CN116679443A - Micro-mirror structure adopting movable support and manufacturing method - Google Patents

Abstract

The invention discloses a micro-mirror structure adopting movable support and a manufacturing method, wherein the micro-mirror structure comprises: the micro-bridge structure comprises a support and electric connecting column and a micro-bridge deck movably supported on the support and electric connecting column; the micro-bridge deck is provided with a micro-mirror surface, an electric connection is formed between the micro-mirror surface and the supporting and electric connecting column, the supporting and electric connecting column is electrically connected with the substrate, and when the micro-mirror surface is driven, the micro-bridge deck is driven to deflect around a movable supporting position on the supporting and electric connecting column. The invention can obviously reduce the actuation voltage of the micromirror and reduce the working voltage of the device.

Description

Micro-mirror structure adopting movable support and manufacturing method

Technical Field

The present invention relates to the field of micro-electromechanical systems (MEMS), and more particularly, to a micro-mirror structure using movable supports and a method of manufacturing the same.

Background

MEMS micromirrors are a hotspot product in MEMS products, which are widely used, including optical communications, 3D cameras, projectors, etc. In recent years, in particular, MEMS micro-mirrors have become an important component in vehicle-mounted laser radars, and with development of autopilot technology, market demands for MEMS micro-mirrors are increasing, and higher demands are also put on technologies thereof.

The MEMS micromirror support structure generally adopts a double-end fixed support torsion arm (finger) structure, and generally uses an electrostatic driving mode to drive the micromirror to rotate around the torsion arm, so as to control the deflection angle of the micromirror. However, since the two ends of the torsion arm are fixedly supported on the support column, when the electrostatic driver is adopted to drive the mirror surface of the micromirror to deflect, the rigidity of the torsion arm structure needs to be overcome, which leads to higher actuation voltage of the micromirror and higher working voltage of the device.

Disclosure of Invention

The present invention is directed to overcoming the above-mentioned drawbacks of the prior art and providing a micromirror structure employing a movable support and a method of manufacturing the same.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

the invention provides a micromirror structure using movable support, comprising:

the micro-bridge structure comprises a support and electric connecting column and a micro-bridge deck movably supported on the support and electric connecting column; the micro-bridge deck is provided with a micro-mirror surface, an electric connection is formed between the micro-mirror surface and the supporting and electric connecting column, the supporting and electric connecting column is electrically connected with the substrate, and when the micro-mirror surface is driven, the micro-bridge deck is driven to deflect around a movable supporting position on the supporting and electric connecting column.

Further, the number of the supporting and electric connecting columns is two, the supporting and electric connecting columns are provided with conductive shaft sleeves, the bridge deck of the micro-bridge is connected to the side surfaces of the conductive torsion arms, the torsion arms penetrate through the two ends to form movable supporting coordination in the shaft sleeves of the supporting and electric connecting columns, and the micro-mirror surface is electrically connected with the substrate through the torsion arms, the shaft sleeves and the supporting and electric connecting columns.

Further, the micro bridge deck comprises a first sub micro bridge deck and a second sub micro bridge deck, the first sub micro bridge deck and the second sub micro bridge deck are arranged in a coplanar manner and are respectively connected to two sides of the torsion arm, a first sub micro mirror surface is arranged on the first sub micro bridge deck, and a second sub micro mirror surface is arranged on the second sub micro bridge deck.

Further, addressing electrodes are correspondingly arranged on the substrate below the first sub-micro mirror surface and the second sub-micro mirror surface.

Further, the two ends of the torsion arm are provided with supporting parts, the shaft sleeve is provided with shaft holes, the two ends of the torsion arm are supported on the bottom of the shaft holes through the supporting parts, and when the micromirror mirror surface is driven, the microbridge deck is driven to deflect by taking the supporting parts as fulcrums.

Further, the support portion has a rectangular, tapered or arcuate cross section.

Further, the supporting and electric connecting column is formed in a groove, the groove is arranged in a sacrificial layer, the sacrificial layer is positioned between the substrate and the micro-bridge deck, the supporting and electric connecting column comprises a conductor formed on part of the side wall surface of the groove and a supporting body positioned on the inner side of the conductor, the micro-bridge deck is movably supported on the supporting body and the conductor, the micro-mirror surface is electrically connected with the substrate through the conductor, and the micro-bridge structure is released through removing the sacrificial layer; the micro-mirror structures are arranged on the substrate in a row-column mode to form an array, and the same supporting and electric connecting column is shared between any two adjacent micro-mirror structures in the same row or the same column, or the supporting and electric connecting columns of any two adjacent micro-mirror structures in the same row or the same column are arranged close to each other and are formed on the side walls of the opposite sides of the same groove.

The invention also provides a method for manufacturing the micro-mirror structure by adopting the movable support, which comprises the following steps:

providing a substrate;

forming a sacrificial layer on the substrate, forming two supporting and electric connecting columns on the substrate in the sacrificial layer, a conductive shaft sleeve on each supporting and electric connecting column, conductive torsion arms penetrating through the two shaft sleeves at two ends and keeping a space, and a micromirror surface connected to the side surface of the torsion arm;

and removing the sacrificial layer, so that the torsion arm and the micromirror mirror connected with the torsion arm fall on the shaft sleeve, and the micromirror mirror is movably supported on the support and the electric connecting column through the movable fit between the two ends of the torsion arm and the shaft sleeve.

Further, the method for forming a sacrificial layer on the substrate, forming two support and electric connection posts on the substrate in the sacrificial layer, and a conductive sleeve on each support and electric connection post, conductive torsion arms penetrating through the two sleeves at two ends and keeping a distance, and a micromirror surface connected to the side surface of the torsion arm, specifically comprises:

forming a first sacrificial layer on the surface of the substrate;

forming two trenches on the first sacrificial layer surface and stopping on the substrate surface;

forming one of the support and electrical connection posts in each of the trenches;

forming a shaft sleeve bottom pattern on the top surface of each supporting and electric connecting column;

forming a second sacrificial layer on the surface of the first sacrificial layer, and covering the bottom graph of the shaft sleeve;

forming the torsion arm and the micromirror surfaces connected to the two sides of the torsion arm on the surface of the second sacrificial layer, and enabling the two ends of the torsion arm to be respectively positioned above the bottom patterns of the two shaft sleeves;

forming a third sacrificial layer on the surface of the second sacrificial layer, and covering the torsion arm and the micromirror surface;

forming two pairs of through holes on the surface of the third sacrificial layer, wherein each pair of through holes are positioned on two sides of the torsion arm and stop on the pattern surface at the bottom of the shaft sleeve;

forming a shaft sleeve side part pattern with the lower end connected with the shaft sleeve bottom pattern in each pair of through holes, and forming two shaft sleeve top patterns respectively connected with the upper ends of each pair of shaft sleeve side part patterns on the surface of the third sacrificial layer, thereby forming the shaft sleeve on the top surface of the supporting and electric connecting column, and enabling the two ends of the torsion arm to penetrate into the two shaft sleeves at a certain interval;

the sacrificial layer is removed, so that the torsion arm and the micromirror mirror connected with the torsion arm fall on the shaft sleeve, and the micromirror mirror is movably supported on the support and the electric connection column through the movable fit between the two ends of the torsion arm and the shaft sleeve, and the method specifically comprises the following steps:

and removing the first sacrificial layer to the third sacrificial layer, so that the torsion arm and the micromirror surface connected with the torsion arm naturally fall under the action of gravity until the two ends of the torsion arm fall on the pattern surface at the bottom of the shaft sleeve to obtain support, and the torsion arm and the shaft sleeve form movable fit through the two ends, so that the micromirror surface is movably supported on the support and the electric connecting column.

Further, the forming the torsion arm on the surface of the second sacrificial layer, and the micromirror mirrors connected to two sides of the torsion arm, and making two ends of the torsion arm respectively located above two patterns at the bottom of the shaft sleeve specifically includes:

forming grooves on the surface of the second sacrificial layer, and enabling two ends of the grooves to be respectively positioned above the bottom patterns of the two shaft sleeves;

forming a micromirror metal layer on the surface of the second sacrificial layer, and filling the grooves to form a supporting part in the grooves;

patterning the micromirror metal layer, further forming the torsion arm on the supporting part, and connecting the micromirror mirror surfaces on two sides of the torsion arm, so that two ends of the torsion arm are respectively positioned above the two shaft sleeve bottom patterns;

after the first sacrificial layer is removed to the third sacrificial layer, the torsion arm is supported by the pattern surface of the bottom of the shaft sleeve, and is in movable fit with the shaft sleeve through the supporting part.

According to the technical scheme, the fixed connection mode between the conventional micro mirror surface and the support column is improved, and the micro mirror surface can deflect around the movable support on the support and the electric connection column by movably supporting the micro mirror surface on the support and the electric connection column, so that a teeterboard structure is formed; therefore, when the micromirror surface is deflected by electrostatic drive, the rigidity of the torsion arm structure is not needed to be overcome, and the micromirror surface (the microbridge deck) can be rotated around a movable rotating shaft formed by the torsion arm, so that the actuation voltage of the micromirror can be remarkably reduced, and the working voltage of the device is reduced.

Drawings

FIGS. 1-3 are schematic views of a micromirror structure using movable supports according to a preferred embodiment of the invention;

fig. 4-6 are schematic views showing a fitting structure of a shaft sleeve and a supporting portion according to a preferred embodiment of the present invention;

FIGS. 7-12 are schematic views illustrating steps of a method for fabricating a micromirror structure using movable support according to a first preferred embodiment of the invention;

FIGS. 13-19 are schematic views illustrating steps of a method for fabricating a micromirror structure using movable support according to a second preferred embodiment of the invention;

fig. 20-26 are schematic views showing the steps of a method for fabricating a micromirror structure using movable support according to a third preferred embodiment of the invention.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. Unless otherwise defined, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. As used herein, the word "comprising" and the like means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof without precluding other elements or items.

The following describes the embodiments of the present invention in further detail with reference to the accompanying drawings.

Referring to fig. 1-3, fig. 1-3 are schematic views of a micromirror structure with movable support according to a preferred embodiment of the invention. Fig. 2 is a right-side structural view of fig. 1, and fig. 3 is a top-side structural view of fig. 1. As shown in fig. 1 to 3, a micromirror structure using movable support according to the present invention comprises: a micro-bridge structure provided on the substrate 10. The micro-bridge structure comprises a supporting and electric connecting column 13 and a micro-bridge deck 20 movably supported on the supporting and electric connecting column 13. The micro bridge deck 20 is provided with a micro mirror 12 (mirror layer), and an electrical connection is formed between the micro mirror 12 and the support and electrical connection post 13, and the support and electrical connection post 13 is electrically connected to the substrate 10, so that the micro mirror 12 is electrically connected to the substrate 10 through the support and electrical connection post 13. Thus, when the micromirror mirror 12 is driven, the micromirror bridge 20 is driven to deflect up and down around the movable support (torsion arm 14/support 141) on the support and electrical connection post 13, so that the micromirror mirror 12 (micromirror bridge 20) forms a seesaw-like structure on the support and electrical connection post 13.

In some embodiments, the support and electrical connection posts 13 may be two and may be juxtaposed on the surface of the substrate 10, as shown in fig. 2.

Further, a conductive bushing 15 with a shaft hole 154 may be provided on the support and electrical connection post 13, for example, on the top surface of the support and electrical connection post 13, as shown in fig. 1.

A conductive torsion arm 14 (finger) can be provided between the sleeves 15 of the two support and electrical connection posts 13. Microbridge deck 20 (micromirror mirror 12) may be attached to the side of conductive torsion arm 14 and supported. The torsion arm 14 is penetrated into the shaft holes 154 of the two shaft sleeves 15 through two ends, and forms movable supporting fit with the shaft sleeves 15, namely the supporting and electric connecting posts 13. The micromirror mirror surface 12 is tiled on the microbridge deck 20 to form an electrical connection with the torsion arm 14, and the torsion arm 14 is in contact with the inner wall of the shaft hole 154 of the shaft sleeve 15 at both ends to form an electrical connection. Thus, micromirror mirror 12 is electrically connected to substrate 10 through torsion arm 14, bushing 15, and support and electrical connection posts 13.

In some embodiments, the microbridge deck 20 may include a first sub-microbridge deck and a second sub-microbridge deck. The first sub-bridge deck and the second sub-bridge deck may be arranged coplanar and connected on both sides of the torsion arm 14, respectively. The first sub-micro bridge deck may be provided with a first sub-micro mirror surface, the second sub-micro bridge deck may be provided with a second sub-micro mirror surface, and the first sub-micro mirror surface and the second sub-micro mirror surface together form a micro mirror surface 12.

In some embodiments, the addressing electrode 11 of the electrostatic driver can be correspondingly arranged on the substrate 10 below the first sub-micromirror mirror surface and the second sub-micromirror mirror surface, and a capacitance structure is formed between the addressing electrode and the micromirror mirror surface 12, so that the electrostatic driver can be used to drive the micromirror mirror surface 12 to rotate (deflect) on the support and electric connection post 13 around the movable rotation shaft formed by the torsion arm 14, and the rigidity of the torsion arm 14 structure can not be overcome, so that the actuation voltage of the micromirror can be remarkably reduced, and the working voltage of the device can be reduced.

In some embodiments, both ends of torque arm 14 may be utilized directly as support portions and may be supported on the bottom of shaft bore 154 of sleeve 15, as shown in FIG. 3. When the micromirror face 12 is driven, the micromirror deck 20 is driven to deflect about the two ends (supports) of the torsion arm 14.

Please refer to fig. 4-6. In some embodiments, support portions 141 may be additionally provided on both ends of the torsion arm 14. The supporting portion 141 may have, for example, a rectangular shape as shown in fig. 4, a tapered shape as shown in fig. 5, or an arc-shaped cross section as shown in fig. 6, but is not limited thereto. Both ends of the torsion arm 14 may be supported on the bottom of the shaft hole 154 by the lower ends of the supporting portions 141. When the micromirror plate 12 is driven, the bridge deck 20 is driven to deflect about the supporting point (supporting point) where the lower end of the supporting portion 141 contacts the bottom of the shaft hole 154.

The support portions 141 may be provided only at both ends of the torsion arm 14, or may be provided on the entire lower surface of the torsion arm 14 in the longitudinal direction of the torsion arm 14, and may be integrally formed with the torsion arm 14. Alternatively, the torsion arm 14 may be formed entirely using the shape of the supporting portion 141.

In some embodiments, the shaft aperture 154 may have any cross-sectional shape that is capable of forming a clearance fit with the ends of the torque arm 14, such as circular, semi-circular, elliptical, semi-elliptical, polygonal, etc. The illustration is merely a form of construction of the rectangular shaft bore 154 (rectangular boss 15) that is relatively easy to implement using semiconductor processing, and should not be construed as limiting the construction of the shaft bore 154 and boss 15 of the present invention.

In some embodiments, the support and electrical connection post 13 may be provided with an electrical conductor and a support body, and the sleeve 15 may be provided on top of the electrical conductor and support body and form an electrical connection with the electrical conductor.

In some embodiments, a metal connection structure (not shown) may be provided on the surface of the substrate 10; the metal connection structure electrically connects the substrate 10. The support and electrical connection posts 13 may be disposed on the metal connection structure and form an electrical connection with the metal connection structure. So that the micromirror mirror 12 can be electrically connected to the substrate 10 through the support and electrical connection posts 13, the metal connection structure.

In some embodiments, the substrate 10 may be a conventional semiconductor substrate 10, such as a silicon substrate 10, or may be a transparent material substrate 10, such as glass, and circuit structures for forming CMOS devices, electrostatic controllers, and the like may be fabricated on the substrate 10.

In some embodiments, the conductive materials in the micromirror mirror 12, the torsion arm 14 (including the support 141), the bushing 15, and the support and electrical connection post 13 may be conductive materials such as metal.

In some embodiments, the micromirror mirror 12, torsion arm 14, bushing 15, and electrical conductor materials may be the same or different.

In some embodiments, the micromirror mirror 12, torsion arm 14, bushing 15, and/or the conductive material may be at least one of aluminum (Al), platinum (Pt), gold (Au), silver (Ag), and metal alloys thereof.

In some embodiments, the support and electrical connectionThe support material in the stud 13 may be a dielectric material, such as SiO ₂ At least one of SiN, siON, siC, etc.

In some embodiments, the address electrode 11 and the metal connection structure may be made of a conductive material such as metal. For example, the address electrode 11, the metal connection structure material may employ at least one of aluminum, platinum, gold, silver, etc., and a metal alloy, etc.

In other embodiments, the support and electrical connection posts 13 may be formed in trenches, which may be provided in the sacrificial layer 16 (which may include the first sacrificial layer 161, the second sacrificial layer 162, the third sacrificial layer 163), the sacrificial layer 16 being located between the substrate 10 and the microbridge deck 20 (refer to fig. 7-12). The support and electrical connection post 13 may include an electrical conductor disposed longitudinally along the sidewall of the trench and formed on a portion of the sidewall surface of the trench, and a support body located inside the electrical conductor. The sleeve 15 is positioned on the top surface of the support and the conductor, and the micromirror mirror surface 12 (the microbridge surface 20) is movably supported on the support and the conductor by two ends of the torsion arm 14 inserted into the shaft hole 154 of the sleeve 15. Thus, the micromirror mirror 12 is electrically connected to the substrate 10 through the electrical conductor. The sacrificial layer 16 is removed after formation of the microbridge structure, allowing the micromirror mirror surface 12 (microbridge deck 20) to be released and controlled for deflection movement. In this embodiment, since the supporting and electrical connection posts 13 occupy only a part of the area of the trench, the occupied area of the formed supporting and electrical connection posts 13 in the micromirror can be reduced, so that the area of the micromirror surface 12 can be effectively increased, and the filling factor and the product performance can be greatly improved. Further, the micromirror structures may be arranged in rows and columns on the substrate 10 and form micromirror arrays. The same support and electrical connection post 13 may be shared between any two adjacent micromirror structures (microbridge structures) that are in the same row or column. Alternatively, the respective support and electrical connection posts 13 of any two adjacent micromirror structures in the same row or column are disposed adjacent to each other and formed on the side walls of the same trench on opposite sides. Thus, the filling factor of the micromirror array is also significantly improved.

In some embodiments, the sacrificial layer 16 material may be a dielectric material or the like that has a high etch selectivity with respect to the substrate 10 and the microbridge structure when the release process is performed. For example, amorphous silicon, polymer, polyimide, polysilicon, silicon nitride, silicon dioxide, or the like may be used as the material of the sacrificial layer 16.

A method for manufacturing a micromirror structure using a movable support according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to fig. 7-12, fig. 7-12 are schematic views illustrating steps of a method for fabricating a micromirror structure using movable support according to a first preferred embodiment of the invention. As shown in fig. 7 to 12, a method for manufacturing a micromirror structure using movable support according to the present invention can be used to manufacture a micromirror structure using both ends of torsion arm 14 as supporting parts 141 directly in fig. 1 to 3, for example, and can include the following steps:

please refer to fig. 7. First, one semiconductor substrate 10, for example, a silicon substrate 10, may be used, and a CMOS front-end device required for forming MEMS, a circuit structure required for an electrostatic driver, and the like may be fabricated on the substrate 10.

Then, a first metal layer may be formed on the surface of the substrate 10 using, for example, a metal deposition process or the like, and patterned using photolithography and etching processes to form two patterns of address electrodes 11. The first metal layer material may be, for example, metallic aluminum or the like.

Next, a first sacrificial layer 161 may be deposited on the surface of the substrate 10 using, for example, a dielectric deposition process or the like, and the address electrode 11 is covered. The material of the first sacrificial layer 161 may be polyimide, for example.

Next, two trenches may be formed on the surface of the first sacrificial layer 161 using photolithography and etching processes, stopping on the surface of the substrate 10, and the two trenches may be located between the two address electrodes 11, and a center line of the two trenches may be orthogonal to a center line of the two address electrodes 11.

Thereafter, a second metal layer may be conformally formed on the inner walls of the trench using, for example, a conformal deposition process or the like. The second metal layer material may be, for example, metallic aluminum or the like. The trench may then be filled with a further support layer in the trench within the second metal layer, using for example a dielectric deposition process or the like. The support layer material may be, for example, silicon nitride or the like.

Next, the structure surface after the above steps may be planarized, for example, by a Chemical Mechanical Polishing (CMP) process, to remove the excess second metal layer material and the support layer material on the surface of the first sacrificial layer 161 outside the trenches, thereby forming one support and electrical connection post 13 in each trench. The support and electrical connection post 13 includes an electrical conductor formed of a second metal layer material, and a support body formed of a support layer material.

Then, a third metal layer may be formed on the surface of the first sacrificial layer 161 using, for example, a metal deposition process or the like, and patterned using a photolithography and etching process, and a sleeve bottom pattern 151 may be formed on the top surface of each support and electrical connection post 13. The third metal layer material may be, for example, metallic aluminum or the like.

Please refer to fig. 8. Next, a second sacrificial layer 162 may be deposited on the surface of the first sacrificial layer 161 using, for example, a dielectric deposition process or the like, and the sleeve bottom pattern 151 is covered. The second sacrificial layer 162 may be made of polyimide, for example.

Then, a micromirror metal layer may be formed on the surface of the second sacrificial layer 162 using, for example, a metal deposition process or the like, the sleeve bottom pattern 151 is covered, and patterning may be performed using photolithography and etching processes, the torsion arm 14 and the micromirror mirrors 12 (first sub-micromirror mirror and second sub-micromirror mirror) connected on both sides of the torsion arm 14 are formed on the surface of the second sacrificial layer 162, and both ends of the torsion arm 14 are respectively located above the two sleeve bottom patterns 151. Thereby forming a microbridge deck 20 structure. The micromirror metal layer material may be, for example, metallic aluminum or the like.

Please refer to fig. 9. Next, a third sacrificial layer 163 may be deposited on the surface of second sacrificial layer 162, using, for example, a dielectric deposition process, etc., to cover microbridge deck 20 including micromirror mirror 12, torsion bar 14. The material of the third sacrificial layer 163 may be polyimide, for example. The first to third sacrificial layers 161 to 163 collectively form a sacrificial layer 16 structure.

Then, two pairs of through holes may be formed on the surface of the third sacrificial layer 163 using, for example, photolithography and etching processes, such that each pair of through holes is located on both sides of the torsion arm 14 and stopped on the surface of the sleeve bottom pattern 151.

Next, a fourth metal layer may be filled in each pair of through holes and planarized using, for example, a through hole filling process, and a sleeve side pattern 152 having a lower end connected to the sleeve bottom pattern 151 may be formed in each pair of through holes. The fourth metal layer material may be, for example, metallic aluminum or the like.

Please refer to fig. 10. Then, a fifth metal layer may be formed on the surface of the third sacrificial layer 163 using, for example, a metal deposition process or the like, and patterning may be performed using photolithography and etching processes, and two sleeve top patterns 153 connected to the upper ends of each pair of sleeve side patterns 152 are formed on the surface of the third sacrificial layer 163, thereby forming a ring-shaped sleeve 15 on the top surface of the support and electrical connection post 13, and allowing both ends of the torsion arm 14 to be penetrated into the two sleeves 15 with a maintained interval by the isolation of the second sacrificial layer 162 and the third sacrificial layer 163. The fifth metal layer material may be, for example, metallic aluminum or the like, thereby forming an aluminum metal sleeve 15.

Please refer to fig. 11-12. Thereafter, the micro mirror surface 12 (micro bridge deck 20) can be released by removing all the sacrificial layers 16 including the first to third sacrificial layers 161 to 163 through an etching process (release process) and utilizing a high etching selectivity of the first to third sacrificial layers 161 to 163 with respect to other structural materials. At this time, due to the removal of the sacrificial layer 16, the torsion arm 14 and the micromirror 12 connected with the torsion arm are naturally dropped under the action of gravity due to the loss of the support of the sacrificial layer 16 until the two ends of the torsion arm 14 fall on the surface of the bottom pattern 151 of the shaft sleeve 15 to obtain the support, so that the torsion arm 14 forms a movable fit with the shaft sleeve 15 through the two ends, and the micromirror 12 is movably supported on the support and electrical connection post 13.

When the micro mirror 12 is driven by the addressing electrode 11, the two ends of the torsion arm 14 are used as supporting parts, and the supporting points of the supporting parts can deflect along with the deflection of the micro mirror 12 on the bottom surface of the shaft hole 154 of the shaft sleeve 15, so that the problem that the rigidity of the torsion arm 14 needs to be overcome when the micro mirror 12 deflects is effectively solved.

Referring to fig. 13-19, fig. 13-19 are schematic views illustrating steps of a method for fabricating a micro-mirror structure using movable support according to a second preferred embodiment of the invention. As shown in fig. 13 to 19, a method for manufacturing a micromirror structure using a movable support according to the present invention can be used to manufacture a micromirror structure having a torsion arm 14 with a rectangular support 141 of fig. 4 and realizing movable support, and can include the steps of:

please refer to fig. 13. First, the address electrode 11 may be formed on the substrate 10, the first sacrificial layer 161 may be deposited on the surface of the substrate 10, two grooves may be formed on the surface of the first sacrificial layer 161, the support and electrical connection posts 13 may be formed in the grooves, the sleeve bottom pattern 151 may be formed on the top surface of the support and electrical connection posts 13, the second sacrificial layer 162 covering the sleeve bottom pattern 151 may be formed on the surface of the first sacrificial layer 161, and the like, in the same or similar manner as the above-described embodiment.

Then, two grooves may be formed on the surface of the second sacrificial layer 162 using, for example, photolithography and anisotropic etching processes, such that the two grooves are respectively located above one of the sleeve bottom patterns 151 and do not contact the sleeve bottom patterns 151. The recess formed may have, for example, a rectangular cross section.

Next, the groove may be filled with, for example, aluminum metal and planarized, and a support portion 141 having a rectangular cross section is formed in the groove.

Please refer to fig. 14. Next, a micromirror metal layer may be deposited on the surface of the second sacrificial layer 162 and the surface of the supporting portion 141 using, for example, a metal deposition process, etc., the sleeve bottom pattern 151 may be covered, and patterning may be performed using photolithography and etching processes, the torsion arm 14 may be formed on the surface of the second sacrificial layer 162, and the micromirror mirrors 12 (the first sub-micromirror mirror and the second sub-micromirror mirror) connected to both sides of the torsion arm 14 may be formed, and both lower surfaces of the torsion arm 14 may be connected to the upper surfaces of the supporting portions 141 located above the two sleeve bottom patterns 151, respectively. Thereby forming a microbridge deck 20 structure. The micromirror metal layer material may be, for example, metallic aluminum or the like.

Please refer to fig. 15. Next, a third sacrificial layer 163 may be deposited on the surface of second sacrificial layer 162, using, for example, a dielectric deposition process, etc., to cover microbridge deck 20 including micromirror mirror 12, torsion bar 14. The material of the third sacrificial layer 163 may be polyimide, for example.

Please refer to fig. 16. Then, two pairs of through holes may be formed on the surface of the third sacrificial layer 163 using, for example, photolithography and etching processes, such that each pair of through holes is located on both sides of the torsion arm 14 and stopped on the surface of the sleeve bottom pattern 151.

Next, a fourth metal layer may be filled in each pair of through holes and planarized using, for example, a through hole filling process, and a sleeve side pattern 152 having a lower end connected to the sleeve bottom pattern 151 may be formed in each pair of through holes. The fourth metal layer material may be, for example, metallic aluminum or the like.

Please refer to fig. 17. Then, a fifth metal layer may be formed on the surface of the third sacrificial layer 163 using, for example, a metal deposition process or the like, and patterning may be performed using photolithography and etching processes, and two sleeve top patterns 153 connected to the upper ends of each pair of sleeve side patterns 152 are formed on the surface of the third sacrificial layer 163, thereby forming a ring-shaped sleeve 15 on the top surface of the support and electrical connection post 13, and allowing both ends of the torsion arm 14 having the support portion 141 to be penetrated into the two sleeves 15 with a maintained interval by the isolation of the second sacrificial layer 162 and the third sacrificial layer 163. The fifth metal layer material may be, for example, metallic aluminum or the like, thereby forming an aluminum metal sleeve 15.

Please refer to fig. 18-19. After that, the first to third sacrificial layers 161 to 163 are removed by an etching process (a releasing process) so that the torsion arm 14 and the micromirror 12 connected thereto naturally drop until the supporting portions 141 at both ends of the torsion arm 14 fall on the surface of the bottom pattern 151 of the shaft sleeve 15, so that the entire micro bridge deck 20 is supported, thereby enabling the torsion arm 14 to form a movable fit with the shaft sleeve 15 through the supporting portions 141 at both ends and enabling the micromirror 12 to be movably supported on the supporting and electrical connection post 13.

Referring to fig. 20-26, fig. 20-26 are schematic views illustrating steps of a method for fabricating a micromirror structure using movable support according to a third preferred embodiment of the invention. As shown in fig. 20 to 26, a method for manufacturing a micromirror structure using a movable support according to the present invention can be used to manufacture a micromirror structure having a torsion arm 14 with an arc-shaped support 141 of fig. 6 and realizing a movable support, and can include the steps of:

please refer to fig. 20. First, the address electrode 11 may be formed on the substrate 10, the first sacrificial layer 161 may be deposited on the surface of the substrate 10, two grooves may be formed on the surface of the first sacrificial layer 161, the support and electrical connection posts 13 may be formed in the grooves, the sleeve bottom pattern 151 may be formed on the top surface of the support and electrical connection posts 13, the second sacrificial layer 162 covering the sleeve bottom pattern 151 may be formed on the surface of the first sacrificial layer 161, and the like, in the same or similar manner as the above-described embodiment.

Then, grooves 17 may be formed on the surface of the second sacrificial layer 162 using, for example, photolithography and isotropic etching processes, such that both ends of the grooves 17 in the length direction are respectively located above one of the sleeve bottom patterns 151, and are not in contact with the sleeve bottom patterns 151. The recess 17 may be formed with a cross-section such as an arc (or approximately an inverted cone).

Please refer to fig. 21. Next, a micromirror metal layer may be formed on the surface of the second sacrificial layer 162 using, for example, a metal deposition process, etc., the sleeve bottom pattern 151 is covered, and the groove 17 is filled with a micromirror metal layer material, and the support portion 141 having an arc-shaped cross section may be formed using the micromirror metal layer material portion filled in the groove 17.

Next, the micromirror metal layer may be patterned using photolithography and etching processes, the torsion arm 14 is further formed in a complete shape on the basis of the arc-shaped supporting parts 141, and the micromirror surfaces 12 (the first sub-micromirror surface and the second sub-micromirror surface) connected on both sides of the torsion arm 14 are formed on the surface of the second sacrificial layer 162. Thereby forming a microbridge deck 20 structure. The micromirror metal layer material may be, for example, metallic aluminum or the like.

In this embodiment, the torsion arm 14 may be directly formed by using the arc-shaped supporting portion 141.

Please refer to fig. 22. Next, a third sacrificial layer 163 may be deposited on the surface of second sacrificial layer 162, using, for example, a dielectric deposition process, etc., to cover microbridge deck 20 including micromirror mirror 12, torsion bar 14. The material of the third sacrificial layer 163 may be polyimide, for example.

Please refer to fig. 23. Then, two pairs of through holes may be formed on the surface of the third sacrificial layer 163 using, for example, photolithography and etching processes, such that each pair of through holes is located on both sides of the torsion arm 14 and stopped on the surface of the sleeve bottom pattern 151.

Next, a fourth metal layer may be filled in each pair of through holes and planarized using, for example, a through hole filling process, and a sleeve side pattern 152 having a lower end connected to the sleeve bottom pattern 151 may be formed in each pair of through holes. The fourth metal layer material may be, for example, metallic aluminum or the like.

Please refer to fig. 24. Then, a fifth metal layer may be formed on the surface of the third sacrificial layer 163 using, for example, a metal deposition process or the like, and patterning may be performed using photolithography and etching processes, and two sleeve top patterns 153 connected to the upper ends of each pair of sleeve side patterns 152, respectively, are formed on the surface of the third sacrificial layer 163, thereby forming a ring-shaped sleeve 15 on the top surface of the support and electrical connection post 13, and allowing both ends of the torsion arm 14 having the arc-shaped support portion 141 to be penetrated into the two sleeves 15 with a maintained interval by the isolation of the second sacrificial layer 162 and the third sacrificial layer 163. The fifth metal layer material may be, for example, metallic aluminum or the like, thereby forming an aluminum metal sleeve 15.

Please refer to fig. 25-26. After that, the first to third sacrificial layers 161 to 163 are removed by an etching process (a releasing process) so that the torsion arm 14 and the micromirror 12 connected thereto naturally drop until the supporting portions 141 at both ends of the torsion arm 14 fall on the surface of the bottom pattern 151 of the shaft sleeve 15, so that the entire micro bridge deck 20 is supported, thereby enabling the torsion arm 14 to form a movable fit with the shaft sleeve 15 through the supporting portions 141 at both ends and enabling the micromirror 12 to be movably supported on the supporting and electrical connection post 13.

In summary, the invention improves the prior fixed connection mode between the micromirror mirror surface and the support column, and adopts a mode of movably supporting the micromirror mirror surface 12 on the support and electric connection column 13 through the shaft sleeve 15, so that the micromirror mirror surface 12 can deflect around the movable support on the support and electric connection column 13 to form a teeterboard structure; thus, when the micromirror face 12 is deflected by, for example, electrostatic driving, the rigidity of the torsion arm 14 structure is not required to be overcome as in the prior art, but the micromirror face 12 (the microbridge deck 20) can be deflected around the movable rotation shaft formed by the torsion arm 14, so that the actuation voltage of the micromirror can be significantly reduced, and the operating voltage of the device can be reduced.

While embodiments of the present invention have been described in detail hereinabove, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. It is to be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the following claims. Moreover, the invention described herein is capable of other embodiments and of being practiced or of being carried out in various ways.

Claims (10)

1. A micromirror structure using movable support, comprising:

the micro-bridge structure comprises a support and electric connecting column and a micro-bridge deck movably supported on the support and electric connecting column; the micro-bridge deck is provided with a micro-mirror surface, an electric connection is formed between the micro-mirror surface and the supporting and electric connecting column, the supporting and electric connecting column is electrically connected with the substrate, and when the micro-mirror surface is driven, the micro-bridge deck is driven to deflect around a movable supporting position on the supporting and electric connecting column.

2. The micro-mirror structure with movable support according to claim 1, wherein the number of the support and electric connection columns is two, the support and electric connection columns are provided with conductive shaft sleeves, the bridge deck of the micro-bridge is connected to the side surfaces of the conductive torsion arms, the torsion arms penetrate through the shaft sleeves of the two support and electric connection columns through two ends to form movable support coordination, and the micro-mirror surface is electrically connected with the substrate through the torsion arms, the shaft sleeves and the support and electric connection columns.

3. The micro-mirror structure adopting movable support according to claim 2, wherein the micro-bridge deck comprises a first sub-micro-bridge deck and a second sub-micro-bridge deck, the first sub-micro-bridge deck and the second sub-micro-bridge deck are arranged in a coplanar manner and are respectively connected to two sides of the torsion arm, the first sub-micro-bridge deck is provided with a first sub-micro-mirror surface, and the second sub-micro-bridge deck is provided with a second sub-micro-mirror surface.

4. A micromirror structure using movable support according to claim 3, wherein the first sub-micromirror mirror and the second sub-micromirror mirror are provided with addressing electrodes, respectively, on the substrate under the first sub-micromirror mirror and the second sub-micromirror mirror.

5. The micro-mirror structure adopting movable support according to claim 2, wherein the two ends of the torsion arm are provided with supporting parts, the shaft sleeve is provided with shaft holes, the two ends of the torsion arm are supported on the bottom of the shaft holes through the supporting parts, and when the micro-mirror surface is driven, the micro-bridge deck is driven to deflect by taking the supporting parts as fulcrums.

6. The micro mirror structure using movable support according to claim 1, wherein the support part has a rectangular, tapered or arc-shaped cross section.

7. The micro mirror structure using movable support according to claim 1, wherein the support and electric connection post is formed in a trench provided in a sacrificial layer between the substrate and the micro bridge deck, the support and electric connection post including a conductor formed on a part of a side wall surface of the trench and a support body located inside the conductor, the micro bridge deck being movably supported on the support body and the conductor, the micro mirror being electrically connected to the substrate through the conductor, the micro bridge structure being released by removing the sacrificial layer; the micro-mirror structures are arranged on the substrate in a row-column mode to form an array, and the same supporting and electric connecting column is shared between any two adjacent micro-mirror structures in the same row or the same column, or the supporting and electric connecting columns of any two adjacent micro-mirror structures in the same row or the same column are arranged close to each other and are formed on the side walls of the opposite sides of the same groove.

8. A method of fabricating a micromirror structure using a movable support, comprising:

providing a substrate;

forming a sacrificial layer on the substrate, forming two supporting and electric connecting columns on the substrate in the sacrificial layer, a conductive shaft sleeve on each supporting and electric connecting column, conductive torsion arms penetrating through the two shaft sleeves at two ends and keeping a space, and a micromirror surface connected to the side surface of the torsion arm;

and removing the sacrificial layer, so that the torsion arm and the micromirror mirror connected with the torsion arm fall on the shaft sleeve, and the micromirror mirror is movably supported on the support and the electric connecting column through the movable fit between the two ends of the torsion arm and the shaft sleeve.

9. The method of fabricating a micromirror structure using movable supports according to claim 8, wherein a sacrificial layer is formed on the substrate, two support and electrical connection posts on the substrate are formed in the sacrificial layer, and a conductive bushing is formed on each of the support and electrical connection posts, and conductive torsion arms are inserted into the two bushings through both ends with a space therebetween, and micromirror mirrors are attached to sides of the torsion arms, comprising:

forming a first sacrificial layer on the surface of the substrate;

forming two trenches on the first sacrificial layer surface and stopping on the substrate surface;

forming one of the support and electrical connection posts in each of the trenches;

forming a shaft sleeve bottom pattern on the top surface of each supporting and electric connecting column;

forming a second sacrificial layer on the surface of the first sacrificial layer, and covering the bottom graph of the shaft sleeve;

forming the torsion arm and the micromirror surfaces connected to the two sides of the torsion arm on the surface of the second sacrificial layer, and enabling the two ends of the torsion arm to be respectively positioned above the bottom patterns of the two shaft sleeves;

forming a third sacrificial layer on the surface of the second sacrificial layer, and covering the torsion arm and the micromirror surface;

forming two pairs of through holes on the surface of the third sacrificial layer, wherein each pair of through holes are positioned on two sides of the torsion arm and stop on the pattern surface at the bottom of the shaft sleeve;

forming a shaft sleeve side part pattern with the lower end connected with the shaft sleeve bottom pattern in each pair of through holes, and forming two shaft sleeve top patterns respectively connected with the upper ends of each pair of shaft sleeve side part patterns on the surface of the third sacrificial layer, thereby forming the shaft sleeve on the top surface of the supporting and electric connecting column, and enabling the two ends of the torsion arm to penetrate into the two shaft sleeves at a certain interval;

the sacrificial layer is removed, so that the torsion arm and the micromirror mirror connected with the torsion arm fall on the shaft sleeve, and the micromirror mirror is movably supported on the support and the electric connection column through the movable fit between the two ends of the torsion arm and the shaft sleeve, and the method specifically comprises the following steps:

and removing the first sacrificial layer to the third sacrificial layer, so that the torsion arm and the micromirror surface connected with the torsion arm naturally fall under the action of gravity until the two ends of the torsion arm fall on the pattern surface at the bottom of the shaft sleeve to obtain support, and the torsion arm and the shaft sleeve form movable fit through the two ends, so that the micromirror surface is movably supported on the support and the electric connecting column.

10. The method of manufacturing a micro mirror structure using a movable support according to claim 9, wherein the forming the torsion arm on the surface of the second sacrificial layer, and the micro mirror surfaces connected to both sides of the torsion arm, and the positioning both ends of the torsion arm above the two patterns at the bottom of the shaft sleeve, respectively, specifically comprises:

forming grooves on the surface of the second sacrificial layer, and enabling two ends of the grooves to be respectively positioned above the bottom patterns of the two shaft sleeves;

forming a micromirror metal layer on the surface of the second sacrificial layer, and filling the grooves to form a supporting part in the grooves;

patterning the micromirror metal layer, further forming the torsion arm on the supporting part, and connecting the micromirror mirror surfaces on two sides of the torsion arm, so that two ends of the torsion arm are respectively positioned above the two shaft sleeve bottom patterns;

after the first sacrificial layer is removed to the third sacrificial layer, the torsion arm is supported by the pattern surface of the bottom of the shaft sleeve, and is in movable fit with the shaft sleeve through the supporting part.