Heat dissipation device and method of etching machine table and etching machine table

Abstract

The invention provides a heat dissipation device and method of an etching machine and the etching machine, and relates to the technical field of semiconductor manufacturing, and the heat dissipation device comprises a detection unit which is used for detecting the temperature of an upper cover; the spraying device is arranged above the upper cover and used for spraying gas to the upper cover according to the temperature of the upper cover, so that the temperature of the upper cover is kept within a preset temperature range; and the air supply device is connected with the spraying device and is used for supplying air to the spraying device. According to the heat dissipation equipment, the spraying device is additionally arranged above the upper cover of the cavity, and the spraying device can spray the gas to the upper cover according to the temperature of the upper cover in the etching process, so that the temperature of the upper cover is kept within the preset temperature range. On the premise that an etching machine table mechanism is not changed, the temperature of the corresponding area of the cavity upper cover is effectively controlled, the etching rate is stabilized, and the improvement cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular, to a heat dissipation device and method for an etching machine stage, and an etching machine stage. Background Art

[0002] An etching machine stage is an essential semiconductor production device for the etching process, mainly used for etching materials such as single crystal silicon and polycrystalline silicon. The etch rate (ER) is one of the important parameters of the etching process, and its stability is crucial for the consistency and yield of the process.

[0003] In the traditional technology, the upper cover (Disk) of the etching chamber is relatively close to the process environment. During the etching process, the temperature of the upper cover rises with the time of plasma etching, which results in large fluctuations in the temperature of the upper cover and affects the etching rate. Summary of the Invention The purpose of the present invention is to provide a heat dissipation device and method for an etching machine stage, and an etching machine stage, so as to overcome the problem in the traditional technology that the temperature of the upper cover of the etching chamber fluctuates greatly and affects the etching rate.

[0004] In a first aspect, the present application provides a heat dissipation device for an etching machine stage. The etching machine stage includes a chamber and a top cover, the chamber is accommodated in the top cover, the chamber includes an upper cover, and the heat dissipation device includes: A detection unit for detecting the temperature of the upper cover; A spraying device arranged above the upper cover for spraying gas onto the upper cover according to the temperature of the upper cover, so that the temperature of the upper cover is maintained within a preset temperature range; A gas supply device connected to the spraying device for supplying gas to the spraying device.

[0005] In one embodiment, the spraying device includes: A bracket supported on the chamber; A nozzle head arranged on the bracket, and a plurality of nozzles are annularly arrayed on the nozzle head.

[0006] In one embodiment, a plurality of guiding grooves are formed inside the nozzle head, and each nozzle is uniformly distributed along the extending direction of the guiding groove; wherein, the shape and path of the guiding groove are designed by analyzing the temperature data of the upper cover. In one embodiment, the detection unit includes a temperature sensor, and the temperature sensor adopts a non-contact sensor.

[0007] In one embodiment, the gas supply device includes: A pipeline for providing a gas passage; A flow controller is disposed on the pipeline and is used to adjust the gas flow rate of the gas passage.

[0008] In one embodiment, the heat dissipation device further includes: A control unit, connected to the detection unit and the flow controller, is configured to output a control signal to the flow controller according to the temperature of the upper cover, so that the flow controller adjusts the gas flow rate according to the control signal. In a second aspect, the present application provides a heat dissipation method for an etching machine tool, which is applicable to the heat dissipation device described in any one of the first aspects. The method includes: During the process of etching a wafer, obtain the temperature of the upper cover of the cavity, and spray gas onto the upper cover according to the temperature of the upper cover, so that the temperature of the upper cover is maintained within a preset temperature range. In one embodiment, the spraying gas onto the upper cover according to the temperature of the upper cover includes: Calculate the flow rate values required to maintain the preset temperature range at different time nodes according to the corresponding relationship curve between temperature and etching time; wherein, the corresponding relationship curve is constructed based on the historical temperature data of the etching machine tool; Spray gas onto the upper cover according to the flow rate values.

[0009] In one embodiment, the method further includes: Pre-obtain the historical temperature data of the upper cover; Obtain the temperature distribution of different regions of the upper cover according to the historical temperature data; Design the shape and path of the guiding groove in the nozzle according to the temperature distribution.

[0010] In a third aspect, the present application provides an etching machine tool, including: A cavity, including an upper cover, and the cavity is used to accommodate a wafer; A top cover, covering the cavity; The heat dissipation device described in any one of the first aspects, which is configured to spray gas onto the upper cover according to the temperature of the upper cover during the process of etching a wafer, so that the temperature of the upper cover is maintained within a preset temperature range.

[0011] The above-mentioned heat dissipation device, method and etching machine tool of the etching machine tool have at least the following advantages: The heat dissipation device of the present application is provided with a spraying device above the upper cover of the cavity. During the etching process, the spraying device can spray gas onto the upper cover according to the temperature of the upper cover, so that the temperature of the upper cover is maintained within a preset temperature range. Without changing the structure of the etching machine tool, the present application effectively controls the temperature of the corresponding area of the upper cover of the cavity, stabilizes the etching rate, and reduces the transformation cost. Brief Description of the Drawings

[0012] Figure 1 is a structural block diagram of a conventional etching machine in an embodiment; Figure 2 is a schematic diagram showing the change of the temperature of the upper cover with the etching time in an embodiment; Figure 3 is a schematic diagram showing the change of the temperature and etching rate of the upper cover with the etching time respectively in an embodiment; Figure 4 is a schematic structural diagram of an injection device in an embodiment; Figure 5 is an exploded view of a heat dissipation device in an embodiment; Figure 6 is a comparison diagram of the temperature and etching rate before and after installing the heat dissipation device in an embodiment.

[0013] Reference Numerals in the Drawings: 1, top cover; 2, cavity; 3, upper cover; 4, bracket; 5, nozzle; 6, pipeline; 7, flow controller. Detailed Description of the Embodiment

[0014] For the convenience of understanding the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the understanding of the disclosure of the present application is more thorough and comprehensive.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of the present application in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0016] In the case of using "including", "having", and "comprising" described herein, unless an explicit limiting term is used, such as "only", "consisting of", etc., another component can also be added. Unless otherwise mentioned, terms in the singular form can include the plural form and should not be construed as having a quantity of one.

[0017] It should be understood that although terms such as "first" and "second" may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present application, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element.

[0018] In the present application, unless otherwise clearly specified and defined, terms such as "connected" and "coupled" should be understood in a broad sense. For example, it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0019] Please refer to Figure 1 , in one embodiment, the present application provides a heat dissipation device for an etching machine tool. The structure of a traditional etching machine tool is as Figure 1 shown. The etching machine tool includes a top cover 1 and a cavity 2. The cavity 2 includes an upper cover 3. During installation, the cavity 2 is accommodated within the top cover 1 and is completely covered by the top cover 1.

[0020] The heat dissipation device for the etching machine tool of the present application includes: a detection unit, a spraying device, and a gas supply device.

[0021] The detection unit is disposed around the upper cover 3 and is used to detect the temperature of the upper cover 3.

[0022] Specifically, the detection unit may be disposed near the upper cover or on the surface of the upper cover. Optionally, the detection unit includes a temperature sensor, and the temperature sensor adopts a non-contact sensor. Further, the number of temperature sensors may be multiple, so that the temperatures of different regions of the upper cover 3 can be detected.

[0023] The spraying device is disposed above the upper cover 3 and is used to spray gas onto the upper cover 3 according to the temperature of the upper cover 3 so as to keep the temperature of the upper cover 3 within a preset temperature range.

[0024] Please refer to Figure 2 and Figure 3 , Figure 2 as shown in the schematic diagram of the temperature (T) of the upper cover 3 changing with the etching time (t); Figure 3The figure shows the schematic diagrams of the temperature of the upper cover 3 (Disk) and the etching rate (ER) varying with the etching time (t) respectively. Since the cavity 2 of the etching machine is accommodated within the top cover 1, the upper cover of the cavity is relatively close to the process environment. During the etching process, the temperature of the upper cover 3 increases from 85°C to 155°C as the etching time increases, and the temperature fluctuation range is relatively large. High temperature can cause the photoresist on the wafer surface to burn, which may lead to phenomena such as photoresist mask failure, carbon residue hindering the reaction, and plasma interference, thus greatly affecting the etching rate. From Figure 3 It can be seen that as the temperature of the upper cover 3 rises, the etching rate (ER) decreases significantly, from 4600 to 3600. Based on this, in this application, by setting up a spraying device, the temperature of the upper cover 3 is maintained within a preset temperature range to avoid the above situation. Exemplarily, controlling the temperature of the upper cover 3 within 120°C can effectively avoid the phenomenon of photoresist burning. Further, the preset temperature range in the embodiments of this application is set to 90 - 110°C. This temperature range can also prevent the phenomenon of photoresist burning without affecting the normal etching process.

[0025] A gas supply device, connected to the spraying device, for supplying gas to the spraying device.

[0026] Specifically, the gas provided by the gas supply device can use pre-cooled clean dry air (CDA) or high-purity nitrogen as the cooling medium. Such gases can absorb the heat of the upper cover 3 when sprayed at low temperature and do not introduce pollution.

[0027] For the above-mentioned heat dissipation device of the etching machine, a spraying device is additionally provided above the upper cover 3 of the cavity 2. During the etching process, the spraying device can spray gas onto the upper cover 3 according to the temperature of the upper cover 3, so that the temperature of the upper cover is maintained within a preset temperature range. Without changing the structure of the etching machine, this application effectively controls the temperature of the corresponding area of the upper cover 3 of the cavity and stabilizes the etching rate.

[0028] Please refer to Figure 4 , the spraying device includes: a bracket 4 and a nozzle head 5.

[0029] The bracket 4 is supported on the cavity 2.

[0030] The nozzle head 5 is arranged on the bracket 4. A plurality of nozzles are annularly arrayed on the nozzle head 5. The gas provided by the gas supply device passes through each nozzle and is sprayed onto the surface of the upper cover 3, enabling heat exchange between the gas and the upper cover 3, thereby achieving the cooling purpose.

[0031] Exemplarily, the number of brackets 4 is four, and the four brackets 4 are evenly distributed in the edge area of the upper surface of the cavity 2. Adopting this scheme can ensure the stability of the bracket 4 and also avoid interference of the bracket 4 with the setting of the nozzles.

[0032] Optionally, the nozzle 5 can also be directly fixed on the inner wall of the top cover 1, which can further reduce costs while achieving the temperature control effect.

[0033] Optionally, a plurality of guiding grooves are formed inside the nozzle 5, and the spray holes are evenly distributed along the extending direction of the guiding grooves. By reasonably setting the shape and path of the guiding grooves, a region with high cooling efficiency can be formed locally to improve the temperature control effect. Among them, the shape and path of the guiding grooves are pre-set according to the temperature data of different regions of the upper cover 3 obtained by the detection unit. By analyzing the temperature data and constructing a thermal map, the temperature distribution of different regions of the upper cover 3 can be known. For the regions with higher temperatures, the guiding grooves can be designed in a curved or multi-channel shape to guide more gas through these regions to achieve a better cooling effect.

[0034] Optionally, the nozzle 5 has a circular structure, and a plurality of spray holes are formed on the circular structure, and the gas covers the surface of the upper cover 3 through each spray hole.

[0035] Optionally, air needles are arranged on each spray hole, and by adjusting the angles of the air needles, the hot spots can be accurately cooled.

[0036] For the heat dissipation device of the above-mentioned etching machine tool, the temperature data of different regions of the upper cover 3 is obtained by the detection unit, and the temperature distribution of the upper cover 3 is analyzed according to the temperature data. Then, according to the temperature distribution, the shape and path of the guiding grooves in the nozzle 5 are designed, and a region with high cooling efficiency can be formed locally, improving the temperature control effect.

[0037] Optionally, the gas supply device includes: a pipeline 6 and a flow controller 7.

[0038] One end of the pipeline 6 is connected to an external gas supply system, and the other end penetrates through the top cover 1 and is connected to the nozzle 5 to provide a gas passage. Among them, the gas supply system is used to provide cooled clean dry air or high-purity nitrogen.

[0039] The flow controller 7 is arranged on the pipeline 6 and is used to adjust the gas flow in the gas passage.

[0040] Optionally, the heat dissipation device of the above-mentioned etching machine tool further includes: a control unit.

[0041] The control unit is connected to the detection unit and the flow controller 7, and is used to output a control signal to the flow controller 7 according to the temperature of the upper cover 3, so that the flow controller 7 adjusts the gas flow according to the control signal.

[0042] Specifically, flow values corresponding to different time nodes are pre-stored in the control unit. During the etching process, for each time node, the control unit outputs a corresponding control signal. In this way, the flow controller 7 adjusts the gas flow to the corresponding flow value according to the control signal, so as to keep the temperature of the upper cover 3 within the preset temperature range. It should be noted that the above time nodes are determined according to the temperature change. For example, if the temperature change value does not exceed the preset range within a certain time, the above time is recorded as a time node.

[0043] Furthermore, the pre-stored flow values are obtained according to the historical temperature data of the etching machine. According to this historical temperature data, the temperature change data of the upper cover 3 during the etching process with respect to the etching time, as well as the temperature distribution information of different regions of the upper cover 3, can be analyzed. According to the temperature change data of the upper cover 3 with respect to the etching time, the corresponding relationship curve between the temperature and the etching time can be analyzed. This corresponding relationship curve reflects the temperature rising trend without gas intervention. By analyzing the rising trend, characteristic parameters such as the temperature rising rate and the critical temperature value can be extracted. According to the above characteristic parameters, an initial flow value can be preset for each time node. Through multiple experiments, the temperature response curve of each experiment is recorded, and the initial flow value is gradually adjusted according to the temperature response curve, so as to keep the temperature of the upper cover 3 within the preset temperature range.

[0044] During the etching process, the control unit can select the corresponding gas flow value according to the time node.

[0045] Furthermore, during the etching process, the control unit can also adjust the above flow value according to the temperature of the upper cover 3 obtained in real time according to the preset logic to achieve a better temperature control effect. Exemplarily, if the flow value corresponding to a time node is S1, and it is detected that the temperature of the upper cover 3 rises beyond the preset range, then the control unit adjusts the flow value S1 to S1 + △S according to the preset logic to increase the cooling effect.

[0046] For the heat dissipation device of the above-mentioned etching machine, the control unit outputs a control signal to the flow controller 7 at different time nodes according to the pre-stored flow values, so that the flow controller 7 correspondingly adjusts the gas flow to control the temperature of the upper cover 3. Furthermore, during the etching process, the control unit also obtains the temperature of the upper cover 3 in real time and adjusts the above pre-stored flow values according to the temperature of the upper cover 3 to achieve a better temperature control effect.

[0047] Please refer to Figure 5 , Figure 5 The explosion diagram of the heat dissipation device of the etching machine of the present application is shown below. The following will be described in detail with reference to Figure 5 the present application: Pre-acquire the historical temperature data of the etching machine. According to the historical temperature data, the corresponding relationship curve between temperature and etching time is parsed. Through multiple experiments based on the corresponding relationship curve, the flow rate value corresponding to each time node is calculated. At the same time, according to the historical temperature data, the temperature distribution information of different regions of the upper cover 3 can also be obtained. According to the temperature distribution information, the shape and path of the guiding groove inside the nozzle 5 are designed, so as to form a region with high local cooling efficiency and improve the temperature control effect.

[0048] During installation, first set the bracket 4 on the upper surface of the cavity 2, then set the nozzle 5 on the bracket 4, and then place the top cover 1 on the cavity 2. If the nozzle 5 is fixedly connected to the inner wall of the top cover 1, the top cover 1 can be directly placed on the cavity 2.

[0049] Further, insert the pipeline 6 through the top cover 1 into the nozzle 5. At this time, the flow controller 7 controls the pipeline 6 in the closed state.

[0050] After the etching starts, the control unit outputs control signals to the flow controller 7 at different time nodes according to the pre-stored flow rate values, so that the flow controller 7 adjusts the gas flow rate accordingly to maintain the temperature of the upper cover 3. During the etching process, the control unit also detects the temperature of the upper cover 3 in real time and adjusts the flow rate value according to the temperature to achieve a better temperature control effect.

[0051] After the etching ends, the control unit controls the pipeline 6 in the closed state and waits for the next etching process.

[0052] Please refer to Figure 6 , Figure 6 which is a comparison chart of temperature and etching rate before and after installing the heat dissipation device. Figure 6 The curve 1 shown is a schematic diagram of the temperature change of the upper cover 3 after installing the heat dissipation device, the curve 2 is a schematic diagram of the temperature change of the upper cover 3 before installing the heat dissipation device, the curve 3 is a schematic diagram of the change of the etching rate after installing the heat dissipation device, and the curve 4 is a schematic diagram of the change of the etching rate before installing the heat dissipation device. It can be seen from curves 1 and 2 that the temperature change range of the upper cover 3 before installing the heat dissipation device is about 90°C - 155°C, and the temperature change range after installing the heat dissipation device is about 70°C - 100°C, effectively controlling the temperature rise. It can be seen from curves 3 and 4 that before installing the heat dissipation device, as the temperature rises, the etching rate drops from 4700 to 3800; after installing the heat dissipation device, as the temperature rises, the etching rate drops from 4000 to 3600, effectively controlling the decline of the etching rate.

[0053] Based on the same inventive concept, an embodiment of the present application further provides a heat dissipation method for an etching machine tool, which is applicable to the heat dissipation device of the above-mentioned etching machine tool. The implementation solution provided by this heat dissipation method to solve the problem is similar to the implementation solution described in the above heat dissipation device. Therefore, the specific limitations in one or more of the following method embodiments can refer to the limitations on the device in the foregoing text and will not be repeated here.

[0054] In one embodiment, the heat dissipation method for the etching machine tool of the present application includes: During the process of etching the wafer, obtain the temperature of the upper cover of the cavity, and spray gas onto the upper cover according to the temperature of the upper cover, so that the temperature of the upper cover is maintained within a preset temperature range.

[0055] Optionally, spraying gas onto the upper cover according to the temperature of the upper cover includes: Calculate the flow rate values required to maintain the preset temperature range at different time nodes according to the corresponding relationship curve between the temperature and the etching time; wherein, the corresponding relationship curve is constructed based on the historical data of the etching machine tool; Spray gas onto the upper cover according to the flow rate values.

[0056] Optionally, the above heat dissipation method for the etching machine tool further includes: During the etching process, continuously obtain the temperature of the upper cover. When it is detected that the temperature of the upper cover rises beyond the preset range, adjust the flow rate value according to the preset logic.

[0057] Optionally, the above heat dissipation method for the etching machine tool further includes: Pre-obtain the historical temperature data of the upper cover; obtain the temperature distribution of different regions of the upper cover according to the historical temperature data; design the shape and path of the guiding groove inside the nozzle according to the temperature distribution.

[0058] For the above heat dissipation method of the etching machine tool, first obtain the corresponding relationship curve between the temperature and the etching time of the upper cover, as well as the temperature distribution of different regions of the upper cover according to the historical temperature data of the upper cover. Determine the flow rate values required to maintain the preset temperature range at different time nodes according to the corresponding relationship curve, and precisely control the temperature of the upper cover. Further, during the etching process, also adjust the above flow rate value in real time according to the temperature of the upper cover to achieve a better temperature control effect. Further, design the shape and path of the guiding groove inside the nozzle according to the temperature distribution, which can form a local high-cooling-efficiency area and further improve the temperature control effect.

[0059] Optionally, the present application further provides an etching machine tool, including: a top cover, a cavity, and a heat dissipation device.

[0060] The top cover covers the cavity.

[0061] The cavity includes an upper cover, and this cavity is used to accommodate the wafer.

[0062] A heat dissipation device is used to spray gas onto the upper cover according to the temperature of the upper cover during the etching of the wafer, so that the temperature of the upper cover is maintained within a preset temperature range. It should be noted that the structure and working principle of the heat dissipation device are the same as those of the heat dissipation device involved in the above embodiment. For the sake of brevity, they will not be described here again.

[0063] In the above etching machine tool, by setting a heat dissipation device, during the etching process, gas can be sprayed onto the upper cover according to the temperature of the upper cover, so that the temperature of the upper cover is maintained within a preset temperature range. Without changing the mechanism of the etching machine tool, this application effectively controls the temperature of the corresponding area of the cavity upper cover, stabilizes the etching rate, and reduces the transformation cost.

[0064] Please note that the above embodiments are for illustrative purposes only and do not imply any limitation to the present invention.

[0065] Each embodiment in this specification is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0066] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0067] The above embodiments only represent several implementation manners of this application. The description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent application. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of this application, several deformations and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this patent application should be subject to the appended claims.

Claims

1. A heat dissipation device for an etching machine tool, characterized in that, The etching machine includes a cavity and a top cover, the cavity is accommodated within the top cover, the cavity includes an upper cover, and the heat dissipation device includes: A detection unit for detecting the temperature of the upper cover; A spraying device disposed above the upper cover for spraying gas onto the upper cover according to the temperature of the upper cover, so that the temperature of the upper cover is maintained within a preset temperature range; A gas supply device connected to the spraying device for supplying gas to the spraying device.

2. The heat dissipation device according to claim 1, wherein The spraying device includes: A bracket supported on the cavity; A nozzle head disposed on the bracket, and a plurality of nozzles are annularly arrayed on the nozzle head.

3. The heat dissipation device according to claim 2, characterized in that A plurality of guiding grooves are formed inside the nozzle head, and each of the nozzles is uniformly distributed along the extending direction of the guiding groove; wherein, the shape and path of the guiding groove are designed by analyzing the temperature data of the upper cover.

4. The heat dissipation device according to claim 1, wherein The detection unit includes a temperature sensor, and the temperature sensor adopts a non-contact sensor.

5. The heat dissipation device according to claim 1, wherein The gas supply device includes: A pipeline for providing a gas passage; A flow controller disposed on the pipeline for adjusting the gas flow rate of the gas passage.

6. The heat dissipation device according to claim 5, wherein, It further includes: A control unit connected to the detection unit and the flow controller for outputting a control signal to the flow controller according to the temperature of the upper cover, so that the flow controller adjusts the gas flow rate according to the control signal.

7. A heat dissipation method for an etching machine tool, characterized in that, Applicable to the heat dissipation device according to any one of claims 1-6, the method includes: During the process of etching a wafer, obtaining the temperature of the upper cover of the cavity and spraying gas onto the upper cover according to the temperature of the upper cover, so that the temperature of the upper cover is maintained within a preset temperature range.

8. The heat dissipation method according to claim 7, wherein The spraying gas onto the upper cover according to the temperature of the upper cover includes: Calculating the flow rate values required to maintain the preset temperature range at different time nodes according to the corresponding relationship curve between temperature and etching time; wherein, the corresponding relationship curve is constructed based on the historical temperature data of the etching machine; Spraying gas onto the upper cover according to the flow rate values.

9. The heat dissipation method according to claim 7, characterized in that The method further includes: Pre-obtaining the historical temperature data of the upper cover; Obtaining the temperature distribution of different regions of the upper cover according to the historical temperature data; Designing the shape and path of the guiding groove inside the nozzle head according to the temperature distribution.

10. An etching machine, characterized in that, It includes: A cavity including an upper cover, and the cavity is used for accommodating a wafer; A top cover covering the cavity; The heat dissipation device according to any one of claims 1-6, which is used to spray gas onto the upper cover according to the temperature of the upper cover during the process of etching a wafer, so that the temperature of the upper cover is maintained within a preset temperature range.

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