JPH03248419A - Semiconductor production device - Google Patents

Abstract

PURPOSE:To eliminate non-uniformity of implantation distribution and enable the amount of implantation to be increased by applying light or laser light onto a semiconductor substrate surface, a plasma region, or a partial region along with occurrence of plasma in an impurity implantation process. CONSTITUTION:An ArF laser light 14 is applied onto an entire region within a plasma, one part within plasma, a surface of a wafer 4, or a part of the wafer where an impurity is be implanted. When laser is irradiated into plasma, the energy enables a molecule within plasma which is not ionized to be decomposed, amount of existing ions such as plasma AS<+> and B<+> to be increased, the number of implanted ions per unit area to be increased, and a density 13 of the implanted ion seed to be increased. When laser light is applied onto a surface of the wafer, excitation energy by laser light enables activation rate to be increased, thus promoting substrate surface reaction. Therefore, process time is reduced, inferior influence of a natural oxide film 12 which exists on the surface of the wafer can be prevented, and non-uniformity of an implanted distribution 11 and the amount of implantation can be fully avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor manufacturing apparatus, and particularly to a semiconductor manufacturing apparatus that forms an impurity layer.

[Conventional technology]

In manufacturing a semiconductor device, there are many steps for forming an impurity layer. Methods for forming the impurity layer include ion implantation, doping gas, and thermal diffusion using doped glass. By the way, with the remarkable development of LSI in recent years, the degree of integration has increased and the area of the transistors that make up the LSI has been reduced, and the short channel effect, which is one of the problems that occur in such transistors, has been reduced. Formation of shallow junctions is one of the important processes to suppress this. The principle of the conventional ion implantation method is well understood, but a certain amount of heat treatment is required to recover crystal defects that occur during implantation, and as a result of the heat treatment, the junction depth can be reduced. This meant that some problems remained. Furthermore, when doping the sidewalls of the trench structure, restrictions are placed on the implantation angle, resulting in the problem that the desired implantation distribution and amount cannot be obtained.

Here, one of the impurity doping methods that is attracting attention in such an environment is a plasma doping method. In this method, a doping gas such as B2H4 or ASH3 is turned into plasma, and the semiconductor substrate is doped by an electric field existing between the semiconductor substrate and an electrode. FIG. 2 is a cross-sectional side view showing such a plasma doping apparatus, and in the figure, 1 is a plasma reaction vessel, 2 is an upper electrode, 3 is a lower electrode, 4 is a wafer,
6 is a gas inlet, 7 is a gas exhaust port, 8 is a matching box, and 9 is an RFt source. As shown in the figure, first, the gas introduced from the gas inlet 6 is ASH:l, B2H2 diluted with an inert gas such as He. Next, plasma is generated between the upper and lower electrodes. At this time, As”, B
Ions such as + are accelerated to several hundred to several KeV and implanted into the wafer 4. By using such plasma, it is possible to uniformly dope impurities inside a trench with a high aspect ratio, and since the surface of the semiconductor substrate is irradiated with low energy of several hundred eV, it is possible to form shallow junctions, and it is also possible to form shallow junctions in the semiconductor substrate. Damage to the surface is also suppressed.

[Problem to be solved by the invention]

By the way, although the conventional plasma doping method is an effective process as described above, there are some problems.

One of them is the influence of a natural oxide film existing on the surface of the semiconductor substrate. FIG. 3 shows the distribution of implanted ions in the substrate during plasma doping using the conventional plasma doping apparatus shown in FIG. A natural oxide film formed on the surface, 13, indicates the density of the implanted ion species.

The ion species implanted by such a plasma doping method have a low energy of several hundred eV, so they are very sensitive to the condition of the implanted surface, and the natural oxide film 12 existing on the substrate surface is affected. The oxide film 12 acts as a mask for the implanted ions, resulting in non-uniformity in the implanted impurity distribution and a reduction in the implanted amount.

This invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a semiconductor manufacturing apparatus that can eliminate non-uniformity of implantation distribution in plasma doping and increase the amount of implantation. With the goal.

[Means to solve the problem]

The semiconductor manufacturing apparatus according to the present invention is configured such that when plasma is generated, light or laser light is irradiated onto the surface of the semiconductor substrate, the region to be implanted with impurities, or the entire region or partial region of the plasma in the plasma doping device. be.

[Effect]

In the plasma doping method for semiconductor manufacturing equipment according to the present invention, when plasma is generated in the plasma doping apparatus, laser light is irradiated to the semiconductor substrate surface or the region to be implanted with impurities, or to the entire region or partial region of the plasma, so that the substrate surface reaction is prevented. The activation rate and dose increase, and a uniform shallow junction is formed.

〔Example〕

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

FIG. 1 is a side sectional view showing a plasma doping apparatus which is a semiconductor manufacturing apparatus according to an embodiment of the invention. In the figure, the same reference numerals as in FIG. 2 of the conventional example indicate the same parts, and 1
0 is an ArF laser.

The basic device structure is the same as the plasma etching device shown in FIG.

First, the gas introduced from the gas inlet 6 is A S Hi , Bz Hb diluted with an inert gas such as He. Next, plasma is generated between the upper and lower electrodes 2.3. At this time, the ions such as As'' and B'' generated are several hundred to several Ke
It is accelerated to approximately V and is implanted into the wafer 4. At this time, A
The ArF laser generated by the rF laser device 1o passes through the quartz window 5 and is irradiated onto the entire surface of the wafer 4 or into a partial region or into the plasma.

Here, the role of the ArF laser in the plasma doping apparatus will be explained.

FIG. 4 shows the implantation distribution during doping when doping is performed using a plasma doping apparatus according to an embodiment of the present invention.

As shown in the figure, in this embodiment, the ArF laser beam 14 is used to implant impurities into the plasma or the wafer surface, more specifically, the entire region of the plasma or a part of the plasma, the surface of the wafer 4, or the impurity of the wafer. It is designed to irradiate the desired area. When laser irradiation is performed in plasma, the energy decomposes non-ionized molecules existing in the plasma, increasing the amount of ions such as As'' and B'' existing in the plasma, and increasing the amount of ions per unit area. The number of implanted ions increases,
This leads to an increase in the density 13 of the implanted ionic species. Further, when the wafer surface is irradiated with laser light, the activation rate increases due to the excitation energy of the laser light, and the substrate surface reaction is promoted. Therefore, in this example, due to these effects, it is possible to shorten the process time, and at the same time, it is possible to prevent the adverse effects of the native oxide film existing on the wafer surface, which has been a problem in the past, and to improve the implantation distribution and implantation. Nonuniformity in the amount of ions can be sufficiently avoided, and the distribution of implanted ions within the substrate 4 can be made almost uniform.

In the above embodiment, two ArF lasers 10 are used, but one or more ArF lasers may be used several times.

Further, in the above embodiment, an ArF laser was used as the laser beam, but this may be a KrF laser or the like.

Other lasers may be used, and furthermore, other light beams such as ultraviolet light may be used instead of laser beams as long as the same effects as in the above embodiments can be obtained.

Further, in the above embodiment, the case where the laser device 10 is fixed is shown, but it may be equipped with a rotating mechanism, and in that case, the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, when performing doping by the plasma doping method, the plasma doping apparatus is configured to simultaneously use irradiation of the semiconductor substrate surface or plasma with an ArF laser, etc. Implant distribution without being affected by existing natural oxide films, etc.
It is possible to obtain a uniform injection amount and to obtain a desired injection amount in a short period of time.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view showing a plasma doping apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional side view showing a conventional plasma doping apparatus, and FIG. 3 is a doping process using a conventional plasma doping method. Schematic diagram of time, No. 4
The figure is a schematic diagram of doping when using the plasma doping method according to the present invention. In the figure, 1 is a reaction vessel, 2 is an upper electrode, 3 is a lower electrode, 4
is a wafer, 5 is a quartz window, 6 is a gas inlet, 7 is a gas exhaust port, 8 is a machining box, 9 is an RF power supply, 10 is an A
rF laser, 11 is injection distribution, 12 is natural oxide film, 13
is the density of the implanted ion species, and 14 is the ArF laser beam. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A semiconductor manufacturing apparatus that performs implantation using plasma in an impurity implantation process in the manufacture of semiconductor devices, and when performing implantation using the plasma, as well as generating plasma, light or laser light is emitted into the semiconductor substrate. 1. A semiconductor manufacturing apparatus characterized in that irradiation is applied to a surface or a region to be implanted with impurities, or to the entire region or a partial region of plasma.