JP2004327481A - Circuit device, electronic equipment, and method of manufacturing circuit device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit device provided with a cooling device that can efficiently cool a heat generating element and can be reduced in size, thickness, or weight, and to provide electronic equipment and a method of manufacturing circuit device. <P>SOLUTION: The circuit device is constituted by directly setting up the heat generating element 2 on the surface 15a of the enclosure 15 composed of an electrical insulating material of the cooling device 5 and directly forming conductor lines 3 on the surface 15a. Consequently, the thermal efficiency of the cooling device 5 can be improved, because it is not required to use, for example, the generally used glass epoxy laminate having a low coefficient of thermal conductivity. In addition, the thickness and size of the cooling device 5 can be reduced, because the heat spreader used in the conventional circuit device is not required and no bonding agent etc., is required for attaching the heat spreader to the enclosure 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a circuit device provided with a cooling device having a heat pipe function, an electronic device equipped with the circuit device, and a method of manufacturing the circuit device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a device using a heat pipe has been proposed as a mechanism for cooling a heating element such as a CPU (Central Processing Unit) mounted on a circuit board such as a computer. The heat pipe has a condensable working fluid sealed inside the container. Heat generated from the heat generating element is transmitted to the heat receiving portion of the heat pipe container, and the working fluid evaporates to vapor. When the working fluid becomes steam, the pressure in the vicinity of the heat input section in the container increases, so that the working fluid flows to the side where the pressure in the container is low, that is, to the heat radiating section. When the steam flows to the radiator, the working fluid condenses and releases heat. The condensed working fluid returns to the heat receiving section through a groove provided in the container. The phenomenon in which the working fluid flows through the groove utilizes a capillary phenomenon. In this way, the heat pipe cools the heat generating element by repeating heat reception and heat radiation.
[0003]
In the heat pipe, the container is usually made of metal such as copper or aluminum in order to increase the thermal conductivity. A heating element is attached to the container with a heat spreader (heat diffusion member) interposed therebetween. Further, the container, the heat spreader, and the heat generating element are bonded by an adhesive such as a heat transfer sheet (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-2002-76664 (paragraphs [0020], [0021], etc.)
[0005]
[Problems to be solved by the invention]
However, recently, the amount of heat generation has been increasing with the improvement in the degree of integration of the heating elements. If the heat conductivity of the heat pipe is low, a computer mounted with an element generating a large amount of heat may cause thermal runaway. In order to solve such a problem, there is a method of reducing heat generation by lowering the power of the element. However, in addition to such a method, it is required that the heating elements be cooled more efficiently by using the heat pipe.
[0006]
Further, when the heat pipe container is made of metal, as in the heat dissipation device described in Patent Document 1, there is a problem that heat conductivity is good but the weight is not suitable for weight reduction. Further, in the device described in Patent Literature 1, the thickness of the heat spreader or the like is reduced, but it is still difficult to reduce the size of the device because the thickness (the thickness in the direction W) is still large. Therefore, for example, when the heat radiating device is incorporated in a notebook computer, it is expected that further miniaturization, thinning, and lightening can be achieved.
[0007]
In view of the circumstances as described above, an object of the present invention is to provide a circuit device having a cooling device, which can efficiently cool a heating element, and which can be reduced in size, thickness, or weight. An object of the present invention is to provide a method of manufacturing an apparatus and a circuit device.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a circuit device according to the present invention has a container made of an electrically insulating material in which a working fluid is sealed, and absorbs and discharges heat using an evaporating action and a condensing action of the working fluid. A cooling device, a heating element that is directly installed on the surface of the container and generates heat is absorbed by the cooling device, and a conductor wire that is directly formed on the surface of the container and electrically connected to the heating element. And a circuit unit.
[0009]
In the present invention, the heating element is directly installed on the surface of the container made of the electrically insulating material of the cooling device, and the conductor wire is directly formed on the surface. Thus, for example, if a material having relatively high thermal conductivity is used as the material of the container, the thermal efficiency of the cooling device can be improved. Further, a heat spreader and an adhesive for attaching the heat spreader to a container as in the related art are not required, and the thickness and the size can be reduced.
[0010]
In the present invention, examples of the heating element include a CPU, an MPU (Micro Processing Unit), a memory, a motor, and the like, and any heating element may be used.
[0011]
In one embodiment of the present invention, the container is made of ABS (Acrylonitrile Butadiene Strain), PPS (Poly Phenylene Sulfide), polyimide, polyamide, polyester, silicon nitride ceramics, or aluminum nitride ceramics. This makes it possible to reduce the weight and thickness of the circuit device as compared with the case where the container is made of metal. In particular, the container can be made flexible by using polyimide, polyamide, or polyester. As a result, for example, when a circuit device is mounted on an electronic device, the installation location is less limited, which contributes to size reduction and thickness reduction. On the other hand, by using silicon nitride ceramics, aluminum nitride ceramics, or the like having excellent thermal conductivity, the thermal efficiency of the cooling device can be improved while maintaining the electrical insulation of the container.
[0012]
In one embodiment of the present invention, the container includes a wall having a flat portion at least a part of which is formed as a flat surface, and the circuit portion is provided on the flat portion. By providing the flat portion and providing the circuit portion on the flat portion as described above, the container can be made as thin as possible. Further, since the heating element or the like is directly installed on the flat portion, the heating element is integrated, for example. When it has a flat shape like a circuit chip, the contact area between the container surface and the heating element can be made as large as possible. As a result, the thermal efficiency of the cooling device can be further increased. Further, the shape of the container can be, for example, a flat plate shape. By having a flat plate shape, the cooling device is like a circuit board. That is, the substrate of the circuit unit serves as a cooling device. As a result, for example, when a circuit device is mounted on an electronic device, the thickness of the electronic device can be reduced.
[0013]
In one embodiment of the present invention, the cooling device includes a support provided inside the container and supporting the wall portion from external pressure applied to the flat portion. For example, when the inside of the container is evacuated and the working fluid is sealed therein, atmospheric pressure is applied to the plane portion, and the wall portion of the container may be crushed. In the present invention, such a problem can be avoided by providing a support for supporting the wall from inside the container.
[0014]
In one embodiment of the present invention, the heating element has a motor, the container has a first flat portion formed on a surface of the container in a flat shape and at least the conductor wire is formed, A second flat portion facing the flat portion, and the circuit portion has a magnetic circuit member formed on the second flat portion to configure a magnetic circuit of the motor. Thus, a motor circuit device integrated with the cooling device can be provided. Any magnetic material may be used as the magnetic circuit member. In the present invention, the heat generating element includes a motor and an integrated circuit for driving the motor. This integrated circuit can be installed, for example, on the first plane portion, but is not limited to this.
[0015]
The electronic device according to the present invention has a container made of an electrically insulating material in which a working fluid is sealed, and a cooling device that absorbs and emits heat by using an evaporating action and a condensing action of the working fluid; A heating element is provided directly on the surface, and the generated heat is absorbed by the cooling device, and a circuit section is formed directly on the surface of the container and has a conductor wire electrically connected to the heating element. Circuit device.
[0016]
In the present invention, a heating element is installed on the surface of a container made of an electrically insulating material of a cooling device, and a conductor wire is directly formed on the surface. Thus, for example, if a material having relatively high thermal conductivity is used as the material of the container, the thermal efficiency of the cooling device can be improved. Further, a heat spreader and an adhesive for attaching the heat spreader to a container as in the related art are not required, and the thickness and the size can be reduced. As a result, the electronic device can be made thinner and smaller.
[0017]
The method for manufacturing a circuit device according to the present invention includes: (a) a cooling device that includes a container made of an electrically insulating material in which a working fluid is sealed, and absorbs and discharges heat using an evaporating action and a condensing action of the working fluid. Arranging a device at a predetermined position; (b) directly installing a heating element on the surface of the container of the cooling device arranged at the predetermined position; and (c) electrically connecting the heating element to the container. Forming the connected conductor wire directly on the surface of the container.
[0018]
According to the present invention, for example, if a material having relatively high thermal conductivity is used as the material of the container, the thermal efficiency of the cooling device can be improved. Further, unlike the conventional case, a heat spreader or an adhesive for attaching the heat spreader to a container is not required, so that the number of manufacturing steps can be reduced and the cost can be suppressed. Further, the thickness and the size of the circuit device can be reduced.
[0019]
In the present invention, the predetermined position may be any place where the steps (b) and (c) can be performed. For example, when a conductor line is formed by a photolithography technique or the like, the predetermined position is on a mounting table used in various apparatuses used in a photolithography process or the like.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 is a perspective view showing a circuit device according to a first embodiment of the present invention. 2 and 3 are an AA sectional view and a BB sectional view of the circuit device shown in FIG. 1, respectively. A cooling device 5 is provided in the circuit device 1, and a circuit unit 10 is provided on the cooling device 5. The circuit section 10 has a CPU 2 and other elements 4 such as a capacitor and a resistor as heating elements, and has a circuit wiring 3 as a conductor wire. Generally, the heat value of the CPU 2 is so large that the heat values of the other elements 4 can be ignored.
[0022]
The cooling device 5 has a function of a heat pipe. As shown in FIGS. 2 and 3, the inside 15 b of the container 15 of the cooling device 5 is evacuated, for example, and the working fluid 6 is sealed therein. As the working fluid 6, for example, pure water, methanol, ammonia, chlorofluorocarbon alternative, or the like can be used. The working fluid 6 is located on the right side of the interior 15b of the container 15 in FIG. 2, but if the circuit device 1 is arranged horizontally as shown in the figure, it should actually be located below the interior 15b by gravity. become.
[0023]
The mesh member 7 is attached to the inner wall of the container 15. The mesh member 7 has a function of circulating the working fluid 6 by capillary action. The mesh member 7 is made of, for example, metal, cloth, carbon fiber, or the like. Here, the cloth means a woven fabric, a knitted fabric, a nonwoven fabric, or the like. By using such a cloth, the thermal conductivity can be improved as compared with the case where a metal mesh member is used.
[0024]
The container 15 is formed in a substantially flat plate shape and is made of an electrically insulating material. For example, as the material, ABS, PPS, polyimide, polyamide, polyester, aluminum nitride ceramics, and silicon nitride ceramics are used. Thereby, the weight and thickness of the circuit device can be reduced as compared with the case where the container 15 is made of metal. Specifically, the container 15 can be made flexible by using, for example, polyimide, polyamide, polyester, or the like. As a result, for example, when the circuit device 1 is mounted on an electronic device such as a notebook computer or a PDA (Personal Digital Assistance), the place of installation of the circuit device 1 is reduced, and the electronic device is reduced in size and thickness. On the other hand, by using aluminum nitride ceramics, silicon nitride ceramics, and the like having excellent thermal conductivity, the thermal efficiency of the cooling device can be improved while maintaining the electrical insulation of the container 15. Aluminum nitride ceramics and silicon nitride ceramics have a high thermal conductivity of about 200 to 400 [W / (m · K)].
[0025]
The heating elements 2, 4, etc. of the circuit section 10 are directly attached to the surface 15 a of the container 15. The conductor wire 3 is also formed directly on the surface 15a of the container 15 and wired. The conductor wire 3 can be formed by, for example, a thin film forming technique or a photolithography technique. Specifically, first, as shown in FIG. 4A, a metal film 8 is formed on the surface 15a of the container 15, and as shown in FIG. 4B, a resist film 9 is formed, exposed, and developed. . Then, the excess metal film 8 is removed by etching or the like, and the resist is stripped off as shown in FIG. After forming the conductor wire 3 as described above, for example, the heating element 2 and the like are installed.
[0026]
Next, the operation of the cooling device 5 provided in the circuit device 1 will be described. The heat generated from the heating element 2 is received from the heat receiving unit 20 of the cooling device 5. Specifically, the heat generated from the heating element 2 is transmitted to the surface 15 a of the container 15 in the heat receiving section 20. Strictly, some heat is also generated from the element 4 such as a capacitor or a resistor, so that the heat is also transmitted to the surface 15a and is input.
[0027]
When the working fluid 6 evaporates and becomes vapor due to the heat received by the heat receiving unit 20, the pressure in the vicinity of the heat receiving unit 20 in the container 15 increases. . When the steam flows to the radiator 30, the working fluid 6 condenses and releases heat. The condensed working fluid 6 returns to the heat receiving section 20 through the mesh member 7. In this way, the cooling device 5 cools the heating elements 2 and 4 by repeating heat reception and heat radiation.
[0028]
As described above, in the present embodiment, the heating element 2 is directly installed on the surface 15a of the container 15 made of an electrically insulating material of the cooling device 5, and the conductor wire 3 is directly formed on the surface 15a. Accordingly, for example, it is not necessary to use a generally used glass epoxy laminate having a low thermal conductivity (a thermal conductivity of about 0.35 [W / (m · K)]). Can be improved. Further, unlike the conventional case, there is no need for a heat spreader or an adhesive for attaching the heat spreader to the container 15, and the thickness and the size can be reduced. As a result, the number of manufacturing steps of the circuit device can be reduced, and the cost can be reduced.
[0029]
In the present embodiment, the heating element or the like is directly installed on the flat surface 15a of the container 15, so that the contact area between the surface 15a and the heating elements 2, 4 can be maximized. As a result, the thermal efficiency of the cooling device 5 can be further increased.
[0030]
In the present embodiment, by making the container 15 flat, the cooling device 5 is like a circuit board. That is, the substrate of the circuit unit 10 becomes the cooling device 5. Therefore, for example, when the circuit device 1 is mounted on an electronic device, the thickness of the electronic device can be reduced.
[0031]
FIG. 5 is a perspective view of a circuit device according to the second embodiment of the present invention.
[0032]
The circuit section 31 is provided on the surface 35 a of the container 35 of the cooling device 25. The cooling device 25 has a heat pipe function similarly to the cooling device 5 according to the first embodiment. The circuit unit 31 has, for example, two processing units 22a and 22b. These two processing units 22a and 22b function as, for example, a main CPU and a sub CPU. In this circuit device 21, similarly to the circuit device 1 according to the first embodiment, the heating elements 22a, 22b, and 24 are directly provided on the surface 35a of the container 35, and the conductor wire 23 is also directly provided on the surface 35a. Is formed. The container 35 is also made of an electrical insulating material, for example, ABS, PPS, polyimide, polyamide, polyester, silicon nitride ceramics, and aluminum nitride ceramics. The shape of the container 35 is a flat plate, and is formed wider than the container 15 in the above embodiment.
[0033]
Since the circuit device 21 has the two elements 22a and 22b that generate a large amount of heat, the vicinity of the place where the elements 22a and 22b are installed becomes the heat receiving portion of the cooling device 25, respectively. Therefore, the heat radiating portion is a portion other than the portion where the elements 22a and 22b are installed.
[0034]
As described above, in the present embodiment, the same effects as those of the first embodiment can be obtained, and even when there are a plurality of heating elements such as a CPU having a relatively large heating value, the heating elements can be efficiently cooled. can do.
[0035]
FIG. 6 is a perspective view showing a state in which, for example, a fan motor 33 and a heat sink 34 are attached to the circuit device 21 shown in FIG. Specifically, the heat sink 34 is brought into contact with the heat radiating portion of the container 35 of the cooling device 25. The fan motor 33 is housed in the case 32. The air taken into the case 32 from the outside by the fan motor 33 flows to the heat sink 34 through the opening 32a of the case. Thereby, the heat released from the cooling device 25 is transmitted to the heat sink 34, and the heat stored in the heat sink 34 is efficiently released by the air supplied by the fan motor 33. Thereby, the heating elements 22a and the like are cooled more efficiently.
[0036]
FIG. 7 is a perspective view showing a circuit device according to a third embodiment of the present invention. FIG. 8 is a sectional view taken along the line CC in FIG.
[0037]
The circuit device 41 has a cooling device 45 having a heat pipe function, and a circuit portion including a heating element 42 and other conductor wires (not shown). The heating element 42 is directly attached to the surface 55 a of the container 55 of the cooling device 45. The support body 52 is provided in the inside 55b of the container 55. The support body 52 is provided in a plurality, for example, and has a cylindrical shape. The support 52 is provided in contact with the upper and lower walls 55c of the container 55, and supports the wall 55c from the inside. If the support 52 is not provided, the interior 55b may be deformed, such as dented or crushed by the atmospheric pressure, due to the vacuum inside, but according to the present embodiment, there is no such problem. It is to be noted that if the material of the container 55 can be made of a material that does not deform due to atmospheric pressure, or if the wall has a thickness that does not deform due to atmospheric pressure, the support 52 need not be provided.
[0038]
Next, a fourth embodiment of the present invention will be described. FIG. 9 is a sectional view showing a circuit device for a motor according to the present embodiment.
[0039]
The circuit device 61 is a circuit device for a motor. For example, the motor 80 is a fan motor mounted on a computer or the like. The circuit device 61 has a cooling device 65, and has a circuit portion having a heating element 62, a conductor wire 63, and the like. The heat generating element 62 is, for example, an integrated circuit for driving the fan motor 80, and is directly attached to the surface 75 a of the container 75 of the cooling device 65. The conductor wire 63 is also formed directly on the surface 75a. Further, the magnetic member 71 is directly attached to the front surface 75a (back surface side) of the surface 75a of the container 75 opposite to the side on which the heating element 62 is provided. The magnetic member 71 is, for example, a silicon steel plate, an aluminum plate, or a zinc steel plate. Although not shown, a conducting wire is connected to a coil portion 85 of the motor described later.
[0040]
The coil portion 85 of the fan motor 80 is attached to a support member 86 provided at the center thereof, and the support member 86 is fitted into a hole 75d provided in a container 75 of the cooling device 65 shown in FIG. Fixed. The shaft 83 is attached to a support member 86 via a bearing 84. A blade 81 is fixed to the shaft 83, and a magnet 82 is attached to the blade 81. A magnetic circuit M is formed using the magnetic member 71 by a current flowing through the coil portion 85, and the blade portion 81 is configured to rotate.
[0041]
As shown in FIG. 10, the heat generated by the integrated circuit 62 is received by the heat receiving unit 20 of the cooling device 65 and is radiated by the heat radiating unit 30. The elements that generate heat include not only the integrated circuit 62 but also the coil part 85 of the fan motor 80 in particular. Therefore, the heat generated from the coil portion 85 is also received by the heat receiving portion 20 via the support member 86 and is radiated by the heat radiating portion 30.
[0042]
According to the present embodiment, it is possible to provide a motor circuit device integrated with the cooling device 65, and to efficiently cool not only the chip-shaped integrated circuit 62 but also the motor 80.
[0043]
The present invention is not limited to the embodiments described above, and various modifications are possible.
[0044]
The shape of the container of the cooling device is not limited to the shape described in each of the above embodiments, and may be, for example, a flat plate shape, a triangular shape, an L-shaped shape, a mouth shape, or the like. Further, the cross section of the container may have a substantially elliptical shape obtained by crushing a circular shape, or the shape is not limited to a flat plate shape, and a part of the surface of the container may be a curved surface shape.
[0045]
In the fourth embodiment, the magnetic member 71 does not necessarily have to be attached to the back side of the container, and may be attached to the side where the coil portion 85 is located. The motor is not limited to a fan motor, but may be, for example, a servo motor or a voice coil motor.
[0046]
【The invention's effect】
As described above, according to the present invention, it is possible to efficiently cool the heating element and the like, and to reduce the size, thickness, and weight of the circuit device.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a circuit device according to a first embodiment of the present invention.
FIG. 2 is a sectional view of the circuit device shown in FIG.
FIG. 3 is a sectional view taken along line BB of the circuit device shown in FIG. 1;
FIG. 4 is a view illustrating a process of forming a conductor wire.
FIG. 5 is a perspective view of a circuit device according to a second embodiment of the present invention.
6 is a perspective view showing a state where a fan motor and a heat sink are attached to the circuit device shown in FIG. 5;
FIG. 7 is a perspective view showing a circuit device according to a third embodiment of the present invention.
8 is a sectional view taken along the line CC in FIG. 7;
FIG. 9 is a sectional view showing a circuit device according to a fourth embodiment of the present invention.
FIG. 10 is a perspective view showing a cooling device of the circuit device in FIG. 9;
[Explanation of symbols]
1, 21, 41, 61 ... circuit devices 2, 22a, 22b, 42, 62 ... heating elements 3, 23, 63 ... circuit wiring, conductor wires 5, 25, 45, 65 ... cooling device 6 ... working fluid 10, 31 Circuit parts 15, 35, 55, 75 Containers 15a, 35a, 55a, 75a Surface 15b, 55b Interior 52 Support 55c Wall 71 Magnetic member 80 Motor

Claims (7)

A cooling device that has a container made of an electrically insulating material in which a working fluid is sealed, and that absorbs and emits heat using an evaporating action and a condensing action of the working fluid;
A heating element which is directly installed on the surface of the container and in which generated heat is absorbed by the cooling device, and a circuit section having a conductor wire directly formed on the surface of the container and electrically connected to the heating element. A circuit device comprising: The circuit device according to claim 1, wherein
The circuit device, wherein the container is made of ABS, PPS, polyimide, polyamide, polyester, silicon nitride ceramics, or aluminum nitride ceramics. The circuit device according to claim 1, wherein
The container includes a wall having a flat portion in which at least a part of the surface of the container is formed flat,
A circuit device, wherein the circuit portion is provided on the plane portion. The circuit device according to claim 3, wherein
The said cooling device is a circuit device provided with the support body provided in the inside of the said container, and supporting the said wall part from the external pressure applied to the said flat part. The circuit device according to claim 1, wherein
The heating element has a motor,
The container has a first flat portion formed flat on the surface of the container and at least the conductor wire is formed, and a second flat portion facing the first flat portion,
The circuit device according to claim 1, wherein the circuit portion includes a magnetic circuit member formed on the second plane portion to configure a magnetic circuit of the motor. A cooling device that has a container made of an electrically insulating material in which a working fluid is sealed, and that absorbs and emits heat using an evaporating action and a condensing action of the working fluid;
A circuit part having a heating element directly installed on the surface of the container and absorbing generated heat by the cooling device; and a conductor wire formed directly on the surface of the container and electrically connected to the heating element. An electronic device comprising a circuit device comprising: (A) having a container made of an electrically insulating material in which a working fluid is sealed, and arranging a cooling device at a predetermined position for absorbing and releasing heat by using an evaporating action and a condensing action of the working fluid;
(B) directly installing a heating element on the surface of the container of the cooling device disposed at the predetermined position;
(C) a step of directly forming a conductor wire electrically connected to the heating element on the surface of the container.

Images