Shielding component, electronic device, and method for manufacturing the shielding component

Abstract

To provide a shield component and the like that can contribute to stabilizing the bonding between a plating layer of the shield component and a lead-free solder.SOLUTION: The shield component comprises: a metal plate having a plating layer on an underlying metal plate; and a plurality of hydrophilic blocks arranged in a dot pattern at optional or predetermined intervals on the plating layer. The hydrophilic blocks may be made of an ultraviolet-curable resin, and the surface of the hydrophilic blocks may have an uneven surface having a plurality of recesses or protrusions.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a shielding component, an electronic device, and a method for manufacturing the shielding component. [Background technology]

[0002] Printed wiring boards used in electronic devices often feature shielding components (such as shield covers and shield cases) that encase the electronic components to protect them from the effects of electromagnetic waves and radiation. The shielding components are fixed to the conductor patterns of the printed wiring board with solder and electrically connected to ground. Environmental conservation efforts have led to the restriction of lead solder, and the use of lead-free solder has shifted to this practice. Lead-free solder has the property of being less likely to wet and spread on conductor patterns than lead solder due to differences in surface tension, interfacial tension, formation of a stable oxide film, and electrochemical factors (electrode potential). This lack of wettability can lead to defects such as a failure to form a solder bond. Failure to form a solder bond reduces the shielding effect and the adhesive strength between the shielding component and the board, resulting in an unsuitable product. Therefore, it is desirable for lead-free solder to wet and spread (reducing the contact angle) not only on the conductor patterns but also on the shielding components.

[0003] As an example of a method for allowing lead-free solder to wet and spread on a shielding component, Patent Document 1 discloses a method in which a plating layer is formed on the surface of a base steel sheet and irregularities are formed on the surface of the plating layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2002-232185 Summary of the Invention [Problem to be solved by the invention]

[0005] The following analysis is provided by the present inventors.

[0006] However, in the shielding component of Patent Document 1, the entire surface of the shielding component is covered with a plated layer, and the thickness of the plated layer is not uniform due to unevenness. Therefore, during the manufacturing process of the shielding component, the plated layer may be altered, chipped, or thinned in some areas, which may result in an unstable bond between the plated layer and the lead-free solder.

[0007] The main object of the present invention is to provide a shielding component, an electronic device, and a method for manufacturing a shielding component that can contribute to stabilizing the bond between the plating layer of the shielding component and lead-free solder. [Means for solving the problem]

[0008] A shielding component according to a first aspect comprises a metal plate having a plating layer on a base metal plate, and a plurality of hydrophilic blocks arranged in a dot pattern on the plating layer at arbitrary or predetermined intervals. In particular, it is preferable that the surface area per unit volume of the hydrophilic block is higher than the surface area per unit volume of the plated layer.

[0009] An electronic device according to a second aspect includes a printed wiring board having a conductor pattern, an electronic component mounted on the printed wiring board, and the shielding component according to the first aspect, which is arranged to cover the electronic component and is fixed to the conductor pattern of the printed wiring board by lead-free solder.

[0010] A method for manufacturing a shielding component according to a third aspect includes the steps of forming a plating layer on a base metal plate, and forming a plurality of hydrophilic blocks in a dot pattern on the plating layer at arbitrary or predetermined intervals. In particular, it is preferable that the surface area per unit volume of the hydrophilic block is higher than the surface area per unit volume of the plated layer. [Effects of the Invention]

[0011] The first to third aspects can contribute to stabilizing the bond between the plating layer of the shielding component and the lead-free solder. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view schematically illustrating an example of a configuration of a shielding component according to the present disclosure. [Figure 2] 1A is a plan view schematically illustrating a first example of the configuration of a shielding component according to the present disclosure, and FIG. 1B is an enlarged plan view of a region R1. [Figure 3] 2(B) is a cross-sectional view taken along line XX' in FIG. 2(B) and schematically showing a first example of the configuration of a shielding component according to the present disclosure. [Figure 4] 1A is a perspective view schematically illustrating a first example of the configuration of a hydrophilic block of a shield component according to the present disclosure, and FIG. 1B is a cross-sectional view taken along line YY′. [Figure 5] 1A to 1C are partial cross-sectional views schematically illustrating steps in a method for manufacturing a shielding component according to the present disclosure. [Figure 6] 10 is a partial cross-sectional view schematically illustrating a second example of the configuration of a shield component according to the present disclosure. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] The following description of the embodiments will be made with reference to the drawings. Note that, when reference numerals are used in this application, they are intended solely to aid understanding and are not intended to limit the present invention to the illustrated embodiments. Furthermore, the following embodiments are merely examples and do not limit the present invention.

[0014] [Form 1] The shielding component according to the first embodiment will be described with reference to the drawings. FIG. 1 is a perspective view schematically illustrating an example of the configuration of the shielding component according to the present disclosure. FIG. 2 is (A) a plan view schematically illustrating a first example of the configuration of the shielding component according to the present disclosure, and (B) an enlarged plan view of region R1. FIG. 3 is a cross-sectional view taken along line X-X' in FIG. 2(B) schematically illustrating the first example of the configuration of the shielding component according to the present disclosure. FIG. 4 is (A) a perspective view schematically illustrating a first example of the configuration of the hydrophilic block of the shielding component according to the present disclosure, and (B) a cross-sectional view taken along line Y-Y'.

[0015] The shielding component 10 is a component arranged to cover an electronic component (e.g., a semiconductor package; not shown) mounted on a printed wiring board (e.g., a motherboard; not shown) mounted in an electronic device (e.g., a communication device, a power supply device, etc.) to protect the electronic component from the effects of electromagnetic waves and radiation (see FIG. 1). The shielding component 10 is fixed to a conductor pattern (not shown) on the printed wiring board (not shown) by solder (not shown) and electrically connected to ground. The shielding component 10 is configured by arranging multiple hydrophilic blocks 12 in a dot pattern (polka dots) at arbitrary or predetermined intervals on the surface of a metal plate 11 (plating layer 11b) to improve the bonding between the surface of the shielding component 10 and the solder. The shielding component 10 can be molded into any shape. For example, it may be folded at a molding portion 13 to be molded into a cover shape as shown in FIG. 1, or may be molded into a box shape.

[0016] The metal plate 11 is a plate-like member having a plating layer 11b on a metal substrate 11a (see FIGS. 1 to 3). The metal substrate 11a may be, for example, a stainless steel plate, an aluminum plate, a brass plate, a nickel silver plate, or a tin plate. The plating layer 11b may be made of a metal that allows lead-free solder to easily wet and spread thereon, such as Ni, Zn, Cu, Al, or Sn, or a combination of two or more of these. Examples of lead-free solder that may be used include Sn-Zn, Sn-Ag, Sn-Ag-Cu, Sn-Bi, Sn-Zn-Bi, Sn-Cu, Sn-Ag-In-Bi, and Sn-Zn-Al-based solders. Here, among the factors affecting the wettability of solder, focusing on surface tension, it is known that if a substance has a hydrophilic surface, the larger the surface area, the smaller the contact angle (see Wenzel's equation; RN Wenzel, J.Phys., Colloid Chem. 53, 1466 (1949)). However, the inventors of the present application have discovered that if the surface area of ​​the plating layer 11b is increased by thermal processing, chemical processing (corrosion), or physical processing, it becomes difficult to form a solder bond between the lead-free solder and the plating layer 11b.

[0017] The hydrophilic block 12 is a block having hydrophilic properties (see FIGS. 1 to 4). The hydrophilic property of the hydrophilic block 12 is higher than that of the plating layer 11b. The hydrophilic block 12 is made of a hydrophilic material, such as an ultraviolet-curable resin, and may be an ultraviolet-curable acrylic resin or ultraviolet-curable urethane resin. The wettability of the hydrophilic block 12 with lead-free solder is higher than that of the plating layer 11b. The surface area per unit volume of the hydrophilic block 12 can be higher than that of the plating layer 11b. The hydrophilic block 12 can be formed using a printing technique such as photoimprinting, screen printing, or thermal transfer. The surface (plane or side) of the hydrophilic block 12 can be an uneven surface (including a stepped surface or a conical surface) having a plurality of fine concave or convex portions (see FIG. 4(B)). The shape and arrangement of the concave portions on the uneven surface are arbitrary. The hydrophilic blocks 12 are arranged in a dot pattern (polka dots) on the surface of the metal plate 11 at arbitrary or predetermined intervals so as not to overlap. This allows the surface of the metal plate 11 (plated layer 11b) necessary for solder bonding to be exposed, while the surface of the metal plate 11 is not damaged, thereby increasing the surface area of ​​the shielding component 10 including the hydrophilic blocks 12, reducing the contact angle, and improving solder wettability. The shape (planar shape) of the hydrophilic blocks 12 is arbitrary and is not limited to a rectangle (square), but may be a circle, triangle, or other shape. The arrangement of the hydrophilic blocks 12 is also arbitrary.

[0018] Next, a method for manufacturing a shielding component according to embodiment 1 will be described with reference to the drawings. Figure 5 is a partial cross-sectional view schematically illustrating steps in the method for manufacturing a shielding component according to the present disclosure.

[0019] First, a plate-shaped base metal sheet 11a that has not been press-formed is prepared (see FIG. 5(A)), and a plating layer 11b is formed on the base metal sheet 11a using a plating technique (see FIG. 5(B)). This results in a metal sheet 11 having a plating layer 11b on the base metal sheet 11a. Note that the base metal sheet 11a may be cut into a predetermined shape before the plating layer 11b is formed so that the base metal sheet 11a will have a cover-like, box-like, or other shape when press-formed.

[0020] Next, multiple hydrophilic blocks 12 are formed on the metal plate 11 (on the plating layer 11b) in the form of dots (or polka dots) at arbitrary or predetermined intervals (see FIG. 5(C)). The hydrophilic blocks 12 can be formed, for example, using a photoimprinting method, i.e., by applying a liquid UV-curable resin onto the plating layer 11b, pressing a transparent mold onto the UV-curable resin, and photo-curing the UV-curable resin by irradiating it with UV light. During printing, the hydrophilic blocks 12 are printed at regular intervals while exposing the surface of the metal plate 11 (plating layer 11b) to be soldered. Alternatively, concave and convex portions can be formed on the surface of the hydrophilic blocks 12. Forming the concave and convex portions increases the surface area, reducing the contact angle and facilitating the wetting and spreading of lead-free solder on the shielding component 10.

[0021] Next, the metal plate 11 including the hydrophilic block 12 is press-molded into a predetermined shape to produce a shielding component 10 having a molded portion 13 (for example, a shielding component 10 having a shape as shown in FIG. 1) (see FIG. 5(D)).

[0022] The shielding component 10 thus fabricated is bonded to a conductor pattern (not shown) of a printed wiring board (not shown) with lead-free solder (not shown) so as to cover an electronic component (not shown) mounted on the printed wiring board. When molten solder comes into contact with the surface of the shielding component 10, the solder easily wets and spreads over the surface of the shielding component 10, improving solder bonding.

[0023] According to form 1, the hydrophilic block 12 is formed on the plating layer 11b to increase the surface area of ​​the shielding component 10, thereby reducing the contact angle of the lead-free solder on the surface of the shielding component 10 and improving the wettability of the lead-free solder, thereby contributing to stabilizing the bond between the exposed plating layer 11b of the shielding component 10 and the lead-free solder.

[0024] Furthermore, according to form 1, the surface area of ​​the shielding component 10 is increased by forming the hydrophilic block 12 without using thermal processing, chemical processing (corrosion), or physical processing on the plating layer 11b of the metal plate 11, so that the plating layer 11b is not altered, chipped, or thinned, and the solder bonding on the surface of the shielding component 10 can be stabilized.

[0025] Furthermore, according to form 1, the hydrophilic block 12 is formed on the plating layer 11b while partially exposing the plating layer 11b necessary for solder bonding, thereby improving the wettability of the lead-free solder on the surface of the shielding component 10 and fusing the lead-free solder with the plating layer 11b to ensure solder bonding.

[0026] [Form 2] The shielding component according to the second embodiment will be described with reference to the drawings. Fig. 6 is a partial cross-sectional view schematically showing a second example of the configuration of the shielding component according to the present disclosure.

[0027] The shielding component 10 comprises a metal plate 11 having a plating layer 11b on a base metal plate 11a, and a plurality of hydrophilic blocks 12 arranged in a dot pattern on the plating layer 11b at arbitrary or predetermined intervals.

[0028] According to form 2, by forming a hydrophilic block 12 on the plating layer 11b, the surface area of ​​the shielding component 10 can be increased, thereby reducing the contact angle of the lead-free solder on the surface of the shielding component 10 and improving the wettability of the lead-free solder, which can contribute to stabilizing the bond between the exposed plating layer 11b of the shielding component 10 and the lead-free solder.

[0029] Some or all of the above aspects may be described as, but are not limited to, the following supplementary notes.

[0030] [Appendix 1] a metal plate having a plating layer on a base metal plate; a plurality of hydrophilic blocks arranged in a dot pattern on the plating layer at arbitrary or predetermined intervals; A shielding component comprising: [Appendix 2] 2. The shielding component according to claim 1, wherein the wettability of the lead-free solder to the hydrophilic block is higher than the wettability of the lead-free solder to the plating layer. [Appendix 3] 3. The shielding component according to claim 1, wherein the surface area per unit volume of the hydrophilic block is greater than the surface area per unit volume of the plating layer. [Appendix 4] 4. The shielding component according to any one of appendixes 1 to 3, wherein the base metal plate is a stainless steel plate, an aluminum plate, a brass plate, a nickel silver plate, or a tin plate. [Appendix 5] 5. The shielding component according to claim 1, wherein the plating layer is made of Ni, Zn, Cu, Al, Sn, or a combination of two or more of these. [Appendix 6] 6. The shielding component according to claim 1, wherein the hydrophilic block has a higher hydrophilicity than the plating layer. [Appendix 7] 7. The shielding component according to claim 1, wherein the hydrophilic block is made of an ultraviolet curable resin. [Appendix 8] 7. The shielding component according to any one of claims 1 to 6, wherein the surface of the hydrophilic block is an uneven surface having a plurality of recesses or protrusions. [Appendix 9] a printed wiring board having a conductor pattern; an electronic component mounted on the printed wiring board; a shielding component according to any one of appendices 1 to 8, which is arranged to cover the electronic component and is fixed to the conductor pattern of the printed wiring board by lead-free solder; An electronic device comprising: [Appendix 10] forming a plating layer on a base metal sheet; forming a plurality of hydrophilic blocks in a dot pattern on the plating layer at arbitrary or predetermined intervals; A method for manufacturing a shielding component, comprising: [Appendix 11] In the step of forming the plurality of hydrophilic blocks, a liquid ultraviolet curing resin is applied onto the plating layer, a transparent mold is pressed against the ultraviolet curing resin, and ultraviolet light is irradiated to photo-cure the ultraviolet curing resin, thereby forming the plurality of hydrophilic blocks. 11. A method for manufacturing a shielding component according to claim 10. [Appendix 12] In the step of forming the plurality of hydrophilic blocks, the plurality of hydrophilic blocks are formed so that the surfaces of the hydrophilic blocks have an uneven surface having a plurality of recesses or protrusions. 12. A method for manufacturing a shielding component according to claim 10 or 11. [Appendix 13] a step of press-forming the base metal plate, including the hydrophilic blocks and the plating layer, into a predetermined shape after the step of forming the plurality of hydrophilic blocks; A method for manufacturing a shielding component according to any one of appendices 10 to 12.

[0031] The disclosures of the above-cited patent documents are incorporated herein by reference and may be used as the basis or part of the present invention, as necessary. Modifications and adjustments of the embodiments are possible within the scope of the entire disclosure of the present invention (including the claims and drawings), and further based on the basic technical concept thereof. Furthermore, various combinations and selections (or non-selections, as necessary) of the various disclosed elements (including each element of each claim, each element of each embodiment or embodiment, each element of each drawing, etc.) are possible within the scope of the entire disclosure of the present invention. In other words, the present invention naturally includes various modifications and alterations that would be possible by a person skilled in the art in accordance with the entire disclosure, including the claims and drawings, and the technical concept thereof. Furthermore, with regard to the numerical values ​​and numerical ranges described in this application, any intermediate values, lower values, and smaller ranges are deemed to be included, even if not explicitly stated. Furthermore, the disclosures of the above-cited documents, when used in part or in whole in combination with the disclosures herein as part of the disclosure of the present invention, in accordance with the spirit of the present invention, are also deemed to be included in (belong to) the disclosures of this application. [Explanation of symbols]

[0032] 10 Shielding parts 11 Metal plate 11a Base metal plate 11b plating layer 12 Hydrophilic Block 13 Molding section R1 area

Claims

1. a metal plate having a plating layer on a base metal plate; a plurality of hydrophilic blocks arranged in a dot pattern on the plating layer at arbitrary or predetermined intervals; Equipped with the surface area per unit volume of the hydrophilic block is greater than the surface area per unit volume of the plating layer; Shield parts.

2. The shielding component according to claim 1 , wherein the wettability of the lead-free solder to the hydrophilic block is higher than the wettability of the lead-free solder to the plating layer.

3. 2. The shielding component according to claim 1, wherein the base metal plate is a stainless steel plate, an aluminum plate, a brass plate, a nickel silver plate, or a tin plate.

4. 2. The shielding component according to claim 1, wherein the plating layer is made of Ni, Zn, Cu, Al, Sn, or a combination of two or more of these.

5. The shielding component according to claim 1 , wherein the hydrophilic block is made of an ultraviolet curable resin.

6. The shielding component according to claim 1 , wherein the surface of the hydrophilic block is an uneven surface having a plurality of recesses or protrusions.

7. a printed wiring board having a conductor pattern; an electronic component mounted on the printed wiring board; a shielding component according to any one of claims 1 to 6, which is disposed so as to cover the electronic component and is fixed to the conductor pattern of the printed wiring board by lead-free solder; An electronic device comprising:

8. forming a plating layer on a base metal sheet; forming a plurality of hydrophilic blocks in a dot pattern on the plating layer at arbitrary or predetermined intervals; Including, the surface area per unit volume of the hydrophilic block is greater than the surface area per unit volume of the plating layer; Manufacturing method of shielding parts.

9. In the step of forming the plurality of hydrophilic blocks, the plurality of hydrophilic blocks are formed so that the surfaces of the hydrophilic blocks have an uneven surface having a plurality of recesses or protrusions. The method for manufacturing the shielding component according to claim 8.

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