KR0179618B1 - Manufacturing method for light modulation device - Google Patents

Abstract

The present invention provides a method of manufacturing an optical path control apparatus capable of minimizing damage to a deformation part in a method of manufacturing an AMA as an optical path control apparatus employed in a projection image display apparatus. In the manufacturing method of the present invention, the sacrificial layer 35 is formed so that the pad is not formed in contact with the pad on the upper surface of the driving substrate 31 having the transistor 33 embedded in a matrix and electrically connected to the transistor. The first step of forming a support portion 37 surrounding the pad 33 on a portion where the sacrificial layer 35 is not formed on the substrate 31, and the sacrificial layer 35 and the support portion 37 are formed. A second process of depositing a membrane 39 on an upper portion of the membrane 39 and forming a contact groove so that the pad 33 is exposed to a predetermined portion of the membrane 39 and the support portion 37. A third process of forming a plug 41 to contact the 33 and applying a signal electrode 43 on the membrane 39 to be in contact with the plug 41, on the surface of the signal electrode 43. The deformation part 45 is deposited and the signal electrode 43 and the deformation part 45 are supported by the support part 37. In the fourth step of patterning only the corresponding portions, the insulating film 47 is deposited on the entire surface, and the insulating film 47 and the membrane 39 are patterned so that the sacrificial film 35 is exposed. After the separation process, the sacrificial layer 35 is removed using the insulating layer 47 as a mask, the polymer layer 49 is filled in the space where the sacrificial layer 35 is removed, and the deformation unit 45 is formed. And the sixth step of removing the polymer layer 49 after forming the reflective film 51 on the entire surface after removing the insulating film 47 on the?

Description

Manufacturing method of optical path control device

1 (a) to (d) are process cross-sectional views for explaining the manufacturing method of the optical path control apparatus according to the prior art.

2 (a) to (i) is a cross-sectional view for explaining the manufacturing method of the optical path control apparatus according to an embodiment of the present invention.

3 is a cross-sectional perspective view showing an optical path control device manufactured by the manufacturing method of FIG.

4A to 4C are cross-sectional views illustrating a method of manufacturing an optical path control apparatus according to another embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

31: driving substrate 33: pad

35: sacrificial film 37: support

39: membrane 41: plug

43: signal electrode 45: deformation part

47: insulating film 49: polymer layer

51: reflecting film 50: actuator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical path adjusting device, and more particularly, to a method for manufacturing an actuated mirror array (hereinafter, abbreviated as AMA) as an optical path adjusting device employed in a projection image display device. It is about.

In general, an image display device is classified into a direct view image display device such as a CRT (Cathode Ray Tube) or the like, and a projection image display device such as a liquid crystal display (LCD) according to the display method thereof.

Although CRTs have good image quality, they have a problem such that weight and thickness increase as the screen is enlarged, and the price is expensive. In addition, the LCD can be thin and low in weight, and can have a large screen. However, since the light loss due to the polarizing plate is large and the image driving thin film transistor is formed for each pixel, there is a limit in increasing the aperture ratio (light transmission area). There is a problem that is low.

Accordingly, a projection type image display apparatus using an actuated mirror array has been developed by Aura, United States. The image display apparatus using the AMA is distinguished from using a one-dimensional AMA and using a two-dimensional AMA. One-dimensional AMAs are arranged in an M × 1 array. Therefore, a projection image display apparatus using a one-dimensional AMA pre-scans M × 1 beams using a scanning mirror, and a projection image display apparatus using a two-dimensional AMA projects M × N beams to array an M × N pixel. It will have a shape with.

A manufacturing method for manufacturing the optical path control device constituting the AMA will be described with reference to FIG.

1 (a) to (d) are sectional views showing the manufacturing process of the optical path control apparatus according to the prior art.

First, transistors (not shown) are formed in a matrix form, and a sacrificial film 15 having a thickness of about 1 to 2 μm is formed on the surface of the driving substrate 11 having the connection terminal 13 electrically connected to the transistors thereon. . Here, the driving substrate 11 is made of an insulating material such as glass or aluminum (Al ₂ O ₃ ), or a semiconductor such as silicon. The sacrificial film 15 is formed of metal such as Mo, Cr, Fe, Ni, or Ti, or Phospho-Silicate Glass (PSG) or polycrystalline silicon. If the metal is sputtering or vacuum deposition, PSG In the case of polycrystalline silicon, the back surface is formed by spin coating method or phase cancer CVD method, and is formed by chemical vapor deposition (CVD) method. Thereafter, the predetermined portion of the sacrificial film 15 is removed by a conventional photolithograpy method to expose the connection terminal 13 and the driving substrate 11 around it. Then, a silicide such as silicon nitride (Si ₃ N ₄ ) or silicon oxide (SiO ₂ ) is laminated on the entire surface of the structure described above by a thickness of about 1 to 2 μm by sputtering or CVD, and then a sacrificial film ( By removing the silicide deposited on the upper part of 15) to form the support 17, the structure of FIG. 1 (a) is obtained.

Subsequently, a membrane 19 is formed on the sacrificial layer 15 and the support 17. Here, the membrane 19 is formed by stacking the same material as the support 17 with a thickness of about 0.7 to 2 μm by sputtering or CVD. Thereafter, the contact portion 21 is formed by removing the membrane 19 and the support portion 17 of the predetermined portion existing on the connection terminal 13. Subsequently, a plug 23 electrically connected to the connection terminal 13 is formed by filling a conductive metal such as tungsten or titanium in the contact groove 21. Next, platinum, platinum / titanium, or the like is applied to the entire surface of the above structure by a vacuum deposition method or a sputtering method with a thickness of about 500 to 2000 microns to form the signal electrode 25, thereby forming the structure of FIG. Get

Next, the deformation parts 27 and the reflective film 29 are sequentially stacked on the entire surface of the signal electrode 25. The deformable portion 27 may include piezoelectric ceramics such as BaTiO ₃ , PZT ((Zr, Ti) O ₃ ) or PLZT ((Pb, La) (Zr, Ti) O ₂ ), or PMN (Pb (Mg, A total distortion ceramic such as Nb) O ₂ ) is formed to a thickness of about 0.7 to 2 μm by a Sol-Sel method, a sputtering method, or a CVD method. The reflective film 29 is formed by applying a metal material having good reflection and electrical properties such as gold, platinum, or titanium to a thickness of about 500 to 2000 kPa by a vacuum deposition method or a sputtering method. Thereafter, predetermined portions of the reflective film 29, the deformable part 27, and the membrane 19 are removed by laser cutting or photolithography so that the edges of the supporting parts 17 are coincident with the edges of the supporting part 17. ) To remove the actuator. Subsequently, a photoresist or silicon nitride is laminated on the entire surface of the structure described above by CVD to form a protective layer 31, and then the protective layer 31 on the sacrificial film 15 is removed (FIG. 1). (c)].

Subsequently, the sacrificial film 15 is wet-etched and removed with an etching solution such as HF, and then the protective layer 31 is dry-etched and removed without using a mask to complete the actuator 20 (FIG. d)].

In the manufacturing method of the optical path adjusting apparatus according to the prior art, a photoresist or silicon nitride (Si ₃ N ₄ ) is applied as a protective layer for simultaneously protecting the reflective film 29 and the deformable portion 25. The sacrificial film is removed by wet etching. However, in the case of using a photoresist as a protective film, there is a fear that the deformed portion 25 is damaged due to the leakage phenomenon of the etching solution in the thin portion due to the thickness difference of the photoresist during wet etching. In addition, when silicon nitride is used as the protective film, leakage of the etching solution during wet etching can be prevented, and damage to the deformable portion 25 can be prevented. However, silicon nitride as the protective film after the step of removing the sacrificial film can be prevented. As a stress is generated in the membrane 19 on the air gap during the dry etching to remove the defects, defects may occur at the connection portions of the membrane 19 and the support 17, the signal electrode 25 and the plug 23. There existed a problem that removal of the silicon nitride was difficult.

Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide a method of manufacturing an optical path control apparatus capable of preventing damage to a deformation part in a method of manufacturing an AMA as an optical path control apparatus employed in a projection image display apparatus. There is this.

According to a preferred embodiment of the manufacturing method of the optical path control apparatus according to the present invention for achieving the above object, the pad is formed on the top of the driving substrate in which the transistor is embedded in a matrix form and the pad electrically connected to the transistor is formed on the surface thereof. Forming a sacrificial film so as not to come into contact with the substrate, and forming a support part surrounding the pad at a portion where the sacrificial film is not formed on the substrate; Depositing a membrane on top of the sacrificial layer and the support and forming a contact groove to expose the pad to a predetermined portion of the membrane and the support; A third step of forming a plug in contact with the pad in the contact groove and applying a signal electrode to contact the plug on the membrane; Depositing a deformation portion on the surface of the signal electrode and patterning the signal electrode and the deformation portion so that only a portion corresponding to the support portion remains; Depositing an insulating film on an entire surface and patterning the insulating film and the membrane to expose the sacrificial film to separate the actuators; A sixth step of removing the sacrificial film by using the insulating film as a mask, filling the polymer layer in the space where the sacrificial film is removed, removing the insulating film on the deformed portion, and then forming a reflective film on the entire surface, and then removing the polymer layer Characterized in that consisting of.

In the sixth step, the filling of the polymer layer and forming the reflective film may include applying the polymer layer to the entire surface of the state where the sacrificial film is removed, and patterning the polymer layer so that only the insulating film on the deformed portion is exposed. Etching the exposed insulating film using a patterned polymer layer as a mask, removing the polymer layer existing on the remaining insulating film, and then applying a reflective film to the entire surface, and applying the reflective film only to the insulating film and the deformed portion. Patterning to exist.

In the sixth step, the filling of the polymer layer and forming the reflective film may include applying the polymer layer to the entire surface of the state where the sacrificial film is removed, and patterning the polymer layer so that only the insulating film on the deformed portion is exposed. Etching the exposed insulating film using a patterned polymer layer as a mask, removing the polymer layer existing on the remaining insulating film, and then patterning the insulating film so that the insulating film remains only on the sides of the deformable portion and the signal electrode. And a step of coating the reflective film on the entire surface and patterning the reflective film to exist only on the surfaces of the insulating film, the deformable portion, and the membrane.

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

2 (a) to (i) are cross-sectional views showing the manufacturing process of the optical path control apparatus according to an embodiment of the present invention.

First, a transistor (not shown) is embedded in a matrix form, and the sacrificial layer 35 is formed on the surface of the driving substrate 31 having the pad 33 electrically connected to each transistor thereon to a thickness of about 1 to 2 μm. Form. The sacrificial layer 35 is preferably formed of a metal material such as Mo, Cu, Fe, Ni, or PSG or polycrystalline silicon. When the sacrificial film 35 is formed of a metal material, the sacrificial film 35 may be formed by sputtering or spin coating. It is formed by CVD method when forming polycrystalline silicon by spin coating) method or CVD method. Thereafter, the sacrificial film 35 of the portion where the pad 33 is formed is removed by a conventional photolithography method to expose the pad 33 and the surrounding driving substrate 31, and then nitrided on the entire surface of the above structure. Silicates such as silicon (Si ₃ N ₄ ), silicon oxide (SiO ₂ ), or silicon carbide are deposited to a thickness of about 1 to 2 μm by sputtering or CVD, and then the sacrificial film ( By removing the silicide deposited on 35 to form the support 17, a structure as shown in Fig. 2A is obtained.

Subsequently, the same material as the support portion 37 is deposited on the entire surface of the structure described above by a thickness of about 0.7 to 2 탆 by sputtering or CVD to form the membrane 39. Thereafter, a contact groove penetrating the membrane 39 and the support portion 37 is formed in a predetermined portion on the pad 33, and then a conductive metal material such as tungsten (W) or titanium (Ti) is formed in the contact groove. Fill to form a plug 41 that is electrically connected to the pad 33. Subsequently, platinum (Pt) or platinum / titanium (Pt / Ti) or the like is applied to the entire surface of the structure by applying a signal electrode 43 with a thickness of about 500 to 2000 mV by vacuum deposition or sputtering. Form a structure as shown in b).

Next, piezoelectric ceramics such as BaTiO ₃ , PZT (Pb (Zr, Ti) O ₂ ) or PLZT ((Pb, La) (Zr, Ti) O ₂ ) or PMN are formed on the entire surface of the signal electrode 43. Electrodistortion ceramics such as (Pb (Mg, Nb) O ₂ ) are coated to a thickness of about 0.7 to 2 μm by the Sol-Gel method, the sputtering method, or the CVD method, and then the applied deformable portion 45 is sintered to Phase transformation is performed with a Perovskaite to form the deformation part 45. Subsequently, the signal electrode 43 and the deformable portion 25 are patterned using only the same mask so that only a portion corresponding to the support portion 17 remains. Next, silicon nitride (Si ₃ N ₄ ) serving as the insulating film 47 is deposited on the entire surface of the structure described above by a sputtering method, a CVD method, or the like to have a thickness of about 2000 to 5000 GPa, as shown in FIG. To form a structure as shown.

Subsequently, the insulating film 47 and the membrane 39 corresponding to the end opposite to the end of the sacrificial layer 35 directly under the deformation part 45 are removed by a conventional dry etching method or a wet etching method. The sacrificial layer 35 is exposed at that portion. Thereafter, the sacrificial film 35 is removed by a wet etching method using a solution such as HF or the like to form a structure as shown in FIG. At this time, since the insulating film 47 is coated on the entire surface of the deformation part 45, the deformation part 45 is not damaged by an etching solution such as HF.

Subsequently, the sacrificial layer was removed as shown in FIG. 3E by forming a polymer such as photoresist with a thickness of about 1 to 2 μm by spin coating at a very low rotational speed on the structure described above. In addition to filling the polymer layer 49 in the air gap, the polymer layer 49 may be applied to the insulating layer 47.

Next, the polymer layer 49 is patterned by a conventional photolithography method so that only the insulating film 47 on the deformable portion 45 is exposed, and then dry etching using the remaining polymer layer 49 as a mask. The exposed insulating film 47 is removed to form a structure as shown in FIG. 2 (f).

Subsequently, the polymer layer 49 remaining on the insulating film 47 is removed, so that the polymer layer 49 remains in the air gap. Subsequently, the reflective film 51 is formed by applying a material having good reflection and electrical properties such as silver (Ag) or aluminum to the entire surface to a thickness of about 500 to 2000 mW by sputtering or vacuum deposition. Form a structure such as

Thereafter, the reflective film 51 is patterned by a conventional photolithography method so that only the reflective film 51 existing above the membrane 39 remains, so that the polymer layer 49 as shown in FIG. To be exposed.

Subsequently, the polymer layer 49 filled in the air gap is removed by a plasma etching method using O ₂ to complete the actuator 50 as shown in FIG.

As described above, according to the exemplary embodiment of the present invention, the insulating film 47 is applied to the surface of the deformable portion 45 and the membrane 39 during the wet etching removal process of the sacrificial layer 35 in FIG. As a result, the deformable portion 45 is not damaged by the etching solution. In addition, the insulating layer 47 also functions to electrically isolate the reflective layer 29 and the signal electrode 23.

FIG. 3 is a cross-sectional perspective view showing the completed optical path adjusting device by the manufacturing method described with reference to FIG.

In the optical path adjusting device configured as described above, an image signal is applied to the signal electrode 43 electrically connected to the transistor of the driving substrate 31 via the plug 41 and the pad 33 and the reflecting film 51 is provided. As a bias voltage is applied to the electric field, an electric field is generated in the deformable part 45 interposed between the signal electrode 43 and the reflective film 51. Accordingly, the deformable part 45 expands in a direction perpendicular to the electric field. Since the contraction in the horizontal direction to generate a stress at the interface with the membrane 39, the deformation portion 45 is bent in the opposite direction of the membrane 39. Therefore, the membrane 39 on the support 37 is bent due to the strain difference from the deformation part 45, and the membrane 39 protruding on the support 37 is inclined flatly by the bending. The reflective film 51 is also inclined in the same manner as the membrane 39 to change the path of the incident light to reflect.

Next, a manufacturing method of an optical path control apparatus according to another embodiment of the present invention will be described with reference to FIGS. 4A to 4C.

In the present embodiment, the steps of FIGS. 2A to 3F are performed, and then the polymer layer 49 remaining on the insulating film 47 is removed. It remains inside. Thereafter, after the photoresist is applied to the entire surface, the photoresist is patterned so that the photoresist 61 remains only at a portion corresponding to the upper portion of the deformable portion 45 (FIG. 4A).

Subsequently, the insulating film 47 is etched by a dry etching method using the remaining photoresist 61 as a mask so that the insulating film 47A remains only on the side portions of the deformable portion 45 and the signal electrode 43. . At this time, since the polymer layer 49 is filled in the air gap below the membrane 39, it is possible to prevent stress at the membrane 39 during dry etching. Subsequently, a reflective film 51 is formed on the entire surface of the structure described above by applying a material having good reflection and electrical properties, such as silver or aluminum, to a thickness of about 500 to 2000 Pa by sputtering or vacuum deposition. (B)].

Next, the reflective film 51 is patterned by a conventional photolithography method so that only the reflective film 51 existing above the membrane 39 remains, so that the polymer layer 49 as shown in FIG. ) Is exposed.

Subsequently, similarly to FIG. 2 (i) described above, the polymer layer 49 filled in the air gap is removed by a plasma etching method using O ₂ to complete the actuator 50A (FIG. 4c).

As described above, according to another embodiment of the present invention, the insulating film 47 surrounds the sides of the deformable portion 45 and the membrane 39 during the wet etching removal process of the sacrificial layer 35 as in the above-described embodiment. Therefore, the deformed portion is not damaged by the etching solution. As shown in FIG. 4A, the polymer layer 49 is filled in the air gap below the membrane 39 in the removal process by dry etching the insulating film 47. You can prevent stress.

Claims (13)

A sacrificial layer 35 is formed on the driving substrate 31 formed on the surface of the pad 33 having a transistor embedded in a matrix and electrically connected to the transistor, and the substrate 31 is formed on the substrate 31. A first process of forming a support portion 37 surrounding the pad 33 in a portion where the sacrificial layer 35 is not formed, and the membrane 39 on the sacrificial layer 35 and the support portion 37. The second step of forming a contact groove so that the pad 33 is exposed to a predetermined portion of the membrane 39 and the support portion 37, the plug to contact the pad 33 inside the contact groove A third process of forming a 41 and applying the signal electrode 43 on the membrane 39 to be in contact with the plug 41 and depositing the deformable portion 45 on the surface of the signal electrode 43 is performed. And only the portion corresponding to the support portion 37 to the signal electrode 43 and the deformable portion 45 A fourth step of patterning to remain, the fifth step of depositing the insulating film 47 on the entire surface and patterning the insulating film 47 and the membrane 39 to expose the sacrificial film 35 to separate the actuator After the sacrificial layer 35 is removed using the insulating layer 47 as a mask, the polymer layer 49 is filled in the space where the sacrificial layer 35 is removed, and the insulating layer 47 on the deformable portion 45 is formed. And a sixth step of removing the polymer layer (49) after forming the reflective film (51) on the entire surface. The method of claim 1, wherein the sacrificial film (35) is formed of a metal of Mo, Cu, Fe, Ni by the sputtering method. The method of claim 1, wherein the sacrificial layer (35) forms PSG by spin coating or CVD. The method of claim 1, wherein the membrane (39) is formed of silicon oxide or silicon nitride by sputtering or CVD. The method of claim 1, wherein the signal electrode (43) is formed of platinum or platinum / titanium by vacuum deposition or sputtering. The method of claim 1, wherein the deformable portion (45) is formed of a piezoelectric ceramic or a total distortion ceramic by a Sol-Gel method, a sputtering method, or a CVD method. 7. The method of manufacturing an optical path control apparatus according to claim 6, comprising a step of applying the deformable portion (45) and then sintering. The method of manufacturing an optical path control apparatus according to claim 1, wherein said insulating film (47) forms silicon nitride by sputtering or CVD. The method of claim 1, wherein the filling of the polymer layer 49 and forming the reflective film 51 in the sixth step is a step of applying the polymer layer 49 to the entire surface of the state where the sacrificial film 35 is removed. And patterning the polymer layer 49 so that only the insulating film 47 on the deformable portion 45 is exposed, and etching the exposed insulating film 47 by using the patterned polymer layer 49 as a mask. And removing the polymer layer 49 existing on the remaining insulating film 47, and then applying the reflective film 51 to the entire surface of the insulating film 47 and only on the insulating film 47 and the deformable portion 45. Method for manufacturing an optical path control device, characterized in that consisting of a step of patterning to exist. The method of claim 1, wherein the filling of the polymer layer 49 and forming the reflective film 51 in the sixth step is a step of applying the polymer layer 49 to the entire surface of the state where the sacrificial film 35 is removed. And patterning the polymer layer 49 so that only the insulating film 47 on the deformable portion 45 is exposed, and etching the exposed insulating film 47 by using the patterned polymer layer 49 as a mask. After removing the polymer layer 49 existing on the remaining insulating layer 47, the insulating layer 47 is patterned, so that the insulating layer 47A remains only at the sides of the deformable portion 45 and the signal electrode 43. And a step of applying the reflective film 51 to the entire surface and patterning the reflective film 51 to exist only on the surfaces of the insulating film 47A, the deformable portion 45 and the membrane 39. Method of manufacturing an optical path control device. The method according to claim 9 or 10, wherein the polymer layer (49) forms a photoresist by spin coating. The method of manufacturing an optical path control apparatus according to claim 9 or 10, wherein the reflective film (51) is formed of silver (Ag) or aluminum by sputtering or vacuum deposition. The method of claim 1, wherein the polymer layer (49) is removed by a plasma etching method using O ₂ in the sixth step.