JP2008103462A - Chip type network resistor, surface mounting component, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability under the environment where temperature changes to a large extent. <P>SOLUTION: The chip type network resistor 10 does not include a flat surface of electrode terminals D1 to D8 for the soldering process and is formed in the shape of groove formed along the recessed part provided to and end part of an alumina substrate 22 as the mounting component itself. The recessed part of this alumina substrate 22 is formed by the cutting process using a grind stone and the electrode terminals D1 to D8 are constituted by depositing a film of electrode material such as NiCr (nickel-chrome), and Cu (copper) or the like on this recessed part. This recessed part is formed orthogonal to a surface being in contact with a printed circuit board. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface-mount component having electrode terminals for performing soldering, and more particularly to a chip-type network resistor in which a plurality of resistance elements are mounted in one chip component.

  For the purpose of improving the mounting density and reducing the deviation between elements as much as possible, a chip network resistor in which a plurality of resistance elements are mounted in one chip component is used. Various methods are disclosed as a manufacturing method of such a chip type network resistor (for example, refer to Patent Documents 1 to 3).

  In recent years, such a chip network resistor has been used in various electronic products. Therefore, higher reliability has been demanded for the chip-type network resistor. In particular, when such electronic products are used in automotive electrical components, chip-type network resistors themselves are also exposed to severe temperature environments, and therefore, there is a demand for improved reliability in environments where temperature changes are severe. .

JP 2002-198201 A JP 2002-367817 A JP 2004-111458 A

  An object of the present invention is to provide a surface-mounted component and a chip-type network resistor that can improve reliability in an environment where temperature change is severe.

[Surface mount parts]
In order to achieve the above object, the present invention provides a mounting component body formed in a plate shape,
It has an electrode terminal provided at the end of this mounting component body,
A recess is formed at an end of the mounting component body, and at least a part of the electrode terminal is formed in the recess.

  According to the present invention, since at least a part of the electrode terminal is formed in the recess formed at the end of the mounted component body, it is strong against the heat cycle test in the soldered state, and the temperature change Reliability is improved in a severe environment.

  Preferably, the mounting component main body is fixed to a printed wiring board, and the concave portion is formed to be orthogonal to a surface in contact with the printed wiring board.

Preferably, the recess is formed by cutting the mounting component body with a grindstone,
The electrode terminal is configured by depositing an electrode material on the recess.

[Chip type network resistor]
Further, the chip type network resistor of the present invention includes a mounting component body formed in a plate shape,
It has an electrode terminal provided at the end of this mounting component body,
A recess is formed at an end of the mounting component body, and at least a part of the electrode terminal is formed in the recess.

[Surface mount component manufacturing method]
The method for manufacturing a surface-mounted component according to the present invention forms a recess by cutting an end portion of a mounting component body formed in a plate shape with a grindstone,
An electrode terminal is formed by depositing an electrode material on at least a part of the recess.

[Chip-type network resistor manufacturing method]
Moreover, the manufacturing method of the chip type network resistor of the present invention forms a recess by cutting the end of the mounting component body formed in a plate shape with a grindstone,
An electrode terminal is formed by depositing an electrode material on at least a part of the recess.

  As described above, according to the present invention, since at least a part of the electrode terminal is formed in the recess formed at the end of the mounting component body, the reliability in an environment where the temperature change is severe can be improved. The effect of being able to be obtained can be obtained.

[background]
First, in order to help understanding of the present invention, its background and outline will be described.

  As an example of a conventional chip type network resistor (chip type metal thin film network resistor), an appearance of a chip type network resistor 110 in which four resistance elements are mounted in one chip component is shown in FIG. FIG. 1A is a top view of the chip network resistor 110, and FIG.

  This chip-type network resistor 110 is formed as a composite component in which four resistance elements are formed on a high-purity alumina substrate 22 which is a mounting component body. A protective film 21 is formed on the four resistance elements, and eight electrode terminals D11 to D18 are formed at portions where the protective film 21 is not formed.

  FIG. 2 shows a circuit configuration of the chip type network resistor 110 shown in FIG. As shown in FIG. 2, between the electrode terminal D11 and the electrode terminal D15, between the electrode terminal D12 and the electrode terminal D16, between the electrode terminal D13 and the electrode terminal D17, and between the electrode terminal D14 and the electrode terminal D18. A resistive element is formed between each of them.

  Next, FIG. 3 shows a cross-sectional view of the chip-type network resistor 110 shown in FIG. 1 on the A-A ′ plane. As shown in FIG. 3, the chip-type network resistor 110 includes a resistor 25 and electrode bodies 23 and 24 on an alumina substrate 22, and protects the resistor 25 and electrode bodies 23 and 24 from the outside. Therefore, a protective film 21 is formed. Further, back electrodes 28 and 29 are formed on the back side of the alumina substrate 22 so as to face the electrode bodies 23 and 24. A side electrode 34 electrically connected to the electrode body 23 and the back electrode 28 is formed so as to cover the left side surface of the alumina substrate 22, and a plating film 32 is formed on the side electrode 34. . The side electrode 34 and the plating film 32 constitute an electrode terminal D18. Similarly, a side electrode 35 electrically connected to the electrode body 24 and the back electrode 29 is formed so as to cover the right side surface of the alumina substrate 22, and a plating film 33 is formed on the side electrode 35. ing. The side electrode 35 and the plating film 33 constitute an electrode terminal D14.

Next, FIG. 4 shows a state where the chip type network resistor 110 is mounted on the printed wiring board 40.
As shown in FIG. 4, when the chip-type network resistor 110 is mounted on the printed wiring board 40, the electrode terminals D14 and D18 are connected to the land pattern on the printed wiring board 40 by solders 30 and 31, respectively. Is done. In this case, the shape of the solders 30 and 31 (fillet shape) becomes a parabolic shape as shown in FIG. 4 due to the surface tension at the time of melting.

  Next, FIG. 5 shows a state in which connection failure occurs as a result of the heat cycle test performed on the chip type network resistor 110 mounted on the printed wiring board 40 in this way.

  Here, the heat cycle test is a test for evaluating resistance to a temperature change by alternately repeating a test object in different environments of a high temperature state and a low temperature state.

  In the example shown in FIG. 5, the electrode terminal D <b> 14 is destroyed due to exceeding the limit in the heat cycle test, and the electrical connection between the solder 30 and the electrode body 24 is not secured, resulting in a poor connection. Recognize.

[Embodiment]
Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 6 shows the appearance of a chip network resistor (chip metal thin film network resistor) 10 according to an embodiment of the present invention in which four resistor elements are mounted in one chip component. FIG. 6A is a top view of the chip-type network resistor 10, and FIG. 6B is a side view. In FIG. 6, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

  In this embodiment, the case where four resistance elements are mounted in one chip component will be described. However, the present invention is similarly applied to any type of chip network resistor. Is something that can be done.

  The chip type network resistor 10 of the present embodiment is different from the conventional chip type network resistor 110 shown in FIG. 1 in that the surfaces of the electrode terminals D1 to D8 for performing soldering are not flat and are mounted components. It is a point which is groove-shaped along the recessed part provided in the edge part of the alumina substrate 22 which is a main body. The concave portion of the alumina substrate 22 is formed by cutting with a grindstone, and the electrode terminals D1 to D8 are formed by depositing an electrode material such as NiCr (nickel chromium) or Cu (copper) on the concave portion. ing. Specific methods for depositing the electrode material include a method of depositing by vapor deposition and a method of depositing by sputtering.

  An enlarged view of the electrode terminal D1 is shown in FIG. FIG. 7A is a perspective view of the electrode terminal D1, and FIG. 7B is a top view of the electrode terminal D1. As shown in FIG. 7A and FIG. 7B, the electrode terminal D1 is formed on the recess 27 provided at the end of the alumina substrate 22, thereby forming a groove shape along the recess 27. It has become. And this recessed part 27 is formed in the vertical direction so that the alumina substrate 22 may be orthogonal to the surface which contacts a printed wiring board.

  Next, a manufacturing method of the chip network resistor 10 of the present embodiment will be described with reference to the flowchart of FIG.

First, electrode bodies 23 and 24 and a resistor 25 are formed on a high-purity alumina substrate 22 that functions as an insulating substrate (S101). Specifically, an electrode pattern and a resistor pattern are prepared by wet etching using a photoresist, and heat treatment (stabilization treatment) is performed in an N ₂ (nitrogen) atmosphere, whereby the electrode bodies 23 and 24 and the resistor 25 are formed. Generate.

  Since a plurality of chip network resistors are simultaneously formed on the alumina substrate 22 formed in a plate shape, laser scribing is then performed in which perforations for dividing each chip network resistor are formed by a laser. (S102).

  Next, laser trimming is performed in order to adjust the resistance value of each formed resistance element within a standard value (S103). Since a specific method of laser trimming is not directly related to the present invention, detailed description thereof is omitted here.

  Next, the protective film 21 is formed on the electrode bodies 23 and 24 and the resistor 25 using an epoxy resin or the like (S104). FIG. 9 shows an example of the appearance after the steps so far are completed.

  Thereafter, after the back electrodes 28 and 29 are formed on the back surface of the alumina substrate 22, primary division for dividing the alumina substrate 22 in the vertical direction is performed (S105). The external appearance after the primary division is shown in FIG. As shown in FIG. 10, it can be seen that the chip-type network resistor 10 has a strip shape in which the alumina substrate 22 is primarily divided and arranged in the vertical direction as an example. The process so far is the same as the process of generating a conventional chip network resistor.

  Next, a recess 27 is formed by performing groove processing on the side surface of the part after the primary division (S106). As shown in FIG. 10, a specific method for grooving the side surface is to use a grindstone such as a dicing cutter (saw) or the like to fix the central portion of the portion where the electrode bodies 23 and 24 are formed using a grindstone. This is done by cutting only the depth.

  The specific size of the groove is preferably, for example, a groove width of 200 to 300 μm and a groove depth of about 100 to 200 μm. This is because if the depth of the groove is increased too much, the time required for the groove processing becomes too long, and there is a problem that contact failure occurs when the probe is brought into contact with the electrode terminal during inspection. If the depth of the groove is too deep, it may be difficult to deposit the electrode material uniformly to the depth of the groove when depositing the electrode material. On the other hand, if the depth of the groove is too shallow, no effect can be obtained because the groove is completely filled when an electrode material is deposited or plating is performed in a later step.

  After this grooving is completed and the recess 27 is formed, a side electrode deposition process for forming an electrode on the side surface of the alumina substrate 22 is performed (S107). Specifically, NiCr (nickel chromium) and Cu (copper) are vapor-deposited on the side surface of the alumina substrate 22 as electrode materials. By this side electrode deposition process, the electrode material adheres to the surface of the recess 27 provided at the end of the alumina substrate 22 to form the side electrodes 34 and 35.

  Thereafter, the substrate is divided into two pieces (divided into individual pieces) by dividing the alumina substrate 22 connected in a strip shape in the vertical direction (S108).

  Finally, Ni (nickel) + solder plating or Ni (nickel) + tin plating is performed on the side electrodes 34 and 35, the back electrodes 28 and 29, and the electrode bodies 23 and 24 by so-called barrel plating. Thus, the plating films 32 and 33 are formed, and the electrode terminals D1 to D8 are completed (S109).

  Next, the results of the heat cycle test performed under the same conditions for the chip network resistor of this embodiment and the conventional chip network resistor will be described. In this heat cycle test, an environmental load of 30 minutes in an environment of −40 ° C. and 30 minutes in an environment of 120 ° C. is defined as one cycle, and 10 chip type network resistors having four resistance elements are formed. It was given.

  In the conventional chip type network resistor 110 as shown in FIG. 1 in which no groove is provided in the electrode terminal, disconnection occurs at two resistance elements after 24 cycles, and at one additional resistance element at 40 cycles. Disconnection occurred. Further, in 72 cycles, disconnection occurred in two resistance elements, and in 102 cycles, disconnection occurred in two more resistance elements. In other words, in the conventional chip type network resistor 110, disconnection occurred in seven of the 40 resistance elements after the end of the 102 cycles of the test.

  On the other hand, in the chip type network resistor 10 of the present embodiment as shown in FIG. 6, no disconnection occurred in one of the 40 resistance elements after the end of the 102 cycle test.

  Based on the result of this heat cycle test, it can be seen that the chip-type network resistor 10 of the present embodiment has improved reliability against temperature changes as compared to the conventional chip-type network resistor 110.

  Next, the reason why the chip network resistor 10 of the present embodiment is more reliable with respect to temperature changes than the conventional chip network resistor 110 will be described.

  (1) First, a state in which the conventional chip network resistor 110 is mounted on the printed wiring board 40 is shown in FIG. 11A, and the chip network resistor 10 of the present embodiment is mounted on the printed wiring board 40. FIG. 11 (b) shows the situation when this is done.

  As shown in FIG. 11B, in the chip network resistor 10 of the present embodiment, the solder 30 enters the groove on the side surface of the electrode terminal D4, and soldering is performed more firmly. I understand that. Although not shown in FIG. 11 (b), the solder 30 that has entered the groove on the side surface of the electrode terminal D4 is expected to rise to a position higher than usual due to surface tension, and the soldering strength is further increased. Conceivable.

  (2) Further, since the inside of the groove on the side surface of the electrode terminal D4 is soldered, even when a force that peels the side surface of the electrode terminal D4 from the alumina substrate 22 is generated, the surface of the groove on the side surface of the electrode terminal D4 This peeling force is dispersed due to the curvature of. Therefore, compared with the conventional chip type network resistor 110 in which the side surface of the electrode terminal D14 is flat, an effect of preventing the side surface of the electrode terminal D4 from being peeled from the alumina substrate 22 can be expected.

  (3) In addition, since the base of the film-forming surface is cut using a grindstone such as a dicing cutter (saw), the electrode material and the alumina substrate that is the mounting component main body formed by roughening the surface of the base The adhesion force with 22 is increased.

  (4) Furthermore, when the widths of the electrode terminals are the same, the chip type network resistor 110 of the present embodiment has an effective bonding area between the electrode terminals D1 to D8 and the alumina substrate 22 due to the provision of the recesses 27. Increase. Therefore, it is considered that the bonding force between the electrode terminals D1 to D8 and the alumina substrate 22 increases.

  Due to the combined effect of the reason described above, the chip network resistor 10 according to the present embodiment can improve the reliability in an environment where the temperature change is severe as compared with the conventional chip network resistor 110. It becomes possible.

  As a secondary effect, since the electrode terminals D1 to D8 are formed in a groove shape, even if an object collides with the edge portions of the electrode terminals D1 to D8, the electrode terminals D1 to D8 are not easily damaged. For example, even when a metal ball collides with the electrode terminals D1 to D8 during barrel plating in the electrode plating process (S109) in the flowchart shown in FIG. 8, the side surface grooves of the electrode terminals D1 to D8 are damaged by the collision. hard. Therefore, compared with the conventional chip type network resistor 110 in which the electrode terminals D11 to D18 are not groove-shaped, it is possible to reduce the probability that a defect such as a connection failure occurs.

  In the present embodiment, the case where the electrode terminals D <b> 1 to D <b> 8 are formed in the entire recess 27 provided at the end of the alumina substrate 22 has been described. Similar effects can be obtained if the electrode terminals D1 to D8 are formed.

[Modification]
In the above embodiment, the chip-type metal thin film network resistor has been described. However, the present invention is not limited to this, and solder such as a chip-type resistor, a chip-type capacitor, and various electronic components compatible with reflow can be used. The present invention can be similarly applied to any surface mount component having an electrode terminal for attaching.

It is an external view of the conventional chip type network resistor 110. It is a figure which shows the circuit structure of the chip | tip network resistor 110 shown in FIG. It is sectional drawing in the A-A 'surface of the chip-type network resistor 110 shown in FIG. FIG. 2 is a diagram illustrating a state in which the chip network resistor 110 illustrated in FIG. 1 is mounted on a printed wiring board 40. It is a figure which shows a mode when it becomes a connection defect as a result of performing a heat cycle test with respect to the chip-type network resistor 110 mounted on the printed wiring board 40. FIG. 1 is an external view of a chip network resistor 10 according to an embodiment of the present invention. It is an enlarged view of electrode terminal D1 in chip type network resistor 10 of one embodiment of the present invention. It is a flowchart which shows the manufacturing method of the chip type network resistor 10 of one Embodiment of this invention. It is a figure which shows an example of the external appearance after the process until it forms the protective film 21 on the electrode bodies 23 and 24 and the resistor 25 is complete | finished. It is a figure which shows an example of the external appearance of components after primary division is complete | finished. FIG. 11A shows a state in which the conventional chip type network resistor 110 is mounted on the printed wiring board 40, and the chip type network resistor 10 according to one embodiment of the present invention on the printed wiring board 40. It is a figure (FIG.11 (b)) which shows a mode at the time of mounting.

Explanation of symbols

D1 to D8 Electrode terminal 10 Chip type network resistor D11 to D18 Electrode terminal 21 Protective film 22 Alumina substrate 23, 24 Electrode body 25 Resistor 27 Recess 28, 29 Back electrode 30, 31 Solder 32, 33 Plating film 34, 35 Side surface Electrode 40 Printed wiring board S101 to S109 Step 110 Chip type network resistor

Claims (6)

A mounting component body formed in a plate shape;
It has an electrode terminal provided at the end of this mounting component body,
A surface-mount component in which a recess is formed at an end of the mounting component body, and at least a part of the electrode terminal is formed in the recess.   The surface-mounted component according to claim 1, wherein the mounting component body is fixed to a printed wiring board, and the concave portion is formed to be orthogonal to a surface in contact with the printed wiring board. The recess is formed by cutting the mounting component body with a grindstone,
The surface-mount component according to claim 1, wherein the electrode terminal is configured by depositing an electrode material on the recess. A mounting component body formed in a plate shape;
It has an electrode terminal provided at the end of this mounting component body,
A chip type network resistor in which a concave portion is formed at an end portion of the mounting component body, and at least a part of the electrode terminal is formed in the concave portion. A recess is formed by cutting the end of the mounting component body formed in a plate shape with a grindstone,
A method of manufacturing a surface-mounted component that constitutes an electrode terminal by depositing an electrode material on at least a part of the recess. A recess is formed by cutting the end of the mounting component body formed in a plate shape with a grindstone,
A method for manufacturing a chip-type network resistor comprising an electrode terminal by depositing an electrode material on at least a part of the recess.

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