JPH01184904A - Ceramic substrate for electronic component - Google Patents

Abstract

PURPOSE:To reduce the irregularity in thickness of printed films as well as to contrive improvement in dividability by a method wherein the shape of warpage of the substrate in transverse and longitudinal directions is formed into a projecting shape. CONSTITUTION:Grooves 2 and 3, to be used for dividing a substrate, are provided on the surface of a ceramic substrate 1, and the shape of the warpage of the ceramic substrate 1 is formed into a conical shape against its surface. It is desirable that the measurement of the A shown in the diagram is 30mum, the B and C is 15mum, the D is 40mum, and the E and F is 20mum, for example. When the title substrate is constituted as above-mentioned, the warpage of the substrate is turned flat when working and sintering processes are conducted, and also when a glass paste printing process and the lateral direction dividing groove forming process are conducted. Also, as the irregularity in the thickness of the printed film can be reduced, the yield of resistance value can be improved, and the irregularity in total thickness of finished articles can also be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a ceramic substrate for electronic components used in chip components and the like used in electronic equipment.

BACKGROUND OF THE INVENTION Generally, as shown in FIG. 5, a chip resistor is manufactured by coating a resistor paste on a ceramic substrate 11 by screen printing or the like and baking it to provide a resistor 12, and then connecting the resistor 12. In addition, an electrode 13 is provided to extend from the end surface to the bottom surface of the ceramic substrate 11, and a glass film 14 is further provided to protect the resistor 12.

Conventionally, ceramic substrates for electronic components used in this type of chip resistor and the like have had shapes as shown in FIGS. 6 to 8. Figures 6 to 8 show schematic diagrams of ceramic substrates for making chip parts, where 16 is the ceramic substrate before division, 16 is a vertical division groove, and 17 is a horizontal division groove. If the surface with the dividing grooves 16 and 1 is the front surface, the horizontal warpage of the board is as follows when viewed from the side.
It has a valley shape with respect to the surface, and the warpage of the substrate in the vertical direction also has a valley shape with respect to the surface when viewed from the side.

Such conventional ceramic substrates have the following drawbacks because the warpage of the substrate is in the shape of a valley, and the valley shape of the ceramic substrate progresses as shown in Fig. 13 with each step of processing and firing. there were.

FIG. 9 shows the paste state when screen printing is performed in a typical chip resistor manufacturing process. 1st
As shown in FIG. 3, after the first firing, the valley shape of the ceramic substrate 15 is extremely advanced, so when the resistor and the glass portion are formed by screen printing as shown in FIG.
The film thickness of No. 8 varied from place to place, resulting in deterioration of resistance value yield and variation in total product thickness.

Further, FIG. 10 is a front view of the step of dividing the ceramic substrate after the third firing along the horizontal dividing grooves 17, and 19 is the dividing point of the ceramic substrate 15) 20
．． 21 is a dividing jig.

In such a dividing point 19, the transverse rupture force for dividing is concentrated at the dividing point 19, and after dividing, the 11th
This method has disadvantages in that irregularly shaped portions 22 as shown in the figure are likely to occur, variations in the division dimensions become large, and troubles are likely to occur when mounting chip components. In addition, the ceramic substrate 15 is slightly bent at the moment of dividing, and stress is applied to the vertical dividing grooves 16, so that the horizontal dividing grooves 17
12, the vertical dividing groove 16 is also divided, resulting in defective division as shown in FIG. 12.

Problems to be Solved by the Invention In order to reduce the variation in printed film thickness on such conventional ceramic substrates, it is necessary to reduce the depth of the dividing grooves and reduce the warpage of the ceramic substrate. On the other hand, in order to improve the dividing property, the depth of the dividing groove must be increased, but this increases the warpage of the ceramic substrate and causes unevenness in printed film thickness. It has problems that have a negative impact on

An object of the present invention is to stabilize the variation in printed film thickness of a ceramic substrate and to solve the problem of divisibility as described above.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention is such that the surface of the ceramic substrate on which the dividing grooves are provided is warped into a chevron shape.

Effect: According to this configuration, by performing process processing and baking, the warpage of the substrate is reduced to 7 rasot during printing of the resistor, Galanu paste, and the process of dividing the horizontal dividing grooves, reducing the variation in printed film thickness. In addition, in the process of dividing the horizontal dividing groove, the dividing point becomes a line, the transverse rupture force for dividing is distributed, and irregular shapes do not occur. , there is no bending of the substrate during division, the stress applied to the vertical division grooves is reduced, and division defects can be reduced.

EXAMPLE Hereinafter, the present invention will be explained using an example of a ceramic substrate for a chip resistor with reference to the drawings.

Fig. 1 shows a ceramic substrate according to an embodiment of the present invention, Fig. 2 shows a warped shape of the ceramic substrate viewed from the horizontal direction, and Fig. 3 shows a warped shape of the ceramic substrate seen from the vertical direction. There is. That is, the present invention provides dividing grooves 2.3 on the surface of the ceramic substrate 1 as shown in FIGS. 2 and 3.
The ceramic substrate 1 is curved in a chevron shape with respect to its surface. For example, the dimensions of the person in FIG. 2 are 30 μm, B and C are 15/jm, D in FIG. 3 is 40 μm, and E and F are 20 μm.

The warped shape of the ceramic substrate in the horizontal direction corresponds to FIG. 7, and the warped shape of the ceramic substrate in the vertical direction corresponds to FIG. 8.

Hereinafter, specific effects when using the ceramic substrate of the present invention will be described.

1,000 ceramic substrates of the present invention were made and put into a chip resistor production line to check the warped shape of the substrate, check the resistance value variation, check the glass film thickness variation, and check the splitting irregularity occurrence rate. We checked the split defect rate.

As shown in Figure 4, the warped shape of the substrate due to process processing and firing has become almost flat, so the resistance value variation can be reduced from the conventional σ angle of 4% to σ angle of 1.6%. Also, the glass film thickness variation is conventionally σ = 6.8 μm.
This can be reduced to σ=3.6 μm. In addition, the incidence of splitting dysmorphia was previously 3.2%, but
The split defect rate was reduced by more than half to 1.3%, and the split defect rate was also 0.
What used to be 8% can be halved to 0.3%.

Effects of the Invention As described above, in the ceramic substrate of the present invention, by making the curved shape of the substrate in the horizontal and vertical directions into a chevron shape, it is possible to reduce variations in printed film thickness and improve divisibility.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a ceramic substrate for electronic components according to an embodiment of the present invention, FIG. 2 is an explanatory diagram seen from the horizontal direction of FIG. 1, and FIG. 3 is an explanatory diagram seen from the vertical direction of FIG. 1. An explanatory diagram, Fig. 4 is an explanatory diagram showing the state of warping of the same board due to process processing and firing, Fig. 5 is a cross-sectional view showing a general chip resistor, and Fig. 6
The figure is a perspective view showing a conventional ceramic substrate, and FIG.
8 is a sectional view seen from the horizontal direction of the figure, FIG. 8 is a sectional view seen from the vertical direction of FIG. 6, FIG. 9 is an explanatory diagram showing the printed film thickness state when using a conventional ceramic substrate, The figures are a front view showing the process of dividing the horizontal dividing groove, Figures 11 and 12.
10 is a perspective view showing the problem that occurs when the substrate is divided according to FIG. 10, and FIG. 13 is an explanatory view showing the state of warpage caused by process processing and firing of a conventional ceramic substrate. 1...Ceramic substrate, 2.3...Dividing groove. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
--Ceramic base plate 2, 3-11 minute 91 appetizer figure 1! Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Lateral opening〉 Fig. 7/g Fig. 8 Fig. 9 January Fig. 10 Fig. π Fig. 13

Claims (1)

[Claims] 1. A ceramic substrate for electronic components, characterized in that it has dividing grooves on its surface for dividing into a large number of parts, and has a curved surface so as to have a chevron shape.