KR19990070662A - Rocker-arm type polysilicon structure layer and its manufacturing method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilicon structure layer and a method of manufacturing the same, and in particular, comprising a rocker-arm of a polysilicon layer capable of rocking movement up and down supported by grooves formed in a silicon substrate layer by a silicon etching process. The present invention relates to a rocker-arm type polycrystalline silicon structure layer and a method of manufacturing the same. According to the present invention, a digital micromirror device that does not require a hinge structure can be implemented as a micromechanical system, which not only simplifies the process but also significantly improves durability, has a smaller size, and a smaller driving voltage. Digital micrometer devices can be manufactured.

Description

Rocker-arm type polysilicon structure layer and its manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilicon structure layer and a method of manufacturing the same, and in particular, comprising a rocker-arm of a polysilicon layer capable of rocking movement up and down supported by grooves formed in a silicon substrate layer by a silicon etching process. The present invention relates to a rocker-arm type polycrystalline silicon structure layer and a method of manufacturing the same.

Polycrystalline silicon structure layers formed by semiconductor fabrication techniques, such as by depositing, patterning and etching highly conductive polycrystalline silicon on a silicon substrate, are particularly used for producing micromechanical systems, also called micromachining systems.

The present invention also provides a polysilicon structure layer including a rocker-arm of a polysilicon layer that can be rocked up and down, supported by grooves formed in the silicon substrate layer, even in the polycrystalline silicon structure layer implementing such a micromechanical system. And to provide a method of manufacturing the same.

The rocker-arm type polysilicon structure layer proposed in the present invention can be applied to a digital micromirror device.

Conventional digital micromirror devices have been developed in which a digital micromirror array is used as a display device for an HDTV. A single digital micromirror has a width and height in micrometers and is written in a CMOS SRAM fabricated on the floor of a mirror. By tilting left or right with information of '0' or '1', the device can selectively reflect the RGB light incident on the mirror on the large screen. The digital micromirror array device is not only brighter than LCD, but also has a small driving voltage of 5V and is suitable for large screens.

Conventional digital micromirror devices require a hinge structure that supports the mirror surface to tilt the mirror surface left or right. This hinge structure is a major factor in the durability of the digital micromirror.

The present invention is to provide a rocker-arm type polysilicon structure layer that is more durable than the conventional digital micrometer device by implementing a digital micrometer device without a hinge structure as a micromechanical system and can simplify the manufacturing process.

The present invention also provides a rocker-arm type polysilicon structure layer that can be applied to implement a digital micrometer device having a smaller size and smaller driving voltage than a conventional digital micrometer device.

It is still another object of the present invention to provide a method for producing a rocker-arm type polycrystalline silicon structure layer.

1 is a plan view of a rocker-arm type polysilicon structure layer according to the present invention;

FIG. 2 is a front view of the AA ′ cross section of the rocker-arm type polysilicon structure layer according to the present invention shown in FIG. 1;

3 is an operating state diagram of a rocker-arm type polysilicon structure according to the present invention;

4 is a flowchart of a method for producing a rocker-arm type polysilicon structure according to the present invention;

FIG. 5 is a mask pattern used in the manufacturing process shown in FIG. 4; FIG.

Explanation of symbols on the main parts of the drawings

1: silicon substrate 2: nitride film

3: first polysilicon layer 4: first oxide film

5: second oxide film 6: second polycrystalline silicon layer

7: metal film

10: groove 20: rocker-arm

30: protrusion

In order to achieve the object as described above, the rocker-arm type polysilicon structure layer according to the present invention comprises a groove formed in the silicon substrate layer; And a rocker-arm of a polysilicon layer that is supported by the groove and capable of rocking up and down.

In addition, the method for producing a rocker-arm type polysilicon structure layer according to the present invention includes a first step of forming a nitride film layer on a silicon substrate; A second step of forming a first polycrystalline silicon layer on the nitride film formed in the first step and patterning a recessed portion in the first polycrystalline silicon layer; A third step of forming a first oxide layer on the first polysilicon layer patterned in the second step; Patterning the first oxide layer to form protrusions of the rocker-arm; A fifth step of patterning groove portions of the first oxide layer to form grooves in the silicon substrate; Etching the silicon substrate to form grooves in the silicon substrate; A seventh step of forming a second oxide film on the structure layer in which the groove is formed in the sixth step; An eighth step of forming a second polysilicon layer on the structure layer on which the second oxide film layer is formed in the seventh step; A ninth step of patterning the second polysilicon structure layer formed in the eighth step; And a tenth step of completing the rocker-arm structure by removing the first oxide layer and the second oxide layer by sacrificial etching from the structure layer having undergone the ninth step.

Hereinafter, a rocker-arm type polycrystalline silicon structure layer and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view before the first oxide film 4 and the second oxide film 5 are sacrificially etched in the rocker-arm type polysilicon structure layer according to the present invention, and FIG. 2 is according to the present invention shown in FIG. Front view of the AA 'cross section of the rocker-arm type polysilicon structure layer. 3 is an operational state diagram of a rocker-arm type polysilicon structure according to the present invention.

As shown in FIG. 3, the polysilicon structure layer according to the present invention is locked by a groove 10 and a groove 10 formed by etching the silicon substrate 1 and supported by the groove 10 to be shaken up and down. The rocker-arm 20 to be made an essential component. The rocker-arm 20 is formed of the second polycrystalline silicon layer 6, and, if necessary, a metal film 7 may be formed on the second polycrystalline silicon layer, for example, to implement a digital micromirror.

The nitride film 2 formed on the silicon substrate 1 serves as an insulator, and the first polycrystalline silicon layer 3 formed on the nitride film 2 and the second polycrystalline silicon layer 6 forming the rocker-arm are flat plates. Configure the capacitor.

When a suitable power source is applied to the first polysilicon layer 3, the rocker-arm 20 by the second polysilicon layer 6 is pivoted so that the mirror plate can be driven to swing up and down.

When the polysilicon structure layer shown in Fig. 3 is applied to the digital micromirror, the rocker-arm 20 can tilt the digital micromirror to the left or the right by the rocking motion of shaking up and down. It can be selectively reflected on a large screen.

At this time, since the rocker-arm is supported by the groove in the structure according to the present invention, a separate hinge structure for supporting the mirror surface is not necessary. In the structure according to the present invention, the groove supports the rocker-arm so that the mirror plate is not separated from the silicon substrate when the rocker-arm moves up and down without a separate hinge structure. To this end, the shape of the groove on the silicon substrate in the structural layer according to the present invention is narrowed toward the upper layer of the silicon substrate, as shown in Fig. 3 so that the rocker-arm is supported without being separated by the groove edge of the surface of the silicon substrate. do.

In addition, the driving power supply is about 1V, which is smaller than 5V in the conventional digital micromirror, thereby simplifying the driving circuit.

In addition, the rocker-arm type polysilicon structure layer according to the present invention includes a protrusion 30 for preventing the electrodes from shorting during the locking motion of the rocker-arm 20 as described above.

FIG. 4 is a process diagram of a method for manufacturing a rocker-arm type polysilicon structure layer according to the present invention embodied as a digital micromirror, and FIG. 5 is a mask pattern used in the fabrication process shown in FIG.

As shown in Fig. 4, the rocker-arm type polysilicon structure layer according to the present invention forms the nitride film 2 on the silicon substrate 1 and later etches the silicon substrate 1 to form grooves. It begins with the first step of patterning the nitride film 2 (Fig. 4A). The mask pattern used to pattern the nitride film 2 at this time is shown in FIG. 5A.

Then, the first polysilicon layer 3 is formed on the nitride film 2 formed and patterned in the first step, doped with a conductive material, and patterned (second step: FIG. 4B). The mask pattern used to pattern the first polysilicon layer 3 at this time is shown in FIG. 5B.

A first oxide layer 4 is formed on the first polysilicon layer 3 patterned in the second step (Step 3: FIG. 4C), and the first oxide layer 4 formed in the third step is flattened. The first oxide layer 4 is patterned to form the protrusion 30 of the rocker-arm (FIG. 4E). The mask pattern used to pattern the first oxide layer 4 at this time is shown in FIG. 5C.

Later, the first oxide layer 4 is patterned to etch the silicon substrate 1 to form grooves (fifth step: Fig. 4F). At this time, the first oxide film layer 4 uses the same mask pattern as that used to pattern the nitride film layer 2 (Fig. 5A).

The silicon substrate 1 is etched to form grooves 10 in the silicon substrate 1 (sixth step: Fig. 4G). At this time, the etching of the silicon substrate 1 is preferably used a plasma etching technique which is a dry etching method. The formed groove 10 is narrowed toward the surface of the silicon substrate 1 to have an easy shape for supporting the rocker-arm 20 by the groove edge of the surface of the silicon substrate 1.

In the sixth step, the second oxide film 5 is formed on the structure layer in which the recess is formed (step 7: FIG. 4H).

In order to form the second polysilicon layer 6 on the structure layer on which the second oxide layer 5 is formed in the seventh step, doping with a conductive material (step 8: FIG. 4i), and implementing it as a digital micromirror, A metal film layer 7 is formed (ninth step: Fig. 4J).

The second polysilicon layer 6 and the metal film layer 7 formed in the eighth step are patterned (step 10: FIG. 4K). The mask pattern used at this time is shown in Fig. 5D.

The first oxide layer 4 and the second oxide layer 5 are removed by sacrificial etching from the structure layer having undergone the tenth step to complete the rocker-arm 20 and the protrusions 30 (step 11: 4L).

In the completed rocker-arm type polysilicon structure layer, the first polysilicon layer 3 can be driven by power, an example of which is shown in FIG. 5B. As shown in FIG. 5B, when power is applied to the positive electrode and the negative electrode of the first polysilicon layer 3, the second polysilicon layer 6 and the metal film layer 7 as shown in FIG. 5D can be driven. have.

As shown in FIG. 5B, the first polysilicon layer 3 has another electrode GND 'which can be used as ground, in addition to the electrode GND which can be used as the ground of the positive electrode and the negative electrode. This extra electrode can also be used as another ground electrode (GND ') that eliminates stray charges unnecessary for driving the device.

As described above, the present invention provides a rocker-arm type polycrystalline silicon structure layer and a manufacturing method thereof as a micromechanical system. According to the present invention, a digital micromirror device that does not require a hinge structure can be implemented as a micromechanical system, which not only simplifies the process but also significantly improves durability, has a smaller size, and a smaller driving voltage. Digital micrometer devices can be manufactured.

Claims (8)

In the polysilicon structure layer, Grooves formed in the silicon substrate layer; And The rocker-arm type polysilicon structure layer, characterized in that it comprises a rocker-arm of the polycrystalline silicon layer that is supported by the groove and capable of rocking movement up and down. The method of claim 1, wherein the groove, A rocker-arm type polysilicon structure layer, wherein the rocker-arm is narrowed toward the upper layer of the silicon substrate so that the rocker-arm is supported without being separated by the groove edge of the surface of the silicon substrate. The method of claim 1, wherein the structural layer, The rocker-arm type polysilicon structure layer, characterized in that it comprises a protrusion for preventing the short circuit of the electrode during the rocking motion of the rocker-arm polycrystalline silicon layer of the rocker-arm. The rocker-arm type according to any one of claims 1 to 3, wherein a metal film is formed on the rocker-arm of the polycrystalline silicon layer so that the polycrystalline silicon structure layer is implemented as a digital micromirror device. Polycrystalline silicon structure layer. In the method for producing a polysilicon structure layer, Forming a first polycrystalline silicon layer insulated from the silicon substrate by an insulating film; Etching the silicon substrate to form grooves that narrow toward the upper layer of the silicon substrate; And Forming a second polycrystalline silicon layer having a rocker-arm structure supported by the groove. The method of claim 5, wherein the polysilicon structure layer is manufactured by A first step of forming a nitride film layer on a silicon substrate and patterning the nitride film to form grooves in the silicon substrate; A second step of forming and patterning a first polycrystalline silicon layer on the nitride film formed and patterned in the first step; A third step of forming a first oxide layer on the first polysilicon layer patterned in the second step; Patterning the first oxide layer to form protrusions of the rocker-arm; A fifth step of patterning the first oxide layer to form grooves in a silicon substrate; Etching the silicon substrate to form grooves in the silicon substrate; A seventh step of forming a second oxide film on the structure layer in which the groove is formed in the sixth step; An eighth step of forming a second polysilicon layer on the structure layer on which the second oxide film layer is formed in the seventh step; A ninth step of patterning the second polysilicon structure layer formed in the eighth step; And And a rocker-arm type polycrystalline silicon structure layer comprising the tenth step of completing the rocker-arm structure by removing the first oxide layer and the second oxide layer by sacrificial etching from the structure layer having undergone the ninth step. Manufacturing method. 7. The method of claim 6, wherein the etching of the silicon substrate in the sixth step uses a plasma etching technique, which is a dry etching method. The method for producing the polycrystalline silicon structure layer according to any one of claims 5 to 7, The method may further include forming a metal layer on the second polysilicon structure layer formed in the eighth step, and simultaneously patterning the second polysilicon structure layer and the metal layer in the ninth step, and then forming the first oxide layer in the tenth step. A method of manufacturing a rocker-arm type polysilicon structure layer, characterized in that to implement a digital micromirror device by removing the layer and the second oxide layer by sacrificial etching.