JPS6080803A - Production of optical waveguide - Google Patents

Abstract

PURPOSE:To form the pattern of optical waveguides by making a beam for reaction incident in parallel with a substrate and a beam for heating incident perpendicularly thereto and controlling the intersected region of these beams to deposit a thin film generated by photoinduced reaction with a gaseous reactant or said reactant and precursor material contg. oxygen to the substrate. CONSTITUTION:A beam 2 for reaction of diffusion is made incident in parallel with a substrate 1 and a beam 3 for heating is made incident perpendicularly thereto. The intersected region of the beams 2, 3 is controlled to deposit a thin film 4 generated by photoinduced reaction with the gaseous reactant alone or said reactant and precursor material contg. oxygen on the substrate 1. Molecules contg. Si, B, Ge, Al, P, etc. are used for the gaseous reactant and N2O, NO2, NO, etc. are used as the precursor material contg. oxygen. A gaseous material for sensitizing photodissociation reaction is added to the substrate atmosphere to increase the rate of depositing the thin film. The shape and irradiating positions of the beams 1, 2 are further changed to change the depositing position and shape. The thin films having different compsn. are formed by changing the material and concn. of the substrate atmosphere. Various kinds of photoelements are thus integrated on the same substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing an optical waveguide in which an optical waveguide is patterned and formed on a substrate.

[Prior Art] Conventionally, as a technique for selectively forming optical waveguides and integrating waveguides formed from different compositions, there has been a technique using a resist and etching process, as seen in the integrated circuit manufacturing process. There was something. However, according to such a manufacturing method, a large number of steps are required depending on the composition: - thin film formation - resist coating - pattern transfer - visual image - etching - resist removal.

Furthermore, when forming waveguides with different compositions, it is necessary to accurately align the waveguides during pattern transfer. However, the method of creating a large number of waveguides having different compositions requires many steps and is complicated, which has been an obstacle to improving mass productivity.

In addition, the degree of freedom in material selection is determined from various viewpoints, including resistance to chemicals used in resist and etching processes, and whether or not there is a method for forming a thin film with the multicomponent composition required to obtain the desired refractive index. This has been a major problem in creating optical waveguides with good characteristics.

[Objective] In view of the above-mentioned points, a first object of the present invention is to provide a method for manufacturing an optical waveguide that eliminates many processes and improves mass productivity.

A second object of the present invention is to provide a method for manufacturing an optical waveguide that uses a dry process to expand the range of usable materials and exhibits good characteristics.

[Structure of the Invention] In order to achieve the above object, the present invention provides a method for manufacturing an optical waveguide by forming a thin film on a substrate, in which a first light beam incident parallel to the substrate as a reaction or decomposition light beam is provided. By controlling the intersection area of the heating beam and a second beam incident perpendicularly to the substrate, the photoinduced reaction of the gas phase reactant alone or the gas phase reactant and the oxygen-containing precursor can be performed. The resulting thin film is deposited on the substrate.

Here, the above gas phase reactants include silicon, poron, germanium, aluminum, phosphorus, gallium, indium, titanium, tungsten, halfnium, zinc, tantalum,
It is preferred to include molecules containing lead, barium, sodium, antimony or selenium.

Additionally, oxygen-containing precursors include nitrous oxide, nitrogen dioxide, -
It is preferable to use nitrogen liquefaction, -32 element oxide or oxygen molecules.

According to a preferred embodiment of the present invention, a photodissociation sensitizing vapor phase material is added to the atmosphere of the substrate, thereby increasing the rate of thin film deposition.

According to another preferred embodiment of the present invention, the beam shape and the irradiation position of the first and second light rays, or either one of these rays, are changed so that the intersection of these rays is changed. By changing the area, the position and shape of the thin film can be specified.

Furthermore, according to another preferred embodiment of the present invention, thin films having different compositions can be formed on the same substrate by sequentially changing the substances contained in the atmosphere of the substrate and their concentrations.

[Example] The present invention will be described in detail below with reference to the drawings.

FIGS. 1(A) and 1(B) are diagrams explaining the present invention in detail; FIG. 1(A) shows the substrate 1 viewed from above, and FIG. 1(B) shows the substrate 1 viewed from the side. Here is what it looks like,
The substrate 1 is placed in an atmosphere of a gas phase substance having a predetermined composition. Then, the light beam 2 for decomposition or reaction and the light beam for heating the substrate are made to enter the substrate and its vicinity,
As a result, a thin film 4 is formed on the substrate in the area where the two light beams 2 and 3 intersect. Thus, by controlling the intersection position of these two light beams 2 and 3, the formation position of the thin film 4 can be selected.

In addition, by sequentially changing the composition of the gas phase substance, the composition of the thin film formed will also change, so by controlling the intersecting position of these light beams and the composition of the gas phase substance, it is possible to Optical waveguides with different compositions can be formed in the same process while patterning the optical waveguides.

FIGS. 2(A) and 2(B) show an example of a reaction chamber for housing the substrate 1 described above. Here, Figure (A) shows a cross section of the reaction chamber, and Figure (B) shows a longitudinal cross section of the reaction chamber.

The sample substrate 1 is fixed on the sample holder 5 and is exposed to a gas phase substance supplied from the waste introduction port 6 and discharged from the suction lower. Then, through the light introduction window 8.1, light enters from a direction parallel to the substrate 1 for decomposition or reaction.
°The parallel light illuminates the vicinity of the substrate surface. At the same time,
Parallel light for "substrate heating" incident from vertically above the substrate irradiates the substrate 1. In this way, the substrate 1 is exposed to both light beams 2.
and 3 exposures.

Moreover, the supply amount control device 18 is a type of gas phase substance.

The composition such as concentration and flow rate are controlled, and the supply pipe 8.1~
1], n to the mixer 10. Then, the gas phase substance homogenized by the combiner 1O is supplied into the reaction chamber through the gas inlet 6.

Note that, since some silicon wafers have a diameter of up to 15 cm, it is preferable that the sample holding table 5 in the reaction chamber be sized so that it can be applied to such large substrates. The light introduction window 8.1 may be made of an ultraviolet light transmitting material such as subbrasil silica, calcium fluoride, or quartz, or a carbon dioxide laser transmitting material such as barium fluoride or zinc selenide, or other light beams to be used. Preferably, a compatible transparent material is used.

FIG. 3 illustrates the entire apparatus for carrying out the invention. Here, the sample substrate is placed in a reaction vessel [1]. and a 6-resolution or reaction beam device W113 controlled by a light beam controller 12 and a
°The light is emitted from the light flux device 14 for heating the substrate, and the light is emitted from the light introduction window 8.
．． The sample substrate is exposed to the light beam introduced via 1, 8.2.

As a luminous flux light source for decomposition or reaction, parallelization of the luminous flux is required, so F2, ArF,
In addition to gas excimer lasers using KrF, XeCl, N2, XeF, etc. (ultraviolet lasers that match ultraviolet absorption based on electronic transition), infrared lasers that match lattice vibration absorption of reaction gases, etc. are used.

°°When irradiating a wide area as a luminous flux light source for substrate heating, a powerful light source using an infrared lamp, a Xe lamp, a W lamp, etc. is used. Alternatively, when not only irradiating a wide area but also scanning the light beam, CO2, Ar, Ar'', He
A laser such as -Ne is used in accordance with the absorption wavelength of the substrate.

The method of controlling the shape to be exposed for the two types of light beams mentioned above and the method of controlling the irradiation position of these light beams need to be changed appropriately depending on the type of light source used. When using an infrared lamp, Xe lamp, W lamp, etc. as a luminous flux light source for "substrate heating".

In addition to irradiating the entire surface of the substrate, it is also used for decomposition or reaction.
The above-mentioned ultraviolet or infrared laser is used as the luminous flux light source.

Then, optical elements such as lenses, slits, pinholes, mirrors, and shutters are used to convert the beam shape, move the exposure position, and switch the beam on/off, thereby controlling the exposure shape and irradiation position of the two beams. do.

On the other hand, lasers with good parallelism are used for heating substrates.
'When used as a Koto light source, in addition to adopting the same control method as when using an infrared lamp, Xe lamp, W lamp, etc., the entire surface is irradiated with ultraviolet or infrared laser light from a direction parallel to the substrate. While performing the exposure, it is also possible to control the intensity distribution of the irradiation position 9 of the °' substrate heating °' light beam using an optical element similar to that described above.

Gas phase substances are supplied to supply devices 15.1, 15.2. ...15
．． n into the reaction vessel 11 via the supply amount control device 16. Here, the gas phase substances include gas phase reactants,
There is an oxygen-containing precursor, a sensitizer vapor, and a diluent gas.

and gas phase reactants include silane, disilane, silicon chloride, diporane, boron trichloride, germane, tetramethylgermane, trimethylaluminum, phosphine,
Trimethylgallium, trimethylindium, titanium tetrachloride, tungsten hexafluoride, halfnium hydride, trimethylzinc, etc. can be used. Also, oxidation-containing precursors include nitrous oxide, nitrogen dioxide, and butyride.

-S carbon, oxygen, etc. can be used. Furthermore, mercury dihydrogen or the like can be used as a sensitizer vapor to increase the deposition rate, and argon, nitrogen, hydrogen, helium or the like can be used as a diluent gas.

For gases with low filling pressure, such as -S-carbon, the necessary vapor pressure can be obtained by increasing the gas temperature. Furthermore, in the case of a gas such as trimethylaluminum which has a low vapor pressure at room temperature, the necessary vapor pressure can be obtained by heating it and using a carrier gas in combination. After that, the supply device 15
．． 1-15. Supply to the supply amount control device 18 is performed from n.

Unnecessary gas phase substances within the reaction vessel 11 are removed using an exhaust device 17.

4 through 6 each illustrate an optical waveguide formed according to an embodiment of the present invention. Each example will be described in detail below.

Example 1 Using quartz glass as a substrate, the entire surface of the substrate was irradiated with an infrared lamp and an ultraviolet laser (wavelength 183 nm)
was used as a light source for decomposition or reaction. Then, using a cylindrical lens and a slit with a width of 50 gm, the beam was moved laterally parallel to the substrate, as shown in FIG.

At this time, the reactants are silane (SiHa), germane (
GeH, , ), the oxygen-containing precursor is nitrous oxide, and the diluent gas is argon.
As shown on the right side of Figure 4, the eH4 concentration was 100% each.
The weight part was changed continuously from 80 parts by weight and from 0 parts by weight to 20 parts by weight, thereby obtaining a graded optical waveguide 51.

Example 2 A commercially available silicon wafer was used as a substrate, and the substrate was placed in an atmosphere in which a mixed gas of 5 parts by weight of silane and 100 parts by weight of -carbon oxide was diluted with helium. Then, a parallel beam with a diameter of 10 mm is obtained using an Ar laser and a lens system, and a long and narrow beam (see FIGS. 5(A) and (B)) is formed using a slit with a rough radiation of 10 ILm. was scanned.

At the same time, as shown in FIGS. 5(A) and (B),
An ultraviolet laser beam (wavelength: 1~33 nm) was incident parallel to the substrate and gradually separated into two beams of the same width, thereby obtaining a two-branch optical waveguide 61 shown in FIG.

Example 3 A crystal piece 71 having a side of 2 mm was used as a substrate.

Then, a square carbon dioxide laser beam with a width of 50 mm and a length of 50 lm is irradiated in two directions, and a layer with a width of 10 g
, by injecting an ultraviolet laser with a beam shape of 10#La+ in length from the y direction, and scanning by overlapping both beams in the x direction.

The hydrogen-diluted silane gas atmosphere is decomposed and the result is shown in Figure 6 (A
) A thin film of amorphous 5i-H with an area of 5 Qpm as shown in
Formed over X100 jL ffi.

Thereafter, an electrode forming mask is placed at a point 0.1 cm above the adhered part, and the entire surface of the substrate is irradiated with an ultraviolet laser beam from the y direction, and a carbon dioxide laser beam is irradiated from the z direction over the entire surface of the substrate to remove the trimethylaluminum atmosphere. Metal aluminum is decomposed and produced, resulting in Fig. 6 (B)
An electrode 73 shown in FIG.

Furthermore, after that, the entire surface was irradiated with an ultraviolet laser beam from the y direction, and a width of 50) Lm and a length of 100 g was applied.
An optical waveguide having an 80° bend as shown in FIG. Reactive deposition was carried out in a mixed atmosphere, thereby obtaining an element having an optical waveguide 74 and photodetecting sections 72 and 73 as one body.

[Effect] As explained above, according to the present invention, the desired film thickness, refractive index distribution, Since it is possible to form a leading waveguide having a specific shape and composition, it is possible to obtain a method for manufacturing a four-wavelength optical waveguide with improved productivity using a dry process. In particular, the present invention is suitable for integrating various optical elements on the same substrate within the same manufacturing apparatus. Furthermore, the present invention can also be applied to selective doping.

[Brief explanation of drawings]

Figures 1 (A) and (B) are schematic diagrams illustrating the principle of the present invention in which a film is formed by intersecting two types of light beams. Figures 2 (A) and (B) are reaction reactions that accommodate the substrate. 3 is a schematic configuration diagram illustrating the entire apparatus for carrying out the present invention; FIG. 4 is a conceptual diagram illustrating a method for forming a graded type leading waveguide and a refractive index distribution; Figures 5 (A) to (C) show the method 1 for forming a bifurcated optical waveguide.
・・Sample substrate, 2. Temperature lamp for decomposition or reaction, 3. Luminous flux for substrate heating, 4. Thin film deposition part, 5. Substrate support stand, 6. ... Gas inlet, I 7... Gas inlet. 8.1, 8.2... Light introduction window, 8.1-8.n... Gas supply pipe. 10... Gas mixer , 11... Reaction container, 12... Light beam control device, 13... Light flux device for PA decomposition or reaction, 14...
°°Light flux device for heating substrates, 15.1-15. n...
・Reaction, carrier, and dilution gas supply equipment. 16... Supply amount control device, 51... Graded optical waveguide, 81... Bifurcated optical waveguide, ? ! ...Crystal piece? 2... Amorphous 5i-H1 73... Aluminum electrode, 74... Curved optical waveguide. i 1fiJlt included Nippon Telegraph and Telephone Public Corporation Figure 1 Figure 2 (A)

Claims (1)

[Claims] l) A method for manufacturing an optical waveguide by forming a thin film on a substrate, comprising: a first light beam incident parallel to the substrate as a reaction or decomposition light beam; and a first light beam incident on the substrate as a heating light beam. By controlling the area of intersection with a second beam incident perpendicularly to the substrate, a thin film resulting from a photoinduced reaction of the gas phase reactant alone or with an oxygen-containing precursor is applied to the substrate. 1. A method for manufacturing an optical waveguide, characterized in that the optical waveguide is coated. 2) The gas phase reactant is silicon, poron, germanium,
The optical waveguide according to claim 1, characterized in that it contains molecules containing aluminum, phosphorus, gallium, indium, titanium, tungsten, halfnium, zinc, tantalum, lead, barium, sodium, antimony, or selenium. manufacturing method. 3) The # element-containing precursor is nitrous oxide, nitrogen dioxide,
The method for manufacturing an optical waveguide according to claim 1 or 2, characterized in that - nitrogen oxide, - carbon oxide, or oxygen molecules are used. 4) A method according to any one of claims 1 to 3, characterized in that a photodissociation reaction-sensitizing gas phase substance is added to the atmosphere of the substrate to increase the deposition rate of the thin film. A method for manufacturing an optical waveguide. 5) By changing the beam shape and the irradiation position of the first and second light beams or any one of these light beams with respect to the substrate, the intersecting area of these light beams is changed to change the deposition position of the thin film. , Claims 1 to 4 are characterized in that the shape is specified.
A method for manufacturing a guiding waveguide according to any one of paragraphs. 6) The method according to any one of claims 1 to 5, characterized in that thin films having different compositions are formed on the same substrate by sequentially changing the substances contained in the atmosphere of the substrate and their concentrations. A method for manufacturing an optical waveguide. (Hereafter, margin)