CN109321887B

CN109321887B - Device and method for monitoring and preparing large-size uniform film by utilizing multipoint reflectivity

Info

Publication number: CN109321887B
Application number: CN201811375130.8A
Authority: CN
Inventors: 苏德坦; 司曙光; 乔芳建; 谢飞; 李冬; 王兴超; 孙赛林; 徐海洋; 金睦淳; 候巍; 张昊达; 曹宜起
Original assignee: North Night Vision Technology Co Ltd
Current assignee: North Night Vision Technology Co Ltd
Priority date: 2018-11-19
Filing date: 2018-11-19
Publication date: 2020-09-01
Anticipated expiration: 2038-11-19
Also published as: CN109321887A

Abstract

The invention provides a device and a method for preparing a large-size uniform film by utilizing multipoint reflectivity monitoring, which are suitable for preparing the large-size uniform film on a large-size substrate by utilizing the multipoint reflectivity monitoring method. Compared with the traditional film coating method by adopting a thickness monitoring mode, the device and the method for preparing the large-size uniform film by adopting multipoint reflectivity monitoring more directly monitor the reflectivity change of each position of the large-size product in the film coating process, can solve the problem that the uniformity of the large-size product cannot be evaluated in the manufacturing process by single-point measurement, and improve the production efficiency.

Description

Device and method for monitoring and preparing large-size uniform film by utilizing multipoint reflectivity

Technical Field

The invention relates to the technical field of photomultiplier, in particular to a technology for preparing a uniform film layer on the surface of a large-size photocathode, and particularly relates to a device and a method for preparing a large-size uniform film by utilizing multipoint reflectivity monitoring.

Background

The preparation technology of the large-size uniform film is widely applied to the aspects of optical coating, material surface coating and the like, and related products relate to a plurality of fields of production and life of people. The preparation of the large-size film mostly adopts various methods of coating and vacuum coating. In practical use, the parameters required for many large-sized coated products are actually optical parameters such as reflectivity, transmittance, light absorption rate, and the like. The manufacturing process of the transparent and semitransparent films can be monitored by an optical means, and the method has the advantages that in-situ measurement can be performed, while the film thickness monitoring method commonly used by the existing coating equipment is to use a crystal oscillator wafer to perform film thickness monitoring, the method is non-in-situ relative measurement, and the substrate to be coated can be shielded when in-situ measurement is performed.

The multipoint in-situ optical monitoring technology makes it possible to monitor the product uniformity in the production and preparation process of large-size uniform film. In actual production, corresponding optical inspection is needed to be carried out on a part of the product subjected to film coating to verify whether the product meets the design requirements, and the optical performance of the product can be inspected while the product is produced by the multipoint in-situ optical monitoring technology.

Disclosure of Invention

The invention aims to provide a device and a method for preparing a large-size uniform film by utilizing multipoint reflectivity monitoring, which can directly monitor the reflectivity change of each position of a large-size product and solve the problem that the uniformity of the large-size product cannot be evaluated in the manufacturing process by single-point measurement.

In order to achieve the above object, the present invention provides an apparatus for preparing a large-sized uniform film by monitoring multipoint reflectivity, which is suitable for a product to be coated being a transparent or semitransparent material, and being still in a transparent or semitransparent state during coating, the apparatus comprising an evaporation chamber, a multipoint reflectivity testing device, a multi-path bidirectional optical fiber, a substrate, an evaporation source moving device and a control system, wherein:

the evaporation chamber is set to provide a required vacuum and temperature environment for film layer evaporation, the substrate is supported in the middle of the evaporation chamber through a substrate support, and the multipath bidirectional optical fiber and the evaporation source are respectively positioned above and below the substrate;

the multipoint reflectivity testing equipment is arranged outside the evaporation chamber and used for transmitting monochromatic light signals through the multipath bidirectional optical fibers and receiving corresponding multipath reflected light signals, so that the reflectivity of the tested object at different positions is calculated;

the evaporation source is used as a raw material for evaporation coating, and a film layer manufactured by the evaporation source has the characteristics of transparency or translucency; the evaporation source is fixed on the evaporation source moving device and moves synchronously with the evaporation source moving device;

the control system is arranged for determining a current reflectivity change rate Pn based on the initial value and the minimum value of the monitored multipoint reflectivity, driving the motion of the evaporation source moving device based on the comparison of the current reflectivity change rate Pn of each point and the target reflectivity Pre to control the evaporation source to move in a two-dimensional plane, complementing the position with a thin film layer, and finally preparing the uniform film layer.

In a further embodiment, the evaporation chamber is internally provided with a hole for the multi-path bidirectional optical fiber to pass through and fix, and the hole is sealed.

In a further embodiment, the multi-path bidirectional optical fiber is at least provided with more than 10 paths.

In a further embodiment, the substrate is a circular substrate, 13 monitoring sites are arranged in the process of evaporating the film layer, bidirectional optical fibers are correspondingly arranged respectively, wherein 9 monitoring sites are distributed in a 3 × 3 rectangular shape with the circular shape of the substrate as the center, and 4 monitoring sites are respectively located at the outer center of each rectangular side.

In a further embodiment, the monitoring sites form an axisymmetric distribution.

In a further embodiment, the evaporation source moving device comprises a fixed frame, a threaded rod, a motor and a rotating shaft.

In a further embodiment, the control system comprises a reflectivity calculation unit and an evaporation source movement control unit, wherein the reflectivity calculation unit is arranged to calculate the current reflectivity rate of change in the following manner:

recording the initial reflectance R1 first, and storing the initial reflectance R1 as a reflectance minimum R2;

then, monitoring a value R according to real-time recording of the reflectivity, judging the sizes of R and R2, and when R is smaller than R2, replacing R2 with the value of R, namely executing R2= R, otherwise, not covering, namely keeping R2 unchanged;

then obtaining and outputting the current reflectivity change rate Pn according to a reflectivity change rate Pn calculation formula;

the evaporation source motion control unit determines the film thickness of each monitoring site according to the comparison of the current reflectivity change rate Pn of each monitoring site, drives the motion of the evaporation source moving device according to the comparison result to control the evaporation source to move in a two-dimensional plane, complements the thinner position of the film, and compares the thinner position with the target reflectivity Pre to finally prepare a uniform film, wherein Pn = (R + R1-2R 2)/R1.

According to the disclosure of the present invention, there is also provided a method for preparing a large-sized uniform thin film using multipoint reflectivity monitoring, comprising the steps of:

step 1, setting a target reflectivity change rate Pre of film evaporation;

step 2, calibrating the multi-point reflectivity test equipment through the standard reflectivity sample wafer;

step 3, replacing the standard reflectivity sample wafer with the substrate, and preparing an evaporation source to start evaporation;

and 4, starting coating after the internal conditions of the evaporation chamber meet the coating requirements, recording the reflectivity of each monitoring site according to a set time interval in the coating process, driving the movement of an evaporation source moving device to control the evaporation source to move in a two-dimensional plane through the comparison of the current reflectivity change rate of each monitoring point and the comparison of the target reflectivity Pre, complementing the position with a thinner film layer, and finally preparing the uniform film layer.

Compared with the traditional film coating method by adopting a thickness monitoring mode, the device and the method for preparing the large-size uniform thin film by adopting multipoint reflectivity monitoring more directly monitor the reflectivity change of each position of the large-size product in the film coating process, can solve the problem that the uniformity of the large-size product cannot be evaluated in the manufacturing process by single-point measurement, improve the consistency of the product, improve the yield of the product, reduce the production and processing links and improve the production efficiency.

Drawings

The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a device for manufacturing large-sized thin films using multi-point reflectivity monitoring according to a preferred embodiment of the present invention.

Fig. 2A-2C are schematic diagrams of an evaporation source moving apparatus and the operation principle thereof according to a preferred embodiment of the invention.

FIG. 3 is a schematic diagram of a distribution of detection points in a multi-point reflectivity monitoring system in accordance with a preferred embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating the reflectivity variation of a specific product when a film is deposited thereon according to a preferred embodiment of the present invention.

FIG. 5 is a logic diagram illustrating the calculation of the reflectivity change rate of a product according to a preferred embodiment of the present invention.

FIG. 6 is a graph showing the magnitude of the reflectivity change rate at each monitored location during the coating process according to a preferred embodiment of the present invention.

FIG. 7 is a diagram illustrating the magnitude of the reflectivity change rate at each monitored location after the coating process is completed according to a preferred embodiment of the present invention.

Detailed Description

In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings.

In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any one implementation. In addition, some aspects of the present disclosure may be used alone, or in any suitable combination with other aspects of the present disclosure.

Referring to fig. 1 to 7, an apparatus for manufacturing a large-sized uniform film using multi-point reflectivity monitoring according to a preferred embodiment of the present invention is suitable for manufacturing a large-sized uniform film on a large-sized substrate using a multi-point reflectivity monitoring method. In the evaporation process, the real-time change rate of the reflectivity is determined by monitoring the reflectivity of a plurality of monitoring sites in real time, the weak position is supplemented by an evaporation source under the control of the comparison of each site, and the uniform evaporation of the whole film layer is completed by combining with the initially set preset value.

The apparatus for preparing a large-sized uniform film using multi-point reflectivity monitoring, which is suitable for a product to be coated being a transparent or semitransparent material while still being in a transparent or semitransparent state during coating, according to the embodiment shown in fig. 1 to 3, includes a multi-point reflectivity testing device 101, a multi-path bidirectional optical fiber 102, an evaporation chamber 103, a substrate 104 (especially a large-sized substrate), an evaporation source 105, an evaporation source moving device 106, and a control system 110.

And the evaporation chamber 103 is arranged to provide a required vacuum and temperature environment for film layer evaporation. As shown in fig. 1, the evaporation chamber 103 generally has a hole for the multi-path bidirectional optical fiber 102 to pass through and fix, and measures are taken to seal the hole accordingly.

The substrate 104 is supported at an intermediate position of the evaporation chamber 103 by a substrate holder 104A, and the multi-path bi-directional optical fiber 102 and the evaporation source 105 are located above and below the substrate 104, respectively.

The evaporation chamber is separated by a large-sized substrate 104 and a substrate holder 104A to ensure that a film layer is not deposited on the multi-path bi-directional optical fiber during the coating process.

The multipoint reflectivity testing device 101 is arranged outside the evaporation chamber, and is used for emitting monochromatic light signals through the multipath bidirectional optical fibers 102 and receiving corresponding multipath reflected light signals, so as to calculate the reflectivity of the object to be tested at different positions, for example, the reflectivity is converted into electric signals through the photoelectric testing module, and the reflectivity of the object to be tested at different positions is calculated (namely, the reflectivity monitoring value is obtained). And can be visually represented or transmitted.

Preferably, the multi-point reflectivity testing apparatus 101 can simultaneously implement the reflectivity testing and calculation of more than 2 monitoring points. The multi-point reflectivity testing device 101 can perform reflectivity testing of different monitoring points by time division multiplexing of the light source and the photoelectric testing module, so that the number of the monitoring points realized by the multi-point reflectivity testing device 101 is not limited by the number of the light source and the photoelectric testing module, but is limited by the number of the multi-path bidirectional optical fibers 102. In some embodiments, the number of monitoring points that can be implemented can reach tens or even hundreds.

The multi-path bidirectional optical fiber 102 may adopt an existing bidirectional conductive optical fiber, and realizes a function of guiding out an optical signal generated by the multi-point reflectivity testing device and guiding back a reflected optical signal.

The substrate 104 is used as a product to be coated, and the reflectivity of the substrate can change along with the change of the thickness of the film layer in the coating process.

The evaporation source 105 is configured to evaporate a raw material of a coating film, and a film layer formed by the evaporation source has a transparent or translucent characteristic. The evaporation source 105 is fixed to the evaporation source moving device 106 and moves synchronously therewith.

As shown in fig. 1, the evaporation source 105 is generally separated from the multi-path bidirectional optical fiber 102 by the large-sized substrate 104 and its supporting frame to prevent the evaporation source 105 from evaporating on the multi-path bidirectional optical fiber 102, thereby affecting the test result of the multi-point reflectivity test apparatus 101.

The evaporation source moving device 106 can realize arbitrary movement of the evaporation source in the evaporation chamber. As shown in fig. 2A-2C, the evaporation source moving device 106 realizes the arbitrary movement of the evaporation source in the evaporation chamber through the evaporation source holder 106A, the threaded rod 106B, the motor 106C, and the rotating shaft 106D. The rotating shaft 106D can be lifted (driven) to move in the z-axis direction in space. The evaporation source holder 106A and the threaded rod 106B are integrally fixed by welding or the like. When the motor 106C rotates, the threaded rod 106B can be driven to perform linear motion, so as to realize the motion of the evaporation source 105 in the r direction. The rotation shaft 106D can rotate in the horizontal direction, and when the rotation shaft 106D rotates, the evaporation source 105 is driven to rotate in the plane, thereby realizing the motion in the θ direction. The combination of the above motions enables arbitrary movement of the evaporation source 105 in the z, r, and θ directions, thereby enabling arbitrary movement of the evaporation source 105 in the evaporation chamber. The motor 106C is particularly preferably a stepper motor.

That is, when the motor 106C operates, the threaded rod 106B can be driven to move linearly, thereby realizing the linear movement of the evaporation source 105. The rotation shaft 106D can rotate in the horizontal direction, and when the rotation shaft 106D operates, the evaporation source 105 is driven to rotate in a plane. In combination with the operation of the motor 106C on the vertical and rotating shaft 106D, the evaporation source 105 can be moved arbitrarily in a two-dimensional plane in the coating equipment.

In some embodiments, as shown in fig. 3-7, for a large-sized substrate 104 with a circular shape, 13 reflectivity monitoring sites may be provided during the coating process, and two-way optical fibers may be correspondingly provided, wherein 9 reflectivity monitoring sites are distributed in 3 × 3 rectangles centered on the circular shape of the substrate, and 4 reflectivity monitoring sites are respectively located at the outer center of each rectangle side.

In some preferred embodiments, the monitoring sites disposed on the substrate 104 form an axisymmetric distribution to facilitate regular monitoring and uniform vapor deposition replenishment.

And the control system 110 is connected with the point reflectivity testing equipment 101 and the evaporation source moving device 106, and is configured to determine a current reflectivity change rate Pn based on the initial value and the minimum value of the monitored multipoint reflectivity, and drive the evaporation source moving device to move based on the comparison of the current reflectivity change rate Pn of each point and the comparison of the target reflectivity Pre so as to control the evaporation source to move in a two-dimensional plane, complement the thinner position of the film layer, and finally prepare a uniform film layer.

In some embodiments, as shown in fig. 4, not only the reflectivity initial value R1 and the reflectivity monitoring value R, but also the lowest point R2 exists in the reflectivity curve during the reflectivity monitoring process, so the reflectivity change rate P is calculated in a corresponding manner by the multi-point reflectivity testing apparatus 101. As shown in fig. 5, the initial reflectance R1 is recorded first, and R1 is stored as the lowest reflectance R2. And then, recording the reflectivity monitoring value R in real time, judging the sizes of R and R2, covering R2 with the value of R when R is smaller than R2, and obtaining and outputting the current reflectivity change rate Pn according to the formula reflectivity change rate Pn = (R + R1-2R 2)/R1. And then, judging the magnitude of R and R2 once every time when recording the current reflectivity R value, storing the R2 numerical value again, and finally outputting the current reflectivity change rate Pn.

In connection with the implementation flow shown in fig. 5, the control system 110 includes a reflectivity calculating unit and an evaporation source movement control unit, wherein the reflectivity calculating unit is configured to calculate the current reflectivity change rate according to the following manner:

In some embodiments, as shown in fig. 6, the reflectivity change rates Pn of the monitoring points are different in the coating process, so that the reflectivity change rates Pn of the positions need to be compared in the coating process, the film thickness of the positions needs to be determined, the positions of the evaporation sources 105 are moved according to the result, the positions with thinner films are complemented, and finally the film with better uniformity is prepared, as shown in fig. 7.

Referring to fig. 1, fig. 2A-2C, and fig. 5, the present disclosure further provides a method for preparing a large-sized uniform thin film by using multi-point reflectivity monitoring, comprising the following steps:

step 1, setting a target reflectivity change rate Pre of film evaporation;

In step 1, the change rate of the reflectivity of the coating target can be calculated by theoretical calculation based on the conditions of the large-size substrate 104, the evaporation source 105, the film thickness and the like through model calculation. For example, the calculation method proposed by Li Xiaofeng et al, university of Nanjing Phytology.

Before the reflectivity monitoring of the present invention is implemented, before the coating is started, a standard reflectivity sample wafer is further installed at each monitoring position of the position where the large-size substrate 104 is installed, and the multipoint reflectivity testing equipment 101 is calibrated. And then after the multipoint reflectivity testing equipment 101 is calibrated, taking out the standard reflectivity sample wafer, placing the large-size substrate 104 and the evaporation source 105, checking whether the evaporation source 105 and the multi-path bidirectional optical fiber 102 are isolated or not after the placement is finished, and finally starting a coating process.

After the internal conditions of the evaporation chamber 103 meet the coating requirements, coating is started. In some embodiments, the reflectivity change rate Pn values of each point are compared at certain intervals in the coating process, the position of the evaporation source is moved according to the comparison result, and the position with the lowest reflectivity change rate Pn is subjected to supplementary coating until each point reaches the coating target reflectivity change rate.

By the technical scheme, the device and the method for monitoring and preparing the large-size uniform film by utilizing the multipoint reflectivity have the following remarkable beneficial effects:

1) the invention adopts a multipoint reflectivity monitoring mode to prepare the large-size film, can conveniently carry out multipoint in-situ measurement on the performance of the product under the condition of not shielding the product, and monitors the film layer change of different positions of the product in real time;

2) the invention adopts a multipoint reflectivity monitoring mode to prepare the large-size film, can directly know the optical performance parameters and the film uniformity of the product in the preparation process, does not need to pass subsequent tests, and can judge whether the product meets the design requirements in the production process;

3) according to the invention, the uniformity of the film layer can be corrected by moving the position of the evaporation source in the film coating process according to the monitoring results of different positions of the large-size substrate;

4) the technology of the invention is taken as an integral solution, is suitable for manufacturing various large-size optical products, has perfect monitoring data in the production process and good uniformity of product film layers, and can improve the production efficiency and the yield of the optical products.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto.

Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. The utility model provides an utilize device of multiple spot reflectivity control preparation jumbo size even film, is applicable to and waits that the coating film product is transparent or translucent material, still is transparent or translucent state in the coating process simultaneously, characterized in that, the device includes evaporating chamber, multiple spot reflectivity test equipment, multichannel two-way optic fibre, basement, evaporation source mobile device and control system, wherein:

the evaporation chamber is set to provide a required vacuum and temperature environment for film layer evaporation, and the substrate is supported in the middle of the evaporation chamber through a substrate support;

2. The apparatus for preparing a large-sized uniform thin film using multi-point reflectivity monitoring as claimed in claim 1, wherein a hole for a plurality of bi-directional optical fibers to pass through and fix is provided in the evaporation chamber, and the hole is sealed.

3. The apparatus for preparing a large-sized uniform film using multi-point reflectivity monitoring as claimed in claim 1, wherein the plurality of bi-directional optical fibers are arranged in at least 10 passes.

4. The apparatus for preparing a large-sized uniform thin film using multi-spot reflectivity monitoring of claim 1, wherein the substrate is a circular substrate, 13 monitoring sites are provided during the deposition of the thin film, and the bidirectional optical fibers are correspondingly provided, wherein 9 monitoring sites are distributed in 3 × 3 rectangles centered on the circular substrate, and 4 monitoring sites are respectively located at the outer center of each rectangle.

5. The apparatus for preparing a large-sized uniform thin film using multi-point reflectivity monitoring as claimed in claim 4, wherein the monitoring sites are formed in an axisymmetric distribution.

6. The apparatus for preparing a large-sized uniform thin film using multi-spot reflectivity monitoring as claimed in claim 1, wherein the plurality of bi-directional optical fibers and the evaporation source are respectively located above and below the substrate.

7. The apparatus for preparing a large-sized uniform film using multi-spot reflectivity monitoring as claimed in any one of claims 1 to 6, wherein the control system comprises a reflectivity calculating unit and an evaporation source movement control unit, wherein the reflectivity calculating unit is configured to calculate a current reflectivity change rate in the following manner:

8. A method for preparing a large-sized uniform thin film based on the apparatus of any one of claims 1 to 7, comprising the steps of:

step 1, setting a target reflectivity change rate Pre of film evaporation;