JP2006024767A - Manufacturing method of chip resistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of chip resistors, whereby their side-surface electrodes can be formed accurately, stably, and at the same time, with the formations of their end-surface electrodes. <P>SOLUTION: The manufacturing method of chip resistors has a process of preparing a large-sized substrate 21 having formed dividing grooves A for dividing it into strip-form substrates, and having formed dividing grooves B for dividing it into piece-form substrates; a process of forming on the large-sized substrate top-surface electrodes 12a and resistors 13, connected respectively with the top-surface electrodes; a process of forming protective films 15, 16 for covering therewith the resistors; a process for so dividing the large-sized substrate along the dividing grooves A so as to form the strip-form substrates 22; and a process for so performing the applications of sputtering onto end surfaces 11a of the strip-form substrates which are exposed to the external by divisions performed along the dividing grooves A as to deposit metal films on the end surfaces of each strip-form substrate and on the inside surfaces of its grooves B, and as to form thereby end-surface electrodes 12c and side-surface electrodes 12d. Preferably, the size of each side-surface electrode 12d is controlled by its sputtering time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a chip resistor, and more particularly, to a method of manufacturing a micro-sized chip resistor with improved mountability on a printed circuit board.

  The chip resistor is provided with electrodes at both ends on the upper surface side of a rectangular insulating substrate such as alumina, a resistor is disposed between the electrodes, the resistor is covered with a protective film, and both ends of the rectangular insulating substrate are covered. Electrodes connected to the upper surface electrode are provided on the upper and lower surfaces and the end surface. The size of the chip resistor tends to be finer year by year. For example, the length × width is 1.6 mm × 0.8 mm, 1.0 mm × 0.5 mm, 0.6 mm × 0.3 mm, etc. It tends to be miniaturized.

When a chip resistor is mounted on a printed circuit board at a high density, the back side electrode (main surface) of the chip resistor is not fixed by solder connection, and the side surface of the chip resistor is fixed by solder connection to the land of the printed circuit board. In other words, so-called side surface mounting may occur. For this reason, it has been proposed to provide an electrode on the side surface of the chip resistor to cope with so-called side surface mounting (see Patent Document 1).
Japanese Patent Laid-Open No. 5-13201

  By the way, in order to cope with so-called side mounting, it is necessary to accurately form a sufficiently large electrode at a position corresponding to the upper and lower electrodes on the side surface of the chip resistor. However, the method proposed in the above publication has a problem that it is not sufficient to form a sufficiently large electrode with high accuracy and a good yield with a simple manufacturing process.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a chip resistor manufacturing method capable of forming a side electrode with high accuracy and stability simultaneously with the formation of an end face electrode.

  The manufacturing method of the chip resistor according to the present invention is to prepare a large substrate on which a divided groove A divided into strips and a divided groove B divided into individual pieces are formed, and the upper substrate is connected to the large substrate. The resistor is formed, a protective film covering the resistor is formed, the large substrate is divided along the dividing groove A to form a strip-shaped substrate, and exposed by dividing along the dividing groove A. Sputtering is performed on the end surface of the strip-shaped substrate, and a metal film is deposited on the end surface of the strip-shaped substrate and the inside of the dividing groove B to form a side electrode together with the end surface electrode.

  Here, the ratio of the total value of the depths of the dividing grooves B formed on both surfaces of the large substrate with respect to the thickness of the large substrate is preferably 1/2 to 1/3. The size of the electrode is preferably controlled by the sputtering time.

  According to this invention, the end surface of the strip-shaped substrate is sputtered, the metal film is deposited inside the end surface of the strip-shaped substrate and the dividing groove B, and the side surface electrode is formed together with the end surface electrode. Can be controlled by the sputtering time. For this reason, a side electrode can be formed accurately and stably simultaneously with the formation of the end face electrode. And since the metal film by sputtering is very thin, when dividing a strip-shaped board | substrate along the division | segmentation groove | channel B, troubles, such as becoming difficult to break, are not produced. That is, an electrode having a sufficient size as a side electrode can be formed with high accuracy, a simple manufacturing process, and a good yield.

  In general, according to the present invention, even in the case of so-called side surface mounting, a chip resistor having good mountability can be manufactured with a simple manufacturing process and a good yield.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a configuration example of a chip resistor of the present invention, and FIG. 2 shows a cross-sectional configuration along its longitudinal direction. In addition, in each figure, the same code | symbol is attached | subjected to the member or element which has the same effect | action or function, and the overlapping description is abbreviate | omitted.

  As shown in FIGS. 1 and 2, a chip resistor 10 according to the manufacturing method of the present invention includes electrodes 12a and 12a at both ends on the upper surface side of a rectangular insulating substrate 11 such as alumina, and electrodes 12a and 12a at both ends. A thick film resistor 13 made of ruthenium oxide or the like is disposed in between. The resistor 13 is covered and protected by a glass coat 15 and an overcoat (resin coat) 16.

  The both ends of the insulating substrate 11 are provided with electrodes 12 and 12 including the upper surface electrode 12a, the lower surface electrode 12b, the end surface electrode 12c, the side surface electrode 12d, the plating electrode 12e covering these, and the like. Usually, the lower surface electrode 12b side is fixed to the land pattern of the printed board by solder connection, whereby the chip resistor 10 is mounted on the printed board. The top electrode 12a and the bottom electrode 12b are formed by patterning a metal material paste such as Ag / Pd by screen printing and baking. The end face electrode 12c and the side face electrode 12d are formed of a metal film obtained by sputtering Ni or the like. In so-called side mounting, the side electrode 12d side is fixed to the land pattern of the printed circuit board by soldering.

  The dimension a in FIG. 1 indicates the thickness of the chip resistor, the dimension b indicates the width of the chip resistor, and the dimension c indicates the length of the chip resistor. The dimension d represents the distance between the side electrodes 12d, 12d extending from the upper surface side and the back surface side of the chip resistor. The thickness a of the chip resistor is 80 to 100% with respect to the width b, that is, the thickness a and the width b of the chip resistor are approximately the same size.

  Further, in this chip resistor 10, the side electrode 12d is sufficiently large and formed with high accuracy. Therefore, even if the side electrode 12d side is fixed to the land pattern by solder connection, sufficient mounting strength is ensured.

  Next, a manufacturing method of the chip resistor of the present invention will be described with reference to FIG. First, as shown in FIG. 3A, a large-sized large-sized substrate 21 in which a divided groove A for dividing the large substrate 21 into strips and a divided groove B for dividing the strips into individual pieces are formed. Prepare. The division grooves A and B are provided symmetrically at the same position on the front and back surfaces of the large substrate 21 using a laser.

  Here, the ratio of the total value of the depths f of the dividing grooves B formed on both surfaces of the large substrate 21 to the thickness a of the large substrate 21 is preferably set to 1/2 to 1/3. The depth f of the dividing groove B closely affects the depth (stretching distance in the thickness direction) of the side electrode 12d (see FIG. 1). That is, in order to increase the depth of the side electrode 12d and ensure a sufficient area of the side electrode 12d, it is preferable to make the dividing groove B deeper. However, if the depth f of the dividing groove B is excessively increased, the strength of the large-sized substrate (or the strip-shaped substrate after the division) is reduced, and it becomes easy to break during the manufacturing process, causing problems such as generation of defective products. From this balance, the ratio of the total value of the depths f of the dividing grooves B as described above to the thickness a is obtained.

  Next, as shown in FIG. 3B, the upper surface electrode 12a and the lower surface electrode 12b are formed. This is formed by using a thick film conductive material paste such as Ag / Pd, forming a pattern by screen printing, and firing the pattern. The screen printing process is performed twice for the front surface side and the back surface side of the large insulating substrate 21, but the baking process can be performed once.

  Next, as shown in FIG. 3C, the resistor 13 connected between the upper surface electrodes 12a and 12a is formed. The resistor 13 is formed by patterning a thick film resistor paste such as ruthenium oxide by screen printing and baking at a high temperature.

  Next, as shown in FIG. 3D, a glass coat 15 that covers the resistor 13 is formed. The glass coat 15 is formed by patterning a paste containing a glass material by screen printing and baking. Thereafter, if necessary, a probe is brought into contact with the electrodes 12a and 12a, and laser trimming is performed while measuring the resistance value of the resistor, thereby adjusting the resistance value as a resistor.

  Next, as shown in FIG. 3E, an overcoat (resin coat) 16 that further covers the glass coat 15 is formed. The overcoat 16 is formed by patterning a resin material paste such as epoxy by screen printing and heating and curing. The overcoat 16 serves as an exterior protective film that covers and protects the resistor 13. At this stage, the processing on the large substrate 21 is completed.

  Next, as shown in FIG. 3 (f), the large substrate 21 is divided along the dividing grooves A to form strip-shaped substrates 22. That is, the strip-shaped substrate 22 corresponds to one row of the large-sized substrate 21.

  As shown in FIG. 4A, the strip-shaped substrate 22 is in a state where the end surface 11 a of the insulating substrate 11 is exposed along the dividing groove A. And the division | segmentation groove | channel B mentioned above is arrange | positioned between each chip | tip division located in a line. Here, the total depth from the front and back sides of the division grooves B is about 1/2 to 1/3 of the thickness a of the insulating substrate as described above.

  Next, as shown in FIG. 4B, sputtering is performed on the end surface 11a of the strip-shaped substrate exposed by the dividing groove A, and a metal thin film is formed in the end surface 11a, the upper and lower surfaces 11b and 11c, and the dividing groove B of the strip-shaped substrate. To precipitate. This sputtering is performed from the direction perpendicular to the end surface 11a of the strip-shaped substrate, and a very thin sputtering thin film is deposited on the end surface 11a, the upper and lower surfaces 11b, 11c, and the wall surfaces in the dividing grooves B. Sputtering uses a nickel target, for example, and deposits a nickel thin film. Sputtering is performed twice in the vertical direction with respect to the left and right end faces 11a of the strip-shaped substrate 22.

  At the time of sputtering, the sputtered particles are incident on the end face from the vertical direction (X direction) as shown in FIG. 3C, and adhere to the end face 11a of the insulating substrate, and wrap around the upper and lower surfaces at both ends of the insulating substrate. It adheres to 11b and 11c, and further adheres to the wall surface 11d in the dividing groove B. Then, the formation region L of the sputtering thin film on the upper and lower surfaces 11b and 11c of the insulating substrate and the wall surface 11d in the dividing groove B depends on the sputtering time t as shown in FIG. That is, when the sputtering time is short, the sputtering thin film formation region L becomes small, and when the sputtering time is long, the sputtering thin film formation region L becomes large.

  In this embodiment, for example, by setting the sputtering time to about 20 to 30 minutes, a sufficiently large side electrode 12d can be formed as shown in FIG. Therefore, by forming the side electrode 12d made of a sputtering thin film on the wall surface 11d in the dividing groove B by sputtering, the size can be controlled by the sputtering time, so that the side electrode 12d having a constant size can be very stably formed. Can be formed.

  After forming the electrodes 12a, 12b, 12c, and 12d by sputtering, the electrodes 12a, 12b, 12c, and 12d are divided along the dividing grooves B into chips (chips). When dividing along the dividing groove B, since only a very thin sputtering thin film is deposited on the wall surface in the groove, there is no hindrance to the division such as difficulty in cracking. And after dividing | segmenting into a piece, the chip resistor 10 provided with the plating electrode 12e on the exposed surface of the upper surface electrode 12a, the lower surface electrode 12b, the end surface electrode 12c, and the side surface electrode 12d by giving nickel plating and solder (tin) plating. Is completed. Thereafter, the chip resistor 10 is shipped through processes such as stamping and inspection.

  As described above, since the side electrode 12d is accurately and sufficiently sized in the chip resistor 10, a stable mounting strength can be obtained even when the side mounting is performed when the printed board is mounted. .

  Next, another embodiment of the present invention will be described. FIG. 5A shows a deformation pattern 12k of the lower surface electrode 12b such as Ag / Pd. That is, in the above embodiment, the lower surface electrode 12b is formed so as to be separated with the dividing groove B interposed therebetween as shown in FIG. On the other hand, the lower electrode pattern 12k shown in FIG. 5A is continuously formed across the dividing groove B. An opening 31 is provided in the vicinity of the intersection of the dividing groove A and the dividing groove B, and a notch 32 is provided in a portion straddling the dividing groove B.

  Here, for example, the thickness of the upper surface electrode is 8 to 10 μm, while the lower surface electrode has a thickness of 5 to 7 μm. Thereby, the coating 12k (see FIG. 5B) of the Ag / Pd paste can be formed on the wall surface 11d in the lower surface side dividing groove B of the insulating substrate 11 by pressing during screen printing. The coating 12k is fired simultaneously with the firing of the upper and lower surface electrodes 12a and 12b to form a metal coating. Except for the bottom electrode pattern 12k, the other steps are the same as in the above embodiment.

  Accordingly, in the chip resistor 10k in this modified embodiment, as shown in FIG. 5B, the side electrode 12d on the upper electrode side is formed of the sputtering thin film as described above, and the side electrode 12k on the lower electrode side is What is pushed into the dividing groove B of the thick film electrode paste together with the formation of the lower surface electrode is used.

  As shown in FIG. 5A, the lower electrode pattern 12k has an opening 31 in the vicinity of the intersection with the dividing grooves A and B. Therefore, when the lower electrode pattern 12k is divided into strip-shaped substrates, the end face 11d of the insulating substrate 11 is used. The lower portions (corner portions) 11d ′ at the left and right ends of the left side are exposed. However, in the above-described sputtering step (see FIG. 4B), the side electrode 12d and the end surface electrode 12c are formed by the sputtering thin film, and further, the wraparound to the upper and lower electrodes is formed. At this time, the exposed lower portions (corner portions) 11 d ′ at both the left and right ends of the end surface 11 d of the insulating substrate 11 are also covered with the sputtering thin film, as shown in FIG.

  For this reason, even if the opening 31 is provided in the lower surface electrode 12k, this portion is later covered with the sputtering thin film, so there is no problem. By providing the opening 31 and the notch 32, the dividing grooves A and B are provided. The division along the line becomes easy, and the workability of the division is improved.

  In addition, when forming a side electrode by pouring Ag / Pd paste in the division | segmentation groove | channel B at the time of screen printing, it is necessary to control the flow amount of the paste into the division | segmentation groove | channel B appropriately. For this purpose, it is necessary to highly control the fluidity of the paste itself and the temperature of the paste during screen printing. Further, since the paste is baked in the dividing groove B to become a solid metal electrode, when dividing into individual pieces along the dividing groove B, the electrode portion is equally divided into each side electrode forming surface of the chip. There is also the problem that it is difficult. Further, when the electrode paste is poured into the side electrode forming region in the dividing groove B, the paste may be transmitted through the dividing groove by a so-called capillary phenomenon, and the upper surface electrodes 12a and 12a may be short-circuited.

  The above problems are considered to occur particularly when the chip size is reduced (for example, the so-called 1005 size (1.0 mm × 0.5 mm) or less), but the side electrode is formed by the above-described sputtering thin film. In the manufacturing method to be performed, problems caused by forming the side electrodes by pouring the metal material paste do not occur at all.

  In addition, although one Embodiment of this invention was described so far, it cannot be overemphasized that this invention is not limited to the above-mentioned embodiment, and may be implemented with a different form within the range of the technical idea.

  In particular, in the above-described embodiment, the thick film type chip resistor has been described. However, it is needless to say that the thin film type and other types of chip resistors can be similarly applied. Further, the gist of the present invention can be similarly applied not only to the chip resistor but also to a micro-sized chip component having substantially the same width and thickness.

It is a figure which shows embodiment of the chip resistor which concerns on this invention, and is a perspective view which shows the whole structure. It is sectional drawing along the length direction of the said chip resistor. It is process drawing explaining the manufacturing method of the said chip resistor. It is various explanatory drawings about the process of sputtering in the manufacturing process of the said chip resistor. It is various explanatory drawing which shows other embodiment of the chip resistor which concerns on this invention.

Explanation of symbols

10, 10k Chip resistor 11 Rectangular insulating substrate 12a Upper surface electrode 12b Lower surface electrode 12c End surface electrode 12d Side electrode 12e Plating electrode 13 Thick film resistor 14 Trimming groove 15 Glass coat 16 Overcoat 21 Large substrate 22 Strip-shaped substrate 31 Opening 32 Notch A, B Dividing groove

Claims (3)

Preparing a large-sized substrate in which a dividing groove A divided into strips and a dividing groove B divided into individual pieces are formed,
Forming a top electrode and a resistor connected thereto on the large substrate;
Forming a protective film covering the resistor;
A large substrate is divided along the dividing groove A to form a strip-shaped substrate,
Sputtering is performed on the end surface of the strip-shaped substrate exposed by dividing along the dividing groove A, and a metal film is deposited on the end surface of the strip-shaped substrate and the inside of the dividing groove B, thereby forming a side electrode together with the end surface electrode. A manufacturing method of a chip resistor characterized by the above.   2. The chip according to claim 1, wherein a ratio of a total value of the depths of the divided grooves B formed on both surfaces of the large substrate to a thickness of the large substrate is 1/2 to 1/3. Manufacturing method of resistors.   2. The method of manufacturing a chip resistor according to claim 1, wherein the size of the side electrode is controlled by the sputtering time.

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