A membrane structure and its manufacturing method

Abstract

The present invention discloses a membrane structure and a method for manufacturing the same. The membrane structure is: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air; wherein Sub is the substrate, Air is the output medium air, H is a high-refractive-index material with an optical thickness of 1 / 4 the center wavelength, L is a low-refractive-index material with an optical thickness of 1 / 4 the center wavelength, and a, b, c, d, e, and f are all positive integers; wherein, (HL)^a represents the sequential deposition of the H film layer and the L film layer and is repeated a times; (2H)^b represents the sequential deposition of the H film layer and the H film layer and is repeated b times; (LH)^c represents the sequential deposition of the L film layer and the H film layer and is repeated c times; (2L)^d represents the sequential deposition of the L film layer and the L film layer and is repeated d times; ((HL)^a(2H)^b(LH)^c(2L)^d)^e represents the film stack (HL)^a(2H)^b(LH)^c(2L)^d repeated e times; fL represents the L film layer repeated f times. The technical solution of the embodiment of the present invention can be used to correct the relative ratio of the optical thickness of high and low refractive index materials while correcting the uniformity of the film thickness, and is accurate and efficient.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of optical thin films, and in particular to a film structure and a manufacturing method thereof. Background Art

[0002] With the rapid development of science and technology, optical films are being used more and more widely in civil and military fields. At the same time, the market's requirements for the performance of optical film products are also getting higher and higher. How to prepare optical film components efficiently and at low cost has become an important issue.

[0003] In the preparation of optical thin films, the uniformity of thin film components and the thickness matching of the prepared thin film components are very important performance parameters. There are many types of optical thin films, and conventional thin films include long-wave pass, short-wave pass, high-reflection films and anti-reflection films. When the thickness of the high-refractive index and low-refractive index materials are not 1:1 matched, the spectrum itself will not be much different. In this case, it is entirely possible to produce qualified products using conventional correction methods. However, for some relatively high-precision thin films, such as high-steepness Edge Filter, high-steepness CWDM and Lan-WDM film systems, especially CWDM and Lan-WDM, the uniformity of such thin film components and the thickness matching of high and low refractive index materials are directly related to the yield of the thin film components.

[0004] Conventional film thickness correction methods primarily involve creating separate masks to correct the film thickness uniformity and thickness ratio for high- and low-refractive index materials. However, this method has significant drawbacks. First, the film thickness ratio of high- and low-refractive index materials cannot be effectively matched; second, the film thickness uniformity accuracy cannot meet the requirements for high-precision thin film production. Summary of the Invention

[0005] The embodiments of the present invention provide a film structure and a manufacturing method thereof, so as to correct the accuracy of the relative ratio of the optical thickness of the high refractive index material and the low refractive index material while correcting the uniformity of the film thickness.

[0006] In a first aspect, an embodiment of the present invention provides a membrane structure, wherein the membrane structure is:

[0007] Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air;

[0008] Where Sub is the substrate, Air is the output medium air, H is the high refractive index material with an optical thickness of 1 / 4 the center wavelength, L is the low refractive index material with an optical thickness of 1 / 4 the center wavelength, and a, b, c, d, e, and f are all positive integers;

[0009] Among them, (HL)^a means depositing the H film layer and the L film layer in sequence and repeating it a times; (2H)^b means depositing the H film layer and the H film layer in sequence and repeating it b times; (LH)^c means depositing the L film layer and the H film layer in sequence and repeating it c times; (2L)^d means depositing the L film layer and the L film layer in sequence and repeating it d times; ((HL)^a(2H)^b(LH)^c(2L)^d)^e means the membrane stack (HL)^a(2H)^b(LH)^c(2L)^d is repeated e times; fL means the L film layer is repeated f times.

[0010] Optionally, 1≤a≤5, 1≤c≤5.

[0011] Optionally, 1≤b≤2, 1≤d≤2, 1≤e≤2, 1≤f≤2.

[0012] Optionally, the high refractive index material is any one of Ta2O5, TiO2, HfO2, ZrO2, sulfide and selenide.

[0013] Optionally, the low refractive index material is any one of SiO2, Al2O3 and MgF2.

[0014] Optionally, the substrate is a quartz substrate, the high refractive index material is Ta2O5, and the low refractive index material is SiO2.

[0015] Optionally, a=5, b=2, c=5, d=3, e=1, f=1.

[0016] Optionally, the central wavelength is 1310 nm.

[0017] In a second aspect, an embodiment of the present invention provides a method for manufacturing a film structure, comprising:

[0018] providing a substrate;

[0019] According to the film structure, a high refractive index material and a low refractive index material are sequentially grown by physical vapor deposition;

[0020] Wherein, the film structure is:

[0021] Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air;

[0022] Wherein, Sub is the substrate, Air is the output medium air, H is a high-refractive-index material with an optical thickness of 1 / 4 the center wavelength, L is a low-refractive-index material with an optical thickness of 1 / 4 the center wavelength, and a, b, c, d, e, and f are all positive integers;

[0023] Among them, (HL)^a means depositing the H film layer and the L film layer in sequence and repeating it a times; (2H)^b means depositing the H film layer and the H film layer in sequence and repeating it b times; (LH)^c means depositing the L film layer and the H film layer in sequence and repeating it c times; (2L)^d means depositing the L film layer and the L film layer in sequence and repeating it d times; ((HL)^a(2H)^b(LH)^c(2L)^d)^e means the membrane stack (HL)^a(2H)^b(LH)^c(2L)^d is repeated e times; fL means the L film layer is repeated f times.

[0024] Optionally, according to the film structure, a high refractive index material and a low refractive index material are sequentially grown by physical vapor deposition, including:

[0025] According to the film structure, a high refractive index material and a low refractive index material are grown in sequence by physical vapor deposition. The relative thickness ratio coefficient of the high refractive index material and the low refractive index material is determined based on the bandwidth between the wavelength corresponding to the transmission peak on both sides of the central wavelength and the central wavelength. When the optical thickness ratio of the high refractive index material and the low refractive index material deviates from 1:1, the relative thickness ratio of the high refractive index material and the low refractive index material is corrected.

[0026] The technical solution of the embodiment of the present invention is to produce a film structure as follows: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air, so that the film structure is more sensitive to the thickness ratio of the film layer material when the reference spectral characteristic peak wavelength is used, and the spectral characteristic peak of this film structure is insensitive to the heterogeneity of the material. In addition, this film structure is a regular structure and is simple to produce. While correcting the uniformity of the film thickness, it can also efficiently determine and correct the film thickness ratio distribution of high and low refractive index materials, ensuring the accuracy of the relative ratio of the optical thickness of the high refractive index material and the low refractive index material. It is particularly suitable for high-precision thin film components such as CWDM and Lan-WDM. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a spectrum curve of a film structure provided by an embodiment of the present invention;

[0028] Figure 2 A schematic diagram of the designed spectrum and measured spectrum curves of a film structure provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0030] The film system structure provided by an embodiment of the present invention is: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air; wherein Sub is the substrate, Air is the emitting medium air, H is a high refractive index material with an optical thickness of 1 / 4 the center wavelength, L is a low refractive index material with an optical thickness of 1 / 4 the center wavelength, and a, b, c, d, e, and f are all positive integers.

[0031] Wherein, (HL)^a means depositing the H film layer and the L film layer in sequence and repeating a times. (2H)^b means depositing the H film layer and the H film layer in sequence and repeating b times, that is, the H film layer is repeated 2b times. (LH)^c means depositing the L film layer and the H film layer in sequence and repeating c times. (2L)^d means depositing the L film layer and the L film layer in sequence and repeating d times, that is, the L film layer is repeated 2d times. The H film layer represents a high refractive index film layer, and the high refractive index film layer includes a high refractive index material. The L film layer represents a low refractive index film layer, and the low refractive index film layer includes a low refractive index material. A high refractive index film layer is paired with an adjacent low refractive index film layer to form a high-low dual unit. Therefore, (HL)^a represents a high-low dual units, and (LH)^c represents c high-low dual units. It should be further explained that the film layer unit (HL)^a, the film layer unit (2H)^b, the film layer unit (LH)^c and the film layer unit (2L)^d can together constitute a film stack as a whole, and ((HL)^a(2H)^b(LH)^c(2L)^d)^e means that the film stack (HL)^a(2H)^b(LH)^c(2L)^d) is repeated e times. fL means that the L film layer is repeated f times, that is, the L film layer is deposited f times in sequence.

[0032] The technical solution of this embodiment provides a film structure that can correct the film thickness uniformity of high-precision thin-film components and the relative ratio of the optical thicknesses of their high and low refractive index materials. By manufacturing the film structure as: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air, the film structure is more sensitive to the film material thickness ratio when the reference spectral characteristic peak wavelength is used, and the spectral characteristic peak of this film structure is insensitive to material heterogeneity. In addition, this film structure is a regular structure with a simple manufacturing method. While correcting the film thickness uniformity, it can also efficiently determine and correct the film thickness ratio distribution of high and low refractive index materials, ensuring the accuracy of the relative ratio of the optical thickness of the high and low refractive index materials.

[0033] Optionally, in the above film structure, 1≤a≤5, 1≤c≤5. Specifically, the values of a and c are both positive integers.

[0034] Exemplarily, when a=1, (HL)^a represents sequentially depositing an H film layer and an L film layer; when a=5, (HL)^a represents sequentially depositing an H film layer and an L film layer, and repeating this process 5 times, i.e., sequentially depositing an H film layer, an L film layer, an H film layer, an L film layer, an H film layer, an L film layer, an H film layer, an L film layer, an H film layer, an H film layer, and an L film layer. Similarly, when c=1, (LH)^c represents sequentially depositing an L film layer and an H film layer. When c=5, (LH)^c represents sequentially depositing an L film layer and an H film layer, and repeating this process 5 times, i.e., sequentially depositing an L film layer, an H film layer, an L film layer, an H film layer, an L film layer, an H film layer, an L film layer, an H film layer, an L film layer, an H film layer, an L film layer, and an H film layer.

[0035] Optionally, in the above film structure, 1≤b≤2, 1≤d≤2, 1≤e≤2, and 1≤f≤2, where b, d, e, and f are all positive integers.

[0036] For example, when b=1, (2H)^b means depositing an H film layer and an H film layer in sequence. When b=2, (2H)^b means depositing an H film layer and an H film layer in sequence and repeating it twice, that is, depositing an H film layer in sequence four times. Similarly, when d=1, (2L)^d means depositing an L film layer and an L film layer in sequence. When d=2, (2L)^d means depositing an L film layer and an L film layer in sequence and repeating it twice, that is, depositing an L film layer in sequence four times. When e=2, ((HL)^a(2H)^b(LH)^c(2L)^d)^e means that the film stack (HL)^a(2H)^b(LH)^c(2L)^d is repeated twice. Taking a=1, b=1, c=1, d=1, and e=2 as an example, ((HL)^a(2H)^b(LH)^c(2L)^d)^e indicates that an H film layer, an L film layer, an H film layer, an H film layer, an L film layer, an H film layer, an L film layer, and an L film layer are deposited in sequence. After that, the operation is repeated to form the above film stack again, that is, an H film layer, an L film layer, an H film layer, an H film layer, an L film layer, an H film layer, an L film layer, and an L film layer are deposited in sequence. When f=1, fL indicates that an L film layer is deposited. When f=2, fL indicates that an L film layer and an L film layer are deposited.

[0037] Optionally, the high refractive index material is any one of Ta2O5, TiO2, HfO2, ZrO2, sulfide and selenide. The low refractive index material is any one of SiO2, Al2O3 and MgF2. The substrate is made of glass or crystal, and the glass can be any one of K9 glass and quartz glass. It should be noted that the film system structure of this embodiment is not sensitive to the heterogeneity of the material and is suitable for the preparation of thin film elements containing heterogeneous materials commonly used in laser films such as hafnium oxide and zirconium oxide, and the wavelength designed in the film system can be arbitrarily selected according to the characteristics and requirements of the equipment used, and the numerical value is not specifically limited.

[0038] The embodiment of the present invention is also based on the above-mentioned film structure to design and manufacture a Lan WDM narrowband filter (an example of a thin film element).

[0039] Specifically, a Lan WDM narrowband filter with a half-width less than 4nm and a 40mm×40mm aperture was fabricated. Because the film system is highly sensitive to thickness, and to achieve spectral uniformity across the entire dimension, the thickness ratio and uniformity of the high- and low-refractive-index materials at any point within the filter were extremely stringent. To this end, a film structure, Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^cfL|Air, was first employed to simultaneously adjust the thickness ratio and uniformity of the high- and low-refractive-index materials. The substrate was a quartz substrate, the high-refractive-index material was Ta2O5, and the low-refractive-index material was SiO2. The film layer repetitions in this structure were: a=5, b=2, c=5, d=3, e=1, and f=1. The central wavelength of the thin-film component using this film structure was 1310nm.

[0040] Based on the same inventive concept, this embodiment can be applied to a method for manufacturing a membrane structure, which specifically includes:

[0041] Step 1: Provide a substrate.

[0042] Optionally, the substrate is made of glass or crystal, and the glass can be any one of K9 glass and quartz glass.

[0043] Step 2: According to the film structure, high refractive index material and low refractive index material are grown in sequence by physical vapor deposition.

[0044] Alternatively, by sequentially growing high and low refractive index dielectric film layers on any optical substrate using physical vapor deposition, the preparation of this film system can be easily achieved using conventional optical monitoring or crystal oscillator monitoring.

[0045] Among them, the membrane system structure is: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air. Sub is the substrate, Air is the output medium air, H is a high-refractive-index material with an optical thickness of 1 / 4 of the center wavelength, L is a low-refractive-index material with an optical thickness of 1 / 4 of the center wavelength, a, b, c, d, e, and f are all positive integers; (HL)^a means depositing the H film layer and the L film layer in sequence and repeating a times; (2H)^b means depositing the H film layer and the H film layer in sequence and repeating b times; (LH)^c means depositing the L film layer and the H film layer in sequence and repeating c times; (2L)^d means depositing the L film layer and the L film layer in sequence and repeating d times; ((HL)^a(2H)^b(LH)^c(2L)^d)^e means the film stack (HL)^a(2H)^b(LH)^c(2L)^d is repeated e times; fL means the L film layer is repeated f times.

[0046] The film structure manufacturing method of this embodiment is used to manufacture the film structure in the above embodiment, and the generated film structure is: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^cfL|Air, so as to achieve the correction of film thickness uniformity while ensuring the accuracy of the relative ratio of the optical thickness of the high refractive index material and the low refractive index material.

[0047] In the present invention, the relative thickness ratio of the high-refractive-index film layer and the low-refractive-index film layer is corrected by determining the wavelength shift corresponding to the wave peak.

[0048] Optionally, the above-mentioned step 2 can be specifically refined as follows: according to the film structure, a high-refractive index material and a low-refractive index material are sequentially grown by physical vapor deposition, and the relative thickness ratio coefficient of the high-refractive index material and the low-refractive index material is determined based on the bandwidth between the wavelength corresponding to the transmission peak on both sides of the central wavelength and the central wavelength, and when the optical thickness ratio of the high-refractive index material and the low-refractive index material deviates from 1:1, the relative thickness ratio of the high-refractive index material and the low-refractive index material is corrected. In other words, during the process of depositing the high-refractive index film layer (i.e., the H film layer) and the low-refractive index film layer (i.e., the L film layer), their spectral characteristics (specifically, the wavelength shift corresponding to the peak) are analyzed to correct the relative thickness ratio of the high-refractive index film layer and the low-refractive index film layer.

[0049] For example, refer to Figure 1, according to the membrane structure: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air uses physical vapor deposition to sequentially grow high-refractive-index Ta2O5 and low-refractive-index SiO2. The spectral curve corresponding to the film structure now has three main characteristic peaks. The bandwidth between the wavelengths corresponding to the transmission peaks on both sides of the central wavelength can be used to determine the relative thickness ratio of the high-refractive-index and low-refractive-index materials. When the bandwidths corresponding to the wavelengths corresponding to the central wavelength on the left and right sides are the same, the optical thickness ratio of the high-refractive-index and low-refractive-index materials can be determined to be 1:1. When the bandwidths are inconsistent, it is equivalent to the optical thickness ratio deviating from 1:1. In this case, the optical thickness ratio can be determined based on the difference between the two wavelengths. When the bandwidth on the left is wider, the optical thickness ratio of the low-refractive-index and high-refractive-index materials is less than 1. When the bandwidth on the right is wider, the optical thickness ratio of the low-refractive-index and high-refractive-index materials is greater than 1. Ultimately, the relative thickness ratio of the high-refractive-index and low-refractive-index materials is corrected. After this method was modified, a narrowband filter with a light aperture of 40mm×40mm and a bandwidth of 3.8nm was successfully produced on a production-equipped direct-monitoring coating device. The uniformity of the in-plane central wavelength was less than 0.25nm. The schematic diagram of the designed spectrum and the measured spectrum curve is shown in the figure. Figure 2 shown.

[0050] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations, and substitutions are possible for those skilled in the art without departing from the scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A membrane structure, characterized in that: The membrane structure is: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air; Where Sub is the substrate, Air is the output medium air, H is the high refractive index material with an optical thickness of 1 / 4 the center wavelength, L is the low refractive index material with an optical thickness of 1 / 4 the center wavelength, and a, b, c, d, e, and f are all positive integers; Wherein, (HL)^a means sequentially depositing an H film layer and an L film layer and repeating it a times; (2H)^b means sequentially depositing an H film layer and an H film layer and repeating it b times; (LH)^c means sequentially depositing an L film layer and an H film layer and repeating it c times; (2L)^d means sequentially depositing an L film layer and an L film layer and repeating it d times; ((HL)^a(2H)^b(LH)^c(2L)^d)^e means that the film stack (HL)^a(2H)^b(LH)^c(2L)^d is repeated e times; fL means that the L film layer is repeated f times; Among them, 1≤a≤5, 1≤c≤5; 1≤b≤2, 1≤d≤2, 1≤e≤2, 1≤f≤2.

2. The film structure according to claim 1, characterized in that: The high refractive index material is any one of Ta2O5, TiO2, HfO2, ZrO2, sulfide and selenide.

3. The film structure according to claim 1, characterized in that: The low refractive index material is any one of SiO2, Al2O3 and MgF2.

4. The film structure according to claim 1, characterized in that: The substrate is a quartz substrate, the high refractive index material is Ta2O5, and the low refractive index material is SiO2.

5. The film structure according to claim 4, characterized in that: a=5, b=2, c=5, d=3, e=1, f=1.

6. A method for manufacturing a membrane structure, characterized in that: include: providing a substrate; According to the film structure, a high refractive index material and a low refractive index material are sequentially grown by physical vapor deposition; Wherein, the film structure is: Sub|((HL)^a(2H)^b(LH)^c(2L)^d)^e(HL)^a(2H)^b(LH)^c fL|Air; Wherein, Sub is the substrate, Air is the output medium air, H is a high-refractive-index material with an optical thickness of 1 / 4 the center wavelength, L is a low-refractive-index material with an optical thickness of 1 / 4 the center wavelength, and a, b, c, d, e, and f are all positive integers; Wherein, (HL)^a means sequentially depositing an H film layer and an L film layer and repeating it a times; (2H)^b means sequentially depositing an H film layer and an H film layer and repeating it b times; (LH)^c means sequentially depositing an L film layer and an H film layer and repeating it c times; (2L)^d means sequentially depositing an L film layer and an L film layer and repeating it d times; ((HL)^a(2H)^b(LH)^c(2L)^d)^e means that the film stack (HL)^a(2H)^b(LH)^c(2L)^d is repeated e times; fL means that the L film layer is repeated f times; Among them, 1≤a≤5, 1≤c≤5; 1≤b≤2, 1≤d≤2, 1≤e≤2, 1≤f≤2.

7. The production method according to claim 6, characterized in that: According to the film structure, a high refractive index material and a low refractive index material are grown in sequence by physical vapor deposition. The relative thickness ratio coefficient of the high refractive index material and the low refractive index material is determined based on the bandwidth between the wavelength corresponding to the transmission peak on both sides of the central wavelength and the central wavelength. When the optical thickness ratio of the high refractive index material and the low refractive index material deviates from 1:1, the relative thickness ratio of the high refractive index material and the low refractive index material is corrected.

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