KR20000044809A - Manufacturing method for two layered thin film micromirror array-actuated device - Google Patents

Abstract

PURPOSE: A manufacturing method for two layered TMA device is to provide the overall safe structure by preventing the over-etching by hardening the photoresist through the UV-curing process. CONSTITUTION: A device comprises a driving substrate(210), an insulation layer(211), a metal layer(214), a MOS transistor(212), a blocking layer(216), an upper part protection layer(217), an etching preventing layer(218), an actuator(230), a membrane(231), a lower electrode(232), and an electroplasive(233). A manufacturing method comprises a step of preparing a driving substrate in which the insulation layer, MOS transistor and the drain electrode are formed; a step of forming the first sacrificial layer in which the supporting part is formed; a step of forming the actuator in which the membrane, lower electrode, and the upper electrode are formed; a step of forming the second sacrificial layer having the photoresist on the upper part of the actuator; a step of depositing the mirror layer on the upper part of the second sacrificial layer; a step of forming a certain pattern on the photoresist; a step of hardening the upper surface of the photoresist; a step of partially etching the mirror layer; and a step of eliminating the first and second sacrificial layer.

Description

Manufacturing method of 2-layer thin film type optical path control device

In the present invention, in the process of coating a photoresist used as an etching mask for partially etching the mirror layer, the photoresist of the corner portion is formed thin according to the step of the upper portion of the mirror support portion, which is a partial etching process of the mirror layer Due to the excessive etching, the mirror layer of the Mosiri portion may be removed and damaged. Therefore, in order to remove this, the second layer which can prevent the excessive etching by curing the photoresist through UV-curing process before the partial etching process of the mirror layer. It relates to a method for manufacturing a thin film optical path control device having a structure.

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. CRT (Cathod Ray Tube) is a direct view type image display device, and a liquid crystal display device (hereinafter referred to as 'LCD'), a deformable mirror device (DMD), or TMA (Thin) is a projection type image display device. film Micromirror Array-actuated).

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 advantages described above, 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, devices such as DMD or TMA have been developed to solve the problems of the LCD as described above. Currently, TMA can achieve light efficiency of 10% or more, while DMD has light efficiency of about 5%. In addition, the TMA is not only affected by the polarity of the incident light beam, but also does not affect the polarity of the light beam.

Typically, each of the actuators formed inside the TMA causes deformation depending on the electric field generated by the applied image signal and bias voltage. When this actuator causes deformation, each mirror 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 the actuator, electrodistorted ceramics such as PMN (Pb (Mg, Nb) O ₃ ) may be used.

1A to 1G are cross-sectional views illustrating a manufacturing method of a conventional two-layer thin film type optical path control apparatus 100. As shown in FIG. 1A, the two-layer thin film type optical path control apparatus 100 is illustrated. ), The insulating substrate 111, the MOS transistor 112, the diffusion barrier layer 113, the metal layer 114, the lower protective layer 115, the blocking layer 116, the upper protective layer 117, the etch stop layer It starts with preparation of the drive board 110 in which 118 etc. are formed.

In the driving substrate 110, the MOS transistor 112 includes a gate oxide layer 112a, a gate electrode 112b, an interlayer insulating layer 112c, a source region 112d, a drain region 112e, and a field oxide layer 112f. ) Is formed. The diffusion barrier layer 113 prevents the silicon of the insulating substrate 111 from diffusing into the metal layer 114. The metal layer 114 may include drain pads 114a and source regions 112d formed to transmit electrical signals applied from the drain region 112e of the transistor 112 to respective actuators 130, which will be described later. It is formed by the part 114b which electrically connects. The lower protective layer 115 is formed to prevent the blocking layer 116 and the metal layer 114 from being electrically connected to each other. The blocking layer 116 is formed to prevent photocurrent caused by a photoelectric effect on the metal layer 114 formed below. The upper protective layer 117 is formed to protect the blocking layer 116 and the MOS transistor 112rk from being damaged during subsequent manufacturing processes. The etch stop layer 118 is formed to prevent the driving substrate 110 from being damaged during the subsequent etching process.

Subsequently, as illustrated in FIG. 1B, a first sacrificial layer 120 made of polycrystalline silicon (poly-Si) material is formed on the driving substrate 110 using low pressure vapor deposition (LPCVD). Here, in order to increase the flatness on the upper surface of the first sacrificial layer 120, it is planarized by using spin on glass (SOG) or chemical mechanical polishing (CMP). Subsequently, a portion formed on the drain pad 114a of the first sacrificial layer 130 is etched to form an actuator supporting portion 125 to be described later.

Subsequently, as illustrated in FIG. 1C, a membrane 131, platinum (Pt), or platinum / tantalum (Pt / Ta) made of nitride is formed on the first sacrificial layer 120 and the actuator support portion 125. A lower electrode 132 made of a material having excellent electrical conductivity, a strained layer 133 made of a piezoelectric material such as PZT or PLZT, an upper electrode 134 made of the same material as the lower electrode 132, and a lower electrode 132; The actuator 130, which is electrically connected to the drain pad 114a, is formed in this order.

Here, looking at the manufacturing process of the actuator 130, first, the membrane 131 made of nitride is formed to a thickness of 0.1-1.0㎛ using a low pressure chemical vapor deposition (LPCVD) method.

Next, a lower electrode 132 made of a metal having excellent electrical conductivity is formed on the membrane 131 to have a thickness of 0.1 to 1.0 μm using a sputtering method.

Next, a deformation layer 133 made of a piezoelectric material such as PZT or PLZT is formed on the lower electrode 132 to have a thickness of 0.1-1.0 μm using a sputtering or chemical vapor deposition (CVD) method. Subsequently, the strained layer 133 is phase shifted using a rapid heat treatment (RAT) method.

Subsequently, an upper electrode 134 made of a material having excellent electrical conductivity similar to that of the lower electrode 132 is formed on the deformation layer 133 by using a sputtering method.

Thereafter, the upper electrode 134, the strained layer 133, the lower electrode 132, and the membrane 131 are patterned in a desired shape by using a photoresist so as to be divided into respective actuators in a cell unit. The upper electrode 134, the strained layer 133, the lower electrode 132, the membrane 131, the etch stop layer 118, the upper protective layer 117 and the lower protective layer are formed from the portion where the drain pad 114a is formed. After the 115 is sequentially etched to form via holes (not shown), sputtering metals such as tungsten (W), platinum (Pt), aluminum (Al) or titanium (Ti) in the via holes is performed. The electric tube 135 is formed to electrically connect the lower electrode 132 and the drain pad 114a by using a method.

Subsequently, as illustrated in FIG. 1D, a second sacrificial layer 140 made of pocoresist or polycrystalline silicon (poly-Si) is formed on the actuator 130. Subsequently, the mirror supporting portion 145 is formed by partially removing the second sacrificial layer 140.

Next, as shown in FIG. 1E, in order to form the mirror layer 150 on the second sacrificial layer 140 and the mirror support part 145, a material having excellent reflection characteristics is deposited using a sputtering method. . Thereafter, the photoresist 152 is coated to form an etch mask for partially etching the mirror layer 150, and then the photoresist 152 is fixed to the photoresist 152 through a development process using a photosensitive mask. Form a pattern. Here, it can be seen that the thickness of the photoresist 152 formed at the edge of the upper portion of the mirror support 145 is formed thin.

Subsequently, as shown in FIG. 1F, the mirror layer 150 is etched along a predetermined pattern of the photoresist 152 so that the mirror layer 150 corresponds one-to-one to each actuator 130. . Thereafter, the photoresist 152 formed on top of the mirror layer 150 is subsequently removed.

Finally, as shown in FIG. 1G, the second sacrificial layer 140 and the first sacrificial layer 130 are removed to complete the TMA device.

However, in the manufacturing method of the two-layer thin film type optical path control apparatus 100 described above, in the process of coating the photoresist 152 used as an etching mask to partially etch the mirror layer 150 The photoresist of the corner portion is formed thin by the step of the upper portion of the support portion 145, which is removed by the excessive etching during the partial etching process of the mirror layer 150, the damage of the mirror layer 150 by removing the 2 There was a problem of structurally adverse effects on the thin film type optical path control device 100 of the layer structure.

The present invention has been made to solve the conventional problems as described above, the object of the present invention as described above, in the process of coating a photoresist used as an etching mask for partially etching the mirror layer, The photoresist at the edge part is formed thinly according to the step of the upper part of the support part. This is because there is a possibility that the mirror layer of the thin portion may be damaged due to the excessive etching during the partial etching process of the mirror layer. The present invention provides a method for manufacturing a thin film type optical path control device having a two-layer structure that prevents excessive etching by curing a photoresist through a UV-curing process before the partial etching process.

In order to achieve the object described above, the present invention provides an insulating substrate, a MOS transistor, a diffusion barrier layer, a metal layer consisting of a drain pad and a source connection portion, a lower protective layer, a blocking layer, an upper protective layer, an etch stop layer, and the like. Preparing a driving substrate; Forming a first sacrificial layer having an actuator support portion formed on the driving substrate; Forming an actuator having a membrane, a lower electrode, a deformation layer, an upper electrode, an electric tube, and the like formed on the first sacrificial layer and the actuator support part; Forming a second sacrificial layer including a mirror support portion on top of the actuator and the exposed first sacrificial layer; Depositing a mirror layer on top of the second sacrificial layer; Coating a photoresist on the mirror layer and forming a predetermined pattern on the photoresist through a development process using a photosensitive mask; Curing the upper surface of the photoresist through a UV-curing process; Partially etching the mirror layer along the pattern of the photoresist; Removing the second sacrificial layer and the first sacrificial layer.

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.

1A to 1G are cross-sectional views illustrating a method for manufacturing a conventional thin film optical path control apparatus having a two-layer structure;

2A to 2H are cross-sectional views illustrating a method for manufacturing a thin film optical path control apparatus having a two-layer structure according to the present invention.

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

210: driving substrate 211: insulating substrate

212: MOS transistor 213: diffusion barrier layer 214: metal layer

215: lower protective layer 216: barrier layer 217: upper protective layer

218: etch stop layer 220: first sacrificial layer

225: actuator support portion 230: actuator 231: membrane

232: lower electrode 233: strained layer 234: upper electrode

235: total length 240: second sacrificial layer 245: mirror support portion

250: mirror 252: photoresist

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

2A to 2H are cross-sectional views illustrating a method of manufacturing a two-layer thin film optical path control apparatus 200 in accordance with the present invention. As shown in FIG. 2A, the two-layer thin film optical path control apparatus is illustrated. The insulating substrate 211, the MOS transistor 212, the diffusion barrier layer 213, the metal layer 214, the lower passivation layer 215, the blocking layer 216, the upper passivation layer 217, and the etching may be manufactured. It begins with preparation of the drive substrate 210 in which the prevention layer 218 etc. are formed.

In the driving substrate 210, the MOS transistor 212 includes a gate oxide layer 212a, a gate electrode 212b, an interlayer insulating layer 212c, a source region 212d, a drain region 212e, and a field oxide layer 212f. ) Is formed. The diffusion barrier layer 213 prevents the silicon of the insulating substrate 211 from diffusing into the metal layer 214. The metal layer 214 is a drain pad 214a and a source region 212d which are formed to transfer an electrical signal applied from the drain region 212e of the transistor 212 to each actuator 230 to be formed later. ) Is formed into a portion 214b that electrically connects them. The lower protective layer 215 is formed to prevent the blocking layer 216 and the metal layer 214 from being electrically connected to each other. The blocking layer 216 is formed to prevent photocurrent caused by a photoelectric effect on the metal layer 214 formed under the blocking layer 216. The upper protective layer 217 is formed to protect the blocking layer 216 and the MOS transistor 212 from being damaged during subsequent manufacturing processes. The etch stop layer 218 is formed to prevent the driving substrate 210 from being damaged during the subsequent etching process.

Subsequently, as illustrated in FIG. 2B, a first sacrificial layer 220 made of poly-silicon (poly-Si) is formed on the driving substrate 210 using low pressure vapor deposition (LPCVD). Here, in order to increase the flatness on the upper surface of the first sacrificial layer 220, it is planarized by using spin on glass (SOG) or chemical mechanical polishing (CMP). Subsequently, a portion 225 is formed on the drain pad 214a of the first sacrificial layer 220 to etch the portion to form a portion 225 on which the supporting portion of the actuator 230 is to be formed.

Subsequently, as illustrated in FIG. 2C, a material having excellent electrical conductivity such as a membrane 231 made of nitride, platinum (Pt), or platinum / tantalum (Pt / Ta) is formed on the first sacrificial layer 220. The lower electrode 232, the strained layer 233 made of piezoelectric material such as PZT or PLZT, the upper electrode 234 made of the same material as the lower electrode 232, the lower electrode 232 and the drain pad 214a are electrically connected. The actuator 230 is formed to connect the front tube 235 and the like.

Here, looking at the manufacturing process of the actuator 230, first, the membrane 231 made of nitride is formed to a thickness of 0.1-1.0㎛ using a low pressure chemical vapor deposition (LPCVD) method.

Next, a lower electrode 232 made of a metal having excellent electrical conductivity is formed on the membrane 231 to a thickness of 0.1 to 1.0 μm using a sputtering method.

Next, a strain layer 233 made of a piezoelectric material such as PZT or PLZT is formed on the lower electrode 232 to a thickness of 0.1 μm to 1.0 μm using a sputtering or chemical vapor deposition (CVD) method. Subsequently, the strained layer 233 is phase shifted using a rapid heat treatment (RAT) method.

Subsequently, an upper electrode 234 made of a material having the same excellent electrical conductivity as that of the lower electrode 232 is formed on the strained layer 233 using a sputtering method.

Thereafter, the upper electrode 234, the strained layer 233, the lower electrode 232, and the membrane 231 are divided into respective actuators 230 in a cell unit. Pattern.

Then, the upper electrode 234, the strained layer 233, the lower electrode 232, the membrane 231, the etch stop layer 218, the upper protective layer 217, and the lower protective part from the portion where the drain pad 214a is formed. The vias 215 are sequentially etched to form via holes (not shown), and then metals such as tungsten (W), platinum (Pt), aluminum (Al), or titanium (Ti) are formed in the via holes. The front tube 235 is formed to connect the lower electrode 232 and the drain pad 214a by using a sputtering method. The lower tube 232 is electrically connected to the MOS transistor 220 of the driving substrate 210 by the lower electrode 232 of the actuator 230 through the drain pad 214a. To work.

Subsequently, as shown in FIG. 2D, the second sacrificial layer 240 including the mirror support part 245 is formed on the actuator 230 and the exposed first sacrificial layer 220. Herein, a process of forming the second sacrificial layer 240 including the mirror support part 245 will be described. First, after forming the second sacrificial layer 240 made of photoresist or poly-silicon, the second sacrificial layer 240 may be formed. The mirror support portion 245 is formed by removing a portion of the second sacrificial layer 240.

Then, as illustrated in FIG. 2E, a material having excellent reflection characteristics such as aluminum (Al) or platinum (Pt) on the second sacrificial layer 240 and the mirror support portion 245 may be formed using a sputtering method. Deposition is performed to form the mirror layer 250. Thereafter, in order to form a mask for partial etching of the mirror layer 250, the photoresist 252 is coated on the mirror layer 250, and then the photoresist is developed through a development process using a photosensitive mask. A predetermined pattern is formed at 252. Here, it can be seen that the thickness of the photoresist 252 formed at the edge of the upper portion of the mirror support portion 245 is formed thin.

Subsequently, as shown in FIG. 2F, the thickness formed at the upper edge of the mirror support part 245 is thin so that the mirror layer 250 may not be over-etched during the process. The photoresist 252 is cured through a UV-curing process of heating at a temperature of about 150 ° C.) and irradiating ultraviolet rays. The ultraviolet rays irradiated at this time are different from the ultraviolet rays and the wavelength region during the development process, and thus can harden the surface without breaking the cross-link of the photoresist.

Thereafter, as shown in FIG. 2G, the mirror layer 250 is partially etched along the pattern of the photoresist 252 so that the mirror layer 250 has a one-to-one correspondence with the lower actuator 230. To be In addition, the photoresist 252 formed on the mirror layer 250 is completely removed in a subsequent process.

Finally, as shown in FIG. 2H, the second sacrificial layer 240 and the first sacrificial layer 230 are removed to complete the TMA device.

As described above, the method of manufacturing a two-layer thin film type optical path control apparatus according to the present invention is a step of coating a photoresist used as an etching mask for partially etching the mirror layer, wherein Therefore, the photoresist of the edge portion is thinly formed, and this may be damaged due to the excessive removal of the mirror layer of the rice seedling portion due to the excessive etching during the partial etching process of the mirror layer. By curing the photoresist through the -curing process, it is possible to prevent over-etching, thereby achieving overall structural stabilization.

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. It will be appreciated.

Claims (2)

Preparing a driving substrate on which an insulating substrate, a MOS transistor, a diffusion barrier layer, a metal layer including a drain pad and a source connection part, a lower protective layer, a blocking layer, an upper protective layer, an etch stop layer, and the like are formed; Forming a first sacrificial layer having an actuator support portion formed on the driving substrate; Forming an actuator having a membrane, a lower electrode, a deformation layer, an upper electrode, an electric tube, and the like formed on the first sacrificial layer and the actuator support part; Forming a second sacrificial layer including a mirror support portion on top of the actuator and the exposed first sacrificial layer; Depositing a mirror layer on top of the second sacrificial layer; Coating a photoresist on the mirror layer and forming a predetermined pattern on the photoresist through a development process using a photosensitive mask; Curing the upper surface of the photoresist through a UV-curing process; Partially etching the mirror layer along the pattern of the photoresist; The method of claim 2, wherein the second sacrificial layer and the first sacrificial layer are removed. The method of claim 1, wherein the UV-curing process is performed while heating to a temperature of about 150 ° C. on a hot plate.