JP2000180648A - Processing of optical waveguide element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion of a clad layer and a light shielding film made of metal, and to obtain the superior optical transmittivity by specifying a relative moving speed of a laser beam and a work piece, and the shape of laser beam to be applied to the work piece. SOLUTION: An organic polymer is applied and baked on a base 1 to form a buffer layer 2, and then an organic polymer of refractive index higher than that of the buffer layer 2 is applied and baked to form a core layer 3 (a). Then an organic polymer is coated and baked to form an overclad layer 5 (b). An optical waveguide is patterned with excimer laser, and an edge is tapered with an obtuse angle or worked into the elliptic or semicircular shape by changing the relative moving speed of the laser beam of the excimer laser to be irradiated and the base (c). A light shielding film 6 is formed on the same according to the necessity (d). Whereby the optical waveguide superior in the mode matching characteristic with the fiber and superior in the optical transmittivity can be worked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide device, and more particularly to an organic film optical waveguide and a method for processing the organic polymer film.

[0002]

2. Description of the Related Art Conventionally, optical waveguide devices have been often used in the fields of optical communication and optical information recording. The optical waveguide element mainly uses an inorganic material such as quartz glass or Ti-diffused LiNbO ₃ or an organic material such as polyimide, and is formed on a substrate such as quartz glass, Si, InP, or Al ₂ O ₃ .

[0003] A general method of manufacturing these optical waveguide elements will be described with reference to FIG. First, the substrate 101 shown above
A buffer layer 102 of SiO ₂ or the like is formed on the upper surface by a sputtering method (FIG. 13A).

Next, a thin-film or thick-film planar optical waveguide core layer 103 is formed on the entire surface of the substrate by sputtering, spin coating, spraying, or the like (FIG. 13).
(B)) Copper or aluminum is formed thereon as a metal mask 107 by sputtering or the like (FIG. 13).
(C)).

Further, a photoresist 108 of an organic material is applied thereon by spin coating and baked. Thereafter, the waveguide film is exposed and etched by a lithography technique using a photomask having a desired pattern to obtain a desired pattern (FIG. 13D).

Next, patterning is performed by dry etching with a gas to obtain a core of a patterned waveguide (FIG. 13).
(E)). An over clad layer 105 having a lower refractive index than the core is formed by spin coating or the like on the patterned waveguide core 103 formed as described above, and is baked to obtain a patterned optical waveguide (FIG. 13F). .
Further, although not shown. A light-shielding film for blocking external light is formed thereon.

On the basis of such a method of forming a waveguide, Japanese Patent Application Laid-Open No. 5-173036 discloses a method of forming a tapered waveguide. Here, first, a waveguide core is formed using an etching mask having a tapered shape in the width direction by the method of FIG. 13 described above, and then a viscous substance is applied thereon, and the thickness of the core layer is determined by etching the entire surface. Is tapered.

[0008] Further, in a method of manufacturing a waveguide disclosed in Japanese Patent Application Laid-Open No. Hei 5-210020, after a waveguide core pattern is formed by the above method, the light is condensed using a carbon dioxide gas laser and the waveguide is condensed. By partially melting the waveguide pattern without thermally damaging the substrate, a waveguide pattern having a circular cross section is obtained.

[0009]

In the above prior art,
There are the following problems.

[0010] Since the general waveguide processing uses dry etching such as photolithography and RIE,
In the process, only a rectangular cross section is obtained, and a complicated process is required to obtain a waveguide having a circular cross section.

In Japanese Patent Application Laid-Open No. 5-173036, the width of the waveguide and the viscosity of the material must be controlled in order to obtain a tapered shape. Since the taper angle is uniquely determined by the viscosity of the material, the degree of freedom in design is small. In addition, since the waveguide shape is rectangular, mode matching with a fiber having a circular cross section cannot be obtained, and the light propagation characteristics deteriorate.

In Japanese Patent Application Laid-Open No. Hei 5-210020, since a waveguide is melt-processed by a thermal process using a laser such as CO ₂ , the waveguide is naturally damaged, and the substrate and the cladding are not only damaged together with the waveguide pattern. The layers are distorted. In addition, the waveguide is partially melted, rounded by its surface tension, and a waveguide having a curved cross section is obtained. However, dimensional accuracy cannot be obtained, and it is not easy to obtain a waveguide as designed. . In the case of hot melt processing such as CO ₂ , local heat is easily distorted, and a stable waveguide cannot be obtained. This is not satisfied, and as a result, a waveguide having a good circular cross section cannot be obtained.

Further, when the waveguide has a rectangular cross section, a light-shielding film is hardly formed particularly on an edge portion having an acute angle. It penetrates into the waveguide and leads to a decrease in the SN ratio.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to eliminate edges in the cross-sectional shape of an organic polymer waveguide pattern so that the edge angle without thermal damage is obtuse. By obtaining a certain waveguide pattern or a circular waveguide pattern, the adhesion between the cladding layer and the metal light-shielding film can be improved, good light propagation characteristics can be obtained, and mode matching with the fiber can be improved. It is an object of the present invention to provide a method for processing an optical waveguide element, and to provide a method for processing an optical waveguide element having a three-dimensional shape that can be favorably connected to a fiber.

[0015]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. According to the first aspect of the present invention, a core layer formed on a substrate is irradiated with a laser beam. A method of processing an optical waveguide element for processing into an optical waveguide pattern, wherein the relative movement speed between a laser beam and a workpiece, and the shape of a laser beam to be irradiated on the workpiece are specified, whereby the workpiece is processed. A method of processing an optical waveguide element, comprising processing a core layer formed on a substrate into a desired optical waveguide pattern.

The invention according to claim 2 is the method for processing an optical waveguide device according to claim 1, wherein the relative speed is constant and the laser beam shape is rectangular.

According to a third aspect of the present invention, in the method of the first aspect, the relative speed is constant and at least one side of the laser beam is curved. It is.

The invention according to claim 4 is the method for processing an optical waveguide device according to claim 1, wherein the relative speed is changed and the laser beam is formed in a rectangular shape.

According to a fifth aspect of the present invention, the area of the irradiation area of the laser beam is set to be equal to or larger than the planar projection area of the processing area of the workpiece. This is a method for processing the optical waveguide device.

The invention according to claim 6 is the method for processing an optical waveguide device according to any one of claims 1 to 5, wherein the laser is an excimer laser.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an optical waveguide according to the present invention and a method of forming the same will be described below with reference to the drawings.

FIGS. 1A to 1C are schematic views showing a cross section of an optical waveguide according to the present invention. 1A and 1B, an organic polymer having a lower refractive index than the core layer 3 is formed on the substrate 1 as the buffer layer 2. A core layer 3 made of a polygonal, elliptical, or substantially circular organic polymer is formed thereon. If necessary, an over cladding layer 5 is formed on the core layer 3, and a material having a lower refractive index than the core layer 3 is selected.

For example, an organic film such as polyimide can be used for the buffer layer 2 and the over cladding layer 5. In the case of an organic film, it is formed by a spin coating method, and has a configuration in which the periphery of the over cladding layer 5 is covered with a light shielding film 6 made of a metal such as aluminum having a thickness of about 100 nm.

Next, a creation method will be described with reference to FIG.

1) First, an organic polymer is applied as a buffer layer 2 on a substrate 1 by spin coating and baked, and then an organic polymer having a higher refractive index than the buffer layer 2 is applied and baked as a core layer 3. (FIG. 2A).

2) Further, an organic polymer is applied and baked as the over cladding layer 5 (FIG. 2B).

3) Next, by patterning the optical waveguide with an excimer laser and changing the relative movement speed between the laser beam of the excimer laser to be irradiated and the substrate, the edge is tapered at an obtuse angle, or an ellipse or a substantially semicircle (FIG. 2C).

4) If necessary, a light shielding film 6 is formed thereon (FIG. 2D).

FIG. 1 (c) is the same as FIG. 1 (a),
Unlike (b), an inorganic dielectric film such as silicon oxide is used as the buffer layer 2. CV for inorganic dielectric film
It is formed by a D method, a sputtering method, an evaporation method, or the like.

The steps relating to the above-mentioned preparation will be described with reference to FIG.

1) First, silicon oxide is formed as a buffer layer 2 on a substrate 1 by a CVD method (FIG. 3).
(A)).

2) Further, as the core layer 3, an organic polymer having a higher refractive index than that of the buffer layer 2 is applied by spin coating and baked (FIG. 3B).

3) A copper or aluminum film is formed thereon as a metal mask 7 by sputtering or the like (FIG. 3).
(C)).

4) Next, a photoresist 8 is applied and patterned by a photolithography process (FIG. 3).
(D)).

5) Next, the mask pattern is transferred to the metal mask 7 by ion milling or wet etching (FIG. 3E).

6) Next, the core layer 3 is etched by RIE using oxygen gas (FIG. 3 (f)).

7) Thereafter, the metal mask 7 is removed by wet etching (FIG. 3G).

8) Next, the waveguide having an acute edge is tapered at an obtuse angle or processed into an elliptical or substantially semicircular curved surface by an excimer laser (FIG. 3 (h)).

9) As the over cladding layer 5, an organic polymer having a lower refractive index than the core layer 3 is applied by spin coating and baked (FIG. 3 (i)).

10) If necessary, a metal light shielding film 6 is formed thereon (FIG. 3 (j)).

2 and 3, a waveguide having a polygonal, elliptical, or substantially semicircular cross section can be obtained.
In the above manufacturing method, the possibility of processing is determined by the material of the buffer layer 2 or the over cladding layer 5 and the power of the excimer laser. For this reason, various modifications can be given, but only representative ones are described here.

In such an organic optical waveguide device, the cross section of the waveguide is polygonal, elliptical, or substantially semicircular, so that the core layer 3 and the over cladding layer 5 or the over cladding layer 5 and the light shielding film 6 are formed. Good adhesion. Further, as compared with an optical waveguide having a rectangular cross section, mode matching with an optical fiber having a circular cross section is better, and the SN ratio is improved.

The manufacturing process here is merely an example, and the organic polymer may be processed by a processing method other than RIE, or a partially modified process may be used.

As the organic polymer material, a material having a high transmittance is desirable, and when integration with a semiconductor laser is considered, a heat treatment for forming an ohmic electrode is required.
Heat resistance of 00 ° C. or higher is required. For this reason, it is desirable to use polyimide having high heat resistance and relatively high transmittance as the core material among the organic polymers. Furthermore, by using fluorinated polyimide, the transmittance in the visible light region is further increased, and a low-loss organic optical waveguide particularly suitable for communication applications can be obtained.

Next, as shown in FIGS. 2 (c) and 3 (h), a method of processing the edge of the optical waveguide formed of an organic polymer film of polyimide with an excimer laser on the end face of the optical waveguide will be described in detail. I do.

FIG. 4A is a diagram for explaining the relationship between the processing conditions and the processing depth. Let the oscillation frequency of the excimer laser be f
(Hz), irradiation time of excimer laser is t (s), processing depth r (mm) per pulse of excimer laser beam
Then, the processing depth d (mm) is

[0047]

(Equation 1)

Is as follows.

When the moving speed of the stage is constant, the length of the excimer laser beam on the work in the scanning direction is L
(Mm), the relative movement speed of the stage with respect to the beam is represented by v
(Mm / sec), the irradiation time t is represented by t = L / v, and the processing depth d1 (mm) is

[0050]

(Equation 2)

Is as follows.

In FIG. 4A, since the shape of the laser beam 10 for scanning the workpiece is rectangular, the cross-sectional shape of the groove to be processed is rectangular (the final irradiation surface has a different irradiation time and has a tapered shape). However, when the laser beam is formed into a triangular shape as shown in FIG. 4B, tapering can be performed, and when the elliptical beam is scanned as shown in FIG. The cross-sectional shape of the processed groove is also determined by the shape. That is, the processed cross-sectional shape is determined by the amount of energy applied per unit time. In the case of obtaining an elliptical curvature in the cross section, FIG.
It can be understood that a beam shape having one or more sides having a curvature as described above may be used.

As another processing method, the processing section just below the rectangular mask shown in FIG. 4E is a curved surface. That is, even if the mask shape is rectangular, if the moving speed v of the mask or the stage is changed (the stage is moved with acceleration), the irradiation energy amount can be changed, and as a result, the processing of a curved cross section becomes possible.

The processing depth when the stage is moved with acceleration will be described with reference to FIG. In the figure, reference numeral 15 denotes a laser beam irradiation area. Reference numeral 15a denotes an irradiation area at a laser irradiation initial position, 15b denotes an irradiation area at a processing start position, and 15c denotes an irradiation area at a final irradiation position.

Considering the processing depth of the minute length ΔL by laser irradiation, and letting the laser irradiation time be Δt, the processing depth Δd
Is

[0056]

(Equation 3)

Is as follows.

As described above, in order to know the processing amount, the laser irradiation time at the processing position may be obtained.

Here, the distance from the laser irradiation initial position to the processing position is L1, and the time t1 from the laser irradiation initial position to the processing start position at the processing position L1 is determined by using the stage moving speed v (t). Can be obtained by the following equation. Here, L1, v (t) is determined by design,
Assume that it is already known.

[0060]

(Equation 4)

Next, the irradiation time depending on the processing position will be considered.
Assuming that the laser irradiation distance by the mask is L, the irradiation time immediately below the final irradiation surface is shortened and a taper is formed. Here, assuming that the distance from the laser irradiation initial position to the laser irradiation final position is L1max, the processing amount can be considered in the following cases.

In the case of L1 ≦ L1max−L The laser irradiation time at the processing position L1 is the passage end time t2.
Then, the distance to the laser irradiation completion position is L1 + L
Therefore, the following equation is established, and t2 is obtained.

[0063]

(Equation 5)

Therefore, the total processing depth d2 at a position L1 away from the beam initial position is equal to the passing time (t
2-t1) Since it is irradiated, the processing depth d2 (mm) is

[0065]

(Equation 6)

## EQU10 ##

On the other hand, in the case of L1> L1max-L, the following formula is satisfied when the laser irradiation time at the processing position L1 is t2max, where t2max is the final arrival time of the laser.

[0068]

(Equation 7)

Accordingly, since the entire processing depth d2 at a position L1 away from the beam initial position is irradiated during the laser irradiation passage time (t2max-t1), the processing depth d2 is obtained.
(Mm) is from Equation 3.

[0070]

(Equation 8)

## EQU5 ##

From the above results, when the stage moving speed is constant, the final irradiation surface shape is a tapered shape having a certain angle, and when the stage movement is accelerated, the final irradiation surface shape is a curved surface shape. I understand.

In general, optical components are required to have a high-precision machined surface roughness. Excimer lasers are pulsed lasers. When a laser beam is irradiated while moving the beam or the object to be processed, the processing proceeds as the laser irradiation position moves for each pulse, so that minute irregularities are formed on the processing surface. Is done. In the processing of a polymer material using an excimer laser, an ideal material is decomposed and removed by a photochemical reaction, so that the irregularities are equal to the processing amount per laser pulse. That is, in order to reduce the roughness of the processing surface, the processing amount per pulse may be reduced. It is generally known that the amount of processing can be reduced by adjusting the energy of the laser beam.

For an optical component requiring a clean processing surface,
The surface roughness of the processed surface needs to be sufficiently small with respect to the wavelength of the target light.
It has been confirmed that when a semiconductor laser having a thickness of 10 nm is used, the maximum surface roughness of the processed surface is 1/10 of the wavelength, that is, 78 nm or less, so that predetermined optical characteristics are satisfied. Therefore, a desired shape can be obtained by adjusting the amount of energy of the excimer laser applied to the processing area so that the processing depth per pulse by the excimer laser processing is 78 nm or less.

Next, FIG. 6 shows a schematic configuration diagram of the excimer laser excitation device 20 used for the end face processing. This device is manufactured by Sumitomo Heavy Industries, Ltd., the gas used is KrF, the laser oscillation wavelength is 248 nm, and the oscillation output is 27
0 mJ, the oscillation frequency is 200 pulses per second.

In FIG. 6, the excimer laser oscillator 21
First, the laser light emitted from passes through the variable attenuator 22. The variable attenuator 22 includes:
The transmittance of the excimer laser light can be adjusted in a stepless manner, and the energy of the light applied to the substrate 1 on which the workpiece is mounted is adjusted by changing the transmittance of the laser light.

Next, the laser beam path is determined by the beam bender 23. A laser mask 24 is set in the laser beam path,
The laser beam is shaped into a required shape. Further, the reduction rate of the laser beam area is 1/10 to 1/36.
An image of the mask pattern 24 is reduced and projected onto the substrate 1 by a reduction optical system such as a quartz lens, which can be arbitrarily set, and adjusted so that the beam power on the substrate 1 becomes 60 mJ / cm ^2. .

Here, the mask pattern was reduced to 1/10 and projected onto the substrate. As a condition of the excimer laser to be irradiated, a processing depth per pulse was measured in advance under the conditions of the laser, and was found to be 0.03 (μm / P
ulse).

Through the above optical system, the laser beam 10 is irradiated on the end face of the optical waveguide of the workpiece. The stage on which the substrate is placed has a configuration in which the speed can be controlled in two directions (X and Y directions) and a height direction (Z direction) so that the stage can be moved.

FIG. 7 is a schematic view showing a process of tapering the end face of the workpiece by using an excimer laser. FIG.
7A is a diagram before processing, and FIGS. 7B to 7D are diagrams illustrating a progress step of the processing, and are diagrams after the processing in FIG. 7E is completed.

Here, a tapered surface can be obtained by irradiating the laser beam and relatively moving the workpiece. The tapered surface can be obtained by keeping the relative moving speed constant, and a curved surface shape can be obtained by changing the relative moving speed. Detailed experimental results will be described later. By applying the above-described processing to at least a portion including the waveguide core layer, the cross-sectional shape shown in FIGS. 1A to 1C becomes a trapezoidal (polygonal) shape or a circular shape. An optical waveguide element can be obtained.

The process shown in FIG. 7, that is, a method of forming an inclined end face on the edge end face portion will be described below with reference to FIG.

As shown in FIG. 7A, the laser mask 24,
The laser beam 10 that has passed through the reflection mirror 23 and the imaging lens 25 is focused on the workpiece, and irradiation with the laser beam 10 is started. At this time, the workpiece is not irradiated.

As shown in FIGS. 7B to 7E, the stage is moved at a constant speed while irradiating the laser beam 10. When the processing end position is reached, the laser beam irradiation is stopped. The stage 26 is stopped.

As a method of fabricating the optical waveguide device, highly transparent polyimide (OPI series N20 manufactured by Hitachi Chemical Co., Ltd.) is used as an organic insulating film of SiO ₂ as a buffer layer 2 on a quartz substrate 1.
05) by photolithography and RIE, t = 50 μm,
An organic insulating film formed by excimer laser using the mask shape, moving direction, irradiation area, and the like as parameters by the above-described method by forming the mask so as to have a width w = 400 μm and a length 1 = 2000 μm, and to form an inclination at about 90 ° edge Was processed. Thereafter, an over clad 5 and a light shielding film 6 were provided.

The laser mask hole shape used for the excimer laser processing, that is, the laser beam shape is rectangular or triangular (including a curved shape), and the laser beam shape is rectangular as shown in FIG. Length L
(Length in the moving direction) and width W were used. For a beam having a triangular shape, the width (base) W and the height L were set as shown in FIG. 8B.

FIG. 9 is a perspective view showing a beam position and a processed shape of the workpiece before (left in the figure) and after processing (right in the figure) the workpiece. 9A shows a case where the laser beam shape is a rectangle, FIG. 9B shows a case where the laser beam shape is a triangle, and FIG. 9C shows a case where the laser beam shape is a curved triangle. FIG. 9D shows a case where the laser beam shape is a curved semi-triangular shape, and FIG. 9E shows a case where the laser beam shape is rectangular.

FIG. 9 shows only the processed shape on one side. Table 1 shows the conditions and the results of the surface roughness measurement.

[0089]

[Table 1]

Example 1 (FIG. 9A) and Example 2
In FIG. 9B, an optical waveguide having a tapered edge shape can be obtained. In the third embodiment (FIG. 9C) to the fifth embodiment (FIG. 9E), a light guide having a curved surface shape can be obtained. A waveguide can be obtained, and both edges can be eliminated in the cross section of the optical waveguide.

The optical waveguide prepared as in the above embodiment was compared with an optical waveguide obtained by conventional RIE etching. As a result, the optical waveguide obtained by the RIE etching has a rectangular waveguide cross section, and the end face is formed almost vertical. It was difficult to form a metal light-shielding film on such a vertical end face by a CVD method, a sputtering method, or the like, and light shielding at a sharp edge portion was incomplete. Therefore, by eliminating the edge in the waveguide section as in the above embodiment, the CVD
Adhesion with the light-shielding film formed on the core and the cladding layer is improved by the method or the sputtering method, so that it is possible to eliminate the leakage light and prevent the incidence of external light.

Further, according to the third to fifth embodiments, the cross section can be processed into an elliptical shape and a circular shape, and good mode matching with the optical fiber can be obtained.

FIG. 10 shows a calculation result in the fifth embodiment performed by changing the relative speed between the substrate and the laser beam. The horizontal axis in FIG. 10 indicates the distance from the end face of the workpiece, and the vertical axis indicates the height from the bottom face of the workpiece.

The processing conditions at this time were as follows: stage initial speed v0 at the processing initial position v0 = 0.1 mm / min, pulse number 500 pulse / s, L = 190 μm, L1 = 25
0 μm, L1max = 340 μm, r = 0.03 μm /
pulse and the processing speed v = v0 × t3. The stage speed was kept constant at v = v0 until reaching the processing area.

From the above results, a curved surface shape can be obtained by appropriately changing the relative speed between the substrate and the laser beam. Processing is actually performed under the above conditions, and a surface profile measurement device (F
When the surface shape was measured by ormTalysurf Series2 [Taylor-Hobson Ltd.]), the processed shape was the same as the above calculation result.

When the irradiation area of the laser beam is set to be equal to or larger than the plane projection area of the core layer 3 as in the first and fifth embodiments, the moving time of the setting stage is shortened and the processing time is shortened. In addition, microscopic observation of the processed surface showed that there was little adhesion of the reaction product and that the processed surface had good surface roughness. This is because if the stage is moved toward the processing surface and is used as the final irradiation surface of the beam, the surface roughness is reduced, and a still better processing surface can be obtained.

The reason why the reaction product adheres is considered to be as follows.

[0098] Since the decomposed pieces that have been processed and ascended are further decomposed by the beam into secondary decomposition and further tertiary decomposition, finally, they react with oxygen in the air to form carbon dioxide gas. Therefore,
When the beam is irradiated, it is difficult to become a reaction product, and the adhesion of the reaction product to the processed surface is suppressed.

However, when the beam is moved during the processing, the processing surface itself moves, so that the beam is not irradiated on the processed surface after the processing is completed, and the reaction products on the next processed surface are not surrounded. It splatters and re-adheres. Those in the beam traveling direction are again decomposed by the irradiation of the beam, so that the reattached reaction products are re-decomposed.

For the above reasons, in the taper processing using a laser, the processing end surface is obtained as the surface on which the reaction products are least adhered.

Next, an example in which the waveguide end face processing method using the excimer laser is applied to a three-dimensional waveguide will be described with reference to the drawings.

FIG. 11 shows this three-dimensional waveguide. The three-dimensional waveguide shown here is tapered not only in the width direction but also in the thickness direction along the light guiding direction on the substrate, so that the chip or the optical fiber between the elements or LD or PD, etc. The optical connection with the device can be performed with extremely high efficiency.

The fabrication method is a fabrication method using the above-described optical waveguide processing method by excimer laser ablation processing. The mask shape used here was a rectangular shape shown in FIG. 8A, and the processing of the three-dimensional waveguide was realized by moving the mask in the direction of the arrow in FIG. 11 while irradiating the laser beam. .

A method of realizing an arbitrary three-dimensional waveguide having a curvature at an edge will be described with reference to FIG. FIG.
Then, as shown in FIG. 12, by processing the end faces of the waveguides on both sides on a curved surface, a three-dimensional waveguide is obtained.

Therefore, an optical waveguide having an arbitrary taper can be obtained by changing the relative movement speed of the beam or the substrate in FIG. 11, and the relative movement speed of the beam or the substrate during the processing in FIG. By changing, an optical waveguide having an arbitrary curvature can be processed, and an arbitrary three-dimensional optical waveguide can be obtained. By using such an optical waveguide element having no edge on the end face in combination with a fiber, it is possible to prevent light scattering particularly due to the edge of the end face, to have good light propagation characteristics, and to have an optical condensing ability. Can be provided.

In the above description, the over cladding layer and the light shielding layer are provided on the core layer. However, such a core layer and the light shielding layer are not always required.

[0107]

According to the present invention, according to the method for processing an optical waveguide device according to any one of claims 1 to 4, it is possible to process an optical waveguide having good mode matching characteristics with a fiber and excellent light propagation characteristics. It is possible.

According to the method of processing an optical waveguide device according to the fifth aspect, the processing time is shortened, the adhesion of reaction products is further reduced, and the surface roughness of the processed surface is reduced, which is even more favorable. A machined surface can be obtained.

Further, according to the method for processing an optical waveguide element according to the sixth aspect, it is possible to perform processing by a non-thermal process, and it is possible to perform processing in which a pattern is not melted during processing and a residue is hardly formed. is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical waveguide device of the present invention.

FIG. 2 is an explanatory view of a method for processing an optical waveguide element according to the present invention.

FIG. 3 is an explanatory view of another processing method of the optical waveguide device of the present invention.

FIG. 4A is a diagram illustrating a relationship between processing conditions and a processing depth, and FIGS. 4B to 4E are schematic diagrams illustrating a laser beam shape and a processing shape at an irradiation position.

FIG. 5 is a schematic diagram for calculating a processing shape related to the processing method of the present invention and a diagram showing definitions of symbols.

FIG. 6 is a schematic configuration diagram of a laser excitation device used.

FIG. 7 is a schematic view of a step of performing taper processing on an end face of a workpiece by an excimer laser.

FIG. 8 is a schematic diagram showing a beam shape used for laser processing.

FIG. 9 is a diagram illustrating various laser beam shapes and processing shapes.

FIG. 10 is a diagram showing calculation results when the relative speed between the substrate and the laser beam is changed.

FIG. 11 is a diagram illustrating a processing step of a three-dimensional waveguide.

FIG. 12 is a diagram showing another three-dimensional waveguide processing step.

FIG. 13 is a view showing a conventional waveguide processing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Buffer layer 3 Core layer 5 Over clad layer 6 Shielding film 7 Metal mask 8 Photoresist 9 Workpiece 10 Excimer laser beam 15 Laser beam irradiation area 16 Processing area 20 Excimer laser excitation device 21 Excimer laser oscillator 22 Variable attenuator 23 Beam bender (reflection mirror) 24 Laser mask 25 Imaging lens 26 XY table (stage) 28 Controller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Noriaki Okada 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Hideaki Fujita 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F term (reference) 2H047 KA04 LA24 MA05 PA02 PA24 QA05 TA42 TA44

Claims (6)

[Claims] 1. A method for processing an optical waveguide element for processing a core layer formed on a substrate into a desired optical waveguide pattern by irradiating a laser beam, comprising: a relative moving speed between a laser beam and a workpiece; A method of processing an optical waveguide device, comprising: processing a core layer formed on a substrate, which is a workpiece, into a desired optical waveguide pattern by specifying a shape of a laser beam to be irradiated on the workpiece. 2. The method according to claim 1, wherein the relative speed is constant and the laser beam has a rectangular shape. 3. The method according to claim 1, wherein the relative speed is constant, and at least one side of the laser beam is curved. 4. The method according to claim 1, wherein the relative speed is changed and the laser beam is formed in a rectangular shape. 5. The method for processing an optical waveguide device according to claim 2, wherein an irradiation area of the laser beam is set to be equal to or larger than a planar projection area of a processing area of the processing object. 6. The method according to claim 1, wherein the laser is an excimer laser.