Film formation method, resin layer formation apparatus, film formation apparatus, and circuit board with electromagnetic wave shielding

Abstract

The present invention provides a film formation method, a resin layer formation apparatus, a film formation apparatus, and an electromagnetic shielded circuit board that enable thinning while preventing poor connections between the electromagnetic shielding film and the ground wiring. [Solution] The film-forming method of the embodiment is a film-forming method for forming an electromagnetic wave shielding film 150 covering an electronic component 2 on a circuit board 100 having an electronic component 2 and a ground wire 110, comprising: a resin layer forming step of forming a resin layer 140 that seals the inside of a metal frame 130 surrounding the electronic component 2 on the circuit board 100 and in contact with the ground wire 110 with a first resin; and a film-forming step of forming an electromagnetic wave shielding film 150 that covers the top surface of the resin layer 140 so as to be in contact with the metal frame 130.

Description

Technical Field

[0001] The present invention relates to a film forming method, a resin layer forming apparatus, a film forming apparatus, and a circuit board with electromagnetic shielding.

Background Art

[0002] Circuit boards provided in electronic devices such as smartphones and medical devices have electronic components that are easily affected by electromagnetic waves. In order to protect these electronic components from electromagnetic waves, they are covered with aluminum or stainless steel metal cans connected to the ground wiring on the circuit board. At least one or more, generally a plurality of, electronic components are covered by a single metal can. This metal can is manufactured by sheet metal processing and has a limit in thickness reduction. Therefore, the metal can by sheet metal processing hinders further miniaturization and thinning of electronic devices.

[0003] Therefore, as a method to replace the covering of electronic components with a metal can, a plating method and a sputtering method have been proposed. Since the plating method requires a large number of wet processes, an increase in the manufacturing cost of the circuit board is inevitable. Therefore, the sputtering method has attracted particular attention.

[0004] In the sputtering method, as a pre-step, first, a large number of circuit boards are formed side by side on a single wafer. Electronic components are mounted on each circuit board without being separated from the wafer. After mounting the electronic components on each circuit board, a resin layer is formed on the wafer. This resin layer includes a shield planned area that shields (shields) electromagnetic waves in each circuit board and is formed so as to be continuous (see, for example, Patent Document 1). The shield planned area is an area on the circuit board covered with an electromagnetic shielding film. Then, the resin layer of each shield planned area is divided by dicing.

[0005] After this dicing, the target, which will serve as the material source for the electromagnetic shielding film, is placed in the deposition chamber, an inert gas is introduced into the chamber, and a DC voltage is applied. When the plasma-generated inert gas ions collide with the target, the material constituting the target is knocked out as atomic, molecular, or cluster-like particles. The diced resin layer faces the target, and the knocked-out particles accumulate on this resin layer, forming the electromagnetic shielding film on the surface of the resin layer. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2013 / 035819 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In the method where a single continuous resin layer is formed for each circuit board, and then the resin layer is diced for each circuit board, the sides of each resin layer are vertically perpendicular to the circuit board from the base to the top. In the sputtering method, particles ejected from the target by plasma (hereinafter referred to as deposition particles) approach from the top surface of the resin layer. The sides of the resin layer that extend parallel to the direction from which the deposition particles are coming are less likely to be reached by the deposition particles than the top surface of the resin layer.

[0008] Therefore, the electromagnetic shielding film deposited on the surface of the resin layer becomes thinner on the sides of the resin layer. The electromagnetic shielding film is connected to the ground wiring of the circuit board on the side. If the film thickness on the side that connects to the ground wiring is thin, there is a risk of electrical connection failure between the electromagnetic shielding film and the ground wiring.

[0009] Embodiments of the present invention have been made to solve the above-mentioned problems, and their objective is to provide a film formation method, a resin layer formation apparatus, a film formation apparatus, and an electromagnetic shielded circuit board that can be made thinner while preventing poor connection between the electromagnetic shielding film and the ground wiring. [Means for solving the problem]

[0010] An embodiment of the present invention is a method for forming an electromagnetic wave shielding film on a circuit board having an electronic component and ground wiring, the method comprising: a sealing step of forming a resin layer that seals the electronic component by filling a metal frame that surrounds the electronic component on the circuit board and is in contact with the ground wiring with a first resin; and a film formation step of forming an electromagnetic wave shielding film that covers the top surface of the resin layer so as to be in contact with the metal frame.

[0011] The resin layer forming apparatus according to an embodiment of the present invention has a sealing unit that forms a resin layer to seal an electronic component by filling a metal frame surrounding the electronic component on a circuit board and in contact with the ground wiring with a first resin.

[0012] The film-forming apparatus according to an embodiment of the present invention comprises a resin layer forming apparatus and a film-forming unit that forms an electromagnetic wave shielding film on the top surface of the resin apparatus so as to be in contact with the metal frame and covering the top surface of the resin layer.

[0013] An electromagnetic shielded circuit board according to an embodiment of the present invention is a circuit board having electronic components and ground wiring, comprising: a metal frame surrounding the electronic components on the circuit board and in contact with the ground wiring; a resin layer sealing the electronic components within the metal frame; and an electromagnetic shielding film formed on the top surface of the resin layer so as to be in contact with the metal frame and covering the top surface of the resin layer. [Effects of the Invention]

[0014] According to an embodiment of the present invention, it is possible to provide a film forming method, a resin layer forming apparatus, a film forming apparatus, and a circuit board with an electromagnetic wave shield that can prevent a connection failure between an electromagnetic wave shield film and a ground wiring while enabling thinning.

Brief Description of the Drawings

[0015] [Figure 1] It is a schematic diagram showing a circuit board processed by a film forming apparatus. [Figure 2] It is a simplified configuration diagram showing a film forming apparatus of the first embodiment. [Figure 3] It shows a resin layer forming apparatus of a film forming apparatus, (a) is a side view, and (b) is a plan view. [Figure 4] It is a partial cross-sectional side view showing a resin discharge process in a resin sealing process of the first embodiment. [Figure 5] It is a partial cross-sectional side view showing a curing process in the resin sealing process of the first embodiment. [Figure 6] It shows a mask installation process in the resin sealing process of the first embodiment, (A) is a plan view, and (B) is a partial cross-sectional view. [Figure 7] It is an explanatory diagram showing a film forming process of the first embodiment. [Figure 8] It shows a film forming portion of a film forming apparatus, (A) is a perspective plan view, and (B) is a perspective perspective view. [Figure 9] It is an explanatory diagram showing a resin supply process and a local curing process of the second embodiment. [Figure 10] It is an explanatory diagram showing a mold installation process and a mold filling process of the third embodiment. [Figure 11] It is an explanatory diagram showing a sheet holding process, a mold installation process, and a mold filling process of the fourth embodiment. <00​​​​​​​​​​​​[First Embodiment] [Film Forming Apparatus] The first embodiment will be described in detail with reference to the drawings. [Circuit Board] FIG. 1 is a schematic diagram showing a circuit board 100 processed by a film forming apparatus 1 (see FIG. 2). As shown in the plan view of FIG. 1(A) and the partial cross-sectional view of FIG. 1(B), the film forming apparatus 1 encapsulates one or more electronic components 120 on the circuit board 100 with a single resin layer 140, and forms an electromagnetic shielding film 150 on the surface of the resin layer 140.

[0017] The circuit board 100 is a printed board on which an electronic circuit is formed. One or more electronic components 120 are mounted on the circuit board 100. The electronic component 120 is an electronic component that is susceptible to the influence of electromagnetic waves or leaks electromagnetic waves that affect other components. Examples include communication modules mounted on electronic devices such as smartphones and their front and rear circuits. However, as long as the component requires electromagnetic wave shielding, it is not limited to these examples, and resistors, capacitors, coils, transistors, diodes, integrated circuits such as semiconductor ICs and LSIs, or electronic circuit modules formed by modularizing these are also included in the electronic component 120.

[0018] The circuit board 100 includes a ground wiring 110, a metal frame 130, a resin layer 140, and an electromagnetic shielding film 150. The ground wiring 110 is given a ground potential or a fixed potential. The circuit board 100 also has a metal frame 130. The metal frame 130 surrounds the electronic components 120 on the circuit board 100 and is in contact with the ground wiring 110. The metal frame 130 only needs to have conductivity. For example, it is made of SUS. The thickness of the metal frame 130 is, for example, about 0.05 mm to 0.5 mm. The metal frame 130 has a top surface 131 and side surfaces 132. The top surface 131 is a rectangular plate-like body having a rectangular opening 131a. The horizontal width of the top surface 131 is, for example, about 1 to 2 mm.

[0019] The side surface 132 is fixed to the circuit board 100 by bending the edge of the top surface 131. More specifically, the side surface 132 is a surface formed by bending downwards rectangular portions that protrude equally from each of the four sides of the top surface 131. As a result, gaps 132a are formed between the four side surfaces 132. The metal frame 130 is fixed to the circuit board 100 by brazing at the lower edges of the side surfaces 132, and a part of the side surfaces 132 is in contact with the ground wiring 110, so that it is at the same potential as the ground wiring 110.

[0020] The resin layer 140 is a layer formed by resin supplied into the metal frame 130, and it seals the electronic components 120 inside the metal frame 130. Preferably, the top surface of the resin layer 140 reaches the opening 131a of the top surface 131 of the metal frame 130 and is flush with the top surface 131. In other words, it is preferable that the opening 131a is filled and that the resin layer 140 and the top surface 131 of the metal frame 130 form a continuous flat surface.

[0021] The electromagnetic wave shielding film 150 is a film that is in contact with the metal frame 130 and covers the top surface of the resin layer 140. As described later, various film-forming materials can be used as the material for the electromagnetic wave shielding film 150, but for example, it can be a multilayer film combining magnetic materials such as Ni, Fe, Cr, and Co, and non-magnetic materials such as Cu, Al, Ag, Ti, Nb, Pd, Pt, and Zr, or a single layer film of a highly conductive film such as Cu. The film deposition apparatus 1 deposits the electromagnetic wave shielding film 150 so as to be in contact with the metal frame 130. As a result, an electromagnetic wave shielding film 150 is formed on the circuit board 100 that can allow captured electromagnetic noise to flow to the ground wiring 110 via the metal frame 130. The thickness of the electromagnetic wave shielding film 150 is, for example, 1 μm to 10 μm, which is very thin compared to the metal frame 130. Note that Figure 1 shows the electronic component 120 sealed in the resin layer 140 and with the electromagnetic wave shielding film 150 formed on it, but this electronic component 120 is not actually visible to the naked eye. [Film forming equipment] Figure 2 is a simplified configuration diagram of the film deposition apparatus 1 of this embodiment. The film deposition apparatus 1 comprises a resin layer forming apparatus 2 for forming a resin layer 140 and a film deposition section 3 for depositing an electromagnetic wave shielding film 150 on the surface of the resin layer 140. A transport mechanism 4 for transporting the circuit board 100 may be interposed between the resin layer forming apparatus 2 and the film deposition section 3. The transport mechanism 4 only needs to be able to discharge the circuit board 100 from the resin layer forming apparatus 2 and feed it into the film deposition section 3, and for example, a robot arm can be used. The transport mechanism 4 can also use a transport table that moves along a straight trajectory using a conveyor, ball screw, etc. [Resin layer forming device] As shown in Figure 2, a transport path 25 for the circuit board 100 is formed inside the resin layer forming apparatus 2. The circuit board 100 is supported by a tray 251 and moves along the transport path 25. This transport path 25 is, for example, the running surface of a conveyor. The resin layer forming apparatus 2 includes a filling section 21, a curing section 22, and a mask installation section 27 along the transport path 25. (Filling section) As shown in Figure 3, the filling unit 21 has a dispenser equipped with a discharge port 211 and discharges resin that will form the base of the resin layer 140 onto the circuit board 100. The resin discharged by the filling unit 21 is stored in a resin tank (not shown) that communicates with the discharge port 211 via a control valve or the like, and is supplied from the resin tank to the filling unit 21. The discharge port 211 of the filling unit 21 supplies resin into the metal frame 130 from the top of the opening 131a of the metal frame 130 (see Figure 4).

[0022] The resin supplied to the filling section 21 is a thermosetting resin that hardens upon irradiation with thermal energy such as a heater or infrared radiation. Examples of heat-curing resins that can be used include epoxy resin, phenolic resin, unsaturated polyester resin, silicone resin, diallyl phthalate resin, polyimide resin, and urethane resin. However, the resin used here is a highly permeable (low viscosity) resin that penetrates into the gaps between the electronic components 120 mounted on the circuit board 100 and the surface of the circuit board 100, such as an underfill agent. The underfill agent is liquid so that it can be applied by a dispenser. Note that, in order to distinguish it from the second resin described later, the resin used to form the resin layer 140 in this embodiment may be referred to as the first resin. (curing volume) The curing unit 22 cures the resin filled in the metal frame 130. Depending on the type of resin, the curing unit 22 has an irradiation window for irradiating thermosetting resins with thermal energy such as a heater or infrared rays (see Figure 5). The curing unit 22 may also be provided below the circuit board 100 so that it can be heated from above and below.

[0023] As shown in Figure 2, the filling unit 21 and the curing unit 22 are arranged in parallel in this order from upstream to downstream along the transport path 25. Furthermore, as shown in Figures 3(A) and (B), the filling unit 21 and the curing unit 22 are installed on gate-shaped support units 26a that straddle the transport path 25 and are located above the transport path 25. The curing unit 22 is fixed to a fixed support unit 26a because its irradiation window is wide and can irradiate the entire resin inside the metal frame 130 with thermal energy. The support unit 26a has, for example, motor-driven wheels at its ends and is mounted on rails that extend along the transport path 25. The filling unit 21 is fixed to this support unit 26a and is movable along the transport path 25.

[0024] The support section 26a is equipped with a support section 26b on the gate-shaped bridging portion. The support section 26b is movable along the bridging portion of the support section 26a in a direction perpendicular to the transport path 25 (Y-axis direction). For example, the support section 26b is a linear motion mechanism including a rail and a ball screw mechanism that extends along the bridging portion of the support section 26a in a direction perpendicular to the transport path 25. The filling section 21 is fixed to this support section 26b and is movable in a direction along the transport path 25 (X-axis direction) and in a direction perpendicular to the transport path 25 (Y-axis direction) by the support sections 26a and 26b. (Mask installation area) The mask installation section 27 installs the mask 271 on the metal frame 130. As shown in Figure 2, the mask installation section 27 is located downstream of the hardening section 22 in the transport path 25, and the mask 271 is installed on the metal frame 130 of the circuit board 100 on the transport path 25 by a robot arm (not shown). As shown in Figures 6(A) and (B), the mask 271 is a member that overlaps the top surface 131 other than the opening 131a and covers the circuit board 100 around the metal frame 130. More specifically, the mask 271 has a box shape with a top surface that is larger in area than the horizontal plane of the circuit board 100 and sides that are higher than the height of the side surface 132 of the metal frame 130. An exposed opening 271a, which is a rectangular opening larger than the opening 131a and overlapping the top surface 131, is formed on its top surface. The exposed opening 271a is a tapered opening that becomes thinner towards the edge.

[0025] The mask mounting section 27 installs the mask 271 on the metal frame 130 such that the edges of the exposed opening 271a all overlap the top surface 131 and the opening 131a is not covered by the mask 271. More specifically, the mask mounting section 27 grips both sides of the mask 271 and installs it so that the top surface of the mask 271 overlaps the circuit board 100. At this time, a part of the top surface 131 and the opening 131a are exposed from the exposed opening 271a, and the circuit board 100 is covered by the parts other than the exposed opening 271a. As a result, the electromagnetic wave shielding film 150 is formed on the portion exposed by the exposed opening 271a (see Figure 7). In other words, the area where the electromagnetic wave shielding film 150 is formed is defined by the exposed opening 271a. Since the exposed opening 271a is a tapered opening that becomes thinner towards the edge, there is less area that is shaded by deposition particles incident from an oblique direction, and deposition can be carried out right up to the part exposed by the exposed opening 271a. The part exposed by the exposed opening 271a is the top surface of the resin layer 140 and part of the top surface 131 of the metal frame 130 which is continuous with it. Therefore, the electromagnetic wave shielding film 150 covers the entire top surface of the resin layer 140 exposed from the opening 131a, as well as the exposed part of the top surface 131, so that the electromagnetic wave shielding film 150 and the metal frame 130 are electrically connected. [Film forming section] As shown in Figures 8(A) and (B), the film deposition section 3 has a chamber 31 and a load lock chamber 32. The chamber 31 is a cylindrical vacuum chamber that is wider in the radial direction than in the axial direction. The inside of the chamber 31 is divided into several fan-shaped sections by partitions 33 that extend along the radial direction. Processing positions 311 and film deposition positions 312 are assigned to some of the fan-shaped sections.

[0026] The partition section 33 extends from the ceiling to the bottom of the chamber 31, but does not reach the bottom. A rotary table 34 is installed in the space on the bottom side where the partition section 33 is not present. The rotary table 34 has a disc shape coaxial with the chamber 31 and rotates in the circumferential direction. The circuit board 100, which is loaded into the chamber 31 from the load lock chamber 32, is placed on the rotary table 34 and moves in a circular trajectory, circling the processing position 311 and the film deposition position 312.

[0027] Furthermore, in order to maintain the position of the circuit board 100 relative to the rotary table 34, the rotary table 34 is equipped with holding means for holding the circuit board 100, such as grooves, holes, protrusions, jigs, holders, mechanical chucks, or adhesive chucks.

[0028] A surface treatment unit 35 is installed at processing position 311. In this surface treatment unit 35, a process gas such as argon gas is introduced, and a high-frequency voltage is applied to turn the process gas into plasma, generating electrons, ions, and radicals. For example, this surface treatment unit 35 is a cylindrical electrode that opens towards the rotary table 34, and a high-frequency voltage is applied by an RF power supply.

[0029] A sputtering source 36, including a target 361, is installed at the film deposition position 312. The sputtering source 36 applies power to the target 361 with sputtering gas introduced between the target 361 and the rotary table 34. The sputtering gas is an inert gas such as argon, which is converted into plasma by the application of power from the sputtering source 36, and the generated ions collide with the target 361. Film deposition particles are knocked out from the target 361, and these knocked-out film deposition particles are deposited on the resin layer 140 on the circuit board 100 placed on the rotary table 34.

[0030] Target 361 is the material source for the electromagnetic shielding film 150. Target 361 is formed from a magnetic material such as Ni, Fe, Cr, or Co. Alternatively, Al, Ag, Ti, Nb, Pd, Pt, Zr, etc. may be used to form a multilayer film combining non-magnetic materials. Furthermore, materials such as SUS, Ni, Ti, V, Ta, etc. may be used as the underlayer for the electromagnetic shielding film 150, and SUS, Au, etc. may be used as the outermost protective layer. In other words, there may be, for example, two film deposition positions 312. The target material for each film deposition position 312 may be the same material, or different materials may be used to form a multilayer electromagnetic shielding film 150.

[0031] The power supply that applies power to the sputtering source 36 at each film deposition position 312 can be a well-known type, such as a DC power supply, a DC pulse power supply, or an RF power supply. Furthermore, the power supply that applies power to the sputtering source 36 may be provided for each sputtering source 36, or a common power supply may be used and switched using a switch.

[0032] The film deposition unit 3 is formed on the circuit board 100 using a sputtering method, but the film deposition method is not limited to this. For example, the film deposition unit 3 may form the electromagnetic wave shielding film 150 on the circuit board 100 by vapor deposition, spray coating, or other methods. [Film forming method] A film deposition method using the above-described film deposition apparatus 1 will be explained with reference to Figures 3 to 8. This film deposition method is a method for forming an electromagnetic wave shielding film 150 that covers electronic components 120 on a circuit board 100, and is divided into a resin layer formation step of forming a resin layer 140 that seals the inside of a metal frame 130 with resin, and a film deposition step of forming an electromagnetic wave shielding film 150 that covers the top surface of the resin layer 140 so as to be in contact with the metal frame 130.

[0033] As shown in Figure 3, the circuit board 100 is transported along the transport path 25 to the area where the resin layer forming apparatus 2 is located. In the resin layer forming process, as shown in Figure 4, the filling unit 21 dispenses resin onto the circuit board 100 inside the metal frame 130. As a result, the inside of the metal frame 130 is filled with resin R1.

[0034] Next, the circuit board 100 is transported along the transport path 25 to the area where the curing unit 22 is located. As shown in Figure 5, in the curing process, the metal frame 130 of the circuit board 100 is positioned directly beneath the curing unit 22, and the curing unit 22 is activated. The curing unit 22 irradiates thermal energy onto the entire resin R1 within the metal frame 130, curing the resin R1 and forming a resin layer 140.

[0035] Once the curing process is complete, the circuit board 100 is transported along the transport path 25 to the area where the mask installation section 27 is located. Then, as shown in Figures 6(A) and (B), the mask 271 is installed on the circuit board 100 by a robot arm. At this time, the mask 271 is installed in a position where its exposed opening 271a does not overlap with the opening 131a of the metal frame 130, but overlaps with the top surface 131.

[0036] The circuit board 100 with the mask 271 attached is removed from the resin layer forming apparatus 2 and moves to the film formation process in the film formation section 3. In the film formation section 3, as shown in Figure 8, the circuit board 100 is loaded from the load lock chamber 32 and placed on the rotary table 34. As the circuit board 100 is rotated and transported by the rotary table 34, the surface of the circuit board 100 is plasma-cleaned at the processing position 311. Subsequently, as the circuit board 100 is rotated and transported, at the film formation position 312, as shown in Figures 7(A) and (B), the film formation particles P ejected from the target 361 are deposited on the surface of the mask 271 and the resin layer 140. Therefore, as shown in Figure 7(C), the mask 271 is removed from the circuit board 100 after it has been removed from the film formation section 3, creating a circuit board 100 with an electromagnetic wave shielding film 150 deposited on the surface of the resin layer 140.

[0037] Here, the circuit board 100 is not masked only at the exposed opening 271a. The exposed opening 271a does not overlap with the opening 131a of the metal frame 130, but it is mounted in a position that overlaps with the top surface 131, so the electromagnetic shielding film 150 is formed continuously from the top surface of the resin layer 140 onto the metal frame 130. This ensures an electrical connection between the electromagnetic shielding film 150 and the ground wiring 110. [effect] (1) The embodiment described above is a method for forming an electromagnetic wave shielding film 150 to cover an electronic component 120 on a circuit board 100 having an electronic component 120 and a ground wire 110, comprising: a resin layer forming step of forming a resin layer 140 that seals the inside of a metal frame 130 surrounding the electronic component 120 on the circuit board 100 and in contact with the ground wire 110 with resin; and a film forming step of forming an electromagnetic wave shielding film 150 that covers the top surface of the resin layer 140 so as to be in contact with the metal frame 130.

[0038] Furthermore, the resin layer forming apparatus 2 of this embodiment has a filling section 21 for filling resin into a metal frame 130 that surrounds the electronic component 120 on the circuit board 100 and is in contact with the ground wiring 110. Furthermore, the film forming apparatus 1 of this embodiment has a resin layer forming apparatus 2 and a film forming section 3 for forming an electromagnetic wave shielding film 150 on the top surface of the resin layer 140 so as to be in contact with the metal frame 130 and covering the top surface of the resin layer 140. Moreover, this embodiment is a circuit board 100 having an electronic component 120 and ground wiring 110, comprising a metal frame 130 that surrounds the electronic component 120 on the circuit board 100 and is in contact with the ground wiring 110, a resin layer 140 that seals the electronic component 120 within the metal frame 130, and an electromagnetic wave shielding film 150 that is in contact with the metal frame 130 and is formed to cover the top surface of the resin layer 140.

[0039] In this way, a circuit board 100 is created in which the electromagnetic shielding film 150 is in contact with the metal frame 130 that contacts the ground wiring 110. This prevents poor connection between the electromagnetic shielding film 150 and the ground wiring 110, and allows electromagnetic noise absorbed by the electromagnetic shielding film 150 to escape to the ground wiring 110. Furthermore, since there is no metal can covering the top surface of the resin layer 140, the thickness of the top surface can be reduced, making it possible to make the circuit board thinner. For example, if the opening 131a is covered with a metal can (lid) of the same thickness as the metal frame 130, the thickness of the lid would be about 0.05 mm to 0.5 mm, but since the electromagnetic shielding film 150 is about 1 μm to 10 μm thick, it can be made very thin. (2) The resin layer forming method of this embodiment includes a mask setting step in which the metal frame 130 has a top surface 131 having an opening 131a and a side surface 132 fixed to the circuit board 100 by bending the edge of the top surface 131, and the circuit board 100 around the metal frame 130 is covered by a mask 271 that overlaps a part of the top surface 131 other than the opening 131a. The resin layer forming apparatus 2 of this embodiment also has a mask setting section 27 that covers the circuit board 100 around the metal frame 130 by a mask 271 that overlaps a part of the top surface 131 other than the opening 131a.

[0040] Therefore, during film formation, the electromagnetic wave shielding film 150 is formed continuously on a portion of the top surface 131 of the metal frame 130 and on the top surface of the resin layer 140, thus preventing poor connection between the electromagnetic wave shielding film 150 and the ground wiring 110. Furthermore, since the electromagnetic wave shielding effect can also be obtained on the top surface 131, which is part of the metal frame 130, the electromagnetic wave shielding film 150 may or may not be formed on the top surface 131. When using a metal frame that has no top surface 131 and only side surfaces 132, the mask 271 needs to be positioned so as to expose the top surface of the resin layer 140. In contrast, when using the metal frame 130 with a top surface 131 of this embodiment, the mask 271 only needs to be in a position that overlaps a portion of the top surface 131, and its position is not limited as long as it is on the top surface 131. Thus, because there is flexibility in the position of the mask 271 on the top surface 131, even if there is an error in the mounting of the mask 271 and the metal frame 130, poor connection of the deposited electromagnetic shielding film 150 is unlikely to occur. [Second Embodiment] [composition] The film-forming apparatus 1 of this embodiment has the same basic configuration as the first embodiment, so only the different configurations will be described, and the common configurations will be omitted from the description. In this embodiment, as shown in Figure 9, the resin layer forming apparatus 2 has a resin supply unit 23 and a local curing unit 24. The resin supply unit 23 supplies a second resin R2, which has a higher viscosity than the above-mentioned resin R1 (first resin), to a position that closes the gap 132a in the side surface 132 of the metal frame 130. The second resin R2 seals the gap 132a by being applied to the outer circumference of the metal frame 130 (see Figure 1(A)). The resin supply unit 23 is, for example, a dispenser equipped with a discharge port 231. The second resin R2 discharged by the resin supply unit 23 is stored in a resin tank (not shown) that communicates with the discharge port 231 via a control valve or the like, and is supplied from the resin tank to the resin supply unit 23.

[0041] The second resin R2 supplied to the resin supply unit 23 is photocurable and hardens upon irradiation with light energy such as ultraviolet light. The second resin R2 contains, for example, monomers and oligomers involved in the photopolymerization reaction and polymerization initiators, and can be urethane acrylate, epoxy acrylate, acrylate, or epoxy. In addition, the second resin R2 has a higher viscosity than the first resin R1.

[0042] The local curing unit 24 cures the resin supplied to the outer periphery of the metal frame 130 on the circuit board 100. The local curing unit 24 has an irradiation window that irradiates light energy, such as ultraviolet light, onto the photocurable resin, depending on the type of resin dispensed by the resin supply unit 23. The local curing unit 24 cures the resin dispensed by the resin supply unit 23 by irradiating it with light energy.

[0043] These resin supply units 23 and local curing units 24 are located upstream of the filling unit 21 (see Figures 2 and 3). The resin supply units 23 and local curing units 24 are also installed on each support unit 26a and are located above the transport path 25. Similar to the filling unit 21, the resin supply unit 23 is movable in the direction along the transport path 25 (X-axis direction) and in the direction perpendicular to the transport path 25 (Y-axis direction) by the support units 26a and 26b. [Film forming method] Figure 9 is a schematic diagram showing a film deposition method using the film deposition apparatus 1 of this embodiment. This film deposition method includes a resin supply step in which a second resin R2 is supplied to a position that closes the gap 132a in the metal frame 130, before the resin layer formation step. Steps similar to those in the first embodiment will not be described.

[0044] The circuit board 100 is transported along the transport path 25 to the area where the resin supply unit 23 is located. In the resin supply process, as shown in Figures 9(A) and (B), the resin supply unit 23 moves along the outer circumference of the metal frame 130 with the support parts 26a and 26b, and discharges the second resin from the discharge port 231, thereby applying the second resin R2 along the side surface 132 of the metal frame 130 and sealing the gap 132a. After application, as shown in Figure 9(C), the local curing treatment unit 24 cures the applied second resin R2 by irradiating it with light energy. The subsequent steps are the same as the resin layer formation process and film formation process of the first embodiment described above. [effect] In this embodiment, as described above, a resin supply unit 23 is provided to supply a second resin R2, which has a higher viscosity than the first resin R1, to a position that closes the gap 132a in the metal frame 130 before the resin layer formation process. Therefore, when the first resin R1 is filled into the metal frame 130 during the resin layer formation process, leakage of the first resin R1 from the gap 132a in the metal frame 130 is prevented. This is particularly effective when the first resin R1 is a highly fluid underfill agent. Furthermore, during film formation, it is prevented that the film-forming particles wrap around the film and form a circuit pattern. [Third Embodiment] [composition] Since the film-forming apparatus 1 of this embodiment has the same basic configuration as the first embodiment, only the different configurations will be described, and the common configurations will be omitted from the explanation. In this embodiment, as shown in Figure 10, the resin layer forming apparatus 2 has a mold installation section 28 and a mold filling section 29. The mold installation section 28 is located in the transport path 25, replacing the filling section 21 and curing section 22 of the first embodiment.

[0045] The mold installation section 28 installs the mold 281 on the circuit board 100 so as to cover the metal frame 130. The mold 281 consists of an upper mold 281A that covers the circuit board 100 from the side of the metal frame 130 to be sealed, and a lower mold 281B that covers it from the opposite side. The upper mold 281A has a cavity 282 that reaches the height of the metal frame 130. The cavity 282 is a rectangular parallelepiped-shaped void having a ceiling 282a and an inner circumferential surface 282b. The ceiling 282a of the cavity 282 is a flat surface, and its height is the same as the height of the top surface 131 of the metal frame 130. Therefore, when the upper mold 281A is installed on the circuit board 100, the ceiling 282a of the cavity 282 is in contact with the top surface 131 of the metal frame 130 (see Figure 10(B)). Furthermore, the inner circumferential surface 282b of the cavity 282 surrounds the side surface 132 of the metal frame 130.

[0046] The lower mold 281B is provided with a housing area 283, which is an air gap in which the circuit board 100 is housed, in order to sandwich and seal the circuit board 100 between it and the upper mold 281A. The circuit board 100 is provided so that it can be housed in the housing area 283 of the lower mold 281B from the transport path 25 by a robot arm (not shown).

[0047] Furthermore, the mold mounting section 28, although not shown in the figures, has an opening and closing mechanism for opening and closing the mold 281. The opening and closing mechanism covers and closes the circuit board 100 installed inside the lower mold 281B by moving the upper mold 281A and the lower mold 281B relative to each other, and then opens the circuit board 100 after resin sealing.

[0048] The mold filling section 29 is configured within the upper mold 281A and the lower mold 281B, and a resin layer 140 that seals the electronic component 120 is formed by filling the metal frame 130 with the first resin R1. The first resin R1 can be the same type of thermosetting resin used in the filling section 21 of the first embodiment described above. However, in this embodiment, a solid resin material (hereinafter referred to as pellet L) is melted at a high temperature and filled into the mold 281.

[0049] The mold filling section 29 includes a pressurizing chamber 291, a heating cylinder 292, and a gate 293. The pressurizing chamber 291 is a space in which pellets L are contained and heated and pressurized. The heating cylinder 292 is slidably installed to seal the inside of the pressurizing chamber 291 and heats, melts, and pressurizes the pellets L contained in the pressurizing chamber 291. The heating cylinder 292 is heated to approximately 150-250°C by a heater (not shown). The gate 293 is a resin supply path connecting the pressurizing chamber 291 and the cavity 282. [Film forming method] Figure 10 is a schematic diagram showing a film deposition method using this film deposition apparatus 1. This film deposition method includes a mold setting step of setting a mold 281 on the circuit board 100 so as to cover the metal frame 130 in order to form a resin layer 140, and a mold filling step of filling the cavity 282 with resin. Steps similar to those in the first embodiment will not be described.

[0050] First, the mold installation process will be explained. The circuit board 100 is transported along the transport path 25 to the area where the mold installation section 28 is located. In the mold installation section 28, as shown in Figure 10(A), a robot arm moves the circuit board 100 from the transport path 25 into the housing area 283 of the lower mold 281B. At the same time, resin pellets L are loaded into the lower mold 281B, which constitutes the pressurizing chamber 291. Then, as shown in Figure 10(B), the upper mold 281A is moved relative to the lower mold 281B by an opening and closing mechanism, and the upper mold 281A is closed and fixed so as to cover the circuit board 100 installed inside the lower mold 281B. Since the height of the cavity 282 of the upper mold 281A is the same as the height of the metal frame 130, the top surface 131 of the metal frame 130 and the ceiling 282a of the cavity 282 come into contact. Furthermore, the pressurized chamber 291 contains the resin material pellets L placed on the heating cylinder 292.

[0051] Next, the mold filling process will be explained. As described above, pellets L are contained in the pressurizing chamber 291. As shown in Figure 10(C), the heating cylinder 292 is heated to approximately 150-250°C by a heater, melting the pellets L placed on the heating cylinder 292. Then, by pushing up the heating cylinder 292, the molten first resin R1 is injected into the cavity 282 through the gate 293. As shown in Figure 10(D), the first resin R1 injected from the gate 293 penetrates into the metal frame 130 through the gaps 132a at the four corners of the metal frame 130 and the gap between the lower end of the metal frame 130 and the surface of the circuit board 100, filling the inside of the metal frame 130, reaching the ceiling 282a inside the cavity 282, and filling the opening 131a of the metal frame 130. In this way, the injected first resin R1 fills the entire cavity 282.

[0052] The first resin R1 poured into the cavity 282 is cooled under pressure for a predetermined time by the heating cylinder 292 until it hardens. Furthermore, as shown in Figure 10(E), after the first resin R1 has hardened, the opening / closing mechanism moves the upper mold 281A relative to the lower mold 281B to open the circuit board 100. Then, a robot arm removes the circuit board 100, which has been sealed with resin inside the metal frame 130. The burrs B at the ends (the parts enclosed by dotted lines in the figure) are then separated from the hardened resin. This separation can be done manually or using a special jig. In this way, a circuit board 100 with a resin layer 140 formed inside the metal frame 130 can be created. Because the upper end of the resin layer 140 is restricted by the flat ceiling 282a of the cavity 282, the top surface of the resin layer 140 and the top surface 131 of the metal frame 130 become flush, forming a flat surface.

[0053] As shown in Figure 5, the opening and closing mechanism raises the upper mold 281A, and the robot arm returns the circuit board 100 on which the resin layer 140 has been formed to the transport path 25. The subsequent mask installation process and film formation process are the same as in the embodiment described above. [effect] As described above, this embodiment includes a mold installation section 28 for installing a mold 281 having a cavity 282 reaching the height of the metal frame 130 on the circuit board 100 so as to cover the metal frame 130, and a mold filling section 29 for filling the cavity 282 with the first resin R1. Therefore, the resin can be filled to the same height as the metal frame 130, and an electromagnetic wave shielding film 150 can be formed on the upper end of the metal frame 130 during film formation. Thus, a flat electromagnetic wave shielding film 150 can be formed. The electromagnetic wave shielding film 150 exhibits an electromagnetic wave shielding effect when the direction of the magnetic field generated from the current flowing through the electronic components 120 on the circuit board 100 and the direction of magnetization of the electromagnetic wave shielding film 150 are nearly parallel. If the electromagnetic wave shielding film 150 is a flat surface with few irregularities, the direction of the magnetic field will be nearly parallel to the top surface of the resin layer 140, and by forming the electromagnetic wave shielding film 150 on a flat surface with few irregularities, shielding characteristics can be exhibited. [Fourth Embodiment] The film deposition apparatus 1 of this embodiment has the same basic configuration as the third embodiment, so only the different configurations will be described, and the common configurations will be omitted from the description. In this embodiment, as shown in Figure 11, there is a sheet holding section 400 for holding the sheet 410 between the cavity 282 of the mold 281 and the metal frame 130. The sheet holding section 400 is a box-shaped container that is airtightly fixed to the upper part of the upper mold 281A, and a negative pressure supply chamber 420 is provided inside. The negative pressure supply chamber 420 is configured to be able to be exhausted by a negative pressure generating circuit (not shown) through an exhaust hole 421 provided on the top surface. The negative pressure supply chamber 420 is also in communication with a plurality of intake holes 282c that penetrate the ceiling 282a of the cavity 282 of the upper mold 281A, and an intake hole 282d that penetrates the ceiling of the pressurizing chamber 291.

[0054] A sheet 410 is provided on the lower surface of the upper mold 281A, that is, the surface facing the lower mold 281B, so as to be able to hold it. The sheet 410 is a release-type film. For example, a PET film coated with Si or PTFE to give release properties to one or both sides can be used as the sheet 410. By placing this sheet 410 on the lower surface of the upper mold 281A and exhausting it from the exhaust port 421 of the negative pressure supply chamber 420 by the negative pressure generation circuit, the sheet 410 can be adsorbed to the ceiling 282a of the cavity 282 and the ceiling of the pressurized chamber 291 via the intake ports 282c and 282d.

[0055] Here, to account for dimensional errors between the metal frame 130 and the cavity 282, and to prevent friction between the cavity 282 and the metal frame 130 when covering the metal frame 130, a gap is created between the cavity 282 and the metal frame 130. In this embodiment, the sheet 410 is held on the lower surface of the upper mold 281A as described above, sealing the gap between the ceiling 282a of the cavity 282 and the top surface 131 of the metal frame 130. The upper part of the gate 293 is also covered by the sheet 410, but the flow path of the gate 293 is secured when the upper mold 281A and the lower mold 281B are aligned. [Film forming method] Figure 11 is a schematic diagram showing a film deposition method using this film deposition apparatus 1. This film deposition method includes a sheet holding step in which the sheet 410 is held between the cavity 282 and the metal frame 130. Steps similar to those in the third embodiment will not be described.

[0056] First, as described above, the circuit board 100 is housed in the housing area 283 of the lower mold 281B, and resin pellets L are placed in the portion constituting the pressurized chamber 291 of the lower mold 281B. As shown in Figure 11(A), the sheet 410 is inserted so as to cover the lower surface of the upper mold 281A, and the negative pressure generation circuit exhausts air from the exhaust port 421 of the negative pressure supply chamber 420, causing the sheet 410 to adhere to the ceiling 282a of the cavity 282 and the ceiling of the pressurized chamber 291 via the intake ports 282c and 282d. Then, as shown in Figure 11(B), the upper mold 281A is moved relative to the lower mold 281B by the opening and closing mechanism, and closed to cover and fix the circuit board 100 installed inside the lower mold 281B.

[0057] Next, as shown in Figures 11(C) and (D), similar to the third embodiment, in the mold filling process, after the resin hardens and the resin layer 140 is formed, the upper mold 281A is moved relative to the lower mold 281B by the opening and closing mechanism, as shown in Figure 11(E), thereby separating the upper mold 281A from the lower mold 281B. At this time, since suction from the intake holes 282c and 282d of the upper mold 281A is continued, the sheet 410 is adsorbed to the lower surface of the upper mold 281A and released from the circuit board 100. The subsequent steps are the same as in the third embodiment. [effect] As described above, this embodiment has a sheet holding portion 400 between the cavity 282 and the metal frame 130 for holding the sheet 410. Therefore, the gap between the top surface 131 of the metal frame 130 and the ceiling 282a of the cavity 282, and the gap between the side surface 132 of the metal frame 130 and the inner circumferential surface 282b of the cavity 282 are filled, preventing the first resin R1 from entering and spreading, and thus preventing poor connection between the electromagnetic wave shielding film 150 and the metal frame 130. [Differentiation] (1) In the third and fourth embodiments described above, a resin layer 140 covered by a metal frame 130 can also be formed on both sides of the circuit board 100. In this case, as shown in Figure 12, the lower mold 281B is provided with a housing area 283 capable of housing the metal frame 130 together with the resin layer 140 formed on one side of the circuit board 100. This allows the resin layer 140 to be formed on the other side in the same manner as described above. (2) As shown in Figure 13, the film deposition apparatus 1 is configured such that the resin layer forming apparatus 2 and the film deposition section 3 are arranged in a reduced-pressure chamber capable of creating a vacuum, and may be connected by a vacuum transport chamber 500 having a transport mechanism 4. As a result, the circuit board 100 formed in the resin layer forming apparatus 2 is transported under vacuum by the transport mechanism 4 and brought into the film deposition section 3. Therefore, the series of processes of resin layer formation and film deposition can be carried out without the circuit board 100 being exposed to the atmosphere.

[0058] Here, if the exposure time to the atmosphere is long (for example, 10 minutes or more), moisture-containing gases will be adsorbed onto the formed resin layer 140. If the circuit board 100 in this state is then transported to the film deposition section 3, the vacuum level during the film deposition process deteriorates, and the film quality worsens. Therefore, in a configuration where the resin layer forming apparatus 2 is transported to the film deposition section 3 via atmospheric transport, it was sometimes necessary to perform a degassing treatment by baking the circuit board 100 before transporting it to the film deposition section 3. However, as described above, by performing the series of processes in a vacuum, the adsorption of moisture-containing gases from the atmosphere can be prevented, thus eliminating the need for degassing treatment and shortening the processing time. (3) A surface treatment area may be provided upstream of the filling section 21 area in the resin layer forming apparatus 2 in the transport path 25 of the circuit board 100, and the surface of the circuit board 100 may be cleaned before the resin sealing process to remove the natural oxide film that has formed on the ground wiring 110. This allows for good electrical connection between the ground wiring 110 and the electromagnetic wave shielding film 150, further reducing contact problems. [Other embodiments] The present invention is not limited to the embodiments described above, and these novel embodiments can be implemented in various other forms. These embodiments can be modified in various ways without departing from the scope of the invention, and such modifications are included in the scope and essence of the invention, as well as in the invention described in the claims. [Explanation of symbols]

[0059] 1 Film deposition equipment 2 Resin layer forming device 3 Film forming section 4. Conveying mechanism 21 Filling section 22. Curing treatment process 23 Resin supply unit 24 Local hardening treatment 25. Transport Route 26a, 26b Support part 27 Mask installation area 28 Mold installation section 29 Mold filling section 31 Chambers 32 Load Lock Room 33 Sections 34 Rotating Table 35 Surface treatment 36 Sputtering source 100 circuit boards 110 Ground wiring 120 Electronic Components 130 Metal frame 131 Top surface 131a opening 132 Side view 132a Gap 140 resin layer 150 Electromagnetic wave shielding film 211,231 Discharge port 251 Tray 271 masks 271a Exposed mouth 281 molds 281A upper mold 281B Lower mold 282 Cavity 282a Ceiling 282b Inner surface 282c, 282d intake ports 283 Containment Area 291 Pressurized chamber 292 Heating Cylinder Gate 293 311 Processing Position 312 Deposition Position 361 Target 400 Sheet holding section 410 seats 420 Negative pressure supply chamber 500 Vacuum Transfer Chamber

Claims

1. A method for forming an electromagnetic shielding film covering an electronic component on a circuit board having an electronic component and ground wiring, A resin layer forming step is to form a resin layer that seals the inside of a metal frame surrounding the electronic components on the circuit board and in contact with the ground wiring with a first resin, A film formation step in which an electromagnetic wave shielding film is formed to cover the top surface of the resin layer so as to be in contact with the metal frame, A film formation method having the following characteristics.

2. The film-forming method according to claim 1, wherein in the resin layer forming step, the first resin is filled into the metal frame by a filling unit that discharges the first resin.

3. The film-forming method according to claim 2, further comprising a resin supply step of supplying a second resin with a higher viscosity than the first resin to a position that closes the gaps in the metal frame, prior to the resin layer formation step.

4. The resin layer formation step is, A mold installation step involves installing a mold having a cavity that reaches the height of the metal frame onto the circuit board so as to cover the metal frame, A mold filling step of filling the cavity with a first resin, A film formation method according to claim 1, comprising:

5. The film forming method according to claim 4, wherein the resin layer forming step includes a sheet holding step of holding a sheet between the cavity and the metal frame.

6. The metal frame has a top surface with an opening and a side surface whose edge is bent and fixed to the circuit board. The method for forming a film according to any one of claims 1 to 5, further comprising a step of installing a mask that covers the circuit board around the metal frame by covering a part of the top surface other than the opening with the mask.

7. A resin layer forming apparatus having a filling section for filling a first resin into a metal frame that surrounds electronic components on a circuit board and is in contact with ground wiring.

8. The resin layer forming apparatus according to claim 7, further comprising a resin supply unit that supplies a second resin with a higher viscosity than the first resin at a position that closes the gaps in the side surface of the metal frame.

9. A mold mounting section is provided for mounting a mold having a cavity that reaches the height of the metal frame onto the circuit board so as to cover the metal frame, A mold filling section for filling the cavity with the first resin, A resin layer forming apparatus according to claim 8, having the following features.

10. The resin layer forming apparatus according to claim 9, further comprising a sheet holding portion for holding a sheet between the cavity and the metal frame.

11. The metal frame has a top surface with an opening and a side surface whose edge is bent and fixed to the circuit board. A resin layer forming apparatus according to any one of claims 7 to 10, having a mask installation portion that covers the periphery of the metal frame by a mask that overlaps a part of the top surface other than the opening.

12. A resin layer forming apparatus according to any one of claims 7 to 11, A film-forming section for forming an electromagnetic wave shielding film that covers the top surface of the resin layer so as to be in contact with the metal frame, A film deposition apparatus having

13. A circuit board having electronic components and ground wiring, A metal frame surrounding the electronic component on the circuit board and in contact with the ground wiring, A resin layer that seals the electronic components within the metal frame, An electromagnetic wave shielding film is formed on the top surface of the resin layer, in contact with the metal frame and covering the top surface of the resin layer. A circuit board with electromagnetic shielding.

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