JP2012178408A - Shield structure of integrated circuit - Google Patents

Abstract

Provided is a shield structure for an integrated circuit, which can suppress the restriction of the degree of freedom of substrate design and the restriction of the substrate area, and can protect the substrate and improve the shielding performance.
A shield member includes a side wall portion that contacts a protective film portion of a substrate, a concave portion provided in the side wall portion, a facing portion that faces the ground portion in a state of being separated from the ground portion of the substrate, An electrically conductive member is provided to fill an empty space between the facing portion and the ground portion.
[Selection] Figure 1

Description

  The present invention relates to a shield structure for an integrated circuit that protects an integrated circuit and has improved shielding properties for shielding electromagnetic waves generated from the integrated circuit.

  Conventionally, in order to prevent scratches on a substrate on which an integrated circuit is mounted, a protective film is formed by performing silk screen printing on the peripheral portion of the substrate on which the integrated circuit is mounted or on the substrate surface that comes in contact with the substrate support portion. It has been known.

  In Patent Document 1, it is disclosed that silk screen printing is performed on a peripheral portion of a substrate on which an integrated circuit is mounted in order to prevent generation of scratches when supported by a support portion of a manufacturing apparatus. Japanese Patent Application Laid-Open No. H10-228561 discloses that the damage to the integrated circuit is prevented by performing silk screen printing on the surface of the substrate that comes into contact with the supporting portion that holds the substrate.

JP-A-8-125288 JP 2001-298256 A

  However, in the above-described prior art, no mention is made of shielding properties for shielding electromagnetic waves generated from an integrated circuit. When the integrated circuit is shielded, silk screen printing is performed on the support portion so that the substrate is not damaged. On the contrary, the continuity cannot be obtained and the shielding effect may be impaired. Further, if a gap is not formed between the board and the shield member, restrictions on the board design occur.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a shield structure for an integrated circuit capable of protecting the substrate and improving the shielding performance.

In order to achieve the above object, an invention according to the present application is configured to shield an integrated circuit arrangement portion on a substrate on which an integrated circuit is mounted from an integrated circuit arrangement portion in a box shape having an open side of the integrated circuit arrangement portion, and generating electromagnetic waves from the integrated circuit. In the shield structure of the integrated circuit covered by the shield member,
The integrated circuit arrangement portion includes a ground portion having a zero potential, and a protective film portion in which a protective film is formed in at least a part of the region excluding the ground portion, and the shield member includes A side wall part that contacts the protective film part, a concave part provided in the side wall part, and a counter part that faces the ground part in a state of being separated from the ground part, and the counter part and the ground part An electrical conducting member is provided to fill the gap.

  According to the present invention, it is possible to suppress the restriction of the degree of freedom of the substrate design and the restriction of the substrate area, protect the integrated circuit, and improve the shielding property.

It is a block diagram before the whole assembly of the shield structure of the integrated circuit concerning the 1st Embodiment of this invention. It is a completion drawing after the whole first embodiment is incorporated. It is a general-view figure of a shield member. It is a detailed enlarged view regarding the side wall part of a shield member. It is explanatory drawing of the board | substrate which mounts an integrated circuit. It is a detailed enlarged view of the ground portion of the substrate. It is a detailed enlarged view which shows the contact state of the protection part of a board | substrate, and the side wall part of a shield member. It is a detailed enlarged view of the state where the ground portion of the substrate and the facing portion of the shield member are filled with the electrically conductive member. It is a whole block diagram in the case of cooling by using a heat conduction sheet and conducting heat generation of an integrated circuit by heat conduction of a shield member. It is a figure which shows the shielding member concerning 2nd Embodiment. It is a completion figure after whole incorporation in 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<< First Embodiment >>
Hereinafter, the overall configuration of the shield structure of the integrated circuit (IC) according to the present embodiment will be described with reference to FIGS. FIG. 1 is an overall configuration diagram before the IC shield structure is assembled, and FIG. 2 is a completed diagram after the entire IC shield structure is assembled. The basic structure of the IC shield structure 1000 is composed of a substrate 10 having an integrated circuit arrangement portion 80 and a shield member 20 that is a sheet metal that shields electromagnetic waves generated from the integrated circuit in a box shape with the integrated circuit arrangement portion side open. Is done.

(Substrate having an integrated circuit arrangement portion)
The integrated circuit placement unit 80 includes an IC 30 mounted on a substrate, a ground portion (GND portion) 40 that is provided in a predetermined partial region of the surface layer of the substrate 10 and has an electric potential of zero, and a silk screen on the substrate. And a printed protective film 50. The protective film 50 has at least a part of the region excluding the ground portion 40 (only the edge where a side wall of a shield member described later contacts, or the inside surrounded by the edge in addition to this edge. Alternatively, a protective film portion is formed at a peripheral portion. Generally, the protective film 50 is further provided in a region excluding the integrated circuit, but the integrated circuit may be protected by an upper protective film. The protective film portion on which the protective film 50 is formed is configured such that a side wall portion of a shield member 20 described later is in contact with the protective film portion and a gap (opening) is not formed.

  Next, the detailed structure will be described. FIG. 5 is an overall view of the substrate 10, and FIG. 6 is a detailed enlarged view of the ground portion 40 and the protective film 50 in a broken line frame B in FIG. An IC 30 is mounted on the substrate 10 and a ground portion 40 is formed in the vicinity thereof. In FIG. 6, silk screen printing is performed with a width of 0.5 mm and a thickness of 30 μm in the same shape as the edge of phosphor bronze that is the shield member 20 with the protective film 50 sandwiching the ground portion 40 in the longitudinal direction of the edge. It is given in. Although the silk screen printing is not applied to the ground portion 40, the silk screen printing is also applied to the periphery or the peripheral portion of the IC 30 in addition to the edge portion.

  The protective film is made of an epoxy-based resin, and a manufacturing method other than silk screen printing may be used for forming the protective film. In addition, the edge part which consists of a protective film silkscreen-printed also serves as the display part which shows the position of the shield member 20 at the time of shield structure assembly.

(Shield member)
The shield member 20 attached so as to cover the IC 30 is formed as a first contact portion 21 as a facing portion that is finally brought into conduction with the ground portion 40 of the substrate, and a side wall portion in contact with the protective film 50 printed with silk screen. The second contact portion 22 is provided. As shown in FIG. 3, the shield member 20 has a box shape (a bowl shape) in which four sides of a sheet metal are bent to cover the IC 30. The 1st contact part 21 and the 2nd contact part 22 are formed in the edge part of a bending process. 4 is a detailed enlarged view of the first contact portion 21 and the second contact portion 22 in the broken line frame A in FIG.

  As for the side walls of the four sides of the shield member 20, as shown in FIG. 4, the second contact portion 22 is formed longer than the first contact portion 21 than the bending position at the time of four-side bending. That is, in FIG. 4, the height L from the upper surface of the shield member 20 to the lower surface of the first contact portion 21 is set lower than the height M from the upper surface of the shield member 20 to the lower surface of the second contact portion 22. ing.

  The first contact portion 21, which is the facing portion of the ground portion 40, is in a concave portion (region including empty spaces S 0, S 1, S 2) on the side wall portion and faces the ground portion 40 in a state of being separated from the ground portion 40. . Although the vacant space S0 will be described later, it is filled with an electrically conductive member, and the vacant space S0 disappears afterwards. The empty spaces S1 and S2 in FIG. 4 may be filled with a member other than the electrically conductive member in addition to being filled with the electrically conductive member. If the empty spaces S1 and S2 are small spaces, the empty spaces S1 and S2 can be used without being filled.

  The shield member 20 in this embodiment uses a phosphor bronze plate so that bending can be performed on the four sides of the shield member, but other materials may be used as long as they are conductive members.

(Shields other than empty space S0)
7 shows a detailed enlarged view and a cross-sectional view of the substrate 10, the first contact portion 21, and the second contact portion 22 with respect to C in the broken line frame in FIG. 2. The shield member 120 is attached so as to cover the IC 30, and the silk screen in which the second contact portion 122 is the protective film 50 before the first contact portion 121 of the shield member 120 and the ground portion 40 come into contact with each other. Contact printing.

  Regarding the electromagnetic field shield, there is a risk that the size of the gap (slit) (long side of the rectangle) is an efficient slit antenna at a frequency of a wavelength that is an integral multiple of λ / 4. However, as shown in FIG. 7, with the above-described configuration, the substrate 10 and the shield member 20 are in contact with each other at a portion other than the ground portion 40, and the slit portion that is concerned about the shield structure corresponds to the substrate GND portion 40. The area can only be reduced. In other words, the shielding property is secured by first contacting the side wall portion of the shield member and the protective film portion of the substrate outside the empty space S0.

(Shield in empty space S0)
The shield member 20 is preferably connected to the ground portion (GND portion) 40 of the substrate. With respect to the region corresponding to the ground portion 40, the ground portion 40 and the facing portion are electrically connected via the electrically conductive member. For example, as shown in FIG. 8, the empty space S <b> 0 that is a gap between the ground portion 40 and the first contact portion 21 as the opposing portion is filled with the solder 60. A gasket may be used in place of the solder 60 as an electrically conductive member that fills the empty space S0. As a result, the shielding effect is improved, and formation of the long side slit that may become the slit antenna described above can be suppressed.

  In addition, the ground part 40 in a board | substrate and the 1st contact part 21 as an opposing part in a shield member are each provided 4 pieces corresponding to four side wall parts equivalent to 4 sides, and the ground part 40 and 1st The contact portions 21 are electrically connected to each other via an electrically conductive member. The ground portion 40 on the substrate and the first contact portion 21 as the opposing portion on the shield member may be provided one, two, or three without providing four, respectively.

(Cooling integrated circuits)
In the case of the present embodiment, since the IC 30 is covered with the shield member 20, it is difficult to cool the IC 30. Therefore, as shown in FIG. 9, a heat conductive sheet 70 having a high contractibility is sandwiched between the back surface of the upper surface of the shield member 20 and the IC 30, and the heat generated by the IC 30 is transferred to phosphor bronze which is the shield member 20. It is structured to conduct heat and cool.

  As described above, according to the present embodiment, by using the above-described structure, substrate damage due to the shield member 20 and disconnection of signal lines in the transportation environment and usage conditions can be prevented by silk screen printing which is the protective film 50. In addition, in the high-density design substrate, the facing portion 21 that faces the ground portion 40 can be a small region by using the concave portion provided in the side wall portion. In other words, forming the ground portion in the same shape over the entire outer periphery of the edge of the shield member 20 reduces the degree of freedom in designing the substrate, whereas this embodiment ensures the degree of freedom in design. Therefore, it is possible to design a reduced substrate that does not require a large space.

<< Second Embodiment >>
Hereinafter, the shape of the shield member 120 according to the present embodiment will be described with reference to FIG. FIG. 11 is an overall view of an IC shield structure 2000 in which a shield member 120 is incorporated. Except for the configuration related to the shield member 120 of the present embodiment, the structure is basically the same as that of the first embodiment.

  The shield member 120 of the present embodiment is formed by drawing a sheet metal, and a first contact portion 121 and a second contact portion 122 are provided at the edge portion. When the sheet metal is formed by drawing, it is difficult to form slit openings in the four corner regions C in the region serving as the boundary between the upper surface and the side wall, and the shielding property can be improved. As in the first embodiment, the shield member 120 is attached so as to cover the IC 30, and the second contact portion 122 is protected before the contact between the first contact portion 121 and the ground portion 40 of the shield member 120. The silk screen printing which is the film 50 is contacted.

  The shield member 120 is preferably connected to the ground (GND) of the substrate so as to have an electrical potential of zero, and is electrically connected to the ground portion 40, so that the ground portion 40 and the first contact portion 121 are connected by solder or gasket. And fill the gap. As a result, the gap between the sheet metals generated by the sheet metal bending process can be filled, and the shielding property is improved. This embodiment uses sheet metal drawing, but can be changed within the scope of the gist, and the shape of the shield member 120 may be created by molding with a conductive material.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

10 .. Substrate, 20 .. Shield member, 21 .. First contact part (opposite part), 22 .. Second contact part (side wall part), 30 .. Integrated circuit, 40 .. Ground part (GND) Part), 50 ... protective film part, 60 ... solder (electrically conductive member), 70 ... heat conductive sheet, 80 ... integrated circuit placement part, 1000 ... shield structure

Claims (4)

In the shield structure of the integrated circuit, the integrated circuit arrangement portion on the substrate on which the integrated circuit is mounted is a box shape with the integrated circuit arrangement portion side opened and covered with a shield member that shields electromagnetic waves generated from the integrated circuit.
The integrated circuit arrangement portion includes a ground portion having a zero potential, and a protective film portion in which a protective film is formed in at least a part of the region excluding the ground portion,
The shield member has a side wall part that contacts the protective film part, a concave part provided in the side wall part, and a facing part that faces the ground part in a state of being separated from the ground part,
A shield structure for an integrated circuit, comprising: an electrically conductive member that fills a space between the facing portion and the ground portion.   The shield structure for an integrated circuit according to claim 1, further comprising: a heat conductive sheet for transmitting heat of the integrated circuit to the shield member.   3. The integrated circuit shield structure according to claim 1, wherein the ground portion and the facing portion are provided on all side wall portions of the shield member, respectively.   4. The shield structure for an integrated circuit according to claim 1, wherein the shield member is made of a sheet metal formed by drawing.