JPH03153045A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To eliminate an irregularity in sidewalls of a gate electrode and to realize a uniform transistor characteristic over a wafer by a method wherein an ozone- and organic silicon-based silicon oxide film is used to form the sidewalls of the gate electrode. CONSTITUTION:A well 12 and a LOCOS 13 are formed on a semiconductor substrate 11; after that, a gate insulating film 14 is formed in a high-temperature oxidizing atmosphere; in succession, polycrystalline silicon is vapor-grown. Then, a patterning operation is executed by a dry etching operation by making use of the polycrystalline silicon as a mask; a gate electrode 15 is formed. In succession, low-concentration ions are implanted by making use of a photoresist as a mask. In order to form a silicon oxide film for sidewalls, organic silane and oxygen gas containing ozone are introduced into a reaction container and are vapor-grown by a bubbling operation using an inert gas as a carrier gas. After that, an anisotropic dry etching operation is executed by using an etching gas; the silicon oxide film is left selectively on side faces of the gate electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing semiconductor devices, particularly MO5I transistors.

[Prior Art] Conventionally, a method for manufacturing a miniaturized semiconductor device is L D
Taking a D (Lightly Doped Drain) structure MOS transistor as an example, as shown in FIG. 2, a gate insulator Il! After forming 24 in a high-temperature oxidizing atmosphere, a polycrystalline silicon film is grown in a vapor phase to a thickness of about 0.4 μm, and this is patterned by dry etching using a photoresist mask to form a gate electrode 25. Next, after implanting low concentration impurities using a photoresist as a mask, a silicon oxide film of about 0.5 μm is deposited on the entire surface of the substrate by vapor phase growth using monosilane as a raw material, and anisotropic dry etching is performed perpendicular to the substrate. As a result, the silicon oxide film is selectively left on the side surfaces of the gate electrode to form sidewalls 26. Thereafter, source/drain regions are formed by implanting high-concentration ions, and a second field insulating film 27 is formed by vapor phase growth. Contact holes are then opened using a photoresist as a mask, and aluminum alloy is deposited in a 0.0-. 5-1
．． After 0 μm sputtering, patterning is performed by dry etching using a photoresist as a mask to form wiring.

[Problem to be Solved by the Invention 1] However, in the prior art, as shown in FIG. 3, the coverage of the side wall portion of the CVD silicon oxide film 36 made from monosilane is about 60% of the top of the step. The silicon oxide film required for sidewall formation must be made thicker. The thicker the silicon oxide film on the gate electrode or active region, the longer the etch-packing time will be. This causes a large variation in the results.

The sidewalls in an LDD structure have a large effect on the characteristics of the transistor; for example, if the width of the sidewalls is too narrow, it becomes vulnerable to hot electrons.

In addition, because the coverage of the CVD silicon oxide film varies within the wafer, it is partially overetched, creating a step between the gate electrode and the sidewall, which does not disappear even with the subsequent deposition of the CVD silicon oxide film in the second field. This may cause the aluminum wiring that crosses over the wire to break.

However, the present invention is intended to solve such problems, and its purpose is to eliminate variations in the sidewalls of the gate electrode sidewalls, realize uniform transistor characteristics within the wafer, and achieve high yield and reliability. Our goal is to provide high quality semiconductor devices.

[Means for Solving the Problems 1] The method for manufacturing a semiconductor device of the present invention provides a semiconductor device having a sidewall on the side wall of a gate electrode of a MOS transistor, in which the sidewall is placed in an oxygen atmosphere containing organic silane and ozone. It is characterized by being formed from a reacted silicon oxide film.

[Example 1] Hereinafter, steps in an example of the present invention will be explained in detail based on FIG. 1.

First, as shown in FIG. 8, a WELL 12.
After forming the LOCO 513, a gate insulator 11114 is formed in a high-temperature oxidizing atmosphere, and then polycrystalline silicon is grown in a vapor phase to a thickness of about 0.4 μm. Buttering is performed by dry etching to form the gate electrode 15.
form. Next, low-concentration ions are implanted using the photoresist as a mask to form the silicon oxide film of the sidewall 16. TEOS ([Si (
Organic silane such as QC28s)4]) and ozone at about 5%
Containing oxygen gas at approximately 100 Torr and substrate temperature at 350 Torr.
It was introduced into a reactor kept at ℃ and grown to about 0.4 μm in vapor phase. Thereafter, by performing anisotropic dry etching using an etching gas such as CF410, a silicon oxide film is selectively left on the side surfaces of the gate electrode.

Subsequently, source/drain regions are formed by high-degree ion implantation. After that, as shown in Fig. C, a second field insulating film 17 is formed by vapor phase growth, and a contact hole is opened using a photoresist as a mask. As a mask, C12 and Bcts
Dry etched and buttered with halogen gas such as Let's say Ji18.

In the semiconductor device made in this way, the coverage of the ozone-organosilicon based silicon oxide film on the stepped side surface is 100%.
Compared to monosilane-based silicon oxide films, the film thickness required to form sidewalls can be reduced by 20 to 50%, and the time to etch this silicon oxide film can be shortened. It is possible to reduce the variation in the width of the .

[Effect of the invention 1 As described above] According to the present invention, by using an ozone-organosilicon-based silicon oxide film to form the sidewall of the gate electrode, variations in transistor characteristics can be reduced and the yield is high. Moreover, a highly reliable semiconductor device can be provided.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(c) are cross-sectional views showing an embodiment of the method for manufacturing a semiconductor device of the present invention. FIG. 2 is a cross-sectional view showing a conventional semiconductor manufacturing method. FIG. 3 is a cross-sectional view showing the step coverage of a silane-based silicon oxide film. 11, 2 l, 3 l ・ l 2, 22, 32 13, 23, 33 ・ 14, 24, 34 ・ l 5, 25, 35 ・ l 6, 26 ・ ・ ・ ・ 17, 27 ・ ・ ・ ・ 18, 28 ・ ・ ・ ・ ・ l 9, 29 ・ ・ ・ ・ ・ l Ol 20 ・ ・ ・ ・ 36 ・ ・ ・ ・ ・ ・ ・ Semiconductor substrate/Well ・LOGOS Gate oxide film/Gate electrode/Side wall/Second field/Aluminum wiring・Low concentration ion implantation region ・High concentration ion implantation region ・Silane-based CVD flit silicon film

Claims (1)

[Claims] In a semiconductor device having a spacer (hereinafter referred to as a sidewall) made of an insulating film on the sidewall of a gate electrode of a MOS transistor, the sidewall is formed of a silicon oxide film reacted in an oxygen atmosphere containing organic silane and ozone. A method of manufacturing a semiconductor device, characterized in that: