KR20190077424A - A mask holder with controlled adjustment - Google Patents

Abstract

The present invention relates to a holder for a mask (3), characterized in that in order to limit deposition of the layer onto sections of a predetermined surface by means of the shape and position of the mask (1) (4, 4 ', 4' ', 4' '', 16) of the frame (3) of the holder are located on the surface to be coated of the mask (1 ') of the mask (1). The following innovations are provided: a sensor 5 for detecting the actual position of the mask 1 with respect to the substrate 2, at least one second section (not shown) of the frame 3, 7, 8) for changing the position of the at least one first section (4) of the frame (3) with respect to the longitudinal axis (Z ', Z' To change the actual-position of the mask (1) to the target-position direction of the mask (1) by changing the actual position of the mask (1). In addition, the present invention relates to a method for adjusting the position of the mask, in which a control circuit is used.

Description

A mask holder with controlled adjustment

The present invention relates to a holder for a mask, wherein the mask lies on a surface to be coated of the substrate in a coating process, in order to limit deposition of the layer onto sections of a predetermined surface by the shape and position of the mask , Wherein the sections of the frame of the holder engage the edges of the mask by a changeable tension that deforms the mask.

In addition, the present invention relates to a method for adjusting the position of a mask, said mask being adapted to position the substrate in a coating process in order to limit deposition of the layer onto sections of a predetermined surface by means of the shape and position of the mask Is placed on the surface to be coated, wherein a tension is imparted to the edges of the mask by the sections of the frame of the holder to deform the mask.

The apparatus according to the invention and the method according to the invention are used in the case of depositing structured layers in the lateral direction on a substrate, wherein the material forming the layers is a gas, in particular organic molecules in vapor form, Into the process chamber of a CVD- or PVD reactor. The gaseous starting materials condense or react on the surface of the substrate, forming a layer at this time. The present invention relates in particular to an apparatus which can be used when manufacturing LCD-displays or OLED-displays. The mask used here has windows separated by webs, which expose discrete sections of the surface of the substrate. Different starting materials are deposited on such surface sections and the starting materials emit different colors in electrical excitation. The mask consists of a metal plate structured in the lateral direction of the thin sidewall and the mask is tensioned by the tension directed onto the edge of the mask in the mask extension direction such that the windows are in their intended positions. A mask frame comprising tensile elements is described in US 2014/0158044 Al for which the edges of the rectangular mask are fixed and to impart a respective directed tension on the mask at different locations.

 In WO 2007/133252 A2 it is known to adjust the temperature when connecting the mask to the mask frame. In this case, the frame is temperature-controlled at different temperatures, and consequently, lateral directional tensions are formed in the mask surface due to different temperature expansion coefficients at the time of temperature change.

A method for making a mask that is stretched when the mask is manufactured is disclosed in US 7,765,669 B2.

US 2016/0376703 A1 describes a method and apparatus for adjusting a mask against a surface of a substrate, wherein register marks of the mask or the substrate are detected by a CCD-sensor, and in the form of a screw spindle The positions of the opposing sections of the holder are changed by the adjusting members of the holder.

A holder for a mask is known from US 2015/0068456 A1. The holder has four frame pieces, and the position of the frame pieces relative to the base plate can be changed by a screw spindle or a piezoelement.

The material of the mask and the material of the frame may have different thermal expansion coefficients, in order to tension the mask by thermally adjusting the frame supporting the mask at the edge, resulting in a temperature change causing deformation of the mask . By the desired deformation, the mask can be provided in a real-position to a target-position, because the provision of the tension causes the opposed edge sections of the mask to be spaced apart from one another. Other adjustment members may be provided to apply a tension directed onto the edge of the mask. Due to the different and especially the individual effects on the frame and the substrate, in particular the mechanical deformation of the frame or of the mask due to temperature regulation of the substrate or mask is not computationally determined.

The object of the present invention is to provide a method for improving the position of the mask as compared with the prior art, preferably by improving the use of a holder for a mask known in the prior art.

This problem is solved by the invention as set forth in the claims. The subordinate claims not only represent preferred improvements of the invention presented in the parallelly arranged claims, but also represent independent solutions to the problem of preferably improving conventional holders in use.

Prior and substantially, it is proposed that a control circuit be used to adjust the position of the mask. The control circuit according to the present invention comprises sensors for detecting the actual-position of the mask with respect to the substrate. The control circuitry also includes adjustment members for changing the position of the at least one first section of the frame relative to the at least one second section of the frame. Wherein the control circuit further comprises a control device for controlling the adjustment members such that the actual-position of the mask is changed to the target-position direction by changing the tension on the edge of the mask, Are generated. As the control circuit, a PID-control circuit may be considered. The adjustment members preferably change the spacing of the two distances facing each other, preferably by changing the temperature of one or more sections of the frame. The frame may be a rectangular frame supporting a rectangular mask. The frame forms opposing frame pieces. By varying the temperature of one of the frame pieces, the length of the frame piece is changed, thereby changing the spacing of two opposing sections of the frame. The sensors are preferably optical sensors. Such sensors include imaging sensors, which include an imaging optics for producing a surface image of the frame on a sensor, for example on a CCD-sensor. The actual-position of the mask and in particular the actual-position of the edge region of the mask can be detected by image evaluation. The adjusting members are preferably heating and / or cooling elements. Each frame piece may have cooling channels and / or heating channels. Only cooling channels may be present, or only heating channels may be present. However, it is also possible that the cooling-and-heating channels are arranged side by side in the extending direction of the frame piece. Each frame piece can be temperature controlled separately from each other frame piece. However, mechanical means may be provided instead of the heating and / or cooling elements to change the spacing of the two frame sections. Sections spaced apart from each other by the adjustment members are considered edge zones of the frame or mask, wherein the mask and the frame are connected to each other by tension transmission elements. The tension transmission elements may be shape fitting means such as pins, screws, and the like. However, it is also possible that the edge of the mask is connected to the section of the frame by forced or material coupling. In one refinement of the invention, the sensors interact with the register marks. In particular, the first register marks assigned to the corner areas of the mask may be provided. In this case, window-like openings in the mask can be considered. Second register marks assigned to the substrate may be provided. The second register marks may be directly assigned to the substrate, or may be indirectly assigned to the substrate. The register marks directly assigned to the substrate may be, for example, color zones on the surface to be coated of the substrate. However, register marks indirectly assigned to the substrate may be formed by a substrate holder that supports the substrate. These register marks can also be visually distinguishable marks. The register marks are detectable by an optical sensor through a transparent substrate. By means of the adjusting members the register marks are co-ordinated by changing the direction and magnitude of the tension exerted on the edge of the mask. This is accomplished through a control device of the control circuit, which preferably obtains actual values according to the position of the register marks disposed in the corner areas and outputs control instructions to the adjustment members. The mask can be made of invar, and the frame can be made of special steel. The expansion coefficient of special steel is larger than the coefficient of expansion of the substrate when it is made of glass. The mask made by invar by making the mask frame temperature-adjustable within a range of 20 ° C to 60 ° C can be mechanically stretched so that the register marks become coherent. By making adjustments over the closed control period, it is not necessary to determine the influence factors computationally. The measuring device formed by the sensors may comprise up to four CCD-cameras arranged at the corners of the substrate or frame. The exact positions of the substrate and the mask at the corners are detected, in particular, by the aforementioned register marks. In these positions, different thermal or mechanical length expansions are detected by the sensors, in particular by the cameras. From such values, the control device detects a target value of the temperature of the mask frame. The mask frame is provided with the target value. Subsequently, the position change is detected by the sensors, and in the further control step, the approach of the actual value approaching the target value is improved. In this case, different sections of the frame may have different temperatures. The control of the mask expansion and the mask position preferably includes two steps. In the first step, the mask center and the substrate center are aligned with respect to each other. The coordinate system of the mask and other zero points in the coordinate system of the substrate may be combined. If the mask marks and the register marks disposed at the corners of the substrate after the alignment of the zeros are different from each other, in the second step the mask is deformed in its own elastic region until the register marks of the substrate and the mask are cohered. The force for generating the stretching of the mask may be mechanically made, or may be achieved by temperature control of the mask or the mask frame. The previously described two-stage positioning of the mask is carried out only once, and only the temperatures detected earlier in the individual mask frame sections at the time of substrate replacement are used. The spacing of the frame sections by changing the temperature can be achieved by active heating or active cooling. In a deposition process in which a substrate is cooled in a condensing process to deposit a layer, temperature control may be achieved by reduced cooling power.

Embodiments of the present invention will now be described.
1 is a schematic diagram of a control circuit according to the present invention,
Figure 2 is a schematic view of several elements of a coating apparatus,
3 is a partially enlarged cross-sectional view of the cutout III of Fig. 2,
4 is a plan view of the mask frame 3,
5A to 5D are partial enlarged cross-sectional views of the cutouts Va to Vd prior to positioning of the mask 1 on the mask frame 3,
Figs. 6A to 6D are partial enlarged cross-sectional views of the cutouts Va to Vd of Fig. 4 after adjustment of the mask,
7 is a plan view of the mask frame 3 in a further embodiment.

1 schematically shows a structure of a control device according to the present invention. A rectangular substrate 2 is placed on a rectangular substrate holder 10. A mask (1) is placed on the exposed surface of the substrate (2), and the mask comprises a plurality of windows separated from each other by webs. The mask edges 1 'of the mask 1 protrude above the side edges of the substrate 2 and the substrate holder 10.

The substrate holder 10 is surrounded by a rectangular frame 3 comprising four frame pieces 4, 4 ', 4' ', 4' ''. The edge 1 'of the mask 1 is formed in the frame 1 so that a tension directed in the side-extending direction of the mask 1 can be transmitted from the frame pieces 4, 4' And fixed to the frame 3 in the piece 4.

A cooling channel 7 and a heating channel 6 are disposed in each of the four frame pieces 4, 4 ', 4' ', 4' ''. The cooling liquid can be perfused through the cooling channel 7 and the heating liquid can be perfused through the heating channel 6. [ By adjusting the flow rates of the coolant or the heating agent flowing through the channels 7 and 8, the temperature of each frame piece 4, 4 ', 4' ', 4' '' can be individually set . The mask 1 is made of invar and has a lower thermal expansion coefficient than the frame 3 or the frame pieces 4 and 4 ' Resulting in a change in the mechanical tension.

The flow rates of the coolant or the heating agent flowing through the channels 7, 8 are controlled by the control device 9. For this purpose, for example, retractable valves or control valves may be provided and the flow rate of the coolant adjusted to a specific temperature by the valves or the flow rate of the heating agent adjusted to a specific temperature may be provided to the channels 7, Lt; / RTI >

In particular, optical sensors in the form of CCD-cameras 5 are provided by which the actual value of the position of the mask, in particular in the four corner regions of the frame 3, is detected. Here, register marks 11 and 12, which are not shown in FIG. 1, are located and the register marks are coherent to reach the target-position of the mask 1. The first register marks 11 are formed by the mask and the second register marks 12 are formed by the substrate. The CCD-cameras 5 transmit the actual values to the control device 9.

Instead of the temperature regulating devices 7, 6 described above in which the temperature regulated liquid flows through the cooling channels 7 or the heating channels 6, other temperature regulating means, for example resistive heaters or Peltier-cooling elements may also be provided.

FIG. 2 shows a cross-sectional view of a coating system in which gaseous starting materials are introduced into the process chamber from the gas discharge openings of the gas inlet member 15 in the form of a showerhead. The gas inlet member 15 is adjusted to an elevated temperature at which the organic vapor contained in the process gas is not condensed.

The substrate holder 10 has cooling elements that are not shown and the substrate holder 10, which can be placed below or above the gas inlet member 15 by the cooling elements, To a temperature at which the substrate is condensed on the surface of the substrate holder (2), the substrate being placed on the broad side of the substrate holder (10) towards the process chamber.

The substrate 2 is covered by a mask 1 comprising windows 13 and webs 14 restricting the windows 13. There is considered a shadow mask in which the surface is brought into contact with the wide side surface of the substrate 2 to be coated.

Fig. 3 shows one edge region of the four edge regions of the rectangular frame 3 supporting the mask 1. Fig. The edge 1 'of the mask 1 is connected to the frame piece 4 of the frame 3 by tension transmission elements 17. In this case, a shape-fitting element or a weld seam may also be considered.

The mask 1 has a first register mark 11 formed as a window in a corner area. The substrate 2 is provided with a second register mark 12 which is visually distinguishable by the periphery so that the two register marks 11 and 12 Can be detected.

Fig. 4 is a cross-sectional view of a mask 1 or a frame 1 ' which fixes the mask 1 at an edge 1 ' by means of four frame pieces 4, 4 ', 4 " (3). ≪ / RTI > Figs. 5A to 5D are enlarged views of the corner areas of the mask 1, which are centered in the first step and placed on the substrate 2, respectively. The positions of the register marks 11, 11 ', 11' 'and 11' '' of the mask 1 correspond to the positions of the register marks 12, 12 ', 12' 'and 12' '' ).

As shown in Figures 6a to 6d, the temperature of the frame 3, especially the frame pieces 4, 4 ', 4' ', (Z, Z ', Z' ', Z' '') in separate directions and by individual strengths, relative to each other, by displacing the sections of the mask 1 ', 4' The register marks 11, 11 ', 11' ', 11' '' may be provided to the corner marks of the register marks 12, 12 ', 12' ', 12 " ').

However, by controlling the temperature of the frame pieces 4, 4 ', 4' 'and 4' '', the tension Z, Z ', Z' It is also possible to apply a tension in one direction uniformly to the entire edge of the mask as a result, by providing it to the edge edge of one of the respective edge edges. At this time, the register marks used for the control may also be arranged at the edge of the mask 1 or the substrate 2. [ The register marks are concatenated by the control device.

This congruence of the register marks 11, 11 ', 11 ", 11' '', 12, 12 ', 12", 12' '' (11, 11 ', 11', 12 '') with respect to the register marks (12, 12 ', 12 " '', 11 '' ') are detected and subsequently the coolant flow rate or the heater flow rate flowing through the adjustment members, for example the cooling channels 7 or the heating channels 6, The actual value is set to be close to the target value. The successive adjustment steps are repeated until sufficient mating of the register marks 11, 11 ', 11' ', 11' '', 12, 12 ', 12 ", 12' . The temperatures of the frame pieces or the flow rates of the coolant or heating agent flowing into the frame pieces are stored when the mask 1 is placed on the substrate 2 to be precisely matched. Accordingly, adjustment of the mask may be performed only once. In this case, when the mask is additionally used in a production mode in which a plurality of substrates are successively coated, only the detected temperatures of the frame pieces 4, 4 ', 4' ', 4' '' do.

In the embodiment shown in Figure 7, the corner areas 16 where the register marks 11 and 12 are provided are separated by the piezo element devices 8 into a frame extending between the corner areas 16 Are displaced relative to the pieces (4). The corner areas are formed by corner members that may include tension transmission elements.

The embodiments described above are used to illustrate the inventions as generally described by the present application, and the inventions also independently improve the prior art by at least the following combinations of features:

A sensor 5 for detecting the actual position of the mask 1 relative to the substrate 2, at least one second section 4 'of the frame 3 relative to at least one second section 4' By changing the adjusting members 6, 7 and 8 for changing the position of the mask 4 and the tension Z, Z ', Z' ', Z' '' A holder for a mask (1), characterized by comprising a control circuit including a control device (9) for changing to a target-position direction of the mask (1).

The adjusting members 6 and 7 are characterized by changing the intervals of the two frame pieces 4, 4 ', 4' 'and 4' '' of the rectangular frame 3, which are opposed to each other, A holder for a mask.

Characterized in that the sensors (5) are optical sensors.

Characterized in that the sensors (5) comprise an optical imaging system, in particular CCD-cameras.

Characterized in that the adjusting members comprise heating and / or cooling elements (6, 7).

Characterized in that the heating and / or cooling elements (6, 7) are mutually separated channels through which cooling liquid and / or heating liquid can flow.

Characterized in that the adjustment members are piezo elements (8) arranged between the sections (4, 4 ', 4 ", 4", 4 " holder.

Characterized in that the mask (1) comprises first register marks (11) and the first register marks can co-operate with second register marks (12) comprised by the substrate (2) , A holder for a mask.

Characterized in that the register marks (11, 12) are arranged at the corners of the mask (1) or the substrate (2).

The actual-position of the mask 1 with respect to the substrate 2 is detected by the sensors 5 and the actual-position of the mask 1 is detected by the sensors 5 to drive control the adjusting members 6, Adjustment values are generated by the control circuit from the difference between the position and the target-position of the mask 1 and the adjustment values are generated by the adjustment members with respect to one or more second sections 4 ' Characterized in that the position of the at least one first section (4) of the mask (1) is changed so that the actual position of the mask (1) is close to the target-position of the mask Lt; / RTI >

The adjustment value is the temperature of the section 4, 4 ', 4' ', 4' '' of the frame 3, wherein the different sections 4, 4 ', 4 " Wherein the temperature of the mask (1) is adjusted separately from the temperature of the mask (1).

Characterized in that the first register marks (11) and the second register marks (12) arranged at the corners of the rectangular frame (3) or the rectangular substrate (2) / RTI >

All features disclosed (by themselves, but in combination with one another) are important to the present invention. Accordingly, for the purpose of accepting the features of the priority documents together with the claims of the present application, the contents of the priority documents (copies of the preliminary application) attached to the contents of the present application / . In particular to carry out a partial application based on dependent claims, features of the dependent claims characterize independent and progressive improvements of the prior art.

1 mask
1 'edge
2 substrate
3 frames
4, 4 ', 4'',4''' frame pieces, section 1
5 CCD camera
6 Heating device
7 Cooling unit
8 Piezo element
9 Control unit
10 Board Holder
11 register mark
12 register mark
13 Windows
14 Web
15 gas inflow member
16 corner member
17 Tension transmission element
Z, Z ', Z'',Z''' Tension

Claims (14)

As the holder for the mask 1,
The mask is placed on the surface to be coated of the substrate 2 in the coating process so as to confine the deposition of the layer onto the sections of the predetermined surface by the shape and position of the mask 1, The opposed sections engage the edges 1 'of the mask 1 by a changeable tension that deforms the mask 1 and the actual positions of the mask 1 relative to the substrate 2 (6, 7) for changing the position of the at least one first section (4) of the frame (3) relative to the at least one second section (4 ') of the frame (3) To change the actual-position of the mask 1 to the target-position direction of the mask 1 by changing the tension (Z, Z ', Z'',Z''' (9), characterized in that the mask holder
Said sections being formed by frame pieces (4, 4 ', 4'',4''') of a rectangular frame (3) of said holder, said adjustment members And changes the interval of the two frame pieces (4, 4 ', 4'',4''') facing each other in the rectangular frame (3) by temperature change. The method according to claim 1,
Characterized in that the sensors (5) are optical sensors. The method according to claim 1,
Characterized in that the sensors (5) comprise an optical imaging system, in particular CCD-cameras. As the holder for the mask 1,
The mask is placed on the surface to be coated of the substrate 2 in the coating process so as to confine the deposition of the layer onto the sections of the predetermined surface by the shape and position of the mask 1, The opposing sections are for the mask holder to engage with the edges 1 'of the mask 1 by a changeable tension capable of deforming the mask 1,
Characterized in that the holder comprises a frame (3) with opposing frame pieces (4, 4 ', 4 ", 4'''), the length of the frame pieces being changeable And a holder for the mask. 5. The method of claim 4,
Characterized in that adjustment members (6, 7) are provided to change said spacing. 6. The method according to any one of claims 1 to 5,
Characterized in that the adjusting members comprise heating and / or cooling elements (6, 7). The method according to claim 6,
Characterized in that the heating and / or cooling elements (6, 7) are mutually separated channels through which cooling liquid and / or heating liquid can flow. 8. The method according to any one of claims 1 to 7,
Said adjusting members are arranged in such a way that they are arranged in the longitudinal direction of the frame member 3, in particular between the sections of said frame pieces 4, 4 ', 4 ", 4" Characterized in that the holder is a piezoelements (8). 9. The method according to any one of claims 1 to 8,
The mask 1 comprises first register marks 11 and the first register marks can be co-mingled with the second register marks 12 comprised by the substrate 2 And a holder for holding the mask. 10. The method of claim 9,
Characterized in that the register marks (11, 12) are arranged at the corners of the mask (1) or the substrate (2). As a method for adjusting the position of the mask 1,
The mask is placed on the surface to be coated of the substrate 2 in the coating process so as to limit the deposition of the layer onto the sections of the predetermined surface by the shape and position of the mask 1, ) Of the mask 1 is provided by the sections of the mask 1 with respect to the substrate 2 by means of sensors 5, 1 from the difference between the actual-position of the mask 1 and the target-position of the mask 1 in order to drive control the adjusting members 6, 7, Wherein the position of the at least one first section of the frame (3) relative to the at least one second section of the frame (3) Adjust the position of the mask to be changed so that its position is close to the target-position of the mask (1) In the method,
Characterized in that the adjustment value is the temperature of the frame (3) and / or the lengths are frame pieces (4, 4 ', 4 ", 4''' A method for adjusting the position of a mask. 12. The method of claim 11,
Characterized in that the different sections of the frame pieces (4, 4 ', 4'',4''') are temperature controlled separately from each other. 13. The method according to claim 11 or 12,
Characterized in that the first register marks (11) and the second register marks (12) arranged at the corners of the rectangular frame (3) or the rectangular substrate (2) Way. A holder or method characterized by having one or more of the features of any one of claims 1 to 13.

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