TWI431650B - Manufacturing method of solid electrolytic capacitor and solid electrolytic capacitor thereof - Google Patents

Description

Method for manufacturing solid electrolytic capacitor and solid electrolytic capacitor thereof

The present invention relates to a method of fabricating a capacitor and a capacitor thereof, and more particularly to a method of fabricating a solid electrolytic capacitor and a solid electrolytic capacitor thereof.

According to the trend, electronic devices have rapidly developed toward small size, light weight and portability, so the demand for small and thin electronic components has continued to increase. In particular, electronic components used in electronic devices such as communications and personal computers, such as passive components such as capacitors, must meet the requirements of small size and good electrical characteristics.

Capacitors are classified according to the type of electrolyte, and there are two types of liquid electrolytic capacitors and solid electrolytic capacitors. Among them, the life of the former is determined by the time when the electrolyte is dry, while the latter is due to the use of solid electrolyte, so there is no electrolyte dryness and long life.

The conventional surface-adhesive tantalum solid-state capacitive element structure has a capacitor element body, the anode of the capacitor element body is provided with an anode element made of ruthenium metal powder, which is a valve action metal; and the exterior of the anode element is coated with a dielectric oxide film; The external portion of the dielectric oxide film is sequentially coated with a solid electrolytic layer, a carbon layer conductor, a cathode conductor layer, and the like. In the conventional manufacturing method, the anode element is made of a base metal powder having a relatively high technical threshold. For example, in order to increase the capacitance, it is necessary to use a small particle size of the base metal powder to increase the surface area thereof. The metal powder is subjected to a high-temperature sintering step to form a sintered body. However, as the particle size of the base metal powder is smaller, the production becomes more difficult and the cost is increased. Furthermore, the small particle size of the base metal powder also makes the cathode agent difficult to infiltrate, and the high-temperature sintering step in the process also makes The overall process is more complicated.

The main object of the present invention is to provide a method for manufacturing a solid electrolytic capacitor and a solid electrolytic capacitor thereof, which can replace the tantalum powder with aluminum powder to simplify the process complexity, such as reducing the process temperature, etc., so that Reduce the cost of the effect.

The invention provides a method for fabricating a solid electrolytic capacitor, comprising the steps of: forming an aluminum anode; performing a chemical forming step to form a dielectric layer on the surface of the aluminum anode; forming a conductive layer on the dielectric layer The aluminum anode and the conductive layer are respectively connected to an anode electrode and a cathode electrode; and a packaging step is performed.

The present invention further provides a solid electrolytic capacitor having an aluminum anode, a dielectric layer formed on a surface of the aluminum anode, a conductive layer disposed on the dielectric layer, and a pair of electrode terminals including An anode electrode connected to the aluminum anode and a cathode electrode connected to the conductive layer.

Therefore, the process of the aluminum powder itself is greatly simplified by the characteristics of the aluminum powder itself. For example, the aluminum powder can form an anode having good structural strength without high-temperature sintering, thereby effectively reducing process complexity and cost; further, the aluminum powder can be utilized first. The pretreatment has a high specific surface area on the surface, so that the characteristics of the fabricated capacitor can be improved.

The invention provides a method for manufacturing a solid electrolytic capacitor, which uses aluminum (Al) powder instead of tantalum (Ta) powder to solve the problems caused by the tantalum powder in the manufacturing process of the capacitor.

The method for fabricating the solid electrolytic capacitor of the present invention can be applied to a solid-state electrolytic capacitor of a wafer type or a sheet type (or a film type). For the wafer type solid electrolytic capacitor, the manufacturing method of the solid electrolytic capacitor of the present invention includes at least the following steps:

Step 1: Form an aluminum anode. First, an aluminum powder is supplied, and then a cold pressing step is performed to press the aluminum powder into an aluminum ingot to form the aluminum anode 11 (shown in Fig. 1). In this embodiment, a binder may be added to the aluminum powder, such as camphor, stearic acid, polyvinyl alcohol, naphthalene, etc., and the binder is added in an amount of 3 to 5 wt%; and after being sufficiently mixed, by The cold pressing step is performed by a stamper, and the aluminum powder is press-formed into a rectangular parallelepiped aluminum ingot. The load at cold pressing may be 3 to 15 MN (Mega Newton)/m ² , so that the aluminum ingot after cold pressing has a certain bulk density.

It is worth noting that due to the physical properties of the alumina on the surface of the aluminum powder, it can be destroyed by the process pressure in the aforementioned cold pressing step, so that aluminum powder is formed to form an aluminum ingot having strength and aluminum is formed. The powders are connected to each other and electrically connected. In other words, the present invention can produce an aluminum ingot having electrical characteristics without introducing a high-temperature sintering step, and the pressed aluminum ingot can be applied as the aluminum anode 11 of the capacitor.

Furthermore, in order to improve the characteristics of the solid electrolytic capacitor having a large capacitance and a small leakage current, the aluminum powder of the present invention can be aluminum powder by an etching method before the aforementioned cold pressing step (that is, after the step of providing aluminum powder). The surface of the surface forms a sponge-like uneven surface, for example, immersing the aluminum powder in an acidic etching solution to form an uneven surface on the surface of the aluminum powder to improve The specific surface area of the aluminum powder allows the pressed aluminum ingot to be used to provide better capacitance characteristics.

On the other hand, in the cold pressing step described above, it is further included that an extraction electrode 111 is interposed in the aluminum powder, and the extraction electrode 111 is pressed and synthesized together with the aluminum powder. The extraction electrode 111 can be a wire or an aluminum wire. In the specific embodiment, an aluminum wire having a thickness of about 20 μm is used as the extraction electrode 111. Since the thickness of the aluminum wire is thinner than that of the wire, the aluminum is used. The wire can further reduce the size of the capacitor element, but the invention is not limited thereto, and the extraction electrode 111 can select an appropriate electrode material according to the actual application.

Step 2: A chemical forming step is performed to form a dielectric layer 12 on the surface of the aluminum anode 11 (as shown in FIG. 1). In this step, the pressed aluminum ingot is subjected to a chemical conversion treatment, and an oxidized coating film (i.e., an insulating alumina film) is formed on the surface of the aluminum anode 11 to form a dielectric layer 12. In the above-described chemical conversion reaction, the thickness of the dielectric layer 12 can be controlled according to different chemical formation voltages and chemical conversion liquids. In the present embodiment, the dielectric layer 12 is formed by a chemical solution of ammonium adipate or phosphoric acid or a mixture of the two. .

Step 3: Form a conductive layer on the dielectric layer 12. Referring to FIG. 1 , in this embodiment, the conductive layer may be made of a conductive polymer such as poly 3,4-ethylenedioxythiophene (PEDOT), polypyrrole, polythiophen, and carbon (or graphite). , a silver glue or the like; specifically, a poly 3,4-ethylene dioxythiophene (PEDOT) material can form the electrolyte layer 13, and the carbon rubber layer 14, the silver glue layer 15 and the like can be formed to form the A conductive layer to serve as a cathode for the capacitor.

Step 4: connecting the aluminum anode 11 and the conductive layer (ie, the electrolyte layer 13, the carbon glue layer 14 and the silver glue layer 15) to a pair Electrode terminals, such as an anode electrode 16A and a cathode electrode 16B. Specifically, the anode electrode 16A and the cathode electrode 16B may be respectively connected to the extraction electrode 111 and the silver paste layer 15 by a conductive bonding agent or other connection method.

Finally, a packaging step is performed, for example, the capacitor is covered with a coating material such as a resin, and the anode electrode 16A and the cathode electrode 16B are exposed, and the package 17 is formed by performing steps of curing, aging, etc., thereby completing the present invention. Solid electrolytic capacitors.

With reference to FIG. 2, for a thin-film solid electrolytic capacitor, the manufacturing method of the solid electrolytic capacitor of the present invention includes at least the following steps:

Step 1: Form an aluminum anode. First, a substrate 10 is provided; an aluminum powder-containing glue is applied onto the substrate 10, and the aluminum-containing glue is cured to form the aluminum anode 11'. In the present embodiment, a commercially available aluminum paste is applied to the substrate 10 by printing, spraying, or the like, and after it is cured, the aluminum anode 11' of the capacitor can be formed. The aluminum powder contained in the glue may also be pretreated to have an uneven surface of irregularities to form aluminum powder having a high specific surface area.

In addition, in the same step as the foregoing embodiment, the step of applying the aluminum powder-containing glue to the substrate 10 further includes inserting an extraction electrode (not shown) into the aluminum-containing glue, for example, about the thickness. It is a 20 μm aluminum wire to facilitate the subsequent process of taking out the anode.

Step 2: A chemical forming step is performed to form a dielectric layer 12' on the surface of the aluminum anode 11' (as shown in FIG. 2). In this step, the substrate 10 and the aluminum anode 11' are subjected to a chemical conversion treatment, that is, anodization, so that an oxidized coating film (ie, an insulating aluminum oxide film) is formed on the surface of the aluminum anode 11'. To form a dielectric layer 12'. The above formation The reaction can control the thickness of the dielectric layer 12' according to different chemical formation voltages and chemical conversion liquids. In this embodiment, the dielectric layer 12' is formed by a chemical solution of ammonium adipate or phosphoric acid or a mixture of the two. .

Step 3: Form a conductive layer on the dielectric layer 12'. 2, in this embodiment, the conductive layer may be made of a conductive polymer such as poly 3,4-ethylenedioxythiophene (PEDOT), polypyrrole, polythiophen, and carbon (or graphite). And silver colloid, etc.; specifically, the poly 3,4-ethylenedioxythiophene (PEDOT) material can form the electrolyte layer 13', and the carbon glue layer 14', the silver glue layer 15', etc. can be formed. The conductive layer acts as a cathode for the capacitor.

Next, in the same manner as the foregoing embodiment, the aluminum anode 11' and the conductive layer (ie, the electrolyte layer 13', the combination of the carbon glue layer 14' and the silver paste layer 15') are respectively connected to the anode electrode and the cathode electrode (Fig. A sheet-type solid electrolytic capacitor can be produced by covering a capacitor with a coating material such as a resin.

Therefore, the present invention can replace the tantalum powder with aluminum powder, so the process of the capacitor can be greatly simplified, for example, steps such as high-temperature sintering are not required; in addition, the aluminum powder can be pretreated to have a high specific surface area, thereby improving the preparation. The characteristics of the capacitor.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the equivalents of the present invention are intended to be included within the scope of the present invention.

10‧‧‧Substrate

11, 11'‧‧‧Aluminum anode

111‧‧‧Extraction electrode

12, 12'‧‧‧ dielectric layer

13, 13'‧‧‧ electrolyte layer

14, 14'‧‧‧carbon layer

15, 15'‧‧‧ silver glue layer

16A‧‧‧Anode electrode

16B‧‧‧Cathode electrode

17‧‧‧Package

1 is a schematic view showing a solid electrolytic capacitor of a first embodiment of the present invention; Figure.

Fig. 2 is a schematic view showing a solid electrolytic capacitor of a second embodiment of the present invention.

11. . . Aluminum anode

111. . . Lead electrode

12. . . Dielectric layer

13. . . Electrolyte layer

14. . . Carbon layer

15. . . Silver layer

16A. . . Anode electrode

16B. . . Cathode electrode

17. . . Package

Claims (9)

A method for manufacturing a solid electrolytic capacitor, comprising the steps of: forming an aluminum anode, further comprising the steps of: providing an aluminum powder; and performing a pressing step by pressing the aluminum powder into an aluminum ingot to form the aluminum powder. An aluminum anode; a chemical forming step of forming a dielectric layer on the surface of the aluminum anode; forming a conductive layer on the dielectric layer; and connecting the aluminum anode and the conductive layer to an anode electrode and a cathode electrode; and performing a packaging step. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein in the step of performing a pressing, the method further comprises inserting an extraction electrode into the aluminum powder, and the extraction electrode is combined with the aluminum powder. type. The method for producing a solid electrolytic capacitor according to claim 2, wherein after the step of providing the aluminum powder, the step of forming the surface of the aluminum powder into a sponge-like uneven surface by an etching method is further included. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein in the step of molding an aluminum anode, the method further comprises the steps of: providing a substrate; and coating the aluminum powder-containing glue on the substrate And make the aluminum-containing glue solid Formed to form the aluminum anode described. The method for manufacturing a solid electrolytic capacitor according to claim 4, wherein the step of applying the aluminum powder-containing glue to the substrate further comprises inserting an extraction electrode into the aluminum-containing glue. . The method for manufacturing a solid electrolytic capacitor according to claim 4, wherein in the step of applying the aluminum powder-containing glue to the substrate, the aluminum-containing glue is applied to the substrate by a printing method. on. A solid electrolytic capacitor comprising: an aluminum anode, which is an aluminum ingot, which is formed by press molding of aluminum powder; a dielectric layer formed on the surface of the aluminum anode; a conductive layer on the dielectric layer; and a pair of electrode terminals including an anode electrode connected to the aluminum anode and a cathode electrode connected to the conductive layer. The solid electrolytic capacitor according to claim 7, wherein the aluminum anode is formed by coating an aluminum paste on a substrate. The solid electrolytic capacitor according to claim 8, wherein the aluminum powder has a sponge-like uneven surface.