TW562951B - Electromagnetic actuation optical switch and the fabrication method thereof - Google Patents

Abstract

The present invention relates to an electromagnetic actuation optical switch and the fabrication method thereof. The switch comprises a cantilever having a mirror on top of it. A magnetic film is disposed under the cantilever, a planar coil is disposed at the corresponding position. The coil and the magnetic film together form an magnetic actuation portion in coordinate with a torsion bar on the cantilever, so that the cantilever can proceed the teeterboard movement to pull the mirror to move vertically, so as to function as an optical switch. The optical switch disclosed by the present invention is made by the IC process of MEMS technology. Firstly, the cantilever, the torsion bar, the magnetic film and the mirror are formed on the first substrate. Then the coil is formed on the second substrate. Finally, the positioning grooves of the first substrate and the second substrate are used to precisely align and combine to complete the packaging of the optical switch.

Description

562951 V. Description of the invention (1) [Application field of the invention] The present invention relates to an optical switch, especially an electromagnetically driven optical switch manufactured by micro-electromechanical technology. [Background of the Invention] In the development trend of optical communication network technology, it has become the main trend to increase the transmission bandwidth by high-density division multiplexing technology (DWDM). However, the growth rate of the multiples of the bandwidth carrying the signal has caused a heavy burden on the network node equipment that manages the signal, making it impossible to meet the requirements with high-speed electronic components for switching or routing. Therefore, the future trend is to hope that the optical signals can be exchanged in the optical domain as much as possible in the node to increase the processing speed and maintain the light transparency. Therefore, it is used in the optical domain. Doing the optical switch (0 ptica 1 Switch, or light valve) of the exchange core has become the trend of technological development. Optical switch refers to a device that enables an optical signal to be switched from an input port (Port) to a destination output port. It is used in optical communication network nodes (OXC, Optical Cross Connect), optical plug multitasking (0ADM, Optical Add & Drop Multiplexer) system and other all-optical switching core (Switch Core) technology to complete functions such as error return (Restoration) and switching.

The currently proposed technologies for optical switches include those disclosed using thermal bubble, liquid crystal, micro motor, and micro-electromechanical (MEMS) technology. One of the micro-electro-mechanical optical switch technologies is an electromagnetically driven optical switch, such as S i 1 ic ο η M icr 〇0 ptica 1

Page 4 562951 V. Description of the invention (2)

Switching Device with an Electromagnetically Operated Cantilever, as shown in Figure 1, it uses a coil 11A wound around an electromagnetic material 10A and a magnetic film 12A to form an electromagnetic drive unit, which guides the cantilever 1 3A to produce vertical displacement. The mirror 14A on the cantilever 13A blocks the passage of the fiber 15A. Another proposed optical-on relationship is published in Se 1 f Aligned Vertical Mirrors and V-grooves Applied to a Self-Latching Matrix Switch for Optical Networks in the I EEE journal. As shown in FIG. 2, it uses a coil 1 1 B wound around an electromagnetic material i 〇β and a magnetic film 1 2B of a magnetically permeable alloy (perma 1 1 oy) material to form an electromagnetic drive unit to guide The cantilever 1 3 B generates displacement, and the mirror surface 1 4 B on the cantilever 1 3 B blocks the passage of the optical fiber. The technical characteristics of the above two types of electromagnetically driven optical switches are to use a cantilever to generate vertical displacement through the driving of the electromagnetic coil to achieve the purpose of the optical switch; however, there are some technical issues, one of which is to increase the cantilever. The amount of displacement must increase the length of the cantilever, but increasing the length will slow down the switching speed; the other is to use a large electromagnetic coil to drive the mirror surface, and the coil must be aligned and adhered below the mirror surface using an additional process. Furthermore, driving mirrors with large coils is prone to corsstalk and cannot control individual mirrors accurately, which not only fails to improve reliability, but also cannot miniaturize and accumulate components.

The other kind of light-on relationship is the one of the Electromagnetic optical switch for optical network communication published in the journal Magnetism and Magnetic Materials.

Page 5 562951 V. Description of the invention (3) Optical switch 'as shown in Figure 3, which uses a flat coil (not shown) on the electromagnet], and a nickel-iron magnetic permeability The alloy material 1 OC film 1 2 C constitutes an electromagnetic drive unit, which guides the cantilever 1 3 C to generate a displacement ^ that hinders the passage of the optical fiber. Of course, in order to increase the amount of displacement, it is necessary to use rigid # to accompany polyimide (Polyimide) film, but in order to make this film, the technology of laser micro-machining (laser micro-machining) is used; 4 film engraved 'not only can not achieve the purpose of mass production, the system is not compatible with IC ^. Quan Yehe In summary, high reliability, high accuracy, low insertion loss, and high swi tch speed are the current development trends of optical switch technology. [Objective and Summary of the Invention] As mentioned above, the main objective of the present invention is to provide a high-switching and fast-production optical switch, which uses two sets of electromagnetic drive units to cooperate with a torsion bar formed on the cantilever to increase the displacement of the cantilever. Measurement and restoring force to speed up switching. Another object of the present invention is to provide a high-reliability and high-accuracy optical switch. A torsion bar is used to make the cantilever into a suspension structure, so that the cantilever cooperates with two sets of electromagnetic driving devices. The drive performs seesaw movement to improve reliability and accuracy. A second object of the present invention is to provide a low corsstalk effect. The simulation results show that the magnetic force required to drive the optical switch and the magnetic force generated by the adjacent magnetic film are seven orders of magnitude larger. Yet another object of the present invention is to provide a light with better restoring power.

562951

V. Description of the invention (4) The switch uses the torsion buckle on the cantilever to open the door from ^ A a > as a $ shop force sensor, to assist the cantilever to generate vertical displacement and & supply core # to return to the original position. The required resilience. In order to achieve the above purpose, the optical switch disclosed in the present invention mainly includes two parts. The first part is a seesaw unit (teeterb〇ard p0rti〇n). The second part is an electromagnetic drive unit (actuati0n portion). The unit and the ferromagnetic drive unit are formed together in a housing. The seesaw unit mainly includes a cantilever, a torsion bar, and a mirror, and the seesaw unit is formed in a shell. The torsion bar and the cantilever are completed in the same process step. The cantilever is driven by an electromagnetic coil to produce vertical displacement. Its movement pattern is similar to that of a seesaw, thereby blocking the passage of light or passing the beam. The above mirror surface is located above one side of the cantilever, and its position is the path through which the optical fiber passes. The cantilever, the torsion bar and the mirror are integrally formed. The structure is formed on a silicon substrate, and the silicon substrate is etched by dry etching or wet etching to complete the above-mentioned components. The second part is mainly an electromagnetic drive unit, which includes a spiral inductor formed by a ferromagnetic coil, which is located in a groove at the bottom of the cover. As an electromagnetic drive coil, it is made by electroplating. The material of the coil is highly conductive. Metal, more commonly used conductive metals include metals such as gold or copper; and the method of making the groove can be achieved by dry etching or wet etching. After the groove etching is completed, the metal is plated in the groove. To complete the production of the coil.

Page 7 562951 V. Description of the invention (5) In addition, an electromagnetic drive unit is formed under the two sides of the cantilever. The magnetic film 'and the spiral inductor are formed together, and the conductive material d :: is completed by electroplating. In addition, the outer side of the magnetic medium must be STOPPER. It is made of a small piece of ferromagnetic material. The stopper is completed in the same process step. The material composition is the same as that of the magnetic film. With the tether pad, when the spiral inductance is generated as a buffer-buffer when the vertical displacement movement is avoided, avoiding the cantilever = attracting the magnetic film, the stopper can be used as arm. #Directly hit the bottom of the groove to protect the + part of the disclosure disclosed in the present invention. The process of the second part of the 2-switch switch is mainly divided into three magnetic films and stoppers: 20%, single rocker, including electromagnetic The driving unit is formed with an electromagnetic driving unit, ++ B, and an upper half of the cover. The second part is divided into the cover: the spiral inductor and the lower half of the cover #. The side wall of the third half is precisely aligned with the outer cover, and there is a positioning groove in the side wall of the circle I of the optical fiber on the outer cover. The use of one light and two is used to design the upper and lower parts. V-groove for easy alignment. In the system groove, Ul ^ my f ΐ1 ^ Γ) is placed on the upper and lower silicon wafers, and the silicon wafer fine dish glue (g 1 Ue) is heated and pressurized to separate the upper and lower two ... 丨 肖For imitation prostitutes > *: as ... 562951 V. Description of the invention (6) Figure 4 to Figure 6, Figure 4 is a side view of the electromagnetic, moving 1 switch disclosed in the invention, Fig. 5 is a top view of the electromagnetic drive switch disclosed in the present invention, and Fig. 6 is an electromagnetic drive composition disclosed in the present invention. As shown in FIG. 4, the electromagnetically driven optical switch disclosed in the present invention mainly includes two parts (separated by dashed lines in the figure), which are divided into two parts, the first part is a teeterb〇ard portion 1〇〇 'The second part is an electromagnetic drive unit 200, and the seesaw unit 100 and the electromagnetic drive unit 2000 are jointly formed in an outer cover 300. The plate winding unit i〇〇 mainly includes four constituent units, namely suspension cane UeVer), the first torsion bar 121 (torsion bar) 121, the second torsion bar 122, and the mirror 13 (mirror). As shown, the seesaw unit 100 is formed in a cover 300 (sheU). The cantilever n 0 described in the UI is a sheet-like structure, and there is no full j contact with the outer cover 300, and a movable space is left to facilitate the vertical displacement of the cantilever. The drought transport parts include a first torsion bar 121 and At the 4th position of the second torsion bar, the first torsion bar, 121 attaches μ 11 〇 i ί ί Secret / 3 1 〇, the second torsion bar 1 2 2 its role is to maintain balance, ^: The restoring force required for restoring. The torsion bar can also be as shown in FIG. 7, which includes only the first torsion bar 121. The first torsion bar 121: In addition to providing the cantilever restoring force, the other torsion bar 1 22 makes it a seesaw structure, which is driven by an electromagnetic coil to generate a plate-like motion pattern. To block the passage of light or pass the beam

562951 V. Description of the invention (7) Over ° The above-mentioned mirror surface 1 30 is located above the right end of the cantilever i 10 (in the direction shown in the figure), as shown in the path of the light beam. The cantilever 11 0, the first torsion bar member 1 2 1, the second torsion bar member 22, and the mirror surface 1 30 are integrally formed. The structure is made on a silicon substrate using the I c process, and the dry or wet etching is used. Technology etches silicon wafers to complete.

The electromagnetic drive unit 200 includes a first spiral inductor 2 11 and a second spiral inductor 2 1 2 (as shown in FIG. 4 and FIG. 6) formed by a ferromagnetic coil. As the electromagnetic drive coil, the first A spiral inductor 2 11 is formed in the first groove 2 4 1 located at the bottom 3 2 0 of the housing, and a second spiral inductor 2 1 2 is formed in the second groove 24 2. The first spiral inductor 211 and the second spiral inductor 212 is made by electroplating. Its composition material is a metal with good conductivity. The more commonly used conductive metals include metals such as gold or copper, and the first groove 2 4 1 and the second groove 2 4 2 The manufacturing method can be achieved by dry etching or wet etching. The first spiral inductor 2 11 and the second spiral inductor 2 1 2 are connected to the first groove 241 and the second groove 24 2. The first groove 241 and the second groove 242 are formed.

In addition, a first magnetic film 2 2 1 and a second magnetic film 2 2 2 are formed below both sides of the cantilever 110, and the first magnetic film 2 11 and the mirror surface 1 30 are located on different surfaces on the same side of the cantilever 110. The second The magnetic film 2 2 2 is on the other side of the cantilever 11 〇. The first magnetic film 221 and the first spiral inductor 211 together form the electromagnetic driving unit 200, and the second magnetic film 22 2 and the second spiral inductor 21 2 are another Electromagnetic drive unit. The manufacturing method of the first magnetic film 2 2 1 is completed by electroplating. An electro-active material is plated on the cantilever 11 〇, and the material can be nickel-iron alloy (Ni-Fe al loy

Page 10 562951 V. Description of the invention (8) ^, one of nickel-cobalt alloy (Ni-Co alloy) or nickel metal (Ni metal) 1. In addition, a small piece of ferromagnetic material outside the first magnetic film 221 serves as a first stopper (STOPE) 231, and a small piece of ferromagnetic material outside the second magnetic film 22 2 serves as a second stopper 2 32 The material composition is the same as that of the magnetic film, and it can be one of nickel-iron alloy (Ni-Fe alloy), nickel-cobalt alloy (Ni-coalloy), or nickel metal (Ni metal). Magnetic and / one stopper 231 The second stopper 232 is a cushion when the seesaw movement is performed by the same arm 110, and the winter 2/2 is used as a suspension electromagnetic effect to attract the second magnetic film 222, the first stopper f 2. The rotating inductor 21 2 generates a punching pad to prevent the cantilever 11 0 from directly hitting the external strike 2 and the stop state 2 32 can be used as a slow 11 °. The magnetic film and coil mentioned above, and the bottom 320, can protect one group of the cantilever from generating electromagnetic effects. I want two sets of 'can also use the way to improve the reflectivity of the mirror surface, and), and place it at a 45-degree angle with a metal mask (metal mask with high reflectivity as a reflective special metal) on the silicon mirror surface The metal of the electromagnetically driven optical switch, such as gold or aluminum, can be selected. The description is as follows. The process steps of the eight preferred embodiments are detailed into a seesaw unit 100, including the electric wall knife as three parts. One part is shaped like the second magnetic film 22 2 and the first magnetic film in the first moving unit 200 at the same time to form the upper half of the housing 300. 1] stopper 231, second stopper 232, the first part The manufacturing process steps of the parts are shown in Figures A through 8F of the arm, mirror, torsion bar, and diaphragm A, which are schematic diagrams of the manufacturing process of the suspension / stopper. 562951 V. Description of invention (seed la ^ r) Ding'er was formed on the seed layer 820 with a photoresist 830: an opening device ί: shape, as shown in _; continued to plate the recording metal on ί / and remove the photoresist 830 to complete the first magnetic film 221 first magnetic film 222, first stopper 231 and second stopper 23

Production, as shown in Figure 8C. After the processes of the first magnetic film 221, the second magnetic film 222, the first stop, 23 丨 and the second stopper 232 are completed, a photoresist is used to form a cantilever ... The pattern of the torsion bar, as shown in Figure 81); The photoresist is then removed to form a cantilever and a torsion bar, and unwanted seed layers are removed, as shown in FIG. 8E, and the silicon substrate is etched by dry or wet etching, and the photoresist is removed. Finally, a mirror surface is formed on the Shi Xi substrate, and metal is plated on the mirror surface to increase the reflectance. The result is shown in Figure 81 ?. The second part is to form the first spiral inductor 2 ii and the first spiral inductor 222 ′ in the electromagnetic drive unit 2000 and the lower half of the housing 300, which mainly includes three steps, forming a groove, and forming a groove in the groove. Metal is plated to make a planar coil, and finally an electrode is made to complete the coil. First, a recess 920 is formed on a second substrate 910. The process includes: depositing a layer of nitride by low pressure chemical vapor deposition (LPCVD), then applying a photoresist and a pattern of the recess 9 2 0, and etching with reactive ion The nitride layer is dry-etched, the unnecessary photoresist is removed, and finally the wet etching process is performed. The fabrication of the groove 920 is completed, as shown in FIG. 9A. Next, a planar coil 9 3 0 is produced in the groove 9 2 0. The planar coil 9 3 0 includes the following steps: depositing a sub-layer in the groove 92 0, applying a photoresist, and forming a coil pattern, and then electroplating Coated with metal coils and removed at the end

Page 12 562951 V. Description of the Invention (ίο) Photoresist, as shown in Figure 9B. The electrode 940 is finally formed by electricity, and the steps include: photoresist, pole pattern etching of the nitride layer by reactive ion # etching method, and then removing the photoresist, and then performing a wet etching process, and then electroless plating Electroless plating of the electrode completes the electrode manufacturing process, as shown in Figure 9C. The third part is the joining of the upper half and the lower half of the cover 300 to 2 in 2 and 2: i :: The outer cover formed by part of the silicon wafer is precisely aligned: the middle one Λ Λ-the side wall 3 3 0 of the half and the side wall 3 3 of the cover / 4 / is the most / 1 /; the bit groove 410 and the second The positioning groove 420 is placed on the V-shaped groove, and Γ is reused ... sub-fiber 5 °. (― ”In the trench 420 = the upper working 2 = the configuration of the first positioning trench 410 and the second positioning gate of the substrate, as shown in FIG. I0B. Σ together to complete the light opening [effect of the invention] The disclosed electromagnetic private use-torsion bar to increase the production method of the suspension switch, its switching speed, and the straight displacement and restoring force to increase the design of the boat panel shape of the electromagnetic drive 2f, and Cooperate with two effects, increase the function of mirror control, and reduce the crosstalk effect to limit the day of the issue: to: 2: Gui embodiment is disclosed as above, but it is not within the spirit and scope, report; = this similar artist Without departing from the invention, the field can be slightly modified and retouched, so the invention

Page 13 562951 5. The scope of patent protection of the description of invention (11) shall be determined by the scope of patent application attached to this specification. Meeting 1 ^ 1 Page 14 562951 Brief description of the diagrams Figure 1 is the architecture diagram of the conventional optical switch; Figure 2 is the architecture diagram of the conventional optical switch; Figure 3 is the architecture diagram of the conventional optical switch; Figure 4 is A side view of the electromagnetically driven optical switch disclosed in the present invention; FIG. 5 is a top view of the electromagnetically driven optical switch disclosed in the present invention; and FIG. 6 is a three-dimensional structure diagram of the electromagnetically driven optical switch disclosed in the present invention. Fig. 7 is another embodiment of the torsion bar of the electromagnetically driven optical switch disclosed in the present invention; Figs. 8A to 8F are schematic diagrams of the manufacturing process of a cantilever, a mirror, a torsion bar, a magnetic film and a stopper; Figures 9A to 9C are schematic diagrams of the manufacturing process of a spiral suspension inductor; Figure 10A is a schematic diagram of a positioning groove of an electromagnetically driven optical switch disclosed in the present invention; and Figure 10B is a schematic view of the disclosure of the present invention; Schematic diagram of the positioning groove of the electromagnetically driven optical switch. [Illustration of Symbols] 1 〇 A electromagnetic material 1 〇 B electromagnetic material 1 0 C electromagnetic material

1 1 A coil 1 1 B coil 12A magnetic film

Page 15 562951

Schematic description on page 16 12B magnetic film 12C magnetic film 13A cantilever 13B cantilever 13C cantilever 14A mirror 14B mirror 15A optical fiber 100 seesaw unit 110 cantilever 121 first torque lever 122 second torque lever 130 mirror 200 electromagnetic drive unit 211 A spiral inductor 212 --- spiral inductor 221 first magnetic film 222 second magnetic film 231 first stopper 232 first-stopper 241 first groove 242 first-groove 300 cover 310 side wall 562951 diagram simple illustration 320 bottom 330 sidewall 340 sidewall 410 first positioning groove 420 second positioning groove 500 dummy fiber 810 first silicon substrate 820 seed layer 830 photoresist 840 photoresist 910 second substrate 920 groove 930 plane coil 940 electrode

Page 17

Claims (1)

562951 VI. Scope of patent application: An electromagnetically driven optical switch includes: a cantilever, which is a sheet-like structure; a torsion bar, located on both sides of the longer end of the cantilever; a mirror surface, formed on the cantilever One side; a planar coil formed in a groove at the bottom of the cover; and a magnetic film formed below the cantilever, opposite to the planar coil; ♦ Where a magnetic force is generated by the planar coil to attract the When the magnetic film is driven, the cantilever is driven to make a vertical displacement to make the mirror block the light beam from passing, and when the magnetic force of the plane coil disappears, the cantilever is restored to the original position by a restoring force generated by the torsion bar. 2. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, which further includes a stopper formed on the outer side of the magnetic film at the lower end of the cantilever, and used as a cushion when the cantilever is vertically displaced. 3. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, wherein the cantilever and the torsion bar are integrally formed. 4. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, wherein the cantilever is completed by dry etching a silicon wafer. 5. The electromagnetically driven optical switch as described in item 1 of the scope of the patent application, wherein the cantilever is completed with a wet-cut stone chip. 6. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, wherein the planar coil is made by electroplating. 7. The electromagnetically driven optical switch as described in item 1 of the patent application scope, wherein Page 18 562951 VI. Scope of patent application The material of the plane coil is selected from any combination of gold and copper. 8. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, wherein the groove is achieved by dry or wet etching. 9. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, wherein the planar coil is plated in the groove. 10. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, wherein the magnetic film is completed by electroplating. 11. The electromagnetically driven optical switch according to item 1 of the scope of the patent application, wherein the material of the magnetic film is any one selected from the group consisting of nickel-iron alloy, nickel-cobalt alloy, and nickel metal. 1 2. The electromagnetically driven optical switch as described in item 2 of the scope of patent application, wherein the material of the stopper is selected from the group consisting of nickel-iron alloy, nickel alloy and nickel metal. 1 3. The electromagnetically driven optical switch as described in item 2 of the scope of patent application, wherein the magnetic film and the stopper are completed in the same process step. 14. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, wherein the mirror surface is a metal mask, and a metal key is placed on the stone evening mirror surface at an angle of 45 degrees. 15. The electromagnetically driven optical switch as described in item 1 of the scope of patent application, wherein the metal plated on the mirror surface is selected from any combination of gold and aluminum. 16. A method for manufacturing an electromagnetically driven optical switch, comprising the following steps: providing a first substrate; and sequentially forming a magnetic film, a stopper, and a first substrate on the first substrate; Page 19 562951 VI. Patent application scope Cantilever, a torsion bar, and a mirror surface; providing a second substrate; forming a groove on the second substrate, and forming a planar coil in the groove; and The first substrate and the second substrate are pressed together to complete the structure of the optical switch. 17. The method for manufacturing an electromagnetically driven optical switch as described in item 16 of the scope of patent application, wherein in the step of pressing the first substrate and the second substrate, one of the first substrate and the second substrate is used. A positioning groove and a gap formed in a second positioning groove in the second substrate place a dummy optical fiber in the positioning groove, so that the first substrate and the second substrate can be accurately aligned and bonded. 18. The manufacturing method of the electromagnetically driven optical switch as described in item 17 of the scope of patent application, wherein the positioning groove is a V-shaped groove. 19. The method for manufacturing an electromagnetically driven optical switch as described in item 16 of the scope of patent application, wherein the magnetic film and the stopper are completed in the same process step. 20. The manufacturing method of the electromagnetically driven optical switch as described in item 16 of the scope of patent application, wherein the cantilever and the torque rod are completed in the same process step.