KR0178220B1 - Manufacturing method of optical path regulation apparatus - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical path control apparatus, wherein two transistors are spaced apart by a predetermined distance from a top of a driving substrate having transistors embedded in a matrix state and having pads electrically connected to the transistors on a surface thereof, one of which is a pad. Forming a support portion in electrical contact with the substrate; forming a first sacrificial film on an upper portion of the driving substrate on which the support portion is not formed; a lower electrode, a deformation portion, an upper electrode, and an upper portion of the support portion and the first sacrificial film; Forming a drive transmission part, and defining the actuator by etching the drive transmission part at an intermediate portion between the support parts and etching the upper electrode, the deformation part, and the lower electrode so that both ends are extended to the support part; A second sacrificial film is formed on the upper electrode and the first sacrificial film where the transfer unit is not formed. Removing a predetermined portion of the first and second sacrificial films, exposing a driving substrate, forming a reflecting plate having one side attached to the exposed driving substrate and the other side attached to the driving transfer part; And removing the first and second sacrificial layers. Therefore, since the reflector is fixed by the actuator when the first and second sacrificial films are removed, the sticking phenomenon can be prevented from occurring.

Description

Manufacturing method of optical path control device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an optical path adjusting device used in a projection type image display device, and more particularly, to a method of manufacturing an optical path adjusting device capable of preventing sticking during cleaning and drying after removing a sacrificial film.

An image display apparatus is classified into a direct view type image display apparatus and a projection type image display apparatus according to a display method.

Direct image display device includes CRT (Cathode Ray Tube), which has good image quality but it has problems such as increase of weight and thickness as the screen gets bigger and expensive. There is.

Projection type image display apparatuses include a large crystal display (hereinafter referred to as an LCD), and such a large screen LCD can be thinned to reduce the weight. However, such LCDs have a high loss of light due to the polarizing plate, and thin film transistors for driving the LCD are formed for each pixel, so that there is a limit in increasing the aperture ratio (light transmission area).

Therefore, a projection type image display device using Actuated Mirror Arrays (hereinafter referred to as AMA) has been developed by Aura, United States. A projection image display device using AMA separates white light emitted from a light source into red, green, and blue light, and then changes the light path by driving an optical path adjusting device made of actuators. That is, the actuators are mounted on the actuators, and the actuators are individually driven to reflect the inclined mirrors, thereby changing the light path, thereby controlling the amount of light to project onto the screen. Therefore, an image appears on the screen. In the above, the actuator tilts the mirror by using an electric field generated and deformed by a voltage to which a deformable part made of piezoelectric or electrostrictive ceramic is applied. AMA is classified into one-dimensional AMA and two-dimensional AMA according to the driving method. One-dimensional AMA has mirrors arranged in an M × 1 array, and two-dimensional AMA has mirrors arranged in an M × N array. Therefore, the projection type image display apparatus using the one-dimensional AMA pre-scans the M × 1 beams using the scanning mirror, and the projection image display apparatus using the two-dimensional AMA displays the image by projecting the M × N luminous fluxes.

In addition, the actuator is classified into a bulk type and a thin film type according to the shape of the deformable portion. The bulk type thinly cuts a multilayer ceramic, mounts a ceramic wafer having a metal electrode therein on a driving substrate, processes it by sawing, and mounts a mirror. However, bulk actuators require a long process time because the actuators must be separated by sawing, and there is a problem that the response speed of the deformation part is slow. Therefore, a thin-film actuator that can be manufactured using a semiconductor process has been developed.

1 (a) to (d) is a manufacturing process diagram of the optical path control apparatus according to the prior art.

Referring to FIG. 1A, a driving substrate 11 having a pad (13) embedded in a matrix on a surface thereof and having a pad 13 made of a metal such as aluminum (Al) electrically connected to the transistor. A sacrificial film 15 for forming an air gap on the surface of the N-type) is formed to a thickness of about 1 to 2 μm. Then, the sacrificial film 15 in the portion where the pad 13 is formed is removed by a conventional photolithography method to expose the pad 13 and the surrounding driving substrate 11.

Referring to FIG. 1B, the membrane 17 is formed on the driving substrate 11 and the sacrificial layer 15 to a thickness of about 1 μm to 2 μm. In addition, after the opening 18 is formed to expose the pad 13 to a predetermined portion of the membrane 17, the plug 18 is electrically connected to the pads 13 by filling a conductive metal in the opening 18. plug 19). Subsequently, a lower electrode 21 having a thickness of about 500 to 2000 micrometers is formed on the membrane 17 so as to be electrically connected to the plug 19. Therefore, the pad 13 and the lower electrode 21 are electrically connected to each other by the plug 19.

Referring to FIG. 1C, the deformation part 23 and the upper electrode 25 are formed on the surface of the lower electrode 21. In the above description, the deformable part 23 is coated with a piezoelectric ceramic or a total distortion ceramic with a thickness of about 0.7 to 2 μm, and the upper electrode 25 is formed by depositing a metal having good reflection and electrical properties. Subsequently, the upper electrode 25, the deformable portion 23, the lower electrode 21, and the membrane 17 are etched to expose the driving substrate 11 to separate the actuators. When the actuators are separated, the upper electrode 25, the deformable portion 23, the lower electrode 21, and the membrane 17 are etched by reactive ion etching (RIE) using respective etching masks. Then, the protective film 27 is formed on the surface of the upper electrode 25 and the side surfaces of the actuators 30 by photoresist or the like.

Referring to FIG. 1D, the sacrificial layer 15 is removed with an etching solution such as hydrofluoric acid solution (HF). In this case, the protective layer 27 prevents sidewalls of the membrane 17 and the deformable portion 23 from being etched to separate the layers. The protective film 27 is then removed to form an air gap 29.

However, in the above-described conventional optical path control apparatus, a sticking phenomenon occurs in which the lower portion of the membrane adheres to the driving substrate by the surface tension of the cleaning liquid when the sacrificial film is removed by the solvent, the solvent is removed, and the cleaning solution is dried. There was a problem.

An object of the present invention is to provide a method for manufacturing an optical path control device that can prevent the sticking phenomenon during cleaning and drying to remove the solvent from which the sacrificial film is removed.

In the method of manufacturing the optical path control apparatus according to the present invention for achieving the above object, two transistors are spaced apart from each other by a predetermined distance on an upper part of a driving substrate having pads having transistors embedded in a matrix state and electrically connected to the transistors on a surface thereof. Forming a support part in which one of the support parts is in electrical contact with the pad, forming a first sacrificial film on an upper portion of the driving substrate on which the support part is not formed, and a lower electrode and a deformation part on the support part and the first sacrificial film. And forming an upper electrode and a driving transmission part, and defining the actuator by etching the driving transmission part at an intermediate portion between the supporting parts and etching the upper electrode, the deforming part, and the lower electrode so that both ends are extended to the supporting part. And an upper electrode on which the driving transfer unit is not formed and an upper portion of the first sacrificial layer. Forming a sacrificial film; exposing a driving substrate by removing predetermined portions of the first and second sacrificial films; and a reflecting plate having one side attached to the exposed driving substrate and the other side attached to the driving transfer part. And a step of removing the first and second sacrificial films.

1 (a) to (d) is a manufacturing process diagram of the optical path control apparatus according to the prior art.

2 (a) to (d) is a manufacturing process diagram of the optical path control apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

41: drive substrate 43: pad

45: support part 46: the first sacrificial film

47: lower electrode 49: deformation part

51: upper electrode 53: drive transmission unit

55: Actuator 56: the second sacrificial film

57: reflector

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 (a) to (d) is a manufacturing process diagram of the optical path control apparatus according to the present invention.

Referring to FIG. 2A, a transistor (not shown) is embedded in a surface in a matrix form and spaced a predetermined distance from a predetermined portion of a surface of a driving substrate 41 having a pad 43 electrically connected to the transistor. Thus, two support parts 45 are formed for each unit pixel. The support 45 is a conventional photolithography method after depositing a high melting point metal such as platinum (Pt) or platinum / titanium (Pt / Ti) to a thickness of about 1 to 2 μm on the surface of the driving substrate 41. Patterning by means of which one of the supports 45 is in electrical contact with the pad 43. The first sacrificial layer 46 is formed by depositing PSG (Phospho-Silicate Glass) at the same thickness as that of the support 43 on a portion where the support 43 of the driving substrate 41 is not formed.

Referring to FIG. 2 (b), platinum (Pt) or platinum / titanium (Pt / Ti) or the like is deposited on the support part 45 and the first sacrificial film 46 by vacuum deposition or sputtering, or the like. The lower electrode 47 is formed by depositing the same to a thickness. The lower electrode 47 is formed to be electrically connected to the support 45. Therefore, the pad 43 and the lower electrode 47 are electrically connected by the support part 45. The deformation part 49 is formed on the surface of the lower electrode 47. The deformation part 49 is a piezoceramic such as BaTiO ₃ , PZT (Pb (Zr, Ti) O ₃ ) or PLZT (Pb, La) (Zr, Ti) O ₃ ), or PMN (Pb (Mg). , Nb) O ₃ ) and the like, and are formed by applying a total distortion ceramic such as Sol-Gel method, sputtering or CVD method to a thickness of about 1 to 2 μm. In the above, since the deformable portion 55 is formed thin, it is polarized by an image signal applied during driving without any additional polarization. Subsequently, the upper electrode 51 is formed on the deformation part 49. The upper electrode 51 is formed by depositing aluminum or copper, which is a metal having good electrical conductivity, to a thickness of about 1 to 2 μm. Subsequently, aluminum or copper, which is a metal having the same electrical conductivity as the upper electrode 51, is deposited on the upper electrode 51 to a thickness of about 1 to 2 μm to form the driving transmission part 53.

Referring to FIG. 2C, the actuator 55 is etched by etching the driving transmission part 53, the upper electrode 51, the deforming part 49, and the lower electrode 47 by a photolithography method. In this case, the driving transfer part 53, the upper electrode 51, the deformable part 49, and the lower electrode 47 each require a separate etching mask. That is, the drive transmission part 53 should be formed so as to be positioned in the middle portion between the support parts 45, and the mask in which the upper electrode 51 and the deformable part 49 are etched is deformed in the etching solution. Use as a mask for etching the portion 49 and the lower electrode 47 becomes inappropriate. A second sacrificial film 56 is formed by depositing (not shown) PSG (Phospho-Silicate Glass) that is the same as the exposed first sacrificial film 46. In the above, the second sacrificial film 56 should be formed such that the surfaces of the first sacrificial film 46 and the driving transmission part 53 are exposed on the upper electrode 51 on which the driving transmission part 53 is not formed. do.

Referring to FIG. 2D, the first and second sacrificial layers 46 and 56 are patterned to expose a predetermined portion of the driving substrate 41. The reflective plate 57 is formed on the exposed portions of the drive transfer unit 53, the second sacrificial film 56, and the drive substrate 41. The reflector plate 57 is formed by a method such as sputtering or vacuum deposition of aluminum or copper having a good electrical characteristic as well as electrical characteristics to a thickness of about 1000 to 3000 kPa, and the upper electrode 51 by the drive transfer unit 53. Is electrically connected to the Then, a predetermined portion of one side attached to the driving substrate 41 by the photolithography method is connected to a reflecting plate (not shown) driven by an adjacent actuator (not shown), and the other side The end is patterned to coincide with the drive transmission section 53. Then, the first and second sacrificial films 46 and 56 are removed with an etching solution such as hydrofluoric acid (HF), washed and dried. At this time, the actuator 55 is fixed to the other end of the reflecting plate 57 to prevent the sticking phenomenon.

As described above, in the optical path adjusting device according to the present invention, two unit actuators are formed at an upper portion of a driving substrate, and either end of the lower portion is electrically connected to the supporting portion over both ends thereof. An actuator, a deformable part, and an upper electrode are sequentially formed, and an actuator including a drive transmission part electrically connected to the upper electrode in an intermediate part having the largest bending in an upper direction that is not in contact with the support part of the upper electrode, and one side of the driving substrate. It is attached to the upper portion of the electrically connected to the reflector plate driven to the adjacent actuator and the lower end of the other end is made of a reflector plate having a step shape attached to the electrically connected to the drive transmission of the actuator.

As described above, an example of the optical path control device manufactured by the method for manufacturing the optical path control device according to the present invention is detailed in the patent application filed by the applicant of the Korean Patent Office on June 30, 1995 under the name of the optical path control device. (See Patent Application No. 95-18672).

Therefore, the present invention has the advantage that the sticking phenomenon can be prevented from occurring because the reflector is fixed by the actuator when the first and second sacrificial films are removed.

Claims (17)

The transistors are embedded in a matrix state and two are spaced apart by a predetermined distance per unit actuator on the driving substrate 41 having pads 43 electrically connected to the transistors on one surface thereof, and one of them is in electrical contact with the pads 43. Forming a supporting part 45 to be formed, forming a first sacrificial film 46 on an upper portion of the driving substrate 41 on which the supporting part 45 is not formed, and providing the supporting part 45 and the first sacrificial material. Forming a lower electrode 47, a deformable portion 49, an upper electrode 51, and a drive transfer portion 53 on the film 46; and the drive transfer portion 53 on the support portion 45. A process of defining an actuator 55 by etching the upper electrode 51, the deformable part 49, and the lower electrode 47 so as to extend over the support part 45 at both ends thereof; The second electrode is disposed on the upper electrode 51 and the first sacrificial layer 46 where the driving transmission unit 53 is not formed. Forming a film 56, removing a predetermined portion of the first and second sacrificial films 46 and 56 to expose the driving substrate 41, and exposing the driving substrate 41 to the exposed driving substrate 41. An optical path adjusting device including a step of forming a reflector plate 57 having one side attached thereto and the other side attached to the drive transmission unit 53; and removing the first and second sacrificial films 46 and 56. Manufacturing method. The method according to claim 1, wherein the support part (45) is formed by depositing a pattern selected from a solid solution metal including platinum and platinum / titanium to a thickness of 1 to 2 µm and then patterning the support part (45). The method of claim 1, wherein the first sacrificial film (46) is formed by depositing PSG to the same thickness as the support portion (45). The method of manufacturing an optical path control device according to claim 1, wherein the deformation part (49) is formed of a piezoelectric ceramic of BaTiO ₃ , PZT or PLZT. The method of manufacturing an optical path control device according to claim 1, wherein the deformable portion (49) is formed of a total distortion ceramic of PMN. A method according to claim 4 or 5, wherein the deformable portion (49) is formed by a rotary coating method, a spraying method, a sputtering method or a chemical vapor deposition method. The method of manufacturing an optical path control device according to claim 6, wherein the deformation part (49) is formed to a thickness of 1 to 2 mu m. The method according to claim 1, wherein the upper electrode (51) is formed from a metal having good electrical conductivity including aluminum and copper. The method of manufacturing an optical path control apparatus according to claim 8, wherein the upper electrode (51) is formed to a thickness of 1 to 2 mu m. The method of manufacturing an optical path control apparatus according to claim 1, wherein the drive transmission unit (53) is formed by selecting from a metal having good electrical conductivity including aluminum and copper. The method of manufacturing an optical path control device according to claim 10, wherein the drive transmission part is formed to a thickness of 1 to 2 탆. The method of claim 1, wherein the second sacrificial layer (56) is formed of PSG. The method of manufacturing an optical path control apparatus according to claim 1, wherein the reflecting plate is formed from a metal having good electrical properties as well as reflective properties including aluminum and copper. The method of manufacturing an optical path adjusting device according to claim 13, wherein the reflecting plate is formed to have a thickness of 1000 to 3000 mW. 15. The method of claim 14, wherein the reflecting plate is formed by sputtering or vacuum deposition. The method of claim 1, wherein the first and second sacrificial films (46, 56) are removed by a wet method using hydrofluoric acid. The method of manufacturing an optical path control device according to claim 1, further comprising a step of cleaning and drying after removing the first and second sacrificial films (46, 56).