KR20090107702A - Thin-film Deposition Method and Device - Google Patents

Abstract

PURPOSE: A thin-film deposition method and device is provided to improve productivity and reduce investment cost by reducing the number of the deposition chamber. CONSTITUTION: The thin-film deposition method and device comprises as follows. The amorphous ITO film is formed by adding H2 to the top of the substrate. The metal layer is accumulated and is formed at the top of the substrate in which the amorphous ITO film is formed. The thin-film deposition device includes the loader(215) settled in the upper part of the carrier, the heating chamber(220) which preheating the substrate, and the deposition chamber(230) which consecutively forms the amorphous ITO film and metal layer on the substrate, the cooling chamber(240) for cooling the substrate which the crystalline ITO film and metal layer and the unloader(245) for transferring the substrate.

Description

Thin Film Deposition Method and Equipment

The present invention relates to a thin film deposition method and equipment, and more particularly to a thin film deposition method and equipment that can reduce the initial investment cost and clean room area.

In general, a liquid crystal display device includes an array substrate and a color filter substrate, and a liquid crystal layer interposed between the array and the color filter substrate. The driving principle of the liquid crystal display device uses optical anisotropy and polarization property of the liquid crystal. Since the liquid crystal is thin and long in structure, the liquid crystal has directivity in the arrangement of molecules and artificially controls the direction of the molecular arrangement by applying an electric field to the liquid crystal. can do.

Accordingly, when the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular arrangement direction of the liquid crystal due to optical anisotropy to express image information.

Currently, active matrix LCDs (AM-LCDs) in which thin film transistors and pixel electrodes connected to the thin film transistors are arranged in a matrix manner are attracting the most attention because of their excellent resolution and video performance.

Hereinafter, a liquid crystal display according to the related art will be described with reference to the accompanying drawings.

1 is a schematic cross-sectional view of a liquid crystal display according to the related art.

As shown in the drawing, the conventional liquid crystal display device 90 includes a liquid crystal panel 50, a backlight unit 80 disposed on the rear surface of the liquid crystal panel 50, and a driving circuit unit (not shown). The liquid crystal panel 50 is divided into a display area AA and a non-display area NAA, and is bonded to each other, and is bonded to each other, and the color filter substrate 5 and the array substrate. And a liquid crystal layer 15 having a constant cell gap G interposed therebetween.

The lower surface of the transparent substrate 1 of the color filter substrate 5 is disposed on the black matrix 12 for blocking light incident to the non-display area NAA, and is disposed on the lower surface of the black matrix 12. The color filter layer 14 including the red (R), green (G), and blue (B) sub color filters 14a, 14b, and 14c sequentially patterned to realize the color filter layer 14 and the lower surface of the color filter layer 14 The common electrode 16 made of a transparent conductive metal on the substrate and the upper alignment layer 18 for uniform alignment of the liquid crystal are sequentially placed.

Although not shown in the drawings, an overcoat layer (not shown) may be further configured for the purpose of planarization between the color filter layer 14 and the common electrode 16.

On the other hand, the upper surface of the transparent substrate 2 of the array substrate 10 covers a gate wiring (not shown) and a gate electrode 25 configured in one direction, and an upper front surface of the gate wiring and the gate electrode 25. A gate insulating layer 45, a semiconductor layer 42 disposed on the gate insulating layer 45, and a portion of the gate electrode 25 overlapping the gate insulating layer 45, and vertically intersecting with the gate wiring on the semiconductor layer 42. A data line 30 defining a pixel region P, a source electrode 32 extending from the data line 30, a drain electrode 34 spaced apart from the source electrode 32, and the data line Contact with the drain electrode 34 through the passivation layer 55 covering the upper surface of the source and drain electrodes 32 and 34 and the drain contact hole CH1 exposing a part of the drain electrode 34. The pixel electrode 70 and the lower alignment layer 19 covering the upper entire surface of the pixel electrode 70. Located.

The semiconductor layer 42 includes an active layer 40 made of pure amorphous silicon (a-Si: H) and an ohmic contact layer 41 made of an amorphous silicon layer (n + a-Si: H) containing impurities. Include. The ohmic contact layer 41 exposed between the source and drain electrodes 32 and 34 spaced apart from each other is formed on both sides, and the lower active layer 40 is overetched to use this portion as a channel ch. do.

In this case, the gate electrode 25, the gate insulating layer 45, the semiconductor layer 42, and the source and drain electrodes 32 and 34 are referred to as a thin film transistor T.

The above-described process of manufacturing the array substrate 10 for a liquid crystal display device is performed by stacking thin films through a series of repetitive operations of depositing a metal film, an amorphous silicon film, a crystalline ITO film, a protective film, and the like on the transparent insulating substrate 2. In addition, a desired pattern is formed through a photolithography process in which photoresist is applied, exposed, developed, and patterned.

Through this pattern process, the metal film is formed of the gate wiring or data wiring 30, the amorphous silicon film is formed of the semiconductor layer 42, and the crystalline ITO film is formed of the pixel electrode 70.

Currently, the array substrate 10 for a liquid crystal display device is generally manufactured through four to six photolithography processes. In the photolithography process that proceeds with this series of processes, the number of times the mask is used is directly related to the initial investment cost and the production yield.

In recent years, research has been actively conducted to fabricate the array substrate 10 for a liquid crystal display device in three photolithography processes. In this three mask process step, the above-described crystalline ITO film and a metal film are sequentially stacked and formed. You will proceed to the steps.

This will be described in detail with reference to the accompanying drawings.

FIG. 2 is a process flowchart schematically illustrating an inline manufacturing process, and FIG. 3 is a cross-sectional view schematically illustrating a state in which a crystalline ITO film and a metal film are formed on a substrate in a non-continuous manner. The process of laminating a metal film is shown mainly.

As shown in FIG. 2 and FIG. 3, the thin film deposition apparatus 100, which proceeds in an inline manner according to the related art, includes a loader 115 into which a substrate 110 mounted on an upper surface of a carrier 105 is inserted, and the loader The first deposition chamber forming the crystalline ITO film 150 on the heating chamber 120 to preheat the substrate 110 passed through the 115 and the upper surface of the substrate 110 exiting the heating chamber 120 ( 130, a second deposition chamber 135 forming a metal film 160 on an upper surface of the substrate 110 on which the crystalline ITO film 150 is formed through the first deposition chamber 130, and the crystalline ITO film. A cooling chamber 140 for cooling the substrate 110 on which the 150 and the metal film 160 are formed, and an unloader 145 for transporting the substrate 110 passing through the cooling chamber 140. .

In this case, sputtering deposition equipment is mounted in the first and second deposition chambers 130 and 135, respectively.

Although not shown in the drawings, an etching chamber (not shown) for patterning a thin film on the substrate 110 passing through the first and second deposition chambers 130 and 134 and a pattern formed on the substrate 110 may be formed. After that, a strip chamber (not shown) or the like for removing the remaining photoresist is further mounted. The first and second deposition chambers 130 and 135, including an etching chamber and a strip chamber, are referred to as a process chamber (not shown). A plurality of load lock chambers 125 are further mounted in the spaces between the plurality of chambers except the loader 115 and the unloader 145 to maintain a vacuum atmosphere.

In this case, as shown in FIG. 3, a crystalline ITO film 150 is formed on the upper surface of the substrate 110 passing through the first deposition chamber 130, and the crystalline ITO passing through the second deposition chamber 135. The metal film 160 is further formed on the upper surface of the substrate 110 including the film 150. That is, the crystalline ITO film 150 and the metal film 160 are formed discontinuously in different deposition chambers.

In the thin film deposition apparatus 100 in the aforementioned inline method, the crystalline ITO film 150 and the metal film 160 are discontinuously formed, which is a problem such as an increase in the initial investment cost of the equipment and an increase in the area of the clean room. It contains.

In addition, the crystalline ITO film 150 has a low etching rate, which not only acts as a factor in delaying the process time but also causes side effects due to the use of a mixture of nitric acid and hydrochloric acid as an etchant used during the etching process.

The mixture of nitric acid and hydrochloric acid is a strong acid having strong acidity. In the process of patterning the crystalline ITO film, when a crack occurs in the insulating film, a mixture of nitric acid and hydrochloric acid flows into the minute gap and enters the lower portion of the insulating film. It may cause a problem of disconnecting the gate wiring or the data wiring located in the.

The present invention has been made to solve the above-mentioned problems, and by using amorphous ITO which has better etching rate than crystalline ITO and does not damage the underlying metal, the continuous film forming process between the amorphous ITO film and the metal film is not performed. An object of the present invention is to propose a method and equipment for thin film deposition that can proceed.

The thin film deposition method according to the present invention for achieving the above object comprises the steps of forming an amorphous ITO film by adding H ₂ on the substrate; And laminating a metal film on the substrate on which the amorphous ITO film is formed.

In this case, the amorphous ITO film and the metal film are patterned using different etchant, and the etchant used for patterning the amorphous ITO film is oxalic acid.

After patterning the amorphous ITO film, and further comprising the step of crystallizing at a temperature of 240 to 350 ℃.

Thin film deposition apparatus according to the present invention for achieving the above object and the loader is placed on the substrate seated on the carrier upper surface; A heating chamber for preheating the substrate passing through the loader; A deposition chamber for continuously forming an amorphous ITO film and a metal film on the upper surface of the substrate exiting the heating chamber; A cooling chamber for cooling the substrate on which the crystalline ITO film and the metal film are formed; It characterized in that it comprises an unloader for transferring the substrate passed through the cooling chamber.

At this time, H ₂ is added during the deposition process of the amorphous ITO film.

In the present invention, first, the number of deposition chambers can be reduced by forming the amorphous ITO film and the metal film as a continuous film instead of a continuous film, thereby improving productivity and reducing initial investment costs.

Second, the crystallization temperature of the amorphous ITO can be increased by adding H ₂ in the amorphous ITO deposition process.

Third, the use of oxalic acid as an etchant in the patterning process of amorphous ITO can prevent the lower metal from being damaged in advance, and the process time can be shortened because the etching rate is higher than that of crystalline ITO.

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The present invention is characterized by providing a thin film deposition method and equipment that can form an amorphous ITO film and a metal film in one deposition chamber by adding H ₂ in the deposition process of the amorphous ITO film.

4 is a process flowchart schematically illustrating an inline manufacturing process according to the present invention, and FIG. 5 is a cross-sectional view schematically illustrating a state in which an amorphous ITO film and a metal film are continuously formed on a substrate.

As shown in FIG. 4 and FIG. 5, the thin film deposition apparatus 200 which proceeds in an inline manner according to the present invention includes a loader 215 into which a substrate 210 seated on an upper surface of a carrier 205 is inserted. An amorphous ITO film 250 and a metal film 260 are formed on a heating chamber 220 for preheating the substrate 210 passing through the loader 215, and an upper surface of the substrate 210 exiting the heating chamber 220. A substrate that passes through the deposition chamber 230, the cooling chamber 240 for cooling the substrate 210 on which the amorphous ITO film 250 and the metal film 260 are formed, and the cooling chamber 240. And an unloader 245 for conveying 210.

In this case, the heating chamber 220 may be divided into first and second heating chambers (not shown) in which processes are performed at different temperatures.

Although not shown in the drawings, an etching chamber (not shown) for patterning a thin film on the substrate 210 passing through the deposition chamber 230 is provided in a space between the deposition chamber 230 and the cooling chamber 240. A strip chamber (not shown) or the like for removing the remaining photoresist after forming a pattern on the 210 is further mounted. The deposition chamber 230 is referred to as a process chamber including an etching chamber, a strip chamber, and the like. A plurality of load lock chambers 225 are further mounted in the spaces between the plurality of chambers except the loader 215 and the unloader 245 to maintain a vacuum atmosphere.

The deposition chamber 230 is characterized in that a hybrid type sputtering deposition equipment capable of continuously forming the amorphous ITO film 250 and the metal film 260 is used. Generally, argon (Ar) is used as a carrier gas and O ₂ is used as a reaction gas for amorphous ITO deposition. Alternatively, the deposition process may be performed using only argon gas as the carrier gas and the reaction gas.

The crystallization temperature of the amorphous ITO is generated at approximately 120 ° C., which proceeds at a temperature lower than the hard baking process temperature (approximately 140 ° C.) for applying and curing the photoresist, so that the deposition process of amorphous ITO at room temperature Even if this proceeds, there is a problem that the crystallization of the amorphous ITO during the hard baking process of the photoresist proceeds.

Therefore, in the present invention, after forming the amorphous ITO film 250 by using a sputtering deposition equipment of the hybrid method, it is characterized in that to add H ₂ O or H ₂ to maintain the amorphous state even at 140 ℃ or more. At this time, it is preferable to use H ₂ rather than H ₂ O.

The H of H ₂ O and H ₂ acts as a factor that interferes with the crystal growth of amorphous ITO to delay the progress of crystallization. Therefore, the amorphous ITO does not crystallize even at a high temperature of 140 ° C or higher.

However, since H ₂ O acts as a factor that hinders the degree of vacuum inside the deposition apparatus in which the process is performed in a vacuum state, the H ₂ O may act as a factor of increasing the specific resistance value when the metal film 260 is formed.

That is, H ₂ O transports the upper surface of the substrate 210 or the substrate 210 when the amorphous ITO film 250 is formed and the metal film 260 is continuously formed on the upper surface of the amorphous ITO film 250. And each chamber is moved with O or OH attached to the upper or lower surface of the supporting carrier 205.

The O is deposited on the upper surface of the amorphous ITO film 250, and the deposition process of the metal film 260 as well as on the boundary surface between the amorphous ITO film 250 and the metal film 260. Formation of the metal oxide by O may act as a factor of increasing the specific resistance value of the entire portion of the metal film 260 and may cause a problem of lowering the electrical conductivity of the metal film 260.

On the contrary, since H ₂ does not have O, such a problem does not occur. When H ₂ is added during deposition of amorphous ITO, crystallization of amorphous ITO can be prevented even at 140 ° C. or higher, and amorphous without deteriorating electrical conductivity by O. There is an advantage in that the ITO film 250 and the metal film 260 can be formed continuously.

The film thickness and specific resistance of the amorphous ITO change depending on whether H ₂ is injected and the deposition time, and the resistivity decreases as the film thickness increases, that is, as the deposition time increases.

The high resistivity means that the conductor is not of good quality. The specific resistance is usually expressed by ρ, which is equal to the resistance value R of the sample multiplied by the cross-sectional area A and divided by the length l. Ρ = RA / l. The unit of resistance is Ω.

At this time, the thickness of the amorphous ITO film 250 should be adjusted in consideration of the correlation with the transmittance of the amorphous ITO bar, preferably formed in the range of 200 ~ 2000Å. In addition, when a large amount of H ₂ is supplied, the specific resistance may be high. Therefore, the supply amount of H ₂ is preferably adjusted to an appropriate level.

That is, H ₂ increases the phase transition temperature from amorphous to crystalline, and increases porosity and amorphousness. This H ₂ blocks the oxygen pores and reduces the concentration of charge mobility.

In particular, the amorphous ITO film 250 has a high etching rate compared to the crystalline ITO film (150 in FIG. 2), which has the advantage of improving productivity. In the present invention, the amorphous ITO film 250 is patterned using oxalic acid instead of a mixture of nitric acid and hydrochloric acid. In this case, amorphous IZO may be used instead of the amorphous ITO.

When wet etching the amorphous ITO membrane 250 with a strong acid such as a mixture of nitric acid and hydrochloric acid, the reaction rate is so fast that the process is completed within a few seconds. When used, it is possible to control the etching rate without damaging the lower metal, and has an advantage of shortening the process time because the etching rate is good compared to crystalline ITO.

That is, the present invention not only prevents the crystallization of amorphous ITO even after the hard baking process of the photoresist and wet etching process using oxalic acid, but also increases the specific resistance of the metal film by adding H ₂ . It is possible to proceed a continuous film forming process that is not discontinuous.

In particular, since the amorphous ITO film 250 has lower electrical conductivity than the crystalline ITO film, the amorphous ITO film 250 and the metal film 260 are successively formed and patterned by wet etching using oxalic acid. The film 250 is crystallized by a high temperature process of 240 ° C. or higher.

As a result, the amorphous ITO film 250 and the metal film 260 can be continuously formed through the hybrid deposition equipment mounted in one deposition chamber, thereby reducing the number of deposition equipment mounted in the deposition chamber. Accordingly, the area of the clean room can be reduced in design.

6 is a process flowchart showing a thin film deposition method according to the present invention according to the process sequence.

As shown, the thin film deposition method according to the present invention is st1. Adding H ₂ on the substrate to form an amorphous ITO film. st2. And laminating a metal film on the substrate on which the amorphous ITO film is formed. In addition, st3. Applying a photoresist on a substrate in which the amorphous ITO film and the metal film are sequentially stacked. st4. Soft baking and developing the photoresist. st5. Hard baking the photoresist. st6. Patterning the metal layer by a first wet etching process. st7. The desired thin film may be formed by patterning the amorphous ITO film exposed under the metal film by a second wet etching process.

Figure 7 is a graph showing the crystallization tendency of the amorphous ITO film, the firing temperature according to the invention, more particularly, to test the addition of H ₂ O when the amorphous ITO deposition was measured through X-ray diffraction (X-Ray Diffractometer) Data.

As shown, the intensity is changed according to the diffraction angle (2θ) that is reflected by changing the temperature and adding H ₂ O during amorphous ITO deposition and irradiating X-rays at different angles. It is a graph comparing the value measured at 160 degreeC, 200 degreeC, 240 degreeC, 260 degreeC, and 350 degreeC when the said amorphous ITO membrane was formed at 140 degrees C or less, More specifically, 30-120 degreeC.

At this time, it can be seen that the crystal pig is gradually generated from 240 ℃, it can be confirmed that the crystallization is completely progressed at 260 ℃ or more.

That is, when H ₂ O or H ₂ is added in the process of depositing the amorphous ITO film as in the present invention, the crystallization temperature of the amorphous ITO film may be increased to 200 to 240 ° C.

Therefore, in the present invention, since the amorphous ITO film and the metal film can be continuously formed in one deposition chamber, productivity can be improved by reducing the initial equipment investment cost and the clean room area.

Up to now, the embodiment of the present invention has been described as an example of the continuous deposition of an amorphous ITO film and a metal film on the array substrate for a liquid crystal display device, but is not limited to this, in most display devices formed through a thin film deposition process It will be apparent to those skilled in the art that the application can be extended.

Therefore, it will be apparent that the present invention is not limited to the above embodiments, and various modifications and changes can be made without departing from the spirit and spirit of the present invention.

1 is a schematic cross-sectional view of a liquid crystal display according to the related art.

2 is a process flow diagram schematically illustrating a manufacturing process in an inline manner.

3 is a cross-sectional view schematically showing a state in which a crystalline ITO film and a metal film are discontinuously formed on a substrate.

4 is a process flow diagram schematically illustrating a manufacturing process carried out in an inline manner according to the invention.

5 is a cross-sectional view schematically showing a state in which an amorphous ITO film and a metal film are continuously formed on a substrate.

6 is a process flowchart showing a thin film deposition method according to the present invention according to the process sequence.

7 is a graph showing the crystallinity tendency according to the firing temperature of the amorphous ITO film according to the present invention.

* Explanation of symbols for the main parts of the drawings *

200: thin film deposition equipment 205: carrier

210: substrate 215: loader

220: heating chamber 225: load lock chamber

230: deposition chamber 240: cooling chamber

245: Unloader

Claims (6)

Adding H ₂ on the substrate to form an amorphous ITO film; Stacking a metal film on the substrate on which the amorphous ITO film is formed Thin film deposition method comprising a. The method of claim 1, And the amorphous ITO film and the metal film are patterned using different etchant. The method of claim 2, The etchant used in the patterning of the amorphous ITO film is oxalic acid. The method of claim 2, And patterning the amorphous ITO film, and crystallizing at a temperature of 240 to 350 ° C. A loader into which a substrate seated on a carrier upper surface is inserted; A heating chamber for preheating the substrate passing through the loader; A deposition chamber for continuously forming an amorphous ITO film and a metal film on the upper surface of the substrate exiting the heating chamber; A cooling chamber for cooling the substrate on which the crystalline ITO film and the metal film are formed; Unloader for transferring the substrate passed through the cooling chamber Thin film deposition apparatus comprising a. The method of claim 5, wherein Thin film deposition equipment, characterized in that to add H ₂ during the deposition process of the amorphous ITO film.

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