JP7703683B2 - Method for manufacturing deposition mask and method for manufacturing display device - Google Patents

Description

The present invention relates to a method for manufacturing a deposition mask and a method for manufacturing a display device.

Patent Document 1 discloses a deposition mask having a frame body with multiple openings and multiple mask bodies arranged in the multiple openings. Here, one mask body is bonded to each opening via a metal layer. In such a configuration, it is necessary to position the mask body with respect to each of the multiple openings, and positioning errors may occur between the multiple mask bodies.

Patent No. 4369199

The present invention provides an advantageous technique for improving the relative positional accuracy of multiple pattern areas in a deposition mask.

A first aspect of the present invention relates to a method for manufacturing a deposition mask, the method for manufacturing the deposition mask including: a patterning step of patterning a mask substrate so that a plurality of pattern regions are formed on the mask substrate; a bonding step of bonding the mask substrate and a support substrate to form a laminate after the patterning step ; and a processing step of processing the mask substrate so that separation grooves are formed to separate the plurality of pattern regions from each other in the laminate after the bonding step.

A second aspect of the present invention relates to a method for manufacturing a display device, the method for manufacturing the display device including a deposition step of performing deposition on a substrate using a deposition mask manufactured by the deposition mask manufacturing method, and a processing step of processing the substrate that has undergone the deposition step to obtain a display device.

One aspect of the invention disclosed in this specification relates to a deposition mask comprising a support substrate having a plurality of first openings and a plurality of second openings, a plurality of masks supported by the support substrate, and a plurality of members supported by the support substrate, each mask including a pattern area exposed through any one of the plurality of first openings, and each member including an alignment mark exposed through any one of the plurality of second openings.

5A to 5C are diagrams for exemplarily explaining a method for manufacturing a deposition mask according to an embodiment. 5A to 5C are diagrams for exemplarily explaining a method for manufacturing a deposition mask according to an embodiment. 5A to 5C are diagrams for exemplarily explaining a method for manufacturing a deposition mask according to an embodiment. 5A to 5C are diagrams for exemplarily explaining a method for manufacturing a deposition mask according to an embodiment. 5A to 5C are diagrams for exemplarily explaining a method for manufacturing a deposition mask according to an embodiment. 5A to 5C are diagrams for exemplarily explaining a method for manufacturing a deposition mask according to an embodiment. 5A to 5C are diagrams for exemplarily explaining a method for manufacturing a deposition mask according to an embodiment. 5A to 5C are diagrams for exemplarily explaining a method for manufacturing a deposition mask according to an embodiment. FIG. 2 is a schematic plan view of the deposition mask according to the embodiment, as viewed from the supporting substrate side. FIG. 2 is a schematic plan view of the deposition mask according to the embodiment, as viewed from the pattern region side. FIG. 2 is a plan view illustrating a deposition mask according to an embodiment and a grating defined by the deposition mask.

The embodiments are described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicate explanations are omitted.

Below, an exemplary method for manufacturing a deposition mask according to an embodiment will be described with reference to FIGS. 1A to 1H. FIGS. 1A to 1H are schematic cross-sectional views of the structure to be described. First, a patterning process will be described with reference to FIGS. 1A to 1D. In the patterning process, the mask substrate 110 may be patterned so that a plurality of pattern regions are defined or formed on the mask substrate 110. FIG. 1A illustrates a coating process, in which a photoresist is coated on the mask substrate 110, thereby forming a photoresist film RF. The mask substrate 110 may be, for example, a silicon substrate or a glass substrate.

FIG. 1B shows a schematic diagram of a transfer process and a development process that may be performed after the coating process. In the transfer process, the pattern of the original may be transferred sequentially to a plurality of pattern formation regions PFR of the photoresist film RF using an exposure device such as a stepper or a scanner. In the transfer process, the alignment mark may also be transferred to a plurality of alignment mark regions AA of the photoresist film RF in the exposure device. The alignment mark may be transferred simultaneously with the pattern of the original. In the transfer process, the pattern of the original may be transferred sequentially to a plurality of pattern formation regions PFR while the substrate stage on which the mask substrate 110 on which the photoresist film RF is formed is driven under the coordinate system of the exposure device. In the transfer process, a plurality of alignment marks may also be transferred to a plurality of alignment mark regions AA while the substrate stage is driven under the coordinate system of the exposure device. Therefore, the pattern of the original can be transferred to each of the plurality of pattern formation regions PFR according to the positioning accuracy of the substrate stage of the exposure apparatus, and the alignment mark can be transferred to each of the plurality of alignment mark regions AA according to the positioning accuracy of the substrate stage of the exposure apparatus. Therefore, the mutual positional accuracy of the plurality of patterns transferred to each of the plurality of pattern formation regions PFR and the alignment mark transferred to each of the plurality of alignment mark regions AA is high according to the positioning accuracy of the substrate stage. In the development process, the photoresist film RF that has been subjected to the transfer process can be developed to form a resist pattern RP.

FIG. 1C shows a schematic diagram of an etching process that may be performed after the development process. In the etching process, a plurality of pattern regions PR each including a plurality of grooves 13 and a plurality of alignment marks 12 may be formed by etching the mask substrate 110 through the openings of the resist pattern RP. Since the plurality of pattern regions PR and the plurality of alignment marks 12 are formed by transferring the resist pattern RP, the mutual positional accuracy of the plurality of pattern regions PR and the plurality of alignment marks 12 is high according to the positioning accuracy of the substrate stage of the exposure apparatus. In the etching process, a plurality of grooves 13 may be formed in the mask substrate 110 so that no through holes are formed in the mask substrate 110. In this case, the thinning process described later is performed. However, in the etching process, a plurality of grooves 13 may be formed in the mask substrate 110 so that a through hole is formed in the mask substrate 110.

Figure 1D shows a schematic diagram of a resist stripping process that may be performed after the etching process. In the resist stripping process, the resist film RF may be stripped.

1E and 1F are schematic diagrams showing the bonding process. The bonding process may be performed after the patterning process. The patterning for forming the above-mentioned multiple pattern regions PR is performed on the first surface S1 of the mask substrate 110, and in the bonding process, the support substrate 120 may be bonded to the first surface S1 side of the mask substrate 110. In the bonding process, the mask substrate 110 that has undergone the patterning process and the separately prepared support substrate 120 may be bonded to form a stacked body ST. Here, in order to improve the strength of the bond between the mask substrate 110 and the support substrate 120, metal films 131 and 132 may be formed on the mask substrate 110 and the support substrate 120, respectively, before the bonding process, and the metal film 131 and the metal film 132 may be bonded to each other in the bonding process. In the bonding process, the mask substrate 110 and the support substrate 120 may be bonded to each other by, for example, atomic diffusion bonding. In the bonding process, the mask substrate 110 and the support substrate 120 can be aligned using the alignment marks 12 formed on the mask substrate 110 .

The support substrate 120 preferably has a sufficiently low linear expansion coefficient. The linear expansion coefficient of the support substrate 120 is, for example, smaller than the linear expansion coefficient of the mask substrate 110. The support substrate 120 is, for example, made of an alloy containing nickel and cobalt, and has a linear expansion coefficient of, for example, 0.5×10 ⁻⁶ (/° C.) or less. The support substrate 120 may be, for example, made of Invar. The support substrate 120 may be made of a ceramic composite material containing amorphous silicon and titanium or crystalline silicon, and has a linear expansion coefficient of, for example, 0.5×10 ⁻⁶ (/° C.) or less.

In one example, the support substrate 120 may be made of, for example, a 32Ni-5Co alloy. In this case, the linear expansion coefficient is 0.2×10 ⁻⁶ (/° C.), and when the temperature rise of the deposition mask is 30° C., the amount of expansion per 100 mm is 0.2× ^{10 −6} (/° C.)×30 (° C.)×100 (mm)=0.0006 mm=0.6 μm. In other words, deposition can be performed with sufficient positional accuracy even in the manufacture of OLED panels with pixel sizes of 10 μm or less.

The support substrate 120 may have a plurality of first openings OP1 for exposing the plurality of pattern regions PR in the laminate ST, and a plurality of second openings OP2 for observing the plurality of alignment marks 12. The plurality of pattern regions PR may be exposed through the plurality of first openings OP1, and the plurality of alignment marks 12 may be exposed through the plurality of second openings OP2.

The bonding process is carried out without heating or cooling. In another aspect, the bonding process may be carried out within a temperature range of 7°C or more and 39°C or less. Such conditions are advantageous for keeping the warping of the laminate ST or deposition mask after the bonding process within an acceptable range.

Figure 1G shows a schematic diagram of the thinning process. The thinning process can be performed between the bonding process and the processing process described below. In the thinning process, the mask substrate 110 can be thinned so that the multiple grooves 13 are changed into multiple through holes. In the thinning process, the mask substrate 110 can be thinned, for example, by grinding or etching the second surface S2 (the surface opposite to the first surface S1) of the mask substrate 110.

FIG. 1H shows a schematic diagram of the processing step. In the processing step, the mask substrate 110 can be processed so that the plurality of pattern regions PR (masks) in the laminate ST and the plurality of members 16 each including an alignment mark 12 are separated from each other. More specifically, in the processing step, a separation groove 15 can be formed between the plurality of pattern regions PR (masks) and the plurality of members 16 so that the plurality of pattern regions PR and the plurality of members 16 are separated from each other. This completes the deposition mask M. The separation groove 15 makes it difficult for the support substrate 120 to be affected by the deformation of the plurality of pattern regions PR due to temperature change, and also makes it difficult for the deformation of the support substrate 120 due to temperature change to be affected by the plurality of pattern regions PR. After the separation step, the plurality of pattern regions PR separated from each other are supported by the support substrate 120. It is preferable that the width of the separation groove 15 (the width in a direction perpendicular to the direction in which the separation groove 15 extends along the edge of the pattern region PR between adjacent pattern regions PR) is larger than the width of the multiple grooves 13 (the width in the same direction).

The deposition mask M that can be connected in the above manner is suitable for manufacturing a display device. A method for manufacturing such a display device can include a deposition process in which deposition is performed on a substrate using the deposition mask M, and a processing process in which the substrate that has undergone the deposition process is processed to obtain a display device. In the deposition process, for example, an organic electroluminescent material can be deposited on the substrate through a plurality of through-holes in the deposition mask.

In one example, the thickness of the mask substrate 110 before the thinning process is 775 μm, and the thickness of the mask substrate 110 after the thinning process is 30 μm. In this case, in the patterning process, the multiple grooves 13 can be formed to have a depth that is, for example, 10% greater than the thickness of the mask substrate 110 after the thinning process (i.e., 30 μm × (100 + 10) / 100 = 33 μm).

In one example, before the bonding process is performed, metal films 131, 132 such as titanium may be formed on the mask substrate 110 and the support substrate 120 by sputtering or deposition in a vacuum chamber having an ultimate vacuum pressure of 1×10 ⁻⁴ Pa or less. The thickness of the metal films 131, 132 may be within a range of, for example, 0.3 to 5 nm.

The mask substrate 110 and the support substrate 120 are typically made of different materials. In one example, the mask substrate 110 is made of silicon, and the support substrate 120 is made of an alloy of 32Ni-5Co. In this case, the linear expansion coefficient of the mask substrate 110 is 2.6×10 ⁻⁶ (/°C), and the linear expansion coefficient of the support substrate 120 is 0.2×10 ⁻⁶ (/°C). In one example, the size of the pattern region PR after the processing step may be 25.4 mm×25.4 mm. In this example, the difference in the amount of expansion between the mask substrate 110 and the support substrate 120 per 1°C of temperature increase is (2.6× ^{10 −6} −0.2×10 ⁻⁶ )×1×25.4=0.00006096 mm=0.061 μm. For a deposition mask used in manufacturing an OLED panel with a pixel size of 10 μm or less, it is desirable to keep the difference in the amount of expansion to 1 μm or less, which is 10% of the pixel size. In this example, it is desirable to keep the temperature difference to 10×10 ⁻³ ×0.1÷(0.061× ^{10 −3} )=16.4°C. Therefore, if the set temperature in a general clean room is 23°C, 23±16.4°C, that is, 7 to 39°C, is a temperature suitable for the bonding process. The greater the difference between the temperature in the bonding process and the temperature after the bonding process, the greater the amount of warping of the laminate ST or deposition mask M after the bonding process, and it becomes impossible to maintain a constant distance between the pattern region PR and the wafer, or to bring them into contact with each other. Therefore, it is preferable to carry out the bonding process within a range of 7 to 39°C.

Figure 2 shows a schematic plan view of the deposition mask M manufactured by the above-mentioned manufacturing method, as viewed from the support substrate 120 side. Figure 3 shows a schematic plan view of the deposition mask M as viewed from the pattern region PR side. The deposition mask M may include a support substrate 120 having a plurality of first openings OP1 and a plurality of second openings OP2, a plurality of pattern regions PR (masks) supported by the support substrate 120, and a plurality of members 16 supported by the support substrate. Each pattern region PR (mask) may include a pattern region PR exposed through one of the plurality of first openings OP1. All or a portion of the plurality of members 16 may include an alignment mark 12 exposed through one of the plurality of second openings OP2.

Metal films 131, 132 (see FIG. 1H ) may be disposed between the support substrate 120 and the pattern region PR (mask) and between the support substrate 120 and the plurality of members 16. The support substrate 120 may be made of, for example, an alloy containing nickel and cobalt, and may have, for example, a linear expansion coefficient of 0.5×10 ⁻⁶ (/° C.) or less. The plurality of pattern regions PR (mask) may be, for example, a silicon substrate or a glass substrate.

As shown in FIG. 4, the multiple pattern regions PR (masks) are aligned with respect to a grid L defined by multiple alignment marks 12 provided on the multiple members 16. The number of the multiple members 16 is less than the number of the multiple pattern regions PR (masks).

The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

Claims (16)

a patterning step of patterning the mask substrate so that a plurality of pattern regions are formed on the mask substrate;
a bonding step of bonding the mask substrate and a support substrate to form a laminate after the patterning step ;
a processing step of processing the mask substrate so as to form separation grooves that separate the plurality of pattern regions in the laminate after the bonding step ;
A method for producing a deposition mask comprising the steps of: The bonding step is carried out without heating or cooling.
The method for producing a deposition mask according to claim 1 . The bonding step is carried out at a temperature ranging from 7° C. to 39° C.
The method for producing a deposition mask according to claim 1 . In the patterning step, a plurality of grooves are formed in the mask substrate so that no through holes are formed in the mask substrate,
a thinning step of thinning the mask substrate so that the plurality of grooves are changed into a plurality of through holes is carried out between the bonding step and the processing step;
The method for producing a deposition mask according to claim 1 . The bonding step is performed after the patterning step.
The method for producing a deposition mask according to claim 1 . The support substrate is made of an alloy containing nickel and cobalt and has a linear expansion coefficient of 0.5.
x 10 ^-6 (/°C) or less,
The method for producing a deposition mask according to claim 1 . the support substrate is made of a ceramic composite material containing amorphous silicon and titanium or crystalline silicon, and has a linear expansion coefficient of 0.5×10 ⁻⁶ (/° C.) or less;
The method for producing a deposition mask according to claim 1 . The mask substrate is a silicon substrate or a glass substrate.
The method for producing a deposition mask according to claim 1 . In the patterning step, an alignment mark is formed on the mask substrate,
In the bonding step, the mask substrate and the support substrate are aligned using the alignment mark.
The method for producing a deposition mask according to claim 1 . the supporting substrate has a plurality of first openings for exposing the plurality of pattern regions in the laminate, respectively, and a second opening for observing the alignment mark;
The method for producing a deposition mask according to claim 9 . patterning to form the plurality of pattern areas is performed on a first surface of the mask substrate;
In the bonding step, the support substrate is bonded to the first surface side of the mask substrate.
The method for producing a deposition mask according to claim 1 . In the bonding step, the first surface side of the mask substrate and the supporting substrate are bonded via a metal film.
The method for producing a deposition mask according to claim 11 . The bonding step bonds the mask substrate and the support substrate by atomic diffusion bonding.
The method for producing a deposition mask according to claim 1 . The patterning step includes:
a coating step of coating a photoresist on the mask substrate to form a photoresist film;
a transfer step of sequentially transferring a pattern of an original onto a plurality of pattern forming regions of the photoresist film using an exposure device;
a developing step of developing the photoresist film to form a resist pattern;
an etching step of forming the plurality of pattern areas by etching the mask substrate through openings in the resist pattern;
The method for producing a deposition mask according to claim 1 , further comprising: The width of the separation groove is greater than the width of the plurality of grooves.
The method for producing a deposition mask according to claim 4 . a deposition step of performing deposition on a substrate using the deposition mask manufactured by the manufacturing method according to any one of claims 1 to 13;
a processing step of processing the substrate that has been subjected to the deposition step to obtain a display device;
A method for manufacturing a display device comprising the steps of:

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