JPS63157443A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To constitute a two-layer structure of a silicon oxide film layer and an organic silicon thin film layer, and obtain a semiconductor element with highly insulative property by a simple process, by a method wherein a substrate is exposed in oxygen plasma, and the organic functional group of an organic silicon thin film is removed, after a liquid containing organic silicon is spread on a semiconductor substrate having unevenness on the surface and a heat treatment is performed. CONSTITUTION:After a field oxide film 2 is formed on a semiconductor substrate 1, a gate oxide film 3 and a polysilicon gate 4 are formed in order, and a diffusion layer 5 is formed in a source.drain region by an ion implantation method. After a first interlayer insulating film 6 is formed, contact holes 7 are formed by anisotropic etching. On the holes 7, an aluminum wiring with specified thickness is formed, and thereon, a second interlayer insulating film 9 with specified thickness is formed. A liquid containing organic silicon is spread, which is made an organic silicon thin film 10 by thermal treatment. Then the substrate 1 is exposed to oxygen plasma, and a two-layer structure of the thin film 10 and a silicon oxide film 11 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a semiconductor device having a highly reliable multilayer wiring structure.

In conventional semiconductor devices, in order to obtain a highly reliable multilayer wiring structure, it is necessary to planarize the interlayer film between metal wiring layers. Conventionally, an etch-back method or a lift-off method has been used for this planarization. These methods are based on the premise that the interlayer film completely fills the gaps between metal wirings. However, in recent years, as semiconductor devices have become more highly integrated, the gaps between metal interconnects have become narrower, making it difficult to fill the gaps with insulating films. Therefore, flattening is difficult with the above method. In recent years, a bias sputtering method has been developed that can fill insulating films even into narrow gaps between metal wiring lines, but the bias sputtering method has the drawback of damaging elements formed on a substrate. Therefore, a method called the spin-on glass method is currently attracting attention. This involves applying an inorganic or organic silicon-containing liquid onto a substrate and applying heat treatment to form an inorganic or organic silicon thin film.In order to form an insulating film by applying the liquid, it also fills the narrow gaps between metal wiring. This makes it possible to flatten the surface. However, the IJ formed by the spin-on glass method
The 1N oxide film has the drawback of being prone to cracking and peeling, and the organic silicon thin film formed by the spin-on glass method has the drawback of not being susceptible to cracking and peeling, but does not have sufficient insulating properties.

Problems to be Solved by the Invention In order to obtain a semiconductor device having a highly reliable multilayer wiring structure, it is necessary to flatten the interlayer film between wiring metal layers. However, as mentioned above, as elements become increasingly miniaturized, conventional planarization methods are reaching their limits. Therefore, in view of the various drawbacks of the conventional methods, the present inventors focused on the spin-on glass method, which can be used even if elements become further miniaturized in the future. As a result of devising and researching various methods that combine the advantages of both organic silicon thin films and have high insulating properties without causing cracks or peeling, the present invention is a means for solving problem 1. After applying a silicon-containing liquid and applying heat treatment, the substrate is exposed to oxygen plasma to remove the organic functional groups on the surface of the organic silicon thin film, changing it to a two-layer structure of a silicon oxide film layer and an organic silicon thin film layer.

After forming a functional organic silicon thin film, if it is exposed to oxygen plasma to form a two-layer structure of a silicon oxide film layer and an organic silicon thin film layer, cranking and peeling are less likely to occur because of the presence of the organic silicon thin film layer below. Furthermore, since the silicon oxide film is in contact with the upper metal wiring, it has sufficient insulation properties. In this way, a semiconductor device having a highly reliable multilayer wiring structure can be obtained.

EXAMPLES The present invention will be explained in more detail below based on the drawings.

1 to 4 are partially enlarged cross-sectional views showing steps of an embodiment of the method for manufacturing a semiconductor device according to the present invention.

In FIG. 1, after a field oxide film 2 is formed on a semiconductor substrate 1 using a selective oxidation method, a gate branching film 3 and a poly 7 recon gate 4 are formed in this order, and then diffused into the source and drain regions using an ion implantation method. Layer 5 is provided. Next, the first interlayer insulating film 6 made of borophosphorus glass or the like is entirely formed, and a contact hole 7 is formed by anisotropic etching. A first aluminum wiring 8 having a thickness of 1 μm is formed thereon, and a second interlayer insulating film 9 is formed by about 500 times. As the second interlayer insulating film 9, a silicon oxide film formed by a plasma CVD method or the like is suitable. Next, approximately 3,000 people applied a liquid containing organic silicon. As an organic silicon-containing liquid, (C6H5)n
A solution containing a compound having the structure S1(OH)4-n is used. Since the organic silicon-containing liquid enters even the narrow grooves, it is possible to almost eliminate the unevenness on the substrate that existed before application. Next, the semiconductor substrate 1 is subjected to a heat treatment (the temperature is increased in several steps from room temperature, and the final temperature is 460° C. for 30 minutes) to form an organic silicon thin film 10 (FIG. 2). When the semiconductor substrate 1 is then exposed to oxygen plasma for 10 minutes, the organic functional groups of the organic silicon thin film 10 are detached to a predetermined depth.
Changes to silicon oxide film. Therefore, most of the thinner parts of the initially formed organic silicon thin film 10 change to the silicon oxide film 11, and only the thicker parts become a two-layer structure of the silicon oxide film 11 and the organic silicon thin film 1o (see Figure 3).

A through hole 12 between wiring layers is provided on the substrate, and a second aluminum wiring 13 is formed (FIG. 4). Organic silicon-containing liquid on the substrate? Since it is coated and flattened, the second aluminum wiring 13 is prone to disconnections and short circuits. Moreover, since the silicon oxide film 11 is in direct contact with the second aluminum wiring 13, it has sufficient insulation properties. Also, the first
The thick part of the interlayer film between the aluminum wiring a8 and the second aluminum wiring 13 has a two-layer structure of a silicon oxide film and an organic silicon thin film, and cracks are difficult to occur because there is an organic silicon thin film layer underneath.

The organosilicon containing ii used in the manufacturing method according to the present invention is R
It is desirable to include a compound having the structure n5i(OH)4-n(R, alkyl group) or 5i(OR)4(R: alkyl group), and among them, the compound used in this example (C
A bath solution containing 6H5)nSi(OH)4-n' exhibits extremely excellent properties.

Effects of the Invention By using the manufacturing method according to the present invention, it is possible to flatten the interlayer film between wiring metal layers through a simple process. Furthermore, since the silicon oxide film and the organic silicon thin film are all combined, it is possible to obtain a highly reliable semiconductor device with high insulation properties and no cracking or peeling noise.

Since the manufacturing method according to the present invention performs flattening by applying a liquid, it can cope with even further progress in element miniaturization in the future. There is no other manufacturing method like this, and it is of extremely high industrial value.

[Brief explanation of the drawing]

1 to 4 show the steps of an embodiment of manufacturing a semiconductor device according to the present invention, FIG. 1 is a partially enlarged sectional view of a semiconductor substrate used in the manufacturing method according to the present invention, and FIG. FIG. 3 is a partial enlarged cross-sectional view of the semiconductor substrate after the organic silicon thin film has been formed. FIG. 3 is a partial enlarged cross-sectional view of the semiconductor substrate after the semiconductor substrate has been exposed to oxygen plasma. FIG. This is a partially enlarged sectional view of the semiconductor substrate after the second aluminum wiring is completely formed. 1...Semiconductor substrate, 2...Field oxide film, 3...Gate oxide film, 4...
Polysilicon gate, 6...diffusion layer, 6...
...First interlayer insulating film, 7...Contact hole, 8°° first aluminum wiring, 9...Second interlayer insulating film, 1o...Organic silicon Thin film, 11...
...Silicon i version J11! , 12...Through hole, 13...Second aluminum wiring. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4, Borisisokonge) Qv-Koshika Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] a step of forming an organic silicon thin film on a semiconductor substrate;
A method for manufacturing a semiconductor device, comprising forming a two-layer structure of a silicon oxide film layer and an organic silicon thin film layer on a semiconductor substrate by a step of removing organic functional groups of the organic silicon thin film from the surface to a predetermined depth.