed of a roll-shaped curled carrier film. During the roll-to-roll transportation, the loading step S10 and the dipping step S20 are sequentially performed The firing step S40 and the unloading step S50 are therefore beneficial to the continuous process.

Specifically, in the loading step S10, the mounting surface of the electronic component D is closely adhered to the conveyance carrier 10, and pressure is applied thereto to adhere.

The electronic component D attached to the transport carrier 10 through the loading step S10 moves on a roll-to-roll line, and moves to the dipping step S20. In the dipping step S20, the electronic component D attached to the transport carrier 10 is in contact with the dipping roller 24. At this time, the immersion roller 24 is composed of a porous absorption structure, and is in a state of being previously immersed in the metal ink M of the storage tank 20 to contain sufficient metal ink M, and can penetrate the immersion roller rotating in the upper region of the storage tank 20 24. The metal ink M is simultaneously coated on the upper and side surfaces of the electronic component D requiring electromagnetic wave shielding. At this time, the material of the impregnating roller 24 is preferably polyurethane foam, silicone foam or foam rubber, but other than that, of course, it is possible to easily transfer the metal ink M and have metal coated on the top and sides of the electronic component D The material of the elasticity coefficient required in the ink M. In addition, the interval between the impregnating roller 24 and the electronic component D can be adjusted according to the specifications of the electronic component D. For this reason, the roller supporting the opposite side of the transport carrier 10 in the upper region of the impregnating roller 24 can be configured to be capable of up and down positions Adjust.

After the electronic component D coated with the metal ink M passes through the roller-to-roller line, the next step is the firing step S40. In the firing step S40, the primary heater 41 and the secondary heater 42 can be used for pre-firing and final firing. If the metal ink M is completely cured through this firing step S40, the An electromagnetic wave shielding film is formed on the side, and then the electronic component D is separated from the carrier 10 through the unloading step S50.

In addition, when the impregnation roller 24 is used for indirect impregnation as in the second embodiment, the application amount of the metal ink M applied on the surface of the electronic component D can be controlled through the absorption rate of the impregnation roller 24, so the first embodiment can be omitted The leveling step in is used to remove a portion of the metal ink M excessively coated on the surface of the electronic component D.

Next, referring to the drawings, the electromagnetic wave shielding coating method of the third embodiment of the present invention will be described in detail.

As shown in FIG. 6, the electromagnetic wave shielding coating method of the third embodiment is different from the first embodiment, and is composed of a roll-to-roll process.

To this end, the transport carrier 10 is provided with an adhesive portion on one side, and is composed of a roll-shaped curled carrier film. During the roller-to-roll transport, the loading step S10, the surface treatment step, and the dipping step S20 are sequentially performed. The leveling step S30, the firing step S40, and the unloading step S50 are therefore beneficial to the continuous process.

As shown in FIG. 6, the electronic component D attached to the transport carrier 10 through the loading step S10 moves on the roll-to-roll line, and moves to the immersion step S20. In the immersing step S20, the opposite surface of the transport carrier 10 to which the electronic component D is attached is pressed by the pressing roller 25, so as to be immersed in the metallic ink M of the storage tank 20.

At this time, the angle of the electronic rollers D into the accommodating tank 20 can be adjusted by an angle roll disposed on both sides of the pressure roller 25, so that the metallic ink applied to the electronic components D during the dipping process can be made The uniformity of M is maximized. Here, when the entry angle of the electronic component D is too large than the level, it is possible that the coating height of the side surface of the portion that first contacts the bottom of the receiving groove 20 and the contact portion after the entry of the electronic component D is inconsistent. When it is small, only a part of the side of the electronic component D can be coated, so that it may be difficult to form a necessary part of the electromagnetic wave shielding film.

After that, the electronic component D conveyed by the roller-to-roller method is separated from the section that is pressed toward the storage tank 20 by the pressure roller 25 and is taken out of the metallic ink M from the storage tank 20. At this time, as described above, the storage tank 20 should maintain a predetermined amount of water level. Therefore, a water level adjustment device such as a water level sensor 21 is preferably provided in the storage tank 20. In addition, a vibration device for providing ultrasonic vibration can be further provided in the containing tank 20, so that the impregnation efficiency can also be improved, and the fluidity of the metal ink M can be controlled by arranging irregularities on the bottom of the containing tank 20 to improve the coating OVER CHARACTERISTICS. That is, when the fluidity of the metallic ink M is high and it is difficult to achieve uniform coating, in addition to adjusting the viscosity of the metallic ink M, the flow resistance of the metallic ink M can be adjusted through the unevenness of the prepared storage tank 20 to guide Even coating.

Through such an immersion step S20, the metallic ink M is coated on the upper and side surfaces of the entire surface of the electronic component D that are exposed to the outside and require electromagnetic wave shielding.

The electronic component D is taken out from the storage tank 20 through the continuous process of the roller-to-roller conveyance method, and then the electronic component D moves through the roller-to-roller line and then proceeds to the leveling step S30.

In this leveling step S30, in order to prevent the concentration of the metallic ink M coated on the surface of the electronic component D in a continuous process in which the electronic component D moves on the roll-to-roll line, a leveling operation is performed, which leveling In the operation, the metal ink M excessively applied on the surface of the electronic component D is scraped off by the blade 30 to make it flat.

Here, the flattening using the rod blade 30 spaced apart from the electronic component D by a predetermined interval has been described as an example, but it may also be flattened by removing part of the excessively applied metal ink M In another device, as another example, the blade 30 is composed of a porous absorbent material, and by absorbing a predetermined amount of the metallic ink M concentrated on the surface of the electronic component D, the concentration of ink can be prevented.

After completing the leveling step S30, the next step through the roller-to-roller line is the firing step S40. In the firing step S40, pre-firing and final firing can be performed through the primary heater 41 and the secondary heater 42, and if the metal ink M is completely cured through this firing step S40, it is on the electronic component D The electromagnetic wave shielding film is formed on the side surface, and then the electronic component D formed with the electromagnetic wave shielding film is separated from the transport carrier 10 through the unloading step S50.

In this way, according to the present invention, the surface of the electronic component D is immersed in metal ink to form an electromagnetic wave shielding film. Therefore, an excellent electromagnetic wave shielding effect can be provided through a simplified process.

Hereinafter, the structure and effect of the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and the scope of the present invention is not limited to these examples. Physical property testing

The surface resistance of the ink-coated surface was tested using a surface resistance detector (4 Point Probe); for the viscosity, 0.5 ml of ink was taken and tested at 20 rpm and 25°C using a Brinell viscometer ; The surface tension was tested with KRUSS K20 (Easy dyne).

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

The coating thickness was tested by FE-SEM; for the electromagnetic shielding test, the electromagnetic shielding performance instrument (S21 Parameter, ASTM D4935) was used for testing. Preparation of electromagnetic wave shielding coating ink

Preparation Example 1: Preparation of particle-free silver ink

By mixing silver 2-ethylhexyl carbamate (100g) and solvent (butanol 100g, isobutylamine 50g), dispersant (BYK 145145, 1g), binder resin (epoxy resin, 0.5g), Wetting agent (antittera 204, 0.2g) and leveling agent (EFKA 350, 0.05g) prepared particle-free silver ink with viscosity 5cps, surface tension 23dyne/cm and surface resistance 650mΩ/cm ² .

Preparation Example 2: Preparation of particle-free metal ink

By mixing 100g of silver 2-ethylhexyl carbamate and a solvent (anisole 20g, 2-ethylhexylamine 40g), dispersant (BYK 145, 0.5g), binder resin (epoxy resin, 0.3g ), wetting agent (antittera 204, 0.2g) and leveling agent (EFKA 350, 0.05g), a particle-free silver ink with a viscosity of 38cps, a surface tension of 29dyne/cm and a surface resistance of 300mΩ/cm ² was prepared.

Preparation Example 3: Preparation of Nano Particle Dispersed Metallic Ink

For silver nanoparticles 40g and solvent (butyl carbitol, 60g), dispersant (BYK 145, 4g), stabilizer (ethyl cellulose, 2g) and binder resin (cellulose acetate butyrate, 1g) ) Mixing was carried out in a 500ml reactor, and 0.3mm beads (Beeds) were used to uniformly mix and react for six hours.

After the reaction was completed, the beads were removed through a screening program to obtain an ink with silver nanoparticles uniformly dispersed, and an ink with a viscosity of 50 cps, a surface tension of 26 dyne/cm, and a surface resistance of 90 mΩ/cm ² was prepared.

Preparation Example 4: Preparation of Nano Particle Dispersed Metal Ink

For silver nanoparticles (40g) and solvent (propylene glycol methyl ether acetate, 50g), dispersant (BYK 330, 5g), stabilizer (ethyl cellulose, 2g) and binder resin (polyvinyl alcohol) Butyraldehyde, 1 g) was mixed in a 500 ml reactor and mixed and reacted uniformly for 6 hours using 0.3 mm beads. After the reaction was completed, the beads were removed through a screening program to obtain an ink with silver nanoparticles uniformly dispersed, and an ink with a viscosity of 400 cps, a surface tension of 35 dyne/cm, and a surface resistance of 50 mΩ/cm ² was prepared.

Preparation Example 5: Preparation of Paste Metallic Ink

For silver powder (40g), binder resin (epoxy resin, 10g), adhesion promoter (BYK 4510, 0.3g), thixotropic agent (smoke silicone, 0.05g) and solvent (butyl carbitol, 0.5 g) After mixing, use a three-roll mill to mix to prepare paste ink with viscosity 50000cps and surface resistance 60mΩ/cm ² . Electromagnetic wave shielding coating process example 1

Using the particle-free metal ink with a viscosity of 5 cps in Preparation Example 1, through the vertical dipping process of the first embodiment, the five surfaces of the six sides of the semiconductor package except for the bottom surface are coated, and then at 150 ℃ 5 Firing in minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 700 mΩ/cm ² , the step coverage was 93%, and the shielding rate was 32 dB. Example 2

Using the particle-free metal ink with a viscosity of 38 cps of Preparation Example 2, through the vertical dipping process of the first embodiment, the five surfaces of the six sides of the semiconductor package except the bottom surface are coated, and then at 80 ℃ 1 Pre-firing for 5 minutes and final firing at 150°C for 5 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 350 mΩ/cm ² , the step coverage was 95%, and the shielding ratio was 42 dB. Example 3

Using the nanoparticle-dispersed metal ink with a viscosity of 50 cps in Preparation Example 3, the vertical dipping process of the first embodiment was used to coat five of the six surfaces of the semiconductor package except the bottom surface, and then at 130° C. The firing was performed for 10 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 100 mΩ/cm ² , the step coverage was 94%, and the shielding rate was 50 dB. Example 4

Using the silver nanoparticle dispersion type metal ink with a viscosity of 400 cps of Preparation Example 4, through the vertical dipping process of the first example, the five surfaces of the semiconductor package except the bottom surface are coated on the six surfaces, and then at 130°C The firing was performed for 15 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 55 mΩ/cm ² , the step coverage was 95%, and the shielding rate was 61 dB. Example 5

Using the silver paste-like metallic ink with the viscosity of 50000cps of Preparation Example 5, through the vertical dipping process of the first embodiment, the six surfaces of the semiconductor package except for the bottom surface are coated, and then at 130 ℃ 20 Firing in minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 65 mΩ/cm ² , the step coverage was 95%, and the shielding rate was 57 dB. Example 6

Using the particle-free metal ink with a viscosity of 5 cps in Preparation Example 1, through the indirect dipping process of the second embodiment, the five surfaces of the six sides of the semiconductor package except the bottom surface are coated, and then at 80 ℃ 1 It is pre-fired for 5 minutes and finally fired at 150°C for 5 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 750 mΩ/cm ² , the step coverage was 90%, and the shielding rate was 30 dB. Example 7

Using the particle-free metal ink with a viscosity of 38 cps in Preparation Example 2, through the indirect dipping process of the second example, the five surfaces of the six sides of the semiconductor package except the bottom surface are coated, and then at 150 ℃ 5 Firing in minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 400 mΩ/cm ² , the step coverage was 92%, and the shielding rate was 40 dB. Example 8

Using the nanoparticle-dispersed metal ink with a viscosity of 50 cps in Preparation Example 3, through the indirect immersion process of the second example, five of the six surfaces of the semiconductor package except the bottom surface are coated, and then at 130° C. The firing was performed for 10 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 150 mΩ/cm ² , the step coverage was 91%, and the shielding rate was 48 dB. Example 9

Using the silver nanoparticle-dispersed metal ink with a viscosity of 400 cps in Preparation Example 4, through the indirect dipping process of the second example, five of the six surfaces of the semiconductor package except the bottom surface were coated, and then at 130°C The firing was performed for 15 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 57 mΩ/cm ² , the step coverage was 93%, and the shielding rate was 61 dB. Example 10

Using the silver paste-like metallic ink with the viscosity of 50000cps of Preparation Example 5, through the indirect dipping process of the second embodiment, the six surfaces of the semiconductor package except the bottom surface are coated on the five surfaces, and then at 130 ℃ 20 Firing in minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 70 mΩ/cm ² , the step coverage was 92%, and the shielding rate was 56 dB. Example 11

Using the particle-free metal ink with a viscosity of 5 cps in Preparation Example 1, through the roll-to-roll dipping process of the third example, five surfaces of the six sides of the semiconductor package except the bottom surface are coated, and then at 150° C. The firing was performed for 5 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 650 mΩ/cm ² , the step coverage was 95%, and the shielding rate was 34 dB. Example 12

Using the particle-free metal ink with a viscosity of 38 cps of Preparation Example 2, through the roll-to-roll dipping process of the third example, the five surfaces of the six sides of the semiconductor package except the bottom surface are coated, and then at 80° C. The preliminary firing was performed for 1 minute, and the final firing was performed at 150°C for 5 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 300 mΩ/cm ² , the step coverage was 96%, and the shielding rate was 43 dB. Example 13

Using the nanoparticle-dispersed metal ink with a viscosity of 50 cps in Preparation Example 3, through the roll-to-roll dipping process of the third example, five of the six faces of the semiconductor package except the bottom face are coated, and then coated at 130 The sintering is performed at 10° C. for 10 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 90 mΩ/cm ² , the step coverage was 97%, and the shielding rate was 52 dB. Example 14

Using the silver nanoparticle dispersion type metal ink with a viscosity of 400 cps in Preparation Example 4, through the roll-to-roll dipping process of the third example, the six surfaces of the semiconductor package except the bottom surface are coated on the six surfaces, and then coated on Firing was performed at 130°C for 15 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 50 mΩ/cm ² , the step coverage was 96%, and the shielding rate was 65 dB. Example 15

Using the silver paste-like metallic ink with the viscosity of 50000cps of Preparation Example 5, through the roll-to-roll dipping process of the third example, five of the six surfaces of the semiconductor package except the bottom surface were coated, and then at 130°C The baking was performed for 20 minutes to form an electromagnetic wave shielding film.

The surface resistance of the shielding film thus formed was 60 mΩ/cm ² , the step coverage was 96%, and the shielding rate was 59 dB. Electromagnetic wave shielding film protective coating example 19

The upper layer of the electromagnetic wave shielding film prepared in the embodiment forms a protective coating layer, which passes through the roller-to-roller dipping process of the third embodiment from thermosetting resin to the five sides of the semiconductor package except the bottom side The surface is coated and then fired at 180°C for 10 minutes to form. Example 20

The upper layer of the electromagnetic wave shielding film prepared in the embodiment forms a protective coating, which passes through the roll-to-roll dipping process of the third embodiment from the ultraviolet curing resin to the five sides of the semiconductor package except the bottom side The surface is coated and then UV cured to form. Comparative example of electromagnetic wave shielding coating process Comparative example 1 : Sputtering process

A sputtering device, that is, a DC magnetron sputtering device, was used to form a film using a metal sintered body as a sputtering target. It was carried out under film-forming conditions of room temperature, DC 500 W, and an oxygen concentration of 6%, and was carried out under annealing conditions of 300° C.×1 hour in an atmosphere. Adjust the sputtering angle so that the other five surfaces except the surface with solder balls can be coated, so that the target module is sputtered on the upper and side surfaces to form a SUS/CU/SUS multilayer structure shielding film .

The step coverage of the masking film thus formed was 41%. Comparative Example 2 : Injection process

Using a jetting device (787MS-SS valve), the nanoparticle-dispersed ink with a viscosity of 50 cps in Preparation Example 3 was spray-coated on the upper and side surfaces of the semiconductor package, respectively, and then fired at 130°C for 10 minutes to form an electromagnetic wave Masking film.

The step coverage of the masking film thus formed was 47%. Physical property test results

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

Table 1

The characteristics of the electromagnetic wave shielding films prepared in the examples and formed according to each electromagnetic wave shielding and dipping process are shown in Table 2.

Table 2 Physical properties of electromagnetic wave shielding film according to impregnation process and ink type

Table 3 Comparison of the characteristics of the step coverage of the coating film according to the electromagnetic wave shielding forming process

The scope of rights of the present invention is not limited to the above-mentioned embodiments, and can be implemented in various forms of embodiments within the scope of the appended patent application. Without departing from the spirit of the invention claimed in the scope of the patent application, various ranges that can be changed by those skilled in the art to which the invention belongs fall within the scope of the patent application scope of the invention.

10‧‧‧Conveyor

11‧‧‧Paste Department

20‧‧‧ containment tank

21‧‧‧Water level sensor

22‧‧‧Supply device

23‧‧‧ storage tank

24‧‧‧Immersion roller

25‧‧‧Pressure roller

30‧‧‧Blade

41‧‧‧Pre-dryer

42‧‧‧Final dryer

D‧‧‧Electronic components

M‧‧‧Metallic ink

P‧‧‧Plasma

Step S10‧‧‧Load

Step S20 ‧‧‧Immersion

Step S30‧‧‧Leveling

Step S40 ‧‧‧ firing

Step S50‧‧‧Uninstall

FIG. 1 is a process sequence diagram of an electromagnetic wave shielding coating method according to the first embodiment of the present invention.　　 FIG. 2 is a process diagram shown in steps of FIG. 1. Fig. 3 is an enlarged view of the storage tank shown in Fig. 2. FIG. 4 is a process diagram showing a modification of the impregnation step of the electromagnetic wave shielding coating method according to the first embodiment of the present invention. FIG. 5 is a manufacturing process diagram of the electromagnetic wave shielding coating method according to the second embodiment of the present invention. FIG. 6 is a manufacturing process diagram of the electromagnetic wave shielding coating method according to the third embodiment of the present invention.

Claims (12)

An electromagnetic wave shielding coating method, including: a loading step, attaching one side of an electronic component to a transport carrier; an immersing step, dipping the electronic component attached to the transport carrier in a receiving tank containing metal ink In order to apply metal ink to the exposed outer surface of the electronic component; a firing step to cure the metal ink applied to the electronic component; and an unloading step to separate the electronic component from the transport carrier. The electromagnetic wave shielding coating method according to claim 1, wherein, before the immersing step, a surface treatment step of imparting hydrophilicity to the exposed surface of the electronic component is further performed. The electromagnetic wave shielding coating method according to claim 2, wherein the surface of the electronic component is subjected to plasma treatment in the surface treatment step. The electromagnetic wave shielding coating method according to claim 2, wherein the electronic component attachment surface of the transport carrier has hydrophobicity. The electromagnetic wave shielding coating method according to claim 1, wherein before the firing step, a leveling step of leveling the coating thickness of the metal ink applied on the surface of the electronic component is further performed. The electromagnetic wave shielding coating method according to claim 5, wherein in the leveling step, the metal ink that is excessively coated on the surface of the electronic component in the dipping step is scraped off with a blade, thereby leveling (leveling ) Into a flat shape. The electromagnetic wave shielding coating method according to claim 5, wherein in the leveling step, a blade made of an absorbing material is used to absorb the metal ink excessively coated on the surface of the electronic component in the dipping step, thereby Leveling is flat. The electromagnetic wave shielding coating method according to claim 1, wherein in the immersing step, the immersion depth of the electronic component is controlled according to the specifications of the electronic component attached to the transport carrier. The electromagnetic wave shielding coating method according to claim 8, wherein the receiving tank adjusts the water level of the metal ink to a depth that is the same as or lower than the thickness of the electronic component. The electromagnetic wave shielding coating method according to claim 1, wherein the conveying carrier is composed of a carrier film conveyed in a roll-to-roll manner, an adhesive part is provided on one side of the carrier film, and one side of the electronic component It can be attached to this sticking part. The electromagnetic wave shielding coating method according to claim 10, wherein, in the impregnation step, an impregnating roller controlled to be raised and lowered on the upper side of the receiving tank is used to face the surface of the conveyance carrier to which the electronic component is attached The storage tank is pressurized to control the immersion depth of the electronic component. The electromagnetic wave shielding coating method according to claim 10, wherein in the immersion step, the outer surface of the electronic component moving on the upper side of the immersion roller is coated while the immersion roller absorbing the metallic ink in the containing tank rotates Metallic ink.