JPH03248420A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable diffusion of impurities to be controlled for improving the amount of activation and uniformity of implantation distribution of the impurities to be improved by performing a high-speed annealing treatment simultaneously or continuously when introducing the impurities using plasma. CONSTITUTION:An anode 4 is provided within a reactor 3, a plasma is generated by applying voltage to a susceptor 5 which is a cathode electrode, ions are accelerated in the direction of electric field, and impurities are introduced into a semiconductor substrate 1. A crystal plate 6 is mounted to a side wall of the reactor 3 and a lamp 2 such as a tungsten halogen lamp and a reflection plate 7 are mounted to an outside of the crystal plate 6 TO enable RTA treatment to be made. When impurities are introduced into the semiconductor substrate 1 by plasma doping, the semiconductor substrate 1 is rapidly heated by the lamp 2 such as the tungsten halogen lamp simultaneously to activate the introduced impurities or the impurities are introduced into the conductor substrate 1 after plasma doping and are rapidly heated by the lamp 2 continuously to activate the impurities.

Description

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 manufacturing a semiconductor device suitable for forming a shallow junction.

[Conventional technology]

In the semiconductor manufacturing process represented by @LsI, it is necessary to introduce impurities many times. Impurities can be introduced by thermal diffusion from gaseous or solid impurity sources or doped glass deposited directly on the surface.

There are ion implantation methods, etc. In the latest LSIs, the degree of integration is increasing, and transistors are becoming smaller. As a result, process techniques such as forming shallow junctions and doping the vertical sidewalls of high aspect ratio trenches are required to suppress short channel effects. The principle of ion implantation, which is one of the conventional methods, is well understood, but it is difficult to generate a large current at a low acceleration voltage, and heat treatment is required after implantation to recover crystal defects caused by implantation. Therefore, it is difficult to form a shallow junction of about 0.1 .mu.m, and doping the sidewalls of the trench causes problems such as the generation of undoped regions due to shadowing effects.

One method of introducing impurities to solve these problems
One example is plasma doping. This method dilutes a doping gas such as BZ HA, A S H3, PH:+ with a gas such as H, He, Ar, etc., generates plasma, and introduces impurities into the semiconductor substrate by an electric field between the semiconductor substrate and an electrode. This is the way to do it. Using this method, it is possible to introduce impurities into the interior of a trench with a high aspect ratio, it is possible to form a shallow junction with a high concentration, and damage to the semiconductor substrate is reduced.

Fig. 3 shows a conventional plasma doping apparatus, in which doping gas is sealed into a reactor 3 through a gas introduction pipe 8, and a discharge is caused between an anode 4 and a cathode electrode, which is a susceptor 5, to generate plasma. By doing so, impurities are introduced into the semiconductor substrate 1.

[Problem to be solved by the invention]

In conventional plasma doping, the vicinity of the surface of a semiconductor substrate is doped with impurity atoms of 10 "atoms/cm" or more, but there is a problem that the activation concentration is low. For example, the impurity atom is 1.0"
Even though it is doped with atoms/cm' or more, the activation amount is about 10''/cm'.

As a result, heat treatment after plasma doping has become indispensable, and it has become difficult to form shallow junctions due to the spread of carriers due to thermal diffusion.

Furthermore, since impurities introduced into a semiconductor substrate by plasma doping are accelerated at low energies of several hundred eV to several KeV, they are extremely sensitive to the condition of the implanted surface, causing non-uniformity in the impurity implantation distribution. There was also the problem that it was difficult to control the impurity concentration.

This invention was made to solve the above-mentioned problems, and it is possible to improve the activation amount without significantly diffusing impurities introduced by plasma doping, and to improve the uniformity of the impurity implantation distribution. The purpose of this invention is to obtain a method for manufacturing a semiconductor device.

[Means to solve the problem]

In the method for manufacturing a semiconductor device according to the present invention, when impurity atoms are introduced into a substrate by a plasma doping method, rapid thermal annealing (RT) is performed at the same time or in succession.
A; Rapid Thermal Anneal
) processing.

[Effect]

When an impurity layer is formed by the method of manufacturing a semiconductor device according to the present invention, since PTA treatment is performed simultaneously with plasma doping or consecutively, the spread of impurities is suppressed, the amount of activation can be increased, and a shallow junction can be formed. . Furthermore, the amount of doping can be increased by promoting the reaction on the substrate surface, and the amount of activation in the substrate can be controlled by controlling the PTA treatment temperature.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a method of manufacturing a semiconductor device according to an embodiment of the present invention, in which 1 is a semiconductor substrate, 2 is a lamp, and 7 is a reflector.

As shown in the figure, when impurities are introduced into the semiconductor substrate 1 by plasma doping, the semiconductor substrate 1 is simultaneously rapidly heated with a lamp 2 such as a tungsten halogen lamp.
Activate the introduced impurities. Alternatively, impurities are introduced into the semiconductor substrate 1 by plasma doping and then rapidly heated by the lamp 22 to activate the impurities.

Further, FIG. 2 shows an example of a semiconductor manufacturing apparatus for realizing the semiconductor device manufacturing method of the present invention, in which the same reference numerals as in FIG. 1 indicate the same parts, 3 is a reactor, 4 is an anode electrode, and 5 is an A susceptor is a cathode electrode, 6 is a quartz plate, 8 is a gas introduction pipe, 9 is an exhaust pipe, 10 is an exhaust pump, and 11 is an insulator.

As shown in the figure, an anode 4 is provided within the reactor 3,
By applying a voltage to the susceptor 5, which is a cathode electrode, plasma is generated, ions are accelerated in the direction of the electric field, and impurities are introduced into the semiconductor substrate 1. A quartz plate 6 is attached to the side wall of the reactor 1, and a lamp 2 such as a tungsten halogen lamp and a reflector 7 are attached to the outside of the quartz plate 6, so that PTA processing can be performed. The doping gas is introduced into the reactor 3 through the gas inlet 8 and exhausted by the pump 10 through the exhaust port 9. Further, the susceptor 5, which is a cathode electrode, is insulated from the reactor 3 by an insulator 11.

Hereinafter, the characteristics of the method for manufacturing a semiconductor device according to the present invention will be explained. In the present invention, R
Since the TA treatment is performed, the amount of activation of the introduced impurities is increased, and because of the rapid heating and short time treatment, the diffusion of the introduced impurities can be suppressed, and as a result, it is possible to form shallow junctions. Become. Furthermore, since the semiconductor substrate is irradiated with light from a lamp during plasma doping, substrate surface reactions are promoted, and as a result, the amount of introduced impurities increases. Furthermore, the amount of activated impurities introduced can be controlled by changing the temperature of the RTA treatment. In addition, PTA is applied continuously to plasma doping.
When processing is performed, rapid heating and short-time processing is performed, making it possible to form a shallow bond.

In addition, in the above embodiment, the PTA treatment was performed simultaneously with plasma doping or sequentially, but as a further example of the above embodiment, as shown below, the PTA treatment was performed by changing the atmosphere for each treatment. You may go. -To give an example, first of all, NF3, Cj! A strongly reducing gas such as z gas is sealed in the reactor 3, and rapid heating is performed by PTA treatment. As a result, the native oxide film formed on the substrate is removed, and the surface into which impurities are introduced is cleaned. Next, the gas in the reactor is exhausted, and then Bz Hb, AsH3, PH
A doping gas such as No. 3 is sealed in a reactor to generate plasma, and RTA treatment is performed at the same time or in succession. In this embodiment, which performs this series of processing, in addition to the above embodiment, the native oxide film can be removed before plasma doping, and the substrate surface can be cleaned, so that the uniformity of impurity distribution can be further improved. .

〔Effect of the invention〕

As described above, according to the present invention, since the PTA treatment is performed simultaneously with plasma doping or consecutively, it is possible to introduce high concentration impurities into the semiconductor substrate.
In addition, a shallow junction can be formed, and a semiconductor device with high precision that is resistant to short channel effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the method for manufacturing a semiconductor device of the present invention;
FIG. 2 is a diagram showing a semiconductor manufacturing apparatus for implementing the semiconductor device manufacturing method of the present invention, and FIG. 3 is a diagram showing a conventional semiconductor manufacturing apparatus. 1 is a semiconductor substrate, 2 is a lamp, 3 is a reactor, 4 is an anode electrode, 5 is a susceptor which is a cathode electrode, 6 is a quartz plate, 7 is a reflection plate, 8 is a gas introduction pipe, 9 is an exhaust pipe, 10 is an exhaust gas The pump 11 is an insulator. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A method for manufacturing a semiconductor device, characterized in that a high-speed annealing process is performed simultaneously or consecutively when introducing impurities using plasma.