KR100220683B1 - The fabrication method for thin film actuated mirror array and sacrificial layer etcher - Google Patents

Abstract

The present invention relates to a sacrificial film etching apparatus for an optical path adjusting apparatus capable of uniformly advancing a damage of a photoresist protective film, which is unavoidably caused when a sacrificial film is removed, thereby improving the production yield of the optical path adjusting apparatus. An inlet pipe 33 for connecting the reaction chamber 32 and the etching chamber 35, a valve for introducing the carrier gas, A vacuum pump 41 for forming a vacuum in the etching apparatus, and a rotation pedestal 39 provided inside the etch pamba 35. The vacuum pump 40 includes an exhaust pipe 34 for exhausting the etching residue, And a unifier (43) installed on the rotation support (39).

Therefore, according to the present invention, it is possible to prevent the inflow of moisture in the air during the sacrificial layer etch process, thereby suppressing bubbling or cracking of the photoresist protective film, and also to prevent the damage of the photoresist protective film Thereby making it possible to improve the production yield of the optical path adjusting device.

Description

METHOD FOR MANUFACTURING OPTICAL ROUTE CONTROL DEVICE AND SCATTERING MEMBER

The present invention relates to a fabrication method of an optical path adjusting device used in a projection type image display apparatus, and more particularly, to a fabrication method of an optical path adjusting apparatus by uniformly advancing a damage of a photoresist protective film which is inevitable in removing a sacrificial film, The present invention relates to an apparatus for etching a sacrificial film of an optical path adjusting apparatus capable of making an optical path adjustment apparatus.

The image display apparatus is divided into a direct view type image display apparatus and a projection type image display apparatus according to a display method. The projection type image display apparatus has a feature of displaying high image quality even on a large screen. In such a projection type image display apparatus, the light flux from the light source is uniformly divided into M N active mirrors in which each mirror is coupled to a respective actuator and the actuator is made of an electrostrictive or piezoelectric material that causes deformation by the applied electric field. When such an actuator is M N-type matrix to form an optical path adjusting device.

On the other hand, the luminous flux reflected from each mirror is incident on the hole of the optical baffle. When an electric signal is applied to each actuator, the overall position of each mirror is changed, and the optical path of the luminous flux reflected from each mirror is changed. As the refraction of each reflected light flux changes, the amount of light passing through the aperture of the optical device is changed to control the intensity of the light. The light beam passing through the hole is projected onto the projection surface through a suitable optical device such as a projection lens and displays an image thereon.

1 (a) to 1 (d) show a manufacturing process of a conventional optical path adjusting apparatus of an image display apparatus having such a principle.

Referring to FIG. 1 (a), a driving substrate 11 (not shown) having a pad 13 formed of a metal such as aluminum (Al) electrically connected to the transistor and a transistor (not shown) A sacrificial layer 15 for forming an air gap is formed to a thickness of about 0.1 to 2 탆. The sacrifice layer 15 at the portion where the pad 13 is formed is removed by a normal photolithography method and a dry and wet etching method to expose the pad 13 and the peripheral drive substrate 11.

Referring to FIG. 1 (b), a membrane 17 is formed to a thickness of about 0.1 to 2 μm on the driving substrate 11 and the sacrifice layer 15. A groove is formed in a predetermined portion of the membrane 17 so as to expose the pad 13 and then a conductive metal is filled in the groove to form a plug 19 electrically connected to the pads 13 do. Subsequently, a lower electrode 21 having a thickness of about 500 Å to 2000 Å is formed on the membrane 17 so as to be electrically connected to the plug 19. Therefore, the pad 13 and the lower electrode 21 are electrically connected to each other by the plug 19.

Referring to FIG. 1 (c), a deformed portion 23 and an upper electrode 25 are formed on the surface of the lower electrode 21. The deformed portion 23 is formed by applying piezoelectric ceramics or electrostrictive ceramics to a thickness of about 0.1 to 2 μm and the upper electrode 25 is formed by depositing a metal having good reflection characteristics and electrical characteristics. Subsequently, the upper electrode 25, the deformed portion 23, the lower electrode 21, and the membranes 17 are etched so that the driving substrate 11 is exposed to separate the actuators. The upper electrode 25, the deformed portion 23, the lower electrode 21 and the membranes 17 are etched by reactive ion etching (RIE) using the respective etching masks. Then, a photoresist protective film 27 is formed on the side surfaces of the upper electrode 25 and the actuator by separating them.

Referring to FIG. 1 (d), a nitrogen gas containing an etching solution such as a hydrofluoric acid solution (HF) is sprayed on the upper surface of the optical path adjusting device 38 using an etching apparatus to remove the sacrificial film 15, Thereby forming a gap. At this time, the protective film 27 of the photoresist protective film 27 prevents the side surfaces of the membrane 17 and the deformed portion 23 from being etched to peel off the respective layers. Then, the photoresist protective film 27 is removed to complete the manufacture of the optical path adjusting device.

Particularly, the sacrificial film etching process for removing the sacrificial layer 15 is performed in a separate etching apparatus. The etching apparatus includes a reaction chamber for storing hydrofluoric acid in a bubble state, an etching chamber having a branch and a fixing plate, An inlet pipe connecting the reaction chamber and the etching chamber for introducing the hydrofluoric acid in the bubbled state of the etching chamber into the etching chamber, a valve for introducing the carrier gas, an exhaust pipe for discharging the etching residue, And a vacuum pump.

In the etching process using such an etching apparatus, when nitrogen gas is supplied through the bubbling tube in the state where the etching solution such as a hydrofluoric acid solution is stored in the reaction chamber, bubbles are generated in the hydrofluoric acid solution, And floats inside the reaction chamber.

Meanwhile, by operating a vacuum pump installed at one end of the exhaust pipe, a vacuum is formed inside the etching chamber and the inlet pipe, so that the nitrogen gas containing the hydrofluoric acid solution in the reaction chamber is injected into the etching chamber through the inlet pipe.

Also, the concentration of the etching solution such as hydrofluoric acid is adjusted by adjusting the amount of the nitrogen gas supplied through the valve formed at one end of the inflow channel.

On the other hand, nitrogen gas containing hydrofluoric acid is injected through the injector of the etching chamber, and is sprayed on the upper surface of the optical path adjusting device mounted on the upper surface of the rotary pedestal, thereby etching the sacrificial film.

However, the tantalum oxide remains on the upper surface of the actuator due to the progress of the etching process in the manufacturing process of the optical path adjusting device, so that a small amount of tantalum oxide is contained in the photoresist layer when the photoresist protective film is formed. The thermal expansion coefficient of the resist is different from that of tantalum oxide, so that contraction of the tantalum oxide occurs to form bubbles in the photoresist protective film, or cracks are generated in the photoresist protective film due to the shrink stress of the photoresist protective film There was a problem.

In addition, when the sacrificial layer is removed by the etching process, the nitrogen gas injected to form hydrofluoric acid in the form of water or foam due to the reaction between the SiO ₂ component and the hydrofluoric acid of the PSG of the sacrificial film is introduced together with moisture in the air The concentration of nitrogen gas containing hydrofluoric acid can not be appropriately controlled due to the water content, so that the fluorine group (F < ^- >) remains in the etching residue, thereby invading the photoresist protective film.

Particularly, penetration of hydrofluoric acid through such bubbles or cracks causes damage to the active device or leakage current to cause a problem of deteriorating the characteristics of the optical path control device.

In order to solve this problem, conventionally, in order to prevent damage of the photoresist protective film, it is necessary to reduce the amount of nitrogen gas injected to form hydrofluoric acid in the form of bubbles, A method of increasing the etching rate was proposed to prevent damage to the photoresist protective film, but there was a disadvantage that the time required for etching was prolonged.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method and apparatus for cleaning a photoresist protective film by rotating an optical path adjusting device including an actuator and a driving substrate during the etching process so as to uniformly damage the photoresist protective film, The nitrogen gas containing hydrofluoric acid is locally penetrated to prevent the actuator from being exposed and damaged.

According to an aspect of the present invention, there is provided a plasma etching apparatus including a reaction chamber provided with a bubble generating tube, an etching chamber provided with an injector, an inlet pipe connecting the reaction chamber and the etching chamber, a valve for introducing the carrier gas, A vacuum pump for forming a vacuum inside the etching apparatus, and a rotary pedestal provided inside the etching chamber.

FIG. 1 (a) through FIG. 1 (d) also show a manufacturing process of a conventional optical path adjusting device.

FIG. 2 is a device diagram for a wet etching apparatus of an optical path adjusting apparatus according to the present invention; FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

31: bubble generating tube 32: reaction chamber

33: inlet pipe 34: valve

35: etch chamber 36: injector

37: Nozzle 38: Optical path adjustment device

39: rotating pedestal 40: exhaust pipe

41: vacuum pump 42, 42 ': filtration means

43: Uniform

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a sacrificial film etching apparatus for an optical path adjusting apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a method of manufacturing a semiconductor device, comprising: forming a sacrificial layer on a driving substrate having a transistor embedded in a matrix and having a pad electrically connected to each transistor on a surface; Forming a protective film on a surface of the upper electrode and a side surface of the actuator, removing the sacrificial film, removing the sacrificial film, removing the sacrificial film, In the method of manufacturing an optical path adjusting device comprising an etching process, the optical path adjusting device is rotated while having a predetermined number of rotations in the sacrificial layer etching process.

FIG. 2 is a configuration diagram of a wet etching apparatus of an optical path adjusting apparatus according to an embodiment of the present invention.

The sacrificial layer etching apparatus for an optical path adjusting apparatus according to the present invention includes a reaction chamber 32 provided with a bubble generating tube 31 for injecting nitrogen gas so as to store hydrofluoric acid in a bubble state, An etching chamber 35 provided with a rotation support 39 for rotating the reaction chamber 32 and an inlet pipe 33 connecting the reaction chamber 32 and the etching chamber 35, A vacuum pump 41 for forming a vacuum in the interior of the etching apparatus and an exhaust pipe 40 for exhausting the etching residue are provided at one end of the bubble generating pipe 31 and the inflow pipe 33 And filtration means 42 and 42 '.

The reaction chamber 32 of the wet etching apparatus of the optical path adjusting device 38 having the above-described structure is a container for storing a hydrofluoric acid solution. The reaction chamber 32 is made of an acid resistant material which does not corrode etching solution such as hydrofluoric acid. A bubble generating tube 31 capable of injecting nitrogen gas into the bubble generating tube 31 is installed at one end of the reaction chamber 32 and a filtering means 42 is installed at one end of the bubble generating tube 31 And the lower portion is installed so as to be immersed in an etching solution such as hydrofluoric acid.

A carrier gas composed of a nitrogen gas is introduced into one end of the inflow conduit 33 so that a nitrogen gas containing an etching solution such as hydrofluoric acid is injected in a direction toward the side of the etching chamber 35 toward the etching chamber 35 side A valve 34 is provided so that it can be blown in the direction of the air, and a filtration means 42 'is provided.

The etch chamber 35 is made of an acid-resistant material and includes an injector 36 having a plurality of fine nozzles 37 disposed therein in the horizontal direction and a rotary base 39 for rotating the optical path adjuster 38 Is mounted on the upper portion of the injector 36. [

On the other hand, a unifier (43) is provided between the rotating pedestal (39) and the injector to solve the problem that the etch rate of the outer portion of the driving substrate rapidly appears due to the rotation of the optical path adjusting device.

The unifier 43 is a rotary member for improving the etching uniformity in the etching process. A plurality of vanes are radially installed to be rotated by a motor. The vane 43 is formed to have a wider width from the center toward the outer side. The amount of the etchant sprayed is reduced.

The exhaust pipe 40 is connected to the lower end of the etching chamber 35 and is connected to one end of the exhaust pipe 40 through a vacuum pump 40 for forming a vacuum in the interior of the etching device 40. [ (41).

The sacrificial layer etching apparatus of the optical path adjusting apparatus 38 thus constructed is an apparatus for forming an air gap by removing a sacrificial layer of an actuator. In order to prevent the side surfaces of the membrane and the deformed portion from being etched, And then the photoresist protective film is formed on the actuators including the surface of the electrode, and then proceed.

First, an etching solution such as a hydrofluoric acid solution is stored in the reaction chamber 32. When nitrogen gas is supplied through the bubble generating tube 31, bubbles are generated in the hydrofluoric acid solution, and the nitrogen gas containing hydrofluoric acid And floats inside the reaction chamber 32.

The vacuum pump 41 installed at one end of the exhaust pipe 40 forms a vacuum in the etching chamber 35 and the inlet pipe 33 while moving the reaction chamber 32 in the direction of the etching chamber 35 The nitrogen gas containing the hydrofluoric acid solution in the reaction chamber 32 existing in a bubble state by the nitrogen gas is injected into the etching chamber 35 through the inflow conduit 33.

The nitrogen gas supplied through the valve 34 formed at one end of the inlet pipe 33 is a nitrogen gas carrier gas containing hydrofluoric acid and the amount thereof is controlled to adjust the concentration of nitrogen gas containing hydrofluoric acid.

The nitrogen gas containing the hydrofluoric acid is injected into the etching chamber 35 and diffuses due to the expansion of the space. The nitrogen gas containing the hydrofluoric acid is diffused by the rotation support plate 39 through the injector 36 having the plurality of nozzles 37 And is sprayed onto the upper surface of the optical path adjusting device 38 rotating at a rotating speed.

At this time, since the optical path adjusting device 38 is rotated by the rotation supporting plate 39, it is possible to obtain the effect that the nitrogen gas containing hydrofluoric acid is dispersed without being concentrated on a part of the optical path adjusting device 38.

On the other hand, the nitrogen gas containing hydrofluoric acid is injected into the central portion of the optical path adjusting device 38, and the etching speed of the outer portion is faster than the center due to the rotation of the optical path adjusting device 38. The wings are formed so as to have a wider width so as to block the amount of etchant sprayed outwardly from the center so that the etch rate of the outside of the drive substrate 100 does not proceed too fast as compared with the etch rate of the center.

On the other hand, the filtration means 42 and 42 'provided in the bubble generating tube 31 and the inflow conduit 33 filter the moisture or dust in the air when the nitrogen gas flows in the air, So that the generation of the fluorine group (F < ^- >) in the residue is inhibited, thereby preventing local damage of the photoresist layer.

As described above, according to the present invention, it is possible to prevent moisture from entering the atmosphere during the sacrificial layer etching process, thereby suppressing bubbling or cracking of the photoresist protective film, and also to prevent the damage of the photoresist protective film, Thereby making it possible to improve the production yield of the optical path adjusting device.

Claims (1)

A reaction chamber 32 provided with a bubble generating tube 31, an etching chamber 35 provided with an injector 36, an inflow conduit 33 connecting the reaction chamber 32 and the etching chamber 35, A vacuum pump 41 for forming a vacuum inside the etching apparatus, and a valve 34 for introducing the carrier gas into the etching chamber 35. The valve 34 is provided for introducing the carrier gas, The sacrificial film etching apparatus of an optical path adjusting apparatus according to any one of claims 1 to 4, further comprising a unit holder (43) mounted on the rotating support (39).