JPH0367324B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method of manufacturing a small resistor.

(Prior Art) For example, a small resistor with vertical and horizontal dimensions of several millimeters is manufactured approximately as follows. In other words, a large substrate such as ceramic is prepared with a large number of vertical and horizontal scribe lines (grooves with a triangular cross section, for example), and a unit area divided by the scribe lines (this is the size of one small resistor) is prepared on the surface of the substrate. A pair of electrodes facing each other are sequentially formed on each surface of the electrode, and a resistor is sequentially formed as a thick film so as to span between the two electrodes. Thereafter, an insulating protective layer, such as a glass layer, is provided on the surface of the resistor. Then scribe vertically and horizontally along the scribe line. Next, a metal film such as tin is formed on the surface of the electrode by plating to make it easier to solder the electrode.

By the way, in such a manufacturing process, when forming the glass layer, the glass paste is printed and fired across each unit area.
The glass layer is naturally formed across the boundaries of the unit area. Therefore, when scribing along the scribe line, the glass layer simultaneously breaks. At this time, burrs often appear on the glass layer.
If you leave the burrs like this,
For example, when this is grasped with a chuck or the like in order to automatically load it onto a circuit board or the like, the burr may be damaged. It is fine if only the burr is damaged, but the glass portion covering the resistor surface may also be chipped. Such a shape impairs its value as a product, and it has also been reported that the resistor is exposed, deteriorating its characteristics.

In order to prevent this, it has been considered to form the glass layer so that it does not extend over each unit area, that is, to form it independently for each unit area (see Japanese Utility Model Publication No. 79501/1983). Figure 3 is a plan view of the conventional example, in which a small resistor D is provided with a pair of electrodes B on the surface of a substrate A and a resistor C spanning between the two electrodes, with a glass layer covering the surface of the resistor C. It is configured by providing E. The glass layer E is formed independently in each unit area so as not to be continuous with the surface of the adjacent unit area before scribing at the time of formation.

When forming the glass layer E in this way,
The glass layer E is not scribed even during scribing. Therefore, it is convenient that burrs do not appear during scribing. However, such a configuration causes the following problems.

That is, as mentioned above, it is necessary to form a plating layer on the surface of the electrode, but since the glass layer E is located away from the scribe line, a part of the opposing edge b of the electrode is covered by the glass layer E. become uncovered. If plating is applied with the edge b of electrode B exposed in this way, even if a plating layer is formed on the surface of electrode B, this
The edge b of the other electrode B grows further and faces
It begins to move towards. Therefore, both electrodes B may be connected to each other due to the grown plating. Furthermore, even if they are not connected, the plating grows along the side edge e of the glass layer E and becomes exposed on the surface, which may spoil the appearance.

(Problems to be Solved by the Invention) The purpose of the present invention is to manufacture small resistors by easily avoiding the occurrence of burrs when scribing large substrates and the poor connection between electrodes or poor appearance due to the growth of plating. shall be.

(Means for Solving the Problems) When applying paste for a glass layer across the boundaries of each unit area on the surface of a large substrate, the present invention forms a plurality of windows by patterning across the boundaries. It is characterized in that it is baked after it has been heated.

(Function) If a window is patterned, the paste around the window will soften and flow during firing, filling the window. Therefore, even if the glass layer near the boundary of the unit area is initially printed with the same thickness as other parts, only this part becomes thinner than the other parts. Therefore, even if you scribe after firing,
Since the glass layer near the scribing area is thin, there are almost no burrs. Since the edges of adjacent windows are continuous with the glass paste from the beginning of printing, a glass layer is formed along the direction across the scribe line even after firing. Therefore, in the subsequent plating process, the electrodes are reliably prevented from being connected to each other due to the growing plating.
And as Metsuki grows up, there will be no more disgrace.

(Example) An example of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 shows a part of a large substrate. Reference numeral 1 is an insulating substrate such as ceramic, on which scribe lines 2 are formed vertically and horizontally. The area defined by adjacent vertical and horizontal scribe lines is defined as a unit area 3. Electrodes 4 paired with each unit area 3
A resistor 5 is formed of a thick film so as to span both electrodes 4. 6 is a glass layer for insulation and protection. These configurations are not particularly different from the previous ones.

According to this invention, the glass layer 6 is formed across the unit area 3. Then, a plurality of windows 8 are formed along the boundary line 7 in a portion of the glass layer 6 that straddles the boundary line 7 of the unit area 3 . To explain this more specifically, the glass layer 6
is formed by printing and baking glass paste, and during printing, a plurality of windows 8 are formed across the boundary line 7.
pattern so that it is formed. In this case, the printing thickness of the glass paste is uniform (see Figure 2).

After printing the glass paste, it is fired. At this time, the paste softens and becomes fluid due to the heating, and flows into the window 8 to which no paste has been applied. Therefore, even if the printing thickness near the area where the window 8 is formed is initially the same as that of other parts, the paste thickness gradually becomes thinner than the other parts. After reaching the softened state in this way, the state shifts to the fired state. In this case, the window 8 does not need to be completely filled with the paste, and traces of the window formation may remain after firing. FIG. 3 shows a cross section of one unit area after firing.

After baking as described above, the substrate 1 is scribed along the scribe line 2. After that, the surface of the electrode 4 is plated with tin or the like. Even though the window 8 exists between the electrodes 4, the glass layer is interposed so that the plating will not grow from one electrode to the other. Therefore, the electrodes 4 will not be connected to each other due to the growing plating, and the growing plating will not cause an unsightly appearance.

(Effects of the Invention) As detailed above, according to the present invention, the thickness of the glass layer on the scribe line is reduced, so that
Scribing also makes it difficult for burrs to occur, and even if they do occur, they are small depending on the thickness, so there is no particular problem, and the growth of plating is inhibited, so the growth of plating prevents the electrodes from collapsing. The effect is that there is no unsightly appearance due to connection or growth plating.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the manufacturing process according to the present invention, FIG. 2 is a sectional view during glass paste printing, FIG. 3 is a sectional view after firing, and FIG. 4 is a plan view of a conventional example. 1...Large board, 2...Scribe line, 3
... Unit area, 4 ... Electrode, 5 ... Resistor, 6
...Glass layer, 8...window.

Claims (1)

[Claims] 1. The surface of a large substrate is divided into a plurality of unit areas by vertical and horizontal scribe lines, and in each unit area, electrodes that form a pair with each other and a resistor that spans between the electrodes are formed, and further, a resistor that spans the unit area is formed. A protective insulating paste is patterned and printed on the surface of the resistor so that a window is formed across the boundary of the unit area, and then heated so that it flows into the window. A method of manufacturing a small resistor comprising firing, then scribing along the scribe line, and plating the surface of the electrode.