KR101835456B1 - Manufacturing method of optical fiber array block - Google Patents

Abstract

A method of fabricating an optical fiber array block according to an embodiment of the present invention includes: forming an etch mask pattern exposing a region to be seeded on a silicon substrate; Dry etching the exposed silicon substrate to form a trench; Forming a plurality of V-grooves by anisotropically etching the silicon substrate exposed on the bottom surface of the trench by wet etching; Placing optical fibers in the V-grooves; And applying UV curing epoxy to the placed optical fibers, raising the cover plate, and fixing the optical fibers by irradiating UV light.

Description

TECHNICAL FIELD [0001] The present invention relates to a manufacturing method of an optical fiber array block,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an optical fiber array block having a V-groove for mounting an optical fiber, which is used in a communication method using an optical fiber.

The optical fiber array block may be divided into a plurality of optical fibers such as an optical splitter, an optical coupler, an arrayed waveguide grating (AWG), an optical switch, a multiplexer / demultiplexer, It is a device that facilitates alignment and fixing of optical fibers when packaging optical fibers and chips of strands.

In general, the optical fiber array block includes a substrate on which a plurality of V grooves are formed to facilitate alignment of optical fibers, a plurality of optical fibers aligned in the V groove, a cover plate for pressing and fixing the plurality of optical fibers, And an adhesive filled between the cover plate and the cover plate.

The silicon (Si) substrate as the V-groove substrate can easily make very precise V-grooves by using the characteristics of silicon, and can be mass-produced, thereby enabling cost reduction. However, since the depth of the V-groove is determined in the silicon substrate, it is difficult to fabricate a V-groove having a depth sufficient for the optical fiber to be sufficiently seated, and thus the reliability of the optical fiber array block is poor. On the other hand, since quartz has a small thermal expansion coefficient, it has excellent thermal stability, UV curing is easy, and V groove is manufactured by machining using a grinding machine, so that it is possible to fabricate a sufficiently deep V groove Thereby making a highly reliable optical fiber array block. However, since the above-mentioned quartz is machined, when a large number of arrays of 16 arrays or more are manufactured, the manufacturing time is long and the recovery rate is low, which causes a disadvantage that the manufacturing cost is increased.

It is an object of the present invention to provide a method of manufacturing an optical fiber array block which is inexpensive and has high reliability.

According to another aspect of the present invention, there is provided a method of fabricating an optical fiber array block, including: forming an etch mask pattern exposing a region to be seeded on a silicon substrate; Dry etching the exposed silicon substrate to form a trench; Forming a plurality of V-grooves by anisotropically etching the silicon substrate exposed on the bottom surface of the trench by wet etching; Placing optical fibers in the V-grooves; And applying UV curing epoxy to the placed optical fibers, raising the cover plate, and fixing the optical fibers by irradiating UV light.

According to an embodiment of the present invention, an optical fiber mounting portion including a V groove in which an optical fiber can be sufficiently placed through a combination of dry etch and wet etch is formed on a silicon substrate, By reducing the distance between the optical fiber array and the cover plate to reduce the amount of epoxy resin used as an adhesive, it is possible to manufacture an optical fiber array block with high reliability and low cost. The present invention can take advantage of the material advantages of silicon and quartz used in optical fiber array blocks. In addition, the cost of an optical communication component such as a low-cost optical splitter can be reduced by using the optical fiber array block of the present invention.

1 is a cross-sectional view of an optical fiber array block according to an embodiment of the present invention.
FIGS. 2A to 2M are cross-sectional views illustrating a method of manufacturing an optical fiber array block according to an embodiment of the present invention.
3 is a scanning electron microscope (SEM) photograph showing an optical fiber mounting part including a V-groove fabricated on a silicon substrate for an optical fiber array block according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. It should be understood, however, that the embodiments of the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the invention to those skilled in the art. It is preferred that the invention be interpreted as providing a more complete description of the invention. Therefore, the elements, shapes, sizes, and the like in the drawings may be exaggerated for clarity of description, and the elements denoted by the same reference numerals in the drawings are the same elements.

1 is a cross-sectional view of an optical fiber array block according to an embodiment of the present invention.

1, an optical fiber array block 100 according to an embodiment of the present invention includes a silicon substrate 110 having an optical fiber mounting portion F and a quartz wafer (not shown) directly bonded under the silicon substrate 110 a cover plate 160 provided on the at least one optical fiber 140 mounted on the optical fiber mounting portion F and a cover plate 160 provided on the at least one optical fiber 140 mounted on the optical fiber mounting portion F, And an adhesive layer 150 filled between the bonded substrate stack 130 and the cover plate 160.

The optical fiber mounting portion F is provided under the vertical sidewalls 110a and the vertical sidewalls 110a so that the outermost inclined surfaces extend from the bottom of the vertical sidewalls 110a May be provided in one or more neighboring V grooves 110c.

The optical fiber mounting portion F is provided under the vertical sidewalls 110a and the vertical sidewalls 110a and has a V-groove 110c extending from the bottom of the vertical sidewalls 110a And can be provided in a compartment.

The vertical sidewalls 110a may be provided at a first depth of 40 [mu] m to 60 [mu] m from the top surface of the silicon substrate 110. [ The V-grooves 110c may be provided at a second depth of 80 to 100 m from the bottom of the vertical sidewalls 110a. The optical fiber mounting portion F provides a third depth from the top surface of the silicon substrate 110 to the bottom surface of the V grooves 110c by adding the first depth and the second depth, .

The surface of the silicon substrate 110 has a (110) crystal face. The inclined plane of the V grooves 110c has an inclination angle of 54.7 degrees with the (111) crystal face.

The V-grooves 110c may be provided adjacent to each other. Although not shown, the V-shaped grooves 110c may be spaced apart in parallel in one direction with a flat surface of the silicon substrate 110 interposed therebetween.

The optical fibers 140 may be provided with a diameter of about 125 탆. The optical fibers 140 protrude from the top surface of the silicon substrate 110 within 50 m due to the vertical sidewalls 110a provided at the uppermost portion of the optical fiber mounting portion F, Can be mounted deep enough in the V-grooves 110c of the portion (F).

The V-shaped grooves 110c minimize the stress concentration generated in the optical fibers 140, thereby minimizing the occurrence of optical loss, thereby providing the optical fiber array block 100.

The cover plate 160 fixes the optical fibers 140 and protects the optical fibers 140 from the external environment. The cover plate 160 may be provided on the optical fibers 140 and the silicon-quartz directly bonded substrate 130. For example, the cover plate 160 may be a glass or quartz substrate. Here, the silicon-quartz bonded substrate 130 including the optical fiber mounting part F may constitute an optical fiber array. In the silicon-quartz bonded substrate 130, the quartz wafer 120 may be omitted.

The adhesive layer 150 may be made of, for example, an epoxy for UV curing. The adhesive layer 150 may be provided in the V-grooves 110c under the optical fibers 140. [

The optical fiber array block 100 has high reliability since the space between the silicon-quartz bonded substrate 130, i.e., the optical fiber array, and the cover plate 160 is narrow and the amount of the epoxy used is small.

The optical fiber array block 100 may be manufactured by forming V grooves 110c on the silicon substrate 110 and bonding the quartz wafer 120 under the silicon substrate 110, Silicone and quartz can take advantage of all the material advantages.

Hereinafter, a method of fabricating an optical fiber array block according to an embodiment of the present invention will be described with reference to FIGS. 2A to 2M.

FIGS. 2A to 2M are cross-sectional views illustrating a method of manufacturing an optical fiber array block according to an embodiment of the present invention, 3 is a scanning electron microscope (SEM) photograph showing an optical fiber mounting part including a V-groove fabricated on a silicon substrate for an optical fiber array block according to an embodiment of the present invention.

Referring to FIG. 2A, an etching mask layer 112 is formed on a silicon substrate 110. The silicon substrate 110 may be a substrate having a native oxide removed through RCA cleaning or the like. The silicon substrate 110 may have a V groove for precisely aligning the optical fibers 140 (see FIG. 2K) with a wet etch characteristic unique to the crystal plane It is advantageous in mass production, and mass production is possible, which is economical. The surface of the silicon substrate 110 has a (110) crystal face.

The etch mask layer 112 may be formed of a material having an etch selectivity different from that of the silicon substrate 110. The etch mask layer 112 may be formed of a silicon oxide film (SiO ₂ ) or a silicon nitride film (Si ₃ N ₄ ). The silicon oxide film (SiO ₂ ) may be formed to a thickness of 1000 Å to 5000 Å. The silicon nitride film (Si ₃ N ₄ ) may be formed to a thickness of 500 Å to 1000 Å.

For example, the silicon oxide film (SiO ₂ ) may be a thermal oxide film. For example, the thermal oxide film may be formed at a temperature of 700 ° C to 1000 ° C for 10 minutes to 15 minutes using ₂ slm to 15 slm of O ₂ gas.

Referring to FIG. 2B, a photoresist layer 114 is formed on the etch mask layer 112. The photoresist layer 114 may be formed by applying a positive or negative photoresist on the etch mask layer 112. Here, for convenience of explanation, a photoresist film 114 made of a positive photosensitive material is shown. For example, the photoresist 114 may be formed by applying a positive photosensitive material of AZ series (Mg-Al-Zn alloy) at a speed of 1000 rpm to 3000 rpm using a spin coater.

Referring to FIG. 2C, an exposure mask 116 is placed on the photoresist layer 114, followed by an exposure process.

The exposure mask 116 may include the light transmitting portions 116a and the light shielding portions 116b. The light transmissive portions 116a correspond to the regions to be crystallized of the silicon substrate 110 and the light shielding portions 116b correspond to the regions except the regions to be crystallized of the silicon substrate 110. [ The regions to be grained of the silicon substrate 110 may have at least one rectangular shape parallel to one direction.

The exposure process may be performed by irradiating ultraviolet (UV) light. As a result, the photoresist 114 corresponding to the light transmitting portions 116a is changed to the exposing portions A. The exposure mask 116 is removed after the exposure process is completed.

Referring to FIG. 2D, the exposed portions A (see FIG. 2C) of the photoresist layer 114 (see FIG. 2C) are developed. The developing process can be performed using a strip solution such as, for example, EKC 830 (EKC Technologies).

As a result, the exposed portions A (see FIG. 2C) of the photoresist 114 (see FIG. 2C) are removed and the photoresist 114 (see FIG. 2C) corresponding to the light-shielded portions 116b A photoresist pattern 114a having at least one or more first openings O1 for exposing a part of the surface of the etch mask layer 112 is formed.

After the photoresist pattern 114a is formed, a bake process may be further performed to cure the photoresist pattern 114a.

Referring to FIG. 2E, the etch mask layer 112 (see FIG. 2D) exposed at the bottom of the first openings O1 of the photoresist pattern 114a is etched.

The etching may be performed by a dry etch process. The dry etching process may be performed by using a mixed gas comprising an O ₂ gas, an oxygen-containing gas, CxFy (x, y is a positive integer) gas, CxHyFz (x, y, z is a positive integer) gas, an inert gas, Gas can be used as an etching gas.

The etch mask pattern 112 (see FIG. 2D) is selectively removed to form at least one second opening O2 exposing the regions to be crystallized in the silicon substrate 110 112a are formed.

Referring to FIG. 2F, the photoresist pattern 114a (see FIG. 2E) is removed. The removal process of the photoresist pattern 114a (see FIG. 2E) may be performed by a dry etching process or a wet etching process. For example, the dry etching process may be performed using an O ₂ plasma. For example, the wet etching process can be performed by using a nanostrip solution at a temperature of 70 ° C to 100 ° C for 10 minutes to 20 minutes.

As a result, the photoresist pattern 114a (see FIG. 2E) is selectively removed, and only the etch mask pattern 112a remains on the silicon substrate 110.

Referring to FIG. 2G, the exposed silicon substrate 110 is etched using the etch mask pattern 112a as an etch mask.

The etching can be performed using a dry etching process. The dry etching process can be performed for 5 to 10 minutes using CxFy (x, y is a positive integer) or CxHyFz (x, y, z is a positive integer) type gas as an etching gas. At this time, the etching depth may be formed to a first depth of 40 to 60 탆 from the upper surface of the silicon substrate 110. For example, the dry etching process can be performed for about 5 minutes using CF ₄ gas as an etching gas.

As a result, the exposed silicon substrate 110 is etched to form at least one trench T having the first depth from the upper surface of the silicon substrate 110. The trenches T may be formed of vertical sidewalls 110a and a bottom surface 110b, and may have a rectangular shape parallel to one direction.

Although not shown, an oxidation process may be further performed after the dry etching process to compensate for etching damage.

Referring to FIG. 2J, the quartz wafer 120 is directly bonded under the silicon substrate 110 including the optical fiber mounting portion F.

The quartz wafer 120 may be provided to mitigate the difference in thermal expansion coefficient between the optical splitter chip (not shown) to be mounted on the optical fiber array block 100 (see FIG. 2M) .

Referring to FIGS. 2h and 3, the etch mask pattern 112a is used as an etch mask to expose the bottom surface 110b (see FIG. 2g) of the trenches T The exposed silicon substrate 110 is etched. At this time, the etch depth may be formed at a second depth of 80 占 퐉 to 100 占 퐉 from the bottom surface 110b (see FIG. 2g) of the trenches T or the bottom surface of the vertical side walls 110a.

The etching may be performed using a wet etching process. Preferably, the wet etching process may be performed using a potassium hydroxide (KOH) solution or a tetramethyl-ammonium hydroxide (TMAH) solution. For example, the wet etching process can be performed at a temperature of 75 ° C to 95 ° C for 150 to 170 minutes using a 20 wt% TMAH solution.

The silicon substrate 110 is anisotropically etched due to the crystal orientation dependent etching property when the KOH or TMAH solution is used as an etching medium. That is, when the exposed silicon substrate 110 is etched using the etch mask pattern 112a as the etch mask and the crystal plane is the surface, at least one or more deep V grooves 111, , 110c are formed. This is because silicon exhibits a different etching rate depending on the crystal direction because the degree of atom density is different according to the crystal direction. At this time, the etching rate as the direction having the lowest activation energy is the highest.

The inclined plane of the V grooves 110c has an inclination angle of 54.7 degrees with the (111) crystal face. The inclination angle is a factor fixed to the silicon substrate 110 whose surface has a (110) crystal face.

2H and FIG. 3, the uppermost portion of the silicon substrate 110 is provided with the uppermost sidewalls 110a and the uppermost sidewalls 110a, An optical fiber mounting portion F is formed which is divided into at least one adjacent V grooves 110c extending from the bottom of the vertical side walls 110a.

Therefore, the optical fiber mounting portion F is disposed between the first depth of the vertical sidewalls 110a from the upper surface of the silicon substrate 110 to the bottom of the V grooves 110c, The second depth may be formed to have a third depth, that is, a depth of 120 mu m to 160 mu m.

The V grooves 110c may be formed adjacent to each other as shown in FIG. 2 while the silicon substrate 110 between the trenches T (see FIG. 2g) is etched together during the etching of the V grooves 110c . 3, the V-shaped grooves 110c may be formed in parallel to the silicon substrate 110 in parallel in one direction with a flat surface of the silicon substrate 110 interposed therebetween, And can be formed spaced apart. Accordingly, the optical fiber mounting portion F is provided under the vertical sidewalls 110a and the vertical sidewalls 110a and includes a V (not shown) extending from the bottom of the vertical sidewalls 110a, And the groove 110c. In FIG. 3, portions protruding from both sides of the lower side of the vertical sidewalls 110a are etched so as not to occur in the etching process.

The V-grooves 110c minimize the concentration of stress generated in the optical fibers 140 (see FIG. 2K) There is an effect of providing the optical fiber array block 100 (see FIG. 2M).

Referring to FIG. 2I, the etch mask pattern 112a (see FIG. 2H) is removed. The etch mask pattern 112a (see FIG. 2H) may be removed using a dry etch process or a wet etch process.

If the etch mask pattern 112a (see FIG. 2H) is the silicon oxide film (SiO ₂ ), the etch mask pattern 112a (see FIG. 2H) can be removed by a wet etching process using an HF mixed aqueous solution. Alternatively, if the etching mask pattern (reference 112a, FIG. 2h) wherein the silicon nitride (Si ₃ N _4), the etching mask pattern as an example (see 112a, Fig. 2h) is using a phosphoric acid (H ₃ PO ₄₎ solution It can be removed by wet etching process.

Thus, the etch mask pattern 112a (see FIG. 2H) is selectively removed to expose the surface of the silicon substrate 110 including the optical fiber mounting portion F. FIG.

Thereby, the silicon-quartz direct bonded substrate 130 formed of the silicon substrate 110 and the quartz 120 including the optical fiber mounting portion F is formed. Accordingly, at least one V-shaped groove 110c is formed on the silicon substrate 110 to form an optical fiber array.

The silicon-quartz directly bonded substrate 130 directly joins the quartz wafer 120 to the silicon substrate 110 while making the V-shaped grooves 110c on the silicon substrate 110 at a low cost, The material advantages of the silicon and quartz used in the optical fiber array block 100 (see FIG.

Referring to FIG. 2K, at least one optical fiber 140 is mounted on the optical fiber mounting portion F of the silicon-quartz bonded substrate 130.

The optical fibers 140 have a diameter of about 125 mu m. The optical fibers 140 are seated sufficiently deeply in the V grooves 110c of the optical fiber mounting portion F by the vertical sidewalls 110a provided on the outermost upper portion of the optical fiber mounting portion F, .

However, since the optical fibers 140 are not completely seated in the optical fiber mounting portion F due to the shape of the V grooves 110c, the upper surface of the optical fibers 140 may protrude within about 50 m from the upper surface of the silicon substrate 110 have.

Referring to FIG. 21, an adhesive layer 150 is formed by applying an adhesive on the optical fibers 140 and the silicon-quartz bonded substrate 130 that are seated in the optical fiber mounting portion F. FIG.

The adhesive layer 150 may be formed by sufficiently applying the adhesive to the optical fibers 140 so that the adhesive can penetrate the optical fibers 140. In one example, the adhesive layer 150 may be an epoxy for UV curing.

Referring to FIG. 2M, a cover plate 160 is placed on the adhesive layer 150, and then UV is irradiated to adhere the silicon-quartz bonded substrate 130 and the cover plate 160 to the optical fibers 140).

The cover plate 160 fixes the optical fibers 140 and protects the optical fibers 140 from the external environment. For example, the cover plate 160 may be made of glass or quartz.

The cover plate 160 provided on the optical fibers 140 mounted on the optical fiber mounting portion F and the silicon plate 140 formed on the optical fibers 140 mounted on the optical fiber mounting portion F, The optical fiber array block 100 including the adhesive layer 150 filled between the quartz direct bonding substrate 130 and the cover plate 160 is completed.

In general, when the gap between the silicon-quartz bonded substrate 130, i.e., the optical fiber array and the cover plate 160 is large, the amount of the epoxy injected between the silicon-quartz bonded substrate 130 and the cover plate 160 increases. Shrink and expand Delamination phenomenon of the epoxy occurs, which causes the optical loss of the optical fiber.

According to an embodiment of the present invention, the optical fiber mounting portion F may be formed through a combination of dry etching and wet etching of the silicon substrate 110 to sufficiently expose the optical fibers 140 to the V grooves 110c The spacing between the optical fiber array and the cover plate 160 can be reduced to reduce the amount of epoxy used. Therefore, the optical fiber array block 100 having high reliability and low cost can be manufactured.

The manufacturing cost of an optical fiber array block in an optical communication component such as an optical distributor accounts for 1/3 of the total, and the use of the optical fiber array block 100 of the present invention has an advantage that the price of an optical communication component such as an optical splitter can be reduced.

In an embodiment of the present invention, the quartz wafer 120 is directly bonded under the silicon substrate 110 after the wet etching process for forming the V grooves 110c. However, the present invention is not limited thereto The quartz wafer 120 may be directly bonded under the silicon substrate 110 after the dry etching process for forming the trenches T before forming the V grooves 110c. The latter is more advantageous in terms of bonding since the direct bonding proceeds in a state in which no warpage of the silicon substrate 110 is caused by the formation of the V grooves 110c.

The present invention is not limited by the above-described embodiments and the accompanying drawings, but is intended to be limited only by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

100: Optical fiber array block 110: Silicon substrate
120: Quartz 130: Silicon-quartz direct bonded substrate
140: optical fiber 150: adhesive layer
160: cover plate F: optical fiber mounting part
110a: vertical side wall 110c: V-groove

Claims (10)

Forming an etch mask pattern exposing a region to be crystallized on a silicon substrate;
Dry-etching the exposed silicon substrate to form a plurality of trenches;
Anisotropically etching the silicon substrate exposed on a bottom surface and an inner surface of the trenches by wet etching to form a mounting portion;
Placing optical fibers on the mounting portion; And
Providing a cover plate covering the optical fibers on the silicon substrate to fix the optical fibers,
The mounting portion includes:
A pair of side walls perpendicular to the upper surface of the silicon substrate and facing each other; And
And a plurality of V grooves extending downward from the pair of side walls and formed to be adjacent to each other.
The method according to claim 1,
The step of fixing the optical fibers comprises:
Applying UV curing epoxy to the optical fibers;
Providing the cover plate to cover the optical fibers coated with the UV curing epoxy; And
And irradiating the UV curable epoxy with UV light to form an adhesive film between the optical fibers and the cover plate.
delete The method according to claim 1,
Wherein the V-grooves have inclined surfaces of 54.7 degrees with respect to the upper surface of the silicon substrate.
The method according to claim 1,
Further comprising bonding a quartz wafer under the silicon substrate prior to seating the optical fibers in the V-grooves.
A mounting portion recessed from an upper surface of the substrate and extending in one direction;
Optical fibers disposed in the mounting portion;
A cover plate disposed on the substrate, the cover plate covering the optical fibers; And
And an adhesive layer interposed between the optical fibers and the cover plate,
The mounting portion includes:
A pair of side walls perpendicular to the upper surface of the substrate and facing each other; And
And a plurality of V-shaped grooves disposed between the pair of side walls,
Wherein the V-grooves extend downward from the pair of side walls and are formed adjacent to each other.
The method according to claim 6,
Wherein the optical fibers are disposed on the V-grooves.
The method according to claim 6,
Wherein the V-grooves include sloped surfaces inclined at 54.7 degrees relative to the top surface of the substrate.
The method according to claim 6,
Wherein an upper portion of the optical fiber protrudes above the upper surface of the substrate.
The method according to claim 6,
Wherein the substrate is a silicon substrate.

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