JPH0969406A - Manufacture of square-shaped thin film chip resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the insulating property and the split form of a board, and to simplify a manufacturing process by a method wherein a thin film resistor layer is formed on the surface having no split groove and it is diced using an insulating board having split groove in longitudinal and lateral directions only on the surface of one side. SOLUTION: A metallic component is baked on the surface (surface having no split groove) and the back side of an insulated board 1 having a plurality of split grooves 2 on the back side in longitudinal and lateral direction, and a thin film upper surface electrode layer 3 and a thin film backside electrode layer are formed. A thin film resistor 5 is formed on the thin film surface electrode layer 3, and it is shaped up to a resistance pattern 6 by etching. The resistance pattern 6 is formed into a stable film by heat treatment, and after its resistance value has been corrected by laser trimming, a protective coat 7 is formed by resin paste. The board 1 is divided into rectangular boards 1a, and after a thin film edge face electrode layer 8 has been formed on the edge face, the boards 1a are formed into a diced board 1b, and each electrode layer is protected by a plated layer 9. As a result, the insulating property of the board is improved, and the manufacturing process can be simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a rectangular thin film chip resistor used in various electronic circuits.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of electronic devices, there is an increasing demand for high-precision products in order to increase the mounting density of electronic components used in circuit boards. Even for rectangular chip resistors, demand for high-precision thin film chip resistors with a high resistance tolerance is increasing due to no adjustment of electronic circuits. With the increasing demand, low cost demands are placed on electronic device manufacturers. It is coming out from the side.

A conventional method for manufacturing a rectangular thin film chip resistor will be described below with reference to the drawings.

FIG. 3 is a diagram showing a manufacturing process of a conventional rectangular thin film chip resistor. First, as shown in step A, a heat-resistant insulating groove-less insulating substrate 21 made of high-purity alumina or the like is received.

Next, as shown in step B, the insulating substrate 21
Form a thin film resistor such as Ni-Cr on the top by sputtering,
As shown in step C, the thin film resistor is etched to form the resistance pattern 22.

Next, as shown in step D, a thin film electrode of Cu or the like is formed on the resistance pattern 22 by sputtering, and as shown in step E, a thin film electrode is formed on the electrode pattern 23 by etching.

Next, as shown in step F, in order to make the resistance pattern 22 and the electrode pattern 23 stable films,
Heat treatment is performed at a temperature of 350 to 400 ° C. in nitrogen or the like.

Next, as shown in step G, the resistance pattern 2
In order to correct the resistance value of No. 2 to a predetermined value, the resistance value is corrected by laser trimming or the like.

Next, as shown in step H, in order to protect the resistance pattern 24 whose resistance value has been corrected, a protective coat 25 made of a thermosetting resin is applied so as to cover at least the resistance pattern 22.

Next, as shown in step I, the insulating substrate 21
As a preparatory step for dividing and dividing the end face electrode layer 27, the groove 26 for division is formed in the insulating substrate 21.

Next, as shown in step J, the insulating substrate 21
Is divided into strip-shaped substrates 21a, and as shown in step K, end-face electrodes for forming the end-face electrode layers 27 are formed on the end faces of the strip-shaped substrates 21a by using sputtering or the like.

Next, as shown in step L, as a preparatory step for plating the exposed electrode surface, the strip-shaped substrate 21a is divided into individual substrates 21b.

Finally, as shown in the step M, the electrode thin film chip resistor 28 is manufactured by forming the electrode plating 28 in order to ensure reliability during soldering.

As another method, there is also a method in which an insulating substrate having vertical and horizontal dividing grooves on both sides is used as the insulating substrate and a thin film resistor such as Ni-Cr is sputtered thereon. However, with this method, the thin film resistor material penetrates into the dividing grooves, and it is difficult to completely remove it, so that the number of steps must be increased for this removal.

[0015]

However, the conventional method of manufacturing a thin film chip resistor has the following problems.

(1) Since a groove for dividing is formed by laser scribing after forming a pattern on the insulating substrate 21 having no dividing groove, not only the appearance is impaired, but microcracks of the substrate due to the thermal shock of the laser are generated. Easily occurs, which may cause deterioration of insulation. In addition, the process tends to be complicated.

(2) When a thin film resistor is formed on a substrate having a dividing groove, the thin film resistor material enters the dividing groove and is difficult to remove. When the thin film resistor material remains in the dividing groove, the resistors adjacent to each other are connected to each other, and the resistance value cannot be corrected accurately. Further, the electrode plating 28 is formed on the remaining portion in the subsequent plating process. It was formed, and the characteristics and appearance were deteriorated.

In order to solve the above-mentioned conventional problems, it is an object of the present invention to provide a method for manufacturing a rectangular thin film chip resistor which is inexpensive and has an excellent substrate insulating property by a simple process. Had.

[0019]

In order to achieve the above object, a method for manufacturing a rectangular thin film chip resistor according to the present invention uses an insulating substrate having vertical and horizontal dividing grooves only on one surface, It is characterized in that a thin film resistor layer is formed on a surface of the insulating substrate having no dividing groove and divided into individual pieces.

[0020]

According to the present invention, since an insulating substrate having a dividing groove on only one surface is used in advance, it is not necessary to form a dividing groove by laser scribing as in the conventional case, so that the insulating property of the substrate is improved. Is improved, the divided shape is good, and the process can be simplified.

Further, by forming the thin film resistor layer on the surface of the insulating substrate having no dividing groove, the thin film resistor material does not remain in the dividing groove, and the resistance value due to the connection of the resistors adjacent to each other. It is possible to prevent problems caused by correction and formation of plating on the remaining portion.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a rectangular thin film chip resistor according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a process diagram showing a method of manufacturing a rectangular thin film chip resistor according to an embodiment of the present invention, and FIG. 2 is a sectional view of the same. In the present embodiment, in order to distinguish between the front and back surfaces of an insulating substrate having 96% alumina (hereinafter referred to as "96 alumina substrate"), the surface having the dividing groove will be described as the back surface and the surface having no dividing groove will be described as the front surface.

First, as shown in step A, the 96 alumina substrate 1 having excellent heat resistance and insulating properties is received. On the back surface of the 96-alumina substrate 1, a plurality of vertical and horizontal dividing grooves 2 are formed for dividing into strips and individual pieces.

Next, as shown in step B, an electrode paste made of a metal organic compound containing Au as a main component is screen-printed and dried on the surface of the 96 alumina substrate 1 (the surface having no dividing groove), and the 96 alumina substrate is further dried. In order to blow only the organic component of the metal organic electrode paste on the back surface of No. 1 and to bake only the metal component on the alumina substrate 1, a belt type continuous firing furnace was used at a temperature of 850 ° C. for a peak time of 6 minutes and IN-O.
The thin film top surface electrode layer 3 and the thin film back surface electrode layer 4 are simultaneously formed by firing according to a profile of UT time 45 minutes.

Next, as shown in step C, a Ni--Cr thin film resistor 5 is formed by sputtering on the surface of the 96 alumina substrate 1 on which the thin film upper surface electrode layer 3 is formed (the surface having no dividing groove). .

Next, as shown in step D, the thin film resistor 5
Etching to shape the resistance pattern 6 is performed.

Next, as shown in step E, heat treatment is performed in nitrogen at a temperature of 250 to 400 ° C. in order to form a stable film of the resistance pattern.

Next, as shown in step F, the resistance value is corrected by laser trimming in order to correct the resistance value of the resistance pattern 6 to a predetermined value.

Next, as shown in step G, in order to protect the resistance pattern whose resistance value has been corrected, a resin paste is screen-printed and heat-cured to form a protective coat 7.

Next, as shown in step H, as a preparatory step for dividing the 96 alumina substrate 1 and forming the thin film end face electrode layer 8, the 96 alumina substrate 1 is divided into strip substrates 1a. Then, as shown in step I, an end face electrode is formed on the end face of the strip-shaped substrate 1a by sputtering to form a thin film end face electrode layer 8 of Ni—Cr.

Next, as shown in step J, as a preparatory step for plating the exposed electrode surface, a secondary substrate division for dividing the strip substrate 1a into individual substrates 1b is performed.

Finally, as shown in step K, the exposed thin film upper surface electrode layer 3, the thin film back surface electrode layer 4, and the thin film end surface electrode layer 8 are prevented from electrode erosion during soldering and reliability at the time of soldering. Ni, S by electrolytic plating to secure the
A square thin film chip resistor is manufactured by forming an n-Pb plating layer 9.

Through the above steps, a rectangular thin film chip resistor according to an embodiment of the present invention was manufactured. As a result, the problems caused by the connection between adjacent elements at the time of resistance value correction, which was a problem in the conventional manufacturing method, and the plating formation due to the thin film resistor remaining in the vicinity of the dividing groove in the finished product does not occur. It was The divided shape of the finished product after electrode plating was also better than before.

Also, a prismatic thin film chip resistor of the present invention,
Comparison of resistance variation, resistance temperature characteristics, and current noise characteristics with the conventional rectangular thin-film chip resistors revealed that they were equivalent.

In this example, the thin film top surface electrode layer and the thin film back surface electrode layer were formed using the metal organic electrode paste, but this does not limit the manufacturing material and method, and is similar to the thin film resistor. The method (sputtering and etching) is also possible.

[0037]

As described above, according to the present invention, it is necessary to form a groove for division by laser scribing, which has been conventionally required, by using an insulating substrate in which a dividing groove is formed on only one surface in advance. (EN) A manufacturing method of a rectangular thin film chip resistor capable of reducing the manufacturing cost by simplifying the manufacturing process and improving the insulating property of the substrate.

Further, by forming the thin film resistor layer on the surface of the insulating substrate having no dividing groove, the thin film resistor material does not remain in the dividing groove, and the resistance value due to the connection of the resistors adjacent to each other is eliminated. The present invention provides a method for manufacturing a rectangular thin film chip resistor, which can prevent defects caused by correction and formation of plating on a residual portion and can improve the quality level of products.

[Brief description of drawings]

FIG. 1 is a process diagram showing a method for manufacturing a rectangular thin film chip resistor according to an embodiment of the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a process diagram showing a method of manufacturing a conventional rectangular thin film chip resistor.

[Explanation of symbols]

 1 96 Alumina substrate 2 Dividing groove 3 Thin film upper surface electrode layer 4 Thin film back surface electrode layer 5 Thin film resistor 7 Protective coat 8 Thin film end surface electrode layer 9 Plating layer

Claims (2)

[Claims] 1. A rectangular thin film chip resistor formed by forming a thin film resistor layer on a surface not having a dividing groove of an insulating substrate having dividing grooves in the vertical and horizontal directions on only one surface and dividing the thin film resistor into individual pieces. Manufacturing method. 2. A pair of thin film upper surface electrode layers are formed on a surface having no dividing grooves of an insulating substrate having dividing grooves in vertical and horizontal directions on only one surface, and the pair of thin film upper surface electrode layers are formed on this surface. To form a thin film resistor layer so that it overlaps with, modify the resistance value of this thin film resistor layer, form a protective film layer so as to completely cover this thin film resistor layer, and form a thin film end face electrode layer. As a preparatory step for electrode plating, the substrate is primary-divided, and a pair of thin-film end surface electrode layers are formed on the surfaces exposed by the primary division so as to be electrically connected to the pair of thin-film upper surface electrode layers. A method of manufacturing a rectangular thin film chip resistor, characterized in that a substrate is divided into individual pieces and electrode plating is formed on the exposed electrode portions.