KR100255749B1 - Tma using ain and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A thin film type optical path adjusting device using an aluminium nitride(AIN) and a method for manufacturing the same are provided to simplify a process of manufacturing an actuator and prevent a driving substrate from being damaged by using AIN material and a low temperature process. CONSTITUTION: A protective layer(110) is formed on a substrate(100) having transistors and a drain pad(105) to prevent the substrate(100) from being damaged. An etching preventing layer(115) made of nitride is formed on the protective layer(110) to prevent the substrate(100) and the protective layer(110) from being damaged by an etching process. A sacrificial layer is formed on the etching preventing layer(115). A surface of the sacrificial layer is made flat by using a spin on glass or a chemical mechanical polishing method. A supporting unit of an actuator(160) is formed with partly exposing the etching preventing layer(115).

Description

Thin film type optical path control device using aluminum nitride and manufacturing method thereof

The present invention relates to a thin-film optical path control device, and more particularly, it is possible to simplify the manufacturing process of the actuator by using aluminum nitride (AlN) material that satisfies the piezoelectric and support characteristics of the actuator at the same time, the driving substrate by a low temperature process The present invention relates to a thin-film optical path control apparatus and a method for manufacturing the same, which can prevent damage of the film.

In general, an optical path control device capable of forming an image by adjusting a light flux is a direct view type image display device such as a CRT (Cathod Ray Tube) or a projection type image display device according to a method of projecting a light beam incident from a light source on a screen. Liquid crystal displays (hereinafter referred to as "LCD"), DMD (Deformable Mirror Device), AMA (Actuated Mirror Arrays) and the like.

Although CRT devices have excellent image quality, as the screen size increases, the weight and volume of the device increase, and the manufacturing cost thereof increases. In contrast, a liquid crystal display (LCD) can be formed into a flat plate, but the incident light flux Due to the polarization of the light having a low light efficiency of 1 to 2%, there was 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. This thin film type optical path control device is disclosed in the prior art of Patent Application No. 96-59191 filed by the applicant of the Korean Patent Office on November 28, 1996.

1 is a plan view of a thin film type optical path adjusting device described in the prior application, Figure 2 is a cross-sectional view taken along the line AA 'of FIG.

1, 2 and 3, the thin film type optical path adjusting device described by the prior application includes a substrate 5 and an actuator 65 formed thereon.

The actuator 65 has a cantilever shape in which one side is supported at a portion where the drain pad 10 is formed below, and includes a membrane 30, a lower electrode 35, a strained layer 40, and an upper electrode 45. The via contact 55 includes a via contact 55 vertically formed to the drain pad 10 so that the drain pad 10 and the lower electrode 35 are electrically connected to each other.

One side of the planar shape of the actuator 65 has a rectangular concave portion at the center thereof, and the concave portion is formed in a shape widening stepwise toward both edges. The other side of the actuator 65 has a quadrangular protrusion that narrows in a stepped manner toward the central portion corresponding to the concave portion. Therefore, the concave portion of the actuator 65 adjacent to the concave portion of the actuator 65 is fitted, and the rectangular projection is fitted to the concave portion of the adjacent actuator 65.

In the conventional thin film type optical path adjusting device, when an image signal voltage is applied to the lower electrode 35, which is a signal electrode, and a bias voltage is applied to the upper electrode 45, which is a common electrode, the upper electrode 45 and the lower electrode 35 are applied. An electric field is generated between them. The deformed layer 40 between the upper electrode 45 and the lower electrode 35 causes deformation by the electric field, and the deformed layer 40 contracts in a direction perpendicular to the electric field. Accordingly, the actuator 65 including the deformation layer 40 is bent at a predetermined angle, and the mirror 60 mounted on the upper electrode 45 of the actuator 65 is bent by the bent upper electrode 45. The axis is moved and tilted to reflect the light beam incident from the light source. The light beam reflected by the mirror 60 is projected onto the screen through the slit to form an image.

In order to manufacture the above-described thin film type optical path control device, a protective layer 15 and an etch stop layer 20 are formed on an upper portion of a substrate 5 having M × N transistors embedded in a matrix and having a drain pad 10 formed on one side thereof. And a sacrificial layer (not shown) is formed thereon.

A portion of the sacrificial layer in which the drain pad 10 is formed is etched to expose a portion of the etch stop layer 20, and the membrane 30 is disposed on the top of the exposed etch stop layer 20 and the sacrificial layer. To form. The membrane 30 is formed to have a thickness of about 0.1 ~ 1.0㎛ by a low pressure chemical vapor deposition method at a temperature of about 800 ℃.

The lower electrode 35 formed of platinum (Pt) or tantalum (Ta) thereon is formed to a thickness of about 500 to 2000 kPa by a sputtering method at a temperature of about 350 ° C.

The strained layer 40 formed of PZT or PLZT, which is a piezoelectric material, is formed to have a thickness of 0.1 to 1.0 μm by a sol-gel method. Subsequently, the strained layer 40 is thermally transformed by rapid thermal annealing (RTA) at a temperature of about 650 ° C.

The upper electrode 45 formed of aluminum or platinum, which is a metal having excellent electrical conductivity and reflectivity, is formed to have a thickness of about 500 to 2000 Pa by sputtering at a temperature of about 350 ° C.

Subsequently, the via holes 50 are formed by vertical etching from the strained layer 40 to the upper portion of the drain pad 10, and metals such as tungsten, platinum, or titanium are formed by a lift-off method to drain the pads. A via contact 55 is formed to electrically connect the 10 and the lower electrode 35.

Subsequently, the strained layer 40, the lower electrode 35, and the membrane 30 are sequentially patterned in cell units, and then the sacrificial layer is removed with hydrofluoric acid to complete the manufacturing process of the optical path control apparatus.

However, as described above, the conventional optical path control device requires an appropriate process temperature in order to form each layer of the actuator 65, and in particular, a process atmosphere of about 800 ° C. is required to form a membrane. This high temperature could damage the substrate on which the transistor is embedded.

In addition, each layer of the actuator is made of a different material to perform a unique function, and to deposit such materials, according to the characteristics of the deposition material, the appropriate process and apparatus are used. The process atmosphere of the apparatus, for example, the vacuum atmosphere, must be re-equipped each time. This is likely to cause defects such as inflow of impurities due to frequent movement of the substrate, increases the process cost of performing various deposition processes, and has the disadvantage of delaying the process time.

The present invention is to solve the above conventional problems, it is possible to simplify the manufacturing process of the actuator by using aluminum nitride (AlN) material that satisfies the piezoelectric and support characteristics of the actuator at the same time, the driving substrate by a low temperature process It is an object of the present invention to provide a thin film-type optical path control device and a method for manufacturing the same that can prevent damage of the.

In order to achieve the above object, the present invention provides a sacrificial layer formed on a substrate having M × N (M, N is an integer) transistors and a drain pad formed on one side thereof, and using aluminum nitride (AlN) thereon. A membrane, a lower electrode made of aluminum (Al), a strained layer made of aluminum nitride (AlN), and an upper electrode made of aluminum (Al) are sequentially deposited to form an actuator having a cantilever shape, and an image signal voltage is applied to the actuator. Forming a via contact for applying a, and removing the sacrificial layer provides a method of manufacturing a thin film type optical path control apparatus.

According to another object of the present invention, there is provided a substrate in which M × N (M, N is an integer) transistors are built and a drain pad is formed on one side thereof; A cantilever-shaped actuator having a membrane made of aluminum nitride (AlN), a lower electrode made of aluminum (Al), a strained layer made of aluminum nitride (AlN), and an upper electrode made of aluminum (Al); ; Provided is a thin film type optical path control apparatus including a via contact electrically connecting the upper electrode and the drain pad to apply an image signal voltage to the actuator.

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 thin film type optical path control device according to the applicant's prior application,

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

Figure 3a to 3c is a manufacturing process diagram of a thin film type optical path control apparatus according to the present invention.

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

100: substrate 105: drain pad

110: protective layer 115: etch stop layer

120: victim 125: air gap

130: membrane 135: lower electrode

140: deformation layer 145: upper electrode

150: Via Hole 155: Via Contact

160: Actuator

Hereinafter, a thin film type optical path adjusting apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 3, the optical path control apparatus according to the present invention includes a substrate 100 and an actuator 160 formed on the substrate 100. The substrate 100 is disposed on the drain pad 105 formed on one side of the substrate 100, the protective layer 110 and the protective layer 110 stacked on the substrate 100 and the drain pad 105. The stacked etch stop layer 115 is included.

The actuator 160 is formed of aluminum nitride (AlN) on a substrate 100 having M × N (M, N is an integer) transistors and a drain pad 105 formed on one side thereof. A lower electrode 135 made of (Al), a strained layer 140 made of aluminum nitride (AlN), and an upper electrode 145 made of aluminum (Al), and applying an image signal voltage to the actuator 160. To include the via contact 155 to electrically connect the upper electrode 145 and the drain pad 105.

Hereinafter, the manufacturing method of the thin film type optical path control device according to the present invention will be described in detail.

3A to 3C show a manufacturing process diagram of a thin film type optical path control apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 3A, a protective layer 110 of silicate glass (PSG) material is formed on an upper portion of a substrate 100 having M × N transistors embedded in a matrix and having a drain pad 105 formed on one side thereof. To form. The protective layer 110 is formed to have a thickness of about 1.0 to 2.0 μm using a chemical vapor deposition (CVD) method. The protective layer 110 prevents damage to the substrate 100 in which the transistor is embedded during subsequent processing.

An etch stop layer 115 made of nitride is formed on the passivation layer 110. The etch stop layer 115 is formed to have a thickness of about 1000 to 2000 kPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 115 prevents the substrate 100 and the protective layer 110 from being damaged by the subsequent etching process.

The sacrificial layer 120 is formed on the etch stop layer 115. The sacrificial layer 120 is formed of a silicate glass (PSG) to have a thickness of about 0.5 to 4.0㎛ by the atmospheric pressure chemical vapor deposition (APCVD) method. In this case, since the sacrificial layer 120 covers the upper portion of the substrate 100 in which the transistor is embedded, the flatness of the surface thereof is very poor. Therefore, the surface of the sacrificial layer 120 is planarized by using a spin on glass (SOG) method or a chemical mechanical polishing (CMP) method. Subsequently, a portion of the sacrificial layer 120 in which the drain pad 105 is formed is etched to expose a portion of the etch stop layer 115 to form a portion in which the supporting portion of the actuator 160 is to be formed.

Referring to FIG. 3B, the membrane 130 is formed on the exposed etch stop layer 115 and on the sacrificial layer 120. The membrane 130 is formed to have a thickness of about 0.1 to 1.0 μm at a low temperature process condition of about 200 ° C. by sputtering of aluminum nitride (AlN). The Young's modulus of the aluminum nitride (AlN) is 350 kN / mm 2, which is more excellent than the nitride used for the membrane, for example, Si ₃ N ₄ (elastic modulus 310 kN / mm 2).

Subsequently, the lower electrode 135 formed of aluminum (Al) metal having excellent electrical conductivity on the membrane 130 is formed to a thickness of about 500 to 2000 Pa by sputtering while maintaining a process temperature of about 150 ° C. or less. The lower electrode 135 receives an image signal from the transistor embedded in the driving substrate 100 via the drain pad 105 and the via hole 150 as a signal electrode.

Subsequently, the strained layer 140 formed of aluminum nitride (AlN), which is a piezoelectric material, is formed on the lower electrode 135 to have a thickness of 0.1 to 1.0 μm by a sputtering method while maintaining a process temperature of 200 ° C. or less.

Subsequently, aluminum having excellent electrical conductivity and reflective properties is formed on the strained layer 140 so as to have a thickness of about 500 to 2000 Pa while maintaining a process temperature of about 150 ° C. in the sputtering method. The upper electrode 145 is applied with a bias voltage as a common electrode to generate an electric field between the lower electrode 135 and the upper electrode 145. Therefore, the strained layer 140 is deformed in proportion to the size of the electric field described above to change the path of the light beam through which the upper electrode 145 is incident from the light source.

On the other hand, each layer of the actuator 160 deposited by the prior process, the membrane 130 is made of aluminum nitride (AlN), the lower electrode 135 is made of aluminum (Al), the deformation layer 140 is Since it is made of aluminum nitride (AlN) and the upper electrode 145 is made of aluminum (Al), both of the nitrogen (N) and aluminum (Al), it is possible to continuously deposit in one sputtering device. That is, the aluminum target is mounted on the sputtering apparatus, and reactive sputtering is performed by injecting nitrogen gas while maintaining an appropriate vacuum degree to deposit a membrane 130 made of aluminum nitride (AlN), and continuously depositing only aluminum to lower the electrode ( 145 is formed, and a similar process is performed to form the deformation layer 140 made of aluminum nitride (AlN) and the upper electrode 145 made of aluminum (Al).

Referring to FIG. 6C, the strained layer 140, the lower electrode 135, the membrane 130, the etch stop layer 115, and the protective layer 110 are formed from a portion of the strained layer 140 in which the drain pad 105 is formed. After etching sequentially to form the via hole 150, the drain pad 105 and the lower electrode 135 is electrically connected to the inside of the via hole 150 by sputtering a metal such as tungsten, platinum, aluminum, or titanium. The via contact 155 is formed to be connected to each other. The via contact 155 is formed vertically from the lower electrode 135 to the top of the drain pad 105 in the via hole 150. Accordingly, the image signal is applied to the lower electrode 135 through the drain pad 105 and the via contact 155 from the transistor embedded in the substrate 100.

Subsequently, the strained layer 140, the lower electrode 135, and the membrane 130 are sequentially patterned, and then the sacrificial layer 120 is removed with hydrofluoric acid to form an air gap 125.

As described above, after completing the device of the thin film type AMA, platinum-tantalum (Pt-Ta) is deposited on the lower end of the driving substrate 100 using a sputtering method to form an ohmic contact (not shown).

Next, after applying a photoresist (not shown) on the driving substrate 100, a tape carrier package for applying a bias voltage to the upper electrode 145 and an image signal to the lower electrode 135. (Not shown) The driving substrate 100 is cut to have a predetermined thickness in preparation for bonding.

Subsequently, the pad portion of the AMA panel is etched using a dry etching method to expose the pad (not shown) of the AMA panel required for TCP bonding.

As described above, the driving substrate 100 on which the thin film type AMA element is formed is completely cut into a predetermined shape, and then the pad of the AMA panel and the TCP are connected to complete the manufacture of the thin film type AMA module.

In the above description, it should be understood that those skilled in the art can make modifications and changes to the present invention without changing the gist of the present invention as it merely illustrates a preferred embodiment of the present invention.

As described above, the thin film type optical path control device according to the present invention can perform the deposition process continuously while controlling the component ratio in one device by simplifying the material of each layer constituting the actuator with aluminum (Al) or aluminum nitride (AlN). Therefore, it is possible to proceed without breaking the process atmosphere once set, for example, vacuum, and to minimize the movement of the substrate to prevent substrate defects due to impurities, etc., the deposition of all layers forming the actuator is 200 Since it is made at a low temperature of less than ℃ ℃ can bring about the effect of preventing the deterioration of the characteristics of the driving substrate with a built-in transistor.

Claims (3)

Forming a sacrificial layer on a substrate having M × N (M, N is an integer) transistors formed therein and a drain pad formed on one side thereof; An actuator is formed by sequentially depositing a membrane made of aluminum nitride (AlN), a lower electrode made of aluminum (Al), a strained layer made of aluminum nitride (AlN), and an upper electrode made of aluminum (Al) on the sacrificial layer. Making a step; Forming a via contact for applying an image signal voltage to the actuator; Method of manufacturing a thin film type optical path control device comprising the step of removing the sacrificial layer. The method of manufacturing a thin film type optical path control apparatus according to claim 1, wherein the step of forming the actuator is performed at a temperature of 200 deg. A substrate having M × N (M, N is an integer) transistors formed therein and a drain pad formed on one side thereof; A cantilever-shaped actuator having a membrane made of aluminum nitride (AlN), a lower electrode made of aluminum (Al), a strained layer made of aluminum nitride (AlN), and an upper electrode made of aluminum (Al); ; And a via contact electrically connecting the upper electrode and the drain pad to apply an image signal voltage to the actuator.

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