JP2016072325A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device that prevents a package from being warped by heating during soldering and the like, without use of a correction jig and without addition of a new step.SOLUTION: An electronic device includes a rectangular plate-like package 11, and a temperature-sensitive deformation member 13 which is arranged in at least one of four corner areas of the package 11 and which includes a longitudinally-shaped flat part elongated in a principal-plane diagonal direction of the package 11. Both longitudinal ends of the temperature-sensitive deformation member 13 are fixed to the package 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic device.

For example, when an IC chip such as a BGA (Ball Grid Array) is mounted on a package, solder bumps are provided on the BGA case, and after the BGA is disposed on the package, the solder bumps are heated and melted for bonding. Has been done. In addition, as an example in which an attempt to prevent warping of BGA or the like during heating and melting is performed, Patent Document 1 discloses that a warpage of a BGA case generated during soldering is warped on the BGA case. A BGA case warpage correction method that corrects by mounting and reflowing again is disclosed.

  Patent Document 2 discloses a substrate transport carrier provided with tension applying means for pulling the outer peripheral portion of the printed circuit board in the tension applying direction away from the center of the printed circuit board.

  Patent Document 3 discloses a method for manufacturing a package in which a flattening jig is disposed on an upper main surface of a package and heated in this state to melt a solder material.

Japanese Patent Laid-Open No. 11-54908 JP 2007-324473 A JP-A-10-56156

  When the method disclosed in Patent Document 1 is used, a process of reflowing again after soldering the BCA case is necessary, which increases the number of processes. In addition, there is a problem that a part cannot be mounted on a portion where the correction jig contacts.

  Moreover, when using the conveyance carrier currently disclosed by patent document 2, since it was necessary to use a special conveyance carrier and the conveyance carrier itself was formed with a bimetal, there existed a problem that cost was high.

  Further, when the method disclosed in Patent Document 3 is used, there is a problem in that an area where components cannot be mounted is generated directly below and around the regulating member.

  The present invention has been made in view of the above points. For example, it is possible to prevent warping of a package due to heating during soldering without using a correction jig and without adding a new process. It is an object to provide an electronic device.

  The electronic device of the present invention includes a rectangular plate-shaped package and a temperature-sensitive deformation that is disposed in at least one of the four corner regions of the package and has a long flat portion extending in the diagonal direction of the main surface of the package. An electronic device including a member, wherein both end portions in the longitudinal direction of the temperature-sensitive deformation member are fixed to the package.

  In addition, the electronic device of the present invention includes a rectangular plate-shaped package, a temperature-sensitive deformable member that is disposed along each side of the package, and includes a long flat portion extending along each side of the package, The temperature-sensitive deformable member is fixed to the package at both ends in the longitudinal direction.

FIG. 1A is a top view of an electronic device that is Embodiment 1 of the present invention, and FIG. 1B is a cross-sectional view taken along the 1b-1b section of the electronic device of FIG. It is a perspective view of the temperature-sensitive deformation member contained in the electronic device of FIG. It is sectional drawing in the process of mounting an electronic device in a wiring board. 4A is a top view of an electronic device that is Embodiment 2 of the present invention, and FIG. 4B is a cross-sectional view taken along a 4b-4b cross section of the electronic device of FIG. 4A. It is a perspective view of the temperature-sensitive deformation member contained in the electronic device of FIG. It is sectional drawing in the process of mounting an electronic device in a wiring board. FIG. 7A is a top view of an electronic device that is Embodiment 3 of the present invention, and FIG. 7B is a cross-sectional view of the electronic device taken along section 7b-7b of FIG. 4A. It is a perspective view of the temperature-sensitive deformation member contained in the electronic device of FIG. It is sectional drawing in the process of mounting an electronic device in a wiring board. FIG. 10A and FIG. 10B are cross-sectional views of an electronic device that is a modification of the present invention. It is sectional drawing of the electronic device which is a modification of this invention. 12A is a top view of an electronic device that is a modification of the present invention, and FIG. 12B is a cross-sectional view of the electronic device of FIG. 12A taken along the 12b-12b cross section.

  In the following, referring to FIG. 1 (b) and FIG. 2 which are sectional views taken along line 1b-1b of FIG. 1 (a) and FIG. 1 (a) for the electronic device 10 which is Embodiment 1 of the present invention. I will explain.

  The package 11 is a rectangular plate package formed by resin-sealing an IC or the like (not shown). A plurality of solder bumps 12 for joining the package 11 and the wiring board are formed on the lower surface of the package 11, that is, in the central region of the surface facing the wiring board (not shown) when mounted on the wiring board.

  In the four corner regions on the lower surface of the package 11, temperature-sensitive deformation members 13 are arranged, respectively. The temperature-sensitive deformation member 13 has a flat shape (see FIG. 2) having a substantially C-shaped (U-shaped) cross section that is bent so as to have a concave shape with respect to the package 11.

  As shown in FIGS. 1B and 2, the temperature-sensitive deformable member 13 is in the form of a rectangular flat plate that is in contact with the lower surface of the package 11 and extends along the diagonal line of the main surface of the package 11, that is, a flat plate having a long shape. The base part 13A as a part and the rising parts 13B each having a rectangular shape rising vertically from both ends of the base part 13A. The rising portion 13B is embedded in the package 11 from the lower surface of the package 11, that is, embedded and fixed. That is, the base portion 13A is fixed to the package 11 via the rising portions 13B at both ends thereof.

  The rising portion 13B may be fixed by, for example, integrally molding the package 11 and the temperature-sensitive deformation member 13. Further, for example, a hole having a shape corresponding to the rising portion 13B is formed in the package 11, the rising portion 13B is inserted into the hole, and the rising portion 13B and the hole are fixed with a heat-resistant adhesive. May be.

  FIG. 2 is a perspective view of the temperature-sensitive deformation member 13. As shown in FIG. 2, the temperature-sensitive deformation member 13 is a low-expansion portion 15 made of an invar alloy (Ni—Fe), which is a low-expansion portion, and a surface facing the lower surface of the low-expansion portion 15 package (not shown). It is a bimetal which has the high expansion part 17 which consists of copper which is the high expansion part formed on the top. That is, the base portion 13A of the temperature-sensitive deformation member 13 is deformed so as to be convex with respect to the package 11 when heated in a process such as reflow.

  FIG. 3 shows a 1b-1b cross section of the electronic device 10 when mounted on the wiring board S. In FIG. 3, the deformation force generated in the electronic device 10 when heated is indicated by an arrow. When the electronic device 10 is mounted on the wiring board S, a reflow process that is heated for soldering is performed. At this time, the package 11 of the electronic device 10 warps so as to protrude upward or downward due to heat. In this description, it is assumed that the package 11 is warped and deformed so as to protrude downward when heated.

  When the electronic device 10 is heated in the reflow process, an upward deformation force (shaded arrow in the figure), that is, a deformation force in a direction away from the wiring board S is generated at the corner portion 11C of the package 11. On the other hand, when the temperature-sensitive deformation member 13 is heated as described above, the temperature-sensitive deformation member 13 is deformed to be convex upward, that is, to be convex with respect to the package 11. That is, the temperature-sensitive deformable member 13 has a corner portion of the package 11 at the other end portion, which is an action point portion, with one end portion of the base portion 13A fixed to the package by the rising portion 13B near the center of the package 11 as a fulcrum portion. A force for pulling 11C downward (open arrow in the figure) is generated.

  Therefore, even when the electronic device 10 is exposed to a high temperature, for example, during reflow processing, and a force that warps upward is applied to the corner of the package 11, the temperature-sensitive deformation member 13 faces the corner 11C of the package 11 downward, That is, by pulling toward the wiring board S, it is possible to cancel the upward force and prevent the corner 11C of the electronic device 10 from warping.

  As a result, the solder bumps 12 formed near the end of the electronic device 10 are prevented from separating from the wiring board S due to the warp of the electronic device 10 due to heat, and the wiring between the electronic device 10 and the wiring is prevented. It is possible to prevent the occurrence of bonding failure with the substrate S.

  Note that the temperature-sensitive deformation member 13 may be arranged in another region around the package 11 in addition to the four corner regions or instead of the four corner regions. For example, when arranging along each side of the main surface of the package 11, the base portion 13 </ b> A extends along a direction perpendicular to each side along which the temperature-sensitive deformable member 13 extends, and rises at both ends in the extending direction. It is preferable that the portion 13B is formed.

  4B and 5 which are sectional views taken along line 4b-4b of FIG. 4A and FIG. 4A, with respect to the electronic device 20 which is Embodiment 2 of the present invention. I will explain.

  Similar to the electronic device 10 of the first embodiment, the package 11 is a rectangular plate package formed by resin-sealing an IC or the like (not shown). A plurality of solder bumps 12 for joining the package 11 and the wiring substrate are formed on the lower surface of the package 11, that is, in the central region of the surface facing the wiring substrate when mounted on the wiring substrate.

  Each of the four temperature-sensitive deformation members 23 is disposed along the four sides of the lower surface of the package 11. The temperature-sensitive deformation member 23 has a flat shape (see FIG. 5) having a substantially C-shaped cross section that is bent so as to be concave with respect to the package 11.

  As shown in FIGS. 4B and 5, the temperature-sensitive deformation member 23 is in the form of a rectangular flat plate extending along each side of the lower surface in contact with the lower surface of the package 11, that is, as a long flat portion. The base portion 23A and rectangular rising portions 23B each rising vertically from both end portions in the longitudinal direction of the base portion 23A. The rising portion 23B is embedded in the package 11 from the lower surface of the package 11, that is, buried and fixed. That is, the base portion 23A is fixed to the package 11 via the rising portions 23B at both ends thereof.

  As in the first embodiment, the rising portion 23B may be fixed by, for example, integrally molding the package 11 and the temperature-sensitive deformation member 23. Further, for example, a hole having a shape corresponding to the rising portion 23B is formed in the package 11, the rising portion 23B is inserted into the hole, and the rising portion 23B and the hole are fixed with a heat resistant adhesive. May be.

  As shown in FIG. 5, the temperature-sensitive deformation member 23 is a low-expansion portion 15 made of Invar alloy (Ni—Fe), which is a low-expansion portion, and a surface facing the lower surface of the low-expansion portion 15 package (not shown). It is a bimetal which has the high expansion part 17 which consists of copper which is the high expansion part formed on the top. That is, the base 23A of the temperature-sensitive deformation member 23 is deformed so as to be convex with respect to the package when heated in a process such as reflow.

  FIG. 6 is an enlarged view of the end of the 4b-4b cross section of the electronic device 20 when mounted on the wiring board S. FIG. In FIG. 6, the deformation force generated in the electronic device 20 when heated is indicated by an arrow. When the electronic device 20 is mounted on the wiring board S, a reflow process for heating for soldering is performed. At this time, the package 11 of the electronic device 20 warps so as to protrude upward or downward due to heat. In this description, it is assumed that the package 11 is warped and deformed so as to protrude downward when heated.

  When the electronic device 20 is heated in the reflow process, an upward deformation force (shaded arrow in the figure), that is, a deformation force in a direction away from the wiring board S is generated in the corner portion 11C of the package 11. On the other hand, when the temperature-sensitive deformation member 23 is heated as described above, the temperature-sensitive deformation member 23 is deformed to be convex upward, that is, to be convex with respect to the package 11. That is, the temperature-sensitive deformation member 23 generates a force (a white arrow in the drawing) that pulls the corner 11C of the package 11 downward at both ends of the base 23A fixed to the package 11 by the rising portion 23B.

  Therefore, even when the electronic device 20 is exposed to a high temperature, for example, during reflow processing, and a force that warps upward is applied to the corner 11C of the package 11, the temperature-sensitive deformation member 23 faces the corner 11C of the package 11 downward. In other words, by pulling toward the wiring board S, the upward force can be offset and the warp of the electronic device 20 can be prevented.

  This prevents the solder bump 12 formed near the end of the electronic device 20 from causing a bonding failure due to the electronic device 20 being separated from the wiring substrate S by warping due to heat. Is possible.

  In the following, referring to FIG. 7 (b) and FIG. 8 which are sectional views taken along line 7b-7b of FIG. 7 (a) and FIG. 7 (a) for the electronic device 30 which is Embodiment 3 of the present invention. I will explain.

  Similar to the electronic device 10 of the first embodiment, the package 11 is a rectangular plate package formed by resin-sealing an IC or the like (not shown). A plurality of solder bumps 12 for joining the package 11 and the wiring substrate are formed on the lower surface of the package 11, that is, in the central region of the surface facing the wiring substrate when mounted on the wiring substrate.

  Each of the four temperature-sensitive deformation members 33 is arranged along the four sides of the lower surface of the package 11. The temperature-sensitive deformation member 33 has a longitudinal groove shape (see FIG. 8) having a substantially C-shaped cross section that is bent so as to be concave with respect to the package 11.

  As shown in FIGS. 7B and 8, the temperature-sensitive deformable member 33 is a rectangular flat plate extending along each side of the lower surface in contact with the lower surface of the package 11, that is, as a long flat portion. Base portion 33A, and a rectangular rising portion 33B that vertically rises from both ends in the short direction of the base portion 33A. The rising portion 33B is embedded in the package 11 from the lower surface of the package 11, that is, buried and fixed. That is, the base portion 33A is fixed to the package 11 via the rising portions 33B at both ends thereof.

  The rising portion 33B may be fixed by, for example, integrally molding the package 11 and the temperature-sensitive deformation member 33. Further, for example, a hole having a shape corresponding to the rising portion 33B is formed in the package 11, the rising portion 33B is inserted into the hole, and the rising portion 33B and the hole are fixed with a heat-resistant adhesive. May be.

  As shown in FIG. 8, the temperature-sensitive deformation member 33 is a low-expansion portion 15 and a low-expansion portion 15 made of Invar alloy (Ni—Fe), which are low-expansion portions, as with the temperature-sensitive deformation member 13 of the first embodiment. It is a bimetal which has the high expansion part 17 which consists of copper which is the high expansion part formed on the surface facing the lower surface of the package 11. That is, the base 33A of the temperature-sensitive deformation member 33 is deformed so as to be convex with respect to the package 11 when heated in a process such as reflow.

  FIG. 9 shows an enlarged view of the end of the 7b-7b cross section of the electronic device 30 when mounted on the wiring board S. FIG. In FIG. 9, the deformation force generated in the electronic device 30 when heated is indicated by an arrow. When the electronic device 30 is mounted on the wiring board S, a reflow process that is heated for soldering is performed. At this time, the package 11 of the electronic device 30 warps so as to protrude upward or downward due to heat. In this description, it is assumed that the package 11 is warped and deformed so as to be convex on the lower surface when heated.

  When the electronic device 30 is heated in the reflow process, an upward deformation force (shaded arrow in the figure), that is, a deformation force in a direction away from the wiring board S is generated at the peripheral edge portion 11C of the package 11. In contrast, when the temperature-sensitive deformation member 33 is heated as described above, the temperature-sensitive deformation member 33 is deformed so as to protrude upward, that is, to protrude toward the package 11. That is, the temperature-sensitive deformable member 33 has a corner portion of the package 11 at the other end portion as an action point portion with one end portion of the base portion 33A fixed to the package by the rising portion 33B near the center of the package 11 as a fulcrum portion. A force for pulling 11C downward (open arrow in the figure) is generated.

  Therefore, even when the electronic device 30 is exposed to a high temperature, for example, during reflow processing, and a force that warps upward is applied to the peripheral portion 11C of the package 11, the temperature-sensitive deformation member 23 faces the peripheral portion 11C of the package 11 downward. In other words, by pulling toward the wiring board S, the upward force can be canceled and the warp of the electronic device 30 can be prevented.

  This prevents the solder bump 12 formed near the end of the electronic device 30 from causing a bonding failure due to separation of the electronic device 30 from the wiring board S due to warpage due to heat. Is possible.

  In the above embodiment, the base portions 13A, 23A, 33A of the temperature-sensitive deformation members 13, 23, 33 are in contact with the lower surface of the package 11, but the base portions 13A, 23A, 33A are separated from the lower surface of the package 11. It is good to be.

  Moreover, in the said Example, the temperature sensitive deformation members 13, 23, and 33 have a substantially C-shaped cross section which consists of base part 13A, 23A, 33A and the rising part 13B, 23B, 33B which stood | started up perpendicularly from the both ends. An example was described.

  However, the end portions of the base portions 13A, 23A, 33A are fixed to the package 11 so that the temperature-sensitive deformation members 13, 23, 33 give the package 11 the force generated by the warp of the base portions 13A, 23A, 33A. The cross-sectional shape is not limited to the above-described embodiment.

  For example, even when the rising portions 13B, 23B, and 33B rise from the base portions 13A, 23A, and 33A at an obtuse angle as shown in FIG. 10A, which is a cross-sectional view illustrated as an example corresponding to the first and third embodiments. Alternatively, it may rise at an acute angle as shown in FIG.

  The rising portions 13B, 23B, and 33B may be formed only at one end of the base portions 13A, 23A, and 33A. For example, as shown in FIG. 11 which is a cross-sectional view illustrated as an example corresponding to the first and third embodiments, the temperature-sensitive deformation members 13, 23, 33 rise from the base portions 13A, 23A, 33A and one end thereof at an acute angle. It is good also as having the rising part 13B, 23B, 33B.

  In this case, the corners of the acute angle portions of the temperature-sensitive deformation members 13, 23, 33 protrude from the package 11, and the other ends of the base portions 13A, 23A, 33A and the rising portions 13B, 23B, 33B are packaged. It is good also as the both ends of base part 13A, 23A, 33A being fixed to the package 11 by being embedded in 11, ie, being embedded.

  Moreover, in the said Example, although the example which deform | transforms convexly downward when the package 11 was heated was demonstrated, this invention is applicable also when deform | transforming convexly upward. For example, in this case, the low-expansion part 15 and the high-expansion part 17 of the temperature-sensitive deformation members 13, 23, 33 may be arranged in reverse. That is, if the bimetal forming the temperature-sensitive deformation members 13, 23, 33 is a bimetal composed of the high expansion portion 17 and the low expansion portion 15 formed on the surface of the high expansion portion 17 facing the lower surface of the package 11. Good.

  In the above-described embodiment, the temperature-sensitive deformation members 13, 23, and 33 are arranged on the lower surface side of the package 11, but the electronic device 40 illustrated as an example corresponding to the first embodiment in FIG. In addition, the temperature-sensitive deformation member may be disposed on the upper surface side of the package 11. Also in this case, the positions of the low expansion portion 15 and the high expansion portion 17 may be appropriately exchanged according to the warping direction when the package 11 is heated.

  As described above, by arranging the temperature-sensitive deformation member on the upper surface side of the package 11, it is possible to increase the area where the solder bump can be formed, and to prevent interference between the temperature-sensitive deformation member and the wiring board. Can do.

  Further, the temperature-sensitive deformation members 13, 23, and 33 may be disposed on both the upper surface and the lower surface of the package 11. In this case, it is preferable to arrange the low expansion part 15 and the high expansion part 17 so that the temperature-sensitive deformation members 13, 23, 33 arranged above and below warp convexly in the same direction.

  Invar alloy is used as the material for the low expansion portion 15 and copper is used as the material for the high expansion portion 17. However, these are merely examples. For example, instead of copper, Ni—Cr is used as the material for the high expansion portion 17. -Fe alloy may be used.

  In the above-described embodiment, the plurality of temperature-sensitive deformation members 13, 23, and 33 are disposed. However, at least one of the temperature-sensitive deformation members 13, 23, and 33 may be disposed. If at least one temperature-sensitive deformation member 13, 23, 33 is arranged, it is possible to reduce deformation of the package around the at least one temperature-sensitive deformation member 13, 23, 33.

  In the above-described embodiment, a bimetal composed of two layers is used as the temperature-sensitive deformable member, but a member obtained by laminating three or more layers of metal deformed by heating may be used.

  In the above embodiment, the rising portions 13B, 23B, 33B of the temperature-sensitive deformation members 13, 23, 33 may be formed of a member other than the bimetal. Also, the temperature-sensitive deformation members 13, 23, 33 are. You may consist only of base part 13A, 23A, 33A. In that case, both end portions of the base portions 13A, 23A, and 33A may be fixed to the package 11 with an adhesive or the like.

  Note that the present invention can be applied to various packages or substrate structures subjected to heat treatment.

  Various materials, configurations, shapes, arrangements, and the like in the above-described embodiments are merely examples, and can be selected as appropriate according to the application. Moreover, the said Example can be combined suitably.

10, 20, 30, 40 Electronic device 11 Package 12 Solder bump 13, 23, 33 Temperature-sensitive deformation member 13A, 23A, 33A Base portion 13B, 23B, 33B Rising portion

Claims (8)

A rectangular plate package;
A temperature-sensitive deformable member that is disposed in at least one of the four corner regions of the package and includes a long flat portion extending in a diagonal direction of the main surface of the package;
An electronic device comprising:
An electronic device characterized in that both ends of the temperature-sensitive deformation member in the longitudinal direction are fixed to the package.   The said temperature-sensitive deformation member has a rising part rising from both ends in the longitudinal direction of the flat part, and the rising part is buried in the package. Electronic devices.   The temperature-sensitive deformation member has a rising portion that rises from only one of both end portions in the longitudinal direction of the flat portion, and the other end portion of the rising portion and the flat portion is buried in the package. The electronic device according to claim 1.   The electronic device according to any one of claims 1 to 3, wherein the temperature-sensitive deformation member bends in a direction opposite to a bending direction when the package is heated when heated. A rectangular plate package;
A temperature-sensitive deformable member that is disposed along each side of the package and includes a long flat portion extending along each side of the package;
An electronic device comprising:
Both ends of the temperature-sensitive deformation member in the longitudinal direction are fixed to the package.   The temperature-sensitive deformable member has a rising portion that rises from both ends in the longitudinal direction of the flat portion, and the rising portion is buried in the package. The electronic device described.   The temperature-sensitive deformation member has a rising portion that rises from both end portions in the short direction of the flat portion, and the other end portion of the rising portion and the flat portion is buried in the package. The electronic device according to claim 5, wherein:   The electronic device according to claim 5, wherein the temperature-sensitive deformation member bends in a direction opposite to a bending direction when the package is heated when heated.

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