WO2005091683A1

WO2005091683A1 - Substrate depositing method and organic material depositing apparatus

Info

Publication number: WO2005091683A1
Application number: PCT/KR2005/000269
Authority: WO
Inventors: Chang-Hun Hwang; Gun-Mook Lim; You-Tae Won; Sok-Won Noh; Kwang-Ho Kim; Taek-Sang Kang; Seung-Han Kim
Original assignee: Doosan Dnd Co., Ltd.
Priority date: 2004-03-22
Filing date: 2005-01-29
Publication date: 2005-09-29
Also published as: JP2005273014A; JP4178249B2; TWI274792B; TW200532051A

Abstract

The invention relates to an apparatus and method for depositing an organic material, and, more particularly, to an apparatus and method for depositing an organic material, designed to prevent a large size substrate conveyed into a chamber of the apparatus from sagging during a process of depositing an organic material. The apparatus comprises a chamber having an internal space shielded from the outside, an entrance provided at one side of the chamber to allow a substrate to be conveyed into or out of the chamber, and a gate for opening or closing the entrance, a substrate mounting platen provided at an upper portion of the chamber for applying tensile force to a substrate in order to prevent the substrate from sagging by fixing both ends of the substrate conveyed into the chamber via compressing force and moving one side of the substrate having both ends in a fixed state towards the outside, a rotational lifter coupled to the center of an upper surface of the substrate mounting platen for rotating, lifting or lowering the substrate mounting platen, and a heater and an organic material boat provided at a lower portion of the chamber for vaporizing the organic material and depositing it onto the substrate.

Description

Description SUBSTRATE DEPOSITING METHOD AND ORGANIC MATERIAL DEPOSITING APPARATUS Technical Field

[1] The present invention relates to an apparatus and method for depositing an organic material, and, more particularly, to an apparatus and method for depositing an organic material, designed to prevent a large size substrate conveyed into a chamber of the apparatus from sagging during a process of depositing an organic material.

[2] Background Art

[3] Recently, according to the rapid development of information communication technologies and the expansion of market demand, flat panel displays have moved to the forefront of display technology. As representative flat panel displays, there are liquid crystal displays, plasma display panels, organic light emitting diodes, and the like.

[4] Among the flat panel displays, the organic light emitting diode has been highlighted as a next generation display due to its advantages, such as rapid response time, lower power consumption in comparison to conventional liquid crystal displays, lightness, ultra slim thickness due the absence of a backlight, high brightness, and the like.

[5] The organic light emitting diode works on the principle of electroluminescence wherein, with the construction in which a cathode film, an organic thin film, and an anode film are coated on a substrate, when a voltage is applied to the cathode and the anode, an appropriate energy difference is created between both sides of the organic thin film. That is, electrons and holes injected through the cathode and the anode, respectively, recombine in the organic thin film, so that a remaining excited energy after the recombination between the electrons and holes gives off light. At this time, since the wavelength of the light generated from the organic thin film can be controlled according to the amount of dopant of the organic material, it is possible to realize full color. With regard to this, a glass substrate used for manufacturing the display tends to increase in size due to improvement of productivity and an increase in size of the display.

[6] As for a detailed construction of the organic light emitting diode, it comprises the anode, a hole injection layer, a hole transfer layer, a light emitting layer, an electron transfer layer, an electron injection layer, and the cathode sequentially stacked on the substrate in this order. Here, as for the anode, indium tin oxide (ITO) having a low in- plane resistance and good transmittance is mainly used. The organic thin film consists of multiple layers, such as the hole injection layer, the hole transfer layer, the light emitting layer, the electron transfer layer, and the electron injection layer, in which an organic material for the light emitting layer includes Alq , TPD, PBD, m-MTDATA, TCTA, and the like. As for the cathode, a LiF-Al metal film is used. Additionally, since the organic thin film exhibits extremely weak resistance to moisture and oxygen, an encapsulating film for encapsulating the diode is formed on the uppermost portion of the diode in order to increase the lifetime of the diode.

[7] However, in spite of various advantages as described above, since an apparatus for producing a large area organic light emitting diode is not securely standardized, currently, the organic light emitting diode is not securely established as the next generation display substituted with the conventional flat panel displays. That is, considering that an apparatus for producing a large area panel has been developed and standardized according to the rapid increase in size of the liquid crystal display or the plasma display, there is a strong need for development of an apparatus for producing a large area organic light emitting diode, which can allow the organic light emitting diode to be securely substituted as the next generation display.

[8] Meanwhile, when manufacturing the flat panel display, such as the organic light emitting display, the display is formed on a glass substrate under the consideration of the characteristics of the display, and during a deposition process, the glass substrate must be held by a holding device, such as glass chucks, such that a depositing surface faces downwardly in a vacuum state.

[9] One of the widely used glass chucks is a clipping chuck that physically supports four sides of the glass substrate, and the others are a vacuum chuck using a difference in atmospheric pressure, and an electrostatic chuck using an electric field and electrostatic induction.

[10] The vacuum chuck employs the difference in atmospheric pressure in such a manner that, with an adsorption plate contacting a rear side of the flat glass substrate, it holds the glass substrate through intake of air from the adsorption plate. Accordingly, there are problems in that the vacuum chuck cannot be used in the deposition process because the deposition process is mainly carried out in a vacuum state, and that it has a complicated construction.

[11] That is, for the flat panel display, since foreign matters, such as dust, water vapor, oxygen, etc., act as main factors increasing product defect ratio, it is necessary to perform the operation in a vacuum state, and in view of this circumstance, the vacuum chuck cannot be applied to the vacuum apparatus.

[12] Meanwhile, the electrostatic chuck holds the flat substrate by use of electrostatic force generated between the electrostatic chuck and the flat substrate by electrifying the flat substrate with the electric field generated when electric current is applied to the rear side of the flat substrate, and can be used in the vacuum state. However, the electrostatic chuck has several problems as described below.

[13] In the case of holding a flat glass substrate having a large area, the electrostatic chuck requires a large electric field, thereby increasing power consumption. Additionally, in order to allow electric current to be continuously supplied during various types of deposition processes, not only does the electrostatic chuck require complex machinery, but also the electric field generated on the substrate by the electric current influences the materials deposited on the flat glass substrate, that is, deposited chemicals, thereby lowering performance.

[14] When clipping the glass substrate, the center of the substrate sags due to the dead weight. At this time, if the thickness of the glass substrate is 370 X 470 mm, the substrate sags by approximately 1 mm, and if the thickness of the glass substrate is 600 X 720 mm, the substrate sags by approximately 5 mm. Additionally, the vacuum chuck cannot be used for the deposition process carried out in the vacuum state, and in the case of large area glass substrate, the electrostatic chuck requires a very strong electric field, and has a difficulty in management of electric wires upon conveying the substrate.

[15] A conventional apparatus for depositing the organic material comprises a vacuum chamber in which the deposition process is carried out, a substrate mounting platen provided at an upper portion of the chamber for mounting a substrate, a magnet holder provided above the substrate mounted on the substrate mounting platen, a mask holder provided below the substrate mounted on the substrate mounting platen, a heater provided at a lower portion of the chamber for vaporizing an organic material and depositing it onto the substrate, and an organic material boat provided at the lower portion of the chamber.

[16] Here, the vacuum chamber is evacuated to below 10 Torr by use of a vacuum pump after placing a presumed appropriate amount of the organic material to be deposited onto the substrate on the organic material boat. At this time, the organic material boat generally consists of molybdenum. Then, power is applied to the heater, and the temperature of the heater is increased to the melting point of the organic material through precise control of the temperature using a temperature controller (not shown) until the organic material is vaporized. At this time, as the organic material starts to evaporate from the organic material boat, a previously installed shutter is opened, allowing the vaporized material to be deposited onto the substrate. Here, the shutter acts to prevent impurities remaining immediately before evaporation of the organic material on the organic material boat from being deposited on the substrate.

[17] The conventional apparatus for depositing the organic material has a problem in that the organic material cannot be uniformly deposited on the substrate since the large area substrate sags due to the dead weight during mounting the substrate on the substrate mounting platen.

[18] Disclosure of Invention Technical Problem

[19] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus and method for depositing an organic material, designed to impart a tensile force to a substrate by stretching one side of the substrate with both sides of the substrate fixed by a compressing holder to prevent the center of the substrate from being lowered due to the dead weight during a deposition process for the substrate, thereby preventing the substrate from sagging.

[20] Technical Solution

[21] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of an apparatus for depositing an organic material, comprising: a chamber having an internal space shielded from the outside, an entrance provided at one side of the chamber to allow a substrate to be conveyed into or out of the chamber, and a gate for opening or closing the entrance; a substrate mounting platen provided at an upper portion of the chamber for applying tensile force to a substrate in order to prevent the substrate from sagging by fixing both ends of the substrate conveyed into the chamber via compressing force and moving one side of the substrate having both ends in a fixed state towards the outside; a rotational lifter coupled to a center of an upper surface of the substrate mounting platen for rotating, lifting or lowering the substrate mounting platen; and a heater and an organic material boat provided at a lower portion of the chamber for vaporizing the organic material and depositing it onto the substrate. Accordingly, the substrate mounting platen for mounting the substrate conveyed into the chamber for deposition of the organic material is provided, thereby preventing the large area substrate from sagging.

[22] The substrate mounting platen may comprises: a substrate seating holder provided inside the substrate mounting platen, and adapted to allow one side of the substrate seating holder to be separated from the other side, the substrate seating holder having a plate shape penetrated at the center thereof such that four sides of the substrate can be seated on a through portion defined in the substrate seating holder; a compressing holder provided above the substrate mounting platen so as to be raised or lowered, and adapted to compress both sides of the upper surface of the substrate when being lowered, and to allow one side of the compressing holder at one side of the substrate to be separated from the other side co-linear with the one side of the substrate seating holder, the compressing holder having a plate shape penetrated at the center thereof; a first driving member provided downwardly above either side of an upper surface of the compressing holder for compressing or decompressing an associated side of the upper surface of the substrate according to supply or discharge of air; and a second driving member located orthogonal to the first driving member and fixed to the one side of the compressing holder for linearly reciprocating the substrate seating holder and the compressing holder, each of which is in a state that the one side thereof is separated from the other side, according to supply or discharge of air, such that the one side of the substrate with both ends thereof fixed by the compressing holder is stretched, thereby preventing the substrate from sagging, through linear reciprocation. Accordingly, when the compressing holder compresses and fixes the sides of the upper surface of the substrate seated on the substrate seating holder, the first and second driving members applies compressing force and tensile force to the substrate, respectively, in such a manner that the second driving member acts to apply the tensile force to the substrate by moving one side of the substrate toward the outside while the first driving member acts to fix both sides of the substrate, thereby preventing the substrate from sagging.

[23] Each of the first and second driving members may comprise: a plate-shaped base; fixing plates positioned upright at both sides of an upper surface of the base; a moving plate located between the fixing plates so as to reciprocate therebetween and having a shaft formed at the center of a front face of the moving plate so as to penetrate the fixing plate in front of the moving plate; a bellows provided between the moving plate and the fixing plate at the rear of the moving plate with both ends of the bellows fixed to the moving plate and the fixing plate, respectively, and adapted to linearly move the shaft of the moving plate forward according to a volume increase occurring when the bellows is filled with air; an air injection nozzle for injecting air into the bellows from the outside; and a spring provided around the shaft between the moving plate and the fixing plate so as to impart restoration force to the bellows during shrinkage of the bellows upon discharge of the air from the bellows. Accordingly, the bellows can impart forward force or backward force according to whether the bellows is filled with air or not.

[24] The apparatus for depositing the organic material may further comprise: a substrate fixing part for supplying the compressing force; a tensile force applying part; and a controller for controlling the compressing force supplied from the substrate fixing part and the tensile force supplied from the tensile force applying part, so that correction of the compressing force and the tensile force can be performed according to a result of inspection for a sagging amount of the substrate by the compressing force and the tensile force.

[25] The substrate fixing part may comprise: an elongated lower plate longer than a fixed portion of the substrate; a plate-shaped fixing holder located above the lower plate and adapted to allow the substrate to be seated on an upper surface thereof, the fixing holder having the same shape as that of the lower plate; a position fixing plate provided at one side of the fixing holder while being extended longitudinally, the position fixing plate having an L-shaped cross-section; a driving member fixing plate spaced from the position fixing plate while being located at the center above the fixing plate; a compressing holder adapted to be raised or lowered in a space between the driving member fixing plate and the fixing holder to compress or decompress the upper surface of the substrate seated on the fixing holder, the compressing holder having a plate shape extended longitudinally; and a vertical driving member provided at the center of an upper surface of the driving member fixing plate to raise or lower the compressing holder so as to apply the compressing force to the substrate, the vertical driving member having a moving shaft fixed at its leading end to the compressing holder. The vertical driving member is provided at an upper portion of the substrate fixing part so as to raise or lower the compressing holder, thereby allowing both ends of the substrate to be fixed via the simple structure of the vertical driving member.

[26] The vertical driving member may be provided with a first pressure gauge on the moving shaft for measuring and outputting a load in the vertical direction.

[27] The first pressuring gauge may be at least one load cell.

[28] The tensile force applying part may comprise a stationary lateral plate fixed to the lower plate and an outer wall of the fixing holder of the substrate fixing part; a driving member fixing lateral plate spaced outwardly from the stationary lateral plate while positioned upright in a fixed state at the edge of one side of the base; and a horizontal driving member equipped to an outer wall of the driving member fixing lateral plate to move the movable substrate fixing part in the horizontal direction so as to apply the tensile force to the substrate, the horizontal driving member having a moving shaft fixed at its leading end to the movable substrate fixing part. The horizontal driving member is provided to the outer wall of one of the substrate fixing parts such that it supplies the tensile force by moving one end of the substrate outwardly while both ends of the substrate are fixed in position, thereby preventing the substrate from sagging.

[29] The at least one load cell may be a plurality of load cells, so that the tensile force and the compressing force can be more accurately measured.

[30] The vertical driving member and the horizontal driving member may apply different compressing forces and tensile forces to the substrate according to a thickness of the substrate, respectively, so that an optimal compressing force and tensile force can be applied to the substrate irrespective of variation in the condition of the substrate including the thickness of the substrate.

[31] The controller may be provided with a display electrically connected to the controller to output a result of detection by the first pressure gauge and a second pressure gauge in numerical form, thereby allowing an operator to recognize the compressing force and the tensile force with the number.

[32] Brief Description of the Drawings

[33] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: [34] Fig. 1 is a side elevation illustrating the overall construction of an apparatus for depositing an organic material according to a first embodiment of the present invention; [35] Fig. 2 is a plan view illustrating a substrate aligning memebr of the apparatus of the present invention; [36] Figs. 3a and 3b are a plan view and a side elevation illustrating first and second driving members of the apparatus of the invention; [37] Fig. 4 is a perspective view illustrating a substrate mounting platen of an apparatus for depositing an organic material according to a second embodiment of the present invention; [38] Fig. 5 is a cross-sectional view of Fig. 4;

[39] Figs. 6a to 6c are schematic views illustrating a process of fixing a substrate to the substrate mounting platen of the apparatus according to the second embodiment; [40] Figs. 7a and 7b are a plan view illustrating the substrate mounted on the substrate mounting platen of the apparatus according to the second embodiment, and a graph showing the relationship between sagging amount and clamping length of the substrate while both sides thereof are hold on fixing holders of the the substrate mounting platen; [41] Figs. 8a and 8b are a plan view illustrating the substrate mounted on the substrate mounting platen of the apparatus according to the second embodiment, and a graph showing the relationship between sagging amount and clamping length of the substrate while both sides thereof are hold on fixing holders of the substrate mounting platen; [42] Fig. 9 is a block diagram of a method for depositing an organic material according to the present invention; [43] Figs. 10a to 10c are schematic views illustrating a process for fixing a substrate to a substrate mounting platen of an apparatus for depositing an organic material according to a third embodiment of the present invention;

[44] Fig. 11 is a partially schematic view illustrating substrate contact holders of the substrate mounting platen shown in Figs. 10a to 10c; and

[45] Figs. 12a and 12b are conceptual views illustrating a fixing method in which Fig. 12a shows the substrate stretched vertically and horizontally, and Fig, 12b shows the substrate stretched diagonally.

[46] Best Mode for Carrying Out the Invention

[47] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[48] Embodiment 1

[49] Referring to Fig. 1, an apparatus for depositing an organic material according to a first embodiment comprises: a chamber 110 in which a substrate S is loaded and subjected to a deposition process; a first driving member 220 provided inside the chamber 100 to fix sides of the substrate S; a second driving member 240' located orthogonal to the first driving member 220 to supply tensile force to the substrate S by use of pneumatic pressure in order to prevent the substrate S from sagging; and a rotational lifter 300 equipped to the top surface of the chamber 110 to rotate the substrate S such that the organic material can be uniformly distributed over the substrate S in the chamber during evaporation of the organic material.

[50] Here, the chamber 110 has an internal space shielded from the outside thereof, an entrance (not shown) formed at one side of the chamber 110 for allowing the substrate S to be conveyed into or from the chamber 110, and a gate (not shown) for opening and closing the entrance. The chamber 110 is adapted to allow the substrate S to be deposited with the organic material therein.

[51] Further, vacuum pumps P are equipped to edges of the bottom surface of the chamber 110, and act to lower the internal pressure of the chamber 110. That is, in order to deposit a pure organic material on the surface of the substrate S, impurities must be eliminated from the interior of the chamber 110 when depositing the organic material on the substrate S. With regard to this, the vacuum pumps P act to eliminate the impurities by removing air from the deposition chamber 110.

[52] The chamber 110 is provided with a plate 202, and a substrate mounting platen 200 positioned a predetermined distance below the plate 202, and a housing 120 positioned below the substrate mounting platen 200 within an upper portion of the chamber 110. The substrate mounting platen 200 comprises a substrate seating holder 210, a compressing holder 208, the first driving member 220, and the second driving member 240.

[53] The plate 202 is provided at one side with a fixed lateral plate 204, and at the other side with a movable lateral plate 206 which can move horizontally. The substrate seating holder 210 is provided in a transverse direction to each lower end of the fixed lateral plate 204 and the movable lateral plate 206, and the compressing holder 208 is provided in parallel to the substrate seating holder 210 so as to be raised or lowered.

[54] The housing 120 is opened at a lower portion, and has a C-shaped cross-section. The housing 120 comprises a mask holder 122 horizontally provided to either lower end of the housing 120, a pair of plate-shaped magnet holders 124 provided at an upper portion of the housing 120 for imparting magnetic force, and a mask 126 seated on the mask holder 122.

[55] The magnet holders 124 apply magnetic force to the mask 126, and force the mask 126 to be in intimate contact with a lower surface of the substrate S, that is, a patterned surface of the substrate S.

[56] The substrate seating holder 210 has a plate shape penetrated at the center thereof such that four sides of the substrate S can be seated on a through portion defined in the substrate seating holder 210, and is adapted to allow one side of the substrate seating holder 210 to be separated from the other.

[57] The compressing holder 208 has a shape corresponding to that of the substrate seating holder 210, and is provided above the substrate seating holder 210 so as to be raised or lowered by the first driving member 220. The compressing holder 208 fixes the substrate S by compressing both sides of the upper surface of the substrate S when being lowered, and also has a plate shape penetrated at the center thereof. As with substrate seating holder 210, one side of the compressing holder 208 can be separated from the other and positioned co-linear with the one side of the substrate seating holder 210.

[58] That is, the compressing holder 208 provided above the substrate seating holder 210 so as to be raised or lowered by the first driving member 220 acts to compress both sides of the upper surface of the substrate S seated on the substrate seating holder 210.

[59] As shown in Fig. 2, the substrate seating holder 210 has the plate shape penetrated at the center thereof, and is formed with a step at a border between the upper surface of the substrate and side surfaces of the through portion, thereby allowing the substrate to be easily seated on the step.

[60] Additionally, the substrate seating holder 210 is provided with four positioning cylinders 130, and four aligning cylinders 132 opposite to the positioning cylinders 130 at four sides of the substrate S so as to align the substrate S seated thereon.

[61] The positioning cylinders 130 are driven by pneumatic pressure, and provide reference points for the substrate S when it is seated on the substrate seating holder 210 for deposition.

[62] The aligning cylinders 130 are driven by the pneumatic pressure, and move the substrate S to the reference points of the substrate S, when aligning the substrate S.

[63] Here, the four positioning cylinders 130 are located at two adjoining sides of the substrate S, and define the reference points for the substrate S. Meanwhile, the four aligning cylinders 130 are located at the other two adjoining sides of the substrate S so as to be opposite to the four positioning cylinders 130, and align the substrate S by applying compressing force from the sides of the substrate S to the positioning cylinders 130, respectively.

[64] The first driving member 220 acting to raise or lower the compressing holder 208 is reciprocated by a transmitting member 212 provided between the first driving member 220 and the compressing holder 208. The transmitting member 212 has a bar shape, and is folded in opposite directions at both ends thereof.

[65] The movable lateral plate 206 moves freely outward by means of a guide at one side of an upper surface of the plate 202, and at this time, linear reciprocation of the movable lateral plate 206 is controlled by the second driving member 240 equipped in the transverse direction.

[66] Referring to Figs. 3a and 3b, the first driving member 220 comprises a plate- shaped base 222; a pair of fixing plates 224 positioned upright at both sides of the upper surface of the base 222; a moving plate 226 located between the fixing plates 224 so as to reciprocate therebetween and having a shaft 228 formed at the center of a front face of the moving plate 226 so as to protrude to the outside through the fixing plate 224 in front of the moving plate 226; a bellows 232 provided between the moving plate 226 and the fixing plate 224 at the rear of the moving plate 226 with both ends of the bellows 232 fixed to the moving plate 226 and the fixing plate 224, respectively, and adapted to linearly move the shaft 228 forward according to a volume increase occurring when the bellows is filled with air supplied from a compressor (not shown) provided at the outside of the chamber; an air injection nozzle 234 for injecting air introduced from the outside into the bellows 232; and a spring 236 provided around the shaft 224 between the moving plate 226 in a moving state and the fixing plate 224 to the rear of the moving plate 226 so as to impart restoration force to the bellows 232 during shrinkage of the bellows 232 due to discharge of the air from the bellows 232. Here, a buffering force control plate 238 for compressing or releasing the spring 236 is fixed onto the shaft 228 so as to control buffering force of the spring 236.

[67] Here, the second driving member 240' has the same shape and function as those of the first driving member 220, and thus a detailed description will be omitted herein. The difference lies in the fact that the first driving member 220 is fixed longitudinally to the fixed lateral plate 204 and the movable lateral plate 206, and acts to raise or lower the compressing holder 208, whereas the second driving member 240' is equipped adjacent to the movable lateral plate 206 of the plate 202 in a state of being orthogonal to the first driving member 220, and acts to move the movable lateral plate 206 outward or restore it to an original position by use of pneumatic pressure in a state of being fixed to the upper end of the movable lateral plate 206.

[68] Meanwhile, reference numerals 242, 244, 246, 248, 250, 252, 254, 256 and 258 indicate the base, the fixing plate, the moving plate, the shaft, a clamp, the bellows, the air injection nozzle, the spring, and the buffering force control plate, respectively.

[69] As shown in Fig. 1, the rotational lifter 300 is equipped on the upper surface of the chamber 110 to rotate the substrate S such that the organic material can be uniformly distributed over the substrate S within the chamber 110 during deposition of the organic material. The rotational lifter 300 comprises a first hollow shaft 306 extended downwardly from the interior of a rotational lifter housing 304 to the upper surface of the substrate mounting platen 200 within the chamber 110, a second hollow shaft 308 extended from above the first hollow shaft 306 to the upper surface of the magnet holder 124 within the first hollow shaft 306, and an air injector 302 equipped at an upper portion of the rotational lifter 300 to supply the pneumatic pressure from the compressor to the first and second driving members 220 and 240' the positioning cylinders 130, and the aligning cylinders 132.

[70] The mask holder 122 of the substrate mounting platen 200 provided below the lower end of the first hollow shaft 330 raises or lowers the mask by driving a servo motor (not shown), and the magnet holder provided to the lower end of the second hollow shaft 340 raises or lowers the substrate S by means of a cylinder (not shown).

[71] The apparatus may further comprise an additional rotating device (not shown) to rotate the substrate mounting platen 200 having the substrate S mounted thereon.

[72] The apparatus further comprises a heater 140, and an organic material boat 142 provided within a lower portion of the chamber 110 for vaporizing the organic material and depositing it onto the substrate S.

[73] Operation of the apparatus for depositing an organic material according to the present embodiment will be described hereinafter with reference to Figs. 1 to 3c. First, a substrate S is seated on the substrate seating holder 210 of the substrate mounting platen 200 through the entrance formed at one side of the chamber 110 by use of a conveying means (not shown) provided at the outside of the chamber 110.

[74] After closing the entrance of the chamber 110 with the gate, air within the chamber 110 is discharged to the outside by means of a plurality of chambers P equipped to edges of the bottom surface of the chamber 110.

[75] Then, air is injected from the compressor provided at the outside of the chamber into the bellows 232 of the first driving member 220 equipped to the fixed lateral plate 204 and the movable lateral plate 206 such that the compressing holder 208 can be lowered in order to fix the substrate S seated on the substrate seating holder 210. When the bellows 232 has an increased volume due to the air supplied from the compressor, the shaft 228 of the moving plate 226 is moved forward, and then a clamp 230 provided to the distal end of the shaft 228 forces the transmitting member 212 to be lowered, so that the compressing holder 208 provided to the transmitting member 230 is lowered.

[76] As the compressing holder 208 is lowered, it fixes the substrate S by compressing both sides of the upper surface of the substrate S, and when the substrate S is firmly fixed, air is injected into the second driving member 240 acting to move the movable lateral plate 206, such that the shaft 248 of the second driving member 240 is moved forwardly, and forces the movable lateral plate 206 to be moved horizontally towards the outside.

[77] Here, the substrate S interposed between the substrate seating holder 210 and the compressing holder 208 is firmly fixed, and at this time, the second driving member 240 provided to the movable lateral plate 206 is operated to force the movable lateral plate 206 to move outward and to stretch one side of the substrate S, thereby allowing the substrate S to be located horizontally while preventing the substrate S from sagging due to the dead weight.

[78] Then, power is applied to the heater 140 provided at the bottom surface of the chamber 110, and the temperature of the heater is increased to the melting point of the organic material through precise control of the temperature using a temperature controller (not shown) until the organic material is vaporized. At this time, as the organic material on the organic material boat 142 starts to evaporate, a previously installed shutter (not shown) is opened, allowing the vaporized material to be deposited onto the substrate S. Here, the shutter acts to prevent impurities remaining immediately before evaporation of the organic material on the organic material boat 142 from being deposited on the substrate S.

[79] At this time, the substrate S is rotated by means of the rotational lifter 300 such that the organic material can be uniformly distributed over the substrate S in the chamber 110 during deposition of the organic material. After completing the deposition for the substrate S, air within the second driving member 240 is discharged to the outside. Accordingly, the movable lateral plate 206 returns to its original position due to the restoration force of the spring 256 provided around the shaft 248, and releases the tensile force applied to the substrate S. Finally, the compressing holder 208 is raised by means of the first driving member 220 from which the air is discharged, and the substrate S is conveyed from the chamber 110 by the conveying means. [80] According to the present embodiment, during the deposition process conducted within the chamber 110 of the apparatus 100, the one side of the substrate S is stretched horizontally while both ends are fixed by the compressing holder 208 so that the substrate S having a large area is prevented from sagging due to the dead weight upon mounting the substrate S.

[81]

[82] Embodiment 2

[83] Although not shown in the drawings, an apparatus for depositing an organic material according to a second embodiment of the invention comprises a chamber (not shown) in which a substrate S having a large area is loaded and subjected to a deposition process; a substrate mounting platen 400 provided at an upper portion of the chamber for preventing the substrate S from sagging in a state that both ends of the substrate S are fixed; and a rotational lifter (not shown) coupled to the top surface of the chamber for rotating the substrate S such that the organic material can be uniformly distributed over the substrate S in the chamber during evaporation of the organic material.

[84] The apparatus for depositing an organic material according to the second embodiment has construction and function similar to those of the first embodiment except for some components, such as the substrate mounting platen 400 and the like, and thus a detailed description of the similar construction of the apparatus according to the second embodiment will be omitted.

[85] The apparatus for depositing the organic material further comprises a controller (not shown) for controlling compressing force and tensile force when preventing the substrate S from sagging by application of the compressing force and tensile force to both ends of the substrate S mounted on the substrate mounting platen 400, and a display (not shown) electrically connected to the controller for outputting a numerical result of detection for the compressing force and tensile force.

[86] The apparatus further comprises a heater (not shown), and an organic material boat (not shown) provided within a lower portion of the chamber for vaporizing the organic material and depositing it onto the substrate S.

[87] Referring to Figs. 4 and 5, the substrate mounting platen 400 comprises: a plate- shaped base 540; a pair of substrate fixing parts 410 and 510 provided to opposite sides of the base 540, respectively; a pair of horizontal moving guides 542 equipped longitudinally on an upper surface of the base 540 such that the substrate fixing parts 410 and 510 are located at both ends of an upper surface of the horizontal moving guides 542; and a tensile force applying part 550 provided orthogonal to an outer surface of one of the substrate fixing parts, which can be moved, for applying tensile force to the substrate by moving the substrate fixing part outwardly. [88] The apparatus further comprises a driving member fixing lateral plate 544, and a lateral plate 536 positioned upright at opposite ends of the base 540, respectively.

[89] The substrate fixing parts 410 and 510 move in the horizontal direction on the horizontal moving guide 542 such that a distance between the substrate fixing parts 410 and 510 can be adjusted according to the size of the substrate S.

[90] Both substrate fixing parts 410 and 510 have the same shape and function except that the substrate fixing part 410 is a stationary type provided at one side of the base 540, but the substrate fixing part 510 is a movable type provided at the other side of the base 540. Here, both the stationary and movable substrate fixing parts 410 and 510 can be moved, so that a distance between the substrate fixing parts 410 and 510 can be adjusted according to the size of the substrate S having the large area, thereby allowing deposition on various substrates having different areas.

[91] The substrate fixing parts 410 and 510 comprise a stationary member 412 fixed at one side of the horizontal moving guides 542, and a movable member 512 provided at the other side so as to be horizontally movable, respectively, in a state wherein both members 412 and 512 are in contact with the pair of horizontal moving guides 542 provided longitudinally on the upper surface of the base 540. Each substrate fixing part 410 or 510 further comprises longitudinally extended lower plate 414 or 514 equipped on an upper surface of the stationary member 412 or the movable member 512; a plate- shaped fixing holder 416 or 516 located above the lower plate 414 or 514 with upright plates interposed between the fixing holder 416 or 516 and the lower plate 414 or 514 in order to ensure separation therebetween, and adapted to allow the substrate S to be seated on an upper surface thereof, in which each fixing holder 416 or 516 has the same shape as that of each lower plate 414 or 514; a position fixing plate 418 or 518 provided at one side of the fixing holder 416 or 516 and extended longitudinally in which the position fixing plate 418 or 518 has an L-shaped cross-section; a driving member fixing plate 420 or 520 spaced from the position fixing plate 418 or 518 and located at the center above the fixing plate 418 or 518; a compressing holder 426 or 526 adapted to be raised or lowered in a space between the driving member fixing plate 420 or 520 and the fixing holder 416 or 516 in order to compress the upper surface of the substrate S seated on the fixing holders 416 and 516 in which the compressing holder 420 or 520 has a plate shape extended longitudinally; and a vertical driving member 428 or 528 provided at the center of an upper surface of the driving member fixing plate 420 or 520 to raise or lower the compressing holder 420 or 520 so as to apply the compressing force to the substrate S.

[92] A compressing part 422 or 522 consists of the compressing holder 426 or 526, and a moving plate 424 or 524 provided above the compressing holder 426 or 526, and is provided with a plurality of vertical shaft in order to maintain separation between the compressing holder 426 or 526 and the moving plate 424 or 524.

[93] The compressing part 422 or 522 consists of the compressing holder 426 or 526, and the moving plate 424 or 524.

[94] Here, the vertical driving member 428 or 528 is a hydraulic or pneumatic cylinder, and compresses the substrate S using liquid or air supplied from the outside.

[95] The vertical driving member 428 or 528 is provided with a first pressure gauge L on a moving shaft thereof. The first pressuring gauge L may be at least one load cell, which is subjected to deformation, such as extension or depression, upon application of load thereto. The degree of deformation is detected as an electric signal, and is then transformed into a digital signal by a deformation detector so that compressing force is output as a numerical result on the display of the controller.

[96] Additionally, a connecting plate 430 or 530 is interposed between the first pressure gauge L of the vertical driving member 428 or 528 and the compressing holder 426 or 526.

[97] That is, when the vertical driving member 428 or 528 is lowered, and compresses the substrate S, the compressing force, that is, the load, against the substrate S is imparted to the load cell, and is then transformed from the electric signal into the digital signal, thereby allowing the compressing force to be output as the numerical form.

[98] The tensile force applying part 550 is positioned upright. The tensile force applying part 550 comprises: the lower plate 514 of the movable substrate fixing part 510; a stationary lateral plate 552 fixed to an outer wall of the fixing holder 516 and positioned upright; a driving member fixing lateral plate 544 spaced from the stationary lateral plate 552 and provided at one side of the base 540; and a horizontal driving member 554 equipped to an outer wall of the driving member fixing lateral plate 544 for moving the movable substrate fixing part 510 in the horizontal direction.

[99] A horizontal shaft is interposed between the stationary lateral plate 552 and the driving member fixing lateral plate 544 in order to maintain separation therebetween.

[100] Here, the horizontal driving member 554 is a hydraulic or pneumatic cylinder, and compresses the substrate S by moving the movable substrate fixing part 510 outwardly using liquid or air supplied from the outside.

[101] Additionally, the horizontal driving member 554 is provided with a second pressure gauge L on the moving shaft. The second pressuring gauge L may be a load cell, which is subjected to a deformation, such as extension or depression, upon application of load thereto. The degree of deformation is detected as an electric signal, and is then transformed into a digital signal by a deformation detector so that compressing force is output in numerical form on the display of the controller.

[102] That is, as the moving shaft of the horizontal driving member 554 is moved outwardly in the horizontal direction, the one side of the substrate S is stretched while both sides of the substrate are fixed, and at this time, the tensile force, that is, the tensile load, against the substrate S is imparted to the load cell, and is then transformed from the electric signal into the digital signal, thereby allowing the tensile force to be output in the numerical form.

[103] Here, although the first and second pressure gauges L and L can consist of a single load cell, respectively, it is desirable that the first and second pressure gauges L and L consist of a plurality of load cells, respectively, in order to uniformly and accurately measure the load.

[104] Additionally, the vertical driving member 428 or 528, and the horizontal driving member 554 may apply the compressing force and the tensile force differently to the substrate S according to the thickness of the substrate S.

[105] Accordingly, after the compressing force and the tensile force applied to the substrate S are measured by use of the first and second pressure gauges L and L , the measurement is processed into data of the compressing force and the tensile force, and is then used in a feed back loop, thereby allowing the deposition process to be automated for mass production.

[106] Sagging of the substrate S can be divided into three steps, as shown in Figs. 6a to 6c, during a process of mounting the substrate S onto the substrate mounting platen 200. In the first step, since the compressing holders 426 and 526 do not compress the fixing holders 416 and 516, the substrate S is seated on the fixing holders 416 and 516 with no load applied to the substrate S, and at this time, a sagging amount of the substrate S due to the dead weight of the substrate S indicated by reference symbol "a" in Fig. 6a is the maximum value.

[107] In the second step, as shown in Fig. 6b, with the substrate S seated on the fixing holders 416 and 516, the compressing holders 426 and the 526 located above the fixing holders 416 and 516 are lowered, and apply compressing force to both ends of the substrate S. In this state, with both ends fixed by the compressing holders 426 and 526, the substrate has a sagging amount indicated by reference symbol "b", which is smaller than the sagging amount a of the substrate S in a freely seated state, since both ends of the substrate S are fixed by the compressing holders 426 and 526 on the fixing holders 416 and 516 even with sagging at the center of the substrate S due to the dead weight of the substrate S.

[108] In the third step, as shown in Fig. 6c, with the substrate S fixed by the compressing holders 426 and 526 on the fixing holders 416 and 516, the fixing holder 516 and the compressing holder 526 located at one side of the substrate S are moved outwardly, and then apply the tensile force to the substrate S, thereby preventing the substrate S from sagging. That is, as one side of the substrate S is stretched by applying the tensile force to the substrate S with both ends of the substrate S fixed by the compressing holders 426 and 526 on the fixing holders 416 and 516, sagging of the substrate S due to the dead weight of the substrate S does not occur.

[109] Figs. 7a and 7b are a plan view illustrating the substrate S with both longer sides of the substrate S fixed by the compressing holders 426 and 526 on the fixing holders 416 and 516, and a graph showing the relationship between sagging amount and clamping length of the substrate S when the compressing force and tensile force are concurrently applied to the substrate, respectively. As shown in Fig. 7b, it can be appreciated that the sagging amount of the substrate S is decreased as the clamping length of the compressing holders 426 and 526 for the substrate S is increased. In Fig. 7b, variation in sagging amount of the substrate S freely seated on the fixing holders 416 and 516 is indicated by a solid line, variation in sagging amount of the substrate S with both sides fixed by the compressing holders 426 and 526 according to the clamping length of the compressing holders 426 and 526 is indicated by a dotted line, and variation in sagging amount of the substrate S, one side of which is stretched by moving the fixing holders 416 and 516 and the compressing holders 426 and 526 outwardly, with both ends thereof fixed by the compressing holders 426 and 526 on the fixing holders 416 and 516, according to the clamping length of the compressing holders 426 and 526 is indicated by a broken line.

[110] According to the graph shown in Fig. 7b, it can be appreciated that the sagging amount of the substrate S is minimal when the tensile force is applied to one side of the substrate S with both ends fixed by compressing holders 426 and 526 on the fixing holders 416 and 516.

[Ill] Additionally, it can be appreciated that as the clamping length for the substrate S is increased, the sagging amount of the substrate S is decreased.

[112] Figs. 8a and 8b are a plan view illustrating the substrate S with both shorter sides of the substrate S fixed by the compressing holders 426 and 526 on the fixing holders 416 and 516, and a graph showing the relationship between sagging amount and clamping length of the substrate S when the compressing force and tensile force are concurrently applied to the substrate, respectively. As is shown in Fig. 8b, it can be appreciated that the sagging amount of the substrate S is decreased as the clamping length of the compressing holders 426 and 526 for the substrate S is increased. In Fig. 8b, variation in sagging amount of the substrate S freely seated on the fixing holders 416 and 516 is indicated by a dash-dot line, variation in sagging amount of the substrate S with both sides fixed by the compressing holders 426 and 526 according to the clamping length of the compressing holders 426 and 526 is indicated by a solid line, and variation in sagging amount of the substrate S, one side of which is stretched by moving the fixing holders 416 and 516 and the compressing holders 426 and 526 outwardly, with both ends thereof fixed by the compressing holders 426 and 526 on the fixing holders 416 and 516, according to the clamping length of the compressing holders 426 and 526 is indicated by a dash double-dot line.

[113] According to the graph shown in Fig. 8b, it can be appreciated that the sagging amount of the substrate S is minimal when the tensile force is applied to one side of the substrate S with both ends fixed by compressing holders 426 and 526 on the fixing holders 416 and 516.

[114] Additionally, it can be appreciated that as the clamping length for the substrate S is increased, the sagging amount of the substrate S is decreased.

[115] As a result, it can be seen that for the longer sides of the substrate S seated on the fixing holders 416 and 516, when the tensile force is applied to one side of the substrate S with both sides thereof fixed by the compressing holders 426 and 526, the sagging amount of the substrate S is lower than when the substrate S is seated on the fixing holders 416 and 516 without applying any force thereto or when both sides of the substrate S are fixed by the compressing holders 426 and 526 without applying the tensile force. Additionally, as the clamping length for the substrate S is increased, the sagging amount of the substrate S is decreased.

[116] Furthermore, it can be also seen that for the shorter sides of the substrate S seated on the fixing holders 416 and 516, when the tensile force is applied to one side of the substrate S with both sides thereof fixed by the compressing holders 426 and 526, the sagging amount of the substrate S is lower than when the substrate S is seated on the fixing holders 416 and 516 without applying any force thereto or when both sides of the substrate S are fixed by the compressing holders 426 and 526 without applying the tensile force. Additionally, as the clamping length for the substrate S is increased, the sagging amount of the substrate S is decreased. Meanwhile, when fixing the longer sides of the substrate, the sagging amount is lower that when fixing the shorter sides.

[117] Accordingly, operation of the substrate mounting platen 400 according to the second embodiment is performed in such a manner that when a substrate S is seated on the fixing holders 416 and 516 of the substrate fixing parts 410 and 510 provided at both sides of the substrate mounting platen 400, as shown in Figs. 4 and 5, air is injected into the vertical driving member 428 or 528 provided to both sides of the substrate fixing parts 410 and 510, respectively, thereby lowering the moving shafts of the vertical driving member 428 or 528, in order to fix the substrate S on the fixing holders 416 and 516, whereby the compressing holders 426 and 526 are lowered, and fix both sides of the substrate S on the fixing holders 416 and 516. Then, one side of the substrate S with both sides fixed by the compressing holders 426 and 526 is stretched by operating the horizontal driving member 554 equipped to move the substrate fixing part 510 provided at one side of the base. [118] Here, the substrate S interposed between the fixing holders 416 and 516 and the compressing holders 426 and 526 is firmly fixed therebetween, and the one side of the substrate S is moved outwardly through operation of the horizontal driving member 554, so that it is located horizontally without sagging due to the dead weight.

[119] Accordingly, during the deposition process for the substrate within the chamber of the apparatus for depositing the organic material, the substrate S is stretched in the horizontal direction upon mounting the substrate S on the substrate mounting platen 400 so that the substrate S can be prevented from sagging due to the dead weight.

[120] Referring to Fig. 9, a method for depositing an organic material according to the present invention comprises step S600 of conveying a substrate into a chamber; step S610 of fixing both sides of the substrate; step S620 of stretching one side of the substrate; step S630 of depositing the organic material on the substrate; and step S640 of conveying the substrate from the chamber.

[121] Step S600 of conveying the substrate into the chamber is a step for conveying a substrate S on the fixing holders 416 and 516 of the substrate fixing parts 410 and 510 of the substrate mounting platen 400 within a chamber 110 by use of a conveying means (not shown) provided at the outside of the chamber 110.

[122] Step S610 of fixing both sides of the substrate is a step for fixing both sides of the substrate S seated on the substrate fixing parts 410 and 510 by use of the vertical driving members 428 and 528.

[123] Step S620 of stretching one side of the substrate is a step for outwardly stretching one side of the substrate S by use of the horizontal driving member 554 of the tensile force applying part 550 provided to the substrate fixing part 510 while both sides of the substrate S are fixed by the substrate fixing parts 410 and 510.

[124] Step S630 of depositing the organic material on the substrate is a step for evaporating the organic material with heat supplied from a heater (not shown) and depositing the evaporated organic material onto the substrate S.

[125] Step S640 of conveying the substrate from the chamber is a step for conveying the completely deposited substrate S out of the chamber.

[126] Embodiment 3

[127] Although not shown in the drawings, an apparatus for depositing an organic material according to a third embodiment of the invention comprises a chamber (not shown) in which a substrate S having a large area is loaded and subjected to a deposition process; a substrate mounting platen 600 provided at an upper portion of the chamber for preventing the substrate S from sagging in a state that both ends of the substrate S are fixed; and a rotational lifter (not shown) coupled to the top surface of the chamber for rotating the substrate S such that the organic material can be uniformly distributed over the substrate S within the chamber during evaporation of the organic material.

[128] The apparatus for depositing an organic material according to the third embodiment has the construction and function similar to those of the first and second embodiments, except for some components, such as the substrate mounting platen 600 and the like, and thus detailed description of the similar constructions of the apparatus according to the third embodiment will be omitted.

[129] Referring to Figs. 10a, 10b and 10c, in the third embodiment, the substrate mounting platen 600 comprises a stationary holder 610, a movable holder 612, compressing holders 620 and 622, at least one pair of vertical driving members 630, at least one horizontal driving member 632, and substrate contact holders 640.

[130] The stationary holder 610 has a plate shape extended longitudinally, and is bent downwardly at one end.

[131] The movable holder 612 is horizontal to the stationary holder 610, and is connected at one end to the stationary holder 610 by means of the horizontal driving member 632 while being bent downwardly at the other end such that a bent portion of the movable holder 612 faces a bent portion of the stationary holder 610. The movable holder 612 is shorter than the stationary holder 610.

[132] The compressing holders 620 and 622 can be raised or lowered such that they can contact or be separated from the bottom surface of the stationary holder 610 and the movable holder 612, and have symmetrical "L"-shaped cross-sections.

[133] The pair of vertical driving members 630 may be a bolt or a pneumatic cylinder. The vertical driving members 630 compress or decompress the substrate S interposed between the substrate contact holders 622 by rotating the bolt manually, or by reciprocating a cylinder rod of the cylinder automatically, thereby allowing the substrate S to be mounted on the substrate mounting platen 600. That is, in the case where the vertical driving members 630 are the bolts, the compressing holders 622 are brought into contact with or separated from the stationary holder 610 and the movable holder 612 through operation of a thread on the bolts by rotating the bolts.

[134] Plural pairs of vertical driving members 630 may be equipped to one side of an upper surface of the stationary holder 610 and the movable holder 612, respectively. Meanwhile, in the case where vertical driving members 630 are pneumatic cylinders, the cylinder rods penetrate the side of the upper surface of the stationary holder 610 and the movable holder 612 in the vertical direction, and are fixed at leading ends thereof in the stationary holder and the movable holder while facing one other.

[135] The vertical driving member 632 may be a bolt or a pneumatic cylinder. The vertical driving member 632 compresses or decompresses the substrate S interposed between the substrate contact holders 622 by rotating the bolt manually, or by reciprocating a cylinder rod of the cylinder automatically, thereby allowing the substrate S to be mounted on the substrate mounting platen 600. That is, in the case where the vertical driving member 632 is the bolt, the compressing holders 622 are brought into contact with or separated from the stationary holder 610 and the movable holder 612 through operation of threads on the bolt by rotating the bolt.

[136] A plurality of horizontal driving members 632 may be equipped to an upper portion of an outer side of the movable holder 612. Meanwhile, in the case where the horizontal driving member 632 is the pneumatic cylinder, the cylinder rod penetrates the upper portion of an outer side of the movable holder 612 in the horizontal direction, and is fixed at the leading end thereof.

[137] The substrate contact holders 640 are equipped to opposite inner edges of the stationary holder 610, the movable holder 612, and the compressing holders 620 and 622. Each of the substrate contact holders 640 is made of a soft silicon pad or rubber providing a highly frictional force, thereby preventing damage of the surface of the substrate S.

[138] Additionally, each of the substrate contact holders 640 has a surface slanted downward at an angle of θtoward the outside, as shown in Fig. 11, so that when mounting the substrate S on the substrate contact holders 640, initially, the substrate S is fixed thereon in a protruded shape at respective seating positions. However, when one side of the substrate S is stretched, sagging of the substrate S is prevented, thereby allowing the substrate S to be maintained as an approximately flat surface.

[139] Here, the angle of each substrate contact holder 640 is preferably in the range of 0 - 90°.

[140] Accordingly, when fixing the substrate S to the substrate mounting platen 600 according to the third embodiment, the substrate S is conveyed upon the substrate mounting platen 600 of the apparatus (not shown) for depositing the organic material by use of a conveying means (not shown) provided at the outside of the chamber 110, and is seated on the substrate contact holders 640 equipped to the compressing holders 620 and 622. At this time, the center of the substrate S sags due to the dead weight of the substrate S.

[141] Then, as shown in Fig. 10b, the plurality of vertical driving members 630 provided on one side of the upper surface of the stationary holder 610 and the movable holder 612 facing the stationary holder 610 are operated to raise the compressing holders 620 and 622, in which the leading ends of cylinder rods of the vertical driving members 630 are fixed, so that the substrate S interposed between the compressing holder 620 and the stationary holder 610 and between the compressing holder 622 and the movable holder 612 is fixed at both sides thereof. At this time, slight sagging occurs at the center of the substrate S. Here, when fixing the substrate S, the substrate contact holders 640 made of the soft material and provided at upper and lower surfaces of the substrate S prevents damage to the surface of the substrate S.

[142] Then, as shown in Fig. 10c, the plurality of horizontal driving members 632 provided to the outer wall of the movable holder 612 are operated to move the movable holder 612 outwardly so as to be separated from the stationary holder 610, together with the compressing holder 622 supporting the substrate S from below the movable holder 612. That is, one side of the substrate S is fixed by the substrate contact holders 640 equipped to the stationary holder 610 and the compressing holder 620, and the other side of the substrate S is fixed by the substrate contact holders 640 equipped to the movable holder 610 and the compressing holder 622. At this time, when the other side of the substrate S fixed by the movable holder 610 and the compressing holder 622 is moved outwardly through operation of the horizontal driving members 632, the tensile force is applied to the other side of the substrate S, thereby allowing the substrate to be supported horizontally.

[143] Alternatively, as shown in Fig. 12a, after fixing all four sides of the substrate S, the tensile force may be applied to the four sides of the substrate S in four directions, thereby preventing the substrate S from sagging.

[144] Alternatively, as shown in Fig. 12b, after compressing all four edges of the substrate S, the tensile force may be applied to the edges of the substrate diagonally. As such, since the concept of the invention as described above can be expanded in any direction, the present invention may be applied broadly.

[145] Furthermore, the present invention may also be applied to a flexible substrate, such as a plastic substrate and a stainless steel substrate, as well as the brittle glass substrate.

[146] Industrial Applicability

[147] As apparent from the above description, according to the present invention, after the substrate is mounted on substrate mounting platen within the chamber, the tensile force is applied to the substrate by moving one side of the substrate outwardly while both sides of the substrate are fixed, thereby preventing the substrate from sagging due to dead weight of the substrate, even if the substrate has a large area.

[148] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] An apparatus for depositing an organic material, comprising: a chamber having an internal space shielded from the outside, an entrance provided at one side of the chamber to allow a substrate to be conveyed into or out of the chamber, and a gate for opening or closing the entrance; a substrate mounting platen provided at an upper portion of the chamber for applying tensile force to a substrate in order to prevent the substrate from sagging by fixing both ends of the substrate conveyed into the chamber via compressing force and moving one side of the substrate having both ends in a fixed state towards the outside; a rotational lifter coupled to a center of an upper surface of the substrate mounting platen for rotating, lifting or lowering the substrate mounting platen; and a heater and an organic material boat provided at a lower portion of the chamber for vaporizing the organic material to the substrate.

[2] The apparatus as set forth in claim 1, wherein the substrate mounting platen comprises: a substrate seating holder provided inside the substrate mounting platen, and adapted to allow one side of the substrate seating holder to be separated from the other side, the substrate seating holder having a plate shape penetrated at the center thereof such that four sides of the substrate can be seated on a through portion defined in the substrate seating holder; a compressing holder provided above the substrate mounting platen so as to be raised or lowered, and adapted to compress both sides of the upper surface of the substrate when being lowered, and to allow one side of the compressing holder at one side of the substrate to be separated from the other side co-linear with the one side of the substrate seating holder, the compressing holder having a plate shape penetrated at the center thereof; a first driving member provided downwardly above either side of an upper surface of the compressing holder for compressing or decompressing an associated side of the upper surface of the substrate according to supply or discharge of air; and a second driving member located orthogonally to the first driving member and fixed to the one side of the compressing holder for linearly reciprocating the substrate seating holder and the compressing holder, each of which is in a state that the one side thereof is separated from the other side, according to supply or discharge of air, such that the one side of the substrate with both ends thereof fixed by the compressing holder is stretched, thereby preventing the substrate from sagging, through linear reciprocation.

[3] The apparatus as set forth in claim 2, wherein the substrate seating holder is provided with a substrate aligning member.

[4] The apparatus as set forth in claim 3, wherein the substrate aligning member comprises: four positioning cylinders located at two adjoining sides of the substrate such that two positioning cylinders are located at opposite ends of one side, respectively, each positioning cylinder providing a reference point at a fixed position; and four aligning cylinders located at the other two adjoining sides of the substrate such that aligning cylinders are located at opposite ends of one side so as to be reciprocated, the aligning cylinders aligning the substrate by compressing two adjoining sides of the substrate and moving the substrate to the position of the positioning cylinders.

[5] The apparatus as set forth in claim 4, wherein each of the first and second driving members comprises: a plate-shaped base; fixing plates positioned upright at both sides of an upper surface of the base; a moving plate located between the fixing plates so as to reciprocate therebetween and having a shaft formed at the center of a front face of the moving plate so as to penetrate the fixing plate in front of the moving plate; a bellows provided between the moving plate and the fixing plate at the rear of the moving plate with both ends of the bellows fixed to the moving plate and the fixing plate, respectively, and adapted to linearly move the shaft of the moving plate forward according to a volume increase occurring when the bellows is filled with air; an air injection nozzle for injecting air into the bellows from the outside; and a spring provided around the shaft between the moving plate and the fixing plate so as to impart restoration force to the bellows during shrinkage of the bellows upon discharge of the air from the bellows.

[6] The apparatus as set forth in claim 1, wherein the substrate mounting platen comprises: a plate-shaped base; a pair of substrate fixing parts provided to both sides of the base while being in parallel to both sides of the base for applying the compressing force to the substrate, one of the substrate fixing parts being stationary and the other substrate fixing part being movable; a tensile force applying part provided orthogonal to an outer surface of the movable substrate fixing part for applying tensile force to the substrate by moving the substrate fixing part outwardly.

[7] The apparatus as set forth in claim 6, further comprising: a controller for controlling the compressing force supplied from the substrate fixing part and the tensile force supplied from the tensile force applying part.

[8] The apparatus as set forth in claim 7, wherein each substrate fixing part comprises: an elongated lower plate longer than a fixed portion of the substrate; a plate-shaped fixing holder located above the lower plate and adapted to allow the substrate to be seated on an upper surface thereof, the fixing holder having the same shape as that of the lower plate; a position fixing plate provided at one side of the fixing holder while being extended longitudinally, the position fixing plate having an L-shaped cross- section; a driving member fixing plate spaced from the position fixing plate while being located at the center above the fixing plate; a compressing holder adapted to be raised or lowered in a space between the driving member fixing plate and the fixing holder to compress or decompress the upper surface of the substrate seated on the fixing holder, the compressing holder having a plate shape extended longitudinally; and a vertical driving member provided at the center of an upper surface of the driving member fixing plate to raise or lower the compressing holder so as to apply the compressing force to the substrate, the vertical driving member having a moving shaft fixed at its leading end to the compressing holder.

[9] The apparatus as set forth in claim 8, wherein the substrate mounting platen further comprises: a pair of horizontal moving guides under the substrate fixing parts for moving the substrate fixing parts such that a distance between the substrate fixing parts can be adjusted according to a size of the substrate.

[10] The apparatus as set forth in claim 9, wherein the vertical driving member is provided with a first pressure gauge on the moving shaft.

[11] The apparatus as set forth in claim 10, wherein the first pressure gauge is at least one load cell.

[12] The apparatus as set forth in claim 11, wherein the vertical driving member is a hydraulic or pneumatic cylinder.

[13] The apparatus as set forth in claim 12, wherein the tensile force applying part comprises: a stationary lateral plate fixed to the lower plate and an outer wall of the fixing holder of the substrate fixing part; a driving member fixing lateral plate spaced outwardly from the stationary lateral plate and positioned upright in a fixed state at an edge of one side of the base; and a horizontal driving member equipped to an outer wall of the driving member fixing lateral plate to move the movable substrate fixing part in the horizontal direction so as to apply the tensile force to the substrate, the horizontal driving member having a moving shaft fixed at its leading end to the movable substrate fixing part.

[14] The apparatus as set forth in claim 13, wherein the horizontal driving member is provided with a first pressure gauge on the moving shaft.

[15] The apparatus as set forth in claim 14, wherein the first pressure gauge is at least one load cell.

[16] The apparatus as set forth in claim 15, wherein the vertical driving member is a hydraulic or pneumatic cylinder.

[17] The apparatus as set forth in claim 11 or 15, wherein the at least one load cell is a plurality of load cells.

[18] The apparatus as set forth in claim 17, wherein the vertical and horizontal driving members apply different compressing force and tensile force to the substrate according to a thickness of the substrate, respectively.

[19] The apparatus as set forth in claim 1, wherein the controller is provided with a display electrically connected to the controller to output a result of detection by the first pressure gauge and the second pressure gauge in numerical form.

[20] A method for depositing an organic material, comprising the steps of: conveying a substrate to a fixing holder of a substrate mounting platen provided within a chamber; fixing both sides of the substrate seated on substrate fixing parts at both sides of the substrate by use of a vertical driving member; outwardly stretching one side of the substrate by use of a horizontal driving member of a tensile force applying part provided to one of the substrate fixing parts fixing both sides of the substrate; depositing the organic material on the substrate seated on substrate fixing parts while being stretched; and conveying the completely deposited substrate from the chamber.

[21] The apparatus as set forth in claim 1, wherein the substrate mounting platen comprises: a stationary holder having a plate shape extended longitudinally and bent downwardly at one end; a movable holder horizontally connected to the stationary holder and bent downwardly at the other end such that a bent portion of the movable holder faces a bent portion of the stationary holder; compressing holders adapted to be raised or lowered such that they can contact or be separated from the bottom surface of the stationary holder and the movable holder, the compressing holders having "L"-shaped cross-sections opposite to each other, respectively; a plurality of vertical driving members equipped to one side of an upper surface of the stationary holder and the movable holder, respectively, such that the vertical driving members penetrate the upper surface of the stationary holder and the movable holder in the vertical direction and are fixed at leading ends thereof in the stationary holder and the movable holder while facing one other; a plurality of horizontal driving members equipped to an upper portion of an outer side of the movable holder such that the horizontal driving members penetrate the upper portion of an outer side of the movable holder in the horizontal direction, and are fixed at leading ends thereof in the movable holder; and substrate contact holders equipped to opposite inner edges of the stationary holder, the movable holder, and the compressing holders.

[22] The apparatus as set forth in claim 21, wherein each of the vertical driving members is one of a bolt and a pneumatic cylinder.

[23] The apparatus as set forth in claim 22, wherein each of the substrate contact holders is made of a soft material providing a high frictional force, and has a surface slanted downward at a predetermined angle toward the outside, thereby minimizing sagging of the substrate.

[24] The apparatus as set forth in claim 23, wherein each of the substrate contact holders is made of a silicon pad or rubber.

[25] The apparatus as set forth in claim 24, wherein the angle is preferably in the range of 0 - 90°.