JPH06109936A - Optical waveguide fabrication method - Google Patents

Abstract

(57) [Abstract] [Purpose] To facilitate the processing of polysiloxane in the production of optical waveguides. [Structure] Polysiloxane repeating unit The polysiloxane A of the formula 3 and the 1: 5 copolymer polysiloxane B of the formulas 3 and 4 are formed on the substrate 1 by spin coating to form a spin coat film 2 serving as a lower clad layer and a core layer, which is 265 nm in air. UV light 4 near the mask 3 with a pattern
The film 2 is irradiated with light to etch it, and the film 2 is etched with an organic solvent (chlorobenzene) 5 to leave the solubility changing portion 2a and serve as a core.
An upper clad layer of polysiloxane A is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an optical waveguide, and more particularly to a method for producing an optical waveguide for an optical integrated circuit using polysiloxane.

[0002]

2. Description of the Related Art As a base material for optical parts and optical fibers, an inorganic material such as quartz glass or multi-component glass is generally used because of its small optical transmission loss and wide transmission band. On the other hand, an optical waveguide based on plastic has also been developed. These plastic optical waveguides are attracting attention because they have better workability by reactive ion etching (RIE) and the like than inorganic ones, and have features such as handling. Among such plastics, polysiloxane materials are excellent in heat resistance and light transmittance. However, this polysiloxane is generally known to have good RIE resistance, and it has been difficult to easily fabricate a patterned polysiloxane optical waveguide.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing an optical waveguide in which polysiloxane, which is difficult to process, can be easily processed. Is.

[0004]

That is, a method of manufacturing an optical waveguide according to the present invention is described in the following general formula (1) (Chemical formula 1) [wherein R ₁ and R ₂ are the same or different and C _n Y _{2n +} A deuterated or halogenated alkyl group represented by ₁ (Y represents deuterium or halogen, n represents a positive integer of 5 or less),
Or a deuterated or halogenated phenyl group represented by C ₆ Y ₆ (Y represents deuterium or halogen)
A halogen- and / or deuterium-containing polysiloxane having a repeating unit represented by the following general formula (2) (Chemical formula 2) [in the formula, R ₁ and R ₂ are the same or different, and C _n Y
_{2n + 1} (Y represents deuterium or halogen, n represents a positive integer of 5 or less) or a deuterated or halogenated alkyl group, or C ₆ Y ₆ (Y represents deuterium or halogen) A deuterated or halogenated phenyl group represented by the formula] and a polysiloxane containing halogen and / or deuterium having a repeating unit represented by the following general formulas (1) and (2) The desired portion of the polymer selected from the group consisting of a polysiloxane containing halogen and / or deuterium, which is a copolymer containing, and a mixture thereof is irradiated with light in the presence of oxygen to change the solubility in a solvent. A desired pattern is produced by utilizing this difference in solubility, and the pattern portion is used as a core or a clad of an optical waveguide.

[0005]

The principle of patterning used in the method for producing an optical waveguide of the present invention will be described.

First, the structural formula (repeating unit) of the material polysiloxane (I) used in the present invention is shown below.

[Chemical formula 1] [wherein R ₁ and R ₂ are the same or different, and C _n Y _{2n + 1} (Y is deuterium or halogen;
n represents a positive integer of 5 or less) or a deuterated or halogenated alkyl group represented by C ₆ Y ₆ (Y represents deuterium or halogen) and deuterated or halogenated phenyl. Represents a group. Similarly, the structural formula (repeating unit) of the material polysiloxane (II) used in the present invention is shown below. [Chemical Formula 2] [wherein R ₁ and R ₂ are the same or different and are represented by C _n Y _{2n + 1} (Y is deuterium or halogen, and n is a positive integer of 5 or less). Or halogenated alkyl group, or C ₆ Y ₆ (Y
Represents deuterium or halogen) and represents a deuterated or halogenated phenyl group. Further, as the material polysiloxane (III), a copolymer containing both the repeating units (I) and (II) can also be used.

Furthermore, the material polysiloxane (I),
Blends in which (II) and (III) are mixed in various ratios can also be used.

The polysiloxanes (I), (II) and (III) used in the method of the present invention are disclosed in Japanese Patent Application No. 1-1.
It can be manufactured by the method described in 78090.

The materials polysiloxanes (I), (II) and (III) used in the present invention all have R ₁ --Si-- and R ₂ --Si as bonds. These bonds are irradiated with UV light in an oxygen atmosphere, for example, in the air, cut by light energy to change the solubility property of the polymer, and patterned by the difference in solubility between the irradiated part and the unirradiated part. .

Regarding the patterning process in the optical waveguide manufacturing process according to the present invention, two methods are shown in FIGS. 1 and 2.

First, the method (a) shown in FIG. 1 will be described.

(A-1) Material A polysiloxane spin coat film 2 is formed on a substrate 1 using a solution in which polysiloxane is dissolved, and heated to remove the solvent (film forming step, FIG. 1A). ).

(A-2) Next, using the mask 3 having an arbitrary pattern drawn, UV light 4 having a wavelength of 300 nm or less is irradiated through the mask 3 in the presence of oxygen, for example, in air (exposure step, FIG. 1B).

(A-3) The polysiloxane spin coat film 2 on the exposed substrate 1 is etched by using an appropriate organic solvent 5 to leave the solubility changing portion 2a (developing step,
FIG. 1C).

Next, the method (b) shown in FIG. 2 will be described.

(B-1) Material A polysiloxane spin coat film 2 is formed on a substrate 1 using a solution in which polysiloxane is dissolved, and heated to remove the solvent (film forming step, FIG. 2A). ).

(B-2) Next, laser light (wavelength 300 n
a moving stage 7 on which the substrate 1 is placed while irradiating with excimer laser light (6 m or less) in the presence of oxygen, for example, in the air.
Is scanned by the moving stage controller 8 to draw an arbitrary pattern 2b on the film (exposure step, FIG. 2B).

(B-3) Substrate 1 irradiated with laser light 6
The above polysiloxane spin coat film 2 is etched using an appropriate organic solvent 5 to leave the solubility changing portion 2b (developing step, FIG. 2C).

[0020]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Example 1) Formula (3)

[0022]

[Chemical 3]

Equation (4)

[0024]

[Chemical 4]

Material A 10% chlorobenzene solution in which polysiloxane (A) which is polysiloxane (II) (a polymer having a repeating unit of the formula (4)) is dissolved is applied onto a silicon substrate by spin coating (rotation speed). :
1000 rpm). The obtained film was heated and dried at 110 ° C., and the solvent was sufficiently removed to form a lower clad layer.
After confirming that the film is completely dried, a polysiloxane (B), which is a material polysiloxane (III) having a higher refractive index than the polysiloxane (A), is further formed on this film.
A 8 μm thick film was deposited as a core layer using a chlorobenzene solution containing (a polymer having a repeating unit of the formula (3) and a 1: 5 copolymer of a polymer having a repeating unit of the formula (4)). Spin coater speed is 1
It was 000 rpm.

Next, a mask having a linear pattern with a width of 8 μm was prepared, and light having a wavelength of about 265 nm was irradiated through the mask in air. This film was developed with chlorobenzene. As a result, the polysiloxane (B) remains only in the UV light irradiation part, and the non-irradiation part elutes, and the width is 8 μm and the height is 8 μm.
The pattern of m remained as a ridge. After sufficiently heating and drying, polysiloxane (A) was applied onto this pattern to form an upper clad layer, and a buried type three-dimensional optical waveguide was manufactured.

The optical waveguide was irradiated with light having a wavelength of 1300 nm from one end, and the loss of the optical waveguide was measured by measuring the amount of light emitted from the other end. The loss of this optical waveguide was 0.1 dB / cm or less. Next, wavelength 1550n
When a similar experiment was performed using m light, the loss was 0.1 dB / cm or less even at this wavelength. Also,
When the near-field image of the emitted light was observed using a near-infrared camera, it was found that the mode was single mode in both wavelength regions of 1300 nm and 1550 nm.

Example 2 As in Example 1, polysiloxane (A) was used to deposit a lower clad layer, and polysiloxane (B) was used to deposit a film having a thickness of 8 μm as a core layer. This film was placed on an XY moving stage which was set to move in one direction by the control unit of the moving stage, and the stage was moved while irradiating the excimer laser light having a wavelength of 300 nm or less. As a result, the irradiated portion was a straight line having a width of 8 μm, and patterning was possible. The film was then treated with a developer. The unirradiated portion was eluted, and a pattern having a width of 8 μm and a height of 8 μm remained as a ridge.
Further, an upper clad layer was laminated in the same manner as in Example 1 to manufacture a buried type three-dimensional optical waveguide. When the loss was measured in the same manner as in Example 1, wavelengths of 1300 nm and 15
At 50 nm, the loss was 0.1 dB / cm or less. Further, the single mode was set in both wavelength regions of 1300 nm and 1550 nm.

In each of the above embodiments, only an example of manufacturing a linear three-dimensional optical waveguide has been described. In addition to this, a branching / merging circuit, a directional coupler, and a Mach-Zehnder circuit, which form the basic structure of the optical waveguide circuit, are also described. The ring circuit and the like could be easily manufactured by changing the mask pattern and adjusting the control unit of the XY moving stage.

[0030]

As described above, according to the method of manufacturing an optical waveguide of the present invention, it is possible to easily prepare a finely divided polysiloxane having excellent light transmission characteristics in the visible to near infrared light region, which has been difficult to process. Since it can be processed, there is an advantage that a high-quality optical integrated circuit with low loss and high reliability in the near infrared region can be easily supplied. That is, there is an advantage that an optical signal transmission system such as a local area network or the like, which is excellent in economic efficiency and has high reliability, can be configured by an optical component manufactured using an optical circuit using this manufacturing method.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating an example of patterning (method (a)) in the method for producing an optical waveguide of the present invention.
(A) shows a film forming process, (B) shows an exposure process, and (C) shows a developing process.

FIG. 2 is a schematic cross-sectional view illustrating an example of patterning (method (b)) in the method for producing an optical waveguide of the present invention.
(A) shows a film forming process, (B) shows an exposure process, and (C) shows a developing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Polysiloxane spin coat film 2a, 2b Solubility change part 3 Mask 4 UV light (wavelength 300nm or less) 5 Organic solvent 6 Laser light (wavelength 300nm or less) 7 Moving stage 8 Moving stage control part

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Saburo Imamura 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. The following general formula (1): [In the formula, R ₁ and R ₂ are the same or different, and C _n Y
_{2n + 1} (Y represents deuterium or halogen, n represents a positive integer of 5 or less) or a deuterated or halogenated alkyl group, or C ₆ Y ₆ (Y represents deuterium or halogen) A deuterated or halogenated phenyl group represented by the formula: and a polysiloxane containing halogen and / or deuterium having a repeating unit represented by the following general formula (2): [In the formula, R ₁ and R ₂ are the same or different, and C _n Y
_{2n + 1} (Y represents deuterium or halogen, n represents a positive integer of 5 or less) or a deuterated or halogenated alkyl group, or C ₆ Y ₆ (Y represents deuterium or halogen) A deuterated or halogenated phenyl group represented by the formula] and a polysiloxane containing halogen and / or deuterium having a repeating unit represented by the general formula (1) and (2) Irradiating a desired portion of a polymer selected from the group consisting of a combined halogen- and / or deuterium-containing polysiloxane and a mixture thereof in the presence of oxygen,
A method for producing an optical waveguide, characterized in that the solubility in a solvent is changed, a desired pattern is produced by utilizing this difference in solubility, and the pattern portion is used as a core or a clad of the optical waveguide.