Electrostatic adsorption mask plate and manufacturing method and manufacturing system of electrostatic adsorption mask plate

Abstract

The invention discloses an electrostatic adsorption mask plate, and a manufacturing method and a manufacturing system of the electrostatic adsorption mask plate. The electrostatic adsorption mask plate comprises a substrate, the substrate is provided with a plurality of openings, and the openings correspond to mask pattern areas of the mask plate; the insulating isolation layer is positioned on the first surface of the substrate, is laminated with the substrate and is provided with a mask pattern; the mask pattern comprises a through hole with a trapezoidal cross section; the electrostatic adsorption conductive layer is arranged on the insulation isolation layer and is used for obtaining electrostatic charges from an external electrostatic generator; and the electrostatic shielding conductive layer covers the second surface of the substrate, the surface of the insulating isolation layer at the opening and the side wall of the through hole, and is grounded. The electrostatic adsorption mask plate provided by the invention not only has good mechanical performance and low thermal deformation, but also can enable a power line to only terminate between the electrostatic shielding conductive layer and the substrate, so that the power line cannot influence the molecular trajectory of a vapor deposition material, thereby improving the film deposition quality and reducing the hole blocking risk.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to an electrostatic adsorption mask, a method for manufacturing an electrostatic adsorption mask, and a manufacturing system. Background Art

[0002] Vapor deposition technology includes various physical and chemical vapor deposition methods such as thermal evaporation vacuum vapor deposition, magnetron sputtering, molecular beam deposition, chemical vapor deposition and atomic layer deposition. In many fields, including semiconductor and display manufacturing, it is necessary to vapor-deposit a thin film with a specific pattern on a certain substrate. The mask vapor deposition method is to use a film or thin plate with a specific arrangement of holes to block the thin film deposition surface of the substrate during the vapor deposition of the substrate, so that the area blocked by the film or thin plate cannot be deposited with a film, and the film is only deposited in the hole area. This film or thin plate device used to selectively deposit a film on the substrate during the film deposition process is generally called a mask or mask. With the development of high-PPI OLEDOS devices, the development of high-PPI fine masks has become the main research direction of many OLED panels and upstream and downstream manufacturers. In order to improve the accuracy of the pattern, the mask used to make high-precision patterns needs to meet many demanding conditions, mainly including: 1. Very small shadow effect; 2. Appropriate thermal expansion coefficient; 3. Low production, use and cleaning costs.

[0003] Due to the different movement directions of the vapor deposition materials, the edge of the mask away from the substrate will selectively block the vapor phase material, making the thickness of the deposited patterned film uneven, especially the thickness of the edge gradually decreases, resulting in shadows. For fine masks with very small mask patterns, in order to reduce the shadow effect, the thickness of the mask must be very small, which causes the mask to sag significantly under the action of gravity, resulting in a larger gap between the mask and the substrate, which in turn intensifies the shadow effect and reduces the quality of the thin film deposition pattern.

[0004] During the physical and chemical vapor deposition of thin films on a certain substrate, the collision and chemical reaction between the vapor phase material and the substrate surface will cause the substrate and mask to heat up. Some vapor deposition substrates are materials with very low thermal expansion coefficients, such as silicon and glass. The thermal expansion coefficient of silicon is α = 3×10 -6 / K, thermal expansion coefficient of glass α = 7 × 10 -6 / K, at this time, the thermal expansion coefficient is generally 10-20×10 -6 The thermal expansion coefficient of metals between 100 and 200 × 10 -6Materials with too large thermal expansion coefficients, such as polymers with a thermal expansion coefficient between 100 μm and 1 μm, cannot usually be used. This is because for masks that need to produce fine patterns with a size of less than 100 μm or even 1 μm or below, the mismatch in thermal expansion between the mask and the substrate will cause the mask to deform, reduce the quality of the thin film pattern, and cause damage to the mask.

[0005] The materials currently used to make high-precision vapor deposition masks are mainly silicon nitride and Invar alloy, and their thickness is generally only 1-5μm, which makes them very fragile and easily damaged during manufacturing, storage, transportation, use and cleaning, and cannot be used any longer.

[0006] In the prior art, in order to solve the above defects of the traditional fine mask, Liu Chengyuan et al. invented an electrostatic adsorption mask (China Patent Publication No.: CN117385323A). This mask uses a low thermal expansion coefficient of α = 1-3×10 -6 The skeleton made of dielectric materials such as glass or polymer with a thickness of 1000K / K is used as the pattern definition layer for vapor deposition. In order to eliminate the droop of the dielectric material, a conductive layer is deposited or pasted on its surface, and an electrostatic generator is used to make the conductive layer statically charged. The pattern definition layer is closely attached to the surface of the substrate through the electrostatic adsorption between the conductive layer and the substrate. Although the problems of low thermal expansion coefficient, low gravity droop and low damage rate of the mask are solved, a bigger problem is introduced at the same time: electrostatic adsorption has an attractive or repulsive interaction on all charged substances, including conductors, semiconductors, insulators and plasma in solid, liquid and gaseous states. Therefore, although the electrostatic adsorption mask is closely attached to the substrate through electrostatic adsorption, reducing gravity droop, it will also have an effect on the molecules, atoms, ions and atomic groups deposited in the vapor phase, and even adsorb them in large quantities on the edge surface of the electrostatic adsorption conductive layer, resulting in pore blocking and difficulty in deposition on the substrate. This disadvantage is particularly obvious for molecules with large molecular weight and strong induction force and polar molecules.

[0007] Meanwhile, in the prior art, in order to form a specific cross-sectional shape during the etching process, multiple experiments are often required to determine the parameters such as the concentration and flow rate of the etchant required for etching the specific shape, and the steps are complicated. The prior art is still unable to solve the above problems. Summary of the invention

[0008] In order to solve the problems existing in the prior art, the present invention provides an electrostatic adsorption mask, a method for manufacturing the electrostatic adsorption mask and a manufacturing system.

[0009] The present invention provides an electrostatic adsorption mask, comprising: a substrate, the substrate having a plurality of openings, the openings corresponding to the mask pattern area of ​​the mask; an insulating isolation layer with a mask pattern located on the first surface of the substrate and the substrate stack, the mask pattern comprising a through hole with a trapezoidal cross-section; an electrostatic adsorption conductive layer, arranged on the insulating isolation layer, for obtaining static charge from an external electrostatic generator; an electrostatic shielding conductive layer, covering the second surface of the substrate and the surface of the insulating isolation layer at the opening and the side wall of the through hole, and being grounded; wherein the second surface of the substrate is opposite to the first surface of the substrate.

[0010] Optionally, the electrostatic adsorption mask further includes: an insulating isolation layer located on the second surface of the substrate.

[0011] Optionally, the material of the insulating isolation layer is silicon dioxide.

[0012] Optionally, the through hole has a shape of a quadrilateral, a hexagon, an octagon, and a combination thereof.

[0013] Optionally, the electrostatic adsorption conductive layer is made of a conductor or a semiconductor.

[0014] Optionally, the electrostatic shielding conductive layer is made of a conductor or a semiconductor.

[0015] The present invention also provides a method for manufacturing an electrostatic adsorption mask template, comprising: providing a substrate; forming an insulating isolation layer on the first surface of the substrate; forming a patterned electrostatic adsorption conductive layer on the insulating isolation layer; etching the insulating isolation layer using a dry etching process to form a through hole with a trapezoidal cross-section, the dry etching process comprising: placing the substrate on a sample stage of a dry etching machine for n etchings, rotating the sample stage in the same direction around the vertical center axis of the sample stage by α° after each etching, the sample stage being arranged in the dry etching machine at an angle k inclined to the horizontal direction of the dry etching machine, wherein the range of α is 0-180°, n*α°=360°, and the range of k is 0-90°; etching the substrate from the second surface of the substrate to form a plurality of openings, the openings corresponding to the mask pattern area of ​​the mask template; forming an electrostatic shielding conductive layer on one side of the second surface of the substrate, the second surface of the substrate being opposite to the first surface of the substrate.

[0016] Optionally, the method for manufacturing the electrostatic adsorption mask further includes: after providing a substrate, forming an insulating isolation layer on a second surface of the substrate; and etching the insulating isolation layer on the second surface of the substrate to expose the substrate in a mask pattern area.

[0017] Optionally, the material of the insulating isolation layer is silicon dioxide.

[0018] Optionally, the substrate is a silicon wafer.

[0019] Optionally, the through hole has a shape of a quadrilateral, a hexagon, an octagon, and a combination thereof.

[0020] Optionally, the electrostatic adsorption conductive layer is made of a conductor or a semiconductor.

[0021] Optionally, the electrostatic shielding conductive layer is made of a conductor or a semiconductor.

[0022] The present invention also provides a system for making an electrostatic adsorption mask template, comprising: a deposition unit, used to form an insulating isolation layer on the first surface of a substrate, and to form a patterned electrostatic adsorption conductive layer on the insulating isolation layer; an etching unit, used to perform multiple etchings on the insulating isolation layer on the first surface of the substrate placed on a sample stage of a dry etching machine in a dry etching process step to form a through hole with a trapezoidal cross-section; an angle control unit, used to perform n etchings in the dry etching process step, and after each etching, the sample stage is rotated α° in the same direction around the vertical center axis of the sample stage, and the sample stage is arranged in the dry etching machine at an angle k inclined to the horizontal direction of the dry etching machine, wherein the range of α is 0-180°, n*α°=360°, and the range of k is 0-90°; the etching unit is also used to etch the substrate from the second surface of the substrate to form a plurality of openings, and the openings correspond to the mask pattern area of ​​the mask template; the deposition unit is also used to form an electrostatic shielding conductive layer from one side of the second surface of the substrate, and the second surface of the substrate is opposite to the first surface of the substrate.

[0023] Optionally, the deposition unit is further used to form an insulating isolation layer on the second surface of the substrate.

[0024] Optionally, the etching unit is further used to etch the insulating isolation layer on the second surface of the substrate to expose the substrate in the mask pattern area.

[0025] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0026] The present invention provides an electrostatic adsorption mask, a method for making an electrostatic adsorption mask, and a system for making an electrostatic adsorption mask. Through multiple tilted dry etching processes, a trapezoidal cross-section through hole with an arbitrary tilt angle is formed in the mask pattern of the electrostatic adsorption mask, which brings good mechanical properties and low thermal deformation to the electrostatic adsorption mask. At the same time, the electrostatic adsorption mask introduces a structure for electrostatic shielding, which effectively shields the electric lines generated during the use of the electrostatic adsorption mask by surrounding the electrostatic shielding conductive layer outside the electrostatic adsorption conductive layer of the electrostatic adsorption mask, and grounding the electrostatic shielding conductive layer, so that the electric lines can only terminate between the electrostatic shielding conductive layer and the substrate, without any leakage, and will not affect the deposition of polar gaseous materials on the substrate, thereby increasing the quality of thin film deposition, reducing the risk of hole blocking, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic diagram of the working principle of an electrostatic adsorption mask without an electrostatic shielding structure in the prior art;

[0029] Figure 2 A schematic diagram of a process of manufacturing an electrostatic adsorption mask according to an embodiment of the present disclosure;

[0030] Figure 3a-3h A schematic diagram of an intermediate structure of a process for forming an electrostatic adsorption mask according to an embodiment of the present disclosure;

[0031] Figure 4 It is a structural schematic diagram of a dry etching machine used for etching an insulating isolation layer in a method for manufacturing an electrostatic adsorption mask according to an embodiment of the present disclosure;

[0032] Figure 5 A schematic diagram of a process of forming a through hole with a trapezoidal cross section by multiple inclined etchings in an embodiment of the present disclosure;

[0033] Figure 6 An example of a schematic diagram of a cross-sectional shape of an electrostatic adsorption mask, which is an example of a schematic diagram of a top view structure of a substrate with a patterned insulating isolation layer in an embodiment of the present disclosure;

[0034] Figure 7 The cross-sectional structure diagram of the electrostatic adsorption mask according to the embodiment of the present disclosure is given as an example. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0036] In the present invention, unless otherwise specified, the directional words used, such as "upper and lower", generally refer to the upper and lower parts of the device in normal use, and "inside and outside" refer to the outline of the device. In addition, the terms "first, second, third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first, second, third" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In the present invention, it is an electrical device, so connection and interconnection both refer to conductive interconnection. Since the accompanying drawings are descriptions of the same device, the same numbers in the drawings represent the same components.

[0037] As described in the background technology, in the prior art, electrostatic adsorption is used to keep the fine mask close to the substrate during the vapor deposition process, but this will also cause gaseous molecules, atoms or ions to change their trajectories due to the electrostatic effect of the mask. There is a high probability that gaseous molecules will be adsorbed on the sides and surface of the mask, causing problems such as pore blockage and ineffective film coating.

[0038] In the prior art, the process of vapor-depositing organic materials on a silicon-based OLED device by vacuum thermal evaporation under the cover of a mask is taken as an example. Figure 1 As shown, 105 in the figure is the substrate for vapor deposition, that is, the target for the vapor deposition material to be deposited. The anode 106 is generally a transparent indium tin oxide conductive film. 300 represents an organic or inorganic insulating material, which is used to isolate the anode to prevent electrostatic induction between anodes and electrical crosstalk between pixels. 100 represents the skeleton of the electrostatic adsorption mask, which has a series of through holes running through both sides. The vapor deposition material can be deposited on a specific area on the surface of the substrate through these through holes, so that a functional layer with a specific pattern can be deposited on the surface of the substrate. Therefore, this layer of dielectric material is called a pattern definition layer. The electrostatic adsorption conductive layer 101 is connected to an electrostatic generator through an insulated wire, and the surface can carry positive and negative and numerically adjustable electrostatic charges. By adjusting the amount of electrostatic charge, the electrostatic adsorption conductive layer 101 can make the electrostatic adsorption mask plate at 0-75N / cm 2 The adjustable force is uniformly adsorbed on the substrate. The dotted line 104 in the figure represents the electric lines of the electrostatic field. For polar molecules 107, the movement in the non-uniform electric field will be affected by the electric field, change the movement trajectory, and even be adsorbed on the surface of the conductive layer, causing uneven coating or even blocking of holes.

[0039] Therefore, the embodiments of the present disclosure provide an electrostatic adsorption mask, a method for manufacturing an electrostatic adsorption mask, and a manufacturing system, which can form an electrostatic adsorption mask with excellent mechanical properties and low thermal deformation, so that the electric lines can only terminate between the electrostatic shielding conductive layer and the substrate, and will not affect the deposition of polar gaseous materials on the substrate.

[0040] An embodiment of the present disclosure provides an electrostatic adsorption mask, comprising: a substrate having a plurality of openings, wherein the openings correspond to mask pattern areas of the mask; an insulating isolation layer having a mask pattern disposed between the first surface of the substrate and the substrate stack, wherein the mask pattern comprises a through hole with a trapezoidal cross-section; an electrostatic adsorption conductive layer disposed on the insulating isolation layer for obtaining static charge from an external electrostatic generator; an electrostatic shielding conductive layer covering the second surface of the substrate, the surface of the insulating isolation layer at the openings, and the side walls of the through hole, and being grounded; wherein the second surface of the substrate is opposite to the first surface of the substrate.

[0041] The specific examples of the present invention are further described in detail below in conjunction with the accompanying drawings. Among them, the substances not listed in detail in the embodiments can be selected from any substances on the market that can achieve corresponding functions, such as the degumming liquid can be selected from any degumming liquid on the market that can remove the corresponding ultraviolet glue.

[0042] This embodiment also provides a method for making an electrostatic adsorption mask, the specific steps are as follows: Figure 2 As shown, Figure 3a-3h The figure shows an intermediate structure diagram of a process of forming an electrostatic adsorption mask according to an embodiment of the present disclosure. Figure 2 and Figure 3a-3h The method for making the electrostatic adsorption mask comprises the following steps:

[0043] S1: Provide a substrate.

[0044] Specifically, a substrate 110 is provided, which is used as a skeleton and an isolation layer of the electrostatic adsorption mask. In some embodiments, the substrate is any one or a combination of glass, silicon nitride, and diamond. In this embodiment, the substrate is a single-sided polished silicon (Si) wafer with a diameter of 300 mm and a thickness of 315 μm.

[0045] S2: forming an insulating isolation layer on the first surface of the substrate.

[0046] First, the substrate 110 is placed in a megasonic cleaning machine, and is cleaned with deionized water, acetone, and isopropyl alcohol for 30 minutes each, and then blown dry with ultrapure nitrogen. Then, the cleaned and dried substrate 110 is placed in a tube furnace and heated to 1000°C in a vacuum environment, and wet O2 (95°C H2O) is introduced for oxidation for about 60 minutes, so that the insulating isolation layer 100 is formed on the first surface and the second surface of the substrate 110 at the same time, as shown in FIG. Figure 3a The insulating isolation layer 100 is made of silicon dioxide (SiO2), and then the oxygen is stopped and the vacuum is evacuated, and the temperature is gradually reduced to room temperature.

[0047] In some embodiments, the thickness of the insulating isolation layer is 0.1-10 μm, preferably 0.5-5 μm. In this embodiment, the thickness of the insulating isolation layer 100 is 0.8 μm.

[0048] In the disclosed embodiment, the method for manufacturing the electrostatic adsorption mask template also includes: etching the insulating isolation layer on the second surface of the substrate to expose the substrate in the mask pattern area. Specifically, the substrate 110 having the insulating isolation layer 100 on the first surface and the second surface is taken out of the tube furnace, and a photoresist is first spin-coated on the second surface of the substrate 110, exposed through the mask template, dried and developed to produce a patterned photoresist. Thereafter, the photoresist is spin-coated on the entire surface of the first surface of the substrate 110 and then dried at a temperature of 205°C so that the photoresist covers and protects the entire first surface of the substrate 110. Then, the substrate 110 is placed in a wet etcher, immersed in a 10:1 BOE solution, and etched for 5 minutes to remove the insulating isolation layer 100 on the second surface of the substrate 110 that is not protected by the patterned photoresist, refer to Figure 3b , a patterned insulating isolation layer 100 is obtained on the second surface of the substrate 100. The 10:1 BOE solution is composed of a 40% NH4F aqueous solution and a 49% HF aqueous solution mixed in a volume ratio of 10:1. Then rinse with deionized water again for 10 minutes. After rinsing, heat the piranha etching solution to 120°C for 10 minutes to remove the photoresist on the surface of the insulating isolation layer 100 on the substrate 110, wherein the piranha etching solution is a 10:1 mixture of sulfuric acid and hydrogen peroxide. Rinse with deionized water for another 10 minutes, then immerse the substrate 110 in isopropyl alcohol (IPA) and slowly pull it out so that it dries immediately when it leaves the solution to prevent drying marks and debris.

[0049] S3: forming a patterned electrostatic adsorption conductive layer on the insulating isolation layer.

[0050] In the embodiment of the present disclosure, the substrate 110 with the insulating isolation layer 100 formed on the surface is transferred to a physical vapor deposition (PVD) device, and an electrostatically adsorbed conductive layer 101 is formed on the insulating isolation layer 100 on the first surface of the substrate 110 by magnetron sputtering. Figure 3cAs shown, the electrostatically adsorbed conductive layer 101 is a copper (Cu) / chromium (Cr) / nickel (Ni) composite film. Among them, the Cu film thickness is 20nm, the Cr film thickness is 300-500nm, and the Ni film thickness is 20nm. Cu is soft in texture and can prevent the Cr layer from falling off from the surface of the insulating isolation layer under mechanical stress and thermal stress. Ni plays the role of adhering the Cr layer. Cr has high strength and good conductivity. After oxidation, the surface can form a dense insulating oxide film to prevent further corrosion and improve the mechanical properties of the mask. During the operation of the electrostatic adsorption mask, the Cu / Ni / Cr composite metal film can be connected to an electrostatic generator, and the mask can be tightly adsorbed on a semiconductor or conductor substrate through electrostatic action, thereby reducing undesirable phenomena such as shadows during the vapor deposition process.

[0051] In some embodiments, the electrostatically adsorbed conductive layer can have a variety of shapes, structures and numbers of layers. The material of the electrostatically adsorbed conductive layer can be a conductor or semiconductor material with a certain conductivity, and is composed of materials including but not limited to aluminum, copper, titanium, nickel, chromium, tantalum, tungsten, indium tin oxide, zinc oxide, carbon fiber, conductive polymer, heavily doped silicon, semiconductor gallium arsenide, semiconductor perovskite material, organic semiconductor material, etc., or a composite or doped material of one or more of the above.

[0052] Afterwards, in the embodiment of the present disclosure, the substrate 110 on which the electrostatically adsorbed conductive layer 101 is deposited is transferred to a spin coater, and a positive photoresist is spin-coated on the surface of the electrostatically adsorbed conductive layer 101, exposed through a mask, baked, developed and cleaned, thereby forming a patterned photoresist mask on the surface of the electrostatically adsorbed conductive layer 101.

[0053] In the disclosed embodiment, the opening shape of the photoresist pattern is hexagonal, and the side length of the hexagon is 1.6 μm. The thickness of the patterned photoresist is 4 μm. In some embodiments, the photoresist is polyester film photoresist.

[0054] Next, the substrate 110 with patterned photoresist on its surface is transferred to a dry etching machine and placed horizontally, that is, the inclination angle between the plane of the substrate 110 and the horizontal direction is 0°, and the electrostatically adsorbed conductive layer 101 is vertically etched using Cl2 / Ar gas for 15 minutes. The electrostatically adsorbed conductive layer 101 in the patterned photoresist protection area on the substrate 110 is not etched, and the electrostatically adsorbed conductive layer 101 area not protected by the photoresist is completely etched away, exposing the insulating isolation layer 100 on the first surface of the substrate 110. Thereafter, a solvent stripping bath (Baker PRS-2000Resist Stripper) is used to clean at 90°C for 10 minutes to remove the patterned photoresist. Next. The wafer is rinsed with deionized water for 10 minutes, immersed in isopropyl alcohol and slowly pulled out, thereby forming the patterned electrostatically adsorbed conductive layer 101. The specific structure is as follows: Figure 3d As shown, the pattern of the electrostatic adsorption conductive layer 101 is the mask pattern of the electrostatic adsorption mask.

[0055] S4: etching the insulating isolation layer using a dry etching process to form a through hole with a trapezoidal cross section.

[0056] In some embodiments, in order to ensure that the mask still has good mechanical properties under the condition of very small shadow effect, it is generally necessary to increase the thickness of its non-functional area as much as possible. The methods include but are not limited to making the through-hole sidewalls with a certain inclination angle, curved sidewalls, or making the through-hole sidewalls into a stepped structure.

[0057] In the embodiment of the present disclosure, the dry etching process includes: placing the substrate on the sample stage of the dry engraving machine and performing n etchings, and rotating the sample stage by α° in the same direction around the vertical center axis of the sample stage after each etching, and the sample stage is set in the dry engraving machine at an angle k inclined to the horizontal direction of the dry engraving machine, wherein the range of α is 0-180°, n*α°=360°, and the range of k is 0-90°.

[0058] Specifically, in the embodiments of the present disclosure, Figure 4 The structure diagram of the dry etching machine used for etching the insulating isolation layer in the embodiment of the present disclosure is shown. Figure 4 The dry etching machine used for etching the insulating isolation layer 100 is a dry etching machine with a multi-degree-of-freedom sample stage, wherein the movement direction 400 of the dry etching gas is vertically downward. The sample stage of the dry etching machine clamps the substrate 110 through an electrostatic chuck and can move 0-90° tilted from the horizontal direction.

[0059] In the embodiment of the present disclosure, the first surface of the substrate 110 formed with the insulating isolation layer 100 is placed upward on the sample stage in the dry etching machine, and the inclination angle between the plane of the sample stage and the horizontal direction is set to 10°, that is, the inclination angle between the plane of the substrate 110 and the horizontal direction is 10°. The insulating isolation layer 100 that is not protected by the patterned electrostatic adsorption conductive layer 101 is etched using SF6 / Ar, and the etching time is 5 minutes. During the dry etching process, the dry etching gas accelerated by induction or magnetic field etches downward in a direction parallel to the side wall of the dry etching machine cavity, that is, perpendicular to the upper and lower planes of the dry etching machine, and etches the area of ​​the insulating isolation layer 100 that is not protected by the electrostatic adsorption conductive layer 101. Since the plane of the substrate 110 has an inclination angle with the horizontal direction of the dry etching machine, the dry etching gas will perform inclined etching on the insulating isolation layer 100, so that the side wall of the through hole formed by etching the insulating isolation layer 100 is an inclined side wall, rather than a side wall perpendicular to the horizontal plane.

[0060] Then rotate the sample stage 120° clockwise around the vertical center axis of the dry engraver and etch again for 5 minutes, then rotate it 120° clockwise again and etch for 5 minutes. Figure 3e , a through hole 108 with a trapezoidal cross-sectional shape is formed in the insulating isolation layer 100. Since three inclined etchings are performed and the angle between the injection direction of the dry etching gas and the insulating isolation layer 100 is the same during each etching process, the through hole 108 formed by the inclined etching has a regular hexagonal shape in the direction of the first surface of the substrate 110, and the through hole 108 is a hexagonal pyramid-shaped through hole.

[0061] Can be combined Figure 5 and Figure 6 Understand the tilted etching process, Figure 5 The process of forming a through hole with a trapezoidal cross section by multiple inclined etchings is shown. Figure 5 (a) is the first oblique etching, 400 is the ion beam etching direction, in the first oblique etching, the dry etching gas is obliquely injected into the insulating isolation layer 100, and a region with a parallelogram cross section is etched in the insulating isolation layer 100, and the angle between the dry etching gas and the insulating isolation layer 100 is equal to the inclination angle of the sample stage of the dry etching machine and the vertical direction; the substrate 110 is rotated around the central axis by a certain angle α, and the insulating isolation layer 100 is subjected to a second oblique etching, as shown in FIG. Figure 5 As shown in (b), the parallelogram shape formed by the second oblique etching partially overlaps with the shape formed by the first etching, and a through hole with a trapezoidal cross section is formed in the insulating isolation layer 100.

[0062] Figure 6 An example of a top view structural schematic diagram of a patterned insulating isolation layer having a trapezoidal through-hole cross section obtained by multiple inclined dry etching is shown. Figure 6(a) and (b) are through holes formed by etching four times and three times, respectively, where the arrows indicate the direction of each tilted etching. In order to ensure the symmetry of the through hole, the rotation angle α is generally 180°, 120°, 90°, etc., and the number of tilted etchings is 2, 3, and 4 times accordingly. For through holes with a rectangular shape when viewed from above, etching is generally selected 2 or 4 times, with a rotation of 180° or 90° after each etching; for through holes with a hexagonal shape when viewed from above, etching is generally selected 2 or 3 times, with a rotation of 180° or 120° after each etching.

[0063] In some embodiments, the sample stage plane can be set to be inclined at an arbitrarily set angle k relative to the horizontal direction of the dry etching machine, and the range of k is 0-90°. The larger the angle k, the larger the inclination angle of the trapezoidal through hole formed on the insulating isolation layer 100. In the embodiment of the present disclosure, the through hole 108 is a trapezoidal through hole with an inclination angle of 10°.

[0064] In some embodiments, in the dry engraving machine, the sample stage can rotate in a clockwise direction or a counterclockwise direction, as long as it is ensured that in n etchings in one dry etching process step, the sample stage rotates in the same direction around the vertical center axis of the sample stage after each etching.

[0065] In some embodiments, the size of the through hole is generally 0.1-20 μm, and the shape of the through hole 108 on the first surface of the substrate includes but is not limited to various shapes such as quadrilateral, hexagon, octagon and their combinations.

[0066] The preparation method of the electrostatic adsorption mask provided in the embodiment of the present disclosure uses a three-time tilt dry etching scheme to in-situ manufacture an electrostatic adsorption mask with an electrostatic shielding structure on a silicon wafer, and the cross-section of the through-hole sidewall of the mask is a trapezoid. Since SiO2 has a low linear thermal expansion coefficient and good compressive strength, and metal has good tensile strength, the electrostatic adsorption mask has good mechanical properties and low thermal deformation.

[0067] In some embodiments, in order to increase the corrosion resistance and mechanical properties of the electrostatic adsorption mask and reduce the risks of electrostatic breakdown, a passivation layer may be introduced therein. The passivation layer includes but is not limited to an oxide layer formed by in-situ reactions of the electrostatic adsorption conductive layer, the electrostatic shielding conductive layer, the insulating layer and the ribs, and a surface film layer introduced by other means. The in-situ reaction includes but is not limited to in-situ oxidation and fluorination of metals, and the surface film layer introduced by other means includes but is not limited to chemical vapor deposition of silicon nitride, atomic layer deposition of aluminum oxide, chemical electroplating of metals or metal oxides, solution-based surface deposition of polymers, surface sintering of enamel layers, and other surface treatment and protection methods. One or more combinations thereof are not limited in this disclosure.

[0068] In the embodiment of the present disclosure, after the trapezoidal cross-section through hole 108 is formed, the electrostatically adsorbed conductive layer 101 is oxidized to form an oxide layer 103. Specifically, the substrate 110 in the dry etching machine is adjusted to an inclination angle of 0° with respect to the horizontal plane, and the electrostatically adsorbed conductive layer 101 is oxidized using oxygen plasma for 5 minutes to form a dense oxide layer 103 on the surface of the electrostatically adsorbed conductive layer 101. Figure 3f , the oxide layer 103 completely covers the surface of the electrostatically adsorbed conductive layer 101 .

[0069] In some embodiments, the thickness of the oxide layer may be 10-50 nm. Preferably, the thickness of the oxide layer may be 20-40 nm. In this embodiment, the thickness of the isolation layer 103 is 30 nm.

[0070] S5: etching the substrate from the second surface of the substrate to form a plurality of openings, wherein the openings correspond to the mask pattern regions of the mask plate.

[0071] In some embodiments, before etching the second surface of the substrate, a photoresist film may be used to protect the mask pattern on the first surface of the substrate to prevent the alkaline solution used for etching from etching the mask pattern. In the disclosed embodiment, before etching the second surface of the substrate, the substrate having the hexagonal pyramid-shaped through holes and an oxide layer formed on the surface of the electrostatically adsorbed conductive layer is taken out of the dry engraving machine, and a polyurethane photoresist with a thickness of 2 μm is spin-coated on the first surface of the substrate and dried to prevent the etching solution from corroding the mask pattern on the first surface of the substrate during the etching of the substrate from the second surface of the substrate.

[0072] Then, the substrate is etched from the second surface of the substrate to form a plurality of openings, such as Figure 3g As shown, the opening corresponds to the mask pattern area of ​​the mask. Specifically, a wet etching process is first used to etch the substrate 110 from the second surface of the substrate 110 using a 40% KOH aqueous solution at 40°C. The first surface of the substrate 110 is not affected by the etching solution due to the protection of the photoresist. The area of ​​the second surface of the substrate 110 that is not protected by the insulating oxide layer 110 is etched away at a rate of 1 μm / minute. Since the etching rate ratio of the KOH solution to Si and SiO2 is about 500:1, Figure 3gIn the embodiment shown, the substrate 110 is a silicon wafer, and the insulating isolation layer 100 is SiO2, so the substrate 110 is not affected by the etching solution in the area protected by the insulating oxide layer 110. After etching for about 5 hours, the substrate area not protected by the insulating oxide layer 110 is etched through from the second surface of the substrate 110, exposing the insulating oxide layer of the first surface at the corresponding position, that is, the insulating oxide layer / electrostatic adsorption conductive layer / oxide layer structure at the opening position of the substrate 110 is suspended in the air, becoming a self-supporting structure, and at the same time exposing the through hole 108 of the mask. After that, the substrate 110 is rinsed with deionized water in a cascade for 10 minutes, and the protective photoresist on the front is removed with piranha etching solution. After rinsing with deionized water again for 10 minutes, the substrate 110 is immersed in isopropyl alcohol (IPA), slowly pulled out and dried.

[0073] In the process of manufacturing the mask, in order to reduce the shadow effect, the thickness of the fine mask is generally comparable to the opening size, which reduces the thickness of some fine masks with pixel openings of about 1μm to about 1μm or even sub-micron, making the mask very fragile. In order to enhance the mechanical properties of the fine mask, a substrate of sufficient thickness is generally retained in the non-pixel area of ​​the mask as a reinforcing structure. This structure is generally called a reinforcing rib or reinforcing rib, generally referred to as a rib. Without these ribs, a mask film with a diameter of several hundred millimeters but a thickness of only a few microns or even less than one micron and full of holes will be too fragile to be transferred and used. In the disclosed embodiment, the portion of the substrate that is not etched serves as a reinforcing structure for the electrostatic adsorption mask.

[0074] S6: forming an electrostatic shielding conductive layer on one side of the second surface of the substrate, wherein the second surface of the substrate is opposite to the first surface of the substrate.

[0075] In this embodiment, the second surface of the substrate 110 is placed horizontally in a PVD device with the second surface facing upward, and a titanium / nickel / copper composite film is deposited on the second surface of the substrate 110 by a magnetron sputtering process as an electrostatic shielding conductive layer 102. The specific structure is as follows: Figure 3h As shown, the thickness of the titanium film is 20nm, the thickness of the nickel film is 20nm, and the thickness of the copper film is 100-200nm. The electrostatic shielding conductive layer 102 is shielded between the electrostatic adsorption conductive layer 101 and the gas phase material, and is grounded through a wire so that the electrostatic adsorption conductive layer 101 does not affect the movement of the gas phase material.

[0076] In some embodiments, the electrostatic shielding conductive layer can have a variety of shapes, structures and numbers of layers. The material of the electrostatic shielding conductive layer can be a conductor or semiconductor material with a certain conductivity, and is composed of materials including but not limited to aluminum, copper, titanium, nickel, chromium, tantalum, tungsten, indium tin oxide, zinc oxide, carbon fiber, conductive polymer, heavily doped silicon, semiconductor gallium arsenide, semiconductor perovskite material, organic semiconductor material, etc., or a composite or doped material of one or more of the above.

[0077] In the embodiments of the present disclosure, Figure 3h As shown, in the mask pattern area of ​​the electrostatic adsorption mask, the electrostatic shielding conductive layer 102 and the electrostatic adsorption conductive layer 101 are isolated by the insulating isolation layer 100 on the first surface of the substrate; on both sides of the mask pattern of the electrostatic adsorption mask, that is, Figure 3h In the region of the middle substrate 110 , the electrostatic shielding conductive layer 102 and the electrostatic adsorption conductive layer 101 are isolated from each other by an insulating isolation layer / substrate / insulating isolation layer structure.

[0078] The structure used to isolate the electrostatic adsorption conductive layer and the electrostatic shielding conductive layer generally requires an insulating material or semiconductor material with poor conductivity. Preferably, it is a composite or doped structure of one or more insulating materials such as silicon oxide, silicon nitride, photoresist, low thermal expansion glass, low thermal expansion polymer, vacuum, etc. Wherein vacuum means that, in some cases, the gap between the electrostatic adsorption conductive layer and the electrostatic shielding conductive layer is not directly filled with any material, and only the supporting structure of the two in other areas is maintained so that they will not attract each other and cause contact. Semiconductor materials such as silicon, organic-inorganic hybrid perovskite, and organic semiconductors can also be used for isolation structures, but materials or material combinations with suitable resistivity should be selected according to the conductivity of the electrostatic adsorption conductive structure and the electrostatic adsorption voltage to prevent uneven electrostatic adsorption force and thermal deformation of the mask due to local overheating caused by leakage current.

[0079] The isolation structure can also have the function of a skeleton at the same time, because the thermal expansion coefficient of most conductive materials is difficult to completely match the thermal expansion coefficient of the substrate, especially when single crystal silicon is used as the substrate. Due to its very low thermal expansion coefficient, only a very small number of materials such as Invar alloy can meet the demand, and there are huge difficulties in its production, processing and use. In order to increase the selection range of conductive layer materials, materials with a thermal expansion coefficient matching that of the substrate can be used as the basic skeleton and isolation layer. At this time, the isolation structure with the skeleton function is required to have a thermal expansion coefficient matching that of the substrate and good mechanical properties. Generally, one or more composite or doped materials such as silicon, silicon oxide, silicon nitride, ordinary glass, low thermal expansion glass, low thermal expansion polyimide, silicon carbide, diamond, aluminum oxide, chromium oxide and other inorganic non-metallic materials, metal oxides, organic materials, etc. are selected.

[0080] In some embodiments, referring to the structure of a Faraday cage, the electrostatic shielding conductive layer does not have to be a whole and may have certain gaps. Figure 7 Some schematic cross-sectional structures of simple electrostatic adsorption masks with electrostatic shielding structures are shown, wherein the electrostatic adsorption conductive layer 101 and the electrostatic shielding conductive layer 102 are both single-layer structures.

[0081] In some embodiments, in order to reduce the production cost of the electrostatic adsorption mask or achieve better performance, the production process of the mask includes additive manufacturing and subtractive manufacturing or a hybrid solution thereof. For example, the production process of the pixel definition layer of the electrostatic adsorption mask includes but is not limited to a combination of one or more methods such as chemical reaction in-situ growth, mask vapor deposition, mask solution electroforming deposition, imprinting, model injection molding, printing, mechanical engraving, wet etching, dry etching, laser etching, electron beam etching, ion beam etching, etc., and the present disclosure is not limited thereto.

[0082] The electrostatic adsorption mask containing an electrostatic shielding structure prepared in the embodiment of the present disclosure surrounds the electrostatic adsorption conductive layer and the area outside the vapor deposition substrate through the electrostatic shielding conductive layer. During use, the electrostatic adsorption conductive layer is connected to the electrostatic generator through a wire, and the electrostatic adsorption mask is attached to the substrate through the electrostatic effect, thereby reducing the shadow and other defects during the vapor deposition process. The electrostatic shielding conductive layer is blocked between the electrostatic adsorption conductive layer and the vapor phase material, and is grounded through a wire, so that the electrostatic adsorption conductive layer will not affect the movement of the vapor phase material, which greatly improves the quality of thin film deposition and reduces the plugging speed.

[0083] The disclosed embodiment also provides a system for manufacturing an electrostatic adsorption mask template, comprising: a deposition unit, used to form an insulating isolation layer on a first surface of a substrate, and to form a patterned electrostatic adsorption conductive layer on the insulating isolation layer; an etching unit, used to perform multiple etchings on the insulating isolation layer on the first surface of the substrate placed on a sample stage of a dry etching machine in a dry etching process step to form a through hole with a trapezoidal cross-section; an angle control unit, used to perform n etchings in the dry etching process step, and after each etching, rotate the sample stage in the same direction by α° around the vertical center axis of the sample stage, wherein the sample stage is arranged in the dry etching machine at an angle k inclined to the horizontal direction of the dry etching machine, wherein the range of α is 0-180°, n*α°=360°, and the range of k is 0-90°; the etching unit is also used to etch the substrate from the second surface of the substrate to form a plurality of openings, wherein the openings correspond to the mask pattern area of ​​the mask template; the deposition unit is also used to form an electrostatic shielding conductive layer from one side of the second surface of the substrate, wherein the second surface of the substrate is opposite to the first surface of the substrate.

[0084] Specifically, in the process of making the electrostatic adsorption mask template of the embodiment of the present disclosure, the deposition unit controls the tube furnace to form an insulating isolation layer on the first surface and the second surface of the substrate; the etching unit controls the etching equipment to etch the insulating isolation layer on the second surface of the substrate to expose the substrate in the mask pattern area. Afterwards, the deposition unit controls the PVD equipment to form an electrostatic adsorption conductive layer on the insulating isolation layer on the first surface of the substrate. Then, the etching unit controls the etching equipment to etch the electrostatic adsorption conductive layer to form a patterned electrostatic adsorption conductive layer; then, the etching unit controls the dry engraving machine again to etch the insulating isolation layer on the first surface of the substrate placed on the sample stage of the dry engraving machine multiple times to form a through hole with a trapezoidal cross-section.

[0085] In the process step of etching the insulating isolation layer multiple times, the angle control unit is used to control the tilt and rotation of the sample stage. Specifically, before dry etching the insulating isolation layer, the angle control unit controls the sample stage to be tilted at an angle k in the dry etching machine relative to the horizontal direction of the dry etching machine, and the range of k is 0-90°. In the dry etching process step including n etchings, after each etching, the angle control unit controls the sample stage to rotate α° around the vertical center axis of the sample stage in the same direction, and then performs the next etching, and the range of α is 0-180°, n*α°=360°.

[0086] Next, the deposition unit controls the oxidation device to oxidize the electrostatically adsorbed conductive layer from the first surface side of the substrate to form an oxide layer on the electrostatically adsorbed conductive layer. The etching unit then controls the etching device to etch the substrate from the second surface of the substrate to form a plurality of openings, the openings corresponding to the mask pattern area of ​​the mask. Afterwards, the deposition unit controls the PVD device to form an electrostatic shielding conductive layer from the second surface side of the substrate, the second surface of the substrate being opposite to the first surface of the substrate.

[0087] The embodiments of the present disclosure provide an electrostatic adsorption mask, a method for manufacturing an electrostatic adsorption mask, and a manufacturing system, which can form an electrostatic adsorption mask with good mechanical properties and low thermal deformation. Compared with an electrostatic adsorption mask without an electrostatic shielding structure, the electrostatic adsorption mask with an electrostatic shielding structure provided by the present disclosure surrounds an electrostatic shielding conductive layer outside the electrostatic adsorption conductive layer, and grounds the electrostatic shielding conductive layer, so that the electric field can only terminate between the electrostatic shielding layer and the substrate, without any leakage, and will not affect the deposition of polar gaseous materials on the substrate, thereby improving the fineness of the mask.

[0088] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structural or equivalent process transformations made using the contents of the specification and drawings of the present application, such as the mutual combination of technical features between the embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An electrostatic adsorption mask, characterized in that: include: A substrate having a plurality of openings, wherein the openings correspond to mask pattern regions of the mask plate; An insulating isolation layer having a mask pattern disposed between the first surface of the substrate and the substrate stack, wherein the mask pattern includes a through hole with a trapezoidal cross section; An electrostatic adsorption conductive layer is disposed on the insulating isolation layer and is used to obtain electrostatic charge from an external electrostatic generator; An electrostatic shielding conductive layer covers the second surface of the substrate, the surface of the insulating isolation layer at the opening, and the sidewall of the through hole, and is grounded; Wherein, the second surface of the substrate is opposite to the first surface of the substrate.

2. The electrostatic adsorption mask according to claim 1, characterized in that: Also includes: An insulating isolation layer is located on the second surface of the substrate.

3. The electrostatic adsorption mask according to claim 2, characterized in that: The material of the insulating isolation layer is silicon dioxide.

4. The electrostatic adsorption mask according to claim 1, characterized in that: The through hole has a shape of a quadrilateral, a hexagon, an octagon, or a combination thereof.

5. The electrostatic adsorption mask according to any one of claims 1 to 4, characterized in that: The material of the electrostatic adsorption conductive layer is a conductor or a semiconductor.

6. The electrostatic adsorption mask according to any one of claims 1 to 4, characterized in that: The electrostatic shielding conductive layer is made of a conductor or a semiconductor.

7. A method for making an electrostatic adsorption mask, characterized in that: include: providing a substrate; forming an insulating isolation layer on the first surface of the substrate; forming a patterned electrostatically adsorbed conductive layer on the insulating isolation layer; The insulating isolation layer is etched by a dry etching process to form a through hole with a trapezoidal cross section, wherein the dry etching process comprises: placing the substrate on a sample stage of a dry etching machine and performing n etchings, rotating the sample stage in the same direction around the vertical center axis of the sample stage by α° after each etching, wherein the sample stage is arranged in the dry etching machine at an angle k inclined to the horizontal direction of the dry etching machine, wherein the range of α is 0-180°, n*α°=360°, and the range of k is 0-90°; Etching the substrate from the second surface of the substrate to form a plurality of openings, wherein the openings correspond to the mask pattern regions of the mask plate; An electrostatic shielding conductive layer is formed on one side of the second surface of the substrate, and the second surface of the substrate is opposite to the first surface of the substrate.

8. The method for making an electrostatic adsorption mask according to claim 7, characterized in that: Also includes: After providing the substrate, forming an insulating isolation layer on the second surface of the substrate; The insulating isolation layer on the second surface of the substrate is etched to expose the substrate in the mask pattern area.

9. The method for manufacturing an electrostatic adsorption mask according to claim 8, characterized in that: The material of the insulating isolation layer is silicon dioxide.

10. The method for manufacturing an electrostatic adsorption mask according to claim 7, characterized in that: The substrate is a silicon wafer.

11. The method for manufacturing an electrostatic adsorption mask according to claim 7, characterized in that: The through hole has a shape of a quadrilateral, a hexagon, an octagon, or a combination thereof.

12. The method for manufacturing an electrostatic adsorption mask according to any one of claims 7 to 11, characterized in that: The material of the electrostatic adsorption conductive layer is a conductor or a semiconductor.

13. The method for manufacturing an electrostatic adsorption mask according to any one of claims 7 to 11, characterized in that: The electrostatic shielding conductive layer is made of a conductor or a semiconductor.

14. A system for making an electrostatic adsorption mask, characterized in that: include: A deposition unit, used to form an insulating isolation layer on the first surface of the substrate, and to form a patterned electrostatically adsorbed conductive layer on the insulating isolation layer; An etching unit, used for etching the insulating isolation layer on the first surface of the substrate placed on the sample stage of the dry etching machine for multiple times in the dry etching process step to form a through hole with a trapezoidal cross section; An angle control unit, used for performing n etchings in the dry etching process step, rotating the sample stage by α° in the same direction around the vertical center axis of the sample stage after each etching, wherein the sample stage is arranged in the dry etching machine at an angle k inclined to the horizontal direction of the dry etching machine, wherein the range of α is 0-180°, n*α°=360°, and the range of k is 0-90°; The etching unit is further used for etching the substrate from the second surface of the substrate to form a plurality of openings, wherein the openings correspond to the mask pattern areas of the mask plate; The deposition unit is also used to form an electrostatic shielding conductive layer from one side of the second surface of the substrate, and the second surface of the substrate is opposite to the first surface of the substrate.

15. The electrostatic adsorption mask manufacturing system according to claim 14, characterized in that: The deposition unit is also used to form an insulating isolation layer on the second surface of the substrate.

16. The electrostatic adsorption mask manufacturing system according to claim 14, characterized in that: The etching unit is also used to etch the insulating isolation layer on the second surface of the substrate to expose the substrate in the mask pattern area.

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