Package for housing electronic component and electronic device

A package 10 includes a housing 1 in which an electronic component 5 is mounted in a recess 1a having an opening on an upper surface and a screwing section 31 that is fixed on a side face of the housing 1 and extends in a lateral direction. The screwing section 31 includes a thin section 34 which is located on a distal end and is provided with a through hole 36 through which a screw is inserted, a thick section 35 which is located between the thin section 34 and the side face of the housing 1 and has a thickness less than that of the side face of the housing 1 and thicker than that of the thin section 34, and a screw fastening hole 37 which extends in the vertical direction in the thick section 35. Even if the housing 1 has warpage when the package 10 is fixed on the external substrate, heat dissipation from the package to the external substrate can be improved.

TECHNICAL FIELD

The present invention relates to a package for housing electronic component and an electronic device.

BACKGROUND ART

A package for housing electronic component (hereinafter, also simply referred to as a package) that houses an electronic component is known, for example, as described in PTL 1. The package described in PTL 1 includes screwing sections at four corners to mount a substrate on an external substrate.

In the package described in PTL 1, a stepped section is formed between a portion of the substrate where a frame is attached and the screwing sections with the upper surface on the screwing section side being lower. The screwing section, which is located distal to the stepped section, has a smaller thickness. Accordingly, the screwing section tends to be deformed when the package is attached to the external substrate.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

However, since the screwing section tends to be deformed, the warpage of the substrate is not easily corrected in the package described in PTL 1. When the substrate is warped upward or downward in an arch, the lower surface of the substrate and the external substrate are not allowed to be in contact with each other by a large contact area. As a result, heat dissipation from the substrate to the external substrate becomes difficult.

The present invention is made in light of the above problem, and an object of the present invention is to provide a package having improved heat dissipation property.

Solution to Problem

A package for housing electronic component according to one embodiment of the present invention includes a housing in which an electronic component is to be mounted in a recess having an opening on an upper surface, and a screwing section that is fixed on a side face of the housing and extends in a lateral direction. The screwing section includes a thin section which is located on a distal end and is provided with a through hole through which a screw is inserted, a thick section which is located between the thin section and the side face of the housing and has a thickness less than that of the side face of the housing in the vertical direction and thicker than that of the thin section in the vertical direction, and a screw fastening hole which extends in the vertical direction in the thick section.

An electronic device according to one embodiment of the present invention includes the package for housing electronic component, an electronic component which is mounted in the recess of the package for housing electronic component, and a cover which is joined to an upper surface of the housing to close the opening.

Advantageous Effects of Invention

According to the package for housing electronic component and the electronic device of one embodiment of the present invention, the screwing section includes a thin section which is provided with a through hole, a thick section which has a thickness less than that of the side face of the housing in the vertical direction and thicker than that of the thin section in the vertical direction, and a screw fastening hole which extends in the vertical direction in the thick section. When the package is screwed down to an external substrate in the thick section, the warpage of the housing is allowed to be easily corrected. As a result, a contact area between the housing and the external substrate increases, which facilitates heat dissipation from the housing to the external substrate.

DESCRIPTION OF EMBODIMENTS

A package for housing electronic component10and an electronic device100according to one embodiment of the present invention will be described with reference to the drawings. All figures are schematic views and are not drawn to scale.

<Configuration of Package for Housing Electronic Component10>

FIG. 1is a perspective view which shows a package for housing electronic component10according to one embodiment of the present invention. As shown inFIGS. 1 to 5, the package for housing electronic component10according to one embodiment of the present invention includes a housing1which has an opening on the upper surface and screwing sections31which laterally extend from the housing1. One end of the screwing section31is fixed on the side face of the housing1. Further, input/output terminals2are fixed on the housing1. The input/output terminals2are provided as part of the housing1. Further, a frame4may be joined around the opening on the upper surface of the housing1.

The screwing section31includes a thin section34which is located on the distal end and is provided with a through hole36through which a screw is inserted, and a thick section35having a thickness larger than that of the thin section34and less than that of the side face of the housing1in the vertical up-down direction. In addition, the thick section35includes a screw fastening hole37in the vertical up-down direction.

The housing1together with the frame4and a cover6hermetically seals an electronic component5. The housing1includes an opening of a recess1aon the upper surface. The electronic component5is mounted in the recess1a. The housing1has a rectangular outer peripheral shape in a plan view. A plurality of notch sections13notched from the upper side is disposed on the side face of the housing1. For example, each notch section13is disposed on three of four sides in a plan view. One notch section13aof three notch sections13(13a,13b,13c), which is disposed on one side at the center between two other sides, is open to the side face and the lower surface, while the notch sections13b,13con the remaining two sides are open to the side face.

Each of the input/output terminals2are attached to each of a plurality of notch sections13. The input/output terminals2are fitted in the notch sections13. Further, the input/output terminals2are joined to the housing1and fixed thereon. The lower surface of the respective input/output terminals2is provided with lead terminals24which extend to the outside. In a case where the notch section13is open to the side face and the lower surface as described above, part of the lead terminals24may be placed inside the outer periphery of the housing1as shown inFIG. 5. This results in the package10reduced in size.

Particularly, when a signal transmitted through the input/output terminals2is high frequency signal, it is required to reduce the transmission distance in order to minimize signal loss. In addition to that, since the lead terminals24perform electrical connection to external devices, connectivity in mounting the package10on an external substrate may be reduced if the length of the lead terminal24itself in the signal transmission direction is not long enough. Accordingly, it is desired to decrease the signal transmission distance while ensuring the length of the lead terminal24. Therefore, it is advantageous to place part of the lead terminal24inside the outer periphery of the housing1. As a result, the signal transmission distance can be decreased while ensuring the length of lead terminal24. For the foregoing reason, the input/output terminal2(2a) for transmitting high frequency signals is provided at the notch section13(13a) which is open to both the side face and the lower surface. Further, the input/output terminals2(2b,2c) for low frequency electric signals used for supplying power or the like are each provided at two notch section13(13b,13c) which are open to the side face.

Since the housing1houses the electronic component5, high insulation property is required. In the housing1, a mounting substrate12having an insulation property is disposed on a metal member11. The metal member11has high heat dissipation property. Accordingly, with the above configuration, the heat dissipation property of the electronic component5may be improved while the insulation property of the electronic component5may also be improved. Further, the electronic component5is mounted on the upper surface of the mounting substrate12.

Specifically, a metal material such as iron, copper, nickel, chrome, cobalt and tungsten may be used as a material of the metal member11. Alternatively, an alloy or composite of those metal materials may be used. The metal member11that forms the housing1may be manufactured by a metal processing method such as rolling and punching of an ingot of those metal materials. The housing1and the screwing section31are integrally formed.

Further, a ceramic material such as aluminum oxide, mullite based, silicon carbide based, aluminum nitride based and silicon nitride based sintered material may be used as a material of the mounting substrate12. Alternatively, a glass ceramic material may be used instead of those ceramic materials.

The input/output terminals2electrically connect the inside and outside of the housing1. The input/output terminals2are fitted in the notch sections13while being partially placed on the lower surface of the housing1. Part of the input/output terminals2extends from the side face of the housing1as seen in a plan view. The input/output terminal2is composed of a wall section25, signal lines and lead terminals24. The wall section25is a cuboid member made of an insulation material and has a step section on the upper surface of a portion located inside of the housing1. The signal lines are provided from the surface of the step section of the wall section25to the lower surface of a portion located outside of the housing1. The lead terminals24are disposed on a portion which is located on the lower surface of the wall section25and outside of the housing1. The lead terminals24are electrically connected to the signal lines. The signal lines of the input/output terminal2exposed on the surface of the step section and the electronic component5are electrically connected to each other. This connection can be established, for example, via a bonding wire. According to the above configuration, electric signals can be transmitted between the electronic component5and the outside of the package10.

A dielectric member having good insulation property is preferably used for the wall section25of the input/output terminal2. For example, a ceramic material such as aluminum oxide based sintered material having a relative dielectric constant in the order of 9.4, mulllite based sintered material having a relative dielectric constant in the order of 7.5, silicon carbide based sintered material having a relative dielectric constant in the order of 40, aluminum nitride based sintered material having a relative dielectric constant in the order of 8.5 and silicon nitride based sintered material having a relative dielectric constant in the order of 9.6, or a glass ceramic material is used for the wall section25. In order to successfully transmit signals via the wiring conductor, the wall section25is made of a material such as the above dielectric materials having a relative dielectric constant in the order of 4 to 50.

The frame4is provided to continuously cover the upper part of the input/output terminals2and the upper part of the housing1. The frame4is a frame-shaped member and has a rectangular inner peripheral shape and outer peripheral shape in a plan view. The frame4is provided along the opening. The frame4is joined to the input/output terminals2and the metal portion11. A metal material such as iron, copper, nickel, chrome, cobalt and tungsten may be used as a material of the frame4. Alternatively, an alloy or composite of those metal materials may be used. The frame4facilitates joining of the cover6.

The screwing sections31fix the housing1on the external substrate. The screwing sections31laterally extend from the housing1. The screwing sections31are disposed at both ends of a side of the housing1where the input/output terminal2(2a) for transmitting high frequency signals is disposed in between.

The screwing section31is a plate member and includes the thin section34and the thick section35. The thin section34is provided with the through hole36through which a screw is inserted. The through hole36is open to the upper surface and the lower surface of the thin section34.

As a dimension of the screwing section, for example, a thickness of the thin section34may be 0.5 to 2 mm and a thickness of the thick section35may be 2.5 to 8 mm. In this case, the thickness of the side face of the housing1is 3 to 10 mm and is larger than that of the thick section35. Further, a diameter of the through hole36may be 1 to 5 mm. The thick section35includes a screw fastening hole37having a diameter of 0.5 to 5 mm.

In the for housing electronic component10, since the screwing section31includes the thin section34having the through hole36, the thick section35having a thickness smaller than that of the side face of the housing1in the vertical (up-down) direction and larger than that of the thin section34in the vertical direction, and the screw fastening hole37which extends in the vertical direction of the thick section35, the warpage of the housing1is corrected and heat dissipation to the external substrate is improved. Specifically, when the through hole36of the package10is attached to the external substrate by using a screw, the thin section34slightly deforms so that the warpage of the housing1is generally corrected along the external substrate while the housing1is fastened to the external substrate.

Then, when the hole37is fastened by using a screw, the warpage of the housing1is further corrected at the proximal end of the screwing section31, the housing1is fastened to the external substrate. The screwing section31is fixed on the external substrate so as to be parallel to the external substrate. Since the warpage of the housing1is corrected and the contact area to the external substrate increases, heat dissipation from the housing1to the outside is improved. Further, since the screwing section31is generally in close fit with the external substrate when fixed on the external substrate, heat dissipation from the screwing section31to the external substrate is also improved.

Further, since the thick section35has a thickness smaller than that of the side face of the housing1in the vertical direction, the step section is provided between the upper surface of the housing1above the thick section35and the upper surface of the thick section35. Therefore, when the frame4is joined to the upper surface of the side face of the housing1by using joining material such as brazing material, the brazing material is prevented from flowing on the upper surface of the thick section35, thereby preventing the frame4from being displaced toward the upper surface of the thick section35. As a result, the frame4is placed at a desired position on the upper surface of the housing1and joined thereto.

The screw fastening hole37may be a hole37which penetrates the thick section35in the vertical direction. For example, a screw may be inserted through the hole37from the upper opening of the thick section35and fixed on the external substrate. However, a screw is preferably inserted from the underside of the through hole of the external substrate into the opening of the hole37which is disposed on the lower surface of the thick section35and is fixed thereto. By fastening the screw to the thick section35, the thick section35can be securely fastened to the external substrate. Accordingly, the hole37is preferably open at least to the lower surface of the thick section35.

It is more preferable that the hole37is a threaded hole37having a thread groove on an internal peripheral surface. This facilitates fastening of a screw.

Accordingly, a screw is inserted into the through hole36from the upper side and is fixed on the external substrate while a screw is inserted into the hole37of the thick section35from the underside via the external substrate so that the screwing section31is fixed. As a result, fastening ability is improved.

When the thick section35is integrally formed with the side face of the housing1and the screwing section31as shown inFIGS. 1 to 5, fastening force is directly transmitted to the housing1when a screw is fastened to the hole37of the thick section35. Accordingly, correction effect of the housing1can be improved.

However, as shown inFIGS. 6 and 7, a screw fixing member131may be attached to the screwing section31. The screw fixing member131is fitted in a through hole H which is disposed between the thin section34of the screwing section31and the side face of the housing1and is joined by using joining material such as brazing material. The screw fixing member131is provided with the threaded hole37. A screw is fastened to the screw fixing member131from the lower surface of the external substrate so that the screwing section31is fastened to the external substrate. As a result, the housing1is fixed on the external substrate with the warpage being corrected, thereby improving heat dissipation from the housing1.

The screw fixing member131includes a clinch section131aformed of a lower edge that extends outward from the screw fixing member131so that the lower edge abuts against the lower surface of the screwing section31. Accordingly, the screw fixing member131can be prevented from being slipped off upward or displaced from the through hole H when joined to the screwing section31by using joining material such as brazing material. Further, the thread groove is threaded on the inner surface of the screw fixing member131so that a screw is attached from the lower side to the upper side. The screw fixing member131can be fixed on the external substrate S by inserting a screw from lower side to the upper side.

As shown inFIG. 7, the clinch section131aextends for example, 0.1 to 1 mm from a plane along the lower surface of the screwing section31. The clinch section131ahas a thickness of, for example, 0.5 to 3 mm in the vertical direction. Further, a groove is formed on the lower surface of the screwing section31so that the clinch section131ais fitted in the groove. The clinch section131ais embedded in the groove and is fitted thereto. Since the clinch section131ais partially embedded in the lower surface of the screwing section31, the screw fixing member131is prevented from being displaced in the plane direction and the vertical direction. The screw fixing member131is prevented from being displaced with respect to the screwing section31.

Further, as shown inFIG. 8, the clinch section131ais preferably sized such that a gap G is formed between the outer periphery of the clinch section131aand the inner periphery of the groove of the screwing section31.

The gap G can prevent interference of a force generated between the side face of the screw fixing member131and the inner surface of the groove of the screwing section31. Accordingly, a stress generated at a contact position between the through hole H and the side face of the screw fixing member131can be decreased. As a result, when the screw fixing member131is fixed on the screwing section31, the screw fixing member131and the screwing section31are prevented from being separated. Further, since the gap G is formed between the entire periphery of the lower section of the through hole H and the screw fixing member131, the screw fixing member131and the screwing section31are prevented from being separated.

Specifically, a metal material such as iron, copper, nickel, chrome, cobalt and tungsten may be used as a material of the screw fixing member131. Alternatively, an alloy or composite of those metal materials may be used. The screw fixing member131may be manufactured by a metal processing method such as cutting, forging and heading of an ingot or wire material of those metal materials.

Moreover, sub-screwing sections32are provided at two of four corners of the housing1where the screwing sections31are not provided. Unlike the screwing sections31, the sub-screwing sections32do not include a portion which corresponds to the thick section35. Specifically, the sub-screwing section32is a plate member having a through hole36through which a screw is inserted and has a length extending from the side face of the housing1which is smaller than the length of the screwing section31extending from the side face of the housing1.

<Configuration of Electronic Device100>

The electronic device100includes the package for housing electronic component10, the electronic component5mounted in the package10, and the cover6which is joined to the upper surface of the frame4to close the opening.

The electronic component5is mounted on the upper surface of the mounting substrate12. An element such as an optical semiconductor element, an IC (integrated circuit) element and a capacitor may be used as the electronic component5. The optical semiconductor element may include, for example, a light emitting element such as an LD (laser diode) element or a light receiving element such as a PD (photodiode) element.

The electronic component5is electrically connected to the wiring conductor of the input/output terminal2via a bonding wire. The electronic component5is electrically connected to an external wiring conductor via the bonding wire, the wiring conductor, the lead terminals24and the like.

The cover6is joined to the upper surface of the frame4. The cover6is joined to the upper surface of the frame4to close the opening of the recess1a. Accordingly, the electronic component5is hermetically sealed. By hermetically sealing the electronic component5, deterioration of the electronic component5due to long time usage of the electronic device100can be prevented.

A metal material such as iron, copper, nickel, chrome, cobalt and tungsten may be used as a material of the cover6. Alternatively, an alloy or composite of those metal materials may be used.

The frame4and the cover6are directly joined together. For example, the frame4is a metal frame having a shape that overlaps the cover6in a plan view and is also called as a so-called seal ring.

The electronic device100according to this embodiment has improved heat dissipation to the external substrate. Accordingly, when the electronic component5having high output is housed, the electronic component5can be protected and is allowed to function satisfactory.

Further, the present invention is not limited to the aforementioned embodiments, and various alterations and modifications are possible without departing from the spirit of the present invention.

For example, although the housing1has been described as being formed by the metal member11and the mounting substrate12in this embodiment, the invention is not limited thereto. Specifically, the housing1may be formed only by an insulation member. A ceramic material such as aluminum oxide based, mullite based, silicon carbide based, aluminum nitride based and silicon nitride based sintered material may be used as a material of the insulation member. Alternatively, the housing1may be formed only by a metal member.

Further, although the screwing sections31and the sub-screwing sections32are used as a configuration of screwing in this embodiment, the invention is not limited thereto. Specifically, the screwing sections31may be used at all the four corners. Alternatively, the screwing section31may be disposed at one of the four corners and the sub-screwing sections32may be disposed at the remaining three corners.

Further, although the screwing sections31and the sub-screwing sections32are provided at four positions in this embodiment, the invention is not limited thereto. Specifically, one, two, three or five or more positions may be also possible. In addition, the screwing sections31may not be necessarily provided at the corners, and the positions of the screwing sections31may be appropriately decided.

Further, although the housing1has a rectangular shape in a plan view in this embodiment, the invention is not limited thereto. Specifically, the housing1may have a polygonal shape or a circular shape.

Further, although the screwing section31and the housing1has been described as being integrally formed in this embodiment, the invention is not limited thereto. Specifically, the housing1and each of a plurality of screwing sections31may be individually formed and joined together.

REFERENCE SIGNS LIST

13(13a,13b,13c) notch section

10package for housing electronic component (package)