JP2002231505A - Chip resistor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip resistor which can be mounted on a printed circuit board even in either surface or back face mounting case based on either Tp(taping), or bulk mounting method, and prevent burrs and chipping from occurring in an insulating board or a front and a rear electrode film along dividing slits in a dividing process and its manufacturing method. SOLUTION: The chip resistor is equipped with back electrode films 2, front electrode film lower layers 3, a resistor film 4, an undercoat film 5, a trimming groove 6, an overcoat film 7, and front electrode film upper layers 10. End face electrode films 8 are formed through a sputtering method so as to cover the lateral end faces of an insulating board 1 and to be partially superposed on the back electrode films 2 and front electrode upper layers 10. An electrode plating film 9 covers the back electrode films 2, the front electrode film upper layers 10, and the end face electrode films 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip resistor formed by dividing an insulating substrate on which a resistor film is arranged, and a method of manufacturing the chip resistor.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and spread of portable terminals and the like, the supply of chip type resistors having extremely small dimensions has been demanded. When adopting and mounting this extremely small chip-type resistor on the circuit board of small electronic devices, the parts and equipment manufacturers work together to increase the efficiency of mounting and ensure the reliability of solder joints. It is desired to do.

On the other hand, a method of manufacturing the chip-type resistor in a part maker or the like is formed by, for example, the following procedure. That is, first, an insulating substrate (made of porcelain containing 96% or more alumina) is prepared on both the front and back surfaces, and is screen-printed with a metal glaze (Ag or Ag / Pd-based glaze). 850
C. to form a back electrode having a thickness of 8 to 12 .mu.m. This back surface electrode is formed apart from the secondary direction split slip.

Next, a metal glaze (Ag.
Screen printing with Pd-based glaze)
Baking is performed at 50 ° C. to form a front electrode film having a film pressure of 8 to 12 μm. The firing at this time may be performed simultaneously with the firing for forming the back electrode. This front electrode film is formed apart from the secondary direction split slip. Subsequently, both ends of a RuO 2 -based glaze resistor film are placed (screen printed) between a pair of front electrode films, and then fired at 850 ° C.
An undercoat film is formed on the resistor film.

[0005] This undercoat film is screen-printed with lead borosilicate glass across a split in the secondary direction,
This was fired at about 600 ° C. to form a film having a thickness of 8 to 12 μm. Then, a trimming groove for adjusting the resistance value is formed by the laser method from the undercoat film. Subsequently, screen division printing of lead borosilicate glass is performed on the undercoat film,
Firing at ℃ to form an overcoat film. Subsequently, a primary break is made in a strip shape along the divided slit in the primary direction of the insulating substrate.

Further, printing is performed with an Ag-based or Ag / Pd-based glaze, and baked at 600 ° C.
Then, an end face electrode film having a thickness of m is formed and then divided into individual chips by a secondary break, and a Ni plating film and a Sn plating film or a Sn · Pb plating film are formed as electrode plating films.

FIG. 4 is a schematic view showing an embodiment of a manufacturing process of a chip-type resistor according to the prior art. This chip-type resistor is formed into a rectangular chip by dividing an insulating substrate by dividing slits formed in a primary direction and a secondary direction. 4 (a) to 4 (i) show the steps of manufacturing a chip resistor as viewed on a chip-by-chip basis. First, as shown in FIG. 4 (a), a region separated by a predetermined distance from both front and rear ends of the insulating substrate 1 so as to be located on both left and right ends on the back side of the insulating substrate 1 partitioned into a rectangular shape, The back electrode film 2 is formed in a region separated from the secondary sliding slit. On the other hand, as shown in FIG. 4 (b), a region between the front and rear ends of the insulating substrate 1 and a position separated by a predetermined distance from the front and rear ends of the insulating substrate 1 so as to be located at the left and right ends of the front surface of the insulating substrate 1.
To form Then, as shown in FIG. 4 (c), the lower surface electrode layers 3 at the left and right end portions are connected to each other by a resistor film 4 so as to overlap a part thereof, and the resistor film 4 is further connected to the lower layer. The front and rear ends of the insulating substrate 1 are covered with the undercoat film 5 as shown in FIG. Further, a trimming groove 6 is cut out from above the undercoat film 5 to adjust the resistance value of the resistor film 4 as shown in FIG. 4D, and a part of the insulating substrate 1 is removed. As shown in FIG. 4E, the undercoat film 5 and the trimming groove 6 are covered with an overcoat film 7 up to the front and rear ends.

Next, the left and right end surfaces of the insulating substrate 1 are covered and the back electrode film 2 is covered with the left and right end surfaces.
4 (f) so as to overlap with part of the front electrode film 3.
And forming an end face electrode film 8 as shown in FIG.
Finally, as shown in FIGS. 4 (h) and 4 (i), the back electrode film 2, the front electrode film 3 and the end face electrode film 8 are covered with an electrode plating film 9, so that a chip type resistor is formed. To complete. FIG. 5 is a front sectional view of a chip-type resistor manufactured through such a process.

[0009]

However, in the above-described method of manufacturing a chip-type resistor, a part of the back electrode film 2 and the front electrode film 3 made of a thick metal glaze is formed.
Since the end face electrode 8 of a thick metal glaze partially overlaps, a step is formed in these overlapped portions, and when soldering and mounting on a circuit board land, the influence of the wetting stress at the time of solder melting is applied. However, there is a problem that tombstones are easily generated. Further, since the end face electrode 8 is formed of a thick metal glaze, the breakability at the time of breaking along the split slit in the secondary direction of the insulating substrate is poor, and the thickness of the end face electrode is large and uneven. Therefore, the stability of the finished dimensional accuracy in the longitudinal direction of the chip resistor is poor, and the breakability of the division and the poor dimensional accuracy are remarkable in a small chip resistor.

Further, since the back electrode film 2 is formed so as to be separated from the secondary division slit, the distance between the back electrode film 2 and the secondary division slit cannot be kept uniform, and either the left or right As a result, the self-alignment effect at the time of soldering to the circuit board land cannot be expected, and there is a problem that the semiconductor device is mounted in a state of being displaced with respect to the circuit board land. Further, as a product, the surface of the overcoat film 7 protrudes from the surface of the front electrode,
Further, since the mounting on the circuit board is limited to the supply by Tp (taping) for single-side mounting only on the back electrode film side, there is a problem that mounting efficiency on the circuit board is low.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to enable mounting on a circuit board and supply by Tp or bulk, regardless of the state of the front side or the back side, respectively. It is possible to suppress the occurrence of burrs and chipping of the insulating substrate and front and back electrode films at the time of division in the divided sliding, and it is also possible to respond to the stabilization and miniaturization of the finishing accuracy of the length and width dimensions of the chip resistor. An object of the present invention is to provide a chip-type resistor capable of suppressing the tombstone phenomenon and having a good self-alignment effect, and a method of manufacturing the same.

[0012]

To achieve the above object,
The chip-type resistor according to the first aspect of the present invention is formed at the left and right ends and at the front and rear ends of the insulating substrate so as to be located at the left and right ends on the back side of the rectangularly partitioned insulating substrate. A back electrode film, a lower layer of the front electrode film formed in a region from the front and rear ends of the insulating substrate to positions at predetermined distances from the front and rear ends of the insulating substrate so as to be located at both left and right ends of the front side of the insulating substrate; The lower layers are connected to each other, a resistor film covering a part thereof, an undercoat film covering the resistor film, and a resistor film formed on the undercoat film to adjust the resistance value of the resistor film. A trimming groove, a part of which extends to the front and rear ends of the insulating substrate, an overcoat film that covers the undercoat film and the trimming groove, and an upper layer of the front electrode film covering the front and rear ends of the insulating substrate on the lower surface of the front electrode film. With An end face electrode film is formed on the left and right end faces by a sputtering method so as to cover the left and right end faces of the insulating substrate, or to cover the left and right end faces and overlap each part of the back electrode film and the front electrode film upper layer, The back electrode film,
The upper layer of the front electrode film and the end face electrode film are covered with an electrode plating film.

Further, in the chip type resistor according to the present invention, the back electrode film may be a metal glaze-based film having a thickness of 8 μm or less, or a silver resin-based conductive film having a thickness of 10 μm or less. A metal glaze-based conductive film having a film thickness of 8 μm or less, or a silver resin-based conductive film having a film thickness of 10 μm or less; Is a resin-based or glass-based film.

According to a third aspect of the present invention, there is provided a method of manufacturing a chip-type resistor, wherein a divided slit in a primary direction and a secondary direction is formed on a front surface and a rear surface of an insulating substrate so as to be divided into a rectangular shape. A back electrode film forming step of forming a back electrode film over the split in the primary direction and the secondary direction,
On the surface of the insulating substrate, straddle the split in the primary direction, and form a lower layer of the front electrode film so as to be separated from the split in the secondary direction,
Connecting the lower layer of the front electrode film to each other, forming a resistor film covering a part thereof; and forming an undercoat film so as to cover the resistor film, A trimming groove engraving step of engraving a trimming groove for adjusting the resistance value of the resistor film from above the undercoat film, and a secondary direction of the insulating substrate so as to cover the undercoat film and the trimming groove. An overcoat film forming step of forming an overcoat film so as to avoid a part of the divisional slit and to straddle a part of the divisional slip in the secondary direction of the insulating substrate; A surface electrode film upper layer forming step of forming a surface electrode film upper layer so as to straddle the split in the secondary direction of the substrate, and the insulating substrate is subjected to mechanical enemy stress along the split in the primary direction. An insulating substrate dividing step of dividing the insulating substrate into strips by using a sputtering method so as to cover the left and right end surfaces of the insulating substrate, or to cover the left and right end surfaces and overlap the back electrode film and the upper surface of the front electrode film. Performing an end face electrode film forming step of forming an end face electrode film by a construction method, and a chip-shaped dividing step of dividing the insulating substrate into chips using mechanical stress along a secondary sliding slit in a secondary direction. In the electroplating film forming step, an electrode plating film is formed so as to cover the back electrode film, the upper layer of the front electrode film, and the end face electrode film.

According to a fourth aspect of the present invention, in the method of manufacturing a chip-type resistor, the step of forming the back electrode film includes the step of forming the resin-type overcoat film followed by the step of forming an Ag resin. Forming the back electrode film.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail. First, a method for manufacturing a resistor chip according to the present invention will be described. First, an insulating substrate containing 96% or more of alumina and having splits in the primary and secondary directions on its front and back surfaces is prepared. On the back surface, the split slits in the primary and secondary directions are straddled. Screen printing is performed with a resinate of Au, Ag, or Pt, and baked at about 850 ° C. to form a back electrode having a thickness of several thousand ·, or Ag across a split in the primary and secondary directions.
Alternatively, screen printing is performed with an Ag / Pd glaze, which is baked at about 850 ° C. to form a back electrode having a thickness of 4 to 8 μm. Here, since the film thickness is controlled, even in the screen printing across the divided slits in the primary direction and the secondary direction, division at the time of the primary break of the insulating substrate becomes easy, and burrs and chipping of the divided surface are suppressed. In addition, the electrode film surface used for soldering can be widely used, the solder bonding area is large, and the self-alignment effect can be exhibited. Further, the accuracy of the division finish by the primary break is improved, and the accuracy in the width direction of the resistor is improved, which contributes to downsizing. Alternatively, the back electrode may be screen-printed with Ag resin so as to straddle the divided slits in the primary direction and the secondary direction, and cured at about 200 ° C. to have a film thickness of 5 to 10 μm. Next, print with Ag / Pd glaze,
By baking at about 850 ° C., a surface electrode film lower layer having a thickness of 8 to 12 μm is formed. The surface electrode film has a two-layer structure, the lower layer of the surface electrode film is formed so as to straddle the split in the primary direction and to be separated from the split slit in the secondary direction. By printing on the lower layer of the electrode film so as to straddle the splits in the primary and secondary directions, the upper layer of the front electrode film can be flush with or slightly higher than the surface of the overcoat film. Implementation becomes possible. The primary divided slits are located at the left and right ends of the insulating substrate divided into rectangles, and the secondary divided slips are located at the front and rear ends.

Next, screen printing is performed with a RuO ₂ -based glaze between the lower layers of the pair of front electrode films, and the resultant is fired at about 850 ° C. to form a resistor film. Screen printing of lead glass or screen printing across the split slits in the secondary direction,
By baking at 00 ° C., an undercoat film having a thickness of 8 to 12 μm is formed. Subsequently, trimming for resistance value adjustment is performed by a laser method from above the undercoat film, and the undercoat film is covered with an epoxy-based paint so as to avoid a part of the secondary slit in the secondary direction. After performing the screen printing as described above, it is cured at about 200 ° C. to form an overcoat film. As another overcoat film, lead borosilicate glass may be screen-printed and fired at about 600 ° C.

Subsequently, when the above-mentioned epoxy-based paint is used as the overcoat film, the epoxy-based paint is formed so as to overlap the lower layer of the front electrode film formed as described above and to straddle the split in the secondary direction. Screen printing with an Ag resin is performed and cured at about 200 ° C. to form an upper layer of the front electrode film having a thickness of 5 to 10 μm. On the other hand, when lead borosilicate glass was used as the overcoat film, the upper layer of the front electrode film was made of Ag.
System or an Ag / Pd-based glaze, screen printing is performed over the lower layer of the front electrode film so as to straddle the split in the secondary direction, and is baked at 600 ° C. to obtain a film thickness of 8 to 1
An upper layer of the front electrode film of 2 μm is formed.

After the formation of the upper layer of the front electrode film, if necessary, the A
g-containing epoxy resin paint is screen-printed, cured at about 200 ° C. to form a back electrode film having a thickness of 5 to 10 μm, and further screen-printed with a masking resist. A break occurs in a strip shape along the divided slit in the primary direction of the substrate. Then, a Cr thin film and a Ni thin film having a thickness of several thousand 数 are formed by a sputtering method so as to cover the end face of the insulating substrate or to cover the end face and partially overlap the upper layer of the front electrode film and the back electrode film.
A film is formed, the masking resist is removed, the insulating substrate is broken by a secondary sliding slit, divided into individual chips, and finally a Ni plating film and a Sn-based plating or Sn · Pb plating film are formed. By applying it as an electrode plating film, a chip-type resistor can be obtained.

Since the thickness of the upper layer of the front electrode film is controlled, even if the printing is performed across the split in the secondary direction, the insulating substrate can be easily split at the primary break.
Burrs and chips on the divided surface can be suppressed. Further, the electrode film to be used for soldering can be widely used, the bonding area can be widened, and the self-alignment effect can be contributed. Further, the accuracy of the division finish in the primary break is improved, and the accuracy in the width direction of the resistor is improved, which contributes to downsizing.

Next, the chip resistor according to the present invention viewed from a chip unit and a manufacturing process thereof will be described with reference to FIGS. 1 (a) to 1 (j). First, as shown in FIG. 1 (a), the insulating substrate 1 is positioned at the left and right ends and the front and rear ends of the insulating substrate 1 so as to be located on the right and left ends on the back side of the rectangularly divided insulating substrate 1, A back electrode film 2 is formed so as to straddle the divided slits in the primary direction and the secondary direction, and on both sides of the insulating substrate 1 so as to be located at the left and right ends on the front side of the insulating substrate 1. 1B, a surface electrode film lower layer 3 as shown in FIG. Then, as shown in FIG. 1C, the lower layer 3 of the front electrode film at the left and right ends is connected to each other by a resistor film 4, and the resistor film 4 is further connected by an undercoat film 5 in FIG. Cover as shown in). Further, a trimming groove 6 as shown in FIG. 1D is cut out from above the undercoat film 5 in order to adjust the resistance value of the resistor film 4, and as shown in FIG. The undercoat film 5 and the trimming groove 6 are covered with an overcoat film 7 so as to partially avoid the front and rear ends of the insulating substrate 1.

Further, as shown in FIG. 1F, the front electrode film lower layer 3 is covered with the front electrode film upper layer 10 to the left and right ends and the front and rear ends of the insulating substrate 1, and the left and right end faces of the insulating substrate 1 are covered. 1 (g) or 1 (h) so as to cover the left and right end faces and overlap the back electrode film 2 and part of the front electrode film upper layer 10 as shown in FIG. A film 8 is formed, and finally, as shown in FIG. 1 (i) or (j), the back electrode film 2,
The upper electrode layer 10 and the end face electrode film 8 are coated with the electrode plating film 9.
To form a chip resistor. FIG. 2 is a front sectional view of the chip resistor manufactured through the above steps.

Accordingly, in the chip resistor manufactured in this manner, the end face electrode film 8 as a sputtered film superimposed on a part of the back electrode film 2 and a part of the front electrode film upper layer 10 is formed by each of these electrode films. The occurrence of uneven steps is suppressed, and especially in the case of chip resistors having minute dimensions, the circuit board 1
When the solder is melted with the upper land, the occurrence of the tombstone phenomenon (tip standing) caused by the wetting stress of the solder can be suppressed. Further, since the thickness of the end face electrode film 9 is small, the dimensional accuracy in the length direction of the resistor is improved, which can contribute to downsizing.

Also, an overcoat that avoids a part of the split slip in the secondary break (resin or glass, a combination of the upper layer of the front electrode film and the overcoat film, and a combination of the back electrode film and the overcoat film)
Is formed, plating growth in the secondary break direction can be prevented during formation of the electrode plating film, and burrs and chipping of the overcoat film can be suppressed.

FIG. 3 shows the division finish at the time of the primary break and the secondary break when formed of metal glaze and / or Ag resin in the combination of printing of the upper electrode layer 10 and printing of the rear electrode film 2. The results are shown. Here, the nominal length of the chip resistor is 1.6 m
m, a sample having a nominal width of 0.8 mm was prepared as a sample, and the finished finish at the time of the primary break and the secondary break was visually inspected using a magnifying glass with a magnification of 10 for 100 factors. Pass / fail was determined. According to this, it is understood that the present example sufficiently satisfies the preferable range. In this embodiment, the chip-type resistor has a nominal length dimension of 1.6 mm and a nominal width dimension of 0.8 mm. However, the chip resistor is reduced in size to have various nominal dimensions other than the nominal dimensions. It can also be applied to chip type resistors.

[0026]

As described above, according to the present invention, the circuit board can be mounted on either the front side or the back side of the chip-type resistor, the supply can be made by either Tp or bulk, and the resistance can be increased. It contributes to the promotion of standardization and productivity improvement for equipment manufacturers. In addition, the burrs and chipping of the insulating substrate, the front and back electrode films and the coating film and the coating film at the time of the break in the primary direction and the secondary direction are suppressed, and the division accuracy is improved. The effect of stabilizing the finishing accuracy in the direction and enabling downsizing can be obtained. In addition, since the area of the front and back electrode films can be increased and flattened without steps, the occurrence of tombstones can be suppressed and a self-alignment effect can be expected.

Further, the uniformity of the thickness of the region of the front and back electrode films can be ensured, the self-alignment effect can be exhibited, and the effect of ensuring the flatness can suppress the occurrence of the tombstone phenomenon. . Furthermore, in each manufacturing process, the flow in the supply chute of the chip-type resistor is smoothed, and the chip-type resistor from the cavity in the Tp supply system is easily attracted and taken out by the nozzle of the mounting machine. Can be

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a manufacturing process of a chip-type resistor according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the chip resistor shown in FIG.

FIG. 3 is an explanatory diagram showing the results of division of an insulating substrate having an upper layer of a front electrode film and a back electrode film in the present invention.

FIG. 4 is an explanatory view showing a manufacturing process of a conventional chip-type resistor.

FIG. 5 is a longitudinal sectional view showing a conventional chip-type resistor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Back electrode film 3 Lower layer of front electrode film 4 Resistor film 5 Undercoat film 6 Trimming groove 7 Overcoat film 8 Edge electrode film 9 Electrode plating film 10 Upper layer of front electrode film

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuki Hirano 955-1 Naie, Naie-cho, Sorachi-gun, Hokkaido F-term (reference) in Kamaya Electric Co., Ltd. CC18 DA01 TA11 TB02 5E033 AA01 BB02 BC01 BE02 BE04 BH02

Claims (4)

[Claims] 1. A back electrode film formed at left and right ends and front and rear ends of an insulating substrate so as to be located at left and right ends on the back side of an insulating substrate partitioned into a rectangular shape. The lower surface electrode layer formed in the region from the front and rear ends of the insulating substrate to a position separated by a predetermined distance from each of the front and rear ends of the insulating substrate so as to be located at both left and right ends of the front surface of the insulating substrate, and the lower surface of the front electrode film are connected to each other. A resistor film covering a part of the resistor film, an undercoat film covering the resistor film, a trimming groove engraved from above the undercoat film for adjusting a resistance value of the resistor film, and a part of the insulating film; To the front and rear ends of the substrate, the overcoat film covering the undercoat film and the trimming groove, and on the lower surface of the front electrode film, the upper surface of the front electrode film covering the front and rear ends of the insulating substrate, and the left and right end faces of the insulating substrate. To cover Or an end face electrode film formed by a sputtering method so as to cover the left and right end faces and overlap with each part of the back electrode film and the upper surface layer of the front electrode film, and the back electrode film, the upper surface layer of the front electrode film and the end face electrode film. A chip-type resistor comprising: a covering electrode plating film. 2. The front electrode, wherein the back electrode film is a metal glaze-based film having a thickness of 8 μm or less, a silver resin-based conductive film having a thickness of 10 μm or less, or a metal-organic conductive film. The upper layer is a metal glaze-based conductive film having a thickness of 8 μm or less, or a silver resin-based conductive film having a thickness of 10 μm or less, and the overcoat film is a resin-based or glass-based film. The chip-type resistor according to claim 1, wherein 3. A back electrode straddling the primary and secondary divisional slits on the back surface of an insulating substrate in which primary and secondary divisional slits are engraved on the front and back sides so as to be divided into a rectangular shape. A back electrode film forming step of forming a film, and a front electrode film that forms a lower layer of the front electrode film on the surface of the insulating substrate so as to straddle the primary sliding slit and to be separated from the secondary sliding slit. A lower layer forming step, a resistor film forming step of connecting the lower layers of the front electrode film and forming a resistor film covering a part thereof, and an undercoat forming an undercoat film so as to cover the resistor film A film forming step, a trimming groove engraving step of engraving a trimming groove for adjusting the resistance value of the resistor film from above the undercoat film, and the insulating step so as to cover the undercoat film and the trimming groove. An overcoat film forming step of forming a overcoat film so as to avoid a part of the secondary substrate in the secondary substrate and cover a part of the secondary substrate in the insulating substrate; and A surface electrode film upper layer forming step of forming a surface electrode film upper layer so as to straddle a secondary slit of the insulating substrate on the film lower layer, and the insulating substrate along the primary direction split slit,
An insulating substrate dividing step of dividing into strips by using mechanical enemy stress, and covering the left and right end surfaces of the insulating substrate, or covering the left and right end surfaces and superimposing on the back electrode film and each part of the upper layer of the front electrode film. As described above, an end face electrode film forming step of forming an end face electrode film by a sputtering method, and a chip-shaped dividing step of dividing the insulating substrate into chips using mechanical stress along a secondary sliding slit, Forming an electrode plating film so as to cover the back electrode film, the upper electrode film, and the end surface electrode film. 4. The back electrode film forming step is a step of forming an Ag resin-based back electrode film subsequent to the overcoat film forming step of forming a resin-type overcoat film. Item 4. A method for manufacturing a chip-type resistor according to Item 3.