The present disclosure relates to an optical-device-mounting package, an electronic device, and an electronic module.
A TO (transistor outline)-can semiconductor laser including a laser chip is disclosed by Japanese Unexamined Patent Application Publication No. 2004-031900. TO-can packages exhibit poor heat dissipation. Therefore, TO-can packages employed for mounting high-power laser chips thereinside tend to be large so as to achieve satisfactory heat dissipation.
An optical-device-mounting package according to the present disclosure includes:
a base member having an upper surface and a slope, the slope being continuous with the upper surface and sloping downward in a direction away from the upper surface; and
an optical component having a first face and a second face, the second face being positioned opposite the first face,
wherein at least a part of the optical component is at a position higher than the upper surface, with at least a part of the second face being bonded to the slope with a bonding material, and
wherein the bonding material spreads from an area between the second face and the slope up to an area between the second face and the base member and higher than the upper surface.
An electronic device according to the present disclosure includes:
the above optical-device-mounting package; and
an optical device mounted in the optical-device-mounting package.
An electronic module according to the present disclosure includes:
the above electronic device; and
a module substrate on which the electronic device is mounted.
Embodiments of the present disclosure will now be described in detail with reference to the drawings.
An electronic device 10 according to the first embodiment includes an optical-device-mounting package 10A and an optical device 11. The optical device 11 is mounted in the optical-device-mounting package 10A. The optical-device-mounting package 10A includes a base member 2, an optical component 8, and a lid 9. The base member 2 has a first major surface Su, a second major surface Sb, and a recess 3. The second major surface Sb is positioned opposite the first major surface Su. The recess 3 provides an opening in the first major surface Su. The optical component 8 is mounted in the recess 3. The lid 9 covers the opening at the recess 3. The lid 9 is made of a material (glass or resin) that transmits light, and is bonded to the first major surface Su of the base member 2 with a bonding material.
The base member 2 chiefly includes a base upper member 2A and a base lower member 2B. The base upper member 2A is made of an insulating material. The base lower member 2B is made of metal. The base upper member 2A has a through-hole 3a (
A major part of the base upper member 2A is made of a ceramic material such as sintered aluminum oxide (alumina ceramic), sintered aluminum nitride, sintered mullite, or sintered glass-ceramic. The major part is obtained by, for example, punching or molding a ceramic green sheet, which is a ceramic material that is yet to be sintered, into a predetermined shape and sintering the sheet. The base upper member 2A further has electrodes D1 to D4 (
The base lower member 2B is made of a metal material having high thermal conductivity, such as copper or aluminum, and is formed by, for example, pressing. The depression 3b provided in the base lower member 2B has a first mounting portion 4, a second mounting portion 5, and a bank 6. The optical device 11 is mounted on the first mounting portion 4 with a sub mount 12 interposed therebetween. The optical component 8 is mounted on the second mounting portion 5. The bank 6 is positioned across the second mounting portion 5 from the first mounting portion 4. The base lower member 2B may be made of the same ceramic material as that for the base upper member 2A. If the base lower member 2B is made of a ceramic material, the base lower member 2B can be formed by molding or the like. If the base upper member 2A and the base lower member 2B are to be provided as sintered bodies of the same kind, the two may be formed together as an integral body.
The optical device 11 is, for example, a laser diode (semiconductor laser). The optical device 11 may be any light-emitting device that is directional. The optical device 11 is bonded to the upper surface of the sub mount 12 with a bonding material. The sub mount 12 is bonded to the upper surface of the first mounting portion 4 with a bonding material. The direction of light emission from the optical device 11 is a direction parallel to the upper surface of the first mounting portion 4 or the upper surface of the sub mount 12 (for example, a horizontal direction) and is heading toward the second mounting portion 5. The optical device 11 is electrically connected to the electrodes D3 and D4, which are provided in the recess 3 and on the base upper member 2A, with bonding wires E1 and E2 and with wire conductors running through the sub mount 12. The electrodes provided inside the recess 3 are connected to the electrodes D1 and D2, which are provided outside the recess 3, with wire conductors. If power is inputted to the optical device 11 through the electrodes D1 and D2, the optical device 11 is activated.
The optical component 8 is a flat mirror having a first face 8a and a second face 8b. The second face 8b is positioned opposite the first face 8a. The optical component 8 receives light from the optical device 11 and reflects the light upward. The first face 8a may have a reflective surface or a surface with reflective coating. The second face 8b may be regarded as a bonding surface. The light reflected as above travels upward through the lid 9 to the outside of the electronic device 10. The optical component 8 may include a flat base body and a reflective film provided over one face of the base body. The base body is made of, for example, glass; metal such as Al, Ag, or Si; or an organic material. If the base body is made of metal, the reflective film may be omitted. The reflective surface may be flat. The reflective film has a surface serving as the reflective surface. The reflective film may be a film of metal such as Ag, Al, Au, Pt, or Cr; or a film of a dielectric material such as TiO2, Ta2O5, or Nb2O5. The reflective film may be formed by a thin-film-forming technique such as deposition, sputtering, or plating.
The first mounting portion 4 has a flat upper surface spreading in, for example, the horizontal direction. The optical device 11 is bonded to the upper surface of the first mounting portion 4 with the sub mount 12 interposed therebetween. The flat surface referred to herein is a concept including a surface that is strictly flat, and a surface that is regarded as flat if small irregularities are ignored.
The second mounting portion 5 has a slope 5a. The slope 5a is angled with respect to the horizontal direction. The optical component 8 is bonded to the slope 5a with a bonding material 13. The slope 5a slopes downward from a bank top 6a toward the first mounting portion 4. The bank top 6a is an example of the upper surface according to the present disclosure.
The bank 6 is a raised portion positioned across the second mounting portion 5 from the first mounting portion 4 and is at a higher position than the first mounting portion 4. The bank top 6a is continuous with the slope 5a. The bank top 6a may be either a flat surface that is parallel to the upper surface of the second mounting portion 5 or a surface that is not parallel to the upper surface of the second mounting portion 5. The bank top 6a may be a part of the upper surface of the base lower member 2B and not overlapping the base upper member 2A.
<Structure for Mounting Optical Component>
The optical component 8 has the second face 8b positioned opposite the first face 8a. At least a part of the second face 8b is bonded to the slope 5a with the bonding material 13. The second face 8b may be flat. The bonding material 13 may be solder such as SnAgCu or AuSu; sintered metal nanoparticles chiefly composed of Au, Ag, or Cu; or an inorganic adhesive chiefly composed of alumina or zirconia.
The second face 8b of the optical component 8 has an upper end P2, which is at a position higher than the bank top 6a. The bonding material 13 spreads from an area between the second face 8b and the slope 5a up to an area between the second face 8b and the base member 2 and higher than the bank top 6a. The bonding material 13 may be present over an area W1, which spreads between the slope 5a and the second face 8b, and an area W2, which spreads along the second face 8b from a position higher than the bank top 6a down to the bank top 6a. The position higher than the bank top 6a refers to a position higher than a horizontal line H1, which is an extension of the bank top 6a, with the mounting surface for the optical device 11 being regarded as horizontal. If the bank top 6a is not horizontal, the horizontal line H1 refers to a line horizontally extended from a point of the bank top 6a that is closest to the slope 5a.
As illustrated in
As illustrated in
The edge (upper edge) of the bonding material 13 on the second face 8b is at a position closer to the first face 8a of the optical component 8 than a virtual vertical line (a line perpendicular to the mounting surface for the optical device 11) V2, which passes through the upper end P2 of the second face 8b. Specifically, in the vertical section illustrated in
As illustrated in
<Effects of Structure for Mounting Optical Component>
Here, the stresses acting in the horizontal directions A1 and A2 will be discussed by decomposing each of the stresses into a component acting in the thickness direction of the bonding material (a direction perpendicular to the slope 5a) and a component acting in the spreading direction of the bonding material 13. Since the directions of the respective components are angled with respect to the direction of the stress, neither of the two components of the stress becomes zero. That is, the bonding material 13 is subjected to a stress acting in the thickness direction as well. Such a stress acting in the thickness direction of the bonding material 13 is to be absorbed by a portion of the bonding material 13 that has a short length.
In the present embodiment, as illustrated in
In the present embodiment, as illustrated in
In the present embodiment, as illustrated in
In the present embodiment, as illustrated in
In the present embodiment, as illustrated in
To summarize, in the electronic device 10 according to the present embodiment, since the optical device 11 and the optical component 8 are mounted in a package including the base member 2 and the lid 9, the direction of light emission is changeable by the optical component 8, which increases the degree of freedom in the orientation of the optical device 11. That is, it is possible to orient the optical device 11 perpendicularly to the direction of light emission. Thus, the base member 2 having the recess 3 that is highly heat dissipative can be employed as a package. Hence, even if the optical device 11 that outputs high power is employed, the size of the electronic device 10 is kept small because of the highly heat-dissipative characteristic of the base member 2. In the present embodiment, with the above improvement in the structure for bonding the optical component 8, the optical component 8 is bonded with increased strength.
<Electronic Module>
An electronic module 100 according to an embodiment of the present disclosure is obtained by mounting the electronic device 10 on a module substrate 110. The module substrate 110 carrying the electronic device 10 may also carry other electronic devices, electronic elements, electric elements, and so forth. The module substrate 110 may be provided with electrode pads 111 and 112. The electronic device 10 may be bonded to the electrode pad 111 with a bonding material 113, such as solder. Furthermore, the electrodes D1 and D2 of the electronic device 10 may be connected to the electrode pad 112 on the module substrate 110 with bonding wires E11 and E12, through which signals may be outputted from the module substrate 110 to the electronic device 10.
The electronic module 100 according to the present embodiment includes the electronic device 10 that is highly heat dissipative and has increased strength in the bonding of the optical component. Therefore, the electronic module 100 provides high reliability.
While embodiments of the present disclosure have been described above, the optical-device-mounting package, the electronic device, and the electronic module according to the present disclosure are not limited to those described in the above embodiments. For example, while the above embodiments relate to a configuration in which the optical device is a laser diode, the optical device may be any of various other directional light-emitting devices such as a light-emitting diode. While the above embodiments relate to a configuration in which the optical component is a plate-shaped mirror, the optical component may be, for example, a mirror having a first face and a second face that are not parallel to each other, or a light-guiding member such as a prism. Other features, including the shape of the base member and the structure of packaging the optical device and the optical component, may be changed in any way.
The present disclosure is applicable to an optical-device-mounting package, an electronic device, and an electronic module.
Number | Date | Country | Kind |
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2019-178922 | Sep 2019 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2020/036790 | 9/29/2020 | WO |