A method for depositing a magnesium fluoride film by nitrogen ion assistance
By using nitrogen ion-assisted coating, magnesium fluoride films are formed at low temperatures using nitrogen ionization. This solves the problem of poor weather resistance caused by high film stress under argon ion-assisted coating, and extends film life and expands the process adjustment window.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KEYMANG OPTRONIC SCI & TECH CO LTD IN ANHUI
- Filing Date
- 2026-02-09
- Publication Date
- 2026-05-29
AI Technical Summary
In existing low-temperature magnesium fluoride coating processes, the stress in the film layer is relatively high when using argon ion assistance, resulting in poor weather resistance and easy cracking when coating on plastic substrates such as PMMA and PC.
A nitrogen ion-assisted deposition method is adopted, in which nitrogen is used instead of argon for ionization at low temperature, the temperature of the vacuum chamber is controlled at 50℃~140℃, and the voltage and current of the accelerating electric field are adjusted to form a nitrogen ion-assisted deposition magnesium fluoride film.
It significantly reduces membrane stress, improves membrane weather resistance, extends membrane life, and increases the process adjustment window.
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Figure CN122105311A_ABST
Abstract
Description
Technical Field
[0001] This specification relates to the field of vacuum coating technology, and in particular to a method for nitrogen ion-assisted deposition of magnesium fluoride films. Background Technology
[0002] The description in this section provides only background information relevant to the disclosure in this specification and does not constitute prior art.
[0003] When magnesium fluoride materials are vacuum-deposited into thin films, a high temperature of 250~300℃ is required to ensure film adhesion. If film formation at a lower temperature is required, an ion source is needed. The principle of ion source-assisted deposition is as follows: a high-frequency alternating magnetic field generated by passing a high-frequency alternating current through a coil guides electrons in the magnetic field to collide with gas molecules, causing the gas molecules to ionize. Then, an accelerating electric field accelerates the gas ions and ejects them to bombard the film layer.
[0004] Existing low-temperature magnesium fluoride plating processes use argon gas, an inert gas, in the ion source for argon-assisted plating. However, since the accelerating voltage of current mainstream radio frequency ion sources is generally no less than 250V, and argon atoms have a relatively large mass of approximately 40u, the film layer experiences significant impact during plating, resulting in high stress. When plating on plastic substrates such as PMMA and PC, the high thermal expansion coefficient of the substrate often leads to rapid cracking of the high-stress film layer during weathering tests involving high temperature and humidity, and high and low temperature shocks.
[0005] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions in this specification and facilitating understanding by those skilled in the art. The fact that these solutions have been described in the background section of this specification should not be construed as meaning that the aforementioned technical solutions are known to those skilled in the art. Summary of the Invention
[0006] In view of the shortcomings of the prior art, one object of this specification is to provide a method for nitrogen ion-assisted deposition of magnesium fluoride films, which can significantly reduce the lower stress limit of the film and increase the process adjustment window.
[0007] To achieve the above objectives, this specification provides a method for nitrogen ion-assisted deposition of magnesium fluoride films, comprising the following steps:
[0008] A vacuum chamber for coating is prepared; the vacuum chamber contains a substrate and magnesium fluoride material; the temperature inside the vacuum chamber is below 250°C.
[0009] Prepare an ion source; the ion source is connected to the vacuum chamber; nitrogen gas is introduced into the ion source, and the nitrogen gas is ionized into nitrogen ions in the ion source;
[0010] Nitrogen ions are introduced into the vacuum chamber, and the magnesium fluoride material is deposited on the substrate surface with the assistance of the nitrogen ions to form a magnesium fluoride film.
[0011] In a preferred embodiment, during the step of preparing the vacuum chamber for coating, the temperature inside the vacuum chamber is 50°C to 140°C.
[0012] In a preferred embodiment, the temperature inside the vacuum chamber is controlled to fluctuate within ±5°C.
[0013] In a preferred embodiment, the temperature inside the vacuum chamber is 80°C to 90°C.
[0014] In a preferred embodiment, in the step of preparing the ion source, an accelerating electric field is applied to the ion source, wherein the voltage of the accelerating electric field is 250V~1200V and the current of the accelerating electric field is 250mA~2000mA.
[0015] In a preferred embodiment, the voltage of the accelerating electric field is 300V and the current of the accelerating electric field is 350mA.
[0016] In a preferred embodiment, in the step of preparing the ion source, the flow rate of nitrogen gas introduced into the ion source is 30 sccm to 100 sccm.
[0017] In a preferred embodiment, in the step of preparing the ion source, the flow rate of nitrogen gas introduced into the ion source is 50 sccm.
[0018] In a preferred embodiment, during the step of introducing nitrogen ions into the vacuum chamber, the evaporation rate of the magnesium fluoride material is 3 A / s to 10 A / s.
[0019] In a preferred embodiment, during the step of introducing nitrogen ions into the vacuum chamber, the evaporation rate of the magnesium fluoride material is 5 A / s.
[0020] Beneficial effects:
[0021] The nitrogen ion-assisted deposition method for magnesium fluoride films provided in this embodiment deposits magnesium fluoride films at low temperatures. The ion source uses nitrogen gas instead of traditional argon gas, solving the problem that excessive argon energy can adversely affect film stress and the plastic substrate. Nitrogen gas is ionized into nitrogen ions in the ion source; the atomic mass of nitrogen ions is approximately 14u. Based on the velocity formula of charged particles in an electric field… And momentum formula , can be obtained (Where p represents the momentum of the object, in kg·m / s; m represents the mass of the object, in kg; v represents the velocity of the object, in m / s; q represents the charge, in C; and U represents the voltage, in V). Under the same accelerating voltage U, the momentum of an argon ion is approximately equal to that of a nitrogen ion. The difference is significant; as can be seen from the comparison of argon ion assistance, nitrogen ion assistance can significantly reduce the lower stress limit of the film and increase the adjustment window of the process.
[0022] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.
[0023] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.
[0024] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a flowchart illustrating the steps of a nitrogen ion-assisted deposition method for magnesium fluoride film provided in this embodiment. Detailed Implementation
[0027] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.
[0028] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.
[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0030] Please see Figure 1 This application provides a method for nitrogen ion-assisted deposition of magnesium fluoride (MgF2) films, comprising the following steps:
[0031] Step S10: Prepare a vacuum chamber for coating.
[0032] The vacuum chamber contains a substrate and magnesium fluoride (MgF2) material. The substrate material includes, but is not limited to, various plastics and glass. Considering that plastic and glass substrates are not heat-resistant, the temperature inside the vacuum chamber needs to be controlled below 250°C.
[0033] In this embodiment, in the step of preparing the vacuum chamber for coating (i.e., step S10), the temperature inside the vacuum chamber is adjusted as needed. Preferably, the temperature inside the vacuum chamber is controlled to be 50°C to 140°C. Further, the temperature inside the vacuum chamber is controlled to have fluctuations of less than ±5°C. Preferably, the temperature inside the vacuum chamber is 80°C to 90°C.
[0034] Step S20: Prepare the ion source.
[0035] The ion source is connected to a vacuum chamber. Nitrogen gas is introduced into the ion source. The nitrogen gas is ionized into nitrogen ions in the ion source. The ion source in this application is a radio frequency ion source.
[0036] Specifically, in the step of preparing the ion source (i.e., step S20), an accelerating electric field is applied to the ion source. The voltage of the accelerating electric field is 250V~1200V, and the current is 250mA~2000mA. The voltage of the accelerating electric field cannot be too high because nitrogen is not an inert ion and will undergo a slight chemical reaction with Mg, filling lattice defect sites and forming Mg–N or Mg–F–N impurity phases, thereby changing the stoichiometry and optical properties of MgF2 and affecting the deposition of the magnesium fluoride film. The voltage of the accelerating electric field also cannot be too low, otherwise nitrogen gas will not be able to be ionized.
[0037] Preferably, the voltage of the accelerating electric field is 300V and the current of the accelerating electric field is 350mA, which can ensure that nitrogen gas is ionized into nitrogen ions and that no impurities (such as magnesium nitride) are introduced into the vacuum cavity.
[0038] In this embodiment, in the step of preparing the ion source (i.e., step S20), the flow rate of nitrogen gas introduced into the ion source is 30 sccm to 100 sccm. Too low a flow rate will affect the coating efficiency, while too high a flow rate will lead to nitrogen waste. Preferably, the flow rate of nitrogen gas introduced into the ion source is 50 sccm.
[0039] It should be noted that this application does not limit the order of steps S10 and S20. Steps S10 and S20 can be performed simultaneously, or steps S10 can be performed first and then steps S20, or steps S20 can be performed first and then steps S10.
[0040] Step S30: Nitrogen ions are introduced into the vacuum chamber, and magnesium fluoride material is deposited on the substrate surface with the assistance of nitrogen ions to form a magnesium fluoride film.
[0041] Specifically, in the step of introducing nitrogen ions into the vacuum chamber (i.e., step S30), the evaporation rate of the magnesium fluoride material is 3 A / s to 10 A / s. Preferably, the evaporation rate of the magnesium fluoride material is 5 A / s.
[0042] In one specific embodiment, a vacuum chamber for film deposition is prepared. The vacuum chamber contains a substrate and magnesium fluoride material. The temperature within the vacuum chamber is controlled to be 80°C~90°C. An ion source is prepared. Nitrogen gas is introduced into the ion source at a flow rate of 50 sccm. An accelerating voltage of 300V and an accelerating current of 350mA are applied to the ion source, causing the nitrogen gas to be ionized into nitrogen ions. The nitrogen ions are then introduced into the vacuum chamber, and the magnesium fluoride material is deposited on the substrate surface with the assistance of the nitrogen ions to form a magnesium fluoride film. The deposition rate of the magnesium fluoride material is 5A / s.
[0043] In a comparative example, argon was used instead of nitrogen, and other process conditions remained unchanged to obtain a coated substrate. The substrate and the coated substrate of the above embodiment were subjected to a double 85 test. It was found that the film life obtained by argon-assisted deposition was 100h, while the film life obtained by nitrogen ion-assisted deposition of magnesium fluoride film provided in this application was 160h.
[0044] The nitrogen ion-assisted deposition method for magnesium fluoride film provided in this embodiment deposits magnesium fluoride film at low temperature. The ion source uses nitrogen gas instead of traditional argon gas, which solves the problem that the excessive energy of argon gas has an adverse effect on the stress of the film layer and the plastic substrate.
[0045] Nitrogen gas is ionized into nitrogen ions in an ion source. The atomic mass of a nitrogen ion is approximately 14 u. Based on the velocity formula of a charged particle in an electric field... And momentum formula , can be obtained (Where p represents the momentum of the object, in kg·m / s; m represents the mass of the object, in kg; v represents the velocity of the object, in m / s; q represents the charge, in C; and U represents the voltage, in V). Under the same accelerating voltage U, the momentum of an argon ion is approximately equal to that of a nitrogen ion. The difference is significant; as can be seen from the comparison of argon ion assistance, nitrogen ion assistance can significantly reduce the lower stress limit of the film and increase the adjustment window of the process.
[0046] It should be noted that, unless otherwise stated, "multiple" in this specification means two or more.
[0047] Any numerical values cited herein include all values ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values listed between the minimum and maximum values are explicitly described in this specification in a similar manner.
[0048] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.
[0049] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.
[0050] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.
[0051] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.
Claims
1. A method for nitrogen ion-assisted deposition of magnesium fluoride film, characterized in that, Includes the following steps: A vacuum chamber for coating is prepared; the vacuum chamber contains a substrate and magnesium fluoride material; the temperature inside the vacuum chamber is below 250°C. Prepare an ion source; the ion source is connected to the vacuum chamber; nitrogen gas is introduced into the ion source, and the nitrogen gas is ionized into nitrogen ions in the ion source; Nitrogen ions are introduced into the vacuum chamber, and the magnesium fluoride material is deposited on the substrate surface with the assistance of the nitrogen ions to form a magnesium fluoride film.
2. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 1, characterized in that, In the step of preparing the vacuum chamber for coating, the temperature inside the vacuum chamber is 50°C to 140°C.
3. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 2, characterized in that, The temperature inside the vacuum chamber is controlled to fluctuate within ±5℃.
4. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 3, characterized in that, The temperature inside the vacuum chamber is 80℃~90℃.
5. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 1, characterized in that, In the step of preparing the ion source, an accelerating electric field is applied to the ion source. The voltage of the accelerating electric field is 250V~1200V, and the current of the accelerating electric field is 250mA~2000mA.
6. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 5, characterized in that, The voltage of the accelerating electric field is 300V, and the current of the accelerating electric field is 350mA.
7. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 1, characterized in that, In the step of preparing the ion source, the flow rate of nitrogen gas introduced into the ion source is 30 sccm to 100 sccm.
8. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 7, characterized in that, In the step of preparing the ion source, the flow rate of nitrogen gas introduced into the ion source is 50 sccm.
9. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 1, characterized in that, In the step of introducing nitrogen ions into the vacuum chamber, the evaporation rate of the magnesium fluoride material is 3A / s to 10A / s.
10. The method for nitrogen ion-assisted deposition of magnesium fluoride film according to claim 9, characterized in that, In the step of introducing nitrogen ions into the vacuum chamber, the evaporation rate of the magnesium fluoride material is 5 A / s.