KR100220688B1 - Test pattern structure for thin film actuated mirror array - Google Patents

Abstract

The present invention relates to a method for confirming electrical connection by a plug metal of a lower electrode and a contact metal during a manufacturing process of a thin film optical path adjusting apparatus, A plurality of separated metal pads formed of a metal having electrical conductivity on the test die formed in a blank space in which N active elements are not formed; a passivation layer sequentially formed on the plurality of separated metal pads; The test pattern structure of the etch stop layer, the membrane, the lower electrode, and the plug metal connected to each of the separated plurality of metal pads through the passivation layer from the lower electrode, The reliability of the thin film type optical path adjusting device can be enhanced by easily confirming whether or not electrical connection is made by the plug metal of the contact metal.

Description

Test pattern structure for optical path control device

The present invention relates to a test pattern structure of an optical path adjusting apparatus used as a projection display apparatus, and more particularly, to a test pattern structure of a light path adjusting apparatus used as a projection display apparatus, in which a plug metal electrically connecting a lower electrode operating as a signal electrode and a contact metal of a driving substrate To a test pattern structure for an optical path adjusting device.

Generally, in an image display apparatus, a display apparatus is classified into a direct view type image display apparatus and a projection image display apparatus according to a display method.

The direct-view type image display device has a CRT (Cathode Ray Tude: hereinafter, referred to as 'CRT') or the like. Such a CRT image display device has good image quality, but as the screen size increases, the weight and thickness increase, There is a limitation in providing a large screen.

The projection-type image display apparatus includes a large-screen liquid crystal display (hereinafter referred to as LCD), and the weight of the large-screen LCD can be reduced.

However, since the loss of light due to the polarizing plate is large in such an LCD, and the thin film transistor for driving the LCD is formed for each pixel, the efficiency of light is very low because it has a limit to increase the aperture ratio (light transmission area).

Accordingly, a projection type image display device using an Actuated Mirror Arrays (hereinafter, referred to as 'AMA') has been developed.

The projection type image display apparatus using the AMA separates the white light emitted from the light source into red, high color and blue light, and then changes the optical path by driving the optical path adjusting apparatus including the actuators.

That is, the actuator is mounted on the actuators, and the actuators are individually driven to reflect mirrors, which are tilted, respectively, thereby changing the light path, thereby adjusting the amount of light and projecting the light 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 applied to the deformed portion made of piezoelectric or electrostrictive ceramics.

The AMA is classified into a one-dimensional AMA and a two-dimensional AMA according to the driving method. The one-dimensional AMA is a 1 < / RTI > array, and the two-dimensional AMA is arranged such that the mirrors are M N arrays. Therefore, the projection-type image display apparatus using the one-dimensional AMA is capable of displaying images of M A projection type image display apparatus employing a two-dimensional AMA and linearly scanning one light flux has M N light fluxes are projected to display an image.

Also, the actuator is divided into a bulk type and a thin film type according to the shape of the deformed portion. In the bulk type, a ceramic wafer, on which a metal electrode is formed by cutting a thin layer of a multilayer ceramic, is mounted on a driving substrate and then processed by sawing or the like, and a mirror is mounted.

However, since the bulk actuator needs to separate the actuators by sawing, a long process time is required and the response speed of the deformed part is slow.

Therefore, a thin film type actuator that can be manufactured using a semiconductor process has been developed.

FIG. 1 is a cross-sectional view of a unit pixel of a thin film type optical path controller having the above-described thin film type actuator. As shown in the figure, a silicon substrate 110 having active elements (not shown) A passivation layer 120 for preventing the active element from being physically and chemically damaged from the outside, and an etch stop layer 130 for preventing the passivation layer 120 from being damaged by a subsequent etching process It is possible to prevent electrical short between the driving substrate 100 and the plug metal 205, the upper electrode 240 and the lower electrode 220 for electrically connecting the lower electrode 220 and the contact metal 105 An insulating layer 207 and a membrane 210, a lower electrode 220, a deformed portion 230 and an upper electrode 240 are laminated in a predetermined shape to form a cantilever structure on the driving substrate 100 Actuate It consists of the emitter 200. The

However, in the conventional manufacturing method of the thin film type optical path adjusting device, since the plug metal 205 for electrically connecting the lower electrode 220 and the contact metal 105 is mounted in the vertically formed via hole, There is a problem that it is difficult to do.

It is an object of the present invention to provide a test structure for a thin film type optical path adjusting device capable of confirming whether electrical connection is made by a plug metal of a lower electrode and a contact metal during a manufacturing process of a thin film type optical path adjusting device .

In order to achieve the above object, the present invention provides a method of manufacturing a thin film optical path adjusting device, N is formed on a test die provided in a blank space in which active elements are not formed, the test pattern structure comprising: a plurality of metal pads formed of an electrically conductive metal on the test die; A passivation layer formed of an insulating material on top of the metal pad, an etch stop layer formed of nitride on the passivation layer, a membrane formed of silicon nitride on the etch stop layer, And a plug metal connected to each of the separated plurality of metal pads through the passivation layer in the lower electrode.

According to an embodiment of the present invention, the metal pad is made of tungsten (W).

According to an embodiment of the present invention, there is provided a method of fabricating a test pattern of a thin film type optical path adjusting device, wherein the metal pad is formed of platinum (Pt).

According to an embodiment of the present invention, there is provided a method of fabricating a test pattern of a thin film type optical path adjusting device, wherein the metal pad is made of titanium (Ti).

According to an embodiment of the present invention, the metal pad is made of tantalum (Ta).

According to an embodiment of the present invention, there is provided a method of fabricating a test pattern of a thin film type optical path adjusting device, wherein the metal pad is formed by a sputtering process.

According to another aspect of the present invention, there is provided a method of fabricating a test pattern for a thin film type optical path adjusting apparatus, wherein a plurality of layers of the test pattern are formed together with the respective layers of the thin film type optical path adjusting apparatus.

According to still another aspect of the present invention, there is provided a method of fabricating a test pattern of a thin film type optical path adjusting apparatus, wherein the test pattern is tested using a probe.

According to an embodiment of the present invention, the upper surface of the metal pad of the test pattern is exposed through a via hole.

FIG. 1 is a sectional view showing a cross section of a general optical path adjusting device. FIG.

FIG. 2 is a cross-sectional view schematically showing a wafer on which a test pattern structure according to the present invention is formed; FIG.

FIG. 3 is an enlarged plan view showing an enlarged view of the test pattern structure of FIG. 2; FIG.

4 is a cross-sectional view showing a cross section of a test pattern structure cut along the line I-I in FIG. 3;

DESCRIPTION OF THE REFERENCE NUMERALS

110: Silicon wafer 30: Test pattern structure

120: passivation layer 32: metal pad

130: etch stop layer 210: membrane

220: lower electrode 205: contact metal

110: driving substrate 200: actuator

101: active element 40: test die

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

FIG. 2 is an enlarged plan view of the test pattern structure of FIG. 2, and FIG. 4 is an enlarged plan view of the test pattern structure of FIG. 3 along the line I-I of FIG. Sectional view showing a cross section of the cut test pattern structure.

First, a test pattern structure 30 for a thin-film type optical path adjusting apparatus according to an embodiment of the present invention includes M Is formed on the test die 40 formed in the blank space in which the N active elements 101 are not formed.

A metal having electrical conductivity such as platinum (Pt), titanium (Ti), tantalum (Ta), tungsten (W) or the like is deposited on the test die by a sputtering process to form a plurality of layers A metal pad 32 for confirming whether or not electrical connection is established is formed.

The passivation layer 120 is formed in a blank space outside the portion where the actuator 200 of the driving substrate 100 is formed, in which active elements not shown in the figure are embedded in a matrix structure, An etch stop layer 130, a membrane 210, a lower electrode 220, and a plug metal 205.

The test pattern structure 30 for a thin film type optical path adjusting apparatus according to the present invention includes a plurality of actuators 200 when a plurality of actuators are formed in a predetermined shape by a plurality of deposition processes and etching processes on the driving substrate 100, Is formed in the margin space around the forming portion.

First, platinum (Pt), titanium (Ti), tantalum (Ta), or the like having electrical conductivity is stacked to a predetermined thickness by a sputtering process on the test die provided on the blank space to form a metal pad 32 .

On the other hand, a plurality of active devices 101 made of transistors such as MOSs are formed in a matrix structure on a silicon substrate 110 by a semiconductor integrated circuit manufacturing process. In a deposition process performed thereafter, In order to prevent the device from being exposed to chemical or physical damage from the outside, a passivation layer 120 for protecting the active device is formed by applying an insulating material to the silicon substrate 110 with a predetermined thickness by a deposition process At this time, the passivation layer 1200 is also formed on the metal pad 32.

Here, the insulating material may exhibit an insulating property for preventing a plurality of active elements (not shown) formed on the silicon substrate 110 from being electrically conducted to each other, The insulating material used to make such a characteristic requirement is composed of phosphorus-containing phosphosilicate glass (PSG) or borophosphosilicate glass (BPSG), which exhibits good flow characteristics at high temperatures. The deposition process for depositing the material consists of a chemical vapor deposition process (CVD).

The passivation layer 120 is etched using an etchant such as a hydrofluoric acid solution (HF) solution to form an actuator 200 having a unit pixel shape by patterning a plurality of actuators 200 in a cantilever structure. (HF) solution is deposited on the passivation layer 120 to a predetermined thickness by a vapor deposition process so that the etch stop layer 130 is formed on the passivation layer 120 so as to prevent chemical damage At this time, the etching stop layer 130 is also formed on the passivation layer 120 of the test pattern 30 in the same process.

Here, the insulating material constituting the etching stop layer 130 has a good silicon nitride (Si ₃ N ₄ ) composition which is not only excellent in insulating characteristics but also excellent in corrosion resistance to an etching solution HF solution as described above And the deposition process is performed by a chemical vapor deposition process (CVD), particularly a low pressure chemical vapor deposition process (LPCVD) or a plasma chemical vapor deposition process (PECVD).

That is, silicon oxide (PSG) or polycrystalline silicon containing phosphorus is deposited on the etch stop layer 130 to a predetermined thickness by a physical vapor deposition process (PVD) or a chemical vapor deposition process (CVD) to form a sacrificial layer a sacrificial layer (not shown) is formed, and then the sacrificial layer (not shown) is formed into a predetermined shape having a pattern of a predetermined line size by a fine pattern forming process. As a result, the sacrificial layer (not shown) A portion of the driving substrate 100 exposed through the pattern of the actuator 200 is provided as a place for forming the supporting portion and the bridge of the actuator 200. [

Since the structure of the test pattern 30 according to the present invention has the same structure as the support portion of the actuator 200 in which the high plug metal 205 is formed, the etch stop layer 130 are also completely removed.

As described above, the sacrificial layer (not shown) of a predetermined shape having a line width size of a predetermined pattern and the etch stop layer 130 exposed through the pattern of the sacrificial layer (not shown) are formed on the driving substrate 100, An insulating material having a good insulating property on a substrate and a good resistance to an etching solution such as a hydrofluoric acid (HF) solution is deposited to a predetermined thickness by a chemical vapor deposition process (CVD) to form a membrane 210, A membrane 210 is also formed on the etch stop layer 130 of the test pattern 30.

The insulating material constituting the membrane 210 is made of metal or silicon nitride (SiN _x ) having excellent resistance to withstand fatigue stress when the actuator of the actuator 200 having the cantilever structure is repeatedly tilted.

A conductive metal exhibiting good conductive characteristics such as platinum (Pt) or tantalum (Ta) is deposited on the membrane 210 to a predetermined thickness by a vacuum deposition process such as a sputter deposition process to form a lower electrode 220 The lower electrode 220 is connected to the contact metal 105 of the driving substrate 100 by a plug metal 205 to be formed in a subsequent process, And serve as signal electrodes by the electrical signals of the N active elements 101, respectively.

The lower electrode 220 is also formed on the membrane 210 of the test pattern 30 by the same process of forming the lower electrode 220 of the thin film optical path adjusting device.

A via hole is formed on the membrane 210 to expose the contact metal 105 electrically connected to the active element (not shown) built in the driving substrate 100 by a via hole forming process. A via hole is formed in the test pattern 30 so as to pass through the lower electrode 220 to the passivation layer 120 and to discharge the metal pad 32.

At this time, the upper surface of the metal pad 32 is exposed through the via hole, so that the exposed upper surface functions as an electrical contact surface with the plug metal 205.

Then, a plug metal 205 is formed by laminating a conductive metal such as titanium (Ti), platinum (Pt), or tantalum (Ta) to a predetermined thickness on the via hole by a lift off process, The lower electrode 220 receives the electrical signal of the active element by the plug metal 205 and operates as a signal electrode.

A plug metal 205 is also formed in the via hole formed in the test pattern 30 by the same process as the formation of the plug metal 205. The plug metal 205 is electrically connected to the lower electrode 220, (32) are electrically connected.

The lower electrode 220, the membrane 210, the etch stop layer 130, and the passivation layer 120, which are sequentially formed on the metal pad 32 of the test pattern 30, are subjected to anisotropic etching, (REACTION ION ETCH) to expose a portion of the metal pad 32.

Thereafter, when a probe is brought into contact with the exposed portions of the separated metal pads 32 and a voltage is applied thereto, if a current flows between the separated metal pads 32, the plug metal 205 is formed on the side of the via hole well .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. .

According to the present invention, N is formed in a blank space in which no active elements are formed, and a plurality of pseudo-lower electrodes, which are actuators of the thin-film type optical path adjusting device, are formed on the metal pads, A test pattern structure having the same structure as that of the plug metal formed in the via hole is formed and then the separated metal pad is checked for electrical continuity using a probe method to determine the formation state of the plug metal, .

Claims (4)

M A test pattern structure for a thin film type optical path adjusting apparatus formed on a test die provided in an empty space in which the active element is not formed among silicon substrates on which N (M, N is an integer) active elements are formed, A stacked metal pad in which a plurality of conductive metals are separated on an upper portion of the die; A passivation layer formed of an insulating material on the metal pad; An etch stop layer formed of nitride on the passivation layer; A membrane formed of silicon nitride on top of the etch stop layer; A lower electrode made of a metal having electrical conductivity on the membrane; And a plug metal which penetrates from the lower electrode to the passivation layer and is connected to each of the separated plurality of metal pads. The thin film optical path adjusting device according to claim 1, wherein the metal pad is formed by laminating any one of tungsten (W), platinum (Pt), titanium (Ti), and tantalum (Ta) Test pattern structure. The method of claim 1, wherein each of the plurality of layers of the test pattern comprises: And the thin film type optical path adjusting device is fabricated together with the same process as each layer of the thin film type optical path adjusting device. The test pattern structure of a thin film type optical path adjusting apparatus according to claim 1, wherein the test pattern is tested using a probe.