Etching apparatus and its control method
By controlling the pressure regulation and air pump circulation of the etching device, the problems of corrosion damage to the etching solution pump bellows and difficulty in discharging the etching solution were solved, thus achieving stable operation and safety of the etching device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZEUS
- Filing Date
- 2022-07-07
- Publication Date
- 2026-05-26
AI Technical Summary
During the etching process, the bellows of the etching solution pump deforms due to pressure difference and temperature changes, resulting in frictional damage, and the etching solution is difficult to discharge smoothly, affecting the life and safety of the device.
The pressure is regulated by control components to ensure that the external and internal pressures of the bellows inside the etching solution pump are balanced, and an air pump is used to force gas circulation to ensure the smooth discharge of the etching solution.
It effectively prevents damage to the bellows, ensures stable operation of the etching solution pump, extends the life of the device, and enables smooth discharge of the etching solution.
Smart Images
Figure CN115602576B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an etching apparatus and a control method thereof, and more specifically, to an etching apparatus and a control method thereof capable of preventing damage to the bellows inside the etching solution pump that transfers the etching solution from the etching solution supply section of the etching apparatus to the etching chamber. Background Technology
[0002] Generally, semiconductor pretreatment processes include an etching process, which includes dry etching and wet etching.
[0003] Dry etching is primarily performed under vacuum after the addition of fluorine-based gases and inert gases. The equipment used for dry etching is expensive, thus limiting its industrial applications. Therefore, wet etching using phosphoric acid is more widely used compared to dry etching.
[0004] The wet etching process selectively etches the desired object layer in the object (substrate, etc.) through the chemical reaction of the etching solution. Depending on the required characteristics or degree of etching, an etching solution with matching components is mixed to perform the etching process.
[0005] The wet etching process offers improved operational compatibility compared to dry etching, can process a large number of objects at once, and has the advantage of low equipment cost.
[0006] However, during wet etching, a portion of the etching solution vaporizes, causing the temperature of the object to drop due to the heat of vaporization. Furthermore, controlling the concentration of the etching solution becomes difficult due to vaporization, resulting in potential losses. Therefore, there is a need for a method that prevents the vaporization of the etching solution in the etching section (e.g., comprising an etching chamber and an etching solution supply section) by applying pressure (i.e., the etching section is composed of a pressurization system that applies pressure at a specified pressure) to maintain a constant etching solution concentration.
[0007] However, when pressure is applied to the etching section as described above (i.e., when the etching section is constructed with a pressurized system), the following problems also exist: Under high temperature and pressure conditions, when the etching solution pump is driven, the pump bellows deforms (e.g., expands) due to the pressure difference and temperature between the inside and outside of the pump, resulting in contact with the inner wall of the pump (e.g., the internal guide). As the pump bellows continues to rub against the inner wall, component damage occurs (e.g., wear occurs at the friction points of the bellows), shortening the lifespan and reducing pump performance. In addition, a safety accident may eventually occur when the bellows breaks under high temperature and pressure conditions.
[0008] In addition, when pressure is applied to the etching section as described above, the pressure in the etching chamber and the etching solution supply section are the same, which makes it difficult to achieve natural discharge of the etching solution in the etching chamber (i.e., the etching solution in the etching chamber is discharged naturally to the etching solution supply section located at the bottom of the etching chamber by gravity, instead of using power, such as a pump that forces the etching solution from the etching chamber to the etching solution supply section).
[0009] As mentioned above, when the etching solution is not drained properly and the etching chamber is soaked in the etching solution, the process cannot be carried out. The etching solution seeps into the components connected to the etching chamber, causing corrosion or deformation and resulting in damage to the etched parts.
[0010] Therefore, a technology is needed that can prevent damage to the bellows inside the etching pump, which moves the etching solution from the etching solution supply section in the etching section to the etching chamber, and allows the etching solution to be smoothly and naturally discharged from the etching chamber to the etching solution supply section even when the etching section is pressurized.
[0011] The background technology of this invention is disclosed in Korean Patent No. 10-0691479 (granted on February 28, 2007, Etching apparatus for large-area substrate). Summary of the Invention
[0012] According to one aspect of the present invention, the present invention was developed to solve the problems described above, and its object is to provide an etching apparatus and a control method thereof, which enables the prevention of damage to the bellows inside the etching solution pump, the etching solution pump transferring the etching solution from the etching solution supply section of the etching apparatus to the etching chamber.
[0013] An etching apparatus according to one aspect of the present invention is characterized by comprising: an etching chamber for etching an object using an etching solution; an etching solution supply unit for recovering the etching solution in the etching chamber and supplying the etching solution to the etching chamber via an etching solution pump; a first pressure regulating unit for injecting gas into the etching solution pump to apply a driving pressure; a second pressure regulating unit for pressurizing the etching chamber and the etching solution supply unit at a specified same pressure; a back pressure regulating unit for regulating the pressure of the gas discharged when the etching solution pump is driven; and a valve for controlling the sequence and direction of the gas being injected into or discharged from the etching solution pump.
[0014] In this invention, the invention is characterized by further including a control unit, which selectively controls one or more of the first pressure regulating unit, the second pressure regulating unit, the valve, the etching solution pump, and the back pressure regulating unit to perform etching.
[0015] In this invention, the characteristic is that, in the second pressure regulating section, a new pipeline branching off from the pipeline connected to the etching section is connected to the back pressure regulating section, wherein the etching section includes the etching chamber and the etching solution supply section.
[0016] In this invention, the back pressure regulating part is also subjected to the same pressure as the pressure applied to the etching part from the second pressure regulating part through the new pipeline.
[0017] In this invention, the control unit controls the first pressure regulating unit to apply a pressure greater than the pressure applied to the back pressure regulating unit to the etching solution pump.
[0018] In this invention, the etching apparatus further includes a third pressure regulating unit, which independently applies pressure to the back pressure regulating unit, and the control unit controls the third pressure regulating unit to apply the same pressure to the back pressure regulating unit as the pressure applied to the etching unit by the second pressure regulating unit.
[0019] In this invention, the control unit controls the first pressure regulating unit to apply a higher pressure than that applied by the second or third pressure regulating unit.
[0020] In this invention, the gas discharge lines from the etching solution pump through the valve to different paths are merged into a single gas discharge line, and a back pressure regulating section is formed in the merged single gas discharge line.
[0021] In this invention, the etching solution supply unit is characterized in that the etching solution in the etching chamber is recovered by gravity-based natural discharge.
[0022] Another aspect of the present invention relates to a control method for an etching apparatus, characterized in that the etching apparatus comprises: an etching chamber; an etching solution supply unit that supplies etching solution to the etching chamber via an etching solution pump; a first pressure regulating unit that injects gas into the etching solution pump to apply a driving pressure; a second pressure regulating unit that pressurizes the etching chamber and the etching solution supply unit at a specified pressure; a back pressure regulating unit that regulates the pressure of the gas discharged when the etching solution pump is driven; a valve that controls the sequence and direction of injection or discharge into the etching solution pump; and a control unit, the control method of the etching apparatus comprising the steps of: the control unit selectively controlling one or more of the first pressure regulating unit, the second pressure regulating unit, the valve, the etching solution pump, and the back pressure regulating unit to perform etching; and the control unit controlling the first pressure regulating unit to apply a pressure greater than the pressure applied to the back pressure regulating unit to the etching solution pump.
[0023] In this invention, the method is characterized in that, in the second pressure regulating section, a new pipeline branching from the pipeline connected to the etching section is connected to the back pressure regulating section, wherein the etching section includes the etching chamber and the etching solution supply section; the method further includes the step of: the control section causing the same pressure applied to the etching section from the second pressure regulating section to also be applied to the back pressure regulating section.
[0024] In this invention, the etching apparatus further includes a third pressure regulating unit that independently applies pressure to the back pressure regulating unit; the method further includes the step of controlling the third pressure regulating unit to apply a pressure to the back pressure regulating unit that is the same as the pressure applied to the etching unit by the second pressure regulating unit.
[0025] In this invention, the method is characterized by the following step: the control unit controls the first pressure regulating unit to apply a pressure higher than that applied by the second pressure regulating unit or the third pressure regulating unit.
[0026] According to one aspect of the invention, the invention is able to prevent damage to the bellows inside the etching solution pump, which moves the etching solution from the etching solution supply section of the etching apparatus to the etching chamber. Attached Figure Description
[0027] Figure 1 This is an example diagram illustrating a simplified configuration of the etching apparatus according to a first embodiment of the present invention.
[0028] Figure 2 This is an example diagram illustrating a simplified configuration of an etching apparatus according to a second embodiment of the present invention.
[0029] Figure 3 It is used to describe the control of the Figure 2 A flowchart illustrating the operation of the etching apparatus.
[0030] Figure 4 In order to describe the Figure 1 An example diagram showing the operation of the etching solution pump is provided.
[0031] Figure 5 It is shown that Figure 1 An example diagram showing a more specific configuration of the etched portion.
[0032] Figure 6 It is used to describe the control of the Figure 5 A flowchart illustrating the operation of the etching apparatus shown. Detailed Implementation
[0033] An embodiment of the etching apparatus and control method of the present invention will now be described with reference to the accompanying drawings.
[0034] In the description, for clarity and convenience, the thickness of lines or the size of constituent elements shown in the figures may be enlarged. Furthermore, the terminology used below, defined with regard to the function in this invention, may vary depending on the user's intent or convention. Therefore, the definition of such terminology should be based on the entire contents of this specification.
[0035] Figure 1 This is an example diagram illustrating a simplified configuration of the etching apparatus according to a first embodiment of the present invention.
[0036] like Figure 1 As shown, the etching apparatus of the first embodiment of the present invention includes an etching unit 110, an etching liquid pump 120, a valve 130, a back pressure regulating unit 140, a first pressure regulating unit 150, a second pressure regulating unit 160, and a control unit 210.
[0037] The etching section 110 includes an etching chamber ( Figure 5 111) and etching solution supply unit ( Figure 5 112), formed for the etching chamber ( Figure 5 111) and the etching solution supply unit ( Figure 5 112) A pressurization system that pressurizes at the same specified pressure (see reference 112) Figure 5 ).
[0038] Figure 5 It is shown that Figure 1 A more specific example diagram of the structure of the etched portion will be described in detail when the method for improving the problem of the etched portion 110 is described.
[0039] Refer to Figure 1 The second pressure regulating unit 160 pressurizes the etching unit 110 at a specified pressure to form and maintain a pressurized atmosphere during object etching.
[0040] For example, the second pressure regulating unit 160 applies pressure to the etching unit 110 through a conduit 161 connected to the etching unit 110, and a new conduit 162 branching off from the conduit 161 is connected to the back pressure regulating unit 140. Therefore, the same pressure as that applied to the etching unit 110 is also applied to the back pressure regulating unit 140.
[0041] In the pressurized etching system of this embodiment, the etching solution pump 120 supplies (or circulates) the etching solution (or reagent) to (or circulates to) the etching section 110 (see reference). Figure 4 ).
[0042] Figure 4 In order to describe the Figure 1An example diagram showing the operation of the etching solution pump is provided.
[0043] Reference Figure 4 In order to achieve the suction operation of the first and second bellows symmetrically formed inside the etching liquid pump 120, the valve 130 (e.g., check valve) operates alternately (i.e., alternately) to allow gas (i.e., gas applied by the first pressure regulating unit) to flow into (inject) the gas chamber or to discharge the gas that has flowed into (injected) the gas chamber.
[0044] At this time, the gas may include clean air, such as N2, CO2, Ar, etc., but is not intended to be a limitation.
[0045] For example, when gas flows into the air chamber of the first bellows through the valve 130 (i.e., when gas flows into the air chamber of the first bellows from the first pressure regulating unit 150 through pipes 125 and 121), the first bellows is activated (suction), causing the etching solution to be discharged into the etching unit 110. At this time, the gas in the air chamber of the second bellows is discharged through the valve 130 (i.e., the gas in the air chamber of the second bellows is discharged through pipes 122 and 124 and the back pressure regulating unit 142).
[0046] Conversely, when gas flows into the air chamber of the second bellows through the valve 130 (i.e., when gas flows into the air chamber of the second bellows from the first pressure regulating unit 150 through pipes 125 and 122), the second bellows starts (suction) and discharges the etching solution. At this time, the gas in the air chamber of the first bellows is discharged through the valve 130 (i.e., the gas in the air chamber of the first bellows is discharged through pipes 121 and 123 and back pressure regulating unit 141).
[0047] The back pressure regulating units 141 and 142 are used to regulate the external pressure of the etching solution pump 120. When gas is discharged from the etching solution pump 120, it is discharged when the external pressure of the pump (e.g., the pressure surrounding the bellows) is higher than the pressure applied to the back pressure regulating units 141 and 142, thereby keeping the internal pressure of the etching solution pump 120 (e.g., the pressure of the bellows being pushed by the pressurized etching solution) fixed.
[0048] At this point, in this embodiment, as Figure 4 As shown in (a), the gas discharged by the etching solution pump 120 can be discharged through different paths via multiple back pressure regulating units 141, 142. However, to save costs, such as Figure 4 As shown in (b), the gas discharge pipes 123 and 124 can also be merged into one and include only one back pressure regulating unit 141.
[0049] As described above, when the gas discharge lines 123 and 124 are merged into one and only a back pressure regulating unit 141 is included, it has the effect that the pressure regulating unit and the line for applying pressure to the back pressure regulating unit 141 can be omitted.
[0050] The first pressure regulating unit 150 injects gas into the first and second bellows for starting the etching solution pump 120.
[0051] The gas injected through the first pressure regulating unit 150 is injected into the gas chamber of the first or second bellows of the etching solution pump 120 through the valve 130.
[0052] The control unit 210 controls the overall operation of the etching apparatus in this embodiment. Specifically, the control unit 210 controls the first pressure regulating unit 150, the second pressure regulating unit 160, and the third pressure regulating unit (…). Figure 2 (170), etching section 110, etching solution pump 120 and valve 130.
[0053] In particular, the control unit 210 controls the first pressure regulating unit 150 to apply a higher pressure (e.g., 3 bar + 2 bar) than the same pressure (e.g., 3 bar) applied to the etching unit 110 and the back pressure regulating unit 140 by the second pressure regulating unit 160.
[0054] Therefore, the control unit 210 adjusts the pressure applied to the back pressure adjustment units 140, 141, and 142 (i.e., adjusts the pressure of the back pressure adjustment units to be the same as the pressure applied to the etching unit) to prevent damage to the bellows inside the etching pump 120. In other words, by keeping the external pressure of the etching pump 120 (e.g., the pressure surrounding the bellows) the same as the internal pressure (e.g., the pressure at which the bellows is pushed by pressurized etching liquid), it has the effect of preventing bellows deformation or inner wall friction, thereby preventing bellows damage.
[0055] Figure 2 This is an example diagram illustrating a simplified configuration of the etching apparatus according to a second embodiment of the present invention. Figure 3 It is used to describe the control of the Figure 2 A flowchart illustrating the operation of the etching apparatus shown.
[0056] The above Figure 2 The second embodiment shown is the same as the one described above. Figure 1 The difference between the first embodiment shown is that an additional third pressure regulating unit 170 is added for applying pressure to the back pressure regulating unit 140.
[0057] That is, refer to Figure 2The second pressure regulating unit 160 applies pressure to the etching unit 110 only through the connected pipe 161 in order to apply pressure to the etching unit 110, without the need for a new pipe 162. The third pressure regulating unit 170 applies pressure to the back pressure regulating unit 140 through a new pipe 171 connected to the back pressure regulating unit 140, and the pressure applied to the back pressure regulating unit 140 is the same as the pressure applied to the etching unit 110.
[0058] The control unit 210 controls the third pressure regulating unit 170 to apply the same pressure (e.g., 3 bar) to the back pressure regulating unit 140 as the pressure applied to the etching unit 110 by the second pressure regulating unit 160.
[0059] In addition, the control unit 210 controls the first pressure regulating unit 150 to apply a higher pressure than that applied by the second pressure regulating unit 160 or the third pressure regulating unit 170.
[0060] Reference Figure 3 The control unit 210 detects the pressure information of the second pressure regulating unit 160 (S101). For this purpose, although not specifically shown in the figure, a pressure detection sensor (not shown) may also be included. Alternatively, the pressure information preset according to the etching process may be exported from the internal memory (not shown).
[0061] In addition, the control unit 210 adjusts the pressure of the third pressure regulating unit 170 to be the same as the pressure of the second pressure regulating unit 160 (S102).
[0062] In addition, the control unit 210 applies the pressure of the third pressure regulating unit 170 to the back pressure regulating unit 140 (S103).
[0063] Therefore, the control unit 210 adjusts the pressure applied to the back pressure regulating unit 140 to be the same as the pressure applied to the etching unit 110, thereby preventing damage to the bellows inside the etching solution pump 120. That is, by keeping the external pressure of the etching solution pump 120 (e.g., the pressure surrounding the bellows) the same as the internal pressure (e.g., the pressure at which the bellows is pushed by pressurized etching solution), it has the effect of preventing bellows deformation or inner wall friction, thereby preventing bellows damage.
[0064] On the other hand, refer to Figure 5 The etching section 110, which is composed of a pressurization system, has an etching liquid supply section 112 arranged at the lower part of the etching chamber 111. The etching liquid used for etching in the etching chamber 111 is configured to be discharged naturally to the etching liquid supply section 112 by gravity through the etching liquid discharge pipe.
[0065] However, because the diameter of the etching solution discharge pipe is small (narrow), the pressure of the etching chamber 111 and the etching solution supply section 112 is the same, so the etching solution is not easy to drain naturally.
[0066] Therefore, in this embodiment, a gas circulation pipe 191 is formed connecting the upper part of the etching solution supply unit 112 (e.g., a designated location above the position of the gas above the etching solution) to the upper part of the etching chamber 111 (e.g., a designated location above the position of the gas above the etching solution), and an air pump 190 is formed in the middle of the gas circulation pipe 191.
[0067] The gas may include air, therefore, the air pump 190 can force the movement of air, gas, or air-containing gas or process gas through the gas circulation pipe 191.
[0068] The air pump 190 forces the gas in the etching solution supply section 112 to move into the etching chamber 111 (i.e., a pressure difference is formed between the two ends of the etching solution supply section 112 and the etching chamber 111), thereby forming a gas circulation path independent of the etching solution circulation path. As described above, by using the air pump 190 to force the gas to move, in order to maintain pressure balance (i.e., to eliminate pressure difference), the etching solution and gas in the etching chamber 111 are discharged to the etching solution supply section 112 through the etching solution discharge pipe.
[0069] Figure 6 It is used to describe the control of the Figure 5 The flowchart shows the operation method of the etching apparatus. When the etching apparatus starts to drive and the etching liquid is supplied to the etching chamber 111 by the etching liquid pump 120 (S201 "Yes"), the control unit 210 drives the air pump 190 at a specified speed (S202).
[0070] Therefore, as the gas in the etching solution supply unit 112 is forced to move into the etching chamber 111, in order to maintain pressure balance, the etching solution and gas in the etching chamber 111 are discharged to the etching solution supply unit 112 through the etching solution discharge pipe. That is, even under the pressurized state of the etching unit 110, the etching solution is smoothly discharged from the etching chamber 111 to the etching solution supply unit 112.
[0071] On the other hand, if the etching apparatus stops driving or the etching liquid pump 120 stops driving, and the etching liquid is no longer supplied to the etching chamber 111 (S201 "No"), the control unit 210 immediately stops driving the air pump 190 (S203).
[0072] Therefore, the gas in the etching solution supply section 112 does not move to the etching chamber 111, and thus the etching solution and gas in the etching chamber 111 cannot be naturally discharged to the etching solution supply section 112 through the etching solution discharge pipe.
[0073] As described above, this embodiment has the following effect: even without using a discharge pump (not shown) that forces the etchant from the etching chamber 111 to the etchant supply section 112 (i.e., when a discharge pump is used, it is not easy to synchronize with the etchant pump, and problems may occur with the composition of the etching atmosphere), the etchant can be discharged smoothly and naturally to the etchant supply section 112 located at the bottom of the etching chamber 111 by gravity.
[0074] The present invention has been described above with reference to the embodiments shown in the accompanying drawings, but these are merely examples, and those skilled in the art will understand that various modifications and equivalent embodiments can be derived therefrom. Therefore, the scope of protection of the present invention should be determined according to the appended claims. Furthermore, the embodiments described in this specification can be implemented, for example, as methods or processes, apparatuses, software programs, data streams, or signals. Even if the logical description of an embodiment is presented in only one form (e.g., only as a method), the described features can be implemented in different forms (e.g., apparatuses or programs). Apparatuses can be implemented with suitable hardware, software, and firmware, etc. Methods can be implemented in devices such as processors, generally referred to as processing devices, including, for example, computers, microprocessors, integrated circuits, or programmable logic devices. Processors also include communication devices that facilitate information communication between end users, such as computers, mobile phones, portable / personal digital assistants (PDAs), and other devices.
Claims
1. An etching apparatus characterized by comprising: include: An etching chamber, wherein the etching chamber uses an etching solution to etch the object; The etching solution supply unit recovers the etching solution in the etching chamber and supplies the etching solution to the etching chamber via an etching solution pump; The first pressure regulating unit injects gas into the etching solution pump to apply driving pressure; The second pressure regulating unit pressurizes the etching chamber and the etching solution supply unit at the same specified pressure; A back pressure regulating unit adjusts the pressure of the gas discharged when the etching solution pump is driven; as well as Valves control the sequence and direction of the gas being injected into or discharged from the etching solution pump. The etching solution pump contains a bellows, and the etching solution supply unit recovers the etching solution in the etching chamber by gravity-based natural discharge.
2. The etching apparatus according to claim 1, characterized in that, The etching apparatus further includes a control unit that selectively controls one or more of the first pressure regulating unit, the second pressure regulating unit, the valve, the etching solution pump, and the back pressure regulating unit to perform etching.
3. The etching apparatus according to claim 1, characterized in that, In the second pressure regulating section, a new pipeline branching off from the pipeline connected to the etching section is connected to the back pressure regulating section, wherein the etching section includes the etching chamber and the etching solution supply section.
4. The etching apparatus according to claim 3, characterized in that, The back pressure regulating section is also subjected to the same pressure as that applied to the etching section from the second pressure regulating section through the new pipeline.
5. The etching apparatus according to claim 2, characterized in that, The control unit controls the first pressure regulating unit to apply a pressure greater than the pressure applied to the back pressure regulating unit to the etching solution pump.
6. The etching apparatus according to claim 2, characterized in that, The etching apparatus further includes a third pressure regulating unit, which independently applies pressure to the back pressure regulating unit. The control unit controls the third pressure regulating unit to apply the same pressure to the back pressure regulating unit as the pressure applied to the etching unit by the second pressure regulating unit, wherein the etching unit includes the etching chamber and the etching solution supply unit.
7. The etching apparatus according to claim 6, characterized in that, The control unit controls the first pressure regulating unit to apply a higher pressure than that applied by the second or third pressure regulating unit.
8. The etching apparatus according to claim 1, characterized in that, The gas discharge lines from the etching solution pump, which are discharged through the valve to different paths, are merged into a single gas discharge line. A back pressure regulating section is formed in one of the gas discharge lines of the confluence.
9. A method for controlling an etching apparatus, characterized in that, The etching apparatus includes: an etching chamber; an etching solution supply unit that supplies etching solution to the etching chamber via an etching solution pump; a first pressure regulating unit that injects gas into the etching solution pump to apply a driving pressure; a second pressure regulating unit that pressurizes the etching chamber and the etching solution supply unit at a specified pressure; a back pressure regulating unit that regulates the pressure of the gas discharged when the etching solution pump is driven; a valve that controls the sequence and direction of injection or discharge into the etching solution pump; and a control unit. The control method for the etching apparatus includes the following steps: The control unit selectively controls one or more of the first pressure regulating unit, the second pressure regulating unit, the valve, the etching solution pump, and the back pressure regulating unit to perform etching; and The control unit controls the first pressure regulating unit to apply a pressure greater than the pressure applied to the back pressure regulating unit to the etching solution pump. The etching solution pump contains a bellows, and the etching solution supply unit recovers the etching solution in the etching chamber by gravity-based natural discharge.
10. The control method for the etching apparatus according to claim 9, characterized in that, In the second pressure regulating section, a new pipeline branching off from the pipeline connected to the etching section is connected to the back pressure regulating section, wherein the etching section includes the etching chamber and the etching solution supply section; The control method of the etching apparatus further includes the following step: the control unit causes the same pressure as the pressure applied to the etching unit from the second pressure regulating unit to also be applied to the back pressure regulating unit.
11. The control method for the etching apparatus according to claim 9, characterized in that, The etching apparatus further includes a third pressure regulating unit, which independently applies pressure to the back pressure regulating unit; The control method of the etching apparatus further includes the following step: controlling the third pressure regulating unit so that the same pressure as the pressure applied to the etching unit by the second pressure regulating unit is applied to the back pressure regulating unit.
12. The control method for the etching apparatus according to claim 11, characterized in that, The control method of the etching apparatus further includes the following steps: the control unit controls the first pressure regulating unit to apply a higher pressure than that applied by the second pressure regulating unit or the third pressure regulating unit.