Evaporation cavity structure with multi-stage temperature control function

Abstract

The evaporation cavity structure with multi-stage temperature control function comprises a vacuum chamber, a vacuum pump communicated with the vacuum chamber, a substrate holder arranged in the vacuum chamber for placing a substrate, a heating system, a temperature measuring system and a PLC controller. The heating system comprises three independent heating devices arranged along the axial direction of the vacuum chamber. The three independent heating devices divide the vacuum chamber into three independent heating zones along the axial direction. The temperature measuring system comprises three temperature measuring devices arranged one-to-one corresponding to the three independent heating zones. The PLC controller is in communication connection with the heating devices and the temperature measuring devices, configured to receive feedback signals of the temperature measuring devices and independently adjust the heating power of the corresponding heating zones. The evaporation cavity structure divides the cavity into multiple independent heating zones, and configures independent temperature monitoring and PLC feedback control for each zone, thereby improving the temperature uniformity inside the cavity, improving the product yield and performance, avoiding energy waste through independent control of each zone, and reducing the production cost.

Description

Technical Field

[0001] This utility model relates to the field of vacuum coating technology, specifically to an evaporation chamber structure with multi-level temperature control function. Background Technology

[0002] Evaporation coating is a process that uses heat to evaporate or sublimate a film material in a vacuum environment, which then condenses onto a substrate surface to form a thin film. It is widely used in industries such as optics, semiconductors, microelectronics, and decoration. In this process, the temperature environment within the vacuum chamber is a key factor determining the film quality (such as thickness uniformity, adhesion, internal stress, and crystal morphology). Firstly, the substrate itself needs to be heated to a suitable and stable temperature. The substrate temperature directly affects the migration rate and nucleation density of film materials on the substrate surface, thus affecting the film's density and bonding strength. Secondly, the entire chamber wall also needs to be maintained at a certain temperature to prevent gaseous film materials from condensing on the cooler chamber walls before reaching the substrate. If film materials condense on the chamber walls, it not only wastes the film material but also contaminates the chamber, affecting film purity and subsequent processes.

[0003] However, traditional evaporation coating equipment generally uses a single heater to heat the entire vacuum chamber. Due to the large size of the chamber, the radiation, conduction, and convection of heat in the vacuum are complex. A single heat source inevitably leads to an uneven temperature field within the chamber. In particular, along the axial direction of the substrate holder, there is a gradient distribution with high temperature in the middle and low temperature at both ends. This uneven temperature field directly causes differences in thickness, stress, and microstructure of the films deposited at different locations on the substrate, seriously affecting the consistency of product performance and yield.

[0004] Therefore, researching novel evaporator cavity structures with multi-level temperature control functions and solving the above problems is of great significance for improving the temperature field uniformity of evaporator cavity structures. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides an evaporation chamber structure with multi-level temperature control. This structure divides the chamber into multiple independent heating zones, each equipped with independent temperature monitoring and PLC feedback control. This allows for rapid response and precise maintenance of the set temperature in each zone, improving temperature uniformity within the chamber. The PLC controller allows for flexible creation and maintenance of various desired temperature distribution patterns within the chamber to meet the needs of advanced coating processes with different film materials and performance requirements. The uniform and controllable temperature field ensures that the condensation rate of film vapor at various points on the substrate is consistent with the growth environment, thereby significantly improving the uniformity of film thickness, stress, and microstructure, directly enhancing product yield and performance. Independent zone control avoids energy waste caused by "overall overheating for localized purposes," reducing production costs.

[0006] The technical solution of this utility model is as follows: An evaporation chamber structure with multi-stage temperature control includes a vacuum chamber, a vacuum pump connected to the vacuum chamber, and a substrate holder placed inside the vacuum chamber for placing substrates. It also includes a heating system, a temperature measuring system, and a PLC controller. The heating system includes three independent heating devices arranged along the axial direction of the vacuum chamber, which divide the vacuum chamber into three independent heating zones. The temperature measuring system includes three temperature measuring devices that correspond one-to-one with the three independent heating zones. The PLC controller is communicatively connected to the heating devices and the temperature measuring devices and is configured to receive feedback signals from each temperature measuring device and independently adjust the heating power of the corresponding heating zone.

[0007] The heating device is an electromagnetic heating coil.

[0008] The electromagnetic induction frequency of the electromagnetic heating coil is 2KHz-30KHz.

[0009] The temperature measuring device is a temperature sensor installed on the wall of the vacuum chamber.

[0010] The temperature sensor is a PT100 platinum resistance temperature sensor.

[0011] The evaporation chamber structure with multi-level temperature control also includes a membrane evaporation device, which includes an evaporation dish, an evaporation heat source, a cover, and a membrane. The evaporation dish is located at the bottom of the substrate holder, the evaporation heat source is located on the outer wall of the evaporation dish, the cover has several evaporation holes, the cover is fastened to the top of the evaporation dish, and the membrane is placed in the evaporation dish.

[0012] The heat source for evaporation is an electromagnetic heating coil.

[0013] The three independent heating zones are a front heating zone, a middle heating zone, and a rear heating zone. The PLC controller is configured to independently control the heating power of the front heating zone and the rear heating zone to be higher or lower than the heating power of the middle heating zone, so as to form the required axial temperature gradient in the vacuum chamber.

[0014] The heating device is installed on the inner wall of the vacuum chamber and includes a front heating device, an intermediate heating device, and a rear heating device respectively located at the front, middle, and rear of the vacuum chamber.

[0015] The substrate holder includes a support frame and a tray. The support frame includes two parallel guide rods and columns and crossbars for fixing the guide rods. The tray includes an L-shaped left bracket and a right bracket that are symmetrically arranged and slidably fitted onto the guide rods. The substrate is placed on the base plate of the L-shaped left bracket and the right bracket.

[0016] The beneficial effects of this utility model are as follows: 1. The evaporation chamber structure with multi-level temperature control disclosed in this utility model can improve the uniformity of the temperature field. Traditional evaporation coating equipment uses a single heater to heat the entire vacuum chamber. The chamber space is large, and the heat radiation, conduction and convection distribution in the vacuum is complex, resulting in high temperature in the middle and low temperature at both ends along the axial direction of the substrate holder, which leads to an uneven temperature field and affects the film thickness, stress and microstructure consistency. In contrast, this structure is equipped with three independent heating devices arranged along the axial direction of the vacuum chamber, dividing the vacuum chamber into three independent heating zones. The PLC controller receives feedback signals from each temperature measuring device and independently adjusts the heating power of the corresponding heating zone, which can effectively improve the axial temperature gradient, improve the uniformity of the temperature field, and thus improve the consistency of product performance and yield.

[0017] 2. The evaporation chamber structure with multi-level temperature control function disclosed in this utility model can realize flexible temperature control. The PLC controller can independently control the heating power of the front heating zone and the rear heating zone to be higher or lower than the heating power of the middle heating zone. It can form the required axial temperature gradient in the vacuum chamber, meet the diverse requirements of different processes for temperature distribution, and enhance the adaptability of the equipment to different thin film preparation processes.

[0018] 3. The evaporation chamber structure with multi-level temperature control disclosed in this utility model can ensure a suitable temperature for the substrate. The substrate temperature directly affects the migration rate and nucleation density of film atoms on the substrate surface, thereby affecting the film density and bonding strength. The multi-level temperature control structure can more accurately control the temperature of the area where the substrate is located, so that the substrate is heated to a suitable and stable temperature, which is beneficial to improving the film quality.

[0019] 4. The evaporation chamber structure with multi-level temperature control function disclosed in this utility model facilitates substrate placement and operation. The substrate holder includes a support frame and a tray. The support frame has parallel guide rods and a fixing structure. The tray can be slidably mounted on the guide rods to facilitate substrate placement, operation and adjustment of substrate position, and help improve production efficiency and operational convenience. Attached Figure Description

[0020] The advantages and solutions of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this invention.

[0021] In the attached diagram: Figure 1 This is an embodiment of the evaporation chamber structure with multi-level temperature control. Figure 2 for Figure 1 Sectional view of AA; Figure 3 This is a schematic diagram of the structure of the membrane evaporation device with a multi-level temperature control evaporation chamber structure according to an embodiment of the present invention; Figure 4 This is a front view of the substrate holder of the evaporation chamber structure with multi-level temperature control function according to an embodiment of the present invention; Figure 5 This is a top view of the substrate holder of the evaporation chamber structure with multi-level temperature control according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the left bracket and guide rod of the evaporator chamber structure with multi-level temperature control function according to an embodiment of the present invention.

[0022] The components represented by the various reference numerals in the diagram are: This utility model includes: 100, vacuum chamber; 110, temperature measuring hole; 200, vacuum pump; 300, heating device; 310, front heating device; 320, intermediate heating device; 330, rear heating device; 400, temperature measuring device; 410, temperature sensor; 500, PLC controller; 600, substrate holder; 610, support frame; 611, column; 612, guide rod; 613, crossbar; 620, tray; 621, left bracket; 622, right bracket; 700, substrate; 800, membrane evaporation device; 810, evaporation dish; 820, evaporation heat source; 830, cover; 831, evaporation hole; 840, membrane material. Detailed Implementation

[0023] like Figures 1 to 3As shown, the evaporation chamber structure with multi-stage temperature control mainly includes a vacuum chamber 100, a vacuum pump 200, a heating device 300, a temperature measuring device 400, a PLC controller 500, a substrate holder 600, and a film evaporation device 800. The vacuum pump 200 is connected to the vacuum chamber 100 through a pipe and is used to evacuate the chamber to the high vacuum environment required by the process. The substrate holder 600 is located inside the vacuum chamber 100 and is used to support the substrate 700 to be coated. The film evaporation device 800 is located at the bottom of the vacuum chamber 100 and directly below the substrate holder 600.

[0024] The core innovation of this utility model lies in the multi-level temperature control system composed of the heating device 300, the temperature measuring device 400, and the PLC controller 500.

[0025] like Figure 1 and Figure 2 As shown, the heating device 300 is fixedly installed on the inner wall of the vacuum chamber 100. The heating device 300 is divided into three independent heating zones along the axial direction of the vacuum chamber 100: a front heating device 310, a middle heating device 320, and a rear heating device 330. These three heating zones spatially correspond to the front, middle, and rear regions of the substrate 700, respectively. Preferably, the heating device 300 uses an electromagnetic heating coil, and its operating frequency is preferably between 2KHz and 30KHz. Electromagnetic heating in this frequency range has the advantages of high thermal efficiency, uniform heating, low thermal inertia, and easy precise control. The temperature measuring device 400 is set one-to-one with the heating zones. Temperature measuring holes 110 are respectively processed on the front, middle, and rear walls of the vacuum chamber 100. A temperature sensor 410 is precisely installed in each temperature measuring hole 110 for real-time detection of the temperature of the corresponding area. The temperature sensor 410 is preferably a PT100 platinum resistance temperature sensor with high measurement accuracy and good long-term stability.

[0026] like Figure 1 and Figure 2As shown, the PLC controller 500 is located outside the vacuum chamber 100 and is electrically connected to all heating devices 300 and temperature sensors 410 via shielded cables. The PLC controller 500 stores a control program that receives measurement signals from the three temperature sensors 410 in real time and compares them with their respective preset target temperature values. Based on the deviation obtained from the comparison, the PLC controller 500 independently adjusts the power output to the front heating device 310, the intermediate heating device 320, and the rear heating device 330 (e.g., by adjusting the duty cycle or current) using a built-in PID control algorithm, thereby achieving independent closed-loop control of each heating zone and ensuring that the temperature of each zone quickly reaches and stabilizes at the set value. It should be noted that adjusting power or duty cycle or current using a PID control algorithm is common knowledge; this patent does not improve PID control but only proposes the division of three heating zones and different target temperature settings.

[0027] The PLC controller 500 can set different target temperatures for the three heating zones. For example, to actively compensate for the spatial difference in emission flux of the evaporation source, the temperatures of the front and rear heating zones can be set slightly higher than those of the middle heating zone, thereby forming a preset "concave"-shaped temperature field in the vacuum chamber. This controllable temperature gradient can guide the condensation rate of the film material atoms to tend towards uniformity, ultimately obtaining a film with extremely uniform thickness. The PLC controller 500 can receive and store the independent target temperature parameters of each heating zone and output independent control signals through its internal control loop, so that the heating power of the front and rear heating zones can be different from that of the middle heating zone, thereby forming the required temperature distribution in the cavity. Once the division of the three heating zones and the different target temperature settings are established, how the PLC controller controls the temperature is common sense.

[0028] Regarding other components Figures 1 to 3 A specific embodiment of the membrane evaporation apparatus 800 is shown, including an evaporation dish 810 holding a membrane 840, an evaporation heat source 820 wound around its exterior, and a cover 830 fastened to the top. Preferably, the evaporation heat source 820 is an electromagnetic heating coil. The cover 830 is machined with a plurality of evaporation holes 831, which are preferably evenly distributed in a concentric circle to help the evaporation airflow diffuse more evenly to the upper substrate area.

[0029] Figures 1 to 6 A specific embodiment of the substrate holder 600 is shown. Its support frame 610 consists of two parallel guide rods 612, a crossbar 613 connecting the two ends of the guide rods, and a column 611 fixed to the bottom of the guide rods. The tray 620 consists of symmetrically arranged L-shaped left bracket 621 and right bracket 622, which are slidably fitted on the two guide rods 612 to facilitate flexible adjustment of the position according to the size of the substrate 700 and to stably support the substrate 700.

[0030] The working process of the evaporation chamber structure with multi-stage temperature control is as follows: Loading: Mount the substrate 700 on the substrate holder 600, place the membrane material 840 into the evaporating dish 810, and close and lock the vacuum chamber 100.

[0031] Vacuuming: Start vacuum pump 200 to evacuate vacuum chamber 100 to the high vacuum level required by the process.

[0032] Preheating and temperature control: The target temperature of the three heating zones (front, middle and rear) is set by the PLC controller 500. The PLC controller 500 automatically starts each heating device 300 and performs precise PID adjustment based on the feedback from the temperature sensor 410 until each zone reaches and stabilizes at the set temperature. This process can be uniform heating or gradient heating.

[0033] Evaporation coating: The evaporation heat source 820 of the film evaporation device 800 is started to heat the film 840 to evaporate it. The evaporated film atoms or molecules form a uniform vapor cloud through the evaporation holes 831 on the cover 830 and are deposited upwards on the surface of the substrate 700, which has been preheated and is in a precisely temperature-controlled environment, to form a high-quality thin film.

[0034] Cooling and Removal: After the process is completed, the evaporation heat source 820 and the heating device 300 are turned off one after the other. After the cavity has cooled to a safe temperature, atmospheric air is filled into the vacuum chamber 100, the cavity is opened, and the coated substrate 700 is removed.

[0035] This evaporation chamber structure with multi-level temperature control divides the chamber into multiple independent heating zones, each equipped with independent temperature monitoring and PLC feedback control. This allows for rapid response and precise maintenance of the set temperature in each zone, improving temperature uniformity within the chamber. By programming the PLC controller, various desired temperature distribution patterns can be flexibly created and maintained within the chamber, such as uniform fields or specific temperature gradients, to meet the needs of advanced coating processes with different film materials and performance requirements. The uniform and controllable temperature field ensures that the condensation rate of film vapor at various points on the substrate is consistent with the growth environment, thereby significantly improving the uniformity of film thickness, stress, and microstructure, directly enhancing product yield and performance. Independent zone control avoids energy waste caused by "overall overheating for localized purposes," reducing production costs.

Claims

1. An evaporation chamber structure with multi-stage temperature control, comprising a vacuum chamber (100), a vacuum pump (200) connected to the vacuum chamber (100), and a substrate holder (600) disposed within the vacuum chamber (100) for placing a substrate (700), characterized in that: It also includes a heating system, a temperature measuring system and a PLC controller (500). The heating system includes three independent heating devices (300) arranged along the axial direction of the vacuum chamber (100). The three independent heating devices (300) divide the vacuum chamber (100) into three independent heating zones along the axial direction. The temperature measuring system includes three temperature measuring devices (400) that are set one-to-one with the three independent heating zones. The PLC controller (500) is communicatively connected to the heating devices (300) and the temperature measuring devices (400), and is configured to receive feedback signals from each temperature measuring device (400) and independently adjust the heating power of the corresponding heating zone.

2. The evaporation chamber structure with multi-level temperature control function according to claim 1, characterized in that, The heating device (300) is an electromagnetic heating coil.

3. The evaporation chamber structure with multi-level temperature control function according to claim 2, characterized in that, The electromagnetic induction frequency of the electromagnetic heating coil is 2KHz-30KHz.

4. The evaporation chamber structure with multi-level temperature control function according to claim 1, characterized in that, The temperature measuring device (400) is a temperature sensor (410) installed on the wall of the vacuum chamber (100).

5. The evaporation chamber structure with multi-level temperature control function according to claim 4, characterized in that, The temperature sensor (410) is a PT100 platinum resistance temperature sensor.

6. The evaporation chamber structure with multi-level temperature control function according to claim 1, characterized in that, It also includes a membrane evaporation device (800), which includes an evaporation dish (810), an evaporation heat source (820), a cover (830), and a membrane (840). The evaporation dish (810) is located at the lower part of the substrate holder (600), the evaporation heat source (820) is located on the outer wall of the evaporation dish (810), the cover (830) is provided with a number of evaporation holes (831), the cover (830) is fastened to the upper part of the evaporation dish (810), and the membrane (840) is placed in the evaporation dish (810).

7. The evaporation chamber structure with multi-level temperature control function according to claim 6, characterized in that, The evaporation heat source (820) is an electromagnetic heating coil.

8. The evaporation chamber structure with multi-level temperature control function according to claim 1, characterized in that, The three independent heating zones are a front heating zone, a middle heating zone, and a rear heating zone. The PLC controller (500) is configured to independently control the heating power of the front heating zone and the rear heating zone to be higher or lower than the heating power of the middle heating zone, so as to form the required axial temperature gradient in the vacuum chamber (100).

9. The evaporation chamber structure with multi-level temperature control function according to claim 1, characterized in that, The heating device (300) is installed on the inner wall of the vacuum chamber (100) and includes a front heating device (310), an intermediate heating device (320) and a rear heating device (330) respectively disposed at the front, middle and rear of the vacuum chamber (100).

10. The evaporation chamber structure with multi-level temperature control function according to claim 1, characterized in that, The substrate holder (600) includes a support frame (610) and a tray (620). The support frame (610) includes two parallel guide rods (612) and a column (611) and a crossbar (613) for fixing the guide rods (612). The tray (620) includes an L-shaped left bracket (621) and a right bracket (622) that are symmetrically arranged and slidably fitted on the guide rods (612). The substrate (700) is placed on the base plate of the L-shaped left bracket (621) and the right bracket (622).

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