KR100658759B1 - Screener design method and screener manufactured by the same method - Google Patents

Abstract

A screener designing method and a screener manufactured by the same method are provided to improve a layer thickness uniformity below 3 percent by designing the screener with applying a regular designing rule according to an offset value. A screener designing method includes the steps of: setting a height from an evaporation source to a substrate and an offset value of the evaporation source; determining a plurality of measurement points, differing in a distance for a radius direction from a center of the substrate; forming a data sheet by calculating a deposition ratio of deposition material, deposited on the plurality of measurement points, while revolving the substrate about 2 pis; producing the added value by adding the deposition ratio with respect to each of the plurality of measurement points; on the basis of the measurement point, representing the minimum added value, adjusting the added value for making the added values of the remaining measurement points included within the predetermined uniformity with transforming the deposition ratio into 0 in a direction of from the point, where the rotational angle is pi, to the point, where the rotational angle is increasing or decreasing; and designing the screener as the same shape with the area where the deposition ratio is transformed into 0.

Description

Screener design method and screener manufactured by this method {SCREENER DESIGN METHOD AND SCREENER MANUFACTURED BY THE SAME METHOD}

1 is a process block diagram showing a screener design method according to an embodiment of the present invention.

2 is a data sheet created by calculating the deposition rate when the offset value F of the evaporation source is 0. FIG.

3 is a data sheet created by adjusting the data of FIG. 2 according to the method of FIG. 1 to design a screener.

4 is a plan view of a screener manufactured using the data sheet of FIG. 3.

5 is a data sheet created by calculating the deposition rate when the offset value F of the evaporation source is 30 cm.

6 is a data sheet created by adjusting the data of FIG. 5 according to the method of FIG. 1 to design a screener.

7 is a plan view of a screener manufactured using the data sheet of FIG. 6.

8 is a data sheet created by calculating the deposition rate when the offset value F of the evaporation source is 60 cm.

9 is a data sheet created by adjusting the data of FIG. 8 according to the method of FIG. 1 to design a screener.

FIG. 10 is a plan view of a screener manufactured using the data sheet of FIG. 9. FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screener for use in an organic vapor deposition apparatus, and more particularly, to a screener and a method of designing the screener capable of improving film thickness uniformity deposited on a substrate.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such flat panel displays include Liquid Crystal Display (LCD), Field Emission Display (FED), Plasma Display Panel (PDP) and Organic Light Emitting Display (PDP). Etc.

Among these, the organic light emitting diode display uses a phenomenon in which electrons and holes injected through a cathode and an anode are recombined to form an exciton in an organic thin film, and light of a specific wavelength is generated by energy from the formed excitons. It is a light emitting display device. Such an organic light emitting diode display has advantages of being able to be driven at a low voltage, being lightweight, thin, having a wide viewing angle, and having a fast response speed.

The organic light emitting diode of the organic light emitting diode display is also called an organic light emitting diode (OLED) because of its diode characteristics, and includes an anode electrode, an organic layer, and a cathode electrode which are stacked on a substrate.

The organic layer includes an organic emission layer (EML), in which holes and electrons recombine to form excitons and light is generated.

In order to increase the light emission efficiency, holes and electrons must be more smoothly transported to the organic light emitting layer. To this end, an Electron Transport Layer (ETL) may be disposed between the cathode electrode and the organic light emitting layer, and a Hole Transport Layer (HTL) may be disposed between the anode electrode and the organic light emitting layer, and the anode electrode and A hole injection layer (HIL) may be disposed between the hole transport layer, and an electron injection layer (EIL) may be disposed between the cathode electrode and the electron transport layer.

In general, a general method of forming a thin film on a substrate includes physical vapor deposition (PVD), such as vacuum evaporation, ion plating, and sputtering, and chemical vapor deposition by gas reaction. Vapor deposition (CVD).

Among these, the vacuum vapor deposition method is mainly used for formation of the thin film layer containing the organic film of an organic light emitting element.

In a general deposition apparatus for depositing an organic film using a vacuum deposition method, a substrate is mounted on an upper portion of the deposition chamber, a crucible containing a deposition material is disposed below the deposition chamber, and a heat source for evaporating the deposition material outside the crucible. As a heating wire is arranged.

The substrate is then rotated at a constant rotational speed during the deposition process of the deposition material.

By the way, when the organic film is deposited on the substrate using the vapor deposition apparatus having the above-described configuration, the thickness uniformity of the organic film has a great influence on the luminance uniformity and the reliability of the display device, so it must be strictly managed.

Thus, although the thickness uniformity of the organic film is conventionally managed at about 5%, it is necessary to manage the above-mentioned thickness uniformity to 3% or less in order to improve the luminance unevenness and to ensure stability.

In general, the deposition rate at any location on the substrate is known to be largest at the center of the substrate. Therefore, the thickness of the organic film deposited on the substrate is the thickest at the center of the substrate.

In order to improve the decrease in thickness uniformity caused by such deposition characteristics, conventionally, the evaporation source (the crucible) is installed in a state offset by a certain distance from the center of the substrate, but even in this case, there is a limit in improving the thickness uniformity. have.

In recent years, efforts have been made to improve thickness uniformity by using a screener.

However, until now, the screener is not manufactured according to a certain design rule, but is manufactured in a spherical manner based on the operator's experience. Therefore, there is a limit in improving the thickness uniformity using the screener.

The present invention has been made to solve the above problems, and an object thereof is to provide a screener and a method of designing the screener that can improve thickness uniformity.

In order to achieve the above object, the present invention provides a method that can effectively design the screener.

According to the design method according to the embodiment of the present invention, there is an effect that can produce a screener having a uniformity of 3% or less, in particular 1% or less.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a process block diagram showing a screener design method according to an embodiment of the present invention, Figure 2 is a data sheet created by calculating the deposition rate when the offset value (F) of the evaporation source is 0, Figure 3 is a screener 1 is a data sheet created by adjusting the data of FIG. 2 according to the method of FIG. 1, and FIG. 4 is a plan view of a screener manufactured using the data sheet of FIG. 3.

FIG. 5 is a data sheet prepared by calculating the deposition rate when the offset value F of the evaporation source is 30 cm, and FIG. 6 adjusts the data of FIG. 5 according to the method of FIG. 1 to design a screener. It is a created data sheet, and FIG. 7 is a top view of the screener manufactured using the data sheet of FIG.

8 is a data sheet created by calculating the deposition rate when the offset value F of the evaporation source is 60 cm, and FIG. 9 adjusts the data of FIG. 8 according to the method of FIG. 1 to design a screener. It is the created data sheet, and FIG. 10 is a top view of the screener manufactured using the data sheet of FIG.

A screener design method according to an embodiment of the present invention is to calculate the deposition rate of the deposition material deposited at any measurement point on the substrate, to create a data sheet using the calculation result, and to design the screener using the data sheet It features.

More specifically, the height between the evaporation source and the substrate is H, the offset value of the evaporation source is F, the cycle at which the substrate rotates one turn is T, and the distance from the center of the substrate to the measurement point is r. While the point is rotated by one rotation, that is, 2π (rad), the deposition rate with time of the deposition material deposited on the measurement point may be calculated by Equation 1 below.

[Equation 1]

J (r, t) = J (0, t) × H ⁴ / {F ² + r ² + H ^2- [2 × F × r × cos (2π × t / T)]} ²

According to this equation, it can be seen that as the distance from the substrate center, i.e., r becomes larger, the thickness (integral value integrated during deposition period T) becomes thinner.

Accordingly, the present inventors perform screening for a portion of the thick portion for a predetermined time so that the overall film thickness is formed equal to the substrate edge portion.

The inventors assume that the height H from the evaporation source to the substrate is 100 cm, the offset values F of the evaporation source are 0, 30 cm and 60 cm, respectively, and the radial distance r from the center of the substrate. The experiment was conducted by selecting a plurality of different measuring points.

In the following description, a data sheet is created by selecting seven measurement points, but the number of the measurement points is not limited, and as the number of measurement points is increased, more accurate screeners can be designed. .

The seven measurement points were r0 (r = 0), r1 (r = 10 cm), r2 (r = 20 cm), r3 (r = 30 cm), r4 (r = 40 cm) and r5 (r = 50 cm) and r6 (r = 60 cm).

2 is a data sheet calculated using Equation 1 when the offset value F is zero, in which the vertical axis represents the rotation angle rad of the substrate.

According to the data sheet of FIG. 2 described above, the sum of deposition rates according to respective rotation angles at each measurement point r0 to r6, that is, the integral value is the minimum sum at the measurement point r6 60 cm away from the substrate center. It can be seen that the value MIN; MIN # 34.6 is represented, and the maximum sum value MAX (MAX = 64) is shown at the substrate center r0.

Therefore, according to this data sheet, the uniformity (UF; UF = {(MAX-MIN) / (MAX) is calculated by dividing the difference between the maximum sum and the minimum sum by the sum of the maximum sum and the minimum sum and multiplying by 100. It can be seen that + MIN)} × 100) is 29.81%.

However, the rotation angle rad is increased from the point at which the rotation angle of each of the remaining measurement points r0 to r5 is π (rad) based on the measurement point r6 representing the minimum sum MIN. When the deposition rate is converted to zero in the decreasing direction and the summation value is adjusted to fall within a range that satisfies the set uniformity, the data sheet shown in FIG. 3 can be created.

According to the data sheet of FIG. 3, the uniformity UF is improved to approximately 2.35%.

Of course, in the data sheet of FIG. 3, the uniformity and the design shape of the screener may change little by little depending on the amount of conversion of the deposition rate values of the respective measuring points r0 to r5. It is preferable to suitably convert the deposition rate value within the range of% or less.

Then, the screener is designed in the same or similar shape as the region where the measurement rate is converted to zero in the above data sheet, and using a metal such as sus (SUS) or a ceramic such as alumina without outgassing in vacuum. The screener 10 shown in FIG. 4 is manufactured.

According to this method, the screener 10 of the shape which gradually decreases in width from the center of a board | substrate toward a board | substrate edge can be manufactured.

In addition, when the offset value F of the evaporation source is 0, the uniformity may be improved to about 2.35% by using the screener 10 of FIG.

5 is a data sheet calculated using Equation 1 above when the offset value F is 30 cm.

According to the data sheet of FIG. 5, the sum of the deposition rates according to the rotation angles at each measurement point r0 to r6, that is, the integral value is the minimum at the measurement point r6 60 cm away from the center of the substrate. It can be seen that the sum value MIN; MIN # 33.9 is represented, and the maximum sum value MAX MAX53.9 is represented at the substrate center r0.

Therefore, according to this data sheet, it can be seen that the uniformity UF is approximately 22.81%.

However, if the deposition rate of each deposition point is converted in the same manner as the data sheet creation method of FIG. 3 described above, the data sheet shown in FIG. 6 can be created.

According to the data sheet of FIG. 6, the screener 20 is formed in the same width by a predetermined distance from the center of the substrate toward the edge of the substrate, and is formed in a shape that gradually decreases in width. (UF) can be improved to 2.84%.

8 is a data sheet calculated using Equation 1 above when the offset value F is 60 cm.

According to the data sheet of FIG. 8 described above, the sum of the deposition rate according to each rotation angle at each measurement point r0 to r6, that is, the integral value is the minimum sum at the measurement point r6 60 cm away from the center of the substrate. It can be seen that the value MIN; MIN # 29.5 is shown, and the maximum sum value MAXMAX34.6 is represented at the measurement point r1 where the distance r from the center of the substrate is 10 cm.

Therefore, according to this data sheet, it can be seen that the uniformity UF is approximately 7.93%.

However, if the deposition rate of each deposition point is converted in the same manner as the data sheet creation method of Fig. 3 described above, the data sheet shown in Fig. 9 can be created.

According to the data sheet of FIG. 9, the screener 30 is formed in a shape in which the width gradually increases from the center of the substrate toward the substrate edge and then decreases. When the screener 30 having such a shape is used, the uniformity (UF) is reduced. Can be improved to 1.35%.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

As described above, the present invention can improve the film thickness uniformity to 3% or less by designing the screener by applying a constant design rule according to the offset value of the evaporation source.

Therefore, the luminance nonuniformity can be improved and stability can be ensured.

Claims (7)

Setting a height H from the evaporation source to the substrate and an offset value F of the evaporation source; Selecting a plurality of measurement points having different radial distances r from the center of the substrate; Calculating a deposition rate of a deposition material deposited at the measurement point while rotating the substrate by 2 pi (rad) to create a data sheet; Summing the deposition rates for each measurement point to calculate a summation value respectively; Based on the measurement point indicating the minimum summation value, the deposition rate is converted to zero in a direction in which the rotation angle rad increases and decreases from a point where the rotation angle of each of the remaining measurement points is π (rad). Adjusting the summation value such that the summation value of the remaining measurement points falls within a range satisfying the set uniformity; And Designing a screener with the same shape as the region converted to zero Screener design method comprising a. The method of claim 1, A method of designing a screener using the following Equation 1 in calculating a deposition rate of a deposition material deposited at the measurement point while rotating the substrate by 2π (rad) to prepare a data sheet. [Equation 1] (J (r, t) = J (0, t) × H ⁴ / {F ² + r ² + H ^2- [2 × F × r × cos (2π × t / T)]} ² In Equation 1, T represents a rotation period in which the substrate rotates once. The method of claim 2, And adjusting the maximum sum value so that the uniformity calculated using the adjusted maximum sum value and the minimum sum value is 3% or less. A screener made of a metal or ceramic material according to a shape designed by the screener design method according to any one of claims 1 to 3. The method of claim 4, wherein And the screener is formed in a gradually decreasing width from the substrate center toward the substrate edge. The method of claim 4, wherein And the screener is formed to a width that gradually increases from the center of the substrate toward the substrate edge and then decreases. The method of claim 4, wherein And the screener is formed in the same width from the center of the substrate toward the substrate edge and gradually decreases in width.

Images