JPH03276631A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To control the remarkable protrusion of an overlapping part of a first metal wiring and a second metal wiring, and improve the step coverage of a protective film of this part, by a method wherein, at an intersecting part of the first and the second metal wirings, the film thickness of at least one of the metal wirings is thinly formed. CONSTITUTION:After a first metal wiring 13 is formed, a photoresist mask 1 is patterned by using a negative-positive inversion mask for patterning a second metal wiring, and a part of the first metal wiring 13 is etched halfway. After the photoresist mask 1 is exfoliated, an interlayer insulating film 2 is deposited by CVD method, and through holes 3 are formed at necessary parts. Second metal wiring material is deposited by sputtering method, and a second metal wiring 4 is patterned. Finally, a protective film 5 is deposited by CVD method.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a semiconductor device having fine two-layer metal wiring and a method for manufacturing the same.

Conventional technology Semiconductor devices are constantly evolving toward higher integration, but recently there has been a strong demand for higher speed and higher functionality of devices.For this reason, two-layer metal wiring formation technology is extremely important. - There are two main methods for forming two-layer metal interconnections: etch-back of the insulating film, and 5O
There are two methods using G (spin-on glass).

The configuration will be explained below with reference to FIGS. 3 and 4. FIGS. 3(a) to 3(e) show cross-sectional process diagrams in forming two-layer metal wiring by the etch-back method. As shown in Figure (a), a first metal wiring material is deposited on the insulating film 12 on the semiconductor substrate 11 by sputtering, and the first metal wiring 13 is patterned, as shown in Figure (b). An insulating film 14 is deposited by CVD method on
A photoresist film 15 is spin-coated. Next, the same figure (C)
RIE (reactive ion etching) as shown in
Then, as shown in FIG. 3(d), an insulating film 16 is deposited using a CVD method to form a through hole 17, and then a second metal wiring material is deposited using a sputtering method. 2. Patterning of the metal wiring 18 is performed.

Finally, a protective film 19 is deposited by the CVD method, as shown in FIG. 4(e). Next, FIGS. 4(a) to 4(d) show cross-sectional process diagrams in forming two-layer metal wiring by the SOG method. Since FIG. 3(a) is exactly the same as FIG. 3(a), the same reference numerals are given and the explanation will be omitted. Next, as shown in FIG. 4B, an insulating film 21 is deposited by CVD, and an SOG film 22 is spin-coated. After drying and vitrifying the SOG film, an insulating film 23 is deposited by CVD as shown in FIG. 2. Patterning of the metal wiring 25 is performed. Finally, a protective film 26 is deposited by CVD as shown in FIG. 2D.

Problems to be Solved by the Invention In such conventional semiconductor devices, the areas where the first metal wiring and the second metal wiring overlap are sufficiently planarized by the etch-back method, but the areas where the first metal wiring and the second metal wiring overlap are also flattened. A thick interlayer insulating film is formed between the second metal wiring and the semiconductor substrate, making it difficult to form a contact hole from the second metal wiring to the semiconductor substrate.
The overlapping part of the first metal wiring and the second metal wiring in the spin-on glass (spin-on glass) method becomes bulky and bulges upwards, which worsens the step coverage of the upper protective film and causes reliability problems. It's easy to do.

The present invention solves the above problems, and aims to provide a highly reliable small-sized semiconductor device and a method for manufacturing the same.

Means for Solving the Problems In order to achieve the above object, the present invention provides a first metal wiring and a second metal wiring formed on one main surface of a semiconductor substrate with an interlayer insulating film having at least a through hole in between. In a semiconductor device having wiring, at least one of the aforementioned metal wirings has a thinner film thickness at a location where the first metal wiring and the second metal wiring intersect.

Effect of the Invention With the above-described configuration, the present invention eliminates extreme swells of the second metal wiring at the intersections of the first metal wiring and the second metal wiring, making it possible to form a relatively flat protective film. In addition, the formation of a thick glabellar insulating film between the second metal wiring and the semiconductor substrate, which was a drawback of the conventional etch-back method, is no longer necessary, and it is now possible to form contact holes from the second metal wiring to the substrate. Become.

EXAMPLE Hereinafter, an embodiment of the present invention will be described using FIGS. 1 and 2, and the same parts as in FIGS. 3 and 4 of the conventional example will be given the same numbers, explanations will be omitted, and the present invention will be explained. We will explain the distinctive parts. That is, FIG. 1 and FIG. 2(a)
After forming the first metal arrangement 13 in FIG. 2(b)
As shown in Figure (C), the photoresist film 1 is patterned using a negative-positive reversal mask of the second metal wiring patterning mask, and as shown in Figure (C), the first metal wiring 1
Etch part of 3 halfway. After peeling off the photoresist film 1, a glabellar insulating film 2 with a thickness of 0.2 μm is deposited using the CVD method, and through holes 3 are formed at necessary locations, as shown in FIG. Furthermore, as shown in FIG. 4E, a second metal wiring material is deposited to a thickness of 0.8 μm by sputtering, and the second metal wiring 4 is patterned. Finally, as shown in Figure 1), 2N@5 is deposited by CVD. In this embodiment, a case has been described in which the thickness of the first metal wiring is made thin, but it is also possible to make the thickness of the second metal wiring thin, or both can be made thin.

Effects of the Invention As is clear from the above embodiments, according to the present invention, the first
A significant bulge in the overlapping portion of the metal wiring and the second metal wiring is suppressed, and the protective film step coverage in this portion is improved. In addition, it is now possible to easily form a contact hole from the second metal wiring to the semiconductor substrate, which was difficult with conventional two-layer metal wiring formation technology, and the degree of freedom in chip layout has been improved, resulting in compact and highly reliable semiconductor devices and A manufacturing method thereof can be provided.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of a semiconductor device according to an embodiment of the present invention;
Figures 2(a') to (f) are cross-sectional process diagrams for explaining the manufacturing process of the same semiconductor device, and Figures 3(a) to (e) and 4(a) to (d) are conventional Etchback method and S
FIG. 3 is a cross-sectional process diagram for explaining a method for manufacturing a semiconductor device by the OG method. 2...Interlayer insulating film, 3...Through hole, 4...Second metal wiring, 5...Protective film, 11... Semiconductor substrate, 12... Insulating film, 13... First metal wiring.

Claims (2)

[Claims] (1) A first metal wiring and a second metal wiring are formed on one main surface of a semiconductor substrate so as to intersect with each other with an interlayer insulating film in between, and at an intersection of the first and second metal wiring, A semiconductor device in which at least one of the metal interconnections has a thin film thickness. (2) forming a first metal wiring on one principal surface of the semiconductor substrate; forming a portion of the first metal wiring that intersects with a second metal wiring or a through hole in an interlayer insulating film of the first metal wiring; manufacturing a semiconductor device, comprising: etching away a portion to be connected to a second metal wiring through the film to reduce the film thickness; forming the second metal wiring; and forming a protective film. Method.