JPH034593A - Thin film substrate - Google Patents

Abstract

PURPOSE:To improve the signal propanation speed of a thin film substrate of this design by a method wherein the surface of a conductive layer is made exposed to air as much as possible so as to lessen the conductor layer in dielectric constant. CONSTITUTION:An insulating layer 5 interposed between conductor layers 2 and 3 is etched using the conductor layer 3 as a mask so as to make the surfaces 2A and 3A of the conductor layers 2 and 3 exposed to air. Moreover, an insulating layer 6 interposed between the conductor layers 3 and 4 is etched through the conductor layer 4 as a mask. The insulating layer 5 and the conductive layer 3 are formed into the same shape with the insulating layer 6 and the conductive layer 4. By this constitution, the surfaces of the conductor layers 2, 3, and 4 are all exposed to air excluding their intersected part, and the conductor layers 2 and 3 are not covered with the insulating layers 5 and 6, so that the conductor layers 2 and 3 can be reduced in dielectric constant and a signal propagation speed is improved.

Description

[Detailed Description of the Invention] [Summary] Regarding a thin film substrate in which a plurality of conductor layers are laminated on a base made of a ceramic material via an insulating layer, the surface of the conductor layer is exposed to the air as much as possible to reduce the dielectric constant. The purpose of this is to improve the signal propagation speed in the conductor layer by lowering the conductor layer. A first insulating layer interposed therebetween uses the second conductive layer as a mask, and a second insulating layer interposed between the second and third conductive layers uses the third conductive layer as a mask. Each is removed by etching,
The first insulating layer and the second conductor layer are configured to have the same shape, and the second insulating layer and the third conductor layer have the same shape.

[Industrial application field]

The present invention relates to a thin film substrate in which a plurality of conductor layers are laminated on a base made of a ceramic material with an insulating layer interposed therebetween.

In recent years, as electronic computers have become faster and more sophisticated, there has been a strong demand for higher density circuit boards used in these configurations.

Therefore, for such circuit boards, patterns are formed using thin films, and high-density thin film boards are used in which layers of the pattern are insulated by insulating layers to form a multilayer structure.

[Conventional technology]

Conventionally, the structure was as shown in the conventional perspective view of FIG.

As shown in Figure 4, the base l is made of ceramic reflex material.
A first conductive layer 2 of a thin film formed by sputtering or vapor deposition of a metal as a conductive material is stretched over the surface 1A of the conductive material, and a first insulating layer 10 of an organic insulating material such as a polyimide resin material is interposed. A second conductor layer 3 made of a thin film similar to the first conductor layer 2 is stretched across the first conductor layer 2,
Furthermore, a third conductor layer 4 made of a thin film similar to that of the first conductor layer 2 is stretched across the second conductor layer 3 by interposing a second insulating layer 11 made of a similar organic insulating material. is configured to be

Therefore, it is possible to form a multilayer pattern on the base 1 by laminating the first, second, and third conductor layers 2.3.4 via the first and second insulating layers 10.11, respectively. I was worried.

Further, such lamination has been manufactured by the steps shown in the conventional manufacturing process diagrams of FIGS. 5(a) to 5(e).

As shown in FIG. 5(a), the first conductor layer 2 is laminated on the surface 1A of the base 1, and as shown in FIG. The insulating layer 10 is laminated.

Next, as shown in (c), the upper layer 1 of the first insulating layer 10 is
The second conductor layer 3 is laminated on 0A, and as shown in (d),
The second insulating layer 11 is laminated so as to cover the second conductor layer 3, and finally, a third
Manufacturing was carried out by laminating conductors in this order.

[Problem to be solved by the invention]

Such first and second insulating layers io, tt are as follows:
Usually, an inorganic insulating material such as a ceramic material or an organic insulating material such as a polyimide resin material is used.

When an inorganic insulating material is used, it has low thermal resistance as an insulator, has strong adhesion strength with the conductor layer (and has high physical strength, but has the disadvantage that the signal propagation speed is slow due to its high dielectric constant) There is.

On the other hand, when an organic insulating material is used, it is inferior to an inorganic insulating material in terms of low thermal resistance and physical strength, but because of its low dielectric constant, the signal propagation speed is moderated, and it is advantageous in terms of speeding up.

However, with the recent strict demands for higher speeds in electronic computers, the delay in signal propagation speed cannot be ignored even with insulation using organic insulating materials.

Therefore, even if insulation using an organic insulating material is used, it is required to lower the dielectric constant of the conductive layer forming the pattern and further improve the signal propagation speed.

Therefore, the present invention aims to improve the signal propagation speed by exposing the surface of the conductor layer to the air as much as possible and lowering the dielectric constant of the conductor layer.

(Means for solving problems) FIG. 1 is a diagram explaining the principle of the present invention.

As shown in FIG. 1, the surfaces 2A and 3A of the first and second conductor layers 2.3 are exposed to the air.
A first insulating layer 5 is interposed between the second and third conductor layers 3.4 using the second conductor layer 3 as a mask. The second insulating layer 6 is removed by etching using the third conductive layer 4 as a mask, and the shapes of the first insulating layer 5 and the second conductive layer 3 and the second The insulating layer 6 and the third conductor layer 4 are configured to have the same shape.

The above-mentioned problem is solved by the configuration as described in 2.

[Effect]

That is, by using the second conductor layer 3 stretched across the first conductor layer 2 with the first insulating layer 5 interposed therebetween as a mask, the first insulating layer 5 is The first conductor layer 2 can be removed by etching and exposed in the air, and the second conductor layer 2 can be stretched by interposing the second insulating layer 6 so as to cross the second conductor layer 3. By using the third conductor layer 4 as a mask, the second insulating layer 6 can be removed by etching and the second conductor layer 3 can be exposed to the air.

Therefore, the surfaces of each of the first, second and third conductor layers 2.3.4 are exposed to the air except for the intersection points, and the surfaces of the first and second conductor layers 2.3.4 are exposed to the air, unlike the conventional Compared to the configuration in which the layer 2.3 is covered by the first and second insulating layers 10.11, the dielectric constant for the first and second conductive layers 2.3 can be lowered and the signal propagation speed can be increased. Improvements can be made.

〔Example〕

The present invention will be explained in detail below with reference to FIGS. 2 and 3. FIG. 2 is a perspective view of an embodiment according to the present invention, and FIG. 3 (a) to axis) are manufacturing process diagrams of the present invention. Like numbers refer to like objects throughout the design.

As shown in FIG. 2, a first conductor layer 2 stretched over the surface 1A of the base made of a ceramic material has a second conductor layer 3 intersecting with the first insulating layer 5. Further, a third conductor layer 4 is stretched across the second conductor layer 3 with a second insulating layer 6 interposed therebetween, and the shape of the first insulating layer 5 is The configuration is such that the second insulating layer 6 has the same shape as the second conductor layer 3, and the second insulating layer 6 has the same shape as the third conductor layer 4.

Therefore, the surface 2A of the first conductor layer 2 is exposed to the air except for the portions where it intersects with the second conductor layer 3, and the surface 2A of the second conductor layer 3 is exposed to the air at the portions where it intersects with the third conductor layer 4. The surface 3A is exposed to the air except for the surface 3A.

Therefore, since the first and second conductive layers 2.3 are not covered by the first and second insulating layers 5.6, the dielectric constants of the first and second conductive layers 2.3 are can be lowered.

Moreover, such lamination can be easily performed by the manufacturing process shown in FIG.

As shown in FIG. 2(a), a first conductive layer 2 is formed on the surface 1A of the base l, and as shown in FIG. 2(b), a first insulating layer is formed to cover the first conductive layer 2. , the image layer 5 is laminated.

In this case, the first insulating layer 5 is laminated by, for example, applying a polyimide resin solution to a predetermined thickness and curing it.

Next, as shown in (c), the upper layer 5A of the first insulating layer 5 is
A second conductor layer 3 is formed, and as shown in (d), the first insulating layer 5 is removed by wet etching or dry etching using the second conductor layer 3 as a mask. The first insulating layer 5 is made to remain only directly below where the first insulating layer 3 is stretched.

Furthermore, as shown in (e), the second insulating layer 6 is laminated to cover the entire surface in the same manner as the first insulating layer 5 described above, and the upper layer of the second insulating layer 6 is laminated. 6A, as shown in (f), a third conductive layer 4 is formed, and the second insulating layer is removed using the third conductive layer 4 as a mask in the same manner as the removal of the first insulating layer 5 described above. By removing the layer 6, the second insulating layer 6 can be formed so as to remain only directly under the stretched third conductor layer 4, as shown in (g).

When formed in this way, the first layer is laminated on the surface 1A of the base l. All surfaces 2A, 3A, 4A of the second and third conductor layers 2.3.4 will be exposed to the air, unlike conventional conductor layers that are all buried in an insulating layer. It is clear that the dielectric constant for the conductor layer is lower in comparison.

Therefore, the signal propagation speed in each conductor layer can be increased.

In addition, in the present invention, the first. Second and third conductor layers 2.3.
Although the explanation was given by laminating 4, the fourth and fifth conductor layers can be formed by further interposing the third and fourth insulating layers on top of the third conductor layer 4 through similar lamination. A similar structure can be achieved even when formed in a laminated manner, and even in this case, the same effect can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, an insulating layer stacked between conductor layers can be removed using the upper conductor layer as a mask, thereby exposing the surface of a predetermined conductor layer to the air. can.

Therefore, it is possible to lower the dielectric constant of the conductor layer and improve the signal propagation speed, which has a great practical effect, especially in electronic computers that require high speed.

FIG. 4 is a conventional perspective view.

FIGS. 5(a) to 5(e) show conventional manufacturing process diagrams.

In the figure, ■ is the base, 2 is the first conductor layer.

3 is the second conductor layer, 4 is the third conductor layer.

5 is a first insulating layer, and 6 is a second insulating layer.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention. FIG. 2 is a perspective view of an embodiment according to the present invention. FIGS. 3(a) to 3(g) are manufacturing process diagrams of the present invention. 4 3rd '4 Salary Counterfeit g! Ij1 Diagram Part 2 ■ (3) Heather – August’s mini production schedule 6 Second grudge police Traditional autopsy map No. 4 (￥l

Claims (1)

[Claims] A first conductor layer (2) stretched over the surface (1A) of a base (1) made of a ceramic material;
) A second conductor layer (
3) and a third conductor stretched across the second conductor layer (3) with a second insulating layer (6) laminated on the second conductor layer (3) interposed therebetween. A thin film substrate comprising a layer (4), the surfaces (2A, 3A) of the first and second conductor layers (2, 3)
) of the first insulating layer (5) is exposed to the air.
) uses the second conductor layer (3) as a mask to conduct the second conductor layer (3) as a mask.
The insulating layer (6) is removed by etching using the third conductive layer (4) as a mask, and the first insulating layer (5) and the second conductive layer (3) are removed. A thin film substrate characterized in that the shape and the shapes of the second insulating layer (6) and the third conductor layer (4) are formed to be the same.