JPH0541454A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a drop in manufacturing yield due to the connection be tween each electrode and a silicon substrate induced by misregistration of a contact for interconnection and a lower layer electrode when connecting wirings on an element isolation region. CONSTITUTION:A silicon nitride film 3 covers the surface of a thick silicon oxide 2, which is a device isolation region for a semiconductor device. Even when a lower layer electrode 4 is shifted from a contact, oxide film etching required for the formation of a contact comes to a halt at the silicon nitride film 3, which prevents an upper layer electrode 6 and the lower layer electrode 4 from being connected with a silicon substrate. It is, therefore, possible to prevent a drop in manufacturing yield induced by either contact or the lower layer electrode 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a multilayer electrode, and more particularly to an element isolation region.

[0002]

2. Description of the Related Art A conventional semiconductor device will be described with reference to FIG. The element isolation region of a conventional semiconductor is a thick silicon oxide film (hereinafter referred to as an oxide film) formed by selective oxidation of the silicon substrate 1.
It was formed of 2. Then, as shown in FIG.
First, the lower layer electrode 4 was formed, and then the interlayer insulating film 5 with the upper layer was formed by the oxide film. And Figure 2
As shown in FIG. 2B, a contact for connecting the lower layer electrode 4 and the upper layer electrode 6 is formed on the element isolation region, and the upper layer electrode 6 is formed thereon, as shown in FIG. 2C.

[0003]

When forming a contact for connecting an upper layer electrode and a lower layer electrode on this conventional element isolation region, a thick interlayer insulating film between the upper layer electrode and the lower layer electrode and the element isolation region are formed. Since the insulating film is the same oxide film, the contact becomes silicon when the photoresist that serves as a mask for contact formation and the lower layer electrode are misaligned or when the oxide film for contact formation is excessively etched. There is a problem in that the substrate reaches the substrate and the upper electrode and the lower electrode are connected to the silicon substrate as shown in FIG. 4, resulting in a decrease in manufacturing yield.

An object of the present invention is to prevent each electrode from being connected to a silicon substrate due to a displacement between a contact for connection and a lower layer electrode in connection between wirings on an element isolation region, thereby improving manufacturing yield. It is to provide a semiconductor device that can be improved.

[0005]

In a semiconductor device of the present invention, a silicon nitride film (hereinafter referred to as a nitride film) is formed on a thick oxide film which will be an element isolation region in an element isolation region.

[0006]

The present invention will be described below with reference to the drawings. Figure 1
FIG. 3 is a cross-sectional view of a semiconductor device shown in order of steps for explaining an embodiment of the present invention and a manufacturing method thereof. Figure 1
As shown in (a), a thick oxide film 2 to be an element isolation region is formed by selective oxidation of the silicon substrate 1, and a nitride film layer 3 is formed thereon. Next, the nitride film is selectively etched by using the photolithography technique to leave the nitride film 3 only on the element isolation region as shown in FIG. After that, as shown in FIG. 1C, after forming an interlayer oxide film 5 between the lower electrode 4 and the upper electrode, a contact for connecting the upper electrode 6 and the lower electrode 4 is formed with a photoresist. Interlayer oxide film 5 is selectively etched and formed as a mask. Then, when the upper layer electrode 6 is formed thereon, the embodiment shown in FIG. 1D is completed.

[0007]

As described above, according to the present invention, the thick oxide film serving as the element isolation region is covered with the nitride film.
Even if the contact with the lower layer electrode is deviated as shown in FIG. 5, the oxide film etching for forming the contact does not stop at the nitride film and the upper layer electrode and the lower layer electrode are not connected to the silicon substrate. This has the effect of preventing a decrease in manufacturing yield due to a displacement between the contact and the lower layer electrode.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device shown in order of steps for explaining an embodiment of the present invention and a manufacturing method thereof.

FIG. 2 is a cross-sectional view of an example of a semiconductor element shown in the order of steps for explaining a conventional semiconductor element and a manufacturing method.

FIG. 3 is a cross-sectional view showing a case where the lower electrode and the contact are misaligned in one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional semiconductor element in which a contact with a lower electrode is displaced.

[Explanation of symbols]

 1 Semiconductor Substrate 2 Thick Silicon Oxide Film 3 Silicon Nitride Film 4 Lower Layer Electrode 5 Interlayer Silicon Oxide Film 6 Upper Layer Electrode

Claims (1)

[Claims] 1. A semiconductor device, wherein in a device isolation region of a semiconductor device having a multilayer electrode, a silicon nitride film covers a thick silicon oxide film to be the device isolation region.