KR20020025544A - Manufacture method of optical connector - Google Patents

Abstract

PURPOSE: A method for manufacturing an optical connector is provided to reduce a total size and easily arrange optical elements according to an optical axis using a plurality of etching mask layers. CONSTITUTION: First upper and lower etching mask layers(143,144) are deposited on both surface of a wafer and a first patterning step is performed to expose hole corresponding and V-groove corresponding areas(155,157). A second etching mask layer is deposited on the first upper and lower etching mask layers(143,144) and a second patterning step is performed to expose a micro pit corresponding area(150) and the hole corresponding area(155). The micro pit and hole corresponding areas(150,155) are etched by a predetermined depth(d1). The second etching mask layer is removed, the micro pit and hole corresponding areas(150,155) is etched by a predetermined depth(d2), and the first upper etching mask layer(143) is removed.

Description

Manufacture method of optical connector

The present invention relates to a method for manufacturing an optical connector, and more particularly, to optically align an optical axis by manufacturing different depths of V-grooves or micro feet on which an optical fiber or a ball lens is mounted using a plurality of etching mask layers. It relates to a connector manufacturing method.

Nowadays, the transmission method of the optical communication system is changing to the wavelength division multiplexing (WDM) transmission method with the increase of the transmission data in the optical communication network. As inter-network interoperability is required in such wavelength division multiplexing (WDM) systems, an optical crossing connector (OXC), or an optical connector, has become an essential core element.

Referring to FIG. 1, the optical connector includes an actuator 15 in which a micromirror 10 is disposed and drives the micromirror 10, and an optical signal to the micromirror 10 around the actuator 15. Between the input optical fiber 20 and the output optical fiber 22 for receiving and transmitting the optical signal reflected from the micromirror 10 and between the input and output optical fiber 20, 22 and the micromirror 10 It consists of the optical bench 30 arrange | positioned and the ball lens 25 and 27 which focus light. Here, the input and output optical fibers 20, 22 are connected to the V-groove 35, and the ball lenses 25, 27 are connected to the micro feet 40 connected to the V-groove 35, respectively. Is placed. The optical fibers 20, 22, the ball lens 25 and the micromirror 10 are arranged to coincide with the optical axis.

In the optical connector configured as described above, the optical signal transmitted from the input optical fiber 20 is reflected to the micromirror 10 via the ball lens 25 and then again through the predetermined ball lens 27 to output the optical fiber ( 22) to transmit an optical signal to a predetermined place. The ball lenses 25 and 27 are used to focus optical signals to reduce optical loss and to minimize optical paths.

Meanwhile, a convex corner 45 is formed at a portion where the hole 17 and the V-groove 35 for installing the actuator 15 are connected to the micropit 40. Since the actuators 15, the ball lenses 25 and 27, and the optical fibers 20 and 22 are different in size, the holes 17 accommodate these elements in order to align the center thereof with the optical axis. The V-groove 35 and the micropit 40 should be different in depth.

However, when etching in the manufacturing process of the optical connector, the optimum etching conditions such as time and temperature are different depending on the width and depth of the groove to be etched. In other words, since the holes 17, the V-grooves 35, and the micropits 40 each have different widths and depths, etching is performed according to respective etching conditions in order to be etched as patterned. Should. However, in the related art, since etching is performed by one patterning, the etching conditions are inevitably matched to one of the etching conditions or the etching conditions are set to their average conditions. Therefore, in such a case, the etching conditions are not suitable because the etching conditions are not suitable elsewhere except the standard groove, and each etching has a defect even if the average conditions are used.

In particular, in the convex corner 45 such as the micropit 40 or the hole 17, a so-called convex corner effect occurs in which the shape is not etched accurately and the pattern shape is damaged. As a result, the exact dimensions of the specification cannot be obtained as originally designed, and the arrangement of the optical elements such as the optical fibers 20, 22, the ball lenses 25, 27, and the like is changed. As a result, the alignment of the elements along the optical axis is not matched, which makes it difficult to accurately transmit the optical signal and causes light loss.

Accordingly, special corner compensation patterns 50 and 52 as shown in FIG. 2 are required to prevent pattern damage due to the convex corner effect. In other words, by considering the convex corner effect, a compensation pattern is formed on the etching mask 65 so as to suppress the occurrence of such a phenomenon during etching, and an optical connector is manufactured using the same to obtain an optical connector having a desired shape. Can be. Reference numerals 17 'and 40' denote hole corresponding regions and micropit corresponding regions formed in the etching mask 65, respectively.

A method of manufacturing an optical connector using the corner compensation patterns 50 and 52 will be described.

3A and 3B, after applying silicon dioxide 63 to the upper silicon wafer 60 in the double-side polished (100) direction, a low pressure chemical vapor deposition (LPCVD) is used for use as a silicon etching mask thereon. The silicon nitride 65 is deposited on both surfaces. Thereafter, as shown in FIG. 3C, the silicon nitride layers 65 are patterned through reactive ion etching (RIE). Corner compensation patterns 50 and 52 are added to the silicon nitride layer 65 so that the pattern shape is not damaged by the convex corner effect during the etching process.

4A and 4B, silicon oxide 72 and silicon nitride 75 are sequentially deposited on the lower silicon wafer 70, and then patterned by a reactive ion etching (RIE) process as illustrated in FIG. 4C. do.

Then, the upper and lower wafers 60 and 70 are anisotropic wet etched using KOH aqueous solution, respectively, to form a V-groove corresponding region 67 and a micropit corresponding region 68 as shown in FIGS. 3D and 4D. And hole correspondence regions 69 and 69 '. The upper wafer 60 and the lower wafer 70 thus formed are bonded to each other as shown in FIGS. 5A and 5B.

The micromirror actuator 15 is installed in the hole 17 of the optical connector thus formed, and the optical fibers 20, 22, and ball lenses 25, 27 are respectively provided in the V-groove 35 and the micropit 40. Install them in the optical axis.

Due to the corner compensation patterns 50 and 52 in the above manufacturing process, the overall pattern for manufacturing the optical connector becomes complicated and its size also becomes large.

In addition, if the position of the optical axis is different, a new type of compensation pattern is required because the etching depth must be different. That is, the design of the compensation patterns 50 and 52 according to the width or depth of the micropit 40 or the hole 17 should be changed. Therefore, there is a need to prepare a new compensation pattern each time the optical axis changes.

In particular, since the compensation patterns 50 and 52 are complicated in areas where the input / output ends of the optical fibers are adjacent to each other or where convex corner effects are large, the optical path cannot be minimized. This causes light loss due to the optical path difference. In addition, as the number of channels of the optical connector increases, it becomes more complicated, resulting in difficulty in forming a compensation pattern, and cannot satisfy the demand for miniaturization of an optical element.

The present invention has been made to solve the above problems, it is possible to simply manufacture the optical connector using a plurality of etching mask layers without the need for a corner compensation pattern to prevent the convex corner phenomenon when etching the overall size It is an object of the present invention to provide a method for manufacturing an optical connector that can reduce and easily align optical elements along an optical axis.

1 is a schematic perspective view of an optical connector according to the related art,

2 is a view schematically showing a mask pattern used in the conventional optical connector manufacturing method,

3A to 3D are views illustrating a process of manufacturing an upper substrate of an optical connector according to the related art;

4a to 4b is a view showing a process for manufacturing a lower substrate of the conventional optical connector,

5a and 5b is a view showing a form attached to the upper substrate and the lower substrate of the conventional optical connector,

6 is a perspective view of an optical connector according to the present invention;

7 is a cross-sectional view taken along the line VI-VI of FIG. 6;

8A and 8B are cross-sectional views of optical elements installed in the grooves of the optical connector according to the present invention;

9A to 9I are views showing a manufacturing process of the optical connector according to the present invention.

<Description of main part of drawing>

100 ... micromirror 103 ... hole

105 ... actuator 110 ... microfeet

115 ... V-groove 120,122 ... ball lens

125,127 ... optical fiber 130 ... optical bench

133 ... reference mark 135 ... substrate

140 ... wafer 143,144 ... first etching mask layer

145 ... Secondary etching mask layer 147 ... V-groove corresponding area

150 ... microfoot counterpart 155 ... hole counterpart

C, C '... Optical axis R ... Radius of optical fiber cross section

L ... groove half width n, d2 ... groove depth

t ... vertical distance from the surface of the substrate to the optical axis

In order to achieve the above object, the present invention provides a micropit corresponding region for depositing a first etching mask layer on both sides of a wafer and mounting a ball lens, a hole corresponding region for installing a micromirror actuator, and a V-groove corresponding region for mounting an optical fiber. First patterning the substrate to be exposed; Depositing a second mask layer on the patterned first etching mask layer and performing second patterning to expose the micropit corresponding region and the hole corresponding region; First etching the micropit corresponding region and the hole corresponding region to a predetermined depth d ₁ ; And removing the second etching mask layer, second etching the micropit corresponding region and the V-groove corresponding region to a depth d ₂ , and removing the second etching mask filling.

In addition, the present invention is characterized in that the micropit corresponding region and the V-groove corresponding region are different in depth.

In addition, the present invention, the depth d ₂ of the V-groove, the radius of the optical fiber cross-section R is the vertical distance from the wafer surface to the point where the optical fiber and the V-groove inclined plane meets m, the etching of the V-groove If the angle is α (rad), the optical axis satisfies the following equation when the optical axis is positioned t by the surface of the wafer.

Equation

In addition, the present invention is characterized in that the reference display portion is formed on each of the micromirror actuator and the wafer at a position corresponding thereto, so that the micromirror actuator can be accurately assembled to the hole corresponding area.

Hereinafter, a method of manufacturing an optical connector according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 6, an optical connector according to the present invention includes: an actuator 105 in which a plurality of micromirrors 100 are arranged in a matrix form and inserted into a hole 103 to drive the micromirrors; Optical benches in which ball lenses 120, 122, and optical fibers 125, 127 are respectively installed in the micropits 110 and V-grooves 115 corresponding to the micromirrors 100 and the optical axes, respectively. 130);

The optical fibers 125 and 127 are divided into an input optical fiber 125 and an output optical fiber 127 as described above, and the ball lens 120 is adjacent to the malleable input optical fiber 125 to focus an optical signal. The ball lens 122 focuses the optical signal reflected by the micromirror 100 and transmits the optical signal to the output optical fiber 127.

FIG. 7 is a cross-sectional view taken along the line VI-VI of FIG. 6, in which the ball lenses 120 and 122 and the optical fibers 125 and 127 are arranged to coincide with the optical axis C. Referring to FIG. As such, in the optical connector, in order to minimize the optical path and reduce the optical loss, it is important to align the optical axes of the optical devices 120 and 125. Accordingly, the width or depth of the micropit 110 or the V-groove 115 may vary depending on the position of the optical axis C.

FIG. 8A illustrates a case in which the optical axis C is positioned below the surface of the substrate 135 by a vertical distance t. The optical elements such as the ball lenses 120, 122, the optical fibers 125, 127, and the like may be optically aligned. The layout is shown to make it. Here, the optical fibers 125 and 127 will be described as an example. R is the radius of the optical fibers 125 and 127, m is the vertical distance from the surface of the substrate 135 to the point (p) where the optical fibers 125, 127 and the slope of the V-groove 115 meets, The depth of the V-groove 115 is n, and the etching angle of the V-groove is α (rad). In addition, if the half-width of the V-groove 115 is L, this L may be expressed by the following equation.

In the above formula, the width of the V-groove 115 is calculated as 2L. In addition, m and n satisfy the following equation.

In the equation for obtaining n in Equation 2, if L is substituted in L in Equation 1 instead of L, n may be represented by the following equation.

Unlike the above description, when the optical axis C 'is located above the surface of the substrate 135 as shown in FIG. 8B, it may be obtained by substituting (-t) instead of t in Equation 1 and 2 above. In addition, when the optical axis coincides with the surface of the substrate, it can be obtained by substituting 0 for t.

Meanwhile, when the actuator 105 is inserted into the hole 103 and assembled, the optical fibers 125, 127, the ball lenses 120, 122, and the micromirror 100 may be aligned with an optical axis. A reference display unit 133 serving as a reference is provided. Therefore, the actuator 105 can be easily assembled by the reference display portion 133.

Next, the manufacturing method of the optical connector which has such a structure is demonstrated.

9A and 9B, upper and lower first etching mask layers 143 and 144 are deposited on both sides of the wafer 140 in the double-side polished (100) direction, and the optical fibers 125 and 127 are mounted. First patterning to expose the V-groove corresponding region 147, the micropit corresponding region 150 in which the ball lenses 120 and 122 are mounted, and the hole corresponding region 155 in which the actuator 105 is installed. Do it. Here, the first etching mask layer 143 is preferably formed of a material consisting of Si _x N _y , and more preferably, silicon nitride (Si ₃ N ₄ ) is used.

Thereafter, a second etching mask layer 145 is deposited on the first etching mask layer 143 as in the ninth case. In addition, as shown in FIG. 9D, the micropit corresponding region 150 and the hole corresponding region 155 are exposed by a reactive ion etching (RIE) process, and then the lower first etching mask layer 144 is exposed as shown in FIG. 9E. A second patterning is performed by exposing the hole correspondence region 155. According to this second pattern, as shown in FIG. 9F, anisotropic first etching is performed from the surface of the wafer 140 by a depth d ₁ . At this time, it may be etched using potassium hydroxide (KOH) using an anisotropic wet etching process.

When the second etching mask layer 145 is removed after the first etching as described above, the V-groove corresponding region 157 is exposed together with the micropit corresponding region 150 as shown in FIG. 9G. The second etching is performed to a depth of d ₂ by the pattern of the first etching mask layer 143 thus formed. Through this process, the hole corresponding area 155 is formed as the hole 103. In this case, as in the first etching, the second etching may be performed by using an anisotropic wet etching process using potassium hydroxide (KOH). After finishing the second etching, the first etching mask layer 143 is removed as shown in FIG. 9I.

On the other hand, the etching conditions at the time of the first etching and the second etching can be etched optimally in accordance with the etching depth, the width and the like. In addition, the convex corner phenomenon may be prevented by protecting the portion of the convex corner 45 by the first etching mask layer 143 during the first etching, that is, when the micropit corresponding region 150 is etched. As such, by using two etching mask layers 143 and 145 suitable for each etching, the convex corner phenomenon can be easily prevented and the optical connector can be manufactured in a predetermined pattern.

As described above, the micropit 110 has a depth of (d ₁ + d ₂ ) and the V-groove 115 has a depth of d ₂ . Here, these depths d ₁ , d ₂ depend on the position of the optical axis C and can be determined by Equations 1 and 2 above. In addition, the (d ₁ + d ₂ ) or the d ₂ can be obtained by the equation to obtain the depth n of the groove in the equation (3). Here, as the parameters, the radius R of the optical fiber 125, 127 or micropit 110 cross section, the vertical distance t from the surface of the substrate 135 to the optical axis C, and the etching angle α are determined. The width and depth of the groove can be obtained.

First, the depth d ₂ of the V-groove 115 is equal to n obtained by Equation 2 or 3. In addition, the depth d ₁ + d ₂ of the micropit 110 may also be obtained by substituting variables determined by the ball lenses 120 and 122. That is, the radius of the end surfaces of the ball lenses 120 and 122 is referred to as R 'and the vertical distance from the surface of the wafer 140 to the point where the ball lenses 120 and 122 meet the inclined plane of the micropit 110 is measured. When m 'and the etching angle of the micro feet are alpha' (rad), when the optical axis is located above t by the wafer surface, the following equation is satisfied.

As described above, an optical connector having a plurality of optical elements having different sizes can be manufactured exactly as a pattern.

As described above, the present invention manufactures different etching depths of grooves in which each element is mounted so that each optical element having a different size is aligned with an optical axis. In order to improve the difference in etching conditions due to the difference in etching depth, a plurality of etching mask layers having respective etching patterns are provided. In this way, etching with optimal etching conditions suitable for each optical element is prevented, and convex corner phenomenon is prevented, and a separate corner compensation pattern is not required to prevent convex corner phenomenon, thus simplifying the manufacturing process and miniaturizing the optical connector. Can be. As a result, multiplexing and integrating input / output channels can be achieved.

In addition, because the pattern shape is formed accurately, the alignment of the optical axis is precisely performed, thereby minimizing the optical path of the optical input / output terminal and reducing the optical loss.

Claims (7)

Depositing a first etching mask layer on both sides of the wafer, and first patterning the micropit corresponding region for mounting the ball lens, the hole corresponding region for installing the micromirror actuator, and the V-groove corresponding region for mounting the optical fiber; Depositing a second mask layer on the patterned first etching mask layer and performing second patterning to expose the micropit corresponding region and the hole corresponding region; First etching the micropit corresponding region and the hole corresponding region to a predetermined depth d ₁ ; And removing the second etching mask layer, second etching the micropit corresponding region and the V-groove corresponding region to a depth d ₂ , and removing the second etching mask layer. Manufacturing method. The method of claim 1, wherein the micropit corresponding region and the V-groove corresponding region have different depths. The depth d ₂ of the V-groove according to claim 1 or ₂ , If the radius of the optical fiber cross section is R, the vertical distance from the wafer surface to the point where the optical fiber meets the V-groove inclined plane is m, and the etching angle of the V-groove is α (rad). The optical connector manufacturing method characterized by satisfying the following equation when positioned above by t. Equation The depth of the micro feet (d ₁ + d ₂ ) of claim 1 or 2, If the radius of the ball lens cross section is R 'and the vertical distance from the wafer surface to the point where the ball lens and the micropit inclined plane meet is m' and the etching angle of the ball lens is α (rad), the optical axis is the wafer. When positioned above the surface by t, the optical connector manufacturing method characterized by the following equation. The method of claim 1, wherein the first etching mask layer and the second etching mask layer are manufactured using Si _x N _y . The method of claim 1, wherein the first mask layer and the second etching mask layer are formed using silicon nitride (Si ₃ N ₄ ). The optical connector manufacturing method according to claim 1, wherein a reference display portion is formed on each of the micromirror actuator and a wafer at a position corresponding to the micromirror actuator, so that the micromirror actuator can be accurately assembled to the hole corresponding region.