JP2009246147A - Method of manufacturing chip resistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a microsize chip resistor having a low resistance value and excellent TCR characteristics. <P>SOLUTION: The method of manufacturing the chip resistor includes the steps of: printing a pair of first upper-surface electrodes 13 at both ends of an upper surface of an insulating substrate 11 and then firing them; printing a first resistance body 14 so as to form a bridge between the pair of first upper-surface electrodes 13; printing a pair of second upper-surface electrodes 15 so that they are electrically connected to the first resistance body 14 and the pair of first upper-surface electrodes 13; and printing a second resistance body 16 covering a portion of the first resistance body 14, the second resistance body 16 being formed shorter than the first resistance body 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a chip resistor used in various electronic devices, and particularly to a method of manufacturing a micro-sized chip resistor having a low resistance value and good TCR characteristics.

  In recent years, with the miniaturization and high performance of electronic devices, there is an increasing demand for small-sized chip resistors having low resistance values and good TCR characteristics.

  As shown in FIG. 10, a conventional chip resistor of this type includes a resistor 2 formed on the upper surface of the insulating substrate 1 and both end portions of the upper surface of the insulating substrate 1 so as to partially overlap the resistor 2. A pair of upper surface electrodes 3, a protective layer 4 covering all of the resistor 2 and a part of the pair of upper surface electrodes 3, and formed on both end surfaces of the insulating substrate 1, and the pair of upper surface electrodes A pair of end face electrodes 5 electrically connected to the electrode 3 and a plating layer 6 covering the pair of end face electrodes 5 were formed.

For example, Patent Documents 1 to 4 are known as prior art document information relating to the invention of this application.
Japanese Patent Laid-Open No. 10-143501 Japanese Patent Laid-Open No. 9-21816 Japanese Utility Model Publication No. 56-78506 Japanese Utility Model Publication No. 6-62566

  In order to realize a low resistance and low TCR characteristic, the conventional chip resistor disclosed in Patent Document 1 forms a resistor 2 by screen printing and drying a copper nickel alloy paste, and thereafter The upper electrode 3 was formed by screen-printing and drying a copper paste or silver paste, and the resistor 2 and the upper electrode 3 were simultaneously fired.

  However, in the technique disclosed in Patent Document 1, when the resistor 2 and the upper surface electrode 3 are fired simultaneously, in a neutral atmosphere or a reducing atmosphere in order to suppress oxidation of the resistor 2 made of a copper nickel alloy. It was necessary to fire, and as a result, expensive equipment such as a nitrogen firing furnace was required.

  In Patent Document 2, the resistor 2 is composed of a resistor paste mainly composed of ruthenium oxide, the top electrode 3 is composed of a conductor paste mainly composed of silver or silver palladium alloy, and the resistor A technique is disclosed in which two and the upper surface electrode 3 are simultaneously fired in air so that they can be manufactured at a low manufacturing cost without using expensive equipment such as a nitrogen baking furnace.

  However, the resistance paste mainly composed of ruthenium oxide disclosed in Patent Document 2 has a higher resistance value than the resistance paste mainly composed of a copper-nickel alloy. It was difficult to obtain by printing once.

  Then, like the chip resistor described in Patent Document 3, two or more layers of the resistor 2 and the upper surface electrode 3 are stacked and printed, thereby increasing the thickness of the resistor 2 and the upper surface electrode 3 to increase resistance. Although it is conceivable to lower the value, in this case, when the chip resistor size becomes minute, the following problems occur.

  That is, when the upper surface electrode 3 is formed by screen printing after two or more layers of the resistor 2 are printed and dried, the upper surface electrode 3 has a large thickness in the dry state before firing the resistor 2. When the mask used for printing is brought into contact with the resistor 2, a gap corresponding to the thickness of the resistor 2 is formed between the insulating substrate 1 and the mask, and the upper surface electrode 3 is screen-printed due to this gap. In the case of forming with, the paste may bleed as shown in FIG. 11 and short-circuit with an adjacent element, which has been a cause of deterioration in manufacturing yield. In order to suppress this bleeding, a technique for narrowing the width of the upper surface electrode 3 compared to the resistor 2 is described in Patent Document 4. However, in the case of a chip resistor, when the size becomes small, especially the 0603 size is described. In the following cases, there is a limit to reducing the width of the upper surface electrode 3. For example, even if the width of the upper surface electrode 3 is slightly narrower than that of the resistor 2, the printing position of the upper surface electrode 3 is shifted. In some cases, it was difficult to completely suppress the bleeding.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to provide a method for manufacturing a micro-sized chip resistor having a low resistance value and good TCR characteristics.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, a first step is carried out by bridging the pair of first upper surface electrodes and printing the pair of first upper surface electrodes on both ends of the upper surface of the insulating substrate. Printing the resistor, a step of printing a pair of second upper surface electrodes so as to be electrically connected to the first resistor and the pair of first upper surface electrodes, and the first resistor And printing a second resistor covering a part of the first resistor, the second resistor is formed to have a length shorter than that of the first resistor, and the second upper surface electrode is formed of the second resistor. According to this manufacturing method, the length of the second resistor is formed shorter than the length of the first resistor, and the second upper surface electrode is formed on the second resistor. Since the second upper surface electrode is formed so as not to overlap the second resistor, the first upper surface electrode and the first resistor are The gap formed between the mask used for printing the second upper surface electrode and the first upper surface electrode is a portion corresponding to the thickness of the first resistor. The second upper surface electrode is formed by screen printing because there is only a gap between the first resistor and the second resistor. In this case, there is little possibility that the paste will spread and short-circuit with the adjacent element, and the manufacturing yield can be improved.

  According to a second aspect of the present invention, there is provided a step of printing and baking a pair of first upper surface electrodes on both end portions of the upper surface of the insulating substrate, and a first bridge so as to bridge the pair of first upper surface electrodes. A step of printing the resistor, a step of printing a second resistor covering a part of the first resistor, and after printing the second resistor, the pair of first upper surface electrodes, And a step of printing a pair of second upper surface electrodes so as to be electrically connected to the first resistor and the second resistor, and the length of the second resistor is the first resistor The second resistor is formed to be shorter than the length of the resistor, and the second resistor is formed so that an end thereof is located up to an overlapping portion between the first upper surface electrode and the first resistor, and further, the second upper surface electrode Is formed so as to overlap the second resistor. According to this manufacturing method, the length of the second resistor is set to the first resistor. When the second upper surface electrode is formed by screen printing so as to straddle the first resistor, the second resistor, and the first upper surface electrode, the length of the second upper surface electrode is reduced. The gap formed between the mask used for printing and the first upper surface electrode is only the gap corresponding to the thickness of the first resistor, and the mask used for printing the second upper surface electrode and the first resistor. The gap formed between the first resistor and the second resistor is only the gap corresponding to the thickness of the second resistor, and a steep step that occurs when the first resistor and the second resistor have the same shape. Therefore, when the second upper surface electrode is formed by screen printing, there is little possibility that the paste will spread and short-circuit with an adjacent element, and the manufacturing yield can be improved. In addition, since the second resistor is formed so that the end thereof is located up to the overlapping portion of the first upper surface electrode and the first resistor, the length of the second resistor is set to the first length. The length of the second resistor can be ensured as long as possible under the condition that it is shorter than the length of the resistor, and a low resistance value can be obtained by increasing the proportion of the thick portion of the resistor. It has an effect.

  According to the third aspect of the present invention, in particular, the angle formed by the plane formed in common with the one end of the first resistor and the one end of the second resistor and the upper surface of the insulating substrate and the first resistance The angle formed by the plane in common with the other end of the body and the other end of the second resistor and the upper surface of the insulating substrate is 15 degrees or less (not including 0). According to this manufacturing method, the angle formed by the flat surface in common with the one end of the first resistor and the one end of the second resistor and the upper surface of the insulating substrate, and the other end of the first resistor and the first resistor Since the angle between the plane in common contact with the other end of the resistor 2 and the upper surface of the insulating substrate is 15 degrees or less, the one end of the first resistor and the one end of the second resistor When the angle formed between the common plane and the upper surface of the insulating substrate is large and / or the other end of the first resistor and the second resistor A smooth step without causing a steep step between the first upper surface electrode and the second resistor, which occurs when the angle formed between the flat surface in common with the other end of the substrate and the upper surface of the insulating substrate is large. Thus, after printing the second resistor, the pair of first resistors, the second resistor, and the pair of first upper surface electrodes are electrically connected to each other. In the case where the second upper surface electrode is formed by screen printing, there is little possibility that the paste will spread and short-circuit with an adjacent element, so that the production yield can be improved.

  According to a fourth aspect of the present invention, in particular, the second upper surface electrode is formed by printing a silver palladium alloy paste, and the first resistor and the second resistor are formed more than the second upper surface electrode. This is formed by printing a silver-palladium alloy paste having a high palladium content, and further firing the first resistor, the second resistor, and the second upper surface electrode at the same time. For example, the first resistor and the second resistor are formed by printing a silver-palladium alloy paste having a palladium content ratio higher than that of the second upper surface electrode, and the palladium content ratio is high. Since the silver-palladium alloy paste has a low TCR and a stable property, the first resistor and the second resistor are formed by using this resistor paste, thereby reducing the TCR. A chip resistor can be obtained, and furthermore, since the first resistor, the second resistor, and the second upper surface electrode are fired simultaneously, the first resistor and the second resistor are heat-treated. This is performed only once at the time of simultaneous firing, whereby the silver component diffuses from the first upper surface electrode and the second upper surface electrode to the first resistor and the second resistor, so that the composition of silver and palladium is increased. Since the deterioration of the TCR due to the shift is also suppressed, it has an operational effect that a stable chip resistor having a lower TCR can be obtained.

  According to the fifth aspect of the present invention, the width of the second resistor is made narrower than that of the first resistor. According to this manufacturing method, the width of the second resistor is reduced. Since the width of the first resistor is smaller than the width of the first resistor, even when the mask position is slightly shifted in the width direction of the chip resistor when the second resistor is screen-printed, the influence on the resistance value is reduced. As a result, a chip resistor having a high resistance value accuracy can be obtained.

  As described above, in the method of manufacturing a chip resistor according to the present invention, since the length of the second resistor is formed shorter than the length of the first resistor, the second upper surface electrode is formed by screen printing. And the first resistor and the second resistor are formed by printing a silver-palladium alloy paste having a palladium content ratio higher than that of the second upper surface electrode. Since the first resistor, the second resistor, and the second upper surface electrode are fired at the same time, an excellent effect that a small-sized chip resistor with a low resistance value and good TCR characteristics can be obtained. It plays.

(Embodiment 1)
Hereinafter, the manufacturing method of the chip resistor according to the first, fourth, and fifth aspects of the present invention will be described with reference to the drawings using the first embodiment.

  FIG. 1 is a cross-sectional view of the chip resistor according to the first embodiment of the present invention. 11 is an insulating substrate, 12 is a connection electrode, 13 is a first upper surface electrode, 14 is a first resistor, and 15 is Second upper surface electrode, 16 is a second resistor, 17 is a pre-coated glass, 18 is a protective film, 19 is a conductor resin upper surface electrode, 20 is an end surface electrode, 21 is a copper plating layer, 22 is a nickel plating layer, and 23 is tin. It is a plating layer.

  2 (a) to (d), FIGS. 3 (a) to (d) and FIGS. 4 (a) to (d) are manufacturing process diagrams showing a manufacturing method of the chip resistor in the first embodiment of the present invention. Yes, the manufacturing method will be described below with reference to the manufacturing process diagram. 2A to 4C are cross-sectional views of the piece-like substrate, and FIGS. 2B to 4D are top views of the piece-like substrate. In the following description of the manufacturing method, the description will be made using this piece-like substrate. However, in the actual manufacturing process, a sheet-like substrate in which a large number of pieces of this piece-like substrate are connected vertically and horizontally. It is manufactured using an insulating substrate, and is divided into strips or individual pieces before the formation of an end face electrode described later.

  First, as shown in FIGS. 2 (a) and 2 (b), metal organic paste containing gold as a main component is screen-printed and fired on both ends of the upper surface of an insulating substrate 11 made of alumina having a purity of about 96%. First, the connection electrode 12 is formed by screen printing, and then a thick film conductive paste made of a silver palladium alloy having a palladium content of 1% or less is screen-printed and fired so as to overlap a part of the connection electrode 12. A top electrode 13 is formed. The connection electrode 12 is formed so as to straddle the primary dividing line corresponding to the short side of the insulating substrate 11, but the secondary dividing line corresponding to the long side of the insulating substrate 11 is formed not to straddle. is there. The first upper surface electrode 13 is formed so that the width thereof is narrower than the width of the connection electrode 12.

  Next, as shown in FIGS. 2C and 2D, a resistance paste made of a silver-palladium alloy having a palladium content ratio of 45 to 50% is screen-printed so as to bridge the pair of first upper surface electrodes 13. The first resistor 14 is formed by drying. The first resistor 14 is formed so that its width is narrower than the width of the first upper surface electrode 13.

  Next, as shown in FIGS. 3A and 3B, the palladium content ratio is 5 to 15% so as to be electrically connected to the first resistor 14 and the pair of first upper surface electrodes 13. The second upper surface electrode 15 is formed by screen-printing and drying a thick film conductive paste made of a silver-palladium alloy, and further, the first resistor 14 covers a part of the first resistor 14. The second resistor 16 is screen-printed using the same resistance paste. In this case, the length of the second resistor 16 is formed shorter than the length of the first resistor 14, and the second upper surface electrode 15 is formed so as not to overlap the second resistor 16. is there. The first resistor 14 and the second resistor 16 are formed by screen-printing a resistance paste made of a silver-palladium alloy having a palladium content ratio higher than that of the second upper surface electrode 15, and the first resistor The resistor 14, the second resistor 16, and the second upper surface electrode 15 are fired simultaneously with a peak temperature of 850 to 900 ° C. The second resistor 16 is formed so that the width thereof is narrower than the width of the first resistor 14, and the end portion thereof is formed between the first upper surface electrode 13 and the first resistor 14. It is formed so as to be located up to the overlapping portion. The second upper surface electrode 15 is formed to have the same width as the first upper surface electrode 13, but the second upper surface electrode 15 is formed so that the width thereof is narrower than the width of the first upper surface electrode 13. The paste may be prevented from spreading when the second upper surface electrode 15 is formed by screen printing.

  Next, as shown in FIGS. 3C and 3D, after the precoat glass 17 is formed so as to cover the entire second resistor 16, the resistance value is adjusted to a desired value as necessary. Then, trimming grooves (not shown) are formed in the first resistor 14, the second resistor 16, and the precoat glass 17, and then the first resistor 14, the second resistor 16, and the precoat glass 17 are attached. A protective film 18 made of epoxy resin, phenol resin or the like is formed so as to cover it.

  Next, as shown in FIGS. 4A and 4B, the conductor resin upper surface electrode 19 made of resin silver is cured with a profile having a peak temperature of 200 ° C. so as to overlap the connection electrode 12 at both ends of the insulating substrate 11. To form. The conductor resin upper surface electrode 19 may be formed before the protective film 18. In addition, the conductor resin upper surface electrode 19 is formed in a continuous rod shape so as to straddle the secondary division line. In order to stabilize the resistance value low, the conductor resin upper surface electrode 19 straddles the secondary division line. The copper plating layer described later may be formed in such an independent pattern so as to be in direct contact with the connection electrode 12.

  After forming the protective film 18 and the conductive resin upper surface electrode 19 in this manner, the end portions of the insulating substrate 11, the connection electrode 12, and the conductive resin upper surface electrode 19 are the same by dividing the sheet-shaped insulating substrate into strips. In this state, the end electrode 20 that is electrically connected to the connection electrode 12 and the conductive resin upper surface electrode 19 is formed from the back surface of the insulating substrate 11 using the mask sputtering method. This end face electrode 20 is composed of a first layer made of chromium and a second layer made of copper-nickel alloy, and the first layer made of chromium is for improving the adhesion to the insulating substrate 11. The second layer made of a copper-nickel alloy is formed for the purpose of improving the adhesion with a copper plating layer to be described later and lowering the resistance value.

  Finally, as shown in FIGS. 4C and 4D, a plating layer having a three-layer structure is formed on the surfaces of the end surface electrode 20, the conductive resin upper surface electrode 19 and the second upper surface electrode 15 using a barrel plating method. The chip resistor according to the first embodiment of the present invention can be obtained by forming 21, the nickel plating layer 22, and the tin plating layer 23 in this order.

  In the chip resistor according to the first embodiment of the present invention manufactured by the above manufacturing method, the length of the second resistor 16 is shorter than the length of the first resistor 14, and the second upper surface electrode 15 is formed. Is formed so as not to overlap the second resistor 16, the second upper surface electrode 15 is formed so as to straddle only the first resistor 14 and the first upper surface electrode 13. The gap formed between the mask used for screen printing of the second upper surface electrode 15 and the first upper surface electrode 13 is only the gap corresponding to the thickness of the first resistor 14, and the first resistor As the second upper surface electrode 15 is formed by screen printing, a steep step is not generated as is the case when the second resistor 16 and the second resistor 16 have the same shape. Element and short circuit Possibility less of that, in which the effect is obtained that can be improved manufacturing yields.

  In the first embodiment of the present invention, the first resistor 14 and the second resistor 16 are screen-printed with a resistance paste made of a silver-palladium alloy having a palladium content ratio higher than that of the second upper surface electrode 15. Since this silver palladium alloy paste having a high palladium content ratio has a low TCR and has a stable property, the first resistor 14 and the second resistor are formed using this paste. By forming 16, a chip resistor having a low TCR can be obtained, and the first resistor 14, the second resistor 16, and the second upper surface electrode 15 are fired at the same time. The first resistor 14 and the second resistor 16 are heat-treated only once at the time of simultaneous firing, so that the silver component is removed from the first upper surface electrode 13 and the second upper surface electrode 15 by the first heat treatment. The deterioration of the TCR due to the diffusion of the composition of silver and palladium due to diffusion to the resistor 14 and the second resistor 16 is suppressed, so that a stable chip resistor having a lower TCR can be obtained. An effect is obtained.

  In the first embodiment of the present invention, since the width of the second resistor 16 is made smaller than the width of the first resistor 14, when the second resistor 16 is screen-printed. Even when the position of the mask is slightly shifted in the width direction of the chip resistor, the influence on the resistance value is reduced, thereby obtaining an effect that a chip resistor with high resistance value accuracy can be obtained.

(Embodiment 2)
Hereinafter, the manufacturing method of the chip resistor according to the second to fifth aspects of the present invention will be described with reference to the drawings by using the second embodiment.

  FIG. 5 shows a cross-sectional view of the chip resistor according to the second embodiment of the present invention, in which 31 is an insulating substrate, 32 is a connection electrode, 33 is a first upper surface electrode, 34 is a first resistor, and 35 is The second resistor 36 is a plane in common contact with one end of the first resistor 34 and the one end of the second resistor 35, and 37 is the other end of the first resistor 34 and the second resistor. A plane in common contact with the other end of the body 35, 38 is a second upper surface electrode, 39 is pre-coated glass, 40 is a protective film, 41 is a conductor resin upper surface electrode, 42 is an end surface electrode, 43 is a copper plating layer, 44 is nickel A plating layer 45 is a tin plating layer.

  6 (a) to 6 (d), FIGS. 7 (a) to (d), FIGS. 8 (a) to (d) and FIGS. 9 (a) and 9 (b) are chip resistors according to the second embodiment of the present invention. The manufacturing method will be described below with reference to the manufacturing process diagram. 6A to 8C are cross-sectional views of the individual substrate, and FIGS. 6B to 8D are the cross-sectional views of FIGS. b) shows a top view of the individual substrate, and in the following description of the manufacturing method, this individual substrate will be used for explanation, but in the actual manufacturing process, this individual substrate is used. The substrate is manufactured using a sheet-like insulating substrate in which a large number of substrates are connected vertically and horizontally, and is divided into strips or individual pieces before the formation of the end face electrodes described later.

  First, as shown in FIGS. 6A and 6B, a metal organic paste mainly composed of gold is screen-printed and fired on both ends of the upper surface of an insulating substrate 31 made of alumina having a purity of about 96%. First, the connection electrode 32 is formed by screen printing, and then a thick film conductive paste made of a silver palladium alloy having a palladium content ratio of 1% or less is screen-printed and fired so as to overlap a part of the connection electrode 32. A top electrode 33 is formed. The connection electrode 32 is formed so as to straddle the primary dividing line corresponding to the short side of the insulating substrate 31, but the secondary dividing line corresponding to the long side of the insulating substrate 31 is formed so as not to straddle. is there. The first upper surface electrode 33 is formed so that its width is narrower than the width of the connection electrode 32.

  Next, as shown in FIGS. 6C and 6D, a resistance paste made of a silver palladium alloy having a palladium content ratio of 45 to 50% is screen-printed so as to bridge the pair of first upper surface electrodes 33. The first resistor 34 is formed by drying. The first resistor 34 is formed such that its width is narrower than the width of the first upper surface electrode 33.

  Next, as shown in FIGS. 7A and 7B, the same resistance paste as that of the first resistor 34 is screen-printed and dried so as to cover a part of the first resistor 34. A second resistor 35 is formed. Here, the length of the second resistor 35 is formed to be shorter than the length of the first resistor 34, and the end of the second resistor 35 is the first upper surface electrode 33 and the first resistor. It is formed so as to be located up to the overlapping portion with the body 34. Further, the second resistor 35 is formed so that its width is narrower than that of the first resistor 34. Furthermore, by controlling the position and thickness at which the second resistor 35 is formed, the plane 36 and the insulating substrate 31 that are in common contact with one end of the first resistor 34 and the one end of the second resistor 35 are controlled. And the angle formed by the insulating substrate 31 and the flat surface 37 that is in contact with the other end of the first resistor 34 and the other end of the second resistor 35 are both 15 degrees or less (0 Not included).

  Next, as shown in FIGS. 7C and 7D, the second upper surface electrode 33, the first resistor 34, and the second resistor 35 are electrically connected to each other, and the second The second upper surface electrode 38 is formed by screen printing a thick film conductive paste made of a silver palladium alloy having a palladium content ratio of 5 to 15% so as to overlap the resistor 35. Here, the second upper surface electrode 38 is formed by screen-printing a silver-palladium alloy paste having a lower palladium content ratio than the first resistor 34 and the second resistor 35, and further the first resistor 34, the 2nd resistor 35, and the 2nd upper surface electrode 38 are baked simultaneously with the profile of peak temperature 850-900 degreeC. The second upper surface electrode 38 is formed to have the same width as the first upper surface electrode 33, but the second upper surface electrode 38 is formed so that the width thereof is narrower than the width of the first upper surface electrode 33. Further, paste bleeding may be suppressed when the second upper surface electrode 38 is formed by screen printing.

  Next, as shown in FIGS. 8A and 8B, after the precoat glass 39 is formed so as to cover the second resistor 35, the first resistance is adjusted as necessary in order to adjust the resistance value to a desired value. A trimming groove (not shown) is formed in the first resistor 34, the second resistor 35 and the precoat glass 39, and then the first resistor 34, the second resistor 35 and the precoat glass 39 are covered. A protective film 40 made of an epoxy resin, a phenol resin or the like is formed.

  Next, as shown in FIGS. 8C and 8D, the conductor resin upper surface electrode 41 made of resin silver is cured with a profile having a peak temperature of 200 ° C. so as to overlap the connection electrode 32 at both ends of the insulating substrate 31. To form. The conductor resin upper surface electrode 41 may be formed prior to the protective film 40. In addition, the conductor resin upper surface electrode 41 is formed in a continuous rod shape so as to straddle the secondary dividing line. In order to stabilize the resistance value low, the conductor resin upper surface electrode 41 straddles the secondary dividing line. The copper plating layer described later may be formed in such an independent pattern so as to be in direct contact with the connection electrode 32.

  After forming the protective film 40 and the conductor resin upper surface electrode 41 in this manner, the end portions of the insulating substrate 31, the connection electrode 32, and the conductor resin upper surface electrode 41 are the same by dividing the sheet-like insulating substrate into strips. In this state, the end surface electrode 42 that is electrically connected to the connection electrode 32 and the conductive resin upper surface electrode 41 is formed from the back surface of the insulating substrate 31 by using a mask sputtering method. The end face electrode 42 is composed of a first layer made of chromium and a second layer made of copper-nickel alloy, and the first layer made of chromium is for improving the adhesion to the insulating substrate 31. The second layer made of a copper-nickel alloy is formed for the purpose of improving the adhesion with a copper plating layer to be described later and lowering the resistance value.

  Finally, as shown in FIGS. 9A and 9B, a plating layer having a three-layer structure is formed on the surfaces of the end face electrode 42, the conductor resin upper surface electrode 41, and the second upper surface electrode 38 using a barrel plating method. 43, the nickel plating layer 44, and the tin plating layer 45 are formed in this order, whereby the chip resistor according to the second embodiment of the present invention is obtained.

  In the chip resistor according to the second embodiment of the present invention manufactured by the above manufacturing method, the length of the second resistor 35 is shorter than the length of the first resistor 34. When the electrode 38 is formed by screen printing so as to straddle the first resistor 34, the second resistor 35, and the first upper surface electrode 33, a mask used for screen printing of the second upper surface electrode 38 and the first upper surface electrode The gap formed between the first resistor 34 and the first resistor 34 is only the gap corresponding to the thickness of the first resistor 34 and between the mask used for screen printing of the second upper surface electrode 38 and the first resistor 34. The gap that occurs is a gap corresponding to the thickness of the second resistor 35, and a steep step that occurs when the first resistor 34 and the second resistor 35 have the same shape is generated. Because it becomes a gentle step, When forming the 2 upper electrode 38 by screen printing, the possibility that the paste is short and adjacent elements blurred less, in which can be improved manufacturing yields.

  In the second embodiment of the present invention, the second resistor 35 is formed so that the end thereof is located up to the overlapping portion of the first upper surface electrode 33 and the first resistor 34. In the condition that the length of the second resistor 35 is shorter than the length of the first resistor 34, the length of the second resistor 35 can be secured as long as possible, and the thickness of the resistor is thick. As the ratio increases, a low resistance value can be obtained.

  In the second embodiment of the present invention, the angle formed by the flat surface 36 in common with one end of the first resistor 34 and the one end of the second resistor 35 and the upper surface of the insulating substrate 31 and The angles formed by the flat surface 37 in common contact with the other end of the first resistor 34 and the other end of the second resistor 35 and the upper surface of the insulating substrate 31 are both 15 degrees or less (not including 0). When the angle formed by the flat surface 36 in common contact with the one end of the first resistor 34 and the one end of the second resistor 35 and the upper surface of the insulating substrate 31 is greater than 15 degrees. And / or such that it occurs when the angle formed between the upper surface of the insulating substrate 31 and the flat surface 37 in common contact with the other end of the first resistor 34 and the other end of the second resistor 35 is greater than 15 degrees. A steep step between the first upper surface electrode 33 and the second resistor 35 occurs. Thus, after the second resistor 35 is printed, the first resistor 34, the second resistor 35, and the pair of first upper surface electrodes 33 are electrically connected to each other. When the pair of second upper surface electrodes 38 are formed so as to be connected by screen printing, there is little possibility that the paste will spread and short-circuit with an adjacent element, and the manufacturing yield can be improved.

  Further, in the second embodiment of the present invention, the first resistor 34 and the second resistor 35 are screen-printed with a resistance paste made of a silver-palladium alloy having a palladium content ratio higher than that of the second upper surface electrode 38. Since the resistance paste made of a silver palladium alloy having a high palladium content ratio has a low TCR and has a stable property, the first resistor 34 and the first resistor 34 are formed using this resistance paste. By forming the second resistor 35, a chip resistor having a low TCR can be obtained, and the first resistor 34, the second resistor 35, and the second upper surface electrode 38 are fired simultaneously. Therefore, the first resistor 34 and the second resistor 35 are heat-treated only once at the time of simultaneous firing, whereby the first upper surface electrode 33 and the second upper surface 35 Since the silver component is diffused from the pole 38 to the first resistor 34 and the second resistor 35 and the composition of silver and palladium is deviated, deterioration of TCR is also suppressed. Therefore, a stable chip having a lower TCR. A resistor is obtained.

  In the second embodiment of the present invention, since the width of the second resistor 35 is narrower than the width of the first resistor 34, a mask is used when the second resistor 35 is screen-printed. Even if the position is slightly deviated in the width direction of the chip resistor, the influence on the resistance value is reduced, whereby a chip resistor with high resistance value accuracy can be obtained.

  The chip resistor manufacturing method according to the present invention has an effect that it is possible to suppress the bleeding of the paste when the second upper surface electrode is formed by screen printing, and the TCR characteristic is particularly good at a low resistance value. It becomes useful when applied to a chip resistor of a very small size.

Sectional drawing of the chip resistor in Embodiment 1 of this invention (A)-(d) Manufacturing process figure which shows the manufacturing method of the chip resistor (A)-(d) Manufacturing process figure which shows the manufacturing method of the chip resistor (A)-(d) Manufacturing process figure which shows the manufacturing method of the chip resistor Sectional drawing of the chip resistor in Embodiment 2 of this invention (A)-(d) Manufacturing process figure which shows the manufacturing method of the chip resistor (A)-(d) Manufacturing process figure which shows the manufacturing method of the chip resistor (A)-(d) Manufacturing process figure which shows the manufacturing method of the chip resistor (A) (b) Manufacturing process figure which shows the manufacturing method of the chip resistor Cross-sectional view of a conventional chip resistor The figure which showed the bleeding of the upper surface electrode of the conventional chip resistor

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Insulating substrate 13 1st upper surface electrode 14 1st resistor 15 2nd upper surface electrode 16 2nd resistor 31 Insulating substrate 33 1st upper surface electrode 34 1st resistor 35 2nd resistor 36 1st resistance A plane in common contact with one end of the body and one end of the second resistor 37 A plane in common contact with the other end of the first resistor and the other end of the second resistor 38 Second upper surface electrode

Claims (5)

A step of printing and firing a pair of first upper surface electrodes on both ends of the upper surface of the insulating substrate, a step of printing a first resistor so as to bridge the pair of first upper surface electrodes, and the first Printing a pair of second upper surface electrodes so as to be electrically connected to the resistor and the pair of first upper surface electrodes, and printing a second resistor covering a part of the first resistor The second resistor is formed to have a length shorter than that of the first resistor, and the second upper surface electrode is formed so as not to overlap the second resistor. Manufacturing method of chip resistor. A step of printing and firing a pair of first upper surface electrodes on both ends of the upper surface of the insulating substrate, a step of printing a first resistor so as to bridge the pair of first upper surface electrodes, and the first A step of printing a second resistor covering a part of the resistor, and after printing the second resistor, the pair of first upper surface electrodes, the first resistor, and the second resistor Printing a pair of second upper surface electrodes so as to be electrically connected to each other, the second resistor has a length shorter than that of the first resistor, and the first resistor The second resistor is formed so that the end portion is located up to the overlapping portion of the first upper surface electrode and the first resistor, and further, the second upper surface electrode is formed so as to overlap the second resistor. Of manufacturing a chip resistor. An angle formed by a plane in common contact with one end of the first resistor and one end of the second resistor and the upper surface of the insulating substrate, and the other end of the first resistor and the other end of the second resistor 3. The method of manufacturing a chip resistor according to claim 2, wherein an angle formed by a plane in common with the portion and an upper surface of the insulating substrate is 15 degrees or less (not including 0). The second upper surface electrode is formed by printing a silver palladium alloy paste, and the first resistor and the second resistor are printed with a silver palladium alloy paste having a higher palladium content ratio than the second upper surface electrode. 3. The method of manufacturing a chip resistor according to claim 1, wherein the first resistor, the second resistor, and the second upper surface electrode are simultaneously fired. 3. The method of manufacturing a chip resistor according to claim 1, wherein the width of the second resistor is made narrower than the width of the first resistor.

Images