A method for manufacturing a film uniformity correction baffle

Abstract

The application discloses a manufacturing method of a film uniformity correction baffle, which comprises the following steps: firstly, using a coating machine to evaporate a proper amount of film material on a K9 substrate; after the completion, using a detection instrument to detect the reflectivity of the substrate; and then converting the reflectivity into a film thickness. Different positions of the substrate will convert different film thickness values. Secondly, a space rectangular coordinate system is established to describe the film material evaporation source position, the substrate position and the movement mode, and the mathematical factors of the correction baffle placement plane. Thirdly, a mathematical model is established to calculate the width of the correction baffle, and the correction baffle is manufactured according to the width. Finally, the film thickness on each substrate is substantially the same, and the surface shape change amount of the optical product after coating meets the technical requirements. The method can save a large amount of manpower and material resources, and compared with other manufacturing methods, the calculation result is more accurate, the experiment times are less, the correction accuracy of the correction baffle is higher, and the process level is more advanced.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a thin film uniformity correction baffle, belonging to the field of optical thin film deposition. Background Technology

[0002] With the rapid development of vacuum coating technology, product requirements are gradually moving towards high precision and sophistication, and the requirements for product uniformity are becoming increasingly stringent. Film uniformity refers to the characteristic that the film thickness deposited on the substrate changes as the substrate's position changes within the vacuum chamber. It is an important indicator for evaluating the optical performance and film quality of a product.

[0003] The placement of critical components such as the electron gun within the coating equipment determines the basic uniformity of the film layer. However, this uniformity can deviate from the required specifications, necessitating adjustments. Currently, domestic and international manufacturers use correction baffles to compensate for product uniformity. Research reveals various methods for baffle fabrication, but in practice, most rely heavily on individual experience, lacking a comprehensive theoretical design methodology. This hinders intuitive analysis and calculation of uniformity characteristics, making baffle fabrication a time-consuming, labor-intensive, and cumbersome process requiring numerous experiments and improvements. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method for manufacturing a thin film uniformity correction baffle. By establishing a spatial mathematical theoretical model, the entire coating process is digitized, the uniformity changes during the coating process are explained intuitively, and the number of correction experiments is greatly reduced.

[0005] The technical solution of this invention is: a method for manufacturing a thin film uniformity correction baffle, comprising:

[0006] 1) Select 5 clean glass substrates, mount them radially on the coating fixture, distribute them evenly, and then hang the coating fixture on the workpiece tray of the coating machine.

[0007] 2) Place the film material to be evaporated into the coating machine, ensuring there are no correction baffles between the suspended coating fixture and the film material evaporation source; begin coating.

[0008] 3) After the coating is completed, remove the glass substrate, measure the reflectance of the coated glass substrate, and obtain the reflectance curve;

[0009] 4) Select the peak on the reflectance curve, convert the reflectance into film thickness using a spectrophotometer, and record the film thickness E of each substrate.

[0010] 5) Select a value J and calculate the film thickness difference Q = EJ;

[0011] 6) Establish a spatial rectangular coordinate system, with the origin being the intersection of the coating fixture and the evaporation source plane. Measure the positions of the evaporation source and each substrate in the spatial rectangular coordinate system and represent them using coordinates.

[0012] 7) Using the center of the coating fixture as the center and the length from the location of each substrate to the origin as the radius, divide the rotation trajectory of the coating fixture into 5 concentric circles;

[0013] 8) Divide the circumference of each concentric circle into N equal arc lengths;

[0014] 9) Calculate the arc length T that needs to be corrected based on the film thickness E and the N equally divided arc lengths;

[0015] 10) Within the established spatial rectangular coordinate system, arbitrarily select the plane P on which the correction baffle is placed;

[0016] 11) Select any position when the substrate is rotated, measure the coordinates A1-A5 of each substrate at this time, connect the centers of the 5 substrates with the center of the evaporation source G to form 5 spatial straight lines, and find the intersection points of the 5 spatial straight lines with the spatial plane P. There are 5 intersection points A6-A10 in total.

[0017] 12) Use the arc length T that needs to be corrected to correct the arc length, and then find another point B1-B5 on the corrected arc length based on the center of the circle and the coordinates A1-A5 of each substrate.

[0018] 13) Connect points B1-B5 with the center of the evaporation source G to form 5 spatial straight lines, and calculate the intersection points B6-B10 of these 5 spatial straight lines with plane P;

[0019] 14) Create a correction plate based on the coordinates of points A6-A10 and B6-B10.

[0020] The glass substrate used is a K9 glass substrate with a diameter of 25-35mm.

[0021] The workpiece disk is a workpiece disk that only revolves around the sun and does not rotate on its own axis.

[0022] The value J is less than the thickness of the smallest substrate among the 5 substrates.

[0023] The N ≥ 1000.

[0024] The calculation of the arc length T to be corrected based on the film thickness E and the N equally divided arc lengths includes: assuming the film thickness E is the sum of N unit thicknesses, dividing the film thickness E by the number of arc lengths N gives the unit thickness a, i.e., a = E / N; then calculating the film thickness difference Q and dividing it by a gives the number of arc lengths M on each concentric circle, i.e., M = Q / a; assuming the circumference is C, then the arc length T to be corrected is T = C × (M / N).

[0025] The process of creating a correction plate based on the coordinates of points A6-A10 and B6-B10 includes:

[0026] Mark the coordinates of points A6-A10 and B6-B10 on a two-dimensional plane baffle. Connect points A6-A10, B6-B10, A10-B10, and A6-B6 in sequence. The area enclosed by these points is the correction plate that has been made.

[0027] It also includes step 15), where the prepared correction plate is hung in a designated position to conduct a uniformity verification experiment.

[0028] The process of hanging the fabricated correction plate at a designated position and conducting a uniformity verification experiment includes: hanging the fabricated correction plate at a designated position, repeating steps 1)-4), calculating the new film thickness E°, and if E-E° = Q, then the second experimental result is relatively ideal; if E-E° > Q or E-E° < Q, i.e., E° ≠ J, then there is a difference between the actual experimental data and the ideal data; setting the Tooling value H, H is used to correct the data, H = (E-E°) / Q; then the actual arc length to be corrected T° = T / H, repeating steps 10)-14), performing secondary processing on the correction plate, and after processing, hanging it on the coating machine, and returning to step 1) to verify uniformity.

[0029] The advantages of this invention compared to the prior art are:

[0030] 1. Existing technologies are mostly based on experience and lack a complete set of theoretical calculations, while the calculation results of this invention are accurate and have sufficient theoretical basis;

[0031] 2. Based on the establishment of a theoretical calculation system, this invention introduces an arc length correction value to obtain the actual required length;

[0032] 3. This invention allows for intuitive analysis and calculation of uniformity characteristics, requires fewer experimental iterations, and saves significant manpower and resources. Attached Figure Description

[0033] Figure 1 This is a theoretical model diagram of the method of the present invention. Detailed Implementation

[0034] like Figure 1 As shown, a method for manufacturing a thin film uniformity correction baffle includes:

[0035] 1) Select 5 clean glass substrates, mount them radially on the coating fixture, distribute them evenly, and then hang the coating fixture on the workpiece tray of the coating machine.

[0036] 2) Place the film material to be evaporated into the coating machine, ensuring there are no correction baffles between the suspended coating fixture and the film material evaporation source; begin coating.

[0037] 3) After the coating is completed, remove the glass substrate, measure the reflectance of the coated glass substrate, and obtain the reflectance curve;

[0038] 4) Select the peak on the reflectance curve, convert the reflectance into film thickness using a spectrophotometer, and record the film thickness E of each substrate.

[0039] 5) Select a value J and calculate the film thickness difference Q = EJ;

[0040] 6) Establish a spatial rectangular coordinate system, with the origin being the intersection of the coating fixture and the evaporation source plane. Measure the positions of the evaporation source and each substrate in the spatial rectangular coordinate system and represent them using coordinates.

[0041] 7) Using the center of the coating fixture as the center and the length from the location of each substrate to the origin as the radius, divide the rotation trajectory of the coating fixture into 5 concentric circles;

[0042] 8) Divide the circumference of each concentric circle into N equal arc lengths;

[0043] 9) Calculate the arc length T that needs to be corrected based on the film thickness E and the N equally divided arc lengths;

[0044] 10) Within the established spatial rectangular coordinate system, arbitrarily select the plane P on which the correction baffle is placed;

[0045] 11) Select any position when the substrate is rotated, measure the coordinates A1-A5 of each substrate at this time, connect the centers of the 5 substrates with the center of the evaporation source G to form 5 spatial straight lines, and find the intersection points of the 5 spatial straight lines with the spatial plane P. There are 5 intersection points A6-A10 in total.

[0046] 12) Use the arc length T that needs to be corrected to correct the arc length, and then find another point B1-B5 on the corrected arc length based on the center of the circle and the coordinates A1-A5 of each substrate.

[0047] 13) Connect points B1-B5 with the center of the evaporation source G to form 5 spatial straight lines, and calculate the intersection points B6-B10 of these 5 spatial straight lines with plane P;

[0048] 14) Create a correction plate based on the coordinates of points A6-A10 and B6-B10.

[0049] The glass substrate used is a K9 glass substrate with a diameter of 25-35mm.

[0050] The workpiece disk is a workpiece disk that only revolves around the sun and does not rotate on its own axis.

[0051] The value J is less than the thickness of the smallest substrate among the 5 substrates.

[0052] The N ≥ 1000.

[0053] The calculation of the arc length T to be corrected based on the film thickness E and the N equally divided arc lengths includes: assuming the film thickness E is the sum of N unit thicknesses, dividing the film thickness E by the number of arc lengths N gives the unit thickness a, i.e., a = E / N; then calculating the film thickness difference Q and dividing it by a gives the number of arc lengths M on each concentric circle, i.e., M = Q / a; assuming the circumference is C, then the arc length T to be corrected is T = C × (M / N).

[0054] The process of creating a correction plate based on the coordinates of points A6-A10 and B6-B10 includes:

[0055] Mark the coordinates of points A6-A10 and B6-B10 on a two-dimensional plane baffle. Connect points A6-A10, B6-B10, A10-B10, and A6-B6 in sequence. The area enclosed by these points is the correction plate that has been made.

[0056] The experiment also includes step 15), where the fabricated correction plate is hung in a designated position for a uniformity verification experiment. This uniformity verification experiment involves: hanging the correction plate in the designated position, repeating steps 1)-4), calculating the new film thickness E°. If E - E° = Q, the second experimental result is considered ideal; if E - E° > Q or E - E° < Q (i.e., E° ≠ J), the actual experimental data differs from the ideal data. A Tooling value H is set, used to correct the data, H = (E - E°) / Q. The actual arc length to be corrected, T°, is T / H. Steps 10)-14) are repeated to perform secondary processing on the correction plate. After processing, the plate is hung on the coating machine, and the process returns to step 1) to verify uniformity.

[0057] Example

[0058] 1. A product with a diameter of 1100mm was coated on a 2500mm diameter coating machine. Five points were selected in the radial direction to coat a single layer of film and simulate the film thickness. The thickness is shown in Table 1.

[0059] Table 1. Fitted film thickness (nm) at various points without a uniformity correction plate.

[0060] Take point A1 A2 A3 A4 A5 Film thickness E 380.3 388.5 396.7 408.6 415.5 radius R 300mm 500mm 700mm 900mm 1100mm

[0061] 2. Select a value J, J = 360nm, and calculate the difference between A1-A5 and the value J, as shown in Table 2.

[0062] Table 2. Film thickness differences at various points (nm)

[0063]

[0064]

[0065] 3. Taking point A1 as an example, let N1 = 1000 and radius R1 = 300nm. The coordinates of point A1 at a certain moment are A1(0,300,1400). Establish the formula T1 = 2πR1·Q1 / E1, where E1 represents the film thickness at point A1. Using the arc length T1, a point A1 on the arc length, and radius R1, calculate the coordinates of another point B1 on the arc length, namely B1(98,283.5,1400). Similarly, the coordinates of points A2-A5 and B2-B5 can be calculated.

[0066] 4. Under the established mathematical theoretical model, by applying the formula for calculating the intersection of a line and a plane, the coordinates of A6 can be calculated as (314.28, 214.28, 1000). Similarly, the coordinates of B6 can be calculated as (384.28, 202.5, 1000). The length D1 = 69 can be calculated. Similarly, D2-D5 can be calculated.

[0067] 5. Based on D1-D5, make correction baffles, then hang them in the designated position on the coating machine and coat again. The thickness difference of each point after coating and the Tooling value are shown in Table 3.

[0068] Table 3. Film thickness differences and Tooling values ​​(nm) at various points

[0069]

[0070] 6. Taking point A1 as an example, the film thickness that needs to be corrected is 20.3 nm, but only 18.3 nm was actually corrected, indicating that the length D1 is too short. Therefore, the length of D1 needs to be increased. Based on N1 and the Tooling value H1, the corrected arc length T1 is obtained, and then D1 is corrected. Similarly, D2-D5 are corrected. After the correction is completed, the correction baffle is made again to complete the experiment.

[0071] 7. After the experiment was completed, the film thickness at each point was shown in Table 4.

[0072] Table 4 shows the final fitted film thickness (nm) at each point using the uniformity correction plate.

[0073] Take point A1 A2 A3 A4 A5 Film thickness E 359 365 364 363 365

[0074] result:

[0075] The film thickness uniformity is calculated as follows:

[0076] Maximum film thickness difference = thickest film thickness - thinnest film thickness

[0077] Central film thickness = (maximum film thickness + minimum film thickness) ÷ 2

[0078] Film thickness uniformity = (maximum film thickness difference ÷ center film thickness) × 100%

[0079] Without the baffle, the film thickness uniformity S = 8.8%.

[0080] After using the correction baffle, the film thickness uniformity S0 = 1.6%.

[0081] Conclusion: Within the 1100mm diameter range, the uniformity S improved from 8.8% to 1.6%.

[0082] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention based on the above-disclosed technical content without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for manufacturing a thin film uniformity correction baffle, characterized in that, include: 1) Select 5 clean glass substrates, mount them radially on the coating fixture, distribute them evenly, and then hang the coating fixture on the workpiece tray of the coating machine. 2) Place the film material to be evaporated into the coating machine, ensuring there are no correction baffles between the suspended coating fixture and the film material evaporation source; begin coating. 3) After the coating is completed, remove the glass substrate, measure the reflectance of the coated glass substrate, and obtain the reflectance curve; 4) Select the peak on the reflectance curve, convert the reflectance into film thickness using a spectrophotometer, and record the film thickness E of each substrate. 5) Select a value J and calculate the film thickness difference Q = EJ; 6) Establish a spatial rectangular coordinate system, with the origin being the intersection of the coating fixture and the evaporation source plane. Measure the positions of the evaporation source and each substrate in the spatial rectangular coordinate system and represent them using coordinates. 7) Using the center of the coating fixture as the center and the length from the location of each substrate to the origin as the radius, divide the rotation trajectory of the coating fixture into 5 concentric circles; 8) Divide the circumference of each concentric circle into N equal arc lengths; 9) Calculate the arc length T that needs to be corrected based on the film thickness E and the N equally divided arc lengths; 10) Within the established spatial rectangular coordinate system, arbitrarily select the plane P on which the correction baffle is placed; 11) Select any position when the substrate is rotated, measure the coordinates A1-A5 of each substrate at this time, connect the centers of the 5 substrates with the center of the evaporation source G to form 5 spatial straight lines, and find the intersection points of the 5 spatial straight lines with the spatial plane P. There are 5 intersection points A6-A10 in total. 12) Use the arc length T that needs to be corrected to correct the arc length, and then find another point B1-B5 on the corrected arc length based on the center of the circle and the coordinates A1-A5 of each substrate. 13) Connect points B1-B5 with the center of the evaporation source G to form 5 spatial straight lines, and calculate the intersection points B6-B10 of these 5 spatial straight lines with plane P; 14) Based on the coordinates of points A6-A10 and B6-B10, create a correction template, specifically including: Mark the coordinates of points A6-A10 and B6-B10 on a two-dimensional plane baffle. Connect points A6-A10, B6-B10, A10-B10, and A6-B6 in sequence. The area enclosed by these points is the correction plate that has been made. The step of calculating the arc length T to be corrected based on the film thickness E and the N equally divided arc lengths includes: assuming that the film thickness E is the sum of N unit thicknesses, the unit thickness a = E / N is calculated; then the number of arc lengths on each concentric circle is M = Q / a; assuming the circumference is C, the arc length T to be corrected is T = C × (M / N). The value J is less than the minimum substrate thickness among the five substrates; The N ≥ 1000.

2. The method for manufacturing a thin film uniformity correction baffle according to claim 1, characterized in that, The glass substrate used is a K9 glass substrate with a diameter of 25-35mm.

3. The method for manufacturing a thin film uniformity correction baffle according to claim 1, characterized in that, The workpiece disk is a workpiece disk that only revolves around the sun and does not rotate on its own axis.

4. The method for manufacturing a thin film uniformity correction baffle according to claim 1, characterized in that, It also includes step 15), where the prepared correction plate is hung in a designated position to conduct a uniformity verification experiment.

5. The method for manufacturing a thin film uniformity correction baffle according to claim 4, characterized in that, The process of hanging the fabricated correction plate at a designated position and conducting a uniformity verification experiment includes: hanging the fabricated correction plate at a designated position, repeating steps 1)-4), calculating the new film thickness E°, and if E-E° = Q, then the second experimental result is relatively ideal; if E-E° > Q or E-E° < Q, i.e., E° ≠ J, then there is a difference between the actual experimental data and the ideal data; setting the Tooling value H, H is used to correct the data, H = (E-E°) / Q; then the actual arc length to be corrected T° = T / H, repeating steps 10)-14), performing secondary processing on the correction plate, and after processing, hanging it on the coating machine, and returning to step 1) to verify uniformity.

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