JPS6294938A - Photo exciting surface processor - Google Patents

Abstract

PURPOSE:To enable a substrate with large diameter to be surface processed evenly by photo-irradiating the overall surface thereof and feeding it with gas evenly by a method wherein a hollow disc provided with gas jetting holes on the surface opposing to the substrate surface as well as a photo-transmitting part in the central part is used. CONSTITUTION:A hollow disc 14 opposing to the surface of substrate to be processed is arranged on the upper part of a vacuum vessel 11 while a small vertical through hole 15 is made in the central part of hollow disc 14. Then specified gas is led into the hollow part of disc 14 from gas leading-in pipes 17 to be fed to the surface of substrate 12 through gas jetting holes 16 of the disc 14. On the other hand, a photo-transmitting window 23 is provided on the upper wall of vessel 11 while a light source 21 and a lens 22 are respectively arranged above the window 23. Then the overall surface of substrate 12 to be processed is irradiation with the light 24 from the light source 21 once converged by the lens 22 on the point around the small hole 15. Through these procedures, the evenness of etching process by photo-excitation can be improved further making it feasibeeto perform anisotropic etching process doing no irradiation damage to any charged particles.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to the manufacturing of semiconductor devices and other surfaces Ij! The present invention relates to surface treatment technology for materials in the field of microfabrication, and in particular to a photoexcitation surface treatment device that utilizes light irradiation.

[Technical background of the invention and its problems]

In recent years, a so-called photo-excited dry etching method, which uses light to excite gas, has been attracting attention as one of the dry etching techniques. With this method, there is only 1! ! Particles with high transport energy that would damage the substrate are not generated, and a high-quality surface is maintained even after treatment.

Furthermore, in the photo-excited dry etching method, a technique has been proposed in which 1111 of organic matter is formed on the surface of a substrate to be processed, and the 1111 thereof is directionally removed by light irradiation to perform anisotropic etching. This method allows anisotropic etching without any radiation damage.

However, this type of method has the following problems. That is, in order to uniformly etch the entire surface of a large-diameter wafer (substrate to be processed), it is necessary to uniformly supply an etching gas or a mixed gas of an etching gas and a deposition gas to the wafer surface. will be the biggest challenge. Typically, photo-excited etching is performed using 0.1 [to
The process is carried out under a relatively high gas pressure of more than 100%, and therefore, viscous fluid must be handled for the gas supply. As an example of a reactive ion etching apparatus that is handled in a similar manner, there is an etching apparatus A2 in which parallel plate electrodes 63 and 64 are disposed within a vacuum chamber 61, as shown in FIG. This is because A2 easily reacts with C20 and is etched, so etching is performed by uniformly supplying a large amount of gas to the surface of the wafer 62 through a small hole 66 formed in the upper electrode 64. However, in photo-excited etching, it is necessary to irradiate light from above the wafer, and such a configuration is not possible.

Therefore, the present inventors devised a configuration in which the gas supply portion is removed from the optical path and gas is ejected from an annular quartz tube 67, as shown in FIG. Incidentally, in FIG. 7, 68 indicates a gas introduction pipe, and 69 indicates a light transmission window. However, as a result of experiments conducted by the present inventors, it was found that even with this configuration, when a large amount of gas is supplied to a large diameter wafer, the etching uniformity becomes extremely poor.

The above-mentioned problem is not limited to etching, but also applies to film formation using light irradiation, cleaning treatment, and other surface treatments.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to be able to irradiate the entire surface of a substrate to be treated with light, to uniformly supply gas to the surface, and to use a large-diameter substrate. A light excitation surface treatment device that can perform surface treatment with good uniformity on the substrate to be treated! ! ! It is about prosperity.

(Summary of the Invention) The gist of the present invention is to uniformly supply gas to the surface of the substrate to be processed from a hollow disk disposed facing the surface of the substrate to be processed, and to pass a small amount of light through the center of the hollow disk. The purpose is to provide a section and irradiate the entire surface of the substrate to be processed with light through this light passage section.

That is, the present invention comprises a container for accommodating an m-treated substrate, a gas introducing means for supplying a predetermined gas into the container, a means for evacuating the inside of the container, and a means for irradiating the surface of the substrate with light. In the optically excited surface treatment apparatus, the gas introducing means is arranged to face the surface of the substrate, a plurality of gas ejection holes are provided on the surface facing the substrate surface, and a light passage part is provided in the center. Using the provided hollow disc body,
A predetermined gas is introduced into the hollow part of the disc body, and the gas is supplied to the surface of the substrate through the gas ejection hole of the disc body, and the light passing part of the disc body is used as the light irradiation means. The entire surface of the base body is irradiated with light through the base body.

〔Effect of the invention〕

According to the present invention, gas can be uniformly supplied to the surface of a substrate to be processed even if the hollow disk body is disposed opposite to the surface of the substrate. Furthermore, the entire surface of the substrate to be processed can be irradiated with light through the light passage portion of the disc body. Therefore, even if the substrate to be treated has a large diameter, it is possible to perform surface treatment with good uniformity.

Furthermore, when applied to etching, the surface of the substrate to be processed can be irradiated with light substantially perpendicularly, making it possible to perform photoexcited anisotropic etching using the directionality of light. Additionally, improved etching uniformity results in reduced overetching time and improved productivity. Further, there is an advantage that the etching shape of the substrate to be processed can be prevented from deteriorating (undercutting occurs) during over-etching.

[Embodiments of the invention] Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic diagram showing a photoexcitation etching apparatus according to an embodiment of the present invention. In the figure, reference numeral 11 denotes a vacuum container, and a susceptor 13 for holding the substrate 12 to be processed is accommodated in the container 11.

Although not shown, the susceptor 13 is provided with a temperature control mechanism for keeping the temperature of the substrate 12 constant (for example, about 50° C.). Further, a hollow disc body 14 is arranged at the upper part of the container 11 so as to face the surface of the substrate 12 to be processed. A small hole (light passage section) 15 is provided in the center of the hollow disc body 14, passing through in the vertical direction. Roughly speaking, a plurality of gas ejection holes 16 are provided on the lower surface of the disc body 14. In the periphery of the disc body 14,
A gas introduction pipe 17 penetrating the side wall of the container 11 is connected. Then, a predetermined gas is introduced into the hollow portion of the disc body 14 from the gas introduction pipe 17, and the gas is supplied to the surface of the substrate 12 to be processed through the gas ejection holes 16 of the disc body 14. Furthermore, the gas in the container 11 is exhausted through a gas exhaust port 18.

On the other hand, a light transmitting window 23 is provided in the clay wall of the container 11. Above this window 23, a light source 21 and a lens 22 are respectively arranged. The light source 21 has a wavelength of 30, for example.
8 [nm] XeCρ excimer laser emitter.

The light 24 from the light source 21 is once focused near the small hole 15 of the disk body 14 by the lens 22, and then is irradiated onto the entire surface of the substrate 12 to be processed.

Note that 25 in the figure indicates a vacuum seal member.

FIG. 2 shows the structure of the gas introduction groove, which is a feature of this embodiment, and is a sectional view when viewed from above in FIG. 1.

The hollow disc body 14 and the gas introduction pipe 17 may be made of any material as long as it is resistant to the gas used, but quartz is preferable in consideration of contamination of the substrate 12 to be processed. In order to obtain uniformity within the hollow disc body 14, the gas introduction pipes 17 are preferably provided in at least two directions as shown.

Gas entering the hollow portion of the disk body 14 through the gas introduction pipe 17 is introduced into the container 11 through a gas ejection hole 16 formed on the surface facing the substrate 12 to be processed. The size, number, and arrangement of the gas ejection holes 16 may be optimally set depending on the etching conditions, that is, the type of gas, the pressure, the distance to the substrate to be processed, and the like. Further, it is desirable that the small hole 15 provided in the center of the disk body 14 be made large as long as it does not disturb the uniformity of gas supply. Further, it is preferable to provide a gas ejection hole 16 on the side wall of this hole 15 so that gas can be supplied from the center as well.

Next, the operation of the apparatus configured as described above will be explained.

First, as the substrate 12 to be processed, as shown in FIG. 3(a), a substrate is used in which a SiO2 film 32 and a phosphorus-added poly 5i 133 are formed on a 3i substrate 31, and an etching mask 34 is further formed on the poly 5in 133. there was. The gas introduced into the container 11 is C as an etching gas.
I! , 2 and Si(CH3)4 as a deposition gas was used. Further, the light irradiated onto the substrate 12 to be processed was XeC excimer laser light with a wavelength of 308 [nm].

Under the above conditions, Cj22 molecules, which are the etching gas, are dissociated by light irradiation to become active 0° C. atoms, etching the poly-5i133. In addition, C atoms react with Si (CH3)4 molecules, which are the deposition gas, to form Si (CHI)xcffi4-x (X = 1 to 3).
Reaction products such as are formed. Here, the above-mentioned reaction product starts to vaporize at about 50 [°C] by heating in vacuum, and almost all of its components evaporate at 100 [°C]. Therefore, as shown in FIG. 3(b), the reaction product is less deposited in the area irradiated with light from above, and etching progresses in this area. On the other hand, the intensity of the irradiated light is weak on the sidewall of the pattern below the etching mask 34, and a thin deposit 1jA35, which is the reaction product, is formed on this sidewall, preventing the generation of undercuts from the etching species (C2 atoms). becomes.

In this way, by applying light from above and using the deposited film, poly5ifi! is formed as shown in FIG. 3(C). PolySi! 133 anisotropic etched shapes could be achieved.

Here, it is known that the poly S1 is etched by spontaneously reacting with the C atoms, and that the etching rate is proportional to the pressure of the CI2 atom gas. Therefore, poly 5ill! on the entire surface of the wafer (?!!!! processing substrate 12)! When etching J, it is necessary to provide an equal amount of CJ2 atoms to each point on the wafer to obtain uniformity.

Figure 4 (a> is SUS tube-4 with a diameter of 1 [cm]
This is an example in which C1tt atoms excited in advance from No. 4 are supplied to the wafer for etching. Here the arrows indicate the flow of gas.

The graph below shows the etching rate distribution at several points on the wafer. It can be seen that the uniformity of etching is extremely poor. This is due to the fact that the amount of 0° C. atoms supplied differs greatly between the center and the periphery of the wafer, and also that Cρ atoms recombine to form 022 molecules around the wafer.

On the other hand, when the hollow disk body 14 is used as in this example, it has been confirmed that the uniformity within the wafer surface can be suppressed to approximately 5%. This is due to the fact that Cλ atoms could be uniformly supplied to the entire wafer surface. In addition,
In this case, since only C2 atoms are used, the etched shape is isodirectional.

Therefore, by irradiating light through the small holes 15 of the disc body 14 using the method of adding the deposition gas described above,
Anisotropically etched shapes can be achieved with good uniformity.

As described above, according to the present embodiment, by using the hollow disc body 14 having the small holes 15 for passing light and the gas ejection holes 16, it is possible to irradiate the entire surface of the substrate 12 to be processed with light. gas can be uniformly supplied to the surface. Therefore, it is possible to improve the uniformity of etching due to optical excitation. Furthermore, it becomes possible to anisotropically etch phosphorus-doped poly-Si without damaging it by irradiation with charged particles, and its usefulness is enormous.

FIG. 5 is a schematic configuration diagram showing the main part configuration of another embodiment of the present invention. Note that the same parts as in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

This embodiment differs from the previously described embodiments in that the hollow disc body 14 is provided outside the container 11. That is, the hollow disc body 14 is fixed to the upper wall of the container 11 so as to close the opening provided therein. Here, since the upper plate 54 of the disc body 14 is used also as a light transmission window, it needs to be a member that transmits light. Further, the small hole 15 for allowing light to pass through is formed in a tapered shape that expands downward.

Of course, even with such a configuration, the same effects as in the previous embodiment can be obtained. Further, in this embodiment, since gas can be supplied to the hollow disc body 14 in the atmosphere,
The device is easier to manufacture. Furthermore, the seal member 25
This has the advantage of reducing the number of locations that require

Note that the present invention is not limited to the embodiments described above. In the example, anisotropic etching using a deposited film was explained, but additive-free poly-Sl was used.

In metal silicide such as MO8iz, etching progresses only in the portions irradiated with light, so etching can be performed with good uniformity over the entire surface of the wafer without using a deposition gas. Furthermore, the present invention is not limited to etching.
Of course, it can also be applied to deposition using optical excitation. Even in deposition, uniform supply of gas is essential, and the present invention is extremely effective when applied to photo-CVD and the like.

Furthermore, it goes without saying that the present invention can also be applied to cleaning the surface of a substrate to be processed.

Also, the material of the hollow disk body as a gas introduction mechanism.

Conditions such as the number of gas ejection holes and the size of the small hole as the light passage section may be adjusted as appropriate depending on the specifications.

Furthermore, the wavelength of the light used, the type of gas, etc. can be changed as appropriate depending on the material to be treated. In addition, various modifications can be made without departing from the gist of the present invention.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic configuration diagram showing a photoexcitation etching device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the configuration of main parts of the device, and FIG. FIG. 4 is a process sectional view for explaining the etching method used, and FIG. 4 is a schematic diagram for explaining the operation of the above embodiment and shows the change in etching rate with respect to the wafer position. FIG. FIGS. 6 and 7 are schematic diagrams showing the configuration of the main parts of the embodiment, and FIGS. 6 and 7 are schematic diagrams showing the conventional apparatus, respectively. 11... Vacuum container, 12... Substrate to be processed, 13...
・Susceptor, 14...Hollow disk body, 15...Small hole (
light passage part), 16... gas blowout hole, 17... gas introduction pipe, 18... gas exhaust port, 21... light source, 22
... Lens, 23 ... Light transmission window, 31 ... 3i substrate, 32 ... S i , :) 2 m, 33-!
J > Addition Ho'J Si vA, 34... Etching mask, 35... Deposited film. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 5 Figure 3

Claims (5)

[Claims] (1) A container for accommodating a substrate to be processed, and a hollow space that is arranged to face the surface of the substrate, has a plurality of gas ejection holes on the surface facing the substrate surface, and has a light passage section in the center. a gas introduction mechanism consisting of a disc body, which introduces a predetermined gas into a hollow part of the disc body and supplies the gas to the surface of the substrate through a gas ejection hole of the disc body; A photoexcitation surface treatment apparatus comprising: means for irradiating light onto the entire surface of the substrate through a light passage section; and means for evacuating the inside of the container. (2) The optically excited surface treatment apparatus according to claim 1, wherein the light passage portion of the gas introduction mechanism is a small hole formed in the center of the disc body. (3) The optically excited surface treatment apparatus according to claim 1, wherein the light irradiating means is configured to focus light from a light source near a light passage portion of the gas introduction mechanism using a lens. (4) The photoexcitation surface treatment apparatus according to claim 1, wherein the surface of the disc body opposite to the surface on which the gas ejection holes are formed is formed of a quartz plate. (5) The outer diameter of the disk body is approximately equal to the outer diameter of the substrate to be processed.
The optically excited surface treatment device described in 2.