Pressure control method and semiconductor process equipment

Abstract

The invention provides a pressure control method and semiconductor process equipment, and the method comprises the steps: obtaining a supporting force provided for a wafer by an electrostatic chuck when the wafer is located on the electrostatic chuck; judging whether the supporting force is within a theoretical supporting force range; wherein the theoretical supporting force range is preset according to the weight of the wafer; if the supporting force is not within the theoretical supporting force range, the heating medium gas is controlled to execute pressure regulating operation, so that the pressure is increased or decreased from the current value; and updating the current value after executing the pressure regulation operation, and returning to execute the step of obtaining the supporting force until the supporting force is within the theoretical supporting force range. By adopting the pressure control method, the pressure applied to the wafer by the heating medium gas is not a constant value and can be automatically adjusted, so that the wafer can be kept in a good adsorption state, the risk of wafer fragmentation is reduced, the process does not need to be terminated, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a pressure control method and semiconductor process equipment. Background Art

[0002] An electrostatic chuck (ESC) is installed in the chamber of the semiconductor process equipment. The electrostatic chuck is used to carry the wafer. An electrode is installed inside the electrostatic chuck. The electrode is electrically connected to a DC power supply. The free electrons inside the wafer move in a directed manner to form an induced charge. The polarity of the induced charge is opposite to the polarity of the charge of the electrode, and an electrostatic attraction is generated between the two, thereby adsorbing the wafer on the top surface of the electrostatic chuck.

[0003] The electrostatic chuck is provided with an air flow channel, the air inlet of the air flow channel is connected to the air inlet device, and the air outlet of the air flow channel is located on the top surface of the electrostatic chuck. The air inlet device can blow a constant pressure of hot medium gas to the back of the wafer through the air flow channel. In this way, the temperature of the wafer can be adjusted, and secondly, after the process is completed, when the wafer is released, the hot medium gas will exert a certain pressure on the wafer to offset or even eliminate the electrostatic attraction caused by the residual induced charge on the wafer.

[0004] At present, most semiconductor process equipment, such as CCP (Capacitively Coupled Plasma) dielectric etcher, is prone to wafer breakage during the process. At this time, the process needs to be terminated and the semiconductor process equipment needs to be restored to normal through manual intervention, resulting in low production efficiency. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a pressure control method and semiconductor process equipment.

[0006] In order to achieve the purpose of the present invention, a pressure control method is provided to control the pressure applied by the heat medium gas to the wafer. The pressure control method comprises:

[0007] When the wafer is on the electrostatic chuck, obtaining a supporting force provided by the electrostatic chuck for the wafer;

[0008] Determining whether the supporting force is within a theoretical supporting force range; wherein the theoretical supporting force range is pre-set according to the weight of the wafer;

[0009] If the supporting force is not within the theoretical supporting force range, controlling the heat medium gas to perform a pressure adjustment operation so that the pressure increases or decreases from a current value;

[0010] After performing the pressure adjustment operation, the current value is updated, and the step of obtaining the supporting force is returned to be executed until the supporting force is within the theoretical supporting force range.

[0011] The pressure control method as described above, wherein if the support force is not within the theoretical support force range, controlling the heat medium gas to perform a pressure adjustment operation so that the pressure increases or decreases from the current value, specifically includes:

[0012] If the supporting force is not within the theoretical supporting force range, comparing the supporting force with any one of a lower limit value and an upper limit value of the theoretical supporting force range to obtain a comparison result;

[0013] When the comparison result shows that the supporting force is greater than the upper limit value, determining that the pressure regulating operation is a pressure increasing operation, so that the pressure increases from the current value;

[0014] When the comparison result is that the supporting force is less than the lower limit value, the pressure regulating operation is determined to be a pressure reducing operation, so that the pressure is reduced from the current value.

[0015] The pressure control method as described above, wherein when the comparison result is that the supporting force is less than the lower limit value, determining that the pressure regulating operation is a pressure reducing operation so as to reduce the pressure from the current value, specifically includes:

[0016] When the comparison result is that the supporting force is less than the lower limit value, determining whether the supporting force satisfies a first preset condition and a second preset condition; wherein the first preset condition is that the supporting force is 0, and the second preset condition is that the supporting force is 0 for the first time;

[0017] When the supporting force does not satisfy at least one of the first preset condition and the second preset condition, the pressure regulating operation is determined to be a pressure reducing operation, so that the pressure is reduced from a current value.

[0018] In the pressure control method as described above, when the supporting force does not meet the first preset condition, when the pressure reduction operation is performed, the change in the pressure is negatively correlated with the number of executions of the pressure reduction operation; and each time the pressure reduction operation is performed, the number of executions of the pressure reduction operation is correspondingly updated;

[0019] When the boost operation is performed, the change in the pressure is negatively correlated with the number of times the boost operation is performed; and each time the boost operation is performed, the number of times the boost operation is performed is correspondingly updated.

[0020] The pressure control method as described above, wherein, when the pressure reduction operation is performed, the change in pressure is equal to the ratio of the second set increment to the number of executions of the pressure reduction operation;

[0021] When the pressure boosting operation is performed, the change in pressure is equal to the ratio of the second set increment to the number of times the pressure boosting operation is performed.

[0022] The pressure control method as described above, wherein the initial values ​​of the number of executions of the pressure reduction operation and the number of executions of the pressure boost operation are 0; before executing the pressure reduction operation, the number of executions of the pressure reduction operation is updated; before executing the pressure boost operation, the number of executions of the pressure boost operation is updated; or,

[0023] The initial values ​​of the number of executions of the step-down operation and the number of executions of the step-up operation are 1; after the step-down operation is performed, the number of executions of the step-down operation is updated; after the step-up operation is performed, the number of executions of the step-up operation is updated.

[0024] The pressure control method as described above, wherein, after determining whether the supporting force is within the theoretical supporting force range, further comprises:

[0025] If the supporting force is within the theoretical supporting force range, the number of executions of the pressure reduction operation and the number of executions of the pressure increase operation are reset to initial values.

[0026] In the pressure control method as described above, when the supporting force satisfies the first preset condition and does not satisfy the second preset condition, when the pressure reduction operation is performed, the change amount of the pressure is a first set increment.

[0027] The pressure control method as described above, wherein, when the comparison result is that the supporting force is less than the lower limit value, after determining whether the supporting force satisfies the first preset condition and the second preset condition, further comprises:

[0028] When the supporting force satisfies the first preset condition and the second preset condition, a critical pressure value is calculated according to the weight and the adsorption voltage value on the electrostatic chuck, the critical pressure value is assigned to the current value, and the step of obtaining the supporting force is returned.

[0029] In the pressure control method as described above, the step of obtaining the supporting force provided by the electrostatic chuck for the wafer specifically includes:

[0030] Obtaining component forces respectively provided by a plurality of support columns arranged on the electrostatic chuck to the wafer, and determining the supporting force according to the component forces;

[0031] Before determining whether the supporting force is within the theoretical supporting force range, the method further includes:

[0032] Determine whether the difference between the component forces corresponding to every two of the support columns is less than a target threshold; wherein the target threshold is a ratio of the weight to a characteristic value, and the characteristic value is equal to the number of the support columns minus 1;

[0033] If not, an alarm message is issued, wherein the alarm message is used to indicate that the adsorption state of the wafer is abnormal.

[0034] The pressure control method as described above, wherein the timing is started when the wafer is located on the electrostatic chuck;

[0035] Before returning to execute the step of obtaining the supporting force, the method further includes:

[0036] Determine whether the timing time exceeds the preset time;

[0037] If so, an alarm message is issued, wherein the alarm message is used to indicate that the adsorption state of the wafer is abnormal.

[0038] The pressure control method as described above, wherein, after determining whether the supporting force is within the theoretical supporting force range, further comprises:

[0039] If the supporting force is within the theoretical supporting force range, the timing time is cleared to 0.

[0040] The pressure control method as described above, wherein, after determining whether the supporting force is within the theoretical supporting force range, further comprises:

[0041] If the supporting force is within the theoretical supporting force range, obtaining the temperature of the heat medium gas between the wafer and the electrostatic chuck;

[0042] When the temperature does not meet a preset threshold, a temperature control device for adjusting the temperature of the electrostatic chuck is controlled to adjust the temperature of the heat medium gas.

[0043] As another technical solution, the present invention also provides a semiconductor process equipment, including: a chamber, an electrostatic chuck, a voltage detection device, a pressure detection device and a controller;

[0044] An electrostatic chuck is disposed in the chamber and is used to carry the wafer. An air flow channel is provided on the electrostatic chuck. The air inlet of the air flow channel is used to communicate with an air inlet device located outside the chamber. The air outlet of the air flow channel is located on the top surface of the electrostatic chuck. The air inlet device is used to introduce heat medium gas to the back of the wafer.

[0045] The voltage detection device is used to detect the adsorption voltage value on the electrostatic chuck;

[0046] The pressure detection device is used to detect the supporting force provided by the electrostatic chuck to the wafer;

[0047] The controller is electrically connected to the air intake device, the voltage detection device and the pressure detection device. The controller includes at least one processor and at least one memory. The memory stores a computer program. The processor executes the computer program to execute the pressure control method provided in any embodiment of the present invention.

[0048] The semiconductor process equipment as described above, wherein the semiconductor process equipment further comprises a temperature detection device electrically connected to the controller, wherein the temperature detection device is used to detect the temperature of the heat medium gas between the wafer and the top surface of the electrostatic chuck.

[0049] The semiconductor process equipment as described above, wherein the semiconductor process equipment also includes a plurality of support pillars erected on the top surface of the electrostatic chuck, and the wafer is placed on the support pillars; a plurality of pressure detection devices are provided, and the plurality of pressure detection devices are arranged one by one at the top ends of the plurality of support pillars.

[0050] The present invention has the following beneficial effects:

[0051] The pressure control method and semiconductor process equipment provided by the embodiments of the present invention obtain the supporting force of the electrostatic chuck on the wafer and judge whether the supporting force is within the theoretical supporting force range. According to the judgment result, it can be known whether there is an abnormality in the adsorption state of the wafer. When the supporting force exceeds the theoretical supporting force range, the pressure is adjusted by controlling the heat medium gas. In this embodiment, the gravity and electrostatic attraction of the wafer remain unchanged, so when the pressure changes, the supporting force can change accordingly. In this way, by regulating the pressure, the supporting force is within the theoretical supporting force range, and the wafer can be in a good adsorption state in the subsequent process.

[0052] Therefore, using the pressure control method of this embodiment, the pressure applied by the heat medium gas to the wafer is not a constant value, but can be automatically adjusted. In this way, when the DC power supply of the semiconductor process equipment fails and the electrostatic attraction is too small, the force on the wafer can still be kept balanced by adjusting the pressure, and the wafer can be stably adsorbed on the electrostatic chuck to reduce the risk of the wafer being blown away and hitting the cavity to cause fragments. When a large amount of newly generated negative charges accumulate on the electrostatic chuck during the process, causing the wafer to be unable to be completely desorbed, the pressure can be adjusted so that the wafer can be stably adsorbed on the electrostatic chuck, and the risk of the wafer being hit by the lifting needle and broken can be reduced. In general, there is no need to shut down the semiconductor process equipment for maintenance, which saves unnecessary process terminations, improves production efficiency, and reduces the generation of defective products. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A schematic diagram of the structure of a semiconductor process equipment provided in an embodiment of the present application;

[0054] Figure 2 for Figure 1 Schematic diagram of force analysis of the wafer shown;

[0055] Figure 3 A schematic diagram of a hardware module of a semiconductor process equipment provided in an embodiment of the present application;

[0056] Figure 4 A schematic flow chart of a pressure control method provided in an embodiment of the present application;

[0057] Figure 5 A schematic diagram of the structure of another semiconductor process equipment provided in an embodiment of the present application;

[0058] Figure 6 for Figure 5 A schematic diagram showing the relationship between an electrostatic chuck and a plurality of support pillars in a semiconductor process equipment shown;

[0059] Figure 7 A flow chart of another pressure control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0060] The following embodiments of the present application provide a semiconductor process equipment, wherein a chamber of the semiconductor process equipment is as follows: Figure 1 As shown, the process that can be implemented in the chamber 110 includes but is not limited to the etching process. Figure 1 A schematic structural diagram of a semiconductor process equipment 1000 provided in an embodiment of the present application is shown.

[0061] See also Figure 1 An electrostatic chuck 111 for carrying the wafer 2000 is provided in the chamber 110, and a radio frequency source 112 is provided on the top of the chamber 110. The radio frequency source 112 is used to provide a radio frequency signal to generate a magnetic field in the chamber 110 to excite the process gas in the chamber 110 into plasma. The plasma reacts with the surface of the wafer 2000 to achieve etching.

[0062] An air flow channel 1110 is provided inside the electrostatic chuck 111. The air inlet of the air flow channel 1110 is used to be connected to the air inlet device 130 located outside the chamber 110. The air outlet of the air flow channel 1110 is located on the top surface of the electrostatic chuck 111 to blow hot medium gas to the back side of the wafer 2000 to heat the wafer 2000.

[0063] In the semiconductor process equipment 1000 disclosed herein, specific methods for heating the wafer 2000 include but are not limited to the following possibilities.

[0064] In one possible manner, the temperature of the heat medium gas is controllable. For example, the air inlet device 130 can directly provide high-temperature heat medium gas so that the wafer 2000 can be heated to a target temperature. For another example, the semiconductor process equipment 1000 includes a heating device, which is used to heat the heat medium gas so that the heat medium gas can reach a target temperature.

[0065] In another possible embodiment, a heater 210 is provided inside the electrostatic chuck 111. The heater 210 is connected to a power source. When the heater 210 is powered on, it generates heat, so that the electrostatic chuck 111 is heated. The heat medium gas flowing into the gap between the top surface of the electrostatic chuck 111 and the back surface of the wafer 2000 serves as a heat transfer medium. The heat medium gas can evenly transfer the heat of the electrostatic chuck 111 to the wafer 2000, thereby heating the wafer 2000.

[0066] The air intake device 130 specifically includes an air source 131, a pressure controller 132 and a pressure regulating valve 133. The air source 131 is connected to the air inlet of the air flow channel 1110 through an air intake pipeline 134 to provide heat medium gas to the air flow channel 1110. The pressure regulating valve 133 can be arranged at the outlet of the air source 131, or, as Figure 1 As shown, the pressure regulating valve 133 can also be arranged on the air inlet pipeline 134. The pressure regulating valve 133 is electrically connected to the pressure controller 132, and the pressure controller 132 can be used to control the opening of the pressure regulating valve 133 to adjust the flow rate of the heat medium gas delivered by the gas source 131. The heat medium gas can be, for example, an inert gas such as helium (He) or argon (Ar).

[0067] Electrode 1111 is provided in electrostatic chuck 111, and electrode 1111 is electrically connected to direct current (DC) power supply 140 to apply direct current voltage to electrode 1111. Exemplarily, chamber 110 further includes feed-in 1112, the top of feed-in 1112 is fixedly connected to electrostatic chuck 111, the bottom of feed-in 1112 extends from the bottom wall of chamber 110 to the outside of chamber 110, and direct current power supply 140 is connected to feed-in 1112 to feed power to electrode 1111 through feed-in 1112. In this way, electrostatic chuck 111 can adsorb and fix wafer 2000 during the process.

[0068] Figure 1The semiconductor process equipment 1000 is shown to have an electrode 1111. In this example, the specific working process of the semiconductor process equipment 1000 includes the following steps. In the adsorption step (chuck), under the premise that the process gas in the chamber 110 is excited into plasma, if the electrode 1111 is connected to the negative electrode of the DC power supply 140, the electrode 1111 loaded with a negative voltage forms a DC electric field. Under the action of the DC electric field, the free electrons inside the wafer 2000 move in a directional manner, and the area on the back of the wafer 2000 corresponding to the electrode 1111 forms a positive charge (i.e., induced charge) aggregation, and the induced charge and the electrode 1111 form a mutually attractive electrostatic attraction, so that the wafer 2000 is adsorbed and fixed on the electrostatic chuck 111. In the desorption step (dechuck), the polarity of the output voltage of the DC power supply 140 is changed, and a positive voltage is applied to the electrode 1111, so that the direction of the DC electric field changes, causing the induced charge on the wafer 2000 to move in the opposite direction, forming a neutralization effect. After the wafer 2000 restores electrical neutrality, the DC power supply 140 is turned off and the wafer 2000 is released.

[0069] Of course, in some embodiments, two electrodes 1111 may be provided, and the polarities of the two electrodes 1111 are opposite, and the two electrodes 1111 are respectively connected to the positive electrode and the negative electrode of the DC power supply 140, and the electrostatic chuck 111 is a bipolar electrostatic chuck 111. In the semiconductor process equipment 1000 of this example, in the adsorption step, the DC power supply 140 applies positive voltage and negative voltage to the two electrodes 1111 respectively. In the desorption step, the polarity of the voltage applied to the two electrodes 1111 is switched, and a reverse voltage is applied to the two electrodes 1111, or the DC power supply 140 is turned off, then the plasma is ignited, so that the wafer 2000 is desorbed.

[0070] The chamber 110 also includes a lifting needle (not shown) that can be raised and lowered relative to the electrostatic chuck 111. During operation, the semiconductor process equipment 1000 using this embodiment can first perform a desorption step, then control the lifting needle to rise to the first position, so that the wafer 2000 on the electrostatic chuck 111 is lifted up, and then use a robot to take away the desorbed wafer 2000. Alternatively, the robot places the wafer 2000 on the lifting needle located at the first position, and then controls the lifting needle to descend to the second position, so that the wafer 2000 on the lifting needle falls back onto the electrostatic chuck 111, and then performs an adsorption step to adsorb and fix the wafer 2000 on the electrostatic chuck 111. It can be seen that the lifting needle and the robot cooperate with the adsorption step or the desorption step to realize the loading and unloading of the wafer 2000 to the electrostatic chuck 111.

[0071] Based on the above description, it can be seen that Figure 2As shown, when the wafer 2000 is placed on the electrostatic chuck 111, the forces acting on the wafer 2000 include gravity G, electrostatic attraction E, support force F provided by the electrostatic chuck 111 for the wafer 2000, and pressure N generated by the heat medium gas on the wafer 2000. Gravity G and electrostatic attraction E are vertically downward, and support force F and pressure N are vertically upward. Figure 2 for Figure 1 The schematic diagram of force analysis of wafer 2000 is shown. According to Newton's third law, when electrostatic chuck 111 adsorbs wafer 2000, support force F+pressure N=gravity G+electrostatic attraction E, that is, support force F=gravity G+electrostatic attraction E-pressure N. Among them, the gravity G of wafer 2000 remains unchanged, the pressure N is related to the flow rate of the heat medium gas passed into the gap between electrostatic chuck 111 and wafer 2000, and the electrostatic attraction E is related to the adsorption voltage value on electrostatic chuck 111.

[0072] In the semiconductor process equipment 1000 such as the CCP dielectric etcher in the previous example, the flow rate of the heat medium gas remains unchanged during the process, that is, the pressure N generated by the heat medium gas on the wafer 2000 is constant. In this way, in actual applications, when the DC power supply 140 fails and the adsorption voltage value on the electrostatic chuck 111 is too small, the electrostatic attraction E is correspondingly too small. If the sum of the electrostatic attraction E and the gravity G is less than the pressure N, the heat medium gas can blow the wafer 2000 away from the electrostatic chuck 111, causing the wafer 2000 to fall into the chamber 110 and hit the chamber 110 and break. In addition, since the elimination of charge is affected by many factors, the charge on the electrostatic chuck 111 cannot be completely eliminated by adding a reverse voltage, resulting in residual charge on the top surface of the electrostatic chuck 111. The residual charge generates an adsorption force. If the residual charge is large, the electrostatic attraction E is too large, resulting in the wafer 2000 being unable to be completely desorbed. At this time, when the lifting needle rises, the wafer 2000 cannot rise with it, and the lifting needle rises and the wafer 2000 is crushed to pieces. When the semiconductor process equipment 1000 is broken, it is often necessary to shut down the machine to terminate the process and restore it to normal through manual maintenance, resulting in low production efficiency.

[0073] Based on the above description, an embodiment of the present application provides a pressure control method and a semiconductor process equipment 1000, by obtaining a support force F, understanding the adsorption state of the wafer 2000 according to the size of the support force F, and automatically adjusting the size of the pressure N accordingly, so that when certain components of the semiconductor process equipment 1000 fail or the wafer 2000 cannot be desorbed, or other situations occur, the force acting on the wafer 2000 can be kept balanced, and the adsorption state of the wafer 2000 is always kept in good condition.

[0074] In order to enable those skilled in the art to better understand the technical solution of the present invention, the pressure control method and semiconductor process equipment 1000 provided by the present invention are described in detail below in conjunction with the accompanying drawings.

[0075] Figure 3 A hardware module diagram of a semiconductor process equipment 1000 provided in an embodiment of the present application. Figure 1 and Figure 3 The semiconductor process equipment 1000 includes a voltage detection device 150 , a pressure detection device 160 and a controller 170 .

[0076] Exemplarily, the controller 170 includes at least one processor 171 and at least one memory 172. The memory 172 may be used to store program code. The memory 172 may be configured as any type of memory 172. For example, the memory 172 may be implemented as a flash memory, a read-only memory (ROM), a random access memory (RAM), a removable memory, other types of storage elements, or any combination of such storage devices.

[0077] The processor 171 can be used to execute application code and call related modules to implement the functions of the semiconductor process equipment 1000 in the embodiment of the present application. The processor 171 may include one or more processing units, for example: the processor 171 may include an application processor (application processor, AP), a modem processor, a graphics processor (graphics processing unit, GPU), an image signal processor (image signal processor, ISP), a video codec, a digital signal processor (digital signal processor, DSP), a baseband processor, and / or a neural-network processing unit (neural-network processing unit, NPU), etc. Among them, different processing units can be independent devices or integrated in one or more processors 171.

[0078] The voltage detection device 150 is used to detect the adsorption voltage value on the electrostatic chuck 111. The voltage detection device 150 is electrically connected to the controller 170 to send the detected adsorption voltage value to the controller 170. It should be particularly pointed out that in the semiconductor process equipment 1000 disclosed herein, the voltage output by the DC power supply 140 is not changed, and the adsorption voltage value on the electrostatic chuck 111 can be regarded as a constant value. Accordingly, the electrostatic attraction E in this embodiment can be regarded as a constant value.

[0079] The pressure detection device 160 may be disposed between the electrostatic chuck 111 and the wafer 2000 to detect the supporting force F of the wafer 2000 on the electrostatic chuck 111. The pressure detection device 160 is electrically connected to the controller 170. The pressure detection device 160 may be implemented by a pressure sensor.

[0080] The semiconductor process equipment 1000 disclosed herein may further include an analog input (AI) module 180, through which the voltage detection device 150 and the pressure detection device 160 are connected to the controller 170, and the voltage detection device 150 converts the collected adsorption voltage value into an analog signal and transmits it to the AI ​​module 180, and the AI ​​module 180 then sends the analog signal to the controller 170. Similarly, the pressure detection device 160 converts the collected pressure value into an analog signal and transmits it to the AI ​​module 180, and the AI ​​module 180 then sends the analog signal to the controller 170.

[0081] As disclosed herein, the controller 170 is also electrically connected to the pressure controller 132 of the air inlet device 130. The controller 170 can send a signal to the pressure controller 132 so that the pressure controller 132 controls the pressure regulating valve 133 to adjust its opening, so as to adjust the flow rate of the heat medium gas delivered to the gap, thereby achieving temperature control of the wafer 2000, and at the same time, adjusting the pressure N of the heat medium gas acting on the wafer 2000. Specifically, the controller 170 can be connected to the pressure controller 132 through an analog output (AO) module 190, and the controller 170 transmits the set value of the pressure of the heat medium gas acting on the wafer 2000 to the AO module 190, and the AO module 190 sends it to the pressure controller 132.

[0082] In a further optional example, a groove 1113 is formed on the top surface of the electrostatic chuck 111, and the gas outlet of the gas flow channel 1110 is formed on the bottom surface of the groove 1113. In this way, the gap between the top surface of the electrostatic chuck 111 and the top surface of the wafer 2000 can accommodate more flow of the heat medium gas, so as to effectively increase the temperature of the wafer 2000.

[0083] In some embodiments, the semiconductor process equipment 1000 disclosed herein may further include a temperature detection device 200, which is used to detect the temperature of the heat medium gas between the wafer 2000 and the top surface of the electrostatic chuck 111. The temperature detection device 200 may be electrically connected to the controller 170 through the AI ​​module 180 to send the detected temperature to the controller 170. Here, the temperature detection device 200 may be a temperature sensor, which may be disposed on the top surface of the electrostatic chuck 111.

[0084] In an embodiment where a heater 210 is provided inside the electrostatic chuck 111 , the controller 170 as disclosed herein is also electrically connected to the heater 210 , and the controller 170 can control the working state of the heater 210 to adjust the temperature of the electrostatic chuck 111 , thereby achieving temperature regulation of the wafer 2000 .

[0085] In order to improve the temperature control capability of the electrostatic chuck 111, so as to further accurately control the temperature of the electrostatic chuck 111, in some embodiments, a flow channel may be formed on the electrostatic chuck 111, and the semiconductor process equipment 1000 also includes a pipeline assembly and a regulating valve, one end of the pipeline assembly is connected to the flow channel, and the other end is connected to a cooling source (chiller) located outside the chamber 110, the cooling source is used to provide a coolant, and the regulating valve is arranged on the pipeline assembly to adjust the flow rate of the coolant. In this embodiment, the regulating valve is electrically connected to the controller 170, and the controller 170 can control the regulating valve to adjust its opening, thereby changing the temperature of the electrostatic chuck 111, thereby realizing the control of the temperature of the wafer 2000 during the process.

[0086] In some embodiments, the semiconductor process equipment 1000 may further include an alarm module 220 electrically connected to the controller 170. The alarm module 220 sends an alarm message, for example, in the form of text or sound and any combination of the above methods. In this embodiment, the alarm module 220 may specifically be a display or a buzzer. Alternatively, the alarm module 220 may also send the alarm message to a terminal device associated with the semiconductor process equipment 1000. In this embodiment, the semiconductor process equipment 1000 may further include a communication module, and the semiconductor process equipment 1000 communicates with the terminal device through the communication module. Taking the wireless communication module 230 as an example, the wireless communication module 230 may be implemented as one or more wireless interfaces, Bluetooth interfaces, near field communication interfaces, Wi-Fi interfaces, or any traditional communication interfaces.

[0087] In some embodiments, the semiconductor process equipment 1000 may further include a first counter 240 , which is connected to the controller 170 , and is used to count the number of marking times n.

[0088] In some embodiments, the semiconductor process equipment 1000 may further include a second counter 250 and a third counter 260, both of which are connected to the controller 170, the second counter 250 is used to count the number of executions K of the step-down operation, and the third counter 260 is used to count the number of executions M of the step-up operation.

[0089] In some embodiments, the semiconductor process equipment 1000 may further include a timer 270 . The timer 270 is connected to the controller 170 , and the timer 270 is used for timing.

[0090] In some embodiments, the semiconductor process equipment 1000 may further include a focus ring 280

[0091] (FR), the focusing ring 280 is sleeved on the outer side of the electrostatic chuck 111 , and the focusing ring 280 surrounds the wafer 2000 to adjust the electric field and temperature distribution at the edge of the wafer 2000 .

[0092] It is understood that the structure illustrated in the embodiment of the present invention does not constitute a specific limitation on the semiconductor process equipment 1000. In other embodiments of the present invention, the semiconductor process equipment 1000 may include more or fewer components than shown in the figure, or combine some components, or separate some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0093] Figure 4 A flow chart of a pressure control method provided by an embodiment of the present application is shown. For the semiconductor process equipment 1000 described above, a pressure control method can be executed to control the pressure N applied by the heat medium gas to the wafer 2000. The specific process of the pressure control method can be found in Figure 4 ,include:

[0094] S1, when the wafer is on the electrostatic chuck, obtaining the supporting force provided by the electrostatic chuck for the wafer.

[0095] As can be seen from the foregoing, when the wafer 2000 is placed on the electrostatic chuck 111 , the support force F can be obtained in real time by acquiring the collected information of the pressure detection device 160 in real time.

[0096] S2, determining whether the supporting force is within a theoretical supporting force range; wherein the theoretical supporting force range is pre-set according to the weight of the wafer.

[0097] It is understandable that the weight of the wafer 2000 needs to be determined in advance before executing S2, and the theoretical support force range is set according to the weight of the wafer 2000. The weight of the wafer 2000 is the gravity G of the wafer 2000. The process flow of the wafer 2000 needs to go through multiple process steps. Since the process steps are affected by various factors, the weights of different wafers 2000 often differ.

[0098] In this embodiment, the implementation method of determining the weight of the wafer 2000 is not limited.

[0099] In some embodiments, a gravity detection device can be used to weigh the wafer 2000 when the robot transfers the wafer 2000 to the electrostatic chuck 111. In this example, the weight of the wafer 2000 can be determined by receiving the collection results of the gravity detection device, and the theoretical support force range can be set accordingly.

[0100] In other methods, S1 is implemented by the following steps: i) when the wafer is on the electrostatic chuck, stop supplying heat medium gas between the electrostatic chuck 111 and the wafer 2000; ii) obtain the supporting force F provided by the electrostatic chuck 111 for the wafer 2000 and the adsorption voltage value on the electrostatic chuck 111; iii) determine the electrostatic attraction E according to the adsorption voltage value; iv) calculate the gravity G of the wafer 2000 = supporting force F - electrostatic attraction E according to the supporting force F and the electrostatic attraction E, and set the theoretical supporting force range according to the gravity G; v) supply heat medium gas between the electrostatic chuck 111 and the wafer 2000 so that the pressure applied by the heat medium gas to the wafer 2000 reaches the current value, and re-obtain the supporting force F provided by the electrostatic chuck 111 for the wafer 2000. In this embodiment, the heat medium gas is stopped from being supplied and the pressure N is controlled to be 0. Based on this, the gravity of the wafer 2000 is calculated using Newton's third law to determine the weight of the wafer 2000 before S2.

[0101] Of course, as a preferred method, as described later, in an implementation scheme in which a plurality of support pillars 120 are provided on the top surface of the electrostatic chuck 111, a plurality of pressure detection devices 160 are arranged one by one at the top ends of the plurality of support pillars 120. In step S1, when the wafer is on the electrostatic chuck, no adsorption force is applied and no heat transfer gas is introduced, and the gravity G of the wafer 2000 itself can be directly obtained based on the support force F detected by the pressure detection device 160.

[0102] The theoretical support force range is [lower limit, upper limit], where the lower limit is less than the upper limit. As described above, in the constant formula of support force F + pressure N = gravity G + electrostatic attraction E, the gravity G and electrostatic attraction E of the wafer 2000 remain unchanged, and the support force F and pressure N are variables. When the pressure N changes, the support force F changes accordingly, and the support force F does not exceed the gravity G.

[0103] Here, in combination with previous process steps, the lower limit and upper limit can be reasonably set according to the relationship between the empirical value of the maximum supporting force F and the empirical value of the minimum supporting force F corresponding to a good adsorption state of the wafer 2000 in the adsorption step and the weight of the wafer 2000.

[0104] In this embodiment, the lower limit value can be set to 0.05G and the upper limit value can be set to 0.1G, that is, the theoretical support force range is [0.05G, 0.1G]. Among them, when the support force F satisfies: F<0.05G, there is a high risk that the wafer 2000 is blown away from the electrostatic chuck 111; when the support force F satisfies: F>0.1G, although the wafer 2000 can be stably placed on the electrostatic chuck 111, the wafer 2000 is easily pushed up by the lifting needle and broken into pieces. In general, when F<0.05G or F>0.1G, the wafer 2000 is prone to risks during the process. On the contrary, when the support force F satisfies: 0.05G≤F≤0.1G, it can be determined that the adsorption state of the wafer 2000 is good.

[0105] In summary, the judgment result of step S2 can be used to determine the adsorption state of the wafer 2000. When the support force F is within the theoretical support force range, it indicates that the adsorption state of the wafer 2000 is good, and there is no need to adjust the pressure N; when the support force F is not within the theoretical support force range, it indicates that the adsorption state of the wafer 2000 is not good, and the pressure N needs to be adjusted to reduce the risk of the wafer 2000 being blown away or pushed against and broken.

[0106] S3, if the supporting force is not within the theoretical supporting force range, the heat medium gas is controlled to perform a pressure adjustment operation so that the pressure increases or decreases from the current value.

[0107] In this step, a signal can be sent to the pressure controller 132, and the pressure controller 132 receives the signal and controls the pressure regulating valve 133 to adjust, so that the opening of the pressure regulating valve 133 is increased to increase the flow rate of the heat medium gas delivered to the air flow channel 1110, and the pressure N rises accordingly, or the opening of the pressure regulating valve 133 is reduced to reduce the flow rate of the heat medium gas delivered to the air flow channel 1110, and the pressure N decreases accordingly.

[0108] It should be understood that the current value in this step can be a set value, that is, the semiconductor process equipment 1000 to which the pressure control method is applied has pre-set pressure N at the beginning of the process. Specifically, a signal can be sent to the pressure controller 132 before S2, and the initial opening of the pressure regulating valve 133 can be set by the pressure controller 132, thereby achieving the setting of the current value. Among them, the current value can be reasonably set according to the empirical value of the pressure N corresponding to the good adsorption state of the wafer 2000 in the adsorption step in combination with the previous process.

[0109] S4, after performing the pressure adjustment operation, the current value is updated, and the step of obtaining the supporting force is returned to be executed until the supporting force is within the theoretical supporting force range.

[0110] After S3, the pressure N changes, and in this step, the changed pressure N can be assigned to the current value to update the current value. In this way, return to S1, and the updated current value can be used as a basis to continue to adjust the pressure N to ensure accurate adjustment.

[0111] The control method of the pressure applied by the heat medium gas to the wafer 2000 of this embodiment obtains the support force F of the electrostatic chuck 111 on the wafer 2000 and determines whether the support force F is within the theoretical support force range. According to the judgment result, it can be known whether there is an abnormality in the adsorption state of the wafer 2000. In this embodiment, by setting the adsorption voltage value on the electrostatic chuck 111 to a constant value, the gravity G and the electrostatic attraction E of the wafer 2000 are both fixed, and the pressure N is changed to make the wafer 2000 reach a good adsorption state. In this way, when the support force F exceeds the theoretical support force range, the pressure N can be adjusted by controlling the heat medium gas until the pressure N is adjusted to make the support force F within the theoretical support force range, and the wafer 2000 can maintain a good adsorption state in the subsequent process. Therefore, using the pressure control method of this embodiment, the pressure N applied by the heat medium gas to the wafer 2000 is not a constant value, but can be adjusted automatically.

[0112] In this way, when the DC power supply 140 of the semiconductor process equipment 1000 fails and causes the adsorption voltage value to be too small, the electrostatic attraction E is too small, and the pressure N is automatically adjusted, so that the force acting on the wafer 2000 can still remain balanced, and the wafer 2000 can be stably adsorbed on the electrostatic chuck 111 to prevent the wafer 2000 from being blown away from the electrostatic chuck 111 and hitting the chamber 110 to cause fragments.

[0113] When a large amount of negative charges newly generated during the process accumulate on the electrostatic chuck 111, an attraction is generated between the negative charges and the induced charges, and the electrostatic attraction E is too large, resulting in the wafer 2000 not being completely desorbed, the pressure N is automatically adjusted to still keep the force on the wafer 2000 balanced, and the wafer 2000 can be stably adsorbed on the electrostatic chuck 111. As a result, when the lifting needle rises, the wafer 2000 can rise with it to prevent the wafer 2000 from being crushed by the lifting needle, and the semiconductor process equipment 1000 does not need to be shut down for maintenance, which saves unnecessary process termination, improves production efficiency, and reduces the generation of defective products.

[0114] Moreover, compared with the lower limit and upper limit of the theoretical support force range being preset constants, the present embodiment takes into account the different weights of different wafers 2000, by designing the lower limit and upper limit of the theoretical support force range to be associated with the weight of the wafer 2000. In this way, even if there are slight differences in the weights of different wafers 2000, when the pressure control method of this embodiment is applied, the theoretical support force ranges corresponding to different wafers 2000 are also different. Therefore, on the one hand, the judgment result of S2 can be related to the weight of the wafer 2000, and thus the adsorption state of the wafer 2000 can be more accurately determined. On the other hand, in order to make the support force F meet the corresponding theoretical support force range, the pressure N is adjusted more accurately, so that the adjustment effect of the adsorption state of the wafer 2000 is better.

[0115] The specific process of S3 disclosed in this article may include the following steps:

[0116] S31: If the supporting force is not within the theoretical supporting force range, the supporting force is compared with any one of the lower limit value and the upper limit value of the theoretical supporting force range to obtain a comparison result.

[0117] S32, when the comparison result shows that the supporting force is greater than the upper limit value, determining the pressure regulating operation as a pressure increasing operation to increase the pressure from the current value.

[0118] S33, when the comparison result is that the supporting force is less than the lower limit value, determining the pressure regulating operation as a pressure reducing operation, so that the pressure is reduced from the current value.

[0119] Since the gravity G and electrostatic attraction E of the wafer 2000 remain unchanged, the support force F can change with the pressure N. It should be pointed out that in the actual application process, the scenario where the support force F is greater than the upper limit value is, for example, the groove 1113 on the top surface of the electrostatic chuck 111 is contaminated by the deposition of reaction byproducts, and the heat medium gas cannot fully flow into the gap between the wafer 2000 and the electrostatic chuck 111, resulting in too small a pressure N. There is also an example in which a large amount of negative charges newly generated during the process accumulate on the electrostatic chuck 111. This is, by performing a boosting operation, the pressure N increases, and the support force F is adjusted accordingly to reduce the risk of the wafer 2000 when the support force F is too large, which can reduce the risk of the wafer 2000 being hit by the lifting needle and broken.

[0120] When the comparison result shows that the supporting force F is less than the lower limit, the pressure N is reduced by performing a depressurization operation, and the supporting force F is increased accordingly to reduce the risk of the wafer 2000 when the supporting force F is too small, thereby reducing the risk of the wafer 2000 being blown off the electrostatic chuck 111. In this way, the wafer 2000 reaches a good adsorption state.

[0121] In a feasible implementation, the specific implementation process of S33 may include the following steps.

[0122] S331, when the comparison result is that the supporting force is less than the lower limit value, determine whether the supporting force meets the first preset condition and the second preset condition; wherein the first preset condition is that the supporting force is 0, and the second preset condition is that the supporting force is 0 for the first time.

[0123] Here, judging whether the supporting force F satisfies the first preset condition and judging whether the supporting force F satisfies the second preset condition can be performed simultaneously. Alternatively, S331 includes sub-step a) judging whether the supporting force F satisfies the first preset condition and sub-step b) judging whether the supporting force F satisfies the second preset condition, and sub-step a) and sub-step b) are performed successively, and the execution order is not limited. It should be pointed out that the second preset condition includes the first preset condition. Therefore, if the supporting force F does not satisfy the first preset condition, the supporting force F must not satisfy the second preset condition. In this way, in an embodiment where sub-step a) is executed before sub-step b), if the judgment result of sub-step a) is not satisfied, it is not necessary to execute sub-step b) to obtain the judgment result of sub-step b) is also not satisfied. In this way, the operating efficiency of the pressure control method can be effectively improved.

[0124] S332, when the supporting force meets the first preset condition and the second preset condition, the critical pressure value is calculated according to the weight and the adsorption voltage value on the electrostatic chuck, the critical pressure value is assigned to the current value, and the step of obtaining the supporting force is returned to be executed.

[0125] S333: When the supporting force does not satisfy at least one of the first preset condition and the second preset condition, determine that the pressure regulating operation is a pressure reducing operation to reduce the pressure from the current value.

[0126] Combination Figure 1 and Figure 2 It can be seen that when the pressure N = electrostatic attraction E + gravity G, the supporting force F is 0. At this time, the wafer 2000 is in a critical adsorption state, that is, the wafer 2000 is blown by the hot medium gas and there is a distance between it and the top surface of the electrostatic chuck 111, so that the wafer 2000 floats on the electrostatic chuck 111 but is not blown away.

[0127] It can be seen that if the judgment result of S331 is yes, it means that the support force F is 0 for the first time, indicating that the wafer 2000 is in the critical adsorption state for the first time, then S332 is executed. Specifically, the electrostatic attraction E is determined according to the adsorption voltage value on the electrostatic chuck 111, and the critical pressure value N of the pressure N is calculated according to the electrostatic attraction E and the gravity G. CV = electrostatic attraction E + gravity G. Update the current value to the critical pressure value N CV After that, the updated current value is used as the basis to return to execute S1.

[0128] Thus, according to the method of this embodiment, when S331 is executed again, the support force F is 0 but not 0 for the first time, and the judgment result must be no, and then S333 is executed, and the pressure N is increased from the critical pressure value N CV The support force F decreases, and accordingly, the wafer 2000 changes from a critical adsorption state to a state where it is placed on the electrostatic chuck 111 , so as to improve the adsorption state of the wafer 2000 and thereby reduce the risk of the wafer 2000 being blown off the electrostatic chuck 111 .

[0129] In general, the present embodiment is configured such that, based on the comparison result that the supporting force is less than the lower limit value, by further judging whether the supporting force satisfies the first preset condition and the second preset condition, when the wafer 2000 is in the critical adsorption state for the first time according to the judgment result, by calculating the critical pressure value N CV , and update the pressure N to the critical pressure value N CV Finally, adjust the pressure N to accurately adjust the pressure N.

[0130] It is worth pointing out that such a design can also be performed when the support force F satisfies the first preset condition but does not satisfy the second preset condition, that is, when the support force F is not 0 for the first time and the wafer 2000 is not in the critical adsorption state for the first time, S333 is executed to perform a pressure reduction operation so that the pressure is increased from the updated current value (i.e., the critical pressure value N CV ) decreases without having to repeatedly calculate the critical pressure value N CV , improving the pressure control efficiency.

[0131] As disclosed in this article, the specific process of "determining whether the supporting force meets the second preset condition" in S331 can be: determining whether the marking number n is the starting value. In addition, after executing S331, the pressure control method of this embodiment further includes S334.

[0132] S334: When the supporting force satisfies the first preset condition and the second preset condition, the marking times n is increased by 1.

[0133] The marking times n can be counted by the first counter 240. At this time, S334 can be achieved by controlling the count of the first counter 240 to be increased by 1.

[0134] In this embodiment, whenever the judgment result of S331 is that the support force is 0 and the number of markings n is the starting value, it means that the support force satisfies the first preset condition and the second preset condition. After that, S334 is executed, the number of markings is increased by 1, and the number of markings n changes. In this way, according to the method of this embodiment, when S331 is executed again, even if the support force is 0, the number of markings n is no longer the starting value, so it can be determined that the support force F is not 0 for the first time, and the judgment result of S331 is no, and then S333 is executed. This embodiment adopts this method to accurately determine whether the wafer 2000 is in a critical adsorption state for the first time.

[0135] It should be noted that the execution order of the above S332 and S334 is not limited, and they can be executed simultaneously or one after another, which is not limited in this embodiment.

[0136] In a specific example, a starting value of the marking times n may be set before S2. For example, the starting value may be an integer such as 0, 1, or 2, and this embodiment does not impose any specific limitation on this.

[0137] In the embodiment where the starting value is 0, the pressure control method disclosed herein may further perform S5 after S2.

[0138] S5, if the supporting force is within the theoretical supporting force range, the marking times n are cleared.

[0139] In this way, the accuracy of the judgment when S331 is executed again is ensured, so as to ensure that the pressure control method can be executed cyclically.

[0140] In addition, in the embodiment where the initial value of the marking number n is 0, the pressure control method disclosed herein can clear the marking number n when the wafer is on the electrostatic chuck 111. In this way, the pressure control method can continue to run when the wafer 2000 is out of the adsorption state by initializing by clearing the marking number n.

[0141] It can be understood that the specific implementation process of S333 includes the following possible situations.

[0142] Optionally, in the first case, when the supporting force F satisfies the first preset condition but does not satisfy the second preset condition, a depressurization operation is performed. That is, when the supporting force F is less than the lower limit value and the supporting force F is 0, but the supporting force F is not 0 for the first time, that is, when the wafer 2000 is not in the critical adsorption state for the first time, a depressurization operation is performed, the pressure N decreases, and the supporting force F increases accordingly, so that the supporting force F satisfies the theoretical supporting force range to improve the adsorption state of the wafer 2000. Moreover, in this example, when the depressurization operation is performed, the change in pressure N is the first set increment ΔT1. In combination with the foregoing, it can be seen that the pressure N can be controlled by adjusting the opening of the pressure regulating valve from the current value (that is, the critical pressure value NCV ) is reduced by ΔT1. Moreover, it should be noted that after the pressure N is reduced by the first set increment ΔT1 from the current value, if the support force F is still 0, the pressure N is controlled to be reduced by the first set increment ΔT1 again.

[0143] Optionally, in the second case, if the support force F does not satisfy the first preset condition, the support force F must also not satisfy the second preset condition, and the pressure reduction operation is performed. Moreover, when the pressure reduction operation is performed, the change in the pressure N is negatively correlated with the number of executions K of the pressure reduction operation. And each time the pressure reduction operation is performed, the number of executions K of the pressure reduction operation is correspondingly updated.

[0144] As can be seen from the foregoing, when the support force F is less than the lower limit but not 0, a pressure reduction operation is performed, the pressure N decreases, and the support force F increases accordingly, so that the support force F meets the theoretical support force range to improve the adsorption state of the wafer 2000.

[0145] In addition, since the change amount of the pressure N is negatively correlated with the number of execution times K of the pressure reduction operation, the change amount of the pressure N gradually decreases as the number of execution times K of the pressure reduction operation increases.

[0146] Based on the above description, it can be known that according to the method of this embodiment, when the wafer 2000 is not in the critical adsorption state for the first time, the wafer 2000 floats on the electrostatic chuck 111, and the pressure N is continuously controlled to drop significantly, so that the wafer 2000 can be restored to the adsorption state as soon as possible, so as to reduce the risk of the wafer 2000 that is not adsorbed and fixed on the electrostatic chuck 111 being broken. When the support force F is less than the lower limit value and the wafer 2000 is in the adsorption state, the change amount of the pressure N is gradually reduced, that is, the pressure N is fine-tuned, while improving the adsorption state of the wafer 2000, so that the wafer 2000 can be stably adsorbed on the electrostatic chuck 111, it can also avoid excessive adjustment of the pressure N, so as to optimize the pressure N as quickly as possible within a limited number of times to make the support force F reach the theoretical support force range.

[0147] Exemplarily, when the number of executions K of the pressure reduction operation is set to 1, the corresponding change in pressure N is 50; when the number of executions K of the pressure reduction operation is set to 2, the corresponding change in pressure N is 30; when the number of executions K of the pressure reduction operation is set to 3, the corresponding change in pressure N is 15.

[0148] As an alternative embodiment, the support force F does not meet the first preset condition. When the pressure reduction operation is performed, the change in pressure N can be equal to the ratio of the second set increment ΔT2 to the number of executions K of the pressure reduction operation. Specifically, the pressure N is controlled to drop according to the following relationship: current value T-second set increment ΔT2 / number of executions K of the pressure reduction operation=new current value T'. In this embodiment, the change in pressure N is inversely proportional to the number of executions K of the pressure reduction operation, and the change in pressure N decreases successively, so that the pressure N can be gradually optimized to make the support force reach the theoretical support force range. At the same time, excessive adjustment of pressure N can be avoided.

[0149] As in the method disclosed herein, when the boost operation is performed, the change in pressure N is negatively correlated with the number of executions M of the boost operation; and each time the boost operation is performed, the number of executions M of the boost operation is correspondingly updated. In this embodiment, when the support force F is higher than the upper limit value, the change in pressure N is inversely proportional to the number of executions M of the boost operation, and the change in pressure N decreases successively, so that the pressure N can be gradually optimized to make the support force reach the theoretical support force range, and at the same time, excessive adjustment of the pressure N can be avoided.

[0150] In some achievable embodiments, when the number of executions M of the boost operation is 1, the corresponding change in pressure N is 50; when the number of executions M of the boost operation is 2, the corresponding change in pressure N is 30; and so on.

[0151] In other achievable manners, during the boost operation, the change in pressure N may be equal to the ratio of the second set increment ΔT2 to the number of executions of the boost operation M. Specifically, the pressure N is controlled to rise according to the following relationship: current value T+second set increment ΔT2 / number of executions of the boost operation M=new current value T'.

[0152] Exemplarily, the second counter 250 may be used to count the number of executions K of the pressure reduction operation, and the third counter 260 may be used to count the number of executions M of the pressure increase operation. In this embodiment, the pressure control method may further include: when the wafer is on the electrostatic chuck, setting the initial values ​​of the second counter 250 and the third counter 260; wherein the initial values ​​are 0 or 1.

[0153] In an implementation scheme in which the initial value of the second counter 250 and the third counter 260 is 1, the above-mentioned “each time a step-down operation is performed, the corresponding execution count K of the step-down operation is updated” can be specifically that after the step-down operation is performed, the count of the second counter 250 is increased by 1, so that the execution count K of the step-down operation is increased by 1; the above-mentioned “each time a step-up operation is performed, the corresponding execution count M of the boost operation is updated” can be specifically that after the boost operation is performed, the count of the third counter 260 is increased by 1, so that the execution count M of the boost operation is increased by 1.

[0154] In an implementation scheme in which the initial value of the second counter 250 and the third counter 260 is 0, the above-mentioned “each time a step-down operation is performed, the corresponding execution count K of the step-down operation is updated” can specifically be that before the step-down operation is performed, the count of the second counter 250 is increased by 1, so that the execution count K of the step-down operation is increased by 1; the above-mentioned “each time a step-up operation is performed, the corresponding execution count M of the boost operation is updated” can specifically be that before the step-down operation is performed, the count of the third counter 260 is increased by 1, so that the execution count M of the boost operation is increased by 1.

[0155] When the initial values ​​of the second counter 250 and the third counter 260 are 0, the counts of the second counter 250 and the third counter 260 can be further reset to zero when the wafer is on the electrostatic chuck. The second counter 250 and the third counter 260 are reset to zero for initialization, so that the pressure control method can continue to run when the wafer 2000 is out of the adsorption state.

[0156] The pressure control method disclosed herein may further perform S6 after S2 .

[0157] S6: If the supporting force is within the theoretical supporting force range, the number of executions K of the pressure reduction operation and the number of executions M of the pressure increase operation are reset to initial values.

[0158] In this way, the accuracy of the pressure increasing operation and the pressure reducing operation is ensured, so as to ensure that the pressure control method can be effectively cyclically executed.

[0159] As disclosed herein, the first set increment ΔT1 and the second set increment ΔT2 can be set when the wafer is on the electrostatic chuck. It should be understood that the first set increment ΔT1 and the second set increment ΔT2 can be set to be the same or different, and this embodiment does not specifically limit this.

[0160] Figure 5 FIG. 1 is a schematic diagram showing the structure of another semiconductor process equipment 1000 provided in an embodiment of the present application. In a specific example of the present application, Figure 5 As shown, the semiconductor process equipment 1000 further includes a plurality of support pillars 120 vertically disposed on the top surface of the electrostatic chuck 111, and the wafer 2000 is placed on the support pillars 120. That is, each support pillar 120 abuts against the back side of the wafer 2000 to support the wafer 2000.

[0161] Figure 6 for Figure 5 FIG. 1 is a schematic diagram showing the relationship between the electrostatic chuck 111 and a plurality of support pillars 120 in the semiconductor process equipment 1000. The number of the support pillars 120 can be, for example, Figure 6It should be noted that the plurality of support columns 120 are evenly distributed around the electrostatic chuck 111 so that the wafer 2000 can evenly apply a weight pressure P to each support column 120 , thereby ensuring that the support columns 120 can stably support the wafer 2000 .

[0162] It should be understood that, taking the number of support pillars 120 as i, i is a positive integer, i≥2. When the wafer 2000 is in the adsorption state and the wafer 2000 is placed on the support pillars 120, the gravity of the wafer 2000 acts on each support pillar 120 together, and accordingly, each support pillar 120 applies a force to the wafer 2000, and the sum of the forces applied by all support pillars 120 to the wafer 2000 is the support force F of the electrostatic chuck 111 on the wafer 2000. It can be seen that the force applied by the i-th support pillar 120 to the wafer 2000 is the component force F i , the sum of the component forces of all support pillars 120 on the wafer 2000 ΣF i It is equal to the supporting force F of the electrostatic chuck 111 on the wafer 2000 .

[0163] In the embodiment in which a plurality of support columns 120 are provided on the top surface of the electrostatic chuck 111, a plurality of pressure detection devices 160 are provided correspondingly, and the plurality of pressure detection devices 160 are arranged one by one on the top of the plurality of support columns 120, and the pressure detection devices 160 can be used to detect the component force F of each support column 120 on the wafer 2000. i .

[0164] In this example, the specific process of S1 can be to obtain the force component F detected by each pressure detection device 160. i , and then calculate the sum of the component forces of all support pillars 120 on the wafer 2000 ΣF i , determine ΣF i is the supporting force F.

[0165] In addition, in this example, after S1 and before S2, the pressure control method may further include the following steps.

[0166] S201, determining whether the difference between the component forces corresponding to every two support columns is less than a target threshold; wherein the target threshold is a ratio of the weight to a characteristic value, and the characteristic value is equal to the number of support columns minus 1.

[0167] S202: If not, an alarm message is issued, where the alarm message is used to indicate that the adsorption state of the wafer is abnormal.

[0168] S203: If yes, execute S2.

[0169] S201 can be used to determine the specific i -F i-1|<G / (i-1) is true. It can be understood that, if the pressure regulating valve 133 is closed and the electrode 1111 is not energized, that is, the electrostatic attraction E and the pressure N are 0, then the ideal state of the wafer 2000 is: all the support columns 120 are against the wafer 2000, and the gravity of the wafer 2000 acts evenly on each support column 120, then the component force F of each support column 120 on the wafer 2000 is i Both are equal to G / i.

[0170] It can be seen that if the judgment result of S201 is |F i -F i-1 |<G / (i-1) does not hold, that is, |F i -F i-1 | is greater than or equal to G / (i-1), then the absolute value of the difference between the component forces corresponding to any two support pillars 120 is not equal to G / i, and is greater than or equal to G / (i-1), which means that one of the two support pillars 120 does not support the wafer 2000, indicating that although the wafer 2000 is in an adsorption state, the support pillar 120 does not support the wafer 2000, the wafer 2000 is not stably placed on the electrostatic chuck 111, and the adsorption state of the wafer 2000 is abnormal.

[0171] For example, when there are two support columns 120, if the absolute value of the difference between the component forces corresponding to the two support columns 120 is greater than or equal to the gravity G, then only one support column 120 supports the wafer 2000. For example, when there are three support columns 120, if the absolute value of the difference between the component forces corresponding to the two support columns 120 is equal to G / 2, then only two of the support columns 120 support the wafer 2000.

[0172] In S202, the alarm module 220 may be controlled to issue an alarm message to prompt the user that the adsorption state of the wafer 2000 is abnormal. The alarm module 220 may be a display, and the user may know that the adsorption state of the wafer 2000 is abnormal according to the text displayed on the display. The alarm module 220 may be a buzzer, and the user may know that the adsorption state of the wafer 2000 is abnormal according to the sound emitted by the buzzer. The alarm module 220 may be a terminal device, and the user may know that the adsorption state of the wafer 2000 is abnormal according to the information received by the terminal device.

[0173] In this embodiment, by judging whether the force of each support column 120 on the wafer 2000 is balanced, it can be used to judge whether each support column 120 is used to support the wafer 2000, and then judge whether the adsorption state of the wafer 2000 is abnormal. When the adsorption state of the wafer 2000 is abnormal, an alarm message is issued to prompt the user. In this way, the user can repair the semiconductor process equipment 1000 as soon as possible, so that the semiconductor process equipment 1000 can be restored to the state where all support columns 120 are against the wafer 2000, thereby reducing the defective rate of the wafer 2000.

[0174] In some embodiments, when the wafer is on the electrostatic chuck, S301 is further executed to start timing. On this basis, before executing S4, the pressure control method can further perform the following steps.

[0175] S302, determining whether the timing time exceeds a preset time.

[0176] S303: If yes, an alarm message is issued, and the alarm message is used to indicate that the adsorption state of the wafer is abnormal.

[0177] The timing time exceeding the preset time means that some parameters of the semiconductor process equipment 1000 have changed or some components of the semiconductor process equipment 1000 have failed, resulting in too long operation time of S1 to S3 when the pressure control method is applied to adjust the pressure N. The implementation of this step can be similar to the implementation of S201 above, and this embodiment will not be repeated here.

[0178] S304, if not, execute S4.

[0179] This embodiment is designed in this way, when the processor 171 executes the application code to implement the pressure control method of the embodiment of the present application, it starts timing, and when the timing time exceeds the preset time, an alarm is sounded to remind the user that there is a fault in the semiconductor process equipment 1000. In this way, the user can repair the semiconductor process equipment 1000 as soon as possible according to the alarm information.

[0180] Among them, S301 can be implemented by controlling the timing of the timer 270, and S302 is to determine whether the timing time of the timer 270 exceeds the preset time. In order to ensure that the judgment result of S302 is accurate when the pressure control method is executed again, so that the pressure control method can be executed cyclically, the pressure control method can also execute S305 after S2.

[0181] S305: If the supporting force is within the theoretical supporting force range, clear the timing time to 0.

[0182] This step can be specifically achieved by resetting the timing of the timer 270 to zero.

[0183] As a further optional embodiment, the pressure control method disclosed herein can clear the timing time T of the timer 270 when the wafer 2000 is located on the electrostatic chuck 111. That is, when the processor 171 executes the application code to implement the pressure control method of the embodiment of the present application, it clears the timer 270. In this way, by clearing the timing time T to initialize, the pressure control method can continue to run when the wafer 2000 is out of the adsorption state.

[0184] Based on any of the above embodiments, after S2, the pressure control method may further perform the following steps.

[0185] S401, if the supporting force is within the theoretical supporting force range, obtaining the temperature of the heat medium gas between the wafer and the electrostatic chuck.

[0186] S402, when the temperature does not meet the preset threshold, controlling the temperature control device for adjusting the temperature of the electrostatic chuck to adjust the temperature of the heat medium gas.

[0187] In S401, the temperature of the heat medium gas can be obtained by receiving the information collected by the temperature detection device 200. In S402, the temperature control device can be specifically at least one of the heater 210 and the cooling source. The temperature of the electrostatic chuck 111 is controlled by controlling the power or working time of the heater 210, and the heat medium gas exchanges heat with the electrostatic chuck 111, thereby adjusting the temperature of the heat medium gas. The temperature of the electrostatic chuck 111 can also be controlled by controlling the flow rate of the coolant delivered by the cooling source, thereby adjusting the temperature of the heat medium gas.

[0188] Combined with the above description, it can be known that the change in the flow rate of the heat medium gas delivered to the gap will not only cause the pressure N to change, but also cause the temperature of the heat medium gas and the wafer 2000 to change. Therefore, this embodiment takes into account that after the pressure N is adjusted so that the support force F meets the theoretical support force range, the temperature of the wafer 2000 will change accordingly. After that, the temperature is adjusted by controlling the temperature control device to avoid a large deviation between the temperature of the wafer 2000 and the preset threshold, so as to ensure that the temperature of the wafer 2000 can still be accurately controlled.

[0189] Figure 7 A flow chart of another pressure control method provided in an embodiment of the present application. In a specific example, Figure 7 As shown, the specific process of the pressure control method includes the following steps.

[0190] S501, the marking times n, the timing time T, the execution times K of the voltage reduction operation and the execution times M of the voltage increase operation are initialized to zero.

[0191] S502, when the wafer is on the electrostatic chuck, obtain the weight of the wafer and start timing.

[0192] S503, according to the weight, set the theoretical support force range to [0.05G, 0.1G].

[0193] S504, setting the current value of the pressure to X, and setting the second set increment and the first set increment to ΔX.

[0194] S505, obtaining the component forces of each supporting column acting on the wafer, and determining the supporting force according to the component forces.

[0195] S506, determine whether the absolute value of the difference between the component forces corresponding to every two support columns is less than the target threshold; the target threshold is equal to weight / number of support columns-1; if not, execute S507; if so, execute S508.

[0196] S507, issue an alarm message.

[0197] S508, determine whether the supporting force is within the theoretical supporting force range; if so, execute S509; if not, execute S510.

[0198] S509, clearing the marking times n, the timing time T, the execution times K of the voltage reduction operation and the execution times M of the voltage increase operation.

[0199] S510, determine whether the supporting force is less than 0.05G; if so, execute S511; if not, execute S515.

[0200] S511, determine whether the supporting force is 0; if so, execute S512; if not, execute S516.

[0201] S512, determine whether the marking number n is 0; if so, execute S513; if not, execute S517.

[0202] S513, calculate the critical pressure value according to the weight and the adsorption voltage value on the electrostatic chuck, assign the critical pressure value to the current value, increase the marking times n by 1, and continue to execute S514.

[0203] S514, determine whether the timing time T exceeds the preset time; if so, execute S507; if not, execute S505.

[0204] S515, increase the number of executions of the pressure-increasing operation M by 1, control the heat medium gas so that the pressure increases by ΔX / M from the current value X, assign the adjusted pressure X+ΔX / M to the current value so that the current value is updated, and return to execute S514.

[0205] S516, increase the number of executions K of the pressure reduction operation by 1, control the heat medium gas so that the pressure decreases by ΔX / K from the current value X, assign the adjusted pressure X-ΔX / K to the current value so that the current value is updated, and return to execute S514.

[0206] S517, control the heat medium gas so that the pressure decreases by ΔX from the current value X, assign the adjusted pressure X-ΔX to the current value so that the current value is updated, and return to execute S514.

[0207] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A pressure control method for controlling the pressure applied by a heat medium gas to a wafer, characterized in that: include: When the wafer is on the electrostatic chuck, obtaining a supporting force provided by the electrostatic chuck for the wafer; Determining whether the supporting force is within a theoretical supporting force range; wherein the theoretical supporting force range is pre-set according to the weight of the wafer; If the supporting force is not within the theoretical supporting force range, controlling the heat medium gas to perform a pressure adjustment operation so that the pressure increases or decreases from a current value; After performing the pressure adjustment operation, the current value is updated, and the step of obtaining the supporting force is returned to be executed until the supporting force is within the theoretical supporting force range.

2. The pressure control method according to claim 1, characterized in that: If the supporting force is not within the theoretical supporting force range, controlling the heat medium gas to perform a pressure adjustment operation so that the pressure increases or decreases from a current value specifically includes: If the supporting force is not within the theoretical supporting force range, comparing the supporting force with any one of a lower limit value and an upper limit value of the theoretical supporting force range to obtain a comparison result; When the comparison result shows that the supporting force is greater than the upper limit value, determining that the pressure regulating operation is a pressure increasing operation, so that the pressure increases from the current value; When the comparison result is that the supporting force is less than the lower limit value, the pressure regulating operation is determined to be a pressure reducing operation, so that the pressure is reduced from the current value.

3. The pressure control method according to claim 2, characterized in that: When the comparison result shows that the supporting force is less than the lower limit value, determining that the pressure regulating operation is a pressure reducing operation so as to reduce the pressure from the current value specifically includes: When the comparison result is that the supporting force is less than the lower limit value, determining whether the supporting force satisfies a first preset condition and a second preset condition; wherein the first preset condition is that the supporting force is 0, and the second preset condition is that the supporting force is 0 for the first time; When the supporting force does not satisfy at least one of the first preset condition and the second preset condition, the pressure regulating operation is determined to be a pressure reducing operation, so that the pressure is reduced from a current value.

4. The pressure control method according to claim 3, characterized in that: When the supporting force satisfies the first preset condition and does not satisfy the second preset condition, when the pressure reduction operation is performed, the change amount of the pressure is a first set increment.

5. The pressure control method according to claim 3, characterized in that: When the supporting force does not meet the first preset condition, when the pressure reduction operation is performed, the change in the pressure is negatively correlated with the number of executions of the pressure reduction operation; and each time the pressure reduction operation is performed, the number of executions of the pressure reduction operation is correspondingly updated; When the boost operation is performed, the change in the pressure is negatively correlated with the number of times the boost operation is performed; and each time the boost operation is performed, the number of times the boost operation is performed is correspondingly updated.

6. The pressure control method according to claim 5, characterized in that: When the pressure reduction operation is performed, the pressure change is equal to the ratio of the second set increment to the number of times the pressure reduction operation is performed; When the pressure boosting operation is performed, the change in pressure is equal to the ratio of the second set increment to the number of times the pressure boosting operation is performed.

7. The pressure control method according to claim 6, characterized in that: The initial values ​​of the number of executions of the step-down operation and the number of executions of the step-up operation are 0; before executing the step-down operation, the number of executions of the step-down operation is updated; before executing the step-up operation, the number of executions of the step-up operation is updated; or, The initial values ​​of the number of executions of the step-down operation and the number of executions of the step-up operation are 1; after the step-down operation is performed, the number of executions of the step-down operation is updated; after the step-up operation is performed, the number of executions of the step-up operation is updated.

8. The pressure control method according to claim 7, characterized in that: After determining whether the supporting force is within the theoretical supporting force range, the method further includes: If the supporting force is within the theoretical supporting force range, the number of executions of the pressure reduction operation and the number of executions of the pressure increase operation are reset to initial values.

9. The pressure control method according to claim 3, characterized in that: When the comparison result is that the supporting force is less than the lower limit value, after determining whether the supporting force satisfies the first preset condition and the second preset condition, the method further includes: When the supporting force satisfies the first preset condition and the second preset condition, a critical pressure value is calculated according to the weight and the adsorption voltage value on the electrostatic chuck, the critical pressure value is assigned to the current value, and the step of obtaining the supporting force is returned.

10. The pressure control method according to any one of claims 1 to 9, characterized in that: The obtaining of the supporting force provided by the electrostatic chuck for the wafer specifically includes: Obtaining component forces respectively provided by a plurality of support columns arranged on the electrostatic chuck to the wafer, and determining the supporting force according to the component forces; Before determining whether the supporting force is within the theoretical supporting force range, the method further includes: Determine whether the difference between the component forces corresponding to every two of the support columns is less than a target threshold; wherein the target threshold is a ratio of the weight to a characteristic value, and the characteristic value is equal to the number of the support columns minus 1; If not, an alarm message is issued, wherein the alarm message is used to indicate that the adsorption state of the wafer is abnormal.

11. The pressure control method according to any one of claims 1 to 9, characterized in that: When the wafer is on the electrostatic chuck, start the timer; Before returning to execute the step of obtaining the supporting force, the method further includes: Determine whether the timing time exceeds the preset time; If so, an alarm message is issued, wherein the alarm message is used to indicate that the adsorption state of the wafer is abnormal.

12. The pressure control method according to claim 11, characterized in that: After determining whether the supporting force is within the theoretical supporting force range, the method further includes: If the supporting force is within the theoretical supporting force range, the timing time is cleared to 0.

13. The pressure control method according to any one of claims 1 to 9, characterized in that: After determining whether the supporting force is within the theoretical supporting force range, the method further includes: If the supporting force is within the theoretical supporting force range, obtaining the temperature of the heat medium gas between the wafer and the electrostatic chuck; When the temperature does not meet a preset threshold, a temperature control device for adjusting the temperature of the electrostatic chuck is controlled to adjust the temperature of the heat medium gas.

14. A semiconductor process equipment, characterized in that: include: Chamber; An electrostatic chuck is arranged in the chamber and is used to carry the wafer. The electrostatic chuck is provided with an air flow channel, the air inlet of the air flow channel is used to communicate with the air inlet device located outside the chamber, the air outlet of the air flow channel is located on the top surface of the electrostatic chuck, and the air inlet device is used to pass heat medium gas to the back side of the wafer; A voltage detection device, used to detect the adsorption voltage value on the electrostatic chuck; A pressure detection device, used to detect the supporting force provided by the electrostatic chuck for the wafer; A controller is electrically connected to the air intake device, the voltage detection device and the pressure detection device, the controller includes at least one processor and at least one memory, the memory stores a computer program, and the processor executes the computer program to execute the pressure control method described in any one of claims 1 to 13.

15. The semiconductor process equipment according to claim 14, characterized in that: A temperature detection device electrically connected to the controller is also included, and the temperature detection device is used to detect the temperature of the heat medium gas between the wafer and the top surface of the electrostatic chuck.

16. The semiconductor process equipment according to claim 14, characterized in that: It also includes a plurality of support pillars vertically arranged on the top surface of the electrostatic chuck, and the wafer is placed on the support pillars; There are multiple pressure detection devices, and the multiple pressure detection devices are arranged on the top ends of the multiple support columns in a one-to-one correspondence.

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