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

Abstract

The present invention provides a shielding part and the like that can contribute to stabilizing the bond between a plating layer of the shielding part and lead-free solder. [Solution] The shielding part 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 any or predetermined intervals, the hydrophilic blocks may be made of ultraviolet-curing resin, and the surface of the hydrophilic blocks may be an uneven surface having a plurality of recesses or protrusions.

Description

[Technical field]

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

[0002] Some printed wiring boards mounted on electronic devices are equipped with shielding parts (shielding covers, shielding cases, etc.) that are arranged to cover electronic components mounted on the printed wiring board to protect the electronic components mounted on the printed wiring board from the effects of electromagnetic waves and radiation. The shielding parts are fixed to the conductor pattern of the printed wiring board by solder and electrically connected to the earth. As for solder, the use of lead solder has been restricted due to environmental conservation efforts, and lead-free solder has come to be used. Compared to lead solder, lead-free solder has the property of being less likely to wet and spread on the conductor pattern due to differences in surface tension, interfacial tension, formation of a stable oxide film, electrochemical factors (electrode potential), etc. If it is difficult to wet and spread, defects such as solder joints not being formed are likely to occur. If solder joints are not formed, the shielding effect and the adhesive strength of the shielding parts to the board are reduced, making the product unsuitable. For this reason, it is desirable for lead-free solder to wet and spread (reducing the contact angle) not only on the conductor pattern but also on the shielding parts.

[0003] As an example of a method for allowing lead-free solder to wet and spread over 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 part of Patent Document 1, the entire surface of the shielding part is covered with a plated layer, and the thickness of the plated layer is not constant due to unevenness. Therefore, during the manufacturing process of the shielding part, the plated layer may be altered, chipped, or thin 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 shielded component, an electronic device, and a method for manufacturing a shielded component that can contribute to stabilizing the bond between the plating layer of the shielded 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.

[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 arranged to cover the electronic component and fixed to the conductor pattern of the printed wiring board by lead-free solder.

[0010] A manufacturing method for 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 any or predetermined intervals. Effect 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 description of the drawings]

[0012] [Figure 1] 1 is a perspective view showing a schematic example of a configuration of a shield component according to the present disclosure. FIG. [Diagram 2] 1A is a plan view showing a schematic diagram of a first example of the configuration of a shield component according to the present disclosure, and FIG. 1B is an enlarged plan view of a region R1. [Diagram 3] 2(B) is a cross-sectional view taken along line XX' in FIG. 2(B) that illustrates a first example of the configuration of a shielding component according to the present disclosure. [Figure 4] 1A is a perspective view showing 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′. [Diagram 5] 1A to 1C are partial cross-sectional views illustrating process steps of a manufacturing method for a shield component according to the present disclosure. [Figure 6] 11 is a partial cross-sectional view that illustrates a second example of the configuration of a shield component according to the present disclosure. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments will be described with reference to the drawings. Note that when reference symbols are used in this application, they are intended to aid understanding only and are not intended to limit the present invention to the illustrated embodiments. In addition, 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 that shows a schematic example of the configuration of the shielding component according to the present disclosure. FIG. 2 is a plan view (A) that shows a schematic first example of the configuration of the shielding component according to the present disclosure, and an enlarged plan view (B) of a region R1. FIG. 3 is a cross-sectional view taken along line X-X' in FIG. 2(B) that shows a schematic first example of the configuration of the shielding component according to the present disclosure. FIG. 4 is a perspective view (A) that shows a schematic first example of the configuration of the hydrophilic block of the shielding component according to the present disclosure, and a cross-sectional view (B) of 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 on an electronic device (e.g., a communication device, a power supply device, etc.) in order 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) of the printed wiring board (not shown) by solder (not shown) and electrically connected to a ground. The shielding component 10 is configured such that a plurality of hydrophilic blocks 12 are arranged in a dot shape (polka dot shape) at arbitrary or predetermined intervals on the surface of a metal plate 11 (plating layer 11b) so as 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, and may be molded into a cover shape by folding at a molding portion 13 as shown in FIG. 1, or into a box shape.

[0016] The metal plate 11 is a plate-shaped member having a plating layer 11b on a base metal plate 11a (see Figs. 1 to 3). For example, a stainless steel plate, an aluminum plate, a brass plate, a nickel silver plate, a tin plate, etc. can be used for the base metal plate 11a. For example, a metal plating that easily wets and spreads lead-free solder can be used for the plating layer 11b, such as Ni, Zn, Cu, Al, Sn, etc., or a combination of two or more of these. For example, Sn-Zn-based, Sn-Ag-based, Sn-Ag-Cu-based, Sn-Bi-based, Sn-Zn-Bi-based, Sn-Cu-based, Sn-Ag-In-Bi-based, Sn-Zn-Al-based lead-free solder can be used as the lead-free solder. Here, among the factors affecting the wettability of solder, when 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 present inventors have discovered that if the surface area of ​​plating layer 11b is increased by subjecting it to thermal processing, chemical processing (corrosion), or physical processing, it becomes difficult for a solder bond to be formed between the lead-free solder and plating layer 11b.

[0017] The hydrophilic block 12 is a block having hydrophilicity (see Figs. 1 to 4). The hydrophilicity of the hydrophilic block 12 is higher than that of the plating layer 11b. The hydrophilic block 12 is made of a hydrophilic material, for example, an ultraviolet curing resin, and may be an ultraviolet curing acrylic resin, an ultraviolet curing urethane resin, or the like. The wettability of the lead-free solder to the hydrophilic block 12 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 and a conical surface) having a plurality of fine concaves or convexities (see Fig. 4(B)). The shape and arrangement of the concaves on the uneven surface are arbitrary. The hydrophilic blocks 12 are arranged in a dot pattern (polka dot pattern) on the surface of the metal plate 11 at arbitrary or predetermined intervals so as not to overlap. This makes it possible to increase the surface area of ​​the shielding component 10 including the hydrophilic blocks 12, reduce the contact angle, and improve the wettability of the solder while exposing the surface (plating layer 11b) of the metal plate 11 required for solder bonding, without damaging the surface of the metal plate 11. The shape (planar shape) of the hydrophilic blocks 12 is arbitrary and is not limited to a rectangle (square), but may be a circle, a triangle, or another shape. The arrangement of the hydrophilic blocks 12 is also arbitrary.

[0018] Next, a method for producing the shielding component according to embodiment 1 will be described with reference to the drawings. Fig. 5 is a partial cross-sectional view showing a process for the method for producing the 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, a plurality of hydrophilic blocks 12 are formed in dots (or polka dots) on the metal plate 11 (on the plating layer 11b) at arbitrary or predetermined intervals (see FIG. 5(C)). The hydrophilic blocks 12 can be formed, for example, by using a photo-imprinting method, that is, by applying a liquid ultraviolet-curing resin onto the plating layer 11b, pressing a transparent mold onto the ultraviolet-curing resin, and photo-curing the ultraviolet-curing resin by irradiating it with ultraviolet light. During printing, the hydrophilic blocks 12 are printed at regular intervals while exposing the surface (plating layer 11b) of the metal plate 11 to be solder-joined. Also, it is possible to form an uneven surface on the surface of the hydrophilic block 12. By forming the uneven surface, the surface area increases and the contact angle decreases, making it easier for the lead-free solder to wet and spread 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 tends to wet and spread on 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 embodiment 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 deterioration, chipping, or thinning of the plating layer 11b is prevented, 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, so that the lead-free solder can be fused with the plating layer 11b to ensure solder bonding while improving the wettability of the lead-free solder on the surface of the shielding component 10.

[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 that illustrates 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 metal base 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, and the contact angle of the lead-free solder on the surface of the shielding component 10 can be reduced, thereby 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 follows, but are not limited to the following:

[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 part comprising: [Appendix 2] 2. The shielding component of claim 1, wherein the hydrophilic block has a higher wettability with the lead-free solder than the plating layer. [Appendix 3] 3. The shielding component according to claim 1 or 2, 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 claim 1, wherein the base metal plate is a stainless steel plate, an aluminum plate, a brass plate, a nickel silver plate, or a tinplate 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 claim 1, 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 shape on the plating layer at arbitrary or predetermined intervals; A method for manufacturing a shielding part, 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 rays are irradiated to photo-cure the ultraviolet curing resin, thereby forming the plurality of hydrophilic blocks. A method for manufacturing the 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 surface of each of the hydrophilic blocks has an uneven surface having a plurality of recesses or protrusions. 12. A method for manufacturing a shielding part according to claim 10 or 11. [Appendix 13] a step of press-molding 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 claims 10 to 12.

[0031] The disclosures of the above patent documents are incorporated herein by reference and may be used as the basis or part of the present invention as necessary. Within the framework of the entire disclosure of the present invention (including the claims and drawings), modifications and adjustments of the forms and embodiments are possible based on the basic technical ideas. Furthermore, within the framework of the entire disclosure of the present invention, various combinations or selections (or non-selection as necessary) of various disclosed elements (including each element of each claim, each element of each form or embodiment, each element of each drawing, etc.) are possible. In other words, the present invention naturally includes various modifications and corrections that a person skilled in the art would be able to make in accordance with the entire disclosure, including the claims and drawings, and the technical ideas. Furthermore, with regard to the numerical values ​​and numerical ranges described in this application, any intermediate value, lower numerical value, and small range are considered to be described even if not specified. Furthermore, the disclosures of the above cited documents may be used in part or in whole in combination with the descriptions in this document as part of the disclosure of the present invention in accordance with the spirit of the present invention as necessary, and are considered to be included (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 wettability of the lead-free solder to the hydrophilic block is higher than the wettability of the lead-free solder to the plating layer; Shield parts.

2. 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.

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

4. 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 shield 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; 7. The shielding part according to claim 1, which is disposed so as to cover the electronic component and is fixed to the conductor pattern of the printed wiring board by a 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 shape on the plating layer at arbitrary or predetermined intervals; Including, 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; 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 surface of each of the hydrophilic blocks has an uneven surface having a plurality of recesses or protrusions. The method for manufacturing the shielding part according to claim 8.

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