JP2006237103A - Thermally conductive member and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat dissipation member suitable for constituting an electronic apparatus which seals electronic parts, such as an optical semiconductor element, etc. airtightly, and also to provide the electronic apparatus using this. <P>SOLUTION: The first substrate 1 which forms a plurality of protruded parts 1a on a principal surface, and the second substrate 2 which forms a plurality of recesses 2a on the principal surface are brought into direct contact with each other with the main surface located between the protruded parts 1a of the first substrate 1 so that the protruded part 1a is inserted into the recess 2a, and the main surface located between the recesses 2a of the second substrate 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat conducting member that mounts an electronic component such as an optical semiconductor element and also radiates heat generated from the electronic component satisfactorily, and an electronic device using the same.

  FIG. 3 is a cross-sectional view of an optical semiconductor device for housing optical semiconductor elements such as LD (laser diode) and PD (photodiode) used in the conventional optical communication field.

  The conventional optical semiconductor device includes a base 21a having a shape obtained by vertically cutting a column for mounting the optical semiconductor element S ′ and the circuit board 24 at the center of the upper surface, and the periphery of the base 21a from the upper surface to the lower surface. A disk-shaped metal substrate 21 having a formed through hole 21b and made of a metal such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy, an Fe-Ni alloy, or cold rolled steel (SPC); The through hole 21b is inserted through the sealing material 22 so that at least the lower end portion protrudes from the through hole 21b, and the upper end portion is electrically connected to the circuit conductor of the circuit board 24. And lead terminals 23 made of a metal such as Fe—Ni—Co alloy or Fe—Ni alloy to be connected.

  The metal substrate 21 and the lead terminal 23 are joined through a sealing material 22 made of insulating glass, and the metal substrate 21 and the lead terminal 23 are electrically insulated by the sealing material 22. Further, the optical semiconductor element S ′ has a low melting point such as gold (Au) -tin (Sn) having a melting point of 200 to 400 ° C. directly on the base 21a or via the submount substrate or the circuit board 24 on the base 21a. The electrode of the optical semiconductor element S ′ is electrically connected to the circuit conductor of the circuit board 24 through bonding wires.

  On the upper surface of the metal substrate 21, a first lid 25 made of an Fe-Ni-Co alloy or the like is provided on the outer peripheral portion within a width of 1 mm from the outer peripheral end for the purpose of protecting the optical semiconductor element S '. The second lid body 26 is fixed by welding, seam welding, brazing, or the like, and is further joined by welding such as YAG laser or seam welding, for example, to the portion facing the optical semiconductor element S ′. Thus, it becomes an optical semiconductor device as a product.

  Such an optical semiconductor device is mainly used for large-capacity optical communication, etc., and a lead terminal 23 is connected to an external electric circuit (not shown), and a drive signal is supplied from the external electric circuit, thereby providing an optical semiconductor element. S ′ is optically pumped, and the pumped light is sent to the optical fiber 27 via an optical isolator (not shown) for preventing return light, and is transmitted into the optical fiber 27. It is widely used for transmission capacity of 2.5 Gbps (Gigabit per second) or less at a transmission distance of 40 km or less.

  However, as the demand for high-speed communication at a transmission distance of 40 km or less has increased rapidly in recent years, the transmission capacity has become insufficient, and research and development for further increasing the speed of optical semiconductor devices has been actively promoted. It was. For this purpose, the optical semiconductor element S ′ that transmits an optical signal is driven by a high-frequency signal of about 10 Gbps, and in order to obtain a sufficient signal waveform even in long-distance transmission, the optical semiconductor element S ′ is driven by a higher-power signal. It has been considered to make it output.

The optical semiconductor element S ′ of the conventional optical semiconductor device is driven at about 5 mW, and its optical output is about 0.2 to 0.5 mW. However, in recent high-output optical semiconductor devices, the optical output has been improved to a level of 1 mW, and accordingly, the optical semiconductor element S ′ has been driven with electric power of 10 mW or more. Since the optical semiconductor element S ′ generates a great amount of heat in order to drive the optical semiconductor element S ′ with a large electric power, more effective heat dissipation has been required for the optical semiconductor device. . Therefore, the metal substrate 21 is composed of a heat conductive member made of a metal material such as copper (Cu) -tungsten (W) having excellent heat conductivity and effectively dissipates heat generated by the optical semiconductor element S ′. Proposed.
JP 2000-353846 A

  However, in the conventional optical semiconductor device using the heat conducting member, the heat generated when the first and second lids 25 and 26 are welded to the heat conducting member is transmitted through the optical semiconductor element S ′ through the heat conducting member. Therefore, there is a problem in that the optical semiconductor element S ′ is deteriorated and sufficient performance cannot be obtained.

  In addition, the back surface of the metal substrate 31 made of a metal such as Fe-Ni-Co alloy, Fe-Ni alloy, or SPC as shown in FIG. There is also a method of improving heat dissipation by forming a heat dissipation plate 32 having excellent heat conductivity, such as copper or copper-tungsten, for example.

  However, as shown in FIG. 4, the metal substrate 31 and the heat radiating plate 32 are bonded via a bonding material 33, and the heat conductivity of the bonding material 33 is generally that of the heat radiating plate 32 such as copper or copper-tungsten. Since it is lower than the thermal conductivity, even if the heat radiating plate 32 itself has a high heat radiating property, the thermal conductivity of the heat conducting member formed by joining the metal substrate 31 and the heat radiating plate 32 becomes low, and sufficient There was a problem that heat dissipation could not be obtained.

  The present invention has been completed in view of the above-described conventional problems, and an object of the present invention is to constitute an electronic device that is excellent in heat dissipation and can hermetically seal electronic components such as an optical semiconductor element. An object of the present invention is to provide a heat dissipating member suitable for the purpose and an electronic device using the same.

  In the heat conducting member of the present invention, the first substrate having a plurality of convex portions formed on the main surface and the second substrate having a plurality of concave portions formed on the main surface are inserted into the concave portions. The main surface located between the convex portions of the first substrate and the main surface located between the concave portions of the second substrate are directly brought into contact with each other.

  The heat conducting member of the present invention is characterized in that the tip end portion of the convex portion and the bottom portion of the concave portion are joined via a joining material.

  In the heat conductive member of the present invention, preferably, the bonding material is inserted into a gap between a side surface of the convex portion and a side surface of the concave portion.

  In the heat conducting member of the present invention, preferably, the width of the concave portion is made smaller than the interval between the adjacent concave portions.

  In the heat conductive member of the present invention, preferably, one of the first and second substrates is provided with an electronic component mounting portion, and the heat conductivity of the other substrate is larger than that of the one substrate. It is characterized by that.

  In the heat conducting member of the present invention, preferably, one of the first and second substrates is provided with an electronic component mounting portion, and the thermal expansion coefficient of the one substrate is smaller than that of the other substrate. It is characterized by that.

  The electronic device of the present invention is characterized in that an electronic component is mounted on the heat conducting member of the present invention, and a lid is provided so as to cover the electronic component.

  In the heat conducting member of the present invention, the first substrate having a plurality of convex portions formed on the main surface and the second substrate having a plurality of concave portions formed on the main surface are inserted into the concave portions. Since the main surface located between the convex portions of the first substrate and the main surface located between the concave portions of the second substrate are brought into direct contact, the first and second of different materials By adopting a configuration in which the substrates are intricate with each other, even if a difference in thermal expansion occurs, it is possible to effectively prevent the occurrence of warpage and distortion due to mutual restraint, and increase the bonding reliability. Furthermore, the heat conduction path from one board to the other board is configured as a path with good thermal conductivity by passing through the contact portion between these boards without using a bonding material having low heat conductivity. The heat dissipation is very good.

  As a result of the above, when joining an electronic component or other member having a small thermal expansion coefficient, the material of one of the first and second substrates is made suitable for joining the electronic component or other member. In such a case, no heat damage can be maintained and high heat dissipation can be maintained. For example, a heat conducting member suitable for an electronic device or the like for housing an electronic component that generates heat can be obtained.

  Since the heat conductive member of the present invention joins the tip part of the convex part and the bottom part of the concave part via a joining material, it is very heat conductive via the contact part between the first substrate and the second substrate. The first and second substrates can be firmly bonded to each other with the bonding material while maintaining a good path, and the contact between the first and second substrates can be maintained over a long period of time. In addition, the bonding material can effectively relieve the stress due to the difference in thermal expansion coefficient between the first and second substrates and effectively prevent the first and second substrates from being separated from each other.

  In the heat conducting member of the present invention, since the bonding material is inserted into the gap between the side surface of the convex portion and the side surface of the concave portion, the bonding area between the first and second substrates can be increased to increase the bonding strength. In addition, the cavity can be reduced and the thermal conductivity can be further increased.

  Since the heat conductive member of the present invention has the width of the concave portion smaller than the interval between the adjacent concave portions, the contact area between the first substrate and the second substrate can be increased, and the second Since the cross-sectional area of the substrate can be increased, the thermal conductivity can be further increased.

  The heat conducting member of the present invention is provided with an electronic component mounting portion on one of the first and second substrates, and the thermal conductivity of the other substrate is larger than that of the one substrate. After mounting a component on one substrate, when welding a lid for hermetically sealing an electronic component to one substrate, heat from the welding can be more effectively transferred to the other substrate, It is possible to effectively prevent the electronic component from being deteriorated due to heat transmitted to the electronic component through the one substrate.

  The heat conducting member of the present invention is provided with the electronic component mounting portion on one of the first and second substrates, and the thermal expansion coefficient of one substrate is smaller than that of the other substrate. It is possible to effectively prevent the deterioration of characteristics due to the stress generated in the electronic component to be mounted while suppressing the thermal expansion of the conductive member. Moreover, if the width of the convex portion and the width of the concave portion are the same, the first and second substrates can be joined by caulking due to a difference in thermal expansion, and can be joined without using any joining material. Therefore, the area of the first and second substrates in direct contact with each other can be increased, and a structure with higher heat dissipation can be obtained.

  The electronic device according to the present invention mounts the electronic component on the heat conducting member of the present invention and has a lid so as to cover the electronic component. Therefore, the electronic component housed inside can be radiated well. At the same time, the electronic component can be hermetically sealed for a long time.

  Next, a heat conductive member and an electronic device using the same according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of a heat conducting member of the present invention. FIG. 2 is a cross-sectional view showing an example of an embodiment of the electronic device of the present invention.

  In FIG. 1, 1 is a first substrate, 2 is a second substrate, 3 is a bonding material, and A is a heat conducting member. In FIG. 2, reference numeral 7 denotes a lid, and S denotes an electronic component that generates heat by the operation of an optical semiconductor element or the like.

  The heat conducting member A of the present invention has a first substrate 1 having a plurality of convex portions 1a formed on the main surface and a second substrate 2 having a plurality of concave portions 2a formed on the main surface. The main surface located between the convex portions 1a of the first substrate 1 and the main surface located between the concave portions 2a of the second substrate 2 are brought into direct contact with each other. Then, an electronic component S is mounted on the heat conducting member A, and the lid 7 is attached so as to cover the electronic component S, whereby the electronic device of the present invention is obtained.

  The contact between the main surface located between the convex portions 1a of the first substrate 1 and the main surface located between the concave portions 2a of the second substrate 2 may be surface contact. This increases the contact area and improves thermal conductivity.

  The heat conducting member A of the present invention has a configuration in which the first and second substrates 1 and 2 made of different materials are intricately arranged, so that even if a difference in thermal expansion occurs, they are constrained to each other and warp and distortion occur. Can be effectively prevented and the bonding reliability can be improved. Furthermore, the heat conduction path from one board to the other board is configured as a path with good thermal conductivity by passing through the contact portion between these boards without using a bonding material having low heat conductivity. The heat dissipation is very good.

  Since other members such as the electronic component S and the lid 7 are attached to one of the first and second substrates 1 and 2 (first substrate 1 in FIG. 2), its thermal expansion coefficient For example, Fe-Ni-Co alloy, Fe-Ni alloy, cold rolled steel (SPC), molybdenum (Mo) and other metals, aluminum oxide sintered bodies and aluminum nitride sintered bodies Materials such as ceramics are used.

  Also, the other one of the first and second substrates 1 and 2 (second substrate 2 in FIG. 2) has a high thermal conductivity in order to conduct heat well, for example, copper Or a metal such as copper-tungsten.

  The shape of the convex portion 1a may be a columnar shape, a polygonal columnar shape, a conical shape, a polygonal pyramid shape, or the like, or may be a wall shape continuous in a straight line or a curved shape. Moreover, it is good for the recessed part 2a to make it the shape corresponding to the convex part 1a, for example, column shape, polygonal column shape, reverse cone shape, reverse polygon cone shape, groove shape etc. are mentioned.

  Such convex portions 1a and concave portions 2a are formed by etching or cutting a metal plate.

  The first and second substrates 1 and 2 are formed so that the convex portion 1a is inserted into the concave portion 2a, and the main surface located between the convex portions 1a of the first substrate 1 and the second substrate 2 As long as the main surface located between the recessed parts 2a is made to contact directly, you may join how.

  For example, you may join the front-end | tip part of the convex part 1a, and the bottom part of the recessed part 2a via the bonding | jointing material 3. FIG. In this case, it is preferable to have a gap for the bonding material 3 between the tip of the convex portion 1a and the concave portion 2a (for example, the height of the convex portion 1a is made smaller than the depth of the concave portion 2a). ). Thus, when the front-end | tip part of the convex part 1a and the bottom part of the recessed part 2a are joined via the joining material 3, it is very heat conductive via the contact part of the 1st board | substrate 1 and the 2nd board | substrate 2. While maintaining a good path, the first and second substrates 1 and 2 can be firmly bonded with the bonding material, and the contact between the first and second substrates 1 and 2 can be maintained for a long time. Further, it is possible to effectively prevent the bonding material from peeling off the first and second substrates 1 and 2 by effectively relieving the stress due to the difference in thermal expansion coefficient between the first and second substrates 1 and 2.

  Preferably, the bonding material 3 is inserted into the gap between the side surface of the convex portion 1a and the side surface of the concave portion 2a. Accordingly, the bonding area between the first and second substrates 1 and 2 can be increased to increase the bonding strength, and the cavity can be reduced to further increase the thermal conductivity.

  Alternatively, the convex portion 1a and the concave portion 2a may have substantially the same width, and the first and second substrates 1 and 2 may be joined to each other by meshing the convex portion 1a and the concave portion 2a. In this case, it is not necessary to use a bonding material, and the thermal conductivity can be further improved.

  Further, the first and second substrates 1 and 2 may be joined together by screws or the like. Also in this case, it is not necessary to use a bonding material, and thermal conductivity can be improved.

  Preferably, the width (internal dimension) of the recess 2a is made smaller than the interval between the adjacent recesses 2a. Thereby, the contact area between the first substrate 1 and the second substrate 2 (position between the main surface located between the convex portions 1a of the first substrate 1 and the concave portions 2a of the second substrate 2). The contact area with the main surface to be increased), and the cross-sectional area of the second substrate 2 can be increased, so that the thermal conductivity can be further increased.

  Moreover, it is preferable that the longitudinal elastic modulus of one of the first and second substrates 1 and 2 is set larger than the longitudinal elastic modulus of the other substrate. Thereby, when making the 1st and 2nd board | substrates 1 and 2 contact, the adhesiveness of the contact part of the 1st and 2nd board | substrates 1 and 2 becomes better by deform | transforming the other board | substrate, Further improvement in thermal conductivity can be achieved. In addition, by increasing the longitudinal elastic modulus of one of the substrates, it is possible to effectively prevent the warpage of the heat conducting member A as a whole.

  When the electronic component S is mounted on the heat conducting member A of the present invention and sealed with the lid 7, one of the first and second substrates 1 and 2 (first substrate 1 in FIG. 2). It is preferable to provide a mounting portion for the electronic component S and to make the thermal conductivity of the other substrate (second substrate 2 in FIG. 2) larger than that of the one substrate. Thus, after the electronic component S is mounted on one substrate, when the lid 7 for hermetically sealing the electronic component S is welded to the one substrate, heat from the welding is more effectively transmitted to the other substrate. It is possible to effectively prevent the electronic component S from being deteriorated due to heat transmitted to the electronic component S through one of the substrates.

  Preferably, one of the first and second substrates 1 and 2 (first substrate 1 in FIG. 2) is provided with a mounting portion for the electronic component S, and the thermal expansion coefficient of one substrate is set to the other. It is preferable to make it smaller than the substrate (second substrate 2 in FIG. 2). Thereby, it is possible to effectively prevent the deterioration of characteristics due to the stress generated in the electronic component S to be mounted while suppressing the thermal expansion of the heat conducting member A. Further, if the width of the convex portion 1a and the width of the concave portion 2a are made the same, the joining of the first and second substrates 1 and 2 can be realized by caulking due to the difference in thermal expansion. Since it can join without using at all, the area of the direct contact part of the 1st and 2nd board | substrates 1 and 2 can be enlarged more, and it can be set as a structure with higher heat dissipation.

  The heat conducting member A according to the present invention is used when one of the first and second substrates 1 and 2 is joined when an electronic component S having a small thermal expansion coefficient or another member (for example, the lid 78) is joined. Even if the material is suitable for joining of the electronic component S and other members, damage or the like does not occur, and high heat dissipation can be maintained. For example, for storing the electronic component S having heat generation It can be set as the heat conductive member A suitable for an electronic device etc.

  Next, an electronic device of the present invention using such a heat conducting member A will be described. FIG. 2 is a cross-sectional view showing an example of an embodiment of an electronic device according to the present invention, and shows an example in which an optical semiconductor element is used as an electronic component.

  The electronic device of the present invention has the electronic component S mounted on the heat conducting member A of the present invention, and a lid 7 is provided so as to cover the electronic component S.

  The heat conducting member A is formed with a mounting portion for mounting an electronic component S such as an optical semiconductor element. The electronic component S may be directly mounted on the heat conducting member A, or may be mounted via a submount such as a base 1a made of a metal material or an aluminum nitride sintered body.

  Of the first and second substrates 1 and 2, the thermal conductivity of the substrate on which the electronic component S is mounted (the first substrate 1 in FIG. 2) is the other substrate (the first substrate in FIG. 2). It is better to make it larger than the thermal conductivity of the second substrate 2). Accordingly, after the electronic component S is mounted on the first substrate 1, when the lid body 7 is welded to the first substrate 1, heat from the welding can be more effectively transferred to the second substrate 2. It is possible to effectively prevent heat from being transmitted to the electronic component S through the first substrate 1 and deterioration of the electronic component S.

  The heat conduction member A has a through hole formed around the mounting portion, and a lead terminal 5 made of a metal such as Fe—Ni—Co alloy or Fe—Ni alloy is inserted into the through hole, and at least an end on the lower surface side is inserted. It is fixed via a sealing material 4 made of insulating glass or the like so that the portion protrudes from the through hole.

  Preferably, the thermal expansion coefficient of the board on which electronic component S is mounted (first board 1 in FIG. 2) is made smaller than the thermal expansion coefficient of the other board (second board 2 in FIG. 2). The sealing material 4 is preferably bonded only to the substrate (first substrate 1) on which the electronic component S is mounted. Thereby, even if the heat conductive member A thermally expands, the stress applied to the sealing material 4 can be effectively suppressed, and the occurrence of cracks in the sealing material 4 can be effectively prevented.

  The end of the lead terminal 5 on the electronic component S side is electrically connected to the electronic component S, and an electric signal can be input / output between the electronic component S and the external electric circuit via the lead terminal.

  The electrical connection between the lead terminal 5 and the electronic component S may be made directly via a bonding wire, or by connecting the bonding wire 10 to the circuit board 6 as shown in FIG. You may do it.

  A lid 7 made of Fe-Ni-Co alloy or the like is fixed to the outer peripheral portion of the upper surface of the heat conducting member A by YAG laser welding, seam welding, brazing, or the like for the purpose of protecting the electronic component S. The second lid body 8 having the optical fiber 9 fixed to a portion facing the electronic component S is joined by welding such as YAG laser or seam welding to form an electronic device.

  Note that the present invention is not limited to the above-described best modes and examples, and various modifications may be made without departing from the scope of the present invention. Further, the side surfaces of the convex portion 1a and the concave portion 2a may be perpendicular to the layer direction of the first and second substrates 1 and 2 or may be inclined.

It is sectional drawing which shows an example of embodiment of the heat conductive board | substrate of this invention. It is sectional drawing which shows an example of embodiment of the electronic device of this invention. It is sectional drawing of the conventional electronic device. It is sectional drawing of the conventional heat conductive board | substrate.

Explanation of symbols

1: First substrate 2: Second substrate 3: Bonding material 7: Lid A: Heat conduction member

Claims (7)

A first substrate having a plurality of convex portions formed on the main surface and a second substrate having a plurality of concave portions formed on the main surface, wherein the convex portions are inserted into the concave portions of the first substrate. A heat conduction member, wherein a main surface located between the convex portions and a main surface located between the concave portions of the second substrate are brought into direct contact with each other. The heat conduction member according to claim 1, wherein a tip portion of the convex portion and a bottom portion of the concave portion are joined via a joining material. The heat conductive member according to claim 2, wherein the bonding material is inserted into a gap between a side surface of the convex portion and a side surface of the concave portion. The heat conducting member according to any one of claims 1 to 3, wherein a width of the concave portion is made smaller than an interval between the adjacent concave portions. The electronic component mounting portion is provided on one of the first and second substrates, and the thermal conductivity of the other substrate is larger than that of the one substrate. Item 5. The heat conducting member according to any one of Items 4 to 7. The electronic component mounting portion is provided on one of the first and second substrates, and the thermal expansion coefficient of the one substrate is smaller than that of the other substrate. Item 6. The heat conducting member according to any one of Items 5. An electronic component storage package, wherein an electronic component is mounted on the heat conducting member according to any one of claims 1 to 6, and a lid is provided so as to cover the electronic component.

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