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

Abstract

The invention provides a device and method for preparing a large-size uniform film by using multi-point reflectivity monitoring, which is suitable for preparing a large-size uniform film on a large-size substrate by using the multi-point reflectivity monitoring method. Real-time monitoring of reflectivity, determine the real-time rate of change of reflectivity, control the evaporation source to supplement weak positions through the comparison of each site, and combine the initial preset value to complete the uniformity of the entire film layer Evaporation. Compared with the traditional method of thickness monitoring for coating, the device and method for preparing large-size, uniform and thin films by using multi-point reflectivity monitoring of the present invention more directly monitor the reflectivity changes at various positions of large-size products during the coating process. It can solve the problem that single-point measurement cannot evaluate the uniformity of large-scale products in the manufacturing process, and improve production efficiency.

Description

Apparatus and method for preparing large-size uniform thin films by using multi-point reflectivity monitoring

technical field

The invention relates to the field of photomultiplier technology, in particular to a technology for preparing a large-size photocathode with a uniform surface film layer, and in particular to a device and method for preparing a large-size uniform film by using multi-point reflectivity monitoring.

Background technique

The preparation technology of large-size uniform thin films is widely used in optical coating, material surface coating, etc. The related products involve many fields of people's production and life. The preparation of large-size thin films mostly adopts various methods of coating and vacuum coating. In actual use, the parameters required for many large-scale coating products are actually optical parameters, such as reflectivity, transmittance, light absorption, and so on. For transparent and semi-transparent films, the production process can be monitored by optical means. The advantage is that in-situ measurement can be performed. However, the commonly used film thickness monitoring method for existing coating equipment is to use crystal oscillators for film thickness monitoring. In-situ relative measurement, which will block the substrate to be coated.

The multi-point in-situ optical monitoring technology makes it possible to monitor the product uniformity during the production and preparation of large-sized uniform films. And in actual production, some products that have finished coating also need to undergo corresponding optical inspection to verify whether the product meets the design requirements. The multi-point in-situ optical monitoring technology can perform optical performance inspection of the product at the same time of production.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a device and method for preparing large-size uniform thin films by using multi-point reflectivity monitoring, which can directly monitor the reflectivity changes at various positions of large-size products, and solve the problem that single-point measurement cannot evaluate large-size products during the manufacturing process. uniformity issue.

In order to achieve the above purpose, the present invention proposes a device for preparing a large-size uniform thin film by using multi-point reflectance monitoring, which is suitable for a product to be coated that is a transparent or semi-transparent material, and is still in a transparent or semi-transparent state during the coating process. The device includes an evaporation chamber, a multi-point reflectance test device, a multi-way bidirectional optical fiber, a substrate, an evaporation source, a moving device for the evaporation source, and a control system, wherein:

The evaporation chamber is set to provide the required vacuum and temperature environment for film evaporation, the substrate is supported in the middle position of the evaporation chamber by the substrate support, and the multi-way bidirectional optical fiber and the evaporation source are respectively located above and below the substrate;

The multi-point reflectivity test equipment set outside the evaporation chamber is used to transmit monochromatic light signals through the multi-channel bidirectional optical fibers and receive the corresponding multi-channel reflected light signals, thereby calculating the reflections of different positions of the measured object. Rate;

The evaporation source is constituted as a raw material for evaporation coating, and the film layer made 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 it;

The control system is configured to determine the current reflectivity change rate Pn based on the monitored initial and minimum values of reflectivity at multiple points, and based on the comparison of the current reflectivity change rate Pn at each point, and the target reflectance The comparison of the rate Pre is used to drive the movement of the evaporation source moving device to control the movement of the evaporation source in the two-dimensional plane, to complement the thin film layer, and finally to prepare a uniform film layer.

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

In a further embodiment, at least 10 channels of the multi-channel bidirectional optical fibers are provided.

In a further embodiment, the substrate is a circular substrate, and 13 monitoring sites are set during the process of evaporating the film layer, and bidirectional optical fibers are correspondingly set respectively, and 9 monitoring sites are 3* centered on the circle of the substrate. 3 rectangles are distributed, and 4 are 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 includes a fixing frame, a threaded rod, a motor and a rotating shaft.

In a further embodiment, the control system includes a reflectance calculation unit and an evaporation source motion control unit, wherein the reflectance calculation unit is configured to calculate the current reflectance change rate in the following manner:

First record the initial reflectivity R1, and store the initial reflectivity R1 as the lowest reflectivity value R2;

Then record the reflectance monitoring value R in real time, and judge the size of R and R2. When R is less than R2, use the value of R to replace R2, that is, execute R2=R, otherwise it is not covered, that is, keep R2 unchanged;

Then according to the calculation formula of the reflectivity change rate Pn, the current reflectivity change rate Pn is obtained and output;

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, and drives the movement of the evaporation source moving device according to the comparison result to control the evaporation source in two dimensions. In-plane movement, the thin film layer is supplemented, and compared with the target reflectivity Pre, a uniform film layer is finally prepared, where Pn=(R+R1-2R2)/R1.

According to the disclosure of the present invention, a method for preparing a large-size uniform thin film by using multi-point reflectivity monitoring is also proposed, which includes the following steps:

Step 1. Set the target reflectivity change rate Pre of film evaporation;

Step 2. Calibrate the multi-point reflectivity test equipment through the standard reflectivity sample;

Step 3. Use the substrate to replace the standard reflectance sample, and prepare the evaporation source to start evaporation;

Step 4. Start coating after the internal conditions of the evaporation chamber meet the coating requirements, and record the reflectance of each monitoring point at a set time interval during the coating process, and then compare the current reflectivity change rate of each monitoring point, and The comparison with the target reflectivity Pre is used to drive the movement of the evaporation source moving device to control the movement of the evaporation source in the two-dimensional plane, and make up for the thin film layer, and finally prepare a uniform film layer.

Compared with the traditional method of thickness monitoring for coating, the device and method for preparing large-size, uniform and thin films by using multi-point reflectivity monitoring of the present invention more directly monitor the reflectivity changes at various positions of large-size products during the coating process. It can solve the problem that single-point measurement cannot evaluate the uniformity of large-size products in the manufacturing process, improve product consistency, improve production yield, reduce production and processing links, and improve production efficiency.

Description of 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 the same reference numeral. For clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of a device for preparing a large-scale, uniform and thin device using multi-point reflectivity monitoring according to a preferred embodiment of the present invention.

2A-2C are schematic diagrams of an evaporation source moving device and its working principle according to a preferred embodiment of the present invention.

FIG. 3 is a schematic diagram of the distribution of detection points of a multi-point reflectance monitoring system according to a preferred embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating the change in reflectance of a specific product when a film layer is vapor-deposited according to a preferred embodiment of the present invention.

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

FIG. 6 is a schematic diagram of the reflectivity change rate of each monitoring position during the coating process according to a preferred embodiment of the present invention.

FIG. 7 is a schematic diagram of the reflectivity change rate of each monitoring position after the coating is completed according to a preferred embodiment of the present invention.

Detailed ways

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

Aspects of the invention are described in this disclosure 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 understood that the various concepts and embodiments described above, as well as those described in greater detail below, can be implemented in any of a number of ways, as the concepts and embodiments disclosed herein do not limited to any implementation. Additionally, some aspects of the present disclosure may be used alone or in any suitable combination with other aspects of the present disclosure.

1-7, according to a preferred embodiment of the present invention, a device for preparing large-size uniform thin films by using multi-point reflectivity monitoring is suitable for preparing large-size substrates by using multi-point reflectivity monitoring method. Large size uniform film. During the evaporation process, through the real-time monitoring of the reflectance of multiple monitoring sites, the real-time change rate of the reflectance is determined, and the evaporation source is controlled by the comparison of each site to supplement the weak positions. The preset value is set to complete the uniform evaporation of the entire film layer.

Compared with the traditional method of thickness monitoring for coating, the device and method for preparing large-size, uniform and thin films by using multi-point reflectivity monitoring of the present invention more directly monitor the reflectivity changes at various positions of large-size products during the coating process. It can solve the problem that single-point measurement cannot evaluate the uniformity of large-size products in the manufacturing process, improve product consistency, improve production yield, reduce production and processing links, and improve production efficiency.

The device for preparing a large-size uniform thin film using multi-point reflectance monitoring in conjunction with the embodiment shown in Figures 1-3 is suitable for products to be coated that are transparent or semi-transparent materials, and are still in a transparent or semi-transparent state during the coating process, The device includes a multi-point reflectance test equipment 101 , multiple bidirectional optical fibers 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 .

The evaporation chamber 103 is set to provide the required vacuum and temperature environment for film evaporation. As shown in FIG. 1 , the evaporation chamber 103 generally has a hole for the multi-way bidirectional optical fiber 102 to pass through and fix, and take corresponding measures to seal the hole.

The substrate 104 is supported at the middle position of the evaporation chamber 103 by the substrate support 104A, and the multi-way bidirectional optical fiber 102 and the evaporation source 105 are located above and below the substrate 104, respectively.

The middle of the evaporation chamber is isolated by a large-sized substrate 104 and a substrate support 104A to ensure that the film layer will not be deposited on the multi-way bidirectional optical fiber during the coating process.

The multi-point reflectance test equipment 101 is arranged outside the evaporation chamber, and is used to transmit monochromatic light signals through the multi-channel bidirectional optical fibers 102, and receive the corresponding multi-channel reflected light signals, thereby calculating the reflections of different positions of the measured object. For example, the photoelectric test module converts it into an electrical signal, and calculates the reflectivity of the measured object at different positions (ie, obtains the reflectivity monitoring value). It can also be intuitively represented or transmitted.

Preferably, the multi-point reflectance testing device 101 can simultaneously perform testing and calculation on the reflectance of more than two monitoring points. The multi-point reflectivity test device 101 can perform reflectivity tests of different monitoring points by time-division multiplexing of the light source and the photoelectric test module. Therefore, the number of monitoring points realized by the multi-point reflectivity test device 101 is not affected by its light source. , The number of photoelectric test modules is limited, but it will be limited by the number of multi-way bidirectional fibers 102. In some embodiments, the number of monitoring points that can be achieved can reach tens or even hundreds.

The multi-channel bidirectional optical fiber 102 can use the existing bidirectional conductive optical fiber to realize the function of exporting the optical signal generated by the multi-point reflectivity test equipment and returning the reflected optical signal at the same time.

The substrate 104 is used as a product to be coated, and at the same time, during the coating process, the reflectivity of the substrate changes with the thickness of the coating layer.

The evaporation source 105 is constituted as the raw material of the evaporation coating, and the film layer made by the evaporation source has the characteristic of being transparent or translucent. The evaporation source 105 is fixed on the evaporation source moving device 106 and moves synchronously with it.

As shown in FIG. 1 , the evaporation source 105 and the multi-way bidirectional optical fiber 102 are generally separated by a large-sized substrate 104 and its supporting frame, so as to prevent the evaporation source 105 from being evaporated on the multi-way bidirectional optical fiber 102, thereby affecting the multi-point reflectivity test Test results for device 101.

The evaporation source moving device 106 can realize any movement of the evaporation source in the evaporation chamber. As shown in FIGS. 2A-2C , the evaporation source moving device 106 realizes any movement of the evaporation source in the evaporation chamber through the evaporation source fixing frame 106A, the threaded rod 106B, the motor 106C, and the rotating shaft 106D. The rotating shaft 106D can be raised and lowered (when driven) to realize the movement in the z-axis direction in space. The evaporation source fixing frame 106A and the threaded rod 106B are integrally fixed by welding or the like. When the motor 106C rotates, it can drive the threaded rod 106B to perform linear movement, thereby realizing the movement of the evaporation source 105 in the r direction. The rotating shaft 106D can rotate in the horizontal direction. When the rotating shaft 106D rotates, the evaporation source 105 is driven to perform a rotating motion in the plane to realize the movement in the θ direction. The combination of the above motions can realize any movement of the evaporation source 105 in the z, r, and θ directions, thereby realizing any movement of the evaporation source 105 in the evaporation chamber. The motor 106C is particularly preferably a stepper motor.

That is to say, when the motor 106C works, it can drive the threaded rod 106B to move linearly, thereby realizing the linear movement of the evaporation source 105 . The rotating shaft 106D can rotate in a horizontal direction. When the rotating shaft 106D works, the evaporation source 105 is driven to perform a rotating motion in a plane. Combined with the operation of the motor 106C on the vertical axis and the rotating shaft 106D, any movement of the evaporation source 105 in the two-dimensional plane in the coating equipment can be realized.

In some embodiments, as shown in FIGS. 3 to 7 , for a large-sized circular substrate 104 , 13 reflectivity monitoring points can be set during the coating process, and bidirectional optical fibers are correspondingly set, among which 9 monitoring points can be set. The sites were distributed in a 3*3 rectangle centered on the base circle, and four were located at the outer center of each rectangle side.

In some preferred embodiments, the monitoring sites provided on the substrate 104 form an axisymmetric distribution, which is more conducive to regular monitoring and uniform evaporation replenishment.

The control system 110, connected with the point reflectance test device 101 and the evaporation source moving device 106, is configured to determine the current reflectance change rate Pn based on the monitored initial and minimum values of the multiple point reflectances, and based on each The comparison of the current reflectivity change rate Pn at each point and the comparison with the target reflectivity Pre can drive the movement of the evaporation source moving device to control the evaporation source to move in a two-dimensional plane, and make up for the thin film layer. The final preparation A uniform film layer is produced.

In some embodiments, as shown in FIG. 4 , there are not only the initial reflectivity value R1 and the reflectivity monitoring value R during the reflectivity monitoring process, but also the lowest point R2 in the reflectivity curve, so the reflectivity change rate P The calculation method of , requires the multi-point reflectance test equipment 101 to adopt a corresponding method for calculation. The technical method is shown in Fig. 5. First, the initial reflectivity R1 is recorded and recorded, and R1 is stored as the minimum reflectivity value R2. Then start to record the reflectivity monitoring value R in real time, and judge the size of R and R2. When R is less than R2, cover R2 with the value of R, and then according to the formula reflectivity change rate Pn=(R+R1-2R2)/R1 The current reflectance change rate Pn is obtained and output. After that, each time the current reflectance R value is recorded, the size of R and R2 is judged once, the R2 value is re-stored, and the current reflectance change rate Pn is finally output.

With reference to the implementation process shown in FIG. 5 , the control system 110 includes a reflectance calculation unit and an evaporation source motion control unit, wherein the reflectance calculation unit is configured to calculate the current reflectance change rate in the following manner:

First record the initial reflectivity R1, and store the initial reflectivity R1 as the lowest reflectivity value R2;

Then record the reflectance monitoring value R in real time, and judge the size of R and R2. When R is less than R2, use the value of R to replace R2, that is, execute R2=R, otherwise it is not covered, that is, keep R2 unchanged;

Then according to the calculation formula of the reflectivity change rate Pn, the current reflectivity change rate Pn is obtained and output;

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, and drives the movement of the evaporation source moving device according to the comparison result to control the evaporation source in two dimensions. In-plane movement, the thin film layer is supplemented, and compared with the target reflectivity Pre, a uniform film layer is finally prepared, where Pn=(R+R1-2R2)/R1.

In some embodiments, as shown in FIG. 6 , the reflectivity change rate Pn of each monitoring point during the coating process is not the same. Therefore, the reflectivity change rate Pn of each position needs to be compared during the coating process to determine the reflectivity change rate of each position. The thickness of the film layer is determined, and the position of the evaporation source 105 is moved according to the result to make up for the thinner film layer, and finally a film layer with better uniformity is prepared, as shown in FIG. 7 .

1, 2A-2C, and FIG. 5, according to the disclosure of the present invention, a method for preparing a large-size uniform thin film using multi-point reflectance monitoring is also proposed, which includes the following steps:

Step 1. Set the target reflectivity change rate Pre of film evaporation;

Step 2. Calibrate the multi-point reflectivity test equipment through the standard reflectivity sample;

Step 3. Use the substrate to replace the standard reflectance sample, and prepare the evaporation source to start evaporation;

Step 4. Start coating after the internal conditions of the evaporation chamber meet the coating requirements, and record the reflectance of each monitoring point at a set time interval during the coating process, and then compare the current reflectivity change rate of each monitoring point, and The comparison with the target reflectivity Pre is used to drive the movement of the evaporation source moving device to control the movement of the evaporation source in the two-dimensional plane, and make up for the thin film layer, and finally prepare a uniform film layer.

In step 1, the reflectivity change rate of the coating target can be calculated by theoretical calculation based on conditions such as the large-sized substrate 104, the evaporation source 105, and the thickness of the film layer, through model calculation. For example, the calculation method proposed by Li Xiaofeng et al. of Nanjing University of Science and Technology.

Before the reflectance monitoring of the present invention is implemented, and before coating starts, standard reflectance samples need to be installed at each monitoring position where the large-size substrate 104 is installed to calibrate the multi-point reflectance testing equipment 101 . Then, after the calibration of the multi-point reflectivity test equipment 101 is completed, take out the standard reflectivity sample, place the large-sized substrate 104 and the evaporation source 105, and check whether the evaporation source 105 and the multi-way bidirectional optical fiber 102 are isolated after the placement is completed. Carry out the coating process.

Coating starts after the internal conditions of the evaporation chamber 103 meet the coating requirements. In some embodiments, during the coating process, the value of the reflectivity change rate Pn of each point is compared at regular intervals, and the position of the evaporation source is moved according to the comparison result, and the position with the lowest reflectivity change rate Pn is supplemented with coating until each point is All reach the target reflectance change rate of the coating.

From the above technical solutions, the device and method for preparing large-size uniform thin films by using multi-point reflectance monitoring proposed by the present invention have the following significant beneficial effects:

1) The present invention adopts the multi-point reflectance monitoring method to prepare large-size films, which can conveniently perform multi-point in-situ measurement of product performance without blocking the product, and monitor the film layer changes at different positions of the product in real time;

2) The present invention adopts the multi-point reflectance monitoring method to prepare large-size thin films, which can directly understand the optical performance parameters of the product and the uniformity of the film layer during the preparation process. Whether the product meets the design requirements;

3) The present invention can correct the uniformity of the film layer by moving the position of the evaporation source during the coating process according to the monitoring results of different positions of the large-size substrate;

4) The aforementioned technology of the present invention, as a whole solution, is suitable for the manufacture of various large-size optical products, the monitoring data of the production process is perfect, and the uniformity of the product film layer is good, which can improve the production efficiency and yield of optical products.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention.

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

Claims (8)

1. a device utilizing multi-point reflectivity monitoring to prepare a large-size uniform thin film, suitable for the product to be coated is a transparent or translucent material, and is still in a transparent or translucent state in the coating process simultaneously, it is characterized in that, the device comprises: Evaporation chamber, multi-point reflectance test equipment, multi-way bidirectional optical fiber, substrate, evaporation source, evaporation source moving device and control system, wherein: The evaporation chamber is set to provide the required vacuum and temperature environment for film evaporation, and the substrate is supported in the middle position of the evaporation chamber by the substrate support; The multi-point reflectivity test equipment set outside the evaporation chamber is used to transmit monochromatic light signals through the multi-channel bidirectional optical fibers and receive the corresponding multi-channel reflected light signals, thereby calculating the reflections of different positions of the measured object. Rate; The evaporation source is constituted as a raw material for evaporation coating, and the film layer made 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 it; The control system is configured to determine the current reflectivity change rate Pn based on the monitored initial and minimum values of reflectivity at multiple points, and based on the comparison of the current reflectivity change rate Pn at each point, and the target reflectance The comparison of the rate Pre is used to drive the movement of the evaporation source moving device to control the movement of the evaporation source in the two-dimensional plane, to complement the thin film layer, and finally to prepare a uniform film layer. 2. The device according to claim 1, wherein the evaporation chamber is provided with a hole for the multi-way bidirectional optical fiber to pass through and fix, and the hole is sealed . 3 . The device for preparing large-size uniform thin films using multi-point reflectivity monitoring according to claim 1 , wherein at least 10 paths of the multi-path bidirectional optical fibers are provided. 4 . 4. The device according to claim 1, wherein the substrate is a circular substrate, and 13 monitoring sites are provided in the process of vapor deposition of the film, respectively. Correspondingly, bidirectional optical fibers are arranged, among which 9 monitoring sites are distributed in a 3*3 rectangle centered on the base circle, and 4 are located at the outer center of each rectangular side. 5 . The device for preparing large-sized uniform thin films by using multi-point reflectance monitoring according to claim 4 , wherein the monitoring points form an axisymmetric distribution. 6 . 6 . The device for preparing large-size uniform thin films using multi-point reflectivity monitoring according to claim 1 , wherein the multi-way bidirectional optical fiber and the evaporation source are respectively located above and below the substrate. 7 . 7. The device for preparing large-sized uniform thin films by using multi-point reflectivity monitoring according to any one of claims 1-6, wherein the control system comprises a reflectivity calculation unit and an evaporation source motion control unit, wherein The reflectance calculation unit is configured to calculate the current reflectance change rate as follows: First record the initial reflectivity R1, and store the initial reflectivity R1 as the lowest reflectivity value R2; Then record the reflectance monitoring value R in real time, and judge the size of R and R2. When R is less than R2, use the value of R to replace R2, that is, execute R2=R, otherwise it is not covered, that is, keep R2 unchanged; Then according to the calculation formula of the reflectivity change rate Pn, the current reflectivity change rate Pn is obtained and output; 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, and drives the movement of the evaporation source moving device according to the comparison result to control the evaporation source in two dimensions. In-plane movement, the thin film layer is supplemented, and compared with the target reflectivity Pre, a uniform film layer is finally prepared, where Pn=(R+R1-2R2)/R1. 8. A method for preparing a large-size uniform thin film based on the device according to any one of claims 1-7, characterized in that, comprising the following steps: Step 1. Set the target reflectivity change rate Pre of film evaporation; Step 2. Calibrate the multi-point reflectivity test equipment through the standard reflectivity sample; Step 3. Use the substrate to replace the standard reflectance sample, and prepare the evaporation source to start evaporation; Step 4. Start coating after the internal conditions of the evaporation chamber meet the coating requirements, and record the reflectance of each monitoring point at a set time interval during the coating process, and then compare the current reflectivity change rate of each monitoring point, and The comparison with the target reflectivity Pre is used to drive the movement of the evaporation source moving device to control the movement of the evaporation source in the two-dimensional plane, and make up for the thin film layer, and finally prepare a uniform film layer.

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