Chemical vapor deposition process

Details Chemical vapor deposition process Chemical vapor deposition process

2002-01-15

2002-10-29

Ghyka, Alexander (Department: 2812)

Semiconductor device manufacturing: process

Coating with electrically or thermally conductive material

To form ohmic contact to semiconductive material

C438S683000, C438S685000, C438S792000

Reexamination Certificate

active

06472321

ABSTRACT:

BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to chemical vapor deposition processes related to the manufacture of integrated circuit devices. The present inventors have recognized a need for an improved chemical vapor deposition process for use in integrated circuit manufacture and, more particularly, a need for an improved process for forming an electrical contact to a semiconductor substrate.
In accordance with one embodiment of the present invention, a chemical vapor deposition process is provided. A semiconductor wafer is positioned in a reaction chamber. The semiconductor wafer includes an insulating layer disposed over a silicon substrate. The insulating layer defines a contact opening therein, the contact opening defining insulating side wall regions therein, the insulating side walls extending from an upper surface region of the insulating layer to an exposed silicon region of the silicon substrate. A set of reactants are introduced into the reaction chamber. RF plasma is generated in the vicinity of the semiconductor wafer and the temperature and pressure of the reaction chamber are regulated.
The introduction of the reactants, the generation of the RF plasma, and the regulation of the temperature and pressure are controlled so as to form a primary film over the upper surface region of the insulating layer, over the insulating side wall regions, and over the exposed silicon region of the silicon substrate. The primary film is formed over the upper surface region and the insulating side wall regions according to the following chemical reaction
TiCl
4
+H
2
Ti+
A
The primary film is formed over the exposed silicon region according to the following chemical reaction
TiCl
4
+H
2
+Si TiSi+
A
Si represents silicon present in the silicon substrate and A represents a non-film forming component of the chemical reactions. The primary film is characterized by a first thickness a over the upper surface region and a second thickness b over the exposed silicon region. The first thickness a is substantially less than the second thickness b.
The process may further comprise introducing a nitrogen-based gas into the reaction chamber and generating a nitridizing RF plasma in the vicinity of the semiconductor wafer so as to nitridize the primary film formed over the upper surface region, the insulating side wall regions, and the exposed silicon region. The nitridizing process causes conversion of the primary film formed over the upper surface region and the insulating side wall regions to a TiN layer and formation of a TiN passivation layer over the primary film formed over the exposed silicon region.
The first thickness a may comprise titanium and may be about ½ the magnitude of the second thickness b. The second thickness b of the primary film may comprise TiSi. The temperature of the reaction chamber may be regulated in the range of between about 500° C. and about 700° C. The pressure of the reaction chamber may be regulated in the range of between about 500 Pa and about 700 Pa. The set of reactants may be introduced into the reaction chamber with an inert gas, e.g., helium. The non-film forming component may include HCl, He, and combinations thereof.
The process may further comprise introducing a nitrogen-based gas into the reaction chamber and generating a nitridizing RF plasma in the vicinity of the semiconductor wafer so as to nitridize the primary film formed over the upper surface region, the insulating side wall regions, and the exposed silicon region. The nitridizing process may cause the primary film formed over the upper surface region and the insulating side wall regions to be converted to TiN and may cause the primary film formed over the exposed silicon region to be passivated with a layer of TiN. Prior to introducing the nitrogen-based gas into the reaction chamber, the reaction chamber may be purged of TiCl
4
.
The exposed silicon region of the silicon substrate typically comprises an active area of a semiconductor device and may, for example, be a diffusion region, a source region of a transistor, a drain region of a transistor, and a collector region of a transistor.
In accordance with another embodiment of the present invention, a chemical vapor deposition process is provided wherein a semiconductor wafer is positioned in a reaction chamber wherein the semiconductor wafer includes an insulating layer disposed over a semiconductor substrate, and the insulating layer defines a contact opening therein. The contact opening defines insulating side wall regions therein. The insulating side walls extend from an upper surface region of the insulating layer to an exposed semiconductor region of the semiconductor substrate. A set of reactants are introduced into the reaction chamber, RF plasma is generated in the vicinity of the semiconductor wafer, and the temperature and pressure of the reaction chamber is regulated.
The introduction of the reactants, the generation of the RF plasma, and the regulation of the temperature and pressure is controlled so as to form a primary film over the upper surface region of the insulating layer, over the insulating side wall regions, and over the exposed semiconductor region of the semiconductor substrate. A nitrogen-based gas is introduced into the reaction chamber and a nitridizing RF plasma is generated in the vicinity of the semiconductor wafer so as to nitridize the primary film formed over the upper surface region, the insulating side wall regions, and the exposed semiconductor region.
In accordance with yet another embodiment of the present invention, a chemical vapor deposition process is provided wherein a semiconductor wafer is positioned in a reaction chamber. The semiconductor wafer includes an insulating layer disposed over a silicon substrate and the insulating layer defines a contact opening therein. The contact opening defines insulating side wall regions therein, the insulating side walls extend from an upper surface region of the insulating layer to an exposed silicon region of the silicon substrate. A set of reactants are introduced into the reaction chamber, RF plasma is generated in the vicinity of the semiconductor wafer, and the temperature and pressure of the reaction chamber are regulated. The RF plasma is generated at a power of about 1000 W and the temperature of the reaction chamber is regulated in the range of between about 500° C. and about 700° C.
The introduction of the reactants, the generation of the RF plasma, and the regulation of the temperature and pressure is controlled so as to form a primary film over the upper surface region of the insulating layer, over the insulating side wall regions, and over the exposed silicon region of the silicon substrate. The primary film is formed over the upper surface region and the insulating side wall regions according to the following chemical reaction
TiCl
4
+H
2
Ti+
A
The primary film is formed over the exposed silicon region according to the following chemical reaction
TiCl
4
+H
2
+Si TiSi+
A
Si represents silicon present in the silicon substrate and A represents a non-film forming component of the chemical reactions, wherein the primary film is characterized by a first thickness a over the upper surface region and a second thickness b over the exposed silicon region, and wherein the first thickness a is substantially less than the second thickness b.
In accordance with yet another embodiment of the present invention, a chemical vapor deposition process is provided wherein a semiconductor wafer is positioned in a reaction chamber. The semiconductor wafer includes an insulating layer disposed over a silicon substrate and the insulating layer defines a contact opening therein. The contact opening defines insulating side wall regions therein, the insulating side walls extend from an upper surface region of the insulating layer to an exposed silicon region of the silicon substrate. A set of reactants are introduced into the reaction chamber, RF plasma is generated in the vicinity of t

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