JP2005039168A - Ceramic container and tantalum electrolytic capacitor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic container and a tantalum electrolytic capacitor capable of reducing signal transmission loss without impairing hermeticity even when the tantalum electrolytic capacitor is exposed to a high temperature.
A step 1c-A is formed between one inner side surface and a bottom surface of a concave portion 1a in a central portion of an upper surface, and first and second conductor layers 4a and 4b are provided on the lower surface independently of each other. The ceramic base 1, the first metallized layer 2a formed in the notch 2 formed in the step 1c-A, the second metallized layer 1b formed on the bottom surface of the recess 1a, and the side surface of the ceramic base 1 And first and second side conductors 4c and 4d formed on the inner surface of the groove formed in the vertical direction, and the first metallized layer 2a includes the first internal wiring 3a and the first side conductor 4c. Are electrically connected to the first conductor layer 4a, and the second metallized layer 1b is electrically connected to the second internal wiring 3b, the second side conductor 4d, and the second conductor layer 4b. Has been.
[Selection] Figure 1

Description

  The present invention relates to a tantalum electrolytic capacitor used for a ceramic container and an electronic circuit, and more particularly to a tantalum electrolytic capacitor configured using a ceramic container.

  A surface mount type tantalum electrolytic capacitor is known as a conventional resin-encapsulated solid electrolyte capacitor. This tantalum electrolytic capacitor is used in large quantities in a wide range of fields including communication equipment such as mobile phones, AV equipment such as digital cameras, computer equipment such as personal computers, and automobile equipment such as airbags and antilock brakes. Applications include power supply smoothing circuits, computer backups, timer circuits that use the charging / discharging time of tantalum electrolytic capacitors, and high-frequency filters, which are indispensable electronic components for the above-mentioned devices.

  Such a tantalum electrolytic capacitor includes a tantalum electrolytic capacitor element portion, a lead frame, and an exterior resin that hermetically seals the lead frame, and the lead frame generally has a strength such as an iron (Fe) -nickel (Ni) alloy. Is used, and as the exterior resin, an epoxy resin or the like is used because of its good heat resistance and moisture resistance.

  A conventional tantalum electrolytic capacitor of this type will be described below with reference to FIG. FIG. 5 is a cross-sectional view showing the structure of a conventional tantalum electrolytic capacitor. In FIG. 5, 11 is a tantalum electrolytic capacitor, B is a tantalum electrolytic capacitor element, C is an anode lead, and the tantalum electrolytic capacitor element B is made of tantalum or the like. One end portion of the anode lead C is embedded and the other end portion protrudes from the side surface. A sintered body 12 obtained by sintering a molded body obtained by solidifying tantalum powder is sintered on a dielectric oxide film layer ( (Not shown), a solid electrolyte layer (not shown) is formed outside the oxide film layer, and then the cathode layer 12a is formed on the outer periphery.

  The other end of the anode lead C is welded to the lead frame 13, and the lead frame 13 protrudes from the exterior resin 14 and is bent along the outer shape of the exterior resin 14 to reach the lower surface. Is done. Further, the lead frame 13 is bonded onto the cathode layer 12a via the conductive bonding material 15, and protrudes from the outer resin 14 and is bent along the outer shape of the outer resin 14 to reach the lower surface of the outer resin 14. The cathode terminal 13b for connection is used. In order to bend the lead frame 13 to be a connection terminal for both poles, and to be able to be bent at the same time, the lead frame 13 has a structure that is protruded in both directions from the same height of the opposite side surfaces of the exterior resin 14. Yes. As the exterior resin 14, an epoxy resin is used because of its excellent heat resistance, moisture resistance, and the like.

  Next, a method for manufacturing the tantalum electrolytic capacitor 11 will be described. First, the tantalum electrolytic capacitor element B is mounted on the fixed portion 16 of the tantalum electrolytic capacitor element B in the lead frame 13, and the anode lead C and the anode terminal 13a of the tantalum electrolytic capacitor element B are joined to each other by welding. The cathode layer 12b of the capacitor element B and the cathode terminal 13b are bonded via a thermosetting conductive bonding material 15. For example, a silver (Ag) epoxy resin bonding material is used as the conductive bonding material 15 and is cured by heating at a temperature of about 300 ° C. for about 10 minutes.

Further, the tantalum electrolytic capacitor element B to which the lead frame 13 is bonded is placed at a predetermined position, and then the tantalum electrolytic capacitor element B is exposed so that the end portion that becomes the bonded portion with the external electric circuit board is exposed to the outside. A part of the lead frame 13 is coated with an exterior resin 14 made of epoxy, and the exterior resin 14 is cured by heating at 150 to 180 ° C. for about 1 hour. As a result, the polymer crosslinking ratio of the exterior resin 14 is increased, the heat resistance and moisture resistance are improved, and the highly reliable tantalum electrolytic capacitor 11 is obtained. Next, the lead frame 13 is bent downward along the outer shape of the exterior resin 14 so that the anode terminal 13a and the cathode terminal 13b are located on the lower surface of the tantalum electrolytic capacitor 11, thereby constituting a part of the lower surface of the tantalum electrolytic capacitor 11. To do. This facilitates mounting on an external electric circuit board and can be suitable for mass production.
JP 2002-134360 A (page 3-4, FIG. 1)

  In recent years, solders that do not use lead (Pb) have been used as the awareness of global environmental problems has increased. However, the solder containing no Pb has a soldering temperature of 40-50 compared to the conventional solder processing temperature (220-230 ° C.) of Pb (lead) 40% -Sn (tin) 60%. When the soldering is performed at this temperature, the exterior resin 14 is altered by heat and a gap is formed between the lead frame 13 and moisture enters the gap to generate a leakage current or short circuit. It has a problem of causing defects due to.

Therefore, it has been studied to add a filler such as silica (SiO ₂ ) or alumina (Al ₂ O ₃ ) to the exterior resin 14 to impart high heat resistance. In this case, the thermal expansion coefficient of the exterior resin 14 is considered. And the difference from the thermal expansion coefficient of the lead frame 13 is increased, so that a gap is generated between the lead frame 13 and the exterior resin 14 at the temperature when soldering, and moisture enters and the above-mentioned defect occurs. This method is not practical.

Furthermore, the use of a highly heat-resistant resin such as polyimide as the exterior resin 14 has also been studied. In addition to the expensive material, polyimide has a coefficient of thermal expansion that is the coefficient of thermal expansion of the lead frame 13 (7 × 10 ⁻ 60 × 10 ⁻⁶ / ° C., which is more than eight times that of ⁶ / ° C.), so that there is still a problem that a gap is generated between the lead frame 13 and the exterior resin 14, leading to the above-mentioned defect. It was.

  Further, in the conventional tantalum electrolytic capacitor, since the anode lead C is joined to the lead frame 13 by welding, the resistance value of the joint portion is increased, and thus the signal transmission loss of the completed tantalum electrolytic capacitor 11 is increased. As a result, there has been a problem that a signal propagation delay occurs.

  Therefore, the present invention has been completed in view of the above problems, and its purpose is to maintain the airtightness of the tantalum electrolytic capacitor element even when the tantalum electrolytic capacitor is exposed to a high temperature. An object of the present invention is to provide a ceramic container capable of reducing the signal propagation delay and a tantalum electrolytic capacitor using the ceramic container.

  In the ceramic container of the present invention, a rectangular parallelepiped recess is formed at the center of the upper surface, a step is formed between one inner surface and the bottom surface of the recess, and the first conductor layer and the second conductor are formed on the lower surface. A ceramic base provided with conductor layers independently of each other, a notch formed from the top surface to the side surface of the step, a first metallization layer formed on the side surface and bottom surface of the notch, and a bottom surface of the recess A first metallization layer formed on the outer surface of the ceramic base body, and first and second grooves formed on the inner surface with first and second side conductors, respectively. The first metallization layer is electrically connected to the first conductor layer via a first internal wiring and the first side conductor, and the second metallization layer is Second internal wiring and said second side And it is characterized in that it is electrically connected to the second conductive layer through the conductor.

  The ceramic container of the present invention is preferably characterized in that, in the above configuration, the first and second conductor layers are each divided into a plurality of parts.

  In the ceramic container of the present invention, preferably, in the above configuration, the first and second conductor layers are respectively formed on the lower surfaces of the first and second protrusions protruding from the lower surface of the ceramic base. It is characterized by.

  The ceramic container of the present invention is preferably characterized in that a metal frame-like member is brazed around the recess on the upper surface of the ceramic substrate.

  Further, the tantalum electrolytic capacitor of the present invention has one end embedded in the side surface of the ceramic container of the present invention and the sintered body of tantalum powder and the other end electrically connected to the first metallized layer. A tantalum electrolytic capacitor element having an anode lead terminal and a cathode layer deposited on a lower surface of the sintered body and electrically connected to the second metallization layer; and And a lid attached to close the recess.

  According to the ceramic container of the present invention, the rectangular parallelepiped concave portion is formed in the central portion of the upper surface, the step is formed between the inner side surface and the bottom surface of the concave portion, and the first conductor layer and the second conductive layer are formed on the lower surface. A ceramic base provided with two conductor layers independently of each other; a notch formed from the top surface to the side surface of the step; a first metallization layer formed on the side surface and bottom surface of the notch; and a bottom surface of the recess A second metallized layer formed on the outer surface of the ceramic substrate and a first groove and a second groove formed on the inner surface with first and second side conductors, respectively. The first metallization layer is electrically connected to the first conductor layer via the first internal wiring and the first side conductor, and the second metallization layer is connected to the second internal wiring. Second conductor through second side conductor Therefore, the airtightness of the ceramic substrate having the internal wiring is much more reliable than the airtightness of the conventional structure having the exterior resin and the lead frame. Since there is almost no hygroscopicity, moisture does not enter the inside of the ceramic container, so that the tantalum electrolytic capacitor does not malfunction due to corrosion due to moisture, etc., and the substrate is excellent in heat resistance Therefore, since it is a material that can withstand soldering at a high temperature and has a dielectric constant smaller than that of a resin, a ceramic container having good electrical characteristics can be provided.

  In addition, by providing both the first and second conductor layers electrically connected to the anode lead terminal and the cathode layer of the tantalum electrolytic capacitor on the lower surface of the ceramic substrate, an external electric circuit board can be used without using a lead frame or the like. It is possible to easily connect to the surface wiring conductor by surface mounting, and since there is no need to bend the lead frame, the mass productivity is excellent.

  In the ceramic container of the present invention, preferably, in the above configuration, the first and second conductor layers are each divided into a plurality of parts, so that the first and second conductor layers are in contact with the external electric circuit board. Because the area is small and divided, the heat from the molten solder is transferred to the ceramic container via the first and second conductor layers when the ceramic container is soldered to the external electric circuit board. Can be suppressed. As a result, it is possible to effectively suppress the occurrence of thermal stress between the second metallized layer in the ceramic container and the cathode layer on the outer surface of the tantalum electrolytic capacitor element, thereby improving the reliability related to the electrical characteristics of the tantalum electrolytic capacitor. In addition to improving the thermal stress due to the difference in thermal expansion coefficient between the first and second conductor layers and the ceramic substrate, it is possible to effectively suppress the occurrence of cracks and the like in the ceramic substrate. Reliability due to hermeticity of the container can be improved.

  According to the ceramic container of the present invention, preferably, in the above configuration, the first and second conductor layers are formed on the lower surfaces of the first and second protruding portions protruding from the lower surface of the ceramic base. Even if the external electric circuit board is warped, it can be reliably connected to the electrode on the surface of the external electric circuit board, and a ceramic container having good connection strength and reliability can be provided. Furthermore, since the side surface of the protruding portion touches the outside air over the entire circumference, the cooling effect is increased, and distortion due to thermal stress in the ceramic container can be suppressed.

  Further, according to the ceramic container of the present invention, preferably, the metal frame-like member is brazed around the recess on the upper surface of the ceramic base, so that the lid is joined to the upper surface of the ceramic container by welding. The lid can be firmly joined so that no gap is generated, and the airtightness inside the ceramic container can be maintained well. Accordingly, it is possible to effectively prevent moisture and the like from entering the inside of the ceramic container, and thus it is possible to effectively prevent the occurrence of a leakage current or the occurrence of a short circuit. As a result, it is possible to reduce the possibility that the tantalum electrolytic capacitor element housed inside will ignite due to a short circuit and cause a fire.

  In addition, the airtightness of the tantalum electrolytic capacitor element can be effectively prevented from being deteriorated due to corrosion due to moisture and the like, compared with the airtightness of the structure having the conventional exterior resin and the lead frame. A highly reliable ceramic container capable of maintaining the electrical characteristics of the capacitor element well over a long period of time can be obtained.

  Moreover, the tantalum electrolytic capacitor of the present invention has one end embedded in the side surface of the ceramic container of the present invention and the sintered body of tantalum powder, and the other end electrically connected to the first metallized layer. A tantalum electrolytic capacitor element having an anode lead terminal and a cathode layer deposited on the lower surface of the sintered body and electrically connected to the second metallization layer, and so as to close the recess on the upper surface of the ceramic substrate Since the ceramic container of the present invention is used, it is highly reliable due to hermeticity, and is manufactured by a multi-cavity method using a known ceramic green sheet lamination method. Because it can, it will be excellent in mass productivity. Furthermore, since the electrical resistance can be reduced by electrically connecting the anode lead terminal to the first metallized layer, the electrical resistance of the tantalum electrolytic capacitor can be reduced, and the transmission loss of the tantalum electrolytic capacitor can be reduced. Can be reduced.

  The ceramic container of the present invention will be described in detail below. 1A is a plan view showing an example of an embodiment of the ceramic container of the present invention, and FIG. 1B is a cross-sectional view of FIG. 2 is a perspective view of an example of an embodiment of the ceramic container of the present invention as viewed from below, and FIG. 3 is a perspective view of another example of an embodiment of the ceramic container of the present invention as viewed from below. is there. In these figures, 1 is a ceramic substrate, 1a is a recess, 1b is a second metallized layer, 1c-A is a step, 2 is a notch, 2a is a first metallized layer, 3a is a first internal wiring, 3b Is the second internal wiring, 4a is the first conductor layer, 4b is the second conductor layer, 4c is the first side conductor, 4d is the second side conductor, and 5a and 5b are the first and second protrusions , 6 is a lid, A is a ceramic container, B is a tantalum electrolytic tantalum electrolytic capacitor element, C is an anode lead terminal, D is a cathode layer, and E is a conductive bonding material.

  In the ceramic container A of the present invention, a rectangular parallelepiped recess 1a is formed at the center of the upper surface of the ceramic substrate 1, and a step 1c-A is formed between one inner side surface of the recess 1a and the bottom surface of the recess 1a. For example, as shown in FIG. 1, a first conductor layer 4a is formed at a position immediately below the step 1c-A on the lower surface, and immediately below the inner surface facing the one inner surface on which the step 1c-A is formed. The second conductor layer 4b is provided in each of the regions.

  Further, a notch 2 is formed from the upper surface to the side surface of the step 1c-A, the first metallized layer 2a is formed on the side surface and the bottom surface of the inner surface of the notch 2, and the second surface is formed on the bottom surface of the recess 1a. The metallized layer 1b is formed. Further, the first internal wiring 3 a that is electrically connected to the first metallized layer 2 a and penetrates the inside of the ceramic base 1 and the first conductor layer 4 a on the lower surface of the ceramic base 1 are electrically connected. A first side conductor 4 c (so-called castoration conductor) is formed in a first groove formed on the outer surface of the ceramic substrate 1. Further, the second internal wiring 3 b that is electrically connected to the second metallized layer 1 b and penetrates the inside of the ceramic base 1 and the second conductor layer 4 b on the lower surface of the ceramic base 1 are electrically connected. A second side conductor 4d (castoration conductor) is formed in a second groove formed on the outer surface of the ceramic substrate 1.

Such a ceramic substrate 1 is made of ceramics such as an alumina sintered body and is produced, for example, as follows. That is, when the ceramic substrate 1 is made of an alumina sintered body, an organic material suitable for raw material powders such as aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), magnesium oxide (MgO), calcium oxide (CaO), etc. A binder, a solvent, etc. are added and mixed to form a slurry. This slurry is formed into a green sheet by a doctor blade method or a calender roll method and cut into a required size. Next, in a plurality of green sheets selected from them, suitable for forming grooves for forming the recesses 1a, steps 1c-A, notches 2, first and second side conductors 4c, 4d. Punching is performed.

  Then, a metal paste mainly composed of a metal powder such as tungsten (W) is printed and applied to these green sheets, and the first and second metallized layers 2a and 1b, and the first and second internal wirings 3a and 3b. The first and second conductor layers 4a and 4b are formed, then the green sheets on which these conductor layers are formed are laminated, and the first and second grooves are formed in the first and second grooves on the outer surface. The ceramic substrate 1 is manufactured by applying a metal paste for forming the side conductors 4c and 4d and finally firing at a temperature of about 1600 ° C.

  Further, the exposed surface of these conductor layers formed on the ceramic substrate 1 thus produced has a metal excellent in corrosion resistance and wettability with solder, specifically having a thickness of 1 to 12 μm. A nickel (Ni) layer and a gold (Au) layer having a thickness of 0.3 to 5 μm are preferably sequentially deposited by a plating method or the like. Thereby, in the first and second conductor layers 4a and 4b, the wettability with the solder is improved, and the bonding strength with the electrode (not shown) on the external electric circuit board becomes stronger.

  If the thickness of the Ni layer is less than 1 μm, it becomes difficult to prevent the oxidative corrosion of each conductor layer made of the metallized layer, and the bonding strength to the external electric circuit board is likely to deteriorate. On the other hand, if the thickness of the Ni layer exceeds 12 μm, it takes a long time to form the plating, so that the mass productivity is likely to be lowered and the electric resistance is likely to be increased.

  In addition, if the thickness of the Au layer is less than 0.3 μm, it is difficult to form an Au layer having a uniform thickness, and a portion where the Au layer is extremely thin or a portion where the Au layer is not formed is generated. Therefore, the effect of preventing oxidative corrosion and the wettability with solder are likely to decrease. On the other hand, if the thickness of the Au layer exceeds 5 μm, it takes a long time to form the plating, and the mass productivity tends to decrease.

  In the ceramic substrate 1, a notch 2 is formed from the top surface to the side surface of the step 1c-A, and a first metallized layer 2a is formed on the bottom surface and the side surface of the notch 2. Further, the first metallized layer 2a is also coated with Ni plating or Au plating on the surface as described above.

  On the lower surface of the ceramic substrate 1, first and second conductor layers 4a and 4b are connected to the first and second side conductors 4c and 4d and the first and second internal wirings 3a and 3b. Each of the second metallized layers 2a and 1b is formed in electrical connection. These first and second conductor layers 4a and 4b are joined to a wiring conductor on the surface of an external electric circuit board (not shown) via solder.

  According to the ceramic container A of the present invention configured as described above, the hermeticity of the ceramic substrate 1 having the first and second internal wirings 3a and 3b is compared with that of the conventional one made of the exterior resin and the lead frame. In addition, since the ceramic substrate 1 has almost no hygroscopicity, moisture does not enter the ceramic container A, and therefore the tantalum electrolytic capacitor F malfunctions due to corrosion due to moisture. It is possible to maintain good electrical characteristics over a long period of time.

  Further, by providing both the first and second conductor layers 4a and 4b electrically connected to the anode lead terminal C and the cathode layer D of the tantalum electrolytic capacitor F on the lower surface of the ceramic substrate 1, a lead frame or the like is provided. Without being used, it can be easily connected to the wiring conductor on the surface of the external electric circuit board by surface mounting, and there is no need to bend the lead frame, so that it is excellent in mass productivity.

  In the ceramic container A of the present invention, the first and second conductor layers 4a and 4b are preferably divided into a plurality of parts. Since the first and second conductor layers 4a and 4b are divided into a plurality of parts, the area of each of the divided conductor layers is reduced, and the contact area between these and the external electric circuit board is reduced. It is possible to suppress the heat of the solder melted when soldering A to the electrode of the external electric circuit board or the like from being transmitted to the ceramic container A via the first and second conductor layers 4a and 4b. As a result, it is possible to effectively suppress the generation of thermal stress between the second metallized layer 1b in the ceramic container A and the cathode layer D on the outer surface of the tantalum electrolytic tantalum electrolytic capacitor element B. Since the thermal stress due to the difference in thermal expansion coefficient between the conductor layers 4a and 4b and the ceramic substrate 1 can be reduced and the occurrence of cracks and the like in the ceramic substrate 1 can be effectively suppressed, the airtightness of the ceramic container A can be reduced. Therefore, the reliability of the tantalum electrolytic capacitor F can be greatly improved.

  In the ceramic container A of the present invention, as shown in FIG. 3, the first and second conductor layers 4 a and 4 b have first and second protrusions 5 a and 5 b provided on the lower surface of the ceramic substrate 1. More preferably, it is formed on the lower surface of the. As a result, even if the external electric circuit board is warped, it can be more reliably connected to the electrode on the surface of the external electric circuit board, and the connection strength and reliability are improved. Further, since the side surfaces of the first and second projecting portions 5a and 5b are in contact with the outside air over the entire circumference, the cooling effect is increased, and the solder melted when the ceramic container A is soldered to the electrode of the external electric circuit board or the like. Is transferred to the recess 1a of the ceramic container A, and thermal stress is generated between the tantalum electrolytic capacitor element B housed in the recess 1a and the second metallized layer 1b formed on the bottom surface of the recess 1a of the ceramic container A. Generation | occurrence | production can be suppressed effectively. As a result, the reliability relating to the electrical characteristics of the tantalum electrolytic capacitor F can be improved.

  The first and second conductor layers 4a and 4b formed on the lower surfaces of the first and second projecting portions 5a and 5b are, for example, portions located immediately below the step 1c-A on the lower surface of the ceramic base 1. In the case where the second protrusion 5b is formed at a portion immediately below the inner surface opposite to the inner surface on which the first protrusion 5a and the step 1c-A are formed, the first protrusion 5a The first conductor layer 4a is formed on the lower surface of the second conductor layer, and the second conductor layer 4b is formed on the lower surface of the second protrusion 5b.

  The first and second conductor layers 4a and 4b formed on the lower surfaces of the first and second protrusions 5a and 5b are formed on the entire lower surfaces of the first and second protrusions 5a and 5b. Although it may be formed, as shown in FIG. 3, it may be divided into a plurality of parts on the lower surface of each of the first and second protrusions 5a, 5b. Thereby, it is possible to effectively suppress the generation of thermal stress between the second metallized layer 1b and the cathode layer D of the tantalum electrolytic capacitor element B as described above, and the first and second conductor layers 4a, Thermal stress due to the difference in thermal expansion coefficient between 4b and the ceramic substrate 1 can be relaxed, and the occurrence of breakage such as cracks in the ceramic substrate 1 can be effectively suppressed.

  In the ceramic container A of the present invention, preferably, a metal frame-like member 7 is brazed so as to surround the recess 1a around the recess 1a on the upper surface of the ceramic substrate 1, as shown in FIG. Is good. 6 shows another example of the embodiment of the ceramic container A of the present invention, where (a) is a plan view of the ceramic container A and (b) is a cross-sectional view of the ceramic container A. FIG. Portions common to FIGS. 1 to 4 other than the frame member 7 are denoted by the same reference numerals.

  The frame-like member 7 is made of a metal such as an iron (Fe) -Ni-cobalt (Co) alloy or aluminum (Al), and has a recess 1a on the upper surface of the ceramic substrate 1 via silver (Ag) brazing, Al brazing, or the like. Brazed around. A metallized layer made of W or the like is formed in advance on the surface of the ceramic substrate 1 where the frame-like member 7 is brazed in the same manner as the first and second conductor layers 4a, 4b, etc. Ni or the like is preferably plated. By performing the plating of Ni or the like, the wettability with the brazing material of the upper surface of the ceramic substrate 1 is improved, and the bonding strength between the metallized layer on the upper surface of the ceramic substrate 1 and the frame member 7 is further strengthened. It will be something.

  Then, a metal lid 6 such as Fe—Ni—Co alloy or Al alloy is joined to the frame-like member 7 by seam welding or the like, and firmly attached so as to close the recess 1 a on the upper surface of the ceramic substrate 1. Thus, the concave portion 1a of the ceramic substrate 1 can be reliably hermetically sealed. Accordingly, it is possible to more effectively prevent moisture, oxygen, and the like from entering the concave portion 1a from between the ceramic base 1 and the lid 6 from the outside, so that a leakage current flows into the tantalum electrolytic capacitor element B enclosed inside. It is possible to effectively prevent the occurrence of defects and the occurrence of defects due to short circuits. As a result, it is possible to reduce the possibility that the tantalum electrolytic capacitor element B housed inside will ignite and cause a fire due to a short circuit.

  In addition, since it is possible to effectively prevent the tantalum electrolytic capacitor element B from being deteriorated due to corrosion due to moisture, etc., a highly reliable ceramic container A capable of maintaining the electrical characteristics of the tantalum electrolytic capacitor element B satisfactorily over a long period of time is provided. it can.

  Next, the tantalum electrolytic capacitor F of the present invention will be described in detail below. FIG. 4 is a cross-sectional view showing an example of an embodiment of the tantalum electrolytic capacitor F of the present invention, where B is a tantalum electrolytic capacitor element, C is an anode lead terminal, D is a cathode layer, and E is a conductive bonding material.

  The tantalum electrolytic capacitor F of the present invention includes an anode lead terminal C formed by embedding one end portion in the sintered body from the side surface of the sintered body of tantalum powder, and a cathode layer D formed on the outer periphery of the sintered body. The tantalum electrolytic capacitor element B having The anode lead terminal C is joined to the notch 2 at the other end via the conductive bonding material E, and the notch 2 on the step 1c-A is covered with the conductive bonding material E. The electrical resistance of the connection portion between the anode lead terminal C and the first metallized layer 2a can be reduced, and the anode lead terminal C can be firmly joined to the first metallized layer 2a of the notch 2. Furthermore, since the cathode layer D is electrically bonded to the second metallized layer 1b over a wide area by the conductive bonding material E, the electrical resistance of the connecting portion between the cathode layer D and the second metallized layer 1b is also small. Since the cathode layer D can be firmly bonded to the second metallized layer 1b, the tantalum electrolytic capacitor F with high electrical connection reliability and low electrical resistance can be obtained.

  As a result, the tantalum electrolytic capacitor F of the present invention has high airtight reliability due to the use of the ceramic container A of the present invention, and can be produced by a multi-cavity method using a known ceramic green sheet lamination method. It will be excellent. Further, since the tantalum electrolytic capacitor F can reduce the electrical resistance between the anode lead terminal C and the first metallized layer 2a and the cathode layer D and the second metallized layer 1b, the electrical resistance of the tantalum electrolytic capacitor F can be reduced. The loss of the signal transmitted through the tantalum electrolytic capacitor F can be reduced.

  The lid body 6 is made of ceramics such as an alumina sintered body, and a conventionally known metallized layer is formed on the lower surface of the lid body 6 to be joined to the ceramic base body 1. A conventionally well-known metallized layer is also formed around the concave portion 1a, and these metallized layers are bonded to each other with a brazing material such as solder and sealed to be airtightly attached to the upper surface of the ceramic substrate 1. .

  In addition, when a metal frame member 7 is brazed around the recess 1a on the upper surface of the ceramic substrate 1 as shown in FIG. 6, a lid is placed on the upper surface of the frame member 7 as shown in FIG. The body 6 is placed, and the outer periphery of the lid body 6 and the frame-like member 7 is welded and joined by a welding method such as a seam welding method so that the lid body 6 is firmly and airtightly attached to the upper surface of the ceramic substrate 1. Worn.

  More preferably, an inert gas such as nitrogen or argon is sealed inside the ceramic container A, and the tantalum electrolytic capacitor element B is reliably prevented from reacting with the internal gas of the ceramic container A to be corroded. The electrolytic capacitor element B can be operated extremely well over a long period of time.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the present invention, the case where the material of the ceramic base 1 of the ceramic container A is an alumina sintered body has been described, but the ceramic base 1 may be made of other ceramics such as an aluminum nitride (AlN) sintered body or glass ceramics. Good. In the case of an AlN sintered body, heat during operation can be efficiently dissipated to the outside, so that the tantalum electrolytic capacitor F that can maintain the electrical characteristics of the tantalum electrolytic capacitor F for a longer period can be obtained. .

  The tantalum electrolytic capacitor of the present invention can be used in a wide range of fields including communication equipment such as mobile phones, AV equipment such as digital cameras, computer equipment such as personal computers, and automobile equipment such as airbags and antilock brakes. In particular, it can be suitably used in applications that require extremely high reliability such as in-vehicle use, aircraft use, and satellite use.

An example of embodiment of the ceramic container of this invention is shown, (a) is a top view of a ceramic container, (b) is sectional drawing of (a). It is the perspective view of the ceramic container seen from the lower surface side which shows an example of embodiment of the ceramic container of this invention. It is the perspective view of the ceramic container seen from the lower surface side which shows the other example of embodiment of the ceramic container of this invention. It is sectional drawing which shows an example of embodiment of the tantalum electrolytic capacitor of this invention. It is sectional drawing which shows the example of the conventional tantalum electrolytic capacitor. The other example of embodiment of the ceramic container of this invention is shown, (a) is a top view of a ceramic container, (b) is sectional drawing of (a). It is sectional drawing which shows the other example of embodiment of the tantalum electrolytic capacitor of this invention.

Explanation of symbols

1: Ceramic substrate 1a: Concave part 1b: Second metallized layer 1c-A: Step 2: Notch 2a: First metallized layer 3a: First internal wiring 3b: Second internal wiring 4a: First conductor Layer 4b: Second conductor layer 4c: First side conductor 4d: Second side conductor 5a: First protrusion 5b: Second protrusion 6: Lid 7: Frame member A: Ceramic container B : Tantalum electrolytic capacitor element C: Anode lead terminal D: Cathode layer E: Conductive bonding material F: Tantalum electrolytic capacitor

Claims (5)

A rectangular parallelepiped recess is formed at the center of the upper surface, a step is formed between one inner side surface and the bottom surface of the recess, and the first conductor layer and the second conductor layer are independently formed on the lower surface. A ceramic base provided; a notch formed from the top surface to the side surface of the step; a first metallization layer formed on the side surface and bottom surface of the notch; and a second metal layer formed on the bottom surface of the recess. A metallized layer, and first and second grooves formed on the outer surface of the ceramic base body in the vertical direction and having first and second side conductors formed on the inner surface, respectively, The metallization layer is electrically connected to the first conductor layer via a first internal wiring and the first side conductor, and the second metallization layer is connected to the second internal wiring and the first conductor. Said second conductor through two side conductors Ceramic container, characterized in that it is electrically connected to the. 2. The ceramic container according to claim 1, wherein each of the first and second conductor layers is divided into a plurality of parts. 3. The ceramic container according to claim 1, wherein the first and second conductor layers are respectively formed on the lower surfaces of the first and second protruding portions protruding from the lower surface of the ceramic base. . The ceramic container according to any one of claims 1 to 3, wherein a metal frame-like member is brazed around the recess on the upper surface of the ceramic substrate. 5. The ceramic container according to claim 1 and a tantalum powder sintered body having one end embedded in a side surface and the other end electrically connected to the first metallized layer. A tantalum electrolytic capacitor element having an anode lead terminal and a cathode layer deposited on the lower surface of the sintered body and electrically connected to the second metallization layer; and the recess on the upper surface of the ceramic substrate. A tantalum electrolytic capacitor, comprising: a lid attached so as to close the capacitor.

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