JP2009272476A - Chip resistor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wire bonding connection type chip resistor which has sufficient strength and superior heat dissipation properties. <P>SOLUTION: The chip resistor A having a laminar resistance element 1 and includes an insulating base 3 bonded to one surface of the resistance element 1 to support the whole resistance element 1, and a projection film 4 covering part of the resistance element 1 from above the base 3 so as to expose both edges 1A of the resistance element 1 as electrode pad parts for wire bonding. The resistance element 1 has a cut 1a formed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a chip resistor and a manufacturing method thereof.

  As a conventional chip resistor, there is one disclosed in Patent Document 1. The chip resistor disclosed in this document is configured by providing a pair of electrodes on one side of a resistor. The pair of electrodes are directly bonded to one side of the resistor in a state of being insulated from each other, and are applied as terminals for surface mounting. An overcoat layer is formed on one surface of the resistor that is opposite to the surface to which the electrodes are bonded so as to protect the resistor. In such a chip resistor, when a metal plate made of an alloy having a small resistance temperature coefficient (TCR) is used as a resistor, an extremely low resistance of several mΩ can be realized in addition to a reduction in TCR. In order to realize a resistance higher than an ultra-low resistance of several mΩ, for example, a resistance of several tens to several hundreds mΩ, a part of the resistor is partially thinned by laser trimming or etching. Try to remove.

  However, in the above conventional chip resistor, the resistor itself is made of a relatively thin metal plate and does not have a strong shape for joining the electrodes, and the resistor is in the air via the electrodes when mounted on the surface. Therefore, the whole chip resistor may be insufficient in strength. In addition, when energized, if the resistor generates heat, the heat tends to be trapped, resulting in poor heat dissipation.

JP 2007-49207 A

  The present invention has been conceived under the circumstances described above, and an object thereof is to provide a wire bonding connection type chip resistor having sufficient strength and excellent heat dissipation. . Another object of the present invention is to provide a chip resistor manufacturing method suitable for mass production of such chip resistors.

  The chip resistor provided by the first aspect of the present invention is a chip resistor provided with a layered resistor, and has an insulating property bonded to one side of the resistor so as to support the entire resistor. And a protective film that covers a part of the resistor from above the substrate so that both edge portions of the resistor are exposed as electrode pads for wire bonding. It is characterized by.

  In a preferred embodiment of the present invention, the resistor is formed with a cut portion.

  In a preferred embodiment of the present invention, the resistor and the base material are bonded via an insulating adhesive layer.

  The method of manufacturing a chip resistor provided by the second aspect of the present invention includes a step of bonding a metal plate serving as a material of a resistor and an insulating substrate serving as a base material, and etching the metal plate. Forming a protective film on the substrate so that a part of the metal plate is exposed as an electrode pad portion for wire bonding and covering the remainder, the metal plate, the substrate, and the protection And a step of dividing the integrated film into chips.

  In a preferred embodiment of the present invention, when the metal plate is etched, a cut portion is formed in the metal plate.

  According to such a configuration, the resistor can be provided with sufficient strength by supporting it with an insulating reinforcing material, and a wire bonding connection type chip resistor excellent in heat dissipation can be provided through the reinforcing material. Can be realized. In addition, a chip resistor manufacturing method suitable for mass production of such chip resistors can be realized.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 and 2 show an embodiment of a chip resistor according to the present invention, and FIGS. 3 and 4 show an example of a manufacturing method thereof. As shown in FIGS. 1 and 2, the chip resistor A of the present embodiment is configured to include a resistor 1, an adhesive layer 2, a base material 3, and a protective film 4. The chip resistor A is electrically connected to a printed wiring board (not shown) via a wire W, and is configured to have a low resistance of about several tens mΩ to several hundreds mΩ.

  The resistor 1 is made of a metal plate having a relatively low temperature resistance coefficient (TCR), such as a Ni—Cr alloy, a Ni—Cu alloy, a Fe—Cr alloy, or a Cu—Mn alloy, and has a thickness of 10 to 100 μm. It has a thickness of about. The resistor 1 has a cut portion 1a that is removed by etching to adjust to a desired resistance value. Both edge portions 1A where the cut portions 1a are formed are used as electrode pad portions for connecting the wires W by bonding.

  The adhesive layer 2 is provided between the resistor 1 and the substrate 3 and plays a role of firmly bonding the resistor 1 and the substrate 3. Such an adhesive layer 2 has a thickness of about 60 to 100 μm, and is made of, for example, a prepreg (insulating adhesive film) obtained by impregnating a glass fiber with an adhesive resin as described later.

  The substrate 3 is directly fixed to a mounting surface such as a printed wiring board, and is bonded to one surface of the resistor 1 via the adhesive layer 2. The base material 3 is made of an insulating material such as alumina or glass epoxy resin, and plays a role of increasing the strength of the chip resistor A and also efficiently dissipating heat generated in the resistor 1 when energized. Have. Such a base material 3 has a thickness of about 200 to 400 μm.

  The protective film 4 is provided so as to cover the center portion of the resistor 1 from above the base material 3 so as to expose both edge portions 1A, and is coated with, for example, an epoxy resin-based insulating material having electrical insulation properties. It is formed by that.

Next, an example of a manufacturing method of the chip resistor A will be described with reference to FIGS.

  First, as shown in FIG. 3A, a state in which a prepreg 20 serving as an adhesive layer 2 is sandwiched between a metal plate 10 serving as a material of the resistor 1 and an insulating substrate 30 serving as a base material 3. The metal plate 10, the prepreg 20, and the substrate 30 are joined by a high-pressure vacuum press. Such metal plate 10, prepreg 20, and substrate 30 have a size that allows a plurality of chip resistors A to be taken, and correspond to the thicknesses of resistor 1, adhesive layer 2, and substrate 3. .

  Next, as shown in FIG. 3B, the plurality of resistors 1 are formed by performing an etching process on the metal plate 10. The resistor 1 formed in this way has a form having cut portions 1a at both edge portions 1A, and is located at each location to be a chip and spaced apart from each other.

  Next, as shown in FIG. 4A, an insulating film 40 is applied in a stripe shape from above the substrate 10 so as to expose both edge portions 1A of the resistor 1 and cover the central portion. This insulating film 40 corresponds to the protective film 4 described above. Thereafter, if it is necessary to improve solderability, a solder layer (not shown) such as Sn may be formed on both edge portions 1A of the resistor 1 by plating.

  Finally, as shown in FIG. 4B, the resistor 1, the prepreg 20, the substrate 30, and the insulating film are cut by surrounding the resistor 1 along the vertical cutting line L1 and the horizontal cutting line L2. The integrated 40 is divided into chips. Thereby, a plurality of chip resistors A as shown in FIGS. 1 and 2 can be obtained.

  Therefore, according to the chip resistor A of the present embodiment, even when the resistor 1 has poor strength due to the cut portion 1a, the wire bonding is performed while the resistor 1 is supported by the lower base material 3. Since it is mounted on a wiring board or the like by connection, the entire chip resistor A can have sufficient strength. Moreover, heat dissipation can be made favorable by the base material 3 having a larger volume than the resistor 1. According to the chip resistor manufacturing method of this embodiment, the wire bonding connection type chip resistor A having the above-described excellent effects can be easily mass-produced.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the chip resistor according to the present invention can be varied in design in various ways.

It is a perspective view which shows one Embodiment of the chip resistor concerning this invention. It is sectional drawing which follows the II-II line of FIG. It is explanatory drawing for demonstrating the manufacturing method of the chip resistor shown in FIG. It is explanatory drawing for demonstrating the manufacturing method of the chip resistor shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resistor 1a Notch part 1A Both edges 2 Adhesive layer 3 Base material 4 Protective film 10 Metal plate 20 Prepreg 30 Substrate 40 Insulating film A Chip resistor

Claims (5)

A chip resistor having a layered resistor,
An insulating base material joined to one side of the resistor so as to support the entire resistor;
A protective film covering a part of the resistor from above the base material so as to expose both edge portions of the resistor as electrode pads for wire bonding;
A chip resistor comprising: a chip resistor.   The chip resistor according to claim 1, wherein the resistor is formed with a cut portion.   The chip resistor according to claim 1 or 2, wherein the resistor and the base material are bonded via an insulating adhesive layer. Joining a metal plate as a material of the resistor and an insulating substrate as a base material;
Etching the metal plate; and
Forming a protective film on the substrate so as to expose a part of the metal plate as an electrode pad portion for wire bonding and cover the remainder;
Dividing the metal plate, the substrate, and the protective film into a single chip; and
A method of manufacturing a chip resistor, comprising:   The method for manufacturing a chip resistor according to claim 4, wherein when the metal plate is etched, a cut portion is formed in the metal plate.

Images