JP2011129845A - Electromagnetic wave shield using electroforming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce and provide an electromagnetic wave shield that has precision of micron order of boring of a small hole inexpensively by electroforming. <P>SOLUTION: The electromagnetic wave shield 1 is made of metal, and alloy thereof can be freely selected as long as it can be manufactured by electroforming. A solid which is a cube, a column, a sphere, or a combination thereof can be selected as the whole shape. A hole 2 for heat dissipation may be round, square, rhombic, polygonal, etc. A size of the hole may be freely selected as long as an electromagnetic wave does not leak. One surface of the solid is open, and a generation source for an electromagnetic wave and an electronic component which is vulnerable to the electronic wave can be covered. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a precision small metal electromagnetic wave shield using an electroforming method.

  Along with the development of electronic devices, more devices generate electromagnetic waves. In the future, with the increase of electronic information, more and more devices are modulated with high frequency, and more electromagnetic waves are expected to be generated. Electromagnetic waves not only affect a single machine such as a pacemaker, but electromagnetic waves generated in a part of the device may affect circuits in the same device, so it is necessary to block them.

  For example, tin and aluminum cases have been used for the tuners of CRT televisions to prevent electromagnetic waves. For large-sized TVs, a large press shield could be used, but now everything is integrated. For example, in flat-screen TVs, mobile phones, and optical communication devices, the distance between parts is very narrow. In addition, partial electromagnetic shielding of several hundred microns has become necessary.

  For example, FIG. 4 shows a tuner portion of a television set produced by a press. The electromagnetic wave shield of the press is suitable for manufacturing a large amount of standard products, but it is small to shield a part of the printed circuit board, integrated circuit, and semiconductor element from the electromagnetic wave, and it is difficult to produce a variety of products. It is. In addition, if the production is performed in units of microns, a precise mold is required, and the production cost is high, thus increasing the product price. In addition, the press retains the stress when bent, and there is a concern about thermal deformation due to heat radiation from the electronic components. Shielding without gaps not only hinders the heat dissipation effect, but also keeps heat, so it is preferable to make fine holes in the shield, but fine holes can be made not only by conventional press technology but also by fine etching method It is difficult to make a large number of holes for heat dissipation with micron precision. Accordingly, an object of the present invention is to inexpensively produce and provide a metal electromagnetic wave shield having micron unit accuracy with a small hole by electroforming.

  In order to solve the above-mentioned problems, the first invention is an electromagnetic wave shield in which a metal is grown on a male resist by electroforming as shown in FIG. is there. Since the electroforming method grows at room temperature or at a low temperature of less than 50 degrees, there is almost no thermal deformation. Regarding the coefficient of thermal expansion, the coefficient of thermal expansion can be matched to the substrate to be bonded by changing the growth speed at the stage of metal growth. Regarding the hole for heat dissipation, if there is no hole, it is closed by a shield and the heat from the heating element is reflected by the metal surface, resulting in a higher temperature than if it is not shielded and damaging the semiconductor. Heat dissipation is as important as the prevention of electromagnetic waves in electronic parts, and electromagnetic shields must also consider countermeasures with an emphasis on heat dissipation performance. However, the smaller the size of the electromagnetic wave shield, the smaller the holes for heat dissipation, making it difficult to make holes uniformly without gaps. For example, when a hole is made by an etching method, it is usually not possible to make it less than the thickness of the metal. For example, if the thickness of the shield material is 200 microns, the diameter of the hole becomes as large as 200 microns, and many holes cannot be formed in the shield. In the case of electroforming, the hole diameter can be reduced regardless of the thickness of the metal. The technique of drilling small holes by electroforming has been demonstrated with inkjet printer nozzles and nebulizers. Furthermore, the electroforming method can easily make the shape of the shield cubic or cylindrical, or a solid that combines them, and can accurately manufacture the inner dimensions of the electromagnetic shield, and is weak against electromagnetic sources and electromagnetic waves. Electronic parts can be covered with good heat dissipation within the minimum necessary range.

  In the second invention, when an electromagnetic shield manufactured by electroforming is attached to a substrate or an integrated circuit, solder 7 is used as shown in FIG. 3, and a metal having excellent adhesion by solder 7 is used as a shielding material. It is characterized by things. Examples of the metal include boron nickel, copper, and copper surface treatment with gold. In the case of nickel alone, when a problem of repelling solder occurs due to nickel surface oxidation, an alloy containing, for example, 1 to 2% of boron is suitable for preventing surface oxidation. Since copper has good heat dissipation characteristics, it can be used as a shield for parts that generate heat, and if gold is surface-treated, oxidation after installation can be prevented. In processes such as printed circuit boards, there is a soldering process for mounting chip resistors and chip capacitors, making it easier and faster to bond than using adhesives such as silver epoxy, and cost reduction is possible with high productivity.

  In the third invention, in order to make the electromagnetic wave shield movable by a vacuum chuck often used in a semiconductor assembling apparatus, an area 3 in which a hole is not formed for an air chuck is provided on a part of the upper surface of the electromagnetic wave shield. The areas are shown in FIGS.

  According to the first invention, the second invention, and the third invention, only a small part on the printed circuit board or flexible substrate is shielded from electromagnetic waves, or only the light receiving part of the light receiving element used in optical communication is opened. Thus, it is possible to install a minute shield such as a shield covering, a part of an integrated circuit such as an LSI, a CPU, etc., accurately and inexpensively even with an accuracy of a micron. Further, the attachment by soldering is connected to the ground, which is preferable in terms of circuit.

1 is a perspective view of an electromagnetic wave shield having a long side of about 6 mm and covering an LSI according to an embodiment of the present invention. FIG. 2 is a perspective view of an electromagnetic wave shield having a long side of about 4 mm in a shape installed inside an LSI resin mold showing an embodiment of the present invention. 1 is a perspective view of an electromagnetic wave shield having a long side of about 1 mm and covering a light receiving element according to an embodiment of the present invention. It is a top view which shows the television tuner of the press by a prior art. It is a top view which shows the electromagnetic wave shield cross section of the electroforming method by a male resist.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 3 and an explanation of electroforming shown in FIG. 5. The position, size, etc. of each part are described in the description of the present invention. The material and numerical conditions, and the object to be shielded are merely examples, and the present invention is not limited to the following embodiments.

  The electromagnetic wave shield 1 of FIG. 1 manufactured by electroforming is made of metal, and its alloy can be freely selected as long as it is within a range that can be manufactured by electroforming. The entire shape can be selected from simple cubes, cylinders, spheres, and solid combinations of them. The shape of the heat radiating hole 2 can be selected from a circle, a square, a diamond, and a polygon. The size of the hole can be selected within a range where electromagnetic waves do not leak. One surface of the three-dimensional object is open and can cover an electromagnetic wave generation source and an electronic component that is weak against the electromagnetic wave.

  FIG. 5 is a sectional plan view showing the relationship between the male resist 8 and the electroformed electromagnetic wave shield 1. Although it is possible to grow a metal on a female resist, in that case, the dimensional accuracy of the outer surface of the shield is accurate, but the inner dimensional accuracy is not accurate. When the minimum electromagnetic shielding is required in a limited installation space, if the dimensional accuracy at the distance between the object to be shielded and the shield inner surface is accurate, the distance can be reduced with confidence, so the smallest electromagnetic shielding is produced. be able to. Therefore, the male resist 8 having good dimensional accuracy of the shield inner surface 10 is preferable. The object to be shielded is both an electric component that generates an electromagnetic wave and an electric component that is easily affected by the electromagnetic wave, and is not limited to one.

  FIG. 1 is a perspective view of an electromagnetic wave shield having a long side of about 6 mm in a shape covering the LSI 5. For example, a large number of holes 2 for heat dissipation are formed in the upper part of the electromagnetic wave shield manufactured by the method of FIG. As long as the hole 2 has a size that does not leak electromagnetic waves, the shape and size are not defined. There is a portion 3 having no hole in a part of the upper part of the electromagnetic wave shield 1, which is a suction point for a vacuum chuck. It has been devised to prevent the vacuum chuck from being able to inhale if there is a hole. The electromagnetic wave shield is mounted with an LSI on a substrate, then loaded with a vacuum chuck or a collet chuck, and soldered.

  FIG. 2 is a perspective view of an electromagnetic wave shield having a long side of about 4 mm in a shape installed inside the resin mold of the LSI 5. Although the shape and method are similar to those in FIG. 1, the difference is the shape that does not cover the outside of the LSI 5 but is set before resin molding in the LSI manufacturing process. Resin molding is performed after the installation of the electromagnetic shield, and it looks like an ordinary LSI, but it is an electromagnetic shielding product.

  FIG. 3 is a perspective view of an electromagnetic wave shield having a shape covering the light receiving element 6 and having a long side of about 1 mm. It is a very small electromagnetic shield, and it is difficult to make the small hole 2 by the etching method. In addition, when the inside of the electromagnetic wave shield is eroded by etching, the four corner portions are R-shaped instead of corners. Since the radius is about 80% of the thickness of the metal, if the thickness of the electromagnetic shield is assumed to be 100 microns, the radius will be 80 microns, and parts cannot be placed on the circle, and the entire electromagnetic shield becomes larger. End up. The four corners produced by electroforming are right-angled, and the accuracy can be even less than 2 microns, so that the gap between the parts can be reduced. Also, the light receiving opening 4 can be accurately manufactured. The electromagnetic wave shield moves in the same way as the chip capacitor is handled by the assembly robot, and is fixed by soldering 7. Although FIG. 3 shows an example of shielding an electromagnetic wave from the outside to the light receiving element, a shield that covers the light emitting element and does not emit the electromagnetic wave emitted by the light emitting element to the outside can be performed in exactly the same manner.

"Effect of the embodiment"
According to this embodiment, it is possible to selectively shield a minute part in the millimeter or micron unit according to its shape. Of course, conventional large parts can also be shielded. By making a hole in the shield, heat dissipation effect, light weight, and resource saving can be done at the same time. Furthermore, since it can be attached by soldering, the current manufacturing process can be used as it is in the procedure of installing a chip capacitor without any special process.

"Other embodiments"
In the embodiment of FIG. 2, the entire inside of the resin mold is covered, but a part of the circuit can be covered instead of the whole. The minute electromagnetic wave shield as shown in FIG. 3 can also be used inside the can package.

DESCRIPTION OF SYMBOLS 1 Electromagnetic wave shield 2 Radiation hole 3 Vacuum chuck area 4 Opening part 5 LSI 6 Light receiving element 7 Solder 8 Male resist 9 Substrate 10 Shield inner surface

Claims (6)

  Electromagnetic wave shield manufactured by electroforming, characterized by covering a metal cube with a fine hole or a cylindrical shape or an assembly thereof with an electromagnetic wave generation source or an electronic component vulnerable to the electromagnetic wave.   Three-dimensional shields with fine holes are suitable for soldering, for example, produced by electroforming with metals such as boron nickel and copper, and can be easily soldered to substrates and LSIs in the production lines for ordinary semiconductors and electronic components. Metal electromagnetic shield that can be attached with   Small metal electromagnetic wave shield using an electroforming method that can be shielded in micron units by selecting only the part or source that is susceptible to electromagnetic waves as a pinpoint.   Electronic components for electromagnetic wave countermeasures that have been commercialized by attaching small metal electromagnetic shields using electroforming to LSIs, CPUs, and diodes in can packages.   Small metal electromagnetic wave shield using the electroforming method that can accurately control the size system of the inner surface of the shield and fine holes in micron units by taking advantage of the characteristics of the electroforming method in which metal grows along the resist   In order to be able to move the shield with an air chuck in the production line, a metal electromagnetic wave shield by electroforming with an area not drilled on a part of the upper surface

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