US20070199823A1 - Method of manufacturing mirror support post of micromirror device using electro-plating process - Google Patents
Method of manufacturing mirror support post of micromirror device using electro-plating process Download PDFInfo
- Publication number
- US20070199823A1 US20070199823A1 US11/363,846 US36384606A US2007199823A1 US 20070199823 A1 US20070199823 A1 US 20070199823A1 US 36384606 A US36384606 A US 36384606A US 2007199823 A1 US2007199823 A1 US 2007199823A1
- Authority
- US
- United States
- Prior art keywords
- support post
- mirror support
- mirror
- forming
- micromirror device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/02—Electroplating of selected surface areas
- C25D5/022—Electroplating of selected surface areas using masking means
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D7/00—Electroplating characterised by the article coated
- C25D7/08—Mirrors; Reflectors
Definitions
- the present invention relates to a digital micromirror device, and more particularly, to a method of manufacturing a digital micromirror device having a perfectly flat mirror surface, in which the hole of a mirror surface from which light is reflected is obviated by forming a mirror support post portion using an electro-plating process, unlike the related art digital micromirror device in which a hole is formed at the center of the mirror surface so that the reflection efficiency of light is degraded.
- FIG. 1 is a cross-sectional view of a micromirror device in the related art, which is cut on a center line.
- the digital micromirror device was first developed by Texas Instruments Incorporated (U.S.).
- U.S. Pat. No. 5,535,047 issued on Jul. 09, 1996 entitled “Active Yoke Hidden Hinge Digital Micromirror Device” granted to Larry J. Hornbeck.
- the micromirror device is driven by electrostatic force and adopts a method in which the path of incident light is changed by reflecting the light according to a driving angle.
- the micromirror device is generally used in cantilever display fields.
- the related art micromirror device compises a mirror 11 for reflecting incident light, a mirror support post 13 for supporting the mirror surface, a twisting hinge 14 to operate the bi-directional tilting of the micromirror device, a conducting layer 15 for electrical connection, and a yoke 16 that connects the twisting hinge 14 , the mirror support post 13 and so on.
- a hole 12 exists at the center of the mirror surface due to the structure of the mirror 11 that reflects the incident light and the support post 13 that supports the mirror surface.
- the mirror 11 and the mirror support post 13 are simultaneously fabricated using a deposition method such as sputtering.
- the hole 12 is inevitably formed at the center of the mirror surface. Reflected light is lost due to the hole 12 of the mirror surface, which results in a reduction in the contrast ratio when displaying images. Furthermore, a central portion within one pixel is always dark.
- the present invention has been made in view of the above problems, and it is an object of the present invention to enhance light reflection efficiency and the contrast ratio by forming a perfectly flat mirror surface by fabricating mirror support posts of a micromirror device using a plating process.
- a method of manufacturing a mirror support post of a micromirror device using a plating process compises the steps of forming a seed electrode on a substrate, forming a lower electrode, a driving unit of a micromirror and a sacrificial layer comprising a mirror support post formation region on the seed electrode, and forming a mirror support post in the mirror support post formation region using an electro-plating process.
- the mirror support post may have the same height as the sacrificial layer.
- the mirror support post may have a flat surface.
- a method of manufacturing a mirror support post of a micromirror device using a plating process comprises the steps of forming a lower electrode, a sacrificial layer and a cantilever support post of a driving unit of a micromirror on a substrate, forming a seed electrode on the cantilever support post of the driving unit of the micromirror, forming a cantilever of the micromirror and forming a sacrificial layer comprising a mirror support post formation region on the seed electrode, and forming the mirror support post in the mirror support post formation region using an electro-plating process.
- the mirror support post may have the same height as the sacrificial layer.
- the mirror support post may have a flat surface.
- a method of manufacturing a mirror support post of a micromirror device using a plating process comprises the steps of forming a conducting layer on a substrate, forming a lower sacrificial layer, a hinge and a yoke on the conducting layer, forming an upper sacrificial layer comprising a mirror support post formation region on the yoke and the hinge, and forming a mirror support post in the mirror support post formation region by an electro-plating process.
- the mirror support post may have the same height as the upper sacrificial layer.
- the mirror support post may have a flat surface.
- FIG. 1 is a cross-sectional view of a micromirror device in the related art, which is cut on a center line;
- FIG. 2 is a dismantled perspective view schematically showing the construction of a micromirror device according to the present invention
- FIG. 3 is a plan view of the micromirror device shown in FIG. 2 , which is vertically viewed downward from the substrate after the mirror is removed according to the present invention
- FIG. 4 is a flowchart schematically illustrating a plating process of a mirror support post of a micromirror device according to the present invention
- FIG. 5 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to an embodiment of the present invention
- FIG. 6 is a flowchart illustrating an electroplating process of a mirror support post portion of a micromirror device according to another embodiment of the present invention.
- FIG. 7 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to still another embodiment of the present invention.
- FIG. 8 shows a Scanning Electron Microscope (SEM) photograph of micromirror devices that are actually fabricated according to the present invention.
- FIG. 2 is a dismantled perspective view schematically showing the construction of a micromirror device according to the present invention.
- the micromirror device compises a mirror 20 , a substrate 21 , a plurality of electrodes 22 , a plurality of cantilever support posts 23 , a plurality of cantilevers 25 and a plurality of mirror support posts 24 .
- an addressing circuit (not shown) is formed in the substrate 21 .
- the electrodes 22 are formed on the substrate 21 .
- Each of the three cantilever support posts 23 is attached to the substrate 21 .
- Each of three cantilevers 25 has a flat plate and has its one end attached on each of the three cantilever support posts 23 .
- the mirror 20 is disposed on the mirror support posts 24 , each attached on the other end of each of the cantilevers 25 .
- the cantilever support posts 23 that support the neighboring cantilevers 25 intersect each other on the substrate 21 .
- the three mirror support posts 24 are adhered to the mirror 20 at locations opposite to that of the cantilever support posts 23 of the cantilevers 25 .
- the cantilever 25 that connects the cantilever support post 23 and the mirror support post 24 is bent up and down under expansion and contraction stress by electrostatic force generated by a voltage applied to the electrodes 22 on the substrate 21 and thus rotates the mirror 20 .
- the mirror 20 has two kinds of rotation states where it is inclined either right or left at a predetermined angle depending on a direction in which electrostatic force is applied.
- the rotation angle of the mirror can also be controlled according to an amount of applied electrostatic force.
- a pair of the electrodes 22 for driving the mirror 20 is connected to an addressing circuit (not shown).
- FIG. 3 is a plan view of the micromirror device shown in FIG. 2 , which is vertically viewed downward from the substrate after the mirror is removed according to the present invention.
- the cantilever support posts 23 for supporting the cantilevers 25 and the mirror support posts 24 for supporting the mirror 20 are symmetrical to each other on the basis of the horizontal center line (a-a′) of the substrate.
- the electrodes 22 for addressing the mirror are symmetrical to each other on the basis of the vertical center line (b-b′) of the substrate.
- the electrodes 22 are not overlapped with the cantilever support posts 22 .
- the present invention can be implemented even if the electrodes 22 and the cantilever support posts 23 do not overlap.
- the mirror is applied with some degree of force in two directions along which the mirror is rotated. Therefore, the mirror can have the two kinds of rotation states.
- FIG. 4 is a flowchart schematically illustrating a plating process of a mirror support post of the micromirror device according to the present invention.
- the plating process applied to the present invention comprises a general electro-plating method.
- a seed metal 35 i.e., the conducting layer is previously formed on the substrate 36 so that electricity can conduct on the surface of the substrate 36 .
- a photoresist film used in the pattern layer 34 can be formed of an organic material such as polymer.
- the organic material is not conductive and can be thus used as an electro-plating mask.
- the photoresist film that is no longer necessary is removed using an organic solvent such as acetone.
- the photoresist film can be removed easily using an organic solvent since it is an organic material.
- the electro-plating metal refers to the mirror support posts of the present invention
- the seed metal 35 of the selective region be removed to prevent the entire substrate from being electrically by the seed metal 35 .
- the seed metal 35 below the electro-plating metal is not removed, but only the seed metal 35 in the region where the electro-plating metal is not formed is removed.
- the plating process can deposit the conducting layer without limitation in height using an external power supply source that is electrically connected and the plating solution.
- a metal pole with a high vertical ratio can be formed in fully filled form. It is therefore possible to fabricate the mirror support posts that support the mirror in fully filled form in the micromirror manufacturing method of the present invention.
- FIG. 5 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to an embodiment of the present invention.
- FIG. 5 is a cross-sectional view of the micromirror device taken along line a-a′ in FIG. 3 .
- a mirror support post formation region 41 is required.
- the mirror support post formation region 41 is formed using a photolithography process.
- a seed electrode 44 is first formed on a substrate 45 .
- a lower electrode 48 for applying a voltage to rotate the mirror, a driver 43 having a cantilever and a cantilever support post, for driving the micromirror device, and a sacrificial layer 42 comprising the mirror support post formation region 41 are formed on the seed electrode 44 by means of a photolithography process.
- the photolithography process is a process that has been widely known to those skilled in the art. Therefore, description thereof will be omitted.
- the region 41 in which the mirror support post will be formed is patterned by the process.
- the region 41 formed in FIG. 5 ( a ) is filled with metal by means of the electro-plating method described with reference to FIG. 4 .
- the metal 46 becomes the mirror support post.
- the metal 46 filled by electro-plating has the same height as the sacrificial layer 42 .
- a mirror 47 is formed by a deposition process and a photolithography process.
- the region to be used as the mirror support post 46 is completely filled with a metal material.
- the mirror 47 is formed by a method, such as the deposition method, by forming the mirror support post 46 whose hole is fully filled, a region on which the mirror 47 will be deposited when forming the mirror 47 becomes perfectly flat. Therefore, the mirror 47 having a perfectly flat can be formed.
- the mirror support post be formed to have the same height as the sacrificial layer and to have a perfectly flat surface, by accurately controlling the plating method.
- the sacrificial layer 42 is removed and the seed electrode 44 formed for the plating process is removed, if needed, for the purpose of avoiding an electrical short circuit.
- FIG. 6 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to another embodiment of the present invention.
- FIG. 6 is a cross-sectional view of the micromirror device taken along line a-a′ in FIG. 3 .
- the mirror support post portion shown in FIG. 6 is different from that of FIG. 5 in that a seed electrode 54 for electrical connection of an electro-plating process is formed not on a substrate 56 , but formed in a sacrificial layer 52 .
- a mirror support post formation region 51 is formed using a photolithography process.
- a lower electrode 55 to which a voltage is applied to rotate the mirror, the seed electrode 54 formed in the sacrificial layer 52 and a cantilever support post of a driving unit 53 of the micromirror, the driving unit 53 of the micromirror having a cantilever and a cantilever support post, and a sacrificial layer 52 comprising the mirror support post formation region 51 are formed by a photolithography process.
- the photolithography process is a process that has been widely known to those skilled in the art. Therefore, description thereof will be omitted.
- the region 51 in which a mirror support post will be formed is patterned by the process.
- the region 51 formed in FIG. 6 ( a ) is filled with metal by means of the electro-plating method that has been described with reference to FIG. 4 .
- the mirror support post 57 that is fully filled can be formed without limitation in height. In this case, the metal 57 filled by electro-plating becomes the mirror support post.
- the electroplated region 51 is formed to have the same height as the sacrificial layer 52 .
- a mirror 58 is deposited on the mirror support post 57 .
- the mirror 58 is formed by a method, such as the deposition method, by forming the mirror support post 57 as described above, the mirror 57 having a perfectly flat surface can be fabricated.
- the conducting layer 54 for electrical connection of the electro-plating process can be formed between-the-sacrificial layer 52 .
- the micromirror structure comprises a conductive material such as metal for the purpose of voltage application.
- the mirror support post 57 that is fully filled can be formed without limitation in height.
- the plated region can be formed to have the same height as the sacrificial layer 52 .
- the mirror 58 with a perfectly flat surface can be formed if the mirror 58 is formed using a method such as the deposition method.
- the sacrificial layer 52 is removed and the metal layer 54 formed for the plating process is then removed, as necessary, for the purpose of avoiding an electrical short circuit.
- FIG. 7 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to still another embodiment of the present invention.
- FIG. 7 is a flowchart illustrating an electro-plating process of the mirror support post portion of the micromirror device shown in FIG. 1 .
- FIG. 7 ( a ) is a cross-sectional view of the micromirror device in which an upper sacrificial layer 61 and a lower sacrificial layer 62 are formed to form a conducting layer 65 , a hinge 64 , a yoke 66 and a mirror support post 63 .
- the conducting layer 65 for electrical connection is first formed on a substrate 70 .
- the lower sacrificial layer 62 for forming the hinge 64 is then formed.
- the lower sacrificial layer 62 is removed by a subsequent process. A space from which the lower sacrificial layer 62 is removed remains as an air gap.
- the hinge 64 is formed on the lower sacrificial layer 62 .
- the yoke 66 is then formed on the hinge 64 .
- the upper sacrificial layer 61 comprising a mirror support post formation region 60 is formed on the yoke 66 and the hinge 64 .
- the mirror support post 63 is formed in the mirror support post formation region 60 by an electro-plating process as described above.
- the mirror support post 63 may have the same height as the upper sacrificial layer 61 and may have a perfectly flat surface.
- the mirror 64 is deposited on the upper sacrificial layer 61 and the mirror support post 63 . As shown in FIG. 7 ( d ), the upper sacrificial layer 61 and the lower sacrificial layer 62 are removed.
- the conducting layer 65 may be used as a seed electrode (refers to 44 in FIG. 5 ) for electrical connection for the purpose of the electro-plating process.
- the conducting layer 65 may be formed on the hinge 64 and may be used as the seed electrode, as shown in FIG. 6 .
- the conducting layer 65 may be removed, if necessary, for avoiding an electrical short circuit.
- FIG. 8 is a SEM photograph of micromirror devices that are actually fabricated according to the present invention.
- a pole that supports a mirror surface is formed by a plating method. Therefore, a hole of a mirror surface that reflects light can be obviated. Therefore, the present invention is advantageous in that a micromirror device can have a perfectly flat mirror surface.
- the present invention is advantageous in that it can improve the reflection efficiency of light, obtain a high contrast ratio of display images with a high quality and save power consumption.
Abstract
An embodiment of the present invention relates to a digital micromirror device. More particularly, an embodiment of the present invention relates to a method of manufacturing a digital micromirror device having a perfectly flat mirror surface, wherein a hole of a mirror surface from which light is reflected is obviated by forming a mirror support post portion using an electro-plating process, unlike the related art digital micromirror device in which the hole is formed at the center of the mirror surface, thereby degrading the reflection efficiency of light.
Description
- 1. Field of the Invention
- The present invention relates to a digital micromirror device, and more particularly, to a method of manufacturing a digital micromirror device having a perfectly flat mirror surface, in which the hole of a mirror surface from which light is reflected is obviated by forming a mirror support post portion using an electro-plating process, unlike the related art digital micromirror device in which a hole is formed at the center of the mirror surface so that the reflection efficiency of light is degraded.
- 2. Background of the Related Art
-
FIG. 1 is a cross-sectional view of a micromirror device in the related art, which is cut on a center line. - As shown in
FIG. 1 , the digital micromirror device was first developed by Texas Instruments Incorporated (U.S.). An example of the prior art micromirror device is disclosed in U.S. Pat. No. 5,535,047 (issued on Jul. 09, 1996 entitled “Active Yoke Hidden Hinge Digital Micromirror Device” granted to Larry J. Hornbeck. The micromirror device is driven by electrostatic force and adopts a method in which the path of incident light is changed by reflecting the light according to a driving angle. The micromirror device is generally used in cantilever display fields. - Referring to
FIG. 1 , the related art micromirror device compises a mirror 11 for reflecting incident light, amirror support post 13 for supporting the mirror surface, a twisting hinge 14 to operate the bi-directional tilting of the micromirror device, a conductinglayer 15 for electrical connection, and ayoke 16 that connects the twisting hinge 14, themirror support post 13 and so on. - A
hole 12 exists at the center of the mirror surface due to the structure of the mirror 11 that reflects the incident light and thesupport post 13 that supports the mirror surface. The mirror 11 and themirror support post 13 are simultaneously fabricated using a deposition method such as sputtering. As a result, thehole 12 is inevitably formed at the center of the mirror surface. Reflected light is lost due to thehole 12 of the mirror surface, which results in a reduction in the contrast ratio when displaying images. Furthermore, a central portion within one pixel is always dark. - It is therefore necessary to form a perfectly flat mirror surface by removing the
concave hole 12 existing at the center of the mirror surface to enhance the light use efficiency and the contrast ratio, to remove a dark region in an image, to save power consumption when displaying images and to implement images with a high quality. - Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to enhance light reflection efficiency and the contrast ratio by forming a perfectly flat mirror surface by fabricating mirror support posts of a micromirror device using a plating process.
- To achieve the above object, a method of manufacturing a mirror support post of a micromirror device using a plating process according to an embodiment of the present invention compises the steps of forming a seed electrode on a substrate, forming a lower electrode, a driving unit of a micromirror and a sacrificial layer comprising a mirror support post formation region on the seed electrode, and forming a mirror support post in the mirror support post formation region using an electro-plating process.
- In the step of forming the mirror support post, the mirror support post may have the same height as the sacrificial layer.
- In the step of forming the mirror support post, the mirror support post may have a flat surface.
- To achieve the above object, a method of manufacturing a mirror support post of a micromirror device using a plating process according to another embodiment of the present invention comprises the steps of forming a lower electrode, a sacrificial layer and a cantilever support post of a driving unit of a micromirror on a substrate, forming a seed electrode on the cantilever support post of the driving unit of the micromirror, forming a cantilever of the micromirror and forming a sacrificial layer comprising a mirror support post formation region on the seed electrode, and forming the mirror support post in the mirror support post formation region using an electro-plating process.
- In the step of forming the mirror support post, the mirror support post may have the same height as the sacrificial layer.
- In the step of forming the mirror support post, the mirror support post may have a flat surface.
- To achieve the above object, a method of manufacturing a mirror support post of a micromirror device using a plating process according to still another embodiment of the present invention comprises the steps of forming a conducting layer on a substrate, forming a lower sacrificial layer, a hinge and a yoke on the conducting layer, forming an upper sacrificial layer comprising a mirror support post formation region on the yoke and the hinge, and forming a mirror support post in the mirror support post formation region by an electro-plating process.
- In the step of forming the mirror support post, the mirror support post may have the same height as the upper sacrificial layer.
- In the step of forming the mirror support post, the mirror support post may have a flat surface.
- Further objects and advantages of the invention can be more completely understood from the following detailed description taken in conjunction with the accompanying drawings in which:
-
FIG. 1 is a cross-sectional view of a micromirror device in the related art, which is cut on a center line; -
FIG. 2 is a dismantled perspective view schematically showing the construction of a micromirror device according to the present invention; -
FIG. 3 is a plan view of the micromirror device shown inFIG. 2 , which is vertically viewed downward from the substrate after the mirror is removed according to the present invention; -
FIG. 4 is a flowchart schematically illustrating a plating process of a mirror support post of a micromirror device according to the present invention; -
FIG. 5 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to an embodiment of the present invention; -
FIG. 6 is a flowchart illustrating an electroplating process of a mirror support post portion of a micromirror device according to another embodiment of the present invention; -
FIG. 7 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to still another embodiment of the present invention; and -
FIG. 8 shows a Scanning Electron Microscope (SEM) photograph of micromirror devices that are actually fabricated according to the present invention. - These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
- The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings.
-
FIG. 2 is a dismantled perspective view schematically showing the construction of a micromirror device according to the present invention. - As shown in
FIG. 2 , the micromirror device compises amirror 20, asubstrate 21, a plurality ofelectrodes 22, a plurality ofcantilever support posts 23, a plurality ofcantilevers 25 and a plurality ofmirror support posts 24. - In the micromirror device, an addressing circuit (not shown) is formed in the
substrate 21. Theelectrodes 22 are formed on thesubstrate 21. Each of the threecantilever support posts 23 is attached to thesubstrate 21. Each of threecantilevers 25 has a flat plate and has its one end attached on each of the threecantilever support posts 23. Themirror 20 is disposed on themirror support posts 24, each attached on the other end of each of thecantilevers 25. - The
cantilever support posts 23 that support the neighboringcantilevers 25 intersect each other on thesubstrate 21. The threemirror support posts 24 are adhered to themirror 20 at locations opposite to that of thecantilever support posts 23 of thecantilevers 25. - The
cantilever 25 that connects the cantilever support post23 and the mirror support post24 is bent up and down under expansion and contraction stress by electrostatic force generated by a voltage applied to theelectrodes 22 on thesubstrate 21 and thus rotates themirror 20. - In the three
mirror support posts 24 that support themirror 20, a location at which thesubstrate 21 is fixed and a location at which themirror 20 is attached intersect each other. Therefore, themirror 20 has two kinds of rotation states where it is inclined either right or left at a predetermined angle depending on a direction in which electrostatic force is applied. The rotation angle of the mirror can also be controlled according to an amount of applied electrostatic force. - A pair of the
electrodes 22 for driving themirror 20 is connected to an addressing circuit (not shown). -
FIG. 3 is a plan view of the micromirror device shown inFIG. 2 , which is vertically viewed downward from the substrate after the mirror is removed according to the present invention. - Referring to
FIG. 3 , thecantilever support posts 23 for supporting thecantilevers 25 and themirror support posts 24 for supporting themirror 20 are symmetrical to each other on the basis of the horizontal center line (a-a′) of the substrate. Theelectrodes 22 for addressing the mirror are symmetrical to each other on the basis of the vertical center line (b-b′) of the substrate. - It has been shown in
FIG. 3 that theelectrodes 22 are not overlapped with thecantilever support posts 22. However, the present invention can be implemented even if theelectrodes 22 and thecantilever support posts 23 do not overlap. - Through the above structure, the mirror is applied with some degree of force in two directions along which the mirror is rotated. Therefore, the mirror can have the two kinds of rotation states.
-
FIG. 4 is a flowchart schematically illustrating a plating process of a mirror support post of the micromirror device according to the present invention. - The plating process applied to the present invention comprises a general electro-plating method.
- In the general electro-plating method, if a
sample 31 becoming a conducting layer and anelectrode 33 are dipped into aplating solution 30 and are then applied with a voltage,metal ions 32 within theplating solution 30 form the conducting layer in thesample 31 according to a pattern shape of apattern layer 34. - In the plating process of forming the mirror support posts according to the present invention using the electro-plating method, a
seed metal 35, i.e., the conducting layer is previously formed on thesubstrate 36 so that electricity can conduct on the surface of thesubstrate 36. - For such electro-plating to be performed only in a selected region of the surface of the
substrate 36, it is necessary to block a non-conductive material using thepattern layer 34. A photoresist film used in thepattern layer 34 can be formed of an organic material such as polymer. The organic material is not conductive and can be thus used as an electro-plating mask. After the completion of the electro-plating, the photoresist film that is no longer necessary is removed using an organic solvent such as acetone. The photoresist film can be removed easily using an organic solvent since it is an organic material. - Where the electro-plating metal (refers to the mirror support posts of the present invention) is used without being separated from the
substrate 36, it is preferred that theseed metal 35 of the selective region be removed to prevent the entire substrate from being electrically by theseed metal 35. - In this case, the
seed metal 35 below the electro-plating metal is not removed, but only theseed metal 35 in the region where the electro-plating metal is not formed is removed. - Therefore, the plating process can deposit the conducting layer without limitation in height using an external power supply source that is electrically connected and the plating solution.
- If the method is used, a metal pole with a high vertical ratio can be formed in fully filled form. It is therefore possible to fabricate the mirror support posts that support the mirror in fully filled form in the micromirror manufacturing method of the present invention.
- The present applicant proposed Korean Patent Publication No. 2003-0023300 entitled “Micromirror Device Using Interdigitated Cantilevers and Its Applications.” A formation method of mirror support posts will be described based on the structure disclosed in the above patent.
-
FIG. 5 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to an embodiment of the present invention.FIG. 5 is a cross-sectional view of the micromirror device taken along line a-a′ inFIG. 3 . - As shown in
FIG. 5 , to fabricate mirror support posts, a mirror supportpost formation region 41 is required. - As shown in
FIG. 5 (a), the mirror supportpost formation region 41 is formed using a photolithography process. - A
seed electrode 44 is first formed on asubstrate 45. - A
lower electrode 48 for applying a voltage to rotate the mirror, adriver 43 having a cantilever and a cantilever support post, for driving the micromirror device, and asacrificial layer 42 comprising the mirror supportpost formation region 41 are formed on theseed electrode 44 by means of a photolithography process. - The photolithography process is a process that has been widely known to those skilled in the art. Therefore, description thereof will be omitted. The
region 41 in which the mirror support post will be formed is patterned by the process. - Referring to
FIG. 5 (b), theregion 41 formed inFIG. 5 (a) is filled with metal by means of the electro-plating method described with reference toFIG. 4 . In this case, themetal 46 becomes the mirror support post. - In this case, it is preferred that the
metal 46 filled by electro-plating has the same height as thesacrificial layer 42. - Referring to
FIG. 5 (c), after themirror support post 46 is formed, amirror 47 is formed by a deposition process and a photolithography process. - In this case, if the
mirror support post 46 is formed to have the same height as thesacrificial layer 42 by the electro-plating process, the region to be used as themirror support post 46 is completely filled with a metal material. - If the
mirror 47 is formed by a method, such as the deposition method, by forming themirror support post 46 whose hole is fully filled, a region on which themirror 47 will be deposited when forming themirror 47 becomes perfectly flat. Therefore, themirror 47 having a perfectly flat can be formed. - Therefore, it is preferred that the mirror support post be formed to have the same height as the sacrificial layer and to have a perfectly flat surface, by accurately controlling the plating method.
- Thereafter, the
sacrificial layer 42 is removed and theseed electrode 44 formed for the plating process is removed, if needed, for the purpose of avoiding an electrical short circuit. -
FIG. 6 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to another embodiment of the present invention.FIG. 6 is a cross-sectional view of the micromirror device taken along line a-a′ inFIG. 3 . - The mirror support post portion shown in
FIG. 6 is different from that ofFIG. 5 in that aseed electrode 54 for electrical connection of an electro-plating process is formed not on asubstrate 56, but formed in asacrificial layer 52. - Referring to
FIG. 6 (a), a mirror supportpost formation region 51 is formed using a photolithography process. - A
lower electrode 55 to which a voltage is applied to rotate the mirror, theseed electrode 54 formed in thesacrificial layer 52 and a cantilever support post of a drivingunit 53 of the micromirror, the drivingunit 53 of the micromirror having a cantilever and a cantilever support post, and asacrificial layer 52 comprising the mirror supportpost formation region 51 are formed by a photolithography process. - In the same manner as
FIG. 5 , the photolithography process is a process that has been widely known to those skilled in the art. Therefore, description thereof will be omitted. Theregion 51 in which a mirror support post will be formed is patterned by the process. - Referring to
FIG. 6 (b), theregion 51 formed inFIG. 6 (a) is filled with metal by means of the electro-plating method that has been described with reference toFIG. 4 . Themirror support post 57 that is fully filled can be formed without limitation in height. In this case, themetal 57 filled by electro-plating becomes the mirror support post. - In this case, it is preferred that the electroplated
region 51 is formed to have the same height as thesacrificial layer 52. - Referring to
FIG. 6 (c), after themirror support post 57 is formed, amirror 58 is deposited on themirror support post 57. - If the
mirror 58 is formed by a method, such as the deposition method, by forming themirror support post 57 as described above, themirror 57 having a perfectly flat surface can be fabricated. - The
region 51 that is previously defined by a photolithography process, which is one of processes of forming a semiconductor pattern, is filled using a plating process. - The conducting
layer 54 for electrical connection of the electro-plating process can be formed between-the-sacrificial layer 52. The micromirror structure comprises a conductive material such as metal for the purpose of voltage application. - In the electro-plating process, since deposition is performed beginning from an electrically connected portion, the hole is sequentially filled. The
mirror support post 57 that is fully filled can be formed without limitation in height. - The plated region can be formed to have the same height as the
sacrificial layer 52. - By forming the
mirror support post 57 as described above, themirror 58 with a perfectly flat surface can be formed if themirror 58 is formed using a method such as the deposition method. - Thereafter, the
sacrificial layer 52 is removed and themetal layer 54 formed for the plating process is then removed, as necessary, for the purpose of avoiding an electrical short circuit. -
FIG. 7 is a flowchart illustrating an electro-plating process of a mirror support post portion of a micromirror device according to still another embodiment of the present invention.FIG. 7 is a flowchart illustrating an electro-plating process of the mirror support post portion of the micromirror device shown inFIG. 1 . -
FIG. 7 (a) is a cross-sectional view of the micromirror device in which an uppersacrificial layer 61 and a lowersacrificial layer 62 are formed to form aconducting layer 65, ahinge 64, ayoke 66 and amirror support post 63. The conductinglayer 65 for electrical connection is first formed on asubstrate 70. The lowersacrificial layer 62 for forming thehinge 64 is then formed. The lowersacrificial layer 62 is removed by a subsequent process. A space from which the lowersacrificial layer 62 is removed remains as an air gap. Thehinge 64 is formed on the lowersacrificial layer 62. - The
yoke 66 is then formed on thehinge 64. The uppersacrificial layer 61 comprising a mirror supportpost formation region 60 is formed on theyoke 66 and thehinge 64. - Referring to
FIG. 7 (b), themirror support post 63 is formed in the mirror supportpost formation region 60 by an electro-plating process as described above. Themirror support post 63 may have the same height as the uppersacrificial layer 61 and may have a perfectly flat surface. - Referring next to
FIG. 7 (c), themirror 64 is deposited on the uppersacrificial layer 61 and themirror support post 63. As shown inFIG. 7 (d), the uppersacrificial layer 61 and the lowersacrificial layer 62 are removed. - In this case, if the micromirror device of
FIG. 1 is fabricated by completely filling themirror support post 63 using the electro-plating process, a perfectly flat mirror surface cam be formed as described above. - At this time, the conducting
layer 65 may be used as a seed electrode (refers to 44 inFIG. 5 ) for electrical connection for the purpose of the electro-plating process. Alternatively, the conductinglayer 65 may be formed on thehinge 64 and may be used as the seed electrode, as shown inFIG. 6 . On the other hand, after the uppersacrificial layer 61 and the lowersacrificial layer 62 are removed, the conductinglayer 65 may be removed, if necessary, for avoiding an electrical short circuit. -
FIG. 8 is a SEM photograph of micromirror devices that are actually fabricated according to the present invention. - As described above, according to the present invention, a pole that supports a mirror surface is formed by a plating method. Therefore, a hole of a mirror surface that reflects light can be obviated. Therefore, the present invention is advantageous in that a micromirror device can have a perfectly flat mirror surface.
- Furthermore, a perfectly flat mirror surface can be formed. Therefore, the present invention is advantageous in that it can improve the reflection efficiency of light, obtain a high contrast ratio of display images with a high quality and save power consumption.
- While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.
Claims (9)
1. A method of manufacturing a mirror support post of a micromirror device using a plating process, the method comprising the steps of:
forming a seed electrode on a substrate;
forming a lower electrode, a driving unit of a micromirror, and a sacrificial layer comprising a mirror support post formation region on the seed electrode; and
forming a mirror support post in the mirror support post formation region using an electro-plating process.
2. The method as claimed in claim 1 , wherein in the step of forming the mirror support post, the mirror support post has the same height as the sacrificial layer.
3. The method as claimed in claim 1 , wherein in the step of forming the mirror support post, the mirror support post has a flat surface.
4. A method of manufacturing a mirror support post of a micromirror device using a plating process, the method comprising the steps of:
forming a lower electrode, a sacrificial layer and a cantilever support post of a driving unit of a micromirror on a substrate;
forming a seed electrode on the cantilever support post of the driving unit of the micromirror;
forming a cantilever of the micromirror and a sacrificial layer comprising a mirror support post formation region on the seed electrode; and
forming the mirror support post in the mirror support post formation region using an electro-plating process.
5. The method as claimed in claim 4 , wherein in the step of forming the mirror support post, the mirror support post has the same height as the sacrificial layer.
6. The method as claimed in claim 4 , wherein in the step of forming the mirror support post, the mirror support post has a flat surface.
7. A method of manufacturing a mirror support post of a micromirror device using a plating process, the method comprising the steps of:
forming a conducting layer on a substrate;
forming a lower sacrificial layer, a hinge and a yoke on the conducting layer;
forming an upper sacrificial layer comprising a mirror support post formation region on the yoke and the hinge; and
forming a mirror support post in the mirror support post formation region by an electro-plating process.
8. The method as claimed in claim 7 , wherein in the step of forming the mirror support post, the mirror support post has the same height as the upper sacrificial layer.
9. The method as claimed in claim 7 , wherein in the step of forming the mirror support post, the mirror support post has a flat surface.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/363,846 US20070199823A1 (en) | 2006-02-28 | 2006-02-28 | Method of manufacturing mirror support post of micromirror device using electro-plating process |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/363,846 US20070199823A1 (en) | 2006-02-28 | 2006-02-28 | Method of manufacturing mirror support post of micromirror device using electro-plating process |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070199823A1 true US20070199823A1 (en) | 2007-08-30 |
Family
ID=38442963
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/363,846 Abandoned US20070199823A1 (en) | 2006-02-28 | 2006-02-28 | Method of manufacturing mirror support post of micromirror device using electro-plating process |
Country Status (1)
Country | Link |
---|---|
US (1) | US20070199823A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013116314A1 (en) * | 2012-01-30 | 2013-08-08 | Light Field Corporation | Full color phase-only spatial light modulator for holographic video display systems |
CN111352232A (en) * | 2015-04-01 | 2020-06-30 | 精工爱普生株式会社 | Electro-optical device |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6962419B2 (en) * | 1998-09-24 | 2005-11-08 | Reflectivity, Inc | Micromirror elements, package for the micromirror elements, and projection system therefor |
-
2006
- 2006-02-28 US US11/363,846 patent/US20070199823A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6962419B2 (en) * | 1998-09-24 | 2005-11-08 | Reflectivity, Inc | Micromirror elements, package for the micromirror elements, and projection system therefor |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013116314A1 (en) * | 2012-01-30 | 2013-08-08 | Light Field Corporation | Full color phase-only spatial light modulator for holographic video display systems |
CN111352232A (en) * | 2015-04-01 | 2020-06-30 | 精工爱普生株式会社 | Electro-optical device |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR100230536B1 (en) | Multi-level deformable mirror device and the producing method thereof | |
DE60214111T2 (en) | Jocheless digital micromirror device with concealed joint | |
JP2571878B2 (en) | Image creation device | |
CN1094204C (en) | Deformable mirror device and manufacturing method thereof | |
TWI358589B (en) | High quality and ultra large screen liquid crystal | |
CN102116984B (en) | Liquid crystal display device and method for fabricating the same | |
JP3165444B2 (en) | M × N thin-film actuated mirror array and method of manufacturing the same | |
CN1853130A (en) | Separable modulator | |
CN101847641B (en) | Array substrate, manufacturing method thereof and wide-viewing angle liquid crystal display | |
DE20122618U1 (en) | Projection system with array of rectangular micro-mirror elements for providing images at angles depending on mirror tilt angle in light ray steering system | |
JP2010197879A (en) | Display device, and method of correcting the same | |
CN100593752C (en) | Liquid crystal display panel, pixel structure and method of manufacture | |
CN1038706A (en) | Spatial light modulator and method | |
CN1610644A (en) | Fabrication of a reflective spatial light modulator | |
JPH07287177A (en) | Method for formation of array of freely rotatable elements | |
DE19606095A1 (en) | Mirror drive for micro-mirror field | |
CN1732506A (en) | Architecture of a reflective spatial light modulator | |
CN1758125A (en) | Thin-film transistor array base-plate and LCD and manufacture method thereof | |
EP1800158A1 (en) | Mirror and mirror layer for optical modulator and method | |
CN1651968A (en) | Spatial light modulator using an integrated circuit actuator and method of making and using same | |
CN101123262B (en) | Display substrate, method of fabricating the same, and liquid crystal display device having the same | |
TW200829955A (en) | Compatible MEMS switch architecture | |
WO1995012287A1 (en) | Thin film actuated mirror array and methods for its manufacture | |
US20070199823A1 (en) | Method of manufacturing mirror support post of micromirror device using electro-plating process | |
CN103135298A (en) | Thin film transistor (TFT) - liquid crystal display (LCD) array substrate and manufacturing method thereof, and display screen |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: KOREA ADVANCED INSTITUTE OF SCIENCE & TECHNOLOGY, Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:JEON, JIN-WAN;KIM, DAE-HYUN;YOON, JUN-BO;AND OTHERS;REEL/FRAME:017761/0926;SIGNING DATES FROM 20060224 TO 20060227 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |