KR100252017B1 - Thin film actuated mirror array - Google Patents

Abstract

PURPOSE: A thin film type apparatus for controlling a light path is provided to prevent an image signal from not being transferred to a lower electrode by forming a pattern for a test to measure an electric characteristic of each member easily. CONSTITUTION: A driving substrate(510) has a built-in transistor. A protective layer(530) protects the driving substrate(510) to be damaged and is formed on the driving substrate(510) and a drain pad(520). An etching preventing layer(540) prevents the protective layer(530) from being damaged and is formed on the protective layer(530). An actuator comprises a membrane(560), a lower electrode(570), a strain layer(580), an upper electrode(590), a power distribution hole(610), a power distributor(620). The membrane(560) is intervened with an air gap(550) and formed in parallel with the etching preventive layer(540). The lower electrode(570) is supplied with an image signal from the drain pad(520). The strain layer(530) generates a strain in proportion to a bios voltage field. The upper electrode(590) approves a bios voltage and reflects a luminous flux incident from a light source. The power distribution hole(610) is formed vertically from the etching preventing layer(540) to the drain pad(520). The power distributor(620) connects the lower electrode(570) and the drain pad(520) electrically and enables an electric characteristic of each member to be measured easily.

Description

Thin Film Type Light Path Regulator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film type optical path adjusting device, and more particularly, to a thin film type optical path adjusting device capable of measuring the electrical characteristics of each member by extending both ends of a distributor electrically connecting the drain pad and the lower electrode of the driving substrate. will be.

In general, a spatial light modulator, which is an apparatus for projecting optical energy onto a screen, may be variously applied to optical communication, image processing, and information display apparatus. Such devices are classified into a direct view type image display device and a projection type image display device according to a method of projecting a light beam incident from a light source onto a screen. The direct view image display device includes a CRT (Cathod Ray Tube), and the projection image display device includes a liquid crystal display (hereinafter referred to as an LCD), a DMD (deformable mirror device), or an AMA (Actuated). Mirror Arrays).

The above-described CRT apparatus is an excellent display apparatus which is guaranteed an average brightness of 100 ft-L (white display) or more, a contrast ratio of 30: 1 or more, a lifetime of 10,000 hours or more. However, since the CRT has a large weight and volume and maintains high mechanical strength, it is difficult to make the screen completely flat, which causes distortion of the peripheral part. In addition, since CRTs excite phosphors with an electron beam to emit light, there is a problem that a high voltage is required to produce an image.

Therefore, LCDs have been developed to solve the above-mentioned problems of CRT. The advantages of such LCDs are explained in comparison with CRTs. LCDs operate at low voltages, consume less power, and provide images without distortion.

However, despite the above-mentioned advantages, the LCD has a low light efficiency of 1 to 2% due to the polarization of the light beam, and there is a problem that the response speed of the liquid crystal material therein is slow.

Accordingly, in order to solve the problems of the LCD as described above, a device such as a DMD or an AMA has been developed. Currently, AMA can achieve a light efficiency of 10% or more, while DMD has a light efficiency of about 5%. In addition, the AMA is not only affected by the polarity of the incident luminous flux but also does not affect the polarity of the luminous flux.

Typically, the respective actuators formed inside the AMA cause deformation depending on the electric field generated by the applied image signal and bias voltage. When this actuator causes deformation, each of the mirrors mounted on top of the actuator is inclined in proportion to the magnitude of the electric field.

Thus, these inclined mirrors can reflect light incident from the light source at a predetermined angle. Piezoelectric ceramics such as PZT (Pb (Zr, Ti) O ₃ ), or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as a constituent material of the actuator for driving the respective mirrors. As the constituent material of this actuator, electrodistorted ceramics such as PMN (Pb (Mg, Nb) O ₃ ) can be used.

The AMA is classified into a bulk type and a thin film type. Currently, AMA is the main trend of the thin-film optical path control device.

1 is a plan view of a conventional thin film type optical path control device, Figure 2 is a cross-sectional view taken along the line AA 'of the device shown in FIG.

Referring to FIG. 1, one side of the actuator 130 has a concave portion having a rectangular shape at the center thereof, and the concave portion is formed in a stepped shape toward both edges. The other side of the actuator 130 has a quadrangular protrusion which narrows down stepwise toward the center portion corresponding to the concave portion. Therefore, the concave portion of the actuator 130 is fitted into the protrusion of the neighboring actuator, and the protrusion of the actuator 130 is fitted into the concave portion of the neighboring actuator.

Referring to FIG. 2, the apparatus for controlling a thin film type optical path includes a driving substrate 10 having a drain pad 20 formed on one side thereof, and an actuator 60 formed thereon.

In the driving substrate 10, M × N (M and N are integer) transistors (not shown) are embedded in a matrix form. The protective layer 30 protects the driving substrate 10 from damage during the subsequent process and is formed on top of the driving substrate 10 and the drain pad 20, and the etch stop layer 40 is formed during the subsequent etching process. The protective layer 30 and its lower portion are protected from damage and are formed on the upper portion of the protective layer 30.

The actuator 130 is a membrane formed such that one side of the etch stop layer 40 is in contact with a portion where the drain pad 20 is formed, and the other side is parallel to the etch stop layer 40 through an air gap 50. (membrane: 60), formed on the upper portion of the membrane 60, the lower electrode 70 receives the image signal from the drain pad 20, formed on the lower electrode 70, deformed in proportion to the size of the electric field And a strained layer 80 formed on one side of the strained layer 80, and having a bias voltage applied thereto and reflecting a light beam incident from a light source. A distribution hole 110 vertically formed from the portion where the upper electrode 90 is not formed to the drain pad 20 through the membrane 60, the etch stop layer 40, and the protective layer 30, and the distribution hole 110. ) So that the lower electrode 70 and the drain pad 20 are electrically connected to each other. The ship includes a total 120.

However, the above-described conventional thin film type optical path control device measures the electrical characteristics of each member using the probe 140. In particular, the electrical characteristics of the optical path control device for each pixel, for example, the properties of the PZT constituting the strained layer 80 and the resistance of the distributor 120 by contacting the probe with the distributor 120 in the distribution hole 110. And leakage current and the like can be measured.

However, the power distribution hole 110 and the power distribution unit 120 therein of the conventional thin film type optical path control device are easily damaged by the probe 140, so that the drain pad 20 and the lower electrode 70 cannot be connected. There was a problem in that an image signal could not be transmitted to the lower electrode 70.

The present invention has been made to solve the conventional problems as described above, the object of the present invention is to extend the both sides of the distributor connecting the drain pad and the lower electrode to test patterns that are easy to measure the electrical characteristics of each member The present invention provides a thin film type optical path control apparatus capable of preventing the distribution of the power distribution unit in the distribution hole from being damaged by the probe and preventing the image signal from being transmitted to the lower electrode.

In order to achieve the above object, the present invention, M × N (M, N is an integer) is a transistor (not shown) is built in a matrix and the drain pad, the protective layer and the etch stop layer is sequentially formed on one side A substrate; A membrane formed such that one side of the etch stop layer is in contact with a portion where the drain pad is formed and the other side thereof is parallel to the etch stop layer through an air gap; A lower electrode formed on the membrane and receiving an image signal from a transistor of a driving substrate; A strained layer formed on an upper portion of the lower electrode in which the drain pad is not formed and causing deformation in proportion to the magnitude of the electric field; An upper electrode formed on the deformation layer and having a function of a mirror and a function of an electrode; A distribution hole formed vertically through the membrane, the etch stop layer, and the protective layer from a predetermined region in which the strained layer and the upper electrode are not formed in the lower electrode; A lower electrode and a drain pad are formed in the distribution hole so as to be electrically connected to each other, and a power distribution unit having a measurement area for measuring electrical characteristics of each device formed by extending above an exposed portion of the lower electrode is provided.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

1 is a plan view of a conventional thin film type optical path control device,

FIG. 2 is a cross-sectional view of the device of FIG. 1 taken along line AA '; FIG.

3 is a plan view of a thin film type optical path control apparatus according to the present invention,

4 is a cross-sectional view taken along line B-B 'of the apparatus of FIG.

5A to 5D are manufacturing process diagrams of the apparatus shown in FIG.

<Explanation of symbols for the main parts of the drawings>

510: driver board 520: drain pad

530: protective layer 540: etching prevention layer

550: air gap 560: membrane

570: lower electrode 580: strained layer

590: upper electrode 600: stripe

610: power distribution hole 620: power distribution

630: actuator 640: victim layer

Hereinafter, with reference to the accompanying drawings will be described in detail the thin-film optical path control apparatus according to the present invention.

FIG. 3 is a plan view of a conventional thin film type optical path control device, and FIG. 4 is a cross-sectional view taken along line B-B 'of the device shown in FIG.

Referring to FIG. 3, one side of the actuator 630 has a concave portion having a rectangular shape at the center thereof, and the concave portion is formed in a stepped shape toward both edges. The other side of the actuator 630 has a quadrangular protrusion that narrows stepwise toward the center portion corresponding to the concave portion. Therefore, protrusions of neighboring actuators are fitted into the concave portions of the actuator 630, and protrusions of the actuator 630 are fitted into the concave portions of the neighboring actuators.

Referring to FIG. 4, the thin film type optical path control apparatus includes a driving substrate 510 having a drain pad 520 formed on one side thereof, and an actuator 630 formed thereon.

In the driving substrate 510, M × N transistors (not shown) are embedded in a matrix form. The protective layer 530 is formed on top of the driving substrate 510 and the drain pad 520 to protect the driving substrate 510 from damage during a subsequent process, and the etch stop layer 540 is formed during the subsequent etching process. The protective layer 530 and its lower portion are protected from damage and are formed on the upper portion of the protective layer 530.

The actuator 630 may have a side in contact with a portion where the drain pad 520 is formed at the bottom of the etch stop layer 540, and the other side may be parallel to the etch stop layer 540 through the air gap 550. , A lower layer 570 formed on the membrane 560 and receiving an image signal from the drain pad 520, and formed on the lower electrode 570, and deforming in proportion to the magnitude of the electric field. 580, a strain layer 580 and an upper electrode 590, which are formed on one side of the strain layer 580, and which have a bias voltage applied thereto and reflect light beams incident from a light source. The distribution hole 610 vertically formed from the portion in which it is not formed to the drain pad 520 through the membrane 560, the etch stop layer 540, and the protective layer 530, and the lower electrode in the distribution hole 610. 570 and the drain pad 520 are electrically connected to each other, The side includes a distributor 620 extending above the lower electrode 570 on which the strained layer 580 and the upper electrode 590 are not formed, to facilitate measurement of electrical characteristics of each member.

Hereinafter, a method of manufacturing a thin film type optical path control apparatus according to the present invention will be described with reference to the drawings.

5A to 5D are manufacturing process diagrams of the apparatus shown in FIG. 4. 5A to 5D, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 5A, protection is made of Phospo Silicate Glass (PSG) on an upper portion of a driving substrate 510 having M × N transistors (not shown) and a drain pad 520 formed on one side thereof. Layer 530 is formed.

The protective layer 530 is formed to a thickness of about 1.0 to 2.0 μm by chemical vapor deposition (CVD). The protective layer 530 prevents the driving substrate 510 from being damaged during the subsequent process.

The etch stop layer 540 is formed of nitride on the passivation layer 530. The etch stop layer 540 is formed to have a thickness of about 1000 to 2000 kPa by a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 540 prevents the protective layer 530 and its lower portion from being damaged during the subsequent etching process.

The sacrificial layer 640 is formed on the etch stop layer 540. The sacrificial layer 640 is formed of in-silicate glass. The sacrificial layer 640 is formed to have a thickness of about 1.0 to 2.0 μm by atmospheric chemical vapor deposition (APCVD). In this case, since the sacrificial layer 640 covers the upper portion of the driving substrate 510 in which the transistor is embedded, the flatness of the surface thereof is very poor. Accordingly, the surface of the sacrificial layer 640 is planarized by using spin on glass (SOG) or chemical mechanical polishing (CMP). Subsequently, a portion of the sacrificial layer 640 in which the drain pad 520 is formed is etched to expose a portion of the etch stop layer 540.

Referring to FIG. 5B, the membrane 560 is formed of nitride on the exposed etch stop layer 540 and on the sacrificial layer 540. The membrane 560 is formed to have a thickness of about 0.1 to 1.0 μm by a low pressure chemical vapor deposition method.

The lower electrode 570 is formed of a metal such as platinum or platinum-tantalum on the membrane 560. The lower electrode 570 is formed to have a thickness of about 0.1 μm to about 1.0 μm by the sputtering method. The lower electrode 570 is provided with an image signal via the drain pad 520 from a transistor built in the driving substrate 510.

Referring to FIG. 5C, the strained layer 580 is formed of a piezoelectric material such as PZT or PZLT on the lower electrode 570. The strained layer 580 is formed to have a thickness of about 0.1 μm to 1.0 μm by a sol-gel method, a sputtering method, or a chemical vapor deposition (CVD) method. Subsequently, the strained layer 580 is phased by a rapid heat treatment (RTA) method.

The upper electrode 590 is formed of a metal having excellent electrical conductivity and reflectivity, for example, aluminum, platinum, or silver, on top of the strained layer 580. The upper electrode 590 is formed to have a thickness of about 0.1 to 1.0 μm by the sputtering method. The upper electrode 590 is applied with a bias voltage as a common electrode. Therefore, an electric field is generated between the upper electrode 590 and the lower electrode 570 to which the image signal is applied.

The stripe 600 is formed by patterning a predetermined portion of the upper electrode 590. The stripe 600 prevents diffuse reflection of the light beam incident from the light source by operating the upper electrode 590 uniformly.

Referring to FIG. 5D, the upper electrode 590 and the deformation layer 580 are patterned to have a predetermined shape to expose a predetermined portion of the lower electrode 570. As described above, the membrane 560, the etch stop layer 540, and the protective layer 530 are sequentially etched from a predetermined portion of the lower electrode 570 on which the upper electrode 590 and the strain layer 580 are exposed. The distribution hole 610 is vertically formed from the 570 to the drain pad 520.

The distributor 610 is formed of a metal having excellent electrical conductivity, for example, tungsten, platinum or titanium. The distributor 620 is formed such that the drain pad 520 is connected to the lower electrode 570 by a sputtering method. Therefore, the distributor 620 allows the image signal generated from the transistor of the driving substrate 510 to be transferred to the lower electrode via the drain pad 520 and the distributor 620.

Subsequently, both sides of the distributor 620 are extended to serve as a test pattern for measuring electrical characteristics of each member. Both sides of the distributor 620 are formed on the upper portion of the lower electrode 570 exposed by the lift-off method. Accordingly, the physical properties of the piezoelectric material constituting the strained layer 580 may be understood through both sides of the distributor 620, that is, the test pattern, and the internal electrical resistance and leakage current of the distributor 620 may be easily measured. . Because both sides of the distributor 620 extend, the electrical characteristics of each member can be measured without inserting the probe 140 shown in FIG. 2 into the distribution hole 610. In addition, both sides of the extended distribution 620 may prevent the distribution 620 in the distribution hole 610 from being damaged by the probe 140.

Subsequently, after the lower electrode 570 and the membrane 560 are patterned in sequence, the sacrificial layer 640 is removed by a dry etching method using hydrofluoric acid gas. Therefore, the air gap 550 is formed in the portion where the sacrificial layer 640 is removed to complete the thin film type optical path adjusting device.

As described above, the thin film type optical path adjusting device according to the present invention extends both sides of the power distributor connecting the drain pad and the lower electrode to form a test pattern which is easy to measure the electrical characteristics of each member. The electrical characteristics such as PZT resistance, via resistance, drain leak, etc. can be measured while the power supply is not damaged, and the effect of preventing the image signal from being transmitted to the lower electrode can be prevented. have.

As described above, although the present invention has been described with reference to the drawings, those skilled in the art may variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can.

Claims (3)

A driving substrate 510 in which M × N (M and N are integers) transistors (not shown) are formed in a matrix form and a drain pad 520, a protective layer 530, and an etch stop layer 540 are sequentially formed on one side thereof. )and; A membrane 560 formed at one side of the etch stop layer 540 in contact with a portion where the drain pad 520 is formed, and the other side thereof being parallel to the etch stop layer 540 via an air gap 550; A lower electrode 570 formed on the membrane 560 and receiving an image signal from a transistor of the driving substrate 510; A strained layer 580 formed on an upper portion of the lower electrode 570 in which the drain pad 520 is not formed and causing deformation in proportion to the magnitude of the electric field; An upper electrode 590 formed on the deformation layer 580 and having a function of a mirror and a function of an electrode; The membrane 560, the etch stop layer 540, and the protective layer 530 are vertically penetrated from a predetermined region in which the strained layer 580 and the upper electrode 590 are not formed in the lower electrode 570. A distribution hole 610 formed to be formed; The lower electrode 570 and the drain pad 520 are electrically connected to each other in the distribution hole 610, and the electrical characteristics of each device are formed to extend over the exposed portion of the lower electrode 570. Thin film type optical path control device having a distributor 620 having a measuring area for measuring the. The method of claim 1, wherein the protective layer 530 is made of a silicate glass, the etch stop layer 540 is made of nitride, the membrane 560 is made of nitride, the lower electrode 570 is Thin film type optical path control device is composed of platinum or platinum-tantalum, the strain layer (580) is made of a piezoelectric material, the upper electrode (590) is made of aluminum, platinum or silver. The apparatus of claim 1, wherein the distributor (620) is made of a metal of tungsten, platinum, aluminum, or titanium.

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