JPH07106757A - Thin-film multilayered circuit board and its manufacture - Google Patents

Abstract

PURPOSE:To prevent the disconnection of a second conductor layer and the occurrence of inter-layer leakage by improving the coating state of an insulating layer formed on a first conductor layer in a thin-film multilayered circuit board constituted by forming a thin-film multilayered circuit on a glass or alumina substrate. CONSTITUTION:In a thin-film multilayered circuit board, a first-layer wiring 12 is formed as a first conductor layer by successively forming three thin films 12a, 12b, and 12c on an electrically insulating substrate 11 composed of glass and an layer insulating film 13 and second-layer wiring 14 are successively formed on the wiring 12 as an insulating layer and second conductor layer, respectively. The widths of the thin films 12a, 12b, and 12c are reduced as going toward the topmost layer 12c so that steps can be formed on the outer peripheral surface of the wiring 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film multilayer circuit board used in various consumer electronic devices and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and speeding up of computer equipment, circuit boards used therein are required to have finer wiring dimensions and multilayer wiring.

A conventional thin film multilayer circuit board will be described below with reference to the drawings. FIG. 3 is a sectional view of a conventional thin film multilayer circuit board. As shown in FIG. 3, the thin-film multilayer circuit board comprises a first conductive layer 1 which is a first conductor layer on an electrically insulating substrate 1 made of glass, and an insulating layer 3 on the first conductive layer 2.
And the second-layer wiring 4, which is the second conductor layer, is provided on the insulating layer 3.

[0004]

SUMMARY OF THE INVENTION In the above conventional configuration,
The first layer wiring 2 is a single layer formed by dry etching,
The outer peripheral surface 2a is substantially perpendicular to the upper surface of the electrically insulating substrate 1. Therefore, when the insulating layer 3 is formed on the first-layer wiring 2, the insulating layer 3 is in the overhang state 3a outside the first-layer wiring 2, and the second-layer wiring 4 is formed on this.
Is formed, in the portion of the overhang state 3a, the second
The layer wiring 4 is broken, and the thickness of the insulating layer 3 becomes thin.
There is a problem that a leak occurs between the layer wiring 2 and the second layer wiring 4.

An object of the present invention is to prevent the above disconnection and leakage.

[0006]

In order to achieve the above object, in the thin film multilayer circuit board of the present invention, the first conductor layer laminated on the electrically insulating substrate has a large number of widths from the lower layer to the upper layer. The thin film of is laminated stepwise.

[0007]

With the above structure, the outer peripheral surface of the first conductor layer on the electrically insulating substrate is stepped, and the angle on the electrically insulating substrate is obtuse, so that the insulating layer is formed on the first electrically conductive layer. However, the overhang state does not occur even if the wire is formed, and as a result, the wire breakage of the second conductor layer and the first and second
It is possible to prevent the occurrence of leakage between the conductor layers, and it is possible to form a highly reliable multilayer wiring board.

[0008]

(Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a thin film multilayer circuit board showing an embodiment of the present invention. As shown in FIG. 1, the thin-film multilayer circuit board is formed on the electrically insulative substrate 11 made of glass.
CuNi thin films 12a, 1 having a layer thickness of 0.8 μm
2b and 12c are laminated to form a first conductor layer, a first-layer wiring 12, an interlayer insulating film 13 having a thickness of 1.5 μm on the first-layer wiring 12, and a thickness on the interlayer insulating film 13. 2 μm C
It is configured by laminating the second layer wiring 14 in which u is the second conductor layer. The first layer wiring 12 includes thin films 12a, 12b,
12c is formed by sequentially stacking the lower layers from the lower layer to the upper layer. Since the width of the thin films 12a to 12c is sequentially reduced, the first layer wiring 12 formed by the stacked thin films 12a, 12b and 12c is formed. The outer peripheral surface is stepped.

The features of the thin-film multilayer circuit board having the above structure will be described below. The first layer wiring 12 laminated on the electrically insulating substrate 11 is a multilayer thin film 12a, 12
b, 12c are laminated to form a first
Since the outer peripheral surface of the layer wiring 12 is formed stepwise, the cross-sectional shape of the one-layer wiring 12 becomes a trapezoid whose side edges are stepwise, and the angle A with the upper surface of the electrically insulating substrate 11 is an obtuse angle. Even if the interlayer insulating film 13 is formed on the first layer wiring 12, the overhang state can be prevented from occurring.

As described above, according to the first embodiment of the present invention, since the overhang state does not occur on the first layer wiring 12 on the electrically insulating substrate 11, the interlayer insulating film is formed on the first layer wiring 12. 13 and the second layer wiring 14 are formed, the second
It is possible to prevent the disconnection of the layer wiring 14 and the occurrence of leakage between the first layer wiring 12 and the second layer wiring 14 without reducing the thickness of the interlayer insulating film 13.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view of a thin film multilayer circuit board according to the second embodiment. As shown in FIG. 2, the structure of the thin film multilayer circuit board is substantially the same as that of the thin film multilayer circuit board in the first embodiment, and the thin films 12d, 1 made of CuNi are formed.
The thickness of 2e and 12f is 0.8μm and 0.6μ, respectively.
m, 0.4 μm.

The characteristics of the thin-film multilayer circuit board having the above structure will be described below. Since the thickness of the multi-layered thin films 12d, 12e, 12f forming the first-layer wiring 12 is smaller in the upper layer, the angle A between the side edge of the cross section of the first-layer wiring 12 and the upper edge of the electrically insulating substrate 11 is further increased. More obtuse angle, first
When the interlayer insulating film 13 is formed on the layer wiring 12, the inclination of the interlayer insulating film 13 can be made gentler to prevent the overhang state from occurring as much as possible. As described above, according to the second embodiment of the present invention, the effect of the first embodiment can be further enhanced, and even if the interlayer insulating film 13 and the second layer wiring 14 are formed on the first layer wiring 12. The disconnection of the second layer wiring 14 and the thickness of the interlayer insulating film 13 do not become thin, and the first layer wiring 12
It is possible to prevent the occurrence of leakage between the second layer wiring 14 and the second layer wiring 14 as much as possible.

The thickness of the multi-layered thin film forming the first-layer wiring 12 is the same as that of the lower-layered thin film, if timely combined in consideration of the occurrence of an overhang condition. Can be obtained.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of the thin film multilayer circuit board described in the first embodiment of the present invention. As shown in FIG. 1, in the manufacturing process of the thin film multilayer circuit board, the thin film 1 made of CuNi having a thickness of 0.8 μm is formed on the electrically insulating substrate 11 made of glass.
2a, 12b, 12c are more thin film 12 than thin film 12a
b, the first step of sequentially laminating the thin film 12c from the lower layer to the upper layer so that the thin film 12c has a larger Ni addition amount than the thin film 12b, and the thin films 12a, 12b, 12
The second step of etching c to form the first-layer wiring 12 and 1.5 μm on the first-layer wiring 12 by the P-CVD method.
a third interlayer insulating film 13 formed of a SiON film of m.
And the fourth step of forming the second layer wiring 14 of Cu having a thickness of 2 μm on the interlayer insulating film 13 by sputtering.

The characteristics of the method of manufacturing the thin-film multilayer circuit board having the above structure will be described below. First layer wiring 1
When the conductor layer 2 is formed by the three thin films 12a, 12b, 12c, the thin films 12a, 12b, 12c are adjusted so that the etching rate is different by adjusting the addition amount of Ni of CuNi.
In addition, since the thin films 12a, 12b, and 12c are laminated from the lower layer to the upper layer in order from the lower layer, the wet etching is performed once, the cross-sectional shape of the first-layer wiring becomes a trapezoid with side edges stepwise. Can be formed.

As described above, according to this embodiment, when forming the first-layer wiring 12, thin films having different etching rates are laminated. Therefore, if the wet etching is performed once, the cross-sectional shape of the first-layer wiring 12 is changed to the side. The sides can be formed in a stepped rectangle, and the manufacturing process can be simplified.

In this embodiment, as the thin film having a different etching rate, the one in which the addition amount of Ni of CuNi is adjusted is used, but the same effect can be obtained by using a thin film made of a material having a different etching rate.

(Embodiment 4) A fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view of the thin-film multilayer circuit board described in the second embodiment of the present invention. As shown in FIG. 2, the manufacturing process of the thin film multilayer circuit board is substantially the same as the manufacturing process of the thin film multilayer circuit board in the third embodiment, and in the first step, a C film having a thickness of 0.8 μm is used.
A thin film 12d made of uNi and CuN having a thickness of 0.6 μm
a thin film 12e made of i and a thin film 12f made of CuNi having a thickness of 0.4 μm,
This structure has a step of forming the first layer wiring 12 by sequentially stacking from the lower layer to the upper layer by sputtering such that the amount of Ni added to the thin film 12f is larger than that of the thin film 12e.

The characteristics of the method of manufacturing the thin-film multilayer circuit board having the above structure will be described below. First layer wiring 1
Since the thin films 12d, 12e, and 12f forming 2 are thinner in the upper layer and have a higher etching rate, the time for etching the upper thin film 12f having a large etching amount can be shortened when etching is performed. ,
If the wet etching is performed once, the cross-sectional shape of the first layer wiring 12 can be formed in a trapezoidal shape whose side edges are stepwise.

As described above, according to this embodiment, in addition to the effects of the third embodiment, when the first layer wiring 12 is formed, the time for etching the upper layer thin film 12f, which has a large etching amount, is shortened. As a result, it is possible to reduce the time in the etching process, simplify the manufacturing process, and shorten the manufacturing time.

[0024]

As described above, according to the present invention, the first conductor layer formed on the electrically insulating substrate is formed of a multi-layered thin film, and the outer peripheral surface of the first conductor layer is formed into a stepwise shape. Even if the insulating layer is formed on the conductor layer, the insulating layer becomes gentle, the overhang state does not occur, and the disconnection of the second conductor layer and the occurrence of leakage between the first and second conductor layers occur. It is possible to form a highly reliable multilayer wiring board which can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a thin film multilayer circuit board according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a thin film multilayer circuit board according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional thin film multilayer circuit board.

[Explanation of symbols]

 11 Electrical Insulating Substrate 12 First Layer Wiring 12a Thin Film 12b Thin Film 12c Thin Film 13 Interlayer Insulating Film 14 Second Layer Wiring

Claims (4)

[Claims] 1. An electrically insulating substrate, a first conductor layer laminated on the substrate, an insulating layer laminated on the first conductor layer, and a second conductor layer laminated on the insulating layer. Has and
The first conductor layer is a thin-film multi-layer circuit board formed by stacking a number of thin films, the width of which is gradually reduced from a lower layer to an upper layer, in a stepwise manner. 2. The thin-film multilayer circuit board according to claim 1, wherein the thickness of the thin film is successively reduced from the lower thin film to the upper thin film. 3. A first step of laminating a first conductor layer on an electrically insulating substrate, a second step of laminating an insulating layer on the first conductor layer, and a second step on the insulating layer. A third step of stacking two conductor layers, the first step of the first step
The conductive layer is formed by sequentially stacking thin films having a higher etching rate from a lower layer to an upper layer, and then, after stacking the thin films, a multilayer thin film is formed by a method for manufacturing a thin film multilayer circuit board. 4. The method for manufacturing a thin-film multilayer circuit board according to claim 3, wherein the thickness of the lower-layer thin film is successively reduced to the upper-layer thin film.