Heating device and method for vacuum coating apparatus, and coating apparatus

Abstract

Disclosed in the present application are a heating device and method for a vacuum coating apparatus, and a coating apparatus, belonging to the field of vacuum coating. The heating device for a vacuum coating apparatus comprises a heating plate, the heating plate comprising a peripheral area and a central area. The peripheral area and the central area have different thermal emissivity values, so as to heat corresponding areas of a coating substrate to enable temperature differences of all portions of the coating substrate to be within a preset range. After being subjected to surface treatment, the peripheral area and the central area obtain different thermal emissivity values, surface treatment modes being at least one of oxidation, wet treatment, coating coverage, film coating, sand blasting roughening, wire drawing, melt-blowing and polishing. The present application can perform differentiated heating on different positions of large-size coating substrates, so as to effectively reduce the temperature differences between silicon wafers on the same substrate, thus improving coating uniformity.

Description

Heating device and method for vacuum coating equipment and coating equipment Technical Field

[0001] The present application belongs to the field of vacuum coating technology and relates to a coating heating device, and specifically to a heating device, method and coating equipment for vacuum coating equipment. Background Art

[0002] During the vacuum coating process of silicon wafers, the silicon wafers need to be heated so that they are within a preset temperature range to achieve smooth and effective implementation of vacuum coating.

[0003] Poor coating thickness uniformity in large-scale vacuum coating equipment is a current technical issue, and effectively addressing this issue has become a challenging problem within the field. This is due to a number of factors: some coating processes are significantly affected by the standing wave effect of the RF power source, resulting in varying thicknesses around and in the center of the coating area; and some high-precision coating processes require minimal temperature variation across the entire coating area to achieve the required uniform coating.

[0004] To solve this problem, the temperature of the coated substrate can be adjusted so that the process conditions at the periphery, the center, and even all parts of the coated substrate are different, thereby compensating for the original thickness differences and achieving uniform coating. However, the thermal emissivity of the existing heating plate is consistent. When heating the vacuum coating, this heating device radiates roughly the same amount of heat to each position of the silicon wafer. However, the heat dissipation rate of the silicon wafers at the periphery of large-sized coated substrates is faster than that of the silicon wafers in the center area. When the radiated heat is basically the same, this difference in heat dissipation rate will lead to large differences in the temperature of the silicon wafers on the same substrate, which will not solve the above-mentioned uneven coating problem. Summary of the Invention

[0005] The present application aims to solve at least one of the technical problems in the above-mentioned related technologies to a certain extent.

[0006] To this end, the purpose of this application is to provide a heating device, method and coating equipment for vacuum coating equipment, which can differentially heat different positions of a large-size coated substrate, effectively reduce the temperature difference between silicon wafers on the same substrate, improve the coating uniformity, and solve the problem of poor coating thickness uniformity of large-size vacuum coating equipment.

[0007] In order to solve the above technical problems, this application is implemented as follows:

[0008] An embodiment of the present application provides a heating device for a vacuum coating device, comprising a heating plate, wherein the heating plate comprises a surrounding area and a middle area;

[0009] The surrounding areas and the middle area have different thermal radiation rates, so as to heat the corresponding areas of the coating substrate so that the temperature difference of each part of the coating substrate is within a preset range.

[0010] In addition, the heating device of the vacuum coating equipment according to the present application may also have the following additional technical features:

[0011] In some embodiments, the surrounding area and the middle area obtain different thermal emissivity after surface treatment; the surface treatment method is at least one of oxidation, wet treatment, coating, plating, sandblasting, brushing, melt spraying and polishing.

[0012] In some embodiments, the surface treatment method is at least one of oxidation, coating and plating, and after treatment, a thermal emissivity regulating film layer is formed on the surface of the heating plate; the thickness of the film layer is 1 μm~500 μm.

[0013] In some embodiments, the surface treatment method is melt-blowing, and after treatment, a thermal emissivity regulating film layer is formed on the surface of the heating plate; the thickness of the film layer is 0.5 mm to 10 mm.

[0014] In some embodiments, the peripheral area and the middle area are treated with the same or different surface treatments;

[0015] The surface treatment coverage of the peripheral area is different from the surface treatment coverage of the middle area.

[0016] In some embodiments, the surface treatment coverage of the surrounding area is 100%.

[0017] In some embodiments, the thermal emissivity of the surrounding area decreases from the edge to the center, and the thermal emissivity of the surrounding area is greater than the thermal emissivity of the middle area;

[0018] Alternatively, the thermal emissivity of the surrounding areas increases from the edge to the center, and the thermal emissivity of the surrounding areas is less than the thermal emissivity of the middle area.

[0019] In some embodiments, the surface treatment methods adopted for the surrounding area and the middle area are both roughening treatment, so that the surfaces of the surrounding area and the middle area are set with different roughness.

[0020] An embodiment of the present application also provides a vacuum coating device, which includes the heating device of the vacuum coating device as described above.

[0021] The present application also provides a heating method for vacuum coating equipment, which uses the heating device of the vacuum coating equipment as described in any of the above items to heat the coating substrate in the vacuum chamber, wherein the heating device includes a heating plate, and the heating plate includes a surrounding area and a middle area;

[0022] The temperature of the surrounding areas and the middle area of ​​the coating substrate is regulated by controlling the thermal radiation rates of the surrounding areas and the middle area.

[0023] In addition, the heating method of the vacuum coating equipment according to the present application may also have the following additional technical features:

[0024] In some embodiments, the thermal emissivity of the surrounding areas and the middle area is controlled by treating the heating plate with at least one surface treatment method selected from oxidation, coating, plating, sandblasting and polishing, so that the surrounding areas and the middle area of ​​the heating plate have different thermal emissivity.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] In the embodiment of the present application, the heating device of the provided vacuum coating equipment is equipped with a thermal radiation regulating layer such as an oxide layer to fully cover the areas around the hot plate corresponding to the lower temperature of the silicon wafer, and an oxide layer to partially cover the middle area corresponding to the higher temperature of the silicon wafer. The principle of different thermal radiation between the oxidized surface and the non-oxidized surface is utilized to reduce the temperature difference between the silicon wafers, which can effectively solve the problem of uneven coating caused by the large temperature difference of the silicon wafers at different positions in the prior art.

[0027] The vacuum coating apparatus of the present application includes the heating device of the vacuum coating apparatus described above, and thus has at least all the features and advantages of the heating device described above, which will not be described in detail here. Additional aspects and advantages of the present application will be described in part in the following description, and in part will become apparent from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic structural diagram of a heating device of a vacuum coating device disclosed in one embodiment of the present application (the oxidation area is a rectangle);

[0029] FIG2 is a schematic structural diagram of a heating device of a vacuum coating device disclosed in another embodiment of the present application (the oxidation area is a chamfered rectangle);

[0030] FIG3 is a schematic structural diagram of a heating device of a vacuum coating device disclosed in yet another embodiment of the present application (the oxidation area is a circle);

[0031] FIG4 is a schematic structural diagram of a heating device of a vacuum coating device disclosed in yet another embodiment of the present application (the oxidation unit is circular);

[0032] FIG5 is a schematic structural diagram of a heating device of a vacuum coating device disclosed in yet another embodiment of the present application (the oxidation unit is in the shape of a long strip);

[0033] FIG6 is a schematic structural diagram of a heating device of a vacuum coating device disclosed in yet another embodiment of the present application (with different patterned layer coverage);

[0034] FIG7 is a schematic structural diagram of a heating device of a vacuum coating device disclosed in yet another embodiment of the present application (the shapes of the patterned layers in different areas are different).

[0035] Description of reference numerals:

[0036] 1-Fully oxidized region; 2-Partially oxidized region; 3-Oxidation unit. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0038] The embodiments of the present application are described in detail below through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0039] In some embodiments of the present application, a heating device for vacuum coating equipment is provided, which can be applied to equipment for preparing photovoltaic modules or solar cells. For example, in the preparation process of solar cells, the process of vacuum coating the cell wafers is involved. The heating device can be used to achieve heating treatment before and during vacuum coating of the cell wafers. It can be used to solve the problem of temperature difference between silicon wafers at different positions during vacuum coating caused by the uniform thermal emissivity of the heating plate and the different heat dissipation rates of silicon wafers at different positions on the same substrate in the prior art, thereby greatly improving the uniformity of vacuum coating and the yield rate of the cell wafers. In addition, the heating device can also be used in other equipment or for other types of heating treatment. The embodiments of the present application do not impose specific restrictions on the specific use scenarios and working conditions of the heating device.

[0040] Specifically, the heating device of the vacuum coating equipment includes: a heating plate and an energy supply unit (not shown in the figure). The energy supply unit is connected to the heating plate and is used to provide energy to the heating plate for heating. The heating plate includes a first area located on the four sides and a second area located in the middle. The surface of the first area is provided with a first patterned layer, and the surface of the second area is provided with a second patterned layer. The first patterned layer and the second patterned layer are used to regulate the thermal emissivity of the heating plate. It should be noted that the thermal emissivity of the first area refers to the overall thermal emissivity of the first area of ​​the heating plate, and the thermal emissivity of the second area refers to the overall thermal emissivity of the second area of ​​the heating plate.

[0041] In some embodiments of the present application, please refer to FIG1 , the heating device includes: a heating plate and an energy supply unit (not shown in the figure), the energy supply unit is connected to the heating plate, and is used to provide energy to the heating plate for heating. The heating plate includes a fully oxidized area 1 located on the four sides and a partially oxidized area 2 located in the middle, and the partially oxidized area 2 includes a number of oxidation units 3 arranged therein and a non-oxidized area located between each oxidation unit 3. The present application fully oxidizes the areas on the four sides of the heating plate corresponding to the lower temperature of the silicon wafer, and partially oxidizes the areas in the middle corresponding to the higher temperature of the silicon wafer, and utilizes the different principles of thermal radiation of the oxidized surface and the non-oxidized surface to regulate the temperature of the silicon wafers in the four sides and the middle area.

[0042] The fully oxidized area 1 and the partially oxidized area 2 are both located on the front of the heating plate. The parameter requirements for the oxide layer of the fully oxidized area 1 and the oxidation unit 3 are:

[0043] Thickness: Oxide layer thickness 60~70um;

[0044] Withstand voltage: minimum breakdown voltage 1200V;

[0045] Corrosion resistance: passed the 336-hour 5% hydrochloric acid test;

[0046] Density: Surface density 1100mg / dm 2 ;

[0047] Hardness: Hardness Hv not less than 400.

[0048] In this embodiment, the partially oxidized area 2 in the middle of the front side of the heating plate is a symmetrical figure; wherein, Figure 1 is an embodiment of the present application, and its partially oxidized area 2 is a rectangle; Figure 2 is another embodiment of the present application, and its partially oxidized area 2 is a rectangle with chamfers, and the chamfers can be straight or arc-shaped; Figure 3 is another embodiment of the present application, and its partially oxidized area 2 is circular.

[0049] The hot wires arranged on the back are also part of the heating plate. This application has no requirements for the arrangement of the hot wires, and is not limited to whether they are arranged evenly or symmetrically. You can choose according to the specific situation.

[0050] In some embodiments of the present application, the proportion of the partially oxidized area 2 on the front of the heating plate to the entire front area of ​​the heating plate can be adjusted accordingly based on the number and arrangement of silicon wafers on the coating substrate, preferably ranging from 50% to 80%. When the proportion of the partially oxidized area to the front area of ​​the heating plate is less than 50% or greater than 80%, it is impossible to accurately control the thermal emissivity of the surrounding areas and the central area of ​​the heating plate, making it difficult to achieve temperature control of the heated carrier plate, and it is impossible to reduce the temperature difference between silicon wafers on the same substrate to achieve the purpose of improving the uniformity of the coating.

[0051] In some embodiments of the present application, the shape of the oxidation unit 3 can be rectangular (as shown in Figures 1-3), circular (as shown in Figure 4), or long strip (as shown in Figure 5). The area of ​​the oxidation unit 3 decreases from the periphery to the center, or is evenly distributed within the partial oxidation region 2.

[0052] It should be pointed out that the oxidation treatment of the present application can also be changed to spraying treatment or plating treatment, that is, a spray layer or plating layer is set in the above-mentioned oxidation area, and after the spraying treatment and plating treatment, the surrounding area and the middle area of ​​the heating device have different thermal emissivity to achieve the effect achieved during the above-mentioned oxidation treatment.

[0053] In some embodiments of the present application, the peripheral region and the middle region are surface treated by at least one of oxidation, wet treatment, coating, plating, sandblasting, brushing, melt-blowing, and polishing. The surface treatment methods of the peripheral region and the middle region can be the same or different.

[0054] In a more specific embodiment, the surface treatment method of the peripheral area and the middle area is at least one of oxidation, coating and plating, and the thickness of the film layer formed on the surface is 1-500 um.

[0055] In a more specific embodiment, the surface treatment method is melt-blowing, and after the treatment, a thermal emissivity regulating film layer is formed on the surface of the heating plate; the thickness of the film layer is 0.5 mm to 10 mm.

[0056] In other embodiments of the present application, as shown in Figure 6 , a heating device includes a heating plate and an energy supply unit (not shown). The energy supply unit is connected to the heating plate and is used to provide energy to the heating plate for heating. The heating plate includes a first region located on the periphery and a second region located in the center. Both the first and second regions are coated with a patterned layer for regulating the thermal emissivity of the heating plate.

[0057] In this embodiment, the coverage of the patterned layer in the first region can be greater than the coverage of the patterned layer in the second region. Specifically, the coverage of the patterned layer in the first region is constant, and the coverage of the patterned layer in the second region is also constant, so that the thermal emissivity of the first region and the second region of the heating plate are both constant. Alternatively, the coverage of the patterned layer in the first region and the patterned layer in the second region both decreases from the periphery to the center; or alternatively, the coverage of the patterned layer in the first region or the patterned layer in the second region changes gradually from the periphery to the center, so that the thermal emissivity of the corresponding region changes gradually, while the thermal emissivity of the other region is constant.

[0058] In the above embodiment, no matter whether the thermal emissivity of the first region and the second region is constant or gradually changes, the thermal emissivity of the first region (ie, the peripheral region) is different from the thermal emissivity of the second region (ie, the middle region).

[0059] In other embodiments of the present application, the thermal emissivity of the surrounding area increases from the edge to the center, and the thermal emissivity of any position in the surrounding area is smaller than that of the middle area.

[0060] In other embodiments of the present application, as shown in FIG7 , a heating device includes a heating plate and an energy supply unit (not shown). The energy supply unit is connected to the heating plate and is used to provide energy to the heating plate for heating. The heating plate includes a first region located at the periphery and a second region located in the center. The surfaces of the first and second regions are provided with coatings of different shapes, such that the thermal emissivity of the peripheral regions of the heating plate is different from that of the central region of the heating plate.

[0061] In other embodiments of the present application, a heating device includes a heating plate and an energy supply unit, the energy supply unit being connected to the heating plate and configured to provide energy to the heating plate for heating. The heating plate includes a first region located at the periphery and a second region located in the center. The surfaces of the first region and the second region are configured with different roughnesses, wherein the roughness of the peripheral region of the heating plate is different from the roughness of the central region of the heating plate, thereby causing the thermal emissivity of the peripheral region of the heating plate to be different from the thermal emissivity of the central region of the heating plate.

[0062] In addition, in some other embodiments of the present application, the first area and the second area of ​​the heating plate may be adjacent, as shown in Figure 1, or they may not be adjacent, that is, when the first area and the second area are not adjacent, there may be a third area between the first area and the second area of ​​the heating plate, and the thermal emissivity of the third area may also be adjusted accordingly. Preferably, the thermal emissivity of the third area is between the thermal emissivity of the surrounding areas and the thermal emissivity of the middle area, which will not be further explained here.

[0063] It should be noted that the principle of cooperation between the energy supply unit and the heating plate, as well as the specific connection method, control method, etc. can all refer to the existing technology. This embodiment does not limit this and will not be described in detail here.

[0064] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0065] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. A heating device for vacuum coating equipment, comprising a heating plate, characterized in that: The heating plate includes surrounding areas and a middle area; The surrounding areas and the middle area have different thermal radiation rates, so as to achieve heating of the corresponding areas of the coated substrate so that the temperature difference of each part of the coated substrate is within a preset range.

2. The heating device of the vacuum coating equipment according to claim 1, characterized in that: The surrounding area and the middle area obtain different thermal emissivity after surface treatment; the surface treatment method is at least one of oxidation, wet treatment, coating, plating, sandblasting, wire drawing, melt spraying and polishing.

3. The heating device of the vacuum coating equipment according to claim 2, characterized in that: The surface treatment method is at least one of oxidation, coating and plating, and after the treatment, a thermal emissivity regulating film layer is formed on the surface of the heating plate; the thickness of the film layer is 1μm~500μm.

4. The heating device of the vacuum coating equipment according to claim 2, characterized in that: The surface treatment method is melt-blowing, and after the treatment, a thermal emissivity regulating film layer is formed on the surface of the heating plate; the thickness of the film layer is 0.5 mm to 10 mm.

5. The heating device of the vacuum coating equipment according to claim 2, characterized in that: The surrounding area and the middle area adopt the same or different surface treatment methods; The surface treatment coverage of the surrounding area is different from the surface treatment coverage of the middle area.

6. The heating device of the vacuum coating equipment according to claim 2, characterized in that: The surface treatment coverage of the surrounding area is 100%.

7. The heating device of the vacuum coating equipment according to claim 1, characterized in that: The thermal emissivity of the surrounding area decreases from the edge to the center, and the thermal emissivity of the surrounding area is greater than the thermal emissivity of the middle area; Alternatively, the thermal emissivity of the surrounding areas increases from the edge to the center, and the thermal emissivity of the surrounding areas is less than the thermal emissivity of the middle area.

8. The heating device of the vacuum coating equipment according to claim 2, characterized in that: The surface treatment methods adopted for the surrounding area and the middle area are both roughening treatment, so that the surfaces of the surrounding area and the middle area are set with different roughness.

9. A vacuum coating device, characterized in that: A heating device comprising the vacuum coating equipment as claimed in any one of claims 1 to 7.

10. A heating method for vacuum coating equipment, using the heating device of vacuum coating equipment as claimed in any one of claims 1 to 7 to heat the coating substrate in the vacuum chamber, wherein the heating device comprises a heating plate, characterized in that: The heating plate includes surrounding areas and a middle area; The temperature of the surrounding area and the middle area of ​​the coating substrate is regulated by controlling the thermal radiation rate of the surrounding area and the middle area.

11. The heating method of vacuum coating equipment according to claim 10, characterized in that: The method for controlling the thermal emissivity of the surrounding area and the middle area is: the heating plate is treated by at least one surface treatment method selected from oxidation, coating, plating, sandblasting and polishing, so that the surrounding area and the middle area of ​​the heating plate have different thermal emissivity.

Images