JPS618951A - Wiring formation method - Google Patents

Abstract

PURPOSE:To improve the reliability of wiring, by using a common resist pattern, alternately depositing the insulating film of the first deposited film and the wiring metal of the second deposited film, performing only one lift OFF, thereby forming the wiring very simply. CONSTITUTION:A resist pattern 2 is formed on a ground layer 1, which is a substrate. The resist pattern 2 has a hole 3 corresponding to a wiring pattern in an area, where wiring is formed. On the upper side of the resist pattern 2 including the hole 3, the first deposited film, e.g., an insulating film 4, is deposited by a depositing method with less directivity. Then the second deposited film, e.g., a wiring metal, is deposited by a depositing method with high directivity. At this time, the wiring metal 5 is deposited in the vertical direction with respect to the surface of the substrate by an electron beam evaporating method as shown by wiring metal parts 5a and 5b on the insulating layer parts 4a and 4b, respectively, for example platinum is evaporated. When the resist pattern 2 is dissolved and the lift OFF is performed, the wiring metal part 5b on the insulating film 4b is formed as the metal wiring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming wiring included in a semiconductor device.

(Prior Art) Among the wiring structures of conventional semiconductor devices, there is a two-layer wiring structure. In that case, it is necessary to insulate and separate the wiring lines from each other. Therefore, in forming this two-layer wiring structure, after forming the first wiring, an insulating film is deposited on the entire surface of the wafer by CVD, and then a resist pattern is formed on this insulating film. Then, a metal layer for the second wiring is deposited, and finally the resist pattern is dissolved and removed by a lift-off method to form the second wiring.

(Problems to be Solved by the Invention) As described above, in the conventional method, when protecting the previously formed electrode wiring with an insulating film, the previously formed metal wiring, for example, the first wiring or the second wiring, It is necessary to apply an insulating film again using the CVD method on the entire surface of the sea urchin, which has
Furthermore, since the insulating film adheres to unnecessary areas, a new etching process is required to remove it.

The first object of the present invention is to provide a wiring forming method that can easily form an insulating film only in the necessary portion directly under the wiring by a single lift-off process.

A second object of the present invention is to provide a wiring forming method that easily obtains wiring protected by an insulating film through a single lift-off process.

(Means for Solving the Problems) In order to achieve this object, in the present invention, a resist pattern having a cross-sectional shape in which the width of the opening of the hole is narrower than the width of the bottom is used as a base layer. 1°: **
t6I! 1. ! -,,: A step of applying a @-adhesive film on the upper side of the pass H°'addition pattern using a less directional deposition method, and a second coating using a highly directional deposition method. It is characterized by including a step of depositing a deposited film, and a lift-off step of dissolving and removing the resist pattern described above to form wiring.

(Function) According to such a method, after the insulating layer of the first deposited film and the wiring metal of the second deposited film are alternately and sequentially deposited using a common resist pattern, the -turn lift-off is performed. Since it is only necessary to perform the following steps, the wiring can be formed much more easily than the conventional method.

Wiring and insulating layers can be formed with dimensions regulated by the hole dimensions of the resist pattern, weakly directional deposition methods, and strong directional deposition methods, making it possible to significantly improve the reliability of the wiring compared to conventional methods. .

(Example) The present invention will be described in detail below with reference to one drawing.

1 = JJJ.

FIG. 1 (1) to (It) are. . invention. The first example will be explained.
1f is a cross-sectional view for clarity, and the hole portion shows a cross section.

First, a resist pattern 2 is formed on the base layer 1 by a conventional method to a thickness of, for example, about tp. In this case, the base layer 1 is, for example, a substrate. This resist pattern 2 has holes 3 in a pattern corresponding to the wiring pattern in an area where wiring is to be formed. This hole 3 has a width W1 at its mouth narrower than a width W2 at its bottom, and has, for example, a reverse tapered cross-sectional shape.

Next, as shown in FIG. 1(B), the upper side of the resist pattern 2 including the holes 3 is coated with a less directional coating method.
A first deposited film, for example an insulating film 4, is deposited. This insulating film 4 is attached to the surface of the resist pattern 4 (this insulating layer portion is shown as 4a), and the substrate l which is the bottom of the 63
(this insulating layer portion is shown as 4b). In this case, the insulating film 4 is formed by depositing a silicon oxide film having a thickness of, for example, about 1000 to 5000 Å using a sputtering method.

Next, as shown in FIG. 1C, a second deposited film, for example, a wiring metal, is deposited using a highly directional deposition method. In this case, for example, platinum is deposited as the wiring metal 5 from a direction perpendicular to the substrate surface using an electron beam evaporation method, thereby depositing the wiring metal parts 5a and 5b on the insulating layer parts 4a and 4b, respectively. . Due to the strong directivity of the electron beam, this platinum is limited by the edge of the insulating layer 4a corresponding to the mouth of the hole 3, and is applied to the wiring metal 5 on the insulating layer 4b.
b, but the central part of resist pattern 2,
Therefore, it is deposited on the insulating layer 4b at approximately the center of the hole 3, and does not adhere to the walls of the hole.

Next, as shown in FIG. 1(It), when the resist pattern 2 is dissolved and lift-off is performed, the wiring metal portion 5b on the insulating film 4b is formed as a metal wiring, so that the resist pattern 2 is completely removed.
Metal wiring located in a self-aligned manner on b is obtained.

1; 1 difference 1 Next, a second embodiment of the present invention will be described with reference to FIGS. 2(A) to (Il). In addition, in these figures, the first
Components that are the same as those shown in the figures are indicated by the same numbers, and the difference between the first and second embodiments is that the order of formation of the insulating layer and the wiring metal is reversed. Since the other points are the same, detailed explanation thereof will be omitted.

As shown in FIG. 2(A), after forming a resist pattern 2 having holes 3 similar to those in the first embodiment on a substrate as a base layer 1, first, a highly directional deposition method is applied. For example, the wiring metal 5 (5a,
As step 5b), platinum is deposited on the substrate 1 from a direction perpendicular to the substrate surface.

At this time, due to the strong directivity of the electron beam evaporation method and the reverse tapered shape of the resist pattern 2, the wiring metal 5 does not adhere to the wall portion of the 63, as shown in FIG. 2(B). , is deposited on the surface of the resist pattern 2 as a wiring metal portion 5a, and is also deposited on the surface of the substrate l in the hole 3 as a wiring metal portion 5b.

Next, as shown in FIG. 2(C), when a silicon oxide film is deposited as an insulating film 4 by a deposition method 1 with low directivity, such as sputtering, the silicon oxide film has weak directivity, so this silicon oxide film can be used as a resist. 4b also in hole 3 of pattern 2
It is deposited uniformly as an insulating layer part as shown in
An insulating layer portion as shown by 4a is also deposited on the wiring metal portion 5a outside the hole 3.

Subsequently, when lift-off is performed by dissolving the resist pattern 2, a metal wiring consisting of the wiring metal portion 5b as shown in FIG. is obtained.

In each of the above-described embodiments, the cross-sectional structure of the hole 3 is inversely tapered, but the cross-sectional shape of the hole 3 can be changed, for example, through a hole in a resist pattern on which an insulating film such as a silicon oxide film is deposited. It is also possible to have an inverted trapezoidal shape with a two-layer structure obtained by under-etching. In that case too,
Since the width of the opening of the hole is narrower than the width of the bottom of the hole, metal wiring can be formed in a self-aligned manner as in the case of Example t:1 described above.

Furthermore, by alternately stacking insulating layers and wiring metals using the same resist pattern, a multilayer wiring structure can be formed in a single lift-off process.

(Effects of the Invention) As is clear from the above description, in the method of the present invention, the mouth of the hole in the resist pattern is formed through the hole, which is narrower than the bottom, using a less directional deposition method. After depositing the insulating layer of the deposited film, if a highly directional deposition method is used to deposit the wiring metal of the second deposited film, it is possible to deposit the wiring metal of the second deposited film in a single lift-off process using a common resist pattern. , it is possible to easily form a metal wiring on the insulating film with an appropriate margin, that is, with a width slightly narrower than the width of the insulating film.

Therefore, according to the present invention, cross wiring with other wiring can be performed in an extremely simple process, and can be used, for example, in manufacturing ICs and LSIs that require insulated crossing of many wirings. I can do it.

In addition, in the method of the present invention, after the wiring metal is deposited by electron beam evaporation, which is a highly directional deposition method, an insulating layer is deposited by sputtering, which is a weakly directional deposition method, and lift-off is performed. Since it is possible to obtain a wiring structure in which the wiring metal is covered with an insulating film having a width defined by the width of the bottom of the hole in the resist pattern in a self-aligned manner, the reliability of the wiring is significantly higher than that of conventional methods. improves. Furthermore, the method of the present invention does not require a new step of attaching an insulating film when insulating and intersecting other wirings, so there is an advantage that the cross-wiring process can be shortened.

[Brief explanation of the drawing]

FIGS. 1(A) to (D) and FIGS. 2(A) to (D) are process charts for explaining the present invention in detail, respectively. 1... Base layer, 2... Resist pattern 3... Hole, 4... Insulating layer 4a, 4b
...Insulating layer portion, 5...Wiring metal 5a, 5b...
・Wiring metal part. Beko (%, +S+ 1F ~ 1
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to * , -to, /1\ 〈 = zuhe
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Claims (1)

[Claims] 1. A step of forming a resist pattern having a cross-sectional shape in which the mouth of the hole is narrower than the width of the bottom on the base layer; , a step of depositing a first deposited film using a less directional deposition method, a step of depositing a second deposited film using a highly directional deposition method, and dissolving and removing the resist pattern. and a lift-off step of forming the wiring. 2. The first deposited film is an insulating film, the second deposited film is a wiring metal, and the step of depositing the insulating film is followed by the step of depositing the wiring metal. A wiring forming method according to claim 1. 3. The first deposited film is an insulating film, the second deposited film is a wiring metal, and the step of depositing the wiring metal is followed by the step of depositing the insulating film. A wiring forming method according to claim 1.