JPS59148340A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To make width of a wiring pattern more minute, by providing a window in an insulating film on a substrate, forming first and second conductive layers so as to cover said window, and etching away the first conductive layer, with the second conductive layer as a mask. CONSTITUTION:On an integrated circuit substrate 11, on which source and drain regions are formed by a diffusion process, a conductive metal film 12 is formed by a sputtering method. As the metal film 12, tungsten, molybdenum, or the like is used. Then, an aluminum layer is formed by a sputtering method, and an aluminum electrode 14 and a circuit pattern are formed by mask alignment. Thereafter the aluminum layer is etched, and the metal film 12 is further etched with the aluminum electrode 14 and the aluminum wiring as a mask. When the aluminum layer is etched, the source or drain n<+> layer is not etched because the surrounding part of an electrode window is coated by the metal film 12 having selectively with respect to aluminum etchant.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a semiconductor device which is effective for high integration by forming a conductive metal layer on an electrode window in wiring patterning of an integrated circuit board to miniaturize the wiring pattern width. and its manufacturing method.

(b) Background of the technology The general wiring material used in the circuit configuration of integrated circuit boards is aluminum (At) or an alloy of silicon (St) and aluminum, and aluminum films formed by sputtering etc. are used as resistors. The value is small.

Excellent adhesion and processability to silicon oxide films, etc. On the other hand, it has poor moisture resistance and migration (elect
Because it has a eutectic point with silicon, a eutectic alloy is formed at the contact surface where the aluminum film and the silicon/oxide film are in contact, causing deep pits in the silicon layer. On the other hand, wiring processing for aluminum or aluminum alloy films applied to the electrode windows in the source and drain regions involves placing a mask with a fine wiring pattern on the substrate and patterning it by exposing it to light, but this requires considerable precision in positioning. Since the electrode window in the above region may shift, it is necessary to take this amount of shift into account when designing the device.

(c) Prior art and problems Figures (a) and (b1) in Figures 1 and 2 are block diagrams showing a conventional example of an MO8 type semiconductor substrate, where (a) is a cross-sectional view and (b) is a cross-sectional view. FIG. 3 is a plan view showing a wiring pattern and electrodes.

The wiring pattern formed on the integrated circuit board is, for example, a MOS
In the device, source 2° and drain 3 diffusion is performed by ion implantation using an electrode 1 made of polycrystalline silicon (Poly-8T) as a diffusion mask, as shown in Figures 1 and 2. In the case of n-type, phosphorus (P) or arsenic (A8) is diffused to form an n region. Phosphorus silicate glass! 4 (PSG) to form an electrode window 5, and melt-processed. Electrode window 5 in source and drain 2 and 3 regions
An aluminum electrode 6 and a wiring pattern 7 are deposited on the substrate. The electrode window has a minute length of about 1μ, and the width of the wiring pattern 7 is also 1μ~
2μ, and strict precision is required for mask positioning during pattern transfer.The electrode 6 and wiring pattern 7 shown in Fig. 1 is ideal, but the pattern width becomes large and the degree of integration of the substrate is restricted. Moreover, as described above, mask alignment is difficult.

Therefore, by making the pattern width small and designing the device so that it can operate even if the overlapping with the electrode window 5 is slightly misaligned, the alignment accuracy of the strips will be reduced, but a part of the active region (source, drain) will be exposed. However, during etching during pattern formation, it is etched together with the aluminum film, resulting in deep bits 8, causing leakage at the junction with the n+ region and the p region, and damaging the substrate.

(d) Purpose of the Invention In view of the above points, the present invention has an object to provide a coating means for depositing and forming a conductive metal layer on an electrode window, thereby further reducing the width of a wiring pattern and increasing the integration of a semiconductor substrate. do.

(e) Structure of the Invention According to the present invention, in electrode patterning on a substrate, a window is formed in the insulating film on the substrate, and the first
After forming a conductive layer, a second conductive layer is formed on the first conductive layer, and the second conductive layer is patterned using the first conductive layer as a stopper. This is achieved by etching away the first quaternary layer using a mask.

(f) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a diagram showing a manufacturing process of a semiconductor device according to an embodiment of the present invention. (a) As shown in K, a conductive metal film is formed by sputtering on an integrated circuit substrate 11 on which source and drain regions have been formed by a diffusion process. The metal film 12 to be deposited has a film thickness of 500^ to 100A and is a material that is selective to aluminum etching, that is, a material such as tungsten (W) or molybdenum (Mo) that acts as a stopper during patterning of aluminum wiring and does not corrode the source and drain regions. Use. Next, as shown in (b), an aluminum layer is formed by sputtering, and aluminum electrodes 14 and a circuit pattern are formed by mask alignment. Next, the aluminum layer is etched, and the metal film 12 is further etched using the aluminum electrode 14 and aluminum wiring as a mask. When etching the aluminum layer, the periphery of the electrode window 13 is covered with a metal film 12 that is selective to aluminum etchant, so the n+ layer of the source or drain is not etched. Leak is prevented. Also, aluminum electrode 14
As is clear from the figure, a metal film 2 such as tungsten or molybdenum having a high melting point is interposed as a barrier material, so that eutectic formation with the silicon layer is prevented.

FIG. 4 is a sectional view showing a semiconductor substrate according to another embodiment of the present invention. In the figure, an electrode window 23 of an integrated circuit board 21
A conductive metal 22 is embedded by sputtering, and after etching, aluminum electrodes 24 and aluminum wiring are formed. In this case conductive metal 22
Since the film can be sufficiently thick, it may or may not be selective to aluminum etchant.

(g) Effects of the Invention As explained in detail above, in the semiconductor process of the present invention, by forming an integrated circuit in which conductive metal is deposited on the electrode window, there is no need to overlap the electrode window and the electrode. Furthermore, mask alignment accuracy during patterning is simplified, and high integration can be expected.

[Brief explanation of the drawing]

Figures 1 and 2 (a) and 2 (b) are diagrams showing the manufacturing process of a semiconductor device which is an embodiment of the MO8 type semiconductor based device, and Figure 4 is a diagram showing another embodiment of the present invention. FIG. 1 is a cross-sectional view showing a certain semiconductor substrate. In the figure, 11.21... integrated circuit board, 12.2
2... Metal film, 13.23... Electrode window, 14.24... Aluminum electrode. Mine 1 Close (”) '(-4
)≠? Sendai Ki・

Claims (2)

[Claims] (1) The electrode formed in the electrode window on the substrate is formed on a conductive layer of a different metal from the electrode, and is configured so that the electrode can be formed into a fine pattern similar to the electrode window. A semiconductor device characterized by: (2) In the electrode patterning performed on the substrate, a window is formed in the insulating film on the substrate, and after forming a first conductive layer by covering the window, a second conductive layer is formed on the first conductive layer. form a layer,
A semiconductor device characterized in that the second conductive layer is patterned using the first conductive layer as a stopper, and the first conductive layer is etched away using the second conductive layer as a mask. Production method.