JPS62291146A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent aluminum wirings from being disconnected even in a fine hole by coating it with aluminum and heat treating it at 600 deg.C or higher. CONSTITUTION:After a thermal oxide film 2 is formed on a silicon substrate 1 and a polycrystalline silicon gate electrode 3 is formed, a source region 4a and a drain region 4b are formed, a silicon oxide film 5 is formed by a vapor growth method, and a hole 6 is opened. Then, a titanium nitride film 7 is deposited by a sputtering method, and an aluminum 8 is further deposited. The aluminum 8 immediately after depositing is thinner than a flat part in the hole 6 of the silicon oxide film. When it is heat treated at 700 deg.C for 5 sec in an N2 atmosphere by a lamp annealing, the aluminum reflows even in a fine hole under its surface tension to improve the shape of the aluminum 8 in the hole 6. Thereafter, the aluminum 8 is selectively etched by a photoetching technique to form aluminum wirings 8a.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming aluminum wiring.

[Conventional technology]

Conventionally, aluminum wiring has been formed on an insulating film having openings by, for example, the method shown in FIGS. 2(a) and 2(b). In other words, first of all, Figure 2 (
As shown in a), an impurity diffusion layer 1 is formed on a silicon substrate 11.
2 is formed, the surface of the silicon substrate is covered with a silicon oxide film 13, and openings 14 are provided at predetermined positions of the silicon oxide film 13. Next, as shown in FIG. 2 (bl), aluminum 9 is deposited by sputtering on the silicon oxide gland 13 including the opening 14, and the aluminum 9 is selectively etched by photolithography. m completely formed.

[Problem that the invention seeks to solve]

In the conventional aluminum wiring forming method described above, the thickness of the aluminum 15 becomes thinner at the opening 14 provided in the silicon oxide film 13, as shown in FIG. As miniaturization progresses, this becomes more noticeable, and disconnections at the openings 14 of the aluminum wiring 15 are likely to occur, which is unfavorable in terms of reliability.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes: forming a hole in the insulating film of a semiconductor substrate torn by the insulating film; The step of forming the aluminum coating includes heat treating the aluminum at 660° C. or higher.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 (al to (dl) are cross-sectional views in the order of steps of an embodiment in which the present invention is applied to an MO8 type semiconductor device.
As shown in FIG. A silicon oxide film 5 is formed by a vapor phase growth method, and an opening 6 is made in the silicon oxide film 5.

Next, as shown in FIG. 1tbl, a titanium nitride film 7 was deposited to a thickness of 05 μm by sputtering, and then aluminum 8 was deposited to a thickness of 1 μm by sputtering. Here, the empty titanium film 7 is deposited as a barrier metal to prevent aluminum from diffusing into the silicon substrate during the heat treatment process. Immediately after deposition, the thickness of the aluminum 8 becomes thinner in the opening 6 of the silicon oxide film than in the flat part. The finer the apertures 6, the more noticeable the nicks become. Next, N was applied using the lamp annealing method.

A heat treatment is performed in an atmosphere at a temperature of 700° C. for 5 seconds to obtain the state shown in FIG. 1 [C]. The melting point of aluminum is 6
60°C, so at a temperature of 700°C, aluminum has an IJ 70-
However, the shape of the aluminum 8 in the opening 6 is improved. The barrier resistance of titanium nitride against diffusion of silicon and aluminum usually disappears if heat treatment is performed for a long time, for example, 30 minutes at 700"C, but if titanium nitride 7 is formed with sufficient care, Even at °C, if heat treatment is performed for a short time, for example, 5 seconds, the barrier resistance will not be lost.

Next, as shown in FIG. 1(d), the aluminum wiring 8 is selectively etched by photolithography.
A was formed to fabricate an MO8 type transistor.

In this embodiment, a lamp annealing method was adopted to perform the aluminum glue flow, but if a barrier metal having higher heat resistance than titanium nitride is used, heat treatment using a normal furnace may be performed.

〔Effect of the invention〕

As explained above, according to the present invention, by performing heat treatment at 660'C or more and reflowing the aluminum in the opening of the insulating film, the shape of the aluminum inside the opening is completely changed.
Breaking of the aluminum wiring can be prevented even in the minute openings, which has the effect of significantly improving the reliability of the semiconductor device.

[Brief explanation of the drawing]

FIGS. 1(a) to (d) are cross-sectional views in the order of steps for explaining an embodiment of the present invention, and FIGS. 1.11...Silicon substrate, 2...Silicon thermal oxide film, 3...Polycrystalline silicon gate electrode, 4a, 4b.
- Source/drain region, 5...Silicon oxide film, 6
...Opening in insulating film, 7...Titanium nitride film, 8,9...
・Chrysanthemum/mouth

Claims (1)

[Claims] A step of forming a hole in the insulating film on a semiconductor substrate covered with an insulating film, a step of forming a barrier metal layer and an aluminum layer on the insulating film including the hole, and a heat treatment of the aluminum at 660° C. or higher. A method for manufacturing a semiconductor device, comprising the step of: