JP2015162497A - Semiconductor device and electronic apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which can release generated heat while inhibiting an increase in mounting area.SOLUTION: A semiconductor device comprises: s support medium which has a thickness almost the same with that of a bare chip and is arranged adjacent to the bare chip; a flexible circuit board on which the bare chip and the support medium are mounted and which is folded so as to surround the bare chip and the support medium; a heat release part which is provided by thermal contact with an external surface of the flexible circuit board which surrounds the bare chip and the support medium; and leg parts which pierce the flexible circuit board to conduct heat in a region surrounded by the flexible circuit board to the outside of the region surrounded by the flexible circuit board.

Description

  The present invention relates to a semiconductor device with improved heat dissipation characteristics and an electronic apparatus using the same.

  In order to realize the recent demands for downsizing and low power consumption in electronic devices, high-density mounting of semiconductor devices is required. Japanese Patent Application Laid-Open No. 8-335663 discloses a three-dimensional mounting type semiconductor device having a configuration in which a flexible circuit board on which a bare chip semiconductor element is mounted is bent and the bare chip is wrapped.

  By directly connecting (mounting) the bare chip to the flexible circuit board, the thickness can be reduced, and the outer size of the bare chip and the final semiconductor device can be made substantially the same.

  However, in the configuration according to Japanese Patent Application Laid-Open No. 8-335663, since the bare chip is wrapped with a flexible circuit board, when the power consumption of the bare chip is large, the heat generated in the bare chip is difficult to escape to the outside. turn into. As a result, there is a problem that the temperature of the bare chip rises and malfunctions occur.

  From this point of view, in WO2011 / 043493, the heat dissipation efficiency of the heat generated in the bare chip is improved by wrapping the support together with the bare chip in a flexible circuit board and projecting the support. Semiconductor devices have been proposed.

JP-A-8-335663 WO2011 / 043493

  However, the structure according to WO2011 / 043493 has a problem in that the mounting area of the semiconductor device increases because the support protrudes from the flexible circuit board.

  SUMMARY OF THE INVENTION Accordingly, a main object of the present invention is to provide a semiconductor device and an electronic device using the same that can efficiently dissipate heat generated while suppressing an increase in mounting area.

  In order to solve the above-described problem, a support body that is substantially the same thickness as the bare chip and that is disposed adjacent to the bare chip, the bare chip and the support body are mounted, and are folded so as to enclose the bare chip and the support body. A flexible circuit board, a heat radiation portion provided in thermal contact with the outer surface of the flexible circuit board enclosing the bare chip and the support, and the flexible circuit board inserted through the flexible circuit board And a leg portion for guiding heat in the region surrounded by the flexible circuit board to the outside of the region surrounded by the flexible circuit board.

  According to the present invention, it is possible to efficiently dissipate heat generated while suppressing an increase in mounting area.

1 is a cross-sectional view of a semiconductor device according to a first embodiment. It is a figure explaining the structure of a flexible circuit board, (a) is an expanded view, (b) is a cross-sectional perspective view which shows a mode that a bare chip and a support body are wrapped. It is a figure which shows the opening shape of a support body side opening part. It is the figure which showed the heat conduction path by which the heat | fever from a bare chip is thermally radiated with the arrow. 1A and 1B are diagrams of main elements in a semiconductor device, where FIG. 1A is a side view of a bare chip, FIG. 1B is a top view of a support, FIG. 2C is a cross-sectional view of a flexible circuit board, and FIG. FIG. It is a figure of the flexible circuit board by which the bare chip etc. were temporarily mounted, (a) is a side view, (b) is a top view. FIG. 3 is a cross-sectional view of a package formed by wrapping a bare chip and a support with a flexible circuit board and bonding them to each other. It is sectional drawing of the package soldered with the solder ball. It is sectional drawing of the semiconductor device which concerns on 2nd Embodiment. It is sectional drawing of the semiconductor device which concerns on 3rd Embodiment. It is sectional drawing of the semiconductor device of another structure. It is sectional drawing of the semiconductor device of another structure. It is sectional drawing of the semiconductor device which concerns on 4th Embodiment. It is sectional drawing of the semiconductor device which laminated | stacked two bare chips.

<First Embodiment>
A first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of a semiconductor device 2A according to the present embodiment. The semiconductor device 2A should be used in electronic devices with high demands for miniaturization and high integration, such as home game machines, medical devices, workstations, servers, personal computers, car navigation systems, mobile phones, robots, and measuring instruments. Can do.

  Such a semiconductor device 2 </ b> A includes the element unit 4 and the heat dissipation unit 6 as main components, and is used by being mounted on the mounting substrate 10.

  The element unit 4 includes a bare chip 11, a support body 12, and a flexible circuit board 13. The bare chip 11 and the support 12 are mounted on the flexible circuit board 13 and are wrapped by the flexible circuit board 13. That is, the element portion 4 is in a bag state in which the bare chip 11 and the support 12 are wrapped by the flexible circuit board 13.

  Therefore, the outer surface of the flexible circuit board 13 in the bag state (the surface on the heat dissipating material 21 side in FIG. 1) is referred to as a heat dissipating side surface Fh, and the other outer surface (the surface on the mounting substrate 10 side in FIG. 1) is the terminal side surface. Described as Ft. Moreover, the back surface (surface on which the bare chip 11 is mounted) of the terminal side surface Ft is referred to as a chip mounting surface Fc.

  Examples of the bare chip 11 include semiconductor ICs, packaged electronic components, passive components such as capacitors, resistors, and inductors.

  The support 12 is formed to have substantially the same thickness as that of the bare chip 11 and prevents an excessive load from being applied to the edge of the bare chip 11. Examples of the material of the support 12 include metals (iron, aluminum, alloys containing aluminum, alloys containing Ni and Fe, alloys containing Ni and Cr, alloys containing Cr, copper), silicon, and the like. Resin materials (nylon, PP, epoxy resin, carbon, aramid resin), mica (mica), etc. can be used.

  The flexible circuit board 13 is a wiring board made of a flexible printed board or the like, and a bare chip connection electrode (not shown) for electrical connection with the bare chip 11 is formed on the chip mounting surface Fc. An external terminal electrode (not shown) for electrical connection with the external terminal 14 is formed on the terminal side surface Ft opposite to the Fc.

  The external terminal 14 is a terminal used for connection to the mounting substrate 10, and for example, a so-called solder ball made of a metal material containing Sn is preferable. Needless to say, the shape is not limited to solder balls, and needless to say, any shape can be used as long as the shape is a surface-mounted component.

  2A and 2B are diagrams illustrating the configuration of the flexible circuit board 13. FIG. 2A is a development view of the flexible circuit board 13, and FIG. 2B is a diagram of the flexible circuit board 13 in which the bare chip 11 and the support 12 are connected. It is a cross-sectional perspective view which shows a mode that it wraps. In FIG. 2A, the bare chip 11 and the support 12 are indicated by dotted lines. The bare chip 11 is mounted substantially at the center of the flexible circuit board 13, and a support 12 is disposed so as to surround the bare chip 11.

  The flexible circuit board 13 is provided with a support side opening 15a. The support side opening 15a is positioned directly above the support 12 when the flexible circuit board 13 is bent and the bare chip 11 and the support 12 are wrapped. However, the area of the support-side opening 15a is appropriately smaller than the area of the opposing support 12. Therefore, when the flexible circuit board 13 is put into a bag state, only the region near the outer peripheral portion of the support 12 is covered with the flexible circuit board 13.

  The shape of the support-side opening 15a is not limited to a rectangular shape, and may be, for example, an elliptical shape as shown in FIG.

  Next, the heat radiation part 6 will be described. The heat dissipation part 6 includes a heat dissipation material 21 and a heat conductive sheet 22.

  The heat dissipation material 21 includes a leg portion 23 and a heat dissipation portion 24. A so-called heat sink can be used as the heat dissipating material 21, but a heat conducting sheet, a heat conducting rubber, or a housing covering the semiconductor device 2 </ b> A can also be used. In the following description, a heat sink is assumed. Moreover, the leg part 23 and the heat radiating part 24 do not need to be a single body, and at least both of them are in close contact with each other, and it is a requirement that no thermal resistance is generated on the contact surface (so that the thermal resistance is small). In the following, it is assumed that the leg portion 23 and the heat radiating portion 24 are separate objects.

  The leg portion 23 is erected on the heat radiating portion 24 of the sheet-like member, and the open end thereof is in close contact with the support body 12 through the support body side opening 15a. Therefore, the heat of the support 12 is efficiently conducted to the heat radiating portion 24 through the leg portion 23. The heat flowing into the heat radiating section 24 is efficiently radiated to the surrounding atmosphere and members such as the atmosphere.

  The heat conducting sheet 22 is a sheet-like member provided in close contact with the heat radiating portion 24. The heat conducting sheet 22 and the heat radiating part 24 are in close surface contact. For this reason, the heat conduction path between the heat radiating section 24 and the heat conducting sheet 22 is uniform and shortest so that the heat of the heat conducting sheet 22 can be efficiently transmitted to the heat radiating section 24.

  FIG. 4 is a diagram showing a heat conduction path through which heat from the bare chip 11 is dissipated by arrows. The heat generated in the bare chip 11 is transmitted to the flexible circuit board 13 in contact with the front and back of the bare chip 11. Thereafter, part of the heat of the flexible circuit board 13 is transmitted to the heat radiating portion 24 via the heat conducting sheet 22 and is radiated to the atmosphere or the like. On the other hand, the remaining heat of the flexible circuit board 13 is transferred to the support 12. Since the leg portion 23 is in close contact with the support 12, the heat from the flexible circuit board 13 is transmitted to the heat radiating portion 24 through the leg portion 23 and is radiated.

  Next, a method for manufacturing the above-described semiconductor device 2A will be described.

  5A and 5B are diagrams of main elements in the semiconductor device 2A, where FIG. 5A is a side view of the bare chip 11, FIG. 5B is a top view of the support 12, and FIG. 5C is a cross-sectional view of the flexible circuit board 13. d) is a top view of the flexible circuit board 13; In addition, the outer size of the bare chip 11 is about 13 mm × 13 mm × height 0.7 mm, and the outer size of the support 12 is about 23 mm × 17 mm × thickness 0.7 mm. The flexible circuit board 13 has an outer size of about 17 mm × 36 mm × thickness 0.14 mm. As the flexible circuit board 13, for example, a board having two wiring layers including the first insulating layer 13a, the second insulating layer 13b, and the third insulating layer 13c as shown in FIG. 5C is used. I get out. The external terminal 14 uses about 100 SnAgCu solder balls having a diameter of about 0.8 mm. The size of the bare chip 11 and the like, the number of layers of the flexible circuit board 13, and the number of external terminals 14 are examples.

  At this time, heat having a thickness of about 25 μm is used as an adhesive layer on the surface R of the support 12 or the surface of the bare chip 11 (see FIG. 5B) on the chip mounting surface Fc of the flexible circuit board 13. A plastic adhesive sheet 13d (adhesion temperature is about 150 ° C.) is pasted.

  Using such a material, first, flux or cream solder is applied to the bare chip connection electrode 13e on the chip mounting surface Fc of the flexible circuit board 13, and the bare chip 11 or the bare chip mounter is used by using a flip bare chip mounting mounter or a bare chip mounter. The support 12 is temporarily mounted as shown in FIG. 6A and 6B are diagrams of the flexible circuit board 13 on which the bare chip 11 and the like are temporarily mounted. FIG. 6A is a side view and FIG. 6B is a top view.

  Next, the flexible circuit board 13 on which the bare chip 11 and the like are temporarily mounted is sucked and fixed onto a heater stage heated to 180 ° C. In this state, the flexible circuit board 13 is bent at a side K (see FIG. 6B) using a pressure tool, and is bonded to the surfaces of the bare chip 11 and the support 12. Thereby, the flexible circuit board 13 wraps the bare chip 11 and the support 12 and adheres to them. FIG. 7 is a cross-sectional view of the package thus formed.

  Thereafter, a solder ball was temporarily mounted on the external terminal 14 on the terminal side surface Ft of the flexible circuit board 13 with a flux, and then placed in a reflow furnace to perform solder connection. FIG. 8 is a cross-sectional view of a package soldered with solder balls.

  Next, the heat conductive sheet 22 is disposed, and the support 12 and the heat radiating part 24 that are visible from the support-side opening 15a in the flexible circuit board 13 are brought into contact with each other.

  Then, the semiconductor device 2A was mounted on the mounting substrate 10 by a mounter, and these semiconductor devices 2A were soldered to the mounting substrate 10 using a reflow device.

  It is noted that the above manufacturing method is an example. Accordingly, it goes without saying that many more modifications can be made without departing from the spirit of the invention.

  As described above, the support 12 exposed to the support-side opening 15a of the flexible circuit board 13 can be thermally conducted to the heat dissipation part 24 via the leg 23, and the bare chip 11 The heat generated in can be efficiently dissipated. An improvement in heat dissipation means that an increase in mounting area can be suppressed and high-density mounting is possible.

Second Embodiment
Next, a second embodiment of the present invention will be described. In addition, about 1st Embodiment and the same structure, the description is abbreviate | omitted suitably using the same code.

  In the first embodiment, the leg portion 23 is configured to be in thermal contact with only the support 12. However, the present invention is not limited to this. For example, as shown in FIG. 9, the bare chip 11 may be in thermal contact. In FIG. 9, the heat conducting sheet is not shown.

  The semiconductor device 2B shown in FIG. 9 opens the area of the flexible circuit board 13 facing the bare chip 11 to form the bare chip side opening 15b, and the leg 25 corresponding to the bare chip side opening 15b. It is additionally provided.

  Thereby, since the heat of the bare chip 11 is also radiated from the leg portion 25, in addition to the effects described so far, the heat radiation efficiency is further improved.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. In addition, about the same structure as embodiment mentioned above, description is abbreviate | omitted suitably using the same code | symbol. In each of the embodiments so far, in order to improve the heat radiation efficiency, the configuration in which the leg portions 23 and 25 are provided to guide the heat of the bare chip 11 to the heat radiation portion 24 has been described. However, the present invention is not limited to such a configuration. For example, as shown in FIG. 10, heat may be caused to flow to the mounting substrate 10 via the leg portions 23.

  As shown in FIG. 11, a semiconductor device 2D having a configuration in which only the bare chip side opening 15b facing the bare chip 11 is provided on the flexible circuit board 13 may be used. Further, as shown in FIG. 12, the semiconductor device 2 </ b> E may be configured such that the support circuit side opening 15 a and the bare chip side opening 15 b are provided in the flexible circuit board 13 and the legs 23 and 25 radiate heat.

  The semiconductor devices 2 </ b> C to 2 </ b> E illustrated in FIGS. 10 to 12 have a configuration in which the mounting substrate 10 also serves as a heat dissipation function of the heat dissipation unit 24. As a result, in addition to the effects described so far, the heat generated by the bare chip 11 can be efficiently radiated to the outside without increasing the height of the semiconductor device.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described. In addition, about the same structure as embodiment mentioned above, description is abbreviate | omitted suitably using the same code | symbol.

  In the semiconductor device described so far, the leg portions 23 and 25 are provided on either the heat radiating portion 24 side or the mounting substrate 10 side. On the other hand, in the present embodiment, the leg portions are provided on both the heat radiating portion 24 side and the mounting substrate 10 side. FIG. 13 is a cross-sectional view of the semiconductor device 2F having such a configuration.

  In the semiconductor device 2 </ b> F, leg portions 23 are provided on the upper and lower sides of the support 12, and the heat radiating portion 24 and the mounting substrate 10 are in thermal contact with the leg portions 23. Therefore, in addition to the effects described so far, the heat dissipation efficiency due to the increase of the heat dissipation path is improved.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described. In addition, about the same structure as embodiment mentioned above, description is abbreviate | omitted suitably using the same code | symbol.

  In each of the embodiments described above, the semiconductor device has a configuration including one bare chip. However, the present invention is not limited to such a configuration. That is, a plurality of bare chips may be included. At this time, the bare chips may be of the same type or different types.

  FIG. 14 is a cross-sectional view of a semiconductor device 2G in which two bare chips 11a and 11b are stacked. That is, the semiconductor device 2G has a structure in which the semiconductor device 2C according to the third embodiment is disposed below the semiconductor device 2A according to the first embodiment and these are mounted on the mounting substrate 10.

  At this time, the semiconductor device 2 </ b> A and the semiconductor device 2 </ b> C are electrically connected by the external terminal 14, and signals to the semiconductor devices 2 </ b> A and 2 </ b> C are performed via the mounting substrate 10.

  As described above, by stacking a plurality of chips, a semiconductor device having excellent heat dissipation efficiency can be obtained while suppressing an increase in mounting area.

  Note that the semiconductor device 2G illustrated in FIG. 14 has a structure in which the semiconductor device 2A and the semiconductor device 2C are stacked, but it is added that the semiconductor device to be stacked is not limited.

2A to 2G Semiconductor device 4 Element part 6 Heat radiation part 10 Mounting board 11, 11a, 11b Bare chip 12 Support body 13 Flexible circuit board 15a Support body side opening part 15b Bare chip side opening part 21 Heat radiation material 22 Heat conduction sheet 23 Leg part 24 Heat radiation Part 25 Leg

Claims (10)

A semiconductor device comprising a bare chip mounted on a mounting substrate,
A support having a thickness substantially the same as that of the bare chip and disposed adjacent to the bare chip;
A flexible circuit board on which the bare chip and the support are mounted and bent so as to wrap the bare chip and the support;
A heat dissipating part provided in thermal contact with the outer surface of the flexible circuit board enclosing the bare chip and the support;
Legs that pass through the flexible circuit board and guide the heat in the area surrounded by the flexible circuit board to the outside of the area surrounded by the flexible circuit board;
A semiconductor device comprising: The semiconductor device according to claim 1,
A region on the heat radiation portion side of the flexible circuit board facing the support is opened, and the leg portion is inserted through the opening to thermally connect the support and the heat dissipation portion. A semiconductor device. The semiconductor device according to claim 1,
An area on the mounting board side of the flexible circuit board facing the support is opened, and the leg portion is inserted through the opening to thermally connect the support and the mounting board. A semiconductor device. The semiconductor device according to claim 1,
A region on the heat radiation part side of the flexible circuit board facing the bare chip is opened, and the leg part is inserted through the opening to thermally connect the bare chip and the heat radiation part. Semiconductor device. The semiconductor device according to claim 1,
A region on the heat radiation part side of the flexible circuit board facing the bare chip is opened, and the leg part is inserted through the opening to thermally connect the bare chip and the heat radiation part. Semiconductor device. A semiconductor device according to any one of claims 1 to 5,
The semiconductor device is characterized in that the opening is formed in at least one of a rectangular shape, an elliptical shape, and a circular shape. The semiconductor device according to claim 1, wherein:
A semiconductor device, wherein a plurality of the flexible circuit boards that wrap around the bare chip and the support are stacked and mounted on the mounting board. A semiconductor device according to any one of claims 1 to 7,
The support may be any one of Fe, an alloy containing Ni and Fe, aluminum, an alloy containing aluminum, copper, an alloy containing Ni and Cr, an alloy containing Cr, silicon, a resin material, mica, and mica. A semiconductor device comprising one material. A semiconductor device according to any one of claims 1 to 8,
The bare chip includes one of a semiconductor IC, a packaged electronic component, a capacitor, a resistor, and an inductor.   An electronic device in which the semiconductor device according to claim 1 is mounted.

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