Carrier plate heating method for vacuum coating equipment and carrier plate

Abstract

The invention discloses a carrier plate heating method for vacuum coating equipment and a carrier plate, and is applied to the field of vacuum coating. The method comprises the following steps: in the vacuum coating equipment, firstly depositing a heat absorption film layer on the back surface of the carrier plate, and then heating the back surface of the coated carrier plate. Therefore, the temperature rise efficiency of the carrier plate can be obviously improved.

Description

Technical Field

[0001] The present application relates to the field of vacuum coating, and particularly to a method for heating a carrier plate for a vacuum coating device and the carrier plate. Background Art

[0002] Vacuum coating is a key process for manufacturing solar cells. TOPCon (Tunnel Oxide Passivated Contact) cells, HJT (Heterojunction) cells, and XBC (Interdigitated Back Contact) cells all involve vacuum coating during the manufacturing process. As an important component in the vacuum coating device, the carrier plate not only plays a role in carrying substrates (such as silicon wafers), but also the temperature of the carrier plate will affect the vacuum coating process and the coating quality.

[0003] During mass production on the production line, the carrier plate needs to be preheated within a limited beat to ensure coating uniformity and process stability. The traditional way to heat the carrier plate is by radiation heating with a heater, but the high heat capacity and low infrared radiation absorption rate of the carrier plate material result in insufficient heating rate, making it difficult to match the production beat and becoming a bottleneck restricting efficiency.

[0004] At present, methods to increase the heating rate of the carrier plate include increasing the heater power, shortening the distance between the heater and the carrier plate, and treating the surface of the carrier plate with a coating. Although increasing the heater power can improve the heating rate of the carrier plate to a certain extent, due to the high reflectivity characteristics determined by the carrier plate's own material, the carrier plate has a low absorption efficiency of the heater radiation and cannot fully absorb the heat radiated by the heater. This not only fails to fully achieve rapid heating of the carrier plate but also has a serious impact on the lifespan of the heater, increasing the maintenance cost. Shortening the distance between the heater and the carrier plate can also improve the heat radiation absorption efficiency of the carrier plate to a certain extent, but limited by the limited cavity space of the vacuum coating device, this method cannot completely solve the problem. Currently, the surface coating treatment of the carrier plate mostly uses spraying a silicon carbide (SiC) coating on the surface of the carrier plate, but this method has problems such as coating peeling and contaminating the process chamber, or poor roughness leading to easy absorption of water vapor, higher processing difficulty, and higher time cost. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a method for heating a carrier plate for a vacuum coating device and the carrier plate.

[0006] In a first aspect, an embodiment of the present application provides a method for heating a carrier plate for a vacuum coating device. The method includes: in the vacuum coating device, first depositing a heat-absorbing film layer on the back surface of the carrier plate, and then heating the back surface of the coated carrier plate. Among them, the heat absorption capacity of the heat-absorbing film layer is better than that of the carrier plate before coating.

[0007] In some embodiments, the infrared absorption rate of the heat-absorbing film layer is not less than 80%, and the heating is an infrared heating method.

[0008] In some embodiments, the heat-absorbing film layer is a semiconductor film layer, a metal film layer or a ceramic film layer, and the heating is an infrared heating method.

[0009] In some embodiments, the heat-absorbing film layer is any one of an amorphous silicon film layer, a microcrystalline silicon film layer, a silicon oxide film layer, and a silicon nitride film layer, and the heating is an infrared heating method.

[0010] In some embodiments, the thickness of the heat-absorbing film layer is 0.1 - 3 μm.

[0011] In some embodiments, the carrier plate is an aluminum-silicon alloy carrier plate.

[0012] In some embodiments, the vacuum coating equipment is a hot wire CVD equipment. In some embodiments, during the deposition process, the silane flow rate is 1000 - 2000 sccm, the hydrogen flow rate is 1000 - 3000 sccm, the air pressure is 5 - 10 Pa, and the hot wire temperature is not lower than 1800 °C. In some embodiments, during the heating process, the air pressure in the heating chamber is 5×10-4 Pa, and the hot wire power is 15 kW.

[0013] In a second aspect, an embodiment of the present application provides a carrier plate for a vacuum coating equipment, the back surface of the carrier plate has a heat-absorbing film layer formed by a deposition process, and the carrier plate is used for the heating step of the method as described in the first aspect.

[0014] The technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0015] (1) By pre-depositing a heat-absorbing film layer on the back surface of the carrier plate, the heating rate of the carrier plate is significantly increased, and the production efficiency is greatly improved;

[0016] (2) There is no need to shorten the distance between the heater and the carrier plate, nor to increase the heater power. Correspondingly, not only can the efficiency of the carrier plate absorbing heat radiation be greatly improved, but also the service life of the heater can be extended;

[0017] (3) The carrier plate can quickly and stably heat up to the specified temperature, avoiding temperature fluctuations caused by slow heating, providing a stable temperature environment for subsequent coating processes such as depositing amorphous silicon and doped microcrystalline silicon layers of a heterojunction in a process chamber, which is beneficial to improving the uniformity and quality of the film layers obtained in subsequent coating processes, and thus improving the performance of products (such as heterojunction batteries);

[0018] (4) Since the heat-absorbing film is deposited on the back surface of the carrier plate to increase the heating rate, and the coating of the substrate (such as a silicon wafer) is on the front surface of the carrier plate, it will not affect the normal process;

[0019] (5) By using a heat-absorbing film layer (such as an amorphous silicon film layer), the heat loss of the carrier plate is reduced, improving the heat utilization rate. Under the condition of achieving the same heating effect, the heating power of the heating wire can be appropriately reduced or the heating time can be shortened, thereby reducing the energy consumption in the production process and saving production costs.

[0020] (6) The solution is compatible with existing production line equipment and does not require hardware modification. Description of the Drawings

[0021] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application and, together with the specification, are used to explain the principles of the present application.

[0022] Figure 1 It is a flowchart of the method for heating the carrier plate of the vacuum coating equipment provided by the embodiment of the present application.

[0023] Figure 2 It is a schematic layout diagram of the carrier plate and the heating wire.

[0024] Figure 3 It is the correspondence between the heating rate of the carrier plate and the thickness of the film layer on the back surface of the carrier plate under the set conditions. Detailed Embodiments

[0025] In order to more clearly understand the above objects, features, and advantages of the present application, the embodiments of the present application will be further described below. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0026] Many specific details are set forth in the following description to facilitate a thorough understanding of the present application, but the present application may be practiced in other ways different from those described herein. Obviously, the embodiments in the specification are only a part of the embodiments of the present application, rather than all of the embodiments.

[0027] In the present application, the front side of the carrier plate refers to the side on which the substrate (such as a silicon wafer) is placed, and the other side is the back side. After the carrier plate is preheated, the substrate (such as a silicon wafer) on the carrier plate is coated. The method provided by the embodiment of the present application is particularly applicable to carrier plates with poor heat absorption performance. For example, an aluminum-silicon alloy carrier plate with an infrared absorption rate of only 10%.

[0028] Figure 1 It is a flowchart of the method for heating the carrier plate of the vacuum coating equipment provided by the embodiment of the present application. In the present application, the vacuum coating equipment includes, but is not limited to, a hot wire CVD (chemical vapor deposition) equipment. As Figure 1 shown, process 100 includes step 110 and step 120.

[0029] Step 110: Deposit a heat-absorbing film layer on the back of the carrier plate in a vacuum coating equipment. The chamber for coating can be called the process chamber, that is, step 110 is carried out in the process chamber of the vacuum coating equipment. The heat absorption capacity of the heat-absorbing film layer is better than that of the carrier plate before coating. For example, when the heating method of the carrier plate is infrared heating, the heat-absorbing film layer is a non-silicon film layer with high infrared absorption rate, and the carrier plate is an aluminum-silicon alloy carrier plate with low infrared absorption rate.

[0030] Step 120: Heat the back of the coated carrier plate in a vacuum coating equipment. The chamber for heating can be called the heating chamber, that is, step 120 is carried out in the heating chamber of the vacuum coating equipment. When the process chamber and the heating chamber of the vacuum coating equipment are not the same chamber, after moving the carrier plate with the back coated to the heating chamber, the back of the carrier plate needs to be heated by a heater (such as a heating wire).

[0031] Figure 2 It is a layout diagram of the carrier plate and the heating wire. Figure 2 The inner blue rectangle in [Figure] represents the carrier plate, that is Figure 2 Inside [Figure], there is a carrier plate array formed by arranging multiple carrier plates. The front / back of all carrier plates in each carrier plate array face in the same direction, that is, the backs of the carrier plates on the two carrier plate arrays face outward. Figure 2 Outside [Figure], there are two groups of heating wires. Each group of heating wires is used to heat the backs of the carrier plates in one carrier plate array.

[0032] The heat-absorbing film layer has a low thermal conductivity, can efficiently convert the radiant energy of the heater (such as a heating wire) into heat energy, and at the same time reduce the heat reflection loss on the surface of the carrier plate. Therefore, depositing a heat-absorbing film layer on the back of the carrier plate in advance can optimize the heat absorption and heat conduction characteristics of the carrier plate, thereby increasing the heating rate of the carrier plate. In other words, compared with the traditional uncoated carrier plate, the carrier plate with the back coated can reach the specified temperature in a shorter time. For example, under the same heating conditions of the heating wire, compared with the traditional uncoated carrier plate, the heating rate of the carrier plate coated with a certain thickness of non-silicon film can be increased by 30% - 50%, which can meet the production requirements of a 60-second beat and greatly improve the production efficiency.

[0033] It should be noted that depositing a heat-absorbing film layer on the back of the carrier plate in advance can not only increase the heating rate of the carrier plate, but also solve the problems existing in the existing heating solutions, including but not limited to: (1) Without increasing the power of the heater, the pre-treated carrier plate can fully absorb heat, which helps to extend the service life of the heater; (2) Without shortening the distance between the heater and the carrier plate, the efficiency of the carrier plate absorbing heat radiation can be greatly improved; (3) Compared with the coating technology, the film layer formed by the deposition technology is thinner, not easy to peel off and has better uniformity, which is beneficial to the efficient operation of the production line.

[0034] In some embodiments, when the infrared heating method is adopted in step 120, the infrared absorptivity of the heat absorption film layer is not less than 80%.

[0035] In some embodiments, when the infrared heating method is adopted in step 120, the heat absorption film layer is a semiconductor film layer, a metal film layer or a ceramic film layer.

[0036] Taking the semiconductor film layer as an example, the heat absorption film layer can be any one of an amorphous silicon film layer, a microcrystalline silicon film layer, a silicon oxide film layer, and a silicon nitride film layer.

[0037] It should be noted that the method provided in the embodiments of the present application is not only applicable to improving the heating rate of the aluminum-silicon alloy carrier plate when depositing the amorphous silicon and doped microcrystalline silicon layers of the heterojunction in the hot wire CVD, but can also be extended to other vacuum coating equipment that requires rapid heating and uses the infrared heating method (or other thermal radiation heating methods). For example, in the process of preparing other semiconductor thin films, metal thin films or ceramic thin films, if a carrier plate material with low infrared absorptivity is used, the heating rate of the carrier plate can be increased by depositing a corresponding high infrared absorptivity film layer (such as other types of silicon-based thin films) on the back of the carrier plate to meet the rhythm and temperature requirements of different production processes.

[0038] In addition, for the application scenarios of carrier plates made of different materials, appropriate coating materials for the back of the carrier plate can also be selected according to their needs to achieve the purpose of rapid heating. For example, for scenarios with high requirements for wear resistance and corrosion resistance, a silicon nitride film layer can be selected. Another example is that for scenarios where oxidation prevention is required, a silicon oxide film layer can be selected, etc.

[0039] In some embodiments, during the deposition process, the silane flow rate is 1000 - 2000 sccm, the hydrogen flow rate is 1000 - 3000 sccm, the pressure is 5 - 10 Pa, and the hot wire temperature is not lower than 1800 °C.

[0040] In some embodiments, during the heating process, the pressure in the heating chamber is 5×10 -4 Pa, and the hot wire power is 15 kW.

[0041] In some embodiments, during the deposition process, the silane flow rate is 1000 - 2000 sccm, the hydrogen flow rate is 1000 - 3000 sccm, the pressure is 5 - 10 Pa, and the hot wire temperature is not lower than 1800 °C; and during the heating process, the pressure in the heating chamber is 5×10 -4 Pa, and the hot wire power is 15 kW.

[0042] In some embodiments, the thickness of the heat absorption film layer is 0.1 - 3 μm. The measured data shows that the heating rate of the carrier plate is positively correlated with the (back of the carrier plate) film layer thickness. Table 1 shows that when the pressure in the heating chamber is 5×10 -4The heating rate of an aluminum-silicon alloy carrier plate coated with amorphous silicon film layers of different thicknesses under the same conditions of Pa, a hot wire power of 15 kW, and a heating duration of 300 s.

[0043]

[0044]

[0045] Table 1

[0046] By comparing the heating rates of the carrier plates with different film thicknesses, it is proved that the amorphous silicon back film layer can significantly improve the hot wire heating efficiency. Figure 3 It shows the corresponding relationship between the heating rate of the carrier plate and the thickness of the back film layer of the carrier plate under the aforementioned conditions.

[0047] In some embodiments, after performing step 110 once, step 120 can be repeatedly executed. That is, the coated (back side) carrier plate can be recycled. Table 2 shows the verification data of the long-term stability of the coated carrier plate.

[0048] Number of cycles Heating rate decay rate % Film layer peeling area % 100 0.6 ＜0.1 500 1.4 0.7 1000 2.8 1.5

[0049] Table 2

[0050] It can be seen that the coated carrier plate still meets the process requirements (heating rate decay rate < 3%) after 1000 cycles, and its stability far exceeds that of the traditional uncoated carrier plate (which fails after 200 cycles).

[0051] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent in the said process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0052] The above are only the embodiments of the present application, and the embodiments enable those skilled in the art to understand and implement the present application. Various modifications to the embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and features disclosed herein.

Claims

1. A method for heating a carrier plate of a vacuum coating equipment, characterized in that, Including: In the vacuum coating equipment, an endothermic film layer is deposited on the back of the carrier plate; the heat absorption capacity of the endothermic film layer is better than that of the carrier plate before coating; In the vacuum coating equipment, the back of the coated carrier plate is heated.

2. The method according to claim 1, wherein The infrared absorption rate of the endothermic film layer is not less than 80%, and the heating is by infrared heating.

3. The method according to claim 1, wherein The endothermic film layer is a semiconductor film layer, a metal film layer or a ceramic film layer, and the heating is by infrared heating.

4. The method according to claim 1, characterized in that The endothermic film layer is any one of an amorphous silicon film layer, a microcrystalline silicon film layer, a silicon oxide film layer, and a silicon nitride film layer, and the heating is by infrared heating.

5. The method according to claim 1, wherein The thickness of the endothermic film layer is 0.1 - 3 μm.

6. The method according to claim 1, wherein The carrier plate is an aluminum-silicon alloy carrier plate.

7. The method according to any one of claims 1 to 6, characterized in that The vacuum coating equipment is a hot wire CVD equipment.

8. The method according to claim 7, wherein During the deposition process, the silane flow rate is 1000 - 2000 sccm, the hydrogen flow rate is 1000 - 3000 sccm, the air pressure is 5 - 10 Pa, and the hot wire temperature is not lower than 1800 °C.

9. The method according to claim 8, characterized in that, During the heating process, the air pressure in the heating chamber is 5×10 -4 Pa, and the power of the heating wire is 15 kW.

10. A carrier plate for a vacuum coating device, characterized in that, The back of the carrier plate has an endothermic film layer formed by a deposition process, and the carrier plate is used in the heating step of the method according to any one of claims 1 - 9.

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