JPS58145146A - Multilayer wiring - Google Patents

Abstract

PURPOSE:To prevent the generation of protrusions on a conductor wiring as well as to prevent the short-circuit between conductor wiring layers by a method wherein, after the prescribed first wiring pattern has been provided on the conductor using Al, an insulating layer is formed by thinly oxidizing the surface of the conductor, and the second conductor wiring is provided in the same manner. CONSTITUTION:Al, as the first wiring layer, is coated on the whole surface of a semiconductor substrate 1 and after the first wiring layer has been formed by performing an etching so as to obtain the wiring in prescribed measurements, a thin oxide film 7 of 1mA/cm<2> in current density and 500-1,000Angstrom or thereabout in thickness is formed on the wiring using an ammonium borate (NH4)3BO4 solution and the like. Then, an SiO2 film of 4,000Angstrom or thereabout is formed by performing a CVD method, and the second conductor wiring 7 is provided. As for the second wiring, the process same as the first wiring may be performed if necessary. The formation into a particle state of Al, which is the wiring material of said multilayer wiring, is not generated at all even when a heat treatment at 450 deg.C or 490 deg.C is performed, and the breakdown of the insulating layer caused by an Al protrusion, the damage by burning of the wiring and the like due to electrostatic concentration and the like are not generated at all, thereby enabling to obtain an excellent multilayer wiring in high productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to interconnects for semiconductor devices, and particularly to multilayer interconnects in which conductor interconnects used in integrated circuits and the like are stacked and separated by insulators.

The structure of a semiconductor integrated circuit (hereinafter referred to as IC).

In order to increase the degree of integration, more multi-layer wiring is now required. Normally, multilayer wiring is used by overlapping an insulating layer with an insulating material deposited on the conductor wiring, but for the reasons mentioned above, there are parts where the wiring inevitably intersects through the upper and lower layers of insulating material. I'll come. At this time, as a wiring issue, smoothness of the conductor is required. For example, wiring materials and (-) aluminum (Al) are generally widely used because they have excellent electrical conductivity, good workability, and are inexpensive as materials.

However, A7 is weak in heat resistance, and if there is a reaction with it, the M1 process will generate protrusions due to the presence of particles, and this will cause the insulation provided between the AQ layers. 1
! ! A(!l- This may cause damage, and the electric field may concentrate on the protrusion, causing the conductor itself to burn out.

The thickness of this protrusion varies depending on the heat treatment temperature, but 19
For example, at 450° C., the maximum diameter is 2 μm, which reaches 3 μm diameter at 490C, and if the wiring is thin, good characteristics cannot be obtained due to this. For example, next we will explain multi-eye self-purification of a field effect transistor.

Figure 1 shows the source electrode and gate 'flU!' of a conventional field effect transistor. and a part of the drain electrode, (a) is its oblique view, (bl is its multilayer arrangement &!
It shows a cross-sectional view of the part.

As shown in FIG. 1(a), a field effect transistor has a gate 2, a source 3, and a drain 4 formed as conductive wiring on a semiconductor substrate 1, where the gate 2 and the source 3 intersect. A crossover portion (crossover) 5 inevitably occurs on the wiring. This crossing portion 5 is shown in its entire cross-sectional view in FIG. 2B, and silicon dioxide (5io2) 6'r is provided between the gate wiring #2 and the source wiring 3 for interlayer insulation. At this time, if a protrusion occurs in the gate wiring 2, 5102 is broken and is in the upper layer.
This may interfere with the source wiring 3 and cause the field effect transistor to lose its function. Also, the variation in wiring shape is p1
It is a hindrance to productivity.

An object of the present invention is to provide a multilayer wiring which prevents the occurrence of protrusions on conductor wiring as described in 11 above and prevents short circuits between conductor wiring layers.

According to the present invention, after a first predetermined wiring pattern is provided using Al as a conductor, the exposed surface of the conductor is positive!
! A multilayer wiring is obtained, which is characterized in that the surface of the conductor is thinly oxidized by an oxidation method, and then an insulating layer and a second conductor wiring are provided in the same manner as described above.

Next, the present invention will be explained with reference to FIG. 2, together with an embodiment of the manufacturing method.

FIG. 2 shows a cross-sectional view of a multilayer wiring obtained according to the present invention.

First, Al is deposited on the entire surface of the semiconductor substrate 1 as a first wiring layer, and after etching to a predetermined wiring strength, the wiring is coated with ammonium borate (NH4) a B.
500 to 1 at a current density of 1 m and 4 d using a 04 fusing etc.
An oxide film 7 as thin as otioX is provided. Next, SiO2
iS102icVD (Che Vapor Depos
4000A is formed by the second conductor distribution method. The second conductor wiring can be subjected to the same treatment as the first wiring, if necessary.

Particle formation of Al, which is the first wiring material of the multilayer wiring provided as described above, does not occur even after heat treatment at 450°C and further at 490°C. Defects such as burnout of wiring do not occur at all, and good-looking multilayer wiring can be obtained with high productivity.

Although the present invention has been described in the case of multilayer wiring of field effect transistors, the effects of the present invention are applicable even when the type of substrate and the type of insulator provided in contact with the wiring, and even when the number of conductor wiring increases over time. obtained in the same way.

[Brief explanation of the drawing]

Figure 1 (&) is a perspective view showing an example of multilayer wiring;
b) shows its cross-sectional view, and FIG. 2 shows a cross-sectional view of the multilayer wiring obtained by the present invention. In the figure, 1 is the substrate, 2 is the first conductor wiring, and 3 is the second conductor wiring. Conductor wiring, 6 is an insulator, and 7 is an oxide film of the conductor. Teens! 1i 1 person 11 buried earth Susumu Uchihara ¥1 diagram

Claims (1)

[Claims] A multilayer wiring in which a large number of conductor wirings are separated by an insulator on a substrate, characterized in that the insulator that isolates all the conductor wirings is a chloride of a conductive material constituting all of the conductor wirings. multilayer wiring.