CN115961314A - Preparation method of composite mask - Google Patents

Abstract

A preparation method of a composite mask comprises the following steps: s1: a photoetching pattern is arranged on the mask plate; s2: removing part of the photoresist through a photoetching pattern; s3: electroforming a mask plate, and uniformly coating a polymer film layer on the mask plate; s4: curing and molding the polymer film layer; s5: pulse drilling is carried out on the solidified polymer film layer, a cone-like truncated cone hole with a cone angle is formed, the diameter of an inlet of the hole is larger than that of an outlet of the hole, and the range of the cone angle is controlled to be 30-120 degrees; s6: removing the residual photoresist by using a cleaning solution; s7: and cleaning the laser opening residues, and drying the mask to finish the preparation. According to the invention, a layer of polymer low-thermal expansion coefficient material attached to metal is added on the electroforming mask plate, so that the thermal expansion of the electroforming mask plate is effectively weakened, and the through hole with a certain taper angle is formed under the action of the femtosecond laser, so that the difficulty that the taper angle is difficult to control effectively when the thickness is pursued by electroforming is solved.

Description

A kind of preparation method of composite mask plate

technical field

The invention relates to the field of electronic equipment processing, in particular to a method for preparing a composite mask.

Background technique

FMM (fine metal mask, precision mask plate) is the key fixture for preparing OLED devices. Metals or alloys with low expansion coefficients are often used as substrates. At present, the mainstream FMM production technology is divided into two types, one is etching, and the other is electroforming.

The disadvantage of using the etching method is that the etching effect of the etching solution is isotropic, and the opening size is close to the thickness. In addition, the thickness of the Invar alloy used for etching is about 30um, so the opening size is relatively large, and the goal of high PPI cannot be achieved.

The electroforming method can effectively control the thickness of the mask. , due to the difficulty of electroforming binary alloys, most manufacturers use single magnetic metals such as Ni as the base material. However, the thermal expansion coefficient of Ni itself reaches 1.3*10 ^-5 /K, which is far from meeting the requirement of low thermal expansion coefficient (3*10 ^-6 /K) for OLED evaporation. Moreover, it is difficult to control the Taper angle while controlling the thickness of the substrate by electroforming.

Therefore, the current electroforming process is difficult to meet the requirements of OLED evaporation, and a new mask preparation method is urgently needed.

Contents of the invention

The purpose of the present invention is to effectively overcome the thermal expansion caused by the electroformed substrate and the difficulties of precisely controlling the opening angle in the mask plate preparation process.

Therefore, a method for preparing a composite mask is proposed, and the specific technical scheme is as follows:

A method for preparing a composite mask, characterized in that:

Including the following steps:

S1: a photolithography pattern is set on the mask;

S2: removing part of the photoresist through the photolithography pattern;

S3: Electroformed mask plate, evenly coating polymer film on the mask plate;

S4: curing the polymer film layer;

S5: Perform pulse drilling on the cured polymer film, and open a frustum-like hole with a cone angle. The entrance of the hole is larger than the exit aperture, and the cone angle is controlled within 30°-120°;

S6: removing the remaining photoresist with a cleaning solution;

S7: cleaning the laser opening residue, drying the mask, and completing the preparation.

For realizing the present invention better, can further:

In S4, the polymer film layer is cured and formed by laser heat treatment or baking.

Further: the polymer is made of a material with a low thermal expansion coefficient, and the material of the polymer film layer is selected from polyimide, polypropylene, polyethylene terephthalate or graphene.

Further: in said S5, drilling is performed by using femtosecond laser pulses of a Yb:KGW femtosecond laser.

Further: the parameter that described Yb:KGW femtosecond laser adopts is, center wavelength 1024nm, average power 6W, pulse duration 190fs, pulse repetition frequency Yb:KGW femtosecond laser rate 200KHz, pulse maximum energy 1mJ, by transforming pulse amplitude 1um-100um to adjust the taper angle, the taper angle is the taper angle.

Further: the inlet diameter of the hole is 1-40um.

Further: the thickness of the polymer film layer is controlled between 5um-100um.

Further: the cleaning solution uses hydrofluoroether.

Further: the polymer film layer adopts polyimide.

Further: the mask uses Ni, Fe, Co.

The beneficial effects of the present invention are:

First, the present invention adds a layer of high molecular low thermal expansion coefficient material bonded to the metal on the electroformed mask, which can effectively weaken the thermal expansion of the electroformed mask due to the increased adhesion of the layer, and solves the problem of electroforming. Thermal expansion of cast mask.

Second, the invention performs alignment laser opening on the increased material layer, and opens a through hole with a certain taper angle through the action of femtosecond laser, which solves the problem that it is difficult to effectively control the taper angle during the thinning process of electroforming difficulty.

Description of drawings

Fig. 1 is the concrete flow chart of work of the present invention;

Figure 2 is a schematic diagram of photoresist coating;

Figure 3 is a schematic diagram of making holes;

Figure 4 is a schematic diagram of hole completion;

Figure 5 schematic diagram of electroforming;

Figure 6 is a schematic diagram of the completion of electroforming;

Fig. 7 is coated with polymer layer schematic diagram;

Figure 8 is a schematic diagram of the connection between polymers and metals;

Figure 9 schematic diagram of laser opening;

Figure 10 is a schematic diagram after the opening is completed;

The drawings in the figure are illustrated as cathode plate 1, photoresist 2, UV light 3, mask 4, electroplating solution 5, metal block 6, anode plate 7, polymer film 8, and laser 9.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Figure 1:

A method for preparing a composite mask, comprising the steps of:

S1: As shown in Figure 2, a photoresist is provided on the cathode plate, and the thickness of the photoresist is 3-30um.

S2: As shown in Fig. 3 and Fig. 4, a mask hole pattern is arranged on the surface of the photoresist, and the excess photoresist is removed by UV light irradiation and development;

S3: As shown in FIG. 5 , an anode plate is arranged opposite to the cathode plate, and an electroplating solution is arranged between the cathode plate and the anode plate to obtain an electroformed metal layer. As shown in FIG. 6, the thickness of the electroformed metal layer is consistent with the thickness of the photoresist. In this embodiment, the metal layer is Ni. The metal layer can also use Fe, Co or a combination with other elements;

S4: As shown in FIG. 7 , uniformly coat a polymer film layer on the surface of the metal layer and the photoresist layer, and control the thickness of the polymer film layer between 3-50 um. The polymer adopts a material with a low thermal expansion coefficient, and the material of the polymer film layer is selected from polyimide, polypropylene, polyethylene terephthalate or graphene.

The polymer film layer is cured and formed, specifically, the polymer film layer is cured and formed by laser heat treatment or baking.

S5: As shown in FIG. 8 , remove the cathode plate and the photoresist to obtain a polymer film layer with a metal block on the lower surface.

S6: As shown in Figure 9, a Yb:KGW femtosecond laser is used to perform pulse drilling on the cured polymer film layer through a femtosecond laser pulse, and a frustum-like hole with a cone angle is opened. The entrance of the hole is larger than the exit. The pore diameter is large, the inlet size of the pore diameter is 1-40um, and the cone angle range is controlled at 30°-120°. The specific structure is shown in Figure 10.

The central wavelength of the femtosecond laser is 1024nm, the average power is 6W, the pulse duration is 190fs, the pulse repetition frequency is 200KHz, the maximum pulse energy is 1mJ, and the taper angle is adjusted by changing the pulse amplitude from 1um to 100um.

S7: Cleaning with hydrofluoroether, laser opening remains, and drying, complete.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (10)

1. A preparation method for a composite mask, characterized in that: Including the following steps: S1: a photolithography pattern is set on the mask; S2: removing part of the photoresist through the photolithography pattern; S3: Electroformed mask plate, evenly coating polymer film on the mask plate; S4: curing the polymer film layer; S5: Perform pulse drilling on the cured polymer film, and open a frustum-like hole with a cone angle. The entrance of the hole is larger than the exit aperture, and the cone angle is controlled within 30°-120°; S6: removing the remaining photoresist with a cleaning solution; S7: cleaning the laser opening residue, drying the mask, and completing the preparation. 2. the preparation method of a kind of composite mask according to claim 1, is characterized in that: In S4, the polymer film layer is cured and formed by laser heat treatment or baking. 3. according to the preparation method of a kind of composite mask plate described in claim 2, it is characterized in that: described macromolecule adopts low thermal expansion coefficient material, and the material of described macromolecule film layer selects polyimide, polypropylene, polypropylene for use. Ethylene terephthalate or graphene. 4. the preparation method of a kind of composite mask according to claim 3, is characterized in that: In said S5, drilling is performed by using femtosecond laser pulses of a Yb:KGW femtosecond laser. 5. the preparation method of a kind of composite mask plate according to claim 4 is characterized in that: the parameter that described Yb:KGW femtosecond laser adopts is, central wavelength 1024nm, average power 6W, pulse duration 190fs, pulse repetition Frequency Yb: The rate of KGW femtosecond laser is 200KHz, the maximum pulse energy is 1mJ, and the taper angle is adjusted by changing the pulse amplitude from 1um to 100um. 6 . The method for preparing a composite mask according to claim 5 , characterized in that: the entrance diameter of the hole is 1-40 um. 7. A method for preparing a composite mask according to claim 6, characterized in that: the thickness of the polymer film layer is controlled between 5um-100um. 8 . The method for preparing a composite mask according to claim 7 , wherein the cleaning solution is hydrofluoroether. 9 . The method for preparing a composite mask according to claim 8 , wherein the polymer film layer is made of polyimide. 10 . The method for preparing a composite mask according to claim 9 , wherein the mask is made of Ni, Fe, Co. 11 .

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