JPS6011479B2 - Manufacturing method of ceramic multilayer circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low electrical resistance metal conductor material obtained by sintering at a normal ceramic firing temperature, and a method for manufacturing a ceramic multilayer circuit board using the conductor material.

Conventionally, the method for making ceramic multilayer circuit boards used in electronic circuits is the thick film method, in which conductor paste and insulator paste are alternately printed and fired on a fired ceramic substrate, and this process is repeated to create multiple layers. There is a printing method and a lamination method in which a green body of a multilayer circuit board is formed by printing or lamination on a raw ceramic sheet, and the conductor and ceramic of the green body of the multilayer circuit board are simultaneously fired.

Since the printing method and the lamination method obtain a ceramic multilayer circuit board by simultaneously firing the conductor and the ceramic, firing is performed only once, and the number of work steps is reduced compared to the thick film method. Furthermore, since the ceramic multilayer circuit boards obtained by these methods have a monolithic structure, they have high mechanical and thermal strength and are highly reliable. However, in these methods, the ceramic and conductor are usually fired at a high temperature of 1,400 to 1,600 oo, so the conductor materials used in these methods have a melting point at least higher than this firing temperature and are susceptible to evaporation, scattering, etc. during firing. The material must not cause For this reason, high melting point metals such as W and Mo are generally used. However, the melting point of these high-melting point metals is 2,500 oo or higher, and sufficient burning stripes cannot be formed at the above-mentioned firing temperature, so that the conductor tends to become a sintered body with many voids and high electrical resistance. The present invention has been devised to improve this drawback. Therefore, the present invention is characterized in that Ti and Zr powders of 1% by weight or less are added to a high-melting point metal powder such as Mo or W as a metal conductor material and then heated and fired. In the process of manufacturing a ceramic multilayer circuit board by simultaneous firing, Ti and Zr powders of 10 weight percent or less are added to the high melting point metal powder such as Mo or W forming the conductor. Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows the first step of the manufacturing process for obtaining a multilayer circuit board. In this process, a conductor circuit 2 is printed on a green ceramic sheet using a conductor paste. The composition of this conductive paste is shown in Table 1. This is a paste containing Mo or W to which Ti and Zr, which are the main points of the present invention, are added as sintering aids. Table 1 Mo and W Paste Z Exfusion Next, as shown in FIG. 2, a ceramic paste is printed to form an insulating layer 3.

On top of this, conductive paste and ceramic paste are alternately printed and the layers are stacked as shown in FIG. This is the necessary layer. The unfired body of the ceramic multilayer circuit board formed by stacking several layers is placed in a heating furnace and fired at about 1600 o'clock in a humid hydrogen atmosphere to obtain a multilayer circuit board. The electrical resistance of the conductor circuit in the multilayer circuit board thus obtained was measured using the four-probe method, and the results are shown in Table 2.

Table 2: Addition amount of Ti and Zr and electrical resistance.
This figure shows the relationship between the amount of added sintering aids such as Zr and electrical resistance.If the amount of Ti and Zr added is small, the effect is not noticeable, and if the amount added is too large, Mo, W
It can be seen that the electrical resistance increases because it is alloyed with high melting point metals such as.

For this reason, it is necessary to add an appropriate amount of a sintering agent. The amount of this sintering aid added varies depending on the type of high melting point metal used, the type of sintering aid, the shape of the powder particles, etc., but it is suitably 1 weight percent or less based on the high melting point metal. As explained above, Ti is added to high melting point metal powder such as Mo and W as a sintering aid.
By adding powders such as , Zr, etc., the sintering of high melting point metals such as Mo'W is activated at normal ceramic sintering temperatures, and a dense compact with few voids can be obtained.

Therefore, the electrical resistance of this sintered body can be made 2/3 to 1/2 lower than that of ordinary Mo, W, etc. Furthermore, by applying these conductors with low electrical resistance to ceramic multilayer circuit boards, it becomes possible to narrow the line width of the conductor circuit, thereby making it possible to improve the wiring density.

[Brief explanation of drawings]

1 to 3 are cross-sectional views of a multilayer circuit board in each manufacturing process according to the method for manufacturing a ceramic multilayer circuit board according to the present invention. 1...Ceramic raw sheet, 2...Conductor circuit, 3.
...Insulating layer. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. In the process of manufacturing a ceramic multilayer circuit board by simultaneously firing a conductor and ceramic, the conductor is formed by adding 10% by weight or less of Ti to a high melting point metal powder such as Mo or W.
and a method for manufacturing a multilayer circuit board, characterized in that Zr powder is added thereto.