Control circuit and semiconductor process equipment

Abstract

The invention discloses a control circuit and semiconductor process equipment, and belongs to the technical field of semiconductors. The control circuit is used for controlling adsorption voltage loaded on the electrostatic chuck, and the control circuit comprises a power supply module, a current detection unit and a control unit. The power supply module is used for being connected with an adsorption electrode of the electrostatic chuck, and the current monitoring unit monitors a power supply current of the power supply module for supplying power to the adsorption electrode; the control unit is respectively connected with the power supply module and the current monitoring unit, receives a power supply current monitoring value sent by the current monitoring unit, and adjusts the current output voltage of the power supply module under the condition that the power supply current monitoring value is greater than a first current threshold value; the difference value between the adsorption voltage and a preset voltage is smaller than a preset difference value.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and specifically relates to a control circuit and a semiconductor process equipment. Background Art

[0002] The plasma wafer processing process is to transfer the wafer to be processed into the chamber wafer support table of the equipment, such as the electrostatic chuck (ESC). The electrostatic chuck has a built-in DC electrode layer. The ESC power supply provides a DC voltage to the electrode layer, thereby generating an electrostatic adsorption force between the electrode layer and the wafer, adsorbing the wafer on the electrostatic chuck.

[0003] However, during the use of the equipment, changes in related process parameters or aging of hardware will affect the stability of the DC voltage loaded on the electrostatic chuck electrode layer, affect the stability of the electrostatic chuck adsorption, cause the wafer position to move, and affect the performance of the prepared chip. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a control circuit and a semiconductor process equipment, which can achieve the stability of the DC voltage loaded on the electrostatic chuck electrode layer, ensure reliable adsorption of the wafer, and improve the performance of the prepared chip.

[0005] In order to solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, an embodiment of the present application provides a control circuit, comprising: a power supply module, a current monitoring unit and a control unit; the power supply module is used to connect to the adsorption electrode of the electrostatic chuck, and the current monitoring unit monitors the power supply current supplied by the power supply module to the adsorption electrode; the control unit is respectively connected to the power supply module and the current monitoring unit, and the control unit receives the power supply current monitoring value sent by the current monitoring unit, and when the power supply current monitoring value is greater than a first current threshold, adjusts the current output voltage of the power supply module so that the difference between the adsorption voltage and the preset voltage is less than the preset difference.

[0007] In a second aspect, an embodiment of the present application provides a semiconductor process equipment, including a process chamber and an electrostatic chuck disposed inside the process chamber, and the semiconductor process equipment also includes the control circuit as described in the first aspect.

[0008] In an embodiment of the present application, a power supply module, a current monitoring unit and a control unit are used; the power supply module is connected to the adsorption electrode of the electrostatic chuck, and the current monitoring unit monitors the power supply current supplied by the power supply module to the adsorption electrode; the control unit is respectively connected to the power supply module and the current monitoring unit, and the control unit receives the power supply current monitoring value sent by the current monitoring unit, and when the power supply current monitoring value is greater than the first current threshold, adjusts the current output voltage of the power supply module so that the difference between the adsorption voltage and the preset voltage is less than the preset difference, thereby achieving the stability of the DC voltage loaded on the electrode layer of the electrostatic chuck, ensuring reliable adsorption of the wafer, and improving the performance of the prepared chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0010] Figure 1 is a structural schematic diagram of a control circuit provided in an embodiment of the present application;

[0011] Figure 2 is an equivalent circuit diagram of a control circuit provided in an embodiment of the present application;

[0012] Figure 3 is a structural schematic diagram of another control circuit provided in an embodiment of the present application;

[0013] Figure 4 is an equivalent circuit diagram of another control circuit provided in an embodiment of the present application;

[0014] Figure 5 is a schematic flow chart of a method for controlling an adsorption voltage loaded on an electrostatic chuck provided in an embodiment of the present application;

[0015] Figure 6 It is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only 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 creative work should fall within the scope of protection of this application.

[0017] In plasma wafer processing equipment, the wafer to be processed is transferred to the chamber wafer support table of the equipment, that is, the electrostatic chuck. Electrostatic chuck (ESC) is a chuck in wafer processing equipment that uses the principle of electrostatic adsorption to fix the wafer. In addition to adsorbing the wafer, the electrostatic chuck can also control temperature, plasma energy, density and direction. The electrostatic chuck has a built-in DC electrode layer, and the ESC power supply provides a DC voltage to the electrode layer, thereby generating an electrostatic adsorption force between the electrode layer and the wafer, adsorbing the wafer on the electrostatic chuck. This process is called chuck.

[0018] To achieve reliable wafer adsorption during the process, the magnitude and stability of the DC voltage loaded on the electrostatic chuck electrode layer plays a decisive role, which determines the magnitude and stability of the electrostatic chuck adsorption force. When the equipment is in working condition, changes in process parameters or aging of hardware will affect the stability of the DC voltage, affect the stability of electrostatic chuck adsorption, cause the wafer position to move, and affect the performance of the prepared chip.

[0019] Figure 1 A schematic diagram of a control circuit provided in an embodiment of the present application is shown. Figure 1 As shown, the control circuit includes: a power module 16, a current monitoring unit 24 and a control unit 22; the power module 16 is connected to the adsorption electrode 5 of the electrostatic chuck 18, and the current monitoring unit 24 monitors the power supply current supplied by the power module 16 to the adsorption electrode 5; the control unit 22 is connected to the power module 16 and the current monitoring unit 24 respectively, and the control unit 22 receives the power supply current monitoring value sent by the current monitoring unit 24, and when the power supply current monitoring value is greater than the first current threshold, the control unit 22 adjusts the current output voltage of the power module 16 so that the difference between the adsorption voltage and the preset voltage is less than the preset difference. The preset voltage (such as V1) is set to ensure the normal adsorption performance of the electrostatic chuck, that is, the set value of the output voltage of the ESC power supply. In this embodiment, the voltage output by the ESC power supply is controlled to adjust the adsorption voltage U at both ends of the electrostatic chuck, thereby ensuring that the voltage U loaded on the adsorption electrode 5 is V1, ensuring the normal adsorption of the electrostatic chuck, and the process is executed normally.

[0020] In addition, if Figure 1 The electrostatic chuck device 18 shown, 1 is a reaction chamber, and the electrostatic chuck 18 includes an adsorption electrode layer 5, an RF electrode layer 6, a ceramic layer 7, a heating electrode 8, and a water-cooling plate 9. The cooling water circulates in the water-cooling channel of the electrostatic chuck through the water-cooling plate 9 to control the temperature of the electrostatic chuck and the wafer. In addition, the high-temperature process usually requires the heating electrode 8 to be powered by the heating power supply 11 and the filter box 10. The chamber 1 is in a vacuum state, and the heating electrode 8 transfers heat by thermal radiation. Back blowing 4 is passed under the wafer 3 to evenly heat the wafer 3 by the principle of gas heat conduction. The formal process begins after the electrostatic chuck and the wafer 3 are heated to the specified temperature.

[0021] The power module 16 includes an ESC power supply 15 and a filter box 14. The ESC power supply 15 applies a DC voltage to the electrostatic chuck electrode 5 through the filter box 14. Under the action of the electric field formed by the electrostatic chuck electrode, an electrostatic attraction is generated between the electrode 5 and the lower surface of the wafer 3, thereby fixing the wafer 3 on the upper surface of the electrostatic chuck ceramic layer 6.

[0022] At the beginning of the process, the plasma generating device is ignited in the reaction chamber to generate plasma 2. According to the process conditions, the lower electrode RF power supply 13 cooperates with the matching device 12 to generate a high-frequency magnetic field, and a plasma sheath is generated on the upper surface of the wafer 3. The voltage difference (DC self-bias) between the sheath and the wafer 3 forms an electric field, which attracts various charged particles in the plasma 2 to process the surface of the wafer 3.

[0023] In one embodiment of the present application, the control unit includes a PLC communication module, and the lower computer 17 controls the ESC power supply 15 through the PLC communication module, wherein signal interaction can be performed between the lower computer 17 and the PLC communication module and between the ESC power supply 15 and the PLC communication module through different protocols.

[0024] In one embodiment of the present application, the control unit 22 can also control the communication and data collection functions between the PLC communication module and the ESC power supply and the lower computer 17, such as real-time collection of ESC power supply data.

[0025] Figure 2 An equivalent circuit diagram of a control circuit provided in an embodiment of the present application is shown. Figure 2The lower surface of the middle wafer 3 and the electrostatic chuck electrode 5 are electrically insulated from each other, which is equivalent to the parallel connection of capacitor C18 and resistor R2 19. Generally, because the ceramic layer 5 is a high insulating material, R2 is ∞. R1 20 is the internal resistance of the control circuit, which generally includes the internal resistance of the ESC power supply, the resistance of the filter box, and the resistance of the cables connected to each other. The loop current of the electrostatic chuck system I=V1 / (R1+R2). Because R2 is ∞, the voltage U≈V1 loaded on the chuck electrode 5. The electrostatic attraction F∝U, the larger U is, the larger F is, the more reliable the wafer adsorption is, and it does not move or jump during the process.

[0026] In actual application, due to the aging of the equipment, the ceramic material slowly polarizes, causing the resistivity of the electrostatic chuck to change, especially in the thin film deposition process, the conductive material is inevitably deposited on the surface of the electrostatic chuck ceramic layer 7, reducing the resistivity of the ceramic layer 5, causing R2 to become smaller. Depending on the process parameters, R2 often changes continuously during the process. In addition, there may be sudden abnormalities, resulting in a local short circuit in the ESC electrical circuit of the electrostatic chuck system and a huge change in the current I. The change in current I will cause the equivalent voltage across the R1 resistor 20 to increase, causing the voltage U across the chuck to be less than the set voltage V1. The change is recorded as ΔU, then:

[0027] U=V1-ΔU (1)

[0028]

[0029] Among them: R2 is the only variable.

[0030] And when ΔU reaches a certain size, such as the preset difference, and significantly reduces the size of the voltage U loaded on the DC electrode, it will affect the stability of the electrostatic chuck adsorption, causing the wafer position to move. The entire process line will undergo different process steps in different chambers. If the wafer position moves in any chamber, it will directly affect the chip performance and yield of the wafer preparation on the assembly line.

[0031] In one implementation, the control unit 22 is used to determine whether the power supply current I exceeds the default set current limit value I1 of the ESC power supply, that is, the first current threshold. If the current I exceeds the set current limit value I1, the host computer software alarms and controls the current output voltage of the power module to be adjusted so that the difference between the adsorption voltage and the preset voltage is less than the preset difference. Among them, the set current limit value I1 can be calculated by the normal current I of the control circuit and the deviation voltage allowed by the software. Specifically, the first current threshold can be determined according to the ratio of the preset difference and the internal resistance of the control circuit.

[0032] Specifically, assuming that the set voltage is V1 and the normal operating current is I, the electrostatic chuck resistance R2 is calculated as:

[0033]

[0034] Then the voltage U across the electrostatic chuck is:

[0035]

[0036] If the software allows a deviation voltage of V2 (i.e., a preset deviation voltage), and the minimum allowable resistance of the electrostatic chuck is x, then the set current limit value I1 is calculated as follows:

[0037]

[0038] but

[0039]

[0040] so

[0041]

[0042] The control circuit provided in the embodiment of the present application includes a power supply module, a current monitoring unit and a control unit; the power supply module is connected to the adsorption electrode of the electrostatic chuck, and the current monitoring unit monitors the power supply current supplied by the power supply module to the adsorption electrode; the control unit is respectively connected to the power supply module and the current monitoring unit, and the control unit receives the power supply current monitoring value sent by the current monitoring unit, and when the power supply current monitoring value is greater than the first current threshold, adjusts the current output voltage of the power supply module so that the difference between the adsorption voltage and the preset voltage is less than the preset difference, thereby achieving the stability of the DC voltage loaded on the electrode layer of the electrostatic chuck, ensuring reliable adsorption of the wafer, and improving the performance of the prepared chip.

[0043] In one implementation, the output voltage of the current power module is adjusted so that the difference between the adsorption voltage and the preset voltage is less than the preset difference, including: determining a compensation voltage based on the supply current monitoring value, the internal resistance of the control circuit and the preset voltage; and controlling the power module to increase the output voltage based on the compensation voltage so that the difference between the adsorption voltage and the preset voltage is less than the preset difference.

[0044] In one implementation, determining the compensation voltage according to the power supply current monitoring value, the internal resistance of the control circuit and the preset voltage includes:

[0045] The compensation voltage is determined according to the following formula:

[0046]

[0047] Among them, V1 is the preset voltage, I β is the power supply current monitoring value, R1 is the internal resistance of the control circuit, and V′ is the compensation voltage.

[0048] Specifically, under normal conditions, the resistance R2 of the electrostatic chuck device is ∞, and at this time, the power supply current monitoring value I β satisfy:

[0049]

[0050] When the resistance at both ends of the electrostatic chuck changes to R3, the current I increases and becomes:

[0051]

[0052] Assuming that there is a deviation ΔU between the preset voltage V1 and the actual voltage U at both ends of the chuck, if ΔU=|U-V1|≤V2, the process is performed normally, where V2 is the preset difference. The current increases, causing the actual voltage U at both ends of the chuck to decrease. The embodiment of the present application determines the compensation voltage V′ based on the power supply current monitoring value, the internal resistance of the control circuit and the preset voltage, and resets the ESC power supply output voltage to V+V′, thereby ensuring that the voltage U loaded on the chuck electrode 5 ≈ V1, that is, ensuring that the voltage U loaded on the chuck electrode 5 satisfies, ΔU=|U-V1|≤V2, where the compensation voltage V′ is:

[0053]

[0054] According to the above formulas (9) and (10), we can get

[0055]

[0056] After the compensation voltage is determined, it can be fed back to the lower computer 17 through the aforementioned PLC communication module, and after resetting the ESC power supply output voltage to V+V', the software logic judgment process is entered to judge the current value I. In the embodiment of the present application, the entire software compensation time period is t2, and the current sampling period of the current monitoring unit is t1, t1>t2. After the compensation is completed, the voltage U≈V1 loaded on the chuck electrode 5 is satisfied, and the software enters the control logic process again to execute the process normally.

[0057] In another case, if the electrical circuit in the control circuit is partially short-circuited, the circuit current I will change drastically. The ESC power supply will drop the voltage sharply to prevent the power supply from burning out. The continuous back-blowing under the wafer will also cause the wafer to move. If the back-blowing force is too strong and the wafer is blown away, there will be a risk of fragments and the electrostatic chuck being plated with materials. If the wafer is broken, it is necessary to open the cavity to remove the fragments. If the chuck is plated with materials, it is necessary to return the electrostatic chuck to the factory for cleaning or replacement, which not only seriously affects the progress of the production line process, but also causes unnecessary costs.

[0058] Figure 3 FIG. 4 shows a schematic diagram of another control circuit provided in an embodiment of the present application. Figure 3 As shown, the control circuit includes: a power module 16, a current monitoring unit 24 and a control unit 22; the power module 16 is connected to the adsorption electrode 5 of the electrostatic chuck 18, and the current monitoring unit 24 monitors the power supply current supplied by the power module 16 to the adsorption electrode 5; the control unit 22 is respectively connected to the power module 16 and the current monitoring unit 24, and the control unit 22 receives the power supply current monitoring value sent by the current monitoring unit 24; the control circuit also includes a variable resistor 23, a first fixed end of the variable resistor 23 is connected to the adsorption electrode 5, and a second fixed end of the variable resistor is connected to the power module 16; the control unit 22 is also used to adjust the mobile end of the variable resistor 23 when the power supply current monitoring value is greater than or equal to a second current threshold, so that the power supply current monitoring value is less than the second current threshold, wherein the second current threshold can be set based on the default limit current value a set in the ESC power supply, and the second current threshold is greater than the first current threshold.

[0059] Optionally, the variable resistor 23 can be a digital potentiometer. When the current I is too large, the resistance of the digital potentiometer is adjusted to reduce the chuck high voltage and stabilize the chuck voltage within the normal current range, thereby realizing the short-circuit protection function for the chuck device. At the same time, it also ensures that the wafer is not completely blown away due to voltage fluctuations or excessively low voltage.

[0060] like Figure 4The equivalent circuit diagram of another control circuit provided by the embodiment of the present application is shown. A digital potentiometer 22 is connected in series in the ESC circuit. The resistance R' of the digital potentiometer 22 is 0 in the initial state. When the software logic determines that the current current Iβ exceeds the second current threshold I2, a short circuit occurs in the circuit, and the voltage across the chuck drops to 0V, triggering the control unit 22 to change the resistance R' of the potentiometer. When the resistance R' increases, there will be no short circuit in the circuit, and the voltage across the chuck is restored from the short-circuit state of 0V to the normal state, and the voltage increases. However, since R' divides a part of the voltage, the voltage across the chuck is less than the original set value, and the chuck is restored to the non-short-circuited state.

[0061] In one implementation, the control unit is further used to adjust the mobile end of the variable resistor when the power supply current monitoring value is greater than or equal to a second current threshold so that the power supply current monitoring value is less than the second current threshold, including: determining the target resistance value of the variable resistor based on the preset voltage, the preset voltage division coefficient and the power supply current monitoring value before adjusting the mobile end of the variable resistor; and adjusting the mobile end of the variable resistor based on the target resistance value so that the resistance value of the variable resistor increases to the target resistance value.

[0062] In one implementation, determining the target resistance of the variable resistor according to the preset voltage, the preset voltage division coefficient, and the power supply current monitoring value before adjusting the mobile end of the variable resistor includes:

[0063] The target resistance of the variable resistor is determined according to the following formula:

[0064]

[0065] in, is the preset voltage division coefficient and V1 is the preset voltage, I β is the power supply current monitoring value.

[0066] Specifically, see Figure 4 The equivalent circuit diagram shown in the figure shows that the change in the digital potentiometer resistance is related to the voltage division coefficient set by the software. Ensure that the voltage across the electrostatic chuck is therefore:

[0067]

[0068] Where: R' represents the variable resistor, represents the voltage division coefficient of the variable resistor, V1 represents the set voltage value, and R2 represents the resistance 19 of the electrostatic chuck device 18. Combining formula (12) and the aforementioned formula (8) β≈V1 / R2, the target resistance of the digital potentiometer 23 is calculated as:

[0069]

[0070] In one implementation, the control unit is also used to determine whether the power supply current monitoring value is greater than or equal to the second current threshold after controlling the resistance of the variable resistor to increase to the target resistance. If so, reduce the preset voltage division coefficient and increase the resistance of the variable resistor to the next target resistance until the power supply current monitoring value is less than the second current threshold. If not, turn off the power supply module and send a short circuit alarm signal.

[0071] In one implementation, the preset voltage division coefficient Wherein, n is a positive integer, b<1; reducing the preset voltage division coefficient and increasing the resistance value of the variable resistor to the next target resistance value includes increasing n by 1 to reduce the preset voltage division coefficient.

[0072] Specifically, in the embodiment of the present application, the voltage division coefficient can be set for the first time Where n is a positive integer, b<1; adjust the digital potentiometer 23 to change the resistance R', and then enter the process again to determine the collected current value I and the limit current value I2. If the chuck short circuit phenomenon disappears, that is, I<I2, then directly enter the alarm state; if the short circuit phenomenon I≥I2 still exists, change the coefficient n, set n=n+1, and enter the short circuit protection mode again, until the chuck short circuit phenomenon disappears, that is, I<I2, but there is still an adsorption voltage at both ends of the electrostatic chuck to prevent wafer flying.

[0073] After the power supply current monitoring value is less than the second current threshold, that is, after the short circuit problem in the loop is eliminated, the software automatically stops the process, stops back blowing, turns off the heater, turns off the ESC DC power supply, and the host computer alarms.

[0074] In one implementation, the voltage across the electrostatic chuck does not short-circuit when it is 1700V, but short-circuit occurs after 1800V. It can be set to 0.9 to ensure that the voltage at both ends of the chuck disk drops, get rid of the short circuit problem, and still have a large adsorption force. If in actual use, the first setting is 0.9, and the short circuit phenomenon still occurs after adjusting the voltage according to the process, the next time n=2 is used, and the second Enter the voltage adjustment mode again until there is no short circuit problem in the circuit.

[0075] Therefore, 0.9 is set for the first time in order to make the adjusted voltage as close as possible to the set voltage V1, to ensure the condition of maximum adsorption force and to eliminate the short circuit problem in the loop.

[0076] In one implementation, if the monitored power supply current value is not greater than the first current threshold, that is, I ≤ I1 < I2, it indicates that the voltage deviation across the electrostatic chuck is within the controllable range, and there is no need to adjust the voltage. The process can be executed normally.

[0077] Figure 5 FIG. 4 shows a schematic flowchart of a method for controlling the adsorption voltage applied to an electrostatic chuck provided by an embodiment of the present application. This method can be executed by an electronic device, such as a terminal device or a server device. In other words, the method can be executed by software or hardware installed in the terminal device or the server device. As Figure 5 shown, the method may include the following steps:

[0078] S501: Execute the process, and the ESC power supply outputs voltage V1.

[0079] S502: Collect the actual current value I.

[0080] In this step, the current monitoring unit 24 is used to collect in real time the power supply current supplied by the power supply module 16 to the electrostatic chuck 18, and obtain the monitored power supply current value I.

[0081] In one implementation, the ESC power supply internally has voltage detection and current detection devices, which are sensors integrated on a Printed Circuit Board (PCB). They can detect the loop current and the actual output voltage V of the ESC power supply, and then transmit them to the lower computer 17 through the PLC communication module 16.

[0082] S503: Determine whether I ≥ I2 holds.

[0083] In this step, it is determined whether the power supply current I supplied by the power supply module to the electrostatic chuck is greater than the second current threshold I2.

[0084] If I ≥ I2 holds, it indicates that a short circuit has occurred inside the electrostatic chuck loop. Control the electrostatic chuck device to enter the short-circuit protection mode, and execute steps S5041 to S5046; if I ≥ I2 does not hold, continue to determine whether I < I1 holds, that is, execute step S5051.

[0085] S5041: Short-circuit protection mode.

[0086] S5042: Determine the voltage division coefficient b n .

[0087] In this step, the voltage division coefficient can be set to b n , where n = 1 and b < 1.

[0088] S5043: Calculate the target resistance value of the variable resistor.

[0089] In this step, the target resistance value of the variable resistor can be determined according to the preset voltage, the preset voltage division coefficient, and the internal resistance of the control circuit.

[0090] S5044: Adjust the movable end of the variable resistor according to R'.

[0091] In this step, according to the resistance value R' of the variable resistor calculated in the previous step, the movable end of the variable resistor is adjusted to the target resistance value.

[0092] S5045: Determine whether I < I1 holds.

[0093] If I < I1 does not hold, then set n = n + 1 to decrease the preset voltage division coefficient, increase the resistance value of the variable resistor to the next target resistance value, and loop to execute step S5045 until the monitored power supply current value is less than the second current threshold.

[0094] S5046: Stop the process, turn off the ESC DC power supply, and alarm.

[0095] That is, when the short - circuit phenomenon of the electrostatic chuck disappears, stop the back - blowing, turn off the heater Heater, turn off the ESC DC power supply, and the host computer alarms, and the process ends.

[0096] Thus, by adjusting the resistance value of the variable resistor, when the resistance of R' becomes larger, there will be no short - circuit situation in the circuit. The voltage division at both ends of the chuck returns from 0V in the short - circuit state to the normal state, and the voltage increases. Since R' divides part of the voltage, the voltage at both ends of the chuck is less than the original set value, and the chuck returns to the non - short - circuit state. At the same time, there is still an adsorption voltage at both ends of the electrostatic chuck to prevent faults such as wafer flying.

[0097] S5051: Determine whether I < I1 holds.

[0098] If I < I1 holds, then execute step S5052a, that is, normally execute the process flow.

[0099] If I < I1 does not hold, that is, I ≥ I1, then enter the voltage compensation mode and execute steps S5052b - S5054.

[0100] Specifically, the resistance at both ends of the electrostatic chuck changes, resulting in an increase in the current I. It is necessary to compensate the voltage at both ends of the electrostatic chuck so that the difference between the voltage at both ends of the electrostatic chuck and the preset voltage is less than the preset difference, thereby keeping the voltage U ≈ V1 applied to the electrode 5 of the electrostatic chuck.

[0101] S5053: Calculate the compensation voltage V'.

[0102] In this step, the compensation voltage V' can be determined according to the power supply current monitoring value, the internal resistance of the control circuit and the preset voltage.

[0103] S5054: ESC DC voltage changes to set voltage (V+V').

[0104] Therefore, by judging the loop current I of the electrostatic chuck system and the size of the set current limiting value I1 (first current threshold) and the limiting current value I2 (second current threshold), the automatic control software performs voltage compensation or short-circuit protection, accurately controls the consistency of the voltage at both ends of the chuck with the set voltage, ensures the stability of the chuck voltage and current during the wafer preparation process, and improves the reliability of the system operation.

[0105] It should be noted that the method for controlling the adsorption voltage loaded on the electrostatic chuck provided in the embodiment of the present application can be executed by the control circuit described in the aforementioned embodiment, or a control unit in the control circuit.

[0106] Another embodiment of the present application provides a semiconductor process equipment, including a process chamber and an electrostatic chuck disposed inside the process chamber, and the semiconductor process equipment also includes a control circuit as described in any of the aforementioned embodiments.

[0107] Figure 6 A schematic diagram of the hardware structure of an electronic device that implements the embodiment of the present application is shown. Referring to the figure, at the hardware level, the electronic device includes a processor, and optionally, an internal bus, a network interface, and a memory. Among them, the memory may include a memory, such as a high-speed random access memory (Random-Access Memory, RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage, etc. Of course, the electronic device may also include hardware required for other services.

[0108] The processor, the network interface and the memory may be interconnected through an internal bus, which may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one bidirectional arrow is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0109] The memory is used to store the program. Specifically, the program may include a program code, and the program code includes a computer operation instruction. The memory may include a memory and a non-volatile memory, and provides instructions and data to the processor.

[0110] The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it, forming a device for locating the target user at the logical level. The processor executes the program stored in the memory and is specifically used to execute: each step of the method for controlling the adsorption voltage loaded on the electrostatic chuck.

[0111] The methods disclosed in the embodiments shown in the flowcharts of the present application can be applied to a processor or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiments of the present application can be directly embodied as a hardware decoding processor for execution, or a combination of hardware and software modules in the decoding processor for execution. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0112] The electronic device can also execute the method of controlling the adsorption voltage loaded on the electrostatic chuck described in the aforementioned embodiment, and can achieve the same technical effect as the embodiment of the method, which will not be repeated here.

[0113] Of course, in addition to software implementation methods, the electronic device of the present application does not exclude other implementation methods, such as logic devices or a combination of software and hardware, etc. That is to say, the execution subject of the following processing flow is not limited to each logic unit, but can also be hardware or logic devices.

[0114] An embodiment of the present application also proposes a computer-readable storage medium, which stores one or more programs. When the one or more programs are executed by an electronic device including multiple application programs, the electronic device executes the various steps of the method for controlling the adsorption voltage loaded on the electrostatic chuck described in the above embodiment.

[0115] The computer-readable storage medium includes a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0116] Furthermore, an embodiment of the present application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the various steps in the above method embodiment are implemented.

[0117] In short, the above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0118] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0119] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0120] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0121] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

Claims

1. A control circuit for controlling the adsorption voltage loaded on an electrostatic chuck, characterized in that: The control circuit includes a power supply module, a current monitoring unit and a control unit; The power module is connected to the adsorption electrode of the electrostatic chuck, and the current monitoring unit monitors the power supply current supplied by the power module to the adsorption electrode; The control unit is connected to the power module and the current monitoring unit respectively, and the control unit receives a power supply current monitoring value sent by the current monitoring unit, and when the power supply current monitoring value is greater than a first current threshold, adjusts the current output voltage of the power module so that the difference between the adsorption voltage and the preset voltage is less than the preset difference.

2. The control circuit according to claim 1, characterized in that: The step of adjusting the current output voltage of the power module so that the difference between the adsorption voltage and the preset voltage is less than the preset difference includes: Determining a compensation voltage according to the power supply current monitoring value, the internal resistance of the control circuit and the preset voltage; According to the compensation voltage, the power module is controlled to increase the output voltage so that the difference between the adsorption voltage and the preset voltage is smaller than the preset difference.

3. The control circuit according to claim 2, characterized in that: The determining of the compensation voltage according to the power supply current monitoring value, the internal resistance of the control circuit and the preset voltage includes: The compensation voltage is determined according to the following formula: Among them, V1 is the preset voltage, I β is the power supply current monitoring value, R1 is the internal resistance of the control circuit, and V′ is the compensation voltage.

4. The control circuit according to claim 1, characterized in that: The control unit is further configured to determine the first current threshold value according to a ratio of the preset difference and an internal resistance of the control circuit.

5. The control circuit according to claim 1, characterized in that: The control circuit further comprises a variable resistor, a first fixed end of the variable resistor is connected to the adsorption electrode, and a second fixed end of the variable resistor is connected to the power module; The control unit is also used to adjust the movable end of the variable resistor when the power supply current monitoring value is greater than or equal to a second current threshold, so that the power supply current monitoring value is less than the second current threshold, wherein the second current threshold is greater than the first current threshold.

6. The control circuit according to claim 5, characterized in that: The control unit is further configured to adjust the movable end of the variable resistor when the power supply current monitoring value is greater than or equal to a second current threshold value, so that the power supply current monitoring value is less than the second current threshold value, including: Determining a target resistance value of the variable resistor according to the preset voltage, the preset voltage division coefficient and the supply current monitoring value; According to the target resistance value, the movable end of the variable resistor is adjusted to increase the resistance value of the variable resistor to the target resistance value.

7. The control circuit according to claim 6, characterized in that: The step of determining a target resistance value of the variable resistor according to the preset voltage, the preset voltage division coefficient and the power supply current monitoring value comprises: The target resistance of the variable resistor is determined according to the following formula: in, is the preset voltage division coefficient and V1 is the preset voltage, I β is the power supply current monitoring value, and R′ is the target resistance value of the variable resistor.

8. The control circuit according to claim 6, characterized in that: The control unit is also used to determine whether the power supply current monitoring value is greater than or equal to the second current threshold after controlling the resistance of the variable resistor to increase to the target resistance. If so, reduce the preset voltage division coefficient and increase the resistance of the variable resistor to the next target resistance until the power supply current monitoring value is less than the second current threshold. If not, turn off the power supply module and send a short circuit alarm signal.

9. The control circuit according to claim 8, characterized in that: The preset voltage division coefficient Where n is a positive integer, b<1; The reducing the preset voltage division coefficient and increasing the resistance value of the variable resistor to the next target resistance value includes increasing n by 1 to reduce the preset voltage division coefficient.

10. A semiconductor process equipment, comprising a process chamber and an electrostatic chuck arranged inside the process chamber, the semiconductor process equipment further comprising a control circuit as claimed in any one of claims 1 to 9.

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