CN111254385A

CN111254385A - Metal shadow mask and method for producing the same, electroformed stencil and method for producing the same

Info

Publication number: CN111254385A
Application number: CN202010061583.4A
Authority: CN
Inventors: 潘仲光; 陈霞玲
Original assignee: Advantech Global Ltd
Current assignee: Advantech Global Ltd
Priority date: 2020-01-19
Filing date: 2020-01-19
Publication date: 2020-06-09

Abstract

The application relates to the technical field of display equipment manufacturing, in particular to an electroformed stencil, a metal shadow mask prepared on the basis of the electroformed stencil, and preparation methods of the electroformed stencil and the metal shadow mask. Wherein the metal shadow mask includes: and electroforming a metal body, wherein the electroforming metal body comprises a first deposition part and a second deposition part, the second deposition part is deposited on a part of the first deposition part in an overlapped mode, and the second deposition part is used for laser welding. The metal shadow mask can effectively reduce the shadow effect during vapor deposition and has better mesh welding strength.

Description

Metal shadow mask and method for producing the same, electroformed stencil and method for producing the same

Technical Field

The application relates to the technical field of display equipment manufacturing, in particular to an electroformed stencil, a metal shadow mask prepared on the basis of the electroformed stencil, and preparation methods of the electroformed stencil and the metal shadow mask.

Background

In the manufacturing process of an OLED (Organic Light-Emitting Diode) display screen, a Light-Emitting Organic material needs to be evaporated on a conductive glass substrate in a vacuum heating manner. For the production of an OLED display panel with high pixel density, a fine metal mask plate with a very thin thickness and a small thermal expansion coefficient is required to be used as a metal shadow mask, so that the organic light-emitting body in the pixel of the vapor deposition OLED panel meets the requirement of high resolution.

Generally, the metal shadow mask has a small thickness, is thin and brittle, and is difficult to adhere to the surface of a substrate (a glass sheet or a flexible material) on which the picture elements of the organic light emitting body are evaporated and maintain a high positional accuracy, so that the metal shadow mask is generally welded to a metal frame by a laser welding technique.

In addition, the size of the openings of the metal shadow mask determines the resolution of the OLED display screen, and the smaller the openings are, the denser the openings are, and the denser the grid points of the evaporated OLED panel is, the higher the resolution is.

However, it is generally difficult to obtain a metal shadow mask having a small thickness in the related art due to the limitation of the rolling process of the metal material. The isotropic technical characteristics of the metal material determine that the aperture size of the opening cannot be smaller than the thickness of the removed metal material, so that it is difficult to make a metal shadow mask with smaller openings based on the metal coil materials commercialized in the prior art in batches.

Meanwhile, when the opening is small, the side wall of the opening of the metal shadow mask has a shadow effect on the evaporation, and the shadow effect is increased along with the increase of the thickness of the side wall of the opening of the metal shadow mask, so that the evaporation effect is further influenced.

Disclosure of Invention

In order to solve the above-mentioned problems or at least partially solve the above-mentioned technical problems, in one embodiment of the present application, there is provided an electroformed stencil making method including the steps of:

a primary photoetching step: covering a first photosensitive film on the substrate, and forming an electroforming area by removing part of the first photosensitive film;

a primary electroforming step: immersing the substrate in an electroforming solution to deposit a metal material on the electroforming region, forming a first deposition portion;

and (3) secondary photoetching: covering a second photosensitive film on the substrate, and forming a welding area by removing part of the second photosensitive film, wherein the welding area is overlapped on a part of the first deposition part;

and (3) secondary electroforming step: the substrate is immersed in the electroforming solution, and the metal material is deposited on the welding area to form a second deposition portion.

Embodiments of the present application also provide a method for manufacturing a metal shadow mask, including the steps of the foregoing method for manufacturing an electroformed stencil, and after the secondary electroforming step, further including the steps of:

cleaning: and removing the first photosensitive film and the second photosensitive film on the prepared electroformed stencil and separating the substrate to obtain the metal shadow mask.

Embodiments of the present application also provide an electroformed stencil comprising:

a substrate;

the electroforming metal layer is covered on the substrate and comprises a first deposition part and a second deposition part, the second deposition part is deposited on a part of the first deposition part in an overlapped mode, and the second deposition part is used for laser welding;

and the photoetching film layer is filled in the area enclosed by the first deposition part and the second deposition part.

Embodiments of the present application also provide a metal shadow mask, including: and electroforming a metal body, wherein the electroforming metal body comprises a first deposition part and a second deposition part, the second deposition part is deposited on a part of the first deposition part in an overlapped mode, and the second deposition part is used for laser welding.

The embodiment of the application prepares the metal shadow mask by means of the electroforming deposition process, and compared with the traditional rolling process, the electroforming metal layer with smaller thickness can be prepared, so that the shadow effect in evaporation can be effectively reduced, and the method is more suitable for the production of the OLED display panel with high pixel density.

Meanwhile, the embodiment of the application also increases the thickness of the part, used for welding, of the metal shadow mask by means of twice electroforming, so that the ultrathin metal shadow mask still can obtain good welding strength, and the yield of products is improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are only for illustrating some embodiments of the present application, and that technical features, connections and method steps which are not mentioned in other drawings can be obtained from the drawings without creative efforts for those skilled in the art.

Fig. 1 is a schematic flow chart of a method for fabricating a metal shadow mask according to an embodiment of the present application;

FIG. 2 is a complete schematic view of an electroformed stencil (with a substrate) provided in accordance with an embodiment of the present application;

FIG. 3 is a complete schematic view of an electroformed stencil without removing the photosensitive film layer according to one embodiment of the present application;

fig. 4 is a schematic view of a metal shadow mask according to an embodiment of the present application;

FIG. 5 is a schematic view of a substrate after a photolithography step according to an embodiment of the present application;

FIG. 6 is a schematic view of a substrate after a single electroforming step according to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram illustrating a substrate with a first photosensitive film exposed after a photolithography process according to an embodiment of the present disclosure;

fig. 8 is a schematic diagram of a substrate after two photolithography steps according to an embodiment of the present application.

Description of the reference numerals

1-a substrate;

2-electroforming a metal layer; 21-a first deposition section; 22-a second deposition section;

3, photoetching a film layer; 31 — a first photosensitive film; 32-a second photosensitive film;

4-pattern open area.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Embodiments of the present application provide an electroformed stencil, a metal shadow mask fabricated based on such an electroformed stencil, and methods of fabricating both.

In the prior art, a rolling process is often used to make the metal plate or the metal film. As described above, due to the objective physical law, it is difficult to manufacture a metal shadow mask with a smaller thickness by the rolling process, and an excessively thick metal shadow mask will cause an evaporation shadow during evaporation, which greatly affects the yield of small-sized OLED cells.

Thus, the applicant of the present application has creatively adopted the means of electroforming deposition to produce a metal shadow mask of smaller thickness.

At the same time, however, the applicant of the present application has found that the difficulty of welding the metal shadow mask is further increased when the thickness of the metal shadow mask is reduced to a certain dimension. Even if welding is realized, the welding strength is poor, and the requirement of the metal shadow mask in the process of mesh expansion is difficult to meet.

In view of the above, in one embodiment of the present application, referring to fig. 1 to 8, there is provided a method for manufacturing a metal shadow mask, including the steps of:

a primary photoetching step: covering the substrate 1 with a first photosensitive film 31, and forming an electroforming region by removing a portion of the first photosensitive film 31;

a primary electroforming step: immersing the substrate 1 in an electroforming solution to deposit a metal material on the electroforming region, forming a first deposition portion 21;

and (3) secondary photoetching: covering the substrate 1 with a second photosensitive film 32, and forming a welding region by removing a portion of the second photosensitive film 32, the welding region overlapping a portion of the first deposition portion 21;

and (3) secondary electroforming step: immersing the substrate 1 in the electroforming solution to deposit a metal material on the bonding area to form a second deposition portion 22;

and after the secondary electroforming step, the method also comprises the following steps:

cleaning: the first photosensitive film 31 and the second photosensitive film 32 on the prepared electroformed stencil are removed and the substrate 1 is separated, obtaining a metal shadow mask.

On the basis of this method for manufacturing a metal shadow mask, embodiments of the present application also provide a method for manufacturing an electroformed stencil, including the steps of:

and (3) secondary photoetching: covering the substrate 1 with a second photosensitive film 32, forming a welding area by removing a portion of the second photosensitive film 32, the welding area overlapping a portion of the first deposition portion 21;

and (3) secondary electroforming step: the substrate 1 is immersed in the electroforming solution to deposit a metal material on the bonding region, thereby forming the second deposition portion 22.

And, in the embodiments of the present application, an electroformed stencil produced based on the above-described electroformed stencil producing method, and a metal shadow mask produced based on the above-described metal shadow mask producing method are proposed.

Specifically, an electroforming template, as shown in fig. 2 and 3, includes:

a substrate 1;

an electroformed metal layer 2 covering the substrate 1, the electroformed metal layer 2 including a first deposition portion 21 and a second deposition portion 22, the second deposition portion 22 being deposited on a part of the first deposition portion 21 in an overlapping manner, the second deposition portion 22 being used for laser welding;

the photoresist layer 3 is filled in a region surrounded by the first deposition portion 21 and the second deposition portion 22.

And as shown in fig. 4, a metal shadow mask, comprising: electroforming a metal body including a first deposition portion 21 and a second deposition portion 22, the second deposition portion 22 being overlappingly deposited on a part of the first deposition portion 21, the second deposition portion 22 being used for laser welding.

Wherein the electroformed stencil is an intermediate product of a process for making a metallic shadow mask. Through the cleaning step, a complete metal shadow mask can be obtained from the electroformed stencil.

Accordingly, in the embodiments of the present application, a specific process for fabricating a metal shadow mask is given as follows:

1. a first photosensitive film 31 is covered on the substrate 1. Specifically, in the photolithography process, the first photosensitive film 31 made of a plastic material may be pressed on the clean substrate 1 by a heated laminator. The first photosensitive film 31 mainly plays a role in blocking during electroforming, and can prevent metal deposition from occurring in the region covered by the photosensitive film.

2. Referring to fig. 5, a removing operation is performed on the first photosensitive film 31. Specifically, a portion to be removed may be exposed by an exposure machine, and then the first photosensitive film 31 of the exposed portion may be removed by a developing solution to obtain a desired pattern shape.

3. The substrate 1 is immersed in an electroforming solution to deposit a metal material on the electroforming region. For example, the nickel-iron alloy may be used as an anode, and after a certain current is applied, the nickel-iron alloy may be deposited on the substrate 1 by utilizing the principle of electrodeposition. Of course, other types of metals may be deposited as desired. In one electroforming step, as shown in fig. 6, the deposited metal will form the first deposition portion 21. At this time, since the region covered by the photosensitive film is not deposited with the metal material, the pattern opening region 4 is formed. And, as shown in fig. 7, if the remaining first photosensitive film 31 is removed, a single-layer deposited metal shadow mask having pattern opening regions 4 can be obtained. During the subsequent evaporation, the pattern opening regions 4 will be used for the passage of organic evaporation gas to adhere to the substrate covered by the metal shadow mask.

4. And entering a secondary photoetching step, and continuing to cover the substrate 1 with a second layer of photosensitive film, so that the second layer of photosensitive film is covered on the first layer of photosensitive film and the first deposition part 21. Then, further, a removing operation is performed on the second photosensitive film 32. Referring to fig. 8, the removed area may be the welded area of the final metal mask during the mesh welding. Wherein this overlaps a portion of the first deposition portion 21.

5. Referring to fig. 3, the deposition process is continued on the substrate 1 subjected to the second photolithography, and a second deposition portion 22 deposited on a portion of the first deposition portion 21 can be obtained. In this way, the sum of the thicknesses of the first deposition portion 21 and the second deposition portion 22 is thicker than that of the single first deposition portion 21, so that the welding strength can be remarkably improved, the welding difficulty can be reduced, and the welding quality can be improved. After this step is completed, an electroformed stencil is obtained that includes a complete metallic shadow mask.

6. Referring to fig. 4, this metal shadow mask is obtained after completely removing the first photosensitive film 31 and the second photosensitive film 32 on the prepared electroformed stencil and separating the substrate 1. The obtained metal shadow mask can be applied to a subsequent organic evaporation process after the expanded mesh welding.

In the embodiment of the present application, the process sequence of first forming the first deposition portion 21 for vapor deposition and then overlapping the second deposition portion 22 for soldering on the first deposition portion 21 is adopted, which is advantageous over the process sequence of first forming the deposition portion for soldering and then forming the remaining deposition portions for vapor deposition on the deposition portion.

Specifically, if a deposition site for soldering is first formed and then the remaining deposition sites for evaporation are formed on the deposition site, the size of the contact surface between the two deposition sites is limited by the thickness of the deposition site for evaporation, the bonding force is small, the strengthening effect of the soldering force is hard to be achieved, and even breakage may occur. When the first deposition portion 21 is formed first and then the second deposition portion 22 is overlapped on the first deposition portion 21, the contact area between the first deposition portion 21 and the second deposition portion 22 is larger and the bonding force is stronger. It is worth mentioning that in the various diagrams of the figures, the length ratios in the various directions have been changed for the sake of clarity of illustration. In actual production, the thickness of the metal shadow mask and the various film layers are typically within 100 microns and are quite thin, as explained herein.

The inventors of the present application have found that the sidewall thickness of the patterned open region 4, i.e. the thickness of the first deposition portion 21, is directly related to the quality of organic evaporation. Specifically, if the thickness of the first deposition portion 21 is too thick, the organic material deposited in the pattern opening region 4 is significantly less than that in the central portion, and a vapor deposition shadow is generated, resulting in defects. Thus, optionally, the thickness of the metal material deposited in one electroforming step is less than or equal to 10 microns. That is, the thickness of the first deposition portion 21 is less than or equal to 10 μm.

The inventors of the present application have found that when the thickness of the first deposition portion 21 is 10 μm or less, particularly, between 3 and 7 μm, the evaporation effect can be better ensured. Moreover, this thickness level can only be reached when the solution of the present application is applied. If the deposition site for soldering is first fabricated and then the rest deposition sites for vapor deposition are fabricated on the deposition site, it is difficult to achieve the thickness level due to the limitation of the contact area.

Meanwhile, since the thickness of the first deposition portion 21 is small, the deposition thickness of the metal material may be greater than or equal to 10 μm in the secondary electroforming step in order to secure the soldering quality. In particular, the sum of the thicknesses of the first deposition portion 21 and the second deposition portion 22 may be greater than or equal to 20 micrometers.

The thickness of 20 microns or more is close to the limit thickness of the metal coil in the rolling process in the prior art, thereby meeting the thickness requirement of the welding part of the metal shadow mask in the laser welding process in the prior art.

Further, optionally, in the secondary photolithography step, the soldering region is located at the edge of the substrate 1.

Optionally, the photoresist layer 3 includes:

a first photosensitive film 31 filled in a region surrounded by the first deposition portion 21;

the second photosensitive film 32 fills the region surrounded by the second deposition portion 22.

In summary, the embodiment of the present invention prepares the metal shadow mask by using the electroforming deposition process, and compared with the conventional rolling process, the electroforming metal layer 2 with smaller thickness can be prepared, so that the shadow effect during evaporation can be effectively reduced, and the method is more suitable for the production of the OLED display panel with high pixel density.

It is to be understood that the terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only, and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a" and "an" typically include at least two, but do not exclude the presence of at least one.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present application to describe certain components, these components should not be limited by these terms. These terms are only used to distinguish one component from another. For example, a first certain component may also be referred to as a second certain component, and similarly, a second certain component may also be referred to as a first certain component without departing from the scope of embodiments herein.

The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a monitoring", depending on the context. Similarly, the phrase "if it is determined" or "if it is monitored (a stated condition or event)" may be interpreted as "when determining" or "in response to determining" or "when monitoring (a stated condition or event)" or "in response to monitoring (a stated condition or event)", depending on the context.

In the embodiments of the present application, "substantially equal to", "substantially perpendicular", "substantially symmetrical", and the like mean that the macroscopic size or relative positional relationship between the two features referred to is very close to the stated relationship. However, it is clear to those skilled in the art that the positional relationship of the object is difficult to be exactly constrained at small scale or even at microscopic angles due to the existence of objective factors such as errors, tolerances, etc. Therefore, even if a slight point error exists in the size and position relationship between the two, the technical effect of the present application is not greatly affected.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

In the various embodiments described above, while, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated by those of ordinary skill in the art that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein or not shown and described herein, as would be understood by one of ordinary skill in the art.

Finally, it should be noted that those skilled in the art will appreciate that embodiments of the present application present many technical details for the purpose of enabling the reader to better understand the present application. However, the technical solutions claimed in the claims of the present application can be basically implemented without these technical details and various changes and modifications based on the above-described embodiments. Accordingly, in actual practice, various changes in form and detail may be made to the above-described embodiments without departing from the spirit and scope of the present application.

Claims

1. A method for preparing an electroformed stencil, comprising the steps of:

a primary photoetching step: covering a first photosensitive film on a substrate, and forming an electroforming area by removing part of the first photosensitive film;

and (3) secondary electroforming step: and immersing the substrate into an electroforming solution, and depositing a metal material on the welding area to form a second deposition part.

2. The electroformed stencil preparation method as claimed in claim 1, wherein the deposition thickness of the metallic material in the one electroforming step is 10 μm or less.

3. The electroformed stencil preparation method of claim 1, wherein in the secondary electroforming step, the deposition thickness of the metallic material is greater than or equal to 10 microns.

4. The method of claim 1, wherein in the secondary photolithography step, the solder region is located at an edge of the substrate.

5. A method for producing a metal shadow mask, characterized by comprising the steps of the method for producing an electroformed stencil as claimed in any one of claims 1 to 4, and further comprising, after the secondary electroforming step, the steps of:

6. An electroformed stencil, comprising:

a substrate;

and the photoetching film layer is filled in a region enclosed by the first deposition part and the second deposition part.

7. The electroformed stencil of claim 6, wherein the photolithographic film layer comprises:

a first photosensitive film filled in the region surrounded by the first deposition portion;

and the second photosensitive film is filled in the area enclosed by the second deposition part.

8. The electroformed stencil of claim 6, wherein the thickness of the first deposited portion is less than or equal to 10 microns.

9. The electroformed stencil of claim 6, wherein the sum of the thicknesses of the first and second deposits is greater than or equal to 20 microns.

10. A metal shadow mask, comprising: an electroformed metal body including a first deposition portion and a second deposition portion that is overlappingly deposited on a portion of the first deposition portion, the second deposition portion being for laser welding.