WO2012039175A1 - Method for producing metal plate low-resistance chip resistor - Google Patents

Abstract

The purpose of the present invention is to provide a method for producing a metal plate low-resistance chip resistor for which a protective film can be formed easily without being affected by the width of the metal plate resistor at the stripe shaped parts and for which the protective film width can be adjusted according to the variations in thickness in the direction of the width of the metal plate resistor. The purpose is also for the metal plate low-resistance chip resistor to have increased freedom in adjustment of the width of the protective film. To do so, a protective film forming step (step S13) that forms a protective film on the front surface and back surface of a metal plate resistor is carried out first and a slit forming step (step S14) that forms a slit in the metal plate resistor and forms the metal plate resistor into a shape having the stripe shaped parts and connecting parts is carried out thereafter. In addition, a metal plate resistor thickness measurement step (step 12) that measures the thickness at various positions along the width of the metal plate resistor for which the protective film is formed is carried out before the protective film forming step (step S13), and in the protective film forming step (step S13), the width of the protective film is set according to the thickness at each position that has been measured along the width of the metal plate resistor.

Description

Metal plate low resistance chip resistor manufacturing method

The present invention relates to a method for manufacturing a chip resistor using a resistive metal plate.

In various control circuits such as a power supply device and a motor speed control circuit, a means for detecting current is required. There are various means for detecting the current, but in general, electronic components such as a shunt resistor are often used. A chip resistor is known as a resistor applied to such a shunt resistor. Of these chip resistors, a resistive metal plate is mainly applied to manufacture a chip resistor having a very low resistance value such as several mΩ. A low resistance chip resistor manufactured using such a resistance metal plate is generally called a metal plate low resistance chip resistor.

As shown in FIGS. 16A to 16C, the metal plate low resistance chip resistor 1 has a rectangular parallelepiped appearance, and is manufactured using the resistance metal plate 2. Protective films 3a and 3b are formed on the front surface 2a and the back surface 2b of the resistance metal plate 2, respectively. These protective films 3a and 3b are electrically insulating films. Further, the surfaces (that is, the width of the surface 2a) of both end portions 2e and 2f in the length direction of the resistance metal plate 2 on which the protective films 3a and 3b are not formed (left and right directions in FIGS. 16B and 16C). Electrode plating films 4a and 4b are formed on both end portions 2a-1 and 2a-2 in the direction, both end portions 2b-1 and 2b-2 in the width direction of the back surface 2b, and both end surfaces 2c and 2d). .

Regarding each dimension (unit: mm) of the chip resistor 1, for example, the total length L1 of the chip resistor 1 is 1.6 ± 0.1 (tolerance), and the length C of the electrode plating films 4a and 4b is 0.2. ± 0.1 (tolerance), the width W of the chip resistor 1 is 0.8 ± 0.1 (tolerance), and the thickness H of the chip resistor 1 is 0.3 ± 0.1 (tolerance) It is prescribed. Each dimension of the chip resistor 1 including these tolerances is defined based on dimensional restrictions when the chip resistor 1 is mounted on the circuit board. The length L2 of the protective films 3a and 3b is a difference (L1-2 × C) between the total length L1 of the chip resistor 1 and the length (total length) 2 × C of the electrode plating films 4a and 4b on both sides. . In other words, L2 is also the length of the portion of the resistance metal plate 2 covered by the protective films 3a and 3b. T is the thickness of the resistance metal plate 2, and L3 is the length of the resistance metal plate 2.

And conventionally, the metal plate low resistance chip resistor 1 having the structure as shown in FIG. 16 is formed by the strip-like resistance metal plate cutting step (step S1) and the slit forming step (step S2) shown in the process flowchart of FIG. By sequentially performing the protective film forming step (step S3), the electrode plating film forming step (step S4), the strip portion cutting step (step S5), and the strip portion cutting step (step S6). Was manufacturing.

The slit forming step (step S2) and the protective film forming step (step S3) will be further described with reference to FIGS. The strip-shaped resistance metal plate cutting step (step S1), the electrode plating film forming step (step S4), the strip-shaped portion cutting step (step S5), and the strip-shaped portion cutting step (step S6) are shown in FIG. The strip-shaped resistive metal plate cutting step (step S11), the electrode plating film forming step (step S15), the strip portion cutting step (step S16), and the strip portion cutting step (step S17) shown in FIG. Details of these will be described later.

As shown in FIGS. 18A to 18C, in the slit forming step (step S2), a plurality of (six in the illustrated example) slits 6 are formed in the rectangular resistance metal plate 2B. The resistive metal plate 2B is cut from the strip-shaped resistive metal plate 2A (see FIG. 2) in the strip-shaped resistive metal plate cutting step (step S1). The slits 6 extend in the length direction of the resistance metal plate 2B (up and down direction in FIG. 18B), and are parallel to each other in the width direction of the resistance metal plate 2B (left and right direction in FIG. 18B). ing. The position where the slit 6 is formed is set with the positioning mark 5 as a reference. By forming such a plurality of slits 6, the resistance metal plate 2 </ b> B has a plurality (four in the illustrated example) of strip-like portions 7 extending in the length direction of the resistance metal plate 2 </ b> B and the plurality of strip-like shapes. It becomes a shape which has the connection part 8 which connects the both ends of the length direction (up-down direction of FIG.18 (b)) of the part 7 respectively.

As shown in FIGS. 19A to 19C, in the next protective film forming step (step S3), a plurality of (four in the illustrated example) protective films 3A and 3B are formed by screen printing or the like. Each strip 7 is formed on the front surface 2B-1 and the back surface 2B-2 of the resistance metal plate 2B, respectively. These protective films 3A and 3B extend in the length direction of the resistance metal plate 2B, and are parallel to each other in the width direction of the resistance metal plate 2B. The positions where the protective films 3A and 3B are formed are set with the positioning mark 5 as a reference.

Note that, as prior art documents disclosing a method for manufacturing a chip resistor, for example, there are the following Patent Documents 1 and 2.

JP 2009-218552 A International Publication No. 2008/018219 Pamphlet

In the conventional method of manufacturing a metal plate low resistance chip resistor, the slit 6 is formed before the protective films 3A and 3B. That is, after forming the strip-shaped portion 7 by forming the slit 6 in the resistive metal plate 2B, the protective films 3A and 3B are formed on the strip-shaped portion 7. Therefore, the conventional method for manufacturing a metal plate low resistance chip resistor has the following problems.

That is, when the slit 6 is formed before the protective films 3A and 3B, the protective films 3A and 3B are formed on the front surface 2B-1 and the back surface 2B-2 of the very narrow resistance metal plate 2B in the strip-shaped portion 7. I have to do it. For this reason, it is difficult to form the protective films 3A and 3B. In addition, when further downsizing of the chip resistor 1 is required, the width of the resistance metal plate 2B in the strip portion 7 is further narrowed, so that it becomes more difficult to form the protective films 3A and 3B. . Further, when forming the protective films 3A and 3B, the paste is generally patterned by a screen printing method. However, in order to further improve the dimensional accuracy, a photolithography method is applied. And when applying this photolithography method, if the slit 6 is formed ahead of the protective films 3A and 3B, this complicates the construction method.

Further, the strip-shaped resistive metal plate 2A (see FIG. 2) used for manufacturing the chip resistor 1 is manufactured by repeating the annealing process and the rolling process in order to obtain a desired thickness. However, the thickness of the manufactured strip-shaped resistance metal plate 2A is not completely uniform, and the thickness varies particularly in the width direction of the resistance metal plate 2A. For this reason, the thickness variation in the width direction also occurs in the resistance metal plate 2B cut from the strip-shaped resistance metal plate 2A.

Such variation in the thickness of the resistance metal plate 2B in the width direction causes variation in the resistance value of the chip resistor 1. On the other hand, the resistance value of the chip resistor 1 is determined by the width W, length L2, and thickness T (see FIG. 16) of the portion of the resistive metal plate 2 covered with the protective films 3a and 3b. That is, it is determined by the later-described equations (1) and (3). For this reason, in the manufacturing process of the chip resistor 1, the widths L2 ₁ , L2 ₂ , L2 ₃ , L2 of the protective films 3A, 3B shown in FIG. 19 according to the thickness variation in the width direction of the resistive metal plate 2B. By adjusting ₄ , it is necessary to reduce the variation in resistance value of the chip resistor 1. In this case, the allowable range of adjustment for the widths L2 ₁ , L2 ₂ , L2 ₃ and L2 _{4 of} the protective films 3A and 3B (that is, the length L2 of the protective films 3a and 3b in the chip resistor 1) should be as large as possible. desirable.

On the other hand, as shown in FIG. 20, in the case of the dimension example of the chip resistor 1 as described above, the allowable adjustment range of the length L2 of the protective films 3a and 3b in the conventional manufacturing method is 0.4 mm. . That is, since the slit 6 is formed before the protective films 3A and 3B, the length L3 of the resistive metal plate 2 is determined before the length L2 of the protective films 3a and 3b in the chip resistor 1, The total length L1 of the chip resistor 1 is determined. When the total length L1 of the chip resistor 1 is 1.6 mm, for example, the total length 2 × C of the electrode plating films 4a and 4b is 0.6 mm at the longest (= 2 × (0.2 + 0.1)) and 0.2 mm at the shortest. In the case of (= 2 × (0.2−0.1)), the lengths L2 of the protective films 3a and 3b are 0.9 mm and 1.3 mm, respectively. Therefore, the allowable adjustment range of the length L2 of the protective films 3a and 3b is 0.4 mm (= 1.3−0.9). Even when the total length L1 of the chip resistor 1 is set to 1.5 mm (= 1.6-0.1) or 1.7 mm (= 1.6 + 0.1), the same adjustment allowable range is obtained.

As a method for reducing the variation in resistance value of the chip resistor due to the variation in thickness in the width direction of the resistance metal plate, there is a method of trimming the resistance metal plate to adjust the resistance value. However, when a resistor metal plate is trimmed, a hot spot is generated in the chip resistor when a chip resistor to which the trimmed resistor metal plate is applied is connected to a load and a current is passed through the chip resistor. Therefore, there is a possibility that a problem that load characteristics such as life characteristics of the chip resistor are deteriorated may occur. For this reason, the variation in the resistance value of the chip resistor 1 due to the variation in the thickness in the width direction of the resistance metal plate 2B is not a method of trimming the resistance metal plate 2B, but the width L2 ₁ , of the protective films 3A and 3B. It is necessary to carry out the method by adjusting L2 ₂ , L2 ₃ , and L2 ₄ .

Therefore, in view of the above circumstances, the present invention can easily form a protective film without being affected by the width of the resistive metal plate in the strip-shaped portion, and according to the thickness variation in the width direction of the resistive metal plate. The width of the protective film (the length of the protective film in the chip resistor) can be adjusted, and further, the allowable range of adjustment of the width of the protective film (the length of the protective film in the chip resistor) can be increased. It is an object of the present invention to provide a method for manufacturing a metal plate low resistance chip resistor.

The manufacturing method of the metal plate low resistance chip resistor of the first invention that solves the above problem is a manufacturing method of a chip resistor using a rectangular or strip-shaped resistance metal plate,
A protective film forming step of forming a plurality of protective films extending in the length direction of the resistive metal plate in the width direction of the resistive metal plate with respect to each of the front and back surfaces of the resistive metal plate;
Forming a slit extending in the length direction of the resistive metal plate between the adjacent protective films in the width direction and outside the protective film located on both sides of the width direction in the resistive metal plate; The plurality of strip-shaped portions having a width wider than the protective film and extending in the length direction of the resistance metal plate, and both ends in the length direction of the plurality of strip-shaped portions, respectively. A slit forming step to form a connecting portion to be connected;
An electrode plating film forming step for forming an electrode plating film on the surfaces of both end portions in the width direction of the strip-shaped part where the protective metal plate is not formed and the resistance metal plate is exposed;
A strip-shaped portion cutting step of cutting the strip-shaped portion from the connecting portion;
A strip-shaped portion cutting step for cutting the strip-shaped portion into a plurality of pieces,
The chip resistor is manufactured by performing sequentially.

Moreover, the manufacturing method of the metal plate low resistance chip resistor of the second invention is the manufacturing method of the metal plate low resistance chip resistor of the first invention,
Conducting a resistance metal plate thickness measurement step of measuring the thickness at each position in the width direction of the resistance metal plate forming the plurality of protective films before the protective film formation step,
In the protective film forming step, the width of each of the plurality of protective films is set according to the thickness at each position in the width direction of the resistive metal plate measured in the resistive metal plate thickness measuring step. And

Moreover, the manufacturing method of the metal plate low resistance chip resistor of the third invention is a manufacturing method of a chip resistor using a rectangular or strip-shaped resistance metal plate,
A protective film forming step of forming a plurality of protective films extending in the length direction of the resistive metal plate in the width direction of the resistive metal plate with respect to each of the front and back surfaces of the resistive metal plate;
Cutting the resistive metal plate at a cutting position extending in the length direction of the resistive metal plate between the protective films adjacent in the width direction and outside the protective film located on both sides of the width direction. A strip-shaped cutting step of cutting a plurality of strip-shaped portions having a width wider than the protective film and extending in the length direction of the resistance metal plate;
An electrode plating film forming step for forming an electrode plating film on the surfaces of both end portions in the width direction of the strip-shaped part where the protective metal plate is not formed and the resistance metal plate is exposed;
An individual piece cutting step of cutting the strip-shaped portion into a plurality of pieces,
The chip resistor is manufactured by performing sequentially.

Moreover, the manufacturing method of the metal plate low resistance chip resistor of the fourth invention is the manufacturing method of the metal plate low resistance chip resistor of the third invention,
Conducting a resistance metal plate thickness measurement step of measuring the thickness at each position in the width direction of the resistance metal plate forming the plurality of protective films before the protective film formation step,
In the protective film forming step, the width of each of the plurality of protective films is set according to the thickness at each position in the width direction of the resistive metal plate measured in the resistive metal plate thickness measuring step. And

According to the metal plate low resistance chip resistor manufacturing method of the first aspect of the invention, there is provided a chip resistor manufacturing method using a rectangular or strip-shaped resistance metal plate, for each of the front surface and the back surface of the resistance metal plate. A protective film forming step of forming a plurality of protective films extending in the length direction of the resistive metal plate in the width direction of the resistive metal plate, between the adjacent protective films in the width direction, and in the width direction. By forming slits extending in the length direction of the resistance metal plate on the resistance metal plate outside the protection film located on both sides of the resistance metal plate, the resistance metal plate has a wider width than the protection film. And a slit forming step for forming a shape having a plurality of strip-shaped portions extending in the length direction of the resistance metal plate and connecting portions respectively connecting both ends in the length direction of the plurality of strip-shaped portions, and the protection A film is formed An electrode plating film forming step for forming an electrode plating film on the surfaces of both end portions in the width direction of the strip-shaped portion where the resistance metal plate is exposed, and a strip-shaped configuration in which the strip-shaped portion is cut from the connecting portion. Since the chip resistor is manufactured by sequentially performing a part cutting process and a strip part cutting process for cutting the strip part into a plurality of pieces, a slit (that is, a strip shape) The protective film is formed before the part.
For this reason, for example, even if the chip resistor is required to be further reduced in size and the width of the resistive metal plate in the strip portion is further narrowed, it is easily affected by the width of the resistive metal plate in the strip portion. A protective film can be formed. In addition, the allowable range of adjustment of the width of the protective film (the length of the protective film in the chip resistor) can be increased (see FIG. 8: details will be described later).

According to the metal plate low resistance chip resistor manufacturing method of the second invention, in the metal plate low resistance chip resistor manufacturing method of the first invention, in the width direction of the resistance metal plate forming the plurality of protective films The resistance metal plate thickness measurement step for measuring the thickness at each position is performed before the protective film formation step, and the resistance metal plate measured in the resistance metal plate thickness measurement step in the protective film formation step Since the width of each of the plurality of protective films is set according to the thickness at each position in the width direction, the thickness of the resistance metal plate in the width direction is added to the effect of the first invention. The width of the protective film (the length of the protective film in the chip resistor) can also be adjusted according to the variation in thickness. For this reason, the variation in the resistance value of the chip resistor due to the variation in the thickness in the width direction of the resistance metal plate can be reduced.

According to the metal plate low resistance chip resistor manufacturing method of the third aspect of the invention, there is provided a chip resistor manufacturing method using a rectangular or strip-shaped resistance metal plate, and each of the front and back surfaces of the resistance metal plate. A protective film forming step of forming a plurality of protective films extending in the length direction of the resistive metal plate in the width direction of the resistive metal plate, between the adjacent protective films in the width direction, and in the width direction. The resistance metal plate is wider than the protection film by cutting the resistance metal plate at a cutting position extending in the length direction of the resistance metal plate outside the protection film located on both sides of the resistance metal plate. A strip-shaped cutting step for cutting a plurality of strip-shaped portions extending in the length direction of the strip, and the surface of both end portions in the width direction of the strip-shaped portion where the protective metal plate is exposed without forming the protective film In contrast, an electrode plating film is formed. Since the chip resistor is manufactured by sequentially performing the electrode plating film forming step and the individual piece cutting step of cutting the strip portion into a plurality of pieces, the strip portion A protective film is formed prior to cutting off.
For this reason, for example, even if the chip resistor is required to be further reduced in size and the width of the resistive metal plate in the strip portion is further narrowed, it is easily affected by the width of the resistive metal plate in the strip portion. A protective film can be formed. In addition, the allowable range of adjustment of the width of the protective film (the length of the protective film in the chip resistor) can be increased (see FIG. 8: details will be described later).

According to the metal plate low resistance chip resistor manufacturing method of the fourth invention, in the metal plate low resistance chip resistor manufacturing method of the third invention, in the width direction of the resistance metal plate forming the plurality of protective films The resistance metal plate thickness measurement step for measuring the thickness at each position is performed before the protective film formation step, and the resistance metal plate measured in the resistance metal plate thickness measurement step in the protective film formation step Since the width of each of the plurality of protective films is set according to the thickness at each position in the width direction, the thickness of the resistance metal plate in the width direction is added to the effect of the third invention. The width of the protective film (the length of the protective film in the chip resistor) can also be adjusted according to the variation in thickness. For this reason, the variation in the resistance value of the chip resistor due to the variation in the thickness in the width direction of the resistance metal plate can be reduced.

It is a flowchart which shows the manufacturing process of the metal plate low resistance chip resistor which concerns on the embodiment of this invention. (A) is a perspective view of the strip | belt-shaped resistance metal plate for demonstrating a strip | belt-shaped resistance metal plate cutting process, (b) is a top view of the rectangular-shaped resistance metal plate for demonstrating a strip | belt-shaped resistance metal plate cutting process. (A) is a perspective view of a resistance metal plate for explaining the resistance metal plate thickness measurement step, (b) is a plan view of the resistance metal plate for explaining the resistance metal plate thickness measurement step, and (c) is a plan view of the resistance metal plate. It is a cross-sectional enlarged view (AA arrow directional cross-sectional enlarged view of (b)) of a resistance metal plate for demonstrating a resistance metal plate thickness measurement process. (A) is a perspective view of a resistance metal plate or the like for explaining the protective film forming step, (b) is a plan view of the resistor metal plate or the like for explaining the protective film forming step, and (c) is a protective film forming step. FIG. 5 is an enlarged cross-sectional view of a resistance metal plate and the like (for example, an enlarged cross-sectional view taken along line BB in FIG. 5B). (A) is a perspective view of a resistance metal plate or the like for explaining the slit forming step, (b) is a plan view of the resistor metal plate or the like for explaining the slit forming step, and (c) is for explaining the slit forming step. FIG. 5 is an enlarged cross-sectional view of the resistance metal plate and the like (a cross-sectional enlarged view taken along the line CC in FIG. 5B). (A) is a perspective view of a resistance metal plate or the like for explaining the electrode plating film forming step, (b) is a plan view of the resistance metal plate or the like for explaining the electrode plating film forming step, and (c) is an electrode plating. FIG. 6 is an enlarged cross-sectional view of a resistive metal plate and the like for explaining the film forming process (cross-sectional enlarged view taken along the line DD in FIG. 5B). (A) is a perspective view of a resistance metal plate or the like for explaining the strip-shaped portion cutting step, (b) is a perspective view of the strip-shaped portion for explaining the strip-shaped portion cutting step and the strip-shaped portion cutting step, ( c) is a perspective view of a metal plate low resistance chip resistor (individual piece) for explaining a strip portion cutting step. It is a table | surface which shows each dimensional relationship of the metal plate low resistance chip resistor regarding the manufacturing method of the metal plate low resistance chip resistor which concerns on the embodiment of this invention. It is a flowchart which shows the manufacturing process of the metal plate low resistance chip resistor which concerns on the other embodiment of this invention. (A) is a perspective view of the strip | belt-shaped resistance metal plate for demonstrating a strip | belt-shaped resistance metal plate cutting process, (b) is a top view of the rectangular-shaped resistance metal plate for demonstrating a strip | belt-shaped resistance metal plate cutting process. (A) is a perspective view of a resistance metal plate for explaining the resistance metal plate thickness measurement step, (b) is a plan view of the resistance metal plate for explaining the resistance metal plate thickness measurement step, and (c) is a plan view of the resistance metal plate. It is a cross-sectional enlarged view (A1-A1 arrow cross-sectional enlarged view of (b)) of a resistance metal plate for demonstrating a resistance metal plate thickness measurement process. (A) is a perspective view of a resistance metal plate or the like for explaining the protective film forming step, (b) is a plan view of the resistor metal plate or the like for explaining the protective film forming step, and (c) is a protective film forming step. FIG. 5 is an enlarged cross-sectional view of a resistive metal plate and the like (for example, an enlarged cross-sectional view taken along line B1-B1 in (b)). (A) is a perspective view of a resistance metal plate or the like for explaining the strip-shaped cutting step, (b) is a perspective view of a strip-shaped portion for explaining the strip-shaped cutting step, and (c) is about the strip-shaped cutting step. FIG. 5 is an enlarged cross-sectional view of a strip-like portion for explanation (enlarged cross-sectional view taken along line C1-C1 in (b)). (A) is a perspective view of a strip-shaped portion for explaining the electrode plating film forming step, and (c) is an enlarged sectional view of the strip-shaped portion for explaining the electrode plating film forming step (D1-D1 in (a)). FIG. (A) is a perspective view of the strip-shaped part for demonstrating an individual piece cutting process, (b) is a perspective view of the metal plate low resistance chip resistor (individual piece) for demonstrating an individual piece cutting process. (A) is a perspective view showing the structure of the metal plate low resistance chip resistor, (b) is a plan view showing the structure of the metal plate low resistance chip resistor, (c) is the metal plate low resistance chip resistor. FIG. 6 is a cross-sectional view taken along line EE in (b) showing the structure. It is a flowchart which shows the manufacturing process of the conventional metal plate low resistance chip resistor. (A) is a perspective view of a resistive metal plate for explaining the slit forming step, (b) is a plan view of the resistive metal plate for explaining the slit forming step, and (c) is for explaining the slit forming step. FIG. 6 is an enlarged cross-sectional view of the resistance metal plate (an enlarged cross-sectional view taken along line FF in FIG. 5B). (A) is a perspective view of a resistance metal plate or the like for explaining the protective film forming step, (b) is a plan view of the resistor metal plate or the like for explaining the protective film forming step, and (c) is a protective film forming step. FIG. 6 is an enlarged cross-sectional view of a resistance metal plate and the like (a cross-sectional enlarged view taken along the line GG in FIG. 5B). It is a table | surface which shows each dimensional relationship of the metal plate low resistance chip resistor regarding the manufacturing method of the conventional metal plate low resistance chip resistor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

A method for manufacturing a chip resistor according to an embodiment of the present invention will be described with reference to FIGS. The structure of the metal plate low resistance chip resistor manufactured by the chip resistor manufacturing method of the present embodiment is as already described with reference to FIG. 16, and thus detailed description thereof is omitted here. To do.

In this embodiment, the metal plate low resistance chip resistor 1 having the structure as shown in FIG. 16 is cut into the strip-like resistance metal plate cutting step (step S11) shown in the process flowchart of FIG. 1 and the resistance metal plate thickness measurement. Step (Step S12), protective film formation step (Step S13), slit formation step (Step S14), electrode plating film formation step (Step S15), strip portion cutting step (Step S16), strip shape It manufactures by implementing a partial cutting process (step S17) in order.

Specifically, as shown in FIG. 2A, in the strip-shaped resistive metal plate cutting step (step S11), the strip-shaped resistive metal plate 2A conveyed in the direction of arrow J by the transport device (not shown) is converted into a laser. Then, cutting is performed at a cutting line position indicated by a one-dot chain line (virtual line) K by a cutting device such as a wire discharge or a cutting blade. The strip-shaped resistance metal plate 2A is made of a material such as FeCrAl-based, CuNi-based or CuMn-based, and in order to obtain a desired thickness, the material in the slab state is subjected to various processes, an annealing process and a rolling process. It is manufactured by repeating the process.

As a result of cutting the strip-shaped resistance metal plate 2A at the cutting position, a rectangular resistance metal plate 2B as shown in FIG. 2B is obtained. As shown in FIG. 2A, positioning marks 5 are provided on the strip-shaped resistive metal plate 2A at regular intervals in the length direction on both sides in the width direction. As shown in FIG. 2B, these positioning marks 5 are located on both sides in the width direction at the front end in the length direction of the rectangular resistance metal plate 2B. However, the positioning mark 5 is not limited to this, and may be only on one side in the width direction, or may be on the rear end portion or the center portion in the length direction of the resistance metal plate 2B.

As shown in FIGS. 3A to 3C, in the next resistance metal plate thickness measurement step (step S12), a plurality of (four in the illustrated example) protective films 3A, 3B (virtual lines (one point) Thicknesses T ₁ , T ₂ , T ₃ , T ₄ at respective positions in the width direction (left and right direction in FIG. 3B) of the resistance metal plate 2B forming (Omitted) Each position in the width direction of the resistance metal plate 2B where the plate thickness is measured is set with the positioning mark 5 as a reference.

In the illustrated example, each position in the width direction of the resistance metal plate 2B where the plate thickness is measured is set for each of the protective films 3A and 3B one by one. However, the present invention is not limited to this. For example, for each of the protective films 3A and 3B, the respective positions in the width direction of the resistance metal plate 2B where the thickness is measured are set at a plurality of locations, and the thickness of the resistance metal plate 2B measured at these plurality of locations. May be the thicknesses T ₁ , T ₂ , T ₃ , T ₄ at each position in the width direction of the resistive metal plate 2B.

As shown in FIGS. 4A to 4C, in the next protective film forming step (step S13), a plurality of (four in the illustrated example) protective films 3A and 3B are formed by screen printing or photolithography. By the method or the like, it is formed on the front surface 2B-1 and the back surface 2B-2 of the resistance metal plate 2B, respectively. These protective films 3A and 3b extend in the length direction of the resistance metal plate 2B and are parallel to each other in the width direction of the resistance metal plate 2B. The positions where the protective films 3A and 3B are formed are set with the positioning mark 5 as a reference.

In this protective film forming step, the widths of the protective films 3A and 3B (that is, the lengths of the protective films 3a and 3b in the chip resistor 1) L2 ₁ , L2 ₂ , L2 ₃ and L2 ₄ The resistance metal plate thickness is measured according to the thicknesses T ₁ , T ₂ , T ₃ , and T ₄ at the respective positions in the width direction of the resistance metal plate 2B measured in the resistance metal plate thickness measurement step (step S12). Specifically, the widths L2 ₁ , L2 ₂ , L2 ₃ , L2 ₄ of the protective films 3A, 3B are calculated based on the following equation (2). Equation (2) is a modification of Equation (1).

In equations (1) and (2), R is the resistance value (target resistance value) of the chip resistor 1, and L2 is the length of the protective films 3a and 3b in the chip resistor 1 (that is, the protective film 3a of the resistive metal plate 2). , 3b), W is the width (target value) of the chip resistor 1 (ie, the width of the resistive metal plate 2), T _n is the thickness of the resistive metal plate 2, and ρ is the resistive metal plate. 2 volume resistivity. That is, the resistance value R of the chip resistor 1 is the width W, length L2, and thickness _Tn (L2 / (W × _Tn )) of the portion of the resistive metal plate 2 covered with the protective films 3a and 3b. , Determined by the volume resistivity ρ of the resistive metal plate 2.

The resistance value R (target resistance value), the width W (target value) determined in the strip portion cutting step (step 17), and the volume resistivity ρ are known, and the thickness T _n (that is, the anti-metal plate 2B). The thicknesses T ₁ , T ₂ , T ₃ , and T ₄ ) at the respective positions in the width direction are also measured and known in the previous resistance metal plate thickness measurement step (step S12), and these values are used. From the above equation (2), the width of each protective film 3A, 3B according to the thickness T ₁ , T ₂ , T ₃ , T ₄ at each position in the width direction of the anti-metal plate 2B (that is, the chip resistor 1) L2 ₁ , L2 ₂ , L2 ₃ , and L2 ₄ can be calculated.

When the widths L2 ₁ , L2 ₂ , L2 ₃ , and L2 ₄ of the protective films 3A and 3B are calculated, screen patterns corresponding to these calculated values are set, and the screen printing method is performed based on the screen pattern. Thus, the protective film 3A, 3B is formed by printing the paste of the epoxy resin on the front surface 2B-1 and the back surface 2B-2 of the resistance metal plate 2B and baking the screen-printed paste. Of course, when using a photolithographic method or the like, a pattern corresponding to the calculated values of the widths L2 ₁ , L2 ₂ , L2 ₃ , and L2 ₄ of the protective films 3A and 3B is set, and the protective films 3A and 3B are set. Form.

As shown in FIGS. 5A to 5C, in the next slit forming step (step S14), a plurality of (six in the illustrated example) slits 6 are formed in the resistance metal plate 2B. These slits 6 extend in the length direction of the resistance metal plate 2B (vertical direction in FIG. 5B), and are adjacent protective films in the width direction of the resistance metal plate 2B (left and right direction in FIG. 5B). 3A and 3B (that is, between the protective films 3A and 3A on the front surface 2B-1 side and between the protective films 3B and 3B on the back surface 2B-2 side) and on both sides in the width direction of the resistive metal plate 2B It is formed outside 3A and 3B (that is, outside the protective film 3A on both sides in the width direction on the surface 2B-1 side and outside the protective film 3B on both sides in the width direction on the back surface 2B-2 side). The position where the slit 6 is formed is set with the positioning mark 5 as a reference. By forming such a plurality of slits 6, the resistance metal plate 2 </ b> B has a plurality of (four in the illustrated example) strip-like portions 7 extending in the length direction of the resistance metal plate 2 </ b> B and the plurality of strip-like shapes. It becomes the shape which has the connection part 8 which connects the both ends of the length direction (up-down direction of FIG.5 (b)) of the part 7 respectively. In the figure, L4 ₁ , L4 ₂ , L4 ₃ , L4 ₄ , and L4 ₅ are the widths of the slits 6, and L3 ₁ , L3 ₂ , L3 ₃ , and L3 ₄ are the widths of the resistance metal plate 2 B in the strip-shaped portion 7. (The length L3 of the resistance metal plate 2 in the chip resistor 1).

The slit 6 is formed on the front and back sides 2B- of the resistance metal plate 2B by a dry film exposed and developed so as to leave a portion corresponding to the connecting portion 8 and the strip-like portion 7 wider than the protective films 3A and 3B. 1 and 2B-2 including the protective films 3A and 3B are covered, and in this state, an etching solution suitable for each type (various materials) of the resistance metal plate 2B is applied to both the front and back surfaces 2B-1, 2B- of the resistance metal plate 2B. The resistance metal plate 2B is formed by etching with an etching method of spraying to 2. By forming the slit 6 by such an etching method, the side surface (surface on the slit 6 side) 2B-5 of the resistive metal plate 2B in the strip-shaped portion 7 becomes the front and back both surfaces 2B-1 and 2B-2 of the resistive metal plate 2B. It becomes a flat surface perpendicular to the rectangular shape, and the width L3 ₁ , L3 ₂ , L3 ₃ , L3 ₄ (the length L3 of the resistive metal plate 2 in the chip resistor 1) of the resistive metal plate 2B in the strip portion 7 is set with high accuracy. can do. The means for forming the slit 6 is not necessarily limited to the etching method, and means such as laser processing can also be used. In the illustrated example, the connecting portions 8 are formed at both ends of the strip-shaped portion 7 in the length direction. However, the present invention is not limited thereto, and the connecting portions 8 are formed only at one end in the length direction of the strip-shaped portion 7. May be.

As shown in FIGS. 6A to 6C, in the next electrode plating film forming step (step S15), the protective films 3A and 3B are not formed in each strip-shaped portion 7 and are exposed. Electrode plating films 4A and 4B are formed by electroplating on the surfaces of both end portions 2B-3 and 2B-4 in the width direction of the resistance metal plate 2B (left and right direction in FIG. 6C). At this time, a plating film 4C (shown in a perspective view of a one-dot chain line for convenience of explanation) is also formed on the peripheral edge portion of the resistance metal plate 2B such as the connecting portion 8. For example, a nickel plating film and a tin plating film are formed as the electrode plating films 4A and 4B. The electrode plating films 4A and 4B may be formed by forming nickel strike plating, copper plating, nickel plating, and tin plating film in this order.

As shown in FIGS. 7 (a) and 7 (b), in the next strip portion cutting step (step S16), the laser and wire discharge are performed at the cutting position M indicated by the alternate long and short dash line (virtual line). The strip portion 7 is cut from the connecting portion 8 by cutting with a cutting device such as a cutting blade. FIG. 7B shows an enlarged view of one of the plurality of strip-like portions 7 cut out from the connecting portion 8.

As shown in FIGS. 7B and 7C, in the next strip-shaped portion cutting step (step S17), the strip-shaped portion 7 is cut at a cutting position N indicated by a one-dot chain line (virtual line). A plurality of (in the illustrated example, 10) pieces are cut by a cutting device such as wire discharge or a cutting blade. Thus, the metal plate low resistance chip resistor 1 as shown in FIG. 7C is manufactured. That is, by cutting the strip-shaped portion 7 into a plurality of pieces, the resistance metal plate 2B in the strip-shaped portion 7, the protective films 3A and 3B, and the electrode plating films 4A and 4B are used to form the resistance metal in the chip resistor 1. A plate 2, protective films 3a and 3b, and electrode plating films 4a and 4b are formed, respectively.

The correspondence relationship between the dimensions of the strip-shaped portion 7 and the dimensions of the chip resistor 1 will be described. The width L1 of the resistive metal plate 2B and the electrode plating films 4B and 4B in the strip-shaped portion 7 corresponds to the total length L1 of the chip resistor 1. The width C of the electrode plating films 4A and 4B in the strip portion 7 corresponds to the length C of the electrode plating films 4a and 4b in the chip resistor 1, and the width L2 of the protective films 3A and 3B in the strip portion 7 Is equivalent to the length L2 of the protective films 3a, 3b in the chip resistor 1, and the width L3 of the resistive metal plate 2B in the strip-like portion 7 is equivalent to the length L3 of the resistive metal plate 2 in the chip resistor 1. .

The chip resistor manufacturing process including the resistance metal plate thickness measurement process as described above is performed on any of the rectangular resistance metal plates 2B sequentially cut from the strip-like resistance metal plate 2A. This is because the thickness variation may occur in the length direction of the strip-shaped resistance metal plate 2A. In this case, the thickness variation in the width direction is different for each resistance metal plate 2B. When there is almost no thickness variation in the length direction of the strip-shaped resistive metal plate 2A, the thickness measurement is performed only on the rectangular resistive metal plate 2B that is first cut from the strip-shaped resistive metal plate 2A. The protective film 3A is formed on the rectangular resistive metal plate 2B which is cut out from the strip-shaped resistive metal plate 2A on the second and subsequent widths. , 3B may be applied.

As described above, according to the method for manufacturing the metal plate low resistance chip resistor of the present embodiment, the chip resistor manufacturing method using the rectangular resistance metal plate 2B, the surface of the resistance metal plate 2B being used. A protective film forming step for forming a plurality of protective films 3A and 3B extending in the length direction of the resistive metal plate 2B in the width direction of the resistive metal plate 2B for each of 2B-1 and the back surface 2B-2 (step S13) And a slit 6 extending in the length direction of the resistive metal plate 2B between the protective films 3A and 3B adjacent in the width direction and outside the protective films 3A and 3B located on both sides in the width direction. By forming the resistance metal plate 2B on the metal plate 2B, the plurality of strip portions 7 having a width wider than the protective films 3A and 3B and extending in the length direction of the resistance metal plate 2B, and the plurality of strips The lengthwise ends of the shaped part 7 A slit forming step (step S14) for forming a connecting portion 8 to be connected to each other, and a width direction of the strip-like portion 7 where the protective films 3A and 3B are not formed and the resistance metal plate 2B is exposed. Electrode plating film forming step (step S15) for forming electrode plating films 4A and 4B on the surfaces of both end portions 2B-3 and 2B-4, and strip-shaped portion cutting off the strip-shaped portion 7 from the connecting portion 8 Since the chip resistor 1 is manufactured by sequentially performing the step (step S16) and the strip portion cutting step (step S17) for cutting the strip portion 7 into a plurality of pieces. The protective films 3A and 3B are formed before the slit 6 (that is, the strip-shaped portion 7).

For this reason, for example, even if the chip resistor 1 is required to be further downsized and the width L3 of the resistive metal plate 2B in the strip portion 7 is further reduced, the width of the resistive metal plate 2B in the strip portion 7 is reduced. The protective films 3A and 3B can be easily formed without being affected by L3. That is, it is easy to form the protective films 3A and 3B by screen printing or photolithography.

Further, the allowable range of adjustment of the width L2 of the protective films 3A and 3B (the length of the protective films 3a and 3b in the chip resistor 1) L2 can be increased. In the case of the dimension example of the chip resistor 1 as described above, a description will be given based on FIG. 8, for example, when the length L2 of the protective films 3a and 3b is set to 0.9 mm, the total length of the electrode plating films 4a and 4b. In the case where 2 × C is the longest 0.6 mm (= 2 × (0.2 + 0.1)) and the shortest 0.2 mm (= 2 × (0.2−0.1)), the chip resistor 1 The total length L1 is 1.5 mm and 1.1 mm, respectively. Therefore, the total length L1 of the chip resistor 1 may be set to 1.5 mm (= 1.6−0.1) which is the shortest allowable dimension. When the length L2 of the protective films 3a and 3b is set to 1.2 mm, the chip resistor 1 is used when the total length 2 × C of the electrode plating films 4a and 4b is 0.6 mm at the longest and 0.2 mm at the shortest. The total length L1 is 1.8 mm and 1.4 mm, respectively. Therefore, the total length L1 of the chip resistor 1 may be set in the range of 1.5 to 1.7 mm. When the length L2 of the protective films 3a and 3b is set to 1.5 mm, the chip resistor 1 is used when the total length 2 × C of the electrode plating films 4a and 4b is 0.6 mm at the longest and 0.2 mm at the shortest. The total length L1 is 2.1 mm and 1.7 mm, respectively. Therefore, the total length L1 of the chip resistor 1 may be set in a range of 1.7 mm which is the longest allowable dimension. Therefore, the adjustment allowable range of the length L2 of the protective films 3a and 3b is 0.6 mm, which is larger than the adjustment allowable range of 0.4 mm (see FIG. 20) in the conventional manufacturing method.

Moreover, according to the manufacturing method of the metal plate low resistance chip resistor of the present embodiment, the thicknesses T ₁ and T ₂ at the respective positions in the width direction of the resistance metal plate 2B forming the plurality of protective films 3A and 3B. , T ₃ and T ₄ are measured before the protective film forming step (step S13), and the resistance metal plate thickness measuring step (step S13) is performed. According to the thicknesses T ₁ , T ₂ , T ₃ , T ₄ at the respective positions in the width direction of the resistive metal plate 2B measured in the height measuring step (step S12), the respective protective films 3A, 3B Since the widths L2 ₁ , L2 ₂ , L2 ₃ , and L2 ₄ are set, the widths of the protective films 3A and 3B (in the chip resistor 1 in accordance with the thickness variation in the width direction of the resistive metal plate 2B). Adjusting the length of the protective films 3a, 3b) It can be. For this reason, variation in the resistance value of the chip resistor 1 due to variation in the thickness in the width direction of the resistive metal plate 2B can be reduced.

In the manufacturing method of the metal plate low resistance chip resistor described above, the rectangular resistive metal plate 2B is cut from the strip-shaped resistive metal plate 2A, and the protective films 3A and 3B are applied to the rectangular resistive metal plate 2B. After the slit 6 (strip-shaped portion 7) and the electrode plating films 4A and 4B are formed, the strip-shaped portion 7 is cut out, but the present invention is not necessarily limited thereto. That is, the rectangular resistive metal plate 2B is not cut, and the protective films 3A and 3B, the slit 6 (strip-shaped portion 7), and the electrode plating films 4A and 4B are formed on the strip-shaped resistive metal plate 2A. The strip portion 7 may be cut out.

A method for manufacturing a chip resistor according to another embodiment of the present invention will be described with reference to FIGS. The structure of the metal plate low resistance chip resistor manufactured by the chip resistor manufacturing method of this embodiment is as already described with reference to FIG. Is omitted.

In this other embodiment, the metal plate low resistance chip resistor 1 having the structure as shown in FIG. 16 is manufactured by the strip-like resistance metal plate cutting step (step S21) shown in the process flowchart of FIG. Measuring step (step S22), protective film forming step (step S23), strip cutting step (step S24), electrode plating film forming step (step S25), and individual piece cutting step (step S26). , Manufactured in order.

More specifically, as shown in FIG. 10A, in the strip-shaped resistive metal plate cutting step (step S21), the strip-shaped resistive metal plate 12A transported in the direction of arrow J1 by the transport device (not shown) is converted into a laser. Then, cutting is performed at a cutting line position indicated by a one-dot chain line (virtual line) K1 by a cutting device such as a wire discharge or a cutting blade. The strip-shaped resistance metal plate 12A is made of a material such as FeCrAl-based, CuNi-based or CuMn-based, and in order to obtain a desired thickness, the material in the slab state is subjected to various processes, an annealing process and a rolling process. It is manufactured by repeating the process.

As a result of cutting the strip-shaped resistance metal plate 12A at the cutting position, a rectangular resistance metal plate 12B as shown in FIG. 10B is obtained. As shown in FIG. 10A, positioning marks 15 are provided on the strip-shaped resistance metal plate 12A at regular intervals in the length direction on both sides in the width direction. As shown in FIG. 10B, these positioning marks 15 are located on both sides in the width direction at the front end portion in the length direction of the rectangular resistance metal plate 12B. However, this is not limiting, and the positioning mark 15 may be only on one side in the width direction, or may be on the rear end portion or the center portion of the resistance metal plate 12B in the length direction.

As shown in FIGS. 11A to 11C, in the next resistance metal plate thickness measurement step (step S22), a plurality (seven in the illustrated example) of protective films 13A and 13B (virtual lines (one point) Thickness T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , T ₆ , T at each position in the width direction (left and right direction in FIG. 11B) of the resistance metal plate 12B forming ₇ is measured by a plate thickness measuring device (not shown). Each position in the width direction of the resistance metal plate 12B where the plate thickness is measured is set with the positioning mark 15 as a reference.

In the illustrated example, each position in the width direction of the resistance metal plate 12B where the plate thickness is measured is set for each of the protective films 13A and 13B one by one. However, the present invention is not limited to this. For example, with respect to each of the protective films 13A and 13B, the respective positions in the width direction of the resistance metal plate 12B where the plate thickness is measured are set at a plurality of locations, and the thickness of the resistance metal plate 12B measured at these plurality of locations. _{May be} the thicknesses T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , T ₆ , T ₇ at each position in the width direction of the resistive metal plate 12B.

As shown in FIGS. 12A to 12C, in the next protective film forming step (step S23), a plurality of (seven in the illustrated example) protective films 13A and 13B are formed by screen printing or photolithography. By the method or the like, it is formed on the front surface 12B-1 and the back surface 12B-2 of the resistance metal plate 12B, respectively. These protective films 13A and 13b extend in the length direction of the resistance metal plate 12B and are parallel to each other in the width direction of the resistance metal plate 12B. The positions where the protective films 13A and 13B are formed are set with the positioning mark 15 as a reference.

In this protective film forming step, the widths of the protective films 13A and 13B (that is, the lengths of the protective films 3a and 3b in the chip resistor 1) L2 ₁ , L2 ₂ , L2 ₃ , L2 ₄ , L2 ₅ , L2 ₆ , L2 ₇ are the thicknesses T ₁ , T ₂ , T ₃ , T ₄ , T at each position in the width direction of the resistive metal plate 12B measured in the previous resistive metal plate thickness measurement step (step S22). _5, in response to T _6, T _7, sets. Specifically, the widths L2 ₁ , L2 ₂ , L2 ₃ , L2 ₄ , L2 ₅ , L2 ₆ , and L2 ₇ of the protective films 13A and 13B are calculated based on the following equation (4). Equation (4) is a modification of Equation (3).

In equations (3) and (4), R is the resistance value (target resistance value) of the chip resistor 1, and L2 is the length of the protective films 3a and 3b in the chip resistor 1 (that is, the protective film 3a of the resistive metal plate 2). , 3b), W is the width (target value) of the chip resistor 1 (ie, the width of the resistive metal plate 2), T _n is the thickness of the resistive metal plate 2, and ρ is the resistive metal plate. 2 volume resistivity. That is, the resistance value R of the chip resistor 1 is the width W, length L2, and thickness _Tn (L2 / (W × _Tn )) of the portion of the resistive metal plate 2 covered with the protective films 3a and 3b. , Determined by the volume resistivity ρ of the resistive metal plate 2.

The resistance value R (target resistance value), the width W (target value) determined in the piece cutting step (step 26), and the volume resistivity ρ are known, and the thickness T _n (that is, the resistance metal plate 12B) The thicknesses T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , T ₆ , T ₇ ) at the respective positions in the width direction are also measured and known in the previous resistance metal plate thickness measurement step (step S22). Therefore, using these values, the thicknesses T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , T ₆ , T ₇ at each position in the width direction of the anti-metal plate 12B are obtained from the above equation (4). The widths of the protective films 13A and 13B (that is, the lengths of the protective films 3a and 3b in the chip resistor 1) L2 ₁ , L2 ₂ , L2 ₃ , L2 ₄ , L2 ₅ , L2 ₆ and L2 ₇ are calculated. be able to.

When the widths L2 ₁ , L2 ₂ , L2 ₃ , L2 ₄ , L2 ₅ , L2 ₆ , and L2 ₇ of the protective films 13A and 13B are calculated, screen patterns are set according to these calculated values, and this screen pattern In accordance with the screen printing method, the epoxy resin paste is printed on the front surface 12B-1 and the back surface 12B-2 of the resistance metal plate 12B, and the screen-printed paste is baked to obtain each Protective films 13A and 13B are formed. Of course, when using a photolithography method or the like, patterns corresponding to the calculated values of the widths L2 ₁ , L2 ₂ , L2 ₃ , L2 ₄ , L2 ₅ , L2 ₆ , and L2 ₇ of the protective films 13A and 13B are set. Thus, the protective films 13A and 13B are formed.

As shown in FIGS. 13A to 13B, in the next strip-shaped cutting step (step S24), the resistance metal plate 12B is subjected to laser and wire discharge at a cutting position M1 indicated by a one-dot chain line (virtual line). By cutting with a cutting device such as a cutting blade, a plurality (seven in the illustrated example) of strip-shaped portions 17 are cut. FIG. 13B shows an enlarged view of one of the plurality of strip-shaped portions 17 cut from the resistance metal plate 12B, and FIG. 13C shows a cross section of the single strip-shaped portion 17. Is shown enlarged. L3 shown in FIG. 13B is the width of the resistive metal plate 12B in the strip-shaped portion 17 (the length L3 of the resistive metal plate 2 in the chip resistor 1), and L2 is the protective films 13A and 13B in the strip-shaped portion 17. (In the chip resistor 1, the length L2 of the protective films 3a and 3b).

As shown in FIG. 13A, the cutting position (cutting line) M1 extends in the length direction of the resistance metal plate 12B (vertical direction in FIG. 12B), and the width direction of the resistance metal plate 12B (FIG. 13). 12 (b) in the left-right direction), between the adjacent protective films 3A and 3B (that is, between the protective films 13A and 13A on the front surface 12B-1 side and between the protective films 13B and 13B on the back surface 12B-2 side), and the resistance The outer side of the protective films 13A and 13B located on both sides in the width direction of the metal plate 12B (that is, the outer side of the protective film 13A on both sides in the width direction on the front surface 12B-1 side and the protective films 13B on both sides in the width direction on the back surface 12B-2 side). Set to outside). These cutting positions (cutting lines) M1 are set on the basis of the positioning mark 15 so that the width L3 of the resistance metal plate 12B in the strip-shaped portion 17 becomes a predetermined value. The width L3 of the resistive metal plate 12B in the strip-shaped portion 17 is determined by a cutting allowance (ie, a laser beam width, a wire thickness, a cutting blade thickness, etc.) by a laser, wire discharge, or a cutting device such as a cutting blade. It can also be adjusted by appropriately adjusting the cutting position (width of cutting line M1).

As shown in FIG. 13B, FIG. 13C, FIG. 14A, and FIG. 14B, in the next electrode plating film forming step (step S25), the protective film 13A is formed in the strip portion 17. , 13B are not formed and are exposed to the surface of both end portions 12B-3, 12B-4 in the width direction (left-right direction in FIG. 13 (b)) of the exposed resistance metal plate 12B by electroplating. Electrode plating films 14A and 14B are formed. At this time, the plating films 14C and 14D are also formed at both ends in the length direction of the strip-shaped portion 17 where the protective films 13A and 13B are not formed. As the electrode plating films 14A and 14B, for example, a nickel plating film and a tin plating film are formed. Further, the electrode plating films 14A and 14B may be formed by forming nickel strike plating, copper plating, nickel plating, and tin plating film in this order.

As shown in FIG. 15 (a), in the next individual piece cutting step (step S26), the strip-like portion 17 is made of laser, wire discharge, cutting blade, etc. at a cutting position N1 indicated by a one-dot chain line (virtual line). A plurality of pieces (12 pieces in the illustrated example) are cut by a cutting device. Thus, the metal plate low resistance chip resistor 1 as shown in FIG. 15B is manufactured. That is, by cutting the strip-shaped portion 17 into a plurality of pieces, the resistance metal plate 12B, the protective films 13A and 13B, and the electrode plating films 14A and 14B in the strip-shaped portion 17 are used. A plate 2, protective films 3a and 3b, and electrode plating films 4a and 4b are formed, respectively.

The correspondence relationship between the dimensions of the strip-shaped portion 17 and the dimensions of the chip resistor 1 will be described. The width L1 of the resistive metal plate 12B and the electrode plating films 14B and 14B in the strip-shaped portion 17 corresponds to the total length L1 of the chip resistor 1. The width C of the electrode plating films 14A and 14B in the strip-shaped part 17 corresponds to the length C of the electrode plating films 4a and 4b in the chip resistor 1, and the width L2 of the protective films 13A and 13B in the strip-shaped part 17 Is equivalent to the length L2 of the protective films 3a and 3b in the chip resistor 1, and the width L3 of the resistive metal plate 12B in the strip-like portion 17 is equivalent to the length L3 of the resistive metal plate 2 in the chip resistor 1. .

The chip resistor manufacturing process including the resistance metal plate thickness measurement process as described above is performed on any of the rectangular resistance metal plates 12B sequentially cut from the strip-shaped resistance metal plate 12A. This is because the thickness variation may occur in the length direction of the strip-shaped resistance metal plate 12A, and in this case, the thickness variation in the width direction differs for each resistance metal plate 12B. When there is almost no thickness variation in the length direction of the strip-shaped resistive metal plate 12A, the thickness measurement is performed only on the rectangular resistive metal plate 12B that is first cut from the strip-shaped resistive metal plate 12A. The protective film 13A is formed to determine the widths of the protective films 13A and 13B, and the protective films 13A and 13B are formed on the rectangular resistive metal plate 12B cut from the strip-shaped resistive metal plate 12A on the second and subsequent sides. , 13B may be applied.

From the above, the same effect as that of the method of manufacturing the metal plate low resistance chip resistor of the above embodiment can be obtained in the method of manufacturing the metal plate low resistance chip resistor of the other embodiments.

That is, according to the manufacturing method of the metal plate low resistance chip resistor of the other embodiment, the manufacturing method of the chip resistor 1 using the rectangular resistance metal plate 12B, the surface of the resistance metal plate 12B A protective film forming step of forming a plurality of protective films 13A and 13B extending in the length direction of the resistive metal plate 12 in the width direction of the resistive metal plate 12B on each of the 12B-1 and the back surface 12B-2 (step S23). And a resistance at a cutting position M1 extending in the length direction of the resistive metal plate 12B between the protective films 13A and 13B adjacent in the width direction and outside the protective films 13A and 13B located on both sides in the width direction. By cutting the metal plate 12B, a strip-shaped cutting step (a step of cutting a plurality of strip-shaped portions 17 having a width wider than the protective films 13A and 13B and extending in the length direction of the resistance metal plate 12B). Electrode S24) and the surface of both end portions 12B-3 and 12B-4 in the width direction of the strip portion 17 where the protective metal plates 13A and 13B are not formed and the resistance metal plate 12B is exposed. Chip resistance is achieved by sequentially performing an electrode plating film forming step (step S25) for forming the plating films 14A and 14B and an individual piece cutting step (step S26) for cutting the strip portion 17 into a plurality of pieces. Since the container 1 is manufactured, the protective films 13A and 13B are formed before the strip portion 17 is cut out.

For this reason, for example, even if the chip resistor 1 is further reduced in size and the width L3 of the resistance metal plate 12B in the strip portion 17 is further reduced, the width of the resistance metal plate 12B in the strip portion 17 is reduced. The protective films 13A and 13B can be easily formed without being affected by L3. That is, it is easy to form the protective films 13A and 13B by screen printing or photolithography.

Also, the allowable range of adjustment of the width of the protective films 13A and 13B (the length of the protective films 3a and 3b in the chip resistor 1) L2 can be increased (see FIG. 8).

Further, according to the method of manufacturing the metal plate low resistance chip resistor of the other embodiment, the thickness T ₁ at each position in the width direction of the resistance metal plate 12B forming the plurality of protective films 13A and 13B, the _{T 2, T 3, T 4} , T 5, T 6, resistance metal to measure T ₇ plate thickness measuring step (step S22), and carried out before the protective film formation step (step S23), the protective film formation In the step (step S23), the thicknesses T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , T at each position in the width direction of the resistive metal plate 12B measured in the resistive metal plate thickness measuring step (step S22). _6, in response to T _7, because it and sets a plurality of protective films 13A, the width of each of the _{13B L2 1, L2 2, L2} 3, L2 4, L2 5, L2 6, L2 7, resistors The protective film 13A according to the thickness variation in the width direction of the metal plate 12B 13B the width (protection in the chip resistor 1 film 3a, the length of the 3b) can be adjusted. For this reason, the variation in the resistance value of the chip resistor 1 due to the variation in the thickness in the width direction of the resistance metal plate 12B can be reduced.

In the metal plate low-resistance chip resistor manufacturing method described above, the rectangular resistive metal plate 12B is cut from the strip-shaped resistive metal plate 12A, and the protective films 13A and 13B are applied to the rectangular resistive metal plate 12B. The strip-shaped portion 17 is cut out after forming the film, but the present invention is not necessarily limited thereto. That is, the rectangular resistance metal plate 12B is not cut out, and the strip-shaped portion 17 may be cut out after the protective films 13A and 13B are formed on the strip-like resistance metal plate 12A.

The present invention relates to a method of manufacturing a chip resistor using a resistance metal plate, and is particularly useful when applied to a case where the width of the resistance metal plate of the strip-shaped portion becomes very narrow in the manufacturing process of the chip resistor. is there.

1 metal plate low resistance chip resistor, 2 resistance metal plate, 2A strip-shaped resistance metal plate, 2B rectangular resistance metal plate, 2B-1 front surface, 2B-2 back surface, 2B-3, 2B-4 end, 2B -5 side, 2a front, 2a-1, 2a-2 end, 2b back, 2b-1, 2b-2 end, 2c, 2d end, 2e, 2f end, 3a, 3b protective film, 3A, 3B Protective film, 4a, 4b electrode plating film, 4A, 4B electrode plating film, 4C plating film, 5 positioning mark, 6 slit, 7 strip-shaped part, 8 connecting part, 12A strip-shaped resistive metal plate, 12B rectangular resistive metal Plate, 12B-1 front surface, 12B-2 back surface, 12B-3, 12B-4 edge, 14A, 14B electrode plating film, 14C 14D plated film 15 positioning mark, 17 the strip-shaped part

Claims (4)

1. A method of manufacturing a chip resistor using a rectangular or strip-shaped resistive metal plate,
   A protective film forming step of forming a plurality of protective films extending in the length direction of the resistive metal plate in the width direction of the resistive metal plate with respect to each of the front and back surfaces of the resistive metal plate;
   Forming a slit extending in the length direction of the resistive metal plate between the adjacent protective films in the width direction and outside the protective film located on both sides of the width direction in the resistive metal plate; The plurality of strip-shaped portions having a width wider than the protective film and extending in the length direction of the resistance metal plate, and both ends in the length direction of the plurality of strip-shaped portions, respectively. A slit forming step to form a connecting portion to be connected;
   An electrode plating film forming step for forming an electrode plating film on the surfaces of both end portions in the width direction of the strip-shaped part where the protective metal plate is not formed and the resistance metal plate is exposed;
   A strip-shaped portion cutting step of cutting the strip-shaped portion from the connecting portion;
   A strip-shaped portion cutting step for cutting the strip-shaped portion into a plurality of pieces,
   The manufacturing method of the metal plate low resistance chip resistor characterized by manufacturing the said chip resistor by implementing in order.
2. In the manufacturing method of the metal plate low resistance chip resistor of Claim 1,
   Conducting a resistance metal plate thickness measurement step of measuring the thickness at each position in the width direction of the resistance metal plate forming the plurality of protective films before the protective film formation step,
   In the protective film forming step, the width of each of the plurality of protective films is set according to the thickness at each position in the width direction of the resistive metal plate measured in the resistive metal plate thickness measuring step. A method of manufacturing a metal plate low resistance chip resistor.
3. A method of manufacturing a chip resistor using a rectangular or strip-shaped resistive metal plate,
   A protective film forming step of forming a plurality of protective films extending in the length direction of the resistive metal plate in the width direction of the resistive metal plate with respect to each of the front and back surfaces of the resistive metal plate;
   Cutting the resistive metal plate at a cutting position extending in the length direction of the resistive metal plate between the protective films adjacent in the width direction and outside the protective film located on both sides of the width direction. A strip-shaped cutting step of cutting a plurality of strip-shaped portions having a width wider than the protective film and extending in the length direction of the resistance metal plate;
   An electrode plating film forming step for forming an electrode plating film on the surfaces of both end portions in the width direction of the strip-shaped part where the protective metal plate is not formed and the resistance metal plate is exposed;
   An individual piece cutting step of cutting the strip-shaped portion into a plurality of pieces,
   The manufacturing method of the metal plate low resistance chip resistor characterized by manufacturing the said chip resistor by implementing in order.
4. In the manufacturing method of the metal plate low resistance chip resistor according to claim 3,
   Conducting a resistance metal plate thickness measurement step of measuring the thickness at each position in the width direction of the resistance metal plate forming the plurality of protective films before the protective film formation step,
   In the protective film forming step, the width of each of the plurality of protective films is set according to the thickness at each position in the width direction of the resistive metal plate measured in the resistive metal plate thickness measuring step. A method of manufacturing a metal plate low resistance chip resistor.

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