WO2007029355A1

WO2007029355A1 - Shield structure

Info

Publication number: WO2007029355A1
Application number: PCT/JP2006/300144
Authority: WO
Inventors: Shingo Komura; Tetsuro Tabata; Masato Koyama
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2005-09-01
Filing date: 2006-01-10
Publication date: 2007-03-15
Also published as: JP4527035B2; JP2007067279A

Abstract

Disclosed is a shield structure of an electronic device comprising a printed wiring board (12) having a circuit chip (22) and a shield frame (31) surrounding the circuit chip (22) in the same plane, and a printed wiring board (11) on which a copper foil pattern (33) for shield is formed. This shield structure is constituted so that the opening portion of the shield frame (31) of the printed wiring board (12) comes into contact with the copper foil pattern (33) of the printed wiring board (11) when the printed wiring boards (11) and (12) are assembled.

Description

Specification

Shield structure

Technical field

[0001] The present invention relates to a shield structure for shielding a circuit chip on a printed wiring board.

Background art

Conventionally, circuit chips are separately soldered for each functional block on both sides or one side of one printed wiring board, and characteristic deterioration due to electrical influence between circuit chips of each functional block has occurred. For things that happen, shield them to prevent deterioration of their characteristics.

[0003] As an example, on at least one surface of a printed wiring board, there are a plurality of circuit chips, a shield frame that surrounds these circuit chips, and a shield case that includes a shield cover that closes the shield frame. A circuit board having a shield case, which is reflow soldered, and a manufacturing method thereof are provided (for example, refer to Patent Document 1).

[0004] In the circuit board described in Patent Document 1, the shield case includes a shield frame that surrounds the plurality of circuit chips, and a shield cover force that closes the central opening of the shield frame. There are also cases where the body and the shield cover that closes the central opening of the shield frame are subjected to batch reflow processing.

However, in recent electronic devices, particularly portable devices, downsizing is an important item, and how to embed a printed wiring board and a circuit chip in a limited space is a big problem. Therefore, divide the printed wiring board into multiple printed wiring boards for each function, and stack them in the chassis frame so that the printed wiring boards (including circuit chips and shield cases) do not overlap each other. It is possible.

[0006] For example, consider a case where a second printed wiring board is stacked on a first printed wiring board provided with a shield case. In this case, the thickness from the first printed wiring board to the second printed wiring board is the sum of the following four, resulting in an increase in the thickness of the electronic device. (1) Bottom force of the first printed wiring board Height to the top of the circuit chip mounted on the top surface of the first printed wiring board

(2) Clearance from the top of the circuit chip to the bottom of the shield case top plate

(3) Shield case top plate thickness

(4) Shield case top plate upper surface force Clearance to the bottom surface of the second printed wiring board

[0007] It should be noted that the reason why the above (4) “shield case top plate top surface force gap to the bottom of the second printed wiring board” is necessary is that the second printed wiring board and the shield case top plate are in contact with each other This is to prevent the electrical characteristics from being affected.

Patent Document 1: Japanese Patent Laid-Open No. 10-335869, page 5, FIG. 1

Since the conventional electronic device shield structure has been configured as described above, in order to reduce the size of the electronic device, the printed wiring board is divided into a plurality of printed wiring boards for each function. When stacking in a chassis frame, the thickness of electronic equipment increases.

[0010] The present invention has been made to solve the above-described problems. When the printed wiring boards are stacked and used in the casing, the casing is required for the shield structure of the conventional electronic device. An object of the present invention is to provide a shield structure for an electronic device in which the thickness of the entire electronic device is reduced by reducing the space inside the body.

Disclosure of the invention

[0011] The shield structure according to the present invention includes a first printed wiring board, a circuit chip having a bottom surface attached to the first printed wiring board, and the first printed wiring board. A shield frame that covers the side surface of the chip and surrounds the circuit chip and has an opening provided at a position corresponding to the top surface of the circuit chip, and a shield pattern is formed on the surface facing the top surface of the circuit chip And a second printed wiring board laminated on the first printed wiring board.

[0012] According to the shield structure according to the present invention, even when the printed wiring boards are stacked and used in the housing, the circuit chip can be sufficiently shielded and the thickness of the entire electronic device can be reduced. .

Brief Description of Drawings FIG. 1 is an assembly diagram showing an internal configuration of a mobile phone device to which a shield structure for an electronic device according to Embodiment 1 of the present invention is applied.

FIG. 2 is a cross-sectional view of the printed wiring board 11 in FIG.

3 is a cross-sectional view taken along the line 12a-12b of the printed wiring board 12 in FIG.

4 is a diagram showing a state in which the printed wiring board 11 of FIG. 2 and the printed wiring board 12 of FIG. 3 are connected and further assembled into the chassis frame 51 of FIG.

FIG. 5 is an assembly diagram showing the next stage of FIG. 1.

FIG. 6 is a perspective view showing an internal configuration of a mobile phone device to which a shield structure for an electronic device according to Embodiment 2 of the present invention is applied.

FIG. 7 is a sectional view taken along line l la-l ib of FIG.

FIG. 8 is a cross-sectional view showing an internal configuration of a mobile phone device to which a shield structure for an electronic device according to Embodiment 3 of the present invention is applied.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to describe the present invention in more detail, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1.

Embodiment 1 of the present invention will be described below. FIG. 1 is an assembly diagram showing an internal configuration of a mobile phone to which the shield structure according to Embodiment 1 of the present invention is applied. FIG. 2 is a cross-sectional view taken along line l la-l ib of the printed wiring board 11 in FIG. FIG. 3 is a sectional view of the printed wiring board 12 in FIG. 1 taken along the line 12a-12b. 4 is a diagram showing a state in which the printed wiring board 11 of FIG. 2 and the printed wiring board 12 of FIG. 3 are connected and further assembled into the chassis frame 51 of FIG. FIG. 5 is an assembly diagram illustrating the next stage of FIG. Hereinafter, description will be given with reference to FIGS.

In FIGS. 1 and 2, printed wiring board 11 (second printed wiring board) is an operation unit board, and a dome shape on key switch sheet 4 is formed so as to cover key switch pad 42 on one side. Key switch 41 is arranged.

When a key press switch (not shown) on the operation unit casing is pressed, the key switch 41 is pressed down. The key switch pad 42 has a double ring of copper foil. By lowering, the switch is turned on / off by short-circuiting between the rings. In FIG. 5, on the reverse side of the printed wiring board 11 of FIG. 2, that is, on the opposite side of the key switch sheet 4, the copper foil pattern 33 for shielding, the connector 61 connected to the connector 62 of the printed wiring board 12, and the digital memory Medium 23, audio jack connector 68, RF audio circuit and control circuit (not shown) around audio jack connector 68, connector 66 connected to connector 65 of printed wiring board 13, external connection connector to connect external equipment 6 7 is arranged.

In FIGS. 3 and 5, printed wiring board 12 (first printed wiring board) is a control unit board. On one side, BGA type CPU circuit chip 22, BGA type memory circuit chip 21, and others Circuit chip 2 and a shield frame 31 having a shield structure without a top plate surrounding the circuit chip 2 (attached to the first printed wiring board, covering the side surface of the circuit chip, surrounding the circuit chip, A shield frame) having an opening at a position corresponding to the top surface is disposed. In addition, a connector 62 connected to the connector 61 of the printed wiring board 11 is arranged outside the shield frame 31 !.

A circuit chip 2 is also arranged on the back surface of the printed wiring board 12 and soldered by batch reflow.

[0017] The shield frame here is a plate formed by bending a metal plate into a mass and then cutting out the lower surface. CPU chip and memory chip, etc. have relatively low frequency! Since the digital circuit is mounted on the inside, the gap due to the stagnation of the printed wiring board on the lid side and the unevenness of the shield frame on the lid side Do not affect the shielding effect!

In FIG. 1, the flexible printed wiring board 14 is manufactured in an integrated structure with the printed wiring board 12, and the connector 63 on the flexible printed wiring board 14 is connected to the connector 64 of the printed wiring board 13. As a result, the printed wiring board 12 is also connected to the printed wiring board 13.

In FIG. 1, a printed wiring board 13 is a radio unit board, and transmits / receives a mobile phone by an antenna control RF circuit. On one side, the circuit chip 2 and the connector 65 to be connected to the connector 66 of the printed wiring board 11 are arranged and soldered by batch reflow.

In addition, on the back side, connector 64 connected to connector 63 of flexible printed wiring board 14 Is arranged.

In FIG. 1, the chassis frame 5 is assembled in the direction of the arrow in FIG. 1 in the order of the printed wiring boards 12 and 11 from the front side and then the printed wiring board 13 from the back side. It becomes a structure that can be dredged.

Next, referring to FIGS. 1 to 5, the CPU chip 22, the memory chip 21, and the circuit chip 2 of the printed wiring board 12 are surrounded, and there is no top plate at a position corresponding to the CPU chip 22 and the memory chip 21. Next, the shield structure 31 and the shield structure surrounded by the printed wiring board 11 will be described. The shield frame 31 is soldered to the cream solder application pattern 8 by the solder layer 9, and the cream solder application pattern 8 and the shield cushion pad 53 are applied to the printed wiring board 12 through the through-hole (see FIG. Here, the shield cushion pad 53 and the shield cushion 52 provided on the magnesium chassis frame 51 come into contact with each other to form a shield case shape without a top plate as a whole (Fig. Four).

Further, the shielding copper foil pattern 33 on the opposing printed wiring board 11 is brought into contact with the shield frame 31 of the shield case so as to close the upper surface opening of the shield frame 31 to form a shield structure. The contact is performed by pressing the shield frame 31 on the printed wiring board 12 against the shield copper foil pattern 33 on the printed wiring board 11 using the shield cushion 52 on the chassis frame 51. The shielding frame 31 is formed in a shape in which the top plate facing the shielding copper foil pattern 33 faces the shielding copper foil pattern 33 rather than the horizontal direction. Therefore, the top plate can easily come into contact with the shielding copper foil pattern, and the shielding frame 31 and the shielding copper foil pattern 33 can be reliably conducted with a further restoring force.

In this way, instead of using the shield case top plate, the shield copper foil pattern 33 on the printed wiring board 11 facing the top plate of the CPU chip 22 and the memory chip 21 is used, and instead of the shield case bottom plate. Using the chassis frame 51 facing the lower part of the printed wiring board 12 and further inserting the printed wiring board 13 facing the opposite side of the chassis frame 51, the printed wiring boards 11 to 13 and the shield are connected to each other. Alternately stacked Yes. As a result, the total thickness of the combination of each board is reduced, and the GND potential is joined directly with the shielding copper foil pattern 33, the shield frame 31, the chassis frame 52 on the chassis frame 51, etc. Remove the electrical effects of GND.

[0023] Further, the amount of stagnation of the printed wiring board 11 due to the key press of the key switch 41 is kept small by the rigidity of the shield frame 31, and the stagnation of large parts such as the digital storage medium 23 is regulated. Reduces fatigue of keystrokes in the solder part.

Next, a method for manufacturing the printed wiring board 12 will be described with reference to FIG. The printed wiring board 11 is also installed in the same manner, and assembled into a cellular phone casing (chassis frame 5) after manufacturing.

[0025] The following assembly is performed using a board (hereinafter referred to as a base board) having a cutting margin for assembling the printed wiring board 12.

First, in the first step, on the surface of cream solder coating pattern 8 on one side of the base substrate

The first cream solder pattern that couples the plurality of circuit chips 2 and the second cream solder pattern that joins the shield frame 31 are formed by screen printing or the like. In the second step, the plurality of circuit chips 2 are mounted on the first cream solder pattern, and the shield frame 31 is mounted on the second cream solder pattern.

In the third step, the base substrate on which the multiple circuit chips 2 and the shield frame 31 are mounted is heated in a reflow furnace to perform batch reflow processing.

In the fourth step, an automatic inspection machine is used to check whether there are any wetted parts in the soldered parts.

In the fifth step, the base substrate is turned over and the same process is repeated from the first step to the fourth step. At that time, since the shield frame 31 exists only on one side, the process related to the frame is not performed.

In the sixth step, the cut margin of the finished printed wiring board 12 is cut off and an electrical test is performed using the test pad 7.

Finally, in the 7th step, underfill is applied to the lower part of BGA and other parts in order to make the structure resistant to drop and key press tests.

[0026] As described above, the shield structure according to the first embodiment includes the first printed wiring board (pre- Printed circuit board 12), a circuit chip (CPU chip 22, memory chip 21) with a bottom surface attached to the first printed wiring board, and a side surface of the circuit chip attached to the first printed wiring board. A shielding frame (shield frame 31) having an opening at a position corresponding to the top surface of the circuit chip, and a shield on the surface facing the top surface of the circuit chip. And a second printed wiring board (printed wiring board 11) laminated on the first printed wiring board. Therefore, even when a plurality of printed wiring boards (printed wiring boards 11 and 12) are stacked and used in the housing, the circuit chip can be sufficiently shielded and the overall thickness of the shield structure can be reduced. .

[0027] In addition, the shield structure according to the first embodiment has a switch element (key switch) that is switched on and off by pressing on the back surface of the surface on which the second printed wiring board force shielding pattern is formed. A pad 42) is provided. Note that when a switch element that can be switched on and off by pressing is provided, a stress is repeatedly applied to the board, and thus a printed wiring board on which such a switch element is generally attached. It is difficult to arrange surface mount components on (printed wiring board 11). The shield pattern according to the first embodiment makes effective use of such a difficult place as a place where the shield pattern is provided, and eliminates the need to take various measures to attach the surface mount component. .

[0028] The shield structure according to the first embodiment is supported by the second printed wiring board force shield frame. Therefore, when the switch element is pressed, the stress applied to the second printed wiring board by the shield frame can be reduced.

[0029] Further, in the shield structure according to the first embodiment, the wall surface of the shield frame body is arranged at a position corresponding to the shield frame body force switch element. Therefore, the stress applied to the second printed wiring board can be further effectively reduced.

[0030] Further, in the shield structure according to the first embodiment, the shield frame provided on the first printed wiring board is in contact with the shield pattern provided on the second printed wiring board. A pattern wiring provided on the first printed wiring board and a pattern wiring provided on the second printed wiring board via a shielding pattern and the shield frame. Conducted.

On the other hand, when conducting the first printed wiring board and the second printed wiring board, for example, it is considered that the first printed wiring board and the second printed wiring board are conducted only by the connector. It is done.

In this case, the GND part where the connector force of the first printed wiring board is also away from the GND part where the connector force of the second printed wiring board is also away is the opposite position. Even so, the potential between the parts may differ to the extent that the electrical performance is affected.

In contrast, in the shield structure according to the first embodiment, the shield frame provided on the first printed wiring board and the pattern wiring board provided on the second printed wiring board are electrically connected. Therefore, the electrical characteristics can be effectively improved because there is little difference in GND potential between the first printed wiring board and the second printed wiring board.

In the shield structure according to the first embodiment, the first printed wiring board has the first connector, the second printed wiring board has the second connector, and the second printed wiring board has the second connector. This is a shield structure in which the connector and the first connector fit together.

On the other hand, when determining the relative positional relationship between the first printed wiring board and the second printed wiring board, attach the first printed wiring board to the frame and attach the second printed wiring board to the frame. It is also possible.

In this case, the positioning accuracy required between the second printed wiring board and the frame is added to the positioning accuracy required between the first printed wiring board and the frame. Therefore, the positioning system between the first printed wiring board and the second printed wiring board is not sufficient. As a result, the contact between the shield frame provided on the first printed wiring board and the shield pattern provided on the second printed wiring board is not sufficient, and the electrical performance is sufficiently improved. It is thought that it is not done.

In contrast, in the shield structure according to the first embodiment, the connector provided on the first printed wiring board and the connector provided on the second printed wiring board are fitted to each other, and the relative positional relationship is established. Therefore, the first printed wiring board and the second printed wiring board can be positioned with high accuracy. As a result, the electrical performance is good with high accuracy. [0032] In the shield structure according to the first embodiment, the circuit chip is a CPU chip or a memory chip.

On the other hand, the part to be shielded may be a high-frequency part used for transmission and reception. Even in this case, the shield frame provided on the first printed wiring board and the shield pattern provided on the second printed wiring board can be sufficiently shielded. Is possible.

However, when laminating the second printed wiring board on the first printed wiring board, the shield frame provided on the first printed wiring board and the shield pattern provided on the second printed wiring board When joining, the joining work becomes complicated.

On the other hand, the shield structure according to the first embodiment is a relatively low-frequency chip in which the components to be shielded are a memory chip and a CPU chip! /.

Therefore, it is not necessary to join the shield frame and the shield pattern, and the assembly work is not complicated.

In addition, a circuit chip that shields even if there is a stagnation of the second printed wiring board provided with the shield pattern or a gap due to unevenness of the shield frame provided on the first printed wiring board of 100 m or more. However, if it is a memory chip or a CPU chip, it has a relatively low frequency, so that it can function sufficiently.

[0033] In addition, in the shield structure according to the first embodiment, since the circuit chip is a BGA type, the effect of reducing the thickness of the entire shield structure is particularly remarkable.

The reason will be specifically described below.

Consider the case where a second printed wiring board is stacked on a first printed wiring board equipped with a shield case. In this case, the thickness from the first printed wiring board to the second printed wiring board is the sum of the following four, which raises the problem that the overall thickness of the shield structure increases.

(1) Bottom force of the first printed wiring board Height to the top of the circuit chip mounted on the top surface of the first printed wiring board

(3) Shield case top plate thickness (4) Shield case top plate upper surface force Clearance to the bottom surface of the second printed wiring board

[0034] The above (2) “gap from the top of the circuit chip to the bottom surface of the shield case top” is the circuit chip force ¾GA chip, the height of the BGA chip part vertex after soldering the part melts the solder ball. Since it is crushed and lowered by about 40 to 50 μm, it is necessary to set the limit value after soldering to about 40 to 50 m larger than the limit value of the minimum interval (2) before soldering.

Therefore, when the circuit chip strength is ¾GA type and the shield frame with the top surface of the circuit chip exposed is used, the top surface of the circuit chip is covered with the shield case when the circuit chip is BGA type. The effect of reducing the overall thickness of the shield structure is significant compared to the previous configuration.

[0035] In addition, the shield structure according to the first embodiment is biased toward the shield pattern provided on the second printed wiring board because of the top plate force of the shield frame. And the shield pattern of the second printed wiring board do not come into contact with or separate from each other. Therefore, the thickness of the entire shield structure can be reduced as compared with a case where the shield frame and the second printed wiring board are sufficiently separated so as not to contact each other.

When the first printed wiring board and the second printed wiring board are fitted by a connector, the second printed wiring board swings relative to the first printed wiring board due to the restoring force of the connector. It becomes easy to do. In such a case, if the shield frame provided on the first printed wiring board and the second printed wiring board are not brought into contact with or separated from each other, the thickness of the shield structure is further increased.

Therefore, when the first printed wiring board and the second printed wiring board are fixed by the fitting of the connector! /, The shield frame and the shield pattern of the second printed wiring board are sufficient. According to the configuration of the present application to be contacted, the effect of reducing the thickness of the shield structure becomes remarkable.

[0036] In the shield structure according to the first embodiment, the opening of the shield frame has a shape in which the solder attaching the circuit chip to the first printed wiring board is exposed.

Therefore, after the circuit chip and the shield frame are automatically mounted on the first printed wiring board and the reflow soldering is performed collectively, the inside of the shield case can be confirmed. Specifically, this shield structure does not have a shield cover top plate after batch reflow. Therefore, the following becomes possible.

(1) In the 4th step, an automatic solder wetness inspection machine can be used to confirm solder bridges and solder non-wetting by comparing images with good products from above the board.

(2) In the sixth step, the test point 7 can be automatically contacted by the robot tester to perform electrical inspection.

(3) In the seventh step, good products that pass all tests can be reinforced by underfilling the lower part of parts that are vulnerable to dropping / shocking such as BGA.

[0037] The shield structure according to the first embodiment is held by a shield frame that covers the back surface of the surface on which the first printed wiring board force circuit chip is mounted.

Therefore, since the frame that holds the first printed wiring board has both the function of holding the first printed wiring board and the function of shielding the bottom side of the first printed wiring board, the shield structure Can be reduced. In addition, since the shield frame and the first printed wiring board are directly connected via the shield cushion, there is a difference in the GND potential between the shield frame and the first printed wiring board. The electrical characteristics can be improved.

[0038] Embodiment 2.

The second embodiment of the present invention will be described below. FIG. 6 is a perspective view showing the internal structure of a mobile phone to which the shield structure of the electronic device according to Embodiment 2 of the present invention is applied. FIG. 7 is a cross-sectional view taken along line 11a-lib in FIG. 6 and 7 have substantially the same configuration as the internal configuration of the mobile phone shown in FIG. 4, and the embodiment in which the circuit chip 24 is interfered with the printed circuit board 11 where the component height is higher than the printed wiring board 11 is shown. This is an example of applying 2.

FIG. 7 (a) shows the assembled method after the printed wiring boards 11 and 12 are assembled, and FIG. 7 (b) shows the assembled method.

In FIG. 7 (b), the circuit chip 24 on at least one side of the printed wiring board 12 (first printed wiring board) contacts or overlaps the shielding copper foil pattern 33 of the printed wiring board 11 in FIG. If this happens, ensure space between the printed circuit board 12 and the circuit chip 24. In order to achieve this, an opening is provided in the printed wiring board 11 (second printed wiring board), and a shield case 32 having a convex recess upward is attached. At that time, a copper foil pattern 111 for shielding is formed on the back surface (circuit chip 24 side) of the printed wiring board 12 so as to surround the opening, and the end portion of the shielding case 32 is brought into contact therewith.

Next, assembly of the printed wiring boards 11 and 12 will be described. The printed wiring board 11 is assembled to the printed wiring board 12 in the direction of the arrow in FIG. Then, as shown in FIG. 7 (a), the connectors 61 and 62 are fitted, the shield frame 31 is pressed against the copper foil pattern for shielding, and the shield case 32 closes the circuit chip 24. Become.

[0041] The shield structure in FIG. 7 includes a shield copper foil pattern 121, a cream solder coating pattern 8, a shield frame 31 (above, printed wiring board 11), a shield copper foil pattern 111, a shield case 32 ( As described above, the printed wiring board 12) is formed by contacting each. Note that the printed wiring boards 11 and 12 are separately assembled in a batch reflow as in the first embodiment, and then the cellular phone It is assembled as described above at the assembly stage.

[0042] As described above, the shield structure according to Embodiment 2 includes the first printed wiring board, the circuit chip having the bottom surface attached to the first printed wiring board, and the circuit chip. A first connector (connector 62) mounted on the same plane as the surface of the first printed wiring board mounted, and attached to the first printed wiring board, covering the side surface of the circuit chip. A shield frame that surrounds the circuit chip and has an opening at a position corresponding to the top surface of the circuit chip, and an opening that is stacked on the first printed wiring board and accommodates the circuit chip. A second printed wiring board having a shield pattern portion (shield copper foil pattern 111) provided in the periphery of the first connector and a second connector (connector 61) that fits the first connector, and the shield putter Attached to the portion, and a shield member (shield cover 32) for covering the circuit switch-up.

Therefore, in addition to the effects of the first embodiment, the height force of the circuit chip mounted on the first printed wiring board is not less than the height between the first printed wiring board and the second printed wiring board. However, a shield structure having a sufficient shielding effect can be applied. [0043] Embodiment 3.

The third embodiment of the present invention will be described below. FIG. 8 is a side view showing the internal configuration of the mobile phone to which the shield structure of the electronic device according to Embodiment 3 of the present invention is applied. FIG. 8A shows an example in which the printed wiring boards 102, 112, 122, and 132 (first to fourth printed wiring boards) are stacked in order of four. Fig. 8 (b) shows the assembly method (arrow direction) of Fig. 8 (a).

In FIG. 8, shield frames 311 and 312 have a structure without the top plate portion of shield frame 32 of FIG. Instead, the printed wiring board 122 (shielding copper foil pattern 83) and 132 (shielding copper foil pattern 344) serve as a shield case top plate.

If the circuit chip 26 has a further height, a printed wiring board having a sufficiently high shield case such as the printed wiring board 11 in FIG. 7 is used instead of the printed wiring board 122. Also good.

Further, when the circuit chip 26 does not exist, the printed wiring board 122 can be omitted and a stacked structure of up to three stages can be adopted.

[0045] The shield structure in FIG. 8 includes a shield copper foil pattern 341, a cream solder coating pattern 8, a shield frame 31 (above, printed wiring board 102), a shield copper foil pattern 81, and a shield frame 311. (Printed wiring board 112), shielded copper foil pattern 82, shield frame (printed wiring board 122), shielded copper foil pattern 344 (printed wiring board 13 2). Is done.

[0046] Further, since the heights of the circuit chip 25 and the circuit chip 26 are different, the printed frame from the printed wiring board 102 to the shield frame 311 of the printed wiring board 112, the shield frame 312 of the printed wiring board 122, and the printed circuit board serving as the shield case top plate. Up to the wiring board 132 has a reverse staircase shape (Fig. 8 (a)).

[0047] Furthermore, by alternately combining the shield frame and the shielding copper foil pattern, it is possible to stack any number of printed wiring boards. In addition, the four printed wiring boards are independent of each other and can be easily disassembled.

Other configurations are substantially the same as those in the first and second embodiments.

[0048] As described above, the shield structure according to Embodiment 3 includes the first printed wiring board (printed wiring board 102) and the first printed wiring board having the bottom surface attached to the first printed wiring board. Circuit (Circuit chip 25) and the first printed circuit board to which the first circuit chip is attached. Second high-speed circuit chip (circuit chip 26) and the first and second circuit chips are attached to the first printed wiring board and cover the side surfaces of the first and second circuit chips. A shield frame (shield frame 311) having an opening at a position corresponding to the top surface of the circuit chip, and laminated on the first printed wiring board. A first shield pattern portion (shield copper foil pattern 82) formed on the surface facing the top surface, an opening for accommodating the second circuit chip, and a second shield provided around the opening Second pattern part (shield copper foil pattern 82) Comprising printed wiring boards (the printed wiring board 122), attached to said second shielding pattern portion, and a shield member covering the second circuit chip (shielding copper foil pattern 344). Therefore, the distance between the first printed wiring board and the second printed wiring board can be adjusted to the height of the short circuit chip.

In the shield structure according to the third embodiment, the shield member covers the side surface of the second circuit chip and surrounds the second circuit chip, and the top of the second circuit chip. A shielding pattern is formed on a surface opposite to the surface, and a third printed wiring board is stacked on the first printed wiring board. Therefore, a circuit chip having an arbitrary height can be used within the total thickness range of the printed wiring boards.

In addition, as shown in Fig. 8 (a), the height of each printed wiring board is such that the printed wiring board on which the circuit chip to be shielded is mounted to the printed wiring board that is the shield case top plate has a reverse staircase shape. By selecting the size, circuit chips etc. can be mounted on each layer pattern other than one side of the printed wiring board used for the shield case top board, or on the printed wiring board not used for the shield case top board. Can be used effectively.

In addition, the same effect as in Embodiment 1 can be obtained except for the effect of reducing fatigue of each part due to key pressing.

In FIGS. 1 to 8, for convenience, the description has been made using expressions such as up, down, left, and right. However, actual electronic devices have various installation directions or directions in use, and are limited to the directions used in the above description. It ’s not something that ’s done. Industrial applicability

As described above, by applying the shield structure according to the present invention and stacking the printed wiring boards in the housing, the thickness of the electronic device, particularly the entire portable device can be reduced.

Claims

The scope of the claims

[1] a first printed wiring board;

A circuit chip having a bottom surface attached to the first printed wiring board;

A shield frame that is attached to the first printed wiring board, covers a side surface of the circuit chip, surrounds the circuit chip, and has an opening at a position corresponding to the top surface of the circuit chip;

A shield structure, comprising: a second printed wiring board having a shielding pattern formed on a surface facing the top surface of the circuit chip and laminated on the first printed wiring board.

[2] The second printed wiring board is

2. The shield structure according to claim 1, wherein a switch element that is switched on and off by pressing is disposed on the back surface of the surface on which the shield pattern is formed.

[3] The second printed wiring board is

3. The shield structure according to claim 2, wherein the shield structure is supported by a shield frame.

[4] The shield frame is

4. The shield structure according to claim 3, wherein a wall surface of the shield frame is disposed at a position corresponding to the switch element.

[5] The shield frame provided on the first printed wiring board is

Abuts the shielding pattern provided on the second printed wiring board,

The pattern wiring provided on the first printed wiring board and the pattern wiring provided on the second printed wiring board are electrically connected via the shield pattern and the shield frame. The shield structure according to claim 1.

[6] The first printed wiring board has the first connector,

The second printed wiring board has a second connector,

6. The shield structure according to claim 5, wherein the second connector and the first connector are fitted to each other.

[7] The circuit chip is

2. The shield structure according to claim 1, wherein the shield structure is a CPU chip or a memory chip.

[8] The opening of the shield frame is

2. The shield structure according to claim 1, wherein the solder that attaches the circuit chip to the first printed wiring board is exposed.

[9] The shield structure according to claim 1, wherein the first printed wiring board is held by a shield frame that covers the back surface of the surface on which the circuit chip is mounted.

[10] a first printed wiring board;

A first connector mounted on the same surface as the surface of the first printed wiring board to which the circuit chip is mounted;

An opening for receiving the circuit chip; a second shield pattern portion provided around the opening; and a second connector that fits the first connector. A second printed wiring board;

A shield structure, comprising: a shield member attached to the shield pattern portion and covering the circuit chip.

[11] a first printed wiring board;

A first circuit chip having a bottom surface attached to the first printed wiring board, and a bottom surface mounted on the same surface as the surface of the first printed wiring board to which the first circuit chip is attached. A second circuit chip that is taller than the first circuit chip; and the first and second circuit chips that are attached to the first printed wiring board and cover side surfaces of the first and second circuit chips. A shielding frame having an opening at a position corresponding to the top surface of the circuit chip,

A surface laminated on the first printed wiring board and facing the top surface of the first circuit chip A second printed wiring board having a first shielding pattern portion formed on the first opening, an opening for accommodating the second circuit chip, and a second shielding pattern portion provided around the opening;

A shield structure comprising: a shield member attached to the second shield pattern portion and covering the second circuit chip.

The shield member

A shielding frame that covers a side surface of the second circuit chip, surrounds the second circuit chip, and has an opening provided at a position corresponding to the top surface of the second circuit chip;

And a third printed wiring board laminated on the first printed wiring board, wherein a shielding pattern is formed on a surface facing the top surface of the second circuit chip. The shield structure described in Item 11.