JPS5915178B2 - Wiring structure and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optimal wiring structure and method for use in semiconductor ICs, hybrid thick film ICs, and the like.

Semiconductor IC) In hybrid thick film ICs, etc., 2
It is often the case that two conductors are electrically insulated from each other and crossed with an insulator interposed between them.

↓In such cases, structures shown in FIGS. 1 and 2, for example, have been conventionally used. 1 and 2 are enlarged views of the main parts of the IC pellet 1. FIG.

An insulating layer 3 such as SiO2 is formed on the upper surface of a base 2 of the pellet 1 made of a semiconductor such as Si or an insulator such as ceramic. Furthermore, on the upper surface of this insulating layer 3, a first conductor 4 and a second conductor 5 made of Al, Au, etc. are deposited by vapor deposition, sputtering, etc., with an insulator 6 made of SiO2 interposed therebetween. They are formed by crossing each other. In such a structure, the first conductor 4 and the second conductor 10-layer body 5
The problem is the stray capacitance that occurs between the two. In order to reduce this stray capacitance, as shown in the figure, the width of the intersection of the first and second conductors 4 and 5 is made smaller, and the thickness tl of the insulator 6 is increased. 15 by increasing the insulation distance between them. In addition, the first and second conductors 4
, 5 are formed by vapor deposition or the like substantially perpendicularly from the direction of arrow T in FIG. Since the adhesion force due to vapor deposition becomes weaker, the thickness is reduced by 20 mm. Therefore, these portions 5a and 5b are insulators 6
The larger the thickness tl becomes, the more difficult it becomes to deposit, and the thickness becomes even thinner, making pinholes and the like more likely to occur. Therefore, in the conventional wiring structure, the second conductor 5
There were cases where poor conductivity, disconnections, etc. occurred. Note that under general conditions, the thickness tl of the insulator 6 is 600 mm.
It has been confirmed that when the current exceeds 0 A, parts that are likely to break the second conductor 5 begin to appear, and when the current exceeds 7000 Å, the number of parts that are likely to be cut suddenly begins to increase. -o The present invention was made in view of the above-mentioned actual situation, and its structure is such that a recess is provided at the intersection of two conductors on an insulating layer.

Further, in this method, the insulator is formed by oxidizing a metal plating layer such as copper. 5 Examples of the present invention will be described below with reference to the drawings.

3 to 5 show the manufacturing process of the wiring structure according to the present invention.

First, as shown in FIGS. 3A and 3B, a recess is formed at a predetermined depth on the upper surface of an insulating layer 3 such as SiO2 formed on a substrate 2 of a pellet 1 made of a semiconductor such as Si or an insulator such as ceramic. 7 will be provided.

Next, a first conductor 4 made of W, MO, etc. is formed in a plane including the recess 7 to a predetermined thickness and width by vapor deposition or the like.
In this case, the thickness T2'' of the first conductor 4 is formed to be smaller than the depth T3 of the recess 7. The thickness T2'' is, for example, 1000 A, and the depth T3 is, for example, 4000 A. may be used as

Next, as shown in FIGS. 4A and 4B, the first conductor 4 except for the vicinity of the recess 7 is covered with a mask 8 made of photosensitive resin or the like.

Thereafter, the pellets 1 are plated with copper by electroplating in a copper sulfate bath, a copper borofluoride bath or a copper cyanide bath.
As a result, as shown in FIGS. 5A, B, and C, a copper plating layer 6 is formed in and around the concave portion 7 of the first conductor 4 excluding the portion covered with the mask 8. . Note that the thickness T4 of this plating layer 6 may be, for example, about 6000-A.

Next, when the pellet 1 shown in FIG. 5 is left in an oxidizing atmosphere at 300 to 500 DEG C. for 1 to 2 hours, the plating layer 6 is oxidized to become copper oxide. As a result, at least a portion of this plating layer 6 becomes an insulator. Next, the mask 8 is removed, and then Au, Al, A
The wiring structure is completed by forming a second conductor 5 made of a layer 3 or a layer thereof on the insulating layer 3 and the insulator 6 to a thickness of, for example, 1000 A by vapor deposition or the like.

At this time, the second conductor 5 is formed so as to intersect with the first conductor 4 at a position corresponding to the recess 7 on the plating layer 6. According to the structure shown in FIGS. 6A and 6B, the height h of the plating layer 6 interposed as an insulator between the first and second conductors 4 and 5, which protrudes from the insulating layer 3, is The depth T3 of the recess 7 can be made lower than that shown in FIGS. 1 and 2.

Therefore, when the second conductor 5 is deposited, the adhesion force to both sides of the insulator 6 is stronger than that in FIGS. 1 and 2, and the second conductor 5 formed on both sides is stronger. The thickness of portions 5a and 5b of conductor 5 can be increased. Therefore, pinholes and the like in these portions 5a and 5b can be eliminated, and occurrences of poor conductivity, disconnection, etc. can be greatly reduced. Note that the depth T3 of the recess 7 may be approximately half the thickness T4 of the plating layer 6. Further, the thickness T4 of the plating layer 6 may be determined so that the above-mentioned protruding height h is about 6000A or less. In the wiring structure according to the present invention, a first
and a wiring structure in which the second conductors are electrically insulated and crossed with an insulator interposed between them, and a recess is formed in the insulating layer at a position corresponding to the crossing portion. The first conductor is disposed along this recess.

Further, in the wiring method according to the present invention, in the case where two conductors are wired so as to cross each other on an insulating layer so as to be electrically insulated from each other with an insulator interposed between them, the above-mentioned crossing portion of the above-mentioned insulating layer A recess is formed at a position corresponding to the recess, one conductor is disposed along this recess, a metal plating layer is formed on the conductor in the recess, and this metal plating layer is oxidized. The conductor is made of the above-mentioned insulator, and then the other conductor is arranged along the above-mentioned insulator.

Therefore, according to the present invention, the thickness of the insulator can be made substantially thinner by the depth of the recess, so that even if the conductor is formed by vapor deposition or the like, the conductor attached to both sides of the insulator is thinner. The thickness of the conductor can be made relatively large, and therefore, conductivity defects and disconnections of the conductor can be greatly reduced.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional wiring structure, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIGS. 3 to 6 are a plan view and a sectional view showing an embodiment of the present invention. In addition, in the symbols used in the drawings, 1 is the pellet, 2 is the base, 3 is the insulating layer, 4 is the first conductor, and 5 is the second conductor.
, 6 is a plating layer, and 7 is a recess.

Claims (1)

[Scope of Claims] 1. In a wiring structure in which two conductors are electrically insulated from each other and crossed on an insulating layer with an insulator interposed between them, the crossing portion of the insulating layer A wiring structure characterized in that a recess is formed at a position corresponding to the recess, and one conductor is disposed along the recess. 2. When wiring two conductors on an insulating layer so as to interpose an insulator between them so as to electrically insulate each other and cross each other, a recess is provided at a position corresponding to the crossing portion of the insulating layer. forming one conductor along the recess, then forming a metal plating layer on the conductor in the recess, and then oxidizing the metal plating layer to form the insulator; A wiring method characterized in that the other conductor is then arranged along the insulator.