JP2004165507A - Package for storing semiconductor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To overcome a problem that impedance decreases at a junction between a wiring conductor on a circuit board and a central conductor of a coaxial connector to enlarge reflection loss of high frequency signals and spoil operating properties of a semiconductor element. <P>SOLUTION: A nonforming part of an internal-layer ground conductor 2' in the circuit board is formed below the region where the central conductor 7c of the coaxial connector 7 is connected to the wiring conductor 2a having a coplanar line structure fitted with ground on the circuit board, and the length of the central conductor 7c projecting inside the frame body 6 from an insulator 7b is under a quarter of the wavelength of a high frequency signal. It is preferred to increase the interval between the wiring conductor 2a and a coplanar ground conductor 2b above the nonforming part. The fluctuation in impedance at the junction between the wiring conductor 2a and the central conductor 7c can be suppressed effectively. Moreover, since resonance is not generated in the central conductor 7c projecting from the insulator 7b, the reflection loss of high frequency signals can be extremely reduced, resulting in making the operating properties of the semiconductor element such as an optical semiconductor element 8 satisfactory. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention accommodates various semiconductor elements operating at a high frequency used in optical communication, microwave communication, millimeter wave communication, and the like, together with a circuit board electrically connected to the semiconductor element. The present invention relates to a semiconductor device housing package having a coaxial connector to be connected.
[0002]
[Prior art]
One of the semiconductor element storage packages used for optical communication, microwave communication, millimeter wave communication, etc., which stores various semiconductor elements operating at a high frequency together with a circuit board electrically connected to the semiconductor elements. FIG. 3 is a cross-sectional view showing an example of a conventional semiconductor element storage package used in the communication field.
[0003]
As shown in FIG. 1, a conventional semiconductor element storage package 101 has a semiconductor element 108 such as an LD (laser diode) or PD (photodiode) mounted on a top surface via a mounting base 103. It has the base 104 provided with the mounting portion 109.
[0004]
The base 104 is made of a metal material such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy or a copper (Cu) -tungsten (W) alloy.
[0005]
A frame body 106 is attached to the upper surface of the base 104 via a brazing material such as a silver brazing material so as to surround the mounting portion 109. On one side of the frame body 106, a through hole 106b used as an optical transmission path for optically coupling with the semiconductor element 108 is formed. The frame 106 is made of a metal material such as an Fe-Ni-Co alloy.
[0006]
The periphery of the through hole 106b on the outer surface of the frame body 106 is made of a metal material such as an Fe-Ni-Co alloy or an Fe-Ni alloy that approximates the thermal expansion coefficient of the frame body 106, and is used to prevent return light. A cylindrical fixing member 114 to which a metal holder 112 to which an optical isolator 111 and an optical fiber 113 are bonded with a resin adhesive is fixed is joined with a brazing material such as a silver brazing material. A translucent member 110, which is made of amorphous glass or the like and functions as a condenser lens and has a function of cooling the inside of the semiconductor element housing package 101, is fixed to the cylindrical fixing member 114. Note that the fixing member 114 and the metal holder 112 have their respective end faces fixed by YAG laser welding or the like.
[0007]
On the other hand, the fixing member 114 and the translucent member 110 are formed by combining the plating layer formed on the inner peripheral surface of the fixing member 114 and the plating layer formed on a part of the outer peripheral surface of the translucent member 110 with Au-. It is fixed by brazing with a low melting point brazing material such as Sn alloy solder.
[0008]
The coaxial connector 107 is made of a metal material such as an Fe-Ni-Co alloy, and is formed of a low melting point brazing material such as an Au-Sn alloy solder on the inner peripheral surface of the through hole 106a formed on the side of the frame 106. A cylindrical holder 107a as an outer conductor to be brazed, a glass 107b as an insulator made of a dielectric material such as borosilicate glass filled in the holder 107a, and a central axis portion of the glass 107b. And a central conductor 107c that is mounted and conducts the inside and outside of the semiconductor element housing package 101. The coaxial connector 107 has a function of electrically connecting an external electric circuit and the semiconductor element 108 via the wiring conductor 102 a of the circuit board 102 and the bonding wire 115, and a function of closing the inside of the semiconductor element housing package 101. Having.
[0009]
In the coaxial connector 107, impedance matching at the time of transmitting a high-frequency signal is performed between the center conductor 107c through which a high-frequency signal is transmitted and the outer peripheral portion thereof, ie, the outer peripheral conductor 107a made of a metal material and the inner peripheral surface of the through hole 106a. It constitutes a possible coaxial structure.
[0010]
The electrical connection between the coaxial connector 107 and the semiconductor element 108 is made by a wiring conductor 102a (a coplanar line formed on the circuit board 102 so that the impedance inside the through hole 106a of the central conductor 107c is the same as the impedance). The same plane ground conductor is not shown) and the tip of the center conductor 107c of the coaxial connector 107 are joined via a low melting point brazing material such as tin-lead solder, and the wiring conductor 102a and the semiconductor element 108 are bonded. This is performed by connecting with a wire 115.
[0011]
In such a semiconductor element storage package 101, the mounting base 103 on which the semiconductor element 108 and the circuit board 102 are mounted is mounted and fixed on the mounting section 109 via an adhesive such as a resin adhesive or a brazing material. After that, one end of the center conductor 107c is joined to the wiring conductor 102a on the upper surface of the circuit board 102 with a low melting point brazing material. Next, the semiconductor element 108 and the wiring conductor 102a are electrically connected by the bonding wire 115. After that, the metal holder 112 to which the optical isolator 111 and the optical fiber 113 are fixed is welded to the fixing member 114. Then, the lid 105 is joined to the upper surface of the frame 106 by seam welding, brazing, or the like, whereby an optical semiconductor device as a product is obtained.
[0012]
Further, in this optical semiconductor device, for example, the semiconductor element 108 is optically excited by a high-frequency signal supplied from the outside via the coaxial connector 107, and the excited laser light or the like is transmitted to or received from the optical fiber 113 through the translucent member 110. Transmission through the optical fiber 113 functions as a photoelectric conversion device that can transmit a large amount of information at high speed, and is widely used in the field of optical communication.
[0013]
[Patent Document 1]
JP 2002-141594 A
[Problems to be solved by the invention]
However, in the above-described conventional semiconductor element housing package 101, the center conductor 107c of the coaxial connector 107 is connected to the wiring conductor 102a on the circuit board 102 formed so that the impedance is the same as the impedance of the center conductor 107c of the coaxial connector 107. Are joined, the surface area of the center conductor 107c added to the surface area of the wiring conductor 102a at the portion where the center conductor 107c is joined to the wiring conductor 102a becomes the surface area of the conductor, and the capacitive component increases accordingly. As a result, the impedance is reduced at the junction, causing impedance mismatching. As a result, the reflection loss at the time of inputting / outputting a high-frequency signal increases, and the operability of the semiconductor element 108 is impaired. Had.
[0015]
In addition, since the length of the center conductor 107c protruding from the insulator 107b is not particularly considered, resonance of a high-frequency signal may occur in a portion of the center conductor 107c protruding from the insulator 107b. There is also a problem that the return loss increases and the operability of the semiconductor element 108 may be impaired.
[0016]
The present invention has been devised in view of the above problems, and an object of the present invention is to minimize a reflection loss generated at a junction between a wiring conductor on a circuit board and a center conductor of a coaxial connector when inputting and outputting a high-frequency signal. It is an object of the present invention to provide a semiconductor element storage package which can suppress the number of semiconductor elements and thereby improve the operability of the semiconductor element.
[0017]
[Means for Solving the Problems]
A semiconductor device housing package according to the present invention includes a base having a mounting portion on which a semiconductor element and a circuit board are mounted via a mounting base, and surrounding the mounting portion on the upper surface of the base. A frame body having a through hole formed in a side portion, a mounting base mounted on the mounting section, and the circuit mounted on the mounting base. A substrate, a cylindrical outer conductor, a center conductor provided on the center axis thereof, and an insulator interposed therebetween; and the center conductor fitted into the through hole and protruding from the insulator. And a coaxial connector connected to a wiring conductor on an upper surface of the circuit board, the circuit board having the wiring conductor on an upper surface of an insulating substrate formed by laminating a plurality of insulating layers, and Inner layer contact facing the wiring conductor between layers A semiconductor element housing package having a conductor, wherein the inner-layer ground conductor has a non-formed portion provided in a portion below a region where a lower side of the center conductor is connected to the wiring conductor; Wherein the length of the portion protruding from the insulator to the inside of the frame is less than a quarter of the wavelength of the high-frequency signal transmitted by the center conductor.
[0018]
Further, in the semiconductor device housing package according to the present invention, in the above configuration, a distance between the wiring conductor and the ground conductor on the same plane is increased above the non-formed portion.
[0019]
According to the package for housing a semiconductor element of the present invention, the center conductor of the coaxial connector is a wiring conductor having a grounded coplanar line structure above a non-formed portion provided on an inner layer ground conductor formed on an inner layer of the insulating substrate of the circuit board. The non-forming part can reduce the increase of the capacitive component between the conductor and the inner layer ground conductor due to the increase in the surface area of the conductor at the joint between the two parts, thereby suppressing the decrease in impedance. Can effectively suppress fluctuations in impedance at the junction between the wiring conductor on the circuit board and the center conductor of the coaxial connector. Can be kept very small.
[0020]
In addition, since the length of the central conductor at the portion protruding from the insulator to the inside of the frame is set to less than one-fourth of the wavelength of the high-frequency signal transmitted by the central conductor, resonance at this portion of the central conductor is prevented. Since the occurrence can be prevented, it is possible to effectively suppress the adverse effect such that the reflection loss increases.
[0021]
Furthermore, if the distance between the wiring conductor and the ground conductor on the same plane is made larger above the non-formed portion, the same surface area increases as the surface area of the conductor at the joint between the center conductor of the coaxial connector and the wiring conductor increases. Since the increase of the capacitive component between the ground conductor and the ground conductor can be reduced and the decrease in impedance can be suppressed, the impedance at the junction between the wiring conductor on the circuit board and the center conductor of the coaxial connector can be reduced. Fluctuations can be suppressed more effectively, and impedance can be matched to minimize the reflection loss that occurs during input / output of high-frequency signals.
[0022]
Thus, according to the semiconductor element housing package of the present invention, the reflection loss at the time of inputting / outputting a high-frequency signal can be made extremely small, and the operability of the mounted semiconductor element can be improved. it can.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
The package for housing a semiconductor element of the present invention will be described in detail below.
[0024]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a semiconductor element housing package of the present invention, and FIG. 2 is an enlarged plan view of a main part around a coaxial connector in the semiconductor element housing package shown in FIG. is there. FIG. 1 shows an example in which the semiconductor element housing package of the present invention is applied to an optical semiconductor element housing package. FIG. 2 shows a perspective view of the inside of the circuit board.
[0025]
In these figures, reference numeral 1 denotes a base 4 forming the bottom surface of the container main body, a frame 6 forming the side wall of the container main body, a coaxial connector 7 which is an input / output terminal of a high-frequency signal, a light-transmitting member 10, A semiconductor element storage package comprising a cylindrical optical fiber fixing member 14 to which the metal holder 12 is installed and fixed and the optical fiber 13 is attached.
[0026]
The base 4, the frame 6, the coaxial connector 7, the fixing member 14, the translucent member 10, and the lid 5 basically constitute a container for housing the optical semiconductor element 8 as a semiconductor element inside.
[0027]
Further, a metal holder 12 to which an optical isolator 11 and an optical fiber 13 are bonded with a resin adhesive or the like is fixed to the outer end surface of the fixing member 14 by YAG laser welding or the like.
[0028]
In the semiconductor element housing package 1, the coaxial connector 7 is mounted on a cylindrical outer conductor 7a, an insulator 7b made of borosilicate glass or the like filled in the outer conductor 7a, and a central portion of the insulator 7b. And a central conductor 7c provided on the central axis of the outer conductor 7a and conducting inside and outside the semiconductor element housing package 1.
[0029]
This coaxial connector 7 has a structure in which an insulator 7b is filled and interposed between an outer conductor 7a and a center conductor 7c, and its outer periphery, that is, the outer conductor 7a made of a metal material and the inner periphery of the through hole 6a. The surface and the center conductor 7c constitute a coaxial structure capable of impedance matching when transmitting a high-frequency signal.
[0030]
Further, the center conductor 7c protrudes from the insulator 7b toward the inside of the frame 6, and its tip end is mounted on the mounting base 3 and serves as a high-frequency signal transmission path on the upper surface. A circuit board for impedance matching and the like is formed of a ceramic substrate (insulating substrate) 2 of alumina ceramics or the like in which a wiring conductor 2a constituting a microstrip line is formed of a metallized metal layer or the like.
[0031]
In this example, the insulating substrate 2 of the circuit board is formed by laminating a plurality of insulating layers, and an inner layer ground conductor 2 'is formed in an inner layer between the insulating layers, and is formed on the upper surface so as to face the inner layer ground conductor 2'. The wiring conductor 2a is a coplanar line with a ground, having the same plane ground conductor 2b on both sides thereof and formed so as to have the same impedance as the center conductor 7c of the coaxial connector 7. It is electrically connected to the semiconductor element 8 via a bonding wire 15. The other end is joined to the distal end of the center conductor 7c of the coaxial connector 7, thereby having a function of electrically connecting the center conductor 7c and the optical semiconductor element 8. Further, the same-plane ground conductor 2b is electrically connected to the ground of the optical semiconductor element 8 via a bonding wire 15.
[0032]
If the wiring conductor 2a is made of a metallized metal layer, a metal paste obtained by adding an organic solvent and a solvent to a metal powder such as molybdenum (Mo), manganese (Mn), and tungsten (W) is used. It is formed by printing and applying a predetermined pattern on a ceramic green sheet to be an insulating substrate 2 of a circuit board by a screen printing method in advance, and firing it.
[0033]
In the semiconductor device housing package 1 of the present invention, the insulating substrate 2 of the circuit board has a wiring conductor on its inner layer below an area where the lower side of the center conductor 7c of the coaxial connector 7 is connected to the wiring conductor 2a on the upper surface thereof. A non-formed portion of the conductor is provided below the inner-layer ground conductor 2 'formed so as to face the inner conductor 2a, and the inner conductor 7' of the central conductor 7c of the coaxial connector 7 is located inside the frame 6 from the insulator 7b. It is important that the length of the protruding portion is less than a quarter of the wavelength of the high-frequency signal transmitted by the center conductor 7c.
[0034]
This is so that the main factor of the decrease in impedance at the joint between the wiring conductor 2a on the upper surface of the insulating substrate 2 and the center conductor 7c of the coaxial connector 7 is the same as the impedance of the center conductor 7c of the coaxial connector 7. When the center conductor 7c is joined to the formed wiring conductor 2a, the surface area of the conductor at the joint increases, and the capacitive component between the conductor and the inner-layer ground conductor 2 'increases. On the other hand, according to the semiconductor element housing package 1 of the present invention, the lower side of the center conductor 7c of the coaxial connector 7 is located below the region connected to the wiring conductor 2a on the upper surface of the circuit board. By providing a non-formed portion in the inner-layer ground conductor 2 ′, an increase in the capacitive component between the inner-layer ground conductor 2 ′ and the inner-layer ground conductor 2 ′ due to an increase in the surface area of the conductor at the joint is prevented. Because it can be obtained can be suppressed decrease in impedance, it is possible to suppress the occurrence of impedance mismatch to effectively suppress the fluctuation of impedance.
[0035]
Further, in the semiconductor element housing package of the present invention, the interval between the wiring conductor 2a and the same-plane ground conductor 2b on both sides thereof is opposed to the inner-layer ground conductor 2 'above the portion where the inner-layer ground conductor 2' is not formed. It is preferable that the gap is wider than the interval in the line portion having a predetermined impedance.
[0036]
This is because the center conductor 7c of the coaxial connector 7 is joined to the wiring conductor 2a, so that the surface area of the conductor at the joint increases and the capacitive component between the conductor and the same-plane ground conductor 2b increases. In this case, the impedance is reduced, whereas the distance between the wiring conductor 2a and the ground conductor 2b on the same plane is formed above the portion where the inner layer ground conductor 2 'is not formed, that is, on both sides of the joint between the wiring conductor 2a and the center conductor 7c. Is increased, it is possible to suppress an increase in a capacitive component between the conductor and the same-plane ground conductor 2b due to an increase in the surface area of the conductor at the joint, thereby suppressing a decrease in impedance. This is because it is possible to more effectively suppress the occurrence of impedance mismatching.
[0037]
Here, the size of the non-formed portion provided in a portion of the inner layer ground conductor 2 ′ below the region where the lower side of the center conductor 7 c of the coaxial connector 7 is connected to the wiring conductor 2 a on the upper surface of the insulating substrate 2, The distance between the wiring conductor 2a and the ground conductor 2b above the forming part depends on the frequency of the high-frequency signal transmitted by the center conductor 7c and the wiring conductor 2a, and is determined by the impedance of the wiring conductor 2a and the center conductor 7c. The increase in the surface area of the conductor at the joint where the lower side of the center conductor 7c is connected to the wiring conductor 2a increases the capacitive component between the inner-layer ground conductor 2 'and the same-plane ground conductor 2b. The contact between the non-formed portion and the wiring conductor 2a is increased by increasing the distance between the conductor and the same-surface ground conductor 2b so that the occurrence of impedance mismatching at the joint can be suppressed. Depending on the part specifications may be selected and set as appropriate to the size and spacing that can suppress the increase in the capacitive component in the joint.
[0038]
When the distance between the wiring conductor 2a and the same-plane grounding conductor 2b is increased above the portion where the inner-layer grounding conductor 2 'is not formed, the interval of the expanded portion is made to be abruptly stepped with respect to the wiring conductor 2a. Instead, as shown in FIG. 2, the change in the distance between the steps does not cause a problem such as the reflection of the high-frequency signal due to such a change in the step-like distance, thereby deteriorating the transmission characteristics of the high-frequency signal. It is desirable to provide a so-called tapered change portion so that the shape becomes continuous.
[0039]
In order to form the inner-layer ground conductor 2 ′ provided with such a non-formed portion in the inner layer of the insulating substrate 2, similarly to the wiring conductor 2 a, screen printing is performed in advance on a ceramic green sheet to be the insulating substrate 2 of the circuit board. It may be formed by printing and applying a predetermined pattern by a method, laminating with another ceramic green sheet, and firing.
[0040]
Also, regarding the coaxial connector 7, the length of the central conductor 7c of the portion protruding from the insulator 7b to the inside of the frame 6 is set to be less than ４ of the wavelength of the high-frequency signal transmitted by the central conductor 7c. As a result, resonance can be prevented from occurring at this portion of the center conductor 7c, and energy radiation of a high-frequency signal propagated by the center conductor 7c can be prevented from occurring, thereby preventing an increase in reflection loss. This is because it is possible to effectively suppress the deterioration of the high frequency transmission characteristics.
[0041]
As a result, the reflection loss at the time of inputting / outputting a high-frequency signal can be made very small, and the operability of the optical semiconductor element 8 is not impaired.
[0042]
The coaxial connector 7 has a function of electrically connecting an external electric circuit (not shown) and the optical semiconductor element 8 and closes a through hole 6 a formed in the frame 6 of the semiconductor element housing package 1. This also has the function of hermetically sealing the inside of the container body.
[0043]
The frame body 6 to which such a coaxial connector 7 is fitted is attached to the upper surface of the base body 4 so as to surround the mounting portion 9 by being joined via a brazing material such as silver brazing. .
[0044]
A through hole 6a for fitting the coaxial connector 7 is used on one side of the frame 6, and an optical transmission path for optically coupling the optical semiconductor element 8 and the optical fiber 13 is used on the opposite side. Through holes 6b are formed. The frame 6 has a thermal expansion coefficient of the base 4 in order to reduce the thermal strain caused by the connection with the base 4 and increase the bonding strength, and to provide electromagnetic shielding to the outside of the semiconductor element housing package 1. It is preferable to use a similar metal material such as an Fe-Ni-Co alloy or an Fe-Ni alloy. The frame 6 is manufactured by forming an ingot of, for example, an Fe—Ni—Co alloy into a frame by pressing.
[0045]
The through-hole 6 a formed on one side of the frame 6 is an attachment hole for attaching the coaxial connector 7 to the frame 6. Further, the through holes 6b formed on the other opposite side of the frame 6 are attachment holes for attaching the fixing member 14 to the frame 6. These through holes 6a and 6b are formed in predetermined positions, shapes, and dimensions by, for example, drilling a side portion of the frame body 6 with a drill.
[0046]
A cylindrical fixing member 14 is attached to the through hole 6 b of the frame 6, and a translucent member 10 is attached inside the fixing member 14. The fixing member 14 attached to the through-hole 6b of the frame 6 functions as a bonding medium when the metal holder 12 to which the optical isolator 11 and the optical fiber 13 are bonded is fixed to the frame 6, and an optical semiconductor element. 8 has a function of transmitting the excited light to the optical fiber 13.
[0047]
On the surface of the frame 6, a metal having excellent corrosion resistance and excellent wettability with the brazing material, specifically, a Ni layer having a thickness of 0.5 μm to 9 μm and an Au layer having a thickness of 0.5 μm to 9 μm are provided. Are preferably sequentially applied by a plating method. Thereby, the oxidizing corrosion of the frame 6 can be effectively prevented, and the coaxial connector 7 and the fixing member 14 can be firmly joined to the through holes 6a, 6b, respectively.
[0048]
The base 4 in the semiconductor element housing package 1 of the present invention serves as a support member for supporting the mounting base 3 on which the optical semiconductor element 8 and the circuit board are mounted, and heat generated from the optical semiconductor element 8. Functioning as a radiator plate for receiving through the mounting base 3 and dissipating it outside, and the optical semiconductor element 8 and the circuit board are mounted via the mounting base 3 at a substantially central portion of the upper surface thereof. It has a mounting portion 9. The mounting base 3 is mounted on the mounting portion 9 and is bonded and fixed via a low melting point brazing material such as Sn-Pb solder. Further, heat generated from the optical semiconductor element 8 is efficiently radiated from the base 4 to the outside via the mounting base 3 and the low melting point brazing material, thereby improving the operability of the optical semiconductor element 8. .
[0049]
The base 4 is made of a metal material such as an Fe-Ni-Co alloy or an Fe-Ni alloy, and is manufactured into a predetermined shape by subjecting the ingot to metal processing such as rolling or punching.
[0050]
A metal having excellent corrosion resistance and excellent wettability with the brazing material, specifically, a Ni layer having a thickness of 0.5 μm to 9 μm and an Au layer having a thickness of 0.5 μm to 9 μm are formed on the surface of the base 4. Are preferably sequentially applied by a plating method. Thereby, oxidation corrosion of the base 4 can be effectively prevented, and the mounting base 3 can be firmly adhered and fixed to the upper surface of the base 4 via the brazing material.
[0051]
A frame 6 is attached to the upper surface of the base 4 so as to surround the mounting section 9. The mounting base 3 and the optical semiconductor mounted on the frame 6 are mounted inside the frame 6. A space for accommodating the element 8 and the circuit board is formed.
[0052]
In the above description, the case has been described in which the base 4 and the frame 6 are formed separately and joined, but the base 4 and the frame 6 are integrally formed, for example, metal. -It may be manufactured by an injection mold (MIM) method or the like.
[0053]
The translucent member 10 closes the internal space of the fixing member 14, maintains the airtightness of the container including the base 4, the frame 6, and the lid 5, and passes the optical semiconductor through the internal space of the fixing member 14. It has a function of transmitting light from the element 8 or light to the optical semiconductor element 8 to the optical fiber 13 attached to and connected to the fixing member 14 as it is, or to transmit the light from the optical fiber 13.
[0054]
The translucent member 10 is made of, for example, sapphire (single-crystal alumina) having a coefficient of thermal expansion of 4 × 10 ⁻⁶ / ° C. to 12 × 10 ⁻⁶ / ° C. (room temperature to 400 ° C.), silicon oxide, or lead oxide. It is formed of a lead-based amorphous glass whose main component is borosilicate amorphous glass whose main component is boric acid or silica sand. Since these amorphous glasses have no crystal axis, when light is transmitted and received between the optical semiconductor element 8 and the optical fiber 13 through the translucent member 10, the light is transmitted. The light is transmitted and received between the optical semiconductor element 8 and the optical fiber 13 without causing birefringence in the optical member 10, and the transmission and reception of light between the optical semiconductor element 8 and the optical fiber 13 becomes highly efficient. This is preferable in that the signal transmission efficiency increases.
[0055]
Further, the light transmitting member 10 can be formed into a shape such as a spherical shape, a hemispherical shape, a convex lens shape, a rod lens shape, and the like, and external light such as laser light is transmitted through the optical fiber 13 and input to the optical semiconductor element 8. The optical fiber 13 is used as a condensing member for inputting light such as laser light output from the optical semiconductor element 8 to the optical fiber 13.
[0056]
Even if the transmissive member 10 has a thermal expansion coefficient different from that of the frame 6, the fixing member 14 absorbs and relaxes the stress due to the difference in thermal expansion, so that the crystal axis has a certain direction due to such stress. It is difficult for the refractive index of the light to change due to the alignment. Therefore, by using such a translucent member 10, the light coupling efficiency between the optical semiconductor element 8 and the optical fiber 13 can be increased.
[0057]
Further, the attachment of the translucent member 10 to the fixing member 14 is performed, for example, by previously coating a metal layer such as a metallized metal layer on the outer peripheral portion of the translucent member 10, and attaching this metal layer to the fixing member 14. And a lower melting point brazing material such as Au—Sn alloy solder having a melting point of about 200 ° C. to 400 ° C. In this case, since the attachment of the translucent member 10 to the fixing member 14 is performed by brazing of an Au-Sn alloy or the like, the reliability of the attachment is extremely high, and thus the fixing member 14 and the translucent member are connected. Hermetic sealing of the container accommodating the optical semiconductor element 8 at the attachment portion with the member 10 is completed, and the optical semiconductor element 8 accommodated in the container can be normally and stably operated for a long time.
[0058]
The mounting base 3 in the semiconductor element storage package 1 of the present invention is made of a metal material having high thermal conductivity such as silicon (Si) or a Cu-W alloy, and supports the optical semiconductor element 8 and the circuit board. In addition to functioning as a support member, it functions as a heat transfer medium for transmitting heat from the optical semiconductor element 8 to the base 4. Further, by setting the height as appropriate, it has a function of matching the optical axes of the translucent member 10 and the optical semiconductor element 8.
[0059]
A lid 5 made of a metal material such as an Fe—Ni—Co alloy or an Fe—Ni alloy, or a ceramic material such as an alumina ceramic is attached to the upper surface of the frame 6. The optical semiconductor element 8 is hermetically sealed together with the circuit board inside a container including the frame 6 and the lid 5. In order to secure good airtightness, the lid 5 is attached to the upper surface of the frame 6 by, for example, a welding method such as a seam welding method or a YAG laser welding method, or a low melting point such as an Au—Sn alloy solder. The bonding is performed by a brazing method using a brazing material or the like.
[0060]
Thus, according to the semiconductor device housing package 1 of the present invention, the optical semiconductor device 8 and the circuit board are mounted and fixed on the mounting portion 9 of the base 4 via the mounting base 3 and the optical semiconductor device 8 is mounted. Each electrode is electrically connected to the wiring conductor 2a on the circuit board via the bonding wire 15 and electrically connected to the center conductor 7c of the coaxial connector 7, and then the lid 5 is attached to the upper surface of the frame 6. The optical semiconductor element 8 is housed together with the circuit board in a container including the base 4, the frame 6, and the lid 5, and finally, the optical isolator 11 is attached to the fixing member 14 attached to the frame 6. By welding and attaching the metal holder 12 with the optical fiber 13 attached thereto, an optical semiconductor device as a final product is obtained.
[0061]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the same-plane ground conductor 2b may be configured to obtain a stable ground state by being electrically connected to the inner-layer ground conductor 2 ′ via a through conductor formed inside the insulating substrate 2. .
[0062]
【The invention's effect】
According to the package for housing a semiconductor element of the present invention, the center conductor of the coaxial connector is joined to the wiring conductor above the non-formed portion provided on the inner-layer ground conductor formed on the inner layer of the insulating substrate of the circuit board. Therefore, the increase in the capacitive component between the conductor and the inner-layer ground conductor due to the increase in the surface area of the conductor at the joint portion between the two can be reduced by the non-formed portion, and the decrease in impedance can be suppressed. It is possible to effectively suppress the fluctuation of impedance at the junction between the upper wiring conductor and the center conductor of the coaxial connector, match the impedance, and minimize the reflection loss that occurs when inputting and outputting high-frequency signals. Can be suppressed.
[0063]
In addition, since the length of the central conductor at the portion protruding from the insulator to the inside of the frame is set to less than one-fourth of the wavelength of the high-frequency signal transmitted by the central conductor, resonance at this portion of the central conductor is prevented. Since the occurrence can be prevented, it is possible to effectively suppress the adverse effect such that the reflection loss increases.
[0064]
Furthermore, if the distance between the wiring conductor and the ground conductor on the same plane is made larger above the non-formed portion, the same surface area increases as the surface area of the conductor at the joint between the center conductor of the coaxial connector and the wiring conductor increases. Since the increase of the capacitive component between the ground conductor and the ground conductor can be reduced and the decrease in impedance can be suppressed, the impedance at the junction between the wiring conductor on the circuit board and the center conductor of the coaxial connector can be reduced. Fluctuations can be suppressed more effectively, and impedance can be matched to minimize the reflection loss that occurs during input / output of high-frequency signals.
[0065]
As a result, according to the semiconductor element housing package of the present invention, it is possible to minimize the reflection loss generated at the joint between the wiring conductor on the circuit board and the center conductor of the coaxial connector during input and output of a high-frequency signal. Thus, a semiconductor element housing package in which the mounted semiconductor element has good operability can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a semiconductor device housing package according to the present invention.
2 is an enlarged plan view of a main part around a coaxial connector in the package for housing a semiconductor element shown in FIG. 1;
FIG. 3 is a cross-sectional view showing an example of a conventional semiconductor device housing package.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Package 2 for semiconductor element accommodation ... Insulating board 2 '... Inner layer ground conductor 2a ... Wiring conductor 2b ... Same plane ground conductor 3 ... Mounting base 4 ... Base 5 Lid 6 Frame 6a Through hole 6b for mounting coaxial connector 7 Through hole 7 for optical transmission line 7 Coaxial connector 7a Outer conductor 7b · Insulator 7c · · · Central conductor 8 · · · Optical semiconductor element (semiconductor element)
9 mounting section 10 translucent member 11 optical isolator 12 metal holder 13 optical fiber 14 fixing member 15 bonding wire

Claims (2)

A base having a mounting portion on which a semiconductor element and a circuit board are mounted via a mounting base; and a side portion attached to the upper surface of the base so as to surround the mounting portion. A frame body having a through-hole formed therein, the mounting base mounted on the mounting portion and the circuit board mounted on the mounting base, and a cylindrical outer peripheral conductor and the same. A lower side of the center conductor, which is formed of a center conductor provided on a center axis and an insulator interposed therebetween and is fitted in the through hole and protrudes from the insulator, is provided on a wiring on an upper surface of the circuit board. And a coaxial connector connected to a conductor, wherein the circuit board has the wiring conductors on the upper surface of an insulating substrate formed by laminating a plurality of insulating layers and the same-surface ground conductors on both sides thereof, and between the insulating layers. Having an inner-layer ground conductor facing the wiring conductor In the semiconductor device storage package, the inner-layer ground conductor has a non-formed portion provided in a portion below a region where a lower side of the center conductor is connected to the wiring conductor, and the insulation of the center conductor is provided. A semiconductor element housing package, wherein a length of a portion protruding from the body toward the inside of the frame is less than a quarter of a wavelength of a high frequency signal transmitted by the center conductor. 2. The package for accommodating a semiconductor element according to claim 1, wherein a distance between the wiring conductor and the ground conductor on the same plane is increased above the non-formed portion.

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