JPS62229992A - Multilayer printed interconnection board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a multilayer printed wiring board used in electronic equipment, and in particular to a multilayer printed wiring board with an improved insulating material between elements. Regarding.

(Prior Art) In recent years, electronic circuit boards have been multilayered in various ways due to the demand for higher density. Among these, in printing multilayers on ceramic substrates, for example, glass dielectrics are used as insulating layers. This configuration is shown in FIG. Here, 51
is a ceramic substrate, 52, 53, 54 is a conductor, 55 is R
uO2-based printed resistor, 56 is glass Xjffi body, 57
58 is a part, and 58 is an overcoat.

In the case of this configuration, since a high temperature treatment of 600 to 1000['C3] is required in the firing process of the glass dielectric 56, the 1 temperature resistance value of the RLJO2 printed resistor 55 changes. As a result, trimming of the RuO2-based printed resistor 55 becomes a process after the overcoat 58 is formed, so multilayering on the printed resistor is impossible.
The packaging density was low. There was also a problem with migration between the Aa/Pd conductors 52 and 54.

In order to solve the above drawbacks, a proposal was made to form the first conductor and the resistance layer using a thick film paste fired at high temperature, and construct the circuit using the same resin-based paste via a resin insulating layer (Japanese Patent Application Laid-Open No. 1986-1999).
No. 160687), but the resin used here is mainly an epoxy resin, which has problems with migration and deterioration of the moisture resistance of the insulation. On the other hand, thermosetting 1-2 polybutadiene resin, which has excellent insulation performance, is a suitable material as an interlayer insulator, but has the drawback of poor adhesion to ceramic substrates.

(Problems to be Solved by the Invention) As described above, in the past, when a single glass lff was used as the material for the insulating layer, there was a problem that the resistance value of the RLI02 series printed resistor changed during firing. Ta. Furthermore, when an epoxy resin or the like is used as the material for the insulating layer, problems such as migration and deterioration of the moisture resistance of the insulating layer and poor adhesion to the ceramic base material are caused.

The present invention was made in consideration of the above circumstances, and its purpose is to prevent changes in resistance value and migration of RuO2-based printed resistors, and to improve the adhesion between the insulating layer and the ceramic base material. It is an object of the present invention to provide a multilayer printed wiring board that can be made in good condition and has excellent practicality.

[Structure of the Invention] (Means for Solving the Problems) The gist of the present invention is that by selecting the material n of the insulating layer between the wiring layers,
The aim is to achieve the above objectives.

That is, in the present invention, after forming a first wiring layer using a thick film conductive paste and a resistor paste on a ceramic base material,
forming an insulating layer having a contact hole, then forming a second interconnection layer on the insulating layer;
In a multilayer printed wiring board that electrically connects the wiring layers of
Epoxy-modified polybutadiene resin is used as the material for the insulating layer.

(Function) With the above configuration, by using a resin material whose firing temperature is lower than that of a glass dielectric material etc. as an insulating layer, the resistance layer of the RuO2-based printed resistor changes when the resin material is fired. There will be no inconvenience caused. Furthermore, since the epoxy-modified polybutadiene resin has good adhesion to ceramics, it is possible to achieve good adhesion between the insulating layer and the ceramic base material.

(Example) First, before describing an example, the basic principle of the present invention will be explained.

The present inventors focused on a resin-based paste with relatively low firing humidity in order to prevent changes in the resistance value of RLIQ2-based printed resistors during repeated firing steps, which was a drawback of conventional multilayer printed wiring boards, and conducted various evaluations. The test was conducted. As a result, by using an epoxy-modified polybutadiene resin as the resin material, a multilayer structure with excellent adhesion to the ceramic base material and good electrical performance including migration was found.

The present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows a configuration diagram of a multilayer printed wiring board according to the present invention. In the figure, 11 is an alumina substrate, 12° 16.17 is a conductor layer, 13 is a RuO2 printed resistor, 14.15 is an insulating layer,
18 is a part.

The is body J112 has an Aa/PdJ9[111 pattern, and the first conductors Ji12 and R forming the first wiring layer
All of the uO2-based printed resistors 13 are 800 to 900
It was fired at a high temperature of ['C].

The resin assembly nw114 having the contact hole is mainly composed of epoxy-modified polybutadiene resin.

Here, the epoxy modified polybutadiene resin is superior to other insulating resin materials for the purpose of the present invention.
This was demonstrated through the following experiment.

First, as shown in FIG. 2, organic polymer layers 22 and 23 were formed as insulating layers on an alumina substrate 21, and a Cu1f electrode 24 was further formed thereon.

The compositions of the organic polymers 12 and 13 used are shown in Table 1 below.

Table 1 PCT of such samples (121°C, 2ati)
The insulation resistance was measured after 20H and 140H. The results are shown in FIG. As can be seen from this figure, although a decrease in insulation resistance of about 103[Ωα] can be seen in the structure A, the specific resistance is still more than 10!3 [Ωax], which is a sufficiently practical value. In addition, by adopting the configuration B, the insulation resistance decreases by 102 [Ωcrtt
] or less. On the other hand, a decrease in IR1 of 10 days [Ωca] was observed in the case of the configuration D, and a decrease in IR1 of 10 days [Ωca] was observed in the case of the configuration E, which was a problem in practical use. Also,
Although the configuration C had the same level as the configuration B, it had poor adhesion to the alumina substrate 21 and was not desirable as an insulating layer.

In addition, configurations A and B performed significantly better in migration tests as well. Using the structure shown in Figure 1 as a sample, the pattern spacing of the second layer conductor 16 is 0.5.
Two Cu conductors of [am] are formed, and 1
Apply a voltage of 0 [V], PCT (121℃, 2#lm
) Medium 1'408 current conduction test was conducted. As a result, when using epoxy-modified polybutadiene resin as the organic polymer layer (insulating layer), migration occurred at 215%.
It was 0. Also, for thermosetting 1-2 polybutadiene resin, it is 0150, and for epoxy, it is 4515.
For polyimide, occurrence of migration of 50,150 was observed.

What can be considered from this experiment is that epoxy and polyimide resins have many hydrophilic groups in their molecules, so they easily absorb water, which causes a decrease in insulation resistance and the occurrence of migration. There is. In contrast, epoxy-modified polybutadiene resin has considerably fewer hydrophilic groups. Furthermore, it is thought that this difference was noticeable because the thermosetting 1-2 polybutadiene resin does not have parent wood groups. However, although thermosetting 1-2 polybutadiene resin has excellent water resistance, it has poor adhesion to ceramics, and when used alone, it causes cracks and peeling, making it impractical. Therefore, epoxy-modified polybutadiene resin was used in the present invention because it has superior water resistance compared to conventional epoxy, polyimide, etc., and also has good MIW strength with ceramics. Here, epoxy modified polybutadiene resin and thermosetting 1-
It is clear that water resistance is further improved by using it in combination or in combination with 2-polybutadiene resin.

Next, the second conductor layer is formed by printing or plating using a paste mainly composed of an organic metal and a metal filler such as Qu powder or He〇 powder, etc., or by electroless plating of CU, etc. The pattern may be formed by forming the pattern on the body layer and then etching it, or by vapor deposition, transfer method, or the like. Among these, the printing method is preferable because it has good workability and can be manufactured in a dry manner.

Next, when increasing the number of layers, the conditions for forming the organic polymer layer and the second conductor layer may be repeated. Here, a low-temperature curing resistor such as a carbon resistor may be added to the top layer as necessary without departing from the spirit of the present invention.

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

<Example 1> In the configuration shown in FIG. 1, alumina 9 is used as the substrate 11.
6% substrate (50.8MX 50.8#l X O,83
The surface was subjected to trichlene cleaning using 5try).

After that, Ac+/Pd paste (D manufactured by Shoei Kagaku Co., Ltd.)
-4344) and then 12
After drying at 0 [°C] for 5 minutes, baking was performed at 850 [°C] in the atmosphere to form the first conductor layer 12.

Next, screen printing was performed using RLJQz-based resistance paste (R-5000 series manufactured by Shoei Kagaku Co., Ltd.), and after drying at 120 [°C] for 15 minutes, it was dried at 850 ['C] in the air.
The Ru Q 2-based printed resistor 13 was formed by firing.

Next, epoxy-modified polybutadiene resin (Nippon Soda)
Co., Ltd. (EP-1054) having the composition shown in Table 2 below was blended and kneaded with three rolls until it became a paste.

Table 2 Next, 5% of an imidazole curing agent was added to this paste immediately before printing, and screen printing was performed.
After drying at [°C] for 15 minutes, dry at 350 ['C] in a nitrogen atmosphere.
Insulation that is fired and has contact holes! ! 1
4 was formed.

After that, CU paste (CT-2 manufactured by Toshiba Chemical Corporation)
21), and after drying at 120 [°C] for 10 minutes, baking was performed in a nitrogen atmosphere of 350 ["C] to form the second conductor layer 16. Then, in the same manner as above, the second conductor layer 16 was formed. forming an insulating layer 15 and a third conductor layer 17;
A multilayer printed wiring board was created.

Here, FIGS. 4(a) to (C) show the resistance value of the produced multilayer printed wiring board when RuOz-based printing was performed with low printing resistance, and the change in resistance value during the firing process of 350["C]. As you can see from this figure, the change in resistance value is 0.6%
It was below. Further, the decrease in insulation resistance after 40 hours in PCT (121° C., 2 atm) was only three digits compared to the initial value, and there was no practical problem. Regarding migration occurrence, PCT (121℃, 2atta)
When conducting a medium 10 [V] current test for 40 hours, the number of samples was 5.
2151 out of 0! However, compared to conventional resins such as epoxy or polyimide, the incidence was significantly lower.

Example 1 Example 2> Using the same epoxy-modified polybutadiene resin as in Example 1, cover the first conductor 12 of the insulating layer in FIG.
The bottom part of 6 was mixed with a composition mainly composed of thermosetting 1-2 polybutadiene resin (B-3000 manufactured by Nippon A-Datsu Co., Ltd.) and kneaded until it became a three-roll paste. Insulating layers 14 and 15 were formed to produce a multilayer printed wiring board similar to that of Example 1.

The change in resistance value of the RLJ Qz unprinted resistor 13 here was 0.6%. In addition, PCT (121℃,
The decrease in the absolute resistance after 40 hours in 2 atm) remained at two digits compared to the initial value, and there was no practical problem. In addition, regarding the occurrence of migration, PCT (121℃
, 2atm) 10 [408 V current conduction tests were performed, and 0.150 migrations occurred out of 50 samples, which was good.

Comparative Example 1 A multilayer printed wiring board similar to Example 1 was prepared using glass dielectric paste (G-5232 manufactured by Shoei Kagaku Co., Ltd.) for the insulation 11114.15 in FIG. 1. Here, The glass dielectric was dried at 150 ['C] for 15 minutes, and then fired at 8
It was carried out in the atmosphere at 50['C].

After this, the resistance value when forming the RuO2-based printed resistor and 850
The change in resistance value during the firing process of ['C] is ±50
[%], which was a practical problem.

Comparative Example 2> Epoxy resin-based insulating resin (Asahi Chemical !IIccR-5064) was used for the insulating layers 14 and 15 in Figure 1.
A multilayer printed wiring board similar to that of Example 1 was prepared.

Here, the epoxy was cured at 150['C] for 20 minutes.

After this, the resistance value during formation of the RL+-02 series printed resistor and the change after the 350['C] process were good, being less than 0.6U%;
The reduction in insulation resistance after 0H was more than 8 orders of magnitude lower than the initial value. In addition, regarding the occurrence of migration,
T (121℃, 2atm) 10[1 energization test was performed 408 times, and the number of samples was 45150vI for 50111 samples.
Migration occurred in A, which caused a practical problem.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to extremely reduce the change in resistance value due to the RuQz-based printed low printed resistor process, and also to improve moisture resistance and prevent the occurrence of migration. obtain. Moreover, the adhesion between the insulating layer and the ceramic base material can be improved. For this reason, a reliable thick-film multilayer printing arrangement that allows high-density mounting! A substrate can be provided.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the schematic structure of a multilayer printed wiring board according to the present invention, FIG. 2 is a sectional view showing the structure of a sample for moisture resistance testing of an insulating layer, and FIG. 3 is an IP! A characteristic diagram showing the change in edge resistance resistance over time. Figure 4 is a characteristic diagram showing the resistance change rate of RuO2-based printed low antibody due to temperature process. Figure 5 is a multilayer printed wiring board using a conventional high temperature fired glass dielectric. FIG. 11...Alumina substrate (ceramic base material), 12゜1
6.17...Conductor, 13...RLJO2-based printed resistor, 14.15...Insulating layer, 18...Component. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 In 208 40H (hours) -. Figure 3

Claims (3)

[Claims] (1) After forming a first wiring layer using thick film paste and resistance paste on a ceramic base material, forming an insulating layer having contact holes, and then forming a second wiring layer on the insulating layer, A multilayer printed wiring board electrically connecting first and second wiring layers, characterized in that the insulating layer is made of epoxy-modified polybutadiene resin. (2) The multilayer printed wiring board according to claim 1, wherein a composite or combination of an epoxy-modified polybutadiene resin and a thermosetting 1-2 polybutadiene resin is used as the insulating layer. (3) The multilayer printed wiring board according to claim 1, characterized in that a paste containing an organic polymer and a metal filler as main components is used as the conductor layer other than the first wiring layer. .