A method for controlling the thickness of a multilayer film

Abstract

The application provides a kind of multilayer film thickness control method, which is based on vacuum coating machine, vacuum coating machine includes evaporation system, umbrella frame and the correction version between evaporation system and umbrella frame;Correction version includes first correction version, second correction version and third correction version;Mainly include: first, substrate glass product is placed in clamp, then clamp is placed in the hollow place of umbrella frame, start evaporation source, and make electron beam into coating material, so that coating material is evaporated by electron beam and deposited on the surface of substrate glass product through first correction version, then the evaporation source of evaporation system is closed to complete the first coating;Second, replace first correction version with second correction version, and carry out second coating;Finally, replace second correction version with third correction version, and carry out third coating.The application has reasonable concept, simple process, can effectively control the uniformity of product coating, significantly improve the performance and yield of product, coating material loss is low, and can meet the coating product with higher precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optoelectronic technology, and in particular to a method for controlling the thickness of a multilayer film. BACKGROUND

[0002] A multilayer film filter has A surface for filtering light, and the number of layers is generally more than 40, and the thickness is more than 5 um, such as an infrared cutoff film, a narrowband film, a dual-channel film, etc. The B surface is generally antireflection, and the number of layers is generally about 10, and the thickness is about 0.3 um, and the maximum thickness is generally not more than 0.5 um. Because the thickness of the A surface and the B surface is too different (for example, the thickness of the A surface is 10 times the thickness of the B surface, i.e., 50 um is the thickness of the A surface and 0.5 um is the thickness of the B surface), after the substrate is coated, the products seriously warp each other: the A surface with a large thickness will "arch up". During the film forming process, the greater the thickness of the deposited film, the more serious the "arching up" will be, resulting in the occurrence of non-uniform film in the point area and the peripheral area of the product.

[0003] Taking a glass substrate with a thickness of 0.21 as an example, the size is 77 mm*77 mm, and an infrared cutoff filter is made: the A surface is made of 45 layers of infrared cutoff film with a thickness of about 5 um, and the B surface is made of 7 layers of visible light antireflection film with a thickness of about 0.3 um. After the product is coated, the A surface "arches up" with a height of about 3 mm.

[0004] A 1.5-meter coating machine, the distance from the evaporation source to the position directly above the substrate is about 1000 mm; when the A surface is about to be coated, the distance between the point of "arching up" and the evaporation point increases to 1003 mm. The evaporation source is regarded as a point light source, which emits light according to a certain divergence angle, and the vertical line of the evaporation source and the substrate is regarded as the vertical axis and the horizontal line, and the substrate is horizontally placed on the umbrella frame. Let a represent the film thickness obtained when the distance is 1000 mm (the edge of the product), and b represent the film thickness obtained when the distance is 1003 mm (the point of "arching up"), according to the basic formula of object illumination, a:b=(1003:1000) 2 ≈1.006, i.e., after arching up by 3 mm, the film thickness decreases by 0.6%; i.e., during the entire coating process, the non-uniformity of the center point of the product gradually increases from 0 to 0.6%, and the average value of the non-uniformity of the center point is (0+0.6%) / 2=0.3%. In many multilayer film systems with high sensitivity, the influence of 0.3% is sometimes fatal.

[0005] The prior art is generally plated at one time, and has the advantage of high efficiency, but the "innate" 0.3% non-uniformity cannot be eliminated; some sensitive film systems sometimes only allow 0.3% uniformity at most, and other factors affect the overall uniformity error to 0.5%~1.0%, so that the performance of the good product cannot be guaranteed; in actual production process, some manufacturers cannot determine how many performance good products are in a furnace, and can only be 100% detected after plating, and only the performance of the qualified product can be output to the next work station, so that the loss is high, the uncertainty is high, and the actual production is difficult to control.

[0006] In summary, it is necessary to further innovate the prior art. SUMMARY

[0007] In view of the technical problems in the above background art, the present application provides a multi-layer film thickness control method, which has reasonable concept and simple process, can effectively control the uniformity of product plating film, significantly improve the performance and yield of product, has low plating film loss, and can meet the plating film products with higher precision.

[0008] To solve the above technical problems, the present application provides a multi-layer film thickness control method based on a vacuum plating machine, wherein the vacuum plating machine comprises an evaporation system, a matching umbrella frame located above the evaporation system, and a modified version matched between the evaporation system and the umbrella frame; the modified version comprises a first modified version, a second modified version and a third modified version; and the method mainly comprises the following steps:

[0009] (1) first place a substrate glass product in a clamp of the vacuum plating machine, then place the clamp in a hollow part of the umbrella frame, start the evaporation source of the evaporation system, and hit the electron beam into the plating film material, so that the plating film material is evaporated by the electron beam and then deposited onto the surface of the substrate glass product through the first modified version, and then the evaporation source of the evaporation system is turned off to complete the first plating;

[0010] (2) replace the first modified version with the second modified version, and the edge of the second modified version is concave relative to the edge of the first modified version, then start the evaporation source of the evaporation system again, hit the electron beam into the plating film material, so that the plating film material is evaporated by the electron beam and then deposited onto the surface of the substrate glass product again through the second modified version, and then the evaporation source of the evaporation system is turned off to complete the second plating;

[0011] (3) replace the second modified version with the third modified version, and the edge of the third modified version is concave relative to the edge of the second modified version, then start the evaporation source of the evaporation system again, hit the electron beam into the plating film material, so that the plating film material is evaporated by the electron beam and then deposited onto the surface of the substrate glass product again through the third modified version, and then the evaporation source of the evaporation system is turned off to complete the third plating.

[0012] The method for controlling the thickness of the multilayer film, wherein: before the film coating starts, the planes of the first, second and third modified versions are divided to ensure that the most coating material is at the middle of the first, second and third modified versions during the film coating, and the coating material at the positions on both sides of the middle position decreases in turn.

[0013] The method for controlling the thickness of the multilayer film, wherein: when the planes of the first, second and third modified versions are divided, the thickness deviation of the adjacent positions is controlled within 0.5%.

[0014] The method for controlling the thickness of the multilayer film, wherein: in the step (1), the glass substrate product is coated for the first time at a temperature of 120-180°C and a vacuum degree of 1.0E-3-3.0E-3; during the first coating, the vacuum degree is 1.5E-2-2.5E-2 when coating the high refractive material, and 1.0E-2-2.0E-2 when coating the low refractive material; after the first coating, the center of the glass substrate product is raised by 1 mm; at this time, the center point non-uniformity of the glass substrate product increases from 0 to 0.2%, and the average value of the center point non-uniformity of the glass substrate product after the first coating is 0.1%.

[0015] The method for controlling the thickness of the multilayer film, wherein: in the step (2), the glass substrate product is coated for the second time at a temperature of 120-180°C and a vacuum degree of 1.0E-3-3.0E-3; during the second coating, the vacuum degree is 1.5E-2-2.5E-2 when coating the high refractive material, and 1.0E-2-2.0E-2 when coating the low refractive material; after the second coating, the center of the glass substrate product is raised by 2 mm; at this time, the center point non-uniformity of the product increases from 0 to 0.2%, and the average value of the center point non-uniformity of the glass substrate product after the second coating is 0.1%.

[0016] The method for controlling the thickness of the multilayer film, wherein: in the step (2), the edge of the second modified version is recessed inward by 0.2-2.0 mm relative to the edge of the first modified version.

[0017] The thickness control method of the multilayer film, wherein: in the step (3), the glass substrate product is plated for the third time at a plating temperature of 120-180 DEG C and an opening plating vacuum degree of 1.0E-3-3.0E-3; during the third plating, the vacuum degree is 1.5E-2-2.5E-2 when plating the high-refractive material; during the third plating, the vacuum degree is 1.0E-2-2.0E-2 when plating the low-refractive material; after the third plating, the center arch height of the substrate glass product increases to 3 mm, and the center point non-uniformity of the substrate glass product increases from 0 to 0.2%; and after the plating of the substrate glass product is completed, the average value of the center point non-uniformity of the substrate glass product is 0.1%.

[0018] The thickness control method of the multilayer film, wherein: in the step (3), the edge of the third modified version is also recessed inward by 0.2-2.0 mm relative to the edge of the second modified version.

[0019] The thickness control method of the multilayer film, wherein: the electron beam of the evaporation source of the evaporation system is shot into the plating material at a power of 5000-8000 W.

[0020] The thickness control method of the multilayer film, wherein: the evaporation source of the evaporation system is matched and placed at a position 1000 m away from the center point of the umbrella frame.

[0021] By adopting the technical scheme, the present application has the following beneficial effects:

[0022] The thickness control method of the multilayer film has reasonable conception and simple flow, can effectively control the uniformity of the product plating, significantly improve the performance and yield of the product, has low plating material loss, and can meet the plating products with higher precision.

[0023] The present application can reduce the product plating non-uniformity from 0.3% to 0.1%, and in some narrow-band optical filter plating, some high-requirement thin films require 0.1% uniformity, which generally needs to be made by direct light control; however, the present application can be made by indirect light control, thereby reducing the cost and plating equipment modification caused by the direct light control; in addition, even if a high-precision control method is adopted, the uniformity of the center point and the edge cannot be considered when the area of the optical element is large, and the present application can effectively solve this problem and improve the use area of the optical element. BRIEF DESCRIPTION OF DRAWINGS

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This diagram illustrates the significance of the location of a vacuum coating machine in the multilayer thin film thickness control method of the present invention.

[0026] Figure 2 This is a diagram showing the substrate glass product mounted on an umbrella frame in the multilayer thin film thickness control method of the present invention.

[0027] Figure 3 This is a top view of a modified version of the multilayer thin film thickness control method of the present invention;

[0028] Figure 4 This is a schematic diagram of the structural state of the first modified version and the coated product during the first coating process in the multilayer thin film thickness control method of the present invention;

[0029] Figure 5 This is a schematic diagram of the structural state of the second modified version and the coated product during the second coating process in the multilayer thin film thickness control method of the present invention;

[0030] Figure 6 This is a schematic diagram of the structural state of the third revised version and the coated product during the third coating process in the multilayer thin film thickness control method of the present invention. Detailed Implementation

[0031] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The present invention will be further explained below with reference to specific embodiments.

[0033] like Figure 1 As shown, this embodiment provides a method for controlling the thickness of a multilayer thin film, based on a vacuum coating machine. The vacuum coating machine includes an evaporation system, a matching umbrella frame 2 located directly above the evaporation system, and a modified version 4 located between the evaporation system and the umbrella frame 2. The modified version 4 includes a first modified version, a second modified version, and a third modified version.

[0034] This embodiment involves depositing 45 layers of film in three stages, specifically including the following steps:

[0035] S100, First Coating

[0036] First, place the substrate glass product 1 in the fixture of the vacuum coating machine, and then place the fixture in the cutout of the umbrella frame 2 (e.g., Figure 2 As shown), the evaporation source 3 of the evaporation system is placed 1000m away from the center point of the umbrella frame 2; as shown Figure 1 and Figure 3 The first revised version of the plane is divided into seven regions, namely positions 1#-7#, for correction. Position 4# of the first revised version has the most coating material, and the coating material of positions 3#-1# decreases sequentially, and the coating material of positions 4#-7# decreases sequentially. Therefore, position 4# of the first revised version covers the largest area, and the area of ​​other positions decreases sequentially. In this way, the thickness of the coating material of positions 1#-7# in the first revised version tends to be consistent, and the thickness deviation is controlled within 0.5%.

[0037] Depositing 15 layers of film: such as Figure 1 As shown, the evaporation source 3 of the evaporation system is started, and an electron beam is injected into the coating material with a certain energy (5000W-8000W). After the coating material is evaporated by the electron beam, it is deposited on the surface of the substrate glass product 1. Then, the evaporation source 3 of the evaporation system is turned off. During the first coating, the coating temperature is between 120℃ and 180℃, and the vacuum degree is between 1.0E-3 and 3.0E-3. During the first coating, when coating high refractive index materials, the vacuum degree is between 1.5E-2 and 2.5E-2. During the first coating, when coating low refractive index materials, the vacuum degree is between 1.0E-2 and 2.0E-2. After the first coating, the center of the substrate glass product 1 is raised by 1mm. At this time, the center point non-uniformity of the substrate glass product 1 increases from 0 to 0.2%. After the substrate glass product 1 is coated, the average center point non-uniformity of the substrate glass product 1 is (0+0.2%) / 2=0.1%, that is, the average uniformity of the first 15 layers is 0.1%.

[0038] The average non-uniformity at the center point of the aforementioned substrate glass product 1 is mainly calculated using the illuminance formula. Illuminance is inversely proportional to the square of the distance from the light source. The evaporation source 3 is considered the light source, and the calculation is performed accordingly: see... Figure 11.5m coater, the distance from evaporation source 3 to the position of the substrate glass product 1 is about 1000mm; when the A surface of the substrate glass product 1 is finished being coated, the distance from the point where the substrate glass product 1 "bends up" to the evaporation point increases to 1003mm. The evaporation source 3 is regarded as a point light source, which emits light according to a certain divergence angle, and the direction of movement of the evaporated coating material is perpendicular to the surface of the substrate glass product 1, which is horizontally placed on the umbrella frame 2; let a represent the film thickness obtained when the distance is 1000mm (the edge of the substrate glass product 1), and let b represent the film thickness obtained when the distance is 1003mm, i.e. the point where the substrate glass product 1 bends up; according to the basic formula of object illumination, a:b=(1003:1000)2≈1.006, i.e. after the substrate glass product 1 bends up by 3mm (as shown in Figure 4 , the film thickness decreases by 0.6%; i.e. during the entire coating process, the non-uniformity of the center point of the substrate glass product 1 gradually increases from 0 to 0.6%, and the average value of the non-uniformity of the center point of the substrate glass product 1 is (0+0.6%) / 2=0.3%. In many multi-layer thin film systems with high sensitivity, the influence of this 0.3% can be fatal.

[0039] S200, second coating

[0040] The first modified version is replaced by a second modified version (with a different shape than the first modified version), and the substrate glass product 1 is modified according to the 1mm bending height generated by the first coating (as shown in Figure 5 , the plane of the second modified version is divided into seven areas, and the positions of 1#~7# of the second modified version are "concave" relative to the edges of the first modified version; the reason is that the product bends, and the received coating material is about 0.1% less, so the edges of the second modified version (i.e. the seven areas) are concave relative to the edges of the first modified version by 0.2mm~2.0mm, so that the center point of each area obtains "more" coating material, thereby balancing the 0.1% non-uniformity.

[0041] Coating 15 layers of film: as shown in Figure 1, the evaporation source 3 of the evaporation system is started, and the electron beam is shot into the coating material at a certain energy (5000W-8000W); the coating material is evaporated by the electron beam and deposited on the surface of the substrate glass product 1, and then the evaporation source 3 of the evaporation system is turned off; in the second coating, the coating temperature is between 120-180℃, and the coating vacuum degree is between 1.0E-3-3.0E-3; in the second coating process, when coating high refractive index material, the vacuum degree is between 1.5E-2-2.5E-2; in the second coating process, when coating low refractive index material, the vacuum degree is between 1.0E-2-2.0E-2; after the second coating, the center point of the substrate glass product 1 increases by 1mm, that is, the product increases by 2mm, and at this time, the center point of the substrate glass product 1 increases from 0 to 0.2%, and the average value of the center point of the substrate glass product 1 after the second coating is (0+0.2%) / 2=0.1%, that is, the average uniformity of the middle 15 layers is 0.1%. The second modified version is modified according to the current state of the center point of the substrate glass product 1, and the center point of the substrate glass product 1 increases with the increase of the coating layer, but the modified version cannot follow the movement. Therefore, assuming that the uniformity of the initial state of the modified version is 0%, after coating the 15 layers, the modified version cannot cover the glass due to the increase of the glass arch height, and at this time, the instantaneous uniformity is 0.2%; that is, the uniformity increases from 0 to 0.2%, which increases gradually to a certain extent.

[0042] S300, third coating

[0043] The second modified version is replaced by a third modified version (different from the first modified version and the second modified version), and the center point of the substrate glass product 1 is modified according to the 1mm arch height generated by the second coating; the plane of the third modified version is divided into seven areas, and the positions of the third modified version from 1# to 7# are concave by 0.2mm-2.0mm relative to the second modified version.

[0044] Coating 15 layers: start the evaporation source 3 of the evaporation system, and the electron beam is shot into the coating material at a certain energy (5000W-8000W); the coating material is evaporated by the electron beam and deposited on the surface of the substrate glass product 1, and then the evaporation source 3 of the evaporation system is turned off. Among them, in the third coating, the coating temperature is between 120-180℃, and the coating vacuum degree is between 1.0E-3-3.0E-3; in the third coating process, when coating high refractive index material, the vacuum degree is between 1.5E-2-2.5E-2; in the third coating process, when coating low refractive index material, the vacuum degree is between 1.0E-2-2.0E-2; after the third coating, the center point of the substrate glass product 1 increases by 1mm, that is, the product increases by 3mm (such as Figure 6As shown in the table, the center point non-uniformity of the substrate glass product 1 increases from 0 to 0.2% when the first 15 layers are plated, and the average center point non-uniformity of the substrate glass product 1 after the substrate glass product 1 is plated is (0+0.2%) / 2=0.1%, i.e. the average uniformity of the last 15 layers is 0.1%.

[0045] In the table, since the average uniformity of the first 15 layers, the middle 15 layers and the last 15 layers is all 0.1%, i.e. the uniformity of the whole film system is controlled at 0.1%; by the method of the present application, the non-uniformity is reduced from 0.3% to 0.1%.

[0046] The present application has reasonable concept and simple process, and can effectively control the uniformity of the product plating film, significantly improve the performance and yield of the product, has low plating film material loss, and can meet the plating film products with higher precision.

[0047] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that: they can still modify the technical solutions recorded in the above embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for controlling the thickness of a multi-layer film based on a vacuum coater, the vacuum coater comprising an evaporation system, a matching umbrella frame located directly above the evaporation system, and a correction plate matching located between the evaporation system and the umbrella frame; the correction plate comprising a first correction plate, a second correction plate, and a third correction plate; characterized in that, The method comprises the following steps: (1) first, the substrate glass product is placed in the clamp of the vacuum coating machine, then the clamp is placed in the hollow part of the umbrella stand, the evaporation source of the evaporation system is started, the electron beam is shot into the coating material, the coating material is evaporated by the electron beam and then deposited on the surface of the substrate glass product through the first correction plate, then the evaporation source of the evaporation system is turned off, so as to complete the first coating; (2) the first correction plate is replaced by the second correction plate, the edge of the second correction plate is concave relative to the edge of the first correction plate, the evaporation source of the evaporation system is started again, the electron beam is shot into the coating material, the coating material is evaporated by the electron beam and then deposited on the surface of the substrate glass product through the second correction plate, then the evaporation source of the evaporation system is turned off, so as to complete the second coating; (3) the second correction plate is replaced by the third correction plate, the edge of the third correction plate is concave relative to the edge of the second correction plate, the evaporation source of the evaporation system is started again, the electron beam is shot into the coating material, the coating material is evaporated by the electron beam and then deposited on the surface of the substrate glass product through the third correction plate, then the evaporation source of the evaporation system is turned off, so as to complete the third coating.

2. The method of claim 1, wherein: Before coating, the plane of the first correction plate, the second correction plate and the third correction plate is divided, so as to ensure that the coating material in the middle position of the first correction plate, the second correction plate and the third correction plate is the most, and the coating material in the positions on both sides of the middle position is reduced in turn.

3. The method for controlling the thickness of multilayer thin films as described in claim 2, characterized in that: When the plane of the first correction plate, the second correction plate and the third correction plate is divided, the thickness deviation of adjacent positions is controlled within 0.5%.

4. The method of claim 1, wherein: In the step (1), the coating temperature of the glass substrate product in the first coating is between 120 DEG C and 180 DEG C, and the coating vacuum degree is between 1.0E-3 and 3.0E-3; in the first coating process, when coating high refractive index material, the vacuum degree is between 1.5E-2 and 2.5E-2; in the first coating process, when coating low refractive index material, the vacuum degree is between 1.0E-2 and 2.0E-2; after the first coating, the center of the substrate glass product is arched by 1 mm; at this time, the center point non-uniformity of the substrate glass product increases from 0 to 0.2%, and the average value of the center point non-uniformity of the substrate glass product after the first coating is 0.1%.

5. The method of claim 1, wherein: the first and second layers are formed by a process selected from the group consisting of: spin coating, dip coating, spray coating, and combinations thereof. In the step (2), the coating temperature of the glass substrate product in the second coating is between 120 DEG C and 180 DEG C; the coating vacuum degree is between 1.0E-3 and 3.0E-3; in the second coating process, when coating high refractive index material, the vacuum degree is between 1.5E-2 and 2.5E-2; in the second coating process, when coating low refractive index material, the vacuum degree is between 1.0E-2 and 2.0E-2; after the second coating, the center of the substrate glass product is arched by 2 mm, at this time, the center point non-uniformity of the product increases from 0 to 0.2%, and the average value of the center point non-uniformity of the substrate glass product after the second coating is 0.1%.

6. The method of claim 1, wherein: The edge of the second correction plate in the step (2) is recessed inwardly relative to the edge of the first correction plate by 0.2mm-2.0mm.

7. The method of claim 1, wherein: the thickness of the multilayer film is controlled by the step of: In the third coating process in the step (3), the coating temperature is 120-180℃, and the opening coating vacuum degree is 1.0E-3-3.0E-3; in the third coating process, when coating the high refractive index material, the vacuum degree is 1.5E-2-2.5E-2; in the third coating process, when coating the low refractive index material, the vacuum degree is 1.0E-2-2.0E-2; after the third coating process, the center arch height of the substrate glass product is increased to 3mm, at this time, the center point non-uniformity of the substrate glass product is increased from 0 to 0.2%, and after the coating of the substrate glass product is completed, the average value of the center point non-uniformity of the substrate glass product is 0.1%. ​ 8. The method of claim 1, wherein: The edge of the third correction plate in the step (3) is also recessed inwardly relative to the edge of the second correction plate by 0.2mm-2.0mm.

9. The method of claim 1, wherein: The electron beam of the evaporation source of the evaporation system is shot into the coating material at a power of 5000W-8000W.

10. The method of claim 1, wherein: The evaporation source of the evaporation system is matched and placed at a position 1000m away from the center point of the umbrella frame.

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