JPH02159041A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent destructions of gate oxide films when ions are injected by removing the thickness of an insulating film on source and drain regions or causing the insulating film to be thinner than the thickness of a gate insulating film; besides, by thinly forming a conductor film on the whole face after forming the insulating film even on the gate insulating film. CONSTITUTION:After forming selectively a field oxide film 2 and a gate oxide film 3 on a substrate 1, a gate electrode material 4 is formed extensively. After forming a silicon dioxide film 5 which is thicker than the gate oxide film on a polycrystal silicon film 4, a prescribed gate electrode pattern 6 is formed on the polycrystal silicon film 4 as well as the silicon dioxide film 5 and a low concentrated impurity layer 7 is formed on the substrate. After forming the insulating film extensively, insulating films 8 are formed on sidewalls of the gate electrode pattern with an etchback process. In such a case, the polycrystal silicon film 4 and the gate oxide film which is exposed at a part other than the sidewall insulating films 8 are etched thinly or they are etched completely to expose a semiconductor substrate. Subsequently, after a conductor film 9 is formed extensively, highly concentrated impurities are injected in the substrate through ion implantation and then highly concentrated source and drain layers 10 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a high performance semiconductor device.

2. Description of the Related Art In the conventional method for forming sources and drains of MO3 type semiconductor devices, as shown in FIG. 3, a field oxide film 22 . After forming a gate insulating film 23 and a gate electrode pattern 24 such as a polycrystalline silicon film, a low concentration impurity diffusion layer is formed (FIG. 2(A)), and then an insulating film 25 is formed on the sidewalls of the polycrystalline silicon film pattern. , and using the sidewall insulating film as a mask, a highly concentrated impurity layer 26 was formed on the semiconductor substrate by ion implantation to serve as a source/drain (FIG. 3(B)).

Problems to be Solved by the Invention The conventional method described above has the problem that charge is accumulated in the gate electrode pattern during high-concentration ion implantation, and a high voltage is applied between the gate electrode pattern and the substrate, destroying the gate insulating film. Ta.

Means for Solving the Problems In order to solve the above problems, the present invention removes the thickness of the insulating film on the source/drain or makes it thinner than the gate insulating film, and also forms an insulating film on the gate insulating film. After the formation, a thin conductive film is formed over the entire surface, and a highly concentrated impurity layer is formed by ion implantation to form source/drain layers.

Effect: According to the method of the present invention, all of the charges in the conductor film generated during the formation of the highly concentrated impurity layer are leaked to the substrate directly to the source/drain region or via a thin insulating film on the source/drain region. Therefore, a high-performance MO8 type field effect semiconductor device can be manufactured without destroying the gate insulating film as in the conventional example.

Example An embodiment of the present invention will be described with reference to FIG.

- After selectively forming a field oxide film 2 and a gate oxide film 3 on a conductive semiconductor substrate 1, a gate electrode material 4, such as an impurity-containing polycrystalline silicon film, is formed on the entire surface.

Next, after forming a dioxide/silicon oxide film 5 thicker than the gate oxide film on the polycrystalline silicon film 4 (see FIG. A gate electrode pattern 6 is formed, and a low concentration impurity layer 7 is formed on the semiconductor substrate (FIG. 3(B)). After forming an insulating film over the entire surface, the insulating film 8 is formed on the side walls of the gate electrode pattern by an etch-back method. At this time, the etch-back time is longer than the etching time for the film thickness of the insulating film 8 (etching,
The gate oxide film exposed except for the polycrystalline silicon film 4 and the sidewall insulating film 8 is thinly etched (FIG. (C)). Alternatively, the entire gate oxide film is etched to expose the semiconductor substrate. Next, a conductor is deposited on the entire surface. membrane 9
For example, after forming an impurity-containing polycrystalline silicon film, high concentration impurities are ion-implanted into the semiconductor substrate to form a high concentration source/drain layer 10 (FIG. 3(D)). Next, after completely removing the conductive film 9, an interlayer film 11 and a metal wiring layer 12 are formed to form a semiconductor device (see FIG.
).

In the above embodiment, after forming an insulating film on the sidewalls of the gate electrode (FIG. 1(C)) and removing all the gate oxide film 13 on the source/drain, a conductive film 9 is formed to form a high-concentration film. A source/drain layer may also be formed. At this time,
As shown in FIG. 2, the conductor 1 may be selectively left without being completely removed and used as the lead wiring 14 from the source/drain.

Effects of the Invention According to the method of the present invention, a conductive film is formed on the entire surface when forming a high concentration impurity layer in the source/drain, and the conductive film is formed on the entire surface of the semiconductor in the source/drain region through an oxide film thinner than the gate oxide film or directly. Because it is in contact with the substrate, all the charges induced on the surface during ion implantation flow to the source/drain region, preventing the gate oxide film from being destroyed (which makes it possible to form a semiconductor device with good characteristics). .

[Brief explanation of the drawing]

FIG. 1 is a process sectional view for explaining one embodiment of the present invention, and FIG. 2 is a film for explaining another embodiment of the present invention. Name of agent: Patent attorney Shigetaka Awano Haka 1 person 1...
...Semiconductor substrate, 3...Gate insulating film, 4...
...Gate electrode, 5, 8... Insulating film, 9.
・・・Conductor diagram

Claims (2)

[Claims] (1) In the manufacturing process of a MOS type field effect semiconductor device, there is a step of forming a conductive film on the entire surface of the semiconductor substrate through an insulating film thinner than the gate insulating film, and an ion implantation method into the semiconductor substrate from above the conductive film. A method of manufacturing a semiconductor device, comprising the steps of forming a source/drain by implanting impurities, and removing the conductor film. (2) In the manufacturing process of a MOS field effect semiconductor device, a process of forming a conductor film in contact with the semiconductor substrate through the gate electrode and the insulating film and in areas other than the gate region, and an ion implantation method into the semiconductor substrate through the conductor film. A method for manufacturing a semiconductor device, comprising the step of introducing an impurity.