JP2001201646A - Die for optical device, master die for optical device, and manufacturing method of optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in productivity and cost caused by the request for the submicron optical axis adjustment accuracy when connecting an optical waveguide and an optical fiber and to solve such a problem that it is difficult to obtain a die for collectively forming an optical waveguide pattern and an optical fiber guide as the measure to solve the above mentioned problems. SOLUTION: A master die is manufactured firstly and a forming die is obtained by forming crystallized glass by using this. The optical device of the same shape as the master die is produced by forming by using the obtained forming die.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die for producing an optical component mainly used for optical communication by a molding method.
The present invention relates to a master mold for producing a molding die and a method for producing an optical element.

[0002]

2. Description of the Related Art In recent years, optical communication has been remarkably developed, and has come into practical use in CATV and computer networks. However, for widespread use such as FTTH, there is a demand for solution of problems such as significant cost reduction, mass production and miniaturization as optical components.

For example, an optical mounting circuit board using an optical waveguide has been proposed for integration and miniaturization of an optical transceiver. In this method, a silica-based optical waveguide having a desired function is formed on a silicon substrate, and further, a semiconductor element and an electric circuit are mounted by wiring metal electrodes, and optical fibers are arranged in an array by a V-groove guide. An optical module is formed by connecting the optical module to the optical waveguide (for example, Japanese Patent Application Laid-Open No. Hei 5-60940 or Japanese Patent Laid-Open No. 5-27-27).
No. 410 publication).

[0004] By using an optical waveguide in this manner, an integrated and miniaturized optical module can be realized.

[0005] However, these optical modules have a problem in terms of cost.

One is that optical waveguides are expensive. Optical waveguides are manufactured using semiconductor processes such as flame deposition, film formation by CVD, core patterning by photolithography and dry etching. However, since the chip size is relatively large, the cost reduction effect can be achieved even in mass production. Can't expect.

[0007] Another problem is that the connection cost between the optical waveguide and the optical fiber is high. As shown in FIG. 7, the substrate on which the optical waveguide is formed and the substrate on which the guide groove for fixing the optical fiber is formed are individually and separately separated.

In FIG. 7, reference numeral 71 denotes a silicon substrate, 72 denotes an optical waveguide, 73 denotes an optical fiber, 74 denotes a V-groove block, 75 denotes a laser diode, 76 denotes a photodiode, and 77 denotes an electric circuit pattern.

In order to suppress the optical loss between the optical fiber and the optical waveguide, it is necessary to adjust, assemble, and fix the position of ± 1 μm or less in the case of the single mode. These optical axis adjustments are currently performed with a system provided with an automatic adjustment mechanism for a number of axes, and have had great problems in terms of mass productivity and economy. Also, the V-groove is manufactured by selective wet etching of a silicon substrate or a grinding method of various substrates, and has disadvantages of poor mass productivity and poor groove shape reproducibility.

As a method for solving this problem, a groove for fixing the fiber and a groove corresponding to the core of the optical waveguide are formed by using press molding which has already been put into practical use as a method for manufacturing an aspherical glass lens, and the groove corresponding to the core is formed. A method of forming an optical waveguide by embedding a core material such as a resin in a groove is disclosed in
It is proposed in, for example, Japanese Patent No. 7141. In this method, for example, a mold having concave and convex shapes corresponding to a fiber fixing portion and an optical waveguide portion as shown in FIG. 8 is pressed against a workpiece to transfer an inverted shape thereof. Grooves can be mass-produced with good shape reproducibility.
Here, reference numeral 81 denotes an optical fiber guide groove forming portion;
Denotes an optical waveguide pattern forming part.

By embedding a core material such as a resin in the groove for the optical waveguide, the groove can be made to function as an optical waveguide. It is possible to easily optically connect the optical fiber and the optical waveguide with high efficiency without special position adjustment simply by disposing the optical fiber in the groove.

[0012]

When transferring an optical waveguide having a fine structure by press molding, there is a problem in obtaining a mold.

In the case of a single mode optical waveguide, it is difficult to machine it with high precision by machining because its cross section has a rectangular shape with a width and depth of about several microns. Hitherto, it has been proposed to form an optical waveguide pattern in a mold using dry etching (for example, Japanese Patent Application Laid-Open No. 11-21).
8631).

[0014] However, dry etching is excellent in processing accuracy of a minute shape, but it is difficult to process a shape having a size of tens to hundreds of microns, and it is difficult to process a shape having a large size difference. Also, the production efficiency of the mold is not high due to heavy use of photolithography and vacuum processes.
To that extent, the manufacturing cost of optical components increases.

On the other hand, if the optical waveguide pattern is processed by wet etching, an undercut (a phenomenon in which the lower portion of the mask is shaved and thinned) occurs, so that a rectangular cross section required for the optical waveguide cannot be obtained.

In a single mode optical fiber, the diameter is 12
It is about 5 microns, and the dimensional difference from an optical waveguide of about several microns is 10 times or more. For this reason, there is a problem that it is difficult to fabricate a mold having the above-described fiber fixing portion and a portion corresponding to the core of the optical waveguide simultaneously only by dry etching.

As described above, for example, it is necessary to use different processing methods such as machining of the optical fiber fixing portion and dry etching of the optical waveguide forming portion. However, when performing such different processing methods, when the optical waveguide and the optical fiber are in a single mode, the connection accuracy is ± 1.
Since it is less than μm, there is a problem that the mold processing becomes extremely severe in order to secure the accuracy, the mold becomes expensive, and mass production is impossible.

[0018]

In order to achieve the above object, a mold for an optical element according to the present invention comprises an optical waveguide pattern having a concave or convex shape and a light provided with a predetermined relative positional accuracy to the optical waveguide pattern. The mold for forming the fiber guide is a mold having crystallized glass on the press surface.

Crystallized glass can be finely processed by dry etching, and has several times higher mechanical strength than conventional mold materials such as quartz glass. Therefore, it is possible to realize a mold having good durability. Further, when molding glass or the like, if necessary, if a protective film made of a specific material and an intermediate layer are provided on the pressed surface, a mold having good durability can be obtained. Particularly, in the case of a single mode optical fiber or optical waveguide, the depth and width of the optical waveguide pattern are 15 μm or less, and the relative positional accuracy between the optical fiber guide and the optical waveguide pattern is ±
Although a thickness of 1 μm or less is required, these fine shapes can be formed without being damaged.

Further, in the method of manufacturing a molding die for an optical element according to the present invention, a master die having substantially the same shape as the final product is used, whereby the mother glass is heated and softened, and then the molded glass is subjected to high-temperature annealing. To form a mold. According to this, the mold itself can be manufactured by molding, and productivity and cost can be significantly reduced as compared with the conventional dry etching. Here, the mother glass means glass containing a nucleating agent, which has not been annealed for crystallization.

According to the present method, a master-shaped optical element is obtained. Therefore, if a master mold is obtained, a desired optical element can be manufactured even if the mold shape for molding an optical component is complicated and difficult to manufacture. For example, a mold for molding an optical element having an optical waveguide and a fiber fixing portion has a complicated shape and high accuracy, and it is difficult to directly produce this by dry etching or machining. It is available using the master mold manufacturing method of the present invention as described. In addition, the mold itself can be mass-produced using the master mold, and the cost of the mold and the cost of the optical element molded thereby can be significantly reduced.

The master mold for an optical element of the present invention is a master mold for molding a mold having a concave or convex optical waveguide pattern and an optical fiber guide molding portion, and the pressed surface is crystallized glass or quartz glass. , Diamond, DLC, sapphire, silicon or nickel. With the above configuration, a master mold for an optical element having a complicated shape can be realized because it has heat resistance and strength as a mold and is capable of fine processing and machining on the surface. Further, when molding glass or the like, if necessary, if a protective film made of a specific material and an intermediate layer are provided on the pressed surface, a master mold for an optical element having excellent durability can be obtained.

Further, as a first method for manufacturing a master for an optical element, an optical fiber guide portion is formed on a first member by grinding, and a second member is provided on a part of the first member. The second member is polished to a predetermined thickness, and an optical waveguide pattern is formed on the second member by photolithography and etching.

In a second method for manufacturing a master for an optical element, an optical fiber guide is formed on a mold member by grinding, and the mold member is selectively selectively thin-film coated. Photolithography and etching to form an optical waveguide pattern. According to the first and second methods, an optical waveguide pattern and an optical fiber guide are provided.
In addition, it is possible to manufacture a master mold having extremely high relative accuracy.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a configuration of an optical element master type according to Embodiment 1 of the present invention. This is intended for a single-mode optical waveguide and an optical fiber, and is about 10 cores of an optical waveguide pattern.
An optical fiber groove pattern 11 having a micron width and depth is provided, and an optical fiber guide groove 12 having a V-shaped cross section is formed adjacent to the optical waveguide groove pattern 11.

A method for manufacturing the master for an optical element shown in FIG. 1 will be described with reference to FIGS. Here, an example is shown in which quartz glass is used for a master mold.

First, a method of manufacturing the first master mold will be described with reference to FIG.

(A) An optical fiber guide groove 22 is formed on a quartz glass substrate 21 with a grinding wheel having a V-shaped cross section.
In the figure, the number of grooves is one, but about several tens can be machined without any problem. Grinding apparatuses for performing such processing are commercially available, and by controlling the temperature, the groove pitch accuracy can be reduced to ± 0.5 μm or less. Regarding the V-shape, the angle of V does not matter, but the V-shape is set so that the core of the optical fiber is located above the surface of the quartz glass substrate when the optical fiber is arranged as shown in FIG.

(B) Next, another quartz glass substrate 23 is directly bonded to a part of the V-groove processed portion. Here, the direct bonding is to bond the surfaces of the substrates to each other without using a bonding member after the surfaces of the substrates are hydrophilized. The connection interface is strongly bonded mainly by a hydrogen bond of a hydroxyl group or a covalent bond of an oxygen atom.

(C) The quartz glass substrate 23 is polished to a predetermined height with respect to the quartz glass substrate 21. The height at this time will be described later.

(D) Photolithography and dry etching are performed only on the quartz glass substrate 23 to form an optical waveguide pattern.
The groove 24 is formed. Regarding the height of the quartz glass substrate by the polishing in (c), when the optical fiber is arranged in the optical fiber guide groove 22, the height of the center of the core of the optical fiber and the center of the pattern groove of the optical waveguide is within ± 1 μm. Is polished to a height such that Also, the horizontal position of the optical waveguide pattern groove 24 on the quartz glass substrate 23 needs to be ± 1 μm, but the horizontal positioning can be adjusted by adjusting the photomask at the time of photolithography.

Thus, the master mold for an optical element of the present invention is completed.

Next, a method of manufacturing the second master mold will be described with reference to FIG.

(A) An optical fiber guide groove 32 having a V-shaped cross section is formed in a quartz glass substrate 31 in the same manner as in the first manufacturing method.

(B) Next, a thin film is deposited on a part of the V-groove processed portion to fill the V-groove portion and to form a quartz glass substrate 31.
The terrace 33 is provided with a step higher than the surface. Examples of the coating method at this time include a flame deposition method, a CVD method, a vacuum deposition method, and a sputtering method for a quartz material. After forming the film, annealing at a temperature exceeding 1000 ° C. may be performed if necessary.

(C) Terrace 33 as in the first manufacturing method
Is polished to a predetermined height. The height of the terrace 33 is the same as that described in the first manufacturing method.

(D) Terrace 33 as in the first manufacturing method.
An optical waveguide pattern 34 is formed only by photolithography and dry etching.

Thus, the master mold for an optical element of the present invention is completed.

By using the two manufacturing methods described above, a master mold for an optical element can be obtained.

The material of the optical waveguide pattern portion is not limited to quartz glass described above, but may be crystallized glass,
Even diamond, DLC, sapphire, silicon, and the like can be dry etched with a depth of several microns with high accuracy. Alternatively, a master mold can be obtained by a LIGA process using a material that can be plated such as nickel.

The optical fiber guide groove is preferably made of the same material as that of the optical waveguide pattern. However, it can be ground, and has a temperature of about 600 ° C. when forming a mold for an optical element. Any material that can withstand the temperature may be used, such as cemented carbide, cermet, or various ceramics.

The optical fiber guide groove is not limited to the V-shape, but may be rectangular, semicircular, trapezoidal, or the like.

When this master mold is used for molding a glass-based material, platinum (Pt), osmium (Os), iridium (Ir), rhodium (R)
h), coating of a protective film containing at least one of rhenium (Re), ruthenium (Ru), tantalum (Ta), and tungsten (W) as a main component prevents deterioration of the die press surface during molding. it can. When such a protective film is used, separation of the protective film can be prevented by providing an intermediate layer containing an element contained in the mold or the protective film between the mold and the mold.

In the first manufacturing method of the master mold, the substrates are joined by direct joining. However, the present invention is not limited to this, and for example, an adhesive layer may be used. When an adhesive layer is used, it is necessary to maintain the connection between the substrates within a heating temperature range when forming a mold for an optical element.

(Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings.

First, a method of manufacturing a mold for an optical element using the obtained master mold will be described.

In FIG. 5, reference numeral 51 denotes a mother glass;
Denotes a master mold for an optical element, 53 denotes a lower mold, 54 denotes a heater block, and 55 denotes a molding chamber.

As shown in FIG. 5, a mother glass 51 containing a nucleating agent is set in a molding chamber 55, and the above-mentioned master mold 52 is set opposite thereto, and an inert gas flow such as nitrogen or argon is set. Alternatively, the mother glass is softened by heating under vacuum. The heating temperature is around the softening temperature of the glass (400 to 550 ° C.). Thereafter, the glass is formed by the master mold 52, and then cooled to take out the glass. The removed glass is then placed in a high temperature furnace and heated under an inert gas flow such as nitrogen or argon, or under vacuum. The temperature at this time is 600 ° C. or higher.
Thereafter, the glass is cooled to room temperature to crystallize the glass.

Thus, a mold having an inverted shape of the master mold can be manufactured. In the present manufacturing method, since the glass size shrinks by about several% during crystallization, a master mold is prepared in consideration of this. Alternatively, in order to avoid a dimensional change, the glass may be crystallized by performing molding using a master mold in a molding machine, heating to a high temperature while pressing, and then cooling. In this case, it is possible to obtain a molding die with almost no dimensional change from the master die. A mold made of crystallized glass not only enables complex shape transfer by molding as described above, but also has extremely high mechanical strength, and is very effective for forming minute shapes such as optical waveguide patterns. is there.

The nucleating agents contained in the mother glass include titanium (Ti), zirconia (Zr), iron (F
e), oxides, sulfides, fluorides, or platinum (Pt), gold (Au), silver containing any of the elements vanadium (V), nickel (Ni), chromium (Cr), and lithium (Li) If (Ag) is satisfied, the above-described method for manufacturing a mold is effective.

The mold thus obtained has a shape as shown in FIG. In FIG. 6, 61 is an optical fiber guide groove forming portion, and 62 is an optical waveguide pattern forming portion.

It is difficult to realize such a shape by machining or etching, and the manufacturing method described in this embodiment is very effective. Also, by manufacturing a mold for an optical element by using a mold with a master mold,
A mold can be obtained at very low cost, and as a result, an optical element can be manufactured at low cost.

The shape of the master mold does not necessarily have to be the same as the intended optical element because the degree of dimensional change varies depending on the molding conditions of the mold and the annealing conditions during crystallization. . The shape of the master mold is determined according to the molding process and annealing conditions.

Regarding the mold, the material of the optical element to be molded by using the mold is not limited. For example, any material that is softened by heat, such as resin or glass, may be used. Also, like the master mold, when used for molding a glass-based material,
Platinum (Pt), osmium (Os), iridium (Ir), rhodium (Rh), rhenium (Re),
By coating a protective film containing at least one of ruthenium (Ru), tantalum (Ta), and tungsten (W) as a main component, it is possible to prevent the mold press surface from being deteriorated during molding. When such a protective film is used, by providing an intermediate layer containing an element contained in the mold or the protective film between the mold and the mold, the adhesion strength of the protective film can be increased, and Peeling of the film can be prevented.

(Embodiment 3) By using the mold for an optical element manufactured in the above-described embodiment, in the same manner as in the second embodiment, the base material heated and softened is used for the optical element. An optical element can be obtained by pressing and pressing a mold to transfer an inverted shape of the mold for optical element to the base material.

As described above, an optical element can be manufactured very efficiently by forming a mold using a master mold and forming an optical element using the mold. It goes without saying that the present invention is useful not only for the simultaneous molding of the optical waveguide pattern and the optical fiber guide described in the present embodiment but also for all optical elements that require a shape having a large dimensional difference.

Further, in the master mold and the molding die of the present invention, the press surface may have the above-described material and configuration, and the other components may be made of other materials.

Although the present embodiment has described a single-mode optical waveguide, a molding die and a master die for an optical fiber, the present invention is particularly effective for a single mode. It is also effective for optical fibers.

Although the optical waveguide pattern shape has been described using the example of the rectangular groove, it is effective regardless of the uneven shape.

It is to be noted that a molding die for an optical element can be manufactured by using a LIGA process although the cost is high in addition to the method described in the present embodiment.

[0062]

As described above, the master mold, the method for manufacturing the master mold, the mold, the method for manufacturing the mold according to the present invention,
According to the optical element manufacturing method, an optical element having a very complicated surface shape can be obtained in large quantities at low cost. Particularly, a minute shape such as an optical waveguide and an optical fiber guide having a size larger by one digit or more than this can be molded at a time with high precision.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a master type for an optical element of the present invention in Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a manufacturing process of a first optical element master mold according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a manufacturing process of a second optical element master mold according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a positional relationship between a V-groove, which is an optical fiber guide groove, and an optical fiber core according to the first embodiment.

FIG. 5 is a schematic cross-sectional view of a molding machine used for producing a molding die for an optical element according to Embodiment 2 by molding.

FIG. 6 is a configuration diagram of a molding die for an optical element according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional general optical mounting circuit board.

FIG. 8 is a configuration diagram showing an example of a molding die for simultaneously molding an optical fiber fixing groove and an optical waveguide groove.

[Explanation of symbols]

 11, 24, 34 Optical waveguide groove pattern 12, 22, 32 Optical fiber guide groove 21, 31 Quartz glass substrate 23 Raw quartz glass substrate 33 Terrace (quartz-based material thin film) 51 Mother glass 52 Master for optical element of the present invention Mold 53 Lower mold 54 Heater block 55 Molding chamber 61 Optical fiber guide groove forming part 62 Optical waveguide pattern forming part 71 Silicon substrate 72 Optical waveguide 73 Optical fiber 74 V groove block 75 Laser diode 76 Photodiode 77 Electric circuit pattern 81 Optical fiber guide Groove forming part 82 Optical waveguide pattern forming part

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Masanori Iida 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Mikihiro Shimada 1006 Okadoma Kadoma, Kazuma City Osaka Pref. (72) Inventor Hidenao Kataoka 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. (Reference) 2H047 KA12 MA05 MA07 PA21 PA24 QA05 QA07 RA00 TA00 TA44

Claims (12)

[Claims] 1. A press surface comprising a concave or convex optical waveguide pattern and a concave or convex optical fiber guide molding portion, wherein the optical waveguide pattern and the optical fiber guide molding portion have a predetermined relative positional accuracy. And a molding die for an optical element, wherein the pressed surface is made of crystallized glass. 2. A nucleating agent for crystallized glass, selected from titanium (Ti), zirconia (Zr), iron (Fe), vanadium (V), nickel (Ni), chromium (Cr) and lithium (Li). , Sulfide, fluoride, or platinum (Pt), gold (Au), silver (Ag)
The mold for an optical element according to claim 1, wherein: 3. The press surface has at least platinum (Pt), osmium (Os), iridium (Ir), and rhodium (R).
h), a protective film containing at least one of rhenium (Re), ruthenium (Ru), tantalum (Ta) and tungsten (W) as a main component is coated. The molding die for an optical element described in the above. 4. An intermediate layer between the protective film and the press surface,
The mold for an optical element according to claim 3, wherein the intermediate layer contains an element contained in any of the protective film and the pressed surface. 5. A pressing surface having a concave or convex optical waveguide pattern and a concave or convex optical fiber guide molding portion, wherein the optical waveguide pattern and the optical fiber guide molding portion have a predetermined relative positional accuracy. Master type for optical elements. 6. The press face is made of crystallized glass, quartz glass,
The master type for an optical element according to claim 5, wherein the master type is made of any one of diamond, DLC, sapphire, silicon, and nickel. 7. At least platinum (Pt), osmium (Os), iridium (Ir), rhodium (R)
h), a protective film containing at least one of rhenium (Re), ruthenium (Ru), tantalum (Ta) and tungsten (W) as a main component is coated. The master type for the described optical element. 8. An intermediate layer between the protective film and the pressing surface,
The master type for an optical element according to claim 7, wherein the intermediate layer contains an element contained in any of the protective film and the pressed surface. 9. The master mold for an optical element according to claim 5, which is pressed against a mother glass substrate containing a nucleating agent that has been heated and softened, and pressed against the substrate. Wherein the substrate is annealed at a high temperature after or while transferring the inverted shape of the mold. 10. An optical fiber guide portion is formed on a first member by grinding, a second member is provided on a part of the first member, and the second member is polished to a predetermined thickness. A method of manufacturing a master mold for an optical element, comprising forming an optical waveguide pattern on the second member by photolithography and etching. 11. An optical fiber guide portion is formed on a mold member by grinding, and the mold member is partially selectively thin-film coated to embed a part of the optical fiber guide portion and to be higher than the surface of the mold member. A method for manufacturing a master mold for an optical element, comprising: forming a terrace, polishing the terrace to a predetermined thickness, and performing photolithography and etching on the terrace to form an optical waveguide pattern. 12. The optical element molding die according to claim 1, wherein said optical element molding die is pressed against a heated and softened base material and pressed against said base material. A method for producing an optical element, comprising transferring an inverted shape of a molding die for an element.