JP2005217098A - Photo-semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an integrated and multi-function photo-semiconductor device by accommodating therein a larger number of components such as IC or the like which can transmit more effectively high-frequency signals and can also improve reliability in air-tightness of internal structure. <P>SOLUTION: The photo-semiconductor device comprises a base material 1 in which a convex 1b is formed to the entire part of the circumferential edge of the aperture of a through-hole 1a, a cover body 3 joined with the upper principal surface of the base material 1, a light transmitting member 4 joined with the cover body 3, a circuit board 5 joined with the upper surface of the convex 1b, and a photo-semiconductor element 2 mounted on the upper surface of the circuit board 5. The circuit board 5 includes a first electrode pad 6a and a second electrode pad 7a, and electrically connects the first electrode pad 6a and the second electrode pad 7a via internal wires 8a, 8b of the insulated circuit board. The second electrode pad 7a is joined with a pin 10 for external connection, and the base material 1 includes a portion in which the convex 1b is formed. Thickness of this concave is doubled or more than that of the remaining portion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical semiconductor device containing an optical semiconductor element used in fields such as optical communication.

  FIG. 9 shows an example of an optical semiconductor device in which optical semiconductor elements such as a semiconductor laser (LD) and a photodiode (PD) that operate at a high frequency in the field of conventional optical communication and the like are hermetically sealed. In the figure, 21 is a base, 22 is an optical semiconductor element, 23 is a metal lid, 24 is a translucent member, and 26 is an optical fiber.

The base 21 is made of a metal such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy or copper (Cu) -tungsten (W), and an optical semiconductor element 22 is provided at the center of the upper main surface. It is mounted and fixed on the upper main surface of the base 21 through a rectangular parallelepiped base 28 made of ceramics such as alumina (Al ₂ O ₃ ) ceramics. Further, the base 21 is formed with a through hole 21a penetrating between the upper and lower main surfaces for inserting an external connection pin 25 made of a metal such as Fe-Ni alloy or Fe-Ni-Co alloy. An external connection pin 25 serving as a terminal for conducting the inside and outside of the optical semiconductor device is inserted into the hole 21a, and a gap between the external connection pin 25 and the through hole 21a is filled with a bonding material made of a dielectric material such as glass, 21 and the external connection pin 25 are joined in an airtight manner. Thereby, the external connection pin 25 functions as a terminal for conducting inside and outside of the optical semiconductor device.

  The electrode of the optical semiconductor element 22 mounted on the base 28 is electrically connected to the tip of the external connection pin 25 on the optical semiconductor element 22 side via a bonding wire 29 or the like.

  Also, an Fe—Ni—Co alloy that is joined to the outer peripheral portion of the upper main surface of the base 21 and has a cylindrical shape with the upper end closed and the lower end 23c open, and a through hole 23b formed in the center of the upper end surface 23a. A lid 23 made of a metal such as is provided. The lower end 23c of the lid body 23 has, for example, a bowl shape as shown in FIG. 9, thereby increasing the bonding area between the base body 21 and the lid body 23, and the inside of the container constituted by the base body 21 and the lid body 23. Improves airtight reliability.

  Furthermore, the translucent member 24 is joined around the opening on the upper end surface 23a side of the through hole 23b so as to close the through hole 23b. The translucent member 24 has a disk shape, a lens shape, a spherical shape, a hemispherical shape, or the like made of glass, sapphire, or the like, and is airtightly bonded to the lid body 23 by bonding or soldering with glass.

  The optical semiconductor element 22 is accommodated in a container mainly composed of the base 21, the lid 23, and the translucent member 24, and hermetically sealed.

  Finally, a cylindrical metal fixing member 27 for fixing the optical fiber 26 is welded to the outer peripheral surface of the lid 23, and the optical fiber 26 is inserted and fixed from the outside into the through hole on the upper surface of the metal fixing member 27. An optical semiconductor device is formed by being fixed above the translucent member 24 and electrically connected to the external electrical circuit (not shown) at the outer end of the external connection pin 25 (for example, the following) Patent Document 1).

This optical semiconductor device excites light, such as laser light, into the optical semiconductor element 22 by an electrical signal supplied from an external electrical circuit, and transmits this light in the order of the translucent member 24 and the optical fiber 26. By transmitting to the outside through the optical device, it functions as an optical semiconductor device used for high-speed optical communication or the like. In this case, a monitoring PD (not shown) for confirming whether the optical signal is normally emitted from the optical semiconductor element 22 may be mounted. Alternatively, an optical signal transmitted from the outside via the optical fiber 26 is transmitted through the translucent member 24 and received by the optical semiconductor element 22, and the optical signal is converted into an electrical signal, thereby enabling high-speed optical communication or the like. It functions as an optical semiconductor device used in the above.
JP 2000-183369 A

  However, in the above conventional optical semiconductor device, since the external connection pin 25 is inserted through the through hole 21a of the base 21 and hermetically bonded through glass or the like, the diameter of the external connection pin 25 is the smallest in dimension. There are restrictions such as the processing limit, the hole size of the through hole 21a, and the minimum processing limit of the interval between the adjacent through holes 21a. Therefore, the position where the external connection pin 25 is inserted is limited, and the optical semiconductor element 22 and the external connection The bonding wire 29 for connecting to the connecting pin 25 tends to be long, and the impedance of the bonding wire 29 cannot be matched, so that the transmission loss of the high-frequency signal increases. As a result, there is a problem that it is difficult to efficiently transmit a high-frequency signal with the bonding wire 29.

  In addition, a large area is required to insert one external connection pin 25 into the base 21, and there is a problem that the number of external connection pins 25 attached to the base 21 is limited to a few.

  Further, only the optical semiconductor element 22 such as LD and PD and the monitor PD are accommodated in the optical semiconductor device, and the driver IC for driving the optical semiconductor element 22 and the preamplifier for amplifying the PD output signal are different semiconductor elements. It is necessary to electrically connect the driver IC or preamplifier and the optical semiconductor device via the external electric circuit, and the entire optical semiconductor device is enlarged to make the optical semiconductor element 22 function. There was also a problem.

  In addition, since the terminal structure is such that the external connection pin 25 is simply bonded to the base 21 through a bonding material such as glass, the external connection pin 25 is damaged by cracks or the like when stress is applied from the outside. As a result, airtightness inside the optical semiconductor device is impaired.

  Furthermore, it is difficult to use a signal line in which the portion of the external connection pin 25 that is not inserted into the through hole 21a is matched to the characteristic impedance, and the high-frequency signal transmitted through the external connection pin 25 is the external connection pin 25. In other words, transmission loss occurs due to reflection and the like, and high-frequency signals cannot be transmitted efficiently. In particular, there was a tendency that the transmission efficiency was remarkably deteriorated at a high frequency of 2 GHz or more.

  Therefore, the present invention has been completed in view of the above problems, and its purpose is to shorten the bonding wire for connecting the optical semiconductor element and the external connection pin to improve the high-frequency signal transmission characteristics. To increase the number of terminals attached to the optical semiconductor device and increase the number of components such as integrated circuit elements (ICs) accommodated therein, thereby integrating the optical semiconductor device and increasing its functionality. In addition, the internal airtight reliability can be improved and the high-frequency signal transmission efficiency can be improved by preventing reflection of the high-frequency signal by the external connection pin, so that the optical semiconductor element can be operated normally and stably over a long period of time. It is to make it highly reliable.

  The optical semiconductor device of the present invention is made of a plate-like metal in which a through-hole penetrating between the upper and lower main surfaces is formed and a convex portion is formed on the entire periphery of the opening of the through-hole on the upper main surface. A base having a cylindrical shape in which a through-hole is formed at the center of the upper end surface and the lower end is opened, and a metal lid having a lower end joined to the outer peripheral portion of the upper main surface of the base; A translucent member bonded around the opening of the through hole of the lid, a wiring board that covers the through hole and is bonded to the upper surface of the convex part, and light placed on the upper surface of the wiring board A plurality of first electrode pads formed on the upper surface of the insulating substrate formed by laminating a plurality of insulating layers, and a plurality of wiring electrodes disposed on the lower surface of the insulating substrate. A second electrode pad, and the first electrode pad and a corresponding one before A second electrode pad is electrically connected via an internal wiring of the insulating substrate, an external connection pin is joined to each of the plurality of second electrode pads, and the base is formed of the convex portion The thickness of the portion where the is formed is twice or more the thickness of the remaining portion.

  The optical semiconductor device of the present invention is preferably characterized in that 1 ≦ A / B ≦ 10, where A is the thickness of the wiring board and B is the thickness of the substrate.

  The optical semiconductor device of the present invention is made of a plate-like metal in which a through-hole penetrating between the upper and lower main surfaces is formed and a convex portion is formed on the entire periphery of the opening of the through-hole on the upper main surface. A base, a cylindrical lid having a through hole formed in the central portion of the upper end surface and having a lower end opened, and a lower end joined to the outer peripheral portion of the upper main surface of the base; and a lid A translucent member joined around the opening of the through hole, a wiring board covering the through hole and joined to the upper surface of the convex part, and an optical semiconductor element placed on the upper surface of the wiring board. The wiring board includes a plurality of first electrode pads formed on the upper surface of the insulating substrate formed by laminating a plurality of insulating layers and a plurality of second electrode pads disposed on the lower surface of the insulating substrate. A first electrode pad and a second electrode pad corresponding to the first electrode pad inside the insulating substrate. The external connection pins are joined to each of the plurality of second electrode pads, and the base has a thickness of the remaining portion of 2 where the convex portions are formed. By being more than twice, a large number of electrode pads, inner layer conductor layers and through conductors can be formed at fine intervals on the upper and lower surfaces and inside of the wiring board. As a result, not only optical semiconductor elements and monitor PDs, Signal input / output such as a driver IC for driving an optical semiconductor element and a preamplifier for amplifying a PD output signal can be performed by this wiring board, and a driver IC, a preamplifier, and the like can be mounted in the optical semiconductor device. Accordingly, since a driver IC or the like that needs to be electrically connected to the optical semiconductor device via an external electric circuit can be mounted and integrated in the optical semiconductor device, the entire device for driving the optical semiconductor element Can be miniaturized.

  In addition, since the first electrode pad on the upper surface of the wiring board can be formed in the vicinity of the optical semiconductor element, the first electrode pad and the optical semiconductor element can be electrically connected by a very short bonding wire. The transmission loss of the high frequency signal can be minimized.

  In addition, since a wiring board in which terminals (external connection pins) conducting inside and outside of the optical semiconductor device are joined with a brazing material or the like is used, when external stress is applied to the external connection pins, In comparison, it is possible to effectively prevent the occurrence of breakage such as cracks in the joint portion of the terminal and break the airtightness inside the optical semiconductor device. Therefore, the airtight reliability is greatly improved as compared with the conventional terminal structure in which the external connection pin is joined to the through hole of the base body through a joining material such as glass.

  Furthermore, it has a plurality of second electrode pads arranged in two rows on the lower surface of the insulating substrate, and an external connection pin is joined to each of the plurality of second electrode pads, so that the external connection The external electric circuit board can be sandwiched between the rows of pins. For example, the external connection pin and the wiring conductor of the external electric circuit board can be connected with their positions being matched. As a result, the operation of mounting the optical semiconductor device on the external electric circuit board becomes extremely easy, and the connection between the external connection pin and the wiring conductor of the external electric circuit board is performed at a portion close to the wiring board of the external connection pin. Therefore, it is possible to minimize the length of transmission of the high-frequency signal through the external connection pin, and to minimize the occurrence of transmission loss such as reflection at the external connection pin.

  Further, since the thickness of the portion where the convex portion is formed on the base is more than twice the thickness of the remaining portion, the boundary between the portion where the convex portion of the base is formed and the remaining portion is easily deformed, and the lid Even if thermal stress occurs when joining the lower end of the base and the outer peripheral portion of the upper main surface of the base body by a welding method such as resistance welding, the boundary between the portion where the convex portion of the base body is formed and the remaining portion is defined. By appropriately deforming, the stress can be effectively relieved, and strain is hardly transmitted to the joint portion of the base body with the wiring board.

  Further, by forming the convex portion, the distance from the joint between the lid and the base to the joint between the wiring board and the base can be increased, and the base and the lid are welded together by a resistance welding method or the like. Therefore, it is possible to suppress the heat at the time of bonding from being transmitted to the bonding portion between the wiring board and the base body. As a result, the stress generated at the junction between the wiring board and the substrate can be reduced.

  In the optical semiconductor device of the present invention, it is preferable that when the thickness of the wiring board is A and the thickness of the base body is B, 1 ≦ A / B ≦ 10. Even if the base is bonded, it is possible to effectively suppress the occurrence of breakage such as cracks in the wiring board due to the difference in thermal expansion between the wiring board and the base. Further, it is possible to effectively suppress the occurrence of breakage such as cracks in the wiring board due to the stress generated when the lid is joined to the base. As a result, the optical semiconductor element can be made highly reliable so that it can operate normally and stably over a long period of time without impairing the airtightness inside the optical semiconductor device.

  The optical semiconductor device of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an embodiment of an optical semiconductor device according to the present invention. 1 is a substrate, 2 is an optical semiconductor element, 4 is a translucent member, 5 is a wiring board, 12 is an optical fiber, 3 Is a metal lid. The base 1 and the wiring substrate 5 basically constitute an optical semiconductor device.

  The optical semiconductor device of the present invention is a flat metal in which a through hole 1a penetrating between upper and lower main surfaces is formed, and a convex portion 1b is formed on the entire periphery of the peripheral portion of the opening of the through hole 1a on the upper main surface. A base 1 made of metal, a cylindrical shape in which a through hole 3b is formed in the center of the upper end surface and the lower end 3c is opened, and a lower end 3c is joined to the outer peripheral portion of the upper main surface of the base 1 A lid 3, a translucent member 4 joined around the opening of the through hole 3b of the lid 3, a wiring board 5 covering the through hole 1a and joined to the upper surface of the convex portion 1b, and a wiring board The wiring substrate 5 includes a plurality of first electrode pads 6a formed on a top surface of an insulating substrate formed by laminating a plurality of insulating layers. And a plurality of second electrode pads 7a disposed on the lower surface of the insulating substrate. The pad 6a and the corresponding second electrode pad 7a are electrically connected via the internal wirings 8a and 8b of the insulating substrate, and the external connection pin 10 is joined to each of the plurality of second electrode pads 7a. In the substrate 1, the thickness of the portion where the convex portion 1b is formed is twice or more the thickness of the remaining portion.

  The substrate 1 of the present invention has a flat plate shape such as a disk shape or a rectangular shape, and is made of a metal such as an Fe—Ni—Co alloy, an Fe—Ni alloy, or a Cu—W alloy, and the ingot is rolled or punched. It is manufactured in a predetermined shape by applying a conventionally well-known metal processing method. The base body 1 is provided with a through hole 1a that penetrates between the upper and lower main surfaces of the base body 1 in order to insert the external connection pin 10 therethrough. In this through hole 1a, the wiring board 5 is covered with a brazing material such as silver (Ag) brazing so as to cover the through hole 1a through the second coplanar conductor layer 7b provided on the outer peripheral portion of the lower surface thereof. Airtightly joined. Here, the base body 1 is formed with a convex portion 1b around the entire periphery of the opening of the through hole 1a, and the wiring board 5 is bonded onto the convex portion 1b. And the thickness of the site | part in which the convex part 1b of the base | substrate 1 was formed is 2 times or more of the thickness of a remainder.

  With this configuration, the boundary between the portion where the convex portion 1b of the base 1 is formed and the remaining portion is easily deformed, and the lower end 3c of the lid 3 and the outer peripheral portion of the upper main surface of the base 1 are welded by resistance welding or the like. Even when thermal stress is generated when joining by the method, the stress can be effectively relieved by appropriately deforming the boundary between the portion where the convex portion 1b of the base body 1 is formed and the remaining portion. The strain is difficult to be transmitted to the joint portion with the one wiring board 5.

  Further, by forming the convex portion 1b, the distance from the junction between the lid 3 and the base 1 to the junction between the wiring board 5 and the base 1 can be increased, and the base 1 and the lid 3 can be connected to each other. The heat at the time of joining by a welding method such as resistance welding can be prevented from being transmitted to the joint portion between the wiring board 5 and the base 1. As a result, the stress generated at the joint between the wiring substrate 5 and the base body 1 can be reduced.

  When the thickness of the portion of the base 1 where the convex portion 1b is formed is less than twice the thickness of the remaining portion, when the base 1 and the lid 3 are joined by a welding method such as a resistance welding method, The remaining portion is not easily deformed, and the strain applied to the base body 1 when the base body 1 and the lid 3 are welded is not sufficiently absorbed by the remaining portion, and is easily transmitted to the joint portion of the base body 1 with the wiring board 5. As a result, stress is applied to the wiring board 5 and breakage such as cracks is likely to occur, making it difficult to keep the inside of the container airtight.

The wiring board 5 is produced as follows. For example, in the case of Al ₂ O ₃ ceramics, first, an appropriate organic binder, plasticizer, solvent, etc. are added to the raw material powders such as aluminum oxide, silicon oxide (SiO ₂ ), magnesium oxide (MgO) and calcium oxide (CaO). Add and mix to form a slurry. A plurality of ceramic green sheets are obtained from this by a tape forming technique such as a doctor blade method or a calender roll method. Next, a metal paste obtained by adding an appropriate organic binder, plasticizer, solvent, etc. to a high melting point metal powder such as W or molybdenum (Mo) to the ceramic green sheet is mixed with a thick film such as a screen printing method. The metallized layer which becomes the inner layer conductor layer 8b which is the first electrode pad 6a, the second electrode pad 7a, the second coplanar conductor layer 7b, and a part of the internal wiring is formed into a predetermined pattern by printing and coating by a forming technique. Form. Further, by punching with a mold or the like, a through hole to be a through conductor 8a which is a part of the internal wiring is formed at a desired position of each ceramic green sheet, and a high melting point such as W or Mo is formed in the through hole. A metal paste obtained by adding and mixing an appropriate organic binder, plasticizer, solvent, etc. to the metal powder is filled. Thereafter, a plurality of ceramic green sheets are laminated and fired at a temperature of about 1600 ° C. in a reducing atmosphere.

  Further, when the thickness of the wiring board 5 is A and the thickness of the substrate 1 is B, it is preferable that 1 ≦ A / B ≦ 10. Thereby, even if the metal substrate 1 is bonded to the wiring substrate 5 made of an insulating substrate, it is possible to effectively suppress the occurrence of breakage such as cracks in the wiring substrate 5 due to the difference in thermal expansion between the wiring substrate 5 and the substrate 1. be able to. As a result, the optical semiconductor element 2 can be operated normally and stably for a long time without impairing the airtightness inside the optical semiconductor device.

  In the case of A / B <1, the wiring board 5 becomes too thin with respect to the base body 1 to weaken the strength, and the wiring board 5 is likely to be damaged due to a difference in thermal expansion from the base body 1. When A / B> 10, the wiring board 5 becomes thick, and the lid 3 is secured to secure a volume inside the container composed of the base body 1, the lid body 3, the translucent member 4, and the wiring board 5. As a result, the size of the semiconductor device is increased, and it is not suitable for the recent demand for downsizing of the optical semiconductor device. Further, when the wiring board 5 becomes thicker, the through conductor 8a functioning as a line from the external connection pin 10 to the optical semiconductor element 2 becomes longer, and reflection loss and transmission loss generated in the high-frequency signal transmitted through the through conductor 8a. It becomes large and the operativity of the optical semiconductor element 2 tends to deteriorate.

  Furthermore, it is preferable that the width of the joint portion between the base body 1 and the wiring substrate 5 is 0.3 mm or more. As a result, the bonding strength between the base 1 and the wiring board 5 can be increased, and the inside of the container composed of the base 1, the lid 3, the translucent member 4, and the wiring board 5 can be kept airtight.

  For example, as shown in FIG. 2, a plurality of second electrode pads 7a are arranged in two rows on the lower surface of the wiring board 5, and external connection pins 10 are provided on the respective second electrode pads 7a. Are connected by a brazing material such as Ag brazing. Preferably, as shown in FIG. 3, the external connection pin 10 is provided with a flange 10a at the joint (upper end) with the second electrode pad 7a, and the external connection pin 10 is connected to the electrode pad. 7a can be firmly joined.

  In this way, the external connection pins 10 can be arranged in two rows on the lower surface of the wiring board 5 so that the external electric circuit board can be sandwiched between the rows of the external connection pins 10. And the position of the wiring conductor of the external electric circuit board can be matched. As a result, the optical semiconductor device can be easily mounted on the external electric circuit board, and the connection between the external connection pin 10 and the wiring conductor of the external electric circuit board is close to the wiring board 5 of the external connection pin 10. The length of transmission of the high-frequency signal through the external connection pin 10 can be minimized, and transmission loss such as reflection at the external connection pin 10 can be minimized.

  Preferably, as shown in FIG. 4, a first coplanar conductor layer 6b is formed on the entire upper surface of the wiring board 5 around the first electrode pad 6a at a constant interval, and the second electrode pad 7a The second coplanar conductor layer 7b is preferably formed on the entire lower surface of the wiring board 5 with a constant interval around the periphery. With this configuration, a shielding effect (electromagnetic shielding effect) is obtained on the upper and lower surfaces of the wiring board 5, and when a high-frequency signal inputs and outputs the wiring board 5 through the first electrode pad 6 a and the second electrode pad 7 a, The high frequency signal is prevented from being normally input / output due to the influence of noise or the like, and loss due to the radiation of the high frequency signal on the upper and lower surfaces of the wiring board 5 is prevented.

  More preferably, as shown in FIG. 5, the second electrode pad 7a is provided at a position facing the first electrode pad 6a, and the first electrode pad 6a and the second electrode pad 7a are electrically connected. It is preferable to provide a plurality of grounding through conductors 9a at regular intervals around the circumference of the through conductor 8a. In this case, as shown in the cross-sectional view along line AA ′ of FIG. 5 in FIG. 6A, a circular shape centering on the center C1 of the through conductor 8a is provided between the ceramic green sheets and around the through conductor 8a. The inner conductor layer 8b is provided, and a plurality of ground through conductors 9a are provided at regular intervals so that the center C2 of the ground through conductor 9a is placed on the circumference of the diameter D centered on the center C1. A circular inner ground conductor layer 9b centering on the center C2 is provided around the ground through conductor 9a.

  The inner layer conductor layer 8b and the inner layer ground conductor layer 9b are for reliably connecting the through conductor 8a and the ground through conductor 9a in the upper and lower ceramic green sheets, respectively.

  With the above configuration, a high-frequency signal transmitted through the through conductor 8a can be transmitted in the coaxial line mode, and transmission loss such as reflection can be suppressed and transmitted without waste. Further, as shown in FIG. 6B, the inner ground conductor layer 9b may be provided around the inner conductor layer 8b around the inner conductor layer 8b at regular intervals and outside the circumference around the through conductor 8a. The high-frequency signal transmitted through 8a can be more approximated to the mode of the coaxial line, and transmission loss can be further suppressed.

  The optical semiconductor device is preferably hermetically sealed in order to prevent malfunction of the optical semiconductor element 2 and the like. If the inside is hermetically sealed, a pressure due to a pressure difference between the inside and outside is applied to the outer surface of the lid 3 and the lid 3 may be deformed. Therefore, in order to distribute the pressure applied to the outer surface of the optical semiconductor device substantially uniformly due to the pressure difference and prevent pressure concentration, the lid 3 is preferably cylindrical in cross-sectional shape (transverse cross-sectional shape).

  The base 1 and the wiring board 5 can be aligned with each other. As shown in the plan view of the base 1 and the wiring board 5 in FIG. It is preferable to provide a straight portion 1b and a straight portion 5b respectively. By having such a straight line portion 5b, the wiring board 5 is formed by punching the hatched portion with the ceramic green sheet 5a, multilayering and firing, and then slicing the dotted portion as shown in FIG. it can. When the wiring board 5 is circular, it is difficult to cut the fired body into a circular shape, so that the ceramic green sheet 5a is punched into circular pieces and fired. In this case, since each circular piece must be installed in the firing furnace, the working efficiency during firing is reduced. On the other hand, when the wiring board 5 has the straight portion 5b, it can be fired in the state of a mother board having a large number of wiring board 5 regions, and the working efficiency is remarkably improved.

  Moreover, when providing the linear part 1b in the base | substrate 1, it is good to form two linear parts in the lower end 3c for attaching the cover body 3 to the base | substrate 1 as mentioned above. In this case, the outer peripheries of the base body 1 and the lower end 3c are made to coincide with each other, and the lid body 3 is joined to the upper main surface of the base body 1 without being displaced so that the inside can be surely kept airtight and can be joined easily. There is.

  The lid 3 is manufactured in a predetermined shape by subjecting a metal ingot such as an Fe—Ni—Co alloy to a conventionally known metal processing method such as rolling, punching, or drawing. The lid 3 may be formed by individually manufacturing a cylindrical portion and an upper end surface 3a and joining them by brazing, soldering, welding, or the like.

  The translucent member 4 is airtightly bonded to the lid 3 by glass bonding or soldering around the upper end surface 3a side opening of the through hole 3b so as to close the through hole 3b. The translucent member 4 has a disk shape, a lens shape, a spherical shape, a hemispherical shape, or the like made of glass, sapphire, or the like. In the case of a hemispherical part, it is joined to the lid 3 at the outer peripheral part of the flat part.

  The optical fiber 12 is held by being bonded to a cylindrical holding part made of zirconia or the like, and the holding part is placed on a substantially cylindrical metal fixing member 13 made of a metal such as SUS. The lower end surface of the metal fixing member 13 is joined to the outer peripheral surface of the lid 3 by welding such as a laser welding method. The optical fiber 12 is fixed above the translucent member 4 through the metal fixing member 13, so that an optical semiconductor device as a product is obtained. As a result, it is possible to exchange optical signals between the optical semiconductor element 2 housed inside and the outside via the optical fiber 12.

  In the present invention, the translucent member 4 is preferably joined around the opening on the upper end surface 3a side of the through-hole 3b. In this case, the following points are advantageous. That is, heat when the metal fixing member 13 is welded to the outer periphery of the lid 3 is locally applied to the lid 3, and tensile stress due to thermal expansion is applied to the joint surface of the lid 3 with the translucent member 4. If applied, the translucent member 4 is easily peeled off from the lid 3. However, since the optical semiconductor device is airtight from the outside to make the inside airtight, the translucent member 4 is pressed against the lid 3 by the atmospheric pressure. It becomes difficult to peel off. On the other hand, when the translucent member 4 is joined to the periphery of the opening on the back surface side of the upper end surface 3a of the through hole 3b, a tensile stress that causes the translucent member 4 to be peeled off by a stress due to thermal expansion and a pressure due to atmospheric pressure. However, the translucent member 4 is easily detached from the lid 3.

  The optical semiconductor device of the present invention is an optical semiconductor device as a product by electrically connecting the electrodes of the optical semiconductor element 2 to an external electric circuit. In this optical semiconductor device, for example, an optical signal supplied from an external electric circuit excites the optical semiconductor element 2 with light such as laser light, and transmits this light in the order of the translucent member 4 and the optical fiber 12, and the optical fiber. By transmitting to the outside via 12, it functions as an optical semiconductor device used for high-speed optical communication or the like.

  Examples of the optical semiconductor device of the present invention will be described below.

  The optical semiconductor device of FIG. 1 was manufactured as follows. First, a circular through hole 1a having a disk shape of 7.7 mm in diameter and having a diameter of 4.2 mm is provided at the center, and a convex portion 1b having a width of 0.8 mm is formed around the through hole 1a on the upper surface. The substrate 1 made of the Fe-Ni-Co alloy thus prepared was facilitated.

Then, a wiring board 5 made of an Al ₂ O ₃ sintered body and having a disk shape with an outer diameter of 5 mm was joined to the upper surface of the convex portion 1a of the base 1 via an Ag brazing material.

  Next, on the outer periphery of the upper surface of the base body 1, the inner diameter of the cylindrical portion is 5.7 mm, the outer diameter of the lower end 3c is 7.7 mm, the height from the lower end 3c to the upper end surface 3a is 3 mm, and the thickness is 0.3 mm. A translucent member 4 made of disc-shaped sapphire having a diameter of 3.2 mm and a thickness of 0.3 mm was brazed via Ag brazing around a circular through hole 3b having a diameter of 2.4 mm provided on the upper end surface 3a. The lid 3 made of Fe—Ni—Co alloy was joined by a seam welding method.

  Here, the thickness B of the portion of the substrate 1 where the convex portions 1a are formed is 0.4 mm or 0.6 mm, the thickness A of the wiring board 5 is 0.5 mm, and the thickness of the remaining portion of the substrate 1 is shown in Table 1 or Table 1. Twenty samples of each optical semiconductor device were produced so as to obtain various values shown in FIG.

The airtightness of each sample was evaluated according to the following procedure. First, each sample was immersed in a highly volatile liquid of a fluorinate system, and a gross leak test was conducted to evaluate the presence or absence of bubbles in the liquid. The sample was defective. Further, for a sample that was a non-defective product in the gross leak test, He was pressurized at 4900 Pa (Pascal) for 2 hours and then He leak test, that is, He was pressed into the inside of the optical semiconductor device. A test for detecting He leaking to the outside is conducted, and a sample having a He detection amount of 5.0 × 10 ⁻⁹ Pa · m ³ / sec or less is regarded as a non-defective product, and the detection amount is 5.0 × 10 ⁻⁹ Pa · m ³ A sample exceeding / sec was regarded as a defective product. The evaluation results are shown in Tables 1 and 2.

  From Tables 1 and 2, when the thickness of the portion of the substrate 1 where the convex portion 1b is formed is less than twice the thickness of the remaining portion, poor airtightness occurred.

  From the above, it has been found that when the thickness of the portion of the substrate 1 where the convex portion 1b is formed is twice or more the thickness of the remaining portion, the inside of the optical semiconductor device can be kept airtight.

  The optical semiconductor device of FIG. 1 was manufactured as follows. First, a circular through hole 1a having a disk shape of 7.7 mm in diameter and having a diameter of 4.2 mm is provided at the center, and a convex portion 1b having a width of 0.8 mm is formed around the through hole 1a on the upper surface. The substrate 1 made of the Fe-Ni-Co alloy thus prepared was facilitated.

Then, a wiring board 5 made of an Al ₂ O ₃ sintered body and having a disk shape with an outer diameter of 5 mm was joined to the upper surface of the convex portion 1a of the base 1 via an Ag brazing material.

  Next, on the outer periphery of the upper surface of the base body 1, the inner diameter of the cylindrical portion is 5.7 mm, the outer diameter of the lower end 3c is 7.7 mm, the height from the lower end 3c to the upper end surface 3a is 3 mm, and the thickness is 0.3 mm. A translucent member 4 made of disc-shaped sapphire having a diameter of 3.2 mm and a thickness of 0.3 mm was brazed via Ag brazing around a circular through hole 3b having a diameter of 2.4 mm provided on the upper end surface 3a. The lid 3 made of Fe—Ni—Co alloy was joined by a seam welding method.

  Here, the thickness B of the portion of the base 1 where the convex portion 1a is formed is 0.4 mm or 0.6 mm, and the thickness A of the remaining portion of the base 1 is the thickness B of the portion of the base 1 where the convex portion 1a is formed. 20 samples each of the optical semiconductor device were manufactured so that the thickness of the wiring substrate 5 would be various values shown in Table 3.

The airtightness of each sample was evaluated according to the following procedure. First, each sample was immersed in a highly volatile liquid of a fluorinate system, and a gross leak test was performed to evaluate the presence or absence of bubbles in the liquid. The sample was defective. Furthermore, for a sample that was a non-defective product in the gross leak test, He was pressurized at 4900 Pa (Pascal) for 2 hours, and then He leak test, that is, He was pressed into the inside of the optical semiconductor device. A test for detecting He leaking to the outside is conducted, and a sample having a He detection amount of 5.0 × 10 ⁻⁹ Pa · m ³ / sec or less is regarded as a non-defective product, and the detection amount is 5.0 × 10 ⁻⁹ Pa · m ³ A sample exceeding / sec was regarded as a defective product. The evaluation results are shown in Table 3.

  From Table 3, when the thickness A of the wiring board 5 is less than 1 times the thickness of the base body 1, an airtight defect occurred.

  From the above, it has been found that when the thickness of the wiring substrate 5 is one or more times the thickness B of the portion where the convex portion 1a of the base body 1 is formed, the airtightness inside the optical semiconductor device can be satisfactorily maintained. However, if the thickness A of the wiring substrate 5 is larger than 10 times the thickness B of the portion of the base body 1 where the protrusions 1a are formed, the optical semiconductor device becomes large and unsuitable for practical use.

  In addition, this invention is not limited to the said embodiment and Example, A various change may be performed in the range which does not deviate from the summary of this invention.

It is sectional drawing which shows the example of embodiment about the optical semiconductor device of this invention. It is an enlarged plan view of the 2nd electrode pad of the wiring board in the optical semiconductor device of the present invention. It is an expanded sectional view which shows the other example of embodiment of the pin for external connection in the optical semiconductor device of this invention. (A) is an enlarged plan view showing another example of the embodiment of the first electrode pad of the wiring board in the optical semiconductor device of the present invention, and (b) is the second wiring board in the optical semiconductor device of the present invention. It is an enlarged plan view which shows the other example of embodiment of an electrode pad. It is an expanded sectional view which shows the other example of embodiment of the wiring board in the optical semiconductor device of this invention. (A), (b) is the expanded sectional view in the A-A 'surface of FIG. 5, which shows the other example of embodiment of the wiring board in the optical semiconductor device of this invention, respectively. It is a top view which shows the other example of embodiment about the base | substrate and wiring board in the optical semiconductor device of this invention. It is a top view which shows the other example of embodiment about the wiring board in the optical semiconductor device of this invention. It is sectional drawing of the conventional optical semiconductor device.

Explanation of symbols

1: Base 1a: Through hole 1b: Protruding part 2: Optical semiconductor element 3: Cover 3a: Upper end surface 3b: Through hole 4: Translucent member 5: Wiring substrate 6a: First electrode pad 7a: Second Electrode pads 8a and 8b: internal wiring
10: Pin for external connection

Claims (2)

A flat plate-like metal base body having a through hole penetrating between the upper and lower main surfaces and having a convex portion formed on the entire periphery of the opening of the through hole on the upper main surface, and a center portion of the upper end surface A metal lid having a lower end joined to the outer peripheral portion of the upper main surface of the base body, and an opening of the through hole of the lid A translucent member bonded to the periphery of the substrate, a wiring substrate that covers the through hole and is bonded to the upper surface of the convex portion, and an optical semiconductor element mounted on the upper surface of the wiring substrate. The wiring board includes a plurality of first electrode pads formed on an upper surface of an insulating substrate formed by laminating a plurality of insulating layers, and a plurality of second electrode pads disposed on the lower surface of the insulating substrate. And the first electrode pad and the second electrode pad corresponding to the first electrode pad It is electrically connected via an internal wiring of an insulating substrate, and an external connection pin is bonded to each of the plurality of second electrode pads, and the base has a thickness at a portion where the convex portion is formed. Is at least twice the thickness of the remaining portion. 2. The light according to claim 1, wherein 1 ≦ A / B ≦ 10, wherein A is a thickness of the wiring board and B is a thickness of a portion of the base on which the convex portion is formed. Semiconductor device.

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