JP2006179775A - Semiconductor element housing package and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor element housing package that reduces reflection loss in a bonding wire and prevents an effect on an external electric circuit, and to provide a semiconductor device. <P>SOLUTION: The semiconductor element housing package comprises a metal substrate 1 that has a semiconductor element S mounting part 1a on the center of the top face thereof, and a through hole 1b formed around the mounting part 1a from the top face to the bottom face; and a lead terminal 3 which is inserted through the through-hole 1b, is fixed via a sealing member 2 in such a way that at least a lower end thereof projects from the through hole 1b, and an upper end thereof is electrically connected to the electrode of the semiconductor element S. A conductive projection 7 is formed in a standing state along the upper end of the lead terminal 3 in connection with an earth potential near the through hole 1b on the top face of the metal substrate 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor element housing package for housing a semiconductor element such as an optical semiconductor element used in the field of optical communication and the like, and a semiconductor device using the same.

  In recent years, the demand for high-speed communication at a transmission distance of 40 km or less has been increasing rapidly, and research and development on high-speed and large-capacity information transmission is underway. In particular, increasing the speed of semiconductor devices that receive and transmit optical signals using optical communication devices has attracted attention, and research and development as an issue to improve transmission capacity is to increase the output and speed of optical signals by semiconductor devices. Has been.

  The optical output of the conventional semiconductor device is about 0.2 to 0.5 mW, and the driving power of the semiconductor element is about 5 mW. However, in a semiconductor device having a higher output, the optical output has become a level of 1 mW, and the driving power of the semiconductor element is required to be 10 mW or more. Furthermore, although the transmission capacity of the conventional semiconductor device was about 2.5 Gbps, it has been improved to about 10 Gbps in recent years, and there is a demand for higher output and higher speed of the semiconductor device.

  A package for housing a semiconductor element (hereinafter simply referred to as a package for housing a semiconductor element) containing a semiconductor element including an optical semiconductor element such as an LD (Laser Diode) or a PD (Photo Diode) used in a conventional optical communication device. A package) and a semiconductor device using the same are shown in FIGS. Here, FIG. 7 is a plan view seen from the inside of the package with the lid of the semiconductor device removed, and FIG. 8 is a cross-sectional view of the package of FIG.

  The conventional package has iron (Fe) − having a mounting portion 11a for the semiconductor element S ′ at the center of the upper surface and a through hole 11b having a diameter of 0.5 to 2 mm formed from the upper surface to the lower surface around the mounting portion 11a. A disc-shaped metal substrate 11 made of a metal such as a nickel (Ni) -cobalt (Co) alloy or an Fe-manganese (Mn) alloy is inserted into the through hole 11b so that at least the lower end protrudes from the through hole 11b. A lead terminal 13 made of a metal such as an Fe-Ni-Co alloy or Fe-Ni alloy, whose upper end is electrically connected to the electrode of the semiconductor element S ', And a ground lead terminal 13a that is inserted into the through hole 11b and electrically connected to the metal substrate 11.

  Then, the semiconductor element S ′ is mounted on the mounting portion 11a of the package, and the electrode is electrically connected to the upper end portion of the lead terminal 13 so that the semiconductor element S ′ is covered on the upper surface of the metal substrate 11. By joining the lid 16, a semiconductor device is obtained.

  The metal substrate 11 and the lead terminal 13 are joined via an insulating glass containing borosilicate as a main component, and the metal substrate 11 and the lead terminal 13 are electrically insulated by the insulating glass. The ground lead terminal 13a is fixed to the metal substrate 11 by brazing with a high melting point brazing material such as silver (Ag) -copper (Cu), and a ground conductor layer of an external electric circuit (not shown) and lead (Pb) -tin. (Sn) It is electrically connected with a solder material such as solder. The semiconductor element S ′ is brazed and fixed to the metal substrate 11 with a low melting point brazing material such as gold (Au) —Sn having a melting point of 200 to 400 ° C., and the electrode of the semiconductor element S ′ is bonded via the bonding wire 14. And electrically connected to the lead terminal 13.

  On the upper surface of the metal substrate 11, a lid 16 made of an Fe-Ni-Co alloy or the like is provided on the outer peripheral portion within 1 mm in width from the outer peripheral end for the purpose of protecting the semiconductor element S '. Or it becomes a semiconductor device as a product by joining by brazing.

  As shown in FIG. 8, the lid 16 is provided with an optical fiber 15 fixed to a portion facing the semiconductor element S ′ or a window through which light is transmitted at a portion facing the semiconductor element S ′. Sometimes.

This semiconductor device is used for large-capacity optical communication and the like, and a semiconductor device S ′ is optically excited by a drive signal supplied from an external electric circuit (not shown), and the excited light is returned to an optical isolator for preventing return light ( The optical fiber 15 is transmitted / received through the optical fiber 15 via the optical fiber 15 (not shown). It is often used for communications with a transmission capacity of 2.5 Gbps (Gigabit per second) or less over a transmission distance of 40 km or less.
JP-A-8-130266

  However, when a semiconductor element S ′ that is driven by a high-frequency signal of 10 GHz or more is mounted on the conventional package, an inductive component in the bonding wire 14 of the semiconductor element S ′ increases, and reflection on the bonding wire 14 occurs. There is a problem that the loss increases and the semiconductor element S ′ malfunctions.

  This is because in the conventional package, the characteristic impedance of the bonding wire 14 is slightly shifted from the value of the characteristic impedance in the other part and has an inductive component.

  Accordingly, the present invention has been completed in view of the above-described conventional problems, and an object thereof is to reduce a reflection loss in a bonding wire and prevent a semiconductor element storage package from affecting the characteristics of an external electric circuit. Another object is to provide a semiconductor device.

  The semiconductor element storage package of the present invention includes a metal substrate having a semiconductor element mounting portion at the center of the upper surface and a through-hole formed in the periphery of the mounting portion from the upper surface to the lower surface, and inserted into the through hole. A semiconductor element housing having a lead terminal which is fixed through a sealing material so that at least a lower end portion protrudes from the through-hole, and an upper end portion is electrically connected to an electrode of the semiconductor element In the package for use, on the upper surface of the metal substrate, in the vicinity of the through-hole, a conductive projection is provided that is connected to the ground potential and is erected along with the upper end of the lead terminal. And

  In the package for housing a semiconductor element according to the present invention, it is preferable that the projection is formed in an arc shape when seen in a plan view.

  In the package for housing a semiconductor element according to the present invention, it is preferable that the protrusion is formed around the lead terminal so as to surround the entire circumference.

  The semiconductor device of the present invention includes a semiconductor element storage package of the present invention, a semiconductor element mounted on the mounting portion and having an electrode electrically connected to the lead terminal, and a sealing member covering the semiconductor element. It is characterized by having.

  According to the package for housing a semiconductor element of the present invention, the conductive protrusions which are connected to the ground potential on the upper surface of the metal substrate in the vicinity of the through hole and are erected along with the upper end portion of the lead terminal. As a result, the protruding portion approximates the potential of the grounding electrode of the semiconductor element, and the ground potential of the connection portion between the upper end portion of the lead terminal and the bonding wire can be strengthened by the protruding portion, and transmission characteristics are improved. can do. In addition, by connecting the protrusion directly to the grounding electrode of the semiconductor element with a bonding wire, the potential difference between the protrusion and the grounding electrode of the semiconductor element becomes extremely small. The ground potential for the connection portion with the wire can be further strengthened.

  As a result, the inductive component generated in the bonding wire that electrically connects the lead terminal and the semiconductor element can be reduced, and the characteristic impedance of the bonding wire can be brought close to the value of the characteristic impedance of other parts. It is possible to reduce the reflection loss at and to affect the characteristics of the external electric circuit.

  According to the package for housing a semiconductor element of the present invention, since the projecting portion has an arc shape in plan view, the projecting portion has a better ground potential than the connection portion between the upper end portion of the lead terminal and the bonding wire. Strengthening can be performed, reflection loss can be further reduced, and influence on the characteristics of the external electric circuit can be prevented.

  According to the package for housing a semiconductor element of the present invention, since the protruding portion is formed so as to surround the entire circumference of the lead terminal, the connecting portion between the upper end portion of the lead terminal and the bonding wire is coaxially formed by the protruding portion. By surrounding, the ground potential can be strengthened very well, and the transmission characteristics can be made extremely high.

  According to a semiconductor device of the present invention, the semiconductor device housing package described above, a semiconductor device mounted on a mounting portion and having an electrode electrically connected to a lead terminal, and a sealing member covering the semiconductor device are provided. Therefore, even when the semiconductor device is driven by a high-frequency signal, the semiconductor device can be provided in which the high-frequency signal is reflected by the bonding wire and the semiconductor element does not malfunction.

  Next, a semiconductor element housing package and a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an optical semiconductor element storage package and an optical semiconductor device using an optical semiconductor element as a semiconductor element, as an example of an embodiment of a semiconductor element storage package and a semiconductor device according to the present invention. 1 is a plan view seen from the inside of the package with the lid of the semiconductor device removed, FIG. 2 is a cross-sectional view taken along the line AA ′ of the semiconductor device of FIG. 1, and FIG. 3 is B of the semiconductor device of FIG. FIG.

  In these figures, 1 is a metal substrate, 1a is a semiconductor element mounting portion, 2 is a sealing material, 3 is a lead terminal, and 7 is a protrusion, and these basically constitute the package of the present invention. The package, the semiconductor element S, and the lid 6 basically constitute a semiconductor device of the present invention.

  1, 2 and 3 show an example in which one semiconductor element S is mounted and four through holes 1b are formed. However, a plurality of semiconductor elements S may be mounted. Further, the number of through holes 1b is not limited to four, and may be four or more or four or less.

  The metal substrate 1 has a mounting portion 1a for the semiconductor element S at the center of the upper surface and has a function of radiating heat generated by the mounted semiconductor element S to the outside of the package. And a through hole 1b having a diameter of 1.15 to 2.65 mm formed from the bottom surface to the bottom surface. Moreover, the shape of the metal substrate 1 is, for example, a disc shape having a diameter of 3.0 to 6.0 mm, a semicircular shape obtained by cutting a part of the circumference having a radius of 1.5 to 8.0 mm, a square plate shape having a side of 3.0 to 15 mm, and the like. The plate has a thickness of 0.5 to 2 mm.

  Such a metal substrate 1 is made of a metal such as an Fe—Ni—Co alloy or an Fe—Mn alloy. For example, when the metal substrate 1 is made of an Fe—Mn alloy, the ingot (lumb) is rolled or punched. It is manufactured in a predetermined shape by applying a conventionally well-known metal processing method.

  Further, a Ni layer having a thickness of 0.5 to 9 μm and an Au layer having a thickness of 0.5 to 5 μm, which are excellent in corrosion resistance and excellent in wettability with a brazing material, are sequentially deposited on the surface of the metal substrate 1 by a plating method. It is good. Thereby, it is possible to effectively prevent the metal substrate 1 from being oxidatively corroded and to braze each component to the metal substrate 1 satisfactorily.

  The thickness of the metal substrate 1 is preferably 0.5 mm or more and 2 mm or less. When the thickness is less than 0.5 mm, when the lid body 6 to be described later is bonded to the upper surface of the metal substrate 1, the metal substrate 1 is easily bent and deformed depending on the bonding conditions such as the bonding temperature, and the thickness exceeds 2 mm. As a result, the thickness of the package or semiconductor device becomes unnecessarily thick, making it difficult to reduce the size.

  The lead terminal 3 is inserted into the through hole 1b formed in the metal substrate 1, and is fixed via the sealing material 2 so that at least the lower end portion protrudes from the through hole 1b. The upper end portion of the metal substrate 1 of the lead terminal 3 is electrically connected to the electrode of the semiconductor element S via the bonding wire 4 so that the lead terminal 3 is connected to the semiconductor element S and an external electric circuit (not shown). The function to transmit input / output signals between. The lead terminal 3 is fixed via the sealing material 2 so that at least the lower end portion protrudes from the through hole 1b by about 1 to 20 mm, and the upper end portion protrudes from the through hole 1b by about 0 to 2 mm.

  Since the upper end portion of the lead terminal 3 is electrically connected to the electrode of the semiconductor element S, the through hole 1b is disposed at a position near the periphery of the mounting portion 1a, for example, 0.1 to 5 mm in plan view distance from the mounting portion 1a. Formed in position. When the through-hole 1b is disposed at a position near the periphery of the mounting portion 1a, the length of the bonding wire 4 connected to the electrode of the semiconductor element S can be shortened, so that the influence of the inductive component on the bonding wire 4 is reduced. Can do.

  The lead terminal 3 is made of a metal such as an Fe—Ni—Co alloy or an Fe—Ni alloy. For example, when the lead terminal 3 is made of an Fe—Ni—Co alloy, the ingot (lumb) is rolled or punched. By applying a conventionally known metal processing method, a wire having a length of 1.5 to 22 mm and a diameter of 0.1 to 1 mm is manufactured.

  The sealing material 2 is made of an inorganic material such as glass or ceramics, and has a function of securing an insulation interval between the lead terminal 3 and the metal substrate 1 and fixing the lead terminal 3 to the through hole 1 b of the metal substrate 1. .

  When the sealing material 2 is made of glass, the inner diameter is larger than the outer diameter of the lead terminal 3, and the outer diameter is smaller than the inner diameter of the through hole 1b of the metal substrate 1. The lead terminal 3 is inserted into the hole 1b, the lead terminal 3 is inserted into the sealing material 2, and then heated to a predetermined temperature to melt the sealing material 2, so that the lead terminal 3 is coaxial and sealed. The package of the present invention is manufactured in which the lead terminal 3 embedded in the material 2 and inserted through the through hole 1b is airtightly fixed to the through hole 1b.

  According to the package of the present invention, the conductive protrusion 7 that is connected to the ground potential on the upper surface of the metal substrate 1 in the vicinity of the through hole 1 b and is erected along with the upper end of the lead terminal 3 is provided. The formation of the bonding wire for grounding in the vicinity of the bonding wire 4 that electrically connects the semiconductor element S and the lead terminal 3 to the protruding portion 7 and the semiconductor element S can be achieved. In general, the bonding wire 7 has a high inductive component, and the characteristic impedance shifts slightly. In order to reduce this inductive component, a bonding wire for grounding is arranged in the vicinity to reduce the inductive component.

  The protrusion 7 of the present invention is provided on the upper surface of the metal substrate 1 in the vicinity of the through hole 1b so as to be connected to the ground potential. This vicinity is a range in which the lead terminal 3 can be electrically affected. Specifically, the distance between the lead terminal 3 and the protrusion 7 is preferably 0.05 to 1 mm. If it exceeds 1 mm, it is difficult to strengthen the ground potential with respect to the lead terminal 3. Moreover, if it is less than 0.05 mm, the lead terminal 3 and the protrusion part 7 will be easy to contact.

  The protrusion 7 is made of an Fe—Ni—Co alloy, Fe—Ni alloy, or the like, and is fixed to the metal substrate 1 by brazing with a brazing material such as Au—Sn having a melting point of 200 to 400 ° C. Preferably, the upper end thereof is electrically connected to the grounding electrode of the semiconductor element S via the bonding wire 4. The protrusion 7 may have a shape in which the metal substrate 1 and the ingot (lumb) are integrated by applying a conventionally known metal processing method such as rolling or punching.

  The semiconductor element S is fixed to the mounting portion 1a by brazing with a brazing material such as Au—Sn having a melting point of 200 to 400 ° C. After that, the electrode is connected to the upper end portion of the lead terminal 3 via the bonding wire 4. Is electrically connected. Examples of the semiconductor element S include LD (laser diode) and PD (photodiode).

  Then, a lid 6 made of Fe—Ni alloy, Fe—Ni—Co alloy, Fe—Mn alloy or the like is attached to the outer peripheral portion within a width of about 1 mm from the outer peripheral edge of the upper surface of the metal substrate 1 by YAG laser welding, seam. By joining by welding or brazing, the semiconductor element S is hermetically sealed and a semiconductor device is obtained.

  In such a lid 6, an optical fiber 5 and an optical isolator (not shown) for preventing return light may be bonded to a portion facing the semiconductor element S with a resin adhesive. Or the window which permeate | transmits light may be formed in the site | part facing the semiconductor element S. FIG.

  Furthermore, a plurality of lid bodies 6 having windows for transmitting light and lid bodies 6 to which optical fibers 5 are fixed may be joined.

  In addition, various shapes of window members such as a flat plate, a ball lens, and an aspherical lens may be joined to the window of the lid 6 with a low-melting glass or the like. The light emitted from the semiconductor element S can be collected by this window member.

  When the lid 6 is made of, for example, an Fe—Mn alloy, the ingot (lumb) is manufactured by applying a conventionally known metal processing method such as rolling or punching.

  According to the semiconductor device of the present invention, since the semiconductor element storage package of the present invention is provided, even if the semiconductor device is driven with a high-frequency signal of 10 GHz or more, the high-frequency signal is converted into an electromagnetic wave from the lid 6. A semiconductor that does not affect the characteristics of the external electric circuit because it suppresses unwanted radiation and prevents the electromagnetic wave from distorting the signal waveform of the external electric circuit placed around the semiconductor device. It can be a device.

  Thus, according to the semiconductor element housing package and the semiconductor device of the present invention, the metal cylindrical member 4 which is coaxial with the lead terminal 3 and embedded in the sealing material 2 in the through hole 1b of the metal substrate 1 is provided. Since it is fixed so as to be insulated through the metal substrate 1 and the sealing material 2, even if the semiconductor device is driven with a high frequency signal of 10 GHz or more, it is induced by a high frequency current due to the charge of the high frequency signal flowing through the lead terminal 3. The generated high-frequency current can be prevented from flowing to the metal substrate 1 and the lid 6, and the high-frequency current is radiated as an electromagnetic wave from the lid 6 and flows into an external electric circuit arranged around the semiconductor device. Therefore, the semiconductor element storing package and the semiconductor device capable of stably operating the external electric circuit are obtained.

  The semiconductor device of the present invention and a comparative sample were manufactured and the results were compared.

  An evaluation semiconductor device to be a semiconductor device of the present invention was manufactured as follows. First, a cylindrical mounting portion 1a having a thickness of 1.5 mm and a diameter of 3.0 mm is cut by a cutting process on a plate material having a thickness of 1.0 mm and a diameter of 5.6 mm made of an SPC (Steel Plate Cold) material of Fe99.6% -Mn0.4%. A through-hole 1b having a diameter of 0.7 mm was formed in the center of the provided metal substrate 1 by punching. The sealing material 2 made of low-melting glass formed into a cylindrical shape having a length of 1.0 mm, an inner diameter of 0.3 mm and an outer diameter of 0.7 mm in the through hole 1b of the metal substrate 1 has a length of 15 mm made of Fe68% -Ni42% alloy. X A lead terminal 3 having a diameter of 0.3 mm was inserted, and the through-hole 1a was hermetically sealed by melting glass in a furnace at 700 ° C.

  Furthermore, a Ni layer having a thickness of 2 μm and an Au layer having a thickness of 2 μm were sequentially deposited on the exposed surfaces of the metal substrate 1 and the lead terminals 3 by a plating method. Thereafter, a projection 7 having a size of 0.2 mm × 0.2 mm × 0.5 mm in height made of a laser diode serving as a semiconductor element S and a Fe68% -Ni42% alloy is brazed to the mounting portion 1a of the metal substrate 1 with an Au—Sn brazing material After that, the electrode of the semiconductor element S and the upper end portion of the lead terminal 3 were electrically connected by a bonding wire.

  Then, a cap-shaped lid body 6 made of Fe—Ni—Co alloy having an inner diameter of 3.9 mm, an outer diameter of 4.2 mm, and a height of 2.4 mm is joined to the outer peripheral portion of the upper surface of the metal substrate 1 by seam welding. A semiconductor device for evaluation was fabricated by hermetically sealing.

  Next, as another embodiment of the present invention, a projection 7 having an arc shape with an inner diameter of 0.7 mm, an outer diameter of 1.3 mm, and a height of 0.5 mm was produced.

  Next, a conventional semiconductor device for comparison was prepared. In the conventional semiconductor device, the lead terminal 13 is bonded and fixed to the 0.7 mm through-hole 11b formed in the metal substrate 11 via the sealing material 12, and the protrusion 7 is not provided. It is the same as the semiconductor device for evaluation.

The sample was simulated by a simulator (HFSS, manufactured by Ansoft Corporation), and the reflection loss (S11) at that time was compared. The frequency of simulation is 1 to 20 GHz, and Table 1 shows the worst reflection loss values in that range.

  As shown in Table 1, the reflection loss is reduced by providing the protrusion 7.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the present invention. For example, it can be used for low-speed communication such as 2.5 Gbps.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a semiconductor element storage package and a semiconductor device according to an embodiment of the present invention, with a lid removed. FIG. 2 is a cross-sectional view taken along line A-A ′ of the semiconductor element storage package and the semiconductor device of FIG. 1. FIG. 2 is a cross-sectional view taken along line B-B ′ of the semiconductor element storage package and the semiconductor device of FIG. 1. It is the top view in the state which removed the cover body, showing the other form of embodiment of the package for semiconductor element accommodation of this invention, and a semiconductor device. FIG. 5 is a cross-sectional view taken along line A-A ′ of the semiconductor element storage package and the semiconductor device of FIG. 4. FIG. 5 is a cross-sectional view taken along line B-B ′ of the semiconductor element storage package and the semiconductor device of FIG. 4. It is a top view in the state where a conventional semiconductor element storage package and a lid of a semiconductor device were removed. FIG. 8 is a cross-sectional view taken along line A-A ′ of the semiconductor element storage package and the semiconductor device of FIG. 7.

Explanation of symbols

1 .... Metal substrate 1a ... Mounting part 1b ... Through hole 2 .... Encapsulant 3 .... Lead terminal 6 ··················································· Semiconductor element

Claims (4)

A metal substrate having a semiconductor element mounting portion in the center of the upper surface and having a through hole formed in the periphery of the mounting portion from the upper surface to the lower surface, and inserted through the through hole, at least a lower end portion extending from the through hole In a package for housing a semiconductor element, wherein the upper end of the package is fixed through a sealing material so as to protrude, and the lead terminal is electrically connected to the electrode of the semiconductor element. A package for housing a semiconductor element, characterized in that, in the vicinity of the through hole, a conductive protrusion is formed which is connected to the ground potential and is erected in parallel with the upper end of the lead terminal. The package for housing a semiconductor element according to claim 1, wherein the projecting portion has an arc shape when viewed from above. 3. The package for housing a semiconductor element according to claim 1, wherein the protruding portion is formed around the lead terminal so as to surround the entire circumference. A package for housing a semiconductor element according to any one of claims 1 to 3, a semiconductor element mounted on the mounting portion and having an electrode electrically connected to the lead terminal, and a sealing member covering the semiconductor element And a semiconductor device.

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