JP2005093924A - Electronic component mounted module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component mounted module in which electronic component mounting regions and patterned wiring regions are increased and which has a structure that can easily evaluate the mounted components. <P>SOLUTION: The electronic component mounted module 10 comprises an LSI 11, a printed board 12 for mounting the LSI 11, and a case 20 for housing the printed board 12. An electrically conductive contact film 14 for electrically conducting the LSI 11 to the printed board 12 is inserted between the LSI 11 and the printed board 12, and a pushing member 13 for pushing the LSI 11 is fastened to the printed board to mount the LSI 11 on the printed board. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic component mounting module on which an electronic component such as an LSI is mounted.

  In recent years, as optical transceivers perform high-speed transmission of 2.5 Gbit / s, 10 Gbit / s, and 40 Gbit / s, the power consumption of LSI (Larage-Scale Integration) that performs signal processing increases, and very expensive elements It has become. In particular, signal processing LSIs (signal multiplexing LSIs and signal separation LSIs) that perform high-speed signal processing of 40 Gbit / s consume a large amount of power and are very expensive. Further, signal processing LSIs are mainly in the form of BGA (Ball Grid Array) packages in which solder balls as connection terminals are arranged in a grid on the bottom of the LSI due to the increase in the number of pins.

  FIG. 6 is a cross-sectional view of an electronic component mounting module 50 in which a conventional BGA package LSI (hereinafter referred to as LSI) 51 is mounted on a printed circuit board 52.

  Solder balls 54 provided on the lower surface of the LSI 51 are directly bonded to the pads 53 formed on the printed circuit board 52 with the solder 55, and the LSI 51 is mounted on the printed circuit board 52. A heat dissipation sheet 56 is provided on the upper surface of the LSI 51, and wiring patterns are formed or other electronic components 57 are mounted on the upper surface and lower surface of the printed circuit board 52 where the LSI 51 is not mounted. The printed circuit board 52 is accommodated in the case 58 and is in electrical contact with the outside via an electrical connector 59 provided in the case 58.

  As described above, as a method of mounting the LSI 51 on the printed board, the conventional technique is to solder the LSI 51 to the printed board 52 for mounting.

  Patent Document 1 describes a conductive contact film used for a BGA package LSI.

  FIG. 7 is a cross-sectional view of a conventional electronic component mounting module 60 in which an LSI 51 is mounted on a printed circuit board 52 using a conductive contact film 61 without directly soldering a solder ball as shown in FIG.

  FIG. 7A shows a cross-sectional view before the LSI 51 is mounted, and FIG. 7B shows a cross-sectional view after the LSI 51 is mounted. A conductive contact film 61 is sandwiched between the LSI 51 and the printed circuit board 52. The conductive contact film 61 is an elastic film made of an insulating material. The lower case 64 has a convex portion 64a for supporting the printed circuit board, the upper case 63 has an LSI pressing portion 63a, and the convex portion 64a and the LSI. The LSI 51, the conductive contact film 61, and the heat dissipation sheet 56 are pressed and fixed onto the printed circuit board 52 by applying a sufficiently large pressure from above and below by the pressing portion 63 a. The conductive ball 62 and the pad 53 are brought into electrical contact with each other by a conductive pin 62 provided on the conductive contact film 61. The upper case 63 and the lower case 64 are fastened with screws 65, and the printed circuit board 52 is accommodated in the case 58.

JP 2001-141780 A

  As shown in FIG. 6, in the mounting technique in which the LSI 51 is soldered to the printed circuit board 52, the LSI 51 cannot be mounted again if it is removed after being mounted once. This is a problem in terms of cost in this mounting technique when evaluating an expensive LSI.

  Further, as shown in FIG. 7, in the mounting technique using the conductive contact film 61, the solder balls 54 of the LSI 51 and the pads of the printed circuit board 52 are covered with the conductive contact film 61 by the pressure sandwiched between the upper and lower cases. 53 was conducted. However, with this mounting method, it becomes impossible to mount a component on the back surface of the LSI 51 mounting surface of the printed circuit board 52 or to wire a pattern, and the electronic component mounting area and the pattern wiring area are reduced. There is a problem.

  Further, since the printed circuit board 52 on which the LSI 51 is mounted is accommodated in the case 58 and the LSI 51 is pressed by the upper case 63 and the lower case 64, the signal of each pin of the component cannot be monitored by a probe or the like. There is also a point.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electronic component mounting module having a structure that can solve the above-described problems, increase an electronic component mounting area and a pattern wiring area, and can easily evaluate a mounted component.

  In order to achieve the above object, an invention according to claim 1 is an electronic component mounting module comprising an LSI, a printed board on which the LSI is mounted, and a case for housing the printed board. In this electronic component mounting module, a conductive contact film to be conducted is inserted between an LSI and a printed board, and a pressing member for pressing the LSI is fixed to the printed board and the LSI is mounted on the printed board.

  In the invention of claim 2, the pressing member is formed in a box shape in which a recess for accommodating an LSI is formed, and has a plurality of protrusions for engaging the board with the box body. The electronic component mounting module according to claim 1, wherein an engagement hole that engages with the protrusion is formed.

  According to a third aspect of the present invention, the pressing member is formed in a box shape having a recess for accommodating the LSI, and the box-shaped pressing member is fixed to the printed circuit board by fastening means to press the LSI against the printed circuit board. The electronic component mounting module according to claim 1 or 2 as described above.

  According to a fourth aspect of the present invention, in the electronic component mounting module according to the third aspect, the tightening means includes a nut formed on the pressing member or the substrate, and a screw inserted into the substrate or the pressing member and screwed into the nut. is there.

  According to a fifth aspect of the present invention, in the electronic component according to any one of the first to third aspects, the printed circuit board is supported on the bottom surface of the case facing the back side of the LSI mounting surface of the printed circuit board, and a convex portion smaller than the LSI mounting area is formed. It is a mounting module.

  The invention according to claim 6 is the electronic component mounting module according to claim 5, wherein a heat dissipation sheet is inserted between the convex portion of the case and the printed board.

  According to the present invention, it is possible to exhibit an excellent effect that a component mounting area and a pattern wiring area of a printed circuit board can be secured widely.

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

(Embodiment 1)
FIG. 1 shows a cross-sectional view of an electronic component mounting module 10 according to the present embodiment. 1A is a cross-sectional view of the LSI 11 before mounting, and FIG. 1B is a cross-sectional view of the LSI 11 mounted. FIG. 2 is a view taken along the line A in FIG.

  As shown in FIG. 1, the electronic component mounting module 10 is provided with a conductive contact film 14 on the upper surface of a printed circuit board 12, an LSI 11 as an upper layer, and a pressing member 13 of the LSI 11 as an upper layer.

  As shown in FIG. 3, the pressing member 13 is formed in a box shape in which a recess 13 b for accommodating the LSI 11 is formed, and is formed of a metal material. At the four corners of the wall forming the recess 13b of the pressing member 13, protrusions 13a for engaging with the printed circuit board 12 are formed so as to protrude downward. Since the pressing member 13 is formed of a metal material, noise emission from the LSI 11 and noise intrusion into the LSI 11 can be prevented.

  Since the printed circuit board 12 can withstand the pressure applied by the pressing member 13, the thickness thereof is as thick as 2 mm. Engagement holes 12a are formed at four positions of the engagement positions. The engagement hole 12a is formed by countersinking the printed circuit board 12, and does not penetrate to the back surface (lower side in the figure). By not using the engagement hole 12a as a through hole, the mounting area of the other electronic component 19 can be increased on the back surface of the printed circuit board 12.

  The LSI 11 includes a plurality of solder balls 15 as connection terminals on the lower surface thereof, and a heat dissipation sheet 17 is provided on the upper layer of the LSI 11 and the upper layer of the pressing member 13 in order to suppress thermal runaway due to heat generated by the LSI 11. Instead of the heat dissipating sheet 17, heat dissipating grease may be applied.

  The conductive contact film 14 includes pins 14a. The conductive contact film 14 is an elastic film formed of an insulator, and the pins 14 a conduct the conductor pressed on both the front and back surfaces of the conductive contact film 14. When the LSI 11 and the conductive contact film 14 are mounted on the printed circuit board 12, the solder balls 15 of the LSI 11 and the pads 16 of the printed circuit board 12 are in electrical contact via pins 14a.

  As shown in FIG. 1B, the conductive contact film 14 is laminated on the pad 16 of the printed circuit board 12, the LSI 11 is laminated on the upper layer so that the solder balls 15 are engaged, and the heat radiation sheet 17 is laminated on the upper layer. The pressing member 13 is fixed to the printed circuit board 12 so that the four protrusions 13 a from the upper layer are fitted into the engagement holes 12 a on the printed circuit board 12.

  A case 20 that accommodates the printed circuit board 12 includes an upper case 18 and a lower case 21. A large number of protrusions 18a are formed on the outer side of the upper case 18 so that heat can be easily radiated, and a convex portion 21a for supporting the printed circuit board 12 is formed on the bottom surface of the lower case 21, thereby electrically connecting the external power source and the printed circuit board 12 An electrical connector 22 to be connected is provided. The convex portion 21a is formed at a position facing the back side of the LSI 11 mounting surface of the printed circuit board 12, and the size thereof is smaller than the LSI mounting area. The printed circuit board 12 is mounted so as to be supported by the convex portion 21 a and the electrical connector 22, the upper case 18 and the lower case 21 are coupled by the case fastening screw 23, and the printed circuit board 12 is accommodated in the case 20.

  Here, it is easy to position the solder ball 15 and the pad 16 by calculating in advance the area of the recess 13b of the pressing member 13, the area of the conductive contact film 14, and the position of the protrusion 13a of the pressing member 13. become.

  Further, the heat radiating sheet 17 is inserted between the pressing member 13 and the LSI 11 and between the upper case 18 and the pressing member 13. Further, the heat radiating sheet 17 is interposed between the case convex portion 21 a and the printed circuit board 12. Has been inserted. By inserting the heat radiation sheet 17 between the convex portion 21a and the printed board 12, the heat radiation effect is enhanced. Moreover, you may apply | coat the grease for thermal radiation instead of the sheet | seat 17 for thermal radiation.

  The operation and effect of the present embodiment will be described.

  In the electronic component mounting module 10 of the present embodiment, the LSI 11 is mounted on the printed circuit board 12, the solder balls 15 and the pads 16 are electrically connected by the conductive contact film 14, and the LSI 11 is pressed and mounted using the pressing member 13. Is.

  The upper case 18 and the lower case 21 are fastened with a case fastening screw 23, and the conductive contact film 14 is pressed using a pressure that sandwiches the printed circuit board 12 or the like, so that the solder ball 15 and the pad 16 on the printed circuit board 21 are pressed. Becomes conductive, and signal transmission becomes possible. At this time, by forming the convex portion 21a supporting the printed circuit board 12 as small as possible in the lower case 21, it is possible to secure a wider electronic component mounting area and pattern wiring area on the back surface of the printed circuit board 12.

  When evaluating the electronic component mounting module 10, the pressing member 13 and the printed circuit board 12 are pressed up and down against an evaluation jig that does not cover the entire printed circuit board 12 without using the case 20, and the conductive contact film. Apply pressure to 14.

  In the conventional electronic component package, since the pressing means for mounting the LSI 11 is integrated with the case, it is difficult to evaluate each electronic component by contacting a probe when evaluating the electronic component mounting module. It was. If the printed circuit board 12 on which the LSI 11 is mounted is removed from the case, the pressing means of the LSI 11 is lost, and the electrical contact between the LSI and the printed circuit board 12 is weakened.

  However, according to the above configuration, since the LSI is pressed by the pressing member, it is easy to attach and detach the printed circuit board 12 on which the LSI 11 is mounted and to the evaluation jig. Thereby, evaluation of the electronic component mounting module 10 which monitors each pin of other mounting components 19 with a probe etc. can be performed simply.

(Embodiment 2)
FIG. 4 shows a cross-sectional view of an electronic component mounting module 30 according to another embodiment of the present invention. 4A shows a cross-sectional view of the state before the LSI 11 is mounted, and FIG. 4B shows a cross-sectional view of the state after the LSI 11 is mounted. Details of the previously described codes are omitted.

  In the first embodiment, the protruding portion 13a of the pressing member 13 is fitted into the engagement hole 12a of the printed circuit board, and the LSI 11 is pressed by the pressure sandwiched by the case 20, but the second embodiment uses a tightening means. The pressing member 32 is fixed to the printed circuit board 31.

  As shown in FIG. 4A, as in the first embodiment, the heat-dissipating sheet 17, the LSI 11, and the conductive contact film 14 are stacked from the upper layer and fixed with the pressing member 32. The pressing member 32 is fixed to the printed circuit board 31 by fastening means.

  The tightening means includes a nut 34 formed on the printed circuit board 31 and a screw 33 inserted through the pressing member 13 and screwed into the nut. Screw holes 32a through which the screws 33 are inserted are formed at the four corners of the wall forming the recess 32b of the pressing member 32, respectively. On the printed circuit board 31, nuts 34 having a diameter of 1 mm are formed at four positions where screws 33 inserted through the pressing member 32 are screwed.

  Since the electronic component mounting module 30 fixes the pressing member 32 only by tightening means, the convex portion 21a for supporting the printed circuit board 12 formed in the lower case 21 as shown in FIG. 1 is not necessary. Therefore, almost all areas on the back side of the printed circuit board 31 can be used for mounting the electronic component 19 and pattern wiring.

  Since the pressing member 32 is fixed to the printed circuit board 31 by the fastening means and presses the LSI 11 and the like, the LSI 11 and the like are pressed even without the upper case 18. Therefore, when evaluating the electronic component mounting module 30, it is not necessary to use a separate jig, and the mounted other electronic component 19 can be exposed while the LSI 11 is pressed only by removing the upper case 18. Thereby, a probe can be made to contact the other electronic component 19 on the printed circuit board 31, and it can evaluate more simply.

(Embodiment 3)
FIG. 5 shows a cross-sectional view of the electronic component mounting module 40 of the third embodiment. FIG. 5A shows a cross-sectional view of the state before the LSI 11 is mounted, and FIG. 5B shows a cross-sectional view after the LSI 11 is mounted.

  As shown in FIG. 5A, the fastening means of the pressing member 42 that presses the LSI 11 or the like against the printed board 41 is inserted into the printed board 41 and the nut 44 formed on the pressing member 42, and the nut 44 is screwed. And a screw 43 to be joined.

Furthermore, in the second embodiment, the screw holes 32a of the pressing member 32 and the nuts 34 on the printed circuit board 31 formed so as to be screwed to the screw holes 32a are formed at four locations, respectively. Two nuts 44 and screw holes 41a through which the screws 43 are inserted are formed at two positions on the printed circuit board formed at positions where they are screwed together.
The conductive contact film 14, the LSI 11, and the heat dissipation sheet 17 on the printed circuit board 41 are fixed by the pressing member 42, and the screw 43 is inserted into the screw hole 41a from the back surface of the printed circuit board 41. The screw 43 and the nut 44 of the pressing member 42 are inserted. And press to tighten.

  According to the above configuration, as in the second embodiment, sufficient pressure can be obtained without providing the convex portion 21a for supporting the printed circuit board, so that the electronic component mounting area on the back surface of the printed circuit board 41 can be increased. Become.

  Further, when evaluating the electronic component mounting module 40, the probe can be brought into contact with each electronic component 19 on the printed circuit board 41 simply by removing the upper case 18, and the evaluation can be performed more easily.

  From the above, in the electronic component mounting modules 10, 30, 40 for mounting the LSI 11 on the printed circuit boards 12, 31, 41 using the conductive contact film 14, pressure is applied to the conductive contact film 14 using the pressing member 13, By mounting the LSI 11 or the like, it is possible to secure a wide electronic component mounting area and pattern wiring area on the back surface of the printed circuit board opposite to the LSI 11.

  Further, by adopting a structure in which pressure is applied to the conductive contact film 14 by using a pressing member instead of pressing by tightening the case, the upper case 18 can be removed while the LSI 11 is pressed during the evaluation. can do.

  In the second embodiment, the pressing member 32 may be fixed at only two locations on the diagonal line of the pressing member 32 instead of the four screws 33 and nuts 34 that are tightening means.

  In the third embodiment, the screws and nuts, which are tightening means, are formed not only at two locations on the diagonal line, but also at all four corners of the wall forming the concave portion of the pressing member 42, and the pressing member 42 is fixed. May be.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows Embodiment 1 of the electronic component mounting module which concerns on this invention, (a) shows the state before LSI mounting, (b) shows the state after LSI mounting. It is an A line arrow directional view of Drawing 1 (b). It is a perspective view of a pressing member. It is sectional drawing which shows Embodiment 2 of this invention, (a) shows the state before LSI mounting, (b) shows the state after LSI mounting. It is sectional drawing which shows Embodiment 3 of this invention, (a) shows the state before LSI mounting, (b) shows the state after LSI mounting. It is sectional drawing of the electronic component mounting module which mounted LSI by the conventional soldering. It is sectional drawing of the electronic component mounting module using the conventional conductive contact film, (a) shows the state before LSI mounting, (b) shows the state after LSI mounting.

Explanation of symbols

10 Electronic Component Mounting Module 11 LSI
12 Printed circuit board 12a Engagement hole 13 Press member 13a Protrusion 13b Recess 14 Conductive contact film 17 Heat dissipation sheet 20 Case 33, 43 Screw 34, 44 Nut

Claims (6)

  In an electronic component mounting module including an LSI, a printed circuit board on which the LSI is mounted, and a case for housing the printed circuit board, a conductive contact film for electrically connecting the LSI to the printed circuit board is interposed between the LSI and the printed circuit board. An electronic component mounting module, wherein an electronic component mounting module is characterized in that an LSI is mounted on a printed board by inserting a pressing member that presses the LSI onto the printed board.   The pressing member is formed in a box shape having a recess for accommodating an LSI, and has a plurality of protrusions for engaging the board with the box, and the printed board is engaged with the protrusions. The electronic component mounting module according to claim 1, wherein an engaging hole is formed.   2. The pressing member is formed in a box shape having a concave portion for accommodating an LSI, and the box-shaped pressing member is fixed to a printed circuit board by fastening means to press the LSI against the printed circuit board. Or the electronic component mounting module of 2.   4. The electronic component mounting module according to claim 3, wherein the tightening means includes a nut formed on the pressing member or the substrate, and a screw inserted through the substrate or the pressing member and screwed into the nut.   The electronic component mounting module according to any one of claims 1 to 3, wherein a convex portion smaller than an LSI mounting area is formed on the bottom surface of the case facing the back side of the LSI mounting surface of the printed board. The electronic component mounting module according to claim 5, wherein a heat dissipation sheet is inserted between the convex portion of the case and the printed board.

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