JPS62142790A - Device for photoexcitation process - Google Patents

Abstract

PURPOSE:To efficiently form a dense deposited film having uniform film quality by constructing a vacuum reaction vessel of a device for photoexcitation process as a thin type reaction vessel having no ruggedness on the inside surface, supplying a reaction gas of stable laminar flow and suppressing the vapor phase reaction thereof. CONSTITUTION:The reactive gas is introduced through a gas introducing port 109 into the vacuum reaction vessel 101 having a discharge pipe 110 and a luminous flux 114 of light energy is irradiated from a high energy generating means 112 and optical system 113 via a light transmittable plate 102 disposed on the above-mentioned vessel 101 to the gas to deposit a thin film by the reaction with the surface of a wafer 104 heated to a prescribed temp. by a heater 106 for heating, a heat reflective plate 107, etc. The vacuum reaction vessel 101 of the device for photoexcitation process constituted in the above-mentioned manner is constructed as the thin type square reaction vessel having no ruggedness on the inside surface. The reactive gas is thereby supplied from the above-mentioned gas introducing port 109 made into a rectangular slit shape, etc., in the form of the uniform laminar flow into the surface of the wafer 104, by which a semiconductor device, etc., having the uniform film quality and thickness are formed.

Description

Detailed Description of the Invention [Technical Field to Which the Invention Pertains] The present invention relates to an apparatus for photoexcitation processes such as photoCVD (photochemical vapor deposition), photoetching, and photodoping, and more particularly, to semiconductor devices and Relates to optical excitation process equipment used in the manufacture of conductor integrated circuits, etc.

[1 Description of Prior Art] Conventionally, in the production of semiconductor devices and semiconductor integrated circuits, reactive gases are pumped using
1asser) or a low-J mercury lamp to generate active species, and there is a gas phase reaction between the generated active species and an interfacial reaction between the active species (ll'! to form a deposited film (so-called optical GVD)
), etching (so-called photo etching)
Methods using optical excitation processes, such as doping with impurity elements (so-called optical doping), are used. Various devices have been proposed for this purpose, including a vacuum reaction vessel equipped with a light-transmitting plate for introducing light, a means for introducing a reaction gas into the reaction vessel, and a means for introducing a reaction gas into the reaction vessel. It is equipped with a means for irradiating light and a means for evacuating the inside of the reaction vessel, and the shape of the vacuum reaction vessel is usually a tube furnace shape, a cylindrical shape, a cube shape, a pancake shape, etc. It has a wide reaction space above the wafers placed inside.

FIG. 3 is a schematic cross-sectional view showing an example of a conventional optical excitation process device. In the figure, 301 is a vacuum reaction vessel, 302 is a disc-shaped transparent plate made of quartz glass, etc.; 303 is for airtightness. A ring-shaped backing made of an elastic body provided with G, 3
o5 is the way/~ for installing way/304.
Stage 3 (J6 is a heater for heating the wafer. In this apparatus, the reaction gas is introduced into the chamber 301 through a gas supply pipe: 3o9 equipped with a valve 31). A high beam provided on one side of the transparent plate 302
from the energy generating means 312 to the optical system 313 such as a lens system,
and high energy light 314 through the transparent plate 302.
is irradiated with a reactive gas to generate active species. A chemical reaction such as film formation, etching, or doping occurs on the wafer surface due to a gas phase reaction between the generated active species, between the active species and undecomposed reaction gas, or a surface reaction between the active species and the wafer surface. . Reactive gases and active species not used in the reaction are discharged through an exhaust pipe 3 having a valve 31).
It is exhausted through 10.

As described above, in the conventional optical excitation processing apparatus, the reaction space A formed in the vacuum reaction vessel is formed as a large space above the wafer, making the entire apparatus bulky.

In addition, it is necessary to attach a light-transmitting plate 302 to the upper wall of the reaction vessel, but in order to maintain the vacuum inside the reaction vessel, the light-transmitting plate 302 is attached to the upper wall of the reaction vessel.
The attachment of step 2 requires precision, and as shown in Figure 2, it almost always results in the formation of irregularities on the inner surface of the upper wall of the reaction vessel.

If the inner surface of the chamber is uneven like this, the reaction gas released into the wide reaction space A through the gas supply pipe will become turbulent due to the unevenness of the inner surface of the reaction chamber, causing waving and reaching the surface. There is a problem in that it is difficult to supply a uniform reaction gas and to control the state of the reaction gas supply.

Furthermore, when introducing a reaction gas into the reaction space A through a gas supply pipe that is open at one end into the reaction container, a change in gas flow rate occurs due to rapid spread of the reaction gas into the space.
This may also occur due to the uniform supply of reaction gas to the surface of wafer 2 and the reaction gas supply condition.
It becomes a factor that inhibits lj expression.

In order to solve these problems, various methods such as devising the shape of the nozzle attached to the gas supply pipe, installing various gas distribution means, and immersing the gas flow path in the reaction vessel are used. have been proposed, but none of them can be considered complete.

Furthermore, since the waeno heater for promoting photochemical reactions is located inside the vacuum reaction vessel, the reaction gas is distributed randomly within the vacuum reaction vessel, which has a large reaction space, due to radiation and convection from the heater. This makes it even more difficult to uniformly supply the reactant gas to the surface of the wafer and to maintain the reactant gas supply state.

However, when a wide space is formed in the wafer and L portions as in conventional equipment, gas phase reactions occur relatively frequently, and in the formation of deposited films by photo-CVD, etc. Another problem is that it is difficult to obtain uniform film thickness and uniform film quality.

One more thing: Even if there are no irregularities on the inside of the vacuum reaction vessel, the inside of the reaction vessel other than the wafer surface or the inside of the transparent plate may come into contact with the chemical reaction, which is undesirable. The production speed of upper conductor devices and semiconductor integrated circuits may be reduced due to the formation of deposits and the poor light transmittance of the light-transmitting plate, and the uniformity of semiconductor devices and (1) conductor integrated circuits may be reduced. There is also the problem of a lack of sexuality.

[Purpose of the invention]

The present invention aims to solve the above-mentioned problems in optical excitation process equipment and to provide an equipment for efficiently manufacturing semiconductor devices and semiconductor integrated circuits having uniform film thickness and film quality. be.

That is, the main object of the present invention is to provide a photo-excitation process device that enables uniform reaction gas supply to a wafer by setting the flow of the reaction gas in a laminar flow state, and furthermore, provides a photoexcitation process device that enables the following: It is about providing.

Another object of the present invention is to provide an apparatus for a photoexcitation process that suppresses gas phase reactions in photochemical reactions and promotes surface reactions to produce homogeneous and uniform semiconductor devices or semiconductor integrated circuits. It is about providing.

[Structure of the invention]

The present inventors continued intensive research to solve the above-mentioned problems in conventional photoexcitation processing equipment, and found that the vacuum reaction vessel in this type of equipment was replaced with a thin reaction vessel, and the thin reaction It was found that by forming the inlet for the reactant gas into the container into a rectangular slit shape, the flow of the reactant gas could be made laminar. Further research revealed that by using a thinner vacuum reactor, the reaction space above the wafer can be narrowed, suppressing gas phase reactions in photochemical reactions and promoting surface reactions. found.

The present invention was completed through further research based on the above-mentioned findings. That is, the photoexcitation process apparatus of the present invention comprises a vacuum reaction vessel and a reactant gas introduced into the vacuum reaction vessel. In the apparatus for a photoexcitation process, the apparatus comprises: a means for irradiating a reaction gas with high-energy light through a transparent plate disposed in the vacuum reaction vessel; and a means for evacuating the inside of the vacuum reaction vessel. The vacuum reaction container is characterized by being a thin reaction container with no unevenness on the inner surface.

High-speed beams used in the optical excitation process equipment of the present invention
As the Luky light, those generated from all sources such as a mercury lamp, a xenon lamp, a carbon dioxide laser, an argon ion laser, a nitrogen laser, and an excimer laser are used.

In addition, the reaction gas used in the apparatus of the present invention is selectively introduced into the seeds of semiconductor devices and semiconductor integrated circuits to be manufactured. will be introduced.

The apparatus for optical excitation processing of the present invention having the above structure will be explained in detail below with reference to the embodiments shown in the drawings. Note that the present invention is not limited to the embodiments shown in the drawings.

FIG. 1 is a schematic cross-sectional view of an apparatus for a photoexcitation process of the present invention.

In the figure, 101 is a thin reaction container that forms a vacuum-sealed reaction space. Reference numeral 102 denotes a light-transmitting plate that constitutes a part of the first wall of the thin-type reaction container + 01, and the inner surface of the light-transmitting plate and the inner surface of the upper wall of the thin-type reaction container 101 are inverted so that they form the same plane. It has a truncated cone shape.

A groove is provided in the notch in the upper wall of the vacuum reaction vessel into which the transparent plate 102 is fitted, and a ring-shaped backing 103 made of an elastic material is placed in the groove to maintain airtightness.

10/l is a wafer placed on the wafer table 05, and 106 is a heating heater provided below the wafer table 105.

107 is a heat reflecting plate installed to reflect the heat of the heater. 109 is a gas inlet port provided on one side wall of the thin reaction container, and a notch is provided on the lower wall just before the other side wall, and an exhaust pipe 1) 0 is provided for exhausting the gas in the vacuum chamber. Connect, via valve Ill,
It is connected to an exhaust system (not shown). +12 is a high energy generation means, 1)3 is an optical system such as a lens system 1)・I
is high energy light.

In the apparatus of the present invention, the inner wall of the thin reaction vessel is made to have no unevenness, and the shape of the gas inlet 109 provided on one side wall of the reaction vessel is a rectangular slit that communicates with the thin rectangular reaction vessel. . The connecting portion of the thin rectangular chamber is shaped so that no level difference occurs.

By making the shape of the gas intake port and the shape of the inner wall of the thin rectangular reaction vessel as described above, the rapid diffusion of the reaction gas into the reaction vessel, which occurs when conventional nozzles are used, is eliminated, and the At the same time, the reaction gas introduced into the reaction vessel is passed through the gas inlet 10.
9 is supplied to the reaction space A in a laminar flow state.

That is, above the wafer, the gas streamlines are directed only toward the water/upward direction, the velocity distribution in the vertical direction Q is parabolic, with the fastest speed at the center, and the velocity distribution in the water-ri force direction is uniform. Therefore, it becomes possible to uniformly supply the reactive gas to the wafer surface and reproduce the reactive gas supply state.

More preferably, the gas flow path is as shown in FIG.
Form an upward arc with a gentle slope,
The flow rate of the reaction gas in the reaction space A+ is gradually reduced by G to allow a sufficient photochemical reaction to occur.

Furthermore, in order to prevent turbulence of the reaction gas caused by radiation and convection from the heating heater installed inside the wafer stage, the bottom wall of the thin rectangular reaction vessel other than where the wafer stage is installed is , it is desirable to perform cooling by piping a water cooling pipe 108. It is particularly preferable to provide such a cooling means, since by cooling the F wall other than one placement location of the wafer stage, the effect that no photochemical reaction occurs on the inner wall other than the wafer is achieved.

In the apparatus of the present invention, the vacuum chamber is a thin rectangular chamber, so the reaction space A formed on one side of the wafer becomes narrow, suppressing the gas phase reaction among the photochemical reactions and promoting the surface reaction. Optical CV using the device of the invention
When a deposited film is formed by the D method, there is also the effect that a dense thin film with uniform film quality can be stably obtained.

In Figure 1, the shape of the transparent plate is an inverted truncated cone in order to make the inner surface of the transparent plate that allows high energy light to pass through and the inner surface of the upper wall of the vacuum chamber to be on the same plane. However, as shown in FIG. 2G, the disc-shaped transparent plate 20
It is also possible to have a shape in which a stepped part is provided around the periphery (so-called edge) of 2. In FIG. 2, 201 is the upper wall of the vacuum chamber, 202 is a transparent plate with an edge that fits into the notch of the upper wall 201 of the vacuum chamber, and 203- is a ring-shaped elastic body attached to maintain airtightness. It's the backing.

Using the apparatus according to the embodiment of the present invention shown in FIG. 1, for example, amorphous silicon (hereinafter referred to as F.

[Written as a-3iJ. ) To form a deposited film,
This is done as follows.

In the case of forming an a-5i film, the reactive gases include gaseous ones such as silanes and halogenated silanes in which hydrogen, halogen, hydrocarbon, etc. are bonded to silicon, or Gasified substances that can be easily gasified can be used. These source gases may be used alone or in combination of two or more. In addition, these raw material gases may be used after being diluted with an inert gas such as He1 Ar.Furthermore,
The a-8i film can be doped with a p-type impurity element or an n-type impurity element, and a source gas containing these impurity elements as a constituent may be used alone or with the above-mentioned source gas or / and a diluting gas and can be introduced into the reaction space.

In addition, when two or more types of raw material gases are used, one or more of them may be used! 1) It is also possible to perform excited speciation beforehand and then introduce it into the reaction chamber.

First, in order to place the wafer J'lO=1 on the wafer stage 105 disposed in the thin reaction container, the transparent plate 102 is removed, and then the wafer stage 105 is driven. raised by a device (not shown);
The wafer stage 105 is pushed up into a part of the thin rectangular reaction vessel 101, and the pushed up wafer stage 105 is placed thereon.

Thereafter, the wafer stage is lowered, and the light-transmitting plate is fitted into a predetermined position on the upper wall of the thin-type reaction vessel, and attached by bolts or the like.

Next, the inside of the thin reaction vessel 101 is evacuated using an exhaust device (not shown), and the pressure inside the reaction vessel is reduced to 5×I.
O"' Torr or less, preferably lXl0" Torr
Let it be r.

Next, after premixing the reaction gases from each reaction gas supply source (not shown) to a predetermined composition ratio, the reaction gases are introduced from the gas inlet 109 into the reaction space A and the pressure inside the reaction space A is increased. t x t o-2 to I Torr. At the same time, high energy light generation means 1) 2
The high-energy light 1) 4 focused through the lens system 1) 3 is irradiated onto the reaction gas flowing in the reaction space A in a laminar flow state. The reaction gas is excited and decomposed by height energy light irradiation to become active species, and heated to 50 to 450°C, preferably 200 to 300°C, by heating heater.
A deposited film is formed on the wafer/-104 which has been heated and maintained at C. Among the reaction gases introduced into the reaction space Δ, undecomposed gases and active species not used to form the deposited film flow in the reaction space A in a laminar flow state and are exhausted through the exhaust pipe Ill. Ru.

After a predetermined period of time has elapsed, the irradiation with high-energy light, the introduction of raw material gas, and the heating by the heating heater are stopped, and the wafer is allowed to cool.Then, the wafer is removed by following the procedure reverse to that for placing wafer 1 described above. put out.

The example described above is for forming a deposited film by photo-CVD, but the apparatus of the present invention can also be used for photo-etching, photo-doping, etc. in addition to this example.

When used for photoetching, a mask having a predetermined pattern is placed between the transparent plate 102 and the wafer 104, and a high-energy light beam 4 passes through the mask and etches the wafer d'.
Photo-etching is made to occur only in the portion reaching the s surface. Also, when used for optical doping,
At the same time as introducing an impurity gas and photodecomposing it, the substrate is heated to diffuse the impurity into the substrate.

Furthermore, when the light-transmitting plate 102 is not provided and the upper wall of the vacuum reaction vessel is made without a notch, it can be used as an apparatus for dry processes other than optical excitation processes, and the present invention can also be applied in this case. By using a device using a thin reaction vessel, it is possible to form a laminar flow of the introduced gas,
Uniform gas supply to the wafer surface can be achieved.

rSummary of Effects of the Invention] The photoexcitation process device of the present invention uses a thin vacuum reaction vessel as a thin reaction vessel, eliminates unevenness on the inner wall of the reaction vessel, and has a rectangular slit-shaped gas inlet communicating with the reaction vessel. By doing so, it is possible to prevent sudden changes in gas pressure and flow velocity of the reactant gas, and to form a stable laminar flow without wave-like or eddy-like flow.When using the apparatus of the present invention, This makes it possible to uniformly supply the reactant gas to the Waeno surface and to change the state of the reactant gas supply. Moreover, in the apparatus of the present invention, the reaction space formed on one side of the wafer is narrow, so gas phase reactions can be suppressed and surface reactions can be promoted.
In the formation of a deposited film, a dense thin film with uniform film quality can be stably obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of the apparatus for optical excitation processing of the present invention, FIG. 1 is a schematic cross-sectional view showing an example of an apparatus for a photoexcitation process. In the figure, 101... Thin round reaction vessel, 201... Upper wall of thin reaction vessel, 301... Vacuum reaction vessel 102, 20
2.

Claims (4)

[Claims] (1) A vacuum reaction vessel, a means for introducing a reaction gas into the vacuum reaction vessel, a means for irradiating the reaction gas with high-energy light through a light-transmitting plate disposed in the vacuum reaction vessel, and a vacuum reaction vessel. 1. An apparatus for a photoexcitation process comprising a means for evacuating the inside of a reaction vessel, wherein the vacuum reaction vessel is a thin rectangular reaction vessel with no irregularities on the inner surface. (2) The means for introducing the reaction gas is a rectangular slit-shaped gas inlet, and there is no step at the joint between the gas inlet and the inner surface of the thin rectangular reaction vessel. Equipment for photoexcitation process. (3) The shape of the transparent plate is an inverted truncated cone, and it is arranged so as to constitute a part of the upper wall of the thin rectangular reaction vessel, and the inner surface of the thin rectangular reaction vessel and the inner surface of the transparent plate are flush with each other. An apparatus for a photoexcitation process according to claim (1) or (2), which is configured to: (4) The shape of the light-transmitting plate is a circular plate with a stepped periphery, and it is arranged so as to constitute a part of the upper wall of the thin rectangular reaction vessel, and the light-transmitting plate is connected to the inner surface of the thin reaction vessel. An apparatus for a photoexcitation process according to claim 1 or 2, wherein the inner surface of the plate is flush with the inner surface of the plate.