JPS59209642A - Vapor phase formation of thin film - Google Patents

Abstract

PURPOSE:To form a dense thin film excellent in adhesion strength with high reliability, by continuously performing etching a sample substrate and the adhesion of a thin film in the same gas vessel, and controlling the position of adhesion and the thickness of the film. CONSTITUTION:Sample substrates 1a, 1b are mounted on a rotary table 2 inside a gas vessel 6, adsorptive exhaustion is performed through exhaust openings 7, 8, Ar gas is supplied through supply openings 9, 10, DC voltage is impressed on discharge electrodes 4a, 4b, and the surfaces of the substrates 1a, 1b are etched by sputtering. Then, the relative positions of the substrates 1b, etc. against a condensing optical part 13 are controlled by a microscopic optical system 12, to perform positioning. A material gas containing a gaseous compound is newly supplied through a supply opening 14, Ar gas is supplied through the supply openings 9, 10, and laser beams 17 are applied through the condensing optical part 13 and a window 15 onto the desired parts of the substrates 1b, etc. while performing exhaustion through the exhaust openings 7, 8. Hence, a thin film is formed. Hereon, the laser beams permeating through the substrates 1b, etc. are detected by a detector 18, and the thickness of the film is controlled by a controller 19 to obtain a desired thin film.

Description

[Detailed Description of the Invention] The present invention consists of: 1. Using energy rays such as ultraviolet and extraterrestrial radiation, a compound gas is separated by PJ, and a desired substance is deposited on a sample substrate to form a thin film. The present invention relates to a vapor phase thin film formation method.

In recent years, with the rapid development of electronic components such as semiconductors, I
Techniques for forming films of metals, semiconductors, insulators, etc., such as modifying photomasks for C, forming electrodes on transparent substrates for display elements, and forming insulating films and electrical wiring layers for integrated circuits. It has become much needed. In particular, the laser vapor phase thin film formation method, in which a raw material gas containing a compound gas is irradiated with laser light, thereby dissociating the compound gas and forming a film by coating a desired substance on a sample substrate, uses laser light. By skillfully utilizing the high brightness and condensing properties of light, it is possible to form a thin film locally and quickly at a desired location on the sample substrate, making it possible to lower the process temperature. Together, these methods have been actively attempted in recent years.

However, this conventional method for forming a vapor phase thin film of yuzu has the following problems. In other words, it is often necessary to perform various tests on the sample substrate in the atmosphere, or to wash off oils and fats attached to the sample substrate9.
Even if you try to form a thin film in the gas phase by putting a sample substrate that has been taken out into the atmosphere into a gas tank using conventional methods, it is not possible to obtain a good quality thin film, and even if the thin film does not adhere However, the adhesive strength was not always sufficient.

This is because the surface layer of a sample substrate placed in the atmosphere is layered with chemical substances such as oxygen and water vapor in the atmosphere, which have changed into chemical compounds and hydroxides, as well as aerosols floating in the atmosphere. This is thought to be due to the fact that the surface layer of the substrate is significantly contaminated. That is, on such a contaminated and altered surface layer, the irradiated product tends to form non-uniform granular lumps in the initial process of adhesion, making it difficult to obtain a dense thin film.

An object of the present invention is to provide a highly reliable thin film forming method that can eliminate these conventional drawbacks and form a dense thin film with strong adhesion strength.

In order to achieve the above object, the present invention includes an etching process in which a sample substrate is exposed to an inert gas atmosphere and the surface layer of the sample substrate is etched by discharging the inert gas, and after the etching process, the sample substrate is exposed to the outside air. The sample substrate is covered with a raw material gas containing a compound gas without being exposed to heat, the compound gas is dissociated by irradiation with energy rays, and the desired substance generated by this dissociation is covered at a desired position on the surface of the sample substrate. It has a structure that includes a vapor phase deposition step.

Hereinafter, this invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. The configuration of an embodiment in which the invention is applicable is shown.

In FIG. 1, a plurality of sample substrates 1a, lb, . By rotating this rotary table 2, the sample substrates 1a, lb... are transferred to the discharge electrodes 4a, 4b.
can be transported into the discharge space 5 created by
! It can also be transferred to the oral area.

First, sample substrates la and lb placed on the rotary table 2
Etching by gas discharge is carried out to obtain a clean surface for... For this purpose, the gas in the gas tank 6 is sucked in and exhausted through the air lower and 8, and Ar gas is supplied as an inert gas to the shigasu cypress 6 through the inert gas supply ports 9 and 10.

In this embodiment, a DC voltage is applied between the discharge electrodes 4a and 4b, and the surfaces of the sample substrates 1a, 1b, . . . are etched using sputtering caused by the DC discharge. The diameter of the discharge electrodes 4a, 4b is about 15 Crn, and the electrode spacing is about 2.5 cm. The pressure of Ar gas in the gas tank 6 is set to about 5 Torr, and the pressure of the Ar gas in the gas tank 6 is set to about I KV from the power supply 11.
By applying a voltage of %4 between them and causing a discharge, the surfaces of the sample substrates 1a+1b... inserted into the discharge space are sputtered, and the surface layer and other parts that have changed in quality when placed in the atmosphere are sputtered. Laminated contaminants and the like are removed from this surface, resulting in a clean surface. Since the depth from the surface of the surface layer removed by this etching process is approximately proportional to the current application time, the etching depth can be adjusted by controlling the current application time. If the energization time is too long, the morphology of the surface becomes rough, so in order to obtain a peaceful and clean surface, it is necessary to set the energization time to be optimal.

Sample substrates 1a, lb...K are cleaned to obtain cleanliness.

Once the coating process is completed, the next step is the vapor phase deposition process. The surfaces of the sample substrates 1b, etc. are observed using the microscopic observation optical system 12. Setting a vapor phase deposition site at a desired position on the sample substrate by driving the light source section 13 and controlling the relative position between the light collection optical section 13 and the sample substrate 1b, etc. I can do it.

A source gas containing a compound gas is newly supplied onto the sample substrate (ib in the figure) on which the vapor phase deposition site is set by opening the source gas supply port 14. Ar gas is continuously supplied as an inert gas into the gas tank 6 from the inert gas supply pipes 9 and 10 to prevent contamination of the quartz glass window 15 and the surface of the sample substrate. Furthermore, as disclosed in Japanese Patent Publication No. 57-154839, the window 15 may be coated with a film made of perfluorinated polyether in advance to prevent undesirable substances from adhering to the window 15. This is to prevent the transmittance of the window 15 from decreasing as much as possible. Gas tank 6 is a suction exhaust lower.

Fresh gas always flows into the gas tank 6 by evacuating the gas by valve 8.

Reference numeral 16 indicates a part of the laser beam irradiation device. The laser beam 17 is emitted from the laser beam irradiation device by activating the condensing optical section 13, enters the gas tank 6 through the window 15, and irradiates a desired region on the surface of the sample substrate 1b. In this example,
Using an ultraviolet laser beam C with a wavelength of 350 nm or less as the laser beam 17, using Cr(Co) as the compound gas, and setting the partial pressure of Cr(Co')6 on the surface of the sample substrate 1b to be approximately I Torr, By setting the irradiation light intensity of the laser beam 17 to about 10" W/cA, a strong and dense ROM thin film can be deposited on the white spot (pinhole) defective part of the chrome mask used as the sample substrate 1b. did it.

When depositing an opaque substance such as chromium onto a sample substrate, the rate of formation of a thin film by vapor phase deposition can be determined by measuring changes in the intensity of laser light that passes through the sample substrate. Therefore, in this embodiment, the sample substrate 1b
A photodetector 18 detects the laser beam that has passed through the film, and transmits this output to a film thickness controller 19 . The film thickness controller 19 calculates the thin film formation rate from the rate of change in the signal output from the photodetector 18, and when the signal output from the photodetector 18 decreases to a certain predetermined intensity or less, the thin film formation rate increases. After setting a predetermined delay time determined by
7. Stop the irradiation. This allows a thin film of desired thickness to be deposited.

FIGS. 2 and 3 are block diagrams showing the configurations in the etching process and vapor phase deposition process of the second embodiment 1 of the present invention, respectively. In this embodiment, a case will be described in which the present invention is applied to correcting white spot (pinhole) defects in a photomask in which a metal such as chromium is deposited on a transparent glass substrate.

In the figure, a sample substrate 21 is held in close contact with a substrate holder 22. The substrate holder 22 is rotated by the shaft 2
By rotating the sample substrate 21 in the third direction, the direction of the substrate surface of the sample substrate 21 can be changed from the horizontal direction (Fig. 2) to the vertical direction (Fig. 3).
It is also possible to change the appearance from vertical to horizontal.

First, as shown in FIG. 2, the surface of the sample substrate 21 is oriented horizontally, and etching is performed using gas discharge to obtain a clean surface. Therefore, the gas in the gas tank 24 is exhausted from the suction/exhaust port 25, and the 10-' Tor
r After obtaining a high degree of vacuum of 8 degrees, a small amount of inert gas is supplied into the gas cylinder 24 through the inert gas supply port 26. In this embodiment, a voltage is applied between the discharge electrodes 27a and 27b, and the surface of the sample substrate 21 is etched using sputtering by direct current discharge. The diameter of the E-IA electrode is about 15 tln, and the electrode spacing is about 10c! It is n.

Ar gas is supplied as an inert gas into the gas tank 24, and the pressure inside the gas tank 24 is set to about 5 Torr. ′
By applying a voltage of approximately 4 KV between the electrodes from the power supply 28, the surface of the sample substrate 21 facing the direction of the applied electric field is anisotropically sputtered, and when the sample substrate 1 is placed in the atmosphere. The degraded surface layer and adsorbed contaminants are effectively removed from this surface, resulting in a clean surface. Since the depth from the surface of the surface layer removed by this anisotropic etching step is approximately proportional to the current application time, the etching depth can be adjusted by controlling the current application time. If the energization time is too long, the surface morphology will become rough, so care must be taken to set the optimum energization time in order to obtain a flat and smooth surface.

After the etching process for cleaning the surface of the sample substrate 21 is completed, a vapor phase deposition process follows. As shown in FIG. 3, the substrate surface of the sample substrate 21 is oriented vertically and substantially parallel to the direction of incidence of the laser beam 290 entering the gas tank 24. As shown in FIG.

The surface of the sample substrate 21 is observed using a fine sand detector and an optical system 210. Driving the condensing optical section 211, the condensing optical section 21
By controlling the relative position between 1 and the sample substrate 21,
A vapor phase deposition site can be set at a desired position on the sample substrate.

A source gas containing a compound gas is newly supplied onto the sample substrate 21 on which the vapor phase deposition site is set via the source gas supply port 212 . In order to prevent contamination of the quartz glass window 213 and to prevent contamination of the back surface of the sample substrate, Ar gas is supplied as an inert gas into the gas tank 24 from inert gas supply ports 214 and 26, respectively. . Also, window 2
13, as disclosed in Japanese Unexamined Patent Publication No. 57-154839, a film made of perfluorinated polyether is applied in advance to prevent undesired substances from adhering to the window 213. , a decrease in the transparency of the window 213 is prevented as much as possible. Fresh gas always flows into the gas tank 24 by sucking and exhausting the gas in the gas tank 24 through a suction/exhaust port 25.

Reference numeral 215 indicates a part of the laser beam irradiation device.

The laser beam 29 is emitted from the laser beam irradiation device via the condensing beam portion 211, enters the gas tank through the window 213, and irradiates a desired portion on the surface of the sample substrate 210. In this example, an ultraviolet laser beam with a wavelength of 350 nm or less is used as the laser beam 29, and Cr (C
o) Cr(co) on the surface of the sample substrate 210 using 6
By setting the partial pressure of the laser beam 29 to about I Torr and the irradiation light intensity of the laser beam 29 to about 103 W/ca, a strong and dense layer is formed in the white spot (pinhole) defect of the chrome mask used as the sample substrate 21. I was able to apply a pattern on the river.

When depositing an opaque substance such as chromium on a transparent sample substrate such as a glass substrate, by determining the intensity change of the laser beam passing through the sample substrate,
The rate of thin film formation due to vapor phase deposition can be determined. Therefore, in this embodiment, the laser beam transmitted through the sample substrate 21 is detected by the photodetector 216, and the output thereof is transmitted to the controller 217. This film thickness controller 2
17 calculates the rate of change in the signal output from the photodetector 216, and when the signal output from the photodetector 216 attenuates to a predetermined intensity or less, the rate of change in the rate of change in the signal output from the photodetector 216 decreases to a predetermined rate determined by the rate of formation of the tunica. After providing a delay time of , the irradiation of the laser beam 29 is stopped. Thereby, a film having a desired thickness can be deposited on the surface of the sample substrate 10.

As described above, according to the present invention, by sequentially performing the etching process and the vapor deposition process, a dense, high-quality thin film with strong adhesion strength can be locally formed on the sample substrate. It was possible to form the photomask with high reliability, and it was possible to repair defects in the photomask with high reliability.

In this embodiment, the defect correction of a photomask has been described, but this is only one embodiment of the present invention. For example, as a compound gas, SiH, GeH4
By using a mixed gas of SiH4 and NH, semiconductors such as Si and Ge, Si3N,
It is possible to form a lake film of an insulator such as. In addition, in addition to Cr(Co), metal carbonyl compounds such as W(Co)6, MO(Co)6, Mo(C6H6)2, Cr(
Metal complex compounds such as C6H6)2, Cd(CH3)2
．． A variety of compound gases can be used, including organometallic compounds such as At(0M3)3.

Note that it is preferable to use a laser beam as the energy beam from the point of view of local selectivity, as in this example.
In cases where local selectivity is not so required, light emission from a lamp or light emission from plasma can also be used. When using a laser beam, it is desirable to select its wavelength depending on the type of compound gas.

Further, in the real Ni array of the present invention, sputtering using direct discharge of an inert gas was used in the etching process, but sputtering using high frequency radiation (microwave frequency) may be used instead.

In particular, when using microwave discharge, the use of a waveguide allows discharge to be performed without electrodes, thereby allowing clean etching with less generation of impurities. In addition, by adopting magnetic confinement using magnetic coils, a stable discharge plasma flow with excellent directionality can be obtained, making it possible to perform effective anisotropic etching and obtain high-quality clean surfaces in a short time. It becomes easier to perform high-quality cleaning and film formation.

In this embodiment, the substrate holder 22 held a single sample substrate 21, but instead, a plurality of sample substrates were held, and the substrate holder 22 was connected to the rotating shaft 23.
By moving the sample substrates parallel to each other, it becomes possible to sequentially perform an etching process and a vapor deposition process on the plurality of sample substrates.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a first embodiment of the present invention. In the figure, 1a, 1b... are sample substrates, 2 is a rotating table, 3 is a rotating shaft, 4a, 4b are discharge electrodes, 5 is a space between discharge walls, 6 is a gas tank, 7, 8 are suction and exhaust ports, 9 , 10 is an inert gas supply port, 11 is a source, 12 is a microscope, 13 is a condensing optical part, 14 is a raw material gas supply port, 15 is a window, and 16 is a part of a laser beam irradiation device. , 17 is a laser beam, 18 is a photodetector, and 19 is a film thickness controller. FIGS. 2 and 3 are block diagrams showing the configurations in the etching process and vapor phase deposition process, respectively, of a second embodiment of the present invention. In the figure, 21...sample substrate, 22...substrate holder, 23...rotating shaft, 24...gas tank, 2
5... Suction/exhaust port, 26.2 Nu4... Inert supply port, 27a, 27b... Discharge electrode, 28. Power supply, 29...
・Laser light, 210...avhy optical system, 211・
・Condensing optical part, 212-raw material gas supply port, 213...
Window, 215... Part of laser beam irradiation device, 216.
Photodetector, 217... Film thickness controller. Representative Patent Attorney Susumu Uchihara Diagram 2

Claims (1)

[Claims] (1) An etching process in which the sample substrate is exposed to an inert gas atmosphere and the surface layer of the sample substrate is etched by discharging the inert gas, and after the etching process, the sample substrate is exposed to a compound gas without being exposed to the outside air. A vapor phase deposition step in which the sample substrate is covered with a raw material gas containing , the compound gas is dissociated by irradiation with energy rays, and the desired substance produced by this separation is coated at a desired position on the surface of the sample substrate. A vapor phase thin film formation method characterized by: