KR20090113109A - Composition of passivation and sputtering target and passivation membrane and manufacturing method of it - Google Patents

Abstract

PURPOSE: A composition of passivation, sputtering target, passivation membrane, and a manufacturing method thereof are provided to protect food contents against moisture and oxygen for a long period. CONSTITUTION: A composition of passivation is composed of 10-90 atomic weight% SiO2 and 90-10 atomic weight% ZnO. A passivation membrane is formed on top of a glass substrate or polymer substrate. The passivation membrane comprises 10-90 atomic weight% SiO2 and 90-10 atomic weight% ZnO. A method for manufacturing the passivation membrane comprises the following steps of: depositing the target or pellet comprising 10-90 atomic weight% SiO2 and 90-10 atomic weight% ZnO on an organic substrate or polymer substrate; and sputtering the deposited target or pellet to form the passivation membrane.

Description

Composition of passivation and sputtering target and passivation membrane and manufacturing method of it

The present invention relates to a passivation composition, a sputtering target and a passivation film using the same, which can be used for food packaging materials, OLEDs, solar cells, etc. due to low moisture and oxygen permeability.

Recently, displays for visually transmitting information have been diversified, and examples thereof include a cathode ray tube (CRT), a plasma display panel (PDP), a liquid crystal display (LCD), and an organic light emitting diode (OLED).

OLED has the advantages of low power consumption, wide viewing angle, and fast response speed, and it is thinned and large-area based on low cost and ease of manufacturing process, and overcomes the problems of luminous efficiency and lifespan for the commercialization of such OLED. OLEDs deteriorate in a matter of hours due to moisture permeation of oxygen and moisture transmitted through defects such as pinholes present in the cathode thin film. In addition, since high oxygen or moisture permeability of the polymer substrate is an obstacle to the application of the flexible display, the OLED is passivated to protect against moisture and oxygen permeation in the atmosphere. One passivation method is largely divided into a cap method using metal and glass and a thin film method using inorganic or organic materials.

Passivation with a metal or glass cap consists of a glass cap for the diffusion barrier, epoxy resin for fixing, and nitrogen for the internal environment, and more recently, Hygroscopic agents such as P ₂ O ₅ , BaO, CaO were attached inside the cap to remove moisture that is permeated through the sealant. Passivation using such a metal or glass cap shows excellent barrier properties, but recently, thin film passivation due to high cost due to the difficulty of manufacturing process and the penetration of moisture and oxygen through sealant Attempts are being made to apply the process.

Thin-film passivation technology is a new passivation process that protects OLEDs from moisture and oxygen in the air by passivating OLEDs in single or multiple layers using inorganic or organic thin films with very low moisture permeability. Among passivation thin film materials, Al has been widely used as a gas barrier in food and medical packaging since the early 1970s. Transparent gas barrier thin films of SiO _x and AlO _x have been developed since 1980 for use in microwave ovens and packaging applications that provide a visual indication of the contents. Recently, a thin nitride passivation film such as AlO _x N _y , SiN _x and SiO _x N _y is used for OLEDs such as thin nitride or nitric acid, which has low water transmittance (WVTR) and oxygen transmittance (OTR). Oxygen Transmission Rate) must be satisfied for this purpose.

First, the passivation layer formed at room temperature should have a dense amorphous structure. Formation of thin films at room temperature leads to the growth of three-dimensional islands, resulting in a dense microstructure with many macro crystals and nano crystals, and grain boundaries in the crystal structure. It is well known that grain boundaries can be a channel of moisture and oxygen permeation.

Second, the passivation layer must be large in polarity to effectively block moisture permeation. This is because moisture with a large dipole moment forms groups on the surface of the oxide film and pores with high polarity and prevents the continuous transmission of moisture. Since the polarity can be estimated as the refractive index, a passivation film having a large refractive index is required.

Third, the passivation film must have excellent optical transmittance in order to be applied to a flexible material using a top emission OLED and a polymer substrate. Unlike ordinary bottom emission OLEDs emitting light through transparent glass substrates, top emission OLEDs are very important for the integration of OLEDs with electronic devices. Top-emitting is desirable for active-matrix OLEDs because all circuits can be located at the bottom without interference from components such as transistors or wires. Therefore, the fabrication of transparent passivation film for top emitting OLED is one of the important technologies for long life OLED, and modulates the optical property of light emitted by using microcavity structure which requires transparent thin film such as high refractive index. It is possible to. Therefore, transparent passivation layers with high refractive index are more advantageous.

In order to realize flexible OLEDs, very low water transmittance (WVTR) and oxygen transmittance (OTR) of 10 ^-4 g / m ² .day or less and 10 ^-3 cc / m ² .day or less must be satisfied. .

Accordingly, sputtering or PECVD (Plasma Enhanced) is used for the use of oxynitride films, such as AlO _x N _y and SiO _x N _y , which have a relatively dense structure as the passivation thin film of OLED, compared to SiO _x and AlO _x . Chemical Vapor Deposition processes have been studied. However, these barrier films are known to have high WVTRs that are difficult to apply to the display industry. Therefore, in order to completely block moisture or oxygen permeation, it is necessary to develop a new passivation material having a very low moisture permeability.

These passivation properties verify the permeation prevention properties of water and oxygen. The permeation rate for water is evaluated in units of g / m ² -day and in units of cc / m ² -day for oxygen as described above. . The unit is a unit commonly used in various industries related to display, coating, and packaging, and the measurement is generally performed using a test apparatus of Mocon of USA. However, the measurement by this method must take a lot of time and money, and also using this method, there is a problem that it is difficult to make a precise measurement because the measurement limit is limited to 0.001 g / m ² -day.

On the other hand, the passivation is applied to not only OLED, but also solar cells, food packaging containers and the like.

As described above, the present invention provides a novel passivation material capable of effectively blocking moisture or oxygen permeation, using electron deposition and magnetron sputter cathode, FTS cathode, cylinder using SiO ₂ and ZnO composite oxide or Si and Zn composite. An object of the present invention is to provide an inorganic compound oxide passivation film (ICTF; Inorganic Compound Thin Film) by a sputtering method such as a cathode.

The passivation composition of the present invention for achieving the above object, in order to form an inorganic passivation film, SiO ₂ and ZnO is 10-90 atomic% and 90-10 atomic% or Si (10-90 atomic%) and It consists of Zn (90-10 atomic%).

In addition, a passivation film is formed on a glass substrate or a polymer substrate by a deposition method or a sputtering method using a target (pellet) composed of 10 to 90 atomic% and 90 to 10 atomic% of SiO ₂ and ZnO. A passivation film is formed on a glass substrate or a polymer substrate by a reactive sputtering method using a target composed of 90 atomic%) and Zn (90-10 atomic%).

In the above-described configuration, the electron beam deposition method forms a pellet using a glass former composed of SiO ₂ powder and a SiO ₂ powder and ZnO mixed powder as a glass modifier, and removes impurities from the glass substrate and the polymer substrate through a washing process. The pressure inside the chamber before deposition is maintained at 10 ^-5 torr or less using a high vacuum pump, and during deposition, the deposition process is performed between 10 ^-4 torr and 10 ^-5 torr. Cool.

Then, the sputtering method is formed as SiO ₂ glass powder, glass deformation as the initial vacuum ^10-5 by using the ZnO powder produced target, and remove the impurities of the glass substrate and a polymer substrate via a cleaning process, and using a high vacuum pump After maintaining the vacuum below Torr, plasma is formed in a pure argon (Ar) gas atmosphere in the 10 ^-3 Torr band, and presputtered for 5-15 minutes using a shutter during each deposition. sputtering).

In the sputtering method, the sputtering method is different from the above-described sputtering method, using Si powder as a glass former, Zn powder as a glass modifier, and simultaneously supplying oxygen and argon gas as reactive gases.

In the above configuration, when the SiO ₂ and ZnO mixed inorganic thin films are used as the passivation film, it is possible to provide a passivation film having a very low moisture and oxygen permeability.

Accordingly, the passivation film of the present invention can be applied to the flexible OLED, and when used in a food packaging container, the contents are protected from moisture and external air, thereby enabling long-term storage. In addition, the flexible solar cell can protect the contents from moisture and external air.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1. Inorganic by electron beam deposition Passivation  Thin film formation method

(One) Pellets  making

The electron beam deposition pellets for the production of the inorganic composite thin film were selected from SiO ₂ powder (99.99%) having a large optical band gap and a small refractive index as a glass former. SiO ₂ powder with high refractive index and polarity with 99.99% purity and ZnO powder classified as glass modifier with high polarity of 2.859 Å ³ with small optical band spacing were mixed and mixed at various ratios, respectively. After evaporating water for 60 minutes in a vacuum oven (JEIO TECH) and mixing for 2 hours using a ball mill (Jisco), an electric furnace of 800 ° C. (DAE RYUN CO CO) is used to minimize the deformation of the mixture. Heat treatment was performed for 90 minutes. After the heat-treated mixture was stirred and pulverized through a hand mill process, and then mixed again using a ball mill for 24 hours. Using a hydraulic press (Carver) to produce a pellet (pellet) having a diameter of 1cm, after the heat treatment process at 1100 ℃ for solidification was used after slowly cooling the temperature for 24 hours.

(2) substrate cleaning

As a substrate for thin film deposition, a glass (sodalime glass) substrate and PEN (polyethylene naphthalate) were used. The glass and PEN substrates are 25 x 75 mm ² and 50 x 50 mm ^2, respectively. Impurities and oxides on the surface of the substrate reduce the phenomenon of peeling, pinholes, and adhesion of the film, so in order to remove impurities on the substrate, acetone (5 minutes), alcohol (5 minutes), distilled water (2 minutes) in order to remove impurities After ultrasonic cleaning, the surface was completely dried to remove moisture and dust. Finally, after confirming that foreign matter remained on the surface of the substrate by using a microscope, it was wrapped and used in a lactic acid paper.

(3) deposition process of inorganic thin film

In the present invention, a general electron beam evaporator was used, and the thin film was fabricated on a glass substrate and a PEN substrate. The boat used a crucible made of graphite, and the deposition was maintained at a distance of 18 cm between the boat and the substrate, the emission current for the electron beam emission was 10 mA, and the acceleration voltage was 4 KV. At this time, the thickness of the thin film was controlled using the FTM5-oscillator.

The vacuum before deposition was maintained below 10 ^-5 torr using a high vacuum pump, and the pressure during deposition was maintained between 10 ^-4 torr and 10 ^-5 torr. After the deposition, the film was naturally cooled while maintaining a high vacuum for 60 minutes in order to prevent an increase in stress of the thin film due to sudden cooling.

Then, an element layer is formed on a glass substrate or a polymer substrate such as PEN, PI, PC, PET or the like, and a passivation film is vacuum deposited.

(4) measuring method

The calcium cells produced by the electron beam deposition method are completely opaque. However, when the calcium cells are exposed to the atmosphere, they become transparent while absorbing the moisture contained in the atmosphere, which gradually changes with the elapsed time in the atmosphere. The calcium cell gradually becoming transparent with the exposure time in the atmosphere causes a change in the light transmittance in the visible light region, and shows the maximum light transmittance when the water absorption of the calcium cell is completely saturated. Therefore, when a calcium cell has a passivation film, the passivation film delays the absorption of moisture of the calcium cell, which in turn saturates the saturation time (the time at which the light transmission spectrum no longer changes) when the light transmittance of the calcium cell is maximized. Results in delays. Therefore, by comparing the saturation time of the light transmission spectrum of the calcium cell having the inorganic thin film as the passivation layer, it is possible to evaluate the water permeation characteristics of the inorganic thin film.

Therefore, calcium cells with a passivation layer to confirm moisture transmittance show the step of progressively transparent Ca thin film as a function of time of exposure to the atmosphere as a change in the light transmission spectrum in visible light. The moisture permeation prevention properties of the passivation layers were evaluated by comparing them with the measured moisture permeability results.

For the calcium test (Ca test) in the present invention was used a glass substrate (soda lime glass), the calcium cell (Ca cell) on the glass substrate using an electron beam deposition method having a size of 10 x 20mm ² and a thickness of about 200 nm After the deposition, the passivation thin film was then deposited to a thickness of about 400 nm to prevent moisture permeation.

The deposition conditions of the calcium cell and the passivation thin film are shown in Table 1 and Table 2, respectively.

(5) results

i) without passivation film

FIG. 1 shows the change in the light transmission spectrum at two minute intervals after forming only a calcium cell with a thickness of 200 nm without a passivation layer on a glass substrate and exposed to the atmosphere. The saturation time is 14 minutes.

On the other hand, the water absorption process of the calcium cells left in the air can be represented by the following formula.

According to the above formula, it can be seen that 2 mole of H ₂ O is required in order for 1 mole of calcium cells to be completely transparent.

ii) When a single inorganic material is used as the passivation film

FIG. 2 shows the change in the light transmission spectrum of the calcium cell having a single inorganic thin film as the passivation film according to the exposure time in the air, and the saturation time is different for the calcium cell having the SiO ₂ and ZnO single inorganic passivation film, respectively. It appears as 22 and 8 minutes, and a single inorganic thin film is evaluated as having a very low moisture permeation prevention effect as a passivation film.

In general, vapor atoms or molecules condense during the growth of a thin film, and the deposition method (Thermal Evaporation, Sputtering, Ion Beam Assisted Deposition, PECVD) and deposition conditions (substrate temperature, deposition rate, pressure) Depending on the mobility of the deposited species (ad-atom), their equilibrium position is reached and diffused on the thin film surface. In general, low-mobility deposition of deposited species, such as thermal deposition and electron beam deposition, freezes the deposited species at the moment they impinge on the substrate, preventing them from reaching or diffusing to the equilibrium site. The result is an open structure consisting of pores between the spherical grains and the grains, which act as a major channel of water and oxygen permeation. Therefore, the single inorganic thin films formed by the moisture or oxygen electron beam evaporation method of the passivation film exhibit an essentially low deposition type energy structure. Therefore, despite the deposition on the substrate under the same conditions, it was found that the moisture permeability was greatly affected by the adhesion between the substrate and the inorganic thin films, the surface roughness, and defects such as pores and pinholes. In order to solve the problems of such single inorganic thin films, inorganic composites in which a single inorganic material is mixed in various ratios are used.

iii) Inorganic composite thin film used as passivation film

In order to solve the problems of single inorganic thin films, SiO ₂ was selected as a glass former, and SiO ₂ and ZnO is mixed so that the ratio x of ZnO has 0, 10, 30, 50, 70, 90, 100 atomic% of the total atomic weight of the glass former and the glass modifier to prepare inorganic composite thin films. Investigate.

FIG. 3 shows the change in the time-dependent light transmittance spectrum in the atmosphere for a calcium cell using x = (a) 30, (b) 50, (c) 70 atomic percent thin films deposited on a glass substrate as a passivation layer. The saturation times of the inorganic composite thin films of x = 30 and 70 atomic% were shown as 130 and 540 minutes, respectively, whereas the thin films of x = 50 atomic% were not fully saturated even after 660 minutes. This shows that x = 30 and 70 atomic% thin films have an average transmittance of 80% in the visible region after saturation time, but the average transmittance is far less than 80% after 660 minutes in x = 50 atomic% thin films. As described above, it was confirmed that the moisture permeability of the inorganic composite thin film could be significantly improved according to the mixing ratio. In particular, the thin film having x = 50 showed the best water permeation prevention effect.

And, as can be seen in the MOCON TEST of FIG. 4, x = 50 composite thin film has a moisture permeability of 10 ^-3 g / m ² -day or less and an oxygen permeability of 10 ^-3 cc / m ² -day or less , Which is consistent with the calcium test.

5A and 5B are two-dimensional (left) and three-dimensional (right) AFM images of thin films deposited on a glass substrate with x = 0, 10, 30, 50, 70, 90, 100 at.%.

The SiO ₂ thin film of (a) or the ZnO thin film of (g) results in an open structure composed of spherical grains and pores between the grains. The pores will act as a major channel of water and oxygen permeation. Therefore, in order to improve the water or oxygen permeation prevention effect of the passivation layer, it may be said that a method of minimizing pores or pinholes that may easily appear in the thin film process by electron beam deposition may be applied.

In general, in the case of the inorganic thin film, when the ions are bonded or participate in the thin film composition, the density of the thin film may be increased. However, in order to form such an ion-assisted structure, very high energy must be applied to the thin film. Therefore, the inorganic material is mixed by using an electron beam evaporator and increasing the density of the inorganic thin film by a low temperature process. As shown in (b)-(f), inorganic composite thin films have a much more compact structure than SiO ₂ or ZnO thin films, and thus, their passivation density can be seen to be greatly improved.

In order to apply a composite thin film as a passivation layer of an OLED, in addition to low moisture permeability and oxygen permeability, their structural characteristics and transmittance in the visible region are also important factors.

6 shows (a) light transmission spectrum and (b) X-ray diffractometer (XRD) results of SiO ₂ , ZnO deposited on a glass substrate, and thin films added with SiO ₂ and ZnO at 50:50.

In (a), the ZnO thin film having a smaller optical band spacing than the SiO ₂ thin film can be seen that the light transmittance is very poor while the absorption edge of the light transmission spectrum moves largely toward the long wavelength. The light transmittance of the ₂ and ZnO 50:50 mixed thin films is very good (average 90%) in the visible region, and is similar to that of the SiO ₂ thin film.

In addition, as can be seen from the XRD pattern shown in (b), it can be confirmed that it has an amorphous structure in which no peak showing crystallinity can be found.

7 and 8 show the moisture permeability and light transmittance of the PEN substrate instead of the glass substrate in the passivation using the above-described calcium test glass substrate, Max and Min in FIG. The minimum axis represents the multiplier of 10 and the horizontal axis represents the mixing ratio.

In FIG. 7 and FIG. 8, the moisture permeability and the light transmittance of the composite membrane film mixed with SiO ₂ and ZnO 35:65 showed the lowest moisture permeability and excellent light transmittance.

Therefore, SiO ₂ and ZnO composite inorganic thin films produced by electron beam deposition are low water permeability and oxygen permeability that can be sufficiently applied as a passivation layer of OLED, and excellent passivation or gas barrier properties can be obtained. When applied simultaneously with the use of monolayers and organic layers (primers or peninsins) to overcome the effects of film cracking, it is possible to meet the low moisture and oxygen transmission rates required for OLEDs or flexible substrates.

2. RF - Magnetron Sputtering method  by Passivation  Layer formation method

Compared to the electron beam deposition method described above, sputtering or chemical vapor deposition (CVD) generally reduces the size of the pores formed in the thin film by the deposition species having high mobility, and consequently reduces the passivation density (density of the thin film). Since it is possible to form a thin film having a fine structure that can effectively block the permeation of moisture and oxygen through the thin film, the following describes a method of forming a passivation layer using the RF-magnetron sputtering method.

(One) target  making

As a glass former for the target fabrication, a glass modifier was selected as a glass modifier of SiO ₂ powder having a size of 100 nm (99.999%) and ZnO powder having a size of 1 μm having a high refractive index and polarity (99.999%). SiO ₂ was mixed evenly for 24 hours using a ball mill to have 100-X atomic% and ZnO at X atomic% by X = 0, 10, 30, 50, 70, 90 atomic%. After agitation by a ball mill, a hand mill (Hand Mill) for directly stirring and pulverizing by hand in a mortar and pestle was performed for 2 hours, thereby preparing SZO mixed inorganic materials for each composition ratio.

The sintered SZO powder was sintered at 600 ° C. for 2 hours to remove moisture contained in the SZO mixed minerals evenly mixed according to the composition ratios. The sintered SZO powder was again pressed, crushed, hand milled, The sputter target was repeatedly manufactured in the order of resintering, recompression, and solidification. The final solidification process was carried out at 1000 ° C. for 2 hours and naturally cooled to minimize deformation.

(2) substrate cleaning

In order to reduce the peeling phenomenon and the pinhole phenomenon of the oxide thin film by cutting the PEN used as the substrate to the size of 50 × 50 mm, impurities were removed by ultrasonic washing in the order of distilled water and alcohol. The ultrasonically cleaned substrate was again blown with nitrogen (N _{2 )} gas to remove moisture and dirt from the surface. Finally, use a microscope to check the surface for debris and seal it with lactic acid paper.

(3) SZO  deposition

The sputtering system of the present invention is a combination of DC and RF, it is possible to maintain a vacuum of 10 ^-6 Torr by using a high vacuum pump as a vacuum system. All SZO thin films deposited on PEN substrates were deposited at room temperature in pure Argon (Ar) gas atmosphere of 2x10 ^-3 Torr, RF Power is 50 watts, and the distance between target and substrate is 7cm. In each deposition, pre-sputtering (pre-sputtering) is performed for 10 minutes using a shutter, and the deposition conditions are shown in Table 3.

(4) measuring method

Calcium test was used to investigate the passivation characteristics of SZO inorganic composite thin films. After thermal evaporation of calcium cells to a size of 10 x 20 mm ² on a glass substrate (sodalime glass), inorganic composite thin films were deposited thereon as a passivation layer to prevent moisture permeation. The applied RF power was fixed at 50 watts and the deposition time was 120 minutes.

The film formation characteristics of the SZO thin film show that the thickness of the thin film increases as the ZnO component increases. When x exceeds 30 atomic%, the thin film thickness rapidly increases. The increase in the thickness of the SZO thin film according to the ZnO component may be explained as the sputtering yield of ZnO is larger than that of SiO ₂ and the deposition rate increases accordingly. Therefore, the uniformity of the thickness of the SZO thin films having different composition ratios is possible by controlling the deposition time according to the composition ratios.

The SiO ₂ and ZnO single inorganic thin films deposited by the sputtering method were found to have a value of 1 × 10 ² g / m ² -day as a result of WVTR measurement, indicating that they were not suitable for use as a passivation layer of OLEDs.

9 are water absorption characteristics of calcium cells passivated with inorganic composite thin films having SiO ₂ of 100-x atomic% and ZnO of x atomic% (x = 10, 20, 30, 40), respectively (a), ( b), (c) and (d).

SZO inorganic composite thin film can be seen that the water permeation characteristics are significantly different depending on the composition ratio. When the ZnO components x = 10, 20, 30, 40 thin films were used as passivation layers, the respective saturation times were measured at 40 minutes, 110 minutes, 360 minutes and 2,160 minutes.

Therefore, considering that the saturation times of the pure calcium cells are all similar to 10 minutes, it can be seen that the SZO mixed inorganic thin film significantly improves the water permeation prevention effect as the ZnO component is increased.

Particularly, in the case of a thin film of 50:50 atomic% mixed with SiO ₂ and ZnO shown in FIG. 10A, the saturation time is almost 72 hours, which is 532 times higher than that of the calcium cell in which the passivation film is not formed. You can see the increase.

(b) shows the change in light transmittance as a function of atmospheric exposure time at a wavelength of 550 nm to compare the passivation characteristics according to the composition ratio of mixed inorganic thin films including a single inorganic thin film. First, in the case of a single inorganic thin film, after the saturation time (about 40 minutes) of the calcium cell with the SiO ₂ passivation layer, it can be seen that the light transmittance hardly changes at 80%, which is a mixed inorganic of x = 10 and 30 It also shows that the light transmittance saturates at almost 80% even in thin calcium cells. However, in the case of ZnO thin films, the light transmittance saturates around 50%, since the light transmittance of the ZnO thin film itself is significantly lower than that of other inorganic thin films. On the other hand, in the case of x = 50, it was impossible to observe the saturation time within the measurement time, but it was confirmed above that it took about 3 days for the light transmittance to reach 80%. On the other hand, in the case of x = 70 and x = 90, it may take several months for the light transmittance to reach 80%. The reason is that except for ZnO, the light transmittances of all the SZO mixed inorganic thin films themselves are about the same.

Figure 11 (a) is a passivation layer showing the water absorption characteristics of the calcium cell having an inorganic composite thin film of x = 70 and x = 90, respectively, (b) is a photograph of the actual appearance of the sample over time As shown.

In the case of the passivation layer of x = 70 in (a), the light transmittance in the wavelength region of 400 nm or more does not exceed 0.2% even after 14 days have elapsed. This can be interpreted that little water is absorbed by the calcium cells through the passivation layer. In addition, after one month, the light transmittance was maintained at 1% or less, making it difficult to measure the saturation time even after three months. In this sample, the saturation time of a calcium cell (hereinafter referred to as Bare calcium cell) where no passivation film was formed was about 30 minutes. This is a thousand-fold increase in saturation time due to the SZO passivation layer with x = 70, compared to the saturation time of bare calcium cells, given that the calcium cells were deposited relatively thick compared to other passivation layers. It can be evaluated that the water permeation prevention effect is excellent.

On the other hand, an increase of more than a thousand times compared to the saturation time of pure calcium cells is also observed in the passivation layer having x = 90 shown in (a). For this sample, the saturation time of the bare calcium cell is about 17 minutes and the thickness of the passivation layer is about 800 nm. A change in light transmittance over 14 days shows a light transmittance change of less than 0.5% at wavelengths above 400 nm. Light transmittance peaks appearing at wavelengths below 400 nm are presumed to be due to reference errors and non-uniform moisture absorption of calcium cells in the measurement. Non-uniform water absorption of the calcium cells can be confirmed in the form of the sample with elapsed time shown in (b). After 12 hours, the water absorption of the calcium cells can be seen to occur from the lower right corner of the sample, and as time passes, the absorption region is gradually enlarged. In particular, since the calcium cell used in the present invention was manufactured in consideration of the light transmittance measurement, it was manufactured relatively large, and thus water absorption of the calcium cell after passivation mainly shows the common point occurring first at the corner of the calcium cell, which is the passivation. It is considered reasonable to evaluate in the part except the edge area by layer.

12 shows light transmission spectra of various inorganic thin films deposited to a similar thickness on a glass substrate. Inorganic thin films of less than x = 90 show very good light transmittance of more than 85% in the visible region, while ZnO thin films have a slightly reduced light transmittance and a large absorption wavelength compared to other thin films. You can see it moved. From the above experimental results, it can be seen that the SZO inorganic composite thin film can significantly improve the WVTR and OTR characteristics according to the composition ratio, the thickness of the thin film, and the deposition method when compared with the single inorganic thin films. In particular, x = 70 And 90 SZO inorganic composite thin films have a water transmittance of 10 ⁻³ g / m ² .day or less.

13A and 13B illustrate XRD patterns for analyzing crystallinity of thin films according to composition ratios of SZO thin films. Here, using an X-ray diffraction apparatus using a Cu-Ka (1.54) line, it was measured by 2θ scan under a condition of 40 kV and 100 mA in a 20 ° -80 ° section. (b) The thin film can confirm the crystal peak indicating the structure of hexagonal wurtzite in the vicinity of 2θ = 33 ^o , whereas SiO ₂ is an amorphous structure. It is common practice to have a dense amorphous structure for application as a passivation of an OLED or as a gas barrier layer of a FOLED. ZnO has been identified as a passivation layer in various functional aspects, but has a crystal structure, a low transmittance in the visible region, and a small optical band spacing. On the other hand, the SiO ₂ thin film has a large optical band gap and a light transmittance amorphous structure, but has a disadvantage in that the water transmittance is large due to the coarse structure.

Therefore, in the present invention, by fabricating an inorganic thin film of SiO ₂ and ZnO, a mixed inorganic thin film having a high density in a dense amorphous structure such as (c) (d) (e), a wide optical band spacing, a high transmittance in the visible region and a polarity By overcoming the shortcomings of the SiO ₂ and ZnO thin films, it was confirmed that the material is very suitable as a passivation layer and a gas barrier layer of the OLED.

3. Comparison of Characteristics of Inorganic Composite Thin Films According to Process Methods

FIG. 14 shows AFM images of a SiO ₂ thin film and (SiO ₂ ) ₅₀ (ZnO) ₅₀ thin film deposited on a glass substrate by (a), (b) electron beam deposition and (c) and (d) RF-magnetron sputtering. will be. In general, vapor atoms or molecules condense during thin film growth and are determined by deposition method (Thermal Evaporation, Sputtering, Ion Beam Assisted Deposition (PECVD)) and deposition conditions (substrate temperature, deposition rate, pressure). Depending on the mobility of the ad-atom (deposited species), they reach their equilibrium position and diffuse onto the thin film surface. In general, deposition with low ad-atom mobility, such as thermal deposition and electron beam deposition, freezes the ad-atoms as they impinge on the substrate, preventing them from reaching or diffusing to the equilibrium site. As a result, in FIG. 13A, an open structure composed of spherical grains and pores between the grains, such as a SiO ₂ thin film, is obtained. The pores will act as a major channel of water and oxygen permeation. Therefore, in order to improve the moisture or oxygen permeation prevention effect of the passivation layer, a method for minimizing the pores or pinholes that can easily appear in the thin film process should be applied.

The sputtering process can increase the compactness of the thin film in this context. As can be seen from FIG. 13, inorganic thin films formed by electron beam deposition method, inorganic thin films formed by sputtering method than those of FIGS. 13A and 13B, structures (c) and (d) of FIG. 13 are much denser. It can be seen that The compactness of this structure is also apparent in terms of the moisture permeation prevention effect, the results can be seen in FIG.

FIG. 15 compares calcium test results of SZO thin films mixed at 50: 50 atomic% by (a) electron beam deposition and (b) sputtering. Here the calcium cells and passivation layers are made of the same thickness. The saturation time of the calcium cell with the passivation layer deposited by electron beam deposition was 660 minutes (11 hours), while the saturation time of the calcium cell with the passivation layer deposited by sputtering was 4,320 minutes (72 hours). By showing, it can be seen that it has a much improved water permeation prevention effect compared to the former.

As such, the reason for the difference in moisture permeability according to the process method of the mixed inorganic thin film will be described.

Mixed inorganic thin films deposited on calcium cells adsorb water molecules with large dipole moments and lone-pair electrons at the top surface and the inner surface of the pores to produce OH groups at the surface. In particular, the addition of ZnO with polarizability and refractive index results in the formation of high density OH groups by strong action with moisture at the inner surface of the pores. The OH group formed in the pores binds with the moisture that has penetrated, which prevents continuous moisture permeation and consequently reduces the moisture permeability.

If the pores have a size of 1 nm or more, the permeated moisture penetrates the thin film with little interaction through the middle of the pores away from the OH group on the inner surface of the pores, which is a mixed inorganic film deposited by electron electron beam deposition. It can happen in thin films. However, in the case of the mixed inorganic thin film formed by sputtering, if the structure becomes more dense and the pores in the thin film have a size of 1 nm or less, the water penetrated strongly with the OH group even considering that the diameter of the water molecules is 0.33 nm. And moisture permeation through the thin film will be effectively blocked.

Therefore, it can be seen that the SZO composite inorganic thin film manufactured by the sputtering method is a material having low moisture permeability and oxygen permeability, which can be sufficiently applied as a gas barrier layer of a FOLED substrate as well as a passivation thin film of OLED.

In conclusion, high passivation ZnO having high polarity is mixed with SiO ₂ , a glass former, to form a film by sputtering, and thus, excellent passivation or gas barrier properties can be obtained and moisture and oxygen permeability required by OLED or flexible substrate can be obtained. It seems to be able to satisfy.

On the other hand, the reactive sputtering method is the same as the RF-Magnetron sputtering method described above, except that oxygen and argon are simultaneously injected into the reactive gas using Si and Zn. After the target is manufactured, the impurities in the glass substrate and the polymer substrate are removed through a washing process, and a high vacuum pump is used to maintain a vacuum of 10 ^-5 Torr in the initial vacuum, and then 2x10 ^-5 Torr in the 10 ^-3 Torr band. Plasma is formed by forming a plasma in an oxygen and argon (Ar) gas atmosphere, and pre-sputtering (pre-sputtering) is performed for 5-15 minutes using a shutter during every deposition.

Accordingly, the result is also the same as the sputtering method, so detailed description is omitted to avoid duplication of description.

In addition, if a gap occurs in the passivation film composed of 10 to 90 atomic% and 90 to 10 atomic% of SiO ₂ and ZnO, the passivation film is not perfect, and thus the passivation film is protected. At least one organic film selected from a primer or phenolic series is formed on the upper layer to form a passivation film having a multilayer structure. The organic film is coated by a dry or wet coating method, and the passivation film is deposited as described above. Coated with sputtering or the like to form a passivation film and an organic film on the substrate, each having a layer structure having five layers or less.

FIG. 1 shows the change in the light transmission spectrum at two minute intervals after forming only 200 nm thick calcium cells without a passivation layer on a glass substrate.

Figure 2 shows the change in the light transmission spectrum of the calcium cell having a single inorganic thin film as the passivation film according to the exposure time in the atmosphere.

FIG. 3 shows the change in the time-dependent light transmittance spectrum in the atmosphere for a calcium cell using x = (a) 30, (b) 50, (c) 70 atomic percent thin films deposited on a glass substrate as a passivation layer.

4 shows (a) WVTR and (b) OTR graphs for thin films deposited at 400 nm thickness on a PEN substrate.

5A and 5B are two-dimensional (left) and three-dimensional (right) AFM images of thin films with x = 0, 10, 30, 50, 70, 90, 100 atomic percent deposited on a glass substrate.

6 shows (a) light transmission spectrum and (b) X-ray diffractometer (XRD) results of SiO ₂ , ZnO deposited on a glass substrate, and thin films added with SiO ₂ and ZnO at 50:50.

7 shows the moisture permeability in the case of passivation using a PEN substrate.

8 shows light transmittance in the case of passivation using a PEN substrate.

FIG. 9 shows water absorption characteristics of calcium cells passivated with inorganic composite thin films having SiO ₂ of 100-x atomic% and ZnO of x atomic% (x = 10, 20, 30, 40).

10A illustrates a case where SiO ₂ and ZnO are 50:50. The graph shows the change in the light transmission spectrum, and (b) shows the change in the light transmittance according to the exposure time in the air at a wavelength of 550 nm for the SiO ₂ and ZnO passivation films of various composition ratios.

Figure 11 (a) is a passivation layer showing the water absorption characteristics of the calcium cell having an inorganic composite thin film of x = 70 and x = 90, respectively, (b) is a photograph of the actual appearance of the sample over time Represented by

12 shows light transmission spectra of various inorganic thin films deposited to a similar thickness on a glass substrate.

13A and 13B illustrate XRD patterns for analyzing crystallinity of thin films according to composition ratios of SZO thin films.

FIG. 14 shows AFM images of a SiO ₂ thin film and (SiO ₂ ) ₅₀ (ZnO) ₅₀ thin film deposited on a glass substrate by (a), (b) electron beam deposition and (c) and (d) RF-magnetron sputtering. will be.

FIG. 15 compares calcium test results of SZO thin films mixed at 50: 50 atomic% by (a) electron beam deposition and (b) sputtering.

Claims (9)

A passivation composition comprising SiO ₂ and ZnO in an amount of 10-90 atomic% and 90-10 atomic%. A passivation film formed over an organic substrate or a polymer substrate, wherein SiO ₂ and ZnO are composed of 10-90 atomic% and 90-10 atomic%. A passivation film is formed by depositing and sputtering on an organic substrate or a polymer substrate by using a target or pallet composed of 10 to 90 atomic% and 90 to 10 atomic% SiO ₂ and ZnO. Ionization film production method. The electron beam deposition method of claim 3 SiO ₂ powder glass former and SiO ₂ powder and ZnO mixed powder are used as glass modifiers to form pellets, and the impurities are removed from the glass substrate and polymer substrate through the washing process, and inside the chamber before deposition using a high vacuum pump. The pressure is maintained at 10 ⁻⁵ torr or less, and during deposition, the passivation film is gradually cooled while maintaining the vacuum state after performing the deposition process by maintaining it between 10 ⁻⁴ torr and 10 ⁻⁵ torr. Manufacturing method. The method of claim 3, wherein the sputtering method A target is fabricated using SiO ₂ powder as a glass former and ZnO powder as a glass modifier, The cleaning process removes impurities from the glass substrate and the polymer substrate, After maintaining a vacuum of 10 ^-5 Torr in the initial vacuum using a high vacuum pump, plasma is formed by depositing a plasma in a pure argon (Ar) gas atmosphere of 2x10 ^-5 Torr in a 10 ^-3 Torr band, A method of manufacturing a passivation film, characterized in that pre-sputtering is performed for 5-15 minutes using a shutter during every deposition. A method of manufacturing a passivation film, comprising forming a passivation film on an organic substrate or a polymer substrate by a reactive sputtering method using a target composed of 10-90 atomic% and 90-10 atomic% by weight of Si and Zn. The method of claim 6, wherein the reactive sputtering method is A target is manufactured by using Si powder as a glass former and Zn powder as a glass modifier. The cleaning process removes impurities from the glass substrate and the polymer substrate, After maintaining a vacuum of 10 ^-5 Torr in the initial vacuum using a high vacuum pump, plasma is formed by forming a plasma in an oxygen and argon (Ar) gas atmosphere of 2x10 ^-5 Torr in a 10 ^-3 Torr band, A method of manufacturing a passivation film, characterized in that pre-sputtering is performed for 5-15 minutes using a shutter during every deposition. A multi-layered passivation film comprising a passivation film composed of 10 to 90 atomic% and 90 to 10 atomic% SiO ₂ and ZnO and at least one organic material film selected from a primer or phenolic series. A sputtering target, wherein Si and Zn are 10-90 atomic% and 90-10 atomic% or SiO ₂ and ZnO are 10-90 atomic% and 90-10 atomic%.

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